JPH08125339A - Manufacture of multilayer circuit board - Google Patents

Abstract

PURPOSE: To provide a method for manufacturing a multilayer circuit board in which an electronic component such as a semiconductor element, a capacitor, a resistor can be accurately and rigidly placed to be connected by flattening the outer surface. CONSTITUTION: A method for manufacturing a multilayer circuit board comprises the steps of laminating a plurality of green sheets 10a, 10b, 10c having a wiring conductor pattern 20 on the surface and filled with conductive paste 21 in a through hole (a), and baking it at a high temperature whereby the paste 21 to be filled in the hole (a) is formed by adding 90.0 to 99.0wt.% of copper powder, 1.0 50 10.0wt.% of silicon oxide powder, organic solvent and solvent.

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 multilayer wiring board used for a package for housing semiconductor elements, a hybrid integrated circuit board and the like.

[0002]

2. Description of the Related Art Conventionally, a multilayer wiring board used for a package for housing a semiconductor device, a hybrid integrated circuit board, etc. has a high melting point of tungsten, molybdenum, manganese, etc. in and on an insulating substrate made of an aluminum oxide sintered body. A wiring conductor made of metal powder is deposited and formed, and such a conventional multilayer wiring board is generally manufactured by employing a thick film forming technique such as a ceramics laminating technique and a screen printing method described below. .

That is, (1) First, an organic solvent and a solvent are added to and mixed with a ceramic raw material powder such as alumina (Al ₂ O ₃ ), silica (SiO ₂ ), calcia (CaO), and magnesia (MgO) to prepare a plurality of sheets. And a through hole is formed at a predetermined position of each ceramic green sheet.

(2) Next, a conductive paste obtained by adding and mixing an organic solvent and a solvent to a refractory metal powder of tungsten, molybdenum, manganese or the like is mixed on the surface of each of the ceramic green sheets with a conventionally known screen printing method or the like. By applying the thick film forming technology of
A wiring conductor pattern is formed and a conductive paste is filled in the through holes provided in each ceramic green sheet.

(3) Finally, the respective ceramic green sheets are laminated so that the upper and lower wiring conductor patterns are electrically connected by the conductive paste filled in the through holes, and these are laminated in a reducing atmosphere at a temperature of about 1500 ° C. And a wiring conductor made of tungsten, molybdenum, manganese, or the like is attached to the inside and the surface of the insulating base made of an aluminum oxide sintered body to form a multilayer wiring board.

[0006]

However, in this conventional multilayer wiring board, the electrical resistance value of tungsten, molybdenum, etc. forming the wiring conductor is high, so that the voltage drop of the electric signal transmitted through the wiring conductor is large, and therefore the wiring is The conductor cannot be made fine and the wiring board cannot be made compact and high-density.

Since the relative permittivity of the aluminum oxide sintered body forming the insulating base is as high as 9 to 10 (room temperature 1 MHz), the propagation speed of the electric signal transmitted through the wiring conductor provided on the insulating base is low, and therefore the electric signal A semiconductor element or the like that requires high-speed propagation cannot be accommodated or mounted. It had a defect such as.

In order to solve the above-mentioned drawbacks, therefore, there has been proposed a multilayer wiring board in which the insulating substrate is made of a glass ceramic sintered body having a low relative dielectric constant and the wiring conductor is made of copper having a low electric resistance value. .

A multilayer wiring board using such a glass-ceramics sintered body as an insulating base is a multilayer wiring board in which a wiring conductor made of tungsten, molybdenum, or the like is attached to the inside and the surface of the insulating base made of the aluminum oxide sintered body. Substantially the same method as a wiring board, that is, an organic solvent and a solvent are added to and mixed with glass ceramic powder obtained by adding an inorganic filler to glass to obtain a plurality of green sheets, and through holes are formed at predetermined positions of each green sheet. Formed,
Next, on the upper surface of each green sheet, a copper paste obtained by adding and mixing ethyl cellulose or acrylic resin and a solvent such as alpha terpineol to copper powder is printed and applied in a predetermined pattern by a screen printing method to form a wiring conductor pattern. In addition, the copper paste used when forming the wiring conductor pattern is filled in the through holes provided in each green sheet, and thereafter, the copper paste in which the wiring conductor patterns above and below each green sheet are filled in the through holes It is manufactured by stacking so as to be electrically connected with each other and firing it at a temperature of about 900 ° C. in a reducing atmosphere.

However, a multilayer wiring board in which a wiring conductor made of copper is laminated in multiple layers inside and on the surface of an insulating substrate made of this glass-ceramics sintered body has a thermal contraction rate of a copper sheet of a green sheet made of glass-ceramics. Because of the large thermal shrinkage of the copper paste in the through-holes, when the green sheets are stacked and fired, the copper paste filled in the through-holes shrinks as the green sheet shrinks. It is pushed out in the axial direction, and as a result, large irregularities are formed on the outer surface of the multilayer wiring board, which is greatly deformed, which causes a drawback that mounting and connection of semiconductor elements, capacitors, resistors, etc. becomes difficult.

[0011]

SUMMARY OF THE INVENTION The present invention has been devised in view of the above-mentioned drawbacks, and its object is to provide a multilayered structure in which electronic components such as semiconductor elements, capacitors and resistors can be mounted accurately and firmly by connecting the outer surface to a flat surface. It is to provide a method for manufacturing a wiring board.

[0012]

Means for Solving the Problems A method for manufacturing a multilayer wiring board according to the present invention is a green formed into a sheet by adding an organic solvent and a solvent to a glass ceramic powder formed by adding an inorganic filler to borosilicate glass. A step of preparing a sheet and forming a through hole in the green sheet; a step of forming a wiring conductor pattern on the surface of the green sheet and filling a conductive paste in the through hole; and a plurality of the green sheets Stacked
A method for manufacturing a multilayer wiring board in which the wiring conductor pattern on the surface of each green sheet is electrically connected with a conductive paste filled in the through hole of each green sheet and is baked at a high temperature. The conductive paste to be filled is formed by adding an organic solvent and a solvent to 90.0 to 99.0% by weight of copper powder and 1.0 to 10.0% by weight of silicon oxide powder.

Further, the present invention is characterized in that aluminum oxide powder is further added to the conductive paste so that the total amount of the silicon oxide powder and the aluminum oxide powder is 1.5 to 10.0% by weight and 6.0% by weight or less by external addition. It is what

[0014]

According to the method for manufacturing a multilayer wiring board of the present invention, the conductive paste is made of copper powder 90.0 to 99.0% by weight and silicon oxide powder.
It was formed by adding an organic solvent and a solvent to 1.0 to 10.0% by weight, and its heat shrinkage was adjusted to be substantially the same as the heat shrinkage of a green sheet made of glass ceramic powder obtained by adding an inorganic filler to borosilicate glass. Therefore, when the conductive paste is filled in the through holes of the green sheet and a plurality of these are stacked and fired, the thermal contraction rates of the green sheet and the conductive paste are substantially the same, so the conductive paste filled in the through holes Is not extruded significantly in the axial direction of the through hole due to the shrinkage of the green sheet, and as a result, there is no large unevenness formed on the outer surface of the multilayer wiring board, and the surface is always flat. Electronic components such as capacitors and resistors can be mounted accurately and firmly and connected.

[0015]

The present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 shows an embodiment of a multilayer wiring board manufactured by the manufacturing method of the present invention, where 1 is an insulating substrate and 2 is a wiring conductor.

The insulating substrate 1 is made of a glass ceramics sintered body, for example, 72.0 to 76.0% by weight of silicon oxide, 1
Borosilicate glass consisting of 5.0-17.0% by weight of boron oxide, 1.5% by weight or less of manganese oxide, 1.1-1.4% by weight of zirconium oxide and total amount of 2.0-3.0% by weight of lithium oxide, potassium oxide and sodium oxide. 18.0 ~ 24.0wt% alumina as filler, 8.0 ~ 17.0wt%
Silicon oxide of 13.0 to 25.0% by weight of cordierite is added.

Wiring conductors 2 are multi-layered on the inside and the surface of the insulating base 1, and the insulating base 1 functions as a supporting member for supporting the wiring conductor 2.

Since the insulating base 1 has a low relative dielectric constant of 6.5 (room temperature 1 MHz) in the glass-ceramic sintered body constituting the insulating base 1, the wiring conductor 2 adhered to the inside and the surface of the insulating base 1 is low. The propagation speed of the electric signal transmitted is high, and as a result, it is possible to accommodate and mount the semiconductor element that requires high-speed propagation of the electric signal in the insulating base 1.

Further, the insulating substrate 1 made of the glass-ceramics sintered body has a coefficient of thermal expansion of 3.5 × 10 ⁻⁶ / ° C. to 5.0.
× 10 ^-6 / ℃, which is close to the thermal expansion coefficient of silicon (3.0 × 10 ^-6 / ℃ ~ 3.5 × 10 ^-6 / ℃) that composes the semiconductor element, so the semiconductor element is mounted on the insulating substrate 1. After that, even if heat generated during the operation of the semiconductor element is applied to both the insulating substrate 1 and the semiconductor element, a large thermal stress does not occur between them, and as a result, the semiconductor element is damaged by the thermal stress. And the semiconductor element is not peeled off from the insulating substrate 1.

The insulating base 1 made of the above-mentioned glass-ceramics sintered body has a plurality of wiring conductors 2 made of copper deposited on the inside and the surface thereof, and the wiring conductors 2 are made of the insulating base 1.
The electronic components 3 such as semiconductor elements, capacitors, and resistors mounted on the surface of the electronic components are electrically connected to each other, and also serve as conductive paths when the electronic components 3 are connected to an external electric circuit.

Since the wiring conductor 2 made of copper has a low electric resistance value of copper, the voltage drop of the electric signal transmitted through the wiring conductor 2 is made extremely small, and the wiring conductor 2 is miniaturized to reduce the size of the wiring board. It can sufficiently deal with densification.

Next, a method of manufacturing the above-mentioned multilayer wiring board will be described with reference to FIGS. 2 (a) to 2 (c).

First, as shown in FIG. 2A, three green sheets 10a, 10b and 10c are prepared and through holes a are formed at predetermined positions of the green sheets 10a and 10b.

The green sheets 10a, 10b and 10c are, for example, 72.0 to 76.0% by weight of silicon oxide and 15.0 to 17.0% by weight.
Boron oxide, 1.5% by weight or less of manganese oxide, 1.1 ~
Borosilicate glass consisting of 1.4 wt% zirconium oxide and total amount of 2.0-3.0 wt% lithium oxide, potassium oxide, sodium oxide, 18.0-24.0 as an inorganic filler.
Wt% alumina, 8.0-17.0 wt% silicon oxide, 13.0
Formed by adding glass-ceramic powder containing ~ 25.0% by weight cordierite to an organic solvent and solvent to form a slurry and molding it into a sheet by the conventionally known doctor blade method or calender roll method. To be done.

The through holes a of the green sheets 10a and 10b are formed at predetermined positions of the green sheets 10a and 10b by forming through holes having a predetermined diameter in the green sheets 10a and 10b by a conventionally known press punching method. To be done.

Next, as shown in FIG. 2B, the wiring conductor pattern 20 is applied to the surface of each of the green sheets 10a, 10b, 10c, and at the same time, the conductive paste 21 is filled in the through holes a.

The wiring conductor pattern 20 is formed by, for example, screen-printing a copper paste obtained by adding and mixing ethyl cellulose or acrylic resin and a solvent such as alpha-terpineol to copper powder to the surface of each green sheet 10a, 10b, 10c. The green sheets 10a, 10b, 10c are adhered to the surfaces of the green sheets 10a, 10b, 10c by printing and applying a predetermined pattern.

The conductive paste 21 filled in the through holes a of the green sheets 10a and 10b is copper powder 90.0.
To 99.0% by weight, silicon oxide powder 1.0 to 10.0% by weight,
The green sheet 10a is formed by adding and mixing a cellulose resin or an acrylic resin and a solvent such as dibutyl phthalate, terpineol, butyl carbitol acetate, etc., and adopting a conventionally known screen printing method or the like.
, 10b are filled in the through holes a.

The conductive paste 21 filled in the through holes a of the green sheets 10a and 10b has a heat shrinkage rate of each of the green sheets 10a and 10b by setting the amounts of the copper powder and the silicon oxide powder within a predetermined range. , 10c are adjusted to be substantially the same for the heat shrinkage.

The conductive paste 21 filled in the through-hole a contains copper powder and silicon oxide powder, respectively.
When it goes out of the range of 90.0 to 99.0% by weight and 1.0 to 10.0% by weight, the heat shrinkage rate of the conductive paste 21 is decreased in each green sheet 10a.
, 10b and 10c are different from each other,
As a result, each green sheet 10a, 10b, 10c described later
When laminated and fired, the conductive paste 21 filled in the through holes a is extruded in the axial direction of the through holes a as the green sheets 10a, 10b, 10c shrink, resulting in large irregularities on the outer surface of the multilayer wiring board. Will be formed. Therefore, the conductive paste 21 filled in the through hole a
The amounts of copper powder and silicon oxide powder are 90.0 to 99.0, respectively.
% By weight, specified in the range 1.0 to 10.0% by weight.

Further, in the conductive paste 21, if the average particle size of the copper powder constituting the conductive paste 21 is set in the range of 1.0 to 10.0 μm and the average particle size of the silicon oxide powder is set in the range of 1.0 to 5.0 μm, the respective green sheets 10a, 10b. When the conductive paste is filled in the through hole a provided in the above by the printing method, the filling property becomes extremely good. Therefore, the conductive paste 21 preferably has an average particle size of copper powder in the range of 1.0 to 10.0 μm and an average particle size of silicon oxide powder in the range of 1.0 to 5.0 μm.

Next, as shown in FIG. 2C, the green sheets 10a, 10b and 10c having the wiring conductor pattern 20 deposited on the surface and the conductive paste 21 filled in the through holes a are shown in FIG. The wiring conductor pattern 20 adhered to the surfaces of 10a, 10b, 10c is laminated up and down so as to be electrically connected by the conductive paste 21 filled in the through holes a of the green sheets 10a, 10b. To form.

Finally, the laminated body L is fired at a temperature of about 900 ° C. in a reducing atmosphere to obtain each green sheet 10a.
, 10b, 10c, wiring conductor pattern 20 and through hole a
By sintering and integrating the conductive paste 21 filled in the inside, the multilayer wiring board as a product in which the wiring conductor 2 is adhered to the inside and the surface of the insulating substrate 1 made of the glass ceramics sintered body shown in FIG. Complete. In this case, the thermal contraction rate of the conductive paste 21 filled in the through holes a of the green sheets 10a, 10b is set to the respective green sheets 10a, 10b, 10c.
Therefore, the conductive paste 21 filled in the through-hole a is substantially extruded in the axial direction of the through-hole a as the green sheets 10a, 10b, 10c shrink. As a result, no large irregularities are formed on the outer surface of the multilayer wiring board, and it is always flat, and electronic components such as semiconductor elements, capacitors, and resistors can be mounted accurately and firmly on the surface. Becomes

The present invention is not limited to the above-mentioned embodiments, and for example, in the above-mentioned embodiments, each green sheet is used.
Wiring conductor pattern to be attached to the surface of 10a, 10b, 10c
Although 20 is formed of a copper paste different from the conductive paste 21 filled in the through holes of each green sheet 10a, 10b, it may be formed of the same conductive paste 21 filled in the through holes a. Good. In this case, since the wiring conductor pattern 20 is formed of the same material as the conductive paste 21 filled in the through hole a, the wiring conductor pattern 20 is formed.
There is no need to separately prepare a paste for forming 20.

Further, in the above embodiment, the conductive paste 21 filled in the through hole a is made of copper powder 90.0 to 99.0% by weight,
It was formed by adding 1.0 to 10.0% by weight of silicon oxide powder to a cellulose resin or acrylic resin and a solvent such as dibutyl phthalate, terpineol, butyl carbitol acetate, etc., and further adding aluminum oxide powder to the silicon oxide powder. The total amount of powder and aluminum oxide powder is 1.
6.0 wt% by external addition to make it 5 to 10.0 wt%
If added below, the conductive paste 21 filled in the through hole a and the green sheets 10a and 10b will be completely sintered and integrated, and the adhesion strength between both will be stronger.
Therefore, the conductive paste 21 filled in the through hole a is further added with aluminum oxide powder such that the total amount of the silicon oxide powder and the aluminum oxide powder is 1.5 to 10.0% by weight and 6.0% by weight or less by external addition. Preferably.

Further, in the above-mentioned embodiment, three green sheets are laminated to manufacture a multilayer wiring board, but this is manufactured by laminating four or more green sheets or laminating two green sheets. Good.

[0037]

According to the method for manufacturing a multilayer wiring board of the present invention, a conductive paste is formed by adding 90.0 to 99.0% by weight of copper powder and 1.0 to 10.0% by weight of silicon oxide powder with an organic solvent and a solvent. The heat shrinkage was adjusted to be substantially the same as the heat shrinkage of the green sheet made of glass-ceramic powder obtained by adding inorganic filler to borosilicate glass. When laminated and fired, the thermal contraction rates of the green sheet and the conductive paste are substantially the same, so the conductive paste filled in the through-holes is greatly extruded in the axial direction of the through-holes as the green sheet shrinks. As a result, no large irregularities are formed on the outer surface of the multilayer wiring board and the surface is always flat. It becomes possible to mount electronic components such as capacitors, resistors, etc. accurately and firmly and connect them.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a multilayer wiring board manufactured by a manufacturing method of the present invention.

2A to 2C are cross-sectional views in each step for explaining a method of manufacturing the multilayer wiring board shown in FIG.

[Explanation of symbols]

1 ・ ・ ・ ・ ・ ・ Insulating substrate 2 ・ ・ ・ ・ ・ ・ Wiring conductor 3 ・ ・ ・ ・ ・ ・ Electronic parts 10a, 10b, 10c ・ ・ ・ ・ Green sheet 20 ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ Wiring conductor pattern 21 ・ ・ ・ ・ ・ ・ ・ Conductive paste filled in the through hole a ・ ・ ・ ・ ・ ・

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location H05K 3/40 K 7511-4E

Claims (2)

[Claims] 1. A step of preparing a sheet-shaped green sheet by adding an organic solvent and a solvent to a glass-ceramic powder obtained by adding an inorganic filler to borosilicate glass to prepare a green sheet and forming a through hole in the green sheet. And a step of depositing a wiring conductor pattern on the surface of the green sheet and filling a conductive paste in the through holes, and stacking a plurality of the green sheets to form a wiring conductor pattern on the surface of each green sheet. A method for manufacturing a multilayer wiring board in which the conductive paste filled in the through holes is electrically connected and baked at a high temperature, wherein the conductive paste filled in the through holes of the green sheet is copper powder 90.0 to 99.0 wt. %, Silicon oxide powder 1.
A method for manufacturing a multilayer wiring board, which is characterized by being formed by adding an organic solvent or a solvent to 0 to 10.0% by weight. 2. An aluminum oxide powder is further added to the conductive paste, and the total amount of the silicon oxide powder and the aluminum oxide powder is
2. The method for manufacturing a multilayer wiring board according to claim 1, wherein the external addition amount is 6.0 wt% or less so that the content is 1.5 to 10.0 wt%.