JP7202852B2

JP7202852B2 - electrostatic chuck

Info

Publication number: JP7202852B2
Application number: JP2018210192A
Authority: JP
Inventors: 朋来村田; 智雄田中; 修吉本
Original assignee: NGK Spark Plug Co Ltd
Current assignee: Niterra Co Ltd
Priority date: 2018-11-08
Filing date: 2018-11-08
Publication date: 2023-01-12
Anticipated expiration: 2038-11-08
Also published as: JP2020077761A

Description

本明細書に開示される技術は、静電チャックに関する。 The technology disclosed herein relates to electrostatic chucks.

例えば半導体製造装置の真空チャンバー内でウェハを保持する保持装置として、静電チャックが用いられる。静電チャックは、例えばセラミックス製の板状部材と、例えば金属製のベース部材と、板状部材とベース部材とを接合する接合部と、板状部材の内部に設けられたチャック電極とを備えており、チャック電極に電圧が印加されることにより発生する静電引力を利用して、板状部材の表面（吸着面）にウェハを吸着して保持する。また、吸着面に保持されたウェハを温めるために、板状部材に発熱用抵抗体が設けられている。接合部は、シリコーン樹脂を含有する緻密体により形成されている（例えば、特許文献１参照）。 For example, an electrostatic chuck is used as a holding device for holding a wafer within a vacuum chamber of a semiconductor manufacturing apparatus. An electrostatic chuck includes a plate-like member made of, for example, ceramics, a base member made of, for example, metal, a joint for joining the plate-like member and the base member, and a chuck electrode provided inside the plate-like member. The wafer is attracted and held on the surface (attraction surface) of the plate-like member using electrostatic attraction generated by applying a voltage to the chuck electrode. Further, a heating resistor is provided on the plate-like member in order to warm the wafer held on the attraction surface. The joint is formed of a dense body containing silicone resin (see, for example, Patent Document 1).

特開２０１４－２０７３７４号公報JP 2014-207374 A

静電チャックでは、一般に、ベース部材は、板状部材の熱伝導率より高い熱伝導率を有する材料により形成されている。また、従来の静電チャックでは、接合部は、比較的に断熱性が低い緻密体により形成されている。このため、発熱用抵抗体から生じた熱が、接合部を介してベース部材に伝達されやすく、板状部材からベース部材への伝熱（熱引き）に起因して板状部材の温度が低下する。その結果、例えば、吸着面に保持されたウェハを十分に温めることができなかったり、吸着面の温度分布の均一性が低下したりするおそれがある。 In electrostatic chucks, the base member is generally made of a material having a higher thermal conductivity than the plate member. Further, in the conventional electrostatic chuck, the joint portion is formed of a dense body with relatively low heat insulation. Therefore, the heat generated from the heating resistor is easily transmitted to the base member via the joint, and the temperature of the plate-shaped member decreases due to the heat transfer (heat transfer) from the plate-shaped member to the base member. do. As a result, for example, the wafer held by the attraction surface may not be sufficiently warmed, or the uniformity of the temperature distribution on the attraction surface may deteriorate.

本明細書では、上述した課題を解決することが可能な技術を開示する。 This specification discloses a technology capable of solving the above-described problems.

本明細書に開示される技術は、例えば、以下の形態として実現することが可能である。 The technology disclosed in this specification can be implemented, for example, in the following forms.

（１）本明細書に開示される静電チャックは、第１の方向に略垂直な第１の表面と、前記第１の表面とは反対側の第２の表面と、を有し、セラミックスにより形成された第１の部材と、前記第１の部材に設けられたチャック電極と、前記第１の部材に設けられた発熱用抵抗体と、第３の表面を有し、前記第３の表面が前記第１の部材の前記第２の表面側に位置するように配置され、前記第１の部材の熱伝導率より高い熱伝導率を有する第２の部材と、前記第１の部材の前記第２の表面と前記第２の部材の前記第３の表面との間に配置されて前記第１の部材と前記第２の部材とを接合する接合部と、を備え、前記第１の部材の前記第１の表面上に対象物を保持する静電チャックにおいて、前記接合部は、前記第１の部材および前記第２の部材より気孔率が高い多孔質体によって形成されており、前記多孔質体には、前記第１の方向に略平行な少なくとも１つの断面において、略円状の形状を有する複数の円状部分と、前記円状部分より幅が狭く、かつ、互いに隣り合う前記円状部分同士を接続する接続部分と、が存在している。 (1) An electrostatic chuck disclosed in this specification has a first surface substantially perpendicular to a first direction and a second surface opposite to the first surface, and is made of ceramics. a chuck electrode provided on the first member; a heating resistor provided on the first member; and a third surface; a second member having a thermal conductivity higher than that of the first member, the second member having a surface positioned on the second surface side of the first member; a joint portion disposed between the second surface and the third surface of the second member and joining the first member and the second member; In the electrostatic chuck that holds an object on the first surface of a member, the joint portion is formed of a porous body having a higher porosity than the first member and the second member, and The porous body includes a plurality of circular portions having a substantially circular shape in at least one cross section substantially parallel to the first direction, and the circular portions narrower than the circular portions and adjacent to each other. There is a connecting portion that connects the circular portions.

本静電チャックでは、接合部は、第１の部材および第２の部材より気孔率が高い多孔質体によって形成されているため、接合部が緻密体によって形成された構成に比べて、第１の部材から第２の部材への熱引きによる第１の部材の温度低下を抑制することができる。また、接合部は、円状部分と接続部分とから構成される形状であるため、円状部分と接続部分とを含まない形状に対して、接合部内において気体に接触する接触面積が広くなり、第１の部材から第２の部材への熱引きを抑制することができる。すなわち、本静電チャックによれば、第１の部材から第２の部材への熱引きによる第１の部材の温度低下を抑制することができる。 In the present electrostatic chuck, the joint portion is formed of a porous body having a higher porosity than the first member and the second member. It is possible to suppress a decrease in the temperature of the first member due to heat transfer from the first member to the second member. In addition, since the joint portion has a shape composed of a circular portion and a connection portion, the contact area in contact with the gas in the joint portion is larger than that of a shape that does not include the circular portion and the connection portion. Heat transfer from the first member to the second member can be suppressed. That is, according to this electrostatic chuck, it is possible to suppress the temperature drop of the first member due to heat transfer from the first member to the second member.

（２）上記静電チャックにおいて、前記少なくとも１つの断面において、前記円状部分の平均粒径は、１０μｍ以下である構成としてもよい。本静電チャックでは、少なくとも１つの断面において、円状部分の平均粒径は１０μｍ以下である。これにより、本静電チャックによれば、円状部分の平均粒径が１０μｍより大きい構成に比べて、接合部での放熱が抑制されるため、第１の部材から接合部側への熱引きによる第１の部材の温度低下を、より効果的に抑制することができる。 (2) In the above electrostatic chuck, in the at least one cross section, the circular portion may have an average grain size of 10 μm or less. In this electrostatic chuck, the average grain size of the circular portion is 10 μm or less in at least one cross section. As a result, according to the present electrostatic chuck, heat dissipation at the joint portion is suppressed compared to a configuration in which the average grain size of the circular portion is larger than 10 μm, so heat transfer from the first member to the joint portion side is suppressed. It is possible to more effectively suppress the temperature drop of the first member due to

（３）上記静電チャックにおいて、前記少なくとも１つの断面において、前記多孔質体の気孔率は、１０％以上、５０％以下である構成としてもよい。本静電チャックでは、少なくとも１つの断面において、多孔質体の気孔率は、１０％以上、５０％以下である。これにより、本静電チャックによれば、多孔質体の気孔率が１０％未満である構成に比べて、接合部の熱伝導率が低いため、第１の部材から第２の部材への熱引きによる第１の部材の温度低下を、より効果的に抑制することができる。また、本静電チャックによれば、多孔質体の気孔率が５０％より高い構成に比べて、気孔率に起因する第１の部材と第２の部材との接合強度の低下を抑制することができる。 (3) In the above electrostatic chuck, the porous body may have a porosity of 10% or more and 50% or less in the at least one cross section. In this electrostatic chuck, the porosity of the porous body is 10% or more and 50% or less in at least one cross section. As a result, according to the present electrostatic chuck, the thermal conductivity of the joint portion is lower than that of the structure in which the porosity of the porous body is less than 10%. A decrease in temperature of the first member due to pulling can be suppressed more effectively. In addition, according to the present electrostatic chuck, compared to a configuration in which the porosity of the porous body is higher than 50%, the deterioration of the bonding strength between the first member and the second member due to the porosity can be suppressed. can be done.

（４）上記静電チャックにおいて、前記接合部は、第１の接合部と、前記第１の接合部と前記第２の部材との間に配置されている第２の接合部と、を含み、前記静電チャックは、さらに、前記第１の接合部と前記第２の接合部との間に配置され、かつ、前記第１の接合部および前記第２の接合部の熱伝導率より低い熱伝導率を有する金属を主成分とする金属部を備える構成としてもよい。本静電チャックでは、接合部を構成する第１の接合部と第２の接合部との間に、金属部が備えられている。金属部は、第１の接合部および第２の接合部の熱伝導率より低い熱伝導率を有する金属を主成分とする。このため、本静電チャックによれば、第１の接合部と第２の接合部に金属部を備えない構成に比べて、第１の部材から第２の部材への熱引きによる第１の部材の温度低下を、より効果的に抑制することができる。 (4) In the above electrostatic chuck, the joint includes a first joint and a second joint disposed between the first joint and the second member. , the electrostatic chuck is further disposed between the first joint and the second joint and has a thermal conductivity lower than that of the first joint and the second joint A configuration including a metal portion containing a metal having thermal conductivity as a main component may be employed. In this electrostatic chuck, a metal portion is provided between the first joint portion and the second joint portion that constitute the joint portion. The metal part is mainly composed of a metal having thermal conductivity lower than that of the first joint part and the second joint part. For this reason, according to the present electrostatic chuck, compared to a configuration in which the first joint portion and the second joint portion are not provided with metal portions, the first joint portion and the second joint portion are not provided with a metal portion. A decrease in the temperature of the member can be suppressed more effectively.

実施形態における静電チャック１００の外観構成を概略的に示す斜視図である。1 is a perspective view schematically showing an external configuration of an electrostatic chuck 100 according to an embodiment; FIG. 実施形態における静電チャック１００のＸＺ断面構成を概略的に示す説明図である。It is an explanatory view showing roughly the XZ section composition of electrostatic chuck 100 in an embodiment. 静電チャック１００における板状部材１０とベース部材２０との接合部分のＸＺ断面構成を概略的に示す説明図である。3 is an explanatory view schematically showing the XZ cross-sectional configuration of the joint portion between the plate member 10 and the base member 20 in the electrostatic chuck 100; FIG. 図３のＸ１部分における接合部３０のＸＺ断面構成を拡大して示す説明図である。It is explanatory drawing which expands and shows the XZ cross-sectional structure of the junction part 30 in the X1 part of FIG. 図４のＸ２部分における接合部３０のＸＺ断面構成を拡大して示す説明図である。It is explanatory drawing which expands and shows the XZ cross-sectional structure of the junction part 30 in X2 part of FIG. 各サンプルにおける接合部の断熱性と耐熱性とに関する評価結果を示す説明図である。FIG. 5 is an explanatory diagram showing evaluation results regarding heat insulation and heat resistance of joints in each sample.

Ａ．実施形態：
Ａ－１．静電チャック１００の構成：
図１は、本実施形態における静電チャック１００の外観構成を概略的に示す斜視図であり、図２は、本実施形態における静電チャック１００のＸＺ断面構成を概略的に示す説明図である。各図には、方向を特定するための互いに直交するＸＹＺ軸が示されている。本明細書では、便宜的に、Ｚ軸正方向を上方向といい、Ｚ軸負方向を下方向というものとするが、静電チャック１００は実際にはそのような向きとは異なる向きで設置されてもよい。 A. Embodiment:
A-1. Configuration of electrostatic chuck 100:
FIG. 1 is a perspective view schematically showing the external configuration of an electrostatic chuck 100 according to this embodiment, and FIG. 2 is an explanatory view schematically showing the XZ cross-sectional configuration of the electrostatic chuck 100 according to this embodiment. . Each figure shows mutually orthogonal XYZ axes for specifying directions. In this specification, for the sake of convenience, the positive direction of the Z-axis is referred to as the upward direction, and the negative direction of the Z-axis is referred to as the downward direction. may be

静電チャック１００は、対象物（例えば半導体ウェハＷ）を静電引力により吸着して保持する装置であり、例えば半導体製造装置の真空チャンバー内でウェハＷを固定するために使用される。静電チャック１００は、所定の配列方向（本実施形態では上下方向（Ｚ軸方向））に並べて配置された板状部材１０およびベース部材２０を備える。板状部材１０とベース部材２０とは、板状部材１０の下面Ｓ２（正確には、後述するメタライズ層６０の下面Ｓ５図２参照）とベース部材２０の上面Ｓ３とが、後述する接合部３０を挟んで上記配列方向に対向するように配置される。すなわち、ベース部材２０は、ベース部材２０の上面Ｓ３が板状部材１０の下面Ｓ２（メタライズ層６０の下面Ｓ５）側に位置するように配置される。 The electrostatic chuck 100 is a device that attracts and holds an object (for example, a semiconductor wafer W) by electrostatic attraction, and is used, for example, to fix the wafer W in a vacuum chamber of a semiconductor manufacturing apparatus. The electrostatic chuck 100 includes a plate-like member 10 and a base member 20 arranged side by side in a predetermined arrangement direction (vertical direction (Z-axis direction) in this embodiment). The plate-like member 10 and the base member 20 are arranged such that the lower surface S2 of the plate-like member 10 (more precisely, the lower surface S5 of the metallized layer 60 described later, see FIG. 2) and the upper surface S3 of the base member 20 are joined at a joint portion 30 described later. are arranged so as to face each other in the arrangement direction. That is, the base member 20 is arranged such that the upper surface S3 of the base member 20 is located on the lower surface S2 of the plate member 10 (the lower surface S5 of the metallized layer 60).

板状部材１０は、上述した配列方向（Ｚ軸方向）に略直交する略円形平面状の上面（以下、「吸着面」という）Ｓ１を有する部材であり、例えばセラミックス（例えば、アルミナや窒化アルミニウム等）により形成されている。板状部材１０の直径は例えば５０ｍｍ～５００ｍｍ程度（通常は２００ｍｍ～３５０ｍｍ程度）であり、板状部材１０の厚さは例えば１ｍｍ～１０ｍｍ程度である。板状部材１０は、特許請求の範囲における第１の部材に相当し、板状部材１０の吸着面Ｓ１は、特許請求の範囲における第１の表面に相当し、板状部材１０の下面Ｓ２は、特許請求の範囲における第２の表面に相当し、Ｚ軸方向は、特許請求の範囲における第１の方向に相当する。また、本明細書では、Ｚ軸方向に直交する方向を「面方向」という。 The plate-shaped member 10 is a member having a substantially circular planar upper surface (hereinafter referred to as “adsorption surface”) S1 substantially orthogonal to the arrangement direction (Z-axis direction) described above. etc.). The plate member 10 has a diameter of, for example, about 50 mm to 500 mm (usually about 200 mm to 350 mm), and a thickness of, for example, about 1 mm to 10 mm. The plate-like member 10 corresponds to the first member in the claims, the adsorption surface S1 of the plate-like member 10 corresponds to the first surface in the claims, and the lower surface S2 of the plate-like member 10 is , corresponds to the second surface in the claims, and the Z-axis direction corresponds to the first direction in the claims. Also, in this specification, a direction perpendicular to the Z-axis direction is referred to as a "plane direction".

図２に示すように、板状部材１０の内部には、導電性材料（例えば、タングステン、モリブデン、白金等）により形成されたチャック電極４０が配置されている。Ｚ軸方向視でのチャック電極４０の形状は、例えば略円形である。チャック電極４０に電源（図示せず）から電圧が印加されると、静電引力が発生し、この静電引力によってウェハＷが板状部材１０の吸着面Ｓ１に吸着固定される。 As shown in FIG. 2, a chuck electrode 40 made of a conductive material (eg, tungsten, molybdenum, platinum, etc.) is arranged inside the plate member 10 . The shape of the chuck electrode 40 as viewed in the Z-axis direction is, for example, a substantially circular shape. When a voltage is applied to the chuck electrode 40 from a power supply (not shown), electrostatic attraction is generated, and the wafer W is attracted and fixed to the attraction surface S1 of the plate member 10 by this electrostatic attraction.

板状部材１０の内部には、また、導電性材料（例えば、タングステン、モリブデン、白金等）を含む抵抗発熱体により構成されたヒータ電極５０が配置されている。ヒータ電極５０に電源（図示せず）から電圧が印加されると、ヒータ電極５０が発熱することによって板状部材１０が温められ、板状部材１０の吸着面Ｓ１に保持されたウェハＷが温められる。これにより、ウェハＷの温度分布の制御が実現される。ヒータ電極５０は、特許請求の範囲における発熱用抵抗体に相当する。 Inside the plate-like member 10, a heater electrode 50 is arranged which is composed of a resistance heating element containing a conductive material (for example, tungsten, molybdenum, platinum, etc.). When a voltage is applied to the heater electrode 50 from a power supply (not shown), the heater electrode 50 generates heat, thereby warming the plate-like member 10, thereby warming the wafer W held on the suction surface S1 of the plate-like member 10. be done. Thereby, control of the temperature distribution of the wafer W is realized. The heater electrode 50 corresponds to a heating resistor in the claims.

ベース部材２０は、例えば板状部材１０と同径の、または、板状部材１０より径が大きい円形平面の板状部材であり、例えば金属（アルミニウム、アルミニウム合金、チタン合金、鉄や銅等）により形成されている。ベース部材２０の熱膨張係数（熱膨張率）は、板状部材１０の熱膨張係数より大きい。例えば、ベース部材２０は、金属により形成され、板状部材１０は、セラミックスにより形成されている。ベース部材２０の直径は例えば２２０ｍｍ～５５０ｍｍ程度（通常は２２０ｍｍ～３５０ｍｍ）であり、ベース部材２０の厚さは例えば２０ｍｍ～４０ｍｍ程度である。ベース部材２０は、特許請求の範囲における第２の部材に相当し、ベース部材２０の上面Ｓ３は、特許請求の範囲における第３の表面に相当する。 The base member 20 is, for example, a circular planar plate-like member having the same diameter as the plate-like member 10 or having a larger diameter than the plate-like member 10, and is made of metal (aluminum, aluminum alloy, titanium alloy, iron, copper, etc.). formed by The coefficient of thermal expansion (coefficient of thermal expansion) of the base member 20 is larger than the coefficient of thermal expansion of the plate member 10 . For example, the base member 20 is made of metal, and the plate member 10 is made of ceramics. The diameter of the base member 20 is, for example, approximately 220 mm to 550 mm (usually 220 mm to 350 mm), and the thickness of the base member 20 is, for example, approximately 20 mm to 40 mm. The base member 20 corresponds to the second member in the claims, and the top surface S3 of the base member 20 corresponds to the third surface in the claims.

ベース部材２０は、板状部材１０の下面Ｓ２とベース部材２０の上面Ｓ３との間に配置された接合部３０によって、板状部材１０に接合されている。接合部３０の厚さは、例えば１０μｍ以上、７０μｍ以下、より好ましくは、８μｍ以上、３０μｍ以下である。また、接合部３０の厚さのばらつきは、該接合部３０の平均厚さに対して±３μｍ以下であることが好ましい。板状部材１０とベース部材２０とを接合するための構成については、後に詳述する。 The base member 20 is joined to the plate member 10 by a joining portion 30 arranged between the lower surface S2 of the plate member 10 and the upper surface S3 of the base member 20. As shown in FIG. The thickness of the joint portion 30 is, for example, 10 μm or more and 70 μm or less, more preferably 8 μm or more and 30 μm or less. Moreover, it is preferable that the variation in the thickness of the joint portion 30 is ±3 μm or less with respect to the average thickness of the joint portion 30 . A configuration for joining the plate member 10 and the base member 20 will be described in detail later.

ベース部材２０の内部には冷媒流路２１が形成されている。冷媒流路２１に冷媒（例えば、フッ素系不活性液体や水等）が流されると、ベース部材２０が冷却され、接合部３０を介したベース部材２０と板状部材１０との間の伝熱（熱引き）により板状部材１０が冷却され、板状部材１０の吸着面Ｓ１に保持されたウェハＷが冷却される。これにより、ウェハＷの温度分布の制御が実現される。 A coolant channel 21 is formed inside the base member 20 . When a coolant (for example, a fluorine-based inert liquid, water, or the like) is caused to flow through the coolant channel 21 , the base member 20 is cooled, and heat is transferred between the base member 20 and the plate-like member 10 via the joint portion 30 . The plate-like member 10 is cooled by (thermal drawing), and the wafer W held on the adsorption surface S1 of the plate-like member 10 is cooled. Thereby, control of the temperature distribution of the wafer W is realized.

また、図２に示すように、静電チャック１００には、ベース部材２０の下面Ｓ４から板状部材１０の吸着面Ｓ１にわたって上下方向に延びるピン挿通孔１４０が形成されている。すなわち、ピン挿通孔１４０は、ベース部材２０をＺ軸方向に貫通する孔２６と、接合部３０をＺ軸方向に貫通する孔３６と、板状部材１０と後述するメタライズ層６０とをＺ軸方向に貫通する孔１６とが互いに連通した一体の孔である。ピン挿通孔１４０は、板状部材１０の吸着面Ｓ１上に保持されたウェハＷを押し上げて吸着面Ｓ１から離間させるためのリフトピン（図示せず）を挿通するための孔である。 Further, as shown in FIG. 2 , the electrostatic chuck 100 is formed with pin insertion holes 140 extending vertically from the lower surface S4 of the base member 20 to the attraction surface S1 of the plate member 10 . That is, the pin insertion hole 140 includes a hole 26 penetrating the base member 20 in the Z-axis direction, a hole 36 penetrating the joint portion 30 in the Z-axis direction, and a plate member 10 and a metallized layer 60 to be described later. The hole 16 passing through in the direction is an integral hole communicating with each other. The pin insertion hole 140 is a hole for inserting a lift pin (not shown) for pushing up the wafer W held on the attraction surface S1 of the plate member 10 to separate it from the attraction surface S1.

また、図２に示すように、静電チャック１００は、板状部材１０とウェハＷとの間の伝熱性を高めてウェハＷの温度分布の制御性をさらに高めるため、板状部材１０の吸着面Ｓ１とウェハＷの表面との間に存在する空間に不活性ガス（例えば、ヘリウムガス）を供給する構成を備えている。すなわち、静電チャック１００には、ベース部材２０の下面Ｓ４から接合部３０の上面にわたって上下方向に延びる第１のガス流路孔１３１と、第１のガス流路孔１３１に連通すると共に板状部材１０の吸着面Ｓ１に開口する第２のガス流路孔１３２とが形成されている。第１のガス流路孔１３１は、ベース部材２０をＺ軸方向に貫通する孔２５と、接合部３０をＺ軸方向に貫通する孔３５とが互いに連通した一体の孔である。また、第２のガス流路孔１３２の下端部は、径が拡大された拡径部１３４となっており、拡径部１３４内には、通気性を有する充填部材（通気性プラグ）１６０が充填されている。また、板状部材１０の内部には、第２のガス流路孔１３２と連通すると共に面方向に環状に延びる横流路１３３が形成されている。ヘリウムガス源（図示しない）から供給されたヘリウムガスが、第１のガス流路孔１３１内に流入すると、流入したヘリウムガスは、第１のガス流路孔１３１から拡径部１３４内に充填された通気性を有する充填部材１６０の内部を通過して板状部材１０の内部の第２のガス流路孔１３２内に流入し、横流路１３３を介して面方向に流れつつ、吸着面Ｓ１に形成されたガス噴出孔から噴出する。このようにして、吸着面Ｓ１とウェハＷの表面との間に存在する空間に、ヘリウムガスが供給される。 Further, as shown in FIG. 2, the electrostatic chuck 100 enhances the heat transfer between the plate-like member 10 and the wafer W to further enhance the controllability of the temperature distribution of the wafer W. A configuration is provided to supply an inert gas (for example, helium gas) to the space existing between the surface S1 and the surface of the wafer W. FIG. That is, the electrostatic chuck 100 has a first gas channel hole 131 extending vertically from the lower surface S4 of the base member 20 to the upper surface of the joint portion 30, and a plate-shaped gas channel hole 131 communicating with the first gas channel hole 131. A second gas flow path hole 132 that opens to the adsorption surface S1 of the member 10 is formed. The first gas passage hole 131 is an integral hole in which the hole 25 passing through the base member 20 in the Z-axis direction and the hole 35 passing through the joint portion 30 in the Z-axis direction communicate with each other. The lower end portion of the second gas passage hole 132 is an enlarged diameter portion 134 having an enlarged diameter, and a filling member (breathable plug) 160 having air permeability is provided in the enlarged diameter portion 134 . filled. Further, inside the plate-like member 10, a lateral channel 133 is formed that communicates with the second gas channel hole 132 and extends annularly in the plane direction. When helium gas supplied from a helium gas source (not shown) flows into the first gas passage hole 131 , the helium gas that has flowed in fills the enlarged diameter portion 134 through the first gas passage hole 131 . It flows through the inside of the filling member 160 having gas permeability, flows into the second gas channel hole 132 inside the plate-like member 10, flows in the planar direction through the horizontal channel 133, and flows on the adsorption surface S1. is ejected from the gas ejection holes formed in the . In this manner, the helium gas is supplied to the space existing between the attraction surface S1 and the surface of the wafer W. As shown in FIG.

Ａ－２．板状部材１０とベース部材２０とを接合するための詳細構成：
次に、板状部材１０とベース部材２０とを接合するための詳細構成について説明する。図３は、静電チャック１００における板状部材１０とベース部材２０との接合部分のＸＺ断面構成を概略的に示す説明図であり、図３には、板状部材１０とメタライズ層６０と接合部３０とベース部材２０とが示されている。図４は、図３のＸ１部分における接合部３０のＸＺ断面構成を拡大して示す説明図であり、図５は、図４のＸ２部分における接合部３０のＸＺ断面構成を拡大して示す説明図である。なお、図３から図５において、接合部３０のうち、斑点ハッチング部分は接合部３０の形成材料であり、黒色部分は気孔Ｐである。 A-2. Detailed configuration for joining plate member 10 and base member 20:
Next, a detailed configuration for joining the plate member 10 and the base member 20 will be described. FIG. 3 is an explanatory view schematically showing the XZ cross-sectional configuration of the joint portion between the plate member 10 and the base member 20 in the electrostatic chuck 100. FIG. Part 30 and base member 20 are shown. 4 is an explanatory view showing an enlarged XZ cross-sectional configuration of the joint 30 at the X1 portion of FIG. 3, and FIG. 5 is an enlarged explanation showing the XZ cross-sectional configuration of the joint 30 at the X2 portion of FIG. It is a diagram. 3 to 5, of the joint 30, the dotted hatched portion is the forming material of the joint 30, and the black portion is the pore P. As shown in FIG.

図２および図３に示すように、本実施形態の静電チャック１００では、板状部材１０の下面Ｓ２には、メタライズ層６０が形成されている。メタライズ層６０は、板状部材１０の下面Ｓ２のうち、孔１６や拡径部１３４の形成部分を除く、表面部分全体を覆っている。メタライズ層６０は、主成分として、導電性材料（例えば、Ａｇ、Ｃｕ、Ａｕ、Ｐｔ、Ｐｂ、Ｎｉ－Ａｕフラッシュなど）を含む材料により形成された金属膜である。メタライズ層６０のＺ軸方向の厚さは、板状部材１０のＺ軸方向の厚さより薄く、例えば０．１μｍ程度である。 As shown in FIGS. 2 and 3, in the electrostatic chuck 100 of the present embodiment, a metallized layer 60 is formed on the lower surface S2 of the plate member 10. As shown in FIG. The metallized layer 60 covers the entire surface portion of the lower surface S2 of the plate member 10, excluding the portions where the holes 16 and the enlarged diameter portion 134 are formed. The metallized layer 60 is a metal film made of a material containing a conductive material (eg, Ag, Cu, Au, Pt, Pb, Ni—Au flash, etc.) as a main component. The thickness of the metallized layer 60 in the Z-axis direction is thinner than the thickness of the plate member 10 in the Z-axis direction, and is, for example, about 0.1 μm.

接合部３０は、多孔質体により形成されている。接合部３０を形成する多孔質体の気孔率は、板状部材１０の気孔率より高く、かつ、ベース部材２０の気孔率より高い。接合部３０を形成する多孔質体の気孔率は、例えば、２０％以上、７０％以下である。また、接合部３０は、主成分として、粒径が１００ｎｍ以下の金属超微粒子を含んでいる。具体的には、接合部３０は、金属ナノ粒子（例えばＡｇナノ粒子やＣｕナノ粒子）の焼結体である。ここでいう主成分とは、含有割合（重量割合）の最も多い成分を意味する。図３および図４に示すように、接合部３０は、複数の金属ナノ粒子が焼結して互いに接合したナノ金属粒子接合体である。このナノ金属粒子接合は、金属ナノ粒子同士の固相拡散接合（固相焼結）である。このため、接合部３０では、金属ナノ粒子同士が固相（粒状）のまま接合することによって固相間に気孔Ｐが形成されており、その結果、接合部３０は多孔質体になっている。なお、金属超微粒子を構成する元素としては、室温における熱伝導率が２５０ｗ／ｍ・Ｋ以上であり、かつ、非磁性である元素であることが好ましい。 The joint portion 30 is made of a porous material. The porosity of the porous body forming the joint portion 30 is higher than the porosity of the plate member 10 and higher than the porosity of the base member 20 . The porosity of the porous body forming the joint portion 30 is, for example, 20% or more and 70% or less. In addition, the joint portion 30 contains, as a main component, metal ultrafine particles having a particle size of 100 nm or less. Specifically, the joint 30 is a sintered body of metal nanoparticles (for example, Ag nanoparticles or Cu nanoparticles). The term "main component" as used herein means the component with the highest content ratio (weight ratio). As shown in FIGS. 3 and 4, the joint 30 is a metal nanoparticle joined body in which a plurality of metal nanoparticles are sintered and joined together. This metal nanoparticle bonding is solid phase diffusion bonding (solid phase sintering) between metal nanoparticles. Therefore, in the joint portion 30, the metal nanoparticles are joined to each other in a solid phase (granular form) to form pores P between the solid phases, and as a result, the joint portion 30 is a porous body. . It should be noted that the element constituting the ultrafine metal particles preferably has a thermal conductivity of 250 w/m·K or more at room temperature and is non-magnetic.

本実施形態の静電チャック１００は、接合部３０を形成する多孔質体に関する第１の条件を満たす。
＜第１の条件＞
接合部３０を形成する多孔質体を含むＺ軸方向に略平行な少なくとも１つの断面において、略円状（丸状、顆粒状）の形状を有する複数の円状部分３２と、円状部分３２より幅が狭く、かつ、互いに隣り合う円状部分３２同士を接続する接続部分３４と、が存在している（図３から図５参照）。接続部分３４には、Ｚ軸方向において互いに異なる位置に配置された複数の円状部分３２同士を接続するものと、面方向において互いに異なる位置に配置された複数の円状部分３２同士を接続するものとが含まれる。なお、接合部３０の断面について、電子顕微鏡により例えば２，０００倍～２０，０００倍の倍率で断面観察することにより、接合部３０における円状部分３２および接続部分３４の有無を確認することができる。 The electrostatic chuck 100 of this embodiment satisfies the first condition regarding the porous body that forms the joint portion 30 .
<First condition>
A plurality of circular portions 32 having a substantially circular (round, granular) shape in at least one cross section substantially parallel to the Z-axis direction including the porous body forming the joint portion 30, and the circular portions 32 There is a connecting portion 34 which is narrower and connects adjacent circular portions 32 (see FIGS. 3 to 5). The connecting portion 34 connects a plurality of circular portions 32 arranged at mutually different positions in the Z-axis direction, and connects a plurality of circular portions 32 arranged at mutually different positions in the planar direction. Things are included. Note that the presence or absence of the circular portion 32 and the connecting portion 34 in the joint portion 30 can be confirmed by observing the cross section of the joint portion 30 with an electron microscope at a magnification of, for example, 2,000 times to 20,000 times. can.

なお、図３に示すように、接合部３０（多孔質体）は、複数の円状部分３２と複数の接続部分３４とが連続的につながっている経路に沿って、円状部分３２と接続部分３４とが交互に配置されている交互配列部分を有する。さらに、接合部３０は、接合部３０のＺ軸方向の一端から他端まで、円状部分３２と接続部分３４とが連続的につながっている連続部分３３を有する。 In addition, as shown in FIG. 3 , the joint portion 30 (porous body) is connected to the circular portions 32 along a path in which the plurality of circular portions 32 and the plurality of connecting portions 34 are continuously connected. It has alternating portions in which the portions 34 are alternately arranged. Furthermore, the joint portion 30 has a continuous portion 33 in which the circular portion 32 and the connecting portion 34 are continuously connected from one end to the other end in the Z-axis direction of the joint portion 30 .

本実施形態の静電チャック１００は、さらに、接合部３０を形成する多孔質体に関する第２の条件を満たすことが好ましい。
＜第２の条件＞
接合部３０を形成する多孔質体を含むＺ軸方向に略平行な少なくとも１つの断面において、円状部分３２の平均粒径は、１０μｍ以下である。なお、円状部分３２の平均粒径は、０．０１μｍ以上であることが好ましい。 It is preferable that the electrostatic chuck 100 of the present embodiment further satisfies the second condition regarding the porous body that forms the joint portion 30 .
<Second condition>
In at least one section substantially parallel to the Z-axis direction including the porous body forming the joint portion 30, the average grain size of the circular portion 32 is 10 μm or less. The average particle diameter of the circular portion 32 is preferably 0.01 μm or more.

なお、円状部分３２の平均粒径は、次のようにして特定するものとする。まず、静電チャック１００における接合部３０を切り出して、接合部３０のＺ軸方向に略平行な断面を作製し、その接合部３０の断面を鏡面研磨した後に、イオンミリング法によるＣＰ（クロスセクションポリッシャ）加工を施す。次に、ＥＰＭＡ（電子線マイクロアナライザ）を用いて、そのＣＰ加工後の接合部３０の断面画像（２，０００～２０，０００倍）を得る。次に、接合部３０の断面画像において、面方向に平行な複数（例えば３本）の直線線分Ｌ（図４参照）を、Ｚ軸方向に所定の間隔（例えば１から５μｍ間隔）で引く。各直線線分Ｌは、所定数（例えば２０個）以上の円状部分３２と交差する直線である。各直線線分Ｌについて、該直線線分Ｌと交差する測定対象の複数の円状部分３２の粒径を測定する。ここでいう円状部分３２の粒径は、各円状部分３２に内接する内接円の直径である。そして、複数の直線線分Ｌについて、測定対象の全ての円状部分３２の粒径の平均値を、接合部３０における円状部分３２の平均粒径とする。 In addition, the average particle size of the circular portion 32 shall be specified as follows. First, the joint portion 30 in the electrostatic chuck 100 is cut out to prepare a cross section of the joint portion 30 substantially parallel to the Z-axis direction. polisher) processing. Next, an EPMA (electron probe microanalyzer) is used to obtain a cross-sectional image (2,000 to 20,000 times) of the joint 30 after the CP processing. Next, in the cross-sectional image of the joint 30, a plurality of (eg, three) straight line segments L (see FIG. 4) parallel to the surface direction are drawn at predetermined intervals (eg, intervals of 1 to 5 μm) in the Z-axis direction. . Each straight line segment L is a straight line that intersects a predetermined number (for example, 20) or more circular portions 32 . For each straight line segment L, the grain size of a plurality of circular portions 32 to be measured that intersect the straight line segment L is measured. The particle size of the circular portion 32 referred to here is the diameter of the inscribed circle that inscribes each circular portion 32 . Then, regarding the plurality of straight line segments L, the average value of the grain sizes of all the circular portions 32 to be measured is taken as the average grain size of the circular portions 32 in the joint portion 30 .

本実施形態の静電チャック１００は、さらに、接合部３０を形成する多孔質体に関する第３の条件を満たすことが好ましい。
＜第３の条件＞
接合部３０を形成する多孔質体を含むＺ軸方向に略平行な少なくとも１つの断面において、多孔質体の気孔率は、１０％以上、５０％以下である。 It is preferable that the electrostatic chuck 100 of the present embodiment further satisfies a third condition regarding the porous body that forms the joint portion 30 .
<Third condition>
The porosity of the porous body is 10% or more and 50% or less in at least one cross section substantially parallel to the Z-axis direction including the porous body forming the joint portion 30 .

なお、多孔質体の気孔率は、次のようにして特定するものとする。上述した円状部分３２の平均粒径の特定方法と同様に、接合部３０の断面画像（２，０００～２０，０００倍）を得る。次に、接合部３０の断面画像において、上述した円状部分３２の平均粒径の特定方法と同様に、複数（例えば３本）の直線線分（図示しない。上記直線線分Ｌと同じでもよい）を、Ｚ軸方向に所定の間隔（例えば１から５μｍ間隔）で引く。各直線線分上の気孔Ｐにあたる部分の長さを測定し、直線の全長に対する気孔Ｐにあたる部分の長さの合計の比を、当該直線線分上における気孔率とする。そして、複数の直線線分について求められた気孔率の平均値を、多孔質体の気孔率とする。 In addition, the porosity of the porous body shall be specified as follows. A cross-sectional image (magnification of 2,000 to 20,000) of the joint 30 is obtained in the same manner as in the method for specifying the average grain size of the circular portion 32 described above. Next, in the cross-sectional image of the joint 30, a plurality of (for example, three) straight line segments (not shown. good) are drawn at predetermined intervals (for example, intervals of 1 to 5 μm) in the Z-axis direction. The length of the portion corresponding to the pore P on each straight line segment is measured, and the ratio of the total length of the portion corresponding to the pore P to the total length of the straight line is taken as the porosity on the straight line segment. Then, the average value of the porosities obtained for the plurality of straight line segments is taken as the porosity of the porous body.

Ａ－３．静電チャック１００の製造方法：
本実施形態の静電チャック１００の製造方法は、例えば以下の通りである。まず、公知の方法により、板状部材１０を作製する。例えば、セラミックスグリーンシートを複数枚作製し、所定のセラミックスグリーンシートに所定の加工を行う。所定の加工としては、例えば、チャック電極４０やヒータ電極５０等の形成のためのメタライズペーストの印刷、各種ビアの形成のための孔空けおよびメタライズペーストの充填等が挙げられる。これらのセラミックスグリーンシートを積層して熱圧着し、切断等の加工を行うことにより、セラミックスグリーンシートの積層体を作製する。作製されたセラミックスグリーンシートの積層体を焼成することにより、セラミックス焼成体である板状部材１０を作製する。また、公知の方法により、ベース部材２０を作製する。 A-3. Manufacturing method of electrostatic chuck 100:
A method for manufacturing the electrostatic chuck 100 of the present embodiment is, for example, as follows. First, the plate member 10 is produced by a known method. For example, a plurality of ceramic green sheets are produced, and predetermined processing is performed on predetermined ceramic green sheets. The predetermined processing includes, for example, printing of metallizing paste for forming the chuck electrode 40 and the heater electrode 50, drilling holes for forming various vias, and filling with metallizing paste. These ceramic green sheets are laminated, thermocompressed, and processed such as cutting to produce a ceramic green sheet laminate. By sintering the produced laminate of ceramic green sheets, the plate member 10, which is a ceramic sintered body, is produced. Also, the base member 20 is produced by a known method.

次に、板状部材１０の下面Ｓ２にメタライズ層６０を形成する。例えば、板状部材１０がアルミナにより形成されている場合、板状部材１０の下面Ｓ２に、モリブデンマンガン法やコファイア法により金属膜（例えばＮｉ等のストライクメッキ）を形成した後にＡｇ、Ｃｕ、Ａｕ等のめっきを施す。これにより、ベース部材２０の上面Ｓ３側に配置される最外層がＡｇ、Ｃｕ、Ａｕ等により形成されたメタライズ層６０を形成することができる。なお、メタライズ層６０を形成する他の方法としては、金属蒸着、スパッタ、物理蒸着（ＰＶＤ）が挙げられる。なお、板状部材１０とメタライズ層６０との密着性向上のため、例えば、板状部材１０の下面Ｓ２側から、Ｔｉ、Ｍｏ、最外層（約０．１μｍ）の順に成膜してもよい。 Next, a metallized layer 60 is formed on the lower surface S2 of the plate member 10. As shown in FIG. For example, when the plate-like member 10 is made of alumina, a metal film (for example, strike plating of Ni or the like) is formed on the lower surface S2 of the plate-like member 10 by a molybdenum manganese method or a cofire method, and then Ag, Cu, Au is formed. etc. are plated. As a result, the metallized layer 60, which is arranged on the upper surface S3 side of the base member 20 and whose outermost layer is made of Ag, Cu, Au, or the like, can be formed. Other methods of forming the metallization layer 60 include metal vapor deposition, sputtering, and physical vapor deposition (PVD). In order to improve the adhesion between the plate-like member 10 and the metallized layer 60, for example, Ti, Mo, and the outermost layer (about 0.1 μm) may be deposited in this order from the lower surface S2 side of the plate-like member 10. .

次に、金属ナノ粒子を主成分とするペーストを、ベース部材２０の上面Ｓ３上に膜状に塗布した後、その塗布されたペーストの上に板状部材１０をマウントすることにより、板状部材１０に形成されたメタライズ層６０の下面Ｓ５とベース部材２０の上面Ｓ３との間にペーストを挟み込ませる。そして、板状部材１０に対して、ベース部材２０側に向かう方向に、例えば、約０．１Ｎ／ｍｍ^２～１．０Ｎ／ｍｍ^２程度の圧力を加え、窒素雰囲気で２７０℃の熱処理を１時間施すことにより、板状部材１０に形成されたメタライズ層６０とベース部材２０とを接合する接合部３０を形成する。以上の工程により、本実施形態の静電チャック１００が製造される。 Next, a paste containing metal nanoparticles as a main component is applied in the form of a film on the upper surface S3 of the base member 20, and then the plate-like member 10 is mounted on the applied paste to obtain a plate-like member. The paste is sandwiched between the lower surface S5 of the metallized layer 60 formed in 10 and the upper surface S3 of the base member 20. As shown in FIG. Then, a pressure of, for example, about 0.1 N/mm ² to 1.0 N/mm ² is applied to the plate member 10 in the direction toward the base member 20 side, and heat treatment is performed at 270° C. in a nitrogen atmosphere for 1 time. By applying for a period of time, the joint portion 30 that joins the metallized layer 60 formed on the plate member 10 and the base member 20 is formed. The electrostatic chuck 100 of the present embodiment is manufactured through the above steps.

Ａ－４．本実施形態の効果：
以上説明したように、本実施形態の静電チャック１００は、板状部材１０と、ベース部材２０と、接合部３０とを備える。接合部３０は、板状部材１０およびベース部材２０より気孔率が高い多孔質体によって形成されている。このため、本実施形態によれば、接合部が緻密体によって形成された構成に比べて、板状部材１０からベース部材２０への熱引きによる板状部材１０の温度低下を抑制することができる。さらに、接合部３０は、円状部分３２と接続部分３４とから構成される形状である（上記第１の条件）。このため、円状部分３２と接続部分３４とを含まない形状に対して、接合部３０内において、接合部３０より熱伝導率が低い気体に接触する接触面積が広くなり、板状部材１０からベース部材２０への熱引きを抑制することができる。すなわち、本実施形態によれば、板状部材１０からベース部材２０への熱引きによる板状部材１０の温度低下を抑制することができる。その結果、例えば、板状部材１０の吸着面Ｓ１に保持されたウェハＷをヒータ電極５０によって効率良く温めることができ、また、吸着面Ｓ１の温度分布の均一性が低下することを抑制することができる。 A-4. Effect of this embodiment:
As described above, the electrostatic chuck 100 of this embodiment includes the plate member 10, the base member 20, and the joint portion 30. As shown in FIG. The joint portion 30 is made of a porous material having a higher porosity than the plate member 10 and the base member 20 . Therefore, according to the present embodiment, it is possible to suppress a decrease in the temperature of the plate-like member 10 due to heat transfer from the plate-like member 10 to the base member 20, compared to a structure in which the joint portion is formed of a dense body. . Furthermore, the joint portion 30 has a shape composed of a circular portion 32 and a connecting portion 34 (the above first condition). For this reason, compared to a shape that does not include the circular portion 32 and the connection portion 34 , the contact area in the joint portion 30 that contacts the gas having a lower thermal conductivity than that of the joint portion 30 is widened, and the plate-like member 10 Heat transfer to the base member 20 can be suppressed. That is, according to the present embodiment, it is possible to suppress the temperature drop of the plate-like member 10 due to heat transfer from the plate-like member 10 to the base member 20 . As a result, for example, the wafer W held on the attraction surface S1 of the plate-like member 10 can be efficiently heated by the heater electrode 50, and deterioration of the uniformity of the temperature distribution of the attraction surface S1 can be suppressed. can be done.

なお、本実施形態では、上述したように、接合部３０（多孔質体）は、接合部３０のＺ軸方向の一端から他端まで、円状部分３２と接続部分３４とが連続的につながっている連続部分３３を有する。これにより、接合部３０に連続部分３３が存在しない構成に比べて、板状部材１０とベース部材２０との接合強度を向上させることができる。また、本実施形態によれば、接合部３０が緻密体によって形成された構成に比べて、板状部材１０とベース部材２０との熱膨張差による応力を緩和する応力緩和性を向上させることができる。また、本実施形態では、セラミックスにより形成された板状部材１０の下面Ｓ２にメタライズ層６０が形成され、このメタライズ層６０とベース部材２０とが、接合部３０を形成する多孔質体によって接合されている。このため、板状部材１０と多孔質体とが、メタライズ層６０を介さずに直接接触する構成に比べて、板状部材１０と多孔質体との接合強度が向上する。 In the present embodiment, as described above, in the joint portion 30 (porous body), the circular portion 32 and the connection portion 34 are continuously connected from one end to the other end of the joint portion 30 in the Z-axis direction. It has a continuous portion 33 that As a result, the bonding strength between the plate member 10 and the base member 20 can be improved compared to a configuration in which the connecting portion 30 does not have the continuous portion 33 . In addition, according to the present embodiment, compared to the structure in which the joint portion 30 is formed of a dense body, it is possible to improve the stress relaxation property of relieving the stress due to the difference in thermal expansion between the plate member 10 and the base member 20. can. Further, in this embodiment, the metallized layer 60 is formed on the lower surface S2 of the plate-like member 10 made of ceramics, and the metallized layer 60 and the base member 20 are joined by the porous body that forms the joining portion 30. ing. Therefore, the bonding strength between the plate-like member 10 and the porous body is improved as compared with the structure in which the plate-like member 10 and the porous body are in direct contact with each other without the metallized layer 60 interposed therebetween.

また、本実施形態では、接合部３０の少なくとも１つの断面において、円状部分３２の平均粒径は１０μｍ以下である（上記第２の条件）。これにより、本実施形態によれば、円状部分３２の平均粒径が１０μｍより大きい構成に比べて、接合部３０での放熱が抑制されるため、板状部材１０から接合部３０側への熱引きによる板状部材１０の温度低下を、より効果的に抑制することができる。 Further, in the present embodiment, the average grain size of the circular portion 32 is 10 μm or less in at least one cross section of the joint portion 30 (second condition above). As a result, according to the present embodiment, heat radiation from the joint portion 30 is suppressed compared to the configuration in which the circular portion 32 has an average grain size of more than 10 μm. A decrease in the temperature of the plate member 10 due to heat dissipation can be suppressed more effectively.

また、本実施形態では、接合部３０の少なくとも１つの断面において、多孔質体の気孔率は、１０％以上、５０％以下である（上記第３の条件）。これにより、本実施形態によれば、多孔質体の気孔率が１０％未満である構成に比べて、接合部３０の熱伝導率が低いため、板状部材１０からベース部材２０への熱引きによる板状部材１０の温度低下を、より効果的に抑制することができる。また、本実施形態によれば、多孔質体の気孔率が５０％より高い構成に比べて、気孔率に起因する板状部材１０とベース部材２０との接合強度の低下を抑制することができる。 Further, in the present embodiment, the porosity of the porous body is 10% or more and 50% or less in at least one cross section of the joint portion 30 (third condition above). As a result, according to the present embodiment, the thermal conductivity of the joint portion 30 is lower than that of the porous body having a porosity of less than 10%. It is possible to more effectively suppress the temperature drop of the plate-like member 10 due to the above. In addition, according to the present embodiment, it is possible to suppress a decrease in bonding strength between the plate-like member 10 and the base member 20 due to the porosity, compared to a configuration in which the porosity of the porous body is higher than 50%. .

また、本実施形態では、接合部３０は、主成分として、粒径が１００ｎｍ以下の金属超微粒子を含んでいるため、接合部が主成分として樹脂や半田を含む構成に比べて、接合部３０の耐熱性を向上させることができる。例えば、接合部３０が、Ａｇナノ粒子により形成された構成では、接合部３０の融点は約９６０℃である。また、接合部３０では、２００℃程度で接合が可能であるため、接合時における残留応力を最小限に抑えることができる。また、特に、接合部３０が軟質性を有するＡｇやＣｕの金属超微粒子により形成された構成では、板状部材１０とベース部材２０との熱膨張差による応力を緩和する応力緩和性を、より効果的に向上させることができる。 In addition, in the present embodiment, since the joint 30 contains ultrafine metal particles having a particle size of 100 nm or less as a main component, the joint 30 is less likely to contain resin or solder as a main component. can improve the heat resistance of For example, in a configuration in which the joint 30 is formed of Ag nanoparticles, the melting point of the joint 30 is about 960.degree. In addition, since the bonding portion 30 can be bonded at about 200° C., residual stress at the time of bonding can be minimized. In particular, in a configuration in which the joint portion 30 is formed of Ag or Cu metal ultrafine particles having softness, the stress relaxation property for relaxing the stress due to the difference in thermal expansion between the plate-like member 10 and the base member 20 can be improved. can be effectively improved.

Ａ－５．性能評価：
図６は、各サンプルにおける接合部の断熱性と耐熱性とに関する評価結果を示す説明図である。図６に示すように、接合体の１１つのサンプルについて、接合部の断熱性と耐熱性とに関する評価を行った。１１つのサンプルは、全体として、上述の静電チャック１００と略同一構成であり、具体的には、アルミナにより形成された矩形状の板状部材と、Ａｌ合金により形成された矩形状のベース部材と、接合部とを備える接合体である。但し、各サンプルは、例えばサイズや、板状部材がヒータ電極５０等を備えない等の点で、上述の静電チャック１００とは異なる。板状部材にはメタライズ層が形成されており、メタライズ層とベース部材とが、主成分としてＡｇナノ粒子を含む接合部によって接合されている。なお、各サンプルは、上述した製造方法と同様の方法により製造できる。 A-5. Performance evaluation:
FIG. 6 is an explanatory diagram showing the evaluation results regarding the thermal insulation and heat resistance of the joints in each sample. As shown in FIG. 6, eleven samples of the joined body were evaluated for thermal insulation and heat resistance of the joint. The eleven samples generally had substantially the same configuration as the electrostatic chuck 100 described above, specifically, a rectangular plate member made of alumina and a rectangular base member made of Al alloy. and a joint. However, each sample differs from the above-described electrostatic chuck 100 in, for example, the size and the fact that the plate member does not include the heater electrode 50 or the like. A metallized layer is formed on the plate member, and the metallized layer and the base member are joined by a joint containing Ag nanoparticles as a main component. Each sample can be manufactured by a method similar to the manufacturing method described above.

サンプル１～３と、サンプル４～１１とは、接合部の前駆体（形成材料）および形態（構造）の少なくとも一方が互いに異なる。具体的には、サンプル１では、接合部の前駆体は樹脂であり、形態は緻密体である。サンプル２では、接合部の前駆体はＡｇロウ材であり、形態は緻密体であり、サンプル３では、接合部の前駆体はＡｇロウ材であり、形態は多孔質体である。すなわち、サンプル１～３における接合部は、上述の第１の条件を満たさない。一方、サンプル４～１１では、接合部の前駆体はＡｇナノ粒子であり、形態はＡｇナノ粒子（円状粒子）同士が固相拡散接合したＡｇナノ粒子接合体である。ただし、サンプル４における接合部は、接続部分を有しておらず、第１の条件を満たさず、サンプル５～１１における接合部は、第１の条件を満たす。また、サンプル５～１１では、接合部の円状部分の平均粒径と接合部（多孔質体）の気孔率との少なくとも一方が互いに異なる。なお、各サンプルにおける接合部の円状部分の平均粒径と接合部の気孔率とは、上述したペーストから接合部を形成するための熱処理における加熱温度と、熱処理における加熱時間と、Ａｇナノ粒子の粒径との少なくとも１つを変えることにより調整することができる。具体的には、熱処理における加熱温度を高くするほど、加熱時間を長くするほど、また、Ａｇナノ粒子の粒径が大きいほど、円状部分の平均粒径を大きくでき、また、接合部の気孔率を高くすることができる。 Samples 1 to 3 and samples 4 to 11 differ from each other in at least one of the precursor (formation material) and the form (structure) of the joint. Specifically, in sample 1, the precursor of the joint portion is a resin, and the form is a dense body. In sample 2, the precursor of the joint is Ag brazing material and has a dense body, and in sample 3, the precursor of the joint is Ag brazing material and has a porous body. That is, the joints in samples 1 to 3 do not satisfy the first condition described above. On the other hand, in samples 4 to 11, the precursor of the bonding portion was Ag nanoparticles, and the form was an Ag nanoparticle bonded body in which Ag nanoparticles (circular particles) were solid-phase diffusion bonded to each other. However, the joint in sample 4 does not have a connecting portion and does not satisfy the first condition, and the joints in samples 5 to 11 satisfy the first condition. Moreover, in samples 5 to 11, at least one of the average particle size of the circular portion of the joint and the porosity of the joint (porous body) is different from each other. The average particle size of the circular portion of the joint and the porosity of the joint in each sample are determined by the heating temperature in the heat treatment for forming the joint from the paste described above, the heating time in the heat treatment, and the Ag nanoparticles. can be adjusted by changing at least one of the particle size of Specifically, the higher the heating temperature in the heat treatment, the longer the heating time, and the larger the particle size of the Ag nanoparticles, the larger the average particle size of the circular portion. rate can be increased.

なお、各サンプルにおける接合部の形態、円状部分の平均粒径や接合部（多孔質体）の気孔率については、次のようにして特定する。まず、各サンプルの接合体の４つの角部を切り出して、その切り出された角部の切断面を研磨し、電子顕微鏡により例えば２０，０００倍の倍率で断面観察し、上述した方法により円状部分の平均粒径や接合部の気孔率を特定する。 The shape of the joint portion, the average particle size of the circular portion, and the porosity of the joint portion (porous body) in each sample are specified as follows. First, four corners of the bonded body of each sample were cut out, the cut surfaces of the cut corners were polished, and the cross section was observed with an electron microscope at a magnification of, for example, 20,000. Specify the average grain size of the part and the porosity of the joint.

接合部の断熱性は、次のようにして評価した。まず、各サンプルの接合体について、板状部材の吸着面に対して、３５０℃の加熱処理を施し続け、加熱開始から３分後におけるベース部材の表面温度を、熱電対等で測定した。図６中の断熱性では、「×」は、加熱開始３分後におけるベース部材の表面温度が１００℃以上になったことを意味し、「△」は、加熱開始３分後におけるベース部材の表面温度が８０℃以上、１００℃未満であったことを意味し、「○」は、加熱開始３分後におけるベース部材の表面温度が６０℃以上、８０℃未満であったことを意味し、「◎」は、加熱開始３分後におけるベース部材の表面温度が６０℃未満であったことを意味する。 The heat insulating property of the joint was evaluated as follows. First, for each sample joined body, the adsorption surface of the plate member was continuously subjected to heat treatment at 350° C., and the surface temperature of the base member was measured with a thermocouple or the like 3 minutes after the start of heating. In the heat insulating property in FIG. 6, "x" means that the surface temperature of the base member reached 100 ° C. or higher 3 minutes after the start of heating, and "Δ" means that the surface temperature of the base member was 3 minutes after the start of heating. It means that the surface temperature was 80 ° C. or more and less than 100 ° C., "○" means that the surface temperature of the base member was 60 ° C. or more and less than 80 ° C. 3 minutes after the start of heating, "A" means that the surface temperature of the base member was less than 60°C 3 minutes after the start of heating.

接合部の耐熱性は、次のようにして評価した。まず、各サンプルの接合体に対して、大気中で、３５０℃の加熱処理を１０時間行った。その後、各サンプルについて、接合体の破断の有無や、加熱処理の前後の重量差から、熱による接合部の分解の有無を確認した。図６中の耐熱性では、「×」は、接合部の分解が確認されたことを意味し、「○」は、接合部の分解が確認されなかったことを意味する。 The heat resistance of the joint was evaluated as follows. First, the joined body of each sample was subjected to heat treatment at 350° C. in the air for 10 hours. After that, for each sample, it was confirmed whether or not the joined body was broken, and whether or not the joined portion was decomposed by heat based on the weight difference before and after the heat treatment. In the heat resistance in FIG. 6, "x" means that decomposition of the joint was confirmed, and "o" means that decomposition of the joint was not confirmed.

図６に示すように、断熱性に関する評価結果について、サンプル１では、加熱処理において接合部が分解したため、断熱性を評価することができなかった。サンプル２～４では、加熱開始３分後におけるベース部材の表面温度は１００℃以上であり、サンプル５～１１では、加熱開始３分後におけるベース部材の表面温度は１００℃未満であった。このことは、接合部が円状部分と接続部分とから構成される形状であること（第１の条件を満たす）により、接合部の断熱性が向上し、板状部材からベース部材への熱引きを抑制することができることを意味する。また、サンプル７，９，１１では、円状部分の平均粒径が１０μｍより大きく、加熱開始３分後におけるベース部材の表面温度は８０℃以上であり、サンプル５，６，８，１０では、加熱開始３分後におけるベース部材の表面温度は未満８０℃未満であった。このことは、円状部分の平均粒径が１０μｍ以下であることにより、板状部材からベース部材への熱引きを、より効果的に抑制することができることを意味する。さらに、サンプル８では、円状部分の平均粒径が１未満であることにより、接合部の耐熱性がさらに向上しており、その結果、加熱開始３分後におけるベース部材の表面温度が６０℃未満になっている。 As shown in FIG. 6, regarding the evaluation results regarding heat insulation, in Sample 1, the joint portion was decomposed during the heat treatment, so the heat insulation could not be evaluated. In Samples 2-4, the surface temperature of the base member was 100° C. or higher 3 minutes after the start of heating, and in Samples 5-11, the surface temperature of the base member was less than 100° C. 3 minutes after the start of heating. This is because the joint has a shape composed of a circular portion and a connecting portion (satisfying the first condition), so that the heat insulating properties of the joint are improved and heat is transferred from the plate member to the base member. It means that the pull can be suppressed. In samples 7, 9, and 11, the average particle size of the circular portion was greater than 10 μm, and the surface temperature of the base member was 80° C. or higher 3 minutes after the start of heating. The surface temperature of the base member 3 minutes after the start of heating was less than 80°C. This means that heat transfer from the plate member to the base member can be more effectively suppressed when the average particle size of the circular portion is 10 μm or less. Furthermore, in sample 8, since the average grain size of the circular portion is less than 1, the heat resistance of the joint is further improved. is less than

図６に示すように、耐熱性に関する評価結果について、サンプル１では、接合部の分解が検出され、サンプル２～１１では、接合部の分解が検出されなかった。このことは、接合部が樹脂製の緻密体であるため、十分な耐熱性を得ることができないことを意味する。一方、接合部がＡｇナノ粒子接合体である構成では、接合部がＡｇロウ材の緻密体や多孔質体である構成に対して、同等レベルの耐熱性を確保できることを意味する。なお、接合部による接合強度に関する評価結果については、サンプル５～１１について、接合部の気孔率は１０％以上、５０％以下であり、接合部による十分な接合強度が確保できることが確認された。 As shown in FIG. 6, regarding the heat resistance evaluation results, in sample 1, decomposition of the joint was detected, and in samples 2 to 11, decomposition of the joint was not detected. This means that sufficient heat resistance cannot be obtained because the joint is a dense body made of resin. On the other hand, in the structure in which the joint portion is the Ag nanoparticle joined body, it means that the same level of heat resistance can be ensured as in the structure in which the joint portion is a dense body or porous body of Ag brazing material. Regarding the evaluation results regarding the joint strength at the joint, the porosity of the joint was 10% or more and 50% or less for samples 5 to 11, and it was confirmed that sufficient joint strength could be secured at the joint.

Ｂ．変形例：
本明細書で開示される技術は、上述の実施形態に限られるものではなく、その要旨を逸脱しない範囲において種々の形態に変形することができ、例えば次のような変形も可能である。 B. Variant:
The technology disclosed in this specification is not limited to the above-described embodiments, and can be modified in various forms without departing from the scope of the invention. For example, the following modifications are possible.

上記実施形態における静電チャック１００の構成は、あくまで一例であり、種々変形可能である。例えば、上記実施形態では、第１の部材および第２の部材として、板状の板状部材１０やベース部材２０を例示したが、板状以外の形状（例えば円筒状）の部材であってもよい。また、静電チャック１００は、上記第２の条件および第３の条件の少なくとも１つを満たさなくてもよい。 The configuration of the electrostatic chuck 100 in the above embodiment is merely an example, and various modifications are possible. For example, in the above embodiment, the plate-like plate-like member 10 and the base member 20 are illustrated as the first member and the second member. good. Also, the electrostatic chuck 100 does not have to satisfy at least one of the second condition and the third condition.

上記実施形態では、板状部材１０の内部にヒータ電極５０が１つ配置されているが、板状部材１０の内部にヒータ電極５０が複数配置されていてもよい。また、上記実施形態では、ベース部材２０に冷媒流路２１が形成されているが、必ずしもベース部材２０に冷媒流路２１が形成されている必要はない。 Although one heater electrode 50 is arranged inside the plate member 10 in the above embodiment, a plurality of heater electrodes 50 may be arranged inside the plate member 10 . Further, in the above embodiment, the coolant channel 21 is formed in the base member 20 , but the coolant channel 21 does not necessarily have to be formed in the base member 20 .

上記実施形態では、板状部材１０の内部に１つのチャック電極４０が設けられた単極方式が採用されているが、板状部材１０の内部に一対のチャック電極４０が設けられた双極方式が採用されてもよい。また、上記実施形態において、メタライズ層６０を備えず、板状部材１０と接合部３０とがメタライズ層６０を介さずに接合されている構成であってもよい。また、上記実施形態において、接合部３０は、第１の接合部と、該第１の接合部とベース部材２０との間に配置されている第２の接合部と、を含み、第１の接合部と第２の接合部との間に金属部を備える構成であってもよい。金属部の熱伝導率は、第１の接合部および第２の接合部の熱伝導率より低い。これにより、第１の接合部と第２の接合部に金属部を備えない構成に比べて、板状部材１０からベース部材２０への熱引きによる板状部材１０の温度低下を、より効果的に抑制することができる。なお、金属部は単層でも複数層であってもよく、また、金属部を構成する金属は非磁性であることが好ましい。金属部の例としては、Ａｌ(合金)箔、Ｔｉ(合金)箔、Ｃｕ(合金)箔、Ａｌ(合金)多孔質体、Ｔｉ(合金)多孔質体、Ｃｕ(合金)多孔質体である。 In the above-described embodiment, a monopolar system in which one chuck electrode 40 is provided inside the plate member 10 is adopted, but a bipolar system in which a pair of chuck electrodes 40 are provided inside the plate member 10 is adopted. may be adopted. Further, in the above embodiment, the metallized layer 60 may not be provided, and the plate member 10 and the joint portion 30 may be joined without the metallized layer 60 interposed therebetween. Further, in the above embodiment, the joint portion 30 includes a first joint portion and a second joint portion disposed between the first joint portion and the base member 20. A configuration in which a metal portion is provided between the joint portion and the second joint portion may be employed. The thermal conductivity of the metal portion is lower than the thermal conductivity of the first joint and the second joint. As a result, the temperature drop of the plate-like member 10 due to heat transfer from the plate-like member 10 to the base member 20 can be more effectively reduced than in the case where the first joint portion and the second joint portion are not provided with metal portions. can be suppressed to The metal part may have a single layer or multiple layers, and the metal forming the metal part is preferably non-magnetic. Examples of the metal part include Al (alloy) foil, Ti (alloy) foil, Cu (alloy) foil, Al (alloy) porous body, Ti (alloy) porous body, and Cu (alloy) porous body. .

上記実施形態の静電チャック１００における各部材の形成材料は、あくまで一例であり、任意に変更可能である。例えば、上記実施形態では、ベース部材２０が、金属により形成されているが、ベース部材２０が、金属以外の材料（例えば、樹脂材料、セラミックス）により形成されるとしてもよい。また、第２の部材の熱膨張係数は、第１の部材の熱膨張係数と同じであってもよい。また、接合部３０は、多孔質体であればよく、金属超微粒子以外の材料（例えば、樹脂、粒径が１００ｎｍより大きい金属粒子）により形成されたものでもよい。また、接合部３０は、主成分とは異なる種類の金属ナノ粒子（Ａｇ、Ｃｕ、Ａｕ、Ｐｔ、Ｐｄ）を微量添加してもよい。 The forming material of each member in the electrostatic chuck 100 of the above-described embodiment is merely an example, and can be arbitrarily changed. For example, in the above embodiment, the base member 20 is made of metal, but the base member 20 may be made of a material other than metal (for example, resin material, ceramics). Also, the coefficient of thermal expansion of the second member may be the same as the coefficient of thermal expansion of the first member. In addition, the joint portion 30 may be a porous body, and may be formed of a material other than ultrafine metal particles (for example, resin, metal particles with a particle size larger than 100 nm). In addition, a small amount of metal nanoparticles (Ag, Cu, Au, Pt, Pd) different from the main component may be added to the joint 30 .

また、接合部３０が主成分としてＡｇナノ粒子を含む場合、Ａｇと固相で相互拡散が生じやすい元素（状態図において相互に固溶相領域が多い元素Ａｇ、Ｃｕ、Ａｕ、Ｐｔ、Ｐｂ、Ｎｉ－Ａｕフラッシュなど）を、メタライズ層６０の最外層にすることが好ましい。また、上記実施形態において、ベース部材２０がＣｕではなく、例えばＦｅ系材料、Ｔｉ合金、Ａｌ合金により形成されている場合、同金属と接合部３０に含まれるＡｇナノ粒子との相互拡散が起こりにくい。この場合、ベース部材２０の上面Ｓ３にもメタライズ層を形成し、該メタライズ層と接合部との界面について、上述の第１の条件、第２の条件や第３の条件を満たすことが好ましい。 In addition, when the joint portion 30 contains Ag nanoparticles as a main component, elements that tend to cause mutual diffusion between Ag and the solid phase (elements that have a large mutual solid solution phase region in the phase diagram: Ag, Cu, Au, Pt, Pb, Ni—Au flash, etc.) is preferably the outermost layer of the metallization layer 60 . Further, in the above embodiment, if the base member 20 is not made of Cu but is made of, for example, an Fe-based material, a Ti alloy, or an Al alloy, interdiffusion between the metal and Ag nanoparticles contained in the joint 30 occurs. Hateful. In this case, it is preferable that a metallized layer is also formed on the upper surface S3 of the base member 20, and the interface between the metallized layer and the joint portion satisfies the above-described first, second and third conditions.

上記実施形態の静電チャック１００の製造方法は、あくまで一例であり、種々変形可能である。 The manufacturing method of the electrostatic chuck 100 of the above embodiment is merely an example, and various modifications are possible.

１０：板状部材１６：孔２０：ベース部材２１：冷媒流路２５，２６，３５，３６：孔３０：接合部３２：円状部分３３：連続部分３４：接続部分４０：チャック電極５０：ヒータ電極６０：メタライズ層１００：静電チャック１３１：第１のガス流路孔１３２：第２のガス流路孔１３３：横流路１３４：拡径部１４０：ピン挿通孔１６０：充填部材Ｌ：直線線分Ｐ：気孔Ｓ１：吸着面Ｓ２，Ｓ４，Ｓ５：下面Ｓ３：上面Ｗ：ウェハ 10: plate member 16: hole 20: base member 21: refrigerant flow path 25, 26, 35, 36: hole 30: joint portion 32: circular portion 33: continuous portion 34: connection portion 40: chuck electrode 50: heater Electrode 60: Metallized layer 100: Electrostatic chuck 131: First gas channel hole 132: Second gas channel hole 133: Horizontal channel 134: Expanded diameter portion 140: Pin insertion hole 160: Filling member L: Straight wire Minute P: pore S1: adsorption surface S2, S4, S5: lower surface S3: upper surface W: wafer

Claims

a first member made of ceramics, having a first surface substantially perpendicular to a first direction and a second surface opposite to the first surface;
a chuck electrode provided on the first member;
a heating resistor provided on the first member;
It has a third surface, the third surface is positioned on the second surface side of the first member, and has a thermal conductivity higher than that of the first member. a second member;
a joining portion disposed between the second surface of the first member and the third surface of the second member to join the first member and the second member;
An electrostatic chuck for holding an object on the first surface of the first member, comprising:
The joint portion is formed of a porous body having a higher porosity than the first member and the second member,
The porous body includes a plurality of circular portions having a substantially circular shape in at least one cross section substantially parallel to the first direction, and a plurality of circular portions narrower than the circular portions and adjacent to each other. a connection portion connecting the circular portions to each other ; and
The porous body contains Ag nanoparticles or Cu nanoparticles as a main component,
An electrostatic chuck characterized by:

The electrostatic chuck of claim 1, wherein
In the at least one cross section, the circular portion has an average particle size of 10 μm or less.
An electrostatic chuck characterized by:

In the electrostatic chuck according to claim 1 or claim 2,
In the at least one cross section, the porous body has a porosity of 10% or more and 50% or less.
An electrostatic chuck characterized by:

In the electrostatic chuck according to any one of claims 1 to 3,
the joint includes a first joint and a second joint disposed between the first joint and the second member;
The electrostatic chuck is further disposed between the first joint and the second joint and has a thermal conductivity lower than the thermal conductivity of the first joint and the second joint. comprising a metal part mainly composed of a metal having conductivity,
An electrostatic chuck characterized by:

a first member made of ceramics, having a first surface substantially perpendicular to a first direction and a second surface opposite to the first surface;
a chuck electrode provided on the first member;
a heating resistor provided on the first member;
It has a third surface, the third surface is arranged to be located on the second surface side of the first member, and has a thermal conductivity higher than that of the first member. a second member;
a joining portion disposed between the second surface of the first member and the third surface of the second member to join the first member and the second member;
An electrostatic chuck for holding an object on the first surface of the first member, comprising:
The joint portion is formed of a porous body having a higher porosity than the first member and the second member,
The porous body includes a plurality of circular portions having a substantially circular shape in at least one cross section substantially parallel to the first direction, and a plurality of circular portions narrower than the circular portions and adjacent to each other. a connection portion connecting the circular portions to each other; and
the joint includes a first joint and a second joint disposed between the first joint and the second member;
The electrostatic chuck is further disposed between the first joint and the second joint and has a thermal conductivity lower than the thermal conductivity of the first joint and the second joint. comprising a metal part mainly composed of a metal having conductivity,
An electrostatic chuck characterized by: