JPH0395958A - Ceramic package with heat sink - Google Patents

Abstract

PURPOSE:To improve cooling effect and enhance reliability by enabling a heat sink which is adhered to a cap which blocks a chip and is adhered onto a ceramic substrate in a structure that a large fin and a small fin are mounted on a post at the center alternately. CONSTITUTION:A chip 2 is mounted onto an alumina ceramic substrate 1 which is formed in plane shape using an adhesion agent and a plurality of pins 5 are provided at the periphery part of lower surface of the ceramic substrate 1. A connection pad 3 is provided at the periphery part of the central hole, is connected to the pins 5 through the surface or inner surface of the ceramic substrate 1 electrically, and is connected to the terminal part of the chip 2 by a wiring member 4 such as a wire. With the upper surface of the ceramic substrate 1, the internal airtightness is maintained by adhering a gap 6 with an adhesive such as a low melting-point glass so that the chip 2 is covered. An aluminum heat sink 7 which is adhered onto the upper surface of the cap is in a structure where a large and small disc-shaped fins are aligned alternately at the central cylinder.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a ceramic package with a heat sink mounted with a chip such as an IC chip or an LSI chip. [Conventional technology] As can be understood from theoretical elements in advanced semiconductor device technology, the speed and power product per gate are gradually decreasing, and with the development of microfabrication technology, the area occupied by each gate is also gradually decreasing. are doing. For this reason, semiconductor chips tend to become faster and more highly integrated. On the other hand, packages that protect semiconductor chips and improve their reliability are being developed into the field of packaging, taking into consideration semiconductor chip bonding technology. Along with this, in recent years computer equipment, etc., have gradually been using various types of ceramic cases for mounting LSI semiconductor elements and high-density and miniaturized LSI chips in order to improve the processing performance and reliability of the equipment. It has become possible to incorporate it. By the way, as the degree of integration of elements increases, the power consumption of semiconductor chips also increases.
Therefore, LSI chips with large power consumption are mounted in cases made of materials such as ceramics, which have higher thermal conductivity than plastic. However, heat dissipation using only the ceramic board naturally has a limit to cooling the LSI chip. Therefore, in the conventional ceramic package mounted with the aforementioned high-speed and highly integrated LSI chip,
From the perspective of cooling the heat dissipated from the SI chip, a heat sink made of aluminum or copper, which has high heat dissipation efficiency, is integrally fixed to the top surface of the ceramic package using solder or adhesive with excellent thermal conductivity to dissipate heat. That's what I do.

Figure 3 is a perspective view of an example of a conventional ceramic package with a heat sink. In Fig. 3, 1 is a ceramic substrate, 5 is a bottle, 6 is a cap, and 7 is a heat sink. Figure 4 is a cross-sectional view of an example of a conventional ceramic package with a heat sink. In Fig. 4, 1 is a ceramic substrate, on which a chip 2 is mounted using a chip fixing agent. The chip 2 has connection pads 3 and wiring members 4 on a ceramic substrate l.
It is connected by. A plurality of bottles 5 are attached to the lower side of the ceramic substrate 1. A cap 6 is bonded to the top surface of the ceramic substrate so as to cover the chip 2 to keep the inside airtight. A heat sink 7 is adhered to the upper surface of the cap 6 using a heat sink adhesive. The heat sink 7 has a structure in which there is a cylinder in the center and several disk-shaped fins are attached to the cylinder. Ceramic packages with heat sinks with this type of structure are currently being manufactured. [Problems to be Solved by the Invention] However, the ceramic package with a heat sink having the above-described structure has the disadvantage that the heat sink does not have very good heat dissipation efficiency, and a sufficient cooling effect cannot be obtained. This causes problems such as a decrease in the operating speed of the device due to an increase in the temperature of the chip itself.

An object of the present invention is to provide a highly reliable ceramic package with a heat sink that has a sufficient heat dissipation effect even when a highly integrated LSI chip that generates a large amount of heat is mounted.

[Means to solve the problem]

The ceramic package with a heat sink of the present invention includes a ceramic substrate, a chip bonded to the ceramic substrate, a cap bonded to the ceramic substrate to cover the chip, and a large fin bonded to the cap. The structure includes a heat sink consisting of small fins and small fins attached alternately to the central column. [Function] As the degree of integration of elements increases, as in VLSIs, the power consumption of semiconductor chips increases. Therefore, LSI chips with high power consumption are packaged in materials such as ceramics, which have higher thermal conductivity than plastic. Must be installed. Furthermore, from the perspective of cooling the heat dissipated from the LSI chip, a heat sink made of aluminum or copper material with high heat dissipation efficiency is placed on the surface opposite to the fixed surface of the LSI chip using solder or adhesive with excellent thermal conductivity. This allows them to be fixed together and to dissipate heat. Although there are various shapes of heat sinks, one with a structure of several disc-shaped fins connected by supports is used because of the lack of dependence on wind direction during forced air cooling and the high heat dissipation efficiency of the heat sink alone. It will be done.

In the ceramic package with a heat sink of the present invention, the heat sink has a structure in which several large disc-shaped fins and small disc-shaped fins are alternately attached to a central pillar, so the small fins are attached. The surface area increases accordingly, and since it is small, the heat dissipation efficiency increases without reducing the flow velocity in the fin gaps.

This structure makes it possible to put into practical use a ceramic package with a heat sink that has high heat dissipation and high reliability as described above. [Example] Next, an example of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of an embodiment of the present invention.

In FIG. 1, 1 is a ceramic substrate, 5 is a pin, 6 is a cap, and 7 is a heat sink.

FIG. 2 is a sectional view of one embodiment of the present invention.

In FIG. 2, reference numeral 1 denotes an alumina ceramic substrate shaped like a flat plate, on which a chip 2 is mounted using a chip fixing agent. Reference numeral 5 designates a plurality of pins for connection to the board of the chip 2, and these pins 5 are erected at the periphery of the lower surface of the ceramic substrate 1. A connection pad 3 for connecting the pin 5 and the chip 2 is provided around the hole in the center of the ceramic substrate 1, and the connection pad 3 and the via 5 are electrically connected through the surface or inner layer of the ceramic substrate 1. It is connected to the. The terminal portion of the chip 2 is connected to a connection pad 3 connected to a vial 5 by a wiring member 4 such as a wire. The top surface of the ceramic substrate 1 is
A cap 6 is bonded to cover the chip 2 with an adhesive such as low-melting point glass to maintain airtightness inside. An aluminum heat sink 7 is bonded to the top surface of the cap 6 with a heat sink adhesive. The heat sink 7 has a cylinder in the center, and has a structure in which large disc-shaped fins and small disc-shaped fins are alternately arranged on the cylinder.

The thermal resistance of a heat sink with a structure in which large and small disc-shaped fins are arranged alternately in accordance with this example and a conventional heat sink in which only large disc-shaped fins are arranged in an arrangement was experimentally compared. In this example, when the wind speed is 5 m/s, the thermal resistance is 2. O
It was K/W. In contrast, traditional packaging
The thermal resistance was 2.2 K/W when the wind speed was 5 m/s. From the above, it was found that a package equipped with a heat sink consisting of alternating large and small fins has a lower thermal resistance than a package equipped with a heat sink consisting only of large fins. In the above embodiments, aluminum is used as the heat sink material, but it is clear that any material with good thermal conductivity can sufficiently achieve the effects of the present invention. [Effects of the Invention] As explained above, according to the present invention, it is possible to suppress the temperature rise of the chip and the ceramic package due to heat generation when energized, so a high-speed operation and highly reliable ceramic package can be obtained. There is an effect.

[Brief explanation of drawings]

1 and 2 are a perspective view and a sectional view of an embodiment of the present invention, and FIGS. 3 and 4 are a perspective view and a sectional view of an example of a conventional ceramic package with a heat sink. DESCRIPTION OF SYMBOLS 1... Ceramic board, 2... Chip, 3... Connection pad, 4... Wiring member, 5... Pin, 6...
Cap, 7... heat sink. Figure 1

Claims (1)

[Claims] A ceramic substrate, a chip bonded to the ceramic substrate, a cap bonded to the ceramic substrate to cover the chip, and large fins and small fins bonded to the cap alternately arranged in the center. A ceramic package with a heat sink, characterized in that the package includes a heat sink attached to a pillar.