JP2008294016A - Ceramics substrate and semiconductor manufacturing apparatus provided with the same - Google Patents

Ceramics substrate and semiconductor manufacturing apparatus provided with the same Download PDF

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JP2008294016A
JP2008294016A JP2007134930A JP2007134930A JP2008294016A JP 2008294016 A JP2008294016 A JP 2008294016A JP 2007134930 A JP2007134930 A JP 2007134930A JP 2007134930 A JP2007134930 A JP 2007134930A JP 2008294016 A JP2008294016 A JP 2008294016A
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ceramic substrate
electrode
electrode member
cover member
substrate
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Masuhiro Natsuhara
益宏 夏原
Tomoyuki Awazu
知之 粟津
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Sumitomo Electric Industries Ltd
SEI Hybrid KK
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Sumitomo Electric Industries Ltd
SEI Hybrid KK
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<P>PROBLEM TO BE SOLVED: To provide a ceramic substrate for a semiconductor manufacturing apparatus, especially a shower substrate, wherein the connection structure of electrodes is greatly improved so as to enhance throughput of a semiconductor process. <P>SOLUTION: The ceramics substrate 1 is arranged within the chamber of a semiconductor manufacturing apparatus, and a conductor 2 is embedded inside itself. It is provided with an electrode member 3 for external terminal connection that is connected with the conductor 2, a conductive cover member 4 that is connected with the electrode member 3 and covers the same, and an O-ring 5 that prevents the electrode member 3 covered with the cover member 4 from being exposed to an atmosphere within the chamber. The electrode member 3 and the ceramics substrate 1, and the electrode member 3 and the cover member 4 are mechanically joined with each other by screws, respectively. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は、CVD装置、プラズマCVD装置、エッチング装置、プラズマエッチング装置等の半導体製造装置に使用されるセラミックス基板に関し、特に腐食性ガスにさらされるセラミックス基板内埋設した導電体の給電構造に関するものである。   The present invention relates to a ceramic substrate used in a semiconductor manufacturing apparatus such as a CVD apparatus, a plasma CVD apparatus, an etching apparatus, and a plasma etching apparatus, and more particularly to a power feeding structure for a conductor embedded in a ceramic substrate exposed to a corrosive gas. is there.

半導体ウエハの表面をエッチングし又はその表面上に膜を形成する際には、半導体ウエハをラックに多数個保持して、バッチ式でエッチング用や膜形成用のガスを流し、必要に応じてヒーターで加熱する(ホットウォール式)という手法が用いられてきた。   When etching the surface of a semiconductor wafer or forming a film on the surface, a large number of semiconductor wafers are held in a rack, a gas for etching or film formation is flowed in a batch system, and a heater is used as necessary. The method of heating with (hot wall type) has been used.

しかし、近年では、半導体装置の高集積化や高速化の要求が厳しくなるに伴い、半導体製造装置内の場所による温度やガスの流れの不均一に起因して、エッチングや形成される膜の品質がばらつくことが問題になってきた。そこで、複数のエッチング装置や膜形成装置を並べて、それらの装置間にローダーを用いて半導体ウエハを1枚ずつ自動送りして処理する枚葉式に切換わりつつある。   However, in recent years, as the demand for higher integration and higher speed of semiconductor devices has become stricter, the quality of etching and formed films due to uneven temperature and gas flow depending on the location in the semiconductor manufacturing equipment. Dispersion has become a problem. In view of this, a plurality of etching apparatuses and film forming apparatuses are arranged side by side, and a wafer load type is being switched in which semiconductor wafers are automatically fed one by one using a loader between these apparatuses.

枚葉式の半導体製造装置では、半導体ウエハをセラミックス製や金属製のウエハ保持体の表面上に載置し、ウエハ保持体に内蔵した電極に電圧を付加して静電力でチャックすること等によって半導体ウエハを保持する。保持された半導体ウエハは、CVD、プラズマCVD、エッチング、プラズマエッチング等における膜形成速度やエッチング速度を調整するために、その表面温度が厳密に制御される。その温度制御のために、ウエハ保持体に内蔵したヒーターによりウエハ保持体を加熱して、半導体ウエハを加熱するようになっている。   In a single wafer type semiconductor manufacturing apparatus, a semiconductor wafer is placed on the surface of a ceramic or metal wafer holder, a voltage is applied to an electrode built in the wafer holder and chucked by an electrostatic force, etc. A semiconductor wafer is held. The surface temperature of the held semiconductor wafer is strictly controlled in order to adjust the film formation rate and etching rate in CVD, plasma CVD, etching, plasma etching, and the like. In order to control the temperature, the wafer holder is heated by a heater built in the wafer holder to heat the semiconductor wafer.

また、半導体製造装置のチャンバーに取付けたパイプから反応ガスを単に送り込むだけでは、ガスが直接吹き込まれる箇所と間接的に吹き込まれる箇所との間でガスの流れが不均一になり、半導体ウエハの表面において反応ガスの濃度がばらつくことになる。その結果、半導体ウエハの表面において、膜形成やエッチングを均一に制御することが困難になる。   In addition, if the reaction gas is simply fed from a pipe attached to the chamber of the semiconductor manufacturing apparatus, the gas flow becomes uneven between the location where the gas is directly blown and the location where the gas is blown indirectly. In this case, the concentration of the reaction gas varies. As a result, it becomes difficult to uniformly control film formation and etching on the surface of the semiconductor wafer.

そこで、半導体ウエハの表面上においてガスの吹き込みを均一にし、反応ガスの濃度を一定にするために、板状の基材に多数の貫通孔を形成したシャワー基板を半導体ウエハの直上の位置に設置する方法が採用されている。この方法によれば、ガスがシャワー状に吹き出し、半導体ウエハの表面上においてできるだけ均一なガス濃度が得られる。   Therefore, in order to make the gas blow uniform on the surface of the semiconductor wafer and to keep the concentration of the reaction gas constant, a shower substrate with a large number of through holes formed in a plate-like substrate is installed at a position directly above the semiconductor wafer. The method to do is adopted. According to this method, gas blows out in a shower shape, and a gas concentration as uniform as possible can be obtained on the surface of the semiconductor wafer.

例えば特許第3654142号公報には、セラミックス製のガスシャワー体が開示されている。この公報によれば、セラミックス基板の厚みを1〜5mmとし、導電体を印刷にて形成している。そして、このガスシャワー体を用いることで、均一なガスの流れが形成できるとしている。
特許第3654142号公報
For example, Japanese Patent No. 3654142 discloses a ceramic gas shower unit. According to this publication, the thickness of the ceramic substrate is 1 to 5 mm, and the conductor is formed by printing. By using this gas shower body, a uniform gas flow can be formed.
Japanese Patent No. 3654142

近年の半導体プレセスでは、コストをできるだけ低減するために、スループットの向上が求められている。シャワー基板を使用する枚葉式のCVD装置、エッチング装置、プラズマCVD装置などにおいても同様である。特に成膜装置においては、成膜時にウエハ以外の部分にも必然的に膜形成されてしまうため、この膜が場合によっては剥がれ落ち、パーティクルとなってウエハに付着してしまい、歩留まりを低下させる原因となる。   In recent semiconductor processes, an improvement in throughput is required in order to reduce the cost as much as possible. The same applies to a single wafer type CVD apparatus, an etching apparatus, a plasma CVD apparatus or the like that uses a shower substrate. In particular, in a film forming apparatus, a film is inevitably formed on a portion other than the wafer at the time of film formation, so that this film may be peeled off in some cases and attached to the wafer as particles, thereby reducing the yield. Cause.

そこで、枚葉式の成膜装置では、所定数量のウエハの処理を終えた段階で、ウエハ以外に付着した膜を除去するためのクリーニングを実施する。このクリーニングの際には、チャンバー内に付着した膜を分解、除去できるクリーニングガスを流し、必要に応じてチャンバー内を加熱する。このとき使用するクリーニングガスは、クリーニング時間を短くするために、腐食性が非常に強いガス、例えばCF、NF、ClFなどのフッ素系のガスがよく使用される。 In view of this, in a single wafer type film forming apparatus, cleaning is performed to remove a film adhering to a portion other than the wafer when a predetermined number of wafers have been processed. In this cleaning, a cleaning gas capable of decomposing and removing the film attached in the chamber is flowed, and the inside of the chamber is heated as necessary. As the cleaning gas used at this time, in order to shorten the cleaning time, a highly corrosive gas such as a fluorine-based gas such as CF 4 , NF 3 , or ClF 3 is often used.

しかし、チャンバー内に配置して使用されるセラミックス基板においては、セラミックス基板内に埋設された導電体に外部から給電するための電極の接続構造が、セラミックス基板の熱膨張係数と電極接続部の熱膨張係数との差が大きいため、耐食性について十分信頼性のある接続構造となっていない。特にシャワー基板では、耐食性の高いセラミックスも用いられてきているが、シャワー基板に設置されるヒーター回路や高周波発生用のRF回路の電極接続構造に対する検討が十分ではないため、一部の分野にしか採用されていないのが現状である。   However, in a ceramic substrate used by being placed in a chamber, the electrode connection structure for supplying power from the outside to the conductor embedded in the ceramic substrate has a thermal expansion coefficient of the ceramic substrate and the heat of the electrode connection portion. Since the difference from the expansion coefficient is large, the connection structure is not sufficiently reliable for corrosion resistance. Especially for shower boards, ceramics with high corrosion resistance have also been used. However, the electrode connection structure of the heater circuit installed on the shower board and the RF circuit for high frequency generation is not sufficiently studied. The current situation is that it has not been adopted.

本願は、このような従来の事情に鑑み、耐食性が高いセラミックスからなる基板、特にシャワー基板について、半導体プロセスのスループットを向上させることができるように、その電極の接続構造を大幅に改善することを目的とするものである。   In view of such conventional circumstances, the present application is to greatly improve the electrode connection structure of a substrate made of ceramics having high corrosion resistance, particularly a shower substrate, so that the throughput of the semiconductor process can be improved. It is the purpose.

上記目的を達成するため、本発明が提供するセラミックス基板は、半導体製造装置のチャンバー内に設置され、内部に導電体を埋設したセラミックス基板であって、該導電体に接続された外部端子接続用の電極部材と、電極部材に接続され且つ電極部材を被覆する導電性のカバー部材と、カバー部材で被覆されている電極部材をチャンバー内雰囲気から遮断する封止構造とを有することを特徴とするものである。   In order to achieve the above object, a ceramic substrate provided by the present invention is a ceramic substrate that is installed in a chamber of a semiconductor manufacturing apparatus and has a conductor embedded therein, and for connecting an external terminal connected to the conductor. And a conductive cover member connected to the electrode member and covering the electrode member, and a sealing structure for shielding the electrode member covered with the cover member from the atmosphere in the chamber. Is.

上記本発明のセラミックス基板においては、前記電極部材と前記セラミックス基板とが機械的に接続されているか、あるいは、前記電極部材と前記カバー部材とが機械的に接続されている。   In the ceramic substrate of the present invention, the electrode member and the ceramic substrate are mechanically connected, or the electrode member and the cover member are mechanically connected.

また、上記本発明のセラミックス基板においては、前記電極部材と前記カバー部材の間に応力緩和部材を有するか、あるいは、前記電極部材と前記セラミックス基板の間に応力緩和部材を有している。   In the ceramic substrate of the present invention, a stress relaxation member is provided between the electrode member and the cover member, or a stress relaxation member is provided between the electrode member and the ceramic substrate.

上記本発明のセラミックス基板において、前記応力緩和部材は、前記電極部材と前記カバー部材又は前記セラミックス基板と機械的に結合されていることが好ましい。また、前記応力緩和部材はヘリサートであることが好ましい。   In the ceramic substrate of the present invention, it is preferable that the stress relaxation member is mechanically coupled to the electrode member and the cover member or the ceramic substrate. The stress relaxation member is preferably a helicate.

上記本発明のセラミックス基板においては、前記応力緩和部材が円筒体であって、該円筒体の内周面に前記電極部材と接続するための雌ネジを有し、且つ外周面に前記カバー部材又はセラミックス基板と接続するための雄ネジを有することができる。   In the ceramic substrate of the present invention, the stress relaxation member is a cylindrical body, and has an internal thread for connecting to the electrode member on an inner peripheral surface of the cylindrical body, and the cover member or A male screw for connecting to the ceramic substrate can be provided.

また、上記本発明のセラミックス基板においては、前記セラミックス基板内に接合された金属部材を備え、該金属部材を貫通して雌ネジが形成され、その雌ネジに前記電極部材に設けた雄ネジが螺合貫通していることができる。   Further, the ceramic substrate of the present invention includes a metal member joined in the ceramic substrate, a female screw is formed through the metal member, and a male screw provided on the electrode member is formed on the female screw. It can be threaded through.

更に、上記本発明のセラミックス基板において、前記封止構造が、前記セラミックス基板と前記カバー部材の間に装着したO−リングであることが好ましい。この場合、前記O−リングと接触する前記セラミックス基板及び前記カバー部材の表面粗さが、Ra≦2.0μmであることが好ましい。   Furthermore, in the ceramic substrate of the present invention, it is preferable that the sealing structure is an O-ring mounted between the ceramic substrate and the cover member. In this case, it is preferable that the surface roughness of the ceramic substrate and the cover member in contact with the O-ring is Ra ≦ 2.0 μm.

本発明は、また、上記した本発明によるセラミックス基板として、複数の貫通孔を有するシャワー基板を提供するものである。更に、本発明は、上記した本発明によるセラミックス基板又はシャワー基板が搭載されていることを特徴とする半導体製造装置を提供するものである。   The present invention also provides a shower substrate having a plurality of through holes as the ceramic substrate according to the present invention. Furthermore, the present invention provides a semiconductor manufacturing apparatus on which the ceramic substrate or shower substrate according to the present invention described above is mounted.

本発明によれば、耐食性が高いセラミックスからなる基板であって、その基板内に埋設された導電体に外部から給電するための電極の接続構造を改善し、セラミックスの熱膨張係数と電極接続部の熱膨張係数との差が大きくても、腐食性が強いガスに対して十分な信頼性を有するセラミックス基板、特にシャワー基板を提供することができる。従って、本発明のセラミックス基板を搭載した半導体製造装置を使用することによって、半導体プロセスのスループットを向上させることができる。   According to the present invention, there is provided a substrate made of ceramics having high corrosion resistance, the electrode connecting structure for supplying power from the outside to the conductor embedded in the substrate is improved, and the thermal expansion coefficient of the ceramics and the electrode connecting portion are improved. Even if the difference from the coefficient of thermal expansion is large, it is possible to provide a ceramic substrate, particularly a shower substrate, having sufficient reliability against a highly corrosive gas. Therefore, the throughput of the semiconductor process can be improved by using the semiconductor manufacturing apparatus equipped with the ceramic substrate of the present invention.

本発明のセラミックス基板は、内部に導電体が埋設されている。導電体の機能としてはヒーターや高周波発生用電極(RF電極)が挙げられ、これらの内のどちらか一方ないしは両方を具備することができる。かかる導電体を埋設するセラミックス基板として、シャワー基板を例にして以下に説明する。   The ceramic substrate of the present invention has a conductor embedded therein. Examples of the function of the conductor include a heater and an electrode for high frequency generation (RF electrode), and any one or both of them can be provided. As a ceramic substrate in which such a conductor is embedded, a shower substrate will be described below as an example.

シャワー基板に埋設する導電体がヒーターである場合、シャワー基板の役割はウエハに対して反応ガスを均一に分散すること以外に、均一な温度にガスを予熱することが挙げられる。また、シャワー基板に形成されたガスの通り道である貫通孔が塞がらないように、シャワー基板自体を加熱する意味合いもある。また、導電体がRF電極である場合は、シャワー基板の下部に設置された下部電極との間に、例えば13.56MHzの高周波を印加してプラズマを発生させ、比較的低温でウエハ上に成膜することができる。   When the conductor embedded in the shower substrate is a heater, the role of the shower substrate is to preheat the gas to a uniform temperature in addition to uniformly dispersing the reaction gas to the wafer. In addition, there is also a meaning that the shower substrate itself is heated so that the through hole, which is a gas passage formed in the shower substrate, is not blocked. In the case where the conductor is an RF electrode, plasma is generated by applying a high frequency of, for example, 13.56 MHz between the lower electrode installed at the lower part of the shower substrate, and is formed on the wafer at a relatively low temperature. Can be membrane.

このような導電体を有するシャワー基板において、導電体に給電するための電極の接続構造としては、まず、基板内部の導電体に外部端子接続用の電極部材を接続する。接続方法としては、特に制約はなく、ロウ材などで導電体と電極部材を接合する方法、あるいはネジなどの機械的な手段で接続する方法が挙げられる。しかし、いずれの方法においても、セラミックス基板と熱膨張係数が比較的近いことが必要であるため、好ましい電極部材材料としてはタングステン、モリブデン、コバール、ステンレス、ニッケルなどを主成分とするものが好ましい。更に好ましくは、セラミックス基板と電極部材の熱膨張係数差が5.0×10−6/K以下であることが好ましい。 In a shower substrate having such a conductor, as an electrode connection structure for supplying power to the conductor, first, an electrode member for connecting an external terminal is connected to the conductor inside the substrate. The connection method is not particularly limited, and examples thereof include a method of joining a conductor and an electrode member with a brazing material or the like, or a method of connecting with a mechanical means such as a screw. However, in any of the methods, since the thermal expansion coefficient needs to be relatively close to the ceramic substrate, a preferable electrode member material is preferably composed mainly of tungsten, molybdenum, kovar, stainless steel, nickel or the like. More preferably, the difference in thermal expansion coefficient between the ceramic substrate and the electrode member is 5.0 × 10 −6 / K or less.

上記した電極部材は、半導体プロセスで使用されるガスに対して耐食性がほとんどないため、このまま使用することはできない。そこで、本発明では、この電極部材を覆うカバー部材を新たに設置する。カバー部材としては、導電性があり、比較的腐食性が強く、半導体プロセスに対してコンタミネーションなどの影響を与えない物質から選ばれる。具体的には、ニッケル、アルミニウム、ステンレスなどを挙げることができる。そして、このカバー部材とセラミックス基板とを封止して、電極部材がチャンバー内に露出しないようにする。この封止構造としては、使用温度にもよるが、使用温度が300℃程度までなら耐熱性の高いフッ素系のO−リングを使用することができる。   The electrode member described above cannot be used as it is because it has little corrosion resistance to the gas used in the semiconductor process. Therefore, in the present invention, a cover member that covers this electrode member is newly installed. The cover member is selected from materials that are conductive, relatively corrosive, and do not affect the semiconductor process such as contamination. Specific examples include nickel, aluminum, and stainless steel. The cover member and the ceramic substrate are sealed so that the electrode member is not exposed in the chamber. As this sealing structure, although depending on the operating temperature, if the operating temperature is up to about 300 ° C., a fluorine-based O-ring having high heat resistance can be used.

このとき、O−リングと接触するカバー部材及びセラミックス基板の各接触面の表面粗さは、Ra≦2.0μmであることが好ましい。これよりも表面粗さが粗いと、O−リングとセラミックス又はカバー部材の間から腐食性のガスが侵入し、電極部材が腐食されることがあるため好ましくない。電極部材が腐食されると電気抵抗値が高くなり、更に腐食が進めば導通不良を起こす。特にRa≦1.0μmであれば、封止性がより一層向上し、電極部材自体の変色もほとんどなくなるため、信頼性の面で特に好ましい。   At this time, the surface roughness of each contact surface of the cover member and the ceramic substrate in contact with the O-ring is preferably Ra ≦ 2.0 μm. If the surface roughness is larger than this, a corrosive gas may enter from between the O-ring and the ceramics or the cover member, and the electrode member may be corroded. When the electrode member is corroded, the electric resistance value becomes high, and when the corrosion further progresses, conduction failure occurs. In particular, Ra ≦ 1.0 μm is particularly preferable from the viewpoint of reliability because the sealing property is further improved and the discoloration of the electrode member itself is almost eliminated.

このような電極接続構造の代表的な具体例を図1に示す。この電極接続構造では、セラミックス基板1の内部に埋設された導電体2を所定の深さ位置までスルーホール等で上部に伸ばしておき、そこに電極部材3を例えばネジ止めのような手段で機械的に接続する。即ち、電極部材3の外周面に設けた雄ネジを、セラミックス基板1内に設けた雌ネジと螺合して接続する。尚、この電極部材3は、セラミックス基板1のウエハ載置面とは反対側の面に露出させる。   A typical example of such an electrode connection structure is shown in FIG. In this electrode connection structure, the conductor 2 embedded in the ceramic substrate 1 is extended upward by a through hole or the like to a predetermined depth position, and the electrode member 3 is mechanically moved there by means such as screwing. Connect. That is, a male screw provided on the outer peripheral surface of the electrode member 3 is screwed and connected to a female screw provided in the ceramic substrate 1. The electrode member 3 is exposed on the surface of the ceramic substrate 1 opposite to the wafer mounting surface.

このままの状態では、使用する腐食性ガスによって電極部材3が腐食されるため、導電性のカバー部材4を電極部材3に対して、例えばネジ止めのような手段で機械的に接続して電極部材3覆う。即ち、カバー部材4内に設けた雌ネジを、電極部材3の外周面に設けた雄ネジと螺合して接続する。そして、セラミックス基板1とカバー部材4の間をO−リング5などの封止部材で封止すれば、比較的簡単な構造で電極部材3を封止して、耐久性の高い電極接続構造とすることができる。   In this state, since the electrode member 3 is corroded by the corrosive gas used, the conductive cover member 4 is mechanically connected to the electrode member 3 by means such as screwing, for example. 3 Cover. That is, the female screw provided in the cover member 4 is screwed and connected with the male screw provided on the outer peripheral surface of the electrode member 3. If the gap between the ceramic substrate 1 and the cover member 4 is sealed with a sealing member such as an O-ring 5, the electrode member 3 is sealed with a relatively simple structure, and a highly durable electrode connection structure is obtained. can do.

上記の電極接続構造においては、セラミックス基板1内の導電体2と、電極部材3と、導電性のカバー部材4とが電気的に接続されている。従って、カバー部材4に外部端子の給電部6を固定ネジ7で接続して、簡単に給電することができるのである。また、カバー部材4はセラミックス基板1には直接接続されていないため、カバー部材4としてセラミックス基板1に対して非常に熱膨張係数が大きいニッケル、アルミニウム、ステンレスなどを使用することができる。特に、これらの金属は上記のような腐食性ガスに対する耐食性が比較的強い材料であるため、信頼性の高い電極接続構造とすることができる。   In the above electrode connection structure, the conductor 2 in the ceramic substrate 1, the electrode member 3, and the conductive cover member 4 are electrically connected. Therefore, power can be easily supplied by connecting the power supply portion 6 of the external terminal to the cover member 4 with the fixing screw 7. Further, since the cover member 4 is not directly connected to the ceramic substrate 1, nickel, aluminum, stainless steel or the like having a very large thermal expansion coefficient with respect to the ceramic substrate 1 can be used as the cover member 4. In particular, since these metals are materials having relatively strong corrosion resistance against the corrosive gas as described above, a highly reliable electrode connection structure can be obtained.

電極部材とセラミックス基板との接続方法としては、ロウ付けなどの接合も採用することができるが、電極部材とセラミックス基板との間にどうしても熱膨張係数差が存在するため、機械的な接続方法が好ましい。機械的な接続方法としては、上記したネジによる螺合、即ち電極部材の外周面に設けた雄ネジとセラミックス基板内に設けた雌ネジとの螺合のほか、バネなどで電極部材を押さえ付ける方法などを挙げることができる。   As a method for connecting the electrode member and the ceramic substrate, joining such as brazing can also be adopted, but since there is a difference in thermal expansion coefficient between the electrode member and the ceramic substrate, there is a mechanical connection method. preferable. As a mechanical connection method, the above-described screwing, that is, the male screw provided on the outer peripheral surface of the electrode member and the female screw provided in the ceramic substrate, and the electrode member is pressed by a spring or the like. The method etc. can be mentioned.

また、電極部材とセラミックス基板は熱膨張係数が比較的一致しているが、カバー部材として例えばアルミニウムなどを使用し、電極部材としてタングステンやモリブデン、コバールなどを使用すると、電極部材とカバー部材との間の熱膨張係数は非常に大きなものとなる。このため、ロウ付けなどの手法で両者を接合すると温度サイクルなどによって外れることがあるため、機械的な手段で接続することが好ましい。この場合の機械的手段としては、上記と同様に、例えばネジ止めやバネなどの手段で接続することが挙げられる。   In addition, the thermal expansion coefficients of the electrode member and the ceramic substrate are relatively the same. However, for example, when aluminum or the like is used as the cover member and tungsten, molybdenum, Kovar, or the like is used as the electrode member, the electrode member and the cover member The coefficient of thermal expansion in between is very large. For this reason, when both are joined by a technique such as brazing, they may come off due to a temperature cycle or the like, and therefore it is preferable to connect them by mechanical means. Examples of mechanical means in this case include connection by means such as screwing and springs as described above.

上記したネジ止めやバネなどの機械的な接続手段の中では、特にネジ止めが好適である。本発明のセラミックス基板ように温度が加わる部材では、バネによる接続の場合、バネ自身が高温時にバネ性を喪失することがあり、それによって電気的な接続が不安定になることがあるため、特に200℃を超える高温で使用する場合にはネジで接続することが好ましい。ネジによる接続は、各部材間に熱膨張係数差が存在していても、雄ネジと雌ネジの間には若干のクリアランスが存在するために、ある程度の熱膨張量の差を吸収できると共に、バネのように電気的な接続に対する不安定さが少ないために好ましい。   Of the above-described mechanical connection means such as screwing and springs, screwing is particularly suitable. In the case where the member is subjected to temperature like the ceramic substrate of the present invention, in the case of connection by a spring, the spring itself may lose its spring property at a high temperature, and thereby the electrical connection may become unstable. When using at a high temperature exceeding 200 ° C., it is preferable to connect with a screw. Even if there is a difference in thermal expansion coefficient between each member, the connection with screws can absorb a certain amount of thermal expansion amount because there is some clearance between the male screw and the female screw. This is preferable because there is little instability with respect to an electrical connection like a spring.

上記した本発明の電極接続構造においては、カバー部材と電極部材との間に応力緩和材を設けることができる。例えば、セラミックス基板の電極部付近が高温になると、当然のことながらカバー部材も高温になる。このとき、例えばカバー部材の方が電極部材よりも熱膨張係数が大きい場合、カバー部材が電極部材を上方に持ち上げるような力が働く。従って、電極部材とセラミックス基板の間の熱膨張係数差が小さくても、電極部材とセラミックス基板のネジ止め部分、即ちネジ山にも上向きの力が働くことになる。そして、この上向きの力が大きければ大きいほど、ネジ山に加わる応力も大きくなるため、場合によってはネジ山が破損する危険がある。   In the electrode connection structure of the present invention described above, a stress relaxation material can be provided between the cover member and the electrode member. For example, when the vicinity of the electrode portion of the ceramic substrate becomes high temperature, the cover member naturally becomes high temperature. At this time, for example, when the cover member has a larger coefficient of thermal expansion than the electrode member, a force is exerted so that the cover member lifts the electrode member upward. Therefore, even if the difference in thermal expansion coefficient between the electrode member and the ceramic substrate is small, an upward force is also applied to the screwed portion of the electrode member and the ceramic substrate, that is, the screw thread. And the greater the upward force, the greater the stress applied to the thread, and there is a risk of damage to the thread in some cases.

このため、電極部材とカバー部材との間に大きな熱膨張係数差が存在する場合や、セラミックス基板の使用温度が高い場合には、セラミックス基板に加わる応力を低減するために、カバー部材と電極部材の間に応力緩和部材を挿入することが好ましい。また、電極部材とセラミックス基板の間に応力緩和部材を設置することによっても、セラミックス基板に加わる応力を低減することができる。   For this reason, when there is a large difference in thermal expansion coefficient between the electrode member and the cover member, or when the use temperature of the ceramic substrate is high, in order to reduce the stress applied to the ceramic substrate, the cover member and the electrode member It is preferable to insert a stress relaxation member between them. Also, the stress applied to the ceramic substrate can be reduced by installing a stress relaxation member between the electrode member and the ceramic substrate.

具体的には、例えば図2に示すように、カバー部材4と電極部材3の間に、円筒体の内周面に雌ネジを有し且つ外周面に雄ネジを有する応力緩和部材8を配置し、カバー部材4及び電極部材3と螺合することが可能である。このような応力緩和部材8を配置した構造においては、電極部材3とカバー部材4の熱膨張量の差を、応力緩和部材8の変形や、それぞれのネジ山間のクリアランスによって吸収することができるため、セラミックス基板1側に加わる応力を低減することができる。   Specifically, for example, as shown in FIG. 2, a stress relaxation member 8 having a female screw on the inner peripheral surface of the cylindrical body and a male screw on the outer peripheral surface is disposed between the cover member 4 and the electrode member 3. The cover member 4 and the electrode member 3 can be screwed together. In such a structure in which the stress relaxation member 8 is disposed, the difference in thermal expansion between the electrode member 3 and the cover member 4 can be absorbed by deformation of the stress relaxation member 8 and clearance between the respective screw threads. The stress applied to the ceramic substrate 1 side can be reduced.

上記応力緩和部材は、導電性を有する材料であって、比較的変形能の大きな軟質金属、例えば、アルミニウム、銅、ニッケル、銀、金などが好ましい。また、主に応力緩和部材の変形能によって応力を吸収する場合には、応力緩和部材の厚みをできるだけ薄くすることが必要である。例えば、応力緩和部材の外側のネジ山、即ちカバー部材と螺合されるネジ山をM6とし、内側の雌ネジ、即ち電極部材と螺合されるネジ山をM3とすれば、比較的薄い厚みの応力緩和部材でカバー部材と電極部材を接続することができる。この場合の応力緩和部材のネジ山は、設置する寸法に応じて変えることができ、外ネジがM5で内ネジがM2などあらゆる組み合わせが考えられる。   The stress relieving member is a conductive material, and is preferably a soft metal having a relatively large deformability, such as aluminum, copper, nickel, silver, or gold. Further, when stress is absorbed mainly by the deformability of the stress relaxation member, it is necessary to make the thickness of the stress relaxation member as thin as possible. For example, if the outer thread of the stress relaxation member, that is, the screw thread to be screwed with the cover member is M6, and the inner female screw, ie, the screw thread to be screwed with the electrode member, is M3, the thickness is relatively thin. The cover member and the electrode member can be connected by the stress relaxation member. In this case, the thread of the stress relieving member can be changed according to the dimension to be installed, and any combination including an outer screw M5 and an inner screw M2 is conceivable.

また、カバー部材と電極部材の中間の熱膨張係数を有する応力緩和部材を挿入することもできる。この場合の応力緩和部材の材質としては、熱膨張係数がカバー部材と電極部材の中間の熱膨張係数を有しておれば特に問題はなく、ニッケルやステンレス、あるいはアルミニウムと炭化ケイ素又はシリコンの複合体、シリコンと炭化ケイ素の複合体などを挙げることができる。このように電極部材とカバー部材の間に応力緩和部材を設けることで、セラミックス基板に加わる応力を低減し、電極接続構造に対する信頼性を向上させることができる。   It is also possible to insert a stress relaxation member having a thermal expansion coefficient intermediate between the cover member and the electrode member. The material of the stress relaxation member in this case is not particularly problematic as long as the coefficient of thermal expansion has an intermediate coefficient of thermal expansion between the cover member and the electrode member, and is a combination of nickel, stainless steel, or aluminum and silicon carbide or silicon. And a composite of silicon and silicon carbide. Thus, by providing a stress relaxation member between an electrode member and a cover member, the stress added to a ceramic substrate can be reduced and the reliability with respect to an electrode connection structure can be improved.

上記応力緩和部材は、電極部材とカバー部材又は電極部材とセラミックス基板に機械的に結合されていることが好ましい。例えば、上記した図2に示すように内周面と外周面にネジ山を有する円筒体のほか、ヘリサートを用いることができる。例えば図3に示すように、ヘリサート9は電極部材3の外周面の雄ネジのネジ山とセラミックス基板1の間に挿入され、カバー部材4が上方に伸びようとするときに、その熱膨張を吸収することによって、セラミックス基板1や電極部材3に働く応力を緩和することができる。   The stress relieving member is preferably mechanically coupled to the electrode member and the cover member or the electrode member and the ceramic substrate. For example, a helicate can be used in addition to a cylindrical body having threads on the inner and outer peripheral surfaces as shown in FIG. For example, as shown in FIG. 3, the helisert 9 is inserted between the thread of the male screw on the outer peripheral surface of the electrode member 3 and the ceramic substrate 1, and when the cover member 4 tries to extend upward, its thermal expansion occurs. By absorbing, the stress acting on the ceramic substrate 1 and the electrode member 3 can be relaxed.

また、カバー部材とセラミックス基板の間に、空隙を設けることも有効な手段である。例えば上述したようにカバー部材の温度が上昇したとき、カバー部材と電極部材の熱膨張量の差によって、電極部材を引っ張り上げようとする力が働く。このとき、セラミックス基板とカバー部材の間に空隙が存在すれば、カバー部材の熱膨張量を空隙で吸収することができるからである。   It is also effective to provide a gap between the cover member and the ceramic substrate. For example, when the temperature of the cover member rises as described above, a force for pulling up the electrode member works due to the difference in thermal expansion between the cover member and the electrode member. At this time, if there is a gap between the ceramic substrate and the cover member, the amount of thermal expansion of the cover member can be absorbed by the gap.

必要な空隙の量は、電極部材とカバー部材の接触長さ、即ちネジで螺合されている長さと、使用温度及び各部材の熱膨張係数差によって決まる。例えば、カバー部材がアルミニウム(熱膨張係数23×10−6/K)、電極部材がタングステン(熱膨張係数4.5×10−6/K)、螺合長さが5mm、使用温度が200℃の場合、必要な空隙量は5mm×(18.5×10−6)×200(℃)=0.0185mmとなり、約20μm程度の空隙が存在すれば、電極部材に加わる応力を大幅に低減することができる。 The amount of gap required depends on the contact length between the electrode member and the cover member, that is, the length screwed with the screw, the operating temperature, and the difference in thermal expansion coefficient between the members. For example, the cover member is aluminum (thermal expansion coefficient 23 × 10 −6 / K), the electrode member is tungsten (thermal expansion coefficient 4.5 × 10 −6 / K), the screwing length is 5 mm, and the operating temperature is 200 ° C. In this case, the required void amount is 5 mm × (18.5 × 10 −6 ) × 200 (° C.) = 0.0185 mm. If a void of about 20 μm exists, the stress applied to the electrode member is greatly reduced. be able to.

更に、応力を緩和する別の方法として、図4に示す構造がある。即ち、貫通して形成された雌ネジ部を有する金属部材10をセラミックス基板1内に接合し、この金属部材10の雌ネジに電極部材3の雄ネジを螺合して貫通させる。金属部材10としては、セラミックス基板1に対して比較的熱膨張係数の近い材質、例えば、コバール、モリブデン、タングステンなどが好ましい。また、金属部材10は、ガラスやロウ材などの接合層11により、セラミックス基板1に接合することができる。   Furthermore, as another method for relieving stress, there is a structure shown in FIG. That is, a metal member 10 having a female screw portion formed so as to penetrate is joined into the ceramic substrate 1, and the male screw of the electrode member 3 is screwed into the female screw of the metal member 10 so as to penetrate. As the metal member 10, a material having a coefficient of thermal expansion relatively close to that of the ceramic substrate 1, for example, kovar, molybdenum, tungsten, or the like is preferable. The metal member 10 can be bonded to the ceramic substrate 1 by a bonding layer 11 such as glass or brazing material.

上記した図4の接続構造によれば、例えば電極部材3に働く上向きの応力は、封止した金属部材10に伝えられ、セラミックス基板1との封止部に分散されて働くことになる。セラミックス基板1のネジ山が電極部材3のネジ山に直接接触している場合には、セラミックス基板1と電極部材3の接触部分に応力が集中してネジ山に比較的大きな応力が加わるが、この図4の接続構造によれば、O−リング5などの封止部材が応力緩和部材となり、応力を分散させる効果があるため好ましい。   According to the connection structure of FIG. 4 described above, for example, upward stress acting on the electrode member 3 is transmitted to the sealed metal member 10 and is distributed and acts on the sealing portion with the ceramic substrate 1. When the thread of the ceramic substrate 1 is in direct contact with the thread of the electrode member 3, stress is concentrated on the contact portion between the ceramic substrate 1 and the electrode member 3, and a relatively large stress is applied to the thread. The connection structure of FIG. 4 is preferable because a sealing member such as the O-ring 5 becomes a stress relaxation member and has an effect of dispersing stress.

本発明のセラミックス基板の材質に関しては、特に制約はなく、アルミナ、窒化ケイ素、炭化ケイ素、ムライト、窒化アルミニウムなど、各種のセラミックスを使用することができる。その中でも窒化アルミニウムやアルミナなどのセラミックスはフッ素系ガスに対する耐食性がケイ素を含むセラミックスよりも高いため好ましく、特に窒化アルミニウムは熱伝導率も高く熱衝撃に対しても強いため特に好ましい。   The material of the ceramic substrate of the present invention is not particularly limited, and various ceramics such as alumina, silicon nitride, silicon carbide, mullite, and aluminum nitride can be used. Among them, ceramics such as aluminum nitride and alumina are preferable because they have higher corrosion resistance to fluorine-based gases than ceramics containing silicon, and aluminum nitride is particularly preferable because it has high thermal conductivity and is strong against thermal shock.

また、カバー部材に関しては、フッ素系ガスに対する耐食性を考えると、アルミニウム、ニッケル、ステンレスが好ましい。これらの金属材料は、フッ素系ガスと反応して、それぞれフッ化アルミニウムやフッ化ニッケルを生成するが、これらの物質はフッ素系ガスに対して不動態の膜となるため、パーティクルの発生などを抑えることができるため特に好ましい。尚、アルミニウムやニッケルなどは、セラミックス基板と熱膨張係数がマッチングしないため直接には接続できないが、本発明によればカバー部材としてセラミックス基板に接続して信頼性の高い電極接続構造とすることができる。   Further, regarding the cover member, aluminum, nickel, and stainless steel are preferable in view of corrosion resistance against the fluorine-based gas. These metal materials react with fluorine-based gases to produce aluminum fluoride and nickel fluoride, respectively, but these materials are passive films with respect to fluorine-based gases. Since it can suppress, it is especially preferable. Aluminum and nickel cannot be directly connected because their thermal expansion coefficients do not match with the ceramic substrate. However, according to the present invention, the cover member can be connected to the ceramic substrate to provide a highly reliable electrode connection structure. it can.

導電体は、セラミックス基板中に埋設するか、セラミックスを主成分とする膜で被覆して、腐食性ガスなどのチャンバー内雰囲気に露出しないようにする必要がある。埋設する方法としては、セラミックスのグリーンシートに所定の導電パターンをスクリーン印刷などの手法で形成し、更にその上にグリーンシートをラミネートすることで埋設することができる。また、セラミックスの成形体をプレス成形などの手法で作製し、その成形体中に金属箔やコイルなどを埋設した後、ホットプレスなどの手法で焼成することで埋設することができる。更に、セラミックスの焼結体に、スクリーン印刷で導電体を形成し、その後接合剤を用いて別のセラミックス焼結体を接合することもできる。   The conductor needs to be embedded in a ceramic substrate or covered with a film containing ceramic as a main component so as not to be exposed to a chamber atmosphere such as corrosive gas. As a method of embedding, it is possible to embed by forming a predetermined conductive pattern on a ceramic green sheet by a technique such as screen printing and further laminating the green sheet thereon. Further, a ceramic molded body can be prepared by a technique such as press molding, and after embedding a metal foil, a coil, or the like in the molded body, it can be embedded by firing by a technique such as hot pressing. Furthermore, a conductor can be formed on a ceramic sintered body by screen printing, and then another ceramic sintered body can be bonded using a bonding agent.

尚、上記したセラミックスを主成分とする膜で導電体を被覆する方法としては、セラミックス焼結体上にスクリーン印刷等の手法で導電体を形成した後、セラミックスのペーストを塗布し、焼成することで被覆することができる。また、前記と同様にセラミックス基板上に導電体を形成した後、セラミックスの溶射などの方法で導電体を被覆することも可能である。   In addition, as a method of coating the conductor with the above-described film containing ceramic as a main component, the conductor is formed on the ceramic sintered body by a method such as screen printing, and then a ceramic paste is applied and fired. Can be coated. Moreover, after forming a conductor on a ceramic substrate in the same manner as described above, it is also possible to cover the conductor by a method such as ceramic spraying.

シャワー基板には、導電体として複数の電極を形成することができる。シャワー基板の電極の位置は、通常はガスの流れに影響を与えない外周部に近い部分に設置される。例えば、シャワー基板に設置する導電体が高周波発生用電極(RF電極)である場合、1箇所に電極を設置することも可能であるが、設置した導電体自身が有するインピーダンスによって電極から遠い部分と近い部分とでインピーダンスに違いが生じ、プラズマの発生強度にバラツキが生じることがある。   A plurality of electrodes can be formed as a conductor on the shower substrate. The position of the electrode of the shower substrate is usually set at a portion close to the outer periphery that does not affect the gas flow. For example, when the conductor to be installed on the shower substrate is an electrode for high frequency generation (RF electrode), it is possible to install the electrode in one place, but the part far from the electrode due to the impedance of the installed conductor itself There may be a difference in impedance between the close portions and the generation intensity of plasma may vary.

このため、複数の電極の位置は、ガスの流れに対して比較的影響の少ないシャワー基板の外周部の部分に、均等に配置することが好ましい。配置する個数としては特に制約はないが、4個以上が特に好ましく、6個以上が更に好ましい。このような配置にすることで、より均一にプラズマを発生させることができ、例えば成膜の際にウエハ上の膜厚分布をより均一にすることができる。   For this reason, it is preferable that the positions of the plurality of electrodes be evenly arranged on the outer peripheral portion of the shower substrate that has a relatively small influence on the gas flow. The number to be arranged is not particularly limited, but is preferably 4 or more, and more preferably 6 or more. With such an arrangement, plasma can be generated more uniformly, and for example, the film thickness distribution on the wafer can be made more uniform during film formation.

RF電極の材質としては、セラミックス基板に埋設するため、熱膨張がセラミックスに近いものが好ましい。例えば、タングステン、モリブデン、タンタルなどの高融点金属や、ステンレス、ニクロムなどを挙げることができる。また、特に耐食性に優れる窒化アルミニウムをシャワー基板として使用する場合には、熱膨張係数の差が比較的少ないモリブデンやタンタルが好ましい。また、これらは融点が非常に高いため、窒化アルミニウムなどのセラミックスと同時に焼結することができる。これらの材質は、また、メッシュや箔に加工して、成形体の中に埋設した後、焼結することでシャワー基板とすることができる。   The material of the RF electrode is preferably a material whose thermal expansion is close to that of ceramics because it is embedded in a ceramic substrate. For example, refractory metals such as tungsten, molybdenum, and tantalum, stainless steel, nichrome, and the like can be given. Further, when aluminum nitride having excellent corrosion resistance is used as a shower substrate, molybdenum or tantalum having a relatively small difference in thermal expansion coefficient is preferable. Also, since these have a very high melting point, they can be sintered simultaneously with ceramics such as aluminum nitride. These materials can also be processed into meshes or foils, embedded in a molded body, and then sintered to form a shower substrate.

また、セラミックス基板中に形成するRF電極のシート抵抗値としては、50mΩ/□以下が好ましい。これを超えると、近年のウエハの大型化(12インチ化)に伴い、RF電極からシャワー基板の電極部材までの距離が相対的に長くなっているため、シャワー基板の中心部から電極部材までのインピーダンスの絶対値が大きくなってしまう。このためウエハ上に発生するプラズマの強度が弱くなり、所定の膜厚に成膜する時間が長くなって、スループットの低下を引き起こすことがあるため好ましくない。シート抵抗値が10mΩ/□以下であれば、充分に低いインピーダンスとすることが出来るため特に好ましい。   The sheet resistance value of the RF electrode formed in the ceramic substrate is preferably 50 mΩ / □ or less. Beyond this, the distance from the RF electrode to the electrode member of the shower substrate is relatively long with the recent increase in wafer size (12 inches), so the distance from the center of the shower substrate to the electrode member is relatively long. The absolute value of impedance becomes large. For this reason, the intensity of the plasma generated on the wafer is weakened, and it takes a long time to form a film with a predetermined film thickness, which may cause a decrease in throughput. A sheet resistance value of 10 mΩ / □ or less is particularly preferable because a sufficiently low impedance can be obtained.

また、RF電極の膜厚は、3μm以上が好ましい。近年のウエハの大型化に伴い、電極に印加される電力が大きくなり、場合によっては数アンペア(A)を超える電流が電極に流れる。そのため、3μm未満の膜厚では、RF電極自身が発熱してウエハの均熱性を損なうことがあり、最悪の場合はRF回路自体が焼き切れることがある。   The film thickness of the RF electrode is preferably 3 μm or more. With the recent increase in size of wafers, the power applied to the electrodes increases, and in some cases, a current exceeding several amperes (A) flows through the electrodes. For this reason, when the film thickness is less than 3 μm, the RF electrode itself may generate heat and impair the thermal uniformity of the wafer. In the worst case, the RF circuit itself may burn out.

好ましいRF電極の膜厚は5μm以上であり、更には10μm以上である。10μm以上の膜厚であれば、20A程度の電流が流れても、発熱量は比較的小さいため好ましい。しかし、膜厚が100μmを超えると、今度はセラミックスに対する電極の密着性が低下しはじめ、場合によってはセラミックス基板と電極の間に空隙が生じることがあり、所定のインピーダンス値が大きくなってしまうことがある。最も好ましい膜厚としては10〜50μm程度である。   A preferable film thickness of the RF electrode is 5 μm or more, and further 10 μm or more. A film thickness of 10 μm or more is preferable because a calorific value is relatively small even when a current of about 20 A flows. However, when the film thickness exceeds 100 μm, the adhesion of the electrode to the ceramic begins to deteriorate, and in some cases, a gap may be formed between the ceramic substrate and the electrode, resulting in an increase in the predetermined impedance value. There is. The most preferable film thickness is about 10 to 50 μm.

本発明の電極接続構造を有するセラミックス基板は、シャワー基板として好適であるが、当然のことながら、導電体を埋設し且つ腐食性雰囲気にさらされるセラミックス基板、例えばサセプタなど、あらゆる用途のセラミックス基板に対して適用可能である。   The ceramic substrate having the electrode connection structure of the present invention is suitable as a shower substrate, but it is natural that the ceramic substrate is embedded in a conductor and exposed to a corrosive atmosphere, for example, a ceramic substrate for all uses such as a susceptor. It is applicable to.

[実施例1]
厚さ2mm、直径350mmの窒化アルミニウム(AlN)基板1枚と、厚さ6mm、直径350mmのAlN基板1枚を用意した。厚さ6mmのAlN基板にRF電極としてWペーストをスクリーン印刷し、窒素雰囲気中にて1800℃で焼成した。このとき、RF電極は、ガスが通過する貫通穴となる部分を避けて印刷した。尚、RF電極は、基板外周部の6箇所に均等に配置した。
[Example 1]
One aluminum nitride (AlN) substrate having a thickness of 2 mm and a diameter of 350 mm and one AlN substrate having a thickness of 6 mm and a diameter of 350 mm were prepared. A W paste as an RF electrode was screen-printed on an AlN substrate having a thickness of 6 mm and fired at 1800 ° C. in a nitrogen atmosphere. At this time, the RF electrode was printed while avoiding a portion serving as a through hole through which gas passes. The RF electrodes were evenly arranged at six locations on the outer periphery of the substrate.

このWペーストの上に窒化アルミニウムペーストを塗布し、窒素雰囲気中にて1800℃で焼成した。このとき、厚さ6mmのAlN基板には、外部電源に接続する電極形成部に直径3mmの貫通孔を形成し、内部にWペーストを塗布し、RF電極焼成時に同時に焼成した。   An aluminum nitride paste was applied onto the W paste and baked at 1800 ° C. in a nitrogen atmosphere. At this time, a through hole having a diameter of 3 mm was formed in an electrode forming portion connected to an external power source in an AlN substrate having a thickness of 6 mm, a W paste was applied inside, and fired simultaneously with firing of the RF electrode.

その後、他方の厚さ2mmのAlN基板にAlN−Al−Y系ペーストを塗布し、上記厚さ6mmのAlN基板の電極印刷面と接合した。このAlN基板の接合条件は、窒素雰囲気中1800℃にて、20tの荷重をかけてホットプレス接合を行った。また、シャワー基板とするため、機械加工により直径1mmの貫通孔を1000形成した。 Thereafter, an AlN—Al 2 O 3 —Y 2 O 3 paste was applied to the other 2 mm thick AlN substrate, and bonded to the electrode printing surface of the 6 mm thick AlN substrate. The bonding conditions of this AlN substrate were hot press bonding under a nitrogen atmosphere at 1800 ° C. with a load of 20 t. Further, 1000 through-holes having a diameter of 1 mm were formed by machining to form a shower substrate.

得られたシャワー基板となるAlN基板の電極形成部に、深さ5mmの位置までM5の雌ネジ加工を行い、電極部材の挿入部を形成した。そして、コバール、タングステン、モリブデンからなる円柱体の外周面に雄ネジを形成し、その外周面にニッケルメッキを施して電極部材とした。この電極部材を上記電極部材の挿入部に螺合して、AlN基板内のRF電極部と電気的に接続した。   The electrode forming portion of the AlN substrate to be the obtained shower substrate was subjected to M5 female thread processing to a depth of 5 mm to form an insertion portion for the electrode member. And the external thread was formed in the outer peripheral surface of the cylindrical body which consists of Kovar, tungsten, and molybdenum, and nickel plating was given to the outer peripheral surface, and it was set as the electrode member. This electrode member was screwed into the insertion portion of the electrode member and electrically connected to the RF electrode portion in the AlN substrate.

その後、AlN基板表面から突き出た電極部材に、内部に雌ネジを形成したアルミニウム又はニッケルからなるカバー部材を螺合して接続した。その際、カバー部材とシャワー基板の間にO−リングを装着し、カバー部材をAlN基板にネジ止めして密着させることでO−リングを押しつぶし、電極部材をチャンバー内雰囲気から隔絶できるように封止した。また、AlN基板とカバー部材のO−リングとの接触面は、いずれも表面粗さをRa=1.0μmとした。   Thereafter, a cover member made of aluminum or nickel having a female screw formed therein was screwed and connected to the electrode member protruding from the surface of the AlN substrate. At that time, an O-ring is attached between the cover member and the shower substrate, and the cover member is screwed to the AlN substrate and brought into close contact to crush the O-ring so that the electrode member can be isolated from the chamber atmosphere. Stopped. The contact surface between the AlN substrate and the O-ring of the cover member had a surface roughness Ra = 1.0 μm.

このようにして、図1の構造を有するAlN製のシャワー基板を製造した。これらのシャワー基板について、100〜250℃の温度を加え、常温に戻す温度サイクルを10回繰り返した後、その信頼性を確認した。尚、電極部材とカバー部材、電極部材とAlN基板の螺合長さは、いずれも5mmとした。得られた結果を下記表1に示す。   In this manner, an AlN shower substrate having the structure of FIG. 1 was manufactured. About these shower substrates, the temperature of 100-250 degreeC was added, and the temperature cycle which returns to normal temperature was repeated 10 times, Then, the reliability was confirmed. The screwing length between the electrode member and the cover member, and between the electrode member and the AlN substrate was 5 mm. The obtained results are shown in Table 1 below.

Figure 2008294016
Figure 2008294016

上記の結果から、カバー部材の材質と、温度サイクル試験で加える温度によっては、窒化アルミニウム基板のネジ山にクラックが発生することが分る。   From the above results, it can be seen that cracks occur in the thread of the aluminum nitride substrate depending on the material of the cover member and the temperature applied in the temperature cycle test.

[実施例2]
上記実施例1と同様にしてAlN製のシャワー基板を製造したが、カバー部材とAlN基板との間に20μmの空隙を設けた。得られた各シャワー基板について、上記実施例1と同じ条件で実験を行い、その結果を下記表2に示した。
[Example 2]
A shower substrate made of AlN was manufactured in the same manner as in Example 1, but a 20 μm gap was provided between the cover member and the AlN substrate. About each obtained shower board | substrate, it experimented on the same conditions as the said Example 1, The result was shown in following Table 2. FIG.

Figure 2008294016
Figure 2008294016

上記の結果から、AlN基板とカバー部材の間に空隙を設けることによって、温度サイクル試験においてクラックの発生や導通不良は起こらなくなり、上記実施例1のシャワー基板よりも信頼性が向上したことが分る。   From the above results, it can be seen that by providing a gap between the AlN substrate and the cover member, cracking and conduction failure do not occur in the temperature cycle test, and the reliability is improved compared to the shower substrate of Example 1 above. The

[実施例3]
上記実施例1と同様にAlN基板、電極部材、カバー部材を用いたが、AlN基板にはM5ネジが挿入できるようにステンレス製のヘリサートを挿入し、そこに電極部材を捻じ込むことにより、図3の構造を有するAlN製のシャワー基板を製造した。
[Example 3]
The AlN substrate, electrode member, and cover member were used in the same manner as in Example 1 above, but a stainless steel helisert was inserted into the AlN substrate so that an M5 screw could be inserted, and the electrode member was screwed into the figure. A shower substrate made of AlN having the structure 3 was manufactured.

得られた各シャワー基板について、上記実施例1と同じ条件で実験を行ったところ、上記実施例2と同様に全てのサンプルについて良好な結果が得られた。   For each shower substrate obtained, an experiment was performed under the same conditions as in Example 1. As a result, good results were obtained for all the samples as in Example 2.

[実施例4]
上記実施例1と同様にしてAlN製のシャワー基板を製造したが、カバー部材と電極部材の間に、外周に長さ5mm、外径M5の雄ネジ、内周にM2の雌ネジを形成した応力緩和部材を挿入した。応力緩和部材の材質は、アルミニウム、ニッケルの2種類を準備した。
[Example 4]
A shower substrate made of AlN was manufactured in the same manner as in Example 1, but a male screw having a length of 5 mm and an outer diameter of M5 was formed on the outer periphery and a female screw of M2 was formed on the inner periphery between the cover member and the electrode member. A stress relaxation member was inserted. Two types of materials for the stress relaxation member, aluminum and nickel, were prepared.

得られた図2の構造を有する各シャワー基板について、上記実施例1と同じ条件で実験を行ったところ、上記実施例2及び3と同様に全てのサンプルについて良好な結果が得られた。   For each shower substrate having the structure of FIG. 2 obtained, an experiment was conducted under the same conditions as in Example 1. As a result, good results were obtained for all the samples as in Examples 2 and 3.

[実施例5]
上記実施例1と同様にAlN基板、電極部材、カバー部材を用いたが、金属部材として直径10mm、厚さ4mmのタングステン板の中心部にM5のネジ穴を形成し、Niメッキを施したものを準備した。この金属部材をAlN基板内にガラスを用いて接合し、M5のネジ穴に電極部材を捻じ込み、更にカバー部材を電極部材に捻じ込んでO−リングと共に装着した。
[Example 5]
An AlN substrate, an electrode member, and a cover member were used in the same manner as in Example 1 above, but an M5 screw hole was formed in the center of a tungsten plate having a diameter of 10 mm and a thickness of 4 mm as a metal member and Ni plating was applied Prepared. The metal member was bonded to the AlN substrate using glass, the electrode member was screwed into the M5 screw hole, and the cover member was further screwed into the electrode member and mounted together with the O-ring.

得られた図4の構造を有する各シャワー基板について、上記実施例1と同じ条件で実験を行ったところ、上記実施例2及び3と同様に全てのサンプルについて良好な結果が得られた。   For each shower substrate having the structure of FIG. 4 obtained, an experiment was performed under the same conditions as in Example 1. As a result, good results were obtained for all the samples as in Examples 2 and 3.

[実施例6]
上記実施例2と同様にして、カバー部材とAlN基板との間に20μmの空隙を設けたシャワー基板を製造した。その際、カバー部材はアルミニウム、電極部材は比較的腐食されやすいタングステンを使用した。また、セラミックス基板とカバー部材は、O−リングとの接触面の表面粗さRaを変化させた。
[Example 6]
In the same manner as in Example 2, a shower substrate was manufactured in which a gap of 20 μm was provided between the cover member and the AlN substrate. At that time, the cover member was made of aluminum, and the electrode member was made of tungsten which is relatively easily corroded. Moreover, the ceramic substrate and the cover member changed the surface roughness Ra of the contact surface with the O-ring.

得られた各シャワー基板について、加える温度を250℃とした以外は上記実施例1と同じ条件で実験を行い、電極の腐食程度を確認した。得られた結果を下記表3に示した。この結果から、Ra≦2.0μmでは電気抵抗値に変化はなく、更にRa≦1.0μmになると変色も電気抵抗値の変化もなくなり、極めて良好であることが分る。   About each obtained shower board | substrate, experiment was performed on the same conditions as the said Example 1 except the temperature added being 250 degreeC, and the corrosion degree of the electrode was confirmed. The obtained results are shown in Table 3 below. From this result, it can be seen that there is no change in the electric resistance value when Ra ≦ 2.0 μm, and there is no discoloration and no change in the electric resistance value when Ra ≦ 1.0 μm.

Figure 2008294016
Figure 2008294016

[実施例7]
上記実施例1のシャワー基板に対し、AlN基板の電極部材挿入部にステンレス製のヘリサートを挿着し、ニッケルメッキしたモリブデンの電極部材のネジを螺合してRF電極部と接続した。次に、電極部材にアルミニウムのカバー部材を螺合し、カバー部材とシャワー基板の間をO−リングで密着封止して、電極部材をチャンバー内雰囲気から隔絶させた。
[Example 7]
A stainless steel helicate was inserted into the electrode member insertion portion of the AlN substrate with respect to the shower substrate of Example 1 and a screw of a nickel-plated molybdenum electrode member was screwed to connect to the RF electrode portion. Next, an aluminum cover member was screwed into the electrode member, and the cover member and the shower substrate were tightly sealed with an O-ring to isolate the electrode member from the atmosphere in the chamber.

得られたシャワー基板について、カバー部材を高周波電源に接続してプラズマを発生させた。このとき、シャワー基板の外周に均等に配置した電極部材の数、即ちカバー部材の数を1〜10個として、それぞれ発生したプラズマの分布を確認した。   About the obtained shower board | substrate, the cover member was connected to the high frequency power supply, and the plasma was generated. At this time, the number of electrode members arranged uniformly on the outer periphery of the shower substrate, that is, the number of cover members was set to 1 to 10, and the distribution of generated plasma was confirmed.

その結果、電極部材の数が1個では、電極部付近にプラズマが偏り、電極部の反対側との差が大きかった。電極部材の数が2個になると1個の場合よりも緩和されるが、電極間の外周部付近におけるプラズマ密度が低かった。また、電極部材の数が3個では比較的良好であるが、電極間の外周部付近におけるプラズマ密度が若干低かった。これに対して電極部材の数が4〜10個の場合は、均一で良好なプラズマの発生が得られた。   As a result, when the number of electrode members was one, the plasma was biased near the electrode part, and the difference from the opposite side of the electrode part was large. When the number of electrode members is two, the plasma density in the vicinity of the outer peripheral portion between the electrodes is low, although the relaxation is more relaxed than in the case of one. In addition, although the number of electrode members was relatively good with three, the plasma density in the vicinity of the outer peripheral portion between the electrodes was slightly low. In contrast, when the number of electrode members was 4 to 10, uniform and good plasma generation was obtained.

本発明のセラミックス基板における電極接続構造の一具体例を示す概略の断面図である。It is a schematic sectional drawing which shows one specific example of the electrode connection structure in the ceramic substrate of this invention. 本発明のセラミックス基板における電極接続構造の応力緩和材を設けた具体例を示す概略の断面図である。It is a schematic sectional drawing which shows the specific example which provided the stress relaxation material of the electrode connection structure in the ceramic substrate of this invention. 本発明のセラミックス基板における電極接続構造のヘリサートを設けた具体例を示す概略の断面図である。It is a schematic sectional drawing which shows the specific example which provided the helicate of the electrode connection structure in the ceramic substrate of this invention. 本発明のセラミックス基板における電極接続構造の金属部材を接合した具体例を示す概略の断面図である。It is a schematic sectional drawing which shows the specific example which joined the metal member of the electrode connection structure in the ceramic substrate of this invention.

符号の説明Explanation of symbols

1 セラミックス基板
2 導電体
3 電極部材
4 カバー部材
5 O−リング
6 給電部
7 取付ネジ
8 応力緩和部材
9 ヘリサート
10 金属部材
11 接合層
DESCRIPTION OF SYMBOLS 1 Ceramic substrate 2 Electric conductor 3 Electrode member 4 Cover member 5 O-ring 6 Feed part 7 Mounting screw 8 Stress relaxation member 9 Helisert 10 Metal member 11 Joining layer

Claims (17)

半導体製造装置のチャンバー内に設置され、内部に導電体を埋設したセラミックス基板であって、該導電体に接続された外部端子接続用の電極部材と、電極部材に接続され且つ電極部材を被覆する導電性のカバー部材と、カバー部材で被覆されている電極部材をチャンバー内雰囲気から遮断する封止構造とを有することを特徴とするセラミックス基板。   A ceramic substrate which is installed in a chamber of a semiconductor manufacturing apparatus and has a conductor embedded therein, and is connected to the electrode member for connecting an external terminal connected to the conductor, and covers the electrode member A ceramic substrate, comprising: a conductive cover member; and a sealing structure that shields the electrode member covered with the cover member from the atmosphere in the chamber. 前記電極部材と前記セラミックス基板とが機械的に接続されていることを特徴とする、請求項1に記載のセラミックス基板。   2. The ceramic substrate according to claim 1, wherein the electrode member and the ceramic substrate are mechanically connected. 前記電極部材と前記カバー部材とが機械的に接続されていることを特徴とする、請求項1又は2に記載のセラミックス基板。   The ceramic substrate according to claim 1 or 2, wherein the electrode member and the cover member are mechanically connected. 前記電極部材と前記カバー部材の間に応力緩和部材を有することを特徴とする、請求項1〜3のいずれかに記載のセラミックス基板。   The ceramic substrate according to claim 1, further comprising a stress relaxation member between the electrode member and the cover member. 前記電極部材と前記セラミックス基板の間に応力緩和部材を有することを特徴とする、請求項1〜3のいずれかに記載のセラミックス基板。   The ceramic substrate according to claim 1, further comprising a stress relaxation member between the electrode member and the ceramic substrate. 前記カバー部材と前記セラミックス基板の間に空隙を有することを特徴とする、請求項1〜5のいずれかに記載のセラミックス基板。   The ceramic substrate according to claim 1, wherein a gap is provided between the cover member and the ceramic substrate. 前記セラミックス基板が窒化アルミニウムであることを特徴とする、請求項1〜6のいずれかに記載のセラミックス基板。   The ceramic substrate according to claim 1, wherein the ceramic substrate is aluminum nitride. 前記電極部材がタングステン、モリブデン、コバール、ステンレス、ニッケルのいずれかであることを特徴とする、請求項1〜7のいずれかに記載のセラミックス基板。   The ceramic substrate according to claim 1, wherein the electrode member is any one of tungsten, molybdenum, Kovar, stainless steel, and nickel. 前記カバー部材がアルミニウム、ニッケル、ステンレスのいずれかであることを特徴とする、請求項1〜8のいずれかに記載のセラミックス基板。   The ceramic substrate according to claim 1, wherein the cover member is one of aluminum, nickel, and stainless steel. 前記応力緩和部材が、前記電極部材と前記カバー部材又は前記電極部材と前記セラミックス基板に機械的に結合されていることを特徴とする、請求項4又は5に記載のセラミックス基板。   The ceramic substrate according to claim 4 or 5, wherein the stress relaxation member is mechanically coupled to the electrode member and the cover member or the electrode member and the ceramic substrate. 前記応力緩和部材がヘリサートであることを特徴とする、請求項10に記載のセラミックス基板。   The ceramic substrate according to claim 10, wherein the stress relaxation member is a helicate. 前記応力緩和部材が円筒体であって、該円筒体の内周面に前記電極部材と接続するための雌ネジを有し、且つ外周面に前記カバー部材又はセラミックス基板と接続するための雄ネジを有することを特徴とする、請求項10に記載のセラミックス基板。   The stress relaxation member is a cylindrical body, has an internal thread for connecting to the electrode member on the inner peripheral surface of the cylindrical body, and an external thread for connecting to the cover member or the ceramic substrate on the outer peripheral surface The ceramic substrate according to claim 10, comprising: 前記セラミックス基板内に接合された金属部材を備え、該金属部材を貫通して雌ネジが形成され、その雌ネジに前記電極部材に設けた雄ネジが螺合貫通していることを特徴とする、請求項1〜3、6〜9のいずれかに記載のセラミックス基板。   A metal member joined to the ceramic substrate is provided, a female screw is formed through the metal member, and a male screw provided on the electrode member is threaded through the female screw. The ceramic substrate according to any one of claims 1 to 3 and 6 to 9. 前記封止構造が、前記セラミックス基板と前記カバー部材の間に装着したO−リングであることを特徴とする、請求項1〜13のいずれかに記載のセラミックス基板。   The ceramic substrate according to any one of claims 1 to 13, wherein the sealing structure is an O-ring mounted between the ceramic substrate and the cover member. 前記O−リングと接触する前記セラミックス基板及び前記カバー部材の表面粗さがRa≦2.0μmであることを特徴とする、請求項14に記載のセラミックス基板。   15. The ceramic substrate according to claim 14, wherein a surface roughness of the ceramic substrate in contact with the O-ring and the cover member is Ra ≦ 2.0 μm. 前記セラミックス基板が複数の貫通孔を有するシャワー基板であることを特徴とする、請求項1〜15のいずれかに記載のセラミックス基板。   The ceramic substrate according to claim 1, wherein the ceramic substrate is a shower substrate having a plurality of through holes. 前記請求項1〜16のいずれかに記載のセラミックス基板が搭載されていることを特徴とする半導体製造装置。   17. A semiconductor manufacturing apparatus on which the ceramic substrate according to claim 1 is mounted.
JP2007134930A 2007-05-22 2007-05-22 Ceramics substrate and semiconductor manufacturing apparatus provided with the same Pending JP2008294016A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009188396A (en) * 2008-01-09 2009-08-20 Ihi Corp Plasma resistance member and plasma processing apparatus
JP2010182729A (en) * 2009-02-03 2010-08-19 Fuji Electric Holdings Co Ltd Plasma cvd device
WO2018190218A1 (en) * 2017-04-14 2018-10-18 住友電気工業株式会社 Showerhead

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009188396A (en) * 2008-01-09 2009-08-20 Ihi Corp Plasma resistance member and plasma processing apparatus
JP2010182729A (en) * 2009-02-03 2010-08-19 Fuji Electric Holdings Co Ltd Plasma cvd device
WO2018190218A1 (en) * 2017-04-14 2018-10-18 住友電気工業株式会社 Showerhead
JPWO2018190218A1 (en) * 2017-04-14 2020-05-14 住友電気工業株式会社 shower head
JP2020184640A (en) * 2017-04-14 2020-11-12 住友電気工業株式会社 shower head
US11195701B2 (en) 2017-04-14 2021-12-07 Sumitomo Electric Industries, Ltd. Showerhead
JP7099495B2 (en) 2017-04-14 2022-07-12 住友電気工業株式会社 shower head

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