JP2502390B2 - Method for producing anisotropically conductive ceramic composite - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention has a structure in which electric conductors (including resistors) are densely arranged in an electrically insulating ceramic, and the electric conductivity is present only in a predetermined direction. The present invention relates to a method for producing a directional conductive ceramic composite.

(Prior Art) As a composite of electrically insulating ceramics and a conductive material, there is “Ceramics 21 (1986), No. 7, 60”.
On page 3 ”, β synthesized by chemical vapor deposition (hereinafter referred to as CVD method)
-Si ₃ N ₄ / TiN composites have been described. The composite is obtained by depositing titanium nitride (Ti ₃ ) by a CVD method in amorphous silicon nitride (Si ₃ N ₄ ).
N) is compounded, and TiN with a diameter of about 5 nm is oriented in one direction. Therefore, the composite has illicit conductivity that it does not exhibit conductivity in both directions.

Further, as a method for producing a ceramic composite having a desired thickness, JP-A-52-16654 discloses a component that scatters when heated at a firing temperature (for example, carbon powder) and a component that does not scatter (for example, zirconia). Powder) is mixed, the green sheets coated with the paste are laminated and fired, and then the electrode material is filled into the gaps generated by the disappearance of the scattered components. It is disclosed.

Furthermore, JP-A-60-54865 and JP-A-63-47137.
In the publication, a method for producing a ceramic composite body containing a conductor by forming a paste pattern made of a conductive paste or an organometallic compound on a green sheet by a screen printing method, stacking the paste pattern and baking the paste pattern. Is disclosed.

(Problems to be Solved by the Invention) Since the ceramic composite disclosed in the above document is produced by the CVD method, the conductor may be cut in the middle of the composite or may come into contact with another conductor. The composite may show conductivity in the plane direction. In addition, since the CVD method can produce only a composite having a maximum thickness of about 2 mm, the ceramic composite described above has poor practicability.

Further, in the manufacturing method disclosed in JP-A-52-16654, since non-scattering components remain in the ceramic composite after firing, the electrode material is not sufficiently filled and the conductivity of the conductive portion is reduced. Was sometimes damaged.

Furthermore, JP-A-60-54865 and JP-A-63-47137.
Since the manufacturing method disclosed in the publication uses a screen printing method, the minimum line width and line interval of the paste pattern that can be formed are about 50 μm. When an attempt is made to create a paste pattern having a line width and a line spacing smaller than this, the mesh of the screen mask is fine, which may cause a break in the paste pattern or a short circuit between adjacent paste patterns due to paste sag.
Therefore, in the manufacturing method using the screen printing method, the pitch of about 100 μm is the limit for increasing the density of the paste pattern. Further, as disclosed in this publication, in the method of forming a pattern directly on the green sheet with a conductive paste or a paste of an organic metal compound, the surface of the green sheet is attacked by a solvent contained in the paste. Since it is easy, the components of the paste that can be used are limited. Further, since the green sheet is flexible and brittle, it is impossible to use a mechanically strong method such as screen printing with a high squeegee pressure. In addition to that, since the surface of the green sheet has fine irregularities, there is a problem that the patterns produced due to the irregularities are broken, curved, or short-circuited.

The present invention has been made in view of such circumstances, and an object thereof is to enable a fine wire pattern made of a conductive material to be formed at a higher density and more stably, and to have a desired thickness. Another object of the present invention is to provide a method for producing an anisotropically conductive ceramic composite body in which conductors are densely arranged in ceramics.

(Means for Solving the Problem) The method for producing an anisotropically conductive ceramic composite of the present invention comprises a step of forming a resist pattern on the surface of a support using a photosensitive resin composition, and a step of forming a recess in the resist pattern. After filling the conductive material, the resist pattern is removed to form a fine line pattern made of a conductive material on the surface of the support, and an insulating ceramic material is mainly formed on the surface of the support on which the fine line pattern is formed. A step of forming a ceramics green sheet in which the fine line pattern is embedded by applying a slurry as a component, and a step of laminating a plurality of ceramics green sheets separated from the support, press-bonding, and firing. The above-mentioned object is achieved by the provision.

The manufacturing method of the present invention will be described with reference to FIGS.

First, as shown in FIG. 1A, a resist pattern 2 is formed on a support 1 using a photosensitive resin composition.
The support 1 is preferably a film made of a resin such as polyethylene terephthalate, polyethylene, polypropylene, or polyimide, which has been subjected to a release treatment with a silicone resin, a fluorine resin, or the like, but has a predetermined peeling force and a surface. May be a smooth film or plate.
As the material, glass, metal such as copper or aluminum or stainless steel, resin such as polyethylene terephthalate, polyethylene, polypropylene, polytetrafluoroethylene, or the like can be used. If necessary, it is used as a support after being subjected to a surface treatment using the above-mentioned mold release.
The degree of peeling force may be determined according to the resist pattern of the photosensitive resin composition used in the subsequent steps and the slurry to be applied. Examples of the photosensitive resin composition used to form the resist pattern 2 include a photocurable photosensitive resin composition, a photodegradable photosensitive resin composition, and a photocrosslinkable photosensitive resin composition.

To form the resist pattern 2 on the support, any method conventionally used for producing a circuit board or the like can be adopted. For example, an alkali developing type photoresist is coated on the support 1 if it is a liquid,
If it is a film-like dry film resist, it is laminated, thermocompression bonded, a photomask (not shown) having a predetermined pattern is laminated thereon, and an actinic ray (for example, ultraviolet ray) is irradiated using a high pressure mercury lamp or the like. Examples include a method in which the photosensitive resin in the irradiated portion is cured by irradiation and exposure, and then the photomask is removed, followed by development with an alkaline aqueous solution in which sodium carbonate, sodium hydroxide, potassium hydroxide or the like is dissolved. Further, a resist pattern 2 of about 1 μm can be produced by using an electron beam, an X-ray or the like.

Next, as shown in FIG. 1B, the recesses 2 provided in the resist pattern 2 on the support 1 are filled with a conductive material 3 having a specific resistance smaller than that of a ceramic material described later. The conductive material 3 includes a conductive material and a resistance material having a relatively large specific resistance as long as the material has a specific resistance smaller than that of the ceramic material. Such conductive material 3 includes gold, silver, platinum, palladium, rhodium, copper,
A metal such as nickel, iridium, rhodium, tungsten, molybdenum or an alloy thereof, a metal oxide such as ruthenium oxide, a conductive paste (paint) containing powder or linear material such as carbon, or a resistance paste is preferably used. . The conductive material 3 is formed in the recess 2a of the resist pattern 2.
As a method for filling the, any conventionally known method can be adopted. For example, the conductive material 3 is applied onto the support 1 on which the resist pattern 2 is formed, and a squeegee,
It is preferable to use a spatula or the like to push the conductive material 3 into the concave portion 2a of the resist pattern 2 while stretching the conductive material 3 at a pressure of 0.1 to 10 kg / cm ² .

Next, as shown in FIG. 1C, the resist pattern 2 is removed from the support 1 to form a fine line pattern made of the conductive material 3. The resist pattern 2 is removed by using a solution used for the phenomenon of resist (for example, in the case of an alkali developing type photoresist, an alkaline aqueous solution such as sodium carbonate or sodium hydroxide), etc. It is preferable to elevate the temperature of the solution or to prolong the time so that the water can be sufficiently removed.

Next, as shown in FIG. 1D, a slurry 4 containing ceramic powder having a larger specific resistance than the conductive material 3 as a main component is formed on the support 1 on which a predetermined pattern is formed by the conductive material 3. To apply. The ceramic powder, such as alumina, zirconia, magnesia, sialon, spinel, mullite, crystallized glass, silicon carbide, silicon nitride, aluminum nitride, _{etc., BaO-SiO 2 -B 2 O} 3 -CaO based,
MgO-SiO ₂ -CaO-based, B ₂ O ₃ -SiO ₂ system, PbO-B ₂ O ₃ -SiO
_{2 system, CaO-SiO 2 -MgO-B} 2 O 3 _{system, PbO-SiO 2 -B 2 O} 3 -CaO
System, and mainly composed of glass frit, such as _{SiO 2 -B 2 O 3 -BaO-} CaO based, it may be used alone,
Moreover, you may use together 2 or more types. As the slurry 4, a mixture of ceramic powder and an organic binder and, if necessary, a solvent and a plasticizer is used. Examples of the organic binder include polymer materials such as unsaturated polyester, polyurethane, polyvinyl butyral, polyvinyl alcohol, polymethacrylate, cellulose, dextrin polyethylene, Wanks, starch and casein. Examples of the plasticizer include dioctyl phthalate, dibutyl phthalate and polyethylene glycol. Examples of the solvent include methanol, ethanol, butanol, propanol, acetone, ethyl acetate, benzene, toluene, xylene, water and the like.

The slurry thus prepared is applied onto the support 1 having a fine line pattern formed of the conductive material 3 by the doctor blading method which is generally a method for preparing a green sheet. Then, after undergoing steps such as drying and curing, the support 1 is removed to obtain a green sheet in which the fine line pattern of the conductive material 3 is embedded.

Next, as shown in FIG. 1 (e), a plurality of green sheets in which a fine wire pattern made of a conductive material 3 is embedded are stacked, pressure-bonded, and fired to obtain a pattern as shown in FIG. 1 (f). To obtain an anisotropically conductive Haramix composite. The number of laminated layers is appropriately determined according to the size of the intended anisotropically conductive ceramics composite, but if it is too thick, pressure bonding becomes difficult. For example, if the thickness of the green sheet with the fine line pattern embedded is about 20 μm,
It is desirable to stack about 50 to 1000 sheets. In order to obtain a thicker ceramic composite, a plurality of layers that have been laminated and pressure-bonded may be laminated and then pressure-bonded. Also, the pressure bonding conditions are appropriately determined, but a pressure of 1 to 400 kg / cm ² at 30 to 180 ° C. is set to 1 to 10
It is preferable to apply for a minute. The firing method is appropriately determined depending on the ceramic material used, but
Increase the temperature at 100 ℃ / hr, hold at 400-600 ℃ for 1-5 hours to degrease the green sheet, then increase the temperature again to 760-1650 ℃.
It is preferable to bake for 1 to 5 hours.

The anisotropic conductive ceramic composite obtained by the manufacturing method of the present invention has conductivity only in a predetermined direction. For example, when the fine line patterns are arranged in parallel from one side of the green sheet to the opposite side, the fine line pattern has conductivity only in the direction from one side of the ceramic composite to the opposite side. Further, when the fine line pattern is arranged while curving from one side of the green sheet to the adjacent side, it has conductivity only in the direction from one surface of the ceramic composite to the adjacent surface.

(Example) Next, the present invention will be described in detail based on examples. In the following, "parts" simply means "parts by weight".

Example 1 Methyl methacrylate-n-butyl methacrylate-acrylic acid copolymer (6/2/2, MW = 150,000) 60 parts, 2,2-bis (4-methacryloxydiethoxyphenyl) propane 15
Parts, 15 parts of hexamethylene diacrylate, 2 parts of 2,4-dimethylthioxanthone, 2 parts of ethyl p-dimethylaminobenzoate, 0.05 parts of malachite green, 0.1 parts of paramethoxyphenol and 200 parts of methyl ethyl ketone are uniformly dissolved to form a photosensitive solution. Got The thickness of the obtained photosensitive solution is 25 μm.
A 25 μm-thick dry film photoresist was prepared by coating and drying on the polyethylene terephthalate film. The resulting dry film photoresist was heat-laminated at 100 ° C and 3 kg / cm ² on a polyethylene terephthalate carrier film (100 μm thick, manufactured by Toyo Metalizing Co., Ltd.) release-treated with a silicone resin, and then dry film. A negative photomask having a predetermined pattern was brought into close contact with the polyethylene terephthalate film used in the production of the photoresist, and exposed at 100 mJ by irradiating ultraviolet rays at a distance of 50 cm from a high pressure mercury lamp of 3 kW. Next, remove the polyethylene terephthalate film after removing the photomask, spray a 1 wt% aqueous solution of sodium carbonate at 1 kg / cm ² at 30 ° C., and develop for 35 seconds to give a line width of 50 μm and a line interval of 40 μm on the carrier film. A resist pattern was formed.

Conductive paste (Ag: Pb = 80: 20, polyester film with a resist pattern formed by the above method)
A viscosity of 2400 ps) was applied, and the conductive paste was filled in the recesses of the resist pattern by moving the squeegee to which a pressure of 3 kg / cm ² was applied. Then, the resist pattern was removed by spraying a 1% by weight aqueous solution of sodium carbonate at 30 ° C. at 1 kg / cm ² for 3 minutes. After that, 120 ℃
After keeping it for 20 minutes and drying, the line width is 80 and the line interval is 50μ.
A fine line pattern of a conductor made of the solidified conductive paste of m was formed on the carrier film.

The ceramic slurry was applied onto the carrier film on which the fine line pattern was formed in this manner to prepare a green sheet. Specifically, 40 parts of alumina powder having an average particle size of 3 μm, 60 parts of SiO ₂ —B ₂ O ₃ —BaO—CaO glass frit powder having an average particle size of 5 μm, 12 parts of polyvinyl butyral, 4.5 parts of dibutyl phthalate, and 24 parts of methyl ethyl ketone. Parts, toluene 18 parts, and isopropyl alcohol 18 parts were supplied to an alumina ball mill and kneaded for 3 hours to obtain a slurry. The obtained slurry was supplied to a doctor blade type green sheet producing machine, and this slurry was produced first,
It was applied onto a carrier film on which a fine line pattern was formed. By peeling from the carrier sheet after drying the slurry, 600 green sheets with a fine wire pattern made of a conductive material are laminated on the peeled surface side, 150 ° C, 60 kg
By 3 minutes pressurized crimping under conditions of / cm ^2, 100
A laminate of × 100 × 40 mm was obtained. The obtained laminated body was sliced in a direction perpendicular to the laminated surface to obtain a sliced body having a thickness of 3 mm. The obtained sliced body is supplied to a heating furnace and heated at 10 ° C / h.
The temperature is raised at r and held at 500 ° C for 2 hours to degrease, then 100
By heating at 900 ° C./hr and firing at 900 ° C. for 2 hours, an anisotropic conductive ceramics composite having a thickness of 2.5 mm in which a number of independent conductors were arranged from one surface to the opposite surface was obtained. .

The conductivity of the obtained composite was examined. There was continuity in the thickness direction of the composite, but no continuity in the plane direction. Gold was vapor-deposited on the entire one surface in the thickness direction of the ceramic composite, and needle-like electrodes for measurement were contacted from both surfaces, and the electrical resistance in the thickness direction was measured at 10 measurement points. The average of the 10 points is 4.8Ω
Met.

Example 2 In place of the conductive paste used in Example 1, a resistance paste (RuO ₂ , viscosity 2400 ps) was used, and other than that, Example 1 was used.
A slice was prepared in the same manner as in. The obtained sliced body is heated at 10 ° C./hr and kept at 500 ° C. for 2 hours to degrease,
Then, the temperature was raised at 100 ° C./hr, and the mixture was fired at 860 ° C. for 2 hours to obtain an anisotropically conductive ceramics composite having a thickness of 3 mm. The obtained anisotropically conductive ceramics composite had electrical conductivity in the thickness direction and no electrical conductivity in the plane direction. The electrical resistance in the thickness direction was 27.3Ω as an average value at 10 measurement points.

(Effect of the Invention) According to the manufacturing method of the present invention, an anisotropic conductive ceramic composite body in which electric conductors are densely arranged in a ceramic matrix having a desired thickness can be easily obtained. Since the ceramic composite is manufactured by laminating a plurality of green sheets on the surface of which a fine wire pattern made of a conductor is formed, pressure-bonding and firing, the thickness can be arbitrarily set. Further, when forming the fine line pattern of the conductor, since the resist pattern produced by using the photosensitive resin composition is used, the ceramic composite obtained by the present manufacturing method, the conductor in the predetermined direction Since the thin wire pattern is formed on the support which is arranged at high density and has a smooth surface, there is no disconnection or short circuit of the conductive portion and excellent anisotropy. As described above, according to the present invention, a fine line pattern made of a conductive material is formed at a higher density and more stably, so that a conductor or a low antibody is arranged at a high density in a ceramic having a desired thickness. It becomes possible to obtain the anisotropically conductive ceramic composite body.

[Brief description of drawings]

FIGS. 1 (a) to 1 (f) are schematic explanatory views showing stepwise one embodiment of the method of the present invention. 1 ... Support, 2 ... Resist pattern, 3 ... Conductive material, 4 ... Slurry.

Claims (1)

(57) [Claims] 1. A step of forming a resist pattern on the surface of a support using a photosensitive resin composition, and after filling a concave portion of the resist pattern with a conductive material,
A step of forming a fine wire pattern made of a conductive material on the surface of the support by removing the resist pattern, and applying a slurry containing an insulating ceramic material as a main component to the surface of the support on which the fine wire pattern is formed. By doing so, a step of forming a ceramics green sheet in which the fine wire pattern is embedded, and a step of laminating a plurality of ceramics green sheets separated from the support, press-bonding and firing, are included. Body manufacturing method.