JPH05191047A - Manufacture of multilayer ceramic circuit board - Google Patents

Abstract

PURPOSE:To eliminate voids on the peripheries of conductor lines and to prevent an interlayer separation from being generated by a method wherein the conductor lines are adhered on a carrier film, a slurry is applied to dry the lines, a green sheet provided its lower part with the conductor lines is formed and the green sheet is laminated on a green sheet with the conductor lines buried therein, is pressed, is formed integrally with the green sheet with the lines buried therein and is subjected to firing. CONSTITUTION:A green sheet 8 with conductor lines 2 buried previously therein is used. Here, as the material for the lines 2, a metal foil of a thickness of 30mum or thereabouts is previously punched out or is subjected to photo-etching and the metal foil formed by patterning is used. A green sheet is formed by a doctor blade method in a state that the lines 2 consisting of this metal foil are adhered on a carrier film, whereby the green sheet with the lines 2 buried therein can be formed. That is, when a green sheet 9 is positioned and abutted on the sheet 8 with the lines 2 buried therein, is pressed and is formed integrally with the sheet 8, voids on the peripheries of the lines 2 can be eliminated and by heating this sheet 9, a ceramic circuit board with good characteristics can be manufactured.

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 multi-layer ceramic circuit board which has no voids around a conductor line and has improved performance and reliability.

Semiconductor devices such as LSIs and VLSIs, which occupy the main body of information processing devices, generate a large amount of heat due to their improved degree of integration, and therefore, multilayer circuit boards are constructed using ceramics with excellent heat resistance. An electronic circuit is made by mounting a large number of semiconductor elements in a matrix on this substrate.

[0003]

2. Description of the Related Art As a method for manufacturing a multilayer ceramic circuit board, a powder made of glass ceramics or alumina ceramics is mixed with an organic binder, a plasticizer, an organic solvent, etc. to make a slurry, which is made of a polymer by a doctor blade method. Is applied to a uniform carrier film to a certain thickness and dried to form a green sheet.

Next, after punching holes at required positions of the green sheet cut into a certain size, the holes are filled with a conductor paste to form via holes. next,
After printing a conductor line on the surface of this green sheet by screen printing and drying, stacking this green sheet while aligning it, pressurizing it to integrate it, and firing it in a non-oxidizing atmosphere. A multilayer ceramic circuit board is made.

Here, the thickness of the conventional green sheet is generally about 300 μm, and the thickness of the conductor line is 30 to 50.
Those of about μm were used. However, because it is necessary to reduce the size and performance of information processing devices, it is necessary to reduce the thickness of multilayer ceramic circuit boards.Therefore, the thickness of the green sheets that form the unit layers should be reduced to 100 μm or less. ing.

On the other hand, regarding wiring patterns, LSI and VLSI
Since it is necessary to secure a current capacity for driving the green sheet, it cannot be thinned in accordance with the thinning of the green sheet.
FIG. 3 is a sectional view showing a conventional manufacturing method.

That is, as shown in FIG. 1A, a conductor line 2 made of a conductor paste is formed on a green sheet 1, on which a green sheet 3 is positioned, laminated and pressed. However, in this case, since the green sheets 1 and 3 are thick and soft to some extent, the conductor line 2 can be embedded in the green sheets 1 and 3 by pressurization, and a dense circuit can be formed by firing the green sheets 1 and 3. The substrate has been obtained.

However, as shown in FIG. 2B, when the green sheets 4 and 5 become thin, it is impossible to absorb the thickness of the conductor line 2 due to the deformation of the green sheets 4 and 5 during pressurization. Therefore, a gap 6 is formed around the conductor line 2.

For this reason, a gap is formed even after firing, which causes insulation failure between the conductor lines 2 and easily causes substrate peeling. From these things, improvement was needed.

[0010]

When forming a multilayer ceramic circuit board, the thickness of the green sheet is 100 μm.
The thickness of the conductor line is 30 to 50μ
When the thickness of the green sheet is not so different from the thickness of the green sheet, such as m, it is impossible to completely bury the green sheets in the green sheet without a gap even if the green sheets are stacked and pressed.

Therefore, a gap remains around the conductor line of the multilayer ceramic circuit board produced by firing, which causes insulation failure and peeling. Therefore, this solution is an issue.

[0012]

[Means for Solving the Problems] The above-mentioned problems are solved by applying a conductor line on which a metal foil is patterned onto a carrier film made of a polymer, applying a slurry onto the carrier film, and then drying the conductor to form a conductor. The process of making a green sheet with a line at the bottom, the process of making a via hole in this green sheet, then filling the via with conductive paste to form a via hole, and aligning and stacking this green sheet It is possible to solve the problem by configuring a method for manufacturing a multilayer ceramic circuit board, which comprises the step of applying pressure, integrating, and then firing.

[0013]

The inventor uses a conductor line which is previously buried in the green sheet because the conductor line is thick and it is impossible to bury the conductor line in the green sheet due to deformation of the green sheet. It is a thing.

In this case, the conductor line is a metal foil having a thickness of about 30 μm, which is punched or photoetched to form a pattern. The reason for this is that the type of conductor line is limited in mass production and can be formed at a relatively low cost.

Then, a green sheet in which the conductor line is buried can be produced by forming the green sheet by the doctor blade method with the conductor line made of the metal foil stuck on the carrier film.

FIG. 1 is a principle view of the present invention, in which a green sheet 9 is placed on a green sheet 8 in which a conductor line 2 is buried.
By positioning and abutting, and applying pressure to integrate them, a gap can be eliminated, and by heating this, a ceramic circuit board with excellent characteristics can be manufactured.

[0017]

EXAMPLES Example 1: A green sheet was formed using the following materials. Borosilicate glass powder (average particle size 5 μm)
・ ・ ・ 50 parts by weight Alumina powder (average particle size 5 μm)
・ ・ ・ 50 parts by weight Polyvinyl butyral (binder) ・ ・ ・ ・ ・
・ ・ ・ ・ 10 〃 Dibutyl phthalate (plasticizer)
・ ・ ・ ・ 5 〃 Acetone (solvent) ・ ・ ・ ・ ・
・ ・ ・ ・ 400 〃 was added and kneaded using a ball mill to make a slurry.

Further, a copper (Cu) foil having a thickness of 50 μm was punched out to prepare four kinds of conductor lines, and the multilayer ceramic circuit board according to the present invention was formed by the steps shown in FIG. First,
Four types of conductor lines 11 were attached on a carrier film (polyethylene terephthalate) 10 having a thickness of 100 μm.
(A in the same figure) Next, the slurry is applied onto this by the doctor blade method and then dried to obtain a green sheet 12 having a thickness of 100 μm.
Formed. (Above B in the same figure) Next, after making holes at required positions of the green sheet 12,
Via holes 13 were formed by filling a copper paste by a screen printing method. Next, four types of green sheets 12 peeled from the carrier film 10 were aligned and laminated, and laminated at 100 ° C. under the condition of 10 MPa to be integrated to obtain a laminated body 14. (The above D in the same figure) Next, this laminated body 14 was fired at 1000 ° C. in an N ₂ stream to obtain a multilayer ceramic circuit board 15. As a result of the cutting and examination of this substrate, the conductor line 11 was in close contact with the glass ceramics, and no sign of delamination was observed.

[0019]

By implementing the present invention, it is possible to manufacture a multilayer ceramic circuit board having no void around the conductor line and no delamination.

[Brief description of drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a cross-sectional view showing a manufacturing process according to the present invention.

FIG. 3 is a cross-sectional view showing a stacking process, a pressurizing process, and a baking process according to a conventional method.

[Explanation of symbols]

 1,3,4,5,8,9,12 Green sheet 2,11 Conductor line 6 Gap 10 Carrier film 13 Via hole 15 Multilayer ceramic circuit board

Claims (1)

[Claims] 1. A conductor line formed by patterning a metal foil is attached onto a carrier film made of a polymer, and a slurry is applied onto the carrier film and then dried.
A step of forming a green sheet having a conductor line at the bottom, a step of forming a via hole in the green sheet and then filling the via with a conductor paste, and aligning the green sheet. Laminating, pressurizing and integrating, and then firing, and a method for manufacturing a multilayer ceramic circuit board.