JP2004347913A - Resist inspection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inspection method by which the edge of a resist pattern is more sharply displayed while an unexposed resist is prevented from exposure when an exposed part of the resist layer is optically inspected after the resist layer on a substrate is exposed or after the exposed resist layer is developed. <P>SOLUTION: In the process of optically inspecting an exposed part of the resist layer after the resist layer on the substrate is exposed or after the exposed resist layer is developed, the wavelength of light used for illumination is specified to 522 to 645 nm. Preferably, if the resist is prepared by using a dry film resist, the resist is irradiated with the light at 522 to 645 nm wavelength from the direction orthogonal to the direction where the dry film is stretched when the resist is stuck to the substrate, and more preferably, the exposed part is photographed by using a line CCD camera. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to process control when producing electronic components such as TAB tapes and printed wiring boards, and more specifically, to process control performed after exposing or developing a resist layer using a mask having a desired pattern. The inspection method.
[0002]
[Prior art]
Resists are often used in the manufacture of mounting parts for semiconductor devices such as TAB tapes and printed wiring boards. For example, when manufacturing a TAB tape using an insulating film provided with a metal layer on its surface, a dry film is attached to the metal layer surface, or a liquid resist is applied to provide a resist layer, and a wiring pattern is formed. UV irradiation (this operation is referred to as “exposure”) is performed through a mask to expose a desired portion of the resist layer, and then developed to remove an exposed or unexposed portion to obtain an etching mask having a wiring pattern. . Thereafter, the exposed metal layer portion is dissolved and removed, and then the remaining resist layer is removed to obtain a wiring pattern. After that, a resist layer is provided again on the surface of the wiring portion, exposed through a mask having a plating pattern, developed and exposed to be plated, and a desired metal is plated on the exposed metal layer surface. Get the product.
[0003]
Inspections are performed at the main parts of these manufacturing processes, and process management is performed to prevent the occurrence of defective products. One of such inspections is to optically inspect whether an etching mask or a plating mask obtained after exposing or developing a resist layer is in a good state. This is because, when exposed, the exposed part and the unexposed part have different surface colors, and when developed, the part removed by development shows the metal surface whereas the part that is not removed has a resist layer Therefore, the fact that the colors of both surfaces are different is used.
[0004]
At this time, generally, in order to eliminate the complexity of changing the light source between after exposure and after development, a yellow ring fluorescent lamp, which hardly affects the unexposed resist, is used as a light source to irradiate and image the resist layer surface. I have.
[0005]
However, this method has a problem in that the boundary between the exposed portion and the unexposed portion (hereinafter, referred to as “pattern edge”) is not clearly seen and is blurred, so that it is not possible to accurately judge the quality.
[0006]
[Problems to be solved by the invention]
The present invention has been made in order to solve the above situation, and an object thereof is to form a resist layer after exposing a resist layer of a substrate having a resist layer, or after developing the exposed resist layer. It is an object of the present invention to provide an inspection method for optically inspecting a photosensitive portion, in which edges of a pattern of a resist are more clearly projected and an unexposed resist is not exposed.
[0007]
[Means for Solving the Problems]
The invention according to claim 1, which solves the above problem, is to optically inspect a photosensitive portion of a resist layer after exposing a resist layer of a substrate having the resist layer or after developing the exposed resist layer. The wavelength of the illumination used is 522 to 645 nm.
[0008]
The invention according to claim 2 provides that, when the resist is formed using a dry film resist, the wavelength 522 is from a direction perpendicular to a direction in which the dry film resist is stretched when being attached to the substrate. Irradiates 645 nm light.
[0009]
According to the third aspect of the present invention, when an image is taken using a line CCD camera, light having a wavelength of 522 to 645 nm is irradiated from a direction perpendicular to a direction in which the dry film resist is stretched when the dry film resist is attached to the substrate. Things.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
After exposing the resist layer provided on the substrate or after developing after exposure, in order to more clearly optically detect the boundary between the resist layer portion that has been discolored by exposure to light and the unexposed and undiscolored portion It is required that the irradiation light used for imaging has a wavelength that does not reflect on the discolored portion and does not affect the unexposed portion.
[0011]
The present inventors have examined the light in the visible region that meets the above conditions, and have found that light in the wavelength region of 522 to 645 nm can be used. When irradiated with light having a wavelength in this region, the exposed photoresist layer portion absorbs the irradiated light, and the other unexposed and unexposed portions are removed and the exposed metal surface transmits and reflects the irradiated light. Thus, the boundary between the exposed resist layer portion and other portions can be clearly imaged.
[0012]
When the resist layer is formed using a dry film resist, the dry film resist is attached while being stretched in the unwinding direction of the raw material. Therefore, the photosensitive agent in the dry film resist is also stretched in the unwinding direction of the raw material of the dry film resist. Therefore, by irradiating light from a direction perpendicular to the direction in which the dry film resist is stretched, the boundary between the photosensitive portion and the other portion can be more clearly detected.
[0013]
In general, it is technically difficult to irradiate illumination with high anisotropy over a wide range, but it is easy to realize illumination with high anisotropy only on linear portions. When taking an image with a line CCD camera, it is only necessary to realize highly anisotropic illumination only on a linear portion, so that it is easy to obtain a high quality image. At this time, for the same reason as above, linear illumination is applied from a direction perpendicular to the direction in which the dry film resist is stretched, and the longitudinal direction of the line CCD is set in a direction parallel to the direction in which the dry film resist is stretched. The CCD is scanned in a direction perpendicular to the longitudinal direction of the CCD.
[0014]
【Example】
Next, the present invention will be further described using examples.
(Example 1)
The following test was performed using a printed circuit board having a copper foil (including copper plating) having a thickness of 27 μm adhered to one surface of an insulating substrate.
A dry film resist manufactured by Asahi Kasei Corporation was attached to the surface of the copper foil of the printed circuit board, and then a pattern mask was brought into close contact with the surface of the dry film resist to expose the dry film resist to light.
All of the exposed patterns were irradiated with light in a wavelength range of 522 to 645 nm and imaged by a CCD camera, and their quality was determined, and this was performed for 50 types. As a result, a pass rate of 85% was obtained.
[0015]
(Example 2)
Example 1 Example 1 was performed using the 50 patterns used in the measurement in Example 1 except that light in a wavelength range of 522 to 645 nm was irradiated from a direction perpendicular to the direction in which the dry film resist was attached to the substrate. Pass / fail was determined in the same manner as described above. As a result, a pass rate of 95% was obtained.
[0016]
(Example 3)
The following test was performed using a printed circuit board having a copper foil (including copper plating) having a thickness of 27 μm adhered to one surface of an insulating substrate.
A dry film resist manufactured by Asahi Kasei Corporation was attached to the surface of the copper foil of the printed circuit board, and then a pattern mask was brought into close contact with the surface of the dry film resist to expose the dry film resist to light. Next, this was developed, and the unexposed portion was removed to expose the copper foil layer.
The pattern in this state was irradiated with light in the wavelength region of 522 to 645 nm, imaged by a CCD camera, and its quality was determined. As a result, a pass rate of 90% was obtained.
[0017]
(Example 4)
Example 1 Example 50 was performed using the 50 types used in the measurement in Example 3 except that light in a wavelength region of 522 to 645 nm was irradiated in a direction perpendicular to the direction in which the dry film resist was attached to the substrate. Pass / fail was determined in the same manner as described above. As a result, a pass rate of 99% was obtained.
[0018]
(Comparative Example 1)
Using the 50 patterns used in the measurement in Example 1, the light for imaging was imaged with a CCD camera using the irradiation light of a yellow ring fluorescent lamp, and the quality was judged. As a result, a pass rate of 70% was obtained.
[0019]
(Comparative Example 2)
Using the 50 types used in the measurement in Example 3, the light for imaging was imaged with a CCD camera for all the patterns using the irradiation light of a yellow ring fluorescent lamp, and the quality was judged. As a result, a pass rate of 80% was obtained.
[0020]
【The invention's effect】
The present invention provides a method for optically inspecting a pattern of a photosensitive portion of a resist that has been discolored after exposing or developing a substrate coated or pasted with a resist, and clearly captures a boundary between the exposed portion of the resist and other portions. Therefore, a highly accurate optical inspection can be performed.
[0021]
When the resist is a dry film resist, by irradiating light from a direction perpendicular to the direction in which the dry film resist is stretched, the photosensitive portion of the dry film resist after exposure or development and the other portions are exposed to light. Since the image can be clearly captured by making the boundary more prominent, a high-precision optical inspection can be performed.
[0022]
By using a line CCD camera, higher quality anisotropic illumination can be realized, and the boundary between the exposed part and the other part of the dry film resist after exposure or development is sharpened and the image is sharpened. Therefore, high-precision optical inspection can be easily realized.

Claims (3)

When exposing a resist layer of a substrate having a resist layer or developing the exposed resist layer and then optically inspecting a photosensitive portion of the resist layer, a resist inspection using an illumination wavelength of 522 to 645 nm is used. Method. 2. The method according to claim 1, wherein when the resist is formed using a dry film resist, light having a wavelength of 522 to 645 nm is irradiated from a direction perpendicular to a direction in which the dry film resist is stretched when the dry film resist is attached to a substrate. Resist inspection method. 3. The method according to claim 2, wherein the image is taken using a line CCD camera.