JPH05175192A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To strengthen adhesiveness between a substrate and a metal layer so as to perform patterning by ion etching in relation to formation of a wiring to be provided on an insulating substrate. CONSTITUTION:The manufacture includes a process of piling up a silicon layer 2 consisting either of amorphous silicon and polycrystalline silicon on the surface of an insulating substrate 1, a process of piling up a conductive layer 3 on the surface of the silicon layer 2 and a process forming a wiring pattern 6 by simultaneously and selectively performing ion etching on the metal layer 3 and the silicon layer 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for forming a wiring whose surface is provided on a substrate made of an insulating material.

In an active matrix type liquid crystal display device, a thin film transistor for driving a liquid crystal is formed on an insulating substrate made of an insulating material or the surface of which is covered with an insulating layer, and wiring for connecting each element is formed on the surface of the insulating substrate. It is manufactured by depositing a conductive metal layer and patterning it to form a wiring pattern.

It is desirable that such wiring is made of a material having a small specific resistance and has high reliability. Therefore, there is a need for a method of manufacturing a semiconductor device that can easily form highly reliable wiring on an insulating substrate using a metal having a low specific resistance.

[0004]

2. Description of the Related Art FIG. 2 is a process diagram of an embodiment of a conventional method, and is a sectional view showing a process of forming a wiring pattern on an insulating substrate in a manufacturing process of a liquid crystal display device. Elements that are not directly involved in the manufacture of the wiring pattern are omitted in FIG.

A conventional technique will be described with reference to FIG.
2A and 2B, the conventional technique first cleans the insulating substrate 1 made of glass, and sputters aluminum on one surface of the insulating substrate 1 to deposit the metal layer 3.

Next, referring to FIG. 2C, a titanium layer 4 is deposited by sputtering. Next, referring to FIG. 2D, a resist pattern 5 is formed on the titanium layer 4 by photolithography.

Next, referring to FIG. 2E, the titanium layer 4 is patterned by ion etching using the resist pattern 5 as a mask. Next, referring to FIG. 2D, the metal layer 3 is wet-etched using the titanium layer 4 as a mask to form a wiring pattern 6 in which the metal layer 3 and the titanium layer 4 are overlaid on the insulating substrate 1. To be done.

However, whiskers grow on the surface when ion-etching the aluminum layer and impair the flatness of the surface. Therefore, in such a conventional wiring forming method, the ion-etching method is applied to the etching of the metal layer 3 made of aluminum. Can not do it. Therefore, the titanium layer 4
It is necessary to separately perform the ion etching and the wet etching of the metal layer 3 in two steps, which increases the number of manufacturing steps and complicates them. Further, it is difficult to perform precise patterning by wet etching.

The titanium layer 4 provided on the aluminum is provided for the purpose of enhancing the breaking strength of the aluminum pattern because the aluminum has poor adhesion to the insulating substrate 1 and easily peels off and breaks. Therefore, in the conventional aluminum wiring, the titanium layer cannot be omitted from the viewpoint of reliability. Therefore, the two etching steps of the aluminum layer and the titanium layer are indispensable.

[0010]

As described above, in the conventional method for manufacturing a semiconductor device in which a metal layer is deposited on an insulating substrate and is formed into a wiring pattern by etching, the adhesion between the substrate and the metal layer is poor. Therefore, reinforcement with a titanium layer is required. However, since the metal layer cannot be ion-etched, the metal layer must be etched by wet etching. For this reason, the ion etching of the titanium layer has to be performed in a separate step from the wet etching of the metal layer, which has the drawback that the number of steps becomes complicated.

Further, there is a drawback that the metal layer cannot be precisely patterned by wet etching. In addition, the weak adhesion between the substrate and the metal layer causes a problem of impairing the reliability of the semiconductor device.

The present invention enables ion etching of the metal layer by strengthening the adhesion between the surface of the insulating substrate and the metal layer, thereby improving the reliability of the wiring and
It is an object of the present invention to provide a method for manufacturing a semiconductor device, which can precisely pattern a metal layer by one-time ion etching.

[0013]

FIG. 1 is a process chart of an embodiment of the present invention, which is a sectional view showing a process of forming a wiring pattern on an insulating substrate. Elements that are not directly involved in the manufacture of the wiring pattern are omitted in FIG.

In order to solve the above-mentioned problems, the first structure of the present invention is as follows. Referring to FIG. 1, a silicon layer 2 made of either amorphous silicon or polycrystalline silicon is formed on the surface of an insulating substrate 1. And a step of depositing a conductive metal layer 3 on the surface of the silicon layer 2, and a step of selectively ion-etching the metal layer 3 and the silicon layer 2 simultaneously to form a wiring pattern 6. And the second structure is characterized in that, in the method for manufacturing a semiconductor device having the first structure, the metal layer 3 is made of aluminum.

[0015]

In the structure of the present invention, the metal layer to be the wiring pattern is deposited on the amorphous or polycrystalline silicon layer deposited on the insulating substrate.

It is known that the silicon layer deposited on the insulating substrate has strong adhesion, and the metal layer deposited on the silicon layer has good adhesion to the silicon layer. Therefore, according to the present invention, a highly reliable wiring pattern is formed.

Further, the inventor of the present invention has clarified that the metal layer deposited on the silicon layer of the present structure does not generate whiskers even if ion etching is performed.
Therefore, the metal layer can be ion-etched to form a wiring pattern. Therefore, since the wiring pattern can be formed by ion etching without using wet etching, precise patterning is performed.

The silicon layer or titanium layer can be easily ion-etched. Therefore, according to the present invention, the silicon layer and the metal layer, or the deposited layer formed by laminating the titanium layer on the silicon layer and the metal layer can be formed into the wiring pattern by one-time ion etching. Therefore, the manufacturing process is small and simple. It should be noted that such shortening of the steps contributes to the improvement of the reliability of the device, such as a transistor, which is previously manufactured on the insulating substrate.

It is considered by the inventor of the present invention that the metal layer and the silicon layer have a strong adhesive force in the present structure for the following reason. When the metal layer is deposited directly on the surface of the insulating substrate, the density of growth nuclei formed on the surface of the insulating substrate is low in the initial stage of depositing the metal layer. Therefore, the area of the interface forming a strong bond with the insulating substrate is small, and the adhesive force with the insulating substrate is weak. In addition, since the distance between adjacent growth nuclei is large, it is easy to adopt a columnar structure. Therefore, the atoms located at the grain boundaries easily move to the surface by the energy given by ion etching and grow whiskers.

On the other hand, since silicon has a large surface energy, the metal layer deposited on the surface of the silicon layer produces growth nuclei at a high density. Therefore, the adhesion with the insulating substrate is strong and the columnar structure is not formed, so that the growth of whiskers generated during ion etching is suppressed.

Therefore, according to the structure of the present invention, a wiring material having a low specific resistance, such as aluminum, can be deposited on the insulating substrate and ion-etched to form a wiring pattern. In addition, since a metal layer made of fine grains is deposited, there is an effect that it can be precisely etched.

[0022]

EXAMPLES The present invention will be described with reference to examples. Referring to FIG. 1A, the insulating substrate 1 is a glass substrate serving as a display portion of an active matrix type liquid crystal display device having elements such as transistors (not shown in FIG. 1) formed on the surface thereof. is there.

First, referring to FIG. 1B, the insulating substrate 1
An amorphous silicon layer is deposited on the surface of the substrate by, for example, plasma CVD (chemical vapor deposition) to a thickness of 5 nm. A polycrystalline silicon layer may be used instead of the amorphous silicon layer.

Next, referring to FIG. 1C, the metal layer 3
A 60 nm thick aluminum layer is deposited by sputtering. Deposition can also be by other commonly used methods.

Next, with reference to FIG. 1D, a titanium layer 4 is deposited by sputtering, for example, to a thickness of 40 nm. The titanium layer 4 strengthens and reinforces the breaking strength of aluminum and is not an essential requirement of the present invention, but it is preferably used for improving reliability.

Next, referring to FIG. 1E, a resist is applied on the titanium layer 4 and a resist pattern 5 is formed by photolithography. Next, referring to FIG. 1F, the titanium layer 4, the metal layer 3 and the silicon layer 2 are simultaneously patterned by ion etching using the resist pattern 5 as a mask to form a wiring pattern 6. The ion etching for forming this wiring pattern 6 is
For example, boron trichloride with a flow rate of 100cc / min and flow rate of 100cc / min
It can be performed by parallel plate type plasma etching in a mixed atmosphere with a chlorine pressure of 10 mToor.

In the present embodiment, even if the titanium layer 4 is provided for strengthening, the number of etching steps does not increase, and the reliability of the wiring can be improved without increasing the number of steps. In another embodiment of the present invention, referring to FIG. 1, the metal layer 3 is deposited on the silicon layer 1 and heat-treated to make the silicon layer 1 an alloy layer with the metal layer 3 in the above embodiment. .

Then, a wiring pattern is formed in the same manner. According to this embodiment, the adhesion between the metal layer and the insulating substrate can be made stronger and the reliability is improved.

[0029]

As described above, according to the present invention, a highly reliable wiring can be deposited on the surface of an insulating substrate because a metal layer that has adhesion and does not generate whiskers even when ion-etched is deposited. It is possible to provide a method for manufacturing a semiconductor device in which a pattern is formed by one-time ion etching, and this greatly contributes to improving the performance of the semiconductor device.

[Brief description of drawings]

FIG. 1 is a process chart of a first embodiment of the present invention.

FIG. 2 is a process chart of an example of a conventional method.

[Explanation of symbols]

 1 Insulating Substrate 2 Silicon Layer 3 Metal Layer 4 Titanium Layer 5 Resist Pattern 6 Wiring Pattern

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H01L 29/784

Claims (2)

[Claims] 1. A step of depositing a silicon layer (2) made of any one of amorphous silicon and polycrystalline silicon on the surface of an insulating substrate (1), and a conductive layer on the surface of the silicon layer (2). It has a step of depositing a metal layer (3) and a step of simultaneously selectively ion-etching the metal layer (3) and the silicon layer (2) to form a wiring pattern (6). Method of manufacturing semiconductor device. 2. The method of manufacturing a semiconductor device according to claim 1, wherein the metal layer (3) is made of aluminum.