JP3666610B2 - Alkali-free glass substrate - Google Patents
Alkali-free glass substrate Download PDFInfo
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- JP3666610B2 JP3666610B2 JP21810395A JP21810395A JP3666610B2 JP 3666610 B2 JP3666610 B2 JP 3666610B2 JP 21810395 A JP21810395 A JP 21810395A JP 21810395 A JP21810395 A JP 21810395A JP 3666610 B2 JP3666610 B2 JP 3666610B2
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- glass substrate
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- 239000011521 glass Substances 0.000 title claims description 71
- 239000000758 substrate Substances 0.000 title claims description 39
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 6
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 5
- 229910010413 TiO 2 Inorganic materials 0.000 claims description 5
- 239000003513 alkali Substances 0.000 claims description 4
- 239000000203 mixture Substances 0.000 claims description 3
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 36
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 20
- 239000010408 film Substances 0.000 description 13
- 239000000126 substance Substances 0.000 description 13
- 238000004031 devitrification Methods 0.000 description 12
- 239000004973 liquid crystal related substance Substances 0.000 description 7
- 238000000034 method Methods 0.000 description 7
- 230000000694 effects Effects 0.000 description 6
- 230000008569 process Effects 0.000 description 6
- 239000002253 acid Substances 0.000 description 5
- 239000011159 matrix material Substances 0.000 description 5
- 238000001259 photo etching Methods 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
- 229910000272 alkali metal oxide Inorganic materials 0.000 description 3
- 239000007795 chemical reaction product Substances 0.000 description 3
- 238000005530 etching Methods 0.000 description 3
- 230000004907 flux Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000000155 melt Substances 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 239000005354 aluminosilicate glass Substances 0.000 description 2
- 229910052788 barium Inorganic materials 0.000 description 2
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000005388 borosilicate glass Substances 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000001771 impaired effect Effects 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 238000011282 treatment Methods 0.000 description 2
- 239000013585 weight reducing agent Substances 0.000 description 2
- DDFHBQSCUXNBSA-UHFFFAOYSA-N 5-(5-carboxythiophen-2-yl)thiophene-2-carboxylic acid Chemical compound S1C(C(=O)O)=CC=C1C1=CC=C(C(O)=O)S1 DDFHBQSCUXNBSA-UHFFFAOYSA-N 0.000 description 1
- 238000007088 Archimedes method Methods 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 229910000287 alkaline earth metal oxide Inorganic materials 0.000 description 1
- 239000012670 alkaline solution Substances 0.000 description 1
- -1 alkalis Substances 0.000 description 1
- 229910021417 amorphous silicon Inorganic materials 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 229910052906 cristobalite Inorganic materials 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000010828 elution Methods 0.000 description 1
- 229910052634 enstatite Inorganic materials 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 239000006025 fining agent Substances 0.000 description 1
- 239000005357 flat glass Substances 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- BBCCCLINBSELLX-UHFFFAOYSA-N magnesium;dihydroxy(oxo)silane Chemical compound [Mg+2].O[Si](O)=O BBCCCLINBSELLX-UHFFFAOYSA-N 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 238000002834 transmittance Methods 0.000 description 1
- 229910052845 zircon Inorganic materials 0.000 description 1
- GFQYVLUOOAAOGM-UHFFFAOYSA-N zirconium(iv) silicate Chemical compound [Zr+4].[O-][Si]([O-])([O-])[O-] GFQYVLUOOAAOGM-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Liquid Crystal (AREA)
- Glass Compositions (AREA)
Description
【０００１】
【産業上の利用分野】
本発明は、液晶ディスプレイ、ＥＬディスプレイ等のディスプレイ、フィルター、センサー等の基板として用いられる無アルカリガラス基板に関するものである。
【０００２】
【従来の技術】
従来より、液晶ディスプレイ等のフラットパネルディスプレイ、フィルター、センサー等の基板として、ガラス基板が広く使用されている。
【０００３】
この種のガラス基板の表面には、透明導電膜、絶縁膜、半導体膜、金属膜等が成膜され、しかもフォトリソグラフィ−エッチング（フォトエッチング）によって種々の回路やパターンが形成される。これらの成膜、フォトエッチング工程において、ガラス基板には、種々の熱処理や薬品処理が施される。
【０００４】
例えば薄膜トランジスタ（ＴＦＴ）型アクティブマトリックス液晶ディスプレイの場合、ガラス基板上に絶縁膜や透明導電膜が成膜され、さらにアモルファスシリコンや多結晶シリコンのＴＦＴが、フォトエッチングによって多数形成される。このような工程において、ガラス基板は、数百度の熱処理を受けると共に、硫酸、塩酸、アルカリ溶液、フッ酸、バッファードフッ酸等の種々の薬品による処理を受ける。
【０００５】
特にバッファードフッ酸は、絶縁膜のエッチングに広く用いられるが、ガラスを侵食してその表面を白濁させやすく、またガラス成分と反応して反応生成物ができ、これが工程中のフィルターをつまらせたり、基板上に付着することがあり、また塩酸は、ＩＴＯ膜やクロム膜のエッチングに用いられるが、これもガラスを侵食してその表面を変色させたり、ガラス成分と反応して反応生成物ができやすいため、この種のガラス基板には、耐バッファードフッ酸性と耐塩酸性を付与することが大変重要となる。
【０００６】
従ってＴＦＴ型アクティブマトリックス液晶ディスプレイに使用されるガラス基板には、以下のような特性が要求される。
【０００７】
（１）ガラス中にアルカリ金属酸化物が含有されていると、熱処理中にアルカリイオンが成膜された半導体物質中に拡散し、膜特性の劣化を招くため、実質的にアルカリ金属酸化物を含有しないこと。
【０００８】
（２）フォトエッチング工程において使用される種々の酸、アルカリ等の薬品によって劣化しないような耐薬品性を有すること。
【０００９】
（３）成膜、アニール等の工程における熱処理によって、熱収縮しないこと。そのため高い歪点を有すること。例えば多結晶シリコンＴＦＴ−ＬＣＤの場合、その工程温度が約６００℃以上であるため、このような用途のガラス基板には、歪点が６５０℃以上であることが要求される。
【００１０】
また溶融性、成形性を考慮して、この種のガラス基板には、以下のような特性も要求される。
【００１１】
（４）ガラス中に基板として好ましくない溶融欠陥が発生しないよう、溶融性に優れていること。
【００１２】
（５）ガラス中に溶融、成形中に発生する異物が存在しないように、耐失透性に優れていること。
【００１３】
また近年、ＴＦＴ型アクティブマトリックス液晶ディスプレイ等の電子機器は、パーソナルな分野への利用が進められており、機器の軽量化が要求されている。これに伴ってガラス基板にも軽量化が要求されており、薄板化が進められている。しかしながらこの種の電子機器は、大型化も進められており、ガラス基板の強度を考慮すると、薄板化については自ずと限界がある。そこでガラス基板の軽量化を図る目的で、ガラスの密度を低くすることが望まれている。
【００１４】
【発明が解決しようとする課題】
従来よりＴＦＴ型アクティブマトリックス液晶ディスプレイ基板に用いられている無アルカリガラスとしては、石英ガラス、バリウム硼珪酸ガラス及びアルミノ珪酸塩ガラスが存在するが、いずれも一長一短がある。
【００１５】
すなわち石英ガラスは、耐薬品性、耐熱性に優れ、低密度であるが、材料コストが高いという難点がある。
【００１６】
またバリウム硼珪酸ガラスとしては、市販品としてコーニング社製＃７０５９が存在するが、このガラスは耐酸性に劣り、フォトエッチング工程においてガラス基板の表面に変質や白濁、荒れが生じやすく、しかも基板からの溶出成分によって薬液を汚染しやすい。さらにこのガラスは、歪点が低いため、熱収縮や熱変形を起こしやすく、耐熱性に劣っている。またその密度も、２．７６ｇ／ｃｍ3 と高い。
【００１７】
アルミノ珪酸塩ガラスは、耐熱性に優れているが、現在市場にあるガラス基板の多くが、溶融性が悪く、大量生産に不向きである。またこのガラス基板は、密度が高かったり、耐バッファードフッ酸性に劣るものが多く、全ての要求特性を満足するものは未だ存在しないというのが実情である。
【００１８】
本発明の目的は、上記した要求特性項目（１）〜（５）の全て満足し、しかも密度が２．６ｇ／ｃｍ3 以下である無アルカリガラス基板を提供することである。
【００１９】
【課題を解決するための手段】
本発明の無アルカリガラス基板は、重量百分率で、ＳｉＯ2 ５０〜６５％、Ａｌ2Ｏ3 １１〜２２％、Ｂ2Ｏ3 ４〜８．９％、ＭｇＯ ３〜１０％、ＣａＯ ０〜４．５％、ＳｒＯ ０．５〜１０％、ＢａＯ ０．５〜９％、ＺｎＯ ０〜５％、ＺｒＯ2 ０〜５％、ＴｉＯ2 ０〜５％、ＭｇＯ＋ＣａＯ＋ＳｒＯ＋ＢａＯ＋ＺｎＯ ５〜２０％の組成を有し、実質的にアルカリ金属酸化物を含有せず、密度が２．６ｇ／ｃｍ3以下であることを特徴とする。
【００２０】
また本発明の無アルカリガラス基板は、好ましくは、重量百分率で、ＳｉＯ2 ５０〜６５％、Ａｌ2 Ｏ3 １１〜２２％、Ｂ2 Ｏ3 ４〜８．９％、ＭｇＯ３〜１０％、ＣａＯ ０〜２％、ＳｒＯ ０．５〜１０％、ＢａＯ ０．５〜９％、ＺｎＯ ０〜５％、ＺｒＯ2 ０〜１．８％、ＴｉＯ2 ０〜５％、ＭｇＯ＋ＣａＯ＋ＳｒＯ＋ＢａＯ＋ＺｎＯ ５〜２０％の組成を有することを特徴とする。
【００２１】
【作用】
以下、本発明の無アルカリガラス基板の構成成分を上記のように限定した理由を説明する。
【００２２】
ＳｉＯ2 は、ガラスのネットワークフォーマーとなる成分であって、その含有量は、５０〜６５％である。５０％より少ないと、耐薬品性、特に耐酸性が低下すると共に歪点が低くなるため耐熱性が悪くなり、また６５％より多いと、高温粘度が大きくなり、溶融性が悪くなると共にクリストバライトの失透物が析出しやすくなる。
【００２３】
Ａｌ2 Ｏ3 は、ガラスの耐熱性、耐失透性を高めると共に、密度を低下させるために不可欠な成分であり、その含有量は、１１〜２２％である。１１％より少ないと、失透温度が著しく上昇し、ガラス中に失透異物が生じやすくなる。また２２％より多いと、耐酸性、特に耐バッファードフッ酸性が低下し、ガラス基板の表面に白濁が生じやすくなる。
【００２４】
Ｂ2 Ｏ3 は、融剤として働き、粘性を下げ、溶融性を改善すると共に密度を低下させるための成分であり、その含有量は、４〜８．９％である。４％より少ないと、融剤としての働きが不十分となると共に、ガラスの密度が高くなり、しかも耐バッファードフッ酸性が低下する。また８．９％より多いと、耐塩酸性が低下するため好ましくない。
【００２５】
ＭｇＯは、歪点を下げずに高温粘性を下げ、ガラスの溶融性を改善する作用を有しており、二価のアルカリ土類酸化物の中で、最も密度を下げる効果が大きい成分であり、その含有量は、３〜１０％である。３％より少ないと、上記の効果が小さくなり、１０％より多いと、失透温度が著しく上昇し、エンスタタイト（ＭｇＯ・ＳｉＯ2 ）の結晶異物がガラス中に析出しやすくなると共に、ガラスの耐バッファードフッ酸性が著しく悪化する。
【００２６】
ＣａＯも、ＭｇＯと同様に歪点を下げずに高温粘性を下げ、ガラスの溶融性を改善する作用を有する成分であり、その含有量は、０〜４．５％、好ましくは０〜２％である。４．５％より多いと、ガラスの耐バッファードフッ酸性が著しく悪化するため好ましくない。すなわちガラスをバッファードフッ酸で処理する際に、ガラス中のＣａＯ成分と、バッファードフッ酸による反応生成物が、ガラス表面に多量に析出してガラス基板を白濁させやすくなると共に、反応生成物によってガラス基板上に形成される素子や薬液が汚染されやすくなるため好ましくない。
【００２７】
ＳｒＯとＢａＯは、共にガラスの耐薬品性を向上させると共に、失透性を改善するための成分であるが、多量に含有させると、溶融性を損なうと共にガラスの密度が高くなるため好ましくない。従ってＳｒＯの含有量は、０〜１０％、好ましくは０．５〜１０％であり、ＢａＯの含有量は、０．５〜９％である。すなわちＳｒＯとＢａＯを共存させると、失透性を改善する効果がより一層大きくなり、ガラスの溶融成形性を大幅に向上させることが可能となる。
【００２８】
ＺｎＯは、耐バッファードフッ酸性を改善すると共に、失透性を改善する成分であり、その含有量は、０〜５％である。５％より多いと、逆にガラスが失透しやすくなると共に、歪点が低下するため耐熱性が得られない。
【００２９】
ただしＭｇＯ、ＣａＯ、ＳｒＯ、ＢａＯ及びＺｎＯの合量が５％より少ないと、ガラスの高温での粘性が高くなり、溶融性が悪くなると共に、ガラスが失透しやすくなり、２０％より多いと、ガラスの密度が高くなり、２．６ｇ／ｃｍ3 以下にするのが困難となる。
【００３０】
ＺｒＯ2 は、ガラスの耐薬品性、特に耐酸性を改善すると共に、高温粘性を下げて溶融性を向上させる成分であり、その含有量は、０〜５％、好ましくは０〜１．８％である。５％より多いと、失透温度が上昇し、ジルコンの失透異物が析出しやすくなる。
【００３１】
ＴｉＯ2 は、耐薬品性、特に耐バッファードフッ酸性を改善すると共に、高温粘性を低下し、溶融性を向上させる成分であり、その含有量は、０〜５％である。５％より多いと、ガラスに着色を生じ、透過率が低下するためディスプレイ用ガラス基板として好ましくない。
【００３２】
また本発明においては、上記成分以外にも、特性を損なわない範囲で、他の成分を添加させることが可能であり、例えば清澄剤としてＡｓ2 Ｏ3 、Ｓｂ2 Ｏ3 、Ｆ2 、Ｃｌ2 、ＳＯ3 等の成分を添加させることが可能である。
【００３３】
ただし一般に融剤として使用されるＰｂＯとＰ2 Ｏ5 は、ガラスの耐薬品性を著しく低下させるため、本発明においては添加を避けるべきであり、特にＰｂＯは、溶融時に融液の表面から揮発し、環境を汚染する虞れもあるため好ましくない。
【００３４】
【実施例】
以下、本発明の無アルカリガラス基板を実施例に基づいて詳細に説明する。
【００３５】
表１、２は、実施例のガラス（試料Ｎｏ．１〜１０）と比較例のガラス（試料Ｎｏ．１１〜１３）を示すものである。
【００３６】
【表１】
【表２】
表中の各試料は、次のようにして作製した。まず表の組成となるようにガラス原料を調合し、白金坩堝に入れ、１５８０℃で、２４時間溶融した後、カーボン板上に流し出し、板状に成形した。次いでこれらの板状ガラスの両面を光学研磨することによってガラス基板とした。
【００３９】
表から明らかなように、実施例であるＮｏ．１〜１０の各試料は、いずれも密度が２．５９ｇ／ｃｍ3 以下、歪点が６６４℃以上、失透温度が１１１８℃以下、１０2.5 ポイズに相当する温度が１６３０℃以下であり、いずれも良好な特性を有していた。またこれらの試料は、耐塩酸性と耐バッファードフッ酸性にも優れていた。
【００４０】
それに対し、比較例であるＮｏ．１１の試料は、実施例に比べて密度が大きいため、重量が大きいと考えられる。しかも歪点が低いため、耐熱性に劣り、且つ、耐塩酸性も悪かった。またＮｏ．１２の試料は、実施例に比べて密度が高く、また歪点が低いため、耐熱性に劣り、しかも耐塩酸性と耐バッファードフッ酸性が悪かった。さらにＮｏ．１３の試料は、実施例に比べて失透温度と高温粘性が大幅に高いため溶融性に劣ると共に、耐塩酸性も悪かった。
【００４１】
尚、密度は、周知のアルキメデス法によって測定したものである。また歪点は、ＡＳＴＭ Ｃ３３６−７１の方法に基づいて測定し、失透温度は、各試料から３００〜５００μｍの粒径を有するガラス粉末を作製し、これを白金ボート内に入れ、温度勾配炉に２４時間保持した後の失透観察によって求めたものである。
【００４２】
また１０2.5 ポイズ温度は、高温粘度である１０2.5 ポイズに相当する温度を示すものであり、この温度が低いほど、溶融成形性に優れていることになる。
【００４３】
さらに耐塩酸性は、各試料を８０℃に保持された１０重量％塩酸水溶液に２４時間浸漬した後、ガラス基板の表面状態を観察することによって評価した。ガラス基板の表面が変色したものを×、全く変化がないものを○で示した。
【００４４】
また耐バッファードフッ酸性は、各試料を、２０℃に保持された３８．７重量％フッ化アンモニウム、１．６重量％フッ酸からなるバッファードフッ酸に３０分間浸漬した後、ガラス基板の表面状態を観察することによって評価した。ガラス基板の表面が白濁したものを×、全く変化のなかったものを○で示した。
【００４５】
【発明の効果】
以上のように本発明の無アルカリガラス基板は、実質的にアルカリ金属酸化物を含有せず、耐熱性、耐薬品性、溶融成形性に優れ、しかも低密度であるため、特に軽量化が要求されるＴＦＴ型アクティブマトリックス液晶ディスプレイに使用されるガラス基板として好適である。[0001]
[Industrial application fields]
The present invention relates to a non-alkali glass substrate used as a substrate for displays such as liquid crystal displays and EL displays, filters, sensors and the like.
[0002]
[Prior art]
Conventionally, glass substrates have been widely used as substrates for flat panel displays such as liquid crystal displays, filters and sensors.
[0003]
A transparent conductive film, an insulating film, a semiconductor film, a metal film, and the like are formed on the surface of this type of glass substrate, and various circuits and patterns are formed by photolithography-etching (photoetching). In these film formation and photoetching steps, the glass substrate is subjected to various heat treatments and chemical treatments.
[0004]
For example, in the case of a thin film transistor (TFT) type active matrix liquid crystal display, an insulating film or a transparent conductive film is formed on a glass substrate, and a large number of amorphous silicon or polycrystalline silicon TFTs are formed by photoetching. In such a process, the glass substrate is subjected to a heat treatment of several hundred degrees and a treatment with various chemicals such as sulfuric acid, hydrochloric acid, an alkaline solution, hydrofluoric acid, and buffered hydrofluoric acid.
[0005]
In particular, buffered hydrofluoric acid is widely used for etching insulating films, but it tends to erode glass and make its surface cloudy, and react with glass components to form reaction products, which clogs the filter in the process. In addition, hydrochloric acid is used for etching ITO films and chromium films, but it also erodes the glass and changes its surface, reacts with glass components, and is a reaction product. Therefore, it is very important to provide buffered hydrofluoric acid resistance and hydrochloric acid resistance to this type of glass substrate.
[0006]
Therefore, the glass substrate used in the TFT type active matrix liquid crystal display is required to have the following characteristics.
[0007]
(1) If an alkali metal oxide is contained in the glass, alkali ions diffuse into the semiconductor material on which the film is formed during the heat treatment, resulting in deterioration of the film characteristics. Do not contain.
[0008]
(2) To have chemical resistance that does not deteriorate due to various acids, alkalis, and other chemicals used in the photoetching process.
[0009]
(3) No thermal contraction due to heat treatment in processes such as film formation and annealing. Therefore, it must have a high strain point. For example, in the case of a polycrystalline silicon TFT-LCD, since the process temperature is about 600 ° C. or higher, the glass substrate for such use is required to have a strain point of 650 ° C. or higher.
[0010]
In consideration of meltability and moldability, this type of glass substrate is also required to have the following characteristics.
[0011]
(4) The glass is excellent in meltability so as not to cause undesirable melting defects in the glass as a substrate.
[0012]
(5) Excellent devitrification resistance so that there is no foreign matter generated during melting and molding in the glass.
[0013]
In recent years, electronic devices such as TFT-type active matrix liquid crystal displays have been used in the personal field, and there is a demand for weight reduction of the devices. In connection with this, the glass substrate is also required to be reduced in weight, and thinning is being promoted. However, this type of electronic device is also being increased in size, and there is a limit to the reduction in thickness in view of the strength of the glass substrate. Therefore, it is desired to reduce the density of the glass for the purpose of reducing the weight of the glass substrate.
[0014]
[Problems to be solved by the invention]
Conventionally, as the alkali-free glass used for the TFT type active matrix liquid crystal display substrate, there are quartz glass, barium borosilicate glass and aluminosilicate glass, all of which have advantages and disadvantages.
[0015]
In other words, quartz glass is excellent in chemical resistance and heat resistance, has a low density, but has a drawback that the material cost is high.
[0016]
In addition, as a barium borosilicate glass, there is a commercially available product # 7059 manufactured by Corning, but this glass is inferior in acid resistance, and the surface of the glass substrate is easily deteriorated, clouded, or roughened in the photoetching process. The chemical solution is easily contaminated by the elution components. Furthermore, since this glass has a low strain point, it tends to cause thermal shrinkage and thermal deformation and is inferior in heat resistance. The density is also high at 2.76 g / cm 3 .
[0017]
Although aluminosilicate glass is excellent in heat resistance, many glass substrates currently on the market have poor meltability and are not suitable for mass production. In addition, many glass substrates are high in density or inferior in buffered hydrofluoric acid resistance, and there is no actual substrate that satisfies all the required characteristics.
[0018]
An object of the present invention is to provide an alkali-free glass substrate that satisfies all of the above required characteristic items (1) to (5) and has a density of 2.6 g / cm 3 or less.
[0019]
[Means for Solving the Problems]
The alkali-free glass substrate of the present invention is, by weight percentage, SiO 2 50 to 65%, Al 2 O 3 11 to 22%, B 2 O 3 4 to 8.9%, MgO 3 to 10%, CaO 0 to 4 0.5 %, SrO 0.5-10 %, BaO 0.5-9%, ZnO 0-5%, ZrO 2 0-5%, TiO 2 0-5%, MgO + CaO + SrO + BaO + ZnO 5-20% It is characterized in that it contains substantially no alkali metal oxide and has a density of 2.6 g / cm 3 or less.
[0020]
Further, the alkali-free glass substrate of the present invention is preferably in a percentage by weight of SiO 2 50 to 65%, Al 2 O 3 11 to 22%, B 2 O 3 4 to 8.9%, MgO 3 to 10%, CaO. 0~2%, SrO 0.5~10%, BaO 0.5~9%, 0~5% ZnO, ZrO 2 0~1.8%, TiO 2 0~5%, MgO + CaO + SrO + BaO + ZnO 5~20% of the composition It is characterized by having.
[0021]
[Action]
Hereinafter, the reason which limited the component of the alkali free glass substrate of this invention as mentioned above is demonstrated.
[0022]
SiO 2 is a component that becomes a glass network former, and its content is 50 to 65%. If it is less than 50%, the chemical resistance, particularly acid resistance is lowered and the strain point is lowered and the heat resistance is deteriorated. If it is more than 65%, the high temperature viscosity is increased, the meltability is deteriorated and the cristobalite is deteriorated. Devitrified materials are likely to precipitate.
[0023]
Al 2 O 3 is an essential component for increasing the heat resistance and devitrification resistance of the glass and reducing the density, and its content is 11 to 22%. When it is less than 11%, the devitrification temperature is remarkably increased, and devitrified foreign matter is easily generated in the glass. On the other hand, when the content is more than 22%, acid resistance, particularly buffered hydrofluoric acid resistance is lowered, and white turbidity is likely to occur on the surface of the glass substrate.
[0024]
B 2 O 3 is a component that acts as a flux, lowers viscosity, improves meltability and lowers density, and its content is 4 to 8.9%. If it is less than 4%, the function as a flux becomes insufficient, the density of the glass increases, and the resistance to buffered hydrofluoric acid decreases. On the other hand, if it exceeds 8.9%, the hydrochloric acid resistance decreases, which is not preferable.
[0025]
MgO has the effect of lowering the high-temperature viscosity without lowering the strain point and improving the meltability of the glass, and is the component that has the greatest effect of reducing the density among divalent alkaline earth oxides. The content is 3 to 10%. When the amount is less than 3%, the above effect is reduced. When the amount is more than 10%, the devitrification temperature is remarkably increased, and enstatite (MgO.SiO 2 ) is easily precipitated in the glass. Resistance to buffered hydrofluoric acid is significantly deteriorated.
[0026]
CaO is also a component having the effect of lowering the high temperature viscosity without lowering the strain point and improving the meltability of the glass, similarly to MgO, and its content is 0 to 4.5%, preferably 0 to 2%. It is. If it exceeds 4.5%, the buffered hydrofluoric acid resistance of the glass is remarkably deteriorated. That is, when the glass is treated with buffered hydrofluoric acid, the CaO component in the glass and the reaction product due to the buffered hydrofluoric acid are deposited in a large amount on the glass surface and the glass substrate tends to become cloudy. This is not preferable because elements and chemicals formed on the glass substrate are easily contaminated.
[0027]
Both SrO and BaO are components for improving the chemical resistance of the glass and improving the devitrification property. However, when contained in a large amount, the meltability is impaired and the density of the glass is increased, which is not preferable. Accordingly, the SrO content is 0 to 10%, preferably 0.5 to 10%, and the BaO content is 0.5 to 9%. That is, when SrO and BaO coexist, the effect of improving devitrification is further increased, and the melt moldability of glass can be greatly improved.
[0028]
ZnO is a component that improves buffered hydrofluoric acid resistance and also improves devitrification, and its content is 0 to 5%. If it exceeds 5%, the glass tends to be devitrified, and the strain point is lowered, so that heat resistance cannot be obtained.
[0029]
However, if the total amount of MgO, CaO, SrO, BaO and ZnO is less than 5%, the viscosity of the glass at a high temperature increases, the meltability deteriorates, and the glass tends to devitrify. Further, the density of the glass becomes high and it becomes difficult to make it 2.6 g / cm 3 or less.
[0030]
ZrO 2 is a component that improves the chemical resistance of glass, particularly acid resistance, and lowers the viscosity at high temperature to improve the meltability, and its content is 0 to 5%, preferably 0 to 1.8%. It is. If it exceeds 5%, the devitrification temperature rises and the devitrified foreign matter of zircon tends to precipitate.
[0031]
TiO 2 is a component that improves chemical resistance, particularly buffered hydrofluoric acid resistance, lowers high-temperature viscosity, and improves meltability, and its content is 0 to 5%. If it exceeds 5%, the glass is colored, and the transmittance is lowered, which is not preferable as a glass substrate for display.
[0032]
In the present invention, in addition to the above components, other components can be added as long as the characteristics are not impaired. For example, As 2 O 3 , Sb 2 O 3 , F 2 , Cl 2 can be used as a fining agent. It is possible to add components such as SO 3 .
[0033]
However, PbO and P 2 O 5 which are generally used as fluxes remarkably deteriorate the chemical resistance of the glass, so addition should be avoided in the present invention. In particular, PbO is volatilized from the surface of the melt during melting. However, it is not preferable because it may contaminate the environment.
[0034]
【Example】
Hereinafter, the alkali-free glass substrate of the present invention will be described in detail based on examples.
[0035]
Tables 1 and 2 show the glass of the example (sample Nos. 1 to 10) and the glass of the comparative example (samples No. 11 to 13).
[0036]
[Table 1]
[Table 2]
Each sample in the table was prepared as follows. First, glass raw materials were prepared so as to have the composition shown in the table, put into a platinum crucible, melted at 1580 ° C. for 24 hours, poured out onto a carbon plate, and formed into a plate shape. Subsequently, both surfaces of these plate glasses were optically polished to obtain glass substrates.
[0039]
As is apparent from the table, Examples No. Each of the samples 1 to 10 has a density of 2.59 g / cm 3 or less, a strain point of 664 ° C. or higher, a devitrification temperature of 1118 ° C. or lower, and a temperature corresponding to 10 2.5 poise of 1630 ° C. or lower. Also had good properties. These samples were also excellent in hydrochloric acid resistance and buffered hydrofluoric acid resistance.
[0040]
On the other hand, No. which is a comparative example. The sample No. 11 has a higher density than that of the example, and is considered to have a large weight. Moreover, since the strain point is low, the heat resistance is poor and the hydrochloric acid resistance is also poor. No. The sample No. 12 was higher in density and lower in strain point than the examples, so it was inferior in heat resistance, and was also poor in hydrochloric acid resistance and buffered hydrofluoric acid resistance. Furthermore, no. The sample No. 13 was inferior in meltability because of its significantly higher devitrification temperature and higher temperature viscosity than in the examples, and also had poor hydrochloric acid resistance.
[0041]
The density is measured by the well-known Archimedes method. Further, the strain point is measured based on the method of ASTM C336-71, and the devitrification temperature is prepared from a glass powder having a particle size of 300 to 500 μm from each sample. And obtained by observation of devitrification after being held for 24 hours.
[0042]
The 10 2.5 poise temperature indicates a temperature corresponding to 10 2.5 poise, which is a high-temperature viscosity, and the lower this temperature, the better the melt moldability.
[0043]
Furthermore, the hydrochloric acid resistance was evaluated by observing the surface state of the glass substrate after each sample was immersed in a 10% by weight hydrochloric acid aqueous solution maintained at 80 ° C. for 24 hours. The case where the surface of the glass substrate was discolored was indicated by ×, and the case where there was no change was indicated by ○.
[0044]
Buffered hydrofluoric acid resistance was determined by immersing each sample in buffered hydrofluoric acid composed of 38.7% by weight ammonium fluoride and 1.6% by weight hydrofluoric acid maintained at 20 ° C. for 30 minutes. Evaluation was made by observing the surface condition. The case where the surface of the glass substrate was clouded was indicated by ×, and the case where there was no change was indicated by ○.
[0045]
【The invention's effect】
As described above, the alkali-free glass substrate of the present invention does not substantially contain an alkali metal oxide, is excellent in heat resistance, chemical resistance, melt moldability, and has low density, and therefore particularly requires weight reduction. It is suitable as a glass substrate used for a TFT type active matrix liquid crystal display.
Claims (2)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21810395A JP3666610B2 (en) | 1995-08-02 | 1995-08-02 | Alkali-free glass substrate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21810395A JP3666610B2 (en) | 1995-08-02 | 1995-08-02 | Alkali-free glass substrate |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0948632A JPH0948632A (en) | 1997-02-18 |
| JP3666610B2 true JP3666610B2 (en) | 2005-06-29 |
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|---|---|---|---|
| JP21810395A Expired - Fee Related JP3666610B2 (en) | 1995-08-02 | 1995-08-02 | Alkali-free glass substrate |
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| JP (1) | JP3666610B2 (en) |
Families Citing this family (29)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3800657B2 (en) * | 1996-03-28 | 2006-07-26 | 旭硝子株式会社 | Alkali-free glass and flat display panel |
| JP3988209B2 (en) * | 1996-06-03 | 2007-10-10 | 旭硝子株式会社 | Alkali-free glass and liquid crystal display panel |
| US6060168A (en) | 1996-12-17 | 2000-05-09 | Corning Incorporated | Glasses for display panels and photovoltaic devices |
| KR19990012860A (en) * | 1997-07-31 | 1999-02-25 | 암라인/립퍼 | Alkali-free borosilicate glass and its use / 1 |
| KR19990012861A (en) * | 1997-07-31 | 1999-02-25 | 암라인/립퍼 | Alkali-free alumino borosilicate glass and its use / 2 |
| DE19739912C1 (en) * | 1997-09-11 | 1998-12-10 | Schott Glas | New alkali-free aluminoborosilicate glass |
| JPH11292563A (en) * | 1998-04-03 | 1999-10-26 | Nippon Electric Glass Co Ltd | Alkali-free glass substrate |
| DE19916296C1 (en) * | 1999-04-12 | 2001-01-18 | Schott Glas | Alkali-free aluminoborosilicate glass and its use |
| KR100623805B1 (en) * | 1999-06-29 | 2006-09-18 | 호야 가부시키가이샤 | Glass Substrates and Glass Compositions for Use in Liquid Crystal Panels |
| DE19934072C2 (en) * | 1999-07-23 | 2001-06-13 | Schott Glas | Alkali-free aluminoborosilicate glass, its uses and processes for its manufacture |
| DE19939789A1 (en) * | 1999-08-21 | 2001-02-22 | Schott Glas | Alkali-free aluminoborosilicate glasses and their uses |
| DE19942259C1 (en) | 1999-09-04 | 2001-05-17 | Schott Glas | Alkaline earth aluminum borosilicate glass and its uses |
| DE10000838B4 (en) * | 2000-01-12 | 2005-03-17 | Schott Ag | Alkali-free aluminoborosilicate glass and its uses |
| DE10000839C1 (en) | 2000-01-12 | 2001-05-10 | Schott Glas | Alkali-free aluminoborosilicate glass and its uses |
| DE10000836B4 (en) * | 2000-01-12 | 2005-03-17 | Schott Ag | Alkali-free aluminoborosilicate glass and its uses |
| DE10000837C1 (en) * | 2000-01-12 | 2001-05-31 | Schott Glas | Alkali-free alumino-borosilicate glass used as substrate glass in thin film transistor displays and thin layer solar cells contains oxides of silicon, boron, aluminum, magnesium, strontium, and barium |
| DE10064804C2 (en) * | 2000-12-22 | 2003-03-20 | Schott Glas | Alkali-free aluminoborosilicate glasses and their use |
| DE10114581C2 (en) * | 2001-03-24 | 2003-03-27 | Schott Glas | Alkali-free aluminoborosilicate glass and uses |
| JP4013913B2 (en) | 2004-04-05 | 2007-11-28 | 日本板硝子株式会社 | Lead-free glass composition for refractive index distribution type lens, refractive index distribution type lens, method of manufacturing refractive index distribution type lens, optical product and optical apparatus |
| KR101399745B1 (en) | 2006-02-10 | 2014-05-26 | 코닝 인코포레이티드 | Glass composition having high thermal and chemical stability and methods of making thereof |
| JP4457410B2 (en) * | 2006-09-21 | 2010-04-28 | 日本電気硝子株式会社 | Alkali-free glass substrate |
| DE102008005857A1 (en) * | 2008-01-17 | 2009-07-23 | Schott Ag | Alkali-free glass |
| US8713967B2 (en) | 2008-11-21 | 2014-05-06 | Corning Incorporated | Stable glass sheet and method for making same |
| TWI478889B (en) | 2010-10-06 | 2015-04-01 | Corning Inc | Alkali-free glass compositions having high thermal and chemical stability |
| WO2012077609A1 (en) * | 2010-12-07 | 2012-06-14 | 旭硝子株式会社 | Alkali free glass and method for producing alkali free glass |
| WO2013047586A1 (en) * | 2011-09-30 | 2013-04-04 | ＡｖａｎＳｔｒａｔｅ株式会社 | Glass substrate for flat panel display |
| FR3008695B1 (en) * | 2013-07-16 | 2021-01-29 | Corning Inc | ALUMINOSILICATE GLASS THE COMPOSITION OF WHICH IS FREE OF ALKALINE METALS, SUITABLE AS A SUBSTRATE FOR BAKING PLATES FOR INDUCTION HEATING |
| CN104276755B (en) * | 2013-10-31 | 2017-02-15 | 东旭集团有限公司 | Alkali-free aluminium borosilicate glass with high chemical durability |
| TWI792109B (en) * | 2020-12-02 | 2023-02-11 | 台灣玻璃工業股份有限公司 | Glass composition with low thermal expansion coefficient and glass fiber thereof |
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