JP2003273094A - Cvd apparatus and method for performing post-treatment process after film formation in the cvd apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a CVD apparatus which can fully cope with post-treatment process needing sufficient plasma after film formation, by preventing a substrate during the film formation from being exposed directly with the plasma, not only preventing back-diffusion to a plasma generation space of material gas during the film formation, but also properly regulating the conductance between the plasma generation space and a film formation treating space, and to provide a method for performing the post-treatment process after the film formation in the CVD apparatus. <P>SOLUTION: A shielding plate, provided with through-holes corresponding to positions where a plurality of partition walls of a conductive partition wall plate exist through-holes and holes corresponding to positions where diffusion holes of the shielding plate through-holes exist, respectively, is arranged separably and contactably to the partition wall on the side of the film formation and treating space. In this way, the conductance between the plasma generation space and the film formation and treating space can be regulated by contacting and separating the shielding plate to and from the partition wall plate. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemical vapor deposition apparatus (hereinafter referred to as "CVD apparatus"), and particularly to a CVD method suitable for film formation on a large flat panel substrate.
The present invention relates to a method of performing a post-treatment process after film formation in an apparatus and a CVD apparatus.

[0002]

2. Description of the Related Art As a method for manufacturing a large-sized liquid crystal display, conventionally, a method using a high temperature polysilicon type TFT (thin film transistor) and a method using a low temperature polysilicon type TFT are known. High temperature polysilicon type TF
In the manufacturing method using T, a quartz substrate that can withstand a high temperature of 1000 ° C. or higher is used in order to obtain a high quality oxide film. On the other hand, in the production of a low temperature polysilicon type TFT, since a normal glass substrate for TFT is used, it is necessary to form a film in a low temperature environment (eg 450 ° C. or lower). The method of manufacturing a liquid crystal display using the low temperature polysilicon type TFT has the advantage that it is not necessary to use a special substrate and that the film forming conditions can be set easily. Is expanding.

In the production of a liquid crystal display using a low temperature polysilicon type TFT, plasma CVD is used to form a suitable silicon oxide film as a gate insulating film at a low temperature. When forming a silicon oxide film by this plasma CVD, silane, tetraethoxysilane (TEOS), etc. are used as a typical material gas.

When a silicon oxide film is formed by plasma CVD using silane or the like as the material gas, the conventional plasma CVD apparatus introduces the material gas and oxygen into the front space of the substrate to generate the material gas. Plasma is generated with a mixed gas of oxygen, and the substrate is exposed to the plasma to form a silicon oxide film on the surface of the substrate. As described above, in the conventional plasma CVD apparatus, the material gas is configured to be directly supplied into the plasma generated in the plasma CVD apparatus. Therefore, according to the configuration of the conventional plasma CVD apparatus, high-energy ions are incident on the film formation surface of the substrate from the plasma existing in the front space of the substrate, and the silicon oxide film is damaged, so that the film characteristics are deteriorated. There was the problem of getting worse. Further, since the material gas is directly introduced into the plasma, the material gas and the plasma violently react with each other to generate particles, which reduces the yield.

Therefore, in order to solve the above problem, an attempt was made to improve the conventional remote plasma type CVD apparatus, and a new CVD apparatus was proposed according to Japanese Patent Application Laid-Open No. 2000-345349.

The CVD apparatus proposed in Japanese Patent Laid-Open No. 2000-345349 generates plasma in a vacuum container to generate neutral excited active species (herein referred to as "active species"). It is an apparatus that performs film formation processing on a substrate with active species and material gas. The vacuum container is provided with a conductive partition plate that separates the interior of the vacuum container into two chambers.

Of these two chambers, the inside of one chamber is formed as a plasma generation space in which a high frequency electrode is arranged, and the inside of the other chamber is a film formation processing space in which a substrate holding mechanism for mounting a substrate is arranged. Formed as. Further, a plurality of partition plate through-holes are formed in the partition plate so as to allow the plasma generation space and the film formation processing space to pass therethrough. The partition plate is also
It has an internal space that is isolated from the plasma generation space and communicates with the film formation processing space through a plurality of diffusion holes. Material gas is supplied to the internal space from the outside, and the material gas supplied to the internal space is introduced into the film formation processing space through a plurality of diffusion holes. The active species generated in the plasma generation space are introduced into the film formation processing space through the plurality of partition plate through holes formed in the partition plate. The sizes (length, diameter, etc.) of the partition plate through holes and the diffusion holes are designed to prevent back diffusion of the material gas into the plasma generation space.

This avoids the problems of the conventional plasma CVD apparatus, such as plasma damage caused by direct exposure of the substrate during film formation to plasma and generation of particles due to excessive decomposition of the reactive gas. You can
Furthermore, it was possible to prevent the backflow of the material gas into the plasma generation space during film formation.

[0009]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The CVD apparatus having the structure proposed in U.S. Pat. No. 4,345,349 is excellent in that the substrate during film formation is not directly exposed to plasma, and the back diffusion of the material gas into the plasma generation space during film formation can be prevented. The features can be realized.

On the other hand, on the other hand, the partition plate has a structure that blocks the introduction of plasma in the step requiring sufficient plasma after the film formation. In other words, due to the structure of the partition plate, the conductance between the plasma generation space and the film formation processing space is fixed by the diameters and lengths of the plurality of partition plate through holes formed in the partition plate. It is becoming difficult to deal with the process.

Specifically, after the film formation step in which the introduction of the material gas is blocked, in order to improve, for example, the electrical characteristics of the formed thin film, the thin film immediately after the film formation is irradiated with plasma or radicals. Modification treatment such as treatment (promoting appropriate oxidation) may be performed, but in this case, since it affects productivity (the number of sheets processed per unit time), treatment in a short time is required and sufficient Irradiation of plasma or radicals into the film formation processing space is required.

[0012] Usually, after a predetermined number of film forming processes have been performed, the film adhered to other parts than the substrate in the film forming chamber, for example, the substrate holding mechanism or the inner wall of the vacuum container on the film forming process side is peeled off. In order to prevent particles from being generated, a cleaning step, which is a removing operation, is performed. Cleaning operations should be exposed to a more active atmosphere. Therefore,
In order to improve the cleaning efficiency, that is, to improve the cleaning speed, it is better to introduce the plasma in the plasma generation space into the film formation processing space.

In the present specification, a modification process such as an oxidation accelerating process for the thin film immediately after the film formation described above, and
The cleaning process (removal of the silicon oxide film) is generically called a post-treatment process.

Therefore, the above-mentioned Japanese Unexamined Patent Publication No. 2000-34.
In the CVD apparatus having the structure proposed in No. 5349, if it becomes possible to sufficiently introduce plasma or the like into the film formation processing space in the post-treatment step that requires sufficient radicals or plasma after the film formation step, Not only can the substrate during film formation be prevented from being directly exposed to plasma, but also the back diffusion of the material gas into the plasma generation space during film formation can be prevented.
It is possible to provide a CVD apparatus that can sufficiently support a process that requires sufficient plasma after film formation.

Therefore, according to the present invention, the substrate during film formation can be prevented from being directly exposed to plasma, and not only the back diffusion of the material gas into the plasma generation space during film formation but also the formation of the plasma generation space can be prevented. Perform a post-deposition process in a CVD apparatus and a CVD apparatus that can appropriately adjust the conductance with the film processing space and can sufficiently cope with a post-processing step that requires sufficient plasma after film formation It is intended to provide a way.

[0016]

In order to solve the above-mentioned problems, the CVD apparatus proposed by the present invention is constructed as follows.

The CVD apparatus of the present invention is to generate plasma in a vacuum container to generate excited active species, and to form a film on a substrate with the active species and the material gas.

In this CVD apparatus, the inside of the vacuum container is separated into two chambers by a conductive partition plate, and one of the two separated chambers has a plasma generation space in which a high frequency electrode is arranged. The inside of the other chamber is formed as a film forming processing space in which a substrate holding mechanism for mounting the substrate is arranged. The partition plate has a plurality of partition plate through holes that allow the plasma generation space and the film formation processing space to pass therethrough, and is separated from the plasma generation space and has the film formation processing space and a plurality of diffusion holes. It has an internal space communicating with it. Then, a material gas is supplied to the internal space from the outside, and the material gas is introduced into the film formation processing space through the plurality of diffusion holes. On the other hand, active species generated in the plasma generation space by applying high-frequency power to the high-frequency electrode to generate plasma discharge in the plasma generation space are introduced into the film formation processing space through the plurality of partition plate through holes of the partition plate. . Then, the film formation is performed on the substrate by the active species and the material gas thus introduced in the film formation processing space.

The present invention is characterized in that, in such a CVD apparatus, a shield plate which can freely come into contact with and separate from the partition plate is arranged on the film formation processing space side.

That is, the CVD apparatus of the present invention is disclosed in
In the CVD apparatus of the structure proposed in 000-345349, the conductance between the plasma generation space and the film formation processing space, which is fixed by the diameters and lengths of the plurality of partition plate through holes formed in the partition plate, By arranging a shield plate that can be separated from and contacted with the partition plate on the film formation processing space side, the adjustment can be appropriately performed.

In the mechanism for allowing the shield plate to be detachable from the partition plate, the substrate holding mechanism is movable in a direction toward and away from the partition plate, and the shield plate is held by the movable substrate. This can be realized by a structure attached to the mechanism or a structure in which a drive mechanism is attached to the shield plate itself so that the shield plate can be moved toward and away from the partition plate.

Here, from the viewpoint of maintaining good uniformity of the thin film to be formed, the shielding plate has a surface of the shielding plate facing the partition plate and a surface of the partition plate facing the shielding plate. It should be possible to keep the parallel state at all times and to be able to approach the partition plate so as to be in close contact with the partition plate, and to be able to move in the direction away from the partition plate from being in close contact with the partition plate. desirable.

In the CVD apparatus of the present invention, the shield plate is
A plurality of diffusion walls of the partition plate are provided at a position of the partition plate facing the plurality of partition plate through holes, and a convex portion fitted in a concave portion of the partition plate through hole facing the shield plate. A hole is provided at a position facing the hole, a shield plate through hole is provided in the convex portion, and the shield plate is in close contact with the partition plate,
When the convex portion is fitted into the concave portion, the plasma generation space and the film formation processing space may be communicated with each other only by the partition plate through hole and the shielding plate through hole. .

With this configuration, when the shield plate is brought into close contact with the partition plate, the partition plate through hole and the shield plate through hole provided in the convex portion of the shield plate form an integral through hole, and the plasma generation space is formed. And the film forming processing space are communicated with each other. Therefore, if the film formation process is performed on the substrate when the shield plate is in close contact with the partition plate in this way, the material during film formation proposed by the CVD apparatus of Japanese Patent Laid-Open No. 2000-345349 is proposed. This is advantageous because a structure that prevents back diffusion of gas into the plasma generation space can be easily realized.

That is, when the shield plate is in close contact with the partition plate, the convex portion of the shield plate is fitted in the recess portion of the through hole of the partition plate on the side facing the shield plate, and generated in the plasma generating space. The activated species are introduced from the plasma generation space to the film formation processing space through the shield plate through hole having a structure for preventing the back diffusion of the material gas into the plasma generation space. Therefore,
The conductance between the plasma generation space and the film formation processing space is determined only by the shape of the shield plate through hole. Therefore, when the gas flow velocity in the through hole of the shield plate is u, the effective length of the through hole of the shield plate (the length of the minimum diameter portion) is L, and the material gas (silane gas or the like) and the reaction gas (here , And the mutual gas diffusion coefficient with oxygen gas for plasma generation) is set to D so that the condition of uL / D> 1 is satisfied so that the material gas is reverse to the plasma generation space during film formation. Diffusion can be prevented. When introducing a sufficient amount of radicals or plasma into the film formation processing space as in the post-treatment process after the film formation process, the shielding plate that was in close contact with the partition plate during the film formation process as described above is used. Away from the partition plate,
The fitting state of the convex portion of the shielding plate in the concave portion of the partition plate through hole facing the shielding plate is released. Then, the conductance between the plasma generation space and the film formation processing space can be freely adjusted by appropriately adjusting the distance that the shield plate separates from the partition plate.

In the above, the holes provided in the shielding plate at positions facing the plurality of diffusion holes of the partition plate are prepared by bringing the shielding plate into close contact with the partition plate to perform the film forming process as described above. Thus, the shielding plate does not hinder the introduction of the material gas from the diffusion holes of the partition plate.

When a sufficient amount of radicals or plasma is introduced into the film formation processing space after the film formation process as in the post-treatment process, the shield plate is separated from the partition plate to generate plasma as described above. It is desirable to increase the conductance between the space and the film formation processing space.

Therefore, the method of carrying out the post-treatment process after film formation in the CVD apparatus proposed by the present invention uses the above-described CVD apparatus of the present invention, and the conductive partition plate is set at the ground potential while being post-processed in the plasma generation space. Introduce gas for the treatment process,
While generating active species in the plasma generation space by applying high-frequency power to the high-frequency electrode to generate plasma discharge, the shielding plate is separated from the partition plate, in a state where the shielding plate is separated from the partition plate, The generated active species are introduced from the plasma generation space into the film formation processing space through the plurality of partition plate through holes, and a post-treatment step after film formation is performed in the film formation processing space. is there.

In this case, as the gas for the post-treatment process,
When the post-treatment process is the reforming process, oxygen gas
Is a cleaning process, as a cleaning gas
NF _Three, SF₆Fluorine gas such as is used.

By doing so, the plasma, radicals and the like introduced from the plasma generation space side through the plurality of partition plate through holes of the partition plate are separated from the shielding plate and the partition wall as described above. A space between the plate and the barrier plate, the plurality of holes provided in the shield plate at positions facing the plurality of diffusion holes, and the plurality of shield plate through holes to reach the film formation processing space. You can That is, since the conductance between the plasma generation space and the film formation processing space is increased, it is possible to introduce a sufficient amount of plasma, radicals or the like into the film formation processing space.

In consideration of doing this in the post-treatment process, the diameter of the holes in the shielding plate is sufficiently larger than the diameter of the diffusion holes in the partition plate so that plasma and the like can easily pass through. It is advantageous to make it large.

According to the CVD apparatus of the present invention, the active species generated in the plasma generation space correspond to the plurality of partition plate through holes formed in the partition plate during the film forming process and each of them. It is introduced into the film formation processing space through the shield plate through hole of the shield plate.

Further, according to the CVD apparatus of the present invention and the method of performing the post-treatment step, the partition plate and the shield plate, which are in close contact with each other during the film forming process, are driven from the partition plate by driving the shield plate holding mechanism. By separating them, the conductance between the plasma generation space and the film formation processing space can be increased. Therefore, it is necessary to introduce a sufficient amount of radicals or plasma into the film formation processing space in a reforming process or a cleaning process (removal of the silicon oxide film) for promoting sufficient oxidation of the thin film immediately after film formation. It can cope with the process enough.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to FIG. 1 of the accompanying drawings.

The CVD apparatus of the present invention is to generate plasma in a vacuum container to generate excited active species, and to form a film on a substrate with the active species and the material gas. Here, the vacuum container has a structure in which the upper container 12 and the lower container 11 are joined.

First, the positional relationship between the partition plate 15 and the shielding plate 16 is set to the state at the time of film formation shown in FIG. 3B, silane gas (SiH ₄ ) is used as the material gas, and oxygen (O) is used as the plasma generating gas.
₂ ) is used to form a silicon oxide film (Si
The case of forming an O ₂ ) thin film will be described.

The inside of the vacuum container is separated into two chambers by a conductive partition plate 15. Of the two separated chambers,
The inside of one chamber is formed as a plasma generation space 17 in which the high-frequency electrode 24 is arranged, and the inside of the other chamber is formed as a film formation processing space 18 in which a substrate holding mechanism 19 for mounting a substrate is arranged.

The partition plate 15 has a plurality of partition plate through holes 31 through which the plasma generation space 17 and the film formation processing space 18 pass.
And an internal space 28 that is isolated from the plasma generation space 17 and communicates with the film formation processing space 18 via a plurality of diffusion holes 33.

The glass substrate 10 is loaded into a vacuum container by a transfer robot (not shown) and mounted on the substrate holding mechanism 19. In the substrate holding mechanism 19, the heater 22 is energized and held at a predetermined temperature in advance. The inside of the vacuum container is evacuated by the exhaust path 14, decompressed, and maintained in a predetermined vacuum state.

A material gas introduction pipe 3 in which a material gas, for example, silane gas, is connected to a material gas supply system (not shown)
6 is introduced into the internal space 28 of the partition plate 15, and this is introduced into the film formation processing space 18 through the plurality of diffusion holes 33. That is, the silane gas is first introduced into the internal space 28.
Of the uniform plate 35, is uniformly diffused by the uniform plate 35, moves to the lower part, and then is directly introduced into the film formation processing space 18 through the diffusion holes 33, that is, without being brought into contact with plasma. .

On the other hand, oxygen gas is introduced into the plasma generating space 17 of the vacuum container (upper container 12) through the oxygen gas introducing pipe 27a.

Here, high-frequency power is applied to the high-frequency electrode 24 having the plurality of electrode holes 25 from the power-introducing rod 37 which is covered with the insulator 39 and insulated from other metal parts. . Oxygen plasma 23 is generated around the high frequency electrode 24 by generating a plasma discharge in the plasma generation space 17 by this high frequency power.
As a result, radicals (excited active species) that are neutral excited species are generated and introduced into the film formation processing space 18 through the plurality of integrated through holes of the partition plate 15 and the shielding plate 16 that are in close contact with each other. It

Therefore, in the film formation processing space 18, the glass substrate 10 is treated with the active species and the material gas introduced as described above.
A thin film is formed by depositing silicon oxide on the surface of.

From the viewpoint of improving the assembling property of the vacuum container, the vacuum container 12 forms the plasma generating space 17 in the upper container 12.
And a lower container 11 that forms a film formation processing space 18. When the upper container 12 and the lower container 11 are combined to form a vacuum container, the conductive material fixing portion 26 is provided at a position between them.
c has a desired specific thickness and has an internal space 28
The partition plate 15 in which is formed is provided in a horizontal state.

The high-frequency electrode 24 has a peripheral side surface,
The insulating member 26a interposed between the upper container 12 and the upper container 12 is attached such that the lower end surface of the peripheral portion thereof contacts the lower insulating member 26b.

In this way, the plasma generation space 17 and the film formation processing space 18 which are isolated from each other are formed above and below the partition plate 15 and the shielding plate 16.

The partition plate 15 and the shielding plate 16 made of a conductive material are formed in a rectangular shape in plan view. The peripheral edge of the partition plate 15 is arranged so as to be pressed by the conductive material fixing portion 26c to form a sealed state, and the partition plate 15 and the shielding plate 16 are in close contact with each other as shown in FIG. 3 (b). When in the state, the partition plate 15 and the shielding plate 16 have the same ground potential 4 as the vacuum container via the conductive material fixing portion 26c.
Is kept at 1.

The glass substrate 10 includes the partition plate 15 and the shield plate 1.
It is arranged substantially parallel to 6 and its film forming surface (upper surface) faces the lower surfaces of the partition plate 15 and the shielding plate 16.

The potential of the substrate holding mechanism 19 is held at the ground potential 41, which is the same potential as the vacuum container (lower container 11).

Plasma is generated from the outside on the insulating member 26a.
Introduce oxygen gas into plasma 17 for plasma generation
Oxygen gas introduction pipe 27a, during the cleaning process,
NF _Three, F_Two, SF₆, CF4, C_TwoF₆, C_ThreeF_Three
Cleaning gas introduction pipe for introducing fluorinated gas such as
27b are provided.

Inside the vacuum container, a plasma generation space 17 and a film formation processing space 18 are formed by a partition plate 15 and a shield plate 16.
However, the shielding plate 16 is formed with a plurality of shielding plate through holes 32 satisfying a predetermined condition, and the partition plate 15 and the shielding plate 16 are in a close contact state as shown in FIG. 3B. At this time, the plasma generation space 17 and the film formation processing space 18 are connected only through the partition plate through hole 31 and the shielding plate through hole 32 which are integrated.

In the CVD apparatus of the present invention, the partition plate 1
A shield plate 16 that can be moved in and out of contact with the film 5 is disposed on the film formation processing space 18 side.

In the embodiment shown in FIG. 1, the substrate holding mechanism 1
9 is movable in the vertical direction (arrow 42) in FIG. 1 by a drive unit (not shown).

The baffle plate 16 is arranged in the film forming processing space 18 between the glass substrate 10 mounted on the substrate holding mechanism 19 and the partition plate 15, and the embodiment shown in FIG. In FIG. 3, the substrate holding mechanism 19 is attached to the outer peripheral portion of the substrate holding mechanism 19 via a plurality of supports 20.

In the embodiment shown in FIG. 1, a plurality of supports 20 whose upper end side is fixed to the shielding plate 16 respectively pass through the springs 21, penetrate the substrate holding mechanism 19, and are movable in the vertical direction. It is said that. Spring 21
1, the shield plate 16 and the support body 20 are subjected to an upward force in FIG. 1, and the substrate holding mechanism 19 is moved far away from the partition plate 15 as shown in FIG. At the position, the shield plate 16 is placed at a predetermined distance so that the downward force given by the weight of the shield plate 16 and the support 20 and the upward force generated by the elastic force of the spring 21 are balanced. It comes to be located on the upper side apart from.

At this time, the shield plate 16 is attached to the substrate holding mechanism 19
A structure is adopted in which the shield plate 16 is interlocked with the substrate holding mechanism 19 while being fixed to the upper ends of the plurality of supports 20 standing upright on the outer peripheral portion of the substrate while keeping a constant distance from the substrate holding mechanism 19. You can also do it.

As shown in FIG. 2, the shield plate 16 is not interlocked with the substrate holding mechanism 19, and an independent drive mechanism (not shown) for moving the shield plate 16 in the vertical direction is adopted.
The substrate holding mechanism 19 may be fixed at a predetermined position, and the shield plate 16 may be movable in the vertical direction (arrow 43) in FIG. 2 independently of the substrate holding mechanism 19.

In short, as shown in FIG. 3B, the shield plate 16 is in close contact with the partition plate 15, and as shown in FIGS. 1, 2 and 3A, the shield plate 16 is a partition wall. Board 15
Various structures and drive mechanisms can be adopted as long as the shielding plate 16 can move in a direction approaching the partition plate 15 and a direction away from the partition plate 15 between a state in which the partition plate 15 is away from the partition plate 15.

FIGS. 3 (a) and 3 (b) are partially enlarged schematic views showing the internal structures of the partition plate 15 and the shelter plate 16 as seen from the cross-sectional direction.

An internal space 28 is formed in the partition plate 15. The internal space 28 is a space for dispersing the material gas and uniformly supplying it to the film formation processing space 18.
The material gas introduction pipe 36 is arranged so as to be connected to the material gas supply system (not shown) from the side of the partition plate 15. A plurality of diffusion holes 33 for supplying a material gas to the film formation processing space 18 are formed on the lower surface of the partition plate 15 on the film formation processing space 18 side. The inner space 28 is divided into an upper space and a lower space by a uniform plate 35, and a material gas introduction pipe 36 for introducing a material gas is connected to the upper part of the inner space 28. That is, the silane gas or the like, which is the material gas, is introduced into the upper side of the internal space 28, reaches the lower side of the internal space 28 through the holes of the uniform plate 35, and further diffuses holes 33.
Through which they are uniformly diffused into the film forming processing space 18.

The partition plate through hole 31 is formed in the plasma generation space 1
Excited species (radicals) generated in 7 are holes that pass into the film formation processing space 18 where they can contact the material gas for the first time to proceed with the reaction.

On the side of the partition plate through hole 31 facing the shield plate 16, there is formed a recess 30 for gradually increasing the opening diameter.

On the other hand, the shield plate 16 is provided with a convex portion 29 fitted in the concave portion 30 at a position facing the plurality of partition plate through holes 31 of the partition plate 15. A shield plate through hole 32 is provided in the convex portion 29, and when the shield plate 16 is in close contact with the partition plate 15 and the convex portion 29 is fitted in the concave portion 30, as shown in FIG. In addition, an integral through hole is formed by the partition plate through hole 31 and the shielding plate through hole 32, and the plasma generation space 17 and the film formation processing space 18 are communicated with each other.

In the CVD apparatus of the present invention, FIG.
(B) As shown in the figure, it is desirable to perform the film forming process on the substrate in a state where the shielding plate 16 is in close contact with the partition plate 15.
This is because the shielding plate 16 is closely attached to the partition plate 15 and the protrusion 29
Is fitted in the recess 30 and the plasma generation space 17 and the film formation processing space 18 are communicated with each other only by the partition plate through hole 31 and the shielding plate through hole 32. This is because it is possible to easily realize a configuration in which back diffusion of the material gas into the plasma generation space 17 is unlikely to occur.

That is, when the gas flow velocity in the shield plate through hole 32 is u, the distance that the gas passes, that is, the effective length of the shield plate through hole 32 (the length of the minimum diameter portion) is L.
(FIG. 3A), when the mutual gas diffusion coefficient between the material gas (silane gas or the like) and the reaction gas (oxygen gas for plasma generation or the like) is D, the condition of uL / D> 1 is satisfied. By doing so, it is possible to prevent the back diffusion of the material gas into the plasma generation space 17 during film formation.

Therefore, it is preferable that the diameter of the shield plate through hole 32 is set so as to satisfy this condition.

Next, among the methods for carrying out the post-treatment process of the present invention carried out using the above-described CVD apparatus of the present invention, a cleaning method using a cleaning gas as a gas for the post-treatment process will be described. In the cleaning method illustrated below, NF is used as the cleaning gas.
_It uses ₃ gases.

The timing for cleaning is appropriately set after the film formation based on a predetermined predetermined time, or a predetermined number of processed substrates.

In this cleaning step, the introduction of the raw material gas such as silane into the film formation processing space 18 is shut off, and the oxygen gas introduced from the oxygen gas introduction pipe 27a during the film formation is removed from the cleaning gas introduction pipe 27b. By switching to the cleaning gas (fluorine gas) to be introduced, the radicals to be used are different from those used in the above-described film formation, and mechanically, the relative positions of the shielding plate 16 and the partition plate 15 are different. The relationship is the positional relationship at the time of film formation (the partition plate 15
And the shielding plate 16 are in close contact with each other), and other operations are performed in substantially the same manner as the above-described film forming operation.

That is, the CVD apparatus cleaning method of the present invention is performed as follows. The partition plate 15 made of a conductive material is kept at the ground potential, NF ₃ gas is introduced into the plasma generation space 17 as a cleaning gas, and high frequency power is supplied to the high frequency electrode 24 so that the plasma generation space 17 is supplied with the high frequency electrode 24. Generates fluorine radicals.

At this time, during the film forming process, the shield plate 16 that was in close contact with the partition plate 15 is lowered to the substrate holding mechanism 19 side,
It is stopped in the state of FIG. Therefore, the fluorine radicals or the like generated in the plasma generation space 17 pass through the space between the partition plate 15 and the shielding plate 16 from the partition plate through hole 31 and the recess 30, and pass through the holes 34 of the shielding plate 16 and the shielding plate 16. Through hole 3
It is possible to pass through 2 and reach the film formation processing space 18.

In this way, the shielding plate 16 that was in close contact with the partition plate 15 as shown in FIG.
(A) By separating from the partition plate 15 as shown,
The conductance between the plasma generation space 17 and the film formation processing space 18 can be increased. Therefore, at the time of cleaning, it is possible to diffuse a sufficient amount of fluorine radicals or the like into the film forming processing space 18 in a wide range, thereby increasing the cleaning speed.

At this time, in order to further increase the cleaning speed, an inert gas such as Ar gas or oxygen gas may be mixed into the cleaning gas (NF ₃ ).

An example of specific set values of the cleaning method for the silicon oxide film of the present invention is as follows.

The high voltage applied to the high frequency electrode 24 of 60 MHz.
Frequency power 2KW, cleaning gas NF_ThreeFlow rate
200 cm in standard condition^Three/ Min (0.63g / mi
n) to promote dissociation of the cleaning gas.
r gas is 100 cm in standard state ^Three/ Min (0.18g
/ Min) was added. At this time, the pressure of the film formation processing space 18
The force was 16 Pa.

When a sufficient amount of radicals or plasma is introduced into the film forming process space 18 as in the cleaning process after the film forming process described above, the space between the plasma generating space 17 and the film forming process space 18 is increased. In order to increase the conductance, as shown in FIGS. 1, 2 and 3 (a), the shield plate 16
Is separated from the partition plate 15, it is advantageous in increasing conductance that the partition plate through hole 31 through which radicals and the like pass is larger. Therefore, the partition plate through hole 31 has a diameter of FIG. (B) As shown, the shield plate through hole 3
It is desirable to make it larger than 2.

This also applies to the holes 34 of the shield plate 16, and it is desirable to make the diameter sufficiently large so that a sufficient amount of radicals and plasma can easily pass through.

Further, when a reforming step, for example, an oxidation promoting treatment step for promoting sufficient oxidation of a thin film immediately after the formation of a silicon oxide film or the like is performed as the post-treatment step, the above-described film forming step is performed. After the completion, while the glass substrate 10 immediately after the film formation is held on the substrate holding mechanism 19, the introduction of the material gas through the material gas introduction pipe 36 is stopped,
On the other hand, the introduction of oxygen gas into the plasma generation space 17 through the oxygen gas introduction pipe 27a, the plasma generation space 1
Oxygen plasma is generated within 7. The oxygen plasma generated in the plasma generation space 17 in this way has a large conductance between the plasma generation space 17 and the film formation processing space 18, as in the cleaning step described above. To pass through the space between the partition plate 15 and the partition plate 15 that is separated from the partition plate 15 to pass through the holes 34 and the through holes 32 of the shield plate 16 and reach the film formation processing space 18. You can

The preferred embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to such embodiments, and within the technical scope grasped from the description of the claims. It can be changed into various forms.

For example, as described above, the diameters of the partition plate through holes 31 and the shielding plate through holes 32 are set in a good relationship, and when the shielding plate 16 is in close contact with the partition plate 15, the partition plate through holes are formed. An integral through hole is formed by 31 and the shield plate through hole 32, and the plasma generation space 17 and the film formation processing space 18 are formed.
If is communicated with, the convex portion 29 has the partition plate through hole 3
Even if the concave portion 30 is arranged on the side of the shield plate through hole 32, the partition plate 15 and the shield plate 1
As long as the adhesiveness is sufficiently ensured at the time of contacting with No. 6, both forms are substantially included in the technical scope of the present invention even if both plate members have no unevenness and the surfaces to be adhered are flat. Is understood.

In the embodiment, the high frequency electrode 24 having the plurality of electrode holes 25 is arranged in the plasma generating space 17, but for example, a normal parallel plate type in which the power electrode is arranged above the upper container 12 is used. , One or more microwave plasma sources, as well as one or more electron cyclotron resonance (ECR) plasma sources, dielectric junction plasma sources, and helicon wave plasma sources, as long as they can generate and maintain a plasma state, It goes without saying that it can be applied to any method.

Further, the case where the silicon oxide film is formed by using silane gas as the material gas and oxygen as the reaction gas has been described. However, by changing the material gas and the reaction gas, the nitride film, the fluoride film, and the carbon film are formed. It goes without saying that it can be applied to the above.

[0083]

According to the CVD apparatus of the present invention, by providing a movable shield plate in the film formation processing space, the space between the plasma generation space and the film formation processing space separated by the partition plate of the vacuum container is provided. The conductance can be changed appropriately according to the purpose of use.

That is, from the normal plasma-free film-forming state in which the substrate is prevented from being damaged, the shield plate is separated from the partition plate to increase the conductance, thereby facilitating introduction of plasma into the film-forming process space side. Since it can be applied to various processes such as improving the cleaning efficiency and plasma irradiation process using plasma itself (promoting appropriate oxidation) and film modification, the process margin including cleaning can be expanded. .

Therefore, according to the method of performing the post-treatment step in the CVD apparatus of the present invention, when performing a step requiring a more active atmosphere, a large amount of ions and active species are introduced into the film formation processing space. Therefore, it is possible to improve the cleaning rate and sufficiently accelerate the oxidation immediately after the formation of the silicon oxide film.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing the configuration of a first embodiment of the present invention.

FIG. 2 is a vertical sectional view showing the configuration of a second embodiment of the present invention.

FIG. 3 is a partially enlarged schematic view of the internal structure of the partition plate and the shielding plate as viewed from the cross-sectional direction, FIG. 3A is a diagram showing a state where the partition plate and the shielding plate are separated, and FIG. The figure showing the state where the partition plate and the shielding plate are in close contact with each other.

[Explanation of symbols]

10 glass substrates 11 Lower container 12 Upper container 13 Exhaust port 14 Exhaust mechanism 15 Partition plate 16 Shield 17 Plasma generation space 18 Film forming processing space 19 Substrate holding mechanism 20 Support 21 spring 22 heater 23 Oxygen plasma 24 high frequency electrodes 25 electrode holes 26a, 26b Insulation member 26c Conductive material fixing part 27a Oxygen gas introduction pipe 27b Cleaning gas introduction pipe 28 Internal space 29 convex 30 recess 31 Partition plate through hole 32 Shield plate through hole 33 Diffusion hole 34 holes 35 uniform plate 36 Material gas introduction pipe 37 Electric power introduction rod 38 gas piping 39 Insulator 41 Ground potential 42 and 43 arrows

Claims (3)

[Claims] 1. A CVD apparatus for generating plasma in a vacuum container to generate excited active species and forming a film on a substrate with the active species and a material gas, wherein the inside of the vacuum container is formed by a conductive partition plate. The chamber is separated into two chambers, and one of the two chambers is a plasma generation space in which a high-frequency electrode is arranged, and the other chamber is provided with a substrate holding mechanism for mounting the substrate. And a plurality of partition plate through holes that allow the plasma generation space and the film formation processing space to pass therethrough, and are separated from the plasma generation space. It has an internal space communicating with the film formation processing space through a plurality of diffusion holes, and the material gas is supplied to the internal space from the outside, and the material gas is introduced into the film formation processing space through the plurality of diffusion holes. In addition, the active species generated in the plasma generation space by applying high-frequency power to the high-frequency electrode to generate plasma discharge in the plasma generation space, through the plurality of partition plate through holes of the partition plate In a CVD apparatus that is introduced into a film formation processing space, and a film is formed on a substrate by the active species and the material gas introduced into the film formation processing space, a shield plate that can be separated from and contacted with the partition plate is formed. A CVD apparatus, which is arranged on the film processing space side. 2. The shield plate is provided with a convex portion at a position facing the plurality of partition plate through holes of the partition plate, the convex portion being fitted into a concave portion of the partition plate through hole on the side facing the shield plate. With
The partition plate is provided with holes at positions facing the plurality of diffusion holes, and the convex portion is provided with a shield plate through hole,
When the shielding plate is in close contact with the partition plate and the protrusion is fitted in the recess, the partition plate through hole and the shielding plate through hole allow the plasma generation space and the film formation processing space to communicate with each other. The CVD apparatus according to claim 1, characterized in that: 3. A method of performing a post-treatment process after film formation using the CVD apparatus according to claim 1 or 2, wherein the conductive partition plate is set to the ground potential while the plasma generation space is used for the post-treatment process. By introducing a gas and applying high-frequency power to the high-frequency electrode to generate plasma discharge, active species are generated in the plasma generation space, the shield plate is separated from the partition plate, and the shield plate is separated from the partition plate. While
A CVD apparatus characterized in that the generated active species is introduced into the film formation processing space from the plasma generation space through the plurality of partition plate through holes, and post-treatment after film formation is performed in the film formation processing space. A method of performing a post-treatment process after film formation.