JP2001230207A - Plasma enhanced cvd system and method of manufacturing thin film transistor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma enhanced CVD system which can shorten the time required for hydrogenating the polycrystalline silicon of a thin film transistor(TFT) and forming a transparent film on the TFT. SOLUTION: This plasma enhanced CVD system is provided with a first fixed capacitor (1) for high-frequency power matching, a second fixed capacitor (2) for high-frequency power matching wired in parallel with the capacitor (1), and a switching means (4) which selectively switches the capacitors (1) and (2) for using either one or both of the capacitors (1) and (2).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma CVD apparatus used for manufacturing a thin film transistor (TFT) and a method for manufacturing a TFT, and more particularly to a method for manufacturing a TFT for a driving circuit integrated type liquid crystal display device. The present invention relates to a plasma CVD apparatus and a method for manufacturing a TFT.

[0002]

2. Description of the Related Art A polycrystalline silicon film is used as a thin film semiconductor for a TFT in a liquid crystal display device integrated with a driving circuit. A dangling bond, which is a bond having no bond partner, is generated on the surface of the polycrystalline silicon, but the mobility of the charge carrier is reduced in a channel portion where the dangling bond is formed on the surface. For this reason, a step of hydrogenation (hydrogen passivation) processing for reducing dangling bonds is provided. In a series of TFT manufacturing steps, the steps before and after the hydrogenation treatment are extracted as follows.

[0003] Formation of polycrystalline silicon film-Formation of gate insulation film-Formation of gate wiring-Doping of impurities in source / drain regions-Formation of interlayer insulation film-Activation treatment-Formation of source / drain wiring- Hydrogenation—Deposition of Transparent Protective Film In the hydrogenation, the polycrystalline silicon film is irradiated with hydrogen plasma in a film formation chamber of a plasma CVD (Chemical Vapor Deposition) apparatus. In this case, a substrate on which a polycrystalline silicon film is formed (hereinafter, a substrate on which a process such as film formation is performed is simply referred to as a “substrate” or an “object to be processed”)
There are two types of processing systems: a single wafer system in which hydrogen plasma processing is performed for each substrate, and a batch system in which a plurality of substrates are simultaneously subjected to hydrogen plasma processing. Since this hydrogenation process requires several tens of minutes, a batch-type hydrogenation process is performed in most cases. When performing a batch-type hydrogenation process, a tray on which a plurality of substrates are placed is used. In the case of a liquid crystal display device, since the size of the substrate is large, the tray on which a plurality of substrates are placed is large, for example, 1 m long and 1.2 m wide.

The duration of the hydrogenation depends on the mobility required for the charge carriers of the TFT. FIG.
FIG. 4 is a diagram illustrating a relationship between mobility of charge carriers of a TFT and hydrogenation processing time. It can be seen that for both the n-type TFT and the p-type TFT, the longer the hydrogenation time, the higher the mobility. In FIG. 13, the mobility of the n-type TFT is 65 cm.
^{In the} case where it must be ² / (V · s) or more, by performing the hydrogenation treatment for 40 minutes or more, it is possible to secure a charge carrier mobility of 65 cm ² / (V · s) or more in the n-type TFT.

After this hydrogenation treatment, the object to be processed is transported to another film forming apparatus, and in the transparent protective film forming step,
For example, a SiN film is formed, and a TFT is sequentially formed.

[0006]

According to the above-described manufacturing method, since the hydrogenation treatment and the formation of the transparent protective film are performed by separate apparatuses, a long processing time is required and the production efficiency is hindered. . By using a plasma CVD apparatus, it is highly possible that these two steps can be performed in the same apparatus. However, in the conventional plasma CVD apparatus, the types of plasma formed in the two processes are different, and different types of plasma cannot be formed in the same plasma CVD apparatus.

In the hydrogenation treatment, the inner surface and the tray of the film forming chamber are irradiated with hydrogen plasma for 40 minutes or more. For this reason, the tray and the inner surface of the film formation chamber are damaged, discolored, or deformed by the long-time irradiation of the hydrogen plasma. The tray is
Normally, two steps of the hydrogenation treatment and the formation of the transparent protective film are used repeatedly as one set. If it is deformed and damaged, troubles may occur during transportation by the loader or unloader, and the operation may have to be interrupted.
By the hydrogen plasma irradiation, the temperature of the tray rises,
Thermal distortion due to uneven distribution of temperature occurs, which also causes deformation. In addition, updating a film forming chamber for a liquid crystal display device requires high cost and interruption of operation. Therefore, it is very important to extend the life of the film forming chamber. As described above, the tray is large and expensive, so that the short life of the tray will increase the manufacturing cost.

SUMMARY OF THE INVENTION An object of the present invention is to provide a plasma CVD apparatus and a method of manufacturing a TFT, which enable continuous hydrogenation and transparent protective film formation in the manufacture of a TFT for a liquid crystal display. Another object is to provide a plasma CVD apparatus and a TFT manufacturing method capable of preventing a tray holding a substrate from being deformed or damaged in a hydrogenation process.

[0009]

A plasma CVD apparatus according to a first aspect of the present invention is a capacitively coupled plasma CVD apparatus that generates a plasma by applying a high frequency voltage between opposed electrodes. The plasma CVD apparatus includes a first fixed capacitor for input matching of high frequency power, a second fixed capacitor for input matching of high frequency power wired in parallel with the first fixed capacitor, and a first fixed capacitor. Switching means for selectively switching to use either one of the capacitor and the second fixed capacitor or both wired in parallel.

[0010] Since the matching condition of the input of the high-frequency power greatly differs depending on the type of plasma to be generated, when two fixed capacitors are not provided, two types of plasma are generated only by fine adjustment of the variable capacitor and the variable resistor. Input matching of RF power cannot be performed. With the above configuration, two types of plasmas having significantly different matching conditions for inputting high-frequency power can be generated in the same deposition chamber at different occasions. That is, hydrogenation of polycrystalline silicon is performed using a fixed capacitor matched to the input matching condition of RF power for generating hydrogen plasma, and, for example, to form SiN in the same apparatus. Using a matching capacitor for plasma generation, a transparent protective film S
iN can be deposited. Therefore, not only can the process be shortened, but also expensive plasma CVD
The number of devices can be reduced by one. In the process of forming the transparent protective film, the transparent protective film is naturally coated not only on the object to be processed but also on the inner surface of the film forming chamber. Therefore, the life of the film formation chamber can be extended. Further, it is possible to realize space saving in a clean room including wiring and piping. Note that one of the two fixed capacitors may be used for matching, or both may be connected in parallel and used for matching. When used in parallel, the capacitance of each capacitor is added, so that it is more economical than having one large-capacity capacitor.

In the plasma CVD apparatus according to the first aspect, as in the apparatus according to the second aspect, the first fixed capacitor is a matching capacitor for generating hydrogen plasma, and the second fixed capacitor is mounted on the substrate. It is desirable to use a matching capacitor for generating plasma of components of a film to be formed.

With this configuration, another film having a different matching condition from the hydrogen plasma, for example, a plasma of a component for forming a SiN film can be easily generated in the same film forming chamber. As a result, the above-described effects can be obtained.

According to the third aspect of the present invention, when manufacturing a TFT for a liquid crystal display device, the second aspect of the present invention is applied to a plasma CVD apparatus.
It is desirable that the film to be formed in the above device is a transparent protective film.

The plasma component film naturally adheres to the inner surface of the plasma CVD apparatus and the tray for mounting the substrate.
It is sputtered during the hydrogenation treatment and re-attaches on the substrate.
Therefore, in a liquid crystal display device in which it is essential to avoid deterioration in transparency, it is desirable that all of the protective films and the like be transparent films.

According to a fourth aspect of the present invention, there is provided the plasma CVD apparatus according to the second or third aspect, further comprising a tray which is conveyed by a conveying means in a state where the substrate is placed when the substrate is processed by the plasma CVD apparatus. The tray is coated with the membrane described above.

With the above structure, the tray is not deformed by the hydrogen plasma irradiation in the hydrogenation of the object to be processed including the polycrystalline silicon film, so that the transfer trouble does not occur and the process cost is reduced. It becomes possible. The tray is desirably a plate-shaped tray having a portion where a substrate is arranged is cut out. The reason is that since the transparent protective film is not formed in a portion of the substrate that is shaded when the transparent protective film is formed, stress or the like occurs between the portion coated with the transparent protective film and the uncoated portion. This is because distortion may remain. It is desirable that a support for easily supporting the substrate is attached to the tray. As described above, the life of the film forming chamber of the plasma CVD apparatus can be extended.

According to a fifth aspect of the present invention, there is provided the plasma CVD apparatus according to any one of the first to fourth aspects, wherein the first heating chamber and the second heating chamber, which are arranged in series and communicate with the entrance and exit of the film forming chamber, and the substrate. Transport means for transporting from one chamber to another.

The tray coated with the transparent protective film is circulated and used at regular intervals during continuous operation of the plasma CVD apparatus as a tray provided for the plasma CVD apparatus. When the tray is circulated and used for the hydrogenation process, the tray on which the object is placed before being introduced into the film formation chamber is heated to about 310 ° C. which is the processing temperature of the hydrogenation process. When this heating is performed in one step from room temperature to 310 ° C., hydrogen gas is released from the tray and the pressure becomes high, so that evacuation must be performed, for example, for 10 minutes or more. However, when this heating is performed separately in two separate chambers and the first stage is heated from room temperature to, for example, about 150 ° C., and the second stage is heated from 150 ° C. to about 310 ° C., the second chamber of the second-stage heating is heated. The hydrogen pressure does not become high, and it is not necessary to perform evacuation over time, and the process time can be shortened. It is desirable that the first heating chamber and the second heating chamber are separated by an openable and closable door. Further, it is desirable that there be an openable and closable door between the second chamber and the film formation chamber. However, since the amount of hydrogen released in the second chamber is small, it may be omitted.

According to a sixth aspect of the present invention, there is provided a method of manufacturing a thin film transistor using a plasma CVD apparatus, comprising: forming a polycrystalline silicon film on a substrate on which the thin film transistor is formed; A step of hydrogenating a substrate including a film in a hydrogen plasma in a film formation chamber, and in the same film formation chamber where the hydrogenation was performed, with respect to the hydrogenated substrate,
Continuously forming a film under different conditions.

With the above configuration, the hydrogenation treatment and the formation of the transparent protective film can be performed in the same plasma CVD apparatus. As a result, it is possible to reduce the processing time and the installation cost of the apparatus. Needless to say, this contributes to space saving in the clean room. Also,
The life of the film forming chamber of the plasma CVD apparatus can be extended.

According to a seventh aspect of the invention, there is provided a TFT manufacturing method.
In the method of the above, in the step of hydrogenation treatment, the substrate is mounted in a film formation chamber in a state of being mounted on a tray coated with a film, and is irradiated with hydrogen plasma. In the above, the thickness of the film on the tray surface which has been reduced is increased and reinforced.

With this configuration, the tray is naturally coated with the transparent protective film when forming the transparent protective film on the object to be processed, without providing a separate step of coating the surface of the tray with the transparent film. This tray uses this plasma CVD
Since it can be used repeatedly as a device provided in the apparatus, it functions as a transparent protective film for the tray during hydrogenation treatment, and does not deform even when subjected to hydrogen plasma irradiation for a long time. For this reason, transport trouble can be suppressed, and the process cost can be reduced.

According to the eighth aspect of the present invention, there is provided a TFT manufacturing method.
Or the manufacturing method of 7, further comprising a two-stage heating step of heating the tray with the substrate in two stages before mounting the tray with the substrate in the film forming chamber. A preheating step of preliminarily raising the temperature to a temperature lower than the hydrogenation temperature, and a preheated tray with the substrate conveyed from the first heating chamber in the second heating chamber. And a finishing heating step of raising the temperature to

According to this manufacturing method, a large amount of hydrogen gas is not released from the second heating chamber, and it is not necessary to perform evacuation for, for example, 10 minutes or more before introducing the object into the film forming chamber. It is possible to reduce the process time.

According to a ninth aspect of the present invention, there is provided the TFT manufacturing method according to the sixth aspect.
In any one of the above-described manufacturing methods, it is preferable that the film is a transparent film.

With this configuration, it is possible to form a transparent film that does not hinder use in a liquid crystal display device. Highly reliable S as a protective film and insulating film as a transparent film
An iN film can be formed.

According to a tenth aspect of the invention, there is provided a TFT manufacturing method.
In any one of the production methods of 6 to 9, the
And the irradiation energy density of the hydrogen plasma is 0.2 W /
cm ^TwoKeep below.

According to this manufacturing method, the temperature rise of the tray and the inner surface of the film forming chamber is limited, and the heat distortion due to the uneven temperature is suppressed, so that the deformation is also suppressed. As a result, troubles due to the deformed shape in the transfer of the tray and the like can be avoided.

In the method of manufacturing a TFT according to an eleventh aspect of the present invention, in the manufacturing method of any one of the sixth to tenth aspects, the substrate is a substrate on which a thin film transistor used for a drive circuit integrated type liquid crystal display device is formed. Is a polycrystalline silicon film constituting a thin film transistor.

The above-mentioned deformation of the tray is caused by the fact that the hydrogenation of polycrystalline silicon in the TFT of the driving circuit integrated type liquid crystal display device takes a long time, and the tray for mounting a large substrate for the liquid crystal display device is large. To be there,
This is particularly problematic. Therefore, the above effects can be obtained very effectively by applying the manufacturing method of the present invention.

[0031]

Embodiments of the present invention will now be described with reference to the drawings.

(Embodiment 1) First, for example, a SiN film, an oxide film or a two-layer film of an oxide film and a SiN film is formed as a base film 12 on a glass substrate 11 by a plasma CVD method. Thereafter, an amorphous silicon film 13 is formed by a low pressure CVD method or a plasma CVD method, and the amorphous silicon film 13 is made into a polycrystal (FIG. 1). Examples of the crystallization method include laser annealing and solid phase growth. After a polycrystalline silicon film 14 patterned in a channel shape is provided as shown in FIG. 2, a silicon oxide film 15 serving as a gate insulating film is formed on the polycrystalline material by plasma CVD as shown in FIG. . afterwards,
A Cr layer serving as a gate electrode is formed by sputtering and patterned into a gate electrode shape 16 (FIG. 4).
Thereafter, source / drain regions 17 and 19 are formed on both sides of the channel region 19 by ion implantation, and an interlayer insulating film 21 is formed by a plasma CVD method (FIG. 5). Next, a contact hole is formed, a source / drain wiring is formed, and as shown in FIG. Thereafter, the substrate is heated to about 400 to 500 ° C. for the purpose of activating the source / drain regions. Hydrogenation processing (hydrogen passivation) is performed after this activation processing. After hydrogenation, 400-500 ° C
When heated to a moderate degree, hydrogen may be lost from the hydrogenated portion. Therefore, at the stage where there is only a deposit that does not hinder the hydrogenation treatment of the polycrystalline silicon, and after the stage of FIG. Hydrotreating is performed.

The hydrogenation is performed by plasma CVD shown in FIG.
Irradiation with hydrogen plasma is performed using an apparatus.
In FIG. 7, the plasma CVD apparatus includes a matching unit 10 for inputting high-frequency power generated by a high-frequency power supply 7 to a main body (film forming chamber) 3 of the plasma CVD apparatus in a well-balanced manner. This matching unit 10
Has two variable capacitors 5 and 6 and an inductance 8
And two fixed capacitors 1 and 2 and a changeover switch 4 for switching between the two fixed capacitors. The variable capacitor 6 and each of the fixed capacitors 1 and 2
It is grounded so as to be in parallel with the film forming chamber 3. 2
Among the two fixed capacitors, the capacity of the matching fixed capacitor 1 for coating the SiN film which is a transparent film is 12
The capacitance of the fixed capacitor 2 for matching the generation of hydrogen plasma is about 800 pF.
The difference in capacitance with respect to the matching condition that cannot be adjusted by the variable capacitor 6 is compensated by using the fixed capacitor 1 or the fixed capacitor 2 by switching with the changeover switch 4 to obtain a matching condition. When generating hydrogen plasma in the hydrogenation process, the fixed capacitor 2 is used, and the fine adjustment is performed by using the variable capacitors 5 and 6 to match the input of the high-frequency power. At the time of the hydrogenation treatment, for example, as shown in FIG. 8, the hydrogen plasma 30 is applied to the object 32 mounted on the front side with two trays 31 arranged back to back. Each of the two trays 31 has a hollow portion 33 in which a portion where the object 32 is disposed is opened, and further includes a support 34 for easily supporting the object.

After the hydrogenation treatment, as shown in FIG.
An SiN film is formed as a transparent protective film on the FT object. The SiN film is formed on the object to be processed of the TFT, and also on the tray surface and the inner surface of the film forming chamber. Therefore, it is not necessary to use another plasma CVD apparatus for forming the SiN film on the tray surface. The conditions for forming the SiN film vary depending on the hydrogenation processing conditions. However, since the etching rate of the SiN film at the time of hydrogen plasma irradiation is about 1 nm / min, at least the SiN film is coated before the SiN film runs out. At the time of coating the SiN film, a plasma of the coating component is generated using the fixed capacitor 1.

As described above, by providing two fixed capacitors for matching in one plasma CVD apparatus, the processing time and the number of expensive plasma CVD apparatuses can be reduced. Furthermore, after preventing damage to the tray and film formation chamber and accompanying transport troubles,
Hydrogenation treatment of polycrystalline silicon can be sufficiently performed. Further, space saving of the clean room can be realized. For this reason, it is possible to obtain a TFT that stably secures high performance at low cost.

(Embodiment 2) When forming the passivation film of the embodiment 1, not only the object to be processed of the TFT but also the inner surface of the film forming chamber and the surface of the tray are transparent films.
An iN film can be formed. In the second embodiment, when performing the hydrogenation process using the tray on which the SiN film is formed and the film formation chamber, the tray on which the object to be processed is placed is heated in two stages. The two-stage heating is performed in a first heating chamber and a second heating chamber separated by an openable and closable door. For example, in the first stage in the first heating chamber, heating is performed from room temperature to about 150 ° C. with the door to the second heating chamber closed, and then transferred to the second heating chamber, and the temperature is raised from that temperature to 300 ° C. Heat to about ° C.

When the temperature was rapidly increased to about 300 ° C. in only one chamber used for comparison, hydrogen contained in the SiN film coated on the tray or the like escaped at a stretch, and as shown in FIG. The pressure rises to about 500 Pa, and it takes 10 minutes or more to exhaust the pressure. Due to this evacuation, the process time of the hydrotreating is extended, and the production efficiency is reduced.

On the other hand, when the heating is performed in two stages in the two chambers as in the present invention, the heating in both the first heating chamber and the second heating chamber can take several tens of Pa with heating without taking time for evacuation. Only the pressure rises to the extent. In FIG. 10, when the heating chamber is divided into two, the pressure in the second heating chamber is displayed. With the above-described heating method, it is not necessary to take time for evacuation, and the hydrogenation process can be shortened to increase the production efficiency. Although a heating chamber may be specially provided as the first heating chamber, the first heating may be performed in a loader of a plasma CVD apparatus without providing the heating chamber, which is rather preferable. In this case, a second heating chamber is provided continuously to the loader, and the object to be processed is sent from the second heating chamber to the film formation chamber.

(Embodiment 3) With the transparent film coated on the surface of the tray and the inner surface of the film forming chamber, the object to be processed in the stage shown in FIG. 6 is irradiated while changing the energy density of the hydrogen plasma in the hydrogenation process. did. The substrate temperature during the irradiation and the mobility of the charge carriers in the channel after the irradiation were measured. FIG. 11 shows the effect of RF power for exciting hydrogen plasma on mobility, and FIG. 12 shows the effect of hydrogenation time on substrate temperature. In FIG. 11 and FIG. 12, the RF power was changed to the tray area 6800c.
The value divided by m ² is used as the energy density of the hydrogen plasma. Therefore, the RF power of 0.2 W / cm ² is 13
60W. When suppressing the temperature rise as much as possible, in the present invention, the energy density of the hydrogen plasma is 0.2 W / c.
m ² or less, which corresponds to an RF power of 1360 W or less. By keeping this energy density, the temperature rise of the substrate can be suppressed to about 20 ° C. or less, and a sufficiently high mobility can be obtained. As a result, the deformation of the tray is also limited to a small range, and no transport trouble occurs.

Although the embodiments of the present invention have been described above, the embodiments of the present invention disclosed above are merely examples, and the scope of the present invention is not limited to these embodiments. Not limited. The scope of the present invention is shown by the description of the claims, and further includes all modifications within the meaning and scope equivalent to the description of the claims.

[0041]

According to the present invention, a TFT for a liquid crystal display device is provided.
In the manufacture of the semiconductor device, it is possible to reduce the number of plasma CVD devices for performing the hydrogenation process and the film formation process of the transparent protective film, and to shorten the process time. Plasma CVD
The life of the film forming chamber of the apparatus can be extended. In addition, the tray on which an object to be processed is placed used in these processes is suppressed from being deformed even if hydrogenation of polycrystalline silicon is performed for a long time. Furthermore, space saving of a clean room becomes possible. For this reason, it is possible to reduce the TFT manufacturing apparatus and maintenance costs, shorten the steps, and prevent transport troubles caused by tray deformation and the like. Further, when heating in the hydrogenation treatment, time loss can be reduced and production efficiency can be increased.

[Brief description of the drawings]

FIG. 1 is a TF for a liquid crystal display device manufactured in Embodiment 1.
FIG. 4 is a cross-sectional view at a stage when a base film and amorphous silicon are formed on the substrate at T.

FIG. 2 is a cross-sectional view at a stage where amorphous silicon is polycrystallized and patterned into a channel shape in the state of FIG. 1;

FIG. 3 is a cross-sectional view at a stage where a gate insulating film is formed on the state of FIG. 2;

FIG. 4 is a cross-sectional view showing a state in which a metal film for a gate wiring is formed in the state of FIG. 3 and patterned into a gate wiring, and then ion implantation is performed to form a source / drain region.

FIG. 5 is a cross-sectional view at a stage where an interlayer insulating film is formed on the state of FIG. 4;

6 is a cross-sectional view at the stage where a contact hole is provided in the interlayer insulating film in the state of FIG. 5, a metal film for source / drain wiring is formed, and patterned into a wiring shape.

FIG. 7 shows a plasma CV used in the first embodiment.
It is a schematic structure figure of D apparatus.

FIG. 8 is a perspective view showing an arrangement of substrates on a tray in the hydrogenation treatment in the first embodiment.

FIG. 9 is a cross-sectional view at a stage where a transparent protective film is formed after performing a hydrogenation treatment.

FIG. 10 is a diagram showing a change in pressure at the time of heating in a stage before the hydrogenation treatment according to the second embodiment. When two heating chambers are used, the pressure in the second heating chamber is displayed.

FIG. 11 is a diagram showing an influence of RF power of a hydrogenation process on the mobility of each charge carrier in a TFT channel portion in a third embodiment. Hydrotreating time: 60 minutes

FIG. 12 is a diagram showing an influence of a hydrogenation processing time on a substrate temperature at the time of the hydrogenation processing in the third embodiment.

FIG. 13 is a diagram showing the effect of hydrogenation processing time on the mobility of each charge carrier in a general TFT channel.
RF power: 1500W

[Description of Signs] 1 Input matching fixed capacitor for generating hydrogen plasma, 2 Input matching fixed capacitor for generating plasma of transparent film component, 3 Deposition chamber, 4 Changeover switch, 5, 6 Variable capacitor, 7 High frequency power supply, 8 Inductance , 10 high frequency power matching section, 11 TFT substrate for liquid crystal display device, 12 base film, 13 amorphous silicon film, 14 channel polycrystalline silicon, 15 gate insulating film, 16 gate wiring, 17, 18
Source / drain region, 19 channel region, 21 interlayer insulating film, 22/23 source / drain wiring, 24 transparent protective film (SiN film), 30 plasma, 31 tray, 32 workpiece (substrate), 33 hollow part of tray , 34 supports.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hideto Ishiguro 3-3-5 Yamato, Suwa City, Nagano Prefecture Seiko Epson Corporation F-term (reference) 4K030 AA17 BA29 BA30 BA40 BB03 BB13 FA03 GA02 GA12 KA08 KA45 LA15 5F045 AA06 AA08 AB03 AB04 AB32 AB33 AF07 BB08 CA15 EH12 EH19 EK27 EM09 EN05 HA11 HA16 HA18 HA23

Claims (11)

[Claims] In a capacitively coupled plasma CVD apparatus for generating a plasma by applying a high frequency voltage between opposed electrodes, a first fixed capacitor for input matching of high frequency power, and wiring in parallel with the first fixed capacitor. Switching means for selecting and switching to use one of the first fixed capacitor and the second fixed capacitor or both wired in parallel, the second fixed capacitor for input matching of high-frequency power, A plasma CVD apparatus comprising: 2. The method according to claim 1, wherein the first fixed capacitor is a matching capacitor for generating hydrogen plasma, and the second fixed capacitor is a matching capacitor for generating plasma of a component of a film to be formed on the substrate. The plasma CVD apparatus according to claim 1. 3. The film to be formed is a transparent protective film.
The plasma CVD apparatus according to claim 2. 4. The plasma CVD apparatus includes a tray that is transported by a transport unit while the substrate is loaded when processing the substrate with the plasma CVD apparatus, wherein the tray is coated with the film. Item 4. The plasma CVD apparatus according to item 2 or 3. 5. The plasma CVD apparatus includes a first heating chamber and a second heating chamber arranged in series communicating with an entrance and exit of a film forming chamber, and transport means for transporting a substrate from these chambers to the chamber. The plasma CVD apparatus according to claim 1. 6. A method for manufacturing a thin film transistor using a plasma CVD apparatus, comprising: forming a polycrystalline silicon film on a substrate on which the thin film transistor is formed; A step of performing a hydrogenation treatment in a hydrogen plasma in a chamber; and, in the same deposition chamber where the hydrogenation treatment was performed, continuously changing the conditions with respect to the hydrogenated substrate to form a film. Forming a thin film. 7. In the step of hydrogenation, the substrate is mounted on the film forming chamber in a state where the substrate is mounted on a tray coated with the film, and hydrogen plasma irradiation is performed. 7. The method of manufacturing a thin film transistor according to claim 6, wherein the thickness of the film on the tray surface reduced in the hydrogenation treatment is increased. 8. The method for manufacturing a thin film transistor includes a two-stage heating step of heating the tray with a substrate in two stages before mounting the tray with a substrate in a film forming chamber. A preheating step of preliminarily raising the temperature of the tray with a substrate to a temperature lower than a hydrogenation temperature, and the tray with a substrate in a preheated state transferred from the first heating chamber, A finishing heating step of raising the temperature to the hydrotreating temperature in the second heating chamber.
Or a method for manufacturing a thin film transistor according to item 7. 9. The method according to claim 6, wherein the film is a transparent film. 10. The method of manufacturing a thin film transistor according to claim 6, wherein in the hydrogenation treatment, the irradiation energy density of hydrogen plasma is maintained at 0.2 W / cm ² or less. 11. The substrate according to claim 6, wherein the substrate is a substrate on which a thin film transistor used for a driving circuit integrated type liquid crystal display device is formed, and the polycrystalline silicon is a polycrystalline silicon film forming the thin film transistor. 11. The method for manufacturing a thin film transistor according to any one of items 10 to 10.