JP2022186809A - Film-like adhesive for semiconductor, method for manufacturing semiconductor device and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film-like adhesive for a semiconductor which suppresses warpage of a bottom wafer even in mounting at a wafer level, and can obtain excellent connection reliability without voids after mounting even when crimping time is shortened.

SOLUTION: A film-like adhesive for a semiconductor containing a filler includes a first adhesive layer, and a second adhesive layer provided on the first adhesive layer, wherein the one of the first adhesive layer and the second adhesive layer is a thermosetting adhesive layer containing a flux compound, the other 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 is composed of a radical curable adhesive, and the content of the filler is 30-60 mass% based on the total mass of the film-like adhesive for the semiconductor.

SELECTED DRAWING: None

COPYRIGHT: (C)2023,JPO&INPIT

Description

TECHNICAL FIELD The present invention relates to a film-like adhesive for semiconductors, a method for manufacturing a semiconductor device, and a semiconductor device.

2. Description of the Related Art Conventionally, a wire bonding method using thin metal wires such as gold wires has been widely applied to connect semiconductor chips and substrates. On the other hand, in order to meet the demands for higher functionality, higher integration, and higher speed for semiconductor devices, a flip chip is a semiconductor chip or substrate that is directly connected to a substrate by forming conductive projections called bumps on the semiconductor chip or substrate. A 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 widely used in BGA (Ball Grid Array), CSP (Chip Size Package), etc., 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 connection portions (e.g., bumps and wiring) are formed on semiconductor chips to connect semiconductor chips (e.g., , see Patent Document 1).

In addition, for packages that are strongly required to be further miniaturized, thinned and highly functional, chip stack type packages, POP (Package On Package), TSV (Package On Package), and TSV ( Through-Silicon Via) and the like are beginning to spread widely. Such a stacking/multi-leveling technique arranges semiconductor chips and the like three-dimensionally, so that the package can be made smaller than the method of two-dimensionally arranging them. It is also effective in improving the performance of semiconductors, reducing noise, reducing the mounting area, and saving power.

JP 2008-294382 A

By the way, flip-chip packages are rapidly becoming more sophisticated and smaller. Along with the increase in functionality and miniaturization, the number of bumps is increasing, and the pitch and gap are becoming narrower. When the number of bumps is increased and the pitch and gap are narrowed, many voids such as trap voids that involve the space around the bumps and weld voids that occur behind the bumps due to resin flow during crimping may occur after mounting. be.

Further, in the flip chip package, from the viewpoint of improving productivity, it is required to shorten the compression bonding time during assembly of the flip chip package. In order to shorten the crimping time, it is necessary to crimp at a high temperature, but in such high-temperature crimping, it is difficult for the semiconductor film adhesive to harden sufficiently during crimping, so voids due to moisture and foaming components are formed. In addition, the minute voids caused by the entrapment described above may expand due to high temperatures, generating many fatal voids. When the flip chip package is used for a long period of time, peeling may occur inside the package starting from these voids. If the peeling inside the package becomes large, stress is applied to the connection portion and cracks are generated. Therefore, the peeling inside the package leads to connection failure of the package.

In addition, from the viewpoint of improving productivity, flip chip packages are required to be mounted at the wafer level when the flip chip packages are assembled. In this case, since many packages are mounted on one bottom wafer, stress is applied to each package, and the bottom wafer is greatly warped. If the bottom wafer warps, it becomes difficult to fix the bottom wafer to the suction table in the subsequent sealing process, making it difficult to seal the package.

For the above reasons, film adhesives for semiconductors are required to have properties capable of reducing voids and warping in addition to improving connection reliability.

Therefore, the present invention provides a semiconductor film that suppresses the warping of the bottom wafer even in wafer-level mounting, and can provide excellent connection reliability without voids after mounting even when the crimping time is shortened. The purpose is to provide an adhesive with a Another object of the present invention is to provide a semiconductor device using such a semiconductor film-like adhesive and a method for manufacturing the same.

The present inventors focused on the elastic modulus of the film-like adhesive after curing in order to reduce the warpage of a single-layer film-like adhesive. As a result, in single-layer film adhesives, increasing the amount of filler to improve the elastic modulus makes voids more likely to occur, while increasing the amount of hardening agent to reduce voids results in increased bonding. It became clear that 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 found that a film-like adhesive consists of a first adhesive layer and a second adhesive layer provided on the first adhesive layer. The present inventors have completed the present invention by finding that connection reliability, void reduction, and warpage reduction can be achieved at the same time by adjusting the elastic modulus after curing to a specific range after making a film adhesive.

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

According to the film-like adhesive for semiconductors, it is possible to suppress the warp of the bottom wafer even in mounting at the wafer level, and to obtain excellent connection reliability without voids after mounting even when the crimping time is shortened. can be done. In addition, according to the film-like adhesive for semiconductors, it is possible to shorten the pressure-bonding time, so that productivity can be improved. Further, according to the film-like adhesive for semiconductors, it is possible to easily increase the functionality and integration of the flip chip package.

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

According to the film-like adhesive for semiconductors, it is possible to suppress the warp of the bottom wafer even in mounting at the wafer level, and to obtain excellent connection reliability without voids after mounting even when the crimping time is shortened. can be done. In addition, according to the film-like adhesive for semiconductors, it is possible to shorten the pressure-bonding time, so that productivity can be improved. Further, according to the film-like adhesive for semiconductors, it is possible to easily increase the functionality and integration of the flip chip package.

At least one of the first adhesive layer and the second adhesive layer may be a thermosetting adhesive layer, or both may be thermosetting adhesive layers. In this case, shrinkage under an environment such as a temperature cycle test can be reduced, and even better connection reliability can be 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 is a tendency to use solder, copper, or the like as the metal of the connecting portion in place of gold or the like, which is resistant to corrosion, for the purpose of cost reduction. Furthermore, with regard to the surface treatment of wiring and bumps, there is a tendency to use solder, copper, etc., instead of gold, which is resistant to corrosion, for the purpose of cost reduction. In particular, flip-chip packages tend to use metals that are susceptible to corrosion and insulation deterioration due to ongoing cost reductions, which tends to reduce connection reliability (for example, insulation reliability). In addition, as described above, in order to suppress the generation of impurities, an anti-oxidation film may be formed by performing processing such as OSP processing. It may cause a decrease, etc. 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 in the connection can be removed, and there is a tendency to obtain even better connection reliability. be.

［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 using such a flux compound, even better connection reliability is likely to be obtained.

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

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 of the solder or the like is reduced and removed, so that even better connection reliability can be easily obtained.

One of the first adhesive layer and the second adhesive layer may be a thermosetting adhesive layer that does not contain a flux compound. In this case, since the adhesive layer that does not contain a flux compound is not easily affected by the flux compound, it is possible to express the property of being cured quickly and sufficiently after the connection parts come into contact with each other by this layer, and the crimping can be performed at high temperature. In addition, even if it is performed in a short time, it is possible to obtain better 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 containing no flux compound may contain a radically polymerizable compound and a thermal radical generator. In this case, since the curing speed is very excellent, voids are less likely to occur even when crimping is performed at high temperature for a short period of time, and more excellent connection reliability can be obtained.

The thermal radical generator may be a peroxide. In this case, even better handleability and storage stability are obtained, and thus even better connection reliability is likely to be obtained.

The radically polymerizable compound may be a (meth)acrylic compound. In this case, even better connection reliability is likely to be obtained.

The (meth)acrylic compound may have a fluorene skeleton. In this case, even better connection reliability is likely to be obtained.

When one of the first adhesive layer and the second adhesive layer is a thermosetting adhesive layer that does not contain a flux compound, the thermosetting adhesive layer that does not contain a flux compound may contain an epoxy resin. . In this case, even better connection reliability and storage stability are likely to be obtained.

The thermosetting adhesive layer containing no flux compound may further contain a latent curing agent. In this case, even better connection reliability is likely to be obtained.

The latent curing agent may be an imidazole curing agent. In this case, a flux activity that suppresses the formation of an oxide film on the connecting portion is obtained, so that even better connection reliability is likely to be obtained.

One aspect of the present invention is a semiconductor device in which respective connection portions of a semiconductor chip and a 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. , and relates to a method for manufacturing a semiconductor device, comprising a step of sealing at least a part of a connecting portion with the film-like adhesive for a semiconductor described above. According to this manufacturing method, warping of the bottom wafer is suppressed even in wafer-level mounting, and even when crimping time is shortened, there are no voids after mounting, and connection reliability (for example, insulation reliability) is excellent. You can get the device. That is, according to the manufacturing method described above, 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 respective connection portions of a semiconductor chip and a 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. The present invention relates to a semiconductor device in which at least a part of a connecting portion is sealed with a cured product of the film-like adhesive for a semiconductor described above. This semiconductor device has reduced warpage and voids, and exhibits excellent continuity reliability (for example, insulation reliability).

ADVANTAGE OF THE INVENTION According to the present invention, it is possible to suppress the warp of the bottom wafer even in wafer level mounting, and to obtain excellent connection reliability without voids after mounting even when the crimping time is shortened. It is possible to provide a type of adhesive. Further, according to the present invention, it is possible to provide a semiconductor device using such a semiconductor film-like adhesive and a method for manufacturing the same.

FIG. 1 is a schematic cross-sectional view showing one embodiment of the semiconductor device of the present invention. FIG. 2 is a schematic cross-sectional view showing another embodiment of the semiconductor device of the present invention. FIG. 3 is a schematic cross-sectional view showing another embodiment of the semiconductor device of the present invention. 4A to 4D are process cross-sectional views schematically showing an embodiment of the method for manufacturing a semiconductor device of the present invention.

As used herein, "(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, a numerical range indicated using "-" indicates a range including the numerical values described before and after "-" as the minimum and maximum values, respectively. Moreover, the upper limit value and the lower limit value described individually can be combined arbitrarily.

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will now be described in detail with reference to the drawings as the case may be.
In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant explanations are omitted. In addition, unless otherwise specified, positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings. Furthermore, the dimensional ratios of the drawings are not limited to the illustrated ratios.

<Film adhesive for semiconductors>
The film-like adhesive for semiconductors of the first embodiment comprises a first adhesive layer and a second adhesive layer provided on the first adhesive layer, and has an elastic modulus of 3.0 at 35° C. after curing. 0 to 5.0 GPa.

The film-like adhesive for semiconductors of the second embodiment is a film-like adhesive for semiconductors containing a filler, comprising a first adhesive layer and a second adhesive layer provided on the first adhesive layer. In addition, 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 (non-conductive film adhesive for semiconductors), and is used for semiconductor chips and wiring circuit boards. Used for sealing at least a part of the connection parts in a semiconductor device in which the connection parts are electrically connected to each other, or in a semiconductor device in which the connection parts of a plurality of semiconductor chips are electrically connected to each other be done.

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

Below, first, the film-like adhesive for semiconductors of the first embodiment will be described in detail.

(First embodiment)
In this embodiment, the first adhesive layer and the second adhesive layer are layers different from each other, and are formed of adhesive compositions different from each other. At least one of the first adhesive layer and the second adhesive layer is, for example, a thermosetting adhesive layer formed from a thermosetting resin composition (adhesive layer containing a thermosetting resin composition), It may be a photocurable adhesive layer (adhesive layer containing a photocurable resin composition) formed from a photocurable resin composition. At least one of the first adhesive layer and the second adhesive layer is a thermosetting resin from the viewpoint of reducing shrinkage in an environment such as a temperature cycle test and obtaining even better connection reliability. From the composition, it is preferably a thermosetting adhesive layer, 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 adhesive layers containing no flux compound. That is, the resin composition that constitutes 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"). It may be a resin composition that does not contain flux (hereinafter referred to as a “flux-free composition”).

In general, metal bonding is used for connection between connection parts from the viewpoint of sufficiently ensuring connection reliability (e.g., insulation reliability). Examples include solder, tin, gold, silver, copper, nickel, and the like. Conductive materials containing these multiple types of metals are also used. On the other hand, the surface of the metal used for the connecting part is oxidized to form an oxide film, and impurities such as oxides adhere to the surface, resulting in impurities on the connecting surface of the connecting part. Sometimes. If such impurities remain, the connection reliability (e.g., insulation reliability) between the semiconductor chip and the substrate or between two semiconductor chips is lowered, and the advantage of adopting the FC connection method described above is lost. There is concern that it will be lost. Therefore, as a method for suppressing the generation of these impurities, there is a method known as OSP (Organic Solderability Preservatives) treatment, etc., in which the connecting portion is coated with an anti-oxidation film. However, this anti-oxidation film may cause deterioration of solder wettability and connectivity during the connection process. In contrast, in the present 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), without OSP treatment, Better connection reliability can be obtained.

From the viewpoint of obtaining even better 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 contains a flux compound. It is preferably a non-containing adhesive layer (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 containing a thermosetting component and a flux compound. Thermosetting components include thermosetting resins and curing agents. Thermosetting resins include, for example, epoxy resins, phenol resins (except when contained as a curing agent), polyimide resins, and the like. Among these, the thermosetting resin is preferably an epoxy resin. Moreover, the film-like adhesive for semiconductors of the present embodiment may contain a polymer component having a weight average molecular weight of 10000 or more and a filler, if necessary.

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

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

From the viewpoint of suppressing the generation of volatile components by decomposition during connection at high temperature, the component (a) has a thermal weight loss rate of 5% or less at 250°C when the temperature at the time of connection is 250°C. 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 having a thermal weight loss rate of 5% or less at 300°C.

From the viewpoint of high heat resistance, the content of 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. is. From the viewpoint of film processability, the content of 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 these viewpoints, the content of 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]
Component (b) includes, for example, phenol resin curing agents, acid anhydride curing agents, amine curing agents, imidazole curing agents and phosphine curing agents. When the component (b) contains phenolic hydroxyl groups, acid anhydrides, amines or imidazoles, it exhibits a flux activity that suppresses the formation of an oxide film on the connection portion, thereby improving connection reliability and insulation reliability. can. An imidazole-based curing agent is more preferably used from the viewpoint that such an effect can be obtained more easily. Each curing agent will be described below.

(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 the molecule. , cresol naphthol formaldehyde polycondensate, triphenylmethane type polyfunctional phenolic resin and various polyfunctional phenolic resins can be used. These can be used singly or as a mixture of two or more.

The equivalent ratio of the phenolic resin curing agent to the component (a) (number of moles of phenolic hydroxyl groups in the phenolic resin curing agent/number of moles of epoxy groups in component (a)) provides good curability and adhesion. And from the viewpoint of storage stability, 0.3 to 1.5 is preferred, 0.4 to 1.0 is more preferred, and 0.5 to 1.0 is even more preferred. When the equivalent ratio is 0.3 or more, the curability tends to be improved and the adhesive strength tends to be improved. It tends to be kept low and insulation reliability improves.

(ii) Acid anhydride-based curing agent Acid anhydride-based curing agents include, for example, methylcyclohexanetetracarboxylic dianhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic dianhydride and ethylene glycol bis. Anhydro trimellitate can be used. These can be used singly or as a mixture of two or more.

The equivalent ratio of the acid anhydride curing agent to the component (a) (the number of moles of acid anhydride groups in the acid anhydride curing agent/the number of moles of epoxy groups in the component (a)) provides good curability. , from the viewpoint of adhesiveness and storage stability, preferably 0.3 to 1.5, more preferably 0.4 to 1.0, even more preferably 0.5 to 1.0. When the equivalent ratio is 0.3 or more, the curability tends to be improved and the adhesive strength tends to be improved. It tends to be kept low and insulation reliability improves.

(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 in the amine-based curing agent/the number of moles of epoxy groups in the component (a)) provides good curability, adhesion and storage. From the viewpoint of stability, it is preferably 0.3 to 1.5, more preferably 0.4 to 1.0, even more preferably 0.5 to 1.0. When the equivalent ratio is 0.3 or more, the curability tends to improve and the adhesive strength tends to improve, and when it is 1.5 or less, unreacted amine does not remain excessively, and insulation reliability improves. tend to

(iv) Imidazole curing agents Examples of imidazole curing agents 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 isocyanurate adduct, 2-phenylimidazole isocyanurate adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and epoxy resin and adducts of imidazoles. Among these, from the viewpoint of excellent curability, storage stability and connection reliability, 1-cyanoethyl-2-undecylimidazole, 1-cyano-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole trimeri 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 adducts, 2-phenylimidazole isocyanuric acid adducts, 2-phenyl-4,5-dihydroxymethylimidazole and 2-phenyl-4-methyl-5-hydroxymethylimidazole are preferred. These can be used alone or in combination of two or more. Moreover, it is good also as a latent hardening|curing agent which microencapsulated these.

The content of the imidazole curing agent is preferably 0.1 parts by mass or more per 100 parts by mass of component (a). Curability tends to improve when the content of the imidazole-based curing agent is 0.1 parts by mass or more. Also, the content of the imidazole-based curing agent is preferably 20 parts by mass or less, 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 during crimping can be ensured, and the flux-containing composition between the connecting portions can be sufficiently eliminated. As a result, it is suppressed that the flux-containing composition hardens in a state interposed between the solder and the connecting portion, so that connection failure tends to be less likely to occur. From these points of view, the content of the imidazole curing agent is preferably 0.1 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, per 100 parts by mass of component (a).

(v) Phosphine Curing Agent Examples of phosphine curing agents include triphenylphosphine, tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium tetra(4-methylphenyl)borate and tetraphenylphosphonium(4-fluorophenyl)borate. mentioned.

The content of the phosphine-based curing agent is preferably 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, per 100 parts by mass of component (a). When the content of the phosphine-based curing agent is 0.1 parts by mass or more, the curability tends to be improved. Therefore, connection failure tends to be less likely to occur.

The phenol resin-based curing agent, acid anhydride-based curing agent, and amine-based curing agent can be used singly or as a mixture of two or more. The imidazole-based curing agent and the phosphine-based curing agent may be used alone, or may be used together with a phenol 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), the flux-containing composition exhibits a flux activity to remove oxide films, thereby further improving connection reliability. can be done.

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

The flux compound preferably has a carboxyl group, more preferably two or more carboxyl groups, from the viewpoint of obtaining sufficient flux activity and more excellent connection reliability. Among these, compounds having two carboxyl groups are preferred. A compound having two carboxyl groups is less likely to volatilize at high temperatures during connection than a compound having one carboxyl group (monocarboxylic acid), and can further suppress the generation of voids. In addition, when a compound having two carboxyl groups is used, compared with the case of using a compound having three or more carboxyl groups, the increase in viscosity of the film-like adhesive for semiconductors during storage, connection work, etc. is further suppressed. It is possible to further improve the connection reliability of the semiconductor device.

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

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

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

In order to improve the reflow resistance, it is necessary to suppress the decrease in adhesive strength after moisture absorption at high temperature. Conventionally, carboxylic acids have been used as flux compounds, but the present inventors believe that conventional flux compounds cause a decrease in adhesive strength for the following reasons.

Normally, an epoxy resin reacts with a curing agent to proceed with the curing reaction, and at this time, carboxylic acid, which is a flux compound, is taken into the curing reaction. That is, an ester bond may be formed by reaction between the epoxy group of the epoxy resin and the carboxyl group of the flux compound. This ester bond is likely to be hydrolyzed or the like due to moisture absorption, etc., and the decomposition of this ester bond is considered to be one of the causes of the decrease in adhesive strength after moisture absorption.

On the other hand, among the compounds having a group represented by formula (1), compounds having a group in which R ¹ is an electron-donating group, i.e., compounds having a carboxyl group with an electron-donating group nearby When containing , sufficient flux activity is obtained by the carboxyl group, and even if the above-mentioned ester bond is formed, the electron-donating group increases the electron density of the ester bond and suppresses the decomposition of the ester bond. be done. In addition, since a substituent (electron-donating group) is present in the vicinity of the carboxyl group, steric hindrance suppresses the reaction between the carboxyl group and the epoxy resin, making it difficult to form an ester bond.

For these reasons, when a flux-containing composition further containing a compound having an electron-donating group for R ¹ among the compounds having the group represented by formula (1) is used, composition change due to moisture absorption or the like is less likely to occur. , excellent adhesion is maintained. In addition, it can be said that the above-mentioned effect is such that the curing reaction between the epoxy resin and the curing agent is less likely to be inhibited by the flux compound. It is also expected to have the effect of improving

When the electron-donating property of the electron-donating group becomes stronger, the effect of suppressing the decomposition of the ester bond described above tends to be more likely to be obtained. Further, when the steric hindrance of the electron-donating group is large, the effect of suppressing the above-described reaction between the carboxyl group and the epoxy resin is likely to be obtained. The electron-donating group preferably has well-balanced electron-donating properties and steric hindrance.

Electron donating groups include, for example, alkyl groups, hydroxyl groups, amino groups, alkoxy groups and alkylamino groups. The electron-donating group is preferably a group that hardly reacts with other components (for example, the epoxy resin of component (a)). 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. The greater the number of carbon atoms in the alkyl group, the greater the electron-donating ability and steric hindrance. An alkyl group having a number of carbon atoms within the above range has an excellent balance between electron-donating properties and steric hindrance.

In addition, the alkyl group may be linear or branched, 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 number of carbon atoms in the alkyl group is the number of carbon atoms in 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. The greater the number of carbon atoms in the alkoxy group, the greater the electron-donating ability and steric hindrance. An alkoxy group having the number of carbon atoms within the above range has an excellent balance between electron-donating properties and steric hindrance.

Moreover, 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 in the alkoxy group is equal to the number of carbon atoms in the main chain of the flux compound ( n+1) or less.

Alkylamino groups include monoalkylamino groups and dialkylamino groups. 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, 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, preferably linear.

A compound represented by the following formula (2) can be preferably used as the flux compound having two carboxyl groups. The compound represented by the following formula (2) can further improve the reflow resistance and connection reliability of the semiconductor device.

In 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. Multiple R ² may be the same or different.

R ¹ has the same definition as R ¹ in Formula (1). Also, the electron-donating properties represented by R ² are the same as the examples of electron-donating groups described above for R ¹ . For the same reason as explained for formula (1), R ¹ in formula (2) is preferably an electron-donating group.

n in formula (2) is preferably 1 or more. When n is 1 or more, compared to when n is 0, the flux compound is less likely to volatilize even at high temperatures during connection, and the generation of voids can be further suppressed. Also, n in formula (2) is preferably 15 or less, more preferably 11 or less, and may be 6 or less or 4 or less. When n is 15 or less, even better connection reliability can be obtained.

Moreover, as the flux compound, a compound represented by the following formula (3) is more preferable. The compound represented by the following formula (3) can further improve the reflow resistance and connection reliability of the semiconductor device.

In 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 formula (3) is preferably 10 or less, more preferably 5 or less, and even more preferably 3 or less. When m is 10 or less, even better connection reliability can be obtained.

In formula (3), R ¹ and R ² may be hydrogen atoms or electron donating groups. At least one of R ¹ and R ² is preferably an electron-donating group from the viewpoint of obtaining even better connection reliability. 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 further improved. In addition, 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, and the connection of the semiconductor device Reliability can be improved in some cases.

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

Examples of flux compounds include dicarboxylic acids selected from succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid and dodecanedioic acid, and two of these dicarboxylic acids. A compound substituted with an electron-donating group 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 even more preferably 130° C. or lower. Such a flux compound tends to exhibit sufficient flux activity before the curing reaction between the epoxy resin and the curing agent occurs. Therefore, according to the film-like adhesive for semiconductors using such a flux compound, it is possible to realize a semiconductor device with even more excellent connection reliability. Moreover, the melting point of the flux compound is preferably 25° C. or higher, more preferably 50° C. or higher. Moreover, the flux compound is preferably solid at room temperature (25° C.).

The melting point of the flux compound can be measured using a general melting point measuring device. A sample for measuring the melting point is required to be pulverized into a fine powder and to use a small amount to reduce the temperature deviation within the sample. A capillary tube closed at one end is often used as a container for a sample, but depending on the measurement device, the container is sandwiched between two microscope cover glasses. Also, if the temperature is rapidly raised, a temperature gradient will occur between the sample and the thermometer, resulting in measurement errors. desirable.

As described above, the sample for measuring the melting point is prepared as a fine powder, so the sample before melting is opaque due to diffuse 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 classic one is a double-tube thermometer fitted with a capillary tube filled with a sample and heated in a hot bath. A highly viscous liquid is used as the hot bath liquid for the purpose of attaching a capillary tube to a double-tube thermometer. Concentrated sulfuric acid or silicone oil is often used. Install. Further, as the melting point measuring apparatus, it is also possible to use a device that heats using a metal heat block and automatically determines the melting point while adjusting the heating while measuring the transmittance of light.

In this specification, the melting point of 150°C or lower means that the upper limit of the melting point is 150°C or lower, and the 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 component (c) is preferably 0.5 to 10% by mass, more preferably 0.5 to 5% by mass, based on the total mass of the flux-containing composition.

[(d) component: 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. A flux-containing composition containing component (d) is more excellent in heat resistance and film formability.

Examples of component (d) include phenoxy resins, polyimide resins, polyamide resins, polycarbodiimide resins, cyanate ester resins, acrylic resins, polyester resins, polyethylene resins, polyethersulfone resins, polyetherimide resins, polyvinyl acetal resins, and urethane resins. Resins and acrylic rubbers are mentioned. 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 (d) components can be used alone or as a mixture or copolymer of two or more. However, the (d) component does not include compounds corresponding to the (a) component and compounds corresponding to the (e) component.

The weight average molecular weight of component (d) is, for example, 10,000 or more, preferably 20,000 or more, and more preferably 30,000 or more. Such component (d) can further improve the heat resistance and film formability of the flux-containing composition.

The weight average molecular weight of component (d) is preferably 1,000,000 or less, more preferably 500,000 or less. Such component (d) can further improve the heat resistance of the flux-containing composition.

In the present specification, the weight average molecular weight means the weight average molecular weight 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 (manufactured by Hitachi, Ltd., trade name)
Pump: L6000 Pump (manufactured by Hitachi, Ltd., trade name)
Column: Gelpack GL-S300MDT-5 (2 in total) (manufactured by Hitachi Chemical Co., Ltd., trade name)
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 the component (d), the ratio C _a /C _d (mass ratio) of the content C _a of the component (a) to the content C _d of the component (d) is from 0.01 to It is preferably 5, more preferably 0.05 to 3, 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)), if necessary. Component (e) can control the viscosity of the flux-containing composition, the physical properties of the cured product of the flux-containing composition, and the like. Specifically, according to the component (e), it is possible to adjust the elastic modulus (e.g., elastic modulus at 35° C.) of the semiconductor film adhesive after curing, suppress the generation of voids during connection, and contain flux. It is possible to reduce the moisture absorption rate of the cured product of the composition.

Component (e) includes inorganic fillers (inorganic particles) and organic fillers (organic particles). Examples of inorganic fillers 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. At least one selected from the group consisting of silica, alumina and boron nitride is more preferred. The insulating inorganic filler may be a whisker. Examples of whiskers include aluminum borate, aluminum titanate, zinc oxide, calcium silicate, and boron nitride. Examples of organic fillers include resin fillers (resin particles). Examples of resin fillers include polyurethane and polyimide. Compared to inorganic fillers, resin fillers can impart flexibility at high temperatures such as 260°C, making them suitable for improving reflow resistance. effective. On the other hand, it is easy to adjust the elastic modulus to the desired range, and it is easy to adjust the viscosity of the film while suppressing warpage, and the occurrence of voids can be more sufficiently reduced. Inorganic fillers are preferably used from the viewpoint of obtaining.

The content of the inorganic filler makes it easy to adjust the elastic modulus to the desired range, suppresses warpage, and can sufficiently reduce the generation of voids, and furthermore, provides excellent connection reliability. From a 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 component (e). The component (e) may consist essentially of an inorganic filler. That is, the component (e) does not have to contain substantially any organic filler. "Substantially free" means that the content of the organic filler in component (e) is less than 0.5% by mass based on the total mass of component (e).

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

The content of the insulating filler makes it easy to adjust the elastic modulus to the desired range, suppresses warping, and can sufficiently reduce the occurrence of voids, and furthermore, provides excellent connection reliability. from the standpoint of being able to use the component (e), 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 an insulating filler. That is, the component (e) does not need to contain substantially any conductive filler. "Substantially free" means that the content of the conductive filler in component (e) is less than 0.5% by mass based on the total mass of component (e).

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

As the surface treatment, silane treatment with a silane compound such as an epoxysilane, aminosilane, or acrylsilane compound is preferable because of ease of surface treatment. As the surface treatment agent, at least one selected from the group consisting of glycidyl-based compounds, phenylamino-based compounds, and (meth)acrylic-based compounds is preferable from the viewpoint of excellent dispersibility, fluidity, and adhesive strength. . From the viewpoint of excellent storage stability, the surface treatment agent is preferably at least one selected from the group consisting of phenyl compounds and (meth)acrylic compounds.

The average particle diameter of the component (e) is preferably 1.5 μm or less from the viewpoint of preventing jamming during flip-chip bonding, and more preferably 1.0 μm or less from the viewpoint of excellent visibility (transparency).

The content of component (e) is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more, based on the total mass of the flux-containing composition. When the content of component (e) is 5% by mass or more, the amount of expansion against heat is small. In addition, since expansion of microvoids can be suppressed, connection reliability (especially connection reliability when used in an environment such as a temperature cycle test) is superior. The content of 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 connection reliability is excellent because the resin is sufficiently removed during thermocompression bonding. From these viewpoints, the content of component (e) is preferably 5 to 80% by mass, more preferably 10 to 70% by mass, more preferably 20 to 60% by mass, based on the total mass of the flux-containing composition. % by mass is more preferred.

[Other ingredients]
Additives such as an antioxidant, a silane coupling agent, a titanium coupling agent, a leveling agent, and an ion trapping agent may be added to the flux-containing composition. These can be used individually by 1 type or in combination of 2 or more types. The blending amounts of these additives may be appropriately adjusted so that the effects of each additive are exhibited.

(Flux-free composition)
The flux-free composition is, for example, a thermosetting resin composition. A flux-free composition is substantially free of flux compounds. “Substantially free” means that the flux compound content in the flux-free composition is less than 0.5% by mass based on the total mass of the flux-free composition.

The flux-free composition preferably has a curing reaction rate of 80% or more when kept at 200° C. for 5 seconds, from the viewpoint of significantly obtaining the effects of the present invention. Examples of such flux-free compositions include radical curing adhesives. In this embodiment, when one of the first adhesive layer and the second adhesive layer is an adhesive layer formed from a flux-containing composition and the other is an adhesive layer formed from a flux-free composition, In particular, the effects of the present invention can be obtained remarkably. Although the reason why such an adhesive can remarkably obtain the effects of the present invention is not clear, the present inventors speculate as follows.

That is, in film adhesives containing conventional flux compounds, since the flux component deactivates radicals, radical curing systems cannot be applied, and cationic curing systems using epoxy or the like are applied. I had a lot of things to do. In this curing system (reaction system), since curing progresses through a nucleophilic addition reaction, the curing rate is slow, and voids may occur after pressure bonding. In conventional film-like adhesives, it is presumed that these voids during mounting caused problems (for example, peeling of the semiconductor material at a reflow temperature of about 260° C., poor connection at the connecting portion, etc.). On the other hand, since the flux-free composition described above does not substantially contain a flux compound, the curing system can be a radical curing system, and a sufficient curing rate can be obtained. Therefore, by using the flux-free composition described above for the first adhesive layer or the second adhesive layer, voids are less likely to occur even when crimping is performed at high temperature for a short period of time. It is presumed that the effect will be remarkable. In addition, in the present embodiment, since a sufficient curing speed can be obtained, for example, even if solder is used in the connection part, the film adhesive can be cured in a temperature range lower than the solder melting temperature. can be made Therefore, it is possible to sufficiently suppress the occurrence of poor connection due to solder scattering and flow.

Hereinafter, the flux-free composition comprises a radically polymerizable compound (hereinafter sometimes referred to as "(A) component"), a thermal radical generator (hereinafter sometimes referred to as "(B) component"), and necessary Accordingly, an embodiment containing a polymer component (hereinafter sometimes referred to as "(C) component") and a filler (hereinafter sometimes referred to as "(D) component") will be described.

[(A) component: radically polymerizable compound]
Component (A) is a compound capable of undergoing a radical polymerization reaction when radicals are generated by heat, light, radiation, electrochemical action, or the like. Component (A) includes (meth)acrylic compounds, vinyl compounds, and the like. (A) Component (A) is preferably a (meth)acrylic compound 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 the molecule. Examples include bisphenol A type, bisphenol F type, naphthalene type, (Meth) acrylic compounds containing a phenol novolac type, cresol novolac type, phenol aralkyl type, biphenyl type, triphenylmethane type, dicyclopentadiene type, fluorene type, adamantane type or isocyanuric acid type skeleton; ) acrylic compounds (excluding (meth)acrylic compounds containing the above skeleton) and the like can be used. Examples of polyfunctional (meth)acrylic compounds include pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, and trimethylolpropane di(meth)acrylate. (A) component can be used individually by 1 type or in combination of 2 or more types.

From the viewpoint of excellent heat resistance, 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, and has a fluorene-type skeleton. is more preferable. Component (A) is more preferably a (meth)acrylate having any of the skeletons described above.

Component (A) is preferably solid at room temperature (25°C). A solid composition is less likely to generate voids than a liquid composition, and the viscosity (tack) of the flux-free composition before curing (B stage) is low, resulting in excellent handleability. Component (A) which is solid at room temperature (25° C.) includes (meth)acrylates having a bisphenol A skeleton, fluorene skeleton, adamantane skeleton, or isocyanuric acid skeleton.

The number of functional groups of the (meth)acrylic group in the component (A) is preferably 3 or less. When the number of functional groups is large, the curing network may proceed 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 period of time tends to proceed sufficiently, so that it is easy to suppress a decrease in the curing reaction rate.

The molecular weight of component (A) is preferably less than 2,000, more preferably 1,000 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 component (A) is 10% by mass or more, based on the total mass of the flux-free composition, from the viewpoint of suppressing a decrease in the curing component and facilitating sufficient control of the resin flow after curing. is preferred, and 15% by mass or more is more preferred. The content of component (A) is 50 based on the total mass of the flux-free composition, from the viewpoint that the cured product is suppressed from becoming too hard and the package warpage tends to be suppressed from becoming large. % by mass or less is preferable, 45% by mass or less is more preferable, and 40% by mass or less is even more preferable. From these viewpoints, the content of component (A) is preferably 10 to 50% by mass, more preferably 10 to 45% by mass, more preferably 15 to 40% by mass, based on the total mass of the flux-free composition. preferable.

The content of the component (A) is 0.01 parts by mass or more per 1 part by mass of the component (C) from the viewpoint of suppressing deterioration of the curability and easily suppressing the deterioration of the adhesive strength. It is preferably 0.05 parts by mass or more, and even 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 per 1 part by mass of the component (C), from the viewpoint of easily suppressing deterioration in film formability. From these viewpoints, the content of component (A) is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, more preferably 0.1 to 1 part by mass, relative to 1 part by mass of component (C). 5 parts by mass is more preferable.

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

Thermal radical generators include azo compounds and peroxides (organic peroxides, etc.). As the thermal radical generator, peroxides are preferred, and organic peroxides are more preferred. In this case, a radical reaction does not proceed in the step of drying the solvent in forming the film, and the handling and storage stability are excellent. Therefore, when a peroxide is used as the thermal radical generator, even better connection reliability is likely to be obtained. Examples of organic peroxides include ketone peroxides, peroxyketals, hydroperoxides, dialkyl peroxides, diacyl peroxides, peroxydicarbonates and peroxyesters. From the viewpoint of excellent storage stability, the organic peroxide is preferably at least one selected from the group consisting of hydroperoxides, dialkyl peroxides and peroxyesters. Furthermore, the organic peroxide is preferably at least one selected from the group consisting of hydroperoxides and dialkyl peroxides from the viewpoint of excellent heat resistance. Dialkyl peroxides include dicumyl peroxide, di-tert-butyl peroxide and the like.

The content of the component (B) is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, relative to 100 parts by mass of the component (A), from the viewpoint that curing proceeds sufficiently. The content of component (B) is preferably 10 parts by mass or less, more preferably 5 parts by mass or less per 100 parts by mass of component (A). When the upper limit of the content of the component (B) is within the above range, the rapid progress of curing and the suppression of an increase in the number of reaction sites are suppressed, thereby shortening the molecular chain and reducing the number of unreacted groups. 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 deterioration in reliability. From these points of view, the content of component (B) is preferably 0.5 to 10 parts by mass, more preferably 1 to 5 parts by mass, per 100 parts by mass of component (A).

[(C) component: polymer component]
The flux-free composition can further contain polymeric components. Component (C) includes epoxy resin, phenoxy resin, polyimide resin, polyamide resin, polycarbodiimide resin, cyanate ester resin, (meth)acrylic resin, polyester resin, polyethylene resin, polyethersulfone resin, polyetherimide resin, and polyvinyl acetal. resins, urethane resins, acrylic rubbers, etc. Among them, 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-forming properties. 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. Component (C) may be used singly or as a mixture or copolymer of two or more. However, the (C) component does not include the compound corresponding to the (A) component and the compound corresponding to the (D) component.

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 semiconductor film adhesive to a substrate or chip. preferable. Within these ranges, bumps formed on a semiconductor chip, electrodes formed on a substrate, or irregularities such as wiring patterns can be easily embedded with a semiconductor film-like adhesive (hardening reaction starts). It is easy to suppress the formation of voids), and it is easy to suppress the generation of voids due to the remaining air bubbles. The above Tg is measured using a DSC (manufactured by PerkinElmer Japan Co., Ltd., product name: DSC-7 type) under the conditions of a sample amount of 10 mg, a temperature increase rate of 10 ° C./min, and a measurement atmosphere of air. is the Tg of

The weight-average molecular weight of 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 exhibit good film formability by itself. When the weight average molecular weight is 10,000 or more, it is easy to suppress deterioration of film formability.

[(D) component: filler]
The flux-free composition contains a filler in order to control the viscosity or the physical properties of the cured product, and to further suppress the generation of voids or moisture absorption when connecting a semiconductor chip and a substrate or between semiconductor chips. It may be contained further. As the component (D), the same filler as the component (e) in the flux-containing composition can be used. Examples of preferred fillers are the same. 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 also the same.

The content of component (D) is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more, based on the total mass of the flux-free composition. The content of component (D) may be 30% by mass or more or 40% by mass or more. When the content of component (D) is 5% by mass or more, the amount of expansion against heat is small. In addition, since expansion of microvoids can be suppressed, connection reliability (especially connection reliability when used in an environment such as a temperature cycle test) is superior. The content of component (D) is preferably 90% by mass or less, more preferably 80% by mass or less, still more preferably 70% by mass or less, and even more preferably 60% by mass or less, based on the total mass of the flux-free composition. more preferred. When the content of the component (D) is 90% by mass or less, the connection reliability is excellent because the resin is sufficiently removed during thermocompression bonding. From these viewpoints, the content of component (D) is preferably 5 to 90% by mass, more preferably 5 to 80% by mass, more preferably 10 to 70% by mass, based on the total mass of the flux-free composition. Preferably, 20 to 60 mass % is even more preferred. The content of component (D) may be 30 to 90% by mass or 40 to 80% by mass.

[Other ingredients]
The flux-free composition may contain a polymerizable compound other than the radically polymerizable compound (for example, a cationic polymerizable compound and an anionically polymerizable compound). The flux-free composition may also contain other components similar to those of the flux-containing composition. These can be used individually by 1 type or in combination of 2 or more types. The blending amounts of these additives may be appropriately adjusted so that the effects of each additive are exhibited.

An embodiment in which the flux-free composition contains a radically polymerizable compound, a thermal radical generator, and, if necessary, a polymer component and a filler has been described above. It is not limited to the above aspect.

For example, the flux-free composition comprises the above-described component (a) (epoxy resin), component (b) (curing agent), and optionally component (d) (polymer having a weight average molecular weight of 10,000 or more). component) and (e) component (filler). Examples of usable components (a), (b), (d) and (e) and preferred compounds when the flux-free composition is a resin composition containing these components are The same is true for flux-containing compositions. For example, the flux-free composition preferably contains an imidazole curing agent as a curing agent.

From the viewpoint of high heat resistance, the content of 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's it. From the viewpoint of film processability, the content of 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.

The content of the component (b) (for example, the content of the imidazole curing agent) is preferably 0.1 parts by mass or more with respect to 100 parts by mass of the component (a) from the viewpoint of improving curability. Moreover, the content of the component (b) is preferably 20 parts by mass or less, more preferably 10 parts by mass, from the viewpoint of suppressing poor connection.

The content of component (d) is such that the ratio C _a2 /C _d2 (mass ratio) of the content C _a2 of component (a) to the content C _d2 of 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 adhesive strength 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 component (e) is 5 based on the total mass of the flux-free composition, from the viewpoint of better connection reliability (especially connection reliability when used in an environment such as a temperature cycle test). % by mass or more is preferable, 10% by mass or more is more preferable, and 20% by mass or more is even more preferable. The content of the component (e) is preferably 80% by mass or less, preferably 70% by mass, based on the total mass of the flux-free composition, from the viewpoint of sufficiently removing the resin during thermocompression bonding and improving the connection reliability. % by mass or less is more preferable, and 60% by mass or less is even more preferable.

The curing reaction rate when the flux-free composition is held at 200° C. for 5 seconds is preferably 80% or more, more preferably 90% or more. If the curing reaction rate at 200° C. (below the solder melting temperature)/5 seconds is 80% or more, it is easy to suppress the solder from scattering and flowing at the time of connection (above the solder melting temperature) and reducing the connection reliability. The curing reaction rate was measured by placing 10 mg of the flux-free composition (uncured flux-free layer) in an aluminum pan, and measuring the calorific value using a DSC (manufactured by PerkinElmer Japan Co., Ltd., trade name: DSC-7). can be obtained by measuring Specifically, a measurement sample containing 10 mg of the flux-free composition (uncured flux-free layer) placed in an aluminum pan is placed on a hot plate heated to 200° C. After 5 seconds, the measurement sample is removed from the hot plate. remove the A measurement sample after heat treatment and an untreated measurement sample are each measured by DSC. From the obtained calorific value, the curing reaction rate is calculated by the following formula.
Curing reaction rate (%) = (1-[calorific value of measurement sample after heat treatment]/[calorific value of untreated measurement sample]) × 100

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

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

The film adhesive for semiconductors 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. of 3.0 to 5.0 GPa after curing. . The elastic modulus of the film-like adhesive for semiconductors is determined, for example, by the types and compounding ratios of the components that constitute the film-like adhesive for semiconductors (for example, the components that constitute the first adhesive layer and the components that constitute 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. In addition, the elastic modulus of the film-like 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 effect of the present invention becomes remarkable. The elastic modulus may be 4.7 GPa or less, or 4.4 GPa or less from the viewpoint that the effect of the present invention becomes 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.

From the viewpoint that the effect of the present invention becomes remarkable, the content of the filler in 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. or more, and may be 60% by mass or less, 50% by mass or less, or 45% by mass or less.

The content of the filler in one of the first adhesive layer and the second adhesive layer is 25 mass based on the total mass of the film-like adhesive for semiconductor from the viewpoint that the effect of the present invention becomes remarkable. % or more, 35 mass % or more, or 45 mass % or more, and may be 60 mass % or less, 55 mass % or less, or 50 mass % or less. In addition, from the viewpoint that the effect of the present invention becomes remarkable, the content of the filler in the other layer of the first adhesive layer and the second adhesive layer is based on the total mass of the film-like adhesive for semiconductors. 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.

With regard to the thickness of the film-like adhesive for semiconductors, when the sum of the heights of the connection portions is x and the total thickness of the film-like adhesive for semiconductors is y, the relationship between x and y is From the viewpoint of connectivity and adhesive filling, 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. It's okay.

The thickness of the second adhesive layer (eg, 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, an adhesive layer containing no flux compound) to the thickness of the first adhesive layer (for example, an adhesive layer containing a flux compound) (thickness of the second adhesive layer/second 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-like adhesive for semiconductors may further comprise layers other than the first adhesive layer and the second adhesive layer, but preferably consists of only the first adhesive layer and the second adhesive layer. . In addition, the film-like adhesive for semiconductors of the present embodiment is formed on the surface of the first adhesive layer opposite to the second adhesive layer and/or on the surface of the second adhesive layer on the side opposite to the first adhesive layer. A substrate film and/or a protective film may be provided on the opposite side.

In the film adhesive for semiconductors, the first adhesive layer and the second adhesive layer may be adjacent to each other. In this case, the first adhesive layer and the second adhesive layer are preferably formed so as not to separate 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 does not have to be 3.0 to 5.0 GPa. The details of the semiconductor film-like adhesive of the second embodiment are the same as those of the first embodiment, except for differences in the content of the flux compound, the difference in filler content between the first adhesive layer and the second adhesive layer, and the like. The form may be the same as that of the film adhesive for semiconductors.

<Method for producing film adhesive for semiconductor>
For the semiconductor film adhesive of the present embodiment, 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-like adhesive having one adhesive layer and a second film-like adhesive having a second adhesive layer.

A film-like adhesive (first film-like adhesive and/or second film-like adhesive) provided with an adhesive layer (adhesive layer containing a flux-containing composition) formed from a flux-containing composition as an adhesive layer. In the preparing step, for example, first, components (a), components (b) and (c), and other components such as components (d) and (e) that are added as necessary are added to an organic solvent. The resin varnish (coating varnish) is prepared by adding it to the inside and dissolving or dispersing it by stirring, mixing, kneading, or the like. Thereafter, a resin varnish is applied onto the substrate film that has been subjected to release treatment using a knife coater, roll coater, applicator, or the like, and then the organic solvent is reduced by heating to form a flux-containing composition on the substrate film. An adhesive layer can be formed comprising:

The organic solvent used for the preparation of the resin varnish is preferably one having properties capable of uniformly dissolving or dispersing each component. Toluene, benzene, xylene, methyl ethyl ketone, tetrahydrofuran, ethyl cellosolve, ethyl cellosolve acetate, butyl cellosolve, dioxane, cyclohexanone, and ethyl acetate. These organic solvents can be used alone or in combination of two or more. Stirring, mixing and kneading during the preparation of the resin varnish can be performed using, for example, a stirrer, a kneader, a three-roll mill, a ball mill, a bead mill, or a homodisper.

The base film is not particularly limited as long as it has heat resistance that can withstand the heating conditions when the organic solvent is volatilized. Polyolefin film such as polypropylene film, polymethylpentene film, polyethylene terephthalate film, polyethylene naphthalate. Polyester films such as films, polyimide films and polyetherimide films can be exemplified. The base film is not limited to a single layer made of these films, and may be a multi-layered film made of two or more materials.

The drying conditions for volatilizing the organic solvent from the resin varnish applied to the base film are preferably conditions under which the organic solvent is sufficiently volatilized, specifically, 50 to 200° C. for 0.1 to 90 minutes. is preferably heated. The organic solvent is preferably removed to 1.5% by mass or less with respect to the total amount of the first film-like adhesive, as long as it does not affect voids after mounting or viscosity adjustment.

A film-like adhesive (a first film-like adhesive and/or a second film-like adhesive ), for example, (A) component and (B) component, and other components such as (C) component added as necessary, or (a) component and (b) component, and necessary Depending on the above, an adhesive layer containing the flux-free composition can be formed on the substrate film in the same manner as for the first adhesive layer, except that other components such as component (d) are used.

Examples of methods for bonding the first film-like adhesive and the second film-like adhesive include methods such as heat press, roll lamination, and vacuum lamination. Lamination may be performed under heating conditions of, for example, 30 to 120°C.

The film-like adhesive for semiconductors of the present embodiment is, for example, after forming one of the first adhesive layer and 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 or 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 method for forming the first adhesive layer and the second adhesive layer in the production of the film-like adhesive with substrate described above.

<Semiconductor device>
The semiconductor device of this embodiment will be described below with reference to FIGS. FIG. 1 is a schematic cross-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 wirings 15 arranged on surfaces of the semiconductor chip 10 and the substrate 20 facing each other. , connection bumps 30 for connecting the wirings 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) that fills the gaps between the semiconductor chip 10 and the substrate 20 without any gaps. and a sealing portion 40 made of a cured product of . The semiconductor chip 10 and substrate 20 are flip-chip connected by wiring 15 and connection bumps 30 . The wiring 15 and the connection bumps 30 are sealed with a cured adhesive and are isolated from the external environment. The sealing portion 40 has an upper portion 40a containing a cured product of a flux-containing composition or a flux-free composition, and a lower portion 40b containing a cured product of a flux-containing composition or a flux-free composition. . The upper portion 40a and the lower portion 40b contain cured products of different thermosetting resin compositions.

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

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

The semiconductor chip 10 is not particularly limited, and elemental 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, and the surface of an insulating substrate mainly composed of glass epoxy, polyimide, polyester, ceramic, epoxy, bismaleimide triazine, etc. is etched to remove unnecessary portions of the metal film. A circuit board having wiring (wiring pattern) 15 formed by removal, a circuit board having wiring 15 formed by metal plating or the like on the surface of the insulating substrate, and wiring by printing a conductive material on the surface of the insulating substrate. A circuit board or the like on which 15 is formed can be used.

The connection parts such as the wiring 15 and the bumps 32 are mainly composed of gold, silver, copper, solder (main components are, for example, tin-silver, tin-lead, tin-bismuth, tin-copper, tin-silver-copper, etc.). ), nickel, tin, lead, etc., and may contain multiple metals.

Among the above metals, gold, silver, and copper are preferable, and silver and copper are more preferable, from the viewpoint of providing a package having excellent electrical conductivity and thermal conductivity at the connection portion. From the viewpoint of a package with reduced cost, silver, copper and solder, which are inexpensive materials, are preferred, copper and solder are more preferred, and solder is even more preferred. If an oxide film is formed on the surface of the metal at room temperature, the productivity may decrease and the cost may increase. Therefore, from the viewpoint of suppressing the formation of the oxide film, gold, silver, copper and solder 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, etc. are mainly applied to the surfaces of the wiring 15 and the bumps 32 . The component metal layer may be formed by, for example, plating. This metal layer may consist of a single component only, or may consist of a plurality of components. Moreover, the metal layer may have a structure in which a single layer or a plurality of metal layers are laminated.

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

As a method for stacking a plurality of semiconductor devices, for example, TSV (Through-Silicon Via) technology can be cited as shown in FIG. FIG. 3 is a schematic cross-sectional view showing another embodiment of the semiconductor device of the present invention, which is a semiconductor device using 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, whereby the semiconductor chip 10 and the interposer 50 are flip-chip connected. ing. The space between the semiconductor chip 10 and the interposer 50 is filled with a cured adhesive (for example, a flux-containing composition and a flux-free composition) to form a sealing portion 40 . On the surface of the semiconductor chip 10 opposite to the interposer 50 , the semiconductor chips 10 are repeatedly stacked via the wirings 15 , the connection bumps 30 and the sealing portion 40 . The wirings 15 on the pattern surfaces on the front and back of the semiconductor chip 10 are connected to each other by through-electrodes 34 filled in holes penetrating through the inside of the semiconductor chip 10 . Copper, aluminum, or the like can be used as the material of the through electrode 34 .

Such TSV technology makes it possible to acquire signals even from the back surface of a semiconductor chip, which is normally not used. Furthermore, since the through electrodes 34 are vertically passed through the semiconductor chips 10, the distance between the opposing semiconductor chips 10 and the distance between the semiconductor chips 10 and the interposer 50 can be shortened to enable flexible connection. The semiconductor film adhesive of the present embodiment can be applied as a semiconductor film adhesive between opposing semiconductor chips 10 and between the semiconductor chip 10 and the interposer 50 in such TSV technology.

Also, in a bump formation method with a high degree of freedom such as area bump chip technology, a semiconductor chip can be directly mounted on a mother board as it is without an interposer. The film-like adhesive for semiconductors of this embodiment can also be applied when such a semiconductor chip is directly mounted on a motherboard. The film-like adhesive for semiconductors of this embodiment can also be applied to seal a gap between two printed circuit boards when laminating two printed circuit boards.

<Method for manufacturing a semiconductor device>
Regarding the method of manufacturing a semiconductor device according to the present embodiment, referring to FIG. A case where the adhesive layer is an adhesive layer will be described as an example. However, even if the thermosetting resin compositions forming the first adhesive layer and the second adhesive layer are different, the semiconductor device can be manufactured in the same manner.

FIGS. 4A, 4B, and 4C are diagrams schematically showing one embodiment of the method for manufacturing a semiconductor device of the present invention, and FIGS. shows a cross section of

First, as shown in FIG. 4A, a solder resist 60 having openings at positions where connection bumps 30 are to be formed is formed on a substrate 20 having wirings 15 . This solder resist 60 does not necessarily have 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 package solder resist ink. Specific examples of commercially available solder resist inks for packages include the SR series (manufactured by Hitachi Chemical Co., Ltd., trade name) and the PSR4000-AUS series (manufactured by Taiyo Ink Mfg. Co., Ltd., trade name).

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 of the second adhesive layer 41b containing the flux-free composition becomes the substrate 20 side. As shown, the semiconductor film adhesive (hereinafter sometimes referred to as "film adhesive") 41 of the present embodiment is applied. The film-like adhesive 41 can be applied by hot pressing, roll lamination, vacuum lamination, or the like. The supply area and thickness of the film adhesive 41 are appropriately set according to the sizes of the semiconductor chip 10 and the substrate 20, the height of the connection bumps 30, and the like. The film-like adhesive 41 may be applied so that the first adhesive layer 41a side containing the flux-containing composition faces the substrate 20 side.

After the film adhesive 41 is attached to the substrate 20 as described above, the wirings 15 of the semiconductor chip 10 and the connection bumps 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, thereby connecting the semiconductor chip 10 and the substrate 20 together as shown in FIG. The gap between the semiconductor chip 10 and the substrate 20 is sealed and filled with the sealing portion 40 made of the cured adhesive 41 . As described above, the semiconductor device 600 is obtained.

The crimping time may be, for example, 5 seconds or less. In this embodiment, since the film-like adhesive 41 of this embodiment described above 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 manufacturing method of the semiconductor device of the present embodiment, the connection bumps 30 are melted by performing a heat treatment in a reflow furnace and temporarily fixed after alignment (a state in which the semiconductor film-like adhesive is interposed). Chip 10 and substrate 20 may be connected. At the stage of temporary fixation, it is not always necessary to form a metal joint. Therefore, compared to the above-mentioned method of crimping while heating, crimping with a lower load, a shorter time, and a lower temperature is sufficient, which improves productivity and connection. It is possible to suppress the deterioration of the part.

Further, after connecting the semiconductor chip 10 and the substrate 20, 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 curing of the film-like adhesive proceeds, more preferably a temperature at which it is completely cured. The heating temperature and heating time are appropriately set.

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

From the viewpoint of improving productivity, a semiconductor film adhesive is supplied to a semiconductor wafer in which a plurality of semiconductor chips 10 are connected, and then diced into individual pieces, thereby forming a semiconductor film adhesive on the semiconductor chips 10. An agent-fed structure may be obtained. The semiconductor film-like adhesive may be supplied so as to embed the wiring, bumps, etc. on the semiconductor chip 10 by a bonding method such as hot pressing, roll lamination, or vacuum lamination. In this case, since the amount of resin supplied is constant, the productivity is improved, and the generation of voids due to insufficient filling and the deterioration of dicing performance can be suppressed.

The connection load is set in consideration of the variation in the number and height of the connection bumps 30, the deformation amount of the connection bumps 30 due to pressure, or the wiring receiving the bumps of the connection portion. As for the connection temperature, it is preferable that the temperature of the connection portion is equal to or higher than the melting point of the connection bump 30, but the temperature may be any temperature at which metal bonding of each connection portion (bump and wiring) is formed. If the connection bumps 30 are solder bumps, a temperature of about 240° C. or higher is preferred.

The connection time at the time of connection varies depending on the constituent metal of the connection portion, but from the viewpoint of improving productivity, the shorter the connection time, the better. When the connection bumps 30 are solder bumps, 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.

The film-like adhesive for semiconductors of the present embodiment exhibits excellent reflow resistance and connection reliability even in the flip-chip connection portions of the various package structures described above.

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

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the examples.

<Preparation of single layer films A and B>
The compounds used to prepare Single Layer Film A with a flux-containing layer and Single Layer Film B with a non-flux-containing 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 (manufactured by Mitsubishi Chemical Corporation, trade name: jERYL983U)
(b) Curing agent 2,4-diamino-6-[2′-methylimidazolyl-(1′)]-ethyl-s-triazine isocyanurate adduct (manufactured by Shikoku Kasei Kogyo Co., Ltd., trade name: 2MAOK-PW )
(c) Flux compound/glutaric acid (manufactured by Tokyo Kasei Co., Ltd., melting point about 98°C)
・ 2-Methylglutaric acid (manufactured by Sigma-Aldrich, melting point about 78 ° C.)
(d) Polymer component/phenoxy resin (manufactured by Tohto Kasei Co., Ltd., trade name: ZX1356-2, Tg: about 71°C, weight average molecular weight Mw: about 63000)
(e) Filler/silica filler (manufactured by Admatechs Co., Ltd., trade name: SE2050, average particle size: 0.5 μm)
・ Epoxysilane surface treatment filler (manufactured by Admatechs Co., Ltd., trade name: SE2050-SEJ, average particle size: 0.5 μm)
・ Methacrylic 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 Co., Ltd., EXL-2655: core-shell type organic fine particles)

In the preparation of single-layer film A, the blending amounts (unit: parts by mass) shown in Table 1 of epoxy resin, curing agent, flux compound, polymer component and filler were added to the NV value ([mass of paint after drying]/[ It was added to the organic solvent (methyl ethyl ketone) so that the weight of the paint before drying]×100) became 50%. After that, Φ1.0 mm beads and Φ2.0 mm beads are 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 Co., Ltd., planetary pulverization) The mixture was stirred for 30 minutes with machine P-7). After stirring, the beads were removed by filtration to prepare a coating varnish. In the production of the single layer film B, a coating varnish was produced in the same manner as in the case of the single layer film A except that no flux compound was used.

The obtained coating varnish is coated on a substrate film (trade name: Purex A54, manufactured by Teijin DuPont Films Japan Limited) with a small precision coating device (Radoi Seiki), and a clean oven (ESPEC Co., Ltd.) product) and dried (80 ° C./10 min) to obtain single-layer films (A-1), (A-2), (A-3), (A-4), (B-1) and (BB-2) was obtained. Both the thickness of the flux-containing layer in single-layer film A and the thickness of the flux-free layer in single-layer film B were set to 20 μm.

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

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

(C) Polymer component Acrylic resin (manufactured by Hitachi Chemical Co., Ltd., product name: KH-CT-865, weight average molecular weight Mw: 100000, Tg: 10 ° C.)

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

A (meth)acrylic compound, a polymer component and a filler in the blending amounts (unit: parts by mass) shown in Table 1 were added to an organic solvent (methyl ethyl ketone) so that the NV value was 50%. After that, Φ1.0 mm beads and Φ2.0 mm beads are added in the same mass as the solid content ((meth)acrylic compound, polymer component and filler), and a bead mill (manufactured by Fritsch Japan Co., Ltd., planetary pulverizer P -7) and stirred for 30 minutes. After stirring, the beads were removed by filtration. Next, a thermal radical generator was added to the resulting mixture, and the mixture was stirred and mixed to prepare a coating varnish.

The resulting coating varnish is applied onto a substrate film (manufactured by Teijin DuPont Films Limited, product name: Purex A54) with a small precision coating device (manufactured by Kadoiseiki Co., Ltd.), and then in a clean oven ( ESPEC Co., Ltd.) and dried (80° C./10 min) 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.

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

<Evaluation>
Elastic modulus measurement, chip warpage evaluation, initial connectivity evaluation, and void evaluation for the film-like adhesives obtained in Examples and Comparative Examples and semiconductor devices fabricated using the film-like adhesives by the methods shown below. , and a temperature cycle test evaluation. Table 1 shows the results.

(Elastic modulus measurement)
The film adhesive obtained in Examples or Comparative Examples was cut into a predetermined size (length 40 mm x width 4.0 mm x thickness 0.06 mm) and cured in a clean oven (manufactured by ESPEC Co., Ltd.). A test sample was obtained. The curing conditions were 240° C. and 1 hour.

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

(Chip warpage evaluation)
A film-like adhesive obtained in Examples or Comparative Examples is coated with a silicon chip (length 10 mm x width 10 mm x thickness 0.05 mm, oxide coating). Next, the sample laminated with the film adhesive was cured in a clean oven (manufactured by ESPEC Co., Ltd.) to obtain a test sample. The curing conditions were 240° C. and 1 hour.

Moiré measurement was performed using a 3D heating surface profile measuring device Thermoray PS200S (manufactured by Akrometrix), and the result of warpage was defined as "A" for less than 130 µm, "B" for less than 130 µm or more and less than 150 µm, and 150 µm or more. The tip warpage was evaluated with "C". Specifically, the above-described test sample was placed under glass with vertical stripes, light was applied from an oblique direction, interference fringes were measured with a camera, and analysis was performed to measure the warpage of the test sample.

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

The connection resistance value of the obtained semiconductor device was measured using a multimeter (manufactured by Advantest Co., Ltd., trade name: R6871E) to evaluate the initial conduction after mounting. If the connection resistance value is 10.0 Ω or more and 13.5 Ω or less, the connectivity is “A” (good), and if the connection resistance value is 13.5 Ω or more and 20 Ω or less, the connectivity is “B” (bad). All the cases where the resistance value was greater than 20Ω, the connection resistance value was less than 10Ω, and the resistance value was not displayed due to poor connection were evaluated as "C" (bad).

(void evaluation)
For the semiconductor device manufactured by the above method, an external image is taken with an ultrasonic imaging diagnostic device (trade name: Insight-300, manufactured by Insight Corporation), and a scanner GT-9300UF (manufactured by Seiko Epson Corporation, trade name) is used. An image of the adhesive part on the chip (the part consisting of the cured film-like adhesive for semiconductors) is captured, and the image processing software Adobe Photoshop (registered trademark) is used to identify the void part through color correction and two-tone conversion. , and the ratio of the void portion was calculated from the histogram. Taking the area of the adhesive part on the chip as 100%, the case where the void generation rate is 5% or less is "A", the case of more than 5% and 10% or less is "B", and the case of more than 10% is " It was evaluated as "C".

(Temperature cycle test evaluation (TCT resistance evaluation))
The semiconductor device produced by the above method was molded using a sealing material (manufactured by Hitachi Chemical Co., Ltd., trade name: CEL9750ZHF10) under conditions of 180° C., 6.75 MPa, and 90 seconds. After-curing was then performed in a clean oven (manufactured by ESPEC Co., Ltd.) at 175° C. for 5 hours to obtain a package. Next, this package is connected to a thermal cycle tester (manufactured by Kusumoto Kasei Co., Ltd., product name: THERMAL SHOCK CHAMBER NT1200), and a 1 mA current is applied, 25 ° C. for 2 minutes / -55 ° C. for 15 minutes / 25 ° C. for 2 minutes / 125. C. 15 minutes/25.degree. C. 2 minutes as one cycle, and the change in connection resistance was evaluated after repeating 1000 cycles. If there is no significant change after 1000 cycles compared to the initial resistance value waveform (no difference or a difference of less than 1 Ω), "A", If a difference of 1 Ω or more occurs, "B""

It was confirmed that the film-like adhesives for semiconductors of 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 semiconductors Film adhesive 50 Interposer 60 Solder resist 100, 200, 300, 400, 500, 600 Semiconductor device.

Claims (10)

A film adhesive for a semiconductor containing a filler,
A first adhesive layer and a second adhesive layer provided on the first adhesive layer,
one of the first adhesive layer and the second adhesive layer is a thermosetting adhesive layer containing a flux compound;
the other of the first adhesive layer and the second adhesive layer is a thermosetting adhesive layer that does not contain a flux compound;
The thermosetting adhesive layer containing no flux compound is composed of a radical curing adhesive,
A film adhesive for semiconductor, wherein the content of the filler is 30 to 60% by mass based on the total mass of the film adhesive for semiconductor. The film-like adhesive for semiconductors according to claim 1, wherein the flux compound has a carboxyl group. 2. The film-like adhesive for semiconductors according to claim 1, wherein said flux compound has two or more carboxyl groups. The film-like adhesive for semiconductors according to claim 1, wherein the flux compound is a compound represented by the following formula (2).

[In Formula (2), R ¹ and R ² each independently represent a hydrogen atom or an electron-donating group, and n represents an integer of 0 or 1 or more. Multiple R ² may be the same or different. ] The film adhesive for a semiconductor according to any one of claims 1 to 4, wherein the flux compound has a melting point of 150°C or less. The film adhesive for semiconductor according to any one of claims 1 to 5, wherein the thermosetting adhesive layer containing no flux compound contains a (meth)acrylic compound. 7. The film-like adhesive for semiconductors according to claim 6, wherein said (meth)acrylic compound has a fluorene skeleton. The film adhesive for a semiconductor according to any one of claims 1 to 7, wherein the filler is a silica filler. A method for manufacturing 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 the connecting portion with the film-like adhesive for semiconductor according to any one of claims 1 to 8. 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 semiconductor device, wherein at least a part of the connecting portion is sealed with a cured film adhesive for a semiconductor according to any one of claims 1 to 8.

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