JPS6122692A - Multilayer circuit board and method of producing same - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical field to which the invention pertains] The present invention relates to a multilayer wiring board and a method for manufacturing the same. [Prior art] Conventionally, a ceramic board having through-hole wiring that penetrates the front and back of the board has been manufactured using an alumina green sheet. It is formed using Therefore, since a sintering temperature of 1,400°C or higher is required, it is necessary to use high-melting point metals such as tungsten and molybdenum as conductive materials. High specific electrical resistance. Therefore, there is a problem in that it is difficult to reduce the power supply wiring resistance inside the ceramic substrate.

Furthermore, when attempting to form a multilayer wiring on a solid ceramic substrate, tungsten or molybdenum becomes unusable as a conductive layer due to oxidation when sintered in air at a temperature of 1400° C. or higher.

Therefore, there are significant restrictions on the process and materials for multilayer wiring. Normal thick film paste material is 800~900℃
Because it is used in air firing, it cannot be used in combination with this ceramic substrate. In particular, when attempting to form fine, high-density multilayer wiring, a photocurable insulating paste is desirable as the insulating material. However, since this paste must be fired at a temperature of 400'C or higher in an air atmosphere, it cannot be used in combination with this ceramic substrate.

[Purpose of the invention]

The purpose of the present invention is to enable the use of materials that can withstand firing in air, such as gold and silver/palladium alloys, as the conductor material inside the board and the conductor material of the multilayer wiring layer, and to realize power supply wiring with optimal impedance. It is an object of the present invention to provide a multilayer wiring board and a method for manufacturing the same, which enable high-density multilayer wiring without being subject to significant restrictions on materials or processes.

[Structure of the invention]

To explain the structure of the present invention, first, the multilayer wiring board according to the first invention includes a power supply wiring layer and through-hole wiring that penetrates the front and back of the board, and can be sintered in air at a temperature of 1400°C or higher. and a multilayer wiring layer formed on the surface of the substrate and including an inorganic insulating layer sintered using a photocurable insulating paste material. .

The conductive material for the power wiring layer and through-hole wiring in the glass ceramic substrate is gold, silver-palladium alloy, or the like.

Further, the second invention, which is a method for manufacturing the above-mentioned multilayer wiring board, includes a green sheet-like multilayer board containing a power supply wiring layer and through-hole wiring that penetrates the front and back of the board.
a first step of forming a glass ceramic substrate by sintering in air at a temperature of 0.degree. C. or lower; a second step of forming a conductor wiring layer on the surface of the glass ceramic substrate; The present invention is characterized by comprising a third step of forming an inorganic insulating layer using a photocurable insulating paste material so as to cover a desired portion and a desired portion of the conductive wiring layer.

[Explanation of Examples]

FIG. 1 shows a wiring board 1400 constituting a multilayer wiring board according to the present invention.
FIG. 2 is a diagram showing a glass ceramic substrate that can be sintered at a low temperature of .degree. C. or lower. In FIG. 1, 1 is a glass ceramic substrate, 101 is a first power wiring layer, 102 is a second power wiring layer, 103 is a surface layer, 104 is a terminal, 105 is a first through-hole wiring, and 106 is a first power wiring layer. 2 through-hole wiring, 1
07 is the third through-hole wiring, 108 is the surface exposed part of the through-hole wiring, and 109, 110.111
1 and 2 respectively show green sheets laminated in the process of manufacturing the glass ceramic substrate 1t.

The glass ceramic substrate 1 shown in FIG.
It is made of the inorganic composition according to the invention of No.-17474 and can be sintered in air at a low temperature of 1400°C or lower. That is, the green sheet 1 made of the inorganic composition
Holes for through-hole wirings 105, 106 and 107 are punched in holes 09, 110 and 111, respectively. The punched through holes in each sheet are then filled with a thick film conductor paste based on gold or a silver-palladium alloy by printing. Furthermore, the first power layer 101 is printed on the front surface of the green sheet 1090, and pads for forming terminals 104 are printed on the back surface. In addition, a second power supply wiring layer 10 is formed on the plane of the green sheet 1100.
2 is printed on the 0th order, green sheets 109 to 111
After alignment, each layer is laminated, and each layer is pressed together using a press. Thereafter, this green sheet laminate is fired in air at 700°C to 900°C. Through this process, each green sheet 109-111. is integrated with the ceramic substrate 1, and each conductor base (
* is fired to become power supply wires N101, 102 and through-hole wirings 105, 106 and 107. terminal 1
Mutual electrical connections are made between each of the power supply terminals 04 and each power supply wiring layer, and electrically conductive connection is made between each of the terminals 104 and the exposed surface portion of the through-hole wiring.

On the surface of the ceramic substrate 1 obtained in this way,
Through-hole wiring 1070 surface exposed portion 108 is formed. However, since the through-hole wiring 107 is simply filled with conductive paste, printed, and fired as described above, its surface is extremely uneven. Therefore, it is necessary to polish the surface of the ceramic substrate 10 after firing. As a result, irregularities on the surface of the substrate including through-hole wiring become smooth, making it easier to form signal wiring on the surface of the substrate, which will be described below.

Referring to FIG. 2, a wiring layer 2 using an inorganic thick film insulation formed of a photocurable insulation paste is formed by a first inorganic insulation layer 2.
01, second inorganic insulating layer 202, first via hole wiring 2
03, first wiring layer 204, second guiahole wiring #205
, a second wiring layer 206, and a third wiring layer 207. The inorganic thick film wiring layer 2 has signal wiring for interconnecting a plurality of IC chips mounted on its surface and a plurality of IC chips mounted on the surface thereof.
Signal and power terminals of the chip and terminals 104 of the multilayer wiring board
It is formed on the surface of the ceramic substrate 1 for connection to the ceramic substrate 1.

The first via hole 203 is provided to connect each of the wirings in the first wiring M2O4 and each of the wirings in the second wiring 206. 2nd via hole wiring 2
05 are provided to connect each of the second wirings 206 and each of the third wirings 207. The first wiring 204 connects each of the exposed portions 108 of the through-hole wiring of the ceramic substrate 1 and each of the first via-hole wirings 203 .

The inorganic wiring layer uses a photocurable insulating paste material and wiring material that can be fired in air at 700°C to 900°C. This is possible for the following reason. That is,
Printing a high melting point metal conductor such as tungsten on a conventional alumina green sheet and heating it to 1400℃~1500℃
Ceramic substrates that are fired in a reducing atmosphere have wiring made of materials that easily oxidize, such as tungsten and molybdenum, so it is not possible to form an air-fired insulating layer or interconnection layer on the board after sintering. is impossible. However, when the glass-ceramic substrate according to the present invention is used as a base material, the substrate itself is fired in air at 700°C to 900°C as described above, so the insulating layer and wiring are then heated in the same atmosphere. It is possible to add layers.

Now, in the multilayer wiring board according to the present invention, the signal wiring is formed by thin film technology. The reason for this is that thin film wiring allows finer wiring to be formed than thick film wiring, and therefore the required number of wiring can be accommodated with a smaller number of wiring layers.

As an example, the thin film wiring is obtained by forming a base metal thick film of Ti and Pd on the substrate by sputtering, and then forming it on the photo ring 2 using a gold wiring plating technique. Such wiring can use a material with low electrical resistance, such as gold, that does not oxidize when fired in air, so it has the advantage of lowering the time constant of the wiring and shortening the signal propagation time.

In order to take advantage of such advantages of thin film wiring technology, the peer holes in the insulating layer must also be miniaturized at the same time. In the present invention, a photocurable insulation paste material is used for this purpose. If this material is used, the formation of pier holes can be performed by photolithography technology, so it is possible to form pier holes that are 1/4 to 115 times smaller in size than normal screen printing. In order to completely remove the photosensitive component used in the photocurable insulation paste, baking in air is necessary, but this is not possible in this example because gold or silver/palladium alloy is used as the conductor material. It is possible.

〔Effect of the invention〕

According to the present invention, a multilayer wiring layer is formed using a photo-effective insulating paste material on the surface of a glass ceramic substrate that includes a conductive layer inside and can be fired in low temperature air.
It is possible to use materials that can withstand firing in air, such as gold or silver/palladium alloys, as the conductor material inside the board or the conductor material of the multilayer wiring layer. Effects such as high-density multilayer wiring are possible without being subject to significant restrictions on materials or processes.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which FIG. 1 is a perspective view of a part of a glass ceramic substrate in cross section, and FIG. 2 is a cross sectional view of a multilayer wiring board. 1...Glass ceramic substrate, 2...
Inorganic multilayer wiring layer, 101...first power supply wiring layer...
102゛...Second power wiring layer, 104...Terminal,
105...First through-hole wiring, 106.
...Second through hole arrangement, 107...
- Third through-hole wiring, 108... through-hole wiring surface exposed portion, 201... first inorganic insulating layer, 202... second inorganic insulating layer, 203...・
... 1st via hole wiring, 204 ... - 1st
Thin film wiring layer, 205... Second via hole latitude line, 206... Second thin film wiring layer, 207...
・'Third wiring layer. No. 21￥I

Claims (3)

[Claims] (1) A glass-ceramic substrate that includes a power supply wiring layer and through-hole wiring that penetrates the front and back sides of the substrate and can be sintered in air at a temperature of 1400°C or less, and a photocurable material formed on the surface of this substrate. A multilayer wiring board comprising a multilayer wiring layer including an inorganic insulating layer sintered using an insulating paste material. (2) The multilayer wiring board according to claim 1, wherein gold or a silver-palladium alloy is used as a conductive material for the power supply wiring layer and through-hole wiring in the glass ceramic substrate. (3) 14 green sheet-like laminated boards containing a power supply wiring layer and through-hole wiring that penetrates the front and back of the board.
A first step of forming a glass ceramic substrate by sintering in air at a temperature of 00° C. or lower, a second step of forming a conductor wiring layer on the surface of the glass ceramic substrate, and a desired surface of the glass ceramic substrate. and a third step of forming an inorganic insulating layer using a photocurable insulating paste material so as to cover a desired part of the conductive wiring layer.