JP2002203838A - Plasma treatment apparatus and manufacturing method of parts for the apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that heavy metal mixing in an alumite membrane scatters when an earth electrode forming the alumite membrane of a plasma treatment apparatus is exposed to plasma and adheres to a wafer performing plasma treatment and the adhered heavy metal deteriorates the characteristic of a semiconductor device. SOLUTION: At least a part of the earth electrode 114 easy to produce metal scattering by sputtering impact is covered by a high pure alumina membrane 115 by using a plasma spraying method. A metal contamination level on the wafer to be plasma-treated can be reduced to 109 pieces/cm2 or less, and the performance and reliability of an Si device can be improved.

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, and more particularly to a plasma processing apparatus for performing a plasma etching process using a corrosive gas in a process of manufacturing a semiconductor device or a liquid crystal device, and manufacturing components used in the plasma device. About the method.

[0002]

2. Description of the Related Art As a typical plasma processing apparatus used in a semiconductor manufacturing process, there is a microwave plasma etching apparatus as shown in FIG. In this apparatus, a microwave from a magnetron 200 is introduced into a plasma processing chamber 205 which is controlled by a waveguide 201, an auto tuner 202 provided on the path, and a quartz window 204 under the control of an isolator 203 and evacuated. Interaction EC between the microwave and the magnetic field formed by the plurality of coils 206
R (Electron Cyclotron Resonance) makes it possible to form low to high density plasma in a low pressure atmosphere. Gas used for etching is gas flow controller 2
Gas introduction system 208 provided with a plurality of apertures 20
Plasma processing chamber 2 through a gas distribution plate 210 having
05 is introduced. The wafer 211 is a vertically movable electrode 2
12 is fixed by an electrostatic attraction method, and bias power is applied by a high frequency power supply 213. An earth electrode 214 is provided to stably control the high frequency bias.

[0003]

The amount of heavy metal contamination of a wafer in a semiconductor manufacturing process is required to be, for example, 10 ¹⁰ / cm ² or less for Fe and Ni.
This is because when the metal element enters the semiconductor device, the performance of the element is deteriorated. In order to improve device performance and reduce costs, device design rules are being miniaturized from the 0.3 μm level to the 0.13 μm level. As device dimensions shrink, the tolerance levels for heavy metal contamination described above become stricter and 10 ⁹
It is necessary to keep the number of pieces / cm ² or less. An aluminum alloy coated with alumite is used for the ground electrode 214 of the conventional microwave plasma etching apparatus shown in FIG. However, since a NaOH aqueous solution is usually used for the degreasing treatment when forming the alumite film, a small amount of Na is mixed into the alumite film. Further, the metal element contained in the aluminum alloy is taken into the alumite film. For example, in the case of A5052, Mg is 2.2.
2.8%, Cr is 0.15 to 0.35, and these metals are mixed in the alumite film. During the etching, the metal electrode mixed in the alumite film is scattered by the impact of ions on the ground electrode 214, and has a problem that it adheres to the wafer 211. As a method of reducing Na and metal in the alumite film described above, it is conceivable to improve the alumite treatment step, particularly the cleaning step, and to use strictly controlled and high-purity aluminum material with little metal impurities. In any case, a great increase in cost is involved.

[0004]

Means for Solving the Problems At least a portion of the alumina alloy earth electrode of the plasma etching apparatus described above is coated with a high-purity alumina sprayed film to reduce the contamination level of the wafer to a level of 10 ⁹ / cm ² or less. Can be reduced stably.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to a schematic diagram of a microwave plasma etching apparatus which is one of the plasma processing apparatuses shown in FIG. explain. The basic configuration of the apparatus is basically the same as that of the conventional plasma processing apparatus shown in FIG.
01, and introduced into a plasma processing chamber 105 evacuated through a quartz window 104 controlled by an auto tuner 102 and an isolator 103 provided in the path, and an efficient plasma is formed by a magnetic field generated by a coil 106 and ECR interaction. I do. The etching gas is supplied from the gas introduction system 108 via the gas flow controller 107 to the opening 10.
Plasma processing chamber 1 through a gas distribution plate 110 having
05 is introduced. The wafer 111 is placed on a stage electrode 112 that can move up and down, and a bias is applied using a high-frequency power supply 113. An earth electrode 114 is provided to stably control the high frequency bias, and at least a part of the surface of the earth electrode 114 is covered with a high-purity alumina film 115. Next, a manufacturing process of the ground electrode 114 will be described with reference to FIGS. After manufacturing the ground electrode 300 by machining aluminum alloy (Fig. 3
(A)), an alumite film 301 is formed by anodic oxidation (FIG. 3 (b)). Subsequently, a high-purity alumina coating 302 is formed around the tip of the ground electrode by plasma spraying (FIG. 3C). The purity of the high-purity alumina material used here is 99.99% or more, and both Na and Fe are less than 10 ppm. High purity alumina coating 30
The film thickness of No. 2 is 100 μm, but a film thickness of about 50 to 200 μm can secure a sufficient life for ordinary plasma.

According to the embodiment of the present invention, since the high-purity alumina coating 115 covers the alumite-coated ground electrode 114, the scattering and release of metal are prevented, so that the metal contamination level on the wafer 111 during the etching process is reduced. 3
８8 × 10 ⁹ / cm ² .

The above-mentioned earth electrode 114 is made of an aluminum alloy having an alumite film.
It is needless to say that the metal contamination level can be similarly reduced by covering almost the entire surface of the component with the high-purity alumina film 115 when the is made of stainless steel or the like.

[0008] Another feature of the embodiment is that
When the high-purity alumina film 115 is consumed to a certain extent, the high-purity alumina film 115 remaining after wet etching or the like is used.
Is completely or partially removed, and a high-purity alumina film is overlaid and sprayed to easily regenerate the ground electrode 114.

In the above-described embodiment, the plasma is generated by the microwave. However, it goes without saying that the same effect can be obtained by another plasma discharge method using a helicon wave or the like.

[0010]

By using the plasma processing apparatus to which the present invention is applied, the level of metal contamination on the wafer to be processed can be reduced to 10 ⁹ pieces / cm ² or less. Therefore, the performance and reliability of a Si device manufactured using the plasma processing apparatus can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a plasma processing apparatus showing an embodiment of the present invention.

FIG. 2 is a schematic view of a conventional plasma processing apparatus.

FIG. 3 is a view showing a step of manufacturing a ground component according to the embodiment of the present invention.

[Explanation of symbols]

100: magnetron, 101: waveguide, 102: auto tuner, 103: isolator, 104: quartz window,
105: plasma generation chamber, 106: coil, 107: gas flow controller, 108: gas introduction system, 109: aperture, 110: gas dispersion plate, 111: wafer, 112 ...
Stage electrode, 113 high-frequency power supply, 114 earth electrode, 115 high-purity alumina film, 200 magnetron, 201 waveguide, 202 tuner, 203
.., Isolator, 204, quartz window, 205, plasma generation chamber, 206, coil, 207, gas flow controller, 208, gas introduction system, 209, aperture, 210, gas dispersion plate, 211, wafer, 212, stage electrode , 2
13: High frequency power supply, 214: Earth electrode, 300: Earth electrode, 301: Alumite film, 302: High purity alumina film.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) H05H 1/46 H05H 1/46 C H01L 21/302 B F term (Reference) 4G075 AA30 AA61 BB02 BC06 CA02 CA05 CA25 CA47 CA62 EB42 EC21 FA02 FB04 FC09 4K031 AA06 AB02 BA05 CB43 5F004 AA14 BA14 BB11 BB23 BB28 BB29 5F045 AA10 BB14 DP03 DQ10 EB03 EF05 EH17 EM09

Claims (6)

[Claims] An object of the present invention is to introduce a desired gas into a vacuum-evacuated and pressure-controlled processing chamber, generate plasma with high-frequency power, and perform plasma processing on a sample placed in the processing chamber. A plasma processing apparatus, wherein at least a part of a ground electrode is covered with a high-purity ceramic material. 2. The method according to claim 1, wherein the high-purity ceramic material covering at least a part of the ground electrode is high-purity alumina. 3. The component for a plasma processing apparatus according to claim 2, wherein the ground electrode is prepared by plasma spraying high-purity alumina on the surface of an aluminum alloy or stainless steel member. Method. 4. The component for a plasma processing apparatus according to claim 3, wherein the ground electrode is formed by plasma spraying high-purity alumina on a surface of an aluminum alloy member on which an alumite film is formed. Production method. 5. The high-purity alumina covering at least a part of the ground electrode, wherein the high-purity alumina is produced by plasma spraying using a raw material having an alumina purity of 99.99% or more. Item 5. The method for producing a component for a plasma processing apparatus according to any one of Items 2, 3, and 4. 6. The high-purity alumina covering at least a part of the above-mentioned ground electrode is made of high-purity alumina having a coating thickness of 50.
The method for producing a component for a plasma processing apparatus according to claim 2, wherein the component is produced by plasma spraying, wherein the thickness is about 200 µm.