JPS6041235A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To form an external connection terminal (bump) having high density and large strength by performing selectively plating steps several times by using a photoresist. CONSTITUTION:A photoresist is coated on a semiconductor substrate 1 in which the formation of an active region is finished, and a hole B is opened by a photoetching step. Then, a bump 4-1 is formed by plating. Thereafter, a photoresist is again coated, the top of the bump 4-1 is partly opened, and again plated to form a bump 4-2. Thus, the bump is microminiaturized while preventing the strength of the bump from decreasing.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a semiconductor device having external connection terminals with high density and high strength. Commonly used terminals include so-called bonding pads, which have metal protrusions called bumps formed on the terminals, and which connect the protrusions to the metal wiring of external circuits.

The present invention relates to the formation of metal protrusions (hereinafter abbreviated as bumps) corresponding to the latter.

Semiconductor devices are required to be made smaller and more dense in order to improve performance and reduce costs.

In response to such demands, it has become necessary to make the bumps smaller.

The present invention relates to a method for effectively achieving the above object.

Conventionally, bumps were formed by one-time selective plating using a photosensitive resin as a mask after the processing of the active area of a semiconductor device was completed.

FIG. 3 shows a cross-sectional view of a bump formed by a conventional method. As is clear from FIG. 3, the bumps 4 are formed by plating to a height of {circle around (2)}.

In this case, the bump external width A compared to the photoresist opening width B grows almost isotropically so that the relationship A>B-1-2H holds.

The height H of the bump needs to be at least a certain value for reasons such as adhesion and stress absorption when connecting the semiconductor device to an external circuit. Therefore, in order to make A in the external shape of the bump more fine, B must be made smaller, which has the disadvantage of reducing the strength of the bump itself. It is shown in Figure 2.

In the present invention, in order to obtain the height H of the bump, selective plating is performed multiple times to prevent a decrease in the bump strength and to make the bump finer. This will be explained in detail step by step with reference to FIG.

First, as in the conventional method, a photoresist is applied to the semiconductor substrate 1 on which the active region has been formed, and an opening B is made using a known photoresist.
-1 is formed. After that, photoresist is applied again to form 4-1 (7) The upper part is partially opened and plated again to form 4-2.

If a bump of height H is formed by performing selective plating twice in this way, the relationship between the bump's outer shape A, height H, and width B of the plating opening becomes B + H, and A is miniaturized. However, B can be made larger.

If B is increased, the strength of the bumps can be increased, so that fine bumps with high strength can be formed.

FIG. 2 shows a cross-sectional view of a bump formed by performing selective plating three times.

As is clear from the above explanation, according to the method of the present invention, it is possible to change the metal of the first bump 4-1 and the bump 4-2 formed therein, and the plating opening can also be changed. It can also be plated.

In this explanation, we have described a manufacturing method in which bumps are formed by plating two or three times, but it is of course possible to perform plating multiple times in general.

[Brief explanation of drawings]

1 and 2 are cross-sectional views of the bump according to the present invention;
The figure is a cross-sectional view of a bump formed by a conventional method. 1... Semiconductor substrate 2... Surface layer 6 of semiconductor substrate... Electrode 4 of semiconductor device... Bumps 4-1 to 4-3... Bump portions are shown. Applicant Suwa Seikosha Co., Ltd. Agent Patent Attorney Tsutomu Mogami Figure 3

Claims (1)

[Claims] 1. A method of manufacturing a semiconductor device, which comprises performing a selective plating process using a photoresist multiple times to form a metal protrusion in a semiconductor device having a metal protrusion as an external connection terminal.