JPS63219128A - Treatment apparatus - Google Patents

Abstract

PURPOSE:To improve the treatment speed and uniformity by providing a high permeability member in the vicinity of the extraction port of a plasma transporting path from a plasma generating chamber to a treatment chamber, thereby obtaining a magnetic field distribution suitable for a sheet-type treatment. CONSTITUTION:A microwave is introduced from a waveguide 5a through a quartz plate 8 into a plasma chamber 1a. The degree of vacuum of the chamber 1a is maintained while a raw material gas for treatment is introduced into the chamber 1a from a gas introducing pipe 7a. If, now, a magnetic field is applied to the chamber 1a by a magnetic coil 4a, the gas satisfies the electron cyclotron condition and causes a plasma. The magnetic field generated in the central part by the coil 4a is diffused at an extraction port 9 by a high permeabillity member 3a, and thus, the plasma is diffused reaching a sample 6a. And the magnetic field distribution can easily be changed with ring thickness of the member 3a. With this, a magnetic field distribution suitable for a sheet- type treatment is obtained, thereby improving the treatment speed and uniformity.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention utilizes the physical and chemical effects of ions and radicals generated by plasma to etch substrates (hereinafter referred to as wafers) one by one. The present invention relates to a processing apparatus suitable for forming a film using a chemical vapor deposition method, and relates to a processing apparatus suitable for forming fine patterns and thin films such as LSI.

In particular, we utilize the force of a magnetic field that controls the distribution (intensity, direction, polarization, etc.) of plasma generated by microwave discharge by electron cyclotron resonance (hereinafter referred to as ECR) using a highly permeable member. Uninow's processing equipment has excellent processing uniformity and minimal damage.

An etching apparatus will be described below as a representative example.

Conventional technology In the manufacturing process of semiconductor LSI, patterns become finer.

With the trend toward higher integration, thinner films, and an increase in the number of process steps, anisotropic and low-damage etching methods and devices are required.

In response to this, ECR of gas raw materials containing norogen elements
There is a method of etching a wafer by generating plasma using a plasma. Plasma created using ECR can separate the plasma generation part from the Ueno etching part, and
Since the generated plasma can be controlled and etched using electric and magnetic fields, damage can be suppressed to a low level.
The spread of plasma can also be controlled and the uniformity of processing can be improved.

Among them, several methods of controlling plasma using a magnetic field have been proposed, but a method with a simple structure was published in Japanese Patent Application Laid-open No. 57-13.
It is described in Publication No. 3636 and Japanese Patent Publication No. 58-13626.

A conventional processing device will be described below with reference to the drawings.

EC is performed in the plasma generation chamber 1 by the microwave introduced into the plasma generation chamber 1 through the waveguide 6 and the magnetic coil 4.
Generate plasma using R.

A cover (outer case) 3 made of a high magnetic permeability material is provided that extends from around the magnetic coil 40 to around the processing chamber 2, and this cover adjusts the magnetic field distribution inside the processing chamber 2 to draw out the plasma. On the other hand, Si wafers 6, which are samples to be processed, are arranged vertically on the inner circumference of the processing chamber 2, and the surface of the Si wafers 6 is irradiated with plasma extracted by the cover 3 made of the high magnetic permeability material. to form a film.

Problems to be Solved by the Invention However, in the above-described configuration, there is a gap in the processing chamber 2 that plays an important role in drawing out the plasma from the plasma generation chamber 1, changing the direction of the plasma flow, and processing with good uniformity. Since the cover 3 made of a high magnetic permeability material covers the magnetic coil 40, the magnetic field strength and distribution of the magnetic coil 4
It is almost determined by the magnetic field strength generated, making it difficult to obtain a magnetic field distribution and magnetic field strength suitable for processing.

For example, the magnetic field strength generated by the magnetic coil 4 has a frequency of 2
．． In order to satisfy the ECR conditions using microwaves of 45 GHz, a magnetic field of approximately 875 Gauss is required in the magnetic coil 4, and if the field deviates from 875 Gauss, no matter how large or small, plasma will not be generated. The 6"-magnetic field strength in the processing chamber 2 located directly below the plasma generation chamber 1 is determined by the magnetic field strength of the magnetic circuit formed by the magnetic coil 4, that is, the magnetic field conditions that satisfy ECR. Therefore, In the conventional configuration, the direction of the plasma flow drawn from the plasma generation chamber 1 within the processing chamber 2 can be greatly changed, and the magnetic field distribution and intensity optimal for processing the Si wafer 6 with good uniformity and efficiency can be controlled by the plasma. In addition, as shown in Japanese Patent Application Laid-Open No. 57-133636, it is difficult to control the magnetic field strength separately from the magnetic field strength for generating the magnetic field. It is virtually impossible to measure and process the material into an appropriate shape.

Furthermore, in the dry ethoching process, an end point detector is used to reduce the variation in processing between wafers.
Single-wafer processing apparatuses that etch wafers one by one are becoming mainstream, but in conventional apparatuses, as can be seen from FIG. 2, the magnetic field within the processing chamber 2 is distributed such that it is low in the center and high in the periphery. Therefore, the plasma is strongly attracted to the outer periphery and becomes too wide, and the plasma density becomes thinner in the center, resulting in an etching rate and etching rate distribution that are inappropriate for a single-wafer type device.

The present invention solves the above-mentioned conventional problems.The present invention has a simple structure to control the plasma distribution in the processing chamber, and the magnetic field distribution in the processing chamber can be easily changed. The object of the present invention is to provide a processing apparatus that can obtain a uniform distribution and is excellent in both processing speed and processing uniformity.

Means for Solving the Problems In order to solve the above problems, the processing apparatus of the present invention includes a plasma generation chamber that generates plasma by the action of microwaves and a magnetic field, and a plasma generation chamber that generates plasma by polar diffusion caused by the magnetic field. In a processing apparatus in which plasma is introduced into the processing chamber, a highly permeable member is installed around the side surface of the plasma transport path from the plasma generation chamber to the processing chamber or near the exit of the transport path (inlet of the processing chamber).

The magnetic field distribution for plasma transport can be changed simply by changing the thickness of the highly permeable material.

Hereinafter, an example will be described in which the present invention is applied to dry etching. However, the present invention relates to a method of transporting plasma, and similar effects can be obtained when applied to CVD using plasma.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a processing apparatus in an embodiment of the present invention. In FIG. 1, 1a is a plasma generation chamber, 2a is a processing chamber, 3a is a highly permeable member (carbon steel; 5S41P),
4a is a magnetic coil, 5a is a waveguide, 6a is a sample (processed object), 7a is a gas introduction pipe, 8 is a quartz plate, 9 is a plasma extraction port, 10 is a chamber and a lid of the processing chamber (S
US-316; non-magnetic).

The operation of the processing device configured as described above will be explained below. Microwave generator (hereinafter referred to as magnetron, not shown) The microwave frequency is, for example, 2
．． Microwaves generated at a frequency of 45 GHz) are applied to the plasma generation chamber 1a through a quartz plate 8 by a waveguide 5a.

A raw material gas for processing is introduced into the plasma generation chamber 1a through a gas introduction pipe 7, and the chamber is evacuated by a turbo molecular pump (not shown) to maintain a vacuum level of 1 to 10 mTorr. At the same time, the magnetic coil 4a installed on the outer periphery of the plasma generation chamber 1a causes the plasma generation chamber 1
When a magnetic field of 875 Gauss is applied to a, the gas in the plasma generation chamber satisfies the ECR conditions and enters a plasma state, becoming electrons, ions, radicals, etc.

The magnetic lines of force in the plasma generation chamber 1a inside the magnetic coil 4a are almost parallel, and the plasma is drawn out in parallel, but below the plasma extraction port 9, the lines of magnetic force are spread out due to the influence of the highly permeable member 3a. Therefore, the plasma also spreads due to bipolar diffusion and reaches the sample 6a. However, since the highly permeable member 3a is separated from the magnetic coil 4a and does not reach the opposite pole side of the magnetic coil 4a (above the magnetic coil 4a in FIG. 4), a closed magnetic circuit is not created and the radiation is moderately dispersed. A magnetic field is formed within the processing chamber 2a.

Therefore, the generated plasma is bipolarly diffused by the magnetic field as described above, reaches the sample 6a, and processes its surface.

In the processing device configured as described above, the magnetic coil 4a
A magnetic field of 875G (Gauss) is generated at the center of the plasma extraction port 9, and Ni plating (thickness 1Q/
A ring made of a highly permeable material (carbon steel; 5S41P) coated with 1 m) was varied in thickness between 10 and 40 rMlO, and the change in magnetic field strength at the sample 6a position was measured using a Gaussmeter. In FIG. 3, the thickness of the highly permeable member 3a is 10
, 20.40 (other materials are non-magnetic materials such as stainless steel (SUS316), copper, aluminum, quartz, etc.).

From this result, the distribution of the magnetic field at the sample position can be easily changed simply by changing the thickness of the highly permeable material near the plasma extraction port.

10 be.

The second example will be described below.

In the apparatus used in the first embodiment, SF6 gas is flowed through the gas introduction pipe 7a at a rate of 2QCC per minute, and while the vacuum level is maintained at 6mTorr by exhausting with a turbo molecular pump, 2.45GH2 gas is supplied from the magnetron (not shown). Microwave (
400 W) was introduced into the plasma generation chamber 1a through the waveguide 5a, and a magnetic field of 875 Gauss was applied by the magnetic coil 4a to generate plasma.

On the other hand, the sample to be processed was prepared by heating a 5 inch diameter Si single crystal wafer to 900'C to form a 3102 film of 1000 layers, and then using a CVD (chemical vapor deposition) method to form a polycrystalline Si single crystal wafer.
3,000 polySi (polySi) films were formed, a photoresist was applied (thickness: 1.2 μm), a pattern was exposed and developed, and etching was performed on the polySi film.

Although the etching results are slightly affected by the gas flow in the processing chamber 2a, the etching rate distribution almost matches the magnetic field distribution in Example 1a, and when the thickness of the highly permeable member 3a made of 5S41 is 10 mm. The etching speed was fast in the center and slowed toward the periphery. When the thickness of the high magnetic permeability member 3a is 40, the etching speed is faster at the periphery and slightly slower at the center, contrary to when the thickness is 10. On the other hand, when the high magnetic permeability member 3a had a thickness of 20 times, it was possible to uniformly etch almost the entire surface, and the uniformity was 2.1%.

Next, a third embodiment of the present invention will be described.

In the apparatus used in the second embodiment, CHF3 containing 10 parts of 02 instead of SF6 was used as the etching gas.
8102 film 2 was processed using the pyrogenic method at 900° C. as a sample to be processed.
000, and then photoresist (1,2 μm
Si wafer 6 on which a pattern was coated, exposed and developed
A was used.

The etching results were the same as in the second example.

On the other hand, for comparison, the processing chamber 2a from the processing apparatus in FIG.
The high magnetic permeability material 3a inside is removed, and in its place, a high magnetic permeability member 3a made of 5S41 with a thickness of 10 m+n is attached along the entire circumference from the upper end surface of the magnetic coil 4a to the side surface and further to the lower side surface of the processing chamber 2a. Etching was carried out using the gas processing sample of the third example in the same manner as in the example, but the etching rate was extremely low and the etching rate distribution was such that the outer periphery of the Si wafer 6a was etched. The central part was hardly etched.

A fourth embodiment will be described below with reference to FIG.

In Fig. 4, 1b is a plasma generation chamber, 2b is a processing chamber, 3b is a ring-shaped highly permeable member 3b made of carbon steel 5S41P, 4b is a magnetic coil, 5b is a waveguide, and 6b is an object to be processed (sample ), 7 is the gas introduction quartz tube, 10b is the chamber and lid of the processing chamber (stainless steel 5US-3
1ey), 11 is a quartz Pelger, and 12 is a plasma transport path (in the same Pelger as the plasma generation chamber 1b).
, 13 is a spacer (made of copper) for adjusting the height of the magnetic coil 4b.
, 14 is a quartz Pelger 10 cylindrical protection tube (SUS-3
16).

The operation of the processing device configured as described above is as follows. First, 2.45 GHz microwaves generated by a magnetron (not shown) are applied to the quartz Pelger 11 through the waveguide 6. Furthermore, plasma is generated in the quartz chamber 11 by maintaining the pressure inside the quartz Pelger 11 at 1 to 10 mTorr using a turbo molecular pump while introducing a magnetic field of 875 Gauss from the magnetic coil 4 and gas through the quartz tube 7b into the quartz Pelger 11. (at the plasma generation section 1b). Because the lines of magnetic force are parallel around the magnetic coil 4b, particles such as ions and electrons in the plasma generated due to the effect of bipolar diffusion form a plasma transport path 12 (a path with the same diameter as the plasma generation chamber 1b inside the quartz Pelger 11). ) flows down inside.

However, a highly permeable member 3b is installed near the end of the plasma transport path 12 (at the outer periphery of the protective tube 14 of the quartz Pelger 11), and the lines of magnetic force are widened (some are attracted to the highly permeable material). As the plasma spreads, it reaches the sample 6 and is processed.

Using the above device, a magnetic field of 875 Gauss 14. was changed to 1Q, 20, and 40 brains, and the magnetic field distribution at the height of sample 6 was measured with a Gaussmeter, and the results were very similar to the results shown in FIG. 3 of the first example. All magnetic field measurements were conducted under atmospheric pressure.

Further, 30 CC/min of CHF3 gas containing 10% oxygen was flowed through the quartz Pelger 11 through the quartz tube 7b, and while maintaining the degree of vacuum at 6 mTorr, microwaves of 2.45 GH2 were applied to generate plasma in the plasma generation chamber 1b. (The outside of the quartz Pelger 11 is at atmospheric pressure.

). Etching was carried out using the same sample as in the third example, and the etching results were the same as in the third example.

Effects of the Invention As described above, the present invention allows the plasma distribution within the processing chamber to be easily changed by installing a highly permeable material near the exit of the plasma transport path (inlet of the processing chamber) or the side surface of the transport path. 15 ・Can be processed uniformly and efficiently using a single-wafer system.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a processing apparatus according to a first embodiment of the present invention, and FIG. 2 is a sectional view of a conventional plasma low-temperature deposition apparatus.
FIG. 3 is a diagram showing the measurement results of the magnetic field distribution in the first embodiment of the present invention, and FIG. 4 is a sectional view of the processing apparatus in the fourth embodiment of the present invention. 1a, 1b...Plasma generation chamber, 2a, 2b.
...Processing chamber, 3a, 3b...High magnetic permeability material, 4a. 4b...Magnetic coil, sa, 5b...
Waveguide, 6a. 6b...Sample (object to be processed), 7a, 7b...
・Gas introduction pipe, 8...Quartz plate, 9...
...Plasma extraction port, 1Q...Chamber and lid of the processing chamber, 11...Quartz Pel jar, 12...Plasma transport path. Name of agent: Patent attorney Toshio Nakao and 1 other person14
Open eyes UG3-219128 (6) Fig. 4 b b 1 Cow b A 2

Claims (2)

[Claims] (1) It has at least a plasma generation chamber and a processing chamber, in which plasma is generated in a vacuum by the action of microwaves and a magnetic field, and the plasma is transferred to the vacuum processing chamber by using gradients in magnetic field strength. In a processing apparatus for processing the surface of an object to be processed, a highly magnetically permeable member is installed near a plasma transport path from a plasma generation chamber to a processing chamber, and the objects to be processed are introduced into the processing chamber one by one. A processing device characterized by processing. (2) The processing apparatus according to claim 1, wherein the high magnetic permeability member is installed so as to surround the entire circumference of the plasma transport path in a ring shape.