WO2016186365A1 - Low-resistance silicon carbide ceramic material using atmospheric sintering scheme and method for manufacturing same - Google Patents

Abstract

The present invention relates to a silicon carbide ceramic material using an atmospheric sintering scheme, which is dense, which has excellent corrosion resistance and chemical resistance against plasma, which has an excellent thermal conductivity and a low thermal expansion ratio such that there is little concern of fracturing even when used for a long period of time, which has a low resistance such that arc generation can be suppressed inside a plasma atmosphere of etching equipment, which can be manufactured at a low cost and thus is economical, and which can be employed for a jig of semiconductor equipment, and a method for manufacturing the same. The present invention provides a method for manufacturing a silicon carbide ceramic material using an atmospheric sintering scheme, the method comprising: a material/raw material providing step for mixing alpha silicon carbide (α-SiC) powder or beta silicon carbide (β-SiC) powder and a liquid sintering agent at a predetermined ratio, thereby providing raw material powder; a slurry step for processing the raw material powder, which has been provided in the material/raw material providing step, into slurry; a drying/granulation step for drying and granulating the raw material powder, which has been processed into slurry in the slurry step; a molding step for molding the raw material powder, which has been granulated in the drying/granulating step, in a predetermined shape; a degreasing step for vacuum-degreasing the molded body, which has been molded in the molding step; and a sintering step for sintering the molded body, which has undergone the degreasing step.

Description

Low resistance silicon carbide ceramic material using atmospheric pressure sintering method and its manufacturing method

The present invention relates to a low-resistance silicon carbide ceramic material using the atmospheric pressure sintering method and a method of manufacturing the same. More particularly, the present invention relates to a compact, excellent corrosion resistance and chemical resistance to plasma, low thermal conductivity, and low coefficient of thermal expansion. The present invention relates to a low-resistance silicon carbide ceramic material using an atmospheric pressure sintering method which can be manufactured at low cost, is economical, and can be employed in a jig for semiconductor equipment, and a method of manufacturing the same.

Silicon carbide has excellent oxidation resistance and chemical stability, excellent mechanical properties such as mechanical strength, hardness, and wear resistance, high thermal conductivity, and electrically semiconductor characteristics, so it is a high temperature structural material, a part of semiconductor process equipment, heater, and gas dust. It is widely used in a wide range of fields such as wear-resistant parts such as filters, mechanical seals, heat sinks of LED equipment, and is also partially used as power semiconductors and thermoelectric elements by controlling electrical and thermal characteristics.

In such silicon carbide, solid phase sintering and liquid phase sintering methods using ordinary silicon carbide powder as a raw material are known as a sintering method of a bulk material.

Among them, as a solid-phase sintering method of silicon carbide, boron (B) and carbon (C) are added to the silicon carbide powder as a sintering aid, and after general mixing and molding of ceramics, the pressure is sintered at 2050 ° C or higher. Sintering at temperature produces a silicon carbide sintered body having a sintered density of at least 95%. The silicon carbide material added with boron and carbon has a disadvantage in that volume resistivity is about 10 ³ to 10 ⁵ Ωcm, and electrical conductivity is too low, so that it is difficult to perform electric discharge machining to manufacture a complicated shape or a large part.

On the other hand, the liquid phase sintering method of silicon carbide is shown in US Patent No. 4,829,027 and US Patent No. 5,580,510. In summary, the manufacturing method proposed in these patents, the liquid phase at a high temperature as a sintering aid to the silicon carbide powder Oxides, mixtures of oxides or oxides and aluminum nitrides are added at the same time to undergo general mixing and molding of ceramics, followed by sintering at 1750 ° C or higher by atmospheric sintering or pressure sintering, resulting in melting of the sintering aid during the sintering process. The liquid phase formed promotes densification with a liquid phase sintering mechanism to produce a silicon carbide sintered body having a sintered density of 3.0 g / cm ³ or more. Since the silicon carbide material thus prepared contains an excess of liquid phase, the volume resistivity is about 10 ³ to 10 ⁷ Ωcm, which is not a good electrical conductor, causing unwanted arcs in the plasma atmosphere of the etching equipment for semiconductor manufacturing.

Therefore, the present invention has been proposed to solve the above-mentioned conventional problems, and the inventor of the present invention is derived from the results of repeated studies and experiments, and it is compact and has excellent corrosion resistance and chemical resistance to plasma, and high thermal conductivity. It has good thermal expansion rate, so there is little risk of breakage even in long-term use, and low resistance, it is possible to suppress the generation of arc in the plasma atmosphere of the etching equipment, and it is economical because it can be manufactured at low cost. An object of the present invention is to provide a low-resistance silicon carbide ceramic material using a pressureless sintering method that can be employed in a jig, and a method of manufacturing the same.

The problems of the present invention are not limited to those mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

According to an aspect of the present invention for achieving the above object, preparing a raw material for preparing a raw material powder by mixing a predetermined ratio of alpha silicon carbide (α-SiC) powder or beta silicon carbide (β-SiC) powder and liquid sintering aid step; Slurry step of slurrying the raw material powder prepared in the raw material preparation step; Dry granulation step of drying and granulating the raw material powder of the slurry in the slurry step; A molding step of molding the raw powder granulated in the dry granulation step into a predetermined form; A degreasing step of vacuum degreasing the molded body formed in the forming step; And a sintering step of sintering the molded body subjected to the degreasing step. A method of manufacturing a low resistance silicon carbide ceramic material using an atmospheric pressure sintering method is provided.

In one aspect of the invention, in the raw material preparation step, the mixing ratio of the alpha silicon carbide (α-SiC) powder or beta silicon carbide (β-SiC) powder and liquid sintering aid is alpha silicon carbide (α-SiC ) Powder or beta silicon carbide (β-SiC) powder is preferably 79.0% to 99.0% by weight, 1.0% to 21.0% by weight of the liquid sintering aid.

In one aspect of the invention, the liquid sintering aid is preferably made of a mixture of aluminum nitride (AlN) and yttria (Y ₂ O ₃ ).

In one aspect of the invention, the mixing ratio of the aluminum nitride and yttria is preferably 0.5 to 10.0% by weight aluminum nitride, 0.5 to 20.5% by weight yttria.

In one aspect of the invention, the slurry step is added to 200 parts by weight of ethanol solvent with respect to 100 parts by weight of the raw material prepared in the raw material preparation step, 0.5 to 1.5 parts by weight of dispersant and 1 to 3 parts by weight of binder and oxidation It is preferable to include zirconium ball (ZrO ₂ Ball) to put together ball milling for 4 to 24 hours.

In one aspect of the invention, the dry granulation step includes withdrawing the raw material slurried in the ball mill of the raw material preparation step to dry and granulate using a spray dryer (Spray Dryer) equipment, the molding The step preferably includes molding at a pressure of 300 to 1,500 kgf / cm ² using a molding die.

In one aspect of the invention, after the molding step, it is preferable to further include a secondary molding step of performing cold isostatic pressing (CIP: Cold Isostatic Press) at a pressure of 2,000kgf / cm ² .

In one aspect of the present invention, the degreasing step includes the step of heating up to 800 ℃ in a vacuum atmosphere to remove the binder contained in the molded body, the sintering step is a graphite work box in the atmospheric pressure sintering furnace It is preferable to include sintering at a temperature of 1,850 to 2,050 ° C for 1 to 8 hours while flowing nitrogen (N ₂ ) gas or argon (Ar) gas using a graphite work box.

According to another aspect of the invention, the volume resistivity value of 1.7 × 10 ^-2 ~ 6.5 × 10 ² Ω · Cm manufactured by the method of manufacturing a low resistance silicon carbide ceramic material using the atmospheric pressure sintering method according to the above aspect A silicon carbide ceramic material having is provided.

According to the low-resistance silicon carbide ceramic material and its manufacturing method using the atmospheric pressure sintering method according to the present invention, there is an effect that can provide a ceramic material that is dense, excellent in corrosion resistance and chemical resistance to plasma, and good thermal conductivity.

In addition, the present invention can be suitably employed in the jig of the semiconductor etching equipment, and the thermal expansion rate is low, there is little risk of damage even in the long-term use, it is possible to manufacture at a low cost there is an effect that can be economical advantages.

In addition, since the low-resistance silicon carbide ceramic material of the present invention is low-resistance, it is possible to suppress the generation of arc in the plasma atmosphere of the etching equipment, which is suitable for long-term use.

The effects of the present invention are not limited to those mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

1 is a flow chart showing a method of manufacturing a low resistance silicon carbide ceramic material using the atmospheric pressure sintering method according to the present invention;

2 is a SEM (scanning electron microscope) × 300 photograph of a sintered body fracture surface of a low resistance silicon carbide ceramic material using the atmospheric pressure sintering method according to the present invention;

3 is a SEM (scanning electron microscope) × 3000 photograph of the sintered body fracture surface of the low-resistance silicon carbide ceramic material using the atmospheric pressure sintering method according to the present invention;

4 is a scanning electron micrograph showing the surface of the specimen of Example 5 according to the plasma etching test, and

5 to 7 are scanning electron micrographs showing the surfaces of the specimens of the comparative examples according to the plasma etching test.

Further objects, features and advantages of the present invention can be more clearly understood from the following detailed description and the accompanying drawings.

Prior to the detailed description of the present invention, the present invention may be variously modified and may have various embodiments, and the examples described below and illustrated in the drawings are intended to limit the present invention to specific embodiments. It is to be understood that the present invention includes all modifications, equivalents, and substitutes included in the spirit and technical scope of the present invention.

In addition, in the description with reference to the accompanying drawings, the same components regardless of reference numerals will be given the same reference numerals and duplicate description thereof will be omitted. In the following description of the present invention, if it is determined that the detailed description of the related known technology may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

Hereinafter, a low-resistance silicon carbide ceramic material and a manufacturing method thereof using the atmospheric sintering method according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

First, a method of manufacturing a low resistance silicon carbide ceramic material using the atmospheric pressure sintering method of the present invention will be described with reference to FIG. 1. 1 is a flowchart illustrating a method of manufacturing a low resistance silicon carbide ceramic material using an atmospheric pressure sintering method according to the present invention.

The method of manufacturing a low resistance silicon carbide ceramic material using the atmospheric pressure sintering method according to the present invention, as shown in Figure 1, alpha silicon carbide (α-SiC) powder or beta silicon carbide (β-SiC) powder and liquid phase sintering Raw material preparation step of preparing a raw material powder by mixing a predetermined ratio (S100); Slurry step (S200) for slurrying the raw material powder prepared in the raw material preparation step; Dry granulation step (S300) for drying and granulating the raw material powder of the slurry in the slurry step; A molding step of molding the raw material granulated in the dry granulation step into a predetermined form (S400); Degreasing step (S500) of vacuum degreasing the molded body formed in the molding step; And a sintering step (S600) for sintering the molded body subjected to the degreasing step.

A detailed description of each step is as follows.

Alpha silicon carbide (α-SiC) in a raw material preparation step (S100) of preparing a raw material powder by mixing a predetermined ratio of alpha silicon carbide (α-SiC) powder or beta silicon carbide (β-SiC) powder and a liquid sintering aid. The mixing ratio of the powder or beta silicon carbide (β-SiC) powder and the liquid sintering aid is 79.0 wt% to 99.0 wt% of the alpha silicon carbide (α-SiC) powder or beta silicon carbide (β-SiC) powder, and the liquid sintering aid 1.0 It is provided as the weight%-21.0 weight%.

Here, the liquid sintering aid is provided as a liquid sintering aid composed of aluminum nitride (AlN) and yttria (Y ₂ O ₃ ) by a predetermined ratio. At this time, it is preferable that the mixing ratio of aluminum nitride and yttria is 0.5 to 10.0 wt% of aluminum nitride and 0.5 to 20.5 wt% of yttria.

Here, the volume resistivity can be adjusted by changing its content in the composition range of the liquid sintering aid, in which the volume resistivity can be adjusted in the range of 10 ⁻³ to 10 ⁺⁴ Ω · Cm, more than this. If larger, the properties of the non-conductor becomes larger, and arc generation becomes larger. If smaller, the properties of the conductor become large and the high-frequency beam is scattered.

Specifically, if the mixing ratio is not provided above, the desired resistance value cannot be obtained. If the mixing ratio is out of the upper limit, it is difficult to realize corrosion resistance, chemical resistance, strength, thermal conductivity, etc., which are inherent in silicon carbide, Outside of this, the fine microstructure cannot be obtained and the density is significantly lowered, so it cannot be used as a ceramic material.

Slurry step (S200) for slurrying the raw material powder prepared in the raw material preparation step, adding 200 parts by weight of ethanol solvent with respect to 100 parts by weight of the raw material prepared in the raw material preparation step, 0.5 to 1.5 parts by weight of a dispersant and 1 to 3 parts by weight of the binder and about 50% of the volume of the ball mill container zirconium oxide (ZrO ₂ Ball) is put together to perform a ball milling for a predetermined time, preferably 4 to 24 hours. Here, 50% of the ball mill vessel volume means 50% of the space volume inside the ball mill vessel, and the total volume of the plurality of zirconium oxide balls is 50% of the ball mill vessel volume.

Dry granulation step (S300) for drying and granulating the raw material powder made of the slurry in the slurry step, drying equipment such as a spray dryer by drawing the raw material slurried in the ball mill of the raw material preparation step Dry and granulate with.

Subsequently, the molding step (S400) of molding the raw material powder granulated in the dry granulation step into a predetermined form is performed at a pressure of 300 to 1,500 kgf / cm ² using a molding die (primary molding).

Here, the present invention further includes a secondary forming step (S700) of performing cold isostatic pressing (CIP: Cold Isostatic Press) at a pressure of 2,000 kgf / cm ² after the forming step (S400). The execution of the hydrostatic press (secondary molding) makes the molded body more compact by secondary molding.

Next, the degreasing step (S500) of vacuum degreasing the molded body formed in the molding step includes removing the binder contained in the molded body while gradually warming up to 800 ° C. in a vacuum atmosphere.

The sintering step (S600) for sintering the formed body after the degreasing step is embedded in a normal pressure furnace, using a graphite work box (Graphite work box), or (N-embedding) in the nitrogen (N-embedding) state (N) ₂ ) Sinter at 1,850 to 2,050 ° C for 1 to 8 hours while flowing gas or argon (Ar) gas (preferably, 3 to 5 ml / min).

Since the sintering does not proceed below the sintering temperature, it is difficult to implement the desired density, and thus, the characteristics of the silicon carbide material cannot be realized, and the characteristics of the silicon carbide material cannot be realized due to oversintering above the sintering temperature.

Example

According to an embodiment of the present invention, alpha, beta SiC powder, yttria, aluminum nitride powder was mixed to prepare a composition for producing low-resistance silicon carbide ceramics. The composition was put into a polypropylene ball mill, and zirconia balls were subjected to ball milling for 12 hours using 200 parts by weight of ethanol as a solvent based on 100 parts by weight of the raw material.

No	SiC (α) wt%	SiC (β) wt%	AlN wt%	Y 2 O 3 wt%
One	89.26	-	2.3	8.44
2	86.57	-	2.88	10.55
3	83.88	-	3.46	12.66
4	-	89.26	2.3	8.44
5	-	86.57	2.88	10.55
6	-	83.88	3.46	12.66

The mixture was molded, degreased, and sintered to prepare specimens, and measured density and volume resistivity. In particular, sintering was carried out in nitrogen atmosphere and argon atmosphere.

	No	Density (g / cm 3 )	Volume resistivity (Ωcm)
N 2	One	3.0648	2.2 X 10 2
	2	3.1844	6.1X10 2
	3	3.1890	6.5X10 2
	4	3.0156	1.0X10 -1
	5	3.2324	9.6X10 -2
	6	3.2781	1.7X10 -2
Ar	One	3.1512	1.5X10 2
	2	3.2314	3.3 X 10 2
	3	3.2723	2.3 X 10 1
	4	3.1643	1.0X10 1
	5	3.2584	8.8
	6	3.2851	5.8

According to the results of Table 2, it can be seen that a low-resistance silicon carbide material having excellent plasma corrosion resistance having a volume resistivity value of 1.7 × 10 ⁻² to 6.5 × 10 ² Ω · Cm may be produced depending on the amount of liquid and the gas atmosphere. have.

2 and 3 are scanning electron micrographs of the low-resistance silicon carbide ceramic material using the atmospheric pressure sintering method according to the present invention as described above, Figure 2 is a low-resistance silicon carbide ceramic using the atmospheric pressure sintering method according to the present invention Sintered body fracture surface SEM (scanning electron microscope) x 300 photograph of the material, Figure 3 is a sintered body fracture surface SEM (scanning electron microscope) x 3000 photograph of the low-resistance silicon carbide ceramic material using the atmospheric pressure sintering method according to the present invention.

In addition, the results of the plasma etching test of the specimen of Example 5 and other materials are shown in Table 3 and Table 4, the composition of Example 5 is 86.57 wt% SiC (β), 2.88 wt% AlN and Y ₂ O ₃ 10.55 wt%.

In Table 3, the plasma source is ICP (Inductively Coupled Plasma), the specimen size is Ø30 mm x 1 mm (T), the gas is CF ₄ 60 sccm and O ₂ 10 sccm, the pressure is 13 mTorr, and the power (ICP / bias) is 2000 W / 300 W. And runtime is 12h.

	Psalter	Etch Amount Compared to Specimen	Etch amount per unit time (㎍ / h)
Example 5	Example 5	One	7.3
Comparative Example 1	CVD SiC	4.7	33.6
Comparative Example 2	RB SiC	4.9	33
Comparative Example 3	SSC	5.3	37.9
Comparative Example 4	Si	9.3	49.4

In Table 4, the plasma source is Capacitively Coupled Plasma (CCP), the specimen size is Ø30 mm × 1 mm (T), the gas is CF ₄ 25 sccm and O ₂ 25 sccm, the pressure is 13 mTorr, the power is 1000 W, and the runtime is 1 h. to be.

	Psalter	Etch Amount Compared to Specimen	Etch amount per unit time (㎍ / h)
Example 5	Example 5	One	8.3
Comparative Example 1	CVD SiC	0.93	7.8
Comparative Example 4	Si	2.07	12.6

4 is a scanning electron micrograph showing the surface of the specimen of Example 5 according to the plasma etching test, and FIGS. 5 to 7 are scanning electron micrographs showing the surfaces of the specimens of the comparative examples according to the plasma etching test.

In addition, the results according to the test for the generation of contaminated particles of the specimen of Example 5 are shown in Table 5 and Table 6, three cycles plasma processing was performed, one cycle is one hour, the rest time between cycles is 15 minutes.

The measuring equipment is a laser scattering ISPM, specimen size is Ø76 mm × 3 mm (circular), gas is CF ₄ 25sccm and O ₂ 25sccm, pressure is 160mTorr, RF power is 100W and temperature is 30 ~ 60 ℃.

Psalter	Contamination particle size
	1 ㎛ or more	0.45 to 1 μm	0.2 ~ 0.45㎛
Example 5	5	19	2059
Comparative Example 1 (CVD SiC)	6	22	22014

(Unit: number)

Psalter	cycle	Contamination particle size
		1 ㎛ or more	0.45 to 1 μm	0.2 ~ 0.45㎛
Example 5	One	2	2	1611
	2	0	3	136
	3	3	14	312
Comparative Example 1 (CVD SiC)	One	5	3	5917
	2	0	0	11202
	3	One	19	4895

(Unit: number)

As can be seen from the above, according to the silicon carbide ceramic material using the atmospheric pressure sintering method and the manufacturing method thereof according to the present invention, it is possible to provide a ceramic material that is dense, excellent in corrosion resistance and chemical resistance to plasma, and good thermal conductivity There is an advantage.

In addition, the present invention can be suitably employed in the jig of the semiconductor etching equipment, low thermal expansion rate, low resistance, excellent performance that can suppress the generation of arc in the plasma atmosphere, there is little risk of damage even during long-term use, It can be manufactured at low cost, and there is an advantage that can achieve economic advantages.

The embodiments and the accompanying drawings described herein are merely illustrative of some of the technical ideas included in the present invention. Therefore, since the embodiments disclosed herein are not intended to limit the technical spirit of the present invention, but to explain, it is obvious that the scope of the technical spirit of the present invention is not limited by these embodiments. Modifications and specific embodiments that can be easily inferred by those skilled in the art within the scope of the technical idea included in the specification and drawings of the present invention should be construed as being included in the scope of the present invention.

Claims (10)

1. A raw material preparation step of preparing a raw material powder by mixing a predetermined ratio of alpha silicon carbide (α-SiC) powder or beta silicon carbide (β-SiC) powder and a liquid sintering aid;

   Slurry step of slurrying the raw material powder prepared in the raw material preparation step;

   Dry granulation step of drying and granulating the raw material powder of the slurry in the slurry step;

   A molding step of molding the raw powder granulated in the dry granulation step into a predetermined form;

   A degreasing step of vacuum degreasing the molded body formed in the forming step; And

   Sintering step of sintering the molded body after the degreasing step

   Method for producing a low resistance silicon carbide ceramic material using an atmospheric pressure sintering method comprising a.
2. The method according to claim 1,

   In the raw material preparation step, the mixing ratio of the alpha silicon carbide (α-SiC) powder or beta silicon carbide (β-SiC) powder and the liquid sintering aid is alpha silicon carbide (α-SiC) powder or beta silicon carbide (β -SiC) 79.0% by weight to 99.0% by weight of powder, 1.0% by weight to 21.0% by weight of liquid sintering aid

   Method for manufacturing low resistance silicon carbide ceramic material using atmospheric pressure sintering method.
3. The method according to claim 2,

   The liquid sintering aid consists of a mixture of aluminum nitride (AlN) and yttria (Y ₂ O ₃ )

   Method for manufacturing low resistance silicon carbide ceramic material using atmospheric pressure sintering method.
4. The method according to claim 3,

   The mixing ratio of the aluminum nitride and yttria is 0.5 to 10.0 wt% of aluminum nitride and 0.5 to 20.5 wt% of yttria

   Method for manufacturing low resistance silicon carbide ceramic material using atmospheric pressure sintering method.
5. The method of claim 1, wherein the slurry step,

   200 parts by weight of an ethanol solvent is added to 100 parts by weight of the raw material prepared in the raw material preparation step, and 0.5 to 1.5 parts by weight of a dispersant and 1 to 3 parts by weight of a binder and zirconium oxide (ZrO ₂ Ball) are put together. Ball milling 24 hours

   Method for producing a low resistance silicon carbide ceramic material using an atmospheric pressure sintering method comprising a.
6. The method according to claim 1,

   The dry granulation step includes withdrawing the raw material slurried in the ball mill of the raw material preparation step to dry and granulate using a spray dryer equipment,

   The molding step includes molding at a pressure of 300 ~ 1,500kgf / cm ² using a molding mold

   Method for manufacturing low resistance silicon carbide ceramic material using atmospheric pressure sintering method.
7. The method according to claim 6,

   After the molding step, further comprises a secondary molding step for performing cold isostatic pressing (CIP: Cold Isostatic Press) at a pressure of 2,000kgf / cm ²

   Method for manufacturing low resistance silicon carbide ceramic material using atmospheric pressure sintering method.
8. The method according to claim 1,

   The degreasing step includes heating to 800 ° C. in a vacuum atmosphere to remove the binder contained in the molded article.

   The sintering step is a 1 ~ 8 at a temperature of 1,850 ~ 2,050 ℃ while flowing the nitrogen (N ₂ ) gas or argon (Ar) gas using a graphite work box (Graphite work box) in the degassing step Involving sintering time

   Method for manufacturing low resistance silicon carbide ceramic material using atmospheric pressure sintering method.
9. The low-resistance silicon carbide ceramic material according to any one of claims 1 to 8 has a volume resistivity value of 1.7 × 10 ⁻² to 6.5 × 10 ² Pa · Cm. Method of manufacturing the material.
10. A low resistance having a volume resistivity of 1.7 × 10 ⁻² to 6.5 × 10 ² Ω · Cm manufactured by the method of manufacturing a low resistance silicon carbide ceramic material using the atmospheric pressure sintering method according to any one of claims 1 to 8. Silicon carbide ceramic material.

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