JP2017220519A - Semiconductor device manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device manufacturing method which can reduce voids in a semiconductor device and inhibit a fillet.SOLUTION: In a semiconductor device where a semiconductor chip 2 and a wiring circuit board, or semiconductor chips 2 are electrically connected with their connection parts 5 by metal joining in a state where a film semiconductor adhesive is sandwiched, a thickness T(μm) of the film semiconductor adhesive satisfies the following conditions 1, 2. Condition 1: T=X{α+(0.5β)}; and condition 2: 1.06≤X≤1.36 (where α: a length 6 of a joining part 4 of the semiconductor chip 2, which does not form metal joining; and β: a length 7 of a joining part 5 of a semiconductor chip 2, which forms metal joining).SELECTED DRAWING: Figure 6

Description

  The present invention relates to a method for manufacturing a semiconductor device.

  Conventionally, a wire bonding method using a fine metal wire such as a gold wire has been widely applied to connect a semiconductor chip and a substrate, but in order to meet demands for high functionality, high integration, high speed, etc. for semiconductor devices, A flip chip connection method (FC connection method) in which conductive protrusions called bumps are formed on a semiconductor chip or a substrate to directly connect the semiconductor chip and the substrate is becoming widespread.

  Flip chip connection methods include metal bonding using solder, tin, gold, silver, copper, etc., metal bonding by applying ultrasonic vibration, method of maintaining mechanical contact by the shrinkage force of the resin, etc. However, from the viewpoint of the reliability of the connection portion, a method of metal bonding using solder, tin, gold, silver, copper, or the like is common.

  For example, in connection between a semiconductor chip and a substrate, a COB (Chip On Board) type connection method that is actively used in BGA (Ball Grid Array), CSP (Chip Size Package), etc. is also a flip chip connection method. . The flip chip connection method is also widely used in a COC (Chip On Chip) type connection method in which bumps or wirings are formed on semiconductor chips to connect the semiconductor chips (see, for example, Patent Document 1). ).

  For packages that are strongly required to be further reduced in size, thickness, and functionality, there are chip stack type packages, POP (Package On Package), TSV (Through-Silicon Via), etc., in which the above connection methods are stacked and multi-staged. It has begun to spread widely. Since the package can be made smaller by arranging it in a three-dimensional shape instead of a flat shape, these technologies are frequently used, and it is also effective for improving semiconductor performance, reducing noise, reducing mounting area, and reducing power consumption. It is attracting attention as a wiring technology.

  From the viewpoint of improving productivity, COW (Chip On Wafer) is a method of manufacturing a semiconductor package by bonding a semiconductor chip onto a wafer after being crimped (connected), and semiconductor package after being individually bonded after connecting (bonding) the wafers together. A WOW (Wafer On Wafer) for producing the film is also attracting attention. Further, from the same point of view, a gang bonding method in which a plurality of chips are aligned on a wafer or a map substrate and temporarily press-bonded, and then the plurality of chips are collectively pressure-bonded to ensure connection is also attracting attention. .

JP 2011-29232 A

  As the flip chip package assembly method described above, for example, the following method can be considered. First, a semiconductor chip to which a film-like semiconductor adhesive is supplied from a diced wafer is picked up by a collet and supplied to a pressing member for pressure bonding. Next, after positioning between the chip and the chip or between the chip and the substrate, they are pressure-bonded to each other, and the temperature of the pressure member for pressing so as to reach the melting point or more of the connection part between the chip and the chip or between the chip and the substrate. And a metal bond is formed at the connecting portion.

  At the time of pressure bonding, a step of filling a chip-chip or chip-substrate with a semiconductor adhesive and a step of metal-bonding a chip-chip or chip-substrate connection portion are simultaneously performed. At this time, if the thickness of the semiconductor adhesive is small with respect to the distance between the chip and the chip or between the chip and the substrate, voids (bubbles) are likely to be generated in the semiconductor adhesive layer.

  In addition, since semiconductor devices tend to be smaller and thinner, it is necessary to suppress the fillet after crimping (the portion where the semiconductor adhesive has flowed during crimping and has flowed out around the semiconductor chip). However, if the thickness of the semiconductor adhesive is reduced to reduce the fillet (the amount of the semiconductor adhesive is reduced), there is a problem that the semiconductor adhesive does not flow sufficiently and voids are generated.

  The main object of this invention is to obtain the semiconductor device which suppresses generation | occurrence | production of a void and a fillet regarding the method of manufacturing the semiconductor device using a film-form semiconductor adhesive.

One aspect of the present invention includes a semiconductor device having a connection portion and a printed circuit board having a connection portion, and each of the connection portions is electrically connected to each other, or a plurality of semiconductor chips having connection portions. Each of the connecting portions is electrically connected to each other, wherein the connecting portions are made of metal.
The semiconductor chip and the printed circuit board, or the semiconductor chips, wherein the respective connecting portions are electrically connected by metal bonding in a state where a film-like semiconductor adhesive is interposed therebetween. A device manufacturing method comprising:
By setting the thickness T (μm) of the film-like semiconductor adhesive to T that satisfies the following conditions 1 and 2, semiconductor devices are continuously manufactured.
Condition 1: T = X {α + (0.5β)}
Condition 2: 1.06 ≦ X ≦ 1.36
α: length of the portion where the metal chip is not formed in the connection portion of the semiconductor chip (μm)
β: length of the portion where the metal bond is formed in the connection portion of the semiconductor chip (μm)

  According to the method of manufacturing the semiconductor device, void generation and fillet can be suppressed by setting the thickness of the film-like semiconductor adhesive to T that satisfies the conditions 1 and 2.

  The film-like semiconductor adhesive may be a layer formed of a thermosetting resin composition containing a compound having a weight average molecular weight of 10,000 or less and a curing agent thereof and having a minimum melt viscosity of 5000 Pa · s or less. Good.

  The film-like semiconductor adhesive preferably contains a high molecular weight component having a weight average molecular weight exceeding 10,000, and more preferably having a weight average molecular weight exceeding 30,000. Moreover, it is preferable that the glass transition temperature of the said high molecular weight component is 100 degrees C or less.

  By setting the thickness of the film-like semiconductor adhesive from the length of the connecting portion of the semiconductor chip and using the semiconductor adhesive, a semiconductor device in which generation of voids and fillets are suppressed can be obtained.

Sectional view of connection between semiconductor chip and substrate (example COB). Semiconductor chip indirect group sectional drawing (example COC). Semiconductor chip lamination type sectional view (example TSV). Cross-sectional view of connection between a plurality of semiconductor chips and a substrate (example COB). Cross-sectional view of connection between a plurality of semiconductor chips and an interposer (example COW) Explanatory drawing of the length of a connection part.

  Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments. The upper limit value and the lower limit value of the numerical ranges described in this specification can be arbitrarily combined. Numerical values described in the examples can also be used as the upper limit value or the lower limit value of the numerical range. In this specification, “(meth) acryl” means acryl or methacryl corresponding thereto.

<Semiconductor device>
A semiconductor device obtained by the method for manufacturing a semiconductor device of this embodiment will be described below with reference to FIGS. FIG. 1 shows a cross-sectional structure when a connection is made between a semiconductor chip and a substrate, and FIG. 2 shows a cross-sectional structure when the connection is made between semiconductor chips.

  FIG. 1 is a schematic cross-sectional view showing an embodiment of a semiconductor device. FIG. 1A shows a semiconductor chip 2 and a substrate (circuit wiring board) 3 that face each other, and a connection portion 4 and a wiring that do not form a metal bond and are disposed on the mutually facing surfaces of the semiconductor chip 2 and the substrate 3, respectively. It has a film-like semiconductor adhesive 1 in which a gap between the semiconductor chip 2 and the substrate 3 is filled without any gaps between the connecting portion 5 and the wiring 8 that form a metal bond. The semiconductor chip 2 and the substrate 3 are flip-chip connected by connecting portions 4 and 5 and wirings 8.

  FIG. 1B shows a semiconductor chip 2 and a substrate (circuit wiring board) 3 that face each other, and a connection portion 5 that forms a metal bond with a wiring disposed on the mutually facing surfaces of the semiconductor chip 2 and the substrate 3. The wiring 8 and the film-like semiconductor adhesive 1 filled in the space between the semiconductor chip 2 and the substrate 3 without a gap are provided. The semiconductor chip 2 and the substrate 3 are flip-chip connected by the connection portion 5 and the wiring 8.

  FIG. 2 is a schematic cross-sectional view showing another embodiment of the semiconductor device. FIG. 2 (a) is the same as FIG. 1 (a) except that the two semiconductor chips 2 are flip-chip connected by a connecting portion 4 that does not form a metal bond, a wiring and a connecting portion 5 that forms a metal bond, and a wiring 8. ). FIG. 2B is the same as FIG. 1B except that two semiconductor chips 2 are flip-chip connected by a connection portion 5 and a wiring 8 that form a metal bond with the wiring. As a more specific aspect of FIG. 2A, the upper semiconductor chip 2 in the drawing has a copper pillar as the connection portion 4 and a solder (solder bump) as the connection portion 5, and the lower semiconductor chip in the drawing. A mode in which 2 has a pad (gold plating at a connection portion) as the wiring 8 is exemplified.

  There is no restriction | limiting in particular as the semiconductor chip 2, Various semiconductors, such as an element semiconductor comprised from the same kind of elements, such as silicon and germanium, and compound semiconductors, such as gallium arsenide and indium phosphorus, can be used.

  The substrate 3 is not particularly limited as long as it is a printed circuit board, and does not require a metal layer formed on the surface of an insulating substrate containing glass epoxy, polyimide, polyester, ceramic, epoxy, bismaleimide triazine or the like as a main component. A circuit board on which wiring (wiring pattern) is formed by etching away the portion, a circuit board on which wiring (wiring pattern) is formed on the surface of the insulating substrate by metal plating or the like, and a conductive substance on the surface of the insulating substrate A circuit board on which wiring (wiring pattern) is formed by printing can be used.

  As the material of the wiring 8 and the connection part 4 that does not form a metal bond, gold, silver, copper, tin, nickel, or the like is used as a main component, and it may be composed of only a single component. You may be comprised from. Moreover, you may form so that the structure where these metals were laminated | stacked may be made | formed. From the viewpoint of cost, copper is preferable. From the viewpoint of connection reliability, gold is preferable.

  As the material of the connection part 5 forming the metal bond, solder (the main component is, for example, tin-silver, tin-lead, tin-bismuth, tin-copper) is used, and is composed of only a single component. It may be composed of a plurality of components.

  A semiconductor device (package) as shown in FIG. 1 or FIG. 2 is stacked, and 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 may be used for electrical connection. Copper and solder are preferable because they are inexpensive. For example, as seen in the TSV technology, an adhesive layer may be flip-chip connected or stacked between semiconductor chips to form a hole penetrating the semiconductor chip and connected to the electrode on the pattern surface.

  FIG. 3 is a schematic cross-sectional view showing another embodiment of the semiconductor device (semiconductor chip laminated type (TSV)). In the semiconductor device shown in FIG. 3A, the wiring 8 formed on the substrate 3 is connected to the connection portions 4 and 5 of the semiconductor chip 2, so that the semiconductor chip 2 and the substrate 3 are flip-chip connected. Yes. A film-like semiconductor adhesive 1 is interposed between the semiconductor chip 2 and the substrate 3. The semiconductor chip 2 is repeatedly laminated by the configuration of the wiring 8, the connecting portions 4 and 5, and the adhesive layer 1 on the surface of the semiconductor chip 2 opposite to the substrate 3. The wirings 8 on the pattern surface on the front and back sides of the semiconductor chip 2 are connected to each other by through electrodes 9 filled in holes that penetrate the inside of the semiconductor chip body 2. As a material of the through electrode 9, copper, aluminum, or the like can be used.

  With such TSV technology, a signal can be obtained from the back surface of a semiconductor chip that is not normally used. Furthermore, since the through electrode 9 is vertically passed through the semiconductor chip 2, the distance between the semiconductor chips 2 facing each other and between the semiconductor chip 2 and the substrate 3 can be shortened and flexible connection is possible. The adhesive layer according to the present embodiment can be applied as a sealing material between the semiconductor chips 2 facing each other and between the semiconductor chip 2 and the substrate 3 in such a TSV technology.

  In a bump forming method with a high degree of freedom such as area bump chip technology, a semiconductor chip can be directly mounted on a mother board without using an interposer. The adhesive layer according to this embodiment can also be applied when such a semiconductor chip is directly mounted on a mother board. Note that the adhesive layer according to the present embodiment can also be applied when sealing a gap between substrates when two printed circuit boards are stacked.

  FIG. 3B shows that the wiring 8 formed on the interposer 10 is connected to the connection portions 4 and 5 of the semiconductor chip 2 so that the semiconductor chip 2 and the substrate 3 are flip-chip connected. Except for this, it is the same as FIG.

  4 and 5 are schematic cross-sectional views showing other embodiments of the semiconductor device. The semiconductor device shown in FIG. 4 is the same as the semiconductor device shown in FIG. 2A except that a plurality of semiconductor chips 2 are flip-chip connected to the substrate 3 by connecting portions 4 and 5 and wirings 8. The semiconductor device shown in FIG. 5 is the same as the semiconductor device shown in FIG. 2B except that a plurality of semiconductor chips 2 are flip-chip connected to the interposer 10 by connecting portions 4 and 5 and wirings 8. .

  The semiconductor device is connected, for example, between the above-described bump and wiring. In this case, it is only necessary that the metal of either one of the connecting portions is equal to or higher than the melting point in the crimping step described later.

<Method for Manufacturing Semiconductor Device>
The semiconductor device manufacturing method of the first embodiment includes a semiconductor chip having a connection portion and a printed circuit board having a connection portion, and each connection portion is electrically connected to each other via a connection bump, Or a method of manufacturing a semiconductor device comprising a plurality of semiconductor chips each having a connection portion, wherein each connection portion is electrically connected to each other via a connection bump, wherein the connection portion is made of metal, and the semiconductor chip And the wiring circuit board or the semiconductor chips, with the film-like semiconductor adhesive interposed therebetween, and the connection portions are electrically connected by metal bonding. In this method, the semiconductor device is continuously manufactured by setting the thickness of the film-like semiconductor adhesive to T (μm) satisfying the following conditions 1 and 2.
Condition 1: T = X {α + (0.5β)}
Condition 2: 1.06 ≦ X ≦ 1.36
α: length of the portion where the metal chip is not formed in the connection portion of the semiconductor chip (μm)
β: length of the portion where the metal bond is formed in the connection portion of the semiconductor chip (μm)

  Thereby, for example, the semiconductor device shown in FIG. 1A or 2A can be obtained. Hereinafter, each process will be described with reference to FIG. 2A and FIG.

  First, a film-like adhesive for semiconductor (hereinafter sometimes referred to as “film-like adhesive”) is stuck on the substrate 3. The film adhesive can be applied by a hot press, roll lamination, vacuum lamination, or the like. The film adhesive may be affixed to the semiconductor chip 2, and after the film adhesive is affixed to the semiconductor wafer, the film adhesive is diced and separated into the semiconductor chips 2, thereby the semiconductor having the film adhesive affixed thereto. Chip 2 may be fabricated.

The thickness T of the film adhesive at this time is set so as to satisfy the following conditions 1 and 2.
Condition 1: T = X {α + (0.5β)}
Condition 2: 1.06 ≦ X ≦ 1.36
Here, α and β will be described with reference to FIG. FIG. 6 is a schematic cross-sectional view of the semiconductor chip 2, where 6 is the length of the connection portion 4 that does not form a metal bond, and α is the length 7 of the connection portion 5 that forms a metal bond.

  When the thickness of the film adhesive is 1.06> X, since the film adhesive is thin, the resin does not flow sufficiently and voids are likely to occur. On the other hand, when X> 1.36, the amount of fillet increases because the film adhesive is thick.

  The supply area of the film adhesive is preferably the same as that of the semiconductor chip 2. The greater the supply area, the greater the fillet width.

  After the semiconductor chip is picked up by a crimping tool, the connection parts 4 and 5 of the semiconductor chip 2 and the wiring 8 on the substrate are aligned so as to face each other. The semiconductor chip 2 and the substrate 8 are pressed while heating at a temperature equal to or higher than the melting point of the metal of the connection part 5 of the semiconductor chip (when solder is used for the connection part 5, it is preferable that the solder part takes 230 ° C. or more). While the chip and the substrate are connected, the gap between the semiconductor chips is sealed and filled with a film adhesive.

  The connection load depends on the number of bumps, but is set in consideration of absorption of bump height variations and control of the amount of bump deformation. When crimping, voids are eliminated, and the connection portion 5 of the semiconductor chip 2 and the wiring on the substrate 3 are in contact with each other. The larger the load, the easier it is to eliminate voids, and the metal at the connection and the connection bumps are more likely to come into contact. For example, 0.009N to 0.2N per pin (one bump) of the semiconductor chip 2 is preferable.

  The connection time is preferably as short as possible from the viewpoint of improving productivity, and the time is sufficient to melt the connection portion 5 (solder bump), remove the oxide film and impurities on the surface, and form a metal bond at the connection portion. can do. In addition, the connection in a short time means that the time which takes 230 degreeC or more will be 5 second or less if the connection part 5 is a solder bump during connection formation time (crimping time). The connection time is preferably 4 seconds or less, more preferably 3 seconds or less. The shorter the connection time, the higher the productivity.

  At this time, the connection process may be divided into two processes, a temporary pressure bonding and a main pressure bonding. For example, provisional pressure bonding is performed at a temperature equal to or lower than the melting point of the metal of the connection portion 5 of the semiconductor chip 2, and then heating is performed so that a temperature equal to or higher than the melting point of the metal of the connection portion 5 is applied. A semiconductor device may be manufactured by forming a metal bond.

  At the temperature at which the crimping tool is heated for connection, the minimum melt viscosity of the film adhesive is preferably 5000 Pa · s or less. Here, the “melt viscosity” is a rheometer (manufactured by Anton Paar Japan Co., Ltd., MCR301) under the conditions of a sample thickness: 400 μm, a heating rate of 10 ° C./min, and a frequency: 1 Hz. It refers to melt viscosity when measured using a disposable plate (diameter 8 mm) and a disposable sample dish).

  When the minimum melt viscosity of the film adhesive is 5000 Pa · s or less, the resin flows and the generation of voids is easily suppressed. However, if the viscosity is too low, the resin creeps up the side of the chip and adheres to the crimping tool, which may reduce productivity. The minimum melt viscosity of the film adhesive is preferably 1000 Pa · s or more.

  As a pressing device for pressure bonding, a flip chip bonder, a pressure oven, or the like can be used.

  In the crimping, a plurality of chips may be crimped. For example, in gang bonding in which a plurality of chips are bonded in a planar manner, a plurality of semiconductor chips may be temporarily bonded to a wafer or a map substrate one by one, and then a plurality of chips may be bonded together in a batch.

  In stack pressure bonding, which is often seen in a TSV structure package, a plurality of chips are three-dimensionally pressure bonded. In this case as well, a plurality of semiconductor chips may be stacked one by one and temporarily bonded, and then the plurality of chips may be collectively bonded together.

<Thermosetting resin composition>
The adhesive layer is preferably a layer formed of a thermosetting resin composition containing a compound having a weight average molecular weight of 10,000 or less and a curing agent thereof and having a minimum melt viscosity of 5000 Pa · s or less.

((A) thermosetting resin)
A thermosetting resin is a compound that can form a crosslinked structure by heating. The thermosetting resin has a molecular weight of 10,000 or less. Since a component having a low molecular weight decomposes during heating and causes voids, from the viewpoint of heat resistance, the thermosetting resin is preferably a compound that reacts with a curing agent to form a crosslinked structure. As a thermosetting resin, an acrylic resin and an epoxy resin are mentioned, for example.

(A1) Acrylic resin The acrylic resin is not particularly limited as long as it is a compound having one or more (meth) acryloyl groups in the molecule. Examples of the acrylic resin include a skeleton derived from a compound selected from bisphenol A, bisphenol F, naphthalene, phenol novolak, cresol novolak, phenol aralkyl, biphenyl, triphenylmethane, dicyclopentadiene, fluorene, adamantane, and isocyanuric acid. (Meth) acrylate and various polyfunctional (meth) acrylic compounds are mentioned. Among them, from the viewpoint of heat resistance, (meth) acrylate having a skeleton derived from a compound selected from bisphenol A, bisphenol F, naphthalene, fluorene, adamantane and isocyanuric acid is preferable. An acrylic resin can be used individually by 1 type or in combination of 2 or more types.

  10-50 mass parts is preferable with respect to 100 mass parts of whole quantity of a thermosetting resin composition, and, as for content of an acrylic resin, 15-40 mass parts is more preferable. When the content of the acrylic resin is less than 10 parts by mass, there are few curing components, so that it is difficult to sufficiently control the flow of the resin even after curing. When the content of the acrylic resin exceeds 50 parts by mass, the cured product tends to be too hard and the warpage of the package tends to increase.

  The acrylic resin is preferably solid at room temperature (25 ° C.). The solid is less likely to generate voids than the liquid, and the thermosetting resin composition before curing (B stage) has a lower viscosity (tack) and is excellent in handleability. Examples of the acrylic resin that is solid at room temperature (25 ° C.) include (meth) acrylates having a skeleton derived from a compound selected from bisphenol A, fluorene, adamantane, and isocyanuric acid.

  The number of functional groups of the (meth) acryloyl group in the acrylic resin is preferably 3 or less. If the number of functional groups is 4 or more, curing in a short time does not proceed sufficiently because the number of functional groups is large, and the curing reaction rate decreases (the curing network proceeds rapidly and unreacted groups remain). is there.

(A2) Epoxy resin The epoxy resin is not particularly limited as long as it is a compound having two or more epoxy groups in the molecule. Examples of the epoxy resin include bisphenol A type, bisphenol F type, naphthalene type, phenol novolac type, cresol novolac type, phenol aralkyl type, biphenyl type, triphenylmethane type and dicyclopentadiene type epoxy resin, and various polyfunctional epoxies. Resin. Among these, bisphenol F type and triphenylmethane type epoxy resins are preferable from the viewpoint of fast curability and heat resistance. An epoxy resin can be used individually by 1 type or in combination of 2 or more types.

  As for content of an epoxy resin, 10-50 mass parts is preferable with respect to 100 mass parts of whole quantity of a thermosetting resin composition. When the content of the epoxy resin is less than 10 parts by mass, there are few curing components, so that it is difficult to sufficiently control the flow of the resin even after curing. When content of an epoxy resin exceeds 50 mass parts, there exists a tendency for hardened | cured material to become hard too much and the curvature of a package will become large.

((B) curing agent)
The curing agent is not particularly limited as long as it is a compound that reacts with the thermosetting resin to form a crosslinked structure with the thermosetting resin. Examples of the curing agent include phenol resin curing agents, acid anhydride curing agents, amine curing agents, imidazole curing agents, phosphine curing agents, azo compounds, and organic peroxides. The curing system is preferably a radical polymerization system. A hardening | curing agent can be used individually by 1 type or in combination of 2 or more types.

  The combination of the thermosetting resin and the curing agent is not particularly limited as long as curing proceeds. The curing agent combined with the acrylic resin is preferably an organic peroxide from the viewpoints of handleability and storage stability. As a curing agent combined with an epoxy resin, a phenol resin curing agent and an imidazole curing agent, an acid anhydride curing agent and an imidazole curing agent, and an amine curing agent from the viewpoint of excellent handleability, storage stability, and curability. And an imidazole curing agent and an imidazole curing agent alone are preferred. Among them, it is more preferable to use an imidazole curing agent excellent in rapid curability alone because the productivity improves when cured in a short time. When cured in a short time, the amount of volatile components such as low molecular components can be reduced, so that the generation of voids can be further suppressed.

(B1) Phenolic resin-based curing agent 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 of the phenol resin-based curing agent include phenol novolak, cresol novolak, phenol aralkyl resin, cresol naphthol formaldehyde polycondensate, triphenylmethane type polyfunctional phenol and various polyfunctional phenol resins. These can be used individually by 1 type or in combination of 2 or more types.

  The equivalent ratio of the phenol resin-based curing agent to the epoxy resin (phenolic hydroxyl group / epoxy group, molar ratio) is preferably 0.3 to 1.5 from the viewpoint of excellent curability, adhesiveness, and storage stability. 4-1.0 is more preferable and 0.5-1.0 is still more preferable. When this equivalent ratio is 0.3 or more, the curability tends to be improved and the adhesive force tends to be improved, and when it is 1.5 or less, an unreacted phenolic hydroxyl group does not remain excessively, The water absorption rate is kept low, and the insulation reliability tends to improve.

(B2) Acid anhydride curing agent Examples of acid anhydride curing agents include methylcyclohexanetetracarboxylic dianhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic dianhydride, and ethylene glycol bis. Anhydro trimellitate is mentioned. These can be used individually by 1 type or in combination of 2 or more types.

  The equivalent ratio of the acid anhydride curing agent to the epoxy resin (acid anhydride group / epoxy group, molar ratio) is preferably 0.3 to 1.5 from the viewpoint of excellent curability, adhesiveness, and storage stability. 0.4-1.0 is more preferable and 0.5-1.0 is still more preferable. When the equivalent ratio is 0.3 or more, the curability is improved and the adhesive force tends to be improved. When the equivalent ratio is 1.5 or less, an unreacted acid anhydride does not remain excessively, The water absorption rate is kept low, and the insulation reliability tends to improve.

(B3) Amine-based curing agent Examples of the amine-based curing agent include dicyandiamide and dodecanediamine. These can be used individually by 1 type or in combination of 2 or more types.

  The equivalent ratio of the amine curing agent to the epoxy resin (amine / epoxy group, molar ratio) is preferably 0.3 to 1.5, and preferably 0.4 to 1 from the viewpoint of excellent curability, adhesiveness, and storage stability. 0.0 is more preferable, and 0.5 to 1.0 is still more preferable. If the equivalent ratio is 0.3 or more, the curability tends to be improved and the adhesive strength tends to be improved. If the equivalent ratio is 1.5 or less, an unreacted amine does not remain excessively and insulation reliability is improved. Tend to improve.

(B4) Imidazole-based curing agent 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'-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, Examples include 5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and adducts of epoxy resins and imidazoles. Among these, 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 adducts, 2-phenylimidazole isocyanuric acid adducts, 2-phenyl-4,5-dihydroxymethylimidazole and 2-phenyl 4- methyl-5-hydroxymethylimidazole is preferred. These can be used individually by 1 type or in combination of 2 or more types. Moreover, you may use these as a latent hardening | curing agent which encapsulated these.

  0.1-20 mass parts is preferable with respect to 100 mass parts of epoxy resins, and, as for content of an imidazole type hardening | curing agent, 0.1-10 mass parts is more preferable. If this content is 0.1 parts by mass or more, curability tends to be improved, and if it is 20 parts by mass or less, the thermosetting resin composition may be cured before metal bonding is formed. There is no tendency for poor connection to occur.

(B5) Phosphine curing agent Examples of the phosphine curing agent include triphenylphosphine, tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium tetra (4-methylphenyl) borate and tetraphenylphosphonium (4-fluorophenyl) borate. Can be mentioned. These can be used individually by 1 type or in combination of 2 or more types.

  0.1-10 mass parts is preferable with respect to 100 mass parts of epoxy resins, and, as for content of a phosphine type hardening | curing agent, 0.1-5 mass parts is more preferable. When this content is 0.1 parts by mass or more, curability tends to be improved, and when it is 10 parts by mass or less, the thermosetting resin composition may be cured before metal bonding is formed. There is no tendency for poor connection to occur.

(B6) Azo compound An azo compound may be used alone or in combination of two or more.

  0.5-10 mass parts is preferable with respect to 100 mass parts of acrylic resins, and, as for content of an azo compound, 1-5 mass parts is more preferable. When the content is less than 0.5 parts by mass, the curing may not proceed sufficiently. When the content exceeds 10 parts by mass, the curing proceeds rapidly and the number of reaction points increases, so the molecular chain is short. Or unreacted groups remain, and the reliability tends to decrease.

(B7) Organic peroxide Examples of the organic peroxide include ketone peroxide, peroxyketal, hydroperoxide, dialkyl peroxide, diacyl peroxide, peroxydicarbonate, and peroxyester. As the organic peroxide, hydroperoxide, dialkyl peroxide and peroxyester are preferable from the viewpoint of storage stability. Further, as the organic peroxide, hydroperoxide and dialkyl peroxide are preferable from the viewpoint of heat resistance. These can be used individually by 1 type or in combination of 2 or more types.

  0.5-10 mass parts is preferable with respect to 100 mass parts of acrylic resins, and, as for content of an organic peroxide, 1-5 mass parts is more preferable. When the content is less than 0.5 parts by mass, the curing may not proceed sufficiently. When the content exceeds 10 parts by mass, the curing proceeds rapidly and the number of reaction points increases, so the molecular chain is short. Or unreacted groups remain, and the reliability tends to decrease.

((C) high molecular weight component)
The thermosetting resin composition according to this embodiment may further contain a high molecular weight component having a weight average molecular weight of 10,000 or more. The weight average molecular weight or molecular weight of components other than the high molecular weight component, such as a thermosetting resin and a curing agent, is usually less than 10,000. Examples of the high molecular weight component include epoxy resin, phenoxy resin, polyimide resin, polyamide resin, polycarbodiimide resin, cyanate ester resin, acrylic resin, polyester resin, polyethylene resin, polyethersulfone resin, polyetherimide resin, and polyvinyl acetal resin. , Urethane resin and acrylic rubber. Among them, from the viewpoint of excellent heat resistance and film formability, epoxy resin, phenoxy resin, polyimide resin, acrylic resin, acrylic rubber, cyanate ester resin and polycarbodiimide resin are preferable, and from the viewpoint of further excellent heat resistance and film formability. Epoxy resin, phenoxy resin, polyimide resin, acrylic resin and acrylic rubber are more preferable. These high molecular weight components can be used singly or in combination of two or more.

  The mass ratio between the high molecular weight component and the acrylic resin is not particularly limited, but the acrylic resin content is preferably 0.01 to 10 parts by mass, and 0.05 to 5 parts by mass with respect to 1 part by mass of the high molecular weight component. Is more preferable, and 0.1-5 mass parts is still more preferable. When this mass ratio is less than 0.01 parts by mass, the curability may be reduced and the adhesive strength may be reduced. When the mass ratio is more than 10 parts by mass, the film formability may be reduced.

  The mass ratio of the high molecular weight component and the epoxy resin is not particularly limited, but the content of the epoxy resin is preferably 0.01 to 5 parts by mass, and 0.05 to 4 parts by mass with respect to 1 part by mass of the high molecular weight component. Is more preferable, and 0.1-3 mass parts is still more preferable. When this mass ratio is less than 0.01 parts by mass, the curability may be reduced and the adhesive strength may be reduced. When it is greater than 5 parts by mass, the film formability and the film formability may be reduced.

  The glass transition temperature (Tg) of the high molecular weight component is preferably 120 ° C. or less, more preferably 100 ° C. or less, and still more preferably 85 ° C. or less, from the viewpoint of excellent stickability of the thermosetting resin composition to the substrate and chip. . When Tg exceeds 120 ° C., it is difficult to embed irregularities such as bumps formed on the semiconductor chip, electrodes formed on the substrate or wiring patterns with the thermosetting resin composition, and bubbles remain and voids are formed. It tends to occur. In addition, Tg is Tg when measured using DSC (DSC-7 type manufactured by Perkin Elmer Co., Ltd.) under the conditions of a sample amount of 10 mg, a heating rate of 10 ° C./min, and a measurement atmosphere: air.

  The weight average molecular weight of the high molecular weight component is 10,000 or more in terms of polystyrene, but preferably 30000 or more, more preferably 40000 or more, and even more preferably 50000 or more in order to exhibit good film formability alone. If the weight average molecular weight is less than 10,000, the film formability tends to decrease. In addition, in this specification, a weight average molecular weight means the weight average molecular weight when measured in polystyrene conversion using a high performance liquid chromatography (Shimadzu Corporation C-R4A).

((D) filler)
The thermosetting resin composition according to the present embodiment controls the viscosity and physical properties of the cured product, and further generates voids and absorbs moisture when the semiconductor chips are connected to each other or between the semiconductor chip and the substrate. For suppression, a filler may be further contained. Examples of the filler include an inorganic filler and a resin filler.
Examples of the inorganic filler include insulating inorganic fillers such as glass, silica, alumina, titanium oxide, carbon black, mica, and boron nitride. Among these, silica, alumina, titanium oxide and boron nitride are preferable, and silica, alumina and boron nitride are more preferable. The insulating inorganic filler may be a whisker. Examples of whiskers include aluminum borate, aluminum titanate, zinc oxide, calcium silicate, magnesium sulfate, and boron nitride.
Examples of the resin filler include polyurethane, polyimide, methyl methacrylate resin, and methyl methacrylate-butadiene-styrene copolymer resin (MBS). A filler can be used individually by 1 type or in combination of 2 or more types. The shape, particle size, and content of the filler are not particularly limited.

  From the viewpoint of excellent insulation reliability, the filler is preferably insulating. It is preferable that the thermosetting resin composition according to the present embodiment does not contain a conductive metal filler such as a silver filler or a solder filler.

  The physical properties of the filler may be appropriately adjusted by surface treatment. The filler is preferably a surface-treated filler from the viewpoint of improving dispersibility and adhesive strength. Examples of the surface treatment agent include glycidyl (epoxy), amine, phenyl, phenylamino, (meth) acrylic, and vinyl compounds.

  As the surface treatment, a silane treatment with a silane compound such as an epoxy silane, amino silane, or acrylic silane is preferable because of the ease of surface treatment. As the surface treatment agent, glycidyl, phenylamino, acrylic and methacrylic compounds are preferred from the viewpoint of excellent dispersibility, fluidity and adhesive strength. Of these, phenyl, acrylic and methacrylic compounds are more preferred from the viewpoint of storage stability.

  The average particle size of the filler is preferably 1.5 μm or less from the viewpoint of preventing biting during flip chip connection, and more preferably 1.0 μm or less from the viewpoint of excellent visibility (transparency). The particle diameter of the filler means the major axis diameter of the particles.

  Since the resin filler can impart flexibility at a high temperature such as 260 ° C. as compared with the inorganic filler, it is suitable for improving the reflow resistance. Moreover, since flexibility provision is possible, it is effective also in film-formability improvement.

  The content of the filler is preferably 30 to 90% by mass, more preferably 40 to 80% by mass, based on the entire solid content of the thermosetting resin composition. When the content is less than 30% by mass, heat dissipation is low, and there is a tendency that voids are generated and the moisture absorption rate is increased. When this content exceeds 90% by mass, the viscosity becomes high, the fluidity of the thermosetting resin composition is lowered and the filler is trapped (trapping), and the connection reliability tends to be lowered. is there.

((E) Flux agent)
The thermosetting resin composition according to the present embodiment may further contain a flux agent (that is, a flux activator exhibiting flux activity (activity for removing oxides and impurities)). Examples of the fluxing agent include nitrogen-containing compounds having a lone pair such as imidazoles and amines, carboxylic acids, phenols, and alcohols. Compared with alcohol and the like, organic acids (such as carboxylic acids such as 2-methylglutaric acid) strongly express the flux activity and improve connectivity.

  The content of the fluxing agent is preferably 0.005 to 10.0% by mass based on the entire solid content of the thermosetting resin composition.

  The thermosetting resin composition according to this embodiment may further contain additives such as an ion trapper, an antioxidant, a silane coupling agent, a titanium coupling agent, and a leveling agent. An additive can be used individually by 1 type or in combination of 2 or more types. What is necessary is just to adjust suitably content of an additive so that the effect of each additive may express.

The curing reaction rate when the thermosetting resin composition according to this embodiment is held at 200 ° C. for 5 seconds is preferably 80% or more, and more preferably 90% or more. When the curing reaction rate at 200 ° C. (below the solder melting temperature) / 5 seconds is lower than 80%, the solder scatters and flows at the time of connection (above the solder melting temperature), and the connection reliability and the insulation reliability are likely to deteriorate. The curing reaction rate was measured by putting a sample amount (film adhesive) 10 mg in an aluminum pan, and then using DSC (DSC-7 model manufactured by PerkinElmer Co., Ltd.) at a temperature rising rate of 20 ° C./min and a temperature of 30 to 300 ° C. Measured in range. ΔH (J / g) when measuring an untreated sample is “ΔH1”, and ΔH (J / g) when measuring a sample heat-treated on a hot plate at 200 ° C. for 5 seconds is “ΔH2”. The curing reaction rate was calculated by the following formula.
(ΔH1−ΔH2) / ΔH1 × 100 = curing reaction rate (%)
When the curing system of the thermosetting resin composition is radical polymerization, when the thermosetting resin composition contains an anion polymerizable epoxy resin (particularly, an epoxy resin having a weight average molecular weight of less than 10,000), the curing reaction rate is 80. % May be difficult to adjust. When the thermosetting resin composition contains an acrylic resin and an epoxy resin, the content of the epoxy resin is preferably 20 parts by mass or less with respect to 80 parts by mass of the acrylic resin.

  The thermosetting resin composition according to the present embodiment can be used for pressure bonding at a high temperature of 200 ° C. or higher. Further, in a flip chip package in which a metal such as solder is melted to form a connection, further excellent curability is exhibited.

  The adhesive layer according to the present embodiment is preferably a layer formed by an adhesive film prepared in advance from the viewpoint of improving productivity. The example of the production method of an adhesive film is shown below.

  First, if necessary, a resin varnish is prepared by adding a thermosetting resin, a curing agent, a high molecular weight component, a filler, other additives, etc. in an organic solvent and then dissolving or dispersing by stirring, kneading, etc. To do. Next, after applying a resin varnish using a knife coater, roll coater, applicator, die coater, comma coater, etc. on the base film subjected to the release treatment, the organic solvent is reduced by heating, and the base film An adhesive film is formed thereon. In addition, before reducing the organic solvent by heating, an adhesive film may be formed on the wafer by a method of drying the solvent after spin-coating a resin varnish on the wafer or the like to form a film.

  The base film is not particularly limited as long as it has heat resistance capable of withstanding the heating conditions when the organic solvent is volatilized, and a polyethylene film, a polypropylene film, a polyethylene terephthalate film, a polyimide film, a polyetherimide film, a poly Examples include ether naphthalate film and methylpentene film. The base film is not limited to a single layer composed of one of these films, and may be a multilayer film composed of two or more films.

  Specifically, the conditions for volatilizing the organic solvent from the resin varnish after coating are preferably performed at 50 to 200 ° C. for 0.1 to 90 minutes. As long as there is no effect on the void and viscosity adjustment after mounting, it is preferable that the organic solvent is volatilized to 1.5% by mass or less.

<Production of film adhesive>
The compounds used are shown below.
(I) High molecular weight component having a weight average molecular weight exceeding 10,000 Acrylic rubber (manufactured by Hitachi Chemical Co., Ltd., KH-C865, Tg: 0 to 12 ° C., Mw (weight average molecular weight): 450,000 to 650000)
Phenoxy resin (manufactured by Toto Kasei Co., Ltd., ZX-1356-2, Tg: about 71 ° C., Mw: about 63000)
(Ii) Compound having a weight average molecular weight of 10,000 or less: (meth) acryl compound fluorene skeleton acrylate (manufactured by Osaka Gas Chemical Co., Ltd., EA0200, bifunctional group)
(Iii) Compound having a weight average molecular weight of 10,000 or less: epoxy resin, triphenolmethane skeleton-containing polyfunctional solid epoxy (manufactured by Japan Epoxy Resin Co., Ltd., EP 1032H60)
Bisphenol F type liquid epoxy (Japan Epoxy Resin Co., Ltd. YL983U)
(Iv) Curing agent Dicumyl peroxide (manufactured by NOF Corporation, Park Mill D)
2,4-diamine-6 [2′-methylimidazolyl- (1 ′)-ethyl-s-triazine isocyanuric acid adduct (manufactured by Shikoku Kasei Kogyo Co., Ltd., 2MAOK-PW))
(V) Inorganic filler Silica filler (manufactured by Admatechs, SE2050, average particle size 0.5 μm)
Epoxysilane surface-treated silica filler (manufactured by Admatechs, SE2050SEJ, average particle size 0.5 μm)
Methacrylic surface-treated nanosilica filler (manufactured by Admatechs Co., Ltd., YA050C-SM, hereinafter referred to as SM nanosilica, average particle size of about 50 nm)
(Vi) Resin filler Organic filler (Rohm and Haas Japan Co., Ltd., EXL-2655: Core-shell type organic fine particles)
(Vii) Flux agent 2-Methylglutaric acid (manufactured by Aldrich, melting point: about 77 ° C.)

Production method of film adhesive The non-volatile content is 60% by mass (the liquid component is 40% by mass of the solvent) with respect to the (meth) acrylic compound or epoxy resin, inorganic filler, resin filler and flux agent shown in Table 1. The organic solvent (methyl ethyl ketone) was added so that all the components constituting the adhesive such as solid component and filler were 60% by mass). Thereafter, beads having a diameter of 1.0 mm and a diameter of 2.0 mm were added in the same weight as the solid content, and the mixture was stirred for 30 minutes with a bead mill (manufactured by Fritsch Japan Co., Ltd., planetary pulverizer P-7). Thereafter, the high molecular weight component was added, and the mixture was again stirred with a bead mill for 30 minutes. After stirring, the curing agent was added and stirred, and then the beads used were removed by filtration to obtain two types of resin varnishes.

  Each resin varnish produced was coated on a base film whose surface was release-treated with a small precision coating device (manufactured by Yasui Seiki Co., Ltd.), and the coated resin varnish was cleaned in a clean oven (ESPEC Corporation) Two types of film adhesives A and B were obtained by drying (70 degreeC, 10min) by company manufacture.

  About the obtained adhesive film, the minimum melt viscosity was measured by the following method.

[Measurement of melt viscosity]
Using a rheometer (manufactured by Anton Paar Japan Co., Ltd., MCR301) under the conditions of sample thickness: 400 μm, heating rate 10 ° C./min, frequency: 1 Hz, measuring jig (disposable plate (diameter 8 mm) and disposable sample dish) ) Was used to measure the melt viscosity at the pressure head temperature (° C.) during the temporary pressure bonding step shown in Table 2. The results are shown in Table 2.

<Manufacture of semiconductor devices>
(Examples 1 and 2 and Comparative Examples 1 and 2)
A pressing member (FCB3, manufactured by Panasonic Corporation) having an opposing stage and a pressure bonding head was prepared, and a semiconductor device was manufactured by the following procedure.
The film-like adhesive A of the produced production example was attached to a semiconductor wafer with solder bumps and separated into pieces by dicing. Table 2 shows the film thickness of the pasted film adhesive. Next, the separated semiconductor chip with an adhesive film (chip size: 7.3 mm long, 7.3 mm wide, 0.15 mm thick, metal at the connection part: copper pillar + solder, copper pillar height 15 μm, solder height 10 μm, 1048 bumps, 80 μm pitch, product name: WALTS-TEG CC80, manufactured by WALTS, and semiconductor chip on the stage of the pressing member (chip size: 10 mm long, 10 mm wide, 0.1 mm thick, connection Part metal: Au, product name: WALTS-TEG IP80, manufactured by WALTS) were aligned so that the respective connection parts face each other. Thereafter, the semiconductor chip was pressed between the crimping head and the stage and pressed and heated so that the connecting portions were in contact with each other, and the semiconductor chips were electrically connected. The maximum temperature reached by the pressure-bonding head at the time of pressure-bonding was 260 ° C., and the stage temperature was 80 ° C.

(Examples 3 and 4 and Comparative Examples 3 and 4)
Except having changed into the film adhesive B shown in Table 1 in the kind of adhesive film, it was the same as Example 1, 2 and Comparative Examples 1,2.

<Evaluation>
About the obtained semiconductor device, void evaluation and fillet evaluation were performed.

[Void evaluation]
An external image of the obtained semiconductor device is taken with an ultrasonic diagnostic imaging apparatus (Insight-300, manufactured by Insight), and an image of the adhesive layer on the semiconductor chip is captured with a scanner GT-9300UF (manufactured by Seiko Epson Corporation). Using the image processing software Adobe Photoshop (registered trademark), the void portion was identified by color tone correction and two-gradation, and the ratio of the void portion was calculated by the histogram. The area of the adhesive layer on the semiconductor chip was 100%. A case where the void exclusive area was 5% or less was evaluated as “◯”, and a case where it exceeded 5% was determined as “x”. The results are shown in Table 2.

[Fillet evaluation]
From the upper side, the length of the fillet was measured using a microscope (VHX-5000), manufactured by Keyence Corporation. A fillet length of 100 μm or less was evaluated as “◯”, and 100 μm or more was evaluated as “x”. The results are shown in Table 2.

From the results of Table 2, according to the method according to the present embodiment, it is possible to obtain a semiconductor device that can sufficiently suppress the generation of voids and suppress the fillet. On the other hand, in Comparative Examples 1 and 3, the coefficient X relating to the thickness of the film adhesive was in the region of 1.06> X, and the film was too thin, so that the resin flow was insufficient and voids were generated. In Comparative Examples 2 and 4, the coefficient X related to the thickness of the film adhesive was in the region of X> 1.36, and the void evaluation was good, but the film was thick and the fillet was large.

1 ... Film-like semiconductor adhesive (adhesive layer)
2 ... Semiconductor chip 3 ... Substrate 4 ... Connection part (part not forming metal bond)
5 ... Connection part (part which forms a metal bond)
6: Length of connecting portion (portion where metal bond is not formed) 7: Length of connecting portion (portion where metal bond is formed) 8: Wiring 9 ... Through electrode 10 ... Interposer

Claims (4)

A semiconductor device including a semiconductor chip having a connection portion and a printed circuit board having a connection portion, each of the connection portions being electrically connected to each other, or a plurality of semiconductor chips having connection portions, each of the connections A method of manufacturing a semiconductor device in which parts are electrically connected to each other, wherein the connection part is made of metal,
The semiconductor chip and the printed circuit board, or the semiconductor chips, wherein the respective connecting portions are electrically connected by metal bonding in a state where a film-like semiconductor adhesive is interposed therebetween. A device manufacturing method comprising:
A method of manufacturing a semiconductor device, wherein a thickness T (μm) of the film-like semiconductor adhesive is T satisfying the following conditions 1 and 2.
Condition 1: T = X {α + (0.5β)}
Condition 2: 1.06 ≦ X ≦ 1.36
α: length of the portion where the metal chip is not formed in the connection portion of the semiconductor chip (μm)
β: length of the portion where the metal bond is formed in the connection portion of the semiconductor chip (μm)   2. The method for manufacturing a semiconductor device according to claim 1, wherein the film-like semiconductor adhesive contains a compound having a weight average molecular weight of 10,000 or less and a curing agent thereof, and has a minimum melt viscosity of 5000 Pa · s or less.   The method for manufacturing a semiconductor device according to claim 1, wherein the film-like semiconductor adhesive further contains a high molecular weight component having a weight average molecular weight exceeding 10,000.   The method for manufacturing a semiconductor device according to claim 3, wherein the high molecular weight component is a component having a weight average molecular weight of 30000 or more and a glass transition temperature of 100 ° C. or less.

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