JPS62216254A - Jig for heat transfer and heat dissipation method using said jig - Google Patents

Abstract

PURPOSE:To form and hold a small-sized heat-dissipating path positively by forming the heat-dissipating path in an air gap section in a radiator and a heating element by a tabular contacting member and pushing the contacting member against the wall surface of the air gap by a pressing member. CONSTITUTION:A connecting member 1 consisting of a tabular small piece having high thermal conductivity is used as a heat transfer jig inserted into an air gap section between a heating element 4 and a radiator plate 3 and shaping a heat transfer path, pressing members 2 having compressive elasticity are fixed to the connecting member 1, and the tabular small piece 1 is connected to the heating element 4 and the radiator plate 3 by the compressive elastic action of the pressing members 2. The cross section of the tabular connecting member 1 takes approximately an S-shape, and the connecting member 1 is constituted of flat upper contact section 11 and lower contact section 12 an an oblique section 13 tying these contact sections 11 and 12. One connecting section can be stuck fast to the heating element 4 and the other connecting section to an external heat-dissipating means respectively by the compressive elastic force of the pressing members 2. Accordingly, a contact area with the heating element is increased, the jig is miniaturized, and the deviation of a distance between the heating element and the radiator plate can be absorbed by its own deformation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to heat dissipation technology for semiconductor devices.More specifically, the present invention relates to heat dissipation technology for semiconductor devices.More specifically, the present invention relates to heat dissipation technology for semiconductor devices. A heat transfer jig that absorbs deviations in dimensions even when uneven distribution occurs due to deformation or non-uniformity in the thickness of individual semiconductor element fixing agents, and efficiently transfers heat to the heat sink. and a heat dissipation method using the same.

[Conventional technology]

Conventionally, methods used for this type of application include: ■ Filling with heat dissipation grease; ■ Sandwiching an elastic sheet for heat dissipation; and ■ Pressing a piston-shaped heat dissipation piece with a spring so that a large area of heat dissipation surface faces the side of the piston. There are ways to do this. Each is shown below.

In the method (2) using heat dissipation grease, a gel-like silicone resin mixed with fine powder of boron nitride, silicon carbide, etc., which has high thermal conductivity, is filled into the space where heat is to be transferred. In this method, the distance between the surfaces that conduct heat transfer is several 1
It is used when the spacing is less than 0.00 microns, but if the spacing is expected to be larger than that, grease will leak out and it cannot be used. The heat transfer coefficient is also not large, about /W/m:C, and there is a drawback that it cannot be applied to fill a large space.

■The method using an elastic sheet for heat dissipation is several to microns.
It is used to fill gaps of several millimeters, and there is no problem of leakage, but the heat transfer coefficient is only a few W/m:C, and it has the disadvantage that it is not very brittle.

The basic concept of the method of pressing the piston-shaped heat dissipating piece (2) is shown in Figure 3. As shown in the figure, in this case, heat from a heat generating element (4) such as a semiconductor element is transferred to a heat absorber 1 (or a heat radiator).
A piston (5) is used to transmit the signal to (2). The piston (5) receives heat from the heating element (4) through the spring (6). Heat is radiated from the piston (5) to the heat absorber (8) through the gas layer (7) on the side surface of the piston. Such a structure can absorb the dimensional deviation of the gap between the heat generating element (4) and the heat absorber (8). This effect will be explained with reference to FIG. In Figure 3, the same parts as in Figure 3 are given the same reference numerals, so these are omitted. r is a pipe through which the cooling medium flows, 10 is an element fixing agent such as solder, and 10 is a plurality of elements. (4) is mounted on this board. As shown in the figure, even if the thickness of each adhesive (9) of a plurality of elements is unevenly distributed, this deviation is absorbed and the piston-shaped heat dissipation piece is connected to all the elements to dissipate heat. A route can be reliably formed. In addition, in this structure, when the heating element is thermally strained, that is, when the heating element is displaced from 1 to 1 μB due to thermal expansion as shown in Fig. 1, the amount of acceptance can absorb the deviation between each heating element. , it is possible to reliably form a heat dissipation path even if there are multiple elements. Further, in the structure shown in FIG. 5, since the tip of the piston piece is given a curvature, a substantially constant contact area can be ensured even when the heating element is inclined as shown in FIG. This means that the contact area remains constant even when the piston piece (5) itself is tilted and comes into contact with the element because of the gap (7), as shown in Figure 2, as well as when the element is tilted due to poor installation conditions. This suggests that it can be maintained at However, the structure using such a piston piece has the following serious drawbacks. That is, first of all, it is difficult to miniaturize because it requires mechanical parts such as piston pieces and springs, and in particular, as shown in d in Fig. 6, the mechanism parts between the heating element and the cooling medium pipe are The drawback was that the distance could not be made smaller. In addition, in order to increase the heat transfer efficiency of the gas layer (7), a large area must be taken, and measures such as helium sealing are also required, which requires maintenance.

Reliability problems also arise. Furthermore, since the tip of the piston piece (5) has a curvature, only a limited portion of the total cross-sectional area of the piston piece (5) functions as a contact area, which has the disadvantage of low heat transfer efficiency. .

[Purpose of the invention]

The purpose of the present invention is to solve such drawbacks, and to provide a heat transfer device with a simple structure, which has a large contact area with the heating element, is compact, and can absorb deviations in the distance between the heating element and the heat sink through its own deformation. An object of the present invention is to provide a jig and a heat radiation method using the jig.

[Structure of the invention]

The present invention uses a small plate-like piece (connection member) with high thermal conductivity as a heat transfer jig that is inserted into the gap between the heating element and the heat sink to form a heat transfer path, and this is compressed with compressive elasticity. The method is characterized by the use of a jig in which the pressure member is fixed and the small plate-like piece is connected to the heating element and the heat sink by the compressive elastic action of the pressure member.

Furthermore, since the plate-shaped connecting member has an approximately S-shaped cross section, it consists of an upper contact part (fil) which is flat as T, a lower contact part (12), and an oblique part (L3 and L3) connecting these. Compressive elastic pressure members (2
) are connected, so even if the connecting member is made of a material that has high thermal conductivity but is difficult to elastically deform, the compressive elastic force of the pressure member will cause one of the connecting parts to become a heating element. It can be brought into close contact with the semiconductor element, and the other connecting portion can be brought into close contact with the external heat dissipation means. In this way, a heat dissipation path from NPI to P2 can be formed as shown in FIG.

Furthermore, when a plurality of connecting members are connected to the same compressive elastic pressure member in multiple sets of multiple stages, as shown in FIG. Since the space utilization efficiency of the connecting member is increased, heat transfer performance can be improved.

Furthermore, in the present invention, a heat transfer jig in which a connecting member and a pressure member are integrated is inserted into the gap between the semiconductor element and the external heat dissipation means, and the heat transfer jig itself is placed on both sides of the gap. Since it has a structure that can apply force, it also has the advantage of being able to stand on its own with only its constituent elements.

[Example 1] Fig. 1 is a diagram illustrating the basic concept of the heat transfer jig of the present invention, which is a contact member formed by bending a small plate-like piece with a high thermal conductivity into an approximately S-shape. , // is the upper contact part, 12
is the lower contact portion, and /3 is the hypotenuse portion. Further, 2 is a pressure member having compressive elasticity. Note that the pressure member is required to have compressive elasticity at least in the vertical direction in FIG. 1. That is, it is essential to utilize such compressive elastic properties to produce an action of pressing the upper contact sI upward and the lower contact portion U downward. As long as these conditions are satisfied, the material may be elastic in the transverse direction, or may be made of a material that is deformed so as to bend in the longitudinal direction.

In addition, in FIG. 1(b), the upper contact portion and the lower contact portion are given a slightly convex curvature. This is because in the structure shown in Figure 1 (,), for example, if the gap into which the jig is to be inserted is large and the jig is deformed greatly, the entire surface of the contact part cannot make contact, and only the ends make contact. There is a risk that a situation may occur. In that case, the thermal resistance of the heat radiation path increases. On the other hand, if the contact surface is given a curvature (6) as shown in FIG. 1(b), a substantially constant contact area can always be ensured even if the contact portion is inclined.

The mounting state will be described below using the structure shown in FIG. m1 (b).

FIG. 2 shows an embodiment in which the heat transfer jig of the present invention is mounted in a cavity.

In the figure, / is a contact member with high thermal conductivity, λ is a pressure member that has compressive elasticity in the vertical direction at least in the drawing, a three-wire heat absorber (or heat radiator), and ≠ is a heating element such as a semiconductor. . Further, an arrow pointing from Pl to P indicates a heat radiation path. In these figures, both ends of the plate-shaped piece (1) are in close contact with the heat generating element (4) and the heat radiating element (8) by the pressure member (2), so that heat transfer can be achieved.

Even if there is a deviation in the gap size between the heating element (4) and the heat radiating element (8), the contact between the plate-like pieces is ensured by the expansion and contraction of the pressure member. Furthermore, as mentioned earlier, due to this expansion and contraction, the surface of the heating element (4) or the heat radiating element (8) and the plate-shaped small piece (1
) Even if the angle formed with the plate-shaped piece (1) changes, the close contact over a wide range is maintained due to the six curvatures given to both ends of the plate-shaped piece (1).

The thermal resistance of the present invention includes a thermal resistance hole 1 in a small plate-like piece for heat transfer (1), and a thermal resistance hole between the small plate-like piece and a heating element (4).

It can be expressed as the sum of the thermal resistance islands between the small plate-shaped piece and the heat sink (8).

R, can be expressed as G! Heat transfer coefficient of heat transfer material [W/m・”C] W: Width of heat transfer material (m) Thickness of TI heat transfer material piece [m] L: Length of heat transfer material piece [m] For example , for a copper piece with width C1 thickness 0.3M and length pwws, G=316, so R,,; 20.I''C/W.

几! , R8 is the thermal resistance of the space between the heat transfer material piece and the heating element or heat sink. Heat dissipation grease CG for this part only
= / W/m・°C), and the thickness of the space is 5 μm.
, assuming that the area is 7 m square, 几 = 几 =, t''c/W. Therefore, in the above example of dimensions, one plate-shaped piece for heat transfer B
oThermal resistance is R, + R, + R,, = 302"C/'
W Totoru. In the structure shown in Fig. 2, when using the upper dimensions, the gap distance between the heating element (4) and the heat radiating element (3) is /, 0 to 2
．． It changes arbitrarily within a range of about 0 fins. This distance is J-
The isometric heat transfer coefficient G of the air gap when ows is /
A [W/m・℃] has a heat dissipation capacity that is more than 10 times that of using only heat dissipation grease.

Furthermore, the distance between the air gaps is approximately 2+w, which makes it possible to realize a heat dissipation structure that is more than 10 times smaller than when using a piston structure and has a deviation absorbing ability.

Note that the material, cross-sectional shape, and dimensions of the pressure member (2) can be arbitrarily selected, and the contact pressure can be set in an extremely wide range.

[Example]

FIG. 3 shows a second embodiment of the heat transfer jig of the present invention. The names of each part are the same as in FIG. 1 and will be omitted.

The heat transfer material is divided into a plurality of plate-like pieces, and
Since each basic unit can be deformed independently, the contact surface (heat transfer surface) of the heating element or heat dissipating element may have irregularities or other deviations, so that the gap size may not be uniform over the entire contact surface. Even in such a case, each basic unit reliably forms a heat dissipation path, so there is an advantage that the overall effective contact area does not decrease.

Furthermore, in the structure of the present invention, since the heat transfer jig itself has a pressurizing function, by inserting the heat transfer jig of the present invention into the gap between the heating element and the heat radiating element, It also has the advantage of being self-supporting without requiring any other support.

[Example 3] A third embodiment of the heat transfer jig of the present invention is shown in the Mμ diagram.

Figure ≠ (,) is a perspective view, and Figure φ (b) is a sectional view.

The names of each part are the same as in FIG. 3, so their description will be omitted. In Fig. µ, contact members (1) and (1)' are arranged in an interdigitated manner, and compared to the structure shown in Fig. 3, a larger number of contact members are connected to all the contact surfaces, and the contact surface is Even if the surface is not flat, the effective contact area can be kept large.

Further, by adopting such a structure, even if a lateral displacement force occurs, there is an advantage that the heat dissipation path can be maintained more stably.

〔Effect of the invention〕

As explained above, the present invention forms a heat radiation path using a plate-shaped contact member made of a material with excellent thermal conductivity in the gap between the heat radiation body and the heating element where the heat transfer path is to be formed, and In order to ensure that the contact portion is in contact with both walls of the cavity, the contact member is pressed against the walls of the cavity using a pressure member with excellent disarmament elasticity.
Furthermore, the contact surface of the contact member is designed to have a slightly convex curvature, so it is small and
2″j has the advantage of reliably forming and maintaining a heat radiation path!
! Furthermore, since the contact member and the pressure member are combined as described above, there is an advantage that excellent materials can be independently selected according to the intended functions of each member.

That is, for the contact member, a light material with excellent thermal conductivity can be used even if the elastic force is not large, and for the pressure member, a material with high compressive elasticity may be used even though the thermal conductivity is low. I can do seven things. Furthermore, as shown in FIG. 3 and FIG. Even if the main surface of the heating element is uneven*6 and the main surfaces are not parallel to each other and are tilted, a heat radiation path can be reliably formed and maintained across the entire main surface. There are advantages.

Another advantage is that such excellent characteristics can be achieved at low cost with an extremely simple configuration.

[Brief explanation of drawings]

FIGS. 1(a) and 1(b) are perspective views showing the basic structure of the heat transfer jig of the present invention, respectively. FIG. 1 is a sectional view for explaining the mounting state and heat radiation path of the heat transfer jig of the present invention shown in FIG. 1(b). FIG. 3 is a perspective view of an embodiment in which a plurality of basic structures of the present invention are arranged. Figures (a) and (b) are a perspective view and a sectional view of an embodiment in which a plurality of basic structures of the present invention are arranged in an interdigital pattern. Figure 5 is a diagram illustrating the basic structure of a conventional heat transfer jig, Figure 6 is a sectional view illustrating multiple mounting states of the conventional heat transfer jig, and Figures 1 and 2 are conventional heat transfer jigs. It is a figure explaining the function of a jig. 1', /...Plate-shaped contact member with high thermal conductivity, K...Pressure member with compressive elasticity, 3...Heat absorber (
or heat sink), μ... heating element (or 1 heating element),
! ...Piston small piece, 6...Spring, 7...Gap, r...Pipeline through which the cooling medium flows, Ri...Fixing agent for heat generating element, IO...Mounting board for heat generating element .

Claims (5)

[Claims] (1) A plate-shaped first material with high thermal conductivity is bent into an almost S-shape, and an upper contact portion (11) and a lower contact portion (12) are formed.
A contact member (1) consisting of A heat transfer jig characterized in that the contact member (1) and the pressure member (2) each include a pressure member (2) made of a second material having the following properties. (2) The heat transfer jig according to claim 1, wherein the contact surfaces of the upper contact portion (11) and the lower contact portion (12) are slightly curved in a convex shape. (3) A heat transfer jig according to claim 1, characterized in that a plurality of contact members (1) are connected to one pressure member (2). (4) A plurality of pressure members (2) are aligned in the longitudinal direction and arranged at predetermined intervals, and a contact member (1) is connected and arranged between adjacent pressure members (2). A heat transfer jig according to claim 1, characterized in that: (5) In the heat dissipation method described above, in which a heat transfer jig made of a material with high thermal conductivity is interposed in the gap between the semiconductor element and the external heat dissipation means, and the heat generated by the semiconductor element is transferred to the external heat dissipation means. The heat transfer jig is formed by bending a plate-shaped first material with high thermal conductivity into a substantially S-shape to form a contact member consisting of an upper contact portion, a lower contact portion, and an oblique side portion, and A pressing member made of a second material having compressive elasticity is provided in connection with the lower part of the upper contact part and the upper part of the lower contact part, and the jig is composed of the contact member and the pressing member, and A heat dissipation method characterized in that a contact member is pressed onto a semiconductor element and an external heat dissipation means by compressive elastic force of a pressing member of a jig to form a heat dissipation path.