JP2842486B2 - Transparent mold IC inspection equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent molded IC inspection apparatus for inspecting the appearance of an IC having a transparent mold.

[0002]

2. Description of the Related Art A transparent molded IC is an IC in which a package is made of a transparent resin so that an optical sensor mounted on a chip surface of the IC can receive external light.
It is. Therefore, the chip surface and the lead frame can be observed through the mold from the appearance. Inspection of a conventional transparent mold IC has been performed by a full-time inspector who inspects all defects on the surface and inside of the mold visually using a microscope.

[0003]

SUMMARY OF THE INVENTION Conventional transparent mold I
Since the inspection of C was performed as described above, there were problems such as an inspection error such as an oversight in the visual inspection, variation in the inspection standard, unstable quality, and a limitation in human processing ability. SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a transparent mold IC inspection apparatus that can automate the appearance inspection of a transparent mold IC.

[0004]

A transparent mold IC inspection apparatus according to the present invention uses oblique illumination, falling illumination, and transmission illumination as illumination light when inspecting the appearance of a transparent mold IC, and switches between them. In this way, by processing a plurality of images obtained from the camera, the appearance of the transparent mold IC is inspected.

[0005]

According to the transparent mold IC inspection apparatus of the present invention, when a transparent mold IC is illuminated using oblique illumination, the reflection is performed only on one side when the chip surface such as a light receiving element portion is flat. The image is dark without light. On the other hand, where the chip surface is rough, such as a pattern portion, light is irregularly reflected, so that a bright image is taken by the camera. Since the pattern shape of the IC chip is stable, the chip can be positioned by using this illumination if the flat or rough portion of the chip is known from the design data in advance.

[0006] The falling illumination is an illumination method similar to a conventional inspection method using a microscope, and an image close to visual observation can be taken. Therefore, if an automatic inspection is performed by performing image processing from this image, there is an advantage that the standard of the conventional visual inspection can be used, and that it is easy to cope with the visual inspection.

When light is illuminated using transmission illumination, the light passes through the transparent mold, but the wires, lead frames, etc. in the mold do not pass light and form shadows. This image is suitable for shape inspection because the contrast is clearer than when the image was captured using falling illumination.

Further, by inspecting while switching the field of view and the magnification, it is possible to perform a wide-area inspection and a partial inspection, and to inspect a portion having a weak inspection standard such as the appearance of the entire chip surface at a low magnification at a time. Inspection according to the inspection standard can be performed, for example, by processing, or processing a portion having a strict inspection standard such as inspection of a light receiving element portion at a high magnification.

[0009]

【Example】

Embodiment 1 FIG. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a transparent mold IC to be inspected, and reference numeral 2 denotes a sample stage on which the transparent mold IC 1 is mounted and has a through hole 2a. Reference numeral 3 denotes a microscope for observing the transparent mold IC 1, reference numeral 4 denotes an objective lens of the microscope 3, and reference numeral 5 denotes a camera for capturing an image observed by the microscope 3, and a television camera 5 is used here. Reference numeral 6 denotes an oblique illumination unit that illuminates the transparent mold IC 1 from obliquely above, 7 denotes an oblique illumination unit that illuminates the transparent mold IC 1 from directly above through the objective lens 4 of the microscope 3, and 8 denotes a transparent mold IC 1 that passes through the sample table 2. Hole 2a
It is a transmitted illumination unit that illuminates from directly below through the light.

Reference numeral 9 denotes an image memory for storing an image signal from the television camera 5, reference numeral 10 denotes an image processing section for processing the image signal read from the image memory 9, and reference numeral 11 denotes whether the transparent mold IC 1 is good or bad based on the processed image signal. Judgment unit for judgment, 1
Reference numeral 2 denotes a determination result signal, and 13 denotes an illumination switching unit for selectively switching the lighting of the oblique illumination unit 6, the falling illumination unit 7, and the transmission illumination unit 8, and is controlled by signals from the image memory 10 and the image processing unit 11. Is done. The oblique illumination unit 6, the falling illumination unit 7, and the transmission illumination unit 8 constitute an illumination unit.

Next, the operation will be described. In the inspection apparatus configured as described above, the inspection procedure is as shown in the flowchart of FIG. In the first positioning step S1, first, the oblique illumination 6 is turned on in step ST1 to capture an image with the camera 1, and the image is taken into the image memory 9 in step ST2. As shown in FIG. 3, the image of the chip in the transparent mold IC 1 is dark in a place 14 where the chip surface is flat and bright on a surface 15 where the chip is not flat. Are compared, and in step ST3, the chips are positioned such that they match. In addition, in FIG. 3, 16 is a wire, 17
Indicates a lead frame.

In the foreign matter inspection step S2, the illumination switching section 13 switches from the oblique illumination section 6 to the falling illumination section 7 in step ST4. As a result, an image similar to that when the inspection is performed visually is obtained as shown in FIG. After fetching this image into the image memory 9 in step ST5, the image processing unit 10 and the determination unit 11 inspect the surface for scratches and the inside of the mold in step ST6.

In the wire shape inspection step S3, step S
At T7, the illumination switching unit 13 switches the falling illumination unit 7 to the transmission illumination unit 8
Switch to. As a result, the TV camera 5
6. The shape of the lead frame 17 can be imaged with good contrast as shown in FIG. The image is taken into the image memory 9 in step ST8. From this image, step ST9
Then, the image processing unit 10 and the determination unit 11 inspect the wire shape.

In the final determination step S4, the determination section 11 outputs a final determination result signal 12 in step ST10 from the inspection results of the respective steps S1 to S3. For example, mixing of different ICs is performed in step S1, foreign matter and voids in the mold are performed in step S2, and bending of the wire is performed in step S3.
Is recognized at each stage and is regarded as a defective product.

Embodiment 2 FIG. In the first embodiment, by attaching a zoom lens in place of the objective lens 4 and attaching the microscope 3 to a moving table, it becomes possible to perform inspection while switching the field of view and the magnification.

[0016]

As described above, according to the present invention, according to the inspection items of the transparent mold IC, the transparent mold I is switched while switching any of the oblique illumination, the falling illumination, and the transmission illumination.
C, the transparent mold IC is configured to be imaged, so that it is possible to irradiate the transparent mold IC with appropriate illumination according to the inspection item. As a result, the inspection accuracy of the transparent mold IC is improved. And the reliability of the transparent mold IC is improved. Also, oblique lighting
The flat part of the semiconductor chip is detected as a dark part based on the image signal at the time, and the position of the semiconductor chip is detected, so that the flat part of the semiconductor chip can be detected with high contrast. As a result, there is an effect that the inspection accuracy of the transparent mold IC is improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a transparent mold IC inspection apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart showing an inspection procedure of the inspection apparatus.

FIG. 3 is an image of a transparent mold IC when an oblique illumination unit of the inspection device is turned on.

FIG. 4 is an image of a transparent mold IC when a falling illumination unit of the inspection apparatus is turned on.

FIG. 5 is an image of a transparent mold IC when a transmission illumination unit of the inspection device is turned on.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transparent mold IC 5 TV camera 9 Image memory 11 Judgment part 13 Lighting switching part

Continuation of the front page (56) References JP-A-3-99251 (JP, A) JP-A-3-209154 (JP, A) JP-A-2-82141 (JP, A) JP-A-2-81449 (JP) JP-A-63-29206 (JP, A) JP-A-56-155802 (JP, A) JP-A-58-58449 (JP, A) JP-A-59-216002 (JP, A) 62-299705 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) G01N 21/84, 21/88 G01B 11/24

Claims (1)

(57) [Claims] 1. An illumination means for performing oblique illumination, falling illumination, or transmission illumination on a transparent mold IC;
A lighting switching means for switching the irradiation method, in the illumination means
Image of the transparent mold IC irradiated
Cameras that output signals and images output from the cameras
Semiconductor chip based on the image signal during oblique illumination
The flat portion of the-up is detected as a dark portion, and an image processing means for detecting the position of the semiconductor chip, output from the camera
And a judging means for judging a defect of the transparent mold IC based on the image signal.