JPH02121355A - Ceramic multilayer substrate - Google Patents

Abstract

PURPOSE:To enable the forced cooling of an IC and the like through the intermediary of a substrate by a method wherein three or more sheet-like ceramics are laminated to form the substrate, at least one of intermediate layers is partially hollowed, and a coolant path provided with an inlet and an outlet as a whole is formed inside the substrate. CONSTITUTION:A hollowed section 2a is provided to a second layer 2 when it is still a green sheet before layers are laminated. The manufacturing method is such that a first, a second, and a third layer, 1-3, are cut off out of green sheets corresponding to the size of a substrate the same as a conventional multilayer substrate, the second layer 2 is hollowed to form the hollowed part 2a, and the layers are laminated and burned. Or, as the second layer 2 are substantially divided into two pieces, 2c and 2b, through the hollowed part 2a, the pieces, 2b and 2c, may be separately cut off from a green sheet and positionally aligned to be laminated. An appropriate cap or the like is fixed to an inlet and an outlet of coolant respectively, cooling water or the like is introduced into a coolant path 4 and circulated to cool the whole substrate, so that for instance the heat released from an IC or the like mounted on the first layer 1 can be effectively absorbed.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a substrate for mounting semiconductor devices such as ICs, and more particularly to a substrate in which sheet-shaped ceramics are laminated in multiple layers.

<Prior Art> In recent years, as semiconductor devices have become faster and more highly integrated, heat generation has become a problem. Particularly in PGAs (bin grid arrays), hybrid ICs, and the like, heat is intensively generated as the density of elements increases.

Conventionally, as techniques for dissipating such heat to the outside, techniques such as using a metal base substrate or attaching a heat sink to the PGA are known.

<Problems to be Solved by the Invention> Among conventional heat dissipation techniques, it is difficult to achieve high-density multilayer wiring with a metal base substrate, and it is difficult to miniaturize a PGA with a heat sink.

An object of the present invention is to provide a circuit board that is small in size, has a high heat dissipation (cooling) effect, and can be easily adapted to high-density multilayer wiring.

<Means for Solving the Problems> In order to achieve the above object, in the present invention, three or more layers of sheet-like ceramics are laminated to form a substrate, and among the intermediate layers excluding the top layer and bottom layer, At least one layer is partially pierced, and the hollow portion is communicated directly or through another layer to the outside of the substrate, thereby forming a coolant passageway with an inlet and an outlet within the substrate as a whole. ing.

A coolant passage is formed inside the board, so by guiding cooling water etc. into this passage, the IC mounted on the board can be cooled.
The heat generated from the substrate is forcibly removed by cooling water and the like through this substrate.

Since it is a laminated board, multilayer wiring is possible by avoiding refrigerant passages.

<Embodiment> FIG. 1 is an external view of an embodiment of the present invention, and FIG. 2 is an exploded perspective view thereof.

The substrate is 3 layers of sheet-like ceramics such as alumina 1.2
and 3 are laminated, and a refrigerant passage 4 extending in a U-shape along the surface of the substrate is formed therein. The refrigerant passage 4 communicates with a refrigerant port 5 and a refrigerant outlet 6 at the end surface of the substrate.

The refrigerant passage 4, the refrigerant population 5, and the outlet 6 are formed by providing a U-shaped punch-through portion 2a in the second layer 2 sandwiched between the uppermost first layer 1 and the lowermost third layer 3. .

That is, the hollow portion 2a is formed in the second layer 2 in the state of the green sheet before lamination of each layer.

The manufacturing method is, for example, like a normal multilayer board, the first to third layers 1 to 3 are cut out from a green sheet according to the size of the board, and the second layer 2 is punched out to form a hollow part 2a. After that, each layer is laminated and fired. Alternatively, the second layer 2 has substantially two leaves (
2a, 2b), each of these layers 2a2b may be individually cut out from the green sheet, aligned, and laminated.

In the above embodiment of the present invention, the refrigerant population 5 and the refrigerant outlet 6
By fixing a suitable cap or the like to the cooling water and circulating cooling water or the like into the coolant passage 4, the entire board is cooled, and heat from, for example, an IC mounted on the first layer 1 is effectively removed. Can be done.

FIG. 3 is an external view of another embodiment of the present invention, and FIG. 4 is an exploded perspective view thereof.

In this example, four layers of sheet-like ceramics 11 to 14 are laminated to form the substrate, and the refrigerant passage 15 is formed across both the second and third layers 12 and 13, which are intermediate layers, to form the substrate. It communicates with the refrigerant port 16 and the refrigerant outlet 17 on the end face.

That is, the second layer 12 has hollow portions 12a and 12b corresponding to the refrigerant inlets and outlets 16 and 17 on one end surface thereof, and hollow portions 9 extending parallel to the above-mentioned one end surface at a predetermined distance from the hollow portions 12a and 12b.
A piercing portion 12c is formed in the third layer 13.
Two hollow parts 1 extending parallel to each other at a pitch equal to the pitch between the hollow parts 12a and 12b of the second layer 12
3a and 13b are formed.

Then, the first and fourth layers 11.14 are stacked with the second and third layers 12.13 in between, and in this stacked state, each hollow portion is 12 a −+ 13 a −+ 12 c →1
3b → 12b and are configured to communicate with each other.

By forming the refrigerant passages 15 over multiple layers as described above, a sufficient cooling effect can be obtained even for a multilayer board of four or more layers. In addition, by appropriately distributing the 9j perforations between layers, the sheet will not be separated into two sheets by forming perforations as in the examples shown in Figures 1 and 2. This also has the effect of facilitating positioning during stacking.

In each of the above embodiments, by providing through holes before laminating each layer and printing conductors on the surface of each layer, it is possible to use it as a multilayer wiring board. However, it is necessary to avoid refrigerant passages at the through-hole forming position and conductor printing position.

Note that the present invention can also be applied to multilayer substrates with five or more layers,
Of course, the refrigerant passage can be formed over three or more intermediate layers.

In addition to the end surface of the substrate, the coolant inlet and outlet can also be formed on the front or back surface of the substrate by drilling through holes in the top or bottom layer.

<Effects of the Invention> As explained above, according to the present invention, since the coolant passage is formed inside the board, the ICs etc. mounted on the board are forcibly cooled through this board. Even if a large heat generating element such as a PAG or hybrid IC is installed, it can be sufficiently cooled.

Furthermore, since there is no need to provide a heat sink or the like outside the board, it is compact and can easily handle high-density multilayer wiring.

Furthermore, it can be manufactured in the same process as conventional ceramic multilayer substrates by simply punching out appropriate parts before laminating them, which has the effect that the cost does not increase significantly.

[Brief explanation of drawings]

Fig. 1 is an external view of an embodiment of the present invention, Fig. 2 is an exploded perspective view thereof, Fig. 3 is an external view of another embodiment of the invention, and Fig. 4 is an exploded perspective view thereof. 1.2.3... Sheet-like ceramics 2a... Puncture part

Claims (1)

[Claims] In a substrate formed by laminating three or more layers of sheet-like ceramics, at least one layer is partially hollowed out among the intermediate layers excluding the top layer and the bottom layer, and this hollow portion directly or through the other layers. 1. A ceramic multilayer substrate, characterized in that a refrigerant passage is formed in the substrate, communicating with the outside of the substrate at at least two places via the substrate, and having an inlet and an outlet as a whole.