JP2856045B2 - Manufacturing method of ceramic substrate - Google Patents

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 ceramic substrate used for C or a multi-chip module. More specifically, the present invention relates to a method for manufacturing a ceramic substrate having a plurality of cut grooves on its surface.

[0002]

2. Description of the Related Art Conventionally, when a ceramic substrate as described above is manufactured, in order to increase the manufacturing efficiency, a notch groove called a snap line is formed on the surface of a ceramic substrate having a relatively large area. By dividing along the groove, to obtain a large number of ceramic substrates of a predetermined size,
A so-called multi-cavity method is employed.

[0003] In manufacturing a ceramic substrate having the above-described multi-cavity cutting grooves, a surface of a ceramic green sheet, which is generally used as a material of a ceramic substrate to be generally manufactured, is previously provided with a cutter blade, a mold, or the like. To form a notch groove having a lattice shape or other desired shape, and baking it to produce a ceramic substrate having a notch groove on the surface. By dividing the substrate along the cut grooves, a large number of ceramic substrates of a predetermined size can be obtained.

[0004]

However, if the ceramic green sheet having the above-described cut grooves is fired as it is, the ceramic green sheet often shrinks non-uniformly during firing, and the adjacent cuts are cut. The gaps between the grooves are displaced, causing variations in dimensional accuracy, failing to obtain a ceramic substrate of a predetermined size, and reducing the yield.

The present invention has been proposed in view of the above problems, and has as its object to provide a manufacturing method capable of suppressing uneven shrinkage during firing and obtaining a ceramic substrate having good dimensional accuracy. I do.

[0006]

Means for Solving the Problems To achieve the above object, a method of manufacturing a ceramic substrate according to the present invention is as follows. That is, in manufacturing a ceramic substrate having a plurality of cut grooves on the surface, a cut groove is formed on at least one surface of a first ceramic green sheet that is a material of the ceramic substrate to be manufactured. A second ceramic green sheet having a sintering temperature higher than that of the first ceramic green sheet is laminated on both surfaces of the first ceramic green sheet and brought into close contact with each other under pressure. By firing at a temperature lower than the sintering temperature and higher than the sintering temperature of the first ceramic green sheet, only the first ceramic green sheet is sintered, and then the unsintered second ceramic green sheet is sintered. By removing the ceramic substrate, a ceramic substrate having a cut groove on at least one surface is obtained.

[0007]

A cut groove is formed on at least one surface of the first ceramic green sheet as a material of the ceramic substrate to be manufactured as described above, and both sides of the first ceramic green sheet are fired. The state where the second ceramic green sheets having a high sintering temperature are laminated, that is, 2
The first ceramic green sheet is sandwiched between two pieces of the second ceramic green sheets under pressure and adhered to each other, followed by firing, so that the first ceramic green sheets are restrained by the second ceramic green sheets during the firing. As a result, uneven shrinkage as in the prior art is prevented, and it is possible to obtain a ceramic substrate with good dimensional accuracy without causing a variation in the interval between adjacent cut grooves.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing a ceramic substrate according to the present invention will be specifically described below in order with reference to the process diagram shown in FIG. First, as shown in FIG. 1A, a first ceramic green sheet 1 serving as a material of a ceramic substrate is prepared. The first ceramic green sheet (hereinafter, referred to as
For example, a first green sheet 1 is prepared by adding a binder, a plasticizer, and a solvent to a ceramic powder and mixing the slurry with a ball mill or an attractor to form a slurry. The slurry is formed into a sheet by a normal method such as a doctor blade method. What is necessary is just to form.

[0009] A plurality of sheets formed in a sheet shape as described above may be laminated, and the resulting sheet may be pressed and adhered to be used as the first green sheet. In this case, the above-mentioned means for bringing into close contact with each other may be an ordinary method, for example, 50 to 3
What is necessary is just to hot press at 00 kgf / cm < ² > and 60-90 degreeC. The thickness of the first green sheet 1 is not particularly limited, but is preferably about 30 to 200 μm.

As the ceramic powder, a usual raw material used for a conventional ceramic substrate can be used. For example, aluminoborosilicate glass, amorphous glass having a softening point of 600 to 800 ° C, and crystallized glass having a crystallization temperature of 600 to 1000 ° C can be used. Further, ceramic fillers such as alumina, zircon, mullite, cordierite, anorthite, and silica may be added thereto.

As the above-mentioned binder, for example, polyvinyl butyral, methacrylic polymer, acrylic polymer or the like may be used, and as the plasticizer, for example, a derivative of phthalic acid may be used. Further, as the solvent, for example, an ordinary solvent such as an alcohol, a ketone, and a chlorine-based organic solvent may be used.

The first green sheet 1 prepared as described above is cut into a predetermined size, and a conductor paste is applied by screen printing or the like as necessary. When a multilayer substrate is used, the paste is filled into the through holes, and the wiring is printed. Then, as shown in FIG. 1 (b), a cut groove 11 is formed on at least one surface of the first green sheet 1, that is, on one or both surfaces, and the forming means is formed by a conventional method. For example, it may be formed by a method in which a cutter blade is pressed against the surface of the green sheet, or a method in which the blade is cut with a rotary blade.

The cross-sectional shape of the cut groove 11 is V-shaped in the figure, but may be U-shaped or slit-shaped, or any other shape. A shape that does not occur may be selected. The depth of the cut groove 11 is, for example, the first green sheet 1.
(About 1/20 to 8/20) of the thickness (total thickness in the case of stacking as described above).

Next, as shown in FIG.
A second ceramic green sheet (hereinafter, referred to as a second green sheet) 2 is laminated on both surfaces of the green sheet 1. The second green sheet 2 may be manufactured in the same manner as the first green sheet 1 and the thickness thereof is not particularly limited as in the case of the first green sheet 1, but is 30 to 200 μm. The degree is preferred.

As the ceramic powder used for the second green sheet 2, ordinary ceramic powder can be used.
The sintering temperature must be higher than that of the first green sheet 1. For example, when a sintering temperature of 1100 ° C. or less is used as the first green sheet 1,
As the second green sheet 2, for example, alumina, zirconium oxide, aluminum nitride, boron nitride, mullite, magnesium oxide, silicon carbide, or the like can be used. If the particle size of these powders is too coarse, the surface roughness of the ceramic substrate becomes coarse.
About 5 to 4 μm is suitable.

Next, the second green sheet 2 laminated on both sides of the first green sheet 1 as described above is pressed and adhered from both sides. The means for applying pressure and contact may be an ordinary method, and as a result, as shown in FIG. 1 (d), a second groove is formed in the cut groove 11 formed in the first green sheet 1.
A part of the green sheet 2 enters.

Next, the above-mentioned laminated body is placed on a tray T or the like and fired, for example, as shown in FIG. 1 (e), and the firing method may be an ordinary method. However, the firing temperature is lower than the temperature at which only the first green sheet 1 is sintered and the second green sheet is not sintered, that is, the firing temperature of the first green sheet 1. It must be fired at a temperature higher than the sintering temperature.
For the tray T on which the laminate is placed, for example, a normal alumina plate may be used. However, if an alumina plate having good air permeability and high porosity is used, the dimensional accuracy of the adjacent cut grooves is further improved. It is suitable.

After firing as described above, if the unsintered second green sheet 2 is removed with a brush or the like, the sintered green sheet having a cut groove 11 on the surface as shown in FIG. The ceramic substrate 10 is manufactured. The cut groove 11 formed on the surface of the substrate has little variation.
The ceramic substrate having a predetermined size with good dimensional accuracy can be obtained by dividing the substrate.

In the above embodiment, after the cut groove 11 is formed on one side of the first green sheet 1, the second groove is formed on both sides thereof.
2A, the second green sheet 2 is laminated in advance on the surface on which the cut groove 11 is not formed, as shown in FIG. Groove 11
May be formed, and another second green sheet 2 may be laminated on the surface as shown in FIG.

When a plurality of first green sheets are laminated to form a single ceramic substrate, a cut groove is formed after laminating them, and second green sheets are laminated on both surfaces thereof. Alternatively, for example, as shown in FIG. 3, before the plurality of first green sheets 1 are stacked, the cut grooves 11 are formed, and then the plurality of first green sheets 1 and the second May be laminated.

Further, as shown in FIG. 4, a plurality of first green sheets 1 for producing one substrate are provided, and a second green sheet 2 is interposed between the adjacent first green sheets 1. By stacking and stacking the second green sheets 2 on both sides of the stack, and by pressing and bonding them, a plurality of ceramic substrates can be simultaneously manufactured.

In each of the above embodiments, the cut grooves are formed only on one side of the ceramic substrate to be manufactured, but they may be formed on both sides.

[Experimental Example 1] 30.7% by weight of PbO, S
51.7% by weight of iO ₂ , 8.4% by weight of Al ₂ O ₃ ,
Glass powder having an average particle size of 2.2 μm in which 7.3% by weight of B ₂ O ₃ and 1.9% by weight of CaO are mixed, and an average particle size of 1.7
μm alumina powder was mixed at an equal weight ratio. 9 parts by weight of polyvinyl butyral was added to 100 parts by weight of the mixed powder,
7 parts by weight of diisobutyl phthalate, 40 parts by weight of isopropyl alcohol, and 20 parts by weight of trichloroethane were added and mixed by a ball mill for 24 hours to form a slurry.

This slurry was spread by a doctor blade method to produce a ceramic green sheet having a thickness of 131 μm, and five sheets were laminated, and a pressure of 150 kgf / c was obtained.
The first green sheet 1 having a size of 80 mm square was obtained by press-contact with m ^{2 at} a temperature of 85 ° C. The sintering temperature of the first green sheet 1 was 720 ° C.

On the other hand, the same material as that of the first green sheet 1 was used except that zirconium oxide powder having an average particle diameter of 1.3 μm was used instead of the alumina powder. A 145 μm second green sheet 2 was produced. The sintering temperature of the second green sheet 2 was 1600 ° C.

A cutter was pressed against one surface of the first green sheet 1 to form a V-shaped cut groove 11 having a depth of 200 μm in a grid pattern on the entire surface of the sheet. The interval between the adjacent cut grooves 11 was 20 mm, and the dimensional accuracy was within ± 10 μm.

Next, a second green sheet 2 is superposed on both surfaces of the first green sheet 1 one by one.
The laminated body was obtained by pressing and adhering at a temperature of 85 ° C. at a temperature of 85 kg / cm ² . A porosity of 70% having a flatness with a warpage per unit length in the planar direction of 0.05% or less in the laminate.
Placed on a tray T made of alumina plate at a temperature of 520 ° C.
After heating for 3 hours at 900 ° C. for 1 hour, only the first green sheet 1 was sintered. Next, the surface of the laminate was rubbed with a nylon brush to remove the unfired second green sheet 2 to produce a ceramic substrate having a cut groove 11 on the surface.

As a result, the variation in the interval between the adjacent cut grooves 11 of the ceramic substrate is ± 0.05%.
Within this range, a ceramic substrate with extremely good dimensional accuracy was obtained.

[Experimental Example 2] Instead of forming a cut groove with a cutter in Experimental Example 1 above, a rotating diamond saw was used to form a depth of 50 on one surface of the first green sheet.
Cut grooves having a U-shaped cross section of μm were formed in a grid pattern on the entire surface of the sheet. The distance between adjacent cut grooves was set to 20 mm in the same manner as described above, and the dimensional accuracy was within ± 10 μm. Except for this, a ceramic substrate having a cut groove 11 on the surface was manufactured under the same conditions as in Experimental Example 1. As a result, the same results as those of Experimental Example 1 were obtained.

[Comparative Example 1] Two types of ceramic substrates similar to those of Experimental Examples 1 and 2 were produced under the same conditions as above, except that the second green sheet 2 in each of the experimental examples was not used. did. The variation in the interval between the adjacent cut grooves 11 of each ceramic substrate was about ± 0.5% in each case, and it was found that the dimensional accuracy was considerably reduced as compared with the case of the above experimental example.

[Comparative Example 2] In each of the experimental examples described above, instead of forming the cut groove 11 in the first green sheet before laminating the second green sheet on the first green sheet, the first green sheet was laminated. Two types of ceramic substrates similar to those of the above-described experimental examples 1 and 2 under the same conditions as above except that a cut groove 11 was formed in the first green sheet by penetrating the second green sheet on one surface. Was prepared.
As a result, the variation in the interval between the adjacent cut grooves of each ceramic substrate was about ± 1%, and the above Comparative Example 1
It was found that the dimensional accuracy was further reduced even in the case of (1).

As is clear from the above results, according to the above-described experimental example based on the present invention, it is possible to manufacture a ceramic substrate having extremely small dimensional accuracy with little variation in the interval between adjacent cut grooves 11. The reason is that, first, the second green sheet 2 is laminated on both sides of the first green sheet 1 and fired, so that the first green sheet 1 is This is probably because the sheet 2 is constrained by the sheet 2 and shrinks in the thickness direction during firing, but shrinkage in the plane direction is suppressed, and the variation in the shrinkage rate itself and the shrinkage rate is reduced.

Further, as in the present invention, the notch groove 11 is formed on the surface of the first green sheet 1, and the second green sheet 2 is laminated on the surface and pressed and adhered to the above-mentioned notch groove. Since a part of the second green sheet 2 enters the inside 11, the suppressing force against the contraction in the plane direction is further increased as compared with the case where the cut groove 11 is opened, and the contraction amount and the variation are reduced. It is thought to be.

[0034]

As described above, according to the method for manufacturing a ceramic substrate according to the present invention, the adjacent cut grooves 11.
This makes it possible to manufacture a ceramic substrate having extremely small dimensional accuracy with little variation in the interval between the eleventh and eleventh effects, such as an improvement in yield and a significant increase in production efficiency.

[Brief description of the drawings]

FIG. 1 is a process explanatory view of a method for manufacturing a ceramic substrate according to the present invention.

FIG. 2 is a process explanatory view showing a modified example of the manufacturing process.

FIG. 3 is an explanatory view of a process example when a plurality of first ceramic green sheets are laminated.

FIG. 4 is a diagram illustrating a case where a plurality of ceramic substrates are simultaneously manufactured.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st ceramic green sheet 2 2nd ceramic green sheet 10 ceramic substrate 11 cutting groove T tray

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H05K 3/00 B28B 11/00 Z C04B 35/64 BK

Claims (1)

(57) [Claims] When manufacturing a ceramic substrate having a plurality of cut grooves on its surface, a cut groove is formed on at least one surface of a first ceramic green sheet which is a material of the ceramic substrate to be manufactured. And a second ceramic green sheet having a higher sintering temperature than the first ceramic green sheet.
The ceramic green sheets are laminated on both surfaces of the first ceramic green sheet and pressed and adhered to each other, and the laminated body is heated to a temperature lower than the sintering temperature of the second ceramic green sheet and fired. By firing at a temperature higher than the sintering temperature, only the first ceramic green sheet is sintered, and then the unsintered second ceramic green sheet is removed to form a ceramic having a cut groove on at least one surface. A method for manufacturing a ceramic substrate, comprising obtaining a substrate.