JP4270477B2 - Method for producing transparent quartz glass - Google Patents
Method for producing transparent quartz glass Download PDFInfo
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- JP4270477B2 JP4270477B2 JP03013196A JP3013196A JP4270477B2 JP 4270477 B2 JP4270477 B2 JP 4270477B2 JP 03013196 A JP03013196 A JP 03013196A JP 3013196 A JP3013196 A JP 3013196A JP 4270477 B2 JP4270477 B2 JP 4270477B2
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- quartz glass
- quartz
- quartz powder
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- powder
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B19/00—Other methods of shaping glass
- C03B19/09—Other methods of shaping glass by fusing powdered glass in a shaping mould
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P40/00—Technologies relating to the processing of minerals
- Y02P40/50—Glass production, e.g. reusing waste heat during processing or shaping
- Y02P40/57—Improving the yield, e-g- reduction of reject rates
Description
【０００１】
【産業上の利用分野】
本発明は、透明石英ガラスの製造方法、さらに詳しくは半導体製品の製造工程で用いる石英ガラス治具の製造に好適な透明石英ガラスの製造方法に関する。
【０００２】
【従来技術】
従来、石英ガラスは高純度で、しかも耐熱性に優れているところから半導体ウエハーの処理工程で使用される石英ガラス治具用素材として使用されてきた。近年、前記半導体ウエハーの処理に使用する石英ガラス治具が肉厚の部材を多く使用するようになり、それを作成するむく棒、管或は板が酸水素火炎中に石英粉を供給しながら溶融堆積させるいわゆるベルヌイ法で製造されていたが、製造時間が長くかかりコスト高になるといった欠点があった。そこで、大型化が可能で、かつ水酸基濃度が低く高温粘度の高い石英ガラスの製造方法である、カーボン製鋳型に石英粉を充填しそれを電気炉を用いて加熱溶融する製造方法（以下カーボン鋳型法という）が提案された。しかし前記製造方法では石英粉がガラス化前にカーボン製鋳型内表面と充填石英粉の接触部分で熱反応が始まり、それが一定の深さまで進行して石英ガラスの外表面に荒れを作ったり、或は前記熱反応で発生した汚染ガスが充填石英粉の隙間を通って内部に移動し石英ガラスの外層部を汚染したりして製品の歩留を低くするといった問題点があった。
【０００３】
【発明が解決しようとする課題】
こうした現状に鑑み、本発明者等は、半導体処理治具製造用の石英ガラスの製造方法について検討を重ねた結果、カーボン鋳型法による石英ガラスの外表面の荒れや外層部の汚染が、カーボン製鋳型と石英粉との熱反応に起因し、その熱反応がカーボン製鋳型と石英粉との接触面積の増大で加速されることがわかった。そして前記外表面の荒れや外層部の汚染がカーボン製鋳型の内周壁と充填石英粉との間に薄肉の透明石英ガラス層を介在させカーボン製鋳型と石英粉を直接接触させないとともに、充填石英粉中に含有する気体を充分排気しながら加熱溶融することで解決することを見出し、本発明を完成したものである。すなわち、
【０００４】
本発明は、外表面の荒れや外層部の汚染が少なく比較的小径の透明石英ガラスを生産性よく製造する方法を提供することを目的とする。
【０００５】
【課題を解決するための手段】
上記目的を達成する本発明は、石英粉をカーボン製鋳型に充填し真空下で加熱溶融する透明な石英ガラスの製造方法において、前記カーボン製鋳型内壁面と充填石英粉との間に石英ガラス層を介在させ、真空下に、充填石英粉層の高さ５ｃｍ当たり少なくとも３０分以上の時間を要して加熱昇温し、石英粉層内の気体を排気しながら、充填石英粉の溶融を下部から上方に順に進行させる透明石英ガラスの製造方法に係る。
【０００６】
上記製造方法で使用する石英粉としては高温粘性に優れ、高純度であることが要求されるところから、精製した高純度の結晶質石英粉を使用するのが好ましい。前記結晶質石英粉としては例えば水晶、珪砂、珪石等を粉砕して得られた粉体を挙げることができるが、特に水晶粉がよい。前記結晶質石英粉はその粒度が５０〜３００μｍの範囲のものを使用する。粒度が５０μｍ未満では石英粉の溶融が速くなり、気泡の含有を助長して好ましくなく、また粒度が３００μｍを超えると均一なガラス化が困難となる。
【０００７】
本発明における製造方法においてカーボン製鋳型に石英粉を充填したとき状態を図１に示す。また、図２に図１のＡーＡ線水平断面図を示す。図１、２において、１はカーボン製鋳型、２は石英ガラス管、３は石英粉、４は石英ガラス板である。本発明の製造方法では、図１のカーボン製鋳型１の内周壁と充填石英粉の間に薄肉の石英ガラス層を介在させ、真空下で充填石英粉層中の気体を排気しながら加熱溶融する方法が採られるが、前記カーボン製鋳型１と石英粉３との間に介在させる石英ガラス層は薄肉の管状、又は管状及び板状からなる透明石英ガラスが好ましい。特に管状の透明石英ガラス層を介在させるのが作業効率からみて好適である。そして前記石英ガラス層は原料の石英粉と同程度の純度を有し、かつ含有されるＯＨ基濃度も３０ｐｐｍ以下とするのがよい。前記ＯＨ基濃度の石英ガラス層を介在することにより真空下での加熱溶融中に石英ガラス層のＯＨ基濃度が低下し、最後には石英粉から得られた石英ガラスと石英ガラス層との境界が判別できない程度まで減少する。また、前記石英ガラス層はカーボン製鋳型に石英ガラス板４を敷いたのちその上に石英ガラス管２を設置するのが特に好ましい。これにより不必要に石英ガラスを研削除去することなく歩留り高く気泡のない透明石英ガラスを製造できる。このように本発明ではカーボン製鋳型内部に石英ガラス層を介在させその内部に石英粉を充填するのでカーボン製鋳型と石英粉とが直接接触することがなく、しかもカーボン製鋳型は表面が滑らかな石英ガラス層と接触するところから、接触面積が減少し、カーボン製鋳型と石英粉との熱反応で発生するガスが少なくなる上に、発生したガスが緻密な石英ガラス層で石英粉充填層内部に移行するのが阻止され、石英ガラスの外表面の荒れや外層部の汚染が少なくなる。
【０００８】
本発明の製造方法における加熱溶融条件は、室温から１６００℃までを２００〜６００℃／時間の昇温速度で、１６００℃〜石英粉の溶融温度までを１０〜１００℃／時間のゆっくりした昇温速度で、充填石英粉層の高さ５ｃｍ当たり３０分以上の時間を要して加熱し、石英粉層内の気体を排気しながら充填石英粉層の下部から上方に加熱源を順次移動しながら加熱溶融することからなる。前記加熱溶融後は降温することなく少なくとも２時間、好ましくは３〜５時間、鋳型内に不活性ガスを導入し真空破壊し、０．５〜３気圧の加圧下に保持する。前記加熱溶融条件をとることにより、充填石英粉中の気体の排気が充分に行われるとともに、溶融中に発生した気体も排気でき気泡のない透明の比較的小径の石英ガラスを外周部の荒れや汚染が少なく生産性よく製造できる。特に前記加熱において充填結晶質石英粉層の下端部を上端部より少なくとも３０℃高い温度に保持すると気体の排気が一段と促進され生産性が向上する。
【０００９】
【発明の実施の態様】
次に具体例に基づいて本発明を詳細に説明するが、本発明はそれにより限定されるものではない。
【００１０】
【実施例】
実施例１
カーボン板上に内径１５５ｍｍ、長さ５００ｍｍのカーボン筒を立てて、その中に外径１５４ｍｍ、肉厚２ｍｍ、長さ５００ｍｍの透明石英ガラス管２（ＯＨ基濃度２８ｐｐｍ、総金属不純物＜２５ｐｐｍ）を挿入し、内部に結晶質石英粉（総金属不純物＜３０ｐｐｍ、粒度分布６０〜２８０μｍ、平均粒径１８０μｍ）を振動を与えながら充填し高さ約４７０ｍｍに詰めた。前記充填物の密度は約１．４５ｇ／ｃｍ3であった。
【００１１】
上記結晶質石英粉を充填したカーボン製鋳型を真空炉内にセットし１×１０-4ｍｍＨｇ以下の真空度まで排気した後、下部ヒーターのみを使用して昇温をスタートした。昇温条件は以下のとおりである。
室温〜１６００℃ ４時間（４００℃／時間）
１６００℃〜１７８０℃ ６時間（３０℃／時間）
１７８０℃保持 ３時間
【００１２】
上記昇温において、１７８０℃に２時間保持したのち、窒素ガスで炉内の真空を破壊し、大気圧に戻し１時間保持し、溶融・冷却終了まで大気圧を維持した。前記昇温加熱における加熱時間は結晶質石英粉層厚さ４７０mmに対して合計１０時間であり、５cm当り約６４分の平均加熱時間であった。
【００１３】
冷却後取り出された石英ガラスには気泡がなく透明な石英ガラスであった。該石英ガラスをその外表面から約１ｍｍまで研削したところ通常のガラス表面があらわれ、その部分をサンプル抽出し純度を測定したところ内部の純度と変わらなかった。さらに上下表面の凹凸部を切り落として外径１５２ｍｍ、長さ２９５ｍｍで重量１１．７８Ｋｇの石英ガラスを得た。この石英ガラスは製造に使用した石英ガラス管と石英粉の合計重量にたいして９０％の歩留であった。このように製造された石英ガラスには外表面荒れや外層部の汚染が少ない上に目視でカーボン製鋳型の損耗が少ないことが観察された。
【００１４】
比較例１
実施例１と同様なカーボン筒でカーボン製鋳型を形成しその中に結晶質石英粉（総金属不純物＜３０ｐｐｍ、粒度分布６０〜２８０μｍ、平均粒径１８０μｍ）を１２．８５ｋｇを充填した。前記充填に際しては振動を与えながら密度を挙げ、高さ約４７０ｍｍに詰めた。前記充填物の密度は約１．４５ｇ／ｃｍ3であった。前記結晶質石英粉の充填されたカーボン鋳型を実施例１と同様に加熱溶融して石英ガラスインゴットを製造した。得られた石英ガラスはカーボンと反応し、外表面が荒れているとともに、中心部と同じ純度の石英ガラスを露出するのに半径で６ｍｍ程度の研削が必要であり、かつ石英ガラスの上下を切り落とす必要があった。その結果得られた石英ガラスの重量は１０．４ｋｇで投入原料当たり８０％の歩留であった。カーボン製鋳型の損耗が大きいことが目視された。
【００１５】
【発明の効果】
本発明の製造方法では、外表面荒れや外層部の汚染が少なく、かつ気泡のない比較的小径の透明石英ガラスをが歩留り高く製造できる。前記透明石英ガラスを素材として作成された半導体処理用石英ガラス治具は高温粘性が高く治具寿命の高いものであった。さらにカーボン製鋳型と石英粉との反応が少ないところからカーボン製鋳型の損耗が少なくカーボン製鋳型を長く使用でき、製造コストを下げることができた。
【図面の簡単な説明】
【図１】図１は、本発明の製造方法における石英粉を充填したカーボン製鋳型の概略図を示す。
【図２】図２は、図１のＡーＡ線水平断面図である。
【符号の説明】
１ カーボン製鋳型
２ ガラス層
３ 充填石英粉
４ ガラス板[0001]
[Industrial application fields]
The present invention relates to a method for producing transparent quartz glass, and more particularly to a method for producing transparent quartz glass suitable for producing a quartz glass jig used in the production process of a semiconductor product.
[0002]
[Prior art]
Conventionally, quartz glass has been used as a material for a quartz glass jig used in a semiconductor wafer processing process because of its high purity and excellent heat resistance. In recent years, the quartz glass jig used for the processing of the semiconductor wafer has used many thick members, and the bar, tube or plate for producing it has supplied quartz powder into the oxyhydrogen flame. Although manufactured by the so-called Bernoulli method for melt deposition, there is a drawback that the manufacturing time is long and the cost is high. Therefore, a method for producing quartz glass that can be increased in size and has a low hydroxyl group concentration and a high high-temperature viscosity, in which a quartz mold is filled with quartz powder and heated and melted using an electric furnace (hereinafter referred to as a carbon mold). Law) was proposed. However, in the above manufacturing method, a thermal reaction starts at the contact portion between the inner surface of the carbon mold and the filled quartz powder before vitrification of the quartz powder, and it progresses to a certain depth to make the outer surface of the quartz glass rough, Alternatively, there is a problem that the contaminated gas generated by the thermal reaction moves to the inside through the gap of the filled quartz powder and contaminates the outer layer portion of the quartz glass to lower the product yield.
[0003]
[Problems to be solved by the invention]
In view of the current situation, the present inventors have repeatedly studied on a method for producing quartz glass for producing semiconductor processing jigs. As a result, the rough surface of the quartz glass and the contamination of the outer layer by the carbon mold method are It was found that due to the thermal reaction between the mold and the quartz powder, the thermal reaction was accelerated by an increase in the contact area between the carbon mold and the quartz powder. Further, the rough surface and contamination of the outer layer are not caused to contact the carbon mold and the quartz powder directly by interposing a thin transparent quartz glass layer between the inner peripheral wall of the carbon mold and the filled quartz powder. The present invention has been completed by finding that the problem can be solved by heating and melting while sufficiently exhausting the gas contained therein. That is,
[0004]
An object of the present invention is to provide a method for producing a relatively small-diameter transparent quartz glass with high productivity with little roughness of the outer surface and contamination of the outer layer portion.
[0005]
[Means for Solving the Problems]
The present invention that achieves the above object provides a method for producing transparent quartz glass in which quartz powder is filled in a carbon mold and heated and melted under vacuum, and a quartz glass layer is disposed between the inner wall surface of the carbon mold and the filled quartz powder. The temperature of the filled quartz powder layer is increased by heating at a time of at least 30 minutes per 5 cm height of the filled quartz powder layer under vacuum, and the melting of the filled quartz powder is performed while exhausting the gas in the quartz powder layer. The present invention relates to a method for producing transparent quartz glass that proceeds in order from the top to the bottom.
[0006]
As the quartz powder used in the above-mentioned production method, it is preferable to use purified high-purity crystalline quartz powder because it is required to have excellent high-temperature viscosity and high purity. Examples of the crystalline quartz powder include powders obtained by pulverizing quartz, silica sand, silica, and the like, and quartz powder is particularly preferable. The crystalline quartz powder having a particle size in the range of 50 to 300 μm is used. If the particle size is less than 50 μm, the melting of the quartz powder is accelerated, which promotes the inclusion of bubbles, and if the particle size exceeds 300 μm, uniform vitrification becomes difficult.
[0007]
FIG. 1 shows the state when the carbon mold is filled with quartz powder in the production method of the present invention. FIG. 2 is a horizontal sectional view taken along line AA in FIG. 1 and 2, 1 is a carbon mold, 2 is a quartz glass tube, 3 is quartz powder, and 4 is a quartz glass plate. In the manufacturing method of the present invention, a thin quartz glass layer is interposed between the inner peripheral wall of the carbon mold 1 shown in FIG. 1 and the filled quartz powder, and the gas in the filled quartz powder layer is heated and melted while evacuating the gas in a vacuum. Although the method is adopted, the quartz glass layer interposed between the carbon mold 1 and the
[0008]
The heating and melting conditions in the production method of the present invention are as follows: room temperature to 1600 ° C. at a heating rate of 200 to 600 ° C./hour; 1600 ° C. to the melting temperature of quartz powder at a slow temperature of 10 to 100 ° C./hour. While heating at a rate of 30 minutes or more per 5 cm in height of the filled quartz powder layer, while exhausting the gas in the quartz powder layer, moving the heating source sequentially from the bottom of the filled quartz powder layer It consists of heating and melting. After the heating and melting, an inert gas is introduced into the mold for vacuum breaking for at least 2 hours, preferably 3 to 5 hours without lowering the temperature, and maintained under a pressure of 0.5 to 3 atmospheres. By taking the heating and melting conditions, the gas in the filled quartz powder is sufficiently exhausted, and the gas generated during the melting can be exhausted, so that a transparent relatively small-diameter quartz glass without bubbles is roughened on the outer periphery. It can be manufactured with low contamination and high productivity. In particular, when the lower end portion of the filled crystalline quartz powder layer is maintained at a temperature that is at least 30 ° C. higher than the upper end portion in the heating, gas exhaust is further promoted and productivity is improved.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, the present invention will be described in detail based on specific examples, but the present invention is not limited thereto.
[0010]
【Example】
Example 1
A carbon tube having an inner diameter of 155 mm and a length of 500 mm is set up on a carbon plate, and an outer diameter of 154 mm, a thickness of 2 mm, and a length of 500 mm of a transparent quartz glass tube 2 (OH group concentration: 28 ppm, total metal impurities <25 ppm) It was inserted and filled with crystalline quartz powder (total metal impurities <30 ppm, particle size distribution 60-280 μm, average particle size 180 μm) while vibrating and packed to a height of about 470 mm. The density of the packing was about 1.45 g / cm 3 .
[0011]
The carbon mold filled with the crystalline quartz powder was set in a vacuum furnace and evacuated to a vacuum of 1 × 10 −4 mmHg or less, and then the temperature was raised using only the lower heater. The temperature raising conditions are as follows.
Room temperature to 1600 °
1600 ° C to 1780 ° C for 6 hours (30 ° C / hour)
Hold at 1780 ° C for 3 hours [0012]
After maintaining at 1780 ° C. for 2 hours at the above temperature increase, the vacuum in the furnace was broken with nitrogen gas, returned to atmospheric pressure and maintained for 1 hour , and maintained at atmospheric pressure until melting and cooling were completed. The heating time in the temperature raising heating was 10 hours in total with respect to the crystalline quartz powder layer thickness of 470 mm, and the average heating time was about 64 minutes per 5 cm.
[0013]
The quartz glass taken out after cooling was transparent quartz glass without bubbles. When the quartz glass was ground from the outer surface to about 1 mm, a normal glass surface appeared. When the portion was sampled and the purity was measured, it was not different from the internal purity. Further, the concave and convex portions on the upper and lower surfaces were cut off to obtain quartz glass having an outer diameter of 152 mm, a length of 295 mm, and a weight of 11.78 kg. This quartz glass had a yield of 90% with respect to the total weight of the quartz glass tube and the quartz powder used for production. It was observed that the quartz glass produced in this manner had less rough outer surface and less contamination of the outer layer portion, and that the carbon mold was less worn visually.
[0014]
Comparative Example 1
A carbon mold was formed with the same carbon cylinder as in Example 1, and 12.85 kg of crystalline quartz powder (total metal impurities <30 ppm, particle size distribution 60 to 280 μm, average particle size 180 μm) was filled therein. During the filling, the density was increased while applying vibration, and the height was packed to about 470 mm. The density of the packing was about 1.45 g / cm 3 . The carbon mold filled with the crystalline quartz powder was heated and melted in the same manner as in Example 1 to produce a quartz glass ingot. The obtained quartz glass reacts with carbon, and the outer surface is rough. In addition, to expose the quartz glass having the same purity as that of the central portion, grinding with a radius of about 6 mm is necessary, and the quartz glass is cut off at the top and bottom. There was a need. As a result, the weight of quartz glass obtained was 10.4 kg, and the yield was 80% per input raw material. It was visually observed that the carbon mold was heavily worn.
[0015]
【The invention's effect】
According to the production method of the present invention, it is possible to produce a transparent quartz glass having a relatively small diameter with little roughness on the outer surface and no contamination of the outer layer and having no bubbles, with a high yield. The quartz glass jig for semiconductor processing prepared using the transparent quartz glass as a raw material has a high temperature viscosity and a long jig life. Further, since the reaction between the carbon mold and the quartz powder is small, the carbon mold is less worn and the carbon mold can be used for a long time, and the production cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a schematic view of a carbon mold filled with quartz powder in the production method of the present invention.
FIG. 2 is a horizontal cross-sectional view taken along line AA in FIG.
[Explanation of symbols]
1
Claims (5)
室温から１６００℃まで ２００〜６００℃／時間
１６００℃〜石英粉の溶融温度まで １０〜１００℃／時間
とすることを特徴とする請求項１又は２記載の透明石英ガラスの製造方法。The transparent quartz according to claim 1 or 2, wherein the heating temperature rising rate in the mold is from room temperature to 1600 ° C, from 200 to 600 ° C / hour, from 1600 ° C to the melting temperature of the quartz powder, from 10 to 100 ° C / hour. Glass manufacturing method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03013196A JP4270477B2 (en) | 1996-01-25 | 1996-01-25 | Method for producing transparent quartz glass |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03013196A JP4270477B2 (en) | 1996-01-25 | 1996-01-25 | Method for producing transparent quartz glass |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09202631A JPH09202631A (en) | 1997-08-05 |
| JP4270477B2 true JP4270477B2 (en) | 2009-06-03 |
Family
ID=12295231
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP03013196A Expired - Fee Related JP4270477B2 (en) | 1996-01-25 | 1996-01-25 | Method for producing transparent quartz glass |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4270477B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19855915C5 (en) * | 1997-12-03 | 2009-09-24 | Tosoh Corp., Shinnanyo | Transparent high-purity quartz glass and process for its production |
| KR101642327B1 (en) * | 2014-09-23 | 2016-07-26 | (주) 디에스테크노 | Apparatus for manufacturing high purity quartz glass |
| KR101642323B1 (en) * | 2014-09-23 | 2016-07-26 | (주) 디에스테크노 | The method for manufacturing high purity quartz glass |
-
1996
- 1996-01-25 JP JP03013196A patent/JP4270477B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH09202631A (en) | 1997-08-05 |
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