JPH01181425A - Plasma processing device - Google Patents

Abstract

PURPOSE:To contrive miniaturization of the title plasma processing device by a method wherein a single magnetic coil wound along the expanded part of a waveguide is used as a magnetic coil. CONSTITUTION:As a single magnetic coil 1 is wound around along the expanded part of a waveguide tube, the coefficient of space utilization can be improved. As the number of turns of the coil can be reduced, which is necessary to obtain the density of magnetic flux required for plasma treatment, at the top part 3a where the maximum magnetic field is generated when the coil 1 approaches the top part 3a of a plasma growing chamber 3, the external measurement of the coil can be reduced, and the device can be made small in side. Also, as a magnetic material 5 is arranged on the end face on the side of the microwave oscillation source 7 of the magnetic coil 1, the magnetic circuit of a dispersed magnetic lines of force is changed and also the magnetic lines of the plasma growing chamber 3, the number of turns of the coil 1, to be used to obtain the magnetic flux density required for a plasma processing, can be reduced further. As a result, the external measurement of the coil 1 can be made small, and the device can also be miniaturized further.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to CVD (Chemical Vapor D)
Electron cyclotron resonance (ECR: El
ectron Cyclotron Resonance
).

[Prior art]

Plasma devices are attracting attention not only in the semiconductor field but also in many other fields because they can perform good processing at low temperatures and low gas pressures.

FIG. 4 shows a longitudinal section of a conventional plasma device (Japanese Patent Application Laid-open No. 105234/1983).

The explanation will be given according to FIG. The base end of the waveguide 2 is connected to a microwave oscillation source 7, and an enlarged portion 2a is provided in the middle of the conduit, which enlarges toward the distal end.
The tip is open downward.

Inside the waveguide 2 is a discharge tube 30 having a hemispherical top.
is arranged concentrically with the waveguide 2, with its top extending from below to the center of the enlarged portion 2a.

A vacuum exhaust system 8 and a discharge gas supply system 9 are connected to the tube wall of the discharge tube 30. In the upper space of the discharge tube 30, a support stand 12 for holding the sample 13 is arranged with its holding surface perpendicular to the tube axis of the waveguide 2. On the outside of the waveguide 2,
Three cylindrical coils 5 each excited by a separate power source
0a to 50c are wound.

Among these, the coil 50a for generating the maximum magnetic field is connected to the waveguide 2.
The coil 5 is wound around the small cross-section portion 2b and the enlarged portion 2a.
0b is wound around the enlarged portion 2a and large cross-section portion 2c of the waveguide 2, and the coil 50c is wound around the large cross-section portion 2c of the waveguide 2. Here, the boundary between the coils 50a and 50b approximately corresponds to the top of the discharge tube 30, and the boundary between the coils 50b and 50c corresponds to the top of the support base 12.

It roughly corresponds to the number of times.

The three coils 50a to 50c have substantially equal outer dimensions, but coil 50a has substantially equal inner dimensions than coil 50b1.
The inner dimensions are smaller than the coil 50c.

A processing method for plasma processing using such an apparatus will be described below.

First, the sample 13 is carried into the discharge tube 30 and held on the support stand 12 with the surface to be treated as the upper surface. Next, the evacuation system is driven to reduce and exhaust the inside of the discharge tube 30 to a predetermined pressure, and then the discharge gas supply system 9 is driven to introduce discharge gas into the discharge tube 30, and at the same time, the evacuation system 8 is driven to properly maintain the inside of the discharge tube 30 at a predetermined processing pressure. After that, the microwave is oscillated by the microwave oscillation source 7,
This microwave is guided into the discharge tube 30 via the waveguide 2, an electric field is applied inside the tube, and the coils 50a to 50
When a magnetic field is applied by energizing C, a plasma discharge is generated in the discharge tube 30, and the discharge gas introduced by this discharge is turned into plasma, and ions and radicals are generated.

The sample 13 is processed using these ions and radicals.

[Problem to be solved by the invention]

In the conventional device, the outer dimensions of the magnetic coil are ECR
When considering the size of the magnetic field required for plasma processing, the diameter is approximately 400 to 450 fl, which increases the size of the equipment and also increases the size of peripheral equipment such as magnetic coil power supplies, making it difficult for semiconductor manufacturing processes. There were problems in terms of space, cost, etc., and it was only used as an experimental device.

For this reason, there has been a desire for a small-sized plasma device that can be applied to the actual process of semiconductor manufacturing.

The present invention has been made in view of the above circumstances, and instead of conventionally winding a plurality of cylindrical coils around a waveguide with some space left over, a single coil is wound around the waveguide. By winding along the enlarged part, and with winding to the enlarged part,
It is an object of the present invention to provide a small-sized plasma device that can be used in actual semiconductor manufacturing processes by disposing a magnetic material on the end face of the coil on the microwave oscillation source side.

[Means to solve the problem]

A plasma device according to the present invention includes a microwave oscillation source, a waveguide connected to the microwave oscillation source and having a portion that expands toward the tip side, and a hemispherical portion, the hemispherical portion being connected to the microwave oscillation source. A plasma device comprising: a plasma generation chamber installed in an enlarged part of the waveguide; a magnetic coil wound around the outside of the waveguide; and a sample chamber communicated with the plasma generation chamber. The magnetic coil is a single magnetic coil wound along the enlarged portion of the waveguide, and further, the magnetic coil is wound along the enlarged portion of the waveguide. It is a single coil, and is characterized in that a magnetic material is disposed on the end face of the microwave oscillation source of the coil.

FIG. 1 is a schematic sectional view showing an embodiment of the plasma apparatus according to the present invention, and FIG. 2 is an enlarged view of the magnetic coil l and its vicinity.

In the figure, reference numeral 2 indicates a waveguide made of a conductive material with a downwardly opened tip.The base end of the waveguide 2 is connected to a microwave oscillation source 7, and the tip is opened downward. It expands toward the other side, forming an enlarged portion. A magnetic coil 1 is wound around the outside of the expanded portion of the waveguide 2 along the expanded portion, and a magnetic material such as iron is arranged on the end face of the magnetic coil 1 on the side of the microwave oscillation source 7. has been done.

Note that the magnetic coil 1 is water-cooled by circulating water 15.

Inside the enlarged part, a hemispherical shell-shaped plasma generation chamber 3 is arranged concentrically with the waveguide 2 with its apex 3a extending from below to a position corresponding to approximately the center of the coil length of the coil 1. It is arranged in The plasma generation chamber 3 is made of an electrically insulating material that allows microwaves to easily pass through, such as quartz or Pyrex glass, and is air-cooled by a cooling system (not shown).

A sample chamber 4 is arranged below the plasma generation chamber 3. The sample chamber 4 has the shape of a hollow cube, rectangular parallelepiped, cylinder, etc., and the lower end of the plasma generation chamber 3 is joined to the open end provided on the upper surface, so that the sample chamber 4 communicates with the plasma generation chamber 3 and is kept airtight. It's hanging down.

In the sample chamber 4, a support stand 12 for holding the sample 13 is arranged with its holding surface perpendicular to the tube axis of the waveguide 2, and on the chamber wall,
A vacuum exhaust system 8 and a discharge gas supply system 9 are connected. Below the sample chamber 4, an auxiliary coil 6 supports the end surface of the support stand 1.
The waveguide 2 is disposed parallel to the holding surface of the waveguide 2 and with its axis aligned with the axis of the waveguide 2 .

Although the illustrated device uses coils with the same upper and lower external dimensions, the present invention is not limited to devices using such coils.

A processing method for plasma processing using the apparatus of the present invention will be described below, and is similar to the processing method using the conventional apparatus.

First, the sample 13 is carried into the sample chamber 4 and held on the support stand 12 with the surface to be treated as the upper surface. Next, the vacuum evacuation system is driven to evacuate the sample chamber 4 and plasma generation chamber 3 (hereinafter referred to as "both chambers") to a predetermined pressure, and then the discharge gas supply system 9 is driven to supply the discharge gas. Introduced into both chambers, the evacuation system 8 is driven to properly maintain the chambers at a predetermined processing pressure. Thereafter, the microwave oscillation source 7 oscillates microwaves, and the microwaves are guided into the plasma generation chamber 3 through the waveguide 2, and an electric field is applied inside the tube, and the coils 50a to 50c are energized to generate a magnetic field. When applied, a plasma discharge occurs, and the introduced discharge gas is turned into plasma by this discharge, and plasma ions are generated. The sample 13 is processed using these plasma ions.

Here, in the present invention, since the single magnetic coil 1 is wound around the enlarged part of the waveguide 2, the space utilization efficiency is improved and the coil approaches the top 3a of the plasma generation chamber 3. At the top part 3a where the maximum magnetic field is generated, the number of turns of the coil can be reduced to obtain the magnetic flux density required for plasma processing, so the outer dimensions of the coil are reduced and the apparatus becomes smaller.

In addition, a magnetic body 5 is arranged on the end face of the magnetic coil 1 on the side of the microwave oscillation source 7 to change the magnetic path of the dispersed magnetic lines of force so that the lines of magnetic force converge at the top 3a of the plasma generation chamber 3. Since the number of turns of the coil to obtain the magnetic flux density required for plasma processing can be further reduced, the outer dimensions of the coil are smaller and the apparatus becomes more compact.

Note that by disposing the auxiliary coil 6, the magnetic field distribution 11 in the vicinity of the sample 13 can be made uniform, making it possible to uniformly process the substrate.

3(a) to (C) show the magnetic field distribution of the device of the present invention shown in FIG. 1, the vertical axis represents the magnetic flux density B (Gauss), and the horizontal axis represents the distance Mr (from the two axes shown in FIG. 1). ms). Here, the two axes are coordinate axes that coincide with the axial center of the discharge tube 3, with the direction of the support stand being positive, and the origin being the exit portion of the plasma chamber. The same figure (al is z = −
The magnetic field distribution at 28.5 m is shown in the same figure (b) as z = O
, Otm, the same figure (C) shows the magnetic field distribution at z=180
The magnetic field distribution at m is shown.

The non-uniformity due to the magnetic field and the non-uniformity due to the electric field strength (square of the electric field) on the sample are each ±10% on a 6-inch substrate.
, ±12%. Figure 3(d) shows the magnetic field distribution on the z-axis, that is, at the point r = o. From the figure, the ECR point, that is, the point where the magnetic flux density is 875 (Gauss), is at z = -28,5 mm. The magnetic flux density B at the top of the discharge tube was 1100 (Gauss).

The specifications of the magnetic coil 1 when determining the magnetic field distribution are described below. The dimensions of each part of the device are as shown in FIG.

〔specification〕

Voltage: 26.4 (V) Current: 30.0 (A) Resistance: 0.89 (Ω) Coil cross-sectional shape: Rectangular 4 x 2 [Dragon] Coil winding length: 350 (m) Electric crab 790 ( W) A Turn: 19800 (=30 (A) X30
(Number of turns in the r direction) x 22 (Number of turns in the z direction) Coil temperature (°C): Inside 37 Inside 148 Outside 64 Cooling water amount 74.5C11 minutes Inside 6 divisions Outside According to the device of the present invention with no division, the magnetic coil The external dimensions have been reduced from the conventional device's external dimensions of 400 am to 225 fins.

〔Effect of the invention〕

In the device of the present invention, a single coil is wound along the enlarged part of the waveguide, whereas in the conventional device, multiple cylindrical coils are wound around the waveguide with some space left over. This improves space utilization and allows the coil to move closer to the top of the plasma generation chamber, reducing the number of coil turns needed to obtain the magnetic flux density required for plasma processing. The dimensions have become smaller and the device has become smaller.

In addition, by placing a magnetic material on the end face of the coil to increase the magnetic flux density at the top of the plasma generation chamber, it is possible to further reduce the number of turns of the coil, which reduces the external dimensions of the coil. , the equipment has become more compact.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional view of the device of the present invention, Fig. 2 is an enlarged cross-sectional view of the magnetic coil of the device of the present invention and its vicinity, and Fig. 3(a)
~Tdl is a graph showing the magnetic field distribution when the device of the present invention is used, and FIG. 4 is a longitudinal cross-sectional view of the conventional device. 1...Magnetic coil 2...Waveguide 3...Discharge tube 5...Magnetic material 7...Microwave oscillation source 8...Evacuation system 9...Discharge gas supply system patent applicant
Sumitomo Metal Industries Co., Ltd. Representative Patent Attorney Kono
Climb blunder 1 Figure 2 Figure 4 Figure”) lal [Gaussl 3 Figure

Claims (1)

[Claims] 1. A microwave oscillation source, a waveguide connected to the microwave oscillation source and having a portion that expands toward the tip side, and a hemispherical portion, the hemispherical shape A plasma device comprising: a plasma generation chamber disposed inside an enlarged portion of the waveguide; a magnetic coil wound around the outside of the waveguide; and a sample chamber communicated with the plasma generation chamber. , wherein the magnetic coil is a single magnetic coil wound along the enlarged portion of the waveguide. 2. A microwave oscillation source, a waveguide connected to the microwave oscillation source and having a portion that expands toward the tip side, and a hemispherical portion, and the hemispherical portion is connected to the waveguide. In the plasma device, the plasma apparatus includes a plasma generation chamber installed in an enlarged part of the waveguide, a magnetic coil wound around the outside of the waveguide, and a sample chamber communicated with the plasma generation chamber. A plasma device characterized in that it is a single coil wound along an enlarged portion of a waveguide, and a magnetic material is disposed on the end face of the microwave oscillation source of the coil.