JP7650745B2 - Apparatus, method, and program for verifying mountability of electronic components, and recording medium - Google Patents

Description

The present disclosure relates to an electronic component mountability confirmation device, a mountability confirmation method, a mountability confirmation program, and a recording medium for predicting and determining whether a surface-mount electronic component can be correctly mounted on a printed circuit board (hereinafter referred to as a board) before the electronic component is actually mounted on the board.

Generally, CAD (computer-aided design) systems define surface-mount electronic components as a body and electrodes, and have three-dimensional data for the electronic components consisting of dimensional information that determines the shape of the electronic components, but do not have three-dimensional data for the board on which the electronic components are mounted, and only have two-dimensional data.

Patent Document 1 shows a joint model generation device that extracts the bottom surface of the electrode of an electronic component and the top surface of the pad, generates a surface connecting the contour lines of the bottom surface and top surface as a side surface, and generates a solder joint model consisting of the side surface, bottom surface, and top surface, because data regarding the shape of the solder that joins the electrodes and pads of an electronic component is not stored in two-dimensional data.

JP 2011-170820 A

In recent years, surface-mount electronic components mounted on substrates have become increasingly smaller, and the influence of the solder paste that connects the electrodes of the electronic components to the electrode pads formed on the surface of the substrate can no longer be ignored when mounting electronic components on a substrate.
As disclosed in Patent Document 1, simply generating a solder joint model does not allow verification of whether an electronic component can be correctly mounted on a board.

The present disclosure has been made in consideration of the above points, and aims to provide an electronic component mountability confirmation device that can predict and determine whether a surface-mount electronic component can be correctly mounted on a board before the electronic component is actually mounted on the board.

The electronic component mountability confirmation device according to the present disclosure is disposed on a substrate on which a surface-mount electronic component is mounted, and includes a model generation unit that generates three-dimensional information representing a three-dimensional solder paste model of the solder paste connecting the electrodes of the electronic component and the electrode pads on the substrate from the planar shape of the electrode pads and solder paste thickness information obtained from the opening shape of a two-dimensional metal mask used to print the solder paste, a model transformation unit that converts the three-dimensional information representing the three-dimensional solder paste model into deformed three-dimensional information representing a deformed solder paste model in which the volume of the solder paste is kept constant and the three-dimensional shape of the solder paste is changed, and a calculation unit that determines whether the relationship between the electrodes of the electronic component and the solder paste based on the deformed three-dimensional information generated by the model transformation unit satisfies a specified range, and issues an error if the specified range is not satisfied.

According to the present disclosure, it is possible to determine whether the relationship between the electrodes of an electronic component and the solder paste based on the three-dimensional deformation information generated by the model deformation unit satisfies a specified range, thereby making it possible to determine whether the electronic component is correctly mounted on the board.

1 is a block diagram showing a configuration example of an electronic component mountability checking device according to a first embodiment; 1 is a cross-sectional view showing an example of a state in which the relationship between the terminal electrodes of a surface-mount electronic component without bottom electrodes and the solder paste is normal in the electronic component mountability confirmation device according to embodiment 1. FIG. FIG. 11 is a cross-sectional view showing an example of a state in which the relationship between the terminal electrodes of a surface-mount electronic component without bottom electrodes and the solder paste is abnormal, causing the electronic component to be tilted relative to the substrate, in the electronic component mountability confirmation device of embodiment 1. 1 is a cross-sectional view showing an example of a state in which the relationship between the bottom electrode of a surface-mount electronic component having a bottom electrode and the solder paste is normal in the electronic component mountability confirmation device according to embodiment 1. FIG. FIG. 1 is a cross-sectional view showing an example of a state in which the relationship between the bottom electrode of a surface-mount electronic component having a bottom electrode and the solder paste is abnormal in an electronic component mounting performance confirmation device of embodiment 1, and the bottom electrode is not electrically connected to the bottom electrode pad. 1 is a diagram illustrating an example of a hardware configuration of an electronic component mountability checking device according to a first embodiment; 5 is a flowchart showing an example of the operation of model generation and model transformation of the electronic component mountability confirmation device according to the first embodiment. 5 is a flowchart showing an example of an operation of checking an error in a surface-mount electronic component without bottom electrodes by the electronic component mountability checking device according to the first embodiment. 6 is a flowchart showing an example of an operation of an error check in the presence of bottom electrodes in the electronic component mountability checking device according to the first embodiment.

Embodiment 1.
First Embodiment An electronic component mountability checking apparatus according to a first embodiment will be described with reference to FIGS.
The electronic component mountability checking device according to the first embodiment is a mountability checking device used in a system that uses CAD to perform a design for mounting electronic components on a printed circuit board.
First, the terms used to describe the electronic component mountability checking device according to the first embodiment will be described.

The electronic components are surface-mount electronic components such as surface-mount semiconductor elements such as SOP (Small Outline Package), QFP (Quad Flat Package), SOJ (Small Outline J-leaded), PLCC (Plastic leaded chip carrier), and BGA (Ball Grid Array) type semiconductor elements, two-terminal electrode chip components such as resistors, capacitors, coils, and diodes, connectors, spacers, and heat dissipation fins.

Among surface mount electronic components, electronic components that do not have bottom electrodes, for example, surface mount electronic components typified by chip components with two terminal electrodes, are hereinafter referred to as first electronic components.
Terminal electrodes (hereinafter sometimes simply referred to as electrodes) of the first electronic component are connected by solder paste to electrode pads formed on the surface of the substrate.

Among surface mount electronic components, electronic components having bottom electrodes, for example, surface mount electronic components typified by surface mount semiconductor elements such as QFP, are hereinafter referred to as second electronic components.
Terminal electrodes (hereinafter sometimes simply referred to as electrodes) of the second electronic component are connected by solder paste to electrode pads formed on the surface of the printed circuit board.

The bottom electrode of the second electronic component is a grounding or heat dissipation electrode formed of a metal integrated with the body on the back surface of the body of the second electronic component, and is connected by solder paste to a bottom electrode pad formed on the surface of the substrate.
The bottom electrode of the second electronic component is also an electrode of the electronic component.
Hereinafter, when the term "electronic component" is used simply, it includes both the first electronic component and the second electronic component.

The solder paste is printed onto the electrode pads and bottom electrode pads using a metal mask formed on the surface of the substrate, and after printing, it is melted by reflow, connecting and bonding the electrode pads facing the electrodes of the electronic component and the bottom electrode pads facing the bottom electrodes of the second electronic component.

Solder paste is composed of a mixture of solder powder and flux in a specified ratio, and when reflowed, it melts and the flux evaporates. As a result, the volume of the solder paste decreases, and the thickness after reflow is smaller than the thickness of the solder paste when it is applied. In other words, the height from the surface of the electrode pad to the surface of the solder paste after reflow is lower than the height from the surface of the electrode pad to the surface of the solder paste when it is applied.

In addition, the time (timing) for the solder paste to melt and the way the molten solder paste spreads during reflow (contact area) may differ for the applied electrode pad and the bottom electrode pad, and electronic components may be attracted to the electrode pad to which the molten solder paste was applied first, or to the electrode pad with a larger contact area.

The symbol print indicates the outline or position of the electronic component printed by a commonly known printing method on the surface of the solder resist formed on the surface of the board directly below the electronic component.

Specifically, a symbol print is a character string or any symbol or design printed on the surface of a board, or a display that represents part or all of the circuit symbol, shape, mounting direction, etc. of an electronic component.
The symbol print has a thickness from the surface of the solder resist formed on the surface of the board.

The board data is three-dimensional data showing the wiring layer (copper foil) that forms the circuit pattern formed on the surface of the board, the electrode pads and bottom electrode pads that are connected to the electrodes of the electronic components, and the solder resist consisting of an insulating film that protects the circuit pattern, as well as two-dimensional data showing the planar shape of the symbol print and metal mask.

The board data regarding the symbol print and metal mask is two-dimensional data indicating a planar shape, and does not include thickness information of the symbol print and metal mask.
The metal mask is used to print and apply the solder paste onto the surfaces of the wiring layer, the electrode pads and the bottom electrode pads.
Therefore, the applied thickness of the solder paste and the printed thickness of the symbol print are not directly or indirectly included in the board data.

Three-dimensional electronic component data is data that determines the shape of an electronic component, defines the electronic component as a body and electrodes, and is three-dimensional dimensional information for the body and electrodes.

The electronic component mountability checking apparatus 1 according to the first embodiment includes a shape calculation apparatus 10 and a design verification apparatus 20, as shown in FIG.
The shape calculation device 10 includes an input unit 11, an electronic component selection unit 12, a model generation unit 13, and a model transformation unit 14.
The design verification device 20 includes a calculation unit 21 and a verification result output file 22 .

The input unit 11 receives input of the board data 2 and the three-dimensional electronic component data 3, as well as input of solder paste thickness information and symbol print thickness information from an external input device (UI: User Interface).
The input unit 11 also serves as a cache memory for temporarily storing input information.

The board data 2 and the three-dimensional electronic component data 3 are stored in a storage medium, and are input to the input unit 11 in a linked manner with the model names of the printed boards and the electronic components, etc.
The solder paste thickness information and the symbol print thickness information are information that the user sets using the external input device 4, and are either entered directly from the keyboard of the external input device 4 or read from information stored in the storage medium of the external input device 4.

The electronic component selection unit 12 selects an electronic component to be verified from a plurality of electronic components mounted on the surface of the printed circuit board, based on the board data 2 and the three-dimensional electronic component data 3 input to the input unit 11. The selection of the electronic component is specified by the linked type name, etc.
For the electronic components selected by the electronic component selection unit 12, the connection state between the electrodes of the electronic components and the electrode pads by the solder paste is verified by the model generation unit 13 and subsequent units.
All of the electronic components mounted on the surface of the printed circuit board are verified in sequence by the model generation unit 13 and subsequent units.

The model generation unit 13 generates, for an electronic component selected by the electronic component selection unit 12, first three-dimensional information indicating a three-dimensional solder paste model of the solder paste connecting the electrodes of the electronic component and the electrode pads, from the planar shape of the electrode pads to which the electrodes of the electronic component are connected and thickness information of the solder paste.
In addition, to avoid complexity, the electrodes of the electronic components refer to the electrodes based on the three-dimensional dimensional information of the electrodes in the three-dimensional electronic component data 3 input to the input unit 11, and are simply referred to as electrodes of the electronic components.

The planar shape of the electrode pads is obtained by the model generating unit 13 from information indicating the opening shape of the metal mask in the board data 2 input to the input unit 11 .
That is, a projection surface of the solder paste onto the substrate is extracted from the opening of the metal mask, and the extracted projection surface is made into the planar shape of the electrode pad.
Therefore, the planar shape of the electrode pad here is slightly smaller than the planar shape of the electrode pad in board data 2.

The solder paste thickness information is set by the external input device 4 and input to the input unit 11 .
The three-dimensional solder paste model is a three-dimensional model of the solder paste when applied to the electrode pads.

The model generation unit 13 generates second three-dimensional information indicating a three-dimensional symbol print model of the symbol print from the planar shape of the symbol print to be printed on the surface of the board for the electronic components selected by the electronic component selection unit 12 and the thickness information of the symbol print.

The planar shape of the symbol print is obtained by the model generating unit 13 from information indicating the planar shape of the symbol print in the board data 2 input to the input unit 11 .
The thickness information of the symbol print is set by the external input device 4 and input to the input unit 11 .

The model transformation unit 14 changes the first three-dimensional information indicating the three-dimensional solder paste model generated by the model generation unit 13 into deformed three-dimensional information indicating a deformed three-dimensional solder paste model in which the volume of the solder paste is kept constant and the three-dimensional shape of the solder paste is changed.
The relationship between the three-dimensional solder paste model and the deformed three-dimensional solder paste model is such that the volume is constant and the height is determined taking into consideration the rate of decrease due to the decrease in volume caused by reflow of the solder paste.

The volume of the solder paste in the three-dimensional solder paste model is the product of the area of the planar shape of the electrode pad obtained from the information indicating the opening shape of the metal mask and the thickness value obtained from the thickness information of the solder paste.

For example, when the mixing ratio of solder powder to flux in the solder paste is 1:0.25, the volumes of the three-dimensional solder paste model and the deformed three-dimensional solder paste model are kept constant, and the height of the deformed three-dimensional solder paste model is 0.8 times the height of the three-dimensional solder paste model.
Furthermore, when the mixing ratio of solder powder to flux in the solder paste is 1:1, the volumes of the three-dimensional solder paste model and the deformed three-dimensional solder paste model are kept constant, and the height of the deformed three-dimensional solder paste model is 0.5 times the height of the three-dimensional solder paste model.

The model transformation unit 14 determines whether the electrodes of the electronic component selected by the electronic component selection unit 12 interfere with, for example contact with, the three-dimensional symbol print model based on the second three-dimensional information generated by the model generation unit 13, and if there is interference, performs a correction to move the position of the electronic component to a position where there is no interference.

The calculation unit 21 in the design verification device 20 determines whether the relationship between the electrodes of the electronic component and the solder paste based on the three-dimensional deformation information generated by the model deformation unit 14 satisfies a specified range, in other words, whether it is inside or outside the specified range, and if it does not satisfy the specified range, it issues an error, stating that the connection between the electrodes of the electronic component and the electrode pads using the solder paste is not good.

The calculation unit 21 determines whether the electronic component has a bottom electrode, i.e., whether the electronic component selected by the electronic component selection unit 12 is a first electronic component (without a bottom electrode) or a second electronic component (with a bottom electrode).

When the calculation unit 21 determines that it is a first electronic component, it determines the relationship between the electrodes of the first electronic component and the solder paste based on the deformed three-dimensional information generated by the model transformation unit 14 as the area ratio of the contact area where the solder paste based on the deformed three-dimensional information comes into contact with the electrodes of the first electronic component to the area of the planar shape of the electrode pad, and compares this area ratio with the first specified range.

In other words, when the electrode of the first electronic component is connected to the electrode pad formed on the substrate by the solder paste based on the deformed three-dimensional information, the area of the surface onto which the solder paste is applied to the electrode pad based on the first three-dimensional information, i.e., the area ratio of the contact area where the solder paste comes into contact with the electrode of the first electronic component to the planar area of the applied solder paste, is determined to be within or outside the first specified range.

The contact area where the solder paste comes into contact with the electrodes of the first electronic component is calculated by the calculation unit 21, which determines the contact angle where the electrodes of the first electronic component come into contact with the solder paste based on the height of the solder paste from the deformed three-dimensional information, the planar shape of the solder paste from the first three-dimensional information, the external shape of the selected first electronic component in the three-dimensional electronic component data 3, the planar shape of the symbol print in the board data 2, and the height of the symbol print set by the external input device 4, and then calculates the contact area from the determined contact angle.

If the area ratio is outside the first specified range, it is determined that the area ratio does not satisfy the first specified range, and it is determined that the first electronic component is connected at an angle to the surface of the board by the solder paste, resulting in an error.
The reason why the first electronic component is inclined with respect to the surface of the substrate is as follows.
In the following description, the first electronic component is a chip component with two terminal electrodes.

In other words, as electronic components become smaller, it becomes necessary to take into consideration the thickness of the symbol print, and the height of the solder paste from the board surface after reflow becomes lower than the height of the symbol print from the board surface, causing the symbol print to interfere with the first electronic component and affect the mounting of the first electronic component on the board, and due to differences in the time (timing) at which the solder paste melts or the way the molten solder paste spreads on both electrodes of the first electronic component, the electronic component is attracted to one of the electrodes, and due to the influence of the height of the symbol print, the first electronic component is tilted to one of the electrodes.

As a result, the other electrode of the first electronic component is left floating relative to the electrode pad, and the other electrode of the first electronic component is not soldered properly to the electrode pad, or in the worst case, is not soldered at all.

The calculation unit 21 assumes that when the height of the solder paste from the surface of the board after reflow is lower than the height of the symbol print from the surface of the board, the first electronic component will be attracted to one of the electrodes and both electrodes will be in asymmetric contact with the solder paste, and determines the contact area of the electrode of the first electronic component in contact with the solder paste and calculates the relationship between the electrode of the first electronic component, the electrode pad, and the solder paste.
An example of this state is shown in FIG.

Furthermore, when the amount of solder paste applied is set so that the height of the solder paste from the surface of the board after reflow is higher than the height of the symbol print from the surface of the board, the calculation unit 21 calculates the relationship between the electrodes of the first electronic component, the electrode pads, and the solder paste, and obtains a result in which the area ratio of the contact areas falls within the first specified range, and the first electronic component is in a state where it is well connected to the surface of the board by the solder paste. An example of this state is shown in Figure 2.

In Figures 2 and 3, Sub is a substrate with multiple wiring layers formed therein, D1 is a first electronic component, e1 and e2 are terminal electrodes of the first electronic component D1, EP1 and EP2 are electrode pads to which the terminal electrodes e1 and e2 of the first electronic component D1 are connected, H1 and H2 are solder paste applied to the electrode pads EP1 and EP2 after reflow, S is a printed symbol print, and R is a solder resist.

In addition, even in the case of a surface-mount type semiconductor element that does not have a bottom electrode as the first electronic component, similarly to a chip component with two terminal electrodes, by determining whether the ratio of the contact area where the solder paste comes into contact with the terminal electrode (lead) of the semiconductor element to the area of the planar shape of the electrode pad is within or outside the first specified range, it is possible to know whether the semiconductor element is connected at an angle to the surface of the board by the solder paste or is connected well.

Even if the area ratio of the contact area of the solder paste to all the electrodes of the first electronic component is calculated to be within the first specified range, some electrodes will not come into contact with the solder paste when actually mounted, particularly in surface-mount semiconductor elements that have many terminal electrodes. Therefore, the calculation unit 21 checks the contact state with the solder paste for all the electrodes of the first semiconductor element using the deformation three-dimensional information.

When the calculation unit 21 determines that it is a second electronic component (with bottom electrodes), in addition to determining the relationship between the electrodes (leads) of the second electronic component and the solder paste based on the three-dimensional deformation information generated by the model deformation unit 14, it also determines the thickness of the solder paste based on the three-dimensional deformation information relative to the distance from the surface of the bottom electrode of the second electronic component to the surface of the bottom electrode pad that the bottom electrode faces (hereinafter referred to as the bottom electrode distance).

If the thickness of the solder paste is shorter than the bottom electrode distance, the calculation unit 21 determines that the thickness of the solder paste relative to the bottom electrode distance does not satisfy the second specified range, and that the bottom electrode of the second electronic component does not contact the solder paste according to the deformed three-dimensional information, resulting in an error.

In addition, even if the thickness of the solder paste is calculated to be longer than the bottom electrode distance, when actually mounted, the bottom electrode may not be properly soldered to the bottom electrode pad with the solder paste, resulting in insufficient joint strength, and the calculation unit 21 also performs the following calculation.

That is, the calculation unit 21 calculates the minimum spatial volume, which is the product of the distance (bottom electrode distance) from the surface of the bottom electrode of the second electronic component to the surface of the bottom electrode pad that the bottom electrode faces, and the planar area of the bottom electrode, and the volume of the solder paste after reflow, which is the product of the thickness of the solder paste based on the deformed three-dimensional information and the planar shape of the solder paste based on the first three-dimensional information, and determines whether the volume ratio of the volume of the solder paste after reflow to the minimum spatial volume satisfies the third specified range, in other words, whether it is inside or outside the third specified range, thereby determining whether the solder paste is applied between the surface of the bottom electrode and the bottom electrode pad without excess or deficiency.

The volume of the solder paste after reflow and the minimum space volume are calculated by the calculation unit 21 from the planar shape of the solder paste based on the first three-dimensional information, the height of the solder paste based on the deformed three-dimensional information, the outer shape of the selected second electronic component in the three-dimensional electronic component data 3, and the planar shape of the metal mask in the board data 2.

If the amount of solder paste applied to the bottom electrode pad facing the bottom electrode of the second electronic component is small relative to the plane area of the bottom electrode, even if the terminal electrode of the second electronic component is soldered correctly to the electrode pad, the bottom electrode of the second electronic component will not be soldered correctly to the bottom electrode pad with the solder paste, resulting in insufficient joint strength, and in the worst case, the bottom electrode and bottom electrode pad will not be soldered at all, causing problems with mounting the second electronic component to the board.

In a surface-mount semiconductor element having a bottom electrode as the second electronic component, FIG. 4 shows an example of a state in which the bottom electrode of the second electronic component is correctly soldered to the bottom electrode pad with solder paste, and FIG. 5 shows an example of a state in which the thickness of the solder paste based on the deformed three-dimensional information is shorter than the distance between the surface of the bottom electrode and the surface of the bottom electrode pad, the bottom electrode does not come into contact with the solder paste, and is not electrically connected to the bottom electrode pad by the solder paste.

In Figures 4 and 5, Sub is a substrate with multiple wiring layers formed therein, D2 is a second electronic component, e1 and e2 are terminal electrodes of the second electronic component D2, e3 is a bottom electrode of the second electronic component D2, EP1 and EP2 are electrode pads to which the terminal electrodes e1 and e2 of the second electronic component D2 are connected, EP3 is a bottom electrode pad to which the bottom electrode e3 of the second electronic component D2 is connected, H1 and H2 are solder paste applied to the electrode pads EP1 and EP2 after reflow, H3 is solder paste applied to the bottom electrode pad EP3 after reflow, S is a printed symbol print, and R is a solder resist.

The verification result output file 22 serves as a cache memory that temporarily stores, as output files, the judgment results and error information from the calculation unit 21 for each electronic component, along with solder paste thickness information and symbol print thickness information from the external input device 4 and the conditions transformed by the model transformation unit 14, and links them to the names and model names of the electronic components, and outputs the stored output files to the display device 5.
The display device 5 is a display used in a CAD system.

When the solder paste thickness information from the external input device 4 is changed and mounting verification is performed, the verification result output file 22 temporarily stores the change history, the judgment results from the calculation unit 21 for each change to the solder paste thickness, error information, the solder paste thickness information from the external input device 4, the symbol print thickness information, and the conditions changed by the model transformation unit 14, as well as the name and model name of the electronic component.

The electronic component mountability checking device 1 according to the first embodiment is used in a system using CAD, and is configured with a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input interface section, and an output interface section of a computer used as the CAD, as shown in Fig. 6, and loads a program stored in the ROM into the RAM, and the CPU executes various processes based on the program loaded into the RAM. The mountability checking device 1 is driven by a general-purpose OS (Operating System).
The CPU controls and manages the input interface unit, RAM, ROM, and output interface unit.
The CPU executes the process of verifying the mountability according to the program stored in the ROM.

The input unit 11 is controlled and managed by the CPU, and is composed of an input interface unit and a RAM.
The electronic component selection unit 12 is a function controlled and managed by the CPU.
The model generating unit 13, the model transforming unit 14, and the calculation unit 21 are each composed of a CPU, a ROM, and a RAM.
The verification result output file 22 is controlled and managed by the CPU, and is composed of an output interface section and a RAM.

The program stored in the ROM and executed by the CPU includes the steps of: generating first three-dimensional information indicating a three-dimensional solder paste model of the solder paste connecting the electrodes of the electronic component and the electrode pads on the substrate from the planar shape of the electrode pads and thickness information of the solder paste obtained from information indicating the opening shape of a two-dimensional metal mask used to print solder paste, which is placed on a substrate on which surface-mount electronic components are mounted; generating second three-dimensional information indicating a three-dimensional symbol print model from information indicating a two-dimensional symbol print, which is a display representing the electronic component to be printed on the surface of the substrate, and thickness information of the symbol print; generating deformed three-dimensional information indicating a deformed three-dimensional symbol print model in which the volume of the solder paste is kept constant and the three-dimensional shape of the solder paste is changed from the first three-dimensional information; determining whether the electronic component has a bottom electrode; and, if it is determined that the electronic component is a first electronic component that does not have a bottom electrode, forming an electrode of the first electronic component on the substrate with solder paste according to the deformed three-dimensional information. a step of judging whether the ratio of the area of the contact area of the solder paste based on the deformed three-dimensional information to the area of the planar shape of the electrode pad when connected to the electrode pad is within or outside a first specified range, and if it is outside the first specified range, deciding that the first electronic component is connected at an angle to the surface of the board by the solder paste based on the deformed three-dimensional information, and deciding that it is an error; and a step of deciding that the electronic component is a second electronic component having bottom electrodes, The method includes a procedure for comparing the thickness of the solder paste based on the deformed three-dimensional information with the distance between the surface of the bottom electrode of the second electronic component and the surface of the electrode pad that the bottom electrode faces when connecting the bottom electrode of the second electronic component to the bottom electrode pad that faces the bottom electrode by the test, and if the thickness of the solder paste based on the deformed three-dimensional information is shorter than the distance between the surface of the bottom electrode of the second electronic component and the surface of the bottom electrode pad that the bottom electrode faces, an error is generated because the bottom electrode of the second electronic component does not come into contact with the solder paste based on the deformed three-dimensional information.

Next, a method for checking mountability using the electronic component mountability checking device will be described with reference to the flow charts shown in FIGS.
As shown in FIG. 7, in step ST1, the input unit 11 acquires information in the board data 2, which is three-dimensional data indicating the wiring layer, electrode pads and bottom electrode pads, and solder resist that form the circuit pattern, and two-dimensional data indicating the planar shape of the symbol print and metal mask.

In step ST2, the input unit 11 acquires external shape information of the electronic component in the three-dimensional electronic component data 3, that is, three-dimensional dimensional information of the body and electrodes of the electronic component.
In step ST3, the input unit 11 acquires the solder paste thickness information and the symbol print thickness information from the external input device 4.

Step ST4 is a step in which the electronic component selection unit 12 selects an electronic component from a plurality of surface-mount electronic components to be mounted on a substrate, and for the selected electronic component, the model generation unit 13 generates first three-dimensional information indicating a three-dimensional solder paste model of a solder paste that connects an electrode of the electronic component to an electrode pad facing the electrode.
In the following steps, the surface mount electronic components selected by the electronic component selection unit 12 will be simply referred to as electronic components.

In step ST4, the first three-dimensional information is generated by the model generation unit 13 first calculating the planar shape of the electrode pad from information indicating the opening shape of a two-dimensional metal mask in the board data 2 input via the input unit 11, which is placed on the board and used to print solder paste.
Next, first three-dimensional information representing a three-dimensional solder paste model is generated from the calculated planar shape of the electrode pad and solder paste thickness information input from external input device 4 via input unit 11.

When the electronic component is a first electronic component (without bottom electrodes), the first three-dimensional information is information for a solder paste for connecting the terminal electrodes and the electrode pads.
When the electronic component is a second electronic component (with bottom electrodes), the first three-dimensional information is information for a solder paste for connecting the terminal electrodes and electrode pads, and a solder paste for connecting the bottom electrodes and bottom electrode pads.

Step ST5 is a step of generating second three-dimensional information showing a three-dimensional symbol print model of the symbol print, which is a representation of the electronic components printed on the surface of the solder resist on the surface of the substrate directly below the electronic components.

In step ST5, the model generation unit 13 generates second three-dimensional information representing a three-dimensional symbol print model from information representing the planar shape of the symbol print in the board data 2 input via the input unit 11 and thickness information of the symbol print from the external input device 4 input via the input unit 11.

In step ST6, the model transformation unit 14 generates, from the first three-dimensional information generated in step ST4, deformed three-dimensional information indicating a deformed three-dimensional solder paste model in which the volume of the solder paste is kept constant and the three-dimensional shape of the solder paste is changed.

In step ST7, if the electrodes in the information indicating the external shape of the electronic component in the three-dimensional electronic component data 3 input via the input unit 11 interfere with the symbol print in the second three-dimensional information generated in step ST5, that is, if they interfere with each other based on the positional relationship of whether they are in contact or not, the model transformation unit 14 corrects the position of the electronic component to a position where the electrodes do not interfere with the symbol print.

In step ST8, the calculation unit 21 determines whether the electronic component selected by the electronic component selection unit 12 has a bottom electrode. If it is a first electronic component that does not have a bottom electrode, the calculation unit 21 proceeds to step ST21 shown in FIG. 8, and if it is a second electronic component that has a bottom electrode, the calculation unit 21 proceeds to step ST31 shown in FIG. 9.

As shown in FIG. 8, step ST21 is a step in which the calculation unit 21 compares the area ratio of the contact area in the solder paste to the application area or the area ratio of the contact area in the solder paste to the area of the contact surface or surface area of the electrode with the first specified range, and obtains a comparison result.

That is, in step ST21, the calculation unit 21 compares the area ratio of the contact area of the solder paste when the electrode of the first electronic component is connected to the electrode pad facing the electrode of the first electronic component using the solder paste based on the deformed three-dimensional information generated in step ST4, that is, the area ratio of the contact area where the solder paste based on the deformed three-dimensional information contacts the electrode of the first electronic component to the area of the planar shape of the electrode pad or the area of the contact surface of the electrode or the surface area, with the first specified range.

The first specified range is a range that is set based on the ratio of the area of the contact surface of the electrode of the first electronic component that is in contact with the solder paste based on the deformation three-dimensional information to the surface area of the contact surface or the surface area of the electrode of the first electronic component. For example, the first specified range is set to a range from a set percentage to 100% or less.
Hereinafter, the area ratio of the contact area to the terminal electrode of the electronic component is referred to as the contact area ratio of the solder paste.

If the calculation unit 21 determines that the contact area ratio of the solder paste satisfies the first specified range, i.e., is within the first specified range, the process proceeds to step ST22, and if the calculation unit 21 determines that the contact area ratio is not satisfied, i.e., is outside the first specified range, the process proceeds to step ST23. In step ST23, it is determined that the first electronic component is connected at an angle to the surface of the board due to the solder paste based on the deformed three-dimensional information, so an error is generated, and the process proceeds to step ST41.

In step ST23, the calculation unit 21 temporarily stores information on the name of the electrode whose contact area ratio in question is outside the first specified range and error information indicating the reason, etc., in the memory unit of the verification result output file 22, linking it to the first electronic component.
FIG. 3 shows an example of a state in which the first electronic component is connected at an angle to the surface of the substrate.

In step ST22, the calculation unit 21 checks the contact state with the solder paste for all electrodes of the first electronic component using the three-dimensional deformation information, and if it determines that all electrodes are in good contact with the solder paste, it proceeds to step ST41. If it determines that the contact state of any one of the electrodes with the solder paste is not good, it proceeds to step ST23.

In step ST23, it is determined that an error has occurred since the electrodes of the first electronic component are not properly connected to the electrode pads, and the process proceeds to step ST41.
In step ST23, the calculation unit 21 temporarily stores information on the name of the electrode that has poor contact with the solder paste where the error occurred and error information indicating the reason, etc., in the memory unit of the verification result output file 22, linking it to the first electronic component.

In step ST41, the calculation unit 21 determines whether or not verification has been completed for all electronic components mounted on the board. If verification has not been completed, the calculation unit 21 returns to step ST4 and repeats the operations from step ST41 onwards for the electronic components that have not been verified. When verification of all electronic components has been completed, the calculation unit 21 proceeds to step ST42.

In step ST42, under the instruction from the calculation unit 21 that the verification of all electronic components has been completed, the verification result output file 22 outputs the temporarily stored output file, i.e., for all electronic components, for each change if there is a change history, the judgment results and error information from the calculation unit 21 for each electronic component, along with the solder paste thickness information and symbol print thickness information from the external input device 4 and the conditions changed by the model transformation unit 14, to the name and model name of the electronic component, and outputs the output file to the display device 5.

On the other hand, if the calculation unit 21 determines in step ST8 shown in FIG. 7 that the electronic component is a second electronic component having bottom electrodes, the process proceeds to step ST31 and subsequent steps shown in FIG.
The second electronic component includes steps ST31 and ST32 for determining the contact state between the terminal electrodes and the solder paste, and steps ST33 and ST34 for determining the contact state between the bottom electrodes and the solder paste.

Step ST31 is the same as step ST21 for the first electronic component.
That is, step ST31 is a step of comparing the area ratio of the contact area in the solder paste to the surface area of the terminal electrode (lead) of the second electronic component with the first specified range to obtain a comparison result.

If the calculation unit 21 determines that the contact area ratio of the solder paste is within the first specified range, the process proceeds to step ST32, and if it determines that it is outside the first specified range, the process proceeds to step ST23.
In step ST32, the calculation unit 21 checks the contact state with the solder paste for all the terminal electrodes of the second electronic component using the deformation three-dimensional information, and if it determines that all the terminal electrodes are in good contact with the solder paste, it proceeds to step ST41. If it determines that the contact state of any one of the terminal electrodes with the solder paste is not good, it proceeds to step ST23.

On the other hand, step ST33 for determining the contact state between the bottom electrodes and the solder paste is a step for verifying whether the solder paste reaches the bottom electrodes.
Simply put, calculation unit 21 compares the thickness of the solder paste with the distance from the surface of the bottom electrode of the second electronic component to the surface of the bottom electrode pad.

That is, in step ST33, the calculation unit 21 compares the distance from the surface of the bottom electrode of the second electronic component to the surface of the bottom electrode pad when connecting the bottom electrode of the second electronic component to the bottom electrode pad facing the bottom electrode of the second electronic component using solder paste based on the deformed three-dimensional information generated in step ST4 with the thickness of the solder paste based on the deformed three-dimensional information.

If the calculation unit 21 determines that the thickness of the solder paste based on the deformed three-dimensional information satisfies the second specified range with respect to the distance from the surface of the bottom electrode of the second electronic component to the surface of the bottom electrode pad, in other words, that it is outside the second specified range, in other words, that it is too long, it proceeds to step ST32 as the bottom electrode will be in contact with the solder paste, and if it determines that it does not satisfy the second specified range, in other words, that it is within the second specified range, in other words, that it is too short, it proceeds to step ST23 as the bottom electrode will not be in contact with the solder paste, and in step ST23, it determines that the bottom electrode of the second electronic component will not be in contact with the solder paste based on the deformed three-dimensional information, so it is an error, and it proceeds to step ST41.

Surface mount electronic components as the second electronic component generally have lead terminals as terminal electrodes, and as shown in FIG. 4, the lead terminals sink into the solder paste, so it is advisable to take into consideration the amount by which the lead terminals sink into the solder paste.
That is, the distance from the tip of the lead terminal to the surface of the electrode pad may be subtracted as a correction value from the thickness of the solder paste based on the three-dimensional deformation information and the distance from the surface of the bottom electrode to the surface of the bottom electrode pad.

In this case, it is sufficient to satisfy (thickness of solder paste based on deformed three-dimensional information) - (distance from the tip of the lead terminal to the surface of the electrode pad) > (distance from the surface of the bottom electrode to the surface of the bottom electrode pad) - (distance from the tip of the lead terminal to the surface of the electrode pad).
In other words, if the thickness of the solder paste based on the deformed three-dimensional information is longer than the distance from the surface of the bottom electrode of the second electronic component to the surface of the bottom electrode pad, it satisfies the second specified range, and if it is shorter, it does not satisfy the second specified range.

By satisfying the above formula, it is possible to determine whether the solder paste reaches the bottom electrode even if the mounting position of the main body of the second electronic component is slightly raised above the surface of the board, using the symbol print printed directly below the second electronic component.

Step ST34 is a step for verifying whether or not the contact area between the bottom electrodes of the second electronic component and the solder paste after reflow exceeds a set value.
In step ST34, the calculation unit 21 calculates the volume of the solder paste after reflow, which is the value obtained by multiplying the thickness of the solder paste based on the deformed three-dimensional information by the planar shape of the solder paste based on the three-dimensional information, and the minimum spatial volume, which is the value obtained by multiplying the distance between the surface of the bottom electrode of the second electronic component and the surface of the bottom electrode pad that the bottom electrode faces by the planar area of the bottom electrode.

Next, the calculation unit 21 compares the volume ratio of the volume of the solder paste after reflow to the minimum space volume with a third specified range.
If the calculation unit 21 determines that the volume ratio satisfies the third specified range, in other words, is outside the third specified range, in other words, that the volume of the solder paste after reflow is greater than the minimum space volume, it determines that the solder paste after reflow is sufficient and proceeds to step ST41.

If the volume ratio does not satisfy the third specified range, that is, if it is within the third specified range, that is, if the volume of the solder paste after reflow is smaller than the minimum space volume, the process proceeds to step ST23. In step ST23, it is determined that there is an error in that there is a shortage of solder paste after reflow, and the process proceeds to step ST41.
In step ST23 and step ST41, the operation is performed in the same manner as when the electronic component is the first electronic component.

The third specified range is a range that is set based on the ratio of the volume of the solder paste after reflow to the minimum spatial volume, and is a ratio that indirectly indicates the ratio of the area of the bottom electrode that the solder paste after reflow contacts. For example, the third specified range is set to a set percentage or less, and if the volume ratio is outside the third specified range, it is determined that the third specified range is satisfied, and if it is within the third specified range, it is determined that the third specified range is not satisfied.

As described above, the electronic component mountability confirmation device according to the first embodiment includes a model generation unit that generates three-dimensional information representing a three-dimensional solder paste model of the solder paste from the planar shape of the electrode pad obtained from the opening shape of the two-dimensional metal mask and the thickness information of the solder paste, a model transformation unit that changes the three-dimensional information representing the three-dimensional solder paste model into deformed three-dimensional information representing a deformed solder paste model in which the volume of the solder paste is constant and the three-dimensional shape of the solder paste is changed, and a calculation unit that determines whether the relationship between the electrodes of the electronic component and the solder paste based on the deformed three-dimensional information generated by the model transformation unit satisfies a specified range and issues an error if the specified range is not satisfied. Therefore, it is possible to determine whether the relationship between the electrodes of the electronic component and the solder paste based on the deformed three-dimensional information generated by the model transformation unit satisfies a specified range, and to determine whether the connection between the electrodes of the electronic component and the electrode pads by the solder paste is good or not before actually mounting the surface-mount electronic component on the board, and to predict and determine whether the electronic component can be correctly mounted on the board.

For electronic components that have a symbol print on the surface of the board directly underneath, the calculation unit compares the area ratio of the contact area where the solder paste comes into contact with the electrodes of the electronic component, based on the three-dimensional deformation information relative to the area of the planar shape of the electrode pad, with the specified range, and determines whether the area ratio is inside or outside the specified range. If it is outside the specified range, an error is generated, so that the connection status between the terminal electrodes of the electronic component and the electrode pads can be easily known.

For electronic components with bottom electrodes, the calculation unit compares the thickness of the solder paste based on the three-dimensional deformation information with the distance from the surface of the bottom electrode of the electronic component to the surface of the bottom electrode pad that the bottom electrode faces, and if the thickness is shorter than the distance, an error is generated, making it easy to know the connection state between the bottom electrode of the electronic component and the bottom electrode pad.

The components in the embodiments can be freely combined, and any components can be modified or omitted.

The electronic component mountability confirmation device according to the present disclosure is used in a CAD system that designs the mounting of surface-mount electronic components on a printed circuit board, and is suitable as an electronic component mountability confirmation device for predicting and determining whether an electronic component can be correctly mounted on a board before the electronic component is actually mounted on the board.

1 Electronic component mountability confirmation device, 10 Shape calculation device, 11 Input unit, 12 Electronic component selection unit, 13 Model generation unit, 14 Model transformation unit, 20 Design verification device, 21 Calculation unit, 22 Verification result output file.

Claims (6)

a model generating unit that generates three-dimensional information representing a three-dimensional solder paste model of the solder paste that connects the electrodes of the electronic components and the electrode pads on the substrate from information on the planar shape of the electrode pads and thickness of the solder paste obtained from the opening shape of a two-dimensional metal mask that is placed on a substrate on which a surface mount electronic component is mounted and is used to print the solder paste;
a model transformation unit that changes three-dimensional information representing the three-dimensional solder paste model generated by the model generation unit into transformed three-dimensional information representing a transformed solder paste model in which a volume of the solder paste is kept constant and a three-dimensional shape of the solder paste is changed;
a calculation unit that determines whether or not a relationship between the electrodes of the electronic component and the solder paste based on the three-dimensional deformation information generated by the model deformation unit satisfies a designated range, and issues an error when the designated range is not satisfied;
An electronic component mountability confirmation device comprising: The substrate has a symbol print, which is an indication of the electronic component, printed on a surface of the substrate directly below the electronic component;
a relationship between the electrodes of the electronic component and the solder paste based on the three-dimensional deformation information generated by the model deformation unit is an area ratio of a contact area where the solder paste based on the three-dimensional deformation information contacts the electrodes of the electronic component to an area of a planar shape of the electrode pad;
The electronic component mountability checking device according to claim 1 . the electronic component has a bottom electrode on a bottom surface of a body;
The relationship between the electrodes of the electronic component and the solder paste based on the three-dimensional deformation information generated by the model deformation unit is a thickness of the solder paste based on the three-dimensional deformation information relative to a distance from a surface of the bottom electrode of the electronic component to a surface of a bottom electrode pad facing the bottom electrode.
The electronic component mountability checking device according to claim 1 . a model generating unit generating first three-dimensional information representing a three-dimensional solder paste model of the solder paste connecting the electrodes of the electronic components and the electrode pads on the substrate from planar shapes of electrode pads and thickness information of the solder paste obtained from information representing opening shapes of a two-dimensional metal mask used for printing solder paste, the metal mask being disposed on a substrate on which a surface mount electronic component is mounted;
a step of generating second three-dimensional information representing a three-dimensional symbol print model from information representing a two-dimensional symbol print, which is a representation representing the electronic component printed on the surface of the substrate, and thickness information of the symbol print by the model generating unit;
a model transformation unit generating, from the first three-dimensional information, transformed three-dimensional information indicating a transformed three-dimensional solder paste model in which a volume of the solder paste is kept constant and a three-dimensional shape of the solder paste is changed;
A calculation unit determines whether the electronic component has a bottom electrode;
a step of determining, when the calculation unit determines that the electronic component is a first electronic component having no bottom surface electrode, whether an area ratio of a contact area where the solder paste based on the deformed three-dimensional information contacts the electrode of the first electronic component to an area of a planar shape of the electrode pad when the electrode of the first electronic component is connected to the electrode pad facing the electrode of the first electronic component by the solder paste based on the deformed three-dimensional information is within or outside a first specified range, and if it is outside the first specified range, determining that the first electronic component is connected at an angle with respect to the surface of the board by the solder paste based on the deformed three-dimensional information, and determining an error;
when the calculation unit determines that the electronic component is a second electronic component having a bottom electrode, the calculation unit compares a distance from a surface of the bottom electrode of the second electronic component to a surface of the bottom electrode pad facing the bottom electrode of the second electronic component with a thickness of the solder paste based on the deformation three-dimensional information when connecting the bottom electrode of the second electronic component to a bottom electrode pad facing the bottom electrode of the second electronic component with a solder paste based on the deformation three-dimensional information, and if the thickness of the solder paste based on the deformation three-dimensional information is shorter than the distance from the surface of the bottom electrode of the second electronic component to the surface of the bottom electrode pad facing the bottom electrode, the calculation unit determines that the bottom electrode of the second electronic component is not in contact with the solder paste based on the deformation three-dimensional information and determines an error;
The method for verifying mountability of an electronic component is provided. a step of generating first three-dimensional information representing a three-dimensional solder paste model of the solder paste connecting the electrodes of the electronic component and the electrode pads on the substrate from planar shapes of electrode pads and thickness information of the solder paste obtained from information representing opening shapes of a two-dimensional metal mask used for printing solder paste, the metal mask being disposed on a substrate on which a surface mount electronic component is mounted;
generating second three-dimensional information representing a three-dimensional symbol print model from information representing a two-dimensional symbol print, which is a representation representing the electronic component printed on the surface of the substrate, and thickness information of the symbol print;
generating, from the first three-dimensional information, modified three-dimensional information indicating a modified three-dimensional symbol print model in which the volume of the solder paste is kept constant and the three-dimensional shape of the solder paste is changed;
determining whether the electronic component has a bottom electrode;
a step of determining whether an area ratio of a contact area of the solder paste based on the deformed three-dimensional information contacting an electrode of the first electronic component to an area of a planar shape of the electrode pad when the electrode of the first electronic component is connected to an electrode pad on the board by the solder paste based on the deformed three-dimensional information is within or outside a first specified range, and determining that the area ratio is outside the first specified range because the first electronic component is connected at an angle with respect to the surface of the board by the solder paste based on the deformed three-dimensional information, resulting in an error;
a step of comparing a distance from a surface of the bottom electrode of the second electronic component to a surface of the bottom electrode pad facing the bottom electrode of the second electronic component with a thickness of the solder paste based on the deformed three-dimensional information when connecting the bottom electrode of the second electronic component to a bottom electrode pad facing the bottom electrode of the second electronic component with a solder paste based on the deformed three-dimensional information, and determining that the bottom electrode of the second electronic component is not in contact with the solder paste based on the deformed three-dimensional information and an error when the thickness of the solder paste based on the deformed three-dimensional information is shorter than the distance from the surface of the bottom electrode of the second electronic component to the surface of the bottom electrode pad facing the bottom electrode of the second electronic component;
The electronic component mounting confirmation program executes the above on a computer. a step of generating first three-dimensional information representing a three-dimensional solder paste model of the solder paste connecting the electrodes of the electronic component and the electrode pads on the substrate from planar shapes of electrode pads and thickness information of the solder paste obtained from information representing opening shapes of a two-dimensional metal mask used for printing solder paste, the metal mask being disposed on a substrate on which a surface mount electronic component is mounted;
generating second three-dimensional information representing a three-dimensional symbol print model from information representing a two-dimensional symbol print, which is a representation representing the electronic component printed on the surface of the substrate, and thickness information of the symbol print;
generating, from the first three-dimensional information, modified three-dimensional information indicating a modified three-dimensional symbol print model in which the volume of the solder paste is kept constant and the three-dimensional shape of the solder paste is changed;
determining whether the electronic component has a bottom electrode;
a step of determining whether an area ratio of a contact area of the solder paste based on the deformed three-dimensional information contacting an electrode of the first electronic component to an area of a planar shape of the electrode pad when the electrode of the first electronic component is connected to an electrode pad on the board by the solder paste based on the deformed three-dimensional information is within or outside a first specified range, and determining that the area ratio is outside the first specified range because the first electronic component is connected at an angle with respect to the surface of the board by the solder paste based on the deformed three-dimensional information, resulting in an error;
a step of comparing a distance from a surface of the bottom electrode of the second electronic component to a surface of the bottom electrode pad facing the bottom electrode of the second electronic component with a thickness of the solder paste based on the deformed three-dimensional information when connecting the bottom electrode of the second electronic component to a bottom electrode pad facing the bottom electrode of the second electronic component with a solder paste based on the deformed three-dimensional information, and determining that the bottom electrode of the second electronic component is not in contact with the solder paste based on the deformed three-dimensional information and an error when the thickness of the solder paste based on the deformed three-dimensional information is shorter than the distance from the surface of the bottom electrode of the second electronic component to the surface of the bottom electrode pad facing the bottom electrode of the second electronic component;
A recording medium storing a program for causing a computer to execute the above.

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