JPH02164033A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To reduce dry-etching damage by incorporating an AlN thin film intermediate layer as a mask in dry-etching. CONSTITUTION:An AlN thin film 4 (GaAs) substrate 1 by gallium arsenide (GaAs) substrate 1 by reactive sputtering, and then a photoresist film 3 for processing of the AlN film 4 is formed and irradiated with ultraviolet rays. Then, development (removal of the photoresist 3) is carried out with a proper alkaline solution. Thereupon, the AlN film 4 is soluble to the alkaline solution, so that the AlN thin film 4 can simultaneously be removed. Further, with use of the photoresist mask 3 and the AlN thin film 45 as masks, reactive ion etching is carried out using SiCl4 gas to form a vertical groove 5 in the GaAs substrate 1. The AlN film 4 is highly resistant to dry-etching, and hence can be processed into a desired size. Dry-etching damage such as contamination by carbon can be reduced, permitting excellent processing in transfer accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a method of processing semiconductor substrates, metals, etc. using dry etching.

[Prior Art 1] FIGS. 4 to 7 are device cross-sectional views showing each step of a conventional method for processing a GaAs substrate 1 by dry etching.

In this conventional example, first, a Ni (nickel), Ti (titanium), or W (tungsten) layer 2 is formed as an intermediate layer on a GaAs substrate 1, then a photoresist 3 is formed, and a predetermined portion is exposed to ultraviolet rays. Irradiate (Fig. 4) Next, remove the photoresist 3 in the area irradiated with ultraviolet rays (Fig. 4).
Figure 5) Next, using the photoresist 3 as a mask, N1 (
Next, using the Ni (Ti, W) layer 2 as a mask, the GaAs substrate 1 is removed by reactive ion etching (RIE).
is etched (Figure 7).

[Problem to be solved by the invention]

In the conventional semiconductor device manufacturing method described above, when a strong acid such as H (wet process) is used when etching the intermediate layer 2 made of Ni or the like, the photoresist film may peel off, and the wet etching conditions are not suitable. Further, side etching occurs, causing problems in dimensional controllability.

Also, due to the dry process, intermediate! After processing 2,
The conventional method described above has a problem in that the process used to process this intermediate layer cannot be used as is when processing GaAs, an insulating film, etc., and the processes for processing are limited.

[Means for Solving the Problems j] The method for manufacturing a semiconductor device of the present invention includes forming an aluminum nitride thin film on a workpiece, selectively removing a portion of the aluminum nitride thin film, and then removing the remaining aluminum nitride thin film. Using the aluminum nitride thin film as a mask, the object to be processed is etched by dry etching.

[Effect]

Since the dry etching resistance of aluminum nitride (AI2N) film is sufficiently high regardless of the gas used, for example, S F
a , S I Fa , B F 4 , S I
CA a.

Gases such as B CA a can be used, which allows carbon (C
) Dry etching damage such as contamination is extremely reduced, allowing processing with excellent transfer accuracy. Furthermore, Aβ
Since the N pattern formation can be carried out simultaneously with the development of the upper layer photoresist, it is simple and has excellent controllability.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

1 to 3 are process cross-sectional views showing one embodiment of the method for manufacturing a semiconductor device of the present invention.

First, an IIN thin film 4 is grown on a gallium arsenide (GaAs) substrate 1 by reactive sputtering, and then an AβN
114 A photoresist film 3 for processing is formed and irradiated with ultraviolet rays (Fig. 1).Next, development is performed with an appropriate alkaline solution (removal of the photoresist 3), but at this time AβNll14 is easily exposed to the alkaline solution. Since it is a solution, this AρNff14 can also be removed at the same time (Fig. 2).
Using the photoresist mask 3 and the Aj2NI2N thin film mask, reactive ion etching is performed using S i CA a gas (FIG. 3) to form a vertical groove 5 in the GaAs substrate l. At this time, since the AβN film has sufficiently high dry etching resistance, it can be processed to desired dimensions.

In the above-described embodiment, a case where a GaAs substrate is etched has been described, but the etching process is not limited thereto, and the target to be processed is, for example, SiQ.

It may also be a film or the like.

When processing SiO2 film using AJ2N intermediate thin film,
Since AJ2N film has high dry etching resistance, CF4
and CHF, other than (7) S Fa, S i F 4
5in2 film processing is possible even with a gas such as BF2, thereby significantly reducing dry etching damage caused by carbon (C) contamination and the like.

[Effects of the Invention] As explained above, the present invention uses the AβNTIJ film intermediate layer as a mask during dry etching processing, resulting in very little dry etching damage, excellent transfer precision, and excellent simplicity and controllability. This has the effect of providing a processing method.

[Brief explanation of the drawing]

1 to 3 are process cross-sectional views showing one embodiment of the method for manufacturing a semiconductor device of the present invention. FIG. 1 is a cross-sectional view after forming an A48M and photoresist film, and FIG. 3 is a sectional view after processing a GaAs substrate by reactive ion etching, and FIGS. 4 to 7 are process sectional views showing a conventional example. 1...GaAs substrate, 3...Photoresist, 4-A I2N thin film, 5...Groove.

Claims (1)

[Claims] 1. When processing semiconductor substrates, insulators, metals, etc. by dry etching, an aluminum nitride thin film is formed on the workpiece, a part of the aluminum nitride thin film is selectively removed, and then the remaining aluminum nitride thin film is removed. A method for manufacturing a semiconductor device, in which the target is etched by dry etching using an aluminum nitride thin film as a mask.