JPS6399957A - Material for formation of pores - Google Patents

Abstract

PURPOSE:To obtain a material for forming fine and highly precise pores which can be formed by using a photolytically photosensitive resin as a photosensitive resin in which a pattern is formed. CONSTITUTION:A ceramic green sheet in which a highly precise pattern of pores has been formed by using a photosensitive resin and another ceramic green sheet are laminated, thermally compressed and baked. In this manufacturing method which forms pores in a ceramic base, a material for formation of pores which consists of photolytically photosensitive resin as a main component is used as a photosensitive resin. The material for formation of pores containing a main component of photolytically photosensitive resin is of a quinonediazito group represented by an orthonaphthoquinonediazide compound or of a nitrocompound group. These compounds mixed with acrylic acid copolymer, unsaturated organic acid copolymer and alkali-resoluble resin such as phenolnovolake, or bonded with high polymers such as phenolnovolak are preferably used. A pore pattern is formed with a photosensitive resin, so it is possible to form a pattern of very fine pores with high precision.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a pore-forming material for forming fine pores with high precision in a ceramic substrate.

(Conventional technology) Conventional methods for forming pores in ceramic bases include:
Methods that have been used include applying a paste such as carbon that decomposes and scatters at temperatures below the ceramic firing temperature, or pressing a press plate onto the ceramic green sheet. For example, in multilayer ceramic capacitors, carbon-containing paste is applied onto a green sheet, laminated and crimped, and then sintered, holes are formed in the area where the carbon paste is applied, and metal such as lead is press-fitted into the holes to form internal electrodes. (Japanese Unexamined Patent Publication No. 52-16654, Japanese Patent Publication No. 53-35
Publication No. 085). In addition, in inkjet heads, holes are formed in the ceramic substrate by pressing a metal press plate onto the green sheet, or by embedding an acrylic sheet mold into the green sheet and firing it (Japanese Patent Application Laid-Open No. 58-
No. 87060@).

(Problems to be Solved by the Invention) However, conventional hole forming methods have had problems such as lack of accuracy and inability to form holes with a large thickness. When forming a pattern on a green sheet using a screen printing method using a paste such as carbon that decomposes and scatters at high temperatures, it will cost 100 yen due to the accuracy of screen printing.
The limit was to form a 1 m wide pattern with a pitch of 200 pm. Also, in this case, the pattern thickness is at most 10
pm, and the film thickness was extremely non-uniform, making it insufficient for use as pores for electronic components.

Furthermore, when holes are formed using a metal press plate or a plastic film press plate, it is difficult to form a highly accurate pattern due to deformation due to pressure.

In particular, in the method of forming a recess on a green sheet by applying pressure using a metal press plate, a ceramic sheet forming a lid member is further layered on top of the recess, and when the ceramic sheet is bonded under heat, a portion of the green sheet overlapped in the recess is removed. The problem is that the thickness of the holes becomes significantly uneven depending on the location.

When an acrylic sheet is used as a press plate, the acrylic sheet is deformed when it is embedded in a green sheet by pressure or thermocompression bonding, resulting in poor precision.

The properties required of a pore-forming material in order to form pores in ceramics with high precision are summarized as follows.

(1) A thick film can be formed uniformly and over a wide range of thicknesses.

(2) Fine pattern formation is possible.

(3) There is little deformation of the pattern during the lamination and crimping processes.

(4) Phenomena such as rapid decomposition, melting, expansion, and deformation do not occur during the thermal decomposition process.

(5) There is no residual bone after decomposition.

An object of the present invention is to provide a pore-forming material that satisfies all of the characteristics necessary for a pore-forming material as described above and can form fine pores in ceramics with unprecedented precision.

(Means for Solving the Problems) The gist of this invention is to laminate a ceramic green sheet in which a highly accurate hole pattern is formed using a photosensitive resin and another ceramic green sheet, bond them under heat, and then sinter them. By doing so, the photosensitive resin used in the manufacturing method of forming pores in a ceramic substrate can (1) form a film with a uniform thickness over a wide range, and (2) form a fine pattern regardless of the film thickness. (3) There is little deformation of the pattern during the lamination and pressure bonding process. (4) There is no phenomenon such as sudden decomposition, melting, expansion, or deformation during the binder removal process. (5) After decomposition, There is no residual bone, and our goal is to provide a material that satisfies your needs. Among these necessary characteristics, the pattern film thickness is 10 pm to 110 pm.
It is desirable that a thickness of about 00p can be achieved, and the accuracy of the film thickness is preferably ±10% or less.

Furthermore, although the accuracy of the fine pattern depends on the thickness of the pore-forming material, it is desirable that the aspect ratio be 0.5 or more.

A photosensitive pore-forming material that satisfies all of these characteristics is a pore-forming material whose main component is a photodegradable photosensitive resin.

Examples of pore-forming materials whose main component is photodegradable photosensitive resins include quinonediazide-based materials such as orthonaphthoquinonediazide compounds and nitro-compound-based materials. , unsaturated organic acid copolymerized polymers, those mixed with alkali-soluble resins such as phenol novolak, or combined with polymers such as phenol novolak are preferably used.

For development, a solution capable of dissolving the exposed area, such as an aqueous organic alkali solution such as ethanolamine or triethanolamine, or an aqueous inorganic alkali solution such as potassium hydroxide, sodium carbonate, or trisodium phosphate, is used.

Here, as a support for providing a photosensitive resin layer,
Examples include a carrier film such as polyester, a glass plate, a metal sheet, a ceramic green sheet, and a ceramic green sheet is particularly suitable. In addition, even in the case of a support plate other than a ceramic green sheet, it is an effective method to transfer the pattern to the green sheet after pattern formation, peel off the support plate, and essentially replace the support with the green sheet. It is. By using a green sheet as the support in this way, if it is crimped to another green sheet with a pattern interposed therebetween, the pattern will be embedded in both green sheets, forming holes with an ideal shape. Can be done. Furthermore, when using something other than a green sheet as a support, it is necessary to peel it off from the pattern during heating and baking.

In this method of manufacturing a ceramic substrate having pores, it is possible to form a precise and fine pore pattern by using a photosensitive resin. It is important that the ceramic green sheet and the hole-forming pattern are laminated and pressure-bonded, rather than being buried.

(Function) In the present invention, since a hole pattern is formed using a photosensitive resin, it is possible to form a very fine pattern with high precision.

Using the photosensitive resin of the present invention, it is easy to form a pattern width of about 10 pm at a pitch of 20 pm even with the technology currently in practical use. Also, the maximum thickness is several mm.
It is also possible to realize an aspect ratio of 1 or more, which is the ratio of the width and thickness of the pattern.

Furthermore, in the step of forming holes, when embedding a pressing plate or the like into the green sheet by applying pressure as in the prior art, the depth of embedding is several tens of pm, which is its own limit. In addition, high pressure is required for deep embedding, and the hole pattern is deformed during embedding, making it impossible to maintain accuracy.

- The depth of the hole pattern embedded in the green sheet is divided into two in the upper and lower directions in the process of simultaneously press-bonding the hole pattern formed by using the photosensitive resin of Riki's invention and the ceramic green sheet. Because it uses a photosensitive resin that does not deform, the pore pattern deformation is unlikely to occur, and since multiple ceramic green sheets are pressed together at the same time, the green sheet deforms to fill the gaps in the pore pattern when pressurized. , almost no deformation of the hole pattern is observed, making it possible to form a highly accurate pattern.

(Example) Hereinafter, the pore-forming material of the present invention will be explained in detail with reference to Examples.

Figures 1 and 2 (a) to (D) show a pore forming process using the pore forming material of the present invention. First, a photosensitive resin 1 is placed on a carrier film 2 such as polyester in a predetermined amount. Coat to a uniform thickness (Figure 2 (a))
. A photomask 3 with a predetermined pattern formed thereon is closely attached to the photosensitive resin 1 thus produced, and after exposure by irradiating light, a development process is performed to form a predetermined hole pattern 4 (second Figures (b), (c)).

The photosensitive resin is a pre-decomposed photosensitive material consisting of 20% by weight of an esterified product of naphthoquinonediazide sulfonic acid and pyrogallol, 60% by weight of ethylene glycol monoethyl ether, 19% by weight of methyl ethyl ketone, and 1% by weight of methyl violet (dye). The oil solution was applied and dried to remove the solvent. This resin is irradiated with ultraviolet rays through a required mask pattern using a 3kW ultra-high pressure mercury lamp, and the portions selectively irradiated with ultraviolet rays through the mask pattern are dissolved and removed using a 1% aqueous sodium hydroxide solution to form a pore pattern. Formed.

On the other hand, the ceramic green sheet 5 is made into a slurry by mixing and dispersing ceramic powder, an organic binder, a plasticizer, and a solvent according to a general method, and then it is made into a slurry by doctor blade method, casting method, etc. It is created by coating it on a sheet and drying it.

After drying, this ceramic green sheet is peeled off from the formed film or plate and punched or cut into predetermined dimensions. The thus obtained green sheet may have through holes formed therein by punching or the like, or an electrode paste 6, a resistance paste, a dielectric paste, etc. may be printed on the surface of the green sheet, as required.

The hole pattern 4 is difficult to peel off from the carrier film, and is laminated together with the ceramic green sheet 5 into a mold for compression so that the holes, electrodes, and other printed patterns are arranged in a predetermined three-dimensional manner. Apply pressure to integrate.

Here, heat can be applied along with pressure as necessary (Fig. 2(d)).

(e)).

The laminate 7 thus created is cut into predetermined dimensions as required, and then the pore pattern and organic matter present in the ceramic green sheet are removed by slow heating in an oxidizing atmosphere in a single debinding step. , decompose and disappear. Normally, these organic substances are completely decomposed and oxidized by 500°C to 600°C, but if the temperature is suddenly raised to the decomposition temperature, the laminate will be damaged, so the temperature should be kept at a temperature of 25°C or more slowly. Raise the temperature at a rising speed,
By holding the temperature at 500°C to 600°C for a sufficiently long time, the organic matter is completely disappeared (Fig. 2(f)).

The photosensitive resin used here did not cause any cracks, deformation, or delamination during the binder removal step.

Since no organic matter remains in the laminate after the binder removal process as described above, the voids and hole pattern portions remain as voids 9 in the laminate. This laminate is sintered at a predetermined temperature to form a ceramic 10, which is then cut into predetermined dimensions as needed to form an electronic component.

FIGS. 3(a) and 3(b) show a plan view and a cross-sectional view, respectively, of an on-demand inkjet head integrated with ceramic electrodes prepared using the present photodegradable photosensitive resin.

In this on-demand type inkjet head, a PbTiO3-PbZrO3 ceramic was used as the piezoelectric ceramic 11. In addition, the material of the electrode 12 is A
An electrode paste with a g/Pd ratio of 70/30 (weight ratio) was used. The photodegradable photosensitive resin for hole patterns is made by esterifying naphthoquinonediazide sulfonic acid and an esterified product of gallic acid and p-methylphenol3.
．． A photodegradable photosensitive resin solution consisting of 5% by weight, phenol novolak (17.5% by weight of sealant, 70% by weight of ethylene glycol monomethyl ether acetate and 9% by weight of xylene) is applied and dried to form ethylene glycol monomethyl ether acetate and xylene. Using a 3kW ultra-high pressure mercury lamp, this resin coating was irradiated with ultraviolet rays through the required mask pattern, and the selectively irradiated areas were treated with 4% triethanolamine. It was developed with an aqueous solution to form a hole pattern faithful to the mask.

Crimping of ceramic green sheet and hole pattern is 25
A pressure of 0 kg/cm2 was applied and heating was carried out to a temperature of 110°C for 30 minutes. The laminate was heated in air at a heating rate of 5°C I hours and held at 500°C for 3 hours to decompose and eliminate organic matter.

Sintering was also carried out in air and held at 1150°C for 2 hours.

When an AC voltage of 40 V was applied to the electrodes of the inkjet head formed in this manner, the electrode forming portion vibrated due to the piezoelectric transverse effect, and ink droplets were confirmed to be ejected from the nozzles 13. The shape of the formed nozzle part is 11
00p angle, and the height of the internal pressure chamber 14 is 11
At 00p, holes with a maximum width of 5 mm were formed.

FIGS. 4(a) and 4(b) show a plan view and a sectional view, respectively, of a bubble-type inkjet head made using the pore-forming material of the present invention. In this head, insulator ceramic 1
A mixed powder of lead borosilicate glass and alumina is used as the raw material for the conductor 16, and Ag/
A material with a Pd ratio of 85/15 (weight ratio) was used.

The hole pattern was formed by the method used when forming the on-demand inkjet head.

Crimping of ceramic green sheet and hole pattern is 30
It was carried out at a pressure of 0 kg/cm2 and a temperature of 80°C. The heater resistor 19 for generating bubbles was formed using a ruthenium oxide paste. After decomposing the organic matter at 500°C, it was held at 900°C for 2 hours and sintered.

When the ink retainer 18 was filled with ink and a high frequency pulse was applied to the internal resistance 19 of the bubble type inkjet head, it was confirmed that the ink was ejected from the nozzle 17. The nozzle dimensions are 50 pm square.

FIGS. 5(a) and 5(b) show a plan view and a sectional view of a piezoelectric sounding body formed using this method.

Here, a PbTiO3-PbZrO3 piezoelectric material was used as the piezoelectric ceramic 11, and platinum was used as the constant loss material.

The pore pattern is esterified product 1 of orthonaphthoquinonediazide sulfonic acid and trihydroxybenzophenone.
Using a film obtained by applying and drying a photodegradable photosensitive resin solution consisting of 0% by weight, methyl methacrylate, 30% by weight of a copolymer of methyl acrylate and p-hydroxyethyl acrylate, and 60% by weight of xylene. The coating was selectively photodecomposed by irradiating ultraviolet rays with a 3kW ultra-high pressure mercury lamp through a required mask pattern, and the photodecomposed portion was dissolved and removed with a 1% trisodium phosphate aqueous solution. . Further, the piezoelectric sounding body has an air chamber 24 via a drive section of the piezoelectric ceramic 11 that includes some electrodes 21 inside, and this air chamber 24 communicates with the outside through a hole 23. Further, conductor wiring 22 is also formed.

After sintering, when an alternating current voltage was applied to the electrode, a 1 kHz sound was generated. In this case, holes are formed in the housing above and below the vibrating body in the form of green sheets, so that sound is transmitted to the outside.

(Effects of the Invention) It has been confirmed that by using the pore-forming material of the present invention, highly accurate pores can be formed in ceramics at a high yield, and the pore shapes can be formed in a wide range.

In addition to the inkjet head sounding bodies listed in the examples, the materials of the present invention include ceramic filters, ceramic vibrators, ceramic oscillators, piezoelectric speakers, piezoelectric microphones, ceramic sensors, ceramic heat pipes,
It can be applied to any component device using a ceramic substrate that requires pores such as, and a great effect can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a manufacturing process of a ceramic substrate having pores using the pore-forming material of the present invention. Figure 2(a)~
(O is also a process flow diagram, Figures 3 (a) and (b) are a plan view and a sectional view of an on-demand inkjet head, respectively, and Figures 4 (a) and (b) are a plan view of a bubble type inkjet head. 5(a) and 5(b) are a plan view and a sectional view of the piezoelectric sounding body. In the figures, 1 is a photosensitive resin, 2 is a carrier film, 3 is a photomask, and 4 is an empty space. Hole pattern, 5 is ceramic green sheet, 6 is printed electrode paste, 7
1 is a laminate obtained by pressing green sheets, 8 is an electrode or resistor after sintering, 9 is a hole formed in the ceramic, 1
0 is sintered ceramics, 11 is piezoelectric ceramics,
12 is an electrode for driving piezoelectric ceramics, 13 is a nozzle, 14 is a pressure chamber, 15 is an insulator ceramic, 1
6 is a wiring conductor, 17 is a ceramic nozzle, 18 is an ink retainer, 19 is a resistor for bubble generation, 21 is a piezoelectric ceramic drive electrode, 22 is a conductor wiring part that conducts electricity to the drive electrode, 23 is a hole, 24 is formed in ceramics and is empty. 2 Figure (a) lq /8

Claims (1)

[Claims] A desired pattern is formed using a photosensitive resin, the pattern is laminated with a ceramic green sheet, the pattern is embedded in the sheet, and the sheet and the pattern are heated to make the pattern disappear. A pore-forming material characterized in that the photosensitive resin used to form the pattern is a photodegradable photosensitive resin when a ceramic substrate having pores is obtained by firing the sheet.