CN116830812A - PCB production with laser systems - Google Patents

Abstract

Systems and methods for printing a Printed Circuit Board (PCB) from a substrate to a fully integrated system utilize a Laser Assisted Deposition (LAD) system to print flowable material on top of the substrate by laser spraying to create a PCB structure for use as an electronic device. One such PCB printing system includes a jet printing unit, an imaging unit, a curing unit, and a drilling unit for printing metals and other materials (epoxy, solder resist, etc.) directly onto a PCB substrate such as a glass reinforced epoxy laminate (e.g., FR 4) or other material. The jet printing unit may also be used for sintering and/or ablation of materials. The printed material is cured by heating or by Infrared (IR) or Ultraviolet (UV) radiation. The PCBs produced according to the present systems and methods may be single sided or double sided.

Description

PCB production with laser systems

Cross-references to related applications

This application claims priority from U.S. Provisional Application No. 63/200,034, filed on February 11, 2021, and U.S. Patent Application No. 17/249,217, filed on February 24, 2021.

Technical field

The present invention relates to systems and methods for printing printed circuit boards (PCBs) or flexible PCBs from a substrate to fully integrated.

Background technique

Surface Mount Technology (SMT) is an area of electronics assembly used to mount electronic components to the surface of a PCB, as opposed to conventional assembly where components are inserted through holes in the PCB. SMT was developed to reduce manufacturing costs and allow efficient use of PCB space. Thanks to the introduction of SMT and increasing levels of automation, highly complex electronic circuits can now be built into smaller and smaller components with good repeatability.

The recent trend towards miniaturization has created a need to manufacture highly integrated PCBs. Printed circuit boards are typically manufactured by lithography using extraction methods such as etching. This manufacturing method provides conductive lines by placing a conductive film on a substrate and etching away unnecessary portions of the conductive film with an etching solution to dissolve and remove portions of the conductive film where circuits do not exist, leaving only necessary conductive lines. Formation. In addition, in order to increase the level of integration, multi-layer printed circuit boards and double-sided printed circuit boards are required. Current manufacturing of multilayer printed circuit boards requires complex processes including drilling to form vias or vias to enable conduction between multilayer boards, lamination, and soldering to adhere components to the printed circuit board. When soldering is performed to adhere a component to a printed circuit board, an area is also required in which the solder melts and expands, and therefore the component is located in a wider area than the size of the component itself, which limits miniaturization. Therefore, there is a need for equipment and methods that can efficiently and accurately manufacture complex circuit boards.

Flexible-rigid composite electronics represent a new generation of electronic devices that can exhibit both tensile and bending flexibility. These properties will enable electronic devices to adapt to bending and twisting and the ability to stretch and compress over large strain ranges. Due to their soft and comfortable nature, stretchable electronics show great potential in biomedical engineering, such as epidermal electronics and implantable devices. There is also growing demand for wearable electronics and other industries such as sensors, antennas with complex geometries or radio frequency identification (RFID) tags placed on curved objects.

Advances in the field of flexible electronics are expected to play a key role in many important emerging technologies. For example, flexible sensor arrays, electronic paper, wearable electronic devices, and large-area flexible active matrix displays. In addition, the development of flexible integrated electronic systems and processing methods is expected to have a significant impact on several other important technologies, including micro and nanofluidics, sensors and smart skins, RFID, information storage, and micro and nanoelectromechanical systems.

Flexible electronics currently refers to technologies that build electronic circuits by depositing electronic devices onto flexible substrates. Fabrication of flexible electronics with performance equivalent to conventional (rigid) microelectronic devices built on fragile semiconductor wafers, but with optical transparency, lightweight, stretchable/bendable format, and ease of rapid printing over large areas The devices have been shown to enable a variety of applications such as flexible displays, thin-film solar cells, and large-area sensors and actuators. In all of these applications, the flexibility of both the circuit and the components incorporated into it represents an important difference from typical rigid circuits. To date, designs that are bendable (determined by the Young's modulus, a modulus of elasticity describing a mechanical tension equal to A material property or parameter that is the ratio between the elongation and the corresponding elongation, and is therefore a measure of a material's hardness) and stretchability (determined by Poisson's ratio, which refers to a measure of the relative change in width with change in length, Or the tendency of components to "neck" during stretching) Electronics based on inorganic materials have proven to be a challenge. A typical implementation of flexible electronic devices employs thin-film inorganics as semiconductors, conductors, and/or insulators on a substrate to minimize strains caused by bending or stretching. Another embodiment is represented by a wave-patterned circuit that provides fully reversible stretchability/compressibility without significant strain in the circuit material itself.

Contents of the invention

The inventors have recognized the desire to have a "one-stop shop" for the production of PCBs; to replace the highly complex technology that currently uses approximately 20 stages to produce a single PCB board (excluding electronic component placement on the board) with one that performs all production stage and can even affect the placement of electronic components on the board.

The present invention therefore relates to systems and methods for printing (rigid or flexible) PCBs from substrate to fully integrated. Various embodiments of the present invention utilize a laser-assisted deposition (LAD) system to print a flowable material on top of a substrate via laser jetting to create a PCB structure that will be used as electronic devices in the production line. In one embodiment, a system for PCB printing includes a jet printing unit, an imaging unit, a curing unit, and a drilling unit that directly line the board with a material such as a glass reinforced epoxy laminate (e.g., FR4) or other materials. Printed on the bottom. Jet printing units can also be used for sintering and/or ablation of materials. The system prints copper and gold pastes, epoxy resins and solder masks and cures them with heat or ultraviolet (UV) radiation. This system can also print epoxy at the junctions of copper wires, for example, where the epoxy layer is printed as a bridge on top of the copper wires on the PCB. PCB boards produced according to the present system and method may be single-sided or double-sided.

In one embodiment, the present invention provides a method of manufacturing a PCB assembly in which a metal layer is deposited on a PCB substrate by an LAD in which metal droplets from a donor substrate are ejected onto the PCB using a laser onto the substrate and/or sprayed into one or more holes in the PCB substrate to form a metal layer on the PCB substrate. The metal layer is then dried and sintered, and spraying, drying, and sintering are repeated until the metal layer reaches the desired thickness. Then, at least one passivation layer is formed over the metal layer. If desired, the metal layer can be ablated if it exceeds the desired thickness (eg, using the same laser used for deposition). The passivation layer can be an epoxy layer deposited or coated over the metal layer using a roller or doctor blade. Alternatively the passivation layer may be an epoxy layer printed over the metal layer via LAD from an epoxy coating on the donor substrate. If desired, LAD can also be used to print one or more additional metal and epoxy layers. The epoxy layer can be cured by hot air and/or infrared (IR) radiation.

In some examples, the metal layer will include a first metal trace and the epoxy layer will include at least a first portion of epoxy covering at least a first portion of the first metal trace. The additional metal layer printed over the epoxy layer may thus include a second metal trace having at least a first portion of the epoxy layer disposed over the first portion of the first metal trace. part. That is, the epoxy layer can form a bridge through which a second metal trace can intersect a first metal trace on the same die of the PCB substrate without causing a short circuit.

In some cases, one or more holes in the PCB substrate will be formed in the first side of the PCB substrate by drilling or laser engraving the first side of the PCB substrate, but these holes will not pass through through the entire thickness of the PCB substrate. A metal layer can then be formed by LAD in one or more holes from a first side of the PCB substrate; that is, the side on which the holes exist. The PCB substrate can then be turned over and one or more holes through the thickness of the PCB substrate are made by drilling or laser engraving through the second (opposite) side of the PCB substrate. The remainder of the hole or holes exposed by drilling or laser engraving through the second (opposite) side of the PCB substrate can then be metallized by LAD in the manner discussed above.

Where desired or required, the solder mask is printed over the passivation layer and any intervening layers and/or components of the PCB assembly, such as by LAD. Additionally, the label can be printed on top of the solder mask, such as by LAD. Holes and vias in various layers (including solder mask) are formed and metallized by LAD as needed to provide electrical connections to the metal layers in the PCN assembly and to provide attachment points for electronic devices.

In other embodiments, the present invention provides a method of manufacturing a PCB assembly, the method comprising printing metal onto an epoxy laminate via LAD, the metal being applied as droplets from a metal coating on a donor substrate. Layers or foils are laser sprayed into the channels and/or holes created in the epoxy laminate by laser engraving; and the epoxy laminate is subsequently attached to the PCB substrate or disposed on the PCB by heat pressing A previously formed epoxy layer over a substrate where the metal sprayed into the channels and/or holes of the epoxy laminate is on top of the epoxy laminate in the portion of the PCB substrate and PCB assembly between surfaces. The solder mask may be printed by LAD or otherwise over the upper surface of the epoxy laminate and any intervening layers and/or components of the PCB assembly, and the label may be printed on the solder mask.

In additional embodiments, the present invention provides a system for manufacturing a PCB assembly, wherein a substrate holder configured to hold a PCB substrate is translatable between a plurality of processing stations, the plurality of processing stations including: A printing station configured for LAD of one or more materials (e.g., copper and gold pastes, epoxy resins, solder mask materials, etc.) by converting a corresponding material is ejected from a corresponding donor substrate on which a corresponding one of the materials is coated or otherwise disposed; and a curing station configured to cure the deposition by heating, IR radiation, or UV radiation. said material on a PCB substrate; and a drilling station configured to drill or carve through vias in the PCB substrate and/or said layer of material disposed on the PCB substrate and/or through holes. The printing station may also be configured for laser sintering and/or laser ablation of the respective ones of the materials printed on the PCB substrate and/or additional layers of the PCB assembly. A unit may also be provided that is configured to flip the PCB substrate to allow the printing station, curing station and/or drilling station to access both sides of the PCB substrate.

In yet another embodiment, the present invention provides a method for manufacturing a printed circuit board PCB assembly, wherein one or more through holes are drilled or laser engraved in a PCB substrate from a first side of the PCB substrate. Vias do not extend through the entire thickness of the PCB substrate. A metal slurry is deposited by the LAD over at least a first portion of the PCB substrate and into one or more of the vias to a first thickness. The deposition is performed by ejecting a small volume of metal slurry from the donor film on the first carrier substrate onto the PCB substrate and into one or more through holes by an incident laser beam; depositing Solidification of the metal paste on the PCB substrate and into one or more vias; sintering the deposited and solidified metal paste using the same laser used to deposit the metal paste; and repeating the deposition, solidification of the metal paste and sintering to form a continuous thickness of metal paste on the PCB substrate and in the one or more through holes until a desired thickness of the metal paste on the PCB substrate and in the one or more through holes is reached. The passivation layer is then printed by LAD over the desired thickness of metal paste on the PCB substrate and in one or more vias; printing is performed from a second carrier using the same laser used to deposit the metal paste The substrate is sprayed with a small volume of epoxy, and the passivation layer is cured. Finally, a solder mask is formed over the passivation layer by LAD, which involves ejecting a small volume of solder mask material from the third carrier substrate and curing the solder mask using the same laser used to deposit the metal slurry. The solder mask, passivation and metal slurry layers can be cured using heat, or IR or UV radiation.

In various examples, the PCB substrate moves between drilling, deposition, printing, and forming processes on a platform that can translate between locations where the drilling, deposition, printing, and forming processes occur. Additionally, the process of depositing metal slurry and printing passivation layers can be performed multiple times before forming the solder mask to create multiple metal slurry and epoxy layers between the PCB substrate and the solder mask (e.g. , on one or both sides of the PCB substrate) PCB assembly. Metallic electrical connectors for electronic components can be formed within the passivation layer and/or solder mask, and the metal electrical connectors can be formed from different metals (eg, Cu, Au, Ag, etc.). One or more electronic components may be attached to the metal electrical connector, such as by one or more solder joints, and in some examples, one or more additional passivation layers and/or solder mask layers may be formed over the electronic components . When needed, a support structure for the electronic components can be formed by LAD before attaching the electronic components. Additionally, as discussed above, epoxy bridges can be used to avoid shorts between different electrical trace layers.

These and other aspects of the invention are described in greater detail below.

Description of the drawings

The invention is illustrated by way of example and not by way of limitation in the figures of the accompanying drawings, in which:

Figures 1a to 1d illustrate in a conceptual manner different processes for forming vias in PCBs.

Figures 2a to 2c schematically illustrate a process of printing a metal layer into a via according to an embodiment of the invention.

Figure 2d shows one example of printing on the edge of a via to form a metal coating on the wall of the via according to an embodiment of the present invention.

Figures 3a and 3b illustrate various alternatives for the metal printing process stages.

Figures 4a and 4b illustrate various ways of printing an epoxy resin layer onto the surface of a PCB, either by a roller or a doctor blade (Figure 4a) or by direct printing (Figure 4b), according to embodiments of the present invention.

Figure 4c shows the heating of a PCB produced according to the method shown in Figures 4a and 4b to achieve final laminate properties.

Figures 5a to 5c illustrate additional methods of creating a PCB by carving a solid laminate (Figure 5a), printing a metal layer onto the laminate (Figure 5b), and drying and pressing the previous layers (Figure 5c) .

Figures 6a to 6c illustrate the creation of a PCB by carving a solid laminate after pressing against the previous layers (Figure 6a), and then printing a metal layer onto the laminate (Figure 6b) and drying (Figure 6c) Additional additional methods.

Figures 7a to 7c show solder mask being printed onto a PCB (Figure 7a to 7b) and cured by heat or UV light (Figure 7c).

Figures 8a and 8b show the label being printed onto a PCB (Figure 8a) and cured by heat or UV light (Figure 8b).

Figures 9a and 9b illustrate aspects of how the method and system of the present invention can eliminate the need for a double-sided PCB by using an epoxy bridge on one side of the PCB, thereby reducing PCB processing time.

Figures 10a and 10b illustrate aspects of a system for complete production of PCBs according to embodiments of the invention.

11a to 11g illustrate aspects of the production cycle of a multilayer PCB from substrate to final board according to embodiments of the present invention.

12a to 12d illustrate aspects of the production cycle of a double-sided multilayer PCB board from substrate to final board according to an embodiment of the present invention.

Figures 13a-13i illustrate aspects of the production cycle of a PCB with embedded electronics according to embodiments of the present invention.

Figures 14a-14d illustrate aspects of a PCB production cycle where laser-assisted deposition is used for some aspects of PCB manufacturing.

Detailed ways

PCB production is a highly developed field with many stages. The aim of the invention is to simplify the production process by providing and using as a one-stop a single system with several sub-modules that can build a PCB from prepreg and laminate level to full development with embedded electronics board. Systems and methods configured in accordance with the present invention do not necessarily require the use of different materials used in conventional PCB production today (although such new materials may be used), but rather may use those same materials in new and different ways. Accordingly, in various embodiments, the present invention relates to systems and methods for going from substrate level to fully integrated printed PCB or flexible PCB. As described below, embodiments of the present invention can utilize a LAD system to print any flowable material on top of a substrate via laser jetting to create a PCB structure that will be used as electronic devices in the production line.

The first stage of PCB production involves drilling through holes in the board substrate. As shown in Figures 1a to 1d, any of several methods may be used. For example, and referring to Figure 1a, in PCB board production system 100a, CNC machine 102 may be used to drill holes into PCB core substrate board 104. As noted, the PCB core substrate plate 104 may be made from a glass reinforced epoxy laminate material such as FR4. Such modules, including those with an additional cleaning unit for removing drilling waste, are widely used today. The CNC head 102 is mounted on a three-dimensionally movable platform (not shown) and the substrate plate 104 remains flat from its sides or on a sacrificial substrate (not shown in this view). The drill bit 102 creates holes 106 at desired locations on the plate 104, optionally having different diameters. In current systems, drilling only through holes and not vias is beneficial because the laser can be used to remove excess material after flipping the board, simplifying copper paste placement in the holes and keeping the substrate holder clean ( Via holes can contaminate the retainer surface).

As explained below, other aspects of PCB board production systems are laser-based. Therefore, all engraving or cutting involved in PCB production, including the formation of through-holes, can be done using lasers instead of CNC drills. To this end, Figure lb shows an embodiment of a PCB board production system 100b using a laser system 110 to engrave through holes. When using laser 110, a power meter or intensity meter 112 may be used to evaluate hole depth. By measuring the light intensity at the location of the via during laser drilling, the via depth can be evaluated (e.g., by a lookup table or other means) in order to stop drilling before the hole penetrates the entire thickness of the board substrate 104 (e.g., so that the thickness "z" of the substrate remains). The measured light intensity may be that of the cutting laser beam 114 itself or that of a separate light source (eg, a light source positioned above the cutting location).

As mentioned, only drilling/cutting vias instead of vias simplifies cleaning of the substrate holder. However, referring to the PCB board production system 100c shown in FIG. 1c, another solution that may be employed is to add a peelable substrate 108 underneath the PCB substrate 104. For example, the peelable substrate 108 may be added to one side of the PCB substrate 104 and, after drilling and cleaning the opposite side, the peelable substrate 108 may be removed to allow the initial placement of the PCB substrate 104 to be Peel off the side of the substrate to drill. Where releasable substrate 108 is used, appropriate coating and stripping units are added to the system to allow these operations.

Referring now to Figure 1d, yet another method of keeping the sample holder 120 of the PCB board production system 100d clean is to use a sacrificial layer 116 (eg, made of plastic or similar material) between the sample holder 120 and the PCB substrate 104. . In this case, the sacrificial layer 120 should be able to keep the PCB substrate 104 flat. Typically, the sample holder 120 is a vacuum holder that holds the PCB substrate 104 flush with the holder surface, but if a sacrificial layer 120 is added, the sacrificial layer should be able to maintain the vacuum on the PCB substrate 104. Therefore, some holes 118 must be added in the sacrificial layer 116 such that a vacuum is maintained relative to the PCB substrate 104, and the holes should be located away from the location of the drilled holes 116. For each application, a new sacrificial layer 116 must be designed (to account for the location of the drill holes), and the new sacrificial layer can be used multiple times.

Turning now to the metallization process, in embodiments of the invention this may be performed by paste printing. Figure 2a shows how in a PCB board production system 200, an uneven surface, such as a PCB substrate 104 in which vias 106 have been carved/drilled, can be covered with a metal slurry 202 by laser induced jetting. Laser induced jetting is a form of LAD in which a laser beam 204 is used to create a patterned surface through controlled deposition of material. Specifically, laser photons provide the driving force to eject a small volume of material 206 from the donor film 208 toward a recipient substrate such as the PCB substrate 104 . Typically, laser beam 202 interacts with the inner side of donor film 208 that is coated onto non-absorbent carrier substrate 210 . In other words, the incident laser beam 204 propagates through the transparent carrier substrate 210 and the photons are absorbed by the inner surface of the film 208 . Above a certain energy threshold, material 206 is ejected from the donor film 208 toward the surface of the PCB substrate 104 located on a platform (not shown in this view) in the work area.

Once deposited on the PCB substrate 104, including within the vias 106, the metal paste 202 is dried by hot air 212, see Figure 2b, or by heating using an infrared (IR) lamp or similar arrangement, and the resulting Metal film 214 may be sintered using a laser beam 216 passed through the deposited metal slurry to produce a highly conductive metal (eg, copper) film as shown in Figure 2c. The same laser used for slurry deposition can be used for sintering, and can also be used to ablate deposited material that is not positioned correctly—repairing it online for added robustness.

Since the printing of the conductive film is an intermediate step, it is expected that the formation of this layer will not take a long time. Therefore, the material from which the conductive film is formed should only take a short time to cure (whether by infrared radiation, hot air, or both) and should not shrink much, if at all, during the curing process. Materials that take too much time to cure will hinder the overall speed of the process, and those that shrink (at least more than a little) during curing will impart mechanical stress on the PCB substrate that can lead to failure.

Active or conductive materials for conductive films may include one or more metals. Metals contemplated include pure metals, metal alloys and refractory metals. Copper is a common choice for PCB metallization and can be used in embodiments of the present invention. Active materials can be applied (printed) from the solid state using LAD, for example small metal particles deposited on a plastic film can be used in the LAD process to create a conductive layer, or as a slurry supported on a donor film as described above form application (printing). The amount of conductive film applied should be sufficient to fully support subsequent electrical connections. This can mean applying several layers of slurry, one on top of the other, with a curing step after each layer is applied. As shown in Figure 2d, the laser jet process is highly precise and can be used to print the metal paste 208 directly on the edge 220 of the via 106, thereby achieving a method of only coating the via without filling the via. This approach may be of some importance in the case of large and/or deep vias.

Figure 3a schematically shows one embodiment of the metallization process. First, holes or tracks 302 are printed by laser jetting (or otherwise) metal (eg, Cu) (i.e., in the case of holes, the holes are filled, and in the case of tracks or traces, the tracks or traces are lines are deposited on a PCB substrate or other layer), the solvent is then dried 304, and the metal is sintered 306. At this stage, the plate may be brought to the imaging unit to verify that the desired hole or track thickness (eg, in the case of holes, fill level) is achieved 308 . If so, the board proceeds to the next stage; otherwise, the board is returned for additional printing/deposition, and the process is repeated until the desired amount of metal has been printed (i.e., the desired thickness is reached). As shown in Figure 3b, in other embodiments, additional ablation steps may be added before (or after) the sintering step to remove excess deposited material.

After metallization, at any layer, a dielectric layer can be added to the board to reduce capacitance and avoid short circuits. There are several methods of adding dielectric layers, for example, by applying a liquid material and curing it or by hot pressing the prepreg. Examples of such processes will now be explained.

Referring to Figures 4a and 4b, a dielectric layer 408, which can be an epoxy and acts as a passivation layer, can be deposited or coated over the metal (or other) layer and/or PCB substrate by means of a roller or doctor blade, see Figure 4a; or by using a laser jet system to print the dielectric layer from the donor film, as shown in Figure 4b. In the case of applying liquid epoxy 402 using a roller 404 or a doctor blade, the epoxy may be a viscous liquid including fillers such as silica spheres. A quantity of epoxy 402 is applied to one end of the plate and a roller 404 is placed at the desired height above the metal layer 214 and moved laterally over the plate to spread the epoxy 402 to the desired thickness. "h" expands into layer 408 in a uniform manner, and the roller may be made of or coated with an anti-stick material such as Teflon, ceramic, silicone, or other materials. In some cases, the position of the roller 404 can be fixed and the plate moved underneath the roller to allow the epoxy to spread. Where a blade applicator is used instead of a roller, the angle of the blade relative to the plate will affect the vertical force exerted on the epoxy. If the angle is too tight, the epoxy may not be squeezed into the small holes between parts of the metal layer. At the same time, if the squeegee pressure is too low, it may prevent the epoxy from being applied cleanly to the board, and if the squeegee pressure is too high, it may cause the epoxy to leak beyond the desired coverage area. Therefore, an adjustment device for the scraper angle should be provided, and the scraper angle should be adjusted according to the viscosity and other characteristics of the epoxy resin.

Alternatively, as shown in Figure 4b, the epoxy 402 can be applied in a thin layer to the substrate or foil 404 and then laser jetted by laser jetting using the same laser that generates the beam 204 that is also used to jet the metal layer. Deposited in small amounts 406 (eg, droplets) onto metal layer 214 and/or PCB substrate 104. Epoxy 402 may be applied to a substrate 404 that is transparent or nearly transparent at the wavelength of laser beam 204 by a roller system in which the substrate is passed between a pair of rollers separated by a well-defined gap or A single roller is passed between the fixed surface to ensure that the resulting epoxy 402 coating has a uniform thickness. For example, such a coating system may include a syringe of epoxy and an air or mechanical pump that drives the epoxy onto substrate 404. The substrate 404 can then be moved toward the well-defined gap to create a uniform epoxy 402 layer having a thickness defined by the gap. In some embodiments of the invention, the substrate 404 can be translated bi-directionally in a controlled manner while opening the gap between the coating rollers, thereby creating the possibility to recoat the same area of the substrate 404 with epoxy without contaminating the rollers. properties and reduce or eliminate the amount of substrate 404 consumed during the coating process, thereby preventing waste.

Once coated, the substrate 404 with the epoxy 402 layer thereon is positioned in the laser jetting system, and the laser beam 204 is used to jet dots 406 of the epoxy 402 onto the metal layer 214 and/or the PCB substrate 104 superior. In one example, the laser beam 204 is focused onto the interface between the epoxy layer 402 and the substrate 404, causing localized heating followed by a phase change and high local pressure that drives the epoxy to be ejected into the metal layer and/or on the PCB substrate. After printing the epoxy onto the metal layer and/or PCB substrate, the substrate 404 can be moved through the coating system by reversing the direction of the transport mechanism or in a cycle-like process if the substrate 404 is a continuous film. The substrate 404 is returned for a second (or additional) application of epoxy 402 .

In yet other embodiments, the substrate 404 can be a screen or grid, with the epoxy 402 introduced into the holes of the screen via an applicator, which can be a roller or a doctor blade, and using an incident The laser beam 204 displaces the epoxy from the holes in the mesh onto the metal layer and/or PCB substrate.

Referring to Figure 4c, after printing or coating the epoxy layer 408, heat is applied to the layer via hot air, IR radiation, and/or other heating methods, and the epoxy layer is cured.

Yet another method of passivation is to use laminates to form a passivation layer. The use of laminates reduces height differences in the surface and creates a PCB surface with a more uniform height. Laminated passivation layers can be formed in two different ways: by printing metal (e.g., Cu) onto the laminate and attaching the resulting structure to the surface (Figure 5a to Figure 5c) or by attaching the laminate to surface of the PCB and prints metal (e.g., copper) into open vias (Figures 6a to 6c).

In a first process, and referring to Figures 5a-5c, laminate film 502 is attached to liner 504 and a laser beam 506 is used to separate the layers, for example by creating vias 508 and/or channels 510 in the laminate. The pressing is engraved/cut into the desired configuration. Metal (eg, Cu) 202 is deposited from film 208 coated on substrate 210 using laser beam 204 to fill the engraved areas with the metal, and only then is laminate 502 attached (eg, by heat pressing). Layers are connected to the PCB substrate 104 (or previously formed laminate layers) to create both metal and passivation. This approach significantly improves the efficiency of the PCB build cycle because the construction of layers and the attachment of layers can be done as two independent stages, allowing them to be serialized.

Other advantages may be achieved by attaching a laminate 602 (eg, an epoxy laminate) to the PCB substrate 104 and then engraving the laminate using a laser beam 606 (as shown in Figure 6a). This method is more stable to thermal effects during the hot pressing stage when the laminate is attached to the PCB substrate. After engraving, the vias and holes are filled with metal in the manner described above (Fig. 6b), and hot air 410 is applied to the surface of the plate to dry the metal (Fig. 6c). Additional laser sintering can be added to enhance the conductivity of the metal particles.

In the final part of PCB production, the board is coated with solder mask. By acting as a protectant for the underlying layer, solder mask allows the use of high temperatures to solder electronic components to the board without damaging the inner layers of the board. As shown in Figure 7a, one method for printing solder mask 702 is by laser jetting. Similar to how a layer of printed epoxy is printed, the solder mask material 704 may be applied in a thin layer to the substrate or foil 708 and then deposited in small amounts 710 (e.g., droplets) onto the metal layer 214 by laser jetting using a laser beam 706 and/or on the PCB substrate 104. Laser beam 706 may be generated by the same laser also used to eject metal and/or epoxy layers. The solder mask material 704 may be applied to a substrate 708 that is transparent or nearly transparent at the wavelength of the laser beam 706 by a roller system in which the substrate is passed between a pair of rollers or a single roller separated by a well-defined gap. between the roller and the fixed surface to ensure that the resulting coating of solder mask material 704 has a uniform thickness. For example, such a coating system may include a syringe of solder mask material and an air or mechanical pump that drives the solder mask material onto substrate 708 . The substrate 708 can then be moved toward the well-defined gap to create a uniform layer of solder mask material 704 having a thickness defined by the gap. In some embodiments of the invention, the substrate 708 can be translated bidirectionally in a controlled manner while opening the gap between the coating rollers, thereby creating the possibility to recoat the same areas of the substrate 708 with solder mask material without contaminating the rollers. properties and reduce or eliminate the amount of substrate 708 consumed during the coating process, thereby preventing waste.

Once coated, the substrate 708 with the layer of solder mask material 704 thereon is positioned in the laser jetting system, and the laser beam 706 is used to jet dots 710 of the solder mask material 704 to the metal layer 214 and/or the PCB substrate 104 superior. In one example, the laser beam 706 is focused onto the interface between the solder mask material 704 layer and the substrate 708, causing local heating followed by a phase change and high local pressure, which drives the solder mask material to be ejected into the metal layer and/or on the PCB substrate. After printing the solder mask material 702 onto the metal layer and/or PCB substrate, the substrate 708 can be moved through the coating system by reversing the direction of the transport mechanism or in a cycle-like process if the substrate 708 is a continuous film. , to return substrate 708 for a second (or additional) application of solder mask material 704 .

Once the solder mask 702 has been printed, see Figure 7b, UV light 714 and/or heat is used to cure the solder mask to create a mask layer that is open only in the solder area 712, as shown in Figure 7c.

It is often useful to have labels on the top of the PCB board to help the technician understand the purpose of each part and to indicate to the technician the area on the PCB board. To do this, an additional label layer 802 can be added on top of the solder mask layer 702 . Label layer 802 may be printed by inkjet, screen printing, or other printing methods, and in one embodiment, by the same laser jet system used to print solder mask.

As shown in Figure 8a, label material 804 may be applied in a thin layer to a substrate or foil 808 and then deposited in small amounts 810 (eg, droplets) onto the solder mask 702 by laser jetting using a laser beam 806. Laser beam 806 may be generated by the same laser that is also used to spray metal layers, epoxy layers, and/or solder mask layers. Label material 804 may be applied to a substrate 808 that is transparent or nearly transparent at the wavelength of laser beam 806 by a roller system in which the substrate is passed between a pair of rollers or a single roller separated by a well-defined gap. and the fixed surface to ensure that the resulting coating of label material 804 has a uniform thickness. For example, such a coating system may include a syringe of label material and an air or mechanical pump that drives the label material onto substrate 808. The substrate 808 can then be moved toward the well-defined gap to create a uniform layer of label material 804 having a thickness defined by the gap. In some embodiments of the invention, the substrate 808 can be translated bi-directionally in a controlled manner while opening the gap between the coating rollers, thereby creating the possibility of recoating the same area of the substrate 808 with label material without contaminating the rollers. , and reduce or eliminate the amount of substrate 808 consumed during the coating process, thereby preventing waste.

Once coated, the substrate 808 with the layer of label material 804 thereon is positioned in the laser jetting system and the laser beam 806 is used to jet dots 810 of the label material 804 onto the solder mask 702 . In one example, the laser beam 806 is focused onto the interface between the label material layer 804 and the substrate 808 , causing localized heating followed by a phase change and high local pressure that drives the label material to be ejected onto the solder mask layer 702 . After printing the label layer 802, the substrate 808 can be returned to the label material by reversing the direction of the transport mechanism or moving the substrate 808 through the coating system in a cycle-like process if the substrate 808 is a continuous film. Second (or additional) coating of 804.

Once the label layer 802 has been printed, the label layer is cured using UV light 814 and/or heat, as shown in Figure 8b. The curing station can be the same one used to cure the solder mask.

One of the advantages of a PCB production system configured in accordance with embodiments of the present invention is its ability to reduce costs and production time associated with multi-layer PCB boards. Current production processes for boards using more than one metal layer are complex. The present invention provides systems and methods encompassing a wide range of applications that allow the direct and rapid production of boards with more than one metal layer. For example, although conventional PCB production processes do not include making simple bridges between metal lines, such bridges can be accomplished very easily in a system configured in accordance with the present invention.

Figure 9a shows an example of a PCB 900 including intersecting metal (eg, Cu) lines 902, 904, 906. Using conventional PCB production processes, making PCB 900 would require several production stages, even if possible, consuming a significant amount of production time. It may even be necessary to use a double-sided PCB. However, in PCB production systems employing the method of the present invention, production complexity and time are significantly reduced. For example, using one or more of the techniques described above, laser jetting may be used to print epoxy patches 910, 912, allowing metal lines 902, 904, 906 to be printed on a single side of PCB 900, and optionally The metal lines are printed using the same laser jet unit used to print the epoxy patches. Figure 9b provides a close-up three-dimensional view of one of the wire intersections on PCB 900 shown in Figure 9a. After printing the metal line 902, the epoxy patch 910 can be printed such that subsequent metal lines 904 cross the line 902 on the same side of the PCB 900 without creating a short circuit. This simple example shows how complex double-sided panels of the past can be made in a relatively simple way using laser jetting techniques of different materials as discussed above. Of course, the present system and method can also be used to make double-sided PCBs with or without bridge structures such as epoxy patches 910, thereby facilitating the production of single- and double-sided panels with bridged and non-bridged areas.

Turning now to Figures 10a and 10b, examples of PCB processing systems 1000a and 1000b configured in accordance with embodiments of the present invention are shown. Figure 10a shows a system 100a consisting of individual sub-units, while Figure 10b shows a system 1000b in which the sub-systems are arranged into various modules. In these examples, PCB processing systems 1000a and 1000b include imaging subsystem 1003 and laser subsystem 1004, which together may be organized into printing unit 1002, which may include. UV photonic system 1008 may be included in UV curing unit 1006, although this is an optional component. Heating subsystem 1012 may be a component of heating unit 1010. Additionally, a drilling unit 1014 including the CNC drilling head 102 described above and a three-dimensional translation subsystem 1016 for maneuvering the drill head may be provided as a module, or the components may be provided separately. Optionally included in the drilling unit 1014 or elsewhere may be a PCB flipping subsystem 1018 configured to flip the PCB during processing to allow drilling, printing, etc. on both sides of the PCB. . Where laminates are used, an optional heat press subsystem 1020 is available. Provided in association with the printing unit 102 are various materials 1022 for use in the LAD process discussed above. These materials include metals (eg, Cu) for conductive traces, solder masks, epoxies, etc., as well as the donor substrate on which these materials are coated for deposition onto the PCB. Although not shown in the figure, the printing unit 1002 may include only the laser subsystem for all laser deposition processes, and the printing unit may also include an inkjet head or screen printer for printing labels or solder mask materials.

Although not discussed in detail above, the methods of imaging subsystem 1003 may be employed in conjunction with any or all of the etching and deposition processes described above. For example, the imaging subsystem may include one or more two- and/or three-dimensional imaging units (eg, cameras, scanning laser arrangements, etc.) that image the PCB or portions thereof at various stages during the printing process. Vias and holes or features can be imaged to ensure they are free of debris and regular in shape. Deposited layers can be imaged to ensure they are evenly covered and/or precisely positioned. This may be particularly important where layers are printed by continuously ejecting small droplets of material. Imaging can also be used to ensure accurate registration of PCB substrate 102 on holder 120 . Imaging in this way allows for in-circuit repair of process steps, such as additional or re-coating layers, or if necessary re-spraying the PCB being processed. A platform 1030 that can translate in two dimensions and raise and lower the PCB 102 as necessary facilitates movement of the PCB between various units of the system 1000 during processing and between subsystems within those units.

As mentioned, UV photonic system 1008, whether modular or not, is optional. Since all deposited layers are thermally curable, the use of UV curing is not mandatory and therefore a UV photonic system is only required if UV curing is preferred. When modular, UV photonic system 1008 can be included or removed from the overall system as desired.

Heating subsystem 1012 is used to cure heat-sensitive materials and/or to dry solvent-based materials. The heating subsystem may be part of the overall system 1000a, but is preferably modularized 1010 so that it can be easily replaced in system 1000b if necessary.

Drilling unit 1014 is used to create holes and vias in the laminate, as discussed above. As previously explained, the drilling unit 1014 may be a CNC head 102, or a laser-based cutting and engraving unit, or a combination of both. Although the CNC head and/or laser cutting tool may be incorporated into a larger system such as 100a, a modular drilling unit 1014 is preferably used in order to isolate debris generated during the drilling process. After drilling, apply a cleaning procedure to the PCB board by adding a protective film before drilling, by cleaning the surface with air pressure and suction, or by other cleaning processes.

In the case where a solid laminate is used as the base of the PCB, an additional thermal press subsystem 1020 is used to attach the laminate to the PCB substrate 104 .

Figures 11a-11g illustrate various aspects of the production cycle of a single-sided, multi-layer PCB, and Figures 12a-12d illustrate various aspects of the production cycle of a double-sided, multi-layer PCB, each in accordance with implementations of the present invention. way of production cycle from substrate to final board. Starting with the single-sided, multi-layer PCB 1100 shown in Figure 11a, the PCB substrate 1102 may be an FR4 board or a flexible board. A first copper (or other) cladding layer 1104 is formed on the PCB substrate 1102 and covered by an epoxy layer 1106 . One or more vias 1114 may be provided in the epoxy layer 1106a to electrically connect the copper cladding layer 1104 to a second copper (or other metal) structure disposed on the upper side of the epoxy layer 1106a Layer 1108. Vias may be formed by a drilling process as described above with copper or other metal connectors deposited therein. The upper copper structural layer 1108 is also covered by an epoxy layer 1106b. This structure can be repeated for as many copper (or other metal) layers as desired, with vias 1116 provided with copper or other metal connectors as desired. Finally, the topmost copper layer is covered by solder mask 1110 and gold, silver, or other metal connectors 1112 may be added to allow electrical connection to individual copper wires 1106, 1108 through metallized vias 1116, 1114. Gold, silver or other metal connectors 1112 enable soldering of electronic components to the PCB board. Examples for forming a single-sided, multi-layer PCB 1100 and its components are discussed with reference to Figures 11b-11g.

As shown in Figure 11b, the fabrication of a single-sided, multi-layer PCB begins by obtaining a PCB substrate (FR4 or other) 1102 with a copper (or other metal) cladding layer 1104 disposed on one side thereof. PCB substrates can be purchased with copper cladding layers, and in one embodiment of the invention, these PCB substrates can be used as starting materials and the copper cladding layers can be laser etched to remove excess material, thereby creating a base layer on the PCB substrate. Leave the desired Cu line form on the bottom. Alternatively, as shown, a bare substrate (FR4 or other) 1120 may be provided to a laser jetting station such as described above, and a copper layer 1122 coated on the donor substrate 1124 by laser jetting using a laser beam 1126 to create copper (or other metal) lines on one side of the bare substrate. Once any solvent has dried, the copper layer 1128 sprayed onto the surface of PCB substrate 1120 is sintered and excess copper is removed by ablation. The same laser 1126 may be used to perform the sintering and ablation processes, albeit at different energies than used for the ejection process. Alternatively, different lasers can be used for sintering and ablation.

After the first copper layer is formed, a second layer is added to form connectors to additional layers. FIG. 11 c shows one example for printing a copper connector 1134 on top of a first copper layer 1132 on a PCB substrate 1130 . In this example, printing is performed by ejecting copper droplets from a copper film or coating 1138 supported on donor substrate 114 in the manner described above. Laser 1136 is used to eject a sufficient number of droplets per connector 1134 . The connector 1134 is then sintered and, if necessary, ablated to form a precise shape with the desired dimensions. As before, the same laser 1136 used to print the connector can be used, with different energies if desired, to perform sintering and ablation. After the copper connector is sintered and ablated, the epoxy layer 1146 is added by laser ejection of the epoxy coating 1142 carried on the donor substrate 1144 . The same laser 1136 can be used to print the epoxy layer 1146 and subsequently, the epoxy layer 1146 is heated 1148 to cure the layer.

In an alternative process, as shown in Figure 11d, an epoxy layer 1146 is printed by laser jetting onto the first copper layer 1132, the epoxy layer is cured, and then a connection will ultimately be formed in the epoxy layer Ablation hole/through hole 1148 at the location of the device. Copper connectors 1134 are then printed via laser jetting in the holes/vias 1148 created in the epoxy layer. Additional drying and sintering complete the structure. The process shown in Figure 11c or Figure 11d can be repeated multiple times to create a multi-layer structure 1150 as shown in Figure 11e.

Once the desired number of metal (eg, copper) and epoxy layers are formed, electrical connectors and solder mask can be printed. Figure 11f shows an example of such a process. First, a gold connector 1152 is printed on top of the copper connector 1134 via laser jetting to create a conductive connection. The laser jet process uses a laser beam 1158 to jet gold droplets from a gold film or gold slurry 1154 coated on a donor film or substrate 1156, as described above. The gold connectors 1152 are then dried and sintered, and ablated if necessary, and a solder mask 1160 is spray printed on the surface epoxy layer and resisted by heat and/or UV light 1166 The solder layer solidifies. The laser used for sintering, ablation (if necessary) and printing of the solder mask can be the same as the laser used for printing gold connectors and/or the laser used for printing copper connectors, with the energy adjusted accordingly.

As shown in Figure 11g, this is achieved by first jet printing the solder mask 1160, curing the solder mask by heat or UV radiation 1166, and then ablating the solder mask 1160 to create holes 1168 for placement of gold connectors 1152. Same result. Gold connectors 1152 were printed and sintered as described above.

The process used to form a double-sided, multi-layer PCB is similar to the process described above for creating a single-sided, multi-layer PCB, except that some adjustments are required due to the need to drill holes from both sides. Referring to Figure 12a, a double-sided, multi-layer PCB 1200 includes a PCB substrate 1202, on each side of which are one or more metal (eg, copper) layers (traces) 1202, each metal layer Separated by epoxy layer 1204. On each side, the final epoxy layer is covered by solder mask 1206, and gold (or other metal) connectors 1208 are added where the electronic components will be connected. Gold connectors 1208 are electrically connected to the lower copper layer through copper (or other metal) filled vias and holes 1210 in the epoxy layer.

There are different available alternatives for providing holes on each side of PCB substrate 1202. Referring to Figure 12b, in one embodiment, one or more via holes 1220 may be drilled in the PCB substrate 1202 with the drilling tool passing through the entire thickness of the PCB substrate. In this case, a peelable substrate 1222 is preferably subsequently provided under the PCB substrate 1202 after drilling is completed to accommodate jet printing of copper (or other metal) filler into the holes without contaminating the sample holder. Additionally, a sample holder 1224 should be used that holds the PCB substrate from its edge. Using laser 1228, printed copper (or other metal) is ejected from film or slurry 1230 on donor substrate 1232 in the manner described above to fill holes 1220. The copper filler 1226 is then sintered (eg, using the same laser 1228) in place in the hole. Peelable substrate 1222 and sample holder 1224 may then be removed.

Referring to Figures 12c and 12d, another option is to drill holes 1240 on one side of the PCB substrate 1202, noting that the holes 1240 do not go all the way through the entire thickness of the PCB substrate. As before, holes 1240 are filled with copper 1226 by jet printing from copper film 1230 supported on donor substrate 1232, and the copper fill is subsequently dried, sintered, and ablated (if necessary). Then, referring to Figure 12d, the PCB substrate 1202 is turned over, and a laser 1228 is used to complete the via hole by removing the remaining portion 1242 of the PCB substrate opposite the Cu fill 1226. This leaves small holes 1244 to be filled with copper by jet printing as described above, and the printed copper 1246 is dried and sintered also as described above.

Pick and place machines can also be added to the system to provide complete assembly of PCBs with electronic components. Figures 13a-13i illustrate several examples of the use of such machines to facilitate the inclusion of embedded and other electronic components in accordance with embodiments of the present invention. In these examples, single-sided, multi-layer PCBs are discussed. This is primarily for ease of illustration; however, it should be understood that the discussion applies equally to double-sided, multi-layer PCBs made in accordance with the present invention. In the case of a double-sided PCB, the board can be flipped when working on opposite sides, or pick and place means can be provided on both sides of the PCB supported at its edges to allow simultaneous or nearly simultaneous work on both sides. Position and install components.

Figure 13a shows a PCB assembly 1300, which includes a PCB substrate 1302 made of, for example, FR4 or flex board, with a plurality of metals (eg, copper) disposed thereon separated by an epoxy layer 1306. Layer 1304. The uppermost epoxy layer is covered by a solder mask 1308 in which are located a plurality of gold (or other metal) connectors 1310 that are electrically coupled to the metal (e.g., copper) Connector 1312. PCB assembly 1300 may be manufactured using the PCB production systems and methods described above.

PCB assembly 1300 also includes a plurality of electronic components 1316a through 1316c. Components 1316a - 1316c may be integrated circuits (ICs) or other electronic components and assembled into PCB assembly 1300 using a pick and place machine or similar system. Specifically, components 1316a-1316c are positioned such that leads associated therewith form electrical connections with connectors 1310, 1312, etc., such as at pads 1314 or elsewhere. Pad 1314 may be deposited by LAD in a manner similar to the deposition of copper traces, solder mask, and/or connectors as described above.

As shown, electronic components 1316a - 1316c may be added to the PCB assembly and/or embedded in the structure at the top or sides of the structure. When added from the side, the electronic components can be electrically connected to the metal layer through connectors as described above, or directly to the metal layer, as is the case with electronic component 1316c in the illustration. Electronic components 1316b may also be enclosed within PCB assembly 1300. Figures 13b to 13f further illustrate aspects of these different processes for electrically connecting electronic components.

In Figure 13b, PCB substrate 1302 has been printed with a metal (eg, copper) layer 1304 and one or more epoxy layers 1306 in the manner discussed above. Metal (eg, copper) connectors 1312 have been printed in vias in the epoxy layer according to the process described above. Connector 1312 has been positioned to accommodate the placement of electronic components. In one embodiment, the structure shown in Figure 13b can be formed by selectively depositing epoxy with a jet so as to leave open areas 1320 for placement of electronic components. Alternatively, the open area 1320 may be created by laser engraving (eg, etching or ablating) the epoxy layer.

Figure 13c shows the next step in preparing the structure to receive the electronic components. A solder mask layer 1308 has been deposited by LAD in the open area 1320 on top of the epoxy layer, and a gold connector 1310 is made in the solder mask layer to provide electrical coupling to the underlying copper connector 1312. Then, as shown in Figure 13d, solder paste 1314 is jet printed onto the gold connector 1310. The solder paste is printed by laser jetting in the manner discussed above using a laser 1330 and a donor substrate 1332 with solder 1334 coated thereon. The electronic component 1316d is then placed in the open area 1320, with the leads of the electronic cloth piece electrically connected to the solder paste area 1314, such as using a conventional pick and place machine, as shown in Figure 13e. The placement of the electronic components in this manner can be observed using one or more imaging stations to ensure proper alignment of the leads with the solder paste location.

Additional electronic components 1316e may be added to the PCB assembly, as shown in Figure 13f. As shown, electrical connections may be made to multiple sides of electronic component 1316d, and in some cases, additional metal (eg, CU) layers, tags, etc. may be added as described above. During the fabrication of this PCB assembly, a support structure 1330 made of resin or other material may be added to provide temporary or permanent support for the layer covering the open area 1320. Support structures can be added via LAD in the same manner as discussed above for printing other layers.

The assembly of PCB structures is not limited to the placement of electronic components. Other structural components may be included in this structure. Figure 13g shows an example where a heat dissipation element 1340 (eg, a metal plate or other thermal conductor) is added by adhering it to an electronic component 1316d through a layer of thermally conductive glue 1342. Thermal paste can be printed via LAD in a manner similar to that used for printing metal layers or connectors, or solder mask or epoxy. The heat dissipation element may be placed via a pick and place machine or, in some cases, may be a printed structure formed via LAD.

The assembly of a PCB structure is also not limited to placing electronic components in a layer arrangement with other elements of the PCB structure. Figure 13h shows electronic component 1316f positioned so that its electrical leads are orthogonal to the plane of PCB substrate 1302 and its overlying metal layers, epoxy layers, and other layers, and that the electrical leads are in contact with the metal layers, The epoxy layer and other layers are electrically connected through metal (eg, Cu) connectors 1352, gold connectors 1354, and solder paste areas 1356 that are printed to accommodate this orientation. As shown, a temporary or permanent support structure 1330 may be printed to serve as a support for the electronic components when placed in this manner. Printing of the various epoxy layers 1350, connectors 1352, 1354, and solder paste 1356 may be accomplished using LAD in the manner discussed above. It may be desirable to hold portions of the epoxy layer in place when printing solder paste, for example so as not to contaminate underlying structures and/or components. Although not shown, the solder mask can be printed if desired.

Figure 13g shows yet another example of a PCB assembly housing embedded electronic components. In this case, coil 1360 is embedded in epoxy layer 1362 . The coil may be placed via a pick and place machine and electrically connected to another electronic component 1316d via metal (eg, copper) connectors 1310", gold connectors 1312", solder joints 1314" that are themselves printed in the manner discussed above Existing parts, or the coil 1360 itself may be printed via LAD, for example, as described in the present assignee's U.S. Patent Application No. 16/946,638, filed June 30, 2020. For example, it may be similar to that discussed above The method for printing metal layers prints coils by spraying metal from a coating or foil on a donor substrate, where the sprayed material is printed in successive layers so as to partially overlap the most recently printed element and thereby define A spiral pattern of coil elements that together form coil 1360. The coil elements may be printed within supporting epoxy 1362 and/or surround a core (not shown), with the epoxy and core (individually or collectively) acting as a scaffold to Maintaining the integrity of the coil in the construction as the coil elements are fused to each other. Alternatively, the coil 1360 may be printed by LAD as a plurality of partially complete circles, each partially complete circle in a corresponding layer, with the pillars being different layers in the corresponding layer Successive partial-complete circles in are interconnected. Columns can be vertical or nearly vertical, and columns between consecutive partial-complete circles in multiple partial-complete circles can be positioned across partial-complete circles. Circumferential staggering. After printing one of the multiple partially complete circles in the corresponding layer, only connecting posts are printed for multiple consecutive metal layers corresponding to the desired post height. Epoxy scaffold elements can be printed in multiple Each partially complete circle is simultaneously printed as part of each corresponding material layer. Embedding the coils in this manner provides an embedded Radio Frequency Identification (RFID) tag within the PCB assembly.

Figures 14a-14d illustrate aspects of a PCB production cycle where laser-assisted deposition or another laser-based printing process is used for some aspects of PCB manufacturing. In Figure 14a, metal layers (eg, Cu) 1404, 1406 are printed on both sides of a PCB substrate 1402 using LAD or another laser-based printing process as described above. In Figure 14b, the double-sided PCB from Figure 14a is stacked with a similarly fabricated double-sided PCB consisting of metal layers (eg, Cu) 1412, 1414 printed on both sides of a PCB substrate 1410, where two The double sided PCB has a prepreg layer 1416 between them. The prepreg layer 1416 may be a conventional resin-based prepreg (and may be made of the same material as the PCB core substrate), and the stacking process may be performed by conventional means used in the PCB manufacturing industry. The result is component 1420.

As shown in Figure 4c, the stacking process can be repeated with additional double-sided PCBs 1430, 1440, etc., each time including a prepreg layer 1450 between the new double-sided PCB and the previous assembly. When an assembly includes two or more double-sided PCBs with interleaved prepregs, as shown, the assembly is subjected to a lamination process using a conventional hot press process and photosensitive dry resist. The result is a multi-board stack of 1460. Then, as shown in Figure 4d, solder mask 1470 can be printed on each side of the multi-board stack using LAD or another laser-based printing process as described above. Although not shown in detail, gold, silver or other pads and solders and labels can also be printed on each side of the multi-board stack using LAD or another laser-based printing process as described above. Drilling of PCBs and/or post-drilling copper plating can be performed using conventional processes used for such activities.

Although not shown in detail, it will be understood that the various components of the printing systems described herein operate under the control of one or more controllers, which are preferably machine-readable media stored on a tangible machine-readable medium. A processor-based controller that operates under the instructions of executable instructions. Such controllers may include a microprocessor and memory communicatively coupled to each other through a bus or other communication mechanism for transferring information. Memory may include program storage memory, such as read only memory (ROM) or other static storage devices, and dynamic memory, such as random access memory (RAM) or other dynamic storage devices, and each may be coupled to the bus to provide and Stores information and instructions to be executed by the microprocessor. Dynamic memory can also be used to store temporary variables or other intermediate information while the microprocessor is executing instructions. Alternatively or in addition, a storage device such as solid state memory, magnetic or optical disks may be provided and coupled to the bus for storing information and instructions. The controller may also include a display for displaying information to a user, as well as various input devices, including alphanumeric keyboards and cursor control devices such as a mouse and/or trackpad, as part of the user interface of the printing system. Additionally, one or more communication interfaces may be included to provide bidirectional data communication to and from the printing system. For example, network interfaces including wired and/or wireless modems may be used to provide such communications.

Implementation:

1. A method of manufacturing a printed circuit board (PCB) assembly, comprising depositing a metal layer on a PCB substrate by laser assisted deposition (LAD), wherein metal droplets are ejected from a donor substrate by using a laser onto the PCB substrate and/or sprayed into one or more holes in the PCB substrate to form a metal layer on the PCB substrate. The metal layer is then dried and sintered. Spraying, drying and sintering are repeated until the metal layer reaches the desired level. thickness; and forming at least one passivation layer over the metal layer.

2. The method of manufacturing a PCB assembly according to Embodiment 1, further comprising: ablating the metal layer if the metal layer exceeds a desired thickness.

3. A method of manufacturing a PCB assembly according to any one of the preceding embodiments, wherein the ablation is performed using a laser for ejecting metal droplets from the donor substrate.

4. The method of manufacturing a PCB assembly according to any one of the preceding embodiments, wherein the passivation layer includes one of the following: a ring deposited or coated on the metal layer using a roller or doctor blade An oxy resin layer, or an epoxy resin layer printed on the metal layer via LAD from an epoxy resin coating on the donor substrate.

5. The method of manufacturing a PCB assembly according to any one of the preceding embodiments, further comprising: printing an additional metal layer on the epoxy resin layer by LAD.

6. A method of manufacturing a PCB assembly as in any one of the preceding embodiments, wherein the metal layer includes a first metal trace and the epoxy layer includes at least a first portion of epoxy covering at least a first portion of the first metal trace. resin, and the additional metal layer includes a second metal trace having at least a portion of the epoxy layer disposed over a first portion covering the first portion of the first metal trace.

7. The method of manufacturing a PCB assembly according to any one of the preceding embodiments, further comprising: curing the epoxy resin layer by hot air and/or infrared (IR) radiation.

8. The method of manufacturing a PCB assembly according to any one of the preceding embodiments, wherein the core of the PCB substrate is formed in the first side of the PCB substrate by drilling or laser engraving the first side of the PCB substrate One or more holes, but the one or more holes do not pass through the entire thickness of the PCB substrate, form a metal layer in the one or more holes from the first side of the PCB substrate by LAD, and then flip the PCB substrate bottom and complete one or more holes through the thickness of the PCB substrate by drilling or laser engraving through the second side of the PCB substrate, and pass the LAD by drilling or laser engraving through the second side of the PCB substrate. Both sides are metalized while the remainder of the exposed hole or holes is exposed.

9. The method of manufacturing a PCB assembly according to any one of the preceding embodiments, further comprising: printing a solder mask over at least one passivation layer and any intervening layers and/or components of the PCB assembly, the solder mask The layers are printed via LAD.

10. The method of manufacturing a PCB assembly according to any one of the preceding embodiments, further comprising: printing a label on top of the solder mask by LAD.

11. The method of manufacturing a PCB assembly according to any one of the preceding embodiments, further comprising: printing metal connectors in holes in the solder mask by LAD.

12. The method of manufacturing a PCB assembly as in any one of the preceding embodiments, further comprising printing metal connectors in holes in the epoxy layer by LAD.

13. A method of manufacturing a printed circuit board (PCB) assembly, comprising printing metal onto an epoxy laminate by laser-assisted deposition (LAD), the metal being deposited as droplets from a donor substrate Metal coatings or foils are laser sprayed into the channels and/or holes created in the epoxy laminate by laser engraving; and the epoxy laminate is subsequently attached to the PCB by heat pressing A substrate or a previously formed epoxy layer disposed over a PCB substrate to form at least a portion of the PCB assembly, with injection into the channels and/or the holes of the epoxy laminate The metal is between the PCB substrate and the upper surface of the epoxy laminate in the portion of the PCB assembly.

14. The method of manufacturing a PCB assembly of embodiment 13, further comprising: printing a solder mask layer over an upper surface of the epoxy laminate and any intervening layers and/or components of the PCB assembly, the solder mask layer The layers are printed via LAD.

15. The method of manufacturing a PCB assembly according to any one of embodiments 13 or 14, further comprising: printing a label on the solder mask layer by LAD.

16. The method of manufacturing a PCB assembly according to any one of embodiments 13 to 15, further comprising: printing metal connectors in the holes of the solder mask by LAD.

17. A system for manufacturing a printed circuit board (PCB) assembly, comprising a substrate holder configured to hold a PCB substrate and translatable between a plurality of processing stations, the processing stations including: a printing station , the printing station is configured to do so by individually ejecting a respective one of the one or more materials from a respective donor substrate having a respective one or more materials coated or otherwise disposed thereon. Laser-assisted deposition (LAD) of one or more materials; a curing station configured to cure the material deposited in the material by heat, infrared (IR) radiation, or ultraviolet (UV) radiation. material on the PCB substrate; and a drilling station configured to drill in the PCB substrate and/or a layer of the material disposed on the PCB substrate or Engraving vias and/or vias.

18. The system for manufacturing a PCB assembly of embodiment 17, wherein the printing station is further configured to print additional layers of the material on the PCB substrate and/or the PCB assembly. The corresponding materials are subjected to laser sintering and/or laser ablation.

19. The system for manufacturing a PCB assembly of any one of embodiments 17 or 18, wherein the materials include copper and gold pastes, epoxy resin, and solder mask materials.

20. The system for manufacturing a PCB assembly of any one of embodiments 17 to 19, further comprising a device configured to flip the PCB substrate to allow the printing station, the curing station, and/or the drilling station to access the PCB substrate. Two side units.

21. A method for manufacturing a printed circuit board PCB assembly, comprising: drilling or laser engraving one or more through holes in a PCB substrate from a first side of the PCB substrate, the through holes not extending through through the entire thickness of the PCB substrate; a metal slurry is deposited over at least a first portion of the PCB substrate and into one or more vias to a first thickness by laser-assisted deposition (LAD) by using An incident laser beam is performed by ejecting a small volume of metal slurry from a donor film on a first carrier substrate onto the PCB substrate and into one or more vias, solidifying the deposit onto at least a first portion of the PCB substrate and enter the metal paste in one or more vias, and use the same laser used to deposit the metal paste to sinter the deposited and solidified metal paste, and repeat the deposition, solidification and sintering of the metal paste, thereby lining the PCB Form a continuous thickness of metal paste on the substrate and in one or more through holes until the desired thickness of the metal paste on the PCB substrate and in one or more through holes is reached; by LAD on the PCB substrate and one or more through holes A passivation layer is printed on a desired thickness of metal paste in a plurality of vias, the printing being performed by ejecting a small volume of epoxy from a second carrier substrate using the same laser used to deposit the metal paste. , and solidifying the passivation layer; and forming a solder mask over the passivation layer by LAD by spraying a small volume of solder mask from the third carrier substrate using the same laser used to deposit the metal slurry. material to perform, and cure the solder mask.

22. The method of manufacturing a PCB assembly of embodiment 22, wherein heat or ultraviolet (UV) radiation is used to cure the solder mask.

23. The method of manufacturing a PCB assembly of embodiment 21 or 22, wherein heat or infrared (IR) radiation is used to cure the passivation layer.

24. The method of manufacturing a PCB assembly of any one of embodiments 21 to 23, wherein heat or infrared (IR) radiation is used to cure the metal paste.

25. The method of manufacturing a PCB assembly of any one of embodiments 21 to 24, wherein the PCB substrate is moved between drilling, deposition, printing and forming processes on a platform that can be used for drilling, Translation between locations where deposition, printing, and formation processes occur.

26. The method of manufacturing a PCB assembly according to any one of embodiments 21 to 25, wherein the processes of depositing metal slurry and printing a passivation layer are performed multiple times before forming the solder resist to produce a layer of the PCB substrate with a resist layer. PCB assemblies with multiple metal slurry layers and epoxy layers between solder joints.

27. The method of manufacturing a PCB assembly of any one of embodiments 21 to 26, further comprising forming a first metal electrical connector for the electronic component within the passivation layer prior to forming the solder mask.

28. The method of manufacturing a PCB assembly of any one of embodiments 21 to 27, further comprising forming a second metal electrical connector for the electronic component within the solder mask.

29. The method of manufacturing a PCB assembly of any one of embodiments 21 to 28, wherein the first metallic electrical connector is formed of a different metal than the second metallic electrical connector.

30. The method of manufacturing a PCB assembly of any one of embodiments 21 to 29, further comprising attaching the electronic component to the second metal electrical connector via one or more solder points.

31. The method of manufacturing a PCB assembly of any one of embodiments 21 to 30, further comprising forming one or more additional passivation layers and/or solder mask layers over the electronic components.

32. The method of manufacturing a PCB assembly of any one of embodiments 21 to 31, further comprising printing one or more support structures for the electronic components by LAD prior to attaching the electronic components.

33. The method of manufacturing a PCB assembly of any one of embodiments 21 to 32, wherein the desired thickness of the metal paste on the PCB substrate forms at least a first metal trace, and the passivation layer includes covering the first metal At least a first portion of the trace corresponds to the first portion, and further includes printing a second metal trace over the first portion of the passivation layer.

34. The method of manufacturing a PCB assembly as in any one of embodiments 21 to 33, wherein a LAD is used to print the second metal trace.

Claims (15)

1. A method of manufacturing a printed circuit board (PCB) assembly, comprising depositing a metal layer on a PCB substrate by laser assisted deposition (LAD), wherein metal droplets are ejected from a donor substrate by using a laser onto the PCB substrate and/or sprayed into one or more holes in the PCB substrate to form a metal layer on the PCB substrate, followed by drying and sintering the metal layer, the spraying , the drying and the sintering are repeated until the metal layer reaches a desired thickness; and at least one passivation layer is formed on the metal layer. 2. The method of manufacturing a PCB assembly of claim 1, further comprising ablating the metal layer if the metal layer exceeds the desired thickness. 3. A method of manufacturing a PCB assembly according to any one of the preceding claims, wherein said ablation is performed using said laser for ejecting said metal droplets from said donor substrate. 4. A method of manufacturing a PCB assembly according to any one of the preceding claims, wherein the passivation layer comprises one of: a ring deposited or coated on the metal layer using a roller or doctor blade An oxy resin layer, or an epoxy resin layer printed on the metal layer via LAD from an epoxy resin coating on the donor substrate. 5. A method of manufacturing a PCB assembly as claimed in any one of the preceding claims, further comprising printing an additional metal layer over the epoxy layer via LAD. 6. A method of manufacturing a PCB assembly as claimed in any one of the preceding claims, wherein the metal layer includes a first metal trace and the epoxy layer includes at least a first portion covering the first metal trace. at least a first portion of epoxy, and the additional metal layer includes a second metal trace having the first metal trace disposed overlying the epoxy layer. at least a portion of said first portion. 7. A method of manufacturing a PCB assembly as claimed in any one of the preceding claims, further comprising curing the epoxy resin layer by hot air and/or infrared (IR) radiation. 8. A method of manufacturing a PCB assembly according to any one of the preceding claims, wherein the first side of the PCB substrate is formed by drilling or laser engraving the first side of the substrate. The one or more holes in the PCB substrate are formed in the PCB substrate, but the one or more holes do not pass through the entire thickness of the PCB substrate, from the first portion of the PCB substrate through the LAD The metal layer is formed sideways in the one or more holes, then the PCB substrate is turned over and all work through the PCB substrate is accomplished by drilling or laser engraving through the second side of the PCB substrate. the thickness of the one or more holes, and the remaining portion of the one or more holes exposed by the drilling or the laser engraving through the second side of the PCB substrate is metalized by the LAD change. 9. A method of manufacturing a PCB assembly as claimed in any one of the preceding claims, further comprising printing a solder mask over the at least one passivation layer and any intervening layers and/or components of the PCB assembly, The solder mask layer is printed by LAD. 10. A method of manufacturing a PCB assembly as claimed in any one of the preceding claims, further comprising printing a label by LAD over the solder mask. 11. A method of manufacturing a PCB assembly as claimed in any one of the preceding claims, further comprising printing metal connectors in holes in the solder mask via LAD. 12. A method of manufacturing a PCB assembly as claimed in any one of the preceding claims, further comprising printing metal connectors in holes in the epoxy layer via LAD. 13. A system for manufacturing a printed circuit board (PCB) assembly, comprising a substrate holder configured to hold a PCB substrate and translatable between a plurality of processing stations, the processing stations including: a printing station, The printing station is configured to perform by individually ejecting the respective ones of the one or more materials from respective donor substrates having the respective ones of the materials coated or otherwise disposed thereon Laser-assisted deposition (LAD) of the one or more materials; a curing station configured to cure the material deposited in the material by heat, infrared (IR) radiation, or ultraviolet (UV) radiation. material on the PCB substrate; and a drilling station configured to drill in the PCB substrate and/or in a layer of the material disposed on the PCB substrate. Creating or engraving vias and/or vias, where the materials include copper and gold pastes, epoxy resins, and solder mask materials. 14. The system for manufacturing a PCB assembly as claimed in claim 13, wherein the printing station is further configured for additional printing of the material on the PCB substrate and/or the PCB assembly. The corresponding material on the layer is laser sintering and/or laser ablation. 15. The system for manufacturing a PCB assembly of any one of claims 13 and 14, further comprising being configured to flip the PCB substrate to allow the printing station, the curing station and/or the Drilling stations are located close to both sides of the PCB substrate.