JPS62272540A - Manufacture of semiconductor - Google Patents

Abstract

PURPOSE:To improve a boundary state from a thin film formed in later steps by substituting etching gas for gas containing hydrogen after etching step with gas, and then forming a thin film, such as an insulating film, a semiconductor film or a metal film. CONSTITUTION:After a wafer is placed on a tray 3, inner air is evacuated, and chlorine gas (Cl2) from a gas box 7 is fed into a chamber. Then, an ultraviolet ray is generated from a light source 5, and emitted by a reflecting mirror 6 to the surface of the wafer 2. The chlorine gas partly becomes radical by the energy of the ultraviolet ray to etch a single crystal silicon on the wafer 2 to dry clean it. Then, the chlorine gas is exhausted, and hydrogen gas is fed into the chamber 1, and substituted for a hydrogen gas atmosphere in the chamber. Thus, the end group of the Si substrate becomes H atoms. Then, after H2 gas is exhausted, the O2 gas is fed from the box 7 into the chamber 1. The wafer 2 is then heated by a heater 4 to form an oxide film on the wafer 2.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Summary] The method for manufacturing a semiconductor device of the present invention includes replacing the etching gas with a hydrogen-containing gas after the gas etching step, and then replacing the etching gas with a hydrogen-containing gas. It is characterized by forming a thin film such as an insulating film, a semiconductor film, or a metal film. By forming a predetermined thin film after the terminal groups on the surface of the semiconductor device are replaced with hydrogen atoms, it becomes possible to form an Ij film with better quality.

[Industrial application field]

The present invention relates to a method for manufacturing a semiconductor device, and more specifically, to a method for surface treatment of a semiconductor device before forming a thin film.

[Conventional technology]

Conventionally, as a post-treatment after gas etching, cleaning with running water is generally performed in order to remove adsorption groups formed on the surface by atoms of the gas.

[Problem that the invention seeks to solve]

By the way, according to conventional washing with running water, even if the above-mentioned adsorption groups can be removed, the surface is still covered with water molecules.

Therefore, when a thin film such as an insulating film, a semiconductor film, or a metal film is subsequently formed on a semiconductor device, there is a problem that the interface state between them becomes unstable.

In particular, if impurity substances remain in the water, they will be contaminated and the interfacial state will become more unstable.

In addition, there is a problem in that the dry process is broken by this washing with running water, which makes the process complicated.

The present invention was created in view of such conventional problems, and aims to provide a method for manufacturing a semiconductor device that makes it possible to improve the interface state with a thin film formed in a later process. .

[Means for solving problems]

In the method for manufacturing a semiconductor device of the present invention, after the etching step using a gas, the etching gas is replaced with a gas containing hydrogen, and then the gi1! f! It is characterized by the formation of

[Effect]

After gas etching, the gas is replaced with an atmosphere containing hydrogen gas, so that the terminal groups on the surface of the semiconductor device become hydrogen atoms.

Next, when a thin film is formed on the semiconductor device, a thin film with a good interface state is formed due to the presence of the hydrogen.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram for explaining a method of manufacturing a semiconductor device according to an embodiment of the present invention, and ▪ indicates a chamber. 2
is a wafer placed on the storage table 3, and 4 is a heater. 5 is a light source that emits ultraviolet rays; 6 is a reflecting mirror for guiding the ultraviolet rays into the chamber 1; Also 7
is a gas box, 5iHa gas, 02 gas, C1
Two gases can be selected to flow into the chamber 1.

First, after placing a wafer on the JtLN stand 3 in the chamber 1, the air inside is exhausted, and chlorine gas (C1z) is flowed into the chamber from the gas box 7.

Next, a light source 5 generates ultraviolet rays, and a reflecting mirror 6 irradiates the surface of the wafer 2 with the ultraviolet rays. Dry cleaning is performed by partially converting the chlorine gas into radicals due to the energy of ultraviolet rays and etching the single layer silicon on the surface of the wafer 2. At the end of this dry run, the surface of the wafer 2 is as shown in FIG. 2(a).
A C1 atom is adsorbed or chemically bonded to a Sl atom.

Next, chlorine gas is exhausted and hydrogen gas is
<-1 to replace the inside of the chamber with a hydrogen gas atmosphere. As a result, the 0M atoms on the surface of the St substrate immediately react with H2 and are taken out (second
Figure (b)), the exposed surface instantly becomes H2
The terminal groups on the surface of the S1 substrate become HIK molecules (Fig. 2(c)).

Next, after exhausting the H2 gas, the gas box 7 is
2 gases are allowed to flow into chamber 1. and heater 4
By heating the wafer 2, an oxide film is formed on the surface of the wafer 2.

As described above, the embodiment method of the present invention cleans the substrate surface with radical chlorine, further replaces the C1 atom terminal group with the H atom terminal group, and then forms an oxide film.
The interface state between the oxide film and the silicon substrate can be made stable.

According to experiments conducted by the present inventors, the density of interface states of the oxide film formed by the method of the embodiment of the present invention was 173 times lower than that of the oxide film formed after cleaning by ordinary solution cleaning.

Although the example describes the case of forming an oxide film on a silicon substrate, it is also applicable to forming other insulating films, semiconductor films, and metal films (for example, using SiH4 gas instead of 02 gas in a gas box). 7, a silicon epitaxial layer with good W2 quality can be obtained.)

In addition to ultraviolet rays, charged particle irradiation such as ions and plasma may be used to convert halogen into a radical state.Although chlorine gas is used as the halogen gas, other halogen gases may also be used. Of course.

〔Effect of the invention〕

As explained above, according to the present invention, the surface of a semiconductor device after gas etching can be cleaned by a simple dry treatment. This makes it possible to form an 8I film with good film quality.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining a manufacturing method according to an embodiment of the present invention, and FIG. 2 is a diagram for explaining the atomic bonding state on the surface of a silicon substrate in each step of the manufacturing method according to an embodiment of the present invention. be. (Explanation of symbols) 1...Chamber. 2...Wafer, 3...Kuragodai. 4...Heater, 5...Light source, 6...Reflector. 7... Gas box, 7.
1″Near 7th mirror ≦”1
No.) Figure 1

Claims (1)

[Claims] 1. A method of manufacturing a semiconductor device, which comprises replacing the etching gas with a hydrogen-containing gas after an etching step using a gas, and then forming a thin film such as an insulating film, a semiconductor film, or a metal film.