JPWO2018225323A1 - Semiconductor film adhesive, method of manufacturing semiconductor device, and semiconductor device - Google Patents

Abstract

The film adhesive for semiconductors of the present invention includes a first adhesive layer and a second adhesive layer provided on the first adhesive layer, and has an elastic modulus at curing at 35 ° C. of 3.0 to It is 5.0 GPa.

Description

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

  Conventionally, in order to connect a semiconductor chip and a substrate, a wire bonding method using a thin metal wire such as a gold wire has been widely applied. On the other hand, in order to respond to demands for higher functionality, higher integration, higher speed, etc. for semiconductor devices, flip chips that directly connect the semiconductor chip and the substrate by forming conductive protrusions called bumps on the semiconductor chip or the substrate. The connection method (FC connection method) is spreading.

  For example, regarding connection between a semiconductor chip and a substrate, a COB (Chip On Board) type connection method which is frequently used in BGA (Ball Grid Array), CSP (Chip Size Package), and the like also corresponds to the FC connection method. The FC connection method is also widely used in a COC (Chip On Chip) type connection method in which a connection portion (for example, a bump and a wiring) is formed on a semiconductor chip and the semiconductor chips are connected to each other (for example, a COC (Chip On Chip) type connection method). And Patent Document 1).

  Further, in a package that is strongly required to be further miniaturized, thinned and highly functional, a chip stack type package, a POP (Package On Package), a TSV (Package On Package) in which chips are stacked using the above-described connection method to form a multi-stage. Through-silicon vias) have begun to spread widely. In such a stacking / multi-stage technique, since semiconductor chips and the like are arranged three-dimensionally, the size of the package can be reduced as compared with a technique of arranging two-dimensionally. In addition, since it is effective in improving the performance of semiconductors, reducing noise, reducing the mounting area, and saving power, it has attracted attention as a next-generation semiconductor wiring technology.

JP 2008-294382 A

  By the way, in the flip chip package, high functionality and miniaturization are rapidly progressing. As the number of bumps increases along with the advancement of functions and miniaturization, the pitch and the gap are becoming narrower. When the number of bumps is increased and the pitch and gap are reduced, trap voids involving the space around the bumps, and voids such as weld voids generated behind the bumps due to resin flow during pressure bonding often occur after mounting. is there.

  Further, in the flip chip package, from the viewpoint of improving the productivity, it is required to shorten the pressure bonding time at the time of assembling the flip chip package. In order to shorten the pressure bonding time, it is necessary to perform pressure bonding at a high temperature. However, such a high temperature pressure bonding makes it difficult for the film adhesive for semiconductors to be sufficiently cured during the pressure bonding, so that voids due to moisture and foaming components are generated. In addition, there is a case where minute voids due to the entrainment expand due to high temperature and many fatal voids are generated. When the flip-chip package is used for a long period of time, peeling may occur inside the package starting from these voids. When the peeling inside the package becomes large, stress is applied to the connecting portion and a crack occurs, so that the peeling inside the package leads to a poor connection of the package.

  Further, in the flip chip package, it is required to mount the flip chip package at a wafer level when assembling the flip chip package from the viewpoint of improving productivity. In this case, since a large number of packages are mounted on one bottom wafer, stress is applied to each package, and large warpage occurs in the bottom wafer. When the bottom wafer is warped, it is difficult to fix the bottom wafer to the suction table in the subsequent sealing step, and it becomes difficult to seal the package.

  For the above reasons, the film adhesive for semiconductors is required to have not only an improvement in connection reliability but also a performance capable of reducing voids and warpage.

  Accordingly, the present invention is directed to a semiconductor film capable of suppressing warpage of a bottom wafer even at a wafer-level mounting and obtaining excellent connection reliability without voids after mounting, even when a crimping time is shortened. An object of the present invention is to provide an adhesive in a shape. Another object of the present invention is to provide a semiconductor device using such a film adhesive for semiconductors and a method for manufacturing the same.

  The present inventors have studied by focusing on the elastic modulus of the film adhesive after curing in order to reduce the warpage of the single-layer film adhesive. As a result, in the case of a single-layered film adhesive, when the amount of the filler is increased to improve the elastic modulus, voids are likely to be generated. On the other hand, when the amount of the curing agent is increased to reduce the voids, the connection is increased. It has been clarified that the reliability is reduced, and it is difficult to achieve both connection reliability, reduction of voids and reduction of warpage. Therefore, as a result of further studies by the present inventors, the present inventors have found that a film-like adhesive is used for a first adhesive layer and a second adhesive layer provided on the first adhesive layer. By adjusting the elastic modulus after curing to a specific range on the basis of the film-form adhesive provided, it has been found that connection reliability, reduction of voids and reduction of warpage can both be achieved, and the present invention has been completed.

  One aspect of the present invention includes a first adhesive layer and a second adhesive layer provided on the first adhesive layer, and has an elastic modulus at 35 ° C. after curing of 3.0 to 5.0 GPa. The present invention relates to a film adhesive for a semiconductor.

  According to the film adhesive for semiconductors described above, it is possible to suppress the warpage of the bottom wafer even at the wafer level mounting and to obtain excellent connection reliability without voids after mounting even when the pressing time is shortened. Can be. Moreover, according to the film adhesive for semiconductors, since the pressing time can be shortened, the productivity can be improved. Further, according to the film adhesive for semiconductors, the flip chip package can be easily enhanced in function and highly integrated.

  One aspect of the present invention is a film adhesive for semiconductors containing a filler, comprising a first adhesive layer, a second adhesive layer provided on the first adhesive layer, the content of the filler Is 30 to 60% by mass based on the total mass of the film adhesive for semiconductors.

  According to the film adhesive for semiconductors described above, it is possible to suppress the warpage of the bottom wafer even at the wafer level mounting and to obtain excellent connection reliability without voids after mounting even when the pressing time is shortened. Can be. Moreover, according to the film adhesive for semiconductors, since the pressing time can be shortened, the productivity can be improved. Further, according to the film adhesive for semiconductors, the flip chip package can be easily enhanced in function and highly integrated.

  At least one of the first adhesive layer and the second adhesive layer may be a thermosetting adhesive layer, and both may be thermosetting adhesive layers. In this case, shrinkage under an environment such as a temperature cycle test can be reduced, and more excellent connection reliability is easily obtained.

  At least one of the first adhesive layer and the second adhesive layer may be a thermosetting adhesive layer containing a flux compound. In recent years, there has been a tendency to use solder, copper, or the like instead of gold or the like which is less likely to corrode as a metal of a connection portion for the purpose of cost reduction. Further, regarding the surface treatment of wirings and bumps, there is a tendency to use solder, copper or the like instead of gold or the like which is hardly corroded for the purpose of cost reduction. In particular, in flip-chip packages, since the cost has been reduced, there is a tendency to use a metal which is liable to be corroded and deteriorated in insulation properties, so that connection reliability (for example, insulation reliability) tends to be reduced. In addition, as described above, in order to suppress the generation of impurities, there is a case where an anti-oxidation film is formed by performing a process such as an OSP process. It may cause a decrease or the like. On the other hand, when at least one of the first adhesive layer and the second adhesive layer contains a flux compound, the oxide film and impurities at the connection portion can be removed, and a more excellent connection reliability tends to be obtained. is there.

［式（２）中、Ｒ^１及びＲ^２は、それぞれ独立して、水素原子又は電子供与性基を示し、ｎは０又は１以上の整数を示す。複数存在するＲ^２は互いに同一でも異なっていてもよい。］The flux compound may have a carboxyl group, may have two or more carboxyl groups, and may be a compound represented by the following formula (2). When such a flux compound is used, more excellent connection reliability is easily obtained.

[In the formula (2), R ¹ and R ² each independently represent a hydrogen atom or an electron donating group, and n represents 0 or an integer of 1 or more. A plurality of R ² may be the same or different from each other. ]

  The melting point of the flux compound may be 150 ° C. or less. In this case, the flux is melted before the adhesive is cured during thermocompression bonding, and the oxide film such as solder is reduced and removed, so that more excellent connection reliability is easily obtained.

  One of the first adhesive layer and the second adhesive layer may be a thermosetting adhesive layer containing no flux compound. In this case, since the adhesive layer containing no flux compound is hardly affected by the flux compound, the layer can exhibit a property of being quickly and sufficiently cured after the connecting portions are brought into contact with each other, and the pressure bonding can be performed at a high temperature. In addition, even in the case of performing in a short time, it is possible to obtain more excellent connection reliability (for example, insulation reliability).

  When one of the first adhesive layer and the second adhesive layer does not contain a flux compound, the layer not containing a flux compound may contain a radical polymerizable compound and a thermal radical generator. In this case, since the curing speed is extremely excellent, voids are unlikely to be generated even when the pressure bonding is performed at a high temperature for a short time, and more excellent connection reliability can be obtained.

  The thermal radical generator may be a peroxide. In this case, more excellent handleability and storage stability are obtained, so that more excellent connection reliability is easily obtained.

  The radical polymerizable compound may be a (meth) acrylic compound. In this case, more excellent connection reliability is easily obtained.

  The (meth) acrylic compound may have a fluorene-type skeleton. In this case, more excellent connection reliability is easily obtained.

  When one of the first adhesive layer and the second adhesive layer is a thermosetting adhesive layer containing no flux compound, the thermosetting adhesive layer containing no flux compound may contain an epoxy resin. . In this case, more excellent connection reliability and storage stability are easily obtained.

  The thermosetting adhesive layer containing no flux compound may further contain a latent curing agent. In this case, more excellent connection reliability is easily obtained.

  The latent curing agent may be an imidazole-based curing agent. In this case, a flux activity that suppresses the formation of an oxide film at the connection portion is obtained, so that more excellent connection reliability is easily obtained.

  One aspect of the present invention is a semiconductor device in which connection portions of a semiconductor chip and a printed circuit board are electrically connected to each other, or a semiconductor device in which connection portions of a plurality of semiconductor chips are electrically connected to each other. A method for manufacturing a semiconductor device, comprising a step of sealing at least a part of a connection portion using the film adhesive for semiconductor described above. According to this manufacturing method, even in the case of mounting at a wafer level, even if the warpage of the bottom wafer is suppressed and the crimping time is shortened, the semiconductor has excellent connection reliability (for example, insulation reliability) without voids after mounting. A device can be obtained. That is, according to the above manufacturing method, a semiconductor device having excellent connection reliability (for example, insulation reliability) can be manufactured in a short time.

  One aspect of the present invention is a semiconductor device in which connection portions of a semiconductor chip and a printed circuit board are electrically connected to each other, or a semiconductor device in which connection portions of a plurality of semiconductor chips are electrically connected to each other. The present invention relates to a semiconductor device in which at least a part of a connection portion is sealed with a cured product of the film adhesive for a semiconductor described above. In this semiconductor device, warpage and voids are reduced, and excellent continuous reliability (for example, insulation reliability) is exhibited.

  ADVANTAGE OF THE INVENTION According to this invention, even if it mounts at a wafer level and suppresses the warpage of a bottom wafer and shortens the pressure bonding time, a film for a semiconductor can obtain excellent connection reliability without voids after mounting. An adhesive can be provided. Further, according to the present invention, it is possible to provide a semiconductor device using such a film adhesive for a semiconductor and a method for manufacturing the same.

FIG. 1 is a schematic sectional view showing one embodiment of the semiconductor device of the present invention. FIG. 2 is a schematic sectional view showing another embodiment of the semiconductor device of the present invention. FIG. 3 is a schematic sectional view showing another embodiment of the semiconductor device of the present invention. FIG. 4 is a process sectional view schematically showing one embodiment of a method for manufacturing a semiconductor device of the present invention.

  In the present specification, “(meth) acrylate” means at least one of acrylate and methacrylate corresponding thereto. The same applies to other similar expressions such as “(meth) acryloyl” and “(meth) acrylic acid”. Further, the numerical range indicated by using “to” indicates a range including the numerical values described before and after “to” as the minimum value and the maximum value, respectively. In addition, the upper limit and lower limit individually described can be arbitrarily combined.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary.
In the drawings, the same or corresponding parts have the same reference characters allotted, and overlapping description will be omitted. Unless otherwise specified, the positional relationship such as up, down, left, and right is based on the positional relationship shown in the drawings. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

<Film adhesive for semiconductor>
The film adhesive for a semiconductor of the first embodiment includes a first adhesive layer and a second adhesive layer provided on the first adhesive layer, and has an elastic modulus at 35 ° C. after curing of 3. 0 to 5.0 GPa.

  The film adhesive for semiconductor of the second embodiment is a film adhesive for semiconductor containing a filler, a first adhesive layer, a second adhesive layer provided on the first adhesive layer The content of the filler is 30 to 60% by mass based on the total mass of the film adhesive for semiconductors.

  The film adhesive for semiconductors of the first embodiment and the second embodiment is, for example, a non-conductive adhesive (film-shaped non-conductive adhesive for semiconductor), and includes a semiconductor chip and a wiring circuit board. In a semiconductor device in which connection portions are electrically connected to each other, or in a semiconductor device in which connection portions of a plurality of semiconductor chips are electrically connected to each other, the semiconductor device is used to seal at least a part of the connection portion. Can be

  According to the semiconductor film adhesives of the first embodiment and the second embodiment, even when mounting at the wafer level, the warpage of the bottom wafer is suppressed, and the crimping time (for example, the bonding of the semiconductor chip and the wiring circuit board is performed) Therefore, even if the crimping time in the crimping step is shortened (for example, the crimping time is set to 5 seconds or less), excellent connection reliability can be obtained without voids after mounting.

  Hereinafter, first, the film adhesive for semiconductor of the first embodiment will be described in detail.

(First embodiment)
In the present embodiment, the first adhesive layer and the second adhesive layer are different layers, and are formed of different adhesive compositions. At least one of the first adhesive layer and the second adhesive layer may be, for example, a thermosetting adhesive layer formed of a thermosetting resin composition (an adhesive layer containing a thermosetting resin composition), The photocurable adhesive layer (adhesive layer containing the photocurable resin composition) formed of the photocurable resin composition may be used. From the viewpoint that shrinkage under an environment such as a temperature cycle test can be reduced and more excellent connection reliability is obtained, at least one of the first adhesive layer and the second adhesive layer is a thermosetting resin. The composition is preferably a thermosetting adhesive layer, and more preferably both are thermosetting adhesive layers.

  The first adhesive layer and the second adhesive layer may be adhesive layers containing a flux compound, or may be adhesive layers containing no flux compound. That is, the resin composition constituting the first adhesive layer and the second adhesive layer may be a resin composition containing a flux compound (hereinafter, referred to as a “flux-containing composition”), and contains a flux compound. Resin composition (hereinafter, referred to as “flux-free composition”).

  Generally, metal bonding is used to connect the connection portions from the viewpoint of ensuring sufficient connection reliability (for example, insulation reliability), and a main metal used for the connection portion (for example, a bump and a wiring) is used. Examples include solder, tin, gold, silver, copper, nickel and the like. Conductive materials containing these plural kinds of metals are also used. On the other hand, in the metal used for the connection portion, impurities are generated on the connection surface of the connection portion because the surface is oxidized to form an oxide film, and impurities such as oxides adhere to the surface. There are cases. If such impurities remain, the connection reliability (for example, insulation reliability) between the semiconductor chip and the substrate or between the two semiconductor chips decreases, and the merit of adopting the FC connection method described above is impaired. It is feared that it will. Therefore, as a method of suppressing the generation of these impurities, there is a method of coating a connection portion with an antioxidant film, which is known by OSP (Organic Solderability Preservatives) processing or the like. However, this antioxidant film may cause a decrease in solder wettability and a decrease in connectivity during the connection process. On the other hand, in this embodiment, when at least one of the first adhesive layer and the second adhesive layer is an adhesive layer containing a flux compound (for example, a thermosetting adhesive layer), the OSP treatment is not performed. Better connection reliability can be obtained.

  From the viewpoint of obtaining more excellent connection reliability, only one of the first adhesive layer and the second adhesive layer is an adhesive layer containing a flux compound (for example, a thermosetting adhesive layer), and the other is a flux compound. It is preferable that the adhesive layer does not contain (for example, a thermosetting adhesive layer).

  Next, among the resin compositions constituting the first adhesive layer and the second adhesive layer, the flux-containing composition and the flux-free composition will be described.

(Flux-containing composition)
The flux-containing composition is, for example, a thermosetting resin composition, and contains a thermosetting component and a flux compound. Examples of the thermosetting component include a thermosetting resin and a curing agent. Examples of the thermosetting resin include an epoxy resin, a phenol resin (excluding a case where it is contained as a curing agent), and a polyimide resin. Among them, the thermosetting resin is preferably an epoxy resin. Moreover, the film adhesive for semiconductors of the present embodiment may contain a polymer component having a weight average molecular weight of 10,000 or more and a filler, if necessary.

  Hereinafter, the flux-containing composition includes an epoxy resin (hereinafter, sometimes referred to as “component (a)”), a curing agent (hereinafter, sometimes referred to as “component (b)”), and a flux compound (hereinafter, referred to as “component”). And a polymer component having a weight average molecular weight of 10,000 or more (hereinafter, sometimes referred to as “component (d)”) and a filler (hereinafter, sometimes referred to as “( e) component ")).

[Component (a): epoxy resin]
As the epoxy resin, any resin having two or more epoxy groups in a molecule can be used without particular limitation. As the component (a), for example, bisphenol A epoxy resin, bisphenol F epoxy resin, naphthalene epoxy resin, phenol novolak epoxy resin, cresol novolak epoxy resin, phenol aralkyl epoxy resin, biphenyl epoxy resin, triphenyl Methane type epoxy resin, dicyclopentadiene type epoxy resin and various polyfunctional epoxy resins can be used. These can be used alone or as a mixture of two or more.

  From the viewpoint of suppressing the generation of volatile components by decomposing the component (a) at the time of connection at a high temperature, when the temperature at the time of connection is 250 ° C., the rate of thermal weight loss at 250 ° C. is 5% or less. It is preferable to use an epoxy resin, and when the temperature at the time of connection is 300 ° C., it is preferable to use an epoxy resin whose thermal weight loss rate at 300 ° C. is 5% or less.

  From the viewpoint of high heat resistance, the content of the component (a) is, for example, 5% by mass or more, preferably 10% by mass or more, and more preferably 15% by mass or more based on the total mass of the flux-containing composition. It is. The content of the component (a) is, for example, 75% by mass or less, 50% by mass or less, 45% by mass or less, or 35% by mass or less based on the total mass of the flux-containing composition from the viewpoint of film processability. From these viewpoints, the content of the component (a) is, for example, 5 to 75% by mass, 10 to 50% by mass, 15 to 45% by mass, or 15 to 35% by mass.

[(B) component: curing agent]
Examples of the component (b) include a phenolic resin-based curing agent, an acid anhydride-based curing agent, an amine-based curing agent, an imidazole-based curing agent, and a phosphine-based curing agent. When the component (b) contains a phenolic hydroxyl group, an acid anhydride, an amine or an imidazole, it exhibits a flux activity for suppressing the formation of an oxide film at the connection portion, and can improve connection reliability and insulation reliability. it can. From the viewpoint that such an effect can be more easily obtained, an imidazole-based curing agent is more preferably used. Hereinafter, each curing agent will be described.

(I) 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 a molecule. For example, a phenol novolak resin, a cresol novolak resin, a phenol aralkyl resin , Cresol naphthol formaldehyde polycondensate, triphenylmethane type polyfunctional phenol resin and various polyfunctional phenol resins can be used. 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 component (a) (the number of moles of the phenolic hydroxyl group contained in the phenolic resin-based curing agent / the number of moles of the epoxy group contained in the component (a)) is excellent in curability and adhesiveness. In light of storage stability and storage stability, 0.3 to 1.5 is preferable, 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, the unreacted phenolic hydroxyl group does not remain excessively, and the water absorption is reduced. It tends to be kept low and the insulation reliability tends to improve.

(Ii) Acid anhydride-based curing agent Examples of the acid anhydride-based curing agent include methylcyclohexanetetracarboxylic dianhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic dianhydride and ethylene glycol bis. Anhydrotrimellitate can be used. 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 component (a) (the number of moles of the acid anhydride group of the acid anhydride-based curing agent / the number of moles of the epoxy group of the component (a)) is good curability. From the viewpoint of adhesion, storage stability, and the like, 0.3 to 1.5 is preferable, 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, the unreacted acid anhydride does not remain excessively, and the water absorption is reduced. It tends to be kept low and the insulation reliability tends to improve.

(Iii) Amine curing agent As the amine curing agent, for example, dicyandiamide can be used.

  The equivalent ratio of the amine-based curing agent to the component (a) (the number of moles of active hydrogen groups contained in the amine-based curing agent / the number of moles of epoxy groups contained in the component (a)) is excellent in curability, adhesion, and storage. From the viewpoint of stability, 0.3 to 1.5 is preferable, 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, the unreacted amine does not remain excessively and the insulation reliability is improved. Tend to.

(Iv) 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-4,5- Examples thereof include dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and an adduct of an epoxy resin and imidazoles. Among these, from the viewpoints of excellent curability, storage stability and connection reliability, 1-cyanoethyl-2-undecylimidazole, 1-cyano-2-phenylimidazole, and 1-cyanoethyl-2-undecylimidazole trimellit. Tate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6- [2′-methylimidazolyl- (1 ′)]-ethyl-s-triazine, 2,4-diamino-6 [2'-ethyl-4'-methylimidazolyl- (1 ')]-ethyl-s-triazine, 2,4-diamino-6- [2'-methylimidazolyl- (1')]-ethyl-s-triazine Isocyanuric acid adduct, 2-phenylimidazole Isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole and 2-phenyl 4-Methyl-5-hydroxymethylimidazole is preferred. These can be used alone or in combination of two or more. Further, these may be used as a latent curing agent obtained by microencapsulation.

  The content of the imidazole-based curing agent is preferably 0.1 part by mass or more based on 100 parts by mass of the component (a). When the content of the imidazole-based curing agent is 0.1 parts by mass or more, the curability tends to be improved. Further, the content of the imidazole-based curing agent is preferably 20 parts by mass or less, and more preferably 10 parts by mass. When the content of the imidazole-based curing agent is 20 parts by mass or less, the fluidity of the flux-containing composition at the time of press bonding can be ensured, and the flux-containing composition between the connection parts can be sufficiently eliminated. As a result, the curing of the flux-containing composition while intervening between the solder and the connection portion is suppressed, and connection failure tends to hardly occur. From these viewpoints, 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, per 100 parts by mass of the component (a).

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

  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, per 100 parts by mass of the component (a). 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 flux-containing composition is cured before metal bonding is formed. And there is a tendency that poor connection hardly occurs.

  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.

  When the flux-containing composition contains a phenolic resin-based curing agent, an acid anhydride-based curing agent, or an amine-based curing agent as the component (b), it exhibits a flux activity for removing an oxide film and further improves connection reliability. Can be.

[Component (c): flux compound]
The component (c) is a compound having a flux activity, and functions as a flux compound in the flux-containing composition. As the component (c), a known component can be used without any particular limitation as long as it can reduce the oxide film on the surface such as solder to facilitate metal bonding. As the component (c), one type of flux compound may be used alone, or two or more types of flux compounds may be used in combination. However, the curing agent which is the component (b) is not included in the component (c).

  The flux compound preferably has a carboxyl group, more preferably two or more carboxyl groups, from the viewpoint of obtaining sufficient flux activity and obtaining more excellent connection reliability. Among them, compounds having two carboxyl groups are preferred. 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, the increase in the viscosity of the film adhesive for semiconductors during storage and connection work is further suppressed as compared with the case where a compound having three or more carboxyl groups is used. The connection reliability of the semiconductor device can be further improved.

As the flux compound having a carboxyl group, a compound having a group represented by the following formula (1) is preferably used.

In the formula (1), R ¹ represents a hydrogen atom or an electron donating group.

From the viewpoint of excellent reflow resistance and connection reliability, it is preferable that R ¹ has an electron donating property. In the present embodiment, the flux-containing composition contains an epoxy resin and a curing agent, and further contains, among the compounds having a group represented by the formula (1), a compound in which R ¹ is an electron donating group. This makes it possible to manufacture a semiconductor device that is excellent in reflow resistance and connection reliability even when applied as a film adhesive for a semiconductor in a flip-chip connection method in which metal bonding is performed.

  In order to improve the reflow resistance, it is necessary to suppress a decrease in adhesive strength after moisture absorption at a high temperature. Conventionally, a carboxylic acid has been used as a flux compound. However, the present inventors believe that a conventional flux compound causes a decrease in adhesive strength for the following reasons.

  Usually, the curing reaction proceeds by the reaction between the epoxy resin and the curing agent. At this time, carboxylic acid as a flux compound is taken into the curing reaction. That is, an ester bond may be formed by the reaction between the epoxy group of the epoxy resin and the carboxyl group of the flux compound. The ester bond is liable to undergo hydrolysis or the like due to moisture absorption, and the decomposition of the ester bond is considered to be a cause of a decrease in adhesive strength after moisture absorption.

On the other hand, among the compounds having a group represented by the formula (1), compounds having a group in which R ¹ is an electron donating group, that is, compounds having a carboxyl group having an electron donating group in the vicinity In the case of containing, while the flux activity is sufficiently obtained by the carboxyl group, and even when the above-mentioned ester bond is formed, the electron density of the ester bond part is increased by the electron donating group, and the decomposition of the ester bond is suppressed. Is done. In addition, it is considered that the presence of the substituent (electron-donating group) near the carboxyl group suppresses the reaction between the carboxyl group and the epoxy resin due to steric hindrance, and makes it difficult to form an ester bond.

For these reasons, when a flux-containing composition further containing a compound in which R ¹ is an electron donating group among the compounds having a group represented by the formula (1), a composition change due to moisture absorption or the like hardly occurs. , Excellent adhesion is maintained. In addition, it can be said that the above-mentioned effect is that the curing reaction between the epoxy resin and the curing agent is not easily inhibited by the flux compound, and the connection reliability due to the sufficient progress of the curing reaction between the epoxy resin and the curing agent by the effect can be said. The effect of improvement of can also be expected.

  When the electron donating property of the electron donating group becomes strong, the effect of suppressing the decomposition of the ester bond tends to be easily obtained. If the steric hindrance of the electron-donating group is large, the effect of suppressing the reaction between the carboxyl group and the epoxy resin described above is easily obtained. The electron donating group preferably has a good balance of electron donating properties and steric hindrance.

  Examples of the electron donating group include an alkyl group, a hydroxyl group, an amino group, an alkoxy group, and an alkylamino group. As the electron donating group, a group that does not easily react with other components (for example, the epoxy resin of the component (a)) is preferable, and specifically, an alkyl group, a hydroxyl group, or an alkoxy group is preferable, and an alkyl group is more preferable.

  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. As the carbon number of the alkyl group increases, the electron donating property and the steric hindrance tend to increase. Since an alkyl group having a carbon number in the above range is excellent in the balance between electron donating property and steric hindrance, the effect of the present invention is more remarkably exhibited by the alkyl group.

  Further, the alkyl group may be linear or branched, and is preferably linear. When the alkyl group is linear, the number of carbon atoms in the alkyl group is preferably equal to or less than the number of carbon atoms in the main chain of the flux compound from the viewpoint of the balance between electron donating properties and steric hindrance. For example, when the flux compound is a compound represented by the following formula (2) and the electron-donating group is a linear alkyl group, the carbon number of the alkyl group is determined by the carbon number of the main chain of the flux compound ( (n + 1) or less.

  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. As the carbon number of the alkoxy group increases, the electron donating property and the steric hindrance tend to increase. An alkoxy group having a carbon number in the above range is excellent in the balance between electron donating property and steric hindrance. Therefore, according to the alkoxy group, the effects of the present invention are more remarkably exhibited.

  Further, the alkyl group portion of the alkoxy group may be linear or branched, and is preferably linear. When the alkoxy group is linear, the number of carbon atoms in the alkoxy group is preferably equal to or less than the number of carbon atoms in the main chain of the flux compound from the viewpoint of the balance between electron donating properties and steric hindrance. For example, when the flux compound is a compound represented by the following formula (2) and the electron donating group is a linear alkoxy group, the number of carbon atoms of the alkoxy group is determined by the number of carbon atoms in the main chain of the flux compound ( (n + 1) or less.

  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 2 to 20 carbon atoms is preferable, and a dialkylamino group having 2 to 10 carbon atoms is more preferable. The alkyl group portion of the dialkylamino group may be linear or branched, and is preferably linear.

  As the flux compound having two carboxyl groups, a compound represented by the following formula (2) can be suitably used. According to 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 and R ² each independently represent a hydrogen atom or an electron donating group, and n represents 0 or an integer of 1 or more. A plurality of R ² may be the same or different from each other.

R ¹ has the same meaning as ^{R 1} in Formula (1). The electron donating property represented by R ² is the same as the above-described example of the electron donating group described as R ¹ . For the same reason as described in the formula (1), R ¹ in the formula (2) is preferably an electron donating group.

  N in the formula (2) is preferably 1 or more. When n is 1 or more, the flux compound hardly volatilizes even at a high temperature at the time of connection as compared with the case where n is 0, and the generation of voids can be further suppressed. Further, n in the formula (2) is preferably 15 or less, more preferably 11 or less, and may be 6 or 4 or less. When n is 15 or less, more excellent connection reliability can be obtained.

  Further, as the flux compound, a compound represented by the following formula (3) is more preferable. According to the compound represented by the following formula (3), the reflow resistance and connection reliability of the semiconductor device can be further improved.

In the formula (3), R ¹ and R ² each independently represent a hydrogen atom or an electron donating group, and m represents 0 or an integer of 1 or more.

  M in the formula (3) is preferably 10 or less, more preferably 5 or less, and still more preferably 3 or less. When m is 10 or less, more excellent connection reliability can be obtained.

In the formula (3), R ¹ and R ² may be a hydrogen atom or an electron donating group. From the viewpoint of obtaining more excellent connection reliability, at least one of R ¹ and R ² is preferably an electron donating group. When R ¹ is an electron donating group and R ² is a hydrogen atom, the melting point tends to be low, and the connection reliability of the semiconductor device may be able to be further improved. Further, when R ¹ and R ² are different electron donating groups, the melting point tends to be lower than when R ¹ and R ² are the same electron donating group. In some cases, reliability can be further improved.

In the formula (3), when R ¹ and R ² are the same electron donating group, they tend to have a symmetrical structure and a high melting point, but the effect of the present invention can be sufficiently obtained even in this case. In particular, when the melting point is sufficiently low, such as 150 ° C. or lower, even when R ¹ and R ² are the same group, the same connection reliability as when R ¹ and R ² are different groups can be obtained. .

  Examples of the flux compound include, for example, dicarboxylic acids selected from succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecandioic acid and dodecanedioic acid, and 2 of these dicarboxylic acids. A compound in which an electron donating group is substituted at the position can be used.

  The melting point of the flux compound is preferably 150 ° C. or lower, more preferably 140 ° C. or lower, and further preferably 130 ° C. or lower. Such a flux compound tends to sufficiently exhibit flux activity before a curing reaction between the epoxy resin and the curing agent occurs. Therefore, according to the film adhesive for semiconductors using such a flux compound, a semiconductor device having more excellent connection reliability can be realized. Further, the melting point of the flux compound is preferably at least 25 ° C, more preferably at least 50 ° C. Further, the flux compound is preferably a solid at room temperature (25 ° C.).

  The melting point of the flux compound can be measured using a general melting point measuring device. The sample whose melting point is to be measured is crushed into fine powder, and it is required to reduce the temperature deviation in the sample by using a small amount. As a container for the sample, a capillary tube having one end closed is often used. However, some measuring devices are sandwiched between two microscope cover glasses to form a container. If the temperature is rapidly increased, a temperature gradient will occur between the sample and the thermometer, causing a measurement error. Therefore, the heating at the time of measuring the melting point can be measured at a rate of 1 ° C. or less per minute. desirable.

  Since the material for measuring the melting point is prepared as a fine powder as described above, the sample before melting is opaque due to irregular reflection on the surface. Usually, the temperature at which the appearance of the sample starts to become transparent is defined as the lower limit of the melting point, and the temperature at which the sample is completely melted is defined as the upper limit. There are various types of measuring devices, but the most classical device is a device in which a capillary tube filled with a sample is attached to a double tube thermometer and heated in a warm bath. A highly viscous liquid is used as a hot bath liquid for the purpose of attaching a capillary tube to a double-tube thermometer, and concentrated sulfuric acid or silicon oil is often used, so that the sample comes near the reservoir at the tip of the thermometer. Attach. Further, as the melting point measuring device, a device which heats using a metal heat block and automatically determines the melting point while adjusting the heating while measuring the light transmittance can be used.

  In the present specification, a melting point of 150 ° C. or lower means that the upper limit of the melting point is 150 ° C. or lower, and a melting point of 25 ° C. or higher means that the lower limit of the melting point is 25 ° C. or higher. means.

  The content of the component (c) is preferably from 0.5 to 10% by mass, more preferably from 0.5 to 5% by mass, based on the total mass of the flux-containing composition.

[(D) component: a polymer component having a weight average molecular weight of 10,000 or more]
The flux-containing composition may contain a polymer component (component (d)) having a weight average molecular weight of 10,000 or more, if necessary. The flux-containing composition containing the component (d) is more excellent in heat resistance and film formability.

  As the component (d), 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 components (d) can be used alone or as a mixture or copolymer of two or more. However, the component (d) does not include a compound corresponding to the component (a) and a compound corresponding to the component (e).

  The weight average molecular weight of the component (d) is, for example, 10,000 or more, preferably 20,000 or more, and more preferably 30,000 or more. According to such a component (d), the heat resistance and the film forming property of the flux-containing composition can be further improved.

  Further, the weight average molecular weight of the component (d) is preferably 1,000,000 or less, more preferably 500,000 or less. According to the component (d), the heat resistance of the flux-containing composition can be further improved.

In addition, in this specification, the weight average molecular weight means a weight average molecular weight when measured in terms of polystyrene using high performance liquid chromatography (manufactured by Shimadzu Corporation, trade name: C-R4A). For the measurement, for example, the following conditions can be used.
Detector: LV4000 UV Detector (trade name, manufactured by Hitachi, Ltd.)
Pump: L6000 Pump (trade name, manufactured by Hitachi, Ltd.)
Column: Gelpack GL-S300MDT-5 (2 in total) (trade name, manufactured by Hitachi Chemical Co., Ltd.)
Eluent: THF / DMF = 1/1 (volume ratio) + LiBr (0.03 mol / L) + H3PO4 (0.06 mol / L)
Flow rate: 1 mL / min

When the flux-containing composition contains component (d), the content ratio _{C a} of the component (a) to the content _{C d} of the component (d) _C a / _{C d} (mass ratio), 0.01 It is preferably 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 adhesion can be obtained, and by setting the ratio C _a / C _d to 5 or less, better film formability can be obtained. .

[(E) component: filler]
The flux-containing composition may contain a filler (component (e)) as necessary. The viscosity of the flux-containing composition, the physical properties of a cured product of the flux-containing composition, and the like can be controlled by the component (e). Specifically, according to the component (e), it is possible to adjust the elastic modulus (for example, elastic modulus at 35 ° C.) of the film adhesive for semiconductor after curing, to suppress the generation of voids at the time of connection, and to contain the flux. The moisture absorption of the cured product of the composition can be reduced.

  Examples of the component (e) include an inorganic filler (inorganic particles) and an organic filler (organic particles). Examples of the inorganic filler include insulating inorganic fillers such as glass, silica, alumina, titanium oxide, mica, and boron nitride. Among them, at least one selected from the group consisting of silica, alumina, titanium oxide, and boron nitride is used. Preferably, at least one selected from the group consisting of silica, alumina and boron nitride is more preferable. The insulating inorganic filler may be a whisker. Examples of the whiskers include aluminum borate, aluminum titanate, zinc oxide, calcium silicate, and boron nitride. Examples of the organic filler include a resin filler (resin particles). Examples of the resin filler include polyurethane and polyimide. Resin fillers can provide flexibility at high temperatures such as 260 ° C. as compared with inorganic fillers, so they are suitable for improving reflow resistance, and also capable of imparting flexibility to improve film formability. effective. On the other hand, it is easy to adjust the elastic modulus to a desired range, and it is easy to adjust the viscosity of the film while suppressing the warpage, and it is possible to more sufficiently reduce the occurrence of voids, and furthermore, to have excellent connection reliability. From the viewpoint of obtaining, an inorganic filler is preferably used.

  The content of the inorganic filler is such that the elastic modulus can be easily adjusted to a desired range, and the occurrence of voids can be more sufficiently reduced while suppressing warpage, and further excellent connection reliability is obtained. From the viewpoint, it may be 50% by mass or more, 70% by mass or more, or 90% by mass or more based on the total mass of the component (e). The component (e) may consist essentially of only the inorganic filler. That is, the component (e) may not substantially contain an organic filler. “Substantially not contained” means that the content of the organic filler in the component (e) is less than 0.5% by mass based on the total mass of the component (e).

  From the viewpoint of further improving insulation reliability, the component (e) is preferably a filler having an insulating property (insulating filler). It is preferable that the flux-containing composition does not contain a conductive metal filler (metal particles) such as a silver filler and a solder filler, and a conductive filler (for example, an inorganic filler) such as carbon black.

  The content of the insulating filler is such that the elastic modulus can be easily adjusted to a desired range, and the occurrence of voids can be more sufficiently reduced while suppressing warpage, and further excellent connection reliability is obtained. From the viewpoint, the amount may be 50% by mass or more, 70% by mass or more, or 90% by mass or more based on the total mass of the component (e). The component (e) may consist essentially of an insulating filler. That is, the component (e) need not substantially contain a conductive filler. “Substantially not contained” means that the content of the conductive filler in the component (e) is less than 0.5% by mass based on the total mass of the component (e).

  The physical properties of the component (e) may be appropriately adjusted by surface treatment. The component (e) is preferably a surface-treated filler from the viewpoint of improving dispersibility or 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 type, an amino silane type or an acryl silane type is preferable from the viewpoint of easy surface treatment. As the surface treatment agent, at least one selected from the group consisting of a glycidyl-based compound, a phenylamino-based compound, and a (meth) acryl-based compound is preferable from the viewpoint of excellent dispersibility, fluidity, and adhesion. . As the surface treatment agent, from the viewpoint of excellent storage stability, at least one selected from the group consisting of a phenyl compound and a (meth) acrylic compound is preferable.

  The average particle size of the component (e) is preferably 1.5 μm or less from the viewpoint of preventing biting at the time of flip chip connection, and more preferably 1.0 μm or less from the viewpoint of excellent visibility (transparency).

  The content of the component (e) is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 20% by mass or more based on the total mass of the flux-containing composition. When the content of the component (e) is 5% by mass or more, the amount of expansion with respect to heat decreases. In addition, since the expansion of the minute voids can be suppressed, connection reliability (particularly, connection reliability when used in an environment such as a temperature cycle test) is excellent. The content of the component (e) is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less, based on the total mass of the flux-containing composition. When the content of the component (e) is 80% by mass or less, the resin is sufficiently removed at the time of thermocompression bonding, so that the connection reliability is more excellent. From these viewpoints, the content of the component (e) is preferably 5 to 80% by mass, more preferably 10 to 70% by mass, and more preferably 20 to 60% by mass, based on the total mass of the flux-containing composition. More preferably, it is mass%.

[Other ingredients]
The flux-containing composition may contain additives such as an antioxidant, a silane coupling agent, a titanium coupling agent, a leveling agent, and an ion trapping agent. These can 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.

(Flux-free composition)
The flux-free composition is, for example, a thermosetting resin composition. The flux-free composition contains substantially no flux compound. “Substantially free” means that the content of the flux compound in the flux-free composition is less than 0.5% by mass, based on the total mass of the flux-free composition.

  From the viewpoint that the effect of the present invention is remarkably obtained, the flux-free composition preferably has a curing reaction rate of 80% or more when held at 200 ° C. for 5 seconds. Such a flux-free composition includes, for example, a radical-curable adhesive. In the present embodiment, when one of the first adhesive layer and the second adhesive layer is an adhesive layer formed by a flux-containing composition, and the other is an adhesive layer formed by a flux-free composition, In particular, the effects of the present invention are more easily obtained. The reason why the effect of the present invention is remarkably obtained by such an adhesive is not clear, but the present inventors speculate as follows.

  That is, in a film adhesive containing a conventional flux compound, a radical curing system cannot be applied because a flux component inactivates radicals, and a cationic curing system using an epoxy or the like is applied. There were many things. In this curing system (reaction system), the curing progresses by a nucleophilic addition reaction, so that the curing speed is slow, and voids may be generated after pressure bonding. It is presumed that in the conventional film adhesive, a defect (for example, peeling of the semiconductor material at a reflow temperature of about 260 ° C., poor connection of the connection portion, or the like) occurred due to the void at the time of mounting. On the other hand, since the above-mentioned flux-free composition does not substantially contain a flux compound, the curing system can be a radical curing system, and a sufficient curing speed can be obtained. Therefore, by using the above-mentioned flux-free composition for the first adhesive layer or the second adhesive layer, even when pressure bonding is performed at a high temperature and in a short time, voids are less likely to occur, and the present invention The effect is presumed to be significant. Further, in the present embodiment, since a sufficient curing speed can be obtained, for example, even when solder is used in the connection portion, the film adhesive is cured in a temperature region lower than the solder melting temperature. Can be done. Therefore, it is possible to sufficiently suppress the occurrence of the connection failure due to the scattering and flow of the solder.

  Hereinafter, the flux-free composition requires a radical polymerizable compound (hereinafter, sometimes referred to as “component (A)”) and a thermal radical generator (hereinafter, sometimes referred to as “component (B)”). An embodiment will be described that contains a polymer component (hereinafter, sometimes referred to as a “component (C)”) and a filler (hereinafter, sometimes referred to as a “component (D)”), depending on the conditions.

[(A) component: radical polymerizable compound]
The component (A) is a compound capable of undergoing a radical polymerization reaction with the generation of radicals due to heat, light, radiation, electrochemical action, and the like. Examples of the component (A) include (meth) acrylic compounds and vinyl compounds. As the component (A), a (meth) acrylic compound is preferable from the viewpoint of excellent durability, electrical insulation, and heat resistance. The (meth) acrylic compound is not particularly limited as long as it is a compound having one or more (meth) acrylic groups ((meth) acryloyl groups) in a molecule, and examples thereof include bisphenol A type, bisphenol F type, naphthalene type, (Meth) acrylic compounds containing a phenol novolak type, cresol novolak type, phenol aralkyl type, biphenyl type, triphenylmethane type, dicyclopentadiene type, fluorene type, adamantane type or isocyanuric acid type skeleton; various polyfunctional (meth) ) Acrylic compounds (excluding (meth) acrylic compounds containing the skeleton) and the like can be used. Examples of the polyfunctional (meth) acrylic compound include pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, and trimethylolpropane di (meth) acrylate. As the component (A), one type can be used alone, or two or more types can be used in combination.

  The component (A) preferably has a bisphenol A type skeleton, a bisphenol F type skeleton, a naphthalene type skeleton, a fluorene type skeleton, an adamantane type skeleton or an isocyanuric acid type skeleton from the viewpoint of excellent heat resistance, and has a fluorene type skeleton. Is more preferable. The component (A) is more preferably a (meth) acrylate having any of the above-described skeletons.

  The component (A) is preferably solid at room temperature (25 ° C.). A solid is less likely to generate voids than a liquid, and the flux-free composition before curing (B stage) has a small viscosity (tack) and is excellent in handleability. Examples of the component (A) which is solid at room temperature (25 ° C.) include a (meth) acrylate having a bisphenol A type skeleton, a fluorene type skeleton, an adamantane type skeleton, or an isocyanuric acid type skeleton.

  The number of functional groups of the (meth) acryl group in the component (A) is preferably 3 or less. When the number of functional groups is large, the curing network proceeds rapidly, and unreacted groups may remain. On the other hand, when the number of functional groups is 3 or less, the number of functional groups does not become too large, and curing in a short time is apt to proceed sufficiently, so that a decrease in the curing reaction rate is easily suppressed.

  The molecular weight of the component (A) is preferably smaller than 2000, more preferably 1000 or less. The smaller the molecular weight of the component (A), the easier the reaction proceeds, and the higher the curing reaction rate.

  The content of the component (A) is 10% by mass or more based on the total mass of the flux-free composition, from the viewpoint that the curable component is suppressed from being reduced and the flow of the resin after curing is easily controlled sufficiently. Is preferable, and 15 mass% or more is more preferable. The content of the component (A) is 50% based on the total mass of the flux-free composition, from the viewpoint that the cured product is prevented from becoming too hard, and the warpage of the package tends to be suppressed. It is preferably at most 45 mass%, more preferably at most 45 mass%, even more preferably at most 40 mass%. From these viewpoints, the content of the component (A) is preferably from 10 to 50% by mass, more preferably from 10 to 45% by mass, and still more preferably from 15 to 40% by mass, based on the total mass of the flux-free composition. preferable.

  The content of the component (A) is preferably at least 0.01 part by mass with respect to 1 part by mass of the component (C), from the viewpoint that the curability is suppressed from decreasing and the adhesive strength is easily suppressed from decreasing. Preferably, it is 0.05 parts by mass or more, more preferably 0.1 parts by mass or more. The content of the component (A) is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, based on 1 part by mass of the component (C), from the viewpoint of easily suppressing a decrease in film formability. From these viewpoints, the content of the component (A) is preferably from 0.01 to 10 parts by mass, more preferably from 0.05 to 5 parts by mass, and more preferably from 0.1 to 5 parts by mass, per 1 part by mass of the component (C). 5 parts by mass is more preferred.

[(B) component: thermal radical generator]
The component (B) is not particularly limited as long as it functions as a curing agent for the component (A), but is preferably a thermal radical generator from the viewpoint of excellent handleability.

  Examples of the thermal radical generator include azo compounds and peroxides (such as organic peroxides). As the thermal radical generator, a peroxide is preferable, and an organic peroxide is more preferable. In this case, the radical reaction does not progress in the step of drying the solvent when forming the film, and the film is excellent in handleability and storage stability. Therefore, when a peroxide is used as the thermal radical generator, more excellent connection reliability is easily obtained. Examples of the organic peroxide include ketone peroxide, peroxyketal, hydroperoxide, dialkyl peroxide, diacyl peroxide, peroxydicarbonate, and peroxyester. As the organic peroxide, from the viewpoint of excellent storage stability, at least one selected from the group consisting of hydroperoxides, dialkyl peroxides and peroxyesters is preferable. Furthermore, as the organic peroxide, from the viewpoint of excellent heat resistance, at least one selected from the group consisting of hydroperoxides and dialkyl peroxides is preferable. Examples of the dialkyl peroxide include dicumyl peroxide and di-tert-butyl peroxide.

  The content of the component (B) is preferably at least 0.5 part by mass, more preferably at least 1 part by mass, based on 100 parts by mass of the component (A), from the viewpoint that curing can easily proceed sufficiently. The content of the component (B) is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, based on 100 parts by mass of the component (A). When the upper limit of the content of the component (B) is within the above range, the curing proceeds rapidly and the number of reaction points is suppressed from being increased, so that the molecular chain is shortened and unreacted groups are reduced. The remaining is suppressed. Therefore, when the upper limit of the content of the component (B) is within the above range, it is easy to suppress a decrease in reliability. From these viewpoints, the content of the component (B) is preferably from 0.5 to 10 parts by mass, more preferably from 1 to 5 parts by mass, per 100 parts by mass of the component (A).

[Component (C): polymer component]
The flux-free composition can further contain a polymer component. The component (C) includes an epoxy resin, a phenoxy resin, a polyimide resin, a polyamide resin, a polycarbodiimide resin, a cyanate ester resin, a (meth) acrylic resin, a polyester resin, a polyethylene resin, a polyether sulfone resin, a polyetherimide resin, and a polyvinyl acetal. Resins, urethane resins, acrylic rubbers, etc., among which epoxy resins, phenoxy resins, polyimide resins, (meth) acrylic resins, acrylic rubbers, cyanate ester resins, and polycarbodiimides from the viewpoint of excellent heat resistance and film formability. At least one selected from the group consisting of resins is preferred, and at least one selected from the group consisting of epoxy resins, phenoxy resins, polyimide resins, (meth) acrylic resins and acrylic rubbers is more preferred. The component (C) can be used alone or as a mixture or copolymer of two or more. However, the compound corresponding to the component (A) and the compound corresponding to the component (D) are not included in the component (C).

  The glass transition temperature (Tg) of the component (C) is preferably 120 ° C. or lower, more preferably 100 ° C. or lower, and further preferably 85 ° C. or lower, from the viewpoint of excellent adhesion of the film adhesive for semiconductor to a substrate or chip. preferable. When the thickness is within these ranges, the bumps formed on the semiconductor chip, the electrodes or the wiring patterns formed on the substrate, or the like can be easily embedded with the film adhesive for semiconductor (the curing reaction starts). It is easy to suppress the generation of voids due to the remaining air bubbles. The above Tg is measured using DSC (manufactured by PerkinElmer Japan Co., Ltd., product name: DSC-7 type) under the conditions of a sample amount of 10 mg, a heating rate of 10 ° C./min, and a measurement atmosphere of air. Tg.

  The weight average molecular weight of the component (C) is preferably 10,000 or more in terms of polystyrene, more preferably 30,000 or more, still more preferably 40,000 or more, and particularly preferably 50,000 or more, in order to show good film-forming properties by itself. When the weight average molecular weight is 10,000 or more, it is easy to suppress a decrease in film formability.

[(D) component: filler]
The flux-free composition is used to control the viscosity or the physical properties of the cured product, and to further suppress the generation of voids or the rate of moisture absorption when the semiconductor chip and the substrate or semiconductor chips are connected to each other, a filler. Further, it may be contained. As the component (D), the same filler as the filler exemplified as the component (e) in the flux-containing composition can be used. The same applies to preferred fillers. The preferred range of the content of the inorganic filler and the preferred range of the content of the insulating filler in the component (D) are the same.

  The content of the component (D) is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 20% by mass or more, based on the total mass of the flux-free composition. The content of the component (D) may be 30% by mass or more or 40% by mass or more. When the content of the component (D) is 5% by mass or more, the amount of expansion with respect to heat decreases. In addition, since the expansion of the minute voids can be suppressed, connection reliability (particularly, connection reliability when used in an environment such as a temperature cycle test) is excellent. The content of the component (D) is preferably 90% by mass or less, more preferably 80% by mass or less, further preferably 70% by mass or less, and further preferably 60% by mass or less, based on the total mass of the flux-free composition. Is more preferable. When the content of the component (D) is 90% by mass or less, the resin is sufficiently removed at the time of thermocompression bonding, so that connection reliability is more excellent. From these viewpoints, the content of the component (D) is preferably from 5 to 90% by mass, more preferably from 5 to 80% by mass, further preferably from 10 to 70% by mass, based on the total mass of the flux-free composition. Preferably, 20 to 60% by mass is even more preferable. The content of the component (D) may be 30 to 90% by mass or 40 to 80% by mass.

[Other ingredients]
A polymerizable compound (for example, a cationically polymerizable compound and an anionically polymerizable compound) other than the radically polymerizable compound may be blended in the flux-free composition. Further, the flux-free composition may contain other components similar to the flux-containing composition. These can 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.

  Above, the flux-free composition, a radical polymerizable compound, a thermal radical generator, and, if necessary, a polymer component and a filler, and described one embodiment containing a flux-free composition, It is not limited to the above embodiment.

  For example, the flux-free composition comprises the above-mentioned component (a) (epoxy resin), component (b) (curing agent), and, if necessary, component (d) (polymer having a weight average molecular weight of 10,000 or more). Component) and (e) a component (filler). When the flux-free composition is a resin composition containing these components, examples of the usable components (a), (b), (d) and (e), and examples of preferred compounds are as follows. Same as for the flux-containing composition. For example, the flux-free composition preferably contains an imidazole-based curing agent as a curing agent.

  From the viewpoint of high heat resistance, the content of the component (a) is, for example, 5% by mass or more, preferably 10% by mass or more, and more preferably 15% by mass, based on the total mass of the flux-free composition. That is all. The content of the component (a) is, for example, 75% by mass or less, 50% by mass or less, or 45% by mass or less based on the total mass of the flux-free composition from the viewpoint of film processability.

  The content of the component (b) (for example, the content of the imidazole-based curing agent) is preferably 0.1 part by mass or more based on 100 parts by mass of the component (a) from the viewpoint of improving curability. In addition, the content of the component (b) is preferably 20 parts by mass or less, and more preferably 10 parts by mass, from the viewpoint of suppressing poor connection.

As for the content of the component (d), the ratio C _a2 / C _d2 (mass ratio) of the content C _a2 of the component (a) to the content C _d2 of the component (d) is 0.01 to 5, 0.05. -3 or 0.1-2. By setting the ratio C _a2 / C _d2 to 0.01 or more, better curability and adhesion can be obtained, and by setting the ratio C _a2 / C _d2 to 5 or less, better film formability can be obtained. .

  The content of the component (e) is 5% based on the total mass of the flux-free composition from the viewpoint of superior connection reliability (particularly, connection reliability when used in an environment such as a temperature cycle test). It is preferably at least 10 mass%, more preferably at least 10 mass%, even more preferably at least 20 mass%. The content of the component (e) is preferably 80% by mass or less, based on the total mass of the flux-free composition, from the viewpoint that the resin can be sufficiently removed at the time of thermocompression bonding and connection reliability is more excellent. It is more preferably at most 60 mass%, more preferably at most 60 mass%.

The curing reaction rate when the flux-free composition is kept at 200 ° C. for 5 seconds is preferably 80% or more, more preferably 90% or more. If the curing reaction rate at 200 ° C. (less than the solder melting temperature) / 5 seconds is 80% or more, it is easy to prevent the solder from scattering and flowing at the time of connection (more than the solder melting temperature) and lowering the connection reliability. The curing reaction rate was determined by measuring the calorific value of a flux-free composition (an uncured flux-free layer) of 10 mg in an aluminum pan and then using DSC (trade name: DSC-7, manufactured by PerkinElmer Japan). Can be obtained by measuring Specifically, a measurement sample in which 10 mg of the flux-free composition (uncured flux-free layer) was placed in an aluminum pan was placed on a hot plate heated to 200 ° C., and after 5 seconds, the measurement sample was placed on the hot plate. Remove. The measurement sample after the heat treatment and the untreated measurement sample are each measured by DSC. From the obtained calorific value, the curing reaction rate is calculated by the following equation.
Curing reaction rate (%) = (1− [calorific value of measurement sample after heat treatment] / [calorific value of untreated measurement sample]) × 100

  When the flux-free composition contains an anionic polymerizable epoxy resin (particularly, an epoxy resin having a weight average molecular weight of 10,000 or more) together with the component (A), it may be difficult to adjust the curing reaction rate to 80% or more. When the flux-free composition contains the component (A), the content of the epoxy resin is preferably 20 parts by mass or less based on 80 parts by mass of the component (A), and the epoxy resin is not contained. Is more preferred.

  The adhesive layer (flux-free layer) formed of the flux-free composition can be pressure-bonded at a high temperature of 200 ° C. or higher. Further, in a flip chip package in which a connection is formed by melting a metal such as solder, more excellent curability is exhibited.

  The film adhesive for semiconductor of the present embodiment obtained using the flux-containing composition and / or the flux-free composition described above has an elastic modulus at 35 ° C. after curing of 3.0 to 5.0 GPa. . The modulus of elasticity of the film adhesive for semiconductors is determined, for example, by the type and compounding ratio of components constituting the film adhesive for semiconductors (for example, components constituting the first adhesive layer and components constituting the second adhesive layer). Can be adjusted by adjusting. Specifically, for example, it can be adjusted by the type and amount of the curable component, the type and amount of the polymer component, the amount of the filler, and the like. The elastic modulus of the film adhesive for semiconductors can be measured by the method described in Examples.

  The elastic modulus may be 3.5 GPa or more, or 4.0 GPa or more, from the viewpoint that the effects of the present invention become remarkable. The elastic modulus may be 4.7 GPa or less, or 4.4 GPa or less, from the viewpoint that the effects of the present invention become remarkable. That is, the elastic modulus is 3.0 to 4.7 GPa, 3.0 to 4.4 GPa, 3.5 to 5.0 GPa, 3.5 to 4.7 GPa, 3.5 to 4.4 GPa, 4.0. It may be -5.0 GPa, 4.0-4.7 GPa or 4.0-4.4 GPa.

  The content of the filler of the film adhesive for semiconductor is 30% by mass or more, 34% by mass or more, or 40% by mass based on the total mass of the film adhesive for semiconductor, from the viewpoint that the effects of the present invention become remarkable. Or less, and may be 60% by mass or less, 50% by mass or less, or 45% by mass or less.

  Of the first adhesive layer and the second adhesive layer, the content of the filler in one layer is 25% by mass, based on the total mass of the film adhesive for semiconductors, from the viewpoint that the effect of the present invention is remarkable. %, 35% by mass or 45% by mass or more, and may be 60% by mass or less, 55% by mass or less, or 50% by mass or less. Further, among the first adhesive layer and the second adhesive layer, the content of the filler in the other layer is, based on the total mass of the film adhesive for semiconductors, from the viewpoint that the effect of the present invention is remarkable. It may be 5% by mass or more, 10% by mass or more, or 15% by mass or more, and may be 30% by mass or less, 25% by mass or less, or 20% by mass or less.

  Regarding the thickness of the film adhesive for semiconductor, when the sum of the heights of the connection portions is x and the total thickness of the film adhesive for semiconductor is y, the relationship between x and y is From the viewpoint of the connectivity and the filling property of the adhesive, it is preferable to satisfy 0.70x ≦ y ≦ 1.3x, more preferably 0.80x ≦ y ≦ 1.2x. The total thickness of the film adhesive for semiconductors may be, for example, 10 to 100 μm, 10 to 80 μm, or 10 to 50 μm.

  The thickness of the first adhesive layer (for example, an adhesive layer containing a flux compound) may be, for example, 1 to 50 μm, 3 to 50 μm, 4 to 30 μm, or 5 to 20 μm. May be.

  The thickness of the second adhesive layer (for example, the adhesive layer containing no flux compound) may be, for example, 7 to 50 μm, 8 to 45 μm, or 10 to 40 μm.

  The ratio of the thickness of the second adhesive layer (for example, the adhesive layer containing no flux compound) to the thickness of the first adhesive layer (for example, the adhesive layer containing the flux compound) (thickness of second adhesive layer / second thickness) The thickness of one adhesive layer) may be, for example, 0.1 to 10.0, 0.5 to 6.0, or 1.0 to 4.0.

  The film adhesive for a semiconductor may further include a layer other than the first adhesive layer and the second adhesive layer, but preferably includes only the first adhesive layer and the second adhesive layer. . In addition, the film adhesive for semiconductor of the present embodiment is formed on the surface of the first adhesive layer opposite to the second adhesive layer, and / or with the first adhesive layer in the second adhesive layer. A base film and / or a protective film may be provided on the opposite surface.

  In the film adhesive for semiconductors, the first adhesive layer and the second adhesive layer may be adjacent to each other. In this case, it is preferable that the first adhesive layer and the second adhesive layer are formed so as not to be separated from each other. For example, the peel strength between the first adhesive layer and the second adhesive layer may be 10 N / m or more.

(Second embodiment)
In the film adhesive for semiconductors of the second embodiment, the elastic modulus at 35 ° C. after curing may not be 3.0 to 5.0 GPa. The details of the film adhesive for a semiconductor of the second embodiment are, for example, the content of the flux compound, except that the difference in the filler content between the first adhesive layer and the second adhesive layer and the like are different from those of the first embodiment. It may be the same as the film-form adhesive for semiconductor of the embodiment.

<Production method of film adhesive for semiconductor>
The film adhesive for semiconductor of the present embodiment is, for example, a first film adhesive having a first adhesive layer and a second film adhesive having a second adhesive layer are prepared. It can be obtained by laminating a first film adhesive having one adhesive layer and a second film adhesive having a second adhesive layer.

  As an adhesive layer, a film adhesive (first film adhesive and / or second film adhesive) including an adhesive layer formed of a flux-containing composition (an adhesive layer containing the flux-containing composition) is used. In the preparing step, for example, first, the component (a), the component (b) and the component (c), and other components such as the component (d) and the component (e) added as needed are added to an organic solvent. The resin varnish (coating varnish) is prepared by dissolving or dispersing the mixture by stirring, mixing, kneading, or the like. Then, after applying a resin varnish to the release-treated base film using a knife coater, a roll coater, an applicator, etc., the organic solvent is reduced by heating, and the flux-containing composition is applied onto the base film. Can be formed.

  As the organic solvent used for preparing the resin varnish, those having properties capable of uniformly dissolving or dispersing each component are preferable, for example, dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, 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. The stirring and mixing and kneading at the time of preparing the resin varnish can be performed using, for example, a stirrer, a mill, 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.Polyolefin films such as polypropylene films and polymethylpentene films, polyethylene terephthalate films, 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 film composed of these films, and may be a multilayer film composed of two or more materials.

  The drying conditions when the organic solvent is volatilized from the resin varnish applied to the base film are preferably set to conditions under which the organic solvent is sufficiently volatilized, specifically, 50 to 200 ° C. for 0.1 to 90 minutes. Is preferably performed. The organic solvent is preferably removed up to 1.5% by mass or less based on the total amount of the first film adhesive as long as the void or the viscosity adjustment after mounting is not affected.

  Film adhesive (first film adhesive and / or second film adhesive) having an adhesive layer formed of a flux-free composition (adhesive layer containing a flux-free composition) as the adhesive layer In the step of preparing component (A), for example, component (A) and component (B), and other components such as component (C) added as needed, component (a) and component (b), and Accordingly, an adhesive layer containing a flux-free composition can be formed on a base film by the same method as that for the first adhesive layer except that another component such as the component (d) is used.

  As a method of bonding the first film adhesive and the second film adhesive, for example, a method such as hot press, roll lamination, vacuum lamination and the like can be mentioned. Lamination may be performed, for example, under a heating condition of 30 to 120 ° C.

  The film adhesive for semiconductor of the present embodiment is, for example, after forming one of the first adhesive layer or the second adhesive layer on the base film, the obtained first adhesive layer or the second adhesive layer It may be obtained by forming the other of the first adhesive layer and the second adhesive layer on the layer. The first adhesive layer and the second adhesive layer may be formed by the same method as the above-described method for forming the first adhesive layer and the second adhesive layer in the production of the base material-attached film adhesive.

<Semiconductor device>
The semiconductor device according to the present embodiment will be described below with reference to FIGS. FIG. 1 is a schematic sectional view showing one embodiment of the semiconductor device of the present invention. As shown in FIG. 1A, a semiconductor device 100 includes a semiconductor chip 10 and a substrate (circuit wiring substrate) 20 facing each other, and a wiring 15 arranged on the surfaces of the semiconductor chip 10 and the substrate 20 facing each other. A connection bump 30 for connecting the wiring 15 of the semiconductor chip 10 and the substrate 20 to each other, and an adhesive (for example, a flux-containing composition and a flux-free composition) filled in the gap between the semiconductor chip 10 and the substrate 20 without gaps And a sealing portion 40 made of a cured product of the above. The semiconductor chip 10 and the substrate 20 are flip-chip connected by the wiring 15 and the connection bump 30. The wiring 15 and the connection bump 30 are sealed with a cured product of an adhesive and are shielded from an external environment. The sealing portion 40 has an upper portion 40a containing a cured product of the flux-containing composition or the flux-free composition, and a lower portion 40b containing a cured product of the flux-containing composition or the flux-free composition. . The upper part 40a and the lower part 40b contain different cured products of the thermosetting resin composition.

  As shown in FIG. 1B, the semiconductor device 200 includes a semiconductor chip 10 and a substrate 20 facing each other, bumps 32 respectively arranged on surfaces of the semiconductor chip 10 and the substrate 20 facing each other, And a sealing portion 40 made of a cured product of an adhesive (for example, a flux-containing composition and a flux-free composition) filled in the gaps between the substrates 20 without any gap. The semiconductor chip 10 and the substrate 20 are flip-chip connected by connecting the opposing bumps 32 to each other. The bump 32 is sealed with a cured product of an adhesive and is shielded from an external environment. The sealing portion 40 has an upper portion 40a containing a cured product of the flux-containing composition or the flux-free composition, and a lower portion 40b containing a cured product of the flux-containing composition or the flux-free composition. . The upper part 40a and the lower part 40b contain different cured products of the thermosetting resin composition.

  FIG. 2 is a schematic sectional view showing another embodiment of the semiconductor device of the present invention. As shown in FIG. 2A, the semiconductor device 300 is the same as the semiconductor device 100 except that two semiconductor chips 10 are flip-chip connected by wirings 15 and connection bumps 30. As shown in FIG. 2B, the semiconductor device 400 is similar to the semiconductor device 200 except that two semiconductor chips 10 are flip-chip connected by bumps 32.

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

  The substrate 20 is not particularly limited as long as it is a circuit board. An unnecessary portion of a metal film is etched on the surface of an insulating substrate mainly composed of glass epoxy, polyimide, polyester, ceramic, epoxy, bismaleimide triazine, or the like. A circuit board having wirings (wiring patterns) 15 formed by removal; a circuit board having wirings 15 formed on the surface of the insulating substrate by metal plating or the like; and a wiring by printing a conductive substance on the surface of the insulating substrate. For example, a circuit board on which the substrate 15 is formed can be used.

  Connection parts such as the wiring 15 and the bumps 32 are mainly composed of gold, silver, copper, solder (for example, tin-silver, tin-lead, tin-bismuth, tin-copper, tin-silver-copper, etc.) ), Nickel, tin, lead and the like, and may contain a plurality of metals.

  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, which are inexpensive materials, are preferred, copper and solder are more preferred, and solder is even more preferred. When an oxide film is formed on the surface of a metal at room temperature, productivity and cost may increase.From the viewpoint of suppressing the formation of an oxide film, gold, silver, copper, and solder are preferable, and gold and silver are preferable. , Solder is more preferable, and gold and silver are more preferable.

  Gold, silver, copper, solder (main components are, for example, tin-silver, tin-lead, tin-bismuth, tin-copper, etc.), tin, nickel and the like are mainly provided on the surfaces of the wirings 15 and the bumps 32. The metal layer as a component may be formed by plating, for example. 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.

  Further, the semiconductor device of the present embodiment may have a plurality of stacked structures (packages) as shown in the semiconductor devices 100 to 400. In this case, the semiconductor devices 100 to 400 are made of gold, silver, copper, solder (for example, tin-silver, tin-lead, tin-bismuth, tin-copper, tin-silver-copper, etc.), tin, nickel They may be electrically connected to each other by bumps, wirings, or the like including these.

  As a technique for stacking a plurality of semiconductor devices, for example, a TSV (Through-Silicon Via) technique can be given as shown in FIG. FIG. 3 is a schematic sectional view showing another embodiment of the semiconductor device of the present invention, which is a semiconductor device using the TSV technology. In the semiconductor device 500 shown in FIG. 3, the wiring 15 formed on the interposer 50 is connected to the wiring 15 of the semiconductor chip 10 via the connection bumps 30, so that the semiconductor chip 10 and the interposer 50 are flip-chip connected. ing. A space between the semiconductor chip 10 and the interposer 50 is filled with a cured product of an adhesive (for example, a flux-containing composition and a flux-free composition) without gaps, and forms a sealing portion 40. On the surface of the semiconductor chip 10 opposite to the interposer 50, the semiconductor chip 10 is repeatedly laminated via the wiring 15, the connection bump 30, and the sealing portion 40. The wirings 15 on the pattern surface on the front and back sides of the semiconductor chip 10 are connected to each other by through electrodes 34 filled in holes passing through the inside of the semiconductor chip 10. The material of the through electrode 34 may be copper, aluminum, or the like.

  With such a TSV technology, it is possible to acquire signals 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 10, the distance between the opposing semiconductor chips 10 and the distance between the semiconductor chip 10 and the interposer 50 can be shortened, and flexible connection is possible. The film adhesive for semiconductor of the present embodiment can be applied as a film adhesive for semiconductor between the opposed semiconductor chips 10 and between the semiconductor chip 10 and the interposer 50 in such TSV technology.

  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 film adhesive for semiconductor of the present embodiment can be applied to a case where such a semiconductor chip is directly mounted on a motherboard. In addition, the film adhesive for semiconductors of the present embodiment can be applied to a case where two printed circuit boards are laminated and a gap between the substrates is sealed.

<Semiconductor device manufacturing method>
Regarding the method for manufacturing a semiconductor device of the present embodiment, referring to FIG. 4, the first adhesive layer is an adhesive layer formed of a flux-containing composition, and the second adhesive layer is formed of a flux-free composition. The case where the adhesive layer is used will be described as an example. However, even when the thermosetting resin compositions forming the first adhesive layer and the second adhesive layer are different, a semiconductor device can be manufactured in the same manner.

  4A to 4C are diagrams schematically showing one embodiment of a method for manufacturing a semiconductor device according to the present invention. FIGS. 4A, 4B, and 4C showing each step are shown in FIGS. 2 shows a cross section of FIG.

  First, as shown in FIG. 4A, a solder resist 60 having an opening at a position where the connection bump 30 is to be formed is formed on the substrate 20 having the wiring 15. This solder resist 60 does not necessarily need to be provided. However, by providing the solder resist on the substrate 20, the occurrence of bridges between the wirings 15 can be suppressed, and the connection reliability and insulation reliability can be improved. The solder resist 60 can be formed using, for example, a commercially available solder resist ink for a package. Specific examples of commercially available solder resist inks for packaging include SR series (trade name, manufactured by Hitachi Chemical Co., Ltd.) and PSR4000-AUS series (trade name, manufactured by Taiyo Ink Mfg. Co., Ltd.).

  Next, as shown in FIG. 4A, connection bumps 30 are formed in the openings of the solder resist 60. Then, as shown in FIG. 4B, on the substrate 20 on which the connection bumps 30 and the solder resist 60 are formed, the surface on the second adhesive layer 41b side containing the flux-free composition becomes the substrate 20 side. As described above, the film adhesive for semiconductor (hereinafter, sometimes referred to as “film adhesive”) 41 of the present embodiment is attached. The attachment of the film adhesive 41 can be performed by hot press, roll lamination, vacuum lamination, or the like. The supply area and the thickness of the film adhesive 41 are appropriately set according to the size of the semiconductor chip 10 and the substrate 20, the height of the connection bump 30, and the like. The film adhesive 41 may be attached such that the surface on the first adhesive layer 41a side containing the flux-containing composition is on the substrate 20 side.

  After adhering the film adhesive 41 to the substrate 20 as described above, the wiring 15 of the semiconductor chip 10 and the connection bump 30 are aligned using a connection device such as a flip chip bonder. Subsequently, the semiconductor chip 10 and the substrate 20 are pressure-bonded while being heated at a temperature equal to or higher than the melting point of the connection bumps 30, and as shown in FIG. The gap between the semiconductor chip 10 and the substrate 20 is sealed and filled by the sealing portion 40 made of a cured product of the adhesive 41. Thus, a semiconductor device 600 is obtained.

  The crimping time may be, for example, 5 seconds or less. In the present embodiment, since the film adhesive 41 of the above-described embodiment is used, a semiconductor device having excellent connection reliability can be obtained even if the pressure bonding time is 5 seconds or less.

  In the method for manufacturing a semiconductor device according to the present embodiment, the connection bump 30 is melted by performing a heat treatment in a reflow furnace by temporarily fixing after the alignment (with the film-like adhesive for a semiconductor interposed therebetween) and by performing a heat treatment in a reflow furnace. The chip 10 and the substrate 20 may be connected. At the temporary fixing stage, it is not always necessary to form a metal joint. Therefore, compared to the above-mentioned method of crimping while heating, crimping with a low load, a short time, and a low temperature is sufficient, thereby improving productivity and connecting. Deterioration of the part can be suppressed.

  After the semiconductor chip 10 and the substrate 20 are connected, a heat treatment may be performed in an oven or the like to further improve connection reliability and insulation reliability. The heating temperature is preferably a temperature at which the curing of the film adhesive proceeds, and more preferably a temperature at which the film adhesive is completely cured. The heating temperature and the heating time are appropriately set.

  In the method for manufacturing a semiconductor device of the present embodiment, the substrate 20 may be connected after the film adhesive 41 is attached to the semiconductor chip 10.

  From the viewpoint of improving productivity, a semiconductor film-like adhesive is supplied to a semiconductor wafer to which a plurality of semiconductor chips 10 are connected, and then diced into individual pieces, thereby bonding the semiconductor film-like adhesive onto the semiconductor chip 10. A structure to which the agent has been supplied may be obtained. The film adhesive for semiconductor may be supplied so as to embed the wirings, bumps, and the like on the semiconductor chip 10 by a bonding method such as hot press, roll lamination, and vacuum lamination. In this case, since the supply amount of the resin is constant, productivity is improved, and it is possible to suppress generation of voids and reduction in dicing performance due to insufficient embedding.

  The connection load is set in consideration of the variation in the number and height of the connection bumps 30 and the amount of deformation of the connection bumps 30 due to the pressure or the wiring that receives the bumps at the connection portions. The connection temperature is preferably such that the temperature of the connection portion is equal to or higher than the melting point of the connection bump 30, but may be any temperature at which the metal junction of each connection portion (bump and wiring) is formed. When the connection bump 30 is a solder bump, the temperature is preferably about 240 ° C. or higher.

  The connection time at the time of connection differs depending on the constituent metal of the connection portion, but it is preferable that the connection time is shorter from the viewpoint of improving productivity. When the connection bump 30 is a solder bump, the connection time is preferably 20 seconds or less, more preferably 10 seconds or less, and even more preferably 5 seconds or less. In the case of copper-copper or copper-gold metal connection, the connection time is preferably 60 seconds or less.

  Even in the flip-chip connection portions having various package structures described above, the film adhesive for semiconductor of the present embodiment exhibits excellent reflow resistance and connection reliability.

  As described above, the preferred embodiments of the present invention have been described, but the present invention is not limited to the above embodiments.

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

<Preparation of single-layer films A and B>
The compounds used for producing the single-layer film A having the flux-containing layer and the single-layer film B having the flux-free layer are shown below.
(A) Epoxy resin / triphenolmethane skeleton-containing polyfunctional solid epoxy (manufactured by Mitsubishi Chemical Corporation, trade name: jER1032H60)
・ Bisphenol F type liquid epoxy (Mitsubishi Chemical Corporation, trade name: jERYL983U)
(B) Curing agent · 2,4-diamino-6- [2′-methylimidazolyl- (1 ′)]-ethyl-s-triazine isocyanuric acid adduct (trade name: 2MAOK-PW, manufactured by Shikoku Chemicals Co., Ltd.) )
(C) Flux compound glutaric acid (manufactured by Tokyo Chemical Industry Co., Ltd., melting point: about 98 ° C)
・ 2-methylglutaric acid (Sigma-Aldrich, melting point about 78 ° C)
(D) Polymer component / phenoxy resin (trade name: ZX1356-1, Tg: about 71 ° C, weight average molecular weight Mw: about 63000, manufactured by Toto Kasei Co., Ltd.)
(E) Filler / silica filler (trade name: SE2050, manufactured by Admatechs Co., Ltd., average particle size: 0.5 μm)
・ Epoxysilane surface treated filler (manufactured by Admatechs Co., Ltd., trade name: SE2050-SEJ, average particle size: 0.5 μm)
-Methacryl surface treated nano silica filler (manufactured by Admatechs Co., Ltd., trade name: YA050C-MJE, average particle size: about 50 nm)
-Organic filler (resin filler, manufactured by Rohm and Haas Japan KK, EXL-2655: core-shell type organic fine particles)

  In the production of the single-layer film A, the epoxy resin, the curing agent, the flux compound, the polymer component, and the filler in the compounding amounts (unit: parts by mass) shown in Table 1 were used for NV value ([mass of paint after drying] / [ (Mass of coating before drying) × 100) was added to the organic solvent (methyl ethyl ketone) so as to be 50%. Thereafter, beads having a diameter of 1.0 mm and beads having a diameter of 2.0 mm were added in the same mass as the solid content (epoxy resin, curing agent, flux compound, polymer component and filler), and a bead mill (Fritsch Japan K.K., planetary-type fine pulverization) was added. The mixture was stirred for 30 minutes using a machine P-7). After stirring, the beads were removed by filtration to produce a coating varnish. In the preparation of the single-layer film B, a coating varnish was prepared in the same manner as in the case of the single-layer film A, except that the flux compound was not used.

  The obtained coating varnish is coated on a base film (manufactured by Teijin Dupont Film Co., Ltd., trade name: Purex A54) using a small precision coating device (Narui Seiki) and a clean oven (ESPEC Co., Ltd.) (A-1), (A-1), (A-2), (A-3), (A-4), (B-1) and (BB-2) was obtained. The thickness of the flux-containing layer in the single-layer film A and the thickness of the flux-free layer in the single-layer film B were both 20 μm.

<Preparation of single-layer film C>
The compounds used for producing the single-layer film C having the flux-free layer are shown below.
(A) (meth) acrylic compound • Acrylate having a fluorene-type skeleton (trade name: EA-0200, manufactured by Osaka Gas Chemical Co., Ltd., bifunctional group)

(B) Thermal radical generator dicumyl peroxide (trade name: Parkmill (registered trademark) D, manufactured by NOF Corporation)
-1,4-bis-((tert-butylperoxy) diisopropyl) benzene (trade name: Perbutyl (registered trademark) P, manufactured by NOF Corporation)

(C) Polymer component-Acrylic resin (trade name: KH-CT-865, manufactured by Hitachi Chemical Co., Ltd., weight average molecular weight Mw: 100,000, Tg: 10 ° C)

(D) Filler The same filler as the filler (component (e)) used for producing the single-layer films A and B was used.

  The (meth) acrylic compound, the polymer component, and the filler in the compounding amounts (unit: parts by mass) shown in Table 1 were added to the organic solvent (methyl ethyl ketone) so that the NV value became 50%. Thereafter, beads having a diameter of 1.0 mm and beads having a diameter of 2.0 mm were added in the same mass as the solid content ((meth) acrylic compound, polymer component and filler), and a bead mill (Fritsch Japan K.K., planetary pulverizer P) was added. The mixture was stirred at -7) for 30 minutes. After stirring, the beads were removed by filtration. Next, a thermal radical generator was added to the obtained mixture, followed by stirring and mixing to prepare a coating varnish.

  The obtained coating varnish is coated on a base film (manufactured by Teijin Dupont Film Co., Ltd., trade name: Purex A54) using a small precision coating device (manufactured by Yasui Seiki Co., Ltd.), and a clean oven ( It was dried (80 ° C./10 min) by ESPEC Co., Ltd. to obtain single-layer films (C-1), (C-2), (C-3) and (C-4) shown in Table 1. The thickness of the flux-free layer in the single-layer film C was 20 μm in each case.

<Preparation of two-layer film>
(Examples 1 to 6 and Comparative Examples 1 to 4)
Of the single-layer films produced above, two identical or different films were laminated at 50 ° C. to produce a film adhesive having a total thickness of 40 μm. The combinations of the single-layer films were as shown in Table 1. In addition, when the same film is used, the second adhesive layer does not exist. Therefore, Table 1 shows only the first adhesive layer.

<Evaluation>
By the methods described below, the film adhesives obtained in Examples and Comparative Examples and the semiconductor devices manufactured using the film adhesives were measured for elastic modulus, chip warpage evaluation, initial connectivity, and void evaluation. And a temperature cycle test evaluation. Table 1 shows the results.

(Elastic modulus measurement)
By cutting out the film adhesive obtained in the example or the comparative example to a predetermined size (length 40 mm × width 4.0 mm × thickness 0.06 mm) and curing it in a clean oven (manufactured by ESPEC Corporation), A test sample was obtained. The curing condition was 240 ° C. for 1 hour.

  The elastic modulus of the test sample was measured using a dynamic viscoelasticity measurement device (trade name: Rheogel-E4000, manufactured by UBM Corporation).

(Evaluation of chip warpage)
Using a vacuum laminator (produced by NPC Corporation, trade name: LM-50X50-S), the film-like adhesive obtained in the example or the comparative example was silicon chip (length 10 mm × width 10 mm × thickness). 0.05 mm, oxide film coating). Next, the sample on which the film adhesive was laminated was cured in a clean oven (manufactured by ESPEC Corporation) to obtain a test sample. The curing condition was 240 ° C. for 1 hour.

  Moire measurement was performed using a 3D heating surface profile measuring device Thermoray PS200S (manufactured by akrometrix), and the result of warpage was smaller than 130 μm as “A”; The thing was set to "C" and the chip warpage was evaluated. Specifically, the test sample was placed under the glass having vertical stripes, light was irradiated from an oblique direction, interference fringes were measured with a camera, and the test samples were analyzed to measure the warpage of the test sample.

(Evaluation of initial connectivity)
The film-like adhesive prepared in the example or the comparative example was cut into a predetermined size (8 mm long × 8 mm wide × 40 μm thick) to prepare a sample for evaluation. Next, the evaluation sample was attached on a glass epoxy substrate (glass epoxy substrate: 420 μm thickness, copper wiring: 9 μm thickness), and a semiconductor chip with solder bumps (chip size: 7.3 mm long × 7.3 mm wide × thickness) 0.15 mm, bump height: copper pillar + solder about 40 μm in total, bump number: 328) were mounted using a flip mounting apparatus “FCB3” (trade name, manufactured by Panasonic Corporation). The mounting conditions were a crimping head temperature of 350 ° C., a crimping time of 3 seconds, and a crimping pressure of 0.5 MPa. Thus, a semiconductor device in which the glass epoxy substrate and the semiconductor chip with solder bumps were daisy-chain-connected was manufactured as in FIG. In addition, the evaluation samples of Examples 1 to 5 and Comparative Examples 1 and 4 were stuck on a glass substrate so that the second adhesive layer was in contact with the glass epoxy substrate.

  The initial continuity after mounting was evaluated by measuring the connection resistance value of the obtained semiconductor device using a multimeter (trade name: R6871E, manufactured by Advantest Corporation). When the connection resistance value is 10.0Ω or more and 13.5Ω or less, the connection is “A” (good). When the connection resistance value is more than 13.5Ω and 20Ω or less, the connection is “B” (bad). When the resistance value was larger than 20Ω, when the connection resistance value was less than 10Ω, and when the resistance value was not displayed due to poor connection, all were evaluated as connectivity “C” (defective).

(Void evaluation)
With respect to the semiconductor device manufactured by the above method, an external appearance image is taken by an ultrasonic diagnostic imaging apparatus (trade name: Insight-300, manufactured by Insight Co., Ltd.), and a scanner GT-9300UF (trade name, manufactured by Seiko Epson Corporation) is used. An image of the adhesive portion on the chip (a portion made of a cured product of a film adhesive for a semiconductor) is captured, and the void portion is identified by color tone correction and two-gradation using image processing software Adobe Photoshop (registered trademark). The ratio occupied by the void portion was calculated from the histogram. Assuming that the area of the adhesive portion on the chip is 100%, "A" indicates that the void generation rate is 5% or less, "B" indicates that the void generation rate is more than 5% and 10% or less, and "B" indicates that the void generation rate is more than 10%. C ".

(Temperature cycle test evaluation (TCT resistance evaluation))
The semiconductor device manufactured by the above method was molded under the conditions of 180 ° C., 6.75 MPa, and 90 seconds using a sealing material (trade name: CEL9750ZHF10, manufactured by Hitachi Chemical Co., Ltd.). Next, after-curing was performed in a clean oven (manufactured by ESPEC Corporation) at 175 ° C. for 5 hours to obtain a package. Next, this package was connected to a cooling / heating cycle tester (manufactured by Kusumoto Kasei Co., Ltd., trade name: THERMAL SHOCK CHAMBER NT1200). A change in connection resistance after 1000 cycles was repeated with 1 cycle of 15 ° C./2 minutes at 25 ° C. being evaluated. "A" indicates that there was no significant change after 1000 cycles compared to the initial resistance value waveform (no difference or a difference of less than 1 Ω), and "B" indicates a difference of 1 Ω or more. "

  It was confirmed that the film adhesive for semiconductors of the examples had reduced warpage, sufficiently suppressed generation of voids, good electrical connectivity, and excellent electrical connectivity even after the temperature cycle test.

  DESCRIPTION OF SYMBOLS 10 ... Semiconductor chip, 15 ... Wiring (connection part), 20 ... Substrate (wiring circuit board), 30 ... Connection bump, 32 ... Bump (connection part), 34 ... Through-electrode, 40 ... Sealing part, 41 ... For semiconductor Film adhesive, 50 interposer, 60 solder resist, 100, 200, 300, 400, 500, 600 semiconductor device.

Claims (18)

A first adhesive layer, comprising a second adhesive layer provided on the first adhesive layer,
A film adhesive for semiconductors having an elastic modulus at 35 ° C. after curing of 3.0 to 5.0 GPa. A film adhesive for a semiconductor containing a filler,
A first adhesive layer, comprising a second adhesive layer provided on the first adhesive layer,
The film adhesive for a semiconductor, wherein the content of the filler is 30 to 60% by mass based on the total mass of the film adhesive for a semiconductor.   The film adhesive for semiconductors according to claim 1 or 2, wherein at least one of the first adhesive layer and the second adhesive layer is a thermosetting adhesive layer.   The film adhesive for a semiconductor according to any one of claims 1 to 3, wherein both the first adhesive layer and the second adhesive layer are thermosetting adhesive layers.   The film adhesive for semiconductors according to any one of claims 1 to 4, wherein at least one of the first adhesive layer and the second adhesive layer is a thermosetting adhesive layer containing a flux compound.   The film adhesive for a semiconductor according to claim 5, wherein the flux compound has a carboxyl group.   The film adhesive for semiconductors according to claim 5, wherein the flux compound has two or more carboxyl groups. The film adhesive for a semiconductor according to any one of claims 5 to 7, wherein the flux compound is a compound represented by the following formula (2).

[In the formula (2), R ¹ and R ² each independently represent a hydrogen atom or an electron donating group, and n represents 0 or an integer of 1 or more. A plurality of R ² may be the same or different from each other. ]   The film adhesive for a semiconductor according to any one of claims 5 to 8, wherein a melting point of the flux compound is 150 ° C or less. One of the first adhesive layer and the second adhesive layer is a thermosetting adhesive layer containing no flux compound,
The film adhesive for semiconductors according to any one of claims 5 to 9, wherein the thermosetting adhesive layer containing no flux compound contains a radical polymerizable compound and a thermal radical generator.   The film adhesive for semiconductor according to claim 10, wherein the thermal radical generator is a peroxide.   The film adhesive for a semiconductor according to claim 10, wherein the radical polymerizable compound is a (meth) acrylic compound.   The film adhesive for semiconductors according to claim 12, wherein the (meth) acrylic compound has a fluorene-type skeleton. One of the first adhesive layer and the second adhesive layer is a thermosetting adhesive layer containing no flux compound,
The film adhesive for semiconductors according to any one of claims 5 to 9, wherein the thermosetting adhesive layer containing no flux compound contains an epoxy resin.   15. The film adhesive for semiconductor according to claim 14, wherein the thermosetting adhesive layer containing no flux compound further contains a latent curing agent.   The film adhesive for a semiconductor according to claim 15, wherein the latent curing agent is an imidazole-based curing agent. A method of manufacturing a semiconductor device in which connection portions of a semiconductor chip and a wiring circuit board are electrically connected to each other, or a semiconductor device in which connection portions of a plurality of semiconductor chips are electrically connected to each other,
A method for manufacturing a semiconductor device, comprising a step of sealing at least a part of the connection portion using the film adhesive for a semiconductor according to claim 1. A semiconductor device in which respective connection portions of the semiconductor chip and the wiring circuit board are electrically connected to each other, or a semiconductor device in which respective connection portions of a plurality of semiconductor chips are electrically connected to each other,
A semiconductor device, wherein at least a part of the connection part is sealed with a cured product of the film adhesive for semiconductor according to any one of claims 1 to 16.

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