JPS63146451A - Formation of interconnection pattern - Google Patents

Abstract

PURPOSE:To stabilize the strength by etching away the unnecessary plating supply layer part after forming a third photoresist pattern covering the plating metal layer part, thereby eliminating the etching of the plating metal layer surface. CONSTITUTION:A photoresist 2 is applied on a semiconductor substrate 1 and patterned, forming a plating supply metal layer 3. Then, a second photoresist is applied and patterned, and after performing an electrolytic plating to grow a plating metal layer 4, the second photoresist is removed. Next, a third photoresist 222 is applied and patterned, selectively covering the plating metal layer 4 part. Subsequently, the unnecessary part of the plating supply metal layer 3 is etched away, and then the first and third photoresists 2, 222 are removed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for forming a fine wiring pattern on a semiconductor substrate, and particularly to a method for forming an air bridge.

(Prior Art) Figures 2(a) to 2(h) show main parts showing the main manufacturing process sequence of an example of a conventional method for forming a bridge-like three-dimensional metal fine wiring pattern (air bridge) on a semiconductor substrate. In the broken cross-sectional view,
Hereinafter, the conventional method will be explained using this.

In FIG. 2, 1 is a semiconductor substrate, 2 and 22 are first and second photoresist layers, respectively.

3 is a plating power supply metal layer, and 4 is a plating metal layer.

Next, the manufacturing process order will be explained.

First, as shown in FIG. 2(a), a first photoresist 2 is coated and patterned on a semiconductor substrate 1, and then,
A plating power supply metal layer 3 is formed on the photoresist pattern by vapor deposition or sputtering (FIG. 2(b)), and then a second photoresist 22 is applied (FIG. 2(C)). Then, a bridge-like three-dimensional resist-free portion is formed as shown in FIG. 2(d).

Next, electrolytic plating is performed to selectively grow a plating metal layer 4 only in the resist-free areas (FIG. 2(e)),
Thereafter, the second photoresist layer 22, the unnecessary portion of the plating power supply metal layer 3, and the first photoresist layer 2 are sequentially removed (FIG. 2(f) to (h)) to obtain an air bridge. A similar pattern format method was used.

[Problem that the invention seeks to solve]

However, according to the conventional method for forming fine wiring patterns as described above, the surface of the plating metal layer 4 is also etched in the step of etching unnecessary parts of the plating power supply metal 3 after electrolytic plating (FIG. 2(g)). This will cause loss of bite and surface roughness.

In particular, in the case of fine air bridges having a line width of 1 to 2 .mu.m, problems arise such as not only the thinning of the plated metal layer 4 and the roughened surface of the wiring, but also the appearance of the wiring, which also adversely affects the strength.

This invention was made in view of the problems of the conventional methods as described above, and aims to provide a method for obtaining fine air bridges with good appearance and stable strength with good reproducibility. .

[Means for solving problems]

Therefore, in the method for forming a fine wiring pattern according to the present invention, after the electrolytic plating step and the second photoresist removal step, a third photoresist pattern that covers the plating metal layer portion is formed, and then, The above objective is achieved by etching away unnecessary portions of the plating power supply layer.

[Effect]

According to the method of the present invention as described above, the third photoresist pattern formed to selectively cover the plated metal layer portion is reduced due to the etching of the surface of the plated metal layer during the etching removal process of the unnecessary portion of the plated power supply layer. This can prevent surface roughness, etc.

(Example〕 The present invention will be explained below based on examples.

FIGS. 1(a) to 1(f) are cutaway sectional views of main parts showing the sequence of main manufacturing steps in a fine wiring pattern forming method according to an embodiment of the present invention, and FIGS. 2(a) to 2(f) of the conventional example (h)
The same (equivalent) components as in are represented by the same symbols. 1
2 and 222 are respectively the 17th and 3rd photoresist layers, 3 is a plating power supply metal layer, and 4 is a plating metal layer.

1rA(a) shows a process state similar to that in FIG. 2(f), and in this embodiment method, after this state, as in FIG. 1(b), the third photoresist 222 is coated and patterned to selectively cover the four portions of the plating metal layer. Next, as shown in FIG. 1(C), the plating power supply metal layer 3
The unnecessary portions of the photoresist layer 2 are removed by etching, and the first photoresist layer 2 is then removed to obtain an air bridge as shown in FIG. 1(d).
During etching to remove unnecessary parts of the plating power supply metal layer 3 in FIG.
1/Since it is protected, it will not be adversely affected by etching. This effect can be achieved, for example, when the line width is 1~
This is particularly effective when forming fine air bridges of about 2 μm.

〔Effect of the invention〕

As described below, according to the present invention, it is possible to prevent etching of the surface of the plated metal layer in the process of etching away unnecessary portions of the plated power supply metal layer, and to produce a workpiece with a good appearance and stable strength. It has the effect of obtaining a bridge with good reproducibility.

Figures 1(a) to ← are cutaway cross-sectional views of main parts showing the sequence of main manufacturing steps in a fine wiring pattern forming method according to an embodiment of the present invention, and Figures 2(a) to (h) are conventional FIG. 3 is a fragmentary cross-sectional view of each main part showing the order of manufacturing steps in an example of the method.

1: Semiconductor substrate 2.22, 222: First/second/third photoresist layer 3: Plated power supply metal layer 4: Plated metal layer

Claims (1)

[Claims] In the step of forming an air bridge on the surface of a semiconductor substrate, a step of coating and forming a first photoresist layer on the surface of the semiconductor substrate, and a step of forming a first photoresist layer by photolithography at a position where the bridge girder of the air bridge is located, forming a plating power supply metal layer on the formed pattern by vapor deposition or sputtering; coating and forming a second photoresist layer on the plating power supply metal layer; forming, by photolithography, a pattern of the second photoresist in which a range linearly connecting at least two of the cut-out pattern portions of the first photoresist becomes the cut-out portion; a step of performing electrolytic plating using the second photoresist as a mask, a step of removing the second photoresist, and a step of coating and forming a third photoresist layer, and applying the third photoresist layer only to the portion where the plating pattern is provided by photolithography. A method for forming a wiring pattern, the method comprising: a step of etching away an unnecessary partial layer of the plating power supply metal; and a step of removing the first photoresist layer to obtain an air bridge.