JPS6159833A - Plasma treater - Google Patents

Abstract

PURPOSE:To inhibit side etching generated when a sample is etched by plasma by employing a gas containing chlorine by mounting a chlorine radical absorbent material where exposed tog as plasma. CONSTITUTION:A chlorine radical absorbent material 20 is fitted where exposed to the gas plama of a gas containing chlorine. An electrode 11 and an elecertrode 12 opposed each other are mounted internally in parallel in a cham ber such as a treating chamber 10 while forming a discharge space 13 and being faced in the vertical direction, and a gas dispersion chamber 14 is shaped into the electrode 11 of the elecetrodes opposed each other while a large number of gas discharge holes 15 are bored opened to the discharge space 13. A quartz plate 18 is placed on the side surface of the discharge space 13 of the electrode 12 while a discoid Cl* absorbent material 20 is fitted approximately centering around the center of the electrode 12, and the level of the surface of the Cl* absorbent material 20 is made approximately the same as the level of the sur face of the quartz plate 18. The Cl* absorbent material 20 is formed by Si, Al, C, etc. easy to absorb Cl*.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a plasma processing bag, and particularly to a plasma processing apparatus suitable for plasma etching a sample using a gas containing chlorine as an etching gas. It is something.

[Background of the invention]

As the plasma processing bag U for plasma etching a sample using a gas containing chlorine, for example, a plasma processing bag U such as that described in Japanese Patent Application Laid-open No. 185985/1985 is used.
A quartz plate that has multiple recesses on one surface in which the specimen can be placed, and a quartz plate that is made of the same material as the specimen and that is located in each of the recesses and is lower than the level of the surface of the quartz plate and has dimensions that are the same or larger than the specimen. A device is known which comprises an electrode consisting of a disc having a quartz plate and a rim made of the same material as the sample and placed around the periphery of the quartz plate.

This device is. The purpose is to improve the uniformity of etching gas, and there is no awareness of suppressing side etching.

[Purpose of the invention]

The purpose of this invention is. It is an object of the present invention to provide a plasma processing cassette capable of suppressing side etching that occurs when plasma etching a sample using a gas containing chlorine as an etching gas.

[Summary of the invention]

The present invention is characterized in that a chlorine radical absorber is provided at a location exposed to gas plasma of a chlorine-containing gas, and chlorine radicals (hereinafter abbreviated as Cr) in gas plasma after side etching are ) This is an attempt to suppress side etching by suppressing the increase in concentration.

[Embodiments of the invention]

An embodiment of the present invention will be described with reference to FIGS. 1 and 2.

In FIG. 1, in this case, a counter electrode 11 and an electrode 12 are provided in a processing chamber 10, having a discharge space 13, and facing each other in the vertical direction in parallel. A gas dispersion chamber 14 is formed inside the opposing portion 1111, and a large number of gas discharge holes 15 are formed in the discharge space 13 at a distance of m8. One end of the gas supply pipe 16 is connected to an etching gas source (not shown), and the other end thereof communicates with the gas dispersion chamber 14#2 and is connected to the opposing IE electrode 1. The counter electrode 11 is grounded in this case. The gas supply pipe 16 is provided with a valve 17 . For example, a quartz plate 1B is placed on the side surface of the discharge space 13 of the electrode 12. A power source, for example, a high frequency power source 19 is connected to the electrode 121, and the high frequency power source 19 is grounded. As shown in Figures M1 and F52, a Cla absorbing material film is formed on the area exposed to gas plasma, in this case, on the side of the discharge space 13 of the electrode 12.

In this case, the shape of the Cr absorber m is a disk, and the shape of the electrode 1
It is provided approximately centered on the center of 2. The level of the surface of the Cr absorbing material is approximately the same as the level of the surface of the quartz plate 18.
It is. The CJ' absorbing material is made of materials that easily absorb Cr, such as Si, M, and C. In this case, S
It is formed by i. Note that a vacuum evacuation system 21 is connected to the processing chamber 10.

In FIGS. 1 and 2, the inside of the processing chamber 10 is transported from the outside by a known conveying means (not shown), in this case eight samples, for example, round, AJ, All-1 to 2 samples. Si, IJ
Samples n formed of -3'It Co -1 to 2% 8i or the like are carried in and placed at the positions where the electrodes 120 are placed, with the surface to be treated facing upward. Thereafter, for example, the inside of the processing chamber 10 is evacuated to a predetermined pressure by the evacuation system 211. after that. Gas supply pipe 16 from etching gas source. CCj? supplied to the gas distribution chamber 14 via the valve 17 at a predetermined flow rate. ,, BC! ',, C! ! , etc. are discharged from the gas discharge hole 15 into the discharge space flrJ.
13, it is emitted toward the sample x. This released etching gas is pumped into the processing chamber 1 at a predetermined flow rate by the vacuum exhaust system 21.
As a result, the inside of the processing chamber IO is adjusted to a predetermined processing pressure. Thereafter, by applying a predetermined high frequency power gtiu from the high frequency power supply 19, a glow discharge is generated in the discharge space 13, whereby the etching gas is turned into plasma. The surface of sample n to be processed is etched by this gas plasma. After just etching, there is no material to be etched.
In this case, the cI in the gas plasma increases because it is absorbed by the Cr absorber.
! ``The increase in a degree is suppressed, and on the contrary, it begins to decrease.

Note that when the Cr absorbing material is not added, the electric field concentration is strong in the peripheral area of sample n, so that C, Si, etc. that have remained on the etched pattern side wall surface are decomposed and the pattern side wall surface is exposed. C I! ＊In contrast, side etch will occur.

In this embodiment, the following effects can be obtained.

(1) CI in gas plasma even if the pattern sidewall is exposed after just etching! *Since the increase in density is suppressed, side etching can be suppressed.

(2) Since side etching can be suppressed, overetching time can be extended and 1M Si residue can be removed.

(3) Side etching can be suppressed by using high frequency power and etching pressure. The range of optimal conditions for etching parameters such as etching gas flow rate is expanded.

In this example, the Cr absorbing material is provided on the side surface of the discharge space of the electrode, but C! ! *The absorbing material can be installed anywhere as long as it is exposed to gas plasma (for example, on the side of the discharge space of the counter electrode, on the wall of the processing chamber corresponding to the discharge space, or in some cases, it can be installed in the discharge space). It's okay.

〔Effect of the invention〕

As explained above, in the present invention, by providing a Cr absorbing material at a location exposed to gas plasma of a gas containing chlorine, the CI in the gas plasma after just etching is reduced. Since the increase in the 4 concentration can be suppressed, side etching can be suppressed.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the plasma processing bag δ according to the present invention, and FIG. 2 is a plan view of the electrode shown in FIG. m1. 13...discharge space, addition...cl! ``Absorbent material size 1 figure

Claims (1)

[Claims] 1. In an apparatus that uses a gas containing chlorine as an etching gas and turns the gas into plasma to etch a sample,
A plasma processing apparatus characterized in that a chlorine radical absorber is provided at a location exposed to the gas plasma.