JP2011216619A - Laminated structure and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a semiconductor module with high reliability in an easy method using an insulating resin adhesive sheet as a material of an insulating substrate.SOLUTION: A laminated structure 3 includes a semiconductor element 1, a lead frame 21 supporting the semiconductor element 1 via a junction layer 17, a metal foil layer 25 joined to the lead frame 21 via the junction layer 23 in an electrically conductive and thermally conductive state, an insulating resin adhesive layer 27 bonded to the metal foil layer 25, and a metal plate layer 29 serving as a thermally conductive metal layer bonded to the insulating resin adhesive layer 27 to mediate in thermal conduction to a heat sink 13.

Description

  The present invention relates to a laminated structure that can be used for, for example, a semiconductor power module on which an IGBT element is mounted and a method for manufacturing the same.

  Along with the increase in capacity of the control power element, not only the control motor but also the drive motor is changing from a DC motor to an AC motor. By using an AC motor, maintenance-free, large capacity and fine control are achieved. For this reason, the use of AC motors for high-speed railways, hybrid cars, and electric cars is progressing. Insulating substrates used in IGBT (insulated gate bipolar transistor) modules, which are the center of power elements that control AC motors, are required to have both insulating properties and thermal conductivity. Conventionally, ceramic substrates have been used. Was used in the center. The ceramic substrate is excellent in insulation and thermal conductivity and has reliability, but has the disadvantages that it is expensive, heavy, and complicated in structure. Such a drawback is a problem when the IGBT module is used for, for example, an automobile.

  In order to eliminate these drawbacks, for example, Patent Document 1 proposes to use an insulating resin adhesive sheet as a material for an insulating substrate in a power module.

JP 2007-288054 A

  When using the insulating resin adhesive sheet instead of ceramics as the material of the insulating substrate, from the structure of the IGBT module, the insulating resin adhesive sheet includes a metal plate (lead frame) electrically connected to the IGBT element, While ensuring insulation between the metal plate (spacer) that mediates heat conduction to the heat dissipating member, it has a certain degree of heat conductivity and is required to have adhesiveness to withstand thermal shock. However, the lead frame or spacer, which is a metal plate, and the insulating resin adhesive sheet have different linear thermal expansion coefficients. Therefore, in order to maintain strong adhesion, the surface of the metal plate is used for the purpose of providing an anchor effect. It is necessary to roughen the surface by mechanical treatment such as sandblasting and chemical treatment such as roughening etching.

  In addition, in order to perform adhesion by pressing a small and thick member such as a lead frame of an IGBT element and an insulating resin adhesive sheet, problems such as prevention of pressure unevenness and securing of positioning accuracy are difficult. It is necessary to adjust and solve each individual shape. For example, when the lead frame is partially bonded to the insulating resin adhesive sheet by pressing while keeping a creepage distance to ensure insulation, it is necessary to press while absorbing the thickness of the lead frame. Distortion due to uneven pressure is likely to occur and is very difficult. Further, since the resin tends to flow out to the creeping distance portion due to the press pressure, defects such as voids are likely to occur in the pressurizing portion, and the withstand voltage may be reduced.

  Further, when used as a power element, the joint surface between the insulating resin adhesive sheet and the lead frame is exposed to a high temperature for a long time. Therefore, there is a concern that copper, which is the material of the lead frame, diffuses into the insulating resin adhesive sheet layer at a high temperature, the adhesive sheet layer becomes brittle, and the adhesive force is reduced.

  As described above, in the manufacture of IGBT modules, there are many problems when using an insulating resin adhesive sheet instead of ceramics as a material for an insulating substrate and performing laminate formation by press working, and it is still practically used. It has not reached.

  Accordingly, an object of the present invention is to provide a technique capable of manufacturing a highly reliable semiconductor module by a simple technique using an insulating resin adhesive sheet as a material of an insulating substrate.

The laminated structure of the present invention is a laminated structure used for a semiconductor module,
A semiconductor element;
A lead frame for supporting the semiconductor element;
A metal foil layer joined to the lead frame in an electrically and thermally conductive manner;
An insulating resin adhesive layer adhered to the metal foil layer;
A heat transfer metal layer that mediates heat conduction to the heat radiating member, which is adhered to the insulating resin adhesive layer;
It has.

  The laminated structure of the present invention may include a metal bonding layer at a bonding portion between the lead frame and the metal foil layer.

  Further, the laminated structure of the present invention has a surface treatment on the surface of the metal foil layer in contact with the insulating resin adhesive layer and the surface of the heat transfer metal layer in contact with the insulating resin adhesive layer, respectively. It may have a layer.

  Moreover, the laminated structure of this invention may be obtained by processing the metal foil layer, the insulating resin adhesive layer, and the heat transfer metal layer from a double-sided metal-clad laminate.

  In the laminated structure of the present invention, the insulating resin adhesive layer may be formed from an epoxy resin film.

  Moreover, as for the laminated structure of this invention, the said epoxy resin film may contain a heat conductive filler.

Moreover, the manufacturing method of the laminated structure of this invention is a manufacturing method of the laminated structure used for a semiconductor module,
Preparing a double-sided metal-clad laminate in which a metal foil and a heat transfer metal layer are laminated on the front and back surfaces of the insulating resin film, and partially removing the metal foil of the double-sided metal-clad laminate by etching; ,
Bonding a metal plate to be a lead frame to the remaining metal foil other than the portion removed by etching; and
A step of further joining a semiconductor element to the outside of the metal plate to be the lead frame;
May be provided.

  In the method for manufacturing a laminated structure of the present invention, the joining step may be performed by soldering or a metal-based adhesive.

  In the laminated structure and the manufacturing method thereof according to the present invention, by using the double-sided metal-clad laminate in which the metal foil layer and the conductive metal layer are bonded to the upper and lower sides of the insulating resin bonding layer, the bonding with other members is performed by a metal bonding technique. Can only be done. Therefore, it is possible to avoid the technical problems in the press working by the conventional method and to reduce the total number of processes. Therefore, the reliability of the semiconductor module incorporating the laminated structure of the present invention can be improved.

It is sectional drawing which shows the schematic structural example of the power module provided with the laminated structure concerning 1st Embodiment. It is sectional drawing which shows the schematic structural example of the laminated structure concerning 1st Embodiment. It is sectional drawing of the double-sided metal-clad laminate used for description of the manufacturing process of a laminated structure. It is drawing explaining the manufacturing process of a double-sided metal-clad laminate. It is drawing explaining the state which etched the double-sided metal clad laminated body and patterned the metal foil of one side. It is drawing explaining the state which cut | disconnected the double-sided metal-clad laminated body after an etching, and cut | divided into the individual laminated body. It is drawing explaining an example of a joining process. It is drawing explaining the process of mounting a semiconductor element. It is drawing explaining the modification which performs a joining process and a mounting process simultaneously. It is sectional drawing which shows the schematic structural example of the power module provided with the laminated structure concerning 2nd Embodiment. It is sectional drawing which shows the schematic structural example of the laminated structure concerning 2nd Embodiment. It is sectional drawing which shows the schematic structural example of the power module provided with the laminated structure concerning 3rd Embodiment. It is drawing explaining the flow of resin in evaluation of a metal-clad laminate. It is drawing explaining the evaluation method of the adhesive force of an insulating layer and a copper foil layer (or copper plate layer).

[First Embodiment]
The first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view illustrating a schematic configuration example of a semiconductor module including the laminated structure according to the first embodiment. As shown in FIG. 1, a power module 100 is connected to a laminated structure 3 having a semiconductor element 1 such as an insulated gate bipolar transistor (IGBT) and a free-wheeling diode (FWD), and an external electrode terminal (not shown). Conductive members 5a, 5b, relay substrates 7a, 7b connected to the conductive members 5a, 5b, adjacent semiconductor elements 1, and bonding wires 9 connecting the semiconductor element 1 and the relay boards 7a, 7b, respectively. , And a heat sink 13 serving as a heat radiating member for exchanging heat between the case 11 for housing them and the laminated structure 3. Further, the case 11 is filled with a necessary amount of an insulating resin 15 such as silicone gel and sealed by being cured.

  In the power module 100 illustrated in FIG. 1, various modifications can be made to the configuration other than the laminated structure 3 which is a characteristic component of the present embodiment.

<Laminated structure>
Next, the configuration of the multilayer structure 3 according to the first embodiment will be described in detail with reference to FIG. The laminated structure 3 includes a semiconductor element 1, a lead frame 21 that supports the semiconductor element 1 via a bonding layer 17, and a metal that is bonded to the lead frame 21 via a bonding layer 23 so as to be electrically and thermally conductive. A foil layer 25, an insulating resin adhesive layer 27 adhered to the metal foil layer 25, a metal plate layer 29 as a heat transfer metal layer adhered to the insulating resin adhesive layer 27 and mediating heat conduction to the heat sink 13; It is equipped with. In FIG. 1, the metal plate layer 29 is provided in surface contact with the heat sink 13, but a thermally conductive member may be further interposed between the metal plate layer 29 and the heat sink 13. . A symbol L in FIG. 2 is a creepage distance described later.

  The semiconductor element 1, the lead frame 21, and the metal plate layer 29 shown in FIG. As the lead frame 21 and the metal plate layer 29, for example, a copper plate or an aluminum plate having a thickness of about 0.5 mm to 3 mm can be used.

  The lead frame 21 and the metal foil layer 25 are joined by, for example, solder, a metal adhesive, or the like. Between the lead frame 21 and the metal foil layer 25, a bonding layer 23 made of a metal material having conductivity and thermal conductivity is provided. As the material of the bonding layer 23, for example, an alloy such as silver, copper, nickel, germanium, antimony, indium, or bismuth, whose main component is tin, can be suitably used as a solder material. Moreover, as a metal adhesive, a commercial item can be obtained, for example, MAX101 (trade name) manufactured by Nihon Solder Co., Ltd. can be suitably used.

  The insulating resin adhesive layer 27 is made of an insulating material such as polyimide resin, epoxy resin, BT resin, cardo resin (fluorene resin), polysiloxane resin, polyethylene terephthalate resin, polyphenylene ether resin, epoxy resin, fluororesin, vinyl resin, phenol resin, etc. It can be formed of a functional resin material. The insulating resin adhesive layer 27 is preferably made of an insulating material with as high a heat resistance as possible. From such a viewpoint, it is preferable to use a polyimide resin, an epoxy resin, or a BT resin.

  The thickness of the insulating resin adhesive layer 27 is, for example, 10 μm to 200 μm, more preferably 12 μm to 100 μm, and more preferably 18 μm to 75 μm in the case of polyimide resin, for example, from the viewpoint of not impairing thermal conductivity while ensuring necessary dielectric strength performance. Further preferred. For example, in the case of an epoxy resin, 50 μm to 300 μm is preferable, and 80 μm to 200 μm is more preferable.

  Examples of the metal foil layer 25 include copper foil, aluminum foil, iron foil, nickel foil, beryllium foil, zinc foil, indium foil, silver foil, gold foil, tin foil, zirconium foil, stainless steel foil, tantalum foil, titanium foil, lead. Examples of the foil include magnesium foil, manganese foil, and alloy foils thereof. Among these, copper foil is preferable. The “copper foil” referred to here includes, in addition to copper, a copper alloy containing copper as a main component. The copper foil preferably has a copper content of 90% by mass or more, particularly preferably 95% by mass or more. The copper foil may contain a metal such as chromium, zirconium, nickel, silicon, zinc, and beryllium.

  The thickness of the metal foil layer 25 is, for example, preferably 12 μm to 150 μm and more preferably 12 μm to 70 μm in order to improve press workability when forming a double-sided metal-clad laminate as a raw material.

  In the metal foil layer 25 and the metal plate layer 29, it is preferable that the surface on the side in contact with the insulating resin adhesive layer 27 is subjected to a chemical surface treatment for the purpose of improving the adhesive force. Examples of such surface treatment include chemical treatment with rust prevention treatment, nickel plating treatment, roughening etching, aluminum alcoholate, aluminum chelate, silane coupling agent and the like. Among these, it is particularly preferable to carry out a rust prevention treatment. In the rust prevention treatment, for example, galvanization treatment and chromate treatment are sequentially performed on the metal foil to form a rust prevention layer (see FIG. 4). Zinc plating treatment and chromate treatment can be performed by a known method. By preventing the metal foil layer 25 and the metal plate layer 29 from being rust-prevented, metal ions such as Cu ions are prevented from diffusing into the insulating resin adhesive layer 27 from the metal foil layer 25 or the metal plate layer 29. Is done. Therefore, it is possible to prevent the weakened layer from being formed in the insulating resin adhesive layer 27 due to the diffusion of metal ions such as Cu ions, thereby deteriorating the adhesive force. As described above, by performing the surface treatment on the metal foil layer 25 and the metal plate layer 29, the adhesiveness of the insulating resin adhesive layer 27 is maintained for a long period of time. Therefore, when the laminated structure 3 is incorporated in the power module 100 of FIG. 1, for example, the reliability of the power module 100 can be improved. From such a viewpoint, it is desirable that the copper foil used for the metal foil layer 25 is a copper foil applied to electronic material applications such as a circuit wiring board. Examples of commercially available copper foil subjected to rust prevention treatment include HL foil (trade name) manufactured by Nippon Electrolytic Co., Ltd., USLP foil (trade name), WS foil (trade name) manufactured by Furukawa Electric Co., Ltd., and GTS. Foil (trade name), VLP foil (trade name) manufactured by Mitsui Kinzoku Mine Co., Ltd., HA foil (trade name) manufactured by Nikko Metal Co., Ltd., BHYA foil (trade name), etc. it can.

  In the power module 100 shown in FIG. 1, the semiconductor element 1 side and the heat sink 13 side placed at the ground potential need to be electrically insulated from each other with the insulating resin adhesive layer 27 as a boundary. From such a viewpoint, in the laminated structure 3, the insulating resin adhesive layer 27 having high withstand voltage is interposed between the semiconductor element 1 and the metal plate layer 29. In addition, if the semiconductor element 1 generates heat while being energized and cannot dissipate heat, it may cause a failure, and thus cooling must be performed efficiently. Therefore, a thin film of a resin material having a relatively low thermal resistance is used as the insulating resin adhesive layer 27 that ensures insulation, and the heat sink 13 is connected via the metal plate layer 29 so as to actively cool the semiconductor element 1. I have to.

[Manufacturing method of laminated structure]
A method for manufacturing the laminated structure 3 will be described with reference to FIGS. The manufacturing method of the laminated structure of the present embodiment can include, for example, a step of preparing a double-sided metal-clad laminate, an etching step, a bonding step, and a mounting step.

<Double-sided metal-clad laminate>
First, a double-sided metal-clad laminate 40 as shown in FIG. 3 is prepared. FIG. 4 shows an example of a state before lamination. The double-sided metal-clad laminate 40 includes a resin film 27A, a metal foil 25A, and a metal plate 29A. The resin film 27 </ b> A becomes the insulating resin adhesive layer 27 in the laminated structure 3 after processing, and is formed of the same material as the insulating resin adhesive layer 27. The metal foil 25A and the metal plate 29A become the metal foil layer 25 and the metal plate layer 29, respectively, in the laminated structure 3 after processing, and the same material as the metal foil layer 25 and the metal plate layer 29, respectively. It is formed with. As shown in FIG. 4, it is preferable to form a surface treatment layer 41 such as a rust prevention layer on the surface of the metal foil 25A and the metal plate 29A on the side in contact with the resin film 27A.

  For example, as shown in FIG. 4, the double-sided metal-clad laminate 40 can be manufactured by arranging a metal foil 25A and a metal plate 29A on both sides of a resin film 27A and bonding them together. Lamination of the resin film 27A, the metal foil 25A, and the metal plate 29A can be performed by a known method. For example, it can be performed by a normal hydro press, a vacuum type hydro press, an autoclave pressurizing vacuum press or the like. Among these, it is preferable to use a vacuum hydropress capable of obtaining a sufficient pressing pressure and preventing the oxidation of the metal foil 25A and the metal plate 29A.

When the resin film 27A is bonded to the metal foil 25A and the metal plate 29A, for example, when the resin film 27A or an adhesive surface thereof is composed of an epoxy resin, the resin film 27A is within a range of about 120 to 250 ° C. It is preferable to press while heating to a temperature, more preferably in the range of 140 to 220 ° C, more preferably in the range of 140 to 200 ° C, and the press pressure is preferably about 50 to 150 Kgf / cm ² .

  Although not shown, the double-sided metal-clad laminate 40 includes, for example, the remaining metal foil 25A or the metal foil 25A on the resin film 27A side of a two-layer laminate obtained by laminating a resin film 27A and a metal foil 25A or a metal plate 29A. One of the metal plates 29A can be overlaid and thermocompression bonded. Furthermore, the double-sided metal-clad laminate 40 is prepared by separately preparing a two-layer laminate in which a resin film and a metal foil 25A are laminated, and a two-layer laminate in which a resin film and a metal plate 29A are laminated. In addition, the resin films may be laminated and thermocompression bonded so that the metal plates 29A are on the outside. In this case, two resin films are laminated to form a resin film 27A. In any of the above cases, the thermocompression bonding method is not particularly limited, and the same laminating method and laminating conditions as described above can be employed.

  Next, a more specific configuration example of the double-sided metal-clad laminate 40 will be described by taking the case where the resin film 27A is an epoxy resin film as an example. Advantages of using an epoxy resin film include, for example, that it can be bonded by hot pressing at a relatively low temperature, and that it is easy to maintain dimensional stability during bonding processing because it is by a hot pressing at a relatively low temperature. Is mentioned.

  The epoxy resin film is an adhesive resin composition (hereinafter referred to as “resin composition” in some cases) containing the component (a) epoxy adhesive resin raw material. It is distinguished from the resin raw material). Here, the component (a) contains (a) an epoxy resin and (b) a curing accelerator as essential components. Further, from the viewpoint of improving the thermal conductivity and withstand voltage characteristics when the insulating resin adhesive layer 27 is formed, the resin composition contains the thermal conductive filler of the component (b) together with the component (a). It is preferable.

  The (a) component epoxy resin is an effective component for providing sufficient insulation, adhesion, heat resistance, mechanical strength, workability and the like as an epoxy resin film. As the component (a), known epoxy resins can be used without any particular limitation. For example, bisphenol type epoxy resins such as bisphenol A type, bisphenol F type, bisphenol S type, tetramethyl bisphenol A type, phenol novolac type, Novolak type epoxy resins such as cresol novolak type, aromatic epoxy resins such as trisphenolmethane triglycidyl ether, naphthalene type epoxy resins, fluorene type epoxy resins, dicyclopentadiene type epoxy resins, etc. Two or more kinds can be mixed and used.

  The (b) component curing accelerator is an effective component for imparting sufficient curing speed, heat resistance, mechanical strength, and the like to the epoxy resin. Examples of the curing accelerator for the component (b) include organic phosphorus compounds such as triphenylphosphine, imidazoles such as 2-phenylimidazole and 2-ethyl-4-methylimidazole, tertiary amines, and Lewis acids. Can be used. The blending ratio is appropriately selected according to the required curing time, but is generally 0.01 to 15.0, for example, with respect to 100 parts by weight of the non-volatile component of the component (a) epoxy-based adhesive resin material. It is preferable to use within the range of parts by weight.

  (A) In addition to the above essential components (A) and (B), the epoxy-based adhesive resin material of the component may contain (C) a curing agent, if necessary. The curing agent is an effective component because the epoxy resin film has sufficient insulation, adhesion, heat resistance, mechanical strength, and the like. As the component (c), what is known as a curing agent for the epoxy resin of the component (a) can be applied, and one of them is a phenol resin. Specific examples of the phenol resin include divalent phenols such as bisphenol A, bisphenol F, bisphenol S, and naphthalene diol, phenol novolac, o-cresol novolac, triphenylmethane type phenol resin, and dicyclopentadiene type phenol resin. A phenol phenyl aralkyl type resin, a phenol biphenyl aralkyl type resin, a naphthol phenyl aralkyl type resin, a trivalent or higher phenol such as a naphthol biphenyl aralkyl type resin, a divalent phenol such as bisphenol A and an aldehyde such as formaldehyde Examples include polyhydric hydroxy compounds obtained by condensation, phenol novolac resins containing triazine structure obtained from phenols, triazine ring-containing compounds and aldehydes, etc. You can. In addition, as component (c), aromatic amine curing agents such as diaminodiphenylsulfone and diaminodiphenylmethane, aliphatic amine curing agents such as ethylenediamine and hexamethylenediamine, or dicyandiamide and imidazole which are basic active hydrogen compounds Examples can be given.

  Regarding the preferred ratio of the (a) component epoxy resin and the (c) component curing agent, if the curing agent is a phenol resin, an aromatic amine curing agent, or an aliphatic amine curing agent, an epoxy resin / curing agent The equivalent ratio is 0.7 to 1.3, more preferably 0.8 to 1.2. When (imidazole) is used as the component (c), it is also calculated as the component (b) because it is a curing accelerator for the component (b). Component (C) is preferably used in such an amount that the equivalent ratio ((C) / (I)) is 0.5 to 1.5 with respect to the epoxy resin of component (A). In general, when a phenol resin curing agent is used, the equivalent ratio ((C) / (I)) is 0.8 to 1.2, and when an amine curing agent is used, the equivalent ratio ((C) / (A)) is preferably 0.5 to 1.0.

  Examples of the thermally conductive filler of component (b) that may be contained in the resin composition include aluminum nitride, boron nitride, silicon nitride, silicon carbide, magnesia (aluminum oxide), alumina (aluminum oxide), crystalline silica ( Insulating inorganic fillers such as silicon oxide and fused silica (silicon oxide). In order to improve the thermal conductivity of the epoxy resin film, these thermal conductive fillers are generally blended so that the volume filling rate of the epoxy resin film is 50% or more.

  A more specific configuration example will be described by taking as an example the case where the thermal conductive filler is an alumina powder. Advantages of the alumina powder include that it is relatively inexpensive among heat conductive fillers, and that a wide range of particle sizes can be used as a commercial product.

  When alumina powder is contained as the thermally conductive filler of component (b), the content of alumina powder per nonvolatile component of the resin composition is preferably 40 to 95% by weight, more preferably 60 to 93% by weight. The higher the content of alumina powder in the resin composition, the more desirable from the viewpoint of high thermal conductivity and low thermal expansion. If the content of alumina powder in the nonvolatile component of the resin composition is less than 40% by weight, high thermal conductivity is not sufficient. In addition, sufficient heat dissipation is not exhibited, and in addition, low thermal expansion is not sufficient, leading to a decrease in solder heat resistance. On the other hand, if it exceeds 95% by weight, the viscosity of the varnish increases, or the melt as a dried product or a film-like adhesive (hereinafter also referred to as B-stage state composition) obtained by drying the resin composition. As the viscosity increases, the workability, withstand voltage characteristics, and adhesiveness of the insulating resin adhesive layer 27 are lowered, and the surface state is deteriorated.

  Here, the nonvolatile component of the resin composition is, for example, when the resin composition is a varnish containing a predetermined solvent, and when the insulating resin adhesive layer 27 is formed using the varnish, the solvent is removed by drying or curing. It means the non-volatile component that finally remains. That is, the content rate of the alumina powder here represents the weight percentage of the alumina powder contained per non-volatile component. In addition to the essential components (a) and (b), and the component (b), the component (c) and other components are added as necessary as described below. In such a case, the component added separately is considered. The nonvolatile component of the resin composition is a notation for comprehensively defining the case of varnish. The varnish contains a solvent for the purpose of improving processability by reducing the viscosity of the resin composition. However, when the insulating resin adhesive layer 27 is finally formed, the solvent is removed by drying and curing. The content of the component in the resin composition exhibits the effect of the invention when the solvent is removed and the insulating resin adhesive layer 27 is finally formed. Therefore, it prescribed | regulated using the component content rate with respect to the non-volatile component of a resin composition.

  The maximum particle size of the alumina powder is preferably 120 μm or less, more preferably 100 μm or less. When the maximum particle diameter is larger than 120 μm, the processability as the insulating resin adhesive layer 27 is not sufficient, and the surface state of the insulating resin adhesive layer 27 tends to be deteriorated. Here, the maximum particle diameter is a particle diameter when the distribution probability of the particle diameter is equal to or greater than a certain particle diameter in the distribution curve of the volume fraction of the particle diameter when the total volume of alumina particles is 100%. Indicates the minimum value.

  Further, the above-mentioned alumina powder is preferably a spherical alumina in which the total alumina powder is preferably 90% by weight or more, more preferably 95% by weight or more. Examples of the type of alumina powder include crystalline alumina, fused alumina, and the like, and examples of the shape of the alumina powder include a spherical shape and a crushed shape. From the viewpoint of high thermal conductivity by close-packing, crystalline spherical alumina is preferable. Most suitable. When the content of crystalline spherical alumina in the alumina powder is less than 90% by weight, the viscosity when used as a varnish, or the melt viscosity as a film adhesive increases, and the processability as the insulating resin adhesive layer 27, The withstand voltage characteristics and adhesiveness tend to be lowered, and the surface condition tends to deteriorate. Here, by using crystalline alumina, an effect of increasing the thermal conductivity as compared with molten alumina can be obtained. Further, by using spherical alumina, an effect of lowering the viscosity when used as a varnish or the melt viscosity as a film adhesive can be obtained as compared with crushed alumina.

  The resin composition contains a predetermined solvent, for example, amide solvents such as N, N-dimethylformamide (DMF), N, N-dimethylacetamide, N-methyl-2-pyrrolidone (NMP), 1-methoxy-2-propano Dissolve or disperse in one or a mixture of two or more of ether solvents such as benzene, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and cyclopentanone, and aromatic solvents such as toluene and xylene. You may make it form a varnish. Among (b) curing accelerator, (c) curing agent, alumina powder as component (b), and other additives added as necessary, inorganic fillers, organic fillers, colorants, etc. As long as it is uniformly dispersed, it is not necessarily dissolved in the solvent.

  Also, a film adhesive may be formed by applying this varnish on a base film as a support and drying it, or by applying this varnish on a copper foil or copper plate and drying it. You may form a copper foil or a copper plate with an adhesive. Here, regarding the film support before curing, or the film support of the copper foil or copper plate with a film adhesive before curing, the higher the solvent residual rate, the better the film support, the solvent remaining If the rate is too high, the film-like adhesive before curing, or the copper foil or copper plate with the film-like adhesive before curing may cause tackiness or foaming may occur during curing. Therefore, the solvent residual ratio is preferably 5% by weight or less. In addition, the solvent residual rate here is the value calculated | required by the measurement of the net weight decreasing rate of a film adhesive part at the time of drying for 60 minutes in 180 degreeC atmosphere. In addition, the film-like adhesive and the copper foil or copper plate with the film-like adhesive are obtained by applying a resin composition not containing a solvent on a base film as a support material in a heated and melted state, and then cooling it. May be.

  Examples of the support material used when forming the film adhesive or the copper foil or copper plate with the film adhesive include polyethylene terephthalate (PET), polyethylene, copper foil, aluminum foil, release paper and the like. The thickness of the support material is generally 10 to 100 μm. Further, a metal foil such as copper or aluminum or a metal plate can also be used as the support material, and the manufacturing method thereof may be an electrolytic method or a rolling method.

  In addition, the film-like adhesive or the copper foil with film-like adhesive is laminated on the base film as the support material, and then the other surface that is not bonded is covered with a film as the protective material to form a roll. It can also be wound and stored. Examples of the protective material used at this time include polyethylene terephthalate, polyethylene, release paper, and the like. The thickness of the protective material is generally 10 to 100 μm.

  In addition to the essential components (A) and (B) and optional components (C) and (B), the resin composition is a film-like adhesive or a copper foil or copper plate with a film-like adhesive. From the viewpoint of improving flexibility at the time, a bisphenol type phenoxy resin can be added as necessary. Specifically, bisphenol A type phenoxy resin, bisphenol F type phenoxy resin, biphenyl type phenoxy resin, fluorene type phenoxy resin, brominated bisphenol A type phenoxy resin, brominated bisphenol F type phenoxy resin and the like can be mentioned. The weight average molecular weight of the bisphenol type phenoxy resin used is 10,000 to 200,000, preferably 20,000 to 100,000. If the weight average molecular weight is less than 10,000, the heat resistance, mechanical strength and flexibility of the resin composition may be reduced. If the weight average molecular weight is more than 200,000, solubility in organic solvents, epoxy resin, The workability such as compatibility with the curing agent may be reduced, and in addition, the viscosity as a varnish or the melt viscosity as a film adhesive increases, and the workability as the insulating resin adhesive layer 27 is increased. Adhesiveness may deteriorate or the surface condition may deteriorate. Here, the weight average molecular weight is a value in terms of polystyrene measured by GPC (gel permeation chromatography).

  The content of the bisphenol type phenoxy resin is preferably 60% by weight or less, more preferably 30% by weight or less per nonvolatile component of the resin composition. If it exceeds 60% by weight, the solubility in an organic solvent will decrease, and the workability such as compatibility with (a) an epoxy resin or (c) a curing agent will decrease, and the viscosity as a varnish The melt viscosity as a film adhesive increases, and the workability and adhesiveness as the insulating resin adhesive layer 27 are lowered, or the surface state is deteriorated. In some cases, the heat resistance tends to decrease.

  In addition, the resin composition has a film-like adhesive or a copper foil with a film-like adhesive or a copper plate, from the viewpoint of improving the film supportability and reducing the elasticity as the insulating resin adhesive layer 27, as necessary. A rubber component can be added. Examples of such a rubber component include polybutadiene rubber, acrylonitrile-butadiene rubber, modified acrylonitrile-butadiene rubber, and acrylic rubber. The weight average molecular weight of the rubber used is, for example, 10,000 to 1,000,000, preferably 20,000 to 500,000. If the weight average molecular weight is less than 10,000, the resin composition may cause a decrease in heat resistance, mechanical strength, and flexibility, and a decrease in film support in the pre-curing stage. If the weight average molecular weight is larger than 1,000,000, workability such as solubility in an organic solvent, compatibility with an epoxy resin and a curing agent may be reduced, and the viscosity as a varnish, or In some cases, the melt viscosity as a film adhesive increases, and the workability and adhesiveness as the insulating resin adhesive layer 27 may deteriorate, or the surface state may deteriorate. In addition, the weight average molecular weight here is a value in terms of polystyrene by GPC measurement. These rubbers can be used alone or in combination of two or more. In addition, the purity of the rubber used as the rubber component should be low in ionic impurities from the viewpoint of improving the withstand voltage characteristics and moisture resistance reliability.

  In addition, a fluorine-based, silicone-based antifoaming agent, leveling agent, and the like can be added to the resin composition as necessary from the viewpoint of reducing voids and improving smoothness. Further, from the viewpoint of improving the adhesion with members such as the metal foil layer 25 and the metal plate layer 29, an adhesion imparting agent such as a silane coupling agent or a thermoplastic oligomer can be added to the resin composition.

  Furthermore, you may add inorganic fillers and organic fillers other than an alumina as needed as fillers other than the alumina powder as (b) component to a resin composition. Examples of the inorganic filler in this case include silica, boron nitride, aluminum nitride, silicon nitride, calcium carbonate, magnesium carbonate and the like, and examples of the organic filler include silicon powder, nylon powder, An example is acrylonitrile-butadiene-based crosslinked rubber. About these fillers, the 1 type (s) or 2 or more types can be used.

  Furthermore, a coloring agent such as phthalocyanine / green, phthalocyanine / blue, or carbon black can be blended in the resin composition as necessary.

<Etching process>
Next, as shown in FIG. 5, the metal foil 25A of the double-sided metal-clad laminate 40 is processed into a predetermined pattern by etching. That is, the metal foil 25A of the double-sided metal-clad laminate 40 is partially removed by etching to form a plurality of patterned metal foils 25B. Etching can be performed using photolithography technology. For example, first, a predetermined resist pattern is formed on the metal foil 25A of the double-sided metal-clad laminate. Next, the exposed portion of the metal foil 25A may be etched using an etching solution such as an aqueous solution containing ferric chloride or cupric chloride as a main component, and then the resist may be peeled off.

  The etching is performed so that the resin film 27A is exposed to the outside of the patterned metal foil 25B that becomes the metal foil layer 25 when the laminated structure 3 is processed. The exposed portion of the resin film 27A serves as a cutting site when the resin film 27A and the metal foil 29A are cut in the next step.

<Cutting process>
Next, as shown in FIG. 6, the laminated resin film 27 </ b> A and the metal plate 29 </ b> A are cut in a region where the metal foil 25 </ b> A on one side has been removed by etching, and a plurality of pieces including at least one patterned metal foil 25 </ b> B are included. The laminate 50 is divided. There is no restriction | limiting in particular in the method of cutting, For example, it can carry out using press punching, a rotary saw, a water jet, etc.

  In this manner, a plurality of resin pieces 27B, a piece metal plate 29B attached to one surface of the piece resin film 27B, and a patterned metal foil 25B attached to the other surface are provided. A laminated body 50 is formed. Two or more separated patterned metal foils 25B may be formed on one small piece resin film 27B.

  Further, when the laminated structure 3 is incorporated in a power module, the patterned metal foil 25B in the cut-out laminated body 50 is used so that the insulating resin adhesive layer 27 can ensure sufficient insulation performance and pressure resistance performance. It is necessary to secure a sufficient distance (creeping distance) L between the end of the resin piece and the end of the small piece resin film 27B. The creepage distance L can be determined according to the type and size of the power module, the voltage between the semiconductor element 1 and the metal plate layer 29, and is preferably 1 mm or more and 20 mm or less, for example, 2 mm or more. More preferably, it is 10 mm or less. Thus, in the present embodiment, the creeping distance L for ensuring sufficient insulation performance can be freely adjusted by etching the metal foil 25A and cutting the resin film 27A. In addition, since etching and cutting can be performed with high-precision photolithography technology and cutting technology, the creepage distance L is higher than that of the conventional method in which the accuracy of the creepage distance L is affected by positioning in press processing. The accuracy can be specified.

<Joint process>
In the following process, a description will be given by taking one laminated body 50 as an example. In the joining step, for example, as shown in FIG. 7, the metal plate 21 </ b> A can be joined after first forming the laminate 50. The joining method can be carried out by a metal joining technique such as soldering or metal adhesive.

  In the step of joining the laminated body 50 and the metal plate 21A, as shown in FIG. 7, the solder paste 23A is applied to one of the opposing joining surfaces, and is heated and pasted. In this case, as the solder material, for example, PF305 (trade name) (melting point: 220 ° C.), FNS (trade name) (melting point: 219 ° C.), and O 3 (trade name) (melting point: 221) manufactured by Nihon Solder Co., Ltd. C.), 24 (trade name) (melting point: 240 ° C.), TFL-204-SIS (trade name) (melting point: 220 ° C.), TFL-204-151 (trade name) manufactured by Tamura Kaken Co., Ltd. Melting point: 220 ° C., TFL-204-MDS (trade name) (melting point: 213 ° C.), TFL-801-17 (trade name) (melting point: 195-209 ° C.), TFL-401-11 (product) Name) (melting point: 139 ° C.), SN100C P800 (trade name) (melting point: 227 ° C.) manufactured by Nippon Superior Co., Ltd., SN100CL (trade name) (melting point: 227 ° C.), B157 (manufactured by Nippon Superior Co., Ltd.) quotient Name) (mp; 139 ° C.), the SN88 (trade name) (mp; one hundred ninety-eight to two hundred ten ° C.), or the like can be used.

  As described above, a laminated body 60 is formed in which the lead frame 21, the bonding layer 23, the metal foil layer 25, the insulating resin adhesive layer 27, and the metal plate layer 29 are laminated in this order from the top ( (See FIG. 8).

<Mounting process>
Next, as shown in FIG. 8, the semiconductor element 1 such as an IGBT element or an FWD element is bonded onto the uppermost lead frame 21 of the stacked body 60. The joining method can be carried out by a metal joining technique using soldering, a metal adhesive or the like. FIG. 8 shows a method in which the solder paste 17A is applied to the semiconductor element 1 and bonded to the lead frame 21. In addition, since the connection of the wiring to the semiconductor element 1 can be performed by a usual method, description is abbreviate | omitted here.

  As described above, as shown in FIG. 2, the semiconductor element 1, the bonding layer 17, the lead frame 21, the bonding layer 23, the metal foil layer 25, the insulating resin adhesive layer 27, and the metal plate layer 29 are arranged in this order from the top. A laminated structure 3 can be produced. Thereafter, the power module 100 can be manufactured, for example, by joining with the heat sink 13 and forming a module in accordance with a conventional method.

<Modification>
In the above steps, the semiconductor element 1, the metal plate 21A, and the stacked body 50 can be bonded simultaneously without forming the stacked body 60. That is, the joining process and the mounting process can be performed simultaneously. For example, as shown in FIG. 9, the semiconductor element 1, the metal plate 21 </ b> A, and the laminated body 50 are arranged and aligned after solder pastes 17 </ b> A and 23 </ b> A are applied to any of the opposing joint surfaces. Two parts may be joined simultaneously.

  Furthermore, in the state of FIG. 7, the mounting process and the bonding process can be performed simultaneously by using a metal plate 21A and the semiconductor element 1 bonded together. That is, in FIG. 7, the semiconductor element 1 may be bonded to the metal plate 21 </ b> A via the bonding layer 17.

  As described above, in the manufacturing method of the laminated structure according to the present embodiment, by using the double-sided metal-clad laminate 40, it is possible to omit the adhesion by press working between the insulating resin adhesive layer 27 and the upper and lower metal plates. . That is, if the double-sided metal-clad laminate 40 is used, lamination with other members in the laminated structure 3 can be performed only by a metal bonding technique. Therefore, it is possible not only to avoid the technical problem of press working by the conventional method, but also to reduce the total man-hours.

  The production of the double-sided metal-clad laminate 40 can be carried out in the same process as the production of a double-sided metal-clad laminate for use in electronic materials such as printed boards that have already been technically established. It can be easily performed by various methods. Even when this step is performed by press working, as shown in FIG. 4, since it is a lamination press of a thin resin film 27A, a metal foil 25A and a metal plate 29A, it is constant regardless of the shape of the metal plate such as a lead frame. In addition, since the press is performed in a large area, uniform bonding is possible and pressure unevenness is unlikely to occur. Further, the number of man-hours can be reduced as compared with the conventional method in which a metal plate such as a lead frame is individually pressed.

  In addition, the creepage distance L in the insulating resin adhesive layer 27 can be ensured by partial removal of the metal foil 25A by etching the double-sided metal-clad laminate 40. The problem cannot happen. That is, it is not necessary to adjust the creepage distance L in the pressing process, which requires separate conditions in the conventional method. In addition, since the photolithography technique can be used in the etching process, it is easy to ensure the accuracy of the creepage distance L.

  In addition, since the patterned metal foil 25B exists on the small piece resin film 27B, the laminated body 50 after etching and the metal plate 21A to be the lead frame 21 are also present, for example, by soldering, metal adhesive, or the like. It can be easily performed by a conventional metal bonding technique.

  Due to the above excellent features, the reliability of the semiconductor module incorporating the laminated structure 3 can be increased.

[Second Embodiment]
Next, a configuration example of the laminated structure and the power module according to the second embodiment will be described with reference to FIGS. 10 and 11. 10 and 11, the same components as those of the first embodiment (FIGS. 1 and 2) are denoted by the same reference numerals and description thereof is omitted.

  FIG. 10 shows a power module 101 including stacked structures 3A and 3B on which different semiconductor elements are mounted. For example, the IGBT element 1A is mounted on the stacked structure 3A, and the FWD element 1B is mounted on the stacked structure 3B. The laminated structures 3A and 3B basically have the same configuration and function as those illustrated in FIG. 1, but as shown in an enlarged view in FIG. 11, the two laminated structures 3A and 3B. The insulating resin adhesive layer 27 and the metal plate layer 29 are shared. In other words, the lead frame 21, the bonding layer 23, and the metal foil layer 25 are portions that are subjected to different electrical controls on the IGBT element 1A side and the FWD element 1B side, and are therefore separated separately, but are bonded with insulating resin. The layers below the layer 27 are shared because they only need to ensure a heat conduction function.

  The laminated structures 3A and 3B having such a structure can secure a sufficient creepage distance L by pattern design in the etching process, and each of the laminated bodies 50 cut out in the cutting process has two patterned metal foils 25B. It can manufacture similarly to 1st Embodiment except the point cut | disconnected so that it may contain (refer FIG. 6). In the laminated structures 3A and 3B, two semiconductor elements (IGBT element 1A and FWD element 1B) are finally mounted on one small piece of resin film 27B. No processing is required, and since the joining can be easily performed by soldering, metal adhesive, or the like, there is no problem as in the conventional method. That is, although it is very difficult to manufacture the structure as shown in FIG. 11 by pressing a metal plate (lead frame 21) to the insulating resin adhesive layer 27 by pressing, the double-sided metal-clad laminate 40 is formed. It can be easily manufactured by using. It should be noted that on the common insulating resin adhesive layer 27, not only two but also three or more semiconductor elements can be easily mounted without restriction. Thus, the fact that the insulating resin adhesive layer 27 is shared and a plurality of semiconductor elements can be easily mounted is also a great merit of using the double-sided metal-clad laminate 40.

  Other configurations and effects of the power module 101 and the laminated structures 3A and 3B according to the present embodiment are the same as those of the first embodiment.

[Third Embodiment]
Next, a power module including a laminated structure according to the third embodiment of the present invention will be described with reference to FIG. As shown in FIG. 12, the power module 102 includes an IGBT element 1A and an FWD element 1B as two semiconductor elements. The IGBT element 1A is mounted so as to be sandwiched between the two stacked bodies 60A and 60C via the bonding layer 17 from above and below. The FWD element 1B is mounted so as to be sandwiched between the two stacked bodies 60B and 60D via the bonding layer 17 from above and below.

  The configurations of the stacked bodies 60A, 60B, 60C, and 60D are the same as those shown in FIG. 8 of the first embodiment, but in the stacked bodies 60A and 60B and the stacked bodies 60C and 60D, respectively, The metal plate layers 29C and 29D are commonly used. The metal plate layers 29C and 29D are formed larger than those in the first and second embodiments, and are disposed so as to face each other. The metal plate layers 29C and 29D are configured to mediate heat conduction to a heat sink as a heat radiating member (not shown). In addition, the metal plate layer 29 can also be individually provided in each of the stacked bodies 60A and 60B and the stacked bodies 60C and 60D.

  The manufacturing method of four laminated bodies 60A-60D is the same as that of 1st Embodiment. Finally, the two stacked bodies 60A and 60C are arranged via the IGBT element 1A, and the two stacked bodies 60B and 60D are arranged via the FWD element 1B so as to be turned upside down. Thus, a vertically symmetrical structure as shown in FIG. 12 can be obtained.

  In the power module 102, the laminates 60A, 60B, 60C, and 60D are arranged so as to sandwich the IGBT element 1A and the FWD element 1B, and the large metal plate layers 29C and 29D that are made common are sealed with the mold resin 71. By stopping, it is modularized. The power module 102 having such a double-sided cooling structure has excellent element cooling efficiency due to the heat dissipation structure provided above and below the IGBT element 1A and the FWD element 1B, and further improves the operation reliability as a power module. Can do.

  Other configurations and effects of the power module 102 according to the present embodiment are the same as those of the first embodiment.

  EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not limited at all by these Examples. In the following examples, various measurements and evaluations are as follows unless otherwise specified.

[Thermal conductivity]
Using a predetermined amount of film adhesive, heated at 180 ° C. for 10 minutes in a compression press molding machine, taken out from the press, and further heated at 180 ° C. in a dryer for 50 minutes, a diameter of 50 mm, A disk-shaped test piece having a thickness of 5 mm was obtained. The thermal conductivity of this test piece was measured by a stationary method using HC-110 manufactured by Eihiro Seiki.

Production Example 1 to Production Example 5
The raw materials and abbreviations used to obtain the resin composition for producing the epoxy adhesive film are as follows.

(A) Epoxy resin Epoxy resin (1): Bisphenol A type epoxy resin (manufactured by Toto Kasei Co., Ltd., trade name: YD128, epoxy equivalent 189, liquid)

Epoxy resin (2): Bisphenol F type epoxy resin (manufactured by Toto Kasei Co., Ltd., trade name: YF-170, epoxy equivalent 170, liquid)

Epoxy resin (3): o-cresol novolac epoxy resin (manufactured by Nippon Kayaku Co., Ltd., trade name: EOCN-1020-55, epoxy equivalent 200, softening point 55 ° C.)

(B) Curing agent Curing agent (1): Dicyanamide (active hydrogen equivalent 21)

Curing agent (2): phenol novolak (manufactured by Gunei Chemical Industry Co., Ltd., PSM-4261, phenolic hydroxyl group equivalent 105, softening point 80 ° C.)

(C) Curing accelerator Curing accelerator (1): 2-ethyl-4-imidazole

(D) Phenoxy resin Phenoxy resin (1): Bisphenol A type phenoxy resin (manufactured by Toto Kasei Co., Ltd., YP-50)

Phenoxy resin (2): Bisphenol AF type phenoxy resin (manufactured by Toto Kasei Co., Ltd., YP-70)

Phenoxy resin (3): Bisphenol S type phenoxy resin (manufactured by Toto Kasei Co., Ltd., YPS-007)

(E) Alumina powder Alumina powders (1) to (3) shown in Table 1 were used. Each item in the table was determined as described below.

[Particle size distribution parameter of alumina powder]
The alumina powder to be measured was weighed and mixed in a 0.2 wt% sodium hexametaphosphate solution as a dispersion medium so that the sample concentration was 0.04 wt%, and dispersed using an ultrasonic homogenizer for 3 minutes. The particle size distribution of this alumina dispersion was measured from the scattered light obtained by irradiation with a semiconductor laser having a wavelength of 780 nm, using a particle size distribution measuring device Microtrac MT3300EX (manufactured by Nikkiso Co., Ltd.).

  The maximum particle size is a particle size distribution obtained by the above measurement method. When the total particle volume is 100%, the distribution curve of the volume fraction of the particle size has all the particle distribution probabilities above a certain particle size. The minimum value of the particle diameter when 0 is shown.

The average particle diameter D ₅₀ is the particle diameter when the particle volume distribution obtained by the measurement method is 50% cumulative in the cumulative curve of the volume fraction of the particle diameter, assuming that the total particle volume is 100%. Show.

  Using the raw materials shown above, they were blended in the proportions shown in Table 2. First, only the phenoxy resin was stirred and dissolved in methyl ethyl ketone (MEK) in a container equipped with a stirring device. Next, an epoxy resin, a curing agent, and a curing accelerator were blended in this solution, and stirred and dissolved. Thereafter, alumina powder was blended in the varnish, stirred and dispersed to prepare a resin composition varnish. This resin composition varnish was applied to a release-treated PET film (product name: MR-50, manufactured by Mitsubishi Chemical Corporation) having a thickness of 50 μm so that the thickness of the resin layer after drying was 150 μm. After drying at 5 ° C. for 5 minutes, film-like adhesive sheets (epoxy resin films in a B stage state) 1 to 5 were prepared by peeling from the release-treated PET film. In addition, the numerical value of the compounding quantity in Table 2 shows a weight part.

[Example 1]
Epoxy high thermal conductive resin adhesive sheet (manufactured by Nippon Steel Chemical Co., Ltd., trade name: NEX160, alumina content 93% by weight, solid content 120 μm, thermal conductivity 6 W / mk) of resin composition to 150 mm × 150 mm It cut | disconnected and peeled from the support base material and prepared the epoxy resin film of the B stage state. Copper foil 1 (Furukawa Electric Co., Ltd., trade name: F2WS-18, thickness 18 μm, surface roughness Rz = 3.0 of the surface in contact with the film) and copper plate 1 (thickness) obtained by cutting this film into 150 mm × 150 mm 1mm, sandwiching the surface in contact with the film with a rust preventive treatment), after thermocompression bonding in the atmosphere at a temperature of 180 ° C, a pressure of 4MPa, and a time of 10 minutes, then heat curing in a heat oven at 180 ° C for 60 minutes, The laminated board 201 comprised from the copper foil layer 201a, the insulating layer 201b, and the copper plate layer 201c was produced.

  Next, the laminated plate was etched to form a copper foil layer 201a ′ (length × width × thickness = 50 mm × 50 mm × 18 μm). The insulating layer 201b ′ and the copper plate layer 201c ′ are cut so that the vertical and horizontal directions are 5 mm larger than the copper foil layer 201a ′, and the copper foil layer 201a ′ (vertical × horizontal × thickness = 50 mm × 50 mm × 18 μm), insulating layer A laminate 201 ′ composed of 201b ′ (length × width × thickness = 60 mm × 60 mm × 120 μm) and a copper plate layer 201c ′ (length × width × thickness = 60 mm × 60 mm × 18 μm) was produced. After applying a solder paste (trade name; Solder paste LFSOLDER TLF-204-151) on the entire surface of the copper foil layer 201a ′ of the produced laminate 201 ′, a copper plate 201a ″ (vertical) × width × thickness = 50 mm × 50 mm × 1 mm) were superposed, heated in a hot air oven preset at 310 ° C. for 20 minutes to dissolve the solder paste, and solder-bonded to produce a metal-clad laminate 201.

[Example 2]
In the same manner as in Example 1 except that the film-like adhesive sheet 1 (thermal conductivity 10 W / mk) prepared in Preparation Example 1 was used in place of the epoxy high thermal conductive resin adhesive sheet in Example 1, metal tension was applied. A laminated plate 202 was produced.

[Example 3]
In the same manner as in Example 1 except that the film-like adhesive sheet 2 (thermal conductivity 10 W / mk) prepared in Preparation Example 2 was used instead of the epoxy high thermal conductive resin adhesive sheet in Example 1, a metal-clad sheet was used. A laminated plate 203 was produced.

[Example 4]
In the same manner as in Example 1 except that the film-like adhesive sheet 3 (thermal conductivity 10 W / mk) prepared in Preparation Example 3 was used instead of the epoxy high thermal conductive resin adhesive sheet in Example 1, a metal-clad sheet was used. A laminate 204 was produced.

[Example 5]
In the same manner as in Example 1 except that the film-like adhesive sheet 4 (thermal conductivity 10 W / mk) prepared in Preparation Example 4 was used instead of the epoxy high thermal conductive resin adhesive sheet in Example 1, a metal-clad sheet was used. A laminated plate 205 was produced.

[Example 6]
In the same manner as in Example 1 except that the film-like adhesive sheet 5 (thermal conductivity 10 W / mk) prepared in Preparation Example 5 was used instead of the epoxy high thermal conductive resin adhesive sheet in Example 1, a metal-clad sheet was used. A laminated plate 206 was produced.

[Comparative Example 1]
An epoxy high thermal conductive resin adhesive sheet (manufactured by Nippon Steel Chemical Co., Ltd., trade name: NEX160) was cut into 60 mm × 60 mm, peeled from the support substrate, and an epoxy resin film in a B stage state was prepared. On one side of this film, a commercially available oxygen-free copper plate 203 (JIS C1020, length × width × thickness = 60 mm × 60 mm × 1 mm, no surface roughening treatment) was placed, and two PET films were used on the resin side and After sandwiching the copper foil side, using a vacuum laminating apparatus, temporary pressure bonding was performed under reduced pressure at a temperature of 100 ° C., a pressure of 0.4 MPa, and a time of 1 minute. A commercially available oxygen-free copper plate 203 ′ (JIS C1020, length × width × thickness = 50 mm × 50 mm × 1 mm, surface roughness) having a different size is provided at the center of the resin-side surface of the epoxy resin film with an oxygen-free copper plate temporarily attached. Without heat treatment), and thermocompression bonding in the atmosphere under the conditions of a temperature of 180 ° C., a pressure of 4 MPa, and a time of 10 minutes, followed by heat curing in a heat oven at 180 ° C. for 60 minutes to produce a metal-clad laminate 203 did. The thermocompression bonding at this time was performed by using a cushion material and a release sheet in the same manner as in Example 1.

[Comparative Example 2]
An epoxy high thermal conductive resin adhesive sheet (manufactured by Nippon Steel Chemical Co., Ltd., trade name: NEX160) was cut into 60 mm × 60 mm, peeled from the support substrate, and an epoxy resin film in a B stage state was prepared. A commercially available oxygen-free copper plate 204 (JIS C1020, length × width × thickness = 60 mm × 60 mm × 1 mm), which was previously subjected to sandblasting (treatment conditions: alumina # 220, air pressure 0.4 MPa) on one surface of the film. After placing the surface roughness Rz = 3.5) of the surface in contact with the film and sandwiching the resin side and the copper foil side with two PET films, using a vacuum laminator, the temperature is 100 ° C. under reduced pressure, Temporary pressure bonding was performed under the conditions of pressure 0.4 MPa and time 1 minute. A commercially available oxygen-free copper plate 204 ′ (JIS C1020, vertical × horizontal × thickness) having a different size, which has been subjected to a sandblasting treatment similar to the above, at the center of the resin-side surface of the epoxy resin film with an oxygen-free copper plate temporarily attached. = 50 mm × 50 mm × 1 mm, surface roughness Rz = 3.5) of the surface in contact with the film, and after thermocompression bonding in the atmosphere under the conditions of temperature 180 ° C., pressure 4 MPa, time 10 minutes, 180 ° C., 60 A metal-clad laminate 204 was produced by heat-curing with a heat oven for a minute. The thermocompression bonding at this time was performed in the same manner as in Example 1 by using two kraft papers sandwiched between stainless steel plates as a cushioning material, and using a cushioning material and a release sheet.

[Comparative Example 3]
An epoxy high thermal conductive resin adhesive sheet (manufactured by Nippon Steel Chemical Co., Ltd., trade name: NEX160) was cut into 60 mm × 60 mm, peeled from the support substrate, and an epoxy resin film in a B stage state was prepared. A commercially available oxygen-free copper plate 205 (JIS C1020, length × width × thickness = 60 mm × 60 mm ×) that has been wet-blasted (processing conditions; alumina # 320, air pressure 0.2 MPa) in advance on one surface of the film. 1 mm, the surface roughness Rz = 2.0) of the surface in contact with the film, the resin side and the copper foil side were sandwiched between two PET films, and then a vacuum laminator was used and the temperature was 100 ° C. under reduced pressure. Temporary pressure bonding was performed under the conditions of a pressure of 0.4 MPa and a time of 1 minute. A commercially available oxygen-free copper plate 205 ′ (JIS C1020, vertical × horizontal × thickness) having a different size and subjected to the same wet blasting treatment as described above at the center of the resin-side surface of the epoxy resin film with an oxygen-free copper plate temporarily attached. The surface roughness Rz = 2.0) of the surface in contact with the film is 50 mm × 50 mm × 1 mm, and after thermocompression bonding in the atmosphere at a temperature of 180 ° C., a pressure of 4 MPa, and a time of 10 minutes, 180 ° C. The metal-clad laminate 205 was produced by heat curing with a heat oven for 60 minutes. The thermocompression bonding at this time was performed by using a cushion material and a release sheet in the same manner as in Example 1.

[Evaluation of metal-clad laminate]
1) Resin flow after thermocompression bonding (resin swell from the copper end)
In Comparative Examples 1 to 3, in the manufacturing process of each metal-clad laminate, when copper plates of different sizes are thermocompression bonded, the copper plate is pushed into the insulating layer and at the same time the end of the copper plate surface in contact with the insulating layer It was confirmed that a resin flow (resin swell) occurred in the part (see FIG. 13). On the other hand, in Examples 1-6, the flow of resin or the sinking of the copper foil layer was not confirmed, and there was no problem.

2) Adhesive strength between insulating layer and copper foil layer (or copper plate layer) Each metal-clad laminate produced in Comparative Examples 1 to 4 is left in a hot air oven preset at 300 ° C. for 20 minutes, then taken out and placed in a room temperature environment. By rapidly cooling, the thermal shock during chip mounting was simulated. After the treatment, as shown in FIG. 14 (a), the insulating layer and the copper plate layer were peeled off and the adhesion was confirmed. As a result, in the metal-clad laminates of Comparative Examples 1 to 4, they were all easily peeled off. I was able to. Moreover, when the peeled-off insulating layer surface was visually observed as shown in FIG.14 (b), in Comparative Examples 1-3, the discoloration of the adhesive surface by the side of the insulating layer considered to be a crimping nonuniformity was confirmed. Moreover, the peeling considered to be caused by insufficient crimping of the copper plate end portion on the large size copper plate layer side was confirmed.

  In Examples 1-6, since the thermal history at the time of soldering in the manufacturing process of each metal-clad laminate can simulate a thermal shock at the time of chip mounting, the insulating layer and the copper foil layer in the obtained metal-clad laminate The adhesion with the (or copper plate layer) was evaluated. In each of the metal-clad laminates of Examples 1 to 6, it was difficult to peel off the insulating layer and the copper foil layer (or copper plate layer), and the peeled surface was a solder joint. That is, in Examples 1-6, it was confirmed that the adhesiveness of an insulating layer and a copper foil layer (or copper plate layer) is very strong.

  As mentioned above, although embodiment of this invention was described in detail for the purpose of illustration, this invention is not restrict | limited to the said embodiment. Those skilled in the art can make many modifications without departing from the spirit and scope of the present invention, and these are also included within the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Semiconductor element, 3 ... Laminated structure, 17 ... Joining layer, 21 ... Lead frame, 23 ... Joining layer, 25 ... Metal foil layer, 27 ... Insulating resin adhesive layer, 29 ... Metal plate layer

Claims (8)

A laminated structure used for a semiconductor module,
A semiconductor element;
A lead frame for supporting the semiconductor element;
A metal foil layer joined to the lead frame in an electrically and thermally conductive manner;
An insulating resin adhesive layer adhered to the metal foil layer;
A heat transfer metal layer that mediates heat conduction to the heat radiating member, which is adhered to the insulating resin adhesive layer;
A laminated structure comprising:   The laminated structure according to claim 1, further comprising a metal bonding layer at a bonding portion between the lead frame and the metal foil layer.   The surface treatment layer is provided on the surface of the metal foil layer on the side in contact with the insulating resin adhesive layer and on the surface of the heat transfer metal layer on the side in contact with the insulating resin adhesive layer, respectively. Laminated structure.   The laminated structure according to any one of claims 1 to 3, wherein the metal foil layer, the insulating resin adhesive layer, and the heat transfer metal layer are processed from a double-sided metal-clad laminate.   The laminated structure according to any one of claims 1 to 4, wherein the insulating resin adhesive layer is formed of an epoxy resin film.   The laminated structure according to claim 5, wherein the epoxy resin film contains a thermally conductive filler. A method for manufacturing a laminated structure used in a semiconductor module,
Preparing a double-sided metal-clad laminate in which a metal foil and a heat transfer metal layer are laminated on the front and back surfaces of the insulating resin film, and partially removing the metal foil of the double-sided metal-clad laminate by etching; ,
Bonding a metal plate to be a lead frame to the remaining metal foil other than the portion removed by etching; and
A step of further joining a semiconductor element to the outside of the metal plate to be the lead frame;
The manufacturing method of the laminated structure provided with.   The method for manufacturing a laminated structure according to claim 6 or 7, wherein the joining step is performed by soldering or a metal-based adhesive.

Images