JPH0831517B2 - Electrostatic chuck - Google Patents
Electrostatic chuckInfo
- Publication number
- JPH0831517B2 JPH0831517B2 JP8300091A JP8300091A JPH0831517B2 JP H0831517 B2 JPH0831517 B2 JP H0831517B2 JP 8300091 A JP8300091 A JP 8300091A JP 8300091 A JP8300091 A JP 8300091A JP H0831517 B2 JPH0831517 B2 JP H0831517B2
- Authority
- JP
- Japan
- Prior art keywords
- dielectric
- electrostatic chuck
- temperature
- mol
- pbtio
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 229910021193 La 2 O 3 Inorganic materials 0.000 claims description 12
- 239000000919 ceramic Substances 0.000 claims description 9
- 229910002367 SrTiO Inorganic materials 0.000 claims description 5
- 238000001179 sorption measurement Methods 0.000 description 12
- 238000010586 diagram Methods 0.000 description 6
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 5
- 239000002156 adsorbate Substances 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- 229910010413 TiO 2 Inorganic materials 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 239000004065 semiconductor Substances 0.000 description 3
- 238000002336 sorption--desorption measurement Methods 0.000 description 3
- 235000012431 wafers Nutrition 0.000 description 3
- 239000002131 composite material Substances 0.000 description 2
- 239000003989 dielectric material Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- -1 BaTiO 3 Inorganic materials 0.000 description 1
- 238000003795 desorption Methods 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000000059 patterning Methods 0.000 description 1
- 238000001020 plasma etching Methods 0.000 description 1
- 238000007750 plasma spraying Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
Landscapes
- Jigs For Machine Tools (AREA)
- Container, Conveyance, Adherence, Positioning, Of Wafer (AREA)
- Inorganic Insulating Materials (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は静電チャックに関するも
のである。FIELD OF THE INVENTION The present invention relates to an electrostatic chuck.
【０００２】[0002]
【従来の技術】近年、集積回路等の半導体の製造工程で
パターンニング等の微細加工を施すときに半導体ウエハ
ーを固定する治具に静電チャックが用いられている。図
１に示すように、これ等の静電チャックの基本原理は、
誘電体１を隔てて内部電極２と吸着物３との間に電圧を
印加し、両者の間にクーロン力を発現させることによっ
て吸着物３を吸着するものである。静電チャックの単位
面積あたりの吸着力Ｆは次式で与えられる。 Ｆ＝1/2 ε′ε0 (V/d)2 但し、ε′は誘電体の比誘導率、ε0 は真空の誘電率、
Ｖは電圧、ｄは誘電体層の厚みを示す。従って、比誘電
率ε′が大きい程、誘電体の吸着力は大きい。2. Description of the Related Art In recent years, electrostatic chucks have been used as jigs for fixing semiconductor wafers when performing fine processing such as patterning in the manufacturing process of semiconductors such as integrated circuits. As shown in FIG. 1, the basic principle of these electrostatic chucks is
The adsorbate 3 is adsorbed by applying a voltage between the internal electrode 2 and the adsorbate 3 across the dielectric 1 and expressing a Coulomb force between them. The attraction force F per unit area of the electrostatic chuck is given by the following equation. F = 1/2 ε'ε 0 (V / d) 2 where ε'is the relative dielectric constant of the dielectric, ε 0 is the dielectric constant of the vacuum,
V indicates a voltage, and d indicates the thickness of the dielectric layer. Therefore, the larger the relative permittivity ε ', the greater the attracting force of the dielectric.
【０００３】[0003]
【発明が解決しようとする課題】従来、このような静電
チャックは、誘電体としてAl2O3, CaTiO3, BaTiO3 等の
セラミックスを用いたものが知られている（例えば、特
公昭60-58104号参照）。然し、前述の３つの誘電体セラ
ミックスでAl2O3 は吸着／脱着応答速度が体積抵抗率に
より変化し、かつ体積抵抗率は温度の上昇により減少す
る。CaTiO3は温度上昇による絶縁耐圧の低下が大きい。
BaTiO3は比誘電率ε′の温度依存性が大きい為、200 ℃
程度までしか使用できない欠点があった。Conventionally, such an electrostatic chuck is known to use ceramics such as Al 2 O 3 , CaTiO 3 , and BaTiO 3 as a dielectric (for example, Japanese Patent Publication No. Sho 60). -See No. 58104). However, in the above-mentioned three dielectric ceramics, the adsorption / desorption response speed of Al 2 O 3 changes depending on the volume resistivity, and the volume resistivity decreases as the temperature rises. CaTiO 3 has a large decrease in dielectric strength due to temperature rise.
BaTiO 3 has a large temperature dependence of the relative permittivity ε ′, so 200 ℃
There was a drawback that it could only be used to a certain extent.
【０００４】この欠点を解消する為、誘電体を上下２層
以上から構成し、誘電層間には電極を配置し、使用温度
の上昇に従い電圧を印加する電極を下部に切換えてゆく
ことで、吸着力を発現する誘電層の平均体積抵抗率の温
度変化を抑制する静電チャックが特開平 2-160444 号に
記載されている。各誘電体の体積抵抗率はTiO2の添加量
によって調整されている。この場合、Al2O3, Si3N4, Al
N 又はSiC から成る基材のグリーンシート上に、ペース
ト状にした電極を印刷したグリーンシートを熱圧着して
積層した後、焼成して静電チャックを得ている。グリー
ンシート積層法の他に、印刷法、プラズマ溶射、エッチ
ング又は蒸着法も利用できるとしている。然し、この静
電チャックは構造が複雑である上、電圧を印加する電極
を使用温度により選択する機能が必要であった。In order to solve this drawback, the dielectric is composed of two or more layers above and below, the electrodes are arranged between the dielectric layers, and the electrode to which a voltage is applied is switched to the lower part as the operating temperature rises, thereby adsorbing. Japanese Patent Laid-Open No. 2-160444 discloses an electrostatic chuck that suppresses the temperature change of the average volume resistivity of a dielectric layer that exerts force. The volume resistivity of each dielectric is adjusted by the addition amount of TiO 2 . In this case, Al 2 O 3 ,, Si 3 N 4 ,, Al
An electrostatic chuck is obtained by stacking a green sheet on which a paste-like electrode is printed by thermocompression bonding on a green sheet as a base material made of N 2 or SiC, and then firing it. In addition to the green sheet laminating method, a printing method, plasma spraying, etching or vapor deposition method can be used. However, this electrostatic chuck has a complicated structure and needs a function of selecting an electrode to which a voltage is applied according to a working temperature.
【０００５】Al2O3 −TiO2系誘電体はε′≒10である
が、ジョンソン−ラーベリック効果を利用しているの
で、吸着力は高いが、吸着／脱着応答速度が体積抵抗率
により変化する。すなわち、体積抵抗率が1014Ωcm以上
では電圧の印加からウエハの静電チャックへの吸着まで
の時間が長く実用的ではない。脱着に関しても応答が遅
い。体積抵抗率の減少に伴い、吸着／脱着応答速度は大
きくなるが、吸着物に流れる電流を増加する。吸着物で
ある半導体ウエハの保護を考えると体積抵抗率は1011Ω
cm程度が限度とされている。従って使用範囲は体積抵抗
率が1011〜1014Ωcmの範囲にある温度領域に限定され
る。20℃で1014Ωcmの体積抵抗率を持つAl2O3−TiO2系
誘電体が1011Ωcm以上の体積抵抗率を維持できるのは約
200 ℃以下である。CaTiO3誘電体は温度の上昇に伴い絶
縁耐圧が低下するため、必要な吸着力を出す為の印加電
圧が絶縁耐圧を越えないのは200 ℃以下に限られる。Ba
TiO3誘電体はキューリー温度が約120 ℃で、200 ℃程度
までしか高誘電率を維持できない。The Al 2 O 3 —TiO 2 system dielectric has ε′≈10, but since the Johnson-Laberick effect is used, the adsorption force is high, but the adsorption / desorption response speed changes depending on the volume resistivity. To do. That is, when the volume resistivity is 10 14 Ωcm or more, it takes a long time from application of voltage to adsorption of the wafer to the electrostatic chuck, which is not practical. The response is also slow with regard to desorption. As the volume resistivity decreases, the adsorption / desorption response speed increases, but the current flowing through the adsorbate increases. Considering the protection of semiconductor wafers that are adsorbates, the volume resistivity is 10 11 Ω.
The limit is about cm. Therefore, the usable range is limited to the temperature range in which the volume resistivity is in the range of 10 11 to 10 14 Ωcm. Al 2 O 3 -TiO 2 -based dielectrics that have a volume resistivity of 10 14 Ωcm at 20 ° C can maintain a volume resistivity of 10 11 Ωcm or more.
Below 200 ° C. Since the dielectric strength of CaTiO 3 dielectric decreases as the temperature rises, the applied voltage for producing the required adsorption force does not exceed the dielectric strength only at 200 ℃ or less. Ba
The TiO 3 dielectric has a Curie temperature of about 120 ° C and can maintain a high dielectric constant only up to about 200 ° C.
【０００６】[0006]
【課題を解決するための手段】本発明の目的は、簡単な
構造で200 ℃より高温でも良好な作動特性を有する静電
チャックを提供するにある。SUMMARY OF THE INVENTION It is an object of the present invention to provide an electrostatic chuck having a simple structure and good operating characteristics at temperatures above 200.degree.
【０００７】本発明に係る誘電体セラミックスは、PbTi
O3に対して30 mol％以下0mol％より多いLa2O3 又はLa2O
3 ・2TiO2 を含有することができ、或いは90 mol％以下
0mol％より多いBaTiO3又はSrTiO3を含有することができ
る。The dielectric ceramics according to the present invention is PbTi
30 mol% or less with respect to O 3 and more than 0 mol% La 2 O 3 or La 2 O
Can contain 3・ 2TiO 2 or 90 mol% or less
It may contain more than 0 mol% BaTiO 3 or SrTiO 3 .
【０００８】本発明の静電チャックの使用にあたって
は、通常、吸着力を一定に保つ為、温度に対応して電圧
を変えて運転する。従来、一般的に必要とされる吸着力
は、50〜100 g/cm2 である。本発明では目標とする吸着
力を100 g/cm2 以上とし、主要な使用温度範囲内で十分
高い比誘電率が得られるように、誘電体の組成を前述の
範囲内で調整する。When the electrostatic chuck of the present invention is used, the voltage is usually changed according to the temperature in order to keep the adsorption force constant. Conventionally, the generally required adsorption force is 50 to 100 g / cm 2 . In the present invention, the target adsorption force is 100 g / cm 2 or more, and the composition of the dielectric is adjusted within the above range so that a sufficiently high relative dielectric constant can be obtained within the main operating temperature range.
【０００９】本発明に用いる誘電体PbTiO3−La2O3 、Pb
TiO3−BaTiO3、PbTiO3−La2O3 ・2TiO2 及びPbTiO3−Sr
TiO3の温度と比誘電率との関係を図２〜５に夫々示す。
図２〜５の曲線に付した数字はLa2O3 、BaTiO3、La2O3
・2TiO2 及びSrTiO3のモル％を夫々示す。Dielectrics used in the present invention PbTiO 3 —La 2 O 3 , Pb
TiO 3 -BaTiO 3, PbTiO 3 -La 2 O 3 · 2TiO 2 and PbTiO 3 -Sr
The relationship between the temperature of TiO 3 and the relative dielectric constant is shown in FIGS.
The numbers attached to the curves in FIGS. 2 to 5 are La 2 O 3 , BaTiO 3 , and La 2 O 3
· 2TiO shown respectively mol% of 2 and SrTiO 3.
【００１０】[0010]
【作用】以上に示す通り、極めて特定の組成のセラミッ
クスを使用することにより、キューリー点の高い複合強
誘電体が得られる。複合強誘電体の為、誘電率が高く、
吸着力の大きな静電チャック又は低電圧で作動可能な静
電チャックが得られる。なお、PbTiO3セラミックス単体
では、キューリー温度が非常に高く誘電率を維持できる
温度範囲が狭い為、例えば室温〜600 ℃といった広い温
度範囲では、充分な吸着力を得ることができない。As described above, by using a ceramic having a very specific composition, a composite ferroelectric substance having a high Curie point can be obtained. Since it is a composite ferroelectric, it has a high dielectric constant,
An electrostatic chuck having a large attraction force or an electrostatic chuck that can operate at a low voltage can be obtained. Since PbTiO 3 ceramics alone have a very high Curie temperature and a narrow temperature range in which the dielectric constant can be maintained, a sufficient adsorption force cannot be obtained in a wide temperature range from room temperature to 600 ° C., for example.
【００１１】[0011]
【実施例】以下、本発明を実施例につきさらに詳細に説
明する。The present invention will be described below in more detail with reference to examples.
【００１２】実施例１ 88 mol％ PbTiO3 −12 mol％ La2O3から成る誘電体を作
製し、この誘電体を用いて図１に示す構造の静電チャッ
クを製造した。この誘電体の比誘電率ε′は常温で100
0、厚さｄは300 μm であった。電圧Ｖ＝500 Ｖの条件
ではε0 は8.85×10-12 (F/m) であることから、吸着力
Ｆは略々125 g/cm2 であり、一般的に必要とされる吸着
力の50〜100 g/cm2 に対して十分な吸着力が得られた。
この静電チャックは155 ℃でキューリー点に達し、比誘
電率ε′は5600、厚さｄは300 μm で、電圧Ｖは500 Ｖ
で、吸着力Ｆは702.3 g/cm2 と最大となった。この静電
チャックの吸着力を100 g/cm2 と一定とした場合の印加
電圧−温度特性の関係を図６に示す。なお、上記実施例
は本発明の特定の例及び数値につき説明したが、本発明
の広汎な精神と視野を逸脱することなく種々の変更と修
正が可能なこと勿論である。 Example 1 A dielectric made of 88 mol% PbTiO 3 -12 mol% La 2 O 3 was prepared and an electrostatic chuck having the structure shown in FIG. 1 was manufactured using this dielectric. The relative permittivity ε'of this dielectric is 100 at room temperature.
0 and the thickness d was 300 μm. Under the condition of voltage V = 500 V, ε 0 is 8.85 × 10 −12 (F / m), so the adsorption force F is approximately 125 g / cm 2, which is about the generally required adsorption force. A sufficient adsorption force was obtained for 50 to 100 g / cm 2 .
This electrostatic chuck reaches the Curie point at 155 ° C., the relative permittivity ε ′ is 5600, the thickness d is 300 μm, and the voltage V is 500 V.
The adsorption force F reached the maximum at 702.3 g / cm 2 . FIG. 6 shows the relationship between the applied voltage and the temperature characteristics when the attraction force of this electrostatic chuck was constant at 100 g / cm 2 . Although the above embodiments have been described with reference to specific examples and numerical values of the present invention, it goes without saying that various changes and modifications can be made without departing from the broad spirit and scope of the present invention.
【００１３】[0013]
【発明の効果】以上詳細に説明した通り、本発明の静電
チャックは、簡単な構造で200 ℃より高温でも十分な吸
着力が得られる。また、低電圧でも作動可能である為、
産業上極めて有用である。As described in detail above, the electrostatic chuck of the present invention has a simple structure and can obtain a sufficient adsorption force even at a temperature higher than 200 ° C. Also, because it can operate at low voltage,
It is extremely useful in industry.
【図１】静電チャックの原理を示す説明図である。FIG. 1 is an explanatory diagram showing the principle of an electrostatic chuck.
【図２】本発明に用いる誘電体PbTiO3−La2O3 の温度と
比誘電率との関係を示す特性線図である。FIG. 2 is a characteristic diagram showing a relationship between temperature and relative permittivity of dielectric PbTiO 3 —La 2 O 3 used in the present invention.
【図３】本発明に用いる誘電体PbTiO3−BaTiO3の温度と
比誘電率との関係を示す特性線図である。FIG. 3 is a characteristic diagram showing the relationship between the temperature and the relative dielectric constant of the dielectric PbTiO 3 —BaTiO 3 used in the present invention.
【図４】本発明に用いる誘電体PbTiO3−La2O3 ・2TiO2
の温度と比誘電率との関係を示す特性線図である。FIG. 4 is a dielectric PbTiO 3 −La 2 O 3 · 2TiO 2 used in the present invention.
FIG. 3 is a characteristic diagram showing the relationship between the temperature and the relative dielectric constant.
【図５】本発明に用いる誘電体PbTiO3−SrTiO3の温度と
比誘電率との関係を示す特性線図である。FIG. 5 is a characteristic diagram showing the relationship between temperature and relative permittivity of the dielectric PbTiO 3 —SrTiO 3 used in the present invention.
【図６】静電チャックの印加電圧−温度特性の関係を示
す特性線図である。FIG. 6 is a characteristic diagram showing a relationship between an applied voltage and a temperature characteristic of the electrostatic chuck.
Claims (4)
％より多いLa2O3 を含有するPbTiO3−La2O3 から成るこ
とを特徴とする静電チャック。1. Dielectric ceramics 30 mol% or less 0 mol
% Of La 2 O 3 contained in PbTiO 3 —La 2 O 3 electrostatic chuck.
％より多いBaTiO3を含有するPbTiO3−BaTiO3から成るこ
とを特徴とする静電チャック。2. The dielectric ceramic is 90 mol% or less 0 mol
An electrostatic chuck, characterized in that it consists PbTiO 3 -BaTiO 3 containing more than BaTiO 3%.
％より多いLa2O3 ・2TiO2を含有するPbTiO3−La2O3 ・
2TiO2から成ることを特徴とする静電チャック。3. Dielectric ceramics 30 mol% or less 0 mol
% PbTiO 3 −La 2 O 3 · containing more than 2 % La 2 O 3 · 2TiO 2
An electrostatic chuck comprising 2TiO 2 .
％より多いSrTiO3を含有するPbTiO3−SrTiO3から成るこ
とを特徴とする静電チャック。4. Dielectric ceramics 90 mol% or less 0 mol
An electrostatic chuck, characterized in that it consists PbTiO 3 -SrTiO 3 containing more than SrTiO 3%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8300091A JPH0831517B2 (en) | 1991-03-25 | 1991-03-25 | Electrostatic chuck |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8300091A JPH0831517B2 (en) | 1991-03-25 | 1991-03-25 | Electrostatic chuck |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04296040A JPH04296040A (en) | 1992-10-20 |
| JPH0831517B2 true JPH0831517B2 (en) | 1996-03-27 |
Family
ID=13789967
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8300091A Expired - Lifetime JPH0831517B2 (en) | 1991-03-25 | 1991-03-25 | Electrostatic chuck |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0831517B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2865472B2 (en) * | 1992-02-20 | 1999-03-08 | 信越化学工業株式会社 | Electrostatic chuck |
| US5633073A (en) * | 1995-07-14 | 1997-05-27 | Applied Materials, Inc. | Ceramic susceptor with embedded metal electrode and eutectic connection |
| US5817406A (en) * | 1995-07-14 | 1998-10-06 | Applied Materials, Inc. | Ceramic susceptor with embedded metal electrode and brazing material connection |
| KR20000067819A (en) | 1999-04-13 | 2000-11-25 | 가와다 마사오끼 | Electrically conductive ceramics, a process of producing same, and an electrostatic chuck |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6335449A (en) * | 1986-07-30 | 1988-02-16 | 三菱鉱業セメント株式会社 | Manufacture of ceramic composition |
| JPH0815009B2 (en) * | 1987-03-09 | 1996-02-14 | 株式会社村田製作所 | Dielectric porcelain composition |
| JPH0817054B2 (en) * | 1989-02-23 | 1996-02-21 | 株式会社村田製作所 | Dielectric porcelain composition |
-
1991
- 1991-03-25 JP JP8300091A patent/JPH0831517B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04296040A (en) | 1992-10-20 |
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