JPS6235547A - Cooling mechanism of semiconductor element - Google Patents

Abstract

PURPOSE:To obtain a cooling mechanism which need not fill good thermal conductive substance with ready working by so imparting a shape memory to a stud that, when temperature becomes a transition temperature or higher, it is deformed so that the upper portion is extended radially to closely contact with the sidewall of a cylinder. CONSTITUTION:A stud 1 of cylindrical shape is formed with an axial hole 18a from the upper surface, a plurality of slits 18b which arrive at the bottom of the hole 18a radially from the upper surface and female threads formed toward bottom axial direction, and made of a shape memory alloy of the material which becomes temperature exceeding transition temperature at high temperature raised by the heat of a semiconductor element 4. The heat transmitted from the element 4 becomes high temperature exceeding the transition temperature of the stud 1 to deform by the shape memory, and the upper portion is opened with the slits 18 to extend radially in contact with the sidewall of a cylinder 2. Here is transmitted from the stud 1 through a cylinder housing 7 to a cooling plate 8, and removed by coolant 11 which flows in the plate 8.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cooling mechanism for semiconductor devices characterized by a heat conduction mechanism between semiconductor devices and a cooling plate mounted on those devices.

[Prior Art] A method conventionally used for LSI packages in which a plurality of semiconductor elements are mounted on a substrate as a means of cooling highly integrated semiconductor elements is shown in Fig. 4. This cooling structure uses a liquid as a refrigerant, and an enlarged sectional view thereof is shown in FIG.

A piston 13 is pressed against the semiconductor element 4 mounted on the substrate 6 by a spring 14, and the heat generated in the semiconductor element 4 is transmitted to the cooling plate 8 through the piston 13, the gap 16, and the cylinder housing 7. is cooled by a refrigerant 11 injected from a refrigerant inlet 9 and discharged from a refrigerant outlet 10 . In addition, 2 is the cylinder,
15 is a material with good thermal conductivity, and 5 is a solder.

Further, as shown in FIG. 6, an enlarged longitudinal sectional view of one cylinder is shown in which a stud 17 and a metal fitting 3 are used for stud attachment instead of the piston 13 and spring 14.

In this structure, the semiconductor element 4 and the stud mounting metal fitting 3 are bonded with an insulating plate 12 in between, and the stud 1 is attached on the opposite side.
7 is fixed with a screw, and the semiconductor element 4 and the stud 17 are connected both thermally and mechanically. At this time, the heat generated in the semiconductor element 4 is removed by the coolant 11 on the cooling plate 8 through the insulating plate 12, the stud fitting 3, the stud 17, the gap 16, and the cylinder housing 7.

In all of the above examples, if air with poor heat conduction exists in the gap 16, the heat conduction efficiency will deteriorate, so the cylinder 2 of the cylinder housing 7, the piston 13, the stud 17
The machining accuracy of parts such as these has been increased to make the gap 16 minute.

Furthermore, the efficiency of heat conduction is increased by filling the gap with a material 15 having good thermal conductivity such as an inert gas or a compound.

[Problems to be solved] The above-mentioned conventional technology has the disadvantage that in order to improve heat conduction, the gap 16 between the piston 13 or stud 17 and the cylinder 2 must be made small, which requires high processing accuracy. .

Products filled with a good heat conductive substance such as an inert gas or compound15 to improve heat conduction require a special mechanism to prevent leakage, which complicates assembly and requires reuse when repairs are required. This causes processing problems.

Further, in the case of filling with a compound or the like, there is a problem that the metal parts of the semiconductor element 4 and the substrate 6 are corroded.

Those filled with a compound or the like, or those with a structure in which movable parts such as the piston 13 are pressed by a spring 14, have the disadvantage that the mounting direction is restricted because they are affected by gravity.

[Means for Solving Problems] The present invention has been made by focusing on the above-mentioned problems of the conventional technology.It is not necessary to reduce the gap between the stud and the cylinder, it is easy to process, and it is filled with a good heat conductive material. It is an object of the present invention to provide a cooling mechanism for semiconductor elements that is unnecessary, does not cause problems of corrosion, and is not limited in mounting direction.

To this end, the present invention provides an LSI package in which a plurality of semiconductor elements are mounted on a substrate, in which a stud is attached to the semiconductor element via an insulating plate and a stud mounting bracket, and a plurality of cylinders for receiving the stud are provided. In a cooling mechanism for a semiconductor device, in which a cylinder housing is mounted on the substrate and a cooling plate is provided in close contact with the cylinder housing, the stud is made of a material whose high temperature generated by heat generation of the semiconductor device exceeds the transformation temperature. Made of shape memory alloy, it has a cylindrical hole extending axially from the top surface, multiple slits extending radially from the top surface to the bottom of the hole, and a female thread axially provided on the bottom surface. When the temperature exceeds the transformation temperature, it deforms and the upper part expands radially, giving it a shape memory that makes it come into close contact with the side wall of the cylinder. The present invention provides a cooling mechanism for a semiconductor device characterized by having a diameter that is formed.

[Example] Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention. 2 is an enlarged longitudinal sectional view of the cylinder of FIG. 1 taken out at a low temperature below the transformation temperature during assembly, and FIG. 53 is an enlarged longitudinal sectional view at a high temperature above the transformation temperature.

The shape memory alloy stud 1 is cylindrical and has a hole 18a extending in the axial direction from the top surface, a plurality of slots 7) 18b extending radially from the top surface to the bottom of the hole 18a, and a female thread 19 in the axial direction of the bottom surface. ing.

Further, the stud 1 is made of a shape memory alloy that allows the high temperature generated by the heat generation of the semiconductor element 4 to exceed the transformation temperature, and when the temperature exceeds the transformation temperature, the stud 1 deforms and the upper part expands in the radial direction and the outer surface becomes It is given shape memory so that it comes into close contact with the side wall of the cylinder 2, and has a diameter with a defined gap between it and the side wall of the cylinder 2 at low temperatures below the transformation temperature. The cylinder 2 is provided in a cylinder housing 7, and has a shape memory alloy stud 1 therein, and has a diameter large enough to allow the inner wall to come into close contact when the shape memory alloy stud 1 is deformed at a high temperature above the transformation temperature. It's a hole. For stud mounting, the metal fitting 3 has a male thread 20 cut on the upper surface that engages with the female thread 19 of the shape memory alloy stud 1, and a flat surface on the lower surface. It is glued by sandwiching it. By screwing the shape memory alloy stud 1 into this, the semiconductor element 4 and the shape memory alloy stud 1 are mechanically and thermally connected and electrically insulated. Semiconductor element 4 is mounted on one side of substrate 6 with solder 5 .

Substrate 6 is attached to cylinder housing 7. This cylinder housing 7 is made of a material with very good thermal conductivity, such as copper or aluminum, and has a sufficient size to accommodate the cylinder 2.

A cooling plate 8 is attached to the cylinder housing 7, and its surfaces are finished in a shape that allows them to come into close contact with each other in order to improve heat conduction. A refrigerant 11 is injected into the cooling plate 8 from a refrigerant inlet 9 and discharged from a refrigerant outlet 10 in order to remove heat.

At low temperatures below the transformation temperature during assembly, the shape memory alloy stud 1 generates heat when electricity is applied to the semiconductor element 4 that closes the upper slit 18, as shown in FIG.
Heat is transmitted to the shape memory alloy stud 1 through the insulating plate 12 and the metal fitting 3 for stud attachment. The heat transferred from the semiconductor element 4 increases the temperature of the shape memory alloy stud 1, reaching a high temperature state exceeding the transformation temperature of the shape memory alloy.

At this time, the shape memory alloy stud 1 is deformed by shape memory, and the upper part opens the slit 18 and spreads in the radial direction and comes into close contact with the side wall of the cylinder 2. Heat is transferred from the shape memory alloy stud 1 through the cylinder housing 7 to the cooling plate 8, and is removed by the coolant 11 flowing inside the cooling plate 8. The shape memory alloy stud 1 at this time is in the state shown in FIG.

At this time, the upper part of the shape memory alloy stud 1 is in close contact with the side wall of the cylinder 2, and exhibits high thermal conductivity.

[Effects of the Invention] As explained above, the present invention provides an LSI package in which a stand is attached via an insulating plate and a stud mounting bracket to the semiconductor elements of an LSI package in which a plurality of semiconductor elements are mounted on a substrate. mounting a cylinder housing on the substrate with a plurality of cylinders for receiving studs;
In the semiconductor device cooling mechanism in which a cooling plate is provided in close contact with the cylinder housing, the stud is made of a shape memory alloy material in which the high temperature generated by heat generation of the semiconductor device exceeds the transformation temperature, and is cylindrical and has a top surface. It has a hole extending in the axial direction, multiple slits extending radially from the top surface to the bottom of the hole, and a female thread in the axial direction on the bottom surface.When the temperature exceeds the transformation temperature, the top part deforms. It is characterized by having a shape memory that spreads in the radial direction and comes into close contact with the side wall of the cylinder, is provided in the cylinder, and has a diameter that forms a defined gap between it and the side wall of the cylinder at room temperature. Since this is a cooling mechanism for semiconductor elements, shape memory alloy studs are used as a heat conduction mechanism. At high temperatures, the shape memory alloy studs deform and come into close contact with the side walls of the cylinder. There is no need to reduce the gap between the two. Because the metal is in close contact with the metal, there is no need to fill it with compounds or inert gases or other materials with good thermal conductivity, and there is no need for special mechanisms to prevent leakage or for a sturdy cylinder housing.

Furthermore, since there is no need for filling, there is no risk of corrosion of the metal parts of semiconductors or substrates, which improves maintainability and eliminates repair problems. Furthermore, since there are no members that are affected by gravity, there are no restrictions on the mounting direction.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, and FIG.
b) is PpJ1 at a low temperature below the transformation temperature during assembly.
An enlarged vertical cross-sectional view of one cylinder in the figure and its A-A cross-sectional view, and Figures 3 (A) and 3 (B) are vertical cross-sectional views at a high temperature above the transformation temperature that occurs when a semiconductor element generates heat, and its B- Figure 4 is a vertical cross-sectional view of the structure of the prior art; Figures 5 (a) and (b) are enlarged vertical cross-sectional views of one cylinder in Figure 4 and their C-C line cross-sectional views. , and FIGS. 6(a) and 6(b) are an enlarged vertical cross-sectional view of a structure using a stud instead of a piston and a cross-sectional view taken along the line D--D. 1: Shape memory alloy stud 2 Niji cylinder 3: Stud mounting metal fittings 4: Semiconductor element 6: Substrate 7: Cylinder housing 8: Cooling plate 12: Insulating plate 17: Studs 18a, 18b Nislit

Claims (1)

[Claims] A stud is attached to the semiconductor element of an LSI package in which a plurality of semiconductor elements are mounted on a substrate via an insulating plate and a stud mounting bracket, and a cylinder housing having a plurality of cylinders for receiving the stud is mounted on the substrate. In a cooling mechanism for a semiconductor device, the stud is made of a shape memory alloy of a material whose high temperature generated by heat generation of the semiconductor device exceeds a transformation temperature; It has a cylindrical shape with a hole extending in the axial direction from the top surface, multiple slits extending radially from the top surface to the bottom of the hole, and a female thread in the axial direction on the bottom surface, which deforms when the temperature exceeds the transformation temperature. The cylinder is provided with a shape memory such that its upper part expands in the radial direction and comes into close contact with the side wall of the cylinder, and is provided within the cylinder and has a diameter that forms a defined gap between it and the side wall of the cylinder at room temperature. A cooling mechanism for semiconductor devices characterized by: