JPH0513409A - Manufacture of semiconductor device - Google Patents

Abstract

(57) [Summary] [Object] It is an object of the present invention to provide a method of manufacturing a semiconductor device, which can easily process a processed layer containing Au as a main material component without causing burrs. To do. [Structure] A Ti layer 13 is formed to a predetermined thickness on a wiring layer 12 layer containing Au as a main material component. A resist layer 14 is formed on the Ti layer 13, and the resist layer 14 is patterned. This patterned resist layer 1
The Ti layer 13 is selectively removed by the RIE method using 4 as a mask. The patterned resist layer 14 is removed, and the wiring layer 12 is selectively removed by the ion milling method using the exposed Ti layer 13 as a mask.

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 having a step of patterning a layer to be processed by an ion milling method.

[0002]

2. Description of the Related Art Conventionally, such an ion milling method has been used.
For example, it is used for patterning a wiring layer using an Au-based material in the manufacture of ICs such as compound semiconductors. FIG. 2 shows a wiring forming process using this ion milling method.

A wiring layer 2 containing Au as a main component is formed on the insulating film 1 (see FIG. 2A), and a resist layer 3 is further formed directly on the wiring layer 2 and patterned (the same). See FIG. (B)). Next, the wiring layer 2 is patterned by etching by the ion milling method using the resist layer 3 as a mask (see FIG. 7C). This ion milling method is to process the wiring layer 2 by a physical sputtering effect. After that, the resist layer 3 is removed to obtain the patterned wiring layer 2 and the wiring formation is completed (see FIG. 3D).

[0004]

However, in the above-mentioned conventional wiring forming method, during the patterning of the wiring layer 2 using the resist layer 3 as a mask, the Au particles scattered from the wiring layer 2 by the ion milling are resisted. It will redeposit on the sidewalls of layer 3. Therefore, when the resist layer 3 is removed after the patterning of the wiring layer 2 is completed, the Au particles redeposited on the sidewalls of the resist layer 3 remain as burrs 2a (see FIG. 2D). Therefore, even if the next wiring layer is formed on the patterned wiring layer 2 via the insulating film, the burr 2a causes a leak between the wirings.

If the resist layer 3 is thinly formed, it becomes difficult for Au particles to redeposit on the side wall of the resist layer 3.
It is possible to reduce the occurrence of a. But Au
In order to obtain the wiring layer 2 having a normal thickness of about 1 μm, the resist layer 3 has a thickness of 5000 when the wiring layer 2 containing particles as a main component and the resist layer 3 have the respective milling resistances. There was a situation where it was not practically possible to make it less than Angstrom.

[0006]

The present invention has been made in order to solve such a problem, and forms a Ti layer with a predetermined thickness on a layer to be processed whose main component is Au. And a second step of forming a resist layer on the Ti layer and patterning the resist layer, and using the patterned resist layer as a mask, the Ti layer is selectively subjected to reactive ion etching. Manufacturing a semiconductor device including a third step of removing the patterned resist layer and a fourth step of selectively removing the layer to be processed by an ion milling method using the exposed Ti layer as a mask To do.

[0007]

The Ti layer is formed to have a predetermined thickness that is sufficiently smaller than the thickness of the layer to be processed in consideration of the milling resistance of the layer to be processed, and is formed in the same pattern shape as the resist layer. Since the thin Ti layer is used as a mask and the layer to be processed is subjected to ion milling, particles scattered from the layer to be processed are less likely to be reattached to the sidewall of the thin Ti layer. Further, since the Ti layer is also shaved by the ion milling of the layer to be processed, even if the scattered particles are reattached to the side wall of the Ti layer, they are simultaneously removed by the ion milling.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a process sectional view showing a wiring forming method according to an embodiment of the present invention.
Various semiconductor devices including aAsIC are manufactured.

First, a Ti layer is formed to a thickness of 500 angstroms on the insulating film 11, and an Au layer is further formed to a thickness of 4500 to 9500 angstroms on the Ti layer. The wiring layer 1 includes the Ti layer and the Au layer.
2 is formed, and as a result, the wiring layer 12 becomes a layer containing Au as a main material component and having a thickness of 5000 to 10000 angstroms. Then, a Ti layer 13 having a thickness of about 2000 Å is formed on the entire surface of the wafer on the wiring layer 12 (see FIG. 1A). The thickness of the Ti layer 13 is set to about 1/5 of the maximum thickness of the wiring layer 12, and is 1/5 or more of the minimum thickness of the wiring layer 12.

Next, a photoresist is applied to the Ti layer 13 to a thickness of 1.3 μm, and this is patterned into a predetermined wiring shape to form a resist layer 14 (see FIG. 2B).

Next, the Ti layer 13 is selectively removed by reactive ion etching (RIE) using the resist layer 14 as a mask, and the Ti layer 13 has a pattern shape similar to that of the resist layer 14 (see FIG. See c)). Ti reacts with an F-based gas to form TiF ₄ , which easily sublimes. Therefore, an F-based gas such as CF ₄ or SF ₆ is used for this RIE processing. Further, since the Au-based material is chemically extremely stable to the F-based gas, the underlying wiring layer 12 is not affected by the RIE processing at all. Also,
Similarly to this, the resist layer 14 is not affected by the RIE processing, and the resist layer 14 is not deformed by the RIE processing.

Next, the resist layer 14 is removed to remove Ti.
The layer 13 is exposed (see FIG. 7D). The removal of the resist layer 14 is performed by wet etching using an organic solvent or dry etching using O ₂ gas.

Next, the wiring layer 12 is selectively removed by ion milling using the exposed Ti layer 13 as a mask. In this ion milling, only the Au layer of the wiring layer 12 is removed, and the Ti layer of the wiring layer 12 remains thin on the insulating film 11. Therefore, the wiring layer 1
Ti layer 13 and insulating film 11 left as a mask on 2
The remaining Ti layer is removed by the RIE method similar to the above. As a result, the wiring layer 12 having the same pattern shape as the pattern shape of the Ti layer 13 serving as the mask becomes the insulating film 1.
1 (see (e) in the figure), the wiring formation is completed.

According to this embodiment, as described above, the Ti layer 13 is formed to be sufficiently thinner than the wiring layer 12 in consideration of the milling resistance of the wiring layer 12. In other words, Au is 1000 angstroms per minute, T
For i, a layer having a thickness of 150 angstroms per minute was removed by ion milling, and the milling resistance of Ti was 5 that of Au.
It is more than twice as resistant. Therefore, the Ti layer 13 is Au
If the thickness of the wiring layer 12 made of a system material is set to 1/5 or more, the Ti layer 13 can function as an etching mask until the ion milling of the wiring layer 12 is completely completed. That is, since the wiring layer 12 is ion-milled using the thin Ti layer 13 having the same pattern as the resist layer 14 as a mask, Au particles scattered from the wiring layer 12 are redeposited on the sidewalls of the thin Ti layer 13. It becomes difficult. Further, since the Ti layer 13 is also slightly scraped by the ion milling of the wiring layer 12, even if the scattered particles are reattached to the side wall of the Ti layer 13, they are simultaneously removed by the ion milling. As a result, no burr is generated on the wiring layer 12.

As described above, according to this embodiment, it becomes possible to easily form the pattern of the wiring layer 12 made of the Au-based material, which is said to be difficult to process, without causing burrs.

[0016]

As described above, according to the present invention, the particles scattered from the layer to be processed are less likely to be redeposited on the side wall of the thin Ti layer which serves as a mask for ion milling. Further, since the Ti layer is also scraped by ion milling of the layer to be processed,
Even if the scattered particles reattach to the side wall of the Ti layer,
This ion milling removes them simultaneously.

Therefore, it becomes possible to easily process the layer to be processed made of the Au-based material without causing burrs.
Further, the conventional problem of inter-wiring leakage is solved.

[Brief description of drawings]

FIG. 1 is a process cross-sectional view showing a method of manufacturing a semiconductor device using a wiring forming method according to an embodiment of the present invention.

FIG. 2 is a process sectional view showing a method of manufacturing a semiconductor device using a conventional wiring forming method.

[Explanation of symbols]

 11 ... Insulating film 12 ... Wiring layer 13 ... Ti layer 14 ... Resist layer

Claims (1)

Claim: What is claimed is: 1. A first step of forming a Ti layer having a predetermined thickness on a layer to be processed containing Au as a main material component, and forming a resist layer on the Ti layer. A second step of patterning the resist layer, a third step of selectively removing the Ti layer by a reactive ion etching method using the patterned resist layer as a mask, and the patterned resist Exposed Ti by removing the layer
A fourth step of selectively removing the layer to be processed by an ion milling method using the layer as a mask.