WO2020136904A1

WO2020136904A1 - Adhesive film, integrated dicing/die bonding film, and method for producing semiconductor package

Info

Publication number: WO2020136904A1
Application number: PCT/JP2018/048593
Authority: WO
Inventors: 達也矢羽田; 慎太郎橋本
Original assignee: 日立化成株式会社
Priority date: 2018-12-28
Filing date: 2018-12-28
Publication date: 2020-07-02
Also published as: JP7322897B2; JPWO2020136904A1

Abstract

This adhesive film contains an adhesive agent layer comprising a thermosetting resin composition. When the shear viscosity of the adhesive agent layer at 40°C is denoted by η₄₀ and the shear viscosity of the adhesive agent layer at 80°C is denoted by η₈₀, the value of η₈₀ is 2500-4500 Pa·s and the ratio (η₄₀/η₈₀) of η₄₀ relative to η₈₀ is 25-200. This integrated dicing/die bonding film comprises the adhesive agent layer of the adhesive film and a pressure-sensitive adhesive agent layer provided on one surface of the adhesive agent layer.

Description

Adhesive film, dicing/die bonding integrated film, and method for manufacturing semiconductor package

The present disclosure relates to an adhesive film, a dicing/die bonding integrated film, and a method for manufacturing a semiconductor package.

Conventionally, silver paste has been mainly used for joining the semiconductor element and the supporting member in the manufacturing process of the semiconductor device. However, with the recent miniaturization and integration of semiconductor elements, problems tend to occur in wire bonding due to the protrusion of the silver paste or the inclination of the semiconductor elements. When an adhesive composition is used instead of the silver paste, it is difficult to make the thickness of the adhesive layer sufficiently uniform, and there are problems such as the occurrence of voids (voids) in the adhesive layer.

In recent years, film-like adhesives have come to be used for joining semiconductor elements and supporting members. For example, Patent Document 1 discloses a sheet for both dicing and die bonding, which includes a base material, a wire embedding layer, and an insulating layer. By performing dicing with the insulating layer of this sheet and the wafer bonded together, the semiconductor wafer and the wire embedding layer are separated. The semiconductor element and the supporting member are joined by thermocompression bonding the semiconductor element to the supporting member via the wire embedding layer.

By the way, as a form of a semiconductor device, a stacked MCP (Multi Chip Package) having a configuration in which semiconductor elements are stacked in multiple stages is prevalent. Examples of the stacked MCP include a wire-embedded semiconductor package and a chip-embedded semiconductor package (see Patent Document 2). The adhesive film used to manufacture the wire-embedded semiconductor package is called FOW (Film Over Wire). It is called FOD (Film Over Die) as an adhesive film used to manufacture chip-embedded semiconductor packages. These adhesive films are required to have excellent embedding properties for wires or semiconductor elements.

Japanese Patent Laid-Open No. 2007-53240 JP, 2014-175459, A

With the progress of miniaturization of semiconductor elements (chips), the pressing force per unit area tends to become excessively large in the thermocompression bonding process in the manufacturing process of semiconductor packages. This may cause a phenomenon (hereinafter, referred to as “bleed”) in which the adhesive composition forming the adhesive film protrudes from the semiconductor element, or the adhesive film is excessively crushed to cause electrical failure. In particular, if the FOD composition is changed to improve the fluidity in the thermocompression bonding process in order to improve the embedding property of the adhesive film (FOD) used for manufacturing the chip-embedding type semiconductor package, bleeding becomes remarkable. .. For example, the protruding adhesive composition may rise up to the upper surface of the semiconductor element, which may cause electrical failure or wire bonding failure. That is, the conventional adhesive film cannot always sufficiently achieve both excellent embeddability for a semiconductor element and suppression of bleed in the process of manufacturing a chip embedded type package, and there is room for improvement in this respect. there were.

The present disclosure provides an adhesive film including an adhesive layer made of a thermosetting resin composition, which has excellent embeddability in a semiconductor element and can sufficiently suppress bleeding in a thermocompression bonding process. To do. The present disclosure provides a dicing/die bonding integrated film including the adhesive layer of the adhesive film, and a method for manufacturing a semiconductor package using the film.

The adhesive film according to the present disclosure includes an adhesive layer made of a thermosetting resin composition, the shear viscosity of the adhesive layer at 40° C. is η _40, and the shear viscosity of the adhesive layer at 80° C. is η. When ₈₀ is eta ₈₀ is 2500 ~ 4500Pa · s, the ratio of eta ₄₀ for _{_{_{η 80 (η 40 / η 80}}} ) is 25-200. The shear viscosity η ₄₀ at 40° C. of the adhesive layer is, for example, 100,000 Pa·s or more.

The present inventors have examined the mechanism of bleeding in the thermocompression bonding process in the process of manufacturing a chip-embedded semiconductor package. As a result, the following findings were obtained. That is, conventionally, it has been considered that bleeding mainly occurs as the adhesive layer is gradually crushed by the pressing force applied to the adhesive layer. However, rather than this, it was found that the impact of the tool for applying a pressing force when the tool descends and comes into contact with the object is the main cause of bleeding. The adhesive film according to the present disclosure is designed based on this finding, and the shear viscosity η ₄₀ of the adhesive layer at 40° C. is set to 25 to 200 times the shear viscosity η ₈₀ at 80° C. By increasing the shear viscosity η ₄₀ at 40° C., the impact at the initial stage of the thermocompression bonding process, that is, the stage where the tool descends and contacts the object, and the stage where the adhesive layer is not sufficiently heated It is possible to sufficiently suppress the bleeding caused by. On the other hand, when the shear viscosity η ₈₀ of the adhesive layer at 80° C. is 2500 to 4500 Pa·s, excellent embeddability can be achieved.

The adhesive film according to the present disclosure is useful for manufacturing a chip-embedded semiconductor package. That is, in the manufacturing process of the chip-embedded semiconductor package, the adhesive layer can be used to embed the first semiconductor element on the substrate and to bond the second semiconductor element to the substrate.

In order for the adhesive layer to satisfy the above conditions for η ₄₀ and η ₈₀ , for example, one or more of the following items relating to the composition of the thermosetting resin composition forming the adhesive layer may be used. You can adopt the item.
-The thermosetting resin composition contains a phenol resin having a softening point of more than 40°C and less than 70°C.
The content of the epoxy resin which is liquid at 25° C. (based on the total mass of the epoxy resin contained in the thermosetting resin composition) is less than 40 mass %.
The thermosetting resin composition contains an epoxy resin having an alicyclic structure, a curing agent (for example, phenol resin), and an elastomer (for example, acrylic resin).
-The thermosetting resin composition contains an inorganic filler.
-The thermosetting resin composition contains a curing accelerator.

The adhesive film of the present disclosure may be the adhesive layer itself or may be provided with a base film provided on one surface of the adhesive layer from the viewpoint of ease of use. Further, the dicing/die-bonding integrated film may be formed by combining the adhesive layer and the pressure-sensitive adhesive layer. That is, the dicing/die-bonding integrated film according to the present disclosure includes an adhesive layer of the adhesive film according to the present disclosure and a pressure-sensitive adhesive layer provided on one surface of the adhesive layer, and if necessary. A protective film may be further provided so as to cover the adhesive layer.

The present disclosure provides a method for manufacturing a semiconductor package using the above dicing/die bonding integrated film. For example, a chip-embedded semiconductor package is manufactured through the following steps.
A step of preparing a structure including a substrate and a first semiconductor element mounted on the surface of the substrate.
A step of bonding the adhesive layer of the dicing/die bonding integrated film according to the present disclosure to the wafer.
A step of dividing the wafer bonded to the adhesive layer into a plurality of second semiconductor elements.
A step of picking up from the pressure-sensitive adhesive layer a laminate including the adhesive piece formed by dividing the adhesive layer into individual pieces and the second semiconductor element.
A step of thermocompression-bonding the above laminated body to the substrate so that the first semiconductor element is embedded in the adhesive piece.
-A step of curing the adhesive piece by heat treatment.

According to the method for manufacturing a chip-embedded semiconductor package, the first semiconductor element can be appropriately embedded in the adhesive piece and bleeding can be sufficiently suppressed in the thermocompression bonding process.

According to the present disclosure, an adhesive film including an adhesive layer made of a thermosetting resin composition, which has excellent embeddability in a semiconductor element and can sufficiently suppress bleeding in a thermocompression bonding process. Will be provided. According to the present disclosure, there is provided a dicing/die-bonding integrated film including the adhesive layer of the adhesive film, and a method for manufacturing a semiconductor package using the film.

FIG. 1 is a sectional view schematically showing an example of a semiconductor package. FIG. 2 is a cross-sectional view schematically showing an example of a laminated body including an adhesive piece and a second semiconductor element. FIG. 3 is a cross-sectional view schematically showing a process of manufacturing the semiconductor package shown in FIG. FIG. 4 is a cross-sectional view schematically showing a process of manufacturing the semiconductor package shown in FIG. FIG. 5 is a cross-sectional view schematically showing a process of manufacturing the semiconductor package shown in FIG. FIG. 6 is a cross-sectional view schematically showing a process of manufacturing the semiconductor package shown in FIG. 7(a) to 7(e) are cross-sectional views schematically showing a process of manufacturing a laminated body including the adhesive piece and the second semiconductor element.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the following description, the same or corresponding parts will be denoted by the same reference symbols, without redundant description. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios. In addition, the description of "(meth)acryl" in this specification means "acryl" and its corresponding "methacryl."

<Semiconductor package>
FIG. 1 is a sectional view schematically showing a chip-embedded semiconductor package according to this embodiment. A semiconductor package 100 shown in this figure includes a substrate 10, a first semiconductor element Wa mounted on the surface of the substrate 10, and a first sealing layer 20 that seals the first semiconductor element Wa. , A second semiconductor element Wb arranged above the first semiconductor element Wa, and a second sealing layer 40 sealing the second semiconductor element Wb.

The substrate 10 has

circuit patterns

10a and 10b on its surface. From the viewpoint of suppressing the warpage of the semiconductor package 100, the thickness of the substrate 10 is, for example, 90 to 180 μm, and may be 90 to 140 μm. The substrate 10 may be an organic substrate or a metal substrate such as a lead frame.

In the present embodiment, the first semiconductor element Wa is a controller chip for driving the semiconductor package 100. The first semiconductor element Wa is adhered onto the circuit pattern 10a via an adhesive 15, and is also connected to the circuit pattern 10b via a first wire 11. The shape of the first semiconductor element Wa in a plan view is, for example, a rectangle (square or rectangle). The length of one side of the first semiconductor element Wa is, for example, 6 mm or less, and may be 2 to 5 mm or 1 to 4 mm. The thickness of the first semiconductor element Wa is, for example, 10 to 150 μm, and may be 20 to 100 μm.

The second semiconductor element Wb has a larger area than the first semiconductor element Wa. The second semiconductor element Wb is mounted on the substrate 10 via the first sealing layer 20 so that the entire first semiconductor element Wa and a part of the circuit pattern 10b are covered. The shape of the second semiconductor element Wb in a plan view is, for example, a rectangle (square or rectangle). The length of one side of the second semiconductor element Wb is, for example, 20 mm or less, and may be 4 to 20 mm or 4 to 12 mm. The thickness of the second semiconductor element Wb is, for example, 10 to 170 μm, and may be 20 to 120 μm. The second semiconductor element Wb is connected to the circuit pattern 10b via the second wire 12 and is sealed by the second sealing layer 40.

The first sealing layer 20 is made of a cured product of the adhesive piece 20P (see FIG. 2). Note that, as shown in FIG. 2, the adhesive piece 20P and the second semiconductor element Wb have substantially the same size. The laminated body 30 illustrated in FIG. 2 includes the adhesive piece 20P and the second semiconductor element Wb, and is also referred to as a semiconductor element with an adhesive. The laminated body 30 is manufactured through a dicing process and a pickup process as described later (see FIG. 7).

<Semiconductor package manufacturing method>
A method of manufacturing the semiconductor package 100 will be described. First, as shown in FIG. 3, a structure 50 including the substrate 10 and the first semiconductor element Wa mounted on the substrate 10 is manufactured. That is, the first semiconductor element Wa is arranged on the surface of the substrate 10 via the adhesive 15. After that, the first semiconductor element Wa and the circuit pattern 10b are electrically connected by the first wire 11.

Next, as shown in FIG. 4, the adhesive piece 20P of the separately prepared laminate 30 is pressed against the substrate 10. As a result, the first semiconductor element Wa and the first wire 11 are embedded in the adhesive piece 20P. The thickness of the adhesive piece 20P may be appropriately set according to the thickness of the first semiconductor element Wa and the like, and may be, for example, 20 to 200 μm, 30 to 200 μm or 40 to 150 μm. .. By setting the thickness of the adhesive piece 20P in the above range, it is possible to sufficiently secure the distance (distance G in FIG. 5) between the first semiconductor element Wa and the second semiconductor element Wb. The distance G is preferably, for example, 50 μm or more, and may be 50 to 75 μm or 50 to 80 μm.

The pressure bonding of the adhesive piece 20P to the substrate 10 is preferably carried out, for example, under conditions of 80 to 180° C. and 0.01 to 0.50 MPa for 0.5 to 3.0 seconds. Next, the adhesive piece 20P is cured by heating. This curing treatment is preferably carried out, for example, under conditions of 60 to 175° C. and 0.01 to 1.0 MPa for 5 minutes or more. As a result, the first semiconductor element Wa is sealed with the cured product (first sealing layer 20) of the adhesive piece 20P (see FIG. 6). The curing process of the adhesive piece 20P may be performed in a pressurized atmosphere from the viewpoint of reducing voids. After electrically connecting the second semiconductor element Wb and the circuit pattern 10b with the second wire 12, the second semiconductor element Wb is sealed by the second sealing layer 40, whereby the semiconductor package 100 is completed. (See FIG. 1).

<Method of manufacturing semiconductor device with adhesive>
An example of a method of manufacturing the laminated body 30 (semiconductor element with adhesive) shown in FIG. 2 will be described with reference to FIGS. 7A to 7E. First, the dicing/die-bonding integrated film 8 (hereinafter, referred to as “film 8” in some cases) is placed in a predetermined device (not shown). The film 8 includes the base material layer 1, the pressure-sensitive adhesive layer 2, and the adhesive layer 20A (adhesive film) in this order. The base material layer 1 is, for example, a polyethylene terephthalate film (PET film). The semiconductor wafer W is, for example, a thin semiconductor wafer having a thickness of 10 to 100 μm. The semiconductor wafer W may be single crystal silicon, polycrystal silicon, various ceramics, or a compound semiconductor such as gallium arsenide.

As shown in FIGS. 7A and 7B, the film 8 is attached so that the adhesive layer 20A is in contact with one surface of the semiconductor wafer W. This step is preferably carried out under temperature conditions of 50 to 120°C, more preferably 60 to 100°C. When the temperature is 50° C. or higher, good adhesion of the semiconductor wafer W to the adhesive layer 20A can be obtained, and when the temperature is 120° C. or lower, the adhesive layer 20A may excessively flow in this step. Suppressed.

As shown in FIG. 7C, the semiconductor wafer W, the adhesive layer 2 and the adhesive layer 20A are diced. As a result, the semiconductor wafer W is diced into individual semiconductor elements Wb. The adhesive layer 20A is also diced into individual adhesive pieces 20P. Examples of the dicing method include a method using a rotary blade or a laser. The semiconductor wafer W may be thinned by grinding the semiconductor wafer W prior to dicing the semiconductor wafer W.

Next, when the pressure-sensitive adhesive layer 2 is, for example, a UV-curable type, the pressure-sensitive adhesive layer 2 is cured by irradiating the pressure-sensitive adhesive layer 2 with ultraviolet rays as shown in FIG. The adhesive force between 2 and the adhesive piece 20P is reduced. After the ultraviolet irradiation, as shown in FIG. 7E, the semiconductor element Wa is separated from each other by expanding the base material layer 1 at room temperature or under cooling conditions, and the semiconductor element Wa is separated from each other, and is pushed up by the needle 42 so that the adhesive layer 2 is removed. The adhesive piece 20P of the laminated body 30 is peeled off, and the laminated body 30 is suctioned and picked up by the suction collet 44. The laminated body 30 thus obtained is used for manufacturing the semiconductor package 100, as shown in FIG.

<Film with integrated dicing and die bonding and its manufacturing method>
The dicing/die-bonding integrated film 8 shown in FIG. 7A and its manufacturing method will be described. As described above, the film 8 includes the base material layer 1 (for example, PET film), the pressure-sensitive adhesive layer 2, and the adhesive layer 20A (adhesive film) in this order. The method for producing the film 8 includes a step of applying a varnish of a thermosetting resin composition containing an epoxy resin or the like on a film (not shown), and an adhesive by heating and drying the applied varnish at 50 to 150° C. It includes a step of forming the layer 20A and a step of attaching the adhesive layer 20A and the pressure-sensitive adhesive layer 2 to each other.

The shear viscosity η ₈₀ of the adhesive layer 20A at 80° C. is 2500 to 4500 Pa·s. When the shear viscosity η ₈₀ is 2500 Pa·s or more, excellent embeddability can be achieved, while when it is 4500 Pa·s or less, bleeding can be suppressed. The lower limit of the shear viscosity η ₈₀ may be 2800 Pa·s or 3000 Pa·s, and the upper limit thereof may be 4300 Pa·s or 4000 Pa·s.

The shear viscosity η ₄₀ of the adhesive layer 20A at 40° C. is preferably 100,000 Pa·s or more. When the shear viscosity η ₄₀ is 100,000 Pa·s or more, bleeding due to the impact of the crimping tool in the initial stage of the thermocompression bonding process can be suppressed. The lower limit of the shear viscosity η ₈₀ may be 120,000 Pa·s or 150,000 Pa·s, and the upper limit thereof is, for example, 800,000 Pa·s, 600,000 Pa·s or 400,000 Pa·s. May be.

The ratio (η ₄₀ /η ₈₀ ) of η _{40 to} η ₈₀ of the adhesive layer 20A is 25 to 200. When η ₄₀ /η ₈₀ is 25 to 200, both excellent embedding property and suppression of bleed can be achieved at a sufficiently high level. The lower limit value of η ₄₀ /η ₈₀ may be 28 or 30, and the upper limit value may be 190 or 170.

The adhesive layer 20A is formed through, for example, a step of applying a varnish containing an epoxy resin, a curing agent, and an elastomer on a film, and a step of drying a coating film formed on the film. The varnish may further contain an inorganic filler, a curing accelerator and the like, if necessary. The varnish can be prepared by mixing or kneading materials such as epoxy resin in a solvent. Mixing or kneading can be performed by using an ordinary stirrer, a raker, a disperser such as a three-roll mill, a ball mill and the like, and appropriately combining these. The details of the varnish will be described later.

The film to which the varnish is applied is not particularly limited, and examples thereof include polyester film, polypropylene film (OPP film and the like), polyethylene terephthalate film, polyimide film, polyetherimide film, polyether naphthalate film, methylpentene film. To be

As a method for applying the varnish to the film, a known method can be used, and examples thereof include a knife coating method, a roll coating method, a spray coating method, a gravure coating method, a bar coating method and a curtain coating method. The heating and drying conditions may be such that the solvent used is sufficiently volatilized, and for example, heating at 50 to 150° C. for 1 to 30 minutes can be performed. The heat drying may be carried out by gradually raising the temperature within the range of 50 to 150°C. By evaporating the solvent contained in the varnish by heating and drying, a laminated film of the film and the adhesive layer 20A can be obtained.

The film 8 can be obtained by bonding the laminated film obtained as described above and the dicing film (a laminated body of the base material layer 1 and the pressure-sensitive adhesive layer 2). Examples of the base layer 1 include plastic films such as polytetrafluoroethylene film, polyethylene terephthalate film, polyethylene film, polypropylene film, polymethylpentene film, and polyimide film. Further, the base material layer 1 may be subjected to surface treatment such as primer coating, UV treatment, corona discharge treatment, polishing treatment, and etching treatment, if necessary. The pressure-sensitive adhesive layer 2 may be a UV curable type or a pressure sensitive type. As the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer 2, a pressure-sensitive adhesive that has been conventionally used for a dicing film may be used. The thickness of the pressure-sensitive adhesive layer 2 is, for example, from 60 to 200 μm, and may be from 70 to 170 μm, from the viewpoint of economy and handleability of the film.

<Varnish for forming adhesive layer>
The varnish for forming the adhesive layer 20A will be described in detail. The adhesive piece 20P is an individual piece of the adhesive layer 20A, and both are made of the same thermosetting resin composition. The adhesive layer 20A and the adhesive piece 20P are in a semi-cured (B stage) state because they have undergone heat treatment for volatilizing the solvent, and are in a completely cured product (C stage) state by the subsequent curing treatment.

As described above, the varnish for forming the adhesive layer contains the epoxy resin, the curing agent, and the elastomer, and further contains the inorganic filler, the curing accelerator, and the like, if necessary. The solvent for preparing the varnish is not limited as long as it can uniformly dissolve, knead or disperse the above components, for example, acetone, methyl ethyl ketone, methyl isobutyl ketone, a ketone solvent such as cyclohexanone, dimethylformamide, dimethyl. Acetamide, N-methylpyrrolidone, toluene, xylene can be used. It is preferable to use methyl ethyl ketone or cyclohexanone since the drying speed is fast and the price is low.

(Epoxy resin)
The structure of the epoxy resin is not particularly limited, but those having an alicyclic structure are preferable from the viewpoint of compatibility. The content of the epoxy resin having an alicyclic structure is, for example, 40 to 20% by mass, 20 to 10% by mass or 10 to 5% by mass based on the total mass of the epoxy resin contained in the adhesive layer 20A. May be. From the viewpoint of setting the shear viscosity η ₄₀ of the adhesive layer 20A at 40° C. to a predetermined value or more, the content of the epoxy resin which is liquid at 25° C. is 40% by mass based on the total mass of the epoxy resin contained in the adhesive layer 20A. It is preferably less than 30% by mass, more preferably less than 30% by mass, and may be less than 14% by mass or less than 9% by mass.

Commercially available epoxy resins include, for example, dicyclopentadiene type epoxy resins HP-7200L (manufactured by DIC Corporation), HP-7200 (manufactured by DIC Corporation), XD-1000 (manufactured by Nippon Kayaku Co., Ltd.), Celoxide 2021P (manufactured by Daicel Corporation), Celoxide 20281 (manufactured by Daicel Corporation), Syna-Epoxy 28 (manufactured by SYANASIA), bis A type epoxy resin YD-128 (manufactured by Mitsubishi Chemical Corporation), bis F type epoxy. Resin EXA-830-CRP (manufactured by DIC Corporation) may be mentioned. These may be used alone or in combination of two or more.

Aromatic epoxy resins may be used as thermosetting resins. Examples of the aromatic epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol F novolac type epoxy resin. Resin, stilbene type epoxy resin, epoxy resin containing triazine skeleton, epoxy resin containing fluorene skeleton, triphenolphenolmethane type epoxy resin, biphenyl type epoxy resin, xylylene type epoxy resin, biphenylaralkyl type epoxy resin, naphthalene type epoxy resin, polyfunctional Examples thereof include diglycidyl ether compounds of polycyclic aromatic compounds such as phenols and anthracenes. These may be used alone or in combination of two or more.

(Curing agent)
Examples of the curing agent include phenolic resins, ester compounds, aromatic amines, aliphatic amines, and acid anhydrides. Of these, a phenol resin is preferable and there is no particular limitation from the viewpoint of reactivity and stability over time. From the viewpoint of setting the shear viscosity η ₄₀ at 40° C. of the adhesive layer high and the shear viscosity η ₈₀ at 80° C. low, it is preferable to use a phenol resin having a softening point of more than 40° C. and less than 60° C. The softening point here means a value measured by the ring and ball method.

Commercially available phenolic resins include, for example, Phenolite KA and TD series manufactured by DIC Corporation, Milex XLC-series and XL series manufactured by Mitsui Chemicals, Inc. (for example, Milex XLC-LL), and Air Water (stock). HE series (for example, HE100C-30) manufactured by Meiwa Kasei Co., Ltd., and MEHC-7800 series (for example, MEHC-7800-4S) manufactured by Meiwa Kasei Co., Ltd. These may be used alone or in combination of two or more. From the viewpoint of heat resistance, the water absorption rate after being put in a constant temperature and humidity tank of 85° C. and 85% RH for 48 hours is 2% by mass or less, and the heating mass reduction rate at 350° C. measured by a thermogravimetric analyzer (TGA). It is preferable that the (temperature rising rate: 5° C./min, atmosphere: nitrogen) is less than 5 mass %.

From the viewpoint of curability, the epoxy resin and the phenol resin are blended so that the equivalent ratio of the epoxy equivalent and the hydroxyl equivalent is preferably 0.30/0.70 to 0.70/0.30, and more preferably 0. 35/0.65 to 0.65/0.35, more preferably 0.40/0.60 to 0.60/0.40, and particularly preferably 0.45/0.55 to 0.55/0. 45. When the compounding ratio is within the above range, it is easy to achieve both a curability and a fluidity at sufficiently high levels.

(Elastomer)
Examples of the elastomer include acrylic resin, polyester resin, polyamide resin, polyimide resin, silicone resin, polybutadiene, acrylonitrile, epoxy-modified polybutadiene, maleic anhydride-modified polybutadiene, phenol-modified polybutadiene and carboxy-modified acrylonitrile.

From the viewpoint of solubility and fluidity in a solvent, an acrylic resin is preferable as the elastomer, and further obtained by polymerizing a functional monomer having an epoxy group or a glycidyl group such as glycidyl acrylate or glycidyl methacrylate as a crosslinkable functional group. An acrylic resin such as an epoxy group-containing (meth)acrylic copolymer is more preferable. Among the acrylic resins, the epoxy group-containing (meth)acrylic acid ester copolymer and the epoxy group-containing acrylic rubber are preferable, and the epoxy group-containing acrylic rubber is more preferable. The epoxy group-containing acrylic rubber is a rubber having an epoxy group, which is mainly composed of an acrylic ester and is mainly composed of a copolymer such as butyl acrylate and acrylonitrile or a copolymer such as ethyl acrylate and acrylonitrile. The acrylic resin may have not only an epoxy group but also a crosslinkable functional group such as an alcoholic or phenolic hydroxyl group and a carboxyl group.

Commercially available products of acrylic resin are SG-70L, SG-708-6, WS-023 EK30, SG-280 EK23, SG-P3 manufactured by Nagase Chemtech Co., Ltd. (product name, acrylic rubber, weight) Average molecular weight: 800,000, Tg: 12° C., solvent is cyclohexanone, etc.

The glass transition temperature (Tg) of the acrylic resin is preferably -50 to 50°C, more preferably -30 to 30°C. The weight average molecular weight (Mw) of the acrylic resin is preferably 100,000 to 3,000,000, more preferably 500,000 to 2,000,000. By blending an acrylic resin having an Mw in this range with a thermosetting resin composition, the thermosetting resin composition can be easily formed into a film, and the strength, flexibility, and tackiness of the film can be appropriately controlled. It's easy to do. In addition to this, both reflowability and embedding property tend to be improved. Here, Mw means a value measured by gel permeation chromatography (GPC) and converted using a calibration curve based on standard polystyrene. By using an acrylic resin having a narrow molecular weight distribution, an adhesive layer having excellent embedding properties and high elasticity tends to be formed.

The amount of the acrylic resin contained in the adhesive layer 20A is preferably 20 to 200 parts by mass, more preferably 30 to 100 parts by mass, based on 100 parts by mass of the total amount of the epoxy resin and the epoxy resin curing agent. .. Within this range, control of fluidity during molding, handling at high temperature, and embedding property can be further improved.

(Inorganic filler)
Examples of the inorganic filler include aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, aluminum nitride, aluminum borate whiskers, boron nitride and crystallinity. Examples thereof include silica and amorphous silica. These may be used alone or in combination of two or more. From the viewpoint of improving the thermal conductivity of the adhesive layer 20A, it is preferable to contain aluminum oxide, aluminum nitride, boron nitride, crystalline silica or amorphous silica as the inorganic filler. From the viewpoint of adjusting the melt viscosity of the adhesive layer 20A and imparting thixotropic properties to the adhesive composition, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, Preference is given to using magnesium oxide, aluminum oxide, crystalline silica or amorphous silica.

The average particle size of the inorganic filler is preferably 0.005 μm to 0.5 μm, more preferably 0.05 to 0.3 μm, from the viewpoint of improving adhesiveness. The surface of the inorganic filler is preferably chemically modified from the viewpoint of compatibility with a solvent and a resin component and adhesive strength. Suitable materials for chemically modifying the surface include silane coupling agents. Examples of the functional group of the silane coupling agent include vinyl group, acryloyl group, epoxy group, mercapto group, amino group, diamino group, alkoxy group and ethoxy group.

From the viewpoint of controlling the fluidity and breakability of the adhesive layer 20A, and the tensile modulus and adhesive strength after curing, the content of the inorganic filler is 10 to 90 relative to 100 parts by mass of the resin component of the adhesive layer 20A. The amount is preferably parts by mass, more preferably 10 to 50 parts by mass. When the content of the inorganic filler is 10 parts by mass or more, the dicing property of the adhesive layer 20A is likely to be improved, and sufficient adhesive force is easily exhibited after curing. On the other hand, when the content of the inorganic filler is 90 parts by mass or less, it is easy to secure sufficient fluidity of the adhesive layer 20A, and it is possible to prevent the elastic modulus after curing from becoming excessively high.

(Curing accelerator)
Examples of the curing accelerator include imidazoles and their derivatives, organic phosphorus compounds, secondary amines, tertiary amines, and quaternary ammonium salts. From the viewpoint of appropriate reactivity, imidazole compounds are preferable. Examples of the imidazoles include 2-methylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole and the like. These may be used alone or in combination of two or more.

The content of the curing accelerator in the adhesive layer 20A is preferably 0.04 to 3 parts by mass, more preferably 0.04 to 0.2 part by mass, based on 100 parts by mass of the total of the epoxy resin and the epoxy resin curing agent. .. When the addition amount of the curing accelerator is within this range, both curability and reliability can be achieved.

Hereinafter, the present disclosure will be described in more detail with reference to examples, but these examples do not limit the present invention.

(Examples 1-5 and Comparative Examples 1-2)
The following materials were mixed in the mixing ratios (parts by mass) shown in Tables 1 and 2 to prepare varnishes. Cyclohexanone was used as the solvent, and the solid content ratio of the varnish was 40% by mass. The varnish was filtered with a 100-mesh filter and vacuum degassed. As a film to which the varnish was applied, a polyethylene terephthalate (PET) film (thickness 38 μm) subjected to a mold release treatment was prepared. The varnish after vacuum defoaming was applied on the surface of the PET film that had been subjected to the release treatment. The applied varnish was heat-dried in two steps of 90° C. for 5 minutes and then 140° C. for 5 minutes. Thus, as the adhesive films according to the examples and the comparative examples, a laminated film including a PET film and a B-stage state (semi-cured state) adhesive layer (thickness 110 μm) formed on the surface thereof was produced. ..

[material]
<Epoxy resin>
・(A1)... XD-1000-2L: (trade name, manufactured by Nippon Kayaku Co., Ltd., cyclopentadiene type epoxy resin, alicyclic structure, solid at 25° C.)
・(A2)...HP-7200L: (trade name, manufactured by DIC Corporation, cyclopentadiene type epoxy resin, alicyclic structure, solid at 25° C.)
・(A3)...YDCN-700-10: (trade name, Nippon Steel & Sumikin Chemical Co., Ltd., cresol novolac type epoxy resin, solid at 25° C.)
・(A4)...EXA-830CRP: (trade name, liquid bisphenol F type epoxy resin manufactured by DIC Corporation, liquid at 25° C.)
<Curing agent>
・(B1)... MEHC-7841-4S: (trade name, manufactured by Meiwa Kasei Co., Ltd., phenol aralkyl resin, softening point: 65° C.)
・(B2)... HE-100C-30: (trade name, manufactured by Air Water Co., Ltd., phenyl aralkyl type phenol resin, softening point: 75° C.)
<Elastomer>
-(C1)... SG-P3 solvent modified product (trade name, manufactured by Nagase ChemteX Corporation, acrylic rubber, weight average molecular weight: 800,000, Tg: 12°C, solvent is cyclohexanone)
-(C2)... SG-708-6: (Sample name, manufactured by Nagase Chemtex Co., Ltd., acrylic rubber, weight average molecular weight 700,000)
<Inorganic filler>
SC2050-HLG: (trade name, manufactured by Admatechs Co., Ltd., silica filler dispersion, average particle size 0.50 μm)
<Curing accelerator>
・Curazole 2PZ-CN: (trade name, 1-cyanoethyl-2-phenylimidazole manufactured by Shikoku Chemicals Co., Ltd.)

[Evaluation of adhesive layer]
Shear viscosity, embeddability and bleed were evaluated for the adhesive layers according to the examples and comparative examples.

<Measurement of shear viscosity>
The adhesive layer (thickness 110 μm) was cut into a predetermined size to prepare four adhesive pieces. A sample having a thickness of 440 μm was prepared by laminating the four pieces of adhesive on a hot plate at 60° C. using a rubber roll. This sample was punched with a punch having a diameter of 9 mm, and the shear viscosity was measured under the following conditions using a shear viscometer (manufactured by TA: trade name ARES-G2). The results are shown in Tables 1 and 2.
・Measurement frequency: 10Hz
・Raising rate: 10°C/min ・Measuring temperature: 35-130°C
・Axial force: 100gf

<Embedding evaluation>
First, a structure used for evaluation of embedding property, including a substrate and a first semiconductor element mounted on the surface thereof, was prepared as follows. That is, a film adhesive HR9004-10 (trade name, manufactured by Hitachi Chemical Co., Ltd., thickness 10 μm) was attached to a semiconductor wafer (diameter: 8 inches, thickness: 50 μm) at 70° C. A semiconductor element with adhesive (first semiconductor element) was obtained by dicing the semiconductor wafer and the film adhesive into a 4.8×5.7 mm square. The semiconductor element with the adhesive was pressure-bonded to the evaluation substrate under the conditions of 120° C., 0.20 MPa, and 2 seconds. A substrate (total thickness: 260 μm) having a surface coated with a solder resist AUS308 (trade name, manufactured by Taiyo Nippon Sanso Co., Ltd.) was used as an evaluation substrate.

On the other hand, the adhesive layers (thickness 110 μm) according to the examples and the comparative examples were attached to semiconductor wafers (diameter: 8 inches, thickness 100 μm) at 70° C. By dicing the semiconductor wafer and the adhesive layer into 8.5×12 mm square, a semiconductor element with an adhesive piece (second semiconductor element) was obtained.

A semiconductor element with an adhesive piece (second semiconductor element) was pressure-bonded to the position where the first semiconductor element was mounted in the structure. The pressure bonding conditions were 120° C., 0.20 MPa, and 1.5 seconds. The alignment was performed so that the first semiconductor element was embedded in the central position of the adhesive piece. The evaluation sample thus prepared was observed for the presence or absence of voids with an ultrasonic digital image diagnostic apparatus (Insight Co., Ltd., probe: 75 MHz). If voids were observed, the voids per unit area were observed. Area was calculated, and the results of these analyzes were evaluated as embeddability. The evaluation criteria are as follows. The results are shown in Tables 1 and 2.
A: No void was observed.
B: Voids were observed, but the ratio was less than 5 area %.
C: Voids were observed, and the ratio was 5 area% or more.

<Bleed evaluation>
First, a structure used for evaluation of bleeding, including a substrate and a first semiconductor element mounted on the surface thereof, was prepared as follows. That is, a film adhesive HR9004-10 (trade name, manufactured by Hitachi Chemical Co., Ltd., thickness 10 μm) was attached to a semiconductor wafer (diameter: 8 inches, thickness: 50 μm) at 70° C. A semiconductor element with adhesive (first semiconductor element) was obtained by dicing the semiconductor wafer and the film-like adhesive into a 2.1×4.8 mm square. The semiconductor element with the adhesive was pressure-bonded to the evaluation substrate under the conditions of 120° C., 0.20 MPa and 2 seconds. A substrate (total thickness: 260 μm) having a surface coated with a solder resist AUS308 (trade name, manufactured by Taiyo Nippon Sanso Co., Ltd.) was used as an evaluation substrate.

On the other hand, the adhesive layers (thickness 110 μm) according to the examples and the comparative examples were attached to semiconductor wafers (diameter: 8 inches, thickness 100 μm) at 70° C. By dicing the semiconductor wafer and the adhesive layer into a 6×12.7 mm square, a semiconductor element with an adhesive piece (second semiconductor element) was obtained.

▽A semiconductor element with an adhesive piece (second semiconductor element) was pressure-bonded to the position where the first semiconductor element was mounted in the above structure. The pressure bonding conditions were 120° C., 0.20 MPa and 1.5 seconds. The alignment was performed so that the first semiconductor element was embedded in the central position of the adhesive layer. The evaluation sample thus produced was observed with a microscope to measure the maximum distance (bleed amount) of the resin composition protruding from the end of the second semiconductor element. The results are shown in Tables 1 and 2.

(Reference example)
A reproduction test of Example 2 of Patent Document 2 (temperature at which shear viscosity becomes 5000 Pa·s: 63° C.) was performed. That is, the same material as that used in Example 2 of Patent Document 2 was used, and a film adhesive according to Reference Example was produced in the same manner as Example 2 of Patent Document 2.

The temperature at which the film-like adhesive according to the reference example had a shear viscosity of 5000 Pa·s was 62°C. Further, the shear viscosity η ₄₀ at 40° C. of the film adhesive according to the reference example is 70921 Pa·s, the shear viscosity η _{80 at} 80° C. is 1568 Pa·s, and the value of η ₄₀ /η ₈₀ is 45. It was

According to the present disclosure, an adhesive film including an adhesive layer made of a thermosetting resin composition, which has excellent embeddability to a semiconductor element and can sufficiently suppress bleeding in a thermocompression bonding process. A film is provided. According to the present disclosure, there is provided a dicing/die-bonding integrated film including the adhesive layer of the adhesive film, and a method for manufacturing a semiconductor package using the film.

2... Adhesive layer, 8... Dicing/die bonding integrated film, 10... Substrate, 20... First sealing layer (cured product of adhesive piece), 20A... Adhesive layer (adhesive film), 20P... Adhesion Agent piece, 30... Laminated body, 50... Structure, 100... Semiconductor package, W... Wafer, Wa... First semiconductor element, Wb... Second semiconductor element

Claims

An adhesive film comprising an adhesive layer made of a thermosetting resin composition,
When the shear viscosity of the adhesive layer at 40° C. is η 40, and the shear viscosity of the adhesive layer at 80° C. is η 80 ,
η 80 is 2500 to 4500 Pa·s,
ratio of eta 40 for η 80 (η 40 / η 80 ) is 25 to 200, the adhesive film.
The adhesive layer is used to embed a first semiconductor element on a substrate and mount a second semiconductor element on the substrate in a manufacturing process of a chip-embedded semiconductor package. The adhesive film described.
The adhesive film according to claim 1 or 2, wherein η 40 is 100,000 Pa·s or more.
The adhesive film according to any one of claims 1 to 3, wherein the thermosetting resin composition contains a phenol resin having a softening point of more than 40°C and less than 70°C.
Adhesion according to any one of claims 1 to 4, wherein the content of the epoxy resin which is liquid at 25°C is less than 40% by mass based on the total mass of the epoxy resin contained in the thermosetting resin composition. the film.
The adhesive film according to any one of claims 1 to 5, wherein the thermosetting resin composition contains an epoxy resin having an alicyclic structure, a curing agent, and an elastomer.
The adhesive film according to claim 6, wherein the curing agent is a phenol resin.
The adhesive film according to claim 6 or 7, wherein the elastomer is an acrylic resin.
The adhesive film according to any one of claims 1 to 8, wherein the thermosetting resin composition contains an inorganic filler.
The adhesive film according to any one of claims 1 to 9, wherein the thermosetting resin composition contains a curing accelerator.
The adhesive film according to any one of claims 1 to 10, comprising a base film provided on one surface of the adhesive layer.
The adhesive layer of the adhesive film according to any one of claims 1 to 11,
A pressure-sensitive adhesive layer provided on one surface of the adhesive layer,
A film with integrated dicing and die bonding.
The integrated dicing/die bonding film according to claim 12, further comprising a protective film provided so as to cover the adhesive layer.
A method for manufacturing a semiconductor package using the dicing/die-bonding integrated film according to claim 12 or 13.
Preparing a structure comprising a substrate and a first semiconductor element mounted on the surface of the substrate;
Bonding the adhesive layer of the dicing/die-bonding integrated film according to claim 12 or 13 to a wafer;
Separating the wafer bonded to the adhesive layer into a plurality of second semiconductor elements,
A step of picking up from the pressure-sensitive adhesive layer a laminate including the adhesive piece formed by dividing the adhesive layer into individual pieces and the second semiconductor element;
Thermocompression-bonding the laminated body to the substrate so that the first semiconductor element is embedded in the adhesive piece;
Curing the adhesive piece by heat treatment,
A method of manufacturing a chip-embedded semiconductor package, comprising: