JPH0654219B2 - Linear object inspection device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a linear object inspection apparatus, and more particularly to improvement of an adjacent distance measuring device.

(2) Background of technology In the recent assembling process of ICs and the like, high-speed assembling and processing of ICs is possible by an automatic assembling device, and ICs are efficiently manufactured and assembled. However, the inspection after IC processing has not been completely automated yet, and depends on the visual inspection of the operator, so there is a problem that the inspection result varies due to individual differences.

(3) Prior Art In order to solve the above-mentioned problems of inspection, the present applicant has previously proposed a linear object inspection device (Japanese Patent Application No. 58-16904 / Japanese Patent Laid-Open No. Sho 60-16904).
59-150433). The measuring method by such an automatic inspection means will be described in detail with reference to FIGS. 7 to 10.

FIG. 7 is a perspective view showing a relationship between a conventional IC chip and a package after wire bonding processing. Reference numeral 1 is a circuit electrode or pad formed on the IC chip 4.
The leads 2 extending to the outside of the package and the pads are bonded by wires 3 so as to be electrically connected. When such a wire bonding state, that is, an abnormal state such as contact or proximity of the wire, is to be inspected by the linear object inspection device, the wire imaging plane of FIG.
As shown in the figure, the distance between adjacent wires 3a and 3b is X
Abnormal conditions such as contact and proximity are detected by measuring in the axial direction (left-right direction in the figure. In the figure, the distance l _{X in the} X-ray direction is shown) or in the Y-axis direction (vertical direction in the figure). ing. In performing such abnormality detection, for example, the contours of each wire are detected in advance, the center of the left and right contours or the center of the upper and lower contours (contour center) is obtained, and the contour center of one wire 3a The distance in the X-axis direction or the Y-axis direction to the contour center of the wire 3b is measured, and this distance is measured.
The distance between a and 3b (for example, l _X above).

As a method for detecting the contour of the wire, a dedicated contour detection pattern for detecting the left, right, upper, and lower contours of the wire is used, and these contour detection patterns are laid along the captured contour of the wire in the left-right or up-down The contour is detected by moving to. For example, in order to detect the left and right contours of the wires wired in the substantially Y-axis direction (generally the vertical direction in FIG. 8) as shown in FIG. 8, as shown in FIGS. 9 (a) and 9 (b). A left contour detection pattern and a right contour detection pattern formed of a 3 × 3 matrix pattern are used to detect the left and right contours of the wire 3 in a predetermined procedure. 9th
In the left-side contour detecting means shown in FIG. 7A, the detection unit L located at the center of the left-side contour detection pattern is moved sequentially along the left-side contour of the wire 3 as L ₁ → L ₂ → L _3. It is moved, and the X and Y coordinates of the detection unit L at that time are set as the coordinates indicating the position of the left contour of the wire 3. In order to sequentially move the central detector L such as L ₁ → L ₂ → L _3, etc., eight detectors a ₁ , a ₂ , ...
..., prioritize as that number a _8, this priority in accordance with the presence or absence of the wire 3 (i.e. the image data is "1" or "0" or) continue to detect the first detection wires 3 The position of the detected portion is set as the position to which the central portion L should move next. In FIG. 9 (a), when the detection unit L is at the position L ₁ , the detection unit a ₁ first detects “1”, so that the next movement position L ₂ of the detection unit L is the detection unit a 1 described above. Position ₁ Similarly, when the central portion L is at the position L ₂ , the detecting portion a ₂ first detects “1”, so that the next moving position L ₃ of the detecting portion L is the same as the position of the detecting portion a ₂ . Become. Fig. 9
In the right contour detection procedure shown in (b), the detection unit R at the center of the right contour detection pattern is moved along the right contour of the wire 3 by R ₁
→ R ₂ → R ₃ etc. are sequentially moved, but only the arrangement of surrounding detection parts a ₁ , a ₂ , ..., A ₈ is different, and the other is left side contour detection. Follow the same procedure.

(4) Problems of Prior Art However, according to the linear object inspection device having the above-mentioned configuration,
Bonding wires 3a and 3b at the corners of the IC chip 4 and the IC package lead 2 in the figure are radially extended from the pad 1 to the lead 2 as shown in the enlarged plan view of FIG. Therefore, wire 3
While the measured distance in the X-axis direction between a and 3b is l _{X 1} , the actual distance is the value indicated by l, and there is a large difference between the measured distance l _{X 1} and the actual distance l. Ended up, Y
Since the same can be said for the measurement distance in the axial direction, there is a drawback that it does not match the actual situation.

(5) Object of the invention The present invention has been made in view of the above-mentioned drawbacks, and a linear object capable of accurately and automatically measuring the distance between adjacent linear objects of the wire at the corner connecting the IC chip pad and the IC package lead. The purpose is to provide an inspection device.

(6) Configuration of the Invention According to the invention, the above object is to provide an image pickup means for picking up two linear objects adjacent to each other as an object to be inspected, and an analog picked up image obtained by the image pickup means as a digital image. An analog / digital converting means for converting into a digital image, an image memory for storing the digital image, a distance measuring means for measuring a distance between the two linear objects based on the digital image stored in the image memory, and the distance. In the linear object inspection device, comprising: an abnormality detecting unit that detects an abnormal state of the linear object based on a measurement result of the measuring unit, the distance measuring unit starts each inspection of the two linear objects in the digital image. A centerline calculating means for obtaining a centerline which is a straight line connecting a center between points and a center between inspection end points, and a distance between the two linear objects perpendicular to the centerline. It is achieved by providing a linear object inspection device characterized in that it has a distance calculating means.

(7) Embodiments of the Invention Hereinafter, one embodiment of the present invention will be described in detail with reference to FIGS.

FIG. 1 is a system diagram of a linear object inspection apparatus of the present invention, FIG. 2 is a detailed system diagram of an adjacent distance measuring circuit shown in FIG. 1, and FIG.
(a) and (b) are wire diagrams for explaining disconnection detection, FIG. 4 is an explanatory diagram for determining the distance between adjacent wires and the center line of the present invention, and FIG. 5 is an inspection of the present invention. FIG. 6 is an explanatory diagram for determining the position, and FIG. 6 is an explanatory diagram for obtaining the distance between adjacent wires when the wire curves and crosses the center line.

In FIG. 1, 5 is a stage on which an IC, which is an object 6 to be inspected as shown in FIG. 7, is placed. The object 6 to be inspected is illuminated by the illumination device 7 when the image is taken by the image pickup device 8, and the object to be inspected is moved to the image pickup position and imaged. An image pickup pattern obtained by picking up the object 6 to be inspected is given to an analog-digital conversion circuit (hereinafter referred to as A / D) 10 through an image pickup device drive circuit 9 so that the image pickup pattern is digitized and a digital image is stored in an image memory 11 in the next stage. Stored in the form. The contents of the image memory 11 are read out by the contour detection circuit 13,
Then, the contour start points S ₁ and S ₂ and the contour end points E ₁ and E _{2 of the} object 6 to be inspected by the inspection start point / end point designating circuit 12.
Be instructed. This is shown in FIG. For example, by instructing the wires 3a and 3b which are linear objects, the contour is detected from the data from the image memory 11. As described above, this contour detection method is performed, for example, according to the contour detection procedure shown in FIG. After the wire contour is detected, the contour data is applied to the adjacent distance measuring circuit 14 of the present invention to measure the adjacent distance between the adjacent wires. The adjoining distance measuring circuit 14 will be described in detail with reference to FIG.

As shown in FIG. 2, the adjacency distance measuring circuit 14 of the present invention includes a center line arithmetic circuit 14a, an inter-adjacent distance arithmetic circuit 14b, an inspection position arithmetic circuit 14c, a disconnection detecting circuit 14d, and a memory 1.
4e.

The contour data from the contour detection circuit 13 is the center line arithmetic circuit 1
4a and a disconnection detection circuit, and a center line arithmetic circuit 14a
Is given to the adjacent distance calculation circuit 14b, and the output of the adjacent distance calculation circuit 14b is the inspection position calculation circuit 14c.
Is supplied to the memory 14e, and the output of the inspection position calculation circuit 14c is supplied to the memory 14e. The output of the disconnection detection circuit 14d as well as the memory 14e is output to the abnormality detection circuit 15. The wire breakage detection circuit 14d detects the presence or absence of wire breakage based on the left, right, or upper and lower contours detected by the contour detection circuit 13 (the positions of points on the contour are obtained as, for example, X and Y coordinates). . Wire is third
In the normal state as shown in FIG. 9A, the contours on the left and right sides shown in FIGS. 9A and 9B from the examination start point S ₁ to the examination end point E ₁ . Since the detection patterns respectively move on the actual left and right contours, the X coordinate xl at an arbitrary position on the left contour obtained by the contour detection.
₁ is the X coordinate xr on the right contour in the same Y coordinate
Always to the left of ₁ . However, the wire is shown in Fig. 3 (b).
When the line is broken as shown in Fig. 2, the left and right contour detection patterns both make U-turns at the ends of the broken portion and move on the opposite contours. The X coordinate xl ₁ of the obtained left contour comes to the right of the X coordinate xr ₁ of the right contour. Therefore, since the X coordinate is laterally reversed in this way, the disconnection state can be detected. In the case of the upper and lower contours, the disconnection state can be detected by checking whether the Y coordinate is reversed upside down.

Further, the wire, that is, the distance between the adjacent linear objects has conventionally been measured only in the X and Y axis directions, but in the present invention, as described above, the center line arithmetic circuit 14a, the adjacent distance arithmetic circuit 14b, the inspection position. As shown in FIG. 4, the center line arithmetic circuit 14a includes an arithmetic circuit 14c and a memory 14e, and the center line arithmetic circuit 14a includes inspection start points S ₁ and S ₂ of adjacent wires 3a and 3b and center points S ₁ and ₂ of inspection end points E ₁ and E ₂ . Ask for E. That is, S, E
A straight line connecting the two is used as the center line CL, and this value is output to the adjacent distance calculation circuit 14b in the next stage. Adjacent distance calculation circuit 1
4b measures the distance d ₁ + d ₂ = d of the perpendicular 16 drawn perpendicularly to the center line CL. Wires 3a adjacent to each other,
The positions of 3b are midpoints P ₁ and P ₂ of the left and right contours of the wire.

The distance between adjacent wires d = d ₁ + d ₂ shown in FIG. 4 is d ₁ ,
Since both d ₂ are similarly obtained, the procedure for obtaining the distance d ₁ will be described. The distance _{d 1} between the intersection P which is perpendicular to the wire center point _{P 1} and the center line CL is determined distances _xa 1, ya ₁ in the x-direction and y-direction center line CL from the wire center point _{P 1} [Delta] P ₁ P ₃ P ₄ The area of Because The distance d _{1 of the} perpendicular line 16 standing on P ₁ from the center line CL is obtained. Similarly the distance _{d 2} of a perpendicular 16 stood to _{P 2} from the center line CL The total distance between adjacent wires is calculated from d = d ₁ + d ₂ , Required by.

Further, as shown in FIG. 6, the wires 3a, which are adjacent to each other,
When one of 3b curves inward from the center line CL, it is clear that it can be obtained by d = d ₁ -d ₂ (4) .

The distances d ₁ and d ₂ described above are stored in the temporary memory 14b. Further, the length measurement result d _{1 and the} like are given to the inspection position calculation circuit 14C to obtain the distance between the SPs of the center line CL as shown in FIG. The position of the SP to be detected is such that the line xb ₁ drawn in the x direction from the inspection start point and the perpendicular line drawn in the y direction from P ₁ are orthogonal to the line xb ₁ and the distance to the point intersecting the center line CL. calculated from yb ₁ When The sum is calculated. Ie Becomes The value of ▲ ▼ is also stored in the memory 14e.
The d at the position indicated by ▼ can be output from the memory 14e.

In the abnormality detection circuit 15, if the value of d shown in the equation (3) is d> α (where α is a predetermined level), it is determined to be normal, and if d ≦ α, it is determined to be an approaching or contacting state. It is done like this.

(8) Effect of the Invention Since the present invention is configured as described above, it is possible to accurately and automatically measure the distance between adjacent parts of a linear object radially wire-bonded from an IC chip to an IC package, particularly at a corner part. It has characteristics.

[Brief description of drawings]

FIG. 1 is a system diagram of the linear object inspection apparatus of the present invention, FIG. 2 is a system diagram showing further details of the adjacent distance measuring circuit of FIG. 1, and FIGS. 3 (a) and 3 (b) show disconnection detection. FIG. 4 is a wire diagram for explaining, FIG. 4 is an explanatory diagram for determining a distance between adjacent wires and a center line of the present invention, and FIG. 5 is an explanatory diagram for determining a detection position of the present invention. FIG. 6 is an explanatory diagram for obtaining the distance between adjacent wires when the wires are curved and cross the center line, and FIG. 7 shows the relationship between the conventional IC chip and the package after wire bonding. Perspective view,
FIG. 8 is a plan view of the wire shown in FIG. 7, and FIGS. 9 (a) and 9 (b).
FIG. 10 is an explanatory view showing a conventional left and right contour detecting procedure, and FIG. 10 is a partially cut enlarged plan view for explaining a conventional method for detecting an adjacent linear object at a corner portion of an IC chip and an IC package lead. 5 ... Stage, 6 ... Inspected object, 8 ... Imaging device,
10 ... A / D conversion circuit, 11 ... Image memory, 12 ...
… Inspection start point end point instruction circuit, 13 …… Contour detection circuit,
14 ... Adjacent distance measurement circuit, 14a ... Center line arithmetic circuit, 14b ... Adjacent distance arithmetic circuit, 14c ... Inspection position arithmetic circuit, 14d ... Disconnection detection circuit, 14e ... Memory, 15 ... Abnormality detection circuit.

Claims (1)

[Claims] 1. An image pickup means for picking up two adjacent linear objects as an object to be inspected, and an analog / digital conversion means for converting an analog picked-up image obtained by the image pickup means into a digital image. An image memory for storing a digital image, a distance measuring means for measuring a distance between the two linear objects based on the digital image stored in the image memory, and the linear object based on a measurement result of the distance measuring means. In the linear object inspection device, the distance measuring means includes a center between inspection start points of the two linear objects in the digital image and an inspection end point. It has a center line calculating means for obtaining a center line which is a straight line connecting the center and a distance calculating means for obtaining a distance between the two linear objects perpendicularly to the center line. A linear object inspection device.