JP7351393B2 - Film adhesive for semiconductors, method for manufacturing semiconductor devices, and semiconductor devices - Google Patents

Description

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

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

For example, regarding the connection between a semiconductor chip and a substrate, the 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. Furthermore, the FC connection method is also widely used in the COC (Chip On Chip) type connection method, which connects semiconductor chips by forming connection parts (e.g. bumps and wiring) on the semiconductor chips (e.g. , see Patent Document 1).

In addition, for packages that are strongly required to be smaller, thinner, and more functional, there are chip stack type packages, POP (Package On Package), TSV ( Through-Silicon Via) and the like are also beginning to become widespread. Since such stacking/multi-stage technology arranges semiconductor chips and the like three-dimensionally, the package can be made smaller compared to a two-dimensional arrangement method. Furthermore, it is attracting attention as a next-generation semiconductor wiring technology because it is effective in improving semiconductor performance, reducing noise, reducing mounting area, and saving power.

Japanese Patent Application Publication No. 2008-294382

Incidentally, flip chip packages are rapidly becoming more sophisticated and smaller. As devices become more sophisticated and smaller, the number of bumps increases, and the pitch and gap become narrower. As the number of bumps increases and the pitch and gap narrow, more voids may occur after mounting, such as trap voids that involve the space around the bumps, and weld voids that occur at the rear of the bumps due to resin flow during crimping. be.

Furthermore, in flip-chip packages, from the viewpoint of improving productivity, it is required to shorten the crimping time during assembly of the flip-chip package. In order to shorten the crimping time, crimping at a high temperature is necessary, but with such high temperature crimping, it becomes difficult for the film adhesive for semiconductors to harden sufficiently during crimping, so voids due to moisture and foaming components occur. In addition, the minute voids caused by the above-mentioned entrainment may expand due to high temperatures, resulting in a large number of fatal voids. When a flip chip package is used for a long period of time, peeling may occur inside the package starting from these voids. When this peeling inside the package becomes large, stress is applied to the connection part and cracks occur, so peeling inside the package leads to poor connection of the package.

Furthermore, in flip-chip packages, from the viewpoint of improving productivity, it is required to perform mounting at the wafer level when assembling the flip-chip package. In this case, since a large number of packages are mounted on one bottom wafer, stress is applied to each package, causing large warpage in the bottom wafer. If the bottom wafer is warped, it becomes difficult to fix the bottom wafer to a suction table in the next sealing process, making it difficult to seal the package.

For the above reasons, film adhesives for semiconductors are required to have the ability to reduce voids and warp in addition to improving connection reliability.

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

The present inventors conducted studies focusing on the elastic modulus of a single layer film adhesive after curing in order to reduce warpage in the film adhesive. As a result, in a single-layer film adhesive, increasing the amount of filler to improve the elastic modulus increases the likelihood of voids, while increasing the amount of curing agent to reduce voids leads to better bonding. The reliability decreased, and it became clear that it was difficult to achieve both connection reliability, void reduction, and warpage reduction. Therefore, as a result of further study by the present inventors, the present inventors have developed a film adhesive that has a first adhesive layer and a second adhesive layer provided on the first adhesive layer. The present inventors have discovered 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 in a film-like adhesive, and have completed the present invention.

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

According to the above-mentioned film adhesive for semiconductors, it is possible to suppress warping of the bottom wafer even during wafer-level mounting, and to obtain excellent connection reliability without voids after mounting even when the crimping time is shortened. I can do it. Moreover, according to the film-like adhesive for semiconductors, since the pressure bonding time can be shortened, productivity can be improved. Moreover, according to the film adhesive for semiconductors, flip chip packages can be easily made highly functional and highly integrated.

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

According to the above-mentioned film adhesive for semiconductors, it is possible to suppress warping of the bottom wafer even during wafer-level mounting, and to obtain excellent connection reliability without voids after mounting even when the crimping time is shortened. I can do it. Moreover, according to the film-like adhesive for semiconductors, since the pressure bonding time can be shortened, productivity can be improved. Moreover, according to the film adhesive for semiconductors, flip chip packages can be easily made highly functional and highly integrated.

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, in order to reduce costs, there has been a tendency to use solder, copper, and the like as metals for connection parts instead of gold and the like, which are less likely to corrode. Furthermore, regarding the surface treatment of wiring and bumps, there is a tendency to use solder, copper, etc. instead of gold, etc., which are less likely to corrode, in order to reduce costs. In particular, in flip-chip packages, as costs continue to fall, metals that tend to corrode and deteriorate insulating properties tend to be used, which tends to reduce connection reliability (for example, insulation reliability). In addition, as mentioned above, in order to suppress the generation of impurities, an anti-oxidation film is sometimes formed by processing such as OSP treatment, but the anti-oxidation film reduces solder wettability during the connection process and reduces connectivity. It may cause deterioration 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 at the connection part can be removed, and even better connection reliability tends to be obtained. 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 above-mentioned flux compound may have a carboxyl group, may have two or more carboxyl groups, and may be a compound represented by the following formula (2). When such a flux compound is used, 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. A plurality of R ² 's may be the same or different from each other. ]

The melting point of the flux compound may be 150°C or lower. In this case, since the flux melts before the adhesive hardens during thermocompression bonding, and the oxide film of the solder etc. is reduced and removed, even better connection reliability is likely to be 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 develop the property of quickly and sufficiently curing the connection parts after the connection parts come into contact with the adhesive layer, and the crimping can be performed at high temperatures. In addition, even when 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 not containing a flux compound may contain a radically polymerizable compound and a thermal radical generator. In this case, since the curing speed is very high, even when pressure bonding is performed at high temperature and in a short time, voids are unlikely to occur, and even better connection reliability can be obtained.

The thermal radical generator may be a peroxide. In this case, even better handling and storage stability can be obtained, so even better connection reliability can be easily 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 type 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 that does not contain the 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, since the flux activity that suppresses the formation of an oxide film at the connection portion is obtained, even better connection reliability is likely to be obtained.

One aspect of the present invention is a semiconductor device in which connection portions of a semiconductor chip and a printed circuit board are electrically connected to each other, or a semiconductor device in which connection portions of a plurality of semiconductor chips are electrically connected to each other. The present invention relates to a method for manufacturing a semiconductor device, which includes a step of sealing at least a portion of a connecting portion using the above-mentioned semiconductor film adhesive. According to this manufacturing method, warping of the bottom wafer is suppressed even during wafer-level mounting, and even when crimping time is shortened, semiconductors with excellent connection reliability (e.g. insulation reliability) are produced without voids after mounting. You can get the equipment. That is, according to the above manufacturing method, a semiconductor device having excellent connection reliability (for example, insulation reliability) can be manufactured in a short time.

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

According to the present invention, a film for semiconductors can suppress warpage of the bottom wafer even during wafer-level mounting, and can obtain excellent connection reliability without voids after mounting even when the crimping time is shortened. adhesive can be provided. Further, according to the present invention, it is possible to provide a semiconductor device using such a film adhesive for semiconductors and a method for manufacturing the same.

FIG. 1 is a schematic cross-sectional view showing one embodiment of a 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. FIG. 4 is a process cross-sectional view 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." Furthermore, a numerical range indicated using "~" indicates a range that includes the numerical values written before and after "~" as the minimum and maximum values, respectively. Moreover, the upper limit values and lower limit values described individually can be combined arbitrarily.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below, 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 will be omitted. In addition, the positional relationships such as top, bottom, left, and right are based on the positional relationships shown in the drawings unless otherwise specified. Furthermore, the dimensional ratios in the drawings are not limited to the illustrated ratios.

<Film adhesive for semiconductors>
The film adhesive for semiconductors of the first embodiment includes a first adhesive layer and a second adhesive layer provided on the first adhesive layer, and has an elastic modulus of 3.5 at 35° C. after curing. It is 0 to 5.0 GPa.

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

The film adhesives for semiconductors of the first and second embodiments are, for example, non-conductive adhesives (film-like non-conductive adhesives for semiconductors), and are suitable for semiconductor chips and printed circuit boards. In a semiconductor device in which connection parts are electrically connected to each other, or in a semiconductor device in which connection parts of a plurality of semiconductor chips are electrically connected to each other, it is used for sealing at least a part of the connection part. It will be done.

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

Below, first, the film adhesive for semiconductors of the first embodiment will be explained in detail.

(First embodiment)
In this embodiment, the first adhesive layer and the second adhesive layer are mutually different layers, and are formed from mutually different adhesive compositions. At least one of the first adhesive layer and the second adhesive layer may be, for example, a thermosetting adhesive layer formed from a thermosetting resin composition (an adhesive layer containing a thermosetting resin composition), It may be a photocurable adhesive layer formed of a photocurable resin composition (an adhesive layer containing a photocurable resin composition). At least one of the first adhesive layer and the second adhesive layer is made of thermosetting resin from the viewpoint of reducing shrinkage under environments such as temperature cycle tests and obtaining even better connection reliability. If it is made of a composition, it is preferably a thermosetting adhesive layer, and more preferably both are thermosetting adhesive layers.

The first adhesive layer and the second adhesive layer may be adhesive layers containing a flux compound, or may be adhesive layers containing no flux compound. That is, the resin composition constituting the first adhesive layer and the second adhesive layer may be a resin composition containing a flux compound (hereinafter referred to as "flux-containing composition"); It may also be a resin composition that does not contain flux (hereinafter referred to as a "flux-free composition").

Generally, metal bonding is used to connect connecting parts from the viewpoint of ensuring sufficient connection reliability (e.g. insulation reliability). Examples include solder, tin, gold, silver, copper, and nickel. Conductive materials containing multiple types of these metals are also used. On the other hand, the surface of the metal used for the connection part oxidizes and an oxide film is formed, and impurities such as oxides adhere to the surface, resulting in impurities on the connection surface of the connection part. There are cases. If such impurities remain, the connection reliability (e.g. insulation reliability) between the semiconductor chip and the substrate or between two semiconductor chips will deteriorate, and the advantages of adopting the FC connection method described above will be lost. There is a concern that it will be stored away. Therefore, as a method of suppressing the generation of these impurities, there is a method of coating the connection portion with an oxidation prevention film, which is known as OSP (Organic Solderability Preservatives) treatment or the like. However, this anti-oxidation film may cause a decrease in solder wettability, a decrease in connectivity, etc. during the connection process. On the other hand, in this embodiment, when at least one of the first adhesive layer and the second adhesive layer is an adhesive layer containing a flux compound (for example, a thermosetting adhesive layer), the OSP treatment is not performed. Better connection reliability can be obtained.

From the viewpoint of obtaining 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 is an adhesive layer containing a flux compound. It is preferable that the adhesive layer (for example, a thermosetting adhesive layer) does not contain any adhesive.

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

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

Hereinafter, a flux-containing composition includes an epoxy resin (hereinafter referred to as "component (a)" in some cases), a curing agent (hereinafter referred to as "component (b)" in some cases), and a flux compound (hereinafter referred to in some cases as component (b)). (hereinafter referred to as "component (c)"), and if necessary, a polymer component with a weight average molecular weight of 10,000 or more (hereinafter referred to as "component (d)" as the case may be) and a filler (hereinafter, as the case may be referred to as "( An embodiment containing "e) component" will be described.

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

In order to suppress the generation of volatile components due to decomposition during connection at high temperatures, component (a) must have a thermogravimetric loss rate of 5% or less at 250℃ when the connection temperature is 250℃. It is preferable to use an epoxy resin, and when the temperature at the time of connection is 300°C, it is preferable to use an epoxy resin whose thermal weight loss rate at 300°C is 5% or less.

From the viewpoint of high heat resistance, the content of component (a) is, for example, 5% by mass or more, preferably 10% by mass or more, more preferably 15% by mass or more, based on the total mass of the flux-containing composition. It 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 weight, 10 to 50% by weight, 15 to 45% by weight, or 15 to 35% by weight.

[Component (b): Curing agent]
Examples of the component (b) include phenolic resin curing agents, acid anhydride curing agents, amine curing agents, imidazole curing agents, and phosphine curing agents. If the component (b) contains phenolic hydroxyl groups, acid anhydrides, amines, or imidazoles, it exhibits flux activity that suppresses the formation of an oxide film at the connection area, improving connection reliability and insulation reliability. can. From the viewpoint that such effects can be more easily obtained, imidazole curing agents are more preferably used. Each curing agent will be explained below.

(i) Phenolic resin curing agent There is no particular restriction on the phenolic resin curing agent as long as it has two or more phenolic hydroxyl groups in the molecule, such as phenol novolak resin, cresol novolac resin, phenol aralkyl resin. , cresol naphthol formaldehyde polycondensate, triphenylmethane type polyfunctional phenol resin, and various polyfunctional phenol resins can be used. These can be used alone or in a mixture of two or more.

The equivalent ratio of the phenolic resin curing agent to the above component (a) (number of moles of phenolic hydroxyl groups contained in the phenolic resin curing agent/number of moles of epoxy groups contained in component (a)) provides good curability and adhesive properties. From the viewpoint of storage stability, it is preferably 0.3 to 1.5, more preferably 0.4 to 1.0, and even more preferably 0.5 to 1.0. When the equivalence ratio is 0.3 or more, curability tends to improve and adhesive strength improves, and when it is 1.5 or less, unreacted phenolic hydroxyl groups do not remain excessively, and the water absorption rate decreases. It tends to be kept low and insulation reliability is improved.

(ii) Acid anhydride curing agent Examples of the acid anhydride curing agent include methylcyclohexanetetracarboxylic dianhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic dianhydride, and ethylene glycol dianhydride. Anhydrotrimellitate can be used. These can be used alone or in a mixture of two or more.

The equivalent ratio of the acid anhydride curing agent to the above component (a) (number of moles of acid anhydride groups possessed by the acid anhydride curing agent/number of moles of epoxy groups possessed by component (a)) indicates good curability. , from the viewpoint of adhesiveness and storage stability, preferably 0.3 to 1.5, more preferably 0.4 to 1.0, and even more preferably 0.5 to 1.0. When the equivalence ratio is 0.3 or more, curability tends to improve and adhesive strength improves, and when it is 1.5 or less, unreacted acid anhydride does not remain excessively, and the water absorption rate decreases. It tends to be kept low and insulation reliability is improved.

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

The equivalent ratio of the amine curing agent to the above component (a) (number of moles of active hydrogen groups in the amine curing agent/number of moles of epoxy groups in component (a)) is important for 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 equivalence ratio is 0.3 or more, curability tends to improve and adhesive strength improves, and when it is 1.5 or less, unreacted amine does not remain excessively, improving insulation reliability. There is a tendency to

(iv) Imidazole curing agent Examples of the imidazole curing agent include 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1- Cyanoethyl-2-undecylimidazole, 1-cyano-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6 -[2'-Methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2, 4-Diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')] -Ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and epoxy resin and adducts of imidazoles. Among these, 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. Alternatively, these may be used as latent curing agents that are microencapsulated.

The content of the imidazole curing agent is preferably 0.1 part by mass or more based on 100 parts by mass of component (a). When the content of the imidazole curing agent is 0.1 part by mass or more, curability tends to improve. Further, the content of the imidazole curing agent is preferably 20 parts by mass or less, more preferably 10 parts by mass. When the content of the imidazole curing agent is 20 parts by mass or less, the fluidity of the flux-containing composition during pressure bonding can be ensured, and the flux-containing composition between the connecting parts can be sufficiently removed. As a result, since the flux-containing composition is prevented from curing while intervening between the solder and the connection portion, connection failures tend to be less likely to occur. From these viewpoints, the content of the imidazole curing agent is preferably 0.1 to 20 parts by weight, more preferably 0.1 to 10 parts by weight, based on 100 parts by weight of component (a).

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

The content of the phosphine curing agent is preferably 0.1 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of component (a). When the content of the phosphine curing agent is 0.1 part by mass or more, the curability tends to improve, and when the content is 10 parts by mass or less, the flux-containing composition may harden before a metal bond is formed. Therefore, connection failures tend to occur less easily.

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

When the flux-containing composition contains a phenolic resin curing agent, an acid anhydride curing agent, or an amine curing agent as component (b), it exhibits flux activity to remove an oxide film and further improves connection reliability. I can do it.

[Component (c): 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 the oxide film on the surface of the solder or the like and facilitates metal bonding. As component (c), one type of flux compound may be used alone, or two or more types of flux compounds may be used in combination. However, component (c) does not include the curing agent that is component (b).

The flux compound preferably has a carboxyl group, and more preferably has two or more carboxyl groups, from the viewpoint of obtaining sufficient flux activity and better connection reliability. Among these, compounds having two carboxyl groups are preferred. A compound having two carboxyl groups is less likely to volatilize even at high temperatures during connection than a compound having one carboxyl group (monocarboxylic acid), and can further suppress the generation of voids. Additionally, when a compound with two carboxyl groups is used, the increase in viscosity of semiconductor film adhesives during storage and connection work is further suppressed compared to when a compound with three or more carboxyl groups is used. Therefore, the connection reliability of the semiconductor device can be further improved.

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

In 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). By doing so, even when applied as a film adhesive for semiconductors in a flip-chip connection method for metal bonding, it is possible to manufacture a semiconductor device with excellent reflow resistance and connection reliability.

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

Usually, the epoxy resin and the curing agent react and the curing reaction proceeds, and at this time, carboxylic acid, which is a flux compound, is incorporated into the curing reaction. That is, an ester bond may be formed by the reaction between the epoxy group of the epoxy resin and the carboxyl group of the flux compound. This ester bond is susceptible to hydrolysis due to moisture absorption, etc., and decomposition of this ester bond is considered to be one of the reasons for the decrease in adhesive strength after moisture absorption.

On the other hand, among compounds having a group represented by formula (1), a compound having a group in which R ¹ is an electron donating group, that is, a compound having a carboxyl group with an electron donating group in the vicinity. When containing, sufficient flux activity is obtained due to the carboxyl group, and even if the above-mentioned ester bond is formed, the electron density of the ester bond increases due to the electron donating group, suppressing the decomposition of the ester bond. be done. Furthermore, since a substituent (electron donating group) exists near the carboxyl group, it is thought that 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 using a flux-containing composition that further contains a compound in which R ¹ is an electron-donating group among compounds having a group represented by formula (1), compositional changes due to moisture absorption etc. are less likely to occur. , excellent adhesion is maintained. In addition, the above-mentioned effect can be said to mean that the curing reaction between the epoxy resin and the curing agent is less likely to be inhibited by the flux compound. It can also be expected to have the effect of improving

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

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

The alkyl group is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 5 carbon atoms. As the number of carbon atoms in the alkyl group increases, electron donating properties and steric hindrance tend to increase. Since an alkyl group having a carbon number within the above range has an excellent balance of electron donating properties and steric hindrance, the effects of the present invention are more prominently exhibited by the alkyl group.

Furthermore, the alkyl group may be linear or branched, and is preferably linear. When the alkyl group is linear, the number of carbon atoms in the alkyl group is preferably equal to or less than the number of carbon atoms in the main chain of the flux compound from the viewpoint of the balance between electron donating property 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 is preferable.

The alkoxy group is preferably an alkoxy group having 1 to 10 carbon atoms, more preferably an alkoxy group having 1 to 5 carbon atoms. As the number of carbon atoms in the alkoxy group increases, electron donating properties and steric hindrance tend to increase. Since an alkoxy group having a carbon number within the above range has an excellent balance of electron donating properties and steric hindrance, the effects of the present invention are more prominently exhibited by the alkoxy group.

Further, the alkyl group portion of the alkoxy group may be linear or branched, and is preferably linear. When the alkoxy group is linear, the number of carbon atoms in the alkoxy group is preferably equal to or less than the number of carbon atoms in the main chain of the flux compound from the viewpoint of the balance between electron donating property 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 the number of carbon atoms in the main chain of the flux compound ( n+1) or less is preferable.

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

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

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

In 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. A plurality of R ² 's may be the same or different from each other.

R ¹ has the same meaning as R ¹ in formula (1). Further, the electron donating property represented by R ² is the same as the above-mentioned example of the electron donating group explained as R ¹ . For the same reason as explained in formula (1), R ¹ in formula (2) is preferably an electron donating group.

It is preferable that n in Formula (2) is 1 or more. When n is 1 or more, compared to the case where 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. Further, 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.

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

In formula (3), R ¹ and R ² each independently represent a hydrogen atom or an electron-donating group, and m represents an integer of 0 or 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 a hydrogen atom or an electron donating group. From the viewpoint of obtaining even better connection reliability, it is preferable that at least one of R ¹ and R ² is an electron donating group. When R ¹ is an electron-donating group and R ² is a hydrogen atom, the melting point tends to be low, and the connection reliability of the semiconductor device may be 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 semiconductor devices In some cases, reliability can be further improved.

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

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 dicarboxylic acids selected from 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 sufficiently exhibit flux activity before the curing reaction between the epoxy resin and the curing agent occurs. Therefore, a semiconductor film adhesive using such a flux compound can realize a semiconductor device with even better connection reliability. Further, the melting point of the flux compound is preferably 25°C or higher, more preferably 50°C or higher. Moreover, it is preferable that the flux compound is solid at room temperature (25° C.).

The melting point of the flux compound can be measured using a general melting point measuring device. The sample whose melting point is to be measured is required to be pulverized into a fine powder and to use a very small amount to reduce the temperature deviation within the sample. A capillary tube with one end closed is often used as a sample container, but depending on the measuring device, the sample container may be sandwiched between two microscope cover glasses. Also, if the temperature is raised rapidly, a temperature gradient will occur between the sample and the thermometer, causing measurement errors, so heating at the time of measuring the melting point should be done at a rate of increase of 1°C or less per minute. desirable.

As mentioned above, since the material for measuring the melting point is prepared as a fine powder, the sample before melting is opaque due to diffuse reflection on the surface. Usually, the lower limit of the melting point is the temperature at which the sample begins to become transparent, and the upper limit is the temperature at which the sample completely melts. There are various types of measuring devices, but the most classic device is a double-tube thermometer attached to a capillary tube filled with a sample and heated in a hot bath. In order to attach a capillary tube to a double-tube thermometer, a highly viscous liquid is used as the hot bath liquid, and concentrated sulfuric acid or silicone oil is often used, so that the sample comes close to the reservoir at the tip of the thermometer. Attach. Furthermore, as a melting point measuring device, one that automatically determines the melting point while heating the material using a metal heat block and adjusting the heating while measuring the light transmittance can also be used.

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

The content of 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.

[Component (d): Polymer component with 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) has even better heat resistance and film-forming properties.

Component (d) includes, for example, phenoxy resin, polyimide resin, polyamide resin, polycarbodiimide resin, cyanate ester resin, acrylic resin, polyester resin, polyethylene resin, polyether sulfone resin, polyetherimide resin, polyvinyl acetal resin, urethane resin, etc. Examples include resins and acrylic rubbers. Among these, phenoxy resins, polyimide resins, acrylic rubbers, cyanate ester resins, and polycarbodiimide resins are preferred, and phenoxy resins, polyimide resins, and acrylic rubbers are more preferred, from the viewpoint of excellent heat resistance and film-forming properties. These component (d) can be used alone or as a mixture or copolymer of two or more. However, component (d) does not include compounds corresponding to component (a) and compounds corresponding to component (e).

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. According to such component (d), the heat resistance and film-forming properties of the flux-containing composition can be further improved.

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

In this 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 example, the following conditions can be used for the measurement.
Detector: LV4000 UV Detector (manufactured by Hitachi, Ltd., product name)
Pump: L6000 Pump (manufactured by Hitachi, Ltd., product name)
Column: Gelpack GL-S300MDT-5 (total 2 columns) (manufactured by Hitachi Chemical Co., Ltd., product name)
Eluent: THF/DMF=1/1 (volume ratio) + LiBr (0.03 mol/L) + H3PO4 (0.06 mol/L)
Flow rate: 1mL/min

When the flux-containing composition contains component (d), the ratio C a _/ C _d (mass ratio) of the content C _a of component (a) to the content C _d of component (d) is 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 adhesive strength can be obtained, and by setting the ratio C _a /C _d to 5 or less, better film forming properties can be obtained. .

[(e) Component: Filler]
The flux-containing composition may contain a filler (component (e)) as necessary. The viscosity of the flux-containing composition, the physical properties of the cured product of the flux-containing composition, etc. can be controlled by the component (e). Specifically, component (e) makes it possible to adjust the elastic modulus of the film adhesive for semiconductors after curing (for example, the elastic modulus at 35°C), suppressing the generation of voids during connection, and reducing the flux content. It is possible to reduce the moisture absorption rate of the cured product of the composition.

Component (e) includes inorganic fillers (inorganic particles), organic fillers (organic particles), and the like. Examples of inorganic fillers include insulating inorganic fillers such as glass, silica, alumina, titanium oxide, mica, and boron nitride, among which at least one filler selected from the group consisting of silica, alumina, titanium oxide, and boron nitride is used. Preferably, at least one selected from the group consisting of silica, alumina, and boron nitride is more preferable. The insulating inorganic filler may be a whisker. Examples of whiskers include aluminum borate, aluminum titanate, zinc oxide, calcium silicate, and boron nitride. Examples of the organic filler 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 a desired range, and while suppressing warping, it is easy to adjust the viscosity of the film, and the generation of voids can be more fully reduced, and furthermore, it has excellent connection reliability. In terms of the results obtained, inorganic fillers are preferably used.

The content of the inorganic filler is determined from the viewpoint of making it easy to adjust the elastic modulus to a desired range, as well as suppressing warping, making it possible to more sufficiently reduce the occurrence of voids, and furthermore, obtaining excellent connection reliability. From this point of view, 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). Component (e) may consist essentially of an inorganic filler. That is, component (e) does not need to contain substantially any organic filler. "Substantially not containing" means that the content of 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, component (e) is preferably a filler having insulation properties (insulating filler). The flux-containing composition preferably does not contain conductive metal fillers (metal particles) such as silver filler and solder filler, and conductive fillers (for example, inorganic fillers) such as carbon black.

The content of the insulating filler is determined from the viewpoints of making it easy to adjust the elastic modulus to a desired range, suppressing warpage, reducing the occurrence of voids more fully, and achieving excellent connection reliability. From the viewpoint of this, 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). Component (e) may consist essentially of an insulating filler. That is, component (e) does not need to contain substantially any conductive filler. "Substantially not containing" 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 adjusted as appropriate by surface treatment. Component (e) is preferably a filler subjected to surface treatment from the viewpoint of improving dispersibility or adhesive strength. Examples of the surface treatment agent include glycidyl-based (epoxy-based), amine-based, phenyl-based, phenylamino-based, (meth)acrylic-based, and vinyl-based compounds.

As the surface treatment, silane treatment using a silane compound such as an epoxysilane type, an aminosilane type, an acrylic silane type, etc. is preferred from the viewpoint of ease of surface treatment. The surface treatment agent is preferably at least one selected from the group consisting of glycidyl compounds, phenylamino compounds, and (meth)acrylic compounds 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 size of component (e) is preferably 1.5 μm or less from the viewpoint of preventing biting during flip-chip connection, and more preferably 1.0 μm or less from the viewpoint of excellent visibility (transparency).

The 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 becomes small. In addition, since the expansion of microvoids can be suppressed, connection reliability (particularly connection reliability when used in an environment such as a temperature cycle test) is improved. 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 component (e) is 80% by mass or less, the resin is sufficiently removed during thermocompression bonding, resulting in better connection reliability. From these viewpoints, the content of component (e) is preferably 5 to 80% by mass, more preferably 10 to 70% by mass, and 20 to 60% by mass, based on the total mass of the flux-containing composition. It is more preferable that it is mass %.

[Other ingredients]
The flux-containing composition may contain additives such as an antioxidant, a silane coupling agent, a titanium coupling agent, a leveling agent, and an ion trapping agent. These can be used alone or in combination of two or more. The amounts of these additives may be adjusted as appropriate 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 held 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 of a flux-containing composition and the other is an adhesive layer formed of a flux-free composition, In particular, the effects of the present invention can be achieved more easily. Although the reason why the effects of the present invention are significantly achieved with such an adhesive is not clear, the present inventors speculate as follows.

In other words, with conventional film adhesives containing flux compounds, a radical curing system cannot be applied because the flux component deactivates radicals, and a cationic curing system using epoxy or the like is applied. There were many things. In this curing system (reaction system), curing proceeds by a nucleophilic addition reaction, so the curing speed is slow and voids may occur after pressure bonding. With conventional film adhesives, it is presumed that defects (for example, peeling of the semiconductor material at a reflow temperature of around 260° C., poor connection at connection parts, etc.) occur due to voids during mounting. 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 above-mentioned flux-free composition for the first adhesive layer or the second adhesive layer, voids are less likely to occur even when crimping is performed at high temperature and for a short time, and the present invention It is assumed that the effect will be significant. In addition, in this 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 at a temperature range lower than the solder melting temperature. can be done. Therefore, it is possible to sufficiently suppress the occurrence of connection failures due to the scattering and flow of solder.

Hereinafter, a flux-free composition is composed of a radically polymerizable compound (hereinafter referred to as "component (A)" in some cases), a thermal radical generator (hereinafter referred to as "component (B)" in some cases), and the necessary components. An embodiment containing a polymer component (hereinafter referred to as "component (C)" in some cases) and a filler (hereinafter referred to as "component (D)" in some cases) will be described according to the following.

[Component (A): Radical 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. As component (A), a (meth)acrylic compound is preferable from the viewpoint of excellent durability, electrical insulation, and heat resistance. The (meth)acrylic compound is not particularly limited as long as it has one or more (meth)acrylic groups ((meth)acryloyl group) in the molecule, and examples include bisphenol A type, bisphenol F type, naphthalene type, (meth)acrylic compounds containing a phenol novolac type, cresol novolak type, phenol aralkyl type, biphenyl type, triphenylmethane type, dicyclopentadiene type, fluorene type, adamantane type or isocyanuric acid type; various polyfunctional (meth) ) Acrylic compounds (excluding (meth)acrylic compounds containing the above-mentioned skeleton), etc. can be used. Examples of the polyfunctional (meth)acrylic compound include pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, trimethylolpropane di(meth)acrylate, and the like. Component (A) can be used alone or in combination of two or more.

From the viewpoint of excellent heat resistance, 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. It is more preferable. It is more preferable that component (A) is a (meth)acrylate having one of the above-mentioned skeletons.

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 a flux-free composition before curing (B stage) is small, making it easier to handle. Examples of the component (A) that is solid at room temperature (25° C.) include (meth)acrylates having a bisphenol A type skeleton, a fluorene type skeleton, an adamantane type skeleton, or an isocyanuric acid type skeleton.

The number of functional groups of the (meth)acrylic group in component (A) is preferably 3 or less. When the number of functional groups is large, the curing network progresses 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 tends to proceed sufficiently in a short time, so 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 component (A), the easier the reaction will progress, and the higher the curing reaction rate will be.

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

The content of component (A) is 0.01 part by mass or more per 1 part by mass of component (C) from the viewpoint of suppressing a decrease in curability and easily inhibiting a decrease in adhesive strength. It is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more. The content of component (A) is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, per 1 part by mass of component (C), from the viewpoint of easily suppressing a decrease in film-forming properties. 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, and 0.1 to 5 parts by mass, per 1 part by mass of component (C). 5 parts by mass is more preferred.

[Component (B): 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 handling properties.

Examples of the thermal radical generator include azo compounds, peroxides (organic peroxides, etc.), and the like. As the thermal radical generator, peroxides are preferred, and organic peroxides are more preferred. In this case, radical reactions do not proceed during the process of drying the solvent when forming into a film, resulting in excellent handling properties and storage stability. Therefore, when a peroxide is used as a thermal radical generator, even better connection reliability is likely to be obtained. Examples of the organic peroxide include ketone peroxide, peroxyketal, hydroperoxide, dialkyl peroxide, diacyl peroxide, peroxydicarbonate, peroxy ester, and the like. The organic peroxide is preferably at least one selected from the group consisting of hydroperoxide, dialkyl peroxide, and peroxy ester from the viewpoint of excellent storage stability. Further, as the organic peroxide, at least one selected from the group consisting of hydroperoxide and dialkyl peroxide is preferable from the viewpoint of excellent heat resistance. Examples of the dialkyl peroxide include dicumyl peroxide and di-tert-butyl peroxide.

The content of component (B) is preferably 0.5 parts by mass or more, and more preferably 1 part by mass or more, based on 100 parts by mass of component (A), from the viewpoint of sufficient curing. 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). If the upper limit of the content of component (B) is within the above range, curing will be suppressed from rapidly progressing and the number of reaction points will increase, thereby shortening the molecular chain and reducing unreacted groups. Remaining is suppressed. Therefore, when the upper limit of the content of component (B) is within the above range, it is easy to suppress a decrease in reliability. From these viewpoints, the content of component (B) is preferably 0.5 to 10 parts by weight, more preferably 1 to 5 parts by weight, based on 100 parts by weight of component (A).

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

The glass transition temperature (Tg) of component (C) is preferably 120°C or lower, more preferably 100°C or lower, and even more 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, it is possible to easily embed bumps formed on semiconductor chips, electrodes or wiring patterns formed on substrates, etc. with the semiconductor film adhesive (hardening reaction begins). ), it is easy to suppress the occurrence of voids due to residual air bubbles. In addition, the above Tg is when 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 heating rate of 10°C/min, and a measurement atmosphere: air. 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, even more preferably 40,000 or more, particularly preferably 50,000 or more in order to exhibit good film forming properties alone. When the weight average molecular weight is 10,000 or more, it is easy to suppress a decrease in film forming properties.

[(D) Component: Filler]
Flux-free compositions contain fillers in order to control the viscosity or physical properties of the cured product, and to further suppress the generation of voids or moisture absorption when semiconductor chips and substrates or semiconductor chips are connected. It may further contain. As component (D), fillers similar to those listed as component (e) in the flux-containing composition can be used. Examples of preferred fillers are also the same. Moreover, the preferable range of the content of the inorganic filler and the preferable 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 becomes small. In addition, since the expansion of microvoids can be suppressed, connection reliability (particularly connection reliability when used in an environment such as a temperature cycle test) is improved. The content of component (D) is preferably 90% by mass or less, more preferably 80% by mass or less, even 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 component (D) is 90% by mass or less, the resin is sufficiently removed during thermocompression bonding, resulting in better connection reliability. From these viewpoints, the content of component (D) is preferably 5 to 90% by mass, more preferably 5 to 80% by mass, and further preferably 10 to 70% by mass, based on the total mass of the flux-free composition. Preferably, 20 to 60% by weight is even more preferable. 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 polymerizable compounds other than radically polymerizable compounds (for example, cationic polymerizable compounds and anionic polymerizable compounds). Further, the flux-free composition may contain other components similar to those of the flux-containing composition. These can be used alone or in combination of two or more. The amounts of these additives may be adjusted as appropriate 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 embodiment.

For example, a flux-free composition may contain the above-mentioned component (a) (epoxy resin), component (b) (curing agent), and optionally component (d) (a polymer having a weight average molecular weight of 10,000 or more). component) and component (e) (filler). When the flux-free composition is a resin composition containing these components, examples of components (a), (b), (d) and (e) that can be used and examples of preferred compounds are: The same is true for flux-containing compositions. For example, the flux-free composition preferably contains an imidazole-based curing agent as the 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 all. 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 based on 100 parts by mass of the component (a) from the viewpoint of improving curability. Further, 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 the component (d) is determined by the ratio C _{a2 /C d2 (mass ratio) of the content C a2 of} the component ( _a ) to the content C _d2 of the component (d) from 0.01 to 5, 0.05. 3 or 0.1 to 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 forming properties 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). The content is preferably at least 10% by mass, more preferably at least 10% by mass, and even more preferably at least 20% by mass. The content of component (e) is preferably 80% by mass or less, based on the total mass of the flux-free composition, from the viewpoint of sufficiently removing the resin during thermocompression bonding and improving connection reliability. It is more preferably at most 60% by mass, even more preferably at most 60% by mass.

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 will be easy to suppress the solder from scattering and flowing during connection (at the solder melting temperature or higher) and reducing connection reliability. The curing reaction rate was measured by placing 10 mg of the flux-free composition (uncured flux-free layer) into an aluminum pan and measuring the calorific value using a DSC (manufactured by PerkinElmer Japan Co., Ltd., trade name: Model DSC-7). It 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 was placed on a hot plate heated to 200°C, and after 5 seconds, the measurement sample was placed on the hot plate. Remove. The heat-treated measurement sample and the untreated measurement sample are each measured by DSC. From the obtained calorific value, the curing reaction rate is calculated using 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 anionically polymerizable epoxy resin (especially an epoxy resin with 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 based on 80 parts by mass of component (A), and it does not contain epoxy resin. is more preferable.

The adhesive layer (flux-free layer) formed from a flux-free composition can be pressure-bonded at a high temperature of 200° C. or higher. Furthermore, flip-chip packages in which connections are formed by melting metal such as solder exhibit even better hardenability.

The film adhesive for semiconductors of this embodiment obtained using the flux-containing composition and/or the flux-free composition described above has an elastic modulus of 3.0 to 5.0 GPa at 35° C. after curing. . The elastic modulus of the film adhesive for semiconductors is determined by, for example, the types and blending ratios of the components that make up the film adhesive for semiconductors (for example, the components that make up the first adhesive layer and the components that make up the second adhesive layer). It can be adjusted by adjusting. Specifically, it can be adjusted by, for example, the type and amount of the curable component, the type and amount of the polymer component, the amount of filler, etc. Moreover, the elastic modulus of the film adhesive for semiconductors can be measured by the method described in Examples.

The elastic modulus may be 3.5 GPa or more, or 4.0 GPa or more, from the viewpoint that the effects of the present invention are significant. The elastic modulus may be 4.7 GPa or less, or 4.4 GPa or less, from the viewpoint that the effects of the present invention are significant. That is, the above 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 ˜5.0 GPa, 4.0-4.7 GPa or 4.0-4.4 GPa.

The filler content of the film adhesive for semiconductors 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 semiconductors, from the viewpoint that the effects of the present invention are significant. 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% by mass based on the total mass of the film adhesive for semiconductors, from the viewpoint that the effect of the present invention is remarkable. % or more, 35% by mass or more, or 45% by mass or more, and 60% by mass or less, 55% by mass or less, or 50% by mass or less. In addition, 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 adhesive for semiconductors, from the viewpoint that the effects of the present invention are significant. It may be 5% by mass or more, 10% by mass or more, or 15% by mass or more, and may be 30% by mass or less, 25% by mass or less, or 20% by mass or less.

Regarding the thickness of the film adhesive for semiconductors, if the sum of the heights of the above connection parts is x and the total thickness of the film adhesive for semiconductors is y, then the relationship between x and y is as follows: From the viewpoint of connectivity and adhesive fillability, it is preferable to satisfy 0.70x≦y≦1.3x, and more preferably to satisfy 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, the adhesive layer containing a flux compound) may be, for example, 1 to 50 μm, 3 to 50 μm, 4 to 30 μm, 5 to 20 μm. It's good.

The thickness of the second adhesive layer (for example an adhesive layer not containing a flux compound) may be, for example, from 7 to 50 μm, from 8 to 45 μm, from 10 to 40 μm.

The ratio of the thickness of the second adhesive layer (for example, an adhesive layer that does not contain a flux compound) to the thickness of the first adhesive layer (for example, an adhesive layer that contains a flux compound) (thickness of the second adhesive layer / adhesive layer that does not contain a flux compound) The thickness of one adhesive layer may be, for example, 0.1 to 10.0, 0.5 to 6.0, or 1.0 to 4.0.

The film adhesive for semiconductors may further include layers other than the first adhesive layer and the second adhesive layer, but it is preferable to consist of only the first adhesive layer and the second adhesive layer. . In addition, the film adhesive for semiconductors of this embodiment can be applied on the surface of the first adhesive layer opposite to the second adhesive layer, and/or on the surface of the second adhesive layer opposite to the first adhesive layer. A base film and/or a protective film may be provided on the opposite surface.

In the film adhesive for semiconductors, the first adhesive layer and the second adhesive layer may be adjacent to each other. In this case, 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 may not be 3.0 to 5.0 GPa. The details of the film adhesive for semiconductors of the second embodiment are as follows: It may be the same as the film adhesive for semiconductors.

<Method for producing film adhesive for semiconductors>
The film adhesive for semiconductors of this embodiment can be prepared by, for example, preparing a first film adhesive having a first adhesive layer and a second film adhesive having a second adhesive layer; It can be obtained by bonding together a first film adhesive having one adhesive layer and a second film adhesive having a second adhesive layer.

A film adhesive (a first film adhesive and/or a second film adhesive) comprising an adhesive layer formed of a flux-containing composition (an adhesive layer containing a flux-containing composition) as an adhesive layer. In the preparing step, for example, first, component (a), component (b), component (c), and other components such as component (d) and component (e), which are added as necessary, are mixed in an organic solvent. A resin varnish (coating varnish) is prepared by adding the resin to the liquid and dissolving or dispersing it by stirring, mixing, kneading, etc. Thereafter, a resin varnish is applied onto the release-treated base film using a knife coater, roll coater, applicator, etc., and the organic solvent is reduced by heating to coat the flux-containing composition onto the base film. An adhesive layer containing the following can be formed.

The organic solvent used for preparing the resin varnish is preferably one having the property of uniformly dissolving or dispersing each component, such as dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, diethylene glycol dimethyl ether, Mention may be made of 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 carried out using, for example, a stirrer, a miller, 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 used to volatilize the organic solvent, and polyolefin films such as polypropylene film and polymethylpentene film, polyethylene terephthalate film, and polyethylene naphthalate film can be used. Examples include polyester films, polyimide films, and polyetherimide films. The base film is not limited to a single layer made of these films, but may be a multilayer film made of two or more types of materials.

The drying conditions when volatilizing the organic solvent from the resin varnish applied to the base film are preferably such that the organic solvent is sufficiently volatilized, specifically, at 50 to 200°C for 0.1 to 90 minutes. It is preferable to perform heating. It is preferable that the organic solvent be removed to 1.5% by mass or less based on the total amount of the first film adhesive, as long as it does not affect voids or viscosity adjustment after mounting.

A film adhesive (a first film adhesive and/or a second film adhesive) comprising an adhesive layer formed of a flux-free composition (an adhesive layer containing a flux-free composition) as an adhesive layer. ), for example, the (A) component and the (B) component, and other components such as the (C) component added as necessary, or the (a) component and (b) component, and the necessary components. Depending on the conditions, an adhesive layer containing a flux-free composition can be formed on the base film in the same manner as for the first adhesive layer, except for using other components such as component (d).

Examples of the method for bonding the first film adhesive and the second film adhesive include hot pressing, roll lamination, vacuum lamination, and the like. Lamination may be performed, for example, under heating conditions of 30 to 120°C.

The film-like adhesive for semiconductors of the present embodiment can be produced, for example, by forming either the first adhesive layer or the second adhesive layer on the base film, and then applying the resulting first adhesive layer or second adhesive layer to the base film. 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 base material-attached film adhesive described above.

<Semiconductor device>
The semiconductor device of this embodiment will be explained below using FIGS. 1 and 2. FIG. 1 is a schematic cross-sectional view showing one embodiment of a semiconductor device of the present invention. As shown in FIG. 1(a), the semiconductor device 100 includes a semiconductor chip 10 and a substrate (circuit wiring board) 20 facing each other, and wiring 15 arranged on surfaces of the semiconductor chip 10 and the substrate 20 facing each other. , a connection bump 30 that connects the wiring 15 of the semiconductor chip 10 and the substrate 20 to each other, and an adhesive (for example, a flux-containing composition and a flux-free composition) that fills the gap between the semiconductor chip 10 and the substrate 20 without any gaps. It has a sealing part 40 made of a cured product. The semiconductor chip 10 and the 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 part 40 has an upper part 40a containing a cured product of a flux-containing composition or a flux-free composition, and a lower part 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, the semiconductor device 200 includes a semiconductor chip 10 and a substrate 20 facing each other, bumps 32 arranged on surfaces of the semiconductor chip 10 and the substrate 20 facing each other, and The sealing portion 40 is made of a cured adhesive (for example, a flux-containing composition and a flux-free composition) that fills the gap between the substrates 20 without any gaps. The semiconductor chip 10 and the substrate 20 are flip-chip connected by connecting the opposing bumps 32 to each other. The bump 32 is sealed with a cured adhesive and is isolated from the external environment. The sealing part 40 has an upper part 40a containing a cured product of a flux-containing composition or a flux-free composition, and a lower part 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, the semiconductor device 300 is similar to the semiconductor device 100 except that the two semiconductor chips 10 are flip-chip connected by wiring 15 and connection bumps 30. As shown in FIG. 2B, the semiconductor device 400 is similar to the semiconductor device 200 except that the two semiconductor chips 10 are flip-chip connected by bumps 32.

The semiconductor chip 10 is not particularly limited, and elemental semiconductors made of the same type 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 unnecessary parts of the metal film are etched on the surface of an insulating substrate whose main component is glass epoxy, polyimide, polyester, ceramic, epoxy, bismaleimide triazine, etc. A circuit board having wiring (wiring pattern) 15 formed by removal, a circuit board having wiring 15 formed on the surface of the insulating substrate by metal plating, etc., and wiring by printing a conductive substance on the surface of the insulating substrate. A circuit board on which 15 is formed can be used.

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

Among the above-mentioned metals, gold, silver, and copper are preferred, and silver and copper are more preferred, from the viewpoint of providing a package with excellent electrical conductivity and thermal conductivity at the connecting portion. From the viewpoint of providing a package with reduced cost, silver, copper, and solder, which are inexpensive materials, are preferable, copper and solder are more preferable, and solder is even more preferable. If an oxide film is formed on the surface of a metal at room temperature, productivity may decrease and costs may increase. Therefore, from the viewpoint of suppressing the formation of an oxide film, gold, silver, copper, and solder are preferable. , solder is more preferred, and gold and silver are even more preferred.

The surfaces of the wiring 15 and bumps 32 are mainly made of gold, silver, copper, solder (main components are, for example, tin-silver, tin-lead, tin-bismuth, tin-copper, etc.), tin, nickel, etc. The metal layer as a component may be formed by plating, for example. This metal layer may be composed of only a single component or a plurality of components. Further, the metal layer may have a single layer structure or a structure in which a plurality of metal layers are stacked.

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

As a method of 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, so that the semiconductor chip 10 and the interposer 50 are flip-chip connected. ing. The gap 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 part 40 . On the surface of the semiconductor chip 10 on the side opposite to the interposer 50, the semiconductor chips 10 are repeatedly stacked with wirings 15, connection bumps 30, and sealing parts 40 interposed therebetween. The wirings 15 on the pattern surfaces on the front and back sides of the semiconductor chip 10 are connected to each other by through electrodes 34 filled in holes that penetrate inside the semiconductor chip 10 . Note that as the material of the through electrode 34, copper, aluminum, etc. can be used.

Such TSV technology makes it possible to obtain signals even from the back side of a semiconductor chip, which is not normally used. Furthermore, since the through electrodes 34 are vertically passed through the semiconductor chips 10, the distances between the opposing semiconductor chips 10 and between the semiconductor chips 10 and the interposer 50 can be shortened, allowing for flexible connections. The film adhesive for semiconductors of this embodiment can be applied as a film adhesive for semiconductors between opposing semiconductor chips 10 and between semiconductor chips 10 and interposer 50 in such TSV technology.

Furthermore, with a highly flexible bump forming method such as area bump chip technology, a semiconductor chip can be directly mounted on a motherboard without using an interposer. The film adhesive for semiconductors of this embodiment can also be applied when such semiconductor chips are directly mounted on a motherboard. Note that the film adhesive for semiconductors of this embodiment can also be applied to seal a gap between two printed circuit boards when laminating them.

<Method for manufacturing semiconductor devices>
Regarding the method for manufacturing a semiconductor device of this embodiment, using FIG. 4, the first adhesive layer is an adhesive layer formed of a flux-containing composition, and the second adhesive layer is formed of a flux-free composition. An example will be explained in which the adhesive layer is used as an adhesive layer. 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.

FIG. 4 is a diagram schematically showing an embodiment of the method for manufacturing a semiconductor device of the present invention, and FIG. 4(a), FIG. 4(b), and FIG. A cross section is shown.

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 wiring 15. This solder resist 60 does not necessarily need to be provided. However, by providing a solder resist on the substrate 20, it is possible to suppress the occurrence of bridges between the wirings 15 and improve connection reliability and insulation reliability. The solder resist 60 can be formed using, for example, a commercially available solder resist ink for packages. 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 Manufacturing Co., Ltd., trade name).

Next, as shown in FIG. 4(a), connection bumps 30 are formed in the openings of the solder resist 60. Then, as shown in FIG. 4B, on the substrate 20 on which the connection bumps 30 and the solder resist 60 are formed, the surface on the side of the second adhesive layer 41b containing the flux-free composition becomes the substrate 20 side. The film adhesive for semiconductors (hereinafter referred to as "film adhesive" in some cases) 41 of this embodiment is applied as shown in FIG. The film adhesive 41 can be attached by heat pressing, roll lamination, vacuum lamination, or the like. The supply area and thickness of the film adhesive 41 are appropriately set depending on the sizes of the semiconductor chip 10 and the substrate 20, the height of the connection bumps 30, and the like. Note that the film adhesive 41 may be attached so that the surface on the first adhesive layer 41a side containing the flux-containing composition is on the substrate 20 side.

After the film adhesive 41 is attached to the substrate 20 as described above, the wiring 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 pressed together while being heated at a temperature higher than the melting point of the connection bumps 30, and as shown in FIG. 4(c), the semiconductor chip 10 and the substrate 20 are connected and a film-like The gap between the semiconductor chip 10 and the substrate 20 is sealed and filled by the sealing portion 40 made of a cured adhesive 41. Through the above steps, a semiconductor device 600 is obtained.

The crimping time may be, for example, 5 seconds or less. In this embodiment, since the film 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 method for manufacturing a semiconductor device of this embodiment, after positioning, the semiconductor device is temporarily fixed (through a film adhesive for semiconductors), and heat-treated in a reflow oven to melt the connection bumps 30 and make the semiconductor The chip 10 and the substrate 20 may be connected. At the temporary fixing stage, it is not necessarily necessary to form a metal bond, so compared to the above-mentioned method of crimping while heating, crimping can be performed with a lower load, in a shorter time, and at a lower temperature, improving productivity and making the connection easier. deterioration of the parts can be suppressed.

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 adhesive proceeds, more preferably a temperature at which it is completely cured. The heating temperature and heating time are set appropriately.

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

From the viewpoint of improving productivity, by supplying a semiconductor film adhesive to a semiconductor wafer in which a plurality of semiconductor chips 10 are connected, and then dicing to separate the semiconductor wafer into individual pieces, the semiconductor film adhesive is applied onto the semiconductor chips 10. A structure provided with the agent may be obtained. The film adhesive for semiconductors may be supplied so as to embed wiring, bumps, etc. on the semiconductor chip 10 by, for example, a pasting method such as hot pressing, roll lamination, or vacuum lamination. In this case, since the amount of resin supplied is constant, productivity is improved, and generation of voids and deterioration of dicing performance due to insufficient embedding can be suppressed.

The connection load is set in consideration of the variation in the number and height of the connection bumps 30, the amount of deformation of the wiring that receives the connection bumps 30 due to pressurization, or the bumps at the connection portion. Although it is preferable that the temperature of the connection portion be equal to or higher than the melting point of the connection bump 30, the connection temperature may be any temperature at which metal bonding of the respective connection portions (bumps and wiring) is formed. When the connection bumps 30 are solder bumps, the temperature is preferably about 240° C. or higher.

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

The film adhesive for semiconductors of this embodiment also exhibits excellent reflow resistance and connection reliability in the flip-chip connections 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 Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the Examples.

<Preparation of monolayer films A and B>
The compounds used to produce the single-layer film A with a flux-containing layer and the 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, product name: jER1032H60)
・Bisphenol F type liquid epoxy (manufactured by Mitsubishi Chemical Corporation, product name: jERYL983U)
(b) Curing agent/2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct (manufactured by Shikoku Kasei Kogyo Co., Ltd., product name: 2MAOK-PW) )
(c) Flux compound/glutaric acid (manufactured by Tokyo Kasei Co., Ltd., melting point approximately 98°C)
・2-Methylglutaric acid (manufactured by Sigma-Aldrich, melting point approximately 78°C)
(d) Polymer component - phenoxy resin (manufactured by Toto Kasei Co., Ltd., product name: ZX1356-2, Tg: about 71°C, weight average molecular weight Mw: about 63000)
(e) Filler/silica filler (manufactured by Admatex Co., Ltd., product name: SE2050, average particle size: 0.5 μm)
・Epoxy silane surface treatment filler (manufactured by Admatex Co., Ltd., product name: SE2050-SEJ, average particle size: 0.5 μm)
・Methacrylic surface treated nano silica filler (manufactured by Admatex Co., Ltd., product name: YA050C-MJE, average particle size: approximately 50 nm)
・Organic filler (resin filler, manufactured by Rohm and Haas Japan Co., Ltd., EXL-2655: core-shell type organic fine particles)

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

The obtained coating varnish was applied onto a base film (manufactured by Teijin DuPont Films Co., Ltd., trade name: Purex A54) using a small precision coating device (Nasui Seiki), and then placed in a clean oven (ESPEC Co., Ltd.). (80°C/10 min) to form single layer films (A-1), (A-2), (A-3), (A-4), (B-1) and (BB-2) was obtained. The thickness of the flux-containing layer in single-layer film A and the thickness of the non-flux-containing layer in single-layer film B were both 20 μm.

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

(B) Thermal radical generator ・Dicumyl peroxide (manufactured by NOF Corporation, product name: Percmil (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 in the production of single-layer films A and B was used.

A (meth)acrylic compound, a polymer component, and a filler in the 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%. Then, beads of Φ1.0 mm and beads of Φ2.0 mm were 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 type pulverizer P -7) for 30 minutes. After stirring, the beads were removed by filtration. Next, a thermal radical generator was added to the obtained mixture, and the mixture was stirred and mixed to prepare a coating varnish.

The obtained coating varnish was applied onto a base film (manufactured by Teijin DuPont Films Ltd., trade name: Purex A54) using a small precision coating device (manufactured by Renai Seiki Co., Ltd.), and then placed in a clean oven ( (manufactured by ESPEC Corporation) (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 each 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)
Among the single-layer films produced above, two identical or different films were laminated at 50°C to produce a film adhesive having a total thickness of 40 μm. The combinations of single layer films were as shown in Table 1. Note that when the same film is used, there is no second adhesive layer, so Table 1 shows only the first adhesive layer.

<Evaluation>
The film adhesives obtained in Examples and Comparative Examples and the semiconductor devices manufactured using the film adhesives were subjected to elastic modulus measurement, chip warpage evaluation, initial connectivity evaluation, and void evaluation using the methods shown below. , and temperature cycle test evaluation. The results are shown in Table 1.

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

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

(Chip warpage evaluation)
The film adhesive obtained in the example or comparative example was coated with a silicon chip (length 10 mm x width 10 mm x thickness) using a vacuum laminator (manufactured by NPC Corporation, product name: LM-50X50-S). 0.05 mm, oxide film coating). Next, the sample laminated with the film adhesive was cured in a clean oven (manufactured by ESPEC Corporation) to obtain a test sample. The curing conditions were 240°C for 1 hour.

Moiré measurement was performed using a 3D heating surface shape measuring device ThermoRay PS200S (manufactured by Akrometrix), and those with warpage results of less than 130 μm were designated as "A", those with warpage of 130 μm or more and less than 150 μm were designated as "B", and those with warpage of 150 μm or more were designated as "B". The chip warpage was evaluated with a rating of "C". Specifically, the test sample was placed under glass with vertical stripes, and the warp of the test sample was measured by shining light from an oblique direction and measuring and analyzing the interference fringes with a camera.

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

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

(Void evaluation)
For the semiconductor device manufactured by the above method, an external image was taken using an ultrasonic imaging diagnostic device (product name: Insight-300, manufactured by Insight Corporation), and an external image was taken using a scanner GT-9300UF (manufactured by Seiko Epson Corporation, product name). An image of the adhesive part (a part made of a cured film adhesive for semiconductors) on the chip is captured, and void parts are identified by color tone correction and two-tone conversion using image processing software Adobe Photoshop (registered trademark). , The proportion occupied by the void portion was calculated using a histogram. Taking the area of the adhesive part on the chip as 100%, the case where the void occurrence rate is 5% or less is rated "A", the case where it is more than 5% and 10% or less is rated "B", and the case where it is more than 10% is rated " 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. Next, after-curing was performed in a clean oven (manufactured by ESPEC Corporation) at 175° C. for 5 hours to obtain a package. Next, this package was connected to a thermal cycle tester (manufactured by Kusumoto Kasei Co., Ltd., product name: THERMAL SHOCK CHAMBER NT1200), a 1 mA current was applied, and the test was carried out at 25°C for 2 minutes/-55°C for 15 minutes/25°C for 2 minutes/125°C. The change in connection resistance was evaluated after repeating 1000 cycles, each cycle consisting of 15 minutes at 15 minutes at 25 degrees Celsius and 2 minutes at 25 degrees Celsius. If there is no significant change after 1000 cycles compared to the initial resistance waveform (no difference or a difference of less than 1Ω), it is rated “A”, and if there is a difference of 1Ω or more, it is rated “B”. ”.

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

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

Claims (10)

A film adhesive for semiconductors containing a filler,
comprising 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 not containing the flux compound is composed of a radical curing adhesive,
A film adhesive for semiconductors, wherein 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 according to claim 1, wherein the flux compound has a carboxyl group. The film adhesive for semiconductors according to claim 1, wherein the flux compound has two or more carboxyl groups. The film 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. A plurality of R ² 's may be the same or different from each other. ] The film adhesive for semiconductors according to any one of claims 1 to 4, wherein the flux compound has a melting point of 150° C. or lower. The film adhesive for semiconductors according to any one of claims 1 to 5, wherein the thermosetting adhesive layer that does not contain a flux compound contains a (meth)acrylic compound. The film adhesive for semiconductors according to claim 6, wherein the (meth)acrylic compound has a fluorene type skeleton. The film adhesive for semiconductors 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 the step of sealing at least a portion of the connection portion using the semiconductor film adhesive 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 portion of the connection portion is sealed with a cured product of the film adhesive for semiconductors according to any one of claims 1 to 8.

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