JP2002201077A - Method of manufacturing ceramic substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a ceramic substrate capable of eliminating an organic substance easily and controlling temperature easily. SOLUTION: The method of manufacturing the ceramic substrate is that a setter of ceramic and a green sheet are laminated and sintered at 800-1,000 deg.C, and the porosity of the ceramic forming the setter is 40-80%.

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 low-temperature fired ceramic multilayer substrate for mounting an integrated circuit and the like, and more particularly to a method for firing a substrate.

[0002]

2. Description of the Related Art In recent years, electronic circuits have been increasing in density.
Utilizing a low-temperature fired ceramic multilayer substrate, miniaturization of circuit boards and devices has been realized. When manufacturing a low-temperature fired ceramic multilayer substrate, a green sheet made of ceramic powder and an organic substance is used. By stacking and sintering a plurality of the green sheets, a low-temperature fired ceramic multilayer substrate is manufactured.

Here, a conventional technique will be described with reference to FIG. In FIG. 3, 3 is an alumina setter and 2 is a green sheet laminate. In a substrate firing step in a conventional manufacturing process of a low-temperature fired ceramic multilayer substrate, a green sheet laminate in which a plurality of green sheets in which via holes and inner layers are formed in advance is placed on an alumina setter as shown in FIG. Then, the substrate was fired using a box-shaped firing furnace or a belt firing furnace.

[0004]

The substrate baking step includes a step of removing organic substances and a step of sintering ceramic powder. However, the conventional method has the following problems.

First, in a substrate firing step for firing the green sheet laminate, it is necessary to remove organic substances before sintering the ceramic powder. Specifically, about 300 ° C to 500
Burn organic matter at a temperature of ° C. If the organic substances cannot be sufficiently removed, not only will the sintering of the ceramic powder be seriously affected, but also the properties of the sintered ceramic substrate itself will be degraded due to residual carbides, for example. The alumina setter on which the green sheet laminate is conventionally used has a low porosity, so that when removing this organic substance, the removal of the organic substance at the lower part of the green sheet laminate where the green sheet laminate and the alumina setter are in contact It was difficult to do. In particular, when the substrate is fired in a box-type firing furnace, it is effective to fire as many substrates as possible at once to increase the working efficiency. However, at this time, there was a problem that the more the number of the green sheet laminates, the more difficult it was to remove organic substances.

Second, as the number of the green sheet laminates to be put into the box-shaped firing furnace increases, the amount of heat required for removing organic substances and sintering the ceramic powder increases, and the amount of heat required for removing organic substances increases. In addition, there is a problem that the temperature control for sintering the ceramic powder becomes very difficult.

Third, a setter is disposed between the green sheet laminates in order to bake at least one green sheet laminate at a time, and a plurality of green sheet laminates and setters are laminated and fired simultaneously. In this case, there were similar problems as described above.

Accordingly, an object of the present invention is to provide a method of manufacturing a ceramic substrate in which organic substances can be easily removed and the temperature can be easily controlled in order to solve the conventional problems.

[0009]

In order to achieve the above object, a method of manufacturing a ceramic substrate according to the present invention is characterized in that a setter made of ceramic and a green sheet are superposed on each other.
A method of manufacturing a ceramic substrate which is fired at a temperature of from 00 ° C to 1000 ° C, wherein the porosity of the ceramic forming the setter is from 40% to 80%.

As a result, the porosity of the ceramic is reduced to 40%.
By increasing the value to 80%, it becomes easy to remove organic substances, and it is particularly effective for removing organic substances at the lower part where the setter and the green sheet are in contact. Also, the effect is greater as more green sheets are fired simultaneously.

In the method for manufacturing a ceramic substrate according to the present invention, it is preferable that the green sheet has a laminated structure.

In the method for manufacturing a ceramic substrate according to the present invention, the setter is preferably made of ceramic having a specific heat of 4.2 kJ / (kg · K) or less.

[0013] Thus, as the number of the green sheets or the laminates to be put into the firing furnace increases, the organic matter can be removed, and the amount of heat required for sintering the ceramic powder can be reduced. It also facilitates temperature control required for sintering of ceramics and ceramics.

Further, in the method of manufacturing a ceramic substrate according to the present invention, it is preferable that a plurality of the setters and the green sheets are stacked and fired simultaneously.

As a result, more substrates can be fired at one time, so that the manufacturing cost can be reduced and a more inexpensive ceramic multilayer substrate can be provided.
The porosity of the setter used at this time is 40% or more.
Since it has a characteristic of 80% and a specific heat of 4.2 kJ / (kg · K), there is no problem in removing organic substances and sintering ceramic powder.

[0016]

Embodiments of the present invention will be described below.

FIG. 1 is a sectional view of a green sheet laminate and a setter showing an embodiment of a method for manufacturing a ceramic substrate according to the present invention. In FIG. 1, 1 is a setter, 2 is a green sheet laminate, and 4 is a pore in the setter.

FIG. 2 is a sectional view of a plurality of green sheet laminates and a plurality of setters showing another embodiment of the method of manufacturing a ceramic substrate according to the present invention. In FIG. 2, 1 is a setter, 2 is a green sheet laminate, and 4 is a pore in the setter.

As the ceramic powder which is a raw material of the green sheet used in the present invention, generally, a mixture of alumina powder and glass powder at a ratio of about 50 to 50 can be used.
More specifically, Al ₂ O ₃ : 13.97 to 60% by mass,
SiO ₂ : 22.8 to 56.52% by mass, B ₂ O ₃ : 2.
32 to 5.1 wt%, Na ₂ O: 0.6~2.1 wt%, K ₂ O: 0.6~1.56 wt%, CaO: 2.4
４4.8 mass%, MgO: 0.84 to 8.53 mass%,
PbO: The total amount is 100 in the composition range of 7.2 to 12% by mass.
Compositions selected to be wt% can be used.

The organic substance used as a raw material of the green sheet used in the present invention comprises a solvent and a binder. As the solvent, methyl ethyl ketone (MEK), toluene and the like can be used. In addition, an acrylic resin or the like can be used as the binder.

A slurry is prepared by adding the solvent and the binder to the ceramic powder, and a green sheet having a thickness of 0.2 mm is formed using a conventional doctor blade method.

The green sheet is cut into a 150 mm square, a via hole for interlayer connection and a hole for alignment are formed at predetermined positions, and a silver paste is filled in the via hole as a conductive paste to form an arbitrary inner layer pattern. -Is formed. After filling the via hole with the conductive paste and forming the inner layer pattern, drying is performed at 50 ° C. to 100 ° C. for about 30 minutes, respectively.

Next, positioning is performed by inserting positioning holes formed in the green sheet into positioning pins prepared in advance in the laminating jig, and a predetermined number of sheets are laminated. The green sheet laminate is completed.

The thus prepared green sheet laminate has a porosity of 40% to 80% and a specific heat of 4.0 as shown in FIG.
It is placed on a ceramic setter having characteristics of 2 kJ / (kg · K) or less. Thereafter, the organic matter is removed at 500 ° C., the substrate is sintered at 900 ° C., and then a predetermined outermost layer conductor is formed to complete the ceramic multilayer substrate.

The step of removing the organic substances and sintering the substrate may be carried out in a batch using a box furnace, or after removing the organic substances in the box furnace, sintering the substrate using a belt firing furnace. You may do it.

At this time, the form of the green sheet laminate and the setter may be a single-stage as shown in FIG.
As shown in (2), a setter may be arranged between green sheet laminates, and a plurality of green sheet laminates and setters may be stacked.

[0027]

According to the method for manufacturing a ceramic substrate of the present invention,
First, by increasing the porosity of the setter used in the substrate baking step to 40% to 80%, it becomes easy to remove organic substances, and it is particularly effective in removing organic substances below the contact between the setter and the green sheet laminate. .

Second, the specific heat is 4.2 kJ / (kg · K)
By using the following setter, the more the green sheet laminate to be put into the firing furnace, the more the amount of heat required to remove the organic substance and sinter the ceramic powder can be suppressed, and the amount of the organic substance can be reduced. The temperature control required for removal and sintering of the ceramic is also facilitated.

Third, by arranging a setter between green sheet laminates and stacking a plurality of green sheet laminates and setters and firing them at the same time, more substrates can be fired at one time and the manufacturing cost is reduced. It is possible to provide a less expensive ceramic multilayer substrate. The setter used at this time has a porosity of 40% to 80% and a specific heat of 4.2 kJ / (kg · K).
Therefore, there is no problem in removing organic substances and sintering the ceramic powder.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a green sheet laminate and a setter according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a green sheet laminate and a setter showing another embodiment of the present invention.

FIG. 3 is a cross-sectional view of a conventional green sheet laminate and an alumina setter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Setter used for this invention 2 Green sheet laminated body 3 Alumina setter used for the conventional manufacturing method 4 Pores

Claims (4)

[Claims] 1. A method of manufacturing a ceramic substrate, comprising: setting a ceramic setter and a green sheet on top of each other and firing at 800 ° C. to 1000 ° C., wherein the porosity of the ceramic forming the setter is 40% to 80%. % Of the ceramic substrate. 2. The method according to claim 1, wherein the green sheet has a laminated structure. 3. The setter has a specific heat of 4.2 kJ / (k).
The method for producing a ceramic substrate according to claim 1, wherein the method comprises g · K) or less. 4. The method of manufacturing a ceramic substrate according to claim 1, wherein a plurality of said setters and said green sheets are stacked and fired simultaneously.