JP2001351867A - Method and apparatus of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to stabilize TFT characteristics. SOLUTION: After periodical cleaning, electric discharge is performed with a mixed gas of H2 and Ar without the substrate in a deposition system. After that, the film quality is made stable, and the TFT with satisfactory characteristics can be obtained from the first stage of cleaning.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a thin film to be used as a semiconductor layer and an insulating film layer of a thin film transistor (hereinafter referred to as a TFT) for forming an image display device in combination with a liquid crystal or the like, and an apparatus for manufacturing the semiconductor. .

[0002]

2. Description of the Related Art A conventional thin film manufacturing method will be described below.

FIG. 3 is a sectional view showing the structure of a main part of a TFT. A gate electrode 2 is formed on a glass substrate 1, an amorphous silicon semiconductor layer 4 is formed via a gate insulating film 3, and source and drain electrodes 6a and 6b are formed via n + amorphous silicon semiconductor layers 5a and 5b. It is formed.

Conventionally, the gate insulating film 3, the amorphous silicon semiconductor layer 4, the n + amorphous silicon semiconductor layers 5a, 5
b is manufactured by a plasma chemical vapor deposition apparatus using a glow discharge as shown in FIG. The plasma chemical vapor deposition apparatus shown in FIG.
2 is a capacitive coupling type which is installed in parallel, and the substrate is installed on the counter discharge electrode 12.

In this plasma-enhanced chemical vapor deposition apparatus, when depositing a thin film, the film adheres to the side wall of the deposition chamber 11, the discharge electrode 14, and the like, and the thickness increases. In order to prevent the adhered film from peeling off, cleaning for removing the adhered film is periodically performed by glow discharge using NF ₃ gas and CF ₄ gas as main components. Further, in order to stabilize the quality of a film to be formed, a film is deposited without a substrate immediately after the periodic cleaning, and then a thin film is deposited on a substrate for forming a TFT.

[0006]

However, in the above-mentioned conventional method, in order to improve the film quality, the deposited film thickness becomes large immediately after the periodic cleaning, and the deposited film is deposited at the time of deposition on a substrate for manufacturing a TFT. The film that has accumulated and adhered in the chamber 11 tends to peel off. In addition, inconvenient impurities in the thin film such as the gate insulating film and the amorphous silicon semiconductor layer tend to cause inconvenience in the characteristics of the TFT, and particularly in the TFT immediately after the periodic cleaning, the inconvenience is remarkable.

In addition, it takes time to remove the film even during the periodic cleaning, which is a problem from the viewpoint of improving productivity.

In order to solve the above-mentioned conventional problems, the present invention performs thin deposition without installing a substrate after periodic cleaning, and stabilizes the film quality of a gate insulating film and an amorphous silicon semiconductor layer formed thereafter. Accordingly, it is an object of the present invention to further reduce inconvenience of TFT characteristics and improve productivity.

[0009]

A method of manufacturing a semiconductor device according to the present invention includes a step of depositing a thin film on a substrate using a plasma enhanced chemical vapor deposition apparatus, and discharges at a high frequency in the deposition apparatus. Later, a thin film is deposited on the substrate for the semiconductor device.

Further, the method of manufacturing a semiconductor device according to the present invention comprises:
Discharge performed before manufacturing a semiconductor device is characterized by introducing hydrogen gas and a mixed gas thereof to a place where the substrate for a semiconductor device is installed.

Further, a method of manufacturing a semiconductor device according to the present invention
The mixed gas contains an inert gas.

Further, a method of manufacturing a semiconductor device according to the present invention
The inert gas is one of Ar and He.

Further, a method of manufacturing a semiconductor device according to the present invention
The semiconductor device is a thin film transistor.

Further, a method of manufacturing a semiconductor device according to the present invention
The thin film is a semiconductor thin film containing silicon as a main component.

Further, a semiconductor manufacturing apparatus according to the present invention has the manufacturing method according to any one of the first to sixth aspects.

As described above, according to the present invention, the residual component of the cleaning gas adsorbed on the material constituting the apparatus exposed after the cleaning in the deposition chamber is periodically replaced with hydrogen gas and Ar gas.
The removal by the discharge with an inert gas represented by the above can suppress the incorporation of unnecessary impurities into the thin film such as the gate insulating film and the amorphous silicon semiconductor layer to be manufactured. As a result, the film quality is stabilized and the TFT characteristics are improved. It is possible to improve the characteristics of the TFT and further reduce the problem.

Further, the liquid crystal display device of the present invention has a seventh aspect.
And a semiconductor manufactured by the semiconductor manufacturing apparatus described in (1).

Thus, the present invention can provide a higher quality liquid crystal display device.

[0019]

Embodiments of the present invention will be described below. The frequency is 13.56 MH as shown in FIG.
z using a chemical vapor deposition apparatus using a glow discharge of z
By introducing iH ₄ , NH ₄ , and H ₂ gas, a gate insulating film and an amorphous silicon semiconductor layer were formed, and the TFT of FIG. 3 was manufactured. FIG. 1 shows the mobility of the TFT with respect to the accumulated film thickness after cleaning with NF ₃ gas. As shown in the figure, but the mobility as accumulated film thickness of the deposition chamber immediately after the cleaning of the deposition chamber is increased to increase, without the substrate immediately after cleaning the H ₂ gas to 2000 sccm, Ar
The gas was flowed at 400 sccm and the pressure was 1.3 × 1.33.
At 322 × 10 ⁻³ Pa (or 1.3 Torr), 400
By performing the glow discharge of W, the mobility was improved as compared with the conventional case, and the initial value was improved by 0.12 × 10 ⁻⁴ m ² / Vsec (or 0.12 cm ² / Vsec). And 0.9 × 1
In order to obtain a mobility of 0 ⁻⁴ m ² / Vsec (or 0.9 cm ² / Vsec) or more, the accumulated film thickness in the apparatus is conventionally 1.4 μm.
Although it was necessary, it could be reduced to 0.4 μm.

Further, when the mobility of the TFT fabricated by placing the substrate in the apparatus after cleaning was compared with the flow rates of H ₂ gas and Ar gas varied, the results shown in FIG. 2 were obtained. The degree improved with the introduction of H ₂ gas, and increased with the addition of the flow rate of Ar gas.

As described above, after cleaning, H ₂ gas, A
The mobility can be improved by performing the discharge with the r gas.

Although NF ₃ is used as the cleaning gas in the present embodiment, a fluorine-based gas such as CF ₄ or SF ₆ may be used. A similar effect can be obtained with a mixed gas of H ₂ gas and another inert gas, for example, a mixed gas of H ₂ and He.

In the present invention, the example of the gate insulating film and the amorphous silicon semiconductor thin film used for the TFT has been mainly described. The present invention is also effective for a method of manufacturing a semiconductor device having a step of depositing a thin film other than amorphous silicon using a phase deposition method, and a semiconductor manufacturing apparatus.

In the above description, sccm, which is a unit expressed as a non-SI unit, particularly, a unit expressed as sccm, is an abbreviation of Standard CCE and is a gas flow rate per unit time and a volume amount. , The unit of volume is c
In c, the unit of time is minutes (min). 200 above
When 0 sccm is converted in SI units, the unit of volume is cubic meter (m ³ ), and can be converted by multiplying by 10 ⁻⁶ ,
00 sccm becomes 2000 × 10 ⁻⁶ , and the volume of gas flow per unit time is expressed in cubic meters. S
The expression of the I unit is [m ³ / min].

[0025]

As described above, the present invention is stable by performing discharge with a mixed gas of H ₂ and Ar without cleaning the substrate in the deposition apparatus after cleaning the chemical vapor deposition apparatus for producing a semiconductor thin film. A thin film obtained is obtained, and a TFT exhibiting sufficient characteristics can be manufactured, which is of great industrial value.

[Brief description of the drawings]

FIG. 1 is a diagram showing mobility of a TFT with respect to a cumulative film thickness in a deposition chamber of a manufacturing apparatus in an embodiment of the present invention.

FIG. 2 is a diagram showing the mobility of a TFT manufactured by installing a substrate in an apparatus after cleaning in the embodiment of the present invention with respect to the flow rates of H ₂ and Ar gas.

FIG. 3 is a cross-sectional view of a main configuration of a TFT.

FIG. 4 is a schematic diagram of a chemical vapor deposition apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass substrate 2 Gate electrode 3 Gate insulating film 4 Amorphous silicon semiconductor film 5a, 5b n + amorphous silicon semiconductor film 6a, 6b Source / drain electrode 7 Channel stopper insulating film 11 Deposition chamber 12 Counter discharge electrode 13 Substrate 14 Discharge electrode 15 Gas 16 Discharge power supply

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shinji Nimura 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Hiroyoshi Takezawa 1006 Kadoma Kadoma Kadoma City, Osaka Matsushita Electric Industrial F Term (reference) 4K030 AA06 AA17 BA30 CA06 CA12 DA03 LA18 5F004 AA15 BD04 DA01 DA17 DA18 DA22 DA23 DA24 FA08 5F045 AA08 AB04 AB33 AC01 AC02 AC12 AC16 AC17 BB16 CA15 DP03 EB06

Claims (8)

[Claims] 1. A method of manufacturing a semiconductor device, comprising the step of depositing a thin film on a substrate using a plasma enhanced chemical vapor deposition apparatus, comprising the steps of:
A method for manufacturing a semiconductor device, comprising depositing a thin film on the substrate for the semiconductor device. 2. The semiconductor device according to claim 1, wherein the discharge performed before manufacturing the semiconductor device introduces a hydrogen gas and a mixed gas thereof into a place where the substrate for the semiconductor device is installed. Manufacturing method. 3. The method according to claim 2, wherein the mixed gas contains an inert gas. 4. The method according to claim 3, wherein the inert gas is one of Ar and He. 5. The method according to claim 2, wherein the semiconductor device is a thin film transistor. 6. The method according to claim 1, wherein the thin film is a semiconductor thin film containing silicon as a main component. 7. A semiconductor manufacturing apparatus having the manufacturing method according to any one of claims 1 to 6. 8. A liquid crystal display device comprising a semiconductor manufactured by the semiconductor manufacturing apparatus according to claim 7.