JP4688115B2

JP4688115B2 - Method for forming film in liquid phase

Info

Publication number: JP4688115B2
Application number: JP33847899A
Authority: JP
Inventors: 正美粂井; 真奈美佐野; 秀一安食
Original assignee: Stanley Electric Co Ltd
Current assignee: Stanley Electric Co Ltd
Priority date: 1999-11-29
Filing date: 1999-11-29
Publication date: 2011-05-25
Anticipated expiration: 2019-11-29
Also published as: JP2001158621A

Description

【０００１】
【発明の属する技術分野】
本発明は、液相下での基材表面への被膜の形成方法に関し、特に、反応液中での加水分解反応による酸化物被膜の形成に好適な被膜形成方法に関わる。
【０００２】
【従来の技術】
チタンフッ化アンモニウムを含む水溶液に、水溶液中の下記化学式１の平衡を右に進める添加剤を添加して調整した酸化チタンの過飽和水溶液に、任意の形状の基材（糸状、板状、壷状など）を接触させることにより、基材表面に酸化チタンの薄膜を形成することが特許番号第２７８５４３３号、特許番号第２７２０５６８号、特許番号第２７８５４６７号及び特開平１０−１５８０１４号公報などに提案されている。
【０００３】
【化１】

【０００４】
ケイフッ化アンモニウムを含む水溶液に、水溶液中の下記化学式２の平衡を右に進める添加剤を添加して調整した酸化ケイ素の過飽和水溶液に、任意の形状の基材（糸状、板状、壷状など）を接触させることにより、基材表面に酸化ケイ素の薄膜を形成することが特開平１０−１５８０１０号公報に提案されている。
【０００５】
【化２】

【０００６】
チタンフッ化水素を含む水溶液に、水溶液中の下記化学式３の平衡を右に進める添加剤を添加して調整した酸化チタンの過飽和水溶液に、任意の形状の基材（糸状、板状、壷状など）を接触させることにより、基材表面に酸化チタンの薄膜を形成することが特公平７−３５２６８号公報及び特公平３−６７９７８号公報に提案されている。
【０００７】
【化３】

【０００８】
ケイフッ化水素を含む水溶液に、水溶液中の下記化学式４の平衡を右に進める添加剤を添加して調整した酸化ケイ素の過飽和水溶液に、任意の形状の基材（糸状、板状、壷状など）を接触させることにより、基材表面に酸化ケイ素の薄膜を形成することが特開昭６４−２８３７６号公報に提案されている。
【０００９】
【化４】

【００１０】
これらの金属酸化物薄膜の形成法は、
(1)比較的低温での成膜が可能である。
(2)安価な成膜法である。
(3)水溶媒を用いているために、工程中で有機溶剤が揮発することによる環境汚染などが少なく、いわゆる環境にやさしい成膜法である。
(4)複雑な表面形状の基材や細管の内壁など、真空を用いた成膜が難しい基材に対しても均一な成膜が可能である。
などの特徴を有する。これらの被膜成法では、反応溶液中に基材を浸漬することにより反応液と基材とを接触させ、基材の表面に被膜を形成している。
【００１１】
これらの被膜形成法は、ヘキサフルオロ金属酸（または塩）の加水分解による酸化物生成反応に基づいており、加水分解を促進させるためにホウ酸、塩化アルミニウム、アルミニュウム金属などを加えて被膜形成を行わせている。
【００１２】
図６に従来の技術による基材への被膜形成方法を行う反応装置の構造の一例を断面図で示す。反応槽（反応容器）１内に、上記文献で記載のような反応液２が満たされており、その反応液中に被膜を形成しようとする任意の形状の基材３が浸漬されている。反応槽１の外側には反応液全体の温度を一定にして、反応速度を一定に保ったり、あるいは反応液全体を加熱して反応速度を高める目的のための調温器１４が配置されている。調温器１４はたとえば、ヒータであり、また調温器の代わりに、温浴あるいは水浴装置なども使用される。
【００１３】
これら文献に記載された温度制御というのは、成膜速度を促進する目的で、反応液全体を加熱(温める)ことであり、加熱制御温度は室温以上の温度範囲である。また、特開昭６４−２８３７６号公報には、被膜の組成制御を目的として、加熱ではなく反応液全体を冷却することが開示されている。
【００１４】
【発明が解決しようとする課題】
上述の文献に記載の被膜形成法においては、得られる酸化物被膜は基材表面以外に、反応容器の壁面にも形成されてしまう。さらに加えて、基材表面以外の反応液中でこれら酸化物の微粒子が同時に生成してしまう。その理由は、反応容器の中の反応液条件（組成、濃度、温度など）が同一であれば、酸化物生成反応が反応液全体で同時に進行するためである。
【００１５】
反応容器の壁面に形成されてそこから剥離した酸化物被膜の一部や、反応液中に生成された酸化物微粒子は、反応液の対流や振動などにより反応液中を拡散し、基材に付着するなどして基材の均一な被膜形成に不都合を生じる場合があった。また、これら被膜形成時に生じる不必要な微粒子は、さらに反応の核として働くために、酸化物微粒子の生成をさらに助長することになり、悪循環となる。
【００１６】
このように目的とする基材表面以外の部分に被膜が形成されたり、成膜に関与しない不必要な微粒子が生成したりする結果、本来の目的である基材表面への酸化物被膜形成の効率が低下する傾向にあった。
【００１７】
本発明の目的は、反応液中において、被膜形成に直接関与しない不要な微粒子生成反応を低減し、また基材表面以外への被膜形成を抑制して、基材表面における被膜形成に関与した反応だけを優先的に促進させようとする被膜形成方法を提供することである。
【００１８】
【課題を解決するための手段】
上述の文献で提案されている被薄膜形成方の中には、図６のように反応液全体を温度制御することについて述べられたものがある。しかし、これら文献には、成膜の対象物である基材の温度の制御や、基材近傍だけに限定した反応液の温度のいずれの温度制御についてもまったく考慮も検討もされておらず、温度制御の効果についても明らかでない。
【００１９】
本発明の液相での被膜形成方法は、被膜材料の化合物を含む反応液中に前記反応液の温度よりも高い温度に保った基材を浸漬して、前記基材と前記反応液とを接触させ、前記基材の表面とその近傍で選択的に前記化合物の化学反応を進行させて前記基材の表面に前記被膜材料を析出させて被膜を形成する工程を有する。
【００２０】
本発明の実施例においては、基材表面における被膜形成に関与した反応だけを優先的に促進させるために、基材及び反応容器（反応液）において、被膜形成に直接関わる部位と、直接関わらない部位とにおいて選択的に個別の温度制御を施すことにより、基材表面とその近傍とをそれ以外の反応液の温度よりも高くなるように温度制御する。
【００２１】
【実施例】
次に、本発明による被膜形成方法の実施例の幾つかについて図１から図５を参照しつつ説明する。
【００２２】
図１に本発明の実施例による基材への被膜形成方法を実施するための反応装置の構造を断面図で示す。反応槽（反応容器）１内に、例えば，前述した文献で記載のような被膜材料の化合物を含む反応液２が満たされており、その反応液中に被膜を形成しようとする任意の形状の基材３の一部が浸漬されている。反応槽１の外側には反応液の温度を制御する調温器（または温調材）４が配置されている。調温器４はたとえば、冷却器（クーラ）であり、反応槽１を冷却して反応液２の温度を低下させる。また冷却器の代わりに、水浴装置あるいは冷却媒体を配置してもよい。さらに基材３の反応液２とは接触してない側の表面にもう一つの調温器５が配置されている。この調温器５はたとえば、ヒータであり、基材３を加熱して所望の温度に調整し、反応液２に接した基材表面での成膜を促進する目的で設ける。なお、調温器５としては、ヒータの代わりに、温水浴等加熱媒体を接触させる方法あるいは光、電波などのエネルギの照射による方法を使用することもできる。
【００２３】
図１の装置において、はじめに、反応液２と反応槽１を調温器４で反応液の化学反応がよく働く温度条件よりも低い温度に冷却し、反応液２を低温に保持する。これにより、反応液中における酸化物粒子の生成、反応槽内壁への被膜形成速度をかなり低く保つことができる。
【００２４】
次に、被膜を形成しようとする基材３の表面を反応液２に浸して接触させる。そして、反応液に接触している側とは反対側に配置された調温器５で基材３を加熱して基材３の温度を上げて、反応液２の温度よりも高くなるように温度制御する。基材３に与えられた熱は接触している基材近傍の反応液２に伝達されて、基材近傍の反応液２の温度はその周囲の反応液２の温度よりも高くなる。基材３への加熱期間（加熱開始時期）は、基材３を反応液２に接触させる前にあらかじめ所定温度に加熱しておいてもよいし、接触させる途中であってもよいし、完全に接触が完了した後に開始してもよいし、あるいはそれらの組み合わせでもよく、基材３の形状や材料あるいは希望する被膜の条件などにより適宜最良の加熱期間を選択すればよい。
【００２５】
基材３に伝達させる熱は、反応液２に接した基材表面の温度が最初に冷却した反応液２の温度よりも高くなるようであればよく、周囲の温度よりも高くなった基材３の表面とその近傍で反応液２の被膜形成反応が促進されて被膜形成速度を高める。それと同時に、被膜形成に直接関わらない反応槽１の内壁と、基材３の表面から遠い反応液２は冷却されて低温度であるので、不必要な被膜形成や、微粒子の形成は起こりにくい。このため必要な基材表面のみに効率的に被膜形成反応が進む。
【００２６】
図２に本発明の他の実施例による基材への被膜形成方法を実施するための反応装置の構造を断面図で示す。反応槽１、反応液２、調温器４については図１の実施例と同様である。基材３１は内部に空洞、図示の場合断面が十字形の空洞を有しており、この空洞の内外にもう一つの調温器６が配置されている。この調温器６はたとえば、空洞内に挿入できるような小型のヒータであり、基材３１を内部から加熱して所望の温度に調整し、反応液２に接した基材外側表面での成膜を促進する目的で設ける。なお、調温器５としては、ヒータの代わりに、温水あるいは他の加熱媒体を空洞内に充填して加熱することもできる。
【００２７】
図３に本発明の別の実施例による基材への被膜形成方法を実施するための反応装置の構造を断面図で示す。反応槽１、反応液２、調温器４については図１の実施例と同様である。基材３２は内部に断面が円形の空洞を有するチューブ状の形状であり、この空洞内外に温水あるいは他の加熱媒体７を流して加熱する。加熱媒体７の代わりに、空洞内に挿入できるようなヒータを配置することもできる。加熱媒体７により、チューブ状基材３２を内部から加熱して所望の温度に調整し、反応液２に接した基材外側表面での成膜を促進する。
【００２８】
図４に本発明のさらに別の実施例による基材への被膜形成方法を実施するための反応装置の構造を断面図で示す。図４の（Ｂ）は（Ａ）のＩ−Ｉ’における断面図である。この実施例では、基材３３は図３の実施例と同様に内部に断面が円形の空洞を有するチューブ形状である。図３の例と異なる点は、この基材３３の空洞側の内壁に被膜を形成することである。従って、反応液２はこの空洞内を流れるようにされる。基材３３は反応槽１０に固定部材１１で固定される。反応槽１０の内部には温水あるいは他の加熱媒体８が満たされている。加熱媒体８とヒータ(図示せず。)とを併用してもよい。加熱媒体８により、チューブ状基材３３を外側から加熱して所望の温度に調整し、反応液２に接した基材内側表面での成膜を促進する。
【００２９】
一方、反応液２は反応槽１０とはべつに設けた調温槽９に貯められている。調温槽９はたとえば、冷却器（クーラ）であり、反応液２を冷却して低温度にする。低温にされた反応液２は連絡配管１２を通って基材３３の空洞に流れ込む。流れ込んだ反応液２は加熱された基材３３の内壁と接触して被膜形成がすみやかに行われる。余分な反応液２は排出配管１３から外部に放出されるか、あるいは調温槽９に戻るように循環する。
【００３０】
図５は、本発明の実施例の被膜形成方法により実際に基材表面に被膜形成を行った場合の成膜時間(横軸)と膜厚(縦軸)との関係を測定したグラフ（黒丸）である。比較のために、図６の従来の技術による被膜形成の場合のカーブ（□でプロット）も示す。
【００３１】
０．１モル／リットルの（ＮＨ₄）₂ＴｉＦ₆（チタンフッ化アンモニウム）に加水分解を促す添加剤として０．３モル／リットルのＨ₃ＢＯ₃を添加して調整した酸化チタンの過飽和水溶液に基材を接触させることにより酸化チタンの被膜を形成した。本発明の実施例では、基材を６０℃に加熱し、２６ｍｌの反応液は０℃に冷却して基材側の温度を高くした。比較の従来の方法では、基材側に特に加熱処理はせず、２６ｍｌの反応液は６０℃に加熱した（基材もほぼ６０℃に近くなる）。
【００３２】
図５のグラフから明らかなように、本発明の実施例による被膜形成方法では、膜厚は最初からぼぼ成膜時間に比例して増加し、２０時間経過後からやや傾きがゆるくなるもののその後も増加傾向が続く。一方、従来の方法では、７〜８時間まではごくゆるやかな膜厚の増加傾向はみられるものの、それ以降は時間をかけても膜厚の増加はほとんどみられなかった。これは、本発明の実施例では、反応槽の内壁への不必要な被膜形成や、反応液内での微粒子の形成が効果的に抑制され、基材表面のみで被膜形成反応が優先的に行われたためであると考えられる。
【００３３】
上述の液相での被膜形成方法は、高温で反応が促進されるものであればよく、加水分解反応に限らない。ガラス基板への光学薄膜、光干渉フィルター、汚染防止膜、あるいは防曇膜の形成、また、太陽電池での被膜形成、誘電体膜、コンデンサ、圧電素子、各種表示素子、ディスプレー装置などへの被膜形成に利用することができる。
【００３４】
以上、実施例に沿って本発明を説明したが、本発明はこれらに制限されるものではない。例えば、種々の変更、改良、組み合わせが可能なことは当業者に自明であろう。
【００３５】
【発明の効果】
以上説明したように、本発明によれば、基材表面における被膜形成に関与した反応だけを優先的に促進させる。基材及び反応容器（反応液）において、被膜形成に直接関わる部位と、直接関わらない部位とにおいて選択的に個別の温度制御を施す。基材表面とその近傍とをそれ以外の反応液の温度よりも高くなるように温度制御することによって、被膜形成に直接関わらない反応槽の内壁と、基材の表面から遠い反応液は低温度に保つ。不必要な被膜形成や、微粒子の形成は起こりにくいために、必要な基材表面のみに効率的に被膜形成反応が進む。さらに、反応液中の微粒子の発生が低減されるために、拡散した微粒子による基板上の生成被膜への悪影響を抑制することができる。
【図面の簡単な説明】
【図１】本発明の実施例による液相での被膜形成方法を実施するための装置の断面図である。
【図２】本発明の他の実施例による液相での被膜形成方法を実施するための装置の断面図である。
【図３】本発明の別の実施例による液相での被膜形成方法を実施するための装置の断面図である。
【図４】本発明のさらに別の実施例による液相での被膜形成方法を実施するための装置の断面図である。
【図５】本発明の実施例による被膜形成方法の成膜時間と膜厚との関係を従来の被膜形成方法の場合と比較して示すグラフである。
【図６】従来の技術による液相での被膜形成方法を実施するための装置の断面図である。
【符号の説明】
１反応槽（反応容器）
２反応溶液
３、３１，３２，３３基材（被膜形成対象物）
４調温器
５調温器
６調温器
７、８加熱媒体
９調温器
１０反応槽
１１固定部材
１２連絡配管
１３排出配管
１４調温器[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for forming a film on a substrate surface under a liquid phase, and particularly relates to a film forming method suitable for forming an oxide film by a hydrolysis reaction in a reaction liquid.
[0002]
[Prior art]
To a supersaturated aqueous solution of titanium oxide prepared by adding an additive that promotes the equilibrium of the following chemical formula 1 in the aqueous solution to an aqueous solution containing ammonium titanium fluoride, a base material of any shape (thread-like, plate-like, hook-like, etc.) ) Is contacted to form a thin film of titanium oxide on the surface of the substrate, which is proposed in Japanese Patent No. 2785433, Japanese Patent No. 2720568, Japanese Patent No. 2785467, and Japanese Patent Laid-Open No. 10-158014. Yes.
[0003]
[Chemical 1]

[0004]
To a supersaturated aqueous solution of silicon oxide prepared by adding an additive that moves the equilibrium of the following chemical formula 2 in the aqueous solution to the right in an aqueous solution containing ammonium silicofluoride, a substrate of any shape (thread, plate, hook, etc.) No. 10-158010 proposes forming a thin film of silicon oxide on the surface of the substrate by contacting the substrate.
[0005]
[Chemical 2]

[0006]
To a supersaturated aqueous solution of titanium oxide prepared by adding an additive that moves the equilibrium of the following chemical formula 3 in the aqueous solution to the right in an aqueous solution containing titanium hydrogen fluoride, a base material of any shape (thread-like, plate-like, hook-like, etc.) In Japanese Patent Publication No. 7-35268 and Japanese Patent Publication No. 3-67978 have been proposed.
[0007]
[Chemical 3]

[0008]
To a supersaturated aqueous solution of silicon oxide prepared by adding an additive that moves the equilibrium of the following chemical formula 4 in the aqueous solution to the right in an aqueous solution containing hydrogen silicofluoride, a base material of any shape (thread-like, plate-like, hook-like, etc.) Japanese Patent Laid-Open No. 64-28376 proposes that a silicon oxide thin film be formed on the surface of a substrate by contacting the substrate.
[0009]
[Formula 4]

[0010]
The method of forming these metal oxide thin films is
(1) Film formation at a relatively low temperature is possible.
(2) An inexpensive film formation method.
(3) Since an aqueous solvent is used, there is little environmental pollution caused by volatilization of the organic solvent in the process, and this is a so-called environmentally friendly film forming method.
(4) Uniform film formation is possible even for substrates that are difficult to form using a vacuum, such as substrates with complex surface shapes and inner walls of thin tubes.
It has the features such as. In these film forming methods, the reaction solution and the substrate are brought into contact with each other by immersing the substrate in the reaction solution, and a film is formed on the surface of the substrate.
[0011]
These film formation methods are based on an oxide formation reaction by hydrolysis of hexafluorometal acid (or salt), and in order to promote hydrolysis, boric acid, aluminum chloride, aluminum metal, etc. are added to form a film. It is done.
[0012]
FIG. 6 is a cross-sectional view showing an example of the structure of a reaction apparatus that performs a conventional method for forming a film on a substrate. A reaction liquid 2 as described in the above document is filled in a reaction vessel (reaction vessel) 1, and a substrate 3 having an arbitrary shape for forming a film is immersed in the reaction liquid. A temperature controller 14 is disposed outside the reaction tank 1 for the purpose of keeping the reaction temperature constant and keeping the reaction rate constant, or heating the entire reaction solution to increase the reaction rate. . The temperature controller 14 is, for example, a heater, and a warm bath or a water bath device is also used instead of the temperature controller.
[0013]
The temperature control described in these documents is to heat (warm) the entire reaction solution for the purpose of accelerating the film formation rate, and the heating control temperature is a temperature range of room temperature or higher. Japanese Patent Application Laid-Open No. 64-28376 discloses cooling the entire reaction solution instead of heating for the purpose of controlling the composition of the coating film.
[0014]
[Problems to be solved by the invention]
In the film forming method described in the above-mentioned document, the obtained oxide film is also formed on the wall surface of the reaction vessel in addition to the substrate surface. In addition, fine particles of these oxides are simultaneously generated in the reaction liquid other than the substrate surface. The reason is that if the reaction solution conditions (composition, concentration, temperature, etc.) in the reaction vessel are the same, the oxide formation reaction proceeds simultaneously in the entire reaction solution.
[0015]
Part of the oxide film formed on the wall of the reaction vessel and peeled off from it, and oxide fine particles generated in the reaction liquid diffuse in the reaction liquid due to convection and vibration of the reaction liquid, In some cases, it may cause inconvenience in forming a uniform film on the substrate due to adhesion. In addition, the unnecessary fine particles generated during the formation of the film further serve as reaction nuclei, which further promotes the generation of oxide fine particles, resulting in a vicious circle.
[0016]
As described above, a film is formed on a portion other than the target substrate surface, or unnecessary fine particles that are not involved in the film formation are generated. As a result, an oxide film is formed on the substrate surface, which is the original purpose. The efficiency tended to decrease.
[0017]
The object of the present invention is to reduce the reaction of forming unnecessary fine particles that are not directly involved in the film formation in the reaction solution, and to suppress the formation of a film on the surface other than the surface of the substrate, thereby participating in the film formation on the surface of the substrate. It is an object to provide a film forming method that preferentially promotes only the film.
[0018]
[Means for Solving the Problems]
Among the methods for forming a thin film proposed in the above-mentioned document, there is one described about temperature control of the entire reaction solution as shown in FIG. However, in these documents, neither the control of the temperature of the base material that is the object of film formation nor the temperature control of the temperature of the reaction liquid limited to the vicinity of the base material is considered or considered at all. The effect of temperature control is not clear.
[0019]
In the liquid phase film forming method of the present invention, a base material maintained at a temperature higher than the temperature of the reaction liquid is immersed in a reaction liquid containing a compound of the film material, and the base material and the reaction liquid are mixed. A step of causing the chemical reaction of the compound to selectively proceed on and near the surface of the substrate to deposit the coating material on the surface of the substrate to form a coating.
[0020]
In the embodiment of the present invention, in order to preferentially promote only the reaction involved in the film formation on the surface of the substrate, the substrate and the reaction vessel (reaction liquid) are not directly related to the portion directly related to the film formation. By selectively performing individual temperature control on the part, the temperature of the substrate surface and the vicinity thereof is controlled to be higher than the temperature of the other reaction liquid.
[0021]
【Example】
Next, some examples of the film forming method according to the present invention will be described with reference to FIGS.
[0022]
FIG. 1 is a sectional view showing the structure of a reaction apparatus for carrying out a method for forming a film on a substrate according to an embodiment of the present invention. The reaction vessel (reaction vessel) 1 is filled with, for example, a reaction solution 2 containing a compound of a film material as described in the above-mentioned literature, and an arbitrary shape for forming a film in the reaction solution. A part of the substrate 3 is immersed. A temperature adjuster (or temperature adjusting material) 4 for controlling the temperature of the reaction solution is disposed outside the reaction tank 1. The temperature controller 4 is a cooler (cooler), for example, and cools the reaction tank 1 to lower the temperature of the reaction solution 2. In place of the cooler, a water bath device or a cooling medium may be arranged. Furthermore, another temperature controller 5 is disposed on the surface of the base 3 that is not in contact with the reaction solution 2. This temperature controller 5 is, for example, a heater, and is provided for the purpose of heating the base material 3 to adjust it to a desired temperature and promoting film formation on the surface of the base material in contact with the reaction solution 2. As the temperature controller 5, a method of contacting a heating medium such as a hot water bath or a method of irradiating energy such as light or radio waves can be used instead of the heater.
[0023]
In the apparatus of FIG. 1, first, the reaction solution 2 and the reaction tank 1 are cooled to a temperature lower than the temperature condition in which the chemical reaction of the reaction solution works well with the temperature controller 4, and the reaction solution 2 is kept at a low temperature. Thereby, the production | generation of the oxide particle in a reaction liquid and the film formation rate to the reaction tank inner wall can be kept quite low.
[0024]
Next, the surface of the substrate 3 on which a film is to be formed is immersed in the reaction solution 2 and brought into contact therewith. And the base material 3 is heated with the temperature controller 5 arrange | positioned on the opposite side to the side which is contacting the reaction liquid, the temperature of the base material 3 is raised, and it becomes higher than the temperature of the reaction liquid 2 Control the temperature. The heat applied to the substrate 3 is transferred to the reaction solution 2 near the substrate in contact with it, and the temperature of the reaction solution 2 near the substrate becomes higher than the temperature of the surrounding reaction solution 2. The heating period (heating start time) for the base material 3 may be preheated to a predetermined temperature before the base material 3 is brought into contact with the reaction solution 2, or may be in the middle of contact, or completely. It may be started after the contact is completed, or a combination thereof may be used, and the best heating period may be appropriately selected depending on the shape and material of the base material 3 or desired coating conditions.
[0025]
The heat to be transmitted to the base material 3 only needs to be such that the temperature of the surface of the base material in contact with the reaction liquid 2 is higher than the temperature of the reaction liquid 2 cooled first, and the base material has become higher than the ambient temperature. The film formation reaction of the reaction solution 2 is promoted at the surface of 3 and the vicinity thereof to increase the film formation rate. At the same time, the inner wall of the reaction tank 1 that is not directly involved in film formation and the reaction solution 2 far from the surface of the base material 3 are cooled to a low temperature, so that unnecessary film formation and fine particle formation are unlikely to occur. For this reason, the film formation reaction proceeds efficiently only on the necessary substrate surface.
[0026]
FIG. 2 is a sectional view showing the structure of a reaction apparatus for carrying out a method for forming a film on a substrate according to another embodiment of the present invention. About the reaction tank 1, the reaction liquid 2, and the temperature controller 4, it is the same as that of the Example of FIG. The base material 31 has a cavity inside, and in the illustrated case, has a cross-shaped cavity, and another temperature controller 6 is disposed inside and outside the cavity. The temperature controller 6 is, for example, a small heater that can be inserted into a cavity. The substrate 31 is heated from the inside to be adjusted to a desired temperature, and is formed on the substrate outer surface in contact with the reaction solution 2. It is provided for the purpose of promoting the film. The temperature controller 5 can be heated by filling a cavity with hot water or another heating medium instead of the heater.
[0027]
FIG. 3 is a sectional view showing the structure of a reaction apparatus for carrying out a method for forming a film on a substrate according to another embodiment of the present invention. About the reaction tank 1, the reaction liquid 2, and the temperature controller 4, it is the same as that of the Example of FIG. The base material 32 has a tubular shape having a hollow with a circular cross section inside, and is heated by flowing hot water or other heating medium 7 into and out of the hollow. Instead of the heating medium 7, a heater that can be inserted into the cavity can be arranged. The tubular substrate 32 is heated from the inside by the heating medium 7 to adjust the temperature to a desired temperature, and film formation on the outer surface of the substrate in contact with the reaction solution 2 is promoted.
[0028]
FIG. 4 is a sectional view showing the structure of a reactor for carrying out a method for forming a film on a substrate according to still another embodiment of the present invention. FIG. 4B is a cross-sectional view taken along line II ′ of FIG. In this embodiment, the base material 33 has a tube shape having a hollow section with a circular cross section as in the embodiment of FIG. The difference from the example of FIG. 3 is that a film is formed on the inner wall of the base material 33 on the cavity side. Accordingly, the reaction liquid 2 is caused to flow in the cavity. The base material 33 is fixed to the reaction vessel 10 by the fixing member 11. The reaction tank 10 is filled with warm water or another heating medium 8. The heating medium 8 and a heater (not shown) may be used in combination. With the heating medium 8, the tubular substrate 33 is heated from the outside to be adjusted to a desired temperature, and film formation on the inner surface of the substrate in contact with the reaction solution 2 is promoted.
[0029]
On the other hand, the reaction liquid 2 is stored in a temperature control tank 9 provided separately from the reaction tank 10. The temperature control tank 9 is a cooler (cooler), for example, and cools the reaction liquid 2 to a low temperature. The reaction liquid 2 that has been cooled down flows into the cavity of the base material 33 through the communication pipe 12. The reaction solution 2 that has flowed in comes into contact with the inner wall of the heated base material 33 to form a coating immediately. Excess reaction liquid 2 is discharged to the outside from the discharge pipe 13 or circulates back to the temperature control tank 9.
[0030]
FIG. 5 is a graph (black circle) measuring the relationship between the film formation time (horizontal axis) and the film thickness (vertical axis) when a film is actually formed on the surface of the substrate by the film forming method of the embodiment of the present invention. ). For comparison, a curve (plotted by □) in the case of film formation according to the conventional technique of FIG. 6 is also shown.
[0031]
To a supersaturated aqueous solution of titanium oxide prepared by adding 0.3 mol / liter of H ₃ BO ₃ as an additive for promoting hydrolysis to 0.1 mol / liter of (NH ₄ ) ₂ TiF ₆ (ammonium titanium fluoride) A titanium oxide film was formed by contacting the substrate. In the examples of the present invention, the substrate was heated to 60 ° C., and the 26 ml of the reaction solution was cooled to 0 ° C. to increase the temperature on the substrate side. In the comparative conventional method, no heat treatment was performed on the substrate side, and the 26 ml of the reaction solution was heated to 60 ° C. (the substrate was also close to 60 ° C.).
[0032]
As is apparent from the graph of FIG. 5, in the film forming method according to the embodiment of the present invention, the film thickness increases from the beginning in proportion to the film forming time, and after a lapse of 20 hours, the slope becomes somewhat gentle, but thereafter The increasing trend continues. On the other hand, in the conventional method, although a gradual increase in the film thickness was observed until 7 to 8 hours, the increase in the film thickness was hardly observed after that. In the embodiment of the present invention, unnecessary film formation on the inner wall of the reaction vessel and formation of fine particles in the reaction solution are effectively suppressed, and the film formation reaction is preferentially performed only on the substrate surface. This is probably because it was done.
[0033]
The method for forming a film in the liquid phase described above is not limited to the hydrolysis reaction as long as the reaction is accelerated at a high temperature. Formation of optical thin films, optical interference filters, antifouling films, or antifogging films on glass substrates, film formation on solar cells, dielectric films, capacitors, piezoelectric elements, various display elements, coatings on display devices, etc. Can be used for formation.
[0034]
As mentioned above, although this invention was demonstrated along the Example, this invention is not restrict | limited to these. It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.
[0035]
【The invention's effect】
As described above, according to the present invention, only the reaction involved in the film formation on the substrate surface is promoted preferentially. In the base material and the reaction vessel (reaction liquid), individual temperature control is selectively performed at a portion directly related to film formation and a portion not directly related to film formation. By controlling the temperature of the substrate surface and its vicinity to be higher than the temperature of the other reaction solutions, the inner wall of the reaction tank that is not directly related to film formation and the reaction solution far from the substrate surface are at a low temperature. Keep on. Since unnecessary film formation and fine particle formation are unlikely to occur, the film formation reaction proceeds efficiently only on the necessary substrate surface. Furthermore, since the generation of fine particles in the reaction liquid is reduced, it is possible to suppress an adverse effect on the formed film on the substrate due to the diffused fine particles.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an apparatus for carrying out a liquid phase film forming method according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of an apparatus for carrying out a liquid phase film forming method according to another embodiment of the present invention.
FIG. 3 is a cross-sectional view of an apparatus for carrying out a liquid phase film forming method according to another embodiment of the present invention.
FIG. 4 is a cross-sectional view of an apparatus for carrying out a liquid phase film forming method according to still another embodiment of the present invention.
FIG. 5 is a graph showing the relationship between the film formation time and the film thickness of a film forming method according to an embodiment of the present invention compared to the case of a conventional film forming method.
FIG. 6 is a cross-sectional view of an apparatus for carrying out a liquid phase film forming method according to the prior art.
[Explanation of symbols]
1 reaction tank (reaction vessel)
2

Reaction solution

3, 31, 32, 33 Base material (film formation target)
4 Temperature Controller 5 Temperature Controller 6

Temperature Controller

7, 8 Heating Medium 9 Temperature Controller 10 Reaction Tank 11 Fixing Member 12 Connection Pipe 13 Discharge Pipe 14 Temperature Controller

Claims

A reaction liquid containing a coating material, the step of preparing a reaction liquid for advancing a chemical reaction that promotes the reaction by heating ; and
Cooling the reaction solution to a temperature condition lower than a temperature condition at which a chemical reaction of the reaction solution works well;
Immersing a substrate in the reaction solution, and contacting the substrate and the reaction solution;
By heating the substrate in a heating unit and heated to a temperature higher than the temperature of the reaction solution, the substrate is allowed to proceed selectively the chemical reaction in the reaction solution of the surface and its vicinity of the substrate forming a coating film causing precipitation on the surface,
A method for forming a film in a liquid phase.

Furthermore, the film formation method in the liquid phase of Claim 1 which has the process of heating the said base material before immersing the said base material in the said reaction liquid.

The method for forming a film in a liquid phase according to claim 1 or 2 , wherein the surface of the substrate is in contact with the reaction solution, and a heating medium is brought into contact with a part of the surface of the substrate to heat.

The method for forming a film in a liquid phase according to claim 1 or 2 , wherein the surface of the substrate is in contact with the reaction solution, has a cavity inside the substrate, and a heating medium is disposed in the cavity to heat. .

Has a cavity inside the base, the inner wall of the cavity is in contact with the reaction solution, according to claim 1 or 2 is heated by irradiating an energy or contacting the heating medium to the outer surface of the base material A method for forming a film in the liquid phase.

The method for forming a film in a liquid phase according to any one of claims 1 to 5 , wherein the reaction solution is an aqueous solution, and the chemical reaction is a reaction including hydrolysis.

The _{_{coating, TiO 2, ZrO 2, HfO}} 2, SiO 2, and the film forming method in the liquid phase according to any one of claims 1 to 6 including any of these combinations.