CN1275772C - fluid ejection device - Google Patents

Abstract

The present invention provides a fluid ejection device, including: a plurality of orifices formed on the fluid ejection device for ejecting fluid from the print head; a plurality of bubble generators corresponding to the ejection holes, for generating bubbles in the fluid and ejecting the fluid through the ejection holes; a plurality of transistors, wherein the transistors are electrically connected to the bubble generator for turning on and off the bubble generator; a plurality of power pads for providing power to one end of a set of bubble generators; a plurality of address pads corresponding to each of the bubble generators for selecting one of the bubble generators in the set of bubble generators; and a plurality of ground pads for providing a ground connection to the other end of the set of bubble generators, wherein the path formed by the power pad, the metal line electrically connected to the power pad, the bubble generators, the transistors, the metal line electrically connected to the ground pad, and the ground pad is a U-shaped path.

Description

fluid ejection device

The present invention is a divisional application of the original invention patent application (application number: 01143335.3, application date: December 20, 2001, invention name: fluid ejection head structure and manufacturing method thereof).

technical field

The invention relates to a structure of a fluid ejection head and a manufacturing method thereof, in particular to a structure of a fluid ejection head utilizing electric force line layout between two rows of bubble generators and a manufacturing method thereof.

Background technique

At present, fluid ejection devices have been widely used in equipment such as inkjet heads of inkjet printers, and with the continuous improvement of reliability (reliability) of fluid ejection devices, the significant reduction in cost, and the ability to provide high frequency ) and the development of high-quality droplet ejection with high spatial resolution, fluid ejection devices are gradually having many other possible applications, such as: fuel injection system (fuel injection system), cell sorting (cell sorting), medicine Release system (drugdelivery system), jet printing lithography (print lithography) and micro jet propulsion system (micro jet propulsion system), etc.

In today's products, there are not many types of fluid ejection devices capable of individually ejecting liquid droplets of uniform shape, and one of the most successful designs is the method of ejecting liquid droplets using thermally driven bubbles. Because of its simple design and low cost, it is also the most common in use.

For example, in the existing inkjet head structure, in US Pat. No. 5,774,148, a method (center feed) of supplying ink from an intermediate manifold has been mentioned. The structure of the inkjet head is usually sand blasted, laser cut or chemically etched to penetrate the chip, and then the ink is supplied by the middle manifold.

However, using this method not only requires a relatively large chip size, but also the excavated part of the chip cannot be used in any way, which is very uneconomical.

Contents of the invention

The purpose of the present invention is to provide a fluid ejection head structure and its manufacturing method, which can reduce the required chip size and improve economic benefits by increasing the integration of circuit layout.

The purpose of the present invention is achieved in that a fluid ejection device print head is provided, comprising:

a plurality of orifices formed on said fluid ejection device printhead for ejecting ink fluid from said printhead;

A plurality of bubble generators, corresponding to the nozzle holes, are used to generate bubbles in the ink fluid and eject the ink fluid through the corresponding nozzle holes;

a plurality of transistors, wherein the transistors are electrically connected to corresponding bubble generators for turning on and off the bubble generators;

a plurality of power pads for providing power to one end of a set of bubble generators;

a plurality of address pads corresponding to each of the bubble generators for selecting a bubble generator in the set of bubble generators; and

a plurality of ground pads to provide a ground connection for the other end of the set of bubble generators,

Wherein, the power pad, the metal wire electrically connected to the power pad, the bubble generator, the corresponding transistor, the metal wire electrically connected to the ground pad, and the ground pad The path formed by the pads is a U-shaped path.

In addition, the present invention also provides a fluid ejection head structure, the fluid ejection head structure includes: a substrate; a manifold formed in the substrate; at least two rows of fluid chambers, each of which is connected to the fluid chamber a manifold located on both sides of the manifold, used to allow a fluid to flow from the manifold to the fluid chamber; at least one bubble generator formed on the substrate and located in the corresponding fluid chamber; and A conductive circuit is located on the surface of the substrate above the manifold, and part of the conductive circuit is located between the at least two rows of fluid chambers for driving the bubble generator.

The present invention also provides a method for manufacturing a fluid ejection head, which includes the following steps: providing a substrate; forming at least one bubble generator on the substrate; forming a manifold located in the substrate; forming at least two rows of fluid chambers, and each of the fluid chambers is connected to the manifold and located on both sides of the manifold, for allowing a fluid to flow from the manifold into the fluid chamber; and the manifold above the manifold A conductive circuit is formed on the surface of the substrate, and part of the conductive circuit is located between the at least two rows of fluid chambers for driving the bubble generator.

Because the structure of the fluid ejection head provided by the present invention can achieve the effect of smooth ink supply without etching through the entire chip, and it is better at using the space above the manifold for circuit layout, so the present invention can not only effectively enhance the manifold The strength of the structural layer above the tube can greatly reduce the size of the chip, expand the number of nozzles, and increase the printing speed.

Description of drawings

Fig. 1 is the structural sectional view of inkjet head structure of the present invention;

Fig. 2 is a cross-sectional schematic diagram of an embodiment of the present invention;

Figure 3 is a top view of the fluid ejection head of the present invention;

Fig. 4 is a partially enlarged view of the fluid ejection head chip of the present invention;

Fig. 5 is a schematic diagram of a matrix drive circuit of the fluid ejection head of the present invention;

6 to 8 are schematic diagrams of the manufacturing process of the fluid ejection head of the present invention.

Detailed ways

Please refer to FIG. 1 , which is a cross-sectional view of the structure of the fluid ejection head of the present invention. The fluid ejection head of the present invention is a fluid ejection device with a virtual valve. As shown in Figure 1, the bubble generator includes two bubble generating components, respectively a first heating assembly 14a and a second heating assembly 14b, which surround the nozzle hole (nozzle) 12 and are separated by two heating assemblies 14a, 14b. The difference, such as the difference in resistance value, can cause two bubbles to be generated successively when the two heating elements 14a, 14b are heated. First, a first air bubble (not shown) is formed at the nozzle hole 12 than at the first heating element 14a close to the manifold 11, and the first bubble will isolate the manifold 11 from the nozzle hole 12 to generate similar gas. The function of the valve is to reduce the effect of cross talk with the adjacent fluid chamber 16, and then a second air bubble (not shown) will be generated near the second heating element 14b, so that the second air bubble pushes A fluid (not shown) in the fluid chamber 16 causes the fluid to be ejected from the orifice 12 . Finally, the second bubble will combine with the first bubble, and the combination of the two bubbles can reduce the generation of satellite droplets.

Because the structure of the fluid ejection head of the present invention does not need to etch through the entire chip, it can meet the requirement of ejecting liquid smoothly, so based on this structure, the present invention can carry out the layout of power lines (power lines) above the manifold 11, and at the same time Strengthen the strength of the structural layer above the manifold 11. In addition, for the convenience of explanation, the fluid ejection head of the present invention will be described below using an inkjet head as an embodiment.

Please refer to FIG. 2. FIG. 2 is a cross-sectional view of the entire chip of the present invention, wherein a low-temperature oxide layer 18 is deposited on the first heating element 14a and the second heating element 14b as a protective layer, and holes are opened in designated areas ( via) to allow the metal layer 13 to flow into the upper surface of the heaters 14a, 14b through the hole, so as to achieve the purpose of electrically connecting the metal conductive layer 13 and the heaters 14a, 14b.

Similarly, the drain 68 and source 66 of the MOSFET (Metal Oxide Semiconductor Field Effect Transistor) component 15 are also electrically connected to the heaters 14a, 14b and the ground 20 through the metal layer 13 . Therefore, when the grid (gate) 64 of the MOSFET assembly 15 is opened, the pad (pad) made of the metal layer 13 will send the voltage signal supplied from the outside to the inkjet head. The liner enters, first passes through the metal layer 13 to the first heater 14a and the second heater 14b, then passes through the drain of the MOSFET component 15 to the source, and then flows to the ground terminal 20 to complete a heating action. At this time, since the ink in the fluid chamber 16 (ie, the ink ejection chamber of the inkjet head) is heated, two bubbles are generated to push the ink drop out through the nozzle hole 12 . Wherein, different nozzle holes 12 can be respectively controlled to eject ink droplets according to the amount of required printing data. In addition, the material of the metal layer 13 is selected from the group consisting of Aluminum (Aluminum), Gold (Gold), Copper (Copper), Tungsten (Tungsten) and Alloys of Al-Si-Cu. .

Please refer to FIG. 3 and FIG. 4, FIG. 3 is a top view of the inkjet head of the present invention. In this embodiment, it is divided into 16 P groups (including P1 to P16), and each P group includes 22 addressing (Address, A1 to A22), which can be compared with the matrix driving circuit diagram in Figure 5, a The logic circuit or the microprocessor 32 will send a selection signal to the power line driver (power driver) 34 and the address line driver (address driver) 35 according to the data to be printed, to control which addressing (A1 to A22) will be opened And to which P group (P1 to P16) the power is supplied. For example, if power is supplied to P1 and A22 is turned on, the heaters 14a and 14b of A22 in the P1 group will complete the heating and ink ejection operations according to the set time.

FIG. 4 is a partially enlarged view of area B (dotted line) in FIG. 3 . As shown in Figure 4, it can be clearly seen that two rows of nozzle holes 12 are arranged in the middle of the chip. The right side of the chip AA' includes eight groups of injection holes (P1 to P8), and the left side also includes eight groups of injection holes (P9 to P16). And use the top of the manifold 11, the central area between the two rows of spray holes 12 to carry out the layout of the power line (power line) 19, on the right side of the dividing line A-A', 8 metal lines (metal lines, P1 to P8), and connect to the I/Opads on the right. Similarly, 8 metal lines (metal lines, P9 to P16) are arranged on the left side of the dividing line A-A', and are connected to the left I/O pads (not shown in the figure).

Each group of pads P to pad G of the present invention adopts a U-shaped driving circuit layout method, such as the driving circuit layout method from pad P1 to pad G1 (as shown by the dotted line), and the circuit connections are different from each other. Crossover, and only one layer of metal layer 13 is used to complete the connection of power line 19 to heaters 14a, 14b, then to MOSFET component 15, and finally to ground pad G. In addition, 11 horizontal metal wires 22 are arranged on the upper and lower sides of the MOSFET assembly 15, and the horizontal metal wires 22 are connected to the pad A, and are used to transmit the data input by the address line driver 35 to each MOSFET assembly 15 to determine which nozzle hole 12 ejects the ink, and arranges 11 vertical polysilicon lines (polysilicon lines) 23 on the left and right sides of the MOSFET assembly 15 (i.e. near the two ends of the chip), a total of 22 polysilicon lines 23, and between the horizontal metal lines 22 and the vertical lines The part of polysilicon line 23 to be electrically connected is marked with a contact layer (contact layer) 24 to complete the electrical connection, and the effect of polysilicon line 23 is to connect the horizontal metal line 22 at the upper and lower ends of the chip. The heating element of P16 needs to pass through the vertical polysilicon line 23 to the horizontal metal line 22 below, so as to be connected to the heater of P16 to achieve the function of inkjet, and its operating principle will be described in detail later.

The fabrication method of the fluid ejection head structure of the present invention is further described in detail as follows. Please refer to FIG. 6 to FIG. 8 . FIG. 6 to FIG. 8 are schematic diagrams of the manufacturing process of the fluid ejection head structure of the present invention. First, a field oxide layer (Fieldoxide) 62 is formed on a silicon chip substrate 60 by local oxidation. Then perform a boron ion implantation (Blanket boron implant) to adjust the initial voltage (Threshold voltage) of the driving circuit, and then form a polysilicon gate (Polysilicon gate) 64 in the field oxide layer 62, wherein the polysilicon gate 64 is formed At the same time, 22 vertical polysilicon lines 23 as mentioned above are formed on both sides of the chip close to the edge to serve as wires. Afterwards, ion implantation is performed to form a source 66 and a drain 68 on both sides of the gate 64 to complete the MOSFET device 15 . Then deposit a low stress layer (Low stress layer) 72, such as silicon nitride (SiNx) material, as the upper layer of the fluid chamber 16, as shown in FIG. 6 .

Please refer to FIG. 7, next, use an etchant potassium hydroxide (KOH) to etch from the backside of the substrate 60 to form a manifold 11, which serves as the main flow channel for the supply fluid to enter, and then part of the field oxide layer 62 is etched with an etchant Hydrofluoric acid (HF) is removed as fluid chamber 16 . Then under precise control of the etching time, another etching with the etching solution potassium hydroxide (KOH) is carried out to increase the depth of the fluid chamber 16, so that the fluid chamber 16 and the manifold 11 are communicated and can be filled. fluid. Special attention should be paid during this etching step, because the convex corner (Convex corner) of the fluid chamber 16 will also be attacked by the etching solution and be etched into a circular arc shape.

Then continue with the heater manufacturing process. Wherein, the heater includes a first heater 14a and a second heater 14b, and the manufacturing process of the heater can be easily completed by those skilled in the art, so it will not be repeated here. In addition, for the first heater 14a and the second heater 14b, the preferred material is aluminum tantalum alloy (Alloys of tantalum and aluminum), and other materials such as platinum (Platinum), hafnium boride (HfB2) etc. can achieve the same effect. In addition, in order to protect the first heater 14a and the second heater 14b and to isolate the one or more MOSFET components 15, on the entire substrate 60, including the gate 64, the source 66, the drain 68 and the field oxide layer 62 A low temperature oxide layer 74 is then deposited as a protection layer.

Next, a conductive layer (Conductivelayer) 13 is formed on the first heater 14a and the second heater 14b, which is used as a first conductive line to connect the first heater 14a, the second heater 14b and the driving circuit. functional components. Wherein, the drive circuit is used to independently transmit a signal to individual heaters (the first heater 14a and the second heater 14b), and is used to drive more than one pair of heaters (the first heater 14a and the second heater 14b). The heater 14b), so that a small number of circuit components and connecting lines can be used to achieve the same effect of the control circuit. In an embodiment of the present invention, the preferred material of the conductive layer 13 is such as Al-Si-Cu alloy (Alloys of Al-Si-Cu), aluminum (Aluminum), copper (Copper), gold (Gold) or tungsten (Tungsten) and other metal materials. Then deposit a low temperature oxide layer 76 on the conductive layer 13 as a protection layer.

Finally, referring to FIG. 8 , an injection hole 12 is formed between the first heater 14 a and the second heater 14 b. So far, an array of fluid ejection devices integrally formed and having a driving circuit can be formed. It can be seen from the above description that the present invention not only integrates the driving circuit and the heater on the same substrate, but also completes the structure of the whole micro-spray head without attaching a nozzle plate.

Then describe its action principle in detail as follows: please refer to Fig. 4 and Fig. 5, when performing inkjet printing, the logic circuit or microprocessor 32 will decide which nozzle hole to eject ink according to the data to be printed, Then a selection signal will be sent to the power line driver (power driver) 34 and the address line driver (address driver) 35 to enable the corresponding addressing (A1 to A22) and power supply to the corresponding P group (P1 to P16), Afterwards, the current flows through the heaters 14a, 14b to heat the fluid to generate air bubbles to perform an ink ejection action. For example: if the nozzle hole 12a at the A1P1 place is to be ejected, a voltage signal must be sent to the gate 64 of the MOSFET assembly 15 via the input-output pad A1 to open the switch, and then the switch will be opened by The input and output pad P1 provides a voltage signal to generate current, and the current will flow through the heaters 14a, 14b to heat the ink to generate air bubbles, then flow through the drain 68 of the MOSFET component 15 to the source 66, and finally flow To the ground terminal 20, so far, the action of ejecting an ink drop is completed.

Although the structure of the above-mentioned inkjet head is only described with the structure of a monochrome printer, the application of the present invention is not limited to the monochrome inkjet printer, and the present invention is also applicable to the structure of a color or multicolor inkjet head. In addition, the fluid injection device of the present invention also has many other possible applications, such as: fuel injection system, cell classification, drug release system, jet printing lithography technology, micro-jet propulsion system, etc., not limited to inkjet printing.

Therefore, the structure of the fluid ejection head provided by the present invention and its manufacturing method perform the circuit layout of the conductive layer of the entire chip at the position between the two rows of bubble generators above the manifold, which has the following effects:

(1) Since the ink supply method does not use the method of punching through the entire chip, the circuit layout can be carried out above the manifold, which will save the size of the entire chip and increase the chip cutting amount of the entire wafer (wafer);

(2) Winding layout on the structural layer above the manifold can effectively improve the strength of this structural layer; and

(3) The area occupied by the circuit layout can be saved through this method of improving the integration degree of the circuit layout, that is, under the same chip area, more nozzle holes can be set to increase the printing speed.

The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the claims of the present invention should fall within the scope of the patent of the present invention.

Claims (11)

1. fluid ejection apparatus comprises:

A plurality of spray orifices are formed on the described fluid ejection apparatus, are used for from described printhead ejecting fluid;

A plurality of bubble generators, corresponding with described spray orifice, be used for producing bubble at fluid, and by corresponding spray orifice ejecting fluid;

A plurality of transistors, wherein said transistor are electrically connected on the corresponding bubble generator, are used for opening and closing bubble generator;

A plurality of electric power liners are used for electric power is provided to an end of one group of bubble generator;

A plurality of addresses liner, described address liner is corresponding with in the described bubble generator each, is used for selecting in this group bubble generator a bubble generator; And

A plurality of grounding gaskets are used to the other end of this group bubble generator that ground connection connection is provided,

Wherein, by described electric power liner, be electrically connected to the metal wire on the described electric power liner, described bubble generator, corresponding crystal pipe, the metal wire and the formed path of described grounding gaskets that are electrically connected on the described grounding gaskets be the path of a U-shaped.

2. fluid ejection apparatus as claimed in claim 1 wherein, forms the adjacent grounding gaskets of many groups between electric power liner and address liner.

3. fluid ejection apparatus as claimed in claim 1 or 2, wherein, each electric power liner and grounding gaskets are electrically connected by the metal wire that is formed in the fluid ejection apparatus.

4. fluid ejection apparatus as claimed in claim 2, wherein, each in described electric power liner, described address liner and the described grounding gaskets all is electrically connected in the described fluid ejection apparatus on the formed metal wire.

5. fluid ejection apparatus as claimed in claim 4, wherein, each bubble generator and corresponding crystal pipe are electrically connected on the polysilicon lines that forms in the described fluid ejection apparatus.

6. fluid ejection apparatus as claimed in claim 5, wherein, the metal wire that is electrically connected on the liner of described address is connected on the polysilicon lines by crossing hole connector, and described polysilicon lines is electrically connected on bubble generator and the corresponding crystal pipe.

7. fluid ejection apparatus as claimed in claim 2, wherein, described bubble generator comprises heater, described heater is used for adding hot fluid and forms bubble in fluid.

8. fluid ejection apparatus as claimed in claim 2, wherein, with the corresponding transistor of described bubble generator be gold oxygen semiconductor field effect transistor with polysilicon gate.

9. fluid ejection apparatus as claimed in claim 2 wherein, forms one group of adjacent electric power liner in the center of fluid ejection apparatus one side, and the adjacent grounding gaskets of described many groups is formed on the either side of the adjacent electric power liner of this group.

10. fluid ejection apparatus as claimed in claim 9 wherein, forms the adjacent address liner of many groups on each outside of the adjacent grounding gaskets of described many groups.

11. fluid ejection apparatus as claimed in claim 10, wherein, described electric power liner, described grounding gaskets and described address liner are formed on the relative both sides of fluid ejection apparatus, and form a plurality of spray orifices between them.

Images