JP5024314B2 - Semiconductor device heat dissipation structure and electronic device including the same - Google Patents

Description

  The present invention relates to a heat dissipation structure for a semiconductor element and an electronic device including the same, and more particularly to a heat dissipation structure for a semiconductor element that handles a high-frequency signal.

  Conventionally, for example, electronic devices such as a BUC (Block Up Converter) and a high-frequency power amplifier used for satellite communication VSAT (Ultra-Small Earth Station) as a microwave transmitter are MMIC (Monolithic Microwave Integrated Circuit), Semiconductor elements such as an MIC (microwave integrated circuit) and a high frequency amplifier are mounted. Among these semiconductor elements, those that generate a large amount of heat are directly fixed to the metal casing or heat sink of the electronic device so that they are not destroyed by the generated heat. Heat is transferred to the housing or heat sink, and heat is radiated from the metal housing or heat sink to the outside.

  In order to improve the heat dissipation efficiency with the above structure, a structure in which a heat dissipation sheet (heat transfer member) is sandwiched between the heat sink and the semiconductor element and the both are fixed has been proposed. This structure is disposed between a mounting seat and a fixing portion, for example, a semiconductor element having a flange-shaped mounting seat on the lower side, a heat sink having a fixing portion for fixing the mounting seat of the semiconductor element. The fixing portion includes a concave surface into which the mounting seat is fitted and a shallow concave portion formed on the bottom surface of the concave surface, and the thermal radiation sheet is laid on the concave portion. Thus, after the heat dissipation sheet is temporarily placed in the recess of the heat sink, the mounting seat of the semiconductor element is screwed to the concave surface of the heat sink from above the heat dissipation sheet (see, for example, Patent Document 1).

  However, in patent document 1, since it was the structure dented in two steps which has a recessed part in the bottom face of the concave surface of a heat sink, there existed a fault that the process for arrange | positioning a thermal radiation sheet was not easy. In particular, an electronic device for satellite communication has a housing made of aluminum die-casting, and has a drawback that it is difficult to process in two steps in terms of processing accuracy and cost.

  Therefore, in Patent Document 1, in order to simplify the processing for disposing the heat dissipation sheet, for example, if the heat dissipation sheet is laid on the bottom surface of the concave surface without forming the concave portion on the bottom surface of the concave surface of the heat sink. Although there is no means for regulating the position of the heat dissipation sheet when the semiconductor element is screwed, there is a high possibility that the heat dissipation sheet will be misaligned. In addition, there is a method of applying heat-dissipating grease in place of the heat-dissipating sheet in the bottom of the concave surface. However, in high-frequency semiconductor elements used for electronic devices for satellite communications, etc. The high frequency characteristics may be deteriorated.

Japanese Patent Laying-Open No. 2005-183582 (pages 5-6, FIG. 2)

  In view of the above problems, the present invention has a simple structure in which a heat conduction member is sandwiched between a metal housing or heat sink of an electronic device and a semiconductor element and the heat dissipation of the semiconductor element is promoted. An object of the present invention is to provide a heat dissipation structure for a semiconductor element and an electronic device including the same, in which a good heat dissipation performance can be obtained.

  In order to solve the above-mentioned problems, the present invention provides a semiconductor device having a flange-shaped mounting seat on a lower side, a housing having a fixing portion for fixing the mounting seat, and the mounting In a heat dissipation structure of a semiconductor element comprising a heat transfer member disposed between a seat and the fixed portion, the fixed portion is in a direction intersecting the first concave surface into which the mounting seat is fitted and the first concave surface. The heat transfer member is disposed on the second concave surface. The heat transfer member is formed on the second concave surface.

  According to a second aspect of the present invention, in the heat dissipation structure for a semiconductor device according to the first aspect, the depth of the second concave surface is equal to the depth of the first concave surface.

  According to a third aspect of the present invention, in the heat dissipation structure for a semiconductor element according to the first or second aspect, the heat transfer member is made of a soft metal foil having an uneven cross section.

  According to a fourth aspect of the present invention, in the heat dissipation structure for a semiconductor element according to any one of the first to third aspects, the heat transfer member is formed in a cross shape and extends from the second concave surface to the first concave surface. It is the structure characterized by being arranged.

  According to a fifth aspect of the present invention, in the heat dissipation structure for a semiconductor element according to the fourth aspect, there are screwing portions for fixing the semiconductor element to the housing at positions corresponding to the mounting seat and the first concave surface, respectively. The cross-shaped heat transfer member is provided so as to have a shape that escapes the screwing portion.

  A sixth aspect of the present invention is an electronic device including the semiconductor element heat dissipation structure according to any one of the first to fifth aspects.

  According to the present invention, it is possible to realize a heat dissipation structure for a semiconductor element and an electronic apparatus including the same, which have a simple structure, can be easily assembled, and can obtain good heat dissipation performance.

It is an external view which shows the semiconductor element used for the thermal radiation structure of the semiconductor element by this invention, (A) is a top view, (B) is a front view, (C) is a side view. It is a disassembled perspective view which shows the electronic device provided with the heat dissipation structure of the semiconductor element by this invention. 2A and 2B are cross-sectional views illustrating an electronic device having a heat dissipation structure for a semiconductor device according to the present invention, in which FIG. 2A is a cross-sectional view taken along the line AA ′ in FIG. 2 and FIG. It is sectional drawing. It is a perspective view which shows other embodiment of the heat-transfer member used for the thermal radiation structure of the semiconductor element by this invention.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. As shown in FIGS. 1 and 2, as a microwave transmitter for handling high-frequency signals in the Ku-band or K-band according to the present invention, a BUC (Block) used for satellite communication VSAT (miniature earth station) or the like is used. Electronic devices such as up converters and high frequency power amplifiers have semiconductor elements 200 such as MMICs (monolithic microwave integrated circuits), MICs (microwave integrated circuits), and high frequency amplifiers mounted inside the metal casing 100. Yes. The semiconductor element 200 has a semiconductor chip with heat generation (not shown) mounted therein, and the semiconductor chip is hermetically sealed with a package 210 formed of a material having good thermal conductivity.

  In particular, in the semiconductor element 200 with a large calorific value such as a power amplifier MMIC, a flange-like mounting seat 220 protrudes on both sides of the lower portion of the package 210, and a mounting screw 230 is inserted into the mounting seat 220. Notched holes 221 are formed respectively. Further, thin plate-like pin terminals 211 serving as terminals for VGG, RFin, VDD, and RFout are projected on both sides of the package 210 in a direction different from the projecting direction of the mounting seat 220, respectively. It is connected to the.

  Next, as shown in FIG. 2, the circuit board 300 disposed on the inner surface 110 of the metal casing 100 of the electronic device is formed with a circuit conductor pattern 310 made of a microstrip line constituting a high-frequency planar circuit on the upper surface. An opening 320 for inserting the semiconductor element 200 having the pin terminal 211 connected to the circuit conductor pattern 310 by soldering is formed. The circuit conductor pattern 310 is formed up to the periphery of the opening 320, and the opening 320 is formed in a size corresponding to the mounting seat 220 of the semiconductor element 200.

  The heat transfer member 400 is made of a rectangular soft metal foil having electrical conductivity and thermal conductivity, and has, for example, an embossed cross-sectional uneven shape. As shown in FIG. 2, the length a in the short direction of the heat transfer member 400 is a length corresponding to the length b in the longitudinal direction of the package 210 as shown in FIG. Yes. The heat transfer member 400 only needs to have at least conductivity and heat conductivity, and is a soft metal foil or other resin sheet (including a conductive resin sheet) that has not been processed into a concavo-convex shape in cross section. May be.

  The metal casing 100 of the electronic device is made of a metal such as copper or aluminum having thermal conductivity. For example, the heat radiating fins 120 are integrally formed on the outer surface of an aluminum die-cast casing. The inner surface 110 of the metal casing 100 facing the heat dissipating fin 120 is provided with a fixing portion 130 for fixing the mounting seat 220 of the semiconductor element 200. The fixing portion 130 is a first portion into which the mounting seat 220 of the semiconductor element 200 is fitted. It consists of a first concave surface 140 and a second concave surface 150 formed in a direction perpendicular to the first concave surface 140. The heat transfer member 400 is disposed on the second concave surface 150 so as to face the package 210 of the semiconductor element 200.

  A screw hole 141 into which the mounting screw 230 is screwed is formed on the bottom surface of the first concave surface 140, and the second concave surface 150 is formed smoothly and continuously so that the depth of the second concave surface 150 is equal to the depth of the first concave surface 140. Has been. Furthermore, the depths of the first concave surface 140 and the second concave surface 150 are set such that the circuit conductor pattern 310 and the semiconductor element 200 formed on the circuit board 300 in a state where the circuit board 300 is disposed on the inner surface 110 of the metal casing 100. It is determined in consideration of the thickness of the heat transfer member 40 sandwiched between the second concave surface 150 and the semiconductor element 200 so that the pin terminals 211 are flush with each other.

  Thereby, the process for forming the 2nd concave surface 150 is easy, and the position of the heat transfer member 400 can be controlled only by arrange | positioning the heat transfer member 400 in the 2nd concave surface 150. FIG. Specifically, in the assembly process, after the heat transfer member 400 is disposed on the second concave surface 150, before the mounting seat 220 of the semiconductor element 200 is screwed to the second concave surface 150, the metal is formed on the assembly work table. The heat transfer member 400 moves by touching the housing 100, or immediately after the heat transfer member 400 is disposed, the heat transfer member 400 moves by touching an arrangement means such as tweezers. The heat transfer member 400 does not move at the time of screwing, and displacement of the heat transfer member 400 can be prevented.

  As shown in FIG. 3A, the semiconductor element 200 is made up of a metal housing by a notch hole 221 formed in the mounting seat 220 of the semiconductor element 200 and a screw hole 141 formed in the bottom surface of the first concave surface 140. A screwing portion 240 for fixing to the body 100 is configured.

  In the assembly procedure of the electronic device having the heat dissipation structure of the semiconductor element 200 described above, the heat transfer member 400 is first disposed on the second concave surface 150 of the metal casing 100. Next, the circuit board 300 is disposed on the inner surface 110 of the metal housing 100, and the ground conductor (not shown) formed on the lower surface of the circuit board 300 is brought into contact with the inner surface 110 of the metal housing 100. Thereafter, the semiconductor element 200 is inserted from the opening 320 of the circuit board 300, the mounting seat 220 of the semiconductor element 200 is fitted on the first concave surface 140 of the metal housing 100, and the mounting screw 230 is inserted into the notch hole of the mounting seat 220. 221 is inserted and screwed into a screw hole 141 formed in the bottom surface of the first concave surface 140.

  Then, the mounting screw 230 is fastened and fixed in a state where the semiconductor element 200 is positioned so that the circuit conductor pattern 310 of the circuit board 300 and the pin terminal 211 of the semiconductor element 200 are in an appropriate position. Finally, the pin terminal 211 of the semiconductor element 200 is soldered and connected to the circuit conductor pattern 310 of the circuit board 300.

  As shown in FIG. 3A and FIG. 3B, the electronic device assembled in this manner has the second concave surface of the mounting seat 220 of the semiconductor element 200 by the optimum screw tightening torque by the mounting screw 230. The heat transfer member 400 laid in 150 is pressed, and the heat transfer member 400 is sandwiched between the mounting seat 220 of the semiconductor element 200 and the bottom surface of the second concave surface 150 and is in contact with each other. Yes. Thereby, the heat generated in the package 210 of the semiconductor element 200 is transferred from the mounting seat 220 of the semiconductor element 200 to the heat transfer member 400, and is transferred to the metal casing 100 via the heat transfer member 400. The heat is radiated from the metal casing 100 to the outside.

  According to the heat dissipation structure of the semiconductor element 200 described above, a simple structure, easy assembly, and good heat dissipation performance can be obtained, temperature rise of the semiconductor element 200 is suppressed, and destruction of the semiconductor element 200 is prevented. Can do. Further, since the heat transfer member 400 is sandwiched directly under the semiconductor chip (not shown) inside the package 210 of the semiconductor element 200, even a member having a small heat transfer member 400 can effectively dissipate heat.

  In addition, although the mounting seat 220 of the semiconductor element 200 and the bottom surface of the second concave surface 150 are actually slightly uneven and warped, the heat transfer member 400 having an uneven cross-section has the mounting seat 220 and the second concave surface 150. The portion with good flatness is completely crushed, and the portion with bad flatness is deformed and brought into contact with each other, so that the contact state between the mounting seat 220 and the second concave surface 150 is excellent and stable electrical Conductivity can be obtained. In addition to the mounting screw 230, the heat transfer member 400 provides sufficient conduction between the mounting seat 220 and the metal housing 100, and the ground potential between the semiconductor element 200 and the metal housing 100 is stabilized. The high frequency characteristics of the electronic device can be improved. Furthermore, since not only conduction between the mounting seat 220 and the metal casing 100 but also adhesion is enhanced, heat conduction is increased and heat dissipation can be improved.

  Next, other embodiments of the heat transfer member 400 will be described. As shown in FIG. 4, the heat transfer member 500 is formed in a cross shape instead of a rectangle like the heat transfer member 400, and is arranged to extend from the second concave surface 150 to the first concave surface 140. ing. The heat transfer member 500 has a shape that escapes from the screw hole 141 formed in the bottom surface of the first concave surface 140 and the notch hole 221 formed in the mounting seat 220 of the semiconductor element 200, that is, The length c of the heat transfer member 500 is smaller than the length d between the two screw holes 141 shown in FIG. 2, and the heat transfer member 500 is disposed inside the two screw holes 141. The heat transfer member 500 is replaced with the heat transfer member 400 and laid on both surfaces of the first concave surface 140 and the second concave surface 150, and the mounting seat 220 of the semiconductor element 200 and the first concave surface 140 and the second concave surface 150 It is sandwiched between them so that they touch each other.

  As a result, the heat transfer member 500 can be arranged so as to extend in the direction of the first concave surface 140 in addition to the direction of the second concave surface 150, so that compared to the case where the heat transfer member 400 is used, the mounting seat 220. The area in contact with each other between the metal casing 100 and the metal casing 100 is widened, and heat dissipation from the metal casing 100 to the outside can be improved. Further, since the heat transfer member 500 is disposed so as to escape from the screw hole 141 and the notch hole 221, it is possible to prevent the heat transfer member 500 from getting in the way when the mounting seat 220 of the semiconductor element 200 is screwed.

  In the present embodiment, the first concave surface 140 and the second concave surface 150 are formed to be orthogonal to the inner surface 110 of the metal casing 100. However, the present invention is not limited to this, and the first The concave surface 140 and the second concave surface 150 may be formed so as to intersect with each other. In this case, the heat transfer member 500 may be formed in a cross shape corresponding to the intersecting angle.

  According to the semiconductor element heat dissipation structure of the present invention described above, the semiconductor element 200 including the flange-shaped mounting seat 220 on the lower side, and the metal housing 100 including the fixing portion 130 for fixing the mounting seat 220 to the semiconductor element 200. In the structure comprising the heat transfer member 400 disposed between the mounting seat 220 and the fixing portion 130, the fixing portion 130 intersects the first concave surface 140 into which the mounting seat 220 is fitted and the first concave surface 140. The heat transfer member 400 is arranged on the second concave surface 150. As a result, a simple structure, easy assembly, and good heat dissipation performance can be obtained.

  In addition, the depth of the second concave surface 150 is made equal to the depth of the first concave surface 140. Thereby, the process for forming the 2nd concave surface 150 is easy, and the position shift of the heat-transfer member 400 arrange | positioned at the 2nd concave surface 150 can be prevented.

  Further, the heat transfer member 400 was made of a soft metal foil having an uneven cross section. As a result, when the semiconductor element 200 is screwed to the metal casing 100, the soft metal foil is completely crushed in the flat part of the mounting seat 220 and the second concave surface 150, and deformed in the bad part, Since they can be brought into contact with each other, conduction between the mounting seat 220 and the second concave surface 150 can be improved. And since not only the conduction | electrical_connection between the mounting seat 220 and the 2nd concave surface 150 but adhesiveness becomes strong, heat conduction becomes large and can improve heat dissipation.

  In addition, the heat transfer member 500 is formed in a cross shape and is disposed from the second concave surface 150 to the first concave surface 140. As a result, the heat transfer member 500 extends in the direction of the first concave surface 140, and the area of contact between the mounting seat 220 and the metal casing 100 increases, so that heat dissipation from the metal casing 100 to the outside is improved. Can be improved.

  Furthermore, a screwing portion 240 for fixing the semiconductor element 200 to the metal casing 100 is provided at a position corresponding to each of the mounting seat 220 and the first concave surface 140, and the cross-shaped heat transfer member 500 has the screwing portion 240. The escaped shape was used. Thereby, when screwing the mounting seat 220 of the semiconductor element 200, it can be prevented from getting in the way.

DESCRIPTION OF SYMBOLS 100 Metal housing | casing 110 Inner surface 120 Radiation fin 130 Fixed part 140 1st concave surface 141 Screw hole 150 2nd concave surface 200 Semiconductor element 210 Package 211 Pin terminal 220 Mounting seat 221 Notch hole 230 Mounting screw 240 Screw fixing part 300 Circuit board 310 Circuit Conductor pattern 320 Opening 400 Heat transfer member 500 Heat transfer member

Claims (6)

  From a semiconductor element having a flange-shaped mounting seat on the lower side, a housing having a fixing portion for fixing the mounting seat, and a heat transfer member disposed between the mounting seat and the fixing portion In the semiconductor device heat dissipation structure, the fixing portion includes a first concave surface into which the mounting seat is fitted, and a second concave surface formed in a direction intersecting the first concave surface, and the heat transfer member is the second concave surface. A heat dissipation structure for a semiconductor element, wherein the heat dissipation structure is disposed on a concave surface.   2. The heat dissipation structure for a semiconductor device according to claim 1, wherein a depth of the second concave surface is equal to a depth of the first concave surface.   3. The heat dissipation structure for a semiconductor element according to claim 1, wherein the heat transfer member is made of a soft metal foil having an uneven cross section.   4. The heat dissipation structure for a semiconductor device according to claim 1, wherein the heat transfer member is formed in a cross shape and is disposed from the second concave surface to the first concave surface. 5. .   A screwing portion for fixing the semiconductor element to the housing is provided at a position corresponding to each of the mounting seat and the first concave surface, and the cross-shaped heat transfer member has a shape in which the screwing portion escapes. 5. The heat dissipation structure for a semiconductor device according to claim 4, wherein:   An electronic device comprising the semiconductor element heat dissipation structure according to claim 1.