JP3079838B2 - Plasma CVD method and plasma CVD apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a plasma CVD method and a plasma CVD apparatus for forming a thin film on a long substrate such as a plastic film.

[0002]

2. Description of the Related Art Plasma CVD is a method in which a glow discharge is generated by a high-frequency electric field in a reaction gas in a vacuum chamber, the gas is activated using the electric energy, and the gas is decomposed by a plasma reaction to decompose the substrate. In this method, a semiconductor thin film, a silicon nitride thin film, a silicon oxide thin film, or the like is formed by forming a thin film thereon. In order to form a film on a flexible long substrate such as a plastic film, a substrate wound from one roll to the other roll is passed through a film forming chamber equipped with a pair of plate electrodes facing each other in parallel, A reaction gas is introduced into a vacuum chamber, and a voltage is applied between the electrodes to generate a plasma C.
VD is performed. At this time, there are a roll-to-roll system in which the substrate is moved and a step-roll system in which the substrate is stopped. Since a film is usually formed on only one surface of the substrate, the substrate is passed close to one electrode so that one surface faces the discharge space. Further, for example, in order to form a semiconductor thin film having a pin structure, it is necessary to pass a substrate through a plurality of film forming chambers into which different reaction gases are introduced.

[0003]

When a film is formed by the above-described method, when a discharge is generated between a high voltage electrode facing one ground electrode of the parallel plate electrode and a wall of a film forming chamber behind, grounding is performed. Electric power for generating a discharge between the electrode and the electrode becomes small, and there is a possibility that the discharge at the end of the electrode becomes non-uniform. Further, a product decomposed by the discharge may adhere to the wall surface of the film forming chamber and fall as a powder on the thin film surface on the substrate, thereby deteriorating the film quality. In order to prevent such discharge behind the electrode, it is necessary to increase the volume of the film forming chamber, and there is a problem that the apparatus cannot be made compact. On the other hand, when forming a film on a long substrate through a plurality of film forming chambers, it is necessary to provide a gate between the film forming chambers and pass the substrate.
In the case of the roll-to-roll system, a buffer vacuum chamber needs to be provided between the film forming chambers in order to prevent mixing of gases, so that there is a problem that the apparatus becomes complicated.

[0004] It is an object of the present invention to provide a plasma CVD method and a plasma CVD apparatus having no discharge behind a high voltage electrode, and further to provide a plasma CVD apparatus having a plurality of film forming chambers but having a simple structure. It is in.

[0005]

According to the present invention, a high-frequency voltage is applied to one of two plate electrodes opposed to each other in parallel, the other is grounded, and the other is grounded. In the plasma CVD method in which plasma is generated in the reaction space and the reaction gas is decomposed to deposit a thin film on the substrate, at least the reaction space is surrounded by close contact between the parallel plate electrode, the side wall, and the sealing material, and the substrate penetrates. A closed space is formed, and the reaction-reaction space side of the high-frequency electrode is 1 × 10 ^-3 To
It is to be brought into contact with a vacuum of rr or less. Further, according to the present invention, a high-frequency voltage is applied to one of the two flat electrodes facing each other in parallel, the other is grounded, plasma is generated in a reaction chamber between the two electrodes, and the reaction gas is decomposed. In a plasma CVD method for depositing a thin film on a substrate, there is provided a plurality of film-forming chambers through which a substrate, which at least surrounds a reaction space by close contact between a parallel plate electrode and a side wall and a sealing material, penetrates, and among the parallel plate electrodes, a ground electrode Are formed integrally in each film forming chamber, and the reaction-reaction space side of the high-frequency electrode is brought into contact with the atmosphere. Further, according to the present invention, a film forming chamber which is formed in close contact with at least two plate electrodes facing each other, a side wall, and a sealing material, and is connected to a gas introduction pipe and a gas exhaust pipe is installed in a vacuum chamber. A feeding mechanism and a winding mechanism for a flexible substrate that penetrate the film chamber in close proximity to one electrode are also plasma CVD apparatuses that are present in the vacuum chamber, and cover the surface of the high-frequency electrode exposed to the space inside the vacuum chamber. In this case, a shielding material having a ground potential is provided inside the vacuum chamber. Further, according to the present invention, a film forming chamber which is formed in close contact with at least two plate electrodes facing each other, a side wall, and a sealing material, and is connected to a gas introduction pipe and a gas exhaust pipe is installed in a vacuum chamber. A feeding mechanism and a winding mechanism for a flexible substrate that penetrates the film chamber in close proximity to one electrode are also a plasma CVD apparatus in the vacuum chamber, and the entire side wall of the film forming chamber is an insulator. I do. Further, according to the present invention, a film forming chamber which is formed in close contact with at least two plate electrodes facing each other, a side wall, and a sealing material, and is connected to a gas introduction pipe and a gas exhaust pipe is installed in a vacuum chamber. A flexible substrate feeding mechanism and a winding mechanism that penetrate the film chamber close to one of the electrodes are also provided with a plasma CV existing in the vacuum chamber.
In the D apparatus, a plurality of film forming chambers are provided, and each of the two film forming chambers is adjacent to each other with a common flat side wall having no space therein. Further, according to the present invention, a film forming chamber formed in close contact with at least two plate electrodes facing each other, a side wall, and a sealing material, and connected to a gas introduction pipe and a gas exhaust pipe is installed in a vacuum chamber. A flexible substrate feeding mechanism and a winding mechanism that penetrate the film chamber close to one of the electrodes are also provided with a plasma CV existing in the vacuum chamber.
In the D apparatus, a plurality of film forming chambers are provided, and each of the two film forming chambers is adjacent to each other with a common side wall provided with a communication hole communicating with the vacuum space. Further, according to the present invention, a plurality of film forming chambers which are formed in close contact with at least two plate electrodes facing each other, a side wall, and a sealing material, and are connected to a gas introduction pipe and a gas exhaust pipe are installed in a vacuum chamber, A feeding mechanism and a winding mechanism for a flexible substrate that penetrates the film forming chamber in the vicinity of one electrode are also plasma CVD apparatuses in which the vacuum chamber is present. It is assumed that they are integrally formed in a film forming chamber. Here, the outer surface of the high-frequency electrode of the two plate electrodes is preferably exposed to the atmosphere, and it is more preferable that a ground potential shielding material is provided to cover the surface of the high-frequency electrode exposed to the air. . Further, it is preferable that the side wall of the film formation chamber is electrically conductive and grounded while being insulated from the high-frequency electrode, or the entire side wall of the film formation chamber is made of an insulator. Further, it is preferable that two film forming chambers are adjacent to each other with a common side wall.

[0006]

[Action] The atmosphere in contact with the high-frequency electrode is 10 ^-1 Torr or less.
Discharge can occur if it is between 20 Torr, but 1 × 10 ^-3 Torr
No discharge occurs if the high-frequency electrode is in contact with the following vacuum or atmosphere. Therefore, a film forming chamber formed of parallel plate electrodes and side walls in a vacuum chamber of 1 × 10 ⁻³ Torr or less is used as a reaction space, or only the outer surface of the high-frequency electrode is exposed to the atmosphere, and If the gas introduction pipe and the gas exhaust pipe are connected, the reaction gas can be supplied only to the film forming chamber, and the discharge can be sealed therein. If the mechanism for feeding and winding the flexible substrate through the film forming chamber is also provided in a vacuum chamber surrounding the film forming chamber, the substrate surface and the formed film surface are prevented from being stained. When a plurality of stages of film formation are performed, a plurality of film formation chambers are provided in one vacuum chamber, and these film formation chambers are adjacent to each other with a common side wall, whereby a compact and simple plasma CVD apparatus can be obtained.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention will be described below with reference to the drawings in which common parts are denoted by the same reference numerals. In the embodiment shown in FIG. 1, three rectangular film forming chambers each having a side of 10 cm to 2 m are placed in a vacuum chamber 1 which can be evacuated from an evacuation pipe 42.
In each of the film forming chambers, a ground electrode 3 having a built-in heater and a hollow high-frequency electrode 4 to which a gas introduction pipe 41 is connected are opposed to each other at an interval of about 3 cm. . On the surface of the high-frequency electrode 4 facing the ground electrode 3, a hole 40 for gas release is formed. Each of the film forming chambers 21, 22, and 23 includes parallel plate electrodes 3, 4 and a grounded conductive side wall 6 made of metal, for example, stainless steel or aluminum, insulated from the high-frequency electrode 4 by an insulator 51. It has an enclosed internal space as a reaction space. A gas exhaust pipe 43 is opened in each conductive side wall 6. The plastic film 7, which is a flexible substrate, is stretched between the feed roller 71 and the take-up roller 72, and passes through each of the film forming chambers 21, 22, and 23 close to the ground electrode 3. Is pressed against the ground electrode via a vacuum sealing material 52 using an O-ring on the conductive side wall 6, and the airtightness of the film forming chamber is maintained. The airtightness of the film formation chamber is maintained at
Kept by 51.

[0008] To operate this plasma CVD apparatus,
The interior of the vacuum chamber 1 is reduced to 1 × 10
^-3 Torr or less, a different reaction gas or the same reaction gas is introduced into each film forming chamber, and a different pressure from the inside of the vacuum chamber 1 using a pressure display device and a pressure control system (not shown). Control to pressure state. Therefore, each of the film forming chambers 21 and 2
The airtightness of 2, 23 is different from the airtightness of a vacuum chamber surrounded by atmospheric pressure, and it is sufficient that even the pressure in the reaction space can be maintained. After a voltage is applied between the electrodes 3 and 4 to form a film on the stationary substrate 1, the ground electrode 3 is moved in the direction A and separated from the substrate 1. As a result, the pressure applied to the substrate 1 is eliminated, so that the substrate 1 is separated from the vacuum sealing material 52. In this state, the substrate 1 is wound up on the winding roll 72 by a predetermined length, the ground electrode is moved in the direction B to reproduce the sealing state, and the film is formed in the next step.
Note that the substrate 1 may be floated by moving the high-frequency electrode 4 and the side wall 6 without moving the ground electrode 3.

According to this embodiment, no discharge occurs because the space between the back surface of the high-frequency electrode 4 and the wall surface of the vacuum chamber 1 is a high vacuum of 10 ^-3 Torr or less. Further, since the transport system of the flexible substrate 7 such as the delivery roll 71 and the take-up roll 72 is outside the reaction space, it is possible to prevent contamination by electric discharge or fine powder generated in the film formation chamber. It becomes possible. According to the present embodiment, the volume inside the reaction space where the discharge occurs is small, and the gas flows efficiently,
It is possible to prevent the gas from generating staying fine powder inside the film formation chamber. At the same time, since the gas can be used efficiently, the gas yield can be improved and the film quality can be expected to be improved. If a replaceable deposition plate is provided on the inner surface of the conductive side wall 6 of the film forming chamber, a film can be prevented from being formed on the side wall 6. In the embodiment shown in FIG. 2, the portion of the high-frequency electrode 4 facing the wall surface of the vacuum chamber 1 is covered with a shield material 8 at an installation potential in a non-contact manner, and the plasma state of another film forming chamber is induced by high-frequency mutual induction. Is prevented from fluctuating.

In the embodiment shown in FIG. 3, the ground electrode 3 is common to each of the film forming chambers 21, 22, and 23 for forming a film by the step roll method, and each film forming chamber sandwiches the ground conductive side wall 6. Are adjacent. The high-frequency electrode 4 and the side wall 6 are insulated by an insulator 51. Further, the pressure in the vacuum chamber 1 is surely set to 10 ⁻³ Torr.
A communication hole 44 is formed in the side wall 6 outside the film forming chamber in order to keep the following. According to the present embodiment, since each of the film forming chambers 21, 22, and 23 is adjacent to each other with a side wall having a thickness of 5 to 20 mm, the ratio of the size of the vacuum chamber 1 to the size of the film forming chamber can be small.
The device becomes compact. It is to be noted that the side wall 6 has a two-layer structure, the vacuum sealing by the sealing material 52 with the substrate 7 is also performed at two places, and the intermediate space is connected to the internal space of the vacuum chamber 1
This is effective for preventing the reaction gas in the adjacent film forming chamber from being mixed.

In the embodiment shown in FIG. 4, a structure similar to that of FIG. 2 is provided on both sides of the ground electrode 3, and has approximately twice the mass productivity. This figure is a cross-sectional view as viewed from above, and the surface of the substrate 1 is in a vertical plane, and the adhesion of the fine powder dropped from the ceiling of the film forming chambers 21, 22, and 23 to the substrate surface is prevented. In other embodiments, it is also effective that the substrate surface is in the vertical plane.

In the embodiment shown in FIG. 5, each of the film forming chambers 21, 22,
The outer surface of the 23 high-frequency electrodes 4 is exposed to the atmosphere, and forms one wall surface of the vacuum chamber 1. Thereby, the size of the vacuum chamber 1 can be reduced. Under atmospheric pressure, no discharge occurs due to a voltage applied to a region used for this apparatus, and discharge occurs only in the film formation chamber. The surface of the high-frequency electrode 4 that is in contact with the atmosphere is provided with a ground potential shielding material 8 that is not in contact with the high-frequency electrode 4 or is connected via an insulator to prevent emission of electromagnetic waves. On the other hand, each of the film forming chambers 21, 22,
An insulator 51 covers the wall surfaces of the 23 ground conductive side walls 6.
By extending the high-frequency electrode 4 on the insulator 51 or detachably providing a floating potential preventing plate, the work of removing the film from the wall surface is facilitated. Also,
This insulator 51 also serves as a connected body of the high-frequency electrodes 4 of the film forming chambers 21, 22, and 23.

In each of the above embodiments, each of the film forming chambers 21, 22, 23
Are formed of metal and grounded, but the entire side wall may be replaced with an insulator. Although the substrate 7 is passed close to the ground electrode 3, the substrate 7 may pass close to the high-frequency electrode 4.

[0014]

According to the present invention, the back surface of the high-frequency electrode is
By contacting with a vacuum or atmospheric pressure of ^-3 Torr or less, discharge at the back of the high-frequency electrode was prevented, uniformity of discharge was obtained, and the film quality was improved. In addition, if a plurality of film forming chambers containing discharges are placed in one vacuum chamber, the film is sent out in the vacuum chamber, and films are sequentially formed on a flexible substrate to be wound up, a buffer vacuum is formed like a roll-to-roll type apparatus. There is no need to provide a chamber, so that the entire apparatus can be made compact and lightweight, and the manufacturing cost can be greatly reduced.

[Brief description of the drawings]

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

FIG. 2 is a sectional view of a plasma CVD apparatus according to another embodiment of the present invention.

FIG. 3 is a sectional view of a plasma CVD apparatus according to another embodiment of the present invention.

FIG. 4 is a sectional view of a plasma CVD apparatus according to another embodiment of the present invention.

FIG. 5 is a sectional view of a plasma CVD apparatus according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum chamber 21,22,23 Film-forming chamber 3 Ground electrode 4 High frequency electrode 41 Gas introduction pipe 42 Vacuum exhaust pipe 43 Gas exhaust pipe 51 Insulator 52 Vacuum sealing material 6 Conductive side wall 7 Plastic film 71 Sending roll 72 Take-up roll 8 Shielding material

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-291349 (JP, A) JP-A-59-99778 (JP, A) JP-A-63-282274 (JP, A) JP-A-60-1985 12735 (JP, A) JP-A-60-30124 (JP, A) JP-A-57-122581 (JP, A) JP-A-4-9474 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/205 H01L 31/04

Claims (12)

(57) [Claims] 1. A high-frequency voltage is applied to one of two plate electrodes opposed to each other in parallel, and the other is grounded to generate plasma in a reaction space between the two electrodes. in the plasma CVD method for depositing a thin film, a reaction space enclosed by the contact between the at least parallel plate electrode and the side wall and the sealing material, to form a closed space in which the substrate passes, the counter-reaction space side of the high-frequency electrode 1 × 10 ^-3 Plasma CVD characterized by contacting with a vacuum of Torr or less
Law. 2. A high-frequency voltage is applied to one of two plate electrodes opposed to each other in parallel, and the other is grounded to generate plasma in a reaction chamber between the two electrodes to decompose a reaction gas to form a reaction gas on a substrate. In a plasma CVD method for depositing a thin film on a substrate, a plurality of film forming chambers through which a reaction space penetrates at least a parallel plate electrode and a substrate surrounded by close contact between a side wall and a sealing material are provided, and a ground electrode of the parallel plate electrode is formed by each component. A plasma CVD method characterized by being integrally formed integrally with a film chamber, and bringing a reaction-reaction space side of a high-frequency electrode into contact with the atmosphere. 3. A film forming chamber, which is formed in close contact with at least two plate electrodes facing each other, a side wall, and a sealing material, and is connected to a gas introduction pipe and a gas exhaust pipe, is installed in a vacuum chamber. A feed-out mechanism and a take-up mechanism for a flexible substrate penetrating in proximity to one of the electrodes are also a plasma CVD apparatus present in the vacuum chamber, and cover a surface of the high-frequency electrode exposed to the space inside the vacuum chamber to ground potential. A plasma CVD apparatus, comprising: a shielding material provided in a vacuum chamber. 4. A film forming chamber, which is formed in close contact with at least two plate electrodes facing each other, a side wall, and a sealing material, and is connected to a gas introduction pipe and a gas exhaust pipe, is installed in a vacuum chamber. A plasma CVD apparatus in which a flexible substrate sending-out mechanism and a winding-up mechanism that penetrate in proximity to one electrode are also present in the vacuum chamber, wherein the entire side wall of the film forming chamber is made of an insulator. Plasma CVD equipment. 5. A film forming chamber which is formed in close contact with at least two plate electrodes facing each other, a side wall and a sealing material, and is connected to a gas introduction pipe and a gas exhaust pipe is installed in a vacuum chamber. A feeding and winding mechanism for a flexible substrate penetrating in proximity to one of the electrodes is also a plasma CVD apparatus in which the vacuum chamber is provided, and a plurality of film forming chambers are provided. A plasma CVD apparatus characterized in that a flat side wall having no space is commonly used and adjacent to each other. 6. A film forming chamber, which is formed in close contact with at least two plate electrodes opposed to each other, a side wall and a sealing material, and is connected to a gas introduction pipe and a gas exhaust pipe, is installed in a vacuum chamber. A feeding mechanism and a winding mechanism for a flexible substrate that penetrates in the vicinity of one electrode are also a plasma CVD apparatus in which the vacuum chamber is provided. A plasma CVD apparatus characterized in that it is adjacent to a common side wall provided with a communication hole communicating a space. 7. A plurality of film forming chambers, which are formed in close contact with at least two plate electrodes facing each other, a side wall, and a sealing material, and are connected to a gas introduction pipe and a gas exhaust pipe, are installed in a vacuum chamber. A flexible substrate sending-out mechanism and a winding-up mechanism that penetrate the chamber in close proximity to one of the electrodes are also a plasma CVD apparatus in which the vacuum chamber is provided. A plasma CVD apparatus, wherein the plasma CVD apparatus is integrally formed in common. 8. The plasma CVD apparatus according to claim 7, wherein the outer surface of the high-frequency electrode of the two plate electrodes is exposed to the atmosphere. 9. The plasma CVD apparatus according to claim 8, further comprising a ground potential shielding material covering a surface of the high-frequency electrode exposed to the atmosphere. 10. The plasma CVD apparatus according to claim 7, wherein a side wall of the film forming chamber is conductive, and is insulated from the high-frequency electrode and grounded. 11. The plasma CVD apparatus according to claim 7, wherein the entire side wall of the film forming chamber is made of an insulator. 12. The plasma C according to claim 7, wherein the two film forming chambers are adjacent to each other with a common side wall.
VD device.