JP2000180136A - Device and method for inspecting semiconductor package - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the device and method for inspecting a semiconductor package, such as a photodetector, which is sealed with a transparent resin. SOLUTION: The luminous flux of a light source needed for the inspection is converted into slit light suitable for the inspection, the semiconductor package 13 fixed to a movable table 14 is irradiated with the above slit light, and image of irregularly reflected light at a defect place in the semiconductor package 13 is picked up by an image pickup means. Here, the image pickup operation is carried out by stages by moving the table 14 stepwise. Images picked up in the respective stages are compared with prepared conforming-article imaged data corresponding to the respective stages to judge whether or not the semiconductor package 13 is normal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection apparatus and an inspection method for a semiconductor package for detecting an abnormality in the appearance of a semiconductor package, and more particularly to an inspection apparatus and an inspection method for a semiconductor package for performing an appearance inspection by utilizing light reflection. .

[0002]

2. Description of the Related Art As one of inspection methods for detecting a defective appearance of a semiconductor package, there is a surface analysis using light. Generally, diffuse light illumination is applied from the top of the semiconductor package, or side illumination is applied from the lateral direction,
A method of measuring the reflected light is used. Usually, these methods are used for surface appearance inspection of a semiconductor package sealed with a black non-transparent resin.

[0003]

However, when this method is applied to select the appearance of a semiconductor package such as a photodetector or the like sealed with a transparent resin, there are the following problems.

One is sealing with a transparent resin,
Even if diffuse light illumination is applied from the top of the semiconductor package,
Light is not sufficiently reflected on the surface of the transparent semiconductor package, and it is difficult to detect the surface state.

When a transparent resin is observed from the outside, an image behind the transparent resin can be observed from the resin surface because the resin is transparent. In this case, if the conventional method of irradiating diffused light illumination from the top of the semiconductor package or the method of irradiating side illumination from the lateral direction is used, the subtle changes in light detected by reflection are observed through the transparent resin. Since it overlaps with the image behind, it is difficult to detect the reflected light itself required for detecting a defective appearance.

Further, when the semiconductor package is a photodetector, a transparent sealing resin is used, and it is necessary to detect not only the appearance defect on the surface of the sealing resin but also the appearance defect inside the sealing resin. However, in the conventional method of irradiating diffused light illumination from above the semiconductor package or irradiating side illumination from the lateral direction, the state inside the sealing resin cannot be locally detected.

In addition, in the conventional method, since illumination for inspection is applied to the entire semiconductor package, not only the appearance defect inside the semiconductor package but also dust on the upper surface of the semiconductor package is disturbed as reflected light. Will be detected. Generally, disturbance of reflected light due to three-dimensional dust is larger than disturbance of reflected light due to poor appearance inside the semiconductor package. Therefore, it is difficult to distinguish defective appearance inside the semiconductor package that one really wants to detect.

The present invention has been made in view of the above points, and an object of the present invention is to provide a transparent substance inspection apparatus and an inspection method capable of efficiently and locally detecting appearance defects of a semiconductor package sealed with a transparent resin. Aim.

[0009]

According to the present invention, there is provided an inspection apparatus for a semiconductor package having a transparent portion, comprising: a light converting means for converting light from a light source into slit light; A fixed and movable table, imaging means for imaging reflected light obtained by applying the slit light to the semiconductor package, and comparing an image obtained from the imaging means with a non-defective image prepared in advance,
An image inspection means for judging the quality of the semiconductor package is provided.

[0010] The light converting means converts a light beam of a light source required for inspection into slit light suitable for inspection. The slit light is applied to the semiconductor package, and the reflected light is imaged by an imaging unit. The imaging here is performed at each stage by moving the table stepwise. The image taken at each stage is identified by the determination means at each stage, and the quality of the semiconductor package is determined.

Since the slit light is used as the light source for measurement, only the boundary surface between bubbles and voids inside the semiconductor package is emphasized and detection is easy. Further, since the reflection of light is identified for each movement stage of the semiconductor package, the situation inside the semiconductor package can be locally and three-dimensionally detected.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. First, the configuration of the semiconductor package inspection device of the present embodiment will be described.

FIG. 1 is a structural view of the inspection apparatus of the present invention. A movable table 14 is provided below the inspection device 10.
At the time of inspection, the semiconductor package 13 to be inspected is fixed at a predetermined position on the table 14 by vacuum suction or the like. A table position sensor 19 is attached to the table 14. The table position sensor 19 is electrically connected to an image processing system 17 described later via a cable 20.

On the side surface of the inspection apparatus 10, there is provided a fiber illumination light emitting section 11 having a fiber tip processed so that the cross section of the light beam becomes rectangular, and the fiber illumination light emitting section 11 is halogen-illuminated via a cable 11a. Power supply 1
1b. In addition, fiber illumination light emitting section 1
Between the table 1 and the table 14, the illumination slit type variable aperture 12 is provided.

At the top of the inspection device 10, a CCD camera 1
The CCD camera 15 is provided with an optical lens 15a whose focus can be freely adjusted.

The CCD camera 15 is electrically connected to an image processing system 17 via a cable 16. The image processing system 17 includes an image processing means 17a for processing image data sent from the CCD camera 15, a non-defective image memory 17b in which non-defective image models are recorded,
An inspection result recording memory 17c for recording the result after the inspection,
Table position control means 1 for processing table position information
7d.

The fiber illumination light emitting section 1
1. The illumination slit-type variable aperture 12, the semiconductor package 13, the table 14, the CCD camera 15, and the optical lens 15a are covered with an outside light hood 18.

FIG. 2 is a detailed view of the slit-type variable diaphragm 12 for illumination. The illumination slit-type variable diaphragm 12 includes an opaque upper plate 12c, a lower plate 12d, and a gap adjusting screw 12.
a, 12b, and the gap adjusting screws 12a, 12b
By rotating the upper plate 12c and the lower plate 12
The position of d can be adjusted. A central opening 1 formed when the upper plate 12c and the lower plate 12d are combined is provided at the center of the illumination slit-type variable diaphragm 12.
2e, rotate the gap adjusting screws 12a, 12b,
The slit width 12f of the central opening 12e can be changed by adjusting the positions of the upper plate 12c and the lower plate 12d.

Next, the overall operation will be described with reference to FIGS. The fiber illumination light-emitting unit 11 emits light when supplied with power from a halogen irradiation power supply 11b via a cable 11a. Adjustment of the amount of light emitted by the fiber illumination light emitting section 11 is performed by changing the voltage of the halogen irradiation power supply 11b. The light emitted from the fiber illumination light-emitting unit 11 reaches the slit-type variable diaphragm 12 for illumination, a part of the light that has passed passes through the central opening 12e, and a part of the light reaches the upper plate 12c.
Or it is shut off by the lower plate 12d. For this reason, the gap adjusting screws 12a and 12b are rotated and the central opening 12e is rotated.
By changing the slit width 12f of the central opening 1
The width of the light beam passing through 2e can be freely adjusted.
Hereinafter, the light that has passed through the central opening 12e is referred to as slit light.

Thereafter, the slit light is applied to the semiconductor package 1.
3 and is irradiated from the side of the semiconductor package 13. The table 14 to which the semiconductor package 13 is fixed moves up and down and the semiconductor package 1
3 can be rotated stepwise, and by moving the table 14, the semiconductor package 13 can be rotated.
Can be changed. By changing the position of the semiconductor package 13, the semiconductor package 1 is changed.
3, the slit light incident position can be changed.
The position of the table 14 is detected by the table position sensor 19, and the position information is sent to the image processing system 17 via the cable 20.

When the slit light reaches the side surface of the semiconductor package 13, a part of the light is reflected on the surface of the semiconductor package 13, and a part of the light is reflected on the surface of the semiconductor package 13 or on the boundary surface of bubbles, cracks or voids. Diffuse reflection occurs at poor appearance. A part of the irregularly reflected light enters the CCD camera 15 via the optical lens 15a. The fiber illumination light emitting section 11, the illumination slit type variable aperture 12, the semiconductor package 13, the table 14, the CCD camera 15, and the optical lens 15a are covered with an external light shielding hood 18, and the fiber illumination light emitting section This prevents external light other than the inspection light emitted from 11 from entering the inspection path.

The irregularly reflected light that has entered the CCD camera is captured as inspection image data and sent to the image processing system 17 via the cable 16. The sent inspection data is processed by the image processing means as follows.

The non-defective image memory 17b of the image processing system 17 stores non-defective image data corresponding to the position information of the table 14 on a one-to-one basis. The table position control means 17d retrieves non-defective image data corresponding to the actually transmitted position information from the non-defective image memory 17b and sends it to the image processing means 17a. Image processing means 1
7a extracts the difference between the sent good image data and inspection image data. The extracted comparison result and inspection image data are recorded in the inspection result storage memory 17c together with the position information of the table 14.

Then, the same flow as described above is applied to the table 14.
Is performed for each moving position, and the inspection results are sequentially recorded. Next, the state of the inspection image will be described.

FIG. 3 shows how the semiconductor package 13 is irradiated with slit light. In the semiconductor package, a semiconductor chip 13a is sealed with a transparent resin 13b.

Normally, a part of the slit light 13c applied to the semiconductor package 13 is reflected on the surface of the transparent resin 13b, and a part is reflected on the surface of the semiconductor chip 13a. However, if there is a defective appearance portion 13d such as a crack or a void in the transparent resin 13b, the slit light causes irregular reflection at the defective appearance portion 13d.

When the slit light reflects on a flat surface such as the surface of the transparent resin 13b or the surface of the semiconductor chip 13a, the angle of incidence of the slit light incident on these surfaces (normal to the reflecting surface set at the incident point). Is equal to the reflection angle (the angle formed by the reflected light and the normal to the reflecting surface at the incident point). Therefore, the transparent resin 1
Regarding the slit light reflected on the surface of 3b or the surface of the semiconductor chip 13a, the path of the reflected light is determined if the incident angle is determined. This incident angle can be changed by changing the position of the table 14,
The D camera 15 is installed at a position off the path of all the reflected light corresponding to the range of change of the incident angle.

On the other hand, the irregularly reflected light irregularly reflected at the defective appearance portion 13d travels in various directions depending on the shape of the defective appearance portion 13d, and a part of the irregularly reflected light reaches the CCD camera 15.

Thus, the reflected light on the surface of the transparent resin 13b or the surface of the semiconductor chip 13a does not enter the CCD camera 15, but only a part of the irregularly reflected light enters. Therefore, the CCD camera 15 picks up an image by emphasizing the irregularly reflected light, and can detect a defective appearance of the transparent resin 13 based on the picked up irregularly reflected image.

The irregular reflection is caused not only by the defective portion 13d but also by dust adhering to the surface resin of the transparent resin 13b. However, the irradiating light is slit light whose light beam width is narrowed down, so that diffused reflection due to dust can be suppressed as compared with the case where diffused light is used.

Next, the processing procedure of the image processing system 17 will be described. FIG. 4 is a flowchart illustrating a processing procedure of the image processing system 17. [S1] The table position control means 17d detects the position information of the table 14 sent from the table position sensor 19. [S2] The table position control unit 17d performs step S
The non-defective image data corresponding to the position information of No. 1 is extracted from the non-defective image memory 17b, and the non-defective image data is sent to the image processing means 17a. [S3] The image processing unit 17a compares the inspection image data sent from the CCD camera 15 with the non-defective image data sent from the table position control unit 17d.
Create comparison result data. [S4] The image processing means 17a records the inspection image data sent from the CCD camera 15 and the comparison result data created in step S3 together with the position information detected in step S1 in the inspection result storage memory 17c.

As described above, in the present embodiment, the slit light is irradiated from the side surface of the semiconductor package 13 to enhance the diffuse reflection at the defective appearance portion 13d of the semiconductor package 13 so that the imaging can be performed. It is possible to easily detect the appearance defect of the semiconductor package sealed with the resin.

Further, since the semiconductor package 13 is fixed to the movable table 14 and the inspection can be performed by locally irradiating the slit light having a small luminous flux width while moving the semiconductor package 13, the semiconductor package 13 can be three-dimensionally and locally. Can be inspected.

Further, since the semiconductor package 13 is locally irradiated with slit light having a narrow light flux width,
The influence of irregular reflection caused by dust adhering to the surface of the semiconductor package 13 which hinders the appearance defect detection can be reduced.

In this embodiment, there is only one non-defective image data corresponding to one position on the table 14. However, the depth of focus of the optical lens 15a is reduced, so that the semiconductor package 13
A plurality of non-defective image data may correspond to each section. When the depth of focus of the optical lens 15a is reduced, the displacement of the light receiving efficiency of the CCD camera 15 with respect to the difference in the irregular reflection position in the thickness direction of the semiconductor package 13 can be increased. In this case, the optical lens 1
5a, the semiconductor package 13 is changed.
Since only the irregular reflection at an arbitrary cross section can be taken into the CCD camera 15 while being emphasized, more detailed inspection can be performed for each arbitrary cross section.

In this embodiment, a halogen lamp is used as a light source, but a mercury lamp or the like may be used instead.
Further, in the present embodiment, the semiconductor package is used for the visual inspection, but the present invention may be applied to glass, plastic, liquid, and other transparent materials in general.

[0037]

As described above, in the semiconductor package inspection apparatus of the present invention, the semiconductor package is fixed to a movable table, the semiconductor package is irradiated with slit light, and an image obtained from the reflected light is used. Since the semiconductor package is inspected, an internal defect can be easily found.

In the method of inspecting a semiconductor package according to the present invention, the semiconductor package is inspected by irradiating the slit light while raising and lowering the semiconductor package and using an image obtained from the reflected light. Can be easily found.

[Brief description of the drawings]

FIG. 1 is a structural diagram of an inspection device of the present invention.

FIG. 2 is a detailed view of a slit-type variable diaphragm for illumination.

FIG. 3 is a conceptual diagram illustrating a state in which a semiconductor package is irradiated with slit light.

FIG. 4 is a flowchart illustrating a processing procedure of the image processing system.

[Explanation of symbols]

11: Fiber illumination light emitting unit, 12: Slit type variable aperture for illumination, 13: Semiconductor package, 14: Table,
15: CCD camera, 17: Image processing system

Claims (11)

[Claims] 1. An inspection apparatus for a semiconductor package having a transparent portion, wherein: a light conversion means for converting light from a light source into slit light; a table on which the semiconductor package is fixed and movable; Imaging means for imaging the reflected light applied to the package; and determining means for comparing the image obtained from the imaging means with an image of a non-defective product prepared in advance to determine the quality of the semiconductor package. Semiconductor package inspection device. 2. The inspection apparatus according to claim 1, wherein the semiconductor package is a photodetector. 3. The semiconductor package inspection apparatus according to claim 1, wherein said light source is a halogen lamp. 4. The semiconductor package inspection apparatus according to claim 1, wherein said light converting means is capable of adjusting a width of said slit light. 5. The semiconductor package inspection apparatus according to claim 1, wherein the movable table is rotatable. 6. The semiconductor package inspection apparatus according to claim 1, wherein the movable table is vertically movable. 7. The semiconductor package inspection apparatus according to claim 1, further comprising a position control means for detecting a position of the movable table. 8. A method of inspecting a semiconductor package having a transparent portion, comprising: converting light from a light source into slit light; irradiating the semiconductor package with the slit light; moving the semiconductor package; A method of inspecting a semiconductor package, comprising: taking an image of reflected light applied to a package; and comparing the taken image with an image of a non-defective product prepared in advance to judge the quality of the semiconductor package. 9. The method according to claim 8, wherein the semiconductor package is a photodetector. 10. The semiconductor package inspection method according to claim 8, wherein one image of the non-defective item corresponds to one image of the non-defective item on the movable table. 11. The semiconductor package inspection method according to claim 8, wherein a plurality of non-defective images correspond to one position of the movable table.