JP3953760B2 - Micro-processing method of glass substrate, glass substrate for micro-processing, and micro-processed glass product - Google Patents

Micro-processing method of glass substrate, glass substrate for micro-processing, and micro-processed glass product Download PDF

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JP3953760B2
JP3953760B2 JP2001267123A JP2001267123A JP3953760B2 JP 3953760 B2 JP3953760 B2 JP 3953760B2 JP 2001267123 A JP2001267123 A JP 2001267123A JP 2001267123 A JP2001267123 A JP 2001267123A JP 3953760 B2 JP3953760 B2 JP 3953760B2
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glass substrate
glass
compressive stress
processing method
content
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JP2003073145A (en
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宏之 猪又
淳史 倉知
一石 三谷
靖弘 斉藤
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Nippon Sheet Glass Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
    • C03C3/095—Glass compositions containing silica with 40% to 90% silica, by weight containing rare earths
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C15/00—Surface treatment of glass, not in the form of fibres or filaments, by etching
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
    • C03C3/083—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound
    • C03C3/085—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound containing an oxide of a divalent metal
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
    • C03C3/083—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound
    • C03C3/085—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound containing an oxide of a divalent metal
    • C03C3/087—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound containing an oxide of a divalent metal containing calcium oxide, e.g. common sheet or container glass
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
    • C03C3/089—Glass compositions containing silica with 40% to 90% silica, by weight containing boron
    • C03C3/091—Glass compositions containing silica with 40% to 90% silica, by weight containing boron containing aluminium
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
    • C03C3/089—Glass compositions containing silica with 40% to 90% silica, by weight containing boron
    • C03C3/091—Glass compositions containing silica with 40% to 90% silica, by weight containing boron containing aluminium
    • C03C3/093—Glass compositions containing silica with 40% to 90% silica, by weight containing boron containing aluminium containing zinc or zirconium
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C2204/00—Glasses, glazes or enamels with special properties
    • C03C2204/08—Glass having a rough surface

Description

【０００１】
【発明の属する技術分野】
本発明は、ガラス基材の微細加工方法、微細加工用ガラス基材及び微細加工ガラス製品に関する。さらに詳しくは、本発明は、ガラス基材の表面及びその近傍にエッチングレートが他の部分と異なる領域を形成し、他の部分とのエッチングレートの差を利用して化学的エッチング処理により、ガラス基材表面に凸形状を形成させるガラス基材の微細加工方法、ガラス基材表面に凸形状を形成させる微細加工方法に好適に使用し得る微細加工用ガラス基材、及び前記微細加工方法によって得られ、回折格子やマイクロレンズなどの微小光学素子などとして好適な微細加工ガラス製品に関するものである。
【０００２】
【従来の技術】
近年、情報技術（ＩＴ）などの産業技術革命に伴い、ガラス表面をμｍやｎｍのオーダーで微細加工する技術が要求されるようになってきた。例えば種々の光学装置に用いられるマイクロレンズ、マイクロプリズム、回折格子などの微小光学素子においては、μｍオーダーで制御された凹凸パターンを形成したものが求められている。そして、ガラス表面に、このようなμｍオーダーで制御された凹凸パターンを形成させる加工方法としては、従来、（１）金型に樹脂層やゾルーゲル膜を介してガラス基板を押し当て、硬化させて金型の形状を転写させるエンボス法、（２）レーザービームやイオンビームなどで直接にガラス基板をドライエッチングする方法、（３）ガラス基板表面に設けられたフォトレジスト膜に選択露光を施し、現像処理してレジストパターンを形成し、このレジストパターンをマスクとしてエッチングするフォトリソグラフィー法など、様々な加工方法が検討されている。しかしながら、前記（１）の樹脂層やゾルーゲル膜を用いるエンボス法は、材料面から見て耐熱性が不充分であり、また（２）のレーザービームやイオンビームによるエッチング法及び（３）のフォトリソグラフィーにおいては、いずれもプロセスが煩雑であったり、コストが高くなるなどの問題があった。
【０００３】
【発明が解決しようとする課題】
本発明は、このような状況下で、ガラス基材表面の任意の位置に、高さや幅が制御された凸形状を効率よく形成させる工業的に有利なガラス基材の微細加工方法、及びガラス基材表面に凸形状を形成させる微細加工方法に好適に使用し得る微細加工用ガラス基材を提供することを目的とするものである。
【０００４】
【課題を解決するための手段】
本発明者らは、前記目的を達成するために鋭意研究を重ねた結果、ガラス基材の表面及びその近傍に、使用するエッチング液に対するエッチングレートが他の部分と異なる領域を設け、このガラス基材を化学的エッチング処理することにより、ガラス基材表面に凸を効率よく形成させ得ることを見出した。
【０００５】
また、ガラス基材の表面及びその近傍に、前記エッチングレートが他の部分と異なる領域を有し、化学的エッチング処理によりガラス基材表面に凸を形成し得る能力を有するガラス基材、特にＳｉＯ2とＡｌ2Ｏ3を含み、ＳｉＯ2含有量とＡｌ2Ｏ3含有量との差、すなわち（ＳｉＯ2含有量−Ａｌ2Ｏ3含有量）が特定の範囲にあり、かつ酸性液で化学的エッチング処理し得るガラス基材が、微細加工用ガラス基材として好適であることを見出した。本発明は、かかる知見に基づいて完成したものである。
【０００６】
すなわち本発明は、（１）ガラス基材の表面及びその近傍に、使用するエッチング液に対するエッチングレートが他の部分と異なる圧縮応力部を、該ガラス基材表面の所定個所に１個又は複数個の圧子を押し当てて外力を印加して物理的に形成し、次いでこのガラス基材を当該エッチング液により化学的エッチング処理して、ガラス基材表面に凹凸を形成させることを特徴とするガラス基材の微細加工方法であって、該ガラス基材を構成する母材が、ＳｉＯ 2 及び１モル％以上のＡｌ 2 Ｏ 3 を含むことを特徴とするガラス基材の微細加工方法、（２）前記ガラス基材におけるＳｉＯ 2 含有量とＡｌ 2 Ｏ 3 含有量との差（ＳｉＯ 2 含有量−Ａｌ 2 Ｏ 3 含有量）が４０〜６７モル％である上記（１）項記載のガラス基材の微細加工方法、（３）前記ＳｉＯ 2 含有量−Ａｌ 2 Ｏ 3 含有量が４７〜５７モル％である上記（２）項記載のガラス基材の微細加工方法、（４）前記ガラス基材が、さらにアルカリ土類金属酸化物３〜１６モル％を含む上記（１）ないし（３）項のいずれかに記載のガラス基材の微細加工方法、（５）前記アルカリ土類金属酸化物の含有量が３〜１１モル％である上記（４）項記載のガラス基材の微細加工方法、（６）前記ガラス基材表面の所定個所 に圧子を等間隔で押し当てながら、該圧子とガラス基材とを相対的に移動させて外力を印加し、化学的エッチング処理によりガラス基材表面に凸形状をストライプ状に形成させる上記（１）ないし（５）項のいずれかに記載のガラス基材の微細加工方法、（７）前記ガラス基材表面の所定個所に、圧子として所定のピッチを有する凸パターンを刻んだ金型を用い、該凸パターンを押し当てて外力を印加しながら移動させる上記（１）ないし（５）項のいずれかに記載のガラス基材の微細加工方法、（８）圧縮応力部がガラス基材表面から、深さ０．０２〜２０μｍにわたる領域に存在する上記（１）ないし（７）のいずれかに記載のガラス基材の微細加工方法、（９）圧縮応力部を形成後、化学的エッチング処理を施す前に、外力印加部の中央近傍に生じた凹みを研磨により除去する上記（１）ないし（８）項のいずれかに記載のガラス基材の微細加工方法、（１０）エッチング液のｐＨが５以下である上記（１）ないし（９）項のいずれかに記載のガラス基材の微細加工方法、（１１）エッチング液がフッ素イオンを含む上記（１０）項記載のガラス基材の微細加工方法、（１２）エッチング液が硫酸、塩酸、硝酸、リン酸、スルファミン酸、シュウ酸、酒石酸、リンゴ酸及びクエン酸の中から選ばれる少なくとも一種を添加したものである上記（１０）又は（１１）項記載のガラス基材の微細加工方法、及び（１３）エッチング液による化学的エッチング処理後、この化学的エッチング処理により形成したガラス表面の変質層をアルカリ性水溶液で洗浄処理する上記（１０）ないし（１２）項のいずれかに記載のガラス基材の微細加工方法、を提供するものである。
【０００７】
まず、本発明のガラス基材の微細加工方法について説明する。本発明のガラス基材の微細加工方法は、ガラス基材の表面及びその近傍に、使用するエッチング液に対するエッチングレートが他の部分と異なる圧縮応力部を、該ガラス基材表面の所定個所に１個又は複数個の圧子を押し当てて外力を印加して物理的に形成し、次いでこのガラス基材を当該エッチング液により化学的エッチング処理して、ガラス基材表面に凸を形成させる方法である。ここで、エッチングレートが他の部分と異なる領域を設けるには、ガラス基材の表面とその近傍に圧縮応力部を形成する。
【０００８】
本発明者らは、前記圧縮応力部は、他の部分に比べて化学的エッチング速度が遅いことを見出した。この理由については必ずしも明確ではないが、例えば外部より圧力を印加し、ガラス基材の表面近傍に圧縮応力部を物理的に形成した場合には、該圧縮応力部は他の部分に比べて密度が大きくなることも一つの要因と考えられる。本発明の微細加工方法は、このような化学的エッチング速度の差を利用して、ガラス基材表面に凸形状を形成させる技術である。
【０００９】
ガラス基材の表面及びその近傍に圧縮応力部を形成させる方法としては、物理的方法と化学的方法とがある。物理的方法により、圧縮応力部を形成し、化学的エッチング処理してガラス基材に微細加工を施すには、例えばガラス基材表面の所定個所に外力を印加して、該表面とその近傍に圧縮応力部を物理的に形成し、化学的エッチング処理により凸形状をガラス基材表面に形成させる方法を好ましく用いることができる。
【００１０】
また、化学的方法により、圧縮応力部を形成し、化学的エッチング処理して、ガラス基材に微細加工を施すには、例えばガラス基材表面に、所定形状のマスクパターンを設け、該ガラス基材を化学強化処理し、その表面とその近傍に圧縮応力部を化学的に形成したのち、マスクパターンを除去し、化学的エッチング処理により凸形状をガラス基材表面に形成させる方法を好ましく用いることができる。
【００１１】
本発明のガラス基材の微細加工方法においては、ガラス基材として、ＳｉＯ2及び１モル％以上のＡｌ2Ｏ3を含み、かつＳｉＯ2含有量−Ａｌ2Ｏ3含有量が４０〜６７モル％であるガラス母材を用い、酸性液で化学的エッチング処理することが、ガラス基材表面に凸形状を効果的に形成させる点から有利である。
【００１２】
前記ガラス母材は、多成分系ガラスであって、ＳｉＯ2を主成分とし、かつ１モル％以上のＡｌ2Ｏ3が含有されており、このＡｌ2Ｏ3は酸性溶液に溶出しやすいため、エッチング処理が促進される。ガラスに含まれるＳｉＯ2とＡｌ2Ｏ3のモル濃度の差（ＳｉＯ2−Ａｌ2Ｏ3）が小さくなる、すなわち耐酸性の弱いＡｌ2Ｏ3が相対的に多くなるに伴い、溶出が促進されエッチングレートが飛躍的に大きくなる。その一方で、Ａｌ2Ｏ3は酸以外の薬品に対しては耐食性に優れている。
【００１３】
ガラス表面に圧子を用いて部分的に応力印加すると、その表面とその近傍には圧縮応力部が形成される（図１参照）。この圧縮応力部では、その他の通常部とは異なる化学的性質を示し、前記のＡｌ2Ｏ3を含有するガラスの表面に圧縮応力部を形成させると、エッチング処理を行った際にエッチングレート差が生じる。そのメカニズムは完全には明らかになっていないが、応力印加で形成した圧縮応力部ではガラスの結晶状態の変化、相変態、密度上昇等が生じ、緻密化したシロキサンネットワークがその他の成分の溶出を妨げる一方、その他の通常部ではＡｌ2Ｏ3が酸性エッチング液によリ選択的にエッチングされると考えられる。
【００１４】
図５は、ガラス成分と１μｍエッチングした際に形成される突起の高さ（突起形成効率）との関係を示すグラフである。前記の応力印加によって圧縮応力部を形成させたガラスをエッチング処理すると、この図５に示すように、ＳｉＯ2−Ａｌ2Ｏ3が小さくなる、すなわちＡｌ2Ｏ3が相対的に多くなるに伴い、圧縮応力部には背の高い突起が形成される。これはＡｌ2Ｏ3が相対的に増えるに従い、通常部のエッチングレートは大きくなる一方で、圧縮応力部のエッチングレートの変化量は低く抑えられるためエッチングレート差が大きくなり、その結果背の高い凸型形状の突起が形成される。
【００１５】
しかし、図５で示されるように、ガラスに含まれるＳｉＯ2とＡｌ2Ｏ3のモル濃度の差（ＳｉＯ2−Ａｌ2Ｏ3）がある値より小さくなると凸形状の突起の高さが再び低くなり始める。以上から、本発明の微細加工方法をガラス基材に用いることのできる多成分系ガラスとして、モル％で表示したガラス中のＳｉＯ2含有量とＡｌ2Ｏ3含有量の差（ＳｉＯ2含有量−Ａｌ2Ｏ3含有量）は、ガラスの耐水性を劣化させないようにする観点から４０モル％以上とするのが好ましく、さらにエッチング量に対して効率よく高い突起が得られるガラスとする観点から４７モル％以上とするのが好ましい。一方、Ａｌ2Ｏ3のガラス中への多量の添加によって生じる耐酸性の低下を抑制し、かつガラスの溶融温度の上昇を抑制し、比較的低い溶融温度で組成均質性の高いガラスとする観点から、ＳｉＯ2含有量−Ａｌ 2Ｏ3含有量の値は６７モル％以下とするのが好ましく、さらにエッチング量に対して効率よく高い突起が得られるガラスとする観点から５７モル％以下とするのが好ましい。
【００１６】
また、ＳｉＯ2含有量は４０モル％以上が好ましく、一方Ａｌ2Ｏ3含有量は１モル％以上が肝要であるが、上限としては１５モル％以下が好ましい。ＳｉＯ2は、本発明で用いるガラスの基本的構成成分であり、化学的耐久性の付与及び突起形成性の点から、４０モル％以上が好ましい。また、Ａｌ2Ｏ3は、ガラスの溶解性を確保し、均質なガラスとし、これにより突起形成の場所によるばらつきを小さくし得る点から、１５モル％以下が好ましい。
【００１７】
本発明の微細加工方法において、ガラス基材に用いられるガラスの種類としては、ＳｉＯ2及びＡｌ2Ｏ3を前述したような割合で含み、例えば、応力印加などによって、エッチングレートが低下した圧縮応力部を容易に形成でき、その後エッチング処理することによって突起が形成できるガラスであればよく、特に制限はない。このようなガラス基材の種類の例を挙げれば、アルミノケイ酸塩ガラス、アルミノホウケイ酸塩ガラス、ホウケイ酸塩ガラス等から選択できる。また、ガラス基材の形状も用途に応じたものでよい。
【００１８】
前記のホウケイ酸塩ガラス等に含まれているＢ2Ｏ3は、ガラス中でＡｌ2Ｏ3と同様の作用を示すと考えられ、ガラス基材に含まれていても本発明の実施には差し支えない。アルカリ土類金属酸化物（ＭｇＯ，ＣａＯ，ＳｒＯ及びＢａＯ）はガラス溶融時の溶解性を高める成分である。またこれらの金属酸化物が含まれることでエッチングレートが高くなることから、特にＳｉＯ2含有量−Ａｌ2Ｏ3含有量が４７〜５７モル％の範囲内のガラス基材には、アルカリ土類金属酸化物（ＭｇＯ，ＣａＯ，ＳｒＯ及びＢａＯ）を一種以上含有し、その合計のモル濃度は３モル％以上であることが好ましい。またガラスの耐失透性の低下を抑えるため、合計のモル濃度は１６モル％以下、特に化学的耐久性の点から１１モル％以下であることが好ましい。
【００１９】
また、このガラス基材に用いるこのできる多成分系ガラスには、所望によりアルカリ金属酸化物（ＬｉＯ2及びＮａ2Ｏ）を０〜２２モル％程度含有させることができる。これらのアルカリ金属酸化物はガラス溶融時の溶解性を高める成分である。本発明によるガラス表面に突起を形成させる方法は、アルカリ金属酸化物をほとんど含まない無アルカリガラスにも適用可能であり、また２０モル％近く含んでいても突起形成が可能である。しかし、ガラスにアルカリ金属酸化物が多く含まれると化学的耐久性が悪化する恐れがあるため、２２モル％以下とすることが好ましい。なお、これらのアルカリ金属酸化物をガラス中に含有させることにより、イオン交換による化学強化が可能となり、後述の化学強化処理により、ガラス基材の表面とその近傍に圧縮応力部を形成することができる。
【００２０】
さらに、光学部材向けガラスとして好適に用いることができるよう、屈折率や着色を制御するためにＴｉＯ2，ＺｎＯ，Ｌａ2Ｏ3等の金属酸化物を一種以上含有することもできる。これらの他にも、本発明が要求している諸特性を損なわない範囲で他の金属酸化物等を適宜含有していてもよい。次に、本発明のガラス基材の微細加工方法において、ガラス基材表面の所定個所に外力を印加し、該表面及びその近傍に圧縮応力部を物理的に形成させるには、ガラス基材表面の所定個所に１個又は複数個の圧子を押し当てて外力を印加すればよい。この際、ガラス基材の所定個所に該圧子を等間隔で押し当て、圧縮応力部を設け、化学的エッチング処理により、ガラス基材表面に凸形状を規則的に形成させることができる。圧子の形状としては特に制限はなく、例えば複数個の圧子を押し付ける場合、華道用具の剣山型圧子などを用いることができる。なお、ここで圧子は、ガラス基材表面に大きな外力を容易かつ効率よく印加するために、その先端が鋭利な形状のものが好適に用いられる。
【００２１】
また、ガラス基材表面の所定個所に圧子を押し当てながら、該圧子とガラス基材とを相対的に移動させ、化学的エッチング処理により、凸形状をガラス基材表面にストライプ状に形成させることができる。この際、圧子としてカッターナイフや算盤珠のような回転自在な部材を用い、ガラス基材表面に押し当てながら移動させる方法などを行うことができる。また、遊離砥粒を圧縮空気でガラス基材表面に高速で吹き付け、遊離砥粒がガラス表面に衝突した個所に圧縮応力部を形成することができる。
【００２２】
さらに、応力の印加に複数の圧子や転写したい形状を刻んだ金型を用いることで、複雑な形状の圧縮応力部を形成することができるので好ましい。例えば、圧子として、所定のピッチ、例えば１〜１０００μｍ程度のピッチを有する凸パターンを刻んだ金型を用い、ガラス基材表面に該凸パターンを押し当てて外力を印加しながら移動させれば、金型と同じピッチで圧縮応力部を形成することができる。上述の応力の印加に用いられる圧子の材質は金属、金属酸化物、金属窒化物、ダイヤモンドまたはこれらの複合物から選ぶことができる。
【００２３】
加えて、走査型プローブ顕微鏡（ＳＰＭ）のプローブは、ＳＰＭを操作してガラス基材の任意の位置に圧縮応力部を形成できるので好ましい。このようにして、外力の印加によりガラス基材の表面及びその近傍に物理的に形成された圧縮応力部は、ガラス基材表面から、深さ方向０．０２〜２０μｍにわたる領域に存在する、即ち圧縮応力部の深さは０．０２〜２０μｍの範囲にあるのが好ましい。この深さが０．０２μｍ未満では突起はほとんど形成されず、また２０μｍを超えるとガラス基材にクラックが発生しやすくなる。さらに、この圧縮応力部の幅としては特に制限はないが、ガラス基材表面において１〜５００μｍ程度が好ましい。
【００２４】
本発明においてガラス表面に付与される圧縮応力部は、深くかつ大きな圧縮応力が形成されている場合は、偏光顕微鏡法により確認することができる場合があるが、通常このような簡便な測定により明瞭に確認できない場合が多い。
【００２５】
ガラス基材表面にカッターナイフの刃を手作業で押し付け掃引する方法でも圧縮応力部を形成することが十分可能であるが、圧子を押し付ける応力の強さは、形成する圧縮応力部の深さに影響するため制御することがより望ましい。例えば前記ＳＰＭの他にスクラッチ試験機やビッカース硬度計などが利用できる。この他にも圧子に超音波を印加しながら行うこともできる。ガラス基材表面が水でぬれた状態で外力を印加すると、局部的に大きな応力がガラス表面にかかり微小な傷が生じた場合に、そこから水が基材内部に入り込みクラックを成長させるので、圧子による外力の印加は乾燥空気下で行う方が好ましい。
【００２６】
圧子を押し当てて圧縮応力部を形成すると、後述の図１に示すような凹み部が形成されるため、この凹み部を残存させた状態でエッチング処理した場合は、突起の断面形状は、該図１に示すように、略Ｖ字状またはカルデラ状になる場合がある。したがって、必要に応じて外力印加部の中央近傍に生じた凹み部を表面処理により除去した後に、エッチング処理を施すようにしても良い。表面処理としては、ガラス基材表面に傷等が付かないようにする必要があり、したがってガラス基材の硬度と同等またはそれ以下の硬度を有する遊離砥粒を使用して研磨するのが好ましく、また、遊離砥粒は球形であるのが好ましく、例えばコロイダルシリカを使用することができる。
【００２７】
本発明の微細加工方法においては、ガラス基材として、前述のＳｉＯ2とＡｌ2Ｏ3を必須成分とするガラス母材を用いる場合には、エッチング液として酸性液が使用される。この酸性液は、ガラス基材からＳｉＯ2以外の成分を選択的に溶出することが必要であり、さらに前記エッチング液によるエッチング処理で圧縮応力部とそれ以外の通常部とで前記の選択的溶出量が異なることが求められる。
【００２８】
そのため、エッチング液はｐＨ５以下の水溶液であることが好ましい。エッチング処理によりガラス基材中から選択的に溶出されるのはＡｌ2Ｏ3などの耐酸性の低い成分であることから、エッチング液は酸性寄りであることが求められる。このようなエッチング液として、フッ素イオンを含有する酸性の水溶液、例えばフッ化水素酸水溶液を用いることができる。
【００２９】
また、この酸性のエッチング液には、硫酸、塩酸、硝酸、リン酸、スルファミン酸、シュウ酸、酒石酸、リンゴ酸及びクエン酸の中から選ばれる少なくとも一種が添加されたものを使用することができる。このように、酸性エッチング液でエッチング処理を行うと、Ａｌ2Ｏ3などガラスを構成する成分の一部がエッチング液に溶出し、ガラス基材表面にＳｉＯ2骨格が残った変質層が形成される。そこで前記エッチング液でのエッチング処理の後、ｐＨ７以上のアルカリ性水溶液でさらに洗浄処理することができる。これにより、前記変質層を除去することができる。
【００３０】
こうして、ガラス基材の表面に部分的に外力を印加し、次いで化学的にエッチング処理することにより、前記ガラス基材表面に凸型形状の突起を形成することができる。物理条件により、突起の位置や高さを制御できるため、光学部品に用いるガラス基材の表面微細加工技術として利用することができる。
【００３１】
図１は、本発明のガラス基材の微細加工方法の一例を示す工程図であって、ガラス基材表面に点状凸部を形成させる場合である。図１（ａ）は、ガラス基材１に圧子２により外力を印加（Ａ）する状態を示し、（ｂ）は、ガラス基材１に圧子を押し当てて外力を印加した際に生じる凹み面３及び圧縮応力付与部４を示す。（ｃ）は前記（ｂ）工程で得られたガラス基材に化学的エッチング処理を施し、圧縮応力付与部４を含む凸形状５が形成された状態を示す。なお、６は化学的エッチング処理により生成した変質層であり、７は該変質層の表面である。（ｄ）は、前記（ｃ）工程で得られたガラス基材１にアルカリ水溶液による洗浄処理を施し、変質層６を除去した状態を示す。なお、前記（ｂ）工程と（ｃ）工程の間に、所望により、凹み面３を研磨処理して、凹みを除去する工程を設けることができる。
【００３２】
図２は、本発明のガラス基材の微細加工方法の異なる例を示す工程図であって、ガラス基材１表面にストライプ状凸部を形成させる場合である。図２（ａ）は、ガラス基材１に圧子８を押し当て、かつ掃引しながら外力を印加（Ｂ）し、圧縮応力付与部９を形成した状態を示す。（ｂ）は、前記（ａ）工程で得られたガラス基材１に化学的エッチング処理を施し、圧縮応力付与部９を含むストライプ状凸形状１０が形成された状態を示す。なお、１１は化学的エッチング処理により生成した変質層を示す。（ｃ）は、前記（ｂ）工程で得られたガラス基材１にアルカリ水溶液による洗浄処理を施し、変質層１１を除去した状態を示す。
【００３３】
図３は、本発明のガラス基材の微細加工方法における凸部形成のメカニズムを示す説明図である。図３（ａ）で示すように、ガラス基材１４の表面近傍に形成された圧縮応力付与部１３は、圧子による外力の印加条件によりその形状、例えば深さ方向、水平方向の寸法などを調整することができる。この図では、ガラス表面から最大深さＨを有するものを含んで図示されている。また、（ｂ）で示されるように、化学的エッチング処理により、圧縮応力付与部１３は深さ方向に浅くエッチングされ（エッチングレートがこの部分では、相対的に小さい。）、圧縮応力付与部１３以外の部分１２は、圧縮応力付与部１３より深くガラスがエッチングされる。これにより、圧縮応力付与部１３に対応した凹凸パターンが形成される。なお、１３′は凸部、１２′は平坦部である。
【００３４】
変質層１５は、ガラス中のアルカリ成分（Ｒ2Ｏ）やアルカリ土類成分（Ｒ′Ｏ）が選択的に溶出し、その結果微細な空隙を有すると考えられるシリカリッチ成分からなるので、機械的性質に劣る。したがって、この変質層は除去することが好ましい。（ｃ）は、前記変質層１５をアルカリ性水溶液で溶解除去したあとの状態を示す。このようにして、前記（ａ）の圧縮応力付与部１３の形状に対応して凹凸が形成される。なお、１３″は凸部、１２″は平坦部である。
【００３５】
本発明のガラス基材の微細加工方法においては、圧縮応力付与を、点状、線状に行うことにより、ドット配列凸形状、ストライプパターン状凸形状をガラス基材表面に形成させることができる。圧縮応力付与点の間隔を傾斜的に変えることなどにより、種々の規則的に配列された凸形状を、フォトリソグラフィーの手法を用いることなく形成することができる。
【００３６】
本発明の微細加工用ガラス基材は、ガラス基材の表面近傍に、使用するエッチング液に対するエッチングレートが他の部分と異なる領域を有し、かつ当該エッチング液による化学的エッチング処理により、ガラス基材表面に凸を形成し得る能力を有するものである。具体的には、ガラス基材の表面及びその近傍に、使用するエッチング液に対するエッチングレートが他の部分と異なる圧縮応力部を有し、かつ当該エッチング液による化学的エッチング処理により、ガラス基材表面に凸形状を形成し得る能力を有するものを挙げることができる。この微細加工用ガラス基材においては、ガラス基材を構成するガラス母材として、前述のガラス基材の微細加工方法において説明したものと同じものを好ましく用いることができる。
【００３７】
また、ガラス基材の表面及びその近傍に圧縮応力部を有し、該ガラス基材表面を最初に１μｍ化学的エッチング処理した際に、高さ０．０６〜１μｍの凸部を形成し得るものが好ましい。さらに、ガラス基材の表面とその近傍に規則的な圧縮応力部を有し、化学的エッチング処理により、ガラス基材表面に規則的な凸形状パターンを形成し得るものが好適である。本発明はまた、前述の本発明のガラス基材の微細加工方法により、表面に凸を形成してなる微細加工ガラス製品をも提供する。
【００３８】
図４は、本発明の微細加工ガラス製品の異なる例を示す平面図（イ）及び正面図（ロ）である。図４において、（ａ）は凸部が規則的に点状配列された例を示し、（ｂ）は凸部がストライプ状に配列された例を示し、（ｃ）は凸部が傾斜的かつ規則的に点状配列された例を示す。このような微細加工ガラス製品は、例えばマイクロレンズ、マイクロプリズム、回折格子などの微小光学素子などとして好適である。
【００３９】
【実施例】
次に、本発明を実施例によりさらに詳細に説明するが、本発明は、これらの例によってなんら限定されるものではない。なお、第１表に、実施例及び比較例で用いたガラス基材の組成を示す。
【００４０】
【表１】

Figure 0003953760
【００４１】
実施例１
先端が曲率半径５μｍの球面形状であるダイヤモンド圧子を、レスカ製スクラッチ試験機ＣＳＲ−０２型を用いて組成１のガラス基材表面に押し当て直線状に掃引し、これにより凹み部を有する圧縮応力部を形成した。このガラス基材をｐＨ２．８のフッ酸水溶液に浸漬し、さらにｐＨ１２のアルカリ性水溶液に浸漬することにより１３μｍエッチングし、実施例１の試験片を作製した。この試験片の表面形状を表面粗さ計（Ｔｅｎｃｏｒ社製「Ａｌｐｈａ−ｓｔｅｐ５００型」）で観察したところ、圧縮応力部を形成した部分に沿って高さ６．８μｍで断面が山形の尾根状突起が形成されていた。
【００４２】
実施例２
ガラス基材に組成３を用い、実施例１と同様の方法で圧縮応力部を形成し、１．０μｍエッチングして実施例２の試験片を作製した。この試験片の表面形状を表面粗さ計で観察したところ、圧縮応力部を形成した部分に沿って高さ０．２５μｍで断面が山形の尾根状突起が形成されていた。
【００４３】
実施例３
ガラス基材に組成４を用い、実施例１と同様の方法で圧縮応力部を形成し、３．５μｍエッチングして実施例３の試験片を作製した。この試験片の表面形状を表面粗さ計で観察したところ、圧縮応力部を形成した部分に沿って高さ０．５４μｍで断面が山形の尾根状突起が形成されていた。
【００４４】
実施例４
ガラス基材に組成５を用い、実施例１と同様の方法で圧縮応力部を形成し、３．０μｍエッチングして実施例４の試験片を作製した。この試験片の表面形状を表面粗さ計で観察したところ、圧縮応力部を形成した部分に沿って高さ１．１μｍで断面が山形の尾根状突起が形成されていた。
【００４５】
実施例５
ガラス基材に組成６を用い、実施例１と同様の方法で圧縮応力部を形成し、０．２６μｍエッチングして実施例５の試験片を作製した。この試験片の表面形状を表面粗さ計で観察したところ、圧縮応力部を形成した部分に沿って高さ０．１４μｍで断面が山形の尾根状突起が形成されていた。
【００４６】
実施例６
先端の刃厚が０．０６ｍｍの市販のカッター刃（ＮＴカッターＬ−５００用）を、組成１のガラス基材表面に押し当て手作業で直線状に１０本掃引し、これにより凹み部を有する圧縮応力部を形成した。このガラス基材をフッ酸水溶液に浸漬し、さらにｐＨ１２のアルカリ性水溶液に浸漬することにより、２．５μｍエッチングし、実施例６の試験片を作製した。この試験片の表面形状を表面粗さ計で観察したところ、圧縮応力部を形成した部分に沿って幅６０μｍ、高さ１．２μｍで断面が台形の尾根状突起が１０本形成されていた。手作業で圧縮応力部を形成したにもかかわらず、どの突起も幅、高さ、形状ともに揃っていた。
【００４７】
実施例７
実施例６と同じカッター刃を、組成１のガラス基材に押し当て直線状に１０本掃引し、これにより凹み部を有する圧縮応力部を形成した。この際、ガラス基材は位置をＸＹ方向に１０μｍ単位で制御可能な試料台に載せており、直線状の圧縮応力部を１２０μｍピッチで形成させた。このガラス基材をｐＨ１．４のフッ酸と硫酸の混合水溶液に浸漬し、さらにｐＨ１２のアルカリ性水溶液に浸漬することにより２．５μｍエッチングし、実施例７の試験片を作製した。この試験片の表面形状を表面粗さ計で観察したところ、幅６０μｍ、高さ１．３μｍで断面が台形の尾根状突起が１２０μｍピッチで形成されていた。
【００４８】
実施例８
実施例６と同じカッター刃を、組成１のガラス基材に押し当て直線状に１０本掃引し、これにより凹み部を有する圧縮応力部を形成した。この際、ガラス基材は位置をＸＹ方向に１０μｍ単位で制御可能な試料台に載せており、直線状の圧縮応力部を１２０μｍピッチで形成させた。そしてこの後、コロイダルシリカが混入したスラリーを使用して５０ｎｍ研磨し、前記凹み部を除去した。次に、このガラス基材をフッ酸水溶液に浸漬し、さらにｐＨ１２のアルカリ性水溶液に浸漬することにより２．５μｍエッチングし、実施例８の試験片を作製した。この試験片の表面形状を表面粗さ計で観察したところ、幅６０μｍ、高さ１．２μｍで断面が台形の尾根状突起が１２０μｍピッチで形成されていた。実施例７と比較して、断面が台形状の突起の頂点部を平坦にすることができ、一方研磨によって突起の幅や高さが変化することはなかった。
【００４９】
実施例９
ピッチ２５μｍ、深さ１３μｍのＶ字溝が刻まれた１０ｍｍ角のシリコン製金型を、組成１のガラス基材にエッジを立てて押し当て溝の方向に掃引し、これにより圧縮応力部を形成した。このガラス基材をフッ酸水溶液に浸漬することにより２．５μｍエッチングし、実施例９の試験片を作製した。この試験片の表面形状をＡＦＭ（原子間力顕微鏡）で観察したところ、圧縮応力部を形成した部分に沿って幅１０μｍ、高さ１．２μｍで断面が山形の尾根状突起がピッチ２５μｍを保ったまま形成されていた。
【００５０】
実施例１０
バネ定数４６Ｎ／ｍで先端が曲率半径１０ｎｍの球面形状であるダイヤモンドコートシリコン単結晶製ＡＦＭ用プローブを、ＡＦＭ装置（Ｔｈｅｒｍｏ Ｍｉｃｒｏｓｃｏｐｅｓ社製「Ｍ５型」）を用いて組成１のガラス基材表面に押し当て直線状に５本掃引し、これにより凹み部を有する圧縮応力部を１μｍピッチで形成した。このガラス基材をフッ酸水溶液に浸漬することにより０．５μｍエッチングし、実施例１０の試験片を作製した。この試験片の表面形状をＡＦＭで観察したところ、幅１μｍ、高さ０．１６μｍで断面が山形の尾根状突起が１μｍピッチで形成されていた。
【００５１】
実施例１１
粒径５μｍのアルミナ研磨剤を１７ｖｏｌ％含んだスラリーを、０．０５ＭＰａの圧搾空気で９０×２．０ｍｍのノズルから霧状に吹き出しながら、ノズルを２５ｍｍ／ｓの速さで組成１のガラス基材表面を走査して吹き付け、これにより凹み部を有する多数の圧縮応力部を形成した。そしてこの後コロイダルシリカが混入したスラリーを使用して６０ｎｍ研磨し、前記凹み部を除去した。このガラス基材をフッ酸水溶液に浸漬し、さらにｐＨ１２のアルカリ性水溶液に浸漬することにより０．２４μｍエッチングし、実施例１１の試験片を作製した。そして、該試験片の表面形状をＡＦＭで観察したところ、試験片の表面には１０μｍ角当たり８４個の微小凸部が形成され、その形状は、底面が直径０．５７μｍの略円形の山形形状であり、突起高さは０．１３μｍであった。
【００５２】
実施例１２
実施例６と同じカッター刃を、組成１のガラス基材表面に押し当て手作業で直線状に１０本掃引し、これにより凹み部を有する圧縮応力部を形成した。このガラス基材をフッ酸と硫酸の混合水溶液（ｐＨ１．４）に浸漬することにより１．０μｍエッチングし、実施例１２の試験片を作製した。この試験片の表面形状を表面粗さ計で観察したところ、圧縮応力部を形成した部分に沿って幅６０μｍ、高さ０．５５μｍで断面が台形の尾根状突起が１０本形成されていた。
【００５３】
実施例１３
ガラス基材に組成７を用い、実施例１２と同様の方法で圧縮応力部を形成し、０．９５μｍエッチングして実施例１３の試験片を作製した。この試験片の表面形状を表面粗さ計で観察したところ、圧縮応力部を形成した部分に沿って高さ０．７１μｍで断面が山形の尾根状突起が形成されていた。
【００５４】
実施例１４
ガラス基材に組成８を用い、実施例１２と同様の方法で圧縮応力部を形成し、１．１μｍエッチングして実施例１４の試験片を作製した。この試験片の表面形状を表面粗さ計で観察したところ、圧縮応力部を形成した部分に沿って高さ０．０２μｍで断面が山形の尾根状突起が形成されていた。
【００５５】
実施例１５
ガラス基材に組成９を用い、実施例１２と同様の方法で圧縮応力部を形成し、０．２０μｍエッチングして実施例１５の試験片を作製した。この試験片の表面形状を表面粗さ計で観察したところ、圧縮応力部を形成した部分に沿って高さ０．１０μｍで断面が山形の尾根状突起が形成されていた。
【００５６】
比較例１
ガラス基材に組成２を用い、実施例１と同様の方法で圧縮応力部を形成し、２．７μｍエッチングして比較例１の試験片を作製した。この試験片の表面形状を表面粗さ計で観察したが、圧縮応力部を形成した部分には突起が形成されていなかった。ガラスに含まれるＡｌ2Ｏ3が少ないため、圧縮応力部での選択的溶出量の変化がほとんど起こらなかったと考えられる。
【００５７】
比較例２
組成１のガラス基材に実施例６と同様の方法で圧縮応力部を形成した。このガラス基材をｐＨ５．６のフッ酸とフッ化アンモニウムの混合水溶液に浸漬することにより１．０μｍエッチングし、比較例２の試験片を作製した。この試験片の表面形状を表面粗さ計で観察したが、圧縮応力部を形成した部分には突起が形成されていなかった。エッチング処理に用いたエッチング液が中性であり、耐酸性の低いＡｌ2Ｏ3の選択的溶出が起こらなかったと考えられる。
【００５８】
比較例３
ピッチ２５μｍ、深さ１３μｍのＶ字溝が刻まれた１０ｍｍ角のポリカーボネート製金型を、組成１のガラス基材にエッジを立てて押し当て溝の方向に掃引した。このガラス基材をフッ酸水溶液に浸漬することにより２．５μｍエッチングし、比較例３の試験片を作製した。この試験片の表面形状をＡＦＭで観察したが、突起が形成されていなかった。ポリカーボネート樹脂はガラスと比較して柔らかいため、圧縮応力部を形成するのに十分な応力を印加することができないと考えられる。以上の結果を第２表にまとめて示す。
【００５９】
【表２】
Figure 0003953760
【００６０】
【表３】
Figure 0003953760
【００６１】
【表４】
Figure 0003953760
【００６２】
また、図５に、ＳｉＯ2含有量−Ａｌ2Ｏ3含有量（モル％）と突起形成効率との関係をグラフで示し、図６に、実施例１及び比較例１におけるエッチング量と突起高さとの関係をグラフで示す。また図７に、突起形成効率に及ぼすアルカリ土類金属酸化物の合計含有量の影響をプロット図で示す。なお、突起形成効率は、１μｍエッチングした際に形成された突起の高さ（μｍ）で表した値である。
【００６３】
本発明の微細加工方法の圧縮応力部を形成する方法は、たとえばレーザビームスプリッター用の透過型回折格子素子の場合は格子周波数（ピッチ）が９〜１４ｎｍ（７０〜１１０本／ｍｍ）の凹凸が要求され、反射型回折格子素子の場合は格子周波数（ピッチ）が０．８〜３．３ｎｍ（３００〜１２００本／ｍｍ）の凹凸が要求され、このような光学素子をフォトリソグラフ法のような高価な方法を用いることなく安価に製作するのに好ましい方法である。
【００６４】
【発明の効果】
本発明のガラス基材の微細加工方法によれば、ガラス基材の表面及びその近傍にエッチングレートが他の部分と異なる領域を設け、化学的エッチング処理することにより、ガラス基材表面の任意の位置に、高さや幅が制御された凸形状を、安価にかつ効率よく形成させることができる。この方法により作製された微細加工ガラス製品は、例えばマイクロレンズ、マイクロプリズム、回折格子などの微小光学素子などに好適に用いられる。
【図面の簡単な説明】
【００６５】
【図１】本発明のガラス基材の微細加工方法の一例を示す工程図である。
【図２】本発明のガラス基材の微細加工方法の異なる例を示す工程図である。
【図３】本発明のガラス基材の微細加工方法における凸部形成のメカニズムを示す説明図である。
【図４】本発明の微細加工ガラス製品の異なる例を示す平面図及び正面図である。
【図５】実施例において、ＳｉＯ2含有量−Ａｌ2Ｏ3含有量（モル％）と突起形成効率との関係を示すグラフである。
【図６】実施例１及び比較例１におけるエッチング量と突起高さとの関係を示すグラフである。
【図７】実施例及び比較例において、突起形成効率に及ぼすアルカリ土類金属酸化物の合計含有量の影響を示すプロット図である。
【符号の説明】
【００６６】
１ ガラス基材
２ 圧子
３ 凹み面
４ 圧縮応力付与部
５ 凸形状
６ 変質層
７ 変質層表面
８ 圧子
９ 圧縮応力付与部
１０ ストライプ状凸形状
１１ 変質層
１２ 圧縮応力付与部以外の部分
１２′ 平坦部
１２″ 平坦部
１３ 圧縮応力付与部
１３′ 凸部
１３″ 凸部
１４ ガラス基材
１５ 変質層[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a glass substrate microfabrication method, a glass substrate for microfabrication, and a microfabricated glass product. More specifically, the present invention forms a region having an etching rate different from that of the other part on the surface of the glass substrate and the vicinity thereof, and a chemical etching process using the difference in etching rate with the other part. Convex on substrate surfaceShapeMicro-processing method of glass substrate to be formed, convex shape on glass substrate surfaceShapeThe present invention relates to a glass substrate for microfabrication that can be suitably used for a micromachining method to be formed, and a microfabricated glass product obtained by the micromachining method and suitable as a micro optical element such as a diffraction grating or a microlens.
[0002]
[Prior art]
  In recent years, with the industrial technology revolution such as information technology (IT), a technology for finely processing the glass surface on the order of μm or nm has been required. For example, micro-optical elements such as microlenses, microprisms, and diffraction gratings used in various optical devices are required to have a concavo-convex pattern controlled on the order of μm. And, as a processing method for forming such a concavo-convex pattern controlled on the order of μm on the glass surface, conventionally, (1) a glass substrate is pressed against a mold via a resin layer or a sol-gel film and cured. Embossing method to transfer mold shape, (2) Method of directly dry etching glass substrate with laser beam or ion beam, etc., (3) Photoresist film provided on glass substrate surface is selectively exposed and developed Various processing methods such as a photolithography method in which a resist pattern is formed by processing and etching is performed using the resist pattern as a mask have been studied. However, the embossing method using the resin layer (1) or the sol-gel film (1) has insufficient heat resistance from the viewpoint of the material, and the etching method using the laser beam or ion beam (2) and the photo method (3). In the case of lithography, there are problems such as complicated processes and high costs.
[0003]
[Problems to be solved by the invention]
  Under such circumstances, the present invention controls the height and width at an arbitrary position on the surface of the glass substrate.ConvexIndustrially advantageous glass substrate microfabrication method for efficiently forming a shape, and glass substrate surfaceConvexAn object of the present invention is to provide a glass substrate for microfabrication that can be suitably used in a microfabrication method for forming a shape.
[0004]
[Means for Solving the Problems]
  As a result of intensive studies to achieve the above object, the inventors of the present invention provided a region on the surface of the glass substrate and in the vicinity thereof where the etching rate for the etchant used is different from that of other portions. Glass substrate surface by chemically etching the materialConvexIt was found that can be formed efficiently.
[0005]
  Further, the surface of the glass substrate has a region where the etching rate is different from that of other portions on the surface thereof, and the surface of the glass substrate by chemical etching treatment.ConvexA glass substrate having the ability to form, in particular SiO2And Al2OThreeContaining SiO2Content and Al2OThreeDifference from content, ie (SiO2Content -Al2OThreeIt has been found that a glass substrate having a (content) in a specific range and capable of being chemically etched with an acidic solution is suitable as a glass substrate for microfabrication. The present invention has been completed based on such findings.
[0006]
  That is, in the present invention, (1) the etching rate with respect to the etching solution to be used is different from that of the other portions on the surface of the glass substrate and its vicinityThe compressive stress portion is physically formed by applying an external force by pressing one or a plurality of indenters on a predetermined location on the surface of the glass substrate.Then, this glass substrate is chemically etched with the etching solution to form irregularities on the surface of the glass substrate.The base material constituting the glass substrate is SiO 2 And 1 mol% or more of Al 2 O Three (2) SiO in the glass substrate, characterized in that 2 Content and Al 2 O Three Difference from content (SiO 2 Content -Al 2 O Three The glass substrate microfabrication method according to (1) above, wherein the (content) is 40 to 67 mol%, (3) the SiO 2 Content -Al 2 O Three (4) The said glass substrate further contains 3-16 mol% of alkaline-earth metal oxides, (4) The fine processing method of the glass substrate of the said (2) description whose content is 47-57 mol% ( 1) The fine processing method of the glass substrate according to any one of (3), (5) The glass according to (4), wherein the content of the alkaline earth metal oxide is 3 to 11 mol%. (6) a predetermined portion of the glass substrate surface; While pressing the indenter at equal intervals, the indenter and the glass substrate are moved relative to each other to apply an external force, and the convex shape is formed in a stripe shape on the glass substrate surface by chemical etching treatment (1) ) To (5) the fine processing method of the glass substrate according to any one of the paragraphs, (7) using a mold in which a convex pattern having a predetermined pitch as an indenter is engraved at a predetermined position on the surface of the glass substrate, The fine processing method of the glass substrate according to any one of (1) to (5) above, wherein the convex pattern is pressed and moved while applying an external force, (8) the compressive stress portion is from the surface of the glass substrate, (9) The fine processing method of the glass substrate according to any one of (1) to (7) above, which exists in a region having a depth of 0.02 to 20 μm, and (9) chemical etching treatment is performed after forming the compressive stress portion. Before, inside the external force application part (1) The fine processing method for a glass substrate according to any one of (1) to (8) above, wherein (10) the etching solution has a pH of 5 or less. (9) The glass substrate microfabrication method according to any one of (9), (11) The glass substrate microfabrication method according to (10), wherein the etching solution contains fluorine ions, and (12) the etching solution is sulfuric acid. Fine glass substrate according to (10) or (11) above, wherein at least one selected from hydrochloric acid, nitric acid, phosphoric acid, sulfamic acid, oxalic acid, tartaric acid, malic acid and citric acid is added. (13) After the chemical etching treatment with the etching solution and (13) the above-mentioned (10), the altered layer on the glass surface formed by the chemical etching treatment is washed with an alkaline aqueous solution. (12) The fine processing method of the glass substrate according to any one of itemsIs to provide.
[0007]
  First, the fine processing method of the glass base material of this invention is demonstrated. The fine processing method of the glass substrate of the present invention has a different etching rate with respect to the etching solution used on the surface of the glass substrate and its vicinity.The compressive stress portion is physically formed by applying an external force by pressing one or a plurality of indenters on a predetermined location on the surface of the glass substrate.Then, the glass substrate surface is chemically etched with the etching solution.ConvexIs a method of forming Here, to provide a region where the etching rate is different from other parts,Compressive stress on the surface of the lath substrate and its vicinityPartFormationDo.
[0008]
  The inventors of the present invention have found that the compressive stress portion has a slower chemical etching rate than other portions. Although the reason for this is not necessarily clear, for example, when pressure is applied from the outside and a compressive stress part is physically formed near the surface of the glass substrate, the compressive stress part has a density higher than that of other parts. Is also considered to be a factorThe The present inventionThe microfabrication method uses a difference in the chemical etching rate to provide a convex shape on the glass substrate surface.ShapeIt is a technology to form.
[0009]
  There are a physical method and a chemical method as a method for forming a compressive stress portion on the surface of the glass substrate and in the vicinity thereof. In order to form a compressive stress part by a physical method and perform fine etching on a glass substrate by chemical etching treatment, for example, an external force is applied to a predetermined portion of the surface of the glass substrate, and the surface and the vicinity thereof are applied. A method in which the compressive stress portion is physically formed and a convex shape is formed on the surface of the glass substrate by chemical etching can be preferably used.
[0010]
  In addition, in order to form a compressive stress portion by a chemical method, perform chemical etching treatment, and finely process the glass substrate, for example, a mask pattern having a predetermined shape is provided on the surface of the glass substrate, and the glass substrate It is preferable to use a method in which a material is chemically strengthened and a compressive stress portion is chemically formed on the surface and in the vicinity thereof, and then a mask pattern is removed and a convex shape is formed on the surface of the glass substrate by chemical etching treatment. Can.
[0011]
BookIn the fine processing method of the glass substrate of the invention, as the glass substrate, SiO2And 1 mol% or more of Al2OThreeAnd SiO2Content -Al2OThreeUsing a glass base material with a content of 40 to 67 mol%, chemical etching treatment with an acidic solution is convex on the glass substrate surfaceShapeThis is advantageous in terms of effective formation.
[0012]
  The glass base material is multi-component glass, and SiO21 mol% or more of Al2OThreeContains this Al2OThreeSince it is easy to elute in an acidic solution, an etching process is accelerated | stimulated. SiO in glass2And Al2OThreeDifference in molar concentration (SiO2-Al2OThree) Becomes smaller, that is, Al with weak acid resistance2OThreeAs the amount increases relatively, elution is promoted and the etching rate increases dramatically. On the other hand, Al2OThreeHas excellent corrosion resistance against chemicals other than acids.
[0013]
  When a partial stress is applied to the glass surface using an indenter, a compressive stress portion is formed on the surface and in the vicinity thereof (see FIG. 1). This compressive stress part shows different chemical properties from other normal parts, and the Al2OThreeWhen a compressive stress part is formed on the surface of the glass containing, an etching rate difference is generated when etching is performed. Although the mechanism is not completely clear, changes in the crystalline state of the glass, phase transformation, density increase, etc. occur in the compressive stress part formed by applying stress, and the dense siloxane network elutes other components. On the other hand, Al in other normal parts2OThreeIs considered to be selectively etched by the acidic etchant.
[0014]
  FIG. 5 is a graph showing the relationship between the glass component and the height (projection formation efficiency) of the protrusion formed when 1 μm is etched. When the glass on which the compressive stress portion is formed by applying the stress is etched, as shown in FIG.2-Al2OThreeBecomes smaller, that is, Al2OThreeAs the number increases relatively, a tall protrusion is formed in the compressive stress portion. This is Al2OThreeAs the etching rate increases relatively, the etching rate of the normal part increases, but the change in the etching rate of the compressive stress part is kept low, so the difference in etching rate increases, and as a result, tall convex protrusions are formed. It is formed.
[0015]
  However, as shown in FIG. 5, the SiO contained in the glass.2And Al2OThreeDifference in molar concentration (SiO2-Al2OThree) When the height is smaller than a certain value, the height of the convex protrusion starts to decrease again. From the above, as a multi-component glass that can be used for the glass substrate of the microfabrication method of the present invention, SiO in glass expressed in mol%.2Content and Al2OThreeDifference in content (SiO2Content -Al2OThreeThe content is preferably 40 mol% or more from the viewpoint of preventing deterioration of the water resistance of the glass, and 47 mol% or more from the viewpoint of obtaining a glass capable of efficiently obtaining high protrusions with respect to the etching amount. It is preferable to do this. On the other hand, Al2OThreeFrom the viewpoint of suppressing the decrease in acid resistance caused by the addition of a large amount of glass into the glass and suppressing the increase in the melting temperature of the glass, and making the glass with high composition homogeneity at a relatively low melting temperature, SiO 22Content-Al 2OThreeThe value of the content is preferably 67 mol% or less, and more preferably 57 mol% or less from the viewpoint of obtaining glass capable of obtaining high protrusions efficiently with respect to the etching amount.
[0016]
  In addition, SiO2The content is preferably 40 mol% or more, while Al2OThreeThe content of 1 mol% or more is essential, but the upper limit is preferably 15 mol% or less. SiO2Is a basic component of the glass used in the present invention, and is preferably 40 mol% or more from the viewpoint of imparting chemical durability and forming protrusions. Al2OThreeIs preferably 15 mol% or less from the viewpoint of ensuring the solubility of the glass and making the glass homogeneous, thereby reducing the variation depending on the location of the protrusion formation.
[0017]
  In the microfabrication method of the present invention, the type of glass used for the glass substrate is SiO.2And Al2OThreeAs long as it is a glass that can easily form a compressive stress portion having a reduced etching rate by applying stress, etc., and then can form protrusions by etching, there is no particular limitation. . Examples of such glass substrate types can be selected from aluminosilicate glass, aluminoborosilicate glass, borosilicate glass, and the like. Further, the shape of the glass substrate may be in accordance with the application.
[0018]
  B contained in the borosilicate glass etc.2OThreeAl in the glass2OThreeEven if it is contained in the glass substrate, it does not interfere with the implementation of the present invention. Alkaline earth metal oxides (MgO, CaO, SrO and BaO) are components that increase the solubility during glass melting. In addition, since these metal oxides are included, the etching rate is increased, and in particular, SiO 22Content -Al2OThreeThe glass substrate having a content of 47 to 57 mol% contains at least one alkaline earth metal oxide (MgO, CaO, SrO and BaO), and the total molar concentration is 3 mol% or more. Preferably there is. Further, in order to suppress a decrease in the devitrification resistance of the glass, the total molar concentration is preferably 16 mol% or less, and particularly preferably 11 mol% or less from the viewpoint of chemical durability.
[0019]
  In addition, the multi-component glass that can be used for the glass substrate may include an alkali metal oxide (LiO) if desired.2And Na2O) can be contained in an amount of about 0 to 22 mol%. These alkali metal oxides are components that enhance the solubility during glass melting. The method for forming protrusions on the glass surface according to the present invention can be applied to non-alkali glass containing almost no alkali metal oxide, and protrusions can be formed even when containing nearly 20 mol%. However, if the glass contains a large amount of alkali metal oxide, the chemical durability may be deteriorated. In addition, by containing these alkali metal oxides in the glass, chemical strengthening by ion exchange becomes possible, and a compressive stress portion can be formed on the surface of the glass substrate and in the vicinity thereof by the chemical strengthening treatment described later. it can.
[0020]
  Furthermore, TiO is used to control the refractive index and coloring so that it can be suitably used as glass for optical members.2, ZnO, La2OThreeOne or more metal oxides such as these can also be contained. In addition to these, other metal oxides and the like may be appropriately contained as long as various characteristics required by the present invention are not impaired. Next, in the microfabrication method for a glass substrate according to the present invention, an external force is applied to a predetermined portion of the glass substrate surface, and a compressive stress portion is physically formed on the surface and its vicinity. The external force may be applied by pressing one or a plurality of indenters at a predetermined location. At this time, the indenter is pressed at a predetermined position on the glass substrate at equal intervals, a compressive stress portion is provided, and a convex shape can be regularly formed on the surface of the glass substrate by chemical etching. There is no restriction | limiting in particular as a shape of an indenter, For example, when pressing a several indenter, the sword mountain type indenter etc. of a flower arrangement tool can be used. Here, as the indenter, in order to easily and efficiently apply a large external force to the surface of the glass substrate, one having a sharp tip is preferably used.
[0021]
  Further, while pressing the indenter at a predetermined position on the surface of the glass substrate, the indenter and the glass substrate are moved relative to each other, and a convex shape is formed in a stripe shape on the surface of the glass substrate by a chemical etching process. Can do. At this time, a rotatable member such as a cutter knife or an abacus bead is used as the indenter, and a method of moving while pressing against the glass substrate surface can be performed. Also, the free abrasive grains can be sprayed onto the surface of the glass substrate with compressed air at a high speed to form a compressive stress portion where the free abrasive grains collide with the glass surface.
[0022]
  Further, it is preferable to use a plurality of indenters or a die having a shape to be transferred for applying stress, so that a compressive stress portion having a complicated shape can be formed. For example, as an indenter, using a mold engraved with a convex pattern having a predetermined pitch, for example, a pitch of about 1 to 1000 μm, if the convex pattern is pressed against the glass substrate surface and moved while applying external force, The compressive stress portion can be formed at the same pitch as the mold. The material of the indenter used for applying the stress described above can be selected from metals, metal oxides, metal nitrides, diamond, or composites thereof.
[0023]
  In addition, a probe of a scanning probe microscope (SPM) is preferable because the compressive stress portion can be formed at an arbitrary position of the glass substrate by operating the SPM. In this way, the compressive stress portion physically formed on the surface of the glass substrate and the vicinity thereof by application of external force exists in the region extending from 0.02 to 20 μm in the depth direction from the surface of the glass substrate. The depth of the compressive stress part is preferably in the range of 0.02 to 20 μm. When the depth is less than 0.02 μm, almost no protrusions are formed, and when it exceeds 20 μm, cracks are likely to occur in the glass substrate. Furthermore, although there is no restriction | limiting in particular as the width | variety of this compressive stress part, About 1-500 micrometers is preferable in the glass substrate surface.
[0024]
  In the present invention, when the compressive stress portion applied to the glass surface is deep and a large compressive stress is formed, it may be confirmed by polarization microscopy, but it is usually clear by such a simple measurement. There are many cases that cannot be confirmed.
[0025]
  Although it is possible to form a compressive stress part by the method of manually pressing and sweeping the blade of the cutter knife on the surface of the glass substrate, the strength of the stress that presses the indenter depends on the depth of the compressive stress part to be formed. It is more desirable to control because it affects. For example, a scratch tester or a Vickers hardness tester can be used in addition to the SPM. In addition, it can be performed while applying ultrasonic waves to the indenter. When an external force is applied while the glass substrate surface is wet with water, when a large stress is locally applied to the glass surface and minute scratches occur, water enters the substrate from there and grows cracks. The application of external force by the indenter is preferably performed under dry air.
[0026]
  When the compressive stress portion is formed by pressing the indenter, a dent portion as shown in FIG. 1 described later is formed. Therefore, when etching is performed with the dent portion remaining, the cross-sectional shape of the protrusion is As shown in FIG. 1, it may be substantially V-shaped or caldera-shaped. Therefore, an etching process may be performed after removing the dent generated in the vicinity of the center of the external force application part by a surface treatment as necessary. As the surface treatment, it is necessary to prevent the glass substrate surface from being scratched, and therefore it is preferable to polish using a free abrasive having a hardness equal to or less than the hardness of the glass substrate, Further, the free abrasive grains are preferably spherical, and for example, colloidal silica can be used.
[0027]
  In the microfabrication method of the present invention, the above-mentioned SiO is used as the glass substrate.2And Al2OThreeWhen using a glass base material containing as an essential component, an acidic solution is used as an etching solution. This acidic liquid is produced from the glass substrate by SiO.2It is necessary to selectively elute components other than the above, and the selective elution amount is required to be different between the compressive stress portion and the other normal portion in the etching treatment with the etching solution.
[0028]
  Therefore, the etching solution is preferably an aqueous solution having a pH of 5 or less. It is Al that is selectively eluted from the glass substrate by the etching process.2OThreeTherefore, the etching solution is required to be close to acidity. As such an etchant, an acidic aqueous solution containing fluorine ions, for example, a hydrofluoric acid aqueous solution can be used.
[0029]
  The acidic etching solution may be one containing at least one selected from sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, sulfamic acid, oxalic acid, tartaric acid, malic acid and citric acid. . Thus, when an etching process is performed with an acidic etchant, Al2OThreeSome of the components that make up the glass elute into the etchant, and the glass substrate surface has SiO2An altered layer in which the skeleton remains is formed. Therefore, after the etching treatment with the etching solution, it can be further washed with an alkaline aqueous solution having a pH of 7 or more. Thereby, the deteriorated layer can be removed.
[0030]
  In this way, a convex protrusion can be formed on the surface of the glass substrate by applying an external force partially to the surface of the glass substrate and then chemically etching the surface. Since the position and height of the protrusion can be controlled by physical conditions, it can be used as a surface microfabrication technique for glass substrates used in optical components..
[0031]
FIG.These are process drawings which show an example of the fine processing method of the glass base material of this invention, Comprising: It is a case where a dotted | punctate convex part is formed in the glass base material surface. FIG. 1A shows a state in which an external force is applied (A) to the glass substrate 1 by the indenter 2, and FIG. 1B shows a concave surface generated when an external force is applied by pressing the indenter against the glass substrate 1. 3 and the compressive-stress provision part 4 are shown. (C) shows the state in which the glass substrate obtained in the step (b) is subjected to a chemical etching treatment, and the convex shape 5 including the compressive stress applying portion 4 is formed. In addition, 6 is a deteriorated layer produced | generated by the chemical etching process, 7 is the surface of this deteriorated layer. (D) shows the state which performed the washing process by alkaline aqueous solution to the glass base material 1 obtained at the said (c) process, and removed the deteriorated layer 6. FIG. In addition, between the said (b) process and (c) process, the process of grind | polishing the recessed surface 3 and removing a dent can be provided if desired.
[0032]
  FIG. 2 is a process diagram showing a different example of the glass substrate microfabrication method of the present invention, in which a stripe-shaped convex portion is formed on the surface of the glass substrate 1. FIG. 2A shows a state in which an indenter 8 is pressed against the glass substrate 1 and an external force is applied (B) while sweeping to form a compressive stress applying portion 9. (B) shows the state in which the striped convex shape 10 including the compressive stress applying portion 9 is formed by subjecting the glass substrate 1 obtained in the step (a) to chemical etching. Reference numeral 11 denotes an altered layer generated by a chemical etching process. (C) shows a state where the glass substrate 1 obtained in the step (b) has been subjected to a washing treatment with an alkaline aqueous solution to remove the altered layer 11.
[0033]
  FIG. 3 is an explanatory view showing a mechanism for forming convex portions in the fine processing method for a glass substrate of the present invention. As shown in FIG. 3A, the compressive stress applying portion 13 formed in the vicinity of the surface of the glass substrate 14 is adjusted in shape, for example, in the depth direction and in the horizontal direction, according to the external force application condition by the indenter. can do. In this figure, it includes those having the maximum depth H from the glass surface. Further, as shown in (b), the compressive stress applying part 13 is etched shallowly in the depth direction by the chemical etching process (the etching rate is relatively small in this part), and the compressive stress applying part 13 is obtained. The glass other than the portion 12 is etched deeper than the compressive stress applying portion 13. Thereby, the uneven | corrugated pattern corresponding to the compressive-stress provision part 13 is formed. In addition, 13 'is a convex part and 12' is a flat part.
[0034]
  The altered layer 15 is made of an alkali component (R2O) and alkaline earth component (R′O) are selectively eluted, and as a result, are composed of a silica-rich component that is considered to have fine voids, so that the mechanical properties are inferior. Therefore, it is preferable to remove this deteriorated layer. (C) shows a state after the altered layer 15 is dissolved and removed with an alkaline aqueous solution. In this way, irregularities are formed corresponding to the shape of the compressive stress applying portion 13 of (a). In addition, 13 "is a convex part and 12" is a flat part.
[0035]
  In the fine processing method of the glass substrate of the present invention, the dot array convex shape and the stripe pattern convex shape can be formed on the surface of the glass substrate by applying compressive stress in a dotted or linear manner. Various regularly arranged convex shapes can be formed without using a photolithography technique by changing the interval between the compressive stress application points in an inclined manner.
[0036]
  The glass substrate for microfabrication of the present invention has a region in the vicinity of the surface of the glass substrate that has a different etching rate with respect to the etching solution to be used from the other parts, and a chemical etching treatment with the etching solution. Material surfaceConvexHave the ability to form. Specifically, on the surface of the glass substrate and in the vicinity thereof, the compressive stress differs from the other parts in the etching rate for the etchant used.PartAnd has a convex shape on the glass substrate surface by chemical etching treatment with the etching solution.ShapeThe thing which has the capability which can be formed can be mentioned. In the glass substrate for microfabrication, the same glass substrate as that described in the above-described microfabrication method for a glass substrate can be preferably used as the glass base material constituting the glass substrate.
[0037]
  Moreover, it has a compressive stress part on the surface of the glass base material and its vicinity, and can form a convex part with a height of 0.06-1 μm when the glass base material surface is first chemically etched by 1 μm. Is preferred. In addition, regular compressive stress on the surface of the glass substrate and its vicinityPartHas a regular convex shape on the glass substrate surface by chemical etching treatmentShapeThose capable of forming a turn are preferred. The present invention also provides the surface of the glass substrate according to the present invention described above by the microfabrication method.ConvexA microfabricated glass product is also provided.
[0038]
  FIG. 4 is a plan view (b) and a front view (b) showing different examples of the microfabricated glass product of the present invention. In FIG. 4, (a) shows an example in which the convex portions are regularly arranged in a dotted pattern, (b) shows an example in which the convex portions are arranged in a stripe shape, and (c) shows that the convex portions are inclined and An example in which dots are regularly arranged is shown. Such a microfabricated glass product is suitable as a micro optical element such as a microlens, a microprism, or a diffraction grating.
[0039]
【Example】
  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples. Table 1 shows the compositions of the glass substrates used in the examples and comparative examples.
[0040]
[Table 1]
Figure 0003953760
[0041]
  Example 1
  A diamond indenter having a spherical shape with a radius of curvature of 5 μm at the tip is pressed against the glass substrate surface of composition 1 using a Resca scratch tester CSR-02 type, and is swept linearly, thereby compressive stress having a recess. Part was formed. The glass substrate was immersed in a hydrofluoric acid aqueous solution having a pH of 2.8, and further immersed in an alkaline aqueous solution having a pH of 12 to be etched by 13 μm. Thus, a test piece of Example 1 was produced. When the surface shape of the test piece was observed with a surface roughness meter (“Alpha-step 500 type” manufactured by Tencor), a ridge-like protrusion having a height of 6.8 μm and a cross section of a mountain shape along the portion where the compressive stress portion was formed. Was formed.
[0042]
  Example 2
  A composition 3 was used for the glass substrate, a compressive stress portion was formed by the same method as in Example 1, and 1.0 μm etching was performed to prepare a test piece of Example 2. When the surface shape of this test piece was observed with a surface roughness meter, a ridge-like projection having a height of 0.25 μm and a cross section of a mountain was formed along the portion where the compressive stress portion was formed.
[0043]
  Example 3
  A composition 4 was used for the glass substrate, a compressive stress portion was formed in the same manner as in Example 1, and etched by 3.5 μm to prepare a test piece of Example 3. When the surface shape of this test piece was observed with a surface roughness meter, a ridge-like protrusion having a height of 0.54 μm and a cross section of a mountain was formed along the portion where the compressive stress portion was formed.
[0044]
  Example 4
  A composition 5 was used for the glass substrate, a compressive stress portion was formed in the same manner as in Example 1, and etched by 3.0 μm to prepare a test piece of Example 4. When the surface shape of the test piece was observed with a surface roughness meter, a ridge-like projection having a height of 1.1 μm and a mountain-shaped cross section was formed along the portion where the compressive stress portion was formed.
[0045]
  Example 5
  A composition 6 was used for the glass substrate, a compressive stress portion was formed in the same manner as in Example 1, and 0.26 μm was etched to prepare a test piece of Example 5. When the surface shape of this test piece was observed with a surface roughness meter, a ridge-like protrusion having a height of 0.14 μm and a cross section of a mountain was formed along the portion where the compressive stress portion was formed.
[0046]
  Example 6
  A commercially available cutter blade (for NT cutter L-500) having a tip blade thickness of 0.06 mm is pressed against the surface of the glass substrate of composition 1 and manually swept, thereby having a dent. A compressive stress part was formed. The glass substrate was immersed in a hydrofluoric acid aqueous solution and further immersed in an alkaline aqueous solution having a pH of 12 to perform 2.5 μm etching, thereby preparing a test piece of Example 6. When the surface shape of the test piece was observed with a surface roughness meter, ten ridge-like protrusions having a width of 60 μm, a height of 1.2 μm and a trapezoidal cross section were formed along the portion where the compressive stress portion was formed. Even though the compressive stress portion was manually formed, all the protrusions had the same width, height, and shape.
[0047]
  Example 7
  The same cutter blade as in Example 6 was pressed against a glass substrate of composition 1 and 10 lines were swept linearly, thereby forming a compressive stress portion having a dent. At this time, the glass substrate was placed on a sample stage whose position can be controlled in units of 10 μm in the XY directions, and linear compressive stress portions were formed at a pitch of 120 μm. This glass substrate was immersed in a mixed aqueous solution of hydrofluoric acid and sulfuric acid having a pH of 1.4, and further immersed in an alkaline aqueous solution having a pH of 12 to perform 2.5 μm etching, whereby a test piece of Example 7 was produced. When the surface shape of the test piece was observed with a surface roughness meter, ridge-like projections having a width of 60 μm, a height of 1.3 μm, and a trapezoidal cross section were formed at a pitch of 120 μm.
[0048]
  Example 8
  The same cutter blade as in Example 6 was pressed against a glass substrate of composition 1 and 10 lines were swept linearly, thereby forming a compressive stress portion having a dent. At this time, the glass substrate was placed on a sample stage whose position can be controlled in units of 10 μm in the XY directions, and linear compressive stress portions were formed at a pitch of 120 μm. And after this, it grind | polished 50 nm using the slurry in which colloidal silica was mixed, and the said dent part was removed. Next, this glass substrate was immersed in an aqueous hydrofluoric acid solution, and further immersed in an alkaline aqueous solution having a pH of 12 to perform 2.5 μm etching, whereby a test piece of Example 8 was produced. When the surface shape of the test piece was observed with a surface roughness meter, ridge-like protrusions having a width of 60 μm, a height of 1.2 μm and a trapezoidal cross section were formed at a pitch of 120 μm. Compared with Example 7, the top of the protrusion having a trapezoidal cross section could be flattened, while the width and height of the protrusion were not changed by polishing.
[0049]
  Example 9
  A 10 mm square silicon mold with a V-shaped groove with a pitch of 25 μm and a depth of 13 μm is swept in the direction of the pressing groove with an edge on a glass substrate of composition 1, thereby forming a compressive stress part did. The glass substrate was immersed in a hydrofluoric acid aqueous solution to be etched by 2.5 μm, and a test piece of Example 9 was produced. When the surface shape of the test piece was observed with an AFM (Atomic Force Microscope), the ridge-like projections having a width of 10 μm, a height of 1.2 μm and a cross-section of the mountain along the portion where the compressive stress portion was formed maintained a pitch of 25 μm. It was formed as it was.
[0050]
  Example 10
  A diamond-coated silicon single crystal AFM probe having a spring constant of 46 N / m and a tip having a radius of curvature of 10 nm is applied to the surface of a glass substrate of composition 1 using an AFM apparatus (“M5 type” manufactured by Thermo Microscopes). Five lines were pressed and swept in a straight line, thereby forming compressive stress portions having dent portions at a pitch of 1 μm. The glass substrate was immersed in a hydrofluoric acid aqueous solution to be etched by 0.5 μm, and a test piece of Example 10 was produced. When the surface shape of the test piece was observed with an AFM, ridge-like projections having a width of 1 μm, a height of 0.16 μm, and a mountain-shaped cross section were formed at a pitch of 1 μm.
[0051]
  Example 11
  While a slurry containing 17 vol% of an alumina abrasive having a particle diameter of 5 μm was blown out in a mist form from a 90 × 2.0 mm nozzle with compressed air of 0.05 MPa, the nozzle was blown at a speed of 25 mm / s and the glass base of composition 1 The surface of the material was scanned and sprayed to form a number of compressive stress portions having dents. And after that, it grind | polished 60 nm using the slurry which mixed colloidal silica, and the said dent part was removed. This glass substrate was immersed in a hydrofluoric acid aqueous solution, and further immersed in an alkaline aqueous solution having a pH of 12 to etch 0.24 μm, thereby preparing a test piece of Example 11. Then, when the surface shape of the test piece was observed with AFM, 84 fine projections were formed on the surface of the test piece per 10 μm square, and the shape was a substantially circular chevron shape with a bottom surface of 0.57 μm in diameter. The protrusion height was 0.13 μm.
[0052]
  Example 12
  The same cutter blade as that of Example 6 was pressed against the surface of the glass substrate of composition 1 and manually swept 10 linearly, thereby forming a compressive stress portion having a dent. The glass substrate was immersed in a mixed aqueous solution (pH 1.4) of hydrofluoric acid and sulfuric acid to etch 1.0 μm, and a test piece of Example 12 was produced. When the surface shape of the test piece was observed with a surface roughness meter, ten ridge-like protrusions having a width of 60 μm, a height of 0.55 μm and a trapezoidal cross section were formed along the portion where the compressive stress portion was formed.
[0053]
  Example 13
  A composition 7 was used for the glass substrate, a compressive stress portion was formed in the same manner as in Example 12, and 0.95 μm was etched to prepare a test piece of Example 13. When the surface shape of the test piece was observed with a surface roughness meter, a ridge-like protrusion having a height of 0.71 μm and a cross section of a mountain was formed along the portion where the compressive stress portion was formed.
[0054]
  Example 14
  A composition 8 was used for the glass substrate, a compressive stress portion was formed by the same method as in Example 12, and the specimen of Example 14 was prepared by etching 1.1 μm. When the surface shape of this test piece was observed with a surface roughness meter, a ridge-like protrusion having a height of 0.02 μm and a cross section of a mountain was formed along the portion where the compressive stress portion was formed.
[0055]
  Example 15
  A composition 9 was used for the glass substrate, a compressive stress portion was formed in the same manner as in Example 12, and the test piece of Example 15 was produced by etching 0.20 μm. When the surface shape of the test piece was observed with a surface roughness meter, a ridge-like projection having a height of 0.10 μm and a cross section of a mountain was formed along the portion where the compressive stress portion was formed..
[0056]
ratioComparative Example 1
  A composition 2 was used for the glass substrate, a compressive stress portion was formed in the same manner as in Example 1, and 2.7 μm was etched to prepare a test piece of Comparative Example 1. When the surface shape of the test piece was observed with a surface roughness meter, no protrusion was formed on the portion where the compressive stress portion was formed. Al contained in glass2OThreeTherefore, it is considered that there was almost no change in the amount of selective elution at the compressive stress portion.
[0057]
  Comparative Example 2
  A compressive stress portion was formed on the glass substrate of composition 1 by the same method as in Example 6. The glass substrate was immersed in a mixed aqueous solution of hydrofluoric acid and ammonium fluoride having a pH of 5.6 to etch 1.0 μm, and a test piece of Comparative Example 2 was produced. When the surface shape of the test piece was observed with a surface roughness meter, no protrusion was formed on the portion where the compressive stress portion was formed. The etching solution used for the etching process is neutral, and the acid resistance is low.2OThreeIt is probable that selective elution did not occur.
[0058]
  Comparative Example 3
  A polycarbonate mold of 10 mm square in which V-shaped grooves having a pitch of 25 μm and a depth of 13 μm were engraved was swept in the direction of the pressing groove with an edge on the glass substrate of composition 1. Etching this glass substrate in a hydrofluoric acid aqueous solution for 2.5 μm,Comparative Example 3A test piece was prepared. The surface shape of the test piece was observed with AFM, but no protrusion was formed. Since the polycarbonate resin is softer than glass, it is considered that sufficient stress cannot be applied to form the compressive stress portion. The above results are summarized in Table 2.
[0059]
[Table 2]
Figure 0003953760
[0060]
[Table 3]
Figure 0003953760
[0061]
[Table 4]
Figure 0003953760
[0062]
  In addition, in FIG.2Content -Al2OThreeThe relationship between the content (mol%) and the protrusion formation efficiency is shown in a graph, and FIG. 6 is a graph showing the relationship between the etching amount and the protrusion height in Example 1 and Comparative Example 1. FIG. 7 is a plot showing the influence of the total content of alkaline earth metal oxides on the protrusion formation efficiency. The protrusion formation efficiency is a value expressed by the height (μm) of the protrusion formed when etching is performed by 1 μm.
[0063]
  The method of forming the compressive stress portion of the microfabrication method of the present invention is such that, for example, in the case of a transmissive diffraction grating element for a laser beam splitter, there are irregularities with a grating frequency (pitch) of 9 to 14 nm (70 to 110 lines / mm). In the case of a reflection type diffraction grating element, it is required to have irregularities with a grating frequency (pitch) of 0.8 to 3.3 nm (300 to 1200 lines / mm). Such an optical element is used in a photolithographic method. This is the preferred method for manufacturing inexpensively without using expensive methods..
[0064]
【The invention's effect】
  According to the microfabrication method for a glass substrate of the present invention, a region having an etching rate different from that of other portions is provided on the surface of the glass substrate and in the vicinity thereof, and chemical etching treatment is performed. Position, height and width are controlledConvexThe shape can be formed inexpensively and efficiently. The microfabricated glass product produced by this method is suitably used for micro optical elements such as microlenses, microprisms, and diffraction gratings.
[Brief description of the drawings]
[0065]
FIG. 1 is a process diagram showing an example of a fine processing method of a glass substrate of the present invention.
FIG. 2 is a process diagram showing a different example of the glass substrate microfabrication method of the present invention.
FIG. 3 is an explanatory view showing a mechanism for forming convex portions in the glass substrate microfabrication method of the present invention.
FIG. 4 is a plan view and a front view showing different examples of the microfabricated glass product of the present invention.
FIG. 5 shows SiO in the examples.2Content -Al2OThreeIt is a graph which shows the relationship between content (mol%) and protrusion formation efficiency.
6 is a graph showing the relationship between the etching amount and the protrusion height in Example 1 and Comparative Example 1. FIG.
FIG. 7 is a plot diagram showing the influence of the total content of alkaline earth metal oxides on the protrusion formation efficiency in Examples and Comparative Examples.
[Explanation of symbols]
[0066]
1 Glass substrate
2 Indenter
3 concave surface
4 Compression stress applying part
5 Convex shape
6 Altered layer
7 Altered layer surface
8 Indenter
9 Compression stress applying part
10 Striped convex shape
11 Altered layer
12 Parts other than compressive stress applying part
12 'flat part
12 ″ flat part
13 Compression stress applying part
13 'Convex
13 ″ convex
14 Glass substrate
15 Altered layer

Claims (13)

ガラス基材の表面及びその近傍に、使用するエッチング液に対するエッチングレートが他の部分と異なる圧縮応力部を、該ガラス基材表面の所定個所に１個又は複数個の圧子を押し当てて外力を印加して物理的に形成し、次いでこのガラス基材を当該エッチング液により化学的エッチング処理して、ガラス基材表面に凹凸を形成させることを特徴とするガラス基材の微細加工方法であって、該ガラス基材を構成する母材が、ＳｉＯ 2 及び１モル％以上のＡｌ 2 Ｏ 3 を含むことを特徴とするガラス基材の微細加工方法。 An external force is applied to the surface of the glass substrate and the vicinity thereof by pressing a compressive stress portion having an etching rate different from that of the other portion on the surface of the glass substrate and pressing one or more indenters at predetermined locations on the surface of the glass substrate physically formed by applying and then the glass substrate is chemically etched with the etching solution, a fine processing method for a glass substrate, characterized in that to form the uneven surface of the glass substrate A glass substrate fine processing method , wherein the base material constituting the glass substrate contains SiO 2 and 1 mol% or more of Al 2 O 3 . ガラス基材を構成する母材のＳｉＯ2含有量とＡｌ2Ｏ3含有量との差（ＳｉＯ2含有量−Ａｌ2Ｏ3含有量）が４０〜６７モル％である請求項１記載のガラス基材の微細加工方法。The difference between the SiO 2 content and Al 2 O 3 content of the base material constituting the glass substrate (SiO 2 content -Al 2 O 3 content) 40-67 mol% der Ru請 Motomeko 1 Symbol A fine processing method of a glass substrate. 前記ＳｉＯ2含有量−Ａｌ2Ｏ3含有量が４７〜５７モル％である請求項２記載のガラス基材の微細加工方法。 The SiO 2 content -Al 2 O 3 content of 47-57 mol% claim 2 microfabrication method of a glass substrate according. ガラス基材を構成する母材がアルカリ土類金属酸化物３〜１６モル％を含む請求項１ないし３のいずれかに記載のガラス基材の微細加工方法。 The glass substrate fine processing method according to any one of claims 1 to 3 , wherein the base material constituting the glass substrate contains 3 to 16 mol% of an alkaline earth metal oxide . アルカリ土類金属酸化物の含有量が３〜１１モル％である請求項４記載のガラス基材の微細加工方法。 The glass substrate fine processing method according to claim 4 , wherein the content of the alkaline earth metal oxide is 3 to 11 mol% . ガラス基材表面の所定個所に圧子を等間隔で押し当てながら、該圧子とガラス基材とを相対的に移動させて外力を印加し、化学的エッチング処理によりガラス基材表面に凸形状をストライプ状に形成させる請求項１ないし５のいずれかに記載のガラス基材の微細加工方法。While pressing the indenter at a predetermined location on the glass substrate surface at equal intervals, the indenter and the glass substrate are moved relative to each other to apply an external force, and the convex shape is striped on the glass substrate surface by chemical etching. The method for finely processing a glass substrate according to any one of claims 1 to 5, wherein the glass substrate is formed into a shape. ガラス基材表面の所定個所に、圧子として所定のピッチを有する凸パターンを刻んだ金型を用い、該凸パターンを押し当てて外力を印加しながら移動させる請求項１ないし５のいずれかに記載のガラス基材の微細加工方法。A predetermined position of the glass substrate surface, using a mold carved convex pattern having a predetermined pitch as the indenter, according to any one of claims 1 to move while applying a force by pressing a convex pattern 5 A fine processing method of a glass substrate. 圧縮応力部がガラス基材表面から、深さ０．０２〜２０μｍにわたる領域に存在する請求項１ないし７のいずれかに記載のガラス基材の微細加工方法。The glass substrate microfabrication method according to any one of claims 1 to 7 , wherein the compressive stress portion is present in a region extending from the glass substrate surface to a depth of 0.02 to 20 µm. 圧縮応力部を形成後、化学的エッチング処理を施す前に、外力印加部の中央近傍に生じた凹みを研磨により除去する請求項１ないし８のいずれかに記載のガラス基材の微細加工方法。The method for microfabricating a glass substrate according to any one of claims 1 to 8 , wherein after the compressive stress portion is formed, the dent generated in the vicinity of the center of the external force application portion is removed by polishing before chemical etching treatment. エッチング液のｐＨが５以下である請求項１ないし９のいずれかに記載のガラス基材の微細加工方法。The glass substrate microfabrication method according to any one of claims 1 to 9, wherein the pH of the etching solution is 5 or less. エッチング液がフッ素イオンを含む請求項１０記載のガラス基材の微細加工方法。The glass substrate fine processing method according to claim 10 , wherein the etching solution contains fluorine ions. エッチング液が硫酸、塩酸、硝酸、リン酸、スルファミン酸、シュウ酸、酒石酸、リンゴ酸及びクエン酸の中から選ばれる少なくとも一種を添加したものである請求項１０又は１１記載のガラス基材の微細加工方法。The fine glass substrate according to claim 10 or 11 , wherein the etching solution contains at least one selected from sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, sulfamic acid, oxalic acid, tartaric acid, malic acid and citric acid. Processing method. エッチング液による化学的エッチング処理後、この化学的エッチング処理により形成したガラス表面の変質層をアルカリ性水溶液で洗浄処理する請求項１０ないし１２のいずれかに記載のガラス基材の微細加工方法。After chemical etching treatment with an etchant, fine processing method for a glass substrate according to any one of claims 10 to 12 affected layer formed glass surface is washed treated with an alkaline aqueous solution by the chemical etching process.
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