JPS60117796A - 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 of the Invention] The present invention relates to a high-speed, high-density wiring board used in computers and the like. The present invention relates to a multilayer wiring board formed with high-density wiring.

[Prior art]

Conventional boards of this type are described in the literature (Proceedings 1
982 32nd Electronic Compo
Paper written on pages 1 to 6 at n@ntsConference 'a Ceramic Cap
acitor Substrate for HLgh
5peed Switching VLSI chips
), alumina green sheets printed with thick-film conductor paste for power supply wiring and through-hole wiring are laminated and sintered to form an inorganic insulator on the surface of the multilayer ceramic substrate. After firing the layers, a signal wiring layer was formed using thin film technology.

In this substrate, alumina green sheets are laminated to form a multilayer ceramic substrate, so the firing temperature is 14
The temperature is 00°C or higher. For this reason, high melting point metals such as tungsten and molybdenum have been used for the conductor wiring inside the ceramic substrate.

However, since this type of metal has a higher specific electrical resistance than gold or copper, it is not preferred as wiring for supplying power to an IC chip mounted on a board because of a large voltage drop.

In addition, forming the signal wiring layer on the surface of the multilayer ceramic substrate using thin film technology allows for finer wiring than when forming it using thick film printing technology, and it is easier to form wiring with the same density. This is because the number of signal wiring layers can be reduced, but tungsten and molybdenum used in the power supply wiring layer inside the multilayer ceramic substrate are more easily oxidized than metals such as gold, so inorganic 9JQ
It is not possible to perform firing in air during the formation of the film, and a process such as firing in a reducing atmosphere is required.

Further, since pattern printing of thin film wiring is generally performed using photolithography, the surface of the multilayer ceramic substrate is required to have extremely high smoothness in order to form fine wiring. However, multilayer ceramic substrates have through-hole wiring, and since a process of packing and printing conductive paste is added when forming these wirings, unevenness occurs on the board surface after sintering, especially in the through-hole wiring areas. There is. As a result, signal wiring formed on a multilayer 2-layer substrate via an inorganic insulating layer has to be a low-density wiring, and the characteristics of thin film technology, which allows for fine wiring, have not been fully utilized. .

[Summary of the invention].

The present invention has been made in view of the above problems, and its purpose is to provide a multilayer wiring board having a low-resistance power wiring layer and a high-density signal wiring layer, and a method for manufacturing the same. .

In order to achieve such an object, the multilayer wiring board of the present invention has an inorganic insulating layer formed on a glass ceramic substrate having a power supply wiring layer and through-hole wiring made of a conductor mainly composed of gold or silver palladium, and further comprising: A signal wiring layer is formed thereon using thin film technology. Furthermore, the method for manufacturing a multilayer wiring board of the present invention involves punching through holes in an unfired glass-ceramic green sheet, filling it with a conductive paste containing gold or silver palladium as a main component, and printing a power supply wiring layer with this conductive paste. A glass ceramic substrate is formed by firing, and then the surface is polished, and a dielectric thick film material and a conductive paste are suitably printed on this polished surface, and then fired again, and then signal wiring is formed on it by thin film technology. It forms a layer.

〔Example〕

Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 1 and FIG. 2 are diagrams showing one embodiment of the present invention.
FIG. 1 is a partially cutaway perspective view, and FIG. 2 is a sectional view.

In FIGS. 1 and 2, 1 is a multilayer glass ceramic substrate, and the first to third green sheets 1 to 10 are
3 are stacked and fired. Generally, glass ceramics can be sintered in air at a low temperature of 1400 DEG C. or lower, and the green sheets 101 to 103 are made of, for example, an inorganic composition according to the invention of Japanese Patent Application No. 55-88941.

104 and 105 are first and second green sheets 181
The first and second power supplies b' are printed on top of the 102 . 106 to 108 are the first through hole wiring 10) Wiring to the first to third spaces K-yh- formed in 101 to 103 A), the first through hole wiring 10
6 electrically connects the terminal 109 and the first power supply wiring layer 104, and the second through hole interconnection 107 connects the first power supply wiring layer 1.
04 and the second power distribution layer 1o5 are electrically connected, and the third
The through-hole wiring 108 electrically connects the second power supply wiring layer 105 and a signal wiring line θ to be described later. Note that since FIG. 1 shows a state in which the signal wiring layer has not yet been applied, one end of the third through-hole wiring 108 is an exposed portion 111 of the through-hole wiring surface on the surface 110 of the substrate 1. .

Reference numeral 2 denotes a signal wiring layer using inorganic thick film insulation, for interconnecting a plurality of IC chips mounted on the surface thereof, and terminals provided on the back surface of the multilayer ceramic substrate 1 and the IC chips. [19] is formed on the surface 110 of the multilayer ceramic substrate 1. This wiring layer 2
To explain the structure in more detail, a first inorganic insulating layer 201 is formed on the narrow surface 110 of the multilayer ceramic substrate 1, and a first signal wiring layer 202 is formed on it using thin film technology.
It is formed. The first signal wiring layer 202 and the through-hole wiring surface exposed portion 111 are the first signal wiring layer 202 and the through-hole wiring surface exposed portion 111.
It is electrically connected to 03 at an appropriate location.

A second inorganic insulating layer 2 is further provided on the first signal wiring layer.
04, and a second signal wiring layer 205 is formed thereon by thin film technology. First signal wiring layer 201
and the seventh signal wiring layer 205 are electrically connected to each other at an appropriate location by a second Guiahole wiring 206.

Next, a manufacturing process of a glass ceramic substrate in such a multilayer wiring board will be explained.

First, glass-ceramic unfired green sea)
Prepare holes 101 to 103, and make through holes 106 to 103 in each.
Punch holes for 108. Next, a thick film conductor paste mainly composed of gold or silver palladium is filled into the punched through holes of each sheet by printing. Furthermore, a first power wiring layer 104 is printed on the front surface of the first green sheet 101, and pads for forming terminals 109 are printed on the back surface. A second power wiring layer 105 is printed on the surface of the second green sheet 1020.

Next, the green sheets 101 to 103 are aligned and stacked, and each layer is pressed together using a press.

After that, this green sheet laminate was heated at 700°C to 90°C.
Calculate in air at 0°C. This allows the first to third
The green sheets 101 to 103 are integrated to form the multilayer ceramic substrate 1. At this time, each conductor paste is fired to form the power supply wiring layer 104, 105, through-hole wiring 106 to 108, the terminal 109, and the power supply. Wiring layer 1
04, 105 and through-hole wiring surface exposed portion 111
Electrical continuity connections are made between the two as necessary.

The exposed surface portion 111 of the third through-hole arrangement 108 is formed on the surface of the ceramic substrate 10 obtained in this way, but the through-hole wiring is filled with conductive paste and printed after being baked as described above. The surface is very uneven because it is in a bare state. Therefore, the surface 110 of the ceramic substrate 1 is polished after firing.

Next, the multilayer ceramic substrate 1 formed in this way
The manufacturing process of the wiring layer 2 using an inorganic thick film insulation formed on the surface of the substrate will be explained.

First, a temperature of 700°C was applied on the surface 110 of the multilayer ceramic substrate 1.
A dielectric material, such as an alumina glass insulating paste, which can be fired in air at ~900° C., is screen printed, and a conductive paste is further printed at the locations where the Guiahole wiring 203 is to be formed. Thereafter, by firing at 700° C. to 900° C., the first inorganic insulating layer 201 including the guiahole wiring 203 is formed. Then, this inorganic insulating layer 2
A first signal wiring layer 202 is formed on the first signal wiring layer 202 by thin film technology.

Specifically, the second signal wiring layer 205 is formed by sputtering titanium or palladium as a base metal film, and then forming the gold wiring by photolithography using a plating technique. signal wiring layer 2
It is formed by the same process as that used to form 02. That is, an alumina glass-based insulating paste and a conductive paste are printed and then fired to form an M2 inorganic insulating layer 204 including a guiahole wiring 206, and a second signal wiring J205 is formed on the inorganic insulating layer 204 using thin film technology. Form.

Note that although both the power supply wiring layer and the signal wiring layer in this example are multilayered, each may be a single layer.
Further, the number of layers may be determined as necessary.

〔Effect of the invention〕

As explained above, according to the multilayer wiring board and the manufacturing method thereof of the present invention, the glass ceramic board is used as the multilayer ceramic board forming the power supply wiring layer.
It is possible to sinter in air at a temperature of 0.degree. That is, it is possible to provide an excellent substrate with a small voltage drop in the power supply wiring.

Furthermore, the use of metals that are difficult to oxidize, mainly consisting of gold and silver-palladium, for the power wiring layer means that the inorganic insulating layer can be fired in the air during the process of forming the signal wiring layer. In addition, the surface of the ceramic substrate containing the power wiring layer is polished after firing in a reducing atmosphere. Allows fine wiring.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view showing one embodiment of the present invention, and FIG.
The figure is a sectional view. 1...Multilayer glass ceramic substrate, 10411...
・First power supply wiring layer, 105...Second power supply wiring layer, 106-108...First to third through-hole wiring L 109 Fist Φ...Terminal, 2...Inorganic Signal wiring layer using thick film insulation, 201. 204...First and second inorganic insulating layers, 202. 205...Φ first and second signal wiring layer, 203°2
06...First and second Guiahole wiring.

Claims (2)

[Claims] (1) A glass ceramic having one or more through-hole wirings and a power supply wiring layer made of one or more scraps of a conductor whose main component is gold or silver-palladium, with one end of the through-hole wiring exposed on the surface. a substrate; on the glass-ceramic substrate, one or more inorganic insulating layers formed by firing a dielectric thick film material; and one or more inorganic insulating layers formed by thin film technology on the inorganic insulating layers and electrically connected to the through-hole wiring. 1. A multilayer wiring board comprising: a signal wiring layer connected to a signal wiring layer; (2) Through holes were formed in an unfired glass-ceramic green sheet and a conductive paste containing gold or silver palladium as a main component was printed on the green sheet, and a stain source wiring layer was printed on the conductive paste on the green sheet. a first step of post-firing to form a glass-ceramic substrate; a second step of polishing the surface of the glass-ceramic substrate; and a step of applying an 8-electrode thick film material to areas other than the through-hole portions of the surface of the glass-ceramic substrate. A third step of printing and baking the conductive paste in the through hole portion to form an inorganic insulating layer including guiahole wiring, and forming a signal wiring layer by thin film technology on the inorganic insulating layer. A method for manufacturing a multilayer wiring board, characterized in that it comprises a fourth step of: