JPS6329950A - Forming method for metallic wiring pattern of semiconductor device - Google Patents

Abstract

PURPOSE:To reduce the depth of side etching from the boundary of the outer edge of a photo-resist mask, and to form a metallic wiring having high precision by dividing the temperature of an etchant into high and low values, parting a process into two stages and etching a metallic film. CONSTITUTION:The temperature of an etchant is divided into high and low values, a process is parted into two stages, and the upper layer of a metallic film 2 is etched only by a proper quantity by the etchant held at the high temperature as a first process (a, b). The residual metallic film 2 is all removed by the etchant kept at the low temperature as a second process (c, d). The metallic film 2 consists of an aluminum film, the etchant mainly comprises phosphoric acid, and a range of approximately 50-60 deg. is used as the high temperature and a range of approximately 20-30 deg. as the low temperature. Accordingly, the depth of side etching 4 from the boundary of the outer edge of a photo-resist mask can be reduced, thus shaping a metallic wiring having high precision. Several dozen wafers can be treated simultaneously, thus acquiring high productive efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a semiconductor device, and particularly to the formation of a metal wiring pattern.

[Conventional technology]

Conventionally, in the metal wiring pattern forming method for semiconductor devices, a metal wiring pattern is coated on a semiconductor substrate using a mask such as gold or photoresist pattern. A metal wiring pattern was formed by completely immersing the semiconductor substrate in an etching solution kept at a temperature of 100°C and etching all of the gold PAm.

[The point of view while the invention is trying to solve]

In the conventional metal wiring pattern bottom method described above, the entire metal wiring pattern is etched once in an etching process kept at a relatively high temperature.
+Due to etching, the layer quality between the resist and the metal film surface deteriorates and side etching is likely to occur.) Patterning ridges are significantly reduced, and irregularities occur at the edges of the pattern due to bubbles caused by chemical reactions. There were very few defects that could lead to failure.

SUMMARY OF THE INVENTION An object of the present invention is to provide a metal wiring pattern forming method that eliminates the above-mentioned drawbacks and improves the processing method.

[Means to solve the problem]

In the present invention, the temperature of the etching liquid is divided into high and low, and the process is performed in two stages.The first step is to maintain the temperature at a high temperature and etch the entire upper layer of the etching liquid in an appropriate amount.
The process uses an etching solution kept at a low temperature to remove all remaining metal film.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing the process order of the invention fully applied to aluminum wiring formation. First, as shown in Figure 1 (,): a semiconductor substrate 1 on which elements are formed;
On the entire surface, an aluminum layer 2 is formed using a sputtering method, and then a photoresist is completely coated and patterned to form a photoresist mask 3.

Phosphoric acid kept at approximately 50° to 60° as the first step to the arrow? The entire semiconductor substrate 1 is immersed in basic VcA t aluminum etching solution, the photoresist mask 6 is used, and only the upper layer of the aluminum film 2 is etched to a predetermined thickness. Figure 1(b) shows the etching state.
Etching progresses from the outer edge boundary between the photoresist mask 3 and the aluminum film 2, and side etching portions 4 are formed as shown in the figure. On the other hand, in the conventional method, the metal film is etched one step at a time, so when an aluminum film of the same thickness is etched under the same conditions, the side etched portions A are formed deeply as shown in FIG. If the temperature of the etching solution is high, the adhesion between the photoresist mask 3 and the aluminum group 2 will decrease, and the etching will progress uniformly, so the depth and lateral dimensions of the side etched portions 4 and 4' will be reduced. The thickness of the etched film varies. Therefore, the side etching portion 4' in FIG. 2 is extremely deep, but in the present invention, the side etching portion 4 can be kept shallow.

Next, in the second step, the solution temperature is set to approximately 20° to 30'C, the etching solution is immersed in the same etching solution, and as shown in FIG. 2 is removed and metal wiring 5t- is formed. At this time, since the etching solution is at a low temperature, the adhesion between the photoresist mask 3 and the aluminum 2 does not deteriorate, the progress of side etching is small, and the depth of the side etched portion 4 (1) is reduced to that of the side etched portion 4. It is only slightly larger than the depth.

After etching is completed, the photoresist mask 3 is removed by a conventional method as shown in FIG. 1(d).

〔Effect of the invention〕

As explained above, in the VC twist of the present invention, the depth of side etching from the boundary of the outer vein of the photoresist mask can be reduced, so that the entire metal wiring can be formed with a good degree of edge. In the conventional process, 9 wafers are processed per carrier.If the number of wafers is increased, the yield drops rapidly, so the number of wafers is reduced, but in the present invention, it is possible to process at least one or several dozen wafers at the same time. can be achieved, resulting in high production efficiency.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the process of the present invention, and FIG. 2 is a cross-sectional view of a conventional example for comparison. 1... Semiconductor substrate 2... Aluminum film, 6
... Photoresist mask% 4,4 (1λ4'...
・Side etching part, 5...metal wiring.

Claims (2)

[Claims] (1) In the process of patterning a metal film with an etching solution using a photoresist as a mask to form wiring, the temperature of the etching solution is divided into high and low temperatures, and the process is divided into two stages.The first step is the etching solution kept at a high temperature. A method for forming a metal wiring pattern for a semiconductor device, characterized in that the upper layer of the metal film is etched by an appropriate amount by etching, and as a second step, the remaining metal film is completely removed using an etching solution kept at a low temperature. (2) In the above item 1, the metal film is an aluminum film, the etching solution is mainly composed of phosphoric acid, and the temperature is approximately 50° to 60° as a high temperature and approximately 20° to 30° as a low temperature. A metal wiring pattern forming method according to claim 1, characterized in that: