JP4068742B2 - Method for producing anodized film-coated member for semiconductor production equipment having excellent heat cracking resistance and corrosion resistance - Google Patents

Method for producing anodized film-coated member for semiconductor production equipment having excellent heat cracking resistance and corrosion resistance Download PDF

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JP4068742B2
JP4068742B2 JP35352798A JP35352798A JP4068742B2 JP 4068742 B2 JP4068742 B2 JP 4068742B2 JP 35352798 A JP35352798 A JP 35352798A JP 35352798 A JP35352798 A JP 35352798A JP 4068742 B2 JP4068742 B2 JP 4068742B2
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anodized film
corrosion resistance
film
surface roughness
substrate
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JP2000178790A (en
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敏行 田中
淳 久本
秀仁 岡本
浩和 栗田
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Kobe Steel Ltd
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Kobe Steel Ltd
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Description

【0001】
【発明の属する技術分野】
本発明は、耐熱割れ性及び耐食性に優れた半導体製造装置用陽極酸化皮膜被覆部材に関し、詳細には半導体製造装置のチャンバやチャンバ内部材料などとして好適なアルミニウム合金製部材であって温度変化の大きい環境下で用いられても優れた耐熱割れ性を発揮すると共に、耐食性が良好な半導体製造装置用陽極酸化皮膜被覆部材に関するものである。
【0002】
【従来の技術】
例えば半導体製造装置用真空チャンバには主にアルミニウム合金が採用されているが、チャンバ内部は前処理工程や製造工程において室温〜200℃以上の環境下で様々な種類の腐食性ガス及びプラズマに曝されることから、無垢のアルミニウム合金のままでは耐食性や耐摩耗性を維持することが難しい。そこで、アルミニウム合金の耐食性及び耐摩耗性を向上させることを目的としてチャンバ内部に陽極酸化皮膜を形成する処理が一般的に行われている。この様に、アルミニウムまたはアルミニウム合金(以下、単にアルミニウム合金という)の耐食性及び耐摩耗性の向上を目的として、陽極酸化処理を行い、アルミニウム合金表面に陽極酸化皮膜を形成することは、通常採用されている技術であり、従来から種々の方法が提案されている。
【0003】
例えば、特開平9−217197号公報には、機械加工によって得られたアルミニウム合金表面の表面粗さRaが0.1μm以上の場合には、陽極酸化処理の際にアルミナが様々な方向に成長してストレスが大きくなり、陽極酸化皮膜中に欠陥(割れ)が生じてしまい、これが耐食性を著しく劣化させているとの観点から、基材表面に機械研磨を行うことによって表面平坦性を平均表面粗さRaを0.1μm以下(好ましくは0.01μm以下)にすることで、皮膜成長時のストレスを緩和させ耐食性を向上させる技術が開示されている。
【0004】
但し、この方法により得られた陽極酸化皮膜被覆部材であっても、チャンバ部材に用いた場合、使用中の大幅な温度変化により皮膜が割れたり剥離してしまい、皮膜内部へ腐食性物質が侵入することにより基材が腐食してしまうことが指摘されていた。
【0005】
上述の様に、従来の陽極酸化皮膜では必ずしも高温腐食環境と室温の熱サイクルを想定したものではなく、温度変化の大きい条件下で使用すると、基材と皮膜の熱膨張率の違いもあって皮膜の割れや剥離が生じ、腐食性物質が侵入することにより基材が腐食してしまうものであった。即ち、耐熱割れ性に優れた陽極酸化皮膜は存在しないのが実情である。
【0006】
【発明が解決しようとする課題】
本発明は上記事情に着目してなされたものであって、耐熱割れ性に優れ、しかも耐食性が良好な半導体製造装置用陽極酸化皮膜被覆部材を提供しようとするものである。
【0007】
【課題を解決するための手段】
上記課題を解決した本発明に係る耐熱割れ性及び耐食性に優れた半導体製造装置用陽極酸化皮膜被覆部材とは、AlまたはAl合金基材上に陽極酸化皮膜を有する陽極酸化皮膜被覆部材であって、下記(i),(ii)の方法により測定した表面粗さが0.1〜5μmのAlまたはAl合金基材に陽極酸化皮膜を形成することにより、該陽極酸化皮膜において複数のセルが結合したセル結合部が均一に分散してなることを要旨とするものである。
【0008】
(i) 基材表面で任意に選択した長さ25μmの線分上で3か所以上の表面粗さを測定し、得られた測定値の中から、最大値と最小値を除いた1か所以上の表面粗さの測定値(2か所以上の場合は平均値)を測定値Aとする。
(ii)この作業を3回以上繰り返し、上記測定値Aの平均を表面粗さとする。
【0009】
上記陽極酸化皮膜の表面についても、前記基材を用いれば前記(i),(ii)の方法により測定した表面粗さは0.1〜5μmとなる。
【0011】
また、陽極酸化皮膜の成長のプロセスにおいて両隣りのセルが合体して基材に至るか、或いは単独のセルが途中で分かれて基材に至っている陽極酸化皮膜を形成すれば耐熱割れ性及び耐食性に優れた半導体製造装置用陽極酸化皮膜被覆部材を得ることができる。
【0012】
【発明の実施の形態】
本発明者らは、従来の陽極酸化皮膜被覆部材に発生する割れを防止すべく、種々検討した結果、皮膜中の割れの現象が発生するのは、図1に示す様に、セル3の成長方向が1か所に集中してしまいストレスが非常に高くなる部分が皮膜2中に存在することが原因であるとの結論に達した。
【0013】
更に前記先行技術(特開平9−217197号公報)の様に、基材の平均表面粗さRaが0.1μm以下の陽極酸化皮膜に関しては、図2に示す様にセル3が基材に対して真っ直ぐ成長しており、セル3とセル3’の間のストレスは非常に小さいのであるが、高温(200℃以上)と室温の熱サイクルが与えられる真空チャンバ部材等の様な環境において使用すると、基材1と皮膜2との熱膨張率差を吸収できず、皮膜中の最も弱い部分であるセル3とセル3’との間で皮膜が割れてしまい、かえって耐食性を損なうものであることを突き止めた。
【0014】
そこで本発明者らは、皮膜割れの原因の一つである皮膜中のストレス集中部が局所的に存在することを避け、かつ基材と皮膜との熱膨張率差を吸収するため、セル結合部(陽極酸化処理におけるセルの成長過程で複数のセル同士が結合した部分)を皮膜中に一様に設ければ、皮膜中の弱い部分であるセル間を補強し、耐熱割れ性及び耐食性(特に耐ガス腐食性)に優れた皮膜を形成できることを見出し、本発明に想到した。
【0015】
即ち、本発明に係る陽極酸化皮膜被覆部材は、セル結合部を陽極酸化皮膜中に均一に分散させることでストレスを集中させることなく皮膜中に一様に分散させ、陽極酸化皮膜の耐熱割れ性及び耐食性を飛躍的に向上させるものである。
【0016】
上記の様な皮膜は、陽極酸化処理前の前記基材表面を下記(i),(ii)の方法により測定した表面粗さで0.1〜5μmとすることにより形成できる。
【0017】
(i) 基材表面で任意に選択した長さ25μmの線分上で3か所以上の表面粗さを測定し、得られた測定値の中から、最大値と最小値を除いた1か所以上の表面粗さの測定値(2か所以上の場合は平均値)を測定値Aとする。
(ii)この作業を3回以上繰り返し、上記測定値Aの平均を表面粗さとする。
【0018】
尚、図1に示すような従来品は、本発明で規定した方法で測定すると、たとえJIS規格(B0601)で測定したRa値では大きな値(特開平9−217197では従来技術としてRa0.1〜0.8μmのものが挙げられている)が得られているものであっても、0.1μm以下の値(平滑な表面の値)が得られる。JISで定義するRaにおいて値が大きくなる理由は、長さ数mmの区間を測定することで機械加工目のような大きな幅をもつ粗さまで併せて平均してしまうからである。本発明で規定する表面粗さは、長さ25μmの区間で平均粗さを測定し、かつ最大値及び最小値を除いて平均するという測定方法に基づくものであり、上記Ra値で表現されるようなマクロな表面形状ではなく、ミクロな表面形状を規定している。換言すれば、本発明は、耐熱割れ性に優れた皮膜を形成するには、Raで表現されるようなマクロな表面形状ではなく、もっとミクロな表面形状を制御することが非常に有効であるとの知見に基づいてなされたものである。
【0019】
本発明で規定する表面粗さが0.1μm未満であると、表面は平滑な状態に近くなり、セルが真っ直ぐ成長して耐熱割れ性が劣化するので、0.1μm以上にすることが必要であり、0.2μm以上であれば望ましい。一方、本発明で規定する表面粗さが5μmを超えると、基材が過度にあれた状態となり、陽極酸化皮膜中に欠陥が多く発生し、やはり耐熱割れ性及び耐食性が劣化するので5μm以下とすることが必要であり、3μm以下であれば望ましい。
【0020】
本発明で規定する表面粗さを得るには、Al合金の種類や、部材の種類や使用環境等によって適切な方法を選択すればよく、例えば、ショットブラスト,機械研磨,圧延といった物理的手法や、エッチング等の化学的手法に基づいて基材表面を処理すればよい。
【0021】
本発明に係る陽極酸化皮膜被覆部材は、まずAl合金基材表面に本発明で規定する表面粗さで0.1〜5μmに粗面化し[図3(a)参照]、次いで常法に従い陽極酸化皮膜を形成すれば図3(b)に示す様に、皮膜内部にセル結合部が分散した皮膜を得ることができる。上記陽極酸化皮膜は、セルの成長プロセスにおいて両隣りのセルが合体して基材に至るか、或いは単独のセルが途中で分かれて基材に至っているものである。尚、陽極酸化皮膜表面は、陽極酸化処理前における基材表面の形状とほぼ同じであるが、図3(c)に示す様に、この表面を研磨して平滑化しても差し支えない。また、本発明で規定する表面粗さは、あくまでも陽極酸化処理前の基材表面で制御することが不可欠であり、例えば図4に示す様に、0.1μm未満の表面粗さの基材を陽極酸化して、その陽極酸化皮膜の表面を本発明で規定する表面粗さで0.1〜5μmに形成したとしても熱割れは発生するものである。
【0022】
陽極酸化皮膜の膜厚は、薄過ぎると耐食性の向上効果が十分に発揮されないので0.1μm以上とするのが適当であり、0.5μm以上が好ましく、1μm以上であればより好ましい。また陽極酸化皮膜が厚過ぎると、皮膜が剥離し易くなるので200μm以下が適当であり、70μm以下が好ましく、50μm以下であればより好ましい。
【0023】
本発明が好適に用いられるチャンバ内部材とは、AlまたはAl合金製真空チャンバの構造材だけではなく、該真空チャンバ内に配設されるガス拡散プレート(GDP),クランパー,シャワーヘッド,サセプター,クランプリング,静電チャックなどの部材であって、AlまたはAl合金で製作されるものには全て適用可能である。
【0024】
本発明は基材となるAl合金を限定する訳ではないが、例えばチャンバ材料としては機械的強度,熱伝導率,電気伝導率,耐食性の観点で優れている1000系合金や5000系合金,6000系合金が望ましい。1000系合金は純アルミニウム系であるが、5000系合金の場合には、少なくとも合金成分としてSi:0.5重量%以下,Mg:0.5〜6.0重量%を含有していることが好ましく、また6000系合金の場合には、少なくとも合金成分としてSi:0.2〜1.2重量%、Mg:0.4〜1.5重量%を含有していることが好ましい。尚、チャンバ内部材の場合には、5000系合金や6000系合金の他に、2000系合金や7000系合金などを用いることもできる。また、Al合金の合金成分として、Mg,Si,Cu,Fe等を含有することにより、高周波や高温(熱サイクル)に対する陽極酸化皮膜の耐割れ性向上、酸化膜内部応力の低減にも効果を発揮することが分かっている。特に6000系合金の成分元素であるMg,Siがあると効果的であり、材料の最終熱処理条件によってその効果が影響を受ける場合がある。
【0025】
尚、本発明において陽極酸化処理を行う際の電解電圧は一定であってもよいが、上記終期電圧を初期電圧より高く設定して、基材側ポア径を表面側ポア径より大きくすることが推奨される。その理由は、表面側におけるポア径は、優れた耐プラズマ性を得る上で小さい程好ましく、一方ポーラス層の基材側の内部構造は、耐ガス腐食性を向上させるという観点からポア径及びセル径の大きな構造が望ましいからである。具体的には、陽極酸化の初期電圧は50V以下が好ましく、30V以下であればより好ましい。一方、陽極酸化処理の終期電圧は初期電圧よりも高く設定することが望ましいが、具体的には30V以上が好ましく、50V以上がより望ましく、70V以上であれば更に好ましい。
【0026】
陽極酸化処理における終期電圧を初期電圧より高く設定するにあたっては、陽極酸化電圧を全工程に亘って連続的に変化させる方法と段階的に変化させる方法が挙げられる。換言すれば、陽極酸化電圧を全工程の任意の区間で連続的に及び/又は非連続的に変化させてもよく、或いは全工程の任意の区間において前記変化部分を含みながら他の任意の区間で電圧を一定に保ってもよい。この様に、陽極酸化皮膜を形成する際の陽極酸化電圧を全工程の任意の区間で変化させて異なった内部構造を有する層を複合又は積層することにより、プロセス中で陽極酸化皮膜とガス又はプラズマが接触した場合に生ずる応力や体積変化を緩和することができ、その結果、腐食や損傷の起点となる皮膜の割れや剥離を抑制して耐ガス腐食性および耐プラズマ性の向上に効果を発揮することが期待できる。
【0027】
また本発明においてAl合金製基材に陽極酸化皮膜を形成するにあたっては、C,S,N,P,F,Bよりなる群から選ばれる1種以上の元素を含有させた溶液で電解を行うことが推奨され、例えば、しゅう酸,りん酸,ほう酸またはその化合物、フタル酸またはその化合物よりなる群から選ばれる1種以上を含む水溶液を用いて電解を行うことが望ましい。
【0028】
更には、まずポーラス型陽極酸化処理を施し、次いで非ポーラス型陽極酸化処理を行うことをが推奨される。尚、上記ポーラス型陽極酸化処理とは、JIS H 0201のアルミニウム表面処理用語における陽極酸化皮膜細胞を形成する通常の陽極酸化処理を言い、電解溶液として硫酸,りん酸,しゅう酸,クロム酸のいずれかを用いるか、或はこれらの混合溶液を用いて、5〜200Vの電解電圧で陽極酸化処理を施せばよい。また上記非ポーラス型陽極酸化処理とは、ポアを形成することなくバリア層を成長させる陽極酸化処理をいい、具体的には、ほう酸系溶液,りん酸系溶液,フタル酸系溶液,アジピン酸系溶液,炭酸系溶液,クエン酸溶液,酒石酸溶液,クロム酸ナトリウム溶液などのいずれかを用いるか、或はこれらの混合溶液を用いて、60〜500Vの電解電圧で陽極酸化処理する方法等が例示できる。
【0029】
Al合金製基材としては、晶出物及び析出物の平均粒径が10μm以下であるか、或は上記晶出物及び析出物が、部材表面中最大面積を有する部材表面に対して平行に配列される様に調整されたAl合金材料を用いることによって、陽極酸化皮膜の耐食性に加えて基材自体の耐食性も期待できる。また、晶出物及び析出物の平均粒径が10μm以下であり、且つ晶出物及び析出物の配列方向が最大面積を有する部材表面に対して平行であることが好ましい。上記晶出物及び析出物の体積分率としては、2%以下であることが推奨される。
【0030】
以下、本発明を実施例によって更に詳細に説明するが、下記実施例は本発明を限定する性質のものではなく、前・後記の主旨に徴して設計変更することはいずれも本発明の技術的範囲内に含まれるものである。
【0031】
【実施例】
実施例1
5000系または6000系のAl合金からなる基材表面に、ショットブラストを施すことにより、表1に示す表面粗さとし、表1に併記する各種の電解溶液を用いて陽極酸化処理を行い、各種試験片を作製した。得られた試験片に下記の試験を行い、耐熱割れ性と耐ガス腐食性を評価した。
【0032】
[耐熱割れ試験]
450℃で1時間加熱後、大気中に24時間暴露する熱サイクルを3セット繰り返し、任意の10cm2 の領域における割れの長さを測定して、以下の様に評価した。
◎:割れなし
○:割れ長さ80mm未満
△:割れ長さ80mm以上160mm未満
×:割れ長さ160mm以上
【0033】
[耐ガス腐食試験]
400℃で4時間加熱後、大気中に24時間暴露する熱サイクルを2セット繰り返し、腐食の発生した面積率を測定して、以下の様に評価した。
◎:腐食発生なし
○:腐食発生面積率 10%未満
△:腐食発生面積率 10%以上 20%未満
×:腐食発生面積率 20%以上
結果は、表1に示す。
【0034】
【表1】

Figure 0004068742
【0035】
No.1〜7は本発明に係る陽極酸化皮膜被覆部材であり、いずれも耐熱割れ性及び耐ガス腐食性に優れている。一方、No.8〜11は、本発明で規定する表面粗さが大き過ぎるか、小さ過ぎる場合の比較例であり、いずれも耐熱割れ性及び耐ガス腐食性に劣ることが分かる。
【0036】
実施例2
陽極酸化処理後の表面において、本発明で規定する表面粗さを測定したこと以外は、実施例1と同様にして表2に示す各種試験片を作製し、耐熱割れ性と耐ガス腐食性を評価した。結果は表2に併記する。
【0037】
【表2】
Figure 0004068742
【0038】
No.1〜4は本発明に係る陽極酸化皮膜被覆部材であり、いずれも耐熱割れ性及び耐ガス腐食性に優れている。一方、No.5〜8は、本発明で規定する表面粗さが大き過ぎるか、小さ過ぎる場合の比較例であり、いずれも耐熱割れ性及び耐ガス腐食性に劣ることが分かる。
【0039】
尚、No.9は、図4で示した様に、本発明範囲外の平滑な表面を有する基材に陽極酸化皮膜を形成した後、ブラスト処理で表面を粗くしたものであり、この場合も、耐熱割れ性及び耐ガス腐食性に劣ることが分かる。
【0040】
実施例3
6000系のAl合金からなる基材表面に、ショットブラストまたは表面研磨を施すことにより、表3に示す図1〜図4の内部構造を有する陽極酸化皮膜を形成した。得られた試験片に実施例1と同じ試験を行い、耐熱割れ性と耐ガス腐食性を評価した。結果は表3に示す。
【0041】
【表3】
Figure 0004068742
【0042】
No.1,2は本発明に係る陽極酸化皮膜被覆部材であり、いずれも耐熱割れ性及び耐ガス腐食性に優れている。一方、No.3〜5は、陽極酸化皮膜においてセル結合部が均一に分散していない比較例であり、いずれも耐熱割れ性及び耐ガス腐食性に劣ることが分かる。
【0043】
【発明の効果】
本発明は以上の様に構成されているので、耐熱割れ性に優れ、しかも耐食性が良好な半導体製造装置用陽極酸化皮膜被覆部材が提供できることとなった。
【図面の簡単な説明】
【図1】従来の陽極酸化皮膜の構造を示す概略説明図である。
【図2】従来の陽極酸化皮膜の構造を示す概略説明図である。
【図3】本発明に係る陽極酸化皮膜の構造を示す概略説明図である。
【図4】比較例の陽極酸化皮膜の構造を示す概略説明図である。
【符号の説明】
1 基材
2 皮膜
3 セル[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to an anodized film-coated member for a semiconductor manufacturing apparatus excellent in heat cracking resistance and corrosion resistance, and more specifically, is an aluminum alloy member suitable as a chamber of a semiconductor manufacturing apparatus or a chamber internal material, and has a large temperature change. The present invention relates to an anodized film-coated member for a semiconductor manufacturing apparatus that exhibits excellent heat cracking resistance even when used in an environment and has good corrosion resistance.
[0002]
[Prior art]
For example, aluminum alloys are mainly used in vacuum chambers for semiconductor manufacturing equipment, but the interior of the chamber is exposed to various types of corrosive gases and plasmas in an environment of room temperature to 200 ° C. or higher in pretreatment processes and manufacturing processes. Therefore, it is difficult to maintain corrosion resistance and wear resistance with a solid aluminum alloy. Therefore, a process of forming an anodized film inside the chamber is generally performed for the purpose of improving the corrosion resistance and wear resistance of the aluminum alloy. As described above, it is usually employed to form an anodic oxide film on the surface of an aluminum alloy by performing anodizing treatment for the purpose of improving the corrosion resistance and wear resistance of aluminum or an aluminum alloy (hereinafter simply referred to as an aluminum alloy). In the past, various methods have been proposed.
[0003]
For example, in JP-A-9-217197, when the surface roughness Ra of the aluminum alloy surface obtained by machining is 0.1 μm or more, alumina grows in various directions during the anodizing treatment. From the viewpoint that the stress increases and defects (cracks) occur in the anodized film, which significantly deteriorates the corrosion resistance, the surface flatness is averaged by performing mechanical polishing on the substrate surface. A technique for reducing the stress during film growth and improving the corrosion resistance by reducing the thickness Ra to 0.1 μm or less (preferably 0.01 μm or less) is disclosed.
[0004]
However, even if an anodic oxide coating member obtained by this method is used for a chamber member, the coating cracks or peels off due to a significant temperature change during use, and corrosive substances enter the coating. It has been pointed out that the base material is corroded by doing so.
[0005]
As mentioned above, conventional anodic oxide films do not necessarily assume a high-temperature corrosive environment and a thermal cycle at room temperature. When used under conditions with large temperature changes, there is a difference in the coefficient of thermal expansion between the substrate and the film. The film was cracked or peeled off, and the base material was corroded by the entry of corrosive substances. That is, there is actually no anodic oxide film with excellent heat cracking resistance.
[0006]
[Problems to be solved by the invention]
The present invention has been made paying attention to the above circumstances, and an object of the present invention is to provide an anodized film-coated member for a semiconductor manufacturing apparatus that has excellent heat cracking resistance and good corrosion resistance.
[0007]
[Means for Solving the Problems]
The anodic oxide coating member for a semiconductor manufacturing apparatus excellent in heat cracking resistance and corrosion resistance according to the present invention that solves the above problems is an anodic oxide coating member having an anodic oxide coating on an Al or Al alloy substrate. By forming an anodized film on an Al or Al alloy substrate having a surface roughness of 0.1 to 5 μm measured by the following methods (i) and (ii), a plurality of cells are bonded in the anodized film. The gist of the present invention is that the cell coupling portions are uniformly dispersed.
[0008]
(i) Measure the surface roughness at three or more locations on a line segment of 25 μm length arbitrarily selected on the surface of the substrate, and remove the maximum and minimum values from the measured values. The measurement value A is the measured value of the surface roughness of at least the place (in the case of two or more places, the average value).
(ii) This operation is repeated three times or more, and the average of the measured value A is defined as the surface roughness.
[0009]
As for the surface of the anodic oxide film, the surface roughness measured by the methods (i) and (ii) is 0.1 to 5 μm when the substrate is used.
[0011]
Also, in the process of growth of the anodic oxide film, both adjacent cells merge to reach the base material, or if an anodic oxide film is formed in which a single cell is divided in the middle to reach the base material, heat cracking resistance and corrosion resistance It is possible to obtain an anodic oxide coating member for a semiconductor manufacturing apparatus that is excellent in performance.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
As a result of various investigations to prevent cracks occurring in the conventional anodized film-coated member, the present inventors have found that the phenomenon of cracks in the film occurs as shown in FIG. It has been concluded that the cause is that the part where the direction is concentrated in one place and the stress becomes very high is present in the film 2.
[0013]
Further, as in the above prior art (Japanese Patent Laid-Open No. 9-217197), for an anodized film having an average surface roughness Ra of 0.1 μm or less, the cell 3 is attached to the substrate as shown in FIG. Although the stress between the cell 3 and the cell 3 ′ is very small, when used in an environment such as a vacuum chamber member that is subjected to a high temperature (200 ° C. or higher) and a room temperature thermal cycle, etc. The difference in thermal expansion coefficient between the substrate 1 and the film 2 cannot be absorbed, and the film is broken between the cell 3 and the cell 3 ′, which is the weakest part of the film, and the corrosion resistance is impaired. I found out.
[0014]
Therefore, the present inventors have avoided cell stress locally in the film, which is one of the causes of film cracking, and absorbs the difference in thermal expansion coefficient between the substrate and the film, so If the part (part where a plurality of cells are combined in the cell growth process in the anodizing process) is uniformly provided in the film, the cells, which are weak parts in the film, are reinforced, and heat cracking and corrosion resistance ( In particular, the inventors have found that a film excellent in gas corrosion resistance) can be formed, and have arrived at the present invention.
[0015]
That is, the anodic oxide coating member according to the present invention uniformly disperses the cell bonding portion in the anodic oxide film without uniformly concentrating the stress in the anodic oxide film. In addition, the corrosion resistance is drastically improved.
[0016]
The film as described above can be formed by setting the surface of the base material before the anodizing treatment to a surface roughness of 0.1 to 5 μm as measured by the following methods (i) and (ii).
[0017]
(i) Measure the surface roughness at three or more locations on a line segment of 25 μm length arbitrarily selected on the surface of the substrate, and remove the maximum and minimum values from the measured values. The measurement value A is the measured value of the surface roughness of at least the place (in the case of two or more places, the average value).
(ii) This operation is repeated three times or more, and the average of the measured value A is defined as the surface roughness.
[0018]
Incidentally, when the conventional product as shown in FIG. 1 is measured by the method defined in the present invention, even if the Ra value measured by the JIS standard (B0601) is large (in Japanese Patent Application Laid-Open No. 9-217197, Ra 0.1 A value of 0.1 μm or less (smooth surface value) can be obtained. The reason why the value increases in Ra defined by JIS is that the roughness having a large width such as a machined eye is averaged by measuring a section having a length of several mm. The surface roughness defined in the present invention is based on a measurement method in which an average roughness is measured in a section having a length of 25 μm and averaged except for a maximum value and a minimum value, and is expressed by the Ra value. It defines not a macro surface shape but a micro surface shape. In other words, in the present invention, it is very effective to control a microscopic surface shape, not a macroscopic surface shape represented by Ra, in order to form a film having excellent heat cracking resistance. It was made based on the knowledge.
[0019]
When the surface roughness specified in the present invention is less than 0.1 μm, the surface becomes close to a smooth state, and the cell grows straight and the heat cracking resistance deteriorates. Yes, 0.2 μm or more is desirable. On the other hand, when the surface roughness specified in the present invention exceeds 5 μm, the substrate is excessively exposed, many defects are generated in the anodized film, and the heat cracking resistance and corrosion resistance are deteriorated, so that it is 5 μm or less. 3 μm or less is desirable.
[0020]
In order to obtain the surface roughness defined in the present invention, an appropriate method may be selected depending on the type of Al alloy, the type of member, the usage environment, and the like. For example, physical methods such as shot blasting, mechanical polishing, and rolling, The substrate surface may be treated based on a chemical method such as etching.
[0021]
The anodized film-coated member according to the present invention is first roughened on the surface of an Al alloy substrate to a surface roughness specified by the present invention to 0.1 to 5 μm [see FIG. If an oxide film is formed, as shown in FIG. 3B, it is possible to obtain a film in which cell coupling portions are dispersed inside the film. In the cell growth process, the anodic oxide film is a cell in which both adjacent cells are united to reach the base material, or a single cell is divided on the way to the base material. The surface of the anodized film is almost the same as the shape of the substrate surface before the anodizing treatment. However, as shown in FIG. 3C, the surface may be polished and smoothed. In addition, it is indispensable to control the surface roughness defined in the present invention only on the surface of the substrate before the anodizing treatment. For example, as shown in FIG. 4, a substrate having a surface roughness of less than 0.1 μm is used. Even when anodized and the surface of the anodized film is formed to a surface roughness of 0.1 to 5 μm as defined in the present invention, thermal cracking occurs.
[0022]
If the thickness of the anodic oxide film is too thin, the effect of improving the corrosion resistance is not sufficiently exhibited. Therefore, the thickness is suitably 0.1 μm or more, preferably 0.5 μm or more, and more preferably 1 μm or more. Further, if the anodized film is too thick, the film is easily peeled off, so that it is suitably 200 μm or less, preferably 70 μm or less, and more preferably 50 μm or less.
[0023]
The chamber internal member to which the present invention is preferably used is not only a structural material of a vacuum chamber made of Al or Al alloy, but also a gas diffusion plate (GDP), a clamper, a shower head, a susceptor disposed in the vacuum chamber, All of the members such as a clamp ring and an electrostatic chuck that are made of Al or an Al alloy are applicable.
[0024]
The present invention does not limit the Al alloy used as the base material. For example, the chamber material is excellent in terms of mechanical strength, thermal conductivity, electrical conductivity, and corrosion resistance. A system alloy is desirable. 1000 series alloy is pure aluminum series, but in the case of 5000 series alloy, it should contain at least Si: 0.5% by weight or less and Mg: 0.5-6.0% by weight as alloy components. Preferably, in the case of a 6000 series alloy, it is preferable to contain at least Si: 0.2 to 1.2% by weight and Mg: 0.4 to 1.5% by weight as alloy components. In the case of an in-chamber member, a 2000 series alloy or a 7000 series alloy can be used in addition to the 5000 series alloy or 6000 series alloy. In addition, by containing Mg, Si, Cu, Fe, etc. as the alloy component of the Al alloy, it is effective in improving the crack resistance of the anodized film against high frequency and high temperature (thermal cycle) and reducing the internal stress of the oxide film. I know it will work. In particular, Mg and Si, which are constituent elements of a 6000 series alloy, are effective, and the effect may be affected by the final heat treatment conditions of the material.
[0025]
In the present invention, the electrolysis voltage at the time of anodizing may be constant, but the final voltage may be set higher than the initial voltage to make the substrate-side pore diameter larger than the surface-side pore diameter. Recommended. The reason is that the pore diameter on the surface side is preferably as small as possible in order to obtain excellent plasma resistance, while the internal structure on the substrate side of the porous layer has a pore diameter and cell from the viewpoint of improving gas corrosion resistance. This is because a structure having a large diameter is desirable. Specifically, the initial voltage for anodic oxidation is preferably 50 V or less, and more preferably 30 V or less. On the other hand, the final voltage of the anodic oxidation treatment is desirably set higher than the initial voltage. Specifically, it is preferably 30 V or higher, more preferably 50 V or higher, and even more preferably 70 V or higher.
[0026]
In setting the final voltage in the anodizing process higher than the initial voltage, there are a method of changing the anodizing voltage continuously throughout the whole process and a method of changing it stepwise. In other words, the anodic oxidation voltage may be changed continuously and / or discontinuously in any section of the whole process, or any other section including the changed part in any section of the whole process. The voltage may be kept constant. In this way, the anodizing voltage when forming the anodized film is changed in an arbitrary section of the entire process, and the layers having different internal structures are combined or laminated, so that the anodized film and the gas or Stress and volume changes caused by plasma contact can be alleviated, and as a result, cracking and peeling of the film, which is the starting point of corrosion and damage, can be suppressed to improve gas corrosion resistance and plasma resistance. We can expect to show.
[0027]
In the present invention, when an anodized film is formed on an Al alloy substrate, electrolysis is performed with a solution containing one or more elements selected from the group consisting of C, S, N, P, F, and B. For example, it is desirable to perform electrolysis using an aqueous solution containing at least one selected from the group consisting of oxalic acid, phosphoric acid, boric acid or a compound thereof, phthalic acid or a compound thereof.
[0028]
Furthermore, it is recommended to first perform a porous type anodizing treatment and then perform a non-porous type anodizing treatment. The porous type anodizing treatment means a normal anodizing treatment for forming anodized film cells in terms of aluminum surface treatment in JIS H 0201, and any one of sulfuric acid, phosphoric acid, oxalic acid and chromic acid as an electrolytic solution. Or using these mixed solutions may be anodized at an electrolytic voltage of 5 to 200V. The non-porous type anodizing treatment refers to anodizing treatment for growing a barrier layer without forming pores. Specifically, boric acid solution, phosphoric acid solution, phthalic acid solution, adipic acid solution Examples include a method of anodizing at an electrolytic voltage of 60 to 500 V using any one of a solution, a carbonic acid solution, a citric acid solution, a tartaric acid solution, a sodium chromate solution, or a mixed solution thereof. it can.
[0029]
As the Al alloy base material, the average particle size of the crystallized product and the precipitate is 10 μm or less, or the crystallized product and the precipitate are parallel to the member surface having the largest area in the member surface. By using the Al alloy material adjusted so as to be arranged, the corrosion resistance of the substrate itself can be expected in addition to the corrosion resistance of the anodized film. Moreover, it is preferable that the average particle diameter of a crystallized substance and a precipitate is 10 micrometers or less, and the arrangement direction of a crystallized substance and a precipitate is parallel to the member surface which has the largest area. The volume fraction of the crystallized product and the precipitate is recommended to be 2% or less.
[0030]
Hereinafter, the present invention will be described in more detail by way of examples. However, the following examples are not of a nature that limits the present invention, and any design changes may be made in accordance with the gist of the present invention. It is included in the range.
[0031]
【Example】
Example 1
By subjecting the surface of a base material made of a 5000-series or 6000-series Al alloy to shot blasting, the surface roughness shown in Table 1 is obtained, and anodization treatment is performed using various electrolytic solutions listed in Table 1. A piece was made. The obtained test pieces were subjected to the following tests to evaluate the heat cracking resistance and gas corrosion resistance.
[0032]
[Heat cracking test]
After heating at 450 ° C. for 1 hour, the heat cycle exposed to the atmosphere for 24 hours was repeated three times, and the crack length in an arbitrary region of 10 cm 2 was measured and evaluated as follows.
◎: No cracking ○: Crack length less than 80 mm Δ: Crack length of 80 mm or more and less than 160 mm ×: Crack length of 160 mm or more
[Gas corrosion resistance test]
After heating at 400 ° C. for 4 hours, two sets of thermal cycles exposed to the atmosphere for 24 hours were repeated, and the area ratio at which corrosion occurred was measured and evaluated as follows.
◎: No corrosion occurrence ○: Corrosion occurrence area ratio less than 10% Δ: Corrosion occurrence area ratio 10% or more and less than 20% ×: Corrosion occurrence area ratio 20% or more The results are shown in Table 1.
[0034]
[Table 1]
Figure 0004068742
[0035]
No. 1 to 7 are anodized film-coated members according to the present invention, and all are excellent in heat cracking resistance and gas corrosion resistance. On the other hand, no. 8 to 11 are comparative examples in which the surface roughness specified in the present invention is too large or too small, and it is understood that both are inferior in heat cracking resistance and gas corrosion resistance.
[0036]
Example 2
Except that the surface roughness defined in the present invention was measured on the surface after the anodizing treatment, various test pieces shown in Table 2 were prepared in the same manner as in Example 1, and the heat crack resistance and gas corrosion resistance were measured. evaluated. The results are also shown in Table 2.
[0037]
[Table 2]
Figure 0004068742
[0038]
No. 1-4 are anodized film-coated members according to the present invention, and all are excellent in heat cracking resistance and gas corrosion resistance. On the other hand, no. Nos. 5 to 8 are comparative examples in which the surface roughness specified in the present invention is too large or too small, and it is understood that both are inferior in heat cracking resistance and gas corrosion resistance.
[0039]
No. As shown in FIG. 4, after forming an anodic oxide film on a base material having a smooth surface outside the scope of the present invention, the surface is roughened by blasting, and in this case as well, heat cracking resistance It can also be seen that the gas corrosion resistance is poor.
[0040]
Example 3
An anodic oxide film having the internal structure of FIGS. 1 to 4 shown in Table 3 was formed by performing shot blasting or surface polishing on the surface of a base material made of a 6000 series Al alloy. The obtained test piece was subjected to the same test as in Example 1 to evaluate heat cracking resistance and gas corrosion resistance. The results are shown in Table 3.
[0041]
[Table 3]
Figure 0004068742
[0042]
No. 1 and 2 are anodized film-coated members according to the present invention, both of which are excellent in heat cracking resistance and gas corrosion resistance. On the other hand, no. Nos. 3 to 5 are comparative examples in which the cell bonding portions are not uniformly dispersed in the anodized film, and it is understood that all are inferior in heat cracking resistance and gas corrosion resistance.
[0043]
【The invention's effect】
Since the present invention is configured as described above, it is possible to provide an anodized film-coated member for a semiconductor manufacturing apparatus that has excellent heat cracking resistance and good corrosion resistance.
[Brief description of the drawings]
FIG. 1 is a schematic explanatory view showing the structure of a conventional anodic oxide film.
FIG. 2 is a schematic explanatory view showing the structure of a conventional anodic oxide film.
FIG. 3 is a schematic explanatory view showing the structure of an anodized film according to the present invention.
FIG. 4 is a schematic explanatory view showing the structure of a comparative anodized film.
[Explanation of symbols]
1 Base material 2 Coating 3 Cell

Claims (2)

AlまたはAl合金基材上に陽極酸化皮膜を有する陽極酸化皮膜被覆部材の製造方法であって、前記基材の表面粗さを、下記(i),(ii)の方法により測定した表面粗さが0.1〜5μmとなるように表面処理する工程と、前記基材に陽極酸化処理を行なう工程とを含むことを特徴とする耐熱割れ性及び耐食性に優れた半導体製造装置用陽極酸化皮膜被覆部材の製造方法。
(i)基材表面で任意に選択した長さ25μmの線分上で3か所以上の表面粗さを測定し、得られた測定値の中から、最大値と最小値を除いた1か所以上の表面粗さの測定値(2か所以上の場合は平均値)を測定値Aとする。
(ii)この作業を3回以上繰り返し、上記測定値Aの平均を表面粗さとする。
A method for producing an anodized film-coated member having an anodized film on an Al or Al alloy substrate, wherein the surface roughness of the substrate is measured by the following methods (i) and (ii) An anodized film coating for a semiconductor manufacturing apparatus excellent in heat cracking resistance and corrosion resistance, comprising a step of performing a surface treatment so as to be 0.1 to 5 μm and a step of anodizing the base material Manufacturing method of member.
(i) Measure the surface roughness at 3 or more locations on a line segment of 25 μm length arbitrarily selected on the surface of the substrate, and remove the maximum and minimum values from the measured values. The measurement value A is the measured value of the surface roughness of at least the place (in the case of two or more places, the average value).
(ii) This operation is repeated three times or more, and the average of the measured value A is defined as the surface roughness.
前記基材を表面処理する方法が、ショットブラスト、機械研磨、圧延、エッチングのいずれかである請求項に記載の半導体製造装置用陽極酸化皮膜被覆部材の製造方法。The method for producing an anodized film-coated member for a semiconductor production apparatus according to claim 1 , wherein a method of surface-treating the substrate is any one of shot blasting, mechanical polishing, rolling, and etching.
JP35352798A 1998-12-11 1998-12-11 Method for producing anodized film-coated member for semiconductor production equipment having excellent heat cracking resistance and corrosion resistance Expired - Lifetime JP4068742B2 (en)

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US9663870B2 (en) 2013-11-13 2017-05-30 Applied Materials, Inc. High purity metallic top coat for semiconductor manufacturing components
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