JP2024025687A - Inspection equipment and inspection method - Google Patents

Abstract

An object of the present invention is to provide an inspection method for accurately detecting a poorly connected wire while suppressing the influence on normal wires in wire bonding. A wire bonding inspection device connects a first component and a second component by connecting one end of the wire to the first member and the other end of the component wire to the second member, comprising: It includes a blowing means for blowing air to the wire bonding, an imaging means for taking an image of the wire bonding, and a control means, and the imaging means displays a blow ON image in a state where the constituent air is being blown by the constituent blowing means, and the constituent blowing means. The control means uses an inspection device that inspects poor connection of the component wires by capturing a blow OFF image in a state where component air is not blown, and by comparing the component blow ON image and the component blow OFF image. [Selection diagram] Figure 5

Description

The present invention relates to an inspection device and an inspection method.

Wire bonding, which uses metal wires such as gold or aluminum, is known as a method for electrically connecting electrodes on integrated circuits to electrodes on printed wiring boards or semiconductor packages. As a method for inspecting connection defects in wires used for bonding, Patent Document 1 discloses a method of inspecting wire connection conditions by blowing high-pressure air onto the wire connections to blow out the defective wire connections, and imaging the connection portions with an imaging device. A technique has been disclosed to automatically determine.

Japanese Patent Application Publication No. 6-224278

However, in the method described in Patent Document 1, if one end of the defective wire is connected normally and the other end is defective, the wire may not be blown away by high-pressure air, and the imaging device may fail. Unable to determine. Further, if the air pressure is increased further to blow off a wire that is normally connected at one end, there is a concern that it may have an adverse effect such as peeling off the connection portion of a good wire.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an inspection method for accurately detecting a poorly connected wire while suppressing the influence on normal wires in wire bonding.

The present invention employs the following configuration. That is,
A wire bonding inspection device that connects the first member and the second member by connecting one end of the wire to the first member and connecting the other end of the wire to the second member,
blowing means for blowing air to the wire bonding;
an imaging means for imaging the wire bonding;
control means;
Equipped with
The image capturing means captures a blow ON image in a state where the air is being blown by the blowing unit and a blow OFF image in a state where the air is not being blown by the blowing unit,
The inspection device is characterized in that the control means inspects for poor connection of the wire by comparing the blow ON image and the blow OFF image.

The present invention also employs the following configuration. That is,
A wire bonding inspection device that connects the first member and the second member by connecting one end of the wire to the first member and connecting the other end of the wire to the second member,
blowing means for blowing air to the wire bonding;
an imaging means for imaging the wire bonding;
control means;
Equipped with
The blowing means blows the air at a wind speed that causes the wire to vibrate when there is a poor connection between the wire and at least one of the first member and the second member,
The image capturing means captures an image in a state where the air is being blown,
The control means inspects whether or not there is a connection failure of the wire in the image based on an amplitude difference between the wire with the connection failure and the normally connected wire with respect to the air blowing. This is an inspection device.

The present invention also employs the following configuration. That is,
A wire bonding inspection method that connects the first member and the second member by connecting one end of the wire to a first member and the other end of the wire to a second member, the method comprising:
an imaging means imaging the wire bonding in a state where air is being blown by the blowing means to create a blow-on image;
the imaging means imaging the wire bonding in a state where the air is not being blown by the blowing means to create a blow-off image;
a step in which the control means inspects for poor connection of the wire by comparing the blow ON image and the blow OFF image;
This is an inspection method that has

The present invention also employs the following configuration. That is,
A wire bonding inspection method that connects the first member and the second member by connecting one end of the wire to a first member and the other end of the wire to a second member, the method comprising:
a step in which the imaging means captures an image in a state where air is being blown by the blowing means;
a step in which the control means inspects the presence or absence of a connection failure of the wire in the image based on an amplitude difference in relation to the air blowing between the wire with the connection failure and the normally connected wire;
has
The blowing means blows the air at such a wind speed that the wire vibrates when there is a poor connection between the wire and at least one of the first member and the second member. This is an inspection method that

According to the present invention, in wire bonding, it is possible to provide an inspection method that accurately detects a poorly connected wire while suppressing the influence on normal wires.

Schematic perspective view showing the configuration of a liquid ejection head A schematic plan view and a schematic cross-sectional view showing the wire bonding part of the liquid ejection head A schematic perspective view and a schematic plan view showing an example of bonding failure A schematic perspective view and a schematic plan view showing another example of bonding failure Schematic diagram of the inspection device of the first embodiment Block diagram of the inspection device of the first embodiment Flow diagram showing the inspection flow of the first embodiment Flow diagram showing the image processing flow of the first embodiment A schematic perspective view showing one step of the bonding wire inspection method of the first embodiment A schematic perspective view showing one step of the bonding wire inspection method of the first embodiment A schematic perspective view showing one step of the bonding wire inspection method of the first embodiment A schematic plan view of a captured image of a defective bonding wire according to the first embodiment Schematic diagram showing image processing of the first embodiment A diagram showing an example of bonding failure in the second embodiment Flow diagram showing the processing flow of the second embodiment Diagram explaining the bonding wire inspection method of the second embodiment Continuation of the diagram illustrating the bonding wire inspection method of the second embodiment Schematic diagram showing image processing of the second embodiment

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangement of the components described in the embodiments should be changed as appropriate depending on the configuration of the device to which the invention is applied, various conditions, etc. It is not intended to limit the scope to the following embodiments.

(First embodiment)
Hereinafter, embodiments to which the present invention can be applied will be described based on the drawings. Although a substrate used in a liquid ejection head of a recording device will be explained here as an example, the present invention is not limited thereto, and wire bonding in which one end of a wire is connected to a first member and the other end is connected to a second member is described. It is applicable to various substrates etc. Further, the wire bonding method to which the present invention is applied is not particularly limited, and can be applied to either ball bonding or wedge bonding, for example. The present invention can be understood as a wire bonding testing method and testing device.

FIG. 1 is a schematic perspective view showing one step of a method for manufacturing a liquid ejection head. FIG. 2 is an enlarged schematic diagram of section A in FIG. FIG. 2(a) is a schematic plan view from above. FIG. 2(b) is a schematic cross-sectional view taken along the line B-B' in FIG. 2(a), and also shows the positional relationship including height differences of the wires. 3(a) and 3(b) are a schematic perspective view and a schematic plan view showing an example of defective bonding in the section A of FIG. 1. FIG. FIGS. 4A and 4B are a schematic perspective view and a schematic plan view showing another example of bonding failure. FIG. 5 is a schematic diagram of an inspection device for determining defects in bonding wires. FIG. 6 is a functional block diagram of the inspection device. FIG. 7 is a flow diagram showing the inspection flow. FIG. 7 is a flow diagram showing the image processing flow.

In the following explanation, terms such as "upper", "lower", "higher", "lower", "horizontal", and "vertical" are used for convenience in explaining the configuration according to the drawings, and are used during inspection and The positional relationship when using the liquid ejection head is not limited. In the following description, the direction in which the FPC 14, PWB 16, etc. extend is assumed to be a horizontal plane. Furthermore, with the surface of the FPC 14 or PWB 16 as a reference, the side to which the wire 17 is connected is defined as the upper side. For example, when referring to the positional relationship of wires, a wire with a large distance from the surface of the FPC 14 or PWB 16 is expressed as "high", and a wire with a small distance is expressed as "low".

[Liquid ejection head]
As shown in FIG. 1, the liquid ejection head 11 includes a support member 12 and a plurality of element substrates 13 that eject ink (an example of liquid). The element substrate 13 is electrically connected to an FPC 14 (flexible printed circuits) with a metal wire (not shown) made of gold or the like. The electrical connection portion including the metal wire is insulated and coated with a sealing resin 15 or the like. Further, the FPC 14 is connected to a PWB 16 (printed wiring board) for electrical signal control by a wire 17 made of metal such as aluminum. The electrical connection portion including this wire 17 is also insulated and coated with a sealing resin in a later manufacturing process, similar to the connection portion between the element substrate 13 and the FPC 14.

As shown in FIG. 2(a), the FPC 14 and the PWB 16 are connected by a plurality of wires 17. In this embodiment, the FPC 14 and the PWB 16 are electrically connected using a wire 17 made of aluminum and having a diameter of 50 [μm]. The plurality of wires 17 connecting the FPC 14 and the PWB 16 include long wires 21 and short wires 22, and the long wires 21 and the short wires 22 are arranged alternately when viewed from above. As shown in FIG. 2(b), the vertical positional relationship in the BB' cross section is such that the long wire 21 passes at a higher position than the short wire 22. The positional relationship of the wires in this embodiment was set to X=0.11 [mm] and Z=0.16 [mm] in FIG. 2(b).

[Poor bonding]
One end of the wire 17 is connected to the FPC 14. Typically, the wire 17 is connected to a lead part (not shown) in which a metal part is exposed in the FPC 14. However, one end of the wire 17 may be slightly detached from the lead portion of the FPC 14 due to a manufacturing defect or an external force after manufacturing. This situation is shown as a defective portion 31 in the perspective view of FIG. 3(a). In the defective part 31, a dotted line 31a is a virtual line indicating the wire position during normal bonding, and a solid line 31b is a defective wire in a state where positional deviation has occurred. FIG. 3(b) is a plan view of the wire 17 viewed from directly above. When detecting a defective wire by visual inspection, the inspection is performed from directly above using a stereoscopic microscope or the like as shown in FIG. 3(b). In the example of FIG. 3, since the amount of lifting of the wire due to one side of the wire coming off is small, it is difficult to detect defects by visual inspection, as shown in FIG. 3(b).

FIGS. 4A and 4B show a case where the amount of deviation of the position of the defective wire in the defective portion 32 (solid line 32a) from the wire position during normal bonding (dotted line 32b) is relatively large. In this example, as the tip of the defective wire stands up vertically, the length of the wire when viewed from directly above changes, as shown in FIG. 4(b), and becomes shorter than during normal bonding. As a result, it is easier to distinguish by visual inspection using a stereomicroscope or the like than in the example shown in FIG. However, in both cases of FIGS. 3 and 4, the narrower the pitch between the wires, the more difficult it becomes to visually distinguish between them, increasing the possibility of overlooking poor connections. Therefore, there is a need for a method that can detect connection failures more accurately than conventional methods.

[Inspection device configuration]
FIG. 5 shows the inspection device 100 of this embodiment. The inspection apparatus 100 includes a single-axis robot 41, a stage 42 placed on the single-axis robot and on which an object to be measured is set, a ring-shaped LED illumination 43, a camera 44 used for imaging the bonding part, and a wire 17 connected to an air It has a blow nozzle 45a (first blow nozzle) and a blow nozzle 45b (second blow nozzle) for applying. It also includes a control device 200 that processes the captured image and determines whether the connection is good or bad. Note that the control device 200 may be considered to be included in the inspection device 100, or it may be considered that the inspection device 100 and the control device 200 cooperate to realize the inspection method.

Note that, in this embodiment, the blow nozzle 45a and the blow nozzle 45b are arranged in line-symmetrical positions in the horizontal direction with respect to the object to be inspected, but the positional relationship is not limited to this. The positional relationship of the blow nozzles can be changed as appropriate depending on the wire loop shape to be inspected, bonding position, etc. Further, the number of blow nozzles is not limited to two, and may be one or three or more.

In this embodiment, the inspection apparatus is configured to have a ring-shaped LED illumination 43, but the present invention is not limited to this, and any illumination that causes a sufficient brightness difference between the wire portion and the surrounding area may be used. For example, a plurality of lighting devices such as bar lighting may be used. Moreover, if the brightness difference is sufficient, it is not necessary to use LED lighting. Also, lighting other than LED may be used. Further, if the performance of the camera 44 is high or if the amount of light in the installation environment of the inspection device 100 is sufficient, the inspection device itself does not necessarily need to be equipped with illumination.

In this embodiment, the bonding portion between the FPC 14 and the PWB 16 of the liquid ejection head was inspected, but this inspection method can be used to identify defects not only in this location but also in any wire-connected area. be.

FIG. 6 is a diagram showing functional blocks of the inspection device 100. The control device 200 as a control means acquires information on each block of the inspection device 100 and controls the operation by transmitting a control signal to each block. As the control device 200, an information processing device such as a computer that is equipped with computing resources such as a processor, memory, and storage device can be used. The control device 200 includes blocks of a light source control section 210, an imaging control section 212, a ventilation control section 214, a transport control section 216, and an image processing section 218. Each of these blocks within the control device may be implemented as a program module or may be implemented by a dedicated processing circuit.

The light source control unit 210 controls the timing of turning on/off the LED lighting 43 and the amount of light. The LED lighting 43 may be considered as lighting means, or the light source control section 210 and the LED lighting 43 may be considered as lighting means. The imaging control unit 212 controls the imaging timing of the camera 44 and imaging parameters. The camera 44 may be considered as an imaging means, or the imaging control section 212 and the camera 44 may be considered as an imaging means. The air blowing control unit 214 controls the air blowing timing, wind speed, and air volume of the blow nozzle 45. Moreover, when a plurality of blow nozzles 45 are provided, which blow nozzle 45 blows air is controlled. The blow nozzle 45 may be considered as a blow means, or the blow control section 214 and the blow nozzle 45 may be considered as a blow means. The transport control unit 216 controls the transport timing and speed of the single-axis robot 41. The single-axis robot 41 may be considered as a transport means, or the transport control unit 216 and the single-axis robot 41 together may be considered as a transport means. The image processing unit 218 performs various image processing operations that will be explained in flowcharts below.

[Inspection flow]
The flow of the inspection process will be explained based on the flow of FIG.
(F1: Imaging preparation process)
By the operation of the single-axis robot 41, the area to be inspected is moved directly below the camera 44. The transport control unit 216 first controls the single-axis robot 41 to start moving the liquid ejection head 11 installed on the stage 42 (step S101). Then, when the bonding part to be inspected comes directly under the camera 44, the movement is stopped (step S102).

(F2: first imaging step)
In step S103, the control device 200 counts the time after the movement is stopped and waits until a preset imaging waiting time WT1 has elapsed. This is to suppress the influence of vibrations caused by movement on the captured image. When the imaging waiting time has elapsed, in step S104, the imaging control unit 212 controls the camera 44 to capture an image in the air blow OFF state (blow OFF image Img1). The captured image data is stored in the storage device of the control device 200.

(F3: second imaging step)
Next, in step S105, the air blow control unit 214 controls the blow nozzle 45a to turn on the blow. Then, in step S106, the imaging control unit 212 controls the camera 44 to capture and save the first blow-on image Img2. Then, in step S107, the blower control unit 214 controls the blow nozzle 45a to turn off the blow.

(F4: Third imaging step)
Next, in step S108, the air blowing control unit 214 controls the blow nozzle 45b to turn on the blowing state. Then, in step S109, the imaging control unit 212 controls the camera 44 to capture and save the second blow-on image Img3. Then, in step S110, the blower control unit 214 controls the blow nozzle 45b to turn off the blow.

(F5: Image processing and quality judgment process)
Next, the image processing unit 218 performs image processing in step S111, and determines whether the bonding is good or bad based on the result of the image processing in step S112. This process will be described later.

Next, the process advances to step S113, and the control device 200 determines whether the bonding portion currently being inspected is the final point. If the current position is the final point (Yes), the inspection ends. If there are other locations to be inspected (No), the process returns to F1 and continues.

[Image processing flow]
Next, image processing will be explained in accordance with the flow shown in FIG. In step S201, the image processing unit 218 performs gray conversion on the captured images (Img1 to Img3). Known gray scaling processing methods can be used for gray conversion. In this embodiment, 256 levels of gray scale processing are performed for pixel values from 0 to 255. Note that it is desirable that the difference in brightness between the wire and the surroundings becomes large in the image after gray conversion, and for this purpose, the RGB weighting coefficients can be changed as appropriate depending on the object to be measured.

Next, the image processing unit 218 extracts singular points on each image in step S202, and performs position correction between each image based on the extracted singular points in step S203. This is to cancel the influence of slight movement of the robot after it has stopped and vibration of the camera during imaging. Although the number of singular points extracted in this embodiment is 500, it is not limited to this and can be changed as appropriate depending on the device configuration, the shape of the object to be inspected, etc. Various known methods can be used to extract the singularity. For example, a corner or a corner in an image may be extracted as a singular point by edge extraction or contrast enhancement. The image processing unit 218 associates the singular point of the blow OFF image Img1 with the singular point of the first blow ON image Img2 (first matching), and also matches the singular point of the blow OFF image Img1 with the singular point of the second blow ON image Img3. Match the singular points (second matching).

In the position correction in step S203, the image processing unit 218 adjusts the first blow ON image Img2 so that the coordinates of the singular point of the first blow ON image Img2 match the coordinates of the singular point of the blow OFF image Img1. transform. For this purpose, the image processing unit 218 performs rotation processing, extension processing in the horizontal direction and vertical direction, contraction processing, etc. on the first blow ON image Img2. As a result, a first modified blow ON image Img2' is obtained. The image processing unit 218 similarly performs position correction processing on the second blow ON image Img3 based on comparison with the singular point of the blow OFF image Img1 to obtain a second modified blow ON image Img3'. Through this step, the coordinates of Img1 to Img3 can be aligned with respect to the blow-off image Img1, and the images can be compared with each other with high accuracy.

Next, in step S204, the image processing unit 218 extracts the difference between the blow OFF image and the blow ON image. Specifically, the image processing unit 218 calculates the difference between the first modified blow ON image Img2' and the blow OFF image Img1 as a first difference image Img4. Similarly, the image processing unit 218 calculates the difference between the second modified blow ON image Img3' and the blow OFF image Img1 as a second difference image Img5. The difference image is an image that represents the difference between when the blow is ON and when the blow is OFF, and the larger the pixel value of the difference image is, the larger the difference is. Therefore, when the poorly connected wire 17 is vibrating due to blowing, the pixel value of the difference image becomes large in the range where the wire 17 is vibrating.

Next, in step S205, the image processing unit 218 binarizes the difference image in order to delete portions that remain as differences due to slight brightness differences between the blow OFF image and the blow ON image, electrical noise of the camera, etc. do. A threshold is set during binarization, and pixels with a pixel value below the threshold have a pixel value of 0 in the binarized image, and pixels with a pixel value greater than the threshold have a pixel value of 0 in the binarized image. Set the value to 255. As a result, each pixel in the binarized image becomes either a white pixel (pixel value 255) or a black pixel (pixel value 0). The binarization threshold in this embodiment was set to 20 out of 256 gray scale levels. However, the threshold value is not limited to this, and can be changed as appropriate based on the slight brightness difference between the blow OFF/ON images that occurs in the imaging area and the electrical noise of the camera.

Next, in step S206, the image processing unit 218 performs contraction and expansion on the binarized difference image. Through this processing, as in S205, it is possible to cancel a slight difference in brightness between the blow ON/blow OFF images and the electrical noise of the camera. In addition, this processing also makes it possible to cancel the effects of vibrations on the entire imaging area due to blows and device vibrations. Note that the shrinking process for a binarized image is a process of converting a pixel of interest into a black pixel if at least one black pixel is included within a pixel range around the pixel of interest. On the other hand, the dilation process is a process in which the pixel of interest is made a white pixel if at least one white pixel is included in the peripheral pixel range around the pixel of interest.

In this embodiment, the contraction setting value was set to 2. That is, the shrinkage process was performed twice on the binarized difference image. However, the present invention is not limited to this, and the contraction setting value can be changed as appropriate according to the amount of vibration of the imaging area due to blowing. Note that since the dilation process is performed to restore the shrunk image to its original state, the dilation setting value was set to 2, the same as the contraction setting. Furthermore, in this embodiment, the range of surrounding pixels around the pixel of interest can be set as appropriate. For example, a 3 x 3 pixel range centered on the pixel of interest, a 5 x 5 pixel range centered on the pixel of interest, a cross-shaped range centered on the pixel of interest, a horizontally long or vertical range centered on the pixel of interest. etc. can be used as peripheral pixels.

Next, in step S207, the image processing unit 218 performs trimming to extract only the range where the wire exists within the imaging range. The method for specifying the range where the wire exists is arbitrary. For example, the range in the image may be specified in advance based on the angle of view of the camera and the position of the wire, or the range may be specified by the user. In this embodiment, the trimming process is performed after the collection/dilation process, but the timing is not limited to this, and may be performed in advance, such as after the difference extraction in S204.

Next, in step S208, the image processing unit 218 calculates the area of the area that is different between when the blow is ON and when the blow is OFF, based on the number of pixels that ultimately remain as a difference from the expanded image. Then, if the area of the different region is equal to or larger than a preset threshold, it is determined that there is a defective wire connection. In this embodiment, the threshold value is set to 1000, taking into account the size of pre-adhered foreign substances that can be blown away by blowing, and the size of glass cloth that protrudes from the PWB edge that cannot be blown away by blowing. However, the threshold value is not limited to this, and can be changed as appropriate based on the amplitude of the defective wire, the size of the foreign object, the size of the glass cloth, etc. Note that the image processing unit 218 of the present embodiment determines that there is a connection failure if the area of the difference region in either the first difference image Img4 or the second difference image Img5 is equal to or larger than the threshold value. This is because the way the wire 17 swings may change depending on the blow direction. However, the present invention is not limited to this, and it may be determined that there is a connection failure only when the area of the difference region is equal to or larger than a threshold value in both the first difference image Img4 and the second difference image Img5.

According to the inspection method described above, poor connection of wires can be easily detected. In particular, when inspecting a wire that is properly connected at one end and has a poor connection at the other end, the accuracy of detecting poor connections is improved compared to conventional technology that simply inspects images after blowing. . Furthermore, the air volume during inspection does not need to be so large as to blow away defective wires, but only needs to be large enough to cause the wires to sway, thereby suppressing adverse effects such as peeling off normal wires.

In the inspection method of the present invention, at least image processing is performed to compare an image when the blow is ON and an image when the blow is OFF. This makes it possible to perform a process of determining a defect by utilizing the fact that the amplitude of the defective wire during blowing is larger than the amplitude of the normal wire. Therefore, the processing order and contents of image processing do not necessarily have to follow the flow shown in FIG.

[Bonding wire inspection method]
A bonding wire inspection method for a liquid ejection head will be described in more detail with reference to the drawings. 9 to 11 are schematic perspective views showing a series of steps of a bonding wire inspection method. FIG. 12(a) is a schematic plan view of a captured image of a defective bonding wire when the blow is OFF, and FIG. 12(b) is a schematic plan view of the captured image when the blow is ON. FIG. 13(a) is a schematic diagram after extraction and binarization processing of the difference between the blow OFF and ON images, FIG. 13(b) is a schematic diagram after the contraction processing of FIG. 13(a), and FIG. 13(b) is a schematic diagram showing the state after the expansion process. FIG.

FIG. 9 shows how the inspection target portion 71 of the liquid ejection head 11 is moved directly under the camera 44 by the operation of the single-axis robot 41, and a blow-off image Img1 is captured. Here, an example will be shown in which five bonding portions are inspected one by one. In the flow of FIG. 7, this corresponds to S103 to S104.

Next, FIG. 10 shows how the blow nozzle 45a continues to blow air, captures a first blow ON image Img2, and turns off the blow after capturing the image. In the flow of FIG. 7, this corresponds to S105 to S107. The direction of air blowing from the blow nozzle 45a is set at an angle θ with respect to the surface of the liquid ejection head 11.

Next, FIG. 11 shows how to continue blowing air from the other blow nozzle 45b, capture a second blow ON image Img3, and turn off the blow after capturing the image. In the flow of FIG. 7, this corresponds to S108 to S110. The angle of the blow nozzle 45b with respect to the surface of the liquid ejection head 11 is also θ.

12(a) and 12(b) show captured images before performing various image processing. In this example, a bonding portion including a defective portion 81 is shown. FIG. 12(a) is a blow-off image Img1, and there is no change in the appearance of the defective wire. That is, it can be said that the defective wire in FIG. 12(a), like the defective part 31 in FIG. 3(a), is difficult to determine by visual inspection whether there is a connection defect.

FIG. 12(b) is a first blow ON image Img2, which shows how the defective wire in the defective portion 81 oscillates from side to side due to the blow. In this embodiment, since the defective wire vibrates at a very fast cycle, one end of the defective connection side of the wire appears to be widening in the image, as shown by the dotted line in the figure.

In this embodiment, as shown in FIG. 12(b), the defective wire oscillates from side to side starting from the wire position when the blow is OFF, but depending on the strength of the blow wind speed, etc. It may also oscillate left and right starting from different positions.

FIG. 13A is an image after extracting the difference between the blow OFF image Img1 and the first blow ON image Img2 and performing binarization processing (corresponding to S205 in FIG. 8). As shown in FIG. 13(a), the portion where the wire vibrates remains white (wire vibrating portion 91 in the figure). White dots are scattered in a part of FIG. 13(a). As described above, this indicates a slight difference between the blow OFF image Img1 and the first blow ON image Img2, which is caused by the brightness difference and the electrical noise of the camera. Further, there is one black line near the left-right symmetry axis of the wire vibrating section 91. This is the location where the wire was present when the blow was OFF, and since the difference between the blow OFF and blow ON is zero, one wire remains. Although it depends on the state of the reflected light from the wire, the width of this line roughly corresponds to the wire diameter.

FIG. 13(b) is an image after performing the contraction process (the first half of S206 in FIG. 8). As shown in FIG. 13(b), by performing the contraction process a set number of times, the area around the wire vibrating part 91 is removed, and the white dots can also be removed accordingly. Thereafter, the image shown in FIG. 13(c) is obtained by performing the expansion process the same number of times as the number of contractions (the second half of S206 in FIG. 8). Thereby, a binarized image of only the wire vibrating section 91 can be obtained. Thereafter, bonding failure is determined by calculating the area of the white portion of this image and comparing it with a threshold value (corresponding to S208 in FIG. 8).

Furthermore, similar processing is performed on the second blow ON image Img3. In addition, as shown in FIG. 9, if there is another inspection target location in the same liquid ejection head, the next inspection target location is moved using the single-axis robot 41 so that it is located directly under the camera, and the above-mentioned procedure is performed. Repeat test method.

In this embodiment, as shown in FIG. 9, a plurality of connection points (bonding parts) between the FPC 14 and the PWB 16 are inspected one by one, but the size of the object to be inspected and the camera/lens specifications necessary for inspection ( If the imaging range, resolution, depth of field, etc.) permit, the entire area may be inspected at one time. In addition, in this embodiment, the liquid ejection heads were set one by one in the device for inspection, and the head to be inspected was reset each time. It is also possible to set the head and perform the inspection all at once without replacing the head. When processing multiple bonding sections at once, the shape and performance of the blow nozzle should be such that it can blow the wires of multiple bonding sections.

Further, in this embodiment, a series of image processing shown in FIG. 8 was performed, but the present invention is not limited to this. For example, if a sufficient luminance difference between the wire and the surroundings can be ensured, gray conversion (S201 in FIG. 7) may be omitted. Furthermore, if the influence of vibrations, brightness differences, camera noise, etc. is small, extraction and matching of feature points, position correction, contraction and expansion processing, trimming processing, etc. can be omitted. As an example of simplifying image processing, a difference is extracted between the captured blow OFF image and blow ON image (corresponding to S204 in FIG. 7), and then the area of the difference is measured (corresponding to S208 in FIG. 7). It is also possible to judge whether it is good or bad. That is, image preprocessing and noise removal processing are not essential.

When a plurality of locations to be inspected are lined up horizontally as in this embodiment, it is desirable to blow at an angle as shown in FIGS. 9 to 11. The blow nozzle angle θ is desirably set to an angle that allows efficient blowing of even the short wire 22 shown in FIG. 2(b). For this purpose, it is necessary to set the blow nozzle angle so that the long wire 21 does not block the short wire 22 in the blow straight direction.

In the wire positional relationship of this embodiment, the preferred range of the nozzle angle in which the short wire is not blocked by the long wire is approximately θ=26 [°] to 55 [°]. Furthermore, a more preferable ideal range of the nozzle angle is about 32[°] to 37[°]. This is because when the nozzle angle becomes smaller than the ideal range, the long wires 21 overlap each other in the straight direction of the blow, and the long wire 21 on the side closer to the blow nozzle blocks the blow to the wire 21 on the far side. The same thing happens with short wires 21. Furthermore, if the nozzle angle is larger than the ideal angle, the long wire 21 will block the blow to the short wire 22. Furthermore, when the nozzle angle becomes larger than the ideal range and the blowing direction approaches perpendicular to the surface of the liquid ejection head 11, a force acts to restrain the wire in the vertical direction, which prevents the wire from swinging in the horizontal direction. It turns out. In view of these, in this embodiment, the blow nozzle angle θ was set to 35 [°]. Note that the blow angle can be appropriately selected depending on the distance between adjacent wires, the loop shape, the inspection range, the positional relationship with the inspection target location, and the like. When selecting the blow angle, it is necessary to take into consideration that the wires do not overlap in the direction of air blowing from the blow nozzle and that the blow angle is not perpendicular to the substrate or the like.

Furthermore, the relationship between the direction of the blow nozzle and the wire is desirably arranged at an angle that facilitates vibration of the defective wire. Taking FIG. 2(a) as an example, it is preferable to apply the blow from the side of the wire, that is, from the direction parallel to the cross-sectional line B-B'. In this embodiment, the amplitude of the defective wire is sufficiently obtained by blowing at an angle within ±30 [°] when the direction parallel to the cross-sectional line BB' in FIG. be able to. In this embodiment, the angle is 0 [°]. That is, blowing was performed in a direction perpendicular to the direction in which the wire was stretched. Note that the angle is not limited to this, and can be appropriately selected depending on the loop shape of the wire, the bonding position, etc.

Further, the blowing wind speed near the wire in this embodiment was about 22 to 25 [m/s]. As a result, the wind pressure load applied to the wire of this embodiment was approximately 0.06 to 0.08 [mN]. This is the wind speed necessary for the wire of this embodiment to obtain the amplitude necessary for defect determination, and the necessary amplitude is calculated from the binarization threshold, expansion/contraction settings, etc. That is, the blowing wind speed can be selected as appropriate, based on the wire diameter, material, binarization threshold, contraction/expansion settings, etc., as long as it can obtain an amplitude that allows determination of whether the wire is defective.

Furthermore, the blow target position in this embodiment was set at the center of the inspection range. For this purpose, the center of the area where the plurality of wires 17 are arranged is placed on the extension of the line extending from the nozzle tip in the air blowing direction. Further, the distance from the nozzle tip to the inspection target was 90 [mm]. This is to spread the blow over the entire inspection range. The target position and distance are not limited to these, and should be selected appropriately as long as the blow can be applied almost uniformly within the inspection range, taking into account the shape of the blow nozzle used, spray angle, wind speed, distance to adjacent wires, loop shape, etc. It is possible.

In this embodiment, a single-axis robot was used to sequentially send a plurality of connection points into the imaging range of the camera. However, the conveyance means is not limited to a single-axis robot, but may also be a robot arm or the like.

In this embodiment, the number of blow nozzles is two, and after one blow ON image is captured, the other blow ON image is captured, but the number is not limited to this. The number of blow nozzles may be one, or three or more. When there are a plurality of blow nozzles, blow ON images are sequentially captured, so while there is one blow OFF image, there are usually a plurality of blow ON images. Note that when a plurality of blow nozzles turn on blowing one by one, there are as many blow-on images as the number of blow nozzles. Note that a plurality of blow nozzles may be turned on at the same time, and in that case, there will be a difference in the number of blow nozzles and the number of turned-on images. Regarding the number of blow nozzles and which blow nozzle to select during blow-on imaging, it is preferable to apply blow almost uniformly within the inspection range.

As described above, by detecting wire shaking at a blowing wind velocity that is high enough to shake the wire, it is possible to identify defects based on the amplitude difference between the normal part and the normal part. Furthermore, since defects can be determined with a wind speed lower than that of the conventional technology, it is possible to inspect bonding defects while suppressing the influence on non-defective parts. In addition, since pass/fail is determined based on the difference between the blow OFF image and the blow ON image, even if there are differences in the FPC pasting position or bonding position for each inspection location, the inspection can be performed without being affected by the difference in position.

This inspection method is effective even in cases where the wire is slightly disconnected and it is difficult to determine whether the wire is disconnected, or where the pitch between the wires is narrow and visibility is low, as shown in Figures 3(a) and 3(b). . Further, in a configuration in which a plurality of wires are bonded to one pad on an FPC or PWB, for example, if only one of the plurality of wires becomes disconnected, it is not possible to determine a connection failure by electrical inspection. In such a case, the inspection method of the present invention is particularly effective.

Note that, as a means to facilitate inspection and discrimination, it is preferable to make the wire and the background part different colors in order to increase the difference in brightness between the wire and the background. For this purpose, either the wire or the background may be colored, or the wire and the background may be originally different colors. When coloring is performed, the timing of coloring may be either before or after bonding.

When there is a difference in height between adjacent wires as in this embodiment, it is desirable to arrange the adjacent wires so that they do not overlap in the vertical direction so as to facilitate inspection and discrimination. Furthermore, since one end of a defective wire comes off from the bonding position, it is desirable to set the bonding position at a distance from the adjacent wire so that the removed wire does not come into contact with the adjacent wire.

(Modified example)
In the embodiment described above, the quality of the connection is determined based on the difference between the blow OFF image and the blow ON image. However, if a poor connection exists, vibrations of the defective wire will be reflected in the blow-on image. Therefore, if a wire that behaves differently from a normal wire is observed in the blow-on image, it can be determined that there is a connection failure.

In this modification, the image processing unit 218 detects a connection failure based on the amplitude difference between the defective wire and the normal wire in the blow-ON image with respect to air blowing. For example, it is conceivable to store an image pattern characteristic of defective wires in advance and perform pattern matching processing. Specifically, if a pattern like the wire vibrating portion 91 in FIG. 13(a) is detected after the blow ON image is binarized, it can be determined that there is a connection failure.

(Second embodiment)
In the following, only the points different from the first embodiment described above will be explained, and the same parts as the first embodiment will be omitted.

[Poor bonding]
Examples of bonding defects other than those shown in FIGS. 3 and 4 are shown in FIGS. 14(a) to 14(c). FIG. 14A shows a case where both ends of the wire have come off from the FPC lead part (not shown) and the PWB terminal part (not shown) after bonding (indicated by reference numeral 46 in the figure). In this case, the wire 17 that should originally exist does not exist. Further, FIG. 14(b) shows a case where one end of the wire has come off and is in contact with an adjacent wire (indicated by reference numeral 47 in the figure). Furthermore, FIG. 14(c) shows a case where the wire with one end removed stands up vertically (indicated by reference numeral 48 in the figure). The free end side of the wire 48 that has risen here is out of the depth of field of the camera.

In FIG. 14(a), since the wire 17 is not present, the camera cannot take an image. Furthermore, in the case of FIG. 14(b), the wire 47 with one end removed is supported by the adjacent wire, so that no amplitude occurs due to blowing, or the magnitude of the amplitude due to blowing is suppressed. In the case of FIG. 14C, at least a portion of the free end of the raised wire 48 cannot be imaged because it is at a height higher than the depth of field of the camera. Therefore, in any of the cases shown in FIGS. 14(a) to 14(c), it cannot be determined that the wire is defective because the amplitude of the wire does not occur or the amplitude cannot be imaged because the depth of field is greater than the depth of field when inspecting only by blowing. Further, as in the above embodiment, the narrower the pitch between the wires, the more difficult it is to visually distinguish between the wires, increasing the possibility that defects may be overlooked.

In other words, in the method of determining the wire connection state using only high-pressure air as in the first embodiment, if a disconnected wire comes into contact with an adjacent wire, or if both ends of the wire are disconnected and are not present at that location, , since there is no difference between the blow ON and OFF images, it cannot be determined that there is a connection failure. Furthermore, if the end of the wire that has come off stands vertically and is out of the depth of field of the camera, there is a concern that the camera will not be able to capture the shaking of the wire when the blow is turned on. In such a case, it may not appear as a difference and it may not be possible to determine that the connection is defective.

Therefore, in the present embodiment, in wire bonding that electrically connects electrodes on an integrated circuit to electrodes on a printed wiring board, a semiconductor package, etc., even when a disconnected wire does not vibrate or is difficult to vibrate due to a blow, , provides a bonding wire inspection method that detects with high accuracy.

[Image processing flow]
FIG. 15 shows the processing flow of this embodiment. In this flow, image processing that is common to the image processing described in Embodiment 1 using FIG. 8 can be performed using the same algorithm as in Embodiment 1.

(Processing using blow ON images and blow OFF images)
After starting the flow, the control device 200 first performs image processing using the blow ON image and the blow OFF image, similarly to the first embodiment. The control device first performs gray conversion on each of the captured blow OFF image Img1, first blow ON image Img2, and second blow ON image Img3 (F11). Note that it is desirable that the luminance difference between the wire and the surroundings becomes large in the image after gray conversion, and the RGB weighting coefficients can be changed as appropriate depending on the object to be measured.

Next, the control device 200 extracts a singular point on the image and performs position correction (F12). This is to cancel the influence of slight movement of the robot after it has stopped and vibration of the camera during imaging. Although the number of singular points extracted in this embodiment is 500, it is not limited to this, and can be changed as appropriate depending on the device configuration, the shape of the object to be inspected, etc.

Next, the control device 200 extracts a difference between the gray-converted blow OFF image and the blow ON image as an image calculation (F13). Next, the control device 200 binarizes the difference image (F1
4). At this time, in order to delete portions that remain as differences due to slight brightness differences between the OFF image and ON image, electrical noise of the camera, etc., a threshold is set during binarization. I try not to leave it in the image. Although the binarization threshold value in this embodiment is set to 20, it is not limited to this, and can be changed as appropriate based on the slight brightness difference between the blow OFF/ON images that occurs in the imaging area and the electrical noise of the camera.

Next, the control device 200 performs contraction and expansion processing (F15). This is to cancel the effect of vibration of the entire imaging area due to blowing or device vibration, in addition to the slight brightness difference between the ON/OFF images mentioned above and the electrical noise of the camera. Although the contraction setting value is set to 2 in this embodiment, it is not limited to this, and can be changed as appropriate according to the amount of vibration of the imaging area due to blowing. Note that since dilation is performed to restore a shrunken image to its original state, the dilation setting value was set to 2, the same as the contraction setting.

Next, the control device 200 performs trimming to extract only the range where the wire exists within the imaging range (F16). In this embodiment, the processing is performed after expansion, but the timing of the processing is not limited to this, and may be performed in advance, such as after the difference extraction (F13).

Next, the control device 200 calculates the area of the number of pixels that ultimately remained as a difference from the expanded image, and determines that the wire connection is defective if it is equal to or larger than the set threshold (F17). In this example, the threshold value was set to 1000, taking into account the size of pre-adhered foreign matter that would be blown away by blowing, and the size of glass cloth protruding from the PWB edge that would not be blown away by blowing, but the threshold value is not limited to this. It can be changed as appropriate depending on the amplitude of the noise, the size of the foreign object, the size of the glass cloth, etc. Note that all of the above steps F11 to F17 are not necessarily essential, and if it is possible to perform a difference comparison using the blow ON image and the blow OFF image, one of the processes may be omitted, or other processes may be performed. May be added.

(Counting the number of wires)
Further, in the second embodiment, image processing for counting the number of wires is performed in parallel with the blow difference area determination performed in F11 to F17 (F18 to F25). First, the control device 200 converts the captured blow-off image Img1 into gray (F18). At this time, in order to emphasize the lead portion of the FPC and the terminal portion of the PWB, it is desirable to perform gray conversion by giving weight to R among RGB.

Next, the control device 200 performs trimming to extract only the range where the wire exists within the imaging range (F19). In this embodiment, the process is performed after gray conversion, but the timing is not limited to this, and may be performed at any timing such as after setting the wire count area (F22) or before counting the number of wires.

Next, the control device 200 sets a range for extracting reference points on the FPC and PWB sides (F20). Next, reference points that serve as standards for setting wire count areas are extracted on each of the PWB side and the FPC side (F21). Next, the control device 200 sets a wire count area of a predetermined distance and a predetermined range from the extracted reference point (F22). The wire count area is a predetermined area for counting the number of wires.

Next, the control device 200 binarizes the image (F23). At this time, as described above, a threshold value is provided when performing binarization, and images below the threshold value are not left in the image after binarization. Although the binarization threshold value in this embodiment is set to 20, it is not limited to this, and can be changed as appropriate based on the electrical noise of the camera that occurs in the imaging area.

Next, the control device 200 performs contraction and expansion processing (F24). This is to cancel the influence of vibration of the entire imaging area due to device vibration in addition to the electrical noise of the camera. Although the contraction setting value is set to 2 in this embodiment, it is not limited to this, and can be changed as appropriate based on the electrical noise of the camera that occurs, the change in brightness of the wire due to device vibration, etc. Note that since the dilation process is performed to restore the shrunk image to its original state, the dilation setting value was set to 2, the same as the contraction setting.

Next, the control device 200 calculates the final remaining area (number of pixels) from each image after contraction and expansion, determines that it is a wire if it is equal to or greater than a set threshold, and counts how many areas exist that are equal to or greater than the threshold. (F25). In this embodiment, the set threshold value is 140, but it is not limited to this, and can be set as appropriate depending on the size of the wire count area, that is, the length of the wire that falls into the count area, the thickness of the wire, the brightness of the reflected light from the wire, etc. Can be changed.

[Bonding wire inspection method]
In the second embodiment, in addition to the quality determination based on blowing described in the first embodiment, the following quality determination based on wire counting is performed.

FIG. 16(a) shows the reference points of PWB and FPC. The reference points for PWB are the protrusions extending in the left and right directions at the left and right ends of the terminal section 22 as reference points 111, and the reference points for FPC are the protrusions extending in the left and right directions at the left and right ends of the leads 21 as reference points 112. did. This example shows the wire 47 shown in FIG. 14(b) with one end dislodged and in contact with an adjacent wire.

As shown in FIG. 16(b), the control device 200 sets the PWB reference point extraction range 113 and the FPC reference point extraction range 114 using the blow-off image (Img1) of the inspection object (step F20). Then, the control device 200 extracts the PWB reference point 111 and the FPC reference point 112 by pattern matching processing using known technology based on information such as the shape of the reference point registered in advance as a master image (step F21). . Note that the reference point extraction range 113 on the PWB side is set wide in consideration of variations in the imaging position of the reference point due to the PWB fixing method and the like. On the other hand, the reference point extraction range 114 on the FPC side is designed to prevent erroneous detection due to the protruding shape and position of the adhesive 115 for pasting the FPC to the PWB, reflected light from the adhesive, etc. Based on this, the reference point extraction range is set inside the FPC.

Next, the control device 200 sets a wire count area at a position offset by a predetermined distance from the PWB reference point 111 and the FPC reference point 112, as shown in FIG. 17 (step F22). Regarding the PWB side, the control device 200 sets a PWB side wire count area 117 with a height H1 starting from a position offset by X1 and Y1 from the PWB reference point 111. Similarly, on the FPC side, the control device 200 sets a wire count area 118 on the FPC side with a height H2 starting from a position offset by X2 and Y2 from the reference point 112 on the FPC side.

In this embodiment, the wire count area is set near the connection portion of the PWB and near the connection portion of the FPC. This is because wire disconnection may occur on the PWB side or on the FPC side, so it was counted on both sides. Note that when a detached wire contacts an adjacent wire, it is desirable to set the count range to a position close to the connection part, taking into consideration that the contact will occur at a certain distance from the connection part of the PWB or FPC. Furthermore, in the wire bonding area (where the area of the FPC lead part and PWB terminal part is large), there is a possibility that the wire will be re-bonded due to equipment trouble, etc., and in that case, the wire will be bonded to an arbitrary position in the bonding area. It is desirable to set the count area at a position that does not overlap the bonding area.

FIG. 18(a) is a schematic diagram of the wire count area set in FIG. 17 subjected to the binarization process, in which the wire portions are shown in white, including the detached wire (reference numeral 121) that came into contact with the adjacent wire. In FIG. 18(a), some white dots are scattered, but this is due to places where reflected light from illumination is strong, such as metal dust adhering to the PWB or FPC, or due to electrical noise. Note that the lower row of wires represents the wires existing in the wire count area 117 on the PWB side, and the upper row represents the wires existing in the wire count area 118 on the FPC side.

Next, FIG. 18(b) shows a state in which the shrinkage process has been performed. It can be seen that the shrinking process leaves only wires with a thin line width and erases the white dots. Next, FIG. 18(c) shows a state in which expansion processing has been performed after that. In FIG. 18(c), a binarized image of only the wires can be obtained.

At the location where the wire 47 with one end removed is in contact with an adjacent wire, the wires appear to overlap, as shown by reference numeral 122 in FIG. 18(c), and the area of the white portion is larger than the other wires. . By setting a threshold value for this white area and counting it as one wire when it exceeds the threshold value, the number of wires on the upper FPC side will be one less than the number that should be, so it can be determined that there is a bonding defect. can.

In addition, when wire disconnection occurs at both ends of the wire as shown in FIG. 14(a), the count number becomes smaller than the original number in both the upper and lower rows, and it can be determined that the bonding is defective. Furthermore, as shown in FIG. 14(c), even in the case where the wire rises more than the depth of field, the counted number is smaller than the expected number, so it can be determined that the bonding is defective.

From the above, the control device 200 determines that the product is good only when the predetermined number of wires are counted in both count areas on the PWB side and the FPC side, and determines that the bonding is defective when the count is less than the predetermined number in both count areas. (Step F25).

Then, the control device 200 determines that the product is good only if both the blow and the count are determined to be good, based on the result of the quality determination by blowing (step F17) and the result of quality determination by wire counting (step F25). In this case, it is judged as defective.

In this embodiment, as in the example of FIG. 9, if there are other inspection points in the same liquid ejection head, a single-axis robot or the like is used to position the next inspection point directly below the camera. and repeat the above inspection method. In this embodiment, as shown in FIG. 9, the connection points between the multiple FPCs and PWBs were inspected one by one. , depth of field, etc.), the entire area may be inspected at one time instead of being divided into multiple inspections. In addition, in this example, the liquid ejection heads were set in the device one by one for inspection, and the head to be inspected was reset each time. It is also possible to set the head and perform the inspection all at once without replacing the head.

Further, in this embodiment, a series of image processing shown in FIG. 15 was performed, but the invention is not limited to this, and if a sufficient brightness difference between the wire and the surroundings can be ensured, the gray conversion (F11) can be omitted. Other processing can be omitted depending on the situation, such as less influence from vibrations, brightness differences, camera noise, etc. In that case, the difference may be extracted from the captured blow OFF and ON images (F13), and the area of the difference may be measured (F17) to determine the quality. Also, in the image processing flow for wire counting, gray conversion (F18) may be omitted if there is no possibility of misdetection of the reference point due to the influence of FPC adhesive protrusion, part shape, reflected light from lighting, etc. Alternatively, the reference point extraction range setting (F20) may be omitted and reference points may be extracted from the entire area of the captured image (F21).

Since a plurality of locations to be inspected in this embodiment are lined up horizontally, it is desirable to blow at an angle as shown in FIG. It is desirable that the blow nozzle angle θ is set to an angle that efficiently blows the short wire 24 shown in FIG. It is necessary to In the wire positional relationship of this embodiment, the nozzle angle at which the short wire 24 is not blocked by the long wire 23 is approximately θ = 26 [°] to 55 [°], but in reality it is approximately 32 [°] to 37 [°]. °] is desirable. This is because when the nozzle blow angle becomes acute or obtuse, the distance between the long wire 23 and the adjacent long wire 23 in the straight direction of the blow becomes shorter, and a part of the blow is blocked by the wire. Furthermore, when the nozzle angle is obtuse, the direction of the blow approaches the vertical direction, and a force that suppresses the wire in the vertical direction acts, which prevents the wire from swinging in the horizontal direction. In view of these, in this embodiment, the blow nozzle angle θ was set to 35 [°]. Note that the angle is not limited to this, and can be appropriately selected based on the distance to the adjacent wire, the loop shape, the inspection range, the positional relationship with the inspection target location, etc.

Furthermore, the relationship between the direction of the blow nozzle and the wire is desirably arranged at an angle that facilitates vibration of the defective wire. Taking FIG. 2(a) as an example, it is better to blow from the side of the wire, that is, from the direction parallel to the cross-sectional line BB'. In this embodiment, the amplitude of the defective wire is sufficiently obtained by blowing at an angle of about ±30 [°] when the direction parallel to the cross-sectional line BB' in FIG. 2(a) is set to 0. be able to. In this embodiment, the angle is 0 [°]. Note that the angle is not limited to this, and can be appropriately selected depending on the loop shape of the wire, the bonding position, etc.

Further, the blowing wind speed near the wire of this embodiment was approximately 22 to 25 [m/s] (corresponding to the wind pressure load applied to the wire of this embodiment = approximately 0.06 to 0.08 [mN]). This is the wind speed necessary for the wire of this embodiment to obtain the amplitude necessary for defect determination, and the necessary amplitude is calculated from the binarization threshold, expansion/contraction settings, etc. It is not limited to this wind speed, but can be selected as appropriate based on the wire diameter, material, binarization threshold, contraction/expansion settings, etc., as long as it can obtain an amplitude that allows determination of whether the wire is defective.

Furthermore, the blow aiming position in this example was set at the center of the inspection range, and the distance from the nozzle tip to the inspection target was 90 [mm]. This is to spread the blow over the entire inspection range. The target position and distance are not limited to these, and should be selected appropriately as long as the blow can be applied almost uniformly within the inspection range, taking into account the shape of the blow nozzle used, spray angle, wind speed, distance to adjacent wires, loop shape, etc. It is possible.

In this embodiment, the number of blow nozzles is two, and after one blow ON image is captured, the other blow ON image is captured, but the number is not limited to two, and three or more may be used. In the case of multiple blow-on images, the blow-on images are sequentially captured, so there is one blow-off image, but there are multiple blow-on images. Note that when a plurality of blow nozzles turn on blowing one by one, there are as many blow-on images as the number of blow nozzles. Note that a plurality of blow nozzles may be turned on at the same time, and in that case, there will be a difference in the number of blow nozzles and the number of turned-on images.

The reference point for wire counting is not limited to the shape described in this embodiment, but may have any shape. Further, the extraction method is not limited to pattern matching; for example, a portion having a higher reflectance than the other portions may be provided, and reference points may be extracted from the area by binarization and contraction/expansion processing. In addition, the wire count area in this example was set at two locations, one near the PWB connection and the other near the FPC connection. You can also set it.

As described above, a poorly connected wire is determined based on the amplitude difference from the normal part at a low blowing wind speed that shakes the wire. Furthermore, by identifying a reference position from the captured image, counting the number of wires within the wire count area set from the reference position, and determining a connection failure based on both the above-mentioned blow discrimination and the count results, it is possible to avoid connections that do not fluctuate due to blows. A defective product can also be determined to be defective. In addition, since blow OFF and ON images are captured for each inspection location to determine pass/fail, even if there are differences in the FPC pasting position or bonding position for each inspection location, as with the ejection head shown in Figure 1, the position It is possible to inspect without being influenced by differences.

This inspection method is effective in cases where the wire is slightly disconnected and it is difficult to determine whether the wire is disconnected, or where the pitch between the wires is narrow and visibility is low, as shown in FIG. 3(b). Further, in a configuration in which multiple wires are bonded to one pad on an FPC or PWB, for example, if only one of the multiple wires is disconnected, it is impossible to determine NG by electrical inspection. Such a configuration is a particularly effective inspection means.

Note that, as a means to facilitate inspection and discrimination, the wire and its surroundings may be colored in order to increase the difference in brightness between the wire and the background. Note that coloring may be done either before or after bonding.

If there is a height difference with the adjacent wire as in this example, the wire should be placed so that it does not overlap vertically with the adjacent wire, and the distance between the wire and the adjacent wire should be maintained to make it easier to distinguish during inspection and to make it easier to count when counting. It is desirable to set the bonding position by

According to this embodiment, it is possible to accurately determine a connection failure even in a state where the wire is blown and does not vibrate, such as when the wire is in contact with an adjacent wire or when both ends of the wire have come off and are no longer in place. Furthermore, even a wire that rises above the depth of field of the camera and becomes disconnected can be determined as a connection failure.

14: FPC14, 16: PWB, 17: Wire, 44: Camera, 45: Blow nozzle, 100: Inspection device, 200: Control device

Claims (19)

A wire bonding inspection device that connects the first member and the second member by connecting one end of the wire to the first member and connecting the other end of the wire to the second member,
blowing means for blowing air to the wire bonding;
an imaging means for imaging the wire bonding;
control means;
Equipped with
The image capturing means captures a blow ON image in a state where the air is being blown by the blowing unit and a blow OFF image in a state where the air is not being blown by the blowing unit,
The inspection device is characterized in that the control means inspects for poor connection of the wire by comparing the blow ON image and the blow OFF image. 2. The control means determines that there is a connection failure in the wire if the area of a region different between the blow ON image and the blow OFF image is equal to or larger than a threshold value. Inspection equipment as described. The control means acquires a difference image between the blow ON image and the blow OFF image, and determines that there is a connection failure in the wire if the number of pixels detected as a difference in the difference image is equal to or greater than a threshold value. The inspection device according to claim 1, characterized in that: 3. The inspection apparatus according to claim 2, wherein the control means compares the blow-on image and the blow-off image after performing positional correction based on feature points in the images. The blowing means includes a first blow nozzle and a second blow nozzle,
The first blow nozzle and the second blow nozzle blow the air to the wire bonding from different directions, respectively.
The inspection device according to any one of claims 1 to 4, characterized in that: The image capturing means captures a first blow ON image when the air is being blown from the first blow nozzle to the wire bonding, and the image capturing means captures a first blow ON image when the air is being blown from the first blow nozzle to the wire bonding. While the air is being blown, a second blow ON image is captured,
6. The control means compares the blow OFF image and the first blow ON image, and compares the blow OFF image and the second blow ON image. Inspection equipment as described. 6. The image capturing means captures a blow ON image when the air is being blown to the wire bonding from the first blow nozzle and the second blow nozzle. Inspection equipment. The first member and the second member are connected at a plurality of connection points, and the wire bonding is provided for each of the plurality of connection points,
The inspection device according to any one of claims 1 to 4, further comprising a conveyance unit that sequentially conveys the plurality of connection points to an imaging range by the image pickup unit. The inspection apparatus according to any one of claims 1 to 4, further comprising illumination means for illuminating the wire bonding. The control means counts the number of the wires in the blow-off image, and if the number of the wires is less than a predetermined number, determines that there is a connection failure in the wire. 4. The inspection device according to any one of 4. 11. The inspection apparatus according to claim 10, wherein the control means performs the counting by setting a predetermined area for counting the number of wires in the blow-off image. The inspection apparatus according to claim 11, wherein the control means sets a reference point in the blow-off image, and sets the predetermined area based on the reference point. 13. The inspection apparatus according to claim 12, wherein the control means sets the reference point using a master image registered in advance and the blow-off image. 12. The inspection method according to claim 11, wherein the control means sets a plurality of the predetermined areas. 15. The inspection device according to claim 14, wherein the plurality of predetermined regions include a region including one end of the wire and a region including the other end of the wire. A wire bonding inspection device that connects the first member and the second member by connecting one end of the wire to the first member and connecting the other end of the wire to the second member,
blowing means for blowing air to the wire bonding;
an imaging means for imaging the wire bonding;
control means;
Equipped with
The blowing means blows the air at a wind speed that causes the wire to vibrate when there is a poor connection between the wire and at least one of the first member and the second member,
The image capturing means captures an image in a state where the air is being blown,
The control means inspects whether or not there is a connection failure of the wire in the image based on an amplitude difference between the wire with the connection failure and the normally connected wire with respect to the air blowing. Inspection equipment for 17. The inspection device according to claim 16, wherein the blowing means blows the air at a speed that does not tear off the connection of the wire to the first member or the second member. A wire bonding inspection method that connects the first member and the second member by connecting one end of the wire to a first member and the other end of the wire to a second member, the method comprising:
an imaging means imaging the wire bonding in a state where air is being blown by the blowing means to create a blow-on image;
the imaging means imaging the wire bonding in a state where the air is not being blown by the blowing means to create a blow-off image;
a step in which the control means inspects for poor connection of the wire by comparing the blow ON image and the blow OFF image;
An inspection method having A wire bonding inspection method that connects the first member and the second member by connecting one end of the wire to a first member and the other end of the wire to a second member, the method comprising:
a step in which the imaging means captures an image in a state where air is being blown by the blowing means;
a step in which the control means inspects the presence or absence of a connection failure of the wire in the image based on an amplitude difference in relation to the air blowing between the wire with the connection failure and the normally connected wire;
has
The blowing means blows the air at such a wind speed that the wire vibrates when there is a poor connection between the wire and at least one of the first member and the second member. inspection method.

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