JPH0728123B2 - Ceramic wiring board manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a ceramic wiring board having through-holes.

Conventional Technology Conventionally, a ceramic wiring board having a through hole is
The conductor layers were formed by directly through-hole printing thick-film conductor paste on both sides of the ceramic substrate.

An example of the above-described conventional ceramic wiring board having through-holes will be described below with reference to the drawings. FIG. 5 is a sectional view of a ceramic wiring board having through-holes using copper as a conductor material, and FIG. 6 is a manufacturing process diagram thereof.

In FIG. 5, 7 is a ceramic substrate, 2 is a through hole hole, and 6 is a copper conductor layer.

In FIG. 6, first, an unsintered conductor layer is formed of a thick film conductor paste on one surface of a ceramics sintered substrate having through holes. At this time, the conductor layer is simultaneously formed in the through hole. Next, an unsintered conductor layer is similarly formed on the other surface of the ceramic-sintered substrate with a thick film conductor paste. At this time, the conductor layer is formed with a through hole so as to be connected to the conductor layer with the through hole formed from one surface of the ceramic fired substrate. Then, the unfired conductor layer is fired to obtain a ceramic wiring board.

However, the film thickness of the conductor formed on the inner wall surface of the through hole is apt to be thin due to the volume contraction that occurs during firing of the conductor unless the film thickness is precisely controlled because the edge portion of the through hole tends to be thin. There is a problem that disconnection is likely to occur at the edge portion of the hole hole. At this time, as the thick-film conductor paste, when a copper conductor is to be obtained, a copper paste is generally used, but since firing is difficult because it requires delicate atmosphere adjustment for firing conditions, binder removal treatment, When using a copper oxide paste that can easily obtain a copper conductor without requiring a delicate atmosphere adjustment such as a reduction treatment or a firing treatment, the volume shrinkage during reduction-firing is larger in the copper oxide paste, so there is no breakthrough. Hole formation was difficult.

Therefore, the present invention provides a ceramic wiring board having a through hole hole in which the edge portion of the through hole hole is not broken even if the volume contraction occurs during firing of the conductor.

Means for Solving the Problem In order to solve the problem, the present invention relates to a step of continuously forming an unfired insulating layer with an insulating paste on a peripheral edge portion and an inner wall of a through hole of a ceramic substrate having a through hole. A step of forming a conductor layer on the unsintered insulating layer with a conductor paste containing an oxide of a base metal as a main component so that both surfaces of the ceramic substrate are through-hole connected; and a ceramic substrate on which the conductor layer is formed. After heat treatment in the air or in an oxidizing atmosphere and at a temperature sufficient to decompose the organic components contained in the insulating and conductive paste, the base metal oxide in the conductive layer is reduced to a base metal in a reducing atmosphere. Heat treatment at a temperature sufficient to reduce the temperature to a temperature below the melting point of the base metal in a neutral atmosphere and above the temperature at which the conductor layer and the green insulating layer sinter. A heat treatment step.

With this configuration, after the unfired insulating layer is formed in the through hole of the ceramic substrate having the through hole, the through hole is formed on the unfired insulating layer by the through hole connection to form the unfired conductor layer. The unfired insulating layer and the unfired conductor are formed by forming an unfired conductor layer with a conductor paste containing a base metal oxide as a main component on the peripheral portion and the inner wall of the through hole so as to connect both sides of the ceramic substrate to the through hole. Since the layers are fired at the same time, the conductor layer is fired and contracted, and the insulating layer is also simultaneously contracted, so that volume contraction that occurs during firing of the conductor is mitigated, and no breakage occurs in the through-hole portion of the conductor.

Example (Example 1) A sectional view of a ceramic wiring substrate having through-holes, which is one of the examples of the present invention, is shown in FIG. 1, and a manufacturing process diagram thereof is shown in FIG.

In FIG. 1, 1 is an alumina substrate, 2 is a through hole, 3 is a copper conductor layer, and an insulating layer 4 is provided as a base of the copper conductor layer 3.
Is provided.

In FIG. 2, after forming an unsintered insulating layer with a thick film insulating paste on the peripheral portion and the inner wall of the through hole of the alumina substrate having the through hole by screen printing,
An unsintered copper oxide conductor layer was formed by screen printing with a thick film conductor paste containing copper oxide as a main component in a desired region so that both surfaces of the alumina substrate having the through hole holes were through-hole connected. After that, the alumina substrate 1 on which the unsintered copper oxide conductor layer is formed is heat-treated in the air at 500 to 800 ° C. to decompose and remove the organic components contained in the paste, and then nitrogen gas is added to 5 to 20% hydrogen gas. Heat treatment was performed at 300-500 ° C in a mixed gas atmosphere containing copper to reduce copper oxide to metallic copper. And it heat-processed at 850-950 degreeC in nitrogen gas atmosphere, and baked the unbaked insulating layer and the unbaked copper conductor layer simultaneously. The insulating paste is made by mixing a low-temperature sintered glass powder that can be fired at 900 ° C and a powder of alumina powder as the main component, adding a vehicle in which butyral resin is dissolved in a butyrate ester solvent, and kneading with a three-roll mill. did. The conductor paste was prepared by adding a vehicle having copper oxide as a main component and a butyral resin dissolved in a butyric acid ester solvent and kneading with a three-roll mill.

According to this embodiment, the conductor layer is fired and the insulating layer is fired at the same time, so that no disconnection occurs in the through hole portion. Further, copper, which is a base metal, can be obtained as the conductor material.

(Embodiment 2) A sectional view of a ceramic wiring board having through-holes, which is one of the embodiments of the present invention, is shown in FIG. 3, and a manufacturing process drawing is shown in FIG.

In FIG. 3, 1 is an alumina substrate, 2 is a through-hole, 5 is a nickel conductor layer, and an insulating layer 4 is provided under the nickel conductor layer 5.

In FIG. 4, after forming an unsintered insulating layer with a thick film insulating paste by screen printing on the peripheral portion and the inner wall of the through hole of the alumina substrate having the through hole,
An unsintered nickel oxide conductor layer was formed by screen printing from a thick film conductor paste containing nickel oxide as a main component in a desired region so that both surfaces of the alumina substrate having the through hole holes were through-hole connected. After that, the alumina substrate 1 on which the unbaked nickel oxide conductor layer is formed is heat-treated in the air at 500 to 800 ° C. to decompose and remove organic components contained in the paste, and then nitrogen gas is added to 5 to 20% hydrogen gas. Heat treatment was performed at 300-600 ℃ in a mixed gas atmosphere containing nickel to reduce nickel oxide to metallic nickel. And it heat-processed at 850-950 degreeC in nitrogen gas atmosphere, and baked the unbaked insulating layer and the unbaked nickel conductor layer simultaneously. The insulating paste is made by mixing a low-temperature sintered glass powder that can be fired at 900 ° C and a powder of alumina powder as the main component, adding a vehicle in which butyral resin is dissolved in a butyrate ester solvent, and kneading with a three-roll mill. did. The conductor paste was prepared by adding nickel oxide as a main component, a vehicle in which butyral resin was dissolved in a butyric acid ester solvent, and kneading with a three-roll mill.

According to this embodiment, the conductor layer is fired and the insulating layer is fired at the same time, so that no disconnection occurs in the through hole portion. Also, nickel, which is a base metal, can be obtained as a conductor material.

EFFECTS OF THE INVENTION As described above, according to the present invention, after the unfired insulating layer is continuously formed on the peripheral portion and the inner wall of the through hole of the ceramic substrate having the through hole with the insulating paste, the unfired insulating layer is formed. The unfired insulating layer and the unfired conductor layer are formed by forming the unfired conductor layer on the unfired insulating layer with a conductor paste containing a base metal oxide as a main component so as to connect both sides of the formed ceramic substrate through holes. Since and are simultaneously fired, the conductor layer is fired and shrunk and the insulating layer is simultaneously shrunk, so that the strain with the ceramic substrate due to the volume shrinkage that occurs during the firing of the conductor is relaxed, and a disconnection occurs at the edge of the through-hole hole. A ceramic wiring board having a base metal as a conductor material is obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of a ceramic wiring board having through holes using copper as a conductor material according to an embodiment of the present invention, FIG. 2 is a manufacturing process drawing thereof, and FIG. 3 is another embodiment of the present invention. FIG. 4 is a sectional view of a ceramic wiring board having through holes using nickel as a conductor material, FIG. 4 is a manufacturing process diagram thereof, and FIG. 5 is a ceramic wiring having through holes using copper as a conductor material in a conventional method. A sectional view of the substrate and FIG. 6 are manufacturing process diagrams thereof. 1 ... Alumina substrate, 2 ... Through hole, 3 ... Copper conductor layer, 4 ... Insulating layer, 5 ... Nickel conductor layer.

Claims (1)

[Claims] 1. A step of continuously forming an unsintered insulating layer with an insulating paste on a peripheral edge portion and an inner wall of a through hole of a ceramic substrate having a through hole hole, and through-hole connecting both surfaces of the ceramic substrate. A step of forming a conductor layer on the unsintered insulating layer with a conductor paste containing a base metal oxide as a main component, and a ceramic substrate on which the conductor layer is formed in the air or in an oxidizing atmosphere and the insulating and conductor After heat treatment at a temperature sufficient to decompose the organic components contained in the paste, heat treatment at a temperature sufficient to reduce the base metal oxide in the conductor layer to a base metal in a reducing atmosphere, and And a heat treatment at a temperature not higher than the melting point of the base metal and not lower than the temperature at which the conductor layer and the unsintered insulating layer are sintered in a neutral atmosphere. Method of manufacturing a click wiring board.