Conductive adhesive film, method for joining dissimilar materials, semiconductor device structure, and dicing die-bonding film

Abstract

The present invention pertains to a conductive adhesive film (10) for joining a semiconductor device and a member, the conductive adhesive film (10) comprising: a stress relaxation layer (1) that is composed of a soft high-thermal-conductivity metal having a Young's modulus of 110 GPa or less at 25°C, a thermal conductivity of 100 W / m•K or more at 25°C, and a volume resistivity of 100 μΩ•cm or less; a first adhesive layer (2) that is provided on the side of the stress relaxation layer (1) to which the semiconductor device is joined, the first adhesive layer containing copper (Cu), tin (Sn), a bismaleimide resin, and an organic phosphine and / or an organic sulfide; and a second adhesive layer (3) that is provided on the side opposite the side of the stress relaxation layer (1) to which the semiconductor device is joined, the second adhesive layer containing copper (Cu), tin (Sn), a bismaleimide resin, and an organic phosphine and / or an organic sulfide.

Description

Conductive adhesive film, method for joining different materials, semiconductor device structure, and dicing die bond film

[0001] The present invention relates to a conductive adhesive film for bonding a semiconductor device to a member such as a substrate or a lead frame, a method for bonding different materials using a conductive adhesive film, a semiconductor device structure having a conductive adhesive film, and a dicing die bond film having a conductive adhesive film.

[0002] In recent years, large-capacity power semiconductors, such as SiC, have been widely used for the purpose of reducing power consumption. Large-capacity power semiconductors, such as SiC, have a wider bandgap than conventional silicon, allowing them to operate at a wider temperature range and at higher current densities. This allows devices incorporating large-capacity power semiconductors, such as SiC, such as motor inverters, to achieve both high performance and compact size.

[0003] However, although the switching performance of the large-capacity power semiconductor itself is maintained even at high current densities and the resulting high operating temperatures (junction temperatures), when the large-capacity power semiconductor is repeatedly exposed to high operating temperatures, the surrounding mounting components, particularly the lead-free solder used in the die bond portion, are destroyed by thermal fatigue caused by repeated exposure to high and low temperature environments, resulting in the failure of the device in which the large-capacity power semiconductor is mounted.

[0004] Therefore, it has been proposed to use a silver-based sintered material as a die-bonding material for large-capacity power semiconductors. For example, a semiconductor device bonding member (Patent Document 1) has been proposed, which includes a thermal stress relaxation layer made of any of silver, copper, gold, and aluminum, a first silver brazing material layer containing silver and tin as its main components and provided on the side of the thermal stress relaxation layer where the semiconductor device is bonded, and a second silver brazing material layer containing silver and tin as its main components and provided on the side of the thermal stress relaxation layer where the substrate is bonded.

[0005] However, with the silver-based sintered materials disclosed in Patent Document 1 and the like, in order to obtain a bonding state that is reliable and has excellent thermal fatigue resistance and can withstand repeated use at high operating temperatures, sintering at extremely high pressures under high temperature conditions of 300°C or higher is required, and there are major problems in terms of practicality due to the high cost of silver and the difficulty of the sintering process.

[0006] Furthermore, in the adhesive layer made of a silver brazing material layer mainly composed of silver and tin as described in Patent Document 1, an oxide film is formed on the silver and tin, and when a power semiconductor is joined to a member such as a substrate or a lead frame by transient liquid phase sintering (TLPS), the oxide film has the problem of inhibiting the transient liquid phase sintering reaction. Therefore, it has been studied to prevent the formation of the oxide film by reducing the oxide film by adding an alcohol-based or acid-based flux (reducing agent) to the adhesive layer mainly composed of silver and tin.

[0007] However, when alcohol-based or acid-based fluxes reduce the oxide film, water molecules are generated, and these water molecules cause voids in the sintered adhesive layer. Therefore, when using alcohol-based or acid-based fluxes, it is necessary to apply pressure to the semiconductor device structure in which the high-capacity power semiconductor is mounted on a substrate or the like in order to eliminate the voids. However, there is a problem in that applying pressure to the semiconductor device structure can cause damage such as cracks in the high-capacity power semiconductor.

[0008] Japanese Patent Application Laid-Open No. 2022-50871

[0009] The present invention has been made in consideration of the above circumstances, and aims to provide a conductive adhesive film that has excellent thermal fatigue resistance, ease of sintering, and void prevention properties without using expensive precious metals, a method for joining dissimilar materials using the conductive adhesive film, a semiconductor device structure having the conductive adhesive film, and a dicing die bond film having the conductive adhesive film.

[0010] The gist of the configuration of the present invention is as follows: [1] A conductive adhesive film for bonding a semiconductor device to a member, comprising: a stress relaxation layer made of a soft, highly thermally conductive metal having a Young's modulus at 25°C of 110 GPa or less, a thermal conductivity at 25°C of 100 W / m·K or more, and a volume resistivity of 100 μΩ·cm or less; a first adhesive layer provided on the side of the stress relaxation layer to which a semiconductor device is bonded, the first adhesive layer containing copper (Cu), tin (Sn), a bismaleimide resin, and an organic phosphine represented by the following general formula (1) and / or an organic sulfide represented by the following general formula (2); and a second adhesive layer provided on the side of the stress relaxation layer opposite the side to which the semiconductor device is bonded, the second adhesive layer containing copper (Cu), tin (Sn), a bismaleimide resin, and an organic phosphine represented by the following general formula (1) and / or an organic sulfide represented by the following general formula (2). (Chemical Formula 1) R １ -P(R ２ )-R ３ -P(R ４ )-R ５ ...(1) (In general formula (1), R １ , R ２ , R ３ , R ４ , R ５ each independently represents an aromatic or aliphatic organic group containing carbon (C) and hydrogen (H), and is one of the following functional groups: does not contain in the structure.) (Chemical formula 3) R ６ -S-R ７ ...(2) (In general formula (2), R ６ , R ７ each independently represents an aromatic or aliphatic organic group containing carbon (C) and hydrogen (H), and is one of the following functional groups: in its structure.) [2] The conductive adhesive film according to [1], wherein the first adhesive layer and the second adhesive layer contain an alloy containing copper (Cu) and nickel (Ni) and / or an alloy containing tin (Sn) and nickel (Ni), and have at least one endothermic peak in a temperature range of 100°C to 250°C in differential scanning calorimetry, and do not have the endothermic peak after heating at 250°C for 5 minutes in a nitrogen atmosphere at normal pressure. [3] The conductive adhesive film according to [1] or [2], wherein the soft, highly thermally conductive metal contains at least one metal selected from the group consisting of aluminum (Al) with a purity of 99.99% by mass or more and zinc (Zn) with a purity of 99% by mass or more. [4] The conductive adhesive film according to [1] or [2], further comprising a first barrier layer between the stress relaxation layer and the first adhesive layer, the first barrier layer containing at least one metal component selected from the group consisting of molybdenum (Mo), chromium (Cr), titanium (Ti), nickel (Ni), tin (Sn), and copper (Cu), and a second barrier layer between the stress relaxation layer and the second adhesive layer, the second barrier layer containing at least one metal component selected from the group consisting of molybdenum (Mo), chromium (Cr), titanium (Ti), nickel (Ni), tin (Sn), and copper (Cu). [5] The conductive adhesive film according to [1] or [2], wherein the organic phosphine has a melting point of 60°C or higher. [6] The conductive adhesive film according to [1] or [2], wherein the organic phosphine has a xanthene skeleton. [7] The conductive adhesive film according to [1] or [2], wherein the organic sulfide has a melting point of 60°C or higher. [8] The conductive adhesive film according to [1] or [2], wherein the organic sulfide has an acrylic group and / or a methacrylic group and / or a vinyl ether group. [9] The conductive adhesive film according to [1] or [2], wherein the first adhesive layer and the second adhesive layer further contain a compound represented by the following general formula (3): (Chemical Formula 5) Ar １ -C(R ８ ) (R ９ )-C(R １０ ) (R １１ ) -Ar ２ ...(3) (In general formula (3), Ar １ , Ar ２are each independently an aromatic group, R ８ , R ９ , R １０ , R １１ each independently represents an aliphatic group.)

[10] A method for joining dissimilar materials, using the conductive adhesive film according to [1] or [2], by pressureless sintering at 275°C or less for less than 10 minutes under atmospheric pressure in a nitrogen atmosphere, to join dissimilar materials having different linear expansion coefficients.

[11] A semiconductor device structure in which the semiconductor device is joined to the first adhesive layer of the conductive adhesive film according to [1] or [2], and a substrate or lead frame is joined to the second adhesive layer of the conductive adhesive film according to [1] or [2], and the semiconductor device is mounted on the substrate or lead frame.

[12] A dicing die bond film in which a dicing tape is attached to the second adhesive layer side of the conductive adhesive film according to [1] or [2].

[0011] In the above aspect [1], the first adhesive layer is sintered by transient liquid phase sintering (TLPS) or the like, so that a semiconductor device such as a power semiconductor is bonded to the stress relief layer made of a soft, highly thermally conductive metal via the sintered first adhesive layer, and the second adhesive layer is sintered by transient liquid phase sintering (TLPS) or the like, so that a member such as a substrate or a lead frame is bonded to the stress relief layer made of a soft, highly thermally conductive metal via the sintered second adhesive layer.

[0012] According to an embodiment of the conductive adhesive film of the present invention, by providing a stress relaxation layer made of a soft, highly thermally conductive metal having a Young's modulus at 25°C of 110 GPa or less, a thermal conductivity at 25°C of 100 W / m K or more, and a volume resistivity of 100 μΩ cm or less, the film has excellent thermal conductivity and electrical conductivity. Furthermore, even if the thermal expansion coefficients of the semiconductor device and the member on which the semiconductor device are mounted are different, thermal fatigue and stress accumulation are suppressed, thereby preventing damage to the semiconductor device structure on which the semiconductor device is mounted. Furthermore, according to an embodiment of the conductive adhesive film of the present invention, by providing a first adhesive layer and a second adhesive layer containing copper (Cu), tin (Sn), a bismaleimide resin, and an organic phosphine represented by the above general formula (1) and / or an organic sulfide represented by the above general formula (2), a conductive adhesive film with excellent thermal fatigue resistance, ease of sintering, and void prevention can be obtained without using expensive precious metals.

[0013] In addition, according to an aspect of the conductive adhesive film of the present invention, the first adhesive layer and the second adhesive layer contain an alloy containing copper (Cu) and nickel (Ni) and / or an alloy containing tin (Sn) and nickel (Ni), and have at least one endothermic peak within a temperature range of 100°C to 250°C in differential scanning calorimetry, and do not have the endothermic peak after heating at 250°C for 5 minutes in a nitrogen atmosphere at atmospheric pressure.This means that the first adhesive layer and the second adhesive layer can be sintered at atmospheric pressure, at a low temperature, and in a short time, thereby reliably improving sintering ease.

[0014] Furthermore, according to an embodiment of the conductive adhesive film of the present invention, the soft, highly thermally conductive metal contains at least one metal selected from the group consisting of aluminum (Al) with a purity of 99.99% by mass or more and zinc (Zn) with a purity of 99% by mass or more, thereby making it possible to more reliably prevent damage to the semiconductor device structure on which the semiconductor device is mounted, even if the thermal expansion coefficients of the semiconductor device and the member on which the semiconductor device is mounted are different.

[0015] In addition, according to an aspect of the conductive adhesive film of the present invention, a first barrier layer containing at least one metal component selected from the group consisting of molybdenum (Mo), chromium (Cr), titanium (Ti), nickel (Ni), tin (Sn) and copper (Cu) is further provided between the stress relaxation layer and the first adhesive layer, and a second barrier layer containing at least one metal component selected from the group consisting of molybdenum (Mo), chromium (Cr), titanium (Ti), nickel (Ni), tin (Sn) and copper (Cu) is further provided between the stress relaxation layer and the second adhesive layer. This prevents the metal components of the stress relaxation layer from diffusing into the first adhesive layer and the second adhesive layer, thereby preventing the formation of an alloy phase containing copper and tin from being inhibited by the metal components of the stress relaxation layer, and further improving sintering ease.

[0016] In addition, according to an embodiment of the conductive adhesive film of the present invention, the first adhesive layer and the second adhesive layer further contain a compound represented by the general formula (3), which acts as a curing agent for the bismaleimide resin, thereby improving the heat resistance of the first adhesive layer and the second adhesive layer. Furthermore, the compound represented by the general formula (3) is a non-oxide compound and does not interfere with the reducing agent, the organic phosphine represented by the general formula (1) and / or the organic sulfide represented by the general formula (2), thereby preventing the loss of void prevention properties.

[0017] Fig. 1 is a cross-sectional view schematically illustrating an outline of a conductive adhesive film in one embodiment of the conductive adhesive film according to the present invention. Fig. 2 is a cross-sectional view schematically illustrating an outline of a conductive adhesive film in another embodiment of the conductive adhesive film according to the present invention. Fig. 3 is a cross-sectional view schematically illustrating an outline of a semiconductor device structure in one embodiment of the semiconductor device structure according to the present invention. Fig. 4 is a cross-sectional view schematically illustrating an outline of a dicing die bond film in one embodiment of the dicing die bond film according to the present invention.

[0018] Embodiments of the conductive adhesive film of the present invention, a method for joining dissimilar materials using a conductive adhesive film, a semiconductor device structure having a conductive adhesive film, and a dicing die bond film having a conductive adhesive film are described in detail below with reference to the drawings.

[0019] 1 , the conductive adhesive film 10 of the present invention is a conductive adhesive film for bonding a semiconductor device and a member, and comprises a predetermined stress relaxation layer 1, a predetermined first adhesive layer 2 provided on the side of the stress relaxation layer 1 to which the semiconductor device is bonded, and a predetermined second adhesive layer 3 provided on the side of the stress relaxation layer 1 opposite to the side to which the semiconductor device is bonded. The stress relaxation layer 1 has a first main surface and a second main surface opposite to the first main surface, and the first adhesive layer 2 is provided on the first main surface, which is the side to which the semiconductor device is bonded, and the second adhesive layer 3 is provided on the second main surface, which is the side to which a member is bonded.

[0020] The thickness of the entire conductive adhesive film of the present invention can be appropriately selected depending on the conditions of use of the conductive adhesive film, etc., but the lower limit is preferably 10 μm, more preferably 30 μm, and particularly preferably 50 μm from the viewpoint of further alleviating the thermal stress generated between the semiconductor device and the member on which the semiconductor device is mounted. On the other hand, the upper limit of the thickness of the entire conductive adhesive film is preferably 300 μm, more preferably 250 μm, and particularly preferably 200 μm from the viewpoint of preventing an increase in the thermal resistance of the conductive adhesive film and improving its heat dissipation characteristics.

[0021] (1) Stress Relief Layer The stress relief layer in the conductive adhesive film of the present invention is composed of a soft, highly thermally conductive metal having a Young's modulus at 25°C of 110 GPa or less, a thermal conductivity at 25°C of 100 W / m·K or more, and a volume resistivity of 100 μΩ·cm or less. The stress relief layer is a layer that relieves thermal stress that occurs between a semiconductor device and a member on which the semiconductor device is mounted. The conductive adhesive film of the present invention has a stress relief layer composed of the above-mentioned soft, highly thermally conductive metal, which provides excellent thermal conductivity and electrical conductivity. Furthermore, even if the thermal expansion coefficients of the semiconductor device and the member on which the semiconductor device are mounted are different, the conductive adhesive film can flexibly deform in response to thermal stress. This suppresses thermal fatigue and stress accumulation between the semiconductor device and the member on which the semiconductor device is mounted, thereby preventing damage to the semiconductor device structure on which the semiconductor device is mounted.

[0022] The soft, highly thermally conductive metal is not particularly limited as long as it is a metal member having the properties of a Young's modulus at 25°C of 110 GPa or less, a thermal conductivity at 25°C of 100 W / m·K or more, and a volume resistivity of 100 μΩ·cm or less. However, even if the thermal expansion coefficients of the semiconductor device and the member on which the semiconductor device is mounted are different, aluminum (Al) with a purity of 99.99% by mass or more and zinc (Zn) with a purity of 99% by mass or more are preferred, and aluminum (Al) with a purity of 99.99% by mass or more is particularly preferred, because this more reliably suppresses the accumulation of thermal fatigue and stress between the semiconductor device and the member on which the semiconductor device is mounted, thereby more reliably preventing damage to the semiconductor device structure on which the semiconductor device is mounted.

[0023] The stress relaxation layer may be composed of a single layer of the soft, highly thermally conductive metal, or may be composed of multiple layers of the soft, highly thermally conductive metal. When the stress relaxation layer is composed of multiple layers of the soft, highly thermally conductive metal, it may be composed of only a layer of aluminum (Al) with a purity of 99.99% by mass or more, or only a layer of zinc (Zn) with a purity of 99% by mass or more, or may be composed of a layer of aluminum (Al) with a purity of 99.99% by mass or more and a layer of zinc (Zn) with a purity of 99% by mass or more.

[0024] As a physical property of the soft highly thermally conductive metal, the Young's modulus at 25° C. is preferably 100 GPa or less, and more preferably 80 GPa or less. On the other hand, the lower limit of the Young's modulus at 25° C. is not particularly limited, but is preferably 17 GPa or more from the viewpoint of imparting a certain level of strength to the stress relaxation layer.

[0025] The thermal conductivity of the soft, highly thermally conductive metal at 25° C. is preferably 150 W / m·K or more, and more preferably 200 W / m·K or more.

[0026] The volume resistivity of the soft, highly thermally conductive metal is preferably 40 μΩ·cm or less, and more preferably 10 μΩ·cm or less.

[0027] The thickness of the stress relaxation layer can be appropriately selected depending on the conditions of use of the conductive adhesive film of the present invention, and the lower limit is preferably 5 μm, more preferably 20 μm, and particularly preferably 40 μm, from the viewpoint of further relaxing the thermal stress occurring between the semiconductor device and the member on which the semiconductor device is mounted. On the other hand, the upper limit of the thickness of the stress relaxation layer is preferably 250 μm, more preferably 200 μm, and particularly preferably 150 μm, from the viewpoint of preventing an increase in the thermal resistance of the conductive adhesive film and improving the heat dissipation characteristics.

[0028] (2) First Adhesive Layer The first adhesive layer is provided on the side of the stress relaxation layer to which the semiconductor device is bonded, and contains copper (Cu), tin (Sn), a bismaleimide resin, and an organic phosphine represented by the following general formula (1) and / or an organic sulfide represented by the following general formula (2): (Chemical Formula 6) R １ -P(R ２ )-R ３ -P(R ４ )-R ５ ...(1) (In general formula (1), R １ , R ２ , R ３ , R ４ , R ５ each independently represents an aromatic or aliphatic organic group containing carbon (C) and hydrogen (H), and is one of the following functional groups: does not contain in the structure.) (Chemical formula 8) R ６ -S-R ７ ...(2) (In general formula (2), R ６ , R ７ each independently represents an aromatic or aliphatic organic group containing carbon (C) and hydrogen (H), and is one of the following functional groups: does not contain in the structure.)

[0029] By heat treating the conductive adhesive film of the present invention, the copper (Cu) and tin (Sn) components in the first adhesive layer are sintered by a transient liquid phase sintering (TLPS) reaction or the like, and in the sintered state (sintered state), an alloy phase containing copper (Cu) and tin (Sn) is formed, resulting in an increase in the melting point. Furthermore, a semiconductor device is bonded to the first adhesive layer in a state where the melting point of the first adhesive layer has been increased. Therefore, even when the operating temperature of a semiconductor device such as a power semiconductor is high, the bonding reliability between the first adhesive layer and the semiconductor device is excellent.

[0030] The first adhesive layer contains at least copper (Cu) and tin (Sn) as metal components, but does not contain precious metal components such as silver, etc. Therefore, the first adhesive layer does not contain expensive precious metals.

[0031] In the conductive adhesive film of the present invention, the organic phosphine represented by the following general formula (1) and the organic sulfide represented by the following general formula (2) function as a reducing agent. １ -P(R ２ )-R ３ -P(R ４ )-R ５ ...(1) (In general formula (1), R １ , R ２ , R ３ , R ４ , R ５ each independently represents an aromatic or aliphatic organic group containing carbon (C) and hydrogen (H), and is one of the following functional groups: does not contain in the structure.) (Chemical formula 12) R ６ -S-R ７ ...(2) (In general formula (2), R ６ , R ７each independently represents an aromatic or aliphatic organic group containing carbon (C) and hydrogen (H), and is one of the following functional groups: does not contain in the structure.)

[0032] If an oxide film is formed on the copper and tin metal components of the first adhesive layer, when the power semiconductor is bonded to a component such as a substrate or lead frame by sintering such as transient liquid phase sintering (TLPS), the oxide film inhibits the sintering reaction such as transient liquid phase sintering, i.e., inhibits the formation of an alloy phase containing copper and tin. However, the organic phosphine represented by general formula (1) and the organic sulfide represented by general formula (2) reduce the oxide film, thereby preventing the formation of an oxide film on the copper and tin. Therefore, even when copper and tin are used, which are metal components that are more easily oxidized than noble metals, the formation of an oxide film on the copper and tin can be prevented, and the sintering reaction such as transient liquid phase sintering is promoted, facilitating sintering and promoting the formation of an alloy phase containing copper and tin.

[0033] Neither the organic phosphine represented by general formula (1) nor the organic sulfide represented by general formula (2) contains the following functional group in its chemical structure: Therefore, when the organic phosphine represented by general formula (1) reduces the oxide film and chemically changes to an organic phosphine oxide, and when the organic sulfide represented by general formula (2) reduces the oxide film and chemically changes to an organic sulfoxide, no water molecules are generated as a by-product.

[0034] When the organic phosphine represented by general formula (1) chemically changes to organic phosphine oxide and the organic sulfide represented by general formula (2) chemically changes to organic sulfoxide, no water molecules are generated as by-products, preventing the generation of voids in the first adhesive layer in a sintered state. That is, the organic phosphine represented by general formula (1) and the organic sulfide represented by general formula (2) have excellent void prevention properties. From the above, when the first adhesive layer contains the organic phosphine represented by general formula (1) and / or the organic sulfide represented by general formula (2), it is not necessary to subject the semiconductor device structure in which the power semiconductor is mounted on a substrate or the like to pressure treatment to eliminate voids, and therefore damage such as cracking can be prevented from occurring in the power semiconductor.

[0035] In the conductive adhesive film of the present invention, the reducing agent may be either an organic phosphine represented by general formula (1) or an organic sulfide represented by general formula (2), or both an organic phosphine represented by general formula (1) and an organic sulfide represented by general formula (2) may be used in combination.

[0036] The melting point of the organic phosphine represented by general formula (1) is not particularly limited, but from the viewpoint of storage stability, it is preferable that the organic phosphine maintains a fine crystalline state before being introduced into the semiconductor device mounting process, thereby suppressing diffusion within the conductive adhesive film composition system and preventing the reaction from proceeding too quickly, and yet when it is introduced into the semiconductor device mounting process and heating is initiated, it is preferable that diffusion within the conductive adhesive film composition system quickly begins and the reaction can be initiated, from the viewpoint that it is preferable that it is 60°C or higher, and particularly preferable that it is 80°C or higher.

[0037] Specific examples of the organic phosphine represented by the general formula (1) include organic phosphines having a xanthene skeleton. １ , R ２ , R ４ , R ５ are each aromatic, and R ３ is an aromatic organic phosphine having a xanthene skeleton, and R １ , R ２ , R ４ , R ５ are each an optionally substituted phenyl group, R ３ In addition, the organic phosphine represented by the general formula (1) is particularly preferably an aromatic compound having a xanthene skeleton. １ , R ２ , R ４ , R ５ are each aromatic, and R ３ is preferably an organic phosphine in which R is aliphatic, １ , R ２ , R ４ , R ５ are each an optionally substituted phenyl group, R ３Aliphatic groups having 1 to 10 carbon atoms are particularly preferred.

[0038] The melting point of the organic sulfide represented by general formula (2) is not particularly limited, but from the viewpoint of storage stability, it is preferable that the organic sulfide maintains a fine crystalline state before being introduced into the semiconductor device mounting process, thereby suppressing diffusion within the conductive adhesive film composition system and preventing the reaction from proceeding too quickly, and yet when it is introduced into the semiconductor device mounting process and heating is initiated, it is preferable that diffusion within the conductive adhesive film composition system begins quickly and the reaction can begin, so that the melting point is preferably 60°C or higher, and particularly preferably 80°C or higher.

[0039] The organic sulfide represented by the general formula (2) is specifically, for example, an organic sulfide having an acrylic group and / or a methacrylic group and / or a vinyl ether group, i.e., R ６ , R ７ are preferably organic groups having an acrylic group and / or a methacrylic group and / or a vinyl ether group, and particularly preferably organic groups having an acrylic group and / or a methacrylic group. ６ , R ７ may each be an organic group having an aliphatic group such as an acrylic group and / or a methacrylic group and / or a vinyl ether group, and an aromatic group such as a phenyl group.

[0040] In the conductive adhesive film of the present invention, a bismaleimide resin is used as the thermosetting resin, which becomes a crosslinked polyimide having excellent heat resistance upon thermosetting because it can withstand the high operating temperatures of power semiconductors and has no protonic hydroxyl groups, thereby preventing the generation of outgassing. Furthermore, since the bismaleimide resin has stress relaxation properties, the thermal fatigue resistance of the conductive adhesive film after sintering is improved.

[0041] The amounts of the metal component containing copper and tin, the reducing agent composed of an organic phosphine represented by general formula (1) and / or an organic sulfide represented by general formula (2), and the bismaleimide resin in the first adhesive layer are not particularly limited. The lower limit of the amount of the metal component containing copper and tin in 100% by mass of the first adhesive layer is preferably 60% by mass, more preferably 70% by mass, and particularly preferably 75% by mass, from the viewpoint of obtaining a sintered first adhesive layer and improving the bonding reliability of the semiconductor device. On the other hand, the upper limit of the amount of the metal component containing copper and tin in 100% by mass of the first adhesive layer is preferably 95% by mass, more preferably 90% by mass, and particularly preferably 85% by mass.

[0042] The lower limit of the amount of the reducing agent composed of an organic phosphine represented by general formula (1) and / or an organic sulfide represented by general formula (2) in 100% by mass of the first adhesive layer is preferably 0.1% by mass, more preferably 1.0% by mass, and particularly preferably 1.5% by mass, from the viewpoint of improving sintering ease and void prevention. On the other hand, the upper limit of the amount of the reducing agent composed of an organic phosphine represented by general formula (1) and / or an organic sulfide represented by general formula (2) in 100% by mass of the first adhesive layer is preferably 20% by mass, more preferably 10% by mass, and particularly preferably 5% by mass.

[0043] The lower limit of the amount of bismaleimide resin in 100% by mass of the first adhesive layer is preferably 5% by mass, more preferably 10% by mass, and particularly preferably 15% by mass, in order to further improve thermal fatigue resistance, while the upper limit of the amount of bismaleimide resin in 100% by mass of the first adhesive layer is preferably 40% by mass, more preferably 35% by mass, and particularly preferably 30% by mass.

[0044] From the above, the conductive adhesive film of the present invention has a first adhesive layer containing copper, tin, bismaleimide resin, and an organic phosphine represented by the above general formula (1) and / or an organic sulfide represented by the above general formula (2), so that a conductive adhesive film with excellent thermal fatigue resistance, ease of sintering, and void prevention properties can be obtained without using expensive precious metals.

[0045] In the conductive adhesive film of the present invention, the first adhesive layer may contain, as a metal component, nickel (Ni) in addition to copper and tin, as necessary. That is, the metal component may include an alloy containing copper (Cu) and nickel (Ni) and / or an alloy containing tin (Sn) and nickel (Ni). Nickel promotes the formation of an alloy phase (intermetallic compound) containing copper and tin during sintering, thereby shortening the sintering reaction time.

[0046] Furthermore, when the first adhesive layer contains nickel (Ni), in differential scanning calorimetry (DSC) analysis, it is preferable that the first adhesive layer has at least one endothermic peak within a temperature range of 100°C to 250°C in the state before sintering (unsintered state), and that after heating at 250°C for 5 minutes in a nitrogen atmosphere at normal pressure, i.e., in the state after sintering (sintered state), it does not have the endothermic peak and the endothermic peak disappears.

[0047] In the unsintered state, at least one endothermic peak observed within the above temperature range indicates the melting point of at least one metal element constituting the metal component containing copper, tin, and nickel. In other words, when the unsintered first adhesive layer is heated (sintered) within the above temperature range, a specific metal component melts, spreading across the adherend (power semiconductor) surface, which is advantageous for mounting the power semiconductor at low temperatures. On the other hand, in the sintered state, no endothermic peak is observed within the above temperature range, which means that the melting point of the metal component containing copper, tin, and nickel does not exist within the above temperature range. In other words, once melted, the metal forms an alloy phase (intermetallic compound) containing copper and tin with a high melting point after sintering due to a diffusion reaction between the metals, resulting in excellent heat resistance.

[0048] The endothermic peak disappears after heating at 250°C for 5 minutes in a nitrogen atmosphere at atmospheric pressure, and the first adhesive layer is sintered at atmospheric pressure, at a low temperature, and in a short time, thereby reliably improving the ease of sintering the first adhesive layer. Furthermore, the first adhesive layer can be sintered at a low temperature (for mounting the power semiconductor), and exhibits excellent heat resistance after sintering (for mounting the power semiconductor).

[0049] The amount of nickel in 100% by mass of the first adhesive layer is not particularly limited, but the lower limit is preferably 0.01% by mass, more preferably 0.02% by mass, and particularly preferably 0.05% by mass in order to further improve the sintering reactivity of copper and tin. On the other hand, the upper limit of the amount of nickel in 100% by mass of the first adhesive layer is preferably 20% by mass, more preferably 15% by mass, and particularly preferably 10% by mass.

[0050] In the conductive adhesive film of the present invention, the first adhesive layer may further contain a compound represented by the following general formula (3), if necessary: ​​Ar １ -C(R ８ ) (R ９ )-C(R １０ ) (R １１ ) -Ar ２ ...(3) (In general formula (3), Ar １ , Ar ２ are each independently an aromatic group, R ８ , R ９ , R １０ , R １１ each independently represents an aliphatic group.

[0051] The compound represented by the general formula (3) is a thermal radical initiator and acts as a curing agent for the bismaleimide resin, improving the heat resistance and thermal fatigue resistance of the first adhesive layer. Furthermore, the compound represented by the general formula (3) is a non-oxide compound and does not interfere with the reducing agent, the organic phosphine represented by the general formula (1) and / or the organic sulfide represented by the general formula (2), thereby preventing the void prevention properties of the first adhesive layer from being impaired.

[0052] In general formula (3), Ar １ , Ar ２ each represents a phenyl group which may have a substituent, R ８ , R ９ , R １０ , R １１ are each independently preferably an aliphatic group having 1 to 10 carbon atoms, and Ar １ , Ar ２ are phenyl groups, R ８ , R ９, R １０ , R １１ are each independently an aliphatic group having 1 to 5 carbon atoms.

[0053] The amount of the compound represented by general formula (3) in 100% by mass of the first adhesive layer is not particularly limited, but the lower limit is preferably 0.01% by mass, more preferably 0.05% by mass, and particularly preferably 0.1% by mass, from the viewpoint of further improving the heat resistance and thermal fatigue resistance of the first adhesive layer. On the other hand, the upper limit of the amount of the compound represented by general formula (3) in 100% by mass of the first adhesive layer is preferably 2% by mass, more preferably 1% by mass, and particularly preferably 0.5% by mass.

[0054] The thickness of the first adhesive layer can be appropriately selected depending on the conditions of use of the conductive adhesive film of the present invention, but the lower limit is preferably 1 μm, more preferably 4 μm, and particularly preferably 8 μm from the viewpoint of ensuring reliable bonding between the semiconductor device and the stress relaxation layer, while the upper limit of the thickness of the first adhesive layer is preferably 50 μm, more preferably 40 μm, and particularly preferably 30 μm from the viewpoint of preventing an increase in the thermal resistance of the conductive adhesive film and improving the heat dissipation characteristics.

[0055] (3) Second Adhesive Layer The second adhesive layer is provided on the side of the stress relaxation layer opposite to the side to which the semiconductor device is bonded. For example, the second adhesive layer is provided on the side of the stress relaxation layer to which a member such as a lead frame or a substrate is bonded.

[0056] The second adhesive layer has the same component composition as the first adhesive layer described above. That is, the second adhesive layer contains copper (Cu), tin (Sn), a bismaleimide resin, and an organic phosphine represented by the following general formula (1) and / or an organic sulfide represented by the following general formula (2): (Chemical Formula 16) R １ -P(R ２ )-R ３ -P(R ４ )-R ５ ...(1) (In general formula (1), R １ , R ２ , R ３ , R ４ , R ５each independently represents an aromatic or aliphatic organic group containing carbon (C) and hydrogen (H), and is one of the following functional groups: does not contain in the structure.) (Chemical formula 18) R ６ -S-R ７ ...(2) (In general formula (2), R ６ , R ７ each independently represents an aromatic or aliphatic organic group containing carbon (C) and hydrogen (H), and is one of the following functional groups: does not contain in the structure.)

[0057] The second adhesive layer, like the first adhesive layer, may further contain nickel (Ni) as a metal component in addition to copper and tin, if necessary. Also, like the first adhesive layer, the second adhesive layer may further contain a compound represented by the following general formula (3): (Chemical Formula 20) Ar １ -C(R ８ ) (R ９ )-C(R １０ ) (R １１ ) -Ar ２ ...(3) (In general formula (3), Ar １ , Ar ２ are each independently an aromatic group, R ８ , R ９ , R １０ , R １１ each independently represents an aliphatic group.

[0058] The second adhesive layer has the same component composition as the first adhesive layer described above, so detailed explanations of each component and their effects will be omitted.

[0059] The thickness of the second adhesive layer can be appropriately selected depending on the conditions of use of the conductive adhesive film of the present invention, but the lower limit is preferably 1 μm, more preferably 4 μm, and particularly preferably 8 μm, from the viewpoint of ensuring reliable bonding between the stress relaxation layer and a member such as a lead frame or a substrate, while the upper limit of the thickness of the first adhesive layer is preferably 50 μm, more preferably 40 μm, and particularly preferably 30 μm, from the viewpoint of preventing an increase in the thermal resistance of the conductive adhesive film and improving the heat dissipation characteristics.

[0060] (4) First Barrier Layer As shown in FIG. 2, in the conductive adhesive film 10 of the present invention, if necessary, a first barrier layer 4 containing at least one metal component selected from the group consisting of molybdenum (Mo), chromium (Cr), titanium (Ti), nickel (Ni), tin (Sn) and copper (Cu) may further be provided between the stress relief layer 1 and the first adhesive layer 2.

[0061] By further providing a first barrier layer 4 between the stress relaxation layer 1 and the first adhesive layer 2, the metal components of the stress relaxation layer 1 can be prevented from diffusing into the first adhesive layer 2, thereby preventing the formation of an alloy phase containing copper and tin in the first adhesive layer 2 from being inhibited by the metal components of the stress relaxation layer 1, further improving the sinterability of the first adhesive layer 2.

[0062] (5) Second Barrier Layer As shown in FIG. 2, in the conductive adhesive film 10 of the present invention, if necessary, a second barrier layer 5 containing at least one metal component selected from the group consisting of molybdenum (Mo), chromium (Cr), titanium (Ti), nickel (Ni), tin (Sn) and copper (Cu) may be further provided between the stress relief layer 1 and the second adhesive layer 3.

[0063] By further providing a second barrier layer 5 between the stress relaxation layer 1 and the second adhesive layer 3, the metal components of the stress relaxation layer 1 can be prevented from diffusing into the second adhesive layer 3, thereby preventing the formation of an alloy phase containing copper and tin in the second adhesive layer 3 from being inhibited by the metal components of the stress relaxation layer 1, further improving the sinterability of the second adhesive layer 3.

[0064] <Method of Manufacturing Conductive Adhesive Film> Next, an example of a method of manufacturing the conductive adhesive film of the present invention will be described. First, the components constituting the first adhesive layer and the second adhesive layer are dissolved in an organic solvent such as toluene to prepare a conductive composition constituting the first adhesive layer and the second adhesive layer. Then, the prepared conductive composition is applied to both sides of a film-like soft, highly thermally conductive metal constituting the stress relaxation layer to a desired thickness. The application method is not particularly limited, and examples include known application methods such as a comma coater, screen printing, a bar coater, an applicator, a blade coater, a knife coater, a roll coater, and a gravure coater. After application of the conductive composition, a drying treatment is performed at 100°C to 150°C for 1 minute to 30 minutes, thereby forming a first adhesive layer on the first main surface of the stress relaxation layer, which is the side to which the semiconductor device is bonded, and a second adhesive layer on the second main surface, which is the side to which a member is bonded.

[0065] When a first barrier layer and a second barrier layer are further provided, before applying the conductive composition to the soft high thermal conductivity metal, the first barrier layer and the second barrier layer are formed on both sides of the soft high thermal conductivity metal by sputtering or the like, and the conductive composition is then applied onto the formed first barrier layer and second barrier layer.

[0066] <Method for joining dissimilar materials using a conductive adhesive film> As described above, the conductive adhesive film of the present invention can join components with different thermal expansion coefficients while suppressing thermal fatigue and stress accumulation, so that dissimilar materials with different linear expansion coefficients can be joined using the conductive adhesive film. Furthermore, as described above, the conductive adhesive film of the present invention can join dissimilar materials under easy sintering conditions because the first adhesive layer and the second adhesive layer are sintered at normal pressure, at low temperature, and in a short time.

[0067] First, members with different thermal expansion coefficients, such as a SiC power semiconductor and a lead frame or substrate on which the SiC power semiconductor is mounted, are prepared. Next, a structure is formed in which the conductive adhesive film of the present invention is interposed between the SiC power semiconductor and the lead frame or substrate. Next, the formed structure is heat-treated at normal pressure in an inert gas (e.g., nitrogen gas) atmosphere at a temperature of 275°C or less for less than 10 minutes. By the above heat treatment (pressureless sintering), the first adhesive layer and the second adhesive layer are sintered, making it possible to bond different materials (SiC power semiconductor and lead frame or substrate) with different linear expansion coefficients.

[0068] The lower limit of the heating temperature in the heat treatment is, for example, 230° C., and preferably 250° C. The lower limit of the heating time in the heat treatment is, for example, 3 minutes, and preferably 5 minutes.

[0069] 3, the semiconductor device structure 100 of the present invention has a structure in which a semiconductor device 20 such as a power semiconductor is mounted on a member such as a substrate or lead frame 30. In such a structure, in the semiconductor device structure 100, the semiconductor device 20 is bonded to the first adhesive layer of the conductive adhesive film 10 of the present invention described above, and the substrate or lead frame 30 is bonded to the second adhesive layer of the conductive adhesive film 10 of the present invention described above.

[0070] From the above, the semiconductor device structure of the present invention has a structure in which a semiconductor device such as a power semiconductor is mounted on a member such as a substrate or a lead frame via the conductive adhesive film of the present invention. Also, in the semiconductor device structure of the present invention, the conductive adhesive film of the present invention has the function of bonding the semiconductor device such as a power semiconductor to a member such as a substrate or a lead frame.

[0071] The semiconductor device structure of the present invention can be produced, for example, by placing a semiconductor device such as a power semiconductor on the surface of a member such as a substrate or lead frame via the conductive adhesive film of the present invention, and then subjecting the device to a heat treatment (e.g., reflow treatment) at a temperature of 275°C or less for less than 10 minutes under normal pressure in an inert gas (e.g., nitrogen gas) atmosphere.

[0072] The lower limit of the heating temperature in the heat treatment is, for example, 230° C., and preferably 250° C. The lower limit of the heating time in the heat treatment is, for example, 3 minutes, and preferably 5 minutes.

[0073] 4, the dicing die bond film 200 of the present invention has a structure in which a dicing tape 40 is attached to the second adhesive layer side of the above-described conductive adhesive film 10 of the present invention. That is, the dicing die bond film 200 of the present invention has an embodiment in which the conductive adhesive film 10 of the present invention and the dicing tape 40 are integrated.

[0074] By attaching a semiconductor wafer to the first adhesive layer of the conductive adhesive film of the present invention, the semiconductor wafer can be attached to a dicing tape via the conductive adhesive film of the present invention. The dicing die bond film of the present invention allows the semiconductor wafer to be attached to the dicing tape via the conductive adhesive film of the present invention, so that the semiconductor chips can be prevented from flying off when the semiconductor wafer is diced to a predetermined size to produce semiconductor chips.

[0075] Next, examples of the present invention will be described, but the present invention is not limited to these examples as long as they do not deviate from the spirit of the present invention. Also, room temperature is assumed to be within the range of 25°C ± 5°C.

[0076]

[0049] The components shown in Tables 1 to 3 below were dissolved in 100 ml of toluene in the formulations shown in Tables 1 to 3 below to prepare conductive compositions constituting the first adhesive layer and the second adhesive layer used in Examples 1 to 12 and Comparative Examples 1 to 4. The prepared conductive compositions were then applied using a comma coater to both sides of the metal films constituting the stress relaxation layers shown in Tables 1 to 3 below, and dried at 130°C for 3 minutes to form a first adhesive layer on the first main surface of the stress relaxation layer and a second adhesive layer on the second main surface, thereby preparing the conductive adhesive films of Examples 1 to 12 and Comparative Examples 2 to 4. In Comparative Example 1, the first adhesive layer and the second adhesive layer were directly bonded together to prepare the conductive adhesive film.

[0077] For the first and second barrier layers in Examples 7 to 12, before applying the conductive composition to the metal film constituting the stress relaxation layer, the first and second barrier layers were formed on both sides of the metal film constituting the stress relaxation layer by sputtering, and the conductive composition was then applied onto the formed first and second barrier layers using a comma coater.

[0078] Dicing die bond films of Examples 1 to 12 and Comparative Examples 1 to 4 were obtained by attaching a dicing tape having an acrylic adhesive on a polyolefin substrate to the conductive adhesive film prepared as described above.

[0079] Details of each component in Tables 1 to 3 below are as follows: Nofumer BC (non-oxide): 2,3-dimethyl-2,3-diphenylbutane, a curing agent for bismaleimide resin, manufactured by NOF Corporation.

[0080] Mounting Process Using the dicing die bond film of Examples 1 to 12 and Comparative Examples 1 to 4, a 0.2 mm thick Ag metallized SiC chip was bonded at 70 °C, and then diced to a size of 5 mm x 5 mm to obtain a SiC chip with a conductive adhesive film. The obtained SiC chip with the conductive adhesive film was picked up with a pickup die bonder and die-attached to an active metal copper circuit board (AMC board) with a Cu outer surface at 90 °C for 2 seconds. The die-attached sample was then mounted using a reflow furnace in a nitrogen atmosphere at normal pressure at the sintering temperatures and times listed in Tables 1 to 3, to obtain mounted samples of Examples 1 to 12 and Comparative Examples 1 to 4.

[0081] The evaluation and measurement items are as follows:

[0082] (1) Thermal Fatigue Resistance 1 The mounted samples of Examples 1 to 12 and Comparative Examples 1 to 4 were subjected to a thermal shock test (TCT) in a temperature range of -45°C to 200°C for 500 cycles, and the mounted samples after the test were visually inspected for peeling of the SiC chip and evaluated according to the following criteria, with a rating of △ or better being considered a pass: ◯: No peeling △: Partial peeling ×: Peeling over the entire surface

[0083] (2) Thermal Fatigue Resistance 2 The mounted samples of Examples 1 to 12 and Comparative Examples 1 to 4 were subjected to a thermal shock test (TCT) in a temperature range of -45°C to 230°C for 1000 cycles, and the mounted samples after the test were visually inspected for peeling of the SiC chip and evaluated according to the following criteria, with a rating of △ or better being considered a pass: ◯: No peeling △: Partial peeling ×: Peeling over the entire surface

[0084] (3) Shortest sintering time A conductive adhesive film was collected from the mounting samples of Examples 1 to 12, weighed out to 10 mg, and sealed in a dedicated aluminum pan to prepare a measurement sample. Using a high-sensitivity differential scanning calorimeter (Hitachi High-Tech Science Corporation, DSC7000X), a DSC chart was obtained in a nitrogen atmosphere (nitrogen flow rate 20 mL / min) in the range of room temperature to 350°C at a temperature increase rate of 5°C / min. The obtained DSC chart gave the shortest sintering time at which the disappearance of the endothermic peak in the temperature range of 200 to 250°C was observed.

[0085] For the mounting samples of Comparative Examples 1 to 3, the sintering temperature in the mounting process was set to 350°C, and for the mounting sample of Comparative Example 4, the sintering temperature in the mounting process was set to 350°C, and pressure was applied with a 250 g tungsten weight. Except for this, the shortest sintering time at which disappearance of the endothermic peak was observed was obtained in the same manner as in Examples 1 to 12.

[0086] (4) Void occurrence rate in sintered state For the mounted samples of Examples 1 to 12 and the mounted samples of Comparative Examples 1 to 4, the void occurrence rate (%) in the first adhesive layer and the second adhesive layer in the sintered state was detected by non-destructive internal inspection using ultrasonic flaw detection (SAT). Note that only the mounted sample of Comparative Example 4 was pressed using a tungsten weight during the mounting process. The void occurrence rate in the sintered state was evaluated according to the following criteria: ◎: Less than 3% ◯: 3% to 5% ×: More than 5%

[0087] (5) Reflow Workability A product having atmospheric pressure and a shortest sintering time of 10 minutes or less, which after reflowing under said conditions had a void generation rate in the sintered state rated as "○" or better, and which was also rated as "△" or better in a thermal shock test (TCT) in which 500 cycles were performed in a temperature range of -45°C to 200°C, was evaluated as "Excellent ◎". A product having atmospheric pressure and a shortest sintering time of more than 10 minutes, which after reflowing under said conditions had a void generation rate in the sintered state rated as "○" or better, and which was also rated as "△" or better in a thermal shock test (TCT) in which 500 cycles were performed in a temperature range of -45°C to 200°C, was evaluated as "○ Good". A product that did not satisfy even one of the conditions of atmospheric pressure, a shortest sintering time of 30 minutes or less, a void generation rate in the sintered state rated as "○" or better, and which was also rated as "△" or better in a thermal shock test (TCT) in which 500 cycles were performed in a temperature range of -45°C to 200°C, was evaluated as "× Poor".

[0088] The configurations, components and evaluation results of the conductive adhesive films of Examples 1 to 12 are shown in Tables 1 and 2 below, and the configurations, components and evaluation results of the conductive adhesive films of Comparative Examples 1 to 4 are shown in Table 3 below.

[0089]

[0090]

[0091]

[0092] As shown in Tables 1 and 2, Examples 1 to 12, in which the first adhesive layer and the second adhesive layer contained an organic phosphine represented by general formula (1) or an organic sulfide represented by general formula (2), had excellent sintering ease with the shortest sintering time of 5 to 30 minutes at 270°C, normal pressure, and also had excellent void prevention properties, with a void generation rate of 5% or less in the sintered state. Furthermore, Examples 1 to 12, in which aluminum (Al) with a purity of 99.99% by mass or more or zinc (Zn) with a purity of 99% by mass or more was used as the stress relaxation layer, also had excellent thermal fatigue resistance 1 and thermal fatigue resistance 2.

[0093] On the other hand, among Comparative Examples 1 to 4 in which the first adhesive layer and the second adhesive layer did not contain either the organic phosphine represented by general formula (1) or the organic sulfide represented by general formula (2), void prevention properties were not obtained in the mounting process at normal pressure in Comparative Examples 1 to 3, and pressure treatment in the mounting process was required to obtain void prevention properties in Comparative Example 4. Furthermore, in Comparative Examples 1 to 4 in which aluminum (Al) with a purity of 99.99% by mass or more or zinc (Zn) with a purity of 99% by mass or more was not used as the stress relaxation layer, thermal fatigue resistance was not obtained in the mounting process at normal pressure.

[0094] REFERENCE SIGNS LIST 1 stress relaxation layer 2 first adhesive layer 3 second adhesive layer 4 first barrier layer 5 second barrier layer 10 conductive adhesive film 20 semiconductor device 30 substrate (lead frame) 40 dicing tape 100 semiconductor device structure 200 dicing die bond film

Claims

1. A conductive adhesive film for bonding a semiconductor device to a member, comprising: a stress relaxation layer made of a soft, highly thermally conductive metal having a Young's modulus at 25°C of 110 GPa or less, a thermal conductivity at 25°C of 100 W / m·K or more, and a volume resistivity of 100 μΩ·cm or less; a first adhesive layer provided on the side of the stress relaxation layer to which a semiconductor device is bonded, the first adhesive layer containing copper (Cu), tin (Sn), a bismaleimide resin, and an organic phosphine represented by the following general formula (1) and / or an organic sulfide represented by the following general formula (2); and a second adhesive layer provided on the side of the stress relaxation layer opposite the side to which the semiconductor device is bonded, the second adhesive layer containing copper (Cu), tin (Sn), a bismaleimide resin, and an organic phosphine represented by the following general formula (1) and / or an organic sulfide represented by the following general formula (2). (Chemical Formula 1) R １ -P(R ２ )-R ３ -P(R ４ )-R ５ ...(1) (In general formula (1), R １ , R ２ , R ３ , R ４ , R ５ each independently represents an aromatic or aliphatic organic group containing carbon (C) and hydrogen (H), and is one of the following functional groups: does not contain in the structure.) (Chemical formula 3) R ６ -S-R ７ ...(2) (In general formula (2), R ６ , R ７ each independently represents an aromatic or aliphatic organic group containing carbon (C) and hydrogen (H), and is one of the following functional groups: does not contain in the structure.) 2. The conductive adhesive film according to claim 1, wherein the first adhesive layer and the second adhesive layer comprise an alloy containing copper (Cu) and nickel (Ni) and / or an alloy containing tin (Sn) and nickel (Ni), and have at least one endothermic peak within a temperature range of 100°C to 250°C in differential scanning calorimetry, and do not have the endothermic peak after heating at 250°C for 5 minutes in a nitrogen atmosphere at normal pressure.

3. A conductive adhesive film as described in claim 1 or 2, wherein the soft, highly thermally conductive metal comprises at least one metal selected from the group consisting of aluminum (Al) with a purity of 99.99% by mass or more and zinc (Zn) with a purity of 99% by mass or more.

4. A conductive adhesive film as described in claim 1 or 2, wherein a first barrier layer containing at least one metal component selected from the group consisting of molybdenum (Mo), chromium (Cr), titanium (Ti), nickel (Ni), tin (Sn), and copper (Cu) is further provided between the stress relief layer and the first adhesive layer, and a second barrier layer containing at least one metal component selected from the group consisting of molybdenum (Mo), chromium (Cr), titanium (Ti), nickel (Ni), tin (Sn), and copper (Cu) is further provided between the stress relief layer and the second adhesive layer.

5. The conductive adhesive film according to claim 1 or 2, wherein the melting point of the organic phosphine is 60°C or higher.

6. A conductive adhesive film according to claim 1 or 2, wherein the organic phosphine has a xanthene skeleton.

7. The conductive adhesive film according to claim 1 or 2, wherein the melting point of the organic sulfide is 60°C or higher.

8. The conductive adhesive film according to claim 1 or 2, wherein the organic sulfide has an acrylic group and / or a methacrylic group and / or a vinyl ether group.

9. The conductive adhesive film according to claim 1 or 2, wherein the first adhesive layer and the second adhesive layer further contain a compound represented by the following general formula (3): (Chemical Formula 5) Ar １ -C(R ８ ) (R ９ )-C(R １０ ) (R １１ ) -Ar ２ ...(3) (In general formula (3), Ar １ , Ar ２ are each independently an aromatic group, R ８ , R ９ , R １０ , R １１ each independently represents an aliphatic group.

10. A method for joining dissimilar materials having different linear expansion coefficients, using the conductive adhesive film of claim 1 or 2, by pressureless sintering at 275°C or less for less than 10 minutes in a nitrogen atmosphere at normal pressure.

11. A semiconductor device structure in which the semiconductor device is bonded to the first adhesive layer of the conductive adhesive film described in claim 1 or 2, and a substrate or lead frame is bonded to the second adhesive layer of the conductive adhesive film described in claim 1 or 2, and the semiconductor device is mounted on the substrate or lead frame.

12. A dicing die bond film in which a dicing tape is attached to the second adhesive layer side of the conductive adhesive film according to claim 1 or 2.

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