JP7628882B2

JP7628882B2 - Retaining device

Info

Publication number: JP7628882B2
Application number: JP2021082533A
Authority: JP
Inventors: 太一岐部
Original assignee: NGK Spark Plug Co Ltd
Current assignee: Niterra Co Ltd
Priority date: 2021-05-14
Filing date: 2021-05-14
Publication date: 2025-02-12
Anticipated expiration: 2041-05-14
Also published as: JP2022175820A

Description

本開示は、対象物を保持する保持装置に関する。 This disclosure relates to a holding device for holding an object.

対象物を保持面に保持する第１部材と、接合層を介して第１部材に接合された第２部材とを備える保持装置が知られている。この種の保持装置では、プラズマやプロセスガスにより接合層が劣化するおそれがあるため、接合層の外周面を保護する対策が施されている。例えば、特許文献１に記載されたウェハ支持部材（保持装置）では、接着層（接合層）の周辺部に凹部を形成し、凹部内にその壁面を押圧するように環状の保護部材を配置して、この保護部材により接着層へのプラズマやプロセスガスの侵入を防止するようにしている。 A holding device is known that includes a first member that holds an object on a holding surface and a second member that is bonded to the first member via a bonding layer. In this type of holding device, measures are taken to protect the outer peripheral surface of the bonding layer because there is a risk of the bonding layer being deteriorated by plasma or process gas. For example, in the wafer support member (holding device) described in Patent Document 1, a recess is formed on the periphery of the adhesive layer (bonding layer), and an annular protective member is placed inside the recess so as to press against the wall surface, and this protective member prevents the plasma or process gas from penetrating the adhesive layer.

特開２００６－８０３８９号公報JP 2006-80389 A

しかしながら、上記の保持装置では、保護部材と接合層との熱膨張率差に起因して、保護部材と接合層との間に空隙が生じるおそれがある。また、保護部材の封止性を高めるには、保護部材として伸縮性の高い材質を使用する必要があるが、保護部材もプラズマやプロセスガスにより劣化するため、保護部材の伸縮性が低下して、保護部材と接合層との間に空隙が生じるおそれもある。さらに、保護部材を凹部に配置したときに保護部材がねじれたり傾いたりして、保護部材と接合層との間に空隙が生じるおそれもある。そして、保護部材と接合層との間に空隙が生じると、その空隙にプラズマやプロセスガスが侵入して接合層を劣化させてしまう。 However, in the above-mentioned holding device, there is a risk of a gap occurring between the protective member and the bonding layer due to the difference in thermal expansion coefficient between the protective member and the bonding layer. In addition, to improve the sealing performance of the protective member, it is necessary to use a highly elastic material for the protective member, but since the protective member is also deteriorated by plasma and process gas, the elasticity of the protective member may decrease, and a gap may occur between the protective member and the bonding layer. Furthermore, when the protective member is placed in the recess, the protective member may twist or tilt, causing a gap to occur between the protective member and the bonding layer. And if a gap occurs between the protective member and the bonding layer, plasma or process gas may enter the gap and deteriorate the bonding layer.

そこで、本開示は上記した問題点を解決するためになされたものであり、接合層の外周面付近にプラズマやプロセスガスが侵入することを防止することができる保持装置を提供することを目的とする。 Therefore, this disclosure has been made to solve the above-mentioned problems, and aims to provide a holding device that can prevent plasma or process gas from penetrating near the outer peripheral surface of the bonding layer.

上記課題を解決するためになされた本開示の一形態は、
第１の面と、前記第１の面とは第１の方向にて反対側に設けられる第２の面とを備える第１部材と、
第３の面と、前記第３の面とは前記第１の方向にて反対側に設けられる第４の面とを備える第２部材と、
前記第１部材の前記第２の面と前記第２部材の前記第３の面との間に配置され、前記第１部材と前記第２部材とを接合する接合層とを備え、
前記第１部材の前記第１の面上に対象物を保持する保持装置において、
前記接合層の外周面全域を覆うように配置された内側保護部材と、
前記内側保護部材より外側に配置され、前記第１の方向における寸法が、前記内側保護部材より大きい外側保護部材とを有し、
前記外側保護部材は、前記内側保護部材の外周面全域を覆うように配置されていることを特徴とする。 In order to solve the above problems, one aspect of the present disclosure is to
A first member including a first surface and a second surface provided on an opposite side to the first surface in a first direction;
a second member including a third surface and a fourth surface provided on an opposite side of the third surface in the first direction;
a bonding layer disposed between the second surface of the first member and the third surface of the second member, bonding the first member and the second member;
A holding device for holding an object on the first surface of the first member,
An inner protective member arranged to cover the entire outer circumferential surface of the bonding layer;
an outer protective member disposed outside the inner protective member and having a dimension in the first direction larger than that of the inner protective member;
The outer protective member is disposed so as to cover the entire outer peripheral surface of the inner protective member.

この保持装置では、内側保護部材よりも第１の方向（保持装置の厚み方向）の寸法が大きい外側保護部材を、内側保護部材を覆うように配置しているため、内側保護部材にねじれや傾きが発生することを防止することができる。これにより、内側保護部材で接合層の外周面全域を確実に覆うことができる。従って、内側保護部材と外側保護部材とにより、接合層の外周面付近にプラズマやプロセスガスが侵入することを防止することができる。なお、仮に内側保護部材がずれて配置されたとしても、外側保護部材が内側保護部材を覆っているため、外側保護部材により、接合層の外周面付近へのプラズマやプロセスガスの侵入を防止することができる。 In this holding device, the outer protective member, which has a larger dimension in the first direction (thickness direction of the holding device) than the inner protective member, is arranged to cover the inner protective member, thereby preventing the inner protective member from twisting or tilting. This ensures that the entire outer peripheral surface of the bonding layer is covered by the inner protective member. Therefore, the inner protective member and the outer protective member can prevent plasma and process gas from entering near the outer peripheral surface of the bonding layer. Note that even if the inner protective member is positioned out of alignment, the outer protective member covers the inner protective member, so the outer protective member can prevent plasma and process gas from entering near the outer peripheral surface of the bonding layer.

上記した保持装置において、
前記第１部材の前記第２の面側における外周部、及び前記第２部材の前記第３の面側における外周部にはそれぞれ、前記内側保護部材を配置するための第１段部と、前記外側保護部材を配置するための第２段部とが形成されており、
前記内側保護部材は、前記第１部材の前記第１段部の側面と、前記第２部材の前記第１段部の側面との両方に接触していることが好ましい。 In the above-mentioned holding device,
a first step for disposing the inner protective member and a second step for disposing the outer protective member are formed on an outer periphery of the first member on the second surface side and an outer periphery of the second member on the third surface side,
It is preferable that the inner protective member be in contact with both a side surface of the first step portion of the first member and a side surface of the first step portion of the second member.

このように、第１部材の第２の面側における外周部、及び第２部材の第３の面側における外周部に、内側保護部材を配置するための第１段部と、外側保護部材を配置するための第２段部とを設けることにより、内側保護部材と外側保護部材のそれぞれを位置ズレすることなく、適正な位置に配置することができる。このとき、内側保護部材によって接合層がしっかりと封止されているので、外側保護部材は、第１部材の第１段部の側面と第２部材の第２段部の側面とのうち、少なくとも一方に接触していればよい。これにより、接合層の外周面全域を確実に覆った状態の内側保護部材全体を外側保護部材で確実に覆うことができるため、内側保護部材によって接合層を確実に封止することができ、接合層へのプラズマやプロセスガスの侵入を防止することができる。 In this way, by providing a first step for arranging the inner protective member and a second step for arranging the outer protective member on the outer periphery of the second surface side of the first member and the outer periphery of the third surface side of the second member, the inner protective member and the outer protective member can be arranged in the appropriate position without misalignment. At this time, since the bonding layer is securely sealed by the inner protective member, the outer protective member only needs to be in contact with at least one of the side of the first step of the first member and the side of the second step of the second member. This allows the entire inner protective member, which reliably covers the entire outer periphery of the bonding layer, to be reliably covered by the outer protective member, so that the bonding layer can be reliably sealed by the inner protective member and the intrusion of plasma and process gas into the bonding layer can be prevented.

上記した保持装置において、
前記外側保護部材は、前記内側保護部材よりも伸縮性が高いものであることが好ましい。 In the above-mentioned holding device,
The outer protective member preferably has a higher elasticity than the inner protective member.

これにより、外側保護部材で内側保護部材を内側へ効果的に押圧することができるため、接合層を封止する内側保護部材の封止性能を高めることができる。そのため、接合層へのプラズマやプロセスガスの侵入を効果的に防止することができる。 This allows the outer protective member to effectively press the inner protective member inward, improving the sealing performance of the inner protective member that seals the bonding layer. This effectively prevents plasma and process gas from penetrating the bonding layer.

上記した保持装置において、
前記外側保護部材は、前記内側保護部材を前記第１の方向と直交する第２の方向における内側方向に押圧していることが好ましい。 In the above-mentioned holding device,
It is preferable that the outer protective member presses the inner protective member inwardly in a second direction perpendicular to the first direction.

これにより、内側保護部材と接合層との熱膨張率差に起因して、内側保護部材が、部分的にねじれたり、傾いたりすることを確実に防止することができ、外側保護部材で内側保護部材を内側へより効果的に押圧することができる。そのため、内側保護部材の封止性能を一層高めることができ、接合層へのプラズマやプロセスガスの侵入をより効果的に防止することができる。 This reliably prevents the inner protective member from being partially twisted or tilted due to the difference in thermal expansion coefficient between the inner protective member and the bonding layer, and allows the outer protective member to more effectively press the inner protective member inward. This further improves the sealing performance of the inner protective member, and more effectively prevents the intrusion of plasma and process gas into the bonding layer.

上記した保持装置において、
前記内側保護部材の外周面は、前記第１の方向と直交する第２の方向における外側方向へ凸となる円弧形状に形成されていることが好ましい。 In the above-mentioned holding device,
It is preferable that the outer peripheral surface of the inner protective member is formed in an arc shape that is convex outward in a second direction perpendicular to the first direction.

これにより、外側保護部材で内側保護部材を内側へより一層効果的に押圧することができるため、内側保護部材の封止性能をさらに高めることができる。そのため、接合層へのプラズマやプロセスガスの侵入をより一層効果的に防止することができる。 This allows the outer protective member to press the inner protective member inward more effectively, further improving the sealing performance of the inner protective member. This makes it possible to more effectively prevent the intrusion of plasma and process gas into the bonding layer.

本開示によれば、接合層の外周面付近にプラズマやプロセスガスが侵入することを防止することができる保持装置を提供することができる。 According to the present disclosure, it is possible to provide a holding device that can prevent plasma or process gas from penetrating near the outer peripheral surface of the bonding layer.

実施形態の静電チャックの概略斜視図である。1 is a schematic perspective view of an electrostatic chuck according to an embodiment; 実施形態の静電チャックのＸＺ断面の概略構成図である。1 is a schematic configuration diagram of an electrostatic chuck according to an embodiment of the present invention taken along an XZ cross section; 接合層の外周部付近を拡大したＸＺ断面の概略構成図である。4 is a schematic diagram of an enlarged XZ cross section of the bonding layer near its outer periphery. FIG. 変形例における接合層の外周部付近を拡大したＸＺ断面の概略構成図である。13 is a schematic configuration diagram of an enlarged XZ cross section of the vicinity of the outer periphery of a bonding layer in a modified example. FIG.

本開示に係る実施形態である保持装置について、図面を参照しながら詳細に説明する。本実施形態では、例えば、成膜装置（ＣＶＤ成膜装置やスパッタリング成膜装置など）やエッチング装置（プラズマエッチング装置など）といった半導体製造装置に使用される静電チャックを例示する。 A holding device according to an embodiment of the present disclosure will be described in detail with reference to the drawings. In this embodiment, an electrostatic chuck used in semiconductor manufacturing equipment such as a film forming apparatus (such as a CVD film forming apparatus or a sputtering film forming apparatus) or an etching apparatus (such as a plasma etching apparatus) will be described as an example.

本実施形態の静電チャック１について、図１～図３を参照しながら説明する。本実施形態の静電チャック１は、半導体ウエハＷ（対象物）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半導体ウエハＷを固定するために使用される。図１、図２に示すように、静電チャック１は、板状部材１０と、ベース部材２０と、板状部材１０とベース部材２０とを接合する接合層４０と、内側保護部材５０および外側保護部材６０を有する。なお、板状部材１０は本開示の「第１部材」の一例であり、ベース部材２０は本開示の「第２部材」の一例である。 The electrostatic chuck 1 of this embodiment will be described with reference to Figs. 1 to 3. The electrostatic chuck 1 of this embodiment is a device that attracts and holds a semiconductor wafer W (object) by electrostatic attraction, and is used, for example, to fix the semiconductor wafer W in a vacuum chamber of a semiconductor manufacturing device. As shown in Figs. 1 and 2, the electrostatic chuck 1 has a plate-shaped member 10, a base member 20, a bonding layer 40 that bonds the plate-shaped member 10 and the base member 20, an inner protective member 50, and an outer protective member 60. The plate-shaped member 10 is an example of a "first member" in this disclosure, and the base member 20 is an example of a "second member" in this disclosure.

以下の説明においては、説明の便宜上、図１に示すようにＸＹＺ軸を定義する。ここで、Ｚ軸は、静電チャック１の軸線方向（図１において上下方向）の軸であり、Ｘ軸とＹ軸は、静電チャック１の径方向の軸である。そして、Ｚ軸方向は、本開示の「第１の方向」の一例であり、Ｘ軸方向（Ｙ軸方向）は、本開示の「第２の方向」の一例である。 For ease of explanation, in the following description, the XYZ axes are defined as shown in FIG. 1. Here, the Z axis is the axis in the axial direction of the electrostatic chuck 1 (the vertical direction in FIG. 1), and the X and Y axes are the axes in the radial direction of the electrostatic chuck 1. The Z axis direction is an example of the "first direction" of the present disclosure, and the X axis direction (Y axis direction) is an example of the "second direction" of the present disclosure.

板状部材１０は、図１に示すように、円盤状の部材であり、セラミックスにより形成されている。セラミックスとしては、様々なセラミックスが用いられるが、強度や耐摩耗性、耐プラズマ性等の観点から、例えば、酸化アルミニウム（アルミナ、Ａｌ_２Ｏ_３）または窒化アルミニウム（ＡｌＮ）を主成分とするセラミックスが用いられることが好ましい。なお、ここでいう主成分とは、含有割合の最も多い成分（例えば、体積含有率が９０ｖｏｌ％以上の成分）を意味する。 As shown in Fig. 1, the plate-like member 10 is a disk-shaped member and is made of ceramics. Various ceramics can be used as the ceramics, but from the viewpoints of strength, wear resistance, plasma resistance, etc., it is preferable to use ceramics whose main component is, for example, aluminum oxide (alumina, _Al2O3 ₎ or aluminum nitride (AlN). Note that the main component here means the component with the highest content (for example, a component with a volume content of 90 vol% or more).

板状部材１０は、外周に沿って上側に切り欠きが形成された部分である外周部１０ａと、外周部１０ａの内側に位置する内側部１０ｂとから構成されている。板状部材１０における内側部１０ｂの厚さ（Ｚ軸方向における厚さであり、以下同様。）は、外周部１０ａに形成された切り欠きの分だけ、外周部１０ａの厚さより厚くなっている。すなわち、板状部材１０の外周部１０ａと内側部１０ｂとの境界の位置で、板状部材１０の厚さが変化している。 The plate-shaped member 10 is composed of an outer peripheral portion 10a, which is a portion with a notch formed on the upper side along the outer periphery, and an inner portion 10b located inside the outer peripheral portion 10a. The thickness of the inner portion 10b of the plate-shaped member 10 (thickness in the Z-axis direction, the same applies below) is thicker than the thickness of the outer peripheral portion 10a by the amount of the notch formed in the outer peripheral portion 10a. In other words, the thickness of the plate-shaped member 10 changes at the boundary between the outer peripheral portion 10a and the inner portion 10b of the plate-shaped member 10.

板状部材１０の内側部１０ｂ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の外周部１０ａの直径は、例えば６０ｍｍ～５１０ｍｍ程度（通常は２１０ｍｍ～３６０ｍｍ程度）である（ただし、外周部１０ａの直径は内側部１０ｂの直径より大きい）。また、板状部材１０の内側部１０ｂの厚さは、例えば１ｍｍ～１０ｍｍ程度であり、板状部材１０の外周部１０ａの厚さは、例えば０．５ｍｍ～９．５ｍｍ程度である（ただし、外周部１０ａの厚さは内側部１０ｂの厚さより薄い）。 The diameter of the inner part 10b of the plate-shaped member 10 is, for example, about 50 mm to 500 mm (usually about 200 mm to 350 mm), and the diameter of the outer periphery 10a of the plate-shaped member 10 is, for example, about 60 mm to 510 mm (usually about 210 mm to 360 mm) (however, the diameter of the outer periphery 10a is larger than the diameter of the inner part 10b). The thickness of the inner part 10b of the plate-shaped member 10 is, for example, about 1 mm to 10 mm, and the thickness of the outer periphery 10a of the plate-shaped member 10 is, for example, about 0.5 mm to 9.5 mm (however, the thickness of the outer periphery 10a is thinner than the thickness of the inner part 10b).

図１、図２に示すように、板状部材１０は、半導体ウエハＷを保持する保持面１１と、板状部材１０の厚み方向（Ｚ軸方向に一致する方向、上下方向）について保持面１１とは反対側に設けられる下面１２とを備えている。なお、外周部１０ａにおける上面（外周上面）は、例えば、静電チャック１を固定するための治具（不図示）が係合する。保持面１１は本開示の「第１の面」の一例であり、下面１２は本開示の「第２の面」の一例である。 As shown in Figures 1 and 2, the plate-like member 10 has a holding surface 11 that holds the semiconductor wafer W, and a bottom surface 12 that is provided on the opposite side of the holding surface 11 in the thickness direction of the plate-like member 10 (the direction that coincides with the Z-axis direction, the up-down direction). The top surface (outer peripheral top surface) of the outer periphery 10a engages with, for example, a jig (not shown) for fixing the electrostatic chuck 1. The holding surface 11 is an example of a "first surface" in the present disclosure, and the bottom surface 12 is an example of a "second surface" in the present disclosure.

板状部材１０の内部には、図２に示すように、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１３が配置されている。Ｚ軸方向視でのチャック電極１３の形状は、例えば略円形である。チャック電極１３に外部から電力が供給されると、静電引力が発生し、この静電引力によって半導体ウエハＷが板状部材１０の保持面１１に吸着保持される。 As shown in FIG. 2, a chuck electrode 13 made of a conductive material (e.g., tungsten, molybdenum, platinum, etc.) is disposed inside the plate-like member 10. The shape of the chuck electrode 13 as viewed in the Z-axis direction is, for example, substantially circular. When power is supplied to the chuck electrode 13 from the outside, electrostatic attraction is generated, and the semiconductor wafer W is attracted and held on the holding surface 11 of the plate-like member 10 by this electrostatic attraction.

また、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）を含む抵抗発熱体により構成されたヒータ電極１４が配置されている。ヒータ電極１４に外部から電力が供給されると、ヒータ電極１４が発熱することによって板状部材１０が加熱され、板状部材１０の保持面１１に保持された半導体ウエハＷが温められる。 A heater electrode 14 made of a resistance heating element containing a conductive material (e.g., tungsten, molybdenum, platinum, etc.) is disposed inside the plate-shaped member 10. When power is supplied to the heater electrode 14 from the outside, the heater electrode 14 generates heat, heating the plate-shaped member 10 and warming the semiconductor wafer W held on the holding surface 11 of the plate-shaped member 10.

そして、板状部材１０の外周部の下面１２側には、図３に示すように、内側保護部材５０が配置される円周状の第１段部３１と、第１段部３１の外側に設けられて外側保護部材６０が配置される第２段部３２が形成されている。第１段部３１は、Ｚ軸方向と略平行な側面３１ａと、Ｚ軸方向と略直交する底面３１ｂとを備え、断面Ｌ字状をなしている。同様に、第２段部３２は、Ｚ軸方向と略平行な側面３２ａと、Ｚ軸方向と略直交する底面３２ｂとを備え、断面Ｌ字状をなしている。 As shown in FIG. 3, on the underside 12 of the outer periphery of the plate-like member 10, a circumferential first step 31 on which the inner protective member 50 is disposed, and a second step 32 on the outside of the first step 31 on which the outer protective member 60 is disposed are formed. The first step 31 has a side surface 31a substantially parallel to the Z-axis direction and a bottom surface 31b substantially perpendicular to the Z-axis direction, and has an L-shaped cross section. Similarly, the second step 32 has a side surface 32a substantially parallel to the Z-axis direction and a bottom surface 32b substantially perpendicular to the Z-axis direction, and has an L-shaped cross section.

ベース部材２０は、図２に示すように、板状部材１０の外周部１０ａと同径（あるいは外周部１０ａより径が大きい）円柱状の部材である。このベース部材２０は、金属（例えば、アルミニウムやアルミニウム合金等）により形成されていることが好ましいが、金属以外であってもよい。そして、ベース部材２０は、上面２１と、ベース部材２０（板状部材１０）の中心軸方向（すなわち、Ｚ軸方向）について上面２１とは反対側に設けられる下面２２と、を備えている。なお、上面２１は本開示の「第３の面」の一例であり、下面２２は本開示の「第４の面」の一例である。 2, the base member 20 is a cylindrical member having the same diameter as the outer periphery 10a of the plate-like member 10 (or a larger diameter than the outer periphery 10a). The base member 20 is preferably made of a metal (e.g., aluminum or an aluminum alloy), but may be made of a material other than metal. The base member 20 has an upper surface 21 and a lower surface 22 provided on the opposite side of the upper surface 21 in the central axis direction (i.e., the Z-axis direction) of the base member 20 (plate-like member 10). The upper surface 21 is an example of a "third surface" in the present disclosure, and the lower surface 22 is an example of a "fourth surface" in the present disclosure.

なお、ベース部材２０の直径は、例えば２２０ｍｍ～５５０ｍｍ程度（通常は２２０ｍｍ～３５０ｍｍ）である。また、ベース部材２０の厚さは、例えば２０ｍｍ～４０ｍｍ程度である。 The diameter of the base member 20 is, for example, about 220 mm to 550 mm (usually 220 mm to 350 mm). The thickness of the base member 20 is, for example, about 20 mm to 40 mm.

また、ベース部材２０には、冷媒（例えば、フッ素系不活性液体や水等）を流すための冷媒流路２３が形成されている。そして、冷媒流路２３は、ベース部材２０の下面２２に設けられた不図示の供給口と排出口とに接続しており、供給口からベース部材２０に供給された冷媒が、冷媒流路２３内を流れて排出口からベース部材２０の外へ排出される。このようにして、ベース部材２０の冷媒流路２３内に冷媒を流すことにより、ベース部材２０が冷却され、これにより、接合層４０を介して板状部材１０が冷却される。 The base member 20 is also formed with a refrigerant flow path 23 for flowing a refrigerant (e.g., a fluorine-based inert liquid, water, etc.). The refrigerant flow path 23 is connected to a supply port and a discharge port (not shown) provided on the underside 22 of the base member 20, and the refrigerant supplied to the base member 20 from the supply port flows through the refrigerant flow path 23 and is discharged from the discharge port to the outside of the base member 20. In this way, the base member 20 is cooled by flowing the refrigerant through the refrigerant flow path 23 of the base member 20, and the plate-like member 10 is thereby cooled via the bonding layer 40.

そして、ベース部材２０の外周部の上面２１側には、図３に示すように、内側保護部材５０が配置される円周状の第１段部３５と、第１段部３５の外側に設けられて外側保護部材６０が配置される第２段部３６が形成されている。第１段部３５は、Ｚ軸方向と略平行な側面３５ａと、Ｚ軸方向と略直交する底面３５ｂとを備え、断面Ｌ字状をなしている。同様に、第２段部３６は、Ｚ軸方向と略平行な側面３６ａと、Ｚ軸方向と略直交する底面３６ｂとを備え、断面Ｌ字状をなしている。 As shown in FIG. 3, the upper surface 21 side of the outer periphery of the base member 20 is formed with a circumferential first step 35 on which the inner protective member 50 is disposed, and a second step 36 provided outside the first step 35 on which the outer protective member 60 is disposed. The first step 35 has a side surface 35a substantially parallel to the Z-axis direction and a bottom surface 35b substantially perpendicular to the Z-axis direction, and has an L-shaped cross section. Similarly, the second step 36 has a side surface 36a substantially parallel to the Z-axis direction and a bottom surface 36b substantially perpendicular to the Z-axis direction, and has an L-shaped cross section.

接合層４０は、板状部材１０の下面１２とベース部材２０の上面２１との間に配置され、板状部材１０とベース部材２０とを接合している。この接合層４０を介して、板状部材１０の下面１２とベース部材２０の上面２１とが熱的に接続されている。接合層４０は、例えばシリコーン系樹脂やアクリル系樹脂、エポキシ系樹脂等の接着材により構成されている。なお、接合層４０の厚さ（Ｚ軸方向の寸法）は、例えば０．１ｍｍ～１．０ｍｍ程度である。また、接合層４０の熱伝導率は、例えば１．０Ｗ／ｍＫである。なお、接合層４０（シリコーン系樹脂を想定）の熱伝導率は、０．１Ｗ／ｍＫ～２．０Ｗ／ｍＫ（好ましくは、０．５Ｗ／ｍＫ～１．５Ｗ／ｍＫ）の範囲内が望ましい。 The bonding layer 40 is disposed between the lower surface 12 of the plate-shaped member 10 and the upper surface 21 of the base member 20, and bonds the plate-shaped member 10 and the base member 20. The lower surface 12 of the plate-shaped member 10 and the upper surface 21 of the base member 20 are thermally connected via the bonding layer 40. The bonding layer 40 is made of an adhesive material such as silicone resin, acrylic resin, or epoxy resin. The thickness (dimension in the Z-axis direction) of the bonding layer 40 is, for example, about 0.1 mm to 1.0 mm. The thermal conductivity of the bonding layer 40 is, for example, 1.0 W/mK. The thermal conductivity of the bonding layer 40 (assuming silicone resin) is preferably within the range of 0.1 W/mK to 2.0 W/mK (preferably, 0.5 W/mK to 1.5 W/mK).

なお、本実施形態では、接合層４０の外周面４０ａの位置が、板状部材１０の第１段部３１の側面３１ａ、およびベース部材２０の第１段部３５の側面３５ａの位置に対して、ほぼ同一となっているが、内側に後退していてもよい。 In this embodiment, the position of the outer peripheral surface 40a of the bonding layer 40 is substantially the same as the position of the side surface 31a of the first step 31 of the plate-like member 10 and the side surface 35a of the first step 35 of the base member 20, but it may be recessed inward.

内側保護部材５０および外側保護部材６０は、プラズマやプロセスガスから接合層４０を保護するための部材である。内側保護部材５０は、その両端部が第１段部３１，３５に配置され、外側保護部材６０は、その両端部が第２段部３２，３６に配置されている。 The inner protective member 50 and the outer protective member 60 are members for protecting the bonding layer 40 from plasma and process gas. The inner protective member 50 has both ends disposed on the first step portions 31 and 35, and the outer protective member 60 has both ends disposed on the second step portions 32 and 36.

内側保護部材５０は、Ｚ軸方向視で略円環状の部材である。この内側保護部材５０は、エラストマー（例えば、合成ゴム等）や樹脂（例えば、フッ素樹脂等）により形成されている。なお、内側保護部材５０の形成材料は、弾性を有し、かつ、耐プラズマ性、耐熱性、耐薬品性に優れた材料であることが好ましい。内側保護部材５０の形成材料は、比較的柔らかい材料であることが好ましい。 The inner protective member 50 is a member having a substantially circular ring shape when viewed in the Z-axis direction. The inner protective member 50 is formed from an elastomer (e.g., synthetic rubber, etc.) or a resin (e.g., fluororesin, etc.). The material forming the inner protective member 50 is preferably a material that has elasticity and has excellent plasma resistance, heat resistance, and chemical resistance. The material forming the inner protective member 50 is preferably a relatively soft material.

内側保護部材５０のＺ軸方向（図３では上下方向）の寸法は、側面３１ａのＺ軸方向の寸法と接合層４０の厚みと側面３５ａのＺ軸方向の寸法との合計寸法にほぼ等しく、内側保護部材５０は、Ｚ軸方向の両端にて内周側が、側面３１ａおよび側面３５ａの両方に接触するとともに、Ｚ軸方向の両端が底面３１ｂ，３２ｂの両方に接触して、第１段部３１，３５内に配置されている。これにより、内側保護部材５０は、接合層４０の外周面４０ａ全域を覆っている。なお、内側保護部材５０は、Ｚ軸方向の両端部にて、側面３１ａおよび側面３５ａに接触していれば、内側保護部材５０のＺ軸方向の寸法は、上記合計寸法よりも小さくてもよい。また、内側保護部材５０のＺ軸方向の寸法は、例えば０．３ｍｍ～６．０ｍｍ程度であり、幅寸法（Ｘ軸又はＹ軸方向（図３では横方向）の寸法）は、例えば０．３ｍｍ～２．０ｍｍ程度である。 The dimension of the inner protective member 50 in the Z-axis direction (the vertical direction in FIG. 3) is approximately equal to the sum of the dimension of the side 31a in the Z-axis direction, the thickness of the bonding layer 40, and the dimension of the side 35a in the Z-axis direction, and the inner protective member 50 is disposed in the first step 31, 35 with the inner circumferential side in contact with both the side 31a and the side 35a at both ends in the Z-axis direction and both ends in the Z-axis direction in contact with both the bottom surfaces 31b, 32b. As a result, the inner protective member 50 covers the entire outer circumferential surface 40a of the bonding layer 40. Note that the dimension of the inner protective member 50 in the Z-axis direction may be smaller than the above-mentioned sum as long as the inner protective member 50 is in contact with the side 31a and the side 35a at both ends in the Z-axis direction. The dimension of the inner protective member 50 in the Z-axis direction is, for example, about 0.3 mm to 6.0 mm, and the width dimension (dimension in the X-axis or Y-axis direction (horizontal direction in FIG. 3)) is, for example, about 0.3 mm to 2.0 mm.

外側保護部材６０も、内側保護部材５０と同様、Ｚ軸方向視で略円環状の部材である。この外側保護部材６０は、例えばエラストマー（例えば、合成ゴムなど）や樹脂（例えば、フッ素樹脂等）により形成されている。なお、外側保護部材６０の形成材料は、弾性を有し、かつ、耐プラズマ性、耐熱性、耐薬品性に優れた材料であることが好ましく、外側保護部材６０は、内側保護部材５０よりも伸縮性が大きいものであることが好ましい。これにより、外側保護部材６０で内側保護部材５０を内側へ効果的に押圧することができるからである。なお、伸縮性は、引張試験の前後の寸法変化により弾性率を測定すればよい。具体的には、ＪＩＳＫ６２５１：２０１７、ＪＩＳＫ７１３７－２：２００１、ＪＩＳＫ７１６１－１２０１４等に基づいて測定する。また、外側保護部材６０は、内側保護部材５０よりも熱膨張率が小さいものであることが好ましい。これにより、内側保護部材５０と接合層４０（あるいは外側保護部材６０）との熱膨張率差に起因して、内側保護部材５０に部分的にねじれや傾きが発生したとしても、外側保護部材６０により、内側保護部材５０のねじれや傾きを修正することができるからである。また、伸縮性とは、元の形状に戻ろうとする性質（例えば、弾性）を指し、外側保護部材６０の弾性力が、内側保護部材５０の弾性力よりも大きければ、外側保護部材６０が内側保護部材５０を内側へ効果的に押圧することができる。 Like the inner protective member 50, the outer protective member 60 is also a substantially annular member when viewed in the Z-axis direction. The outer protective member 60 is formed of, for example, an elastomer (e.g., synthetic rubber, etc.) or a resin (e.g., fluororesin, etc.). The material forming the outer protective member 60 is preferably a material that has elasticity and excellent plasma resistance, heat resistance, and chemical resistance, and the outer protective member 60 is preferably one that is more elastic than the inner protective member 50. This is because the outer protective member 60 can effectively press the inner protective member 50 inward. The elasticity can be measured by measuring the elastic modulus based on the dimensional change before and after the tensile test. Specifically, it is measured based on JIS K 6251:2017, JIS K 7137-2:2001, JIS K 7161-1 2014, etc. In addition, it is preferable that the outer protective member 60 has a smaller thermal expansion coefficient than the inner protective member 50. This is because even if the inner protective member 50 is partially twisted or tilted due to the difference in thermal expansion coefficient between the inner protective member 50 and the bonding layer 40 (or the outer protective member 60), the outer protective member 60 can correct the twist or tilt of the inner protective member 50. In addition, stretchability refers to the property of returning to the original shape (e.g., elasticity), and if the elastic force of the outer protective member 60 is greater than the elastic force of the inner protective member 50, the outer protective member 60 can effectively press the inner protective member 50 inward.

外側保護部材６０のＺ軸方向（図３では上下方向）の寸法は、内側保護部材５０のＺ軸方向の寸法よりも大きく、外側保護部材６０は、Ｚ軸方向の両端にて内周側が側面３２ａおよび側面３６ａの両方に接触する一方、Ｚ軸方向の両端が底面３２ｂおよび底面３６ｂには接触せずに（外側保護部材６０と底面３２ｂ，３６ｂとの間に隙間が存在するように）、第２段部３２，３６内に配置されている。これにより、内側保護部材５０は、外側保護部材６０により覆われている。なお、本実施形態では、外側保護部材６０が、Ｚ軸方向の両端にて、側面３２ａおよび側面３６ａの両方に接触しているが、外側保護部材６０は、内側保護部材５０の外周面全域を覆っていればよいため、側面３２ａまたは側面３６ａの少なくとも一方に接触していればよい。また、外側保護部材６０のＺ軸方向の寸法は、例えば０．３ｍｍ～７．０ｍｍ程度であり、幅寸法（Ｘ軸又はＹ軸方向（図３では横方向）の寸法）は、例えば０．３ｍｍ～２．０ｍｍ程度である。 The dimension of the outer protective member 60 in the Z-axis direction (the vertical direction in FIG. 3) is larger than the dimension of the inner protective member 50 in the Z-axis direction, and the inner circumferential side of the outer protective member 60 contacts both the side surface 32a and the side surface 36a at both ends in the Z-axis direction, while both ends in the Z-axis direction do not contact the bottom surface 32b and the bottom surface 36b (so that there is a gap between the outer protective member 60 and the bottom surfaces 32b and 36b), and is disposed within the second step portion 32, 36. As a result, the inner protective member 50 is covered by the outer protective member 60. Note that in this embodiment, the outer protective member 60 contacts both the side surface 32a and the side surface 36a at both ends in the Z-axis direction, but since the outer protective member 60 only needs to cover the entire outer circumferential surface of the inner protective member 50, it is sufficient that the outer protective member 60 contacts at least one of the side surface 32a or the side surface 36a. The dimension of the outer protective member 60 in the Z-axis direction is, for example, about 0.3 mm to 7.0 mm, and the width dimension (dimension in the X-axis or Y-axis direction (horizontal direction in FIG. 3)) is, for example, about 0.3 mm to 2.0 mm.

この外側保護部材６０は、内側保護部材５０を内側方向（Ｚ軸方向視での静電チャック１の中心に向かう方向）に押圧している。なお、外側保護部材６０による内側保護部材５０の押圧は、例えば、設置前の外側保護部材６０のＺ軸方向視での大きさ（外径）を設置後の外側保護部材６０の大きさ（外径）より小さく設定し、外側保護部材６０を設置した際に外側保護部材６０に張力が生じるようにすることにより、実現することができる。 The outer protective member 60 presses the inner protective member 50 inward (toward the center of the electrostatic chuck 1 as viewed in the Z-axis direction). The pressing of the inner protective member 50 by the outer protective member 60 can be achieved, for example, by setting the size (outer diameter) of the outer protective member 60 as viewed in the Z-axis direction before installation smaller than the size (outer diameter) of the outer protective member 60 after installation, so that tension is generated in the outer protective member 60 when the outer protective member 60 is installed.

すなわち、外側保護部材６０が内側保護部材５０の外周を覆うように設置された状態において外側保護部材６０に張力が生じていれば、外側保護部材６０は内側保護部材５０を押圧することができる。また、内側保護部材５０の幅寸法（Ｘ軸又はＹ軸方向（図３では横方向）の寸法）が、底面３１ｂ，３５ｂの径方向（Ｘ軸又はＹ軸方向）の寸法より大きくしても、設置された状態の外側保護部材６０は内側保護部材５０を押圧することができる。そして、本実施形態では、内側保護部材５０よりも大きい外側保護部材６０が、外側保護部材６０と底面３２ｂ，３６ｂとの間に隙間が存在するように。第２段部３２，３６配置されている。そのため、外側保護部材６０が底面３２ｂ，３６ｂに接触して内側へ収縮する変形が阻害されることがない。従って、外側保護部材６０を第２段部３２，３６に配置した際、外側保護部材６０に発生する張力を減少させることがないため、外側保護部材６０によって内側保護部材５０をしっかりと押圧することができる。 That is, if tension is generated in the outer protective member 60 when the outer protective member 60 is installed so as to cover the outer periphery of the inner protective member 50, the outer protective member 60 can press the inner protective member 50. Also, even if the width dimension (dimension in the X-axis or Y-axis direction (horizontal direction in FIG. 3)) of the inner protective member 50 is larger than the radial dimension (X-axis or Y-axis direction) of the bottom surfaces 31b, 35b, the outer protective member 60 in the installed state can press the inner protective member 50. And, in this embodiment, the outer protective member 60, which is larger than the inner protective member 50, is arranged in the second step portion 32, 36 so that there is a gap between the outer protective member 60 and the bottom surfaces 32b, 36b. Therefore, the deformation of the outer protective member 60 contracting inward by contacting the bottom surfaces 32b, 36b is not hindered. Therefore, when the outer protective member 60 is placed on the second step portions 32, 36, the tension generated in the outer protective member 60 is not reduced, so the outer protective member 60 can firmly press against the inner protective member 50.

なお、外側保護部材６０は、内側保護部材５０の外周を覆うように設置された状態において、第２段部３２，３６内に収まるようになっている。すなわち、外側保護部材６０の外周面が、板状部材１０の外周部１０ａの外周面、およびベース部材２０の外周面からはみ出すことはない。これにより、静電チャック１にフォーカスリングを装着する際、外側保護部材６０がフォーカスリングに干渉しないようになっている。なお、フォーカスリングは、半導体ウエハＷの周辺部におけるプラズマの密度を半導体ウエハＷの中央部におけるプラズマの密度と同程度に維持するために使用される環状の部材である。 The outer protective member 60 is arranged to fit within the second step portions 32, 36 when it is installed to cover the outer periphery of the inner protective member 50. That is, the outer peripheral surface of the outer protective member 60 does not extend beyond the outer peripheral surface of the outer peripheral portion 10a of the plate-shaped member 10 and the outer peripheral surface of the base member 20. This prevents the outer protective member 60 from interfering with the focus ring when the focus ring is attached to the electrostatic chuck 1. The focus ring is an annular member used to maintain the plasma density at the periphery of the semiconductor wafer W at the same level as the plasma density at the center of the semiconductor wafer W.

上記のような静電チャック１を、半導体製造装置の真空チャンバー内で半導体ウエハＷを固定するために使用する場合、半導体ウエハＷに回路パターンを形成する際に使用するプラズマやプロセスガスが接合層４０に接触すると、接合層４０が腐食してしまう。そのため、本実施形態の静電チャック１では、内側保護部材５０と外側保護部材６０を設けて、接合層４０の外周面４０ａにプラズマやプロセスガスが接触することを防止している。 When the electrostatic chuck 1 as described above is used to fix a semiconductor wafer W in a vacuum chamber of a semiconductor manufacturing device, if the plasma or process gas used to form a circuit pattern on the semiconductor wafer W comes into contact with the bonding layer 40, the bonding layer 40 will corrode. Therefore, in the electrostatic chuck 1 of this embodiment, an inner protective member 50 and an outer protective member 60 are provided to prevent the plasma or process gas from coming into contact with the outer peripheral surface 40a of the bonding layer 40.

そして、本実施形態では、内側保護部材５０よりもＺ軸方向の寸法が大きい外側保護部材６０を、内側保護部材５０を覆うように第２段部３２，３６に配置している。そのため、第１段部３１，３５に配置した内側保護部材５０にねじれや傾きが発生したとしても、内側保護部材５０の外周面全域を外側から外側保護部材６０が覆うため、内側保護部材５０のねじれや傾きが修正される。すなわち、第１段部３１，３５に配置される内側保護部材５０に、ねじれや傾きが発生することを防止することができる。これにより、内側保護部材５０で接合層４０の外周面４０ａ全域を確実に覆うことができる。 In this embodiment, the outer protective member 60, which has a larger dimension in the Z-axis direction than the inner protective member 50, is placed in the second step 32, 36 so as to cover the inner protective member 50. Therefore, even if the inner protective member 50 placed in the first step 31, 35 is twisted or tilted, the outer protective member 60 covers the entire outer peripheral surface of the inner protective member 50 from the outside, so that the twist or tilt of the inner protective member 50 is corrected. In other words, it is possible to prevent the inner protective member 50 placed in the first step 31, 35 from being twisted or tilted. This ensures that the inner protective member 50 covers the entire outer peripheral surface 40a of the bonding layer 40.

従って、内側保護部材５０と外側保護部材６０とにより、接合層４０の外周面４０ａ付近にプラズマやプロセスガスが侵入することを防止することができる。なお、内側保護部材５０のねじれや傾きが完全に修正されずに、内側保護部材５０が第１段部３１，３５にずれて配置されたとしても、外側保護部材６０が内側保護部材５０を覆っているため、外側保護部材６０により、接合層４０の外周面４０ａ付近へのプラズマやプロセスガスの侵入を防止することができる。 Therefore, the inner protective member 50 and the outer protective member 60 can prevent the intrusion of plasma and process gas near the outer peripheral surface 40a of the bonding layer 40. Even if the twist or inclination of the inner protective member 50 is not completely corrected and the inner protective member 50 is positioned offset toward the first step portions 31 and 35, the outer protective member 60 covers the inner protective member 50, so the outer protective member 60 can prevent the intrusion of plasma and process gas near the outer peripheral surface 40a of the bonding layer 40.

そして、本実施形態の静電チャック１では、板状部材１０の下面１２側における外周部、およびベース部材２０の上面２１側における外周部に、内側保護部材５０を配置するための第１段部３１，３５と、外側保護部材６０を配置するための第２段部３２，３６とを設けている。そのため、内側保護部材５０および外側保護部材６０のそれぞれを位置ズレすることなく、適正な位置に配置することができる。 In the electrostatic chuck 1 of this embodiment, the outer periphery on the lower surface 12 side of the plate-like member 10 and the outer periphery on the upper surface 21 side of the base member 20 are provided with first steps 31, 35 for arranging the inner protective member 50 and second steps 32, 36 for arranging the outer protective member 60. Therefore, the inner protective member 50 and the outer protective member 60 can be arranged in the appropriate positions without being misaligned.

すなわち、内側保護部材５０の両端部を、第１段部３１の側面３１ａと第１段部３５の側面３５ａとの両方に接触させた状態で、第１段部３１，３５に配置することができる。これにより、接合層４０の外周面４０ａ全域を、内側保護部材５０によって確実に覆うことができるため、内側保護部材５０により接合層４０を確実に封止することができる。また、本実施形態では、内側保護部材５０の両端部は、第１段部３１の底面３１ｂと第１段部３５の底面３５ｂとの両方にも接触している。そのため、内側保護部材５０による接合層４０の封止性能が高められている。さらに、外側保護部材６０の両端部を、第２段部３２の側面３２ａと第２段部３６の側面３６ａとの両方に接触させた状態で、第２段部３２，３６に配置することができる。これにより、接合層４０の外周面４０ａ全域を完全に覆った状態の内側保護部材５０の全体を、外側保護部材６０によって確実に覆うことができる。そのため、外側保護部材６０によっても、接合層４０を封止することができる。このようにして、本実施形態では、内側保護部材５０と外側保護部材６０との両方で、接合層４０を封止することができるため、接合層４０の外周面４０ａ付近へのプラズマやプロセスガスの侵入を確実に防止することができる。 That is, the inner protective member 50 can be disposed in the first step 31, 35 with both ends in contact with both the side 31a of the first step 31 and the side 35a of the first step 35. This allows the entire outer peripheral surface 40a of the bonding layer 40 to be reliably covered by the inner protective member 50, so that the bonding layer 40 can be reliably sealed by the inner protective member 50. In addition, in this embodiment, both ends of the inner protective member 50 are in contact with both the bottom surface 31b of the first step 31 and the bottom surface 35b of the first step 35. Therefore, the sealing performance of the bonding layer 40 by the inner protective member 50 is improved. Furthermore, both ends of the outer protective member 60 can be disposed in the second step 32, 36 with both ends in contact with both the side surface 32a of the second step 32 and the side surface 36a of the second step 36. This allows the entire inner protective member 50, which completely covers the entire outer peripheral surface 40a of the bonding layer 40, to be reliably covered by the outer protective member 60. Therefore, the bonding layer 40 can also be sealed by the outer protective member 60. In this way, in this embodiment, the bonding layer 40 can be sealed by both the inner protective member 50 and the outer protective member 60, so that it is possible to reliably prevent the intrusion of plasma or process gas into the vicinity of the outer peripheral surface 40a of the bonding layer 40.

また、外側保護部材６０が内側保護部材５０よりも伸縮性が高いものであるため、外側保護部材６０によって内側保護部材５０を内側へより効果的に押圧することができる。そのため、第１段部３１，３５に配置された内側保護部材５０が、部分的にねじれたり、傾いたりすることを確実に防止することができる。従って、内側保護部材５０による接合層４０の封止性能をさらに高めることができる。これにより、接合層４０の外周面４０ａ付近へのプラズマやプロセスガスの侵入をより効果的に防止することができる。 In addition, because the outer protective member 60 has higher elasticity than the inner protective member 50, the outer protective member 60 can press the inner protective member 50 inward more effectively. This can reliably prevent the inner protective member 50 arranged in the first step portions 31, 35 from being partially twisted or tilted. This can further improve the sealing performance of the bonding layer 40 by the inner protective member 50. This can more effectively prevent the intrusion of plasma and process gas into the vicinity of the outer peripheral surface 40a of the bonding layer 40.

ここで、変形例について図４を参照しながら説明する。変形例では、図４に示すように、基本的な構成は上記の実施形態と同じであり、内側保護部材１５０の形状が上記の実施形態とは異なる。すなわち、変形例では、内側保護部材１５０の外周面１５０ａが、径方向（Ｘ軸又はＹ軸方向）における外側方向へ凸となる円弧形状に形成されている。 Here, a modified example will be described with reference to FIG. 4. As shown in FIG. 4, the basic configuration of the modified example is the same as that of the above embodiment, but the shape of the inner protective member 150 is different from that of the above embodiment. That is, in the modified example, the outer peripheral surface 150a of the inner protective member 150 is formed in an arc shape that is convex outward in the radial direction (X-axis or Y-axis direction).

このような変形例では、上記の実施形態と同様に、接合層４０の外周面４０ａ全域を覆うように内側保護部材１５０が第１段部３１，３５に配置され、その内側保護部材１５０の外周面１５０ａ全域を覆うように外側保護部材６０が第２段部３２，３６に配置されている。そして、変形例では、内側保護部材１５０の外周面１５０ａが外側へ凸となる円弧形状であるため、外側保護部材６０によって内側保護部材１５０を内側へより一層効果的に押圧することができる。従って、内側保護部材１５０による接合層４０の封止性能をさらに高めることができるので、接合層４０の外周面４０ａ付近へのプラズマやプロセスガスの侵入をより一層効果的に防止することができる。 In this modified example, as in the above embodiment, the inner protective member 150 is disposed on the first step 31, 35 so as to cover the entire outer peripheral surface 40a of the bonding layer 40, and the outer protective member 60 is disposed on the second step 32, 36 so as to cover the entire outer peripheral surface 150a of the inner protective member 150. In the modified example, the outer peripheral surface 150a of the inner protective member 150 has an arc shape that is convex outward, so that the outer protective member 60 can press the inner protective member 150 inward more effectively. Therefore, the sealing performance of the bonding layer 40 by the inner protective member 150 can be further improved, and the intrusion of plasma and process gas near the outer peripheral surface 40a of the bonding layer 40 can be more effectively prevented.

以上のように、本実施形態の静電チャック１によれば、内側保護部材５０により接合層４０の外周面４０ａを覆うように配置し、その内側保護部材５０を覆うように、内側保護部材５０よりもＺ軸方向の寸法が大きい外側保護部材６０を配置している。そのため、内側保護部材５０にねじれや傾きが発生することを防止することができるので、内側保護部材５０で接合層４０の外周面４０ａ全域を確実に覆うことができる。従って、内側保護部材５０と外側保護部材６０とにより、接合層４０の外周面４０ａ付近にプラズマやプロセスガスが侵入することを防止することができる。 As described above, according to the electrostatic chuck 1 of this embodiment, the inner protective member 50 is arranged to cover the outer peripheral surface 40a of the bonding layer 40, and the outer protective member 60, which has a dimension in the Z-axis direction larger than that of the inner protective member 50, is arranged to cover the inner protective member 50. This makes it possible to prevent the inner protective member 50 from twisting or tilting, and therefore the inner protective member 50 can reliably cover the entire outer peripheral surface 40a of the bonding layer 40. Therefore, the inner protective member 50 and the outer protective member 60 can prevent plasma and process gas from entering the vicinity of the outer peripheral surface 40a of the bonding layer 40.

そして、板状部材１０とベース部材２０とにそれぞれ設けた第１段部３１，３５に内側保護部材５０を配置し、第２段部３２，３６に外側保護部材６０を配置しているため、内側保護部材５０と外側保護部材６０のそれぞれを位置ズレすることなく、適正な位置に配置することができる。従って、接合層４０の外周面４０ａ全域を確実に覆った状態の内側保護部材５０の全体を外側保護部材６０で確実に覆うことができるため、内側保護部材５０によって接合層４０を確実に封止することができ、接合層４０へのプラズマやプロセスガスの侵入を防止することができる。 The inner protective member 50 is disposed on the first step 31, 35 provided on the plate-like member 10 and the base member 20, respectively, and the outer protective member 60 is disposed on the second step 32, 36, so that the inner protective member 50 and the outer protective member 60 can be disposed in the appropriate position without misalignment. Therefore, the entire inner protective member 50, which reliably covers the entire outer peripheral surface 40a of the bonding layer 40, can be reliably covered by the outer protective member 60, so that the bonding layer 40 can be reliably sealed by the inner protective member 50, and intrusion of plasma and process gas into the bonding layer 40 can be prevented.

なお、上記の実施形態は単なる例示にすぎず、本開示を何ら限定するものではなく、その要旨を逸脱しない範囲内で種々の改良、変形が可能であることはもちろんである。例えば、上記の実施形態では、本開示を静電チャックに適用した場合を例示したが、本開示は、静電チャックに限られることなく、表面に対象物を保持する保持装置全般について適用することができる。 The above embodiments are merely examples and do not limit the present disclosure in any way. Needless to say, various improvements and modifications are possible without departing from the spirit of the present disclosure. For example, the above embodiments illustrate the application of the present disclosure to an electrostatic chuck, but the present disclosure is not limited to electrostatic chucks and can be applied to any holding device that holds an object on its surface.

１静電チャック
１０板状部材
１１保持面
１２下面
２０ベース部材
２１上面
２２下面
３１第１段部
３２第２段部
３５第１段部
３６第２段部
４０接合層
５０内側保護部材
６０外側保護部材
１５０内側保護部材
１５０ａ外周面
Ｗ半導体ウエハ Reference Signs List 1: Electrostatic chuck 10: Plate-like member 11: Holding surface 12: Lower surface 20: Base member 21: Upper surface 22: Lower surface 31: First step portion 32: Second step portion 35: First step portion 36: Second step portion 40: Bonding layer 50: Inner protective member 60: Outer protective member 150: Inner protective member 150a: Outer peripheral surface W: Semiconductor wafer

Claims

A first member including a first surface and a second surface provided on an opposite side to the first surface in a first direction;
a second member including a third surface and a fourth surface provided on an opposite side of the third surface in the first direction;
a bonding layer disposed between the second surface of the first member and the third surface of the second member, bonding the first member and the second member;
A holding device for holding an object on the first surface of the first member,
An inner protective member arranged to cover the entire outer circumferential surface of the bonding layer;
an outer protective member disposed outside the inner protective member and having a dimension in the first direction larger than that of the inner protective member;
The outer protective member is disposed so as to cover the entire outer peripheral surface of the inner protective member ,
a first step for disposing the inner protective member and a second step for disposing the outer protective member are formed on an outer periphery of the first member on the second surface side and an outer periphery of the second member on the third surface side,
the inner protective member is in contact with both a side surface of the first step portion of the first member and a side surface of the first step portion of the second member,
The outer protective member is in contact with at least one of a side surface of the second step portion of the first member and a side surface of the second step portion of the second member.
A holding device characterized in that

2. The holding device according to claim 1 ,
A retaining device, wherein the outer protective member is more elastic than the inner protective member.

The holding device according to claim 1 or 2 ,
A holding device, characterized in that the outer protective member presses the inner protective member inwardly in a second direction perpendicular to the first direction.

The holding device according to claim 1 or 2 ,
A holding device, characterized in that an outer peripheral surface of the inner protective member is formed into an arc shape that is convex outward in a second direction perpendicular to the first direction.

In any one of the holding devices according to claims 1 to 4,
the outer protective member is disposed between a bottom surface of the second step portion of the first member and a bottom surface of the second step portion of the second member,
A gap exists between the outer protective member and the bottom surface of the second step portion of the first member, and a gap exists between the outer protective member and the bottom surface of the second step portion of the second member.
A holding device characterized in that

In any one of the holding devices according to claims 1 to 5,
A holding device, wherein the outer protective member has a smaller coefficient of thermal expansion than the inner protective member.