TW201350835A - Method of inspecting a wetting-up state of solder, automatic appearance inspecting device and substrate inspecting system using such a method - Google Patents

Abstract

The present invention is to provide a technique capable of determining a wetting-up state of solder in a soldered portion comprising a location where measurement of the appearance is difficult. After a solder printing process, inspection of a post-reflow inspection device 30 is performed onto a substrate, onto which a part mounting process and a reflow process are performed, after amount of cream solder applied to each land is measured. In this inspection device 30, photographing of a camera 302 which is in a state directly viewing a substrate surface of the inspection device is performed under illumination of an illumination device 305; with respect to the soldered portion which has a feature not appeared in a generated image and in which cream solder measured in regard to the corresponding land fulfills a predetermined excellent condition, a feature which is the featured not appeared in the image and related to a shape of a location of the soldered portion not appeared in the image is measured; and the fact whether wetting up of solder in the soldered portion is good or not is determined based on the result of this measurement.

Description

Method for inspecting adhesion state of solder, automatic visual inspection device using the same, and substrate inspection system

The present invention relates to an inspection method for inspecting a solder adhesion state of a component mounting position formed on a component mounting substrate, an automatic visual inspection device using the same, and a substrate inspection system.

Most of the inspection of the component mounting substrate is carried out by means of visual inspection by taking a picture with a camera. In the conventional automatic visual inspection device, a camera and an illumination device are disposed. The camera is placed above the platform portion of the support substrate in a state in which the optical axis is aligned in the vertical direction from the front, and the illumination device removes light from the illumination device. Each orientation is incident on the field of view of the camera, and the image is generated using specular reflected light from the soldered portion to the illumination light.

In such an automatic visual inspection device, there is a type of inspection device that illuminates a plurality of color lights in different directions from the elevation angle of the substrate, and according to the color distribution pattern appearing at the welded portion in the image. It is discriminated whether the tilt state of the solid fillet is appropriate or not (for example, refer to Patent Document 1).

In addition, an inspection apparatus for photographing the structure of the solid angle solder from an oblique direction has also been proposed. For example, in the case of illuminating the welded portion of the guide pin assembly, the welded portion is photographed from obliquely above, and one inspection target portion is photographed from a plurality of orientations, and the brightness of the image generated by each shot is used. The method of comparing the regional morphology with the corresponding threshold value to determine the quality of the welding.

In addition, in recent years, an inspection apparatus has been installed in each step of a series of processes performed to produce a substrate, and an inspection system that uses the measurement results performed in the previous process inspection for inspection in subsequent processes has also been developed. As an example of such a system, Patent Document 3 discloses that inspection apparatuses each having a three-dimensional measurement function are disposed in a solder printing process, a component mounting process, and a reflow process, and each inspection device is configured to be communicable system. Further, Patent Document 3 also describes that each of the inspection apparatuses inputs measurement data derived from the inspection of the previous process, and uses the measurement data to obtain a portion added to the process of the own device, or The amount of change in height in the portion where the change occurs is checked by a method of comparing the amount of change with the reference value.

Specifically, in the inspection after the component mounting described in Patent Document 3, the height of the cream solder is measured, and the height data of the cream solder measured by the inspection device of the solder printing process is obtained. The measured data is used to determine the amount of change in the height of the cream solder to determine the appropriateness of the amount of pressing of the component during installation. Further, in the inspection device after the solder printing, the height of the component is measured, and the height data of the component measured by the inspection device of the component mounting process is also obtained, and the amount of change in the height of the component is obtained by measuring the data from both sides. In order to discern whether the component has a bad floating condition.

Prior technical literature Patent literature

Patent Document 1 Japanese Patent No. 3590032

Patent Document 2 Japanese Patent Laid-Open Publication No. 2004-151010

Patent Document 3 Japanese Patent Laid-Open Publication No. 2007-78533

When the angle of the solid angle solder is steep, it is difficult to image the specular reflection from the fillet on the imaging surface of the camera, and the corresponding position in the image. Will become a dark area. In particular, for very small joints of the land, the fillet becomes very steep, and almost all of the solid corners form dark areas in the image, making it difficult to discern the state of adhesion.

On the other hand, according to the method of photographing the solid corner material from the oblique direction described in Patent Document 2, it is considered that the vicinity of the end point of the adhesion can be imaged regardless of the tilt state. However, in the actual image, it is difficult to distinguish the side of the component from the solid corner, and it is not easy to determine the location of the solder. Moreover, in recent years, the mounting density of the substrate is high, and when photographing from an oblique direction, there is a component that is hidden in the trace of other components and is difficult to photograph, and all components are photographed from a direction suitable for measurement of the solid angle material, and impossible.

Moreover, in the guide element assembly, the back fillet is fully adhered, although it is an important factor in determining the quality of the weld, but the rear solid corner material It will be concealed due to the component electrodes or the front fillet, so it is difficult to take pictures directly.

The present invention has been made in view of the above problems, and it has been a problem to be able to discriminate a state of solder adhesion in a welded portion including a portion having difficulty in appearance measurement.

In the inspection method of the present invention, the state of solder adhesion in the substrate is inspected by using an automatic visual inspection device having an imaging unit that is disposed on the substrate surface of the component mounting substrate from the front side. The upper part and the illumination part illuminate the subject area of the imaging unit. In this method, the amount of cream solder applied to the lands on the substrate in a solder printing process in a series of steps for mounting the substrate for the production of the component is performed before each component is mounted. Make measurements. Further, the automatic visual inspection device has the feature that is not displayed in the image generated by the imaging unit, and performs the following measurement on the welded portion in which the amount of the cream solder measured by the corresponding lands is in accordance with a predetermined good condition. Steps and decision steps.

In the measurement step, the features appearing in the image generated by the imaging unit are measured, and the features related to the shape of the position not shown in the image of the welded portion of the inspection object are measured. In the determining step, based on the measurement result obtained by the borrowing measurement step, it is determined whether or not the solder adhesion of the welded portion having the feature not appearing in the image is good or not.

According to the above method, although the amount of the cream solder before the formation of the solid angle solder is good, the adhesion of the solder is poor due to some factors, and even if the defect cannot be directly confirmed from the image, it can be used in the image. Characteristics of other parts in the middle to detect defects.

Specifically, for the assembly having the shape of the electrode on the side like the wafer assembly, when the above method is used for the welded portion, the measured value of the amount of the cream solder in the corresponding lands can exceed a predetermined reference value. The welded parts are subjected to the above steps. In the measurement step in this case, the height of the object component is measured. Further, in the determining step, when the difference between the measured value of the component height obtained by the measuring step and the reference height recorded for the component does not exceed the predetermined allowable value, it is determined that the solder of the welded portion of the inspection object is well adhered. When the difference in height exceeds the allowable value, it is determined that the soldering portion of the inspection target has poor solder adhesion.

In the above, the difference between the component height measurement value and the reference height is a parameter indicating that the component floats. The floating of the component is caused by the molten solder flowing into the lower part of the assembly when the cream solder is melted in the reflow process. If the inflow amount is large, the amount of solder connecting the electrode of the module and the land is less, so the solder The state of adhesion has also deteriorated.

In the present invention, according to this phenomenon, when the amount of the cream solder exceeds the reference value and the floating amount of the component does not exceed the allowable value, it is determined that the solder adheres well; although the amount of the cream solder exceeds the reference value, the float of the component When the amount of the amount exceeds the allowable value, it is determined that the solder is poorly adhered.

According to this method, even if the welded portion of the inspection object becomes a dark region, it is possible to correctly distinguish whether the darkness is caused by the steepness of the solid angle or the shape of the solid corner.

Further, in the automatic visual inspection device, before the determination step, the input step of inputting the measurement value of the amount of the cream solder in the lands corresponding to the welded portion of the inspection target from the outside may be performed. At this time, in the determining step, the value of the allowable value can be changed by the measured value input in accordance with the input step, thereby improving the accuracy of the determination.

Next, when the above method is used for each electrode welding portion to be mounted on the lead member of the substrate, the above steps are performed for the welded portion whose measured amount of the cream solder exceeds a predetermined reference value. In the measuring step of this case, the front solid image of the welded portion of the inspection object is subjected to a treatment to measure the amount of solder used to form the front solid corner. Further, in the determination step, when the measured value obtained by the measuring step is included in the range of the predetermined reference, it is determined that the soldering portion of the welded portion to be inspected is well adhered; when the measured value is not included in the reference range, the determination is made. Poor solder adhesion to the soldered portion of the inspection object.

In the past, in the visual inspection of the guide pin assembly, only the front solid corner material was used as the measurement object, the front solid corner material was formed well, and the cream solder applied to the lands was even if it was an appropriate amount, and most of it was solidified. On the electrode surface side, the rear solid corners become poor. Conversely, if most of the cream solder is solidified on the back side of the electrode, the front solid material becomes defective.

In the present invention, when the amount of the cream solder exceeds the reference value and the amount of the solder forming the front solid material exceeds the reference range or falls below the reference range, it is determined that the adhesion of the solder is poor. In this way, the determination of the state of the back solid material which is difficult to confirm from the image can be added, and the accuracy of the inspection can be improved.

In the inspection for the guide member, the input step of inputting the measurement value of the amount of the cream solder in the lands corresponding to the welded portion of the inspection object is performed before the determination step, and the reaction step can be performed in the determination step. Enter the measured value entered in the step to change the reference range. According to this method, the accuracy of the determination can be improved by changing the reference for determining the quality of the solder applied to the lands.

Further, the measurement of the amount of the cream solder can be performed, for example, in an inspection apparatus for inspecting the state of solder printing, but is not limited thereto, and in the component mounting process, before the component is mounted on the substrate introduced into the process, Measurement of cream solder.

Further, as a method of measuring the amount of the cream solder, the height of the cream solder applied to the land can be determined by, for example, a light cutting method or a phase shift method, and the method of accumulating the height can be used. Find the volume of the cream solder. However, the present invention is not limited thereto, and the application area of the cream solder may be detected by binarization of the image, and the area (number of pixels) of the detected area may be multiplied by the mask for solder printing. The method of thickness is used to obtain a value indicating the volume of the cream solder. Further, the area of the solder application region may be used as a parameter indicating the amount of solder.

The measurement step in the automatic visual inspection device may use the phase difference migration method or the stereo measurement to obtain the three-dimensional data of the measurement target portion, but the measurement method is not limited to the three-dimensional measurement. .

The automatic visual inspection device according to the present invention includes an imaging unit that is disposed above the substrate in a state in which the substrate surface of the component mounting substrate is viewed from the front, an illumination unit that illuminates an imaging region of the imaging unit, and a processing unit that uses The solder adhesion state on the substrate is checked by the image generated by the imaging unit.

The processing unit includes: a measuring means for a soldering portion having a feature that is not displayed in the image generated by the image capturing portion, and a feature that appears in the image and a shape that is not present in the image of the soldering portion The characteristic of the relationship is measured; the determining means uses the measurement data obtained by the method of the borrowing measurement to determine that the image has not appeared. The solder joint of the characteristic soldering portion is good or not; and the output means outputs the inspection result information according to the determination result.

According to the above configuration, it is possible to provide an automatic visual inspection device that meets the execution requirements of the aforementioned inspection method. According to the device, it is possible to determine whether or not the solder adhering state including the position of the unapplied feature in the image is judged, and the accuracy of the inspection is greatly improved.

In one embodiment of the automatic visual inspection device, there is provided an input means for appropriately measuring a measured value of the cream solder applied to the lands corresponding to the welded portion of the inspection target or the measured value. The result of the judgment result is input from the outside. Further, the determination means determines whether or not the amount of the cream solder measured by the land corresponding to the welded portion of the inspection target meets a predetermined good condition based on the information input from the input means. On the other hand, when it is determined that the condition is met, the measurement data is used for the determination, and when it is determined that the condition is not met, the solder adhesion state of the welded portion to be inspected is determined to be defective.

According to the above-described embodiment, even if the substrate having the lands having the cream solder coating amount is not removed and the production line is operated in the previous step, the welded portion of the lands in which the coating amount is not good can be determined as bad.

In the substrate inspection system of the present invention, the first automatic visual inspection device is provided in a solder printing process in a series of steps for producing a component mounting substrate, and is used for inspecting each of the lands of the substrate after solder printing. The second automatic visual inspection device is provided in a reflow process in a series of processes for inspecting the solder adhesion state of the component mounting substrate in the reflow process. Automatic appearance The inspection device includes an imaging unit that is disposed above the substrate in a state in which the substrate surface of the inspection target substrate is viewed from the front, an illumination unit that illuminates the imaging target region of the imaging unit, and a processing unit that is generated by using the imaging unit The image is used to perform the inspection.

The processing unit of the first automatic visual inspection device includes a measuring means for measuring the amount of cream solder applied to the lands to be inspected, and a determining means for measuring the amount of the cream solder and the basis of the pre-recording The value is compared to determine whether the amount of the cream solder is appropriate or not; and the output means outputs the inspection result information based on the determination result.

The processing unit of the second automatic visual inspection device includes an input means for checking the result of the inspection of the corresponding land of the welded portion having the feature that is not displayed in the image generated by the image capturing unit, and the first automatic visual inspection device. Or inputting communication between devices that output the output means of the first automatic visual inspection device; and the measuring means for the welded portion having the features that are not displayed in the image will be the features appearing in the image, and the welding The feature of the shape of the position that is not displayed in the image of the part is measured; the determining means is based on the information input by the input means, and is measured by the lands corresponding to the welded part having the unappeared feature in the image. Whether the amount of solder is determined according to a predetermined good condition, and the measurement data measured by the discrimination result and the measuring means is used to determine whether the solder adhesion state of the soldering portion having the feature not shown in the image is good or not; and the output means , the information of the inspection result based on the judgment result will be output.

In the above system, the second automatic visual inspection device can connect the first automatic visual inspection device to the welded portion having the features that are not displayed in the image. The result of the inspection of the corresponding lands of the bit or the measurement data is input, and the input information is used to discriminate whether the amount of the cream solder in the lands is in good condition. When it is discriminated that the amount of the cream solder is in good condition, the measured data can be measured according to the measuring means to determine whether the solder is adhered or not. On the other hand, when the measurement by the measurement means determines that the amount of the cream solder is not good, it is also possible to determine that the state of the solder adhesion is defective.

According to the present invention, even in the case of a soldered portion which appears in an image in a dark area or which is in a position which cannot be directly measured due to difficulty in photographing, the accuracy in checking the state of solder adhesion with excellent precision can be improved.

10‧‧‧Solid printing inspection device

11‧‧‧Solder printing device

20‧‧‧Installation inspection device

21‧‧‧Installation device

30‧‧‧Reflow inspection device

31‧‧‧Reflow furnace

40‧‧‧Data management server

100, 300‧‧ ‧ Processing Department

101, 301‧‧‧ Platform Department

102, 302‧‧‧ camera

103, 303‧‧‧ projector

104, 304‧‧‧Check head

105, 305‧‧‧ Lighting devices

110, 310‧‧‧ CPU

111, 311‧‧‧ memory

112, 312‧‧ ‧ Inspector Head Control

113, 313‧‧ ‧Photo Processing Department

114, 314‧‧‧Projector Control Department

115, 315‧‧‧ Platform Control Department

116, 316‧‧‧Measurement Processing Department

117, 317‧‧‧Executive Inspection Department

118, 318‧‧‧Check data memory

119, 319‧‧‧ communication interface

120, 320‧‧‧ Operation Department

121, 321‧‧‧ Display Department

305a, 305b‧‧‧ Window Department

322‧‧‧Lighting Control Department

Fig. 1 is an explanatory view showing a configuration of a substrate inspection system and an overall configuration of a component mounting substrate production line.

Fig. 2 is a block diagram showing the configuration of a solder print inspection apparatus.

Figure 3 is a block diagram showing the construction of the post-reflow inspection device.

Fig. 4 (1) to (2) are graphs showing the influence of the difference in the width of the land on the shape of the solid material and the direction of reflection of the illumination light.

Figure 5 is a flow chart showing the procedure for determining the quality of the solid corners.

Fig. 6 (1) to (3) are diagrams schematically showing an example of the difference in the case of the determination processing of Fig. 5.

Fig. 7 is a view showing an example in which the determination criterion of Fig. 5 is not applied.

Figure 8 is a flow chart showing the overall procedure for post-reflow inspection.

Fig. 9 is a view schematically showing the relationship between the amount of cream solder and the allowable value of the amount of floating of the module.

Fig. 10 is a graph showing the relationship between the amount of cream solder and the allowable value of the amount of floating of the component.

Fig. 11 (1) to (3) are diagrams schematically showing an example of good and bad solid corners in the lead assembly.

Figure 12 is a flow chart showing the procedure for determining the goodness of the solid corner material in the lead assembly.

[Embodiment of the Invention]

Fig. 1 is a view showing a configuration of a substrate inspection system according to an embodiment and an overall configuration of a production line of a component mounting substrate.

The production line of this embodiment includes a solder printing process, a component mounting process, and a reflow process. The solder printing process includes a solder printing apparatus 11 for applying a cream solder to each land on a substrate, and a solder print inspection apparatus 10 for inspecting a coated state of the cream solder. The component mounting process includes a mounter 21 for mounting the component on the substrate after solder printing, and a mount inspection device 20 for inspecting the mounted state of the component. The reflow process includes: a reflow furnace 31 for melting the cream solder on the substrate after the assembly is mounted, and a post-reflow inspection device 30 for checking the state of the solid angle solder or the component on the substrate after reflowing .

Each of the inspection devices 10, 20, and 30 is an automatic visual inspection device and is connected to each other through a LAN return line 100.

Further, the LAN management line 40 is connected to the LAN return line 100. The server 40 stores the inspection devices 10, 20, and 30 for inspection. The inspection reference data and inspection result information used. The inspection reference data includes the program required for inspection, the judgment reference value, and the like. The inspection result information includes the measurement result or the result of the determination based on the measurement processing of the inspection target portion.

Each of the inspection apparatuses 10, 20, and 30 reads the required inspection reference data from the server 40, generates an inspection program for the target substrate inspection, and photographs the substrate according to the program, and presses each of the corresponding components. The range performs measurement and determination. The inspection result information obtained by the processing is connected to the identification information of the substrate and the component, and transmitted to the server 40 for storage in the memory.

Further, the inspection result information of the solder print inspection apparatus 10 can also be read by each of the lands. The solid angle inspection result and the measurement data of the post-reflow inspection device 30 are also set to be readable by each electrode.

According to the inspection result information of the above-described configuration, in the solid corner inspection of the post-reflow inspection apparatus 30, the solder print inspection apparatus 10 obtains the inspection of the land corresponding to the welding portion to be inspected. The obtained inspection result information is checked and the inspection result information is one of the determination targets. In this embodiment, the data management server 40 is accessed by the post-reflow inspection device 30 to obtain inspection result information of the platter to be processed. However, the present invention is not limited to this type, and communication with the solder print inspection apparatus 10 may be used to obtain necessary inspection result information.

The contents of the device configuration and processing relating to the inspection will be described below in order.

Fig. 2 shows the configuration of the solder print inspection apparatus 10.

The solder print inspection apparatus 10 of this embodiment is provided with a platform portion 101 for supporting a substrate to be inspected, a camera 102, a projector 103, and an inspection head 104 that is supported above the platform portion 101; and processing Department 100. The platform unit 101 is provided with a moving mechanism (not shown) that moves the platform body along an axis (for example, an axis in the left-right direction in FIG. 2). The inspection head 104 is provided with a moving mechanism (not shown) that moves the inspection head main body together with the camera 102 and the projector 103 along an axis orthogonal to the movement axis of the platform unit 101. Further, the inspection head 104 is also provided with an illumination unit for illuminating the imaging target area of the camera 102, but is not shown in FIG.

In addition to the above-described operation control of the moving mechanism and the optical system, the processing unit 100 also performs processing such as measurement, determination, and output of results, and thus includes the CPU 110, the memory 111, the inspection head control unit 112, the imaging processing unit 113, and The projector control unit 114, the platform control unit 115, the measurement processing unit 116, the execution inspection unit 117, the inspection data storage unit 118, the communication interface 119, the operation unit 120, the display unit 121, and the like.

The CPU 110 controls the movement of the inspection head 104 and the platform unit 101 via the inspection head control unit 112 and the platform control unit 115, and causes the camera 102 to perform imaging via the imaging processing unit 113, and causes the projector 103 to project via the projector control unit 114. deal with. Further, the imaging processing unit 113 is also provided with a function of inputting a video generated by the camera 102 and performing digital conversion.

The memory 111 stores, in addition to the program for the above control, image data generated by the digital conversion by the image processing unit 113, a projection image to be projected by the projector 103, and the like.

The measurement processing unit 116 and the execution inspection unit 117 are programmable logic devices, and cooperate with the CPU 110 to perform measurement and determination processing.

In the solder print inspection apparatus 10 having the above configuration, according to the principle of the phase shift method, the lands on the substrate are projected from the projector 103 by the stripe pattern image which periodically changes, and the pattern image changes every time. Take a picture. The measurement processing unit 116 detects a change in image brightness generated during a projection process of one cycle for each pixel, and calculates a height of a dot displayed by the pixel based on the phase of the change.

Further, the measurement processing unit 116 regards the pixel whose calculated height exceeds a predetermined value as the display of the cream solder, and integrates the heights of the pixels to obtain the volume of the cream solder on the land. . The execution inspection unit 117 compares the volume with a predetermined reference value. When the volume is equal to or greater than the reference value, it is determined that the coating amount of the cream solder is good. If the volume is less than the reference value, the cream is determined to be a cream solder. Poor coating amount.

The CPU 110 integrates the determination result and the measurement value for determining the solder volume into inspection result information constituting the data, and stores it in the inspection data storage unit 118. Further, each time the inspection of one substrate is completed, the information stored for the substrate is collected and transmitted to the server 40 via the communication interface 119.

Fig. 3 is a view showing the configuration of the post-reflow inspection device 30.

The post-reflow inspection device 30 also has a substrate platform 301, a camera 302, a projector 303 and an inspection head 304, and a processing unit 300. The processing unit 300 also has the same configuration as the processing unit 100 of the solder print inspection device 10 of FIG. 2, so the post-digit two-digit number and the solder print check are attached to each configuration. The symbols corresponding to the configuration of the device 10 (for example, the CPU 310 for the CP U110) are omitted, and the description thereof is omitted.

In the configuration that is not present in the solder print inspection apparatus 10, the post-reflow inspection apparatus 30 is provided with a dome type illumination device 305 as an illumination unit. Further, the processing unit 300 is also provided with an illumination control unit 322 for controlling the lighting operation of the illumination device 305.

The illumination device 305 is also mounted to the inspection head 304, but is supported at a lower position than the camera 302 or projector 303. The position of the ceiling camera 302 or the projector 303 of the illumination device 305 is provided with window portions 305a and 305b for imaging and projection, respectively. LEDs (not shown) are arranged in an annular shape over substantially the entire inner surface of the ceiling outside the window portions 305a and 305b. The color of the light emitted by the LEDs changes slowly according to the change in the azimuth angle and the incident angle, and is adjusted so as to become white light when the light of each color diffuses.

In the post-reflow inspection apparatus 30 having the above-described configuration, similarly to the solder print inspection apparatus 10, a plurality of shots are taken in accordance with the projection of the stripe pattern image from the projector 303, and the height of the image generated by each shot is used. Measure. This height measurement is implemented for a range corresponding to the component, whereby the three-dimensional shape of the component is restored.

Further, in the post-reflow inspection device 30, the illumination is performed under the illumination of the illumination device 305 (hereinafter referred to as "dome illumination"), and the color of the specular reflection image of the welded portion appearing in the image is displayed. And the direction of illumination corresponding to the color of the light to determine the surface normal direction of the pixel produced by the color. Further using the combination of the coordinates of the determined pixel and the normal vector to make the three-dimensional shape of the solder Originally, by analyzing the relationship between the three-dimensional shape and the three-dimensional shape of the component, it is determined whether the solder is well wetted to the electrode of the module.

Further, the measurement processing unit 316 includes a table in which characteristic data representing a color and a correspondence relationship with a normal direction estimated by the light of the color are recorded, and the feature data detected by the image is used. Check the form to quickly determine the direction of the normal.

However, the camera 302 of the post-reflow inspection apparatus 30 is disposed so as to photograph the substrate from substantially right above. If the inclination of the solid angle solder is steep, it is difficult for the regular reflection light from the solid angle material to enter the camera.

Fig. 4 shows an example in which the wafer assembly is used as an example to change the inclination angle of the solid angle material or the reflection direction of the illumination light depending on the size of the land to be welded. Further, in Fig. 4 and Figs. 6, 7, and 9 to be described later, only the state in which the one-side electrode of the wafer unit is welded is shown for simplification.

When soldering to a standard-sized lands, as shown in (1) of Fig. 4, the solid corners are relatively gentle, and the illumination light from the oblique direction can be reflected toward the direction of the camera 302. However, when the width of the land to be welded is narrow, the inclination of the solid material becomes steep, so that the illumination light cannot be reflected in the direction of the camera 302 as shown in (2) of Fig. 4 . As a result, the position corresponding to the solid corner material in the image becomes a dark area, and the three-dimensional shape of the solder cannot be restored, and the inspection with excellent accuracy cannot be performed.

In view of the above problems, in the post-reflow inspection of the present embodiment, for the solder joint where the color distribution is not clear, the result of the solder print inspection for the corresponding land of the portion is input, and the component measured from the self device is input. The amount of floating of the component is calculated by the height, and the processing shown in Fig. 5 is used to determine whether the solid angle is good or not.

In this determination process, the result of checking the solder print inspection is "good" or "poor" (step A). Moreover, if the result is "good", it is checked whether the floating amount of the component is within the allowable value (step B).

Fig. 6 shows a three example of the case division using the wafer assembly as an example, using the above steps A and B.

Each of the examples is applied to the cream state of the substrate before the component is mounted, and the state of the solid filler formed by the melting and solidification of the cream solder is displayed side by side. Moreover, in the figure on the right hand side, the adhesion range of the solder to the component electrodes is represented by a line with an arrow.

In the example of (1) of Fig. 6, the appropriate amount of cream solder is adhered to the land, and the assembly is properly mounted on the land, and the solder is adhered to the upper portion of the electrode. In this case, the result of the solder print inspection is "good", and the floating amount of the component is within the allowable value. Therefore, steps A and B of Fig. 4 are both "YES", and the solid corners are judged to be good ( Step C).

In the example of (2) of Fig. 6, the amount of the cream solder is appropriate, but when the cream solder is melted, the assembly floats and a part of the solder flows under the assembly, thereby contributing to the formation of the solid corner material. The amount of solder is greatly reduced. Although the solder adheres to some extent, since the component moves to the upper side, the upper end position of the adhesion stays at the lower end of the component electrode.

In this case, although the result of the solder print inspection is "good", the floating amount of the component exceeds the allowable value, so that step A is "YES" and step B is "NO", so it can be determined that the solid corner material is defective ( Step D).

In the example of (3) of Fig. 6, since the amount of the cream solder applied to the land is less than the reference amount, the adhesion of the solder is poor. In this case, the result of the solder print inspection is "poor", step A That is, if it is "NO", the amount of floating of the component is not checked, and the process proceeds directly to step D, and it is determined that the solid waste is defective.

As shown in (2) and (3) of Fig. 6, in the case where the amount of the cream solder is small or the case where the module is floated, the adhesion state of the solder is insufficient, and the solid corner material becomes short. However, when the lands are narrow, even if the length of the gusset becomes short, the inclination becomes steep, so even in the examples of (2) and (3) of Fig. 6, and Fig. 6 ( The example of 1) is the same, it is possible that the color distribution of the solid corner does not occur in the image. In this case, it is difficult to distinguish the examples of (1), (2), and (3) of Fig. 6 from the image.

On the other hand, according to the decision interpretation method shown in FIG. 5, it is possible to determine the amount of the cream solder applied in the lands before the component is mounted and the amount of the component float in the substrate after the reflow. Differentiate each instance and correctly determine whether the solid angle is good or not.

However, the determination process of Fig. 5 is used because the specular reflection light from the light from the ceiling type illumination device 305 cannot be guided to the camera 302, so that the corresponding position in the image is limited to the welded portion which becomes the dark region. For the welded portion where the dark region is not generated, the above-described interpretation method based on the relationship between the three-dimensional shape of the solder and the three-dimensional shape of the component is used. By clearly separating the interpretation processing of the processing in this manner, it is possible to prevent the solder having the shape shown in Fig. 7 from being judged to be good.

In the example of Fig. 7, the amount of solder of the cream solder is appropriate, and the floating of the component does not occur, but for some reasons (for example, the temperature of the reflow furnace is low), the solder does not wet and consolidate. Ball-shaped. When the determination process of Figure 5 is used for solder of this type, solid corners are made. For good judgment, the situation is not good. However, the solder of the example of Fig. 7 is inclined and gentle, and the specular reflected light for the illumination light is guided to the camera 302. The corresponding position in the image under the ceiling illumination produces a color distribution of the illumination light, so It is the applicable external condition of the judgment processing of the fifth figure.

Therefore, it is possible to accurately determine the shape of the solid corner material by the three-dimensional shape restored from the color distribution.

Fig. 8 shows a specific procedure of the inspection performed in the inspection device 30 after the reflow.

This processing allows the inspection target substrate to be moved into the platform portion 301, and the alignment of the inspection head 304 is completed. First, in step S1, in order to obtain the component height measurement image, a predetermined number of times of shooting is performed using the projection of the pattern image provided by the projector 303. In step S2, in order to obtain the image for solder measurement, shooting is also performed under ceiling lighting.

The plurality of frame images obtained by each of the steps S1 and S2 are stored in the memory 311. Each of the photographing is performed while the camera 302 is positioned at a specific location, and thus the relationship of the position or arrangement of the components included in the images is integrated.

The following focuses on the components included in the image, and performs the following processing for each component.

First, a window for inspection is set for the component in focus (step S3). The window to be set differs depending on the type of component, but generally, a component window including the component body and a land window for each soldering portion are set. These windows are also set to be common to the windows of the plurality of images described above.

In step S4, the height measurement is performed using the image data generated by the projection of the stripe pattern image as the object of each pixel in the component window. Further, by combining the coordinates of the pixels whose height is measured by a predetermined value or more and the calculated height, the three-dimensional shape of the module is restored.

In step S5, the dark area in the connection window of the component set in the eye is detected for the image under the illumination of the ceiling. In step S6, the ratio of the dark areas occupying the window in each of the lands is determined and compared with a predetermined threshold. Here, if there is only one connection window in which the ratio of the dark area exceeds the threshold, steps S7, S8, and S9 are executed.

In step S7, the result of the solder print inspection for the component in the eye is input from the data management server 40 or the solder print inspection device 10. In step S8, the amount of floating of the component is calculated based on the height data measured in step S4. Specifically, the average value or the maximum value of the height calculated for the component is used as the component height, and the difference between the height and the reference height recorded for the component in the eye is obtained, and the difference is the floating amount.

In step S9, the amount of solder input in step S7 and the amount of component floating calculated in step S8 are determined, and each of the connection trays is determined by performing the determination processing for the method shown in the previous fifth diagram for each of the connection trays. Whether the medium solid angle is good or not.

In step S6, when it is determined that the ratio of the dark areas of the respective connection trays is smaller than the threshold value, step S10 and step S11 are executed for each of the connection tray windows.

In step S10, the three-dimensional shape of the solder is restored by referring to the above-described table and replacing the color distribution in the connected disk window with the normal distribution.

In step S11, the analysis of the three-dimensional shape of the solder restored in the above step S10 and the three-dimensional shape of the component restored in step S4 is performed to determine whether the solid angle solder is good or not. For example, it is determined whether the solder contacts the side of the component from the relationship between the coordinates of the component and the coordinates representing the solder. When it is judged that there is contact, the heights of the contact portions are compared. Then, if the difference between the heights is within a predetermined threshold, it is determined that the solid corner material is good, and when the difference is greater than the threshold value, it is determined that the solid corner material is defective.

The result of the above processing is repeated for each component, and when the processing for all the components is completed (YES in step S12), the determination results of the respective components are integrated to determine whether or not the entire substrate is good (step S13). Next, in step S14, the inspection result information including the result of each determination and the measurement value is created, and is stored in the inspection data storage unit 318 and output to the data management server 40.

Further, according to the flowchart of FIG. 8, the processing of the platform portion 301 and the inspection head 304 is performed once because of the photographing, but when the substrate has a larger field of view than the camera 302, the steps S1 and S2 are repeated. The shooting is repeated with steps S3 to S12 in conjunction with the cycle of shooting.

Further, in step S9 (step B of Fig. 5), the allowable value for comparison with the amount of floating of the component is determined in advance by considering the height unevenness of the component. For example, the degree of height unevenness of such a component is obtained for each component type, and the allowable value derived from the unevenness value is used as inspection reference data, and is recorded.

If the floating tolerance of the component is not a certain value, but is changed in accordance with the amount (volume) of the cream solder, the accuracy of the determination can be further improved.

Fig. 9 is a view schematically showing the relationship between the amount of application of the cream solder and the allowable value of the amount of floating for discriminating the solid corner material. As shown in the figure, when the amount of the cream solder is large, the allowable value of the float can be increased to some extent, but the float allowable value must be reduced to the extent that the cream solder is reduced.

In order to change the floating allowable value in accordance with the amount of the cream solder, for example, a plurality of samples are used to determine the relationship between the two, and a table indicating the relationship is recorded in the post-reflow inspection device 30. Further, the volume of the cream solder measured in the inspection may be input to the post-weld inspection device 30 instead of the result of the input solder print inspection, and the allowable value may be estimated by referring to the above table based on the input value.

Fig. 10 is a graph in which the relationship between the volume of the cream solder and the allowable value of the floating of the component is replaced by a graph. P in the figure is the limit point at which the allowable value can be set. When the amount of the cream solder is less than the amount indicated by the point P, the solid corner defect occurs regardless of the presence or absence of the floating of the component.

In Fig. 10, the dot value (dot) is used to indicate the allowable value derived from the sample and recorded in the table. When the volume measurement value of the cream solder is larger than the value indicated by the point P, the point P corresponding to the measurement value in the graph is selected as the allowable value indicated by the dot at the highest position in the small range. It is sufficient to compare the allowable value of the selection with the offset of the component. When the amount of solder is below the point P, it can be unconditionally determined that the solid corner material is defective, and the offset of the component is not measured.

As described above, in this embodiment, the soldering portion indicating that the feature of the solder does not appear in the illumination of the ceiling can be based on characteristics belonging to other features appearing in the image and related to the shape of the soldering portion (component height) And the amount of cream solder applied to the land corresponding to the welded portion, and the adhesion state of the solder is judged with good precision.

Further, the post-reflow inspection using the result of the solder print inspection is not limited to the above, and the inspection of the welded portion of the lead guide assembly is also applicable.

In the soldering of the lead pin assembly, it is preferable to apply a corresponding amount of solder to both the surface side and the back side of the electrode. (1) of Fig. 11 is an example of the ideal welding, and (2) and (3) of Fig. 11 show a non-good welding example.

If an appropriate amount of cream solder is applied to the lands, the solder melted by the reflow process is evenly distributed on the surface and the back surface of the electrode, as shown in (1) of FIG. 11 , the front solid corner and the rear solid corner Can be formed very well.

On the other hand, when the amount of the cream solder applied to the land is small, the molten solder adheres to the surface side, and as shown in Fig. 11 (2), it becomes a state in which the good back corner is not formed. The situation. Further, conversely, the solder is concentrated on the back side of the electrode, and as shown in (3) of Fig. 11, there is a problem that the front cleat cannot be normally adhered.

Further, even if the amount of the cream solder is an appropriate amount, there is a possibility that it is inferior to the (2) of Fig. 11 or the (3) of Fig. 11 due to the coating state.

As described above, in the post-reflow inspection apparatus 30 of this embodiment, since the substrate is photographed from substantially directly above, in the generated image, although the front solid corner material can be measured, the rear solid corner material is almost photographed. It is impossible to measure. Therefore, in the embodiment shown below, the volume of the surface side solder is obtained by measuring the height of the front solid corner material, and according to the volume and the inspection result of the solder printing inspection, the implementation includes the identification of the rear solid corner material. Check inside.

Figure 12 shows the procedure for performing the above checks on one of the electrodes of the lead assembly. This program is also implemented as the processing in step S9 of Fig. 8.

Hereinafter, the determination of the state of adhesion of the solder in the lead leg assembly will be described with reference to the step symbols of the flowchart.

First, the inspection result of the solder print inspection is input to the land corresponding to the inspection target electrode, and the result of the result is discriminated (steps S21 and S22). In this embodiment, the solder volume value considered to be the minimum necessary limit is added to the front side and the back side of the electrode of the lead leg assembly as the reference value for determining whether or not the solder print inspection is good. Therefore, when the solder print inspection is judged to be "defective" ("NO" in step S22), it is apparent that the solder is insufficient. Therefore, the process proceeds to step S27, where it is determined that the solid corner material is defective, and the image is not measured using the ceiling illumination. .

When the result of the solder print inspection of the corresponding land is "good" ("YES" in step S22), the process proceeds to step S23, and the color distribution of the illumination color in the corresponding connection window is measured using the image under the ceiling illumination. The height of the position (equivalent to the front solid). Further, the calculation for calculating the sum of the measured values of the respective heights is used to form the front The solder volume of the solid material (step S24) is compared with the range of the predetermined reference (step S25).

In the solder print inspection, when the coating amount of the cream solder is equal to or higher than the reference value, it is judged to be good, and when the solder volume on the surface side is included in the reference range ("YES" in both step S22 and step S25), the front solid corner material and The rear solid corners are regarded as good, and the judgment is "good" (step S26). On the other hand, when the coating amount of the cream solder is equal to or higher than the reference value, the solder volume on the surface side is increased when the solder is applied to the surface side, so that the solder volume calculated in step S24 is out of the reference range. Conversely, when the solder is biased to the back side of the electrode, the solder volume on the surface side is reduced, so the solder volume is lower than the reference range. In these cases, step S25 is "NO", so the process proceeds to step S27, and it is determined that the solid corner material is defective.

In addition, in this embodiment, in step S21, the cream solder volume measured by the inspection may be input to replace the input of the solder print inspection result, and the reference for the determination of step S25 is changed according to the volume. range. For example, as the amount of application of the cream solder increases, the upper limit value indicating the reference range is increased, and the lower limit value indicating the reference range is lowered, so that the state that can be determined not to be defective can be prevented from being determined to be defective.

As described above, when only the image under the illumination of the ceiling is processed, the inspection can be performed only according to the shape of the front solid material, and if the determination processing shown in Fig. 12 is performed, the state of the solid content can be performed. The inspection is judged, and the quality of the welding can be correctly determined.

Further, in the above-described embodiment, even if the substrate which is determined to have a poor solder coating amount in the solder print inspection is subjected to the processing of the subsequent process, the result of the solder print inspection is input, but When the amount of solder coating is poor, the substrate is removed, and when the substrate that is judged to be good is transferred to the subsequent process, the input of the solder print inspection result is not necessarily required. For example, in the flowchart of Fig. 8, the step S7 may be omitted, and only the step S9 may be determined based on the amount of floating of the component (i.e., the determination process of step A of Fig. 5 is removed). Further, in the determination process for the lead leg assembly shown in Fig. 12, the steps S21 and S22 are not performed, and the volume of the surface side solder for forming the front solid material is determined, and the volume and the reference range can be determined. Control the procedure to determine the goodness of the solid corners.

However, in order to improve the accuracy of the determination, the cream solder volume measured by the solder print inspection may be input, and the reference value used for the determination of step S9 or step S25 may be changed according to the value of the volume.

30‧‧‧Reflow inspection device

300‧‧‧Processing Department

301‧‧‧ Platform Department

302‧‧‧ camera

303‧‧‧Projector

304‧‧‧Check head

305‧‧‧Lighting device

305a, 305b‧‧‧ Window Department

310‧‧‧CPU

311‧‧‧ memory

312‧‧‧Inspector Head Control

313‧‧‧Photo Processing Department

314‧‧‧Projector Control Department

315‧‧‧ Platform Control Department

316‧‧‧Measurement Processing Department

317‧‧‧Executive Inspection Department

318‧‧‧Check data memory

319‧‧‧Communication interface

320‧‧‧Operation Department

321‧‧‧Display Department

322‧‧‧Lighting Control Department

Claims (8)

A method of inspecting a state of adhesion of a solder is a method of inspecting a state of solder adhesion of a substrate by using an automatic visual inspection device having an imaging portion for observing a state of a substrate surface of a component mounting substrate from the front side And an illumination unit that illuminates a region to be photographed of the imaging unit, and is characterized in that the solder printing process in one of the series of steps for mounting the component mounting substrate is applied to The amount of cream solder on the lands on the substrate is measured for each splicing plate before the assembly is mounted. In the automatic visual inspection device described above, the following steps are performed: the measuring step is performed for the photographic portion The features that are not displayed in the generated image, the solder joints whose amount of cream solder measured according to the corresponding lands are in accordance with predetermined good conditions, will belong to the features appearing in the image generated by the image capturing unit, and The shape of the position in the welded portion where the image is not present is related to the measurement, the determining step, according to the measuring step The amount of the obtained measurement results to determine the welded portion of the solder buildup of the good or bad. The method for inspecting the state of adhesion of the solder according to the first aspect of the invention, wherein the welding portion of the component having the shape of the electrode on the side surface is the welding value of the amount of the cream solder exceeding a predetermined reference value a portion, performing the foregoing steps, wherein the measuring step measures the height of the component, In the determining step, when the difference between the component height measurement value obtained by the measuring step and the reference height recorded on the component does not exceed a predetermined allowable value, it is determined that the solder in the welded portion to be inspected is well adhered. When the difference in height exceeds the allowable value, it is determined that the solder adhesion in the welded portion to be inspected is defective. In the method of inspecting the state of adhesion of the solder according to the second aspect of the invention, in the automatic visual inspection device, before the determining step, the connection between the externally input and the welded portion of the inspection target is performed first. In the step of inputting the measured value of the amount of the cream solder, in the determining step, the allowable value is changed in accordance with the measured value input in the input step. The method for inspecting the state of adhesion of the solder according to the first aspect of the patent application, wherein the soldering portion to be attached to each of the electrodes of the lead member of the substrate is a measurement value of the amount of the cream solder exceeding a predetermined value Performing the above steps in the welding portion of the determined reference value, in the measuring step, applying an image of the front solid material of the welded portion of the inspection object, and measuring the solder for forming the front solid material In the determining step, when the measured value obtained by the measuring step is included in a predetermined reference range, it is determined that the soldering portion of the welded portion to be inspected is well adhered, and when the measured value is not included in the reference range, Then, it is determined that the soldering portion of the inspection target has poor solder adhesion. The method for inspecting the adhesion state of the solder according to item 4 of the patent application, wherein In the automatic visual inspection device, before the determination step, an input step of inputting a measurement value of the amount of the cream solder in the lands corresponding to the welded portion of the inspection target is externally input, and the determination step is performed in accordance with the determination step. The measurement value input by the aforementioned input step changes the range of the aforementioned reference. An automatic visual inspection device includes: an imaging unit that is disposed above a substrate when a substrate surface of a component mounting substrate is viewed from a front side; an illumination unit that illuminates an imaging target region of the imaging unit; and a processing unit The soldering state on the substrate is inspected by using an image generated by the image capturing unit, and the processing unit includes a measuring means for the soldering portion having a feature that is not displayed in the image generated by the image capturing unit a feature that appears in the image, and is characterized by a feature that is related to a shape of the welded portion that is not present at the position of the image; and the determining means uses the measurement data obtained by the processing of the measuring means to The solder adhesion state of the soldered portion having the feature not found in the image generated by the image capturing unit is judged to be good or not; and the output means outputs the inspection result information based on the determination result. The automatic visual inspection device according to the sixth aspect of the invention, further comprising an input means for inputting an amount of the cream solder applied on the land corresponding to the welded portion of the inspection object from the outside. Information on the results of the measurement or the appropriateness of the measurement, The determining means determines whether the amount of the cream solder measured by the corresponding land of the welded portion having the feature not shown in the image generated by the image capturing unit is in accordance with the predetermined information based on the information input from the input means. When the condition is determined to be in accordance with the condition, the measurement is performed using the above-described measurement data, and when it is determined that the condition is not met, it is determined that the solder adhesion state of the welded portion is defective. A substrate inspection system comprising: a first automatic visual inspection device, which is provided in a solder printing process in a series of steps for producing a component mounting substrate, to check a cream solder coating in each of the lands of the substrate after solder printing And a second automatic visual inspection device provided in the reflow process in the series of processes to check the state of solder adhesion on the component mounting substrate after the reflow process, and each of the automatic visual inspection devices includes: The portion is disposed above the substrate in a state in which the substrate surface of the substrate to be inspected is viewed from the front; the illumination portion illuminates the imaging target region of the imaging portion; and the processing portion uses the image generated by the imaging portion In the inspection, the processing unit of the first automatic visual inspection device includes a measuring means for measuring the amount of cream solder applied to the lands of the inspection target, and a determining means for measuring the amount of the cream solder Compare with the pre-recorded reference value to determine whether the amount of solder is appropriate or not; and the output means, according to the result of the foregoing determination, the result of the inspection In the output, the processing unit of the second automatic visual inspection device includes: an input means for displaying the inspection result information of the corresponding land of the welded portion having the feature not shown in the image generated by the imaging unit, and the first automatic Inputting communication of the receiving device of the output of the visual inspection device or the output means of the first automatic visual inspection device; Measuring means for measuring a feature having a feature appearing in the image and having a relationship with a position at which the image in the welded portion is not present, for the welded portion having the feature not shown in the image; And determining, according to the information input by the input means, the amount of the cream solder measured by the corresponding land of the welded portion having the feature not shown in the image, whether the predetermined condition is met, and using the result of the discrimination And measuring the measurement data obtained by the measurement means to determine whether the solder joint having the feature not shown in the image is adhered to or not; and the output means outputting the inspection result information based on the result of the determination.