JP2021022637A - Inspection equipment of bonding wire, inspection method of bonding wire, and inspection program of bonding wire - Google Patents

Abstract

To provide an inspection equipment of bonding wire, an inspection method of bonding wire, and an inspection program of bonding wire.SOLUTION: Inspection equipment of bonding wire is equipped with imaging means for imaging multiple images of wires having different focuses, and acquiring the height information of a region subjected to wire bonding, profile line setting means for setting a profile line intersecting an inspection object wire, in an image where the wire is imaged, a height profile generating means for generating a height profile becoming the height information along the profile line in the height direction of the wire, a profile acceptable range setting means for setting an acceptable range indicating the minimum value or the maximum value of height in the height profile, and profile malfunction detection means for determining as malfunction when the height information in the height profile is deviated from the acceptable range.SELECTED DRAWING: Figure 1

Description

The present invention relates to a bonding wire inspection apparatus for inspecting bonded wires, a bonding wire inspection method, and a bonding wire inspection program.

In an electronic component to which wire bonding is performed, a wire appearance inspection as shown in Patent Document 1 and Patent Document 2 may be performed as an inspection of a bonding state. Specifically, the wires are accurately recognized one by one, and for example, the shape of the wires, the contact between the wires, and the like are inspected, and the height of the wires is inspected.

The wire recognition method described in Patent Document 1 recognizes the position of one connection portion (start point) of the wire and the position of the other connection portion (end point) of the wire by using the wire height image. The wire region between them is extracted as a wire. The wire recognition method described in Patent Document 2 forms a vertical cross-sectional focus distribution in which the wire focus distribution is expressed in the vertical cross section, and is in focus based on the vertical cross-sectional focus distribution. The locus of a single wire is tracked by tracking a portion having a high degree of focus. In this way, in Patent Document 1 and Patent Document 2, the height, bending, and the like of the extracted wire can be measured.

Japanese Unexamined Patent Publication No. 2016-157720 JP-A-2017-921187

The wire recognition methods described in Patent Document 1 and Patent Document 2 are effective when the number of wires is small. However, since the start point and the end point are set for each wire, the set amount becomes enormous when the number of wires is large. As a result, when the number of wires is as large as several hundred, it takes time to set and review the inspection conditions, and the productivity drops. Further, since the process of accurately recognizing the locus of the wire one by one is performed, the inspection process is complicated and the processing time is long. Further, when the wires intersect, the wires may not be identified only by the height image, it may be difficult to accurately identify the trajectories of the wires one by one, and the reliability of the inspection may be lowered. In addition, since the inspection result is output for each wire, it may take time and effort to verify and confirm the inspection result.

Therefore, in view of such circumstances, the present invention intends to provide a bonding wire inspection device, a bonding wire inspection method, and a bonding wire inspection program capable of improving the reliability of inspection and the processing speed. Is.

The bonding wire inspection device of the present invention is a bonding wire inspection device that inspects wires bonded to a connecting surface, and images images of wires having different focal points relatively close to and separated from the bonded wires. An imaging means that acquires height information of a region to which a wire is bonded while a plurality of images are taken, a profile line setting means that sets a profile line that intersects the wire to be inspected in the image in which the wire is captured, and the above. A height profile generating means for creating a height profile that provides height information along the profile line in the height direction of the wire, which is an approaching or separating direction, and a minimum or maximum height in the height profile. It is provided with a profile tolerance setting means for setting an allowable range indicating up to a value, and a profile abnormality detecting means for determining an abnormality when the height information in the height profile deviates from the allowable range.

According to the bonding wire inspection apparatus of the present invention, the imaging means can acquire a plurality of images having different focused pixel positions, and can acquire height information of the region where the wires are bonded. .. From this information, a height profile that serves as height information is created in the height direction of the wire. In this case, the inspection position is a position along the profile line specified by the user in the image in which the wire is captured. In the created height profile, an allowable range indicating the minimum or maximum value of the height of the inspection position is set, and if the height information in the height profile deviates from the allowable range, it is determined to be abnormal. Is.

In the above configuration, the profile line positioning means for positioning the profile line with respect to the work provided with the bonded wires may be provided. As a result, even if the position of the work on the screen shifts due to the rotation of the work or the like, the profile line is positioned following it, so that the inspection position can be kept constant.

In the above configuration, a data storage unit for setting a profile tolerance range is provided, and the profile tolerance setting means indicates an allowance indicating a minimum value to a maximum value based on the data stored in the profile tolerance setting data storage unit. It may generate a range. As a result, it is possible to simplify the time and effort of the user.

In the above configuration, the maximum value and the minimum value set in the profile tolerance setting means can be arbitrarily changed. As a result, the allowable range can be set to accurately reflect the actual bonding situation, and the reliability of the inspection can be improved.

In the above configuration, the intersection position between the profile line and the wire to be inspected may be an inspection position for inspecting the height of the wire. Further, a position other than the intersection position between the profile line and the wire to be inspected may be an inspection position for inspecting the height of the wire.

The bonding wire inspection method of the present invention is a bonding wire inspection method for inspecting wires bonded to a connection surface, in which a plurality of images of wires having different focal points are captured and the height of the region where the wires are bonded is obtained. Information is acquired, a profile line that intersects the wire to be inspected is set in the image in which the wire is captured, and a height profile that provides height information along the profile line in the wire height direction is created. Then, in the height profile, an allowable range indicating the minimum value or the maximum value of the height is set, and when the height information in the height profile deviates from the allowable range, it is determined as abnormal. ..

In the above configuration, the profile line may be positioned with respect to the work provided with the bonded wires.

In the above configuration, the set maximum and minimum values may be arbitrarily changed.

The bonding wire inspection program of the present invention is a bonding wire inspection program for inspecting a wire bonded to a connecting surface, and captures a plurality of images of wires having different focal points and a region where the wires are bonded. The step of acquiring the height information, the step of setting the profile line intersecting the wire to be inspected in the image in which the wire is captured, and the height information along the profile line in the height direction of the wire. A step of creating a height profile, a step of setting an allowable range indicating a minimum value or a maximum value of the height in the height profile, and a height information in the height profile deviating from the allowable range. It is provided with a step of determining an abnormality when the wire is present.

The bonding wire inspection apparatus, the bonding wire inspection method, and the bonding wire inspection program of the present invention have high inspection reliability and can improve the processing speed.

It is a block diagram which shows the inspection apparatus of the bonding wire of this invention. It is a figure which shows a part of the image of the workpiece provided with a wire and a connecting surface. (A) is a diagram showing a height profile, (b) is a diagram showing a waveform of a minimum value, (c) is a diagram showing a waveform of a maximum value, and (d) is a diagram showing an allowable range. (E) is a diagram showing a part of the height profile and the allowable range. It is a figure which shows the setting of another profile line in the image shown in FIG. It is a figure which shows a part of the image of another workpiece provided with a wire and a connecting surface. (A) is a diagram showing a height profile when the wires intersect, and (b) is a diagram showing a height profile when the wires intersect in other cases. It is a flowchart which shows the procedure of the inspection method of the bonding wire of this invention.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 7.

The bonding wire inspection device of the present invention determines whether or not the bonded wire is satisfactorily bonded when the wire tip is bonded to a pattern portion such as an electronic component or a terminal of a circuit board. It is to detect (inspect). If the height information is not normal in a certain part of the bonded wire and its surroundings, it is highly possible that the wire is not bonded well. Therefore, in the present embodiment, as the detection of the quality of the bonding wire, the quality of the bonding wire is detected by detecting the height information of the region where the wire is bonded. In the present embodiment, for the sake of simplicity, a case where seven bonding wires W1 to W7 are detected will be described as shown in FIG. 2, but in reality, a large number (for example, several hundreds or more) of bonding wires are used. It can be detected.

As shown in FIG. 1, the bonding wire inspection apparatus of the present invention includes an image pickup means 1, a memory 10 provided in a computer (not shown), an image creation means 11, a profile line setting means 2, and a profile line positioning means. 3. The height profile generating means 4, the profile allowable range setting means 5, the profile abnormality detecting means 6, and the profile allowable range setting data storage unit 13 are provided. In addition, a display means (monitor) (not shown) is connected to the computer.

The imaging means 1 is composed of a CCD camera or the like, and acquires an image of a work 20 including a bonding wire (hereinafter, simply referred to as a wire) and a connecting surface (bonding surface) which are imaging objects, and height information of a region where the wires are bonded. To do. The imaging means 1 can move in the z direction (up and down) so as to be relatively close to or separated from the work 20. That is, the imaging means 1 continuously changes the distance to the imaged object (scans the camera in the z direction) and acquires a plurality of images having different focal points in the vertical direction (the focused pixel positions are determined). Get different images for each). In this case, each image is in focus at only one position per image. That is, for each image, there is a pixel position having a high degree of focusing (a degree indicating how much the focus is in focus), and the pixel position is different for each image. The height information is relative distance information between the imaging means 1 and the work 20 at the time when the degree of focus is maximized for each pixel at the same time as imaging, and the imaging means 1 stores the height information.

The image creating means 11 creates a omnifocal image or a distance image in a shooting range based on a plurality of image data having different focal points acquired by the imaging means 1. In the present embodiment, the image creating means 11 creates a omnifocal image and a distance image based on the image data and the height information. A omnifocal image is an image that is in focus at all pixels. That is, in a plurality of images having different focal points acquired by the imaging means 1, the image creating means 11 evaluates the focus for each local region and reconstructs the omnifocal image reconstructed by the combination of the in-focus local images. create.

Further, the image creating means 11 creates a distance image (see FIGS. 2 and 4) based on the height information acquired by the imaging means 1. The distance image is an image in which height information is expressed by brightness according to the distance from the imaging means 1 (gray scale in the present embodiment), and height information of an object captured by the distance image can be obtained. .. For example, high-level objects (close to the imaging means 1) are represented in light colors (white in the case of grayscale), and low-level objects (close to the imaging means 1) are dark (grayscale). In the case of, it is expressed in black). Note that FIGS. 2 and 4 show distance images, and the actual image has black-and-white contrast.

The profile line setting means 2 sets and stores the profile line L as shown in FIG. The profile line L is a line in the direction crossing the wires W1 to W7 on all the images to be inspected in the image 12 (distance image in the present embodiment) in which the wires are captured. In this case, "crossing" means that the profile line L may intersect the wires W1 to W7 on all the images, and the angle of intersection between the wires W1 to W7 on each image and the profile line L does not matter. .. In the present embodiment, the entire area along the profile line L is the inspection position.

The profile line L allows the user to freely specify the length, direction, number, locus, and the like on the image (distance image in the present embodiment). That is, the user can freely specify the position of the wire to be inspected, and the profile line L can be freely drawn on the image. For example, when it is desired to inspect the height of all the wires W1 to W7 at a substantially intermediate position from one end side to the other end side, as shown in FIG. 2, the user is in the middle of the wires W1 to W7 on the image. Specify a straight line that the profile line L crosses at the position.

Further, when it is desired to inspect the heights of all the wires W1 to W7 near both ends, as shown in FIG. 4A, the user has a first profile on one end side of the wires W1 to W7 on the image. A straight line that the line L1 crosses is specified, and a straight line that the second profile line L2 crosses is further specified on the other end side of the wires W1 to W7 on the image. In this way, a plurality of profile lines L1, L2, ... May be provided. Further, as shown in FIG. 4 (b), when the location to be inspected differs depending on the wire, the direction of the profile line L may be changed or a curved line may be formed as shown in FIG. 4 (c). Good. In this way, the user can freely specify the position of the profile line L, and the profile line setting means 2 stores the position of the designated profile line L.

The profile line positioning means 3 positions the profile line L with respect to the work on the image displayed on the display means (screen). That is, when the work 20 has a positioning model (not shown) and the position of the model on the work 20 is stored in advance, the profile line positioning means 3 determines the relative positional relationship between the model and the profile line L. Remember. As a result, even if the position of the work 20 on the screen shifts due to rotation or the like, the profile line positioning means 3 corrects the position of the profile line so as to have the same positional relationship. That is, the profile line positioning means 3 shifts the profile line according to the position where the model is displaced. As a result, even if the position of the work on the screen shifts, the profile line is positioned following it, so that the inspection position can be kept constant.

The height profile generating means 4 generates a height profile as shown in FIG. The height profile is height information in the entire region along the profile line L in the height direction of the wire (the approaching or separating direction between the imaging means 1 and the work 20).

Since there is no wire intersection at the location shown in FIG. 2, height information appears in all the wires W1 to W7 in FIG. 3A, but as shown in FIG. 5, the wires intersect. If there is a location (the wire W1 overlaps the wire W2 and the wire W3 overlaps the wire W4), as shown in FIG. 6A, the lower wire (in this case, the wire W2 and For the wire W4), there is no height information in the height profile. Although not shown, when the wires partially overlap each other (for example, the wire W1 overlaps a part of the wire W2 and the wire W3 overlaps a part of the wire W4), FIG. As shown in (b), for the lower wire (in this case wire W2 and wire W4), the height information in the height profile overlaps with the upper wire (in this case wire W1 and wire W3) and has a small width. Appears. In this way, the height profile even expresses the crossing situation of the wires.

The profile allowable range setting means 5 has an allowable range (see FIG. 3D) indicating a minimum value (see FIG. 3B) to a maximum value (see FIG. 3C) of the height in the height profile. Is to set. In the work to be inspected, there is an allowable range as the distribution of height information on the profile line, and this is defined as the allowable range (hatched portion in FIG. 3D). That is, on the profile line, the waveform allowed as the minimum value of the height is set as shown in FIG. 3B, for example. Further, on the profile line, a waveform allowed as the maximum value of the height is set as shown in FIG. 3C, for example. Then, the region between the waveform of the maximum value and the waveform of the minimum value is the allowable range shown in FIG. 3D. The profile tolerance setting means 5 stores such an tolerance.

As a method of setting the allowable range, the user may specify a minimum value waveform and a maximum value waveform. In the present embodiment, the profile tolerance setting data storage unit 13 is provided, and the profile tolerance setting means 5 sets the minimum value to the maximum value based on the data stored in the profile tolerance setting data storage unit 13. The allowable range shown is automatically generated. For example, a plurality of non-defective workpieces are collected, and the range of variation between the maximum value and the minimum value is stored in the profile tolerance setting data storage unit 13 from the data, and the data corresponds to the data based on the data. The profile tolerance setting means 5 can automatically generate the tolerance so that the tolerance is within the tolerance. Further, the data storage unit 13 for setting the profile allowable range may store defective product data, and a range that does not correspond to the data may be set as the allowable range. Further, the design value is stored in the profile permissible range setting data storage unit 13, and the profile permissible range setting means 5 makes the waveform obtained by adding an arbitrary height based on the design value as the maximum value waveform, and is arbitrary. The minimum waveform can be set by subtracting the height of.

The profile abnormality detecting means 6 determines that there is a possibility of abnormality at the position when the height information in the height profile is out of the permissible range. For example, at a position on a certain profile line, the height profile is as shown by the solid line in FIG. 3 (e), and the allowable range set at the same position is the hatched portion in FIG. 3 (e). .. When the profile lines shown in FIG. 3 (e) correspond to (overlap) the allowable range, the height information h1 is between the minimum value and the maximum value (that is, the allowable range), so this position. It is assumed that there is no abnormality in. On the other hand, in the height information h2, since it is out of the range (allowable range) between the minimum value and the maximum value, it is assumed that there is some abnormality, and in the height information h3, the height is at a position where the height should be zero. Is not zero, and it can be said that it is out of the allowable range, so it is assumed that there is some abnormality. This may be the case, for example, when the wire is bent and the wire exists at a position where it should not exist.

The bonding wire inspection device of the present embodiment is a bonding wire inspection program for inspecting wires bonded to a connection surface, and captures a plurality of images of wires having different focal points and a region where the wires are bonded. The step of acquiring the height information of the wire, the step of setting the profile line intersecting the wire to be inspected in the image in which the wire is captured, and the height information along the profile line in the height direction of the wire. A step of creating a height profile to be obtained, a step of setting an allowable range indicating a minimum value a or a maximum value of the height in the height profile, and a step of setting height information in the height profile from the allowable range. It is provided with a step of determining an abnormality when it is out of alignment.

A bonding wire inspection method using the bonding wire inspection apparatus of the present invention will be described with reference to the flowchart of FIG.

The imaging means 1 acquires a plurality of real images having different focal points in the vertical direction so that the work 20 is within the photographing range (step S1). As a result, a plurality of image data having different focused pixel positions are stored in the memory 10, and height information of the region where the wires are bonded is stored in the memory 10.

The image creating means 11 creates a omnifocal image or a distance image in the shooting range based on a plurality of image data having different focal points and wire height information acquired by the imaging means 1 (step S2).

The user specifies the profile line L in the image created by the image creating means 11 (a distance image is used in this embodiment) (step S3). As a result, the profile line setting means 2 sets and stores the profile line L as shown in FIG. 2A, for example.

The height profile generation means 4 generates a height profile (step S4). The profile allowable range setting means 5 sets an allowable range indicating the minimum value to the maximum value of the height in the height profile (step S5). In the present embodiment, as a method of setting the permissible range, a plurality of non-defective data are stored in the profile permissible range setting data storage unit 13, and based on the data, the corresponding range becomes the permissible range. , The profile tolerance setting means 5 automatically generates the tolerance.

If the height information in the height profile is out of the permissible range, the profile abnormality detecting means 6 determines that there is a possibility of an abnormality at that location (step S6).

The user actually inspects the position identified as having the possibility of abnormality (step S7). In this case, when an abnormality is found at that position (step S8), the inspection device (inspection method) of the present embodiment accurately reflects the actual bonding situation, and when this inspection is completed (step S8). Step S9) ends. On the other hand, as a result of the actual inspection (step S7), if no abnormality is found at the position (step S8), the process returns to step S5 and the maximum value and the minimum value are changed. That is, the allowable range is reset. As a result, the allowable range can be set to accurately reflect the actual bonding situation, and the reliability of the inspection can be improved.

Even if the position on the screen of the work deviates from the initial position, such as during the inspection of the work or after the inspection of the work, the profile line positioning means 3 can be used with respect to the work on the screen. Position the profile line L. That is, the profile line positioning means 3 sets the position of the profile line L based on the relative positional relationship between the pre-stored work model and the profile line L so as to be similar to the stored positional relationship. Fix it. That is, since the profile line positioning means 3 shifts the profile line L according to the position where the model is displaced, the profile line L is positioned following the position, and the inspection position can be made constant. This positioning may be performed using an omnifocal image or a distance image.

In the bonding wire inspection device, the bonding wire inspection method, and the bonding wire inspection program of the present invention, a plurality of images having different focused pixel positions are acquired by the imaging means 1, and the wires are bonded. It is possible to acquire the height information of the area. From this information, a height profile that serves as height information is created in the height direction of the wire. In the created height profile, an allowable range indicating the minimum value to the maximum value of the height is set, and when the height information in the height profile deviates from the allowable range, it is determined as abnormal. As a result, the bonding wire inspection apparatus and the bonding wire inspection method of the present invention have high inspection reliability and can improve the processing speed.

In the above embodiment, all the regions on the profile line are set as inspection positions, but the inspection positions for inspecting the height of the wires at each of the positions where the wires W1 to W7 and the profile line L on the image intersect. May be. In this case, the inspection positions will be scattered. Further, a position other than the position where the wires W1 to W7 and the profile line L intersect on the image may be an inspection position for inspecting the height of the wire. In this case, the inspection positions will exist at predetermined intervals.

Further, in the embodiment, the allowable range is set between the minimum value waveform and the maximum value waveform, but the allowable range may be set only from the minimum value waveform. In this case, if the height information does not fall below the minimum value at that position, it is assumed that there is no abnormality. Further, the allowable range may be set only from the waveform of the maximum value. In this case, if the height information does not exceed the maximum value at that position, it is assumed that there is no abnormality.

Although the embodiment of the present invention has been described above, the present invention is not limited to the embodiment and can be modified in various ways. For example, the imaging means is not limited to the CCD camera, and various types such as a CMOS camera and the like can be used. Things can be adopted. As for the imaging direction, the imaging means was located above the imaged object and the imaging means moved up and down, but the imaging means was positioned horizontally with respect to the imaged object and the imaging means moved horizontally. You may. Further, the imaging means may be fixed so that the imaging object side approaches or separates from the imaging means.

The image creating means may be one that creates only a distance image, or may be one that creates only an omnifocal image. In the embodiment, the distance image is used as the image in which the wire is captured, but the omnifocal image may be used and the height data may be used. When a plurality of profile lines are provided, the number may be three or more. The profile line may be a line having no regularity or a line having a bend. The profile line positioning means and the data storage unit for setting the profile allowable range can be omitted. The number of wires to be inspected is arbitrary and may be at least one or many (for example, 100 or more).

1 Imaging means 2 Image creation means 3 Profile line positioning means 4 Height profile generation means 5 Profile tolerance setting means 6 Profile abnormality detecting means 12 Distance image 13 Profile tolerance setting data storage unit 20 Work W wire

Claims (10)

A bonding wire inspection device that inspects wires bonded to the connection surface.
An imaging means for capturing a plurality of images of wires having different focal points and acquiring height information of a region where the wires are bonded while being relatively close to and separated from the bonded wire.
A profile line setting means for setting a profile line that intersects the wire to be inspected in the image in which the wire is captured, and
A height profile generating means for creating a height profile that provides height information along the profile line in the height direction of the wire, which is the approaching or separating direction.
In the height profile, a profile allowable range setting means for setting an allowable range indicating a minimum value or a maximum value of height, and
A bonding wire inspection apparatus comprising: a profile abnormality detecting means for determining an abnormality when the height information in the height profile is out of the permissible range. The bonding wire inspection apparatus according to claim 1, further comprising a profile line positioning means for positioning a profile line with respect to a work provided with bonded wires. The profile tolerance setting data storage unit is provided, and the profile tolerance setting means generates an tolerance range indicating a minimum value to a maximum value based on the data stored in the profile tolerance setting data storage unit. The bonding wire inspection apparatus according to claim 1 or 2, wherein the bonding wire is inspected. The inspection of the bonding wire according to any one of claims 1 to 3, wherein the maximum value and the minimum value set in the profile tolerance setting means can be arbitrarily changed. apparatus. The bonding wire according to any one of claims 1 to 4, wherein the intersection position between the profile line and the wire to be inspected is an inspection position for inspecting the height of the wire. Inspection device. The invention according to any one of claims 1 to 4, wherein a position other than the intersection position between the profile line and the wire to be inspected is an inspection position for inspecting the height of the wire. Bonding wire inspection device. A bonding wire inspection method that inspects wires bonded to the connection surface.
Multiple images of wires with different focal points are taken, and height information of the area where the wires are bonded is acquired.
In the image in which the wire is captured, set a profile line that intersects the wire to be inspected.
In the height direction of the wire, a height profile that serves as height information along the profile line is created.
In the height profile, an allowable range indicating the minimum value or the maximum value of the height is set.
A method for inspecting a bonding wire, which comprises determining an abnormality when the height information in the height profile is out of the permissible range. The method for inspecting a bonding wire according to claim 7, wherein a profile line is positioned with respect to a work provided with the bonded wire. The bonding wire inspection method according to claim 7, wherein the set maximum value and minimum value can be arbitrarily changed. A bonding wire inspection program that inspects the wires bonded to the connection surface.
A step of capturing multiple images of wires with different focal points and acquiring height information of the area where the wires are bonded,
In the image in which the wire is captured, the step of setting the profile line that intersects the wire to be inspected, and
A step of creating a height profile that provides height information along the profile line in the height direction of the wire, and
In the height profile, a step of setting an allowable range indicating a minimum value or a maximum value of height, and
A bonding wire inspection program including a step of determining an abnormality when the height information in the height profile is out of the permissible range.

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