JP2004322218A

JP2004322218A - Vacuum suction device

Info

Publication number: JP2004322218A
Application number: JP2003115859A
Authority: JP
Inventors: Atsunobu Une; 篤暢宇根
Original assignee: Japan Steel Works Ltd; Technical Research and Development Institute of Japan Defence Agency
Current assignee: Japan Steel Works Ltd; Technical Research and Development Institute of Japan Defence Agency
Priority date: 2003-04-21
Filing date: 2003-04-21
Publication date: 2004-11-18
Anticipated expiration: 2023-04-21
Also published as: JP3769618B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vacuum suction unit having a vacuum suction part composed of a large number of microscopic extremely low projections, hardly causing breaking of the projections for correcting a sample into high flatness without being influenced by dust by surely sucking the sample even with support only by the projections. <P>SOLUTION: This vacuum suction device has the vacuum suction unit 14 internally provided with an evacuation hole 3 connected to a vacuum pump for supporting the sample 10 only by a large number of projections 2 having an upper surface existing on the same plane. A vacuum suction part 1 communicating with the evacuation hole 3 is made of a porous material. A large number of projections 2 composed of the porous material having a small pore diameter denser than the vacuum suction part 1, are fixedly arranged on an upper surface. Microscopic clearance 12 is formed between the vacuum suction part 1 and the sample 10 by setting the height of these projections 2 to the extremely low height of about several micrometers. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術】
本発明は、ＬＳＩ製造装置における、パターン転写装置、描画装置、各種プロセス製造装置、検査測長装置、および研削、研磨、切断などの加工装置の試料保持装置と試料搬送装置に用いられる真空吸着装置に関し、特にその真空吸着器に関するものである。
【０００２】
【従来の技術】
従来、加工に用いられている一般的な真空吸着装置は、図３（ａ），（ｂ）に示すようなポーラス型真空吸着器１４を備えている。装置は、数１０〜４０％の気孔率を有する多孔質セラミックスからなる真空吸着部１と、その外側に配設された平面状のランド部１１をもつ緻密なセラミックスからなる基部５と、真空排気を行う真空排気孔３と、真空吸着部１の下面に設けられ、中心から放射状に延びた真空排気溝４、および外周側に環状に配置された真空排気溝４’から構成される。前記真空排気溝４、４’は真空排気孔３に接続され、さらにその先は真空ポンプ（図示せず）に連結される。真空吸着部１とランド部１１は、同一平面上に高精度に仕上げ加工されている。
【０００３】
この真空吸着装置の上面に、シリコンウエハなどの試料１０を載置した後、真空ポンプを作動させると、真空排気溝４、４’を通って、真空排気孔３から矢印で示すように空気が排出され、真空吸着部１と試料１０の間は真空となり、大気圧によって試料１０は真空吸着部１上に押さえつけられる。したがって、試料１０は真空吸着部１の高精度な平面に倣い、試料の反りや曲がりが矯正される。
【０００４】
一方、ＬＳＩ製造において用いられる、下記特許文献１又は２に記載の真空吸着装置は、図４（ａ），（ｂ）又は図５（ａ），（ｂ）に示すような真空吸着器１４を備えている。
【０００５】
この従来の真空吸着器１４の上面には、多数の微小な突起２を一体に有する前述した多孔質セラミックスからなる真空吸着部１と、環状の突部によって形成され真空吸着部１を取り囲むランド部１１が設けられている。また、上記真空吸着部１の下面には中心から放射状に延びる真空排気溝４と、外周側に環状に配置された真空排気溝４’が設けられ、中心部で真空排気孔３に接続される。
【０００６】
このような真空吸着器１４において、真空吸着器１４の上面にシリコンウエハ等の試料１０を載置した後、真空ポンプ（図示せず）を作動させて試料１０の下部の空気を真空排気孔３から排気すると、真空吸着部１が負圧となり、突起２の間の微小隙間１２は真空となるので、試料１０は突起２およびランド部１１上に吸着される。ランド部１１の上面は突起２の上面と同一平面を形成し、試料１０の裏面外周縁部が密接されることで、真空吸着部１を真空封止する。試料１０は、真空吸着されることで突起２およびランド部１１の上面に倣い、反りや曲がりが矯正される。
【０００７】
【特許文献１】
特開平１０−１２８６３３号公報
【０００８】
【特許文献２】
特公昭６２−４５６９６号公報
【０００９】
【発明が解決しようとする課題】
上記した図３（ａ），（ｂ）に示す従来のポーラス型真空吸着器１４は、上述したように数１０〜４０％の気孔率のため試料１０の裏面との接触率が大きく、したがって、真空吸着部１上にダストが付着する確率が高く、付着した場合には除去しにくく、試料の平坦度を劣化させるという欠点があった。
【００１０】
一方、上記した図４（ａ），（ｂ）又は図５（ａ），（ｂ）に示す、真空吸着部１に突起２を一体に形成した真空吸着装置の真空吸着器１４にあっては、真空排気によって試料１０を真空吸着部１の突起２とランド部１１の上面に吸着することにより、試料１０の反りや変形を矯正し平面にすることができる。また、突起２により真空吸着部１と試料１０との接触面積を極めて小さくすることができるので、ダスト等による平面度の低下はほとんど生じない。しかし、完全な真空封止を狙ってランド部１１を設けているため、このランド部１１上にダスト等が付着する可能性が高く、ポーラス型チャックと同様に試料１０の外周部を高精度な平面に矯正できないという問題があった。
【００１１】
また、図５（ａ），（ｂ）に示すように、突起２も真空吸着部１と同様の多孔質材料からなるため、その上面に形成された突起表面にも数１０μｍから数１００μｍの気孔を持つことになり、突起径より気孔径が大きい場合には突起が形成できない、あるいは形成できても欠け部が多くなり、小さな外力により折損するなどの欠点を有していた。また、突起２と外周部に設けられたランド部１１では面積分布が異なるため、加工により突起２はランド部１１と比較して低く加工され、平面度を劣化させるという問題を有していた。
【００１２】
本発明は上記した従来の問題点に鑑みてなされたもので、その目的とするところは、突起のみによる支承であるにも拘らず試料を確実に吸着し、ダスト等の影響を受けないで試料を高い平面に矯正することができ、突起全てが欠けることはなく、突起の折損なども生じにくく、微小な多数の極めて高さの低い突起からなる真空吸着部をもつ真空吸着器を提供することにある。
【００１３】
【課題を解決するための手段】
上記目的を達成するため、本発明は、図６（ａ），（ｂ）の第１の実施の形態に示すように、上面が同一平面上にある多数の突起２のみによって試料１０を支承し、内部に真空ポンプに接続される真空排気孔３を設けた真空吸着器１４を備えた真空吸着装置において、真空排気孔３に連通する真空吸着部１を、突起径の１／２以下の最大気孔径を有する多孔質セラミックス材料で作り、その上面に多数の微小突起２を設けるとともに、この突起２の高さを数μｍ程度の極めて低い高さに設定することにより前記真空吸着部１と前記試料１０との間に微小隙間１２を形成したことを特徴としている。
【００１４】
さらに、図１（ａ），（ｂ）の第２の実施の形態に示すように、上面が同一平面上にある多数の突起２のみによって試料１０を支承し、内部に真空ポンプに接続される真空排気孔３を設けた真空吸着器１４を備えた真空吸着装置において、真空排気孔３に連通する真空吸着部１を多孔質材料で作り、その上面に、真空吸着部１より緻密な材料からなる多数の微小突起２を固着して設けるとともに、この突起２の高さを数μｍ程度の極めて低い高さに設定することにより前記真空吸着部１と前記試料１０との間に微小隙間１２を形成したことを特徴としている。
【００１５】
上記真空吸着部１は、数１０〜４０％程度の気孔率を有する多孔質セラミックス材料からなる。また、上記突起２は、高さが数μｍ程度（望ましくは１μｍ〜５μｍ程度）であって、直径が数１０〜数１００μｍ程度（望ましくは１０μｍ〜２００μｍ程度）のガラス又は金属及び無機又は有機材料のような緻密な構造の他種材料により形成させることができる。又は、上記突起２は、上記と同様の形状の上記真空吸着部１と同質の多孔質セラミックス材料であって、最大気孔径が突起径の１／２以下で気孔率が数１０〜４０％程度の、上記真空吸着部１よりも気孔径が小さい多孔質セラミックス材料により形成させることができる。
【００１６】
さらに、上記目的を達成するため、本発明は、図２（ａ），（ｂ）の第３の実施の形態に示すように、上面が同一平面上にある多数の微小突起１０２ａのみによって試料１０を支承し、内部に真空ポンプ７に接続される真空排気孔３を設けた真空吸着器１４を備えた真空吸着装置において、
真空排気孔３に連通する真空吸着部１を多孔質材料で作り、その上面に、真空吸着部１より気孔径の小さい多孔質材料からなり、薄板状の基体１０２ｂの上面に多数の微小突起１０２ａが一体に形成された突起板１０２を層状に設け、この突起１０２ａの高さを数μｍ程度の極めて低い高さに設定することにより前記真空吸着部１と前記試料１０との間に微小隙間１２を形成したことを特徴としている。
【００１７】
上記真空吸着部１は、数１０〜４０％程度の気孔率を有する多孔質セラミックス材料からなり、上記突起板１０２は、上記真空吸着部１よりも気孔径の小さい組成構造を有する多孔質セラミックス材料、すなわち突起径の１／２以下の最大気孔径で数１０〜４０％程度の気孔率を有する多孔質セラミックス材料からなることを特徴としている。
【００１８】
さらに、本発明は、図７（ａ），（ｂ）、図８（ａ），（ｂ）の第４、５の実施の形態に示すように、上面が同一平面上にある多数の微小突起２のみによって試料１０を支承し、内部に真空ポンプ７に接続される真空排気孔３を設けた真空吸着器１４を備えた真空吸着装置において、
上記真空吸着部１の中心付近に、真空吸着部１に吸着する試料１０を持ち上げるリフト機構を通す穴１５、もしくは周辺部に切り欠き１６を設けたことを特徴としている。
【００１９】
【作用】
上記本発明においては、最大気孔径が突起径の１／２以下の多孔質セラミックス材料からなる真空吸着部１上に、突起２を設けることによって、もしくは多孔質材料からなる真空吸着部１上に、同種もしくは異種の、真空吸着部１より緻密な若しくは気孔径の小さい多孔質材料からなる突起２（１０２ａ）を固着して設けることによって、試料１０裏面との接触面積を極めて小さくし、ダストの影響を少なくすることが可能となるので、試料１０全面を容易に高精度の平面に矯正することができる。
【００２０】
また、薄い試料を真空吸着するためには、突起ピッチが小さく、一定間隔であることが必要であるが、上記従来のように突起径より大きい気孔を有する多孔質材料上に一体に形成された突起では、気孔部の突起が全体もしくは１／２以上欠けることもあり、一定間隔で試料を支持することができなくなるため平面度が劣化する。本発明では、最大気孔径が突起径の１／２以下の多孔質セラミックス材料からなる真空吸着部１上に突起を形成する、もしくは真空吸着部１より緻密な若しくは気孔径の小さい多孔質材料からなる突起２（１０２ａ）を、真空吸着部１の多孔質材料上に固着させるようにして形成するので、気孔部にも突起２（１０２ａ）を形成することが可能になり、一定間隔の高さの揃った突起を形成することができる。
【００２１】
さらに、突起の材料も選択できるので、サンドブラスト加工に替えて、リソグラフィ技術を利用して、例えば数１０μｍ径以下の突起を高さ数μｍ以下にするなど極めて小さく且つ低く形成することも可能になる。したがって、突起の間隔を小さくしてもウエハとの接触面積を増大することなく、且つ試料１０と真空吸着部１との間の微小隙間を極めて小さくでき、真空リークを抑制することも可能になるので、真空をシールするランド部が不要となる。
【００２２】
また、図７や図８に示したように、ウエハを持ち上げるためのリフト機構を通す穴１５や切り欠き１６を、これらを取り囲む真空をシールするランド部を形成することなく造り上げることができるので、この製造工程を省くことができ、製品を安価に製造できる特長をもつ。このため試料１０を支承する部分を突起のみとすることができ、突起表面加工時に、工具との接触面積分布がどの部分でも等しくなるので、吸着部全面における平面度を向上することが容易になる。
【００２３】
【発明の実施の形態】
図６（ａ），（ｂ）は、本発明に係わる真空吸着装置の第１の実施の形態を示す平面図と正断面図である。
図に示すように、緻密なセラミックスからなる装置の基部５の上部に、数１０〜４０％の気孔率を有し、最大気孔径が突起径の１／２より小さい多孔質セラミックスからなる真空吸着部１がガラス剤などにより溶着される。さらに真空吸着部１の上面に、多数の円形断面をもつピン状の微小突起２が設けられ、微小突起２は真空吸着時に試料１０にたわみを生じないように試料１０の厚さに応じたピッチにて離散配置され、かつ接触面積を減らすためにできる限り小さく造られている。
【００２４】
本実施例では、突起２は最大気孔径が突起径の１／２以下の多孔質セラミックス材料からなる真空吸着部１上に造られているので、最大気孔径が突起径より大きい多孔質材料からなる突起と比較して折損し難く、突起に一部欠けを発生することはあるが全体が欠けることはない。したがって、一定間隔で配置された突起を造ることができ、薄い厚さの試料１０を変形なく吸着することが可能になる。
【００２５】
図１（ａ），（ｂ）は、本発明に係わる真空吸着装置の第２の実施の形態を示す平面図と正断面図である。
図に示すように、緻密なセラミックスからなる装置の基部５の上部に、数１０〜４０％の気孔率を有する多孔質セラミックスからなる真空吸着部１がガラス剤などにより溶着される。さらに真空吸着部１の上面に、多数の円形断面をもつ異種もしくは同種の真空吸着部１より緻密な若しくは気孔径に小さい多孔質材料からなるピン状の微小突起２が固着して設けられ、微小突起２は真空吸着時に試料１０にたわみを生じないように試料１０の厚さに応じたピッチにて離散配置され、かつ接触面積を減らすためにできる限り小さく造られている。
【００２６】
上記突起２を真空吸着部１に固着させる方法としては、スピンコーティング法、ＣＶＤスパッタ法、ディップ法等の公知の方法により薄膜を形成後、リソグラフ技術やサンドブラスト法等により突起を製作するプロセスを用いることができる。
【００２７】
基部５の上面の真空吸着部１と接する部分には、真空排気溝４、４’が設けられている。真空排気溝４は中心から放射状に、真空排気溝４’は真空吸着部１の外周部に環状に配置され、それらは互いに連通している。真空排気溝４は真空排気孔３に連通し、真空排気孔３は真空ポンプ７に連結されている。
【００２８】
上記真空吸着器１４においては、真空排気孔３から空気を排出することにより、矢印のように空気が流れ、試料１０と真空吸着部１間の微小隙間１２の空気が排出される。突起２は極めて低く造られているので、ランド部が無くても試料外周から空気の流入は抑制され、微小隙間１２の圧力が下がり、試料１０は大気圧により微小突起２の上面に押さえつけられ、試料１０が平面に矯正される。
【００２９】
このような真空吸着装置においては、多孔質セラミックスからなる真空吸着部１の上面に、微小突起２を固着して設けているので、微小突起２の上面と試料１０の裏面との接触面積は極めて小さく、微小突起２の上面と試料１０の裏面との接触率を、従来のポーラス型真空吸着器に比較し１０分の１以下に減少させることができる。
【００３０】
したがって、ゴミの影響を少なくすることが可能となり、試料１０の全面を容易に高精度の平面に矯正することができる。また、微小突起２の間に存在する空気は真空吸着部１の多孔質材料の気孔を通って真空排気溝４、４’に流れ込むので、微小突起２の高さを大きくしなくても真空度分布を均一にすることができる。前記突起２の高さはゴミを落とすことができる高さで十分であり、１μｍから５μｍ程度、すなわちピン径に対し２０分の１以下と小さくすることができる。したがって、微小突起２の高さは断面の直径に比べて数１０分から１００分の一近くまで小さく形成することができるので、微小突起２は破損しにくく、かつ微小突起２の間の溝が浅いので、ゴミなどが付着したとしても容易に洗浄除去することができる。
【００３１】
また、微小突起２の高さを小さくすれば微小突起２の直径をさらに小さくすることができるので、試料１０の裏面と微小突起２の上面との接触率を一層小さくすることができ、ゴミの影響を極限まで抑制することができる。さらに、微小突起２のピッチを小さくすることによって薄い試料１０を変形させることなく真空吸着することも可能になる。
【００３２】
突起２は、真空吸着部１より緻密な異種もしくは同種の材料で造られているので、多孔質材料からなる突起と比較して折損し難く、また、真空吸着部１上に気孔があった場合にも突起を造ることが可能になり、多孔質材料からなる真空吸着部１の上面に一定間隔で配置された突起を造ることができる。
【００３３】
真空排気孔３には、接続ホース６を介して真空ポンプ７および清浄空気を供給することができる清浄空気供給装置８に連結され、接続ホース６に切替弁９が設けられている。
【００３４】
上記真空吸着装置においては、試料１０すなわち半導体ウェハを真空吸着部１に載置し、切替弁９を切り替えて真空ポンプ８と真空排気孔３とを導通すると、真空排気溝４、４’を通って真空排気孔３から矢印で示すように空気が排出され、突起２と試料１０の裏面間にある空気は多孔質の穴を通って排出される。このことによって、試料１０と真空吸着部１との間の圧力が下がり、試料１０は大気圧により微小突起２の上面に押さえつけられ、試料１０が平面に矯正される。つぎに、切替弁９を切り替えて真空ポンプ７と真空排気孔３との導通を切り、清浄空気供給装置８と真空排気孔３とを導通し、真空排気孔３に清浄空気を送ると、清浄空気が真空吸着部１の上面から吹き出すから、試料１０は空気圧により容易に離脱する。そして、次の試料１０が載置されるまで、清浄空気を流し続ける。この状態で、試料１０が真空吸着部１の上面に載置されたとき、切替弁９を切り替えて真空ポンプ７と真空排気孔３とを導通すると、試料１０は真空吸着される。
【００３５】
なお、上述実施の形態においては、突起としてピン状の微小突起２を設けたが、突起として特開平７−３０２８３２号公報の図３に示されるような多数の同心円上に配置された環状突起を設けてもよい。また、上述実施の形態においては、断面が円形の微小突起２を設けたが、断面が矩形等の微小突起を設けてもよい。また、上述実施の形態においては、円形の真空吸着部１を設けたが、矩形、楕円等の真空吸着部を設けてもよい。また、上述実施の形態においては、多孔質材料からなる真空吸着部として多孔質セラミックスからなる真空吸着部１を用いたが、多孔質からなる真空吸着部として他の多孔質材料からなる真空吸着部を用いてもよい。
【００３６】
図２（ａ），（ｂ）は、本発明に係わる真空吸着装置の第３の実施の形態を示す平面図と正断面図である。
第３の実施の形態では、上記と同様の真空吸着部１の上面に、真空吸着部１より気孔径の小さい多孔質材料からなり、薄板状の基体１０２ｂの上面に多数の微小突起１０２ａが一体に形成された突起板１０２を層状に設けている。真空吸着部１と突起板１０２とは、ガラス剤による部分溶着、あるいは嵌合などにより固定されている。もしくは、泥奨鋳込法などによって成形されている。
【００３７】
上記突起板１０２は、上記真空吸着部１よりも気孔径の小さい組成構造を有する多孔質セラミックス材料、すなわち突起径の１／２以下の最大気孔径で数１０〜４０％程度の気孔率を有する多孔質セラミックス材料により形成されている。また、突起１０２ａの高さは、１μｍから５μｍ程度の極めて低い高さに設定されている。また、基体１０２ｂの高さは、空気の流量抵抗を抑制するために数１００μｍ〜数ｍｍ以下とされている。
【００３８】
上記第３の実施の形態の説明において、上記第１の実施の形態と対応する箇所の図面には、同一の符号を付して、その詳細な説明は省略した。
【００３９】
図７（ａ），（ｂ）は、本発明に係わる真空吸着装置の第４の実施の形態を示す平面図とＡＯＡ’断面図である。
第４の実施の形態では、上記真空吸着部１の中心部に試料１０を持ち上げるリフト機構を通す穴１５が３個設けられている。この穴１５を通して試料１０は上部に持ち上げられ、側面から挿入された受け渡し用の搬送アームにより試料１０は搬出される。従来のセラミックス製の真空ピンチャックでは突起の高さが数１００μｍと大きかったため、この穴１０の周りに真空をシールするランド部を設けて真空漏れを防いでいたが、本発明では穴１０の側内面１７（ＡＯＡ’ 断面に太線で示す）部をガラス剤や高分子樹脂などにより封止するだけでよく、ランド部を新たに設ける必要はない。
【００４０】
図８（ａ），（ｂ）は、本発明に係わる真空吸着装置の第５の実施の形態を示す平面図とＡＯＡ’断面図である。
第５の実施の形態では、上記真空吸着部１の周辺に試料１０を持ち上げるリフト機構を通す切り欠き１６が３カ所設けられている。この切り欠き１６に下方から上方に向かってリフト機構が上昇して、試料１０は上に持ち上げられ、側面から挿入された受け渡し用の搬送アームにより搬出される。従来のセラミックス製の真空ピンチャックでは突起の高さが数１００μｍと大きかったため、この切り欠き１６の周りに真空をシールするランド部を設けて真空漏れを防いでいたが、本発明では切り欠き１６の側内面１８（ＡＯＡ’ 断面に斜めのハッチングで示す）部をガラス剤や高分子樹脂などにより封止するだけでよく、ランド部を新たに設ける必要はない。
【００４１】
【発明の効果】
本発明に係わる真空吸着装置においては、突起の上面と試料の裏面との接触面積が極めて小さいので、ゴミの影響を少なくすることが可能となり、試料全面を容易に高精度の平面に矯正することができる。また、突起の高さを極めて低く、かつ多孔質材料の気孔部上にも形成できるので、突起の強さを数倍も向上でき、耐久性を上げることができると同時に、極めてピッチの小さい一定間隔で並んだ突起の形成により２００μｍより薄い試料を変形することなく吸着することも可能になる。
【図面の簡単な説明】
【図１】（ａ），（ｂ）は本発明の第２の実施の形態に係る真空吸着装置を構成する真空吸着器の一実施例を示す平面図および正断面図である。
【図２】（ａ），（ｂ）は本発明の第３の実施の形態に係る真空吸着装置を構成する真空吸着器の一実施例を示す平面図および正断面図である。
【図３】（ａ），（ｂ）は従来のポーラス型真空吸着器の正面図および正断面図である。
【図４】（ａ），（ｂ）は従来の多孔質突起をもつポーラス型真空吸着器の正面図および正断面図である。
【図５】（ａ），（ｂ）は従来の多孔質突起をもつポーラス型真空吸着器の拡大正面図および拡大正断面図である。
【図６】（ａ），（ｂ）は本発明の第１の実施の形態に係る真空吸着装置を構成する真空吸着器の一実施例を示す平面図および正断面図である。
【図７】（ａ），（ｂ）は本発明の第４の実施の形態に係る真空吸着装置を構成する真空吸着器の一実施例を示す平面図およびＡＯＡ’断面図である。
【図８】（ａ），（ｂ）は本発明の第５の実施の形態に係る真空吸着装置を構成する真空吸着器の一実施例を示す平面図およびＡＯＡ’断面図である。
【符号の説明】
１…真空吸着部、２…突起、３…真空排気孔、４，４’…真空排気溝、５…基部、６…接続ホース、７…真空ポンプ、８…清浄空気供給装置、９…切替弁、１０…試料、１１…ランド部、１２…微小隙間、１４…真空吸着器、１５…リフト機構を通す穴、１６…リフト機構を通す切り欠き、１７…リフト機構を通す穴側面、１８…リフト機構を通す切り欠き側面、１０２…突起板、１０２ａ…突起、１０２ｂ…基体。[0001]
[Technology to which the invention belongs]
The present invention relates to a pattern transfer device, a drawing device, various process manufacturing devices, an inspection and length measuring device, and a sample holding device and a vacuum suction device used for a sample transfer device of a processing device such as grinding, polishing, and cutting in an LSI manufacturing device. And more particularly, to the vacuum adsorber.
[0002]
[Prior art]
Conventionally, a general vacuum suction device used for processing includes a porous vacuum suction device 14 as shown in FIGS. 3 (a) and 3 (b). The apparatus comprises a vacuum suction portion 1 made of porous ceramics having a porosity of several tens to 40%, a base 5 made of dense ceramics having a flat land portion 11 disposed outside thereof, and a vacuum evacuation. , A vacuum exhaust groove 4 provided on the lower surface of the vacuum suction unit 1 and extending radially from the center, and a vacuum exhaust groove 4 ′ annularly arranged on the outer peripheral side. The evacuation grooves 4, 4 'are connected to the evacuation holes 3, and further connected to a vacuum pump (not shown). The vacuum suction part 1 and the land part 11 are finished with high precision on the same plane.
[0003]
After the sample 10 such as a silicon wafer is placed on the upper surface of the vacuum suction device, when the vacuum pump is operated, air passes through the vacuum evacuation grooves 4 and 4 ′ and evacuation from the vacuum evacuation hole 3 as shown by arrows. Then, the space between the vacuum suction unit 1 and the sample 10 is evacuated, and the sample 10 is pressed onto the vacuum suction unit 1 by the atmospheric pressure. Therefore, the sample 10 follows the highly accurate flat surface of the vacuum suction unit 1, and the sample is corrected for warpage and bending.
[0004]
On the other hand, a vacuum suction device described in Patent Literature 1 or 2 used in LSI manufacturing includes a vacuum suction device 14 as shown in FIGS. 4 (a) and (b) or FIGS. 5 (a) and 5 (b). Have.
[0005]
On the upper surface of the conventional vacuum adsorber 14, a vacuum adsorbing portion 1 made of the above-described porous ceramics having a large number of minute projections 2 integrally, and a land portion formed by an annular protrusion and surrounding the vacuum adsorbing portion 1 are provided. 11 are provided. In addition, a vacuum exhaust groove 4 extending radially from the center and a vacuum exhaust groove 4 ′ arranged annularly on the outer peripheral side are provided on the lower surface of the vacuum suction unit 1, and are connected to the vacuum exhaust holes 3 at the center. .
[0006]
In such a vacuum suction device 14, after a sample 10 such as a silicon wafer is placed on the upper surface of the vacuum suction device 14, a vacuum pump (not shown) is operated to evacuate the air below the sample 10 to the vacuum exhaust holes 3. When the sample is evacuated, the vacuum suction unit 1 becomes negative pressure and the minute gap 12 between the projections 2 becomes vacuum, so that the sample 10 is sucked onto the projection 2 and the land 11. The upper surface of the land portion 11 forms the same plane as the upper surface of the projection 2, and the outer peripheral edge of the back surface of the sample 10 is tightly closed, so that the vacuum suction portion 1 is vacuum-sealed. The sample 10 follows the protrusions 2 and the upper surface of the land portion 11 by being vacuum-adsorbed, and corrects warpage and bending.
[0007]
[Patent Document 1]
JP-A-10-128633
[Patent Document 2]
Japanese Patent Publication No. Sho 62-45696
[Problems to be solved by the invention]
As described above, the conventional porous vacuum suction device 14 shown in FIGS. 3A and 3B has a high porosity of several tens to 40%, so that the contact ratio with the back surface of the sample 10 is large. There is a drawback that dust has a high probability of adhering to the vacuum suction unit 1 and is difficult to remove when adhering, thereby deteriorating the flatness of the sample.
[0010]
On the other hand, in the vacuum suction device 14 of the vacuum suction device in which the projections 2 are formed integrally with the vacuum suction portion 1 shown in FIGS. 4 (a) and 4 (b) or FIGS. 5 (a) and 5 (b). By adsorbing the sample 10 on the projection 2 of the vacuum suction unit 1 and the upper surface of the land 11 by vacuum evacuation, it is possible to correct the warpage and deformation of the sample 10 to make it flat. Further, since the contact area between the vacuum suction unit 1 and the sample 10 can be made extremely small by the projections 2, the flatness is hardly reduced by dust or the like. However, since the land portion 11 is provided for complete vacuum sealing, there is a high possibility that dust or the like adheres to the land portion 11, and the outer peripheral portion of the sample 10 can be formed with high precision similarly to the porous chuck. There was a problem that it could not be straightened.
[0011]
Further, as shown in FIGS. 5 (a) and 5 (b), the protrusion 2 is also made of the same porous material as the vacuum suction part 1, so that the surface of the protrusion formed on the upper surface thereof has pores of several tens μm to several hundreds μm. When the pore diameter is larger than the diameter of the projection, the projection cannot be formed, or even if it can be formed, the number of notches increases, and the projection is broken by a small external force. In addition, since the area distribution is different between the protrusion 2 and the land portion 11 provided on the outer peripheral portion, the protrusion 2 is processed to be lower than the land portion 11 by processing, and there is a problem that the flatness is deteriorated.
[0012]
The present invention has been made in view of the above-described conventional problems, and aims at reliably adsorbing a sample despite being supported only by protrusions and preventing the sample from being affected by dust and the like. To provide a vacuum suction device having a vacuum suction portion composed of a large number of extremely low protrusions, which can correct the surface to a high plane, does not chip all the protrusions, hardly causes breakage of the protrusions, etc. It is in.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, as shown in the first embodiment of FIGS. 6A and 6B, the sample 10 is supported only by a large number of protrusions 2 whose upper surfaces are on the same plane. In a vacuum suction apparatus provided with a vacuum suction device 14 provided with a vacuum exhaust hole 3 connected to a vacuum pump inside, the vacuum suction unit 1 communicating with the vacuum exhaust hole 3 is set to a maximum of 1/2 or less of the protrusion diameter. It is made of a porous ceramic material having a pore diameter, provided with a large number of fine projections 2 on the upper surface thereof, and by setting the height of the projections 2 to a very low height of about several μm, the vacuum suction portion 1 and the It is characterized in that a minute gap 12 is formed between itself and the sample 10.
[0014]
Further, as shown in the second embodiment of FIGS. 1 (a) and 1 (b), the sample 10 is supported only by a large number of projections 2 whose upper surfaces are on the same plane, and is internally connected to a vacuum pump. In a vacuum suction device provided with a vacuum suction device 14 provided with a vacuum exhaust hole 3, the vacuum suction portion 1 communicating with the vacuum exhaust hole 3 is made of a porous material, and the upper surface thereof is made of a material more dense than the vacuum suction portion 1. A large number of microprojections 2 are fixedly provided, and the height of the projections 2 is set to an extremely low height of about several μm so that a minute gap 12 is formed between the vacuum suction unit 1 and the sample 10. It is characterized by being formed.
[0015]
The vacuum suction part 1 is made of a porous ceramic material having a porosity of several tens to 40%. The projection 2 has a height of about several μm (preferably about 1 μm to 5 μm) and a diameter of about several tens to several hundreds μm (preferably about 10 μm to 200 μm) of glass or metal and an inorganic or organic material. It can be formed of other materials having a dense structure as described above. Alternatively, the protrusion 2 is a porous ceramic material of the same shape as the vacuum suction portion 1 having the same shape as described above, and has a maximum pore diameter of 1/2 or less of the protrusion diameter and a porosity of several tens to 40%. However, it can be formed of a porous ceramic material having a smaller pore diameter than the vacuum suction part 1.
[0016]
Furthermore, in order to achieve the above object, as shown in the third embodiment of FIGS. 2 (a) and 2 (b), the present invention employs only a small number of microprojections 102a having an upper surface on the same plane. And a vacuum suction device provided with a vacuum suction device 14 provided with a vacuum exhaust hole 3 connected to the vacuum pump 7 therein.
The vacuum suction portion 1 communicating with the vacuum exhaust hole 3 is made of a porous material, and on the upper surface thereof is formed of a porous material having a smaller pore diameter than the vacuum suction portion 1, and a large number of fine projections 102a are formed on the upper surface of a thin plate-like base 102b. Is provided in a layer shape, and the height of the projections 102a is set to an extremely low height of about several μm so that a minute gap 12 is formed between the vacuum suction part 1 and the sample 10. Is formed.
[0017]
The vacuum suction unit 1 is made of a porous ceramic material having a porosity of about several tens to 40%, and the projection plate 102 is made of a porous ceramic material having a composition structure having a smaller pore diameter than the vacuum suction unit 1. That is, it is characterized by being made of a porous ceramic material having a maximum pore diameter of not more than 1/2 of the projection diameter and a porosity of about several tens to 40%.
[0018]
Further, as shown in the fourth and fifth embodiments of FIGS. 7A, 7B, 8A, and 8B, the present invention provides a large number of microprojections having an upper surface on the same plane. In a vacuum suction device provided with a vacuum suction device 14 which supports the sample 10 by only 2 and has a vacuum exhaust hole 3 connected to the vacuum pump 7 therein,
A hole 15 is provided near the center of the vacuum suction unit 1 for passing a lift mechanism for lifting the sample 10 to be suctioned to the vacuum suction unit 1, or a notch 16 is provided in a peripheral portion.
[0019]
[Action]
In the present invention, the protrusions 2 are provided on the vacuum suction portion 1 made of a porous ceramic material having a maximum pore diameter of 1/2 or less of the protrusion diameter, or on the vacuum suction portion 1 made of a porous material. By fixing and providing a projection 2 (102a) of the same or different kind, which is made of a porous material that is denser or smaller in pore diameter than the vacuum suction unit 1, the contact area with the back surface of the sample 10 is extremely small, Since the influence can be reduced, the entire surface of the sample 10 can be easily corrected to a highly accurate flat surface.
[0020]
Further, in order to vacuum-adsorb a thin sample, it is necessary that the pitch of the projections is small and the intervals between the projections are constant. However, they are integrally formed on a porous material having pores larger than the diameter of the projections as in the above-described conventional case. In the projections, the projections of the pores may be missing in whole or in half or more, and it becomes impossible to support the sample at regular intervals, so that the flatness is deteriorated. In the present invention, the protrusions are formed on the vacuum suction part 1 made of a porous ceramic material having a maximum pore diameter of 1/2 or less of the protrusion diameter, or a porous material having a smaller pore diameter or a smaller pore diameter than the vacuum suction part 1 is formed. The protrusion 2 (102a) is formed so as to be fixed on the porous material of the vacuum suction part 1, so that the protrusion 2 (102a) can be formed also in the pore portion, and the height of the protrusion 2 (102a) is constant. Can be formed.
[0021]
Further, since the material of the protrusion can be selected, it is possible to use a lithography technique instead of sandblasting to form a protrusion having a diameter of several tens of μm or less, for example, a height of several μm or less, and to make it extremely small and low. . Therefore, even if the interval between the protrusions is reduced, the minute gap between the sample 10 and the vacuum suction unit 1 can be extremely reduced without increasing the contact area with the wafer, and the vacuum leak can be suppressed. Therefore, a land portion for sealing a vacuum is not required.
[0022]
Further, as shown in FIGS. 7 and 8, the holes 15 and the notches 16 through which the lift mechanism for lifting the wafer is passed can be formed without forming a land portion for sealing a vacuum surrounding these holes. This manufacturing process can be omitted, and the product can be manufactured at low cost. For this reason, the portion supporting the sample 10 can be formed only by the protrusion, and the contact area distribution with the tool becomes equal at any portion during the processing of the protrusion surface, so that it is easy to improve the flatness over the entire suction portion. .
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
6 (a) and 6 (b) are a plan view and a front sectional view showing a first embodiment of the vacuum suction device according to the present invention.
As shown in the figure, a vacuum adsorption made of a porous ceramic having a porosity of several tens to 40% and a maximum pore diameter smaller than 1/2 of the protrusion diameter is provided on the base 5 of the device made of a dense ceramic. The part 1 is welded by a glass agent or the like. Further, on the upper surface of the vacuum suction unit 1, there are provided a plurality of pin-shaped fine protrusions 2 having a circular cross section, and the fine protrusions 2 have a pitch corresponding to the thickness of the sample 10 so that the sample 10 does not bend during vacuum suction. And are made as small as possible to reduce the contact area.
[0024]
In the present embodiment, the projections 2 are formed on the vacuum suction part 1 made of a porous ceramic material having a maximum pore diameter of 1/2 or less of the projection diameter. The projections are less likely to break than the projections, and the projections may be partially chipped but not entirely. Therefore, it is possible to form projections arranged at regular intervals, and it is possible to adsorb the thin sample 10 without deformation.
[0025]
FIGS. 1A and 1B are a plan view and a front sectional view showing a second embodiment of the vacuum suction device according to the present invention.
As shown in the figure, a vacuum suction unit 1 made of porous ceramics having a porosity of several tens to 40% is welded to an upper portion of a base 5 of a device made of dense ceramics by a glass agent or the like. Further, pin-shaped micro-projections 2 made of a porous material that is denser or smaller in pore diameter than the vacuum adsorption units 1 of different or similar types having a large number of circular cross sections are fixedly provided on the upper surface of the vacuum adsorption unit 1. The projections 2 are discretely arranged at a pitch corresponding to the thickness of the sample 10 so as not to bend the sample 10 during vacuum suction, and are made as small as possible to reduce the contact area.
[0026]
As a method of fixing the projections 2 to the vacuum suction unit 1, a process of forming a thin film by a known method such as a spin coating method, a CVD sputtering method, or a dip method, and then manufacturing the projections by a lithographic technique or a sandblasting method is used. be able to.
[0027]
Vacuum evacuation grooves 4 and 4 ′ are provided in a portion of the upper surface of the base 5 that contacts the vacuum suction unit 1. The evacuation grooves 4 are arranged radially from the center, and the evacuation grooves 4 ′ are annularly arranged on the outer periphery of the vacuum suction unit 1, and they are in communication with each other. The evacuation groove 4 communicates with the evacuation hole 3, and the evacuation hole 3 is connected to a vacuum pump 7.
[0028]
In the vacuum adsorber 14, air is exhausted from the vacuum exhaust holes 3 so that air flows as indicated by arrows, and air in the minute gap 12 between the sample 10 and the vacuum adsorption unit 1 is exhausted. Since the protrusion 2 is formed extremely low, even without a land portion, the inflow of air from the outer periphery of the sample is suppressed, the pressure in the minute gap 12 decreases, and the sample 10 is pressed against the upper surface of the minute protrusion 2 by the atmospheric pressure. The sample 10 is straightened.
[0029]
In such a vacuum suction device, since the fine protrusions 2 are fixedly provided on the upper surface of the vacuum suction portion 1 made of porous ceramics, the contact area between the upper surface of the fine protrusions 2 and the back surface of the sample 10 is extremely small. It is small, and the contact ratio between the upper surface of the microprojections 2 and the back surface of the sample 10 can be reduced to 1/10 or less as compared with the conventional porous vacuum suction device.
[0030]
Therefore, the influence of dust can be reduced, and the entire surface of the sample 10 can be easily corrected to a highly accurate flat surface. Further, the air existing between the minute projections 2 flows into the evacuation grooves 4, 4 'through the pores of the porous material of the vacuum suction part 1, so that the vacuum degree can be increased without increasing the height of the minute projections 2. The distribution can be made uniform. The height of the protrusion 2 is sufficient to remove dust, and can be reduced to about 1 μm to 5 μm, that is, as small as 1/20 or less of the pin diameter. Therefore, since the height of the microprojections 2 can be formed to be several tens of minutes to nearly one hundredth of the diameter of the cross section, the microprojections 2 are hardly damaged and the grooves between the microprojections 2 are shallow. Therefore, even if dust or the like adheres, it can be easily washed and removed.
[0031]
Further, if the height of the microprojections 2 is reduced, the diameter of the microprojections 2 can be further reduced, so that the contact ratio between the back surface of the sample 10 and the upper surface of the microprojections 2 can be further reduced, and The influence can be suppressed to the limit. Further, by reducing the pitch of the minute projections 2, it becomes possible to vacuum-adsorb the thin sample 10 without deforming it.
[0032]
Since the projection 2 is made of a different material or the same kind of material that is denser than the vacuum suction part 1, it is harder to break as compared with the projection made of a porous material, and when there are pores on the vacuum suction part 1. It is also possible to form projections at regular intervals on the upper surface of the vacuum suction unit 1 made of a porous material.
[0033]
The vacuum exhaust hole 3 is connected via a connection hose 6 to a vacuum pump 7 and a clean air supply device 8 capable of supplying clean air, and the connection hose 6 is provided with a switching valve 9.
[0034]
In the above vacuum suction device, when the sample 10, ie, the semiconductor wafer, is placed on the vacuum suction unit 1 and the switching valve 9 is switched to connect the vacuum pump 8 to the vacuum exhaust hole 3, the sample passes through the vacuum exhaust grooves 4, 4 '. Then, air is exhausted from the vacuum exhaust hole 3 as shown by an arrow, and air existing between the protrusion 2 and the back surface of the sample 10 is exhausted through a porous hole. As a result, the pressure between the sample 10 and the vacuum suction unit 1 decreases, and the sample 10 is pressed against the upper surface of the minute projection 2 by the atmospheric pressure, and the sample 10 is corrected to a flat surface. Next, the switching valve 9 is switched to disconnect the vacuum pump 7 from the vacuum exhaust hole 3, connect the clean air supply device 8 to the vacuum exhaust hole 3, and send clean air to the vacuum exhaust hole 3. Since the air blows out from the upper surface of the vacuum suction unit 1, the sample 10 is easily separated by air pressure. Then, the clean air is kept flowing until the next sample 10 is placed. In this state, when the sample 10 is placed on the upper surface of the vacuum suction unit 1 and the switching valve 9 is switched to connect the vacuum pump 7 and the vacuum exhaust hole 3, the sample 10 is vacuum-sucked.
[0035]
In the above-described embodiment, the pin-shaped minute projections 2 are provided as the projections. However, as the projections, a number of annular projections arranged on concentric circles as shown in FIG. 3 of JP-A-7-302832 are used. It may be provided. Further, in the above-described embodiment, the minute protrusions 2 having a circular cross section are provided, but minute protrusions having a rectangular cross section may be provided. Further, in the above-described embodiment, the circular vacuum suction unit 1 is provided, but a rectangular or elliptical vacuum suction unit may be provided. In the above-described embodiment, the vacuum suction unit 1 made of porous ceramics is used as the vacuum suction unit made of the porous material. However, the vacuum suction unit made of another porous material is used as the vacuum suction unit made of porous material. May be used.
[0036]
2 (a) and 2 (b) are a plan view and a front sectional view showing a third embodiment of the vacuum suction device according to the present invention.
In the third embodiment, on the upper surface of the vacuum suction unit 1 similar to the above, a porous material having a smaller pore diameter than the vacuum suction unit 1 is used. Are provided in a layered manner. The vacuum suction unit 1 and the protruding plate 102 are fixed by partial welding with a glass agent or fitting. Alternatively, it is formed by a mud casting method or the like.
[0037]
The protruding plate 102 is a porous ceramic material having a composition structure having a smaller pore diameter than the vacuum suction part 1, that is, a porosity of several tens to 40% at a maximum pore diameter of 1/2 or less of the projection diameter. It is formed of a porous ceramic material. The height of the projection 102a is set to an extremely low height of about 1 μm to 5 μm. The height of the base 102b is set to several hundreds μm to several mm or less in order to suppress the flow resistance of the air.
[0038]
In the description of the third embodiment, the same reference numerals are given to drawings corresponding to those of the first embodiment, and detailed description thereof is omitted.
[0039]
FIGS. 7A and 7B are a plan view and an AOA ′ sectional view showing a fourth embodiment of the vacuum suction device according to the present invention.
In the fourth embodiment, three holes 15 for passing a lift mechanism for lifting the sample 10 are provided at the center of the vacuum suction unit 1. The sample 10 is lifted upward through the hole 15, and the sample 10 is unloaded by a transfer arm inserted from the side. In the conventional ceramic vacuum pin chuck, the height of the projection was as large as several 100 μm. Therefore, a land portion for sealing the vacuum was provided around the hole 10 to prevent vacuum leakage. It is only necessary to seal the inner surface 17 (shown by a bold line in the AOA 'cross section) with a glass agent or a polymer resin, and it is not necessary to newly provide a land portion.
[0040]
FIGS. 8A and 8B are a plan view and an AOA ′ sectional view showing a fifth embodiment of the vacuum suction device according to the present invention.
In the fifth embodiment, three notches 16 are provided around the vacuum suction unit 1 for passing a lift mechanism for lifting the sample 10. The lift mechanism moves upward from below in the notch 16, and the sample 10 is lifted upward and carried out by the transfer arm for delivery inserted from the side. In the conventional ceramic vacuum pin chuck, the height of the projection was as large as several 100 μm. Therefore, a land portion for sealing vacuum was provided around the notch 16 to prevent vacuum leakage. It is only necessary to seal the side inner surface 18 (shown by oblique hatching in the AOA 'section) with a glass agent, a polymer resin, or the like, and it is not necessary to newly provide a land portion.
[0041]
【The invention's effect】
In the vacuum suction device according to the present invention, since the contact area between the upper surface of the projection and the back surface of the sample is extremely small, the influence of dust can be reduced, and the entire surface of the sample can be easily corrected to a highly accurate flat surface. Can be. Also, since the height of the projections is extremely low and can be formed on the pores of the porous material, the strength of the projections can be improved several times, and the durability can be increased. The formation of the projections arranged at intervals makes it possible to adsorb a sample thinner than 200 μm without deformation.
[Brief description of the drawings]
FIGS. 1 (a) and 1 (b) are a plan view and a front sectional view showing an example of a vacuum suction device constituting a vacuum suction device according to a second embodiment of the present invention.
FIGS. 2 (a) and 2 (b) are a plan view and a front sectional view showing one example of a vacuum suction device constituting a vacuum suction device according to a third embodiment of the present invention.
3 (a) and 3 (b) are a front view and a front sectional view of a conventional porous vacuum suction device.
4 (a) and 4 (b) are a front view and a front sectional view of a conventional porous vacuum suction device having a porous projection.
5 (a) and 5 (b) are an enlarged front view and an enlarged front sectional view of a conventional porous vacuum suction device having a porous projection.
FIGS. 6A and 6B are a plan view and a front sectional view showing one example of a vacuum suction device constituting the vacuum suction device according to the first embodiment of the present invention.
FIGS. 7A and 7B are a plan view and an AOA ′ cross-sectional view showing an example of a vacuum suction device constituting a vacuum suction device according to a fourth embodiment of the present invention.
FIGS. 8 (a) and (b) are a plan view and an AOA ′ sectional view showing an example of a vacuum suction device constituting a vacuum suction device according to a fifth embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Vacuum suction part, 2 ... Protrusion, 3 ... Vacuum exhaust hole, 4, 4 '... Vacuum exhaust groove, 5 ... Base, 6 ... Connection hose, 7 ... Vacuum pump, 8 ... Clean air supply device, 9 ... Switching valve Reference numeral 10: sample, 11: land, 12: minute gap, 14: vacuum adsorber, 15: hole through which the lift mechanism passes, 16: notch through which the lift mechanism passes, 17: side surface of the hole through which the lift mechanism passes, 18: lift Notch side surface through which the mechanism is passed, 102: projection plate, 102a: projection, 102b: base.

Claims

In a vacuum suction device provided with a vacuum suction device provided with a vacuum exhaust hole connected to a vacuum pump for supporting a sample only by a number of protrusions having an upper surface on the same plane,
The vacuum suction part communicating with the evacuation hole is made of a porous ceramic material having a maximum pore diameter of 1/2 or less of the diameter of the projection, and a large number of projections are provided on the upper surface thereof, and the height of the projection is about several μm. A minute gap is formed between the vacuum suction part and the sample by setting the height to an extremely low height.

In a vacuum suction device provided with a vacuum suction device provided with a vacuum exhaust hole connected to a vacuum pump for supporting a sample only by a number of protrusions having an upper surface on the same plane,
The vacuum suction part communicating with the vacuum exhaust hole is made of a porous material, and a number of projections made of a material having a smaller pore diameter than the vacuum suction part are fixedly provided on the upper surface of the vacuum suction part. A vacuum suction device, wherein a minute gap is formed between the vacuum suction part and the sample by setting the height to an extremely low height of about μm.

The vacuum suction portion is made of a porous ceramic material, and the projection is made of a dense material such as glass, metal, inorganic or organic material, and a porous ceramic material having a maximum pore diameter of 1/2 or less of the projection diameter. The vacuum suction device according to claim 2, wherein the vacuum suction device is made of a selected material.

In a vacuum suction device provided with a vacuum suction device provided with a vacuum exhaust hole connected to a vacuum pump for supporting a sample only by a number of protrusions having an upper surface on the same plane,
The vacuum suction part communicating with the vacuum exhaust hole was made of a porous material, and the upper surface thereof was made of a porous material having a smaller pore diameter than the vacuum suction part, and a number of protrusions were integrally formed on the upper surface of the thin plate-shaped base. A vacuum suction device characterized in that a projection plate is provided in a layer shape, and the height of the projection is set to an extremely low height of about several μm, thereby forming a minute gap between the vacuum suction portion and the sample. .

The vacuum suction part according to claim 4, wherein the vacuum suction part is made of a porous ceramic material, and the projection plate is made of a porous ceramic material having a maximum pore diameter of 1/2 or less of a projection diameter. apparatus.

The hole according to claim 1, wherein a hole for passing a mechanism for lifting the sample to be sucked to the vacuum suction part or a notch is provided in a peripheral part near the center of the vacuum suction part. Vacuum suction device.