Semiconductor encapsulation resin composition and semiconductor device

Abstract

To provide a resin composition that realizes a highly reliable semiconductor device.SOLUTION: A semiconductor device includes: a resin composition for sealing a semiconductor containing one or more epoxy resin main agents selected from alicyclic epoxy and aliphatic epoxy containing two or more aromatic rings, a hardener having a diaminodiphenyl backbone, and an inorganic filler; and a sealing layer 20 in contact with conductive plates 121, 123 and a conductive connecting member 18 to include the resin composition for sealing the semiconductor.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a resin composition for semiconductor encapsulation and a semiconductor device. In particular, the present invention relates to a resin composition for semiconductor encapsulation that can improve adhesion between an encapsulating layer and a metal member constituting a semiconductor device, and a highly reliable semiconductor device using the same. [Background technology]

[0002] Power semiconductor modules are widely used in fields that require efficient power conversion. For example, their application is expanding to power electronics fields such as industrial equipment, electric vehicles, and home appliances. These power semiconductor modules contain switching elements and diodes, and the elements are made of silicon (Si) semiconductors or silicon carbide (SiC) semiconductors. Power semiconductor modules are manufactured by sealing chips made of semiconductor elements and conductive connection members such as lead frames connected to the chips with an insulating sealing material.

[0003] A curable epoxy resin composition that improves the durability of an optical semiconductor device is known, which is characterized by containing a cyclic epoxy compound, an isocyanuric acid derivative having one or more oxirane rings in the molecule, and an oxetane compound having one or more oxetane rings in the molecule (see, for example, Patent Document 1).

[0004] 2. Description of the Related Art Curable resin compositions suitable for optical materials are known, which contain an epoxy resin having an epoxycyclohexane structure and an alcohol having a tricyclodecane structure (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2019-023316 [Patent Document 2] Patent Publication No. 2011-246531 Summary of the Invention [Problem to be solved by the invention]

[0006] When a thermosetting resin is used as an encapsulation layer, the adhesion between the metal members constituting the semiconductor device and the thermosetting resin greatly affects the reliability of the semiconductor device. In particular, in a power semiconductor module with high dielectric strength, peeling of the thermosetting resin occurs at a location with low adhesion, which may become the starting point of dielectric breakdown and cause a decrease in the withstand voltage. In the method disclosed in the prior art, various resin compositions are disclosed for use in optical semiconductor devices. There is a demand for a resin composition for semiconductor encapsulation that has excellent withstand voltage characteristics and a more reliable encapsulation function. [Means for solving the problem]

[0007] As a result of extensive research, the inventors have come up with the idea of ​​ensuring high adhesion between metal and thermosetting resin by using a resin composition containing a specific epoxy resin base and a curing agent as components, and have also found that this composition reduces the elastic modulus of the resin after curing, thereby completing the present invention.

[0008] That is, according to one embodiment, the present invention relates to a resin composition for semiconductor encapsulation, comprising one or more epoxy resin base agents selected from alicyclic epoxies and aliphatic epoxies containing two or more aromatic rings, a curing agent having a diaminodiphenyl skeleton, and an inorganic filler.

[0009] In the semiconductor encapsulating resin composition, the curing agent having a diaminodiphenyl skeleton is preferably selected from 4,4'-diaminodiphenylmethane and 4,4'-diaminodiphenylsulfone.

[0010] In the semiconductor encapsulating resin composition, the alicyclic epoxy is preferably an alicyclic epoxy having two or more alicyclic epoxy groups in one molecule.

[0011] In the semiconductor encapsulating resin composition, the epoxy resin base preferably contains an alicyclic epoxy and an aliphatic epoxy containing two or more aromatic rings.

[0012] In the semiconductor encapsulating resin composition, the alicyclic epoxy is preferably contained in an amount of 50% by volume or more based on the total volume of the epoxy resin base material.

[0013] According to another embodiment of the present invention, there is provided a semiconductor device, comprising: A semiconductor element mounted on a laminated substrate including an insulating substrate and a conductive plate; A conductive connection member; a sealing layer that seals the semiconductor element and the conductive connection member; Equipped with The present invention relates to a semiconductor device, wherein the sealing layer is in contact with the conductive plate and the conductive connecting member and contains the semiconductor sealing resin composition according to claim 1.

[0014] According to another embodiment of the present invention, a semiconductor device mounted on a laminated substrate having an insulating substrate and a conductive plate; A conductive connection member; a sealing layer that seals the semiconductor element and the conductive connection member; A method for reducing an elastic modulus of the sealing layer at an interface between the conductive plate and the conductive connection member and improving adhesion of the sealing layer in a semiconductor device comprising the steps of: The present invention relates to a method comprising the steps of placing the semiconductor encapsulating resin composition according to claim 1 in contact with the conductive plate and the conductive connecting member, and curing the composition. Effect of the Invention

[0015] According to the present invention, it is possible to provide a resin composition for semiconductor encapsulation, which can improve the adhesion between a metal member and an encapsulating layer and reduce the elastic modulus of the encapsulating layer at the interface with the metal, thereby providing a highly reliable semiconductor device. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a conceptual cross-sectional view showing the structure of a semiconductor device according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. However, the present invention is not limited to the embodiment described below.

[0018] [First embodiment: resin composition] According to a first embodiment, the present invention relates to a resin composition for semiconductor encapsulation. The resin composition for semiconductor encapsulation according to this embodiment includes an epoxy resin base, a curing agent, and an inorganic filler. The resin composition for semiconductor encapsulation refers to a resin composition used for insulating and sealing a metal member included as a component of a semiconductor device. The semiconductor device is preferably a power semiconductor module, and may be, for example, a power semiconductor module for vehicle use. Hereinafter, in this specification, the resin composition for semiconductor encapsulation may be abbreviated to the resin composition.

[0019] The epoxy resin base is one or more compounds selected from aliphatic epoxies containing two or more aromatic rings and alicyclic epoxies.

[0020] An aliphatic epoxy resin containing two or more aromatic rings is an epoxy compound in which the carbon to which the epoxy group is directly bonded is a carbon that constitutes an aliphatic hydrocarbon, and the main chain contains two or more aromatic rings. Examples of such aliphatic epoxy resins include, but are not limited to, bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AD ​​type epoxy resins, biphenyl type epoxy resins, naphthalene type epoxy resins, and cresol novolac type epoxy resins. These can be used alone or in combination of two or more types.

[0021] Alicyclic epoxy refers to an epoxy compound having an alicyclic epoxy group, in which two carbon atoms constituting the epoxy group constitute an alicyclic compound. Examples of alicyclic epoxy resins include, but are not limited to, monofunctional epoxy resins, bifunctional epoxy resins, and polyfunctional epoxy resins having three or more functional groups. In particular, compounds containing two or more alicyclic epoxy groups in one molecule are preferred. For example, an oligomer type epoxy obtained by linearly polymerizing a monomer containing one alicyclic epoxy group, or an oligomer type epoxy obtained by bonding a plurality of linear polymers containing one alicyclic epoxy group at one end to the other end, can be used. The alicyclic epoxy resin can also be used alone, or two or more different alicyclic epoxy resins can be used in combination. In addition, a structure having a cycloalkene oxide such as cyclohexene oxide is often used as the alicyclic epoxy group.

[0022] The epoxy resin base may be a mixture of the above-mentioned aliphatic epoxy and alicyclic epoxy. The mixing ratio when mixing may be arbitrary, but the volume ratio of the alicyclic epoxy to the total volume of the bases of the aliphatic epoxy and alicyclic epoxy is preferably 50% or more. This is because by including 50% or more of the alicyclic epoxy in the epoxy resin base, higher adhesion and lower elastic modulus can be realized.

[0023] The curing agent used is an amine-based curing agent having a diaminodiphenyl skeleton (diaminodiphenyl-based curing agent). The amine-based curing agent having a diaminodiphenyl skeleton is a compound having a structure represented by the following formula. [ka] In the formula, X is a divalent group, and may be, for example, but is not limited to, CH2, SO2, O, S, N(C=O), or paraphenylene. X is particularly preferably CH2 or SO2, and more preferably CH2.

[0024] The amount of the curing agent is preferably about 40 to 110 parts by volume, more preferably about 50 to 100 parts by volume, per 100 parts by volume of the epoxy resin base. If the amount of the curing agent is less than 40 parts by volume, the glass transition temperature may decrease due to insufficient crosslinking, and if it is more than 110 parts by volume, the moisture resistance, high heat distortion temperature, and heat resistance stability may decrease.

[0025] The inorganic filler may be a metal oxide or a metal nitride, and examples thereof include, but are not limited to, silica (silicon oxide), alumina, aluminum hydroxide, titania, zirconia, aluminum nitride, talc, clay, mica, and glass fiber. These inorganic fillers may be used alone, or two or more may be mixed together. The inorganic filler may be a microfiller or a nanofiller, and two or more inorganic fillers having different particle sizes and / or types may be mixed together. In particular, it is preferable to use an inorganic filler having an average particle size of about 0.2 to 20 μm. The amount of inorganic filler added in the resin composition is preferably 100 to 600 parts by mass, and more preferably 200 to 400 parts by mass, when the total mass of the thermosetting resin base agent and the curing agent is 100 parts by mass. If the amount of inorganic filler is less than 100 parts by mass, the thermal expansion coefficient of the resin obtained by curing the resin composition may be high, and peeling or cracking may easily occur. If the blend amount is more than 600 parts by mass, the viscosity of the composition increases, which may result in poor extrusion moldability.

[0026] A curing accelerator can be added to the resin composition as an optional component. As the curing accelerator, imidazole or its derivative, tertiary amine, boric acid ester, Lewis acid, organometallic compound, organic acid metal salt, etc. can be appropriately blended. The amount of the curing accelerator added is preferably 0.01 parts by mass or more and 50 parts by mass or less, more preferably 0.1 parts by mass or more and 20 parts by mass or less, based on 100 parts by mass of the epoxy resin base material.

[0027] The resin composition may also contain optional additives to the extent that the properties of the resin composition are not impaired. Examples of additives include, but are not limited to, flame retardants, pigments for coloring the resin, and plasticizers and silicone elastomers for improving crack resistance. These optional components and the amounts of the additives can be appropriately determined by those skilled in the art according to the specifications required for the semiconductor device and / or the encapsulant.

[0028] As a kind of additive for resin compositions, it is known that a silane coupling agent is used to improve the adhesion between resin and metal. The resin composition according to the present embodiment may contain a silane coupling agent. However, the resin composition according to the present embodiment can achieve high adhesion without using a silane coupling agent by using the above-mentioned specific epoxy resin base agent and curing agent in combination, and can obtain a high level of adhesion that could not be achieved by the silane coupling agent.

[0029] The resin composition according to the first embodiment can be obtained by mixing the above-mentioned components by a conventional method.

[0030] The resin composition according to the first embodiment has high adhesion to a metal member mainly composed of a metal capable of forming a natural oxide film on the surface, such as nickel (Ni), copper (Cu), aluminum (Al), silver (Ag), or an alloy containing these metals, by contacting the resin composition with the metal member and curing the resin composition by heating. Examples of the alloy include, but are not limited to, brass (an alloy containing Cu and Zn) and an alloy containing tin (Sn) such as a solder material. The main component of the metal member refers to a component contained in the metal member by 50 mass % or more. In addition, the elastic modulus of the cured product can be reduced at the interface between the metal member and the cured product obtained by curing the resin composition by heating. Due to these characteristics, the resin composition according to the first embodiment can be used for insulating and sealing a semiconductor device, and a semiconductor device including the resin composition according to the first embodiment as a resin constituting a sealing layer can obtain high reliability.

[0031] [Second embodiment: semiconductor device] According to a second embodiment, the present invention relates to a semiconductor device including an encapsulating layer, the encapsulating layer including the semiconductor encapsulating resin composition according to the first embodiment in contact with a conductive plate and a conductive connecting member.

[0032] 1 is a conceptual cross-sectional view of a power semiconductor module, which is an example of a semiconductor device according to a second embodiment. The illustrated power semiconductor module has a laminated structure in which a semiconductor element 11 and a laminated substrate 12 are bonded onto a heat sink 13 by a bonding layer 17. A case 16 incorporating an external terminal 15 is attached to the heat sink 13. The electrodes of the semiconductor element 11 and the laminated substrate 12 are connected by a lead frame 18, which is a conductive connecting member. The semiconductor element 11 and the external terminal 15 are also connected by an aluminum wire 14. A sealant that comes into contact with and covers the semiconductor element 11, the laminated substrate 12, the lead frame 18, and the aluminum wire 14, which is a conductive connecting member, is filled in the space defined by the case 16 and the heat sink 13, forming a sealing layer 20.

[0033] The semiconductor element 11 is a power chip such as an IGBT (Insulated Gate Bipolar Transistor) or a diode chip, and may be a Si device or a wide-gap semiconductor device such as a SiC device, a GaN device, a diamond device, or a ZnO device. These devices may be used in combination. For example, a hybrid module using a Si-IGBT and a SiC-SBD may be used. The number of semiconductor elements mounted may be one or more. The electrode portion on the surface of the semiconductor element 11 may be a Ni alloy (plating layer).

[0034] The laminated substrate 12 can be composed of an insulating substrate 122, a first conductive plate 121 formed on one of its main surfaces, and second conductive plates 123a, 123b formed on the other main surface. The insulating substrate 122 can be made of a material having excellent electrical insulation and thermal conductivity. Examples of the material for the insulating substrate 122 include Al2O3, AlN, and SiN. In particular, for high-voltage applications, a material having both electrical insulation and thermal conductivity is preferable, and AlN and SiN can be used, but are not limited to these. The first conductive plate 121 and the second conductive plates 123a, 123b can be made of metal materials such as Cu and Al that are easy to process. The conductive plates may be Cu or Al that have been treated with Ni plating or the like for the purpose of rust prevention. Methods for disposing the conductive plates 121, 123a, and 123b on the insulating substrate 122 include a direct copper bonding method and an active metal brazing method. In the illustrated embodiment, two second conductive plates 123a, 123b are discontinuously provided on an insulating substrate 122, with one second conductive plate 123a functioning as an electrode to be joined to the semiconductor element 11 and the other second conductive plate 123b functioning as an electrode to be connected to the lead frame 18.

[0035] The lead frame 18 is a conductive connection member that connects the semiconductor element 11 and the second conductive plate 123b and the like. The lead frame 18 is joined to the electrode (front surface electrode) of the semiconductor element 11 on the opposite side to the electrode (rear surface electrode) that contacts the laminated substrate 12, by a bonding layer 17 of a solder material or the like. The lead frame 18 is also joined to the wiring parts of the second conductive plate 123b and the like by a bonding layer 17 of a solder material or the like. The lead frame 18 may be a metal such as copper or an alloy containing copper. A Ni or Ni alloy layer, or a Cr or Cr alloy layer may be formed on the surface of the lead frame 18 by a plating method or the like. In this case, the film thickness of the Ni or Ni alloy layer, or the Cr or Cr alloy layer can be about 20 μm or less. The lead frame may be connected to an extraction terminal (not shown). These conductive connection members are used optionally, and may be wires such as aluminum.

[0036] The heat sink 13 is made of a metal such as copper or aluminum having excellent thermal conductivity. The heat sink 13 may be coated with Ni or a Ni alloy to prevent corrosion. The heat sink 13 may be a cooler having a function of water cooling or air cooling. There may also be a semiconductor device in which the case 16 is attached to the laminated substrate 12 and the heat sink 13 is not attached to the case 16.

[0037] The bonding layer 17 can be formed using lead-free solder. For example, Sn-Ag-Cu, Sn-Sb, Sn-Sb-Ag, Sn-Cu, Sn-Sb-Ag-Cu, Sn-Cu-Ni, Sn-Ag, etc. can be used, but are not limited to these. Alternatively, the bonding layer can be formed using a connecting material containing fine metal particles, such as a sintered body of nano-silver particles.

[0038] The case 16 may be made of a case material such as polyphenylene sulfide (PPS) or polybutylene terephthalate (PBT).

[0039] A primer layer may be provided on the surfaces of members such as the semiconductor element 11, the laminated substrate 12, and the aluminum wire 14 and lead frame 18, which are conductive connecting members, that come into contact with the sealing layer 20. The primer layer may be a layer of about 1 to 20 μm thick, composed of a thermoplastic resin containing polyamide, polyimide, and / or polyamideimide.

[0040] In FIG. 1, the sealing layer 20 is a resin cured product obtained by curing the resin composition according to the first embodiment. That is, the sealing layer 20 contacts the metal members including the conductive plates 121, 123a, 123b and the conductive connection member 18 and contains the resin composition according to the first embodiment (single layer structure). Note that even when a primer layer is provided on the surfaces of the conductive plates 121, 123a, 123b and the conductive connection member 18, the sealing layer 20 is defined as "contacting" the conductive plates 121, 123a, 123b and the conductive connection member 18 and containing the resin composition according to the first embodiment. In FIG. 1, the portion indicated by A is an example of an interface where the resin cured product obtained by curing the resin composition according to the first embodiment contacts the conductive plate 123a. Although not intending to be bound by theory, it is believed that at such an interface, hydroxyl groups generated by a crosslinking reaction between the epoxy group of the base material and the amino group of the curing agent form hydrogen bonds with hydroxyl groups present on the surface of the natural oxide film of copper or nickel constituting the conductive plate 123a. In addition, due to the structure of the curing agent, the plane formed by the six carbon atoms of the aromatic ring in the curing agent (the plane of the aromatic ring) is arranged approximately parallel to the interface and bonds to the substrate, which is thought to increase adhesion. First-principles calculations also revealed that stabilization occurs when the plane of the aromatic ring is parallel to the interface.

[0041] In another embodiment, although not shown, the sealing layer may be formed by laminating two or more layers of thermosetting resin compositions having different compositions. In this case, a sealing layer (first sealing layer) obtained by curing the semiconductor sealing resin composition according to the first embodiment is arranged in contact with the semiconductor element 11, the laminated substrate 12, and the conductive connecting member 18. If the thickness of the first sealing layer is at least 5 μm to 10 μm, the reliability of the semiconductor device can be improved as in the case of a single layer. Another sealing layer (second sealing layer) that does not contact the semiconductor element 11, the laminated substrate 12, and the conductive connecting member may be any thermosetting resin cured product obtained by curing a thermosetting resin composition that contains a thermosetting resin base material and an inorganic filler, and may optionally contain a curing agent, a curing accelerator, and an additive. In particular, the second sealing layer provided on the outer periphery of the semiconductor device is preferably a resin cured product using an acid anhydride such as phthalic anhydride that does not have an amine as a curing agent. This is because deterioration can be suppressed because there is no hydrogen nitride group that can react with moisture that enters from the outside.

[0042] Among the above-mentioned members constituting the semiconductor device of FIG. 1, the electrodes provided on the semiconductor element, the first conductive plate 121 and the second conductive plate 123a, b constituting the laminated substrate 12, conductive connection members such as the lead frame 18, the external terminal 15, and the heat sink 13 that may be optionally provided may be metal members that are insulated and sealed by contacting the resin composition according to the first embodiment. Conventionally, these metal members may be members that have been roughened for the purpose of improving adhesion with the resin, and there has been a concern that partial discharge may occur easily. In the semiconductor device according to the present invention, since the adhesion of the resin composition to the metal member is improved, it is not necessary to roughen the surface of the metal member. Therefore, in the semiconductor device according to this embodiment, a metal member having a flat surface with less concern of partial discharge may be used.

[0043] For the purpose of explaining the present invention, the semiconductor device according to the second embodiment has been described with reference to the cross-sectional structure of a specific module in FIG. 1, but the configurations of the laminated substrate, the semiconductor element, the conductive connection member, and the external terminal are not limited to those shown in the figure. For example, the conductive connection member is used optionally, and may be only one of a lead frame, a wire, and an implant pin, or may include two or more of these. For example, the semiconductor device may further include a printed circuit board connected to the front surface electrode of the semiconductor element by an implant pin, and the printed circuit board may be insulated and sealed. Alternatively, the semiconductor device may not include a case, and the sealing layer may be exposed on four side surfaces perpendicular to the main surface of the semiconductor element.

[0044] Next, the semiconductor device according to the second embodiment will be described from the viewpoint of a manufacturing method thereof. The manufacturing method of the semiconductor device includes the following steps. (1) A process for assembling a laminated substrate, a semiconductor element, and a conductive connecting member (2) A step of covering the laminated substrate, the semiconductor element, and the conductive connecting member with the resin composition according to the first embodiment.

[0045] (1) Placement and assembly process In the first step, the components constituting the semiconductor device are assembled. The heat sink 13, the laminated substrate 12, and the semiconductor element 11 are joined by a normal method, and then the case 16 is attached and fixed to the heat sink 13 using resin or the like. Thereafter, the lead frame 18 is joined, and wire bonding is performed using aluminum wires 14. Depending on the configuration of the semiconductor device, it is also possible to optionally join the implant pins and the printed circuit board. In addition, a step of forming a primer layer on the surfaces of the semiconductor element, the laminated substrate, and the conductive connecting member may also be performed.

[0046] (2) Sealing process In the second step, the assembled members are insulated and sealed with the resin composition according to the first embodiment according to a normal method to form the sealing layer 20. Specifically, the resin composition according to the first embodiment is injected into the case 16 and heat-cured. The heat-curing conditions include heating at 90 to 120°C for 1 to 2 hours to bring it into a semi-cured state, and heating at 175 to 185°C for 1 to 2 hours to fully cure it. However, the heat-curing conditions are not limited to specific temperature and time conditions, and there are cases where two-stage curing is not necessary. In addition, in an embodiment including two or more sealing layers composed of two or more resin compositions having different compositions, the multiple layers can be appropriately formed according to a normal method.

[0047] In the semiconductor device according to the present embodiment, the adhesion of the sealing layer to the metal member is improved, and the elastic modulus of the resin at the interface between the sealing layer and the metal member is reduced, resulting in a semiconductor device that is less susceptible to dielectric breakdown and has high reliability. EXAMPLES

[0048] The present invention will be described in more detail below with reference to examples of the present invention. However, the present invention is not limited to the scope of the following examples.

[0049] Resin compositions of Examples and Comparative Examples were prepared and their characteristics were evaluated. In addition, the power semiconductor module shown in FIG. 1 was manufactured using the resin compositions, and a reliability test was performed to evaluate the characteristics of the semiconductor device. The evaluation method will be described.

[0050] (1) Adhesion test The adhesion between the metal substrate made of nickel or copper with a natural oxide film formed on the surface, simulating a conductive plate or conductive connection member, and the resin composition of the examples or comparative examples was evaluated by a pudding cup-shear test. The resin composition of the examples or comparative examples was molded on the metal substrate so that the bottom diameter was 3.6 mm, the top diameter was 3.0 mm, and the height was 3.0 mm. Then, a thermal curing reaction was carried out at 100 to 180°C for 3 hours to obtain a test piece of the resin cured product molded on the substrate. The shear strength of the test piece was measured using a force gauge (load measuring device: Imada ZTA-1000N). The measurement conditions were as follows: the epoxy resin cured product was pressed parallel to the adhesive surface at a speed (strain rate) of 0.2 mm / s, and the strength at which the interface between the epoxy resin cured product and the metal substrate peeled off and broke was taken as the adhesion strength.

[0051] (2) Measurement of elastic modulus Two metal (Al) square bars (metal substrates) were prepared, each having a length of 50 mm and a square cross section with a side length of 3 mm. The resin composition of the example or comparative example was cured at 140°C for 20 hours to obtain a cured product. A resin sample having a thickness of 2 mm and a square cross section with a side length of 3 mm was cut out from this cured product. The cross sections of the two square bars were bonded together with the cut-out resin samples to obtain an evaluation sample. An elastic modulus measuring device (FG-1000 manufactured by Mori Engineering Co., Ltd.) was used to measure the elastic modulus. The measurement conditions were as follows: the square bar was vibrated at a sweep frequency of 100 Hz to 20 kHz to obtain the elastic modulus.

[0052] (3) Module reliability test The surfaces of the conductive plates (123a, 123b) and the conductive member 18 were made of Cu or Ni, and the components of the semiconductor device shown in FIG. 1 were assembled. Next, the resin composition of the example or comparative example was filled into the case and cured at a temperature of 150°C to 200°C for 2 hours to obtain a semiconductor device. The reliability of the semiconductor device was T j Power cycle resistance (T j The power cycle test was performed at 50 to 150°C (ΔT j= 100°C), with one cycle consisting of two seconds of power operation and eight seconds of rest, the number of cycles until the electrical characteristics reached abnormal values ​​was investigated. Specifically, power was applied from a state of 50°C to 150°C. A thermal resistance value that increased by 20% from the initial value was determined to be abnormal. The evaluation criteria were A for 80 kilocycles or more, B for 60 kilocycles or more but less than 80 kilocycles, C for 50 kilocycles or more but less than 60 kilocycles, and D for less than 50 kilocycles.

[0053] [Example 1] The resin composition and the semiconductor device were evaluated using the substrate (Cu or Ni metal substrate, etc.), epoxy resin base material, and curing agent shown in Table 1 below. The resin composition was prepared so that the inorganic filler was 70 mass% when the total mass of the base material, curing agent, and inorganic filler was 100%. The base material and the curing agent were mixed so that the volume ratio was 1:1. In all the examples and comparative examples, silica (SiO2) (manufactured by Nippon Electric Glass Co., Ltd.) with an average particle size of 10 μm was used as the inorganic filler. The resin composition was prepared by mixing the base material, the curing agent, and the inorganic filler. In the table, the substrate means the metal type in contact with the resin, and in Example 1, it was a natural oxide film of nickel. Bisphenol A type epoxy [80-05-7] is represented as Bis-A, diaminodiphenylmethane [101-77-9] is represented as DDM, and diaminodiphenylsulfone [80-8-0] is represented as DDS. In the following examples and comparative examples, the numbers in parentheses following the names of the epoxy resin base and curing agent represent CAS numbers. The oligomer type alicyclic epoxy EHPE-3150 and EPL GT401 were both manufactured by Daicel, and the alicyclic epoxy [3130-19-6] was manufactured by Sun Chemical Co., Ltd. The curing agents were all manufactured by Tokyo Chemical Industry Co., Ltd., and the bisphenol A type epoxy [80-05-7] was manufactured by Fujifilm Wako Pure Chemical Industries. The adhesion strength ratio and elastic modulus ratio were expressed as a ratio when the measured adhesion strength values ​​and measured elastic modulus values ​​of the samples of Comparative Examples 1-8 shown in Table 2 were set to 1.

[0054] The structures of the oligomeric alicyclic epoxies EHPE-3150 and EPLGT401 used are as follows: In the formula, l, m, n, and o each independently represent an integer of 1 to 30. [ka]

[0055] [Table 1]

[0056] [Comparative Example 1] The resin composition of the comparative example and the semiconductor device using the same were evaluated using the substrate, epoxy resin base, and curing agent shown in Table 2 below. The composition ratio and manufacturing method of each component of the resin composition were the same as in Example 1. In the table, diethylenetriamine [111-40-0] is represented as DETA, and m-phenylenediamine [108-45-2] is represented as MPDA. As for the curing agent, m-phenylenediamine [108-45-2] manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., phthalic anhydride [85-44-9] and diethylenetriamine [111-40-0] were used, both manufactured by Tokyo Chemical Industry Co., Ltd. The adhesion strength ratio and elastic modulus ratio were expressed as a ratio when the adhesion strength measurement value and elastic modulus measurement value of the sample of Comparative Example 1-8 shown in Table 2 were set to 1.

[0057] [Table 2]

[0058] From the results of Example 1 and Comparative Example 1, modules with high durability and high reliability ratings had an adhesion strength ratio of 1.4 or more and an elastic modulus ratio of 0.8 or less. In other words, it was confirmed that the use of a combination of a specific curing agent and an epoxy resin base improves the reliability of the module by about 10 to 60%.

[0059] The results of Example 1 and Comparative Example 1 are considered as follows, without being bound by theory. It was confirmed that the use of a diaminodiphenyl-based curing agent results in a lower modulus, higher adhesion, and higher module reliability, compared to acid anhydride-based curing agents, aliphatic amine-based curing agents, and amine-based curing agents having two amino groups on a single aromatic ring. The diaminodiphenyl-based curing agent has two aromatic rings via carbon or sulfur, and the degree of freedom to rotate between the aromatic rings is high, so it is presumed that the modulus of elasticity is reduced as a cured product (bulk). In particular, when the epoxy resin base agent is an alicyclic epoxy, when the terminal alicyclic epoxy group and the diaminodiphenyl-based curing agent crosslink, the six-membered ring of the base agent and the aromatic ring (phenyl group) of the curing agent are bonded via nitrogen, so that the degree of freedom to rotate between the six-membered ring and the aromatic ring around the reaction point is increased, and it is presumed that the modulus of elasticity is further reduced. On the other hand, the reason why the adhesion strength of the resin composition to the substrate metal is improved is presumably because the aromatic rings of the curing agent are oriented flatly relative to the substrate at the interfaces where the cured resin comes into contact with the conductive plates 123a, 123b and the conductive member 18, etc. The HOMO (Highest Occupied Molecular Orbital-LUMO (Lowest Unoccupied Molecular Orbital) of an aromatic ring extends perpendicularly to the plane of the six carbon atoms that make up the aromatic ring, and electrons are distributed perpendicular to this plane. Therefore, by orienting this plane flat against the substrate, it becomes easier to interact with the electrons on the substrate side, improving adhesion. Also, when the epoxy resin base is an alicyclic epoxy, when it is bonded with a curing agent, the six-membered ring of the alicyclic epoxy group and the aromatic ring of the curing agent come close to each other, and the planes of these six-membered rings or aromatic rings tend to be parallel to the bonded surface, improving adhesion. In addition, it is presumed that the resin contains a large amount of double-bonded oxygen (=O) in the base, which makes it easier to interact with hydroxyl groups adsorbed on the surface of the substrate metal, thereby improving adhesion.

[0060] The elastic modulus and adhesion are affected by the type of curing agent. It is unclear whether the elastic modulus or adhesion is the main factor in module reliability, but it is speculated that a slightly lower elastic modulus has the effect of stress relaxation. The reason why DDS has a higher elastic modulus and lower adhesion than DDM is that S has electron-attracting properties, and when crosslinked, electrons concentrate around S, creating a part that is close to crystal, and when it is slightly away from S, it creates a part with a low electron density and is amorphous, and it is speculated that this is repeated to create a polymer structure. It is speculated that this polymer structure has a slightly lower flexibility and a higher elastic modulus than DDM. It is speculated that the reason why resins containing alicyclic epoxy have a lower elastic modulus and higher adhesion than resins containing aliphatic epoxy is that the main agent, alicyclic epoxy, has a lower elastic modulus and higher flatness in structure than aliphatic epoxy. It is speculated that a crosslinked structure with high adhesion has a relatively flat structure of the polymer compound, and the number of contact points between the substrate and the polymer compound increases, so the adhesion strength increases. Conversely, it is speculated that a structure in which the flatness is lost will result in a decrease in adhesion strength.

[0061] [Example 2] The resin composition and the semiconductor device were evaluated using the substrate, epoxy resin base, and curing agent shown in Table 3 below. More specifically, the samples were prepared and measured in the same manner as in Example 1, except that the nickel on which a natural oxide film was formed in Example 1 was changed to copper on which a natural oxide film was formed. The abbreviations and manufacturer names of the reagents used are the same as in Example 1. The adhesion strength ratio and elastic modulus were expressed as a ratio when the measured adhesion strength value and measured elastic modulus value of the sample of Comparative Example 2-8 shown in Table 4 were set to 1.

[0062] [Table 3]

[0063] [Comparative Example 2] The resin composition and semiconductor device were evaluated using the substrate, epoxy resin base, and curing agent shown in Table 4 below. More specifically, samples were prepared and measured in the same manner as in Comparative Example 1, except that the nickel on which a natural oxide film was formed in Comparative Example 1 was changed to copper on which a natural oxide film was formed. The abbreviations and manufacturer names of the reagents used are the same as in Comparative Example 1. The adhesion strength ratio and elastic modulus were expressed as a ratio when the measured adhesion strength values ​​and measured elastic modulus values ​​of the samples of Comparative Examples 2-8 shown in Table 4 were taken as 1.

[0064] [Table 4]

[0065] [Example 3] The resin composition and the semiconductor device were evaluated in the same manner as in Example 1, except that two types of epoxy resin base materials were used in combination. The resin composition was prepared using base material 1, base material 2, and a curing agent shown in Table 5, and the inorganic filler was 70 mass% when the total mass of base material 1, base material 2, curing agent, and inorganic filler was 100%. Base material 1, base material 2, and curing agent were mixed in a volume ratio of 1:1:2. The adhesion strength ratio and elastic modulus ratio were expressed as a ratio when the adhesion strength measured value and elastic modulus measured value of the sample of Comparative Example 1-8 shown in the last row of Table 5 were set to 1. In the table, "-" means that the corresponding component is not included.

[0066] [Table 5]

[0067] [Example 4] The resin composition and the semiconductor device were evaluated in the same manner as in Example 3, except that the substrate was changed to a copper native oxide film. The resin composition used consisted of base material 1, base material 2, and a curing agent shown in Table 6. The adhesion strength ratio and elastic modulus ratio were expressed as a ratio when the measured adhesion strength value and measured elastic modulus value of the sample of Comparative Example 2-8 shown in the last row of Table 6 were set to 1. In the table, "-" means that the corresponding component was not included.

[0068] [Table 6]

[0069] [Example 5] The resin composition and the semiconductor device were evaluated in the same manner as in Example 4-1, except that the volume ratio of the main agent 1 (Bis-A) and the main agent 2 (oligomeric alicyclic epoxy EHPE-3150) was changed. In Table 7, the numerical values ​​in the items of Bis-A and oligomeric alicyclic epoxy EHPE-3150 are the volume ratios of each component to the total volume of these main agents and curing agent. The volume ratio of the curing agent was 50%, and the ratio of the total volume of the two main agents to the total volume was 50%. The adhesion strength ratio and the elastic modulus ratio were expressed as a ratio when the adhesion strength measurement value and the elastic modulus measurement value of the sample of Comparative Example 2-8 shown in the last row of Table 7 were set to 1.

[0070] [Table 7]

[0071] In particular, when the volume ratio of alicyclic epoxy to the total volume of aliphatic epoxy, alicyclic epoxy, and curing agent was 25% or more, and a curing agent having a diaminodiphenyl skeleton was used, it was confirmed that the adhesion was improved by 100% or more and the module reliability was improved by 60% or more compared to the case of phthalic anhydride (Comparative Example 2-1).

[0072] From the above results, it was confirmed that the use of the resin composition according to the present invention can realize high adhesion between the resin and metal and a low elastic modulus of the resin, thereby improving the reliability of the module. In particular, by using an alicyclic epoxy as the epoxy resin base, the adhesion can be increased by 1.5 times or more and the elastic modulus ratio can be increased to 0.7 or less compared to the resin composition according to the conventional technology, and a Pj power cycle resistance of 50 kilocycles or more, which is the reliability standard for semiconductor modules, can be achieved. [Explanation of symbols]

[0073] 11 semiconductor element, 12 laminated substrate, 121 first conductive plate, 122 insulating substrate 123a, 123b second conductive plate, 13 heat sink, 14 aluminum wire, 15 external terminal, 16 case, 17 bonding layer, 18 lead frame 20 Sealing layer

Claims

1. A resin composition for semiconductor encapsulation comprising one or more epoxy resin bases selected from alicyclic epoxies and aliphatic epoxies containing two or more aromatic rings, a curing agent having a diaminodiphenyl skeleton, and an inorganic filler.

2. 2. The semiconductor encapsulating resin composition according to claim 1, wherein the curing agent having a diaminodiphenyl skeleton is selected from the group consisting of 4,4'-diaminodiphenylmethane and 4,4'-diaminodiphenylsulfone.

3. 2. The semiconductor encapsulating resin composition according to claim 1, wherein the alicyclic epoxy is an alicyclic epoxy having two or more alicyclic epoxy groups in one molecule.

4. 2. The semiconductor encapsulating resin composition according to claim 1, wherein the epoxy resin base comprises an alicyclic epoxy and an aliphatic epoxy containing two or more aromatic rings.

5. 5. The semiconductor encapsulating resin composition according to claim 4, wherein the alicyclic epoxy is contained in an amount of 50% by volume or more based on the total volume of the epoxy resin base material.

6. A semiconductor element mounted on a laminated substrate including an insulating substrate and a conductive plate; A conductive connection member; a sealing layer that seals the semiconductor element and the conductive connection member; Equipped with A semiconductor device, comprising the semiconductor encapsulation resin composition according to claim 1 , wherein the encapsulation layer is in contact with the conductive plate and the conductive connecting member.

7. A semiconductor element mounted on a laminated substrate including an insulating substrate and a conductive plate; A conductive connection member; a sealing layer that seals the semiconductor element and the conductive connection member; A method for reducing an elastic modulus of the sealing layer at an interface between the conductive plate and the conductive connection member and improving adhesion of the sealing layer in a semiconductor device comprising the steps of: A method comprising the steps of placing the semiconductor encapsulation resin composition according to claim 1 in contact with the conductive plate and the conductive connecting member, and curing the composition.

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