JP2001192836A - Plasma cvd system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for preventing the reduction in deposition rate caused by the continuous film deposition on a plurality of substrates in the plasma CVD method using TECS (tetra ethyl ortho silicate), etc., as source gas. SOLUTION: In a plasma CVD system 10, a shower plate 16 and a susceptor 18 are both constituted of an aluminum plate having aluminum oxide film on the surface. As a result, even if the deposition of SiO2 film is continuously applied to a plurality of substrates, temperature distribution in a vacuum chamber 12 becomes more uniform than heretofore. Resultantly, deposition rate does not fall but becomes nearly constant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a plasma CVD apparatus BACKGROUND OF THE INVENTION, in particular, in the manufacturing process of the liquid crystal display device, the TEOS / O ₂ based plasma CVD method on a glass substrate, S
The present invention relates to a plasma CVD apparatus for forming an iO ₂ film.

[0002]

2. Description of the Related Art As a method of forming an insulating film having good film quality at a low temperature on a large-sized glass substrate, there is a TEOS / O ₂ plasma CVD method. Reference numeral 110 in FIG.
1 shows a prior art / O ₂ plasma CVD apparatus, which has a vacuum chamber 112. An evacuation system 123 is provided outside the vacuum chamber 112, and the evacuation system 1
When the 23 is activated, the inside of the vacuum chamber 112 can be evacuated.

[0003] On the ceiling side of the vacuum tank 112,
The electrode 131 is provided in a state where the electrode 131 is electrically insulated. On the other hand, a voltage source 122 is disposed outside the vacuum chamber 112, and the electrode 1
31 is configured to be able to apply a high-frequency voltage.

A pedestal 117 is provided on the bottom wall inside the vacuum chamber 112.
Are arranged, and the mounting table 118 is attached to the surface thereof. The mounting table 118 has two plate members 153 and 154 and a linear sheath heater 155 as shown in a sectional view of FIG. Each plate member 153, 15
On the surface of No. 4, grooves 165 having a predetermined pattern are formed as shown in FIG.

The plate members 153 and 154 are arranged in close contact with each other such that the grooves 165 overlap each other in a state of being in close contact with each other. The sheath heater 155 is bent in the same shape as the grooves 165, and is arranged in a space formed between the grooves 165 formed on the respective surfaces in a state where the plate members 153 and 154 are in close contact with each other. ,
It is in close contact with both of the two plate members 153 and 154.

[0006] The sheath heater 155 is connected to a power source (not shown) arranged outside the vacuum chamber 112. Mounting table 1
Reference numeral 18 denotes a state in which the substrate 121 is placed on the plate-like member 153, and when a power source thereof is activated to energize the sheath heater 155, a resistance heating element (not shown) provided therein generates heat, and The entire 153 and 154 are uniformly heated, and the temperature of the substrate 121 can be uniformly increased.

[0007] The electrode 131 has an electrode body 113 and a shower plate 116. The electrode body 113
It is formed in a container shape, and one end of a gas introduction pipe 119 is connected to a bottom portion of the container. Gas introduction pipe 1
A gas cylinder (not shown) is connected to the other end of 19, so that gas can be introduced into the container-like space of the electrode body 113.

[0008] The shower plate 116 is
3 so as to close the container opening, and the electrode body 1
13 and the shower plate 116 form a space. A large number of holes 115 are formed in the shower plate 116, and when gas is introduced into the space from the gas introduction pipe 119, this space becomes a gas storage chamber 114, which is once filled with introduced gas, , And can be blown out from each hole 115 into the vacuum chamber 112.

[0009] The plasma CVD apparatus 11 having such a configuration.
When forming a SiO ₂ film on a plurality of glass substrate surfaces by TEOS / O ₂ plasma CVD using 0, first, the inside of the vacuum chamber 112 is evacuated by the evacuation system 123 and the sheath heater 155 is energized. And the mounting table 118
Is heated to raise the temperature. When the pressure in the vacuum chamber 112 reaches a predetermined pressure and the mounting table 118 is heated to a predetermined temperature, while maintaining a vacuum state, one
The second substrate 121 is loaded and placed on the mounting table 118.

When the temperature of the substrate 121 is raised to a predetermined temperature,
A reactive gas is introduced into the gas storage chamber 114 and sprayed from the shower plate 116 onto the surface of the substrate 121.
In this state, when the voltage source 122 is activated and a high-frequency AC voltage is applied to the electrode 131, a discharge is generated, and the discharge generates plasma to decompose the raw material gas, which is vapor-phase grown on the surface of the substrate 121. SiO _{2 on} the surface of the substrate 121
A film is formed. When the SiO ₂ film having a predetermined thickness is formed, the supply of the high-frequency power and the introduction of the reactive gas and the dilution gas are stopped, and the substrate 121 is carried out of the vacuum chamber 112 by a transport system (not shown).

Subsequently, an unprocessed substrate is newly added to the vacuum chamber 1.
After being loaded into the mounting table 12 and mounted on the mounting table 118, an SiO ₂ film having a predetermined thickness is formed on the surface of the loaded substrate through the same steps as those described above. By repeating the above operation, an SiO ₂ film can be formed on the surfaces of a plurality of substrates.

Such a TEOS / O ₂ plasma CV
In the method D, the reactive gas is activated in the plasma, so that the substrate 121 can form a thin film even at a relatively low temperature.

Then, the capacity of the vacuum chamber 112 is increased,
When a large-area substrate can be accommodated, a relatively uniform thin film can be formed on a relatively large substrate surface by the plasma CVD method.

However, in the above-described film forming method, when a thin film is formed on a plurality of substrates continuously in the same vacuum chamber, there has been a problem that the film forming speed is gradually reduced. The inventors of the present invention, in the predetermined processing time for each substrate, the plurality of substrate surface, when depositing the SiO ₂ film are continuously in the same vacuum chamber, and the number of processed substrates, each An experiment was conducted to examine the relationship with the thickness of the SiO ₂ film formed on the substrate. The experimental result is shown in the curve (Y) of FIG. In FIG. 7, the horizontal axis indicates the number of processed substrates, and the vertical axis indicates the thickness of the thin film formed on each substrate surface when the thickness of the first substrate is 1, (Referred to as an oxide film thickness).

As shown by the curve (Y), as the number of processed substrates increases, the film formation rate decreases, and the normalized film thickness of the twelfth substrate becomes about 0.85, It was confirmed that the film thickness was about 85% of the film thickness of the formed thin film, and that as the number of processed films increased, the film forming speed was reduced.

[0016]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned disadvantages of the prior art, and its object is to form an insulating film continuously on a plurality of substrates.
It is an object of the present invention to provide a technique in which a decrease in the deposition rate is reduced even when the number of processed films increases.

[0017]

Means for Solving the Problems The inventors of the present invention have investigated the cause of the decrease in the film forming speed in the conventional apparatus. In the conventional device, the shower plate 116 is made of a plate made of Hastelloy and an aluminum oxide thin film formed on the surface thereof. On the other hand, the plate members 153 and 154 forming the mounting table 118 are shown in FIG. As shown in the figure, the shower plate 116 and the plate-like member 15 are composed of carbon graphite plates 163 and 164 and aluminum oxide films 173 and 174 formed on their respective surfaces by thermal spraying.
3, 154 are different. In the TEOS / O ₂ plasma CVD method, the film formation rate is greatly affected by the temperature in the vacuum chamber. However, in the conventional apparatus, since the materials of the shower plate and the mounting table are different as described above,
The temperature change rate of the shower plate is different from the temperature change rate of the mounting table. Therefore, the inventors of the present invention have found that when the number of processed wafers increases and the temperature inside the vacuum chamber changes, the temperature distribution in the vacuum chamber becomes non-uniform, I guessed it was.

Based on this assumption, experiments were repeated while changing the material of the mounting table and the shower plate. As a result, both the mounting table and the shower plate were made of aluminum having an aluminum oxide film formed on the surface. As a result, it has been found that even if the number of substrates processed increases, the film forming rate for each substrate becomes substantially constant.

The present invention has been made based on such knowledge, and the invention according to claim 1 has a vacuum chamber, an electrode provided in the vacuum chamber, and an electrode provided in the vacuum chamber, A mounting table having a mounting surface on which the substrate can be mounted,
The electrode is formed between the electrode main body, the shower plate provided on the placement surface side of the electrode main body, and the electrode main body, and the shower plate, so that gas can be introduced into the inside. A gas storage chamber is provided, and the source gas introduced into the gas storage chamber is blown out from the plurality of holes provided in the shower plate toward the mounting table, and a voltage is applied to the electrode to discharge. A plasma CVD apparatus for forming a thin film on a substrate surface by decomposing the source gas with plasma generated between the substrate and the shower plate by the discharge and performing vapor phase growth. The table and the shower plate,
An aluminum oxide film is formed on at least a surface of the mounting table, the surface being opposed to the mounting surface of the shower plate. According to a second aspect of the present invention, there is provided the plasma CVD apparatus according to the first aspect, wherein the mounting table has a heating element therein and heats the substrate while the substrate is mounted. It is characterized by being constituted so that it can be performed. The invention according to claim 3 provides the plasma C according to claim 2.
In the VD apparatus, the mounting table includes a plate-shaped member on which the aluminum oxide film is formed and the substrate is disposed, and the heating element is disposed below a bottom surface of the plate-shaped member. With the above-described configuration, even when the number of substrates processed increases, the film forming rate on each substrate hardly decreases and becomes substantially constant.

[0020]

Embodiments of the present invention will be described with reference to the drawings. TEOS / O is used as a method for forming an insulating film with good film quality at a low temperature on a large-area glass substrate.
_{There is a two-} system plasma CVD method. The symbol 10 in FIG.
1 shows a plasma CVD apparatus according to the present embodiment for performing an OS / O ₂ plasma CVD method. This plasma CVD
The device 10 has a vacuum chamber 12. A vacuum evacuation system 23 is provided outside the vacuum chamber 12 so that the inside of the vacuum chamber 12 can be evacuated.

An electrode 31 is provided on the ceiling side of the vacuum chamber 12 while being electrically insulated from the vacuum chamber 12. On the other hand, a voltage source 22 is disposed outside the vacuum chamber 12 so that a high-frequency voltage can be applied to the electrode 31 while the vacuum chamber 12 is set at the ground potential.

A pedestal 17 is arranged on a bottom wall inside the vacuum chamber 12, and a mounting table 18 is attached to a surface of the pedestal 17.
The surface of the mounting table 18 is flattened, and is configured so that the substrate 21 can be mounted horizontally on that portion. In this state, the surface of the substrate 21 faces in parallel with the surface of the electrode 31.

The mounting table 18 has two plate members 53 and 54 and a linear sheath heater 55, as shown in FIG. On the surface of each plate member 53, 54, a groove 65 having a predetermined pattern is formed as shown in FIG.

The sheath heater 55 is bent in the same shape as the groove 65. When the plate members 53 and 54 are brought into close contact with each other while the sheath heater 55 is housed in the groove 65, the sheath heater 55 is , 54 both grooves 65
And is configured to be in close contact with both of the plate members 53 and 54.

As shown in FIG. 2C, the sheath heater 55 has a tube 58 made of a nickel-based alloy (trade name: Inconel) containing 16% chromium and 7% iron. A linear resistance heating element (NiCr) 56 is inserted into the tube 58 and filled with an insulator (MgO) 57, and the tube 58 and the resistance heating element 56 are insulated by the insulation 57. Have been.

The sheath heater 55 is connected to a power source (not shown) arranged outside the vacuum chamber 12,
When the power is turned on and the sheath heater 55 is energized while the substrate 21 is placed on the substrate 21, the resistance heating element 56 generates heat, and the entire plate members 53 and 54 are uniformly heated.
1 can be heated.

The electrode 31 has an electrode body 13 and a shower plate 16. The electrode body 13 is formed in a container shape, and a gas introduction pipe 19 is
Are connected at one end. A gas cylinder (not shown) is connected to the other end of the gas introduction pipe 19 so that gas can be introduced into the container-like space of the electrode body 13.

The shower plate 16 is fixed so as to close the opening of the container of the electrode body 13, and a space is formed by the electrode body 13 and the shower plate 16. A large number of holes 15 are formed in the shower plate 16, and when gas is introduced into the space from the gas introduction pipe 19, this space becomes the gas storage chamber 14, which is once filled with the introduced gas, , And can be blown out from each hole 15 into the vacuum chamber 12.

When an SiO ₂ film is formed on the surface of a plurality of glass substrates by the TEOS / O ₂ plasma CVD method using such a plasma CVD apparatus 10, first, the inside of the vacuum chamber 12 is evacuated by the vacuum exhaust system 23. While evacuating,
By energizing the sheath heater 55, the mounting table 18 is heated and heated. When the pressure in the vacuum chamber 12 reaches a predetermined pressure and the mounting table 18 is heated to a predetermined temperature, the first substrate 21 is loaded into the vacuum chamber 12 while maintaining a vacuum state. Place on top.

When the temperature of the substrate 21 is raised to a predetermined temperature, a reactive gas is introduced into the gas storage chamber 14 and sprayed from the shower plate 16 onto the surface of the substrate 21. In this state, when the voltage source 22 is activated and a high-frequency AC voltage is applied to the electrode 31, a discharge is generated, and the discharge generates plasma to decompose the raw material gas and vapor-phase grow on the surface of the substrate 21. An SiO ₂ film is formed on the surface of the substrate 21.

When the SiO ₂ film having a predetermined thickness is formed, the supply of the high-frequency power and the introduction of the source gas are stopped, and the substrate 21 is carried out of the vacuum chamber 12 by a transfer system (not shown). Subsequently, the unprocessed substrate is newly carried into the vacuum chamber 12 and the
After being placed on the substrate, an SiO ₂ film having a predetermined thickness is formed on the surface of the loaded substrate through the same steps as described above. By repeating the above operation, an SiO ₂ film can be formed on the surfaces of a plurality of substrates.

In the plasma CVD apparatus 10 of the present embodiment, the two plate members 53 and 54 described above are each made of an aluminum plate 6 as shown in the sectional view of FIG.
3 and 64, and aluminum oxide films 73 and 74 formed on the respective surfaces by anodic oxidation.

Here, the anodic oxidation method means that a positive voltage is applied to the aluminum plate and a negative voltage is applied to the cathode material while the aluminum plate and the cathode material are immersed in the aqueous electrolyte solution, so that the aqueous electrolyte solution is electrically This is a method of decomposing, generating oxygen in an aqueous solution by electrolysis, and forming a thin film of aluminum oxide on the surface of an aluminum plate by a chemical reaction between the oxygen and aluminum. Since a large number of holes are formed on the surface of the aluminum oxide thin film thus formed, the aluminum oxide thin film is exposed to high-temperature steam to fill the holes, thereby enhancing the corrosion resistance of the aluminum oxide thin film.

The cross section of the shower plate 16 is, as shown in FIG.
4, an aluminum plate 6 having a plurality of holes 15 formed therein.
1 and an aluminum oxide film 62 formed on the entire surface by anodic oxidation.

As described above, the plasma CVD of the present embodiment
In the apparatus 10, the shower plate 16 and the mounting table 18 arranged in the vacuum chamber 12 are both made of aluminum having an aluminum oxide film formed on the surface.

By using aluminum having a good thermal conductivity as the base material as described above, the temperature change before and after the substrate is removed and before and after the film formation is suppressed to a small extent.
The temperature distribution in the vacuum chamber becomes more uniform than in the related art in which the material of the mounting table 118 is different. For this reason, TEOS whose film formation rate is greatly affected by the temperature distribution in the vacuum chamber
Even when a film is continuously formed on a plurality of substrates by the / O ₂ plasma CVD method, the film forming speed for each substrate can be made substantially constant.

The inventors of the present invention use the plasma CVD apparatus 10 of the present embodiment, while keeping the processing time for each substrate constant, and continuously depositing Si on the surfaces of a plurality of substrates in the same vacuum chamber.
When an O ₂ film was formed, an experiment was conducted to examine the relationship between the number of processed substrates and the thickness of the SiO ₂ film formed on each substrate.
The experimental result is shown in a curve (X) of FIG. In FIG. 4, the horizontal axis indicates the number of processed substrates, and the vertical axis indicates the thickness of the thin film formed on each substrate surface when the thickness of the first substrate is 1, (Referred to as an oxide film thickness).

As shown by the curve (X), the normalized thickness of the twelfth substrate is about 0.98, which is about 98% of the thickness of the thin film formed on the first substrate. When the plasma CVD apparatus 10 of the present embodiment was used, it was confirmed that the film formation rate hardly decreased even when the number of substrates processed increased.

In this embodiment, the aluminum oxide film is formed by the anodic oxidation method. However, the present invention is not limited to this, and the aluminum oxide film may be formed by, for example, a thermal spraying method. In the present embodiment, the aluminum oxide films 73 and 74 are formed on the entire surface of the plate members 53 and 54 constituting the mounting table 18, and the aluminum oxide film 62 is formed on the entire surface of the shower plate 16. However, the present invention is not limited to this. The mounting table 18 only needs to have an aluminum oxide film formed on at least the surface on which the substrate is mounted, and the shower plate 16 faces at least the substrate. It is sufficient that an aluminum oxide film is formed on the surface.

Further, in the present embodiment, the mounting table 18 has the two plate members 53 and 54, but the present invention is not limited to this. Alternatively, a configuration may be adopted in which a sheath heater is embedded.

In this embodiment, the sheath heater 55 is provided inside the mounting table 18 so that the temperature of the substrate can be raised while the substrate is mounted. Is not limited to this, and may not be configured to heat the substrate.

[0042]

As described above, even when a film is continuously formed on a plurality of substrates, the film forming speed can be made substantially constant.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a plasma CVD apparatus according to an embodiment of the present invention.

2A is a cross-sectional view illustrating a configuration of a mounting table according to an embodiment of the present invention. FIG. 2B is a plan view illustrating a plate member according to an embodiment of the present invention. Sectional drawing explaining the sheath heater of one Embodiment.

FIG. 3 is a cross-sectional view illustrating a shower plate according to an embodiment of the present invention.

FIG. 4 is a graph illustrating the operation and effect of the plasma CVD apparatus according to one embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a conventional plasma CVD apparatus.

FIG. 6A is a cross-sectional view illustrating a configuration of a conventional mounting table. FIG. 6B is a plan view illustrating a conventional plate-like member.

FIG. 7 is a graph illustrating a problem of the conventional device.

[Explanation of symbols]

10 Plasma CVD apparatus 12 Vacuum chamber 1
3 ... electrode body 14 ... gas storage chamber 15 ... hole 16 ... shower plate 18 ... mounting table
31 ... electrodes 53, 54 ... plate-like members 61 ...
Aluminum plates 62, 63, 64 ... aluminum oxide film

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Naoto Tsuji 523 Yokota, Yamatake-cho, Yamatake-gun, Chiba Japan Nippon Makoto Technology Co., Ltd. (72) Inventor Yasuo Shimizu 2500 Hagizono, Chigasaki-shi, Kanagawa F-term (reference) 4K030 AA06 AA14 BA44 CA06 CA17 EA05 FA01 KA23 KA30 LA18 5F045 AA08 AB32 AC07 AC11 BB01 EF05 EF11 EH04 EH05 EH08 EK07 EK08

Claims (3)

[Claims] 1. A vacuum chamber; an electrode provided in the vacuum chamber; and a mounting table provided in the vacuum chamber, the mounting table having a mounting surface on which a substrate can be mounted. An electrode body, a shower plate provided on the placement surface side of the electrode body, and a gas storage formed between the electrode body and the shower plate, and configured to allow a gas to be introduced therein. A raw material gas introduced into the gas storage chamber is blown out from the plurality of holes provided in the shower plate toward the mounting table, and a voltage is applied to the electrode to cause discharge,
Plasma C for forming a thin film on the surface of the substrate by decomposing the source gas with plasma generated between the substrate and the shower plate by the discharge and performing vapor phase growth.
A VD apparatus, wherein the mounting table and the shower plate are made of aluminum, and at least a surface of the mounting table and a surface facing the mounting surface of the shower plate include aluminum oxide. Plasma CVD characterized by forming a film
apparatus. 2. The mounting table according to claim 1, further comprising a heating element therein.
2. The plasma CVD apparatus according to claim 1, wherein the substrate can be heated while the substrate is mounted. 3. The mounting table according to claim 2, further comprising a plate-shaped member on which the aluminum oxide film is formed and on which the substrate is disposed, wherein the heating element is disposed below a bottom surface of the plate-shaped member. Plasma CVD apparatus.