KR20210092370A - Plasma resistant material with added fine particles and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a manufacturing method of plasma-resistant edge ring. Since it is possible to manufacture edge rings using a number of preformed specimens with uniformity secured through a prepress process, 30 to 60% of additional space in the mold can be secured compared to the case of using sample powder directly during hot-pressing sintering, making it possible to manufacture at least twice as many edge rings per one process as possible, prevent the introduction of impurities, and minimize a separate post-processing process such as wire cutting after sintering. In addition, by performing a cold isostatic pressure treatment on the preformed specimen by the prepress process, the foreign material of the specimen is removed, and by minimizing the density deviation of the specimen, it is possible to effectively prevent distortion of the specimen during hot-press sintering. Accordingly, there is an effect that the sintered density of the edge ring manufactured through the hot pressing sintering process corresponds to 95 to 99.9% of the theoretical value. The present invention relates to performing semi-sintering and impregnating the semi-sintered specimen with an additive to increase the relative density of the semi-sintered specimen, thereby lowering the heat treatment age during re-sintering and increasing the sintering density. The object of the present invention is to provide a plasma resistant material and a manufacturing method to which fine particles are added in order to improve the uniformity of a ceramic composite used in semiconductor manufacturing.

Description

Plasma-resistant material with added particulates and a manufacturing method therefor {PLASMA RESISTANT MATERIAL WITH ADDED FINE PARTICLES AND MANUFACTURING METHOD THEREOF}

The present invention relates to a plasma resistant material composed of a ceramic resin composite and a method for manufacturing the same.

The semiconductor wafer manufacturing process is continuously developing through the reversal of technology and the miniaturization of line width and increase in the number of stacks. Meanwhile, as the plasma environment in the semiconductor manufacturing chamber becomes increasingly harsh, the ceramic component for semiconductor manufacturing used in the chamber needs to have high plasma resistance.

For example, a plasma apparatus (chamber) in which plasma etching is performed includes an electrostatic chuck including an upper electrode and an electrode at a lower portion, and a covering assembly surrounding the electrostatic chuck to protect the electrostatic chuck from plasma generated in the plasma processing chamber, , a substrate such as a semiconductor wafer or a glass substrate is supported on the upper surface of the electrostatic chuck. With this configuration, as power is applied between the upper electrode and the lower electrostatic chuck, plasma (P) is generated in the plasma process chamber by the electric field effect, and the ions are incident in the direction toward the electrostatic chuck, and the chemical reaction of plasma ions and Etching is performed on the substrate using kinetic energy.

Meanwhile, the covering assembly surrounding the electrostatic chuck may have a configuration in which a coupling groove is formed on a lower surface of an edge ring and an electrode ring is coupled thereto, and the edge ring surrounds a side surface of a substrate supported on an upper surface of the electrostatic chuck. is a ceramic component for semiconductor manufacturing manufactured in a three-dimensional shape of a standard and environment capable of maintaining the same height as a substrate supported by an electrostatic chuck.

On the other hand, the existing edge ring was manufactured and used with single crystal silicon (Silicon) or quartz (Quartz), but this composition is excessively etched under severe plasma conditions, so maintenance or replacement with new parts is required after a short use there was

Therefore, today, the edge ring is manufactured using a sintered body using a non-oxide-based structural material such as silicon carbide, boron carbide, and silicon nitride. In particular, the hot press sintering method is a method of manufacturing a sintered body by pressing a ceramic material in a specific atmosphere. As one of the methods with excellent characteristics of the sintered body, it is being applied to the manufacturing process of edge rings, which are ceramic parts for semiconductor manufacturing.

In general, the above-mentioned sintered body is molded by a hot press method. Specifically, when performing the hot press method, particles having a size of sub-micro level are used, and after a sample having particles of this size is filled in a carbon mold, it is molded into a sintered body by high temperature and high pressure. will be.

However, according to the above method, since a difference in pressure gradient is unavoidable, there is a problem that non-uniformity may occur in the microstructure of the specimen. When the specimen is non-uniformly formed, not only the physical strength of the sintered body is reduced, but also electrical properties of the sintered body are non-uniform for each microstructure. Furthermore, there may be a problem in that the mold used to fill the specimen is broken.

It is an object of the present invention to provide a resistance control ceramic composite of a plasma resistant material and a method for manufacturing the same.

Another object of the present invention is to provide a plasma resistant material to which fine particles are added, and a method for manufacturing the same, in order to improve the uniformity of a ceramic composite used in semiconductor manufacturing.

In order to solve this problem, in the present invention, by performing semi-sintering and impregnating the semi-sintered specimen with the additive, the additive is filled between the semi-sintered microstructures to increase the relative density of the semi-sintered specimen. It is to lower the heat treatment age and increase the sintering density during re-sintering.

According to the present invention, the uniformity of the sintered body is secured, and there is an advantage in that the strength is improved.

In addition, since the sintered compact according to the present invention is processed in a low relative density through the semi-sintering process, there is an advantage in that the convenience of processing is improved.

1 is a schematic diagram briefly showing a prepress process according to an embodiment of the present invention.
2 schematically shows a shape in which a plurality of preformed specimens are stacked through a prepress process according to an embodiment of the present invention.
3 schematically shows a mold shape of a multilayer laminate structure in which hot pressing sintering is performed according to an embodiment of the present invention.
4 schematically shows a mold shape of a multilayer laminate structure in which hot pressing sintering is performed according to another embodiment of the present invention.
5 is a cross-sectional view showing that a carbon sheet is provided between the laminated specimens during hot pressing sintering according to another embodiment of the present invention.
6 is a flowchart illustrating a method of manufacturing a ceramic composite according to an embodiment of the present invention.

Since the invention may have various modifications and various forms, specific embodiments will be illustrated and described in detail below. However, this is not intended to limit the invention to the specific disclosed form, and it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the invention.

Hereinafter, a plasma-resistant edge ring manufacturing method according to a specific embodiment of the present invention and a plasma-resistant edge ring manufactured thereby will be described.

First, as described above, today's edge rings are manufactured using a sintered body obtained by hot-pressure sintering of non-oxide-based structural materials such as silicon carbide, boron carbide, and silicon nitride. There is a problem in that the density deviation of In addition, according to the above method, the period per unit operation is long and the specific surface area is large, so the number of sintered bodies that can be produced during one process is small, so the process cost is very high. There is a problem in that the working time is lengthened by repetitive processes such as raising the carbon sheet, raising the spacer for uniform pressurization, and then raising the carbon sheet again. In addition, according to the above method, there may be a problem that foreign substances are introduced during the sample loading procedure.

The present inventors, paying attention to the above problems, in the case of hot pressing and sintering of a preformed specimen through prepress and cold isostatic pressing (CIP) processing, a plurality of Since edge rings can be manufactured using pre-formed specimens, 30 to 60% of additional space can be secured in the mold compared to using sample powder directly during hot-pressing sintering, so edge rings at least 3 times more per one process can be manufactured, and the introduction of impurities can be prevented.

On the other hand, for CIP processing, a CIP mold is required, which has a problem of reducing the convenience of operation as the size of the specimen increases.

Therefore, in the present invention, before the specimen is completely sintered, fine particles composed of the same composition as the specimen may be impregnated, and the CIP treatment may be performed after the impregnation is performed. Accordingly, it is possible to secure the uniformity improvement effect by the CIP treatment and the convenience of operation.

Plasma resistant edge ring manufacturing method

Specifically, the plasma-resistant edge ring manufacturing method according to an embodiment of the present invention is a) one selected from the group _{consisting of silicon carbide (SiC), boron carbide (B 4} C) and silicon nitride (Si ₃ N _{4 )} preparing a granulated powder by pre-treating the above sample; b) pre-forming the granulated powder through a prepress (PrePress) to prepare a ceramic specimen; c) removing the density deviation of the specimen by cold isostatic pressing (CIP) treatment of the ceramic specimen; and d) laminating the specimen in a mold and hot pressing sintering; may include.

First, at least one sample selected from the group consisting of silicon carbide (SiC), boron carbide (B ₄ C) and silicon nitride (Si ₃ N ₄ ) is pretreated to prepare a granulated powder (step a).

Silicon carbide (SiC), boron carbide (B ₄ C) and silicon nitride (Si ₃ N ₄ ) are non-oxide-based structural materials, with mechanical properties such as high strength, high hardness and abrasion resistance as well as oxidation resistance, corrosion resistance, and low thermal conductivity. And it is a main material of ceramics having thermal properties such as high thermal shock resistance and high temperature strength due to the coefficient of thermal expansion. In particular, the non-oxide-based structural material has a strong covalent bond due to the characteristics of the material, and the energy of the grain boundary is high, and the diffusion rate of the grain boundary is low, so that there is a considerable difficulty in molding through sintering.

Meanwhile, according to an embodiment of the present invention, one or more samples selected from the group consisting of silicon carbide (SiC), boron carbide (B ₄ C) and silicon nitride (Si3N _{4 ) as the non-oxide-based structural material are pre-treated,} It is prepared as a granulated powder. In particular, the preparation of the sample as a granulated powder is for the granulation form to increase the flowability of the powder form, and thus for a smooth process progress during the prepress process, and an antifoaming agent to the sample to prepare a granulated powder , a release agent and a binder may be added to prepare a granulated powder having a particle diameter of about 10 to 100 μm.

Next, the granulated powder is preformed through a prepress (PrePress) to prepare a ceramic specimen (step b).

The prepress of the above step is a process performed to manufacture a plurality of preformed specimens with secured uniformity. In the case of hot-pressing sintering, which will be described later, using the preformed specimen through the above process, a conventional sample powder is used. Compared to the direct use method, it is possible to secure an additional space of 30 to 60% in the mold, making it possible to manufacture at least two or more edge rings per one process, effectively preventing the ingress of impurities during hot-pressing sintering processing, and also There is an effect that it is possible to minimize a separate post-processing process such as wire cutting after sintering.

On the other hand, the prepress of this step may be performed by first preparing a mold for prepress, filling the mold with the granulated powder of the sample prepared in step a, leveling, and then uniaxially pressing (Fig. see 1).

Specifically, the above process fills the mold with granulated powder and then fills the sample uniformly through flattening of the top surface, but fills only the own weight of the powder without partial pressure or relief, and then pushes out the unnecessary upper part. can be done in this way.

Next, a preformed specimen is prepared by uniaxially pressing against the filled granulated powder, and the pressing condition may be performed by pressing within the range ^{of 50 to 150 kg/cm 2 .}

Next, the ceramic specimen is subjected to cold isostatic pressing (CIP) to remove the density deviation of the specimen (step c).

The cold isostatic pressing removes foreign substances from the specimen with respect to the preformed specimen obtained through step b, and minimizes the density deviation of the specimen to effectively prevent distortion of the specimen during hot pressing sintering, which will be described later. it could be

Specifically, the cold isostatic pressing method of this step may be performed by pressurizing a liquid at 1,000 to 2,000 bar as a pressure medium for 1 to 10 minutes, specifically for 5 minutes, in order to equalize the density of the specimen, and the above process Through this, the preformed specimen is subjected to uniform pressure in all directions, so that the density deviation between products is minimized.

Meanwhile, foreign matter on the preformed specimen is removed through the above step, and a preformed specimen having a uniform shape can be obtained. In addition, the plurality of specimens obtained through the above step can be easily separated by inserting a carbon sheet member between the specimen and the specimen using a carbon sheet member to prevent bonding between the specimens, and as the laminated form is described later. It may also be put into a mold for pressure sintering (see FIG. 2).

Next, the specimen obtained in step c is laminated in a mold and sintered under hot pressure (step d).

On the other hand, as a sintering molding method for obtaining a dense sintered body reaching theoretical density mainly using ceramics, etc., there are atmospheric sintering method, reaction sintering method, recrystallization method, oxide bonding method, hot pressing sintering method, and the like.

In the present invention, for the production of a sintered body, a hot pressure sintering method can be used to achieve densification close to the theoretical density at a temperature lower than atmospheric sintering without a sintering aid or with a minimum amount of non-oxide ceramics, which is difficult to sinter, can be used.

Specifically, a specimen obtained in the above step c as the temperature and 50kgf / cm ² to 220kgf / cm ² pressure of 1900 to 2100 ℃ range charged, and in the mold provided in the furnace (furnace), and more particularly 2100 ℃ temperature And 186 kgf / cm ² It is possible to form a sintered compact by uniaxial pressure under pressure conditions.

On the other hand, the mold used in the above step is a configuration for manufacturing the sintered body, for example, a graphite material may be used, and a plurality of specimens may be sintered at the same time in a mold of a multi-layered laminate structure.

More specifically, the mold according to an embodiment of the present invention includes a mold die provided on the outermost outer circumferential surface, an outer sleeve provided inside the mold die, and an inner spaced apart from the outer sleeve inside the outer sleeve by a predetermined distance. One or more mold units including a sleeve, a core disposed in the inner sleeve, an upper punch formed at an upper end of the space spaced apart between the outer sleeve and the inner sleeve, and a lower punch formed at a lower end of the spaced space. ) and may include a base formed on the upper and lower portions of the one or more mold units, respectively.

Specifically, as shown in FIG. 3 , in the mold of the multilayer stack structure according to an embodiment of the present invention, two mold units are provided between an upper base and a lower base, and a coupling base is provided between the two mold units. is provided, and each mold unit is disposed with the coupling base as a boundary. On the other hand, the mold according to another embodiment of the present invention may include two or more mold units (units), in this case, the mold units may be stacked on the basis of the coupling base as described above and disposed as a boundary, The coupling base may be provided between each mold unit.

On the other hand, the sleeve has a trapezoidal cross-sectional shape, is provided to facilitate demolding of the sintered body, may have a divided structure, prevent direct contact between the die and the sintered body, and is easy to separate and replaceable. . On the other hand, the core is provided to fix the inner sleeve, and has a feature of reducing defects resulting from the difference in thermal expansion due to cooling of the sintered body, and the core according to an embodiment of the present invention may have a four- or six-division structure. In this case, since the inner core is easily demolded, it is possible to effectively prevent damage to the sintered body during demolding.

On the other hand, the punch serves to form the sintered body in a desired shape by adjusting the gap between the upper punch and the lower punch according to a desired shape when manufacturing the sintered body.

On the other hand, a hole may be formed inside the core, and when the hole is formed inside the core, shrinkage stress during cooling after sintering the sintered body is reduced to minimize defects in the sintered body.

On the other hand, the component of the mold may additionally include a carbon sheet (not shown), which is provided to facilitate demolding, prevent contamination, and match thermal expansion, specifically 0.5 mm to 5 mm Carbon sheets in a range of thicknesses may be used.

Plasma resistant edge ring

On the other hand, the sintering density of the plasma-resistant edge ring manufactured according to the plasma-resistant edge ring manufacturing method according to an embodiment of the present invention may be 95 to 99.9% of the theoretical value, and by this characteristic, the plasma resistance and corrosion resistance are very excellent.

In Figure 6, the ceramic composite manufacturing method proposed by the present invention is shown.

Referring to FIG. 6 , an embodiment of the method for manufacturing a ceramic composite according to the present invention includes the steps of preparing granulated powder (S601), preparing a ceramic specimen (S602), and laminating the specimen in a mold ( S603), a semi-sintering step (S604), an impregnation step (S605), may be composed of a re-sintering step (S606).

Specifically, in the step of preparing the granulated powder (S601), one or more samples selected from the group _{consisting of silicon carbide (SiC), boron carbide (B 4} C) and silicon nitride (Si ₃ N _{4 ) can be pre-treated.} there is.

When the granulated powder is prepared, the step (S602) of pre-forming the granulated powder through a prepress to prepare a ceramic specimen may be performed. The ceramic specimen prepared in this way may be laminated in a mold (S603).

In the method for manufacturing a ceramic composite according to the present invention, the step of semi-sintering by performing firing on at least a portion of the laminated specimen (S604) may be performed.

That is, the specimen may be sintered such that 50% to 90% of the specimen is sintered, rather than performing complete sintering after the specimen is laminated.

When hot pressing is performed in the semi-sintering step, a problem in that the porous body is not sufficiently formed and the sintering density of only the surface of the semi-sintered object is increased may occur. Therefore, in order to increase the success rate of the impregnation after the semi-sintering step, it is appropriate to perform firing.

In one example, the semi-sintering step may be performed by firing the specimen such that 50% to 90% of the specimen is sintered.

Meanwhile, in a state in which at least a portion of the specimen is sintered, the step of impregnating the specimen with a predetermined additive ( S605 ) may be performed.

Finally, the step (S606) of re-sintering by hot pressing the specimen impregnated with the additive may be performed. At this time, the re-sintering is preferably performed at a temperature lower than the temperature at which complete sintering is performed.

In one example, the impregnated additive may be made of the same material as the specimen. More preferably, the additive may be composed of fine particles of a semi-sintered specimen.

In another example, the impregnated additive may include at least one of an oxide for a resistor, a boron compound for a conductor, and a conductive metal. In particular, the additive is at least one of silicon carbide (SiC), titanium diboride (TiB ₂ ), ceramic oxide (ZrO ₂ ), yttrium (Y ₂ O ₃ ), titanium (Ti), iron (Fe) and aluminum (Al). may contain one.

In another embodiment, the pre-sintering step may further include removing a predetermined boron oxide from the surface of the sintered body.

According to the plasma-resistant edge ring manufacturing method of the present invention described above, it is possible to manufacture the edge ring using a plurality of preformed specimens with uniformity secured through the prepress process, so that the sample powder during hot pressing sintering processing It is possible to secure an additional space of 30 to 60% in the mold compared to the case of directly using There is an effect that separate post-processing processes such as cutting are minimized.

In addition, according to the plasma-resistant edge ring manufacturing method of the present invention, by performing a cold isostatic pressing treatment on a specimen pre-formed by a prepress process, foreign matter in the specimen is removed, and the density deviation of the specimen is minimized to minimize the hot It is possible to effectively prevent distortion of the specimen during the pressure sintering processing, and accordingly, the sintering density of the edge ring manufactured through the hot pressing sintering processing corresponds to 95 to 99.9% of the theoretical value, thereby minimizing the deviation.

Hereinafter, the action and effect of the invention will be described in more detail through specific examples of the invention. However, this is presented as an example of the invention and the scope of the invention is not limited in any sense by this.

Example 1

Prepare 1000 g of boron carbide powder, mix 2 g of CONTRASPUM as an antifoaming agent, 10 g of ethylene glycol as a mold release agent, and 30 g of polyvinyl alcohol as a binder. got

Next, the granulated boron carbide powder was filled in the prepared mold for prepress and leveling was performed, and then a boron carbide specimen was prepared by uniaxially pressing at 80 kg/cm 2 , and it was prepared by laminating it in three layers.

Next, the stacked boron carbide specimen was pressurized for 5 minutes under 1500 bar conditions using a CIP apparatus to perform a cold isostatic pressing process.

Next, the specimen obtained through the above step was charged into a mold for hot pressing, and uniaxially pressed at a temperature of 2100° C. and a pressure of 186 kgf/cm 2 to form a sintered body. The sintered body may be used as an edge ring product constituting the covering assembly in the plasma apparatus without a separate post-processing process.

Comparative Example 1

A sintered body for a plasma-resistant edge ring was prepared in the same manner as in Example 1,

After filling the inside of the mold with the granulated powder prepared in Example 1, it was charged into a mold for hot pressing, and uniaxially pressed at 2100° C. and 186 kgf/cm 2 pressure to form a sintered body.

Example 1 Comparative Example 1 thickness deviation 0.1 0.5 Density deviation 0.2% 0.5%

a0: granulated sample powder m: mold for prepress
a: preformed specimen r: leveling means
b: carbon sheet
110: mold die 120: outer sleeve
130: inner sleeve 140: core
150: upper punch 160: lower punch
20: combined base 30: upper base
40: lower base

Claims (7)

a) preparing a granulated powder by pre-treating at least one sample selected from the group consisting of silicon carbide (SiC), boron carbide (B ₄ C) and silicon nitride (Si ₃ N _{4 );}
b) pre-forming the granulated powder through a prepress (PrePress) to prepare a ceramic specimen;
c) laminating the specimen in a mold;
d) performing sintering on at least a portion of the laminated specimens to semi-sinter;
e) in a state in which at least a portion of the specimen is sintered, impregnating the specimen with a predetermined additive; and
f) re-sintering by hot pressing the specimen impregnated with the additive;
The method of claim 1,
The additive is
A method for manufacturing a ceramic composite, characterized in that it is made of the same material as the specimen.
3. The method of claim 2,
The additive is
A method of manufacturing a ceramic composite comprising at least one of an oxide for a resistor, a boron compound for a conductor, and a conductive metal.
4. The method of claim 3,
The additive is
Silicon carbide (SiC), titanium diboride (TiB ₂ ), ceramic oxide (ZrO ₂ ), yttrium (Y ₂ O ₃ ), titanium (Ti), iron (Fe) and aluminum (Al) containing at least one A method for manufacturing a ceramic composite, characterized in that
The method of claim 1,
The semi-sintering of step d is a ceramic composite manufacturing method, characterized in that it is performed by firing the specimen so that 50% to 90% of the specimen is sintered.
The method of claim 1,
When the semi-sintering of step d is performed, the method of claim 1 , further comprising: removing a predetermined boron oxide from the surface of the sintered body.
The method of claim 1,
The re-sintering of step f is a ceramic composite manufacturing method, characterized in that it is performed at a temperature lower than the temperature at which complete sintering is performed.

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