Method for manufacturing semiconductor device

Abstract

To restrain deformation of a connection portion of a semiconductor chip or the like which is caused by connection while ensuring good electrical conductivity in a case where a semiconductor device is manufactured by a method including connecting the connection portion by metal bonding.SOLUTION: A method for manufacturing a semiconductor device includes forming a provisionally-crimped body by heating and pressurizing a laminate 100 having a first circuit member 1, a second circuit member 2, and a thermosetting adhesive layer 3 with pressing members 41, 42, and forming a connection body by heating the provisionally-crimped body under a pressurized atmosphere. The first circuit member 1 may be a semiconductor chip. The laminate 100 is pressurized by the pressing members 41, 42 at a predetermined pressure of 1.50 MPa or less. During a part or the whole of a period during which the laminate 100 is heated and pressurized by the pressing members 41, 42, at least one of the pressing members 41, 42 is heated to a provisionally-crimping temperature equal to or greater than an onset temperature of the thermosetting adhesive layer 3.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a method for manufacturing a semiconductor device. [Background technology]

[0002] In the manufacture of semiconductor devices, a flip-chip connection method is sometimes adopted in which conductive protrusions called bumps are provided as connection parts on a semiconductor chip or a wiring circuit board, and the semiconductor chip is connected to the wiring circuit board or another semiconductor chip via an adhesive by connecting the connection parts together. For example, Patent Document 1 discloses the manufacture of a semiconductor device by a flip-chip connection method including a process of obtaining a temporary compression bonded body in which semiconductor chips are temporarily compression bonded together, and a process of joining the connection parts together by heating the temporary compression bonded body while applying pressure. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 194156 Summary of the Invention [Problem to be solved by the invention]

[0004] When manufacturing a semiconductor device by a method including connecting a connection part of a semiconductor chip or a semiconductor wafer to a connection part of another semiconductor chip, etc. by metal bonding, a part of the connection part may be crushed and significantly deformed during the connection. Such a large deformation of the connection part may cause a decrease in connection reliability.

[0005] The present disclosure relates to suppressing deformation of a connection portion associated with connection while ensuring good electrical continuity when manufacturing a semiconductor device by a method that includes connecting a connection portion of a semiconductor chip or semiconductor wafer to a connection portion of another semiconductor chip or the like by metal bonding. [Means for solving the problem]

[0006] The present disclosure includes the following. [1] a laminate including a first circuit member having a first connection portion including a first metal material, a second circuit member having a second connection portion including a second metal material, and a thermosetting adhesive layer, the thermosetting adhesive layer being interposed between the first circuit member and the second circuit member, the laminate being heated and pressurized by a pair of opposing pressing members, thereby forming a temporary pressure-bonded body in which the first connection portion and the second connection portion are in contact with each other; heating the temporary pressure-bonded body to a predetermined full pressure-bonding temperature under a pressurized atmosphere, thereby forming a connection body in which the first connection portion and the second connection portion are electrically connected by metal bonding between the first metal material and the second metal material; A method for manufacturing a semiconductor device, comprising: The first circuit member is a semiconductor chip or a semiconductor wafer, and the second circuit member is a wiring circuit board, a semiconductor chip, or a semiconductor wafer; The laminate is pressed by the pair of pressing members at a predetermined pressure of 1.50 MPa or less, During a part or the whole of the time during which the laminate is heated and pressurized by the pair of pressing members, at least one of the pair of pressing members is heated to a predetermined temporary pressure-bonding temperature, and the temporary pressure-bonding temperature is a temperature that is equal to or higher than an onset temperature of the thermosetting adhesive layer and is lower than the main pressure-bonding temperature, the onset temperature is the onset temperature of an exothermic peak showing the largest amount of heat generation in a DSC curve obtained by differential scanning calorimetry under conditions in which a sample of the thermosetting adhesive layer is heated at a temperature increase rate of 10° C. / min; The main compression bonding temperature is a temperature equal to or higher than at least one of the melting point of the first metal material and the melting point of the second metal material under the pressurized atmosphere. method. [2] The method according to [1], wherein the predetermined pressure is 0.94 MPa or more and 1.50 MPa or less. [3] The method according to [1] or [2], wherein the pre-compression temperature is equal to or higher than the onset temperature and equal to or lower than 200° C. [4] The method according to any one of [1] to [3], wherein the laminate is heated and pressed by the pair of pressing members for 5 seconds or less. [5] The method according to any one of [1] to [4], wherein the thermosetting adhesive layer exhibits a shear viscosity of 10,000 Pa s or less at a temperature 20° C. lower than the onset temperature, and the shear viscosity is a value measured under conditions of a heating rate of 10° C. / min, a frequency of 10 Hz, and a strain of 1%. [6] The method according to any one of [1] to [5], wherein the time for which the pre-bonded body is heated under the pressurized atmosphere to a temperature equal to or higher than at least one of the melting point of the first metal material or the melting point of the second metal material is 60 seconds or less. [7] The method according to any one of [1] to [6], wherein the pressure of the pressurized atmosphere is higher than atmospheric pressure and is 0.90 MPa or less. [8] The thermosetting adhesive layer is a thermosetting resin having a molecular weight of less than 10,000; A curing agent for the thermosetting resin; A polymer component having a weight average molecular weight of 10,000 or more; The method according to any one of [1] to [7], [9] The method according to [8], wherein the polymer component has a glass transition temperature of 200°C or lower.

[10] The method according to any one of [1] to [9], wherein the thermosetting resin layer exhibits a shear viscosity of 10,000 Pa·s or more at 40° C. Effect of the Invention

[0007] In the case of manufacturing a semiconductor device by a method including connecting a connection part of a semiconductor chip to a connection part of another semiconductor chip or the like by metal bonding, it is possible to suppress deformation of the connection part due to the connection. Also, good electrical continuity between the connection parts can be easily ensured. [Brief description of the drawings]

[0008] [Figure 1] 1A to 1C are process diagrams showing an example of a method for manufacturing a semiconductor device. [Diagram 2] 1A to 1C are process diagrams showing an example of a method for manufacturing a semiconductor device. [Diagram 3] 1A to 1C are process diagrams showing an example of a method for manufacturing a semiconductor device. [Figure 4] FIG. 2 is a schematic diagram showing a method for determining an onset temperature from a DSC curve. [Diagram 5] 1 is a cross-sectional photograph of a connection portion of a connector. [Figure 6] 1 is a cross-sectional photograph of a connection portion of a connector. [Figure 7] 1 is a cross-sectional photograph of a connection portion of a connector. [Figure 8] 1 is a cross-sectional photograph of a connection portion of a connector. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The present invention is not limited to the following examples.

[0010] 1, 2 and 3 are process diagrams showing an example of a method for manufacturing a semiconductor device. The method shown in FIGS. 1 to 3 includes preparing a laminate 100 having a first circuit member 1 having a first connecting portion 15 containing a first metal material, a second circuit member 2 having a second connecting portion 25 containing a second metal material, and a thermosetting adhesive layer 3, heating and pressing the laminate 100 with a pair of opposing pressing members 41, 42, thereby forming a temporary pressure-bonded body 101 in which the first connecting portion 15 and the second connecting portion 25 are in contact with each other, and heating the temporary pressure-bonded body 101 to a full pressure-bonding temperature under a pressurized atmosphere, thereby forming a connecting body 102 (semiconductor device) in which the first connecting portion 15 and the second connecting portion 25 are electrically connected by metal bonding between the first metal material and the second metal material. The first circuit member 1 may be a semiconductor chip or a semiconductor wafer. The second circuit member 2 may be a wiring circuit board, a semiconductor chip, or a semiconductor wafer.

[0011] The laminate 100 is prepared, for example, as shown in FIG. 1 , by a method including: preparing a first circuit member 1 (e.g., a semiconductor chip) having a plate-shaped main body 10 and a plurality of first connection portions 15 arranged on the main surface of the main body 10; providing a thermosetting adhesive layer 3 on the surface of the first circuit member 1 facing the first connection portions 15; preparing a plate-shaped main body 20 and a second circuit member 2 having second connection portions 25 arranged on the main surface of the main body 20; and arranging the first circuit member 1 on the second circuit member 2 such that the thermosetting adhesive layer 3 is interposed between the first circuit member 1 and the second circuit member 2 and the first connection portions 15 and the second connection portions 25 are arranged opposite each other.

[0012] The main body 10 of the first circuit member 1 (semiconductor chip or semiconductor wafer) is not particularly limited and may have various semiconductor substrates and integrated circuits. The main body 10 may include, for example, an elemental semiconductor composed of the same type of elements such as silicon and germanium, or a compound semiconductor such as gallium arsenide and indium phosphide.

[0013] The first connection portion 15 of the first circuit member 1 has a metal pillar 11 and a bump 12 provided on the metal pillar 11. The first metal material is included in the bump 12, which is a portion joined to the second connection portion 25. The metal pillar 11 may be, for example, a copper pillar. The melting point of the first metal material included in the bump 12 may be 220°C or more and 330°C or less, or 140°C or more and 220°C or less. The bump 12 may be a solder bump containing a solder as the first metal material. The first metal material may be a solder containing a Sn-Ag alloy, a Sn-Pb alloy, a Sn-Bi alloy, a Sn-Cu alloy, or a Sn-Ag-Cu alloy.

[0014] The wired circuit board as the second circuit member 2 has, for example, an insulating substrate as the main body 20 and wiring including the second connection portion 25 provided on the insulating substrate. The insulating substrate may be, for example, a glass epoxy substrate, a polyimide resin substrate, a polyester resin substrate, or a ceramic substrate. The semiconductor chip as the second circuit member 2 may have a semiconductor substrate and an integrated circuit, similar to the first circuit member 1. The semiconductor wafer as the second circuit member 2 may include a plurality of portions corresponding to the semiconductor chips.

[0015] The second connection portion 25 of the second circuit member 2 can be, for example, a metal pad including a second metal material. The second metal material may be, for example, gold, silver, copper, solder, tin, nickel, or a combination thereof. The solder as the second metal material may include a Sn-Ag alloy, a Sn-Pb alloy, a Sn-Bi alloy, a Sn-Cu alloy, or a Sn-Ag-Cu alloy.

[0016] The thermosetting adhesive layer 3 is a layer formed by a thermosetting adhesive, and is provided on the first circuit member 1 by, for example, attaching a preformed film-like thermosetting adhesive to the first circuit member 1. The film-like thermosetting adhesive can be attached to the first circuit member 1 by, for example, heat pressing, roll lamination, or vacuum lamination. The area and thickness of the film-like thermosetting adhesive are appropriately set according to the size of the first circuit member 1, the height of the first connection portion 15, and the like. The thickness of the film-like thermosetting adhesive and the thermosetting adhesive layer 3 may be, for example, 1 μm or more and 60 μm or less. The semiconductor wafer to which the film-like thermosetting adhesive is attached may be divided by dicing to prepare a semiconductor chip to which the thermosetting adhesive layer 3 is attached as the first circuit member 1. The thermosetting adhesive layer 3 and the thermosetting adhesive forming it will be described in detail later.

[0017] 2, a pair of pressing members 41, 42 are arranged opposite to each other, and the laminate 100 is heated and pressed by being sandwiched between the pressing member 41 arranged on the second circuit member 2 side and the pressing member 42 arranged on the first circuit member 1 side. A temporary pressure-bonding step including this heating and pressing forms a temporary pressure-bonded body 101. During part or all of the time during which the laminate 100 is heated and pressed by the pressing members 41, 42, the pressing member 41, the pressing member 42, or both of them are heated to a predetermined temporary pressure-bonding temperature.

[0018] The laminate 100 is heated by heat transfer from the pressing member in contact with the laminate 100. For example, the pressing member 41 arranged on the second circuit member 2 side may be a stage, and the pressing member 42 on the first circuit member 1 side may be a pressure bonding head. The first circuit member 1 may be adsorbed to the pressing member 42, which is a pressure bonding head, and the connection parts may be aligned by moving the pressure bonding head. For this purpose, a pressure bonding machine such as a flip chip bonder having a pressure bonding head may be used. The first circuit member 1 and the thermosetting adhesive layer 3 adsorbed to the pressing member 42, which is a pressure bonding head, may be arranged on the second circuit member 2 to form the laminate 100, and the laminate 100 may be pressed by the pressure bonding head (pressing member 42) as it is.

[0019] The temporary pressure bonding temperature is a constant temperature set in a range equal to or higher than the onset temperature of the thermosetting adhesive layer 3. The onset temperature here is the onset temperature of the exothermic peak showing the largest amount of heat in a DSC curve obtained by differential scanning calorimetry under the condition that a sample that is a part of the thermosetting adhesive layer 3 is heated at a temperature increase rate of 10 ° C. / min. FIG. 4 is a schematic diagram showing a method for determining the onset temperature from a DSC curve. The DSC curve shown in FIG. 4 includes a baseline L0 and an exothermic peak P due to the curing reaction of the thermosetting adhesive layer 3 observed in the middle of the baseline L0 in the temperature range of 60 to 280 ° C. The onset temperature is the temperature T at the intersection between the extension line L1 of the baseline L0 at the bottom of the exothermic peak P and the tangent line L2 of the DSC curve at the point where the DSC curve shows the maximum gradient on the low temperature side of the temperature at which the exothermic peak P shows the maximum maximum value. The exothermic peak may include one or more shoulder peaks in addition to the maximum peak showing the maximum maximum value. When the exothermic peak includes one or more shoulder peaks located on the lower side than the temperature at which the maximum maximum value is shown, the onset temperature is the temperature at the intersection of the tangent to the DSC curve at the point where the DSC curve on the lower side of the lowest shoulder peak shows the maximum gradient and an extension of the baseline of the DSC curve.

[0020] If the temporary pressure-bonding temperature is equal to or higher than the onset temperature, the viscosity of the thermosetting adhesive layer 3 is significantly reduced during the heating and pressurizing for forming the temporary pressure-bonded body, and therefore the thermosetting adhesive layer 3 is likely to be sufficiently removed from between the first connecting portion 15 and the second connecting portion 25. Therefore, even if the heating and pressurizing conditions in the main pressure-bonding process for forming the connecting body 102 from the temporary pressure-bonded body 101 are relatively mild, good electrical continuity is likely to be ensured. As a result, deformation of the connecting portion (e.g., bump 12) in the connecting body 102 can be suppressed.

[0021] From the above viewpoint, the temporary compression bonding temperature may be a temperature higher than the onset temperature by 1° C., 2° C., 3° ​​C., 4° C., or 5° C. or more. The temporary compression bonding temperature may be 200° C. or lower, 195° C. or lower, 190° C. or lower, or 185° C. or lower. The temporary compression bonding temperature is usually a temperature lower than the melting point of the first metal material and the melting point of the second metal material.

[0022] The onset temperature of the thermosetting adhesive layer 3 may be, for example, 140° C. or more and 190° C. or less. The onset temperature of the thermosetting adhesive layer 3 may be 145° C. or more, 150° C. or more, or 155° C. or more, and may be 185° C. or less, 180° C. or less, 175° C. or less, 170° C. or less, or 165° C. or less.

[0023] While the laminate 100 is heated and pressed by the pressing members 41 and 42, the temperature (heating temperature) of the pressing members 41 and 42, or both of them, may be substantially maintained at a constant pre-compression temperature equal to or higher than the onset temperature, or may fluctuate. However, even if the heating temperature is substantially maintained at a constant pre-compression temperature, the actual heating temperature may fluctuate to a certain extent (for example, within a range of the pre-compression temperature ±1°C). When the heating temperature fluctuates, it is set so that the maximum temperature becomes the predetermined pre-compression temperature.

[0024] If the time (pre-pressure bonding time) during which the laminate 100 is heated and pressed by the pressing members 41 and 42 is appropriately short, the curing reaction of the thermosetting adhesive layer 3 tends not to proceed excessively at the stage before heating at the main pressure bonding temperature. Therefore, the pre-pressure bonding time may be 5 seconds or less, 4 seconds or less, 3 seconds or less, or 2 seconds or less, or may be 0.5 seconds or more, or 1 second or more.

[0025] In order to form the temporary pressure-bonded body 101, a predetermined pressure is applied to the laminate 100 by the pressing members 41 and 42. If this pressure is appropriately small, deformation of the connection portion is easily suppressed while voids and the thermosetting adhesive layer 3 are sufficiently removed from between the connection portions. From this viewpoint, the predetermined pressure for forming the temporary pressure-bonded body 101 may be 1.50 MPa or less, or may be 0.94 MPa or more and 1.50 MPa or less. Pressurization at a pressure within this range may be advantageous in terms of avoiding a decrease in connection reliability due to damage to the connection portion. From the same viewpoint, the predetermined pressure for forming the temporary pressure-bonded body 101 may be 1.45 MPa or less, 1.40 MPa or less, or 1.35 MPa or less, or may be 1.0 MPa or more, 1.05 MPa or more, or 1.1 Ma or more. In order to form the temporary pressure-bonded body 101, the load applied to the entire laminate 100 by the pressing members 41 and 42 may be 50 N or more and 80 N or less.

[0026] An additional thermosetting adhesive layer and an additional circuit member (e.g., a semiconductor chip) may be further provided on the side of the first circuit member 1 opposite to the second circuit member 2. In this case, each circuit member may be laminated in sequence by a temporary pressure bonding process, or a temporary pressure bonded body may be formed by a temporary pressure bonding process in which a laminate having three or more circuit members is heated and pressed collectively. When three or more circuit members are laminated, a semiconductor chip having a TSV structure may be used as the circuit member.

[0027] 3(a), the temporary pressure-bonded body 101 is heated to a predetermined permanent pressure-bonding temperature in a pressurized atmosphere in a heating furnace 50 to form a connection body 102. The permanent pressure-bonding temperature for forming the connection body 102 is set to a range equal to or higher than at least one of the melting point of the first metal material or the melting point of the second metal material. The temporary pressure-bonded body 101 is heated at a heating temperature that reaches a permanent pressure-bonding temperature equal to or higher than at least one of the melting point of the first metal material or the melting point of the second metal material, thereby forming a metal bond between the first metal material and the second metal material. For example, in the permanent pressure-bonding process, the bump 12 of the first connection portion 15 melts, and the deformed bump 12 is interposed between the metal pillar 11 and the second connection portion 25, thereby electrically connecting the first connection portion 15 and the second connection portion 25.

[0028] The heating in the main pressure bonding step also advances the curing reaction of the thermosetting adhesive layer 3, and an adhesive layer 3A is formed as a cured thermosetting adhesive. For example, the connecting body 102 can be a semiconductor device including a semiconductor chip as the first circuit member 1, a second circuit member 2, and an adhesive layer 3A. After the main pressure bonding step, the connecting body 102 may be further heated to further advance the curing reaction of the thermosetting adhesive.

[0029] The furnace 50 may be, for example, a pressurized reflow furnace or a pressurized oven. The gas forming the pressurized atmosphere within the furnace 50 may include air, nitrogen, or formic acid.

[0030] The heating temperature of the temporarily-bonded body 101 in the permanent bonding step may be constant or may vary, but the temporarily-bonded body 101 is heated so that the maximum temperature becomes the permanent bonding temperature. The heating temperature here may be the temperature of the pressurized atmosphere.

[0031] The temperature for the main bonding may be, for example, 220° C. or higher and 330° C. or lower. When the temperature for the main bonding is within this range, the metal bond is easily formed well while preventing scattering of the connection and formation of voids in the connection due to excessive alloy growth accompanying the metal bond. This tendency is remarkable, for example, when the first metal material or the second metal material is solder.

[0032] In the main pressure bonding process, the time during which the temporary pressure bonded body 101 is heated to at least one of the melting point of the first metal material or the melting point of the second metal material may be 60 seconds or less. Alternatively, the time during which the temporary pressure bonded body 101 is heated to at least 220°C in the main pressure bonding process may be 60 seconds or less. According to the main pressure bonding process under these conditions, the metal bonding is easily formed well while suppressing the scattering of the connection part and the formation of voids in the connection part due to excessive alloy growth accompanying the metal bonding. In the main pressure bonding process, the time during which the temporary pressure bonded body 101 is heated to at least one of the melting point of the first metal material or the melting point of the second metal material may be 5 seconds or more. In the main pressure bonding process, the time during which the temporary pressure bonded body 101 is heated to at least 220°C in the main pressure bonding process may be 5 seconds or more.

[0033] Before the temporary pressure-bonded body 101 is heated to the main pressure-bonding temperature, it may be heated in a pressurized atmosphere at a constant preheating temperature lower than the melting point of the first metal material and the melting point of the second metal material. Heating at this preheating temperature may contribute to suppressing voids in the connection part. The time during which the temporary pressure-bonded body 101 is heated at the constant preheating temperature may be 1 minute or more, or 2 minutes or more, and may be 20 minutes or less, or 15 minutes or less. The preheating temperature may be higher than the temporary pressure-bonding temperature, and may be 160°C or more, 165°C or more, or 170°C or more. The preheating temperature may be 200°C or less, 195°C or less, 190°C or less, 185°C or less, or 180°C or less.

[0034] The pressure of the pressurized atmosphere in the heating furnace 50 is set appropriately depending on the size and number of the circuit components, etc. The pressure of the pressurized atmosphere may be, for example, higher than atmospheric pressure and not more than 1 MPa. A higher pressure may contribute, for example, to suppression of voids and improvement of connectivity. A lower pressure may contribute to suppression of fillets. From these viewpoints, the pressure of the pressurized atmosphere may be, for example, higher than atmospheric pressure and not more than 0.90 MPa, or 0.20 MPa or more and not more than 0.80 MPa.

[0035] A plurality of pre-bonded bodies may be heated at the same time in one heating furnace 50. The pre-bonded bodies can be pressurized with high uniformity by the pressurized atmosphere. When the pre-bonded bodies are heated in a pressurized atmosphere, the generation of a fillet, which is an adhesive layer protruding from the outer periphery of the connection body, tends to be suppressed compared to the case where the pre-bonded bodies are heated and pressurized using a pressing member.

[0036] The thermosetting adhesive layer 3 and the thermosetting adhesive that forms it will be described in detail below.

[0037] The thermosetting adhesive layer 3 may be a layer formed from a thermosetting adhesive containing a thermosetting resin having a molecular weight of less than 10,000, a curing agent for the thermosetting resin, and a polymer component having a weight average molecular weight of 10,000 or more.

[0038] Thermosetting resins are compounds that form crosslinked polymers by a curing reaction, examples of which include epoxy resins. Epoxy resins can be compounds having two or more epoxy groups. Examples of epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, naphthalene type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, phenol aralkyl type epoxy resins, biphenyl type epoxy resins, triphenylmethane type epoxy resins, and dicyclopentadiene type epoxy resins. These can be used alone or in combination of two or more. The weight average molecular weight of the epoxy resin is usually less than 10,000. In this specification, the weight average molecular weight means a value measured by gel permeation chromatography (GPC) in terms of standard polystyrene.

[0039] The content of the epoxy resin may be 5% by mass or more and 75% by mass or less, 10% by mass or more and 50% by mass or less, or 15% by mass or more and 35% by mass or less, based on the mass of the thermosetting adhesive layer 3 or the total mass of the components of the thermosetting adhesive other than the solvent.

[0040] The curing agent is a component that promotes the curing reaction of the thermosetting resin. Examples of the curing agent when the thermosetting resin is an epoxy resin include a phenolic resin-based curing agent, an acid anhydride-based curing agent, an amine-based curing agent, an imidazole-based curing agent, and a phosphine-based curing agent. The curing agent may include one or more selected from a phenolic resin-based curing agent, an acid anhydride-based curing agent, an amine-based curing agent, and an imidazole-based curing agent, or may include an imidazole-based curing agent.

[0041] The phenolic resin-based curing agent is a compound having two or more phenolic hydroxyl groups, and examples thereof include phenol novolac, cresol novolac, phenol aralkyl resin, cresol naphthol formaldehyde polycondensate, triphenylmethane type polyfunctional phenol, and other polyfunctional phenol resins. These may be used alone or in combination of two or more.

[0042] The equivalent ratio of the phenolic resin-based curing agent to the epoxy resin (phenolic hydroxyl group / epoxy group, molar ratio) may be 0.3 to 1.5, 0.4 to 1.0, or 0.5 to 1.0, from the viewpoints of good curability, adhesion, and storage stability.

[0043] Examples of the acid anhydride curing agent include methylcyclohexanetetracarboxylic dianhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic dianhydride, and ethylene glycol bisanhydrotrimellitate. These may be used alone or in combination of two or more.

[0044] The equivalent ratio of the acid anhydride curing agent to the epoxy resin (acid anhydride group / epoxy group, molar ratio) may be 0.3 to 1.5, 0.4 to 1.0, or 0.5 to 1.0 from the viewpoint of good curability, adhesion, and storage stability.

[0045] The amine-based curing agent is a compound having an amino group, and examples thereof include dicyandiamide.

[0046] The equivalent ratio of the amine-based curing agent to the epoxy resin (amine / epoxy group, molar ratio) may be 0.3 to 1.5, 0.4 to 1.0, or 0.5 to 1.0, from the viewpoint of good curability, adhesion, and storage stability.

[0047] The imidazole-based curing agent is an imidazole derivative, and examples thereof include 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyano-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4 -diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and adducts of epoxy resins and imidazoles. From the viewpoint of excellent curing property, storage stability and connection reliability, the imidazole-based curing agent may be selected from 1-cyanoethyl-2-undecylimidazole, 1-cyano-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole and 2-phenyl-4-methyl-5-hydroxymethylimidazole. These may be used alone or in combination of two or more. Microcapsules containing these may also be used as a latent curing agent.

[0048] The content of the imidazole-based curing agent may be 0.1 to 20 parts by mass, 0.1 to 10 parts by mass, or 3.2 to 5.5 parts by mass, relative to 100 parts by mass of the epoxy resin.

[0049] Examples of phosphine-based curing agents include triphenylphosphine, tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium tetra(4-methylphenyl)borate, and tetraphenylphosphonium(4-fluorophenyl)borate.

[0050] The content of the phosphine-based curing agent may be 0.1 to 10 parts by mass, or 0.1 to 5 parts by mass, based on 100 parts by mass of the epoxy resin.

[0051] The polymer component may contribute to the heat resistance and film formability of the thermosetting adhesive layer. Examples of the polymer component include phenoxy resin, polyimide resin, polyamide resin, polycarbodiimide resin, cyanate ester resin, acrylic resin, polyester resin, polyethylene resin, polyethersulfone resin, polyetherimide resin, polyvinyl acetal resin, urethane resin, and acrylic rubber. The polymer component may be a copolymer containing a partial structure corresponding to a resin or rubber selected from these. From the viewpoint of heat resistance and film formability, the polymer component may contain one or more selected from phenoxy resin, polyimide resin, acrylic rubber, cyanate ester resin, and polycarbodiimide resin. The polymer component may contain one or more selected from phenoxy resin, polyimide resin, and acrylic rubber. These polymer components may be used alone or in combination of two or more. In this specification, the polymer component is a component different from the above-mentioned thermosetting resin (e.g., epoxy resin).

[0052] The glass transition temperature (Tg) of the polymer component may be 200°C or less, 50°C or more to 200°C or less, 50°C or more to 180°C or less, or 50°C or more to 150°C or less, from the viewpoint of the adhesion of the film-like thermosetting adhesive to the circuit member. If the Tg of the polymer component is 50°C or more, the tack (viscous) force of the thermosetting adhesive tends to be moderately weak. If the Tg of the polymer component is 200°C or less, the thermosetting adhesive tends to properly fill the unevenness due to the connection parts of the circuit member, etc., and as a result, the effect of suppressing voids tends to be relatively large. Here, Tg means a value measured using a DSC (PerkinElmer Co., Ltd., DSC-Pyirs1) under the conditions of a sample amount of 10 mg, a heating rate of 10°C / min, and an air atmosphere.

[0053] The weight average molecular weight of the polymer component may be 30,000 or more, 40,000 or more, or 50,000 or more, and may be 200,000 or less.

[0054] The ratio Ca / Cd (mass ratio) of the epoxy resin content Ca to the polymer component content Cd may be 0.01 to 5, 0.05 to 3, or 0.1 to 2. When the ratio Ca / Cd is 0.01 or more, better curing properties and adhesive strength are easily obtained. When the ratio Ca / Cd is 5 or less, better film formability is easily obtained.

[0055] The thermosetting adhesive layer 3 and the thermosetting adhesive may contain a fluxing agent. The fluxing agent may be, for example, a compound having a group represented by formula (1). The fluxing agent may be a single type of compound represented by formula (1) or a combination of two or more types. [ka] In formula (1), R 1 represents an electron-donating group. Examples of the electron-donating group include an alkyl group, a hydroxyl group, an amino group, an alkoxy group, and an alkylamino group. The electron-donating group may be an alkyl group, a hydroxyl group, or an alkoxyl group, or may be an alkyl group.

[0056] R 1 may be an alkyl group having 1 to 10 carbon atoms or 1 to 5 carbon atoms. The alkyl group may be linear or branched, or may be linear. When the alkyl group is linear, the number of carbon atoms of the alkyl group may be equal to or less than the number of carbon atoms of the main chain containing the carboxylic acid, from the viewpoint of steric hindrance.

[0057] R 1 may be an alkoxy group having 1 to 10 carbon atoms or 1 to 5 carbon atoms. The alkyl group portion of the alkoxy group may be linear or branched, or may be linear. When the alkyl group portion of the alkoxy group is linear, the number of carbon atoms may be equal to or less than the number of carbon atoms of the main chain containing the carboxylic acid, from the viewpoint of steric hindrance.

[0058] R 1 The alkylamino group as the alkylamino group may be, for example, a monoalkylamino group or a dialkylamino group. The number of carbon atoms of the monoalkylamino group may be 1 to 10, or 1 to 5. The alkyl group portion of the monoalkylamino group may be linear or branched, or may be linear. The number of carbon atoms of the dialkylamino group may be 1 to 20, or 1 to 10. The alkyl group portion of the dialkylamino group may be linear or branched, or may be linear.

[0059] The fluxing agent may be a compound having two carboxyl groups (dicarboxylic acid). A compound having two carboxyl groups is less likely to volatilize even at high temperatures during connection compared to a compound having one carboxyl group (monocarboxylic acid), and can further suppress the occurrence of voids. A compound having two carboxyl groups can further suppress the increase in viscosity of the adhesive during storage, connection work, etc. compared to a compound having three or more carboxyl groups. As a result, the connection reliability of the semiconductor device can be further improved.

[0060] The fluxing agent may contain a compound represented by the following formula (2): 1 represents an electron donating group, R 2represents a hydrogen atom or an electron donating group, and n represents an integer of 0 to 10. n may be an integer of 2 to 10, or an integer of 2 to 8. A fluxing agent containing the compound represented by formula (2) can contribute to improving the reflow resistance and connection reliability of a semiconductor device. [ka]

[0061] The fluxing agent may include a compound in which an electron donating group is substituted at the 2-position of a dicarboxylic acid selected from succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, and dodecanedioic acid.

[0062] The melting point of the fluxing agent may be 150°C or less, 140°C or less, or 130°C or less. The melting point of the fluxing agent may be 25°C or more, or 50°C or more. The melting point of the fluxing agent can be measured, for example, by using a device in which a capillary tube filled with a sample is attached to a double-tube thermometer and heated in a hot bath. The melting point of the fluxing agent may be higher than the temporary bonding temperature for forming the temporary bonded body.

[0063] The content of the fluxing agent may be 0.5 to 10 mass %, or 0.5 to 5 mass %, based on the mass of the thermosetting adhesive layer 3 or the total mass of the components of the thermosetting adhesive other than the solvent.

[0064] The thermosetting adhesive layer 3 and the thermosetting adhesive may further comprise a filler. The filler can be an inorganic filler, an organic filler, or a combination thereof.

[0065] Examples of inorganic fillers include glass, silica, alumina, titanium oxide, carbon black, mica, and boron nitride. The inorganic filler may be one or more selected from silica, alumina, titanium oxide, and boron nitride, or silica, alumina, and boron nitride. The filler may be whiskers, examples of which include aluminum borate, aluminum titanate, zinc oxide, calcium silicate, magnesium sulfate, and boron nitride.

[0066] The organic filler may be a resin filler, examples of which include particles containing a resin selected from polyurethane, polyimide, methyl methacrylate resin, and methyl methacrylate-butadiene-styrene copolymer resin (MBS).

[0067] The filler content may be 30 to 90 mass %, 30 to 80 mass %, or 30 to 50 mass % based on the mass of the thermosetting adhesive layer 3 or the total mass of components of the thermosetting adhesive other than the solvent.

[0068] The thermosetting adhesive layer 3 and the thermosetting adhesive may further contain other components such as an ion trapper, an antioxidant, a silane coupling agent, a titanium coupling agent, and a leveling agent, etc. These may be used alone or in combination of two or more.

[0069] The thermosetting adhesive for forming the thermosetting adhesive layer 3 may further contain a solvent for dissolving or dispersing each component. A film-like thermosetting adhesive can be produced by applying a thermosetting adhesive (resin varnish) containing a solvent to a substrate film and drying the coating.

[0070] The solvent used in preparing the resin varnish is selected from those capable of uniformly dissolving or dispersing each component. The solvent can be an organic solvent, examples of which include dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, dimethylsulfoxide, diethylene glycol dimethyl ether, toluene, benzene, xylene, methyl ethyl ketone, tetrahydrofuran, ethyl cellosolve, ethyl cellosolve acetate, butyl cellosolve, dioxane, cyclohexanone, and ethyl acetate. These organic solvents can be used alone or in combination of two or more.

[0071] Examples of the base film include polyolefin films such as polypropylene film and polymethylpentene film, polyester films such as polyethylene terephthalate film and polyethylene naphthalate film, polyimide film, and polyetherimide film. The base film may be a single layer film made of these films, or a multilayer film made of two or more types of films.

[0072] When the thermosetting adhesive layer 3 has high fluidity near the onset temperature, good electrical conduction is easily ensured. Therefore, the thermosetting adhesive layer 3 may have a shear viscosity of 10,000 Pa·s or less, 9,000 Pa·s or less, 8,000 Pa·s or less, 7,000 Pa·s or less, 6,000 Pa·s or less, 5,000 Pa·s or less, 4,000 Pa·s or less, 3,000 Pa·s or less, or 2,000 Pa·s or less at a temperature 20°C lower than the onset temperature. The thermosetting adhesive layer 3 may have a shear viscosity of 500 Pa·s or more, or 1,000 Pa·s or more at a temperature 20°C lower than the onset temperature.

[0073] The shear viscosity of the thermosetting adhesive layer 3 at 40° C. may be 10,000 Pa·s or more, 200,000 Pa·s or less, or 150,000 Pa·s or less.

[0074] The minimum shear viscosity (minimum melt viscosity) of the thermosetting adhesive layer 3 may be 500 Pa·s or more and 3000 Pa·s or less, or 800 Pa·s or more and 2500 Pa·s or less. When the minimum melt viscosity of the thermosetting adhesive layer 3 is in this range, voids tend not to remain in the adhesive layer. Also, in the temporary pressure bonding step, the thermosetting adhesive tends to be sufficiently removed from between the connection parts.

[0075] The shear viscosity of the thermosetting adhesive layer 3 at each temperature and the minimum value of the shear viscosity can be values ​​read from a viscosity curve showing the relationship between the shear viscosity (complex viscosity) and temperature obtained when the viscoelasticity of a sample of the thermosetting adhesive layer 3 is measured under conditions of a heating rate of 10°C / min, a frequency of 10 Hz, and a strain of 1%. The sample for the viscoelasticity measurement may be, for example, a laminate having a thickness of 300 to 450 μm obtained by laminating a plurality of thermosetting adhesive layers. The viscosity measuring device may be, for example, ARES manufactured by TA Instruments.

[0076] The shear viscosity of the thermosetting adhesive layer 3 can be adjusted within a desired range, for example, by adjusting the type and content of the polymer component or filler.

[0077] The gel time of the thermosetting adhesive layer 3 may be 10 seconds or more and 30 seconds or less at 200°C. Having the gel time in this range can contribute to suppressing remaining voids and improving connection reliability. The gel time is the time from when the thermosetting adhesive layer 3 is placed on a hot plate at 200°C until the thermosetting adhesive layer 3 gels. The gel time of the thermosetting adhesive layer 3 can be adjusted by the type and content of the curing agent, etc. EXAMPLES

[0078] The present invention is not limited to the following examples. 1. Raw materials (a) Epoxy resin - Multifunctional solid epoxy resin with triphenolmethane structure (EP1032H60, manufactured by Mitsubishi Chemical Corporation, weight average molecular weight: 800-2000) Bisphenol F type liquid epoxy resin (YL983U, manufactured by Mitsubishi Chemical Corporation, molecular weight: approx. 336) Flexible semi-solid epoxy resin (YX7110B80, manufactured by Mitsubishi Chemical Corporation, weight average molecular weight: 1000-5000) (b) Hardener 2,4-Diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct (2MAOK-PW, manufactured by Shikoku Kasei Co., Ltd.) (c) Polymer component Phenoxy resin (FX-293, Nippon Steel Chemical & Material Co., Ltd., Tg: approx. 160°C, weight average molecular weight: 40,000-50,000) (d) Fluxing agent Glutaric acid (Tokyo Chemical Industry Co., Ltd., melting point: approx. 98°C) (e) Fila Inorganic Filler Silica filler (SE2030, manufactured by Admatechs Co., Ltd., average particle size: 500 nm) Epoxy silane surface-treated silica filler (SE2030, manufactured by Admatechs Co., Ltd., average particle size: approx. 500 nm) Methacrylic surface-treated nano-silica filler (YA050C, manufactured by Admatechs Co., Ltd., average particle size: approx. 50 nm) Organic Filler Resin filler (EXL-2655, Dow Chemical Japan, core-shell type organic fine particles)

[0079] 2. Preparation of film-type thermosetting adhesive A resin varnish containing the raw materials in the ratios (parts by mass) shown in Table 1 was applied to a base film and the coating was dried to produce two types of film-like thermosetting adhesives A and B (thickness 40 μm).

[0080] DSC (Differential Scanning Calorimetry) For the thermosetting adhesive A or B, DSC was measured under the following conditions. Sample size: 10mg Heating rate: 10℃ / min Air or nitrogen atmosphere The onset temperature, peak temperature, and heat generation amount were determined for the exothermic peak that showed the largest heat generation amount in the obtained DSC curve. Thermosetting adhesives A and B showed an integrated exothermic peak including two maximum points. The onset temperature was determined as the temperature at the intersection of the tangent to the curve at the position where the gradient of the exothermic peak curve is maximum on the lower temperature side of the two maximum points of the exothermic peak and the extension of the baseline of the DSC curve. The peak temperature is the temperature at the highest of the two maximum points.

[0081] Response rate Thermosetting adhesives A and B were heated at 150°C or 170°C for 30 seconds. After heating, the thermosetting adhesives were measured for DSC under the same conditions as above, and the heat generation amount Q1 of the exothermic peak was calculated. The reaction rate was calculated from Q1 and the heat generation amount Q0 of the thermosetting adhesive before heating using the following formula. Response rate (%) = {(Q0-Q1) / Q0} x 100

[0082] Shear Viscosity The thermosetting adhesive was laminated with a laminator to form a laminate with a thickness of 500 μm or more. A measurement sample having a size of 10.0 mm × 10.0 mm was cut out from the laminate. The shear viscosity (viscosity coefficient) of the measurement sample was measured under the following conditions using a viscoelasticity measuring device (product name: ARES-G2, manufactured by TA Instruments). From the viscosity curve showing the relationship between shear viscosity and temperature, the shear viscosity and the minimum value of melt viscosity (minimum melt viscosity) at 40°C, 80°C, 130°C, 150°C, or 160°C were obtained. Table 1 also shows the temperature at which the minimum melt viscosity was shown. Mode: Shear Heating rate: 10℃ / min Frequency: 10Hz Distortion: 1%

[0083] [Table 1]

[0084] 3. Manufacturing of semiconductor devices Temporary pressure bonding process The following first and second semiconductor chips were prepared. First semiconductor chip: A semiconductor chip with connections consisting of Cu pillars and solder bumps (melting point: approximately 217°C) containing Sn-Ag alloy provided on the Cu pillars, arranged at different pitches along the periphery and inside the chip body (size: 7.3 mm square, thickness: 50 μm, total height of Cu pillars and Sn-Ag solder: approximately 45 μm, number of bumps: 1048 pins, bump pitch along periphery: 80 μm, inner bump pitch: 300 μm, product name: WALTS-TEG CC80, manufactured by Waltz Corporation) Second semiconductor chip A second semiconductor chip (chip size: 10mm square, thickness: 100μm, product name: WALTS-TEG IP80, manufactured by Waltz Corporation) with connections made of Ni-plated Au (melting point: approx. 1065℃) arranged at different pitches along the outer periphery and inside of the chip body.

[0085] A film-like thermosetting adhesive A or B cut into a size of 7.3 mm square was attached to the connection surface of the first semiconductor chip. The first semiconductor chip to which the thermosetting adhesive was attached was picked up by the pressure head of a flip chip bonder (FCB3, manufactured by Panasonic Corporation). The picked up first semiconductor chip was placed on the second semiconductor chip placed on the stage in such a direction that the thermosetting adhesive was sandwiched between the first semiconductor chip and the second semiconductor chip, and the resulting laminate was heated and pressed by the pressure head of the flip chip bonder, thereby obtaining a temporary pressure-bonded body. A temporary pressure-bonded body was produced under several conditions of temperature, time, and pressure shown in Table 2. The temperature is the set temperature of the pressure head, and the pressure is the load applied to the entire first semiconductor chip by the pressure head.

[0086] Main crimping process Each pre-bonded body was heated in a heating furnace (pressurized reflow device, VPF300HP, manufactured by Synapex Co., Ltd.) under a pressurized atmosphere of 0.8 MPa to form a connection body (semiconductor device) for evaluation having a first semiconductor chip and a second semiconductor chip. The temperature of the pressurized atmosphere was changed under the following temperature conditions C1 or C2. C1: Heat up at 3℃ / sec and hold at 260℃ (bonding temperature) for 10 minutes (time at temperature above the melting point of solder containing Sn-Ag alloy: approx. 630 seconds) C2: Heat up at 3°C / sec, hold at 175°C (preheating temperature) for 10 minutes, heat up at 3°C / sec, and hold at 230°C (final bonding temperature) for 0.1 seconds (time at temperature above the melting point of solder containing Sn-Ag alloy: approx. 30 seconds)

[0087] 4. Evaluation (1) Connectivity Continuity The electrical continuity between the connections of the temporary crimped body and the connection body was measured using a digital multimeter (CDM-09N, manufactured by Custom Co., Ltd.). OK: Continuity is confirmed at the connection on the inner circumference. NG: No continuity was found at the connection on the inner circumference.

[0088] Solder condition The cross section of the connection was observed with an SEM (scanning electron microscope SU1510, manufactured by Hitachi High-Technologies Corporation). The state of the solder on the cross section of the connection was evaluated according to the following criteria. A: No defects or voids B: Defects or voids present; C: Solder crush D: Poor connection (connections are not touching each other) Fig. 5 is a photograph of a connection in the connection body of Example 4, in which the solder state was A. Fig. 6 is a photograph of a connection in the connection body of Example 2, in which the solder state was B. Fig. 7 is a photograph of a connection in the connection body of Comparative Example 2, in which the solder state was C. Fig. 8 is a photograph of a connection in the connection body of Comparative Example 1, in which the solder states were C and D.

[0089] (2) Void The state of remaining voids inside the connections after this bonding was evaluated using SAM (ultrasonic digital imaging diagnostic device IS-350, manufactured by Insight Co., Ltd.) It was confirmed that the voids had been properly removed in all connections.

[0090] [Table 2]

[0091] As shown in Table 2, it was confirmed that by combining the pre-bonding process, which involves heating to a pre-bonding temperature above the onset temperature, and the main bonding process, which involves pressurization in a pressurized atmosphere at a low pressure of 1.50 MPa or less, it is possible to suppress deformation of the connection (solder crushing) while ensuring good conductivity. [Explanation of symbols]

[0092] 1...first circuit member, 2...second circuit member, 3...thermosetting adhesive layer, 11...metal pillar, 12...bump, 15...first connecting portion, 25...second connecting portion, 41, 42...pressing member, 50...heating furnace, 100...laminated body, 101...temporarily pressure-bonded body, 102...connecting body (semiconductor device).

Claims

1. a laminate including a first circuit member having a first connection portion including a first metal material, a second circuit member having a second connection portion including a second metal material, and a thermosetting adhesive layer, the thermosetting adhesive layer being interposed between the first circuit member and the second circuit member, the laminate being heated and pressurized by a pair of opposing pressing members, thereby forming a temporary pressure-bonded body in which the first connection portion and the second connection portion are in contact with each other; Heating the temporary pressure-bonded body to a predetermined full pressure-bonding temperature under a pressurized atmosphere, thereby forming a connection body in which the first connection portion and the second connection portion are electrically connected by metal bonding between the first metal material and the second metal material; A method for manufacturing a semiconductor device, comprising: The first circuit member is a semiconductor chip or a semiconductor wafer, and the second circuit member is a wiring circuit board, a semiconductor chip, or a semiconductor wafer; The laminate is pressed by the pair of pressing members at a predetermined pressure of 1.50 MPa or less, During a part or the whole of the time during which the laminate is heated and pressurized by the pair of pressing members, at least one of the pair of pressing members is heated to a predetermined temporary pressure-bonding temperature, and the temporary pressure-bonding temperature is a temperature that is equal to or higher than an onset temperature of the thermosetting adhesive layer and is lower than the main pressure-bonding temperature, the onset temperature is the onset temperature of an exothermic peak exhibiting the largest amount of heat generation in a DSC curve obtained by differential scanning calorimetry under conditions in which a sample of the thermosetting adhesive layer is heated at a temperature increase rate of 10° C. / min; The main compression bonding temperature is a temperature equal to or higher than at least one of the melting point of the first metal material and the melting point of the second metal material. method.

2. The method of claim 1 , wherein the predetermined pressure is equal to or greater than 0.94 MPa and equal to or less than 1.50 MPa.

3. The method according to claim 1 , wherein the temporary compression temperature is equal to or higher than the onset temperature and equal to or lower than 200° C.

4. The method according to claim 1 , wherein the laminate is heated and pressed by the pair of pressing members for a period of 5 seconds or less.

5. 2. The method of claim 1, wherein the thermosetting adhesive layer exhibits a shear viscosity of 10,000 Pa·s or less at a temperature 20° C. lower than the onset temperature, the shear viscosity being measured under conditions of a heating rate of 10° C. / min, a frequency of 10 Hz, and a strain of 1%.

6. The method according to claim 1 , wherein the time during which the pre-bonded body is heated to at least one of the melting point of the first metal material and the melting point of the second metal material under the pressurized atmosphere is 60 seconds or less.

7. The method according to claim 1 , wherein the pressure of the pressurized atmosphere is greater than atmospheric pressure and is equal to or less than 0.90 MPa.

8. The thermosetting adhesive layer is a thermosetting resin having a molecular weight of less than 10,000; A curing agent for the thermosetting resin; A polymer component having a weight average molecular weight of 10,000 or more; The method of claim 1 , comprising:

9. The method of claim 8, wherein the polymeric component has a glass transition temperature of 200° C. or less.

10. The method of claim 1 , wherein the thermosetting adhesive layer exhibits a shear viscosity of 10,000 Pa·s or greater at 40° C.

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