JPS5816596A - High density multilayer circuit board - 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 The present invention provides a high-density multilayer wiring board, 411, a high-density multilayer wiring board with external terminal bins, which has low electrical resistance of wiring patterns and low capacitance between signal lines and power sources, and has good dimensional accuracy. Regarding the structure of

In recent years, with the development of electronic computers, there has been an increasing demand for improved calculation speed and higher density in high-speed calculation circuits.

In order to meet this requirement, multilayer wiring boards with multiple layers of signal lines are used. It is necessary to achieve a reduction in In addition, the multilayer wiring board, in which integrated circuits are mounted on the multilayer wiring board at high density, needs to have a large number of external terminals.

If such a multilayer wiring board can be constructed from a multilayer ceramic board using the green sheet method using heat-resistant metals such as Mo (molybdenum) and W (tungsten) as conductor layers, the Because the dielectric constant is large (S
8~ with 2% alumina substrate! l) It is not possible to lower the capacitance between the signal line and the power supply. First, heat-resistant metals such as Mo%W have the disadvantage of extremely high electrical resistance.For example, compared to the specific resistance of steel x,yxlo'o·m (at 20°C), M.

at 5.6X1 (r'Ω・1 (20℃), W at s, 5xt
r”Ω・cx (20℃). Moreover, K MQ , Y
Since it is easily oxidized, it cannot be exposed to actual temperature in the air, and the shrinkage rate during baking is difficult to control, resulting in poor dimensional accuracy.

It is an object of the present invention to eliminate such drawbacks, reduce the electric resistance of the signal line and the electric capacitance between the signal line and the power source, and form external terminal bins on the entire back surface of the board main body to connect a large number of external terminals. There are several companies that provide high-precision multilayer wiring boards with good dimensional accuracy that allow connection of terminal tangents.

For this purpose, the high-density multilayer wiring board according to the present invention is
't (Chisso) is applied to the surface of the multilayer ceramic substrate body, which has a heat-resistant metal such as MO%W as a conductive layer on the surface and inner layers.
- Inorganic paste for insulating layer F1 resistor paste made of 1K Cu (copper) conductor, low dielectric constant glass or a mixture of glass and ceramic which can be fired in an atmosphere 2) Wiring island signal lines are multilayered using a photolithographic method, and a plurality of vias as external terminals are formed on the back surface of the substrate body.

Hereinafter, the present invention will be described by way of embodiments with reference to the drawings.

FIG. 1 is a schematic longitudinal sectional view of a multilayer wiring board according to a first embodiment of the present invention. green? - W as the inner layer pattern of the IL of the main body of the multilayer ceramic substrate manufactured using the method
It has a first power supply layer 2 and an II2 power supply layer 3 which are conductors, and has a signal line through via 4 and a power supply through via 5 which reach from the front surface to the back surface of the substrate main body. The power supply through via 5 is connected to the power supply pattern of each power supply layer 2.3 as shown by reference numeral 6. On the front surface of the board main body 10, there are soldered pads 8 for connection to the upper forming pattern, and on the back surface, external terminal pins 14 are soldered via mounting pads 7, as shown by reference numeral 13. Furthermore, the surface of the board body 10 has C
Pattern U paste using thick film printing method and make it summer!
There is a 90μ wiring pattern 9 formed by firing in an atmosphere or by a plating method, and between the layers of this wiring pattern, a thick film is formed using an insulating paste for firing in an atmosphere. M made into a pattern using the seal method or photolithographic method.

There is an insulating layer 12 fired in an atmosphere, and furthermore, an IC lead pond pad 11 and a die pad 10 for mounting an ICC are provided on the uppermost surface thereof. FIG. 2 shows a state in which the 1fCXC15 is mounted on the high-density multilayer wiring board of the embodiment shown in FIG. 11. This is the lead with the code 16 wire C15.

FIG. 3 is a longitudinal sectional view of a multilayer wiring board showing a second embodiment of the present invention. In this embodiment, N! is further formed on the multilayer wiring board of the first embodiment by firing in an atmosphere to form 90μ resistor electrodes 17, 18 and N! - It has a circular configuration and has a resistor 19 formed from a resistor paste for atmosphere firing. FIG. 4 shows an example in which XCl3 is mounted on the high-density multilayer wiring board with resistors of the second embodiment shown in FIG.

As explained above, the present invention uses a Cu wiring pattern and an insulating layer with a low dielectric constant on the surface of a multilayer ceramic substrate that has a W conductor that easily oxidizes in the air and has poor dimensional accuracy, thereby reducing the dimensional accuracy of the thick film. By patterning using a printing method or an otolithographic method and complementing the multilayer wiring by baking in an atmosphere, the wiring pattern has good dimensional accuracy, the electrical resistance of the wiring pattern and the electrical capacitance between the signal line and the power supply are low, and This has the effect of providing a high-density multilayer wiring board having a large number of external terminal bins on the back surface of the main body.

[Brief explanation of the drawing]

1 and 2 are longitudinal cross-sectional views of a high-density multilayer wiring board according to one embodiment of the present invention, and FIG. 3 and sheath 4 are longitudinal cross-sectional views showing other embodiments of the present invention. . DESCRIPTION OF SYMBOLS 1...Multilayer ceramic board main body, 2...1st power layer, 3...2nd power layer, 4...
...Through via for signal line, 5...Through via for power supply, 9...Cu wiring pattern, 12...Inorganic insulation layer made of insulating paste for h atmosphere firing, 14...Bin/substitute for external terminal People Patent Attorney Rikichi Somekawa

Claims (1)

[Claims] A copper conductor and an inorganic insulating layer with low electrical conductivity are arranged on both surfaces of a multilayer laminated laminated board main body having heat-resistant metal as a conductive layer on the surface and inner layers to form a multilayer signal line, and a multilayer signal line is formed on the back surface of the board main body. A high-density multilayer wiring board characterized by being able to provide a plurality of external terminal bins.