JPH07235506A - Thinfilm forming method - Google Patents

Abstract

PURPOSE:To eliminate the high vacuum exhaust means by a method wherein a discharging gas having no thin film forming capacity at all is led in to produce plasma as a pretreatment step and then a reaction gas is substituted for the discharging gas without changing the plasma producing requirements to form a thin film on a substrate to be treated. CONSTITUTION:A substrate 6 is carried in a film forming chamber l and then a discharging gas (nitrogen gas) only not containing monosilane for stabilizing discharge is led into the chamber 1 for governing pressure. Next, an upper electrode 2 is impressed with high-frequency power from a high-frequency power supply for starting the discharge in the space between a lower electrode 3 holding the substrate 6 to be left intact until the plasma discharge is stabilized. Later, a reaction gas (monosilane, nitrogen gas) required for the formation of a silicon nitride film is led in to deposit the thin silicon nitride film on the substrate 6. Through these procedures, the high vacuum exhaustion before and after the film formation can be eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a thin film on a substrate to be processed such as a glass substrate by a plasma CVD method.

[0002]

2. Description of the Related Art Conventionally, as a method of forming a plurality of thin films on a substrate, there is known a method of forming a film by using a CVD apparatus having a plurality of film forming chambers in which parallel plate electrodes are installed. Hereinafter, a silicon nitride film (film type A) and an amorphous silicon film (film type B) are formed on a substrate by a conventional CVD apparatus having a plurality of film forming chambers in which parallel plate electrodes are installed based on the flowchart of FIG. I will explain how to do.

First, a substrate such as a glass substrate is carried into a film forming chamber I for forming a film type A and placed on the lower electrode of a parallel plate electrode (1). Evacuation before film formation is performed up to a high vacuum state (for example, 1 × 10 ⁻¹ Pa or less) (2), and the reaction gas A (monosilane, ammonia or nitrogen) necessary for film formation of the film type A is supplied to the film formation chamber I. It is introduced to adjust the pressure so that plasma discharge is possible (3), and power is supplied from the high frequency power source to the counter electrode to start plasma discharge to deposit the thin film A on the substrate (4). After continuing the discharge for a predetermined time, the supply of the electric power from the high frequency power supply is cut off to stop the plasma discharge, and at the same time, the supply of the reaction gas A is stopped (5). The inside of the film forming chamber I is evacuated to the high vacuum state (for example, 1 × 10 ⁻¹ Pa or less) (6), and the substrate on which the thin film A is formed is carried out from the evacuated film forming chamber I without breaking the vacuum. (7), this is membrane type B
It is carried into the film forming chamber II for formation (8). In the film forming chamber II, as in the film forming chamber I, the pre-film forming exhaust (9),
Introduction of reaction gas B (monosilane, hydrogen), pressure regulation (1
0), plasma discharge continued for a predetermined time (11), plasma discharge stopped (reaction gas B stopped) (12), film formation exhaust (1
After performing 3) in sequence, the substrate is unloaded (14).

In the pre-deposition exhaust of (2) and (9), the impurity gas is exhausted to clean the surface of the substrate and the discharge space as much as possible, and the impurities on the interface between the substrate and the formed thin film and on the thin film itself are removed. This is done for the purpose of preventing contamination. In the case of manufacturing a thin film transistor, in order to achieve this object, when the pressure during pressure adjustment is 100 Pa, the pressure is 1/1000 of that pressure, that is, 1 × 10 ⁻¹ Pa.
The following are required: Therefore, a wide area turbo molecular pump having a sufficient exhaust capacity is used for the exhaust before the film formation, and the pressure is reduced to this pressure in about 60 seconds. In (3) and (10) the introduction and regulation of the reaction gases A and B, only the reaction gas is introduced into the film forming chamber which has become a clean atmosphere due to the exhaust before the film formation, and about 30 before the start of discharge.
It takes a few seconds to maintain the constant pressure required for continuous discharge. A flow rate control mechanism is used for this gas introduction, and an automatically controlled throttle valve is used for pressure regulation. After the film formation chamber has a constant pressure due to the reaction gas, (4) or (1
The plasma discharge of 1) is started. To adjust the film thickness,
This is performed by controlling the duration of plasma discharge until the discharge is stopped in (5) and (12).

More specifically, it takes 120 seconds and 360 to form the film type A (silicon nitride) with a thickness of 400 nm and the film type B (amorphous silicon) with a thickness of 300 nm, respectively.
Second plasma discharge is required, the supply of the reaction gas is stopped at the same time as the discharge is stopped, and immediately after the film formation in (6) and (13), the gas is discharged. The purpose of this exhaust is the same as the exhaust before the film formation described above, and like the exhaust before the film formation, the wide-area turbo molecular pump having a sufficient exhaust capability takes 90 seconds to exhaust the gas.

When thin film transistors having the film type A (silicon nitride) and the film type B (amorphous silicon) as described above are continuously formed on a substrate in a vacuum by the parallel plate plasma CVD method. Requires two film forming chambers, and film formation requires a total time of 840 seconds.

[0007]

As described above, the conventional C
When a film is formed using a VD device, a high vacuum is performed in order to create a clean atmosphere in the film forming chamber before film formation. Therefore, a wide area turbo molecular pump having a sufficient exhaust capacity is used. In addition to the above, there is a problem that an evacuation time equal to or longer than the time required for film formation before and after film formation is required before the film formation chamber is made to have a required degree of vacuum.

Further, in the conventional CVD apparatus, it is necessary to provide the same number of film forming chambers as the number of kinds of film in order to form a film laminated in a plurality of layers, which increases the cost of the apparatus and the size of the apparatus. There is a problem that it becomes large and requires a large installation area.

Further, since the film thickness is controlled by controlling the discharge time, it is difficult to reliably detect the actual discharge start time, and it is difficult to control the film thickness with good reproducibility. There is also.

Further, as shown in FIG. 7, when electric power is applied from the high frequency power source, the reflected wave from the electrode plate after the start of discharge is large, and hence the reflected wave becomes smaller and becomes stable. There is a problem that the state of the initial plasma during the period is different from the state of the subsequent plasma, and the film quality at the initial stage of deposition becomes different from the film quality thereafter. This problem becomes more remarkable as the film deposition rate is increased, that is, the applied power and the supply amount of the reaction gas are increased.
Therefore, if an attempt is made to obtain a good film quality at the initial stage of deposition, a high deposition rate cannot be achieved, and the time required for film formation will increase and productivity will decrease.

Therefore, a main object of the present invention is to provide a thin film forming method which does not require a wide-area turbo molecular pump capable of reaching a high vacuum as an evacuation means.

Another object of the present invention is to form a thin film in which a plurality of layers of films can be continuously formed in a single film forming chamber and therefore the apparatus can be downsized. To provide a method.

Still another object of the present invention is to provide a thin film forming method capable of producing a film in which a plurality of layers having uniform film thickness and film quality are laminated.

Further, another object of the present invention is to provide a thin film forming method having a short film formation time and good productivity.

Still another object of the present invention is to provide a method of manufacturing a semiconductor device having excellent characteristics, which is composed of a plurality of laminated films including a semiconductor film.

[0016]

The thin film forming method of the present invention comprises:
Plasma is obtained by arranging a substrate to be processed in a vacuum container having a gas introduction port, and introducing high-frequency power to the reaction gas while introducing one or more kinds of reaction gas into the vacuum container from the gas introduction port. In the method of forming a thin film composed of a reaction product of a reaction gas on the substrate to be processed, prior to the introduction of the reaction gas, the reaction alone which does not substantially have the ability to form a thin film in a plasma state. While introducing a component gas that constitutes the gas, that is, a discharge gas composed of one or more gases contained in the above-mentioned two or more reaction gases and having substantially no thin film forming ability by itself. High-frequency power is applied to the discharge gas to generate plasma for pretreatment, and then the reaction gas is introduced in place of the discharge gas without substantially changing plasma generation conditions. It is characterized by forming a thin film on the target substrate Te.

As a vacuum container having a gas inlet used in the present invention, a known parallel plate type plasma CVD apparatus is exemplified.

The parallel plate type plasma generator is generally composed of
A vacuum container (deposition chamber) having a plurality of gas inlets and a pair of flat plate electrodes arranged in parallel vertically, a reaction gas supply system for supplying a reaction gas to the vacuum container, and a parallel plate electrode. It consists of a high-frequency power source that applies a high-frequency voltage of 13.56 MHz.

For film formation, a substrate to be processed is placed on the lower electrode, and a discharge gas and then a reaction gas are introduced from the gas inlet into the preceding process, and high frequency power is applied to the parallel plate electrodes to generate plasma. It is carried out by

In the pretreatment step, as the discharge gas, when the reaction in the next step is (a) formation of an amorphous silicon film, hydrogen gas which constitutes silane gas is used (b) formation of a silicon nitride film. In the case of (1) hydrogen gas that constitutes silane gas, (2) nitrogen gas, or (3) hydrogen that is an element that constitutes silane gas and ammonia gas that is a compound of nitrogen that is an element that constitutes nitrogen gas, In the case of (c) forming a silicon oxide film, oxygen gas is used.

In particular, in manufacturing a semiconductor device having a plurality of layers including a semiconductor film, when hydrogen gas is used as a discharge gas when the reaction in the next step is formation of an amorphous silicon film, Si-- H
Is effective to improve the characteristics of the semiconductor device.

In the present invention, the gas pressure in the vacuum container is set within the range of 100 to 300 Pa depending on the film to be formed. In the present invention, it is not necessary to make the inside of the vacuum container a vacuum lower than 10 Pa throughout the whole operation process, and therefore it is not necessary to use a vacuum pump having a large evacuation capacity such as a wide range turbo molecular pump.

In the present invention, for example, parallel plate electrode type C
The film formation using the VD device is performed as follows.

First, a substrate to be processed, for example, a glass substrate is placed on the lower electrode of the parallel plate electrode, and a high frequency power of 13.56 MHz is applied from the high frequency power source between the parallel plate electrodes while introducing a discharge gas. At this time, the flow rates of all the processing gases, the gas pressure, the inter-electrode distance, and the supplied power are set to values preset according to the type of film to be formed.

The surface of the substrate to be processed is cleaned by this plasma discharge. After the discharge is continued for a predetermined time to stabilize the discharge state, the supply of the discharge gas is stopped and the reaction gas is supplied. At this time, the inter-electrode distance is adjusted according to the type of film to be formed prior to the supply of the reaction gas. It is not necessary to change the gas pressure or the supplied power, but it is possible to adjust it. In this case, the supply pressure of the discharge gas is within the range of 10 to 100% of the reaction gas supply pressure, and the power set value under the supply of the discharge gas is 50% of the power set value under the reaction gas supply.
Within 100%.

The time of plasma discharge under the discharge gas is 0 when the plasma discharge time under the reaction gas is 1.
It is desirable to be in the range of 1 to 0.4, and when introducing the reaction gas in place of the discharge gas while maintaining the plasma discharge, it is desirable to introduce the reaction gas while keeping the gas pressure and the discharge power constant. .

In the case of forming a laminated film of a plurality of layers, after the first film formation is performed for a predetermined time, the supply of the reaction gas is stopped and the plasma discharge is maintained and the second film is formed. The discharge gas is introduced and the same process is repeated.

The present invention is effective when laminated by forming a plurality of layers such as silicon nitride-amorphous silicon-silicon nitride or silicon oxide-silicon nitride-amorphous silicon-silicon nitride. It is advantageously used in a manufacturing process of a channel etching type or channel insulating film type amorphous silicon TFT (inverse stagger type or stagger type) having the thin film of

[0029]

In the thin film forming method of the present invention, when discharge is generated by the discharge gas consisting of gas components not involved in thin film formation among the components of the reaction gas before forming the thin film, the film forming chamber is started at the start of discharge. Further, the substrate is exposed to an activated atmosphere, the impurity gas in the film forming chamber is easily replaced with the discharge gas, and it is not necessary to perform high vacuum exhaust by a wide area turbo molecular pump before and after film forming. It is possible to form a thin film in a clean atmosphere, and it is possible to form a good thin film in which impurities are not mixed in the initial stage of thin film formation in a short time. After a lapse of a predetermined time after the start of discharge, without changing the discharge power, a reaction gas consisting of a gas component of a discharge gas not involved in thin film formation and a gas component involved in thin film formation is introduced at substantially the same gas pressure. If the plasma discharge is continued at substantially the same discharge power, a stable plasma state can be maintained, so that the film quality at the initial stage of deposition and that after deposition can be the same, and the control of the film thickness is also easy. Become.

In particular, when hydrogen gas is used as a discharge gas when forming a laminated film composed of a plurality of layers including a semiconductor film, the state of the semiconductor interface is improved and a semiconductor device having excellent characteristics can be manufactured. .

[0031]

【Example】

Example 1 With reference to FIGS. 1 and 2, parallel plate plasma CVD
An example applied to the manufacture of a semiconductor film made of silicon nitride (film type A) and amorphous silicon (film type B) by the method will be described.

FIG. 1 is a diagram conceptually showing the CVD apparatus used in the present invention, and FIG. 2 is a parallel plate plasma CV of the present invention.
6 is a flowchart for explaining a method of manufacturing a semiconductor film by the D method.

In FIG. 1, plasma generating electrodes 2 and 3 are vertically opposed to each other in a vacuum-tightly-formed film forming chamber I so as to oppose each other. The upper electrode 2 is electrically insulated from and supported by the film forming chamber I, is exposed in the film forming chamber 1, and the lower electrode 3 is provided with a heater 4 below it. The lower electrode 3 is grounded together with the film forming chamber 1, and the high frequency power source 5 is connected between the grounded lower electrode 3 and the upper electrode 2. The substrate 6 to be grown by chemical vapor deposition is placed on the lower electrode 3, and plasma is generated by applying high frequency power to both electrodes in the reaction gas introduced from the gas inlet 7 into the film forming chamber 1. Then, the film forming component in the gas is chemically vapor-deposited on the substrate 6. Reference numeral 8 is an exhaust port that communicates with an exhaust pump (not shown).

In the following description, the reference numerals shown in parentheses are the reference numerals for the steps shown in the flow chart of FIG.

In this embodiment, first, silicon nitride and
The substrate is carried into a film forming chamber I for laminating and depositing an amorphous silicon film (1), the substrate and the film forming chamber are cleaned before the film type A is formed, and monosilane is added to stabilize the discharge. Only the discharge gas A (nitrogen gas) containing no gas was introduced, and the pressure was adjusted (100 to 300 Pa) so that a predetermined plasma discharge was possible (2).

At this time, it took 30 seconds to maintain the above pressure state. A flow rate control mechanism was used for gas introduction, and an automatic slot valve was used for pressure regulation (2). Next, high-frequency power is applied from the high-frequency power source to the upper electrode 2 to start discharge between the lower electrode 3 holding the substrate (3) and leave for 10 seconds until the plasma discharge stabilizes, and then silicon nitride. Reaction gas A required for film formation
(Monosilane, nitrogen gas) was introduced for 60 seconds to deposit a thin film of a silicon nitride film on the substrate to a thickness of 400 nm (4).

After that, the introduction of the material gas A is stopped to finish the deposition of silicon nitride on the substrate (5), and at the same time, the discharge state is maintained in order to stabilize the discharge before the formation of the amorphous silicon film. As it is, material gas B
Hydrogen gas (discharge gas B), which is a constituent element gas of (monosilane), was introduced and pressure was adjusted. (6). At this time, the power applied to the electrode plate, the pressure adjustment set value, and the interelectrode distance setting may be changed as necessary. To continuously deposit amorphous silicon, adjust the pressure setting value to 150-
It is desirable that the pressure is 300 Pa.

After the discharge for 10 seconds, the introduction of the material gas B (monosilane) was started (7), and the discharge was continued for 60 seconds to 3
Amorphous silicon with a film thickness of 00 nm was deposited.

After that, the power supply from the high-frequency power source was stopped to stop the discharge, and at the same time, the supply of the material gas B was stopped to stop the deposition of the amorphous silicon film on the substrate (8). Here, the film is evacuated after the film formation until the ultimate vacuum reaches, for example, 10 Pa or less of the medium vacuum in the film formation chamber (9), and the substrate is unloaded from the film formation chamber (10). The time required for evacuation after film formation is 10 seconds using a dry pump having a sufficient evacuation capacity.

As described above, according to the film forming method of this embodiment, the conventional film forming method requires two film forming chambers.
It took 0 seconds to perform continuous film formation in only one film forming chamber, and the total time required for film formation could be 180 seconds.

Further, in this example, the discharge time in the gas containing no monosilane was set to 10 seconds or more, so that the influence of impurities could always be kept to a minimum and managed.

Further, as described above, discharge (plasma state)
Since the monosilane was introduced after the stabilization, the film formation was not performed in the initial plasma state shown in FIG. 7, and good initial deposition film quality was obtained.

Therefore, according to the method of this embodiment,
The quality of the interfacial film of the deposited film becomes good, and a thin film transistor with good characteristics can be obtained.

In this embodiment, the film formation of silicon nitride and amorphous silicon is carried out in a single film forming chamber, but by the same procedure as in the above embodiment, three or more thin films in a single film forming chamber are formed. Can be continuously formed. Note that in the case of continuously forming various thin films in this way, the discharge may be temporarily stopped after the formation of one thin film and prior to the formation of a different type of thin film. May be.

The discharge with the discharge gas and the discharge with the reaction gas may be intermittent within 1 second. Further, the high frequency power may be pulsed intermittent power.

In summary, in this embodiment, a plurality of film formations are carried out in the same film formation chamber, and a discharge gas that does not contribute to film formation is introduced as a discharge gas among the thin film forming reaction gases, and the plasma is adjusted after the pressure adjustment. In this state, the surface to be formed is cleaned, and this clean discharge gas is subsequently used as a part of the film forming reaction gas.

In this embodiment, a discharge gas other than monosilane, which is not capable of forming a thin film by itself, is discharged before the thin film is formed, and after a predetermined time elapses, monosilane is introduced into the discharge space while continuing the discharge. Since the thin film formation is started, the substrate is exposed to the activated atmosphere at the time of starting the discharge, and it is not necessary to perform high vacuum exhaust by the wide area turbo molecular pump before and after the film formation. It is possible to form a thin film in a clean atmosphere, and it is possible to form a good thin film in a short time without inclusion of impurities in the initial stage of thin film formation. That is, the film forming chamber may be maintained at a medium vacuum of several Pa to 300 Pa, a pump capable of reaching a high vacuum is unnecessary, and an exhaust system such as a dry pump is sufficient.

Further, in the conventional thin film forming method, 40
120 seconds for forming a 0 nm thick silicon nitride thin film, 300
While it took 360 seconds to form the amorphous silicon thin film having a thickness of nm, the productivity was well improved in 60 seconds in each case. That is, according to the present invention, since the deposition is started from a stable plasma state, the film quality at the initial stage of deposition and the film quality after that are the same, so that it is possible to substantially improve the growth rate of the film. Further, in controlling the film thickness, good reproducibility of the film thickness can be obtained only by controlling the supply time of monosilane. In the case of manufacturing a thin film transistor according to this embodiment, it takes 840 seconds in the conventional thin film forming method using two film forming chambers, whereas it takes 1 time in using one film forming chamber.
It only takes 80 seconds.

Example 2 Using the parallel plate electrode type CVD apparatus shown in FIG.
A channel etching TFT (inverted stagger type) shown in FIG. 3 was manufactured on a 0 mm × 470 mm glass substrate using the film forming conditions shown in Table 1 and a known etching technique.

[0050]

[Table 1] In FIG. 3, 10 is a glass substrate, 11 is a metal, and 12
Is a gate silicon nitride film, 13 is an amorphous silicon film, 14 is a doped amorphous silicon film, and 15 is a silicon nitride film. In this embodiment, the present invention is used for forming a gate silicon nitride film-amorphous silicon film-n ⁺ silicon film.

Example 3 Using the parallel plate electrode type CVD apparatus shown in FIG.
On a 0 mm × 470 mm glass substrate, the channel insulation type TFT (inverted stagger type) shown in FIG. 4 was manufactured under the film forming conditions shown in Table 2 and a known etching technique.

[0052]

[Table 2] In FIG. 4, reference numeral 15 is a silicon nitride film, and the other portions indicated by the same reference numerals as those in FIG. 3 are the same portions as those in FIG. In this embodiment, the present invention is used for forming a gate silicon nitride film and a gate silicon nitride film-amorphous silicon film-channel insulating silicon nitride film.

Example 4 Using the parallel plate electrode type CVD apparatus shown in FIG.
The positive staggered TFT shown in FIG. 5 was manufactured on a 0 mm × 470 mm glass substrate using the film forming conditions shown in Table 3 and a known etching technique.

[0054]

[Table 3] In FIG. 5, reference numeral 16 is a polycrystalline silicon film, and the other parts indicated by the same reference numerals as those in FIG. 3 are the same parts as those in FIG.

In this embodiment, 16 is a polycrystalline silicon film, but it may be amorphous silicon. In this embodiment, the present invention is used for forming a polycrystalline silicon film-silicon nitride film.

[0056]

According to the thin film forming method of the present invention, the substrate to be treated and the film forming chamber are exposed to the activated atmosphere at the time of the start of discharge and cleaned, so that the film can be cleaned before and after the film formation. Therefore, it is not necessary to perform high vacuum exhaustion with a wide area turbo molecular pump, and it is possible to form a good thin film free from impurities in the initial stage of thin film formation in a short time.

Further, since it is sufficient to maintain a vacuum of about several Pa to 300 Pa in the film forming chamber, a pump capable of reaching a high vacuum is unnecessary, which lowers the apparatus cost, downsizes the apparatus, and improves productivity. It is possible to improve.

Further, since a gas which has no film forming ability by itself is used as the discharge gas and the supply of the reaction gas is switched while maintaining the plasma state, thin film formation is performed in the plasma unstable state at the initial stage of discharge. Instead, uniform film formation can be performed at the initial stage of film formation and thereafter.
Furthermore, since the component gas that constitutes the reaction gas is used as the discharge gas, it does not affect the characteristics even if it is taken into the film. Particularly, the interface of the semiconductor thin film is treated with hydrogen gas plasma. In that case, there is an advantage that Si—H is formed at the interface and the characteristics of the semiconductor device obtained on the contrary are improved.

Furthermore, according to the present invention, it is possible to continuously form various kinds of laminated thin films in a single film forming chamber, which is more efficient than the conventional thin film forming method. A film can be formed and productivity can be improved. In this case, since the substrate after the thin film formation is always placed in an activated gas atmosphere, even if a plurality of different film types are continuously formed in a single film forming chamber, impurities in each film type are not formed. It is possible to obtain good interfacial separation characteristics without the inclusion of

Further, the film thickness can be controlled only by controlling the supply time of the gas involved in forming the thin film, so that the reproducibility of the film thickness is improved.

[Brief description of drawings]

FIG. 1 is a diagram conceptually showing a CVD apparatus used in an example of the present invention.

FIG. 2 is a flowchart of an embodiment of the present invention.

FIG. 3 is a diagram schematically showing a channel etching type TFT manufactured by using the present invention.

FIG. 4 is a channel-insulated T manufactured using the present invention.
The figure which shows FT typically.

FIG. 5 is a diagram schematically showing another channel etching type TFT manufactured by using the present invention.

FIG. 6 is a flowchart of a conventional thin film forming method by a parallel plate plasma CVD method.

FIG. 7 is a graph showing changes in reflected waves after power is applied.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Film-forming chamber, 2 ... Upper electrode, 3 ... Lower electrode, 4 ... Heater, 5 ... High frequency power supply 6 ... Substrate, 7 ... Gas inlet, 8 ... Exhaust port, 10 ... Glass substrate, 11 ... Metal, 12 ... Gate silicon nitride film, 1
3 ... Amorphous silicon film, 14 ... Doped amorphous silicon film, 15 ... Silicon nitride film 16 ... Polycrystalline silicon film

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[Procedure amendment]

[Submission date] March 6, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0052

[Correction method] Change

[Correction content]

[0052]

[Table 2] In FIG. 4, reference numeral 16 is a channel insulating silicon nitride film, and the other portions indicated by the same reference numerals as those in FIG. 3 are the same portions as the respective portions in FIG. In this embodiment, the present invention is used for forming the gate silicon nitride film 11, the gate silicon nitride film 12, the amorphous silicon film 13 and the channel insulating silicon nitride film 14.

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 4

[Correction method] Change

[Correction content]

[Figure 4]

Claims (10)

[Claims] 1. A substrate to be treated is placed in a vacuum container having a gas inlet, and 1 is placed in the vacuum container through the gas inlet.
A method of forming a thin film of a reaction product of the reaction gas on the substrate to be processed by generating plasma by applying high-frequency power to the reaction gas while introducing one kind or two or more kinds of reaction gas, Prior to the introduction of the reaction gas, a component gas constituting the reaction gas which does not substantially have the ability to form a thin film by itself, or one or more gases contained in the two or more reaction gases, While introducing a discharge gas consisting of a gas that does not substantially have the ability to form a thin film by itself, a high-frequency power is applied to the discharge gas to generate plasma to perform pretreatment, and then a substantially plasma state is set. A thin film forming method, characterized in that the reaction gas is introduced in place of the discharge gas while being maintained to form a thin film on the substrate to be processed. 2. A substrate to be processed is arranged on one of the parallel plate electrodes in a vacuum container having a gas inlet and a parallel plate electrode inside, and a plurality of thin films are formed on the substrate to be processed. In the thin film forming method to do, from the gas inlet,
A step of applying high-frequency power to the parallel plate electrodes while introducing a discharge gas to cause plasma discharge, and introducing a reaction gas instead of the discharge gas while substantially maintaining the discharge on the substrate A step of forming a thin film of a reaction product of a reaction gas, wherein at least one step of forming the thin film forms a semiconductor thin film of a reaction product using one or more kinds of reaction gases. The gas for discharge introduced immediately before this step is a component gas constituting the above reaction gas which does not substantially have the ability to form a thin film under plasma discharge by itself, or two or more kinds thereof. The method for forming a thin film, characterized in that the thin film forming method comprises one or more kinds of gas included in the reaction gas of 1., which itself has substantially no ability to form a thin film under plasma discharge. 3. The thin film forming method according to claim 1, wherein the semiconductor thin film is made of silicon and a non-oxygen element, and the discharge gas is made of the non-oxygen gas. 4. The thin film forming method according to claim 2, wherein the semiconductor thin film is made of silicon and the discharge gas is hydrogen. 5. A plasma discharge time when introducing the discharge gas is within a range of 0.1 to 0.4 when the plasma discharge time when introducing the reaction gas is 1. Any one of claims 1 to 4 characterized in that
The thin film forming method described. 6. The reaction gas is introduced with the gas pressure and the discharge power kept constant when the reaction gas is introduced instead of the discharge gas while maintaining the plasma discharge. Item 6. A thin film forming method according to any one of items 1 to 5. 7. The thin film forming method according to claim 2, wherein the plurality of thin films are thin films made of silicon nitride-amorphous silicon. 8. The thin film forming method according to claim 2, wherein the plurality of thin films are thin films made of silicon nitride-amorphous silicon-silicon nitride. 9. The method for forming a thin film according to claim 8, wherein the thin films of the plurality of layers are silicon oxide-silicon nitride-amorphous silicon-silicon nitride thin films forming an amorphous silicon TFT (inverted stagger type). 10. The reaction gas is silane gas, hydrogen gas,
One or two selected from nitrogen gas and ammonia gas
10. The method for forming a thin film according to claim 2, wherein the discharge gas comprises one or more kinds, and the discharge gas includes one kind or two or more kinds selected from hydrogen gas, nitrogen gas and ammonia gas.