JP2007063595A - Ceramic gas nozzle made of y2o3 sintered compact - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ceramic gas nozzle which is superior in plasma resistance and does not produce particle dust. <P>SOLUTION: The ceramic gas nozzle made of a Y<SB>2</SB>O<SB>3</SB>sintered compact has an inner surface of an as-fired state, on which a halogenous corrosive gas passes; and an outer surface which is exposed to the halogenous corrosive gas or the plasma of the halogenous corrosive gas, and is roughened into the surface roughness of 1 μm or more by Ra. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a ceramic gas nozzle made of a Y ₂ O ₃ sintered body. For example, the present invention relates to a ceramic gas nozzle made of a Y ₂ O ₃ sintered body suitable for use in a plasma processing apparatus or a semiconductor / liquid crystal manufacturing plasma apparatus.

  Various reaction gases are used in the semiconductor manufacturing process. A gas nozzle is used to uniformly introduce these reaction gases into the chamber.

  Conventionally, quartz glass, aluminum anodized, high-purity alumina ceramics, and the like have been used as the material for the gas nozzle. Among these, alumina ceramics are often used because they are superior to other materials in terms of plasma resistance. In the case of a material with poor plasma resistance, not only particles and contamination are generated, but the dimensional change of the nozzle diameter is remarkably large. Therefore, particularly in a thin film forming apparatus such as a CVD apparatus, a change in the nozzle diameter adversely affects film thickness control and uniformity within the wafer surface.

However, with the miniaturization of LSIs, demands for generation of particles, contamination, and the like, and changes in the shape of nozzle holes are becoming stricter. With the alumina ceramic nozzles that have been used frequently, it has become difficult to satisfy such strict requirements.
JP 10-45461 A JP 2000-247726 A

  The problem is the plasma resistance of the nozzle material itself.

  For example, the etcher uses a lot of highly corrosive halogen gas, and with the miniaturization of the wiring, the plasma density has increased, and consumption of the constituent materials in the chamber has become a major problem. .

  Similar problems occur in thin film forming apparatuses such as CVD apparatuses. In the thin film forming apparatus, when the film forming reaction process is continued, reaction product films are attached to various surfaces of various parts in the reaction furnace. If this reaction product film is left as it is, it grows gradually, and the reaction product film comes off due to the effects of thermal expansion difference between the reaction product film and the substrate, vibration, and gas flow. If the peeled-off material adheres to the wafer, the manufacturing yield of the semiconductor element is significantly reduced.

Conventionally, when the predetermined number of film forming processes has been exceeded, the apparatus is stopped, the chamber is opened, and the films adhering to various surfaces of each part are cleaned, but recently, plasma cleaning, that is, Plasma cleaning, in which a gas such as NF ₃ is introduced into the chamber for every fixed film forming process to generate plasma and cleaning, has become the mainstream.

In the case of plasma cleaning, many exposures are made to highly corrosive NF ₃ gas. As a result, the dimensional change of the nozzle diameter, which is the most important for the nozzle, has occurred to a degree that cannot be ignored in alumina ceramics.

  Another problem is the generation of particles and dust from the alumina nozzle.

  Most of the particles generated from the nozzle are alumina particles. In particular, particles are often generated in the initial stage of use. Some particles are generated due to insufficient cleaning, but most of the particles are alumina particles that have fallen from the processing crush layer on the ground surface along with the gas flow.

  The reaction product film attached to the outer surface of the nozzle may peel off and become dust.

  An object of the present invention is to provide a ceramic gas nozzle which is excellent in plasma resistance and does not generate particle dust.

  Examples of the solving means of the present invention are as follows.

(1) A ceramic gas nozzle made of a sintered body of Y ₂ O ₃ , wherein the inner surface where the halogen corrosive gas flows is a fired surface and is exposed to the halogen corrosive gas or the plasma of the halogen corrosive gas. The Y ₂ O ₃ sintered ceramic gas nozzle, wherein the surface is roughened to a surface roughness Ra of 1 μm or more.

(2) The Y ₂ O ₃ sintered ceramic gas nozzle described above, wherein the density of the Y ₂ O ₃ sintered body is 4.83 g / cm ³ or more.

(3) The Y ₂ O ₃ sintered ceramic gas nozzle described above, wherein the surface roughness Ra of the outer surface is 1 μm or more.

(4) The Y ₂ O ₃ sintered ceramic gas nozzle described above, wherein the outer surface is roughened by blasting.

  According to the present invention, the ceramic gas nozzle has high corrosion resistance against the halogen-based corrosive gas and its plasma, can prevent the generation of particles, and can contribute to the improvement of the yield of semiconductor chips and liquid crystal panels. .

The gas nozzle made of Y ₂ O ₃ sintered ceramics has much better corrosion resistance against halogen plasmas such as F-based and Cl-based than the gas nozzle made of sintered alumina ceramics. Moreover, since the inner surface through which the gas passes remains as a fired surface, there is no processed fracture layer. Furthermore, since the outer surface to which the reaction product film adheres is roughened, the adhesion between the reaction product film and the substrate is high, and it does not easily peel off. Therefore, the initial nozzle dimensions can be maintained over a long period of time, particle dust can be reduced, and the manufacturing process can be stabilized and the yield can be improved.

As a result of intensive studies to solve the problems of the prior art as described above, the inventors of the present invention are the ceramic gas nozzle made of a Y ₂ O ₃ sintered body having a relative density of 96% or more, and the inner surface through which the reaction gas flows. It was found that a ceramic gas nozzle whose surface was roughened to a surface roughness Ra of 1 μm or more by sandblasting or the like was effective.

In the ceramic gas nozzle of the present invention, it is preferable that the density of the Y ₂ O ₃ sintered body is 4.83 g / cm ³ or more. When the density is less than 4.83 g / cm ³ , pores remain in the sintered body, etching due to the pores becomes remarkable, dimensional change is likely to occur, and particles are likely to be generated.

  The method for measuring the density is in accordance with JIS R1634 “Method for measuring the density and open porosity of fired fine ceramics”.

  The roughening of the outer surface is preferably carried out by blasting such as sand blasting, shot blasting or grit blasting. This is because the surface can be roughened at a low cost, and partial roughening can be easily performed by masking or the like.

  The surface roughness of the outer surface is preferably Ra 1 μm or more. If it is less than this, the anchor effect between the reaction product film and the base material is small, and it becomes easy to peel off.

  Generally, the surface roughness is measured by a method defined in JIS B0601 or the like.

Ion exchange water and a binder were added to a 99.9% pure Y ₂ O ₃ raw material to form a slurry, which was then granulated with a spray dryer to obtain granulated powder. The obtained granulated powder was molded at a pressure of 1500 kgf / cm ² into a nozzle shape to obtain a base processed product. The base processed product was calcined at 900 ° C. to disperse the binder, and then fired in a hydrogen atmosphere at 1800 ° C. The inner surface through which the reaction gas passes was left as a fired surface, and the outer surface was roughened by blasting. The density of the fired body was measured by a method defined in JIS R1634.

  A set of 8 nozzles prepared as shown in Table 1 was attached to a plasma CVD apparatus to form a film. The dimensions of the nozzle were an outer diameter of 7 mm, an inner diameter of 5 mm, and a length of 60 mm. Particles on a 200 mm diameter wafer were measured with a laser particle counter. Nozzle wear was performed by dimensional measurement and surface observation.

  As is clear from Table 1, in the example of the present invention, the generation of particles is small and the amount of material consumption due to plasma is small. Therefore, it is possible to suppress fluctuations in dimensions important for the nozzle, such as the nozzle diameter. Therefore, the semiconductor manufacturing process such as film formation can be stabilized and the yield of the semiconductor element can be improved.

When the density was less than 4.83 g / cm ³ , the number of particles increased even when the inner surface remained a fired surface and the outer surface was roughened. This is because the plasma concentrates the pores.

As described above, according to the above-described embodiment of the present invention, the gas nozzle is made of Y ₂ O ₃ ceramics having a density of 4.83 g / cm ³ or more, the inner surface through which the reaction gas passes is left as the fired surface, and the outer surface Since the surface is roughened by blasting, nozzle consumption due to corrosive plasma is reduced, and generation of particles and dust can be suppressed. As a result, the yield of semiconductor elements can be improved. It was.

Claims (4)

A ceramic gas nozzle made of a Y ₂ O ₃ sintered body, wherein an inner surface through which a halogenated corrosive gas flows is an as-fired surface, and an outer surface exposed to the halogen corrosive gas or plasma of the halogenated corrosive gas is rough. A Y ₂ O ₃ sintered ceramic gas nozzle, characterized in that it is planarized. _Y 2 _{O 3} sintered ceramic gas nozzle according to claim 1, the density of the Y ₂ O ₃ sintered body is characterized in that at 4.83 g / cm ³ or more. _3. The Y ₂ O ₃ sintered ceramic gas nozzle according to claim 1, wherein the outer surface has a surface roughness Ra of 1 μm or more. The Y ₂ O ₃ sintered ceramic gas nozzle according to any one of claims 1 to 3, wherein an outer surface is roughened by a blast treatment.