JP2002037683A - Plasma resistant element and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low cost plasma resistant element and its manufacturing method having high plasma resistant property also excellent in mechanical properties such as bending strength and toughness. SOLUTION: This plasma resistant element 15 is characterized by having a base material 13 consisting of a ceramics group sintered body and a fluoride layer 14 of the thickness 1 to 100 μm containing not less than one kind of element selected from the periodic table IIA group elements and IIIA group elements formed on the surface of the above base material 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a plasma-resistant member and a method of manufacturing the same, and more particularly, to a plasma-resistant member exhibiting excellent plasma resistance in a halogen-based corrosive gas atmosphere and a method of manufacturing the same. .

[0002]

2. Description of the Related Art In a semiconductor device manufacturing process, an etching apparatus or a sputtering apparatus for performing fine processing on a semiconductor wafer or a C for forming a film on a semiconductor wafer is used.
VD devices and the like are used. These manufacturing apparatuses employ a configuration having a plasma generating mechanism for the purpose of high integration. For example, as schematically shown in FIG. 2, a helicon wave plasma etching apparatus is known.

In FIG. 3, reference numeral 1 denotes an etching chamber having an etching gas supply port 2 and a vacuum exhaust port 3, and an antenna 4, an electromagnet 5, and a permanent magnet 6
Is installed. In the processing chamber 1, a lower electrode 8 supporting a semiconductor wafer 7 is disposed. In addition,
The antenna 4 is connected to a first high-frequency power supply 10 via a first matching network 9, and the lower electrode 8 is
A second high frequency power supply 12 is connected to a second high frequency power supply 12 via a second matching network 11.

[0004] Etching by this etching apparatus is performed as follows. That is, after the semiconductor wafer 7 is placed on the surface of the lower electrode 8 and the inside of the processing chamber 1 is evacuated, an etching gas is supplied. Thereafter, a high-frequency current having a frequency of 13.56 MHz flows from the high-frequency power supply 10 and 12 to the antenna 4 and the lower electrode 8 via the corresponding matching networks 9 and 11. On the other hand, a high-density plasma is generated by applying a current to the electromagnet 5 to generate a magnetic field in the processing chamber 1. The etching energy is decomposed into an atomic state by the plasma energy, and the film formed on the surface of the semiconductor wafer 8 is etched.

In this type of manufacturing apparatus, a corrosive gas such as a chlorine-based gas such as boron chloride (BCl) or a fluorine-based gas such as fluorocarbon (CF ₄ ) is used as an etching gas. The inner wall of room 1,
Components that are exposed to plasma in a corrosive gas atmosphere, such as a microwave introduction window, a monitoring window, and a lower electrode 8, are required to have plasma resistance. In response to such demands,
Alumina-based sintered bodies, silicon nitride-based sintered bodies, aluminum nitride-based sintered bodies, and the like are used as the plasma-resistant members.

[0006]

However, plasma-resistant members such as the above-mentioned alumina-based sintered bodies, silicon-nitride-based sintered bodies, and aluminum-nitride-based sintered bodies gradually become exposed to plasma in a corrosive gas atmosphere. Corrosion progresses, and crystal particles constituting the surface are detached, so-called particle contamination occurs. That is, there is a problem that the detached particles adhere to the surface of the semiconductor wafer 7, the lower electrode 8, and the like, adversely affect the quality and precision of the film formation, and the performance and reliability of the semiconductor are easily impaired.

[0007] Further, in a CVD apparatus, corrosion resistance is required since the CVD apparatus is exposed to a fluorine-based gas such as fluorine nitride (NF ₃ ) during cleaning.

In order to solve the above-mentioned problem of corrosion resistance, a plasma-resistant member made of a sintered body of yttrium aluminate garnet (so-called YAG) has been proposed (Japanese Unexamined Patent Publication No. Hei 10 (1998)).
No. 236871). That is, the surface exposed to plasma in a halogen-based corrosive gas atmosphere has a porosity of 3%.
A plasma-resistant member formed of the following yttrium aluminate garnet-based sintered body and having a surface having a center line average roughness (Ra) of 1 μm or less is known.

However, this yttrium aluminate garnet-based sintered body is excellent in plasma resistance, but has a problem that mechanical strength such as bending strength and fracture toughness is poor. Here, the poor mechanical strength (brittleness, etc.) means that the member is liable to be damaged or damaged in the course of, for example, a cleaning operation, and is combined with the fact that the material itself is relatively expensive. This leads to an increase in the manufacturing cost of the manufacturing apparatus or the semiconductor.

The present invention has been made in view of the above circumstances, and a low-cost type plasma-resistant member having high plasma resistance and excellent mechanical strength such as bending strength and toughness, and the like. The purpose is to provide a manufacturing method.

[0011]

Means for Solving the Problems According to the present invention, there is provided a substrate selected from the group consisting of a group IIA element and a group IIIA element of a periodic table formed on a surface of the substrate. Thickness 1 to 1000 containing at least one element
A plasma-resistant member having a fluoride layer of μm.

According to a second aspect of the present invention, in the plasma resistant member according to the first aspect, the ceramic-based sintered body is an alumina-based sintered body.

According to a third aspect of the present invention, in the plasma resistant member according to the first or second aspect, the fluoride layer is formed mainly of yttrium fluoride.

According to a fourth aspect of the present invention, there is provided a ceramic sintered body on which a fluoride containing at least one element selected from the group consisting of a group IIA element and a group IIIA element of the periodic table has a thickness of 1 to 1000 μm. A method for manufacturing a plasma-resistant member, characterized in that the member is deposited to a film thickness of:

According to a fifth aspect of the present invention, in the method for manufacturing a plasma-resistant member according to the fourth aspect, the means for depositing the fluoride film is a plasma spraying method.

The inventions of claims 1 to 5 are based on the following findings. (A) For oxides such as yttrium aluminate garnet, yttrium fluoride is formed and deposited on the surface when exposed to fluorine-based plasma, and aluminum-oxygen bonds are maintained if the yttrium fluoride is deposited and remaining. As a result, it exhibits high corrosion resistance. (B) The corrosion resistance due to the deposition of the fluoride layer is about several times that of the ceramic sintered body (base material). (C) Sufficient corrosion resistance is obtained when the thickness (depth from the surface) of the deposited fluoride layer exceeds about 1 μm. (D) The fluoride layer can be easily deposited by a sputtering method, a plasma spraying method, a vapor deposition method, or the like.

In the first to sixth aspects of the present invention, the ceramic base material may be, for example, an alumina-based sintered body, a zirconia-based sintered body, a silicon nitride-based sintered body, or an aluminum nitride-based sintered body. High strength is required. The shape, size, material and the like are appropriately selected and set depending on the purpose of use, the place of use, and the like.

Here, a typical alumina-based base material (sintered body) is a sintering aid such as magnesia, for example.
ア ル ミ ナ 1% by weight, and is substantially composed of alumina, and the average grain size of the sintered body crystal is preferably 5 μm or more, more preferably 5.5 to 20%.
It is about 0 μm, more preferably in the range of 10 to 40 μm. Thus, it is desirable to appropriately adjust the particle size so that a sprayed film or the like can be easily formed.

Incidentally, this kind of ceramic base material can be manufactured by the following means. For example, an average particle size of 0.1
A raw material powder is prepared by adding and compounding a sintering aid and the like to alumina particles of about 1.0 μm. Next, after granulating the raw material powder, for example, isostatic pressing, extrusion molding, injection molding,
It is molded by molding means such as casting, and the molded body is subjected to calcination and degreasing. Thereafter, the molded body subjected to the calcining and degreasing treatment is subjected to a heat treatment in an atmosphere containing hydrogen gas, thereby firing and sintering the molded body.

In the first to fifth aspects of the present invention, the fluorinated substance deposited, coated and formed on the surface of the ceramic base material is at least one member selected from the group consisting of a group IIA element and a group IIIA element of the periodic table. It is a fluorine compound containing an element. Here, examples of the fluorine compound include calcium fluoride, magnesium fluoride, barium fluoride, yttrium fluoride, scandium fluoride, lanthanum fluoride, cesium fluoride, yttrium fluoride aluminate garnet, and two or more of these. Of mixed systems.

The deposition and formation of this kind of fluoride layer is performed by a general sputtering method, plasma spraying method, vapor deposition method, or the like. That is, the corresponding fluoride is used as a sputtering source, a plasma spraying source, or an evaporation source, and the required energy is applied to deposit and form a fluoride layer on the surface of the ceramic base material. However, in order to easily secure a sufficient film thickness, a plasma spraying method is preferable.

In the first to fifth aspects of the present invention, the thickness of the fluorinated layer deposited and formed on the surface of the ceramic base material must be selected within the range of 1 to 1000 μm. That is, if the thickness is less than 1 μm, the required plasma resistance cannot be sufficiently provided, and
The thickness of the fluoride layer is selected within the above range, more preferably in the range of 10 to 150 μm, since the effect is the same even if the thickness exceeds the above, which hinders the cost reduction.

According to the first to third aspects of the present invention, a structure is employed in which the substrate is formed of a ceramic sintered body and the surface exposed to plasma is coated with a fluoride layer. That is,
By using a ceramic-based sintered layer with excellent mechanical strength such as bending strength and fracture toughness as the base material, the surface exposed to plasma is covered with a fluoride layer with excellent plasma resistance, The occurrence of damage or breakage in a cleaning operation or the like is eliminated, and the possibility of particle contamination is also eliminated.

Therefore, the present invention effectively contributes to the production and processing of semiconductors having high performance and reliability without adversely affecting the quality and precision of film formation, while suppressing the increase in the production cost of the production apparatus or semiconductor. I do.

According to the fourth and fifth aspects of the present invention, a ceramic-based sintered body having excellent mechanical strength such as bending strength and fracture toughness is used as a base material, while a fluoride layer having excellent plasma resistance is exposed to plasma. It is possible to provide a plasma-resistant member having a configuration in which the surface is covered with good yield and mass production.

[0026]

An embodiment will be described below with reference to FIG.

Alumina particles 100 having an average particle diameter of 0.3 μm
An appropriate amount of ion-exchanged water and 2% by weight of polyvinyl alcoholate are added to a composition system in which MgSO ₄ .7H ₂ O is converted to magnesia with respect to the weight%, and the mixture is stirred and mixed to prepare a slurry. Next, the prepared slurry was granulated with a spray drier, and the obtained granulated powder was subjected to isostatic pressing (CIP press).
Formed under a pressure of 807 × 10 ⁵ MPa (1000 kgf / cm ² ), thickness 30 mm, width 30 mm, length 30 m
m were obtained.

Each of the above-mentioned molded products was exposed to air at 900 ° C.
After the calcination and degreasing treatments were performed at a temperature of, a sintering and firing treatment was performed at a temperature of 1790 ° C in a hydrogen gas atmosphere to produce an alumina-based sintered body (base material). The alumina sintered body was identified by X-ray diffraction (XRD), and was a dense sintered body having an average crystal particle diameter of about 10 to 40 μm.

Next, a yttrium fluoride layer 14 is deposited and formed on the alumina sintered body 13 using a plasma spraying apparatus. FIG. 1 is a cross-sectional view illustrating a schematic configuration of the plasma resistant member 15 manufactured as described above.

The cross section of the alumina sintered body having the yttrium fluoride layer deposited and formed on the surface was observed and imaged with an electron microscope. As a result, the entire surface of the substrate 1, which was substantially an alumina sintered body, It was confirmed that the plasma-resistant member was covered with the yttrium fluoride layer having a substantially uniform thickness. The thickness of the deposited / formed layer of yttrium fluoride was a dense layer of 1 μm.

A 10 × 10 mm square test piece was cut out from the sintered body covered with the yttrium fluoride layer,
When the fracture toughness was measured, it was about 4 MN / m ^3/2 , which was comparable to the fracture toughness value of the alumina-based sintered body. Furthermore, a thickness of 2 mm, 10 × 10 mm was formed from the sintered body, with one main surface being covered with an yttrium fluoride layer.
A corner test piece was cut out, attached to a parallel plate RIE apparatus, and subjected to a plasma exposure test under the following conditions.

That is, the flow rate of the fluorocarbon (CF4) gas is 100 cc / min, and the supply power Ps / Pb = 500 W
/ 40 W, ion impact energy 88 eV, plasma density 1.7 × 10 ¹¹ atoms / cm ³ , gas pressure 4 × 1
When a plasma exposure test was performed under the conditions of 33 Pa (4 mTorr), the etching rate (angstrom / angstrom /
Time) was 300. This value is １ ／ of the value obtained when the fluoride layer was not deposited on the surface of the alumina-based sintered body was about 900, indicating about three times the corrosion resistance.

In the above, yttrium fluoride was plasma sprayed, but instead of yttrium fluoride, calcium fluoride, magnesium fluoride, barium fluoride, yttrium fluoride, scandium fluoride, lanthanum fluoride, cesium fluoride Except that each was used, as in the case of the above specific example, on the alumina-based sintered body surface,
Corresponding fluoride layers were deposited and formed to produce six types of plasma resistant members.

A 10 × 10 mm square test piece was cut out from each of the sintered bodies coated with the calcium fluoride layer and the like, and the fracture toughness was measured. The results were all about 4 MN / m ^3/2. The value was comparable to the fracture toughness value of the sintered body. Further, from the sintered body, one main surface is coated with a fluoride layer to have a thickness of 2 m.
Each of the test pieces having a size of 10 × 10 mm square was cut out, attached to a parallel plate type RIE apparatus, and subjected to a plasma exposure test under the same conditions as described above, and the etching rate (angstrom / hour) was determined. Show. In this comparative test, the corrosion resistance was calcium fluoride,
It turns out that magnesium fluoride and barium fluoride are particularly excellent.

[0035]

[Table 1]

When the cross section of each of the plasma-resistant members of Examples 2 to 7 was observed and imaged with an electron microscope before being exposed to plasma, the entire surface was covered with the corresponding layer of fluoride. It was confirmed that it was an alumina-based plasma resistant member. The surface of each of these sintered bodies is covered with a dense fluoride layer having a thickness of about 1 to 10 μm, and the average crystal grain size of the alumina base material is 10 to 10 μm.
It was about 50 μm. If plasma spraying of 10 μm or more is performed, the entire sprayed film can be formed with a sufficient film thickness, so that it can be used safely even under severe conditions.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the invention. For example, the ceramic-based substrate may be another ceramic-based sintered body instead of the alumina-based sintered body, and further, the type of the sintering aid, the composition ratio of these additional components, and the like may vary depending on the application of the plasma-resistant member. -It may be appropriately selected according to the purpose of use. Further, the same plasma resistant member can be obtained even if the deposition, formation or introduction of the fluoride layer is performed not by the plasma spraying method but by a sputtering method or an evaporation method.

[0038]

According to the first to third aspects of the present invention, a ceramic-based sintered body having excellent mechanical strength such as bending strength and fracture toughness is used as a base material, while the surface exposed to plasma is made to have plasma resistance. The structure is covered with an excellent fluoride layer. Therefore, the occurrence of damage or breakage in a cleaning operation or the like is eliminated, and there is no possibility of causing particle contamination.

That is, while suppressing an increase in the cost of manufacturing a semiconductor manufacturing apparatus or a semiconductor, it is possible to effectively contribute to the manufacturing and processing of a semiconductor having high performance and reliability without adversely affecting the quality and precision of film formation. Plasma resistant member can be provided.

According to the fourth and fifth aspects of the present invention, the mechanical strength such as bending strength and fracture toughness is excellent, and the plasma resistance is also excellent. It can be offered in mass production.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of a plasma-resistant member according to an embodiment.

FIG. 2 is a sectional view showing a schematic configuration of a CVD apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Etching chamber 2 ... Etching gas supply port 3 ... Vacuum exhaust port 4 ... Antenna 5 ... Electromagnet 6 ... Permanent magnet 7 ... Semiconductor wafer 8 ... Lower electrode 9,11 ... Mating work 10, 12 high frequency power supply 13 alumina base material 14 fluoride 15 plasma resistant member

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Keiji Morita 30 Soya, Hadano-shi, Kanagawa Toshiba Ceramics Co., Ltd. (72) Inventor Masahiko Ichijima 30 Soya, Hadano-shi, Kanagawa Toshiba Ceramics Co., Ltd. (72) Inventor Hiroko Ueno 30 Soya, Hadano-shi, Kanagawa Toshiba Ceramics Co., Ltd.Hadano Office (72) Inventor Shuichi Saito 33, Shinisogo-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Toshiba Corporation Inside the Technical Center (72) Katsuaki Aoki 33, Shinisogo-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside the Toshiba Production Technology Center (72) Eriko Nishimura 33, Shinisogo-cho, Isogo-ku, Yokohama-shi, Kanagawa Corporation F-term in Toshiba Production Technology Center (reference) 4K029 AA07 BA42 BC01 CA01 CA05 5F004 AA15 AA 16 BA20 BB13 BB29 5F045 AA08 AC00 BB15 EB03 EC05 EH08 EM09

Claims (5)

[Claims] A substrate comprising a ceramic sintered body,
Group IIA elements and II of the periodic table formed on the substrate surface
A plasma-resistant member having a fluoride layer having a thickness of 1 to 1000 μm containing at least one element selected from the group of IA group elements. 2. The plasma-resistant member according to claim 1, wherein the ceramic sintered body is an alumina-based sintered body. 3. The plasma resistant member according to claim 1, wherein the fluoride layer is formed mainly of yttrium fluoride. 4. A fluoride containing at least one element selected from the group consisting of a group IIA element and a group IIIA element of the periodic table having a thickness of 1 to 1000 on the surface of the ceramic sintered body.
A method for producing a plasma-resistant member, characterized in that the member is deposited to a thickness of μm. 5. The method according to claim 4, wherein the means for depositing the fluoride film is a plasma spraying method.