JPH0729890A - Plasma producing equipment - Google Patents

Abstract

PURPOSE:To provide an efficient plasma producing equipment of a simple structure that calls for less fabricating cost and maintenance cost and produces plasma with uniform density and less diffusion. CONSTITUTION:A plasma diffusion shielding wall 31 is placed around a space where plasma is to be produced in a plasma producing equipment including a coil 26 for producing plasma. Thus plasma is contained and produced within the space enclosed with the wall. This prevents the diffusion of plasma and improves the efficiency of producing plasma.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma generator such as a semiconductor manufacturing apparatus for processing an object to be processed such as a wafer or a glass substrate using plasma.

[0002]

2. Description of the Related Art A conventional plasma generator will be described with reference to FIG.

A processing table 3 is installed below a reaction chamber 2 defined by a vacuum container 1, and an object 4 to be processed such as a wafer or a glass substrate is placed thereon. A plate electrode 5 is provided above the reaction chamber 2, and the plate electrode 5 is insulated from the vacuum container 1 by an insulating block 6. A high frequency power source 7 is connected to the plate electrode 5 via a matching unit 10.

The reaction chamber 2 is evacuated by a vacuum pump 8, gas is introduced into the reaction chamber 2 in a depressurized state through a gas introducing pipe 9, and the pressure is set by a pressure control device (not shown). The high frequency power to be output is supplied through the matching device 10 to generate the plasma 11 in the reaction chamber 2. The object to be processed 4 on the processing table 3 is processed by the plasma 11.

This plasma generator is used for plasma etching and plasma CVD (Chemical Vapor).
It is used for devices such as Deposition).

Next, another conventional plasma generator will be described with reference to FIG. FIG. 4 shows a plasma processing apparatus, especially ECR (Electron Cyclotron R).
Figure 3 shows an etching device. Figure 4
Among them, those having the same functions as those shown in FIG. 3 are denoted by the same reference numerals.

A buffer container 13 defining a buffer chamber 12 is connected to the lower end of the vacuum container 1, and a plate electrode 5 is provided below the reaction chamber 2. The object 4 to be processed is placed on the plate electrode 5. A cooler 18 is provided in the vacuum container 1, and water is supplied from a water supply port 19, and the cooler 18 is circulated and drained from a drain port 20 to cool the vacuum container 1. The upper end of the vacuum container 1 is partitioned by a quartz plate 15, a waveguide 14 having a hollow rectangular cross section is connected to the upper end of the vacuum container 1, and the microwave output from a microwave power source 16 is passed through the quartz plate 15 to form the microwave. The structure leads to the reaction chamber 2. A magnetic field generating coil 17 for generating a magnetic field in the reaction chamber 2 is installed around the reaction chamber 2. Reaction chamber 2
The output of the high frequency power source 7 can be supplied to the flat plate electrode 5 installed at the lower part of the through a matching unit 10.

The flat plate electrode 5 penetrates the bottom surface of the buffer container 13, and the penetrating portion is insulated from the buffer container 13 by an insulating block 6. A correction coil 21 for correcting the distribution of the magnetic field generated by the magnetic field generation coil 17 is provided inside the buffer container 13.

The reaction chamber 2 and the buffer chamber 12 are vacuum pumps 8
The gas is introduced from the gas introduction pipe 9 into the reaction chamber 2 under reduced pressure, the pressure is set by a pressure control device (not shown), and the microwave output from the microwave source is supplied to the reaction chamber by the rectangular waveguide 14. Introduced in 2. In the reaction chamber 2, high density plasma 11 is generated by utilizing electron cyclotron resonance (ECR) by the microwave and the magnetic field generated by the magnetic field generating coil 17.

At the same time, high frequency power is applied to the flat plate electrode 5 from a high frequency power source 7 to generate a DC bias voltage on the flat plate electrode 5 to move a large amount of ions in the plasma to the side of the object 4 to be processed on the flat plate electrode. , The workpiece 4 placed on the plate electrode 5
To etch. Other devices that utilize electron cyclotron resonance include plasma CVD devices.

[0011]

In the above-mentioned conventional plasma generator, since the plate electrode 5 for generating plasma is provided inside the reaction chamber 2, the number of parts in the reaction chamber increases. The structure becomes complicated. If the structure of the reaction chamber becomes complicated, the number of locations contaminated by the reaction products increases, and it becomes difficult to remove the contamination.

Contamination by the reaction product on the electrode surface may change the conductive area of the electrode, which may change the plasma state, which may hinder the processing of the object to be processed. Therefore, it is necessary to frequently clean the inside of the reaction chamber, which causes problems such as an increase in maintenance cost and a decrease in operating rate.

Further, in the latter case of generating plasma by utilizing electron cyclotron resonance, a microwave source 16 and a waveguide 14 for introducing microwave into the reaction chamber 2 in order to satisfy the condition of this electron cyclotron resonance. The magnetic field generating coil 17 for generating a magnetic field in the reaction chamber, the water cooling mechanism for cooling the coil, and the like are required, which complicates the apparatus, increases the size of the apparatus, and increases the cost.

Further, it is difficult to make the strength of the magnetic field generated by the coil uniform in the upper part of the object to be processed, so that the plasma becomes nonuniform and problems such as etching occur. Since this tendency becomes more remarkable as the size of the object to be processed becomes larger, there is a problem that it is difficult to process a large object to be processed.

In view of such circumstances, the present invention aims to provide an efficient plasma generator having a simple structure, low manufacturing cost, low maintenance cost, uniform plasma density, and small plasma diffusion. Is.

[0016]

SUMMARY OF THE INVENTION The present invention is a plasma generator having a plasma generating coil, characterized in that a plasma diffusion shield wall surrounding a plasma generating space is provided.

[0017]

Since the plasma is enclosed and generated in the space surrounded by the plasma diffusion shield wall, the diffusion of the plasma is prevented and the plasma generation efficiency is improved.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

A ceiling plate 22 made of an insulating material such as quartz is detachably mounted on the upper surface of a rectangular vacuum container 23 to form a reaction chamber 24 having a vacuum airtight structure, and a vacuum pump 30 is connected to the reaction chamber 24. At the same time, the gas introduction pipe 29 penetrating the ceiling plate 22 is connected.

Inside the reaction chamber 24, the object mounting table 2 is placed.
5 is provided so that the object 4 to be processed is placed on the object placing table 25. A plasma diffusion shield wall 31 is provided on the ceiling plate 22. The plasma diffusion shield wall 31 includes a flange 31a having the same outer shape as the ceiling plate 22 and a cylindrical body 31b depending from the flange 31a. The flange 31a is attached to the rectangular vacuum container 23 integrally with the ceiling plate 22. The cylindrical body 31b substantially surrounds the space where the ceiling plate 22 and the object mounting base 25 face each other. The gas introduction pipe 29 is open to a space 33 surrounded by the cylindrical body 31b.

As shown in FIG. 2, the plasma diffusion shield wall 31 is provided with a notch 32 whose lower end is notched over a substantially semicircle. The workpiece 4 is carried in and out of the workpiece mounting table 25 through the cutout portion 32. The material of the plasma diffusion shield wall 31 is a conductive material such as aluminum, and the surface thereof is coated with an insulating material such as alumina in order to prevent reaction of the surface.

A plasma generating coil 26 is provided on the upper surface of the ceiling plate 22. The plasma generating coil 26 has a flat coil winding shape, the plasma generating coil 26 is grounded via the vacuum container 23, and the plasma generating coil 26 is supplied with a high frequency wave via a matching unit 27. Power supply 2
8 are connected.

The reaction chamber 24 is evacuated by the vacuum pump 8 to a depressurized state, and the reaction gas is introduced into the space 33 of the depressurized reaction chamber 24 through the gas introduction pipe 29, so that the inside of the reaction chamber 24 is reduced. Is maintained at a pressure set by a pressure control device (not shown).

When the high frequency power output from the high frequency power supply 28 is applied to the plasma generating coil 26 through the matching unit 27, the electromagnetic waves emitted from the plasma generating coil 26 surround the plasma diffusion shield wall 31 of the reaction chamber 24. Plasma 11 is generated in the open space 33. The plasma diffusion shield wall 31 encloses the plasma 11 inside the plasma diffusion shield wall 31 and prevents the diffusion of the plasma 11.

By the plasma 11, the object 4 to be processed on the object mounting table 25 is processed.

The plasma diffusion shield wall 31 may be a punching metal or a mesh plate.

As the object to be treated 4 is treated, reaction products adhere to the inner wall of the reaction chamber and the plasma diffusion shield wall 31, so it is necessary to clean it regularly or according to the operating condition. As described above, since the plasma diffusion shield wall 31 is provided with the ceiling plate 22, it can be removed integrally with the ceiling plate 22 when the ceiling plate 22 is removed, and maintenance is easy.

[0028]

As described above, according to the present invention, plasma can be generated only in a required space, plasma diffusion can be prevented, and plasma generation efficiency can be remarkably improved. Further, the workability of maintenance such as cleaning can be improved.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the present invention.

FIG. 2 is a perspective view of a plasma diffusion shield wall in the present embodiment.

FIG. 3 is a schematic cross-sectional view showing a conventional example.

FIG. 4 is a schematic sectional view showing another conventional example.

[Explanation of symbols]

 4 Processing Object 11 Plasma 22 Ceiling Plate 23 Rectangular Vacuum Container 25 Processing Object Placement Table 26 Plasma Generating Coil 31 Plasma Diffusion Shielding Wall 32 Notch 33 Space

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H05H 1/46 9014-2G

Claims (5)

[Claims] 1. A plasma generator having a plasma generating coil, wherein a plasma diffusion shield wall surrounding a plasma generation space is provided. 2. The plasma generator according to claim 1, wherein the material of the plasma diffusion shield wall is a conductive material, and the surface of the plasma diffusion shield wall is coated with an insulator. 3. The plasma generator according to claim 1, wherein the plasma diffusion shield wall is a punching metal. 4. The plasma generator according to claim 1, wherein the plasma diffusion shield wall is a mesh plate. 5. A vacuum chamber having an open upper part is closed by a ceiling plate to form a reaction chamber having a vacuum airtight structure, a plasma diffusion shield wall is provided on the ceiling plate side, and the plasma diffusion shield wall can be removed together with the ceiling plate. The plasma generator according to claim 1.