JP2013079155A - Plasma resistant member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma resistant member excellent in strength and heat conductivity.SOLUTION: A plasma resistant member in one embodiment, which is ceramics having at least two or more phases, includes one or more kinds of oxides selected from among yttrium, zirconium and the third element, wherein each content of yttrium, zirconium and the third element is respectively, in terms of oxides, ≥40 to ≤60 mol%, ≥5 to ≤20 mol% and ≥35 to ≤50 mol%.

Description

  The present invention relates to a plasma resistant member.

  Halogen-based corrosive gases such as highly reactive fluorine and chlorine are used as low-pressure and high-density plasma sources in processes such as dry etching processes for semiconductor or liquid crystal manufacturing, CVD film formation processes, and ashing processes for removing resists. Is frequently used.

Since the low-pressure and high-density plasma has a high electron temperature and ion bombardment energy, a member that is directly exposed to the corrosive gas and the plasma is required to have high plasma resistance.
For this reason, ceramics such as high-purity alumina, aluminum nitride, yttria, yttrium aluminum garnet (hereinafter referred to as YAG) are used as members exposed to the halogen plasma in the above-described steps.

  Among these, ceramics such as yttria and YAG are particularly used in plasma processing apparatuses as materials having high corrosion resistance against corrosive gases such as halogen gas and plasma. Yttria ceramics is also used as a sintered body, but the raw materials are expensive, it is difficult to produce large-scale products and dense sintered bodies, and when used in a plasma processing apparatus, it is easily etched from the pores, There was a problem that dust was easily generated. In addition, the strength of the yttria ceramic material itself is low, and there are limitations on the apparatus members that can be used, leading to a decrease in manufacturing yield.

  In order to solve these problems, a proposal has been made to add high-strength materials such as zirconium and aluminum oxide to yttria ceramics and to have high strength and excellent corrosion resistance (see Patent Document 1).

  In addition, since yttria sintered bodies have low mechanical strength and fracture toughness values, for example, a member in which a thin film is formed on a metal substrate surface such as aluminum by thermal spraying is used as a member in an etcher (patent) Reference 2).

Yttria reacts mainly with fluorine-based gas to produce YF ₃ (melting point 1152 ° C.), and reacts with chlorine-based gas to produce YCl ₃ (melting point 680 ° C.). These halogen compounds are SiF ₄ (melting point −90 ° C.), SiCl ₄ (melting point −70) produced by reaction with quartz glass, alumina, aluminum nitride and the like, which are materials conventionally used for semiconductor manufacturing apparatus members. ° C.), AlF ₃ (melting point 1040 ° C.), AlCl ₃ (melting point 178 ° C.), and the like. For this reason, yttria exhibits stable and high corrosion resistance even when it is exposed to a halogen-based corrosive gas or its plasma.

JP 2008-273823 A JP 2002-080954 A

  The yttria ceramic described in Patent Document 1 is excellent in plasma resistance and strength, but has a very low thermal conductivity and cannot be used in a high-temperature apparatus. Furthermore, there is a risk that yttria ceramics are damaged by thermal shock during operation of the apparatus, and the fragments become particles and cause contamination. Moreover, since the sintering method is hydrogen firing, a very large equipment is required, which increases the manufacturing cost.

  The yttria sprayed film as described in Patent Document 2 has many pores, and when exposed to plasma, leads to generation of particles on the wafer. Further, when there are pores penetrating to the base material, they do not function as a protective film. Moreover, there exists a possibility that the property excellent in the high plasma property which a yttria may have may be deteriorated by adding an additive.

  The present invention has been made to solve the above technical problem, and an object thereof is to provide a plasma-resistant member having excellent strength and thermal conductivity.

  The plasma-resistant member of one aspect is a ceramic having at least two phases and includes at least one oxide selected from yttrium, zirconium, and a third element, and the yttrium, zirconium, and the third element. Each element is characterized by being 40 mol% or more and 60 mol% or less, 5 mol% or more and 20 mol% or less, and 35 mol% or more and 50 mol% or less in terms of oxide.

  The third element of the plasma-resistant member of one embodiment is desirably one or more elements selected from aluminum, scandium, niobium, samarium, ytterbium, erbium, hafnium, and cerium.

  The plasma-resistant member of one aspect includes a first solid solution of yttrium oxide and one or more oxides of aluminum, scandium, niobium, samarium, ytterbium, and erbium among the yttrium oxide and the third element. At least 2 selected from a second solid solution of yttrium oxide and zirconium oxide, and a third solid solution of yttrium oxide, zirconium oxide and one or both oxides of hafnium and cerium among the third elements. Desirably, certain compounds are included.

  In one embodiment, the plasma-resistant member includes 40 to 60 mol% of the yttrium oxide, 5 to 20 mol% of the zirconium oxide, 35 to 50 mol% of aluminum oxide, hafnium oxide, scandium oxide, and oxidation. Desirably, a granulated powder containing neodymium, niobium oxide, samarium oxide, ytterbium oxide, erbium oxide, and one or more compounds selected from cerium oxide is fired in an air atmosphere or a reducing atmosphere.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the plasma-resistant member which is excellent in plasma resistance, is high intensity | strength, and does not lose thermal conductivity.

  The plasma-resistant member according to one aspect of the present invention is a ceramic having at least two phases including yttrium, zirconium and a third element. Yttrium, zirconium and the third element X (yttrium: zirconium: third element) are 40 mol% or more and 60 mol% or less, 5 mol% or more and 20 mol% or less, 35 mol% or more and 50 mol% or less, respectively, in terms of oxide. Examples of the third element X include one or more selected from aluminum, scandium, niobium, samarium, ytterbium, erbium, hafnium, and cerium. This plasma-resistant member has excellent plasma resistance, high strength, and high heat conductivity.

  Yttrium oxide is excellent in plasma resistance, but has not so high properties such as bending strength, fracture toughness and thermal conductivity. Therefore, yttrium oxide is one or more oxides selected from zirconium oxide, aluminum oxide, hafnium oxide, scandium oxide, neodymium oxide, niobium oxide, samarium oxide, ytterbium oxide, erbium oxide and cerium oxide. A material prepared by adding a raw material to which an oxide of element 3 is added to have a specific composition ratio is fired to obtain a ceramic.

  The phase contained in the plasma-resistant member of one aspect depends on the type and ratio of the oxide of the raw material of the plasma-resistant member, but yttrium oxide, aluminum of the yttrium oxide and the third element, scandium, niobium , Samarium, a first solid solution of one or more oxides of ytterbium and erbium, a second solid solution of yttrium oxide and zirconium oxide, yttrium-stabilized zirconia, yttrium oxide, zirconium oxide, and third And at least two compounds selected from a third solid solution of one or both of hafnium and cerium.

  The phase contained in the plasma-resistant member can be examined by X-ray diffraction measurement. The composition contained in the plasma-resistant member is measured by ICP emission spectroscopic analysis or inductively coupled plasma mass spectrometry and is calculated in terms of oxide.

When aluminum is used as the third element X, the plasma-resistant member of one aspect includes at least Y ₃ Al ₅ O ₁₂ and YAlO ₃ as the first solid solution, and the first solid solution is one aspect of the first element. It becomes 50 mol% or more of the plasma resistant member. When at least one of aluminum, scandium, niobium, samarium, ytterbium, and erbium is used as the third element X, Y ₃ X ₅ O ₁₂ and YXO ₃ are at least included in one embodiment of the plasma-resistant member. These are contained in an amount of 50 mol% or more of the plasma-resistant member of one embodiment. When either one or both of hafnium and cerium is used for the third element X, the plasma-resistant member according to one aspect includes at least 50 mol% or more as the third solid solution.

One aspect of the plasma-resistant member is an etch rate (unit time) when the plasma-resistant member made of 100% yttrium oxide shown in Comparative Example 9 below is exposed to CF ₄ / CHF ₃ plasma generated with a plasma source power of 100 W. When the per unit erosion depth is 1.0, the etch rate is 1.1 or less. If the etch rate is 1.1 or less, the excellent plasma resistance of 100% yttrium oxide is not lost, which is preferable from the viewpoint of preventing contamination of the object to be processed. If the etch rate is 1.0 or less, the plasma resistance is preferably 100% yttrium oxide or more.

  The plasma resistant member of one embodiment has a bending strength of 150 MPa or more. When the bending strength is less than 150 MPa, the usable member may be restricted from the viewpoint of strength, and it is not preferable that there is a possibility of breakage during the manufacturing process of the semiconductor device or the like. The bending strength in the present invention is a four-point bending strength defined by JIS R1601. When the bending strength is 200 MPa or more, it is preferable that the possibility of breakage can be further reduced.

  The plasma resistant member of one embodiment has a thermal conductivity (W / mK) of 5.0 W / mK or more. When the thermal conductivity is 5.0 or more, it is preferable that the process conditions are less limited and the thermal shock resistance is excellent. The thermal conductivity in the present invention is a value defined by JIS R1611. When the thermal conductivity is 5.5 W / mK or more, the process time is reduced and the cost is reduced. Moreover, the temperature unevenness of the member does not occur and there is no fear of local etching.

  The plasma-resistant member of one embodiment preferably has an open porosity of 1.0 or less. When the open porosity is 1.0 or less, it is more preferable that the plasma-resistant member is denser and has an excellent etch rate. The open porosity is a value obtained by a cross-sectional image analysis method from a microphotograph having a magnification of 200 to 500 times.

  Yttrium oxide contained in the raw material of the plasma-resistant member of one embodiment is 40 mol% or more and 60 mol% or less of the raw material. When the amount of yttrium oxide is less than 40 mol% of the raw material, the plasma resistance is remarkably lowered regardless of the content of the third component. On the other hand, when there is more yttrium oxide than 60 mol% of a raw material, heat conductivity will fall. The yttrium oxide contained in the raw material of the plasma-resistant member of one embodiment is preferably 50 mol% or more and 55 mol% or less of the raw material because a member having excellent plasma resistance, bending strength, and thermal conductivity can be obtained.

  Zirconium oxide contained in the raw material of the plasma-resistant member of one embodiment is 5 mol% or more and 20 mol% or less of the raw material. When the amount of zirconium oxide is less than 5 mol% of the raw material, the plasma resistance and the thermal conductivity are lowered regardless of the contents of yttrium oxide and the third component. On the other hand, when there is more zirconium oxide than 20 mol% of a raw material, bending strength will fall. Zirconium oxide contained in the raw material of the plasma-resistant member of one embodiment is preferably 10 mol% or more and 20 mol% or less of the raw material because a member having excellent plasma resistance, bending strength, and thermal conductivity can be obtained.

  The oxide of the third element contained in the raw material of the plasma-resistant member of one embodiment is 35 mol% or more and 50 mol% or less of the raw material. When the oxide of the third element is less than 35 mol% of the raw material, the bending strength and the thermal conductivity are lowered. On the other hand, when the amount of the third element oxide is more than 50 mol% of the raw material, the plasma resistance and the thermal conductivity are lowered. The yttrium oxide contained in the raw material of the plasma-resistant member of one embodiment is preferably 35 mol% or more and 40 mol% or less of the raw material because a member having excellent plasma resistance, bending strength, and thermal conductivity can be obtained.

When the yttrium: third element of the plasma-resistant member of one embodiment is 1: 0.67 to 1.25, there is an advantage that the melting point is lowered and the density is further increased.
Further, when yttrium: zirconium is 95: 5 to 80:20, there is an advantage that the melting point is lowered and densification is performed, and both strength and plasma resistance are improved.

Next, the manufacturing method of the plasma-resistant member of 1 aspect is demonstrated.
In one embodiment, the plasma-resistant member includes 40 to 60 mol% of the yttrium oxide, 5 to 20 mol% of the zirconium oxide, 35 to 50 mol% of aluminum oxide, hafnium oxide, scandium oxide, and oxidation. A raw material containing one or more compounds selected from neodymium, niobium oxide, samarium oxide, ytterbium oxide, erbium oxide and cerium oxide is pulverized and mixed with a ball mill or the like, if necessary, and dispersed uniformly. obtain. More preferable raw materials are 50 mol% to 55 mol% of the yttrium oxide, 5 mol% to 10 mol% of the zirconium oxide, 35 mol% to 40 mol% of aluminum oxide, hafnium oxide, scandium oxide, neodymium oxide, niobium oxide. , Samarium oxide, ytterbium oxide, erbium oxide, and a mixture containing one or more of the compounds selected from cerium oxide.

The obtained slurry is dried and granulated with a spray dryer to obtain, for example, granulated powder having an average particle size of 10 μm or more and 50 μm or less. For example, a molded product is obtained by CIP molding (cold isostatic press molding) of the obtained granulated powder at a pressure of 1 ton / cm ² . You may process a molded object as needed.

  Next, the molded body is fired in an air atmosphere or a reducing atmosphere. The firing temperature is preferably 1600 ° C. or higher and 1800 ° C. or lower in any atmosphere. The reducing atmosphere is preferably a hydrogen gas atmosphere containing hydrogen gas or an inert gas. When firing in an air atmosphere, the open porosity of the plasma-resistant member can be 2.0 or less. When fired in a reducing atmosphere, the open porosity can be 1.0 or less.

The materials shown in Table 1 are mixed for 5 hours or more in a ball mill containing a resin and uniformly dispersed to obtain a slurry. The obtained slurry is dried and granulated with a spray dryer to obtain granulated powder having an average particle size of 10 μm or more and 50 μm or less. A molded body is obtained from the obtained granulated powder by CIP molding at a pressure of 1.5 ton / cm ² . The molded body is processed into a plate shape of 100 mm × 100 mm × 10 mm. The processed molded body is fired at 1750 ° C. for 5 hours in a hydrogen atmosphere.

  The etch rate, bending strength, and thermal conductivity of the obtained fired body are measured by the methods described above. The results are summarized in Table 1.

As shown in Table 1, the thermal conductivity decreases if the composition ratio is out of the range even if three components are included. Further, if any one of the three components is out of the range, any one of the etch rate, bending strength, and thermal conductivity is reduced. Therefore, it can be understood that the composition ratio of the present invention is a major factor in determining the etching rate, strength, and conductivity even if the same material is used.

  The present invention is suitably used as a plasma resistant semiconductor member.

Claims (4)

At least two-phase ceramics,
Including one or more oxides selected from yttrium, zirconium and a third element,
The said yttrium, the said zirconium, and the said 3rd element are 40 mol% or more and 60 mol% or less, respectively 5 mol% or more and 20 mol% or less, 35 mol% or more and 50 mol% or less in conversion of an oxide, The plasma-resistant member characterized by the above-mentioned. The plasma-resistant member, wherein the third element is at least one element selected from aluminum, scandium, niobium, samarium, ytterbium, erbium, hafnium and cerium.   A first solid solution of yttrium oxide, yttrium oxide and the third element of aluminum, scandium, niobium, samarium, one or more oxides of ytterbium and erbium, and a first solid solution of yttrium oxide and zirconium oxide. And at least two compounds selected from the group consisting of a solid solution of 2 and a third solid solution of one or both of hafnium and cerium oxides of yttrium oxide, zirconium oxide, and the third element. The plasma-resistant member according to claim 1 or 2. 40 mol% or more and 60 mol% or less of the yttrium oxide, 5 mol% or more and 20 mol% or less of the zirconium oxide, 35 mol% or more and 50 mol% or less of aluminum oxide, hafnium oxide, scandium oxide, neodymium oxide, niobium oxide, samarium oxide, oxidation The granulated powder containing one or more kinds of the compounds selected from ytterbium, erbium oxide, and cerium oxide is fired in an air atmosphere or a reducing atmosphere. 2. The plasma-resistant member according to item 1.