JPS62127617A - Inspecting instrument for linear body - Google Patents

Abstract

PURPOSE:To detect whether a wire loop is in a proper shape or not by storing patterns of the three primary colors R.G.B obtained by irradiating illuminating light of the three primary colors on a linear materials body changing an angle in image memories via an image pickup means and measuring the distribution and length of the patterns of the three primary colors and calculating the height of the wire loop. CONSTITUTION:A linear image of the body 6 to be inspected by ring illumina tion in a loop state of R.G.B is picked up on image by the image pickup means 10 via a lens system 9 and signals of the three primary colors R.G.B are added to an analog-digital conversion circuit 11 and digital linear image data are stored in the image memories 12R, 12G and 12B of R.G.B. The stored data are added to an inspection window reader 13 and a window is set based on data from an inspection window instruction circuit 14 and the distribution and length of R.G.B of the linear image are measured by a wire-loop inspection circuit 15 and the height of the part is calculated. Then, a defect of the wire loop is decided by comparing it with the normal pattern loop and the defected linear image is displayed on a defect display device 16.

Description

[Detailed Description of the Invention] [Summary of the Invention] The present invention relates to a linear object inspection device, which applies red (R), blue (B), and green (G) illumination light to a linear object from an oblique angle. The reflected light is imaged by an imaging means from directly above the linear object, and outputs corresponding to the R, G, and H outputs of the imaging means are stored in an image memory, and from these image data. The present invention provides a linear object inspection device that detects defects in wire loops by detecting the height of the linear object.

[Industrial application field]

The present invention relates to a linear object inspection device, and more particularly to a linear object inspection device for two-dimensionally detecting the height shape of a bonding wire or the like.

[Conventional technology]

Conventionally, linear object inspection equipment for inspecting the bonding condition of wires used to connect IC (integrated circuit) chips and package leads, i.e., the waviness and sagging of wires, has been difficult to automate and difficult for workers to visually inspect. It was the current situation that I relied on. The bonding state of such a conventional bonding wire will be explained with reference to FIGS. 9 to 11. FIG. 9 is a perspective view showing a wire-bonded IC, FIG. 10 is a side view of defective wires bonded between the IC chip and package leads, and FIG. 11 is a schematic side view of the IC. It is a line side view when the wire bonded between the chip and the pa-no-cage glue-F is normal, and in FIG. A wire δ is bonded between -F' and 4 formed on the side. Examples of such bonded defects are shown in Fig. 10 [al], where the wire has become loose and is hanging downward, and Fig. 10 (tb+) is where the wire has become loose and bent in one direction. FIG. 10 FC+ shows the case where there is no slack at all. FIG. 11 shows a properly wire bonded side view. In this case, it is stretched in an appropriate bow shape without any undulations or sagging.

[Problem that the invention seeks to solve]

The one shown in Figure 10 (taj) has the ground line on the bottom, so there is a possibility that wires such as gold wires may short-circuit. There is a possibility that the curved part will come into contact with the adjacent wire and cause a defect. It is determined that

Inspecting such a wire loop shape from the side as shown in FIGS. 10 and 11 means that the adjacent wire
As shown in the figure, this is not possible due to the extremely dense arrangement of the wires, and no device has currently been proposed to automatically inspect the wire shape. For this reason, the inspection is performed visually by the operator, which has the drawback of operator oversight and variations in inspection standards.

[Means for solving problems]

The present invention has been made in view of the above drawbacks, and its purpose is to obtain a linear object inspection device that automatically detects the wire loop defect described above. an illumination means for projecting a plurality of illumination lights onto a linear object at different illumination angles; an imaging means for separating and imaging the light into a plurality of video signals; reflection of the linear object by the plurality of floodlights; image memory means for digitizing the output of the imaging means and storing it in a plurality of image memories; and determining the inclination of the linear object based on the output of the image memory and the height of the linear object loop based on the length corresponding to the inclination. This is achieved by a linear object inspection device characterized by comprising a wire loop inspection means for detecting.

[For production]

The linear object inspection device of the present invention is based on the fact that when a linear object is placed at an angle of θ/2 with respect to a reference plane, when illumination light is applied obliquely, it will be reflected at an angle of θ. The three primary color patterns obtained by irradiating the linear object with the three primary color illumination lights of R, G, and B at different angles are stored in the image memory via the imaging means, and the pattern distribution and length of the three primary colors at this time are stored in the image memory. By measuring the wire loop □
To obtain a linear object inspection device which detects whether a wire loop has a proper shape by determining the height.

〔Example〕

Hereinafter, the linear object inspection apparatus of the present invention will be described in detail with reference to FIGS. 1 to 8.

Fig. 1 is a system diagram of the linear object inspection device of the present invention, Fig. 2 is a conceptual diagram of the illumination system shown in Fig. 1, and Fig. 3 is a detailed explanation of the present invention, the relationship between the linear object and the imaging means. Perspective view showing 4th
Figures Tal~+d+ show the distribution of the three primary color image memory on a linear object in a normal wire loop shape, and Figure 5 explains the process for forming a void in the three primary color image memory and measuring the reflection length of the three primary colors. 6 is an explanatory diagram for determining the height of the wire from the reflection lengths of the three primary colors determined in FIG. 5, and FIG. 7 is a conceptual diagram showing another embodiment of the illumination system of the present invention. FIG. 8 is a circuit diagram showing details of the wire loop inspection circuit shown in FIG. 1.

In FIG. 1, reference numeral 6 indicates an object to be tested such as the bonded IC described in FIG.
The test object 6 is illuminated.

The projector 7 is composed of R, G, and H loop-shaped ring lights, which will be described later, and is connected to a light source 8 through an optical fiber. Reference numeral 9 indicates a lens system, and the line image of the object to be inspected 6 is captured by the lens system 9.
The three primary color signals of R, G, and H are applied to an analog-digital conversion circuit 11 to convert the analog line image into digital data, and the digital line image data is converted into digital line image data. R, G, B
The data stored in each image memory 12R, 12G, 12B is added to the inspection window successive device 13, and the window setting is performed based on the data from the inspection window instruction circuit 14. Then, the next wire loop inspection circuit 15 measures the R, G, and B distribution lengths of the line image, calculates the height of that part, and determines a defect by comparing it with a normal pattern loop and displays the defect display device. 16
The defect line image is displayed.

Details of the above-mentioned light projector 7 and light source will be explained with reference to FIG. 2.

The projector 7 has a cylindrical shape as shown in the second concave curved view,
It has a central hole 7a in the center, and the lower surface thereof is a mortar-shaped conical part 7.
b, and the optical fiber bundle 8a is arranged so that the centerline 17 of the lens system and the centerlines of the center hole 7a and the conical portion 7b coincide with each other.

One end of each of 8b and 8c is formed into a ring shape within the projector 7, and illuminates the object 6 to be examined in a ring shape. Furthermore, R,G.

The ring-shaped arrangement position for B is such that the angle of irradiation to the test object 6 arranged on the center line 17 is θ3. They are arranged differently as shown by θ2° θ1. For this reason, the optical fiber 18 from each ring-shaped fiber bundle is directed toward the inclined surface of the conical portion 7b at θ3. R, G by pulling it out in a loop at the angle of θ2°θ1.

A light projection surface 19 corresponding to B is formed on the inner surface of the conical portion 7b.

The other ends of the optical fiber bundles 8a, 8b, and 8c are respectively a red transmission filter 8Ra that transmits only red light and blocks other colors, and a green transmission filter 8Gb that transmits only green light and blocks other colors.
, a blue transmission filter 8 that transmits only blue and blocks other colors.
Bc, and each of these filters has a red light source 8R,
Green light SSC.

Illumination light is provided from a blue light source 8B. In the above embodiment, the optical fiber 18 is looped from the R, G, and H optical fiber bundles to the conical portion 7b at an angle of θ3. The projection plane was formed by deriving the angles θ2° and θ3, but as shown in FIG. 7, the optical fiber bundle 8a,
Branch optical fiber bundles for two sets from 8b and 8c,
The light projection surface 19 having a different and finer illumination angle θ may be formed from a total of six sets of R, G, and 'B bundles.

Further, the configuration of the wire loop detection circuit 15 shown in FIG. 1 is shown in FIG. 8. The output from the detection window readout circuit 13 is applied to a wire length measuring circuit 20 to measure the length l of the wire, that is, the object to be tested, and further, based on the output, an inclination determination circuit 21
Find the wire inclination θ/2, use these lengths and wire inclinations to calculate the wire height h in the wire height calculation circuit 22, calculate the wire loop in the wire loop calculation circuit 23,
The wire loop comparison circuit 25 compares the reference value with the reference loop memory 24 in which the normal wire loop height value is stored, and compares the output to see if they match within the allowable range of the reference loop. If so, the signal is output to the defect display device 16 at the next stage.

The operation of the above-mentioned linear object inspection apparatus of the present invention will be described in detail with reference to FIGS. 3 to 6. FIG. 3 explains the operating principle of the present invention, and shows a linear object (wire) as the object to be examined 6.
5 is tilted by θ4/2, and if the wire is a mirror surface like a gold wire, if the illumination light 26 is irradiated obliquely, the reflected light 27 will be reflected at an angle θ4, so it will be on this reflected optical axis. By bringing the center line 17 of the lens system 9 to , the inclination of the wire 5 can be determined. In other words, by varying the incident angle of the illumination light 26, the reflection position changes depending on the curvature of the wire 5. If the bonded wire 5 forms a loop with an ideal curvature as shown in FIG. 4, the illumination light R as shown in FIG.
, G, and B at an angle θ1. In the case of irradiation at θ and θ3, a line image of the wire 5 taken from the true angle by the color TV camera 10 through the lens system 9 is as shown in FIG. 4 fbl in the 8-image memory 12B shown in FIG. 1. to 2
Similarly, in the 6-image memory 12G, the portions 9B and 29B' shine brightly in blue, as shown in FIG. 4(C).
c', 29G' portions shine brightly in green, and in the R image memory l 2 R, the 29R portion shines brightly in red as shown in Figure 4 fd+.
B, G, and R ray images 28B as shown in el.

28G and 28R, the inspection window 308.30G of B, G, and R is set by the inspection window instruction circuit 14 shown in FIG.

Set 30R. Next, the inspection window 3 is detected by the inspection window successive circuit 13.
Read out 0B, 30G, 30R, and see Fig. 5 tea, (
d+, (Slice level 31B, 31G at the center position of the B, G, and R ray images read out as shown in fl.

31R and wire loop inspection circuit 1 shown in FIG.
r3.5 in the wire length measuring circuit 20. G, R bright parts 29B, 29B', 29c, 29c'.

29G", 29R length ff4. 7!, , 7!
,, 1. .

7! Add 2 to 1. In this case, at the starting point of the bonding wire, the bright part is 29G as shown in tel in Figure 5.The bright part is 29R in Figure 5 (as shown in il). Figure 5 (al
There is regularity according to the reference line image, such as the 29B section shown in Figure 5 fcl, the 29G'' section shown in Figure 5 fcl, and the 29B' section shown in Figure 5 tel, and G→R→G→B→G. -+B, and conversely, from the bonding wire end point, it changes to B-+G-+
B-IG→R→G changes in the order of levers R, G, 8
By reading out image memories 2R112G and 12F3, the positions and lengths can be counted.

Next, in the tilt determination circuit 21, the bright portion of the line image is transferred from the 0 image memory indicated by 13 to the 8 indicated by
There is an upward slope up to the image memory, but in the process of moving from the 8 image memory indicated by 7!4 to the Ils, -T: not 0 image memory, there is a downward slope, so this G-B-G state is detected. This determines whether the slope is positive or negative.

In other words, the slope sign α-1 or -1 is G-+B-+G→B
In the case of α-1, in the case of G-hB-+G→R, α=-1
shall be.

Next, the wire height calculation circuit 22 calculates the length J of the wire loop, which is the angle of the above-mentioned slope sign α and the polygonal line.

.about.16, the value at a predetermined position is sequentially sampled and determined from the following equation.

Here, the height of the wire loop 5 at one position, not shown at the angle in FIG. 6, is 7! , +ff2+A3+β4〈β≦7! ,+
Since A2+13+7!5, h B) = (7!, jan 25°+12 tan 40”
+ 13jan 25' + 14tan 5')<
p <7!1+7!2+7!3+n4) ) tan
It can be found at 25°.

In this way, the length of the wire is 1. The height of each point of the wire can be calculated from the 1st rotation θ8 inclination angle sign α of the wire and these sampling points. The wire loop calculation circuit 23 calculates the loop shape of the wire 5 based on the length and height of the wire 5 and outputs it to the wire loop comparison circuit 25.
The length and height of the defect are compared and if they are not within the allowable range, they are displayed on the defect display device.

〔Effect of the invention〕

Since the present invention is constructed and operates like a ridge, the linear object is irradiated with illumination light of different wavelengths obliquely, and the object to be inspected is
-], it is possible to provide a linear object inspection device that can automatically detect abnormalities in the wire loop.

[Brief explanation of drawings]

Fig. 1 is a system diagram of the linear object inspection device of the present invention, Fig. 2 L
3 is a schematic diagram for explaining the present invention in detail, Figure 4 is a side view of the ear loop from fat L, Figure 4 is a side sectional view of the lighting system of the present invention, G.
A plan view of the line image pattern of the R image memory, FIG. A conceptual diagram for determining the line length by slicing a line image within a window, FIG. 6 is an explanatory diagram for determining the height h from the wire length, slope, and slope sign of the present invention, and FIG. 7 8 is a circuit diagram illustrating details of the wire loop inspection circuit shown in FIG. 1; FIG. 9 is a conventional IC chip bonding circuit; Fig. 10 is a side view showing an example of defective bonding; Fig. 11 is a side view showing a normal example of bonding. 1... IC chip; 5... Wire, 7... Light emitter, 8... Light source, IO... Imaging means, 12R, 12G, 12B... R, G, B coarse image memory, 13... Inspection window readout circuit, 15...・Wire loop inspection circuit, 20... Wire length measurement circuit, 21... Inclination determination circuit, 22... Wire height calculation circuit, 23... Wire loop calculation circuit, 24... Reference loop memory , 25...Wire loop comparison circuit.
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Claims (4)

[Claims] (1) Illumination means that projects a linear object, which is a test object, with multiple illumination lights at different illumination angles, and separates and images the reflected light of the linear object from the multiple floodlights into multiple video signals. image capturing means for digitizing the output of the image capturing means and storing it in a plurality of image memories; A linear object inspection device comprising a wire loop inspection means for detecting the height of the object loop. (2) Linear object inspection according to claim 1, wherein the illumination means has red, green, and blue light projection surfaces in a loop shape that project light onto the linear object at different angles. Device. (3) The linear object inspection apparatus according to claim 1, wherein the illumination means has a plurality of sets of red, green, and blue light projection surfaces that project light onto the linear object at different angles. . (4) The wire loop inspection means includes a wire length measurement circuit that measures the length of the wire, an inclination determination circuit that determines the inclination of the wire, and calculates the wire height based on the wire length and the inclination of the wire. A wire height calculation circuit, a wire loop calculation circuit that calculates a wire loop, a reference loop memory means that stores a reference loop, and a wire loop comparison means that compares the outputs of the wire loop calculation circuit and the reference loop memory means. A linear object inspection device according to claim 1, characterized in that: