JPH06229729A - Bonding wire inspection system - Google Patents

Abstract

(57) [Abstract] [Object] The present invention relates to a bonding wire inspection apparatus for inspecting the shape of a bonding wire, and an object thereof is to perform more accurate shape inspection of a wire loop. [Structure] The coaxial epi-illumination unit 21 brightly illuminates the apex of the bonding wire 63. The image capturing unit 22 captures the light reflected directly above the wire 63. The oblique illumination unit 31 is
Light is emitted obliquely from above the wire 63 so that the apex of the wire 63 is brightly shined. The imaging unit 32 is the oblique illumination unit 31.
The reflected light at the apex of the wire 63 of the irradiation light is imaged.
The first image data storage unit 40 stores the image data corresponding to the output signals of the image capturing unit 22 and the image capturing unit 32. The wire loop apex three-dimensional position detection unit 43 detects the three-dimensional position of the apex of the wire 63 using the image data. The wire shape inspection unit 44 inspects the shape of the bonding wire 63 based on the three-dimensional position data of the apex of the wire 63.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bonding wire inspection device, and more particularly to a bonding wire inspection device for inspecting the shape of a bonding wire such as IC and LSI.

In recent years, ICs, LSIs, etc. have been widely used in large quantities, and the visual inspection of bonding wires of ICs, LSIs, etc. has been automated. In the bonding wire inspection device for automatically inspecting the bonding wire, the shape of the bonding wire is inspected, but it is necessary to be able to perform more accurate inspection.

[0003]

2. Description of the Related Art FIG. 22 is an explanatory view of a bonding wire shape. 22A is a plan view of the bonding wire viewed from directly above the IC, and FIG. 22B is a side view of the bonding wire viewed from the side surface of the IC. FIG. 22
As shown in FIG.
A ball 65 is formed so as to be connected to the pad 64 on the chip 61. On the other hand, the other end is connected to the lead 62 of the IC. The bonding wire 63 draws a curve, and the wire loop apex 6 is located near the end on the pad 64 side.
3a is formed.

FIG. 23 is an explanatory diagram of an optical system of a conventional bonding wire inspection apparatus, and FIG. 24 is an explanatory diagram of a conventional bonding wire inspection method. FIG. 24A shows a plan view of the bonding wire, and FIG. 24B shows a side view.

As shown in FIG. 23, in the conventional bonding wire detection device, the ring-shaped illumination 72 is used for illumination. In the image captured from directly above by the image capturing unit 71, the ring-shaped illumination 72 causes the light reflecting unit 66 in the apex region of the bonding wire shown in FIG. 24 to be the brightest.

In the inspection of the bonding wire in the conventional bonding wire inspection apparatus, the shape X of the bonding wire is inspected by detecting the position X and the length L of the light reflecting portion 66 in the apex region.

[0007]

FIG. 25 shows various states of the bonding wire. FIG. 25A is an example of a non-defective product.
The height H ₁ of the wire loop apex and the position X ₁ are within normal ranges. FIG. 25B shows an example in which the wire loop apex position X ₂ is within the normal range, but the height H ₂ is too low. FIG. 25C shows the wire loop vertex position X ₃
Is too close and the height H ₃ is too low.

Further, FIG. 25D shows an example in which the wire loop vertex position X ₄ is too far and the height H ₄ is too high. FIG. 25E shows an example in which the wire loop vertex position X ₅ is too far, the height H ₅ is too low, and the wire loop vertex region L ₅ is too long.

In the example shown in FIGS. 25 (C) to 25 (E), it is correctly determined as a defective product by detecting the positions X _{3 to} X ₅ and the lengths L _{3 to} L ₅ of the light reflecting portion 66. can do.

In the conventional bonding wire inspection apparatus shown in FIG. 23, however, the two-dimensional position of the bonding wire loop apex and the approximate three-dimensional shape near the wire loop apex can be detected, but the height of the wire loop apex is high. I can't inspect. Therefore, there is a problem in that the good product and the bad product may not be accurately discriminated.

For example, in the case of the defect shown in FIG. 25B, since the position X ₂ and the length L ₂ of the light reflecting portion 66 are within the range of good products, the height H _{2 of the} apex of the wire loop is too low. Cannot be detected.

The present invention has been made in view of the above points, and an object of the present invention is to provide a bonding wire inspection apparatus capable of detecting the height of a wire loop vertex and performing a more accurate shape inspection of the wire loop. .

[0013]

According to a first aspect of the present invention, there is provided a bonding wire inspection apparatus which stores image data of a bonding wire in an image data storage means and inspects the shape of the bonding wire using the image data. A first illuminating unit that irradiates light from directly above the bonding wire to brightly illuminate the loop apex of the bonding wire; a first imaging unit that images reflected light directly above the bonding wire; Second illuminating means for illuminating light obliquely from above to make the loop apex of the bonding wire bright, and light emitted from the second illuminating means reflected at the loop apex of the bonding wire Second image pickup at a position facing the illumination means
Image pickup means, and first image data storage means for storing image data corresponding to the output image signal of the first image pickup means and for storing image data corresponding to the output image signal of the second image pickup means. The two-dimensional position of the loop apex of the bonding wire is detected using the image data corresponding to the output image signal of the first image pickup means, and the image data and the second image data corresponding to the output image signal of the first image pickup means are detected. Is supplied from the wire loop apex three-dimensional position detecting means for detecting the three-dimensional position of the loop apex of the bonding wire using the image data corresponding to the output image signal of the imaging means And a first wire shape inspection means for inspecting the three-dimensional position and shape of the bonding wire based on the data of the wire loop vertex three-dimensional position. .

In the invention of claim 2, the irradiation direction of the bonding wire to the loop apex of the second illuminating means can be selected from a plurality of directions, and the second imaging means is the second illuminating means. The direction in which the image is picked up can be selected in accordance with the direction of the reflected light determined by the irradiation direction selected by the illumination unit.

According to a third aspect of the present invention, the optical axes of the second illuminating means and the second imaging means are in the same direction as the bonding wire to be inspected.

According to a fourth aspect of the present invention, the focal planes of the first and second image pickup means are made to coincide with the loop vertices of the reference bonding wire based on the three-dimensional position data of the loop vertices of the reference bonding wire. , The first and second
A stage is provided for adjusting the position of the image pickup means.

According to a fifth aspect of the present invention, in the bonding wire inspection apparatus for storing the image data of the bonding wire by the image data storage means and inspecting the shape of the bonding wire by using the image data, the bonding wire inspection apparatus is provided directly above the bonding wire. Third illuminating means for illuminating light to brightly illuminate the loop apex of the bonding wire; and fourth illuminating means for illuminating light from obliquely above the bonding wire to brightly illuminate the vicinity of the loop apex of the bonding wire. The depth of focus is sufficiently shallow compared to the height of the loop apex of the bonding wire, and the height of the focal plane is set by the stage, and the bonding wire is set at multiple heights within the imaging range including the reference height. A third image pickup device that picks up reflected light from above by a plurality of images and outputs a plurality of image signals at the plurality of heights. Means, a second image data storage means for storing a plurality of image data corresponding to a plurality of image signals at the plurality of heights supplied from the third imaging means, and the second image data storage means. A wire loop vertex two-dimensional position detecting means for detecting a two-dimensional approximate position of the loop vertex of the bonding wire using image data supplied from the above, and a plurality of image data at the plurality of heights and two of the loop vertices. Based on the wire loop apex position detection means for detecting the position of the loop apex of the bonding wire using the data of the dimensional approximate position, and the wire loop apex position data supplied from the wire loop apex position detection means, Second wire shape inspection means for inspecting the three-dimensional position and shape is provided.

According to a sixth aspect of the invention, the fourth illuminating means irradiates light in a direction traversing the bonding wire.

According to a seventh aspect of the present invention, the fourth illuminating means irradiates light in a direction substantially the same as the direction in which the bonding wire extends.

According to an eighth aspect of the invention, the wire loop vertex two-dimensional position detecting means detects the direction in which the bonding wire extends.

According to a ninth aspect of the present invention, the fourth illuminating means irradiates light from two directions facing each other with the bonding wire interposed therebetween.

According to a tenth aspect of the present invention, the third image capturing means captures each segmented range of the plurality of segmented image capturing ranges in the height direction as one screen while moving the focal plane, and each segmented range. An image signal of one screen is obtained for each.

According to the invention of claim 11, there is further provided an irradiation angle adjusting means for adjusting the irradiation angle of the fourth illuminating means based on the image data supplied from the second image data storing means. To do.

[0024]

According to the present invention, the image data obtained by picking up the image from directly above the bonding wire by the first image pickup means and the image data obtained from diagonally above the bonding wire by the second image pickup means. The three-dimensional position of the loop apex of the bonding wire can be detected from the image data. Therefore, the shape inspection of the bonding wire can be performed more accurately based on the obtained three-dimensional position data of the loop vertices.

According to the fifth aspect of the present invention, the fourth illuminating means causes the area around the loop vertex of the bonding wire to be brightly reflected, and the region including the wire loop vertex is correctly detected from the image data taken from directly above. The height of the wire loop apex is detected from the brightness of the image data at each height of the imaging range in the area. Therefore, the shape inspection of the bonding wire can be performed more accurately based on the obtained three-dimensional position data of the wire loop apex.

According to the tenth aspect of the invention, the height of the wire loop apex is determined by using the image data obtained by picking up the image of each divided range of the plurality of image pickup ranges in the height direction as one screen. Therefore, the time required for the inspection can be shortened.

In the eleventh aspect of the present invention, the irradiation angle adjusting means can optimally adjust the irradiation angle of the fourth illuminating means based on the image data obtained by the image pickup by the third image pickup means. .

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 is a block diagram of the essential parts of a first embodiment of the present invention, and FIG. 2 is a block diagram of the entire first embodiment. Also,
FIG. 3 shows a layout of the illumination / imaging system of the first embodiment, and FIG.
Shows an explanatory view of the illumination / imaging system of the first embodiment. Figure 4
FIG. 4A shows a configuration diagram of the illumination / imaging system 11, and FIG.
Shows a configuration diagram of the illumination / imaging systems 12 to 15.

As shown in FIGS. 1 and 4, the illumination / imaging system 1
Reference numeral 1 denotes a coaxial illumination unit 21 which is a first illumination unit and a first illumination unit.
The image pickup unit 22 is an image pickup unit. The coaxial incident illumination unit 21 includes a coaxial illumination 23, a half mirror 26, and an objective lens 27. The image pickup unit 22 includes an objective lens 27, a half mirror 26, an imaging lens 25, and an area sensor 24.

The illumination / imaging system 11 is arranged right above the bonding wire 63 to be inspected, and the optical axis of the illumination / imaging system 11 is substantially perpendicular to the chip 61 to which the bonding wire 63 is connected.

The light emitted from the coaxial illumination 23 is reflected by the half mirror 26 and converged by the objective lens 27,
The bonding wire 63 to be inspected is irradiated. Of the reflected light from the bonding wire 63, the light reflected at the apex of the wire loop is reflected right above, and the objective lens 27 and the imaging lens 25 cause the area sensor 24 to move.
The image is formed on the image plane of.

On the other hand, the light reflected at other than the apex of the wire loop is reflected in a direction other than directly above, and the area sense 2
No image is formed on the image plane of No. 4. Therefore, area sense 24
Only the light reflected at the apex of the wire loop of the bonding wire 63 is imaged on the imaging surface of. The area sensor 24 outputs a signal corresponding to the brightness of the image on the image plane.

FIG. 3A shows a layout view of the entire illumination / imaging system as seen from above, and FIG. 3B shows a side view of the illumination / imaging system. In the first embodiment, an illumination / imaging system 12, an illumination / imaging system 13, an illumination / imaging system 14, and an illumination / imaging system 15 are provided to form the second illumination means and the second imaging means. There is.

As shown in FIG. 3, the illumination / imaging system 12 and the illumination / imaging system 13 include a bonding wire 63 to be inspected.
They are arranged at positions facing each other with the optical axis interposed therebetween, and the angles formed by the optical axis and the horizontal are both θ. Similarly, the illumination / imaging system 14 and the illumination / imaging system 15 face each other with the bonding wire 63 to be inspected in between, and the angle between the optical axis and the horizontal is θ.
It is located in the position.

As shown in FIG. 4B, the illumination / imaging system 1
2 to 15 each include an oblique illumination unit 31 and an image pickup unit 32. The oblique illumination unit 31 includes a coaxial illumination 33, a half mirror 36, and an objective lens 37. The image pickup unit 32 includes an objective lens 37, a half mirror 36, an image forming lens 35, and an area sensor 34.

The oblique illumination unit 31 of the illumination / imaging systems 12 to 15
Among the image pickup units 32, a pair of the oblique illumination unit 31 and the image pickup unit 32 which face each other with the bonding wire 63 interposed therebetween are selected. The selected oblique illumination unit 31 and the selected imaging unit 32 are referred to as a second illumination unit and a second imaging unit, respectively. The selection of the oblique illumination unit 31 and the imaging unit 32 is performed so that optimal imaging can be performed according to the shape, position, etc. of the bonding wire 63 to be inspected.

In FIG. 1, as the second lighting means, lighting /
The case where the oblique illumination unit 31 of the imaging system 12 is selected and the imaging unit 32 of the illumination / imaging system 13 is selected as the second imaging unit is shown.

From the oblique illumination section 31 of the illumination / imaging system 12,
The bonding wire 63 is irradiated with light at an angle θ with the horizontal. Of this irradiation light, the light reflected at the apex of the wire loop is reflected at an angle θ with the horizontal, and the illumination / imaging system 1
It is focused by the image forming lens 37 of No. 3 and is imaged on the image pickup surface of the area sensor 34.

On the other hand, the light reflected at other than the apex of the wire loop is not imaged on the image pickup surface of the area sensor 34 of the illumination / image pickup system 13 because the light is reflected at an angle other than θ. Therefore, only the light reflected by the wire loop vertex of the bonding wire 63 is imaged on the imaging surface of the area sensor 34 of the illumination / imaging system 13.

As shown in FIG. 3A, the illumination / imaging system 1
1 to 15 can adjust the three-dimensional position by the XYZ stages 51 to 55, respectively. At the time of imaging the bonding wire 63, the XYZ stage 51 is arranged so that the focal plane of the illumination / imaging system 11 coincides with the apex portion of the wire loop of the bonding wire 63 which is the reference of the inspection target.
The position of the illumination / imaging system 11 is adjusted with.

Similarly, one of the XYZ stages 52 to 55 is arranged so that the intersection of the optical axes of the second illuminating means and the second imaging means coincides with the apex portion of the wire loop of the bonding wire 63 serving as a reference. Then, the position of any one of the illumination / imaging systems 12 to 15 selected as the second illumination means and the second imaging means is adjusted.

In FIG. 2, the illumination / imaging system 10
Includes illumination / imaging systems 11-15, and stage system 49 includes XYZ stages 51-55. As shown in FIG.
The stage system 49 uses the reference wire loop vertex position data 4
7 is moved by the control unit 46. Also,
The IC 60 to be inspected having the bonding wire is controlled by the frame feeder 48 under the control of the controller 46.
The sheet is conveyed to a predetermined position directly below the image pickup unit 22.

Next, the bonding wire 63 to be inspected
A method for detecting the three-dimensional position of the wire loop vertex will be described. FIG. 5 is an explanatory diagram of the image forming position on the reference wire, and FIG. 6 is an explanatory diagram of the image forming position on the wire displaced from the reference position. Further, FIG. 7 shows an explanatory diagram of a method for calculating the height of the wire loop apex.

FIG. 5A shows the apex P _A of the wire at the reference position and the image pickup surface N ₁ of the image pickup section 22 which is the first image pickup means.
5C shows the relationship between the upper imaging position and the imaging position on the imaging surface N ₂ of the second imaging means, FIG. 5B shows the imaging position on the imaging surface N ₁ , and FIG. ) Indicates an image forming position on the imaging surface N ₂ . Note that the image pickup magnifications on the image pickup surface N ₁ and the image pickup surface N ₂ are the same.

The light emitted by the coaxial epi-illuminator 21 is reflected right above the apex of the wire loop, and the image pickup surface N ₁
Imaged above. Further, the light emitted by the second illuminating means is reflected by the wire loop apex portion at an angle θ with the horizontal, and is imaged on the image pickup surface N ₂ of the second image pickup means.

As shown in FIG. 5, when the position of the wire loop apex P _A of the reference wire is (x ₀ , y ₀ , z ₀ ), the imaging position on the imaging surface N ₁ is (x ₀ , y ₀ ), while the imaging position on the imaging surface N ₂ is (u ₀ , v ₀ ).

[0047] FIG. 6 (A) is an imaging position on the imaging surface N ₁ of the test wire vertex P _D and the imaging unit 22 which is offset from the reference position, forming on the imaging surface N ₂ of the second imaging means 6B shows the relationship with the image position, and FIG. 6B shows the image forming position on the imaging surface N ₁ .
FIG. 6C shows an image forming position on the imaging surface N ₂ .

The light emitted by the coaxial epi-illuminator 21 is reflected right above the apex of the wire loop, and the image pickup surface N ₁
Imaged above. Further, the light emitted by the second illuminating means is reflected by the wire loop apex portion at an angle θ with the horizontal, and is imaged on the image pickup surface N ₂ of the second image pickup means.

As shown in FIG. 6, the wire of the inspection wire is
Apex P_DPosition of (x₁, Y₁, Z₁)
Image plane N₁The upper imaging position is (x₁, Y₁) Tona
2D position of the inspection wire (x₁, Y₁) Can be detected
It On the other hand, the imaging surface N₂The upper imaging position is (u₁, V₁)When
To do. Note that the wire loop vertices of the reference wire are shown in FIG.
P _AAnd its imaging position (x₀, Y₀), (U₀, V₀)
Shown together.

The difference between the inspection wire height z ₁ and the reference wire height z ₀ is determined as follows. The difference between the inspection wire height z ₁ and the reference wire height z ₀ z ₁ −z ₀
Is as follows according to FIG.

Z ₁ −z ₀ = P _C P _D = P _B P _D −P _B P _{C Further} , P _B P _D and P _B P _C can be respectively expressed as follows.

P _B P _D = (u ₁ −u ₀ ) / cos θ P _B P _C = (x ₁ −x ₀ ) tan θ Therefore, the reference wire height z _{0 of the} inspection wire height z ₁
The deviation amount z ₁ −z ₀ is calculated by the following formula.

Z ₁ −z ₀ = (u ₁ −u ₀ ) / cos θ− (x ₁ −x ₀ ) tan θ Next, details of the operation of the first embodiment will be described with reference to FIGS. 1 to 3. . In the frame feeder 48, the IC 60 to be inspected having the bonding wire 63 is
The sheet is conveyed to a predetermined position just below 2. Illumination / Imaging system 11
The three-dimensional position is adjusted by the XYZ stage 51 so that the focal plane matches the reference wire loop vertex position of the bonding wire 63 to be inspected.

On the other hand, in order to obtain the best image according to the shape and position of the bonding wire to be inspected, the second
The oblique illumination unit 31 which is the illumination unit of the above and the image capturing unit 32 which is the second image capturing unit are selected. FIG. 1 shows a case where the oblique illumination unit 31 of the illumination / imaging system 12 is selected as the second illumination unit and the imaging unit 32 of the illumination / imaging system 13 is selected as the second imaging unit.

Hereinafter, description will be made along the case where the oblique illumination unit 31 of the illumination / imaging system 12 is selected as the second illumination means and the imaging unit 32 of the illumination / imaging system 13 is selected as the second imaging unit. To do.

XY is set so that the intersection of the optical axes of the oblique illumination unit 31 and the image pickup unit 32 coincides with the apex position of the reference wire loop.
In the Z stages 52 and 53, the oblique illumination unit 31 and the imaging unit 32
The three-dimensional position of is adjusted.

Further, the oblique illumination unit 31 and the image pickup unit 32 are arranged so that the surfaces formed by the optical axes of the oblique illumination unit 31 and the image pickup unit 32 are substantially parallel to the surface formed by the reference wire loop.
The position of is adjusted.

Further, as shown in FIG. 1, illumination by the oblique illumination section 31 is performed from the side of the bonding wire 63 that is connected to the lead 62 on the outside of the chip, and the side opposite to the oblique illumination section 31 is illuminated. The image is captured by the image capturing unit 32. This prevents the reflected light from the rising portion of the wire loop 63 from the tip 61 to the vicinity of the apex of the wire loop from being reflected in the upward direction, and the reflected light in the upward direction of the imaging unit 22 is prevented. The image is not adversely affected.

The angle θ between the optical axis of the oblique illumination unit 31 and the image pickup unit 32 and the horizontal is as follows:
Set the wire so that strong light is not reflected directly upward.

The reflected light at the apex of the bonding wire 63 to be inspected of the irradiation light from the coaxial incident illumination unit 21 forms an image on the image pickup surface of the area sensor 24. Area sensor 2
Reference numeral 4 outputs an image signal corresponding to the brightness of the formed image. As a result, the image capturing unit 22 captures an image from directly above the apex of the inspection wire 63.

On the other hand, the reflected light at the apex of the inspection wire 63, which is the light emitted by the oblique illumination unit 31, is reflected by the area sensor 34.
An image is formed on the imaging surface of. The area sensor 34 outputs an image signal corresponding to the brightness of the formed image. As a result, the image capturing unit 32 captures an image of the apex of the inspection wire from diagonally above.

The image data storage means 40 includes an image input section 4
1 and an image memory. The image signal obtained by the area sensor 24 of the image pickup unit 22 is converted into digital image data of 256 gradations by the image input unit 41 and then stored in the image memory 42 as image data.

Similarly, the image signal obtained by the area sensor 34 of the image pickup section 32 is converted into digital image data of 256 gradations by the image input section 41 and then stored in the image memory 42 as image data.

Image pickup by the image pickup section 22 and the image pickup section 32 is performed for each area of a predetermined size in the IC 60 to be inspected, and image data corresponding to each area is stored in the image memory 42.

The movement from one image pickup target area to the next image pickup target area is performed by moving the respective illumination / imaging systems 11 to 15 by the XYZ stages 51 to 55 of the illumination / imaging systems 11 to 15.

Next, the operation of the wire loop apex three-dimensional position detecting section, which is the wire loop apex three-dimensional position detecting means, will be described. FIG. 8 illustrates an image pickup surface N directly above the image pickup unit 22.
The explanatory view of the process which calculates | requires the imaging position in ₁ is shown. Further, FIG. 9 is an explanatory diagram of a process of obtaining the image forming position on the oblique imaging surface N ₂ of the imaging unit 32.

FIG. 8A shows an original image of the image data obtained from the image formed on the image pickup surface N ₁ of the image pickup section 22.
The dotted lines 67 _{A1 to} 67 _A3 indicate bonding wires, and 6
8 _{A1 to} 68 _A3 indicate the light reflection parts at the tops of the wire loops having the highest brightness. Also, the alternate long and short dash line in the y direction indicates the reference position x ₀ of the wire loop apex.

First, the original image of the image data is scanned in the y direction, and a signal of brightness on a line passing through the wire loop apex is obtained for each wire. FIG. 8B is the same as FIG.
The signal of the brightness on the line m ₁ of (A) is shown. Data of this brightness signal is binarized at a predetermined slice level SL ₁ to obtain a binary signal shown in FIG. 8 (C). The slice level SL ₁ is, for example, a half value of the maximum brightness MAX ₁ .

This binary signal and the scanning line m₁Width of
The light reflecting portion 68 shown in FIG. _A2Binary corresponding to
Image 69_A2Is obtained. Light reflection part 68 of other wire_A1，
68_A3Binary image 69 corresponding to_A1, 69_A3Similarly
can get.

This binary image 69 _Ai (in the example of FIG. 8, i =
1-3), the center position of the image forming position (x _i , on the imaging surface N ₁ corresponding to the wire loop apex of the wire 67 _Ai , x _i ,
y _i ) is obtained. This image formation position is equal to the two-dimensional position (x _i , y _i ) of the wire loop vertex to be obtained.

The image forming position on the oblique image pickup surface N ₂ of the image pickup section 32 is obtained in the same manner as the image forming position on the image pickup surface N ₁ directly above the image pickup section 22.

FIG. 9A shows an original image of image data obtained from an image formed on the image pickup surface N ₂ of the image pickup section 32 which is the second image pickup section. Dotted lines 67 _{B1 to} 67 _B3 indicate the same bonding wires as the bonding wires 67 _{A1 to} 67 _A3 of FIG. 8A, respectively, and 68 _{B1 to} 68 _B3 indicate the light reflecting portions at the top of the wire loop having the highest brightness. Show. Also, the alternate long and short dash line in the v direction indicates the reference position u ₀ of the wire loop apex. The light reflecting portions 68 _{A1 to} 68 in FIG.
_A3 corresponds to the light reflecting portions 68 _{B1 to} 68 _B3 in FIG. 9 (A).

The original image of the image data is scanned in the v direction,
The brightness signal on the line passing through the wire loop apex is obtained for each wire. FIG. 9B shows the brightness signal on the line m ₂ in FIG. 9A. In addition, line m
₂ passes through the same vertex as the wire loop vertex through which the line m ₁ in FIG. 8 (A) passes.

The data of this brightness signal is binarized at a predetermined slice level SL ₂ to obtain a binary signal shown in FIG. 9 (C). The slice level SL ₂ is, for example, a half value of the maximum brightness MAX ₂ .

This binary signal and the scanning line m₂Width of
, A binary image 69 shown in FIG. _B2Is obtained. other
Light reflection part 68 of the wire_B1, 68_B3Binary image corresponding to
69_B1, 69_B3Can be similarly obtained.

This binary image 69 _Bi (in the example of FIG. 9, i =
1-3), the center position of the image forming position (u _i , on the imaging surface N ₂ corresponding to the wire loop apex of the wire 67 _Bi is determined.
v _i ) is obtained.

The imaging position on the image pickup surface N ₁ obtained as described above, that is, the two-dimensional position (x _i , y _i ) of the wire loop vertex, and the image pickup surface N of the same wire loop vertex are obtained.
_{From the} image forming position (u _i , v _i ) on the position ₂ , the deviation amount between the height z ₀ of the apex of the reference wire loop and the height z _{i of the} apex of the inspection wire wire loop is obtained.

As described with reference to FIGS. 5 to 7, z _i −
z ₀ is calculated by the following formula.

Z _i −z ₀ = (u _i −u ₀ ) / cos θ− (x _i −x ₀ ) tan θ Note that the coordinates x and y are the same as the coordinates u and v are the same. For the inspection wire, z _i −z ₀ is
It is calculated by the following formula.

Z _i −z ₀ = (v _i −v ₀ ) / cos θ− (y _i −y ₀ ) tan θ Next, the wire shape inspection unit 44 that is the first wire shape inspection means will be described. The wire shape inspection unit 44 is supplied with the three-dimensional position data of the wire loop apex of the bonding wire to be inspected from the wire loop apex three-dimensional position detection unit 43.

The wire shape inspection unit 44 inspects the shape of the inspection wire from the three-dimensional position data of the wire loop apex of the inspection wire and the position data of the reference wire loop. That is, the quality of the shape is judged from the height of the wire loop, the position of the apex, the length of the apex, and the like. Also, from the three-dimensional position data of the wire loop apex of the inspection wire, the position data of the reference wire loop, and the position data of the pad 64, the lead 62, etc., the direction in which the inspection wire extends, the distance between adjacent wires, etc. Determines whether is within the standard range.

As described above, in the first embodiment, the image data obtained by picking up an image from directly above the inspection wire by the image pickup section 22 which is the first image pickup means, and the image data of the inspection wire obtained by the second image pickup means. It is possible to detect the three-dimensional position of the wire loop apex of the inspection wire from the image data obtained by imaging from diagonally above. Therefore, the shape inspection of the bonding wire can be performed more accurately based on the obtained three-dimensional position data of the wire loop apex.

FIG. 10 is a block diagram showing the essential parts of the second embodiment of the present invention, and FIG. 11 is a block diagram showing the entire structure of the second embodiment.
FIG. 12 shows a perspective view of the illumination / imaging system of the second embodiment.

As shown in FIGS. 10 and 12, the coaxial epi-illumination unit 121, which is the third illuminating means, includes the coaxial illumination 123,
It is composed of a half mirror 126 and an objective lens 127. In addition, the image capturing unit 122 that is the third image capturing unit includes an objective lens 127, a half mirror 126, and an imaging lens 12.
5 and the area sensor 124.

The image pickup section 122 is arranged right above the bonding wire 63 to be inspected, and the optical axes of the image pickup section 122 and the coaxial epi-illumination section 121 are substantially perpendicular to the chip 61 to which the bonding wire 63 is connected. There is.

The light emitted from the coaxial illumination 123 is reflected by the half mirror 126, converged by the objective lens 127, and irradiated onto the bonding wire 63 to be inspected with the light L _0.
Is irradiated as. Of the reflected light from the bonding wire 63, the light reflected at the apex of the wire loop is reflected right above, and the objective lens 127 and the imaging lens 12 are reflected.
5, the image is formed on the image forming surface of the area sense 124.

On the other hand, the light reflected at other than the apex of the wire loop is reflected in directions other than directly above, and the area sense 1
No image is formed on the image plane 24. Therefore, area sense 1
On the image forming plane of 24, only the light reflected by the wire loop apex of the bonding wire 63 among the irradiation light from the coaxial incident illumination unit 121 is imaged.

As shown in FIG. 12, in the second embodiment, oblique illumination units 131 to 134 are provided. 10 and 12
As shown in FIG.
Are arranged at opposite positions with the bonding wire 63 to be inspected therebetween, and the angles formed by the optical axis and the horizontal are β ₁ and β ₂ , respectively. Similarly, the oblique illumination unit 1
33 and the oblique illumination section 134 are opposed to each other with the bonding wire 63 to be inspected in between, and are arranged at a position where the angle between the optical axis and the horizontal is β.

Any one of the oblique illumination units 131 to 134 or any two oblique illumination units facing each other with the bonding wire 63 to be inspected interposed therebetween is selected, and the fourth
Lighting means. This oblique illumination unit is selected so that optimum imaging can be performed according to the shape, position, etc. of the bonding wire 63 to be inspected. In FIG. 10, the oblique illuminating section 131 and the oblique illuminating section 132 that face each other with the bonding wire 63 interposed therebetween are selected as the fourth illuminating means.

FIG. 13 shows an illustration of the illumination method of the second embodiment. 13A is a plan view seen from the upper surface of the bonding wire 63, and FIG. 13B is a line q in FIG. 13A.
FIG. 13C is an enlarged plan view in the vicinity of the line q.

In the second embodiment, as shown in FIGS. 10 and 13, the oblique illumination portions 131 and 132 are arranged so as to cross the bonding wire 63 and form an angle β with the horizontal, respectively.
Lights L ₁ and L ₂ are emitted by ₁ and β ₂ .

As shown in FIGS. 13 (B) and 13 (C), the irradiation light L ₁ by the oblique illumination units 131 and 132,
Of L ₂ , the light reflected by the regions 82 and 83 slightly outside the vertex of the wire loop is reflected right above,
The light is focused by the objective lens 127 and the image forming lens 125 of the image pickup unit 122, and an image is formed on the image pickup surface of the area sensor 124.

On the other hand, of the irradiation lights L ₁ and L ₂ emitted by the oblique illumination units 131 and 132, the lights reflected from regions other than the slightly outer regions 82 and 83 near the wire loop apex are directed in directions other than directly above. Since it is reflected, it does not form an image on the imaging surface of the area sensor 124 of the imaging unit 122.

Therefore, the wire loop apex reflecting portion 8 for reflecting the light L ₀ emitted by the coaxial epi-illuminator 121 in the directly upward direction.
1 and irradiation lights L ₁ and L from the oblique illumination units 131 and 132
_The areas 82 and 83 that reflect ₂ directly upward are the image pickup unit 1
Imaged brightly by 22. The areas 82 and 83
Is wider than the vertex reflecting portion 81.

The area sensor 124 is the coaxial epi-illumination unit 1.
21, the reflected light of the irradiation light L ₀ and the oblique illumination unit 131,
The irradiation lights L ₁ and L ₂ reflected by 132 output a signal corresponding to the brightness of the image formed on the image plane.

The coaxial epi-illumination unit 121 and the image pickup unit 12 are provided.
2, the three-dimensional position is adjusted by the XYZ stage 151. Further, the oblique illumination units 131 to 134 have their three-dimensional positions adjusted by their respective XYZ stages so as to irradiate light to the vicinity of the apex of the bonding wire 63 at an appropriate angle.

The depth of focus of the image pickup section 122 is sufficiently shallower than the height H of the wire loop of the bonding wire 63. Therefore, an image on the focal plane of the image capturing unit 122 is clearly and brightly imaged, and an image at a position out of the focal plane is blurred and imaged with reduced brightness.

In FIG. 11, the illumination / imaging system 11
0 includes the coaxial incident illumination unit 121, the image capturing unit 122, and the oblique illumination units 131 to 134. The stage system 149 includes the XYZ stage 151 and the XYZ stages of the oblique illumination units 131 to 134. As shown in FIG. 11, the stage system 149
Are moved by the control unit 146. Further, the IC 60 to be inspected having the bonding wire is connected to the control unit 14
Under the control of No. 6, the frame feeder 148 conveys the image to a predetermined position just below the image pickup unit 122.

Next, the operation of the second embodiment will be described in detail with reference to FIGS. Frame feeder 1
At 48, the I to be inspected having the bonding wire 63
The C60 is conveyed to a predetermined position directly below the imaging unit 122.

The image pickup section 122 picks up images at fixed height steps in the image pickup range set in a predetermined height range.
The imaging range is set to a predetermined range above and below the reference position with the height of the reference wire loop apex as the reference position.

The image pickup section 122, before the start of image pickup,
The height is adjusted by the stage 151 so that the focal plane coincides with the position of the lower limit (for example, the surface of the pad 64 of the IC 60) in the imaging range.

On the other hand, according to the shape and position of the bonding wire to be inspected, the fourth image is obtained so that the best image can be obtained.
The oblique illumination unit, which is the illumination means of, is selected. In FIG. 10, as the fourth lighting means, the oblique lighting units 131 and 132 are used.
Shows the case where is selected. Hereinafter, description will be given along with the case where the oblique illumination units 131 and 132 are selected as the fourth illumination means.

Irradiation light L from the oblique illumination units 131 and 132
₁ , L ₂ near the apex of the bonding wire 63,
The XYZ stages of the oblique illuminators 131 and 132 respectively irradiate the oblique illuminators substantially at right angles from above, and the oblique illuminators 131 and 132 allow the oblique illuminators 131 and 132 to be reflected right above.
The three-dimensional position of 132 is adjusted.

The depth of focus of the image pickup section 122 is set sufficiently shallower than the height of the wire loop of the bonding wire.
Therefore, the reflected light from the portion of the wire loop of the bonding wire 63 on the focal plane of the image capturing unit 122 is clearly imaged on the image capturing surface of the area sensor 124 with high brightness, and deviates from the focal plane. The reflected light at the open portion is blurred and imaged with low brightness.

When the apex portion of the bonding wire 63 is on the focal plane of the image pickup section 122, the coaxial incident illumination section 121 is provided.
The light reflected by the apex reflection portion 81 of the bonding wire 63 is sharply imaged on the image pickup surface of the area sensor 124 to be brightly imaged. On the other hand, the reflected light in the areas 82 and 83 slightly outside the apex portion of the wire loop of the inspection wire 63, which is the irradiation light from the oblique illumination units 131 and 132, forms a clear image on the imaging surface of the area sensor 124. It is brightly imaged.

The area sensor 124 outputs an image signal corresponding to the brightness of the image obtained by picking up the image as described above.

In the actual image pickup of the bonding wire 63, the image pickup section 122 is moved by the XYZ stage 151 upward in the image pickup range, and is picked up at fixed height steps. Thereby, a plurality of image signals at each height of the imaging range can be obtained.

The second image data storage means 140 comprises an image input section 141 and an image memory 142. The plurality of image signals at each height obtained by the area sensor 124 are converted by the image input unit 141 into digital image data of 256 gradations, and then stored in the image memory 142 as image data corresponding to each height. To be done.

The image pickup by the image pickup unit 122 is performed for each area of a predetermined size in the IC 60 to be inspected, and the image data corresponding to each area is stored in the image memory 142.
Remember.

The movement from one image pickup target region to the next image pickup target region is performed by the coaxial incident illumination unit 121 and the image pickup unit 12.
2. The oblique illumination units 131 and 132 are moved by respective XYZ stages.

Next, the operation of the wire loop vertex two-dimensional position detecting section 144, which is the wire loop vertex two-dimensional position detecting means, will be described. The wire loop vertex two-dimensional position detection unit 144 includes the vertex of the bonding wire 63 to be inspected by using the image data at the reference height of the wire loop vertex (reference height) supplied from the image memory 142. Find a two-dimensional area.

FIG. 14 is an explanatory view of the original image of the bonding wire at the standard height. FIG. 14A shows an original image of the bonding wire, and FIG. 14B shows the original image.
The signal of the brightness on the line r of (A) is shown.

In FIG. 14 (A), the vicinity of the wire loop apex in focus is clearly imaged, and the pad 64, the ball 65, and the like out of focus are blurred. As shown in FIG. 14, the wire loop apex S ₁ and the pad 64 are brightly imaged by the illumination of the coaxial incident illumination unit 121. The areas S ₂ and S ₃ near the apex of the wire loop are brightly imaged by the illumination of the oblique illumination unit 131.

As shown in FIG. 14B, a signal with high contrast is obtained near the wire loop apex on the line r. Further, the other portion of the bonding wire 63 is dark, and the pad 64 and the other portion have intermediate brightness.

FIG. 15 is an explanatory diagram of the wire loop vertex two-dimensional position detection processing. When the original image of FIG. 14A is scanned in the direction parallel to the line r that crosses the bonding wire 63 and binarized at the slice level SL ₃ shown in FIG. 14B, the black portion of FIG. 15A is obtained. As shown by, the binarized areas S ₂ and S ₃ can be detected.

Although there may be a plurality of bonding wires in one screen, the area S of each wire loop is determined by the inclination of the bonding wire 63 with respect to the scanning direction.
₂ , S ₃ can be identified.

As shown in FIG. 15 (A), the lines r ₁ and r ₂ applied to both the binarized regions S ₂ and S ₃ are obtained,
Areas S ₂ and S ₃ between the line r ₁ and the line r ₂ are obtained as shown by a black portion in FIG. 15 (B). The black area of FIG. 15B is thinned to obtain AB corresponding to the area S ₂ and CD corresponding to the area S ₃ . A region surrounded by ABCD shown in FIG. 15C is a region including a wire loop vertex.

Further, as shown in FIG. 15B, a line connecting the midpoint of AC and the midpoint of BD is defined as a wire direction sensor D _S1 . Each wire can be identified from the position data of the pad 64 or the ball 65 known in advance and the position where the wire direction sensor D _S1 crosses the pad 64 or the ball 65 in one screen, and the correspondence between each wire and the ball can be obtained. Can be taken.

Area AB including the detected wire loop vertices
Let DC be the window for detection of the wire loop vertex position. The wire loop vertex two-dimensional position detecting unit 144 obtains the window for each wire loop in one screen.

Next, the operation of the wire loop apex position detection unit 145, which is the wire loop apex position detection means, will be described. The wire loop apex position detection unit 145 is supplied with image data at each height of the imaging range from the image memory 142. Further, the window loop position data is supplied from the wire loop vertex two-dimensional position detection unit 144 for each wire loop.

In the image data at each height, the brightness evaluation amount E shown below is obtained for the image data in each window.

Wire loop of image data in window
Maximum brightness S near the apex _HAnd the minimum brightness
To S_LTo detect the half value S_MIs calculated by the following formula.

S _M = (S _H + S _L ) / 2 Next, in the vicinity of the wire loop apex, a half value width W at which the brightness is at least half value S _M is obtained, and the brightness in the window at that height is evaluated. The quantity E is calculated by the following formula.

E = (S _H −S _L ) / W FIG. 14B shows an example of the maximum brightness S _H , the minimum brightness S _L , the half value S _M , and the half value width W.

For each wire loop, the height of the image data that maximizes the evaluation amount E in the window (image pickup unit 1
The height of the focal plane 22) is defined as the height Z _P of the wire loop apex.

The two-dimensional position of the wire loop apex is obtained from the image data in the window at the height Z _P. FIG. 15F shows the brightness of the image data in the window at the height Z _P on the line passing through the vicinity of the vertex. Further, FIG. 15G shows data near the center when the data of FIG. 15F is binarized at the slice level S _M.

FIG. 15D shows the height Z_PWin in
Image data in the dough₃Scan in the direction and slice
Level S_MThe image binarized by is shown. The region containing the vertices
Area S_PIs. As shown in FIG.
Peak position O_P(X_P, Y _P) Is this area S_Pin
It is calculated as the position of the heart.

As described above, the wire loop vertex position detection unit 145 determines the three-dimensional position O of the wire loop vertex.
Detect _P (X _P , Y _P , Z _P ).

Next, the wire shape inspection section 146 which is the second wire shape inspection means will be described. The wire shape inspection unit 146 detects, from the wire loop vertex two-dimensional position detection unit 144 described above, for each bonding wire to be inspected,
The window position data corresponding to the area ABCD including the wire loop apex is supplied. Further, the wire loop apex position detection unit 145 is supplied with data on the three-dimensional position of the wire loop apex.

In the wire shape inspection unit 146, the supplied three-dimensional positions (X _P , Y _P , Z _P ) of the wire loop vertices of the inspection wire, the position data of the window including the wire loop vertices, and the reference wire. The shape of the inspection wire is inspected from the position data of the loop. That is, the quality of the shape is judged from the height of the wire loop, the position of the apex, the length of the apex, and the like.

Also, 3 of the wire loop vertices of the inspection wire
Dimensional position data, data of the window and the wire direction sensor, position data of the reference wire loop,
Based on the position data of the pad 64, the lead 62, etc., it is determined whether the direction in which the inspection wire extends, the distance between adjacent wires, etc. are within the reference range.

As described above, in the second embodiment, the oblique illumination portions 131 and 132 brightly reflect the vicinity of the wire loop apex of the bonding wire 63, and the image obtained by the image pickup portion 122. The area including the wire loop vertices is correctly detected as a window from the data. The height of the wire loop apex is detected from the difference in brightness in the window of the image data obtained by imaging at each height of the imaging range. Therefore, the shape inspection of the bonding wire can be performed more accurately based on the obtained three-dimensional position data of the wire loop apex.

FIG. 16 is an explanatory view of the lighting method of the third embodiment of the present invention. FIG. 16A shows the bonding wire 63.
16B is a plan view seen from above, FIG. 16B is a sectional view taken along line t in FIG. 16A, and FIG. 16C is an enlarged plan view near line t.

In the third embodiment, as shown in FIG.
The bonding wire 6
The angle with the horizontal in the same direction as 3 extends.
β₃, Β _FourLight L₃, L_FourIs irradiating. This angle β
₃, Β_FourIs slightly outside the apex of the bonding wire 63
The light reflected by the exposed regions 85 and 86 is reflected right above.
On the image pickup surface of the area sensor 124 of the image pickup unit 122.
Set to image.

As shown in FIGS. 16 (B) and 16 (C), the irradiation light L ₃ by the oblique illumination units 133 and 134 is
Regions 85 and 86 of L ₄ near the wire loop apex
The light reflected by is reflected right above, and the image pickup unit 12
The second objective lens 127 and the imaging lens 125 focus each other and form an image on the imaging surface of the area sensor 124.

On the other hand, of the light L ₃ and L ₄ emitted by the oblique illumination units 133 and 134, the light reflected in regions other than the regions 85 and 86 is reflected in directions other than directly above, and therefore the image pickup unit 12 is used.
No image is formed on the imaging surface of the second area sensor 124.

Therefore, the wire loop apex reflecting portion 8 which reflects the light L ₀ emitted by the coaxial incident illumination portion 121 right above.
4 and irradiation light L ₃ , L by the oblique illumination units 133, 134
_The areas 85 and 86 that reflect the light beam ₄ directly upward are the image pickup unit 1
Imaged brightly by 22. The areas 85 and 86
Is wider than the vertex reflecting portion 84.

The area sensor 124 is the coaxial epi-illumination unit 1.
The reflected light of the irradiation light L ₀ by 21 and the oblique illumination unit 133,
The irradiation lights L ₃ and L ₄ reflected by 134 output a signal corresponding to the brightness of the image formed on the image plane.

The depth of focus of the image pickup section 122 is set sufficiently shallower than the height of the wire loop of the bonding wire 63. Therefore, the image on the focal plane of the imaging unit 122 is clearly and brightly imaged, and the image on the off-focal plane is
The image is blurred and the brightness is reduced.

In the third embodiment, as in the second embodiment, the XYZ stage 151 moves the image pickup unit 122 upward in the image pickup range, and picks up images at fixed height steps. Thereby, a plurality of image signals at each height of the imaging range can be obtained.

A plurality of image signals at each height obtained by the area sensor 124 are converted into digital image data of 256 gradations by the image input section 141, and then image data corresponding to each height is stored in the image memory. Stored in 142.

Next, the operation of the wire loop vertex two-dimensional position detector 144 in the third embodiment will be described.
The wire loop vertex two-dimensional position detection unit 144 includes the vertex of the bonding wire 63 to be inspected by using the image data at the reference height of the wire loop vertex (reference height) supplied from the image memory 142. A two-dimensional area is obtained, and the two-dimensional position of the vertex is detected from this area.

FIG. 17 is a wire loop in the third embodiment.
The explanatory view of two-dimensional position detection processing is shown. Figure 17 (A) is based on
The original image of the bonding wire 63 at the sub-height is shown.
You In Figure 17 (A), the wire loop top is in focus
The area around the point is clearly imaged, and the image is out of focus.
The image of the pad 64, the ball 65, etc. is blurred. Figure 1
As shown in FIG. 7, by the illumination of the coaxial epi-illumination unit 121,
Wire loop apex S ₇And the pad is brightly imaged
There is. Also, by the illumination of the oblique illumination units 133 and 134,
Area S near the wire loop apex₈, S₉Is brightly imaged
Has been.

In this example, the brightness of the areas S ₈ and S ₉ is strongest, and the brightness of the area S ₇ is weaker than the brightness of the areas S ₈ and S ₉ . The other part of the bonding wire 63 is dark, and the pad 64 and the other part are intermediate brightness.

The original image shown in FIG.
Scan in the direction parallel to the line w that crosses the ear 63, and
S₈, S₉2 at a given slice level to identify
When digitized, as shown by the black portion in FIG.
Quantized area S₈And area S ₉Can be detected.

[0146] The area of the black portion shown in FIG. 17 (B) and thinning, and the center point B of the region S _8, the center point A of the region S ₉ is obtained. As shown in FIG. 17C, an appropriate length W _L considering the width of the bonding wire 63 is determined, and a region surrounded by FGHI including points A and B is obtained as a region including a wire loop vertex.

Further, as shown in FIG. 17B, A and B
A line connecting the two is defined as a wire direction sensor D _S2 . Within one screen,
The position data of the pad 64 or the ball 65 which is known in advance and the wire direction sensor D _S2 are set to the pad 64 or the ball
Each wire can be identified from the position where it crosses 5, and the correspondence between each wire and the ball can be obtained.

Area FG including the detected wire loop vertices
Let HI be the window for detecting the wire loop vertex position. In the third embodiment, the wire loop vertex two-dimensional position detection unit 144 obtains the window for each wire loop in one screen.

In the third embodiment, the wire loop vertex position detecting section 145 is supplied with image data at each height of the image pickup range from the image memory 142. Further, the position data of the window is supplied from the wire loop vertex two-dimensional position detection unit 144 for each wire loop.

In the third embodiment, the wire loop apex position detection unit 145, as in the second embodiment, has a height of the image data for which the evaluation amount E of the brightness of the apex portion in the window is maximum for each wire loop. The height (height of the focal plane of the imaging unit 122) is defined as the height Z _P of the wire loop apex.

The two-dimensional position of the wire loop vertex is the second real position.
Similar to the example, the height Z_PAt the window
It is calculated from the image data inside. As a result, the third implementation
The wire loop vertex position detection unit 145 of the example is a wire loop
3D position of the vertex_P(X _P, Y_P, Z_P) Is detected
It

In the third embodiment, the wire shape inspection unit 1
In 46, as in the second embodiment, the three-dimensional position (X _P , Y _P , Z _P ) of the wire loop apex of the inspection wire, the position data of the window including the wire loop apex portion, and the position of the reference wire loop. The shape of the inspection wire is inspected from the data. That is, the quality of the shape is judged from the height of the wire loop, the position of the apex, the length of the apex, and the like.

In addition, 3 of the wire loop vertices of the inspection wire
Dimensional position data, data of the window and the wire direction sensor, position data of the reference wire loop,
From the position data of the pad 64, the lead 62, etc., it is judged whether or not the direction in which the inspection wire extends, the distance between adjacent wires, etc. are within the reference range.

As described above, in the third embodiment, the oblique illumination portions 133 and 134 brightly reflect the vicinity of the wire loop apex of the bonding wire 63, and the image pickup portion 122.
The area including the wire loop vertices is correctly detected as a window from the image data obtained by imaging in. The height of the wire loop apex is detected from the brightness in the window of the image data obtained by imaging at each height of the imaging range. Therefore, the shape inspection of the bonding wire can be performed more accurately based on the obtained three-dimensional position data of the wire loop apex.

FIG. 18 is an explanatory view of the fourth embodiment of the present invention. As shown in FIG. 18, in the fourth example, a predetermined imaging range in the height direction (H ₀ −H _C ) including the reference height H _0.
~ (H ₀ + H _B ) is set. Of this imaging range, the allowable range of the height of the wire loop apex is (H ₀ −
H _A ) to (H ₀ + H _A ).

A plurality of image pickup section ranges are provided corresponding to the allowable range of the height of the wire loop vertices and other ranges. In the classification method shown in a, the allowable range ranges a ₂ and a ₃ and the outside range ranges a ₁ and a ₄ are provided. Further, in the classification method shown in b, the classification range b ₂ of the allowable range and the classification ranges b ₁ and b ₃ outside the allowable range are provided.

When the bonding wire 63 is picked up, the focal plane of the image pickup unit 122 is moved from the lower limit to the upper limit of the image pickup range while the shutter is not used, and the respective divided ranges are set for a predetermined time (for example, 1/30 seconds). ) Is imaged on one screen to obtain image data for each divided range.

In the fourth embodiment, the wire loop apex height detection unit 145, in the same manner as the second embodiment, in the image data for each divided range obtained as described above,
The evaluation amount E of the brightness of the apex is obtained in the window corresponding to each bonding wire 63. This brightness evaluation amount E
It is determined that the height of the wire loop is in the segmented range of the image data having the maximum.

In the fourth embodiment, the wire loop shape inspection unit
At 146, the wire loop height is as follows:
The quality of is judged. For classification method a, the above wire
Depending on the result of the judgment of the loop height,
A decision is made. Division range a ₂The height of the wire loop apex
The height of the wire loop is within the allowable range.
It is determined that the position is lower than the position. Division range a₃
If there is a wire loop vertex height in
The height is determined to be higher than the reference position within the allowable range.
Is determined.

When the height of the wire loop apex is in the section range a ₁ , it is determined that the wire loop height is at a low position outside the allowable range. When the height of the wire loop apex is in the section range a ₄ , it is determined that the wire loop height is at a high position outside the allowable range.

In the case of the classification method b, the quality is judged as follows according to the result of the above judgment of the wire loop height. When the height of the wire loop apex is in the section range b ₂ , the wire loop height is determined to be within the allowable range. When the height of the wire loop apex is in the section range b ₁ , the wire loop height is determined to be in a low position outside the allowable range. When the height of the wire loop apex is in the section range b ₃ , the wire loop height is determined to be at a high position outside the allowable range.

The number of sections and the length of each section range are set according to the required resolution in the height direction. The longer the division range and the smaller the number of divisions, the shorter the time required for the inspection.

As described above, in the fourth embodiment, the divided ranges corresponding to the allowable range of the wire loop height and the outside of the allowable range are provided, and the image data obtained by imaging for each divided range is used. Determine the wire loop vertex height. Therefore, the time required for the inspection can be shortened.

FIG. 19 is an explanatory view of the fifth embodiment of the present invention. FIG. 19A shows a side view of the oblique illumination unit and the imaging unit, and FIG. 19B shows a plan view of the oblique illumination unit and the imaging unit. In the fifth embodiment, the irradiation angle of the oblique illumination can be adjusted to an appropriate angle according to the size and shape of the bonding wire to be inspected.

In FIG. 19, the oblique illumination unit 133 is composed of a plurality of lights 133 _{1 to} 133 ₅ with different irradiation angles, and the oblique illumination unit 134 is a plurality of lights 134 _{1 with} different irradiation angles.
～134 consisting of _5. As shown in FIG. 19, in each of the oblique illumination sections 133 and 134, the irradiation section is formed by a curved surface corresponding to the wire direction. The irradiation angle adjusting means includes a wire loop vertex position detection signal determination unit 161 and an illumination controller 162.

Wire loop vertex position detection signal determination unit 16
1 determines whether or not the irradiation angle is appropriate from the image data obtained by irradiating the bonding wire 63 serving as a reference at a certain irradiation angle and capturing the image with the imaging unit 122. The illumination controller 161 generates an illumination selection signal for selecting the illumination of the illumination units 133 and 134 according to the determination result.
Supply to.

The illumination controller 162 selects the optimal illumination from the plurality of illuminations of the oblique illumination units 133 and 134 based on the illumination selection signal supplied from the wire loop vertex position detection signal determination unit 161.

Next, the operations of the wire loop apex position detection signal determination unit 161 and the illumination controller 162 will be described. FIG. 20 is an explanatory diagram of the evaluation amount for irradiation angle determination when oblique illumination is performed in the direction crossing the wire loop.

FIG. 20A is an original image in the case of the most general wire loop having a loop vertex on the line R _P1 .
20B is an image obtained by binarizing FIG. 20A at a predetermined slice level. In FIG. 20 (B), the black portion indicates the bright portion of the loop apex. The length of this bright portion is L, and the distance from the predetermined position (the position of the center of the ball in FIG. 20B) is L _P. This length L and distance L _P
Is the evaluation amount for determining the irradiation angle.

[0170] When 20 of the wire loop (A), the evaluation quantity L, with L _P, determines whether the irradiation angle is large, small or, appropriate. Evaluation value L is minimized, when the evaluation quantity L _P is approximately equal to the reference made wire loop vertex position, the irradiation angle is appropriate. Based on the evaluation amount, the illumination of the illumination units 133 and 134, which has the appropriate irradiation angle, is selected and the illumination selection signal is generated.

In FIG. 20C, the vicinity of the wire loop vertex is
The position of the apex is gentler than that of FIG. 20 (A).
Shows the original image for a wire loop away from the position
You FIG. 20 (D) shows a predetermined slice record of FIG. 20 (C).
This is a binarized image with a bell. In FIG. 20D, black
The part indicates the bright part of the loop apex. This bright part
End of minute and line R_P1Distance to L_DAnd the specified position (Fig.
In 20 (B), the distance from the position of the center of the ball) is L_P
And In the case of the wire loop of FIG. 20 (C), L _P+ L
_DIs the evaluation amount for adjusting the irradiation angle.

Wire loop vertex position detection signal determination unit 16
In the case of the wire loop of FIG. 20 (C), the evaluation amount L _P + L _D is used to determine whether the irradiation angle is large, small, or appropriate. The irradiation angle becomes appropriate when the evaluation amount L _P + L _D L becomes substantially equal to the reference value. Illumination units 133, 1 whose irradiation angles are appropriate based on the evaluation amount
34 lights are selected to generate a light selection signal.

The illumination controller 162 selects the illumination of the illumination units 133 and 134 according to the illumination selection signal supplied from the wire loop vertex position detection signal determination unit 161, and adjusts the irradiation angle.

FIG. 21 is an explanatory view of the evaluation amount for angle adjustment when the wire is obliquely illuminated in the extending direction. Figure 21
21A is an original image when the irradiation angle is appropriate in the case of the most common wire loop having a loop vertex on the line R _P2 , and FIG. 21B is a predetermined slice of FIG. 21A. It is an image binarized by level.

In FIG. 21B, the black portion shows the bright portion of the loop apex. Let L ₁ and L ₂ be the distances from the wire loop vertices of this bright portion, and the predetermined positions (in FIG. 21,
The distance from the center position of the ball) is L _P. The distances L ₁ and L ₂ are used as the evaluation amount for adjusting the irradiation angle.

FIG. 21C is an original image when the irradiation angle is invincible and the position slightly away from the apex becomes bright with the same wire loop as FIG. 21A. Is
It is an image obtained by binarizing FIG. 21C at a predetermined slice level. As shown in FIG. 21D, in this case, the evaluation amounts L ₁ and L ₂ are large.

FIG. 21 (E) is the same wire loop as in FIG. 21 (A), and the original image in the case where the irradiation angle is invincible and the position greatly apart from the apex becomes brighter.
21A is an image obtained by binarizing FIG. 21E at a predetermined slice level. As shown in FIG. 21 (F), in this case, the evaluation amount L ₂ becomes larger than that in FIG. 21 (D). Also,
Since the inclination of the wire loop in the bright portion corresponding to L ₁ is gentle, the evaluation amount L ₁ becomes larger than L ₂ .

Wire loop vertex position detection signal determination unit 16
In 1, the evaluation amounts L ₁ and L ₂ are used to determine whether the irradiation angle is large, small, or appropriate. Evaluation amount L ₁ ,
The irradiation angle becomes appropriate when L ₂ becomes substantially equal to the reference value shown in FIG. 21 (B). Based on the evaluation amount, the illumination of the illumination units 133 and 134, which has the appropriate irradiation angle, is selected and the illumination selection signal is generated.

The illumination controller 162 selects the illumination of the illumination units 133 and 134 according to the illumination selection signal supplied from the wire loop vertex position detection signal determination unit 161, and adjusts the irradiation angle.

As described above, in the fifth embodiment, the irradiation angle adjusting means is provided, and the irradiation angle of the oblique illumination can be optimally adjusted based on the image data obtained by imaging.

[0181]

As described above, according to the invention of claim 1,
The loop apex of the bonding wire is obtained from the image data obtained by capturing the image from directly above the bonding wire by the first image capturing means and the image data obtained by capturing the image from diagonally above the bonding wire by the second image capturing means. Since the three-dimensional position can be detected, the shape of the bonding wire can be inspected more accurately.

According to the fifth aspect of the present invention, the fourth illuminating means brightly reflects the vicinity of the loop apex of the bonding wire so that the area including the wire loop apex is correctly detected from the image data taken from directly above. However, since the height of the wire loop apex is detected from the brightness in the area of the image data at each height of the imaging range, the bonding wire is detected based on the obtained three-dimensional position data of the wire loop apex. The shape inspection can be performed more accurately.

According to the tenth aspect of the present invention, the height of the wire loop apex is determined by using the image data obtained by picking up each section of the plurality of height-direction image pickup sections as one screen. Therefore, the time required for the inspection can be shortened.

According to the eleventh aspect of the present invention, the irradiation angle adjusting means optimally adjusts the irradiation angle of the fourth illuminating means based on the image data obtained by imaging by the third imaging means. You can

[Brief description of drawings]

FIG. 1 is a configuration diagram of a main part of a first embodiment of the present invention.

FIG. 2 is an overall configuration diagram of a first embodiment of the present invention.

FIG. 3 is a layout diagram of an illumination / imaging system according to the first embodiment of the present invention.

FIG. 4 is an explanatory diagram of an illumination / imaging system according to a third embodiment.

FIG. 5 is an explanatory diagram of an imaging position on a reference wire.

FIG. 6 is an explanatory diagram of an imaging position on a wire that is deviated from a reference position.

FIG. 7 is an explanatory diagram of a method for calculating the height of a wire loop vertex.

FIG. 8 is an explanatory diagram of a process of obtaining an image formation position on an image pickup surface immediately above.

FIG. 9 is an explanatory diagram of a process of obtaining an image forming position on an oblique image pickup surface.

FIG. 10 is a configuration diagram of a main part of a second embodiment of the present invention.

FIG. 11 is an overall configuration diagram of a second embodiment of the present invention.

FIG. 12 is a perspective view of an illumination / imaging system according to a second embodiment of the present invention.

FIG. 13 is an explanatory diagram of a lighting method according to a second embodiment of the present invention.

FIG. 14 is an explanatory diagram of an original image having a reference height according to the second embodiment.

FIG. 15 is an explanatory diagram of a wire loop vertex two-dimensional position detection process in the second embodiment.

FIG. 16 is an explanatory diagram of an illumination method according to a third embodiment of the present invention.

FIG. 17 is an explanatory diagram of a wire loop vertex two-dimensional position detection process in the third embodiment.

FIG. 18 is an explanatory diagram of the fourth embodiment of the present invention.

FIG. 19 is an explanatory diagram of the fifth embodiment of the present invention.

FIG. 20 is an explanatory diagram of an accuracy adjustment evaluation amount when oblique illumination is performed in a direction that traverses a wire.

FIG. 21 is an explanatory diagram of an evaluation amount for accuracy adjustment when oblique illumination is performed in the wire direction.

FIG. 22 is an explanatory diagram of a bonding wire shape.

FIG. 23 is an explanatory diagram of an optical system of a conventional bonding wire inspection device.

FIG. 24 is an explanatory diagram of a conventional bonding wire inspection method.

FIG. 25 is a diagram showing various states of a bonding wire.

[Explanation of symbols]

 11-15 Illumination / imaging system 21 Coaxial epi-illumination unit 22 Imaging unit 23 Coaxial illumination 24 Area sensor 25 Imaging lens 26 Half mirror 27 Objective lens 31 Oblique illumination unit 32 Imaging unit 33 Coaxial illumination 34 Area sensor 35 Imaging lens 36 Half mirror 37 Objective lens 40 First image data storage unit 41 Image input unit 42 Image memory 43 Wire loop vertex three-dimensional position detection unit 44 Wire shape inspection unit 46 Control unit 47 Reference wire loop vertex position data 48 Frame feeder 49 Stage system 51-55 XYZ stage 60 IC 61 chip 62 lead 63 bonding wire 64 pad 65 ball 121 coaxial epi-illumination unit 122 image pickup unit 123 coaxial illumination 124 area sensor 125 imaging lens 126 half mirror 127 objective lens 131-134 Oblique Illumination Unit 140 Second Image Data Storage Unit 141 Image Input Unit 142 Image Memory 144 Wire Loop Vertex Two-Dimensional Position Detection Unit 145 Wire Loop Vertex Position Detection Unit 146 Wire Shape Inspection Unit 148 Frame Feeder 149 Stage System 151 XYZ stage 161 Wire loop vertex position detection signal determination unit 162 Lighting controller

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Takashi Fuse 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited

Claims (11)

[Claims] 1. A bonding wire inspection apparatus which stores image data of a bonding wire (63) by an image data storage means and inspects the shape of the bonding wire by using the image data, directly above the bonding wire (63). First illuminating means (21) for illuminating the loop apex part of the bonding wire (63) brightly by irradiating light from the first and imaging means (1) for imaging the reflected light right above the bonding wire (63) ( 22), second illuminating means (31) for illuminating light obliquely above the bonding wire (63) to brighten the loop apex of the bonding wire (63), and the second illuminating means (31). A second image of reflected light of the irradiation light of the bonding wire (63) at the loop apex of the bonding wire (63) at a position facing the second illumination means (31). Image pickup means (32), image data corresponding to the output image signal of the first image pickup means (22) is stored, and image data corresponding to the output image signal of the second image pickup means (32) is stored. The two-dimensional position of the loop apex of the bonding wire (63) is detected using the first image data storage means (40) and the image data corresponding to the output image signal of the first imaging means (22), The image data corresponding to the output image signal of the first image pickup means (22) and the second image data.
Wire loop apex three-dimensional position detecting means (43) for detecting the three-dimensional position of the loop apex of the bonding wire (63) by using image data corresponding to the output image signal of the image capturing means (32), First wire shape inspection means (44) for inspecting the three-dimensional position and shape of the bonding wire (63) based on the data of the wire loop apex three-dimensional position supplied from the apex three-dimensional position detection means (43). A bonding wire inspection device comprising: 2. The second illuminating means (31) can select the irradiation direction of the bonding wire (63) to the loop apex from a plurality of directions, and the second imaging means (3).
2. The bonding wire inspection apparatus according to claim 1, wherein 2) is capable of selecting a direction for capturing an image in accordance with a direction of reflected light determined by the irradiation direction selected by the second illuminating means (31). 3. The optical axis of the second illumination means (31) and the second imaging means (32) is in the same direction as the bonding wire (63) to be inspected. Bonding wire inspection device. 4. The first imaging means (22) based on three-dimensional position data of a loop apex of a reference bonding wire.
And a stage for adjusting the positions of the first image pickup means (22) and the second image pickup means (32) so that the focal planes of the second image pickup means (32) coincide with the loop vertices of the reference bonding wire. The bonding wire inspection apparatus according to claim 1, wherein (51 to 55) are provided. 5. A bonding wire inspection device for storing image data of a bonding wire (63) by an image data storage means and inspecting the shape of the bonding wire (63) using the image data. The third illuminating means (121) for illuminating the loop apex of the bonding wire (63) brightly from directly above the bonding wire (63) and the bonding wire (63) by illuminating light obliquely above the bonding wire (63). 4) a fourth illuminating means (131, 132) for brightly illuminating the vicinity of the loop apex, and a focal depth which is sufficiently shallow compared to the height of the loop apex of the bonding wire (63) and is focused by the stage (151). The height of the surface is set, and the bonding wires (6) are set at a plurality of heights within the imaging range including the reference height.
Third image pickup means (12) for picking up light reflected right above by 3) and outputting a plurality of image signals at the plurality of heights.
2) and second image data storage means (140) for storing a plurality of image data corresponding to a plurality of image signals at the plurality of heights supplied from the third image pickup means (122).
And a wire loop vertex two-dimensional position detecting means (144) for detecting a two-dimensional rough position of the loop vertex of the bonding wire (63) using the image data supplied from the second image data storage means (140). ) And wire loop vertex position detecting means (145) for detecting the position of the loop vertex of the bonding wire (63) using the plurality of image data at the plurality of heights and the data of the two-dimensional approximate position of the loop vertex. A second wire shape inspection means (146) for inspecting the three-dimensional position and shape of the bonding wire (63) based on the data of the wire loop apex position supplied from the wire loop apex position detection means (145). A bonding wire inspection apparatus comprising: 6. The fourth lighting means (131, 132)
The bonding wire inspection apparatus according to claim 5, wherein the light is irradiated in a direction traversing the bonding wire (63). 7. The fourth lighting means (131, 132)
6. The bonding wire inspection apparatus according to claim 5, wherein the light is irradiated in a direction substantially the same as the extending direction of the bonding wire (63). 8. The bonding wire inspection apparatus according to claim 5, wherein the wire loop vertex two-dimensional position detecting means (144) detects the extending direction of the bonding wire (63). 9. The fourth illumination means (131, 132)
6. The bonding wire inspection apparatus according to claim 5, wherein the light is emitted from two directions facing each other with the bonding wire (63) interposed therebetween. 10. The third image capturing means (122) captures an image of each segmented range of the plurality of segmented image capturing ranges in the height direction while moving the focal plane, and images each segmented range. 6. An image signal for one screen is obtained.
Bonding wire inspection device described. 11. The second image data storage means (14)
6. An irradiation angle adjusting means (161, 162) for adjusting the irradiation angle of the fourth illuminating means (131, 132) is further provided based on the image data supplied from (0). Bonding wire inspection device described.