JPH0766153A - Fabrication of semiconductor device - Google Patents

Abstract

PURPOSE:To effect patterning of electrode wiring layer on a semiconductor substrate by including a step for forming a gold layer on a semiconductor substrate formed with an insulation film having a window, a step for immersing the semiconductor substrate formed with the gold layer into a hydrofluoric acid solution, and a step for washing the semiconductor substrate with water. CONSTITUTION:An insulation film 3 having a window 2 at a region for forming an electrode wiring layer is formed on a semiconductor substrate 1 on which elements are formed and then a gold layer 4 is formed thereon. When the semiconductor substrate 1 is immersed into a hydrofluoric acid solution, the insulation film is etched slightly and the insulation film 3 is eroded below the gold layer 4 which is thereby floated slightly. The semiconductor substrate 1 is then washed with water to remove only the gold layer 4 from the insulation layer 3 thus forming an electrode wiring layer of predetermined pattern. This method eliminates the steps for forming, patterning and removing photoresist film thus reducing the fabrication process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device.

[0002]

2. Description of the Related Art Conventionally, as a method of forming an electrode wiring layer on the surface of a semiconductor substrate on which elements such as diodes, transistors and ICs have been formed, generally, FIG.
It is performed as shown in (d).

That is, as shown in FIG. 2A, on the surface of a semiconductor substrate 11 on which elements are formed, a window hole 12 is provided in a region where an electrode wiring layer is to be formed. The insulating film 13 is formed. And FIG. 2 (b)
As shown in FIG. 5, after depositing an electrode layer 14 made of an electrode material such as gold, aluminum, titanium, etc. on the insulating film 13 having the window 12 formed therein, a photoresist film 15 is patterned on the electrode layer 14. To do. Next, as shown in FIG. 2C, after the semiconductor substrate 11 is immersed in a predetermined etching solution such as potassium iodine iodide solution to remove the metal layer 14 in an unnecessary region on the insulating film 13, As shown in FIG. 2D, the photoresist film 15 is removed by a predetermined organic solvent and washed with water to pattern the electrode wiring layer.

[0004]

As described above, in the conventional method as described above, a photoresist film is formed on the metal layer in order to form the electrode wiring layer by etching and patterning the metal layer. A complicated process such as forming and patterning this with precision is essential. Also, an etching solution used for etching the metal layer,
Since it is necessary to use a plurality of special solutions such as an organic solvent used to remove the photoresist film after etching, there is a danger to the operator, and it is necessary to strictly manage these solutions.

The present invention provides a completely new method of patterning an electrode wiring layer on a semiconductor substrate without the steps of forming, patterning, and removing a photoresist film, which have been conventionally required. is there.

[0006]

As a result of intensive studies to achieve the above object, the present inventor has found that when a metal layer is provided on a semiconductor substrate on which an insulating film having window holes is formed, the metal layer The adhesiveness of the metal layer to the insulating film is poorer than the adhesiveness to the semiconductor substrate, and the difference in the adhesiveness (adhesive force) becomes clearer, especially when immersed in a hydrofluoric acid solution. I found that.

That is, according to the present invention, (a) a step of forming a metal layer on a semiconductor substrate on which an insulating film having window holes is formed,
(B) Manufacture of a semiconductor device including a step of immersing the semiconductor substrate on which the metal layer is formed in a hydrofluoric acid solution, and (c) a step of rinsing the semiconductor substrate immersed in the hydrofluoric acid solution with water It relates to the method.

[0008]

[Function] When an insulating film in which a window hole is formed at a place where an electrode wiring layer is to be formed is formed on a semiconductor substrate, a metal layer is formed on this semiconductor substrate, and the metal layer is immersed in a hydrofluoric acid solution in this state,
Only the insulating film is slightly etched, and the adhesive force between the metal layer and the insulating film can be reduced in a state where the adhesive force between the metal layer at the window hole portion and the semiconductor substrate is kept good. In other words, on the semiconductor substrate, the adhesion of the metal layer on the window portion of the insulating film required as the electrode wiring layer is improved, and the adhesion of the unnecessary metal layer on the insulating film to be removed is further reduced. Will be made. Therefore, if this is washed with water, only the metal layer on the insulating film is peeled and removed, and the metal layer formed in the window hole remains and an electrode wiring layer having a predetermined pattern is formed.

[0009]

EXAMPLES The features of the present invention will be described in more detail by showing examples below, but the present invention is not limited to these examples.

1 (a) to 1 (d) show an embodiment of the present invention. In this example, a gold layer was used as the metal layer.

(A) As shown in FIG. 1A, on the semiconductor substrate 1 on which the element is formed, such as silicon oxide or silicon nitride having a window hole 2 formed in a region where an electrode wiring layer is to be formed. An insulating film 3 (for example, a thickness of about 3.0 μm) is formed, and a gold layer 4 (for example, a thickness of about 0.3 μm) is vapor-deposited on the semiconductor substrate 1 as shown in FIG. 1B. It is formed by the spattering method or the like. At this time, by setting the thickness of the gold layer 4 to about 1/5 or less of the thickness of the insulating film 3,
Since the gold layer 4 can be discontinuous on the insulating film 3 and the portion of the window 2, the removal of the unnecessary unnecessary gold layer 4 (on the insulating film) can be further facilitated, which is more preferable. It is more efficient to use an insulating film formed at the time of forming the element as the insulating film 3.

(B) Next, the semiconductor substrate 1 on which the gold layer 4 is formed as described above is dipped in a hydrofluoric acid solution (for example,
Immerse in a hydrofluoric acid aqueous solution of about 0.5 v / v% for about 3 minutes). The semiconductor substrate 1 dipped in the hydrofluoric acid solution has the structure shown in FIG.
As shown in the schematic view in (c), the insulating film 3 formed on the upper surface of the insulating film 3 is slightly etched, and the insulating film 3 under the gold layer 4 is eroded. The gold layer 4 is slightly floated, and the adhesion force of only the gold layer 4 formed on the insulating film 3 is further reduced, and the gold layer 4 is easily peeled off. At this time, the gold layer 4 is hardly affected because the hydrofluoric acid solution has a relatively low concentration.

(C) Then, the semiconductor substrate 1 thus treated is washed with water, and as shown in FIG. 1 (d), only the gold layer 4 on the insulating film 3 is peeled and removed to form a predetermined pattern. The electrode wiring layer of is formed. In the present invention, if the above-mentioned water washing is performed using ultrasonic waves, the water washing time can be shortened, which is more effective.

Although the above-mentioned embodiment shows the case where the gold layer is used as the metal layer, the present invention is not limited to this, and a metal which is not etched at all by a hydrofluoric acid solution or an etching rate for a hydrofluoric acid solution is insulated. Any metal that is as low as about 1/20 or less of the etching rate of the film can be used as the metal layer.

[0015]

According to the present invention, the electrode wiring layer can be formed without the need for the steps of forming the photoresist film, patterning, and removing, as compared with the prior art, and the manufacturing steps can be further reduced.

Since the hydrofluoric acid solution is used at a low concentration,
Unlike conventional etching solutions, special solutions such as organic solvents, work safety can be improved, and solution management becomes easier.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a manufacturing process of an example.

FIG. 2 is an explanatory diagram showing a conventional manufacturing process.

[Explanation of symbols]

 1 semiconductor substrate 2 window hole 3 insulating film 4 gold layer

Claims (1)

[Claims] 1. A step of forming a metal layer on a semiconductor substrate on which an insulating film having a window hole is formed, and a step of immersing the semiconductor substrate on which the metal layer is formed in a hydrofluoric acid solution. And (c) a method of manufacturing a semiconductor device, which comprises a step of washing the semiconductor substrate immersed in the hydrofluoric acid solution with water.