JPH0685393B2 - Deposited film forming equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a deposited film forming apparatus for decomposing a raw material gas by utilizing an electric discharge phenomenon and depositing and forming a thin film on a surface of a substrate. Such a deposited film forming apparatus is a plasma CV for depositing and forming a thin film of, for example, amorphous silicon (a-Si).
Effectively applied to D devices.

[Conventional technology]

FIG. 3 is a schematic configuration diagram showing an example of a conventional plasma CVD apparatus having a coaxial electrode structure.

In FIG. 3, reference numeral 2 is a deposition chamber, 4 is a cathode electrode which is electrically insulated from the deposition chamber 2, and 6
Is an anode electrode arranged so as to be electrically insulated from the deposition chamber 2. The cathode electrode 4 is made to project upward in a cylindrical shape in the deposition chamber 2, while the anode electrode 6 has a hollow cylindrical portion having an inner diameter larger than the cylindrical outer diameter of the cylindrical cathode electrode 4. The hollow cylindrical portion is the cathode electrode 4
It is arranged so as to be coaxial with. A base holder (not shown) is fixed to the inner peripheral wall surface of the hollow cylindrical portion of the anode electrode 6, and the base 8 is fixed by the holder.
Is held. An exhaust system 10 for exhausting the deposition chamber 2 to a high vacuum is connected to the deposition chamber 2. Further, a source gas introduction system 12 and a power supply system 14 are connected to the cathode electrode 4. The anode electrode 6 is grounded.

FIG. 4 shows an example of the internal structure of the cathode electrode 4 of the conventional plasma CVD apparatus as described above.

In FIG. 4, 20 is a metal pipe which penetrates the bottom surface of the deposition chamber 2. The pipe is an insulating member
It is held on the bottom surface of the deposition chamber 2 via 22. The pipe
A metal plane plate 24 is fixed to the upper end of 20, and a cylindrical cathode electrode surface plate 26 having an axis of symmetry in the vertical direction is fixedly mounted on the plane plate. The top surface of the electrode surface plate is closed as shown in the drawing, and a large number of gas ejection holes 28 are formed on the circumferential surface. Inside the cylindrical surface of the electrode surface plate 26, a gas retention chamber 30 is formed all around,
32 is a metal partition wall for forming the retention chamber. On the other hand, 34 is a raw material gas passage made of metal, the passage passing through the pipe 20, penetrating the flat plate 24, extending upward, penetrating the partition wall 32 and the gas retention chamber 30. It is in communication.

The source gas introduction system 12 is in communication with the gas passage 34,
On the other hand, the above power supply system (for example, 13.56MHz high frequency power supply)
The gas passage 34 is connected to one terminal of 14 so that electric power can be supplied to the cathode electrode surface plate 26 through the passage 34 and the partition wall 32. The other terminal of the power supply system 14 is connected to the deposition chamber 2 and grounded.

In order to form a deposited film on the surface of the substrate 8 in the above plasma CVD apparatus, after the inside of the deposition chamber 2 is evacuated to a high vacuum by the exhaust system 10, the gas introduction system 12 causes the gas retention chamber 30 to pass through the gas passage 34. A raw material gas is introduced into the inside of the accumulating chamber, and the raw material gas is uniformly ejected into the deposition chamber 2 through the gas ejection holes 28 from the retention chamber to a predetermined gas pressure. Then, the cathode electrode surface plate 26 is fed by the power supply system 14 via the gas passage 34 and the partition wall 32.
A predetermined high frequency voltage is applied to. This induces a discharge between the cathode electrode surface plate 26 and the anode electrode 6,
The raw material gas is decomposed into plasma by this discharge energy, and at least a part thereof is deposited on the surface of the substrate 8 to form a deposited film.

[Problems to be solved by the invention]

However, in the conventional deposited film forming apparatus as described above, since the power supply system is connected to the cathode electrode surface plate 26 via the raw material gas passage 34 and the partition wall 32, power loss or the like, Further, an electric discharge is generated in the gas passage 34 and the gas retention chamber 30, and the raw material gas is decomposed before being ejected into the deposition chamber 2 and deposited on the wall surfaces of the gas passage 34 and the gas retention chamber 30. There was a problem.

[Means for solving problems]

According to the present invention, as a solution to the above-mentioned problems of the prior art, a source gas is decomposed by using a discharge phenomenon between two electrodes arranged in a deposition chamber and held in the deposition chamber. In a deposited film forming apparatus for forming a deposited film on the surface of a substrate, one of the two electrodes has a plurality of gas retention chambers for sequentially retaining the source gas introduced into the electrode, The electrode has a surface member provided with a gas ejection hole for ejecting a source gas into the deposition chamber, the surface member is connected to a power supply system, and the surface member supplies the source gas. The source gas introduction system for introducing into the electrode from the outside is electrically insulated from other than the surface member and from members forming the gas retention chamber other than the surface member. Together with the raw material A deposition film forming apparatus, characterized in that the introduction system other than the surface member and the members forming the gas retention chamber other than the surface member are both at ground potential. .

〔Example〕

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of an electrode portion showing a first embodiment of the device of the present invention. The present embodiment is applied to a plasma CVD apparatus having a coaxial type electrode structure, and FIG. 1 shows the same portion as FIG.

In FIG. 1, 2 is a deposition chamber, and a cathode electrode 4 is arranged on the bottom surface of the deposition chamber. Reference numeral 40 denotes a surface plate of the cathode electrode, which has a cylindrical shape similar to that shown in FIG. The electrode surface plate 40 is fixed on the bottom surface of the deposition chamber 2 via an insulating member 42. The electrode surface plate 40
A large number of gas ejection holes 44 are formed in the cylindrical surface of the. Inside the cathode electrode 4 are a plurality of source gas retention chambers 46, 48, 50.
Are formed. The gas retention chamber 46 is formed inside the electrode surface plate 40, the gas retention chamber 48 is formed inside the gas retention chamber 46, and the gas retention chamber 50 is the gas retention chamber.
Formed inside 48. Reference numeral 52 is a partition wall for forming these gas retention chambers, which is made of a conductive material. The partition
A large number of gas circulation holes 54 are provided in 52 for communicating between the gas retention chambers. Reference numeral 56 denotes a raw material gas passage made of a conductive material, which connects the external raw material gas source and the innermost gas retention chamber 50. As shown, the gas passage 56 is grounded.

In FIG. 1, reference numeral 58 is a power supply line, one end of which is connected to the cathode electrode surface plate 40. Reference numerals 60 and 62 denote insulating members, which hold the power supply line 58 on the partition wall 52 and the bottom surface of the deposition chamber 2 in an electrically insulated state. The other end of the power supply line 58 is connected to one terminal of the high frequency power supply 14, and the other terminal of the high frequency power supply is grounded.

In the apparatus of this embodiment, the high voltage of the high frequency power source 14 is in a state of being completely electrically insulated from the gas passage 56 for introducing the raw material gas and the partition wall 52 forming the gas retention chambers 46, 48, 50. It is supplied to the cathode plate 40. Therefore, the gas passage
No discharge occurs in 56 and in the gas retention chambers 48, 50. In this embodiment, the high frequency power source 14 is 1
Especially when 3.56MHz is used, the electrode surface plate 40 and the gas retention chamber 4
By setting the distance from the partition wall 52 forming 6 to 5 mm or less, preferably 2 mm or less, it is possible to prevent discharge from occurring in the gas retention chamber 46.

FIG. 2 is a sectional view of an electrode portion showing a second embodiment of the device of the present invention. This embodiment is applied to a plasma CVD apparatus having a parallel plate type electrode structure.

In FIG. 2, reference numeral 2 denotes a deposition chamber made of a conductive material, and the cathode electrode 4 is arranged on the bottom surface of the deposition chamber. Reference numeral 40 denotes a surface plate of the cathode electrode, which has the same cylindrical shape as the electrode surface plate 40 in FIG. However, the height of the electrode surface plate 40 in this embodiment is relatively low. 42 is an insulating member. A large number of gas ejection holes 44 are formed in the top plane of the electrode surface plate 40. Inside the cathode electrode 4, a plurality of source gas retention chambers 46, 48, 50 are formed. Reference numerals 52 and 53 are partition walls for forming these gas retention chambers and are made of a conductive material. A large number of gas flow holes 54 are formed in the top plane of these partition walls. Reference numeral 56 denotes a raw material gas passage, which connects an external raw material gas source and the innermost gas retention chamber 50. The gas passage is grounded. Reference numeral 58 is a power line, one end of which is connected to the cathode electrode surface plate 40. Reference numerals 60, 61 and 62 denote insulating members which hold the power supply line 58 in an electrically insulated state on the partition walls 52, 53 and the bottom surface of the deposition chamber 2. The power line
The other end of 58 is connected to one terminal of the high frequency power supply 14, and the other terminal of the high frequency power supply is grounded.

In the device of this embodiment, a flat plate-shaped anode electrode is arranged above the cathode electrode 4, and the anode electrode is grounded.

Also in the device of this embodiment, it is possible to prevent the occurrence of electric discharge in the gas passage 56 and the gas retention chambers 46, 48, 50 as in the first embodiment.

〔The invention's effect〕

As described above, according to the present invention, it is possible to prevent the occurrence of discharge in the route of introducing the raw material gas into the deposition chamber, thus preventing the film deposition in the route, and efficiently using the raw material gas and the efficiency of the power supply. Utilization is realized.

In addition, as a result that the power supply path is separated from the source gas introduction path, it is possible to prevent the power supply path to the cathode electrode surface plate from coming into contact with the source gas. It can be made of a material that is easily treated, and by using a metal having good conductivity such as copper as such a material, it is possible to improve the stability of power supply and the stability of discharge between electrodes.

Furthermore, in the present invention, the source gas can be sequentially passed through a plurality of spaces for gas retention in the electrode and ejected into the deposition chamber with good uniformity, so that a deposited film with good uniformity can be formed. You can

[Brief description of drawings]

1 and 2 are sectional views of the cathode electrode portion of the device of the present invention. FIG. 3 is a schematic configuration diagram of a plasma CVD apparatus. FIG. 4 is a sectional view of a cathode electrode portion in a conventional plasma CVD apparatus. 2: Deposition chamber, 4: Cathode electrode, 6: Anode electrode, 8: Substrate,
14: power supply system, 40: power supply surface plate, 42, 60, 61, 62: insulating member, 44: raw material gas ejection hole, 46, 48, 50: raw material gas retention chamber, 5
2, 53: partition wall, 54: raw material gas passage hole, 56: raw material gas passage, 58:
Power line.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masaki Fukaya 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) Reference JP-A-57-37821 (JP, A) JP-A-61 -87872 (JP, A) JP-A-61-37969 (JP, A) Actually developed 60-52619 (JP, U)

Claims (1)

[Claims] 1. A deposited film forming apparatus for decomposing a source gas by utilizing a discharge phenomenon between two electrodes arranged in a deposition chamber to form a deposited film on a surface of a substrate held in the deposition chamber. In one of the two electrodes, a plurality of gas retention chambers for sequentially retaining the source gas introduced into the electrodes are provided, and the electrodes are gas for ejecting the source gas into the deposition chamber. It has a surface member provided with ejection holes, the surface member is connected to a power supply system, and the surface member is a source gas introduction system for introducing the source gas into the electrode from the outside. Of the raw material gas introduction system, other than the surface member and electrically insulated from members other than the surface member among members forming the gas retention chamber, and other than the surface member And the gas retention Wherein the something other than the surface member of the members forming is the ground potential together, the deposited film forming apparatus.