JPH058458U - Lighting device for defect inspection - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an illuminating device that illuminates so that defects on the upper surface of the inspection object can be clearly identified. [Structure] A ring-shaped light source 13 that emits irradiation light toward the lower side is arranged above the lead pattern 11 that is the inspection object, and the outer periphery of the lead pattern 11 is placed between the lead pattern 11 and the ring-shaped light source 13. The ring mirror 14 is arranged so as to surround it, and the irradiation light from the ring light source 13 is reflected by the ring mirror 14 toward the upper surface of the lead pattern 11 obliquely from above with a desired depression angle from the entire circumference.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an illuminating device for defect inspection suitable for inspecting defects such as pinholes on a lead pattern formed on a TAB (Tape Automated Bonding) tape.

[0002]

[Prior Art]

 In recent years, the TAB method has been attracting attention as a bonding technique for mounting an electronic device such as an LSI chip used for a liquid crystal display driver on a substrate. This TAB method has various advantages that it can respond to the demand for a large number of pins as the functionality of the device becomes higher, and it can be made thinner and smaller, and the packaging density can be increased. The TAB tape used in the TAB method is a punching process for punching device holes and perforations on a film tape such as polyimide, a process for attaching copper foil to a punched film tape, and a photoresist applied on the copper foil. After that, it is manufactured through a step of exposing and developing, an etching step of forming a lead pattern by etching, and the like.

By the way, in the etching process for forming a lead pattern on a TAB tape, if a pinhole or a flaw is generated in the photoresist layer for forming the lead pattern, a copper foil corresponding to the pinhole or the flaw is formed. A pit (pinhole) is formed on the top.

FIGS. 4A to 4C show a process in which a depression is generated on a pattern due to a pinhole or a scratch in the photoresist layer. In FIG. 4, 1 is a film tape made of polyimide or the like, 2 is a copper foil stuck on the film tape 1, 3 is a photoresist for forming a lead pattern, and 3a is a pinhole or a scratch generated in the photoresist 3. Is. When the film tape having the structure shown in FIG. 4 (a) is immersed in the etching solution, the copper foil other than the portion covered by the photoresist 3 is removed, and the lead pattern 4 is formed as shown in FIG. 4 (b). Is formed. At the same time, the etching liquid that has penetrated from the pinholes or the scratches 3a of the photoresist 3 erodes the upper surface of the lead pattern 4. As a result, recesses (or pinholes) 5 are formed on the upper surface of the lead pattern 4 after the photoresist 3 is removed, as shown in FIG.

Conventionally, in the case of inspecting defects such as depressions formed on the upper surface of the lead pattern, it is the current situation to illuminate the upper surface of the lead pattern and visually using a loupe or the like.

[0006]

[Problems to be solved by the device]

 However, in visual defect inspection, defects are visible or invisible depending on the illumination direction of the lead pattern, which increases the burden on the inspector. In addition, there is a problem that the productivity of TAB tape is low and the cost is high because the inspection efficiency is limited due to the manual work. The present invention has been devised in view of the above circumstances, and provides a lighting device for defect inspection, which is suitable for a case where an inspection device that clearly and automatically identifies a defect on the upper surface of an object to be inspected is configured. With the goal.

[0007]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention provides a light source, which is disposed above an object to be inspected and surrounds the outer periphery of the object to be inspected, and which emits irradiation light toward the object to be inspected. And a mirror that is disposed between the light source and that reflects the irradiation light so that the irradiation light from the light source is irradiated obliquely above the inspection object to the upper surface of the inspection object at a desired depression angle. It is characterized by that.

[0008]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of an illumination device according to the present invention used for defect inspection of a lead pattern on a TAB tape. In FIG. 1, 10 is a TAB tape which is continuously fed in the direction of arrow X, and a large number of lead patterns 11 for bonding IC chips are formed on the surface thereof at intervals in the longitudinal direction.

Reference numeral 12 is an illuminating device which is arranged immediately above the TAB tape 10 and in proximity thereto. This illuminating device 12 is for illuminating the upper surface of the lead pattern 11 from diagonally above so as to surround the outer periphery of the lead pattern 11, and has a ring shape for generating a ring-shaped line light toward the lower side. The light source 13 and a ring-shaped mirror 14 that reflects the ring-shaped line light 13a generated from the ring-shaped light source 13 toward the upper surface of the lead pattern 11 obliquely from above. The ring-shaped mirror 14 redirects the irradiation light from the ring-shaped line light 13a into parallel light having a depression angle of about 30 degrees with respect to the upper surface of the pattern and directs it toward the upper surface of the lead pattern 11 ( It has a paraboloid of revolution 14a.

Reference numeral 15 denotes an image pickup camera including a CCD image sensor and the like arranged above the illuminating device 12 so as to coincide with the central axis of the illuminating device 12, and photographs the lead pattern 11 transferred onto the optical axis thereof. The image signal captured by the image capturing camera 15 is output to the image processing device 16.

Next, the operation will be described. When the lead pattern 11 on the TAB tape 10 transferred on the lower surface of the illuminating device 12 is located at the center of the lower surface of the ring-shaped mirror 14, the imaging camera 15 operates to image a predetermined area including the lead pattern 11. At this time, the ring-shaped line light 13a generated from the ring-shaped light source 13 of the illumination device 12 is reflected in the direction of the arrow shown in FIG. Is illuminated at a depression angle of 30 ° from diagonally above the outer periphery centered on the lead pattern 11. When such a illuminating light is applied to the depression 11a formed on the upper surface of the lead of the lead pattern 11, the inner surface reflection as shown in FIG. 2 occurs, and the brightness of the edge portion 11b increases, so that the depression 11a The contour is clarified.

For example, if the cross-sectional shape of the lead pattern 11 after etching is a shape having a depression 11a as shown in FIG. 3A, the lead pattern 11 is exposed to illumination light from the upper surface direction indicated by arrow A. When irradiated, the output signal waveform with respect to the luminance of the CCD image sensor of the imaging camera 15 is as shown in FIG. Further, the output signal waveform with respect to the brightness when the illumination light is irradiated from diagonally above (the angle of 30 ° with respect to the horizontal plane) shown by the arrow B in FIG. 3A is as shown in FIG. The output level of the portion corresponding to the depression 11a is higher than the others. Further, when the illumination light is irradiated from right beside shown by the arrow c in FIG. 3A, the output signal waveform shown in FIG. 3D is obtained. That is, when detecting a depression (or a pinhole) generated on the upper surface of the lead pattern 11, it is most effective to irradiate the irradiation light obliquely from above the lead pattern 11.

As described above, the upper surface of the lead pattern 11 in which the contour of the depression 11a is clarified by the irradiation light is imaged by the imaging camera 15, and the image is converted into an electric signal by the built-in CCD image sensor unit, and at the same time, The scanning means of the image sensor unit sequentially reads out the respective scans and inputs them to the image processing device 16. The image processing device 16 processes the input image data to determine whether or not there is a depression on the upper surface of the lead pattern 11.

As described above, according to this embodiment, the lighting device 12 surrounding the lead pattern 11 on the TAB tape 10 and its outer periphery is obliquely upward and the entire circumference of the periphery at a depression angle of about 30 ° with respect to the horizontal plane. Since the illumination light is emitted from the above, the recess 11 a eroded by the etching liquid by the pinhole of the resist or the like on the upper surface of the lead pattern 11 can be emphasized in terms of brightness. Along with this, the input image of the depression 11a by the imaging camera 15 becomes clear, the image processing becomes easy, and the depression formed on the upper surface of the lead pattern 11 can be surely recognized, and the inspection can be automated easily. .

The present invention is not limited to the defect inspection of the lead pattern, but can be applied to the defect inspection of various other product surfaces.

[0016]

[Effect of the device]

 As described above, according to the present invention, the luminous flux of the illumination light emitted from the light source located above the object to be inspected and surrounding the outer periphery is disposed between the object to be inspected and the light source. Since the mirror is bent so as to irradiate the upper surface of the inspection object at a desired depression angle from the obliquely upper side of the inspection object, the contour of the defect generated on the upper surface of the inspection object is changed in brightness. Can clarify and highlight defects. Along with this, it becomes easy to recognize defects, and it is possible to obtain an illuminating device for defect inspection, which is suitable when an inspection device that clearly and automatically identifies defects on the upper surface of the inspection object is configured.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an illumination state of a depression in the present embodiment.

3A to 3D are explanatory diagrams showing the direction of illumination light with respect to a lead pattern and the state of an output waveform corresponding to this direction.

4 (a) to 4 (c) are explanatory views showing a process of forming a dimple on the upper surface of the lead pattern with an etching solution.

[Explanation of symbols]

 10 TAB Tape 11 Lead Pattern 11a Dimple 12 Illuminator 13 Ring Light Source 14 Ring Mirror 14a Curved Surface

Claims (1)

Claims for utility model registration: 1. A light source, which is disposed above an object to be inspected and surrounds the outer periphery of the object to be inspected, and which emits irradiation light toward the object to be inspected. A mirror which is arranged between the inspection object and the light source, and which reflects the irradiation light so that the irradiation light from the light source is applied obliquely above the inspection object to the upper surface of the inspection object at a desired depression angle. An illuminating device for defect inspection, comprising: