JP2007048914A - Heat radiation structure of ic arranged on board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat radiation structure of ICs arranged on a board which can absorb a strain if a strain occurs on the board or bottom chassis. <P>SOLUTION: The back of a board 1 is attached to a bottom chassis 2, an IC 4 arranged on the back of the board 1 is held by the bottom chassis 2 via a heat sink sheet 6, a heat sink 7 is installed on the lower side of the heat sink sheet 6 arranged on a lower face of the IC 4, a plurality of long screws 8 are inserted into the bottom chassis 2 from its lower face to the heat sink 7, edges of the plurality of long screws 8 are butted against a lower face of the heat sink 7, a positioning recess 7b is formed on the lower face of the heat sink 7 so as to insert the edge of the long screw 8 thereinto, a spring washer 10 is arranged between a head 8a of the long screw 8 and the bottom chassis 2, and heat generating in the IC 4 is radiated by the heat sink sheet 6 and the heat sink 7. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a heat dissipation structure for an IC disposed on a substrate configured such that the back surface of the substrate is attached to the bottom chassis and the IC disposed on the back surface of the substrate is held by the bottom chassis via a heat dissipation sheet. Is.

  For example, as shown in FIG. 2, the conventional heat dissipation structure of the IC arranged on the substrate is such that the protrusions 102a on both sides of the bottom chassis 102 are brought into contact with the surface of the substrate 101, and the protrusions 102a are connected to 101 is attached and fixed. Further, a ball grit array 105 having an IC 104 is disposed on the back surface of the substrate 101, and a heat dissipation sheet 106 is disposed on the lower surface of the IC 104. A protrusion 102b at the center of the bottom chassis 102 is in contact with the lower surface of the heat dissipation sheet 106, and the IC 104 is held via the heat dissipation sheet 106 by the protrusion 102b.

  However, in this case, when the substrate 101 and the bottom chassis 102 are distorted, there is a problem that the distorted sheet must be absorbed only by the heat radiating sheet 106. In addition, there is a heat dissipating plate placed under the heat dissipating sheet, and this heat dissipating plate and the substrate are fixed with screws. However, since holes for inserting screws must be formed in the substrate, printed circuit boards There was a problem of taking up space on the surface.

  The first prior art is shown in FIGS. In this conventional substrate fixing structure, as shown in FIGS. 3A and 3B, a substrate 215 having a power transistor 220 is accommodated in a casing 211, and the substrate 215 is interposed via a plurality of heatsinks 216. Thus, the projections 214 are fixed to the side walls 213 of the casing 211. The power transistor 220 is fixed to the element mounting portion 219 of the heat sink 216. The direction of the set screw 223 for fixing the housing side mounting portion 218 of the heat sink 216 to the protrusion 214 is set to be perpendicular to the substrate 215 from the substrate 215 side. According to this, there is an advantage that stress on the substrate 215 due to a dimensional difference between the substrate side and the housing side in the planar direction of the substrate 215 can be reduced. (For example, refer to Patent Document 1).

However, in this case, there is a problem that no consideration is given to distortion in manufacturing the substrate 215 and the casing 211.
JP 2002-335089 A

  The present invention has been made in view of the above-described conventional problems, and provides an IC heat dissipation structure disposed on a substrate that can absorb the distortion even if the substrate or the bottom chassis is distorted. It is an object.

  The present invention has been proposed to solve the above problems, and the invention according to claim 1 is such that the back surface of the substrate is attached to the bottom chassis, and the IC disposed on the back surface of the substrate is a heat dissipation sheet. In the heat dissipation structure of the IC disposed on the substrate configured to be held by the bottom chassis via a heat sink, a heat dissipation plate is installed below the heat dissipation sheet disposed on the lower surface of the IC, and the bottom chassis A plurality of long screws are inserted from the lower surface toward the heat sink, and the tips of the long screws are in contact with the lower surface of the heat sink. A positioning recess into which the tip enters is formed, a spring washer is disposed between the head of the long screw and the bottom chassis, and the heat generated by the IC is radiated by the heat radiating sheet and the heat radiating plate. It is characterized in that it is.

  According to the second aspect of the present invention, the back surface of the substrate is attached to the bottom chassis, and the IC disposed on the back surface of the substrate is disposed on the substrate configured to be held by the bottom chassis via a heat dissipation sheet. In the heat dissipation structure of the IC, a heat dissipation plate is installed below the heat dissipation sheet disposed on the lower surface of the IC, and a plurality of long screws are inserted into the bottom chassis from the lower surface toward the heat dissipation plate. The ends of a plurality of long screws are in contact with the lower surface of the heat radiating plate, a spring washer is disposed between the head of the long screw and the bottom chassis, and heat generated by the IC is exchanged with the heat radiating sheet. The heat dissipation plate is configured to dissipate heat.

  According to the first aspect of the present invention, the heat radiating plate is installed below the heat radiating sheet disposed on the lower surface of the IC, and the tip of the long screw inserted from the bottom chassis toward the heat radiating plate is the lower surface of the heat radiating plate. Since the spring washer is disposed between the head of the long screw and the bottom chassis, even if the bottom chassis or the substrate is distorted, the distortion can be absorbed. In addition, since the positioning recess where the tip of the long screw enters the lower surface of the heat sink, the heat sink can be positioned, and if the long screw is misaligned, this deviation can be solved. it can.

  According to invention of Claim 2, a heat sink is installed under the heat dissipation sheet arrange | positioned at the lower surface of IC, and the front-end | tip of the long screw penetrated toward the heat sink from the bottom chassis is the lower surface of a heat sink Since the spring washer is disposed between the head of the long screw and the bottom chassis, even if the bottom chassis or the substrate is distorted, the distortion can be absorbed.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a heat dissipation structure for an IC arranged on a substrate according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a longitudinal sectional view showing an embodiment of a heat dissipation structure of an IC arranged on a substrate of the present invention.

  As shown in FIG. 1, in the heat dissipation structure of the IC disposed on the substrate of this embodiment, the back surface of the substrate 1 is attached and fixed to the protruding portions 2 a on both sides of the bottom chassis 2 with screws 3. In addition, a ball grit array 5 having an IC 4 is disposed at a substantially central portion of the back surface of the substrate 1, and a heat radiation sheet 6 is attached to the IC 4. A heat radiating plate 7 having a plurality of heat radiating legs 7 a is installed on the lower surface of the heat radiating sheet 6. It is contact | abutted in the state which entered into the recessed part 7b. A washer 9 and a spring washer 10 are disposed between the head 8 a of the long screw 8 and the bottom chassis 2. Further, the heat generated by the IC 4 is radiated by the heat radiating sheet 6 and the heat radiating plate 7. When the head 8a of the long screw 8 is large, only the spring washer 10 may be provided. Further, the present invention can be applied not only to the ball grid array 5 having the IC 4 but also to the IC alone. Furthermore, the number of the long screws 8 is not limited to four, but may be three or more.

  According to the present embodiment, the heat radiating plate 7 is installed on the lower side of the heat radiating sheet 6 disposed on the lower surface of the IC 4, and the tip of the long screw 8 inserted from the bottom chassis 2 toward the heat radiating plate 7 is the heat radiating plate 7. Since the spring washer 10 is disposed between the head 8a of the long screw 8 and the bottom chassis 2 even if the bottom chassis 2 and the substrate 1 are distorted, the distortion is generated. Can be absorbed. Moreover, since the positioning recess 7b into which the tip of the long screw 8 enters is formed on the lower surface of the heat radiating plate 7, the heat radiating plate 7 can be positioned. Can be solved.

It is a longitudinal cross-sectional view which shows embodiment of the thermal radiation structure of IC arrange | positioned at the board | substrate of this invention. It is a longitudinal cross-sectional view which shows the thermal radiation structure of IC arrange | positioned at the conventional board | substrate. The conventional fixing structure of a board | substrate is shown, (a) is the side view, (b) is the fragmentary top view.

Explanation of symbols

1 Substrate 2 Bottom chassis 2a Protruding part 3 Screw 4 IC
5 Ball grid array 6 Heat radiation sheet 7 Heat radiation plate 7a Heat radiation leg 7b Recess 8 Long screw 8a Head 9 Washer 10 Spring washer

Claims (2)

  In the heat dissipation structure of the IC disposed on the substrate, the back surface of the substrate is attached to the bottom chassis, and the IC disposed on the back surface of the substrate is held by the bottom chassis via the heat dissipation sheet. A heat radiating plate is installed on the lower side of the heat radiating sheet disposed on the lower surface, and a plurality of long screws are inserted into the bottom chassis from the lower surface toward the heat radiating plate. A positioning recess into which the tip of the long screw enters is formed on the lower surface of the heat sink, and a spring washer is provided between the head of the long screw and the bottom chassis. An IC heat dissipating structure disposed on a substrate, wherein the IC heat dissipates heat from the IC by the heat dissipating sheet and the heat dissipating plate.   In the heat dissipation structure of the IC disposed on the substrate, the back surface of the substrate is attached to the bottom chassis, and the IC disposed on the back surface of the substrate is held by the bottom chassis via the heat dissipation sheet. A heat radiating plate is installed on the lower side of the heat radiating sheet disposed on the lower surface, and a plurality of long screws are inserted into the bottom chassis from the lower surface toward the heat radiating plate. It is in contact with the lower surface of the heat radiating plate, and a spring washer is disposed between the head of the long screw and the bottom chassis, and the heat generated by the IC is radiated by the heat radiating sheet and the heat radiating plate. An IC heat dissipating structure disposed on a substrate, characterized in that: