JPH02185028A - Method of forming thin film - Google Patents

Abstract

PURPOSE:To form a thin film having an excellent step covering ratio by heating a semiconductor substrate at a temperature of 250 deg.C or more in an atmosphere in which an inert gas and a source gas are mixed. CONSTITUTION:A source-gas supply port 1c is shaped in parallel with the inert- gas supply port 1a of a film formation chamber 1. Argon gas is fed from the inert-gas supply port 1a and Al(CH3)3 gas as a radical source gas from the source-gas supply port 1c respectively, and the inside of the film formation chamber 1 is brought to a mixed gas atmosphere at fixed pressure while a semiconductor substrate 5 is heated at a temperature of 250 deg.C or more. High voltage is applied between a cathode 2 and an anode 4, and discharge is generated. Consequently, evaporation by sputtering and chemical vapor growth having no directional properties are generated simultaneously on the surface of the semiconductor substrate 5, and a thin film on the side face of a stepped section is shaped thickly. Accordingly, the this film having an excellent step covering ratio is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for forming a thin film used in manufacturing a semiconductor device.

(Prior Art) In recent years, sputtering, which is excellent in reproducibility, reliability, automation, and throughput, has been widely adopted as a method for forming thin films used in the manufacture of semiconductor devices.

A conventional method for forming this type of thin film will be explained with reference to FIG.

This figure is a configuration diagram showing the principle of sputtering. The sputtering film forming apparatus has a film forming chamber 1 provided with an inert gas supply port 1a and an exhaust port 1b, and a cathode 2 disposed above a target. A semiconductor substrate 5 is attached to the anode 3 and the anode 4 arranged below.

These are arranged so as to face each other.

In order to form a thin film on the surface of the semiconductor substrate 5 using the sputtering film forming apparatus configured in this way, first, after evacuating the film forming chamber l, argon gas is supplied from the inert gas supply port 1a. After creating an argon gas atmosphere at a constant pressure, the cathode 2
A high voltage is applied between the anode 4 and the anode 4 to cause discharge. The argon gas is decomposed into positive ions 6 and electrons 7, which are attracted to the target 3 connected to the cathode 2 and the semiconductor substrate 5 connected to the anode 4, respectively. The positive ions 6 having mass are accelerated and hit the target 3 at a high speed, and eject atoms 8. The ejected atoms 8 adhere to the surface of the semiconductor substrate 5 placed opposite to each other and form a thin film. .

(Problems to be Solved by the Invention) However, in the above configuration, since the atoms 8 have directionality in movement, a thin film formed on a pattern having a one-step difference becomes thinner on the side surfaces of the step.

There were problems in that the step coverage was poor, the yield was low, and the reliability was low.

The present invention solves the above problems and provides a method for forming a highly reliable thin film with good step coverage.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a method for heating a semiconductor substrate at a temperature of 25% in an atmosphere containing a mixture of an inert gas and a source gas.
The film is formed by heating to 0° C. or higher.

(Function) With the above configuration, vapor deposition by sputtering and non-directional chemical vapor phase growth occur simultaneously on the surface of the semiconductor substrate, forming a thick thin film on the side surface of the step, resulting in a thin film with good one-step coverage. be done.

(Example) An example of the present invention will be described with reference to FIGS. 1(a) and 1(b), taking a method of forming an aluminum alloy thin film as an example.

1v4(a) and (b) are a block diagram showing the principle of the thin film forming method according to the present invention and an enlarged cross-sectional view of the main parts thereof.

The film forming apparatus according to the present invention shown in FIG. 1(a) is different from the conventional example shown in FIG. Although not shown in Figure 1, there is a point where a heater for the semiconductor substrate 5 is provided. Since the rest is the same as the conventional example, the same components are given the same reference numerals and their explanations will be omitted.

In order to form an aluminum alloy thin film on the surface of the semiconductor substrate 5 using the film forming apparatus configured as described above, argon gas is supplied from the inert gas supply port 1a as a radical source gas A Q (CH,)3 Gases are supplied from the source gas supply ports IC to create a mixed gas atmosphere at a constant pressure inside the film forming chamber 1, while the semiconductor substrate 5 is heated to a temperature of 250° C. or higher. Next, when a high voltage is applied between the cathode 2 and the anode 4 to cause a discharge, the argon gas is decomposed and the cations 6
and electrons 7, while the AQ(CH,) gas becomes radical source gas molecules 9. Atoms 8 ejected from the target 3 by the positive ions 6 attracted by the cathode 2 and accelerated adhere to the surface of the semiconductor substrate 5 disposed opposite thereto. On the other hand, the source gas molecules 9 cause chemical vapor phase growth to form a thin film on the surface of the semiconductor substrate 5 maintained at a temperature of 250° C. or higher.

FIG. 1(b) shows PS formed on the surface of the semiconductor substrate 5.
This is an enlarged cross-sectional view of the main part showing the step part of the G film 10,
Since the atoms 8 produced by sputtering have directionality,
Although it is difficult to adhere to the stepped surface of the PSG film IO, since the source gas molecules 9 that cause chemical vapor deposition do not have directionality,
Since the film is formed on the step surface of PSGIIIO at the same growth rate as on the surface, the film thickness on one step surface can be increased.

As described above, according to this embodiment, since sputter deposition and chemical vapor deposition are performed simultaneously, a thin film with good step coverage can be formed.

In addition, in this example, A a (CH
Although z L was used, any gas such as A Q (Ci2.) that can produce an aluminum alloy film by chemical vapor deposition may be used.

Further, in this example, the formation of an aluminum alloy film was taken as an example, but it is also possible to form a thin film of a material that can be sputtered, such as tungsten, molybdenum, silicon dioxide, etc. However,
It goes without saying that the source gas used is one in which the main components of these thin films are produced by chemical vapor deposition.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are a block diagram showing the principle of the thin film forming method according to the present invention and an enlarged cross-sectional view of the main parts thereof, and FIG.
The figure is a block diagram showing the principle of a conventional thin film forming method. 1... Film forming chamber, 1a... Inert gas supply port,
lb...Exhaust port, 1c...Source gas supply port,
2...Cathode, 3...Target, 4...
Anode, 5... Semiconductor substrate, 6... Cation, 7
...electron, 8...atom, 9...source gas molecule, 10...psaHg, 11...aluminum alloy thin film.

Claims (1)

[Claims] Using a sputter film forming apparatus, the film forming chamber is made into a mixed gas atmosphere of an inert gas for sputtering and a source gas for chemical vapor deposition, and the semiconductor substrate of the anode is heated to a temperature of 250°C.
A method for forming a thin film, which is characterized by heating the film to a temperature above ℃ and performing film formation by chemical vapor deposition simultaneously with sputtering film formation.