JPH0213802A - Mounting state inspecting device for circuit part - Google Patents

Abstract

PURPOSE:To judge the quality of soldering three-dimensionally by determining a volume of a soldered part from a solder area data and a solder height data to determine whether a solder volume value is within a range of a prescribed value. CONSTITUTION:A printed board with a circuit part mounted is irradiated with light, reflected light thereof is detected by a brightness detection means 1 and a solder area is judged by a solder area judging means 2 from brightness information obtained. On the other hand, a surface height on a printed wiring board is detected by a height detection means 3. From the above solder area information and height information, the height of a solder area is extracted by a height data extraction means 4. From the height data extracted and a part size stored in a part size data memory means 5, a solder volume is computed by a solder volume computing means 6. The solder volume computed and a prescribed volume of a prescribed volume memory means 7 are compared by a means 8 for judging the quality of the adhesion of solder to judge the quality of the solder adhesion.

Description

Detailed Description of the Invention: Table of Contents Overview Industrial Fields of Use Conventional Technology Means for Solving Problems to be Solved by the Invention (Fig. 1) Working Examples First Embodiments (Second to Figure 7) Second embodiment (Figures 8A and 8B) Expanded effect of the invention [Summary] and circuit component mounting condition inspection device for inspecting the actual device condition of circuit components mounted on a printed wiring board. A luminance method that detects the brightness of the surface of a printed wiring board with circuit components mounted by receiving the reflected light irradiated on the surface of the printed wiring board, with the aim of more accurately determining the quality of the circuit component mounting condition from the viewpoint of quantity. a detection means; a solder area determination means for determining a flat area of a solder portion welded to a circuit component and a printed wiring board from the detected brightness as seen from above the printed wiring board; surface height detection means for detecting the surface height; height data extraction means for extracting only the height data belonging to the solder portion plane area from the detected surface height data; a written component size data storage means; a solder volume calculation means for calculating the volume of a predetermined area of the solder portion using the extracted height data and the written component size data; Solder adhesion quality determination for determining the quality of solder adhesion by comparing the specified volume storage means in which the specified volume range is written, and the determined volume of a predetermined area of the solder portion and the corresponding specified range. and a determination result output means for outputting the quality determination result.

[Industrial Field of Application] The present invention relates to a circuit component mounting state inspection device that inspects the mounting state of circuit components mounted on a printed wiring board from the viewpoint of solder adhesion amount.

[Prior Art] Conventionally, this type of circuit component mounting state inspection device reads luminance data using an image sensor, binarizes it, determines a bright area as a solder attachment area, and compares it with a reference pattern. The quality of the circuit component mounting condition was determined by

[Problem to be solved by the invention] However, since the inspection is performed on a flat surface, the amount of solder adhesion may be insufficient or excessive, or the distribution of the amount of solder adhesion may be uneven and biased. However, if the planar distribution is normal, it is determined to be good, and the circuit component mounting state may be incorrectly determined to be good or bad.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide a circuit component mounting state inspection device that can more accurately determine the quality of a circuit component mounting state from the viewpoint of solder adhesion amount.

[Means to solve the problem] FIG. 1 is a diagram showing the principle of the present invention.

In the figure, l denotes a brightness detection means, which detects the brightness of the surface of the printed wiring board on which the circuit components are mounted by receiving the reflected light of the light irradiated onto the surface of the printed wiring board.

2 is a solder area determination means, and from the detected brightness,
A plane area of a solder portion welded to a circuit component and a printed wiring board as viewed from above the printed wiring board is determined.

3 is a surface height detection means, which detects the surface height on the printed wiring board.

Reference numeral 4 denotes a height data extracting means, which extracts only height data belonging to the solder portion plane area from the detected surface height data.

Reference numeral 5 denotes a component size data storage means in which size data of circuit components is written.

Reference numeral 6 denotes a solder volume calculation means, which calculates the volume of a predetermined area of the solder portion using the extracted height data and written component size data.

Reference numeral 7 denotes a specified volume storage means, in which a specified range of the volume of the predetermined area of the solder portion is written.

Reference numeral 8 denotes a solder adhesion quality determining means, which compares the determined volume of a predetermined area of the solder portion with the corresponding specified range to determine the quality of the solder adhesion state.

Reference numeral 9 denotes a determination result output means, which outputs the determination result.

The above luminance detection means! The surface height detection means 3 is configured using, for example, a optical position detector (PSD).

Further, the upper solder area determination means 2, for example, binarizes the detected surface luminance and divides it into a bright part and a dark part, and determines an area in which bright parts that are close to each other are connected to be a solder part plane area.

Further, the predetermined area of the solder portion may be one continuous area, for example.
These are two solder areas, or each area obtained by dividing one continuous solder area.

[Operation] The solder area is determined in a two-dimensional manner based on the brightness data. According to this brightness data, the solder portion and the wiring board portion can be clearly distinguished regardless of the height of the solder.

Therefore, even if the solder area is extremely low, the area can be determined accurately.

Of the height data, only the height data of this solder area is extracted, and the volume of a predetermined area of only solder is calculated using pre-stored component size data, and compared with the pre-stored specified volume. , the quality of solder adhesion is determined.

Therefore, it is possible to determine the quality of the solder adhesion state three-dimensionally, and to detect solder adhesion defects that cannot be detected by a two-dimensional inspection of the solder adhesion state using only luminance signals.

[Example] Hereinafter, the present invention will be explained in detail based on the drawings.

(+) First Embodiment FIG. 2 shows the basic configuration of an optical system of a circuit component mounting state inspection apparatus.

Printed wiring board 12 placed on x-y stage lO
On the top, a chip component 14 as a circuit component is soldered 16A.
, 16B.

On the other hand, above the x-y stage IO is a polygon mirror 1.
A semiconductor laser 20 is disposed on the side of the polygon mirror 18 with its tip axis facing the polygon mirror 18, and a collimating lens 22 is disposed between the polygon mirror 18 and the semiconductor laser 20 with its tip pointing toward the polygon mirror 18. The axis is the semiconductor laser 20
The optical axis of the lens is aligned with the optical axis of the Further, on the side of the polygon mirror 18 in the direction substantially perpendicular to the front axis, there is a mark "
A mirror 25 is disposed through the θ lens 24, and the mirror 2
An optical sensor 26 is disposed on the side of the polygon mirror 5 with its front axis facing the polygon mirror 18. A stepping motor 18λ is connected to the rotation axis of the polygon mirror 18, and a pulse generator 18b is connected to the rotation axis of the stepping motor 18a.

Therefore, the laser beam emitted from the semiconductor laser 20 is collimated by the collimating lens 22, reflected by one surface of the polygon mirror I8, passes through the fθ lens 24,
Next, the light is reflected downward by the mirror 25 and illuminates the surface of the printed wiring board 12 to form a light spot. Polygon mirror by stepping motor 18a! 8, the laser beam LB is periodically swung in the X direction in FIG. The optical sensor 26 outputs a periodic synchronizing pulse S corresponding to the periodic synchronization pulse S. (See FIG. 5) Also, one rotation pulse S+ is output from the pulse generator 18b each time the polygon mirror 18 rotates by a certain minute angle (see FIG. 5).

The x-y plane position coordinates of the light spot on the printed wiring board 12 are obtained as follows.

In other words, the polygon mirror 18 is stationary and the x-y stage! When O is moving, the device coordinates (X, Y) formed by the x-y stage 18 can be used as the position coordinates of the light spot. Here, it is assumed that the X-axis direction is parallel to the scanning direction of the light spot, and the Y-axis direction is perpendicular to the scanning direction of the light spot.

In reality, the polygon mirror 18 rotates, for example, in the direction of arrow A in FIG. 2, and the light spot illuminates the printed wiring board! 2 x-y stage every time you scan the top! 0 is in the Y-axis direction! step,
For example, move by 10 μ■. Therefore, the coordinate value X of the x-Y stage position coordinates (X, Y) is calculated by calculating the scanning pulse S, which ignores a predetermined number of pulses before and after the synchronizing pulse S among the rotating pulses SI, as shown in FIG. By replacing it with the numerical value Cx, the position coordinates of the light spot are obtained. This count value Cx is cleared by the synchronization pulse S.

If the data sampling range in one scan of the light spot is smaller than the width of the printed wiring board 12 in the X direction,
- It is necessary to move the Y stage IO a certain distance block in the X direction, and the X coordinate of the light spot is obtained by combining the coordinate value X of the xY stage IO and the above count value Cx.

Next, the Z direction of the light spot (direction perpendicular to the X-Y plane)
The position and brightness of the light spot surface will be explained.

A optical position detector (PSD) 30 is disposed diagonally above the XY stage 10 via an imaging lens 28. As shown in FIG. 4A, the output terminal 30a of the optical position detector 30
, 30b is 11, if, the light spot position of the laser beam LB irradiated onto the surface of the printed wiring board 12 is (t + -if)/(t ,
+ t t), and the brightness of the light spot surface is (+++
i*).

The light spots A%B and C on the substrate I4 are focused and imaged at positions A°, Bo and C′ on the light receiving surface of the optical position detector 30, respectively. Therefore, the Z-direction position of the light spot can be determined from the correspondence between the two.

FIG. 4B shows the relationship between these positions and (i + −i *)/(it+ i *).

In this embodiment, for the sake of simplicity, a case will be explained in which one optical position detector 30 is provided, but in FIG. The configuration may be such that the information is acquired by switching between the two.

Next, the overall hardware configuration of the circuit component mounting state inspection apparatus will be explained based on FIG.

The current +1sll taken out from the two output terminals of the optical position detector 30 is amplified by amplifiers 32 and 34, respectively, and becomes 1. ．． 11, and these are supplied to the adder 36 and the subtracter 38, and they become ■1+■2, I+Ig, respectively.
is created. I++In corresponds to the brightness of the light spot surface, and is digitally converted by the A/D converter 40.
It is written to a predetermined address in the brightness memory 42 under DMA control. This address is the X-
Address creation circuit 4, which is equal to the Y plane position coordinate and will be described later.
3.

On the other hand, the outputs of the adder 36 and the subtracter 38 are supplied to the divider 44, and the result is (I I-11) / (I , + I t)
is created. This value corresponds to the light position imaged on the light-receiving surface of the optical position detector 30, is digitally converted by the A/D converter 45, and written to the specified address in the height memory 46.

A brightness memory 42 and a height memory 46 are connected to path 48. Further connected to this bus 48 are an MPU 50, a program memory 52, a component data memory 54, a specified value memory 55, a work memory 56, a defective position output memory 58, and an output port 0. These various memories actually correspond to predetermined areas of the memory, but for convenience of explanation, they are shown as separate ones in FIG. In the component data memory 54, the coordinates of the center point of each component mounted on the printed wiring board 12, the arrangement direction of the component, the type of component, and the size data of various components are written.

These data are equal to the data used in the automatic component mounting apparatus, and do not need to be specially created for the circuit component mounting state inspection apparatus.

According to the program stored in the program memory 52,
When a rotation control pulse is supplied from the MPU 50 to the driver 62 via the output port 0, a drive pulse is supplied from the driver 62 to the stepping motor 18a for rotationally driving the polygon mirror 18, and the polygon mirror 18 is rotated. A rotation pulse S1 as shown in FIG. 5 is supplied to the address generation circuit 43. Further, a synchronization pulse St as shown in FIG. 5 is supplied from the optical sensor 26 to the address generation circuit 43.

The address creation circuit 43 creates the sampling pulse S as described above using these pulses 5lxS, and uses this sampling pulse S and the device coordinates composed of the X-Y stage IO to generate the light as described above. Create the X-Y plane position coordinates of the spot and output them as an address.

The address generation circuit 43 also includes an A/D converter 40.4.
4 to control the timing of data sampling and digital conversion.

X-Y7. The data IO is driven in steps in the Y-axis direction in synchronization with the synchronization pulse S supplied from the optical sensor 26 based on the movement control pulse supplied from the MPU 50 to the driver 64 via the output port 0, and is
Block driven in the axial direction.

Furthermore, if a solder adhesion defect is written in the defective position output memory 58, the defective position and type of defect are output to the defective position output device 66 via the output port 0. This defective position output device 66 is, for example, an X-Y plotter, and writes the defective position on a transparent sheet.

Next, a procedure for processing data written to the luminance memory 42 and the height memory 46 by DMA control will be explained based on FIG. 6.

(10G) In the brightness memory 42, a window 68 is set corresponding to each circuit component as shown in FIG. 7(A). Then, the luminance data within the window 68 is binarized. For example, a histogram of brightness data is created, and the threshold for binarization is set to the brightness at the midpoint between the peak with the highest brightness and the peak with the lowest brightness among a plurality of peaks. Through this binarization process, bright areas 70A, 70B and bright areas 72A, 72B that are close to each other are obtained as shown in FIG. 7(A). The dark areas between the bright areas 70A and 70g and between the bright areas 72A and 72B correspond to the steep slopes of the solders 16A and 16B shown in FIG. "l" is written in the bright part, and "0°" is written in the dark part.

(102) Next, bright areas 7 that are close to each other within a certain distance
Invert the data between 0A and 70B and connect them,
Inverting the data between the bright parts 72A and 72B and connecting them,
As shown in FIG. 7(B), these areas are soldered at 70G.
, 72G.

(104) Here, when the printed wiring board 12 has a large area, for example, 50 (lsm x 600 mm), there is a gentle warpage of about ±2 mm at the maximum, and on the other hand,
The minimum height of the chip component 14 is about 0.5 am.

Therefore, it is necessary to determine the height of the printed wiring board 12 for each window setting. Therefore, a window 74 corresponding to the window 68 is set in the height memory 46,
As shown in FIG. 7(C), inside the window 74 and the solder part 7
The height of the printed wiring board section 76 other than the area where 0C and the solder section 72C are connected.

Find the board height from the data.

(106) Next, logical product is performed for each corresponding address of the luminance binary data shown in FIG. 7(B) and the height data shown in FIG. 7(C). As a result, as shown in FIG. 7(D), the data in the window 74 other than the valid parts 70 and 72 becomes "0". That is, height data of only the solder portion is extracted.

(10g) Here, in Fig. 7 (E), -
Height data on a dash-dotted line 78 is shown. Effective part 70
．． The height data 72 includes the substrate height determined in step 1.4 and the height of the chip component 14 itself. Therefore, by subtracting these heights from the height of the solder portion, the height of only the solder portion is calculated as shown in FIG. 7(F). The height of the chip component 14 can be obtained by referring to the table in the component data memory 54 using the position of the window 74 as an index.

(110) Next, by determining the vertical cross-sectional area of each solder portion on both sides shown in FIG. The volume V of each of the solders 16A and 16B is calculated. This solder volume V is obtained by simply adding the data in the effective parts 70 and 72, respectively.

(112) If V < V ml 11, it is determined that there is a solder shortage, and (114) the data indicating the solder shortage and the position data of this chip component I4 are written as a pair to the defective position output memory 58.

(116) If V > V wax, it is determined that there is too much solder, and (11g) data indicating too much solder and the position data of this chip component 14 are paired and stored in the defective position output memory 58.
Write to.

(120) If the processing has not been completed for all circuit components, the process returns to step 100 and repeats the above processing.

When the processing has been completed for all parts, (122) the data stored in the defective position output memory 58 is outputted to the output device 66 via the output port 0.

Note that a conventional two-dimensional pattern check is also performed using the data stored in the brightness memory 42, and the defects are also written in the defect location output memory 58 and output to the output device 66.

(2) Second Embodiment Next, a second embodiment of the present invention will be explained based on FIGS. 8A and 8B.

FIG. 8A is a plan view of the chip component I4 mounted on the printed wiring board 12, and FIG. 8B is a sectional view taken along the line BB in FIG. 8A.

In the first embodiment, it was determined whether the solder volume of each of the solders 16A and 16B was within the specified range.
As shown in FIGS. 8A and 8B, if the distribution of solder adhesion amount is uneven, some soldering should be determined to be defective even if the total solder volume is within the specified range.

Therefore, in this second embodiment, the solder volume is determined for each of the solder portions 16a116b on both sides of the dividing plane 80 passing through the end surface of the chip component 14, and is compared with a specified value. The same applies to solder 16B shown in FIG.

Since the data processing procedure is clear from the description of the first embodiment, it will be omitted here.

(3) Expansion Note that the present invention includes various other modifications.

For example, in the above embodiment, a case has been described in which the brightness detection means and the surface height detection means are configured using an optical position detector, but an image sensor may be used instead of the optical position detector.

Furthermore, if the luminance is binarized using a comparator before writing the luminance data into the memory, the capacity of the luminance memory can be reduced.

In addition, multiple optical position detectors are installed to sufficiently receive reflected light from the steep solder slope.The brightness output of each optical position detector is binarized using a comparator, and one of the optical position detectors is compared. If the solder volume is determined in real time by cumulatively adding the height data only when it is determined that the device is in a bright area, the brightness memory and height memory will be unnecessary.

In addition, if the type of circuit component is determined by reading the pattern written on the circuit component from a set of luminance data, it is sufficient to write only the component type and size in the component size data storage means, making it highly versatile. .

[Effects of the Invention] As described above, according to the present invention, a solder area is determined in a two-dimensional manner based on brightness data, and only the height data of this solder area is extracted from the detected height data. The volume of a predetermined area of only solder is calculated using pre-stored component size data and compared with a pre-stored specified volume to determine the quality of solder adhesion, so it is possible to determine the quality of solder adhesion three-dimensionally. is determined, and even if the surface is normal but the amount of solder adhesion is insufficient or excessive,
It is possible to judge whether the solder adhesion is good or bad, and therefore it is possible to more accurately judge whether the circuit component mounting condition is good or bad, which is an excellent effect and greatly contributes to improving the reliability of electronic circuits. .

Furthermore, since the solder area is determined two-dimensionally using brightness data, it is possible to clearly distinguish between the solder area and the wiring board area regardless of the height of the solder, and it is possible to accurately distinguish even extremely low solder areas. It also has the excellent effect of being able to determine the area, thus accurately measuring the solder volume, and accurately determining whether the solder adhesion is good or bad.

When an optical position detector is used as the brightness detection means and the surface height detection means, the amount of data to be processed is small, the processing speed can be increased, and the configuration of the device can be simplified. play.

Further, by dividing one continuous solder region and performing the above-mentioned pass/fail judgment for each part, it is also possible to judge defects due to non-uniform distribution of solder adhesion amount.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the principle configuration of the present invention, FIG. 2 is an optical system layout diagram of a circuit component mounting state inspection apparatus according to the first embodiment of the present invention, and FIG. 3 is a circuit component mounting diagram according to the first embodiment. A block diagram showing the overall configuration of the condition inspection device, Figures 4A and 4B are diagrams explaining height detection, Figure 5 is a diagram explaining the planar position coordinates of the light spot, and Figure 6 is the processing of brightness data and height data. Flowchart showing the procedure, Figures 7 (A) to (F) are explanatory diagrams of the data processing procedure, Figure 8A
The figure is a partial plan view of the chip component 14 for explaining the second embodiment, and FIG. 8B is a sectional view taken along the line B--B in FIG. 8A. In the figure, IO is an X-Y stage] 2 is a printed wiring board 14 is a chip component +6A, 16B is a solder 18 is a polygon mirror 20 is a semiconductor laser 22 is a collimating lens 24 is an rθ lens 26 is an optical sensor 28 is an imaging lens 30 The optical position detector 80 is the optical system of the split-plane circuit component mounting condition inspection device.Figure 2.Height detection explanatory diagram.Figure 4A.Figure 4B.Processing procedure for brightness data and height data.Figure 6 (E) (F) Figure 7

Claims (1)

[Claims] (1) brightness detection means (1) for detecting the brightness of the surface by receiving reflected light of light irradiated on the surface of the printed wiring board with circuit components mounted; solder area determination means (2) for determining a flat area of a solder portion welded to a printed wiring board as seen from above the printed wiring board; and a surface height detection unit for detecting a surface height on the printed wiring board. Means (3); Height data extraction means (4) for extracting only height data belonging to the solder flat area from the detected surface height data; Size data of the circuit component is written. component size data storage means (5); solder volume calculation means (6) for calculating the volume of a predetermined area of the solder portion using the extracted height data and written component size data; Comparing the determined volume of the predetermined area of the solder part with the corresponding predetermined range with the predetermined volume storage means (7) in which the predetermined range of the volume of the predetermined area is written, and determines the solder adhesion state. A circuit component mounting state inspection apparatus comprising: a solder adhesion quality determining means (8) for determining the quality of the solder adhesion; and a determination result output means (9) for outputting the quality determination result. 2) The circuit component mounting state inspection apparatus according to claim 1, wherein the luminance detection means (1) and the surface height detection means (2) are constructed using an optical position detector (30). 3) The solder area determining means (2) binarizes the detected luminance and divides it into a bright part and a dark part (100), and determines an area where bright parts that are close to each other are connected to be a solder part flat area. 3. The circuit component mounting state inspection apparatus according to claim 1, further comprising: (102). 4) The predetermined region of the solder portion is one continuous solder region (16A, 16B).
The described circuit component mounting state inspection device. 5) The circuit component mounting state inspection device according to claim 1, wherein the predetermined regions of the solder portion are regions (16a, 16b) obtained by dividing one continuous solder region.