JP2019204687A

JP2019204687A - Manufacturing method of insulation film of aggregate of flat powders in which flat surfaces of insulation flat powders with shape of bottom are overlapped on bottom of container

Info

Publication number: JP2019204687A
Application number: JP2018099230A
Authority: JP
Inventors: 小林　博; Hiroshi Kobayashi; 博小林
Original assignee: Individual
Current assignee: Individual
Priority date: 2018-05-23
Filing date: 2018-05-23
Publication date: 2019-11-28
Anticipated expiration: 2038-05-23
Also published as: JP7023035B2

Abstract

To provide a technology for manufacturing an insulation film satisfying requirements, 1. capable of manufacturing an insulation film at low cost, 2. capable of changing the surface area and shape of the insulation film, 3. capable of forming an insulation surface on a surface of the conductor by crimp, 4. capable of forming an insulation layer with a thickness of around 3 μm, and 5. having an insulation resistance of 10Ω.SOLUTION: There is provided a method for manufacturing an insulation film on a whole bottom of a container, in which flat surfaces of insulation flat powder 2 are arranged to overlap with each other in an alcohol dispersion of a metallic compound that precipitates aluminum oxide by thermal decomposition, the metal compound is thermal decomposed, an aggregation of aluminum oxide fine particles 1 is deposited in a gap between flat surfaces and on the flat surface, then compression stress is applied to the laminated flat surface, and aluminum oxide fine particles are conjugated by frictional heat. Thereby the insulation film in which flat surfaces are conjugated each other is manufactured at the bottom of the container.SELECTED DRAWING: Figure 1

Description

本発明は、容器の底面全体に、絶縁性扁平粉の扁平面同士が重なり合うように配列し、扁平面同士の間隙に析出した酸化アルミニウム微粒子同士を摩擦熱で接合することで扁平面同士を接合し、容器の底面に絶縁膜を製造する製造方法に係わる。この製造方法に依れば、１０^１８Ωに及ぶ絶縁抵抗の絶縁膜の製造が可能で、また、絶縁膜の表面積と形状とが容器の底面形状に応じて変えられる。さらに、部品や基材の導体に、絶縁膜を圧着によって絶縁層を形成する。なお、扁平粉をフレーク粉、鱗片粉、円板粉と呼ぶこともある。 In the present invention, the flat surfaces of the insulating flat powder are arranged on the entire bottom surface of the container so that the flat surfaces overlap each other, and the aluminum oxide fine particles precipitated in the gaps between the flat surfaces are bonded to each other by frictional heat. And a manufacturing method for manufacturing an insulating film on the bottom surface of the container. According to this manufacturing method, an insulating film having an insulation resistance of 10 ¹⁸ Ω can be manufactured, and the surface area and shape of the insulating film can be changed according to the bottom shape of the container. Furthermore, an insulating layer is formed on the conductor of the component or the base material by crimping an insulating film. In addition, flat powder may be called flake powder, scale powder, and disk powder.

導体への絶縁層の形成には様々な方法がある。
例えば、特許文献１に、ゾル−ゲル法に依るアルミナ絶縁膜の形成方法が記載されている。すなわち、アルミニウム化合物を含むゾルに、解膠剤を添加したアルミナ前駆体溶液を、電気泳動電着法によって基材上にアルミナ絶縁膜を形成する。つまり、第一に、アルミニウム化合物にエタノールなどの有機溶媒を添加し、更に、解膠剤として塩酸などを添加し撹拌してゾルを調製する。次に、ゾルを恒温槽に配置し、ゲル化しない４０−６０℃の温度範囲で１−３時間撹拌してアルミナ前駆体溶液を調製する。第三に、アルミナ前駆体溶液中で起きている加水分解・縮合反応を平衡状態にするため、アルミナ前駆体溶液を恒温槽で４０−６０℃の温度範囲で１２時間以上保持する。第四に、被電着材料として、例えばシリコン基板の表面に白金膜を形成した電極を用意し、また、対向電極として、例えばシリコン基板の表面に白金膜を形成した電極を用意する。２枚の電極が形成されたシリコン基板をアルミナ前駆体溶液中にそれぞれ浸漬し、さらに、電荷の移動量が設定量に達するまで、両基板の電極間に直流電圧を印加し、正に帯電したアルミナ前駆体が陰極として使用したシリコン基板の電極上に析出させる。第五に、アルミナ前駆体が析出したシリコン基板をプレートの上に設置し、大気雰囲気中、１００℃以上、３分以上の条件で加熱乾燥する。第六に、乾燥したシリコン基板の白金電極に析出したアルミナ前駆体を、ガスを酸素とした雰囲気中、昇温速度１−２０℃／秒で室温から７００℃まで昇温し、１分以上の間保持し、アルミナ前駆体を結晶化して絶縁膜を形成する。こうして白金電極の表面にアルミナの絶縁層が形成される。このように、絶縁層を形成する処理工程が複雑多岐にわたり、さらに、７００℃の熱処理が必要なため、本絶縁層の形成方法は、汎用的な絶縁層を形成する方法ではない。 There are various methods for forming an insulating layer on a conductor.
For example, Patent Document 1 describes a method for forming an alumina insulating film by a sol-gel method. That is, an alumina insulating film is formed on a substrate by an electrophoretic electrodeposition method using an alumina precursor solution in which a peptizer is added to a sol containing an aluminum compound. That is, first, an organic solvent such as ethanol is added to the aluminum compound, and hydrochloric acid or the like is further added as a peptizer and stirred to prepare a sol. Next, the sol is placed in a thermostatic bath and stirred for 1 to 3 hours in a temperature range of 40 to 60 ° C. where no gelation occurs to prepare an alumina precursor solution. Third, in order to bring the hydrolysis / condensation reaction occurring in the alumina precursor solution into an equilibrium state, the alumina precursor solution is held in a thermostatic bath at a temperature range of 40-60 ° C. for 12 hours or more. Fourth, for example, an electrode having a platinum film formed on the surface of a silicon substrate is prepared as an electrodeposition material, and an electrode having a platinum film formed on the surface of a silicon substrate is prepared as the counter electrode. Each silicon substrate on which two electrodes are formed is immersed in an alumina precursor solution, and further, a DC voltage is applied between the electrodes of both substrates until the amount of charge movement reaches a set amount, and the substrate is positively charged. An alumina precursor is deposited on the electrode of the silicon substrate used as the cathode. Fifth, the silicon substrate on which the alumina precursor is deposited is placed on a plate, and is heated and dried in an air atmosphere at 100 ° C. or higher and for 3 minutes or longer. Sixth, the alumina precursor deposited on the platinum electrode of the dried silicon substrate was heated from room temperature to 700 ° C. at a temperature rising rate of 1-20 ° C./second in an atmosphere containing oxygen as a gas for 1 minute or more. The insulating film is formed by crystallizing the alumina precursor. Thus, an alumina insulating layer is formed on the surface of the platinum electrode. As described above, since the processing steps for forming the insulating layer are complicated and diverse, and heat treatment at 700 ° C. is required, the method for forming this insulating layer is not a method for forming a general-purpose insulating layer.

特許文献２には、プラズマディスプレイ装置において、前面板の表示電極を被覆してプラズマ放電を維持するベタ膜上の絶縁膜と、背面板に形成されたアドレス電極を被覆する絶縁膜との双方の絶縁層の形成に係わる記載がある。すなわち、熱重合開始剤と熱硬化性成分とガラス粒子とからなる絶縁ペーストを基板に塗布し、塗布膜を加熱して硬化率が３０−９５％になるように半硬化処理を行い、さらに過熱して絶縁層を形成する。つまり、塗布膜を９５℃に加熱し、３０分間放置した後に２５℃に冷却し、半硬化膜を作成する。さらに、半硬化膜を３８０℃で１０分間過熱し、有機成分を加熱除去した後に、６００℃で１０分間過熱し、ガラス粒子を焼結して絶縁層を形成する。つまり、基板上に電極が形成されているため、基板の凸部（電極形成部）の半硬化膜の焼成収縮率が、基板の凹部（電極非形成部）の半硬化膜の焼成収縮率を大きく上回ることで、全体として平滑性の高い絶縁膜を得ることができる。このため、半硬化膜を作成する必要がある。本絶縁膜が比較的大きな面積を持つため、平滑性に優れた絶縁膜を形成するには、前記のような複雑な熱処理が必要になる。また、熱重合開始剤と熱硬化性成分とからなる薬品は特殊な工業用薬品である。このように絶縁膜の形成方法は、特殊な薬品を用い、複雑で多岐にわたる熱処理を施し、さらに、６００℃の熱処理が必要になる。このため、本絶縁層の形成方法も、汎用的な絶縁層を形成する方法ではない。 In Patent Document 2, in the plasma display device, both of the insulating film on the solid film that covers the display electrode of the front plate and maintains the plasma discharge, and the insulating film that covers the address electrode formed on the back plate are disclosed. There is a description relating to the formation of an insulating layer. That is, an insulating paste composed of a thermal polymerization initiator, a thermosetting component, and glass particles is applied to a substrate, a coating film is heated, a semi-curing treatment is performed so that the curing rate is 30 to 95%, and further overheating is performed. Thus, an insulating layer is formed. That is, the coating film is heated to 95 ° C., left for 30 minutes, and then cooled to 25 ° C. to form a semi-cured film. Further, the semi-cured film is heated at 380 ° C. for 10 minutes to remove organic components by heating, and then heated at 600 ° C. for 10 minutes to sinter the glass particles to form an insulating layer. That is, since the electrode is formed on the substrate, the baking shrinkage rate of the semi-cured film on the convex portion (electrode forming portion) of the substrate is equal to the baking shrinkage rate of the semi-cured film on the concave portion (electrode non-forming portion) of the substrate. By exceeding greatly, an insulating film with high smoothness as a whole can be obtained. For this reason, it is necessary to create a semi-cured film. Since this insulating film has a relatively large area, the complex heat treatment as described above is required to form an insulating film with excellent smoothness. Moreover, the chemical | medical agent which consists of a thermopolymerization initiator and a thermosetting component is a special industrial chemical | drug | medicine. As described above, the method for forming the insulating film requires a complicated and diverse heat treatment using a special chemical, and further requires a heat treatment at 600 ° C. For this reason, the method for forming this insulating layer is not a method for forming a general-purpose insulating layer.

特許文献３には、高密度化された半導体装置に必要な低誘電率層間絶縁膜の形成方法に関する記載がある。耐吸湿性、及び、耐熱性が良い低誘電率層間絶縁膜の具体的な物質として、Ｓｉ含有アルキル化合物ではトリメチルシラン（ＴＭＳ）と、Ｓｉ含有アルコキシ化合物ではテトラエチルオルソシリケート（ＴＥＯＳ）が挙げられている。しかし、ＴＥＯＳの電気伝導度は３×１０^−６Ｓ／ｍであり、電気伝導度が５９×１０^６Ｓ／ｍである銅の５×１０^−１３に過ぎず、電気絶縁性が十分でない。このため、電子回路が長時間稼働されると、絶縁層に流れる漏れ電流によって絶縁層が発熱し、導体に配置された電子部品が熱劣化する恐れがある。 Patent Document 3 describes a method for forming a low dielectric constant interlayer insulating film necessary for a high-density semiconductor device. Specific examples of the low dielectric constant interlayer insulating film having good moisture absorption resistance and heat resistance include trimethylsilane (TMS) for Si-containing alkyl compounds and tetraethylorthosilicate (TEOS) for Si-containing alkoxy compounds. Yes. However, the electrical conductivity of TEOS is 3 × 10 ⁻⁶ S / m, which is only 5 × 10 ^{−13 of} copper having an electrical conductivity of 59 × 10 ⁶ S / m, and the electrical insulation is not sufficient. For this reason, when the electronic circuit is operated for a long time, the insulating layer generates heat due to the leakage current flowing through the insulating layer, and the electronic component disposed on the conductor may be thermally deteriorated.

特開２０１４−１７５３８９号公報JP 2014-175389 A 国際公開ＷＯ２０１４／６１５９０号公報International publication WO2014 / 61590 特開２０００−３３２０１０号公報JP 2000-332010 A

次の５つの要件を満たす絶縁膜は汎用的な絶縁膜になる。本発明の課題は、これら５つの要件を満たす絶縁膜を製造する方法を実現することにある。
第一に、安価な材料を用い、極めて簡単な処理で絶縁膜が形成できる。これによって、安価な費用で絶縁膜が製造できる。
第二に、製造する絶縁膜の表面積と形状との各々が自在に変えられる。これによって、用途に応じた表面積と形状とからなる絶縁層が導体に形成できる。
第三に、絶縁膜の圧着によって導体の表面に絶縁層が形成できる。従って、熱処理を伴わずに導体に絶縁層が形成でき、耐熱性の低い部品や基材の導体に絶縁層が形成できる。
第四に、少量の絶縁材料を用いて、３μｍ前後の厚みの絶縁層が形成できる。これによって、安価な費用で極めて大きな絶縁抵抗からなる絶縁膜が形成できる。
第五に、絶縁抵抗が１０^１８Ωに及ぶ値を持つ。従って、絶縁層に漏れ電流が流れず、絶縁層が発熱しないため、導体に接合された部品は、長期にわたって熱劣化しない。 An insulating film that satisfies the following five requirements is a general-purpose insulating film. An object of the present invention is to realize a method of manufacturing an insulating film that satisfies these five requirements.
First, an insulating film can be formed by an extremely simple process using an inexpensive material. Thereby, an insulating film can be manufactured at low cost.
Second, the surface area and shape of the insulating film to be manufactured can be freely changed. Thereby, an insulating layer having a surface area and a shape corresponding to the application can be formed on the conductor.
Third, an insulating layer can be formed on the surface of the conductor by pressure bonding of the insulating film. Therefore, an insulating layer can be formed on a conductor without heat treatment, and an insulating layer can be formed on a conductor of a component or substrate having low heat resistance.
Fourth, an insulating layer having a thickness of about 3 μm can be formed using a small amount of insulating material. As a result, an insulating film having an extremely large insulation resistance can be formed at a low cost.
Fifth, the insulation resistance has a value ranging from 10 ¹⁸ Ω. Accordingly, no leakage current flows through the insulating layer, and the insulating layer does not generate heat, so that the component joined to the conductor is not thermally deteriorated over a long period of time.

本発明の絶縁膜の製造方法は、酸化アルミニウムを熱分解で析出する金属化合物を、アルコールに分散してアルコール分散液を作成する第一の工程と、前記アルコール分散液に絶縁性扁平粉の集まりを混合して混合物を作成する第二の工程と、前記混合物を混合機内で回転及び揺動させる第三の工程と、前記混合物をホモジナイザー装置で処理する第四の工程と、前記混合物を底が浅い容器に充填する第五の工程と、前記容器に左右、前後、上下の３方向の振動を繰り返し加える第六の工程と、前記容器を前記金属化合物が熱分解する温度に昇温する第七の工程と、前記容器の底面に形成された絶縁膜に圧縮応力を加える第八の工程からなるこれら８つの処理を連続して実施することによって、前記容器の底面に、該底面の形状からなる絶縁膜が製造される、絶縁膜の製造方法である。 The method for producing an insulating film of the present invention includes a first step in which a metal compound that precipitates aluminum oxide by pyrolysis is dispersed in alcohol to create an alcohol dispersion, and a collection of insulating flat powders in the alcohol dispersion. A second step of mixing the mixture, a third step of rotating and swinging the mixture in a mixer, a fourth step of treating the mixture with a homogenizer device, and a bottom of the mixture. A fifth step of filling a shallow container; a sixth step of repeatedly applying left, right, front, back, top and bottom vibrations to the container; and seventh raising the temperature of the container to a temperature at which the metal compound is thermally decomposed. And the eight processes including the eighth step of applying compressive stress to the insulating film formed on the bottom surface of the container are continuously performed, thereby forming the bottom surface of the container in the shape of the bottom surface. Insulation There is produced, it is a manufacturing method of the insulating film.

つまり、本製造方法に依れば、極めて簡単な８つの処理を連続して実施すると、安価な製造費で容器の底面に絶縁膜が形成される。この絶縁膜の表面積と形状とは、容器の底面形状になる。このため、絶縁膜の用途に応じて、製造する絶縁膜の表面積と形状とが自在に変えられる。
すなわち、本製造方法が次の４つの特徴を持つことによって、製造された絶縁膜に画期的な作用効果がもたらされる。
第一に、混合物を充填する容器の形状に制約がない。このため、製造される絶縁膜の表面積は、混合物を充填する容器の形状に応じて変わる。例えば、１ｍｍ^２のスポット的な微小膜から１００ｍｍ^２を超える細長い短冊状の絶縁膜に至るまで、製造できる絶縁膜の形状の制約がない。
第二に、金属化合物のアルコール分散液の粘度はアルコールの粘度に近く、また、固体の扁平粉の少量をアルコール分散液に混合しても、混合物の粘度が増大しない。従って、混合物を容器に充填し、容器に３方向の振動を加えると、扁平粉の扁平面が重力方向に向いてアルコール分散液中を移動し、容器の底面全体に分散するとともに、扁平面同士が重なり合う。例えば、少量の扁平粉を、扁平面同士が３重に重なり合うように、容器の底面に扁平粉を配列させると、酸化アルミニウム微粒子の集まりが４層を形成し、扁平面の層が３層を形成し、両者が交互に重なり合って絶縁膜を形成する。この絶縁膜が形成する絶縁抵抗は、扁平面の同一層における隣接する扁平粉の間隙を埋める僅かな量の酸化アルミニウム微粒子の集まりの存在を無視すると、酸化アルミニウム微粒子の集まりからなる４つの絶縁抵抗層と、絶縁性扁平粉からなる３つの絶縁抵抗層とが、順番に重なり合って並列接続して絶縁抵抗を構成する。従って、電気抵抗率が１０^１４Ωｃｍの扁平粉を用いると、厚みが３μｍで幅が１ｃｍで長さが１０ｃｍの絶縁層では、３×１０^１８Ωの絶縁抵抗になる。つまり、電気抵抗率が大きい２種類の絶縁材料からなる絶縁層の各々が、１μｍより薄い厚みで積み重なり合って絶縁層を形成し、これらの絶縁層が並列接続して絶縁抵抗を構成するため、絶縁膜の絶縁抵抗は極めて大きな値になる。
第三に、混合物を充填する容器の形状に制約がない。このため、絶縁膜の形状は、円、楕円、多角形に限らず、用途に応じて様々な形状の絶縁膜が製造できる。
第四に、金属化合物が熱分解すると、扁平面同士の間隙と絶縁膜の表面に、４０−６０ｎｍの大きさの粒状の酸化アルミニウム微粒子の集まりが析出する。次に、容器の底面に形成された絶縁膜の表面に圧縮応力を加えると、酸化アルミニウムはモース硬度が９の極めて硬い物質であり、酸化アルミニウム微粒子同士が互いに接触する僅かな面積からなる接触部位に、過大な摩擦熱が集中して発生し、酸化アルミニウム微粒子が破壊されずに、摩擦熱によって酸化アルミニウム微粒子同士が接触部位で接合し、一定の機械的強度を持つ絶縁膜が容器の底面に形成される。従って、製造された絶縁膜の表面に、４０−６０ｎｍの大きさの粒状の酸化アルミニウム微粒子の集まりが存在する。この酸化アルミニウム微粒子の集まりは、絶縁膜を部品や基材の導体に圧着する手段になる。このため、部品や基材の導体に絶縁膜を形成する際の熱処理が一切不要になり、耐熱性が低い部品や基材の導体にも絶縁膜が形成できる。
ここで、本製造方法を見出すに至る過程を説明する。絶縁性扁平粉は、長径と短径との平均値と厚さとの比率であるアスペクト比が大きい扁平面を有する。さらに、扁平面の大きさと厚みとにバラツキがある。このような扁平粉の集まりにおいては、扁平面同士が容易に重なり合う。扁平面同士が重なり合った扁平粉を接合した絶縁膜は、扁平面同士が重なり合った部位で破壊する。従って、扁平面同士が重なり合った部位を、分離させることが必要になる。いっぽう、大気中で扁平面の重なり合った部位を分離しようとすると、重なり合った部位に摩擦力が発生するため、分離は容易でない。しかしながら、粘度が低い液体に扁平粉の集まりを混合し、この液体内に衝撃を発生させると、衝撃が扁平面同士の重なり合った部位に伝わり、重なり合った部位が容易に分離する。このため、粘度の低い液体中で、扁平粉の集まりを処理することが必須になる。
さらに、扁平面同士で扁平粉が接合できれば、少量の扁平粉で広い表面積を持つ絶縁膜が形成できる。さらに、少量の扁平粉の集まりを容器の底面全体に分散させ、扁平面同士で重なり合うように配列させると、厚みが極めて薄い絶縁膜が容器の底面に形成され、この絶縁膜は大きな絶縁抵抗を持つ。例えば、扁平面同士が３重に重なり合うように配列させると、３μｍ前後の厚みの絶縁膜が形成でき、絶縁抵抗は絶縁膜の断面積に反比例するため、絶縁抵抗が極めて大きい。従って、扁平粉の集まりを容器の底面全体に分散させ、扁平粉の扁平面同士が重なり合うように配列させる処理が必要になる。
いっぽう、扁平面が一定の面積を持つため、扁平面同士の接合で形成された絶縁膜は、接合面が一定の面積を持つため、一定の機械的強度を持つ。従って、扁平粉の扁平面同士が重なり合うように、扁平粉を配列させる処理が必要になる。ところで、容器に充填された液体中で、扁平粉の集まりに３方向の振動を加えると、扁平面が重力方向に向いて液体中を移動し、重力方向に向いた扁平面の配列が繰り返され、振動を停止すると、扁平面同士が液体を介して重なり合う。このため、扁平粉の集まりを液体に混合し、この混合物を容器に充填し、容器に振動を加える処理が必要になる。
さらに、絶縁性扁平粉は、扁平面の長径と短径との平均値と厚みとにバラツキがある。こうした扁平粉を原料に用い、絶縁膜を製造する。しかしながら、扁平面同士を接合する物質が、扁平面より２桁以上小さい数十ナノの微粒子であれば、微粒子の集まりが扁平面に確実に析出する。また、面積が広い扁平面に優先して微粒子が析出する。さらに、扁平面の大きさにバラツキがあっても、扁平面が微粒子の大きさより２桁以上大きいため、扁平面に微粒子が確実に析出する。さらに、微粒子が粒状であれば、微粒子の集まりが析出する際に、微粒子同士が極狭い接触面積からなる接触部位で接触する。さらに、微粒子の硬度が高ければ、微粒子の集まりに圧縮応力を加えると、微粒子が破壊することなく、微粒子同士の接触部位に摩擦熱が集中して発生し、この摩擦熱で微粒子同士接合する。扁平面同士を接合する手段は、扁平面に硬度の高い粒状の微粒子の集まりを析出させ、微粒子の集まりに圧縮応力を加え、微粒子同士を摩擦熱で接合することを介して、扁平面同士を接合させる手段が有効になる。こうした微粒子を構成する物質として、１０^１４Ωｃｍの高い抵抗率と、モース硬度が９である高い硬度と、摩擦熱で変質しない１５００℃を超える高い耐熱性を持つ、酸化アルミニウム（アルミナとも言う）がある。
従って、絶縁膜を製造する製造方法は、第一に、酸化アルミニウム微粒子の原料を液相化し、この液体に少量の扁平粉を混合し混合物を作成する。第二に、扁平面同士が重なり合った部位を液体中で分離する。この結果、全ての扁平粉は液体と接する。第三に、混合物を容器に充填する。第四に、少量の扁平粉が容器の底面の全体にわたって分散し、扁平面同士が互いに重なり合う処理を行う。このため、容器に３方向の振動を繰り返し加え、容器の底面の全体に扁平粉を分散させ、扁平面同士が重なり合う処理を行う。第五に、容器を昇温し、酸化アルミニウム微粒子の原料を熱分解し、酸化アルミニウム微粒子の集まりを析出させる。つまり、熱分解によって酸化アルミニウムを析出させる手段が、最も簡便である。これによって、扁平粉の扁平面同士の間隙と絶縁膜の表面とに、４０−６０ｎｍの大きさの粒状の酸化アルミニウム微粒子の集まりが析出する。最後に、容器の底面に形成された絶縁膜の表面に圧縮応力を加えると、酸化アルミニウム微粒子同士が接触する部位に、過大な摩擦熱が集中して発生し、この摩擦熱で酸化アルミニウム微粒子同士が接合し、一定の機械的強度を持つ絶縁膜が容器の底面に製造される。なお、絶縁膜に加えた圧縮応力によって、扁平粉が破断したとしても、破断した扁平粉同士が、抵抗体の並列接続を形成するため、破断した扁平粉の絶縁抵抗は低下しない。また、破断した扁平粉は、接合した酸化アルミニウム微粒子の集まりで覆われているため、絶縁膜から離脱しない。
こうした考えに基づき、７段落に記載した８つの処理を連続して実施することで、形状と表面積とが自在に変えられる絶縁膜を製造する製造方法を見出した。
第一工程は、酸化アルミニウムが熱分解で析出する金属化合物を、アルコールの重量に対して１０重量％程度の割合で分散させ、アルコール分散液を作成する。これによって、金属化合物が液相化され、アルコールの粘度に近いアルコール分散液が作成される。つまり、金属化合物がアルコールに分子状態となって分散されるため、このアルコール分散液の粘度はアルコールの粘度に近い。なお、金属化合物は、汎用的な有機酸がアルミニウムと反応して合成された有機酸アルミニウム化合物で、汎用的な工業用薬品である。
第二の工程は、アルコール分散液に少量の扁平粉を混合して混合物を作成する。
第三の工程は、混合物を混合機内で回転及び揺動させる。これによって、扁平粉の集まりが、アルコール分散液中でランダムに混合される。しかし、混合機による回転と揺動だけでは、少量の扁平粉であっても、扁平粉が軽量であるため、扁平面同士が重なり合った部位が確実に分離しない。
第四の工程は、ホモジナイザー装置の稼働によって、混合物に連続して衝撃を発生させる。これによって、扁平面同士の重なり合った部位に衝撃が加わり、重なり合った部位が確実分離され、全ての扁平面が液体と接する状態になり、再度扁平面同士が重なり合うことはない。なお、ホモジナイザー装置として、超音波方式のホモジナイザー装置を用いると、扁平粉の扁平面よりさらに２桁以上小さい莫大な数の気泡の発生と気泡の消滅とが、混合物中で繰り返され（この現象をキャビテーションという）、気泡がはじける際の衝撃波が混合物の全体に繰り返し発生し、液体中では重なり合った扁平面に摩擦力が発生しないため、短時間で扁平面同士の重なった部位が、加えられた衝撃波によって分離する。
第五の工程は、処理した混合物を、底が浅い容器に充填する。
第六の工程は、容器に左右、前後、上下の３方向の振動を加える。この際、低粘度のアルコール分散液と接している扁平粉は、扁平面を重力方向に向けて液体中を移動し、容器の底面の全体に扁平粉の集まりが分散するとともに、扁平面同士の間隙に、扁平面が小さい扁平粉が入り込む配列と、アルコール分散液を介して扁平面同士が重なり合う配列が、液体中で繰り返される。最後に、上下方向の振動を加え、容器への加振を停止すると、扁平面同士がアルコール分散液を介して重なり合った扁平粉の集まりが、容器の底面の全体に形成される。なお、容器に加える振動加速度は、軽量の扁平粉を液体中で移動させるため、０．５Ｇより小さい。
第七の工程は、容器を前記金属化合物が熱分解する温度に昇温する。この際、扁平面同士の間隙を埋めて、酸化アルミニウム微粒子の集まりが析出し、また、表面の扁平面が酸化アルミニウム微粒子で覆われる。
第八の工程は、容器の底面にある絶縁膜の表面に圧縮応力を加える。この際、酸化アルミニウム微粒子同士が互いに接触する極僅かな面積からなる接触部位に、過大な摩擦熱が集中して発生し、この摩擦熱で酸化アルミニウム微粒子同士が接合し、これによって、扁平粉同士が接合され、一定の機械的強度を持つ絶縁膜が容器の底面に製造される。
この絶縁膜は容器の底面の形状からなる。また、絶縁膜の表面に、粒状の酸化アルミニウム微粒子の集まりが存在する。従って、部品や基材の導体の表面に絶縁膜を配置し、絶縁膜に圧縮応力を加えると、部品や基材の導体の表面に酸化アルミニウム微粒子の集まりが食い込み、絶縁膜が部品や基材と一体化される。
ここで、金属化合物が熱分解する際の現象を、昇温温度に即して説明する。最初にアルコールが気化し、これによって、金属化合物の微細結晶の集まりが析出し、極薄い被膜となって、重なり合った扁平面同士の間隙を埋め、また、最上部と最下部の扁平面を、金属化合物の微細結晶の集まりが覆う。次に、金属化合物が熱分解を始める温度に達すると、金属化合物が有機酸と酸化アルミニウムとに分解する。有機酸の密度が酸化アルミニウムの密度より小さいため、有機酸が上層に、酸化アルミニウムが下層に析出し、上層の有機酸が気化熱を奪って気化した後に、４０−６０ｎｍの粒状の酸化アルミニウム微粒子の集まりが、扁平面同士の間隙を埋めて析出し、また、最上部と最下部の扁平面に析出する。
この後、容器の底面に形成された絶縁膜に、圧縮応力を加える。いっぽう、酸化アルミニウム微粒子が粒状微粒子であるため、酸化アルミニウム微粒子同士は、極微小な接触面積で互いに接触する。この酸化アルミニウム微粒子の集まりに圧縮応力が加わると、酸化アルミニウムが極めて硬い物質であるため、酸化アルミニウム微粒子が破壊されることなく、極微小な接触部位に過大な摩擦熱が集中する。このため、酸化アルミニウム微粒子同士が、接触部位で互いに接合する。いっぽう、扁平面と接触する酸化アルミニウム微粒子は、扁平面に応力を加える。扁平面に加わった応力が、扁平面の破断強度より大きくなった際に、応力が加わった部位で扁平粉が破断する。しかし、扁平粉が破断しても、扁平粉が既に接合された酸化アルミニウム微粒子の集まりで覆われているため、破断した扁平粉は絶縁膜から離脱しない。また、扁平粉が破断しても、破断した扁平粉同士が接触し、破断した扁平粉が、抵抗体の並列接続を形成するため、扁平粉の絶縁抵抗は低下しない。この結果、接合した酸化アルミニウム微粒子が、全ての扁平粉を覆うとともに、酸化アルミニウム微粒子の接合によって扁平面が接合され、容器の底面に絶縁膜が形成される。
こうにして製造された絶縁膜は、次の性質を持つ。第一に、絶縁膜の表面は４０−６０ｎｍの酸化アルミニウム微粒子の集まりで覆われ、表面は鏡面研磨より１桁小さい表面粗さを持ち、表面は撥水性、防汚性の性質を持つ。第二に、絶縁膜の表面を形成する酸化アルミニウム微粒子の集まりは、絶縁膜を部品や基材の導体の表面に圧着する手段になる。このため、熱処理を伴わず、耐熱性が低い部品や基材の導体に絶縁層が形成できる。第三に、絶縁膜が、極めて安定な物質である酸化アルミニウム微粒子で覆われ、絶縁膜は継時変化しない。第四に、１０^１８Ωに及ぶ絶縁抵抗を持つ絶縁膜を製造することができる。
ここで、本絶縁膜の製造方法を、６段落に記載した５つの課題に即して説明する。
第一に、安価な材料を用い、極めて簡単な８つの処理を連続して実施することで絶縁膜が形成できる。これによって、安価な費用で絶縁膜が製造できる。
第二に、絶縁膜の表面積と形状とが、容器の底面形状によって自在に変わる。従って、用途に応じた絶縁層が導体に形成できる。
第三に、接触部位で互いに接合した酸化アルミニウム微粒子の集まりが、絶縁膜の表面を覆うため、絶縁膜を導体に圧着することで、導体の表面に絶縁層が形成できる。
第四に、少量の扁平粉を、容器の底面の全体にわたって扁平面同士が互いに重なり合うように配列させることができる。例えば、扁平面同士が３重に重なり合った絶縁膜では、３μｍ前後の厚みの絶縁層が容器の底面に形成される。
第五に、３μｍの厚みからなる絶縁膜は、抵抗率が１０^１４Ωｃｍの扁平粉を用い、幅が１ｃｍで長さが１０ｃｍの絶縁膜では、絶縁抵抗が３×１０^１８Ωになる。
この結果、５つの課題の全てが解決された。 That is, according to this manufacturing method, when eight extremely simple processes are continuously performed, an insulating film is formed on the bottom surface of the container at a low manufacturing cost. The surface area and shape of the insulating film is the shape of the bottom surface of the container. For this reason, according to the use of an insulating film, the surface area and shape of the insulating film to be manufactured can be freely changed.
That is, this manufacturing method has the following four characteristics, and thus, the manufactured insulating film has an epoch-making effect.
First, there is no restriction on the shape of the container filled with the mixture. For this reason, the surface area of the manufactured insulating film changes according to the shape of the container filled with the mixture. For example, the spot micro film of 1 mm ² up to the elongated strip-shaped insulating film exceeding 100 mm ^2, there is no form of limitation of the insulating film can be produced.
Second, the viscosity of the alcohol dispersion of the metal compound is close to that of the alcohol, and even if a small amount of the solid flat powder is mixed with the alcohol dispersion, the viscosity of the mixture does not increase. Therefore, when the mixture is filled into the container and the container is subjected to vibration in three directions, the flat surface of the flat powder moves in the alcohol dispersion liquid in the direction of gravity and is dispersed throughout the bottom surface of the container. Overlap. For example, when a small amount of flat powder is arranged on the bottom surface of the container so that the flat surfaces overlap in a triple manner, a collection of aluminum oxide fine particles forms four layers, and the flat surface layer has three layers. Then, the two are alternately overlapped to form an insulating film. The insulation resistance formed by this insulating film is determined by ignoring the presence of a small amount of aluminum oxide fine particles that fill the gaps between adjacent flat powders in the same flat layer. The layers and the three insulating resistance layers made of insulating flat powder overlap in order and are connected in parallel to form an insulating resistance. Therefore, when a flat powder having an electric resistivity of 10 ¹⁴ Ωcm is used, an insulating layer having a thickness of 3 μm, a width of 1 cm, and a length of 10 cm has an insulation resistance of 3 × 10 ¹⁸ Ω. That is, each of the insulating layers made of two kinds of insulating materials having a large electric resistivity is stacked with a thickness less than 1 μm to form an insulating layer, and these insulating layers are connected in parallel to form an insulating resistance. The insulation resistance of the insulating film is extremely large.
Third, there is no restriction on the shape of the container filled with the mixture. For this reason, the shape of the insulating film is not limited to a circle, an ellipse, and a polygon, and various shapes of insulating films can be manufactured depending on the application.
Fourth, when the metal compound is thermally decomposed, a collection of granular aluminum oxide fine particles having a size of 40 to 60 nm is deposited in the gap between the flat surfaces and the surface of the insulating film. Next, when compressive stress is applied to the surface of the insulating film formed on the bottom surface of the container, the aluminum oxide is a very hard substance having a Mohs hardness of 9, and the contact portion consisting of a small area where the aluminum oxide fine particles contact each other In addition, excessive frictional heat is concentrated and the aluminum oxide fine particles are not destroyed, but the aluminum oxide fine particles are bonded to each other by the frictional heat, and an insulating film having a certain mechanical strength is formed on the bottom surface of the container. It is formed. Therefore, a collection of granular aluminum oxide fine particles having a size of 40-60 nm exists on the surface of the manufactured insulating film. This collection of aluminum oxide fine particles serves as a means for pressure-bonding the insulating film to the conductor of the component or the substrate. For this reason, no heat treatment is required when forming an insulating film on a component or base material conductor, and an insulating film can be formed on a component or base material conductor having low heat resistance.
Here, the process leading to finding the present manufacturing method will be described. The insulating flat powder has a flat surface having a large aspect ratio, which is a ratio between the average value of the major axis and the minor axis and the thickness. Furthermore, there is variation in the size and thickness of the flat surface. In such a collection of flat powders, the flat surfaces easily overlap each other. The insulating film joined with the flat powder in which the flat surfaces overlap is broken at the portion where the flat surfaces overlap. Accordingly, it is necessary to separate the portions where the flat surfaces overlap each other. On the other hand, if an attempt is made to separate overlapping portions of flat surfaces in the atmosphere, separation is not easy because frictional force is generated in the overlapping portions. However, when a collection of flat powders is mixed in a liquid having low viscosity and an impact is generated in the liquid, the impact is transmitted to the overlapping portions of the flat surfaces, and the overlapping portions are easily separated. For this reason, it is essential to process a collection of flat powders in a low-viscosity liquid.
Furthermore, if the flat powder can be joined between flat surfaces, an insulating film having a large surface area can be formed with a small amount of flat powder. Furthermore, when a small amount of flat powder is dispersed over the entire bottom surface of the container and arranged so that the flat surfaces overlap each other, an extremely thin insulating film is formed on the bottom surface of the container, and this insulating film has a large insulation resistance. Have. For example, when the flat surfaces are arranged so as to overlap each other in a triple manner, an insulating film having a thickness of about 3 μm can be formed, and the insulating resistance is inversely proportional to the cross-sectional area of the insulating film, so that the insulating resistance is extremely large. Therefore, it is necessary to disperse the collection of flat powder over the entire bottom surface of the container and arrange the flat powder so that the flat surfaces overlap each other.
On the other hand, since the flat surfaces have a certain area, an insulating film formed by bonding flat surfaces has a certain mechanical strength because the bonding surfaces have a certain area. Therefore, the process which arrange | positions flat powder is needed so that the flat surfaces of flat powder may overlap. By the way, when vibrations in three directions are applied to a collection of flat powder in the liquid filled in the container, the flat surface moves in the liquid in the direction of gravity, and the arrangement of the flat surfaces in the direction of gravity is repeated. When the vibration is stopped, the flat surfaces overlap with each other through the liquid. For this reason, the process which mixes the collection of flat powder with a liquid, fills this mixture with a container, and applies a vibration to a container is needed.
Furthermore, the insulating flat powder has variations in the average value and thickness of the major axis and minor axis of the flat surface. An insulating film is manufactured using such flat powder as a raw material. However, if the substance that joins the flat surfaces is a fine particle of several tens of nanometers that is two orders of magnitude or more smaller than the flat surfaces, a collection of fine particles is surely deposited on the flat surfaces. In addition, fine particles are deposited in preference to a flat surface having a large area. Furthermore, even if there is variation in the size of the flat surface, since the flat surface is two orders of magnitude larger than the size of the fine particles, the fine particles are surely deposited on the flat surface. Further, if the fine particles are granular, the fine particles come into contact with each other at a contact portion having a very narrow contact area when the collection of fine particles is precipitated. Furthermore, if the hardness of the fine particles is high, when compressive stress is applied to the collection of fine particles, the fine particles are not destroyed, and frictional heat is concentrated at the contact portion between the fine particles, and the fine particles are joined by this frictional heat. The means for joining flat surfaces to each other is formed by depositing a collection of granular particles having high hardness on the flat surfaces, applying compressive stress to the collection of fine particles, and joining the fine particles with each other by frictional heat. The means to join becomes effective. As a substance constituting such fine particles, aluminum oxide (also referred to as alumina) having a high resistivity of 10 ¹⁴ Ωcm, a high hardness of Mohs hardness of 9, and a high heat resistance exceeding 1500 ° C. which does not change due to frictional heat. is there.
Therefore, in the manufacturing method for manufacturing the insulating film, first, the raw material of the aluminum oxide fine particles is made into a liquid phase, and a small amount of flat powder is mixed with this liquid to create a mixture. Second, the portion where the flat surfaces overlap is separated in the liquid. As a result, all the flat powder comes into contact with the liquid. Third, the mixture is filled into a container. Fourth, a small amount of flat powder is dispersed over the entire bottom surface of the container, and the flat surfaces overlap each other. For this reason, the vibration of 3 directions is repeatedly applied to a container, flat powder is disperse | distributed to the whole bottom face of a container, and the process which flat surfaces overlap is performed. Fifth, the temperature of the container is raised, the raw material of the aluminum oxide fine particles is pyrolyzed, and a collection of aluminum oxide fine particles is precipitated. That is, the means for depositing aluminum oxide by thermal decomposition is the simplest. Thereby, a collection of granular aluminum oxide fine particles having a size of 40 to 60 nm is deposited in the gap between the flat surfaces of the flat powder and the surface of the insulating film. Finally, when compressive stress is applied to the surface of the insulating film formed on the bottom surface of the container, excessive frictional heat is concentrated at the site where the aluminum oxide particles are in contact with each other. And an insulating film having a certain mechanical strength is manufactured on the bottom surface of the container. Even if the flat powder is broken by the compressive stress applied to the insulating film, the broken flat powders form a parallel connection of the resistors, so that the insulation resistance of the broken flat powder does not decrease. Further, the broken flat powder is covered with a collection of bonded aluminum oxide fine particles and thus does not leave the insulating film.
Based on this idea, the inventors have found a manufacturing method for manufacturing an insulating film whose shape and surface area can be freely changed by continuously performing the eight processes described in the seventh paragraph.
In the first step, a metal compound in which aluminum oxide is precipitated by thermal decomposition is dispersed at a ratio of about 10% by weight with respect to the weight of the alcohol to prepare an alcohol dispersion. As a result, the metal compound is converted into a liquid phase and an alcohol dispersion close to the viscosity of the alcohol is produced. That is, since the metal compound is dispersed in a molecular state in the alcohol, the viscosity of the alcohol dispersion is close to that of the alcohol. The metal compound is an organic acid aluminum compound synthesized by reacting a general-purpose organic acid with aluminum, and is a general-purpose industrial chemical.
In the second step, a small amount of flat powder is mixed with the alcohol dispersion to create a mixture.
The third step rotates and rocks the mixture in the mixer. As a result, a collection of flat powders is randomly mixed in the alcohol dispersion. However, even if only a small amount of flat powder is rotated and swung by the mixer, the flat powder is lightweight, and the portion where the flat surfaces overlap is not reliably separated.
In the fourth step, the mixture is continuously impacted by the operation of the homogenizer device. As a result, an impact is applied to the overlapping portions of the flat surfaces, the overlapping portions are reliably separated, all the flat surfaces are in contact with the liquid, and the flat surfaces do not overlap again. When an ultrasonic homogenizer is used as the homogenizer, the generation of a huge number of bubbles that are two orders of magnitude smaller than the flat surface of the flat powder and the disappearance of the bubbles are repeated in the mixture. This is called cavitation, and the shock wave generated when bubbles are repetitively generated in the entire mixture. In the liquid, frictional force is not generated on the overlapping flat surfaces, so the portions where the flat surfaces overlap each other are applied in a short time. Separate by.
In the fifth step, the treated mixture is filled into a shallow container.
In the sixth step, vibrations in three directions, left, right, front, back, and top, are applied to the container. At this time, the flat powder in contact with the low-viscosity alcohol dispersion moves in the liquid with the flat surface directed in the direction of gravity, and the collection of flat powder is dispersed over the entire bottom surface of the container. The arrangement in which the flat powder having a small flat surface enters the gap and the arrangement in which the flat surfaces overlap with each other through the alcohol dispersion are repeated in the liquid. Finally, when vibration in the vertical direction is applied and vibration to the container is stopped, a collection of flat powders in which the flat surfaces overlap with each other through the alcohol dispersion liquid is formed on the entire bottom surface of the container. The vibration acceleration applied to the container is smaller than 0.5 G in order to move the light flat powder in the liquid.
In the seventh step, the container is heated to a temperature at which the metal compound is thermally decomposed. At this time, the gap between the flat surfaces is filled, a collection of aluminum oxide fine particles is deposited, and the flat surface of the surface is covered with the aluminum oxide fine particles.
In the eighth step, compressive stress is applied to the surface of the insulating film on the bottom surface of the container. At this time, excessive frictional heat is concentrated at the contact area consisting of a very small area where the aluminum oxide fine particles are in contact with each other, and the aluminum oxide fine particles are joined by this frictional heat. And an insulating film having a certain mechanical strength is manufactured on the bottom surface of the container.
This insulating film has the shape of the bottom surface of the container. In addition, a collection of granular aluminum oxide fine particles exists on the surface of the insulating film. Therefore, when an insulating film is placed on the surface of a component or base material conductor and a compressive stress is applied to the insulating film, a collection of aluminum oxide particles bites into the surface of the component or base material conductor, and the insulating film becomes a part or base material. And integrated.
Here, the phenomenon when the metal compound is thermally decomposed will be described according to the temperature rise. At first, the alcohol vaporizes, and as a result, a collection of fine crystals of the metal compound precipitates, forming an extremely thin film, filling the gaps between the overlapping flat surfaces, and the top and bottom flat surfaces, Covered by a collection of fine crystals of metal compound. Next, when the metal compound reaches a temperature at which thermal decomposition starts, the metal compound decomposes into an organic acid and aluminum oxide. Since the density of the organic acid is smaller than that of aluminum oxide, the organic acid is deposited on the upper layer, the aluminum oxide is deposited on the lower layer, and the upper layer organic acid is vaporized by removing the heat of vaporization. Are deposited in the gap between the flat surfaces, and also deposited on the uppermost and lowermost flat surfaces.
Thereafter, compressive stress is applied to the insulating film formed on the bottom surface of the container. On the other hand, since the aluminum oxide fine particles are granular fine particles, the aluminum oxide fine particles are in contact with each other with a very small contact area. When compressive stress is applied to the aggregate of the aluminum oxide fine particles, the aluminum oxide is an extremely hard substance, and therefore, the aluminum oxide fine particles are not destroyed, and excessive frictional heat is concentrated on a very small contact portion. For this reason, the aluminum oxide fine particles are bonded to each other at the contact site. On the other hand, the aluminum oxide fine particles in contact with the flat surface apply stress to the flat surface. When the stress applied to the flat surface becomes larger than the breaking strength of the flat surface, the flat powder breaks at the site where the stress is applied. However, even if the flat powder breaks, the flat powder that has already been bonded is covered with a collection of joined aluminum oxide fine particles, so that the broken flat powder does not leave the insulating film. Even if the flat powder breaks, the broken flat powders come into contact with each other, and the broken flat powder forms a parallel connection of the resistors, so that the insulation resistance of the flat powder does not decrease. As a result, the joined aluminum oxide fine particles cover all the flat powder, and the flat surfaces are joined by joining the aluminum oxide fine particles, so that an insulating film is formed on the bottom surface of the container.
The insulating film thus manufactured has the following properties. First, the surface of the insulating film is covered with a collection of aluminum oxide fine particles of 40 to 60 nm, the surface has a surface roughness one order of magnitude smaller than that of mirror polishing, and the surface has water repellency and antifouling properties. Second, the collection of aluminum oxide fine particles forming the surface of the insulating film becomes a means for pressure-bonding the insulating film to the surface of the component or the conductor of the substrate. For this reason, an insulating layer can be formed on a part or a conductor of a substrate having low heat resistance without heat treatment. Third, the insulating film is covered with aluminum oxide fine particles, which is a very stable substance, and the insulating film does not change over time. Fourth, an insulating film having an insulation resistance of 10 ¹⁸ Ω can be manufactured.
Here, the manufacturing method of this insulating film will be described in accordance with the five problems described in the sixth paragraph.
First, an insulating film can be formed by continuously performing eight extremely simple processes using an inexpensive material. Thereby, an insulating film can be manufactured at low cost.
Second, the surface area and shape of the insulating film can be freely changed depending on the shape of the bottom surface of the container. Therefore, an insulating layer according to the application can be formed on the conductor.
Third, since the collection of aluminum oxide fine particles bonded to each other at the contact portion covers the surface of the insulating film, the insulating layer can be formed on the surface of the conductor by pressing the insulating film to the conductor.
Fourth, a small amount of flat powder can be arranged so that the flat surfaces overlap each other over the entire bottom surface of the container. For example, in an insulating film in which the flat surfaces overlap in a triple manner, an insulating layer having a thickness of about 3 μm is formed on the bottom surface of the container.
Fifth, an insulating film having a thickness of 3 μm uses flat powder having a resistivity of 10 ¹⁴ Ωcm, and an insulating film having a width of 1 cm and a length of 10 cm has an insulation resistance of 3 × 10 ¹⁸ Ω.
As a result, all the five problems were solved.

７段落に記載した絶縁膜の製造方法において、前記絶縁性扁平粉が、ガラス、マイカ、アルミナ、シリカまたは窒化ホウ素からなるいずれか1種類の材質の扁平粉である、７段落に記載した絶縁膜の製造方法である。 The insulating film described in the seventh paragraph, wherein the insulating flat powder is a flat powder of any one material made of glass, mica, alumina, silica, or boron nitride. It is a manufacturing method.

つまり、こうした扁平粉を構成する絶縁物の電気抵抗率は、いずれも１０^１４Ωｃｍ以上の高い絶縁性を持つ。絶縁膜の絶縁抵抗は、扁平粉の電気抵抗率に比例するため、極めて大きな絶縁抵抗を持つ絶縁膜が製造される。なお、ガラス扁平粉では、ソーダ石灰ガラスのみが１０^１２Ωｃｍの電気抵抗率を持つ。また、絶縁性の扁平粉としてヘマタイト（酸化第二鉄Ｆｅ_２Ｏ_３のアルファ相からなる物質）の扁平粉が存在するが、電気抵抗率は１０^８Ωｃｍと低い。いっぽう、上記の絶縁物のモース硬度は、窒化ホウ素が２で、マイカ（雲母とも言う）が２．８−３．０で、ガラスが５で、シリカが７で、いずれもアルミナ（酸化アルミニウムを意味する）の９より低い。従って、７段落で説明したように、容器の底面に形成された絶縁膜を圧縮した際に、硬度が低い絶縁物からなる扁平粉ほど、酸化アルミニウム微粒子による応力で破断する恐れがある。しかし、破断した扁平粉が抵抗の並列接続を形成し、絶縁膜の抵抗は低下しない。また、破断した扁平粉は、接合した酸化アルミニウム微粒子の集まりで覆われ、絶縁膜から離脱しない。
以上に説明したように、ガラス、マイカ、アルミナ、シリカまたは窒化ホウ素からなるいずれか1種類の扁平粉を、７段落に記載した絶縁膜の製造方法における絶縁性扁平粉として用い、７段落に記載した製造方法に従って絶縁膜を製造すると、容器の底面に絶縁抵抗が極めて大きい絶縁膜が製造される。 That is, the electrical resistivity of the insulator constituting such a flat powder has a high insulation property of 10 ¹⁴ Ωcm or more. Since the insulation resistance of the insulation film is proportional to the electrical resistivity of the flat powder, an insulation film having an extremely large insulation resistance is manufactured. In the flat glass powder, only soda-lime glass has an electrical resistivity of 10 ¹² Ωcm. In addition, a flat powder of hematite (a substance composed of an alpha phase of ferric oxide Fe ₂ O ₃ ) exists as an insulating flat powder, but its electrical resistivity is as low as 10 ⁸ Ωcm. On the other hand, the Mohs hardness of the above insulator is 2 for boron nitride, 2.8-3.0 for mica (also referred to as mica), 5 for glass, 7 for silica, and both alumina (aluminum oxide). Meaning 9). Therefore, as described in the seventh paragraph, when the insulating film formed on the bottom surface of the container is compressed, the flat powder made of an insulator having a lower hardness may be broken by the stress caused by the aluminum oxide fine particles. However, the broken flat powder forms a parallel connection of resistance, and the resistance of the insulating film does not decrease. Further, the broken flat powder is covered with a collection of bonded aluminum oxide fine particles and does not leave the insulating film.
As explained above, any one flat powder made of glass, mica, alumina, silica or boron nitride is used as the insulating flat powder in the method for producing an insulating film described in the seventh paragraph, and is described in the seventh paragraph. When an insulating film is manufactured according to the manufacturing method described above, an insulating film having an extremely high insulation resistance is manufactured on the bottom surface of the container.

７段落に記載した絶縁膜の製造方法において、前記酸化アルミニウムを熱分解で析出する金属化合物が、カプリル酸アルミニウム、安息香酸アルミニウム、ナフテン酸アルミニウムからなるいずれか１種類のカルボン酸アルミニウム化合物である、７段落に記載した絶縁膜の製造方法である。 In the method for producing an insulating film described in paragraph 7, the metal compound for depositing aluminum oxide by pyrolysis is any one aluminum carboxylate compound composed of aluminum caprylate, aluminum benzoate, and aluminum naphthenate. It is a manufacturing method of the insulating film described in the seventh paragraph.

つまり、こうしたカルボン酸アルミニウム化合物は、熱分解で酸化アルミニウムを析出する。従って、７段落に記載した絶縁膜の製造方法において、酸化アルミニウムを熱分解で析出する金属化合物として、上記のカルボン酸アルミニウム化合物を用い、７段落に記載した製造方法に従って絶縁膜を製造すると、容器の底面に絶縁膜が製造される。いっぽう、酸化アルミニウムは、熱伝導率が４０Ｗ／ｍＫで、金属酸化物の中では優れた熱伝導性を持つ。また、１０^１４Ωｃｍ以上の抵抗率を持つ絶縁体で、化学的に安定な酸化物で耐食性に優れ、モース硬度が９からなる硬い物質で、耐熱温度が１５００℃である。このため、絶縁膜の表面は、電気絶縁性と熱伝導性と耐食性と耐熱性の性質を持つ。従って、絶縁膜の表面は硬く、絶縁膜を部品や基材の導体の表面に配置し、絶縁膜に圧縮応力を加えると、絶縁膜の表面の酸化アルミニウム微粒子が導体の表面に食い込み、絶縁膜が導体に圧着し、導体の表面が絶縁化される。
つまり、カルボン酸のカルボキシル基を構成する酸素イオンが配位子になって、アルミニウムイオンに配位結合するカルボン酸アルミニウム化合物は、熱分解によって酸化アルミニウムを析出する。このため、７段落に記載した絶縁膜の製造方法において、酸化アルミニウムを熱分解で析出する金属化合物として、カルボン酸アルミニウム化合物を用い、７段落に記載した製造方法に従って絶縁膜を製造すると、絶縁膜が容器の底面に製造される。なお、カルボン酸アルミニウム化合物の熱分解温度は、ナフテン酸アルミニウムが３３０℃で熱分解する温度が最も高い。また、カルボン酸アルミニウム化合物の大気雰囲気での熱分解は、窒素雰囲気での熱分解より３０−５０℃低いため、大気雰囲気での熱分解は、熱処理費用が安価で済む。また、これらのカルボン酸アルミニウム化合物は、メタノールに１０重量％近くまで分散する。
すなわち、カルボキシル基を構成する酸素イオンが配位子になって、アルミニウムイオンに近づいて配位結合するカルボン酸アルミニウム化合物は、最も大きいイオンであるアルミニウムイオンに酸素イオンが近づいて配位結合するため、両者の距離は短くなる。このため、アルミニウムイオンに配位結合する酸素イオンが、アルミニウムイオンの反対側で共有結合するイオンとの距離が最も長くなる。こうした分子構造上の特徴を持つカルボン酸アルミニウム化合物は、カルボン酸アルミニウム化合物を構成するカルボン酸の沸点を超えると、カルボキシル基を構成する酸素イオンがアルミニウムイオンの反対側で共有結合するイオンとの結合部が最初に分断され、アルミニウムイオンと酸素イオンとの化合物である酸化アルミニウムとカルボン酸とに分解する。さらに昇温すると、カルボン酸が気化熱を奪って気化し、カルボン酸の気化が完了した時点で、酸化アルミニウムが析出する。こうしたカルボン酸アルミニウム化合物として、酢酸アルミニウム、カプリル酸アルミニウム、安息香酸アルミニウム、ナフテン酸アルミニウムなどがある。
なお、酢酸アルミニウムは、熱分解でアモルファス化した酸化アルミニウムを析出し、アモルファス化した酸化アルミニウムの組成は、Ａｌ_２Ｏ_３の組成からずれ、電気抵抗率は１０^１４Ωｃｍより著しく低い。このため、熱分解で酸化アルミニウムを析出するカルボン酸アルミニウム化合物は、カプリル酸アルミニウム、安息香酸アルミニウム、ナフテン酸アルミニウムからなるいずれか１種類のカルボン酸アルミニウム化合物が望ましい。
また、前記したカルボン酸アルミニウム化合物は、いずれも容易に合成できる安価な工業用薬品である。すなわち、汎用的なカルボン酸を強アルカリと反応させるとカルボン酸アルカリ金属化合物が生成される。この後、カルボン酸アルカリ金属化合物を、無機アルミニウム化合物と反応させると、カルボン酸アルミニウム化合物が合成される。また、原料となるカルボン酸は、有機酸の沸点の中で相対的に低い沸点を有する有機酸であり、大気雰囲気においては３３０℃程度の低い熱処理温度で、酸化アルミニウムが析出する。
以上に説明したように、７段落に記載した絶縁膜の製造方法において、酸化アルミニウムが熱分解で析出する金属化合物として、カプリル酸アルミニウム、安息香酸アルミニウム、ナフテン酸アルミニウムからなるいずれか１種類のカルボン酸アルミニウム化合物を用い、７段落に記載した製造方法に従って絶縁膜を製造すると、絶縁抵抗が大きい絶縁膜が容器の底面に製造される。 That is, such an aluminum carboxylate compound precipitates aluminum oxide by thermal decomposition. Therefore, in the method for manufacturing an insulating film described in the seventh paragraph, when the above-described aluminum carboxylate compound is used as a metal compound for depositing aluminum oxide by thermal decomposition, and the insulating film is manufactured according to the manufacturing method described in the seventh paragraph, An insulating film is manufactured on the bottom surface of the substrate. On the other hand, aluminum oxide has a thermal conductivity of 40 W / mK, and has excellent thermal conductivity among metal oxides. Further, it is an insulator having a resistivity of 10 ¹⁴ Ωcm or more, a chemically stable oxide, excellent in corrosion resistance, a hard substance having a Mohs hardness of 9, and a heat resistant temperature of 1500 ° C. For this reason, the surface of the insulating film has properties of electrical insulation, thermal conductivity, corrosion resistance, and heat resistance. Therefore, the surface of the insulating film is hard, and when the insulating film is placed on the surface of the conductor of the component or the substrate and compressive stress is applied to the insulating film, the aluminum oxide fine particles on the surface of the insulating film bite into the surface of the conductor, Is crimped to the conductor, and the surface of the conductor is insulated.
That is, the oxygen ion constituting the carboxyl group of the carboxylic acid serves as a ligand, and the aluminum carboxylate compound coordinated to the aluminum ion precipitates aluminum oxide by thermal decomposition. For this reason, in the manufacturing method of an insulating film described in the seventh paragraph, when an insulating film is manufactured according to the manufacturing method described in the seventh paragraph using an aluminum carboxylate compound as a metal compound for depositing aluminum oxide by thermal decomposition, the insulating film Is manufactured on the bottom of the container. The thermal decomposition temperature of the aluminum carboxylate compound is the highest at which the aluminum naphthenate thermally decomposes at 330 ° C. In addition, the thermal decomposition of the aluminum carboxylate compound in the air atmosphere is 30-50 ° C. lower than the thermal decomposition in the nitrogen atmosphere, so that the thermal decomposition in the air atmosphere can be inexpensive in heat treatment. These aluminum carboxylate compounds are dispersed in methanol up to nearly 10% by weight.
That is, the oxygen ion constituting the carboxyl group becomes a ligand, and the carboxylate aluminum compound that is coordinated and bonded to the aluminum ion is coordinated and bonded to the aluminum ion that is the largest ion. The distance between the two becomes shorter. Therefore, the distance between the oxygen ion coordinated to the aluminum ion and the ion covalently bonded on the opposite side of the aluminum ion is the longest. When the carboxylate aluminum compound having such molecular structure characteristics exceeds the boiling point of the carboxylic acid constituting the carboxylate aluminum compound, the oxygen ion constituting the carboxyl group is bonded to the ion covalently bonded to the opposite side of the aluminum ion. The part is first divided and decomposed into aluminum oxide and carboxylic acid, which are compounds of aluminum ions and oxygen ions. When the temperature is further raised, the carboxylic acid takes the heat of vaporization and vaporizes, and when the vaporization of the carboxylic acid is completed, aluminum oxide is deposited. Examples of such aluminum carboxylate compounds include aluminum acetate, aluminum caprylate, aluminum benzoate, and aluminum naphthenate.
Note that aluminum acetate precipitates aluminum oxide that has been amorphized by thermal decomposition, and the composition of the amorphized aluminum oxide deviates from the composition of Al ₂ O ₃ , and the electrical resistivity is significantly lower than 10 ¹⁴ Ωcm. For this reason, the aluminum carboxylate compound that deposits aluminum oxide by thermal decomposition is preferably any one of aluminum carboxylate compounds composed of aluminum caprylate, aluminum benzoate, and aluminum naphthenate.
In addition, the above-described aluminum carboxylate compound is an inexpensive industrial chemical that can be easily synthesized. That is, when a general-purpose carboxylic acid is reacted with a strong alkali, a carboxylic acid alkali metal compound is produced. Thereafter, when the alkali metal carboxylate compound is reacted with the inorganic aluminum compound, the aluminum carboxylate compound is synthesized. The carboxylic acid as a raw material is an organic acid having a relatively low boiling point among the boiling points of organic acids, and aluminum oxide is deposited at a low heat treatment temperature of about 330 ° C. in the air atmosphere.
As described above, in the method for manufacturing an insulating film described in the seventh paragraph, any one of the carboxyls composed of aluminum caprylate, aluminum benzoate, and aluminum naphthenate is used as the metal compound from which aluminum oxide is deposited by thermal decomposition. When an insulating film is manufactured according to the manufacturing method described in the seventh paragraph using an aluminum acid compound, an insulating film having a large insulation resistance is manufactured on the bottom surface of the container.

酸化アルミニウム微粒子の集まりを介して、ガラスの扁平面が３層をなして扁平面同士で重なり合って接合した絶縁膜の断面を模式的に示した説明図である。It is explanatory drawing which showed typically the cross section of the insulating film which the flat surface of glass formed the three layers through the collection of aluminum oxide fine particles, and the flat surfaces overlapped and joined.

実施例１
本実施例では、ガラス扁平粉を酸化アルミニウム微粒子の集まりで接合して絶縁膜を製造する。ガラス扁平粉（日本板硝子株式会社のＭＥＧ−１６０）は、鱗片形状で無アルカリガラス（Ｅガラスとも言う）からなり、抵抗率が１０^１６Ωｃｍで、軟化点が８４０℃で、平均厚みが０．７μｍで、平均粒径が１６０μｍである。また、酸化アルミニウム微粒子の原料は、熱分解温度が３１０℃の安息香酸アルミニウムＡｌ（Ｃ_６Ｈ_５ＣＯＯ）_３（三津和化学薬品株式会社の製品）を用いた。
最初に、安息香酸アルミニウムを１０重量％の割合でメタノールに分散させた。このアルコール分散液の１００ｃｃに、３ｇのガラス扁平粉を混合した。この混合物を、回転による拡散混合と揺動による移動混合とを同時に行う装置（愛知電機株式会社のロッキングミキサーＲＭＨ−ＨＴ）に充填し、回転と揺動を繰り返して混合物を作成した。この混合物をビーカーに充填し、超音波ホモジナイザー装置（ヤマト科学株式会社の製品ＬＵＨ３００）によって、２０ｋＨｚの超音波振動をビーカーに１分間加えた。この後、混合物を１０ｍｍ×１００ｍｍ×５ｍｍの細長い短冊状の容器に充填し、この容器を小型加振機の加振台の上に載せ、左右、前後、上下の３方向に、０．３Ｇの振動加速度を５秒間ずつ３回繰り返し、最後に、上下方向に０．３Ｇの振動加速度を１０秒間加えた。この後、容器を大気雰囲気の熱処理炉に入れ、メタノールを気化させた後に、３１０℃で２分間熱処理し、短冊状の厚みが極薄い試料を容器の底面に作成した。なお、メタノールと安息香酸とは沸点が異なるため、気化したメタノールと安息香酸とは、回収機で個別に回収した。この後、試料の表面に３ｋｇに相当する荷重を加えた。さらに、絶縁抵抗計で試料の抵抗を測定したところ、針が振り切れ、抵抗値は１００ＭΩより大きい値であった。
この後、試料を試料と同じ幅の銅板の上に配置し、試料の表面に５ｋｇに相当する荷重を加え、銅板に圧着させた。圧着した試料を、ＪＩＳＫ６８５４−１の剥離接着強さ試験方法による剥離試験で、試料は８００ｇ重の引っ張り力に耐えられたため、絶縁層は、導体表面に対し十分な密着力を持つ。
この後、剥離試験に用いた試料の表面を電子顕微鏡で観察と分析を行なった。さらに、試料の中央部で幅方向に試料を切断し、断面を電子顕微鏡で観察と分析を行なった。電子顕微鏡は、ＪＦＥテクノリサーチ株式会社の極低加速電圧ＳＥＭを用いた。この装置は、１００Ｖからの極低加速電圧による観察が可能で、試料に導電性の被膜を形成せずに直接試料が観察できる。
最初に、試料の表面からの反射電子線の９００−１０００Ｖの間にある２次電子線を取り出して画像処理を行った。試料の表面は、４０−６０ｎｍの大きさからなる微粒子の集まりで覆われていた。次に、試料の表面からの反射電子線について、９００−１０００Ｖの間にあるエネルギーを抽出して画像処理を行い、画像の濃淡で粒状微粒子の材質を分析した。いずれの粒状微粒子にも濃淡が認められたので、複数原子から構成されていることが分かった。さらに、特性エックス線のエネルギーとその強度を画像処理し、粒子を構成する元素の種類を分析した。アルミニウム原子と酸素原子とで構成されていたため、微粒子は酸化アルミニウム微粒子である。
さらに、試料の断面からの反射電子線の９００−１０００Ｖの間にある２次電子線を取り出して画像処理を行った。試料の厚みは３μｍであり、酸化アルミニウム微粒子の集まりを介して、扁平面が３層をなして扁平面同士で重なり合って接合し、試料を形成していた。図１は、試料の断面の一部を模式的に拡大した図である。１は酸化アルミニウム微粒子で、２はガラス扁平粉である。
なお、作成した試料が形成する絶縁抵抗の理論値は、扁平面の同一層における隣接する扁平粉の間隙を埋める僅かな量の酸化アルミニウム微粒子の集まりの存在を無視すると、厚みが０．３μｍの酸化アルミニウム層が４層をなし、ガラス層が３層をなし、これらの絶縁層が交互に積層して並列接続して電気抵抗を構成すると、絶縁膜の絶縁抵抗は８．１×１０^１８Ωになる。この絶縁膜の抵抗値は、２種類の絶縁層が交互に積み重なって並列接続するため、相対的に抵抗値が小さい酸化アルミニウムの絶縁層の抵抗値が、絶縁膜の抵抗値に大きく寄与する。つまり、ガラス扁平粉の抵抗率が１０^１６Ωｃｍと絶縁性が高いことによる。 Example 1
In this embodiment, the glass flat powder is joined with a collection of aluminum oxide fine particles to produce an insulating film. Glass flat powder (MEG-160 from Nippon Sheet Glass Co., Ltd.) is made of scale-free and non-alkali glass (also called E glass), has a resistivity of 10 ¹⁶ Ωcm, a softening point of 840 ° C., and an average thickness of 0.00. The average particle diameter is 7 μm and 160 μm. Moreover, aluminum benzoate Al (C ₆ H ₅ COO) ₃ (product of Mitsuwa Chemicals Co., Ltd.) having a thermal decomposition temperature of 310 ° C. was used as a raw material for the aluminum oxide fine particles.
First, aluminum benzoate was dispersed in methanol at a ratio of 10% by weight. 3 g of glass flat powder was mixed with 100 cc of this alcohol dispersion. This mixture was filled in a device (a rocking mixer RMH-HT manufactured by Aichi Electric Co., Ltd.) that simultaneously performs diffusion mixing by rotation and moving mixing by oscillation, and the mixture was prepared by repeating rotation and oscillation. This mixture was filled in a beaker, and ultrasonic vibration of 20 kHz was applied to the beaker for 1 minute by an ultrasonic homogenizer (product LUH300 manufactured by Yamato Scientific Co., Ltd.). After that, the mixture is filled into a 10 mm × 100 mm × 5 mm elongated strip-shaped container, and this container is placed on a shaking table of a small shaker, and 0.3 G in three directions, left, right, front, back, top and bottom. The vibration acceleration was repeated 3 times for 5 seconds, and finally 0.3 G vibration acceleration was applied for 10 seconds in the vertical direction. Thereafter, the container was placed in a heat treatment furnace in an atmospheric atmosphere to vaporize methanol, and then heat-treated at 310 ° C. for 2 minutes to prepare a sample having a very thin strip shape on the bottom surface of the container. In addition, since methanol and benzoic acid have different boiling points, vaporized methanol and benzoic acid were individually recovered by a recovery machine. Thereafter, a load corresponding to 3 kg was applied to the surface of the sample. Furthermore, when the resistance of the sample was measured with an insulation resistance meter, the needle was shaken out and the resistance value was greater than 100 MΩ.
Thereafter, the sample was placed on a copper plate having the same width as the sample, a load corresponding to 5 kg was applied to the surface of the sample, and the sample was pressure bonded to the copper plate. In the peel test according to the peel adhesion strength test method of JIS K6854-1, the pressure-bonded sample was able to withstand a tensile force of 800 g, so that the insulating layer has sufficient adhesion to the conductor surface.
Thereafter, the surface of the sample used for the peel test was observed and analyzed with an electron microscope. Furthermore, the sample was cut in the width direction at the center of the sample, and the cross section was observed and analyzed with an electron microscope. The electron microscope used was an ultra-low acceleration voltage SEM from JFE Techno-Research Corporation. This apparatus can be observed with an extremely low acceleration voltage from 100 V, and the sample can be directly observed without forming a conductive film on the sample.
First, a secondary electron beam between 900-1000 V of the reflected electron beam from the surface of the sample was taken out and image processing was performed. The surface of the sample was covered with a collection of fine particles having a size of 40-60 nm. Next, with respect to the reflected electron beam from the surface of the sample, energy between 900 and 1000 V was extracted and image processing was performed, and the material of the granular fine particles was analyzed based on the density of the image. Since all the granular fine particles were observed to be shaded, it was found that they were composed of a plurality of atoms. Furthermore, the energy and intensity of characteristic X-rays were image-processed, and the types of elements constituting the particles were analyzed. Since it is composed of aluminum atoms and oxygen atoms, the fine particles are aluminum oxide fine particles.
Furthermore, the secondary electron beam between 900-1000 V of the reflected electron beam from the cross section of the sample was taken out and image processing was performed. The thickness of the sample was 3 μm, and the flat surfaces formed three layers through the collection of aluminum oxide fine particles, and the flat surfaces overlapped and joined to form a sample. FIG. 1 is a schematic enlarged view of a part of a cross section of a sample. 1 is aluminum oxide fine particles, and 2 is glass flat powder.
It should be noted that the theoretical value of the insulation resistance formed by the prepared sample is 0.3 μm in thickness, ignoring the presence of a small amount of aluminum oxide fine particles that fill the gaps between adjacent flat powders in the same flat layer. When the aluminum oxide layer has four layers, the glass layer has three layers, and these insulating layers are alternately stacked and connected in parallel to form an electrical resistance, the insulating resistance of the insulating film is 8.1 × 10 ¹⁸ Ω become. Since the two insulating layers are alternately stacked and connected in parallel, the resistance value of the insulating film greatly contributes to the resistance value of the insulating film. That is, the resistivity of the glass flat powder is 10 ¹⁶ Ωcm, which is high in insulation.

実施例２
本実施例では、窒化ホウ素の扁平粉を、酸化アルミニウム微粒子の集まりで接合して絶縁膜を製造する。窒化ホウ素扁平粉（昭和電工株式会社のＵＨＰ−２）は、鱗片形状の窒化ホウ素粉で、抵抗率が１０^１４Ωｃｍで、平均粒径が１１μｍで、ＢＥＴ比表面積が３−５ｍ^２／ｇである。また、酸化アルミニウム微粒子の原料は、実施例１の安息香酸アルミニウムを用いた。
最初に、安息香酸アルミニウムを１０重量％の割合でメタノールに分散させた。このアルコール分散液の１００ｃｃに、４ｇの窒化ホウ素の扁平粉を混合した。この混合物に、実施例１と同様に、回転と揺動を繰り返して混合物を作成した。この混合物をビーカーに充填し、実施例１と同様に、ビーカーに２０ｋＨｚの超音波振動を１分間加えた。この後、混合物を実施例１で用いた細長い短冊状の容器に充填し、この容器を小型加振機の加振台の上に載せ、実施例１と同じ条件で容器に振動を加えた。この後、容器を大気雰囲気の熱処理炉に入れ、実施例１と同じ条件で熱処理した。なお、メタノールと安息香酸とは沸点が異なるため、気化したメタノールと安息香酸とは、回収機で個別に回収した。この後、試料の表面に２ｋｇに相当する荷重を加えた。また、絶縁抵抗計で試料の抵抗を測定したところ、針が振り切れ、抵抗値は１００ＭΩより大きい値であった。
この後、実施例1と同様に、試料を試料と同じ幅の銅板の上に配置し、試料の表面に３ｋｇに相当する荷重を加え、銅板に圧着させた。圧着した試料は６００ｇ重の引っ張り力に耐えられたため、導体表面への絶縁層の十分な接着力を持つ。
この後、剥離試験に用いた試料の表面を、実施例1と同様に、電子顕微鏡で観察と分析を行なった。さらに、試料の中央部で幅方向に試料を切断し、断面を電子顕微鏡で観察と分析を行なった。
試料の表面は、酸化アルミニウムの４０−６０ｎｍの粒状微粒子で覆われていた。試料の断面の観察から、試料の厚みは３．２μｍであり、酸化アルミニウム微粒子の集まりを介して、扁平面が３層をなして扁平面同士で重なり合って接合し、試料を形成していた。
なお、作成した試料が形成する絶縁抵抗の理論値は、実施例1と同様に、扁平面の同一層における隣接する扁平粉の間隙を埋める僅かな量の酸化アルミニウム微粒子の集まりの存在を無視すると、厚みが０．３μｍの酸化アルミニウム層が４層をなし、窒化ホウ素層が３層をなし、これらの絶縁層が交互に積層して並列接続して電気抵抗を構成すると、絶縁膜の抵抗は３．１×１０^１８Ωになる。実施例１と比べると、窒化ホウ素の電気抵抗率が、Ｅガラスの電気抵抗率より２桁小さく、酸化アルミニウムの電気抵抗率に近いため、窒化ホウ素の絶縁層の抵抗値が、酸化アルミニウムの絶縁層の抵抗値に近づく。このため、両者が形成する絶縁抵抗によって、絶縁膜の絶縁抵抗が決まる。 Example 2
In this embodiment, a flat powder of boron nitride is joined with a collection of aluminum oxide fine particles to produce an insulating film. Boron nitride flat powder (UHP-2 from Showa Denko KK) is a scale-shaped boron nitride powder having a resistivity of 10 ¹⁴ Ωcm, an average particle size of 11 μm, and a BET specific surface area of 3-5 m ² / g. is there. Moreover, the aluminum benzoate of Example 1 was used as the raw material for the aluminum oxide fine particles.
First, aluminum benzoate was dispersed in methanol at a ratio of 10% by weight. To 100 cc of this alcohol dispersion, 4 g of boron nitride flat powder was mixed. In the same manner as in Example 1, this mixture was repeatedly rotated and rocked to prepare a mixture. This mixture was filled into a beaker, and 20 kHz ultrasonic vibration was applied to the beaker for 1 minute in the same manner as in Example 1. After that, the mixture was filled into a long and narrow strip-like container used in Example 1, and this container was placed on a shaking table of a small shaker, and the container was vibrated under the same conditions as in Example 1. Thereafter, the container was placed in a heat treatment furnace in an air atmosphere and heat treated under the same conditions as in Example 1. In addition, since methanol and benzoic acid have different boiling points, vaporized methanol and benzoic acid were individually recovered by a recovery machine. Thereafter, a load corresponding to 2 kg was applied to the surface of the sample. Further, when the resistance of the sample was measured with an insulation resistance meter, the needle was shaken out and the resistance value was larger than 100 MΩ.
Thereafter, as in Example 1, the sample was placed on a copper plate having the same width as the sample, a load corresponding to 3 kg was applied to the surface of the sample, and the sample was pressure-bonded to the copper plate. Since the pressure-bonded sample can withstand a tensile force of 600 g, it has a sufficient adhesion force of the insulating layer to the conductor surface.
Thereafter, the surface of the sample used in the peel test was observed and analyzed with an electron microscope in the same manner as in Example 1. Furthermore, the sample was cut in the width direction at the center of the sample, and the cross section was observed and analyzed with an electron microscope.
The surface of the sample was covered with 40-60 nm particulates of aluminum oxide. From the observation of the cross section of the sample, the thickness of the sample was 3.2 μm, and the flat surfaces formed three layers through the collection of aluminum oxide fine particles, and the flat surfaces overlapped and joined to form a sample.
In addition, the theoretical value of the insulation resistance formed by the prepared sample is similar to that of Example 1, ignoring the presence of a small amount of aluminum oxide fine particles that fill the gap between adjacent flat powders in the same flat flat layer. When the aluminum oxide layer having a thickness of 0.3 μm forms four layers, the boron nitride layer forms three layers, and these insulating layers are alternately stacked and connected in parallel to form an electrical resistance, the resistance of the insulating film is 3.1 × 10 ¹⁸ Ω. Compared with Example 1, since the electrical resistivity of boron nitride is two orders of magnitude smaller than that of E glass and close to that of aluminum oxide, the resistance value of the boron nitride insulating layer is less than that of aluminum oxide. It approaches the resistance value of the layer. For this reason, the insulation resistance of the insulating film is determined by the insulation resistance formed by the two.

ガラスの扁平粉と窒化ホウ素の扁平粉を用いて、絶縁膜を製造する２つの実施例を説明した。絶縁膜を構成する絶縁性扁平粉は、これら２種類の扁平粉に制限されず、１０段落に説明した他の材質からなる絶縁性扁平粉を用いることができる。また、絶縁膜の形状は、２つの実施例の短冊状の絶縁膜に制限されず、アルコール分散液と絶縁性扁平粉との混合物を充填する容器に応じて、自在に変えることができる。 Two examples of manufacturing an insulating film using flat glass powder and flat boron nitride powder have been described. The insulating flat powder constituting the insulating film is not limited to these two types of flat powder, and insulating flat powder made of other materials described in the 10th paragraph can be used. The shape of the insulating film is not limited to the strip-shaped insulating film of the two embodiments, and can be freely changed according to the container filled with the mixture of the alcohol dispersion and the insulating flat powder.

１酸化アルミニウム微粒子２ガラス扁平粉
1 Aluminum oxide fine particles 2 Glass flat powder

次の５つの要件を満たす絶縁膜は汎用的な絶縁膜になる。本発明の課題は、これら５つの要件を満たす絶縁膜を製造する製造方法を実現することにある。
第一に、安価な材料を用い、極めて簡単な処理で絶縁膜が形成できる。これによって、安価な費用で絶縁膜が製造できる。
第二に、製造する絶縁膜の表面積と形状との各々が自在に変えられる。これによって、用途に応じた表面積と形状とからなる絶縁層が導体に形成できる。
第三に、絶縁膜の圧着によって導体の表面に絶縁層が形成できる。従って、熱処理を伴わずに導体に絶縁層が形成でき、耐熱性の低い部品や基材の導体に絶縁層が形成できる。
第四に、少量の絶縁材料を用いて、３μｍ前後の厚みの絶縁層が形成できる。これによって、安価な費用で極めて大きな絶縁抵抗からなる絶縁膜が形成できる。
第五に、絶縁抵抗が１０^１８Ωに及ぶ値を持つ。従って、絶縁層に漏れ電流が流れず、絶縁層が発熱しないため、導体に接合された部品は、長期にわたって熱劣化しない。 An insulating film that satisfies the following five requirements is a general-purpose insulating film. An object of the present invention is to realize a manufacturing method for manufacturing an insulating film that satisfies these five requirements.
First, an insulating film can be formed by an extremely simple process using an inexpensive material. Thereby, an insulating film can be manufactured at low cost.
Second, the surface area and shape of the insulating film to be manufactured can be freely changed. Thereby, an insulating layer having a surface area and a shape corresponding to the application can be formed on the conductor.
Third, an insulating layer can be formed on the surface of the conductor by pressure bonding of the insulating film. Therefore, an insulating layer can be formed on a conductor without heat treatment, and an insulating layer can be formed on a conductor of a component or substrate having low heat resistance.
Fourth, an insulating layer having a thickness of about 3 μm can be formed using a small amount of insulating material. As a result, an insulating film having an extremely large insulation resistance can be formed at a low cost.
Fifth, the insulation resistance has a value ranging from 10 ¹⁸ Ω. Accordingly, no leakage current flows through the insulating layer, and the insulating layer does not generate heat, so that the component joined to the conductor is not thermally deteriorated over a long period of time.

本発明の容器の底面に該底面の形状からなる絶縁性扁平紛の扁平面同士が重なり合った該扁平粉の集まりの絶縁膜の製造方法は、１０ ^１４ Ωｃｍの高い抵抗率を持つ第一の性質と、モース硬度が９である高い硬度を持つ第二の性質と、１５００℃を超える高い耐熱性を持つ第三の性質を兼備する酸化アルミニウムを熱分解で析出する金属化合物を、アルコールに分散し、該金属化合物がアルコールに分子状態となって分散されたアルコール分散液を作成する第一の工程と、前記アルコール分散液に絶縁性扁平粉の集まりを混合して混合物を作成する第二の工程と、前記混合物を混合機内で回転及び揺動させる第三の工程と、前記混合物中でホモジナイザー装置を稼働させ、該ホモジナイザー装置の稼働によって、前記混合物に連続して衝撃を発生させ、前記絶縁性扁平紛の扁平面同士の重なり合った部位に衝撃を加え、該扁平面同士が重なり合った部位を分離させ、前記絶縁性扁平紛の全ての扁平面が前記アルコール分散液と接する状態にする第四の工程と、前記混合物を底が浅い容器に充填する第五の工程と、前記容器に左右、前後、上下の３方向の振動を繰り返し加え、前記絶縁性扁平粉の扁平面同士が前記アルコール分散液を介して重なり合った該扁平粉の集まりを、前記容器の底面の全体に形成する第六の工程と、前記容器を前記金属化合物が熱分解する温度に昇温し、該金属化合物を熱分解し、前記酸化アルミニウムからなる粒状の微粒子の集まりが、前記絶縁性扁平粉の集まりの最上部の扁平面と最下部の扁平面と、該扁平粉の扁平面同士の間隙とに析出する第七の工程と、前記容器の底面に形成された前記絶縁性扁平粉の集まりに圧縮応力を加え、前記酸化アルミニウムからなる粒状の微粒子同士の接触部位に摩擦熱を発生させ、該摩擦熱によって、前記粒状の微粒子同士が前記接触部位で接合し、該粒状の微粒子同士の接合によって、前記絶縁性扁平粉の扁平面同士が接合され、該扁平面同士が重なり合って接合された絶縁性扁平粉の集まりからなる絶縁膜が、前記容器の底面に、該容器の形状として形成される第八の工程からなり、これら８つの処理を連続して実施することによって、前記容器の底面に、該底面の形状からなる絶縁性扁平紛の扁平面同士が重なり合った該扁平粉の集まりの絶縁膜が製造される、絶縁膜の製造方法である。 The method for producing an insulating film of a collection of the flat powder in which the flat surfaces of the insulating flat powder having the shape of the bottom surface overlap each other on the bottom surface of the container of the present invention is a first property having a high resistivity of 10 ¹⁴ Ωcm. And a metal compound that precipitates by thermal decomposition aluminum oxide, which has a second property with a high hardness with a Mohs hardness of 9 and a third property with a high heat resistance exceeding 1500 ° C. , is dispersed in alcohol. , A first step of creating an alcohol dispersion in which the metal compound is dispersed in a molecular state in alcohol, and a second step of creating a mixture by mixing a collection of insulating flat powders with the alcohol dispersion When, a third step of rotating and oscillating the mixture in a mixing machine, operate the homogenizer device with said mixture, by operation of the homogenizer device, continuously to the mixture impact Generating and applying an impact to the overlapping portions of the flat surfaces of the insulating flat powder to separate the overlapping portions of the flat surfaces, so that all the flat surfaces of the insulating flat powder are in contact with the alcohol dispersion liquid. a fourth step of the state, and a fifth step of filling the mixture in the bottom shallow container, dependent on the vessel, before and after repeated applying vibration of the upper and lower three directions, the flat surface of the insulating flat powder a collection of該扁flat powder with each other are overlapped via the alcohol dispersion, a sixth step you formed on the entire bottom surface of the container, the container wherein the metal compound is heated to thermally decompose temperature, The metal compound is thermally decomposed, and the collection of particulate fine particles made of the aluminum oxide has a gap between an uppermost flat surface and a lowermost flat surface of the collection of the insulating flat powder and the flat surfaces of the flat powder. seventh factory to be deposited to the door Degree and, a collection compressive stress of the insulating flat powder formed on the bottom surface of the vessel was added, the frictional heat is generated in the contact portion of the fine particles of the particulate comprising the aluminum oxide, by the frictional heat, the particulate From the collection of insulating flat powders, the flat surfaces of the insulating flat powder are bonded to each other at the contact site, the flat surfaces of the insulating flat powder are bonded to each other, and the flat surfaces are bonded to each other. comprising an insulating film, the bottom surface of the container, Ri Do the eighth step that will be formed as the shape of the container, by performing in succession these eight processes, the bottom surface of the container, the shape of the bottom surface An insulating film manufacturing method in which an insulating film made of a collection of flat powders in which flat surfaces of insulating flat powders are overlapped with each other is manufactured.

つまり、本製造方法に依れば、極めて簡単な８つの処理を連続して実施すると、安価な製造費で容器の底面に絶縁膜が形成される。この絶縁膜の表面積と形状とは、容器の底面形状になる。このため、絶縁膜の用途に応じて、製造する絶縁膜の表面積と形状とが自在に変えられる。
すなわち、本製造方法が次の４つの特徴を持つことによって、製造された絶縁膜に画期的な作用効果がもたらされる。
第一に、混合物を充填する容器の形状に制約がない。このため、製造される絶縁膜の表面積は、混合物を充填する容器の形状に応じて変わる。例えば、１ｍｍ^２のスポット的な微小膜から１００ｍｍ^２を超える細長い短冊状の絶縁膜に至るまで、製造できる絶縁膜の形状の制約がない。
第二に、金属化合物のアルコール分散液の粘度はアルコールの粘度に近く、また、固体の扁平粉をアルコール分散液に混合しても、混合物の粘度が増大しない。従って、アルコール分散液に扁平粉を混合した混合物を容器に充填し、容器に３方向の振動を加えると、扁平粉の扁平面が重力方向に向けて容器の底面全体に分散し、扁平面同士が重なり合う。例えば、扁平粉の扁平面同士が３重に重なり合うように、容器の底面に扁平粉を配列させると、酸化アルミニウム微粒子の集まりが４層を形成し、扁平面の層が３層を形成し、両者が交互に重なり合って絶縁膜を形成する。この絶縁膜の絶縁抵抗は、アルミニウム微粒子の集まりからなる４つの絶縁抵抗層と、絶縁性扁平粉からなる３つの絶縁抵抗層とが、順番に重なり合って並列接続した絶縁抵抗を構成する。従って、抵抗率が１０^１４Ωｃｍの扁平粉を用いると、厚みが３μｍで幅が１ｃｍで長さが１０ｃｍの絶縁層では、３×１０^１８Ωの絶縁抵抗になる。つまり、抵抗率が大きい２種類の絶縁材料からなる絶縁層の各々が、１μｍより薄い厚みで積み重なり合って絶縁層を形成し、これらの絶縁層が並列接続して絶縁抵抗を構成するため、絶縁膜の絶縁抵抗は極めて大きな値になる。
第三に、混合物を充填する容器の形状に制約がない。このため、絶縁膜の形状は、円、楕円、多角形に限らず、用途に応じて様々な形状の絶縁膜が製造できる。
第四に、金属化合物が熱分解すると、扁平面同士の間隙と絶縁膜の表面に、４０−６０ｎｍの大きさの粒状の酸化アルミニウム微粒子の集まりが析出する。次に、容器の底面に形成された絶縁膜の表面に圧縮応力を加えると、酸化アルミニウムはモース硬度が９の極めて硬い物質であり、酸化アルミニウム微粒子同士が互いに接触する僅かな面積からなる接触部位に、過大な摩擦熱が集中して発生し、酸化アルミニウム微粒子が破壊されずに、摩擦熱によって酸化アルミニウム微粒子同士が接触部位で接合し、一定の機械的強度を持つ絶縁膜が容器の底面に形成される。従って、製造された絶縁膜の表面に、４０−６０ｎｍの大きさの粒状の酸化アルミニウム微粒子の集まりが存在する。この酸化アルミニウム微粒子の集まりは、絶縁膜を部品や基材の導体に圧着する手段になる。このため、部品や基材の導体に絶縁膜を形成する際の熱処理が一切不要になり、耐熱性が低い部品や基材の導体にも絶縁膜が形成できる。
ここで、本製造方法を見出すに至る過程を説明する。絶縁性扁平粉は、長径と短径との平均値と厚さとの比率であるアスペクト比が大きい扁平面を有する。さらに、扁平面の大きさと厚みとにバラツキがある。このような扁平粉の集まりにおいては、扁平面同士が容易に重なり合う。扁平面同士が重なり合った扁平粉を接合した絶縁膜は、扁平面同士が重なり合った部位で破壊する。従って、扁平面同士が重なり合った部位を、分離させることが必要になる。いっぽう、大気中で扁平面の重なり合った部位を分離しようとすると、重なり合った部位に摩擦力が発生するため、分離は容易でない。しかしながら、粘度が低い液体に扁平粉の集まりを混合し、この液体内に衝撃を発生させると、衝撃が扁平面同士の重なり合った部位に伝わり、重なり合った部位が容易に分離する。このため、粘度の低い液体中で、扁平粉の集まりを処理することが必須になる。
さらに、扁平面同士で扁平粉が接合できれば、少量の扁平粉で広い表面積を持つ絶縁膜が形成できる。さらに、少量の扁平粉の集まりを容器の底面全体に分散させ、扁平面同士で重なり合うように配列させると、厚みが極めて薄い絶縁膜が容器の底面に形成され、この絶縁膜は大きな絶縁抵抗を持つ。例えば、扁平面同士が３重に重なり合うように配列させると、３μｍ前後の厚みの絶縁膜が形成でき、絶縁抵抗は絶縁膜の断面積に反比例するため、絶縁抵抗が極めて大きい。従って、扁平粉の集まりを容器の底面全体に分散させ、扁平粉の扁平面同士が重なり合うように配列させる処理が必要になる。
いっぽう、扁平面が一定の面積を持つため、扁平面同士の接合で形成された絶縁膜は、接合面が一定の面積を持つため、一定の機械的強度を持つ。従って、扁平粉の扁平面同士が重なり合うように、扁平粉を配列させる処理が必要になる。ところで、容器に充填された液体中で、扁平粉の集まりに３方向の振動を加えると、扁平面が重力方向に向いて液体中を移動し、重力方向に向いた扁平面の配列が繰り返され、振動を停止すると、扁平面同士が液体を介して重なり合う。このため、扁平粉の集まりを液体に混合し、この混合物を容器に充填し、容器に振動を加える処理が必要になる。
さらに、絶縁性扁平粉は、扁平面の長径と短径との平均値と厚みとにバラツキがある。こうした扁平粉を原料に用い、絶縁膜を製造する。しかしながら、扁平面同士を接合する物質が、扁平面より２桁以上小さい数十ナノの微粒子であれば、微粒子の集まりが扁平面に確実に析出する。また、面積が広い扁平面に優先して微粒子が析出する。さらに、扁平面の大きさにバラツキがあっても、扁平面が微粒子の大きさより２桁以上大きいため、扁平面に微粒子が確実に析出する。さらに、微粒子が粒状であれば、微粒子の集まりが析出する際に、微粒子同士が極狭い接触面積からなる接触部位で接触する。さらに、微粒子の硬度が高ければ、微粒子の集まりに圧縮応力を加えると、微粒子が破壊することなく、微粒子同士の接触部位に摩擦熱が集中して発生し、この摩擦熱で微粒子同士接合する。扁平面同士を接合する手段は、扁平面に硬度の高い粒状の微粒子の集まりを析出させ、微粒子の集まりに圧縮応力を加え、微粒子同士を摩擦熱で接合することを介して、扁平面同士を接合させる手段が有効になる。こうした微粒子を構成する物質として、１０^１４Ωｃｍの高い抵抗率と、モース硬度が９である高い硬度と、摩擦熱で変質しない１５００℃を超える高い耐熱性を持つ、酸化アルミニウム（アルミナとも言う）がある。
従って、絶縁膜を製造する製造方法は、第一に、酸化アルミニウム微粒子の原料を液相化し、この液体に少量の扁平粉を混合し混合物を作成する。第二に、扁平面同士が重なり合った部位を液体中で分離する。この結果、全ての扁平粉は液体と接する。第三に、混合物を容器に充填する。第四に、少量の扁平粉が容器の底面の全体にわたって分散し、扁平面同士が互いに重なり合う処理を行う。このため、容器に３方向の振動を繰り返し加え、容器の底面の全体に扁平粉を分散させ、扁平面同士が重なり合う処理を行う。第五に、容器を昇温し、酸化アルミニウム微粒子の原料を熱分解し、酸化アルミニウム微粒子の集まりを析出させる。つまり、熱分解によって酸化アルミニウムを析出させる手段が、最も簡便である。これによって、扁平粉の扁平面同士の間隙と絶縁膜の表面とに、４０−６０ｎｍの大きさの粒状の酸化アルミニウム微粒子の集まりが析出する。最後に、容器の底面に形成された絶縁膜の表面に圧縮応力を加えると、酸化アルミニウム微粒子同士が接触する部位に、過大な摩擦熱が集中して発生し、この摩擦熱で酸化アルミニウム微粒子同士が接合し、一定の機械的強度を持つ絶縁膜が容器の底面に製造される。なお、絶縁膜に加えた圧縮応力によって、扁平粉が破断したとしても、破断した扁平粉同士が、抵抗体の並列接続を形成するため、破断した扁平粉の絶縁抵抗は低下しない。また、破断した扁平粉は、接合した酸化アルミニウム微粒子の集まりで覆われているため、絶縁膜から離脱しない。
こうした考えに基づき、７段落に記載した８つの処理を連続して実施することで、形状と表面積とが自在に変えられる絶縁膜を製造する製造方法を見出した。
第一工程は、酸化アルミニウムが熱分解で析出する金属化合物を、アルコールの重量に対して１０重量％程度の割合で分散させ、アルコール分散液を作成する。これによって、金属化合物が液相化され、アルコールの粘度に近いアルコール分散液が作成される。つまり、金属化合物がアルコールに分子状態となって分散されるため、このアルコール分散液の粘度はアルコールの粘度に近い。なお、金属化合物は、汎用的な有機酸がアルミニウムと反応して合成された有機酸アルミニウム化合物で、汎用的な工業用薬品である。
第二の工程は、アルコール分散液に少量の扁平粉を混合して混合物を作成する。
第三の工程は、混合物を混合機内で回転及び揺動させる。これによって、扁平粉の集まりが、アルコール分散液中でランダムに混合される。しかし、混合機による回転と揺動だけでは、少量の扁平粉であっても、扁平粉が軽量であるため、扁平面同士が重なり合った部位が確実に分離しない。
第四の工程は、ホモジナイザー装置の稼働によって、混合物に連続して衝撃を発生させる。これによって、扁平面同士の重なり合った部位に衝撃が加わり、重なり合った部位が確実分離され、全ての扁平面が液体と接する状態になり、再度扁平面同士が重なり合うことはない。なお、ホモジナイザー装置として、超音波方式のホモジナイザー装置を用いると、扁平粉の扁平面よりさらに２桁以上小さい莫大な数の気泡の発生と気泡の消滅とが、混合物中で繰り返され（この現象をキャビテーションという）、気泡がはじける際の衝撃波が混合物の全体に繰り返し発生し、液体中では重なり合った扁平面に摩擦力が発生しないため、短時間で扁平面同士の重なった部位が、加えられた衝撃波によって分離する。
第五の工程は、処理した混合物を、底が浅い容器に充填する。
第六の工程は、容器に左右、前後、上下の３方向の振動を加える。この際、低粘度のアルコール分散液と接している扁平粉は、扁平面を重力方向に向けて液体中を移動し、容器の底面の全体に扁平粉の集まりが分散するとともに、扁平面同士の間隙に、扁平面が小さい扁平粉が入り込む配列と、アルコール分散液を介して扁平面同士が重なり合う配列が、液体中で繰り返される。最後に、上下方向の振動を加え、容器への加振を停止すると、扁平面同士がアルコール分散液を介して重なり合った扁平粉の集まりが、容器の底面の全体に形成される。なお、容器に加える振動加速度は、軽量の扁平粉を液体中で移動させるため、０．５Ｇより小さい。
第七の工程は、容器を前記金属化合物が熱分解する温度に昇温する。この際、扁平面同士の間隙を埋めて、酸化アルミニウム微粒子の集まりが析出し、また、表面の扁平面が酸化アルミニウム微粒子で覆われる。
第八の工程は、容器の底面にある絶縁膜の表面に圧縮応力を加える。この際、酸化アルミニウム微粒子同士が互いに接触する極僅かな面積からなる接触部位に、過大な摩擦熱が集中して発生し、この摩擦熱で酸化アルミニウム微粒子同士が接合し、これによって、扁平粉同士が接合され、一定の機械的強度を持つ絶縁膜が容器の底面に製造される。
この絶縁膜は容器の底面の形状からなる。また、絶縁膜の表面に、粒状の酸化アルミニウム微粒子の集まりが存在する。従って、部品や基材の導体の表面に絶縁膜を配置し、絶縁膜に圧縮応力を加えると、部品や基材の導体の表面に酸化アルミニウム微粒子の集まりが食い込み、絶縁膜が部品や基材と一体化される。
ここで、金属化合物が熱分解する際の現象を、昇温温度に即して説明する。最初にアルコールが気化し、これによって、金属化合物の微細結晶の集まりが析出し、極薄い被膜となって、重なり合った扁平面同士の間隙を埋め、また、最上部と最下部の扁平面を、金属化合物の微細結晶の集まりが覆う。次に、金属化合物が熱分解を始める温度に達すると、金属化合物が有機酸と酸化アルミニウムとに分解する。有機酸の密度が酸化アルミニウムの密度より小さいため、有機酸が上層に、酸化アルミニウムが下層に析出し、上層の有機酸が気化熱を奪って気化した後に、４０−６０ｎｍの粒状の酸化アルミニウム微粒子の集まりが、扁平面同士の間隙を埋めて析出し、また、最上部と最下部の扁平面に析出する。
この後、容器の底面に形成された絶縁膜に、圧縮応力を加える。いっぽう、酸化アルミニウム微粒子が粒状微粒子であるため、酸化アルミニウム微粒子同士は、極微小な接触面積で互いに接触する。この酸化アルミニウム微粒子の集まりに圧縮応力が加わると、酸化アルミニウムが極めて硬い物質であるため、酸化アルミニウム微粒子が破壊されることなく、極微小な接触部位に過大な摩擦熱が集中する。このため、酸化アルミニウム微粒子同士が、接触部位で互いに接合する。いっぽう、扁平面と接触する酸化アルミニウム微粒子は、扁平面に応力を加える。扁平面に加わった応力が、扁平面の破断強度より大きくなった際に、応力が加わった部位で扁平粉が破断する。しかし、扁平粉が破断しても、扁平粉が既に接合された酸化アルミニウム微粒子の集まりで覆われているため、破断した扁平粉は絶縁膜から離脱しない。また、扁平粉が破断しても、破断した扁平粉同士が接触し、破断した扁平粉が、抵抗体の並列接続を形成するため、扁平粉の絶縁抵抗は低下しない。この結果、接合した酸化アルミニウム微粒子が、全ての扁平粉を覆うとともに、酸化アルミニウム微粒子の接合によって扁平面が接合され、容器の底面に絶縁膜が形成される。
こうにして製造された絶縁膜は、次の性質を持つ。第一に、絶縁膜の表面は４０−６０ｎｍの酸化アルミニウム微粒子の集まりで覆われ、表面は鏡面研磨より１桁小さい表面粗さを持ち、表面は撥水性、防汚性の性質を持つ。第二に、絶縁膜の表面を形成する酸化アルミニウム微粒子の集まりは、絶縁膜を部品や基材の導体の表面に圧着する手段になる。このため、熱処理を伴わず、耐熱性が低い部品や基材の導体に絶縁層が形成できる。第三に、絶縁膜が、極めて安定な物質である酸化アルミニウム微粒子で覆われ、絶縁膜は継時変化しない。第四に、１０^１８Ωに及ぶ絶縁抵抗を持つ絶縁膜を製造することができる。
ここで、本絶縁膜の製造方法を、６段落に記載した５つの課題に即して説明する。
第一に、安価な材料を用い、極めて簡単な８つの処理を連続して実施することで絶縁膜が形成できる。これによって、安価な費用で絶縁膜が製造できる。
第二に、絶縁膜の表面積と形状とが、容器の底面形状によって自在に変わる。従って、用途に応じた絶縁層が導体に形成できる。
第三に、接触部位で互いに接合した酸化アルミニウム微粒子の集まりが、絶縁膜の表面を覆うため、絶縁膜を導体に圧着することで、導体の表面に絶縁層が形成できる。
第四に、少量の扁平粉を、容器の底面の全体にわたって扁平面同士が互いに重なり合うように配列させることができる。例えば、扁平面同士が３重に重なり合った絶縁膜では、３μｍ前後の厚みの絶縁層が容器の底面に形成される。
第五に、３μｍの厚みからなる絶縁膜は、抵抗率が１０^１４Ωｃｍの扁平粉を用い、幅が１ｃｍで長さが１０ｃｍの絶縁膜では、絶縁抵抗が３×１０^１８Ωになる。
この結果、５つの課題の全てが解決された。 That is, according to this manufacturing method, when eight extremely simple processes are continuously performed, an insulating film is formed on the bottom surface of the container at a low manufacturing cost. The surface area and shape of the insulating film is the shape of the bottom surface of the container. For this reason, according to the use of an insulating film, the surface area and shape of the insulating film to be manufactured can be freely changed.
That is, this manufacturing method has the following four characteristics, and thus, the manufactured insulating film has an epoch-making effect.
First, there is no restriction on the shape of the container filled with the mixture. For this reason, the surface area of the manufactured insulating film changes according to the shape of the container filled with the mixture. For example, the spot micro film of 1 mm ² up to the elongated strip-shaped insulating film exceeding 100 mm ^2, there is no form of limitation of the insulating film can be produced.
Secondly, the viscosity of the alcohol dispersion of the metal compound is close to the viscosity of the alcohol, and even if a solid flat powder is mixed with the alcohol dispersion, the viscosity of the mixture does not increase. Therefore, when a container is filled with a mixture of flat powder mixed with an alcohol dispersion, and the container is subjected to vibration in three directions, the flat surface of the flat powder is dispersed over the entire bottom surface of the container in the direction of gravity. Overlap. For example, when the flat powders are arranged on the bottom surface of the container so that the flat surfaces of the flat powders are overlapped in a triple manner, a collection of aluminum oxide fine particles forms four layers, and the flat surface layers form three layers, Both layers are alternately overlapped to form an insulating film. The insulation resistance of this insulation film constitutes an insulation resistance in which four insulation resistance layers made of a collection of aluminum fine particles and three insulation resistance layers made of insulating flat powder overlap in order and are connected in parallel. Therefore, when a flat powder having a resistivity of 10 ¹⁴ Ωcm is used, an insulating layer having a thickness of 3 μm, a width of 1 cm, and a length of 10 cm has an insulation resistance of 3 × 10 ¹⁸ Ω. In other words, each of the insulating layers made of two types of insulating materials having a high resistivity is stacked with a thickness of less than 1 μm to form an insulating layer, and these insulating layers are connected in parallel to form an insulating resistance. The insulation resistance of the film is extremely large.
Third, there is no restriction on the shape of the container filled with the mixture. For this reason, the shape of the insulating film is not limited to a circle, an ellipse, and a polygon, and various shapes of insulating films can be manufactured depending on the application.
Fourth, when the metal compound is thermally decomposed, a collection of granular aluminum oxide fine particles having a size of 40 to 60 nm is deposited in the gap between the flat surfaces and the surface of the insulating film. Next, when compressive stress is applied to the surface of the insulating film formed on the bottom surface of the container, the aluminum oxide is a very hard substance having a Mohs hardness of 9, and the contact portion consisting of a small area where the aluminum oxide fine particles contact each other In addition, excessive frictional heat is concentrated and the aluminum oxide fine particles are not destroyed, but the aluminum oxide fine particles are bonded to each other by the frictional heat, and an insulating film having a certain mechanical strength is formed on the bottom surface of the container. It is formed. Therefore, a collection of granular aluminum oxide fine particles having a size of 40-60 nm exists on the surface of the manufactured insulating film. This collection of aluminum oxide fine particles serves as a means for pressure-bonding the insulating film to the conductor of the component or the substrate. For this reason, no heat treatment is required when forming an insulating film on a component or base material conductor, and an insulating film can be formed on a component or base material conductor having low heat resistance.
Here, the process leading to finding the present manufacturing method will be described. The insulating flat powder has a flat surface having a large aspect ratio, which is a ratio between the average value of the major axis and the minor axis and the thickness. Furthermore, there is variation in the size and thickness of the flat surface. In such a collection of flat powders, the flat surfaces easily overlap each other. The insulating film joined with the flat powder in which the flat surfaces overlap is broken at the portion where the flat surfaces overlap. Accordingly, it is necessary to separate the portions where the flat surfaces overlap each other. On the other hand, if an attempt is made to separate overlapping portions of flat surfaces in the atmosphere, separation is not easy because frictional force is generated in the overlapping portions. However, when a collection of flat powders is mixed in a liquid having low viscosity and an impact is generated in the liquid, the impact is transmitted to the overlapping portions of the flat surfaces, and the overlapping portions are easily separated. For this reason, it is essential to process a collection of flat powders in a low-viscosity liquid.
Furthermore, if the flat powder can be joined between flat surfaces, an insulating film having a large surface area can be formed with a small amount of flat powder. Furthermore, when a small amount of flat powder is dispersed over the entire bottom surface of the container and arranged so that the flat surfaces overlap each other, an extremely thin insulating film is formed on the bottom surface of the container, and this insulating film has a large insulation resistance. Have. For example, when the flat surfaces are arranged so as to overlap each other in a triple manner, an insulating film having a thickness of about 3 μm can be formed, and the insulating resistance is inversely proportional to the cross-sectional area of the insulating film, so that the insulating resistance is extremely large. Therefore, it is necessary to disperse the collection of flat powder over the entire bottom surface of the container and arrange the flat powder so that the flat surfaces overlap each other.
On the other hand, since the flat surfaces have a certain area, an insulating film formed by bonding flat surfaces has a certain mechanical strength because the bonding surfaces have a certain area. Therefore, the process which arrange | positions flat powder is needed so that the flat surfaces of flat powder may overlap. By the way, when vibrations in three directions are applied to a collection of flat powder in the liquid filled in the container, the flat surface moves in the liquid in the direction of gravity, and the arrangement of the flat surfaces in the direction of gravity is repeated. When the vibration is stopped, the flat surfaces overlap with each other through the liquid. For this reason, the process which mixes the collection of flat powder with a liquid, fills this mixture with a container, and applies a vibration to a container is needed.
Furthermore, the insulating flat powder has variations in the average value and thickness of the major axis and minor axis of the flat surface. An insulating film is manufactured using such flat powder as a raw material. However, if the substance that joins the flat surfaces is a fine particle of several tens of nanometers that is two orders of magnitude or more smaller than the flat surfaces, a collection of fine particles is surely deposited on the flat surfaces. In addition, fine particles are deposited in preference to a flat surface having a large area. Furthermore, even if there is variation in the size of the flat surface, since the flat surface is two orders of magnitude larger than the size of the fine particles, the fine particles are surely deposited on the flat surface. Further, if the fine particles are granular, the fine particles come into contact with each other at a contact portion having a very narrow contact area when the collection of fine particles is precipitated. Furthermore, if the hardness of the fine particles is high, when compressive stress is applied to the collection of fine particles, the fine particles are not destroyed, and frictional heat is concentrated at the contact portion between the fine particles, and the fine particles are joined by this frictional heat. The means for joining flat surfaces to each other is formed by depositing a collection of granular particles having high hardness on the flat surfaces, applying compressive stress to the collection of fine particles, and joining the fine particles with each other by frictional heat. The means to join becomes effective. As a substance constituting such fine particles, aluminum oxide (also referred to as alumina) having a high resistivity of 10 ¹⁴ Ωcm, a high hardness of Mohs hardness of 9, and a high heat resistance exceeding 1500 ° C. which does not change due to frictional heat. is there.
Therefore, in the manufacturing method for manufacturing the insulating film, first, the raw material of the aluminum oxide fine particles is made into a liquid phase, and a small amount of flat powder is mixed with this liquid to create a mixture. Second, the portion where the flat surfaces overlap is separated in the liquid. As a result, all the flat powder comes into contact with the liquid. Third, the mixture is filled into a container. Fourth, a small amount of flat powder is dispersed over the entire bottom surface of the container, and the flat surfaces overlap each other. For this reason, the vibration of 3 directions is repeatedly applied to a container, flat powder is disperse | distributed to the whole bottom face of a container, and the process which flat surfaces overlap is performed. Fifth, the temperature of the container is raised, the raw material of the aluminum oxide fine particles is pyrolyzed, and a collection of aluminum oxide fine particles is precipitated. That is, the means for depositing aluminum oxide by thermal decomposition is the simplest. Thereby, a collection of granular aluminum oxide fine particles having a size of 40 to 60 nm is deposited in the gap between the flat surfaces of the flat powder and the surface of the insulating film. Finally, when compressive stress is applied to the surface of the insulating film formed on the bottom surface of the container, excessive frictional heat is concentrated at the site where the aluminum oxide particles are in contact with each other. And an insulating film having a certain mechanical strength is manufactured on the bottom surface of the container. Even if the flat powder is broken by the compressive stress applied to the insulating film, the broken flat powders form a parallel connection of the resistors, so that the insulation resistance of the broken flat powder does not decrease. Further, the broken flat powder is covered with a collection of bonded aluminum oxide fine particles and thus does not leave the insulating film.
Based on this idea, the inventors have found a manufacturing method for manufacturing an insulating film whose shape and surface area can be freely changed by continuously performing the eight processes described in the seventh paragraph.
In the first step, a metal compound in which aluminum oxide is precipitated by thermal decomposition is dispersed at a ratio of about 10% by weight with respect to the weight of the alcohol to prepare an alcohol dispersion. As a result, the metal compound is converted into a liquid phase and an alcohol dispersion close to the viscosity of the alcohol is produced. That is, since the metal compound is dispersed in a molecular state in the alcohol, the viscosity of the alcohol dispersion is close to that of the alcohol. The metal compound is an organic acid aluminum compound synthesized by reacting a general-purpose organic acid with aluminum, and is a general-purpose industrial chemical.
In the second step, a small amount of flat powder is mixed with the alcohol dispersion to create a mixture.
The third step rotates and rocks the mixture in the mixer. As a result, a collection of flat powders is randomly mixed in the alcohol dispersion. However, even if only a small amount of flat powder is rotated and swung by the mixer, the flat powder is lightweight, and the portion where the flat surfaces overlap is not reliably separated.
In the fourth step, the mixture is continuously impacted by the operation of the homogenizer device. As a result, an impact is applied to the overlapping portions of the flat surfaces, the overlapping portions are reliably separated, all the flat surfaces are in contact with the liquid, and the flat surfaces do not overlap again. When an ultrasonic homogenizer is used as the homogenizer, the generation of a huge number of bubbles that are two orders of magnitude smaller than the flat surface of the flat powder and the disappearance of the bubbles are repeated in the mixture. This is called cavitation, and the shock wave generated when bubbles are repetitively generated in the entire mixture. In the liquid, frictional force is not generated on the overlapping flat surfaces. Separate by.
In the fifth step, the treated mixture is filled into a shallow container.
In the sixth step, vibrations in three directions, left and right, front and rear, and up and down, are applied to the container. At this time, the flat powder in contact with the low-viscosity alcohol dispersion moves in the liquid with the flat surface directed in the direction of gravity, and the collection of flat powder is dispersed over the entire bottom surface of the container. The arrangement in which the flat powder having a small flat surface enters the gap and the arrangement in which the flat surfaces overlap with each other through the alcohol dispersion are repeated in the liquid. Finally, when vibration in the vertical direction is applied and vibration to the container is stopped, a collection of flat powders in which the flat surfaces overlap with each other through the alcohol dispersion liquid is formed on the entire bottom surface of the container. The vibration acceleration applied to the container is smaller than 0.5 G in order to move the light flat powder in the liquid.
In the seventh step, the container is heated to a temperature at which the metal compound is thermally decomposed. At this time, the gap between the flat surfaces is filled, a collection of aluminum oxide fine particles is deposited, and the flat surface of the surface is covered with the aluminum oxide fine particles.
In the eighth step, compressive stress is applied to the surface of the insulating film on the bottom surface of the container. At this time, excessive frictional heat is concentrated at the contact area consisting of a very small area where the aluminum oxide fine particles are in contact with each other, and the aluminum oxide fine particles are joined by this frictional heat. And an insulating film having a certain mechanical strength is manufactured on the bottom surface of the container.
This insulating film has the shape of the bottom surface of the container. In addition, a collection of granular aluminum oxide fine particles exists on the surface of the insulating film. Therefore, when an insulating film is placed on the surface of a component or base material conductor and a compressive stress is applied to the insulating film, a collection of aluminum oxide particles bites into the surface of the component or base material conductor, and the insulating film becomes a part or base material. And integrated.
Here, the phenomenon when the metal compound is thermally decomposed will be described according to the temperature rise. At first, the alcohol vaporizes, and as a result, a collection of fine crystals of the metal compound precipitates, forming an extremely thin film, filling the gaps between the overlapping flat surfaces, and the top and bottom flat surfaces, Covered by a collection of fine crystals of metal compound. Next, when the metal compound reaches a temperature at which thermal decomposition starts, the metal compound decomposes into an organic acid and aluminum oxide. Since the density of the organic acid is smaller than that of aluminum oxide, the organic acid is deposited on the upper layer, the aluminum oxide is deposited on the lower layer, and the upper layer organic acid is vaporized by removing the heat of vaporization. Are deposited in the gap between the flat surfaces, and also deposited on the uppermost and lowermost flat surfaces.
Thereafter, compressive stress is applied to the insulating film formed on the bottom surface of the container. On the other hand, since the aluminum oxide fine particles are granular fine particles, the aluminum oxide fine particles are in contact with each other with a very small contact area. When compressive stress is applied to the aggregate of the aluminum oxide fine particles, the aluminum oxide is an extremely hard substance, and therefore, the aluminum oxide fine particles are not destroyed, and excessive frictional heat is concentrated on a very small contact portion. For this reason, the aluminum oxide fine particles are bonded to each other at the contact site. On the other hand, the aluminum oxide fine particles in contact with the flat surface apply stress to the flat surface. When the stress applied to the flat surface becomes larger than the breaking strength of the flat surface, the flat powder breaks at the site where the stress is applied. However, even if the flat powder breaks, the flat powder that has already been bonded is covered with a collection of joined aluminum oxide fine particles, so that the broken flat powder does not leave the insulating film. Even if the flat powder breaks, the broken flat powders come into contact with each other, and the broken flat powder forms a parallel connection of the resistors, so that the insulation resistance of the flat powder does not decrease. As a result, the joined aluminum oxide fine particles cover all the flat powder, and the flat surfaces are joined by joining the aluminum oxide fine particles, so that an insulating film is formed on the bottom surface of the container.
The insulating film thus manufactured has the following properties. First, the surface of the insulating film is covered with a collection of aluminum oxide fine particles of 40 to 60 nm, the surface has a surface roughness one order of magnitude smaller than that of mirror polishing, and the surface has water repellency and antifouling properties. Second, the collection of aluminum oxide fine particles forming the surface of the insulating film becomes a means for pressure-bonding the insulating film to the surface of the component or the conductor of the substrate. For this reason, an insulating layer can be formed on a part or a conductor of a substrate having low heat resistance without heat treatment. Third, the insulating film is covered with aluminum oxide fine particles, which is a very stable substance, and the insulating film does not change over time. Fourth, an insulating film having an insulation resistance of 10 ¹⁸ Ω can be manufactured.
Here, the manufacturing method of this insulating film will be described in accordance with the five problems described in the sixth paragraph.
First, an insulating film can be formed by continuously performing eight extremely simple processes using an inexpensive material. Thereby, an insulating film can be manufactured at low cost.
Second, the surface area and shape of the insulating film can be freely changed depending on the shape of the bottom surface of the container. Therefore, an insulating layer according to the application can be formed on the conductor.
Third, since the collection of aluminum oxide fine particles bonded to each other at the contact portion covers the surface of the insulating film, the insulating layer can be formed on the surface of the conductor by pressing the insulating film to the conductor.
Fourth, a small amount of flat powder can be arranged so that the flat surfaces overlap each other over the entire bottom surface of the container. For example, in an insulating film in which the flat surfaces overlap in a triple manner, an insulating layer having a thickness of about 3 μm is formed on the bottom surface of the container.
Fifth, an insulating film having a thickness of 3 μm uses flat powder having a resistivity of 10 ¹⁴ Ωcm, and an insulating film having a width of 1 cm and a length of 10 cm has an insulation resistance of 3 × 10 ¹⁸ Ω.
As a result, all the five problems were solved.

７段落に記載した絶縁膜の製造方法は、前記絶縁性扁平粉が、ガラス、マイカ、アルミナ、シリカまたは窒化ホウ素からなるいずれか1種類の材質の扁平粉であり、該扁平粉を７段落に記載した絶縁性扁平粉として用い、７段落に記載した絶縁膜の製造方法に従って絶縁膜を製造する、７段落に記載した絶縁膜の製造方法である。 Manufacturing method of the insulating film described in paragraph 7, the insulating flat powder, glass, mica, alumina, Ri flat powder Der any one material consisting of silica or boron nitride, a該扁flat powder 7 paragraph The method for producing an insulating film described in the seventh paragraph, wherein the insulating film is produced according to the method for producing an insulating film described in the seventh paragraph.

つまり、こうした扁平粉を構成する絶縁物の電気抵抗率は、いずれも１０^１４Ωｃｍ以上の高い絶縁性を持つ。絶縁膜の絶縁抵抗は、扁平粉の電気抵抗率に比例するため、極めて大きな絶縁抵抗を持つ絶縁膜が製造される。なお、ガラス扁平粉では、ソーダ石灰ガラスのみが１０^１２Ωｃｍの電気抵抗率を持つ。また、絶縁性の扁平粉としてヘマタイト（酸化第二鉄Ｆｅ_２Ｏ_３のアルファ相からなる物質）の扁平粉が存在するが、電気抵抗率は１０^８Ωｃｍと低い。いっぽう、上記の絶縁物のモース硬度は、窒化ホウ素が２で、マイカが２．８−３．０で、ガラスが５で、シリカが７で、いずれもアルミナ（酸化アルミニウムを意味する）の９より低い。従って、８段落で説明したように、容器の底面に形成された絶縁膜を圧縮した際に、硬度が低い絶縁物からなる扁平粉ほど、酸化アルミニウム微粒子による応力で破断する恐れがある。しかし、破断した扁平粉が抵抗の並列接続を形成し、絶縁膜の抵抗は低下しない。また、破断した扁平粉は、接合した酸化アルミニウム微粒子の集まりで覆われ、絶縁膜から離脱しない。
以上に説明したように、ガラス、マイカ、アルミナ、シリカまたは窒化ホウ素からなるいずれか1種類の扁平粉を、７段落に記載した絶縁膜の製造方法における絶縁性扁平粉として用い、７段落に記載した製造方法に従って絶縁膜を製造すると、容器の底面に絶縁抵抗が極めて大きい絶縁膜が製造される。 That is, the electrical resistivity of the insulator constituting such a flat powder has a high insulation property of 10 ¹⁴ Ωcm or more. Since the insulation resistance of the insulation film is proportional to the electrical resistivity of the flat powder, an insulation film having an extremely large insulation resistance is manufactured. In the flat glass powder, only soda-lime glass has an electrical resistivity of 10 ¹² Ωcm. In addition, a flat powder of hematite (a substance composed of an alpha phase of ferric oxide Fe ₂ O ₃ ) exists as an insulating flat powder, but its electrical resistivity is as low as 10 ⁸ Ωcm. On the other hand, the Mohs hardness of the above insulator is 2 for boron nitride, 2.8-3.0 for mica, 5 for glass, 7 for silica, and 9 for alumina (which means aluminum oxide). Lower. Therefore, as described in paragraph 8, when the insulating film formed on the bottom surface of the container is compressed, the flat powder made of an insulator having a lower hardness may be broken by the stress caused by the aluminum oxide fine particles. However, the broken flat powder forms a parallel connection of resistance, and the resistance of the insulating film does not decrease. Further, the broken flat powder is covered with a collection of bonded aluminum oxide fine particles and does not leave the insulating film.
As explained above, any one flat powder made of glass, mica, alumina, silica or boron nitride is used as the insulating flat powder in the method for producing an insulating film described in the seventh paragraph, and is described in the seventh paragraph. When an insulating film is manufactured according to the manufacturing method described above, an insulating film having an extremely high insulation resistance is manufactured on the bottom surface of the container.

７段落に記載した絶縁膜の製造方法は、前記酸化アルミニウムを熱分解で析出する金属化合物が、カプリル酸アルミニウム、安息香酸アルミニウム、ナフテン酸アルミニウムからなるいずれか１種類のカルボン酸アルミニウム化合物であり、該カルボン酸アルミニウム化合物を７段落に記載した熱分解で酸化アルミニウムを析出する金属化合物として用い、７段落に記載した絶縁膜の製造方法に従って絶縁膜を製造する、７段落に記載した絶縁膜の製造方法である。 Manufacturing method of the insulating film described in paragraph 7, the metal compound to deposit the aluminum oxide by thermal decomposition, aluminum caprylate, aluminum benzoate, one type of carboxylic acid aluminum compound der consisting naphthenic aluminum Ri Using the aluminum carboxylate compound as a metal compound for depositing aluminum oxide by pyrolysis described in the seventh paragraph, an insulating film is produced according to the method for producing an insulating film described in the seventh paragraph. It is a manufacturing method.

つまり、こうしたカルボン酸アルミニウム化合物は、熱分解で酸化アルミニウムを析出する。従って、７段落に記載した絶縁膜の製造方法において、酸化アルミニウムを熱分解で析出する金属化合物として、上記のカルボン酸アルミニウム化合物を用い、７段落に記載した製造方法に従って絶縁膜を製造すると、容器の底面に絶縁膜が製造される。いっぽう、酸化アルミニウムは、熱伝導率が４０Ｗ／ｍＫで、金属酸化物の中では優れた熱伝導性を持つ。また、１０^１４Ωｃｍ以上の抵抗率を持つ絶縁体で、化学的に安定な酸化物で耐食性に優れ、モース硬度が９からなる硬い物質で、耐熱温度が１５００℃である。このため、絶縁膜の表面は、電気絶縁性と熱伝導性と耐食性と耐熱性の性質を持つ。従って、絶縁膜の表面は硬く、絶縁膜を部品や基材の導体の表面に配置し、絶縁膜に圧縮応力を加えると、絶縁膜の表面の酸化アルミニウム微粒子が導体の表面に食い込み、絶縁膜が導体に圧着し、導体の表面が絶縁化される。
つまり、カルボン酸のカルボキシル基を構成する酸素イオンが配位子になって、アルミニウムイオンに配位結合するカルボン酸アルミニウム化合物は、熱分解によって酸化アルミニウムを析出する。このため、７段落に記載した絶縁膜の製造方法において、酸化アルミニウムを熱分解で析出する金属化合物として、カルボン酸アルミニウム化合物を用い、７段落に記載した製造方法に従って絶縁膜を製造すると、絶縁膜が容器の底面に製造される。なお、カルボン酸アルミニウム化合物の熱分解温度は、ナフテン酸アルミニウムが３３０℃で熱分解する温度が最も高い。また、カルボン酸アルミニウム化合物の大気雰囲気での熱分解は、窒素雰囲気での熱分解より３０−５０℃低いため、大気雰囲気での熱分解は、熱処理費用が安価で済む。また、これらのカルボン酸アルミニウム化合物は、メタノールに１０重量％近くまで分散する。
すなわち、カルボキシル基を構成する酸素イオンが配位子になって、アルミニウムイオンに近づいて配位結合するカルボン酸アルミニウム化合物は、最も大きいイオンであるアルミニウムイオンに酸素イオンが近づいて配位結合するため、両者の距離は短くなる。このため、アルミニウムイオンに配位結合する酸素イオンが、アルミニウムイオンの反対側で共有結合するイオンとの距離が最も長くなる。こうした分子構造上の特徴を持つカルボン酸アルミニウム化合物は、カルボン酸アルミニウム化合物を構成するカルボン酸の沸点を超えると、カルボキシル基を構成する酸素イオンがアルミニウムイオンの反対側で共有結合するイオンとの結合部が最初に分断され、アルミニウムイオンと酸素イオンとの化合物である酸化アルミニウムとカルボン酸とに分解する。さらに昇温すると、カルボン酸が気化熱を奪って気化し、カルボン酸の気化が完了した時点で、酸化アルミニウムが析出する。こうしたカルボン酸アルミニウム化合物として、酢酸アルミニウム、カプリル酸アルミニウム、安息香酸アルミニウム、ナフテン酸アルミニウムなどがある。
なお、酢酸アルミニウムは、熱分解でアモルファス化した酸化アルミニウムを析出し、アモルファス化した酸化アルミニウムの組成は、Ａｌ_２Ｏ_３の組成からずれ、抵抗率は１０^１４Ωｃｍより著しく低い。このため、熱分解で酸化アルミニウムを析出するカルボン酸アルミニウム化合物は、カプリル酸アルミニウム、安息香酸アルミニウム、ナフテン酸アルミニウムからなるいずれか１種類のカルボン酸アルミニウム化合物が望ましい。
また、前記したカルボン酸アルミニウム化合物は、いずれも容易に合成できる安価な工業用薬品である。すなわち、汎用的なカルボン酸を強アルカリと反応させるとカルボン酸アルカリ金属化合物が生成される。この後、カルボン酸アルカリ金属化合物を、無機アルミニウム化合物と反応させると、カルボン酸アルミニウム化合物が合成される。また、原料となるカルボン酸は、有機酸の沸点の中で相対的に低い沸点を有する有機酸であり、大気雰囲気においては３３０℃程度の低い熱処理温度で、酸化アルミニウムが析出する。
以上に説明したように、７段落に記載した絶縁膜の製造方法において、酸化アルミニウムが熱分解で析出する金属化合物として、カプリル酸アルミニウム、安息香酸アルミニウム、ナフテン酸アルミニウムからなるいずれか１種類のカルボン酸アルミニウム化合物を用い、７段落に記載した製造方法に従って絶縁膜を製造すると、絶縁抵抗が大きい絶縁膜が容器の底面に製造される。 That is, such an aluminum carboxylate compound precipitates aluminum oxide by thermal decomposition. Therefore, in the method for manufacturing an insulating film described in the seventh paragraph, when the above-described aluminum carboxylate compound is used as a metal compound for depositing aluminum oxide by thermal decomposition, and the insulating film is manufactured according to the manufacturing method described in the seventh paragraph, An insulating film is manufactured on the bottom surface of the substrate. On the other hand, aluminum oxide has a thermal conductivity of 40 W / mK, and has excellent thermal conductivity among metal oxides. Further, it is an insulator having a resistivity of 10 ¹⁴ Ωcm or more, a chemically stable oxide, excellent in corrosion resistance, a hard substance having a Mohs hardness of 9, and a heat resistant temperature of 1500 ° C. For this reason, the surface of the insulating film has properties of electrical insulation, thermal conductivity, corrosion resistance, and heat resistance. Therefore, the surface of the insulating film is hard, and when the insulating film is placed on the surface of the conductor of the component or the substrate and compressive stress is applied to the insulating film, the aluminum oxide fine particles on the surface of the insulating film bite into the surface of the conductor, Is crimped to the conductor, and the surface of the conductor is insulated.
That is, the oxygen ion constituting the carboxyl group of the carboxylic acid serves as a ligand, and the aluminum carboxylate compound coordinated to the aluminum ion precipitates aluminum oxide by thermal decomposition. For this reason, in the manufacturing method of an insulating film described in the seventh paragraph, when an insulating film is manufactured according to the manufacturing method described in the seventh paragraph using an aluminum carboxylate compound as a metal compound for depositing aluminum oxide by thermal decomposition, the insulating film Is manufactured on the bottom of the container. The thermal decomposition temperature of the aluminum carboxylate compound is the highest at which the aluminum naphthenate thermally decomposes at 330 ° C. In addition, the thermal decomposition of the aluminum carboxylate compound in the air atmosphere is 30-50 ° C. lower than the thermal decomposition in the nitrogen atmosphere, so that the thermal decomposition in the air atmosphere can be inexpensive in heat treatment. These aluminum carboxylate compounds are dispersed in methanol up to nearly 10% by weight.
That is, the oxygen ion constituting the carboxyl group becomes a ligand, and the carboxylate aluminum compound that is coordinated and bonded to the aluminum ion is coordinated and bonded to the aluminum ion that is the largest ion. The distance between the two becomes shorter. For this reason, the distance between the oxygen ion coordinated to the aluminum ion and the ion covalently bonded on the opposite side of the aluminum ion is the longest. When the carboxylate aluminum compound having such molecular structure characteristics exceeds the boiling point of the carboxylic acid constituting the carboxylate aluminum compound, the oxygen ion constituting the carboxyl group is bonded to the ion covalently bonded to the opposite side of the aluminum ion. The part is first divided and decomposed into aluminum oxide and carboxylic acid, which are compounds of aluminum ions and oxygen ions. When the temperature is further raised, the carboxylic acid takes the heat of vaporization and vaporizes, and when the vaporization of the carboxylic acid is completed, aluminum oxide is deposited. Examples of such aluminum carboxylate compounds include aluminum acetate, aluminum caprylate, aluminum benzoate, and aluminum naphthenate.
Note that aluminum acetate precipitates aluminum oxide that has been amorphized by thermal decomposition, and the composition of the amorphized aluminum oxide deviates from the composition of Al ₂ O ₃ and the resistivity is significantly lower than 10 ¹⁴ Ωcm. For this reason, the aluminum carboxylate compound that deposits aluminum oxide by thermal decomposition is preferably any one of aluminum carboxylate compounds composed of aluminum caprylate, aluminum benzoate, and aluminum naphthenate.
In addition, the above-described aluminum carboxylate compound is an inexpensive industrial chemical that can be easily synthesized. That is, when a general-purpose carboxylic acid is reacted with a strong alkali, a carboxylic acid alkali metal compound is produced. Thereafter, when the alkali metal carboxylate compound is reacted with the inorganic aluminum compound, the aluminum carboxylate compound is synthesized. The carboxylic acid as a raw material is an organic acid having a relatively low boiling point among the boiling points of organic acids, and aluminum oxide is deposited at a low heat treatment temperature of about 330 ° C. in the air atmosphere.
As described above, in the method for manufacturing an insulating film described in the seventh paragraph, any one of the carboxyls composed of aluminum caprylate, aluminum benzoate, and aluminum naphthenate is used as the metal compound from which aluminum oxide is deposited by thermal decomposition. When an insulating film is manufactured according to the manufacturing method described in the seventh paragraph using an aluminum acid compound, an insulating film having a large insulation resistance is manufactured on the bottom surface of the container.

実施例１
本実施例では、ガラス扁平粉を酸化アルミニウム微粒子の集まりで接合して絶縁膜を製造する。ガラス扁平粉（日本板硝子株式会社のＭＥＧ−１６０）は、鱗片形状で無アルカリガラス（Ｅガラスとも言う）からなり、抵抗率が１０^１６Ωｃｍで、軟化点が８４０℃で、平均厚みが０．７μｍで、平均粒径が１６０μｍである。また、酸化アルミニウム微粒子の原料は、熱分解温度が３１０℃の安息香酸アルミニウムＡｌ（Ｃ_６Ｈ_５ＣＯＯ）_３（三津和化学薬品株式会社の製品）を用いた。
最初に、安息香酸アルミニウムを１０重量％の割合でメタノールに分散させた。このアルコール分散液の１００ｃｃに、３ｇのガラス扁平粉を混合した。この混合物を、回転による拡散混合と揺動による移動混合とを同時に行う装置（愛知電機株式会社のロッキングミキサーＲＭＨ−ＨＴ）に充填し、回転と揺動を繰り返して混合物を作成した。この混合物をビーカーに充填し、超音波ホモジナイザー装置（ヤマト科学株式会社の製品ＬＵＨ３００）によって、２０ｋＨｚの超音波振動をビーカーに１分間加えた。この後、混合物を１０ｍｍ×１００ｍｍ×５ｍｍの細長い短冊状の容器に充填し、この容器を小型加振機の加振台の上に載せ、左右、前後、上下の３方向に、０．３Ｇの振動加速度を５秒間ずつ３回繰り返し、最後に、上下方向に０．３Ｇの振動加速度を１０秒間加えた。この後、容器を大気雰囲気の熱処理炉に入れ、メタノールを気化させた後に、３１０℃で２分間熱処理し、短冊状の厚みが極薄い試料を容器の底面に作成した。なお、メタノールと安息香酸とは沸点が異なるため、気化したメタノールと安息香酸とは、回収機で個別に回収した。この後、試料の表面に３ｋｇに相当する荷重を加えた。さらに、絶縁抵抗計で試料の抵抗を測定したところ、針が振り切れ、抵抗値は１００ＭΩより大きい値であった。
この後、試料を試料と同じ幅の銅板の上に配置し、試料の表面に５ｋｇに相当する荷重を加え、銅板に圧着させた。圧着した試料を、ＪＩＳＫ６８５４−１の剥離接着強さ試験方法による剥離試験で、試料は８００ｇ重の引っ張り力に耐えられたため、絶縁層は、導体表面に対し十分な密着力を持つ。
この後、剥離試験に用いた試料の表面を電子顕微鏡で観察と分析を行なった。さらに、試料の中央部で幅方向に試料を切断し、断面を電子顕微鏡で観察と分析を行なった。電子顕微鏡は、ＪＦＥテクノリサーチ株式会社の極低加速電圧ＳＥＭを用いた。この装置は、１００Ｖからの極低加速電圧による観察が可能で、試料に導電性の被膜を形成せずに直接試料が観察できる。
最初に、試料の表面からの反射電子線の９００−１０００Ｖの間にある２次電子線を取り出して画像処理を行った。試料の表面は、４０−６０ｎｍの大きさからなる微粒子の集まりで覆われていた。次に、試料の表面からの反射電子線について、９００−１０００Ｖの間にあるエネルギーを抽出して画像処理を行い、画像の濃淡で粒状微粒子の材質を分析した。いずれの粒状微粒子にも濃淡が認められたので、複数原子から構成されていることが分かった。さらに、特性エックス線のエネルギーとその強度を画像処理し、粒子を構成する元素の種類を分析した。アルミニウム原子と酸素原子とで構成されていたため、微粒子は酸化アルミニウム微粒子である。
さらに、試料の断面からの反射電子線の９００−１０００Ｖの間にある２次電子線を取り出して画像処理を行った。試料の厚みは３μｍであり、酸化アルミニウム微粒子の集まりを介して、扁平面が３層をなして扁平面同士で重なり合って接合し、試料を形成していた。図１は、試料の断面の一部を模式的に拡大した図である。１は酸化アルミニウム微粒子で、２はガラス扁平粉である。
なお、作成した試料が形成する絶縁抵抗の理論値は、厚みが０．３μｍの酸化アルミニウム層が４層をなし、ガラス層が３層をなし、これらの絶縁層が交互に積層して並列接続して電気抵抗を構成すると、絶縁膜の絶縁抵抗は８．１×１０^１８Ωになる。この絶縁膜の抵抗値は、２種類の絶縁層同士が並列接続するため、相対的に抵抗値が小さい酸化アルミニウムの絶縁層の抵抗値が、絶縁膜の抵抗値に大きく寄与する、つまり、酸化アルミニウムの絶縁層の厚みが、絶縁膜の抵抗値に大きく寄与する。 Example 1
In this embodiment, the glass flat powder is joined with a collection of aluminum oxide fine particles to produce an insulating film. Glass flat powder (MEG-160 from Nippon Sheet Glass Co., Ltd.) is made of scale-free and non-alkali glass (also called E glass), has a resistivity of 10 ¹⁶ Ωcm, a softening point of 840 ° C., and an average thickness of 0.00. The average particle diameter is 7 μm and 160 μm. Moreover, aluminum benzoate Al (C ₆ H ₅ COO) ₃ (product of Mitsuwa Chemicals Co., Ltd.) having a thermal decomposition temperature of 310 ° C. was used as a raw material for the aluminum oxide fine particles.
First, aluminum benzoate was dispersed in methanol at a ratio of 10% by weight. 3 g of glass flat powder was mixed with 100 cc of this alcohol dispersion. This mixture was filled in a device (a rocking mixer RMH-HT manufactured by Aichi Electric Co., Ltd.) that simultaneously performs diffusion mixing by rotation and moving mixing by oscillation, and the mixture was prepared by repeating rotation and oscillation. This mixture was filled in a beaker, and ultrasonic vibration of 20 kHz was applied to the beaker for 1 minute by an ultrasonic homogenizer (product LUH300 manufactured by Yamato Scientific Co., Ltd.). After that, the mixture is filled into a 10 mm × 100 mm × 5 mm elongated strip-shaped container, and this container is placed on a shaking table of a small shaker, and 0.3 G in three directions, left, right, front, back, top and bottom. The vibration acceleration was repeated 3 times for 5 seconds, and finally 0.3 G vibration acceleration was applied for 10 seconds in the vertical direction. Thereafter, the container was placed in a heat treatment furnace in an atmospheric atmosphere to vaporize methanol, and then heat-treated at 310 ° C. for 2 minutes to prepare a sample having a very thin strip shape on the bottom surface of the container. In addition, since methanol and benzoic acid have different boiling points, vaporized methanol and benzoic acid were individually recovered by a recovery machine. Thereafter, a load corresponding to 3 kg was applied to the surface of the sample. Furthermore, when the resistance of the sample was measured with an insulation resistance meter, the needle was shaken out and the resistance value was greater than 100 MΩ.
Thereafter, the sample was placed on a copper plate having the same width as the sample, a load corresponding to 5 kg was applied to the surface of the sample, and the sample was pressure bonded to the copper plate. In the peel test according to the peel adhesion strength test method of JIS K6854-1, the pressure-bonded sample was able to withstand a tensile force of 800 g, so that the insulating layer has sufficient adhesion to the conductor surface.
Thereafter, the surface of the sample used for the peel test was observed and analyzed with an electron microscope. Furthermore, the sample was cut in the width direction at the center of the sample, and the cross section was observed and analyzed with an electron microscope. The electron microscope used was an ultra-low acceleration voltage SEM from JFE Techno-Research Corporation. This apparatus can be observed with an extremely low acceleration voltage from 100 V, and the sample can be directly observed without forming a conductive film on the sample.
First, a secondary electron beam between 900-1000 V of the reflected electron beam from the surface of the sample was taken out and image processing was performed. The surface of the sample was covered with a collection of fine particles having a size of 40-60 nm. Next, with respect to the reflected electron beam from the surface of the sample, energy between 900 and 1000 V was extracted and image processing was performed, and the material of the granular fine particles was analyzed based on the density of the image. Since all the granular fine particles were observed to be shaded, it was found that they were composed of a plurality of atoms. Furthermore, the energy and intensity of characteristic X-rays were image-processed, and the types of elements constituting the particles were analyzed. Since it is composed of aluminum atoms and oxygen atoms, the fine particles are aluminum oxide fine particles.
Furthermore, the secondary electron beam between 900-1000 V of the reflected electron beam from the cross section of the sample was taken out and image processing was performed. The thickness of the sample was 3 μm, and the flat surfaces formed three layers through the collection of aluminum oxide fine particles, and the flat surfaces overlapped and joined to form a sample. FIG. 1 is a schematic enlarged view of a part of a cross section of a sample. 1 is aluminum oxide fine particles, and 2 is glass flat powder.
In addition, the theoretical value of the insulation resistance formed by the prepared sample is 4 layers of aluminum oxide layers with a thickness of 0.3 μm, 3 layers of glass layers, and these insulating layers are alternately stacked and connected in parallel. Thus, when the electric resistance is configured, the insulating resistance of the insulating film is 8.1 × 10 ¹⁸ Ω. The resistance value of this insulating film is that two types of insulating layers are connected in parallel. Therefore, the resistance value of the insulating layer of aluminum oxide having a relatively small resistance value greatly contributes to the resistance value of the insulating film. The thickness of the aluminum insulating layer greatly contributes to the resistance value of the insulating film.

実施例２
本実施例では、窒化ホウ素の扁平粉を、酸化アルミニウム微粒子の集まりで接合して絶縁膜を製造する。窒化ホウ素扁平粉（昭和電工株式会社のＵＨＰ−２）は、鱗片形状の窒化ホウ素粉で、抵抗率が１０^１４Ωｃｍで、平均粒径が１１μｍで、ＢＥＴ比表面積が３−５ｍ^２／ｇである。また、アルミニウム微粒子の原料は、実施例１の安息香酸アルミニウムを用いた。
最初に、安息香酸アルミニウムを１０重量％の割合でメタノールに分散させた。このアルコール分散液の１００ｃｃに、４ｇの窒化ホウ素の扁平粉を混合した。この混合物に、実施例１と同様に、回転と揺動を繰り返して混合物を作成した。この混合物をビーカーに充填し、実施例１と同様に、ビーカーに２０ｋＨｚの超音波振動を１分間加えた。この後、混合物を実施例１で用いた細長い短冊状の容器に充填し、この容器を小型加振機の加振台の上に載せ、実施例１と同じ条件で容器に振動を加えた。この後、容器を大気雰囲気の熱処理炉に入れ、実施例１と同じ条件で熱処理した。なお、メタノールと安息香酸とは沸点が異なるため、気化したメタノールと安息香酸とは、回収機で個別に回収した。この後、試料の表面に２ｋｇに相当する荷重を加えた。また、絶縁抵抗計で試料の抵抗を測定したところ、針が振り切れ、抵抗値は１００ＭΩより大きい値であった。
この後、実施例1と同様に、試料を試料と同じ幅の銅板の上に配置し、試料の表面に３ｋｇに相当する荷重を加え、銅板に圧着させた。圧着した試料は６００ｇ重の引っ張り力に耐えられたため、導体表面への絶縁層の十分な接着力を持つ。
この後、剥離試験に用いた試料の表面を、実施例1と同様に、電子顕微鏡で観察と分析を行なった。さらに、試料の中央部で幅方向に試料を切断し、断面を電子顕微鏡で観察と分析を行なった。
試料の表面は、酸化アルミニウムの４０−６０ｎｍの粒状微粒子で覆われていた。試料の断面の観察から、試料の厚みは３．２μｍであり、酸化アルミニウム微粒子の集まりを介して、扁平面が３層をなして扁平面同士で重なり合って接合し、試料を形成していた。
なお、作成した試料が形成する絶縁抵抗の理論値は、厚みが０．３μｍの酸化アルミニウム層が４層をなし、窒化ホウ素層が３層をなし、これらの絶縁層が交互に積層して並列接続して電気抵抗を構成すると、絶縁膜の抵抗は３．１×１０^１８Ωになる。実施例１と比べると、窒化ホウ素の電気抵抗率が、Ｅガラスの電気抵抗率より２桁小さいため、窒化ホウ素の絶縁層の抵抗値が、酸化アルミニウムの絶縁層の抵抗値に近づく。このため、両者が形成する絶縁抵抗によって、絶縁膜の絶縁抵抗が決まる。 Example 2
In this embodiment, a flat powder of boron nitride is joined with a collection of aluminum oxide fine particles to produce an insulating film. Boron nitride flat powder (UHP-2 from Showa Denko KK) is a scale-shaped boron nitride powder having a resistivity of 10 ¹⁴ Ωcm, an average particle size of 11 μm, and a BET specific surface area of 3-5 m ² / g. is there. Moreover, the aluminum benzoate of Example 1 was used as the raw material for the aluminum fine particles.
First, aluminum benzoate was dispersed in methanol at a ratio of 10% by weight. To 100 cc of this alcohol dispersion, 4 g of boron nitride flat powder was mixed. In the same manner as in Example 1, this mixture was repeatedly rotated and rocked to prepare a mixture. This mixture was filled into a beaker, and 20 kHz ultrasonic vibration was applied to the beaker for 1 minute in the same manner as in Example 1. After that, the mixture was filled into a long and narrow strip-like container used in Example 1, and this container was placed on a shaking table of a small shaker, and the container was vibrated under the same conditions as in Example 1. Thereafter, the container was placed in a heat treatment furnace in an air atmosphere and heat treated under the same conditions as in Example 1. In addition, since methanol and benzoic acid have different boiling points, vaporized methanol and benzoic acid were individually recovered by a recovery machine. Thereafter, a load corresponding to 2 kg was applied to the surface of the sample. Further, when the resistance of the sample was measured with an insulation resistance meter, the needle was shaken out and the resistance value was larger than 100 MΩ.
Thereafter, as in Example 1, the sample was placed on a copper plate having the same width as the sample, a load corresponding to 3 kg was applied to the surface of the sample, and the sample was pressure-bonded to the copper plate. Since the pressure-bonded sample can withstand a tensile force of 600 g, it has a sufficient adhesion force of the insulating layer to the conductor surface.
Thereafter, the surface of the sample used in the peel test was observed and analyzed with an electron microscope in the same manner as in Example 1. Furthermore, the sample was cut in the width direction at the center of the sample, and the cross section was observed and analyzed with an electron microscope.
The surface of the sample was covered with 40-60 nm particulates of aluminum oxide. From the observation of the cross section of the sample, the thickness of the sample was 3.2 μm, and the flat surfaces formed three layers through the collection of aluminum oxide fine particles, and the flat surfaces overlapped and joined to form a sample.
The theoretical value of the insulation resistance formed by the prepared sample is that the aluminum oxide layer having a thickness of 0.3 μm consists of four layers, the boron nitride layer forms three layers, and these insulating layers are alternately stacked in parallel. When connected to form an electrical resistance, the resistance of the insulating film is 3.1 × 10 ¹⁸ Ω. Compared with Example 1, since the electrical resistivity of boron nitride is two orders of magnitude smaller than that of E glass, the resistance value of the insulating layer of boron nitride approaches the resistance value of the insulating layer of aluminum oxide. For this reason, the insulation resistance of the insulating film is determined by the insulation resistance formed by the two.

Claims

The method for producing an insulating film includes a first step in which a metal compound that precipitates aluminum oxide by thermal decomposition is dispersed in alcohol to create an alcohol dispersion, and a mixture of insulating flat powders is mixed into the alcohol dispersion. A second step of preparing the mixture, a third step of rotating and swinging the mixture in a mixer, a fourth step of treating the mixture with a homogenizer device, and placing the mixture in a container having a shallow bottom. A fifth step of filling, a sixth step of repeatedly applying left, right, front, back, top and bottom vibrations to the container; a seventh step of raising the temperature of the container to a temperature at which the metal compound is thermally decomposed; The insulating film having the shape of the bottom surface is formed on the bottom surface of the container by continuously performing these eight processes including the eighth step of applying compressive stress to the insulating film formed on the bottom surface of the container. Manufacturing The manufacturing method of the insulating film.

2. The method for producing an insulating film according to claim 1, wherein the insulating flat powder is a flat powder made of any one material made of glass, mica, alumina, silica, or boron nitride. Method for manufacturing an insulating film.

2. The method of manufacturing an insulating film according to claim 1, wherein the metal compound for depositing the aluminum oxide by pyrolysis is any one aluminum carboxylate compound composed of aluminum caprylate, aluminum benzoate, and aluminum naphthenate. The method for manufacturing an insulating film according to claim 1.