JP7848546B2 - Adhesive film for semiconductors, dicing and die bonding integrated film, and method for manufacturing semiconductor devices - Google Patents

Description

This disclosure relates to adhesive films for semiconductors, dicing and die bonding integrated films, and methods for manufacturing semiconductor devices.

Stacked Multi-Chip Packages (MCPs), which achieve high capacity through multi-layered semiconductor chips, are becoming widespread. Examples of stacked MCPs include wire-embedded and chip-embedded semiconductor packages. A semiconductor package structure in which wires are embedded by an adhesive film is sometimes referred to as FOW (Film Over Wire). A semiconductor package structure in which semiconductor chips are embedded by an adhesive film is sometimes referred to as FOD (Film Over Die). An example of a semiconductor package employing FOD is one having a controller chip positioned at the bottom and an adhesive film embedding it (see Patent Document 1). In the manufacturing of semiconductor packages with an FOD or FOW structure, it is required that the semiconductor chip or wires are sufficiently embedded by the adhesive film.

Japanese Patent Publication No. 2014-175459

However, conventional adhesive films are highly fluid from the perspective of improving the embedding ability of controller chips, which makes them prone to resin bleeding from the chip edges, and there is still room for improvement. In addition, from the perspective of semiconductor package reliability, the cured properties of adhesive films must suppress defects such as crack formation. To prevent such defects, the cured adhesive film must have sufficient tensile strength.

Therefore, the main objective of this disclosure is to provide a semiconductor adhesive film that can suppress bleeding when embedding semiconductor chips or wires, and that has sufficient fracture strength after curing.

Our inventors have discovered that by combining a predetermined inorganic filler, it is possible to suppress bleeding when embedding semiconductor chips or wires, and furthermore, to improve fracture strength after curing. This led to the completion of the invention described herein.

One aspect of this disclosure relates to an adhesive film for semiconductors. The adhesive film for semiconductors (hereinafter sometimes simply referred to as "adhesive film") contains a thermosetting component, an elastomer, a first inorganic filler, and a second inorganic filler. The first inorganic filler and the second inorganic filler satisfy all of the following conditions.
The average particle size of the first inorganic filler is 300 to 1000 nm.
The average particle size of the second inorganic filler is 0.05 to 0.70 times that of the average particle size of the first inorganic filler.
The total content of the first and second inorganic fillers is 30 to 60% by mass, based on the total amount of adhesive film.

One embodiment of the adhesive film may have a thickness of 60 to 150 μm. In this case, the adhesive film may be an FOD adhesive film used to bond semiconductor chips to a substrate while embedding other semiconductor chips.

Other embodiments of the adhesive film may have a thickness of 25 to 80 μm. In this case, the adhesive film may be a FOW adhesive film used to bond to another semiconductor chip while embedding part or all of the wires connected to that other semiconductor chip.

The elastomer content may be 15 to 35% by mass, based on the total amount of adhesive film.

The content of the thermosetting component may be 10 to 40% by mass, based on the total amount of the adhesive film.

The thermosetting component may include a liquid epoxy resin that is liquid at 30°C. In this case, the liquid epoxy resin content may be 5 to 20% by mass, based on the total amount of the adhesive film.

Another aspect of this disclosure relates to a dicing-die bonding integrated film. This dicing-die bonding integrated film comprises a dicing film and the aforementioned adhesive film provided on the dicing film.

Other aspects of this disclosure relate to methods for manufacturing semiconductor devices. One embodiment of a method for manufacturing a semiconductor device includes bonding a second semiconductor chip to a substrate on which a first semiconductor chip is mounted using the adhesive film described above. In this case, the first semiconductor chip is embedded by the adhesive film.

Another embodiment of the method for manufacturing a semiconductor device includes bonding a second semiconductor chip to a first semiconductor chip using the adhesive film described above. In this case, part or all of the wires are embedded by the adhesive film.

In one or another embodiment of the semiconductor device manufacturing method, the first semiconductor chip may be a controller chip.

This disclosure provides a semiconductor adhesive film that can suppress bleeding when embedding semiconductor chips or wires and has sufficient fracture strength after curing. Furthermore, this disclosure provides a dicing/die bonding integrated film incorporating such a semiconductor adhesive film. Moreover, this disclosure provides a method for manufacturing a semiconductor device using these semiconductor adhesive films or dicing/die bonding integrated films.

Figure 1 is a schematic cross-sectional view showing one embodiment of an adhesive film. Figure 2 is a schematic cross-sectional view showing one embodiment of a laminate comprising an adhesive film. Figure 3 is a schematic cross-sectional view showing one embodiment of a laminate comprising an adhesive film. Figure 4 is a schematic cross-sectional view showing one embodiment of a semiconductor device. Figure 5 is a process diagram showing one embodiment of a method for manufacturing a semiconductor device. Figure 6 is a process diagram showing one embodiment of a method for manufacturing a semiconductor device. Figure 7 is a process diagram showing one embodiment of a method for manufacturing a semiconductor device. Figure 8 is a process diagram showing one embodiment of a method for manufacturing a semiconductor device. Figure 9 is a process diagram showing one embodiment of a method for manufacturing a semiconductor device. Figure 10 is a schematic cross-sectional view showing another embodiment of the semiconductor device. Figure 11 is a schematic cross-sectional view showing another embodiment of the semiconductor device.

This disclosure is not limited to the following examples. In the following examples, the components (including steps, etc.) are not essential unless otherwise explicitly stated. The sizes of the components in each figure are conceptual, and the relative sizes of the components are not limited to those shown in each figure. The numerical values and their ranges exemplified below are not limiting to this disclosure.

In this specification, numerical ranges indicated using "~" represent a range that includes the numbers before and after "~" as the minimum and maximum values, respectively. In numerical ranges described in stages within this specification, the upper or lower limit of one numerical range may be replaced by the upper or lower limit of another numerical range described in stages. In numerical ranges described within this specification, the upper or lower limit of that range may be replaced by the values shown in the examples.

In this specification, (meth)acrylate means acrylate or the corresponding methacrylate. The same applies to other similar expressions such as (meth)acrylic acid ester, (meth)acryloyl group, and (meth)acrylic copolymer.

The materials exemplified below may be used individually or in combination of two or more, unless otherwise specified. The content of each component in the composition refers to the total amount of any multiple substances present in the composition, unless otherwise specified.

[Semiconductor adhesive film (adhesive film)]
Figure 1 is a schematic cross-sectional view showing one embodiment of an adhesive film. The adhesive film 10 shown in Figure 1 contains a thermosetting component (hereinafter sometimes referred to as "component (A)"), an elastomer (hereinafter sometimes referred to as "component (B)"), a first inorganic filler (hereinafter sometimes referred to as "component (C1)"), and a second inorganic filler (hereinafter sometimes referred to as "component (C2)"). In addition to components (A), (B), (C1), and (C2), the adhesive film 10 may also contain a curing accelerator (hereinafter sometimes referred to as "component (D)"), a coupling agent (hereinafter sometimes referred to as "component (E)"), and other components. The adhesive film 10 may be a film formed from a thermosetting adhesive containing components (A), (B), (C1), (C2), etc. The adhesive film 10 may be in a semi-cured (B stage) state. The adhesive film 10 may become cured (C stage) after curing treatment.

(A) Component: Thermosetting component Component (A) may include (A1) a thermosetting resin which is a compound having a functional group that forms a crosslinked structure by a thermosetting reaction, and may further include (A2) a curing agent which reacts with the thermosetting resin. From the viewpoint of adhesion, the thermosetting resin may include an epoxy resin which is a compound having an epoxy group. In that case, the curing agent may include a phenolic resin which is a compound having a phenolic hydroxyl group.

Examples of epoxy resins used as thermosetting resins 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, stilbene type epoxy resin, triazine skeleton-containing epoxy resin, fluorene skeleton-containing epoxy resin, triphenolmethane type epoxy resin, biphenyl type epoxy resin, xylylene type epoxy resin, biphenyl aralkyl type epoxy resin, naphthalene type epoxy resin, and diglycidyl ether compounds of polycyclic aromatics such as polyfunctional phenols and anthracenes. These may be used individually or in combination of two or more. Among these, the epoxy resin may include cresol novolac type epoxy resin, bisphenol F type epoxy resin, bisphenol A type epoxy resin, or a combination thereof, from the viewpoint of film tackiness, flexibility, etc.

The epoxy resin may contain a liquid epoxy resin that is liquid at 30°C (an epoxy resin with a softening point of 40°C or lower). That is, the epoxy resin may be a combination of a liquid epoxy resin and a solid epoxy resin that is solid at 30°C (an epoxy resin with a softening point exceeding 40°C). In this specification, the softening point refers to the value measured by the ring-and-ball method in accordance with JIS K7234. The liquid epoxy resin content may be 3 to 20% by mass, based on the total amount of adhesive film. The inclusion of a liquid epoxy resin in the thermosetting resin tends to improve the flexibility of the adhesive film. Furthermore, combining a liquid epoxy resin with a solid epoxy resin tends to improve the embedding properties of semiconductor chips and wires.

Examples of commercially available liquid epoxy resins include EXA-830CRP (product name, manufactured by DIC Corporation, liquid at 30°C), YDF-8170C (product name, manufactured by Nippon Steel Chemical & Material Co., Ltd., liquid at 30°C), and EP-4088S (product name, manufactured by ADEKA Corporation, liquid at 30°C).

The epoxy equivalent of the epoxy resin is not particularly limited, but may be 90-300 g/eq or 110-290 g/eq. When the epoxy equivalent of the epoxy resin is within this range, it tends to be easier to maintain the bulk strength of the adhesive film while ensuring the fluidity of the thermosetting adhesive when forming the adhesive film.

Examples of phenolic resins used as curing agents include novolac-type phenolic resins obtained by condensing or co-condensing phenols such as phenol, cresol, resorcinol, catechol, bisphenol A, bisphenol F, phenylphenol, and aminophenol, and/or naphthols such as α-naphthol, β-naphthol, and dihydroxynaphthalene with compounds having an aldehyde group such as formaldehyde under an acidic catalyst; phenolic aralkyl resins and naphthol aralkyl resins synthesized from phenols such as allylated bisphenol A, allylated bisphenol F, allylated naphthalenediol, phenol novolac, and phenol, and/or naphthols with dimethoxyp-xylene or bis(methoxymethyl)biphenyl. These may be used individually or in combination of two or more. The phenolic resin may contain phenylaralkyl-type phenolic resins, phenolic novolac resins, or combinations thereof.

The hydroxyl group equivalent of the phenolic resin may be 70 g/eq or more, or 70 to 300 g/eq. When the hydroxyl group equivalent of the phenolic resin is 70 g/eq or more, the storage modulus of the adhesive film tends to increase further. When the hydroxyl group equivalent of the phenolic resin is 300 g/eq or less, foaming and outgassing can be further suppressed.

Examples of commercially available phenolic resins include PSM-4326 (trade name, manufactured by Gun-ei Chemical Industry Co., Ltd., softening point: 120°C), J-DPP-140 (trade name, manufactured by JFE Chemical Corporation, softening point: 140°C), GPH-103 (trade name, manufactured by Nippon Kayaku Co., Ltd., softening point: 99-106°C), MEH-7800M (trade name, manufactured by Meiwa Kasei Co., Ltd., softening point: 80°C), J-DPP-85 (trade name, manufactured by JFE Chemical Corporation, softening point: 85°C), and MEH-5100-5S (trade name, manufactured by Meiwa Kasei Co., Ltd., softening point: 65°C).

When a thermosetting resin contains epoxy resin and a curing agent contains phenolic resin, the ratio of epoxy equivalents of the epoxy resin to the hydroxyl group equivalents of the phenolic resin (epoxy equivalents:hydroxyl group equivalents) may be 0.30/0.70 to 0.70/0.30, 0.35/0.65 to 0.65/0.35, 0.40/0.60 to 0.60/0.40, or 0.45/0.55 to 0.55/0.45, from the viewpoint of curability. A ratio of 0.30/0.70 or higher tends to yield more sufficient curability. A ratio of 0.70/0.30 or lower prevents excessive viscosity and allows for more sufficient fluidity.

The softening point of the curing agent may be 50–200°C or 60–150°C. Curing agents with a softening point of 200°C or lower tend to have good compatibility with thermosetting resins.

The content of component (A) (total content of thermosetting resin and curing agent) may be 10 to 40% by mass, based on the total amount of adhesive film. When the content of component (A) is 10% by mass or more, based on the total amount of adhesive film, the tensile strength of the adhesive film after curing tends to improve, and when it is 40% by mass or less, bleeding when embedding semiconductor chips or wires tends to be suppressed more effectively. The content of component (A) (total content of thermosetting resin and curing agent) may be 15% by mass or more, 20% by mass or more, or 25% by mass or more, and may be 38% by mass or less, 35% by mass or less, or 32% by mass or less, based on the total amount of adhesive film.

(B) Component: Elastomer Examples of component (B) include acrylic resin, polyester resin, polyamide resin, polyimide resin, silicone resin, butadiene resin; modified versions of these resins, etc. These may be used individually or in combination of two or more. Among these, component (B) may be an acrylic resin (acrylic rubber) having constituent units derived from (meth)acrylic acid ester as its main component, as it has fewer ionic impurities and superior heat resistance, makes it easier to ensure connection reliability of semiconductor devices, and has superior fluidity. The content of constituent units derived from (meth)acrylic acid ester in component (B) may be, for example, 70% by mass or more, 80% by mass or more, or 90% by mass or more, based on the total amount of constituent units. The acrylic resin (acrylic rubber) may also contain constituent units derived from (meth)acrylic acid ester having crosslinkable functional groups such as epoxy groups, alcoholic or phenolic hydroxyl groups, or carboxyl groups.

The glass transition temperature (Tg) of component (B) may be -50 to 50°C or -30 to 30°C. When the Tg of component (B) is -50°C or higher, it tends to prevent the adhesive film from becoming too flexible. This makes it easier to cut the adhesive film during wafer dicing and prevents the generation of burrs. When the Tg of component (B) is 50°C or lower, it tends to suppress the decrease in the flexibility of the adhesive film. This tends to make it easier to adequately fill voids when attaching the adhesive film to the semiconductor wafer. It also prevents chipping during dicing due to reduced adhesion of the semiconductor wafer. Here, the glass transition temperature (Tg) refers to the value measured using a DSC (Differential Scanning Calorimeter) (for example, Rigaku Corporation's "Thermo Plus 2"). The Tg of component (B) can be adjusted to a desired range by adjusting the type and content of the constituent units that make up component (B) (in the case of component (B) being acrylic resin (acrylic rubber), the constituent units derived from (meth)acrylic acid ester).

The weight-average molecular weight (Mw) of component (B) may be between 100,000 and 3,000,000 or between 200,000 and 1,000,000. When the Mw of component (B) is within this range, film formation properties, film strength, flexibility, tackiness, etc., can be appropriately controlled, and excellent reflowability and improved embedding properties can be achieved. Here, Mw refers to the value measured by gel permeation chromatography (GPC) and converted using a calibration curve with standard polystyrene. If multiple peaks are observed in GPC, the weight-average molecular weight attributable to the peak with the highest peak intensity is defined as the weight-average molecular weight in this specification.

Examples of commercially available components (B) include SG-70L, SG-708-6, WS-023 EK30, SG-P3, SG-280 EK23, SG-80H, HTR-860P, HTR-860P-3, HTR-860P-3CSP, HTR-860P-3CSP-3DB, and HTR-860P-30B (all manufactured by Nagase ChemteX Corporation).

The content of component (B) may be 15 to 35% by mass based on the total amount of adhesive film. When the content of component (B) is 15% by mass or more based on the total amount of adhesive film, the embedding properties tend to improve, and when it is 40% by mass or less, the adhesive strength of the adhesive film tends to improve. The content of component (B) may be 18% by mass or more, 20% by mass or more, 32% by mass or less, 30% by mass or less, or 28% by mass or less based on the total amount of adhesive film.

(C1) Component: First inorganic filler (C2) Component: Second inorganic filler The adhesive film contains components (C1) and (C2). Components (C1) and (C2) satisfy all of the following conditions. By containing components (C1) and (C2), it is possible to suppress bleeding when embedding semiconductor chips or wires, and furthermore, it is possible to improve the fracture strength after curing.
The average particle size of component (C1) is 300 to 1000 nm.
The average particle size of component (C2) is 0.05 to 0.70 times that of component (C1).
The total content of components (C1) and (C2) is 30 to 60% by mass, based on the total amount of adhesive film.

Component (C1) and component (C2) may be at least one selected from, for example, 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 silica. From the viewpoint of adjusting the melt viscosity, component (C1) and component (C2) may also contain silica.

The average particle size of component (C1) is 300 to 1000 nm, and may be 350 nm or more, 400 nm or more, or 450 nm or more, and may be 900 nm or less, 800 nm or less, 700 nm or less, or 600 nm or less.

The average particle size of component (C2) may be less than 300 nm, and may be 250 nm or less, 220 nm or less, or 200 nm or less. For example, the average particle size of component (C2) may be 10 nm or more, 50 nm or more, or 100 nm or more.

In this specification, these average particle sizes refer to the particle size with a cumulative frequency of 50% in the particle size distribution determined by laser diffraction/scattering. The average particle sizes of components (C1) and (C2) can also be determined by using an adhesive film containing components (C1) and (C2). In this case, a dispersion is prepared by dispersing the residue obtained by heating the adhesive film to decompose the resin components in a solvent. From the particle size distribution obtained by applying laser diffraction/scattering to this dispersion, the value of the peak in the range of 300 to 1000 nm can be used as the average particle size of component (C1), and the value of the peak in the range of less than 300 nm can be used as the average particle size of component (C2).

The average particle size of component (C2) is 0.05 to 0.70 times that of component (C1). The average particle size of component (C2) may be 0.10 times or more, 0.20 times or more, or 0.30 times or more, and may also be 0.60 times or less, 0.50 times or less, or 0.40 times or less.

The content of component (C1) may be 5 to 40% by mass, based on the total amount of adhesive film, and may be 6% or more by mass, 8% or more by mass, or 10% or more by mass, and may be 35% or less by mass, 32% or less by mass, or 30% or less by mass.

The content of component (C2) may be 10 to 50% by mass, based on the total amount of adhesive film, and may be 15% or more by mass, 18% or more by mass, or 20% or more by mass, and may be 45% or less by mass, 42% or less by mass, or 40% or less by mass.

The total content of components (C1) and (C2) is 30 to 60% by mass, based on the total amount of adhesive film, and may be 35% or more by mass, 40% or more by mass, or 45% or more by mass, and may be 55% or less by mass, 52% or less by mass, or 50% or less by mass.

The mass ratio of component (C1) to the total of components (C1) and (C2) may be 10 to 70% by mass, and may be 15% or more by mass, 18% or more by mass, or 20% or more by mass, and may be 65% or less by mass, 62% or less by mass, or 60% or less by mass.

The mass ratio of component (C2) to the total of component (C1) and component (C2) may be 30 to 90% by mass, and may be 35% or more by mass, 38% or more by mass, or 40% or more by mass, and may be 85% or less by mass, 82% or less by mass, or 80% or less by mass.

(D) Component: Curing accelerator Examples of component (D) include imidazoles and their derivatives, organophosphorus compounds, secondary amines, tertiary amines, quaternary ammonium salts, etc. These may be used individually or in combination of two or more. Among these, from the viewpoint of reactivity, component (D) may be imidazoles and their derivatives.

Examples of imidazoles include 2-methylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, and 1-cyanoethyl-2-methylimidazole. These may be used individually or in combination of two or more.

(E) Component: Coupling agent Component (E) may be a silane coupling agent. Examples of silane coupling agents include γ-ureidopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, 3-phenylaminopropyltrimethoxysilane, and 3-(2-aminoethyl)aminopropyltrimethoxysilane. These may be used individually or in combination of two or more.

The adhesive film may further contain other components. Examples of other components include pigments, ion capture agents, and antioxidants.

The total content of component (D), component (E), and other components may be 0.1% by mass or more, 0.3% by mass or more, or 0.5% by mass or more, based on the total amount of adhesive film, and may be 30% by mass or less, 20% by mass or less, 10% by mass or less, or 5% by mass or less.

The adhesive film 10 can be formed, for example, by applying a thermosetting adhesive to a support film. In forming the adhesive film 10, a thermosetting adhesive varnish (adhesive varnish) may also be used. When using an adhesive varnish, the adhesive varnish is prepared by mixing or kneading components (A), (B), (C1), and (C2), along with any additional components as needed, in a solvent. The resulting adhesive varnish is then applied to the support film, and the solvent is removed by heating and drying to obtain the adhesive film 10.

The support film is not particularly limited as long as it can withstand the above-mentioned heat drying, but may be, for example, polyester film, polypropylene film, polyethylene terephthalate film, polyimide film, polyetherimide film, polyethylene naphthalate film, polymethylpentene film, etc. The support film may be a multilayer film combining two or more types, and its surface may be treated with a release agent such as silicone or silica. The thickness of the support film may be, for example, 10 to 200 μm or 20 to 170 μm.

Mixing or kneading can be performed using conventional agitators, dispersers, three-roll mills, ball mills, and other dispersing machines, in appropriate combinations.

The solvent used in the preparation of the adhesive varnish is not limited as long as it can uniformly dissolve, knead, or disperse each component; conventionally known solvents can be used. Examples of such solvents include ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, as well as dimethylformamide, dimethylacetamide, N-methylpyrrolidone, toluene, and xylene. From the viewpoint of drying speed and cost, the solvent may be methyl ethyl ketone or cyclohexanone.

As for the method of applying the adhesive varnish to the support film, known methods can be used, such as the knife coating method, roll coating method, spray coating method, gravure coating method, bar coating method, curtain coating method, etc. The heating and drying conditions are not particularly limited as long as the conditions allow the solvent used to evaporate sufficiently, but for example, 50 to 150°C for 1 to 30 minutes may be used.

The thickness of the adhesive film 10 may be, for example, 1 μm or more, 3 μm or more, 20 μm or more, 25 μm or more, 30 μm or more, 35 μm or more, 40 μm or more, 50 μm or more, 60 μm or more, 70 μm or more, or 80 μm or more, and may be 200 μm or less, 150 μm or less, 120 μm or less, 100 μm or less, 80 μm or less, or 60 μm or less. If the adhesive film 10 is an adhesive film for FOD, the thickness of the adhesive film 10 may be, for example, 40 to 200 μm, 60 to 150 μm, or 80 to 120 μm in order to properly embed the entire semiconductor chip (e.g., controller chip). If the adhesive film 10 is an adhesive film for FOW (Fixed-On Wire), the thickness of the adhesive film 10 may be, for example, 20 to 120 μm, 25 to 80 μm, or 30 to 60 μm, in order to embed the wires so that they do not come into contact with the semiconductor chip.

According to the inventors' findings, the shear viscosity of the adhesive film 10 in the range of 60 to 150°C, particularly at a frequency of 4.4 Hz, is related to the degree of bleeding of the adhesive film 10. When the shear viscosity of the adhesive film 10 at a frequency of 4.4 Hz is at least 3000 Pa·s and at most 200,000 Pa·s in the range of 60 to 150°C, the embedding properties in FOD or FOW tend to improve while suppressing bleeding.

At temperatures between 60 and 150°C, the minimum shear viscosity of the adhesive film 10 at a frequency of 4.4 Hz may be 3200 Pa·s or higher, or 3500 Pa·s or higher, from the viewpoint of suppressing bleeding and other factors.

At temperatures between 60 and 150°C, the maximum shear viscosity of the adhesive film 10 at a frequency of 4.4 Hz may be 180,000 Pa·s or less, 175,000 Pa·s or less, 170,000 Pa·s or less, or 165,000 Pa·s or less, from the viewpoint of further improving embedding properties.

The adhesive film 10, fabricated on the support film, may have a cover film on the side opposite to the support film to prevent damage or contamination. Examples of the cover film include polyethylene film, polypropylene film, and surface-release agent treated film. The thickness of the cover film may be, for example, 15 to 200 μm or 30 to 170 μm.

The adhesive film 10 can be used, for example, as a protective sheet to protect the back surface of a semiconductor element (semiconductor chip) in a flip-chip semiconductor device, or as a sealing sheet to seal the space between the surface of a semiconductor element (semiconductor chip) in a flip-chip semiconductor device and the adherend.

[Dicing and die bonding integrated film]
Figures 2 and 3 are schematic cross-sectional views showing one embodiment of a laminate comprising an adhesive film. The adhesive film 10 may be supplied in the form of the laminate shown in Figure 2 or Figure 3. The laminate 100 shown in Figure 2 comprises a base layer 20 and an adhesive film 10 provided on the base layer 20. The laminate 110 shown in Figure 3 further comprises a protective film 30 provided on the surface of the adhesive film 10 opposite to the base layer 20 relative to the laminate 100.

The base layer 20 may be a resin film similar to the support film. The thickness of the base layer 20 may be, for example, 10 to 200 μm or 20 to 170 μm.

The base layer 20 may be a dicing film. A laminate in which the base layer 20 is a dicing film can be used as a dicing-die bonding integrated film. The dicing-die bonding integrated film may be in the form of a film, sheet, or tape.

Examples of dicing films include resin films such as polytetrafluoroethylene film, polyethylene terephthalate film, polyethylene film, polypropylene film, polymethylpentene film, and polyimide film. The dicing film may be a resin film surface-treated as needed by primer application, UV treatment, corona discharge treatment, polishing, or etching. The dicing film may also be adhesive. An adhesive dicing film may be, for example, a resin film to which adhesiveness has been imparted, or a laminated film having a resin film and an adhesive layer provided on one side thereof. The adhesive layer can be formed from a pressure-sensitive or UV-curable adhesive. A pressure-sensitive adhesive is an adhesive that exhibits a certain level of tackiness with short-term pressure. A UV-curable adhesive is an adhesive whose tackiness decreases upon irradiation with ultraviolet light. The thickness of the adhesive layer can be appropriately set according to the shape and dimensions of the semiconductor device, but may be, for example, 1 to 100 μm, 5 to 70 μm, or 10 to 40 μm. The thickness of the substrate layer 20, which is the dicing film, may be 60 to 150 μm or 70 to 130 μm, from the viewpoint of economy and ease of handling the film.

The protective film 30 may be a resin film similar to the cover film. The thickness of the protective film 30 may be, for example, 15 to 200 μm or 30 to 170 μm.

[Semiconductor device and method for manufacturing the same]
Figure 4 is a schematic cross-sectional view showing one embodiment of a semiconductor device, illustrating an example of a semiconductor device manufactured using an adhesive film. The semiconductor device 200 shown in Figure 4 mainly consists of a substrate 14, a first semiconductor chip Wa and a second semiconductor chip Waa mounted on the substrate 14, a sealing layer 42 that seals the second semiconductor chip Waa, and an adhesive film 10 that adheres the second semiconductor chip Waa to the substrate 14. The substrate 14 has an organic substrate 90 and circuit patterns 84, 94 provided on the organic substrate 90. The first semiconductor chip Wa is bonded to the substrate 14 by an adhesive 41. A first wire 88 is connected to the first semiconductor chip Wa, and the first semiconductor chip Wa is electrically connected to the circuit pattern 84 via the first wire 88. The entire first semiconductor chip Wa and the entire first wire 88 are embedded in the adhesive film 10. A second wire 98 is connected to a second semiconductor chip Waa, and the second semiconductor chip Waa is electrically connected to the circuit pattern 84 via the second wire 98. The entire second semiconductor chip Waa and the entire second wire 98 are embedded in the sealing layer 42.

Figures 5, 6, 7, 8, and 9 are process diagrams illustrating one embodiment of a semiconductor device manufacturing method, and show an example of a manufacturing method for the semiconductor device 200 shown in Figure 4. The method shown in Figures 5-9 includes: adhering a first semiconductor chip Wa to a substrate 14 via an adhesive 41; providing a first wire 88 connecting the first semiconductor chip Wa to the substrate 14 (circuit pattern 84); preparing an adhesive-coated chip having a second semiconductor chip Wbb and an adhesive film 10 attached thereto; pressing the adhesive-coated chip to the substrate 14, thereby adhering the second semiconductor chip Waa to the substrate 14 such that the first semiconductor chip Wa and the first wire 88 are embedded by the adhesive film 10; and providing a second wire 98 connecting the second semiconductor chip Waa to the substrate 14 (circuit pattern 84). Subsequently, by forming a sealing layer 44, the semiconductor device 200 shown in Figure 4 can be obtained.

The thickness of the first semiconductor chip Wa may be 10 to 170 μm. The first semiconductor chip Wa may be a controller chip for driving the semiconductor device 200. The first semiconductor chip Wa may be a flip-chip type chip. The size of the first semiconductor chip Wa is usually smaller than the size of the second semiconductor chip Waa. The adhesive 41 interposed between the first semiconductor chip Wa and the substrate 14 may be a known semiconductor adhesive used in the relevant field.

As shown in Figure 5, the substrate 14 (circuit pattern 84) and the first semiconductor chip Wa are electrically connected via the first wire 88. The first wire 88 connecting the first semiconductor chip Wa and the substrate 14 (circuit pattern 84) may be, for example, a gold wire, an aluminum wire, or a copper wire. The heating temperature for connecting the first wire 88 may be in the range of 80 to 250°C or 80 to 220°C. The heating time for connecting the first wire 88 may be several seconds to several minutes. For connecting the first wire 88, vibration energy from ultrasound and crimping energy from applied pressure may be applied.

The adhesive-bonded chip, consisting of a second semiconductor chip Waa and an adhesive film 10, can be prepared, for example, using a dicing-die bonding integrated film having a similar configuration to the laminate 100 shown in Figure 2. In this case, for example, the laminate 100 (dicing-die bonding integrated film) is attached to one side of a semiconductor wafer, with the adhesive film 10 facing the semiconductor wafer. The surface to which the adhesive film 10 is attached may be the circuit side of the semiconductor wafer or the opposite back side. By dicing the semiconductor wafer to which the laminate 100 (dicing-die bonding integrated film) is attached, individual second semiconductor chips Waa are formed. Examples of dicing include blade dicing using a rotating blade, and stealth dicing, which creates a modified region on the semiconductor wafer using a laser and expands the substrate layer. The second semiconductor chip Waa is picked up together with the divided adhesive film 10. If the adhesive layer of the dicing film is made of an ultraviolet-curing adhesive, the adhesive strength of the adhesive layer may be reduced by irradiating it with ultraviolet light before picking up the second semiconductor chip Waa, if necessary.

The second semiconductor chip Waa may have a width of 20 mm or less. The width (or the length of one side) of the second semiconductor chip Waa may be 3 to 15 mm or 5 to 10 mm.

The semiconductor wafer used to form the second semiconductor chip Waa may be, for example, a thin semiconductor wafer having a thickness of 10 to 100 μm. The semiconductor wafer may be made of single-crystal silicon, polycrystalline silicon, various ceramics, or compound semiconductors such as gallium arsenide. The second semiconductor chip Waa may also be formed from a similar semiconductor wafer.

As shown in Figure 7, an adhesive-backed chip consisting of an adhesive film 10 and a second semiconductor chip Waa is placed such that the first wire 88 and the first semiconductor chip Waa are covered by the adhesive film 10. Next, as shown in Figure 8, the second semiconductor chip Waa is fixed to the substrate 14 by pressing it against the substrate 14. The heating temperature for pressing may be 50 to 200°C or 100 to 150°C. A higher heating temperature for pressing tends to improve embedding performance because the adhesive film 10 becomes softer. The pressing time may be 0.5 to 20 seconds or 1 to 5 seconds. The pressure for pressing may be 0.01 to 5 MPa or 0.02 to 2 MPa.

After pressing, the structure containing the adhesive film 10 may be further heated to cure the adhesive film 10. The temperature and time for curing can be appropriately set depending on the curing temperature of the adhesive film 10, etc. The temperature may be changed in stages. The heating temperature may be, for example, 40 to 300°C or 60 to 200°C. The heating time may be, for example, 30 to 300 minutes.

As shown in Figure 9, the substrate 14 and the second semiconductor chip Waa are electrically connected via the second wire 98. The type and connection method of the second wire 98 may be the same as those of the first wire 88.

Subsequently, a sealing layer 42 is formed using a sealing material to enclose the circuit pattern 84, the second wire 98, and the second semiconductor chip Waa. The sealing layer 42 can be formed, for example, by a conventional method using a mold. After the sealing layer 42 is formed, the adhesive film 10 and the sealing layer 42 may be further heat-cured by heating. The heating temperature for this purpose may be, for example, 165 to 185°C, and the heating time may be approximately 0.5 to 8 hours.

Figure 10 is a schematic cross-sectional view showing another embodiment of the semiconductor device. The semiconductor device 201 mainly consists of a substrate 14, a first semiconductor chip Wa and a second semiconductor chip Waa mounted on the substrate 14, a sealing layer 42 that seals the first semiconductor chip Wa and the second semiconductor chip Waa, and an adhesive film 10 that adheres the second semiconductor chip Waa to the first semiconductor chip Wa. The substrate 14 has an organic substrate 90, circuit patterns 84 and 94 provided on the organic substrate 90, and connection terminals 95 provided on the surface of the organic substrate 90 opposite to the circuit patterns 84 and 94. The first semiconductor chip Wa is bonded to the substrate 14 by adhesive 41. A first wire 88 is connected to the first semiconductor chip Wa, and the first semiconductor chip Wa is electrically connected to the circuit pattern 84 via the first wire 88. A part of the first wire 88 is embedded in the adhesive film 10. The second semiconductor chip Waa is connected to the second wire 98, and the second semiconductor chip Waa is electrically connected to the circuit pattern 84 via the second wire 98.

The semiconductor device 201 shown in Figure 10 can be manufactured by the same method as the manufacturing method of the semiconductor device 200, which includes bonding a second semiconductor chip Waa to a first semiconductor chip Wa using an adhesive film 10.

Figure 11 is a schematic cross-sectional view showing another embodiment of the semiconductor device. The semiconductor device 202 mainly consists of a substrate 14 (organic substrate 90), a first semiconductor chip Wa and a second semiconductor chip Waa mounted on the substrate 14, a sealing layer 42 that encapsulates the first semiconductor chip Wa and the second semiconductor chip Waa, and an adhesive film 10 that adheres the second semiconductor chip Waa to the substrate 14 while embedding the entire first semiconductor chip Wa. The first semiconductor chip Wa is a flip-chip type chip and is electrically connected to the substrate 14 via a plurality of electrodes 96. An underfill 50 is filled between the first semiconductor chip Wa and the substrate 14.

The present disclosure will be described below in detail based on examples, but the disclosure is not limited to these examples.

[Preparation of adhesive film]
(Examples 1-3 and Comparative Examples 1-5)
<Preparation of adhesive varnish>
Cyclohexanone was added to compositions consisting of components (A), (C1), and (C2) as shown in Table 1, and stirred and mixed. Component (B) shown in Table 1 was then added and stirred, and components (D) and (E) shown in Table 1 were further added and stirred until all components were homogeneous to prepare the adhesive varnishes of Examples 1-3 and Comparative Examples 1-5. The numerical values for components (B), (C1), and (C2) shown in Table 1 represent parts by mass of solids.

(A) Component: Thermosetting resin component (A1) Component: Thermosetting resin (A1-1) N-500P-10 (Trade name, manufactured by DIC Corporation, o-cresol novolac type epoxy resin, epoxy equivalent: 204 g/eq, softening point: 75-85°C)
(A1-2) EXA-830CRP (product name, manufactured by DIC Corporation, liquid bisphenol F type epoxy resin, epoxy equivalent: 159 g/eq)

(A2) Ingredients: Hardener (A2-1) MEH-7800M (product name, manufactured by Meiwa Chemical Co., Ltd., phenyl aralkyl type phenolic resin, hydroxyl group equivalent: 174 g/eq, softening point: 80°C)
(A2-2) PSM-4326 (product name, manufactured by Gun-ei Chemical Co., Ltd., phenol novolac resin, hydroxyl group equivalent: 105 g/eq, softening point: 120°C)

(B) Component: Elastomer (B-1) Acrylic resin A (HTR-860P-3CSP (product name), manufactured by Nagase ChemteX Corporation, acrylic resin, weight-average molecular weight: 800,000, Tg: 12℃)
(B-2) Acrylic resin B (acrylic resin that is a copolymer of butyl acrylate/ethyl acrylate/ethyl methacrylate/glycidyl methacrylate/styrene, weight-average molecular weight: 400,000, Tg: 5℃)

(C1) Component: Primary inorganic filler (C1-1) Silica filler A (SC2050-HLG (product name), manufactured by Admatex Co., Ltd., silica filler dispersion, average particle size: 500 nm)
(C2) Component: Second inorganic filler (C2-1) Silica filler B (silica filler dispersion, average particle size: 180 nm)

(D) Curing accelerator (D-1) 2PZ-CN (trade name, manufactured by Shikoku Chemicals Co., Ltd., 1-cyanoethyl-2-phenylimidazole)

(E) Ingredient: Coupling agent (E-1) A-189 (product name, manufactured by Nippon Unicar Co., Ltd., γ-mercaptopropyltrimethoxysilane)
(E-2) A-1160 (product name, manufactured by Nippon Unicar Co., Ltd., γ-ureidopropyltriethoxysilane)

<Preparation of adhesive film>
The prepared adhesive varnish was filtered through a 100-mesh filter and degassed under vacuum. A 38 μm thick polyethylene terephthalate (PET) film with a release treatment was prepared as the base layer, and the degassed adhesive varnish was applied to the PET film. The applied adhesive varnish was heated and dried in two stages: 90°C for 5 minutes, followed by 140°C for 5 minutes, to obtain the adhesive films of Examples 1-3 and Comparative Examples 1, 2, and 5, which were in the B-stage state. In the case of Comparative Examples 3 and 4, the film formation properties were insufficient, and adhesive films could not be obtained. In the adhesive films of Examples 1-3 and Comparative Examples 1, 2, and 5, the thickness was adjusted to 60 μm by controlling the amount of adhesive varnish applied. Two of the obtained 60 μm thick adhesive films were prepared and bonded together at 70°C to produce an adhesive film with a thickness of 120 μm.

[Evaluation of adhesive films]
<Measurement of shear viscosity>
Shear viscosity was measured using the following method. Specifically, multiple layers of adhesive films from Examples 1-3 and Comparative Examples 1, 2, and 5 were stacked to a thickness of approximately 1000 μm, and a sample for measurement was obtained by punching it out into a circle with a diameter of 9 mm. A circular aluminum plate jig with a diameter of 8 mm was set in a dynamic viscoelastic device ARES (trade name, manufactured by TA Instruments), and the sample was then placed on the jig. Subsequently, the shear viscosity was measured under the following measurement conditions, and the minimum value of shear viscosity within the range of 60 to 150°C was read from the measurement results. The results are shown in Table 1. The larger the minimum value of shear viscosity (for example, 3000 Pa·s or more), the more likely it is that bleeding when embedding semiconductor chips or wires can be suppressed.
(Measurement conditions)
・Measurement temperature: 35-160℃
• Heating rate: 5°C/min • Strain: 5%
Frequency: 4.4 Hz
・Initial load: 10g

<Evaluation of implantability>
(Fabrication of semiconductor chips with adhesive film)
A semiconductor wafer (40 μm thick) was attached to the adhesive film side of a dicing/die bonding integrated film HR-5104-10 (manufactured by Showa Denko Materials Co., Ltd., adhesive film thickness 10 μm, adhesive layer thickness 110 μm) at a stage temperature of 70°C. Dicing was performed using a fully automatic dicer DFD-6361 (manufactured by Disco Corporation) to form a semiconductor chip (controller chip) with a size of 1.6 mm x 4 mm. The semiconductor chip with adhesive film, consisting of the controller chip and the adhesive film attached thereto, was picked up to obtain the first semiconductor chip. Next, a dicing film (manufactured by Showa Denko Materials Co., Ltd., thickness 100 μm) having a resin film and an adhesive layer was prepared, and the adhesive films (thickness 120 μm) of Examples 1 to 3 and Comparative Examples 1, 2, and 5 were attached to it, respectively, to produce a dicing/die bonding integrated film comprising a dicing film and an adhesive film provided on one side of the dicing film. Next, a semiconductor wafer (90 μm thick) was attached to the adhesive film side of the dicing-die bonding integrated film at a stage temperature of 70°C. Dicing was performed using a fully automatic dicer DFD-6361 (manufactured by Disco Corporation) to form a semiconductor chip with dimensions of 6 mm x 12 mm. The semiconductor chip with adhesive film attached, consisting of the semiconductor chip and the adhesive film attached to it, was picked up to obtain a second semiconductor chip.

(Preparation of evaluation laminates)
An organic substrate was prepared for bonding a first semiconductor chip and a second semiconductor chip. The first semiconductor chip was bonded to this substrate via an adhesive film using a bonding machine (Besi die bonder, product name: Esec 2100sD PPPplus) under the conditions of 120°C, 20N, and 1.5 seconds. Next, the second semiconductor chip was bonded over the first semiconductor chip via the adhesive film to be evaluated, under the conditions of 120°C, 20N, and 1.5 seconds. At this time, the first and second semiconductor chips, which had been bonded earlier, were aligned so that their center positions coincided in a plan view. Subsequently, the adhesive film was cured by heating at a heating rate of 15°C/min at 130°C for 1 hour to obtain a laminate for evaluation.

(Observation of voids)
The obtained evaluation laminates were analyzed using an ultrasonic imaging device (SAT) (manufactured by Insight Co., Ltd., product name: IS-350) to evaluate the presence or absence of voids. If no voids were found, the laminate was evaluated as "A" for superior embedding properties, and if even a small amount of voids were found, it was evaluated as "B". The results are shown in Table 1.

<Evaluation of Breeding Volume>
The top surface of the second semiconductor chip in the above-mentioned evaluation laminate was observed using a microscope (Keyence Corporation, product name: VHX-5000). The width of the adhesive film overhang from the edge of the second semiconductor chip was measured. The measurement was performed multiple times, and the maximum overhang width was defined as the bleed amount (μm). A bleed amount of less than 100 μm was evaluated as "A" for excellent bleed suppression, and a bleed amount of 100 μm or more was evaluated as "B". The results are shown in Table 1.

<Measurement of breaking strength>
(Preparation of hardened material)
For the measurement of breaking strength, the adhesive films (120 μm thick) from Examples 1 to 3 and Comparative Examples 1, 2, and 5 were cut into strips with a width of 10 mm and a length of 60 mm, and then heated and cured at 175°C for 5 hours to obtain cured adhesive films (120 μm thick).

(Measurement of breaking strength)
The tensile strength of the cured adhesive film was measured at 125°C using a tensile testing machine (TOYO BALDWIN UTM-III-500). The tensile strength of the cured adhesive film was measured according to JIS K7161 under conditions of a chuck distance of 40 mm and a tensile speed of 300 mm/min. The results are shown in Table 1. The higher the tensile strength (for example, 12 MPa or higher), the more likely it is that defects such as crack formation can be suppressed.

As shown in Table 1, the adhesive films of Examples 1 to 3, which combined the predetermined inorganic filler, showed superior evaluation of bleed amount and superior tensile strength after curing compared to the adhesive films of Comparative Examples 1 to 5, which did not combine the predetermined inorganic filler. These results confirm that the semiconductor adhesive film of this disclosure can suppress bleed when embedding semiconductor chips or wires, and also possesses sufficient tensile strength after curing.

10…Adhesive film, 14…Substrate, 20…Base layer (dicing film), 30…Protective film, 41…Adhesive, 42…Sealing layer, 84, 94…Circuit pattern, 88…First wire, 90…Organic substrate, 98…Second wire, 100, 110…Laminate, 200…Semiconductor device, Wa…First semiconductor chip, Waa…Second semiconductor chip.

Claims (9)

A semiconductor adhesive film comprising a thermosetting component, an elastomer, a first inorganic filler, and a second inorganic filler,
The average particle size of the first inorganic filler is 450 to 600 nm.
The average particle size of the second inorganic filler is 0.20 to 0.50 times that of the average particle size of the first inorganic filler.
The total content of the first inorganic filler and the second inorganic filler is 40 to 52 % by mass, based on the total amount of semiconductor adhesive film.
Adhesive film for semiconductors. Having a thickness of 60 to 150 μm,
The semiconductor adhesive film according to claim 1. A semiconductor adhesive film according to claim 1 or 2, used for bonding a semiconductor chip to a substrate while embedding other semiconductor chips. Having a thickness of 25 to 80 μm,
The semiconductor adhesive film according to claim 1. Used to bond a semiconductor chip to another semiconductor chip while embedding part or all of the wires connected to that semiconductor chip,
The semiconductor adhesive film according to claim 1 or 4. Dicing film and
A semiconductor adhesive film according to any one of claims 1 to 5 provided on the dicing film,
Equipped with,
Dicing and die bonding integrated film. The method includes bonding a second semiconductor chip to a substrate on which a first semiconductor chip is mounted using a semiconductor adhesive film as described in claim 1 or 2.
The first semiconductor chip is embedded by the adhesive film.
A method for manufacturing a semiconductor device. The method includes bonding a second semiconductor chip to a first semiconductor chip using a semiconductor adhesive film as described in claim 1 or 4.
A wire is connected to the first semiconductor chip.
A portion or all of the wire is embedded by the adhesive film.
A method for manufacturing a semiconductor device. The first semiconductor chip is a controller chip.
The method for manufacturing a semiconductor device according to claim 7 or 8 .