JP2006019595A - Semiconductor device cooling system - Google Patents

Abstract

【Task】
Provided is a cooling device for a semiconductor device that effectively absorbs heat generated by a semiconductor chip and thereby reliably suppresses a temperature rise.
[Solution]
A cooling block having a reflux passage 42 formed by etching the plate-shaped metal material 38 having a thickness of several tens of μm to form the recess 40 and joining the plate-shaped metal material 38 to align the recess 40 therein. 11 is attached so as to overlap or be close to the semiconductor chip 10, and cooling water or a coolant is circulated in the reflux passage 42 to perform forced cooling.
[Selection] Figure 5

Description

  The present invention relates to a cooling device for a semiconductor device, and more particularly to improvement of heat dissipation of a semiconductor integrated circuit (semiconductor element). In particular, the package structure of a semiconductor element capable of forced cooling suitable for use in a CPU or MPU having a large heat generation amount. And its mounting structure.

  A semiconductor device is formed by sealing a semiconductor chip with a synthetic resin or ceramic as an insulating material, and is connected to an external circuit through the electrode portion. The semiconductor element generates heat particularly due to the Joule heat of the current flowing therethrough. Therefore, the temperature rises if the heat dissipation is not performed properly.

  Therefore, for example, in Japanese Patent Laid-Open No. 6-196596, in a semiconductor device in which a semiconductor integrated circuit element and a lead frame connected to the element are sealed with resin to form a sealing resin part, By providing a cooling pipe and flowing air or water through the cooling pipe, a semiconductor device in which heat generated from the semiconductor element is efficiently radiated to the outside through the air or water through the resin sealing portion It is disclosed.

  Japanese Patent Laid-Open No. 2003-297994 discloses a semiconductor chip, a sealing resin portion for sealing the semiconductor chip, and a tab whose back surface opposite to the chip bonding surface to be bonded to the semiconductor chip is exposed on the surface of the sealing portion. And a plurality of inner leads electrically connected to the bonding pads of the semiconductor chip by wires such as gold wires, and a plurality of outer leads that are integrally connected to the inner leads and project outside the sealing portion. Because the entire surface of each of the tab, the plurality of inner leads, and the outer lead is covered with palladium plating, the palladium plating does not melt during solder reflow when the heat dissipation part is attached to the back surface of the tab. Therefore, a semiconductor device that can prevent the heat dissipation member from falling off and thereby improve the reliability is disclosed. There.

  Thus, in order to improve the heat dissipation of the semiconductor device, the surface area of the semiconductor of the sealing resin is increased, a structure in which the heat dissipation plate is in direct contact with the atmosphere, or a structure in which heat dissipation fins are attached to the semiconductor device is employed. I am doing so. Recently, as the integration of semiconductor elements and the increase in power consumption, the amount of heat generation is also increasing along with it, so a method of forced cooling in addition to the above heat dissipation method can be seen in some devices. Became.

  That is, for example, forced air cooling with a fan, use of a heat pipe, use of a Peltier element (Japanese Patent No. 3246199), and the like. In some cases, in order to further improve the effect, cooling of a CPU of a large-sized computer or cooling by a water-cooling method that has been used only for special purposes has come to be performed.

  Thus, when cooling a semiconductor element, it is necessary to devise some kind of device as seen in the conventional example for a semiconductor device that requires heat dissipation. This can be achieved by attaching any device or equipment to the lower or upper surface of the semiconductor device to increase the heat dissipation effect, by natural heat dissipation, forced air cooling, forced liquid cooling, or forced transfer of heat by a Peltier element. It is to be cooled.

Therefore, the size of the semiconductor device is equal to or greater than the thickness of the semiconductor device by attaching such a device or equipment. Therefore, the thickness of the semiconductor device and the cooling device or equipment is taken into account when incorporating it into an electronic device. This is a limitation in the design of electronic devices. Even if a forced air cooling method using a fan having a relatively simple structure is employed, the arrangement of the semiconductor device and the fan is restricted by a structural problem due to a distance problem and an arrangement problem.
JP-A-6-196596 JP 2003-297994 A Japanese Patent No. 3246199

  The subject of this invention is providing the cooling device of the semiconductor device which cools by forcibly taking in the heat which a semiconductor element generate | occur | produces.

  Another object of the present invention is to provide a cooling device for a semiconductor device which has a function of forced cooling without greatly increasing the size of the semiconductor device.

  Another object of the present invention is to provide a semiconductor device that relaxes the limitations imposed by the conventional method, thins the heat dissipation portion, and mounts the semiconductor device at a low cost without departing from the conventional method. Is to provide.

  Still another problem of the present invention is to efficiently dissipate heat from the semiconductor element, and when mounting the semiconductor element, it is possible to keep the thickness of the semiconductor element part almost the same as the conventional one. In comparison, it is an object of the present invention to provide a semiconductor device capable of reducing the number of man-hours and equipment for installing a heat dissipation device.

  The problems of the present invention and other problems will be clarified by the technical idea of the present invention and the embodiments thereof described below.

  The main invention of the present application is to attach a cooling block having a cooling fluid return passage formed therein in contact with or close to the outer surface of a single or a plurality of semiconductor elements, and to return the cooling block through the return passage. The present invention relates to a cooling device for a semiconductor device, wherein the semiconductor element is cooled by a fluid.

  Here, the cooling block is formed by laminating a plurality of grooved plate-like bodies by a diffusion bonding method, and aligning the grooves of the plurality of plate-like bodies to form a reflux path. You may attach so that it may join to the surface on the opposite side to an electrode surface. Further, the cooling block is composed of a combination of at least two plate-like bodies, and a groove for refluxing the cooling fluid is formed on one or both of them, and at least two reflux ports connected to the groove are provided. A connecting means for returning the cooling fluid to the reflux port may be provided. The connecting means may penetrate an interposer substrate on which a semiconductor element is mounted. Further, the connecting means may penetrate a mounting substrate on which the semiconductor device is mounted.

Another main invention of the present application is a semiconductor device in which a semiconductor chip is mounted on a lead frame and sealed with an insulating material.
A cooling block having a cooling fluid return passage formed therein is attached so as to be in contact with or close to the semiconductor chip, and is integrated by the insulating material,
The present invention relates to a cooling device for a semiconductor device, wherein the semiconductor chip is cooled by a fluid returning through a return passage of the cooling block.

  Here, the cooling block may be attached to the lead frame opposite to the semiconductor chip. The cooling block may be attached so as to be sandwiched between the semiconductor chip and the lead frame. The cooling block may have at least two reflux ports communicating with the reflux passage, and the cooling fluid may be refluxed to the reflux passage through the reflux port.

  In the invention as described above, the reflux passage of the cooling block may be changed in shape or size in accordance with heat generated by the semiconductor element to be cooled. The cooling block may be connected to a radiator by a pipe line, and the fluid pumped by the pump may be forcibly circulated. The cooling block constitutes an evaporator, and is connected to a condenser by a pipe line. The fluid compressed by the compressor is liquefied by the condenser, supplied to the evaporator, and repeatedly vaporized while removing heat from the evaporator. It's okay.

  In a preferred embodiment of the present invention, in order to solve the problems of the prior art, the thickness of the member to be used is about 10 to 100 μm (thickness is necessary) so that the thickness of the cooling unit structure of the semiconductor device is not increased. If it is, it is possible to make it thicker.) In forming the reflux path through which the fluid circulates, an etching technique suitable for processing a thin member is adopted. Here, as an etching method, half-etching that etches about half of the base material is frequently used, and the size of the reflux path is made possible by adjusting the opening of the resist mask. In addition, as the most important element for forming the cooling structure of the present invention by laminating the etched members, the adhesive layer, the brazing material, the spot are used between the layers so as not to cause leakage of the cooling fluid from the cooling fluid return path. Adopting a structure that eliminates the risk of leakage by joining the layers by diffusion bonding without relying on welding or the like. Further, as cost considerations, an enlargement of the work size and a multi-layer stacking method are adopted so that a large number of cooling structures can be formed at the same time.

  According to the above aspect, the heat generated by the semiconductor device is thermally transferred to the cooling structure, converted into the cooling fluid flowing inside the cooling structure, and efficiently passed to the outside through the cooling fluid return port. It becomes possible to dissipate heat. Also, in mounting the semiconductor element device, by drilling holes for the inlet and outlet of the cooling fluid return path in the place where the mother board side is mounted in advance, in the height direction of the conventional semiconductor element device Thus, it is possible to perform mounting without greatly deviating from the thickness of the substrate and adding a heat radiation function.

  The main invention of the present application is that a cooling block having a cooling fluid return passage formed therein is attached so as to be in contact with or close to the outer surface of a single or a plurality of semiconductor elements, and the fluid that flows back through the return passage of the cooling block. Thus, the semiconductor element is cooled.

  Therefore, according to such a cooling device for a semiconductor device, the heat generated by the semiconductor chip is forcibly taken away by the fluid flowing back through the tubular passage of the cooling block, and thus the semiconductor chip can be forcibly cooled.

  According to another main invention of the present application, in a semiconductor device in which a semiconductor chip is mounted on a lead frame and sealed with an insulating material, a cooling block having a cooling fluid return passage formed therein is formed in the semiconductor chip. The semiconductor chip is attached so as to be in contact with or close to each other, integrated with an insulating material, and the semiconductor chip is cooled by a fluid that flows back through the return passage of the cooling block.

  Therefore, according to such a cooling device for a semiconductor device, it is possible to forcibly cool the semiconductor chip by taking heat away from the fluid returning through the return passage of the cooling block.

  The present invention will be described below with reference to embodiments shown in the drawings. FIG. 1 shows a semiconductor device according to the present embodiment. This semiconductor device is a semiconductor device called a CSP (chip size package or chip scale package) or BGA (ball grid array). It is.

  The semiconductor chip 10 is fixed to the interposer substrate 12 with Ag paste or the like, and the electrode pad 16 of the semiconductor chip 10 and the electrode 18 of the interposer substrate 12 are connected by a metal wire 17 such as Au or Al. 17 is formed by printing or molding. The cooling block 11 is sandwiched between the semiconductor chip 10 and the interposer substrate 12.

  The interposer substrate 12 is usually composed of a multilayer substrate formed by laminating an organic material of a thermosetting resin such as an epoxy resin or a polyimide resin and a copper foil, or a multilayer structure of about 4 to 8 layers made of a material such as glass or ceramic. Consists of a substrate. The interposer substrate 12 is a package such as CSP or BGA, and is an intermediate substrate on which the semiconductor chip 10 is mounted in order to perform matching between the semiconductor chip 10 and the terminal for connecting the printed wiring board 21 or grid conversion.

  The interposer substrate 12 is formed with a bump substrate 22 in accordance with the arrangement of the bump electrodes 23 formed on the mother board 21, and these are connected by a spherical bump 24, and the mother board 21 and the interposer substrate 12 are connected to each other. Connected. In FIG. 1, a semiconductor chip 10 is attached to a cooling block 11 and is different from a normal CSP or BGA structure.

  The cooling block 11 is formed by the manufacturing method shown in FIGS. 3 and 4 to be described later, and is connected as shown in the system diagram of FIG. 7 to exert its effect. In FIG. 1, a conductive or non-conductive paste such as an Ag paste is used for the cooling block 11 in the semiconductor chip 10, these pastes are applied to the bonding surface of the semiconductor chip 10 and the cooling block 11, and then cured and cooled. The block 11 is fixed in the same manner as the interposer substrate 12.

  The cooling block 11 includes at least two reflux ports 27, penetrates the interposer substrate 12, is connected to the cylindrical connector 28, and is fastened. The interposer substrate 12 and the mother board 21 need to be drilled in advance for passing through the reflux port 27 and the cylindrical connector 28, respectively. A pipe line is connected to the tubular connector 28, one of the reflux ports is connected to the pump 48, and the exhaust port 27 on the exhaust heat side is connected to the radiator 52 (see FIG. 7).

  The cooling block 11 is formed by a manufacturing method and a material to be described later, and a material having extremely high thermal conductivity is selected and used, and a hollow reflux passage 42 through which a cooling fluid can circulate inside the structure is formed. ing. Note that a material having high thermal conductivity is also used for the Ag paste.

  Heat generated from the semiconductor chip 10 as a heating element is transferred through the following path, thereby suppressing a temperature rise of the semiconductor chip 10. That is, the semiconductor chip 10 is forcibly cooled by transferring heat in the order of the semiconductor chip 10, Ag paste (bonding between 10-11), the cooling block 11, and the radiator 52.

  FIG. 2 shows an example of a semiconductor package called CSP or BGA as in FIG. 1, but the semiconductor chip 10 is connected by bumps 33 formed on the semiconductor chip 10 side or the interposer substrate 12 side without wire bonding. The modification of a form is shown. This modification is generally called a flip-chip type CSP or BGA.

  The semiconductor element 10 is circuit-connected to the interposer substrate 12 by bumps 33. Here, the bumps 33 are solder balls, a method by plating of Au, Ui, etc. It is formed by a method of connecting and cutting with a necessary dimension and hitting the upper part to make the height uniform.

  As a connection method, in the case of solder, cream solder is applied to the electrode 18 side of the interposer substrate 12, and the element 10 including the bumps 33 is mounted thereon and melt-bonded through a reflow apparatus. . The Ni bump is the same method. When the bump material is Au, the connection is established by ultrasonic bonding or thermocompression bonding with an ACF (anisotropic conductive film) sandwiched between the bump 33 and the electrode 16. ACF (anisotropic conductive film) is usually sheet-like, but paste-like is also present.

  When the bump 33 is solder, the underfill resin 32 is injected between the electrode 16 of the semiconductor chip 10 and the electrode 18 of the interposer substrate 12 through a cleaning process until the connection is completed. When using ACF (anisotropic conductive film) or anisotropic conductive paste, the underfill resin 32 is not required.

  In FIG. 2, the cooling block 11 is fixed to the back surface (upper surface) of the semiconductor chip 10 with a material having extremely high conductivity such as Ag paste as in FIG. In FIG. 2, the underfill resin 32 is at a position lower than the height of the semiconductor chip 10 and the spread of the underfill resin 32 is substantially the same as the size of the semiconductor chip 10.

  This is because the strength of the connection surface between the semiconductor chip 10 and the interposer substrate 12 is expected to be insufficient. Therefore, when any impact is applied, the connection between the semiconductor chip 10 and the interposer substrate 12 is performed. There is concern about defects. In order to cover this, fixing by the presser fitting 34 is employed. The holding metal fitting 34 is provided with a countermeasure such as fixing to the reflux port 27 formed in the cooling block 11 with screws, and is fixed to the peripheral portion of the interposer substrate 12 by soldering or by means such as screwing. Strength can be increased.

  Although the structure shown in FIG. 2 seems to be not much different from the conventional system, the heat dissipation structure is made as thin as possible and is fastened to the semiconductor chip 10 by the best material and connection method. Mounting is simplified, and the mounting in the height direction can be minimized.

  Next, the configuration of the cooling block 11 attached to be joined to the semiconductor chip 10 will be described with reference to FIGS. First, the feature of the manufacturing method of the cooling block 11 is that it is assembled by using diffusion bonding.

  In diffusion bonding, when two members are pressurized and heated, mutual diffusion of atoms occurs at the bonded portion, and the two members are bonded. A bonding method using this action is diffusion bonding. Diffusion bonding includes solid phase diffusion bonding and liquid phase diffusion bonding, but solid phase diffusion bonding is a method of bonding without melting, and liquid phase diffusion bonding uses an insert material between the materials to be bonded, In this method, the base material is melted between the joints. The atmosphere is mainly performed in a vacuum, but it may also be performed with an inert gas (for example, argon gas).

  The temperature of diffusion bonding varies depending on the material used, but generally it is often 1000 ° C. or higher. When diffusion bonding is performed on the same kind of metal, no reaction occurs in the bonded portion, and a uniform bonded interface is obtained. This means that a joining interface is not substantially generated. In the case of dissimilar bonding materials, a bonding interface is formed.

  In general, diffusion bonding is characterized by thin plate surface bonding, multiple thin plate lamination bonding, metal bonding that is difficult to melt, and dissimilar material bonding, assembly accuracy Is relatively high, complex and capable of joining hollow parts.

As materials that can be joined by diffusion bonding, Ni-based materials, iron-based materials, copper-based materials, aluminum-based materials, titanium-based materials, ceramic-based materials, copper materials, and other materials can be combined. Specific materials are selected from a wide range of materials such as stainless steel (SUS304, SUS316, etc.), nickel and nickel alloys (42FN, 50FN, etc.), titanium, Cu (oxygen-free Cu, pure copper), aluminum, Al ₂ O _{3 and the} like. It is possible.

  The work size at the time of lamination depends on the specifications of the press machine, but is still about 500 × 500 mm. The above is an outline of diffusion bonding, but the cleanness and surface condition of the bonding surface greatly affect the bonding quality.

  As the material 38 in step 1 of FIG. 3, a material capable of diffusion bonding as described above is selected. In the present embodiment, SUS, Ni alloy, or Cu material is used. The thickness of the material 38 can be selected from materials having a minimum thickness of 20 μm. The work size is obtained by applying the same kind of multiple pieces to the required solid.

  Such a plate-shaped metal material 38 covers a predetermined portion with a mask 39 before being put into the etching step (step 1). Here, a resin resist material is used. In the drawing, the illustration of the resist on the back side is omitted, but the resist is applied to the entire back side. In addition, the resist opening at the location to be etched is formed by selecting a photosensitive photo resist and washing the portion corresponding to the portion to be etched by exposure.

  Step 2 is an etching step. That is, the etching portion 40 is half-etched while leaving the portion where the mask 39 is applied in the step 1. In etching, a predetermined etching rate can be obtained by controlling the concentration of the etching solution and the immersion time. Therefore, when the material 38 is pulled up after a predetermined time has elapsed, about half of the thickness of the material is reduced. It will be etched.

  Thereafter, in step 3, the resist 39 is peeled off. Then, in step 4, the material 38 is laminated and bonded. The material 38 having undergone the above steps 1 to 3 is bonded by diffusion bonding. The recess 40 formed by half-etching is a portion that becomes the reflux passage 42 of the cooling body after lamination. The recesses 40 formed in the respective materials 38 are arranged so as to face each other and are aligned to form the pipe line 42.

  Thereafter, machining such as drilling or additional machining of the material 38 bonded by diffusion bonding is performed, and the reflux port 27 is processed or attached, or separated into individual pieces. Separation from the workpiece size into each solid piece is performed by a punching die, a dicer or the like.

  FIG. 4 shows an example of a pattern for forming the reflux passage 42 of the cooling block 12. The reflux path 42 is not limited to a simple pattern as shown in FIG. 4, and can be set in any way on the CAD such as the size or path of the pattern. The CAD system to be used is an apparatus used for a printed circuit board. Can be diverted. It is preferable to form reflux ports 27 at both ends of the pattern.

  The pattern is engraved by opening the resist 39 in the pattern portion and eroding this portion into the etching solution by baking this pattern on the surface of the photosensitive resin to the same size as the base material 38 to be etched. It is. Although the pattern shape shown in FIG. 4 is a simple pattern, it is possible to form an etching pattern on each layer or to form a reflux path 42 between layers by a drilling instruction by the same method as that of the printed wiring board.

  FIG. 5 shows the structure of the cooling block 11 in the embodiment of the present invention. The cooling block 11 is formed on the basis of the manufacturing method shown in FIGS. 3 and 4. In FIG. 5, two materials 38 are joined so that the recesses 40 communicate with each other. A passage 42 is formed.

  The configuration shown in FIG. 6 shows a configuration in which the same or different materials 38 are laminated in five layers, thereby forming the reflux passage 42 in two layers. In FIG. 6, the attachment hole 45 is formed by drilling after joining the material 38. Such an attachment hole 45 can be used for fastening with the interposer substrate 12 or for coupling the cooling block 11 and the semiconductor chip 10. The attachment hole 45 is not necessarily required.

  In the cooling block 11 shown in FIG. 5 or FIG. 6, when the cooling fluid is returned to the return passage 42 in the cooling block 11, the problem of fluid leakage is most concerned. Measures are taken such as adding a sealing material such as paint or seal to the threaded portion and attaching it to the processed threaded portion of the cooling structure, or sealing with a brazing material after mounting with a screw or the like.

  Such a cooling block 11 and an external device are connected to the pump 48 and the radiator 52 through a pipe line as shown in FIG. 7, but here, they are connected using a relatively flexible tube made of silicon resin or the like. can do. Even in this case, it is necessary to take measures against liquid leakage at the connection portion with the tube.

  Next, the operation of the semiconductor device cooling apparatus as described above will be described. The cooling block 11 as shown in FIG. 5 or FIG. 6 is attached to the lower surface of the semiconductor chip 10 as shown in FIG. 1 or attached to the upper surface of the semiconductor chip 10 as shown in FIG. Will be described with reference to FIG. As described above, the suction-side reflux port 27 of the pair of reflux ports 27 of the cooling block 11 is connected to the pump 48, and the discharge-side reflux port 27 is connected to the radiator 52. The pump 48 is driven by a motor 49 and a drive circuit 50. A drive circuit 50 for driving the motor 49 is connected to the temperature sensor 51. On the other hand, the radiator 52 includes the radiation fins 53 and the cooling air is forced to be blown from the cooling fans 54 to the radiation fins 53. The cooling fan 54 is driven by a motor 55 and a drive circuit 56.

  Therefore, when the pump 48 is driven by the motor 49, a cooling fluid, for example, water circulates in the closed pipe line composed of the pump 48, the cooling block 11, and the radiator 52, and particularly when passing through the reflux passage 42 of the cooling block 11. The heat generated by the chip 10 is taken away. And the cooling water heated by this is forcibly pumped to the radiator 52, and here, heat is released by the radiation fins 53 to be in a low temperature state. Then, the low-temperature water is forcibly circulated to the cooling block 11 by the pump 48 again. By repeating such circulation, the heat of the semiconductor chip 10 is surely removed.

  FIG. 8 shows a configuration using a refrigeration cycle as a cycle for cooling. That is, here, a compressor 60 is used in place of the pump 48, and the compressor 60 is driven by an actuator 61 made of, for example, a piezoelectric element. A condenser 62 is connected to the reflux port 27 on the opposite side of the cooling block 11, and an expansion valve 63 is connected between the condenser 62 and the cooling block 11.

  In such a configuration, ammonia or alternative chlorofluorocarbon is used as the cooling medium. Accordingly, here, the cooling block 11 acts as an evaporator, and the refrigerant is evaporated by the heat generated by the semiconductor chip 10. The vaporized refrigerant is compressed by the compressor 60 and supplied to the condenser 62, where heat is released and the liquid is condensed and liquefied. The liquefied refrigerant is repeatedly circulated through the expansion valve 63 to return to the cooling block 11. That is, here, the cooling block 11 and the capacitor 61 take away the heat of the semiconductor chip 10 while the cooling medium changes phase between liquid and gas.

  Next, another embodiment will be described with reference to FIGS. This embodiment is an embodiment in which the present invention is applied to a lead frame type semiconductor device, and is a device for cooling a semiconductor chip 10 molded with an insulating resin on a holding portion 73 of a lead frame 72. is there.

  Regardless of the surface mounting type or the dip type, the package form of the widely used semiconductor device is formed by fixing the semiconductor chip 10 to the lead frame 72 and molding it, and bending the lead 75 to be soldered to the motherboard. A shape cut from the lead frame 72 is employed.

  The present embodiment provides a form in which a cooling structure is attached without departing from the package form of this type of semiconductor element that has been widely used. First, the lead frame 72 is usually a metal material mainly composed of 42FN, 50FN, copal, etc., and is a material frequently used for the semiconductor lead frame 72. Such a lead frame 72 is a band-shaped material provided with guide holes 78 on both side ends, and is used for mounting the semiconductor chip 10 at a predetermined position, or for confirming the position for applying Ag paste or the like. It is done.

  After the semiconductor chip 10 is mounted on the holding portion 73 of the lead frame 72 and molded with resin, it is cut at the cutting line 76 with a mold. The lead 75 generated by such cutting is soldered and mounted on a mother board or the like. The lead 75 is bent at a bending line 77 at the base side of the cutting line 76. That is, in such a semiconductor device, the lead 75 is bent and mounted on a printed board. In particular, the semiconductor chip 10 is mounted on the holding portion 73 of the lead frame 72 and is covered with a mold resin.

  Here, as shown in FIG. 10, the semiconductor chip 10 mounted on the holding portion 73 of the lead frame 72 is on the opposite surface or between the semiconductor chip 10 and the lead frame 72 as shown in FIG. The cooling block 11 is attached.

  As a method for attaching the cooling block 11, there is a method using Ag paste, brazing, welding or the like. In the case of the configuration of FIG. 10, the heat generated from the semiconductor element 10 is transmitted to the lead frame 72 via the Ag paste of the adhesive layer between the semiconductor element 10 and the lead frame 72, and the opposite surface Is transmitted to the cooling block 11 attached to the. Here, as in the first embodiment, the cooling block 11 circulates in the reflux passage 42 in the cooling block 11, so that heat is exchanged with the cooling body via the cooling block 11. For example, the cooling fluid is forcibly circulated by the pressure of the pump 48 shown in FIG. 7 or the pressure of the compressor 60 shown in FIG.

  In the configuration shown in FIG. 10, the cooling block 11 is disposed on the side opposite to the semiconductor chip 10 with respect to the lead frame 72, but may be mounted on the mounting surface side of the semiconductor chip 10 as shown in FIG. 11. The reflux port 27 is attached directly from the cooling block 11 or through the lead frame 12. In the case of the configuration of FIG. 11, it is necessary to form an opening at a position where the reflux port 27 is formed in the lead frame 72.

  The electrodes of the semiconductor chip 10 are connected to corresponding terminal portions of the leads 75 of the lead frame 72 shown in FIG. 9 by wire bonding. Thereafter, molding resin molding is performed, the lead 75 is cut at the cutting line 76, and the bending process is performed along the folding line 77. At the time of molding, a predetermined measure is taken to prevent the mold resin from adhering to the reflux port 27 and closing the mold.

  As shown in FIG. 10 or FIG. 11, the cooling block 11 attached together with the semiconductor chip 10 on the lead frame 72 is connected to, for example, the pump 48 and the radiator 51 shown in FIG. That is, the cooling block 11 is provided with at least two reflux ports 27, and one of these reflux ports 27 is connected to the pump 48, and the cooling water always cooled by this is sucked into the cooling block 11. On the other hand, the discharge-side reflux port 27 exchanges heat so as to extrude the fluid pumped by the pump 48, discharges this cooling water from the reflux port 27, and pushes it to the radiator 52. The radiator 52 is provided with cooling means such as radiating fins 53 and fans 54 that are forcibly cooled in order to lower the cooling body to a normal temperature.

  The pump 48 operates in conjunction with a temperature sensor 51 provided on the semiconductor chip 10 or the cooling block 11 that is a heating element or a timer from power ON, and when the drive circuit 50 is driven, the pump 48 is driven via the motor 49 thereby. Work to circulate. Of course, the radiator 52 also has a control circuit for driving a necessary cooling device by the output of the previous sensor 51 or a timer or the like.

  Here, as the cooling fluid, it is possible to use a fluid constituting water or other cooling fluid, air or other gas for this cooling system. When a refrigeration cycle as shown in FIG. 8 is used, a low boiling point refrigerant such as ammonia or chlorofluorocarbon is used.

  The biggest problem in such a forced cooling system is the leakage of liquid at the cooling block 11 and its piping part, and corrosion of the pipe line. In the present embodiment, the material of the cooling block 11 is made of stainless steel or a material having high corrosion resistance, and diffusion that does not generate a joint or a gap due to an adhesive or spot welding in the connection between layers. Connection is performed using a joining method.

  Further, the reflux port 27 of the cooling block 11 is brazed to the cooling block 11 so that there is no fear of liquid leakage, and sufficient consideration is given to the attachment of a pipe serving as a reflux path. The sensor that detects the temperature of the semiconductor chip 10 or the cooling block 11 senses the temperature of the heating element, and therefore, for example, a thermistor or a thermocouple is used.

  Although the present invention has been described above with reference to the illustrated embodiments, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the technical idea of the invention included in the present application. For example, in the above embodiment, the specific pattern of the reflux passage 42 of the cooling block 11 that cools the semiconductor chip 10, the mounting structure for the semiconductor chip 10, and the like are various designs corresponding to the shape of the semiconductor chip 10. It can be changed. In addition, a single cooling block 11 may be attached to a plurality of semiconductor chips 10 in common.

  The present invention can be widely used for cooling a semiconductor device including a semiconductor element such as a CPU or MPU whose temperature is likely to rise.

It is a longitudinal cross-sectional view of a semiconductor device provided with a cooling block. It is a longitudinal cross-sectional view of the modification of a semiconductor device provided with a cooling block. It is a longitudinal cross-sectional view which shows the etching process of the plate-shaped body which comprises a cooling block. It is a top view of the plate-shaped metal material which performed the etching process. It is a longitudinal cross-sectional view of a cooling block. It is a longitudinal cross-sectional view of the cooling block of a modification. It is a piping diagram which shows the connection of a cooling device. It is a piping diagram of the cooling device concerning a modification. It is a top view of the lead frame of another embodiment. It is a longitudinal cross-sectional view of the semiconductor device using a lead frame. It is a longitudinal cross-sectional view of the semiconductor device using the lead frame concerning a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Semiconductor chip, 11 ... Cooling block, 12 ... Interposer board, 13 ... Mold resin, 16 ... Electrode pad, 17 ... Connection wire, 18 ... Electrode pad, 21 ... Mother board (mounting board) , 22, 23 ... Bump electrode, 24 ... Bump, 27 ... Return port, 28 ... Cylindrical connector, 32 ... Underfill resin, 33 ... Bump, 34 ... Press fitting, 38 ... Plate Metallic material, 39 ... Mask, 40 ... Etching part (concave part), 42 ... Recirculation passage, 45 ... Mounting hole, 48 ... Pump, 49 ... Motor, 50 ... Drive circuit, 51 ... Temperature Sensor, 52 ... Radiator, 53 ... Radiating fin, 54 ... Cooling fan, 55 ... Motor, 56 ... Drive circuit, 60 ... Compressor, 61 ... Actuator, 62 ... Capacitor, 63 ... Expansion Valve, 72 ‥‥ lead frame, 73 ‥‥ holding portion, 74 ‥‥ connecting portion, 75 ‥‥ lead, 76 ‥‥ cutting line, 77 ‥‥ fold lines, 78 ‥‥ guide hole

Claims (12)

  A cooling block having a cooling fluid return passage formed therein is attached so as to be in contact with or close to the outer surface of one or a plurality of semiconductor elements, and the semiconductor element is cooled by the fluid flowing back through the return passage of the cooling block. A cooling device for a semiconductor device.   The cooling block is formed by laminating a plurality of grooved plate-like bodies by a diffusion bonding method, and aligning the grooves of the plurality of plate-like bodies to form a reflux path, and forming an electrode surface of a semiconductor element 2. The cooling device for a semiconductor device according to claim 1, wherein the cooling device is attached so as to be bonded to a surface opposite to the semiconductor device.   The cooling block is composed of a combination of at least two plate-like bodies, and a groove for refluxing the cooling fluid is formed on one or both of them and bonded, and at least two reflux ports connected to the groove are provided. 2. The cooling device for a semiconductor device according to claim 1, further comprising a connecting means for returning a cooling fluid to the reflux port.   4. The cooling device for a semiconductor device according to claim 3, wherein the connecting means passes through an interposer substrate on which a semiconductor element is mounted.   4. The semiconductor device cooling apparatus according to claim 3, wherein the connecting means penetrates a mounting substrate on which the semiconductor device is mounted. In a semiconductor device in which a semiconductor chip is mounted on a lead frame and sealed with an insulating material,
A cooling block having a cooling fluid return passage formed therein is attached so as to be in contact with or close to the semiconductor chip, and is integrated by the insulating material,
A semiconductor device cooling apparatus, wherein the semiconductor chip is cooled by a fluid that flows back through a reflux passage of the cooling block.   The semiconductor device cooling device according to claim 6, wherein the cooling block is attached to the lead frame opposite to the semiconductor chip.   The semiconductor device cooling apparatus according to claim 6, wherein the cooling block is attached so as to be sandwiched between the semiconductor chip and the lead frame.   The cooling device for a semiconductor device according to claim 6, wherein the cooling block has at least two reflux ports communicating with the reflux passage, and the cooling fluid is refluxed to the reflux passage through the reflux port.   The cooling device for a semiconductor device according to claim 1, wherein a shape or a dimension of the reflux passage of the cooling block is changed according to heat generated by a semiconductor element to be cooled.   The cooling device for a semiconductor device according to claim 1, wherein the cooling block is connected to a radiator by a pipe line, and the fluid pumped by the pump is forcibly circulated. The cooling block constitutes an evaporator, is connected to a condenser by a pipe line, and fluid that is pumped by a compressor is liquefied by the condenser and supplied to the evaporator, and the evaporator is repeatedly vaporized while removing heat. The semiconductor device cooling device according to claim 1, wherein the cooling device is a semiconductor device cooling device.

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