JPH05175660A - Manufacture of low temperature sintered multilayer ceramic board - Google Patents

Abstract

PURPOSE:To prevent a microcrack, a crack, removal of a component and to improve yield of a product by covering the surface of a board with an organic film having a high insulation. CONSTITUTION:A green sheet is obtained from a ceramic mixture for forming a ceramic part 1, and a through hole is formed thereat. Filling a conductor to form a through hole 2 and forming of a wiring pattern 3 are conducted. Then, the sheets are superposed, integrated, binder is removed therefrom in a nonreducing atmosphere, and it is then baked. Thereafter, one surface of a low temperature sintered multilayer ceramic board formed in this manner is coated with polyimide adhesive to form a resin layer to become adhesive 5. Then, a Capton film of an organic film having a high insulation is placed on the adhesive 5, and heated to be adhered. Subsequently, a photoresist pattern is formed on the Capton film 4, and the film 4 is etched.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a multilayer ceramic substrate, and more particularly to a method for manufacturing a low temperature sintered multilayer ceramic substrate.

[0002]

2. Description of the Related Art A conventional low temperature sintered multilayer ceramic substrate is
An example has a cross-sectional shape as shown in FIG. 5, which is mainly composed of aluminum oxide, and is made of forsterite, cordierite, and quartz powder, and is used in combination with a borosilicate glass ceramic portion 11 and gold, silver, silver-- The through hole portion 2 and the wiring pattern portion 3 are made of a metal such as palladium or copper. Such a low temperature sintered multilayer ceramic substrate is manufactured by the following method.

First, Al ₂ O ₃ (aluminum oxide) powder is mixed with SiO ₂ (silicon dioxide), PbO (lead oxide) and B ₂
Mix powder such as O ₃ (boron oxide). Then, an organic binder such as butyral or polyvinyl alcohol and an organic solvent such as trichloroethylene or alcohol are mixed to form a slurry. From this slurry, a ceramic green sheet having a desired thickness is manufactured by a doctor blade casting machine. A hole to be a through hole is formed at a desired position of this green sheet by a drill or a punch.

Separately, gold (Au), silver (Ag), palladium (Pd), or a mixed metal powder thereof, and an organic binder such as ethyl cellulose or nitrocellulose, and α-
A high-boiling organic solvent such as terpineol or n-butyl carbitol acetate is mixed to prepare a conductor paste. Using this conductor paste, conductor filling for forming the through-hole portion 2 and formation of the wiring pattern portion 3 corresponding to each wiring layer are performed on the green sheet after punching by the screen printing method. .. In this way, the desired number of green sheets for which the wiring pattern portion has been formed and the through holes have been filled are aligned and overlapped,
This is pressed and integrated at a temperature (generally 80 ° C. to 150 ° C.) at which the organic binder in the green sheet is softened or higher to be integrated.
The material obtained above is sintered at a temperature of 800 ° C. to 1000 ° C. to complete a low temperature sintered multilayer ceramic substrate. As the atmosphere during sintering, an oxidizing atmosphere, a reducing atmosphere or the like is selected depending on the types of the conductor paste and the organic binder.

[0005]

The low temperature sintered multilayer ceramic substrate manufactured by the above-mentioned conventional method has a mechanical strength of 20 compared with the multilayer ceramic substrate using alumina molybdenum (Mo) and tungsten (W). % -40%
It is inferior, and if the surface of the substrate is plated in a later process, microcracks may be generated due to the stress of the plating.
When brazing components such as / O pins, distortion remains near the brazing material, causing cracks in the board, and the brazed components may fall off and come off, resulting in poor yield. ..

An object of the present invention is to provide a low-temperature sintered multi-layer with good yield, in which microcracks do not occur even if the surface is plated, cracks do not occur even when parts are brazed, and parts do not drop out. A method of manufacturing a ceramic substrate is provided.

[0007]

The first method for producing a low temperature sintered multilayer ceramic substrate according to the present invention comprises at least one highly insulating organic film as an adhesive on at least one surface of the produced substrate. By depositing.

The second method for producing a low temperature sintered multilayer ceramic substrate according to the present invention comprises the steps of applying a highly insulating organic varnish to at least one surface of the produced substrate to form a highly insulating organic film. Have.

The third method for manufacturing a low temperature sintered multilayer ceramic substrate of the present invention includes a step of depositing a highly insulating organic material film on both front and back surfaces of the manufactured substrate.

A fourth method for manufacturing a low temperature sintered multilayer ceramic substrate according to the present invention includes a step of forming a highly insulating organic film by applying a highly insulating organic varnish on both front and back surfaces of the manufactured substrate.

[0011]

Since the highly insulating organic film is formed on at least one surface of the substrate, no microcracks are generated even if the surface is plated, and components such as I / O pins are brazed. , No cracks occur and no parts fall off due to it.

[0012]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a vertical cross-sectional view of a multilayer ceramic substrate manufactured by a first embodiment of a method for manufacturing a low temperature sintered multilayer ceramic substrate of the present invention.

In the method of manufacturing the low temperature sintered multilayer ceramic substrate, first, Al ₂ for forming the ceramic portion 1 is formed by the same steps as the method of manufacturing the multilayer ceramic substrate of FIG.
O ₃ 60wt%, SiO ₂ 30wt%, PbO 8w
A ceramic mixture of t% and B ₂ O ₃ 2 wt% was mixed with butyral and trichlorethylene to form a slurry and then cast to obtain a 0.2 mm-thick green sheet, which had a diameter of 0.25 mm and 2.54 mm. Pitch through holes were formed by punching. The conductor filling for forming the through hole portion 2 and the formation of the wiring pattern portion 3 corresponding to the wiring layer were performed on this green sheet by the same process as the conventional method by the screen printing method. A silver-palladium paste having a composition of 85 wt% silver powder and 15 wt% palladium powder was used for forming the through holes and the wiring pattern. After that, the three green sheets were aligned with each other as shown in FIG. The material obtained above was held in a non-reducing atmosphere at 500 ° C. for 10 hours to sufficiently remove the binder, and then calcined in air at 900 ° C. for 1 hour. Next, LARC-TPI, a polyimide-based adhesive, is applied to one surface of the low-temperature sintered multi-layer ceramic substrate thus formed, and gradually heated to 200 ° C. to 220 ° C. to form the adhesive 5 resin. Layers were formed. Then, the Kapton film 4 having a thickness of 25 [μm], which is a highly insulating organic film, was placed on the adhesive 5 and heated to 350 ° C. under pressure of 40 to 50 kg / cm ² for adhesion. In this example, a varnish-shaped LARC-TPI was used, but a film-shaped LARC-TPI was used.
RC-TPI can also be used. Next, a photoresist pattern was formed on the Kapton film 4.
At this time, a pattern that prevents the photoresist from being deposited on the through-hole portion 2 of the low-temperature sintered ceramic substrate is used, and the Kapton film 4 is etched in a hydrazine solution. A ceramic substrate was obtained.

In this low-temperature sintered multilayer ceramic substrate, the Kapton film 4 which has been applied absorbs and relaxes the stress caused by the later process of brazing and brazing of components and the strain caused by the difference in the coefficient of thermal expansion. However, since the stress and strain applied to the ceramic part 1 are reduced, microcracks do not occur and brazed parts do not fall off.

A metal thin film was deposited on the surface of the product thus obtained, on which the Kapton film was deposited, by sputtering, a photoresist pattern was formed by photolithography, and then electrolytic plating was performed. I / O pins were brazed to the surface on which the Kapton film was adhered, and a thermal shock test at 0 ° C. to 190 ° C. was performed 40 times. While the I / O pin of No. 1 was removed by the crack of the substrate, this product had a crack of 0.01% or less, which was a very good result.

FIG. 2 is a vertical sectional view of a multilayer ceramic substrate manufactured by a second embodiment of the method for manufacturing a low temperature sintered multilayer ceramic substrate of the present invention.

In the first embodiment, a highly insulating organic material film was used, but in this embodiment, a highly insulating organic material varnish was used. That is, one of the surfaces of a low temperature sintered multilayer ceramic substrate obtained by laminating and co-firing ceramic green sheets is uniformly coated with a polyimide precursor varnish by a spin coating method or the like, and then 350 ° C to 450 ° C.
And heated for 30 minutes to form a polyimide layer 6. As the polyimide precursor varnish, for example, Pyralin manufactured by DuPont, Semicofine manufactured by Toray Industries, or Photo Nice can be used. Others are the same as those in the first embodiment.

The low-temperature sintered multilayer ceramic substrate obtained by the manufacturing method of this embodiment also provided the same effects as in the case of the first embodiment.

FIG. 3 is a vertical sectional view of a multilayer ceramic substrate manufactured by a third embodiment of the method for manufacturing a low temperature sintered multilayer ceramic substrate of the present invention.

In this method for manufacturing a low temperature sintered multilayer ceramic substrate, when the adhesive 5 is formed on the multilayer ceramic substrate manufactured by firing the laminated green sheets in the first embodiment, the adhesive is applied to both front and back surfaces of the substrate. the LARC-TPI is applied to form an adhesive 5 ₁ and 5 ₂ is a resin layer, thereon carrying the Kapton film 4 ₁ and 4 _2, respectively, and adhered by heating. The other steps are the same as those in the first embodiment.

The multilayer ceramic substrate manufactured by the method for manufacturing a low temperature sintered multilayer ceramic substrate of this embodiment has the same effect on both front and back surfaces as the surface of the substrate of the first embodiment to which the highly insulating organic film is applied. was gotten.

FIG. 4 is a longitudinal sectional view of a multilayer ceramic substrate manufactured by a fourth embodiment of the method for manufacturing a low temperature sintered multilayer ceramic substrate of the present invention.

In this method for manufacturing a low temperature sintered multilayer ceramic substrate, when the polyimide layer 6 is formed on the surface of the low temperature sintered multilayer ceramic substrate obtained by stacking and firing the ceramic green sheets in the second embodiment, the front and back surfaces of the substrate are Both sides were coated with a polyimide precursor varnish and heated to form polyimide layers 6 ₁ and 6 ₂ . Others are the same as the steps of the second embodiment.

The multilayer ceramic substrate manufactured by the method for manufacturing a low-temperature sintered multilayer ceramic substrate of this embodiment has the same effect on both front and back surfaces as the surface on which the highly insulating organic film is formed in the second embodiment. It was

[0026]

As described above, according to the present invention, by depositing a highly insulating organic material film on at least one surface of a low temperature sintered multilayer ceramic substrate, microcracks are generated even if the substrate surface is plated. Occurrence or I / O
Even if a component such as a pin is brazed, the substrate is not cracked and the brazed portion does not fall off and is removed, so that the product yield is improved.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a multilayer ceramic substrate manufactured according to a first embodiment of a method for manufacturing a low temperature sintered multilayer ceramic substrate of the present invention.

FIG. 2 is a vertical cross-sectional view of a multi-layer ceramic substrate manufactured by a second embodiment of the method for manufacturing a low-temperature sintered multi-layer ceramic substrate of the present invention.

FIG. 3 is a vertical cross-sectional view of a multi-layer ceramic substrate manufactured according to a third embodiment of the method for manufacturing a low-temperature sintered multi-layer ceramic substrate of the present invention.

FIG. 4 is a vertical cross-sectional view of a multilayer ceramic substrate manufactured by a fourth embodiment of the method of manufacturing a low temperature sintered multilayer ceramic substrate of the present invention.

FIG. 5 is a vertical cross-sectional view of a multilayer ceramic substrate manufactured by a conventional example of a method for manufacturing a low temperature sintered multilayer ceramic substrate.

[Explanation of symbols]

1 ceramic portion 2 through holes 3 wiring pattern portions 4 _1, 4 ₂ Kapton films 5,5 _1, 5 ₂ adhesive 6,6 _1, 6 ₂ polyimide layer

Claims (4)

[Claims] 1. A method for manufacturing a low-temperature sintered multilayer ceramic substrate, comprising laminating ceramic green sheets and then firing them together to produce a multilayer ceramic substrate, wherein at least one surface of at least one surface of the manufactured substrate is at least one sheet. A method of manufacturing a low-temperature sintered multilayer ceramic substrate, comprising the step of depositing a highly insulating organic film. 2. A method for producing a low temperature sintered multilayer ceramic substrate, comprising laminating ceramic green sheets and then firing them together to produce a multilayer ceramic substrate, comprising a highly insulating organic varnish on at least one surface of the produced substrate. A method of manufacturing a low-temperature sintered multilayer ceramic substrate, which comprises the step of applying the above to form a highly insulating organic film. 3. The method for producing a low-temperature sintered multilayer ceramic substrate according to claim 1, comprising a step of depositing a highly insulating organic material film on both front and back surfaces of the produced substrate. Manufacturing method of ceramic substrate. 4. The method for manufacturing a low temperature sintered multilayer ceramic substrate according to claim 2, further comprising the step of applying a highly insulating organic varnish on both front and back surfaces of the manufactured substrate to form a highly insulating organic film. A method for manufacturing a low-temperature sintered multilayer ceramic substrate, comprising: