JP5246133B2 - Semiconductor module - Google Patents

Description

  The present invention relates to a semiconductor module including a plurality of semiconductor devices.

  2. Description of the Related Art In recent years, along with higher performance and higher functionality of electronic devices, semiconductor devices such as semiconductor chips and semiconductor packages mounted on electronic devices are required to process a large amount of data at high speed. Therefore, the operating frequency and operating current of the semiconductor device are increasing, and the amount of heat generated by the semiconductor device is increasing. In order to operate the semiconductor device stably, it is necessary to maintain the temperature of the semiconductor device below a predetermined temperature. Therefore, it is indispensable to provide a heat dissipation / cooling means for radiating the heat generated by the semiconductor device.

  In addition, semiconductor modules such as a multi-chip module (MCM) and a system-in-package (SiP) including a plurality of semiconductor chips and semiconductor packages have been used. In such a semiconductor device, typically, a plurality of semiconductor devices are mounted face-down on a common wiring board (also referred to as a circuit board or the like), and a common heat dissipation structure is disposed on the plurality of semiconductor devices. . That is, the back surface side of the semiconductor device is a main heat radiating surface, and a single heat radiating plate or a heat sink disposed on the heat radiating surfaces of the plurality of semiconductor devices dissipates heat from these semiconductor elements.

  FIG. 1 illustrates a typical semiconductor module 10 according to the prior art including a plurality of semiconductor devices. FIG. 1A is a top view of the semiconductor module 10, and a dotted line 30 in the drawing indicates the position of the semiconductor device to be mounted. FIG. 1B is a cross-sectional view of the semiconductor module 10 seen through from the straight line A-A ′ side of FIG. FIG. 1A shows only a part of the semiconductor module 10, but the semiconductor module 10 has, for example, a symmetric structure with respect to the straight line A-A '.

  The semiconductor module 10 includes a wiring board 20, a plurality of semiconductor devices 30, and a heat sink 40. The semiconductor module 10 further includes a reinforcing plate 60 and a screw 61 with a spring that fixes the heat sink 40 to the wiring board 20 and / or the reinforcing plate 60. In this example, each semiconductor device 30 is a semiconductor package. The semiconductor package 30 includes a semiconductor chip 31, a package substrate 32, a plurality of pads 33 formed on the surface opposite to the chip mounting surface of the package substrate 32, a plurality of solder balls 34 formed on the pads 33, and a heat spreader 35. Have Each semiconductor device 30 is mounted face-down on the wiring board 20 by reflow of the solder balls 34 on the pads 21 on the surface of the wiring board 20. The heat sink 40 is in contact with the heat radiating surfaces 36 of the plurality of semiconductor devices 30 through thermal grease or the like as necessary, and can dissipate the heat generated by these semiconductor devices 30.

  However, in a semiconductor module on which a plurality of semiconductor devices having different functions are mounted, the thickness of each semiconductor chip, the package standard (including the thickness) of each semiconductor package, and the like can be different. In addition, even when the thickness of each semiconductor device is the same, mounting of each semiconductor device may occur due to manufacturing errors when mounted on the wiring board, warping of the wiring board, and / or the fixing condition of the spring-loaded screw. Variations in height and tilt can occur.

  FIG. 2 shows an example in which non-uniformity occurs in the mounting height despite the same package standard. Referring to FIG. 2A, in one of the two semiconductor devices 30, the parallelism with respect to the wiring board 20 is impaired, and a gap 70 is generated between the heat radiating surface 36 and the heat sink 40. . This can occur, for example, due to manufacturing errors in the reflow process. Referring to FIG. 2B, the wiring board 20 itself is warped, and a gap 70 is generated between the heat radiation surface 36 and the heat sink 40 of each of the two semiconductor devices 30. For example, this may be caused by a thermal cycle during a reflow process or during use due to a mismatch in thermal expansion coefficient between the circuit board 20 and the semiconductor device 30. In this specification, the fact that the heat radiation surface of the semiconductor device is inclined with respect to the heat radiator so as to generate a gap between the semiconductor device and the heat sink is referred to as “mounting inclination”.

  The gap 70 between the semiconductor device 30 and the heat sink 40 due to the mounting inclination hinders heat dissipation from the semiconductor device 30 or a part of the semiconductor device 30 and reduces the stability and reliability of the operation of the semiconductor device 30.

  In a semiconductor module that cools a plurality of semiconductor devices having different thicknesses or the like with a single radiator, as a technique for avoiding the generation of the gap as described above, flexibility or fluidity is provided between each semiconductor device and the radiator. There are known techniques for interposing a relatively thick layer of thermally conductive material having As such an intervening layer, a grease-like or sheet-like thermal compound is usually used, and the generation of a gap can be suppressed and the stress can be relieved at the joint portion between the semiconductor device and the radiator. In order to improve thermal conductivity, a method using solder for the intervening layer has also been proposed. When using an intervening layer made of solder, due to its fluidity at the time of melting, it absorbs variations in the thickness of the semiconductor device when mounting the radiator, and each semiconductor device and the radiator have a relatively high thermal conductivity without any gaps. Can be joined.

Japanese Patent Laid-Open No. 7-32257 JP-A-11-26659 JP 2002-261206 A

  However, in the method of interposing a heat conductive material layer between each semiconductor device and the heat radiating body, if a heat conductive material having a thickness sufficient to avoid the occurrence of the gap as described above is inserted, the semiconductor device and The thermal resistance increases with the radiator, and the cooling capacity of the semiconductor device is greatly reduced.

  This problem can be alleviated by using solder instead of a thermal compound for the thermally conductive material. However, in reality, a separate heat conductor is interposed between the semiconductor device and the solder in order to prevent the solder from wrapping around the surface side of the semiconductor device such as a semiconductor chip when the radiator is mounted. There is a need. Therefore, the number of parts of the semiconductor module increases, and the effect of improving the cooling capacity due to the use of solder is limited. Moreover, since the solder is solidified when the semiconductor module is used, the effect of relieving the stress between the semiconductor device and the heat radiating member caused by the thermal cycle during use is compared with the method using the thermal compound. It will be low. Furthermore, in order to remove the heat sink after soldering, it is necessary to perform another heat treatment, which makes it difficult to upgrade / repair the semiconductor device or other components in the semiconductor module. There is also the problem of doing.

  Therefore, without increasing the number of parts, it is possible to avoid the generation of a gap between each of the plurality of semiconductor devices and the radiator, and to efficiently cool the plurality of semiconductor devices with one radiator. A semiconductor module mounting structure is desired.

  According to one aspect, a semiconductor module is provided that includes a wiring board, a plurality of semiconductor devices arranged on the wiring board, and a heat radiating body arranged on the plurality of semiconductor devices. The radiator includes a main body common to the plurality of semiconductor devices and a plurality of protrusions protruding from the main body toward the plurality of semiconductor devices so as to be in thermal contact with the plurality of semiconductor devices. The main body and the plurality of protrusions are integrally formed. Each protrusion has a slit cut from the side surface of the protrusion. The slit is formed so that the bottom surface of the protrusion can be displaced following the corresponding top surface of the plurality of semiconductor devices.

  The integrally formed radiator itself absorbs the thickness difference between the plurality of semiconductor devices and the mounting inclination of each semiconductor device. This ensures good contact between the radiator and each of the plurality of semiconductor devices without using separate components, and efficiently dissipates heat generated by the plurality of semiconductor devices with one radiator. Can be made.

It is a figure which illustrates the semiconductor module which concerns on the prior art containing a several semiconductor device. It is a figure which illustrates the problem which may arise in the semiconductor module of FIG. It is a figure which illustrates the semiconductor module concerning one embodiment containing a plurality of semiconductor devices. It is a figure which illustrates the displacement absorption operation | movement in the semiconductor module of FIG. FIG. 6 is a diagram illustrating another displacement absorbing operation in the semiconductor module of FIG. 3. It is a figure which shows an example of a displacement absorption mechanism. It is a figure which shows another example of a displacement absorption mechanism. It is a figure which shows the 1st modification of a semiconductor module. It is a figure which shows the 2nd modification of a semiconductor module. It is a figure which shows the 3rd modification of a semiconductor module. It is a figure which shows the 4th modification of a semiconductor module. It is a figure which shows an example of the manufacturing method of a displacement absorption mechanism.

  Hereinafter, embodiments will be described in detail with reference to the drawings. In the drawings, various components are not necessarily drawn to the same scale. Throughout the drawings, the same or corresponding components are denoted by the same or similar reference numerals.

  First, a semiconductor module 100 according to an embodiment including a plurality of semiconductor devices will be described with reference to FIG. FIG. 3A is a top view of the semiconductor module 100, and a dotted line 130 in the drawing indicates the position of the semiconductor device to be mounted. FIG. 3B shows a cross-sectional view of the semiconductor module 100 seen through from the straight line A-A ′ side of FIG. Although FIG. 3A shows only a part of the semiconductor module 100, the semiconductor module 100 has, for example, a symmetric structure with respect to the straight line A-A ′.

  The semiconductor module 100 includes a wiring board 120, a plurality of semiconductor devices 130, and a heat radiator 140. The semiconductor module 100 further includes a reinforcing plate 160 and fixing means 161 for fixing the heat radiating body 140 as necessary. The wiring substrate 120 is not particularly limited, but is, for example, an epoxy resin substrate, and may include a plurality of resin insulating layers and wiring layers as necessary. The wiring board 120 may be a motherboard of an electronic device on which the semiconductor device 130 and the heat radiator 140 are mounted. The reinforcing plate 160 is, for example, a metal plate or an alloy plate, and is disposed on the side opposite to the semiconductor device mounting surface of the wiring substrate 120. The fixing means 161 may be a screw with a spring as shown in the figure, for example, but may be other means that can fix the heat radiator 140 and the wiring board 120 and / or the reinforcing plate 160, such as a screw without a spring structure. Good.

  Each semiconductor device 130 may be a semiconductor bare chip or a semiconductor package having an array of connection terminals on the surface, such as a ball grid array (BGA) type or a land grid array (LGA) type. In the illustrated example, each semiconductor device 130 is a semiconductor package. The semiconductor package 130 includes a semiconductor chip 131, a package substrate 132, a plurality of pads 133 formed on the surface opposite to the chip mounting surface of the package substrate 132, a plurality of connection terminals 134 formed on the pads 133, and a heat spreader. 135. The package substrate 132 is, for example, a resin substrate or a ceramic substrate, and the plurality of connection terminals 134 are, for example, an array of conductive connectors such as a solder ball array or metal pins. Each semiconductor device 130 is mounted face-down on the wiring board 120 by, for example, reflow of the solder balls 134 on the pads 121 on the surface of the wiring board 120.

  The semiconductor chip 131 in the semiconductor package 130 is preferably a BGA type or LGA type semiconductor chip, and is flip-chip mounted on the package substrate 132. Then, heat generated in the semiconductor chip 131 is conducted to the heat radiation surface 136 of the semiconductor package 130, that is, the upper surface of the heat spreader 135 by the heat spreader 135 disposed on the upper surface (back surface) of the semiconductor chip 131. The heat spreader 135 has a high thermal conductivity material, preferably copper (Cu), Cu alloy, aluminum (Al), Al alloy, or carbon composite (carbon fiber / resin composite). The heat spreader 135 is preferably brought into contact with the semiconductor chip 131 via a grease-like or sheet-like thermal compound so as to absorb the difference in thermal expansion coefficient between the semiconductor chip 131 such as silicon (Si) and the heat spreader 135. The thermal compound may be formed by mixing metal oxide particles such as alumina filler or metal fine particles having good thermal conductivity into silicone oil.

  The radiator 140 can be, for example, a heat sink or a heat sink having Cu, Cu alloy, Al, or Al alloy. In the illustrated example, the heat radiating body 140 is a heat sink having a plurality of heat radiating fins 142 on the top surface of the main body 141 which is preferably planar. The heat sink 140 is in thermal contact with the heat radiation surfaces 136 of the plurality of semiconductor devices 130 and can dissipate the heat generated by the semiconductor devices 130. For example, when the semiconductor device 130 is a semiconductor bare chip, the heat sink 140 is brought into contact with the semiconductor device 130 via a grease-like or sheet-like thermal compound. Thereby, the difference in thermal expansion coefficient between the semiconductor device 130 and the heat sink 140 can be absorbed. The thermal compound may contain, for example, metal oxide particles such as alumina filler, metal fine particles, and the like.

  The heat sink 140 further includes a plurality of protrusions protruding from the main body 141 toward the semiconductor device 130 so as to correspond to the respective heat sink surfaces (bottom surfaces) of the plurality of semiconductor devices 130 in contact with the heat receiving surfaces (bottom surfaces). Part 150. The protrusion 150 is integrally formed with the main body 141. In the following description, the projection 150 is also referred to as a displacement absorbing mechanism 150 in view of the functions described later. The displacement absorbing mechanism 150 constitutes an elastic structure that deforms following the height and mounting inclination of the heat radiation surface 136 of the semiconductor device 130.

  For example, the displacement absorbing mechanism 150 includes one or more slits 151 cut from the side surfaces of the protrusions. The slit 151 includes two or more plate-like plate portions 152 separated in the vertical direction and a connection portion 153 that connects the plate portions 152 adjacent in the vertical direction. The connecting portion 153 serves as a fulcrum for displacement of the plate portion 152 as will be described later, and is hereinafter also referred to as a hinge portion. Each slit 151 has a closed end 151a adjacent to the hinge portion 153 and an open end 151b. As shown in the figure, the closed end 151a has a hollow portion such as a column having a diameter larger than the slit height. May be. Such a hollow portion can enhance the fulcrum function of the hinge portion 153.

  In the illustrated example, the heat sink 140 has a two-stage displacement absorbing mechanism 150 having two slits 151-1, 2, hinge portions 153-1, 2, and three plate portions 152-1, 2, 3. doing. The slit 151-1 may be formed at the boundary between the main body 141 and the protrusion 150 of the heat sink 140 so that the uppermost plate portion 152-1 does not exist. As one design example, each plate part may have a thickness of 1 mm-2 mm, each slit part may have a height of 50 μm-400 μm, and the displacement absorbing mechanism 150 may have a height of approximately 3 mm-7 mm. . Further, the lowermost plate portion 152-3 that is in contact with the semiconductor device 130 has a heat capacity sufficient to receive the heat generated by the semiconductor device 130 than the upper plate portions 152-1 and 152-2. It may be formed thick. Each plate portion 152 has a planar shape, for example, substantially the same size and shape as the heat radiation surface 136 of the corresponding semiconductor device 130, and each side is preferably 1 mm, for example, so as to allow a mounting error in the planar direction. It is designed to be larger than the corresponding side of the semiconductor device 130 by the size. Alternatively, each plate portion 152 may be designed to be significantly larger than the size of the heat dissipation surface 136 of the semiconductor device 130 so as to have a sufficient heat capacity according to the allowable temperature of the semiconductor package.

  The displacement absorbing mechanism 150 absorbs the difference in thickness and mounting inclination of the semiconductor device 130, and a gap is generated on the contact surface between the heat radiating surface 136 of the semiconductor device 130 and the heat sink 140 (lowermost plate portion 152-3). This can be prevented. Therefore, a heat conduction path is formed between the plurality of semiconductor devices 130 and the heat sink 140 that is not affected by the difference in thickness of the semiconductor device 130 or the mounting inclination.

  Here, FIGS. 4 and 5 illustrate the effect of the displacement absorbing mechanism 150 of the heat sink 140. For example, as shown in FIG. 4A, the heat sink 140 may be inclined with respect to the wiring board 120 and thus the heat radiation surface 136 of the semiconductor device 130 due to non-uniform fixation of the fixing means 161. Even in such a case, the displacement absorbing mechanism 150 can absorb the inclination by displacing the plate portion 152 so as to deform the slit 151 with the hinge portion 153 as a fulcrum. Further, as shown in FIG. 4B, the displacement absorbing mechanism 150 is the same even when the wiring board 120 is warped and the heat radiation surface 136 of each of the semiconductor devices 130 is inclined. The mounting inclination can be absorbed. Further, as shown in FIG. 5, some of the standards of the plurality of semiconductor devices 130 are different, and for example, the pitch and height of the solder balls 134 and the thickness of the semiconductor package 130 may be different. Even in such a case, the displacement absorbing mechanism 150 can absorb the difference in thickness by contracting one more than the other. Therefore, in various situations, the operation of the displacement absorbing mechanism 150 prevents a gap from being generated between the heat radiation surface 136 of each semiconductor device 130 and the heat sink 140. In addition, the shape of the slit 151 after the deformation shown in the drawing is not necessarily depicted accurately.

  As described above, by integrally forming the displacement absorbing mechanism 150 that elastically deforms following the thickness and mounting inclination of each semiconductor device 130 as the heat radiating body 140, the heat generated in the semiconductor device 130 can be efficiently dissipated. Is possible. Therefore, good thermal contact between the heat sink and each semiconductor device is ensured without using a separate element such as an intentionally thickened heat conducting material layer and generated in a plurality of semiconductor devices. Heat can be efficiently dissipated by a single radiator.

  Further, since the displacement absorbing mechanism 150 equalizes the load applied to the plurality of semiconductor devices 130 even during the operation of the semiconductor module 100, it suppresses the generation of excessive loads and stresses on some semiconductor devices due to thermal cycles. In addition, the stability and reliability of the operation of the semiconductor module can be improved. In addition, since the heat sink 140 is in pressure contact with the semiconductor device 130, the heat sink 140 can be removed later to easily upgrade / repair the semiconductor device 130 and / or other components, thereby improving the maintainability of the semiconductor module. Can be improved.

  Next, the displacement absorbing mechanism 150 shown in FIG. 3 will be described in more detail with reference to FIG. 6A is a bottom view of the heat sink 140, and FIGS. 6B and 6C are cross-sectional views taken along lines B-B ′ and C-C ′ in FIG.

  In this example, the quadrangular prism-shaped protrusion 150 has slits 151-1 and 151-2 cut from two opposite side surfaces among the four side surfaces. In this two-stage displacement absorbing mechanism 150, the two hinge portions 153-1 and 153-2 are positioned on two opposing sides of each semiconductor device with which the displacement absorbing mechanism 150 is in contact, and are parallel to each other (straight line C- (Direction parallel to C ′). Therefore, the displacement absorbing mechanism 150 indicates the mounting inclination of the semiconductor device that rotates around one axial direction (direction perpendicular to the paper surface of FIG. 6B) by an arrow in FIG. 6B. In addition, it can be absorbed by the displacement of the plate portions 152-2 and 3 with the hinge portions 153-1 and 2 as fulcrums. The displacement absorbing mechanism 150 is also capable of absorbing the difference in thickness between the plurality of semiconductor devices by contracting upward while keeping the lowermost plate portion 152-3 horizontal.

  Note that the displacement absorbing mechanism 150 in FIG. 6 is movable within a mounting inclination that rotates around an axial direction perpendicular to the one axial direction (a direction perpendicular to the paper surface in FIG. 6C). Can be absorbed by the elastic deformation of the hinges 153-1 and 153-2.

  The displacement absorbing mechanism 150 can be variously modified to realize a more complicated or larger displacement absorbing operation. An example is shown in FIG. FIGS. 7A to 7C are views similar to FIGS. 6A to 6C, respectively. In the modified example of FIG. 7, the two hinge portions 153′-1 and 153′-1, 2 of the two-stage displacement absorbing mechanism 150 ′ are positioned on two adjacent sides of each semiconductor device with which the displacement absorbing mechanism 150 ′ is in contact. And extend substantially perpendicular to each other. Therefore, the displacement absorbing mechanism 150 ′ has a mounting inclination of the semiconductor device that rotates around two axial directions (directions perpendicular to the planes of FIG. 6B and FIG. 6C) as hinge portions 153 ′. It can be absorbed by the combined displacement of the plate portions 152-2 and 3 with -1 and 2 as fulcrums. Therefore, the displacement absorbing mechanism 150 ′ can absorb a more complicated mounting inclination such as a bowl-shaped warp of the semiconductor chip 130 in a movable range larger than the example of FIG. 6.

  6 and 7, the two slits 151-1 and 151-2 of each displacement absorbing mechanism 150 are substantially relative to each other and to the main body 141. It is drawn to be parallel. However, at least one of the slits 151-1 and 151-2 may have an inclination with respect to the main body 141.

  6 and 7, the protrusion 150 has been described as a quadrangular prism-shaped protrusion 150, but the protrusion 150 may have a shape of a polygonal column such as a column or a hexagonal column. Even in the projection portion having such a shape, a displacement absorbing mechanism having a desired movable direction can be configured by forming, for example, three slits from the side surface.

  Furthermore, a displacement absorbing operation with a higher degree of freedom can be realized by combining displacement absorbing mechanisms having more different axial directions and / or fulcrum positions. Conversely, when the desired displacement absorbing operation is known in advance, for example, when the warping direction of the wiring board 120 is known in advance, the manufacturing cost can be reduced by, for example, a one-stage displacement absorbing mechanism. Can do.

  Next, a modification of the semiconductor module 100 shown in FIGS. 3 and 6 will be described with reference to FIGS. In these drawings, elements corresponding to those in FIG. 3 are denoted by reference numerals in which only the first digit is changed, and redundant description is omitted.

  FIG. 8 shows a semiconductor module 200 according to the first modification. The semiconductor module 200 includes a plurality of semiconductor packages 230-1 and 2 having different package standards, particularly thickness standards, and accordingly, the heat sink 240 has a plurality of displacements having different projecting heights from the main body 241. It has absorption mechanisms 250-1 and 250-2. The semiconductor package 230-1 has a thickness larger than that of the semiconductor package 230-2, and the displacement absorbing mechanism 250-1 that is in contact with the semiconductor package 230-1 has a displacement that is in contact with the semiconductor package 230-2. It has a smaller height than the absorption mechanism 250-2. In this way, by changing the height of the displacement absorbing mechanism 250 from the beginning according to a given combination of the semiconductor devices 230, the load and thermal contact between the radiator 240 and the plurality of semiconductor devices 230 can be reduced. It becomes possible to keep more uniform.

  The slits 251 of the displacement absorbing mechanisms 250-1 and 250-2 may be formed at different height positions in the displacement absorbing mechanisms 250-1 and 250-2 as shown, but from the viewpoint of manufacturing described later. The displacement absorbing mechanisms 250-1 and 250-2 are preferably formed at the same height position.

  FIG. 9 shows a semiconductor module 300 according to the second modification. The semiconductor module 300 includes a heat conducting material 355 inserted into the slit 351 of the displacement absorbing mechanism 350. The heat conductive material 355 enhances heat conduction between the plate portions 352 vertically separated by the slits 351, and efficiently generates heat generated in the semiconductor device 330 on the heat radiation side of the heat sink 340 (for example, the main body 341 and the heat radiation). Acts to convey to the fins 342).

  For example, the heat conducting material 355 can be a grease-like thermal compound and is filled in the slit 351 by a dispenser. Alternatively, the heat conductive material 355 may be a sheet-like thermal compound, and is inserted so as to be sandwiched between the plate portions 352. These thermal compounds preferably include a heat-dissipating filler such as metal compound particles such as alumina and metal fine particles.

  Further, instead of or in addition to the thermal compound 355, another heat conductive material having elasticity, such as a metal mesh knitted with a metal wire, may be inserted into the slit 351. The metal mesh can act to further increase the heat conduction between the plate portions 352.

  FIG. 10 shows a semiconductor module 400 according to the third modification. In the semiconductor module 400, at least one of the plurality of slits 451 of the displacement absorbing mechanism 450 has a triangular cross-sectional shape, that is, from the open end 451b side to the closed end 451a in the initial state before contact with the semiconductor device 430. It has a shape whose height decreases toward the side. In the illustrated example, all the slits 451 of the displacement absorbing mechanism 450 have a triangular cross-sectional shape. Such a triangular slit 451 enables a greater amount of displacement absorption than a rectangular slit (for example, the slit 151 in FIG. 3).

  Further, when the semiconductor device 430 has a given mounting inclination due to the warp of the wiring substrate 420 or the like, the bottom surface of the lowermost plate portion is used as the main body of the heat sink 440 in combination with a triangular slit 451 or other shaped slit. You may make it incline previously with respect to a plane.

  FIG. 11 shows a semiconductor module 500 according to a fourth modification. FIG. 11A shows a cross-sectional view of the semiconductor module 500, and FIGS. 11B and 11C respectively show the lowermost plate portion 552-3 viewed from the height position of the slit 551-2. , And the bottom surface of the middle plate portion 552-2. For example, the plate portion 552-3 has a concave portion 552a on its top surface, and the plate portion 552-2 has a convex portion 552b on its bottom surface. The concave portion 552a and the convex portion 552b are formed at positions that mesh with each other when the displacement absorbing mechanism 550 contracts so that the slit 551-2 narrows, and increases the amount of displacement absorbed by the displacement absorbing mechanism 550. The plate portion 552-2 may have a concave portion on the top surface like the plate portion 552-3, and the uppermost plate portion 552-1 may have a convex portion on the bottom surface like the plate portion 552-2. It is also possible to provide a recess 552a on the top surface side of the plate portion and arrange the thermal compound or metal mesh described with reference to FIG. 8 in the recess 552a.

  Next, with reference to FIG. 12, the manufacturing method of the displacement absorption mechanism 150 which the heat radiator 140 shown in FIG. 3 etc. has is demonstrated. Here, as a preferred example, a method using a dipping-type wire electric discharge machine will be described, but other methods such as machining can also be used. FIGS. 12A and 12B schematically show a state when viewed from two side directions orthogonal to each other.

  First, the heat sink 140 on which protrusions that will become the displacement absorbing mechanism 150 are formed by machining is immersed in a dielectric 602 such as water or oil in the immersion tank 601 and preferably fixed horizontally. For example, an electrode wire 603 including a brass alloy having a diameter of 50 μm to 300 μm, tungsten, or the like is pulled out from the wire bobbin 604 and disposed at a height position where the slit 151 on the side surface of the protrusion is to be formed. Thereafter, a voltage is applied between the heat sink 140 and the electrode wire 603 by the power source 605, and a part of the heat sink 140 (Cu or Al, etc.) is melted and removed by the discharge, thereby causing the electrode wire 603 to move in the slit machining direction. Move. Then, the movement is stopped at the position where the hinge portion 153, that is, the connecting portion of the plate portion 152 adjacent to the upper and lower sides remains. Thereby, a slit 151 having a height corresponding to the diameter of the electrode wire 603 is formed. If necessary, at the closed end 151a of the slit 151, for example, a hollow portion having a diameter of about several hundred μm to 1 mm is similarly formed by electric discharge machining.

  When the plurality of slits 151 are formed, the above-described method may be repeated. When the plurality of displacement absorbing mechanisms 150 respectively in contact with the plurality of semiconductor devices have slits 151 at a common height position, as shown in FIG. 12B, some of these slits 151 are formed at the same time. Is possible. Therefore, from the viewpoint of manufacturing throughput, it is preferable that the plurality of displacement absorbing mechanisms of the radiator have a slit at a common height position.

  Although the embodiment has been described in detail above, the present invention is not limited to the specific embodiment, and various modifications and changes can be made within the scope of the gist described in the claims. For example, the various modifications described above can be applied in combination with each other as necessary. Further, the above-described embodiment is not limited to a configuration in which one (one or a plurality of stages) displacement absorbing mechanism is arranged in one semiconductor device, but for some or all semiconductor devices, for example, FIG. A plurality of displacement absorbing mechanisms such as a 2 × 2 array-like displacement absorbing mechanism in FIG. 7 may be arranged.

Regarding the above description, the following additional notes are disclosed.
(Appendix 1)
A semiconductor module comprising: a wiring board; a plurality of semiconductor devices disposed on the wiring board; and a heat dissipating body disposed on the plurality of semiconductor devices,
The heat dissipator is integrally formed with the main body that is common to the plurality of semiconductor devices, and protrudes from the main body toward the plurality of semiconductor devices so as to be in thermal contact with the plurality of semiconductor devices. A plurality of protrusions formed,
Each protrusion has a slit cut from the side surface of the protrusion so that the bottom surface of the protrusion is displaced following the corresponding upper surface of the plurality of semiconductor devices.
Semiconductor module.
(Appendix 2)
The semiconductor module according to appendix 1, wherein each protrusion has a plurality of slits formed in different planes.
(Appendix 3)
The semiconductor module according to appendix 2, wherein the plurality of slits include two slits cut from opposite directions.
(Appendix 4)
4. The semiconductor module according to appendix 2 or 3, wherein the plurality of slits include two slits cut from a direction intersecting each other.
(Appendix 5)
The semiconductor module according to appendix 4, wherein the protrusion has a quadrangular prism shape, and the plurality of slits include two slits cut from two adjacent side surfaces of the four side surfaces.
(Appendix 6)
The plurality of semiconductor devices include a first semiconductor device and a second semiconductor device having a thickness smaller than the thickness of the first semiconductor device,
The plurality of protrusions include a first protrusion that is in thermal contact with the first semiconductor device, and a second protrusion that is in thermal contact with the second semiconductor device, The protrusion height of the first protrusion from the main body is smaller than the protrusion height of the second protrusion,
The semiconductor module according to any one of appendices 1 to 5.
(Appendix 7)
The semiconductor module according to any one of appendices 1 to 6, wherein a heat conductive material is inserted into the slit.
(Appendix 8)
The semiconductor module according to appendix 7, wherein the heat conductive material includes at least one of a thermal compound and a metal mesh.
(Appendix 9)
The protrusion has a plurality of plate portions formed by the slit and connected to each other and two adjacent plate portions,
The slit has a triangular shape whose height decreases toward the connection part,
The semiconductor module according to any one of appendices 1 to 8.
(Appendix 10)
Any one of appendices 1 to 9, wherein one of the two surfaces in the protruding portion facing each other through the slit has a convex portion, and the other surface has a concave portion at a position corresponding to the convex portion. The semiconductor module described in 1.
(Appendix 11)
Each projection part is a semiconductor module as described in any one of appendix 1 thru | or 10 which has the said slit formed in the surface common to these projection parts.
(Appendix 12)
At least one of the plurality of protrusions, the lowermost plate-like portion having the bottom surface of the protrusion among the plurality of plate-like portions of the protrusion separated from each other by the plurality of slits. The semiconductor module according to any one of appendices 1 to 11, wherein the thickness of is greater than the thickness of the other plate-like portion.
(Appendix 13)
Any one of appendices 1 to 12, wherein, in at least one of the plurality of protrusions, the bottom surface of the protrusion is inclined with respect to the upper surface of the protrusion that forms a boundary with the main body. The semiconductor module described in 1.

100, 200, 300, 400, 500 Semiconductor module 120, 220, 320, 420, 520 Wiring board 130, 230, 330, 430, 530 Semiconductor device 134 Connection terminal 136 Heat dissipation surface 140, 240, 340, 440 of semiconductor device, 540 Radiator 141, 241, 341 Radiator body 150, 250, 350, 450, 550 Radiator protrusion (displacement absorbing mechanism)
151, 251, 351, 451, 551 Slit 151 a, 451 a Slit closed end 151 b, 451 b Slit open end 152, 352, 552 Plate part 153, 553 Connection (hinge) part 355 Heat conduction material 160 Reinforcement plate 161 Fixing means 552 a Concave portion 552b Convex portion 601 Immersion tank 602 Dielectric (water or oil, etc.)
603 Electrode wire 604 Wire bobbin 605 Power supply

Claims (5)

A semiconductor module comprising: a wiring board; a plurality of semiconductor devices disposed on the wiring board; and a heat dissipating body disposed on the plurality of semiconductor devices,
The heat dissipator is integrally formed with the main body that is common to the plurality of semiconductor devices, and protrudes from the main body toward the plurality of semiconductor devices so as to be in thermal contact with the plurality of semiconductor devices. A plurality of protrusions formed,
Each protrusion has a slit cut from the side surface of the protrusion so that the bottom surface of the protrusion is displaced following the corresponding upper surface of the plurality of semiconductor devices.
Semiconductor module.   The semiconductor module according to claim 1, wherein each protrusion has a plurality of slits formed in different planes.   The semiconductor module according to claim 2, wherein the plurality of slits include two slits cut from directions intersecting each other. The plurality of semiconductor devices include a first semiconductor device and a second semiconductor device having a thickness smaller than the thickness of the first semiconductor device,
The plurality of protrusions include a first protrusion that is in thermal contact with the first semiconductor device, and a second protrusion that is in thermal contact with the second semiconductor device, The protrusion height of the first protrusion from the main body is smaller than the protrusion height of the second protrusion,
The semiconductor module as described in any one of Claims 1 thru | or 3.   The semiconductor module according to claim 1, wherein a heat conductive material is inserted into the slit.