JP2004146355A - Forming method of transparent conductive film, and base material having transparent conductive film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a forming method of a transparent conductive film having a low resistance value, not deteriorating a specific resistance value even if the film is left under high moisture and a high temperature, with high hardness and an excellent etching property, and to provide a base material having the transparent conductive film with good quality and high performance manufactured by above method. <P>SOLUTION: In the forming method of a thin film, gas including transparent conductive film forming gas is supplied into a discharge space under atmospheric pressure or pressure close thereto, and the gas is excited by impressing a high frequency electric field, and a thin film is deposited on the base material by exposing the base material in the excited gas. The high frequency electric field is formed by superposing first and second high frequency electric fields. The frequency ω<SB>2</SB>of the 2nd electric field is higher than the frequency ω<SB>1</SB>of the 1st electric field, and the strength of the first high frequency electric field V<SB>1</SB>, the strength of the second high frequency electric field V<SB>2</SB>and the strength of a discharge starting electric field IV fulfill a relation of V<SB>I</SB>≥IV>V<SB>2</SB>or V<SB>1</SB>>IV≥V<SB>2</SB>. <P>COPYRIGHT: (C)2004,JPO

Description

等の市販のものを挙げることが出来、何れも使用することが出来る。なお、＊印はハイデン研究所インパルス高周波電源（連続モードで１００ｋＨｚ）である。
【０１５８】
また、第２電源（高周波電源）としては、

等の市販のものを挙げることが出来、何れも好ましく使用出来る。
【０１５９】
本発明においては、このような電界を発生させて、均一なグロー放電状態を保つことが出来る電極をプラズマ放電処理装置に採用する必要がある。
【０１６０】
本発明において、対向する電極間に印加する電力は、第２電極（第２の高周波電界）に１Ｗ／ｃｍ^２以上の電力（出力密度）を供給し、放電ガスを励起してプラズマを発生させ、エネルギーを透明導電膜形成ガスに与え透明導電膜を形成させることが好ましい。供給する電力の上限値としては、好ましくは５０Ｗ／ｃｍ^２以下、より好ましくは２０Ｗ／ｃｍ^２以下である。下限値は、好ましくは１．２Ｗ／ｃｍ^２以上である。なお、放電面積（ｃｍ^２）は、電極において放電が起こる範囲の面積のことを指す。
【０１６１】
また、第１電極（第１の高周波電界）にも、１Ｗ／ｃｍ^２以上の電力（出力密度）を供給することにより、第２の高周波電界の均一性を維持したまま、出力密度を向上させることが出来る。これにより、更なる均一高密度プラズマを生成出来、更なる製膜速度の向上と膜質の向上が両立出来る。好ましくは５Ｗ／ｃｍ^２以上である。第１電極に供給する電力の上限値は、好ましくは５０Ｗ／ｃｍ^２である。
【０１６２】
ここで電圧の印加法に関しては、連続モードと呼ばれる連続サイン波状の連続発振モードと、パルスモードと呼ばれるＯＮ／ＯＦＦを断続的に行う断続発振モードのどちらを採用してもよいが、少なくとも第２電極側は連続サイン波の方がより緻密で良質な膜が得られるので好ましい。
【０１６３】
このような大気圧プラズマによる透明導電膜形成法に使用する電極は、構造的にも、性能的にも過酷な条件に耐えられるものでなければならない。このような電極としては、金属質母材上に誘電体を被覆したものであることが好ましい。
【０１６４】
本発明に使用する誘電体被覆電極においては、様々な金属質母材と誘電体との間に特性が合うものが好ましく、その一つの特性として、金属質母材と誘電体との線熱膨張係数の差が１０×１０^−６／℃以下となる組み合わせのものである。好ましくは８×１０^−６／℃以下、更に好ましくは５×１０^−６／℃以下、更に好ましくは２×１０^−６／℃以下である。なお、線熱膨張係数とは、周知の材料特有の物性値である。
【０１６５】
線熱膨張係数の差が、この範囲にある導電性の金属質母材と誘電体との組み合わせとしては、
▲１▼金属質母材が純チタンまたはチタン合金で、誘電体がセラミックス溶射被膜
▲２▼金属質母材が純チタンまたはチタン合金で、誘電体がガラスライニング
▲３▼金属質母材がステンレススティールで、誘電体がセラミックス溶射被膜
▲４▼金属質母材がステンレススティールで、誘電体がガラスライニング
▲５▼金属質母材がセラミックスおよび鉄の複合材料で、誘電体がセラミックス溶射被膜
▲６▼金属質母材がセラミックスおよび鉄の複合材料で、誘電体がガラスライニング
▲７▼金属質母材がセラミックスおよびアルミの複合材料で、誘電体がセラミックス溶射皮膜
▲８▼金属質母材がセラミックスおよびアルミの複合材料で、誘電体がガラスライニング
等がある。線熱膨張係数の差という観点では、上記▲１▼または▲２▼および▲５▼〜▲８▼が好ましく、特に▲１▼が好ましい。
【０１６６】
本発明において、金属質母材は、上記の特性からはチタンまたはチタン合金が特に有用である。金属質母材をチタンまたはチタン合金とすることにより、誘電体を上記とすることにより、使用中の電極の劣化、特にひび割れ、剥がれ、脱落等がなく、過酷な条件での長時間の使用に耐えることが出来る。
【０１６７】
本発明に有用な電極の金属質母材は、チタンを７０質量％以上含有するチタン合金またはチタン金属である。本発明において、チタン合金またはチタン金属中のチタンの含有量は、７０質量％以上であれば、問題なく使用出来るが、好ましくは８０質量％以上のチタンを含有しているものが好ましい。本発明に有用なチタン合金またはチタン金属は、工業用純チタン、耐食性チタン、高力チタン等として一般に使用されているものを用いることが出来る。工業用純チタンとしては、ＴＩＡ、ＴＩＢ、ＴＩＣ、ＴＩＤ等を挙げることが出来、何れも鉄原子、炭素原子、窒素原子、酸素原子、水素原子等を極僅か含有しているもので、チタンの含有量としては、９９質量％以上を有している。耐食性チタン合金としては、Ｔ１５ＰＢを好ましく用いることが出来、上記含有原子の他に鉛を含有しており、チタン含有量としては、９８質量％以上である。また、チタン合金としては、鉛を除く上記の原子の他に、アルミニウムを含有し、その他バナジウムや錫を含有しているＴ６４、Ｔ３２５、Ｔ５２５、ＴＡ３等を好ましく用いることが出来、これらのチタン含有量としては、８５質量％以上を含有しているものである。これらのチタン合金またはチタン金属はステンレススティール、例えばＡＩＳＩ３１６に比べて、熱膨張係数が１／２程度小さく、金属質母材としてチタン合金またはチタン金属の上に施された後述の誘電体との組み合わせがよく、高温、長時間での使用に耐えることが出来る。
【０１６８】
一方、誘電体の求められる特性としては、具体的には、比誘電率が６〜４５の無機化合物であることが好ましく、また、このような誘電体としては、アルミナ、窒化珪素等のセラミックス、あるいは、ケイ酸塩系ガラス、ホウ酸塩系ガラス等のガラスライニング材等がある。この中では、後述のセラミックスを溶射したものやガラスライニングにより設けたものが好ましい。特にアルミナを溶射して設けた誘電体が好ましい。
【０１６９】
または、上述のような大電力に耐える仕様の一つとして、誘電体の空隙率が１０体積％以下、好ましくは８体積％以下であることで、好ましくは０体積％を越えて５体積％以下である。なお、誘電体の空隙率は、ＢＥＴ吸着法や水銀ポロシメーターにより測定することが出来る。後述の実施例においては、島津製作所製の水銀ポロシメーターにより金属質母材に被覆された誘電体の破片を用い、空隙率を測定する。誘電体が、低い空隙率を有することにより、高耐久性が達成される。このような空隙を有しつつも空隙率が低い誘電体としては、後述の大気圧プラズマ溶射法等による高密度、高密着のセラミックス溶射被膜等を挙げることが出来る。更に空隙率を下げるためには、封孔処理を行うことが好ましい。
【０１７０】
上記、大気圧プラズマ溶射法は、セラミックス等の微粉末、ワイヤ等をプラズマ熱源中に投入し、溶融または半溶融状態の微粒子として被覆対象の金属質母材に吹き付け、皮膜を形成させる技術である。プラズマ熱源とは、分子ガスを高温にし、原子に解離させ、更にエネルギーを与えて電子を放出させた高温のプラズマガスである。このプラズマガスの噴射速度は大きく、従来のアーク溶射やフレーム溶射に比べて、溶射材料が高速で金属質母材に衝突するため、密着強度が高く、高密度な被膜を得ることが出来る。詳しくは、特開２０００−３０１６５５号に記載の高温被曝部材に熱遮蔽皮膜を形成する溶射方法を参照することが出来る。この方法により、上記のような被覆する誘電体（セラミック溶射膜）の空隙率にすることが出来る。
【０１７１】
また、大電力に耐える別の好ましい仕様としては、誘電体の厚みが数ミリ、より好ましくは０．５〜２ｍｍであることである。この膜厚変動は、５％以下であることが望ましく、好ましくは３％以下、更に好ましくは１％以下である。
【０１７２】
誘電体の空隙率をより低減させるためには、上記のようにセラミックス等の溶射膜に、更に、無機化合物で封孔処理を行うことが好ましい。前記無機化合物としては、金属酸化物が好ましく、この中では特に酸化ケイ素（ＳｉＯ_ｘ）を主成分として含有するものが好ましい。
【０１７３】
封孔処理の無機化合物は、ゾルゲル反応により硬化して形成したものであることが好ましい。封孔処理の無機化合物が金属酸化物を主成分とするものである場合には、金属アルコキシド等を封孔液として前記セラミック溶射膜上に塗布し、ゾルゲル反応により硬化する。無機化合物がシリカを主成分とするものの場合には、アルコキシシランを封孔液として用いることが好ましい。
【０１７４】
ここでゾルゲル反応の促進には、エネルギー処理を用いることが好ましい。エネルギー処理としては、熱硬化（好ましくは２００℃以下）や、紫外線照射などがある。更に封孔処理の仕方として、封孔液を希釈し、コーティングと硬化を逐次で数回繰り返すと、よりいっそう無機質化が向上し、劣化の無い緻密な電極が出来る。
【０１７５】
本発明に係る誘電体被覆電極の金属アルコキシド等を封孔液として、セラミックス溶射膜にコーティングした後、ゾルゲル反応で硬化する封孔処理を行う場合、硬化した後の金属酸化物の含有量は６０モル％以上であることが好ましい。封孔液の金属アルコキシドとしてアルコキシシランを用いた場合には、硬化後のＳｉＯ_ｘ（ｘは２以下）含有量が６０モル％以上であることが好ましい。硬化後のＳｉＯ_ｘ含有量は、ＸＰＳにより誘電体層の断層を分析することにより測定する。
【０１７６】
本発明の透明導電膜形成方法に係る電極においては、電極の少なくとも基材と接する側のＪＩＳ　Ｂ　０６０１で規定される表面粗さの最大高さ（Ｒｍａｘ）が１０μｍ以下になるように調整することが、本発明に記載の効果を得る観点から好ましいが、更に好ましくは、表面粗さの最大値が８μｍ以下であり、特に好ましくは、７μｍ以下に調整することである。このように誘電体被覆電極の誘電体表面を研磨仕上げする等の方法により、誘電体の厚み及び電極間のギャップを一定に保つことが出来、放電状態を安定化出来ること、更に熱収縮差や残留応力による歪やひび割れを無くし、且つ、高精度で、耐久性を大きく向上させることが出来る。誘電体表面の研磨仕上げは、少なくとも基材と接する側の誘電体において行われることが好ましい。更にＪＩＳ　Ｂ　０６０１で規定される中心線平均表面粗さ（Ｒａ）は０．５μｍ以下が好ましく、更に好ましくは０．１μｍ以下である。
【０１７７】
本発明に使用する誘電体被覆電極において、大電力に耐える他の好ましい仕様としては、耐熱温度が１００℃以上であることである。更に好ましくは１２０℃以上、特に好ましくは１５０℃以上である。また上限は５００℃である。なお、耐熱温度とは、絶縁破壊が発生せず、正常に放電出来る状態において耐えられる最も高い温度のことを指す。このような耐熱温度は、上記のセラミックス溶射や、泡混入量の異なる層状のガラスライニングで設けた誘電体を適用したり、下記金属質母材と誘電体の線熱膨張係数の差の範囲内の材料を適宜選択する手段を適宜組み合わせることによって達成可能である。
【０１７８】
次に、本発明の透明導電膜を形成するガスについて説明する。使用するガスは、基本的に放電ガス及び透明導電膜形成ガスを構成成分とするガスである。放電ガスと透明導電膜形成ガスを混合して放電空間または処理空間に供給してもよいし、前述のように別の態様として、別々に供給してもかまわない。別々に供給する場合の放電ガスＧ２と透明導電膜形成ガスＧ１との処理空間における比率Ｇ２：Ｇ１は１００：１〜５：１が好ましい。この時の透明導電膜形成ガスＧ１には不活性ガス（放電ガスと同様なガス）を９９．１体積％、また透明導電膜形成ガスを０．９体積％程度の比率で混合されていることが好ましい。
【０１７９】
放電ガスとは、透明導電膜形成可能なグロー放電を起こすことの出来るガスである。放電ガスとしては、窒素、希ガス、空気、水素ガス、酸素などがあり、これらを単独で放電ガスとして用いても、混合して用いてもかまわない。本発明において、放電ガスとして好ましいのは窒素または窒素と酸素の混合ガスである。放電ガスの５０〜１００体積％が窒素または窒素と酸素の混合ガスであることが好ましい。このとき、窒素と酸素の体積比は窒素が５０〜１００、酸素が０〜５０であることが好ましい。また、窒素または窒素と酸素の混合ガス以外の放電ガスとしては、希ガスを５０体積％未満含有することが好ましい。希ガスとしては、周期表の第１８属元素、具体的には、ヘリウム、ネオン、アルゴン、クリプトン、キセノン、ラドン等を挙げることが出来る。また、放電ガスの量は、放電空間または処理空間に供給する全ガス量に対し、９０〜９９．９体積％含有することが好ましい。
【０１８０】
透明導電膜形成ガスとは、放電ガスからのエネルギーを受け取って、それ自身は励起して活性となり、基材上に化学的に堆積して透明導電膜を形成する原料のことである。
【０１８１】
次に、本発明に使用する透明導電膜形成ガスについて説明する。
本発明に使用する透明導電膜形成ガスとしては、有機金属化合物、ハロゲン金属化合物、金属水素化合物等を挙げることが出来る。
【０１８２】
本発明においては、透明導電膜形成ガスは有機金属化合物を含有していることが好ましく、また有機金属化合物から形成される金属酸化物にドーピングするドーピング用有機金属化合物を加える場合があり、同様な有機金属化合物が使用される。
【０１８３】
本発明に有用な有機金属化合物は下記の一般式（Ｉ）で示すものが好ましい。
一般式（Ｉ）　Ｒ^１ _ｘＭＲ^２ _ｙＲ^３ _ｚ
式中、Ｍは金属、Ｒ^１はアルキル基、Ｒ^２はアルコキシ基、Ｒ^３はβ−ジケトン錯体基、β−ケトカルボン酸エステル錯体基、β−ケトカルボン酸錯体基及びケトオキシ基（ケトオキシ錯体基）から選ばれる基であり、金属Ｍの価数をｍとした場合、ｘ＋ｙ＋ｚ＝ｍであり、ｘ＝０〜ｍであり、ｙ＝０〜ｍ、ｚ＝０〜ｍで、何れも０または正の整数である。Ｒ^１のアルキル基としては、メチル基、エチル基、プロピル基、ブチル基等を挙げることが出来る。Ｒ^２のアルコキシ基としては、例えばメトキシ基、エトキシ基、プロポキシ基、ブトキシ基、３，３，３−トリフルオロプロポキシ基等を挙げることが出来る。またアルキル基の水素原子をフッ素原子に置換したものでもよい。Ｒ^３のβ−ジケトン錯体基、β−ケトカルボン酸エステル錯体基、β−ケトカルボン酸錯体基及びケトオキシ基（ケトオキシ錯体基）から選ばれる基としては、β−ジケトン錯体基として、例えば、２，４−ペンタンジオン（アセチルアセトンあるいはアセトアセトンともいう）、１，１，１，５，５，５−ヘキサメチル−２，４−ペンタンジオン、２，２，６，６−テトラメチル−３，５−ヘプタンジオン、１，１，１−トリフルオロ−２，４−ペンタンジオン等を挙げることが出来、β−ケトカルボン酸エステル錯体基として、例えば、アセト酢酸メチルエステル、アセト酢酸エチルエステル、アセト酢酸プロピルエステル、トリメチルアセト酢酸エチル、トリフルオロアセト酢酸メチル等を挙げることが出来、β−ケトカルボン酸として、例えば、アセト酢酸、トリメチルアセト酢酸等を挙げることが出来、またケトオキシとして、例えば、アセトオキシ基（またはアセトキシ基）、プロピオニルオキシ基、ブチリロキシ基、アクリロイルオキシ基、メタクリロイルオキシ基等を挙げることが出来る。これらの基の炭素原子数は、上記例有機金属示化合物を含んで、１８以下が好ましい。また例示にもあるように直鎖または分岐のもの、また水素原子をフッ素原子に置換したものでもよい。
【０１８４】
本発明において取り扱いの問題から、爆発の危険性の少ない有機金属化合物が好ましく、分子内に少なくとも一つ以上の酸素を有する有機金属化合物が好ましい。このようなものとしてＲ^２、即ちアルコキシ基を少なくとも一つを含有する有機金属化合物、またＲ^３、即ちβ−ジケトン錯体基、β−ケトカルボン酸エステル錯体基、β−ケトカルボン酸錯体基及びケトオキシ基（ケトオキシ錯体基）から選ばれる基を少なくとも一つ有する金属化合物が好ましい。
【０１８５】
本発明に使用し得る有機金属化合物の金属は、特に制限ないが、インジウム（Ｉｎ）、錫（Ｓｎ）、亜鉛（Ｚｎ）、ジルコニウム（Ｚｒ）、アルミニウム（Ａｌ）及びアンチモン（Ｓｂ）、ガリウム（Ｇａ）、ゲルマニウム（Ｇｅ）から選ばれる少なくとも１種の金属が好ましく、インジウム、亜鉛及び錫から選ばれる少なくとも１種の金属が特に好ましい。
【０１８６】
本発明において、上記の好ましい有機金属化合物の例としては、インジウムトリス２，４−ペンタンジオナート（あるいは、トリスアセトアセトナートインジウム）、インジウムトリスヘキサフルオロペンタンジオナート、メチルトリメチルアセトキシインジウム、トリアセトアセトオキシインジウム、トリアセトオキシインジウム、ジエトキシアセトアセトオキシインジウム、インジウムトリイソポロポキシド、ジエトキシインジウム（１，１，１−トリフルオロペンタンジオナート）、トリス（２，２，６，６−テトラメチル−３，５−ヘプタンジオナート）インジウム、エトキシインジウムビスアセトメチルアセタート、ジ（ｎ）ブチルビス（２，４−ペンタンジオナート）錫、ジ（ｎ）ブチルジアセトオキシ錫、ジ（ｔ）ブチルジアセトオキシ錫、テトライソプロポキシ錫、テトラ（ｉ）ブトキシ錫、亜鉛２，４−ペンタンジオナート等を挙げることが出来、何れも好ましく用いることが出来る。
【０１８７】
この中で特に、インジウムトリス２，４−ペンタンジオナート、トリス（２，２，６，６−テトラメチル−３，５−ヘプタンジオナート）インジウム、亜鉛ビス２，４−ペンタンジオナート、ジ（ｎ）ブチルジアセトオキシ錫が好ましい。これらの有機金属化合物は一般に市販（例えば、東京化成工業（株）等から）されている。
【０１８８】
本発明において、該有機金属化合物から形成される透明導電膜の導電性を更に高めるためのドーピング用有機金属化合物またはドーピング用フッ素化合物を混合ガスに含有させることが好ましい。ドーピング用有機金属化合物またはドーピング用フッ素化合物としては、例えば、トリイソプロポキシアルミニウム、ニッケルトリス２，４−ペンタンジオナート、マンガンビス２，４−ペンタンジオナート、ボロンイソプロポキシド、トリ（ｎ）ブトキシアンチモン、トリ（ｎ）ブチルアンチモン、ジ（ｎ）ブチル錫ビス２，４−ペンタンジオナート、ジ（ｎ）ブチルジアセトオキシ錫、ジ（ｔ）ブチルジアセトオキシ錫、テトライソプロポキシ錫、テトラブトキシ錫、テトラブチル錫、亜鉛２，４−ペンタンジオナート、ジプロポキシゲルマニウム、ジ（ｎ）ブチルジアセトオキシゲルマニウム、ゲルマニウムトリス２，４−ペンタンジオナート、ガリウムトリス２，４−ペンタンジオナート、トリプロポキシガリウム、ブチルジアセトオキシガリウム、六フッ化プロピレン、八フッ化シクロブタン、四フッ化メタン等を挙げることが出来る。
【０１８９】
前記透明導電膜を形成するに必要な有機金属化合物と上記ドーピング用の比は、形成する透明導電膜の種類により異なるが、例えば、酸化インジウムに錫をドーピングして得られるＩＴＯ膜においては、Ｉｎ：Ｓｎの原子数比が１００：０．１〜１００：１５の範囲になるように透明導電膜形成ガス量を調整することが必要である。好ましくは、１００：０．５〜１００：１０になるよう調整することが好ましい。酸化錫にフッ素をドーピングして得られる透明導電膜（フッ素ドープ酸化錫膜をＦＴＯ膜という）においては、得られたＦＴＯ膜のＳｎ：Ｆの原子数比が１００：０．０１〜１００：５０の範囲になるよう透明導電膜形成ガスの量比を調整することが好ましい。Ｉｎ_２Ｏ_３−ＺｎＯ透明導電膜においては、Ｉｎ：Ｚｎの原子数比が１００：５０〜１００：５の範囲になるよう透明導電膜形成ガスの量比を調整することが好ましい。Ｉｎ：Ｓｎ、Ｓｎ：Ｆ及びＩｎ：Ｚｎの各原子数比はＸＰＳ測定によって求めることが出来る。
【０１９０】
本発明において、得られる透明導電膜は、例えば、ＳｎＯ_２、Ｉｎ_２Ｏ_３、ＺｎＯの酸化物膜、またはＳｂドープＳｎＯ_２、ＦＴＯ、ＡｌドープＺｎＯ、ＺｎドープＩｎ（ＩＺＯということがある）、ＺｒドープＩｎ、ＩＴＯ等ドーパントによりドーピングされた複合酸化物を挙げることが出来、これらから選ばれる少なくとも一つを主成分とするアモルファス膜が好ましい。またその他にカルコゲナイド、ＬａＢ_６、ＴｉＮ、ＴｉＣ等の非酸化物膜、Ｐｔ、Ａｕ、Ａｇ、Ｃｕ等の金属膜、ＣｄＯ等の透明導電膜を挙げることが出来る。
【０１９１】
上記、有機金属化合物の透明導電膜形成ガスは全ガス中で０．０１〜１０体積％含有されることが好ましく、より好ましくは０．１〜３体積％である。
【０１９２】
本発明で用いるガスには還元ガスを含有させることが好ましい。本発明でいう還元ガスは分子内に酸素を含まない化学的に還元性を有する無機ガスをいう。還元性ガスとしては、水素、硫化水素、メタン等の炭化水素及び水等を挙げることが出来るが、好ましくは水素ガスである。還元性ガスの量は全ガスに対して、０．０００１〜５．０体積％、好ましくは０．００１〜３．０体積％である。還元性ガスを含有させることにより、還元性ガスは透明導電膜を形成するガスに作用し、形成された透明導電膜をより均一に緻密にすることが出来、導電性及びエッチング性能を向上させることが出来る。
【０１９３】
このように透明導電膜形成に直接は関与せずとも、透明導電膜の性質に影響を及ぼすガスを補助ガスまたは添加ガスという。補助ガスには、還元性ガスの他に、酸素、オゾン、過酸化水素、二酸化炭素、一酸化炭素、酸素のような酸化性ガス、メタン、エタン、プロパン、エチレン、プロピレン等の炭化水素ガス、その他透明導電膜形成を促進するようなガスなどがある。補助ガスは全ガス１００体積％に対して０．０００１〜５体積％が好ましく、より好ましくは０．００１〜３体積％である。
【０１９４】
上記形成される金属酸化物または金属複合化合物の透明導電膜の膜厚は、０．１〜１０００ｎｍの範囲が好ましい。
【０１９５】
本発明の透明導電膜を有する物品の製造方法により得られる透明導電膜は、高いキャリア移動度を有する特徴を持つ。よく知られているように透明導電膜の電気伝導率は以下の（１）式で表される。
【０１９６】
σ＝ｎ×ｅ×μ　（１）
ここで、σは電気伝導率、ｎはキャリア密度、ｅは電子の電気量、そしてμはキャリアの移動度である。電気伝導率σを上げるためにはキャリア密度ｎあるいはキャリア移動度μを増大させる必要があるが、キャリア密度ｎを増大させていくと２×１０^２１ｃｍ^−３付近から反射率が大きくなるため透明性が失われる。そのため、電気伝導率σを増大させるためにはキャリア移動度μを増大させる必要がある。本発明の透明導電膜の形成方法によれば条件を最適化することにより、ＤＣマグネトロンスパッタリング法により形成された透明導電膜に近いキャリア移動度μを有する透明導電膜を形成することが可能であることが判明した。
【０１９７】
本発明の透明導電膜の形成方法は高いキャリア移動度μを有するため、ドーピングなしでも比抵抗値として１×１０^−３Ω・ｃｍ以下の比抵抗値の透明導電膜を得ることが出来る。ドーピングを行いキャリア密度ｎを増加させることで更に比抵抗値を下げることが出来る。また、必要に応じて比抵抗値を上げる透明導電膜形成ガスを用いることにより、比抵抗値として１×１０^−２Ω・ｃｍ以上の高比抵抗値の透明導電膜を得ることも出来る。透明導電膜の比抵抗値を調整するために用いる透明導電膜形成ガスとしては、例えば、チタントリイソプロポキシド、テトラメトキシシラン、テトラエトキシシラン、ヘキサメチルジシロキサン等を挙げることが出来る。
【０１９８】
本発明の透明導電膜の形成方法によって得られる透明導電膜は、キャリア密度ｎが、１×１０^１９ｃｍ^−３以上、より好ましい条件下においては、１×１０^２０ｃｍ^−３以上となるが、透明性は低下しない。
【０１９９】
本発明の優れた効果の一つとして、エッチングがある。各種ディスプレイ素子を電極として用いる場合、基板上に回路を描くパターニング工程は必須なものであり、パターニングが容易に行うことが出来るかが工程適性上重要な課題となっている。一般に、パターニングはフォトリソグラフィー法により行われることが多く、導通を必要としない部分はエッチングにより溶解、除去するため、該部分のエッチング液による溶解の速さ及び残渣のないことが重要な課題となっている。エッチング液には、通常、硝酸、塩酸、塩酸と硝酸の混酸、フッ酸、塩化第二鉄水溶液等が用いられ、これらのウェットエッチングする方法が主流である。
【０２００】
透明性導電性透明導電膜として、上記形成された酸化物または複合酸化物の透明導電膜の膜厚は、０．１〜１０００ｎｍの範囲が好ましい。
【０２０１】
本発明の透明導電性フィルムの基材について説明する。
本発明の透明導電性フィルムを形成する基材としては、透明導電膜をその表面に形成出来るものであれば特に限定はない。基材がプラズマ状態の混合ガスに晒され、均一の透明導電膜が形成されるものであれば基材の形態または材質には制限ない。樹脂フィルム、樹脂シート（板）、ガラス板が本発明には適している。
【０２０２】
樹脂フィルムは本発明に係る大気圧プラズマ放電処理装置の電極間または電極の近傍を連続的に移送させて透明導電膜を形成することが出来るので、スパッタリングのような真空系のようなバッチ式でない、大量生産に向き、連続的な生産性の高い生産方式として好適である。
【０２０３】
樹脂フィルム、樹脂シート、樹脂レンズ、樹脂成形物等成形物の材質としては、セルローストリアセテート、セルロースジアセテート、セルロースアセテートプロピオネートまたはセルロースアセテートブチレートのようなセルロースエステル、ポリエチレンテレフタレートやポリエチレンナフタレートのようなポリエステル、ポリエチレンやポリプロピレンのようなポリオレフィン、ポリ塩化ビニリデン、ポリ塩化ビニル、ポリビニルアルコール、エチレンビニルアルコールコポリマー、シンジオタクティックポリスチレン、ポリカーボネート、ノルボルネン樹脂、ポリメチルペンテン、ポリエーテルケトン、ポリイミド、ポリエーテルスルフォン、ポリスルフォン、ポリエーテルイミド、ポリアミド、フッ素樹脂、ポリメチルアクリレート、アクリレートコポリマー等を挙げることが出来る。
【０２０４】
これらの素材は単独であるいは適宜混合されて使用することも出来る。中でもゼオネックスやゼオノア（日本ゼオン（株）製）、非晶質シクロポリオレフィン樹脂フィルムのＡＲＴＯＮ（日本合成ゴム（株）製）、ポリカーボネートフィルムのピュアエース（帝人（株）製）、セルローストリアセテートフィルムのコニカタックＫＣ４ＵＸ、ＫＣ８ＵＸ（コニカ（株）製）などの市販品を好ましく使用することが出来る。更に、ポリカーボネート、ポリアリレート、ポリスルフォン及びポリエーテルスルフォンなどの固有複屈折率の大きい素材であっても、溶液流延製膜、溶融押し出し製膜等の条件、更には縦、横方向に延伸条件等を適宜設定することにより使用することが出来るものを得ることが出来る。
【０２０５】
これらのうち光学的に等方性に近いセルロースエステルフィルムが本発明の透明導電性フィルムに好ましく用いられる。セルロースエステルフィルムとしては、上記のようにセルローストリアセテートフィルム、セルロースアセテートプロピオネートが好ましく用いられるものの一つである。セルローストリアセテートフィルムとしては市販品のコニカタックＫＣ４ＵＸ、ＫＣ８ＵＸ等が有用である。
【０２０６】
これらの樹脂の表面にゼラチン、ポリビニルアルコール、アクリル樹脂、ポリエステル樹脂、セルロースエステル樹脂等を塗設したものも使用出来る。またこれら樹脂フィルムの透明導電膜側に防眩層、クリアハードコート層、防汚層等を設けてもよい。また、必要に応じて接着層、アルカリバリアコート層、ガスバリア層や耐溶剤性層等を設けてもよい。
【０２０７】
ガラス板や樹脂シート（板）が毎葉基材として用いることが出来る。樹脂シート（板）は上記樹脂と同様であるが、ガラス板としてはソーダライムガラス、ホウ珪酸ガラス、超高純度ガラス、クリスタルガラス等を挙げることが出来る。また、本発明に係る基材は、上記の記載に限定されない。フィルム形状のものの膜厚としては１０〜１０００μｍが好ましく、より好ましくは４０〜２００μｍである。またガラス板形状のものの膜厚としては、０．１〜２ｍｍが好ましい。
【０２０８】
【実施例】
次に、本発明を下記実施例でさらに説明するが、無論、本発明の実施態様はこれらに限定されない。
【０２０９】
〔評価項目〕
まず、本実施例において用いる評価項目とその内容および判定の基準について記載する。
【０２１０】
《比抵抗値》
ＪＩＳ−Ｒ−１６３７に従い、四端子法により求めた。なお、測定には三菱化学（株）製ロレスタ−ＧＰ、ＭＣＰ−Ｔ６００を用いた。
【０２１１】
《耐湿、耐熱性（ロバストネス）》
２３℃、５５％ＲＨに放置した試料を恒温器を用いて温度６０℃、９０％ＲＨの条件で２４０時間放置した後、再び２３℃、５５％ＲＨに放置し、加湿、加熱前後の比抵抗値（Ω・ｃｍ）をそれぞれＲ_０及びＲとし、変化率Ｒ／Ｒ_０をロバストネスの指標とした。用いた比抵抗値は、上記比抵抗値と同様の方法で測定した。
【０２１２】
《エッチング》
透明導電膜にパターニングするための下記の組成の３０℃のエッチング液に基材上の透明導電膜を浸漬し、エッチング時間は３０秒、４５秒、６０秒、１２０秒、１８０秒でサンプリングした。続いて水洗、乾燥を行い、乾燥後の試料についてエッチング部と非エッチング部との境界部分の断面を電子顕微鏡により観察し、また膜の除去の具合を目視によって評価した。
【０２１３】
〈エッチング液組成〉
水、濃塩酸及び４０質量％第二塩化鉄溶液を質量比８５：８：７で混合したものをエッチング液とした。
【０２１４】
〈エッチングパターンの評価レベル〉
Ａ：３０秒で透明導電膜が除去出来、エッチングパターンの境界部分が頗る良好なもの
Ｂ：４５秒で透明導電膜が除去出来、エッチングパターンの境界部分が頗る良好なもの
Ｃ：６０秒で透明導電膜は除去出来、エッチングパターンの境界部分が頗る良好なもの
Ｄ：１２０秒で透明導電膜は除去出来たが、エッチングパターンの境界部分があまり良好でない
Ｅ：１８０秒を超しても透明導電膜が若干残っている部分があり、エッチングパターンの境界部分がギザギザ（凸凹）していた
Ｆ：１８０秒を超しても透明導電膜が島状に残っている
《鉛筆硬度試験》
ＪＩＳ　Ｋ５２００に記載の鉛筆硬度測定に準じて透明導電膜を有する物品の表面の硬度を測定、評価した。
【０２１５】
実施例１
図１に示したと同様な構造を有する大気圧プラズマ放電処理装置を使用し、基材フィルムの上にＩＴＯ膜を形成した。
【０２１６】
〔電極の作製〕
前述の図１のプラズマ放電処理装置において、誘電体で被覆したロール電極及び同様に誘電体を被覆した複数の角筒型電極のセットを以下のように作製した。
【０２１７】
第１電極となるロール電極は、ロール径（下記）、ロール円筒長さ５００ｍｍ、肉厚１０ｍｍの円筒冷却水による冷却手段を有するチタン合金Ｔ６４製ジャケットロール金属質母材（図２参照）に対して、大気圧プラズマ法により高密度、高密着性のアルミナ溶射膜を被覆し、ロール径１０００ｍｍとなるようにした。その後、テトラメトキシシランを酢酸エチルで希釈した溶液を塗布乾燥後、紫外線照射により硬化させ封孔処理を行った。このようにして被覆した誘電体表面を研磨し、平滑にして、Ｒｍａｘが５μｍとなるように加工した。最終的な誘電体の空隙率は５体積％であった。この時の誘電体層のＳｉＯ_Ｘ含有率は７５ｍｏｌ％であった。また、最終的な誘電体の膜厚は１ｍｍ、誘電体の比誘電率は１０であった。更に導電性の金属質母材と誘電体の線熱膨張係数の差は、１．６×１０^−６／℃であり、また耐熱温度は２５０℃であった。
【０２１８】
一方、第２電極の角筒型電極は、一辺が４０ｍｍ弱で、長さが５００ｍｍ、肉厚７ｍｍの角筒型のチタン合金Ｔ６４の金属母材（図３の如く中空）に対し、上記同様の誘電体を同条件にて被覆し、一辺を４０ｍｍとなるようにし、これを３０本用意した。これらの角筒型電極の誘電体については上記ロール電極のものと、誘電体表面のＲｍａｘ、誘電体層のＳｉＯ_ｘ含有率、また誘電体の膜厚と比誘電率、金属質母材と誘電体の線熱膨張係数の差、更に電極の耐熱温度は、第１電極とほぼ同じ物性値に仕上がった。
【０２１９】
この角筒型電極をロール回転電極のまわりに、対向電極間隙を１ｍｍとして２５本配置した。角筒型固定電極群の放電総面積は、５０ｃｍ（幅手方向の長さ）×４ｃｍ（搬送方向の長さ）×３０本（電極の数）＝６０００ｃｍ^２であった。
【０２２０】
〔大気圧プラズマ放電処理装置〕
上記角筒型固定電極群３６とロール回転電極３５とで対向電極を構成する図１に示した大気圧プラズマ放電処理装置を使用した。対向電極の間隙を１ｍｍとして、ロール回転電極３５の円と同心円上に角筒型固定電極３６を等間隔に配置した。ロール回転電極３５を第１電極とし、第１電源４１と結線し、またその間に第１フィルター４３を配置しそれぞれをアースに接地した。角筒型固定電極群３６を第２電極とし、それぞれの角筒型電極を結線し第２電源に結び、その間に第２フィルター４４を設置してそれぞれをアースに接地した。第１電源及び第２電源は、高周波電界と放電開始電界との関係に適したものを設置した。
【０２２１】
〔透明導電膜を有するフィルムの作製〕
第１電源４１及び第２電源４２は、表１に示したものを選択して使用した。両電極を８０℃になるように調節保温した。表１に示したように、基材Ｆとして、厚さ１００μｍのＡＲＴＯＮフィルム（非晶質シクロポリオレフィン樹脂フィルム、ＪＳＲ社製）を使用した。放電空間３２の圧力を１０３ｋＰａとし、下記組成の混合ガスＭＧを放電空間３２に満たし、表１に示した高周波電界を印加し、第１電極の出力密度を７Ｗ／ｃｍ^２、第２電極の出力密度を７Ｗ／ｃｍ^２として放電を行って、基材Ｆフィルムの上に膜厚８０ｎｍのＩＴＯ膜を形成した。その際、電源・電極の条件を表１に記載する如く変えて第１電源、第２電源により形成される電界の周波数と電界強度を変化させて、ＩＴＯフィルムの試料Ｎｏ．１〜１７を作製した。この系での窒素ガスの放電開始電界強度は３．７ｋＶ／ｍｍであった。
【０２２２】

試料Ｎｏ．１〜１７について、放電状態を観察し、また、比抵抗値、比抵抗値、ロバストロネス、鉛筆硬度、エッチング特性を評価し、結果を下記表１に示した。
【０２２３】
【表１】

【０２２４】
（結果）
第１及び第２電極の高周波電界強度（Ｖ_１、Ｖ_２）と放電ガスの放電開始電界強度（ＩＶ）関係式が本発明の関係にある試料Ｎｏ．１〜１２については、放電状況もよく、低抵抗値のＩＴＯ膜が形成され、しかも、比抵抗値、ロバストネスも良好であり、鉛筆硬度の全てが良好であった。これに対して、本発明に規定する以外の高周波電界・周波数である試料Ｎｏ．１３〜１７はいずれも、少なくともいずれかの特性に問題があることがわかる。なお、第１、第２の高周波電界が何れも放電開始電界より小さい試料Ｎｏ．１５および１６は、放電が起こらずＩＴＯ膜の形成が出来なかった（粉体状の堆積物となった）。
【０２２５】
実施例２
図７に示した構造を有する大気圧プラズマ放電処理装置を使用し、移動架台上に搭載された基材としてのガラス板の上にＩＴＯ膜を形成した。
【０２２６】
〔電極の作製〕
〈対向電極〉
図７に示したガスを別々に導入出来る２組の固定電極を作製し、対向電極とした。金属母材として、チタン合金Ｔ６４製の長さ５０ｍｍ、幅６００ｍｍ、高さが５０ｍｍの形で肉厚７ｍｍの内部が中空の角筒型のものを２個作製し、第２電極４３６とした。別に、チタン合金Ｔ６４製の長さ５０ｍｍ、幅６００ｍｍ、高さ５０ｍｍの形をした内部が中空で中央部にスリット４２１（長さ４８０ｍｍ）を有するものを作製し、第１電極４３５とした。第２電極４３６と第１電極４３５の面が平行になるように間隙を１ｍｍのスリットとし、このスリットを放電空間４３２とした。第２電極４３６同士はそれぞれ結線で結ばれている。スリット４２１と放電空間４３２の上に図７に示すガス導入口４５２及び４５３を電極の上に接合した。
【０２２７】
〈移動架台〉
絶縁体で覆われている長さ６００ｍｍ、幅６００ｍｍ、厚さ５０ｍｍの平板を用意し、平板の裏側の両側に、移動手段の２本のスクリューねじ軌道に適合したねじを取り付け、スクリューの回転によって移動出来るようにした。
【０２２８】
〔大気圧プラズマ放電処理装置〕
図７に示した対向電極（４３５と４３６）の底面（紙上下側）と移動架台４３３の上のガラス板基材との処理空間４３４の間隙を１．５ｍｍとした。第１電極４３５には表２に示した第１電源４４１を接続し、その間に第１フィルター４４３を設置した。各電源及び各フィルターをそれぞれアースに接地した。
【０２２９】
〔透明導電膜を有するガラス板の作製〕
第１電源４４１及び第２電源４４２は、高周波電界強度と放電開始電界強度との関係がＶ_１＞ＩＶ＞Ｖ_２となるように、表２に示したものを選択して使用した。基材としては、長さ５００ｍｍ、幅４５０ｍｍ、０．５ｍｍ厚のソーダガラス板を使用した。第２電極４３６を３基並べ、第２電極４３６の放電空間４３２及び処理空間４３４を圧力を１０４ＫＰａとし、放電ガスＧ２をガス供給管４５３から放電空間４３２に、また透明導電膜形成ガスＧ１をガス供給管５３２からスリット５２１に導入した。両電極共８０℃になるように温度調節を行った。第１電源４４１及び第２電源４４２から、表２に示す高周波電界を印加し、第１電極の出力密度を７Ｗ／ｃｍ^２、第２電極の出力密度を７Ｗ／ｃｍ^２として放電を行い、放電ガスを放電空間４３２において励起してジェット状に吹き出させ、一方のスリット４２１からは透明導電膜形成ガスを処理空間に放出して混合し、プラズマ状態の放電ガスからエネルギーを受けて透明導電膜形成ガスを励起しプラズマ状態とした。該プラズマ状態の透明導電膜形成ガスＧ°に基材ガラス板Ｆを晒し、移動架台を処理空間４３４中を膜厚８０ｎｍになるまで往復させてＩＴＯ膜を基材ガラス板上に形成し、ＩＴＯ膜を有するガラス板を作製し、試料Ｎｏ．１８〜２１とした。なお、窒素と酸素の混合放電ガスの放電開始電界強度は３．８ｋＶ／ｍｍであった。
【０２３０】
透明導電膜形成ガスＧ１と放電ガスＧ２との比１：１０として処理空間に導入した。
【０２３１】

試料Ｎｏ．２２の作製
第１電源及び第２電源共にＢ１とし（Ｖ_１＝Ｖ_２＜ＩＶ）、また第１フィルター及び第２フィルター共に１０μＨのコイルを接続、設置した他は、試料Ｎｏ．１８と同様に行い、試料Ｎｏ．２２とした。なお、試料Ｎｏ．２２は膜を形成せず、粉体状の堆積物となった。
【０２３２】
試料Ｎｏ．２３、２４の作製
図７の第２電極４６３６から第２電源４４２と第２フィルター４４４を取り外しアースの接地のみとし、表２に示す第１電源を使用した以外は試料Ｎｏ．１８と同様に行い、試料Ｎｏ．２３、２４とした。なお、試料Ｎｏ．２３は膜を形成せず、粉体状の堆積物となった。
【０２３３】
試料Ｎｏ．１８〜２４について、放電状況を確認し、比抵抗値、ロバストネス、鉛筆硬度、鉛筆硬度の評価を行い、結果を下記表２に示した。
【０２３４】
【表２】

【０２３５】
（結果）
放電ガスとして窒素と酸素の混合ガスを使用し、本発明に適した第１電源の周波数と第１フィルター、及び第２電源の周波数と第２フィルターを設置してＩＴＯ膜を形成した試料Ｎｏ．１８〜２１は、放電は正常に行われ、ＩＴＯ膜も正常に形成され、低抵抗値のＩＴＯ膜が形成され、しかも、比抵抗値のロバストネスも良好であり、鉛筆硬度の全てが良好であった。これに対して、試料Ｎｏ．２２（比較）では、第１電源と第２電源の周波数に対し、放電が発生せず、ＩＴＯ膜が形成されず、粉体状の堆積物となっていた。試料Ｎｏ．２３及び２４（比較）は、対向電極がアース電極としたもので、試料Ｎｏ．２３では、放電開始電界強度より低い高周波電界強度で印加したが、放電せず、その結果ＩＴＯ膜が形成されなかった。また試料Ｎｏ．２４では、放電開始電界強度より高い電界強度で印加したが、放電はするものの、良好なＩＴＯ膜の形成が出来ず、該ＩＴＯ膜の比抵抗値も高く、しかも、比抵抗値のロバストネスが不良であり、鉛筆硬度も劣っていた。
【０２３６】
実施例３
図８に記載した構造を有する大気圧プラズマ放電処理装置を用い、ガラス板基材の上にＩＴＯ膜を形成し、酸化性ガス処理室を用いて酸化性ガスで処理し、これらＩＴＯ膜形成と酸化性ガス処理を５回繰り返し、ＩＴＯ膜を有するガラス板を作製した。
【０２３７】
〔電極の作製〕
〈固定電極〉
実施例１で使用したのと同様な誘電体被覆した角筒型電極を２本１組として、２本を平行にして１．５ｍｍの幅のスリットを挟んで接合し、１個の固定電極５３６とした。この２本１組の固定電極５３６を３組用意した。
【０２３８】
〈移動架台電極〉
長さ６００ｍｍ、幅６００ｍｍ、厚さ５０ｍｍ、肉厚７ｍｍの中空チタン合金Ｔ６４の平板を用意し、実施例１あるいは実施例２の金属母材に誘電体を被覆、研磨したのと同様にして、対向電極となる面に誘電体を被覆し、該誘電体被覆は同様な性質を有していた。平板の裏側の両側に、移動手段の２本のスクリューねじ軌道に適合したねじを取り付け、スクリューの回転によって移動出来るようにし、移動架台電極５３５とした。
【０２３９】
〔酸化性ガス処理室〕
ゲート５１９を有する酸化性ガス処理室５６０には、移動架台電極５３５が移動出来る移動手段の２本のスクリューねじ軌道が設置されている。移動架台が酸化性ガス処理室に入った後に、酸化性ガスの導入口から下記酸化性ガスを導入して満たすようになっている。
【０２４０】
〔大気圧プラズマ放電処理装置〕
上記で作製した固定電極５３６をを同一平面上に３基並べて（図８は１基だけ示してあるが）設置し、３個の固定電極５３６と移動架台電極５３５とで構成する対向電極間（放電空間）５３２を１．５ｍｍとした。移動架台電極（第１電極）５３５には表３に示した第１電源５４１を接続し、その間に第１フィルター５４３を設置した。各電源及び各フィルターをそれぞれアースに接地した。
【０２４１】
〔透明導電膜を有するガラス板の作製〕
第１電源５４１及び第２電源５４２は、高周波電界強度と放電開始電界強度との関係がＶ_１＞ＩＶ＞Ｖ_２となるように、表３に示したものを選択して使用した。基材としては、長さ５００ｍｍ、幅４５０ｍｍ、０．５ｍｍ厚のソーダガラス板を使用した。３基の固定電極５３６と移動架台電極５３５との間の放電空間５３２の圧力を１０４ＫＰａとし、下記透明導電膜形成ガスＭＧを、ＩＴＯ膜形成用混合ガスＭＧ、ＩＺＯ膜形成用混合ガスＭＧ及びＦＴＯ膜形成用混合ガスＭＧとして、それぞれガス供給管５５２導入し、下記の高周波電界を印加して、ＩＴＯ膜、ＩＺＯ膜及びＦＴＯ膜をそれぞれ形成した。電極共８０℃になるように温度調節を行った。第１電源５４１及び第２電源５４２から、表３に示す高周波電界を印加し、第１電極の出力密度を７Ｗ／ｃｍ^２、第２電極の出力密度を７Ｗ／ｃｍ^２として放電を発生させ、プラズマ状態の混合ガスを放電空間５２１からジェット状に吹き出させ、処理空間５３２において、プラズマ状態の透明導電膜形成ガスＧ°に、基材ガラス板Ｆを晒し、１回透明導電膜が形成するごとに移動架台を酸化性ガス処理室に移し、下記酸化性ガスに５分間晒した。この操作を、膜厚１００ｎｍになるまでそれぞれ繰り返しＩＴＯ膜、ＩＺＯ膜及びＦＴＯ膜を有するガラス板基材をそれぞれ作製し、試料Ｎｏ．２５〜３４とした。なお、この系での窒素ガスの放電開始電界強度は３．７ｋＶ／ｍｍであった。
【０２４２】

試料Ｎｏ．３５〜４１の作製
表３に示した第１電源と第２電源の組合せ（高周波電界、Ｖ_１＝Ｖ_２＞ＩＶ、Ｖ_１＝Ｖ_２＜ＩＶ）、第２電源不使用等の条件にて試料作製を行い、１００ｎｍのＩＴＯ膜、ＩＺＯ膜、ＦＴＯ膜をガラス板基材上に形成して、試料Ｎｏ．３５〜４１とした。なお、試料Ｎｏ．３６、３８及び４１は膜を形成せず、粉体状の堆積物となった。
【０２４３】
試料Ｎｏ．２５〜４１について、放電状態を観察し、また、比抵抗値、比抵抗値のロバストロネス、鉛筆硬度、エッチング特性を評価し、結果を下記表３に示した。
【０２４４】
【表３】

【０２４５】
（結果）
本発明に適合した周波数及び電界強度としてプラズマ放電処理してＩＴＯ膜を形成し、且つ透明導電膜形成後酸化性ガス処理を行うことによって、膜が緻密で、低抵抗で、ロバストネスも優れ、良好なエッチング特性を合わせ持ったＩＴＯ膜、ＩＺＯ膜ＦＴＯ膜を形成することが出来た（試料Ｎｏ．２５〜３４）。これに対して印加した高周波電界強度と放電開始電界強度との関係がＶ_１＝Ｖ_２＞ＩＶの試料３５、３７及び４０は放電は起こるものの、比抵抗値が高くロバストネスが劣り、硬度も低くエッチング特性も悪いＩＴＯ膜、ＩＺＯ膜及びＦＴＯ膜しか得られなかった。またＩＶ＞Ｖ_１＝Ｖ_２の試料Ｎｏ．３８は、放電が起こらず、膜の形成が出来なかった。第２電源を使用しなかった試料３１は放電は起こるものの、ＩＺＯ膜の形成が出来ず、また試料Ｎｏ．３６、４１は放電が起こらず、ＦＴＯ膜の形成が出来なかった。
【０２４６】
【発明の効果】
本発明により、高密度プラズマが達成出来、低抵抗値を有し、高湿高温条件下に放置しても比抵抗値が劣化せず、硬度が高く、エッチング性能に優れた良質な透明導電膜の形成方法を提供し、これにより製造される良質で高性能な透明導電膜を有する基材を安価に提供することが出来る。
【図面の簡単な説明】
【図１】本発明に有用な大気圧プラズマ放電処理装置の一例を示す概略図である。
【図２】図１に示したロール回転電極の導電性の金属質母材とその上に被覆されている誘電体の構造の一例を示す斜視図である。
【図３】角筒型電極の導電性の金属質母材とその上に被覆されている誘電体の構造の一例を示す斜視図である。
【図４】本発明に有用な大気圧プラズマ放電処理装置の一例を示す概略図である。
【図５】本発明に有用な大気圧プラズマ放電処理装置の一例を示す概略図である。
【図６】本発明に有用な大気圧プラズマ放電処理装置の一例を示す概略図である。
【図７】本発明に有用な大気圧プラズマ放電処理装置の一例を示す概略図である。
【図８】本発明に有用な図４に酸化性処理室を付加した大気圧プラズマ放電処理装置の一例を示す概略図である。
【符号の説明】
３２　放電空間
３５　ロール回転電極
３６　角筒型固定電極群
４１　第１電源
４２　第２電源
４３　第１フィルター
４４　第２フィルター[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides a method for forming a transparent conductive film, which forms a transparent conductive film suitable for various electronic elements such as a liquid crystal display element, an organic electroluminescence element, a plasma display panel, electronic paper, a touch panel and a solar cell on a base material, and The present invention relates to a substrate having a transparent conductive film.
[0002]
[Prior art]
Articles having a transparent conductive film having a low electric resistance (low specific resistance value) and a high visible light transmittance, such as a transparent conductive film, are conventionally used for a liquid crystal image display device, an organic EL image display device, a plasma display panel, and a field emission device. It is used in many fields such as a transparent electrode of a flat display such as a flat panel display, a transparent electrode of a solar cell, electronic paper, a touch panel, an electromagnetic wave shielding material, and an infrared reflection film. As the transparent conductive film, a metal film of Pt, Au, Ag, Cu, etc., SnO₂, In₂O₃, CdO, ZnO, Sb-doped SnO₂, F-doped SnO₂, Al-doped ZnO, Sn-doped In₂O₃Oxide film, chalcogenide, LaB with oxide or dopant such as₆, TiN, TiC and the like. Above all, a tin-doped indium oxide (hereinafter sometimes referred to as ITO) film is most widely used because of its excellent electrical properties and ease of processing by etching, but a transparent conductive film such as ITO is usually formed by magnetron sputtering. It is formed by the method.
[0003]
However, the magnetron sputtering method requires a large-scale vacuum apparatus, and is inferior in productivity and cost. Further, both the electrical characteristics such as low resistance, small change in resistance value (hereinafter sometimes referred to as robustness) when stored under high temperature and high humidity (50 to 100 ° C.), and both etching characteristics Has not been satisfied.
[0004]
On the other hand, it has been proposed that high-quality thin films can be obtained not only with ITO but also with high productivity by using the atmospheric pressure plasma discharge treatment method, but the cost is increased because helium and argon used for the discharge gas are expensive. It is causing. For this reason, it is conceivable to use an inexpensive gas other than the rare gas as the discharge gas, for example, oxygen gas, nitrogen gas, carbon dioxide, or the like in the air component. Strength), and it was found that stable discharge was difficult to obtain.
[0005]
Japanese Patent Application Laid-Open No. H10-154598 discloses that by using a pulsed electric field, a discharge can be achieved even with a gas having a high discharge starting electric field such as nitrogen gas. In addition to obtaining a high quality film, the film forming speed is low and the productivity is very low.
[0006]
Japanese Patent Application Laid-Open No. H11-16696 discloses that oxygen gas or a mixed gas of oxygen gas and rare gas is activated or ionized by applying a low-frequency voltage to a preliminary discharge electrode, and then the ionized or activated gas is discharged. Together with oxygen gas not ionized or activated, or a mixed gas of oxygen gas and a rare gas, is sent to a main discharge electrode attached to the preliminary discharge electrode under atmospheric pressure, between the main discharge electrodes. A method is described in which a high-frequency voltage is applied to generate plasma, and active species generated by the plasma are used to etch the surface of an object to be processed or ashing an organic substance on the surface of the object.
[0007]
However, according to the study of the present inventors, when the above method is applied to the formation of a thin film, oxygen gas or a mixed gas of oxygen gas and rare gas is ionized or activated by applying a low-frequency electric field between the preliminary discharge electrodes. When the high-frequency electric field is applied to the main discharge electrode by mixing the oxidized gas and the thin film-forming gas introduced just before the main discharge electrode, particles are generated, and the thin film is hardly formed. Was. Further, if oxygen gas in a plasma state and a thin film forming gas are mixed, there is a risk of explosion, and it has been found that this method is not suitable as a thin film forming method.
[0008]
In addition, a stable discharge state can be achieved by superimposing a pulsed high-frequency electric field and a pulsed DC electric field from one electrode using argon as a discharge gas, thereby forming a thin film. Is disclosed (for example, refer to Patent Document 1). However, in the film forming method disclosed above, first, plasma is generated by a DC pulse electric field as a trigger, and thereafter, switching to a high-frequency pulse electric field is performed, and after the plasma is stabilized, the substrate is introduced into the plasma. Yes, there is. That is, the DC pulse electric field and the high frequency pulse electric field are not superimposed during the film formation. According to the study of the present inventors, it has been found that a high-performance thin film cannot be formed by such an electric field application method.
[0009]
In addition, an electronic component mounting method is disclosed in which a high-frequency electric field and a low-frequency electric field are superimposed, and a process of cleaning a base material with generated plasma using nitrogen gas is disclosed (for example, see Patent Document 2). Although only cleaning of electronic components is disclosed, it has been found that it is difficult to form a high-performance thin film simply by superimposing a low frequency and a high frequency.
[0010]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2002-110397 (Claims)
[0011]
[Patent Document 2]
Japanese Patent Application Laid-Open No. 11-191576 (claims)
[0012]
[Problems to be solved by the invention]
An object of the present invention is to achieve high-density plasma, have a low resistance value, do not deteriorate the specific resistance value even when left under high-humidity and high-temperature conditions, have a high hardness, and have a high-quality transparent excellent in etching performance. An object of the present invention is to provide a method for forming a conductive film, and to provide a substrate having a high-quality and high-performance transparent conductive film manufactured by the method at low cost.
[0013]
[Means for Solving the Problems]
The present inventors have conducted intensive studies and found that, by using an electric field in which a specific high-frequency electric field is superimposed between opposed electrodes composed of two electrodes in an atmospheric pressure discharge treatment, the intensity of a discharge starting electric field such as nitrogen is large. A high-density transparent conductive film with high etching performance can be produced even with a discharge gas because high-density plasma can be generated, has a low resistance value, does not deteriorate in specific resistance even when left under high-humidity and high-temperature conditions, and has excellent etching performance. It has been found that they can be formed at low cost, can be operated safely at low cost, and can achieve a reduction in environmental load.
[0014]
That is, the object of the present invention is achieved by adopting the following configuration.
[1] At a pressure of or near atmospheric pressure, a gas containing a transparent conductive film forming gas is supplied to the discharge space,
Exciting the gas by applying a high-frequency electric field to the discharge space, in the method of forming a transparent conductive film to form a thin film on the substrate by exposing the substrate to the excited gas,
The high-frequency electric field is obtained by superimposing a first high-frequency electric field and a second high-frequency electric field;
The frequency ω of the first high-frequency electric field₁The frequency ω of the second high-frequency electric field₂Is high,
The intensity V of the first high-frequency electric field₁, The intensity V of the second high-frequency electric field₂And the relationship with the intensity IV of the discharge starting electric field,
V₁≧ IV> V₂
Or V₁> IV ≧ V₂Meet,
A method for forming a transparent conductive film, comprising:
[0015]
[2] The method for forming a transparent conductive film according to [1], wherein the discharge space is constituted by a first electrode and a second electrode facing each other.
[0016]
[3] The output density of the second high-frequency electric field is 50 W / cm²The method for forming a transparent conductive film according to [1] or [2], wherein:
[0017]
[4] The output density of the second high-frequency electric field is 20 W / cm²The method for forming a transparent conductive film according to [3], wherein:
[0018]
[5] The output density of the first high-frequency electric field is 1 W / cm²The method for forming a transparent conductive film according to any one of [1] to [4], characterized by the above.
[0019]
[6] The output density of the first high-frequency electric field is 50 W / cm²The method for forming a transparent conductive film according to [5], wherein:
[0020]
[7] The method for forming a transparent conductive film according to any one of [1] to [6], wherein at least the second high-frequency electric field is a sine wave.
[0021]
[8] A feature is that a voltage for forming the first high-frequency electric field is applied to the first electrode, and a voltage for forming the second high-frequency electric field is applied to the second electrode. 1] The method for forming a transparent conductive film according to any one of [7].
[0022]
[9] The transparent conductive film according to any one of [1] to [8], wherein 90 to 99.9% by volume of the total gas supplied to the discharge space is a discharge gas. Forming method.
[0023]
[10] The method for forming a transparent conductive film according to [9], wherein the discharge gas contains 50 to 100% by volume of nitrogen gas.
[0024]
[11] The discharge gas contains 50 to 100% by volume of a mixed gas of nitrogen and oxygen or a nitrogen gas in a volume ratio of 50:50 to 100: 0 of nitrogen gas: oxygen gas [ [10] The method for forming a transparent conductive film according to [10].
[0025]
[12] The method for forming a transparent conductive film according to [11], wherein the discharge gas contains a rare gas of less than 50% by volume.
[0026]
[13] The output density of the second high-frequency electric field is 1 W / cm²The method for forming a transparent conductive film according to any one of [1] to [12], characterized by the above.
[0027]
[14] The output density of the first high-frequency electric field is 1 W / cm²[13] The method for forming a transparent conductive film according to [13].
[0028]
[15] The method according to any one of [1] to [14], wherein the transparent conductive film forming gas contains at least one selected from an organometallic compound, a metal halide, and a metal hydride compound. Method for forming a transparent conductive film.
[0029]
[16] The organic metal compound contains at least one compound selected from an organic silicon compound, an organic titanium compound, an organic tin compound, an organic zinc compound, an organic indium compound and an organic aluminum compound [15]. 3. The method for forming a transparent conductive film according to item 1.
[0030]
[17] The method for forming a transparent conductive film according to [16], wherein the organometallic compound is represented by the following general formula (I).
[0031]
General formula (I) R¹ _xMR² _yR³ _z
Where M is a metal, R¹Is an alkyl group, R²Is an alkoxy group, R³Is a group selected from a β-diketone complex group, a β-ketocarboxylic acid ester complex group, a β-ketocarboxylic acid complex group, and a ketooxy group (ketooxy complex group), where x + y + z = m Yes, x = 0 to m, y = 0 to m, z = 0 to m.
[0032]
[18] When the organometallic compound represented by the general formula (I) has at least one R²That is, the method for forming a transparent conductive film according to [17], which has an alkoxy group.
[0033]
[19] When the organometallic compound represented by the general formula (I) has at least one R³That is, [17] or [18], which has a group selected from a β-diketone complex group, a β-ketocarboxylic acid ester complex group, a β-ketocarboxylic acid complex group, and a ketooxy group (ketooxy complex group). Method for forming a transparent conductive film.
[0034]
[20] The metal of M in the organometallic compound represented by the general formula (I) is indium (In), tin (Sn), zinc (Zn), zirconium (Zr), antimony (Sb), aluminum (Al). ), At least one selected from gallium (Ga) and germanium (Ge), the method for forming a transparent conductive film according to any one of [16] to [19].
[0035]
[21] The method for forming a transparent conductive film according to any one of [1] to [20], wherein the gas contains a reducing gas.
[0036]
[22] The method for forming a transparent conductive film according to [21], wherein the reducing gas is hydrogen.
[0037]
[23] The method for forming a transparent conductive film according to any one of [1] to [22], wherein after forming the transparent conductive film, the transparent conductive film is exposed to an oxidizing gas atmosphere.
[0038]
[24] The method for forming a transparent conductive film according to [23], wherein the formation of the transparent conductive film and the exposure to the oxidizing gas atmosphere are alternately performed.
[0039]
[25] A substrate having a transparent conductive film formed by the method for forming a transparent conductive film according to any one of [1] to [24].
[0040]
[26] {At atmospheric pressure or a pressure in the vicinity thereof, supply a gas containing a transparent conductive film forming gas and a discharge gas containing nitrogen gas to the discharge space,
Exciting the gas by applying a high-frequency electric field to the discharge space, in the method of forming a transparent conductive film to form a thin film on the substrate by exposing the substrate to the excited gas,
The high-frequency electric field is obtained by superimposing a first high-frequency electric field and a second high-frequency electric field;
The frequency ω of the first high-frequency electric field₁The frequency ω of the second high-frequency electric field₂Is high,
The intensity V of the first high-frequency electric field₁, The intensity V of the second high-frequency electric field₂And the relationship with the intensity IV of the discharge starting electric field,
V₁≧ IV> V₂
Or V₁> IV ≧ V₂Meet,
A method for forming a transparent conductive film, comprising:
[0041]
[27] The method for forming a transparent conductive film according to [26], wherein the discharge space is constituted by a first electrode and a second electrode facing each other.
[0042]
[28] The output density of the second high-frequency electric field is 50 W / cm²The method for forming a transparent conductive film according to [26] or [27], wherein:
[0043]
[29] The output density of the second high-frequency electric field is 20 W / cm²The method for forming a transparent conductive film according to [28], wherein:
[0044]
[30] The output density of the first high-frequency electric field is 1 W / cm²The method for forming a transparent conductive film according to any one of [26] to [29], which is characterized by the above.
[0045]
[31] The output density of the first high-frequency electric field is 50 W / cm²The method for forming a transparent conductive film according to any one of [26] to [30], wherein:
[0046]
[32] The method for forming a transparent conductive film according to any one of [26] to [31], wherein at least the second high-frequency electric field is a sine wave.
[0047]
[33] The method is characterized in that a voltage for forming the first high-frequency electric field is applied to the first electrode, and a voltage for forming the second high-frequency electric field is applied to the second electrode. 26] The method for forming a transparent conductive film according to any one of the items [32] to [32].
[0048]
[34] The transparent conductive film according to any one of [26] to [33], wherein 90 to 99.9% by volume of the total gas supplied to the discharge space is the discharge gas. Formation method.
[0049]
[35] The method for forming a transparent conductive film according to [34], wherein the discharge gas contains 50 to 100% by volume of nitrogen gas.
[0050]
[36] The method for forming a transparent conductive film according to [34] or [35], wherein the discharge gas contains a rare gas of less than 50% by volume.
[0051]
[37] The discharge gas contains 50 to 100% by volume of a mixed gas of nitrogen and oxygen or a nitrogen gas in a volume ratio of 50:50 to 100: 0 of nitrogen gas: oxygen gas [ 26] The method for forming a transparent conductive film according to any one of the items [36] to [36].
[0052]
[38] The output density of the second high-frequency electric field is 1 W / cm²The method for forming a transparent conductive film according to any one of [26] to [37], which is characterized by the above.
[0053]
[39] the frequency ω₁The transparent conductive film forming method according to any one of [26] to [38], wherein is less than or equal to 200 kHz.
[0054]
[40] the frequency ω₂The transparent conductive film forming method according to any one of [26] to [39], wherein is not less than 800 kHz.
[0055]
[41] The method according to any one of [26] to [40], wherein the transparent conductive film forming gas contains at least one selected from an organometallic compound, a metal halide, and a metal hydride compound. Method for forming a transparent conductive film.
[0056]
[42] The organic metal compound contains at least one compound selected from an organic silicon compound, an organic titanium compound, an organic tin compound, an organic zinc compound, an organic indium compound, and an organic aluminum compound [41]. 3. The method for forming a transparent conductive film according to item 1.
[0057]
[43] The method for forming a transparent conductive film according to [42], wherein the organometallic compound is represented by the following general formula (I).
[0058]
General formula (I) R¹ _xMR² _yR³ _z
Where M is a metal, R¹Is an alkyl group, R²Is an alkoxy group, R³Is a group selected from a β-diketone complex group, a β-ketocarboxylic acid ester complex group, a β-ketocarboxylic acid complex group, and a ketooxy group (ketooxy complex group), where x + y + z = m Yes, x = 0 to m, y = 0 to m, z = 0 to m.
[0059]
[44] The organometallic compound represented by the general formula (I) has at least one R²That is, the method for forming a transparent conductive film according to [43], wherein the transparent conductive film has an alkoxy group.
[0060]
[45] {wherein the organometallic compound represented by the general formula (I) is at least one R³That is, it has a group selected from a β-diketone complex group, a β-ketocarboxylic ester complex group, a β-ketocarboxylic acid complex group, and a ketooxy group (ketooxy complex group), [43] or [44]. Method for forming a transparent conductive film.
[0061]
[46] {M of the organometallic compound represented by the general formula (I) is indium (In), tin (Sn), zinc (Zn), zirconium (Zr), antimony (Sb), aluminum (Al) ), At least one selected from gallium (Ga) and germanium (Ge), the method for forming a transparent conductive film according to any one of [43] to [45].
[0062]
[47] The method for forming a transparent conductive film according to any one of [26] to [46], wherein the gas contains a reducing gas.
[0063]
[48] The method for forming a transparent conductive film according to [47], wherein the reducing gas is hydrogen.
[0064]
[49] The method for forming a transparent conductive film according to any one of [26] to [48], wherein after forming the transparent conductive film, the transparent conductive film is exposed to an oxidizing gas atmosphere.
[0065]
[50] The method for forming a transparent conductive film according to [49], wherein the formation of the transparent conductive film and the exposure to the oxidizing gas atmosphere are alternately performed.
[0066]
[51] A substrate comprising a transparent conductive film formed by the method for forming a transparent conductive film according to any one of [26] to [50].
[0067]
There are also the following embodiments.
(101) At an atmospheric pressure or a pressure close to the atmospheric pressure, a gas containing a discharge gas and a gas for forming a transparent conductive film is supplied between the first electrode and the second electrode facing each other, and the first electrode and the A method for forming a transparent conductive film, wherein a gas is excited by applying a high-frequency electric field between two electrodes to form a thin film on the substrate by exposing the substrate to the excited gas, The high frequency electric field has a first frequency ω₁And the first frequency ω₁Higher second frequency ω₂A method for forming a transparent conductive film, comprising a component obtained by superimposing an electric field component of:
[0068]
(102) the second frequency ω₂The method for forming a transparent conductive film according to (101), wherein the electric field waveform is a sine wave.
[0069]
(103) the first frequency ω₁Is 200 kHz or less, the method for forming a transparent conductive film according to (101) or (102).
[0070]
(104) the second frequency ω₂Is 800 kHz or more, the method for forming a transparent conductive film according to any one of (101) to (103).
[0071]
(105) The high-frequency electric field is the intensity V of the first high-frequency electric field.₁And the intensity V of the second high-frequency electric field₂The method for forming a transparent conductive film according to any one of (1) to (4), wherein
[0072]
(106) Intensity V of the first high-frequency electric field₁, The intensity V of the second high-frequency electric field₂And the relationship with the intensity IV of the discharge starting electric field,
V₁≧ IV> V₂
Or V₁> IV ≧ V₂
(105). The method for forming a transparent conductive film according to (105), wherein
[0073]
(107) The method according to any one of (101) to (106), wherein the first high-frequency electric field is applied to the first electrode, and the second high-frequency electric field is applied to the second electrode. The method for forming a transparent conductive film according to the above.
[0074]
(108) At an atmospheric pressure or a pressure close to the atmospheric pressure, a gas containing a discharge gas and a transparent conductive film forming gas as components is supplied between the first electrode and the second electrode facing each other, and the first electrode and the A method for forming a transparent conductive film, wherein a gas is excited by applying a high-frequency electric field between two electrodes to form a thin film on the substrate by exposing the substrate to the excited gas, The high-frequency electric field has a strength V of the first high-frequency electric field.₁And the intensity V of the second high-frequency electric field₂Are superimposed, and when the strength of the electric field at the start of the discharge is IV,
V₁≧ IV> V₂
Or V₁> IV ≧ V₂
A method for forming a transparent conductive film, characterized by satisfying the following.
[0075]
(109) Intensity V of the first high-frequency electric field₁The first frequency ω when applying₁The intensity V of the second high-frequency electric field₂The second frequency ω when applying₂The method of forming a transparent conductive film according to (108), wherein
[0076]
(110) the first frequency ω₁Is 200 kHz or less, the method for forming a transparent conductive film according to (109), wherein
[0077]
(111) the second frequency ω₂Is not less than 800 kHz, the method for forming a transparent conductive film according to (109) or (110).
[0078]
(112) The method for forming a transparent conductive film according to any one of (108) to (111), wherein the electric field waveform of the second high-frequency electric field is a sine wave.
[0079]
(113) Any one of (101) to (112), wherein 90 to 99.9% by volume of the total gas supplied between the first electrode and the second electrode is a discharge gas. 2. The method for forming a transparent conductive film according to claim 1.
[0080]
(114) The discharge gas contains 50 to 100% by volume of a mixed gas of nitrogen and oxygen or a nitrogen gas in a volume ratio of 50:50 to 100: 0 of nitrogen gas: oxygen gas. 101) The method for forming a transparent conductive film according to any one of the items (113) to (113).
[0081]
(115) The method for forming a transparent conductive film according to any one of (101) to (114), wherein the discharge gas contains less than 50% by volume of a rare gas.
[0082]
(116) The transparent conductive film forming gas contains at least one additional gas selected from an organometallic compound, a metal halide, and a metal hydride compound. 3. The method for forming a transparent conductive film according to item 1.
[0083]
(117) The method for forming a transparent conductive film according to (116), wherein the organometallic compound is represented by the following general formula (I).
[0084]
General formula (I) R¹ _xMR² _yR³ _z
Where M is a metal, R¹Is an alkyl group, R²Is an alkoxy group, R³Is a group selected from a β-diketone complex group, a β-ketocarboxylic ester complex group, a β-ketocarboxylic acid complex group, and a ketooxy group (ketooxy complex group). When the valence of the metal M is m, x + y + z = m Yes, x = 0 to m or x = 0 to m-1, y = 0 to m, z = 0 to m.
[0085]
(118) The organometallic compound represented by the general formula (I) has at least one R²(117) The method for forming a transparent conductive film according to (117), wherein the transparent conductive film has an alkoxy group.
[0086]
(119) {wherein the organometallic compound represented by the general formula (I) has at least one R³(17) or (18), which has a group selected from a β-diketone complex group, a β-ketocarboxylic ester complex group, a β-ketocarboxylic acid complex group, and a ketooxy group (ketooxy complex group). A method for forming a transparent conductive film.
[0087]
(20) The metal of M of the organometallic compound represented by the general formula (I) is indium (In), tin (Sn), zinc (Zn), zirconium (Zr), antimony (Sb), aluminum (Al). ), At least one selected from gallium (Ga) and germanium (Ge), the method for forming a transparent conductive film according to any one of (117) to (119).
[0088]
(121) The method for forming a transparent conductive film according to any one of (101) to (20), wherein the gas contains a reducing gas.
[0089]
(122) The method for forming a transparent conductive film according to (121), wherein the reducing gas is hydrogen.
[0090]
(123) The method for forming a transparent conductive film according to any one of (101) to (122), wherein after forming the transparent conductive film, the transparent conductive film is exposed to an oxidizing gas atmosphere.
[0091]
(124) The method for forming a transparent conductive film according to (123), wherein the formation of the transparent conductive film and the exposure to the oxidizing gas atmosphere are alternately performed.
[0092]
(125) The method for forming a transparent conductive film according to (123) or (124), wherein the oxidizing gas is at least one gas selected from oxygen, hydrogen peroxide, ozone, and air.
[0093]
(126) A substrate having a transparent conductive film formed by the method for forming a transparent conductive film according to any one of (101) to (125).
[0094]
In the present invention, the atmospheric pressure plasma discharge treatment is performed under the atmospheric pressure or a pressure near the atmospheric pressure, and the pressure at or near the atmospheric pressure is about 20 kPa to 110 kPa, and the good effects described in the present invention are obtained. Therefore, 93 kPa to 104 kPa is preferable.
[0095]
In the method for forming a transparent conductive film of the present invention, the gas supplied between the opposing electrodes (discharge space) is at least a discharge gas excited by an electric field and a plasma state or an excited state by receiving the energy to form a transparent conductive film. Containing a transparent conductive film forming gas.
[0096]
At atmospheric pressure or a pressure near that, a gas containing a transparent conductive film forming gas is supplied to the discharge space,
Exciting the gas by applying a high-frequency electric field to the discharge space, in the method of forming a transparent conductive film to form a thin film on the substrate by exposing the substrate to the excited gas,
The high-frequency electric field is obtained by superimposing a first high-frequency electric field and a second high-frequency electric field;
The frequency ω of the first high-frequency electric field₁The frequency ω of the second high-frequency electric field₂Is high,
The intensity V of the first high-frequency electric field₁, The intensity V of the second high-frequency electric field₂And the relationship with the intensity IV of the discharge starting electric field,
V₁≧ IV> V₂
Or V₁> IV ≧ V₂Meet,
In the method for forming a transparent conductive film, high frequency refers to a method having a frequency of at least 0.5 kHz.
[0097]
When the superposed high frequency electric fields are both sine waves, the frequency ω of the first high frequency electric field₁And the frequency ω₁Higher second high frequency electric field frequency ω₂Is a component obtained by superimposing and the waveform has a frequency ω₁Higher frequency ω on the sine wave of₂Sine waves are superimposed to form a sawtooth waveform.
[0098]
In the present invention, the intensity of the electric field at the start of discharge means the minimum electric field intensity capable of causing a discharge in a discharge space (such as the configuration of an electrode) and reaction conditions (such as gas conditions) used in an actual method for forming a transparent conductive film. Refers to Although the discharge starting electric field intensity varies somewhat depending on the kind of gas supplied to the discharge space, the kind of dielectric material of the electrode, the distance between the electrodes, and the like, in the same discharge space, it is dominated by the discharge start electric field intensity of the discharge gas.
[0099]
It is presumed that by applying the high-frequency electric field as described above to the discharge space, a discharge capable of forming a thin film is caused, and high-density plasma necessary for forming a high-quality transparent conductive film can be generated.
[0100]
Although superposition of a continuous wave such as a sine wave has been described above, the present invention is not limited to this, and both may be pulse waves, one may be a continuous wave, and the other may be a pulse wave. Further, a third electric field may be further provided.
[0101]
As a specific method of applying the high-frequency electric field of the present invention to the same discharge space, a frequency ω is applied to a first electrode constituting a counter electrode.₁And the electric field strength V₁Is connected to a first power supply for applying a first high-frequency electric field, and a frequency ω is applied to a second electrode.₂And the electric field strength V₂Atmospheric pressure plasma discharge processing apparatus connected to a second power supply for applying a second high frequency electric field.
[0102]
The above-mentioned atmospheric pressure plasma discharge processing apparatus includes a gas supply unit that supplies a discharge gas and a transparent conductive film forming gas between the opposed electrodes. Further, it is preferable to have an electrode temperature control means for controlling the temperature of the electrode.
[0103]
Preferably, a first filter is connected to the first electrode, the first power supply or any one of them, and a second filter is connected to the second electrode, the second power supply or any one of them. The first filter facilitates passage of a first high frequency electric field current from the first power supply to the first electrode, grounds a second high frequency electric field current, and provides a second high frequency electric field from the second power supply to the first power supply. It makes it difficult to pass a high-frequency electric field current. On the other hand, the second filter makes it easy to pass the current of the second high-frequency electric field from the second power supply to the second electrode, grounds the current of the first high-frequency electric field, and connects the second high-frequency electric field from the first power supply to the second high-frequency electric field. A device having a function of making it difficult to pass the current of the first high-frequency electric field to the power supply is used. Here, “hard to pass” means that preferably only 20% or less, more preferably 10% or less of the current is passed. Conversely, easy passage means that 80% or more, more preferably 90% or more of the current is passed.
[0104]
Further, it is preferable that the first power supply of the atmospheric pressure plasma discharge processing apparatus of the present invention has a capability of applying a high frequency electric field strength higher than that of the second power supply.
[0105]
Here, the high-frequency electric field intensity (applied electric field intensity) and the discharge starting electric field intensity referred to in the present invention are measured by the following methods.
[0106]
High frequency electric field strength V₁And V₂(Unit: kV / mm) Measurement method:
A high-frequency voltage probe (P6015A) is installed in each electrode unit, and an output signal of the high-frequency voltage probe is connected to an oscilloscope (TDS3012B, manufactured by Tektronix) to measure the electric field strength.
[0107]
Measuring method of discharge start electric field intensity IV (unit: kV / mm):
A discharge gas is supplied between the electrodes to increase the electric field intensity between the electrodes, and the electric field intensity at which the discharge starts is defined as a discharge start electric field intensity IV. The measuring device is the same as the above-mentioned high frequency electric field strength measurement.
[0108]
The positional relationship between the high-frequency voltage probe and the oscilloscope used for the above measurement is shown in FIG. 1 described later.
[0109]
By adopting the discharge conditions defined in the present invention, even with a discharge gas having a high discharge start electric field strength such as nitrogen gas, a discharge can be started, a high-density and stable plasma state can be maintained, and a high-performance transparent conductive film can be obtained. The formation can be performed.
[0110]
When the discharge gas is nitrogen gas according to the above measurement, the discharge start electric field intensity IV (1/2 V_pp) Is about 3.7 kV / mm, and therefore, in the above relationship, the first high-frequency electric field strength is V₁By applying a voltage of ≧ 3.7 kV / mm, the nitrogen gas can be excited to be in a plasma state.
[0111]
Here, the frequency of the first power supply is preferably 200 kHz or less. The electric field waveform may be a continuous wave or a pulse wave. The lower limit is desirably about 1 kHz.
[0112]
On the other hand, the frequency of the second power supply is preferably 800 kHz or more. As the frequency of the second power supply is higher, the plasma density is higher, and a dense and high-quality transparent conductive film can be obtained. The upper limit is desirably about 200 MHz.
[0113]
Applying a high-frequency electric field from such two power sources is necessary to start the discharge of a discharge gas having a high discharge starting electric field strength by the first high-frequency electric field, and to apply a high frequency of the second high-frequency electric field. It is an important point of the present invention that a dense and high-quality transparent conductive film is formed by increasing the plasma density with a high output density.
[0114]
Further, by increasing the output density of the first high-frequency electric field, the output density of the second high-frequency electric field can be improved while maintaining the uniformity of the discharge. As a result, further uniform high-density plasma can be generated, and further improvement in film forming speed and improvement in film quality can be achieved.
[0115]
In the atmospheric pressure plasma discharge processing apparatus used in the present invention, the first filter facilitates passage of a current of a first high-frequency electric field from a first power supply to a first electrode, and grounds a current of a second high-frequency electric field to ground. Thus, it is difficult to pass the current of the second high-frequency electric field from the second power supply to the first power supply. On the other hand, the second filter makes it easy to pass the current of the second high-frequency electric field from the second power supply to the second electrode, grounds the current of the first high-frequency electric field, and connects the second high-frequency electric field from the first power supply to the second high-frequency electric field. It makes it difficult for the current of the first high-frequency electric field to pass to the power supply. In the present invention, any filter having such properties can be used without limitation.
[0116]
For example, as the first filter, a capacitor of several tens pF to several tens of thousands pF or a coil of several μH can be used according to the frequency of the second power supply. As the second filter, a coil of 10 μH or more according to the frequency of the first power supply is used, and grounding via these coils or capacitors can be used as a filter.
[0117]
As described above, the atmospheric pressure plasma discharge treatment apparatus used in the present invention discharges between the opposing electrodes, brings the gas introduced between the opposing electrodes into a plasma state, and allows the gas to stand still or between the opposing electrodes. The thin film is formed on the substrate by exposing the transferred substrate to the gas in the plasma state. As another method, an atmospheric pressure plasma discharge treatment apparatus discharges gas between the opposite electrodes as described above to excite or introduce a gas introduced between the opposite electrodes into a plasma state, and excites or jets a gas outside the opposite electrode. Jet-type apparatus for forming a transparent conductive film on a substrate by blowing out a gas in a plasma state and exposing a substrate (which may be left still or transferred) near the counter electrode. There is.
[0118]
As described above, in the atmospheric pressure plasma discharge treatment method according to the present invention, a gas is introduced between opposed electrodes (discharge space), a high-frequency electric field is applied to the two electrodes to cause discharge, and the discharge gas is excited to excite the plasma. In this method, a transparent conductive film is formed on the base material by exposing the base material to a transparent conductive film forming gas that has been excited by receiving energy from a discharge gas in a plasma state to be in a plasma state. There are roughly the following four methods, such as how to introduce such a gas between the counter electrodes (discharge space) and where to form a transparent conductive film on the substrate. However, the present invention is not limited to these.
[0119]
1) A mixed gas containing a discharge gas and a transparent conductive film forming gas as components is introduced into a discharge space, a high-frequency electric field is applied to generate a discharge, and the transparent conductive film forming gas is turned into a plasma state. A method of exposing a substrate to a transparent conductive film forming gas in a plasma state
2) A mixed gas containing discharge gas and transparent conductive film forming gas as components is introduced into a discharge space, and a high-frequency electric field is applied to generate a discharge to make the transparent conductive film forming gas into a plasma state. A method in which the transparent conductive film forming gas in a state is jetted out of the discharge space (processing space) where the base material is, and the base material is exposed to the transparent conductive film forming gas in the plasma state in the processing space.
3) A discharge gas and a transparent conductive film forming gas are separately introduced into a discharge space, a high-frequency electric field is applied to generate a discharge, and the transparent conductive film forming gas is turned into a plasma state. Method of exposing substrate to forming gas
4) A discharge gas is introduced into the discharge space, and a high-frequency electric field is applied to generate a discharge to excite the discharge gas into a plasma state, which is jetted into the processing space and jetted into the processing space separately. The discharge gas in the plasma state is introduced into the space, and the discharge gas in the plasma state is converted from the discharge space into the transparent conductive film formation gas in the plasma state generated by bringing the discharge gas in the plasma state into contact with the transparent conductive film formation gas separately introduced into the processing space. A method of exposing a substrate.
[0120]
The atmospheric pressure plasma discharge treatment methods of the four methods 1) to 4) and their apparatuses will be described below with reference to the drawings.
[0121]
FIG. 1 is a schematic diagram showing an example of an atmospheric pressure plasma discharge processing apparatus useful for the present invention.
[0122]
The atmospheric pressure plasma discharge processing apparatus of the present invention is an apparatus having at least a plasma discharge processing apparatus 30, a voltage applying unit 40 having two power supplies, a gas supply unit 50, and an electrode temperature adjusting unit 60.
[0123]
FIG. 1 shows a discharge gas and a transparent conductive film forming gas from a gas supply means 50 between a counter electrode (discharge space) 32 between a roll rotating electrode (first electrode) 35 and a rectangular cylindrical fixed electrode group (second electrode) 36. Is a device for introducing a mixed gas MG mixed with and then performing a plasma discharge treatment on the substrate F to form a transparent conductive film.
[0124]
A first power supply is provided in the discharge space (between the counter electrodes) 32 between the roll rotating electrode (first electrode) 35 and the rectangular cylindrical fixed electrode group (second electrode) 36, and in the roll rotating electrode (first electrode) 35. 41 to frequency ω₁, Electric field strength V₁, Current I₁And a square-tube fixed electrode group (second electrode) 36 from the second power source 42 to the frequency ω.₂, Electric field strength V₂, Current I₂The second high frequency electric field is applied.
[0125]
A first filter 43 is provided between the roll rotating electrode (first electrode) 35 and the first power supply 41, and the first filter 43 easily passes a current from the first power supply 41 to the first electrode. The current from the second power supply 42 is designed to be grounded so that the current from the second power supply 42 to the first power supply does not easily pass. In addition, a second filter 44 is provided between the prismatic fixed electrode group (second electrode) 36 and the second power supply 42, and the second filter 44 transmits the second filter 44 from the second power supply 42 to the second electrode. , And the current from the first power supply 41 is grounded so that the current from the first power supply 41 to the second power supply is difficult to pass.
[0126]
In the present invention, the roll rotating electrode 35 may be the second electrode, and the rectangular fixed electrode group 36 may be the first electrode (the first power source and the second power source may be connected to either). In any case, a first power supply is connected to the first electrode, and a second power supply is connected to the second electrode. Further, the first power supply has a higher high-frequency electric field strength (V₁> V₂) As long as they have the ability to apply The frequency is ω₁<Ω₂What is necessary is just to have the ability to become.
[0127]
The current is I₁<I₂It is preferable that Current I of the first high-frequency electric field₁Is preferably 0.3 mA / cm²~ 20mA / cm², More preferably 1.0 mA / cm²~ 20mA / cm²It is. Also, the current I of the second high-frequency electric field₂Is preferably 10 mA / cm²~ 100mA / cm², More preferably 20 mA / cm²~ 100mA / cm²It is.
[0128]
The mixed gas MG generated by the gas supply device 51 of the gas supply means 50 is introduced into the plasma discharge processing container 31 through the air supply port 52 by controlling the flow rate. The gas G is filled in the discharge space 32 and the plasma discharge processing container 31.
[0129]
The base material F is unwound from a not-shown original roll and conveyed, or is conveyed from a previous process, and is supplied with air or the like that is entrained by the nip roll 65 via the guide roll 64 and the nip roll 65. It is shut off, and is transferred between the rectangular cylindrical fixed electrode group 36 while being wound while being in contact with the roll rotating electrode 35. An electric field applied to both the roll rotating electrode (first electrode) 35 and the rectangular cylindrical fixed electrode group (second electrode) 36 generates discharge plasma between the opposing electrodes (discharge space) 32. A transparent conductive film is formed on the upper side by a gas in a plasma state while being wound while being in contact with the roll rotating electrode 35. The base material F is taken up by a take-up device (not shown) via a nip roll 66 and a guide roll 67 or transferred to the next step. The treated exhaust gas G ′ after the discharge treatment is discharged from the exhaust port 53.
[0130]
FIG. 1 shows a measuring device used for measuring the high-frequency electric field intensity and the discharge starting electric field intensity described above. With this, the high-frequency electric field intensity and the discharge starting electric field intensity can be obtained. 25 and 26 are high frequency probes, and 27 and 28 are oscilloscopes.
[0131]
During the formation of the transparent conductive film, in order to heat or cool the roll rotating electrode (first electrode) 35 and the rectangular cylindrical fixed electrode group (second electrode) 36, a medium whose temperature has been adjusted by the electrode temperature adjusting means 60 is sent. The solution is sent to both electrodes via the pipe 61 by the liquid pump P, and the temperature is adjusted from the inside of the electrodes. During the formation of the transparent conductive film, the electrode is heated or cooled from the electrode temperature adjusting means 60 via the pipe 61. Depending on the temperature of the substrate during the plasma discharge treatment, the physical properties and composition of the obtained transparent conductive film may change, and it is desirable to appropriately control this. As a temperature control medium, an insulating material such as distilled water or oil is preferably used. At the time of the plasma discharge treatment, it is desirable that the temperature inside the electrode is adjusted to be equal so that the temperature unevenness of the base material in the width direction or the longitudinal direction is minimized.
[0132]
Here, reference numerals 68 and 69 denote partition plates for separating the plasma discharge processing container 31 from the outside world.
[0133]
FIG. 2 is a perspective view showing an example of the structure of a conductive metal base material of the roll rotating electrode shown in FIG. 1 and a dielectric material coated thereon.
[0134]
In FIG. 2, the roll electrode 35a has a conductive metallic base material 35A and a dielectric 35B coated thereon. The inside is a hollow jacket for temperature control.
[0135]
FIG. 3 is a perspective view showing an example of the structure of a conductive metallic base material of a rectangular cylindrical electrode and a dielectric material coated thereon.
[0136]
3, a rectangular cylindrical electrode 36a has a coating of a dielectric 36B similar to that of FIG. 2 on a conductive metallic base material 36A, and the structure of the electrode is a metallic pipe. , It becomes a jacket so that the temperature can be adjusted during the discharge.
[0137]
The number of the rectangular cylindrical fixed electrodes is plural along the circumference larger than the circumference of the roll electrode, and the discharge area of the electrode is a full square cylindrical type facing the roll rotating electrode 35. It is expressed as the sum of the areas of the fixed electrode surfaces.
[0138]
The prismatic electrode 36a shown in FIG. 3 may be a cylindrical electrode, but the prismatic electrode has the effect of expanding the discharge range (discharge area) as compared with the cylindrical electrode, and is therefore preferably used in the present invention. .
[0139]
2 and 3, the roll electrode 35a and the rectangular cylindrical electrode 36a are formed by spraying ceramics as dielectrics 35B and 36B on conductive metallic base materials 35A and 36A, respectively, and then sealing the inorganic compound. The sealing treatment was performed using The ceramic dielectric may have a coating of about several mm, preferably about 1 mm, in one piece. As the ceramic material used for thermal spraying, alumina, silicon nitride, or the like is preferably used. Among them, alumina is particularly preferably used because alumina is easily processed. Further, the dielectric layer may be a lining treated dielectric provided with an inorganic material by glass lining.
[0140]
Examples of the conductive metallic base materials 35A and 36A include metals such as titanium metal or titanium alloy, silver, platinum, stainless steel, aluminum and iron, and composite materials of iron and ceramics or composite materials of aluminum and ceramics. Titanium metal or a titanium alloy is particularly preferred for the reasons described below.
[0141]
When a dielectric is provided on one of the electrodes, the distance between the opposing first and second electrodes is the shortest distance between the surface of the dielectric and the surface of the conductive metal base material of the other electrode. Say that. When a dielectric is provided on both electrodes, it refers to the shortest distance between the dielectric surfaces. The distance between the electrodes is determined in consideration of the thickness of the dielectric provided on the conductive metal base material, the magnitude of the applied electric field, the purpose of utilizing the plasma, and the like. Is preferably from 0.1 to 20 mm, particularly preferably from 0.5 to 2 mm.
[0142]
The details of the conductive metallic base material and the dielectric material useful in the present invention will be described later.
[0143]
As the plasma discharge processing container 31, a processing container made of Pyrex (R) glass or the like is preferably used, but a metal container can be used as long as insulation from the electrodes can be obtained. For example, a polyimide resin or the like may be attached to the inner surface of an aluminum or stainless steel frame, and the metal frame may be sprayed with ceramics to obtain insulation. It is preferable to cover both side surfaces (up to near the base material surface) of both electrodes shown in the following drawings with the above-mentioned material.
[0144]
FIG. 4 is a schematic view showing an example of an atmospheric pressure plasma discharge processing apparatus useful for the present invention.
[0145]
4, a fixed electrode (second electrode) 136 made of one block having a slit 134 in the center and a movable gantry electrode 135 (first electrode) constitute a counter electrode, and a discharge space 132 is formed between the counter electrodes. It is in. A second power supply 142 is connected to the fixed electrode 136 having a slit, and a first power supply is connected to the movable gantry electrode 135. A first power supply is connected between the first power supply 141 and the first electrode (the movable gantry electrode 135). One filter 143 is provided, and a second filter 144 is provided between the second power supply 142 and the second electrode (fixed electrode 136). A mixed gas MG of a gas composed of a discharge gas and a transparent conductive film forming gas is sent from the gas supply device to the slit 134 via the gas introduction pipe 152, and the movable frame electrode 135 (first electrode ) Is discharged to the discharge space 132, where the discharge gas is excited, and then the transparent conductive film forming gas is excited to expose the surface of the substrate F to the transparent conductive film forming gas G ° in a plasma state. Thereby, a transparent conductive film is formed. The movable mount electrode 135 can reciprocate to form a uniform transparent conductive film or to stack different types of transparent conductive films. In this case, the substrate F is preferably a glass plate. When a transparent conductive film is formed using such electrodes as a film-shaped base material to be transferred, a number of such electrodes may be arranged and subjected to plasma discharge treatment. The plasma discharge processing may be performed by disposing them.
[0146]
FIG. 5 is a schematic view showing an example of an atmospheric pressure plasma discharge processing apparatus useful for the present invention. FIG. 5 shows an atmospheric pressure plasma discharge treatment apparatus that excites a mixed gas in a discharge space and blows it out as a jet in a plasma state to form a transparent conductive film on a substrate.
[0147]
In FIG. 5, the counter electrode includes a first electrode 235 and a second electrode 236. A first power supply 241 is connected to the first electrode 235, and a second power supply 242 is connected to the second electrode 236. A first filter 243 is provided between the first electrode 235 and the first power supply 241. A second filter 244 is provided between the two electrodes 236 and the second power supply 242.
[0148]
A mixed gas MG is introduced from a gas supply device (not shown) into a space 234 (discharge space) between the first electrode 235 and the second electrode 236 and a high-frequency electric field is applied from the first electrode 235 and the second electrode 236. To generate a discharge, and blow the mixture gas MG into a plasma state under the counter electrode (lower side of the paper) in a jet state, thereby forming the mixed gas MG from the lower surface of the counter electrode and the base material F on the movable base 237. The processing space 232 is filled with a transparent conductive film forming gas G ° in a plasma state, and a transparent conductive film is formed on the base material F in the processing space 232. In this case, the substrate F is preferably a glass plate.
[0149]
A plurality of the jet-type atmospheric pressure plasma discharge treatment apparatuses are connected and arranged in series, and the gas in the same plasma state can be discharged at the same time. Therefore, the treatment can be performed many times and the treatment can be performed at high speed. If each device jets a gas in a different plasma state, a laminated transparent conductive film having different layers can be formed.
[0150]
FIG. 6 is a schematic view showing an example of an atmospheric pressure plasma discharge processing apparatus useful for the present invention.
[0151]
FIG. 6 shows that the discharge gas G2 is introduced through the slit 322 into the discharge space 332 between the first electrode of the movable gantry electrode 335 and the second electrode of the fixed electrode 336 without mixing the discharge gas and the transparent conductive film forming gas. A predetermined high-frequency electric field is applied from the first power supply 341 connected to the movable gantry electrode 335 and the second power supply 342 connected to the fixed electrode 336 to excite the discharge gas G2, and the non-electrode block 337 The transparent conductive film forming gas G1 is introduced into the discharge space 332 through the slit 321 of FIG. 3 and receives the energy of the discharge gas in the plasma state to excite the transparent conductive film forming gas G1 into the plasma state, thereby forming the transparent conductive film in the plasma state. The substrate F is exposed to the gas G ° to form a transparent conductive film. Note that a first filter 343 is provided between the movable gantry electrode 335 and the first power supply 341, and a second filter 344 is provided between the fixed electrode 336 and the second power supply 342. The reason why the discharge gas G2 and the transparent conductive film forming gas G1 are separately introduced into the discharge space is to reduce contamination of the electrodes. 352 and 353 are gas supply pipes. In FIG. 6, the conductive metal base material, the dielectric and the jacket of the electrode are omitted.
[0152]
In FIG. 6, a transparent conductive film can also be formed on the base film by using the first electrode as a roll rotating electrode as shown in FIG.
[0153]
FIG. 7 is a schematic diagram showing an example of an atmospheric pressure plasma discharge processing apparatus useful for the present invention.
[0154]
FIG. 7 is similar to FIG. 6 except that the first electrode 435 and the second electrode 436 are fixed electrodes and are opposed electrodes formed by these two electrodes. The method is characterized in that a transparent conductive film is formed by exposing the base material to the gas in the plasma state after being released into the processing space in a jet state. The discharge gas G2 is introduced between the opposing electrodes (discharge space) 432, and the discharge gas G2 is excited by applying a high-frequency electric field. The discharge gas G2 is emitted as a plasma state into the processing space 434 in a jet state. The forming gas G1 is released to the processing space 434. The transparent conductive film forming gas G1 comes into contact with a discharge gas in a plasma state in the processing space 434 and is excited to be in a plasma state. A conductive film is formed. The substrate F may be a film to be transferred or a glass plate mounted on the moving base 433. In FIG. 7, the base material F is mounted on the movable base 433. Further, as shown in FIG. 1, a transparent conductive film may be formed while winding a film of the base material F around a roll rotating body. A first power supply 441 is connected to the first electrode, and a second power supply is connected to the second electrode. A first filter 443 is provided between the first electrode 435 and the first power supply 441, and a second filter 444 is provided between the second electrode 436 and the second power supply 442. In addition, 452 and 453 are gas supply pipes.
[0155]
FIG. 8 is a schematic diagram showing an example of an atmospheric pressure plasma discharge treatment apparatus in which an oxidizing treatment chamber is added to FIG. 4 useful for the present invention.
[0156]
FIG. 8 shows a state in which a transparent conductive film is formed on a glass plate base material F mounted on a movable gantry electrode 535 similar to the movable gantry electrode 135 in the plasma discharge processing apparatus of FIG. Is moved to the oxidizing gas processing chamber 560 to perform the oxidizing gas treatment on the transparent conductive film, and the transparent conductive film is oxidized while moving the mount electrode 535 alternately with the formation of the transparent conductive film and the oxidizing gas treatment. 1 shows an atmospheric pressure plasma discharge processing apparatus capable of performing the following. The movable frame electrode (first electrode) 535 and the fixed electrode (second electrode) 536 constitute a counter electrode. As the counter electrode, a first power source 541 is connected to the movable gantry electrode (first electrode) 535, and a second power source 542 is connected to the fixed electrode (second electrode) 536, so that the first electrode 535 and the first power source are connected. A first filter 543 is provided between the second power supply 541 and the second electrode 536, and a second filter 544 is provided between the second electrode 536 and the second power supply. The mixed gas MG is introduced from a gas supply device (not shown) into the slit 521 in the fixed electrode (second electrode) 536, and the gap between the movable base electrode (first electrode) 535 and the fixed electrode (second electrode) is introduced. In the discharge space 532, a high-frequency electric field is applied to generate a discharge, the mixed gas MG is turned into a plasma state, and the base material F on the movable gantry electrode 535 is exposed to a transparent conductive film forming gas G ° in a plasma state. A transparent conductive film is formed. In this case, the substrate F is preferably a glass plate. After forming the transparent conductive film on the base material, in order to perform oxidizing gas treatment, the gate 519 is opened, the movable gantry electrode 535 is moved to the oxidizing gas treatment chamber 560, the gate is closed, and the oxidizing gas OG is removed. The transparent conductive film is exposed to an oxidizing treatment. In FIG. 8, reference numeral 552 denotes a mixed gas MG supply pipe, and 535 'denotes a movable gantry.
[0157]
Next, the high-frequency power supply, electrodes, and conditions used in the present invention will be described.
The first power supply (high-frequency power supply) installed in the atmospheric pressure plasma discharge treatment apparatus of the present invention includes:

And the like, and any of them can be used. In addition, * mark is a HEIDEN laboratory impulse high frequency power supply (100 kHz in continuous mode).
[0158]
Further, as the second power supply (high-frequency power supply),

And the like, and any of them can be preferably used.
[0159]
In the present invention, it is necessary to employ an electrode capable of generating such an electric field and maintaining a uniform glow discharge state in a plasma discharge processing apparatus.
[0160]
In the present invention, the power applied between the opposing electrodes is 1 W / cm to the second electrode (second high-frequency electric field).²It is preferable to supply the above power (output density), excite the discharge gas to generate plasma, and apply energy to the transparent conductive film forming gas to form the transparent conductive film. The upper limit of the supplied power is preferably 50 W / cm²Or less, more preferably 20 W / cm²It is as follows. The lower limit is preferably 1.2 W / cm²That is all. The discharge area (cm²) Refers to the area of the range in which discharge occurs in the electrode.
[0161]
In addition, the first electrode (first high-frequency electric field) also has 1 W / cm²By supplying the above power (output density), the output density can be improved while maintaining the uniformity of the second high-frequency electric field. As a result, more uniform high-density plasma can be generated, and further improvement in film forming speed and improvement in film quality can be achieved. Preferably 5 W / cm²That is all. The upper limit of the power supplied to the first electrode is preferably 50 W / cm²It is.
[0162]
Regarding the voltage application method, either of a continuous sine wave continuous oscillation mode called a continuous mode and an intermittent oscillation mode of intermittent ON / OFF called a pulse mode may be adopted. On the electrode side, a continuous sine wave is preferable because a denser and higher quality film can be obtained.
[0163]
An electrode used in such a method for forming a transparent conductive film by atmospheric pressure plasma must be able to withstand severe conditions in terms of structure and performance. Such an electrode is preferably a metal base material coated with a dielectric.
[0164]
In the dielectric-coated electrode used in the present invention, it is preferable that the characteristics match between various metallic base materials and the dielectric. One of the characteristics is the linear thermal expansion between the metallic base material and the dielectric. The coefficient difference is 10 × 10^-6/ ° C or lower. Preferably 8 × 10^-6/ ° C or lower, more preferably 5 × 10^-6/ ° C or lower, more preferably 2 × 10^-6/ ° C or lower. The linear thermal expansion coefficient is a physical property value of a known material.
[0165]
The difference between the coefficients of linear thermal expansion is as follows:
(1) The metallic base material is pure titanium or a titanium alloy, and the dielectric is a ceramic sprayed coating.
(2) The metallic base material is pure titanium or a titanium alloy, and the dielectric is glass lining
(3) The metallic base material is stainless steel, and the dielectric is ceramic sprayed coating
4) Metallic base material is stainless steel, dielectric is glass lining
(5) The metallic base material is a composite material of ceramics and iron, and the dielectric is a ceramic sprayed coating.
(6) The metal base material is a composite material of ceramics and iron, and the dielectric is glass lining
(7) The metallic base material is a composite material of ceramics and aluminum, and the dielectric is a ceramic sprayed coating.
(8) The metal base material is a composite material of ceramics and aluminum, and the dielectric is glass lining
Etc. From the viewpoint of the difference in linear thermal expansion coefficient, the above (1) or (2) and (5) to (8) are preferable, and (1) is particularly preferable.
[0166]
In the present invention, titanium or a titanium alloy is particularly useful as the metallic base material from the above characteristics. By using titanium or titanium alloy as the metallic base material, and by setting the dielectric material to the above, there is no deterioration of the electrode during use, especially cracking, peeling, falling off, etc., and it is used for a long time under severe conditions Can withstand.
[0167]
The metallic base material of the electrode useful in the present invention is a titanium alloy or titanium metal containing 70% by mass or more of titanium. In the present invention, the content of titanium in the titanium alloy or titanium metal can be used without any problem as long as it is 70% by mass or more, but preferably contains 80% by mass or more of titanium. As the titanium alloy or titanium metal useful for the present invention, those generally used as industrial pure titanium, corrosion-resistant titanium, high-strength titanium and the like can be used. Examples of industrial pure titanium include TIA, TIB, TIC, TID, etc., all of which contain very little iron, carbon, nitrogen, oxygen, hydrogen, etc. The content is 99% by mass or more. As the corrosion-resistant titanium alloy, T15PB can be preferably used, which contains lead in addition to the above contained atoms, and has a titanium content of 98% by mass or more. In addition, as the titanium alloy, in addition to the above atoms except for lead, T64, T325, T525, TA3, and the like containing aluminum and containing vanadium and tin can be preferably used. The amount is 85% by mass or more. These titanium alloys or titanium metals have a coefficient of thermal expansion smaller than that of stainless steel, for example, AISI 316, by about 1/2, and are combined with a later-described dielectric applied on the titanium alloy or titanium metal as a metallic base material. It can withstand high temperature and long time use.
[0168]
On the other hand, as the properties required of the dielectric, specifically, an inorganic compound having a relative dielectric constant of preferably 6 to 45 is preferable, and such dielectrics include ceramics such as alumina and silicon nitride; Alternatively, there are glass lining materials such as silicate glass and borate glass. Among these, those obtained by spraying ceramics described later and those provided by glass lining are preferable. In particular, a dielectric provided by spraying alumina is preferable.
[0169]
Alternatively, as one of the specifications that can withstand the large power as described above, the porosity of the dielectric is 10% by volume or less, preferably 8% by volume or less, preferably more than 0% by volume and 5% by volume or less. It is. The porosity of the dielectric can be measured by a BET adsorption method or a mercury porosimeter. In the examples described later, the porosity is measured using a piece of a dielectric material coated on a metallic base material using a mercury porosimeter manufactured by Shimadzu Corporation. High durability is achieved by the dielectric having a low porosity. Examples of the dielectric having such voids and low porosity include a ceramic sprayed coating having a high density and a high adhesion by an atmospheric pressure plasma spraying method described later. In order to further reduce the porosity, it is preferable to perform a sealing treatment.
[0170]
The above atmospheric pressure plasma spraying method is a technique in which fine powders such as ceramics, wires and the like are charged into a plasma heat source and sprayed as fine particles in a molten or semi-molten state onto a metal base material to be coated to form a film. . The plasma heat source is a high-temperature plasma gas in which a molecular gas is heated to a high temperature, dissociated into atoms, and further applied with energy to emit electrons. This plasma gas is sprayed at a high speed, and the sprayed material collides with the metal base material at a higher speed than conventional arc spraying or flame spraying, so that a high adhesion strength and a high-density coating can be obtained. For details, reference can be made to a thermal spraying method for forming a heat shielding film on a high-temperature exposed member described in JP-A-2000-301655. According to this method, the porosity of the dielectric material (ceramic sprayed film) to be coated as described above can be obtained.
[0171]
Another preferable specification that can withstand high power is that the thickness of the dielectric is several millimeters, more preferably 0.5 to 2 mm. This variation in film thickness is desirably 5% or less, preferably 3% or less, and more preferably 1% or less.
[0172]
In order to further reduce the porosity of the dielectric, it is preferable that the sprayed film of ceramic or the like is further subjected to sealing treatment with an inorganic compound as described above. As the inorganic compound, metal oxides are preferable, and among them, silicon oxide (SiO 2) is particularly preferable._x) Is preferable.
[0173]
It is preferable that the inorganic compound for the pore-sealing treatment is formed by curing by a sol-gel reaction. In the case where the inorganic compound for the sealing treatment contains a metal oxide as a main component, a metal alkoxide or the like is applied as a sealing liquid on the ceramic sprayed film and cured by a sol-gel reaction. When the inorganic compound is mainly composed of silica, it is preferable to use alkoxysilane as the sealing liquid.
[0174]
Here, it is preferable to use energy treatment to promote the sol-gel reaction. Examples of the energy treatment include thermal curing (preferably 200 ° C. or lower) and ultraviolet irradiation. Further, as a sealing treatment method, when the sealing liquid is diluted and coating and curing are repeated several times sequentially, the mineralization is further improved, and a dense electrode without deterioration can be obtained.
[0175]
In the case where a sealing treatment is performed by coating a ceramic sprayed film with a metal alkoxide or the like of the dielectric coated electrode according to the present invention as a sealing liquid and then performing a sealing treatment by a sol-gel reaction, the content of the cured metal oxide is 60%. It is preferably at least mol%. When alkoxysilane is used as the metal alkoxide of the sealing liquid, the cured SiO 2_x(X is 2 or less) The content is preferably 60 mol% or more. SiO after curing_xThe content is measured by analyzing a fault of the dielectric layer by XPS.
[0176]
In the electrode according to the transparent conductive film forming method of the present invention, the electrode is adjusted so that the maximum height (Rmax) of the surface roughness specified by JIS B0601 at least on the side in contact with the base material is 10 μm or less. Is preferable from the viewpoint of obtaining the effects described in the present invention, but more preferably, the maximum value of the surface roughness is 8 μm or less, and particularly preferably, it is adjusted to 7 μm or less. In this way, the thickness of the dielectric and the gap between the electrodes can be kept constant by the method of polishing and finishing the dielectric surface of the dielectric coated electrode, and the discharge state can be stabilized. Distortion and cracks due to residual stress can be eliminated, and high accuracy and durability can be greatly improved. The polishing finish of the dielectric surface is preferably performed at least on the dielectric in contact with the base material. Further, the center line average surface roughness (Ra) defined by JIS {B} 0601 is preferably 0.5 μm or less, more preferably 0.1 μm or less.
[0177]
Another preferable specification of the dielectric-coated electrode used in the present invention that withstands large power is that the heat-resistant temperature is 100 ° C. or higher. It is more preferably at least 120 ° C, particularly preferably at least 150 ° C. The upper limit is 500 ° C. Note that the heat-resistant temperature refers to the highest temperature that can withstand a state in which dielectric breakdown does not occur and discharge can be performed normally. Such a heat-resistant temperature is within the range of the above-described ceramic thermal spraying, a dielectric provided with a layered glass lining having a different amount of bubbles mixed therein, or a difference in a linear thermal expansion coefficient between the metal base material and the dielectric described below. It can be achieved by appropriately combining means for appropriately selecting the above materials.
[0178]
Next, the gas for forming the transparent conductive film of the present invention will be described. The gas used is basically a gas containing a discharge gas and a transparent conductive film forming gas as constituent components. The discharge gas and the transparent conductive film forming gas may be mixed and supplied to the discharge space or the processing space, or may be separately supplied as another embodiment as described above. When separately supplied, the ratio G2: G1 in the processing space of the discharge gas G2 and the transparent conductive film forming gas G1 is preferably 100: 1 to 5: 1. At this time, an inert gas (a gas similar to the discharge gas) is mixed in the transparent conductive film forming gas G1 at a ratio of about 99.1% by volume and a transparent conductive film forming gas is mixed at a ratio of about 0.9% by volume. Is preferred.
[0179]
The discharge gas is a gas capable of generating a glow discharge capable of forming a transparent conductive film. Examples of the discharge gas include nitrogen, a rare gas, air, hydrogen gas, and oxygen, and these may be used alone as a discharge gas or may be used as a mixture. In the present invention, the discharge gas is preferably nitrogen or a mixed gas of nitrogen and oxygen. Preferably, 50 to 100% by volume of the discharge gas is nitrogen or a mixed gas of nitrogen and oxygen. At this time, the volume ratio of nitrogen to oxygen is preferably 50 to 100 for nitrogen and 0 to 50 for oxygen. As a discharge gas other than nitrogen or a mixed gas of nitrogen and oxygen, it is preferable to contain a rare gas in an amount of less than 50% by volume. Examples of the rare gas include elements belonging to Group 18 of the periodic table, specifically, helium, neon, argon, krypton, xenon, and radon. The amount of the discharge gas is preferably 90 to 99.9% by volume based on the total amount of gas supplied to the discharge space or the processing space.
[0180]
The transparent conductive film forming gas is a raw material that receives energy from a discharge gas, excites itself and becomes active, and is chemically deposited on a substrate to form a transparent conductive film.
[0181]
Next, the transparent conductive film forming gas used in the present invention will be described.
Examples of the gas for forming a transparent conductive film used in the present invention include an organic metal compound, a halogen metal compound, and a metal hydride compound.
[0182]
In the present invention, the transparent conductive film forming gas preferably contains an organometallic compound, and a doping organometallic compound for doping a metal oxide formed from the organometallic compound may be added. Organometallic compounds are used.
[0183]
The organometallic compounds useful in the present invention are preferably those represented by the following general formula (I).
General formula (I) R¹ _xMR² _yR³ _z
Where M is a metal, R¹Is an alkyl group, R²Is an alkoxy group, R³Is a group selected from a β-diketone complex group, a β-ketocarboxylic ester complex group, a β-ketocarboxylic acid complex group, and a ketooxy group (ketooxy complex group). And x = 0 to m, y = 0 to m, and z = 0 to m, each of which is 0 or a positive integer. R¹Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group. R²Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a 3,3,3-trifluoropropoxy group. Further, a hydrogen atom of an alkyl group may be substituted with a fluorine atom. R³The group selected from the group consisting of β-diketone complex group, β-ketocarboxylic ester complex group, β-ketocarboxylic acid complex group and ketooxy group (ketooxy complex group) includes, for example, 2,4-pentane as a β-diketone complex group. Dione (also called acetylacetone or acetoacetone), 1,1,1,5,5,5-hexamethyl-2,4-pentanedione, 2,2,6,6-tetramethyl-3,5-heptanedione, , 1,1-trifluoro-2,4-pentanedione, and the like. Examples of the β-ketocarboxylic acid ester complex group include, for example, methyl acetoacetate, ethyl acetoacetate, propyl acetoacetate, and trimethylacetoacetate. Ethyl, methyl trifluoroacetoacetate and the like can be mentioned, and as β-ketocarboxylic acid, for example, , Acetoacetic acid, can be mentioned trimethyl acetoacetate, and as Ketookishi, for example, acetoxy group (or an acetoxy group), a propionyloxy group, Buchirirokishi group, acryloyloxy group, methacryloyloxy group and the like. The number of carbon atoms of these groups is preferably 18 or less, including the organometallic compounds described above. As shown in the examples, it may be a straight-chain or branched one, or a hydrogen atom substituted with a fluorine atom.
[0184]
From the viewpoint of handling in the present invention, an organometallic compound having a low risk of explosion is preferred, and an organometallic compound having at least one or more oxygen atoms in the molecule is preferred. As such R²Ie, an organometallic compound containing at least one alkoxy group;³That is, a metal compound having at least one group selected from a β-diketone complex group, a β-ketocarboxylic ester complex group, a β-ketocarboxylic acid complex group, and a ketooxy group (ketooxy complex group) is preferable.
[0185]
The metal of the organometallic compound that can be used in the present invention is not particularly limited, but indium (In), tin (Sn), zinc (Zn), zirconium (Zr), aluminum (Al) and antimony (Sb), gallium ( At least one metal selected from Ga) and germanium (Ge) is preferable, and at least one metal selected from indium, zinc and tin is particularly preferable.
[0186]
In the present invention, examples of the preferred organometallic compound include indium tris 2,4-pentanedionate (or indium trisacetoacetonate), indium tris hexafluoropentanedionate, methyltrimethylacetoxyindium, and triacetoacetoacetate. Oxyindium, triacetooxyindium, diethoxyacetoacetooxyindium, indium triisopolopoxide, diethoxyindium (1,1,1-trifluoropentanedionate), tris (2,2,6,6-tetra Methyl-3,5-heptanedionate) indium, ethoxyindium bisacetomethyl acetate, di (n) butylbis (2,4-pentanedionate) tin, di (n) butyldiacetoxytin, di (t) Butyldia Tookishi tin, tetraisopropoxy tin, tetra (i) butoxy tin, can be mentioned zinc 2,4-pentanedionate, etc., both also preferably used.
[0187]
Among these, indium tris 2,4-pentanedionate, tris (2,2,6,6-tetramethyl-3,5-heptanedionate) indium, zinc bis 2,4-pentanedionate, di ( n) Butyl diacetoxytin is preferred. These organometallic compounds are generally commercially available (for example, from Tokyo Chemical Industry Co., Ltd.).
[0188]
In the present invention, the mixed gas preferably contains an organic metal compound for doping or a fluorine compound for doping for further increasing the conductivity of the transparent conductive film formed from the organic metal compound. Examples of the doping organometallic compound or the doping fluorine compound include triisopropoxyaluminum, nickel tris 2,4-pentanedionate, manganese bis 2,4-pentanedionate, boron isopropoxide, and tri (n) butoxy. Antimony, tri (n) butylantimony, di (n) butyltin bis 2,4-pentanedionate, di (n) butyldiacetoxytin, di (t) butyldiacetoxytin, tetraisopropoxytin, tetra Butoxytin, tetrabutyltin, zinc 2,4-pentanedionate, dipropoxygermanium, di (n) butyldiacetoxygermanium, germanium tris 2,4-pentanedionate, gallium tris 2,4-pentanedionate, tri Propoxygallium, butyldiacetate Kishigariumu, hexafluoropropylene, eight fluoride cyclobutane can be exemplified tetrafluoromethane like.
[0189]
The ratio between the organometallic compound necessary for forming the transparent conductive film and the doping ratio varies depending on the type of the transparent conductive film to be formed. For example, in an ITO film obtained by doping tin with indium oxide, In : It is necessary to adjust the amount of the transparent conductive film forming gas so that the atomic ratio of Sn is in the range of 100: 0.1 to 100: 15. Preferably, the adjustment is made to be 100: 0.5 to 100: 10. In a transparent conductive film obtained by doping tin oxide with fluorine (a fluorine-doped tin oxide film is referred to as an FTO film), the atomic ratio of Sn: F in the obtained FTO film is 100: 0.01 to 100: 50. It is preferable to adjust the amount ratio of the transparent conductive film forming gas so as to fall within the range described above. In₂O₃-In the ZnO transparent conductive film, it is preferable to adjust the amount ratio of the transparent conductive film forming gas so that the atomic ratio of In: Zn is in the range of 100: 50 to 100: 5. The respective atomic ratios of In: Sn, Sn: F and In: Zn can be determined by XPS measurement.
[0190]
In the present invention, the obtained transparent conductive film is, for example, SnO₂, In₂O₃, ZnO oxide film, or Sb-doped SnO₂, FTO, Al-doped ZnO, Zn-doped In (sometimes referred to as IZO), Zr-doped In, and complex oxides doped with dopants such as ITO, and at least one selected from these as a main component. Amorphous films are preferred. In addition, chalcogenide, LaB₆, A non-oxide film such as TiN and TiC, a metal film such as Pt, Au, Ag, and Cu, and a transparent conductive film such as CdO.
[0191]
The transparent conductive film forming gas of the organometallic compound is preferably contained in the total gas in an amount of 0.01 to 10% by volume, more preferably 0.1 to 3% by volume.
[0192]
The gas used in the present invention preferably contains a reducing gas. The reducing gas referred to in the present invention refers to a chemically reducing inorganic gas containing no oxygen in the molecule. Examples of the reducing gas include hydrogen, hydrogen sulfide, hydrocarbons such as methane, and water, but hydrogen gas is preferable. The amount of the reducing gas is 0.0001 to 5.0% by volume, preferably 0.001 to 3.0% by volume, based on the total gas. By including the reducing gas, the reducing gas acts on the gas forming the transparent conductive film, and the formed transparent conductive film can be more uniformly and densely formed, and the conductivity and the etching performance can be improved. Can be done.
[0193]
A gas that does not directly participate in the formation of the transparent conductive film but affects the properties of the transparent conductive film is called an auxiliary gas or an additional gas. Auxiliary gas, in addition to reducing gas, oxygen, ozone, hydrogen peroxide, carbon dioxide, carbon monoxide, oxidizing gas such as oxygen, methane, ethane, propane, ethylene, propylene and other hydrocarbon gas, In addition, there are gases that promote the formation of the transparent conductive film. The auxiliary gas is preferably 0.0001 to 5% by volume, more preferably 0.001 to 3% by volume, based on 100% by volume of the total gas.
[0194]
The thickness of the formed metal oxide or metal composite compound transparent conductive film is preferably in the range of 0.1 to 1000 nm.
[0195]
The transparent conductive film obtained by the method for producing an article having the transparent conductive film of the present invention has a feature of high carrier mobility. As is well known, the electrical conductivity of the transparent conductive film is represented by the following equation (1).
[0196]
σ = n × e × μ (1)
Here, σ is the electric conductivity, n is the carrier density, e is the electric quantity of electrons, and μ is the mobility of the carriers. To increase the electric conductivity σ, it is necessary to increase the carrier density n or the carrier mobility μ, but as the carrier density n increases, 2 × 10²¹cm^-3Transparency is lost because the reflectance increases from the vicinity. Therefore, in order to increase the electric conductivity σ, it is necessary to increase the carrier mobility μ. According to the method for forming a transparent conductive film of the present invention, it is possible to form a transparent conductive film having a carrier mobility μ close to that of a transparent conductive film formed by DC magnetron sputtering by optimizing the conditions. It has been found.
[0197]
Since the method for forming a transparent conductive film of the present invention has a high carrier mobility μ, the specific resistance value is 1 × 10 even without doping.^-3A transparent conductive film having a specific resistance of Ω · cm or less can be obtained. By increasing the carrier density n by doping, the specific resistance can be further reduced. Further, by using a transparent conductive film forming gas for increasing the specific resistance as required, a specific resistance of 1 × 10^-2A transparent conductive film having a high specific resistance of Ω · cm or more can be obtained. Examples of the transparent conductive film forming gas used for adjusting the specific resistance of the transparent conductive film include titanium triisopropoxide, tetramethoxysilane, tetraethoxysilane, hexamethyldisiloxane, and the like.
[0198]
The transparent conductive film obtained by the method for forming a transparent conductive film of the present invention has a carrier density n of 1 × 10¹⁹cm^-3As described above, under more preferable conditions, 1 × 10²⁰cm^-3As described above, the transparency does not decrease.
[0199]
One of the excellent effects of the present invention is etching. When various display elements are used as electrodes, a patterning step of drawing a circuit on a substrate is indispensable, and whether patterning can be performed easily is an important issue in terms of process suitability. In general, patterning is often performed by photolithography, and portions that do not require conduction are dissolved and removed by etching, so that the speed of dissolution of the portions by an etchant and the absence of residues are important issues. ing. As the etchant, nitric acid, hydrochloric acid, a mixed acid of hydrochloric acid and nitric acid, hydrofluoric acid, an aqueous solution of ferric chloride, and the like are usually used, and the wet etching method is mainly used.
[0200]
As the transparent conductive film, the thickness of the formed oxide or composite oxide transparent conductive film is preferably in the range of 0.1 to 1000 nm.
[0201]
The substrate of the transparent conductive film of the present invention will be described.
The substrate on which the transparent conductive film of the present invention is formed is not particularly limited as long as a transparent conductive film can be formed on the surface thereof. There is no limitation on the form or material of the substrate as long as the substrate is exposed to the mixed gas in a plasma state and a uniform transparent conductive film is formed. Resin films, resin sheets (plates), and glass plates are suitable for the present invention.
[0202]
Since the resin film can form a transparent conductive film by continuously transferring between or near the electrodes of the atmospheric pressure plasma discharge treatment apparatus according to the present invention, it is not a batch type such as a vacuum system such as sputtering. It is suitable for mass production, and is suitable as a continuous production method with high productivity.
[0203]
Examples of the material of the resin film, the resin sheet, the resin lens, the molded article such as a resin molded article include cellulose triacetate, cellulose diacetate, cellulose esters such as cellulose acetate propionate or cellulose acetate butyrate, polyethylene terephthalate and polyethylene naphthalate. Such as polyester, polyolefin such as polyethylene and polypropylene, polyvinylidene chloride, polyvinyl chloride, polyvinyl alcohol, ethylene vinyl alcohol copolymer, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide, polyether Sulfone, polysulfone, polyetherimide, polyamide, fluororesin, polymethyl acrylate , It can be mentioned acrylate copolymer and the like.
[0204]
These materials can be used alone or in a suitable mixture. Among them, ZEONEX and ZEONOR (manufactured by ZEON CORPORATION), ARTON (manufactured by Nippon Synthetic Rubber Co., Ltd.) of amorphous cyclopolyolefin resin film, PURE ACE (manufactured by Teijin Limited) of polycarbonate film, and Konica of cellulose triacetate film Commercial products such as Tuck KC4UX and KC8UX (manufactured by Konica Corporation) can be preferably used. Furthermore, even for materials having a large intrinsic birefringence such as polycarbonate, polyarylate, polysulfone, and polyethersulfone, conditions such as solution casting film formation and melt extrusion film formation, as well as stretching conditions in the vertical and horizontal directions. What can be used can be obtained by appropriately setting the above.
[0205]
Of these, a cellulose ester film that is optically nearly isotropic is preferably used for the transparent conductive film of the present invention. As the cellulose ester film, one of those preferably used is a cellulose triacetate film or a cellulose acetate propionate as described above. As the cellulose triacetate film, commercially available Konikatak KC4UX, KC8UX and the like are useful.
[0206]
Those having a surface coated with gelatin, polyvinyl alcohol, acrylic resin, polyester resin, cellulose ester resin or the like can be used. Further, an antiglare layer, a clear hard coat layer, an antifouling layer and the like may be provided on the transparent conductive film side of these resin films. Further, an adhesive layer, an alkali barrier coat layer, a gas barrier layer, a solvent-resistant layer, and the like may be provided as necessary.
[0207]
A glass plate or a resin sheet (plate) can be used as a base material for each leaf. The resin sheet (plate) is the same as the resin described above, and examples of the glass plate include soda lime glass, borosilicate glass, ultra-high purity glass, and crystal glass. Further, the substrate according to the present invention is not limited to the above description. The thickness of the film is preferably from 10 to 1000 μm, more preferably from 40 to 200 μm. The thickness of the glass plate is preferably 0.1 to 2 mm.
[0208]
【Example】
Next, the present invention will be further described with reference to the following examples, but, needless to say, embodiments of the present invention are not limited thereto.
[0209]
〔Evaluation item〕
First, evaluation items used in the present embodiment, their contents, and criteria for determination will be described.
[0210]
《Resistivity》
It was determined by a four-terminal method according to JIS-R-1637. Note that Loresta-GP and MCP-T600 manufactured by Mitsubishi Chemical Corporation were used for the measurement.
[0211]
《Moisture resistance, heat resistance (robustness)》
The sample left at 23 ° C. and 55% RH was left at 240 ° C. and 90% RH for 240 hours using a thermostat, and then left again at 23 ° C. and 55% RH, and humidified and subjected to specific resistance before and after heating. Value (Ωcm)₀And R, the rate of change R / R₀Was used as an index of robustness. The specific resistance value used was measured in the same manner as the above specific resistance value.
[0212]
"etching"
The transparent conductive film on the substrate was immersed in an etching solution at 30 ° C. having the following composition for patterning the transparent conductive film, and the etching time was sampled at 30, 45, 60, 120, and 180 seconds. Subsequently, the sample was washed with water and dried, the cross section of the boundary between the etched portion and the non-etched portion of the dried sample was observed with an electron microscope, and the degree of film removal was visually evaluated.
[0213]
<Etching liquid composition>
A mixture of water, concentrated hydrochloric acid and a 40% by mass ferric chloride solution in a mass ratio of 85: 8: 7 was used as an etching solution.
[0214]
<Evaluation level of etching pattern>
A: The transparent conductive film can be removed in 30 seconds, and the boundary of the etching pattern is very good.
B: The transparent conductive film can be removed in 45 seconds, and the boundary of the etching pattern is very good.
C: The transparent conductive film can be removed in 60 seconds, and the boundary of the etching pattern is very good.
D: The transparent conductive film was removed in 120 seconds, but the boundary of the etching pattern was not so good.
E: Some portion of the transparent conductive film remained even after more than 180 seconds, and the boundary portion of the etching pattern was jagged (uneven).
F: Transparent conductive film remains in an island shape even after more than 180 seconds
《Pencil hardness test》
The hardness of the surface of the article having the transparent conductive film was measured and evaluated according to the pencil hardness measurement described in JIS K5200.
[0215]
Example 1
An ITO film was formed on a base film using an atmospheric pressure plasma discharge treatment apparatus having a structure similar to that shown in FIG.
[0216]
(Preparation of electrode)
In the plasma discharge processing apparatus of FIG. 1 described above, a set of a roll electrode covered with a dielectric and a plurality of rectangular cylindrical electrodes similarly covered with a dielectric was produced as follows.
[0219]
The roll electrode serving as the first electrode is made of a titanium alloy T64 jacket roll metal base material (see FIG. 2) having a roll diameter (described below), a roll cylinder length of 500 mm, and a wall thickness of 10 mm and having cooling means using cylindrical cooling water. Then, a high-density, high-adhesion alumina sprayed film was coated by an atmospheric pressure plasma method so as to have a roll diameter of 1000 mm. Thereafter, a solution obtained by diluting tetramethoxysilane with ethyl acetate was applied and dried, and then cured by irradiation with ultraviolet rays to perform a sealing treatment. The surface of the dielectric material thus coated was polished and smoothed, and processed so that Rmax was 5 μm. The final porosity of the dielectric was 5% by volume. At this time, the dielectric layer SiO_XThe content was 75 mol%. The final thickness of the dielectric was 1 mm, and the relative dielectric constant of the dielectric was 10. Further, the difference in linear thermal expansion coefficient between the conductive metal base material and the dielectric material is 1.6 × 10^-6/ ° C, and the heat-resistant temperature was 250 ° C.
[0218]
On the other hand, the square cylindrical electrode of the second electrode is similar to the above with respect to a square base titanium alloy T64 metal (hollow as shown in FIG. 3) having a side of slightly less than 40 mm, a length of 500 mm, and a wall thickness of 7 mm. Was coated under the same conditions so that one side was 40 mm, and 30 of them were prepared. The dielectric of these rectangular cylindrical electrodes is the same as that of the above-mentioned roll electrode, Rmax of the dielectric surface, and SiO of the dielectric layer._xThe content, the thickness and relative dielectric constant of the dielectric, the difference between the linear thermal expansion coefficients of the metallic base material and the dielectric, and the heat-resistant temperature of the electrode were almost the same as those of the first electrode.
[0219]
Twenty-five such prismatic electrodes were arranged around the roll rotating electrode with a gap of 1 mm between the counter electrodes. The total discharge area of the rectangular cylindrical fixed electrode group is 50 cm (length in the width direction) × 4 cm (length in the transport direction) × 30 (number of electrodes) = 6000 cm²Met.
[0220]
[Atmospheric pressure plasma discharge treatment equipment]
The atmospheric pressure plasma discharge processing apparatus shown in FIG. 1 in which a counter electrode is constituted by the square cylindrical fixed electrode group 36 and the roll rotating electrode 35 was used. With the gap between the opposing electrodes being 1 mm, the rectangular cylindrical fixed electrodes 36 were arranged at equal intervals on a circle concentric with the circle of the roll rotating electrode 35. The roll rotating electrode 35 was used as a first electrode, connected to a first power supply 41, and a first filter 43 was disposed therebetween, and each was grounded to ground. The rectangular cylindrical fixed electrode group 36 was used as a second electrode, and each rectangular cylindrical electrode was connected to a second power source, and a second filter 44 was provided between them to ground each to ground. As the first power source and the second power source, those suitable for the relationship between the high-frequency electric field and the discharge starting electric field were installed.
[0221]
(Production of a film having a transparent conductive film)
As the first power supply 41 and the second power supply 42, those shown in Table 1 were selected and used. Both electrodes were adjusted and kept at 80 ° C. As shown in Table 1, a 100 μm thick ARTON film (amorphous cyclopolyolefin resin film, manufactured by JSR) was used as the substrate F. The pressure of the discharge space 32 was set to 103 kPa, the mixed gas MG having the following composition was filled in the discharge space 32, the high-frequency electric field shown in Table 1 was applied, and the output density of the first electrode was 7 W / cm.², The output density of the second electrode is 7 W / cm²Was performed, and an ITO film having a thickness of 80 nm was formed on the substrate F film. At that time, the conditions of the power supply and the electrodes were changed as described in Table 1 to change the frequency and the electric field intensity of the electric field formed by the first power supply and the second power supply. Nos. 1 to 17 were produced. The discharge starting electric field intensity of the nitrogen gas in this system was 3.7 kV / mm.
[0222]

Sample No. With respect to Nos. 1 to 17, the discharge state was observed, and the specific resistance, specific resistance, robustness, pencil hardness, and etching characteristics were evaluated. The results are shown in Table 1 below.
[0223]
[Table 1]

[0224]
(result)
The high-frequency electric field strength (V) of the first and second electrodes₁, V₂) And the discharge electric field intensity (IV) of the discharge gas have a relational expression according to the present invention. With respect to Nos. 1 to 12, the discharge conditions were good, an ITO film having a low resistance value was formed, the specific resistance value and the robustness were good, and the pencil hardness was all good. On the other hand, in the case of the sample No. 13 to 17 all have a problem in at least one of the characteristics. Sample No. 1 in which both the first and second high-frequency electric fields were smaller than the discharge starting electric field. In Nos. 15 and 16, discharge did not occur and an ITO film could not be formed (powder-like deposits).
[0225]
Example 2
Using an atmospheric pressure plasma discharge treatment apparatus having the structure shown in FIG. 7, an ITO film was formed on a glass plate as a base material mounted on a moving base.
[0226]
(Preparation of electrode)
<Counter electrode>
Two sets of fixed electrodes to which the gas shown in FIG. 7 can be separately introduced were prepared and used as counter electrodes. As a metal base material, two rectangular tube-shaped hollow members each having a thickness of 7 mm and a length of 50 mm, a width of 600 mm, and a height of 50 mm made of a titanium alloy T64 were produced, and used as second electrodes 436. Separately, a first electrode 435 made of a titanium alloy T64 having a length of 50 mm, a width of 600 mm, and a height of 50 mm and having a hollow inside and a slit 421 (480 mm in length) at the center was produced. A 1 mm gap was formed as a slit so that the surfaces of the second electrode 436 and the first electrode 435 became parallel, and this slit was used as a discharge space 432. The second electrodes 436 are connected to each other by connection. Gas inlets 452 and 453 shown in FIG. 7 were joined to the slit 421 and the discharge space 432 on the electrode.
[0227]
<Moving stand>
Prepare a flat plate with a length of 600 mm, a width of 600 mm, and a thickness of 50 mm covered with an insulator. Attach a screw suitable for the two screw screw tracks of the moving means on both sides on the back side of the flat plate, and rotate the screw. You can move.
[0228]
[Atmospheric pressure plasma discharge treatment equipment]
The gap between the processing space 434 between the bottom surface (upper and lower sides of the paper) of the opposing electrodes (435 and 436) shown in FIG. The first power source 441 shown in Table 2 was connected to the first electrode 435, and the first filter 443 was installed therebetween. Each power supply and each filter were individually grounded.
[0229]
(Preparation of glass plate having transparent conductive film)
In the first power supply 441 and the second power supply 442, the relationship between the high-frequency electric field strength and the discharge start electric field strength is V.₁> IV> V₂Those shown in Table 2 were selected and used so that As the substrate, a soda glass plate having a length of 500 mm, a width of 450 mm, and a thickness of 0.5 mm was used. Three second electrodes 436 are arranged, the discharge space 432 and the processing space 434 of the second electrode 436 are set to a pressure of 104 KPa, the discharge gas G2 is supplied from the gas supply pipe 453 to the discharge space 432, and the transparent conductive film forming gas G1 is supplied to the gas. It was introduced into the slit 521 from the supply pipe 532. The temperature was adjusted so that both electrodes reached 80 ° C. The high-frequency electric field shown in Table 2 is applied from the first power supply 441 and the second power supply 442, and the output density of the first electrode is set to 7 W / cm.², The output density of the second electrode is 7 W / cm²The discharge gas is excited in the discharge space 432 and jetted out in the form of a jet. The transparent conductive film forming gas is discharged from one slit 421 into the processing space and mixed, and energy is discharged from the discharge gas in the plasma state. In response, the transparent conductive film forming gas was excited to be in a plasma state. The base glass plate F is exposed to the transparent conductive film forming gas G ° in the plasma state, and the movable base is reciprocated in the processing space 434 until the film thickness becomes 80 nm to form an ITO film on the base glass plate. A glass plate having a film was prepared. 18-21. The discharge starting electric field intensity of the mixed discharge gas of nitrogen and oxygen was 3.8 kV / mm.
[0230]
The transparent conductive film forming gas G1 and the discharge gas G2 were introduced into the processing space at a ratio of 1:10.
[0231]

Sample No. Preparation of 22
The first power source and the second power source are both set to B1 (V₁= V₂<IV) In addition to the sample No. 1 except that a 10 μH coil was connected and installed in both the first filter and the second filter. Sample No. 18 22. The sample No. No. 22 did not form a film and became a powdery deposit.
[0232]
Sample No. Production of 23 and 24
The second power supply 442 and the second filter 444 were removed from the second electrode 4636 of FIG. 7 and only the ground was grounded, and only the first power supply shown in Table 2 was used. Sample No. 18 23 and 24. The sample No. No. 23 did not form a film and became a powdery deposit.
[0233]
Sample No. For 18 to 24, the discharge state was confirmed, and the specific resistance, robustness, pencil hardness, and pencil hardness were evaluated. The results are shown in Table 2 below.
[0234]
[Table 2]

[0235]
(result)
Sample No. 1 in which a mixed gas of nitrogen and oxygen was used as a discharge gas, and a frequency of a first power supply and a first filter, and a frequency of a second power supply and a second filter suitable for the present invention were installed to form an ITO film. In Nos. 18 to 21, the discharge was performed normally, the ITO film was formed normally, the ITO film having a low resistance was formed, the robustness of the specific resistance was good, and the pencil hardness was all good. Was. On the other hand, the sample No. At 22 (comparison), no discharge was generated at the frequencies of the first power supply and the second power supply, no ITO film was formed, and powdery deposits were formed. Sample No. Samples Nos. 23 and 24 (comparative) used the counter electrode as a ground electrode. In No. 23, application was performed at a high-frequency electric field intensity lower than the electric field intensity at the start of discharge, but no discharge was caused, and as a result, no ITO film was formed. Sample No. In No. 24, the application was performed with an electric field intensity higher than the electric field intensity at the start of discharge. However, although discharge was performed, a good ITO film could not be formed, the specific resistance of the ITO film was high, and the robustness of the specific resistance was poor. And the pencil hardness was also inferior.
[0236]
Example 3
Using an atmospheric pressure plasma discharge treatment apparatus having the structure shown in FIG. 8, an ITO film is formed on a glass plate substrate, and treated with an oxidizing gas using an oxidizing gas treatment chamber. The oxidizing gas treatment was repeated five times to produce a glass plate having an ITO film.
[0237]
(Preparation of electrode)
<Fixed electrode>
Two rectangular cylindrical electrodes coated with a dielectric material similar to those used in Example 1 were formed as a pair, and two parallel electrodes were joined with a 1.5 mm wide slit interposed therebetween to form one fixed electrode 536. And Three sets of the two fixed electrodes 536 were prepared.
[0238]
<Moving stand electrode>
A flat plate of a hollow titanium alloy T64 having a length of 600 mm, a width of 600 mm, a thickness of 50 mm, and a thickness of 7 mm was prepared, and the metal base material of Example 1 or 2 was coated with a dielectric and polished in the same manner. The surface to be the counter electrode was coated with a dielectric, and the dielectric coating had similar properties. On both sides on the back side of the flat plate, screws suitable for the two screw screw tracks of the moving means were attached so that they could be moved by the rotation of the screws, and the movable mount electrode 535 was formed.
[0239]
(Oxidizing gas processing chamber)
The oxidizing gas processing chamber 560 having the gate 519 is provided with two screw screw orbits of a moving means capable of moving the movable gantry electrode 535. After the movable gantry enters the oxidizing gas processing chamber, the following oxidizing gas is introduced and filled through the oxidizing gas inlet.
[0240]
[Atmospheric pressure plasma discharge treatment equipment]
The three fixed electrodes 536 manufactured above are arranged on the same plane (only one is shown in FIG. 8), and the fixed electrodes 536 are disposed between the opposing electrodes (three fixed electrodes 536 and the movable base electrode 535). (Discharge space) 532 was 1.5 mm. The first power source 541 shown in Table 3 was connected to the movable gantry electrode (first electrode) 535, and a first filter 543 was installed therebetween. Each power supply and each filter were individually grounded.
[0241]
(Preparation of glass plate having transparent conductive film)
In the first power supply 541 and the second power supply 542, the relationship between the high-frequency electric field intensity and the discharge start electric field intensity is V.₁> IV> V₂Those shown in Table 3 were selected and used so that As the substrate, a soda glass plate having a length of 500 mm, a width of 450 mm, and a thickness of 0.5 mm was used. The pressure in the discharge space 532 between the three fixed electrodes 536 and the movable gantry electrode 535 is set to 104 KPa, and the following transparent conductive film forming gas MG is mixed with the ITO film forming mixed gas MG, the IZO film forming mixed gas MG, and the FTO. A gas supply pipe 552 was introduced as a mixed gas MG for film formation, and the following high-frequency electric field was applied to form an ITO film, an IZO film, and an FTO film, respectively. The temperature was adjusted to 80 ° C. for both electrodes. The high-frequency electric field shown in Table 3 is applied from the first power supply 541 and the second power supply 542, and the output density of the first electrode is set to 7 W / cm.², The output density of the second electrode is 7 W / cm²A discharge is generated, and the mixed gas in a plasma state is jetted out of the discharge space 521 in a jet state. In the processing space 532, the base glass plate F is exposed to the transparent conductive film forming gas G ° in the plasma state, and once transparent. Each time the conductive film was formed, the movable gantry was moved to an oxidizing gas treatment chamber and exposed to the following oxidizing gas for 5 minutes. This operation was repeated until the film thickness reached 100 nm, and a glass plate substrate having an ITO film, an IZO film, and an FTO film was produced, respectively. 25 to 34. The electric field intensity at the start of discharge of nitrogen gas in this system was 3.7 kV / mm.
[0242]

Sample No. Production of 35-41
Combinations of the first power supply and the second power supply (high-frequency electric field, V₁= V₂> IV, V₁= V₂<IV), a sample was prepared under conditions such as non-use of the second power source, and a 100 nm ITO film, an IZO film, and an FTO film were formed on a glass plate substrate. 35 to 41. The sample No. Nos. 36, 38 and 41 did not form a film, and became powdery deposits.
[0243]
Sample No. With respect to 25 to 41, the discharge state was observed, and the specific resistance, robustness of specific resistance, pencil hardness, and etching characteristics were evaluated. The results are shown in Table 3 below.
[0244]
[Table 3]

[0245]
(result)
By forming an ITO film by performing a plasma discharge treatment at a frequency and an electric field strength suitable for the present invention, and performing an oxidizing gas treatment after forming a transparent conductive film, the film is dense, has low resistance, has excellent robustness, and is excellent. It was possible to form an ITO film and an IZO film and an FTO film having excellent etching characteristics (Sample Nos. 25 to 34). On the other hand, the relationship between the applied high-frequency electric field intensity and the discharge starting electric field intensity is V₁= V₂Although samples 35, 37 and 40 with> IV discharged, only an ITO film, an IZO film and an FTO film having high specific resistance, poor robustness, low hardness and poor etching characteristics were obtained. Also, IV> V₁= V₂Sample No. In No. 38, no discharge occurred and a film could not be formed. Although discharge occurred in the sample 31 in which the second power supply was not used, the IZO film could not be formed, and the sample No. 31 was not used. In Nos. 36 and 41, no discharge occurred and no FTO film could be formed.
[0246]
【The invention's effect】
According to the present invention, a high-quality transparent conductive film that can achieve high-density plasma, has a low resistance value, does not deteriorate in specific resistance even when left under high-humidity and high-temperature conditions, has high hardness, and has excellent etching performance And a base material having a high-quality and high-performance transparent conductive film manufactured by the method can be provided at low cost.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an example of an atmospheric pressure plasma discharge processing apparatus useful for the present invention.
FIG. 2 is a perspective view showing an example of the structure of a conductive metal base material of a roll rotating electrode shown in FIG. 1 and a dielectric material coated thereon.
FIG. 3 is a perspective view showing an example of a structure of a conductive metal base material of a rectangular cylindrical electrode and a dielectric material coated thereon.
FIG. 4 is a schematic view showing an example of an atmospheric pressure plasma discharge processing apparatus useful for the present invention.
FIG. 5 is a schematic view showing an example of an atmospheric pressure plasma discharge processing apparatus useful for the present invention.
FIG. 6 is a schematic view showing an example of an atmospheric pressure plasma discharge processing apparatus useful for the present invention.
FIG. 7 is a schematic view showing an example of an atmospheric pressure plasma discharge processing apparatus useful for the present invention.
FIG. 8 is a schematic diagram showing an example of an atmospheric pressure plasma discharge processing apparatus in which an oxidizing processing chamber is added to FIG. 4 useful for the present invention.
[Explanation of symbols]
32 ° discharge space
35 ° roll rotating electrode
36 square tube fixed electrode group
41 1st power supply
42 second power supply
43 1st filter
44 second filter

Claims (51)

At atmospheric pressure or a pressure near that, a gas containing a transparent conductive film forming gas is supplied to the discharge space,
Exciting the gas by applying a high-frequency electric field to the discharge space, in the method of forming a transparent conductive film to form a thin film on the substrate by exposing the substrate to the excited gas,
The high-frequency electric field is obtained by superimposing a first high-frequency electric field and a second high-frequency electric field;
It said first of said second high-frequency electric field than the frequency omega ₁ of the high-frequency electric field frequency omega ₂ is high,
The intensity V ₁ of the first high-frequency electric _field, the relationship between the intensity IV of the second high frequency electric field intensity V _2, and a discharge start electric field,
V ₁ ≧ IV> V ₂
Or satisfying V ₁ > IV ≧ V ₂ ,
A method for forming a transparent conductive film, comprising: The method according to claim 1, wherein the discharge space includes a first electrode and a second electrode facing each other. The method according to claim 1, wherein an output density of the second high-frequency electric field is 50 W / cm ² or less. The power density of the second high-frequency electric field, the method of forming the transparent conductive film according to claim 3, characterized in that at 20W / cm ² or less. The method for forming a transparent conductive film according to claim 1, wherein an output density of the first high-frequency electric field is 1 W / cm ² or more. The power density of the first high-frequency electric field, the method of forming the transparent conductive film according to claim 5, characterized in that 50 W / cm ² or less. The method for forming a transparent conductive film according to claim 1, wherein at least the second high-frequency electric field is a sine wave. The voltage for forming the first high-frequency electric field is applied to the first electrode, and the voltage for forming the second high-frequency electric field is applied to the second electrode. 8. The method for forming a transparent conductive film according to any one of 7. The method for forming a transparent conductive film according to any one of claims 1 to 8, wherein 90 to 99.9% by volume of the total gas supplied to the discharge space is a discharge gas. The method for forming a transparent conductive film according to claim 9, wherein the discharge gas contains 50 to 100% by volume of nitrogen gas. 11. The discharge gas according to claim 10, wherein the discharge gas contains 50 to 100% by volume of a mixed gas of nitrogen and oxygen or a nitrogen gas having a volume ratio of nitrogen gas: oxygen gas of 50:50 to 100: 0. The method for forming a transparent conductive film according to the above. The method according to claim 11, wherein the discharge gas contains less than 50% by volume of a rare gas. The method for forming a transparent conductive film according to claim 1, wherein an output density of the second high-frequency electric field is 1 W / cm ² or more. 14. The method according to claim 13, wherein an output density of the first high-frequency electric field is 1 W / cm ² or more. The transparent conductive film according to any one of claims 1 to 14, wherein the transparent conductive film forming gas contains at least one selected from an organometallic compound, a metal halide, and a metal hydride compound. Forming method. The said organometallic compound contains at least one compound selected from the group consisting of an organic silicon compound, an organic titanium compound, an organic tin compound, an organic zinc compound, an organic indium compound and an organic aluminum compound, according to claim 15, wherein A method for forming a transparent conductive film. The method according to claim 16, wherein the organometallic compound is represented by the following general formula (I).
General formula (I) R ¹ _x MR ² _y R ³ _z
In the formula, M is a metal, R ¹ is an alkyl group, R ² is an alkoxy group, R ³ is a β-diketone complex group, a β-ketocarboxylic ester complex group, a β-ketocarboxylic acid complex group, and a ketooxy group (ketooxy complex group). Where x + y + z = m, x = 0 to m, y = 0 to m, and z = 0 to m, where m is the valence of the metal M. Organometallic compounds represented by the general formula (I), at least one of R ^2, i.e., the method of forming the transparent conductive film according to claim 17, characterized in that having an alkoxy group. When the organometallic compound represented by the general formula (I) has at least one R ³ , that is, a β-diketone complex group, a β-ketocarboxylic ester complex group, a β-ketocarboxylic acid complex group, and a ketooxy group (ketooxy complex group) The method for forming a transparent conductive film according to claim 17, wherein the method has a group selected from the group consisting of: The metal of M in the organometallic compound represented by the general formula (I) is indium (In), tin (Sn), zinc (Zn), zirconium (Zr), antimony (Sb), aluminum (Al), gallium. The method for forming a transparent conductive film according to any one of claims 16 to 19, wherein the method is at least one selected from (Ga) and germanium (Ge). The method for forming a transparent conductive film according to claim 1, wherein the gas contains a reducing gas. 22. The method according to claim 21, wherein the reducing gas is hydrogen. The method for forming a transparent conductive film according to any one of claims 1 to 22, wherein after forming the transparent conductive film, the transparent conductive film is exposed to an oxidizing gas atmosphere. 24. The method according to claim 23, wherein the formation of the transparent conductive film and the exposure to the oxidizing gas atmosphere are performed alternately. A substrate comprising a transparent conductive film formed by the method for forming a transparent conductive film according to claim 1. At atmospheric pressure or a pressure close to the atmospheric pressure, a gas containing a discharge gas including a transparent conductive film forming gas and a nitrogen gas is supplied to the discharge space,
Exciting the gas by applying a high-frequency electric field to the discharge space, in the method of forming a transparent conductive film to form a thin film on the substrate by exposing the substrate to the excited gas,
The high-frequency electric field is obtained by superimposing a first high-frequency electric field and a second high-frequency electric field;
It said first of said second high-frequency electric field than the frequency omega ₁ of the high-frequency electric field frequency omega ₂ is high,
The intensity V ₁ of the first high-frequency electric _field, the relationship between the intensity IV of the second high frequency electric field intensity V _2, and a discharge start electric field,
V ₁ ≧ IV> V ₂
Or satisfying V ₁ > IV ≧ V ₂ ,
A method for forming a transparent conductive film, comprising: The method according to claim 26, wherein the discharge space includes a first electrode and a second electrode facing each other. 28. The method according to claim 26, wherein an output density of the second high-frequency electric field is 50 W / cm < ² > or less. The method for forming a transparent conductive film according to claim 28, wherein an output density of the second high-frequency electric field is 20 W / cm ² or less. The method for forming a transparent conductive film according to any one of claims 26 to 29, wherein the power density of the first high-frequency electric field is 1W / cm ² or more. The power density of the first high-frequency electric field, the method of forming the transparent conductive film according to any one of claims 26 to 30, characterized in that it is 50 W / cm ² or less. The method for forming a transparent conductive film according to any one of claims 26 to 31, wherein at least the second high-frequency electric field is a sine wave. 27. A voltage for forming the first high-frequency electric field is applied to the first electrode, and a voltage for forming the second high-frequency electric field is applied to the second electrode. 32. The method for forming a transparent conductive film according to any one of the items 32. The method for forming a transparent conductive film according to any one of claims 26 to 33, wherein 90 to 99.9% by volume of the total gas supplied to the discharge space is the discharge gas. The method for forming a transparent conductive film according to claim 34, wherein the discharge gas contains 50 to 100% by volume of nitrogen gas. The method for forming a transparent conductive film according to claim 34 or 35, wherein the discharge gas contains less than 50% by volume of a rare gas. 27. The discharge gas according to claim 26, wherein a volume ratio of nitrogen gas: oxygen gas is 50:50 to 100: 0, and a mixed gas of nitrogen and oxygen or nitrogen gas is 50 to 100% by volume. 36. The method for forming a transparent conductive film according to any one of 36. The power density of the second high-frequency electric field, the method of forming the transparent conductive film according to any one of claims 26 to 37, characterized in that at 1W / cm ² or more. Wherein the frequency omega ₁ is the method of forming the transparent conductive film according to any one of claims 26 to 38, characterized in that at 200kHz or less. The frequency omega ₂ is a method of forming the transparent conductive film according to any one of claims 26-39, characterized in that at least 800 kHz. 41. The transparent conductive film according to any one of claims 26 to 40, wherein the transparent conductive film forming gas contains at least one selected from an organometallic compound, a metal halide, and a metal hydride compound. Forming method. The organic metal compound, an organic silicon compound, an organic titanium compound, an organic tin compound, an organic zinc compound, an organic indium compound and at least one compound selected from an organic aluminum compound according to claim 41 characterized by the above-mentioned. A method for forming a transparent conductive film. 43. The method according to claim 42, wherein the organometallic compound is represented by the following general formula (I).
General formula (I) R ¹ _x MR ² _y R ³ _z
In the formula, M is a metal, R ¹ is an alkyl group, R ² is an alkoxy group, R ³ is a β-diketone complex group, a β-ketocarboxylic ester complex group, a β-ketocarboxylic acid complex group, and a ketooxy group (ketooxy complex group). Where x + y + z = m, x = 0 to m, y = 0 to m, and z = 0 to m, where m is the valence of the metal M. The method for forming a transparent conductive film according to claim 43, wherein the organometallic compound represented by the general formula (I) has at least one R ² , that is, an alkoxy group. When the organometallic compound represented by the general formula (I) is at least one R ³ , that is, a β-diketone complex group, a β-ketocarboxylic ester complex group, a β-ketocarboxylic acid complex group, and a ketooxy group (ketooxy complex group) The method for forming a transparent conductive film according to claim 43, wherein the method has a group selected from the group consisting of: The metal of M in the organometallic compound represented by the general formula (I) is indium (In), tin (Sn), zinc (Zn), zirconium (Zr), antimony (Sb), aluminum (Al), gallium. The method for forming a transparent conductive film according to any one of claims 43 to 45, wherein the transparent conductive film is at least one selected from (Ga) and germanium (Ge). The method for forming a transparent conductive film according to any one of claims 26 to 46, wherein the gas contains a reducing gas. The method for forming a transparent conductive film according to claim 47, wherein the reducing gas is hydrogen. The method for forming a transparent conductive film according to any one of claims 26 to 48, wherein after forming the transparent conductive film, the transparent conductive film is exposed to an oxidizing gas atmosphere. 50. The method according to claim 49, wherein the formation of the transparent conductive film and the exposure to the oxidizing gas atmosphere are performed alternately. A substrate comprising a transparent conductive film formed by the method for forming a transparent conductive film according to claim 26.

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