JPS60254733A - Pattern forming method - Google Patents

Abstract

PURPOSE:To form a metal electrode having a minute structure, by making a semiconductor, which is grown on the side wall of an insulating film pattern, remain, and forming a resist pattern with the remaining semiconductor film as a mask. CONSTITUTION:A semiconductor film, e.g., a polysilicon film 6, is uniformly grown on a patterned insulating film, e.g., an SiO2 film 5, by using a CVD method. Then the polysilicon film 6 is etched by anisotropic plasma etching by Freon gas until the SiO2 film 5 is exposed. Thereafter, the SiO2 film 5 is removed by fluoric acid and the like. The polysilicon film 6 only on the side wall of the SiO2 film 5 is made to remain. A resist film 12 is applied so that a part of the remaining polysilicon film 6 is exposed. Thereafter, the polysilicon film 6 is removed by mixed acid and the like. Finally, a metal film 14 is evaporated on the entire surface and formed by sputtering and the like. The remaining resist film 12 is dissolved by an exfoliating agent such as an organic solvent and removed. The metal film 14 on the resist film 12 is removed.

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 forming a desired electrode pattern by a seven-off process.

(Prior Art) Conventionally, in a method of manufacturing a semiconductor device, a method of forming an electrode pattern by a lift-off process has been adopted.

For example, as shown in FIG. 1(a), a resist 2 is applied on a substrate 1 such as GaAsJp8i, exposed and developed using a predetermined mask, and windows 3 in a predetermined pattern are formed.
Next, as shown in Φ) in the same figure, At was applied to the entire surface.

A required metal film 4 such as Au or T I is formed by vapor deposition, sputtering, or the like. Thereafter, as shown in FIG. 3(C), when the remaining resist 2 is dissolved and removed using a stripping agent such as an organic solvent, the metal film 4' on the resist 2 is released from the substrate 1, and the metal film 4 formed on the window 3 is removed. Only board 1
remain on top. As a result, a metal film 4 having a predetermined pattern can be formed on the substrate 1, as shown in FIG. 1D.

In recent years, in order to improve the characteristics of semiconductor devices, for example, GaAs
In ME8PET (field effect transistor using a metal-semiconductor junction as a gate electrode), miniaturization has progressed such that the gate length of the gate electrode is required to be 0.3 μm or less. However, it is extremely difficult to form patterns of 0.3 μm or less using conventional ultraviolet exposure methods, and electron beam exposure methods, which are said to be suitable for forming fine patterns, have extremely poor mass productivity. There is.

Therefore, a method that can form metal patterns of 0.3 μm or less with high efficiency and high yield is desired.

(Problems to be Solved by the Invention) The present invention has been made in view of the above points, and its purpose is to provide a method for forming a metal electrode having the above-mentioned microstructure.

(Means for Solving the Problems) According to the present invention, an insulating film is formed on a substrate, a semiconductor is formed on the entire surface of the insulating film including the side surfaces, and the semiconductor is removed by anisotropic etching to insulate the insulating film. Leaving only the semiconductor on the side of the membrane,
Thereafter, a pattern forming method is obtained in which the insulating film is removed, a resist is formed in a region other than the remaining semiconductor, the semiconductor is removed, a metal layer is formed on the entire surface, and the metal layer on the resist is removed together with the resist.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings. .

FIG. 2 is a process sectional view of an embodiment of the present invention, which is for forming a metal film pattern on a substrate.

First, as shown in FIG. 2(a), a semiconductor film such as a polysilicon film 6 is uniformly grown on a patterned insulating film, such as a 5i (h film 5), using the CVD method.
The polysilicon film 6 is grown on the sidewall of the i02 film 5 in order to obtain a desired resist pattern shape, as will be described later. For example, when forming a gate electrode with a gate length of 0.2 μm, a polysilicon film 6 with a thickness of 0.2 μm is deposited on the entire surface so as to grow on the side walls.

Next, as shown in FIG. 2), the polysilicon film 6 is etched by anisotropic plasma etching using Freon (CF4) gas until the 8i0z film 5 is exposed. At this time, the polysilicon film 6 grown on the side wall of the Sing film 5 remains without being etched because there is no lateral etching component in the anisotropic plasma etching.

Thereafter, as shown in FIG. 2C, the Si02 film 5 is removed using hydrofluoric acid or the like, leaving only the polysilicon film 6 on the sidewalls of the 5iOz film 5.

Next, as shown in FIG. 2(d), a resist 12 is applied so that a portion of the remaining polysilicon film 6 is exposed. After that, as shown in FIG. 2(e), the polysilicon film 6
is removed with a mixed acid (for example, a mixture of hydrofluoric acid, nitric acid, and glacial acetic acid).

Finally, as shown in FIG. 2(f), a metal film 14 is formed on the entire surface by vapor deposition, sputtering, etc., and the remaining resist 12 is dissolved and removed using a stripping agent such as an organic solvent, and the metal film 14 on the resist 12 is removed. do.

According to this manufacturing method, the pattern formation of the resist 12 is 8
It is made by using the polysilicon film 6 grown on the sidewall of the i02 film 5, and does not require the conventional processes such as exposure and lithography. Therefore, fine patterns can be reliably formed by appropriately selecting the thickness of the semiconductor film grown on the sidewalls.

As explained above, the present invention is a conventional method in which a semiconductor film grown on the sidewall of an insulating film pattern is left and a resist pattern is formed using the remaining semiconductor film as a mask. This method has the advantage that extremely fine patterns can be formed with high yield without using processes such as exposure and lithography.

[Brief explanation of drawings]

FIGS. 1(a) to 1(d) are sectional views showing a conventional lift-off process, and FIGS. 2(a) to 2(f) are sectional views showing a process according to an embodiment of the present invention. 1.11... Semiconductor substrate, 2.12...
・Resist, 4.14...Metal film, 5...
...Insulating film, 6...Semiconductor film 3゜82Figure 20

Claims (1)

[Claims] A step of forming an insulating film pattern on a substrate and covering the insulating film with a semiconductor film, a step of leaving only the semiconductor film grown on the sidewall of the insulating film and removing other semiconductor films, and a step of removing the remaining semiconductor film. A step of forming a resist pattern using a film as a mask, a step of forming a metal film on the surface of the resist pattern, and a step of removing the metal film on the resist together with the resist to leave a metal film between the resists. A pattern forming method characterized by comprising: