JP2009164152A - Laminated semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayer type semiconductor device having enhanced dissipation efficiency of heat generated on respective substrates. <P>SOLUTION: The multilayer type semiconductor device has a plurality of semiconductor chips 12 stacked at intervals, wherein thermally conductive members 16 for improving thermal conductivity between the semiconductor chips 12 are disposed between the semiconductor chips 12. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a stacked semiconductor device formed by stacking a plurality of substrates.

  Conventionally, for example, a stacked semiconductor device formed by stacking and bonding substrates provided with circuit elements is known (see, for example, Patent Document 1).

According to this stacked semiconductor device, for example, the number of substrates to be mounted can be increased without increasing the mounting area of the electronic device.
JP 11-261000 A

  However, since a plurality of substrates are stacked, when heat is generated in each of the substrates arranged in the central portion in the stacking direction, it is difficult for the heat to be discharged to the outside of the stacked semiconductor device.

  In particular, when an adhesive called an underfill made of a synthetic resin for adhering each substrate adjacent to each other is filled between the substrates, the underfill conducts heat in the gap between the substrates. Therefore, it becomes difficult to exhaust the heat of each substrate to the outside of the stacked semiconductor device. If the heat is discharged to each substrate without discharging the heat from each substrate, an abnormal operation of a circuit formed on each substrate or damage to each substrate is caused.

  Therefore, an object of the present invention is to provide a stacked semiconductor device that can improve the efficiency of discharging heat generated in each substrate.

  In order to solve the above-described problem, a stacked semiconductor device according to the present invention is a stacked semiconductor device including a plurality of substrates that are stacked with a space between each of the substrates. The heat conductive member for improving the heat conductivity in is arrange | positioned.

  According to the present invention, since the heat conductive member for improving the thermal conductivity between the substrates is disposed between the stacked substrates, the heat is generated when heat is generated in the substrates. It can be easily absorbed by the heat conductive member. Thus, the heat of each substrate can be easily discharged from between the substrates to the outside of the stacked semiconductor device via the heat conductive member. Therefore, compared with the case where the underfill made of a synthetic resin is filled between the substrates, the heat discharge efficiency of each substrate is reliably improved.

  In order to solve the above problems, a stacked semiconductor device according to the present invention is a stacked semiconductor device including a plurality of stacked substrates, and each substrate is placed in the stacking direction. A continuous through-hole is formed, and a thermal conductive member for improving the thermal conductivity in the through-hole is disposed in the through-hole.

  According to the present invention, the heat conductive member for improving the thermal conductivity in the through hole is disposed in the through hole that continuously passes through the stacked substrates in the stacking direction. When heat is generated in each substrate, the heat conductive member can easily absorb the heat. As a result, regardless of whether or not the underfill made of synthetic resin is filled between the substrates and whether or not a gap is formed between the substrates, the heat of each substrate is thermally conductive. It can be transmitted in the stacking direction of each substrate by the member. Therefore, the heat of each substrate can be easily discharged from the stacked semiconductor device to the outside through the heat conductive member.

  According to the present invention, it is possible to reliably improve the efficiency of discharging heat generated in each substrate as compared with the conventional case. It is possible to reliably prevent the occurrence of damage.

  Hereinafter, the present invention will be described with reference to the illustrated embodiments.

  As shown in FIG. 1, the stacked semiconductor device 10 according to the present invention includes a plurality of substrates 12 stacked in the vertical direction with an interval therebetween.

  Each substrate 12 is composed of a semiconductor chip 12 in the illustrated example. As is well known, each semiconductor chip 12 is a substrate on which circuit elements such as transistors, resistors, and capacitors are formed. A circular wafer made of single crystal silicon, which is a semiconductor material, is cut. It is formed by separating.

  Each semiconductor chip 12 is formed with a plurality of connection portions (not shown) for connecting the semiconductor chips 12 arranged adjacent to each other. Each of the connection portions is provided on the lower surface 12a of each semiconductor chip 12, for example, and protrudes from the lower surface. When the semiconductor chips 12 are connected by the connection portions, a gap S having a size substantially equal to the protruding amount of the connection portions is formed between the semiconductor chips 12. The size of each gap S is 2 μm to 30 μm in the illustrated example.

  In the illustrated example, a microprocessor 14 (hereinafter referred to as MPU) is disposed below the semiconductor chip 12 constituting the lowermost layer of each semiconductor chip 12. In the illustrated example, the MPU 14 is in contact with the lower surface 12a of the lowermost semiconductor chip 12 at the upper surface 14a.

  Further, in the illustrated example, a heat sink 15 for absorbing and radiating heat generated in each semiconductor chip 12 and the MPU 14 is disposed above the semiconductor chip 12 constituting the uppermost layer. The heat sink 15 is a plate member made of a metal having high thermal conductivity such as aluminum or copper, and is disposed so as to contact the uppermost semiconductor chip 12.

  In the gaps S between the semiconductor chips 12, thermal conductive members 16 are arranged for improving the thermal conductivity in the gaps.

  The thermally conductive member 16 is disposed so as to fill the gap S between the semiconductor chips 12, and is composed of a diamond thin film 16 in the illustrated example.

  The diamond thin film 16 is formed by, for example, a microwave plasma CVD method. By forming the diamond thin film 16 in each gap S, the gap S is filled with the diamond thin film 16.

  In the present embodiment, each semiconductor chip 12 and each diamond thin film 16 extend in the plate thickness direction of the semiconductor chip 12, that is, the stacking direction of the semiconductor chips 12, and a plurality of penetrations that continuously penetrate each semiconductor chip 12 and the diamond thin film 16. A hole 17 is formed.

  The diameter of each through hole 17 is set to about 100 nm in the illustrated example. One end 17a of each through hole 17 is open to the lower surface 12a of the semiconductor chip 12 constituting the lowermost layer. The other end 17b of each through hole 17 is open to the upper surface 12b of the semiconductor chip 12 constituting the uppermost layer. As a result, the MPU 14 and the heat sink 15 are partially exposed in the respective through holes 17.

  In general, the MPU 14 has a plurality of hot spots 14b that are portions where the temperature is higher than other portions when the MPU 14 is operated. As is well known in the art, the hot spot 14b is a part where a control circuit for controlling the operation of each part provided in the MPU 14, for example, is arranged. In the illustrated example, each through hole 17 is formed such that one end 17a is positioned in the vicinity of each hot spot 14b of the MPU 14.

  Each through-hole 17 is formed in each semiconductor chip 12 and each diamond thin film 16 by using, for example, well-known deep reactive ion etching (DRIE), a beam, and a micro drill.

  In each through hole 17, a thermal conductive member 18 for through hole is arranged for improving the thermal conductivity in each through hole.

  The through hole heat conductive member 18 is disposed so as to fill each through hole 17. In the illustrated example, the through hole heat conductive member 18 is composed of a plurality of metal particles.

  For the metal particles, it is desirable to use a metal having a relatively high thermal conductivity among many known metals such as gold and copper.

  Moreover, it is desirable to use the nanoparticle whose magnitude | size is a nanometer order for a metal particle. In general, a nanoparticle is easily bonded to another nanoparticle by an intermolecular force acting between the nanoparticle and another nanoparticle, so that a lump composed of the nanoparticles is easily formed. Therefore, by using nanoparticles as the metal particles, the metal particles can be easily filled without forming a large gap in each through-hole 17.

  When each semiconductor chip 12 generates heat, most of the heat of each semiconductor chip 12 is given to the diamond thin film 16 in each gap S from each semiconductor chip. When heat is applied to the diamond thin film 16, the heat is propagated very efficiently by phonon vibration of the covalent bond between the carbon atoms forming the diamond thin film 16. Thereby, the heat of each semiconductor chip 12 is transferred to the side of the stacked semiconductor 10 from each gap S by being transmitted through the diamond thin film 16 toward the side of the stacked semiconductor device 10.

  A part of the heat of the semiconductor chip 12 constituting the uppermost layer is transmitted to the heat sink 15 in contact with the semiconductor chip, and then released from the heat sink.

  Further, a part of the heat generated in each semiconductor chip 12 is transmitted from each generated semiconductor chip 12 directly or through the diamond thin film 16 to the through hole heat conductive member 18 in each through hole 17. A part of the heat transferred to the through hole heat conductive member 18 in each through hole 17 is sequentially transferred upward through the plurality of metal particles that are the through hole heat conductive member, thereby each through hole. 17 is discharged upward from the inside. The heat released upward from each through-hole 17 is transferred to the heat sink 15 and then released from the heat sink.

  When the MPU 14 generates heat, most of the heat generated in each hot spot 14b of the MPU 14 is released upward from the region corresponding to each hot spot 14b on the upper surface 14a of the MPU 14. At this time, since one end 17a of each through-hole 17 is located in the vicinity of each hot spot 14b of the MPU 14 as described above, most of the heat generated in each hot spot 14b is obtained from each through-hole 17b. It is discharged through its one end 17a. The heat released into each through-hole 17 is transmitted upward to the heat conductive member 18 for through-holes in each through-hole 17 and then transmitted to the heat sink 15 and released from the heat sink. Thereby, the heat | fever of the hot spot 14b used as the highest temperature among the parts of MPU14 can be efficiently discharged | emitted from MPU14.

  Further, part of the heat generated in the MPU 14 is transmitted to the semiconductor chip 12 constituting the lowermost layer. As described above, the heat transferred to the semiconductor chip 12 is in the diamond thin film 16 in the gap S between the lowermost semiconductor chip 12 and the semiconductor chip 12 adjacent to the semiconductor chip, and in each through hole 17. The plurality of metal particles that are the through hole thermal conductive members 18 are sequentially transmitted to the outside of the stacked semiconductor device 10.

  Thereby, since the heat generated in the MPU 14 can be efficiently discharged, an increase in the temperature of the MPU 14 can be suppressed. Therefore, abnormal operation and damage of the MPU 14 due to the temperature of the MPU 14 exceeding the allowable maximum temperature can be reliably prevented.

  According to the present embodiment, as described above, the thermal conductive member 16 for improving the thermal conductivity in the gap is disposed in the gap S between the stacked semiconductor chips 12. When heat is generated in each semiconductor chip 12, the heat conductive member 16 can easily absorb the heat.

  Thus, the heat of each semiconductor chip 12 can be easily discharged from between the semiconductor chips 12 to the outside of the stacked semiconductor device 10 via the heat conductive member 16. Compared with the case where the underfill made of such a synthetic resin is filled, the heat discharge efficiency of each semiconductor chip 12 is reliably improved.

  Accordingly, it is possible to reliably prevent the abnormal operation of the circuit of each semiconductor chip or the damage of each semiconductor chip 12 caused by the heat of each semiconductor chip 12 being applied to each semiconductor chip.

  Further, as described above, in the plurality of through holes 17 formed through the semiconductor chips 12 and the diamond thin films 16, the through holes for improving the thermal conductivity in the through holes are provided. A thermally conductive member 18 is disposed. From this, the heat generated in each semiconductor chip 12 can be discharged to the side of the stacked semiconductor device 10 by the heat conductive member 16 between the semiconductor chips 12, and in addition, the penetration in the through hole 17. The heat conductive member 18 for holes can be discharged upward or downward of the stacked semiconductor device 10. Thereby, the efficiency of discharging the heat generated in each semiconductor chip 12 can be further improved.

  Further, since the heat conductive member 16 is filled in the gap S between the semiconductor chips 12, when a load is applied to the stacked semiconductor device 10 in the stacking direction of the semiconductor chips 12, the external force is applied to each semiconductor chip. The heat conductive member 16 is received as a compressive force for compressing the heat conductive member 16 in the gap S between the chips 12. As a result, the stacked semiconductor device 10 is secured with respect to the load acting in the stacking direction of the semiconductor chips 12.

  In this embodiment, an example in which the heat conductive member 16 is formed of a diamond thin film has been shown. Instead, as shown in FIG. 2, a plurality of cylindrical carbon nanotubes 19 (hereinafter referred to as CNT) are used. ) Can constitute the heat conductive member 16.

  As is well known, the CNT 19 is a fibrous carbon material having a diameter of about 0.5 to 2.0 nm and a length of about 1 to 100 μm. Further, the CNT 19 has a thermal conductivity higher than that of diamond. The CNT 19 includes single-walled CNTs and multi-walled CNTs such as double-walled CNTs and triple-walled CNTs, and there are a plurality of types having different crystal structures and diameters. The conductivity is different. In this embodiment, among such many types, CNT 19 having low conductivity is used.

  When each semiconductor chip 12 generates heat, most of the heat of each semiconductor chip 12 is given to the plurality of CNTs 19 in each gap S from each semiconductor chip. When heat is applied to the CNT 19 from each semiconductor chip 12, lattice vibration occurs in the CNT 19. Thereby, the heat of each semiconductor chip 12 is transmitted between the CNTs 19 even if the CNTs 19 are not in contact with each other. Heat transferred to the side of the stacked semiconductor device 10 between the plurality of CNTs 19 in each gap S is released from the inside of each gap S to the side of the stacked semiconductor 10.

  A part of the heat of the semiconductor chip 12 constituting the uppermost layer is transmitted to the heat sink 15 in contact with the semiconductor chip, and then released from the heat sink.

  Further, a part of the heat generated in each semiconductor chip 12 is transmitted from the generated semiconductor chip 12 directly or through the plurality of CNTs 19 to the through hole thermal conductive member 18 in each through hole 17. The heat transferred to the through hole thermal conductive member 18 in each through hole 17 is transferred to the heat sink 15 through the through hole thermal conductive member and then released from the heat sink.

  According to the example shown in FIG. 2, as described above, even if the plurality of CNTs 19 are separated from each other, heat is transferred by lattice vibration of the CNTs. From this, it is possible to reliably improve the thermal conductivity in each gap S as compared to the case of simply injecting a synthetic resin material into each gap S as in the prior art.

  Moreover, since heat is transmitted by the lattice vibration of each CNT, heat can be reliably transmitted regardless of the arrangement of the CNTs 19 in each gap S. Thereby, since it is not necessary to make the plurality of CNTs 19 contact each other, compared to the case where the thermal conductive material such as the plurality of CNTs 19 is inserted into each gap S and then the thermal conductive material is contacted. The heat conductive member 16 can be easily disposed in each gap S.

  Furthermore, according to the example shown in FIG. 2, since the CNTs 19 having low conductivity are used, it is possible to reliably suppress each semiconductor chip 12 from being electrically connected by each CNT 19.

  In the example shown in FIG. 2, an example in which a plurality of metal particles is used for the through hole thermal conductive member 18 in each through hole 17 is shown, but instead of this, for through holes other than the plurality of metal particles. A thermally conductive member 18 can be used.

  In the example shown in FIG. 2, when inserting a plurality of CNTs 19 into each gap S, the CNTs 19 may be arranged so that the axis of each CNT 19 faces in a direction perpendicular to the thickness direction of each semiconductor chip 12 by dielectrophoretic force. it can.

  In this case, for example, a dielectrophoresis apparatus 20 as shown in FIG. 3 is used. The dielectrophoresis apparatus 20 includes a pair of electrode plates 21 and 22 and an AC power source 23 for applying an AC voltage to each electrode plate. Each of the electrode plates 21 and 22 is disposed so as to sandwich the stacked semiconductor device from both sides of the stacked semiconductor device 10.

  By operating the AC power supply 23 in a state where the stacked semiconductor device 10 before the formation of the plurality of through holes 17 is immersed in the solution 24 in which the plurality of CNTs 19 are dispersed, both the electrode plates 21 and 22 are operated. An AC voltage is applied between them. Thereby, a force based on the principle of dielectrophoresis is applied to the plurality of CNTs 19 in the solution 24.

  That is, when an electric field is applied to the solution 24 in which a plurality of CNTs 19 are dispersed, an induced dipole moment is generated due to a difference in polarizability between the solution 24 and each CNT 19, and a difference in electric field strength formed on both sides of each CNT 9 is generated. The force acts on each CNT 19 as a difference in force exerted by the induced dipole. It is known that the dielectrophoretic force FDEP acting at this time is expressed by the following equation.

^{_{F DEP = 2πε m a 3 Re}} [(ε p - ε m) / (ε p +2 ε m)] ∇E 2 ... (1) Equation (1) in, a is the CNT19 radius [m], ε Represents a dielectric constant [F / m], and subscripts p and m represent CNT 19 and a solution 24 mixed with the CNT, respectively. E is the electric field (V / m), and Re [f (x)] is an operator that extracts only the real part of the complex number f (x). ε is a complex dielectric constant defined by ε = ε− (σ / ω) j (2). σ is conductivity [S / m], ω (= 2πf) is angular frequency [Hz], and f is applied frequency [Hz]. j is an imaginary unit. The content of Re [] in the formula (1) is called a Clausius-Mossotti factor (CM factor: K (ω)) and represents the degree of polarization.

K (ω) = ( ε _p −ε _m ) / ( ε _p +2 ε _m ) (3) According to the equations (2) and (3), this CM factor is the conductivity of the solution 24 and each CNT 19. Depending on the dielectric constant and the frequency of the applied voltage, it takes a value of -0.5 to 1.0. According to equation (1), the direction of dielectrophoretic force depends on the CM factor. That is, when the real part of the CM factor is positive, the dielectrophoretic force is positive, and each CNT 19 is subjected to positive dielectrophoresis that induces the CNT 19 in the direction where the electric field strength is larger. On the other hand, when the real part of the CM factor is negative, the dielectrophoretic force is negative, and a negative dielectrophoretic force that induces the CNT 19 to the weaker electric field strength acts.

  Therefore, when a voltage is applied to each electrode plate 21, 22 and the electric field strength in each gap S is stronger than the electric field strength outside each gap S, a positive dielectrophoretic force acts on each CNT 19. The frequency of the applied voltage is set so that On the other hand, when the electric field strength in each gap S is weaker than the electric field strength outside each gap S, the frequency of the applied voltage is set so that a negative dielectrophoretic force acts on each CNT 19. Thereby, each CNT 19 dispersed in the solution 24 is inserted into each gap S by the dielectrophoretic force. At this time, one end of each CNT 19 is pulled toward each gap S by the dielectrophoretic force, so that each CNT 19 inserted in each gap has its axis line in the thickness direction of each semiconductor chip 12. It arrange | positions so that it may face in the orthogonal direction.

  According to the example shown in FIG. 3, as described above, the plurality of CNTs 19 are arranged so as to face the direction orthogonal to the plate thickness direction of each semiconductor chip 12 by the dielectrophoretic force. From this, the heat transfer direction in each gap S can be one direction. In CNT, heat is propagated by phonon vibration and π electrons. That is, heat flows along the graphene wall. Therefore, arranging the individual CNTs in the major axis direction is the most efficient in transferring heat. As heat propagates through the graphene wall of each CNT 19, heat can be transported out of the system more efficiently than when a plurality of CNTs 19 are arranged in irregular directions. Thereby, the thermal conductivity in each gap | interval S can be improved more reliably.

  In addition, since all the CNTs 19 are oriented in a direction perpendicular to the thickness direction of the respective semiconductor chips 12, the CNTs 19 are prevented from being disposed across the respective semiconductor chips 12. Thereby, even if each of the plurality of CNTs 19 has high conductivity, it is possible to reliably prevent the semiconductor chips 12 from being electrically connected to each other by the CNTs 19.

  In the example shown in FIG. 1 to FIG. 3, the example in which the heat conductive member 16 is composed of a diamond thin film and a plurality of CNTs 19 is shown, but instead of this, heat conduction is performed with a synthetic resin material in which a plurality of CNTs 19 are mixed. The sex member 16 can be configured.

  In this case, for example, an epoxy resin can be used as the synthetic resin material into which the plurality of CNTs 19 are mixed. A synthetic resin material mixed with a plurality of CNTs is filled into each gap S by being injected into each gap S in a state where fluidity is ensured and then cured.

  Further, in this case, by replacing the solvent 24 with a liquid synthetic resin material, each axis line of each CNT 19 mixed in the synthetic resin material injected into each gap S is similar to the example shown in FIG. It can arrange | position so that it may face the direction orthogonal to the plate | board thickness direction of each semiconductor chip 12. FIG.

  Moreover, in the example shown in FIGS. 1 to 3, the example in which the heat conductive member 16 is composed of the diamond thin film 16 or the plurality of CNTs 19 is shown, but instead, as shown in FIGS. 4 and 5, The thermally conductive member 16 can be constituted by a plurality of granular members 27 in which the CNTs 26 are wrapped with a synthetic resin material 25 having no electrical conductivity.

  As shown in FIG. 5, each granular member 27 is formed by embedding a plurality of CNTs 26 in a synthetic resin material 25 formed in a granular shape. Each granular member 27 is formed by kneading CNT 26 and a resin raw material. For the synthetic resin material 25, for example, acrylic resin, styrene resin, PET resin, butadiene resin, and phenol resin are used.

  When each semiconductor chip 12 generates heat, most of the heat of each semiconductor chip 12 is applied to the plurality of granular members 27 in each gap S from each semiconductor chip. At this time, when heat is applied to each CNT 26 of each granular member 27 from each semiconductor chip 12 via the synthetic resin material 25, lattice vibration occurs in each CNT 26. Thereby, even if the heat of each semiconductor chip 12 is separated without contacting each CNT 26, the heat is transferred between the CNTs 26 in each granular member 27, and further, between each CNT 26 between each granular member 27. Communicated. The heat sequentially transmitted between the granular members 27 in each gap S toward the side of the stacked semiconductor device 10 is released from the gap S to the side of the stacked semiconductor device 10.

  A part of the heat of the semiconductor chip 12 constituting the uppermost layer is transmitted to the heat sink 15 in contact with the semiconductor chip, and then released from the heat sink.

  Further, a part of the heat generated in each semiconductor chip 12 is directly transmitted from each generated semiconductor chip 12 or through each CNT 26 of each granular member 27 to the through hole heat conductive member 18 in each through hole 17. It is transmitted. The heat transferred to the through hole thermal conductive member 18 in each through hole 17 is transferred to the heat sink 15 through the through hole thermal conductive member and then released from the heat sink.

  According to the example shown in FIGS. 4 and 5, since the plurality of CNTs 26 are covered with the synthetic resin material 25 having no electrical conductivity, the CNTs 26 straddle between the semiconductor chips 12 adjacent to each other. The CNTs 26 are not arranged, and the CNTs 26 do not come into contact between the granular members 27. Thereby, even if each CNT 26 of each granular member 27 has high conductivity, each semiconductor chip 12 is reliably suppressed from being electrically connected by each CNT 26 of each granular member 27. be able to.

  In the example shown in FIGS. 4 and 5, in order to prevent electrical conduction between the semiconductor chips 12 and improve the thermal conductivity, a plurality of CNTs 26 wrapped with a synthetic resin material 25 having no electrical conductivity are used. Although the example which used the granular member 27 for the heat conductive member 16 was shown, it can replace with this and the heat conductive member 16 as shown in FIG. 6 can be used for this invention.

  In the example shown in FIG. 6, the heat conductive member 16 is formed by embedding a plurality of blocks 37 formed by solidifying a plurality of CNTs in a sheet member 36 made of a synthetic resin material having no electrical conductivity. Is done.

  In the illustrated example, each block 37 is disposed at the center in the thickness direction without being exposed from the upper surface 36 a and the lower surface 36 b of the sheet member 36, and is orthogonal to the stacking direction of the semiconductor chips 12. Are arranged at predetermined intervals.

  According to the example shown in FIG. 6, the heat generated in each semiconductor chip 12 is transmitted between the blocks 37 by the lattice vibration of the CNT constituting each block 37 in the sheet member 36. The heat sequentially transferred in the sheet member 36 toward the side of the stacked semiconductor device 10 is released from the gaps S to the side of the stacked semiconductor device 10.

  In addition, since the plurality of blocks 37 made of CNT are covered with a synthetic resin material having no electrical conductivity, the blocks 37 are not arranged so as to straddle between the adjacent semiconductor chips 12. In addition, the blocks 37 do not come into contact between the semiconductor chips 12. Thereby, even if the CNTs of the respective blocks 37 have high conductivity, it is possible to reliably prevent the semiconductor chips 12 from being electrically connected to each other by the CNTs of the respective blocks 37.

  Further, when the stacked semiconductor device 10 is formed, since the sheet member 36 can be sandwiched between the semiconductor chips when the semiconductor chips 12 are stacked, the heat conductive member 16 between the semiconductor chips 12 is formed. Arrangement work can be performed more easily.

  In the example shown in FIG. 6, each block 37 is arranged at the center in the thickness direction without being exposed from the upper surface 36 a and the lower surface 36 b of the sheet member 36. Can be disposed so as to be exposed from either one of the upper surface 36a and the lower surface 36b of the sheet member 36, respectively. In this case, even if each block 37 exposed from the upper surface 36a or the lower surface 36b contacts one of the adjacent semiconductor chips 12, the respective semiconductor chips are not electrically connected to each other.

  In the example shown in FIGS. 4 and 6, an example in which a plurality of metal particles is used for the thermal conductive member 18 for the through hole in each through hole 17 is shown, but instead of this, other than the plurality of metal particles The heat conductive member 18 for through-holes can be used.

  In the example shown in FIG. 1 to FIG. 6, the example in which the through hole heat conductive member 18 filled in each through hole 17 is composed of a plurality of metal particles is shown. As shown, the through hole heat conductive member 18 can be formed of a plurality of CNTs 28.

  In this case, part of the heat generated in each semiconductor chip 12 is released into each through-hole 17 directly from each generated semiconductor chip 12 or through the heat conductive member 16 in each gap S. At this time, each CNT 28 filled in each through-hole 17 is given heat released into each through-hole 17. When heat is applied to the CNTs 28, the heat of each semiconductor chip 12 is transmitted between the CNTs 28 even if the CNTs 28 are not in contact with each other due to lattice vibration of the CNTs 28. The heat that is sequentially transmitted upward in each through-hole 17 from each CNT 28 is released from the inside of each through-hole 17 upward. The heat released upward from each through-hole 17 is transferred to the heat sink 15 and then released from the heat sink.

  When the MPU 14 generates heat, most of the heat generated in each hot spot 14b of the MPU 14 is released upward from the region corresponding to each hot spot 14b on the upper surface 14a of the MPU 14. At this time, since one end 17a of each through-hole 17 is located in the vicinity of each hot spot 14b of the MPU 14 as described above, most of the heat generated in each hot spot 14b is obtained from each through-hole 17b. It is discharged through its one end 17a. The heat released into each through-hole 17 is sequentially transmitted upward through each CNT 28 in each through-hole 17 and then transmitted to the heat sink 15 and released from the heat sink.

  In the example shown in FIG. 7, when a plurality of CNTs 28 are packed in each through-hole 17, each CNT 28 is arranged in the through-hole so that the axis of each CNT 28 faces the extending direction of each through-hole by dielectrophoretic force. be able to.

  In this case, for example, a dielectrophoresis device 29 as shown in FIG. 8 is used. The dielectrophoresis device 29 includes a pair of electrodes 30 and 31 and an AC power source 32 for applying an AC voltage to each electrode plate. Each of the electrodes 30 and 31 is disposed so as to sandwich the stacked semiconductor device from above and below the stacked semiconductor device 10.

  As in the example shown in FIG. 3, the AC power supply 32 is operated in a state where the stacked semiconductor device 10 in which the plurality of through holes 17 are formed is immersed in the solution 33 in which the plurality of CNTs 28 are dispersed. Thus, an AC voltage is applied between the electrodes 30 and 31. Thereby, a dielectrophoretic force is applied to the plurality of CNTs 28 in the synthetic resin material. As the solution 33 in which the plurality of CNTs 28 are dispersed, for example, pure water (deionized water) or a solution in which pure water contains a surfactant such as tween 20 (registered trademark) is used. it can.

  When a voltage is applied to the electrodes 30 and 31 and the electric field strength in each through-hole 17 is stronger than the electric field strength outside each through-hole 17, a positive dielectrophoretic force acts on each CNT 28. The frequency of the applied voltage is set so that On the other hand, when the electric field strength in each through hole 17 is weaker than the electric field strength outside each through hole 17, the frequency of the applied voltage is set so that a negative dielectrophoretic force acts on each CNT 28. Thereby, each CNT 28 mixed in the solution 33 is inserted into each through-hole 17 by the dielectrophoretic force. At this time, one end of each CNT 28 is pulled into each through-hole 17 by the dielectrophoretic force, so that each CNT 28 inserted into each through-hole 17 has its axis line extending in the direction of each through-hole 17. It is arranged to face.

  According to the example shown in FIG. 8, the plurality of CNTs 28 are arranged so as to face the extending direction of each through-hole 17 by the dielectrophoretic force. From this, the heat transfer direction in each gap S can be one direction. In CNT, heat is propagated by phonon vibration and π electrons. That is, heat flows along the graphene wall. Therefore, arranging the individual CNTs in the major axis direction is the most efficient in transferring heat. As heat propagates through the graphene wall of each CNT 19, heat can be transported out of the system more efficiently than when a plurality of CNTs 19 are arranged in irregular directions. Thereby, the thermal conductivity in each gap | interval S can be improved more reliably.

  In the example shown in FIGS. 7 and 8, an example in which a plurality of CNTs 28 are simply packed in each through-hole 17 is shown, but instead, a plurality of CNTs 34 are grown in each through-hole 17 to allow each through-hole 17 to grow. The holes 17 can be filled.

  When growing a plurality of CNTs 34 in each through hole 17, for example, after depositing Fe fine particles and Co fine particles having a particle diameter of several nanometers at one end a of each through hole 17, a hydrocarbon gas such as methane and ethylene, Alternatively, the CNTs 34 are grown by thermal CVD while introducing alcohol vapor. By growing a plurality of CNTs 34 from one end 17 a toward the other end 17 b in each through hole 17, each axis is arranged in the through hole so as to face the extending direction of the through hole 17, and from the MPU 14 to the heat sink 15. A plurality of CNTs 34 are formed.

  According to this example, by growing a plurality of CNTs 34 in each through hole 17, it is possible to easily fill the CNTs 34 in a very small hole of about 100 nm.

  In the example shown in FIGS. 1 to 8, the example in which the gap S between the semiconductor chips 12 and the inside of each through hole 17 are filled with the members for improving the thermal conductivity is shown. Thus, the through hole heat conductive member 18 in each through hole 17 can be dispensed with.

  In this case, in each through-hole 17, an underfill material made of a synthetic resin, which has been conventionally used to secure the strength of the stacked semiconductor device 10 along the stacking direction of each semiconductor chip 12, is provided between the semiconductor chips 12. Can be filled.

  In the example shown in FIGS. 1 to 8, an example in which a plurality of through holes 17 are formed in each semiconductor chip 12 and the heat conductive member 16 is shown. Instead, as shown in FIG. 9. Each through-hole 17 can be made unnecessary.

  In this case, part of the heat generated in each semiconductor chip 12 and MPU 14 is discharged to the outside of the stacked semiconductor device 10 through the heat conductive member 16 in each gap S. Further, part of the heat generated in each semiconductor chip 12 and MPU 14 reaches the heat sink 15 through the heat conductive member 16 and each semiconductor chip 12 in each gap S, and from the heat sink to the stacked semiconductor device 10. It is discharged outward.

  Further, in the example shown in FIGS. 1 to 9, the example in which the heat conductive member 16 is arranged in the gap S between the semiconductor chips 12 is shown, but instead of this, as shown in FIG. The heat conductive member 16 in S can be dispensed with.

  In this case, in each gap S, an underfill material 35 made of a synthetic resin, which has been conventionally used to secure the strength of the stacked semiconductor device 10 in the stacking direction of the semiconductor chips 12, is interposed between the semiconductor chips 12. Can be filled.

  Further, in this case, the heat generated in each semiconductor chip 12 and MPU 14 is discharged from the heat sink to the outside of the stacked semiconductor device 10 through the through hole thermal conductive member 18 and the heat sink 15 in each through hole 16. Is done.

  Further, when the heat conductive member 16 in each gap S is not required, each semiconductor can be formed without forming the gap S between the semiconductor chips 12 by eliminating the connection portion as shown in FIG. Chips 12 can be stacked.

  In this case, each semiconductor chip 12 can be connected by fusing the adjacent semiconductor chips 12 in place of the connection by the connecting portion.

  According to the example shown in FIGS. 10 and 11, each through-hole 17 has a through-hole heat conductive member 18 for improving the thermal conductivity in the through-hole. When heat is generated in the chip 12, the heat can be easily absorbed by the heat conductive member 18 for the through hole. Accordingly, regardless of whether or not the conventional underfill made of a synthetic resin is filled between the semiconductor chips 12 and whether or not the gap S is formed between the semiconductor chips 12. Since the heat of each semiconductor chip 12 can be transmitted to the stacking direction of each semiconductor chip 12 by the through hole thermal conductive member 18, the heat of each semiconductor chip 12 is transmitted through the through hole thermal conductive member 18. The stacked semiconductor device 10 can be easily discharged to the outside.

  In the example shown in FIGS. 10 and 11, an example in which a plurality of metal particles is used for the thermal conductive member 18 for the through hole in each through hole 17 is shown, but instead of this, other than the plurality of metal particles The heat conductive member 18 for through-holes can be used.

  In the example shown in FIGS. 1 to 11, an example in which the diameters of the through holes 17 are the same is shown. Instead, for example, the through holes 17 arranged in the vicinity of the hot spot 14 b of the MPU 14 are used. The diameter can be made larger than each other through-hole 17.

  In this case, each through-hole 17 in the vicinity of the hot spot 14b can increase the amount of heat that can be taken per unit time, so that the heat generated by the hot spot 14b can be discharged in a shorter time.

  Further, in the example shown in FIGS. 1 to 11, the number of through holes 17 arranged in the vicinity of the hot spot 14b of the MPU 14 can be increased.

  In this case, since more heat can be taken into the hot spot 14b into the through hole 17, the heat generated in the hot spot 14b can be discharged in a shorter time.

  Further, in the example shown in FIGS. 1 to 11, the example in which each through hole 17 is arranged in the vicinity of the hot spot 14 b of the MPU 14 is shown, but instead of this, or in addition to this, each semiconductor chip Each through-hole can be formed so that each through-hole 17 is arranged in the vicinity of each of the high-temperature portions of 12, the high-temperature portion of the semiconductor chip having the highest temperature among the semiconductor chips 12, and the like.

  In the example shown in FIGS. 1 to 11, the MPU 14 is disposed below the stacked semiconductor device 10, but instead of this, an LSI or an IC other than the MPU 14 is mounted below the stacked semiconductor device 10. Can be arranged.

1 is a longitudinal sectional view schematically showing a stacked semiconductor device according to the present invention. It is a longitudinal cross-sectional view which shows roughly the example by which CNT was inserted in the gap | interval between each semiconductor chip which concerns on this invention. It is explanatory drawing which shows schematically the dielectrophoresis apparatus which concerns on this invention. It is a longitudinal cross-sectional view which shows roughly the example by which the granular member formed by wrapping CNT in a synthetic resin was inserted in the gap | interval between each semiconductor chip which concerns on this invention. It is explanatory drawing which shows schematically the granular member which concerns on this invention. It is a longitudinal cross-sectional view which shows roughly the example by which the sheet | seat member was used for the heat conductive member which concerns on this invention. It is a longitudinal cross-sectional view which shows roughly the example by which CNT was inserted in each through-hole which concerns on this invention. It is explanatory drawing which shows roughly the dielectrophoresis apparatus different from the example shown in FIG. FIG. 9 is a longitudinal sectional view schematically showing a stacked semiconductor device according to an embodiment different from the examples shown in FIGS. 1 to 8. FIG. 10 is a longitudinal sectional view schematically showing a stacked semiconductor device according to an embodiment different from the examples shown in FIGS. 1 to 9. FIG. 11 is a longitudinal sectional view schematically showing a stacked semiconductor device according to another embodiment different from the examples shown in FIGS. 1 to 10.

Explanation of symbols

10 Stacked Semiconductor Device 12 Substrate (Semiconductor Chip)
16 Thermal conductive member 17 Through hole 18 Thermal conductive member for through hole 19, 26, 28 Carbon nanotube 27 Granular member

Claims (16)

  A stacked semiconductor device comprising a plurality of substrates, each of which is stacked at intervals, and a thermal conductive member for improving thermal conductivity between the substrates is disposed between the substrates. A stacked semiconductor device comprising:   The stacked semiconductor device according to claim 1, wherein the heat conductive member is a diamond thin film.   The stacked semiconductor device according to claim 1, wherein the thermally conductive member is a plurality of cylindrical carbon nanotubes.   2. The stacked semiconductor device according to claim 1, wherein the thermally conductive member is a synthetic resin material in which a plurality of cylindrical carbon nanotubes are mixed.   The plurality of carbon nanotubes are arranged so that each axis is directed in a direction perpendicular to the thickness direction of each substrate by a dielectrophoretic force applied to each of the plurality of carbon nanotubes. The stacked semiconductor device described.   2. The stacked semiconductor device according to claim 1, wherein the thermal conductive member is a plurality of granular members in which carbon nanotubes are wrapped with a synthetic resin material having no electrical conductivity.   Each of the substrates and the thermally conductive member disposed between the substrates are formed with through holes that continuously penetrate the substrates and the thermally conductive member in the stacking direction of the substrates, The lamination according to any one of claims 1 to 6, wherein a thermal conductive member for a through hole for improving the thermal conductivity in the through hole is disposed in the through hole. Type semiconductor device.   The stacked semiconductor device according to claim 7, wherein the thermal conductive member for through holes is a plurality of metal particles.   The stacked semiconductor device according to claim 7, wherein the heat conductive member for through holes is a plurality of cylindrical carbon nanotubes.   The multi-layered carbon nanotube according to claim 9, wherein the plurality of carbon nanotubes are arranged in the through holes so that each axis line is directed in an extending direction of the through holes by a dielectrophoretic force applied to each of the carbon nanotubes. Type semiconductor device.   The plurality of carbon nanotubes are arranged in the through-holes so that the respective axes are directed in the extending direction of the through-holes by growing from one end of the through-holes toward the other end. The stacked semiconductor device according to claim 9.   In the stacked semiconductor device including a plurality of stacked substrates, each substrate is formed with a through-hole that continuously penetrates each substrate in the stacking direction. A laminated semiconductor device, wherein a thermal conductive member for improving thermal conductivity in the through hole is disposed.   The stacked semiconductor device according to claim 12, wherein the thermally conductive member is a plurality of metal particles.   The stacked semiconductor device according to claim 12, wherein the thermally conductive member is a plurality of cylindrical carbon nanotubes.   The multi-layered carbon nanotube according to claim 14, wherein the plurality of carbon nanotubes are disposed in the through holes so that each axis is directed in an extending direction of the through holes by a dielectrophoretic force applied to each of the carbon nanotubes. Type semiconductor device.   The plurality of carbon nanotubes are arranged in the through-holes so that the respective axes are directed in the extending direction of the through-holes by growing from one end of the through-holes toward the other end. The stacked semiconductor device according to claim 14.

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