Semiconductor device manufacturing method

Abstract

To form a resist pattern from a resist film including a metal oxide photoresist material with a smaller number of steps.SOLUTION: A method for manufacturing a semiconductor device includes the steps of: temporarily crimping a first member having a connecting portion and a second member having a connecting portion via an adhesive at a temperature lower than the melting point of the connecting portion of the first member and the melting point of the connecting portion of the second member, thereby obtaining a temporary crimped body in which the connecting portion of the first member and the connecting portion of the second member are arranged to face each other; and heating the temporary crimped body to a temperature equal to or higher than the melting point of at least one of the connecting portion of the first member and the connecting portion of the second member while being pressurized by atmospheric pressure, thereby bonding the connecting portions arranged to face each other so that they are electrically connected to each other. The first member is a semiconductor chip or a semiconductor wafer, and the second member is a printed circuit board, a semiconductor chip, or a semiconductor wafer.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a semiconductor device and a manufacturing method thereof. [Background technology]

[0002] Conventionally, when connecting a semiconductor chip to a substrate, the wire bonding method using thin metal wires such as gold wires has been widely used.

[0003] In recent years, in order to meet the demands for high functionality, high integration, high speed, etc. for semiconductor devices, the flip chip connection method (FC connection method) in which conductive protrusions called bumps are formed on a semiconductor chip or substrate to directly connect the semiconductor chip to the substrate is becoming widespread.

[0004] Known flip chip connection methods include a method of metal-bonding the connection parts using solder, tin, gold, silver, copper, etc., a method of metal-bonding the connection parts by applying ultrasonic vibrations, a method of maintaining mechanical contact by the contraction force of resin, etc. From the viewpoint of the reliability of the connection parts, a method of metal-bonding the connection parts using solder, tin, gold, silver, copper, etc. is common.

[0005] For example, in the connection between a semiconductor chip and a substrate, the COB (Chip On Board) type connection method that is widely used for BGA (Ball Grid Array) and CSP (Chip Size Package) is also an FC connection method.

[0006] Higher functionality is strongly required for area array type semiconductor packages used in CPUs, MPUs, etc. For this reason, there is a trend toward larger chips, an increase in the number of pins (bumps, wiring), and higher density pitches and gaps.

[0007] The FC connection method is also widely used in COC (Chip On Chip) type connection methods in which bumps or wiring are formed on semiconductor chips to connect between semiconductor chips.

[0008] Additionally, chip-stack packages that utilize the above-mentioned connection methods in multiple stages, such as POP (Package On Package) and TSV (Through-Silicon Via), are becoming more widespread. These technologies can make packages smaller by arranging semiconductor chips three-dimensionally rather than flatly, which allows for the pursuit of even smaller, thinner, and more functional semiconductor devices.

[0009] These technologies are effective in improving semiconductor performance, reducing noise, reducing mounting area, and saving power, and are attracting attention as next-generation semiconductor wiring technologies.

[0010] Also, from the perspective of improving productivity, attention is being paid to chip-on-wafer (COW), in which semiconductor chips are connected on a wafer and then diced to create semiconductor packages, and wafer-on-wafer (WOW), in which wafers are pressure-bonded together and then diced to create semiconductor packages (see, for example, Patent Document 1).

[0011] Furthermore, from the viewpoint of improving productivity, gang bonding, in which multiple chips are aligned on a wafer or a map substrate and temporarily pressure-bonded to the substrate, and multiple chips are pressure-bonded together to ensure connection, is also attracting attention.

[0012] In assembling the above-mentioned flip chip connection package, first, a semiconductor chip or a semiconductor chip to which a semiconductor adhesive has been applied is picked up from a diced wafer by a collet and supplied to a pressure bonding tool via the collet. Next, the chip-chip or chip-substrate is aligned and then pressure bonded. During pressure bonding, the temperature of the pressure bonding tool is raised so that the metal of one or both of the connection parts reaches the melting point or higher so that a metal bond is formed. After that, the high-temperature pressure bonding tool is cooled, and the semiconductor chip is picked up again by the pressure bonding tool. If the semiconductor adhesive has been applied on the semiconductor chip, the pressure bonding tool adsorbs the surface of the semiconductor chip opposite to the surface to which the semiconductor adhesive has been applied (the surface to be connected) and picks up the semiconductor chip. In this case, it is necessary to cool the pressure bonding tool from a high temperature at which the metal of the connection part melts to a low temperature at which the semiconductor chip to which the semiconductor adhesive has been applied can be picked up. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] JP 2008-294382 A Summary of the Invention [Problem to be solved by the invention]

[0014] In the flip-chip connection method, in which connections are secured by heating the connection part to above the melting point of the metal, the crimping tool is at a high temperature immediately after crimping (for example, 240°C or higher for solder). If the semiconductor chip is picked up from the collet without cooling the hot crimping tool, the heat from the crimping tool is transferred to the collet, causing the temperature of the collet itself to rise, resulting in malfunctions and reduced productivity.

[0015] In a semiconductor chip to which a semiconductor adhesive is applied, when the temperature of the semiconductor adhesive rises and viscosity appears due to the heat of the bonding tool being transferred to the collet, the semiconductor adhesive adheres to the collet, and productivity decreases. Even in the case of only semiconductor chips, if the collet becomes too hot, when picking up individual semiconductor chips from the dicing tape, heat is transferred to the dicing tape via the collet, which reduces the pick-up ability and decreases productivity.

[0016] It is believed that the above problems can be avoided by separating the process of pre-bonding at a temperature lower than the melting point of the metal of the connection part from the process of heat treatment at a temperature equal to or higher than the melting point of the metal. However, the inventors' investigations have revealed that this method does not remove voids generated in the pre-bonding process, which may lead to a decrease in reliability.

[0017] SUMMARY OF THE PRESENT EMBODIMENT An object of one aspect of the present invention is to provide a method for manufacturing a semiconductor device that can simultaneously suppress voids and ensure connections. [Means for solving the problem]

[0018] One aspect of the present invention is to solve the above-mentioned problems, and provides a method for manufacturing a semiconductor device, comprising the steps of: temporarily bonding a first member having a connection portion and a second member having a connection portion via an adhesive at a temperature lower than the melting point of the connection portion of the first member and the melting point of the connection portion of the second member to obtain a temporarily bonded body in which the connection portion of the first member and the connection portion of the second member are arranged opposite to each other; and heating the temporarily bonded body to a temperature equal to or higher than the melting point of at least one of the connection portion of the first member or the connection portion of the second member while pressurizing the temporarily bonded body by air pressure, thereby joining the oppositely arranged connection portions so as to be electrically connected to each other. The first member is a semiconductor chip or a semiconductor wafer, and the second member is a wiring circuit board, a semiconductor chip, or a semiconductor wafer.

[0019] By separately performing a process of pre-bonding the first member such as a picked-up semiconductor chip at a low temperature and a process of main bonding in which the connecting parts arranged opposite each other are electrically connected, the cooling time and the cooling process of the bonding tool can be omitted, and productivity is improved compared to a case in which the pre-bonding process is not provided. Furthermore, by performing the main bonding while applying pressure by air pressure, voids remaining in the adhesive after the pre-bonding can be efficiently removed.

[0020] The adhesive may contain a thermosetting resin having a weight average molecular weight of less than 10,000 and a curing agent thereof. The adhesive may further contain a polymer component having a weight average molecular weight of 10,000 or more. The weight average molecular weight of the polymer component may be 30,000 or more. The glass transition temperature of the polymer component may be 100° C. or less. The adhesive may be a film-like adhesive. Effect of the Invention

[0021] According to one aspect of the present invention, there is provided a method for manufacturing a semiconductor device, which is capable of suppressing voids while ensuring connections. The method of the present invention is also excellent in that it can manufacture a large number of highly reliable semiconductor devices in a short period of time. [Brief description of the drawings]

[0022] [Figure 1] 1 is a cross-sectional view showing an embodiment of a semiconductor device. [Diagram 2] 1 is a cross-sectional view showing an embodiment of a semiconductor device. [Diagram 3] 1 is a cross-sectional view showing an embodiment of a semiconductor device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Hereinafter, several embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

[0024] (Semiconductor Device) 1, 2 and 3 are cross-sectional views showing an embodiment of a semiconductor device that can be manufactured by a method according to an embodiment described below.

[0025] FIG. 1 is a schematic cross-sectional view showing a COB-type connection between a semiconductor chip and a substrate. The semiconductor device 100 shown in FIG. 1(a) includes a semiconductor chip 1, a substrate 2 (wired circuit board), and an adhesive layer 40 interposed therebetween. In the case of the semiconductor device 100, the semiconductor chip 1 has a semiconductor chip body 10, wiring 15 arranged on the surface of the semiconductor chip body 10 facing the substrate 2, and bumps 30 arranged on the wiring 15 as connecting parts. The substrate 2 has a substrate body 20 and wiring 16 arranged on the surface of the substrate body 20 facing the semiconductor chip 1 as connecting parts. The bumps 30 of the semiconductor chip 1 and the wiring 16 of the substrate 2 are electrically connected by metal bonding. The semiconductor chip 1 and the substrate 2 are flip-chip connected by the wiring 16 and the bumps 30. The wirings 15, 16, and the bumps 30 are sealed by the adhesive layer 40 and are thus isolated from the external environment.

[0026] The semiconductor device 200 shown in FIG. 1(b) includes a semiconductor chip 1, a substrate 2, and an adhesive layer 40 interposed therebetween. In the case of the semiconductor device 200, the semiconductor chip 1 has bumps 32 arranged on the surface of the semiconductor chip 1 facing the substrate 2 as connecting parts. The substrate 2 has bumps 33 arranged on the surface of the substrate body 20 facing the semiconductor chip 1 as connecting parts. The bumps 32 of the semiconductor chip 1 and the bumps 33 of the substrate 2 are electrically connected by metal bonding. The semiconductor chip 1 and the substrate 2 are flip-chip connected by the bumps 32, 33. The bumps 32, 33 are sealed by the adhesive layer 40 and are thus isolated from the external environment.

[0027] Fig. 2 shows a COC type connection between semiconductor chips. The configuration of a semiconductor device 300 shown in Fig. 2(a) is similar to that of the semiconductor device 100, except that two semiconductor chips 1 are flip-chip connected via wiring 15 and bumps 30. The configuration of a semiconductor device 400 shown in Fig. 2(b) is similar to that of the semiconductor device 200, except that two semiconductor chips 1 are flip-chip connected via bumps 32.

[0028] 1 and 2, the connection parts such as the wiring 15 and the bumps 32 may be metal films (e.g., gold plating) called pads, or may be post electrodes (e.g., copper pillars). For example, in (b) of FIG. 2, in an embodiment in which one semiconductor chip has a copper pillar and a connection bump (solder: tin-silver) as a connection part and the other semiconductor chip has a gold plating as a connection part, when the connection part reaches a temperature equal to or higher than the melting point of the solder with the lowest melting point among the metal materials of the connection part, the solder melts to form a metal bond between the connection parts, and electrical connection between the connection parts becomes possible.

[0029] The semiconductor chip body 10 is not particularly limited, and various semiconductors can be used, such as elemental semiconductors composed of the same type of element, such as silicon and germanium, and compound semiconductors, such as gallium arsenide and indium phosphide.

[0030] The substrate 2 is not particularly limited as long as it is a wired circuit board, and examples that can be used include a circuit board in which wiring (wiring pattern) is formed by etching away unnecessary portions of a metal layer formed on the surface of an insulating substrate whose main component is glass epoxy, polyimide, polyester, ceramic, epoxy, bismaleimide triazine, etc., a circuit board in which wiring (wiring pattern) is formed on the surface of the insulating substrate by metal plating or the like, and a circuit board in which wiring (wiring pattern) is formed by printing a conductive material on the surface of the insulating substrate.

[0031] The materials of the connecting parts such as the wirings 15 and 16, the bumps 30, and the bumps 32 and 33 are mainly composed of gold, silver, copper, solder (the main components are, for example, tin-silver, tin-lead, tin-bismuth, tin-copper, tin-silver-copper), tin, nickel, etc., and may be composed of only a single component or a plurality of components. The connecting parts may have a structure in which these metals are laminated. Of the metal materials, copper and solder are relatively inexpensive and are preferable. From the viewpoint of improving the connection reliability and suppressing warping, the connecting parts may contain solder.

[0032] The material of the pad is mainly composed of gold, silver, copper, solder (main components are, for example, tin-silver, tin-lead, tin-bismuth, tin-copper, tin-silver-copper), tin, nickel, etc., and may be composed of only a single component or a plurality of components. The pad may have a structure in which these metals are laminated. From the viewpoint of connection reliability, the pad may contain gold or solder.

[0033] A metal layer mainly composed of gold, silver, copper, solder (main components are, for example, tin-silver, tin-lead, tin-bismuth, tin-copper), tin, nickel, etc. may be formed on the surface of the wiring 15, 16 (wiring pattern). This metal layer may be composed of only a single component, or may be composed of multiple components. The metal layer may have a structure in which multiple metal layers are stacked. The metal layer may contain relatively inexpensive copper or solder. From the viewpoint of improving connection reliability and suppressing warping, the metal layer may contain solder.

[0034] Semiconductor devices (packages) such as those shown in FIG. 1 or 2 may be stacked and electrically connected with gold, silver, copper, solder (main components are, for example, tin-silver, tin-lead, tin-bismuth, tin-copper, tin-silver-copper), tin, nickel, or the like. The metal for connection may be relatively inexpensive copper or solder. For example, as seen in TSV technology, an adhesive layer may be interposed between semiconductor chips, and flip-chip connection or stacking may be performed, and holes penetrating the semiconductor chips may be formed to connect to electrodes on the pattern surface.

[0035] FIG. 3 is a cross-sectional view showing another embodiment of the semiconductor device (semiconductor chip stacking type embodiment (TSV)). In the semiconductor device 500 shown in FIG. 3, the wiring 15 formed on the interposer body 50 as a substrate is connected to the bumps 30 of the semiconductor chip 1, thereby flip-chip connecting the semiconductor chip 1 and the interposer 5. An adhesive layer 40 is interposed between the semiconductor chip 1 and the interposer 5. On the surface of the semiconductor chip 1 opposite to the interposer 5, the semiconductor chips 1 are repeatedly stacked via the wiring 15, the bumps 30 and the adhesive layer 40. The wiring 15 on the pattern surfaces on the front and back of the semiconductor chip 1 are connected to each other by the through electrodes 34 filled in the holes penetrating the inside of the semiconductor chip body 10. The material of the through electrodes 34 can be copper, aluminum, or the like.

[0036] Such TSV technology allows signals to be obtained from the back surface of the semiconductor chip, which is not normally used. Furthermore, since the through electrodes 34 are vertically passed through the semiconductor chip 1, the distance between the opposing semiconductor chips 1 and between the semiconductor chip 1 and the interposer 5 can be shortened, enabling flexible connection. In such TSV technology, the adhesive layer can be used as a sealing material between the opposing semiconductor chips 1 and between the semiconductor chip 1 and the interposer 5.

[0037] (Method of manufacturing a semiconductor device) One embodiment of the method for manufacturing a semiconductor device includes a first step (temporary bonding step) of temporarily bonding a first member having a connection portion and a second member having a connection portion via an adhesive at a temperature lower than the melting point of the connection portion of the first member and the melting point of the connection portion of the second member to obtain a temporary compression body in which the connection portion of the first member and the connection portion of the second member are arranged opposite to each other, and a second step (full compression bonding step) of heating the temporary compression body to a temperature equal to or higher than the melting point of the oppositely arranged connection portions while pressurizing the temporary compression body by air pressure, thereby joining the oppositely arranged connection portions so as to be electrically connected to each other. The first member is a semiconductor chip or a semiconductor wafer, and the second member is a wiring circuit board, a semiconductor chip, or a semiconductor wafer.

[0038] In the temporary pressure-bonding step, for example, the semiconductor chips separated from the dicing tape are picked up and adsorbed to a pressure-bonding tool (pressure-bonding head) of a pressure-bonding machine, and temporarily pressure-bonded to a wiring circuit board, another semiconductor chip, or a semiconductor wafer. Alternatively, a semiconductor wafer may be temporarily pressure-bonded to another semiconductor wafer.

[0039] Before the temporary pressure bonding, for example, a film-like adhesive is applied onto a semiconductor chip or a semiconductor wafer as a first member. The application can be performed by hot pressing, roll lamination, vacuum lamination, or the like. The area and thickness of the applied film-like adhesive are appropriately set depending on the size of the semiconductor chip or substrate, the height of the connection portion (bump), and the like. The film-like adhesive may be applied to the semiconductor chip, or the semiconductor wafer to which the film-like adhesive is applied may be diced and then separated into individual semiconductor chips.

[0040] In the temporary bonding process, alignment is required to electrically connect the connection parts, so a bonding machine such as a flip chip bonder is generally used.

[0041] When the bonding tool picks up the semiconductor chip for temporary bonding, the bonding tool is preferably at a low temperature so that heat is not transferred to the semiconductor adhesive on the semiconductor chip. On the other hand, during temporary bonding, the semiconductor chip is preferably heated to a high temperature so that the fluidity of the adhesive can be increased and the voids involved can be efficiently eliminated. However, heating at a temperature lower than the reaction start temperature of the adhesive is preferable. In order to shorten the cooling time, it is preferable that the difference between the temperature of the bonding tool when picking up the semiconductor chip and the temperature of the bonding tool when temporary bonding is small. This temperature difference is preferably 100°C or less, more preferably 60°C or less, and even more preferably substantially 0°C. If the temperature difference is 100°C or more, it takes time to cool the bonding tool, so productivity tends to decrease. The reaction start temperature of the adhesive refers to the onset temperature 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 or nitrogen atmosphere.

[0042] The load applied for temporary pressure bonding is appropriately set in consideration of the number of connection parts (bumps), the absorption of height variations of the connection parts (bumps), and the control of the deformation amount of the connection parts (bumps). It is preferable that the opposing connection parts are in contact with each other after temporary pressure bonding. If the connection parts are in contact with each other after temporary pressure bonding, metal bonds of the connection parts are easily formed in the main pressure bonding, and there is a tendency for the adhesive to be less bitten in. The load for temporary pressure bonding is preferably large in order to eliminate voids and to bring the connection parts into contact, and is preferably 0.009 N to 0.2 N per connection part (e.g., bump).

[0043] From the viewpoint of improving productivity, the pre-press bonding step is preferably performed for a shorter period of time, and may be, for example, 5 seconds or less, 3 seconds or less, or 2 seconds or less.

[0044] The pre-bonding step is followed by a full bonding step in which the opposing connection parts are joined by metallic bonding and the gap between the connection parts is usually filled with an adhesive. The full bonding step is carried out using a device that can heat the connection parts to above the melting point of the metal and can apply pressure by air pressure. Examples of such devices include a pressurized reflow furnace and a pressurized oven.

[0045] The heating temperature for the main pressure bonding should be equal to or higher than the melting point of at least one of the metals of the opposing connection parts (e.g., bump-bump, bump-pad, bump-wiring). For example, when the metal of the connection part is solder, the temperature is preferably 220°C or higher and 330°C or lower. If the temperature of the main pressure bonding is low, the metal of the connection part may not melt, and sufficient metal bonding may not be formed. If the temperature of the main pressure bonding is excessively high, the effect of void suppression may become relatively small, or the solder may easily splash.

[0046] The heating temperature in the main pressure bonding process is preferably higher than the reaction start temperature of the adhesive. By promoting the hardening of the adhesive as well as the formation of the metal bond of the connection during the main pressure bonding, more excellent effects can be obtained in terms of void suppression and connectivity. If the pressure bonding process is performed using a pressure bonding machine, the heat of the pressure bonding machine is not easily transmitted to the adhesive (fillet) protruding from the side of the connection, so that a heat treatment is often required after the main pressure bonding process to sufficiently advance the hardening of the adhesive. In contrast, if pressure is applied by air pressure in a pressure reflow oven, pressure oven, etc. instead of a pressure bonding machine, heat can be applied to the entire body, and the heat treatment after the main pressure bonding can be shortened or eliminated, improving productivity. In addition, if pressure is applied by air pressure, it is easy to perform the main pressure bonding of multiple temporary pressure bonding bodies at once. Furthermore, pressure by air pressure is preferable from the viewpoint of fillet suppression rather than direct pressure using a pressure bonding machine. Fillet suppression is important for the trend toward miniaturization and high density of semiconductor devices.

[0047] The atmosphere in which the full-pressure bonding is carried out is not particularly limited, but an atmosphere containing air, nitrogen, formic acid, or the like is preferable.

[0048] The pressure for the main bonding is appropriately set depending on the size and number of the members to be connected. The pressure for the main bonding may be, for example, higher than atmospheric pressure and 1 MPa or less. A higher pressure is preferable from the viewpoint of suppressing voids and improving connectivity, and a lower pressure is preferable from the viewpoint of suppressing fillets. Therefore, the pressure for the main bonding is more preferably 0.05 to 0.5 MPa.

[0049] When multiple semiconductor chips are stacked three-dimensionally, such as in a semiconductor device with a TSV structure, the multiple semiconductor chips may be stacked one by one and temporarily bonded together, and then the stacked semiconductor chips may be heated and pressurized together to perform the final bonding.

[0050] Between the temporary bonding step and the main bonding step, a step of applying pressure to the temporary bonding body while heating it to a temperature equal to or higher than the melting point of the metal of the connection part (a temperature of 230°C or higher in the case of solder) by a pressure bonding machine (pressure bonding tool) may be added from the viewpoint of improving productivity. From the viewpoint of improving productivity, the pressure application time is preferably 5 seconds or less, 3 seconds or less, or 2 seconds or less.

[0051] (glue) An adhesive (semiconductor adhesive) that can be used in the above-mentioned method for manufacturing a semiconductor device will be described below.

[0052] The adhesive according to one embodiment contains a thermosetting resin and a curing agent thereof. The adhesive may further contain a polymer component having a weight average molecular weight of 10,000 or more.

[0053] <Thermosetting resin> The thermosetting resin preferably has a weight average molecular weight of less than 10,000. When a thermosetting resin having a weight average molecular weight of less than 10,000 reacts with a curing agent, the curing property of the adhesive is improved. This is also preferable from the viewpoint of suppressing voids and heat resistance.

[0054] Examples of the thermosetting resin include epoxy resin and acrylic resin.

[0055] The epoxy resin is not particularly limited as long as it has two or more epoxy groups in the molecule. As the epoxy resin, bisphenol A type, bisphenol F type, naphthalene type, phenol novolac type, cresol novolac type, phenol aralkyl type, biphenyl type, triphenylmethane type, dicyclopentadiene type, various polyfunctional epoxy resins, etc. can be used. These can be used alone or as a mixture of two or more types.

[0056] The acrylic resin is not particularly limited as long as it has one or more (meth)acrylic groups in the molecule. For example, bisphenol A type, bisphenol F type, naphthalene type, phenol novolac type, cresol novolac type, phenol aralkyl type, biphenyl type, triphenylmethane type, dicyclopentadiene type, fluorene type, adamantane type, various polyfunctional acrylic resins, etc. can be used as the acrylic resin. These can be used alone or as a mixture of two or more kinds. In this specification, the term "(meth)acrylic group" is used as a term meaning either an acrylic group or a methacrylic group.

[0057] The acrylic resin is preferably solid at room temperature (25° C.). A solid acrylic resin is less likely to generate voids than a liquid acrylic resin, and the adhesive in the B-stage before curing has less tack, making it easier to handle.

[0058] The number of (meth)acrylic groups in the acrylic resin per molecule is preferably 3 or less. If the number of (meth)acrylic groups is 4 or more, the number of functional groups is large, so curing does not proceed sufficiently in a short period of time, and the curing reaction rate decreases (the curing network may proceed too quickly, leaving unreacted groups).

[0059] The content of the thermosetting resin in the adhesive is, for example, 10 to 50 parts by mass relative to 100 parts by mass of the total mass of the adhesive. If the content of the thermosetting resin is 10 parts by mass or less, it tends to be difficult to sufficiently control the flow of the resin after curing. If the content of the thermosetting resin is 50 parts by mass or more, the cured product tends to be too hard, which causes the semiconductor device to warp significantly.

[0060] <Hardening agent> Examples of the curing agent include phenolic resin curing agents, acid anhydride curing agents, amine curing agents, imidazole curing agents, phosphine curing agents, azo compounds, and organic peroxides. Among these, imidazole curing agents are preferred.

[0061] The phenol resin-based curing agent is not particularly limited as long as it has two or more phenolic hydroxyl groups in the molecule, and for example, phenol novolac, cresol novolac, phenol aralkyl resin, cresol naphthol formaldehyde polycondensate, triphenylmethane type polyfunctional phenol, and various polyfunctional phenol resins can be used. These can be used alone or in a mixture of two or more kinds.

[0062] The equivalent ratio of the phenolic resin-based curing agent to the thermosetting resin (phenolic hydroxyl group / epoxy group, molar ratio) is preferably 0.3 to 1.5, more preferably 0.4 to 1.0, and even more preferably 0.5 to 1.0, from the viewpoint of good curability, adhesion, and storage stability. When the equivalent ratio is 0.3 or more, the curability and adhesion tend to improve, and when it is 1.5 or less, there is no excess of unreacted phenolic hydroxyl groups remaining, the water absorption rate is kept low, and insulation reliability tends to improve.

[0063] Examples of the acid anhydride curing agent that can be used include methylcyclohexanetetracarboxylic dianhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic dianhydride, and ethylene glycol bisanhydrotrimellitate. These can be used alone or in combination of two or more.

[0064] The equivalent ratio of the acid anhydride curing agent to the thermosetting resin (acid anhydride group / epoxy group, molar ratio) is preferably 0.3 to 1.5, more preferably 0.4 to 1.0, and even more preferably 0.5 to 1.0, from the viewpoint of good curability, adhesion, and storage stability. When the equivalent ratio is 0.3 or more, the curability and adhesion tend to improve, and when it is 1.5 or less, there is no excess of unreacted acid anhydride remaining, the water absorption rate is kept low, and insulation reliability tends to improve.

[0065] As the amine-based curing agent, for example, dicyandiamide can be used.

[0066] The equivalent ratio of the amine-based curing agent to the thermosetting resin (amine / epoxy group, molar ratio) is preferably 0.3 to 1.5, more preferably 0.4 to 1.0, and even more preferably 0.5 to 1.0, from the viewpoint of good curability, adhesion, and storage stability. When the equivalent ratio is 0.3 or more, the curability and adhesion tend to be improved, and when it is 1.5 or less, there is no excess of unreacted amine remaining, and insulation reliability tends to be improved.

[0067] Examples of the imidazole-based curing agent 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'-methylimidazolyl-(1')]-ethyl-s-triazine, and 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine. -[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. Among these, from the viewpoints of excellent curing properties, storage stability and connection reliability, 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 are preferred. These may be used alone or in combination of two or more kinds. They may also be microencapsulated to form latent curing agents.

[0068] The content of the imidazole-based curing agent is preferably 0.1 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, relative to 100 parts by mass of the thermosetting resin. When the content of the imidazole-based curing agent is 0.1 part by mass or more, the curability tends to improve, and when it is 20 parts by mass or less, the adhesive does not cure before the metal bond is formed, and connection failure tends to be less likely to occur.

[0069] Examples of phosphine-based curing agents include triphenylphosphine, tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium tetra(4-methylphenyl)borate, and tetraphenylphosphonium(4-fluorophenyl)borate.

[0070] The content of the phosphine-based curing agent is preferably 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, relative to 100 parts by mass of the thermosetting resin. When the content of the phosphine-based curing agent is 0.1 part by mass or more, the curability tends to be improved, and when it is 10 parts by mass or less, the adhesive does not cure before the metal bond is formed, and connection failure tends to be less likely to occur.

[0071] The phenolic resin-based curing agent, the acid anhydride-based curing agent, and the amine-based curing agent can each be used alone or in combination of two or more. The imidazole-based curing agent and the phosphine-based curing agent can each be used alone, or can be used together with the phenolic resin-based curing agent, the acid anhydride-based curing agent, or the amine-based curing agent.

[0072] Examples of organic peroxides include ketone peroxides, peroxyketals, hydroperoxides, dialkyl peroxides, diacyl peroxides, peroxydicarbonates, and peroxyesters. From the viewpoint of storage stability, hydroperoxides, dialkyl peroxides, and peroxyesters are preferred. Furthermore, from the viewpoint of heat resistance, hydroperoxides and dialkyl peroxides are preferred. These can be used alone or as a mixture of two or more kinds.

[0073] The content of the organic peroxide is preferably 0.5 to 10% by mass, more preferably 1 to 5% by mass, based on the acrylic resin. If the content of the organic peroxide is less than 0.5% by mass, curing tends not to proceed sufficiently. If the content of the organic peroxide is more than 10% by mass, curing proceeds rapidly and the number of reaction points increases, resulting in a shortened molecular chain or remaining unreacted groups, which tends to reduce reliability.

[0074] The curing agent to be combined with the epoxy resin or acrylic resin is not particularly limited as long as the curing proceeds. From the viewpoints of handling, storage stability, and curing, the curing agent to be combined with the epoxy resin is preferably a combination of a phenol resin curing agent and an imidazole curing agent, a combination of an acid anhydride curing agent and an imidazole curing agent, a combination of an amine curing agent and an imidazole curing agent, or an imidazole curing agent alone. Since productivity is improved when connecting in a short time, it is more preferable to use an imidazole curing agent with excellent fast curing properties alone. Since volatile components such as low molecular weight components can be suppressed when curing in a short time, it is also possible to suppress the generation of voids. In addition, the curing agent to be combined with the acrylic resin is preferably an organic peroxide from the viewpoints of handling and storage stability.

[0075] <Polymer components with a weight-average molecular weight of 10,000 or more> Examples of the polymer component having a weight average molecular weight of 10,000 or more include epoxy resin, 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, acrylic rubber, etc., among which epoxy resin, phenoxy resin, polyimide resin, acrylic resin, acrylic rubber, cyanate ester resin, polycarbodiimide resin, etc., which are excellent in heat resistance and film formability, are preferred, and epoxy resin, phenoxy resin, polyimide resin, acrylic resin, acrylic rubber, which are excellent in heat resistance and film formability, are more preferred. These polymer components can be used alone or as a mixture or copolymer of two or more kinds. The polymer component having a weight average molecular weight of 10,000 or more may be a thermosetting resin that reacts with a curing agent.

[0076] The mass ratio of the polymer component to the above-mentioned epoxy resin is not particularly limited. In order for the adhesive to maintain a film-like form, the mass ratio of the epoxy resin to the polymer component is preferably 0.01 to 5, 0.05 to 4, or 0.1 to 3. If this mass ratio is less than 0.01, the curing property may decrease, and the adhesive strength may decrease. If this mass ratio is more than 5, the film formability may decrease.

[0077] The mass ratio of the polymer component to the acrylic resin is not particularly limited. The mass ratio of the acrylic resin to the polymer component is preferably 0.01 to 10, more preferably 0.05 to 5, and even more preferably 0.1 to 5. If this mass ratio is less than 0.01, the curability may decrease, and the adhesive strength may decrease. If this mass ratio is more than 10, the film formability may decrease.

[0078] The glass transition temperature (Tg) of the polymer component is preferably 120°C or less, more preferably 100°C or less, and even more preferably 85°C or less, from the viewpoint of excellent adhesion of the adhesive to the substrate or semiconductor chip. If the Tg of the polymer component exceeds 120°C, it becomes difficult to fill the bumps of the semiconductor chip, the electrodes formed on the substrate, the wiring pattern, and other irregularities with the adhesive, so that the effect of suppressing voids may become relatively small. The Tg here is the Tg measured using a DSC (PerkinElmer Co., Ltd., DSC-7 type) under conditions of a sample amount of 10 mg, a heating rate of 10°C / min, and an air atmosphere.

[0079] The weight average molecular weight of the polymer component is 10000 or more. In order to exhibit good film formability by itself, the weight average molecular weight of the polymer component is preferably 30000 or more, more preferably 40000 or more, and even more preferably 50000 or more. In this specification, the weight average molecular weight means a value measured by gel permeation chromatography (GPC) and calculated in terms of standard polystyrene.

[0080] The adhesive may contain a flux component, i.e., a flux activator, which is a compound that exhibits flux activity (activity to remove oxides and impurities). Examples of flux activators include nitrogen-containing compounds having unshared electron pairs, such as imidazoles and amines, carboxylic acids, phenols, and alcohols. Compared to alcohols, organic acids exhibit stronger flux activity and improve connectivity.

[0081] In order to control the viscosity and physical properties of the cured product, and to suppress the generation of voids and moisture absorption rate when semiconductor chips are connected to each other or when a semiconductor chip is connected to a substrate, a filler may be blended into the adhesive. Examples of insulating inorganic fillers include glass, silica, alumina, titanium oxide, carbon black, mica, boron nitride, and the like. Among these, silica, alumina, titanium oxide, and boron nitride are preferred, and silica, alumina, and boron nitride are more preferred. Examples of whiskers include aluminum borate, aluminum titanate, zinc oxide, calcium silicate, magnesium sulfate, and boron nitride. Examples of resin fillers that can be used include polyurethane, polyimide, methyl methacrylate resin, and methyl methacrylate-butadiene-styrene copolymer resin (MBS). These fillers and whiskers can be used alone or as a mixture of two or more types. There are no particular limitations on the shape, particle size, and blending amount of the filler.

[0082] Compared to inorganic fillers, resin fillers are more suitable for improving reflow resistance because they can impart flexibility at high temperatures such as 260°C. In addition, because they impart flexibility, they are also effective in improving film formability.

[0083] From the viewpoint of insulation reliability, the filler is preferably insulating. A semiconductor adhesive that does not contain a conductive metal filler such as a silver filler or a solder filler is preferable.

[0084] From the viewpoint of improving dispersibility and adhesive strength, surface-treated fillers are preferred. Examples of surface treatments include glycidyl-based (epoxy-based), amine-based, phenyl-based, phenylamino-based, (meth)acrylic, and vinyl-based. From the viewpoint of dispersibility, fluidity, and adhesive strength, glycidyl-based, phenylamino-based, and (meth)acrylic-based are preferred. From the viewpoint of storage stability, phenyl-based, acrylic, and (meth)acrylic are more preferred. From the viewpoint of ease of surface treatment, silane treatments (epoxy silane-based, amino silane-based, acrylic silane-based, etc.) are preferred.

[0085] These fillers and whiskers can be used alone or as a mixture of two or more kinds. There are no particular limitations on the shape, particle size, and amount of the filler. In addition, the physical properties may be appropriately adjusted by surface treatment.

[0086] The average particle size of the filler is preferably 1.5 μm or less from the viewpoint of preventing jamming during flip chip connection, and more preferably 1.0 μm or less from the viewpoints of visibility and transparency.

[0087] The content of the filler is preferably 30 to 90% by mass, more preferably 40 to 80% by mass, based on the solid content mass of the adhesive (mass of components other than the solvent). If the content of the filler is less than 30% by mass, the heat dissipation is low, and voids tend to occur and the moisture absorption rate tends to increase. If the content of the filler is more than 90% by mass, the viscosity of the adhesive increases, the flowability decreases, the filler becomes trapped in the connection, and the connection reliability tends to decrease.

[0088] The adhesive may contain an ion trapper, an antioxidant, a silane coupling agent, a titanium coupling agent, and a leveling agent. These may be used alone or in combination of two or more. The amount of each additive may be appropriately adjusted so that the effect of each additive is exerted.

[0089] The adhesive is preferably in a film form. A film form improves productivity. A method for producing a film-like adhesive (film form) is described below.

[0090] A thermosetting resin, a curing agent, a polymer component, a filler, and other additives are added to an organic solvent, and dissolved or dispersed by stirring, mixing, kneading, etc. to prepare a resin varnish. The resin varnish is applied to a substrate film that has been subjected to a release treatment using a knife coater, roll coater, applicator, die coater, or comma coater, and then the organic solvent is reduced by heating to form a film-like adhesive on the substrate film. Alternatively, the resin varnish may be spin-coated on a wafer or the like to form a film before the organic solvent is reduced by heating, and then the film-like adhesive may be formed on the wafer by a method in which the resin varnish is spin-coated on a wafer or the like to form a film, and then the solvent is dried.

[0091] The substrate film is not particularly limited as long as it has heat resistance sufficient to withstand the heating conditions when volatilizing the organic solvent, and examples thereof include polyester film, polypropylene film, polyethylene terephthalate film, polyimide film, polyetherimide film, polyether naphthalate film, methylpentene film, etc. The substrate film is not limited to a single layer made of these films, and may be a multilayer film made of two or more materials.

[0092] Specifically, the conditions for volatilizing the organic solvent from the applied resin varnish are preferably heating at 50 to 200° C. for 0.1 to 90 minutes. If there is no effect on voids or viscosity adjustment after mounting, the conditions are preferably such that the organic solvent volatilizes to 1.5% or less. EXAMPLES

[0093] The present invention will be described in more detail below with reference to examples, although the present invention is not limited to these examples.

[0094] (1) Film adhesive A film-like adhesive having the composition shown in Table 1 was prepared.

[0095] [Table 1]

[0096] Details of each raw material in the table are as follows: (i) Thermosetting resin (weight average molecular weight (Mw) less than 10,000) Epoxy Resin EP1032H60: Triphenolmethane skeleton-containing multifunctional solid epoxy resin (manufactured by Mitsubishi Chemical Corporation, weight average molecular weight: 800-2000) YL983U: Bisphenol F type liquid epoxy resin (manufactured by Mitsubishi Chemical Corporation, molecular weight: approximately 336) YL7175-1000: Flexible semi-solid epoxy resin (manufactured by Mitsubishi Chemical Corporation, weight average molecular weight: 1000-5000) (ii) Hardener 2MAOK-PW: 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct (manufactured by Shikoku Kasei Co., Ltd.) (iii) A polymer component having a weight average molecular weight (Mw) of 10,000 or more ZX1356-2: Phenoxy resin (Tohto Kasei Co., Ltd., glass transition temperature: approx. 71°C, weight average molecular weight: approx. 63,000) (iv) Fluxing agent (carboxylic acid) 2-Methylglutaric acid (Aldrich, melting point: approx. 77°C) (v) Fila Inorganic Filler SE2050: Silica filler (manufactured by Admatechs Co., Ltd., average particle size 0.5 μm) YA050C-SP: Phenyl surface-treated nano-silica filler (Admatechs Co., Ltd., average particle size: approx. 50 nm) Resin filler EXL-2655: Organic filler (manufactured by Rohm and Haas Japan, core-shell type organic fine particles) (vi)Additives FCA107: Solid silanol (manufactured by Dow Corning Toray Co., Ltd., weight average molecular weight: approximately 3000)

[0097] (2) Fabrication of semiconductor devices (Temporary crimping process) The film-like adhesive prepared above was cut into a size of 8 mm square and 0.045 mm thick, and this was attached onto a semiconductor chip (10 mm, thickness 0.1 mm, connection metal: Au, product name: WALTS-TEG IP80, manufactured by Waltz Corporation). A semiconductor chip with solder bumps (chip size: 7.3 mm x 7.3 mm, thickness 0.05 mm, bump (connection) height: about 45 μm (total of copper pillar and solder), number of bumps: 1048 pins, pitch 80 μm, product name: WALTS-TEG CC80, manufactured by Waltz Corporation) was temporarily bonded thereto by heating and pressing with a flip chip bonder (FCB3, manufactured by Panasonic Corporation). The conditions for temporary bonding were 130°C, 75 N, and 2 seconds.

[0098] (Main crimping process) The pre-bonded laminate (pre-bonded body) was heated and pressed under the following conditions to bond the connecting portions of the semiconductor chips together, thereby producing a sample for connection evaluation. Example 1 Equipment: Pressure reflow equipment (VSU28, manufactured by Synapex Co., Ltd.) Heating temperature / time: 170℃ / 5 minutes, then 260℃ / 5 minutes Pressure: 0.4MPa (atmospheric pressure) Example 2 Equipment: Pressure reflow equipment (VSU28, manufactured by Synapex Co., Ltd.) ·Heating temperature / time: 260 degrees / 5 minutes Pressure: 0.4MPa (atmospheric pressure) Comparative Example 1 Equipment: Oven (DKN402, manufactured by Yamato Scientific Co., Ltd.) Heating temperature / time: 170 degrees / 5 minutes, then 260 degrees / 5 minutes Pressure: Atmospheric pressure Comparative Example 2 Equipment: Oven (DKN402, manufactured by Yamato Scientific Co., Ltd.) ·Heating temperature / time: 260 degrees / 5 minutes Pressure: Atmospheric pressure

[0099] (2) Connection evaluation After bonding, the above samples were measured for initial continuity using a multimeter (R6871E, manufactured by ADC Corporation). Samples with an initial connection resistance of the inner circumference of the peripheral part of 45 Ω or less and an initial connection resistance of the outer circumference of 85 Ω or less were rated as "A", and samples with a higher resistance or no connection were rated as "B".

[0100] (3) Void evaluation The appearance image of the above sample after the main bonding was taken by an ultrasonic imaging diagnostic device (Insight-300, manufactured by Insight Co., Ltd.). From the obtained image, an image of the adhesive layer between the chips was captured by a scanner (GT-9300UF, manufactured by Seiko Epson Corporation). In the captured image, voids were identified by color correction and two-tone gradation using image processing software (Adobe Photoshop (trade name)), and the proportion of the voids was calculated using a histogram. The area of ​​the entire adhesive layer including the voids was taken as 100%. The area ratio of the voids was 5% or less and "A", and the area ratio of the voids was more than 55% and "B". The evaluation results are shown in Table 2.

[0101] [Table 2]

[0102] It was confirmed that the manufacturing method of the present invention, which involves the application of air pressure during main pressure bonding, makes it possible to simultaneously suppress voids and ensure connection. [Explanation of symbols]

[0103] Reference Signs List 1...semiconductor chip, 2...substrate, 10...semiconductor chip body, 15, 16...wiring, 20...substrate body, 30, 32, 33...bumps, 34...through electrodes, 40...adhesive layer, 50...interposer body, 100, 200, 300, 400, 500...semiconductor device.

Claims

1. A step of temporarily bonding a first member having a connection portion and a second member having a connection portion via an adhesive at a temperature lower than the melting point of the connection portion of the first member and the melting point of the connection portion of the second member (excluding the step of bonding the first member and the second member via the adhesive either in a reduced pressure atmosphere or in an atmosphere pressurized by a device capable of pressurizing by atmospheric pressure) to obtain a temporarily bonded body in which the connection portion of the first member and the connection portion of the second member are arranged opposite to each other; a step of heating the temporary pressure-bonded body to a temperature equal to or higher than the melting point of at least one of the connection portion of the first member or the connection portion of the second member while pressurizing the temporary pressure-bonded body only by air pressure, thereby joining the connection portions arranged opposite to each other so as to be electrically connected to each other; Equipped with The first member is a semiconductor chip or a semiconductor wafer, and the second member is a wiring circuit board, a semiconductor chip, or a semiconductor wafer. A method for manufacturing a semiconductor device.

2. 2. The method for manufacturing a semiconductor device according to claim 1, wherein the pressure is higher than atmospheric pressure and is equal to or lower than 0.5 MPa.

3. 2. The method for manufacturing a semiconductor device according to claim 1, wherein the adhesive contains a thermosetting resin having a weight average molecular weight of less than 10,000 and a curing agent thereof.

4. 4. The method for manufacturing a semiconductor device according to claim 3, wherein the adhesive further contains a polymer component having a weight average molecular weight of 10,000 or more.

5. 5. The method for manufacturing a semiconductor device according to claim 4, wherein the polymer component has a weight average molecular weight of 30,000 or more and a glass transition temperature of 100[deg.] C. or less.

6. The method for manufacturing a semiconductor device according to any one of claims 1 to 5, wherein the adhesive is a film-like adhesive.

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