Bonding sheet, semiconductor module, and method for manufacturing bonding sheet

Abstract

The adhesive sheet of the present application is an adhesive sheet having a sheet of dissimilar material coplanar with other portions.

Description

[0001] Cross Reference to Related Applications

[0002] This application claims priority to Japanese Patent Application No. 2020-141744, the contents of which are incorporated into this application by reference. TECHNICAL FIELD

[0003] The present application relates to a bonding sheet, a semiconductor module, and a method for manufacturing a bonding sheet. BACKGROUND

[0004] Conventionally, a semiconductor module in which a lead frame or the like on which a semiconductor element is mounted is resin-molded has been widely used.

[0005] In this semiconductor module, the following heat dissipation countermeasure is implemented: the lead frame is constituted by a thick metal plate, heat emitted from the semiconductor element mounted on the metal plate is thermally conducted to the metal plate side, and further, the heat is diffused to the outside of the module through a heat sink.

[0006] For such a semiconductor module, the heat sink is generally made of a metal such as aluminum or copper and is in a state of being exposed to the outside. Therefore, for the purpose of ensuring safety, an electrically insulating layer or the like is formed between the semiconductor element and the heat sink.

[0007] Regarding such a semiconductor module, for example, a semiconductor module having a semiconductor element, a lead frame bonded to a lower surface of the semiconductor element, a heat sink disposed further below the lead frame, and an electrically insulating layer formed between the heat sink and the lead frame is described in Patent Literature 1.

[0008] PRIOR ART DOCUMENTS

[0009] Patent Literature 1: Japanese Patent Application Publication No. 2013-30649 SUMMARY

[0010] PROBLEMS TO BE SOLVED BY THE INVENTION

[0011] The electrically insulating layer of the aforementioned semiconductor module is formed by a bonding sheet composed of a bonding resin composition containing an inorganic filler.

[0012] The bonding sheet for forming the electrically insulating layer can be used not only singly but also in a stacked state of two or more pieces.

[0013] In this regard, for example, in consideration of the possibility of defects such as voids and cracks in the bonding sheet, the following processing or the like is performed: two or more pieces of the bonding sheet are stacked to form an electrically insulating layer with high reliability of electrical insulation.

[0014] On the other hand, in order to make the adhesive sheet function differently from the function of the adhesive resin composition, a sheet main body composed of the adhesive resin composition is considered, and a dissimilar material sheet composed of a material different from the adhesive resin composition is also provided.

[0015] Then, as long as the dissimilar material sheet is formed to be smaller in area than the sheet main body and is laminated to the surface of the sheet main body, at least a part of both surfaces of the adhesive sheet is composed of the adhesive resin composition, and the adhesiveness from the adhesive resin composition can be exerted.

[0016] In addition, by exposing the surface of the dissimilar material sheet on one adhesive surface of the adhesive sheet, the adhesive surface exerts the adhesiveness from the adhesive resin composition, and a different function based on the dissimilar material sheet is exerted.

[0017] In this way, the adhesive sheet can be used for various purposes by various combinations of the adhesive resin composition and the dissimilar material sheet.

[0018] However, if the dissimilar material sheet protrudes in the thickness direction of the adhesive sheet to create a height difference at the outer periphery of the dissimilar material sheet, air is easily entrapped at the portion where the height difference is created when the adhesive sheet is adhered.

[0019] Therefore, if the dissimilar material sheet is provided on the adhesive sheet to exert various functions, there is a problem that air is easily entrapped when adhered.

[0020] In particular, in the semiconductor module, if air is entrapped when the electrically insulating layer is formed, there is a problem that a void is generated.

[0021] Solution to the problem

[0022] The present application provides an adhesive sheet having a first adhesive surface and a second adhesive surface opposite to the first adhesive surface as adhesive surfaces to be adhered to an adherend, the adhesive sheet having a sheet main body composed of an adhesive resin composition, the adhesive sheet further having a dissimilar material sheet composed of a material different from the adhesive resin composition, the dissimilar material sheet being thinner in thickness than the sheet main body and smaller in area than the sheet main body, the dissimilar material sheet being embedded in the sheet main body in a manner of being exposed on the first adhesive surface, the first adhesive surface having a first region composed of the adhesive resin composition and a second region composed of the material different from the adhesive resin composition,

[0023] The second region is coplanar with the first region.

[0024] Further, the present application provides a semiconductor module in order to solve the problem, which has a semiconductor element, a metal plate arranged below the semiconductor element and transferring heat emitted from the semiconductor element, a heat sink arranged below the metal plate and transferring the heat from the metal plate, and a resin mold covering the semiconductor element and the metal plate, and further has an electrically insulating layer between the heat sink and the metal plate, at least a part of the electrically insulating layer being composed of the above-mentioned bonding sheet.

[0025] Further, the present application provides a manufacturing method of a bonding sheet in order to solve the problem, which includes the steps of: a step of manufacturing a sheet in a first state having a double-layer structure in which one side is composed of a copper foil and the other side is composed of an adhesive resin composition; a step of manufacturing a sheet in a second state by removing a part of the copper foil from the sheet in the first state, in which a first region in which the adhesive resin composition is exposed and a second region in which the copper foil remains are formed on the one side; and a step of manufacturing a bonding sheet by making the second region coplanar with the first region by hot stamping the sheet in the second state. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a schematic front view showing the structure of a semiconductor module.

[0027] Figure 2 is a schematic top view showing the structure of a semiconductor module.

[0028] Figure 3 is a schematic sectional view showing the structure of a semiconductor module. Specifically, Figure 2 is a sectional view taken along line A-A' in FIG.

[0029] Figure 4 is a schematic top view showing the use of a bonding sheet. DETAILED DESCRIPTION

[0030] Hereinafter, a preferred embodiment of the present application will be described with reference to the accompanying drawings.

[0031] First, a semiconductor module will be described.

[0032] Figure 1 is a schematic front view of a semiconductor module of the present embodiment, Figure 2 is a schematic top view of the same semiconductor module.

[0033] Further, Figure 3 is a schematic sectional view showing the internal structure of a semiconductor module of the present embodiment, and is Figure 2 is a sectional view taken along line A-A' in FIG.

[0034] As shown in the figure, the semiconductor module of the present embodiment is a flat box type.

[0035] The semiconductor module of the present embodiment is rectangular in plan view.

[0036] The semiconductor module of the present embodiment is oblong in plan view.

[0037] With regard to the semiconductor module, six terminals protrude upward on the top surface side, and a plurality of tabs protrude downward on the bottom surface side.

[0038] Further, in the following, the Figure 1 , 3 The front view "longitudinal direction" is explained as the "up-down direction" of the semiconductor module in the present embodiment, and sometimes the "up-down direction" is referred to as the "vertical direction" or the "thickness direction".

[0039] Further, in the following, the direction orthogonal to the "vertical direction" is referred to as the "horizontal direction" or the "planar direction", and sometimes the Figure 1 , 3 The front view "transverse direction" is referred to as the "left-right direction".

[0040] Further, in the following, sometimes the Figure 2 The front view "longitudinal direction" is referred to as the "length direction" of the semiconductor module, the Figure 2 The front view "transverse direction" is referred to as the "width direction" of the semiconductor module, and so on.

[0041] The semiconductor module 100 of the present embodiment has three semiconductor elements 10 at positions that become the central portion in the thickness direction and the central portion in the width direction.

[0042] The semiconductor elements 10 are arranged at intervals from each other in the length direction of the semiconductor module.

[0043] Further, the semiconductor module 100 of the present embodiment has a lead member 20 that is a metal plate that conducts heat emitted from the semiconductor elements 10 and that becomes a conductive path that conducts electricity to the semiconductor elements 10.

[0044] Further, the semiconductor module 100 of the present embodiment has a heat sink 30 that conducts the heat from the lead member 20 below the lead member 20.

[0045] Further, the semiconductor module 100 has an electrically insulating layer 40 formed by an adhesive sheet between the heat sink and the metal plate.

[0046] The lead member 20 of the present embodiment has a shape in which a metal member that is a long plate is bent at a right angle halfway in the long direction.

[0047] The lead member 20 of this embodiment has a horizontal portion 21 arranged in a substantially horizontal direction with respect to the board surface within the semiconductor module, and a vertical portion 22 vertically extending upward from one end of the horizontal portion 21, an upper end portion of the vertical portion 22 constituting the terminal.

[0048] The semiconductor module 100 of this embodiment is provided with the horizontal portion 21 below the semiconductor element 10, an upper surface 21a of the horizontal portion 21 being bonded to a lower surface 10b of the semiconductor element 10.

[0049] In the semiconductor module 100 of this embodiment, at the bonding site, the lead member 20 and the semiconductor element 10 are electrically connected.

[0050] In addition, the semiconductor module 100 of this embodiment has another lead member 20' in addition to the lead member 20 on which the semiconductor element 10 is mounted on the upper surface of the horizontal portion thereof.

[0051] Hereinafter, the lead member 20 on which the semiconductor element 10 is mounted will be referred to as "first lead member", and the other lead member 20' will be referred to as "second lead member".

[0052] The second lead member 20' has a horizontal portion 21' and a vertical portion 22' like the first lead member 20, the horizontal portion 21' being electrically connected to the semiconductor element 10 by a solder wire 60, the upper end portion of the vertical portion 22' being included in the semiconductor module 100 in a state where it forms a terminal different from that of the first lead member 20.

[0053] Further, in the semiconductor module 100 of this embodiment, a lower surface 21b of the horizontal portion 21 of the first lead member 20 and a lower surface 21b' of the horizontal portion 21' of the second lead member 20' are bonded to an upper surface 40a of the electrically insulating layer 40, a lower surface 40b of the electrically insulating layer 40 being bonded to an upper surface 30a of the heat sink 30.

[0054] Thus, the heat sink 30 of this embodiment has a plate-shaped base portion 31 whose upper surface side is bonded to the lower surface 40b of the electrically insulating layer 40, and a tab portion 32 having a plurality of tabs extending downward from a lower surface of the base portion 31.

[0055] In addition, in the semiconductor module 100 of this embodiment, a resin mold 50 is formed on the upper side of the upper surface 40a of the electrically insulating layer 40 in a manner so as to cover the semiconductor element 10, the first lead member 20, and the second lead member 20'.

[0056] Therefore, the portion of the upper surface 40a of the electrically insulating layer 40 other than the region to which the first lead member 20 and the second lead member 20' are bonded is bonded to the lower surface 50b of the resin mold 50.

[0057] An electrically insulating layer 40 is formed by laminating two adhesive sheets 1, 1x having the same shape in plan view in the thickness direction. Figure 4 (Outline plan view) as shown in FIG. 1.

[0058] That is, the electrically insulating layer 40 is formed by laminating two adhesive sheets 1, 1x having the same shape in plan view in the thickness direction with the end edges thereof aligned, and has a two-layer laminated structure.

[0059] One of the two adhesive sheets 1 (hereinafter also referred to as "first adhesive sheet") and the other adhesive sheet 1x (hereinafter also referred to as "second adhesive sheet") have both faces thereof as adhesive faces.

[0060] In the electrically insulating layer 40, the first adhesive sheet 1 constitutes the lower layer side, and the second adhesive sheet 1x constitutes the upper layer side of the electrically insulating layer 40.

[0061] The first adhesive sheet 1 of the present embodiment is interposed between the second adhesive sheet 1x and the heat sink 30 (substrate portion 31), and the second adhesive sheet 1x of the present embodiment is interposed between the first adhesive sheet 1 and the lead member 20, 20'.

[0062] In the first adhesive sheet 1, the upper surface side bonded to the second adhesive sheet 1x as an adherend becomes a first adhesive face 1a, and the lower surface side as the opposite face of the first adhesive face 1a becomes a second adhesive face 1b bonded to the upper surface of the substrate portion 31 of the heat sink 30.

[0063] On the other hand, in the second adhesive sheet 1x, the upper surface side bonded to the lead member 20, 20' and the like as an adherend becomes a first adhesive face 1xa, and the lower surface side as the opposite face of the first adhesive face 1xa becomes a second adhesive face 1xb bonded to the first adhesive face 1a of the first adhesive sheet 1.

[0064] The first adhesive sheet 1 has a sheet main body 11 composed of an adhesive resin composition, and further has a dissimilar material sheet 12 composed of a material different from the adhesive resin composition, which is thinner in thickness and smaller in area than the sheet main body 11.

[0065] In the first adhesive sheet 1, the foreign material sheet 12 is embedded in the sheet main body 11 in a manner exposed at the first adhesive surface la having the first region la 1 composed of the adhesive resin composition and the second region la2 composed of the material different from the adhesive resin composition.

[0066] The second region la2 of the first adhesive sheet 1 is coplanar with the first region la 1, and no height difference is formed at the boundary between the first region la 1 and the second region la2.

[0067] The first adhesive surface la of the first adhesive sheet 1 is composed of two materials different in properties, and the second adhesive surface lb is composed only of the adhesive resin composition constituting the sheet main body 11.

[0068] The second adhesive sheet lx of the present embodiment is composed only of the adhesive resin composition, and does not have the foreign material sheet 12.

[0069] Therefore, the first adhesive surface laxa and the second adhesive surface lb of the second adhesive sheet lx are composed only of the adhesive resin composition, like the second adhesive surface lb of the first adhesive sheet 1.

[0070] Further, the second region la2 of the first adhesive sheet 1 is provided at a central portion of the first adhesive surface la, and is completely surrounded by the first region la 1.

[0071] Therefore, the foreign material sheet 12 of the present embodiment is composed of the adhesive resin composition in a state embedded in the adhesive resin composition, and constitutes the electrically insulating layer 40 together with the adhesive resin composition.

[0072] Then, the electrically insulating layer 40 exhibits different properties by more strongly reflecting the properties of the central portion of the foreign material sheet 12 and the properties of the outer peripheral portion hardly affected by the foreign material sheet 12.

[0073] Here, the resin mold 50 can be formed by a method such as casting molding of the resin composition in a heated and molten state, like a conventional semiconductor module.

[0074] In this case, the outer peripheral portion of the electrically insulating layer 40 is more strongly subjected to a force in the thickness direction stretched than the central portion due to the curing shrinkage of the resin mold 50.

[0075] Further, the stress generated at the interface between the resin mold 50 and the electrically insulating layer 40 and the stress generated at the interface between the heat sink 30 and the electrically insulating layer 40 due to the difference in the thermal expansion coefficient between the resin mold 50 and the heat sink 30, and the difference in the temperature between the operation and the rest of the semiconductor module 100, and the like also similarly act more strongly on the outer peripheral portion than the central portion.

[0076] The outer peripheral portion of the electrically insulating layer 40 of the present embodiment is formed only of the adhesive resin composition, and thus, a strong resistance against the stress as described above can be exerted.

[0077] Since the dissimilar material sheet 12 is present in the central portion of the electrically insulating layer 40, the possibility of interface peeling is higher than that of the outer peripheral portion, but various characteristics different from those of the outer peripheral portion can be easily exerted by the dissimilar material sheet.

[0078] Further, in the electrically insulating layer 40, since there is no height difference around the dissimilar material sheet 12 when the first adhesive sheet 1 and the second adhesive sheet 1x are laminated, the entrapment of air can be suppressed, and the formation of voids can also be suppressed.

[0079] The adhesive resin composition used for forming the electrically insulating layer 40 as described above is preferably excellent in electrically insulating properties, and preferably has a volume resistivity of 1 x 10 13 Ω·cm or more.

[0080] The volume resistivity of the adhesive resin composition is usually 1 x 10 18 Ω·cm or less.

[0081] The volume resistivity can be measured, for example, by the method prescribed in JIS C2139, and the volume resistivity can be obtained by performing the measurement as described above on a sheet made using the adhesive resin composition.

[0082] In terms of exerting excellent thermal conductivity by the electrically insulating layer 40, the adhesive resin composition preferably contains, in addition to a resin, an inorganic filler having a higher thermal conductivity than the resin.

[0083] The resin contained in the adhesive resin composition of the present embodiment is not particularly limited, and can be a thermoplastic resin or a thermosetting resin.

[0084] As the thermoplastic resin, polyethylene resin, polypropylene resin, ethylene-vinyl acetate copolymer resin, polyvinyl chloride resin, polystyrene resin, phenoxy resin, acrylic resin, polyamide resin, polyamide-imide resin, polyimide resin, polyether-imide resin, polyether-sulfide resin, polyphenylene-sulfide resin, polyether-imide resin, thermoplastic elastomer, and the like can be exemplified.

[0085] In addition, if the thermosetting resin is used, epoxy resin, phenol resin, unsaturated polyester resin, and the like can be exemplified.

[0086] Among the above exemplified resins, as for the thermoplastic resin, most of the resins cannot exert high adhesive force alone.

[0087] Therefore, in the case where the adhesive resin composition contains a thermoplastic resin, it is also possible to contain a tackifier or the like as a tackiness imparting agent.

[0088] Among the above resins, an epoxy resin is preferred because it can exhibit high adhesiveness even without containing a tackifier or the like and has high compatibility with inorganic fillers.

[0089] That is, the adhesive resin composition of the present embodiment is preferably an epoxy resin composition.

[0090] As the epoxy resin, for example, bisphenol-based epoxy resins such as bisphenol A type epoxy resins and bisphenol F type epoxy resins, and novolak type epoxy resins such as phenol novolak type epoxy resins and cresol novolak type epoxy resins can be exemplified.

[0091] The epoxy resin can also be a modified product subjected to CTBN modification or the like.

[0092] The epoxy resin can also be a high molecular weight type such as phenoxy resin or the like.

[0093] One of the above epoxy resins can be contained alone in the adhesive resin composition, or two or more kinds thereof can be contained.

[0094] A curing agent for curing the epoxy resin, a curing accelerator can also be contained in the adhesive resin composition.

[0095] As the curing agent, although there is no particular limitation, for example, amine-based curing agents such as diaminodiphenyl sulfone, dicyandiamide, diaminodiphenylmethane, triethylenetetramine, and the like; phenol-based curing agents such as phenol novolak resin, aralkyl type phenol resin, dicyclopentadiene-modified phenol resin, naphthalene type phenol resin, bisphenol-based phenol resin, and the like; acid anhydride; and the like can be used.

[0096] As the curing accelerator, although there is no particular limitation, imidazoles or amine-based curing accelerators such as triphenyl phosphate (TPP) and boron trifluoride monoethylamine can be used.

[0097] As for the curing agent and the curing accelerator, one of each can be contained alone in the adhesive resin composition, or two or more kinds of at least one of them can be contained in the adhesive resin composition.

[0098] As for the inorganic filler contained in the adhesive resin composition, an inorganic filler generally widely used for the purpose of imparting thermal conductivity to a resin product can be used, but boron nitride is preferred because it has excellent thermal conductivity.

[0099] Furthermore, a particle (agglomerated particle) in which a plurality of plate-like primary particles of boron nitride are aggregated and agglomerated is preferably used.

[0100] As the agglomerated particles, agglomerated particles formed in a state of integral particles (particulate particles), or agglomerated particles in a state of aggregates (aggregate particles), and the like can be used, wherein the state of aggregates refers to a state of aggregation to the extent that the scale-like structure of primary particles of boron nitride can be distinguished.

[0101] In terms of the electrically insulating layer 40 exerting excellent thermal conductivity, the adhesive resin composition preferably contains the epoxy resin and the inorganic filler as described above, and the content of the inorganic filler is preferably 50% by volume or more.

[0102] The content of the inorganic filler is more preferably 55% by volume or more, and particularly preferably 60% by volume or more.

[0103] In terms of the adhesive resin composition exerting excellent adhesiveness, the content of the inorganic filler in the adhesive resin composition is preferably 75% by volume or less, and more preferably 70% by volume or less.

[0104] In the adhesive resin composition, the proportion of the epoxy resin in the total resin contained is preferably 90% by mass or more, and more preferably 95% by mass or more, and particularly preferably substantially no resin other than the epoxy resin is contained.

[0105] In the adhesive resin composition, in addition to the above-described components, other substances generally used as rubber, plastic composite chemicals, such as dispersants, anti-aging agents, antioxidants, processing aids, stabilizers, defoaming agents, flame retardants, thickening agents, pigments, and the like can be appropriately contained.

[0106] Regarding the sheet of a different material used in common with the adhesive resin composition to form the electrically insulating layer 40, in the present embodiment, since the electrically insulating layer 40 is formed in a state of being embedded in the adhesive resin composition, it is not necessarily required to have electrical insulating properties, and can have electrical conductivity.

[0107] As the sheet of a different material, for example, a resin film, a rubber sheet, a metal film, and the like can be exemplified.

[0108] In addition, as the sheet of a different material, for example, a fiber sheet composed of various fibers such as resin fibers, carbon fibers, glass fibers, ceramic fibers, metal fibers, and the like can be exemplified.

[0109] Further, the sheet of a different material need not have flexibility, and can be a ceramic plate, a glass plate, a metal plate, and the like.

[0110] As effects that can be exerted by the sheet of different material on the adhesive sheet and the electrically insulating layer, there can be listed: effects related to mechanical properties such as bending / tensile strength, flexibility, etc.; effects related to thermal properties such as thermal decomposability, flame retardancy, etc.; effects related to electromagnetic properties such as dielectric properties, shielding properties, etc.

[0111] The thickness of the electrically insulating layer 40 is usually 10 μm or more and 1000 μm or less.

[0112] The thickness of the electrically insulating layer 40 is preferably 50 μm or more and 500 μm or less.

[0113] The thickness of the first adhesive sheet 1 and the second adhesive sheet lx is usually 5 μm or more and 500 μm or less, and is preferably 25 μm or more and 250 μm or less.

[0114] Further, the thickness of the first adhesive sheet 1 and the second adhesive sheet lx can be the same or different.

[0115] The thickness of the sheet of different material possessed by the first adhesive sheet 1 can be, for example, 1 μm or more and 200 μm or less.

[0116] The thickness of the sheet of different material is preferably 1 / 100 or more and 1 / 2 or less of the thickness of the first adhesive sheet 1, and is more preferably 1 / 10 or more and 1 / 3 or less.

[0117] The size (area) of the sheet of different material can be, for example, 10% or more and 80% or less of the area of the first adhesive sheet 1.

[0118] In terms of easily exerting excellent adhesiveness with respect to the adhesive resin composition, the sheet of different material is preferably an electrolytic copper foil.

[0119] An electrolytic copper foil has a flat side on the side that comes into contact with an electrolytic drum at the time of manufacture, and a side that comes into contact with an electrolytic solution has a concave-convex structure of several micrometers in height.

[0120] The flat side of an electrolytic copper foil is called a glossy side or a bright side, etc., and the side on which the concave-convex structure is observed is called a matte side, etc., and for the second region la2 of the first adhesive sheet 1, it is preferable to make it consist of a bright side in terms of difficulty in entrapping air between the second adhesive sheet lx.

[0121] That is, in the first adhesive sheet 1 of the present embodiment, it is preferable that the sheet of different material be an electrolytic copper foil having a matte side and a bright side, and the second region la2 be made to consist of the bright side of the electrolytic copper foil.

[0122] In the case where a copper foil is used as the sheet of different material, as a method of manufacturing the first adhesive sheet 1, it is preferable to use a method having the following steps.

[0123] a) a step of dispersing the adhesive resin composition in an organic solvent to prepare a coating liquid

[0124] b) a step of applying the coating liquid to one side of a copper foil and drying it to produce a first-state sheet having a double-layer structure in which one side is composed of the copper foil and the other side is composed of the adhesive resin composition

[0125] c) a step of removing a part of the copper foil from the first-state sheet to produce a second-state sheet in which a first region in which the adhesive resin composition is exposed and a second region in which the copper foil remains are formed on the one side

[0126] d) a step of producing an adhesive sheet by performing hot press molding on the second-state sheet so that the second region is coplanar with the first region

[0127] The above "a) step" can be performed using, for example, a homogenizer or a blender.

[0128] The above "b) step" can be performed using, for example, a gravure coater or a kiss coater, and a heating / drying oven.

[0129] The above "c) step" can be performed using, for example, an etching machine.

[0130] The above "d) step" can be performed using, for example, a vacuum hot press machine.

[0131] In the case where an epoxy resin composition is used as the adhesive resin composition, the amount of heat to be applied is preferably adjusted or the like in this "d) step" to adjust the degree of curing of the epoxy resin composition.

[0132] In the above production method, the desired adhesive sheet can be produced simply.

[0133] Further, in the adhesive sheet produced by the above production method, the difference in level around the copper foil on the side where the copper foil is exposed is eliminated in the "d) step", and thus the occurrence of air bubbles due to the difference in level at the time of bonding can be prevented.

[0134] In addition, in the above examples, the embodiments of the present application are exemplified in the case where the electrically insulating layer of the semiconductor module is configured by overlapping the adhesive sheet having the dissimilar material sheet and the adhesive sheet not having the dissimilar material sheet, but the use form of the adhesive sheet of the present application is not limited to this case.

[0135] For example, the electrically insulating layer can be formed by only one adhesive sheet having the dissimilar material sheet, or can be formed by laminating a plurality of adhesive sheets having the dissimilar material sheet.

[0136] In addition, the adhesive sheet of the present application is not used only for forming an electrically insulating layer of a semiconductor module, and the use thereof is not particularly limited.

[0137] In addition, the present application is not limited to the above-described examples.

[0138] The matters disclosed in this specification include the following. (1)

[0140] An adhesive sheet having a first adhesive surface and a second adhesive surface opposite to the first adhesive surface as adhesive surfaces to be adhered to adherends,

[0141] The adhesive sheet has a sheet main body composed of an adhesive resin composition,

[0142] The adhesive sheet further has a dissimilar material sheet composed of a material different from the adhesive resin composition, having a thickness thinner than that of the sheet main body and an area smaller than that of the sheet main body,

[0143] The dissimilar material sheet is embedded in the sheet main body in a manner exposed on the first adhesive surface, and has a first region composed of the adhesive resin composition and a second region composed of the material different from the adhesive resin composition on the first adhesive surface,

[0144] The second region is coplanar with the first region.

[0145] In the adhesive sheet of the present embodiment, in the first adhesive surface of the adhesive sheet, the first region composed of the adhesive resin composition is coplanar with the second region composed of a material different from the adhesive resin composition.

[0146] In other words, the dissimilar material sheet composed of a material different from the adhesive resin composition is embedded in the first adhesive surface of the adhesive sheet in a manner coplanar with the first region composed of the adhesive resin composition.

[0147] Thus, it is possible to suppress the case where air is rolled in due to a height difference at the time of use of the adhesive sheet.

[0148] That is, the adhesive sheet of the present embodiment is less likely to roll in air at the time of adhesion. (2)

[0150] The adhesive sheet according to the above-described (1), wherein the adhesive resin composition contains an epoxy resin and an inorganic filler,

[0151] The inorganic filler is contained at a rate of 50% by volume or more.

[0152] According to this configuration, it is possible to cause the adhesive sheet to exhibit excellent thermal conductivity. (3)

[0154] The adhesive sheet according to (2) above, wherein the inorganic filler is contained at 75 vol% or less.

[0155] According to this configuration, the adhesive resin composition can exhibit excellent adhesion. (4)

[0157] The adhesive sheet according to any one of (1) to (3) above, wherein the dissimilar material sheet is an electrolytic copper foil having a matte surface and a bright surface,

[0158] The second region is constituted by the bright surface of the electrolytic copper foil.

[0159] According to this configuration, since the dissimilar material sheet is an electrolytic copper foil, the dissimilar material sheet can easily exhibit excellent adhesion with respect to the adhesive resin composition.

[0160] In addition, since the second region is constituted by the bright surface of the electrolytic copper foil, it is difficult for air to be entrapped between adherends when the adhesive sheet is used.

[0161] That is, it is possible to suppress the entrapping of air in the adhesive sheet due to a height difference when used. (5)

[0163] A semiconductor module having: a semiconductor element; a metal plate disposed below the semiconductor element and transmitting heat emitted from the semiconductor element; a heat sink disposed below the metal plate and receiving the heat transmitted from the metal plate; and a resin mold covering the semiconductor element and the metal plate,

[0164] An electrically insulating layer is further provided between the heat sink and the metal plate,

[0165] At least a portion of the electrically insulating layer is constituted by the adhesive sheet according to any one of (1) to (4) above.

[0166] According to this configuration, at least a portion of the electrically insulating layer is constituted by the adhesive sheet as described above, and therefore, in the semiconductor module, it is difficult for air to be entrapped when the heat sink and the metal plate are adhered.

[0167] Thus, the semiconductor module of the present embodiment has an electrically insulating layer with excellent insulation reliability. (6)

[0169] A method for manufacturing an adhesive sheet, comprising the steps of:

[0170] a step of producing a sheet in a first state having a double-layer structure in which one side is composed of a copper foil and the other side is composed of an adhesive resin composition;

[0171] a step of producing a sheet in a second state by removing a part of the copper foil from the sheet in the first state, in which a first region in which the adhesive resin composition is exposed and a second region in which the copper foil remains are formed on the one side; and

[0172] a step of producing an adhesive sheet by performing hot press molding on the sheet in the second state so that the second region is coplanar with the first region.

[0173] According to this configuration, an adhesive sheet having a first region in which the adhesive resin composition is exposed and a second region in which the copper foil remains can be easily produced.

[0174] In addition, the adhesive sheet obtained by the manufacturing method described above is difficult to entrap air when being bonded.

[0175] Note that the adhesive sheet, the semiconductor module, and the manufacturing method of the adhesive sheet of the present application are not limited to the above-described embodiments. In addition, the adhesive sheet, the semiconductor module, and the manufacturing method of the adhesive sheet of the present application are not limited by the above-described effects. The adhesive sheet, the semiconductor module, and the manufacturing method of the adhesive sheet of the present application can be variously changed within the scope of the gist of the present application.

[0176] Explanation of Reference Signs

[0177] 1 adhesive sheet

[0178] 1a first adhesive surface

[0179] 1a1 first region

[0180] 1a2 second region

[0181] 10 semiconductor element

[0182] 11 sheet body

[0183] 12 dissimilar material sheet

[0184] 20 lead member (metal plate)

[0185] 30 heat sink

[0186] 40 electrically insulating layer

[0187] 50 resin mold

Claims

1. An electrically insulating layer having a laminated structure of a first adhesive sheet and a second adhesive sheet, the first adhesive sheet and the second adhesive sheet each having a first adhesive surface and a second adhesive surface opposite to the first adhesive surface as an adhesive surface to be adhered to an adherend, the first adhesive sheet having a sheet main body composed of an adhesive resin composition, the adhesive resin composition containing an epoxy resin and an inorganic filler, and the inorganic filler being contained at a rate of 50% by volume or more, the first adhesive sheet further having a dissimilar material sheet composed of a material different from the adhesive resin composition, having a thickness thinner than that of the sheet main body, and having an area smaller than that of the sheet main body, the thickness of the dissimilar material sheet being 1 / 2 or less of the thickness of the first adhesive sheet, the dissimilar material sheet being embedded in the sheet main body in a manner to be exposed at the first adhesive surface, the first adhesive surface having a first region composed of the adhesive resin composition and a second region composed of the material different from the adhesive resin composition, the second region being coplanar with the first region, a height difference not being formed at a boundary between the first region and the second region, the dissimilar material sheet being an electrolytic copper foil having a matte surface and a bright surface, the second region being composed of the bright surface of the electrolytic copper foil, the second adhesive sheet being in contact with the first adhesive surface of the first adhesive sheet, and being composed only of the adhesive resin composition containing an epoxy resin and an inorganic filler.

2. A semiconductor module having: a semiconductor element; a metal plate disposed below the semiconductor element and transferring heat emitted by the semiconductor element; and a heat sink disposed below the metal plate and receiving the heat transferred from the metal plate. a resin mold covering the semiconductor element and the metal plate; and an electrically insulating layer disposed between the heat sink and the metal plate, the electrically insulating layer being composed of the electrically insulating layer according to claim 1.

2. The electrically insulating layer according to claim 1, wherein the first adhesive sheet further has a third adhesive sheet composed of the adhesive resin composition, the third adhesive sheet being disposed on the second adhesive surface of the first adhesive sheet.

3. The electrically insulating layer according to claim 1 or 2, wherein the first adhesive sheet further has a fourth adhesive sheet composed of the adhesive resin composition, the fourth adhesive sheet being disposed on the second adhesive surface of the second adhesive sheet.

4. The electrically insulating layer according to any one of claims 1 to 3, wherein the first adhesive sheet further has a fifth adhesive sheet composed of the adhesive resin composition, the fifth adhesive sheet being disposed on the second adhesive surface of the third adhesive sheet.

5. The electrically insulating layer according to any one of claims 1 to 4, wherein the first adhesive sheet further has a sixth adhesive sheet composed of the adhesive resin composition, the sixth adhesive sheet being disposed on the second adhesive surface of the fourth adhesive sheet.

6. The electrically insulating layer according to any one of claims 1 to 5, wherein the first adhesive sheet further has a seventh adhesive sheet composed of the adhesive resin composition, the seventh adhesive sheet being disposed on the second adhesive surface of the fifth adhesive sheet.

7. The electrically insulating layer according to any one of claims 1 to 6, wherein the first adhesive sheet further has an eighth adhesive sheet composed of the adhesive resin composition, the eighth adhesive sheet being disposed on the second adhesive surface of the sixth adhesive sheet.

8. The electrically insulating layer according to any one of claims 1 to 7, wherein the first adhesive sheet further has a ninth adhesive sheet composed of the adhesive resin composition, the ninth adhesive sheet being disposed on the second adhesive surface of the seventh adhesive sheet.

9. The electrically insulating layer according to any one of claims 1 to 8, wherein the first adhesive sheet further has a tenth adhesive sheet composed of the adhesive resin composition, the tenth adhesive sheet being disposed on the second adhesive surface of the eighth adhesive sheet.

10. The electrically insulating layer according to any one of claims 1 to 9, wherein the first adhesive sheet further has an eleventh adhesive sheet composed of the adhesive resin composition, the eleventh adhesive sheet being disposed on the second adhesive surface of the ninth adhesive sheet.

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