JPH0411507B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of manufacturing a ceramic substrate having through holes used for example in hybrid integrated circuits.

(Prior Art) Conventionally, ceramic substrates such as hybrid integrated circuits are manufactured as follows.

An unsintered porcelain sheet is prepared by a slurry doctor blade or the like using a mixture of a porcelain composition raw material and an organic binder, and then this sheet is cut into a predetermined shape suitable for example for a hybrid integrated circuit and cut into a predetermined shape. Drill multiple through holes at the locations. This board a ₁
As shown in the second figure, is placed on a sintering base plate b on which a thin layer of, for example, zirconia powder or alumina powder C, which is used as an anti-fusing agent to prevent fusing and reaction, is spread. Then, the anti-fusing agent powder C is spread thinly on the substrate _A1 , and the substrate _A2 is stacked. Approximately 10 to 20 substrates a are stacked in this manner and sintered in a tunnel furnace or the like.

Anti-fusing agent powder adheres to the surface of the sintered porcelain substrate, and the powder also adheres to the inner wall of the through hole, but this porcelain substrate is placed in the same container as the polishing powder and glass beads, and a commercially available barrel is used. Use a polisher to remove powder adhering to the substrate surface.

(Problem to be Solved by the Invention) By the above method, the anti-fusing agent powder C adhering to the surface of the ceramic substrate a is removed, but the powder adhering to the inner wall of the through hole is not removed. tends to remain.
Therefore, there is an inconvenience in that an inspection step to confirm that no powder remains in any of the through-holes and a removal step if any powder remains.

If the above steps are omitted, there will be problems such as the lead wire of the electronic component not being able to be inserted into the through-hole, or the through-hole connection using the conductive paint becoming incomplete.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a ceramic substrate with through holes that does not have the disadvantages of conventional methods.

(Means for Solving the Problems) The present invention involves applying an organic substance to the surface of an unsintered ceramic substrate having through holes, and filling the through holes.
The method is characterized in that an anti-fusing agent powder is spread on the organic coating, and an unsintered porcelain substrate is stacked thereon, and the unsintered porcelain substrate is sintered and the organic material is burned out.

(Function) According to the above configuration of the present invention, the liquid organic substance is burned away at the sintering temperature of the ceramic substrate, and the through hole of the ceramic substrate becomes a cavity. Since the anti-fusing agent powder is not sintered, any adhering to the surface of the ceramic substrate can be removed by conventional means.

(Example) Example 1 An unsintered alumina sheet with a width of 100 mm and a thickness of 1 mm was prepared by mixing a raw material for a porcelain composition containing alumina as a main component and an organic binder using a doctor blade. An unsintered alumina porcelain substrate was prepared by cutting it into a square shape and making 10 through holes of 0.3 mmφ in it.

As shown in the first diagram, a polyvinyl alcohol-based commercially available binder [trade name] is applied to the surface of the substrate 1.
PVA-117] 2 is applied with a brush as it is as an undiluted solution (viscosity 31 CPS), and also applied to, for example, 10 through-holes 3 of the substrate 1.
was filled with the binder 2.

The above process was performed on 100 unsintered alumina porcelain substrates 1, and the top surface of each was 99.8% pure.
of alumina porcelain powder 4 (average particle size 80μm)
It was spread with a mesh sieve to a thickness of about 0.1 mm.

100 unsintered alumina porcelain substrates 1 as described above were stacked on the sintering base plate 5 and heated to 1600°C for 2 hours.
The binder 2 was sintered in a tunnel furnace set to sinter for hours to burn out the binder 2. Since anti-fusing agent powder is attached to the surface of the sintered alumina substrate, 100 of these substrates 1 were placed in a barrel polisher with 5 kg of 1 mm glass beads and 0.5 kg of abrasive for 1 hour. vibrated.

There was no adhesion of anti-fusing agent powder on the surface of the alumina porcelain substrate taken out from the barrel polisher, and the sample
Visual inspection revealed that out of 1000 through-holes, there were zero holes to which the anti-fusing agent powder was adhered.

Example 2 In Example 1, a polyvinyl butyral binder [trade name] was used instead of the polyvinyl alcohol binder applied to the unsintered alumina substrate.
BH-3] with a viscosity of 110 CPS was used in the same manner and under the same conditions as in Example 1. As a result, out of a total of 1000 through-holes in 100 samples, there were zero holes to which the anti-fusing agent powder was attached.

Example 3 In Example 1, a methylcellulose-based binder (trade name) was used instead of the polyvinyl alcohol-based binder applied to the unsintered alumina porcelain substrate.
The same method and conditions as in Example 1 were used, except that 65MP/65EMP) with a viscosity of 3800 CPS was used.

As a result, the number of holes to which anti-fusing agent powder was adhered was zero out of 1000 holes with a total penetration height, similar to the above.
In Examples 1 to 3, the binder 2 was applied only to one surface of the unsintered alumina porcelain substrate, but it may be applied to other surfaces.

Comparative Example The process was carried out in the same manner and under the same conditions as in Example 1, except that in Example 1, an organic binder was not applied to the unsintered alumina porcelain substrate, and alumina powder was directly spread on the substrate, stacked, and sintered. Ta.

As a result, out of a total of 1000 through-holes, there were 402 holes to which the anti-fusing agent powder was attached.

(Effects of the Invention) According to the present invention, an organic material is applied to the surface of an unsintered ceramic substrate having through holes, and the through holes are filled, and an anti-fusing agent powder is spread on the organic material coating. Since the sintered porcelain substrates are stacked and the unsintered porcelain substrates are sintered and the organic matter is burned out, there is no adhesion of anti-fusing agent powder on the inner wall of the through-hole of the porcelain substrate, making it easy to insert lead wires of electronic components. It has the effect of ensuring reliable through-hole connections, eliminating the need for troublesome processes such as 100% inspection of through-holes, and reducing production costs.

[Brief explanation of drawings]

FIG. 1 is a side cross-sectional view showing the laminated state of unsintered porcelain substrates in the manufacturing method of the present invention, and FIG. 2 is a side cross-sectional view showing the laminated state of unsintered porcelain substrates in the conventional manufacturing method. . DESCRIPTION OF SYMBOLS 1... Porcelain substrate, 2... Binder, 3... Through hole, 4... Anti-fusing agent powder, 5... Sintering base plate.

Claims (1)

[Claims] 1 Apply an organic substance to the surface of an unsintered porcelain substrate having through-holes and fill the through-holes, spread an anti-fusing agent powder on the coating of the organic substance, stack the unsintered porcelain substrates, and A method for manufacturing a porcelain substrate, characterized by sintering the porcelain substrate and burning out the organic matter.