JP2019220619A - Method of manufacturing semiconductor device, and adhesive for semiconductor used therefor - Google Patents

Abstract

To suppress a void of a semiconductor device and to easily secure excellent connection reliability while employing a method comprising obtaining a temporary contact-bonded body by heating and pressing a member such as a semiconductor chip at a temperature lower than the fusion point of a connection part thereof when manufacturing the semiconductor device in an FC connection manner.SOLUTION: There is disclosed a method of manufacturing a semiconductor device that comprises the processes of: obtaining a temporary contact-bonded body having a connection part of a first member and a connection part of a second member arranged opposite each other; and pressing the temporary contact-bonded body while heating it so as to obtain a contact-bonded body having the connection part of the first member and the connection part of the second member joined together. The first member and second member are semiconductor chips, etc. An adhesive contains epoxy resin, a hardener, and a flux agent, and has a minimum fusion viscosity of 1,500-3,500 Pa s or less and a gel time of 10-30 seconds or less at 200°C.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing a semiconductor device, and a semiconductor adhesive used for the method.

  Conventionally, when connecting a semiconductor chip and a substrate, a wire bonding method using a thin metal wire such as a gold wire has been widely applied.

  In recent years, in order to respond to demands for high performance, high integration, high speed, and the like for semiconductor devices, conductive protrusions called bumps are provided as connection portions on a semiconductor chip or a wiring circuit board, and wiring between the semiconductor chip and the semiconductor chip is established by connecting the connection portions. A flip chip connection method (FC connection method) for directly connecting a circuit board or another semiconductor chip is widely used. For example, a COB (Chip On Board) type connection method that is a connection between a semiconductor chip and a printed circuit board is an FC connection method. The FC connection method is widely used in a CoC (Chip On Chip) type connection method in which bumps or wirings are provided as connection portions on a semiconductor chip and the semiconductor chips are connected to each other.

  In an area array type semiconductor package used for a CPU, an MPU, or the like, high functionality is strongly required. Therefore, there is a tendency to increase the size of the chip, increase the number of pins (bumps, wirings), and increase the pitch and gap.

  In the FC connection method, generally, from the viewpoint of the reliability of the connection portion, the connection portion such as solder, tin, gold, silver, or copper is often metal-joined.

  In packages that require further miniaturization, thinning, and high functionality, chip stack type packages in which the above-described connection methods are multi-staged, POP (Package On Package), TSV (Through-Silicon Via), and the like are also widely used. Have begun to do. These techniques are frequently used because the package can be reduced by arranging the semiconductor chips three-dimensionally instead of planarly. They are also effective in improving the performance of semiconductors, reducing noise, reducing the mounting area, and saving power, and are attracting attention as next-generation semiconductor wiring technologies.

  From the viewpoint of productivity improvement, COW (Chip On Wafer) for connecting a semiconductor chip on a wafer and then singulating to produce a semiconductor package, and WOW (Chip On Wafer for forming a semiconductor package by crushing wafers and thereafter singulating the semiconductor package). Wafer On Wafer) is also attracting attention.

  In addition, a gang bonding method, which aligns chips on a wafer or a map substrate and temporarily press-bonds them, and press-bonds a plurality of chips collectively to secure a connection, has attracted attention from the viewpoint of improving productivity.

JP 2008-294382 A

  In assembling a semiconductor device of the FC connection method, generally, first, a semiconductor chip is picked up from a diced semiconductor wafer by a collet and supplied to a pressing device. Next, the semiconductor chip is pressure-bonded to the printed circuit board or another semiconductor chip by a pressing device. During crimping, the temperature of the pressing device is increased so that the metal of one or both of these connections reaches the melting point or higher so that a metal bond is formed. Then, after the high-temperature pressing device is cooled, the semiconductor chip is supplied to the pressing device again. A semiconductor adhesive may be supplied in advance on the semiconductor chip picked up by the collet, and in this case, in order to continuously manufacture the semiconductor device, the pressing device is operated at a high temperature at which the metal of the connection portion is melted. It is necessary to cool the semiconductor chip to which the adhesive has been supplied to a low temperature at which it can be supplied.

  In the FC connection method in which the connection is secured by heating at or above the melting point of the metal of the connection portion, the pressure tool immediately after pressure bonding is at a high temperature (for solder, for example, 240 ° C. or higher). If the semiconductor chip is picked up from the collet without cooling the high-temperature crimping tool, the heat of the pressing device is transferred to the collet, and the temperature of the collet itself rises, causing a problem and reducing productivity. In a semiconductor chip to which the semiconductor adhesive is supplied, when the heat of the pressing device is transferred to the collet and the temperature of the semiconductor adhesive rises and the viscosity develops, the semiconductor adhesive adheres to the collet and productivity is reduced. descend. Even when only a semiconductor chip is used, if the temperature of the collet rises, when picking up individual semiconductor chips from the dicing tape, heat is transmitted to the dicing tape via the collet, which lowers the pick-up performance and reduces productivity. descend.

  As described above, the FC connection method is performed in two steps of a step of temporarily pressing at a temperature lower than the melting point of the metal of the connection portion and a step of heating the obtained temporarily pressed body at a temperature of at least the melting point of the metal at the connection portion. Can be avoided. However, in the case of this method, it has been clarified that the voids generated in the step of the temporary pressure bonding are difficult to be removed, and that sufficient connection reliability may not be easily ensured.

  Therefore, an object of one aspect of the present invention is to provide a temporary bonded body by heating and pressing a member such as a semiconductor chip at a temperature lower than the melting point of the connection portion when a semiconductor device is manufactured by the FC connection method. Another object of the present invention is to suppress voids in a semiconductor device and easily secure good connection reliability while employing a method including the above.

  One aspect of the present invention is to provide a first member having a connection portion and a second member having a connection portion, using an adhesive, the melting point of the connection portion of the first member and the connection portion of the second member. Temporarily pressing at a temperature lower than the melting point of the step of obtaining a temporary pressure-bonded body in which the connecting portion of the first member and the connecting portion of the second member are arranged to face each other, Pressure is applied while heating to a temperature equal to or higher than at least one of the melting points of the connection part of one member or the connection part of the second member, so that the connection part of the first member and the connection part of the second member are joined. A method of manufacturing a semiconductor device, comprising: 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. The adhesive contains an epoxy resin, a curing agent and a fluxing agent, has a minimum melt viscosity of 1500 Pa · s or more and 3500 Pa · s or less, and shows a gel time of 10 seconds or more and 30 seconds or less at 200 ° C.

  Another aspect of the present invention relates to a semiconductor adhesive for use as an adhesive in the above method. This adhesive for semiconductors contains an epoxy resin, a curing agent and a fluxing agent, has a minimum melt viscosity of 1500 Pa · s or more and 3500 Pa · s or less, and shows a gel time of 10 seconds or more and 30 seconds or less at 200 ° C.

  According to one aspect of the present invention, in the case of manufacturing a semiconductor device by the FC connection method, the method includes heating and pressing a member such as a semiconductor chip at a temperature lower than the melting point of the connection portion to obtain a temporary crimped body. While adopting the method, voids in the semiconductor device can be suppressed, and good connection reliability can be easily ensured. The method of the present invention is also excellent in that a large number of highly reliable semiconductor devices can be manufactured in a short time.

It is a flowchart showing one embodiment of a process of obtaining a temporary press-fit body by press-fitting a first member and a second member. It is a process figure showing one embodiment of the process of heating and pressurizing a temporary pressure bonding object and obtaining a pressure bonding object. It is a flowchart showing one embodiment of the process of heating a pressure bonding object under pressurized atmosphere. FIG. 4 is a schematic sectional view showing another embodiment of the semiconductor device. FIG. 4 is a schematic sectional view showing another embodiment of the semiconductor device. FIG. 4 is a schematic sectional view showing another embodiment of the semiconductor device. FIG. 4 is a schematic sectional view showing another embodiment of the semiconductor device.

  Hereinafter, some embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

(Method of Manufacturing Semiconductor Device)
(First Embodiment of Method for Manufacturing Semiconductor Device)
1 and 2 are process diagrams showing a first embodiment of a method for manufacturing a semiconductor device. As shown in FIG. 1, the method according to the first embodiment includes a semiconductor chip 1 (first member) having bumps 30 (connections) and a printed circuit board 2 (second connection) having wirings 16 (connections). Is temporarily bonded at a temperature lower than the melting point of the bump 30 and the melting point of the wiring 16 via the adhesive layer 40, so that the temporary bonded body 4 in which the bump 30 and the wiring 16 are arranged to face each other. And pressing the pre-pressed body 4 while heating it to a temperature equal to or higher than the melting point of at least one of the bumps 30 and the wirings 16 as shown in FIG. Obtaining a compressed body 6 that has been made. In the press-bonded body 6, the semiconductor chip 1 (first member) and the printed circuit board 2 (second member) are usually electrically connected to each other by metal-joining their connection portions, and are cured. It is adhered via an adhesive layer 40. By using an adhesive described later as the adhesive forming the adhesive layer 40, voids in the obtained semiconductor device can be suppressed, and good connection reliability can be easily secured.

  As shown in FIG. 1A, a semiconductor chip 1 having a semiconductor chip main body 10 and a bump 30 as a connecting part is connected to a substrate main body 20 and a wiring circuit board 2 having a wiring 16 as a connecting part. The laminated body 3 is formed by superimposing the adhesive layers 40 while arranging them between them. After being formed by dicing the semiconductor wafer, the semiconductor chip 1 is picked up and transported onto the printed circuit board 2, and is aligned so that the bump 30 as a connection portion and the wiring 16 are opposed to each other. The laminated body 3 is formed on a stage 42 of a pressing device 43 having a pair of a pressure bonding head 41 and a stage 42 as a pair of temporary pressure bonding pressing members arranged to face each other. The bump 30 is provided on the wiring 15 provided on the semiconductor chip body 10. The wiring 16 of the printed circuit board 2 is provided at a predetermined position on the board body 20. Each of the bump 30 and the wiring 16 has a surface formed of a metal material.

  The adhesive layer 40 may be a layer formed by attaching a film-shaped adhesive prepared in advance to the printed circuit board 2. The adhesive in the form of a film can be attached by hot pressing, roll lamination, vacuum lamination, or the like. The supply area and the thickness of the adhesive layer are appropriately set according to the size of the semiconductor chip 1 or the wiring circuit board 2, the height of the connection portion, and the like. A film adhesive may be attached to the semiconductor chip 1. The semiconductor chip 1 to which the film-like adhesive is adhered may be manufactured by attaching the film-like adhesive to the semiconductor wafer and then dicing the semiconductor wafer into individual semiconductor wafers.

  Subsequently, as shown in FIG. 1B, the laminate 3 is heated and pressurized by being sandwiched between a stage 42 as a pressing member for provisional pressure bonding and a pressure bonding head 41, whereby the semiconductor chip 1 is pressed. The printed circuit board 2 is temporarily pressure-bonded to obtain a temporary pressure-bonded body 4. In the case of the embodiment shown in FIG. 1, the pressure bonding head 41 is arranged on the semiconductor chip 1 side, and the stage 42 is arranged on the printed circuit board 2 side. A flip chip bonder or the like can be used as a temporary pressure bonding pressing device having a stage and a pressure bonding head.

  When at least one of the stage 42 and the pressure bonding head 41 heats and pressurizes the multilayer body 3 for temporary pressure bonding, the melting point of the bump 30 as a connection part of the semiconductor chip 1 and the connection point of the wiring circuit board 2 The wiring 16 is heated to a temperature lower than the melting point. In the present specification, the “melting point of the connection portion” means the melting point of the metal material forming the surface of the connection portion.

  In the step of obtaining the temporary pressure-bonding body 4, the temperature of the temporary pressure-bonding pressing member is set low so that heat is not transferred to the semiconductor chip or the like when the semiconductor chip or the like as the first member is picked up. During the heating and pressurizing of the laminate 3 for temporary compression, the pressing member for temporary compression may be heated to a certain high temperature in order to increase the fluidity of the adhesive layer 40 to such an extent that entrained voids can be eliminated. . In order to shorten the cooling time, the difference between the temperature of the pressing member when picking up the semiconductor chip or the like and the temperature of the pressing member when heating and pressing the laminate 3 to obtain the temporary press-bonded body 4 is small. Good. This temperature difference is preferably 100 ° C. or less, more preferably 60 ° C. or less, and even more preferably substantially 0 ° C. This temperature difference may be constant. When the temperature difference is 100 ° C. or less, the time required for cooling the pressing member for provisional pressure bonding can be shortened.

  The temperature of the temporary pressure-bonding pressing member when heating and pressing the laminate 3 to obtain the temporary pressure-bonded body 4 may be lower than the reaction start temperature of the adhesive layer 40. The reaction start temperature is obtained by using a DSC (manufactured by Perkin Elmer, DSC-Pyrs1), when measuring under the conditions of an adhesive sample amount of 10 mg, a heating rate of 10 ° C./min, and a measurement atmosphere of air or nitrogen. On-set temperature in the obtained DSC thermogram.

  The pressing load for pressing the laminated body 3 to obtain the temporary pressure-bonded body 4 is appropriately set in consideration of the number of bumps, absorption of bump height variations, and control of the amount of bump deformation. In the temporary press-bonded body 4, the connection portion (the bump 30) of the semiconductor chip 1 may be in contact with the connection portion (the wiring 16) of the printed circuit board 2. As a result, a metal bond is likely to be formed in a subsequent step, and the bite of the adhesive tends to be small. From the viewpoint of bringing the connection portions into sufficient contact with each other, the pressing load for pressing the stacked body 3 to obtain the temporary crimped body 4 is, for example, 0.009 to 0.1 per bump 30 of the semiconductor chip 1. It may be 2N.

  The time during which the laminate 3 is pressed to obtain the temporary pressure-bonded body 4 may be 5 seconds or less, 3 seconds or less, or 2 seconds or less, and 0.1 seconds or more from the viewpoint of improving productivity. Is also good.

  After the provisional pressure-bonded body 4 is obtained, as shown in FIGS. 2A and 2B, a pressing device 46 having a stage 45 and a pressure-bonding head 44, which are provided separately from the pressing device 43 and are opposed to each other. The pre-pressed body 4 is pressurized while being heated by a hot press sandwiched between the stage 45 and the press-bonding head 44 to form the press-bonded body 6. At least one of the stage 45 and the pressure bonding head 44 is heated to a temperature equal to or higher than at least one of the melting point of the bump 30 and the melting point of the wiring 16 when the temporary pressure bonding body 4 is heated and pressed. In the embodiment of FIG. 2, the pressure bonding head 44 is arranged on the semiconductor chip 1 side of the temporary pressure bonding body 4, and the stage 45 is arranged on the wiring circuit board 2 side of the temporary pressure bonding body 4. In the press-bonded body 6, the wiring 16 and the bump 30 are sealed by an adhesive layer 40 so as to be shielded from an external environment. The press-bonded body 6 may be used as a semiconductor device, or the adhesive layer 40 may be further cured by further heating the press-bonded body 6 under a pressurized atmosphere as in a third embodiment described later.

  When the temporary pressure-bonded body 4 is heated and pressed, the oxide film on the surface of the connection portion may be removed. For that purpose, the temperature of the stage 45 and / or the pressure bonding head 44 may be set to a temperature higher than the temperature at which the oxide film on the surface of the connection portion is efficiently removed. From such a viewpoint, the temperature of the stage 45 and / or the pressure bonding head 44 may be 220 ° C. or more and 330 ° C. or less. When the metal material of the connection portion contains solder, if the temperature of the stage 45 and / or the pressure bonding head 44 is 220 ° C. or higher, the solder of the connection portion is melted, and a sufficient metal bond is easily formed. When the temperature is 330 ° C. or lower, voids are hardly generated, and solder is hardly scattered. The temperature of the stage 45 and / or the pressure bonding head 44 may be 220 ° C. or higher when the metal material of the connection portion includes Sn / Ag having a melting point of about 220 ° C.

  When applying pressure while heating the temporary press-bonded body using a pressing device, the pressing load should take into account the removal of the oxide film on the connection part surface, the number of bumps, absorption of bump height variations, and control of the amount of bump deformation. Is set as appropriate. When the pressing load is large, the oxide film tends to be easily removed. The pressing load may be, for example, 0.009 to 0.2 N per connection portion (bump) of the semiconductor chip. When the pressing load is 0.009 N or more, the oxide film formed on the connection portion is easily removed, and the adhesive is hardly trapped in the connection portion. Further, when the pressing load is 0.2 N or less, problems such as crushing or scattering of the bumps including the solder and the like hardly occur.

  The time for pressurizing the temporary pressure-bonded body 4 while heating it to obtain the pressure-bonded body 6 may be 5 seconds or less, 3 seconds or less, or 2 seconds or less, and 0.1 seconds or more from the viewpoint of improving productivity. It may be.

  The method of heating and pressurizing the temporary press-bonded body 4 is not limited to the hot press as shown in FIG. 2. For example, the temporary press-bonded body 4 may be heated using a heating furnace under a pressurized atmosphere in the heating furnace. . As the heating furnace, a reflow furnace, a pressure oven, or the like can be used. The atmosphere in the heating furnace is not particularly limited, but may be air, nitrogen, formic acid, or the like.

(Second Embodiment of Method for Manufacturing Semiconductor Device)
In the method according to the second embodiment, after obtaining the press-bonded body 6 by the steps illustrated in FIGS. 1 and 2 and the like, as shown in FIG. And the step of heating. Through this step, the semiconductor device 100 is obtained. The plurality of press-bonded bodies 6 can be collectively heated in one heating furnace 60. When a plurality of pressure-bonded bodies are collectively pressed using a pressing member, it is difficult to uniformly heat the plurality of pressure-bonded bodies. On the other hand, the heating furnace can easily and uniformly heat a large number of press-bonded bodies, thereby improving productivity. As the heating furnace, a reflow furnace, a pressure oven, or the like can be used.

  When the pressed body is heated under a pressurized atmosphere, the fillet tends to be suppressed as compared with the case where the pressed body is heated and pressed using a pressing member. Fillet suppression is particularly important in the manufacture of miniaturized and high-density semiconductor devices. Here, suppressing the fillet means suppressing the fillet width to a small value, and the fillet width is the length of the adhesive protruding to the outer peripheral portion of the semiconductor device. The fillet width can be measured, for example, by photographing an external appearance image of a semiconductor device with a digital microscope (VHX-5000, manufactured by Keyence Corporation). The length (fillet width) of the adhesive layer protruding from the four sides around the semiconductor chip is measured, and the average value is obtained as the fillet value. The fillet value may be 150 μm or less from the viewpoint of mounting many semiconductor chips on a semiconductor wafer or a printed circuit board.

  The atmosphere in the heating furnace 60 is not particularly limited, but may be air, nitrogen, formic acid, or the like.

  The air pressure in the heating furnace 60 is appropriately set according to the size and number of members to be connected. The pressure for pressurization 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 pressurization is more preferably 0.05 to 0.8 MPa.

(Semiconductor device)
FIGS. 4, 5, 6, and 7 are cross-sectional views showing another embodiment of a semiconductor device that can be manufactured by the method according to the above-described embodiment.

  A semiconductor device 200 shown in FIG. 4 includes a semiconductor chip 1 (first member) having a semiconductor chip body 10, a wired circuit board 2 (second member) having a substrate body 20, and an adhesive interposed therebetween. And an agent layer 40. In the case of the semiconductor device 200, the semiconductor chip has, as a connection portion, a bump 32 arranged on the surface of the semiconductor chip on the wiring circuit board 2 side. The printed circuit board 2 has, as a connecting portion, a bump 33 disposed on the surface of the substrate body 20 on the semiconductor chip side. The bumps 32 of the semiconductor chip 1 and the bumps 33 of the printed circuit board 2 are electrically connected by metal bonding. That is, the semiconductor chip 1 and the printed circuit board 2 are flip-chip connected by the bumps 32 and 33. The bumps 32 and 33 are shielded from the external environment by being sealed by the adhesive layer 40.

  FIGS. 5 and 6 show a CoC type semiconductor device which is a connection body in which semiconductor chips are connected to each other. The configuration of the semiconductor device 300 shown in FIG. 5 is the same as that of the semiconductor device 100 except that two semiconductor chips are flip-chip connected as a first member and a second member via the wiring 15 and the bump 30. It is. The configuration of the semiconductor device 400 shown in FIG. 6 is the same as that of the semiconductor device 200 except that the two semiconductor chips 1 are flip-chip connected via the bumps 32.

  In the semiconductor devices 100, 200, 300, and 400 shown in FIGS. 3 to 6, the connection portion such as the wiring 15 and the bump 32 may be a metal film (for example, gold plating) called a pad, and the post electrode (For example, a copper pillar). For example, one semiconductor chip may have a copper pillar and a connection bump (solder: tin-silver) as a connection portion, and the other semiconductor chip may have a gold plating as a connection portion. In this case, it is sufficient that the connecting portion reaches a temperature equal to or higher than the melting point of the solder having the lowest melting point among the metal materials forming the surface of the connecting portion.

  The semiconductor chip body 10 is not particularly limited, and various semiconductors such as an element semiconductor composed of the same kind of element such as silicon and germanium, and a compound semiconductor such as gallium arsenide and indium phosphide can be used.

  The wiring circuit board is not particularly limited, and has an insulating substrate having glass epoxy, polyimide, polyester, ceramic, epoxy, bismaleimide triazine or the like as a main component as a substrate main body, and a metal layer formed on the surface thereof. A circuit board on which wiring (wiring pattern) is formed by removing unnecessary portions by etching, a circuit board on which wiring (wiring pattern) is formed by metal plating or the like on the surface of the insulating substrate, and a conductive surface on the surface of the insulating substrate A circuit board or the like on which a substance is printed and wiring (wiring pattern) is formed can be used.

  The material of the connection portion is, for example, gold, silver, copper, solder (main components are, for example, tin-silver, tin-lead, tin-bismuth, tin-copper, tin-silver-copper), tin, nickel, and the like. Contains metal as a main component. The connecting portion may be composed of only a single component, or may be composed of a plurality of components. The connection portion may have a structure in which these metals are stacked. Among metal materials, copper and solder are relatively inexpensive. From the viewpoint of improving connection reliability and suppressing warpage, the connection portion may include solder.

  Among the above metals, gold, silver, and copper are preferable, and silver and copper are more preferable, from the viewpoint of forming a package having excellent electrical and thermal conductivity of the connection portion. From the viewpoint of reducing the cost of the package, silver, copper and solder are preferred, copper and solder are more preferred, and solder is even more preferred, based on being inexpensive. When an oxide film is formed on the surface of the metal at room temperature, the productivity may decrease, or the cost may increase.From the viewpoint of suppressing the formation of the oxide film, gold, silver, copper, and solder are preferable, and gold, Silver and solder are more preferred, and gold and silver are even more preferred.

  A metal layer mainly composed of gold, silver, copper, solder (for example, tin-silver, tin-lead, tin-bismuth, tin-copper), tin, nickel, or the like on the surface of the connection portion May be formed, for example, by plating. This metal layer may be composed of only a single component, or may be composed of a plurality of components. The metal layer may have a structure in which a single layer or a plurality of metal layers are stacked.

  Semiconductor devices (packages) such as the semiconductor devices 100, 200, 300, and 400 are stacked and gold, silver, copper, and solder (main components are, for example, tin-silver, tin-lead, tin-bismuth, and tin-tin). It may be electrically connected by copper, tin-silver-copper), tin, nickel or the like. The metal for the connection may be copper or solder, which is relatively inexpensive. For example, as in the case of TSV technology, an adhesive layer may be flip-chip connected or laminated between semiconductor chips to form a hole penetrating the semiconductor chip and connected to an electrode on the pattern surface.

  FIG. 7 is a sectional view showing another embodiment of the semiconductor device. The semiconductor device 500 illustrated in FIG. 7 has a TSV structure in which a plurality of semiconductor chips are stacked. In the semiconductor device 500 shown in FIG. 7, the wiring 15 formed on the interposer main body 50 as a printed circuit board is connected to the bump 30 of the semiconductor chip 1, so that the semiconductor chip 1 and the interposer 5 are flip-chip connected. It is connected. An adhesive layer 40 is interposed between the semiconductor chip 1 and the interposer 5. The semiconductor chip 1 is repeatedly laminated on the surface of the semiconductor chip 1 opposite to the interposer 5 via the wiring 15, the bump 30, and the adhesive layer 40. The wirings 15 on the pattern surface on the front and back sides of the semiconductor chip 1 are connected to each other by through electrodes 34 filled in holes passing through the inside of the semiconductor chip body 10. As a material of the through electrode 34, copper, aluminum, or the like can be used.

  According to the semiconductor device having a TSV (Through-Silicon Via) structure as illustrated in FIG. 7, a signal can be obtained even from the back surface of a semiconductor chip that is not normally used. Furthermore, since the penetrating electrodes 34 pass vertically through the semiconductor chip 1, the distance between the opposing semiconductor chips 1 and the distance between the semiconductor chip 1 and the interposer 5 are shortened, and flexible connection is possible.

  In the case of the semiconductor device 500 of FIG. 7, a plurality of semiconductor chips 1 are stacked one by one and temporarily press-bonded sequentially, and then a press-bonded body is obtained in a second press-bonding step, and finally, the plurality of semiconductor chips are pressed at once. Heating may be performed under an atmosphere.

  In a bump forming method with a high degree of freedom, such as an area bump chip technique, a semiconductor chip can be directly mounted on a motherboard without an interposer. The adhesive of the present embodiment can be applied to a case where such a semiconductor chip is directly mounted on a motherboard. Note that the adhesive of the present embodiment can also be applied to a case where two printed circuit boards are stacked and a gap between the boards is sealed.

  As another example of a semiconductor device having a multi-layer semiconductor chip, there is a chip stack type package and a POP (Package On Package), which can also be manufactured by the same method as the TSV.

(adhesive)
The adhesive of the present embodiment is a semiconductor adhesive used in the above-described method for manufacturing a semiconductor device, and contains an epoxy resin, a curing agent, and a flux agent.

  The epoxy resin is not particularly limited as long as it has two or more epoxy groups in a molecule. As the epoxy resin, use bisphenol A type, bisphenol F type, naphthalene type, phenol novolak type, cresol novolak type, phenol aralkyl type, biphenyl type, triphenylmethane type, dicyclopentadiene type, various polyfunctional epoxy resins, etc. Can be. 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 the present specification, the weight average molecular weight means a value in terms of standard polystyrene measured by gel permeation chromatography (GPC).

  In the case where the temperature at the time of connection is 250 ° C., the epoxy resin has a thermogravimetric reduction rate of 5% or less at 250 ° C. from the viewpoint of suppressing the generation of volatile components by the decomposition at the time of connection at a high temperature. In the case of 300 ° C., it is preferable to use an epoxy resin having a thermal weight loss rate of 5% or less at 300 ° C.

  The content of the epoxy resin is, for example, 5 to 75% by mass, preferably 10 to 50% by mass, and more preferably 15 to 35% by mass, based on the total amount of the adhesive. In the present specification, “the total amount of the adhesive” means the total amount of components other than the organic solvent used for preparing the resin varnish described below.

  Examples of the curing agent include a phenol 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. From the viewpoint of exhibiting flux activity that suppresses the formation of an oxide film at the connection part and improving the connection reliability and insulation reliability, the curing agent is a phenolic resin-based curing agent, an acid anhydride-based curing agent, or an amine. It preferably contains at least one member selected from a series curing agent and an imidazole series curing agent, and more preferably contains an imidazole series curing agent. Hereinafter, each curing agent will be described.

  The phenolic resin-based curing agent is not particularly limited as long as it has two or more phenolic hydroxyl groups in the molecule. Examples thereof include phenol novolak, cresol novolak, phenol aralkyl resin, cresol naphthol formaldehyde polycondensate, Examples include triphenylmethane-type polyfunctional phenols and various polyfunctional phenol resins. These can be used alone or as a mixture of two or more.

  The equivalent ratio of the phenolic resin-based curing agent to the epoxy resin (phenolic hydroxyl group / epoxy group, molar ratio) is preferably from 0.3 to 1.5 from the viewpoint of good curability, adhesiveness, and storage stability. 0.4 to 1.0 is more preferable, and 0.5 to 1.0 is still more preferable. When the equivalent ratio is 0.3 or more, the curability tends to be improved and the adhesive strength tends to be improved. When the equivalent ratio is 1.5 or less, unreacted phenolic hydroxyl groups do not remain excessively, and the water absorption rate is reduced. It tends to be kept low and the insulation reliability tends to improve. When the equivalent ratio is 0.3 to 1.5, it is easy to adjust the gel time to an appropriate range.

  Examples of the acid anhydride-based curing agent include methylcyclohexanetetracarboxylic dianhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic dianhydride, and ethylene glycol bisanhydrotrimellitate. These can be used alone or as a mixture of two or more.

  The equivalent ratio of the acid anhydride-based curing agent to the epoxy resin (acid anhydride group / epoxy group, molar ratio) is preferably 0.3 to 1.5 from the viewpoints of good curability, adhesiveness, and storage stability. , 0.4 to 1.0, more preferably 0.5 to 1.0. When the equivalent ratio is 0.3 or more, the curability tends to be improved and the adhesive strength tends to be improved. When the equivalent ratio is 1.5 or less, the unreacted acid anhydride does not remain excessively, and the water absorption rate is reduced. It tends to be kept low and the insulation reliability tends to improve. When the equivalent ratio is 0.3 to 1.5, it is easy to adjust the gel time to an appropriate range.

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

  The equivalent ratio of the amine-based curing agent to the epoxy resin (amine / epoxy group, molar ratio) is preferably from 0.3 to 1.5, and more preferably from 0.4 to 1 from the viewpoints of good curability, adhesion and storage stability. 0.0 is more preferable, and 0.5 to 1.0 is further preferable. When the equivalent ratio is 0.3 or more, the curability tends to be improved and the adhesive strength tends to be improved. When the equivalent ratio is 1.5 or less, the unreacted amine does not remain excessively and the insulation reliability is improved. Tend to. When the equivalent ratio is 0.3 to 1.5, it is easy to adjust the gel time to an appropriate range.

  Examples of the imidazole-based curing agent include, for example, 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- Examples include phenyl-4-methyl-5-hydroxymethylimidazole, and adducts of epoxy resins and imidazoles. From the viewpoint of excellent curability, 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 Adduct of 2-phenylimidazole isocyanuric acid, 2-phenyl-4,5-dihydroxymethylimidazole and 2-phenyl-4- From chill-5-hydroxymethylimidazole may select the imidazole curing agent. These can be used alone or in combination of two or more. Microcapsules containing these can also be used as a latent curing agent.

  The content of the imidazole-based curing agent is preferably from 0.1 to 20 parts by mass, more preferably from 0.1 to 10 parts by mass, and even more preferably from 3.2 to 5.5 parts by mass, per 100 parts by mass of the epoxy resin. preferable. When the content of the imidazole-based curing agent is 0.1 parts by mass or more, the curability tends to be improved, and when the content is 20 parts by mass or less, the adhesive is not cured before metal bonding is formed, Connection failures tend to be less likely to occur. When the content of the imidazole-based curing agent is 0.1 to 20 parts by mass, the gel time can be easily adjusted to an appropriate range.

  Examples of the phosphine-based curing agent include triphenylphosphine, tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium tetra (4-methylphenyl) borate, and tetraphenylphosphonium (4-fluorophenyl) borate.

  The content of the phosphine-based curing agent is preferably from 0.1 to 10 parts by mass, more preferably from 0.1 to 5 parts by mass, based on 100 parts by mass of the epoxy 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 the content is 10 parts by mass or less, the adhesive is not cured before metal bonding is formed, Connection failures tend to be less likely to occur.

  The phenolic resin-based curing agent, the acid anhydride-based curing agent, and the amine-based curing agent can be used each alone or as a mixture of two or more. The imidazole-based curing agent and the phosphine-based curing agent may be used alone, but may be used together with a phenolic resin-based curing agent, an acid anhydride-based curing agent, or an amine-based curing agent.

  The flux agent is, for example, a compound having a group represented by the formula (1). The fluxing agent can be a single compound of the formula (1) or a combination of two or more compounds.

In the 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 is preferably one that does not easily react with other components (epoxy resin), and is preferably an alkyl group, a hydroxyl group or an alkoxyl group, and more preferably an alkyl group.

  As the alkyl group, an alkyl group having 1 to 10 carbon atoms is preferable, and an alkyl group having 1 to 5 carbon atoms is more preferable. Basically, the larger the number of electron donating groups, the stronger the electron donating property and the more preferable, but the steric hindrance increases. Therefore, the alkyl group may be linear or branched, but is preferably linear. When the alkyl group is linear, the number of carbon atoms of the alkyl group is preferably equal to or less than that of the main chain containing carboxylic acid from the viewpoint of steric hindrance.

  As the alkoxy group, an alkoxy group having 1 to 10 carbon atoms is preferable, and an alkoxy group having 1 to 5 carbon atoms is more preferable. The larger the number of electron donating groups, the stronger the electron donating property, but the greater the steric hindrance. Therefore, the alkyl group portion of the alkoxy group may be linear or branched, and is preferably linear. When the alkyl group portion of the alkoxy group is linear, the number of carbon atoms is preferably equal to or less than that of the main chain containing a carboxylic acid from the viewpoint of steric hindrance.

  Examples of the alkylamino group include a monoalkylamino group and a dialkylamino group. As the monoalkylamino group, a monoalkylamino group having 1 to 10 carbon atoms is preferable, and a monoalkylamino group having 1 to 5 carbon atoms is more preferable. The alkyl group portion of the monoalkylamino group may be linear or branched, and is preferably linear.

  As the dialkylamino group, a dialkylamino group having 1 to 20 carbon atoms is preferable, and a dialkylamino group having 1 to 10 carbon atoms is more preferable. The alkyl group portion of the dialkylamino group may be linear or branched, and is preferably linear.

  The fluxing agent is preferably a compound having two carboxyl groups (dicarboxylic acid). A compound having two carboxyl groups is less likely to volatilize even at a high temperature at the time of connection and can further suppress the generation of voids, as compared with a compound having one carboxyl group (monocarboxylic acid). In addition, when a compound having two carboxyl groups is used, an increase in the viscosity of the adhesive during storage and connection work can be further suppressed as compared with a case where a compound having three or more carboxyl groups is used. . As a result, the connection reliability of the semiconductor device can be further improved.

As the flux agent, a compound represented by the following formula (2) can be suitably used. According to the flux agent comprising the compound represented by the following formula (2), the reflow resistance and connection reliability of the semiconductor device can be further improved.

In the formula (2), R ¹ represents an electron donating group, R ² represents a hydrogen atom or an electron donating group, and n represents an integer of 0 to 10.

  N in the formula (2) is preferably an integer of 2 to 10, and more preferably an integer of 2 to 8. When n is 10 or less, the flux activity is developed in a shorter time, and even more particularly when the connection time is short, more excellent connection reliability can be obtained. Further, when n is 2 or more, volatilization hardly occurs even at a high temperature at the time of connection, and the generation of voids can be further suppressed.

R ² may be a hydrogen atom or an electron donating group. When R ² is a hydrogen atom, the melting point tends to be low, and connection reliability (solder wettability) may be improved. For example, a flux agent having the same methyl group in both R ¹ and R ² has a higher melting point than one having a methyl group in one (R ¹ or R ² ), and the wettability of the solder depends on the melting point (eg, (At 150 ° C. or higher).

  Examples of the flux agent include, for example, an electron-donating group at the 2-position of a dicarboxylic acid selected from succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecandioic acid and dodecandioic acid. Substituted compounds can be used.

  The melting point of the flux agent is preferably 150 ° C. or lower, more preferably 140 ° C. or lower, and further preferably 130 ° C. or lower. Such a flux agent exhibits sufficient flux activity before a curing reaction between the epoxy resin and the curing agent occurs. Therefore, according to the adhesive containing such a flux agent, a semiconductor device having more excellent connection reliability can be realized. The melting point of the flux agent is preferably solid at room temperature, preferably 25 ° C. or higher, more preferably 50 ° C. or higher. The melting point of the flux agent can be measured, for example, by using a double-tube thermometer equipped with a capillary tube filled with a sample and heating with a warm bath.

  The melting point of the flux agent contained in the adhesive of the present embodiment is preferably higher than the stage temperature of the pressing device for forming the temporary press-bonded body. When the melting point of the flux agent is higher than the stage temperature of the pressing device, it is possible to manufacture a semiconductor device having excellent connection reliability even if the heat histories at the beginning and end of the press bonding are different.

  The content of the flux agent is preferably 0.5 to 10% by mass, more preferably 0.5 to 5% by mass, based on the total amount of the adhesive.

  The adhesive may contain a polymer component having a weight average molecular weight of 10,000 or more, if necessary. An adhesive containing a polymer component having a weight average molecular weight of 10,000 or more is more excellent in heat resistance and film formability.

  As the polymer component having a weight average molecular weight of 10,000 or more, for example, phenoxy resin, polyimide resin, polyamide resin, polycarbodiimide resin, cyanate ester resin, acrylic resin, polyester resin, polyethylene resin, polyether sulfone resin, polyetherimide resin , Polyvinyl acetal resin, urethane resin and acrylic rubber. Among these, phenoxy resins, polyimide resins, acrylic rubbers, cyanate ester resins, and polycarbodiimide resins are preferable, and phenoxy resins, polyimide resins, and acrylic rubbers are more preferable from the viewpoint of excellent heat resistance and film formability. These polymer components having a weight average molecular weight of 10,000 or more can be used alone or as a mixture or copolymer of two or more. However, the polymer component having a weight average molecular weight of 10,000 or more does not include the above-described epoxy resin.

  The glass transition temperature (Tg) of the polymer component having a weight average molecular weight of 10,000 or more may be 50 ° C or more and 200 ° C or less, from the viewpoint of excellent adhesion of the adhesive to a printed circuit board or a semiconductor chip. The temperature is preferably from 180C to 180C, more preferably from 50C to 150C. When the Tg of the polymer component having a weight average molecular weight of 10,000 or more is 50 ° C. or more, the tack (viscosity) force of the adhesive tends to be moderately weak. When the Tg of the polymer component having a weight average molecular weight of 10,000 or more is 200 ° C. or less, the adhesive can easily embed bumps of the semiconductor chip, electrodes and wiring patterns formed on the wiring circuit board, and the effect of suppressing voids. Tend to be relatively large. Here, Tg is measured using a DSC (Model DSC-7, manufactured by PerkinElmer Co., Ltd.) under the conditions of a sample amount of 10 mg, a temperature rising rate of 10 ° C./min, and an air atmosphere.

  The weight average molecular weight of the polymer component is 10,000 or more. In order to exhibit good film-forming properties by itself, the weight average molecular weight of the polymer component is preferably 30,000 or more, more preferably 40000 or more, and still more preferably 50,000 or more.

When the adhesive is a weight average molecular weight contains 10000 or more polymeric components, the ratio _C a / _{C d} (mass content _{C a} of the epoxy resin weight average molecular weight to the content _{C d} of 10000 or more polymeric components Ratio) is preferably 0.01 to 5, more preferably 0.05 to 3, and even more preferably 0.1 to 2. By setting the ratio C _a / C _d to 0.01 or more, better curability and adhesive strength are obtained, and by setting the ratio C _a / C _d to 5 or less, better film formability is obtained. .

  Even if the adhesive contains a filler for controlling the viscosity and physical properties of the cured product, and for suppressing generation of voids and moisture absorption when connecting the semiconductor chips to each other or the semiconductor chip and the wiring circuit board, Good. The filler may be an insulating inorganic filler, and examples thereof include glass, silica, alumina, titanium oxide, carbon black, mica, and boron nitride. Among these, a filler selected from silica, alumina, titanium oxide, and boron nitride, or silica, alumina, and boron nitride may be used. The filler may be a whisker, examples of which include aluminum borate, aluminum titanate, zinc oxide, calcium silicate, magnesium sulfate, and boron nitride. The filler may be a resin filler, and examples thereof include polyurethane, polyimide, methyl methacrylate resin, methyl methacrylate-butadiene-styrene copolymer resin (MBS). These fillers can be used alone or in combination of two or more. The shape, particle size, and content of the filler are not particularly limited.

  The filler may be one whose physical properties are appropriately adjusted by surface treatment.

  From the viewpoint of adjusting the minimum melt viscosity to an appropriate range, the content of the filler is preferably from 10 to 80% by mass, more preferably from 15 to 60% by mass, based on the total amount of the adhesive.

  The adhesive may further include other components such as 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. What is necessary is just to adjust suitably these compounding quantities so that the effect of each additive may be exhibited.

  The adhesive may be in the form of a film from the viewpoint of improving the production efficiency of the semiconductor device. The film adhesive can be produced by a method in which a resin varnish containing a thermosetting resin, a curing agent, and other components as necessary is applied to a device film, and the coating film is dried.

  The resin varnish is prepared by mixing an epoxy resin, a curing agent and a fluxing agent, and a polymer component having a weight-average molecular weight of 10,000 or more and a filler added as necessary with an organic solvent, and dissolving or mixing them by stirring or kneading. Prepared by dispersing. The resin varnish is applied on the release-treated base film using, for example, a knife coater, a roll coater, an applicator, a die coater, or a comma coater. Thereafter, the organic solvent is reduced from the coating film of the resin varnish by heating, that is, the coating film is dried to form a film-like adhesive on the base film. A film of resin varnish may be formed on a semiconductor wafer or the like by a method such as spin coating, and then a film-like adhesive may be formed on the semiconductor wafer by a method of drying a coating film.

  As the organic solvent used for preparing the resin varnish, those having characteristics capable of uniformly dissolving or dispersing each component are preferable, for example, dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, dimethylsulfoxide, diethylene glycol dimethyl ether, Examples include 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. Stirring and kneading at the time of preparing the resin varnish can be performed using, for example, a stirrer, a grinder, a three-roll mill, a ball mill, a bead mill, or a homodisper.

  The substrate film is not particularly limited as long as it has heat resistance enough to withstand the heating conditions when the organic solvent is volatilized.Polypropylene film, polyolefin film such as polymethylpentene film, polyethylene terephthalate film, polyethylene naphthalate Examples thereof include a polyester film such as a film, a polyimide film, and a polyetherimide film. The base film is not limited to a single layer made of these films, and may be a multilayer film made of two or more materials.

  The conditions for volatilizing the organic solvent from the resin varnish after application may be, specifically, heating at 50 to 200 ° C. for 0.1 to 90 minutes. The organic solvent may be removed until the residual amount becomes 1.5% by mass or less as long as the void after the mounting and the viscosity adjustment are not substantially affected.

  The minimum melt viscosity of the adhesive is not less than 1500 Pa · s and not more than 3500 Pa · s. When the minimum melt viscosity of the adhesive is in this range, voids hardly remain in the adhesive layer of the semiconductor device. The melt viscosity of the adhesive can be adjusted to a range of 1500 Pa · s or more and 3500 Pa · s or less depending on the content of the filler, the content of the polymer component, and the like.

  The minimum melt viscosity of the adhesive is determined by increasing the viscoelasticity of the adhesive while raising the temperature in a temperature range of 35 to 150 ° C. while giving 1% strain to the test piece under the conditions of a temperature rising rate of 10 ° C./min and a frequency of 10 Hz. This is the minimum value of the viscosity in the relationship between the viscosity (complex viscosity) obtained when measuring and the temperature. As a test piece for viscoelasticity measurement, for example, a laminate obtained by laminating a plurality of film-like adhesives so as to have a thickness of 300 to 450 μm may be used. As the viscosity measuring device, for example, ARES manufactured by TA Instruments can be used.

  The gel time of the adhesive according to the present embodiment is 10 seconds or more and 30 seconds or less at 200 ° C. When the gel time is in this range, voids are unlikely to remain, and good connection reliability can be easily secured. The gel time of the adhesive can be adjusted to a range of 10 seconds or more and 30 seconds or less depending on the type and content of the curing agent.

  Here, the gel time is the time from placing the film adhesive on a hot plate at 200 ° C. until the adhesive gels. Details of the method for measuring the gel time will be described later.

  Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

The materials used in each example and comparative example are as follows.
(I) Epoxy resin / EP1032H60: Trifunctional phenol skeleton-containing polyfunctional solid epoxy resin (manufactured by Mitsubishi Chemical Corporation, trade name "EP1032H60", weight average molecular weight: 800 to 2000)
-YL983U: Bisphenol F type liquid epoxy resin (manufactured by Mitsubishi Chemical Corporation, trade name "YL983U", weight average molecular weight: about 336)
-YL7175: flexible epoxy resin (manufactured by Mitsubishi Chemical Corporation, trade name "YL7175", weight average molecular weight: 1,000 to 5,000)
(Ii) Curing agent · 2MAOK-PW: 2,4-diamino-6- [2′-methylimidazolyl- (1 ′)]-ethyl-s-triazine isocyanuric acid adduct (trade name, manufactured by Shikoku Chemical Industry Co., Ltd.) "2MAOK-PW")
(Iii) Flux agent / glutaric acid (manufactured by Tokyo Chemical Industry Co., Ltd., melting point: about 98 ° C.)
(Iv) Polymer component having a molecular weight of 10,000 or more: ZX1356-2: phenoxy resin (trade name “ZX1356-2”, manufactured by Shin Nikka Epoxy Manufacturing Co., Ltd., Tg: about 71 ° C., weight average molecular weight: about 63000)
(V) Filler (inorganic filler)
・ SE2050: Silica filler (trade name “SE2050”, manufactured by Admatechs Co., Ltd., average particle size 0.5 μm)
-SE2050-SEJ: Epoxysilane-treated silica filler (trade name "SE2050-SEJ", manufactured by Admatechs Co., Ltd., average particle size 0.5 m)
-SM nanosilica: Acrylic surface-treated nanosilica filler (trade name "YA050C-SM" manufactured by Admatechs Co., Ltd., average particle size about 50 nm)
SM nano-silica 2: Acrylic surface-treated nano-silica filler (trade name “YA180C-SM”, manufactured by Admatechs Co., Ltd., average particle size about 180 nm)
(Organic filler)
-EXL2655: core-shell type organic fine particles (trade name "EXL2655", manufactured by Dow Chemical Japan Co., Ltd.)

(1) Production of film adhesive (Example 1)
3 g of epoxy resin (2.4 g of “EP1032”, 0.5 g of “YL983”, 0.2 g of “YL7175”), 0.1 g of curing agent “2MAOK”, and 0.1 g of glutaric acid (0.7 mmol) ), 1.9 g of inorganic filler (0.4 g of “SE2050”, 0.38 g of “SE2050-SEJ”, 1.1 g of “SM nanosilica”), 0.3 g of organic filler (EXL-2655), and Methyl ethyl ketone (the amount of the solid content becomes 63% by mass) is charged in a vessel of a bead mill (Fritsch Japan K.K., planetary pulverizer P-7), and beads having a diameter of 0.8 mm and beads having a diameter of 2.0 mm. Was added at the same weight as the solid content, and the mixture was stirred for 30 minutes. Next, 1.7 g of a phenoxy resin (ZX1356) was added, and the mixture was again stirred with a bead mill for 30 minutes. Thereafter, the beads used for stirring were removed by filtration to obtain a resin varnish.

  The obtained resin varnish is applied on a base film (manufactured by Teijin Film Solutions Co., Ltd., trade name "Purex A53") using a small precision coating apparatus (manufactured by Yasui Seiki Co., Ltd.), and the coating film is formed. It was dried at 70 ° C. for 10 minutes using a clean oven (manufactured by Espec Corporation) to obtain a film adhesive (thickness: 0.045 mm).

(Examples 2 to 4 and Comparative Examples 1 to 5)
Except having changed the composition of the used material as shown in the following Table 1, it carried out similarly to Example 1, and produced the film adhesive of Examples 2-4 and Comparative Examples 1-5.

(2) Minimum Melt Viscosity Measurement The minimum melt viscosity of the film adhesive was measured using a rotary dynamic viscoelasticity measuring device (ARES, manufactured by TA Instruments Co., Ltd.). First, a test piece having a total thickness of 400 μm was obtained by laminating a plurality of film adhesives at 80 ° C. The obtained test piece was sandwiched between two circular measuring jigs having a diameter of 8 mm, and the viscosity was measured while raising the temperature. The measurement mode was a dynamic temperature ramp, the frequency was 10 Hz, the measurement start temperature was 35 ° C., the measurement end temperature was 150 ° C., and the heating rate was 10 ° C./min. The measurement was performed while giving a 1% strain to the test piece. The lowest value of the measured viscosity was recorded as the lowest melt viscosity.

(3) Measurement of gel time A plurality of film-like adhesives were laminated at 80 ° C. to make the overall thickness 120 μm. A test piece having a size of 11 mm square was cut out from the formed laminate film. The obtained test piece was placed on a hot plate at 200 ° C., and the test piece was stirred with a stir bar so as to draw a small circle. When the test piece began to thicken, the whole was stirred, and the stirring was continued until the test piece gelled and lost flowability. The time from when the test piece was placed on the hot plate to when the test piece gelled and lost the fluidity was measured in units of 1 second as a gel time. The same measurement is performed twice, and when the high value is less than or equal to 1.05 times the low value among the two measured values obtained by the two measurements, the average value of the two measured values is calculated for the test piece. Recorded as gel time. If the higher of the two measurements is greater than 1.05 times the lower value, a third measurement is performed and the average of the three measurements from the three measurements is taken as the gel time of the test piece. Recorded as.

(4) Fabrication of semiconductor device (Examples 1-4 and Comparative Examples 1-5)
Formation of temporary pressure-bonded body The prepared film adhesive was cut out to prepare a film adhesive having a size of 8 mm x 8 mm x 0.045 mm in thickness. This was affixed to a semiconductor chip (10 mm, thickness 0.1 mm, connection metal: Au, product name: WALTS-TEG IP80, manufactured by Waltz Co., Ltd.). There, a semiconductor chip with solder bumps (chip size: 7.3 mm × 7.3 mm × thickness 0.05 mm, solder bump melting point: about 220 ° C., bump height: about 45 μm in total of copper pillar and solder, number of bumps 1048) A pin, a pitch of 80 μm, and a product name: WALTS-TEG CC80, manufactured by Waltz Co., Ltd.) were affixed to obtain a laminate. The laminate is placed on a stage at 80 ° C. of a flip chip bonder (FCB3, manufactured by Panasonic Corporation) having a stage and a crimp head, and the laminate is pressed with a load of 25 N for 3 seconds by a hot press sandwiched between the stage and the crimp head. Was heated to 80 ° C. while applying pressure to obtain a temporary pressure-bonded body.

Formation of a crimped body The obtained temporary crimped body is moved on a stage of another flip chip bonder (FCB3, manufactured by Panasonic Corporation) at 80 ° C, and is pressed with a load of 25N by being sandwiched between the stage and a crimping head. While pressing at 230 ° C. for 1 second, a pressed body was obtained.

Heating of the press-bonded body under a pressurized atmosphere The press-pressed body was placed in an oven of a pressurized oven device (manufactured by NTT Advanced Technology Corporation). The pressure in the oven was set to 0.7 MPa, and the temperature was raised from room temperature to 175 ° C. at a rate of 20 ° C./min. Next, the pressure-bonded body was heated under a pressurized atmosphere for 5 minutes while maintaining the pressure and the temperature to obtain a semiconductor device sample for evaluation.

(5) Evaluation of Void The appearance image of the sample was photographed by an ultrasonic imaging apparatus (product name: Insight-300, manufactured by Insight Co., Ltd.). From the obtained image, the portion of the adhesive layer on the chip was captured by a scanner (product name: GT-9300UF, manufactured by Seiko Epson Corporation). Using the image processing software Adobe Photoshop, the void portion was identified by color tone correction and two gradations, and the ratio of the void portion (void generation rate) was calculated by a histogram, with the area of the adhesive layer being 100%. The state of generation of voids was evaluated according to the following criteria. The results are shown in Table 1.
A: Void generation rate is 5% or less B: Void generation rate is more than 5%

(6) Connection evaluation The possibility of initial conduction of the sample was measured using a multimeter (product name: R6871E, manufactured by Advantest Corporation). Connectivity was determined according to the following criteria. The results are shown in Table 1.
A: Connection resistance value is 10.0 to 15.0Ω.
B: Connection resistance value is larger than 15.0Ω and smaller than 10.0Ω or connection resistance value is not measured due to poor connection

  When the adhesives of Examples 1 to 4 were used, it was confirmed that voids were suppressed and the connectivity was good in the obtained semiconductor devices. When the adhesives of Comparative Examples 1, 4, and 5 were used, voids occurred in the obtained semiconductor devices. When the adhesives of Comparative Examples 2 and 3 were used, it was confirmed that the resulting semiconductor devices had poor connectivity.

DESCRIPTION OF SYMBOLS 1 ... Semiconductor chip, 2 ... Wiring circuit board, 3 ... Laminated body, 4 ... Temporarily crimped body, 5 ... Interposer, 6 ... Crimped body, 10 ... Semiconductor chip body, 15, 16 ... Wiring, 20 ... Board body, 30 , 32, 33 ... bump, 34 ... penetrating electrode, 40 ... adhesive layer, 41, 44 ... pressure bonding head, 42, 45 ... stage, 43, 46 ... pressing device, 50 ... interposer body, 60 ... heating furnace, 100 , 200, 300, 400, 500 ... semiconductor devices.

Claims (8)

The first member having the connection portion and the second member having the connection portion are 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 via an adhesive. A step of obtaining a temporary press-bonded body in which the connection portion of the first member and the connection portion of the second member are arranged to face each other by temporarily pressing at a temperature;
The temporary compression-bonded body is pressurized while being heated to a temperature equal to or higher than at least one of the melting points of the connection portion of the first member or the connection portion of the second member, and the connection portion of the first member and A step of obtaining a crimped body in which the connection portion of the second member is joined,
With
The first member is a semiconductor chip or a semiconductor wafer, the second member is a printed circuit board, a semiconductor chip or a semiconductor wafer,
The adhesive contains an epoxy resin, a curing agent and a flux agent,
The adhesive has a minimum melt viscosity of 1500 Pa · s or more and 3500 Pa · s or less, and shows a gel time of 10 seconds or more and 30 seconds or less at 200 ° C.
A method for manufacturing a semiconductor device.   The method according to claim 1, further comprising heating the press body under a pressurized atmosphere.   In the step of obtaining the crimped body by applying pressure while 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, The method according to claim 1, wherein the temporary pressure-bonded body is heated and pressed by sandwiching the temporary pressure-bonded body between the pair of pressing members. Contains epoxy resin, curing agent and fluxing agent,
Shows a minimum melt viscosity of 1500 Pa · s or more and 3500 Pa · s or less, and shows a gel time of 10 seconds or more and 30 seconds or less at 200 ° C.
An adhesive for semiconductors to be used as an adhesive in the method according to claim 1.   The adhesive for semiconductors according to claim 4, wherein the epoxy resin has a weight average molecular weight of less than 10,000.   The adhesive for semiconductors according to claim 4 or 5, further comprising a polymer component having a weight average molecular weight of 10,000 or more.   The adhesive for semiconductors according to claim 6, wherein the polymer component has a weight average molecular weight of 30,000 or more, and the glass transition temperature of the polymer component is 200 ° C or less. The semiconductor adhesive according to any one of claims 4 to 7, which is a film adhesive.

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