JP2011181634A - Method of manufacturing heat dissipation structure for mounting semiconductor heating component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat dissipation structure which has a brazing joint structure employing an aluminum-based plated steel plate as a raw material of a shock absorbing material, the heat dissipation structure having, in particular, durability to thermal shock. <P>SOLUTION: A method of manufacturing a heat dissipation structure for mounting a semiconductor heating component is provided by which, when the heat dissipation structure for mounting the semiconductor heating component is manufactured by brazing and joining an insulating substrate 2, the aluminum-based plated steel plate 3, and a heat transfer material 4 together, brazing filler metal 5 and 6 are interposed between an aluminum-based metal layer A of the insulating substrate 2 and the aluminum-based plated steel plate 3, and between the aluminum-based plated steel plate 3 and heat transfer material 4 respectively, and brazing is carried out in a state wherein an interfacial exposed part 7 between a ceramic plate 21 and the aluminum-based metal layer A is coated with a heat-resisting coating 8 which does not react with molten metal of the brazing filler metal. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a heat dissipation structure for mounting a semiconductor heat generating component composed of a semiconductor element, an LSI, or the like, and transferring heat generated from the heat generating component to the air or other joining members.

  A semiconductor heat generating component represented by a semiconductor switching element for power control is used in a state of being attached to a heat dissipation structure. The heat dissipating structure includes an “insulating substrate” in which a metal is bonded to the surface of ceramics and a metal “heat transfer material”. The heat transfer material may itself be a heat sink for dissipating heat into the air, or may be a heat radiating plate for releasing heat to other members.

  Since the metal of the heat transfer material has a larger coefficient of thermal expansion than the ceramics of the insulating substrate, if the heat sink and the heat transfer material are joined directly by brazing, the heat transfer material is likely to warp during the heating / cooling process at the time of joining. In addition, the insulating substrate is easily cracked. For this reason, a “buffer material” may be interposed between the insulating substrate and the heat transfer material to relieve strain caused by the difference in thermal expansion between the two.

  Conventionally, a clad material having a three-layer structure in which a Cu—Mo alloy having a low coefficient of thermal expansion is sandwiched between copper materials is used as the buffer material. However, the Cu—Mo alloy has various problems such as being very expensive, having a thickness as thick as about 3 mm, and being difficult to braze to a heat sink and using a gel-based adhesive.

  Patent Document 1 describes that a laminated body in which a low thermal expansion material (Invar alloy) is sandwiched between high thermal conductive materials (aluminum, copper) is interposed between an insulating substrate and a heat sink. However, it is not always easy to integrate the low thermal expansion material and the high thermal conductivity material.

  In recent years, with the spread of hybrid vehicles and electric vehicles, the demand for power modules (units for power control semiconductor circuits and heat dissipation structures) for use in power control units (PCUs) that control their drive motors has increased. Yes. In such applications, it is desired to apply a heat dissipation structure that is more resistant to vibration, more compact, and less expensive in the future.

  Therefore, the present applicant disclosed in Patent Document 2 a heat radiating device using a hot-dip aluminum-based plated steel sheet having a ferritic steel type as a plating base plate as a material for a buffer material. Ferritic steel grades have a lower coefficient of thermal expansion than heat sink materials (for example, aluminum), so the use of aluminum-plated steel plates with the plating base as the buffer material reduces the strain between the insulating substrate and the heat sink. It became possible to reduce effectively. Moreover, the aluminum-based plated steel sheet can be mass-produced, and a significant cost reduction has been realized as compared with the cushioning material using the special alloy as described above. In particular, when DBA (Direct Brazed Aluminum) is used as an insulating substrate and an Al-based material is used as a heat sink, the “insulating substrate”, “aluminum-based plated steel plate” and “heat sink” can be integrated by vacuum brazing. . In this case, since bonding with an adhesive or grease is avoided, vibration resistance and thermal conductivity are improved, and a bonding step with an adhesive or the like is not required. Moreover, since a thin aluminum-plated steel sheet having a plate thickness of, for example, 1 mm or less can be easily applied as a buffer material, the heat dissipation structure can be downsized.

JP 2004-153075 A JP 2009-158715 A

  Recently, there is an increasing number of cases where a power semiconductor element (IGBT or the like) of a type capable of applying a high voltage is adopted in a PCU or the like of a hybrid vehicle. Along with this, even higher durability is required for the heat dissipating structure on which the semiconductor heat generating component is mounted. The heat dissipating structure disclosed in Patent Document 2 described above has a brazed joint structure using a molten aluminum steel plate as a material for the buffer material, and thus exhibits high durability against vibration. However, according to the inventors' subsequent studies, it has been found that the heat dissipating structure of Patent Document 2 has room for improvement in terms of durability against “thermal shock”. In other words, it was confirmed that peeling occurred at the interface between the ceramic and the aluminum layer constituting the DBA of the insulating substrate in a test under severe conditions in which a thermal shock repeatedly fluctuating the amount of heat generated from the semiconductor heat generating component was confirmed. It was. In order to maintain high reliability even when a high-voltage application type power semiconductor element such as an IGBT is mounted, it is desired to improve durability against thermal shock.

  The present invention provides a heat dissipation structure having a brazed joint structure in which an aluminum-based plated steel sheet is used as a material for a buffer material, and particularly improved in durability against thermal shock.

  The inventors have conducted a detailed investigation on the cause of interfacial delamination between the ceramics and the aluminum layer. As a result, it was found that the molten metal infiltrated into the interface at the time of brazing and reacted with the aluminum layer to generate a new metal phase at the interface. Based on such knowledge, the present invention performs brazing in such a state that the portion where the interface is exposed is covered with a heat-resistant coating film. In this specification, the molten metal of the brazing material is referred to as “brazing material molten metal”.

That is, in the present invention, an “insulating substrate” made of a plate-like material having an aluminum-based metal layer A on at least one surface of a ceramic plate, an “aluminum-based plated steel plate” having aluminum-based plating layers on both surfaces of a base steel plate, aluminum When manufacturing a heat dissipation structure for mounting a semiconductor heating component on the insulating substrate by brazing and joining a "heat transfer material" made of a metallic metal material,
A brazing material is interposed between the aluminum-based metal layer A of the insulating substrate and the aluminum-based plated steel plate, and between the aluminum-based plated steel plate and the heat transfer material, and the interface exposed portion between the ceramic plate and the aluminum-based metal layer A is brazed. Provided is a method for manufacturing a heat-dissipating structure for mounting a semiconductor heating component, which is brazed in a state where it is coated with a heat-resistant coating that does not react with the molten metal.

  In the present specification, the “aluminum-based metal” is pure aluminum or an aluminum alloy, and the aluminum alloy here has the highest Al content (mass%) among the alloy elements, and the solidus temperature is It means a material having a temperature higher than the liquidus temperature of the brazing material used when integrating the heat dissipation structure. Examples of pure aluminum and aluminum alloys include those specified in the component table of JIS H4000: 2006.

The “aluminum-based plated steel sheet” as used in the present specification has a pure Al plated layer or an Al—Si alloy plated layer containing Si in a range of 12 mass% or less on both surfaces of a base steel sheet (plating original sheet). is there. It is desirable to employ a molten aluminum-based plated steel sheet having a plating layer thickness of 5 to 50 μm per side. Moreover, it is preferable to employ a steel type having a linear expansion coefficient (normal temperature) of 13 × 10 ⁻⁶ / K or less as the base steel plate (plating original plate). In consideration of corrosion resistance, it is advantageous to use a ferritic steel type specified in Table 4 of JIS G4305: 2005 or Table 3 of JIS G4312 for the base steel sheet. The plate | board thickness of a base-material steel plate (plating original plate) is 0.1-2 mm, for example.

  An example of the ceramic plate of the insulating substrate is AlN. As the brazing material, an Al—Si—Mg alloy having a liquidus temperature of 570 to 600 ° C. or an Al—Cu—Si—Mg alloy having a liquidus temperature of 520 to 545 ° C. can be preferably used.

  The semiconductor heat generating component is a target of various semiconductor elements, LSIs, and the like, but a power control switching element having a large heat generation amount is a preferable target.

According to the present invention, the following advantages can be obtained.
(1) Since an aluminum-based plated steel sheet, which is an inexpensive material, is used as the material for the cushioning material, the cost of the heat dissipation structure can be reduced.
(2) Since the insulating substrate, the aluminum-based plated steel plate, and the heat transfer material (for example, heat sink) can be directly joined by vacuum brazing, the manufacturing process is shortened and the obtained heat dissipation structure is strong against vibration. .
(3) Heat dissipation without brazing material molten metal entering from the interface between the ceramic plate of the insulating substrate and the aluminum-based metal layer during brazing, and no reaction phase between the aluminum-based metal layer and the brazing material molten metal at the interface. A structure is constructed. This improves durability against thermal shock.
(4) Since the thickness of the cushioning material can be easily reduced to, for example, about 1 mm or less, it is easy to cope with downsizing of the power module.

The figure which showed typically the cross section of the conventional thermal radiation structure (state which mounted the semiconductor heat-emitting component) which used the aluminum-plated steel plate as a raw material of a buffer material. The figure which showed typically the cross-sectional state of the material (laminated body) with which it uses for brazing in this invention. The figure which showed typically the cross section of the heat dissipation structure (state which mounted the semiconductor heat-emitting component) after brazing obtained by this invention. The SEM photograph of the area | region corresponded to FIG. 3 code | symbol 25 in the thermal radiation structure (comparative example) which brazed and joined without coat | covering the interface exposed part 7 using the Al-Si-Mg type | system | group brazing material. The SEM photograph of the area | region corresponded to FIG. 3 code | symbol 25 in the thermal radiation structure (example of this invention) which brazed and joined in the state which coat | covered the interface exposed part 7 with the heat-resistant coating film 8 using the Al-Si-Mg type | system | group brazing material. The SEM photograph of the area | region corresponded to FIG. 3 code | symbol 25 in the thermal radiation structure (comparative example) which brazed and joined without coat | covering the interface exposed part 7 using the Al-Cu-Si-Mg type | system | group brazing material. SEM in a region corresponding to reference numeral 25 in FIG. 3 in a heat dissipation structure (example of the present invention) in which an interface exposed portion 7 is brazed and bonded using an Al—Cu—Si—Mg based brazing material. Photo.

  FIG. 1 schematically shows a cross section of a conventional heat dissipating structure (a state in which a semiconductor heat generating component is mounted) using an aluminum-plated steel sheet as a buffer material. For convenience of explanation, this drawing partially exaggerates the dimension in the thickness direction and the like, and does not reflect the actual dimensional shape as it is (the same applies to FIGS. 2 and 3 described later). The insulating substrate 20, the buffer material 30, and the heat transfer material 40 are joined and laminated by brazing metals 50 and 60 in order from the semiconductor heating component 1 side. Heat generated from the semiconductor heat generating component 1 is transmitted through the laminated structure and radiated from the heat transfer material 40 to the outside.

  The insulating substrate 20 after brazing has an aluminum-based metal layer A on the surface of the ceramic plate 21 on the buffer material 30 side. A conductive layer 23 is provided on the semiconductor heating component 1 side. When DBA (Direct Brazed Aluminum) is used as the insulating substrate 20, the conductive layer 23 is also an aluminum-based metal layer. The aluminum-based metal layer A after brazing is thinner than the state before brazing by the thickness of the portion (A ′) that has reacted with the brazing filler metal.

  The brazing material 30 after brazing is configured by a portion corresponding to the base steel plate 31 of the aluminum-based plated steel plate used as the material. The aluminum-based plating layer reacts with the brazing material molten metal during brazing, and constitutes a part of the brazing metal 50 or 60. A part of the surface portion of the heat transfer material 40 after brazing also reacts with the brazing material molten metal during brazing. Since the base steel plate 31 is an iron-based material, its thermal expansion coefficient is an intermediate value between the insulating substrate 20 (low thermal expansion coefficient) and the heat transfer material 40 (high thermal expansion coefficient). For this reason, the base steel plate 31 exhibits an action of relaxing strain caused by a difference in thermal expansion generated between the insulating substrate 20 (low thermal expansion coefficient) and the heat transfer material 40. Moreover, the effect | action which restrains the thermal expansion of the heat-transfer material 40 is exhibited, and the "warp" of the heat-transfer material 40 at the time of brazing or use is reduced.

  In the present specification, the “brazing metal” refers to a portion that has melted and solidified during brazing. Specifically, the brazing metal 50 is composed of a part derived from the brazing filler metal, an aluminum-based metal layer-derived part A ′ and an aluminum-based plating layer-derived part 32 ′ that has melted and solidified by reacting with the brazing filler metal. Is done. The brazing metal 60 is composed of a brazing filler metal-derived portion, an aluminum-based plating layer-derived portion 33 'and a heat transfer material-derived portion 4' that have melted and solidified by reacting with the brazing filler metal.

  The heat transfer material 40 is made of an aluminum-based metal and may itself be a heat sink for releasing heat into the air, or for releasing heat to another contact member (for example, a water-cooled metal member). An aluminum-based metal plate (heat radiating plate) may be used. FIG. 1 schematically shows a heat sink.

  Thus, a heat dissipation structure in which an insulating substrate having an aluminum-based metal layer on its surface and a heat transfer material made of an aluminum-based metal are brazed and bonded via an aluminum-based plated steel plate includes an insulating substrate, a buffer material, and a heat transfer material. When the material adheres tightly to the brazing metal 50, 60, it exhibits good thermal conductivity and vibration resistance. However, due to the use of the brazing material having good wettability with the aluminum-based metal, a part of the brazing material molten metal covers the end surface portion of the aluminum-based metal layer A constituting the insulating substrate by surface tension during brazing. A phenomenon occurs in which the light is transmitted to the exposed portion of the interface 10 between the ceramic plate 21 and the aluminum-based metal layer A. As a result of detailed studies, the inventors have found that this phenomenon is a factor that reduces durability against thermal shock. That is, the brazing material molten metal enters the inside of the interface 10 from the exposed portion of the ceramic plate 21 and the aluminum-based metal layer A, and the aluminum-based metal layer A reacts with the brazing material molten metal at the intrusion portion. When the brazing material intrusion reaction region 24 is formed along the interface 10, the adhesion between the ceramic plate 21 and the aluminum-based metal layer A at that portion is lowered, and when the brazing material is subjected to repeated thermal shock, It became clear that peeling occurred from the infiltration reaction region 24 as a starting point.

  In FIG. 2, the cross-sectional state of the material (laminated body) used for brazing in this invention is shown typically. In the present invention, based on the above knowledge, brazing materials 5 and 6 are interposed between the aluminum-based metal layer A of the insulating substrate 2 and the aluminum-based plated steel plate 3 and between the aluminum-based plated steel plate 3 and the heat transfer material 4, respectively. In addition, brazing is performed in a state where a portion where the interface 10 between the ceramic plate 21 and the aluminum-based metal layer A is exposed (interface exposed portion 7) is covered with a heat-resistant coating film 8 that does not react with the brazing filler metal. In FIG. 2, the film thickness of the heat-resistant coating film 8 is exaggerated.

  The insulating substrate 2 on which the semiconductor heat generating component is mounted has an aluminum-based metal layer A on at least the surface of the ceramic plate 21 on the aluminum-based plated steel plate 3 side, and a conductive layer 23 on the mounting surface of the semiconductor heat-generating component. ing. The conductive layer 23 may be the same material as the aluminum-based metal layer 22. As long as it has such a configuration, conventionally used insulating substrates are widely applied. Examples of the ceramic plate 21 include AlN. In particular, DBA substrates in which aluminum-based metal layers are joined and integrated on both surfaces of an AlN plate are widespread, and can be applied to the present invention.

The aluminum-based plated steel plate 3 before brazing is made of an aluminum-based plated steel plate having aluminum-based plated layers 32 and 33 on both surfaces of a base steel plate 31 that is a plating original plate. The base steel plate 31 constituting the aluminum-based plated steel plate 3 functions as a buffer material in the heat dissipation structure. The base steel plate 31 desirably employs a steel type having a linear expansion coefficient of 13 × 10 ⁻⁶ / K or less at room temperature (20 ° C.). The linear expansion coefficient at room temperature is about 22 to 23 (× 10 ⁻⁶ / K) for aluminum metal, about 16 to 18 (× 10 ⁻⁶ / K) for copper alloy, and about 15 for austenitic stainless steel. ˜17 (× 10 ⁻⁶ / K), and ferritic steel (including ferritic stainless steel) is about 9.5 to 12.5 (× 10 ⁻⁶ / K). On the other hand, the linear expansion coefficient of AlN is about 4.5 (× 10 ⁻⁶ / K). Therefore, it is desirable that the base steel plate 31 is made of a steel type having a linear expansion coefficient as small as possible. As a result of the examination, it was found that it is more effective to adopt a steel type having a linear expansion coefficient at room temperature of 13 × 10 ⁻⁶ / K or less. This requirement can be met by adopting a ferritic steel grade. Among these, ferritic stainless steel is particularly suitable as the base steel plate 31 in the present invention because it has a low coefficient of linear expansion and excellent corrosion resistance. In general, the coefficient of linear expansion of metals tends to increase slightly as the temperature rises, but the order of linear expansion coefficients at room temperature is almost the same as the order of linear expansion coefficients up to about 300 ° C. It may be evaluated by the linear expansion coefficient.

  As the aluminum-based plated steel sheet 3 used as the material of the buffer material, a conventionally general molten aluminum-based plated steel sheet can be adopted. What is necessary is just to select the board thickness of the base-material steel plate 31 (plating original plate) in the range of 0.1-2 mm according to a use. If the plate thickness is less than 0.1 mm, the function of suppressing cracking and warping cannot be performed sufficiently. If it is too thick, it goes against the need for miniaturization. The thickness of the aluminum-based plating layers 32 and 33 of the aluminum-based plated steel sheet 3 may be about 5 to 50 μm per side.

  As the brazing material, one for aluminum metal is applied. For example, a brazing material using an Al—Si alloy, an Al—Si—Mg alloy, an Al—Cu—Si—Mg alloy, or the like is used. As the standard material, a brazing material defined in JIS Z3263: 2002 can be used, but a material having a lower liquidus temperature is preferable. Among them, an Al—Si—Mg-based alloy having a liquidus temperature of 570 to 600, more preferably 580 to 590 ° C., and an Al—Cu alloy having a liquidus temperature of 520 to 545 ° C., more preferably 530 to 540, are used. A -Si-Mg alloy is a particularly suitable target.

  In the present invention, a technique of performing vacuum brazing in a state where the respective members are laminated is adopted. Specifically, sheet-like brazing materials 5 and 6 may be placed between the insulating substrate 2 and the aluminum-based plated steel plate 3 and between the aluminum-based plated steel plate 3 and the heat transfer material 4, respectively. However, it is important to perform brazing in such a state that the exposed portion 7 of the interface between the ceramic plate 21 and the aluminum metal layer A constituting the insulating substrate 2 is covered with the heat-resistant coating film 8 that does not react with the brazing filler metal. The heat-resistant coating film 8 prevents the molten metal of the brazing material 5 from getting wet with the end face in the vicinity of the interface exposed portion 7 of the aluminum-based metal layer A, and is shown on the interface 10 portion of the ceramic plate 21 and the aluminum-based metal layer A. The formation of the brazing material intrusion reaction region 24 shown in FIG. 1 is avoided. As a result, the durability against thermal shock is significantly improved. Here, “covering the interface exposed portion 7” means that the interface exposed portion 7 is covered together with a part of the ceramic plate 21 and a part of the aluminum-based metal layer A exposed on both sides of the interface exposed portion 7. It means covering. Particularly for the aluminum-based metal layer A, it is more preferable to cover the entire end face with the heat-resistant coating film 8.

  As the heat-resistant coating film 8, a film that does not react with an aluminum-based molten metal and has a heat-resistant temperature higher than the brazing temperature is adopted. As a paint for forming such a heat-resistant coating film, for example, a commercially available lubricant release agent using an inorganic binder used in sintered metal forming (hot press), die casting, molten metal forging, and the like can be applied. .

  FIG. 3 schematically shows a cross section of the heat dissipation structure (in a state where a semiconductor heating component is mounted) after brazing obtained by the present invention. By performing brazing in a state where the interface exposed portion between the ceramic plate 21 and the aluminum-based metal layer A is covered with the heat-resistant coating film 8, the covered portion is prevented from getting wet with the brazing filler metal, Intrusion of the brazing filler metal into the interface 10 between the ceramic plate 21 and the aluminum-based metal layer A is avoided. That is, the initial healthy state of the interface 10 is maintained without forming the brazing material intrusion reaction region 24 shown in FIG. This eliminates the problem of peeling at the interface when subjected to thermal shock. 1 has the same structure as that of FIG. 1 described above except that the interface 10 is kept healthy. Therefore, good thermal conductivity and vibration resistance are ensured by the cross-sectional form in which each material is tightly laminated. The heat-resistant coating film 8 remaining after brazing is removed if necessary.

  As shown in FIG. 2, a “insulating substrate 2” made of a DBA substrate, an “aluminum-based plated steel plate 3” having a molten Al plating layer on both sides, and a “heat transfer material 4” made of an aluminum-based metal plate are interposed as shown in FIG. The heat dissipation structure was fabricated by stacking the stacked bodies in a state of being allowed to stand, and charging the stacked bodies into a furnace and performing vacuum brazing. At that time, a brazed material (invention example) and a heat-resistant coating film 8 formed while the interface exposed portion 7 between the ceramic plate 21 of the insulating substrate 2 and the aluminum-based metal layer A is covered with the heat-resistant coating film 8 are formed. A brazed product (comparative example) was prepared.

  A commercially available DBA substrate was prepared as the insulating substrate 2. This is a material in which an aluminum-based metal plate having a thickness of 4 mm is brazed and bonded to both sides of an AlN plate having a thickness of 0.65 mm with an Al—Si-based brazing material. The dimensions of the AlN plate (corresponding to the ceramic plate 21 in FIG. 2) are 20 mm × 30 mm × 0.65 mm, and the dimensions of the aluminum metal plates on both sides (corresponding to the conductive layer 23 and the aluminum metal layer A in FIG. 2) are both It is 18 mm x 28 mm x 0.4 mm. Hereinafter, description will be made in correspondence with the reference numerals in FIG.

  Of the insulating substrate 2 that is applied to the manufacturing method of the example of the present invention, the interface exposed portion 7 between the ceramic plate 21 and the aluminum-based metal layer A, the entire end surface of the aluminum-based metal layer A, and the ceramic plate are previously formed. The entire surface facing the aluminum-plated steel plate 3 side of the portion protruding from the aluminum-based metal layer A to the outer periphery was covered with the heat-resistant coating film 8. In order to form the heat-resistant coating film 8, a lubricant release agent “Boron Coat” manufactured by Okitsumo Co., Ltd. having a heat-resistant temperature of about 800 ° C. was used. After masking the surface of the insulating substrate 2 other than the portion where the heat-resistant coating film 8 is formed with a tape so as not to cover the surface, the lubricant release agent is sprayed from a distance of about 10 cm for about 10 seconds to form the aluminum-based metal layer A. The entire interface exposed portion 7 was covered.

  As the aluminum-based plated steel plate 3, a hot-dip aluminum-based plated steel plate having a base steel plate (plating original plate) 31 of ferritic stainless steel corresponding to SUH409 defined in JIS G4312: 1991 was used. The thickness of the base steel plate 31 is 0.4 mm. The composition of the molten aluminum-based plating is Al-9 mass% Si, and the thicknesses of the aluminum-based plating layers 32 and 33 are both about 15 μm. The dimension of the aluminum-based plated steel sheet 3 used for the heat dissipation structure is 25 mm × 35 mm.

  As the heat transfer material 4, a flat aluminum metal plate (JIS H4000: 2006 alloy number 1050A equivalent material, plate thickness 5 mm) was used here. The dimension of the heat transfer material 4 is 50 mm × 50 mm × 5 mm.

  As a brazing material, an Al—Si—Mg alloy sheet having a liquidus temperature of 580 to 590 ° C. and an Al—Cu—Si—Mg alloy sheet having a liquidus temperature of 530 to 540 ° C. are prepared. did. The thickness of the brazing material sheet was 100 μm. In one heat dissipation structure, the brazing material 5 and the brazing material 6 were the same type of brazing material.

The above materials were stacked at predetermined positions in the stacking order shown in FIG. 2 and subjected to vacuum brazing. Brazing conditions were as follows: vacuum degree: 10 ⁻³ Pa, temperature: 610 ° C. (Al—Si—Mg based brazing material) or 550 ° C. (Al—Cu—Si—Mg based brazing material) for 15 min. It was set as the conditions which cooled to 300 degreeC within the furnace which maintained the vacuum, and was then air-cooled to normal temperature outside the furnace. In this way, a total of four types of heat dissipation structures were prepared, each of two types with different types of brazing material for those with and without the heat-resistant coating film 8 formed.

  Among the heat dissipation structures obtained as described above, a thermal shock test was performed on a part of each type to apply a thermal shock. In the test, the operation of alternately dipping and holding in an inert solution at −40 ° C. and 125 ° C. for 5 min each was regarded as 1 cycle (10 min / cycle), and 1000 cycles were performed.

  A sample capable of observing a cross-sectional portion corresponding to the region indicated by reference numeral 25 in FIG. 3 is taken from the heat dissipation structure before and after the thermal shock test, and the ceramic plate 21 of the insulating substrate 2 and the aluminum-based metal are observed by SEM observation. The peeling state at the interface 10 of the layer A was examined. The results are shown in FIGS. For reference, Table 1 shows the results of composition analysis by EDX for the parts a to d entered in these figures.

  FIG. 4 shows a comparative example in which brazing was performed without covering the interface exposed portion 7 using an Al—Si—Mg brazing material. In the metal portion in contact with the ceramic plate 21 (AlN), a metal phase generated by reaction with the brazing filler metal is seen. The metal phase indicated by symbol a in FIG. 4 is considered to be a Si phase in which Al is dissolved (see Table 1), which confirms that the aluminum-based metal layer A has reacted with the brazing filler metal. The metal region reacted with the brazing filler metal corresponds to the “brazing material intrusion reaction region” indicated by reference numeral 24 in FIG. After the thermal shock test, cracks are observed in the metal portion near the interface with the ceramic plate 21 (* 1 in FIG. 4), indicating that the durability against thermal shock is poor.

  FIG. 5 shows an example of the present invention in which brazing is performed in a state where the interface exposed portion 7 is covered with the heat resistant coating 8 using an Al—Si—Mg brazing material. Since the metal portion in contact with the ceramic plate 21 (AlN) is not in contact with the brazing material molten metal, the “brazing material infiltration reaction region” is not formed. Even after the thermal shock test, the tight bonding between the ceramic plate 21 (AlN) and the aluminum-based metal layer A was maintained.

  FIG. 6 is a comparative example in which brazing was performed without covering the interface exposed portion 7 using an Al—Cu—Si—Mg brazing material. In the metal portion in contact with the ceramic plate 21 (AlN), a metal phase generated by reaction with the brazing filler metal is seen. In the metal phases indicated by symbols b, c, and d in FIG. 6, the components derived from the brazing material are concentrated (see Table 1), confirming that the aluminum-based metal layer A has reacted with the brazing material molten metal. . The metal region reacted with the brazing filler metal corresponds to the “brazing material intrusion reaction region” indicated by reference numeral 24 in FIG. In this example, delamination had already occurred at the interface between the ceramic plate 21 (AlN) and the aluminum-based metal layer A immediately after brazing (before the thermal shock test) (* 2 in FIG. 6).

  FIG. 7 shows an example of the present invention in which brazing was performed in a state where the interface exposed portion 7 was covered with the heat-resistant coating film 8 using an Al—Cu—Si—Mg brazing material. As in the case of FIG. 5, the “brazing material intrusion reaction region” was not formed, and the tight bonding between the ceramic plate 21 (AlN) and the aluminum-based metal layer A was maintained even after the thermal shock test.

DESCRIPTION OF SYMBOLS 1 Semiconductor heating component 2 Insulating substrate 3 Aluminum system plated steel plate 4 Heat transfer material 4 'Heat transfer material origin part 5, 6 Brazing material 7 Interface exposure part 8 Heat-resistant coating film 10 Interface between ceramic plate and aluminum-based metal layer A 20 Brazing Subsequent insulating substrate A Aluminum-based metal layer A ′ Aluminum-based metal layer-derived portion 21 Ceramic plate 23 Conductive layer 25 SEM observation region 30 Buffer material 31 Base steel plate 32, 33 Aluminum-based plating layer 32 ′, 33 ′ Aluminum-based plating layer Origin 40 Heat transfer material after brazing 50, 60 Brazing metal

Claims (7)

An “insulating substrate” made of a plate-like material having an aluminum-based metal layer A on at least one surface of a ceramic plate, an “aluminum-plated steel plate” having an aluminum-based plated layer on both surfaces of a base steel plate, and an aluminum-based metal material When manufacturing a heat dissipation structure for mounting a semiconductor heating component on the insulating substrate by brazing and joining the “heat transfer material”,
A brazing material is interposed between the aluminum-based metal layer A of the insulating substrate and the aluminum-based plated steel plate, and between the aluminum-based plated steel plate and the heat transfer material, and the interface exposed portion between the ceramic plate and the aluminum-based metal layer A is brazed. A method for manufacturing a heat-dissipating structure for mounting a semiconductor heat-generating component, which is brazed in a state of being covered with a heat-resistant coating that does not react with the molten metal.   The method for producing a heat-radiating structure for mounting a semiconductor heating component according to claim 1, wherein the aluminum-based plated steel sheet is a molten aluminum-based plated steel sheet having a plating layer thickness of 5 to 50 µm per side. The aluminum-based plated steel sheet has a linear expansion coefficient (normal temperature) of 13 × 10 ⁻⁶ / K or less as a base steel sheet (plating original sheet). Manufacturing method of structure.   The method for producing a heat-radiating structure for mounting a semiconductor heating component according to any one of claims 1 to 3, wherein a steel type of the base steel sheet is a ferritic steel type specified in Table 4 of JIS G4305: 2005 or Table 3 of JIS G4312. .   The method for manufacturing a heat-radiating structure for mounting a semiconductor heat-emitting component according to any one of claims 1 to 4, wherein the aluminum-based plated steel sheet has a base steel sheet (plating original sheet) thickness of 0.1 to 2 mm.   The method for manufacturing a heat-radiating structure for mounting a semiconductor heating component according to any one of claims 1 to 5, wherein the ceramic plate of the insulating substrate is AlN.   2. An Al—Si—Mg alloy having a liquidus temperature of 570 to 600 ° C. or an Al—Cu—Si—Mg alloy having a liquidus temperature of 520 to 545 ° C. is used as the brazing material. The manufacturing method of the heat radiating structure for semiconductor heat-emitting component mounting in any one of -6.