JPH0521569A - Image input equipment - Google Patents

Abstract

PURPOSE:To input a high resolution image, and inspect the shape of a wire or the like with high precision, regarding an image input equipment which is used for the visual inspection of a bonding wire or the like in a semiconductor device or the like. CONSTITUTION:The image picking up line region 3b in the plane radiation direction of an IC chip 3 as an inspection object is formed with an image- forming lens 6, by changing the optical path with a reflecting mirror 5, and picked up by using a line sensor 2. A ring type region is formed by revolving the line sensor 2, the image-forming lens 6, and the reflecting mirror 5 around a revolving axis 9 as the center, with a revolution driving means 8, and the range of an image input region 3a is picked up.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image input device used for visual inspection of bonding wires and the like in semiconductor devices and the like.

In recent years, a large amount of semiconductor devices such as ICs and LSIs have been used in a wide range, and there is a demand for automated visual inspection of bonding wires in the manufacturing process to inspect the wire shape. Therefore, it is necessary to input a wide variety of images with different chip sizes and the like with high resolution while the bonding wire density is high.

[0003]

2. Description of the Related Art FIG. 5 shows a diagram for explaining an inspection target. In FIG. 5A, a chip 51 is mounted on a die pad attached to the central portion of the lead frame 50, and bonding pads 52 are arranged on the chip 51. Then, a wire 54 is used to perform bonding between the bonding pad 52 and the inner lead 53. In this case, the inspection target is the shape of the bonding ball on the bonding pad 52 and the inner lead 53, and the trajectory of the wire 54.

Therefore, the corresponding inspection area is shown in FIG.
As shown in (D) to (D), the wires 54 and the like are located in the shaded areas 56a to 56c in the areas 55a to 55c having different sizes depending on the type of IC.

In the wire shape inspection in this case, the inspection objects of the hatched portions 56a to 56c are input collectively or dividedly and images are input. The image input collectively is, for example, to scan the line sensor vertically or horizontally to obtain an image. Also, the image input that is performed by dividing is
The hatched portions 56a to 56c to be inspected are performed in a predetermined number of divided areas, and the image processing is performed comprehensively.

[0006]

However, in the case of collectively inputting an image, there is a problem that the resolution of the input image is not sufficient and the inspection cannot be performed with high accuracy. In addition, when inputting images in a divided manner, multiple imaging devices are required,
Alternatively, there is a problem that it is necessary to move one imaging device to an arbitrary position.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide an image input apparatus for inputting a high-resolution image and inspecting the shape of a wire or the like with high accuracy.

[0008]

FIG. 1 is a diagram for explaining the principle of the present invention. In FIG. 1, in the image input device 1, 2 is a line sensor, which is arranged vertically (or horizontally) with the inspection object 3 and takes an image of the imaging line region 3b in the image input region 3a in the plane radial direction. Reference numeral 4 denotes an optical path changing means, which is composed of a reflection mirror 5 and an imaging lens 6, and changes the optical path of the reflected light 7a from the inspection object 3 by the irradiation light 7 to form an image. 8 is a rotation driving means,
The optical path changing means 4 and the line sensor 2 are rotationally moved in parallel with the plane of the inspection object 3 about the rotation axis 9.

Further, 10 is an image pickup area changing means for moving the image pickup line area 3b incident on the line sensor 2 relatively on the light receiving surface of the line sensor 2 in the plane radiation direction of the inspection object 3. Is.

[0010]

As shown in FIG. 1, the image pickup line region 3b of the inspection object 3 in the plane radiation direction is changed by the reflection mirror 5, the image is formed by the image forming lens 6, and the line sensor 2 takes an image. Then, the rotation driving means 8 rotates the line sensor 2, the imaging lens 6 and the reflection mirror 5 about the rotation axis 9. That is, the line sensor 2 forms an annular area by rotating and scanning the imaging line area 3b and images the area of the image input area 3a.

Further, the image pickup area changing means 10 moves the line sensor 2 and the imaging lens 6 in the vertical direction, for example, to move the image pickup line area of the inspection object 3 in the radial direction (planar radial direction). Is.

As a result, it becomes possible to input an image into the line sensor 2 only in a necessary area. Further, the image input width of the imaging range (image input area) 3a can be narrowed according to the width of the line sensor 2, and high-resolution image input can be performed.

[0013]

FIG. 2 shows a block diagram of an embodiment of the present invention.
In FIG. 2, the image input device 1 is used for, for example, a wire bonding inspection (see FIG. 5), and the rotary stage 1 that constitutes a rotary drive means 8 that rotates around a rotary shaft 9 is used.
The reflection mirror 5 and the X stage 16 that constitutes the imaging region changing unit 10 are attached to the display unit 5. A line sensor 2 such as a CCD (charge coupled device) is provided in the vertical direction on the X stage 16, and the line sensor 2 and the reflection mirror 5 are provided.
And the imaging lens 6 is provided between and. The reflection mirror 5 and the imaging lens 6 constitute the optical path changing means 4.

An epi-illumination device 17 is located below the rotary stage 15, and irradiates the irradiation light 7 onto the IC chip (see FIG. 5A) 3 which is an inspection object placed on the frame feeder 18. .

On the other hand, the image signal from the line sensor 2 is
Processing is performed by the image input circuit unit 19, the image memory unit 20, the polar coordinate-rectangular coordinate conversion unit 21, the window image generation unit 22, the image processing memory unit 23, and the bonding wire inspection unit 24.

To explain the operation, first, the IC chip 3 is conveyed by the frame feeder 18, and the epi-illumination device 1 is installed.
Irradiation light 7 is emitted from 7. The reflected mirror 7 changes the optical path of the reflected light 7a from the IC chip 3 (bonding wire or bonding ball) in parallel with the plane of the IC chip 3. The reflected light 7a whose optical path has been changed is imaged on the light receiving surface of the line sensor 2 by the imaging lens 6. Then, by rotating the rotary stage 15 about the rotation axis 9, the line sensor 2, the imaging lens 6 and the reflection mirror 5 are rotated and moved in parallel with the plane of the IC chip 3 with the rotation axis 9 aligned. . That is, the line sensor 2 rotationally scans the annular area (image input area, see FIG. 3) 3a of the IC chip 3.

FIG. 3 is a diagram for explaining the image input area of the present invention. Line sensor 2 in FIG.
Is rotated and scanned at the center C so that an image is input without a gap in the outermost peripheral portion of the annular region (radius R). Therefore, in the range of the width W of the line sensor 2 from the distance C from the center C to the input width L of the line sensor 2 (imaging line area 3b),
The areas to be imaged are overlapped from the outer peripheral side toward the inner peripheral side, and the resolution of the image becomes higher toward the inner side.

Referring back to FIG. 2, the X stage 6 moves the line sensor 2 and the imaging lens 6 in a direction perpendicular to the plane of the IC chip 3. As a result, the imaging line area 3b (FIG. 3) in the radial direction of the IC chip 3 moves. That is, as shown in FIG. 3, the distance D from the center C of the annular image input area 3a can be adjusted, and I
It is possible to deal with the case where the inspection area differs depending on the size of the C chip 3.

As described above, the image received by the line sensor 2 is converted as image data by the image input circuit section 19 into a digital signal of 256 gradations and stored in the image memory section 20. When the image input is completed, the polar coordinate-orthogonal coordinate conversion unit 21 generates an image in a rectangular coordinate system from the original image in polar coordinates. Therefore, the window image generation unit 22 takes out an image of a desired area and sequentially stores it in the image processing memory unit 23. Then, the bonding wire inspection unit 24 inspects a wire breakage or a contact with another wire by image tracking or the like, and also inspects the shape such as the size or distortion of the bonding ball.

Next, FIG. 4 shows a block diagram of another embodiment of the present invention. The image input device 1 of FIG.
The line sensor 2 is provided horizontally on the plane of the IC chip 3.
A half mirror 25 with an imaging lens 6 interposed below the half mirror 25.
Is located. And the half mirror 25
And the reflection mirror 5 are arranged side by side, and the other parts are the same as those in FIG. In this case, the rotary stage 1
5, the line sensor 2, the imaging lens 6, the half mirror 25, and the reflection mirror 5 are rotationally moved in parallel with the plane of the IC chip 3 with the rotation axis 9 aligned (not necessarily aligned). is there.

As described above, by constructing the image pickup system corresponding to the polar coordinate system, a region having a small radius (IC chip 3
In the center direction area of the IC chip 3), where the radius is large (IC chip 3
(Outer direction area) of the image is obtained. That is, as shown in FIG. 5, in the area where the wires of the IC are bonded, the bonding balls are inward,
The wire is outside it. Therefore, in the shape inspection of the bonding ball, a higher precision inspection than the shape inspection of the wire is required, which can meet the demand. Further, since the imaging region can be changed in the radial direction, it is possible to correspond to different sizes of the inspection target.

[0022]

As described above, according to the present invention, the imaging line area of the inspection object in the plane radiation direction is changed by the optical path changing means to form an image, and the line sensor takes an image to rotate the moving area in the annular area. By sequentially capturing images, it is possible to perform high-resolution image input and inspect the shape of a wire or the like with high accuracy.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

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

FIG. 3 is a diagram for explaining an image input area of the present invention.

FIG. 4 is a configuration diagram of another embodiment of the present invention.

FIG. 5 is a diagram for explaining an inspection target.

[Explanation of symbols]

1 Image input device 2 line sensor 3 Inspection target 3b Imaging line area 4 Optical path changing means 5 reflection mirror 6 Imaging lens 7 Irradiation light 7a reflected light 8 rotation drive means 10 Imaging area changing means

Claims (3)

[Claims] 1. An image input device for irradiating a light (7) to an inspection target (3) to input an image, wherein reflected light ((1) from the inspection target (3) by the irradiated light (7) ( Optical path changing means (4) for changing the optical path of 7a) to form an image, a line sensor (2) for imaging the imaging line area (3b) of the inspection object (3) in the plane radiation direction, and the optical path changing An image input device comprising: a means (4) and a line sensor (2) for rotating and moving the means (4) in parallel with the plane of the inspection object (3). 2. The image pickup line region (3b) incident on the line sensor (2) is relatively moved in a plane radiation direction of the inspection object (3) on a light receiving surface of the line sensor (2). The image input apparatus according to claim 1, further comprising an image pickup area changing unit (10). 3. The image input device according to claim 1, wherein the line sensor (2) is arranged vertically or horizontally on the plane of the inspection object (3).