JP3117366B2 - Plasma processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus used as a dry etching apparatus, a plasma chemical vapor deposition (hereinafter, referred to as plasma CVD) apparatus, an ashing apparatus, and the like.

[0002]

2. Description of the Related Art A conventional plasma CVD apparatus will be described with reference to FIG. In the apparatus shown in FIG. 5A, a processing substrate is installed between high-frequency electrodes installed in a vacuum vessel,
FIG. 5 shows a parallel plate type plasma processing apparatus for performing plasma processing on a substrate by plasma generated between electrodes.
The apparatus shown in FIG. 1B is an inductively coupled plasma processing apparatus that winds a discharge coil around a quartz discharge tube, generates plasma inside the discharge tube, and performs plasma processing on a substrate on a substrate holder.

The feature of the apparatus shown in FIG. 5A is that it is the most orthodox type because it can process a large area substrate of about 70 cm square. In the case of this device, the high-frequency power source 1
The high-frequency electrode 4 to which the first electrode 6 is connected and the substrate holder electrode 6 are arranged so as to be substantially parallel to each other, and a plasma discharge field 11 is formed between the two electrodes 4 and 6.
The substrate 1 to be heated is disposed, the other electrode 4 is provided with a porous shape to have air permeability, and a shield 3 is provided.

[0004] The reaction gas 2 introduced into the vacuum vessel 5 passes through the electrode 4 and is guided into the plasma discharge field 11.
The gas decomposed by plasma by passing through the plasma discharge field 11 is supplied to the processing surface of the substrate 1.

In the case of the inductive coupling type apparatus shown in FIG. 5B, a discharge coil 12 is arranged above a quartz discharge tube 13. The discharge coil 12 forms a plasma discharge field 11 'in a vacuum vessel 5' below the substrate. In the vacuum vessel 5 ', a substrate 1' having a film-forming surface facing the plasma discharge field 11 'and this substrate 1' And a heater 8 'provided on the back of 1'.

A reaction gas 2 'is introduced into the quartz discharge tube 13, and the reaction gas 2' is supplied to the plasma discharge field 11 '.
Through the substrate 1 'to the processing surface of the substrate 1'.

[0007]

SUMMARY OF THE INVENTION In a conventional device,
In the case of a parallel plate type plasma processing apparatus, it is possible to cope with an increase in size by increasing both electrodes, but the surface area of the electrodes becomes equal to or greater than the substrate surface area, so that the high-frequency power density per unit area decreases, When high-speed, large-area substrate processing is performed, decomposition of the reaction gas becomes insufficient, and there has been a problem that it is difficult to achieve good substrate processing.

In the case of an inductively coupled plasma processing apparatus, if the size of the vacuum vessel is increased along with the increase in the size of the substrate, the diameter of the discharge coil increases, making it difficult to perform uniform discharge. There has been a problem that some kinds of plasma CVD apparatuses can cope only with small substrates.

In order to solve the above-mentioned problems, the present invention provides a plasma processing apparatus capable of making the plasma distribution uniform on a large-sized substrate and easily performing good plasma processing on a large-area substrate. The purpose is to do.

[0010]

[Means for Solving the Problems]

(1) A plasma processing apparatus according to the present invention includes a vacuum vessel provided with a supply section and a discharge section for a reaction gas, a substrate holder provided in the vacuum vessel and having a substrate disposed on one surface thereof, A first electrode, which is a planar coil electrode that is disposed parallel to one surface and has a sparse element spacing, and is disposed in parallel between the first electrode and the substrate holder and has a dense element spacing. A second electrode, which is a planar coil electrode, and a high-frequency power source to which the first electrode and the second electrode are connected are provided.

(2) The present invention is characterized in that, in the plasma processing apparatus according to the above invention (1), the first electrode and the second electrode are respectively arranged so as to be able to freely contact and separate from the substrate.

[0012]

In the above invention (1), the reaction gas supplied from the supply section into the vacuum vessel is guided to the plasma discharge field formed by the first electrode and the second electrode and is decomposed to generate a reaction gas plasma. Then, plasma processing is performed on the processing surface of the substrate.

Since the first electrode and the second electrode are formed by planar coil electrodes, the surface area of the electrodes can be made smaller and the high-frequency power density can be increased as compared with a conventional parallel plate type electrode. Therefore, the ability to decompose the reaction gas can be increased.

In the case of the flat coil electrode, when the element spacing is sparse, there is a portion where the high-frequency power density is higher than in the case where the element spacing is high. Prone. On the other hand, when the density is high, the decomposition of the reaction gas does not proceed, but the homogenization is improved.

Therefore, in the present invention, the first electrode and the second electrode are arranged in parallel with respect to the substrate holder to enhance the ability to decompose the reaction gas and to make the reaction gas uniform, and to provide a good and uniform plasma. Processing can be achieved efficiently.

In the above invention (2), since the positions of the first electrode and the second electrode with respect to the substrate in the above invention (1) can be freely separated from each other, the substrate can be treated under optimum conditions by adjusting this. The surface can be subjected to plasma processing.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. The present embodiment shown in FIG.
The substrate holder 18 is provided at a lower portion of the vacuum chamber 4 and has a heater 15 disposed on a lower surface and a substrate 19 is mounted on an upper surface. The substrate holder 18 also serves as a heat equalizing plate. A gas supply pipe 23 to which a reaction gas 24 is supplied from the outside, and is disposed between the gas supply pipe 23 and the substrate holder 18 and has a shape shown in FIG. The first electrode 16 which is a planar coil electrode, the first electrode 16 and the substrate holder 1
8 and a vacuum pump connected to the bottom surface of the vacuum vessel 14, the second electrode being a planar coil electrode having the shape shown in FIG. 22. The first and second electrodes 16 and 17 are connected to high-frequency power supplies 20 and 21 provided outside the vacuum vessel 14, respectively.

In the above, the reaction gas 24 is supplied into the vacuum chamber 14 by the gas supply pipe 23, and the reaction gas 24 and the
Excess products generated during ashing are supplied to the vacuum pump 2
2 discharges to the outside of the vacuum container 14.

The first electrode 16 and the second electrode 17 are
High-frequency power is supplied from the high-frequency power supplies 20 and 21, respectively, to form a plasma discharge field, into which the reaction gas supplied by the gas supply pipe 23 is introduced, and the uniformly decomposed reaction gas plasma is generated. Generated
Good and uniform plasma processing is performed on the processing surface of the substrate 19.

In this embodiment, a flat coil electrode is used. The reason will be described below. In the case of a plasma processing apparatus using a parallel plate type electrode, which has been used relatively frequently for processing a large area substrate in the past, an electrode area equal to or larger than the substrate is required, the high-frequency power density per unit area is low, and the reaction gas In order to supply high-frequency power until a high-frequency power density capable of sufficiently decomposing is obtained, the electrode cooling system and the power introduction unit become very large, and the efficiency is low.

On the other hand, in the case of the plasma processing apparatus using the planar coil electrode shown in FIG. 1B as the high-frequency electrode in this embodiment, the electrode surface area is small with respect to the supplied high-frequency power. Thus, a high-frequency power density can be obtained, and the reaction gas can be sufficiently decomposed.

In this embodiment, the first electrode 16 and the second electrode 17, which are flat coil electrodes having a sparse and dense pole pitch, are used. The reason will be described below. When the planar coil electrode shown in FIG. 1B is used, the high-frequency power density is such that a concentric electric field is formed around the pole near the electrode, as shown in FIG. 2 near the electrode. The distribution becomes uneven.

When the same high-frequency power is input to the planar coil electrode shown in FIG. 1B, the smaller the number of poles, the higher the high-frequency power density and the reaction gas is easily decomposed.
As shown in FIG. 2A, the distribution of the high-frequency power density becomes non-uniform. On the other hand, when the number of pole bars is increased, the uniformity is improved as shown in FIG. 2B, but the high-frequency power density is reduced and the decomposition of the reaction gas does not progress relatively.

Therefore, in this embodiment, in order to improve the respective disadvantages, the first electrode 1 having a small number of poles is used.
6, the electrode having a large number of poles is employed as the second electrode 17, so that the first electrode 16 promotes highly efficient decomposition of the reaction gas, and the second electrode can achieve uniformity.

The first electrode 16 and the second electrode 1
The distance 7 from the substrate 19 is adjustable, so that the decomposition and uniformization of the reaction gas can be optimized.

In this embodiment, the case where different high-frequency power sources are connected to the first electrode and the second electrode has been described.
As shown in FIG. 3, the first electrode and the second electrode may be integrated, and a single high-frequency power supply may be connected thereto.

In this embodiment, the case where the ladder-type flat coil type electrode is used has been described. However, the present invention is not limited to this, as long as the electrode has an inductance. Electrodes can be used.

[0028]

According to the plasma processing apparatus of the present invention, a substrate holder on which a substrate is provided is provided in a vacuum vessel provided with a supply portion and a discharge portion for a reaction gas, and the substrate of the substrate holder is provided. By arranging the first electrode and the second electrode, which are flat coil electrodes having sparse and dense element intervals in parallel to the surface, the first electrode having a high high frequency power density near the electrodes is capable of decomposing the reaction gas. And the second electrode having a uniform high-frequency power density in the vicinity of the electrode makes it uniform, so that good and uniform plasma processing can be achieved. Further, since the arrangement positions of the first electrode and the second electrode can be adjusted, plasma processing under optimum conditions can be performed.

[Brief description of the drawings]

1A and 1B are explanatory diagrams of a plasma processing apparatus according to an embodiment of the present invention, wherein FIG. 1A is an overall explanatory diagram, and FIG. 1B is an explanatory diagram of a planar coil electrode.

FIGS. 2A and 2B are explanatory diagrams of the operation of the planar coil electrode according to the embodiment, wherein FIG. 2A is a diagram illustrating a case where the pole bar pitch is sparse, and FIG.

FIG. 3 is an explanatory diagram of a case where first and second electrodes according to the one embodiment are integrated.

FIG. 4 is an explanatory diagram of another shape of the first and second electrodes according to the embodiment.

FIG. 5 is an explanatory diagram of a conventional device.

[Explanation of symbols]

 14 vacuum vessel 15 heater 16 first electrode 17 second electrode 18 substrate holder 19 substrate 20, 21 high frequency power supply 22 vacuum pump 23 gas supply pipe 24 reaction gas

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Takeshi Hamamoto 1-1, Akunouramachi, Nagasaki-shi, Nagasaki Shipyard, Mitsubishi Heavy Industries, Ltd. (58) Field surveyed (Int. Cl. ⁷ , DB name) H05H 1 / 46 C23C 16/50 C23F 4/00 H01L 21/3065

Claims (2)

(57) [Claims] 1. A vacuum vessel provided with a supply part and a discharge part of a reaction gas, a substrate holder provided in the vacuum vessel and having a substrate disposed on one surface thereof, and a substrate facing one surface of the substrate holder. The first electrode is a planar coil electrode which is disposed in parallel and has a sparse element spacing, and is a planar coil electrode which is disposed in parallel between the first electrode and the substrate holder and has a dense element spacing. A plasma processing apparatus comprising: a second electrode; and a high-frequency power source connected to the first electrode and the second electrode. 2. The plasma processing apparatus according to claim 1, wherein the first electrode and the second electrode are respectively disposed so as to be able to freely contact and separate from the substrate.