JPH0637427A - Manufacture of copper polyimide wiring board and structure thereof - Google Patents

Abstract

PURPOSE:To prevent a short-circuit between the neighboring wiring parts in a product by forming dams of polyimide resin on the surface of a substrate material in reverse phase to a wiring pattern. CONSTITUTION:Dams 3 of polyimide resin having unevenness in reverse phase to a purposed wiring pattern are formed on a substrate 1. Next, a conductive foundation thin film 4 and a resist layer 5 are by turns formed on the drams 3 for being made a wiring board material and for performing patterning to the resist layer 5 so as to perform a developing treatment. Thereby, a resist layer 5 exsisting on the second regions B excepting the first regions A corresponding to the top faces of the dams 3 is removed so as to expose a foundation thin film 4 of the second regions B while forming the wiring parts of copper on the foundation thin film in the second exposed regions by electrolytic plating. Then, the resist layer 5 of the first regions A is peeled off so as to expose the foundation thin film 4 of the first regions A wile finally performing an etching treatment for removing the foundation thin film 4 of the first regions A so as to obtain a desired wiring pattern.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a copper-polyimide wiring board formed by using thin film technology on a multilayer ceramic substrate.

[0002]

2. Description of the Related Art A copper polyimide wiring board is constructed according to a process as shown in FIG. First, the ceramic substrate 21
A polyimide resin is applied to form an insulating polyimide layer 22, and a conductive underlying thin film 23 made of chrome, copper or the like is formed on the polyimide layer 22 (FIG. 2).
a).

Next, a resist layer 24 is formed on the underlying thin film 23, a photographic technique is applied to the resist layer 24 to perform patterning, and development processing is performed to remove unnecessary portions (FIG. 2B). This is subjected to electrolytic plating to form a copper wiring portion 25 on the removed portion of the resist layer (FIG. 2c). Next, the wiring section 25
The resist layer 24 remaining between the layers is removed and removed, and the exposed portion of the underlying thin film 23 is removed by wet etching (FIG. 2d).

[0004]

In such a conventional copper-polyimide wiring board, since the side wall of the wiring portion 25 left after removing the resist layer 24 has an overhang-like slope, it is etched. When the wiring board is dipped in the treatment liquid during the treatment, the air in the groove between the adjacent wiring portions 25 is difficult to escape, and this may remain as bubbles 26 as shown in FIG. 2d. This tendency is particularly strong in the case of a fine mesh pattern used as a wiring for a power supply.

The presence of such bubbles prevents the treatment liquid from reaching the underlayer thin film 23, and the underlayer thin film in this portion remains without being etched, resulting in a short circuit between adjacent wiring patterns when the product is a product. It is not preferable. The present invention solves the above problems in the prior art, a method for producing a copper polyimide wiring board in which bubbles do not adhere to the space between adjacent wiring portions during etching, and a unique method obtained by the method. An object is to provide a wiring board having a structure.

[0006]

The object of the present invention is to form a dam of polyimide resin having concavities and convexities of reverse phase shift with respect to a target wiring pattern on a substrate, and to form a conductive base thin film on the dam. A resist layer is sequentially formed to form a wiring board material, and the resist layer is patterned and developed to be present in a second region other than the first region corresponding to the top surface of the dam. The resist is removed to expose the underlying thin film in the second region, and a copper wiring portion is formed on the exposed underlying thin film in the second region by electrolytic plating.
A copper polyimide wiring board, characterized in that the resist in the first region is peeled off to expose the underlying thin film in the first region, and an etching process is performed to remove the underlying thin film in the first region to obtain a desired wiring pattern. Manufacturing method and copper characterized in that a polyimide resin dam is arranged on the surface in a phase opposite to that of the wiring pattern, and the copper wiring pattern is arranged on a plane substantially corresponding to the top surface of the dam. Achieved by a polyimide wiring board.

[0007]

Since the dam of the polyimide resin is previously formed on the surface of the wiring board material, the underlying thin film to be removed by the etching process remains only on the top surface of the dam.
Therefore, adhesion of bubbles to the surface of the underlying thin film does not occur,
The treatment liquid easily contacts the underlying thin film and completely removes it. Therefore, it is possible to prevent a short circuit from occurring between the adjacent wiring portions due to the remaining base thin film.

Hereinafter, based on the preferred embodiment shown in the drawings,
The present invention will be described in more detail.

[0009]

EXAMPLE FIG. 1 shows a manufacturing process of a copper polyimide wiring board by the method of the present invention. First, a polyimide resin is applied on the ceramic substrate 1 to form a polyimide layer 2 as usual. (FIG. 1a) Next, a photosensitive wiring of a polyimide resin is used to print a mesh-shaped wiring pattern, and a development process is performed to form a plurality of polyimide resin dams 3 that are regularly arranged in positions opposite to the wiring pattern. . First the area where this dam is formed
It is called area A. (FIG. 1b) When the size of the mesh is 25 μm square, the height of this dam is preferably about 13 μm, and the width of the lower part is preferably about 25 μm.

A conductive base thin film 4 is formed on the polyimide layer 2 and the dam 3 thus formed, and a resist layer 5 is further formed thereon. (FIG. 1c) Next, a wiring pattern is printed again, and the resist layer 5 on the top of the dam 3, that is, the resist layer in the first region A is exposed to light,
After development, only the first region is left and the remaining resist layer in the second region B is removed to expose the underlying thin film 4 in the second region on the surface. (FIG. 1d) Then, the copper wiring portion 6 is formed on the exposed underlying thin film of the second region B by electrolytic plating. (Fig. 1
e) Finally, the remaining resist layer 2 in the first area A is peeled off to expose the underlying thin film 4, and in this state, the underlying thin film 4 in the first area A is removed by etching. (Fig. 1
f) During the etching process, the underlying thin film in the first region A is lined up on substantially the same plane as the wiring portion 6 in the second region B adjacent to the first region A, so that the contact with the processing liquid becomes good, and Problems such as air bubble entrapment that often occur in technology do not occur. Therefore, the underlying thin film 4 is completely removed, and the defects due to the short circuit between the wiring portions are reduced.

In the copper polyimide wiring board thus obtained, dams of polyimide resin are regularly scattered on the surface, and a conductor pattern is arranged in a mesh between these dams. Further, when viewed in cross section, the wiring portion 6 and the top surface of the polyimide resin dam 3 form a unique structure in which they are arranged substantially on one plane.

[0012]

According to the present invention, the polyimide resin dam is formed on the surface of the substrate material in a phase opposite to that of the wiring pattern. Therefore, after the wiring portion is formed, the underlying thin film to be removed is the top of the dam. It remains only on the surface. Therefore, the underlying thin film can be easily brought into contact with the etching solution and completely corroded and removed, thereby preventing a short circuit between adjacent wiring parts in the product.

A barrier metal film is usually formed on the surface of the wiring portion in order to prevent copper forming the wiring portion from diffusing and penetrating into the polyimide layer. In the past, it was difficult to form this barrier metal film on the side wall region of the wiring part having an overhang shape, but since the side wall of the wiring part is substantially absent in the present invention, such a problem does not occur.

[Brief description of drawings]

FIG. 1 is a sectional view showing a manufacturing process of a copper polyimide wiring board according to the present invention.

FIG. 2 is a cross-sectional view showing a manufacturing process of a conventional copper polyimide wiring board.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Ceramic substrate 2 ... Polyimide layer 3 ... Dam 4 ... Base thin film 5 ... Resist layer 6 ... Wiring part A ... 1st area | region B ... 2nd area | region

Claims (2)

[Claims] 1. A dam (3) made of polyimide resin having an unevenness of a phase shift opposite to that of a target wiring pattern is formed on a substrate (1), and a conductive base thin film (4) is formed on the dam (3). ) And a resist layer (5) are sequentially formed to form a wiring board material,
By patterning and developing the resist layer (5), the resist layer existing in the second region (B) other than the first region (A) corresponding to the top surface of the dam (3). (5) is removed to expose the underlying thin film (4) in the second area (B), and the exposed underlying thin film (4) in the second area (B) is electroplated to form a copper wiring portion (6). ) Is formed, the resist layer (5) in the first region (A) is peeled off to expose the underlying thin film (4) in the first region (A), and an etching process is performed to form the underlying film in the first region (A). A method for producing a copper-polyimide wiring board, which comprises removing the thin film (4) to obtain a desired wiring pattern. 2. A plurality of dams (3) made of polyimide resin are arranged on the surface in a phase opposite to that of the wiring pattern (6), and the top surface of the dam (3) is provided in a recess between adjacent dams (3). And a copper wiring pattern (6) arranged substantially in one plane.