JPH0590250A - Method of treating wafer - Google Patents

Abstract

PURPOSE:To make it possible to form a homogeneous oxide film using silane- oxygen gas by an LP-CVD method which is one of methods of treating a wafer. CONSTITUTION:An oxide film 3 is formed on the surface of a wafer 1 on the oxide film formation conditions that diethylsilane gas or oxygen gas is used as oxidizing gas and an atmospheric temperature, a pressure, the flow rate of diethysilane and the flow rate of oxygen are respectively set at 350 to 450 deg.C, 70 to 100 Pa, 40 to 80cc/min and 60 to 120cc/min.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer processing method for forming an oxide film on the surface of a wafer, which is one of the manufacturing steps of semiconductor devices.

[0002]

2. Description of the Related Art As one method for forming an oxide film on the surface of a wafer, there is a low temperature oxide film forming method for forming an oxide film on a wafer surface at a relatively low temperature using a silane-oxygen based gas.

Another method for surface treatment of wafers is LP-
CVD (Low Pressure Chemical
There is a Vapor Deposition) method. This LP-CVD method is known as a processing method having excellent mass productivity, and polysilicon, a nitride film, etc. are formed on the surface of a wafer.

[0004]

As described above, the LP-
Although the CVD method is excellent in mass productivity as a wafer processing method, it has not been conventionally used in the above-described low temperature oxide film forming method. In the LP-CVD method, this is silane-
This is because when a low temperature oxide film is formed using an oxygen-based gas, there is a problem in film quality such as film thickness uniformity.

In view of such circumstances, the present invention is LP-CVD.
In the method, a silane-oxygen based gas is used so that a homogeneous oxide film can be formed to improve productivity.

[0006]

The present invention is characterized in that diethylsilane and oxygen are used as an oxidizing gas to form an oxide film on the wafer surface.

[0007]

The oxide film forming condition is, for example, an ambient temperature of 350.
℃ ~ 450 ℃, pressure 70Pa ~ 100Pa, diethylsilane flow rate 40cc / min ~ 80cc / min, oxygen flow rate 60cc / min
~ 120cc / min

[0008]

EXAMPLES Examples of the present invention will be described below.

In the LP-CVD method, the present inventors have
Regarding the oxide film when a low-temperature oxide film was formed using a silane-oxygen gas, various experiments were conducted with the belief that a practical oxide film could be obtained by limiting the production conditions, and as a result, it was found to be practical. It is possible to specify the appropriate conditions for forming an oxide film.

A vertical LP-CVD apparatus was used as an experimental apparatus for obtaining the above-mentioned suitable conditions, and a 6-inch wafer was selected as an experimental wafer.

Further, 40 wafers were set as a process area of the LP-CVD apparatus, and a total of 7 dummy wafers were loaded on the upper and lower sides. Further, diethylsilane and oxygen are used as the gas to be supplied to the oxidation reaction, and the supply flow rate is controlled by a generally used MFC (Mass Flow Controller).
oler).

As a result of producing an oxide film under various production conditions, a practically suitable oxide film is produced under the following conditions: temperature: 350 ° C. to 450 ° C. pressure: 70 Pa to 100 Pa Gas flow rate: diethylsilane 40 cc / min to 80 cc / min: Oxygen of 60 cc / min to 120 cc / min was obtained.

Further, with regard to the uniformity of the film thickness, a film thickness distribution of ± 5% was obtained by appropriately selecting the furnace internal structure.

The produced film according to this embodiment also has excellent step coverage, and TEOS (T) which is said to have excellent step coverage.
The quality of the oxide film was not significantly different from that of the oxide film using the etraethyl orthosilicate as a raw material, and the film quality was significantly improved as compared with the oxide film formed using a silane-oxygen-based gas at normal pressure.

Next, in FIG. 1, temperature: 375 ° C., pressure: 1
00Pa, diethylsilane: 80cc / min, oxygen: 120
FIG. 3 is an enlarged cross-sectional view (an electron micrograph is a drawing) showing an oxide film when the oxide film is formed under the condition of cc / min.

In FIG. 1, 1 is a wafer substrate, 2 is a hole formed in the wafer by a method such as etching, and 3 is an oxide film.

As shown in FIG. 1, the oxide film 3 is uniformly formed on the periphery of the hole 2, the hole wall and the bottom.

[0018]

As described above, according to the present invention, LP-
It is possible to form a uniform oxide film by a silane-oxygen based gas in the CVD method and improve productivity.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an oxide film formation result according to an embodiment of the present invention.

[Explanation of symbols]

 1 Wafer substrate 2 Hole 3 Oxide film

Claims (2)

[Claims] 1. A wafer processing method, characterized in that diethylsilane and oxygen are used as an oxidizing gas to form an oxide film on a wafer surface. 2. Diethylsilane and oxygen are used as an oxidizing gas, the ambient temperature is 350 ° C. to 450 ° C., and the pressure is 70 Pa to.
100 Pa, diethylsilane flow rate 40 cc / min-80 cc / m
A wafer processing method, characterized in that an oxide film is formed on a wafer surface under an oxide film forming condition of oxygen flow rate of 60 cc / min to 120 cc / min.