Method of manufacturing semiconductor device and semiconductor device

Abstract

To provide a method of manufacturing a semiconductor device and the semiconductor device, which can alleviate the influence of warpage of a semiconductor module without using another material for suppressing the warpage of the semiconductor module.SOLUTION: The method of manufacturing a semiconductor device includes the following steps. The semiconductor module 101, the solder bonding material 5, and the heat dissipation member 6 are heated in a state in which the semiconductor module 101, in which the semiconductor element 2 is mounted on the substrate 4 by the bonding member 3 and the semiconductor element 2, the bonding member 3, and the substrate 4 are sealed with the sealing resin 1, is placed on the heat dissipation member 6 via the solder bonding material 5. After the semiconductor module 101, the solder bonding material 5, and the heat dissipation member 6 are heated, the semiconductor module 101 is cooled by the semiconductor module cooling source 1001, and the solder bonding material 5 is solidified later than the sealing resin 1.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a semiconductor device and a semiconductor device. [Background technology]

[0002] Traditionally, semiconductor devices have typically mounted resin-encapsulated semiconductor modules on heat dissipation components using grease or other adhesives. However, an increasing number of semiconductor devices have been solder-bonded to heat dissipation components to improve heat dissipation. When mounting a conventional semiconductor module on a heat dissipation component using grease or other adhesives, the grease easily follows the warpage of the semiconductor module, eliminating the need for warping. However, when a semiconductor module is solder-bonded to a heat dissipation component, solder solidifies at temperatures above 200°C, creating a problem: the solder cannot easily adapt to changes in the warpage of the semiconductor module during cooling. As a result, the solder joint layer experiences significant stress during and after solder solidification, causing the semiconductor module substrate to warp. This leads to cracks in the solder joint layer after cooling or during temperature cycles following cooling. Resins have a glass transition temperature, and their linear expansion coefficient increases above that temperature. This further increases the difference in linear expansion coefficient between the solder joint layer and the semiconductor module substrate. If the resin is above its glass transition temperature during or after solder solidification, the stress on the solder joint layer increases.

[0003] Furthermore, when joining a resin-encapsulated semiconductor module to a heat dissipation component, the upper limit of the process temperature during soldering is set to prevent the joining materials inside the resin-encapsulated semiconductor module from melting, which limits the solder composition that can be used for the solder joining material. For example, adding bismuth (Bi) or indium (In) can lower the melting point of the solder, thereby allowing the process temperature to be lowered. However, the addition of bismuth (Bi) or indium (In) reduces the ductility of the solder joining material, making it more susceptible to cracks developing in the solder joining material due to warping of the semiconductor module.

[0004] With the structural changes in semiconductor devices as described above, there is an increasing need to alleviate the stress on solder joint materials caused by warpage of semiconductor modules. To address this issue, for example, Japanese Patent Laid-Open Publication No. 2002-198396 (Patent Document 1) describes a method for manufacturing a semiconductor device in which a resin-encapsulated semiconductor module is fixed with a resin adhesive to suppress warpage of the semiconductor module. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-198396 Summary of the Invention [Problem to be solved by the invention]

[0006] In the semiconductor device manufacturing method described in the above publication, a resin adhesive (thermosetting resin material) is applied to a dedicated application area to prevent warpage of the semiconductor module. Using a separate material (thermosetting resin material) to prevent warpage of the semiconductor module in this way increases product costs due to the addition of a separate material, an additional supply process, and an increase in product area due to the area to which it is supplied (the dedicated application area). Furthermore, there is a possibility that the fixing portion (the portion where the thermosetting resin material is fixed to the dedicated application area) may peel off due to impact or thermal cycles during product use, making it impossible to prevent warpage of the semiconductor module.

[0007] The present disclosure has been made in consideration of the above-mentioned problems, and its purpose is to provide a semiconductor device and a manufacturing method thereof that can mitigate the effects of warping of a semiconductor module without using a separate material to suppress warping of the semiconductor module. [Means for solving the problem]

[0008] The method for manufacturing a semiconductor device according to the present disclosure includes the following steps: a semiconductor element is mounted on a substrate with a bonding material, and a semiconductor module, in which the semiconductor element, bonding material, and substrate are sealed with a sealing resin, is placed on a heat dissipation member via a solder bonding material, and the semiconductor module, solder bonding material, and heat dissipation member are heated. After the semiconductor module, solder bonding material, and heat dissipation member are heated, the semiconductor module is cooled by a semiconductor module cooling source, and the solder bonding material solidifies later than the sealing resin. [Effects of the Invention]

[0009] According to the method for manufacturing a semiconductor device of the present disclosure, it is possible to mitigate the effects of warpage of the semiconductor module without using a separate material for suppressing warpage of the semiconductor module. [Brief explanation of the drawings]

[0010] [Figure 1] 3 is a cross-sectional view schematically showing a soldering heating step in the method for manufacturing the semiconductor device according to the first embodiment. FIG. [Figure 2] 4 is a cross-sectional view schematically showing a soldering cooling step in the method for manufacturing the semiconductor device according to the first embodiment. FIG. [Figure 3] 4 is a cross-sectional view schematically showing a state in which a heat dissipation member is heated by a heat dissipation member heating source in a soldering cooling step of the manufacturing method of the semiconductor device according to the first embodiment. FIG. [Figure 4] 10 is a cross-sectional view schematically showing a state in which a shape for increasing the surface area is provided in the sealing resin in a soldering and cooling step of the manufacturing method of the semiconductor device according to the first embodiment. FIG. [Figure 5] 1 is a cross-sectional view schematically showing a configuration of a semiconductor device according to a first embodiment. [Figure 6] 10 is a cross-sectional view schematically showing a soldering cooling step in a manufacturing method of a semiconductor device according to a second embodiment. FIG. [Figure 7] 10 is a cross-sectional view schematically showing a state in which the heat insulating material is integrated with the air blow cover in a soldering cooling step of the manufacturing method of the semiconductor device according to the second embodiment. FIG. [Figure 8]10 is a cross-sectional view schematically showing a state in which air blown from a semiconductor module cooling source flows from a side surface in a soldering cooling step of a manufacturing method for a semiconductor device according to a second embodiment. FIG. [Figure 9] 10 is a cross-sectional view schematically showing a case where the heat dissipation component has a large heat capacity in a soldering cooling step of a manufacturing method for a semiconductor device according to a second embodiment. FIG. [Figure 10] FIG. 10 is a cross-sectional view for explaining the mechanism by which shrinkage cavities occur in a solder joint material. [Figure 11] FIG. 11 is a cross-sectional view taken along line XI-XI in FIG. [Figure 12] 11 is a cross-sectional view schematically showing a soldering cooling step in a manufacturing method of a semiconductor device according to a third embodiment. FIG. [Figure 13] FIG. 11 is a plan view schematically showing a soldering cooling step in the method for manufacturing a semiconductor device according to the third embodiment. [Figure 14] FIG. 11 is a cross-sectional view schematically showing a soldering cooling step in a modified example of the method for manufacturing a semiconductor device according to the third embodiment. [Figure 15] FIG. 11 is a plan view schematically showing a soldering cooling step in a modified example of the method for manufacturing a semiconductor device according to the third embodiment. [Figure 16] FIG. 10 is a cross-sectional view schematically showing a heat dissipation member cooling step in a manufacturing method for a semiconductor device according to a fourth embodiment. [Figure 17] FIG. 10 is a cross-sectional view schematically showing a state in which fins are provided on the heat dissipation member in a heat dissipation member cooling step in the manufacturing method of a semiconductor device according to the fourth embodiment. [Figure 18] FIG. 11 is a cross-sectional view schematically showing a state in which a plurality of air blow inlets are provided in a heat dissipation member cooling step of a manufacturing method for a semiconductor device according to a fourth embodiment. [Figure 19] FIG. 10 is a cross-sectional view schematically showing a state in which the air blow inlet is positioned offset toward the outer periphery of the solder joint material in the heat dissipation member cooling step of the manufacturing method for a semiconductor device according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments will be described with reference to the drawings. In the following, the same or corresponding parts will be denoted by the same reference numerals, and overlapping descriptions will not be repeated.

[0012] Embodiment 1 A method for manufacturing a semiconductor device according to a first embodiment will be described with reference to Figures 1 to 4. Figure 1 is a cross-sectional view schematically showing a soldering heating step in the method for manufacturing a semiconductor device according to the first embodiment. Figure 2 is a cross-sectional view schematically showing a soldering cooling step in the method for manufacturing a semiconductor device according to the first embodiment. Figure 3 is a cross-sectional view schematically showing how a heat dissipation member is heated by a heat dissipation member heating source in the soldering cooling step in the method for manufacturing a semiconductor device according to the first embodiment.

[0013] The method for manufacturing a semiconductor device according to the first embodiment includes a soldering heating step and a soldering cooling step.

[0014] 1, in a soldering heating process, in a semiconductor module 101, a semiconductor element 2 is mounted on a substrate 4 by a bonding member 3. A sealing resin 1 covers and seals the mounted components such as the semiconductor element 2 and the bonding member 3 mounted on the substrate 4. At least a part of the surface of the substrate 4 opposite the semiconductor element mounting surface is not sealed with the sealing resin 1 and is exposed from the sealing resin 1. The exposed surface of the substrate 4 of the semiconductor module 101 is joined to a heat dissipation member 6 via a solder bonding material 5.

[0015] In the soldering heating process, the semiconductor device 102 is heated from the periphery of the semiconductor device 102 by a semiconductor device heating source 1000. The semiconductor element 2 is mounted on the substrate 4 by the bonding member 3, and the semiconductor module 101, in which the semiconductor element 2, the bonding member 3, and the substrate 4 are sealed with the sealing resin 1, is placed on the heat dissipation member 6 via the solder bonding material 5, and the semiconductor module 101, the solder bonding material 5, and the heat dissipation member 6 are heated.

[0016] 2, in the soldering cooling process, the semiconductor device 102 is cooled from the semiconductor module 101 side by a semiconductor module cooling source 1001. After the semiconductor module 101, the solder joint material 5, and the heat dissipation member 6 are heated, the semiconductor module 101 is cooled by the semiconductor module cooling source 1001, and the solder joint material 5 is solidified later than the sealing resin 1.

[0017] 3, in the soldering cooling step, the semiconductor device 102 may be heated from the heat dissipation member 6 side by a heat dissipation member heating source 1002. The semiconductor module 101 is cooled by the semiconductor module cooling source 1001, and the heat dissipation member 6 is heated by the heat dissipation member heating source 1002.

[0018] The solder joint material 5 is made of a material in which one or more of silver (Ag), copper (Cu), bismuth (Bi), indium (In), antimony (Sb), zinc (Zn), cadmium (Cd), gold (Au), aluminum (Al), arsenic (As), iron (Fe), and nickel (Ni) are added to tin (Sn). In particular, when the melting point of the solder joint material 5 is to be lowered to prevent the joint material inside the semiconductor module 101 from melting, it is desirable that one or more of bismuth (Bi), indium (In), and zinc (Zn) be added to the solder joint material 5.

[0019] Furthermore, epoxy resins and the like are used for the sealing resin 1. However, in the case of resins with a glass transition temperature, the sealing resin 1 has a large linear expansion coefficient at temperatures higher than the glass transition temperature, and the difference in linear expansion coefficient between the sealing resin 1 and the substrate 4 is large, resulting in a large amount of warpage change per unit temperature. It is desirable that the solder joint material 5 falls below its liquidus temperature after the sealing resin 1 drops below its glass transition temperature. It is even more desirable that the solder joint material 5 falls below its solidus temperature after the sealing resin 1 drops below its glass transition temperature. This reduces the amount of warpage change of the semiconductor module 101 after the solder joint material 5 solidifies. To achieve this temperature profile, it is desirable that the glass transition temperature of the sealing resin 1 is higher than the solidus temperature of the solder joint material 5.

[0020] It is more desirable that the glass transition temperature of the sealing resin 1 be higher than the liquidus temperature of the solder joint material 5. Between the liquidus temperature and solidus temperature of the solder joint material 5, the solder joint material 5 is in a mixed liquid and solid phase. Unlike in the solid state, the solder joint material 5 is deformable, but is less deformable than in the liquid state. In this state, if the sealing resin 1 is at a temperature above its glass transition temperature and the semiconductor module 101 warps significantly, the solder joint material 5 may not be able to keep up with the warpage of the semiconductor module 101, potentially resulting in portions of the semiconductor module 101 separating from the solder joint material 5. Having the glass transition temperature of the sealing resin 1 higher than the liquidus temperature of the solder joint material 5 prevents deformation of the semiconductor module 101 even between the liquidus temperature and solidus temperature of the solder joint material 5. This prevents peeling between the semiconductor module 101 and the solder joint material 5.

[0021] Furthermore, it is desirable that the melting point of the joining member 3 is higher than the liquidus temperature of the solder joining material 5. Even if the temperature is raised above the liquidus temperature of the solder joining material 5 in the joining process of the solder joining material 5, the joining member 3 does not melt, and therefore cracking of the sealing resin 1 due to volume expansion during melting can be suppressed.

[0022] The semiconductor module cooling source 1001 may be a means for cooling by heat transfer through contact with metal or resin, or a means for cooling by forced convection through blowing air. A means for cooling by heat transfer is effective in a configuration that does not involve such concerns, since a force applied to the solder joint material 5 through the semiconductor module 101 may cause the solder joint material 5 to be expelled from directly below the semiconductor module 101. Furthermore, in a means for cooling by forced convection through blowing air, a shape 1a that increases the surface area, such as a fin shape, may be provided on the semiconductor module cooling source 1001 side of the sealing resin 1, as shown in FIG. 4, in order to increase the cooling efficiency of the semiconductor module 101. The shape 1a does not have to be the shape shown in FIG. 4; any shape that can increase the surface area will provide a similar effect.

[0023] The heat dissipation member heating source 1002 may be a means for heating by heat transfer by contacting a metal or resin plate with a built-in heater, or a means for heating by forced convection by blowing air heated by a separate heating source. Heating the heat dissipation member 6 by blowing heated air is particularly effective when the heat dissipation member 6 has irregularities such as fins on the heat dissipation member heating source 1002 side. The temperature of the heat dissipation member heating source 1002 is preferably equal to or higher than the solidus temperature of the solder joint material 5, but even if the temperature is lower than the solidus temperature, it can be effective because a decrease in the temperature of the solder joint material 5 can be suppressed.

[0024] After the semiconductor module 101 has reached a target temperature or lower by the semiconductor module cooling source 1001, or after the semiconductor module 101 has been cooled for a certain period of time or more, heating by the heat dissipation member heating source 1002 may be stopped.

[0025] Next, the configuration of the semiconductor device 102 according to the first embodiment will be described with reference to Fig. 5. Fig. 5 is a cross-sectional view that schematically shows the structure of the semiconductor device 102 according to the first embodiment.

[0026] The semiconductor device 102 according to the first embodiment includes a semiconductor module 101, a solder joint material 5, and a heat dissipation member 6. The semiconductor module 101 includes a sealing resin 1, a semiconductor element 2, a joining member 3, and a substrate 4. The semiconductor element 2 is mounted on the substrate 4 by the joining member 3, and the semiconductor module 101, in which the semiconductor element 2, the joining member 3, and the substrate 4 are sealed with the sealing resin 1, is joined to the heat dissipation member 6 via the solder joint material 5. The glass transition temperature of the sealing resin 1 is higher than the solidus temperature of the solder joint material 5.

[0027] Furthermore, it is desirable that the glass transition temperature of the sealing resin 1 is higher than the liquidus temperature of the solder joint material 5. It is also desirable that the melting point of the joining member 3 is higher than the liquidus temperature of the solder joint material 5.

[0028] Next, the effects of the first embodiment will be described. According to the method for manufacturing a semiconductor device according to the first embodiment, after the semiconductor module 101, the solder joint material 5, and the heat dissipation member 6 are heated, the semiconductor module 101 is cooled by the semiconductor module cooling source 1001, and the solder joint material 5 is solidified later than the sealing resin 1. Therefore, the semiconductor module 101 is cooled preferentially, and the amount of warpage of the semiconductor module 101 after the solder joint material 5 is solidified is reduced. Therefore, the stress generated in the solder joint material 5 is reduced, and it is possible to suppress the occurrence of cracks in the solder joint material 5. Therefore, it is possible to mitigate the effects of warpage of the semiconductor module 101 without using a separate material for suppressing warpage of the semiconductor module 101.

[0029] According to the method for manufacturing a semiconductor device according to the first embodiment, the semiconductor module 101 is cooled by the semiconductor module cooling source 1001, and the heat dissipation member 6 is heated by the heat dissipation member heating source 1002. Therefore, by simultaneously heating the heat dissipation member 6 and cooling the semiconductor module 101, the temperature of the semiconductor module 101 can be lowered when the temperature of the solder joint material 5 reaches or exceeds the liquidus temperature of the solder joint material 5, compared to when the heat dissipation member 6 and the semiconductor module 101 are cooled simultaneously. This reduces the amount of deformation of the semiconductor module 101 due to temperature changes after the solder joint material 5 has hardened. This reduces the thermal stress generated in the solder joint material 5, thereby preventing peeling of the solder joint material 5.

[0030] According to the manufacturing method of the semiconductor device of the first embodiment, the glass transition temperature of the sealing resin 1 is higher than the solidus temperature of the solder joint material 5. At temperatures higher than the glass transition temperature, the sealing resin 1 has a large linear expansion coefficient, and therefore the difference in linear expansion coefficient with the substrate 4 and the like increases the amount of warpage change per unit temperature. Since the glass transition temperature of the sealing resin 1 is higher than the solidus temperature of the solder joint material 5, the amount of warpage change of the semiconductor module 101 after the solder joint material 5 solidifies is reduced, and therefore the thermal stress generated in the solder joint material 5 can be reduced.

[0031] According to the method for manufacturing a semiconductor device according to the first embodiment, the glass transition temperature of the sealing resin 1 is higher than the liquidus temperature of the solder joint material 5. Since the glass transition temperature of the sealing resin 1 is higher than the liquidus temperature of the solder joint material 5, the amount of warpage change of the semiconductor module 101 is small not only after the solder joint material 5 has solidified but also in a semi-cured state that is higher than the liquidus temperature but lower than the solidus temperature. This makes it possible to prevent the semiconductor module 101 from separating from the solder joint material 5 and causing peeling.

[0032] According to the manufacturing method of the semiconductor device of the first embodiment, the melting point of the joining member 3 is higher than the liquidus temperature of the solder joining material 5. Since the melting point of the joining member 3 is higher than the liquidus temperature of the solder joining material 5, the joining member 3 does not melt even if the temperature of the joining member 3 is raised above the liquidus temperature of the solder joining material 5 in the joining step of the solder joining material 5. This makes it possible to suppress cracking of the sealing resin 1 due to volume expansion during melting.

[0033] In the semiconductor device according to the first embodiment, the glass transition temperature of the sealing resin 1 is higher than the solidus temperature of the solder joint material 5. Since the glass transition temperature of the sealing resin 1 is higher than the solidus temperature of the solder joint material 5, the amount of warpage of the semiconductor module 101 after the solder joint material 5 solidifies is reduced, and therefore the thermal stress generated in the solder joint material 5 can be reduced.

[0034] In the semiconductor device according to the first embodiment, the glass transition temperature of the sealing resin 1 is higher than the liquidus temperature of the solder joint material 5. Since the glass transition temperature of the sealing resin 1 is higher than the liquidus temperature of the solder joint material 5, the amount of warpage change of the semiconductor module 101 is small not only after the solder joint material 5 has solidified but also in a semi-cured state that is higher than the liquidus temperature but lower than the solidus temperature. This makes it possible to prevent the semiconductor module 101 from separating from the solder joint material 5 and causing peeling.

[0035] In the semiconductor device according to the first embodiment, the melting point of the joining member 3 is higher than the liquidus temperature of the solder joining material 5. Since the melting point of the joining member 3 is higher than the liquidus temperature of the solder joining material 5, the joining member 3 does not melt even if the temperature of the joining member 3 is raised above the liquidus temperature of the solder joining material 5 in the joining process of the solder joining material 5. This makes it possible to suppress cracking of the sealing resin 1 due to volume expansion during melting.

[0036] Embodiment 2 Unless otherwise specified, embodiment 2 has the same manufacturing method, configuration, and effects as embodiment 1. Therefore, the same components as embodiment 1 above are denoted by the same reference numerals, and description thereof will not be repeated.

[0037] A method for manufacturing a semiconductor device according to a second embodiment will be described with reference to Figs. 6 to 9. Fig. 6 is a cross-sectional view that schematically shows a soldering cooling step in the method for manufacturing a semiconductor device according to the second embodiment. Fig. 7 is a cross-sectional view that schematically shows a state in which the heat insulating material is integrated with the air blow cover in the soldering cooling step in the method for manufacturing a semiconductor device according to the second embodiment. Fig. 8 is a cross-sectional view that schematically shows a state in which air blow from the semiconductor module cooling source flows from the side in the soldering cooling step in the method for manufacturing a semiconductor device according to the second embodiment. Fig. 9 is a cross-sectional view that schematically shows a case in which the heat capacity of the heat dissipation member is large in the soldering cooling step in the method for manufacturing a semiconductor device according to the second embodiment.

[0038] If the semiconductor module cooling source 1001 is a means for cooling by forced convection through blown air, the air may hit the heat dissipation member 6 and cool it, thereby preventing the expected effect from being achieved.

[0039] As shown in Figure 6, in the soldering cooling process, when the semiconductor module 101 is viewed from the opposite side of the heat dissipation member 6 relative to the solder bonding material 5, the heat dissipation member 6 is covered with an air blow cover 1003 having an opening OP so that the semiconductor module 101 is exposed, and the semiconductor module 101 is cooled by air blow generated by the semiconductor module cooling source 1001.

[0040] An air blow cover 1003 is disposed on the semiconductor module cooling source 1001 side. An opening OP provided in the air blow cover 1003 is disposed directly above the semiconductor module 101. The air blow cover 1003 allows the air blow to directly hit the semiconductor module 101, but makes it less likely for the air blow to hit the heat dissipation member 6. This makes it possible to increase the temperature difference between the semiconductor module 101 and the heat dissipation member 6.

[0041] To minimize the airflow from the air blower on the heat dissipation member 6, it is preferable to position the air blow cover 1003 lower than the top of the semiconductor module 101. To minimize the airflow toward the heat dissipation member 6, it is desirable for the air blow cover 1003 and the heat dissipation member 6 to be in contact with each other. However, if the air blow cover 1003 and the heat dissipation member 6 are in contact with each other, heat from the heat dissipation member 6 is transferred to the air blow cover 1003, which makes the heat dissipation member 6 more likely to cool. For this reason, when the air blow cover 1003 and the heat dissipation member 6 are brought close enough to be in contact with each other, it is also effective to integrate the heat insulating material 1004 disposed between the air blow cover 1003 and the heat dissipation member 6 with the air blow cover 1003, as shown in FIG. 7, and bring the heat insulating material 1004 closer to the heat dissipation member 6. The heat insulating material 1004 has higher heat insulating performance than the air blow cover 1003. The heat insulating material 1004 makes it difficult for the heat from the heat dissipating member 6 to be transferred to the air blow cover 1003, so that cooling of the heat dissipating member 6 can be suppressed.

[0042] 8, the air blow direction of the semiconductor module cooling source 1001 may be from the side. It is preferable that the air blow cover 1003 is installed so as to block the air path to the heat dissipation member 6 and allow air to flow above the semiconductor module 101, rather than having a rectangular opening OP to expose the semiconductor module 101. The air blow from the semiconductor module cooling source 1001 may also flow from both the top and side.

[0043] The air blow cover 1003 may be incorporated into the equipment and mounted during the soldering cooling process, and then removed after cooling is complete, with the workpieces being transported to the subsequent process alone. Alternatively, the air blow cover 1003 may be transported as a jig together with the workpieces from the stage of being inserted into the solder joining equipment. An advantage of incorporating the air blow cover 1003 into the equipment is that the processes of mounting and retrieving it, as with a jig, are not required. On the other hand, a disadvantage of incorporating the air blow cover 1003 into the equipment is that the equipment must be reconfigured when transporting workpieces of different sizes.

[0044] Furthermore, if the heat capacity of the heat dissipation member 6 is large, the temperature of the heat dissipation member 6 is unlikely to decrease even without heating by the heat dissipation member heating source 1002. As shown in Fig. 9, the effect of this embodiment can be achieved simply by cooling the semiconductor module 101 with the semiconductor module cooling source 1001 and preventing the heat dissipation member 6 from being cooled with the air blow cover 1003.

[0045] Next, the effects of the second embodiment will be described. According to the manufacturing method of the semiconductor device of the second embodiment, the semiconductor module 101 is cooled by air blow generated by the semiconductor module cooling source 1001 in a state where the heat dissipation member 6 is covered with the air blow cover 1003 having an opening OP so that the semiconductor module 101 is exposed when the semiconductor module 101 is viewed from the side opposite the heat dissipation member 6 with respect to the solder joint material 5. The air blow cover 1003 allows the air blow to hit the semiconductor module 101 and makes it difficult for the air blow to hit the heat dissipation member 6, thereby widening the temperature difference between the semiconductor module 101 and the heat dissipation member 6. This reduces the amount of deformation of the semiconductor module 101 due to temperature changes after the solder joint material 5 has hardened. This reduces the thermal stress generated in the solder joint material 5.

[0046] Embodiment 3 Unless otherwise specified, the third embodiment has the same manufacturing method, configuration, and effects as the first embodiment. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will not be repeated.

[0047] The mechanism by which shrinkage cavities are formed in a solder joint material will be described with reference to Fig. 10 and Fig. 11. Fig. 10 is a cross-sectional view for explaining the mechanism by which shrinkage cavities are formed in a solder joint material. Fig. 11 is a cross-sectional view taken along line XI-XI in Fig. 10.

[0048] When the semiconductor module 101 is cooled while the heat dissipation member 6 is heated, the solder joint material 5 cools over time. If the time it takes for the solder joint material 5 to cool from its liquidus temperature to its solidus temperature becomes long, defects called shrinkage cavities 5a may occur in the solder joint material 5, as shown in Figures 10 and 11. Solder generally has a liquidus point at which the entire solder becomes liquid and a solidus point at which the entire solder becomes solid. At temperatures between the liquidus and solidus points, the solder is in a mixed liquid and solid state. When the solder changes from the liquidus to the solidus temperature, the volume of the solder shrinks. However, if the solder cools from the liquidus to the solidus temperature in a short time, the solder solidifies before it can flow, making defects unlikely to occur. On the other hand, if the solder cools from the liquidus to the solidus temperature over a long time, the solid portion shrinks in volume, but due to the fluidity of the liquid portion, the solder migrates to the solidified portion where the volume has contracted. When the outer periphery of the solder finally becomes solid, air enters the area where the volume of the solder is insufficient, causing shrinkage cavities 5a.

[0049] However, when the solder is cooled from the outer periphery and the center of the solder joining material 5, which is surrounded by the solder and the joined material, finally becomes solid, air cannot enter from outside the solder, and the shortage in the volume of the solder is compensated for by the thinner joint thickness, thereby preventing the occurrence of shrinkage cavities 5a.

[0050] A method for manufacturing a semiconductor device according to the third embodiment will be described with reference to Figures 12 and 13. Figure 12 is a cross-sectional view schematically showing a soldering cooling step in the method for manufacturing a semiconductor device according to the third embodiment. Figure 13 is a plan view schematically showing the soldering cooling step in the method for manufacturing a semiconductor device according to the third embodiment.

[0051] As shown in Figures 12 and 13, in the soldering cooling process, the semiconductor module 101 is cooled by a semiconductor module cooling source 1001, and the semiconductor module 101 is heated by a semiconductor module heating source 1005 arranged in the center with a gap from the outer edge of the semiconductor module 101.

[0052] A semiconductor module heat source 1005 is mounted on the semiconductor module 101. The contact area between the semiconductor module heat source 1005 and the semiconductor module 101 is smaller than the contact area between the solder joint material 5 and the heat dissipation member 6. The contact area between the semiconductor module heat source 1005 and the semiconductor module 101 is inside the area directly above the solder joint material 5.

[0053] A semiconductor module heating source 1005 made of metal or resin is mounted on the semiconductor module 101 to cool the solder bonding material 5 from the periphery and finally solidify the center. The semiconductor module heating source 1005 may be mounted on the semiconductor module 101 after being incorporated into the device and heated in the soldering cooling process. Alternatively, the semiconductor module heating source 1005 may be mounted on the semiconductor module 101 from the stage of being loaded into the solder bonding device and transported as a jig. The advantages and disadvantages of the semiconductor module heating source 1005 being incorporated into the device and transported as a jig are the same as those of the air blow cover 1003. An additional advantage of transporting the semiconductor module heating source 1005 as a jig is that the jig can be heated simultaneously in the soldering heating process. Furthermore, if the semiconductor module 101 is light, the surface tension of the solder joint material 5 may cause the semiconductor module 101 to float, which may result in the solder joint material 5 being thicker than expected after joining, but the height of the solder joint material 5 can be controlled by installing the semiconductor module heating source 1005. In this case, however, a member for controlling the height is required inside the solder joint material 5.

[0054] It is desirable that the semiconductor module heat source 1005 is smaller than the size of the semiconductor module 101 in order to heat only the vicinity of the center of the semiconductor module 101. Considering that heat spreads at 45°, it is desirable that the size of the semiconductor module heat source 1005 is smaller than the semiconductor module 101 by at least the same width as the thickness of the semiconductor module 101, and that the semiconductor module heat source 1005 is installed near the center of the semiconductor module 101.

[0055] Next, a modified example of the method for manufacturing a semiconductor device according to the third embodiment will be described with reference to Fig. 14 and Fig. 15. Fig. 14 is a cross-sectional view schematically showing a soldering cooling step in the modified example of the method for manufacturing a semiconductor device according to the third embodiment. Fig. 15 is a plan view schematically showing a soldering cooling step in the modified example of the method for manufacturing a semiconductor device according to the third embodiment.

[0056] As shown in FIGS. 14 and 15, in the soldering cooling step, the heat dissipation member 6 is heated by a contact portion 1002a of a heat dissipation member heating source 1002 disposed in the center of the heat dissipation member 6 with a gap therebetween from the outer edge thereof.

[0057] The contact area between the heat dissipation member heating source 1002 and the heat dissipation member 6 is smaller than the contact area between the solder joint material 5 and the heat dissipation member 6. The contact area between the heat dissipation member heating source 1002 and the heat dissipation member 6 is inside the area directly below the solder joint material 5.

[0058] The heat dissipation member heating source 1002 is a metal or resin plate that comes into contact with the heat dissipation member 6 to heat it. The heat dissipation member heating source 1002 is shaped so that it comes into contact with the heat dissipation member 6 only directly below the center of the solder joint material 5. In other words, the contact portion 1002a of the heat dissipation member heating source 1002 comes into contact with the heat dissipation member 6 only directly below the center of the solder joint material 5. This makes it easier for the edges of the solder joint material 5 to cool and harder for the center to cool, making it less likely that shrinkage cavities will occur.

[0059] The heat dissipation member heating source 1002 is preferably smaller than the solder joint material 5 in order to heat only the area near the center of the solder joint material 5. Considering that the heat spreads at 45°, the size of the heat dissipation member heating source 1002 is preferably smaller than the solder joint material 5 by at least the same width as the thickness of the heat dissipation member 6, and the heat dissipation member heating source 1002 is preferably installed near the center directly below the solder joint material 5.

[0060] Furthermore, when the semiconductor module cooling source 1001 is a means for cooling by forced convection using an air blow, the air blow may be applied locally instead of all over the surface as shown in FIG. 1. By applying the air blow to the outer periphery of the semiconductor module 101, cooling of the outer periphery of the solder joint material 5 is promoted, and the occurrence of shrinkage cavities can be prevented. Methods for applying the air blow locally include installing a cover as in embodiment 2, or installing an air nozzle on the equipment. Using an air nozzle allows for a larger flow rate of air to be applied locally, but has the disadvantage of requiring a change in the air blow position when trying to move workpieces of different sizes.

[0061] Next, the effects of the third embodiment will be described. According to the method for manufacturing a semiconductor device according to the third embodiment, the semiconductor module 101 is cooled by the semiconductor module cooling source 1001, and is heated by the semiconductor module heating source 1005 disposed in the center with a gap from the outer edge of the semiconductor module 101. By mounting the semiconductor module heating source 1005 in the center of the semiconductor module 101, the outer periphery of the semiconductor module 101 and the solder joint material 5 is cooled more easily than the center, and it is possible to prevent the outer periphery from hardening first and causing shrinkage cavities.

[0062] According to a modified example of the method for manufacturing a semiconductor device according to the third embodiment, the heat dissipation member 6 is heated by the contact portion 1002a of the heat dissipation member heating source 1002, which is arranged in the center with a gap from the outer edge of the heat dissipation member 6. Since the heat dissipation member heating source 1002 and the heat dissipation member 6 are in contact over a smaller area than directly below the solder joint material 5, the outer periphery of the heat dissipation member 6 and the solder joint material 5 is cooled more easily than the center, and it is possible to prevent the outer periphery from hardening first and causing shrinkage cavities.

[0063] Embodiment 4 Unless otherwise specified, embodiment 4 has the same manufacturing method, configuration, and effects as embodiment 1. Therefore, the same components as embodiment 1 above are denoted by the same reference numerals, and description thereof will not be repeated.

[0064] A method for manufacturing a semiconductor device according to the fourth embodiment will be described with reference to Figs. 16 to 19. Fig. 16 is a cross-sectional view that schematically shows a heat dissipation member cooling step in the method for manufacturing a semiconductor device according to the fourth embodiment. Fig. 17 is a cross-sectional view that schematically shows a state in which fins are provided on a heat dissipation member in the heat dissipation member cooling step in the method for manufacturing a semiconductor device according to the fourth embodiment. Fig. 18 is a cross-sectional view that schematically shows a state in which a plurality of air blow inlets are provided in the heat dissipation member cooling step in the method for manufacturing a semiconductor device according to the fourth embodiment. Fig. 19 is a cross-sectional view that schematically shows a state in which air blow inlets are biased toward the outer periphery of the solder bonding material in the heat dissipation member cooling step in the method for manufacturing a semiconductor device according to the fourth embodiment.

[0065] 16 , after the step of cooling the semiconductor module 101 while heating the heat dissipation member 6, a step of cooling the heat dissipation member 6 may be added. The method for manufacturing a semiconductor device according to the fourth embodiment further includes a step of, after the heat dissipation member 6 is heated by the heat dissipation member heating source 1002, cooling the heat dissipation member 6 by the heat dissipation member cooling source 1006 while the solder bonding material 5 is at or above its solidus temperature.

[0066] By adding a step of cooling the heat dissipation member 6, the time required for the temperature of the solder joint material 5 to drop from the liquidus temperature to the solidus temperature can be shortened, thereby suppressing the occurrence of shrinkage cavities.

[0067] The heat dissipation member cooling source 1006 may be a means for cooling by contacting a plate material and using heat transfer, a means for cooling by blowing air and using forced convection, or a means that utilizes both contact heat transfer and forced convection.

[0068] Suitable materials for the plates to be brought into contact include metals such as aluminum and copper, or metal oxides such as vanadium dioxide, which are expected to have a rapid cooling effect by utilizing the latent heat of phase change of the substance, or mixtures thereof.

[0069] When the heat dissipation member cooling source 1006 is a means for cooling by forced convection using an air blow, by blowing air only on the peripheral portion of the solder joint material 5, the edges of the solder joint material 5 are easily cooled and the center is not easily cooled, thereby suppressing the occurrence of shrinkage cavities.

[0070] 17, fins 6a may be provided on the heat dissipation member 6. A heat dissipation member cooling source 1006 is provided with a recess 1007 that receives the fins 6a of the heat dissipation member 6, and an air blow inlet 1008 that communicates with the recess 1007. Air flows in from the air blow inlet 1008.

[0071] When fins are formed on the heat dissipation member 6, a recess 1007 that matches the fins and an air blow inlet 1008 are formed in the heat dissipation member cooling source 1006, thereby forming a flow path through which the air blow flows, and the heat dissipation member 6 can be cooled more efficiently.

[0072] As shown in Fig. 18, a plurality of air blow inlets 1008 may be provided. Also, as shown in Fig. 19, the air blow inlets 1008 may be arranged biased toward the outer periphery of the solder joint material 5 in order to promote cooling of the outer periphery of the solder joint material 5.

[0073] 16 and 17 show the cooling process of the heat dissipation member 6 performed at a different position from the heating process of the heat dissipation member 6 shown in FIG. 3 and other figures, but the cooling process of the heat dissipation member 6 may be performed at the same position as the heating process of the heat dissipation member 6. For example, the heat dissipation member heating source 1002 is a heating plate, and the heat dissipation member cooling source 1006 is an air blower, and the air blow from the heat dissipation member cooling source 1006 is applied immediately after the semiconductor device 102 is separated from the heat dissipation member heating source 1002. After heating by the heat dissipation member heating source 1002 ends, the heat dissipation member 6 and the solder joint material 5 are gradually cooled by heat transfer to the semiconductor module 101 or the surrounding air. Depending on the temperature at which heating ends, the solder joint material 5 may harden before cooling by the heat dissipation member cooling source 1006, potentially causing shrinkage cavities. By performing heating and cooling at the same position, the gradual cooling period can be shortened, thereby suppressing the occurrence of shrinkage cavities.

[0074] Next, the effects of the fourth embodiment will be described. According to the manufacturing method of the semiconductor device of the fourth embodiment, after the heat dissipation member 6 is heated by the heat dissipation member heating source 1002, the heat dissipation member 6 is cooled by the heat dissipation member cooling source 1006 while the solder joint material 5 is at a temperature equal to or higher than the solidus temperature of the solder joint material 5. Therefore, by shortening the time it takes for the temperature of the solder joint material 5 to drop from the liquidus temperature to the solidus temperature, it is possible to prevent the occurrence of shrinkage cavities.

[0075] According to the semiconductor device manufacturing method of the fourth embodiment, the heat dissipation member 6 is provided with fins 6a, and the heat dissipation member cooling source 1006 is provided with recesses 1007 and air blow inlets 1008, through which air flows in. When the semiconductor device 102 comes into contact with the heat dissipation member cooling source 1006 to be cooled, the air flowing in from the air blow inlet 1008 is prevented from flowing out of the fins by the recesses 1007 aligned with the fins 6a, and instead passes through the inside of the fins. This promotes cooling of the semiconductor device 102, thereby suppressing the occurrence of shrinkage cavities.

[0076] The above embodiments can be combined as appropriate. The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0077] 1 sealing resin, 2 semiconductor element, 3 bonding material, 4 substrate, 5 solder bonding material, 6 heat dissipation material, 6a fin, 101 semiconductor module, 102 semiconductor device, 1000 semiconductor device heat source, 1001 semiconductor module cooling source, 1002 heat dissipation material heat source, 1002a contact portion, 1003 air blow cover, 1004 heat insulating material, 1005 semiconductor module heat source, 1006 heat dissipation material cooling source, 1007 recessed portion, 1008 air blow inlet, OP opening.

Claims

1. a step of mounting a semiconductor element on a substrate with a bonding member, and sealing the semiconductor element, the bonding member, and the substrate with a sealing resin to form a semiconductor module, the semiconductor module, the solder bonding material, and the heat dissipation member being placed on the heat dissipation member via a solder bonding material; and a step of heating the semiconductor module, the solder joint material, and the heat dissipation member, and then cooling the semiconductor module by a semiconductor module cooling source, and solidifying the solder joint material later than the sealing resin.

2. 2. The method for manufacturing a semiconductor device according to claim 1, wherein the semiconductor module is cooled by the semiconductor module cooling source, and the heat dissipation member is heated by a heat dissipation member heating source.

3. 3. The method for manufacturing a semiconductor device according to claim 2, wherein the semiconductor module is cooled by air blow generated by the semiconductor module cooling source while the heat dissipation member is covered with an air blow cover having an opening so that the semiconductor module is exposed when the semiconductor module is viewed from the opposite side of the heat dissipation member relative to the solder bonding material.

4. 4. The method for manufacturing a semiconductor device according to claim 1, wherein the semiconductor module is cooled by the semiconductor module cooling source and heated by a semiconductor module heating source arranged in the center with a gap from the outer edge of the semiconductor module.

5. 4. The method for manufacturing a semiconductor device according to claim 2, wherein said heat dissipation member is heated by a contact portion of said heat source disposed at the center of said heat dissipation member with a gap from the outer edge of said heat dissipation member.

6. 4. The method for manufacturing a semiconductor device according to claim 2, further comprising a step of cooling the heat dissipation member by a heat dissipation member cooling source while the solder joint material is at a temperature equal to or higher than the solidus temperature of the solder joint material after the heat dissipation member is heated by the heat dissipation member heating source.

7. The heat dissipation member is provided with fins, the heat dissipation member cooling source is provided with a recessed portion that receives the fins of the heat dissipation member, and an air blow inlet that communicates with the recessed portion; The method for manufacturing a semiconductor device according to claim 6 , wherein air flows in through the air blow inlet.

8. 4. The method for manufacturing a semiconductor device according to claim 1, wherein the glass transition temperature of the sealing resin is higher than the solidus temperature of the solder bonding material.

9. The method for manufacturing a semiconductor device according to claim 8 , wherein the glass transition temperature of the sealing resin is higher than the liquidus temperature of the solder bonding material.

10. The method for manufacturing a semiconductor device according to claim 9 , wherein the melting point of the bonding member is higher than the liquidus temperature of the solder bonding material.

11. a semiconductor module including a sealing resin, a semiconductor element, a bonding member, and a substrate; a solder joint material; a heat dissipation member, the semiconductor element is mounted on the substrate by the bonding member, and the semiconductor module in which the semiconductor element, the bonding member, and the substrate are sealed with the sealing resin is joined to the heat dissipation member via the solder bonding material, The semiconductor device, wherein the glass transition temperature of the sealing resin is higher than the solidus temperature of the solder bonding material.

12. The semiconductor device according to claim 11 , wherein the glass transition temperature of the sealing resin is higher than the liquidus temperature of the solder bonding material.

13. The semiconductor device according to claim 11 , wherein the melting point of the bonding member is higher than the liquidus temperature of the solder bonding material.

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