JP7322897B2 - Adhesive film, dicing/die bonding integrated film, and method for manufacturing semiconductor package - Google Patents

Description

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

Conventionally, in the manufacturing process of semiconductor devices, silver paste has been mainly used for bonding semiconductor elements and supporting members. However, with the recent miniaturization and integration of semiconductor elements, problems tend to occur in wire bonding due to protrusion of silver paste or inclination of semiconductor elements. When an adhesive composition is used instead of the silver paste, there are problems such as difficulty in making the thickness of the adhesive layer sufficiently uniform and the generation of voids in the adhesive layer.

In recent years, film-like adhesives have come to be used for bonding semiconductor elements and supporting members. For example, Patent Document 1 discloses a sheet for both dicing and die bonding, which includes a substrate, a wire-embedded layer, and an insulating layer. By performing dicing in a state in which the insulating layer of this sheet and the wafer are bonded together, the semiconductor wafer and the wire-embedded layer are separated into individual pieces. The semiconductor element and the support member are joined by thermocompression bonding the semiconductor element to the support member through the wire embedding layer.

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

JP-A-2007-53240 JP 2014-175459 A

As the size of semiconductor elements (chips) becomes smaller, there is a tendency for the pressing force per unit area to become excessively large in the thermocompression bonding process in the manufacturing process of semiconductor packages. As a result, there is a risk that the adhesive composition constituting the adhesive film will protrude from the semiconductor element (hereinafter referred to as "bleeding"), or that the adhesive film will be excessively crushed to cause electrical failure. In particular, if the composition of the FOD is changed to improve the fluidity in the thermocompression bonding process in order to improve the embedability of the adhesive film (FOD) used in the manufacture of chip-embedded semiconductor packages, bleeding becomes noticeable. . For example, the adhesive composition that squeezes out may climb up to the top surface of the semiconductor device, which can cause electrical failures or wire bonding failures. In other words, conventional adhesive films cannot always achieve both excellent embeddability in a semiconductor element and suppression of bleeding in the manufacturing process of a chip-embedded 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 embedding properties in a semiconductor element and can sufficiently suppress bleeding in a thermocompression bonding process. 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 same.

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

The present inventors have studied the mechanism of bleeding occurring 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 thought that bleeding mainly occurs as the adhesive layer is gradually crushed by the pressing force applied to the adhesive layer. However, it has been found that the main cause of bleeding is the impact when the tool for applying the pressing force descends and comes into contact with the object. The adhesive film according to the present disclosure is designed based on this knowledge, and the shear viscosity _η40 at 40°C of the adhesive layer is set to be 25 to 200 times the shear viscosity _η80 at 80°C. By increasing the shear viscosity η ₄₀ at 40° C., the impact during the initial stage of the thermocompression bonding process, that is, when the tool is lowered and touches the object and the adhesive layer is not sufficiently heated, can sufficiently suppress bleeding caused by On the other hand, when the adhesive layer has a shear viscosity η ₈₀ at 80° C. of 2500 to 4500 Pa·s, excellent embedding properties can be achieved.

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

In order for the adhesive layer to satisfy the above conditions for _η40 and _η80 , for example, one or more of the following items regarding the composition of the thermosetting resin composition that constitutes the adhesive layer It is sufficient to adopt the items of
- The thermosetting resin composition contains a phenolic resin having a softening point of more than 40°C and less than 70°C.
- The content of the epoxy resin that is liquid at 25°C (based on the total mass of the epoxy resin contained in the thermosetting resin composition) is less than 40% by mass.
- The thermosetting resin composition contains an epoxy resin having an alicyclic structure, a curing agent (eg, phenolic resin), and an elastomer (eg, 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. Alternatively, a dicing/die-bonding integrated film may be configured by combining the adhesive layer and the pressure-sensitive adhesive layer. That is, the dicing and 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 optionally , a protective film may be provided to cover the adhesive layer.

The present disclosure provides a method of manufacturing a semiconductor package using the dicing/die bonding integrated film. For example, a chip-embedded semiconductor package is manufactured through the following steps.
- providing a structure comprising a substrate and a first semiconductor device mounted on a 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 singulating the wafer bonded to the adhesive layer into a plurality of second semiconductor elements.
A step of picking up from the adhesive layer a laminate including the adhesive pieces and the second semiconductor element formed by singulating the adhesive layer.
• thermocompression bonding the laminate to the substrate such that the first semiconductor element is embedded in the adhesive strip.
- hardening the adhesive strips by heat treatment;

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

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

FIG. 1 is a cross-sectional view schematically showing an example of a semiconductor package. FIG. 2 is a cross-sectional view schematically showing an example of a laminate composed of an adhesive piece and a second semiconductor element. 3A to 3C are cross-sectional views schematically showing the process of manufacturing the semiconductor package shown in FIG. 4A to 4D are cross-sectional views schematically showing the process of manufacturing the semiconductor package shown in FIG. 5A to 5D are cross-sectional views schematically showing the process of manufacturing the semiconductor package shown in FIG. 6A to 6C are cross-sectional views schematically showing the process of manufacturing the semiconductor package shown in FIG. 7(a) to 7(e) are cross-sectional views schematically showing the process of manufacturing a laminate composed of an adhesive piece and a 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 are denoted by the same reference numerals, and overlapping descriptions are omitted. In addition, unless otherwise specified, positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings. Furthermore, the dimensional ratios of the drawings are not limited to the illustrated ratios. In addition, the description of "(meth)acryl" in this specification means "acryl" and "methacryl" corresponding to it.

<Semiconductor package>
FIG. 1 is a cross-sectional view schematically showing a chip-embedded semiconductor package according to this embodiment. The 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 sealing the first semiconductor element Wa. , a second semiconductor element Wb disposed 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 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 this 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 connected via the first wire 11 to the circuit pattern 10b. The shape of the first semiconductor element Wa in 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 as to cover the entire first semiconductor element Wa and part of the circuit pattern 10b. The shape of the second semiconductor element Wb in 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, 10-170 μm, and may be 20-120 μm. The second semiconductor element Wb is connected to the circuit pattern 10b via the second wire 12 and sealed with the second sealing layer 40 .

The first sealing layer 20 consists of a cured adhesive piece 20P (see FIG. 2). Note that, as shown in FIG. 2, the adhesive piece 20P and the second semiconductor element Wb are substantially the same size. The laminate 30 shown in FIG. 2 is composed of an adhesive piece 20P and a second semiconductor element Wb, and is also called an adhesive-attached semiconductor element. The laminated body 30 is produced through a dicing process and a pick-up process, as will be described later (see FIG. 7).

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

Next, as shown in FIG. 4, the adhesive piece 20P of the laminate 30 prepared separately is pressed against the substrate 10. Next, as shown in FIG. As a result, the first semiconductor element Wa and the first wires 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, etc. For example, it may be 20 to 200 μm, and may be 30 to 200 μm or 40 to 150 μm. . By setting the thickness of the adhesive piece 20P within the above range, a sufficient distance (distance G in FIG. 5) between the first semiconductor element Wa and the second semiconductor element Wb can be ensured. The distance G is, for example, preferably 50 μm or more, and may be 50-75 μm or 50-80 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 adhesive piece 20P (first sealing layer 20) (see FIG. 6). The curing treatment of the adhesive piece 20P may be performed under 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 semiconductor package 100 is completed by sealing the second semiconductor element Wb with the second sealing layer 40. (see Figure 1).

<Method for producing semiconductor element with adhesive>
An example of a method for manufacturing the laminate 30 (semiconductor element with adhesive) shown in FIG. 2 will be described with reference to FIGS. 7(a) to 7(e). First, a dicing/die bonding integrated film 8 (hereinafter sometimes referred to as "film 8") is arranged in a predetermined device (not shown). The film 8 comprises a substrate layer 1, an adhesive layer 2, and an 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 with a thickness of 10-100 μm. The semiconductor wafer W may be monocrystalline silicon, polycrystalline silicon, various ceramics, or compound semiconductors such as gallium arsenide.

As shown in FIGS. 7A and 7B, the film 8 is attached to one surface of the semiconductor wafer W so that the adhesive layer 20A is in contact therewith. This step is preferably carried out at a temperature of 50-120°C, more preferably 60-100°C. When the temperature is 50° C. or higher, good adhesion between the semiconductor wafer W and the adhesive layer 20A can be obtained. Suppressed.

As shown in FIG. 7(c), the semiconductor wafer W, the adhesive layer 2 and the adhesive layer 20A are diced. As a result, the semiconductor wafer W is separated into individual semiconductor elements Wb. The adhesive layer 20A is also singulated to form adhesive pieces 20P. A dicing method includes a method using a rotary blade or a laser. In addition, the semiconductor wafer W may be thinned by grinding the semiconductor wafer W prior to the dicing of the semiconductor wafer W. FIG.

Next, when the adhesive layer 2 is, for example, a UV-curing type, the adhesive layer 2 is cured by irradiating the adhesive layer 2 with ultraviolet rays, as shown in FIG. 2 and the adhesive strip 20P. After the ultraviolet irradiation, as shown in FIG. 7(e), the semiconductor elements Wa are separated from each other by expanding the substrate layer 1 under room temperature or cooling conditions, and pushed up with a needle 42 to separate them from the pressure-sensitive adhesive layer 2. The adhesive pieces 20P of the laminate 30 are peeled off, and the laminate 30 is sucked by the suction collet 44 and picked up. The laminate 30 thus obtained is used for manufacturing a semiconductor package 100 as shown in FIG.

<Dicing/die-bonding integrated film 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 substrate layer 1 (for example, PET film), the adhesive layer 2, and the adhesive layer 20A (adhesive film) in this order. The method of manufacturing the film 8 includes the steps of applying a varnish of a thermosetting resin composition containing an epoxy resin or the like on a film (not shown), and drying the applied varnish by heating at 50 to 150 ° C. to form an adhesive. A step of forming the layer 20A and a step of bonding the adhesive layer 20A and the adhesive layer 2 are included.

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

The shear viscosity _η40 of the adhesive layer 20A at 40° C. is preferably 100,000 Pa·s or more. When the shear viscosity _η40 is 100,000 Pa·s or more, it is possible to suppress bleeding caused by the impact of the crimping tool in the initial stage of the thermocompression bonding process. The lower limit of shear viscosity η ₈₀ may be 120,000 Pa s or 150,000 Pa s, and the upper limit is, for example, 800,000 Pa s, 600,000 Pa s, or 400,000 Pa s. may

The ratio of _{η40 to η80 of} the adhesive layer 20A ( _η40 / _η80 ) is 25-200. When η ₄₀ /η ₈₀ is 25 to 200, both excellent embeddability and suppression of bleeding can be achieved at a sufficiently high level. The lower limit of η ₄₀ /η ₈₀ may be 28 or 30, and the upper limit may be 190 or 170.

The adhesive layer 20A is formed through, for example, a step of coating a film with a varnish containing an epoxy resin, a curing agent, and an elastomer, and a step of drying the coating film formed on the film. The varnish may further contain an inorganic filler, a curing accelerator, etc., if necessary. Varnishes can be prepared by mixing or kneading materials such as epoxy resins in a solvent. Mixing or kneading can be carried out by using an ordinary dispersing machine such as a stirrer, a kneading machine, a triple roll, a ball mill, or the like, and by appropriately combining these. Details of the varnish will be described later.

The film to which the varnish is applied is not particularly limited. be done.

A known method can be used as a method for applying a varnish to a film, 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 drying by heating may be carried out under conditions that sufficiently volatilize the solvent used, for example, at 50 to 150° C. for 1 to 30 minutes. Heat drying may be carried out by stepwise raising the temperature within the range of 50 to 150°C. By volatilizing 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 together the laminated film obtained as described above and the dicing film (laminated body of the substrate layer 1 and the pressure-sensitive adhesive layer 2). Examples of the substrate layer 1 include plastic films such as polytetrafluoroethylene film, polyethylene terephthalate film, polyethylene film, polypropylene film, polymethylpentene film, and polyimide film. Further, the substrate layer 1 may be subjected to surface treatment such as primer coating, UV treatment, corona discharge treatment, polishing treatment, etching treatment, etc., as necessary. The adhesive layer 2 may be UV curable or pressure sensitive. As the adhesive constituting the adhesive layer 2, an adhesive conventionally used for dicing films may be used. The thickness of the pressure-sensitive adhesive layer 2 is, for example, 60 to 200 μm, and may be 70 to 170 μm, from the viewpoint of economy and film handling.

<Varnish for forming adhesive layer>
A varnish for forming the adhesive layer 20A will be described in detail. The adhesive piece 20P is obtained by dividing the adhesive layer 20A into individual pieces, 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 a heat treatment for volatilizing the solvent, and are in a fully cured (C stage) state by the subsequent curing treatment.

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

(Epoxy resin)
There are no particular restrictions on the structure of the epoxy resin, but those having an alicyclic structure are preferred 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 From the viewpoint of making the shear viscosity _η40 of the adhesive layer 20A at 40° C. equal to or higher than a predetermined value, the content of the epoxy resin that is liquid at 25° C. is 40% by mass based on the total mass of the epoxy resins 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 resin 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-Epoxy28 (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) can be mentioned. These may be used individually by 1 type, and may use 2 or more types together.

Aromatic epoxy resins may also be used as thermosetting resins. Examples of aromatic epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, bisphenol A novolak type epoxy resin, bisphenol F novolak type epoxy resin. Resins, stilbene type epoxy resins, triazine skeleton-containing epoxy resins, fluorene skeleton-containing epoxy resins, triphenol phenol methane type epoxy resins, biphenyl type epoxy resins, xylylene type epoxy resins, biphenyl aralkyl type epoxy resins, naphthalene type epoxy resins, polyfunctional Examples include diglycidyl ether compounds of polycyclic aromatics such as phenols and anthracene. These may be used individually by 1 type, and may use 2 or more types together.

(curing agent)
Curing agents include, for example, phenolic resins, ester compounds, aromatic amines, aliphatic amines and acid anhydrides. Of these, phenol resins are preferred from the viewpoint of reactivity and stability over time, and there is no particular limitation. From the viewpoint of setting the shear viscosity _η40 at 40°C of the adhesive layer high and setting the shear viscosity _η80 at 80°C low, it is preferable to use a phenolic resin having a softening point of more than 40°C and less than 60°C. In addition, the softening point here means the value measured by the ring and ball method.

Commercially available phenolic resins include, for example, DIC Corporation's Phenolite KA and TD series, Mitsui Chemicals Inc.'s Millex XLC-series and XL series (eg, Millex XLC-LL), Air Water Inc. ) manufactured by HE series (eg, HE100C-30), MEHC-7800 series manufactured by Meiwa Kasei Co., Ltd. (eg, MEHC-7800-4S). These may be used individually by 1 type, and may use 2 or more types together. From the viewpoint of heat resistance, the water absorption rate after being placed in a constant temperature and humidity chamber at 85 ° C. and 85% RH for 48 hours is 2% by mass or less, and the heating mass reduction rate at 350 ° C. measured with a thermogravimetric analyzer (TGA). (Temperature increase rate: 5°C/min, atmosphere: nitrogen) is preferably less than 5% by mass.

From the viewpoint of curability, the amount of epoxy resin and phenol resin to be blended is such that the equivalent ratio of epoxy equivalent to hydroxyl group equivalent is preferably 0.30/0.70 to 0.70/0.30, more preferably 0.30/0.70 to 0.70/0.30. 35/0.65 to 0.65/0.35, more preferably 0.40/0.60 to 0.60/0.40, particularly preferably 0.45/0.55 to 0.55/0.35. is 45. When the blending ratio is within the above range, both curability and fluidity can be easily achieved at sufficiently high levels.

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

Acrylic resins are preferred as elastomers from the viewpoint of solubility in solvents and fluidity, and are obtained by polymerizing functional monomers having epoxy groups or glycidyl groups as crosslinkable functional groups, such as glycidyl acrylate or glycidyl methacrylate. Acrylic resins such as epoxy group-containing (meth)acrylic copolymers are more preferable. Among acrylic resins, epoxy group-containing (meth)acrylic acid ester copolymers and epoxy group-containing acrylic rubbers are preferable, and epoxy group-containing acrylic rubbers are more preferable. Epoxy-group-containing acrylic rubber is a rubber having an epoxy group, which is mainly composed of an acrylic acid 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 epoxy groups but also crosslinkable functional groups such as alcoholic or phenolic hydroxyl groups and carboxyl groups.

Commercially available acrylic resins include SG-70L, SG-708-6, WS-023 EK30, SG-280 EK23, SG-P3 manufactured by Nagase Chemtech Co., Ltd. (trade name, acrylic rubber, weight average molecular weight: 800,000, Tg: 12° C., solvent is cyclohexanone) and the like.

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 with Mw in this range into the 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, both reflowability and embeddability tend to improve. Here, Mw means a value measured by gel permeation chromatography (GPC) and converted using a standard polystyrene calibration curve. By using an acrylic resin with a narrow molecular weight distribution, there is a tendency that an adhesive layer with excellent embedding properties and high elasticity can 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 with respect to the total of 100 parts by mass of the epoxy resin and the epoxy resin curing agent. . Within this range, it is possible to further improve flow control during molding, handleability at high temperatures, and embeddability.

(Inorganic filler)
Inorganic fillers such as 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 crystalline Silica and amorphous silica can be mentioned. These may be used individually by 1 type, and may use 2 or more types together. 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 an 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 the solvent and resin component, and adhesive strength. Silane coupling agents are suitable materials for chemically modifying the surface. Examples of types of functional groups in the silane coupling agent include vinyl groups, acryloyl groups, epoxy groups, mercapto groups, amino groups, diamino groups, alkoxy groups, and ethoxy groups.

From the viewpoint of controlling the fluidity and breakability of the adhesive layer 20A, as well as the tensile modulus and adhesive strength after curing, the content of the inorganic filler is 10 to 90 parts with respect to 100 parts by mass of the resin component of the adhesive layer 20A. It 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 strength is likely to be 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 sufficiently secure the fluidity of the adhesive layer 20A, and it is possible to prevent the elastic modulus from becoming excessively high after curing.

(Curing accelerator)
Curing accelerators include, for example, imidazoles and derivatives thereof, organophosphorus compounds, secondary amines, tertiary amines, and quaternary ammonium salts. An imidazole compound is preferred from the viewpoint of appropriate reactivity. Examples of imidazoles include 2-methylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole and the like. These may be used individually by 1 type, and may use 2 or more types together.

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 parts by mass with respect to the total 100 parts by mass of the epoxy resin and the epoxy resin curing agent. . When the amount of the curing accelerator to be added is within this range, both curability and reliability can be achieved.

The present disclosure will be described in more detail below with reference to examples, but these examples are not intended to limit the present invention.

(Examples 1-5 and Comparative Examples 1-2)
A varnish was prepared by mixing the following materials in the proportions (parts by mass) shown in Tables 1 and 2. Cyclohexanone was used as the solvent, and the solid content of the varnish was 40% by mass. The varnish was filtered through a 100 mesh filter and vacuum defoamed. A release-treated polyethylene terephthalate (PET) film (thickness: 38 μm) was prepared as a film to be coated with varnish. The varnish after vacuum defoaming was applied onto the release-treated surface of the PET film. The applied varnish was dried by heating in two steps, 90° C. for 5 minutes and then 140° C. for 5 minutes. In this way, laminated films each comprising a PET film and a B-stage (semi-cured) adhesive layer (thickness: 110 μm) formed on the surface of the PET film were produced as adhesive films according to Examples and Comparative Examples. .

[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, manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., cresol novolak type epoxy resin, solid at 25 ° C.)
・ (A4) ... EXA-830CRP: (trade name, manufactured by DIC Corporation, liquid bisphenol F type epoxy resin, 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 Inc., phenyl arachyl-type phenolic resin, softening point: 75°C)
<Elastomer>
・(C1) … SG-P3 solvent changed 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 Corporation, 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>
・Curesol 2PZ-CN: (trade name, manufactured by Shikoku Chemical Industry Co., Ltd., 1-cyanoethyl-2-phenylimidazole)

[Evaluation of Adhesive Layer]
The adhesive layers of Examples and Comparative Examples were evaluated for shear viscosity, embedding properties, and bleeding.

<Measurement of shear viscosity>
An adhesive layer (110 μm thick) was cut to size to prepare four adhesive strips. A 440 μm thick sample was prepared by laminating four adhesive strips on a hot plate at 60° C. using rubber rolls. This sample was punched out with a φ9 mm punch, and the shear viscosity was measured under the following conditions using a shear viscometer (trade name: ARES-G2, manufactured by TA). Tables 1 and 2 show the results.
・Measurement frequency: 10Hz
・Temperature increase rate: 10°C/min ・Measurement temperature: 35 to 130°C
・Axial force: 100gf

<Evaluation of Embedability>
First, a structure to be used for evaluation of embeddability, comprising a substrate and a first semiconductor element mounted on the surface thereof, was prepared as follows. Specifically, 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. By dicing the semiconductor wafer and the film adhesive into 4.8×5.7 mm squares, semiconductor elements with adhesive (first semiconductor elements) were obtained. This semiconductor element with an adhesive was press-bonded to an evaluation substrate under conditions of 120° C., 0.20 MPa, and 2 seconds. As a substrate for evaluation, a substrate (total thickness: 260 μm) coated with a solder resist AUS308 (trade name, manufactured by Taiyo Nippon Sanso Corporation) was used.

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

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 crimping conditions were 120° C., 0.20 MPa, and 1.5 seconds. The position was adjusted so that the first semiconductor element was embedded in the central position of the adhesive piece. The evaluation sample prepared in this way is observed for the presence or absence of voids with an ultrasonic digital diagnostic imaging device (manufactured by Insight Corporation, probe: 75 MHz), and if voids are observed, the voids per unit area was calculated, and these analysis results were evaluated as implantability. The evaluation criteria were as follows. Tables 1 and 2 show the results.
A: No voids were observed.
B: Voids were observed, but their proportion was less than 5 area %.
C: Voids were observed and their proportion was 5 area % or more.

<Evaluation of bleeding>
First, a structure to be used for evaluation of bleeding, comprising a substrate and a first semiconductor element mounted on the surface thereof, was prepared as follows. Specifically, 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. By dicing the semiconductor wafer and the film adhesive into 2.1×4.8 mm squares, semiconductor elements with adhesive (first semiconductor elements) were obtained. This semiconductor element with an adhesive was press-bonded to an evaluation substrate under conditions of 120° C., 0.20 MPa, and 2 seconds. As a substrate for evaluation, a substrate (total thickness: 260 μm) coated with a solder resist AUS308 (trade name, manufactured by Taiyo Nippon Sanso Corporation) was used.

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

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 crimping conditions were 120° C., 0.20 MPa, and 1.5 seconds. The position was adjusted so that the first semiconductor element was embedded in the central position of the adhesive layer. The sample for evaluation produced in this way was observed with a microscope, and the maximum distance (bleed amount) of the resin composition protruding from the end of the second semiconductor element was measured. Tables 1 and 2 show the results.

(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, using the same materials as those used in Example 2 of Patent Document 2, a film-like adhesive according to Reference Example was produced in the same manner as in Example 2 of Patent Document 2.

The temperature at which the film adhesive according to the reference example had a shear viscosity of 5000 Pa·s was 62°C. Further, the film-like adhesive according to the reference example had a shear viscosity _η40 at 40°C of 70921 Pa·s, a shear viscosity _η80 of 1568 Pa·s at 80°C, and a value of _η40 / _η80 of 45. rice field.

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

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 (9)

An adhesive film comprising an adhesive layer made of a thermosetting resin composition,
Assuming that the shear viscosity of the adhesive layer at 40°C is _η40 and the shear viscosity of the adhesive layer at 80°C is _η80 ,
η ₈₀ is 2500 to 4500 Pa s,
the ratio of _η40 to η80 ( _η40 / _η80 ) is 25 to 200 _;
The thermosetting resin composition comprises an epoxy resin, a curing agent containing a phenolic resin having a softening point of more than 40 ° C. and less than 70 ° C., an acrylic resin having a weight average molecular weight of 100,000 to 3,000,000, an inorganic filler, and a curing accelerator,
In the thermosetting resin composition, the content of the epoxy resin that 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,
In the thermosetting resin composition, the content of the acrylic resin is 20 to 200 parts by mass per 100 parts by mass of the total mass of the epoxy resin and the curing agent contained in the thermosetting resin composition. can be,
An adhesive film, wherein the content of the inorganic filler in the thermosetting resin composition is 10 to 90 parts by mass with respect to 100 parts by mass of the resin component contained in the thermosetting resin composition. 2. The method of claim 1, wherein the adhesive layer is used to embed a first semiconductor element on a substrate and mount a second semiconductor element to the substrate in a manufacturing process of an embedded chip semiconductor package. Adhesive film as described. 3. The adhesive film according to claim 1, wherein _η40 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 an epoxy resin having an alicyclic structure. The adhesive film according to any one of claims 1 to 4 , comprising a base film provided on one surface of said adhesive layer. The adhesive layer of the adhesive film according to any one of claims 1 to 5 ;
a pressure-sensitive adhesive layer provided on one surface of the adhesive layer;
A dicing and die bonding integrated film. 7. The integrated dicing and die bonding film according to claim 6 , further comprising a protective film provided so as to cover said adhesive layer. A method of manufacturing a semiconductor package using the dicing/die bonding integrated film according to claim 6 or 7 . providing a structure comprising a substrate and a first semiconductor device mounted on a surface of the substrate;
A step of bonding the adhesive layer and the wafer of the dicing/die bonding integrated film according to claim 6 or 7 ;
a step of singulating the wafer bonded to the adhesive layer into a plurality of second semiconductor elements;
a step of picking up from the adhesive layer a laminate including adhesive pieces formed by singulating the adhesive layer and the second semiconductor element;
thermocompression bonding the laminate to the substrate such that the first semiconductor element is embedded in the adhesive strip;
curing the adhesive strip by heat treatment;
A method of manufacturing a chip-embedded semiconductor package, comprising:

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