JPH10190196A - Insulating film and its formation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily form an insulating film having a desired thickness, a high resistance, and an excellent insulating property on a substrate by forming the insulating film by applying an insulating material solution containing dispersed insulating particles to the substrate and baking the substrate. SOLUTION: In an applying process, such a case that insulating particles 3 settle immediately after the particles 3 are mixed in a liquid and the liquid is stirred depending upon the grain size of the particles 3 or the component of the liquid. For such a case, it is preferable to stir the solution mechanically or by using ultrasonic waves. In a baking process, preliminary baking is performed before proper baking as necessary after the insulating material solution containing the particles 3 is applied to the substrate. In applying the solution to the substrate, any generally used coating method, such as the spin coating method, dip coating method, spray coating method, coating method using roll bar, etc., can be used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an insulating film provided on a circuit board or the like and a method for forming the same.

[0002]

2. Description of the Related Art Conventionally, when an insulating film is formed on a circuit board, a screen printing method using a glass paste, a CVD method,
, An LPD method, various coating methods using a sol-gel method, and the like.

[0003] In the printing method, for example, a commercially available glass paste (for example, one manufactured by Noritake Co., Ltd.) is applied onto a substrate by a method such as a screen printing method and the like.
A film is formed by firing before and after. The formed insulating film has a thickness of about 20 to 50 μm and a relative dielectric constant of 10 to 30.
About.

In the CVD method, for example, a substrate is placed under a high pressure and an SiO ₂ film having a thickness of about 1 μm is formed by vapor deposition of a silane-based gas or oxidation of silicon by a carrier gas such as argon, helium, or oxygen. I do.

In the LPD method, for example, SiO ₂ is dissolved in an aqueous solution of hydrofluoric acid at a low temperature to form a supersaturated solution, and the substrate is immersed in the solution and heated to about 30 to 40 ° C. to deposit SiO ₂ on the substrate. (Temperature method) or by adding aluminum, water, and boric acid to shift the chemical equilibrium, to deposit SiO ₂ on the substrate to form a film.

In the sol-gel method, for example, a solution of a silicone compound such as ethyltriethoxysilane / ethyltriethoxysilane polymer in ethanol / toluene / ethyl acetate, or a commercially available sol-gel solution (eg, Atron manufactured by Nippon Soda Co., Ltd.) Or Tosgard, manufactured by Toshiba Silicone Co., Ltd.) or a preparation prepared by dissolving a silane compound such as tetraethoxysilane in an appropriate solvent such as ethanol, and applied to the substrate using a technique such as dip, spray or spin coating. Then, the film is formed by firing at about 300 to 500 ° C. The formed insulating film has a thickness of several μm.
To this extent, the relative dielectric constant is about 3 to 15.

On the other hand, as an application of a circuit board on which such an insulating film is formed, there is an image forming apparatus using a surface conduction electron-emitting device. Hereinafter, the surface conduction electron-emitting device will be described.

[0008] As the electron-emitting devices, there are roughly classified two types using a thermionic electron-emitting device and a cold cathode electron-emitting device. Field emission type (hereinafter referred to as "FE")
Type ". ), Metal / insulating layer / metal type (hereinafter “MIM”)
Type ". ), Surface conduction electron-emitting devices, and the like.
The surface conduction electron-emitting device utilizes the phenomenon that electron emission occurs when a current flows in a small-area thin film formed on a substrate in parallel with the film surface. Examples of the surface conduction electron-emitting device include a device using a SnO ₂ thin film by MIElinson and the like and a device using an Au thin film (G. Dittmer, Thin
Solid Films, 9,317 (1972)), using an In ₂ O ₃ / SnO ₂ thin film (M. Hartwell and CGFonstad, IEEE Trans.
ED conf., 519 (1975)), using a carbon thin film (Hisashi Araki et al., Vacuum, Vol. 26, No. 1, p. 22 (198
3)) etc. have been reported.

[0009] A typical device configuration of these surface conduction electron-emitting devices is described in the above-mentioned M. Hartwell.
FIG. 5 schematically shows these element configurations. In the figure, 50
1 is a substrate. Reference numeral 504 denotes a conductive thin film made of a metal oxide thin film or the like formed by sputtering in an H-shaped pattern, and the electron emission portion 505 is formed by an energization process called energization forming. The device electrodes (5
02, 503) is set to 0.5 to 1 mm, and W is set to about 0.1 mm.

Heretofore, in these surface conduction electron-emitting devices, it has been common practice to form the electron-emitting portion 5 on the conductive thin film 4 by an energization process called energization forming before electron emission. . That is, energization forming means applying a DC voltage or a very slowly increasing voltage, for example, about 1 V / min, to both ends of the conductive thin film 4 and energizing the conductive thin film 4 to locally destroy, deform or alter the conductive thin film. The purpose is to form the electron-emitting portion 5 in a state of high resistance. In the electron emitting portion 5, a crack is generated in a portion of the conductive thin film 4, and electrons are emitted from the vicinity of the crack. The surface conduction type electron-emitting device that has been subjected to the energization forming process applies the voltage to the conductive thin film 4 and causes a current to flow through the device, thereby forming the electron-emitting portion 5.
It causes more electrons to be emitted.

The above-described surface conduction electron-emitting device has a simple structure and is easy to manufacture, and thus has an advantage that a large number of devices can be arranged and formed over a large area. Therefore, utilizing this feature, applied researches on charged beam sources, display devices, and the like have been made.

An image forming apparatus using a surface conduction electron-emitting device is disclosed in, for example, Japanese Patent Application Laid-Open No. 2-299136.

[0013]

However, each of the above-mentioned conventional methods for forming an insulating film has the following problems.

That is, in the printing method, since a glass paste is used, only a thick film having a film thickness of several tens of μm or more is formed, and since there are many components such as PdO, the relative dielectric constant is increased, and the insulating properties are deteriorated. There was a disadvantage of becoming.

Further, the CVD method requires a high vacuum, so that it is difficult to increase the area of the substrate, and the throughput is long.
There was a disadvantage.

Further, the LPD method has a drawback that the film forming speed is very slow and the throughput becomes longer in proportion to the film thickness. There is also a disadvantage that an insulating layer can be formed only on SiO ₂ .

In addition, the sol-gel method has a drawback that, even when a thick film is required, the thickness can be increased only from several hundred nm to at most several μm.

Further, in the conventional method, when the substrate and the insulating layer to be formed are made of different materials, stress is generated between the substrate and the insulating layer due to a difference in coefficient of thermal expansion, and cracks and peeling after cooling. There is a disadvantage that warping and the like occur.

An object of the present invention is to provide a method for easily forming an insulating film having a desired thickness, high resistance and good insulating properties on a substrate. Another object of the present invention is to provide an insulating film which has no insulation cracks, cracks, warpage, peeling, etc., has good insulation properties, and has a desired film thickness.

[0020]

Means for Solving the Problems The present inventors have conducted various studies to achieve the above object, and as a result, completed the present invention. The above object is achieved by the present invention described below.

The first invention is a method for forming an insulating film on a substrate, comprising: (1) a step of dispersing insulating particles in an insulating material coating solution; and (2) an insulating material coating solution containing insulating particles. And (3) baking the substrate to form an insulating film.

The second invention relates to the method of forming an insulating film according to the first invention, wherein in the firing of the substrate after the application, the preliminary firing is performed, and then the main firing is performed at a temperature higher than the temporary firing temperature.

The third invention relates to the method of forming an insulating film according to the first invention, wherein the coefficient of linear expansion of the insulating particles is substantially equal to that of the substrate.

According to a fourth aspect of the present invention, the particle size of the insulating particles is 10n.
The present invention relates to a method for forming an insulating film according to the first, second or third aspect of the present invention, which has a thickness of 10 to 10 μm.

According to a fifth aspect of the present invention, there is provided the method according to any one of the first to fourth aspects, wherein the insulating particles are added in the range of 10 to 70% by weight based on the insulating material coating liquid containing the insulating particles. The present invention relates to a method for forming an insulating film.

According to a sixth aspect of the present invention, after the insulating film is formed, the insulating film does not contain insulating particles or is smaller than the minute gap so that the minute gap generated in the insulating film can be filled. The present invention relates to a method for forming an insulating film according to a first aspect of the present invention, in which an insulating material coating solution containing insulating particles is applied and baked.

According to a seventh aspect of the present invention, the insulating particles have a melting point or softening point sufficiently lower than the softening point of the substrate, and the final baking is performed at a temperature higher than the melting point or softening point of the insulating particles. The invention relates to a method for forming an insulating film.

According to an eighth aspect of the present invention, there is provided a method for forming an insulating film according to any one of the first to seventh aspects, wherein an insulating material coating solution containing insulating particles is mechanically stirred and applied until immediately before coating the substrate. About.

A ninth aspect of the present invention is directed to the insulating film according to any one of the first to eighth aspects, wherein an insulating material coating solution containing insulating particles is applied by stirring using an ultrasonic wave until immediately before coating the substrate. It relates to a forming method.

According to a tenth aspect of the present invention, there is provided the insulating film according to any one of the first to ninth aspects, which is formed as an interlayer insulating layer in a method of manufacturing a surface conduction electron-emitting device and an image forming apparatus using the device. It relates to a forming method.

The eleventh invention relates to an insulating film formed by applying an insulating material coating solution containing insulating particles on a substrate and firing the applied solution.

The twelfth invention relates to the insulating film of the eleventh invention, wherein the coefficient of linear expansion of the insulating particles is substantially equal to that of the substrate.

According to a thirteenth aspect, the insulating particles have a particle size of 10
The present invention relates to an insulating film according to an eleventh or twelfth invention having a thickness of 10 nm to 10 μm.

A fourteenth invention is directed to the eleventh, twelfth, or thirteenth invention, wherein the insulating particles are added in an amount of 10 to 70% by weight based on the insulating particle-containing insulating material coating solution. It relates to an insulating film.

According to a fifteenth aspect, an insulating material coating solution containing insulating particles is applied to a substrate and baked so that a minute gap generated in the insulating film can be filled in the insulating film. The present invention relates to an insulating film formed by applying and baking an insulating material coating solution containing no insulating particles or containing insulating particles smaller than the minute gap on a substrate.

The sixteenth invention relates to the insulating film according to the eleventh invention, wherein the melting point or softening point of the insulating particles is sufficiently lower than the softening point of the substrate.

[0037]

Embodiments of the present invention will be described below in detail.

FIG. 1 shows a sectional view of an insulating film formed on a substrate by the method of the present invention. In FIG. 1, 1 is a substrate, 2 is an insulating layer, 3 is insulating particles, and 4 is a matrix portion made of an insulating material.

The substrate 1 used in the present invention is appropriately selected from, for example, glass substrates such as silicate glass, soda-lime glass, lead glass and borosilicate glass, ceramic substrates such as alumina, metal, and silicon.

The material of the insulating particles 3 used in the present invention includes, for example, borosilicate glass, aluminosilicate glass, soda-lime glass, lead glass, quartz glass, and other metals, and metals and ceramics. For example, glass beads MB-10 (average particle size 5
Glass having a particle size of 2 to 10 μm) is preferably used.

It is desirable that these insulating particles are made of a material having a coefficient of expansion approximately equal to the coefficient of linear expansion of the substrate on which the insulating film is to be formed. If the coefficient of linear expansion of the material of the insulating particles deviates significantly from that of the substrate, during firing, stress is generated due to the difference in the coefficient of thermal expansion,
There is a risk of causing cracks, warpage, peeling, and the like.

The insulating particles have a particle size of 10 nm to 1 nm.
Desirably, the size is about 0 μm. When a particle having a particle diameter smaller than 10 nm is used, it is difficult to uniformly disperse the particles in the coating solution, and it takes time to prepare. Also, 10 μm
If a larger one is used, the particles will settle out immediately in the liquid, making it difficult to apply by a technique such as dipping. The particle size is more preferably 1 μm or less in consideration of the stability of the particle-containing insulating material coating liquid after mixing the particles, the film quality after film formation, and the like.

The insulating particles may be hollow for reasons such as weight reduction of the whole device and electric characteristics.

If the amount of the insulating particles 3 with respect to the liquid insulating material forming the matrix portion 4 exceeds 70% by weight, the whole coating liquid becomes dango-shaped and cannot be coated by a normal method. If the content is less than 10% by weight, the effect on the film thickness is low. Therefore, it is preferable to add an amount in the range of 10 to 70% by weight according to the required film thickness.

The liquid insulating material used in the present invention may be a preparation prepared by dissolving a silane compound such as tetraethoxysilane in a suitable solvent such as ethanol, or a commercially available sol-gel solution (eg:
Any of Atron manufactured by Nippon Soda Co., Ltd. and Tosgard manufactured by Toshiba Silicone Co., Ltd.) may be used. Further, a composition containing a chelate salt of aluminum, an organic alkali metal salt, an organic alkaline earth metal salt, or the like, may be prepared so as to become only an inorganic oxide when calcined (eg:
AY49-208 manufactured by Toray Dow Corning Co., Ltd.). That is, a liquid composition that forms an insulating film by firing is preferably used.

The composition (liquid insulating material) may have a certain degree of viscosity.

Although the polarity of the liquid insulating material can be used even if it is small, it is generally 10 (cal ^1/2 / cm ^3/2 ).
The above may make the insulating particles less likely to settle. It is more preferable that it be 15 (cal ^1/2 / cm ^3/2 ) or more. Further, a commercially available dispersion stabilizer or the like may be added.

Next, a method for forming an insulating film according to the present invention will be described.

As a method for applying the above-mentioned coating solution containing particle-containing insulating material to the substrate, any of generally known methods such as spin coating, dip coating, spray coating, and roll bar coating may be used.

In addition, the coating process need not be performed only once at the time of film formation, and is performed twice or more in order to prevent pinholes, voids, and the like generated due to bubbles and unevenness during coating. May be performed.

In addition, in the coating step, depending on the particle size of the insulating particles and the components of the liquid, the insulating particles may be precipitated immediately after stirring and mixing the insulating particles in the liquid. In such a case, it is preferable to mechanically stir the particle-containing insulating material coating liquid or to stir using an ultrasonic wave until immediately before coating on the substrate.

In the sintering step, after the above-mentioned coating solution of the particle-containing insulating material is applied, temporary sintering is performed if necessary, and then main sintering is performed.

When calcination is carried out after applying the particle-containing insulating material coating liquid to the substrate, usually, the effective component in the insulating material coating liquid, for example, the boiling point of the silicon compound or the like is lower than about 6%.
It is preferable to carry out at a temperature of 0 to 200 ° C., more preferably 60 to 100 ° C., since there is no volatilization of the active ingredient.

The firing is preferably carried out at a temperature at which the alkoxy group of the silicone compound is eliminated and the dehydration reaction sufficiently proceeds, usually at 200 ° C. or higher, more preferably at 350 ° C. or higher.

In the formation method of the present invention, the main baking may be performed after the overcoating is performed. FIG. 2A shows a state in which a minute gap 5 is formed at the interface between the insulating particles 3 and the matrix portion 4 made of the liquid insulating material after the particle-containing insulating material coating liquid is applied and pre-baked or main-baked. Show. FIG. 2 (b) shows that a particle insulating material coating liquid containing no insulating particles (liquid insulating material) or a particle insulating material coating liquid is applied again so as to fill the minute gap 5, baked, and re-coated layer 6 is formed. Shows a state in which is formed.

When the content of the insulating particles in the coating solution is large, the solvent is volatilized when the liquid insulating material forming the matrix portion 4 is baked, and the effective component thereof is formed. Since the matrix also shrinks and shrinks, the capacity of the matrix portion is reduced, and apparently there is a large number of minute gaps 5 in which a large number of insulating particles 3 are arranged (FIG. 2A).

It is desirable that the minute gaps 5 be filled with an insulating material coating solution containing no insulating particles or containing insulating particles smaller than the minute gaps (FIG. 2B). As a method, a liquid insulating material or a particle-containing insulating material coating liquid is dripped and infiltrated on an insulating film having many minute gaps, and then a spin coating method of blowing off an excess liquid or removing excess liquid by a bar of metal or the like is used. A method in which a liquid insulating material or the like is applied by a method such as a roll bar coat or a spray coat in which the fine gap is penetrated with fog and baked is used.

Alternatively, a dip coating method of immersing in a liquid insulating material or a particle-containing insulating material coating liquid, sufficiently penetrating the liquid, and then pulling up the liquid to apply the liquid is used. May go. The lifting speed at this time is preferably lower than that at the time of applying the liquid insulating coating material containing particles, since it is difficult to coat the insulating particles on the outermost layer. If the operation is performed at a high speed, the insulating material is applied thickly on the insulating particles in the outermost layer, and this portion may be finely cracked and peeled off during firing.

It is preferable to apply ultrasonic waves during the dip coating or to perform the dip coating treatment under reduced pressure, since the liquid penetrates into fine gaps between particles.

Here, when using an insulating material coating solution containing no insulating particles, the film thickness after firing is 0.1 to 5 μm.
It is preferable to use a liquid insulating material having a thickness of the order. If the thickness of a single film is extremely small, it must be coated many times to fill the minute gaps between the particles. The gap is not sufficiently filled, and only the outermost layer of the insulating particles is coated.

On the other hand, when a liquid insulating material mixed with insulating particles (coating solution containing particle insulating material) is used, it is desirable that the size of the insulating particles is sufficiently smaller than the size of the minute gap 5. .

As the insulating particles used in the insulating film of the present invention, those having a melting point or softening point sufficiently lower than the softening point of the substrate are used. It is desirable to carry out at a temperature higher than the softening point.
As a preferable material, a low-melting glass having a composition such as PbO—B ₂ O ₃ or PbO—ZnO—B ₂ O ₃ is used. The combination of the substrate, for example, when the substrate is soda lime glass, it is preferable to use a PbO-B ₂ O ₃ composition system glass (Nippon Electric Glass Co., Ltd. LS-3081 (250 mesh) and the like).

FIG. 3 shows a state in which the insulating particles are melted or softened and mixed with the liquid insulating material during the main firing to form a more uniform insulating film having few holes, pinholes and the like.

When the insulating film of the present invention is used as an interlayer insulating film of an image forming apparatus using a surface conduction electron-emitting device, cracking, peeling, etc. can be achieved by appropriately selecting the material and content of the insulating particles. , A dense interlayer insulating film can be formed with a small number of application times.

[0065]

EXAMPLES The present invention will be further described below with reference to examples, but the present invention is not limited to these examples.

Example 1 A sol-gel agent Atron (manufactured by Nippon Soda Co., Ltd.) prepared so that the film thickness after firing was 5 μm was added to glass beads MB-10 (average particle size: 5 μm, average particle size: 5 μm, manufactured by Toshiba Baroteni). (A diameter range of 2 to 10 μm) was added by 60% by weight, and mechanical stirring and ultrasonic stirring were performed until the mixture was uniformly dispersed.

This particle-containing insulating material coating liquid is subjected to dispersion of glass beads by mechanical stirring until immediately before coating, and A4
A 2 mm thick soda-lime glass substrate is immersed in the particle-containing insulating material coating solution for 10 seconds, and a lifting speed of 600 mm /
Raised in minutes.

After sufficiently waiting for the liquid to no longer drip, calcined at 140 ° C. for 15 minutes. In addition, 450 ° C
For one hour.

When the coated product was observed with an electron microscope, the thickness was 34 μm, and particles having a particle size of 2 to 10 μm were observed on the surface of the film. The apparent relative dielectric constant of this insulating layer was 4.5.

Example 2 After the calcination step was completed in Example 1 described above, the sol-gel agent Atron (manufactured by Nippon Soda Co., Ltd.) was prepared so that the film thickness after calcination was 1 μm. It was immersed for 2 seconds and pulled up at a pulling speed of 80 mm / min. After waiting for the liquid to drain completely, remove the substrate
Preliminary calcination at 15 ° C. for 15 minutes. Again, immersion, pulling up, and temporary baking were repeated in the same manner, and finally baking was performed at 450 ° C. for 1 hour.

When the coated product was observed with an electron microscope, the thickness was 35 μm. It was also found that the fine gaps of the particles observed on the surface of the film were filled and flattened by the sol-gel dipping operation this time. Further, the apparent relative permittivity of this insulating layer is 4.
It was 2.

Example 3 In performing the gap filling operation in Example 2 above, ultrasonic waves were not used, and instead the entire dip tank was depressurized to 30 Torr. All other operations were performed by the same operation.

When the coated product was observed with an electron microscope, the film thickness was 35 μm. It was also found that the fine gaps of the particles observed on the surface of the film were filled and flattened by the sol-gel dipping operation this time.

Example 4 A4 size soda-lime glass was immersed in the longitudinal direction by 230
The silver paste was wired with a thickness of 1 μm and a width of 100 μm every μm. Subsequently, as shown in FIG. 4 (a), a negative resist BMRC-1000 (Tokyo Ohka Kogyo Co., Ltd.) was applied by spin coating (600 rpm, 25 seconds) to 30 μm.
m and baked at 80 ° C. for 30 minutes.

Next, as shown in FIG.
After exposing using a mask having a pattern with a line width of 320 μm every m and developing to remove the excess resist, 140
C. for 30 minutes.

Sol-gel solution Tosgard K510 solution (Toshiba Silicone Co., Ltd.) was added to 55% by weight of Toshiba Barotini's MB-10 (average particle size 5 μm, particle size range 2-1).
0 μm) was immersed for 10 seconds in a particle-containing insulating material coating solution in which ultrasonic waves and mechanical stirring were sufficiently dispersed, while applying ultrasonic waves to 600 m.
After lifting at a rate of m / min, a squeegee was applied to the resist and a portion coated thicker than the resist while the surface was not dried to form a pattern of an insulating film. (FIG. 4
(C)).

After calcination at 140 ° C. for 15 minutes, the film is immersed in a sol-gel solution Tosgard K510 for 1 minute while applying ultrasonic waves, and pulled up at a pulling rate of 80 mm / min to fill the minute gaps of the insulating film. After calcining for 1 minute, the body was calcined at 450 ° C. for 1 hour. As a result, FIG.
As shown in (d), the resist was burned by oxygen in the air, and furthermore, the thermal expansion of the resist portion destroyed the insulating material layer adhered thereon, and the resist pattern portion was burned out.

Finally, the residue of the insulating film slightly remaining is removed
It was removed by air blowing with kg / cm ² and washing with water.

When the completed insulating film was measured, it was found that an insulating film having a thickness of 30 μm, a width of 400 μm, and a pitch of 320 μm was formed.

Example 5 The application for filling the minute gaps in Example 4 was carried out under exactly the same conditions except that the method of dip coating was replaced by the method of spray coating. When the completed insulating film was measured, an insulating film having a thickness of about 30 μm and a width of 400 μm was formed.

Example 6 Example 4 was performed by changing only the following conditions.

After spin-coating the resist once, 8
Baking at 0 ° C for 10 minutes, and after cooling, further BMRC-100
0 was spin-coated under the same conditions as the first time,
Baking at 30 ° C. for 30 minutes. The same exposure pattern was used, and the exposure time was doubled. The particle-containing insulating material coating solution was applied to Tosgard K510 solution (Toshiba Silylicone Co., Ltd.).
% By weight of MB-10A manufactured by Toshiba Parotini Co., Ltd. (treated with an amino-based silane coupling agent having an average particle size of 5 μm, a particle size width of 2 to 10 μm, and a weight ratio of 1 ppm) was sufficiently subjected to ultrasonic wave and mechanical stirring. Was used.
Except for the above points, the same operation as in Example 4 was performed.

When the completed insulating film was measured, it had a thickness of 60 μm, a width of 400 μm, and a pitch of 320 μm.

Example 7 Example 4 was carried out by changing only the following conditions.

The substrate used was a 3 mm thick aluminum plate. After spin coating the resist once,
Baking for 0 minutes, cooling, and then adding 1 more BMRC-1000
Spin-coat under the same conditions as the first time,
Bake for 0 minutes. The same exposure pattern was used, and the exposure time was doubled. The particle-containing insulating material coating solution was coated on a 65% by weight aluminum powder (average particle size: 6 μm, particle size width: 3 to 10 μm) in Nippon Soda Co., Ltd. Atron (film thickness after firing: 5 μm).
A solution in which m) was sufficiently dispersed by ultrasonic waves and mechanical stirring was used. Except for the above points, the same operation as in Example 4 was performed.

When the completed insulating film was measured, it was found that the film had a thickness of 60 μm, a width of 400 μm, and a pitch of 320 μm.

Example 8 Example 4 was carried out by changing only the following conditions.

The particle-containing insulating material coating solution was prepared by adding 70% by weight of frit glass powder (LS-3081 (250 mesh) manufactured by Nippon Electric Glass Co., Ltd.) to Atron manufactured by Nippon Soda Co., Ltd. (film thickness after firing is 5 μm). A solution that was sufficiently dispersed by ultrasonic waves and mechanical stirring was used. Also, without performing a gap filling operation, after pre-baking at 140 ° C. for 30 minutes after application,
The main baking was performed at 450 ° C. for one hour. The softening point of the frit glass powder used is 362 ° C. Except for the above points, the same operation as in Example 4 was performed.

When the completed insulating film was measured, it was found that the film thickness was 30 μm, the width was 400 μm, and the pitch was 320 μm. Further, when this insulating film was observed in detail with a microscope, the frit glass was melted and the particle shape was not observed, and the film was uniform.

Example 9 Glass beads Adfine SO-C2 (average particle size, manufactured by Admatex Co., Ltd.) were added to Atoron (manufactured by Nippon Soda Co., Ltd.), a sol-gel agent prepared so that the film thickness after firing was 5 μm. (A diameter of 0.5 μm, a particle size range of 0.1 to 1 μm) was added by 60% by weight, and mechanical stirring and ultrasonic stirring were performed until the particles were uniformly dispersed.

[0091] The glass-containing insulating material coating liquid is subjected to dispersion of glass beads by mechanical stirring until just before coating.
A 2 mm-thick quartz glass substrate was immersed in the particle-containing insulating material coating solution for 10 seconds, and pulled up at a pulling rate of 600 mm / min.

After sufficiently waiting until the liquid no longer dripped off, it was calcined at 140 ° C. for 15 minutes. In addition, 450 ° C
For one hour.

When the coated product was observed with an electron microscope, the film thickness was 34 μm, and particles were observed on the surface of the film. Also, almost no peeling at the periphery was observed.

Example 10 After completion of the preliminary firing step in Example 9 above, the ultrasonic wave was applied to a sol-gel agent Atron (manufactured by Nippon Soda Co., Ltd.) prepared so that the film thickness after firing was 1 μm. And immersed for 80 minutes at a lifting speed of 80 mm / min. After waiting enough for the liquid to disappear, the substrate is heated to 140 ° C.
For 15 minutes. Again, immerse, pull up,
Preliminary firing was repeated, and finally final firing was performed at 450 ° C. for 1 hour.

When the coated product was observed with an electron microscope, the thickness was 35 μm. It was also found that the fine gaps of the particles observed on the surface of the film were filled and flattened by the sol-gel dipping operation this time.

Example 11 When performing the gap filling operation in Example 10 described above, ultrasonic waves were not used, and instead the entire dip tank was depressurized to 30 Torr. All other operations were performed by the same operation.

When the coated product was observed with an electron microscope, the film thickness was 35 μm. It was also found that the fine gaps of the particles observed on the surface of the film were filled and flattened by the sol-gel dipping operation this time.

Example 12 Silver paste was applied to an A4 size quartz glass with a thickness of 1 μm and a width of 100 μm every 230 μm in the longitudinal direction. Subsequently, as shown in FIG. 4A, a negative resist BMRC-1000 (Tokyo Ohka Kogyo Co., Ltd.) was applied by spin coating (600 rpm, 25 seconds) to a thickness of 30 μm and baked at 80 ° C. for 30 minutes. .

Next, as shown in FIG.
After exposing using a mask having a pattern with a line width of 320 μm every m and developing to remove the excess resist, 140
C. for 30 minutes.

Sol-gel solution Tosgard K510 solution (Toshiba Silicone Co., Ltd.) was added 55% by weight of glass beads Adfine SO-C2 manufactured by Admatechs Co., Ltd. (average particle size 0.5 μm, particle size range 0.1-1 μm). Into the particle-containing insulating material coating liquid sufficiently dispersed by ultrasonic and mechanical stirring,
After immersing the resist-patterned glass for 10 seconds while applying ultrasonic waves and pulling it up at 600 mm / min,
The squeegee was applied to the portion of the resist and the portion of the resist that was thicker than the resist while the surface was not dried to form a pattern of an insulating film (FIG. 4C).

After calcination at 140 ° C. for 15 minutes, the sol-gel solution was immersed in Tosgard K510 for 1 minute while applying ultrasonic waves, and pulled up at a pulling rate of 80 mm / minute to fill the minute gaps of the insulating film. After calcining for 1 minute, the body was calcined at 450 ° C. for 1 hour. As a result, FIG.
As shown in (d), the resist was burned by oxygen in the air, and furthermore, the thermal expansion of the resist portion destroyed the insulating material layer adhered thereon, and the resist pattern portion was burned out.

Lastly, a little residue of the insulating film is removed by 4
It was removed with an air blow of kg / cm ² .

When the completed insulating film was measured, an insulating film having a thickness of 30 μm, a width of 400 μm, and a pattern having a pitch of 320 μm was formed.

Example 13 The method for filling the micro gaps in Example 12 was replaced by the method of dip coating to the method of spray coating, and the other conditions were exactly the same. When the completed insulating film was measured, an insulating film having a thickness of about 30 μm and a width of 400 μm was formed.

Example 14 Example 14 was performed by changing only the following conditions.

After spin-coding the resist once, 8
Baking at 0 ° C for 10 minutes, and after cooling, further BMRC-100
0 was spin-coated under the same conditions as the first time,
Baking at 30 ° C. for 30 minutes. The same exposure pattern was used, and the exposure time was doubled. The bead-containing insulating material solution was applied to Tosgard K510 solution (Toshiba Silylicone Corporation).
5% by weight of glass beads Adfine SO-C2 manufactured by Admatechs Co., Ltd. (average particle size 0.5 μm, particle size range 0.
(1 to 1 μm) was sufficiently dispersed by ultrasonic waves and mechanical stirring. Except for the above, the same operation as in Example 12 was performed.

When the completed insulating film was measured, it had a thickness of 60 μm, a width of 400 μm, and a pitch of 320 μm.

Comparative Example 1 A4 size soda-lime glass was coated with a sol-gel solution Nippon Soda Co., Ltd. Atron (5 μm thick after sintering) by dip coating (pulling speed 500 mm / min), followed by 1 hour at 190 ° C. Fired.

Observation of the formed film shows that the film thickness is approximately 5 μm.
m. Further, the film quality was soft and the adhesion was weak. Therefore, the relative dielectric constant could not be measured.

Comparative Example 2 A4 size soda lime glass was coated with a glass paste (7723B) manufactured by Noritake Co., Ltd. by screen printing, and then fired at 500 ° C. for 1 hour.

When this insulating film was observed, the film thickness was about 21 μm.
m, very many irregularities and pores were observed on the surface. The non-dielectric constant was 17.

Comparative Example 3 A4 size soda-lime glass was subjected to dip coating (pulling speed 500 mm / min) using a sol-gel solution Atron manufactured by Nippon Soda Co., Ltd. (film thickness of 5 μm after firing).
m) was applied and calcined at 140 ° C. for 15 minutes. Subsequently, the same sol-gel solution was applied once again to increase the film thickness, temporarily baked for 15 minutes, and then baked at 450 ° C. for 1 hour.

Observation of the film surface after baking revealed that the film thickness was approximately 10 μm, the film was completely peeled off on the outer peripheral portion, and fine cracks were observed on the entire surface of both the first and second layers. Was done. In addition, delamination was observed in some places due to poor adhesion between the first layer and the second layer. Therefore, the relative dielectric constant could not be measured.

Comparative Example 4 A4 size quartz glass was applied with a sol-gel solution Atron manufactured by Nippon Soda Co., Ltd. (film thickness after firing: 5 μm) by dip coating (pulling speed: 500 mm / min), and 140 ° C. For 15 minutes. Subsequently, the same sol-gel solution was applied again to increase the film thickness, and 1
After calcination for 5 minutes, main calcination was performed at 450 ° C. for 1 hour.

Observation of the film surface after baking revealed that the film thickness was approximately 10 μm, the film was completely peeled off at the outer peripheral portion, and the first and second layers were finely cracked over the entire surface. Was observed. In addition, delamination was observed in some places due to poor adhesion between the first layer and the second layer. Therefore, the relative dielectric constant could not be measured.

Table 1 summarizes the above Examples 1 to 8 and Comparative Examples 1 to 3. The items in Table 1 are as follows.

Film thickness and film quality Electron microscope (manufactured by Hitachi, Ltd., FE-SEM (S-
4000)).

Degree of Freeness of Film Thickness When the film thickness can be controlled over a wide range by changing factors such as spin speed, pulling speed, particle diameter, and particle content during film formation, 、 indicates that the controllable range is narrow. The case was evaluated as x.

Insulation Characteristics Aluminum was vapor-deposited in advance on a substrate to be formed into a film having a width of 10 mm. After an insulating film was formed on the substrate, aluminum was vapor-deposited as an upper wiring so as to be perpendicular to the lower wiring. LF impedance analyzer (Hewlett-Packard, HP
4192), the capacitance, the dielectric constant, and the like were calculated. Among the examples, the solid-coated films having the same composition and the same thickness were evaluated for those subjected to patterning, and the results are shown in parentheses.

[0120]

[Table 1]

[0121]

As is apparent from the above description, according to the present invention, by using a particle-containing insulating material liquid in which insulating particles are mixed and dispersed in various liquid insulating materials as an insulating material coating liquid, several μm to several μm can be obtained. An insulating film having a desired film thickness of 10 μm, high resistance and good insulation can be easily formed on various substrates.

Further, according to the present invention, after the application of the particle-containing insulating material liquid, the liquid insulating material containing no insulating particles or containing particles smaller than the fine gaps is applied again, so that cracks, warpage, interlayer damage can be caused. An insulating film without separation or the like can be easily manufactured.

Further, according to the present invention, by appropriately selecting and setting the melting point or softening point of the material of the insulating particles and the firing temperature, it is possible to form an insulating film having uniformity required for insulating properties. Can be.

[Brief description of the drawings]

FIG. 1 is an explanatory view (cross-sectional view) of an insulating layer of the present invention.

FIG. 2 is an explanatory view (cross-sectional view) of an insulating layer of the present invention.

FIG. 3 is an explanatory view (cross-sectional view) of an insulating layer of the present invention.

FIG. 4 is a manufacturing process diagram of the insulating layer of the present invention.

FIG. 5 is a plan view of the surface conduction electron-emitting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Insulating film 3 Insulating particle 4 Matrix part 5 Micro gap 6 Recoating layer 7 Silver paste layer 8 Resist 501 Substrate 502, 503 Device electrode 504 Conductive thin film 505 Electron emission part

Claims (16)

[Claims] 1. A method for forming an insulating film on a substrate, comprising: (1) dispersing insulating particles in an insulating material coating solution;
(2) A method of forming an insulating film, comprising: a step of applying an insulating material coating solution containing insulating particles on a substrate; and (3) a step of baking the substrate to form an insulating film. 2. The method for forming an insulating film according to claim 1, wherein in the firing of the substrate after the application, after the preliminary firing, the final firing is performed at a temperature higher than the temporary firing temperature. 3. The method according to claim 1, wherein the coefficient of linear expansion of the insulating particles is substantially equal to that of the substrate. 4. The insulating particles having a particle size of 10 nm to 10 μm.
The method for forming an insulating film according to claim 1, 2, or 3. 5. The insulating film according to claim 1, wherein the insulating particles are added in a range of 10 to 70% by weight based on the insulating particle-containing insulating material coating liquid. Formation method. 6. After forming the insulating film, the insulating film is formed on the insulating film so as to be able to fill a minute gap formed in the insulating film.
An insulating material coating liquid containing no insulating particles or containing insulating particles smaller than the minute gap is applied and baked.
The method for forming an insulating film according to the above. 7. The insulating film according to claim 1, wherein the melting point or softening point of the insulating particles is sufficiently lower than the softening point of the substrate, and the final baking is performed at a temperature higher than the melting point or softening point of the insulating particles. Formation method. 8. The method for forming an insulating film according to claim 1, wherein an insulating material coating solution containing insulating particles is applied by mechanical stirring until just before coating the substrate. 9. The method for forming an insulating layer according to claim 1, wherein the insulating material coating liquid containing the insulating particles is applied by stirring using an ultrasonic wave until immediately before coating the substrate. . 10. The method of forming an insulating film according to claim 1, wherein said insulating film is formed as an interlayer insulating layer in a method of manufacturing a surface conduction electron-emitting device and an image forming apparatus using said device. 11. An insulating film obtained by applying an insulating material coating solution containing insulating particles on a substrate and baking it. 12. The insulating film according to claim 11, wherein the coefficient of linear expansion of the insulating particles is substantially equal to that of the substrate. 13. The insulating particles having a particle size of 10 nm to 10 μm.
The insulating film according to claim 11, wherein m is m. 14. The insulating film according to claim 11, wherein the insulating particles are added in an amount of 10 to 70% by weight based on the insulating particle-containing insulating material coating liquid. 15. An insulating material coating solution containing insulating particles is applied to a substrate and baked on an insulating film so that minute gaps generated in the insulating film can be filled. An insulating film formed by applying and baking an insulating material coating solution containing no insulating particles or containing insulating particles smaller than the minute gap. 16. The insulating film according to claim 11, wherein the melting point or softening point of the insulating particles is sufficiently lower than the softening point of the substrate.