JP4570195B2 - BORON CARBIDE BONDED BODY, ITS MANUFACTURING METHOD, AND PLASMA RESISTANT MEMBER - Google Patents

Description

【００６０】
本発明の試料Ｎｏ．３〜７および９〜２８は、接合強度が２００ＭＰａ以上であった。
【００６１】
一方、周期律表第４ａおよび５ａ族元素から選ばれた少なくとも１種の化合物を含まない試料Ｎｏ．１、炭化硼素粉末の含有量が９９．５重量％と本発明の範囲外の試料Ｎｏ．２、炭化硼素粉末の含有量が８０重量％に満たない本発明の範囲の試料Ｎｏ．８は、接合強度が１８０ＭＰａ以下と２００ＭＰａに達しなかった。
【００６２】
【発明の効果】
本発明では、窒化硼素質焼結体の間に特定の組成からなる接合部を設け、特定の熱処理により、原料および加工コストを低減し、接合強度を高くすることができる。
【図面の簡単な説明】
【図１】本発明のエッチング装置の概略断面図である。
【符号の説明】
１・・・エッチング装置
２・・・チャンバー壁
３・・・シャワーヘッド
４・・・高周波コイル
５・・・ウエハ
６・・・固定治具
７・・・フォーカスリング[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a boron carbide joined body that is used in a jig for semiconductor manufacturing equipment and the like and has high corrosion resistance against fluorine-based and chlorine-based corrosive gas atmospheres, particularly fluorine-based and chlorine-based plasmas, particularly halogen plasma. Boron carbide joined body suitable for precision processing products such as a focus ring, a clamp ring, a member for a plasma processing apparatus such as a bell jar and a dome, and a jig such as a support for supporting an object to be processed, and a method for manufacturing the same And a plasma-resistant member suitably used in a material manufacturing process such as a semiconductor or liquid crystal device manufacturing process, a micromachine manufacturing process, an electronic circuit manufacturing process, or a thin film manufacturing process, particularly a manufacturing process involving plasma processing. The present invention relates to a plasma apparatus.
[0002]
[Prior art]
Currently, the plasma apparatus is a process for manufacturing devices such as semiconductors and liquid crystals, a manufacturing process for micromachines formed using etching, a manufacturing process for electronic circuits for forming wiring boards, a thin film manufacturing process such as sputtering and plasma CVD, and the like. It is used in a wide range of manufacturing processes such as other processes involving etching.
[0003]
A plasma device is a device for ionizing a part of a specific gas to form a gas composed of electrons, ions, and neutral particles, and includes a vacuum vessel, a gas introduction device, a plasma generation device, It is a device equipped with a fixture that holds the processed material. Specifically, it is a nuclear fusion device, a thin film forming device such as plasma CVD, sputtering or ion plating, RIE (reactive ion etching) or high-density ion etching. Examples include etchers such as devices.
[0004]
A plasma generator is an apparatus for ionizing a gas by generating an electromagnetic field by direct current, alternating current, high frequency, etc. Especially, plasma is formed by using a high frequency of 0.8 to 13.56 MHz and a microwave of 2.45 GHz. A power source and an electrode.
[0005]
In particular, in an etching apparatus used in a plasma semiconductor manufacturing process or a manufacturing process involving other etching processes, plasma is generated by applying a high frequency to a flat electrode or a coiled induction electrode as a gas in the apparatus, or microwaves are generated. Is introduced into a vacuum vessel to generate plasma, and the surface of the object to be processed is etched in a corrosive gas plasma atmosphere.
[0006]
For this reason, in these plasma apparatuses, corrosion of members inside the apparatus is particularly severe, which has affected yield, product cost, and product reliability. In particular, plasma processes used for dry process and plasma coating used in the formation of highly integrated circuits such as semiconductor elements use halogen-based corrosive gases such as fluorine and chlorine, and are highly corrosive to plasma. Members that come into contact with these corrosive gases are required to have as much corrosion resistance as possible and to contain as little impurities as possible that contaminate untreated materials and cause particles.
[0007]
That is, conventionally, members that come into contact with plasma have generally started to use materials such as glass and quartz whose main component is SiO ₂ , metals such as stainless steel and monel, and alumina as a ceramic material. In particular, alumina is starting to be widely used in semiconductor manufacturing processes as a corrosion-resistant member because a high-purity sintered body can be produced at a relatively low cost and has excellent corrosion resistance.
[0008]
However, in the members using quartz glass or the like that have been used conventionally, the consumption in the plasma is severe, especially when contacting with fluorine or chlorine plasma, the contact surface is etched, and the surface properties change to affect the etching conditions. Etc. had occurred. Further, even a member using a metal such as stainless steel has insufficient corrosion resistance, so that corrosion causes a defective product particularly in semiconductor manufacturing.
[0009]
In addition, although the sintered body of alumina and AlN is superior in corrosion resistance to fluorine-based gas as compared with the above materials, corrosion gradually proceeds when contacting with plasma at high temperature, and crystal particles are formed from the surface of the sintered body. This causes a problem that the degranulation occurs and causes the generation of particles.
[0010]
The generation of such particles is due to device characteristics due to ion bombardment, breakage of metal wiring, pattern defects, etc., due to ion bombardment and extremely fine particles generated by reaction in the gas phase as semiconductors become more highly integrated and processes become cleaner. There is a risk of problems such as deterioration of the product and a decrease in yield.
[0011]
In recent years, therefore, it has been proposed to use boron carbide, which is excellent in corrosion resistance against halogen-based corrosive gas, particularly chlorine-based gas plasma, and is less likely to generate particles, as an electrode for a dry etching apparatus (for example, Japanese Patent Laid-Open No. Hei 1). -59818).
[0012]
By the way, boron carbide is known as a hard-to-sinter body, and if there are voids, the corrosion rate around the voids due to plasma increases, so hot pressing by pressing in a high-temperature inert atmosphere, that is, in an argon stream at 2100 ° C. or higher. It was necessary to obtain a dense body by the method. For example, Japanese Examined Patent Publication No. 58-30263 discloses a boron carbide firing having a density of 90% or more of the theoretical density in which 0.5 to 10% by weight of free carbon is mixed with powdered boron carbide having a particle size distribution of 1 μm or less. Conjunctions are described.
[0013]
[Problems to be solved by the invention]
However, since boron carbide sintered bodies are difficult to sinter and are generally formed by a hot press method, it is necessary to first produce a simple-shaped sintered body and then cut and process it to obtain the desired shape. was there. However, boron carbide has the second highest hardness after diamond, requires an enormous amount of diamond tools compared to other ceramics, and requires a long time for processing, so there is a problem that the processing cost of boron carbide is very high. It was a big obstacle to practical use.
[0014]
Further, the boron carbide disclosed in Japanese Patent Publication No. 58-30263 is very expensive as a boron carbide raw material itself. For example, when a simple shaped sintered body is processed to obtain a desired shape, it is removed as processed powder. The amount of boron carbide to be used increases, the raw material cost to use increases, and the product cost rises. Especially when the product has a complicated shape, the raw material cost and the processing cost increase so that the product price becomes high and is difficult to adopt. There was a problem.
[0015]
Furthermore, even when trying to obtain the target shape while reducing the wasteful raw material by joining the members made of boron carbide sintered body and reducing the processing cost, the joining method has not been established. There was a problem that a sufficient bonding strength could not be obtained.
[0016]
Accordingly, an object of the present invention is to provide a boron carbide joined body having a strength that can withstand practical use, a manufacturing method thereof, and a plasma apparatus.
[0017]
[Means for Solving the Problems]
The present invention is based on the knowledge that the bonding strength can be increased by specifying the composition of the bonding portion and the bonding method, and as a result, the cost of the product made of the boron carbide sintered body can be reduced.
[0018]
That is, the present invention relates to a boron carbide joined body in which two members made of a boron carbide sintered body are integrated through a joint portion, wherein the joint portion is 80 to 99 wt% boron carbide, It comprises 1 to 20% by weight of at least one oxide or boride selected from Group 4a and 5a elements of the Periodic Table.
[0019]
According to the present invention, the boron carbide, to form the joint by the at least one acid halide or borides selected from the periodic table 4a and 5a group element of 1 to 20 wt%, the bonding portion Sintering is promoted and densification progresses, and a bonded portion with high adhesion strength can be formed. As a result, strength reduction can be prevented, and processing costs can be reduced.
[0020]
In addition, it is preferable that the thickness of a junction part is 100 micrometers or less, and it is preferable that the average particle diameter of the boron carbide of a junction part is 5 micrometers or less. The thickness of the joint and the average particle diameter of boron carbide in the joint have the effect of increasing the joint strength, and the joint strength can be further increased by setting the above range.
[0021]
In addition, the method for producing a boron carbide joined body of the present invention comprises 80 to 99% by weight of boron carbide powder and at least one oxide powder or boride powder (hereinafter referred to as the group 4a and 5a elements of the periodic table). The slurry prepared by adding an organic binder to a mixture having a ratio of 1 to 20% by weight may be at least one of the joint surfaces of two members made of a boron carbide sintered body. After being applied to the surface, the member bonding surfaces are brought into contact with each other and heat-treated at a temperature of 1900 ° C. or higher in an inert atmosphere, whereby a boron carbide bonded body having high bonding strength at low cost can be obtained. It can be manufactured and can handle complex shapes.
[0022]
Moreover, it is preferable that the average particle diameter of boron carbide powder is 5 μm or less, and the average particle diameter of the compound powder composed of Group 4a and 5a elements of the periodic table is 5 μm or less. As a result, a dense joint is obtained, and a high joint strength is obtained.
[0023]
Therefore, according to the present invention, it is possible to provide a boron carbide bonded body having a bonding strength for practical use and a method for manufacturing the same, with reduced product costs.
[0024]
The plasma-resistant member of the present invention is characterized by using the boron carbide joined body of the present invention. Thereby, while extending the lifetime of a member, a reliable plasma-resistant member can be provided.
[0025]
Furthermore, the plasma apparatus of the present invention is, for example, a plasma apparatus including a vacuum vessel, a gas introduction device, a plasma generation device, and a fixing jig for holding an object to be processed. As a member to be used, the boron carbide joined body of the present invention is used. Thereby, the plasma apparatus which can manufacture a product with a long lifetime of a member, high productivity, and high reliability is realizable.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
The boron carbide joined body of the present invention is a boron carbide joined body in which two members made of a boron carbide sintered body are integrated with each other through a joint, and the joint is made of boron carbide and groups 4a and 5a of the periodic table. It is composed of at least one oxide or boride (hereinafter sometimes referred to as a compound ) selected from elements. By forming a joint made of at least one compound selected from Group 4a and 5a elements of the Periodic Table that acts as a boron carbide sintering aid, sintering of the joint interface is promoted and strength reduction is achieved. Can be prevented.
[0027]
That is, the bonding part composition of the boron carbide bonded body of the present invention is 80 to 99% by weight of boron carbide and 1 to 20% by weight of at least one compound selected from Group 4a and 5a elements of the periodic table. It is necessary. In particular, boron carbide 85 to 95 wt%, more preferably 88 to 92 wt%, at least one compound selected from the periodic table 4a and 5a group element is 5-15 wt%, more 8 ˜12% by weight is preferred.
[0028]
When boron carbide is less than 80% by weight or when at least one compound selected from Group 4a and 5a elements of the periodic table exceeds 20% by weight, boron carbide causes grain growth and the strength decreases. Further, if at least one compound selected from Group 4a and 5a elements of the periodic table is less than 1% by weight or boron carbide exceeds 99% by weight, densification of the joint cannot be achieved and joint strength is reduced. To do.
[0029]
Therefore, by making the content of at least one compound selected from Group 4a and 5a elements of the Periodic Table within the above range, densification of the joint is promoted, while grain growth. Therefore, sufficient bonding strength can be obtained.
[0030]
Further, the thickness of the joint is preferably 100 μm or less, particularly 50 μm or less, and more preferably 20 μm or less. When the thickness of the joint portion is reduced, the existence probability of voids and other defects that become a fracture source is reduced, and as a result, high joint strength tends to be obtained.
[0031]
Furthermore, the average particle diameter of boron carbide at the joint is preferably 5 μm or less, more preferably 3 μm or less. Since the surface energy of the particles increases due to the small particle diameter and is easily diffused, the bonded portion is likely to be dense and high bonding strength can be obtained.
[0032]
The at least one compound selected from the periodic table 4a and 5a group element, Ti, Zr, Hf, V, Nb, Ta and the like, is not preferable particularly Ti and Nb.
[0033]
Members made of boron carbide sintered body to be used for bonding, that those sintering sintering aids made of silicon carbide or carbon in the boron carbide powder was added in an amount of 1-5% by weight suitably used it can. Firing at that time may be performed at a temperature of 2000 ° C. or higher by an atmospheric pressure method in an inert gas, hot pressing, or hot isostatic pressing (HIP), but in order to obtain a dense body, hot pressing is particularly preferable. . Here, the relative density of the boron carbide sintered body used as the joining member is preferably 98% or more, particularly 99% or more, because of excellent properties such as corrosion resistance, wear resistance, and strength.
[0034]
The joint portion contains boron carbide and at least one compound selected from Group 4a and 5a elements of the periodic table. However, even if an element such as aluminum or iron is mixed as an impurity, the joint strength is affected. If you don't give it, there is no problem. In general, these impurities are contained in the raw material of boron carbide by several hundred ppm. However, even if these elements remain with respect to the bonding strength, it does not hinder the achievement of the object of the present invention.
[0035]
In addition, a bonding strength of 200 MPa is a practical standard. When the pressure is less than 200 MPa, there is a tendency for jigs and apparatus constituent members to be unusable due to insufficient strength or have a short life. Furthermore, 250 MPa or more is preferable in consideration of ease of handling, life, or safety.
[0036]
Further, the method for producing a boron carbide joined body of the present invention comprises 80 to 99% by weight of boron carbide powder and at least one oxide powder or boride powder 1 to 1 selected from Group 4a and 5a elements of the periodic table. After applying a slurry prepared by adding an organic binder to a mixture having a proportion of 20% by weight on at least one surface of the joint surfaces of two members made of a boron carbide sintered body , the member joint surface It is characterized in that they are brought into contact with each other and heat-treated at a temperature of 1900 ° C. or higher in an inert atmosphere, whereby a high-strength boron carbide bonded body can be produced at a low cost and a dense bonded portion The strength can be increased.
[0037]
In this case, the average particle diameter of the boron carbide powder is preferably 5 μm or less, particularly preferably 3 μm or less. A powder having an average particle diameter in this range has good sinterability, and a dense body can be easily obtained at a low temperature in a short time.
[0038]
To this powder is added a compound powder composed of one or more elements of Group 4a or 5a of the periodic table having an average particle diameter of 5 μm or less, particularly 2 m or less. By reducing the average particle size, the sinterability is promoted and a dense body can be easily obtained. Moreover, it is important that the addition amount is 1 to 20% by weight, and 5 to 15% by weight is particularly preferable. By setting the addition amount in this way, the bonding strength can be increased.
[0039]
An organic binder such as an acrylic resin is added in an amount of 10 to 60% by weight, preferably 20 to 40% by weight, based on 100 parts by weight of the powder mixture. If it is less than 10% by weight, it does not become a paste and it is difficult to apply uniformly, and if it exceeds 60% by weight, the packing density of the powder is low, it becomes difficult to sinter, and the bonding strength decreases. It is because it ends.
[0040]
Furthermore, if necessary, a plasticizer or the like is added, mixed well, and slurried. After applying this slurry to at least one surface of the joint surfaces of the two members, the member joint surfaces are brought into contact with each other. At this time, as a method of applying, a method of applying with a brush, a dipping method in which a member is put in the slurry and the slurry is adhered to the bonding surface, or a printing method can be used.
[0041]
Thereafter, in an inert atmosphere such as argon gas, when the compound powder to be added is an oxide powder , the temperature is 1900 ° C. or more, preferably 1950 ° C. or more, and in the case of a boride powder , the temperature is 2100 ° C. or more, preferably 2150 ° C. or more. And heat-treated for 1 to 10 hours. At this time, if the heat treatment temperature is low, the joint portion is insufficiently densified, which tends to cause a decrease in strength.
[0042]
At the time of sintering, it is preferable to apply pressure to the joint surface from the member side. If it is a simple shape, it can be pressurized using a hot press apparatus. Moreover, you may place a heavy article on a member as a heavy stone. Furthermore, after firing and clogging the pores, the remaining closed pores can be reduced by pressurization by HIP treatment or the like in an inert gas atmosphere such as argon at 100 atm or higher.
[0043]
Next, the plasma apparatus will be described based on, for example, a schematic layout diagram of the plasma apparatus in FIG. The plasma apparatus of FIG. 1 is an etching apparatus 1 used in a manufacturing process of a semiconductor, liquid crystal, or the like, and introduces a gas including a vacuum vessel having a chamber wall 2 as a constituent element, a shower head 3 and piping connected thereto. From a device, a plasma generator including a high-frequency coil 4 and a high-frequency transmitter electrically connected thereto, a fixing jig 6 that fixes the wafer 5 and also serves as an electrode, and a focus ring 7 that controls an etching range by plasma It is configured.
[0044]
Among these, the chamber wall 2, the shower head 3, the fixing jig 6, the focus ring 7 and the like are in contact with the plasma formed above the wafer, and the boron carbide bonded body of the present invention is used as described above. can do.
[0045]
The member in contact with plasma refers to a member that undergoes corrosion under the influence of ions and active species in the plasma. In particular, it is blocked between the member placed inside the plasma, the container that contains the plasma, or the plasma. Such as a member that does not have an object to be performed.
[0046]
A vacuum vessel is one that is separated from the atmosphere and allows the inside of the vessel to be depressurized to less than 1 atm. In particular, the degree of vacuum is 100 Pa or less, further 1 Pa or less in consideration of the influence of residual gas. A degree of vacuum is preferred. For that purpose, it is preferable to achieve a vacuum state using a vacuum pump for evacuation and to keep the pressure in the container constant with respect to the introduction of gas.
[0047]
Further, the gas introduction device is an equipment for introducing at least a desired gas into the vacuum vessel, and is generally an equipment for introducing a predetermined flow rate of gas from a gas supply facility such as a gas cylinder into the vacuum vessel. The gas flow rate is usually adjusted by a mass flow controller or the like.
[0048]
Furthermore, the plasma generator is a facility for generating an electric field necessary for generating plasma, and particularly generates a high frequency of 1 MHz to 10 GHz, particularly 0.4 to 5 GHz, and further 0.7 to 2.6 GHz. The device and the wiring or waveguide that guides the generated high frequency to the electrode or device.
[0049]
Furthermore, the workpiece fixing jig 6 is for fixing the wafer 5 at a fixed position in order to perform processing such as etching and film formation on the workpiece such as the wafer 5. Or an electrostatic chuck can be used. Further, when the degree of vacuum in the vacuum container is low, a vacuum chuck may be used. As in the example shown in FIG. 1, the fixing jig 6 may also serve as an electrode, or may serve as a heater or have a cooling function.
[0050]
A plasma apparatus such as an etching apparatus configured as described above uses the boron carbide bonded body of the present invention, and by extending the life of a member exposed to a harsh environment and increasing the time until replacement of a part. In addition to reducing the number of stoppages at the time of replacement and increasing the throughput, it is possible to save the cost of the members, and as a result, greatly contribute to the low cost. Moreover, since impurities can be mixed into the plasma, stable processing can be performed.
[0051]
The boron carbide joined body of the present invention has characteristics such as high hardness, high rigidity, and high strength, and boron carbide is used in semiconductor and liquid crystal manufacturing processes and other processing apparatuses that do not use plasma. This characteristic can be fully utilized, and as a result, the apparatus cost and the product cost can be reduced.
[0052]
【Example】
As the boron carbide powder, an A1 material (trade name HS, manufactured by Stark Vitec Co., Ltd.) having a purity of 99.8% and an average particle diameter of 0.8 μm was mainly used. Moreover, A2 raw material (Electrochemical Industry Co., Ltd. product name F2) whose average particle diameter is 8 micrometers was used.
[0053]
In addition, as at least one compound powder selected from Group 4a and 5a elements of the Periodic Table, oxide powders or boride powders having the types and average particle sizes shown in Table 1 were used.
[0054]
Mixing raw material powder composed of at least one oxide powder or borides powder selected from the boron carbide powder and the Periodic Table 4a and 5a group element to, acrylic resin, DBP (di-butyl as a plasticizer as a binder -Phthalate) was added and mixed using a plastic ball to obtain a slurry.
[0055]
On the other hand, a boron carbide sintered body produced by hot pressing under a pressure of 30 MPa and a condition of 2100 ° C. was used as a member used for joining. The relative density was 99.9%, and the bending strength at room temperature was 600 MPa. This boron carbide sintered body was processed into a cube having a side of 20 mm.
[0056]
And after apply | coating said slurry to one surface of a cube, another cube was bonded together and a prism was formed, and this prism was hold | maintained in argon gas for 2 hours by the conditions shown in Table 1, and heat-processed. . For applying the slurry, the slurry was applied to the joint surface using a brush.
[0057]
From the fired boron carbide joined body, a strength test piece was cut out and polished so that the joining surface was positioned at the center in the major axis direction. Then, based on JIS R1601, the strength was measured by a four-point bending test, and this was defined as the bonding strength.
[0058]
The composition of the joint was determined by fluorescent X-ray analysis, and the thickness of the joint was calculated using a photograph taken with a scanning electron microscope (SEM). Further, the average particle diameter of boron carbide was measured using 100 SEM particles. The results are shown in Table 1.
[0059]
[Table 1]

[0060]
Sample No. of the present invention. 3-7 and 9-28 had a bonding strength of 200 MPa or more.
[0061]
On the other hand, Sample No. which does not contain at least one compound selected from Group 4a and 5a elements of the Periodic Table. 1. The content of boron carbide powder was 99.5% by weight, which was outside the scope of the present invention. 2. Sample No. in the scope of the present invention in which the content of boron carbide powder is less than 80% by weight. In No. 8, the bonding strength was 180 MPa or less and did not reach 200 MPa.
[0062]
【The invention's effect】
In the present invention, a joint portion having a specific composition is provided between the boron nitride sintered bodies, and a specific heat treatment can reduce raw materials and processing costs and increase the bonding strength.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of an etching apparatus according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Etching apparatus 2 ... Chamber wall 3 ... Shower head 4 ... High frequency coil 5 ... Wafer 6 ... Fixing jig 7 ... Focus ring

Claims (7)

In a boron carbide joined body obtained by integrating two members made of a boron carbide sintered body through a joint portion, the joint portion has 80 to 99% by weight of boron carbide and a period of 1 to 20% by weight. A boron carbide joined body comprising at least one oxide or boride selected from Group 4a and 5a elements of Table 4. Boron carbide conjugate of claim 1 Symbol placement, wherein the thickness of the joint portion is 100μm or less. The boron carbide joined body according to claim 1 or 2, wherein an average particle diameter of boron carbide in the joined portion is 5 µm or less. Organic binder with respect to a mixture comprising 80 to 99% by weight of boron carbide powder and 1 to 20% by weight of at least one oxide powder or boride powder selected from Group 4a and 5a elements of the Periodic Table Is applied to at least one surface of the joint surfaces of two members made of a boron carbide sintered body, the member joint surfaces are brought into contact with each other, and a temperature of 1900 ° C. or higher in an inert atmosphere. A process for producing a boron carbide joined body characterized by heat-treating. Said average particle size of the boron carbide powder in the mixture is 5μm or less, an average particle diameter of at least one oxide powder or boride powder is selected from the periodic table 4a and 5a group element is 5μm or less The method for producing a boron carbide joined body according to claim 4 . A plasma-resistant member using the boron carbide joined body according to any one of claims 1 to 3 . The boron carbide-assembly according to any one of claims 1 to 3, a plasma apparatus characterized by comprising as a component in the least device.

Images