JP3618048B2 - Components for semiconductor manufacturing equipment - Google Patents
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Description
【０００１】
【発明の属する技術分野】
本発明は、特にフッ素系・塩素系プラズマに対して高い耐食性を有し、パーティクルやコンタミネーションの発生が少ない、プラズマ処理装置などの半導体製造用装置の内壁部材や被処理物を支持する支持体などの治具等としての使用に好適な高密度フッ化物焼結体を用いた半導体製造装置用部材に関するものである。
【０００２】
【従来の技術】
半導体素子や液晶などの高集積回路形成に使用されるドライプロセスやプラズマコーティング等プラズマの利用が近年急速に進んでいる。半導体におけるプラズマプロセスとしては、フッ素系等のハロゲン系腐食ガスがその反応性の高さから、気相成長、エッチングやクリーニングに利用されている。
【０００３】
これら腐食性ガスに接触する部材は、高い耐食性が要求され、従来から被処理物以外のこれらプラズマに接触する部材は、一般にガラスや石英などのＳｉＯ２ を主成分とする材料やステンレス、モネル等の金属が多用されている。
【０００４】
また、半導体製造時において、ウェハを支持固定するサセプタ材としてアルミナ質焼結体、サファイア、ＡｌＮ質焼結体、窒化珪素等の珪素質焼結体またはこれらをＣＶＤ法等により表面被覆したものが耐食性に優れるとして使用されている。また、グラファイト、窒化硼素をコーティングしたヒータ等も使用されている。
【０００５】
さらに、特開平８−９１９３２号公報では、腐食性ガスに接触する部材として、アルミニウム系材料のプラズマとの生成物であるＡｌＦ３ の焼結体を使用することにより耐プラズマ性が向上することが開示されている。
【０００６】
【発明が解決しようとする課題】
しかし、従来から用いられているガラスや石英ではプラズマ中の耐食性が不充分で消耗が激しく、特にフッ素あるいは塩素プラズマに接すると接触面がエッチングされ、表面性状が変化してエッチングに影響する等の問題が生じていた。
【０００７】
また、ステンレスなどの金属を使用した部材でも耐食性が不充分なため、腐食によって特に半導体製造においては不良品発生の原因となっていた。アルミナ、窒化アルミニウム、窒化珪素質焼結体やコーティング材は、上記の材料に比較してフッ素系ガスに対して耐食性に優れるものの、高温でプラズマと接すると腐食が徐々に進行して焼結体の表面から結晶粒子の脱粒が生じたり、プラズマとの反応生成物が析出・剥離してパーティクル発生の原因になるという問題が起きていた。
【０００８】
このようなパーティクルの発生は、半導体の高集積化、プロセスのさらなるクリーン化が図られる中、イオン衝撃や、気相反応で生成したごく微細なパーティクルによってメタル配線の断線、パターンの欠陥等による素子特性の劣化や歩留まりの低下等の不具合を発生する恐れが生じている。
【０００９】
また、特開平８−９１９３２号公報のように、腐食性ガスに接触する部材として、ＡｌＦ３ の焼結体を使用した場合、ＡｌＦ３ は、比較的低温から昇華するため高温領域では不安定となることから、アルミナ、窒化アルミニウム、窒化珪素質焼結体に比べ耐食性が向上するものの、実用的には充分でなかった。さらに、ＡｌＦ３ （融点１０４０℃）は、比較的低温で昇華することから、特に常圧焼成やホットプレス焼成等の雰囲気焼成においては、昇華を抑制しつつ焼成する必要があり、緻密な焼結体を得ることが難しいものであった。
【００１０】
本発明者らは、このような問題を解決するため、先にフッ素・塩素系プラズマと接触する表面をプラズマに対して安定なハロゲン化物を形成しうる周期律表第２Ａ、３Ａ族元素を含有する酸化物、窒化物、炭化物の焼結体により形成し、プラズマにより焼結体表面にＣａＦ２ 等の周期律表第２Ａ、３Ａ族元素を含有するハロゲン化物を形成することを提案した。
【００１１】
しかしながら、周期律表第２Ａ、３Ａ族元素を主成分とする材料は、フッ素・塩素系のプラズマに対しては安定ではあっても、室温における熱膨張係数が、例えば、酸化マグネシウム１４×１０−６／℃、フッ化マグネシウム１０×１０−６／℃と差があるために、熱サイクルにより焼結体表面に形成された周期律表第２Ａ、３Ａ族元素を含有するハロゲン化物が剥離しやすく、材料表面に形成されたハロゲン化物の脱落によってパーティクルが発生してしまうという問題があった。
【００１２】
特に、ＣａＦ２ の溶融体は、へき開性があるため、表面層等が振動や衝撃等により容易に剥離し、多量のパーティクルの発生の要因となっていた。
【００１３】
【課題を解決するための手段】
本発明者らは、フッ素系及び塩素系腐食プラズマに対して、高い耐食性を有し、パーティクルの発生を抑制できる材料について検討を重ねた結果、アルカリ土類金属のフッ化物焼結体の結晶粒径、不純物量および密度を特定の範囲に制御することにより、フッ素・塩素系腐食プラズマに対して高い耐食性を示し、パーティクルの発生を抑制して半導体素子の汚染を抑制した半導体製造装置用部材が得られることを見いだした。
【００１４】
すなわち、本発明の高密度フッ化物焼結体は、少なくともハロゲン系腐食ガスあるいはそのプラズマと直接接触する表面を具備し、Ｍｇ、Ｃａ、ＳｒおよびＢａの群から選ばれる少なくとも１種のアルカリ土類金属のフッ化物からなり、前記アルカリ土類金属以外の金属元素の総量が金属換算で１００ｐｐｍ以下、前記フッ化物の結晶粒子の平均粒径が３０μｍ以下であり、かつ相対密度が９５％以上の高密度フッ化物焼結体からなることを特徴とするものである。
【００１５】
また、前記高密度フッ化物焼結体の開気孔率が０．２％以下であることが好ましい。
【００１６】
さらに、前記高密度フッ化物焼結体の表面粗さＲａが１μｍ以下であることが好ましい。
【００１７】
【発明の実施の形態】
本発明の半導体製造装置用部材は、少なくともハロゲン系腐食ガスあるいはそのプラズマと直接接触する表面を具備し、Ｍｇ、Ｃａ、ＳｒおよびＢａの群から選ばれる少なくとも１種のアルカリ土類金属のフッ化物からなるもので、ハロゲン系プラズマ、特にフッ素プラズマに対する耐食性の観点から、前記アルカリ土類金属以外の金属元素の総量を金属換算で１００ｐｐｍ以下、望ましくは９０ｐｐｍ以下、特に５０ｐｐｍ以下、さらには１０ｐｐｍ以下に制御することが重要である。すなわち、前記アルカリ土類金属以外の金属元素の総量が金属換算で１００ｐｐｍより多いと、プラズマ接触面でアルカリ土類金属以外の金属がプラズマと反応し、これによりエッチングが進行するとともに、その反応物がパーティクルの原因となるためである。
【００１８】
また、フッ素プラズマに対する耐食性の点では、融点の高い材料が望ましく、ＣａＦ２ 、ＭｇＦ２ 、ＢａＦ２ 、ＳｒＦ２ （それぞれの融点１３６０℃、１２６５℃、１２８０℃、１１９０℃）の順で好ましい。
【００１９】
さらに、プラズマに対する耐食性を高める上では、焼結体の相対密度は９５％以上、特に９８％以上であることが必要がある。これは、焼結体の相対密度が９５％より小さいと、プラズマとの接触面積が増加するために耐食性が低下し、またプラズマ接触面に存在する気孔からエッチングが進行してしまうためである。
【００２０】
また、焼結体のフッ化物結晶の平均粒径は、３０μｍ以下、望ましくは２５μｍ以下、特に１０μｍ以下、さらには５μｍ以下であることが望ましい。すなわち、この平均粒径が３０μｍより大きいと、脱粒等が発生した場合、半導体製造装置内に及ぼす影響が大きくなるためである。
【００２１】
かかるハロゲン系プラズマに対し、高い耐食性を有する高密度フッ化物焼結体を作製する方法としては、アルカリ土類金属以外の金属元素の総量を金属換算で１００ｐｐｍ以下、望ましくは９０ｐｐｍ以下、特に５０ｐｐｍ以下、さらには１０ｐｐｍ以下であり、かつ平均粒径が３０μｍ以下、望ましくは２０μｍ以下、特に１０μｍ以下、さらには３μｍ以下のフッ化物原料粉末を準備する。原料粉末の粒径が３０μｍよりも大きい場合は、所望の粉砕方法、例えば、ボールミル、振動ミル、アトライタミル、ジェットミル等により粉砕して用いればよく、また、メッシュパス等により粗粒を除去しておくほうが望ましい。
【００２２】
この粉末を用いて、所定形状に所望の成形手段、例えば、金型プレス、冷間静水圧プレス、押し出し成形等により任意の形状に成形する。この時の成形体は、相対密度５５％以上であることが望ましく、成形体密度が５５％よりも低いと、その後の焼結過程で相対密度９５％以上の緻密体を作製することが困難である。
【００２３】
次に、上記のようにして作製した成形体を相対密度９５％以上、特に９８％以上に焼成する。相対密度９５％以上に緻密化するには、上記の組成からなる成形体を非酸化性雰囲気中、加圧あるいは常圧下（非酸化性ガス圧１ａｔｍ以上）で７００〜１３００℃の温度範囲で焼成することにより得られる。
【００２４】
この場合、最適な焼成温度は材料によって異なり、例えば、ＭｇＦ２ およびＢａＦ２ については７００〜１２００℃、好ましくは８００〜１１００℃、さらには９００〜１０００℃が望ましく、ＣａＦ２ については、８００〜１３００℃、好ましくは９００〜１２００℃、さらには１０００〜１１００℃が望ましく、ＳｒＦ２ については、８００〜１１００℃、好ましくは８５０〜１０５０℃、さらには９００〜１０００℃が望ましい。なお、ＡｌＦ３ については、融点が１０４０℃であり、かつ昇華しやすいため、焼成温度を１０４０℃以上に上げることができないため焼成により緻密化させることが難しい。
【００２５】
また、上記焼成において、相対密度を向上させるためには５０ｋｇｆ／ｃｍ２ 以上の加圧下でホットプレス焼成することが望ましく、さらに、得られた焼結体に対して熱間静水圧焼成を行ってもよい。
【００２６】
なお、ホットプレスの場合、カーボンモールドによって焼結体中にわずかにカーボンが混入する場合があるが、その量は０．５重量％以下であれば特に問題ない。
【００２７】
上記の焼成により、相対密度９５％以上、特に９８％以上の焼結体を得る。なお、上記焼結体が低密度で多量の気孔を有する場合は、それだけガスやプラズマとの接触面積が増加し消耗が早くなるため、開気孔率０．２％以下であることが望ましい。得られた焼結体に対し、適宜研削加工を施し、所定の寸法の製品形状に仕上げる。この時、耐食性を高める上では、前記腐食性ガスあるいはそのプラズマと接触する焼結体表面の表面粗さ（Ｒａ）が、１μｍ以下、特に０．５μｍ以下、さらには０．１μｍ以下であることが望ましい。
【００２８】
そして、かかる高密度フッ化物焼結体は、半導体素子を製造する際に用いられ、フッ素系または塩素系等のハロゲン系の腐食ガスまたはプラズマと表面が直接接触する部位に好適に用いられる。フッ素系ガスとしては、ＳＦ６ 、ＮＦ３ 、ＣＦ４ 、ＣＨＦ３ 、ＣｌＦ３ 、ＨＦ等が、また塩素系ガスとしては、Ｃｌ２ 、ＢＣｌ３ 、ＨＣｌ等が挙げられ、これらのガスが導入された雰囲気にマイクロ波や高周波等を導入するとこれらのガスがプラズマ化される。
【００２９】
本発明によれば、このようなハロゲン系の腐食ガスあるいはそのプラズマに直接接触する表面を、フッ化物焼結体から構成するものである。フッ化物焼結体は、フッ素、塩素との反応性が低いために、優れた耐食性を示す。
【００３０】
さらに、シリコンウェハの大口径化に伴い、製造装置や構成部品自体も大型化することから、強度および耐熱衝撃性を高める必要があり、また、塩素系ガス及びそのプラズマを使用する場合は、熱サイクルによる部品の劣化が問題視されてくることから耐熱信頼性を高める上でも、焼結体の相対密度は９５％以上が必要である。
【００３１】
【実施例】
（実施例１）
表１に示す平均粒径、アルカリ土類金属以外の金属含有量（不純物量と記す）のフッ化物原料粉末を用い、これをカーボン製モールドに充填し、真空中、２００ｋｇｆ／ｃｍ２ の加圧下、表１に示す焼成温度にて２時間ホットプレス焼成を行った。
【００３２】
比較例として、純度９９．９９％以上のＣａＦ２ の溶融体（試料Ｎｏ．３２）を準備した。また、ＳｉＯ２ 、Ａｌ２ Ｏ３ 、ＡｌＮ、ＡｌＦ３ について、表１に示す温度で焼成し同様に溶融体あるいは焼結体を作製した（試料Ｎｏ．２８〜３１）。
【００３３】
得られた焼結体を用いて、まずアルキメデス法により焼結体の密度を測定し、理論密度に対する比率である相対密度（％）を算出した。結果は表１に示した。
【００３４】
（耐食性試験）
得られた焼結体に対して、表面を表面粗さ（Ｒａ）が０．１μｍ以下となるように鏡面加工した直径２２ｃｍの円盤を作製し、ＲＩＥプラズマエッチング装置にて、ＣＦ４ （６０ｓｃｃｍ）＋ Ａｒ（６０ｓｃｃｍ）のフッ素系プラズマに室温で曝し、エッチングレートとパーティクルの有無を調査した。エッチング条件は圧力１０Ｐａ、ＲＦ出力１ＫＷ、プラズマ照射時間３時間とした。エッチングレートはテスト前後の重量変化を基に算出した。パーティクルの有無は、プラズマ照射後の円盤上に８インチのＳｉウェハを載せたのち、ウェハの接触面の凹凸をレーザー散乱によって検出し、パーティクルカウンタにて０．３μｍ以上のパーティクル個数を計測した。結果を表１に示す。
【００３５】
【表１】
表１の結果によれば、試料Ｎｏ．１、９は、焼成温度が低く、相対密度を９５％以上に緻密化できないために、耐食性が低下するとともに脱粒によって３０個以上のパーティクルが発生し、使用に耐えない。また、試料Ｎｏ．２３は、焼成温度が高く溶融してしまった。さらに、原料粉末の粒径が３０μｍを越える試料Ｎｏ．６、１４、２２、２７では、緻密化できず、耐食性が低下した。また、アルカリ土類金属以外の金属元素の総量が金属換算で１００ｐｐｍより多い試料Ｎｏ．５、１３は、多量のパーティクルの発生が認められた。
【００３７】
一方、アルカリ土類金属のフッ化物以外のＳｉＯ２ 、Ａｌ２ Ｏ３ 、ＡｌＮ、ＡｌＦ３ の焼結体およびＣａＦ２ の溶融体については、緻密な焼結体が得られるものの、耐食性は不十分であった。
【００３８】
これに対し、本発明による試料Ｎｏ．２〜４、７〜８、１０〜１２、１５〜２１、２４〜２６は、相対密度９５％以上、かつエッチングレート２５Å／ｍｉｎ．以下、特に１５Å／ｍｉｎ．以下、パーティクル発生量１５個／８インチウエハ、特に１０個／８インチウエハの良好な耐食性を示した。
【００３９】
（実施例２）
平均粒径１０μｍ、焼結体中におけるアルカリ土類金属以外の金属元素含有量（不純物量）８３ｐｐｍのＣａＦ２ 粉末を用い、３ｔｏｎ／ｃｍ２ の圧力でＣＩＰ処理を行った後、Ａｒ雰囲気中、焼成温度１１００℃にて雰囲気焼成（ＰＬＳ）を行った。得られた試料について、実施例１と同様の評価を行ったところ、相対密度９５％、結晶の平均粒径１３μｍ、エッチングレート２２Å／ｍｉｎ．、パーティクル発生量１５個／８インチウエハの良好な耐食性を示した。
【００４０】
【発明の効果】
以上詳述したように、本発明によれば、フッ素系及び塩素系腐食性ガス或いはプラズマに曝される部材としてＭｇ、Ｃａ、ＳｒおよびＢａの群から選ばれる少なくとも１種のアルカリ土類金属のフッ化物からなり、前記アルカリ土類金属以外の金属元素の総量が金属換算で１００ｐｐｍ以下であり、平均粒径が３０μｍ以下、かつ相対密度９５％以上の焼結体を使用することにより、高温・高密度のフッ素系及び塩素系腐食雰囲気に長時間の耐久性を有し、且つコンタミネーションやパーティクルを発生しないこと、大型部品としての機械的強度を保持することから、半導体製造用装置、とりわけプラズマ処理装置の内壁部材や被処理物を支持する支持体などの治具等の部材として使用することにより、半導体製造の歩留り向上とともに高品質の半導体素子を作製することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention is a support for supporting an inner wall member or an object to be processed of a semiconductor manufacturing apparatus such as a plasma processing apparatus, which has high corrosion resistance particularly against fluorine-based and chlorine-based plasma and generates less particles and contamination. It is related with the member for semiconductor manufacturing apparatuses using the high-density fluoride sintered compact suitable for use as jigs.
[0002]
[Prior art]
In recent years, the use of plasma such as dry process and plasma coating used for forming highly integrated circuits such as semiconductor elements and liquid crystals has been rapidly progressing. As plasma processes in semiconductors, halogen-based corrosive gases such as fluorine are used for vapor phase growth, etching and cleaning because of their high reactivity.
[0003]
These members that come into contact with corrosive gases are required to have high corrosion resistance. Conventionally, members that come into contact with these plasmas other than the object to be processed are generally made of materials mainly composed of SiO 2 such as glass and quartz, stainless steel, monel, etc. Often used.
[0004]
Also, during semiconductor manufacturing, as a susceptor material for supporting and fixing a wafer, an alumina sintered body, a sapphire, an AlN sintered body, a silicon sintered body such as silicon nitride, or the like, which is surface-coated by a CVD method or the like. It is used as having excellent corrosion resistance. In addition, heaters coated with graphite and boron nitride are also used.
[0005]
Furthermore, in JP-A-8-91932, plasma resistance is improved by using a sintered body of AlF 3 which is a product of plasma of an aluminum-based material as a member that contacts a corrosive gas. It is disclosed.
[0006]
[Problems to be solved by the invention]
However, conventionally used glass and quartz have insufficient corrosion resistance in the plasma and are very exhausted, especially when they come into contact with fluorine or chlorine plasma, the contact surface is etched, the surface properties change and affect the etching, etc. There was a problem.
[0007]
Further, even a member using a metal such as stainless steel has insufficient corrosion resistance, so that corrosion has caused a defective product particularly in semiconductor manufacturing. Alumina, aluminum nitride, silicon nitride-based sintered bodies and coating materials are superior in corrosion resistance to fluorine-based gases compared to the above materials. There have been problems that crystal grains are shed from the surface, and that a reaction product with plasma is precipitated and separated to cause generation of particles.
[0008]
The generation of such particles is due to the high integration of semiconductors and the further cleanliness of the process, the element caused by ion bombardment, disconnection of metal wiring, pattern defects, etc. due to very fine particles generated by gas phase reaction. There is a possibility that problems such as deterioration of characteristics and a decrease in yield occur.
[0009]
Also, as in JP-8-91932 and JP-as a member for contacting the corrosive gas, when using the sintered body of AlF 3, AlF 3 is unstable in the high temperature region for sublimation from a relatively low temperature Therefore, although the corrosion resistance is improved as compared with alumina, aluminum nitride, and silicon nitride sintered body, it is not sufficient for practical use. Furthermore, since AlF 3 (melting point 1040 ° C.) sublimes at a relatively low temperature, it is necessary to perform firing while suppressing sublimation, particularly in atmospheric firing such as atmospheric pressure firing and hot press firing, and dense sintering. It was difficult to get a body.
[0010]
In order to solve such a problem, the inventors of the present invention include elements 2A and 3A in the periodic table that can form a halide that is stable against the plasma on the surface that comes into contact with the fluorine-chlorine plasma. It was proposed to form a halide containing 2A, 3A group elements of the periodic table such as CaF 2 on the surface of the sintered body by plasma.
[0011]
However, although the material mainly composed of Group 2A and 3A elements of the periodic table is stable against fluorine / chlorine plasma, the thermal expansion coefficient at room temperature is, for example, magnesium oxide 14 × 10 − Since there is a difference between 6 / ° C. and magnesium fluoride 10 × 10 −6 / ° C., the halide containing 2A and 3A group elements of the periodic table formed on the surface of the sintered body by thermal cycling is easy to peel off. There has been a problem that particles are generated by the falling off of the halide formed on the material surface.
[0012]
In particular, since the CaF 2 melt has a cleavage property, the surface layer and the like easily peeled off due to vibration, impact, and the like, causing a large amount of particles to be generated.
[0013]
[Means for Solving the Problems]
As a result of repeated investigations on materials that have high corrosion resistance against fluorine-based and chlorine-based corrosive plasma and that can suppress the generation of particles, the inventors have found that the crystal grains of the alkaline earth metal fluoride sintered body By controlling the diameter, impurity amount, and density to a specific range, a member for a semiconductor manufacturing apparatus that exhibits high corrosion resistance against fluorine / chlorine-based corrosive plasma and suppresses the generation of particles to suppress contamination of semiconductor elements. I found out that I could get it.
[0014]
That is, the high-density fluoride sintered body of the present invention has at least a surface that is in direct contact with a halogen-based corrosive gas or plasma thereof, and at least one alkaline earth selected from the group consisting of Mg, Ca, Sr, and Ba. It is made of a metal fluoride, the total amount of metal elements other than the alkaline earth metal is 100 ppm or less in terms of metal, the average particle diameter of the fluoride crystal particles is 30 μm or less, and the relative density is 95% or more. It consists of a density fluoride sintered compact .
[0015]
The open porosity of the high-density fluoride sintered body is preferably 0.2% or less.
[0016]
Furthermore, the surface roughness Ra of the high-density fluoride sintered body is preferably 1 μm or less.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Semiconductors manufacturing equipment member of the present invention comprises a surface which contacts at least a halogen-based corrosive gas or directly with the plasma, Mg, Ca, at least one alkaline earth metal fluoride selected from the group consisting of Sr and Ba From the viewpoint of corrosion resistance to halogen-based plasma, particularly fluorine plasma, the total amount of metal elements other than the alkaline earth metal is 100 ppm or less, desirably 90 ppm or less, particularly 50 ppm or less, more preferably 10 ppm or less. It is important to control. That is, when the total amount of the metal elements other than the alkaline earth metal is more than 100 ppm in terms of metal, the metal other than the alkaline earth metal reacts with the plasma at the plasma contact surface, whereby the etching proceeds and the reaction product This is because it causes particles.
[0018]
Further, in terms of corrosion resistance against fluorine plasma, a material having a high melting point is desirable, and CaF 2 , MgF 2 , BaF 2 , SrF 2 (respective melting points 1360 ° C., 1265 ° C., 1280 ° C., 1190 ° C.) are preferable in this order.
[0019]
Furthermore, in order to improve the corrosion resistance against plasma, the relative density of the sintered body needs to be 95% or more, particularly 98% or more. This is because when the relative density of the sintered body is less than 95%, the contact area with the plasma is increased, so that the corrosion resistance is lowered, and the etching proceeds from the pores existing on the plasma contact surface.
[0020]
The average particle size of the fluoride crystals of the sintered body is 30 μm or less, desirably 25 μm or less, particularly 10 μm or less, and further desirably 5 μm or less. That is, when the average particle size is larger than 30 μm, the effect on the semiconductor manufacturing apparatus increases when degranulation occurs.
[0021]
As a method for producing a high-density fluoride sintered body having high corrosion resistance against such halogen-based plasma, the total amount of metal elements other than alkaline earth metals is 100 ppm or less, desirably 90 ppm or less, particularly 50 ppm or less in terms of metal. Further, a fluoride raw material powder having 10 ppm or less and an average particle size of 30 μm or less, desirably 20 μm or less, particularly 10 μm or less, and further 3 μm or less is prepared. When the particle size of the raw material powder is larger than 30 μm, it may be used after being pulverized by a desired pulverization method, for example, a ball mill, a vibration mill, an attritor mill, a jet mill, etc. It is better to leave it.
[0022]
Using this powder, it is formed into a desired shape by a desired forming means such as a die press, cold isostatic pressing, extrusion molding or the like. The molded body at this time desirably has a relative density of 55% or more. If the density of the molded body is lower than 55%, it is difficult to produce a dense body having a relative density of 95% or more in the subsequent sintering process. is there.
[0023]
Next, the molded body produced as described above is fired to a relative density of 95% or more, particularly 98% or more. For densification to a relative density of 95% or more, the molded product having the above composition is fired in a non-oxidizing atmosphere under a pressure or normal pressure (non-oxidizing gas pressure of 1 atm or more) in a temperature range of 700 to 1300 ° C. Can be obtained.
[0024]
In this case, the optimum firing temperature varies depending on the material, for example, 700 to 1200 ° C., preferably 800 to 1100 ° C., more preferably 900 to 1000 ° C. for MgF 2 and BaF 2 , and 800 to 1300 for CaF 2. ° C, preferably 900 to 1200 ° C, more preferably 1000 to 1100 ° C, and SrF 2 is 800 to 1100 ° C, preferably 850 to 1050 ° C, more preferably 900 to 1000 ° C. Since AlF 3 has a melting point of 1040 ° C. and is easily sublimated, the firing temperature cannot be increased to 1040 ° C. or higher, and it is difficult to make it dense by firing.
[0025]
Further, in the above firing, in order to improve the relative density, it is desirable to perform hot press firing under a pressure of 50 kgf / cm 2 or more, and further, hot isostatic firing is performed on the obtained sintered body. Also good.
[0026]
In the case of hot pressing, carbon may be slightly mixed in the sintered body by the carbon mold, but there is no particular problem if the amount is 0.5% by weight or less.
[0027]
By the firing, a sintered body having a relative density of 95% or more, particularly 98% or more is obtained. When the sintered body has a low density and a large amount of pores, the contact area with the gas or plasma increases correspondingly and the wear becomes faster. Therefore, the open porosity is preferably 0.2% or less. The obtained sintered body is appropriately ground and finished into a product shape having a predetermined dimension. At this time, in order to improve the corrosion resistance, the surface roughness (Ra) of the surface of the sintered body that is in contact with the corrosive gas or plasma thereof is 1 μm or less, particularly 0.5 μm or less, and further 0.1 μm or less. Is desirable.
[0028]
Such a high-density fluoride sintered body is used when manufacturing a semiconductor element, and is preferably used in a portion where the surface directly contacts with a halogen-based corrosive gas or plasma such as fluorine-based or chlorine-based. Examples of the fluorine-based gas include SF 6 , NF 3 , CF 4 , CHF 3 , ClF 3 , and HF. Examples of the chlorine-based gas include Cl 2 , BCl 3 , and HCl, and these gases are introduced. When microwaves or high frequencies are introduced into the atmosphere, these gases are turned into plasma.
[0029]
According to the present invention, the surface directly in contact with such a halogen-based corrosive gas or its plasma is formed of a fluoride sintered body. Since the fluoride sintered body has low reactivity with fluorine and chlorine, it exhibits excellent corrosion resistance.
[0030]
Furthermore, as the diameter of silicon wafers increases, the manufacturing equipment and components themselves become larger, so it is necessary to increase the strength and thermal shock resistance, and when using chlorine-based gas and its plasma, Since the deterioration of parts due to the cycle is regarded as a problem, the relative density of the sintered body needs to be 95% or more in order to improve the heat resistance reliability.
[0031]
【Example】
Example 1
Using a fluoride raw material powder having an average particle size and a metal content (referred to as impurity amount) other than the alkaline earth metal shown in Table 1, this was filled into a carbon mold and subjected to a pressure of 200 kgf / cm 2 in vacuum. The hot press firing was performed at the firing temperature shown in Table 1 for 2 hours.
[0032]
As a comparative example, a CaF 2 melt (sample No. 32) having a purity of 99.99% or more was prepared. Further, SiO 2, Al 2 O 3 , AlN, for AlF 3, and baked at a temperature shown in Table 1 were prepared melt or sinter in the same manner (Sample No.28~31).
[0033]
Using the obtained sintered body, first, the density of the sintered body was measured by the Archimedes method, and the relative density (%), which is the ratio to the theoretical density, was calculated. The results are shown in Table 1.
[0034]
(Corrosion resistance test)
For the obtained sintered body, a disk having a diameter of 22 cm was produced by mirror-finishing the surface so that the surface roughness (Ra) was 0.1 μm or less, and CF 4 (60 sccm) was produced using an RIE plasma etching apparatus. The substrate was exposed to fluorine plasma of + Ar (60 sccm) at room temperature, and the etching rate and the presence or absence of particles were investigated. Etching conditions were a pressure of 10 Pa, an RF output of 1 kW, and a plasma irradiation time of 3 hours. The etching rate was calculated based on the weight change before and after the test. Presence / absence of particles was determined by placing an 8-inch Si wafer on the plasma-irradiated disk, then detecting irregularities on the contact surface of the wafer by laser scattering, and measuring the number of particles of 0.3 μm or more with a particle counter. The results are shown in Table 1.
[0035]
[Table 1]
According to the results in Table 1, sample No. In Nos. 1 and 9, the firing temperature is low and the relative density cannot be densified to 95% or more, so that the corrosion resistance is lowered and 30 or more particles are generated by degranulation and cannot be used. Sample No. No. 23 was melted at a high firing temperature. Furthermore, the sample No. with the particle size of the raw material powder exceeding 30 μm. 6, 14, 22, and 27 could not be densified, and the corrosion resistance decreased. In addition, Sample No. in which the total amount of metal elements other than alkaline earth metal is more than 100 ppm in terms of metal. In Nos. 5 and 13, generation of a large amount of particles was observed.
[0037]
On the other hand, with respect to a sintered body of SiO 2 , Al 2 O 3 , AlN, AlF 3 and a molten body of CaF 2 other than the alkaline earth metal fluoride, a dense sintered body is obtained, but the corrosion resistance is insufficient. Met.
[0038]
On the other hand, sample no. 2 to 4, 7 to 8, 10 to 12, 15 to 21, and 24 to 26 have a relative density of 95% or more and an etching rate of 25 Å / min. Hereinafter, in particular, 15 kg / min. In the following, good corrosion resistance of a particle generation amount of 15/8 inch wafers, particularly 10/8 inch wafers was shown.
[0039]
(Example 2)
After performing CIP treatment at a pressure of 3 ton / cm 2 using CaF 2 powder having an average particle size of 10 μm and a metal element content (impurity amount) of 83 ppm other than alkaline earth metal in the sintered body, in an Ar atmosphere, Atmospheric firing (PLS) was performed at a firing temperature of 1100 ° C. The obtained sample was evaluated in the same manner as in Example 1. As a result, the relative density was 95%, the average crystal grain size was 13 μm, the etching rate was 22 Å / min. The particle generation amount of 15/8 inch wafers showed good corrosion resistance.
[0040]
【The invention's effect】
As described above in detail, according to the present invention, at least one alkaline earth metal selected from the group consisting of Mg, Ca, Sr and Ba is used as a member exposed to fluorine-based and chlorine-based corrosive gas or plasma. By using a sintered body made of fluoride and having a total amount of metal elements other than the alkaline earth metal of 100 ppm or less in terms of metal, an average particle size of 30 μm or less, and a relative density of 95% or more, Because it has long-term durability in high-density fluorine-based and chlorine-based corrosive atmospheres, does not generate contamination and particles, and maintains mechanical strength as a large component, it is especially suitable for semiconductor manufacturing equipment, especially plasma. By using it as a member such as jigs such as the inner wall member of the processing equipment and the support to support the object to be processed, it improves the yield of semiconductor manufacturing and high quality It can be manufactured of a semiconductor device.
Claims (4)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26044698A JP3618048B2 (en) | 1998-09-14 | 1998-09-14 | Components for semiconductor manufacturing equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26044698A JP3618048B2 (en) | 1998-09-14 | 1998-09-14 | Components for semiconductor manufacturing equipment |
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| Publication Number | Publication Date |
|---|---|
| JP2000086344A JP2000086344A (en) | 2000-03-28 |
| JP3618048B2 true JP3618048B2 (en) | 2005-02-09 |
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| Application Number | Title | Priority Date | Filing Date |
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| JP26044698A Expired - Fee Related JP3618048B2 (en) | 1998-09-14 | 1998-09-14 | Components for semiconductor manufacturing equipment |
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| US9580331B2 (en) | 2011-05-27 | 2017-02-28 | Nikon Corporation | CaF2 polycrystalline body, focus ring, plasma processing apparatus, and method for producing CaF2 polycrystalline body |
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| US6780787B2 (en) * | 2002-03-21 | 2004-08-24 | Lam Research Corporation | Low contamination components for semiconductor processing apparatus and methods for making components |
| JP5185213B2 (en) * | 2009-06-16 | 2013-04-17 | 株式会社大興製作所 | Method for producing plasma-resistant fluoride sintered body |
| JP5578507B2 (en) * | 2009-11-05 | 2014-08-27 | 株式会社大興製作所 | CaF2-MgF2 binary sintered body and method for producing plasma-resistant fluoride sintered body |
| JP5711511B2 (en) * | 2010-12-09 | 2015-04-30 | 株式会社大興製作所 | CaF2-MgF2 binary sintered body and method for producing plasma-resistant fluoride sintered body |
| JP5577287B2 (en) * | 2011-03-30 | 2014-08-20 | 日本碍子株式会社 | Magnesium fluoride sintered body, manufacturing method thereof, and member for semiconductor manufacturing apparatus |
| CN104428271B (en) | 2012-07-05 | 2017-03-08 | 株式会社尼康 | Polycrystalline CaF2Component, for plasma processing apparatus component, plasma processing apparatus and focusing ring manufacture method |
| WO2015005006A1 (en) | 2013-07-08 | 2015-01-15 | 国立大学法人筑波大学 | Fluoride sintered compact for neutron moderator, and method for producing said fluoride sintered compact |
| US9789335B2 (en) | 2014-09-24 | 2017-10-17 | Techno Eye Corporation | MgF2—CaF2 binary system sintered body for radiation moderator and method for producing the same |
| EP3885329A1 (en) | 2014-12-26 | 2021-09-29 | University of Tsukuba | Mgf2 sintered body for radiation moderator |
| KR101924308B1 (en) * | 2015-07-21 | 2018-11-30 | 니폰게이긴조쿠가부시키가이샤 | Magnesium sintered body, method of producing magnesium sintered body, method of producing neutron moderator and neutron moderator |
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1998
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9580331B2 (en) | 2011-05-27 | 2017-02-28 | Nikon Corporation | CaF2 polycrystalline body, focus ring, plasma processing apparatus, and method for producing CaF2 polycrystalline body |
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| JP2000086344A (en) | 2000-03-28 |
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