JPH0861928A - Illuminating device for appearange inspection - Google Patents

Abstract

PURPOSE: To provide an appearance inspection illuminating device for obtaining optimum reflected light from an object to be inspected. CONSTITUTION: This device is equipped with a cylindrical diffusing section 2 arranged approximately vertically an object to be inspected for example, the inspection surface of a semiconductor device, 10 and a ring type light source 3 laid outside the section 2 and used as an illumination means for radiating light thereto. In this case, light radiated from the light source 3 is diffused by the section 2, and resulting diffused light is emitted from the inner space 21 of the section 2 to the device 10 for obtaining reflected light.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating device for appearance inspection for irradiating an object to be inspected with predetermined light to obtain reflected light.

[0002]

2. Description of the Related Art When performing a visual inspection of a semiconductor device sealed with a mold resin, a semiconductor device to be inspected is irradiated with light and the reflected light is taken in by an optical reading mechanism such as a CCD camera to perform image processing. The quality is judged by applying. When the image based on the reflected light is captured by the optical reading mechanism, it is necessary to irradiate the inspected object with optimum light to obtain reflected light with less noise.

3A and 3B are schematic cross-sectional views for explaining a conventional illuminating device. FIG. 3A is for epi-illumination, and FIG. 3B is for oblique illumination. As shown in FIG. 3A, in the case of epi-illumination, the ring-shaped light source 3 is mainly arranged above the inspection object such as the semiconductor device 10, and the inspection object below the light emitting portion 31 of the ring-shaped light source 3. Irradiate with light.

For example, a semiconductor device, which is an object to be inspected, is irradiated with light directly from the light emitting portion 31 as shown by an arrow in the drawing, or is irradiated with light at an oblique angle as shown by an arrow in the drawing. The reflected light from the package and the lead portion of 10 is obtained. Embossed tape 1 with cover tape 10b
In the case where the semiconductor device 10 is housed in 0a, the angle of this light is adjusted to reduce the noise formed of unnecessary reflected light, and the CCD camera 11 takes in the necessary reflected light.

Further, as shown in FIG. 3 (b), in the case of oblique illumination, a linear oblique light source 30 is mainly arranged diagonally above the object to be inspected such as the semiconductor device 10, and the arrow in the figure is drawn from here. The oblique light is emitted as shown in. In the oblique illumination, unnecessary reflected light is reduced in consideration of the polarization of the cover tape 10b attached to the embossed tape 10a, and necessary reflected light is taken in by the CCD camera 11.

[0006]

However, in the case of inspecting an object to be inspected that reflects a lot of light, such as an inspection of a semiconductor device in an embossed tape to which a cover tape is attached, the above-mentioned illumination device is used to inspect the object to be inspected. It is difficult to obtain the optimum reflected light. That is, in the case of the epi-illumination, most of the light emitted to the surface of the object to be inspected is totally reflected and becomes reflected light with many noise components. For this reason, it becomes difficult to obtain the necessary reflected light, which is a problem when performing a visual inspection by image processing.

Also, with oblique illumination, although total reflection of the emitted light is reduced, halation easily occurs in the captured image when there is something that causes irregular reflection of dust or the like at the irradiation position, and image processing and Visual inspection becomes very difficult. Moreover, in order to avoid such halation, it is necessary to finely adjust the angle of the irradiation light, which leads to complicated inspection work.

Therefore, an object of the present invention is to provide an illuminating device for visual inspection for obtaining optimum reflected light from an object to be inspected.

[0009]

SUMMARY OF THE INVENTION The present invention is a lighting device for visual inspection, which is made to achieve the above object. That is, the illuminating device for appearance inspection according to the present invention is arranged such that the cylindrical diffusing means arranged substantially perpendicular to the inspection surface of the inspection object and the cylindrical diffusing means arranged outside the cylindrical diffusing means emit light. The irradiation means for irradiating is provided, and the light emitted from the irradiation means is diffused through the cylindrical diffusing means, and the diffused light is applied to the object to be inspected from the inside of the cylindrical diffusing means to provide the reflected light. To get it.

[0010]

In the present invention, diffused light is generated in the cylinder by irradiating the cylindrical diffuser with light from the irradiation means arranged outside the cylinder of the cylindrical diffuser. Since the diffused light strikes the inspection object at various angles from the inside of the cylinder, it is possible to obtain reflected light of uniform intensity from the inspection object. Further, even if the inspection object diffusely reflects light, the reflected light is dispersed by the diffused light, so that the reading of the image is not adversely affected.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a visual inspection illumination device according to the present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view illustrating an embodiment of a visual inspection illumination device 1 according to the present invention. That is, in the appearance inspection illuminating device 1 according to the present embodiment, when inspecting the appearance of an object to be inspected that reflects a lot of light, predetermined light is applied to the object to be inspected to obtain the reflected light, and the optical reading mechanism is used. The CCD camera 11 is used to capture an image.

The semiconductor device 10 housed in the embossed tape 10a to which the cover tape 10b is attached will be described below as an object to be inspected that reflects a lot of light. The visual inspection illumination device 1 according to the present embodiment irradiates an object to be inspected, which reflects a lot of light, with the optimum light for image processing. That is, in order to emit such optimum light, the appearance inspection illuminating device 1 and the cylindrical diffusion part 2 arranged substantially perpendicular to the inspection surface (package surface) of the semiconductor device 10 as the inspection object. A ring-shaped light source 3 that is an irradiation unit that is arranged outside the cylindrical diffusion unit 2 and irradiates the cylindrical diffusion unit 2 with light.

The cylindrical diffusing portion 2 is made of, for example, polycarbonate or acetal resin (Delrin: manufactured by DuPont, Duracon: manufactured by Celanese), optical glass (opal glass,
Frosted glass, etc.), polypropylene, polyethylene, vinyl chloride, etc., and is, for example, milky white. The inner surface of the cylinder is satinized to improve the light diffusion effect. Such a cylindrical diffusion part 2 is C
It is arranged along the optical axis of the CD camera 11 and is located inside the cylinder 2
The reflected light from the semiconductor device 10 can reach the CCD camera 11 via 1.

The ring-shaped light source 3 arranged outside the cylindrical diffusing portion 2 has a structure in which a light emitting portion 31 which is an end face of an optical fiber (not shown) is arranged in a ring shape, and a halogen lamp. Light emitted from (not shown) can be emitted from the light emitting portion 31 via this optical fiber.
Further, the ring-shaped light source 3 is provided with a reflection type diffusion plate 32 so that the light emitted from the light emitting portion 31 can be diffused to generate primary diffused light.

In order to perform the appearance inspection of the semiconductor device 10 using the appearance inspection illuminating device 1, first, the cylindrical diffusion portion 2 is arranged so as to be substantially perpendicular to the inspection surface of the semiconductor device 10.
Are arranged, and light is emitted from the light emitting portion 31 of the ring-shaped light source 3 in this state. The light emitted from the light emitting section 31 is diffused by the diffusion plate 32.
Is reflected on the cylindrical diffuser 2 to become a primary diffused light. Further, the primary diffused light becomes a secondary diffused light in the cylinder 21 through the cylindrical diffuser 2, and from there, the semiconductor device 1
It will proceed to the 0 side.

The secondary diffused light strikes the inspection surface of the semiconductor device 10 from the inside 21 of the cylindrical diffuser 2 through the cover tape 10b. The secondary diffused light is diffused in the cylinder 21 in various directions (various angles in the vertical and horizontal directions with respect to the inspection surface), and enters the cover tape 10b at various angles.

At this time, even if disturbance light enters from outside the cylinder of the cylindrical diffusion portion 2, it is diffused inside the cylinder 21. Therefore, the secondary diffused light is totally reflected by the cover tape 10b or diffusely reflected by dust or the like to locally hit the semiconductor device 10 without being strongly reflected light.
Touching the semiconductor device 10 via the cover tape 10b 2
The same applies to the next diffused light, and the reflected light does not become unnecessarily strong even if it strikes a place where diffused reflection is likely to occur, such as the package surface, the edge portion of the lead, or the bent portion.

The reflected light from the inspection surface based on the secondary diffused light that hits the semiconductor device 10 has a uniform light amount and reaches the CCD camera 11 through the cylinder 21. The CCD camera 11 captures the reflected light of this uniform light quantity and transfers it to an image processing device (not shown). CCD camera 11
The reflected light taken in is a high-quality image that is not affected by total reflection by the cover tape 10b or irregular reflection of dust or the like.

As a result, the image processing apparatus (not shown) can perform accurate image processing on the semiconductor device 10 without being affected by ambient light or noise, and can perform accurate quality determination. For example, a product mark attached to the package surface of the semiconductor device 10 or a defect inspection of the package from an image based on reflected light with less noise,
The 1-pin mark and the lead deviation are inspected by image processing. Even if the semiconductor device 10 is housed in the embossed tape 10a to which the cover tape 10b is attached, by irradiating secondary diffused light using the illuminating device 1 for visual inspection according to the present embodiment, an image with less noise can be displayed. Therefore, it becomes possible to perform an accurate visual inspection.

Next, another embodiment of the present invention will be described. FIG. 2 is a plan sectional view for explaining another embodiment. A visual inspection illumination device 1 ′ according to another embodiment includes a cylindrical diffusion portion 2 arranged substantially perpendicular to an inspection surface of a semiconductor device 10 as an inspection object, and a cylindrical diffusion portion 2 on four sides. The side light sources 3'are arranged respectively.

The light emitted from each lateral light source 3'becomes a primary diffused light via the transmissive diffuser plate 32 'and strikes the cylindrical diffuser 2. Further, the primary diffused light becomes a secondary diffused light in the cylinder 21 through the cylindrical diffusing portion 2 and strikes the semiconductor device 10 as the inspection object through the cover tape 10b (see FIG. 1). Then, the reflected light based on the secondary diffused light is captured by the CCD camera 11 shown in FIG. As a result, an image with less noise can be obtained as in the previous embodiment.

In the visual inspection illumination device 1'in another example, by moving the positions of the side light sources 3'arranged in four directions, it becomes possible to deal with the cylindrical diffusing portions 2 of various sizes. That is, the cylindrical diffusion part 2 is replaced according to the size of the semiconductor device 10 as the inspection object, and the position of the lateral light source 3'is adjusted accordingly. As a result, even if the size of the cylindrical diffusion portion 2 is different, it is possible to always apply uniform light.

Even if the cylindrical diffusion portion 2 is not circular (for example, elliptical), it can be dealt with by moving the position of each side light source 3 '. That is, even if the inspection object has a rectangular shape or a long shape, the optimum secondary diffused light can be given. In particular, when inspecting a long object to be inspected, not only the four side light sources 3 ′ are provided, but also a plurality of side light sources 3 ′ are provided along the longitudinal direction of the inspected object. A uniform secondary diffused light can be given to the object.

In any of the embodiments, the light emitted from the ring-shaped light source 3 or the side light source 3'is diffused by the diffuser plates 32,3.
Although the primary diffused light is diffused through 2'to irradiate the cylindrical diffusing section 2, it is not necessary to use the diffusion plates 32, 32 'if uniform light can be radiated to the cylindrical diffusing section 2. Absent.

In this embodiment, the case where the cylindrical diffusing portion 2 is milky white is shown. However, the cylindrical diffusing portion 2 having a color capable of irradiating diffused light having a specific wavelength to the object to be inspected may be used. Good. This makes it possible to obtain a filter effect that can enhance reflected light of a specific wavelength. Further, by mounting the cylindrical diffusion part 2 so that it can expand and contract, it becomes possible to cope with changes in the working distance from the inspection object. Further, in the present embodiment, the semiconductor device 10 in the embossed tape 10a to which the cover tape 10b is pasted has been described as an object to be inspected, but the present invention is not limited to this, and the surface of a wafer or the surface of a CD (compact disk) is described. The same applies to the case of inspecting a glass surface or the like having a lot of surface reflection, or a surface having a complicated shape and a lot of irregular reflection.

[0026]

As described above, the visual inspection illumination device of the present invention has the following effects. That is,
In the present invention, since the light from the emitting means is diffused through the cylindrical diffusing means and applied to the inspection object, the diffused light is uniformly reflected without causing total reflection or strong local diffuse reflection. It becomes possible to obtain various reflected light. For this reason, a CCD camera can obtain a high-quality image with less noise, and an accurate visual inspection can be performed. Further, it becomes unnecessary to adjust the angle with respect to the emitted light, and the appearance inspection can be performed very easily. In particular, the present invention is effective when inspecting an object to be inspected with many reflections.

[Brief description of drawings]

FIG. 1 is a schematic sectional view illustrating an embodiment of the present invention.

FIG. 2 is a plan sectional view illustrating another example.

3A and 3B are schematic cross-sectional views illustrating a conventional example, in which FIG. 3A is for epi-illumination, and FIG. 3B is for oblique illumination.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Illumination device for appearance inspection 2 Cylindrical diffusion part 3 Ring-shaped light source 10 Semiconductor device 10a Embossing tape 10b Cover tape 11 CCD camera 21 In-cylinder 31 Light emitting part 32, 32 'Diffusion plate

Claims (2)

[Claims] 1. An illuminating device for appearance inspection, which irradiates light to the object to be inspected to obtain reflected light when inspecting the appearance of the object to be inspected. A cylindrical diffusing means arranged substantially vertically, and an irradiating means arranged outside the cylinder of the cylindrical diffusing means for irradiating the cylindrical diffusing means with light, wherein the light radiated from the irradiating means is A visual inspection illumination device, characterized in that the diffused light is diffused through a cylindrical diffusing means, and the diffused light is applied to the object to be inspected from inside the cylinder of the cylindrical diffusing means to obtain reflected light. 2. The illumination device for appearance inspection according to claim 1, wherein the irradiation unit includes a diffusion plate for diffusing the light with which the cylindrical diffusion unit is irradiated.