JP4258239B2 - Method for manufacturing organic EL element and method for manufacturing organic EL panel - Google Patents

Description

【００４０】
アノード１３，１３，…及びトランジスタ２１，２１，…の形成後、ＰＶＤ法及びＣＶＤ法等といった成膜工程、フォトリソグラフィー法等といったマスク工程、エッチング法といった薄膜の形状加工工程を行うことによって、アノード１３，１３，…を囲繞するように網目状の保護絶縁膜１８を形成する。保護絶縁膜１８を形成することによって、保護絶縁膜１８に囲繞された囲繞領域１９，１９，…が形成され、各囲繞領域１９においてアノード１３が露出している（図３（ｂ））。
【００４１】
次いで、透明基板１２の表面１２ａ側を即ちアノード１３，１３，…及び保護絶縁膜１８の表面を洗浄する。洗浄としては、大気圧未満の減圧下における酸素プラズマ洗浄であっても良いし、紫外線／オゾン洗浄であっても良い。その後、アノード１３，１３，…及び保護絶縁膜１８の表面、透明基板１２の裏面、その他全体を純水で洗浄する。次いで、透明基板１２に例えば窒素ガスといった不活性ガスを吹き付けて、透明基板１２を乾燥させる。
【００４２】
次いで、フッ素を含む官能基を有したシラン化合物、特にシラン化合物の中でも、フッ素を含む官能基を有したシラザン化合物からなる膜を透明基板１２の表面１２ａ側一面にコーティングする。具体的には、フッ素を含む官能基を有したシラザン化合物を含有した溶液（以下、シラザン系溶液という。）に透明基板１２を浸漬し、その後透明基板１２を引き上げることによって、透明基板１２の表面１２ａ側一面にシラザン系溶液を塗布する（ディップコート法）。
【００４３】
ここで、「フッ素を含む官能基を有したシラザン化合物」とは、Ｓｉ−Ｎ−Ｓｉ結合を有し、Ｎ又は／及びＳｉにフッ素を含む官能基が結合したものであり、例えば次の一般式（１）で表すオリゴマー又はポリマーが挙げられる。
ＲｆＳｉ（ＮＨ）_3/2 …（１）
一般式（１）においてＲｆは、フッ素を含む官能基である。
「フッ素を含む官能基」としては、フルオロアルキル基があり、例えば、次の一般式（２）〜（１９）で表す官能基が挙げられる。
−（ＣＨ₂）_a（ＣＦ₂）_bＣＦ₃ …（２）
−（ＣＨ₂）_a（ＣＦ₂）_bＣＦ（ＣＦ₃）₂ …（３）
−（ＣＨ₂）_a（ＣＦ₂）_bＣ（ＣＦ₃）₃ …（４）
−（ＣＦ₂）_aＣＦ₃ …（５）
−（ＣＦ₂）_aＣＦ（ＣＦ₃）₂ …（６）
−（ＣＦ₂）_aＣ（ＣＦ₃）₃ …（７）
−（ＣＦ₂）_a（Ｃ（ＣＦ₃）₂）_bＣＦ₃ …（８）
−（ＣＦ₂）_a（Ｃ（ＣＦ₃）₂）_bＣＦ（ＣＦ₃）₂ …（９）
−（ＣＦ₂）_a（Ｃ（ＣＦ₃）₂）_bＣ（ＣＦ₃）₃ …（１０）
−（ＣＦ₂）_a（Ｃ（ＣＦ₃）₂）_b（ＣＦ₂）_cＣＦ₃ …（１１）
−（ＣＦ₂）_a（Ｃ（ＣＦ₃）₂）_b（ＣＦ₂）_cＣＦ（ＣＦ₃）₂ …（１２）
−（ＣＦ₂）_a（Ｃ（ＣＦ₃）₂）_b（ＣＦ₂）_cＣ（ＣＦ₃）₃ …（１３）
−（Ｃ（ＣＦ₃）₂）_aＣＦ₃ …（１４）
−（Ｃ（ＣＦ₃）₂）_aＣＦ（ＣＦ₃）₂ …（１５）
−（Ｃ（ＣＦ₃）₂）_aＣ（ＣＦ₃）₃ …（１６）
−（Ｃ（ＣＦ₃）₂）_a（ＣＦ₂）_bＣＦ₃ …（１７）
−（Ｃ（ＣＦ₃）₂）_a（ＣＦ₂）_bＣＦ（ＣＦ₃）₂ …（１８）
−（Ｃ（ＣＦ₃）₂）_a（ＣＦ₂）_bＣ（ＣＦ₃）₃ …（１９）
一般式（２）〜（１９）においてａ，ｂ，ｃはいずれも整数である。
【００４４】
シラザン系溶液の溶媒としては、フッ素系溶剤が挙げられる。
【００４５】
ここでは、シラザン化合物として、次の一般式（２０）及び化学構造式（２１）で表せるシラザンオリゴマー（ＫＰ−８０１Ｍ：信越化学工業株式会社製）を用いる。そして、上述のディップコート工程においては、このシラザンオリゴマーを溶質としてｍ−キシレンヘキサフロライド溶媒に溶かしたシラザン系溶液（濃度３wt％）に透明基板１２を約一分間浸漬する。
Ｃ₈Ｆ₁₇Ｃ₂Ｈ₄Ｓｉ（ＮＨ）_3/2 …（２０）
【化１】

【００４６】
次いで、透明基板１２に例えば窒素ガスといった不活性ガスを吹き付けて、シラザン系溶液の溶媒を蒸発させることで、シラザン化合物がアノード１３，１３，…及び保護絶縁膜１８の表面に堆積した状態となる。
【００４７】
次いで、透明基板１２を１０〜３０分間放置すると、雰囲気中の水分によってシラザン化合物が加水分解・重合するとともに保護絶縁膜１８と化学的に結合する。これにより、図３（ｃ）に示すように、フッ素を含む官能基が結合した重合体からなる濡れ性可変層１４’が、アノード１３，１３，…及び保護絶縁膜１８全体を覆うように一面に成膜される。濡れ性可変層１４’に含まれる重合体は、次の一般式（２２）で表される。
【化２】

【００４８】
一般式（２２）において、Ｒｆは上述したようにフッ素を含む官能基であって撥液性を示す官能基であり、Ｘはシラザン化合物と結合したアノード１３の原子若しくは原子団、保護絶縁膜１８の原子若しくは原子団、アノード１３若しくは保護絶縁膜１８の表面と結合したシラザン化合物の一部の原子若しくは原子団、又は、化学構造式（２１）におけるＮＨ基を置換した基を構成する原子若しくは原子団のいずれかであり、ｎは１００以上の整数である。シラザン化合物が一般式（２０）で表されるシラザンオリゴマーの場合には、ＲｆはＣ₈Ｆ₁₇Ｃ₂Ｈ₄となり、ＸがＯとなる。シラザン化合物は活性が高く、アノード１３，１３，…及び保護絶縁膜１８にも吸着しやすいから、濡れ性可変層１４’がアノード１３，１３，…及び保護絶縁膜１８の表面に化学吸着した状態で成膜される。従って、濡れ性可変層１４’においては、シラザン化合物の単分子ユニットにおける主鎖であるＲｆ−Ｓｉ−Ｘ−基又はＲｆ−Ｓｉ−基が、アノード１３，１３，…及び保護絶縁膜１８の表面に対して略垂直方向に配列するとともに隣接する単分子ユニットのＳｉが、アノード１３，１３，…及び保護絶縁膜１８の表面に沿った方向に対して加水分解により酸素をエーテル結合の状態で重合されている。つまり、シラザン化合物は、アノード１３，１３，…及び保護絶縁膜１８の表面の面方向に重合されるとともに、アノード１３，１３，…及び保護絶縁膜１８の表面に形成された、単分子ユニットにおける主鎖であるＲｆ−Ｓｉ−Ｘ−基又はＲｆ−Ｓｉ−基の上方に、更に単分子ユニットにおける主鎖Ｒｆ−Ｓｉ−Ｘ−基又はＲｆ−Ｓｉ−基が積み重なるということが殆どなくなる。このため、濡れ性可変層１４’の厚さは、実質的に単分子ユニットにおける主鎖（ここでは重合体としての側鎖に相当。）であるＲｆ−Ｓｉ−Ｘ−基又はＲｆ−Ｓｉ−基の長さに等しくなる。またこの濡れ性可変層１４’は、各単分子ユニットにおける主鎖の中のフッ素を含む官能基Ｒｆが濡れ性可変層１４’の表面側に配置するように重合されているから、表面では各官能基Ｒｆの撥液性によって有機化合物含有液に対して撥液性を示す。
【００４９】
次いで、透明基板１２を放置した後に、透明基板１２の表面１２ａ側をｍ−キシレンヘキサフロイド液ですすぐことで、アノード１３，１３，…及び保護絶縁膜１８の表面に堆積した未反応のシラザン化合物を洗い流す。このとき、アノード１３，１３，…では、中心線平均粗さＲａが０．５ｎｍ以上ＥＬ層１５の厚さの半分以下と凹凸の差が大きく、一画素当たりのアノード１３の表面積が十分大きいので、アノード１３表面上の濡れ性可変層１４’が塗布された実面積も大きい。
【００５０】
次いで、図３（ｄ）に示すように、透明基板１２にフォトマスク基板４０を対向させて更に後述するフォトマスク基板４０の光触媒膜４３に活性光線を照射することで生じる触媒作用により濡れ性可変層１４’がパターン膜１４となる。活性光線としては、可視光線、紫外線、赤外線等があるが、後述する光触媒膜４３を励起するものである。
【００５１】
ここで、フォトマスク基板４０について説明する。フォトマスク基板４０は活性光線を透過する透明基板４１を有し、この透明基板４１の一方の面４１ａには、囲繞領域１９，１９，…に対応するようにマトリクス状に配列された複数の開口部を有するマスク４２が網目状に形成され、約０．２μｍ厚の光触媒膜４３がマスク４２全体を被覆するように一方の面４１ａ上に成膜されている。つまり、マスク４２は、保護絶縁膜１８に対応するパターンに形成されている。マスク４２によって囲繞される開口部の開口面積は、囲繞領域１９の面積よりやや大きくなっている。
【００５２】
マスク４２は活性光線を反射したり、吸収したりし、活性光線を透過しない。光触媒膜４３は、酸化チタン（ＴｉＯ₂）、酸化亜鉛（ＺｎＯ）、酸化スズ（ＳｎＯ₂）、チタン酸ストロンチウム（ＳｒＴｉＯ₃）、酸化タングステン（ＷＯ₃）、酸化ビスマス（Ｂｉ₂Ｏ₃）及び酸化鉄（Ｆｅ₂Ｏ₃）の中から選ばれる一種又は二種以上の物質で形成されている。ここでは、酸化チタンを光触媒膜４３として用いる。酸化チタンは、アナターゼ型とルチル型があり本発明では何れも使用することができるが、アナターゼ型の酸化チタンは励起波長が３８０ｎｍ以下であるからより好ましい。
【００５３】
以上のようなフォトマスク基板４０の上方に活性光線を照射する光源を配置し、透明基板４１の裏面４１ｂから面４１ａに向けて活性光線を照射する。マスク４２では活性光線が遮蔽されるが、マスク４２によって囲繞された開口部を通過してマスク４２の無い部分では光触媒膜４３に照射される。従って、濡れ性可変層１４’のうちマスク４２に重なる領域つまり保護絶縁膜１８上の領域には、活性光線が入射しないが、それぞれの囲繞領域１９に重なる領域には活性光線が入射する。
活性光線が光触媒膜４３を透過する際に活性酸素種（・ＯＨ）が生成され、この活性酸素種が濡れ性可変層１４’と化学反応を引き起こす。濡れ性可変層１４’のうち囲繞領域１９，１９，…に重なった領域には、光触媒膜４３を透過した活性酸素種が到達し、保護絶縁膜１８に重なった領域には、マスク４２によって活性光線が遮蔽されるから活性酸素種が届かない。このように光触媒の作用は、光触媒膜４３に活性光線が入射することによって活性酸素種が発生し、発生した活性酸素種がフォトマスク基板４０と濡れ性可変層１４’との間の気相を拡散し、濡れ性可変層１４’に到達した活性酸素によって濡れ性可変層１４’の化学構造を変化させる。なお、マスク４２によって囲繞される開口部の開口面積が囲繞領域１９の面積よりもやや大きいため、それぞれの囲繞領域１９よりもやや外側にも活性酸素種が到達する。
【００５４】
濡れ性可変層１４’のうちマスク４２と重ならない領域は、光触媒の作用により生成された活性酸素種（・ＯＨ）により撥液性を示すＲｆ基が脱離して、親水性を示す水酸基に置換され、一般式（２３）に示すようになる。
【化３】

この領域が親液性領域１４ａである。親液性領域１４ａは、フッ素を含む官能基（上記Ｒｆ）が分解・脱離し、水酸基に置換されるために、有機化合物含有液に対して親液性を示し、後述するＥＬ層１５を構成する材料が含まれる液体をはじくことなくこの液体を親液性領域１４ａの表面に均一に成膜することが可能になる。このとき、アノード１３，１３，…では、中心線平均粗さＲａが０．５ｎｍ以上ＥＬ層１５の厚さの半分以下と凹凸の差が大きく、一画素当たりのアノード１３の表面積が十分大きいので、アノード１３表面上の濡れ性可変層１４’が塗布された実面積も大きい。
【００５５】
更に、親液性領域１４ａにおいては、珪素と酸素からなる重合体における主鎖がアノード１３，１３，…の表面に沿った状態で形成され、且つ、撥液性を示すフッ素を含む官能基が水酸基に置換されるため、膜厚も単分子ユニットにおける主鎖（ここでは重合体としての側鎖に相当。）であるＨＯ−Ｓｉ−Ｘ−基又はＨＯ−Ｓｉ−基の長さに等しく、１ｎｍ以下と非常に薄くすることができる。そのため、活性酸素種が生成された領域であるアノード１３，１３，…上では、パターン膜１４の膜厚が非常に薄くなり、親液性領域１４ａ自体が正孔等の電荷の注入、輸送に支障をきたすことはほとんどない。
そして、濡れ性可変層１４’のうちマスク４２と重なる領域には、活性酵素が到達しないから化学変化が起きず、ＥＬ層１５を構成する材料が含まれる液体に対して依然撥液性を示す。この領域が、撥液性領域１４ｂである。撥液性領域１４ｂは、親液性領域１４ａと連続して形成されているとともに親液性領域１４ａよりもほぼフッ素を含む官能基Ｒｆの分だけ厚い。
【００５６】
以上のように濡れ性可変層１４’を部分的に露光することによってパターン膜１４を形成した後、それぞれの囲繞領域１９内にＥＬ層１５をアノード１３の中心線平均粗さＲａの二倍以上の膜厚となるように成膜する。ＥＬ層１５，１５，…の成膜は、液滴吐出技術（インクジェット技術）を応用して行う。つまり、図４（ｅ）に示すように、ＥＬ層１５の構成材料を含有した有機化合物含有液を吐出することのできるノズル７０を透明基板１２に対向させて、駆動装置によって透明基板１２に対して相対的にノズル７０を水平面に沿って移動させつつ、ノズル７０が囲繞領域１９上に位置した時にノズル７０から有機化合物含有液を液滴として一回又は複数回吐出する。これにより、有機化合物含有液の液滴が囲繞領域１９内においてパターン膜１４上に着弾する。なお、有機化合物含有液を赤、緑、青の色ごとに準備し、ＥＬ層１５，１５，…の色を塗り分けても良い。
【００５７】
着弾した液滴が親液性領域１４ａで広がって膜になり、そしてその膜が固化することによって、ＥＬ層１５が形成される。パターン膜１４は囲繞領域１９内において親液性領域１４ａとなっているため、着弾した液滴が濡れやすいとともに滲みやすく、有機化合物含有液が囲繞領域１９内全体にいきわたる。
【００５８】
特に、アノード１３，１３，…の中心線平均粗さＲａが０．５ｎｍ以上ＥＬ層１５の厚さの半分以下に粗く形成されているため、親液性領域１４ａの表面積が広くなって、親液性領域１４ａに液滴が濡れやすい。これは以下のように説明することができる。
【００５９】
固体表面に対する液滴の濡れは、二つの因子によって決まる。一つは、固体を構成する物質とその表面を濡らす液滴との組み合わせによって決まる化学的因子であり、もう一つは、固体表面のミクロな凹凸構造の因子である。
平らな面における接触角θは、固体と液滴の表面張力、及び固体と液滴との界面張力の釣り合いによって決まり、次のYoungの式が成り立つ。
γ_s＝γ_SL＋γ_LＣＯＳθ …（２４）
ここで、γ_Sは固体の表面張力、γ_Lは液滴の表面張力、γ_SLは固体と液体との界面張力である。表面が平らでなく微細な凹凸構造を有している、マクロ的な面積に比べ実表面積は大きくなる。表面積がｒ倍大きくなったとすると式（２４）中の固体の表面張力、固体と液体との界面張力のみにｒを乗じる必要がある。
ＣＯＳθ_f＝ｒ（γ_S−γ_SL）／γ_L …（２５）
ここで、θ_fは粗い表面上での接触角である。ｒは常に１より大きな正の数であるから、ＣＯＳθが正であるかつまりθ＜９０°であるか、ＣＯＳθが負であるかつまりθ＞９０°であるかによって、ＣＯＳθ_fは大きな正又は負の値となる。つまり、表面が粗くなることによって濡れる表面は、より濡れるようになり、はじく表面はよりはじくようになる。
以上により、親液性領域１４ａがより濡れるようになる。
【００６０】
親液性領域１４ａは、０ｎｍより長く１ｎｍ以下の厚さであり、アノード１３の中心線平均粗さＲａが０．５ｎｍ以上ＥＬ層１５の厚さの半分以下と凹凸の差が大きいので、親液性領域１４ａの表面は凹凸があり、平滑でない状態となっている。したがってＥＬ層１５はパターン膜１４の凹凸に噛み合うように成膜されるのでＥＬ層１５とパターン膜１４との間で剥離が生じにくい。加えて、囲繞領域１９よりやや外側にも活性光線が入射して囲繞領域１９よりも広い親液性領域１４ａが形成されているから、ＥＬ層１５となる液滴の親液性領域１４ａでの接触角が低くなるので有機化合物含有液が確実に囲繞領域１９内全体にいきわたる。そのため、ＥＬ層１５が均等な厚さで成膜されるとともに、ＥＬ層１５とパターン膜１４との間に剥離が生じにくくなり、不良の発生率を抑えることができる。さらに、それぞれの親液性領域１４ａの周囲は撥液性領域１４ｂとなっているため、有機化合物含有液が撥液性領域１４ｂに滲むことがない。そのため、隣り合う二つの画素の有機化合物含有液同士が混ざり合うことがない。したがって、常に均等な厚さでＥＬ層１５，１５，…を成膜することができ、隣り合う二つの画素が互いに異なる発光色の有機化合物含有液の場合に色純度の高い発色ができる。
【００６１】
なお、ＥＬ層１５が積層構造である場合には、それぞれの層について有機化合物含有液を準備し、囲繞領域１９内にそれぞれの有機化合物含有液を順にノズルで吐出することでそれぞれの層を積層していく。例えば、ＥＬ層１５が正孔注入層、狭義の発光層からなる二層構造の場合には、正孔注入層の有機化合物含有液（正孔注入層を構成する有機化合物（例えば、導電性高分子であるＰＥＤＯＴ（ポリチオフェン））と、ドーパントであるＰＳＳ（ポリスチレンスルホン酸））が水系溶媒に分散した分散液）を各囲繞領域１９内に吐出することで正孔注入層を成膜し、次いで、狭義の発光層の有機化合物含有液（ポリフルオレン系発光材料が例えばトルエン、キシレン、テトラリンといった有機溶媒に溶解した溶液）を各囲繞領域１９内に吐出することでＥＬ層１５を成膜する。この場合でも、パターン膜１４のうち各親液性領域１４ａでは、正孔注入層の有機化合物含有液がなじみ、撥液性領域１４ｂでは正孔注入層の有機化合物含有液がはじかれる。
【００６２】
次いで、窒素雰囲気中でホットプレートによる乾燥、又は、真空中でのシーズヒータによる乾燥を行って、残留した溶媒を除去する。次いで、蒸着やスパッタ法等のＰＶＤ法及びＣＶＤ法といった成膜方法によって、ＥＬ層１５，１５，…を被覆するようにしてカソード１６を一面に成膜する（図４（ｅ））。ＥＬ層１５は囲繞領域１９内全体にいきわたって形成されているから、カソード１６が直接アノード１３に接触することもなく、カソード１６とアノード１３がショートすることがない。カソード１６の成膜後、封止樹脂、封止ガラスといった封止材でこれら有機ＥＬ素子１１，１１，…を封止するが、特にメタルキャップ、ガラス等の封止基板に紫外線硬化樹脂又は熱硬化性接着剤を塗布して、その封止基板をカソード１６側に貼り合わせるのが望ましい。
【００６３】
以上のように製造された有機ＥＬ表示パネル１０では、画素回路が信号線５１及び走査線５２を介して入力した信号に従って有機ＥＬ素子１１に電流を流す。有機ＥＬ素子１１では、アノード１３からＥＬ層１５へ正孔が注入され且つカソード１６からＥＬ層１５へ電子が注入されることで、電流が流れる。そして、ＥＬ層１５において正孔及び電子が輸送されて、ＥＬ層１５にて正孔及び電子が再結合することによってＥＬ層１５で発光する。アノード１３，１３，…及び透明基板１２が透明であるため、ＥＬ層１５で発した光は透明基板１２の裏面１２ｂから出射し、裏面１２ｂが表示面となる。
【００６４】
以上のように、本実施の形態では、シラザン化合物を加水分解・重合させることで濡れ性可変層１４’を成膜し、珪素と酸素で構成された重合体としての主鎖がアノード１３，１３，…及び保護絶縁膜１８の表面に沿った状態で全面に形成され、各囲繞領域１９内において親液性領域１４ａの実質的な厚さが、濡れ性可変層１４’の単分子ユニットにおける主鎖からフッ素を含む官能基Ｒｆを除く厚さとなり非常に薄い。従って、アノード１３とＥＬ層１５との間にパターン膜１４が介在してもパターン膜１４の絶縁性を無視することができ、アノード１３からＥＬ層１５へ正孔が注入されることが阻害されない。アノード１３，１３，…では、中心線平均粗さＲａが０．５ｎｍ以上ＥＬ層１５の厚さの半分以下と凹凸の差が大きいために濡れ性可変層１４’が塗布された実面積も大きいので、必然的に濡れ性可変層１４’とＥＬ層１５との接触面積が大きくなる。したがって濡れ性可変層１４’からＥＬ層１５への正孔を注入する実面積も大きいので、より輝度（ｃｄ／ｍ²）を向上することができる。
【００６５】
また、濡れ性可変層１４’を成膜する前に酸素プラズマ洗浄又は紫外線／オゾン洗浄を行い、その後更に純水で洗浄するから、撥液性を有する非常に薄い濡れ性可変層１４’を簡単に成膜することができる。特に、純水で洗浄したため、保護絶縁膜１８上に撥液性の濡れ性可変層１４’を確実に成膜することができる。これは、純水で洗浄しなかった場合には保護絶縁膜１８上に撥液性の濡れ性可変層１４’を充分に成膜することができないこともあるので、純水洗浄によって保護絶縁膜１８の表層に付着させた水分子でシラザン化合物の加水分解重合反応を起させている。
【００６６】
また、本実施形態では、濡れ性可変層１４’内に光触媒を含有させないで、フォトマスク基板４０を通じて濡れ性可変層１４’に活性酸素種を照射することで、濡れ性可変層１４’を部分的に反応させている。濡れ性可変層１４’のうち活性光線の照射された領域が親液性領域１４ａになり、アノード１３からＥＬ層１５へ正孔が注入されることは阻害されないとともに、パターン膜１４がＥＬ層１５に化学的に影響を与えることもない。
【００６７】
また、濡れ性可変層１４’のうち活性光線の照射された領域が親液性領域１４ａになり、特に親液性領域１４ａ内でもアノード１３に重なっている部分は中心線平均粗さＲａが０．５ｎｍ以上ＥＬ層１５の厚さの半分以下となっていることからより濡れやすいから、ＥＬ層１５が囲繞領域１９全体にいきわたって滲みやすい。これによりＥＬ層１５が囲繞領域１９全体にいきわたって均一に成膜されているから、アノードとカソードの間でショートが生じない。また、ＥＬ層１５とパターン膜１４との間に剥離が生じにくいから、発光したＥＬ層１５にダークスポットが発生しにくい。
【００６８】
なお、上述の説明では、ＥＢ蒸着法によってアノード１３を形成することによって中心線平均粗さＲａが０．５ｎｍ以上ＥＬ層１５の厚さの半分以下となるように形成したが、以下の三通りの何れか方法によって中心線平均粗さＲａが０．５ｎｍ以上ＥＬ層１５の厚さの半分以下となるアノード１３を形成しても良い。
【００６９】
〔別の方法（１）〕
トランジスタ２１，２１，…をパターニングする時に、酸化インジウム、酸化亜鉛若しくは酸化スズ又はこれらのうちの少なくとも一つを含む混合物（例えば、錫ドープ酸化インジウム（ＩＴＯ）、亜鉛ドープ酸化インジウム）からなる透明導電層をゲート絶縁膜２３一面に成膜するが、中心線平均粗さＲａが０．５ｎｍ以上ＥＬ層１５の厚さの半分以下であれば、その成膜方法ＥＢ蒸着法に限らず、イオンプレーティング法、スパッタ法、その他のＰＶＤ法、ＣＶＤ法であっても良い。透明導電層の成膜後に透明導電層にマスクを施し、マスクに従って透明導電層を形状加工し、マスクを除去すると、アノード１３，１３，…がマトリクス状にパターニングされる（図３（ａ））。
【００７０】
アノード１３，１３，…及びトランジスタ２１，２１，…の形成後、上述の場合と同様にアノード１３，１３，…を囲繞するように網目状の保護絶縁膜１８を形成する（図３（ｂ））。
【００７１】
次いで、アノード１３，１３，…の露出した部分に対してソフトエッチングを施すことによって、配向性によるエッチングレートの差によりアノード１３，１３，…の表面は中心線平均粗さＲａが０．５ｎｍ以上ＥＬ層１５の厚さの半分以下となるように形成される。
そして、以上に説明した場合と同じようにパターン膜１４、ＥＬ層１５，１５，…、カソード１６を形成する。
この方法では、アノード１３，１３，…の形成方法が、ＥＢ蒸着法に限定されないため、アノード１３，１３，…の形成方法の自由度が増す。
【００７２】
〔別の方法（２）〕
トランジスタ２１，２１，…をパターニングする時に、ＰＶＤ法又はＣＶＤ法によって、酸化インジウム、酸化亜鉛若しくは酸化スズ又はこれらのうちの少なくとも一つを含む混合物（例えば、錫ドープ酸化インジウム（ＩＴＯ）、亜鉛ドープ酸化インジウム）からなる透明導電層をゲート絶縁膜２３一面に成膜する。透明導電層の成膜後に透明導電層にマスクを施し、マスクに従って透明導電層を形状加工し、マスクを除去すると、アノード１３，１３，…がマトリクス状にパターニングされる（図３（ａ））。アノード１３，１３，…及びトランジスタ２１，２１，…の形成後、上述の場合と同様にアノード１３，１３，…を囲繞するように網目状の保護絶縁膜１８を形成する（図３（ｂ））。
【００７３】
次いで、アノード１３，１３，…の露出した部分に向けてケイ砂等のブラスト材を吹き付けることによって（ブラスト法）、アノード１３，１３，…の表面は中心線平均粗さＲａが０．５ｎｍ以上ＥＬ層１５の厚さの半分以下となるように形成される。ブラスト材としてケイ砂を用いるブラスト法を特にサンドブラスト法という。次いで、アノード１３，１３，…の表面に付着したブラスト材を水洗等により洗い流す。
そして、以上に説明した場合と同じようにパターン膜１４、ＥＬ層１５，１５，…、カソード１６を形成する。
以上のようなブラスト法は薬品を用いず行うことができるため、薬品の廃棄・処理するという問題がない。
【００７４】
〔別の方法（３）〕
トランジスタ２１，２１，…をパターニングする時に、ＰＶＤ法又はＣＶＤ法によって、酸化インジウム、酸化亜鉛若しくは酸化スズ又はこれらのうちの少なくとも一つを含む混合物（例えば、錫ドープ酸化インジウム（ＩＴＯ）、亜鉛ドープ酸化インジウム）からなる透明導電層をゲート絶縁膜２３一面に成膜する。透明導電層の成膜後に透明導電層にマスクを施し、マスクに従って透明導電層を形状加工し、マスクを除去すると、アノード１３，１３，…がマトリクス状にパターニングされる（図３（ａ））。アノード１３，１３，…及びトランジスタ２１，２１，…の形成後、上述の場合と同様にアノード１３，１３，…を囲繞するように網目状の保護絶縁膜１８を形成する（図３（ｂ））。
【００７５】
次いで、アノード１３，１３，…の露出した部分に、Ａｌ₂Ｏ₃、ＴｉＯ₂、ＳｉＯ₂等の無機物を１０〜２０Å（オングストローム）の膜厚でスパッタ法により成膜する。無機物層の膜厚が１０〜２０Åと非常に極薄であるため、その膜は所々で欠陥があって非連続となっている。そして、無機物層をマスクとしてウェットエッチング又はドライエッチングをアノード１３，１３，…に施すことにより、アノード１３，１３，…の表面は中心線平均粗さＲａが０．５ｎｍ以上ＥＬ層１５の厚さの半分以下となるように形成される。エッチング後に無機物層を除去しなくても良い。
そして、以上に説明した場合と同じようにパターン膜１４、ＥＬ層１５，１５，…、カソード１６を形成する。
この方法では、アノード１３，１３，…上に無機物層のマスクを施しているため、エッチング方法、エッチング条件の制限が緩くなり、アノード１３，１３，…に対してエッチングすることができる環境が厳しく制限されない。
【００７６】
なお、本発明は上記実施の形態に限定されることなく、本発明の趣旨を逸脱しない範囲において、種々の改良並びに設計の変更を行っても良い。
例えば、上記実施形態の有機ＥＬ表示パネル１は自発光式であるため、ページプリンタといった画像形成装置の線走査機構に用いることができる。
また、上述の説明では、カソード１６が全ての有機有機ＥＬ素子１１，１１，…について共通しているが、カソードとアノードの配置を代えて有機有機ＥＬ素子１１各画素ごとにカソードを形成しても良い。
また、板状の透明基板１２の代わりにシート状の透明なフィルム基板であっても良い。
【００７７】
また、上述の説明では液滴吐出法によって複数のＥＬ層１５，１５，…をパターニングしていた。しかしながら、パターン膜１４では親液性領域１４ａ，１４ａ，…がマトリクス状にパターニングされているため、有機化合物含有液をパターン膜１４に塗布して透明基板１２を回転させること（スピンコート法）によって、複数のＥＬ層１５，１５，…をマトリクス状にパターニングすることができる。また、パターン膜１４の親液性と撥液性のパターニングを利用して、ディップコート法又はダイコート法によって複数のＥＬ層１５，１５，…をマトリクス状にパターニングしても良い。更には、平版印刷法、凹版印刷法、凸版印刷法を用いて複数のＥＬ層１５，１５，…をマトリクス状にパターニングしても良い。
【００７８】
また、上述の説明ではディップコート法によって濡れ性可変層１４’を成膜したが、スピンコート法、刷毛塗り法又は蒸着法によって濡れ性可変層１４’を成膜しても良い。
【００７９】
また、上述の説明では濡れ性可変層１４’に光触媒が含まれていないが、光触媒を含有したシラザン系溶液を塗布することによって濡れ性可変層１４’に光触媒を含有させても良い。この場合には、フォトマスク基板４０に光触媒膜４３を設けなくても良い。
【００８０】
また、フッ素を含む官能基を有するシラン化合物として、シラザン化合物を挙げたが、シランカップリング剤（加水分解重合可能なフルオロアルキル基含有珪素化合物）といった他のシラン化合物やその他の撥液性を示す官能基でもよく、置換される官能基は水酸基以外の親液性の官能基であっても良い。
【００８１】
また、保護絶縁膜１８をパターニングした後であって濡れ性可変層１４’を成膜する前に、図５に示すように保護絶縁膜１８に重なるようにして網目状の仕切り壁２０をパターニングしても良い。仕切り壁２０の幅は、透明基板１２に近づくにつれて大きく、保護絶縁膜１８の幅より狭い。仕切り壁２０は、絶縁性を有しており、ポリイミド樹脂、ノボラック樹脂、アクリル樹脂等といった樹脂で形成されている。
【００８２】
【実施例】
以下に、実施例を挙げることにより、本発明をさらに具体的に説明する。
第一の実施例では、上記実施形態で説明したようにＩＴＯからなるアノード１３，１３，…をＥＢ蒸着法で成膜した。アノード１３，１３，…の中心線平均粗さＲａを、原子間力顕微鏡（ＡＦＭ）で上記（ｂ）式に沿ってカットオフ値１２．５μとして測定したところ、１０．５ｎｍであった。この場合に、フォトマスク基板４０を用いて露光する前に、濡れ性可変層１４’のうちアノード１３に重なった部分（撥液性を示す）に有機化合物含有液を滴下し、有機化合物含有液の接触角を測定した。更に、フォトマスク基板４０を用いて露光した後にアノード１３に重なった親液性領域１４ａに有機化合物を滴下し、有機化合物含有液の接触角を測定した。有機化合物含有液として、ＰＥＤＯＴ及びＰＳＳを水系溶媒に分散させた分散液にエタノールを添加したもの（有機化合物含有液Ｎｏ．１）と、有機化合物含有液Ｎｏ．１よりもエタノールの添加量を二倍にした（有機化合物含有液Ｎｏ．２）ものを用いた。有機化合物含有液Ｎｏ．１の重量比は、水：エタノール：ＰＥＤＯＴ及びＰＳＳ＝９４．２５ｗｔ％：５ｗｔ％：０．７５ｗｔ％であり、有機化合物含有液Ｎｏ．２の重量比は、水：エタノール：ＰＥＤＯＴ及びＰＳＳ＝８９．２５ｗｔ％：１０ｗｔ％：０．７５ｗｔ％である。有機化合物含有液にエタノールを添加したのは、エタノールを添加しないと分散液の粘性が高くてインクジェットヘッドを用いた液滴吐出法で分散液を連続して塗布することができないためである。有機化合物含有液Ｎｏ．１のエタノール添加量は、液滴吐出法で実用することのできる下限であり、有機化合物含有液Ｎｏ．１より少ない添加量では液滴吐出法で連続して液滴を吐出することができない。
【００８３】
第二の実施例では、アノード１３，１３，…をＨＤＡＰ−ＩＰ法（イオンプレーティング法）で成膜し、アノード１３，１３，…の中心線平均粗さＲａを０．８ｎｍとした。第三の実施例では、アノード１３，１３，…をスパッタ法で成膜し、アノード１３，１３，…の中心線平均粗さＲａを４．１ｎｍとした。そして、実施例と同様にして、露光前の濡れ性可変層１４’のうちアノード１３に重なった部分（撥液性を示す）に有機化合物含有液を滴下し、有機化合物含有液の接触角を測定するとともに、露光後にアノード１３に重なった親液性領域１４ａに有機化合物を滴下し、有機化合物含有液の接触角を測定した。
測定結果を表１に示す。
【００８４】
【表１】

【００８５】
表１からわかるように、露光後の接触角を比較すると、ＨＤＡＰ−ＩＰ法の場合、スパッタ法の場合、ＥＢ蒸着法の場合の順に接触角が小さくなり、ＥＢ蒸着法を用いてアノード１３を成膜すると有機化合物含有液が親液性領域１４ａで最も濡れやすいことがわかる。
また、ＥＢ蒸着法の場合は、他の方法の場合に比較して、露光前では接触角が最も大きく、有機化合物含有液を最もはじきやすいことがわかる。更に、ＥＢ蒸着法の場合、他の方法の場合に比較して、露光前から露光後の間で接触角の変化率が最も大きいことがわかる。
いずれの場合も、親液性領域１４ａの接触角が２５°以下となり有機化合物含有液の成膜に有効であることが確認された。特にＥＢ蒸着法では特に中心線平均粗さＲａが１０ｎｍ以上になり、親液性領域１４ａの接触角が１５°以下となり、著しく接触角の改善がみられた。また撥液性領域１４ｂの接触角も１１０°を越えているため、精度の高いＥＬ層１５の成膜を行うことができる。
【００８６】
【発明の効果】
本発明によれば、第一電極の表面粗さＲａが大きいため、第一電極上に形成された親液性膜、第一電極上に形成されるとともに活性光線に照射された部分が、より有機化合物含有液に対してなじみやすく、有機化合物含有液がより良く濡れる。そのため、有機化合物含有液が親液性膜又は露光された部分全体に滲み、ＥＬ層の成膜不良を抑えることができる。
【図面の簡単な説明】
【図１】本発明を適用した有機ＥＬ表示パネルを示した平面図である。
【図２】図１に示された有機ＥＬ表示パネルの断面図である。
【図３】図１に示された有機ＥＬ表示パネルの製造工程を示した図面である。
【図４】図３の続きの製造工程を示した図面である。
【図５】図１に示された有機ＥＬ表示パネルとは別の有機ＥＬ表示パネルを示した断面図である。
【符号の説明】
１０ 有機ＥＬ表示パネル（有機ＥＬパネル）
１１ 有機ＥＬ素子
１２ 透明基板（基板）
１３ アノード（第一電極）
１４’ 濡れ性可変層
１４ パターン膜
１４ａ 親液性領域（親液性膜）
１４ｂ 撥液性領域
１５ ＥＬ層
１６ カソード（第二電極）[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing an organic EL (Electro Luminescence) element and a method for manufacturing an organic EL panel in which a plurality of organic EL elements are arranged on a substrate.
[0002]
[Prior art]
The organic EL element has a laminated structure in which an anode, an EL layer, and a cathode are laminated in this order. When a positive bias voltage is applied between the anode and the cathode, light is emitted from the EL layer. An organic EL display panel that displays images by arranging such organic EL elements as pixels in a matrix on a substrate and emitting each organic EL element with a predetermined gradation luminance is realized.
[0003]
Patent Document 1 describes a method for manufacturing an organic EL element. In the manufacturing method described in this document, after forming a photocatalyst containing layer on the anode, the photocatalyst containing layer is exposed in a pattern to form a pattern due to a difference in wettability, and the photocatalyst containing layer contains an organic compound. An EL layer is formed by wet application of the liquid, and a cathode is formed on the EL layer. In this method, wettability is improved in the exposed portion of the photocatalyst-containing layer, and wettability is low in the unexposed portion, so that an EL layer is formed in the exposed portion.
[0004]
[Patent Document 1]
JP 2001-237069 A
[0005]
[Problems to be solved by the invention]
However, even if the photocatalyst-containing layer is exposed to improve the wettability of the exposed portion, it cannot be said that the wettability is still sufficiently high. Therefore, the organic compound-containing liquid may not bleed over the entire exposed portion, and the EL layer formed by drying the organic compound-containing liquid becomes thicker at the center of the exposed portion and thinner at the periphery. Deposition failure occurs.
Therefore, an object of the present invention is to make the organic compound-containing liquid easier to wet and to reliably form an EL layer.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the invention according to claim 1 is, for example, as shown in FIGS.
An organic layer in which a first electrode (for example, anode 13), at least one EL layer (for example, EL layer 15), and a second electrode (for example, cathode 16) are stacked in this order on a substrate (for example, transparent substrate 17). In the manufacturing method of the organic EL element for manufacturing the EL element (for example, the organic EL element 11),
A first electrode forming step of forming the first electrode on the substrate having a surface roughness Ra of 0.5 nm or more and half or less of the thickness of the EL layer;
Forming a lyophilic film (for example, the lyophilic region 14a of the pattern film 14) on the first electrode, which is compatible with the organic compound-containing liquid containing the material of the EL layer, and the lyophilic film Forming the EL layer by applying the organic compound-containing liquid thereon;
It is characterized by including.
[0007]
According to a second aspect of the present invention, in the method for manufacturing an organic EL element according to the first aspect, in the first electrode forming step, the surface roughness Ra is 0.5 nm or more by an EB vapor deposition method. A step of forming the first electrode that is less than half the length.
[0008]
According to a third aspect of the present invention, in the method of manufacturing an organic EL element according to the first aspect, the first electrode forming step includes the step of forming the first electrode, and then the softening of the first electrode. Forming a surface roughness Ra of the first electrode to 0.5 nm or more and half or less of the thickness of the EL layer by etching.
[0009]
According to a fourth aspect of the present invention, in the method of manufacturing an organic EL element according to the first aspect, the first electrode forming step includes the step of forming the first electrode, and then the step of forming the first electrode. Forming a surface roughness Ra of the first electrode to 0.5 nm or more and half or less of the thickness of the EL layer by performing a blasting process.
[0010]
According to a fifth aspect of the present invention, in the method of manufacturing an organic EL element according to the first aspect, the first electrode forming step includes a step of forming the first electrode, and then on the first electrode. The method includes a step of forming an inorganic layer having a thickness of 10 to 20 mm and a step of etching the first electrode using the inorganic layer as a mask.
[0011]
The invention according to claim 6 is, for example, as shown in FIGS.
Organic EL panel for manufacturing an organic EL panel (for example, organic EL display panel 10) in which a plurality of organic EL elements (for example, organic EL elements 11, 11,...) Are arranged on a substrate (for example, transparent substrate 17). In the manufacturing method of
First electrode formation in which a plurality of first electrodes (for example, anodes 13, 13,...) Having a surface roughness Ra of 0.5 nm or more and less than half of the thickness of the EL layer are formed on the substrate at intervals. Process,
Forming a wettability variable layer (for example, wettability variable layer 14 ′) that improves wettability to the organic compound-containing liquid by irradiation with actinic rays so as to cover the plurality of first electrodes together;
Irradiating a region of the wettability variable layer overlapping each first electrode with an actinic ray for modifying the wettability variable layer;
By applying an organic compound-containing liquid to a region of the wettability variable layer that overlaps each of the first electrodes, on each of the first electrodes, the thickness is at least twice the surface roughness Ra. Forming one or more EL layers;
It is characterized by including.
[0012]
A seventh aspect of the present invention is the method of manufacturing an organic EL panel according to the sixth aspect, wherein in the first electrode forming step, the surface roughness Ra is 0.5 nm or more by an EB vapor deposition method. Forming the plurality of first electrodes less than half of the length.
[0013]
The invention according to claim 8 is the method of manufacturing an organic EL panel according to claim 6, wherein the first electrode forming step includes a step of forming the plurality of first electrodes, and then the plurality of first electrodes. Forming a surface roughness Ra of the plurality of first electrodes to 0.5 nm or more and half or less of the thickness of the EL layer by performing soft etching on one electrode.
[0014]
A ninth aspect of the present invention is the method of manufacturing an organic EL panel according to the sixth aspect, wherein the first electrode forming step includes a step of forming the plurality of first electrodes, and then the plurality of first electrodes. Forming a surface roughness Ra of the plurality of first electrodes to be not less than 0.5 nm and not more than half of the thickness of the EL layer by performing a blasting method on one electrode.
[0015]
According to a tenth aspect of the present invention, in the method for manufacturing an organic EL panel according to the sixth aspect, the first electrode forming step includes a step of forming the plurality of first electrodes, and then the plurality of first electrodes. A step of forming an inorganic layer having a thickness of 10 to 20 mm on one electrode and etching the plurality of first electrodes using the inorganic layer as a mask reduces the surface roughness Ra of the plurality of first electrodes to 0. And a step of forming the EL layer to be not more than half the thickness of the EL layer.
[0016]
In the invention according to claims 1 to 10, since the surface roughness Ra of the first electrode is 0.5 nm or more and half or less of the thickness of the EL layer, the first electrode is formed on the first electrode and irradiated with actinic rays. The lyophilic film formed on the formed part or the first electrode has a contact angle of 25 ° or less, and is more easily adapted to the organic compound-containing liquid, and the organic compound-containing liquid is better wetted. For this reason, the organic compound-containing liquid oozes over the lyophilic film or the entire exposed portion, and the formation failure of the EL layer can be suppressed.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples. Further, in the following description, “in plan view” means “seen in a direction perpendicular to the transparent substrate 12 (described later)”.
[0023]
FIG. 1 is a plan view of an organic EL display panel 10 manufactured by a manufacturing method to which the present invention is applied. FIG. 2 is a cross-sectional view taken along the cutting line S1-S2 shown in FIG. It is.
[0024]
The organic EL display panel 10 has pixels arranged in a matrix in plan view, and performs matrix display by an active matrix driving method. In the organic EL display panel 10, one organic EL element 11 and one pixel circuit are provided for each pixel. The pixel circuit receives a signal from a peripheral driver (not shown) via the signal line 51 and the scanning line 52, and turns on / off a current flowing through the organic EL element 11 according to the input signal, and emits light from the organic EL element 11. By maintaining the current value during the period, the emission luminance of the organic EL element 11 is provided to be constant. Each pixel circuit is composed of at least one transistor, and a capacitor may be added as appropriate. In FIG. 1, for example, the pixel circuit is composed of two transistors 21 and 21. .
[0025]
The organic EL display panel 10 has a flat transparent substrate 12, and a plurality of scanning lines 52, 52,... Extending in the horizontal direction are formed on the surface 12 a of the transparent substrate 12. The scanning lines 52, 52,... Are arranged in parallel with each other at substantially equal intervals in plan view. The scanning lines 52, 52,... Have conductivity and are covered with a gate insulating film 23 formed on the entire surface 12 a of the transparent substrate 12. A plurality of signal lines 51, 51,... Extending in the vertical direction are formed on the gate insulating film 23, and the signal lines 51, 51,. They are orthogonal to each other. The signal lines 51, 51,... Are also arranged in parallel with each other at substantially equal intervals in plan view.
[0026]
A plurality of transistors 21, 21,... Are formed on the surface 12 a of the transparent substrate 12. Each transistor 21 includes a gate electrode 22, a gate insulating film 23, a semiconductor film 24, impurity semiconductor films 25 and 26, a drain electrode 27, and a source electrode 28, and is a MOS field effect thin film transistor in which these are stacked. is there. The gate insulating film 23 is formed on the entire surface 12a of the transparent substrate 12, and is a layer common to all the transistors 21, 21,.
[0027]
.. Are covered with a protective insulating film 18. In plan view, the protective insulating film 18 is formed in a mesh shape so as to overlap the signal lines 51, 51,... And the scanning lines 52, 52,. When the protective insulating film 18 is formed in a mesh shape in a plan view, a plurality of surrounding regions 19, 19,... Surrounded by the protective insulating film 18 are arranged in a matrix on the transparent substrate 12. It is formed. The protective insulating film 18 is made of silicon oxide (SiO ₂ ) And silicon nitride (SiN).
[0028]
Next, the organic EL element 11 will be described. The organic EL element 11 has a laminated structure in which an anode 13 as a first electrode, an EL layer 15 made of an organic compound, and a cathode 16 as a second electrode are laminated in this order from the transparent substrate 12 side. The anode 13 is transmissive to visible light and conductive, and has a relatively high work function. The anode 13 is formed of, for example, indium oxide, zinc oxide, tin oxide, or a mixture containing at least one of them (for example, tin-doped indium oxide (ITO), zinc-doped indium oxide).
[0029]
In plan view, the anodes 13, 13,... Are disposed in regions surrounded by the signal lines 51, 51,... And the scanning lines 52, 52,. They are arranged on the gate insulating film 23 so as to form a matrix.
[0030]
In plan view, the anodes 13, 13,... Respectively correspond to the surrounding areas 19, 19,. In plan view, the area of the surrounding region 19 is smaller than the area of the anode 13, and the surrounding region 19 is disposed in the anode 13, and the outer peripheral portion of the anode 13 overlaps the protective insulating film 18. In this example, the anode 13 is connected to the source electrode 28 of the transistor 21, but the anode 13 may be connected to another transistor or capacitor depending on the circuit configuration of the pixel circuit.
[0031]
On the anodes 13, 13,..., The pattern film 14 is formed in common for all the organic EL elements 11, 11,..., And each of the anodes 13, 13,. The center line average roughness Ra is 0.5 nm or more and half or less of the thickness of the EL layer 15 (that is, if the thickness of the EL layer 15 is t [nm], 0.5 ≦ center line average roughness Ra ≦ t / 2). When the center line average roughness Ra exceeds half of the total thickness of the EL layer 15, the thickness of the EL layer 15 at the convex portion of the anode 13 becomes extremely thinner than the thickness of the EL layer 15 at the concave portion of the anode 13. As a result, the electric field concentrates and the anode 13 and the cathode 16 may be short-circuited. The pattern film 14 is formed on the entire surface of the transparent substrate 12, and covers the protective insulating film 18 together with the anodes 13, 13,. The pattern film 14 conforms to the organic compound-containing liquid in a region overlapping with the anodes 13, 13,..., And wets the organic compound-containing liquid at a contact angle of 40 ° or less (hereinafter “lyophilic”). ... and the lyophilic regions 14a, 14a,..., And the region overlapping the protective insulating film 18, the organic compound-containing solution is wetted at a contact angle of 50 ° or less (hereinafter referred to as the organic compound-containing solution). , And “showing liquid repellency”). That is, in the pattern film 14, the liquid repellent region 14b is formed in a mesh shape in plan view, and the lyophilic regions 14a, 14a,... Are arranged in a matrix so as to be surrounded by the liquid repellent region 14b. Is formed. In plan view, the area of the lyophilic region 14a is larger than the area of the surrounding region 19, and the entire surrounding region 19 is included in the lyophilic region 14a.
[0032]
The lyophilic region 14a of the pattern film 14 is very thin, and its thickness is greater than 0.0 nm and less than 1 nm. The organic compound-containing liquid is a liquid containing an organic compound constituting the EL layer 15 or a precursor thereof, and even if the organic compound constituting the EL layer 15 or a precursor thereof is dissolved in a solvent as a solute. Alternatively, a dispersion liquid in which the organic compound constituting the EL layer 15 or a precursor thereof is dispersed in a liquid may be used. At this time, the organic compound-containing liquid may be oleophilic like an organic material or hydrophilic like water.
[0033]
In a plan view, the EL layers 15, 15,... Are arranged in a matrix and are formed on the lyophilic regions 14a, 14a,.
[0034]
Each EL layer 15 is a layer formed of a light emitting material that is an organic compound, and generates light by emitting excitons by recombining holes injected from the anode 13 and electrons injected from the cathode 16. It is a layer to do. Further, each EL layer 15 may be appropriately mixed with an electron transporting substance, may be appropriately mixed with a hole transporting substance, or may be mixed with an electron transporting substance and a hole transporting substance. Substances may be mixed as appropriate.
[0035]
Each EL layer 15 has a three-layer structure that becomes a hole transport layer, a light-emitting layer in a narrow sense, and an electron transport layer in order from the anode 13, or a two-layer structure that becomes a hole transport layer and a light-emitting layer in a narrow sense in order from the anode 13. Or a single layer structure composed of a light-emitting layer in a narrow sense, or a laminated structure in which an electron or hole injection layer is interposed between appropriate layers in these layer structures. The EL layer 15 is formed by applying an organic compound-containing liquid (that is, a wet application method). The thickness of the EL layer 15 is at least twice the center line average roughness Ra of the anode 13.
[0036]
The cathode 16 is continuously formed on the entire surface of the transparent substrate 12 so as to cover all the EL layers 15, 15. The cathode 16 includes at least a material having a low work function, and is specifically formed of a simple substance made of magnesium, calcium, lithium, barium, or a rare earth, or an alloy containing at least one of these simple substances. Further, the cathode 16 may have a laminated structure, for example, a laminated structure in which a film formed of a low work function material as described above is coated with a high work function and low resistivity material such as aluminum or chromium. But it ’s okay. The cathode 16 desirably has a light blocking property with respect to visible light, and further desirably has a high reflectivity with respect to visible light emitted from the EL layer 15. That is, the cathode 16 acts as a mirror surface that reflects visible light, so that the light use efficiency can be improved.
[0037]
As described above, the pattern film 14 and the cathode 16 are layers common to all the organic EL elements 11, 11,..., And the anode 13 and the EL layer 15 are formed independently for each organic EL element 11. ing.
[0038]
Next, a method for manufacturing the organic EL display panel 10 will be described with reference to FIGS.
First, the signal lines 51, 51,... And the scanning lines 52 are appropriately formed by performing a thin film shape processing process such as a film forming process such as a sputtering method, a PVD method and a CVD method, a mask process such as a photolithography method, and an etching method. , 52,... Are patterned and the anode 13 and the transistors 21, 21 are patterned on the surface 12a of the transparent substrate 12 for each pixel (FIG. 3A). Here, when the anode 13 and the transistor 21 are formed by patterning, they are masked with a resist so that the source electrode 28 of the transistor 21 and the anode 13 are connected.
[0039]
In forming the anodes 13, 13,..., Indium oxide, zinc oxide, tin oxide, or a mixture containing at least one of them (for example, tin-doped indium oxide (ITO), zinc-doped indium oxide). A transparent conductive layer is formed on the entire surface of the gate insulating film 23. In particular, the transparent conductive layer is formed by EB vapor deposition (electron beam vapor deposition). When the transparent conductive layer is formed by the EB vapor deposition method, the center line average roughness Ra of the surface of the transparent conductive layer becomes 0.5 nm or more and half or less of the thickness of the EL layer 15. After forming the transparent conductive layer, the transparent conductive layer is masked, and the transparent conductive layer is shaped according to the mask by etching or the like. When the mask is removed, the center line average roughness Ra is 0.5 nm or more. Are patterned in a matrix.
The center line average roughness Ra of the anode 13 indicates the degree of average unevenness on the surface of the anode 13, and a linear axis in a predetermined direction in the substantially plane direction of the anode 13 is an x-axis, and the approximate surface of the anode 13. The roughness curve f (x) that is the unevenness of the surface of the anode 13 is expressed by the following equation (a), where y is the axis in the normal direction.
y = f (x) (a)
Can be expressed as
Here, a roughness curve f (x) from position 0 to position s (reference length s in the x-axis direction) in the x-axis direction of the anode 13 is extracted, and the roughness curve is derived from the curve drawn by the surface of the anode 13. This is the average line of the roughness curve f (x) that minimizes the square sum of the deviations up to f (x). Of the area that is parallel to the average line of the roughness curve f (x) and is surrounded by the parallel straight line and the roughness curve f (x), the areas of the convex side and the concave side are equal. It becomes the center line of the roughness curve f (x).
The center line average roughness Ra from position 0 to position s along the direction of the center line of the roughness curve f (x) from the roughness curve f (x) is expressed by the following formula (b).
[Expression 1]

[0040]
After the anodes 13, 13,... And the transistors 21, 21,... Are formed, a film forming process such as a PVD method and a CVD method, a mask process such as a photolithography method, and a thin film shape processing process such as an etching method are performed. A network-like protective insulating film 18 is formed so as to surround 13, 13,. By forming the protective insulating film 18, the surrounding regions 19, 19,... Surrounded by the protective insulating film 18 are formed, and the anode 13 is exposed in each surrounding region 19 (FIG. 3B).
[0041]
Next, the surface 12a side of the transparent substrate 12, that is, the surfaces of the anodes 13, 13,... And the protective insulating film 18 is cleaned. The cleaning may be oxygen plasma cleaning under reduced pressure below atmospheric pressure, or ultraviolet / ozone cleaning. Thereafter, the surfaces of the anodes 13,... And the protective insulating film 18, the back surface of the transparent substrate 12, and the others are washed with pure water. Next, an inert gas such as nitrogen gas is sprayed on the transparent substrate 12 to dry the transparent substrate 12.
[0042]
Next, a film composed of a silane compound having a fluorine-containing functional group, particularly a silazane compound having a fluorine-containing functional group among silane compounds, is coated on the surface 12 a side of the transparent substrate 12. Specifically, the surface of the transparent substrate 12 is obtained by immersing the transparent substrate 12 in a solution containing a silazane compound having a functional group containing fluorine (hereinafter referred to as a silazane-based solution) and then pulling up the transparent substrate 12. A silazane solution is applied to the entire surface of the 12a side (dip coating method).
[0043]
Here, the “silazane compound having a functional group containing fluorine” is a compound having a Si—N—Si bond, and a functional group containing fluorine bonded to N or / and Si. The oligomer or polymer represented by Formula (1) is mentioned.
RfSi (NH) _3/2 ... (1)
In the general formula (1), Rf is a functional group containing fluorine.
The “functional group containing fluorine” includes a fluoroalkyl group, and examples thereof include functional groups represented by the following general formulas (2) to (19).
-(CH ₂ ) _a (CF ₂ ) _b CF _Three ... (2)
-(CH ₂ ) _a (CF ₂ ) _b CF (CF _Three ) ₂ ... (3)
-(CH ₂ ) _a (CF ₂ ) _b C (CF _Three ) _Three ... (4)
-(CF ₂ ) _a CF _Three ... (5)
-(CF ₂ ) _a CF (CF _Three ) ₂ ... (6)
-(CF ₂ ) _a C (CF _Three ) _Three ... (7)
-(CF ₂ ) _a (C (CF _Three ) ₂ ) _b CF _Three (8)
-(CF ₂ ) _a (C (CF _Three ) ₂ ) _b CF (CF _Three ) ₂ ... (9)
-(CF ₂ ) _a (C (CF _Three ) ₂ ) _b C (CF _Three ) _Three (10)
-(CF ₂ ) _a (C (CF _Three ) ₂ ) _b (CF ₂ ) _c CF _Three ... (11)
-(CF ₂ ) _a (C (CF _Three ) ₂ ) _b (CF ₂ ) _c CF (CF _Three ) ₂ (12)
-(CF ₂ ) _a (C (CF _Three ) ₂ ) _b (CF ₂ ) _c C (CF _Three ) _Three ... (13)
-(C (CF _Three ) ₂ ) _a CF _Three ... (14)
-(C (CF _Three ) ₂ ) _a CF (CF _Three ) ₂ ... (15)
-(C (CF _Three ) ₂ ) _a C (CF _Three ) _Three ... (16)
-(C (CF _Three ) ₂ ) _a (CF ₂ ) _b CF _Three ... (17)
-(C (CF _Three ) ₂ ) _a (CF ₂ ) _b CF (CF _Three ) ₂ ... (18)
-(C (CF _Three ) ₂ ) _a (CF ₂ ) _b C (CF _Three ) _Three ... (19)
In general formulas (2) to (19), a, b, and c are all integers.
[0044]
Examples of the solvent for the silazane solution include a fluorine solvent.
[0045]
Here, as the silazane compound, a silazane oligomer (KP-801M: manufactured by Shin-Etsu Chemical Co., Ltd.) represented by the following general formula (20) and chemical structural formula (21) is used. In the above dip coating step, the transparent substrate 12 is immersed for about 1 minute in a silazane-based solution (concentration: 3 wt%) in which the silazane oligomer is dissolved in an m-xylene hexafluoride solvent.
C ₈ F ₁₇ C ₂ H _Four Si (NH) _3/2 ... (20)
[Chemical 1]

[0046]
Next, an inert gas such as nitrogen gas is blown onto the transparent substrate 12 to evaporate the solvent of the silazane solution, whereby the silazane compound is deposited on the surfaces of the anodes 13, 13,... And the protective insulating film 18. .
[0047]
Next, when the transparent substrate 12 is left for 10 to 30 minutes, the silazane compound is hydrolyzed and polymerized by moisture in the atmosphere and chemically bonded to the protective insulating film 18. As a result, as shown in FIG. 3C, the wettability variable layer 14 ′ made of a polymer to which a functional group containing fluorine is bonded covers the anodes 13, 13,... And the protective insulating film 18 as a whole. A film is formed. The polymer contained in the wettability variable layer 14 ′ is represented by the following general formula (22).
[Chemical formula 2]

[0048]
In the general formula (22), Rf is a functional group containing fluorine as described above and exhibiting liquid repellency, X is an atom or atomic group of the anode 13 bonded to the silazane compound, and the protective insulating film 18. Atom or atomic group, a part of the atom or atomic group of the silazane compound bonded to the surface of the anode 13 or the protective insulating film 18, or an atom or atom constituting a group substituted by the NH group in the chemical structural formula (21) N is an integer of 100 or more. When the silazane compound is a silazane oligomer represented by the general formula (20), Rf is C ₈ F ₁₇ C ₂ H _Four And X becomes O. Since the silazane compound has high activity and is easily adsorbed to the anodes 13, 13,... And the protective insulating film 18, the wettability variable layer 14 ′ is chemically adsorbed on the surfaces of the anodes 13, 13,. Is formed. Therefore, in the wettability variable layer 14 ′, the Rf—Si—X— group or the Rf—Si— group, which is the main chain in the monomolecular unit of the silazane compound, is formed on the surfaces of the anodes 13, 13,. , Which are arranged in a substantially vertical direction with respect to each other and polymerize oxygen in an ether-bonded state by hydrolysis in the direction along the surfaces of the anodes 13, 13,... And the protective insulating film 18. Has been. That is, the silazane compound is polymerized in the surface direction of the surfaces of the anodes 13, 13,... And the protective insulating film 18, and in the monomolecular unit formed on the surfaces of the anodes 13, 13,. The main chain Rf-Si-X- group or Rf-Si- group in the single molecular unit is hardly stacked above the main chain Rf-Si-X- group or Rf-Si- group. For this reason, the thickness of the wettability variable layer 14 ′ is substantially equal to the Rf—Si—X— group or Rf—Si— which is the main chain (here, corresponds to a side chain as a polymer) in a monomolecular unit. Equal to the base length. Further, the wettability variable layer 14 ′ is polymerized so that the functional group Rf containing fluorine in the main chain in each monomolecular unit is arranged on the surface side of the wettability variable layer 14 ′. The liquid repellency of the functional group Rf exhibits liquid repellency with respect to the organic compound-containing liquid.
[0049]
Next, after leaving the transparent substrate 12 to stand, the surface 12a side of the transparent substrate 12 is rinsed with an m-xylene hexafloid liquid, so that the unreacted silazane compound deposited on the surfaces of the anodes 13, 13,. Rinse away. At this time, in the anodes 13, 13,..., The center line average roughness Ra is 0.5 nm or more and less than half of the thickness of the EL layer 15, and the difference in unevenness is large, and the surface area of the anode 13 per pixel is sufficiently large. The actual area where the wettability variable layer 14 ′ on the surface of the anode 13 is applied is also large.
[0050]
Next, as shown in FIG. 3 (d), the wettability is variable by the catalytic action generated by irradiating the photocatalyst film 43 of the photomask substrate 40, which will be described later, with the photomask substrate 40 facing the transparent substrate 12 and irradiating actinic rays. The layer 14 ′ becomes the pattern film 14. Active light includes visible light, ultraviolet light, infrared light, and the like, and excites a photocatalytic film 43 described later.
[0051]
Here, the photomask substrate 40 will be described. The photomask substrate 40 has a transparent substrate 41 that transmits actinic rays, and a plurality of openings arranged in a matrix so as to correspond to the surrounding regions 19, 19,... On one surface 41 a of the transparent substrate 41. A mask 42 having a portion is formed in a mesh shape, and a photocatalytic film 43 having a thickness of about 0.2 μm is formed on one surface 41 a so as to cover the entire mask 42. That is, the mask 42 is formed in a pattern corresponding to the protective insulating film 18. The opening area of the opening surrounded by the mask 42 is slightly larger than the area of the surrounding region 19.
[0052]
The mask 42 reflects or absorbs actinic rays and does not transmit actinic rays. The photocatalytic film 43 is made of titanium oxide (TiO ₂ ), Zinc oxide (ZnO), tin oxide (SnO) ₂ ), Strontium titanate (SrTiO) _Three ), Tungsten oxide (WO _Three ), Bismuth oxide (Bi ₂ O _Three ) And iron oxide (Fe ₂ O _Three 1) or two or more kinds of substances selected from among the above. Here, titanium oxide is used as the photocatalytic film 43. Titanium oxide includes anatase type and rutile type, and both can be used in the present invention, but anatase type titanium oxide is more preferable because the excitation wavelength is 380 nm or less.
[0053]
A light source for irradiating actinic rays is disposed above the photomask substrate 40 as described above, and actinic rays are emitted from the back surface 41b of the transparent substrate 41 toward the surface 41a. The mask 42 shields actinic rays, but passes through the opening surrounded by the mask 42 and irradiates the photocatalyst film 43 in a portion without the mask 42. Therefore, actinic rays do not enter the region of the wettability variable layer 14 ′ that overlaps the mask 42, that is, the region on the protective insulating film 18, but actinic rays enter the regions that overlap the surrounding regions 19.
When active light passes through the photocatalytic film 43, active oxygen species (.OH) are generated, and this active oxygen species causes a chemical reaction with the wettability variable layer 14 '. In the wettability variable layer 14 ′, active oxygen species that have passed through the photocatalyst film 43 reach a region that overlaps the surrounding regions 19, 19,..., And a region that overlaps the protective insulating film 18 is activated by the mask 42. Reactive oxygen species do not reach because the light is shielded. As described above, the action of the photocatalyst is that active oxygen species are generated when an actinic ray is incident on the photocatalyst film 43, and the generated active oxygen species passes through the gas phase between the photomask substrate 40 and the wettability variable layer 14 ′. The chemical structure of the wettability variable layer 14 ′ is changed by the active oxygen that has diffused and reached the wettability variable layer 14 ′. Since the opening area of the opening surrounded by the mask 42 is slightly larger than the area of the surrounding region 19, the active oxygen species reach slightly outside the surrounding region 19.
[0054]
In the wettability variable layer 14 ′, the region that does not overlap with the mask 42 is replaced with a hydrophilic hydroxyl group by elimination of the Rf group exhibiting liquid repellency by the active oxygen species (.OH) generated by the action of the photocatalyst. As shown in the general formula (23).
[Chemical 3]

This region is the lyophilic region 14a. The lyophilic region 14a is lyophilic with respect to the organic compound-containing liquid because the functional group containing fluorine (above Rf) is decomposed / eliminated and substituted with a hydroxyl group, and constitutes an EL layer 15 described later. This liquid can be uniformly formed on the surface of the lyophilic region 14a without repelling the liquid containing the material to be treated. At this time, in the anodes 13, 13,..., The center line average roughness Ra is 0.5 nm or more and less than half of the thickness of the EL layer 15, and the difference in unevenness is large, and the surface area of the anode 13 per pixel is sufficiently large. The actual area where the wettability variable layer 14 ′ on the surface of the anode 13 is applied is also large.
[0055]
Further, in the lyophilic region 14a, the main chain of the polymer composed of silicon and oxygen is formed in a state along the surface of the anodes 13, 13,. Since it is substituted with a hydroxyl group, the film thickness is also equal to the length of the HO—Si—X— group or HO—Si— group, which is the main chain in this single molecular unit (corresponding to a side chain as a polymer here), It can be very thin as 1 nm or less. Therefore, on the anodes 13, 13,... Where the active oxygen species are generated, the pattern film 14 becomes very thin, and the lyophilic region 14a itself is used for injection and transport of charges such as holes. There is almost no hindrance.
In the wettability variable layer 14 ′, the active enzyme does not reach the region overlapping with the mask 42, so that no chemical change occurs and the liquid containing the material constituting the EL layer 15 is still liquid repellent. . This region is the liquid repellent region 14b. The lyophobic region 14b is formed continuously with the lyophilic region 14a and is thicker than the lyophilic region 14a by the functional group Rf containing substantially fluorine.
[0056]
After the pattern film 14 is formed by partially exposing the wettability variable layer 14 ′ as described above, the EL layer 15 is placed in each surrounding region 19 at least twice the center line average roughness Ra of the anode 13. The film is formed so as to have a film thickness of. The EL layers 15, 15,... Are formed by applying a droplet discharge technique (inkjet technique). That is, as shown in FIG. 4E, the nozzle 70 that can discharge the organic compound-containing liquid containing the constituent material of the EL layer 15 is opposed to the transparent substrate 12, and the driving device applies the transparent substrate 12 to the transparent substrate 12. The nozzle 70 is moved relatively along the horizontal plane, and when the nozzle 70 is positioned on the surrounding area 19, the organic compound-containing liquid is discharged from the nozzle 70 as a droplet once or a plurality of times. As a result, the droplet of the organic compound-containing liquid lands on the pattern film 14 in the surrounding area 19. Note that the organic compound-containing liquid may be prepared for each of red, green, and blue colors, and the colors of the EL layers 15, 15,.
[0057]
The landed droplet spreads in the lyophilic region 14a to form a film, and the film is solidified, whereby the EL layer 15 is formed. Since the pattern film 14 is a lyophilic region 14 a in the surrounding region 19, the landed droplets are likely to get wet and spread easily, and the organic compound-containing liquid spreads throughout the surrounding region 19.
[0058]
In particular, since the center line average roughness Ra of the anodes 13, 13,... Is 0.5 nm or more and less than half the thickness of the EL layer 15, the surface area of the lyophilic region 14a is increased, and Liquid droplets are likely to get wet in the liquid region 14a. This can be explained as follows.
[0059]
Droplet wetting on a solid surface depends on two factors. One is a chemical factor determined by a combination of a substance constituting the solid and a droplet that wets the surface, and the other is a factor of a micro uneven structure on the surface of the solid.
The contact angle θ on the flat surface is determined by the balance between the surface tension of the solid and the droplet and the interfacial tension between the solid and the droplet, and the following Young's equation is established.
γ _s = Γ _SL + Γ _L COSθ (24)
Where γ _S Is the surface tension of the solid, γ _L Is the surface tension of the droplet, γ _SL Is the interfacial tension between the solid and the liquid. The actual surface area is larger than the macroscopic area where the surface is not flat and has a fine uneven structure. If the surface area is increased by r times, it is necessary to multiply r only by the surface tension of the solid and the interfacial tension between the solid and the liquid in formula (24).
COSθ _f = R (γ _S −γ _SL ) / Γ _L ... (25)
Where θ _f Is the contact angle on a rough surface. Since r is always a positive number greater than 1, COSθ depends on whether COSθ is positive, that is, θ <90 °, or whether COSθ is negative, that is, θ> 90 °. _f Is a large positive or negative value. In other words, a surface that gets wet as the surface becomes rougher becomes wetter, and a surface that repels becomes more repellent.
As a result, the lyophilic region 14a becomes more wet.
[0060]
The lyophilic region 14a has a thickness longer than 0 nm and 1 nm or less, and has a large unevenness difference between the center line average roughness Ra of the anode 13 and 0.5 nm or less of the thickness of the EL layer 15. The surface of the liquid region 14a has irregularities and is not smooth. Therefore, since the EL layer 15 is formed so as to mesh with the unevenness of the pattern film 14, peeling between the EL layer 15 and the pattern film 14 hardly occurs. In addition, since the actinic ray is incident slightly outside the surrounding area 19 to form a lyophilic area 14a wider than the surrounding area 19, a droplet that becomes the EL layer 15 in the lyophilic area 14a. Since the contact angle is lowered, the organic compound-containing liquid surely spreads throughout the surrounding area 19. Therefore, the EL layer 15 is formed with a uniform thickness, and peeling between the EL layer 15 and the pattern film 14 is difficult to occur, and the occurrence rate of defects can be suppressed. Furthermore, since the periphery of each lyophilic region 14a is a liquid repellent region 14b, the organic compound-containing liquid does not bleed into the liquid repellent region 14b. Therefore, the organic compound-containing liquids of two adjacent pixels do not mix with each other. Therefore, the EL layers 15, 15,... Can always be formed with a uniform thickness, and color development with high color purity can be achieved when two adjacent pixels are organic compound-containing liquids having different emission colors.
[0061]
In addition, when the EL layer 15 has a laminated structure, an organic compound-containing liquid is prepared for each layer, and each organic compound-containing liquid is sequentially ejected into the surrounding area 19 with a nozzle to laminate each layer. I will do it. For example, in the case where the EL layer 15 has a two-layer structure including a hole injection layer and a light-emitting layer in a narrow sense, an organic compound-containing liquid for the hole injection layer (an organic compound constituting the hole injection layer (for example, a conductive high A hole injection layer is formed by discharging a dispersion liquid in which PEDOT (polythiophene) which is a molecule and PSS (polystyrene sulfonic acid) which is a dopant are dispersed in an aqueous solvent into each surrounding region 19, The EL layer 15 is formed by discharging an organic compound-containing liquid in a narrow light-emitting layer (a solution in which a polyfluorene-based light-emitting material is dissolved in an organic solvent such as toluene, xylene, or tetralin) into each surrounding region 19. Even in this case, the organic compound-containing liquid in the hole injection layer is familiar in each lyophilic region 14a of the pattern film 14, and the organic compound-containing liquid in the hole injection layer is repelled in the liquid repellent region 14b.
[0062]
Next, the remaining solvent is removed by drying with a hot plate in a nitrogen atmosphere or drying with a sheathed heater in vacuum. Next, the cathode 16 is formed on one surface so as to cover the EL layers 15, 15,... By a film formation method such as a PVD method and a CVD method such as vapor deposition and sputtering (FIG. 4E). Since the EL layer 15 is formed over the entire surrounding region 19, the cathode 16 does not directly contact the anode 13, and the cathode 16 and the anode 13 do not short-circuit. After the cathode 16 is formed, the organic EL elements 11, 11,... Are sealed with a sealing material such as sealing resin and sealing glass. It is desirable to apply a curable adhesive and attach the sealing substrate to the cathode 16 side.
[0063]
In the organic EL display panel 10 manufactured as described above, a current flows through the organic EL element 11 in accordance with a signal input by the pixel circuit via the signal line 51 and the scanning line 52. In the organic EL element 11, current flows when holes are injected from the anode 13 into the EL layer 15 and electrons are injected from the cathode 16 into the EL layer 15. Then, holes and electrons are transported in the EL layer 15, and the holes and electrons are recombined in the EL layer 15, whereby the EL layer 15 emits light. Since the anodes 13, 13,... And the transparent substrate 12 are transparent, the light emitted from the EL layer 15 is emitted from the back surface 12b of the transparent substrate 12, and the back surface 12b becomes the display surface.
[0064]
As described above, in the present embodiment, the wettability variable layer 14 ′ is formed by hydrolyzing and polymerizing the silazane compound, and the main chain as a polymer composed of silicon and oxygen is the anodes 13 and 13. ,... And the protective insulating film 18 are formed on the entire surface along the surface, and the substantial thickness of the lyophilic region 14a in each surrounding region 19 is the main molecular unit in the wettable variable layer 14 ′. The thickness is very thin, excluding the functional group Rf containing fluorine from the chain. Therefore, even if the pattern film 14 is interposed between the anode 13 and the EL layer 15, the insulation of the pattern film 14 can be ignored, and injection of holes from the anode 13 to the EL layer 15 is not hindered. . In the anodes 13, 13,..., The center line average roughness Ra is 0.5 nm or more and less than half of the thickness of the EL layer 15, and the difference in unevenness is large. Therefore, the actual area where the wettability variable layer 14 ′ is applied is also large. Therefore, the contact area between the wettability variable layer 14 ′ and the EL layer 15 is inevitably increased. Therefore, since the actual area for injecting holes from the wettability variable layer 14 ′ to the EL layer 15 is also large, the luminance (cd / m ² ) Can be improved.
[0065]
Further, since oxygen plasma cleaning or ultraviolet / ozone cleaning is performed before the wettability variable layer 14 ′ is formed, and further cleaning with pure water is performed, a very thin wettability variable layer 14 ′ having liquid repellency can be easily obtained. It can be formed into a film. In particular, since the substrate is washed with pure water, the liquid-repellent wettability variable layer 14 ′ can be reliably formed on the protective insulating film 18. This is because the liquid-repellent wettability variable layer 14 ′ may not be sufficiently formed on the protective insulating film 18 when it is not cleaned with pure water. Hydrolysis polymerization reaction of the silazane compound is caused by water molecules attached to 18 surface layers.
[0066]
Further, in the present embodiment, the wettability variable layer 14 ′ is partially contained by irradiating the wettability variable layer 14 ′ with the active oxygen species through the photomask substrate 40 without containing the photocatalyst in the wettability variable layer 14 ′. To react. In the wettability variable layer 14 ′, the region irradiated with actinic rays becomes the lyophilic region 14 a, and injection of holes from the anode 13 to the EL layer 15 is not hindered, and the pattern film 14 becomes the EL layer 15. There is no chemical effect.
[0067]
Further, the region irradiated with actinic rays in the wettability variable layer 14 ′ becomes the lyophilic region 14a, and the centerline average roughness Ra of the portion overlapping the anode 13 in the lyophilic region 14a is particularly 0. Since the thickness is 0.5 nm or more and less than half of the thickness of the EL layer 15, the EL layer 15 is easily wetted, so that the EL layer 15 spreads over the entire surrounding region 19. As a result, the EL layer 15 is formed uniformly over the entire surrounding region 19, so that no short circuit occurs between the anode and the cathode. Further, since peeling does not easily occur between the EL layer 15 and the pattern film 14, dark spots are not easily generated in the emitted EL layer 15.
[0068]
In the above description, the anode 13 is formed by the EB vapor deposition method so that the center line average roughness Ra is 0.5 nm or more and half or less of the thickness of the EL layer 15. The anode 13 having a center line average roughness Ra of 0.5 nm or more and half or less of the thickness of the EL layer 15 may be formed by any one of the methods.
[0069]
[Another method (1)]
When patterning the transistors 21, 21,..., A transparent conductive material made of indium oxide, zinc oxide, tin oxide, or a mixture containing at least one of them (for example, tin-doped indium oxide (ITO), zinc-doped indium oxide). The layer is formed on the entire surface of the gate insulating film 23. If the center line average roughness Ra is not less than 0.5 nm and not more than half of the thickness of the EL layer 15, the film formation method is not limited to the EB vapor deposition method. It may be a plating method, a sputtering method, other PVD methods, or a CVD method. After the transparent conductive layer is formed, a mask is applied to the transparent conductive layer, the shape of the transparent conductive layer is processed according to the mask, and the mask is removed, whereby the anodes 13, 13,... Are patterned in a matrix (FIG. 3A). .
[0070]
After forming the anodes 13, 13,... And the transistors 21, 21,..., A mesh-like protective insulating film 18 is formed so as to surround the anodes 13, 13,. ).
[0071]
Next, by performing soft etching on the exposed portions of the anodes 13, 13,..., The center line average roughness Ra of the surfaces of the anodes 13, 13,. The EL layer 15 is formed to be less than half the thickness.
Then, the pattern film 14, the EL layers 15, 15,..., And the cathode 16 are formed in the same manner as described above.
In this method, the formation method of the anodes 13, 13,... Is not limited to the EB vapor deposition method, so the degree of freedom of the formation method of the anodes 13, 13,.
[0072]
[Another method (2)]
When patterning the transistors 21, 21,..., Indium oxide, zinc oxide, tin oxide or a mixture containing at least one of them (for example, tin-doped indium oxide (ITO), zinc-doped) by PVD or CVD. A transparent conductive layer made of indium oxide) is formed over the gate insulating film 23. After the transparent conductive layer is formed, a mask is applied to the transparent conductive layer, the shape of the transparent conductive layer is processed according to the mask, and the mask is removed, whereby the anodes 13, 13,... Are patterned in a matrix (FIG. 3A). . After forming the anodes 13, 13,... And the transistors 21, 21,..., A mesh-like protective insulating film 18 is formed so as to surround the anodes 13, 13,. ).
[0073]
Then, a blasting material such as silica sand is blown toward the exposed portions of the anodes 13, 13,... (Blasting method), so that the center line average roughness Ra of the surfaces of the anodes 13, 13,. The EL layer 15 is formed to be less than half the thickness. A blasting method using silica sand as a blasting material is particularly called a sandblasting method. Next, the blast material adhering to the surfaces of the anodes 13, 13,.
Then, the pattern film 14, the EL layers 15, 15,..., And the cathode 16 are formed in the same manner as described above.
Since the blasting method as described above can be performed without using chemicals, there is no problem of disposal / treatment of chemicals.
[0074]
[Another method (3)]
When patterning the transistors 21, 21,..., Indium oxide, zinc oxide, tin oxide or a mixture containing at least one of them (for example, tin-doped indium oxide (ITO), zinc-doped) by PVD or CVD. A transparent conductive layer made of indium oxide) is formed over the gate insulating film 23. After the transparent conductive layer is formed, a mask is applied to the transparent conductive layer, the shape of the transparent conductive layer is processed according to the mask, and the mask is removed, whereby the anodes 13, 13,... Are patterned in a matrix (FIG. 3A). . After forming the anodes 13, 13,... And the transistors 21, 21,..., A mesh-like protective insulating film 18 is formed so as to surround the anodes 13, 13,. ).
[0075]
Next, the exposed portions of the anodes 13, 13,. ₂ O _Three TiO ₂ , SiO ₂ An inorganic material such as 10 to 20 Å (angstrom) is formed by sputtering. Since the film thickness of the inorganic layer is very thin, 10 to 20 mm, the film has defects in some places and is not continuous. Then, wet etching or dry etching is performed on the anodes 13, 13,... Using the inorganic layer as a mask, and the surface of the anodes 13, 13,... Has a center line average roughness Ra of 0.5 nm or more. It is formed so as to be less than half of that. The inorganic layer may not be removed after the etching.
Then, the pattern film 14, the EL layers 15, 15,..., And the cathode 16 are formed in the same manner as described above.
In this method, since the mask of the inorganic layer is provided on the anodes 13, 13,..., The restrictions on the etching method and etching conditions are relaxed, and the environment in which the anodes 13, 13,. Not limited.
[0076]
The present invention is not limited to the above embodiment, and various improvements and design changes may be made without departing from the spirit of the present invention.
For example, since the organic EL display panel 1 of the above embodiment is a self-luminous type, it can be used for a line scanning mechanism of an image forming apparatus such as a page printer.
In the above description, the cathode 16 is common to all the organic organic EL elements 11, 11,..., But the cathode and the anode are changed to form a cathode for each pixel of the organic organic EL element 11. Also good.
Further, instead of the plate-like transparent substrate 12, a sheet-like transparent film substrate may be used.
[0077]
In the above description, the plurality of EL layers 15, 15,... Are patterned by the droplet discharge method. However, since the lyophilic regions 14a, 14a,... Are patterned in a matrix in the pattern film 14, the organic compound-containing liquid is applied to the pattern film 14 and the transparent substrate 12 is rotated (spin coating method). The plurality of EL layers 15, 15,... Can be patterned in a matrix. Further, by utilizing the lyophilic and liquid repellent patterning of the pattern film 14, the plurality of EL layers 15, 15,... May be patterned in a matrix by a dip coating method or a die coating method. Furthermore, the plurality of EL layers 15, 15,... May be patterned in a matrix using a planographic printing method, an intaglio printing method, or a relief printing method.
[0078]
In the above description, the wettability variable layer 14 ′ is formed by the dip coating method. However, the wettability variable layer 14 ′ may be formed by the spin coating method, the brush coating method, or the vapor deposition method.
[0079]
In the above description, the wettability variable layer 14 ′ does not contain a photocatalyst, but the wettability variable layer 14 ′ may contain a photocatalyst by applying a silazane-based solution containing a photocatalyst. In this case, the photocatalyst film 43 may not be provided on the photomask substrate 40.
[0080]
Moreover, although the silazane compound was mentioned as a silane compound which has a functional group containing a fluorine, other silane compounds, such as a silane coupling agent (hydroalkyl-polymerizable silicon compound containing hydrolytic polymerization), and other liquid repellency are shown. It may be a functional group, and the substituted functional group may be a lyophilic functional group other than a hydroxyl group.
[0081]
Further, after the protective insulating film 18 is patterned and before the wettability variable layer 14 ′ is formed, the mesh-like partition wall 20 is patterned so as to overlap the protective insulating film 18 as shown in FIG. May be. The width of the partition wall 20 increases as it approaches the transparent substrate 12 and is narrower than the width of the protective insulating film 18. The partition wall 20 has insulating properties and is formed of a resin such as a polyimide resin, a novolac resin, or an acrylic resin.
[0082]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples.
In the first example, as described in the above embodiment, the anodes 13, 13,... Made of ITO were formed by EB vapor deposition. The center line average roughness Ra of the anodes 13, 13,... Was measured with an atomic force microscope (AFM) as a cut-off value of 12.5 μ along the formula (b), and found to be 10.5 nm. In this case, before the exposure using the photomask substrate 40, the organic compound-containing liquid is dropped on the wettability variable layer 14 ′ that overlaps the anode 13 (showing liquid repellency). The contact angle of was measured. Further, after exposure using the photomask substrate 40, an organic compound was dropped onto the lyophilic region 14a overlapping the anode 13, and the contact angle of the organic compound-containing liquid was measured. As the organic compound-containing liquid, a solution obtained by adding ethanol to a dispersion liquid in which PEDOT and PSS are dispersed in an aqueous solvent (organic compound-containing liquid No. 1), and organic compound-containing liquid No. What added the addition amount of ethanol to 2 times (organic compound containing liquid No. 2) rather than 1 was used. Organic compound-containing liquid No. The weight ratio of water: ethanol: PEDOT and PSS = 94.25 wt%: 5 wt%: 0.75 wt%. The weight ratio of 2 is water: ethanol: PEDOT and PSS = 89.25 wt%: 10 wt%: 0.75 wt%. The reason why ethanol is added to the organic compound-containing liquid is that unless the ethanol is added, the viscosity of the dispersion is high, and the dispersion cannot be continuously applied by a droplet discharge method using an inkjet head. Organic compound-containing liquid No. 1 is the lower limit that can be put to practical use by the droplet discharge method. If the addition amount is less than 1, droplets cannot be discharged continuously by the droplet discharge method.
[0083]
In the second embodiment, the anodes 13, 13,... Were formed by the HDAP-IP method (ion plating method), and the center line average roughness Ra of the anodes 13, 13,. In the third embodiment, the anodes 13, 13,... Were formed by sputtering, and the center line average roughness Ra of the anodes 13, 13,. Then, in the same manner as in the example, the organic compound-containing liquid is dropped on the portion of the wettability variable layer 14 ′ before exposure that overlaps the anode 13 (showing liquid repellency), and the contact angle of the organic compound-containing liquid is set. In addition to the measurement, an organic compound was dropped onto the lyophilic region 14a that overlapped the anode 13 after exposure, and the contact angle of the organic compound-containing liquid was measured.
The measurement results are shown in Table 1.
[0084]
[Table 1]

[0085]
As can be seen from Table 1, when the contact angle after exposure is compared, in the case of the HDAP-IP method, in the case of the sputtering method, the contact angle becomes smaller in the order of the EB vapor deposition method. It can be seen that the organic compound-containing liquid is most easily wetted in the lyophilic region 14a when the film is formed.
In addition, in the case of the EB vapor deposition method, it can be seen that the contact angle is the largest before exposure and the organic compound-containing liquid is most easily repelled as compared with other methods. Furthermore, in the case of the EB vapor deposition method, it can be seen that the change rate of the contact angle is the largest between before exposure and after exposure as compared with other methods.
In any case, it was confirmed that the contact angle of the lyophilic region 14a was 25 ° or less, which was effective for the film formation of the organic compound-containing liquid. Particularly, in the EB vapor deposition method, the center line average roughness Ra is 10 nm or more, the contact angle of the lyophilic region 14a is 15 ° or less, and the contact angle is remarkably improved. Further, since the contact angle of the liquid repellent region 14b exceeds 110 °, the EL layer 15 can be formed with high accuracy.
[0086]
【The invention's effect】
According to the present invention, since the surface roughness Ra of the first electrode is large, the lyophilic film formed on the first electrode, the portion formed on the first electrode and irradiated with active light is more It is easy to become familiar with the organic compound-containing liquid, and the organic compound-containing liquid wets better. For this reason, the organic compound-containing liquid oozes over the lyophilic film or the entire exposed portion, and the formation failure of the EL layer can be suppressed.
[Brief description of the drawings]
FIG. 1 is a plan view showing an organic EL display panel to which the present invention is applied.
FIG. 2 is a cross-sectional view of the organic EL display panel shown in FIG.
3 is a view showing a manufacturing process of the organic EL display panel shown in FIG. 1;
4 is a drawing showing manufacturing steps subsequent to FIG. 3. FIG.
5 is a cross-sectional view showing an organic EL display panel different from the organic EL display panel shown in FIG.
[Explanation of symbols]
10 Organic EL display panel (Organic EL panel)
11 Organic EL device
12 Transparent substrate (substrate)
13 Anode (first electrode)
14 'wettability variable layer
14 Pattern film
14a lyophilic region (lyophilic membrane)
14b Liquid repellent area
15 EL layer
16 Cathode (second electrode)

Claims (10)

In the method for producing an organic EL element, an organic EL element is produced by laminating a first electrode, at least one EL layer, and a second electrode in this order on a substrate.
A first electrode forming step of forming the first electrode on the substrate having a surface roughness Ra of 0.5 nm or more and half or less of the thickness of the EL layer;
Forming a lyophilic film on the first electrode that is compatible with the organic compound-containing liquid containing the material of the EL layer;
Forming the EL layer by applying the organic compound-containing liquid on the lyophilic film;
The manufacturing method of the organic EL element characterized by including. The first electrode forming step includes a step of forming the first electrode having a surface roughness Ra of 0.5 nm or more and half or less of a thickness of the EL layer by an EB vapor deposition method. The manufacturing method of the organic EL element of description. In the first electrode forming step, the step of forming the first electrode, and then performing soft etching on the first electrode, the surface roughness Ra of the first electrode is 0.5 nm or more of the EL layer. The method of forming the organic EL element according to claim 1, comprising a step of forming the half of the thickness or less. The first electrode forming step includes a step of forming the first electrode, and then performing a blasting method on the first electrode, whereby the surface roughness Ra of the first electrode is 0.5 nm or more. The method for forming an organic EL element according to claim 1, further comprising: forming the layer to be half or less of the thickness of the layer. The first electrode forming step includes a step of forming the first electrode, a step of forming a 10 to 20 mm thick inorganic layer on the first electrode, and a step of forming the first electrode using the inorganic layer as a mask. The method of manufacturing an organic EL element according to claim 1, further comprising: etching one electrode. In an organic EL panel manufacturing method for manufacturing an organic EL panel in which a plurality of organic EL elements are arranged on a substrate,
A first electrode forming step of forming a plurality of first electrodes having a surface roughness Ra of 0.5 nm or more on the substrate at an interval;
Forming a wettability variable layer that improves wettability with respect to the organic compound-containing liquid by irradiation with actinic rays so as to cover the plurality of first electrodes together;
Irradiating a region of the wettability variable layer overlapping each first electrode with an actinic ray for modifying the wettability variable layer;
By applying an organic compound-containing liquid to a region of the wettability variable layer that overlaps each of the first electrodes, on each of the first electrodes, the thickness is at least twice the surface roughness Ra. Forming one or more EL layers;
The manufacturing method of the organic electroluminescent panel characterized by including. The first electrode forming step includes a step of forming the plurality of first electrodes having a surface roughness Ra of 0.5 nm or more and half or less of a thickness of the EL layer by an EB vapor deposition method. Item 7. A method for producing an organic EL panel according to Item 6. In the first electrode forming step, the surface roughness Ra of the plurality of first electrodes is set to 0. 0 by forming the plurality of first electrodes and then performing soft etching on the plurality of first electrodes. The method for forming the organic EL panel according to claim 6, further comprising: forming a thickness of 5 nm or more and half or less of the thickness of the EL layer. In the first electrode forming step, the surface roughness Ra of the plurality of first electrodes is determined by performing a blasting process on the plurality of first electrodes after the step of forming the plurality of first electrodes. The method for forming an organic EL panel according to claim 6, further comprising: forming a thickness of 0.5 nm or more and half or less of the thickness of the EL layer. The first electrode forming step includes a step of forming the plurality of first electrodes, a step of forming a 10 to 20 mm thick inorganic layer on the plurality of first electrodes, and a step of forming the inorganic layer. And etching the plurality of first electrodes as a mask to form a surface roughness Ra of the plurality of first electrodes to 0.5 nm or more and half or less of the thickness of the EL layer. The manufacturing method of the organic electroluminescent panel of Claim 6.

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