JP7656507B2 - Thermosetting resin sheets and dicing die bond films - Google Patents

Description

The present invention relates to a dicing die bond film used, for example, when manufacturing a semiconductor device, and a thermosetting resin sheet provided on the dicing die bond film.

Conventionally, dicing die bond films used in the manufacture of semiconductor devices are known. This type of dicing die bond film includes, for example, a dicing tape and a die bond sheet that is laminated to the dicing tape and adhered to a wafer. The die bond sheet is made of a thermosetting resin sheet. The dicing tape has a base layer and an adhesive layer in contact with the die bond sheet. This type of dicing die bond film is used in the manufacture of semiconductor devices, for example, as follows.

The method of manufacturing semiconductor devices generally includes a front-end process of forming a circuit surface on one side of a wafer using highly integrated electronic circuits, and a back-end process of cutting out chips from the wafer with the circuit surface formed and assembling them.

The post-processing includes, for example, a dicing process in which a weak portion is formed in the wafer for splitting the wafer into small chips (dies); a mounting process in which the surface of the wafer opposite the circuit surface is attached to a die bond sheet and the wafer is fixed to the dicing tape; an expanding process in which the wafer with the weak portion formed is split together with the die bond sheet to widen the gap between the chips; a pick-up process in which the die bond sheet is peeled off from the adhesive layer to remove the chip (die) with the die bond sheet attached; a die bond process in which the chip (die) with the die bond sheet attached is attached to an adherend via the die bond sheet; and a curing process in which the die bond sheet attached to the adherend is thermally cured. A semiconductor device is manufactured, for example, through these processes.

In the manufacturing method of the semiconductor device as described above, for example in the above pick-up process, a dicing die bond film is known that has a die bond sheet containing an epoxy resin and an adhesive layer containing a specific component to improve the removability when peeling off the die bond sheet together with the chip (for example, Patent Document 1).

More specifically, in the dicing die bond film described in Patent Document 1, the adhesive layer of the dicing tape contains a polymer composed of an acrylic acid ester as a main monomer, a hydroxyl group-containing monomer whose content relative to the acrylic acid ester is within the range of 10 to 30 mol %, and an isocyanate compound having a radical-reactive carbon-carbon double bond whose content relative to the hydroxyl group-containing monomer is within the range of 70 to 90 mol %, and the die bond film contains an epoxy resin.
According to the dicing die bond film described in Patent Document 1, the die bond film can be easily peeled off from the adhesive layer that has been hardened by ultraviolet light irradiation, and the chip can be satisfactorily picked up together with the die bond film.

JP 2009-135377 A

Incidentally, for example, in the above-mentioned die bonding process, when a chip is bonded onto an adherend via a die bond sheet, the adherend surface may have irregularities. Therefore, the die bond sheet deforms to follow the irregularities and fill in the recesses, and it is necessary to cover the surface of the adherend with the die bond sheet so as to prevent gaps from being formed.
In addition, for example, in the above curing process, the die bond sheet may warp due to the heat curing treatment, causing the chip to warp. This is thought to be due to the fact that the linear expansion coefficients of the chip, the die bond sheet (thermosetting resin sheet), and the adherend are different from each other. In particular, when the thickness of the adherend is relatively thin, the chip is likely to warp.
In order to prevent such problems, it is conceivable to design a die bond sheet so that it has good embedding properties by conforming to the irregularities of the adherend surface during die bonding, and so that warping due to heat curing treatment is reduced.

However, a thermosetting resin sheet for a die bond sheet that has good embedding properties during die bonding and suppresses warping associated with heat curing treatment, and a dicing die bond film that includes the thermosetting resin sheet (die bond sheet), have not yet been fully studied.

The present invention aims to provide a thermosetting resin sheet for die bonding that has good embedding properties during die bonding and suppresses warping associated with heat curing treatment, and a dicing die bond film that includes the thermosetting resin sheet.

In order to solve the above problems, the thermosetting resin sheet according to the present invention comprises:
In a method for manufacturing a semiconductor device, a thermosetting resin sheet is used as a die bond sheet for bonding a chip to an adherend by disposing the chip between a chip obtained by cutting a wafer having a circuit surface formed thereon and the adherend, the die bond sheet comprising:
The composition includes a crosslinkable acrylic polymer having a crosslinkable group in the molecule that undergoes a crosslinking reaction by a heat curing treatment,
The shear loss modulus G″ at 140° C. before heat curing treatment is 1 kPa or more and 20 kPa or less, and the tensile modulus at 150° C. after heat curing treatment at 150° C. for 1 hour is 0.5 MPa or more and 7.0 MPa or less.

The dicing die bond film of the present invention comprises the above-mentioned thermosetting resin sheet and a dicing tape bonded to the thermosetting resin sheet.

The thermosetting resin sheet and dicing die bond film of the present invention provide good embedding properties during die bonding and suppress warping associated with the thermosetting process.

FIG. 2 is a cross-sectional view of the dicing die bond film of the present embodiment cut in the thickness direction. 1A to 1C are cross-sectional views illustrating a stealth dicing process in a manufacturing method of a semiconductor device. 1A to 1C are cross-sectional views illustrating a stealth dicing process in a manufacturing method of a semiconductor device. 1A to 1C are cross-sectional views illustrating a stealth dicing process in a manufacturing method of a semiconductor device. 1A to 1C are cross-sectional views illustrating a back grinding process in a manufacturing method of a semiconductor device. 1A to 1C are cross-sectional views each showing a schematic view of a mounting step in a manufacturing method of a semiconductor device. 1A to 1C are cross-sectional views each showing a schematic view of a mounting step in a manufacturing method of a semiconductor device. 1A to 1C are cross-sectional views each showing a schematic view of an expanding step performed at a low temperature in a method for manufacturing a semiconductor device. 1A to 1C are cross-sectional views each showing a schematic view of an expanding step performed at a low temperature in a method for manufacturing a semiconductor device. 1A to 1C are cross-sectional views each showing a schematic view of an expanding step performed at a low temperature in a method for manufacturing a semiconductor device. 4A to 4C are cross-sectional views illustrating an expansion step at room temperature in the manufacturing method of the semiconductor device. 4A to 4C are cross-sectional views illustrating an expansion step at room temperature in the manufacturing method of the semiconductor device. 1A to 1C are cross-sectional views illustrating a pickup step in a manufacturing method of a semiconductor device. 1A to 1C are cross-sectional views each showing a schematic diagram of a die bonding step in a manufacturing method of a semiconductor device. FIG. 2 is a schematic diagram showing an example of a state of a void that may occur when a die bond sheet is bonded to an adherend. 1A to 1C are cross-sectional views each showing a schematic diagram of a wire bonding step in a manufacturing method of a semiconductor device. 5A to 5C are cross-sectional views each showing a schematic diagram of an encapsulation step in the manufacturing method of the semiconductor device. FIG. 11 is a schematic cross-sectional view showing an example of a state in which a semiconductor chip and a die bond sheet are warped.

Below, an embodiment of the thermosetting resin sheet (die bond sheet) according to the present invention and a dicing die bond film equipped with the thermosetting resin sheet (die bond sheet) will be described with reference to the drawings.

1, the dicing die bond film 1 of this embodiment includes a dicing tape 20 and a thermosetting resin sheet (die bond sheet 10) that is laminated on the adhesive layer 22 of the dicing tape 20 and adhered to a semiconductor wafer. The thermosetting resin sheet (die bond sheet 10) is to be adhered to an adherend such as a circuit board or a semiconductor chip in the manufacture of a semiconductor device.
It should be noted that the figures in the drawings are schematic diagrams and the aspect ratios are not necessarily the same as those of the actual products.

In this embodiment, the thermosetting resin sheet is used as the die bond sheet 10 of the dicing die bond film 1. Therefore, the detailed explanation of the thermosetting resin sheet will be given below based on the explanation of the die bond sheet 10.

<Dicing die bond film die bond sheet (thermosetting resin sheet)>
The die bond sheet 10 contains a crosslinkable acrylic polymer having in its molecule a crosslinkable group that undergoes a crosslinking reaction by a thermal curing treatment.
In addition, the shear loss modulus G″ of the die bond sheet 10 is 1 kPa or more and 20 kPa or less under a temperature condition of 140° C. before the heat curing treatment, and the tensile modulus of the die bond sheet 10 is 0.5 MPa or more and 7.0 MPa or less under a temperature condition of 150° C. after the heat curing treatment at 150° C. for 1 hour.

According to the die bond sheet 10 having the above configuration, the shear loss modulus G" at 140°C before the heat curing treatment is 1 kPa or more and 20 kPa or less, so that it can follow the unevenness of the adherend surface during die bonding and exhibit good embedding properties. In addition, since the tensile modulus at 150°C after one hour of heat curing treatment is 0.5 MPa or more and 7.0 MPa or less, it is possible to suppress warping of the die bond sheet 10 due to internal stress of the die bond sheet 10 caused by the heat curing treatment. In addition, since the die bond sheet 10 contains a crosslinkable acrylic polymer with a relatively low modulus of elasticity as the crosslinkable polymer, the die bond sheet 10 after curing has an appropriately low modulus of elasticity and can be flexible. Therefore, it is considered that the above internal stress of the die bond sheet 10 is alleviated, and warping of the die bond sheet 10 that may occur due to the heat curing treatment can be suppressed.

The above-mentioned crosslinkable acrylic polymer is a polymer compound in which at least a (meth)acrylic acid ester monomer is polymerized.
In this specification, the term "(meth)acrylic acid" refers to at least one of methacrylic acid and acrylic acid, and the term "(meth)acrylate" refers to at least one of methacrylate (methacrylic acid ester) and acrylate (acrylic acid ester). The same applies to the term "(meth)acrylic".

The crosslinkable acrylic polymer generally has the crosslinkable group on the side chain. The crosslinkable acrylic polymer may have the crosslinkable group at the end of the side chain. The crosslinkable acrylic polymer may have the crosslinkable group on at least one of the ends of the main chain.

The crosslinkable group contained in the molecule of the crosslinkable acrylic polymer is not particularly limited as long as it is a functional group that undergoes a crosslinking reaction by a heat curing treatment.
Examples of the crosslinkable group include a low activity crosslinkable group having active hydrogen, and a high activity crosslinkable group capable of reacting with active hydrogen.

Examples of low activity crosslinking groups include hydroxyl groups and carboxyl groups. These crosslinking groups can undergo a crosslinking reaction with epoxy groups or isocyanate groups. For example, the above-mentioned crosslinkable acrylic polymer having at least one of a hydroxyl group or a carboxyl group in the molecule can undergo a crosslinking reaction with a compound having an epoxy group or an isocyanate group in the molecule (e.g., an epoxy resin described later).

Examples of highly active crosslinkable groups include epoxy groups and isocyanate groups. These crosslinkable groups can undergo crosslinking reactions with hydroxyl groups and carboxyl groups. For example, the above-mentioned crosslinkable acrylic polymer having at least one of an epoxy group or an isocyanate group in the molecule can undergo crosslinking reactions with a compound having at least one of a hydroxyl group or a carboxyl group in the molecule (e.g., a phenolic resin, which will be described later).

The content of the constituent units of the crosslinkable group-containing monomer in the above crosslinkable acrylic polymer may be from 0.5% by mass to 50.0% by mass, or from 1% by mass to 40% by mass.
By setting the above ratio to 0.5 mass % or more, it is possible to more sufficiently advance the crosslinking reaction when the die bond sheet 10 is heat cured. On the other hand, by setting the above ratio to 50.0 mass % or less, it is possible to further reduce the elastic modulus of the die bond sheet 10 after the heat curing treatment, thereby more effectively suppressing the warping of the die bond sheet 10 caused by the heat curing treatment.
When the above-mentioned crosslinkable acrylic polymer has a hydroxy group or a carboxy group as a crosslinkable group in the molecule, the proportion of the structural unit containing the crosslinkable group in the crosslinkable acrylic polymer may be 1% by mass or more and 50% by mass or less.
When the above-mentioned crosslinkable acrylic polymer has an epoxy group as a crosslinkable group in the molecule, the proportion of the structural unit containing the epoxy group in the crosslinkable acrylic polymer may be 5% by mass or more and 50% by mass or less, or may be 7% by mass or more and 40% by mass or less.
The structural unit is a structure derived from each monomer after polymerization of a monomer (for example, 2-ethylhexyl acrylate, hydroxyethyl acrylate, etc.) when polymerizing a crosslinkable acrylic polymer. The same applies below.

When the above-mentioned crosslinkable acrylic polymer has an epoxy group as a crosslinkable group in the molecule, the epoxy equivalent of the crosslinkable acrylic polymer may be 1,300 [g/eq] or more and 4,200 [g/eq] or less, or may be 1,500 [g/eq] or more and 2,500 [g/eq] or less.
When the epoxy equivalent of the crosslinkable acrylic polymer is 1,300 [g/eq] or more, the die bond sheet 10 after the heat curing treatment can have better heat resistance. Also, when the epoxy equivalent of the crosslinkable acrylic polymer is 4,200 [g/eq] or less, the warping of the die bond sheet 10 due to the heat curing treatment can be further suppressed.

The epoxy equivalent of the above crosslinkable acrylic polymer is measured by a method conforming to JIS K7236:2001 (indicator titration method/potentiometric titration method).

The die bond sheet 10 of the present embodiment may contain one or more types of crosslinkable acrylic polymers.
At least two of the multiple crosslinkable acrylic polymers are capable of crosslinking with each other, that is, the crosslinkable groups of one crosslinkable acrylic polymer and the crosslinkable groups of the other crosslinkable acrylic polymer can crosslink with each other.

Different types of crosslinkable acrylic polymers have, for example, crosslinkable groups in the molecule that crosslink with each other. Specifically, a crosslinkable acrylic polymer having at least one of a hydroxy group or a carboxy group as a crosslinkable group in the molecule is different from a crosslinkable acrylic polymer having at least one of an epoxy group or an isocyanate group as a crosslinkable group in the molecule.
Alternatively, different types of crosslinkable acrylic polymers differ from each other in, for example, the types of monomer structural units contained in the molecule. Specifically, a crosslinkable acrylic polymer having a hydroxyl group-containing (meth)acrylic monomer and an alkyl (meth)acrylate monomer as structural units in the molecule is different from a crosslinkable acrylic polymer having a carboxyl group-containing (meth)acrylic monomer and an alkyl (meth)acrylate monomer as structural units in the molecule.

At least one of the crosslinkable acrylic polymers may have a mass average molecular weight of 10,000 or more and 400,000 or less. At least one of the crosslinkable acrylic polymers may have a mass average molecular weight of 20,000 or more and 350,000 or less, or may have a mass average molecular weight of 30,000 or more and 300,000 or less. Such a mass average molecular weight value is a value obtained by measuring the crosslinkable acrylic polymer by GPC.
When the mass average molecular weight of the crosslinkable acrylic polymer is 10,000 or more, there is an advantage that the sheet shape of the die bond sheet 10 can be more easily maintained. In addition, when the mass average molecular weight of the crosslinkable acrylic polymer is 400,000 or less, the die bond sheet 10 can exhibit better embeddability.

The weight average molecular weight is measured by gel permeation chromatography (GPC) under the following conditions.
Assumed device name (device example): Agilent product name "1200"
Detector: Differential refractive index (RI) detector Column: Three columns connected in series, Tosoh Corporation, product name "TSKgel SuperAWM-H / superAW4000 / superAW2500" (column diameter = 6 mm, column length = 15 cm)
Column temperature: 40°C
Flow rate: 0.4mL/min
Injection volume: 40 μL (eluent preparation solution with sample concentration of 0.1% by mass)
Standard material for creating calibration curve: polystyrene Data processing software: Waters product name "Empower3"
Eluent: Tetrahydrofuran (DMF) salt added. Measure number average molecular weight (Mn), mass average molecular weight (Mw), molecular weight distribution (Mw/Mn), etc.

The above crosslinkable acrylic polymer can be synthesized, for example, by a general polymerization method using a radical polymerization initiator.

As described above, the die bond sheet 10 of the present embodiment has a shear loss modulus G″ at 140° C. before the thermal curing treatment of 1 kPa or more and 20 kPa or less.
Such shear loss modulus G" may be 1.2 kPa or more, or may be 2.1 kPa or more. Moreover, such shear loss modulus G" may be 19.0 kPa or less, or may be 18.0 kPa or less.
When the shear loss modulus G'' is 1 kPa or more and 20 kPa or less, the die bond sheet 10 can exhibit good embedding properties (ability to conform to irregularities on the adherend surface) during die bonding, as described above.

The shear loss modulus G" of the die bond sheet 10 before the heat curing treatment can be increased, for example, by increasing the molecular weight of the crosslinkable acrylic polymer. On the other hand, the shear loss modulus G" can be decreased by decreasing the molecular weight of the crosslinkable acrylic polymer.

The shear loss modulus G″ is measured under the following conditions. The details of the measurement method will be described in the Examples.
Measurement equipment: Rheometer "Thermo SCIENTIFIC HAAKE MARS III"
Test sample size: 8 mm diameter x 300 μm thick cylinder Test temperature: 80°C to 160°C
Frequency: 1Hz
Heating rate: 5° C./min
Number of measurements: 3 (average value used)

As described above, the die bond sheet 10 of the present embodiment has a tensile modulus at 150° C. (tensile storage modulus E′) of 0.5 MPa or more and 7.0 MPa or less after heat curing treatment at 150° C. for 1 hour.
The tensile modulus may be 0.7 MPa or more, or 1.1 MPa or more. The tensile modulus may be 6.5 MPa or less, or 4.2 MPa or less.
Since the tensile elastic modulus is 0.5 MPa or more and 7.0 MPa or less, warping of the die bond sheet 10 after the thermal curing treatment can be suppressed.

The tensile modulus of the die bond sheet 10 can be increased, for example, by increasing the content ratio of the constituent units of the crosslinkable group-containing monomer that constitutes the above-mentioned crosslinkable acrylic polymer. On the other hand, the tensile modulus can be decreased, for example, by decreasing the content ratio of the constituent units of the crosslinkable group-containing monomer that constitutes the above-mentioned crosslinkable acrylic polymer.

The tensile modulus is measured under the following conditions. The details of the measurement method will be described in the Examples.
Measurement device: Solid viscoelasticity measurement device Size: Initial length 40 mm, width 10 mm
Heating rate: 10 ° C. / min,
Measurement temperature: 150°C in the temperature range of -30 to 280°C
Chuck distance: 22.5 mm
Frequency: 1Hz,
The value of the tensile storage modulus E' was taken as the above tensile modulus.

The glass transition point Tg of the die bond sheet 10 of the present embodiment may be 20° C. or more and 100° C. or less after a heat curing treatment at 150° C. for 1 hour.
Such a glass transition point Tg may be 25° C. or higher, or may be 31° C. or higher. Moreover, such a glass transition point Tg may be 95° C. or lower, or may be 90° C. or lower.
The above glass transition point Tg being 20° C. or higher has the advantage of increasing the adhesive strength of the die bond sheet 10 to the adherend. In addition, the above glass transition point Tg being 100° C. or lower can further suppress the internal stress of the die bond sheet 10 caused by the heat curing treatment, and therefore can further suppress the warping of the die bond sheet 10 caused by the heat curing treatment.

The glass transition temperature Tg of the die bond sheet 10 can be increased, for example, by increasing the content ratio of the constituent units of the crosslinkable group-containing monomer that constitutes the above-mentioned crosslinkable acrylic polymer, or by increasing the amount of the curing agent, etc., that is blended into the die bond sheet 10. On the other hand, the glass transition temperature Tg can be lowered, for example, by decreasing the content ratio of the constituent units of the crosslinkable group-containing monomer that constitutes the above-mentioned crosslinkable acrylic polymer, or by decreasing the amount of the curing agent, etc., that is blended into the die bond sheet 10.

In the die bond sheet 10 of the present embodiment, Tan δ at the glass transition point Tg measured as described above may be 0.7 or more and 1.5 or less.
Tan δ at the glass transition point Tg may be 0.75 or more, or may be 0.80 or more. Also, Tan δ at the glass transition point Tg may be 1.40 or less, or may be 1.35 or less.
When Tan δ at the above glass transition point Tg is 0.7 or more, the internal stress of the die bond sheet 10 that may be generated by the heat curing treatment can be further alleviated. In addition, when Tan δ at the above glass transition point Tg is 1.5 or less, there is an advantage that the heat resistance of the die bond sheet 10 becomes better.

The Tan δ at the glass transition point Tg of the die bond sheet 10 can be increased, for example, by increasing the content ratio of the constituent units of the crosslinkable group-containing monomer that constitutes the above-mentioned crosslinkable acrylic polymer, or by increasing the amount of the curing agent, etc., that is blended into the die bond sheet 10. On the other hand, the Tan δ at the glass transition point Tg can be lowered by decreasing the content ratio of the constituent units of the crosslinkable group-containing monomer that constitutes the above-mentioned crosslinkable acrylic polymer, or by decreasing the amount of the curing agent, etc., that is blended into the die bond sheet 10.

The above glass transition point Tg and Tan δ at the above glass transition point Tg are calculated based on the storage modulus E′ and loss modulus E″ obtained when measuring the above-mentioned tensile modulus.
The storage modulus E' and loss modulus E" are measured while increasing the temperature, and Tan δ is calculated for each temperature by the formula Tan δ=E"/E'. A higher Tan δ indicates a higher viscous property.
The temperature at which Tan δ is the largest (the apex of the portion where Tan δ shows a peak shape) is taken as the glass transition point Tg. Tan δ at the glass transition point Tg is also read.

In the die bond sheet 10 of this embodiment, the breaking elongation at 0°C may be 50% or less. Such breaking elongation may be 45% or less, or 40% or less. The breaking elongation may be 2% or more.

The breaking elongation is measured under the following conditions.
Measurement device: Tensile testing machine Size of test piece: Width 10 mm x Length 40 mm
Initial chuck distance: 10 mm
Temperature: 0°C
Tensile speed: 300 mm/min

The crosslinkable acrylic polymer preferably contains the largest amount of alkyl (meth)acrylate monomer units in the molecule by mass. Examples of the alkyl (meth)acrylate monomer include C2-C18 alkyl (meth)acrylate monomers in which the alkyl group (hydrocarbon group) has 2 to 18 carbon atoms.

Examples of alkyl (meth)acrylate monomers include saturated linear alkyl (meth)acrylate monomers, saturated branched alkyl (meth)acrylate monomers, and saturated cyclic alkyl (meth)acrylate monomers.

Examples of the saturated linear alkyl (meth)acrylate monomer include ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, n-decyl (meth)acrylate, tridecyl (meth)acrylate, lauryl (meth)acrylate, myristyl (meth)acrylate, palmityl (meth)acrylate, stearyl (meth)acrylate, etc. The number of carbon atoms in the linear alkyl group portion is preferably 2 or more and 8 or less.
Examples of the saturated branched alkyl (meth)acrylate monomer include isoheptyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, isodecyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc. The alkyl group portion may have any of an iso structure, a sec structure, a neo structure, or a tert structure.

The above-mentioned crosslinkable acrylic polymer contains constitutional units derived from a crosslinkable group-containing monomer copolymerizable with an alkyl (meth)acrylate monomer.
In this embodiment, the crosslinkable acrylic polymer is an acrylic polymer in which at least an alkyl (meth)acrylate monomer and a crosslinkable group-containing monomer are copolymerized. In other words, the crosslinkable acrylic polymer has a structure in which the constituent units of the alkyl (meth)acrylate monomer and the constituent units of the crosslinkable group-containing monomer are linked in a random order.

Examples of the crosslinkable group-containing monomer include functional group-containing monomers such as carboxy group-containing (meth)acrylic monomers, acid anhydride (meth)acrylic monomers, hydroxy group-containing (meth)acrylic monomers, epoxy group-containing (glycidyl group)-containing (meth)acrylic monomers, isocyanate group-containing (meth)acrylic monomers, sulfonic acid group-containing (meth)acrylic monomers, phosphoric acid group-containing (meth)acrylic monomers, acrylamide, and acrylonitrile. The crosslinkable group-containing monomers may have an ether group or an ester group in the molecule.

The crosslinkable acrylic polymer is preferably
at least one crosslinkable group-containing monomer selected from the group consisting of a carboxy group-containing (meth)acrylic monomer, a hydroxy group-containing (meth)acrylic monomer, an epoxy group-containing (meth)acrylic monomer, and an isocyanate group-containing (meth)acrylic monomer;
It is a copolymer of an alkyl (meth)acrylate (particularly, an alkyl (meth)acrylate having an alkyl portion with 8 or less carbon atoms).

Examples of carboxy group-containing (meth)acrylic monomers include (meth)acrylic acid, mono(2-(meth)acryloyloxyethyl)succinate monomers, etc. The carboxy group may be located at a terminal portion of the monomer structure, or may be bonded to a hydrocarbon other than the terminal portion.
Examples of hydroxy group-containing (meth)acrylic monomers include hydroxyethyl (meth)acrylate monomers, hydroxypropyl (meth)acrylate monomers, hydroxybutyl (meth)acrylate monomers, etc. The hydroxy group may be located at a terminal portion of the monomer structure, or may be bonded to a hydrocarbon other than the terminal portion.
Examples of epoxy group-containing (meth)acrylic monomers include glycidyl (meth)acrylate monomer, 4-hydroxybutyl (meth)acrylate glycidyl ether, etc. The epoxy group may be located at the terminal portion of the monomer structure, or may be bonded to a hydrocarbon other than the terminal portion.
An example of an isocyanate group-containing (meth)acrylic monomer is 2-methacryloyloxyethyl isocyanate.

In this embodiment, the crosslinkable acrylic polymer contains an epoxy group as a crosslinkable group, has a glycidyl (meth)acrylate structural unit having the epoxy group in the molecule, and the content of the glycidyl (meth)acrylate structural unit in the crosslinkable acrylic polymer is preferably 5% by mass or more and 50% by mass or less, and more preferably 7% by mass or more and 40% by mass or less.

The die bond sheet 10 may contain components other than the above-mentioned cross-linkable acrylic polymer. For example, the die bond sheet 10 may further contain at least one of a thermosetting resin or a thermoplastic resin other than the above-mentioned cross-linkable acrylic polymer.

Examples of thermosetting resins include epoxy resins, phenolic resins, amino resins, unsaturated polyester resins, polyurethane resins, silicone resins, and thermosetting polyimide resins. Only one type of the above thermosetting resins may be used, or two or more types may be used.

Examples of the epoxy resins include bisphenol A type, bisphenol F type, bisphenol S type, brominated bisphenol A type, hydrogenated bisphenol A type, bisphenol AF type, biphenyl type, naphthalene type, fluorene type, phenol novolac type, orthocresol novolac type, trishydroxyphenylmethane type, tetraphenylolethane type, hydantoin type, trisglycidyl isocyanurate type, and glycidylamine type epoxy resins.

Phenol resins can act as curing agents for epoxy resins. Examples of phenol resins include novolac-type phenol resins, resol-type phenol resins, and polyoxystyrenes such as polyparaoxystyrene.
Examples of novolac type phenolic resins include phenol novolac resins, phenol aralkyl resins (such as biphenyl aralkyl type resin phenolic resins), cresol novolac resins, tert-butylphenol novolac resins, nonylphenol novolac resins, and phenol xylylene resins.
The hydroxyl equivalent [g/eq] of the phenol resin may be, for example, 90 or more and 220 or less.
As the phenolic resin, a biphenyl aralkyl type resin having a relatively large hydroxyl group equivalent is preferable in that the elastic modulus of the die bond sheet 10 can be appropriately low.
As the phenolic resin, one kind or two or more kinds may be adopted.

In the present embodiment, the die bond sheet 10 may contain the above-mentioned crosslinkable acrylic polymer and the thermosetting resin which undergo a crosslinking reaction with each other. The die bond sheet 10 may also contain a plurality of types of crosslinkable acrylic polymers which undergo a crosslinking reaction with each other.
Preferably, the die bond sheet 10 contains an epoxy group-containing acrylic polymer or an isocyanate group-containing acrylic polymer as a crosslinkable acrylic polymer, and a phenol resin as a thermosetting resin, whereby the epoxy group or isocyanate group of the crosslinkable acrylic polymer and the hydroxyl group of the phenol resin undergo a crosslinking reaction to sufficiently harden the die bond sheet 10.
More preferably, the die bond sheet 10 contains an epoxy group-containing acrylic polymer as a crosslinkable acrylic polymer and a phenol resin as a thermosetting resin. This allows the epoxy group of the crosslinkable acrylic polymer and the hydroxyl group of the phenol resin to undergo a crosslinking reaction to sufficiently harden the die bond sheet 10. In this case, the hydroxyl equivalent of the phenol resin may be 160 or more and 250 or less.

In the die bond sheet 10, the hydroxyl groups of the phenolic resin are preferably 0.5 equivalents or more and 2.0 equivalents or less, more preferably 0.7 equivalents or more and 1.5 equivalents or less, per equivalent of the epoxy groups of the epoxy group-containing acrylic polymer. This allows the crosslinking reaction between the epoxy group-containing acrylic polymer and the phenolic resin to proceed sufficiently.

The die bond sheet 10 may contain a carboxy group-containing acrylic polymer or a hydroxy group-containing acrylic polymer as a crosslinkable acrylic polymer, and an epoxy resin as a thermosetting resin. This allows the carboxy group or hydroxy group of the crosslinkable acrylic polymer to undergo a crosslinking reaction with the epoxy group of the epoxy resin, thereby sufficiently curing the die bond sheet 10.

When the die bond sheet 10 contains a thermosetting resin such as an epoxy resin or a phenol resin, the content of such thermosetting resin in the die bond sheet 10 is preferably 35% by mass or less, and more preferably less than 32% by mass. This allows the die bond sheet 10 after the heat curing treatment to have a lower elastic modulus. Therefore, warping of the die bond sheet 10 due to the heat curing treatment can be further suppressed.

Examples of thermoplastic resins other than the above-mentioned crosslinkable functional group-containing acrylic polymer that may be included in the die bond sheet 10 include natural rubber, butyl rubber, isoprene rubber, chloroprene rubber, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, polybutadiene resin, polycarbonate resin, thermoplastic polyimide resin, polyamide resin such as 6-polyamide resin and 6,6-polyamide resin, phenoxy resin, acrylic resin that does not contain a crosslinkable functional group in the molecule, saturated polyester resin such as PET and PBT, polyamideimide resin, fluororesin, and the like.
As the thermoplastic resin, one kind or two or more kinds may be adopted.

The content ratio of the above-mentioned crosslinkable acrylic polymer to the total mass of the die bond sheet 10 is preferably 50 parts by mass or more and 100 parts by mass or less, more preferably 55 parts by mass or more, and even more preferably 60 parts by mass or more.

In the die bond sheet 10, the content ratio of the above-mentioned crosslinkable acrylic polymer is preferably 50 parts by mass or more and 100 parts by mass or less, more preferably 60 parts by mass or more and 95 parts by mass or less, and even more preferably 64 parts by mass or more, per 100 parts by mass of organic components other than the filler (for example, the above-mentioned crosslinkable acrylic polymer, thermosetting resin, curing catalyst, etc., silane coupling agent, dye). The organic components are components other than the filler. The elasticity and viscosity of the die bond sheet 10 can be adjusted by changing the content ratio of the thermosetting resin in the die bond sheet 10.
On the other hand, the content of the thermosetting resin may be 40 parts by mass or less per 100 parts by mass of the organic component.

The die bond sheet 10 may or may not contain a filler. By changing the amount of the filler in the die bond sheet 10, the elasticity and viscosity of the die bond sheet 10 can be more easily adjusted. Furthermore, the physical properties of the die bond sheet 10, such as electrical conductivity, thermal conductivity, and elastic modulus, can be adjusted.
The filler may be an inorganic filler or an organic filler, and the inorganic filler is preferred.
Examples of inorganic fillers include fillers containing aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, aluminum nitride, boron nitride, silica such as crystalline silica and amorphous silica, etc. Examples of the material of the inorganic filler include simple metals such as aluminum, gold, silver, copper, nickel, etc., and alloys, etc. Fillers such as aluminum borate whiskers, amorphous carbon black, graphite, etc. The shape of the filler may be various shapes such as spherical, needle-like, flake-like, etc. As the filler, only one of the above types or two or more types are used.

The average particle size of the filler may be, for example, 5 nm or more and 10 μm or less. The average particle size of the filler is preferably 5 nm or more and 500 nm or less, and more preferably 5 nm or more and 100 nm or less. When the average particle size is 5 nm or more, the wettability and adhesion to the adherend such as a semiconductor wafer are further improved. When the average particle size is 500 nm or less, the characteristics of the added filler can be more fully exhibited, and the heat resistance of the die bond sheet 10 can be further exhibited. The average particle size of the filler can be determined, for example, using a photometric particle size distribution meter (for example, product name "LA-910", manufactured by Horiba, Ltd.).

The specific surface area of the filler may be, for example, 35 m ² /g or more and 400 ^{m 2} /g or less. When the specific surface area is 35 m ² /g or more, the number of --OH groups on the inorganic filler surface is relatively large, and the crosslinking reaction due to the thermosetting reaction is more likely to proceed. In addition, highly active crosslinking groups such as epoxy groups are more likely to bond with the inorganic filler surface. On the other hand, when the specific surface area is 400 m ² /g or less, excessive bonding between highly active crosslinking groups such as epoxy groups and the inorganic filler surface can be suppressed. The specific surface area of the filler is calculated by the BET method in accordance with JIS Z8830:2013. Specifically, a sample is placed in a measurement cell, heated at 200°C for 30 minutes, and then cooled with liquid nitrogen. The specific surface area is calculated from the amount of gas when nitrogen is released due to the heat treatment performed.

When the die bond sheet 10 contains a filler, the filler content may be 50% by mass or less, 40% by mass or less, or 30% by mass or less of the total mass of the die bond sheet 10. The filler content may be, for example, 10% by mass or more.

Preferably, in the die bond sheet 10 of the present embodiment, the content of silica filler as an inorganic filler is 40 mass % or less (may be 0 mass %), and the specific surface area of the silica filler is 35 ^{m 2} /g or more and 400 m ² /g or less.

The die bond sheet 10 may contain other components as necessary. Examples of the other components include a curing catalyst, a flame retardant, a silane coupling agent, an ion trapping agent, and a dye.
Examples of the flame retardant include antimony trioxide, antimony pentoxide, and brominated epoxy resins.
Examples of the silane coupling agent include β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-glycidoxypropylmethyldiethoxysilane.
Examples of the ion trapping agent include hydrotalcites, bismuth hydroxide, and benzotriazole.
As the other additives, one kind may be used alone, or two or more kinds may be used in combination.

The die bond sheet 10 preferably contains the above-mentioned crosslinkable acrylic polymer, thermosetting resin, and filler, because the elasticity and viscosity can be easily adjusted.

The thickness of the die bond sheet 10 is not particularly limited, but is, for example, 1 μm or more and 200 μm or less. Such a thickness may be 3 μm or more and 150 μm or less, or 5 μm or more and 100 μm or less. Note that, when the die bond sheet 10 is a laminate, the above thickness is the total thickness of the laminate.

The die bond sheet 10 may have a single-layer structure, for example, as shown in Fig. 1. In this specification, a single layer means having only a layer formed of the same composition. A form in which a plurality of layers formed of the same composition are laminated is also a single layer.
On the other hand, the die bond sheet 10 may have a multi-layer structure in which layers formed of, for example, two or more different compositions are laminated. When the die bond sheet 10 has a multi-layer structure, at least one layer constituting the die bond sheet 10 may contain the above-mentioned cross-linkable acrylic polymer and may further contain a thermosetting resin as necessary.

Next, we will explain an embodiment of the dicing die bond film according to the present invention.

The dicing die bond film 1 of this embodiment comprises the above-mentioned die bond sheet 10 and a dicing tape attached to the die bond sheet 10.

In the dicing die bond film 1 of this embodiment, when used, the adhesive layer 22 is cured by irradiation with active energy rays (e.g., ultraviolet rays). In detail, in a state in which the die bond sheet 10 having a semiconductor wafer adhered to one side and the adhesive layer 22 bonded to the other side of the die bond sheet 10 are laminated, ultraviolet rays or the like are irradiated to at least the adhesive layer 22. For example, ultraviolet rays or the like are irradiated from the side where the base layer 21 is disposed, and the ultraviolet rays or the like reach the adhesive layer 22 after passing through the base layer 21. The adhesive layer 22 is cured by irradiation with ultraviolet rays or the like.
Since the adhesive layer 22 hardens after irradiation, the adhesive strength of the adhesive layer 22 can be reduced, so that the die bond sheet 10 (with the semiconductor wafer adhered thereto) can be relatively easily peeled off from the adhesive layer 22 after irradiation.

<Dicing tape for dicing die bond film>
The dicing tape 20 is usually a long sheet and is stored in a rolled state until it is used. The dicing die bond film 1 of the present embodiment is stretched on an annular frame having an inner diameter slightly larger than the silicon wafer to be cut, and is used after being cut.

The dicing tape 20 includes a base layer 21 and an adhesive layer 22 superimposed on the base layer 21.

The base material layer 21 may have a single-layer structure or a laminated structure.
Each layer of the base material layer 21 is, for example, a metal foil, a fiber sheet such as paper or cloth, a rubber sheet, or a resin film.
Examples of the fiber sheet constituting the base material layer 21 include paper, woven fabric, and nonwoven fabric.
Examples of materials for the resin film include polyolefins such as polyethylene (PE), polypropylene (PP), and ethylene-propylene copolymers; ethylene copolymers such as ethylene-vinyl acetate copolymers (EVA), ionomer resins, ethylene-(meth)acrylic acid copolymers, and ethylene-(meth)acrylic acid ester (random, alternating) copolymers; polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBT); polyacrylates; polyvinyl chloride (PVC); polyurethanes; polycarbonates; polyphenylene sulfide (PPS); polyamides such as aliphatic polyamides and fully aromatic polyamides (aramids); polyether ether ketones (PEEK); polyimides; polyetherimides; polyvinylidene chloride; ABS (acrylonitrile-butadiene-styrene copolymers); cellulose or cellulose derivatives; silicone-containing polymers; and fluorine-containing polymers. These may be used alone or in combination of two or more.

The base layer 21 is preferably made of a polymeric material such as a resin film.
When the base layer 21 has a resin film, the resin film may be subjected to a stretching process or the like to control the deformability such as elongation percentage.
The surface of the base layer 21 may be subjected to a surface treatment in order to enhance adhesion with the pressure-sensitive adhesive layer 22. Examples of the surface treatment that can be used include oxidation treatment by chemical or physical methods such as chromate treatment, ozone exposure, flame exposure, high-voltage shock exposure, and ionizing radiation treatment. In addition, the base layer 21 may be subjected to a coating treatment using a coating agent such as an anchor coating agent, a primer, or an adhesive.

The substrate layer 21 may be a single layer or may be composed of multiple layers (e.g., three layers). The thickness (total thickness) of the substrate layer 21 may be 80 μm or more and 150 μm or less.

The back side of the base material layer 21 (the side on which the adhesive layer 22 is not overlapped) may be subjected to a release treatment using a release agent (release agent) such as a silicone-based resin or a fluorine-based resin in order to impart releasability.
The base layer 21 is preferably a light-transmitting (ultraviolet ray-transmitting) resin film or the like, since this allows active energy rays such as ultraviolet ray to be applied to the pressure-sensitive adhesive layer 22 from the back side.

The dicing tape 20 may be provided with a release sheet that covers one side of the adhesive layer 22 (the side where the adhesive layer 22 does not overlap the base layer 21) before use. The release sheet is used to protect the adhesive layer 22, and is peeled off before the die bond sheet 10 is attached to the adhesive layer 22.

As the release sheet, for example, a plastic film or paper that has been surface-treated with a release agent such as a silicone-based, long-chain alkyl-based, fluorine-based, or molybdenum sulfide-based release agent can be used.
The release sheet can be used as a support material for supporting the adhesive layer 22. In particular, the release sheet is preferably used when the adhesive layer 22 is overlaid on the base layer 21. In detail, the adhesive layer 22 is overlaid on the base layer 21 in a state where the release sheet and the adhesive layer 22 are laminated, and after overlaying, the release sheet is peeled off (transferred), thereby overlaying the adhesive layer 22 on the base layer 21.

In the present embodiment, the pressure-sensitive adhesive layer 22 contains, for example, an acrylic polymer compound, an isocyanate compound, and a polymerization initiator.
The pressure-sensitive adhesive layer 22 may have a thickness of 5 μm or more and 40 μm or less. The shape and size of the pressure-sensitive adhesive layer 22 are usually the same as the shape and size of the base layer 21.

The acrylic polymer compound has at least an alkyl (meth)acrylate structural unit, a hydroxyl group-containing (meth)acrylate structural unit, and a polymerizable group-containing (meth)acrylate structural unit in the molecule. The structural units are units that constitute the main chain of the acrylic polymer compound. Each side chain in the acrylic polymer compound is included in each structural unit that constitutes the main chain.

In the acrylic polymer compound contained in the pressure-sensitive adhesive layer 22, the above-mentioned structural units can be confirmed by NMR analysis such as ¹ H-NMR and ¹³ C-NMR, pyrolysis GC/MS analysis, infrared spectroscopy, etc. The molar ratio of the above-mentioned structural units in the acrylic polymer compound is usually calculated from the blend amount (charge amount) when the acrylic polymer compound is polymerized.

The above alkyl (meth)acrylate structural unit is derived from an alkyl (meth)acrylate monomer. In other words, the molecular structure after the alkyl (meth)acrylate monomer is polymerized is the alkyl (meth)acrylate structural unit. The term "alkyl" refers to the number of carbon atoms in the hydrocarbon portion ester-bonded to (meth)acrylic acid.
The hydrocarbon portion of the alkyl portion in the structural unit of the alkyl (meth)acrylate may be a saturated hydrocarbon or an unsaturated hydrocarbon. The number of carbon atoms in the hydrocarbon portion may be 6 or more and 10 or less.

Examples of constituent units of alkyl (meth)acrylate include hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n- or iso-nonyl (meth)acrylate, and decyl (meth)acrylate.

The acrylic polymer compound has a hydroxyl group-containing (meth)acrylate structural unit, and the hydroxyl group of such a structural unit easily reacts with an isocyanate group.
By allowing an acrylic polymer compound having a hydroxyl group-containing (meth)acrylate structural unit and an isocyanate compound to coexist in the pressure-sensitive adhesive layer 22, the pressure-sensitive adhesive layer 22 can be appropriately cured. This allows the acrylic polymer compound to be sufficiently gelled. Thus, the pressure-sensitive adhesive layer 22 can exhibit its adhesive performance while maintaining its shape.

The structural unit of the hydroxyl group-containing (meth)acrylate is preferably a structural unit of a hydroxyl group-containing C2-C4 alkyl (meth)acrylate. The term "C2-C4 alkyl" refers to the number of carbon atoms in the hydrocarbon moiety that is ester-bonded to the (meth)acrylic acid. In other words, the hydroxyl group-containing C2-C4 alkyl (meth)acrylic monomer refers to a monomer in which (meth)acrylic acid is ester-bonded to an alcohol (usually a dihydric alcohol) having 2 to 4 carbon atoms.
The C2-C4 alkyl hydrocarbon portion is usually a saturated hydrocarbon. For example, the C2-C4 alkyl hydrocarbon portion is a linear saturated hydrocarbon or a branched saturated hydrocarbon. It is preferable that the C2-C4 alkyl hydrocarbon portion does not contain a polar group containing oxygen (O), nitrogen (N), or the like.

Examples of structural units of hydroxyl-containing C2-C4 alkyl (meth)acrylate include structural units of hydroxybutyl (meth)acrylate, such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxy n-butyl (meth)acrylate, or hydroxy iso-butyl (meth)acrylate. In the structural unit of hydroxybutyl (meth)acrylate, the hydroxyl group (-OH group) may be bonded to the carbon (C) at the end of the hydrocarbon portion, or to a carbon (C) other than the end of the hydrocarbon portion.

The acrylic polymer compound contains a structural unit of a polymerizable group-containing (meth)acrylate having a polymerizable unsaturated double bond in the side chain.
Since the acrylic polymer compound contains a structural unit of a polymerizable group-containing (meth)acrylate, the adhesive layer 22 can be cured by irradiation with active energy rays (such as ultraviolet rays) before the pick-up step. In detail, the irradiation with active energy rays such as ultraviolet rays generates radicals from the photopolymerization initiator, and the acrylic polymer compounds can be crosslinked by the action of these radicals. This allows the adhesive strength of the adhesive layer 22 before irradiation to be reduced by irradiation. Then, the die bond sheet 10 can be peeled off well from the adhesive layer 22.
The active energy rays include ultraviolet rays, radioactive rays, and electron beams.

Specifically, the structural unit of the polymerizable group-containing (meth)acrylate may have a molecular structure in which an isocyanate group of an isocyanate group-containing (meth)acrylic monomer is urethane-bonded to a hydroxyl group in the structural unit of the hydroxyl group-containing (meth)acrylate described above.

The structural unit of the polymerizable group-containing (meth)acrylate having a polymerizable group can be prepared after polymerization of an acrylic polymer compound. For example, after copolymerization of an alkyl (meth)acrylate monomer with a hydroxyl group-containing (meth)acrylic monomer, the hydroxyl group in a part of the structural unit of the hydroxyl group-containing (meth)acrylate and the isocyanate group of the isocyanate group-containing polymerizable monomer are reacted to form a urethane reaction, thereby obtaining the structural unit of the polymerizable group-containing (meth)acrylate.

The above-mentioned isocyanate group-containing (meth)acrylic monomer preferably has one isocyanate group and one (meth)acryloyl group in the molecule. An example of such a monomer is 2-methacryloyloxyethyl isocyanate.

The adhesive layer 22 of the dicing tape 20 in this embodiment further contains an isocyanate compound. A part of the isocyanate compound may be in a state after being reacted by a urethane reaction or the like.
The isocyanate compound has a plurality of isocyanate groups in the molecule. The isocyanate compound has a plurality of isocyanate groups in the molecule, which allows a crosslinking reaction between the acrylic polymer compounds in the pressure-sensitive adhesive layer 22 to proceed. In detail, one isocyanate group of the isocyanate compound is reacted with a hydroxyl group of an acrylic polymer compound, and the other isocyanate group is reacted with a hydroxyl group of another acrylic polymer compound, thereby allowing a crosslinking reaction via the isocyanate compound to proceed.

Examples of isocyanate compounds include diisocyanates such as aliphatic diisocyanates, alicyclic diisocyanates, and araliphatic diisocyanates.

Further examples of isocyanate compounds include polymerized polyisocyanates such as diisocyanate dimers and trimers, and polymethylene polyphenylene polyisocyanates.

In addition, the isocyanate compound may be, for example, a polyisocyanate obtained by reacting an excess amount of the above-mentioned isocyanate compound with an active hydrogen-containing compound. Examples of the active hydrogen-containing compound include an active hydrogen-containing low molecular weight compound and an active hydrogen-containing high molecular weight compound.
As the isocyanate compound, allophanated polyisocyanate, biuretized polyisocyanate, etc. can also be used.
The above isocyanate compounds may be used alone or in combination of two or more.

The above-mentioned isocyanate compound is preferably a reaction product of an aromatic diisocyanate and an active hydrogen-containing low molecular weight compound. The reaction rate of the isocyanate group in the reaction product of an aromatic diisocyanate is relatively slow, so that the pressure-sensitive adhesive layer 22 containing such a reaction product is prevented from being excessively hardened. The above-mentioned isocyanate compound is preferably one having three or more isocyanate groups in the molecule.

The polymerization initiator contained in the adhesive layer 22 is a compound that can initiate a polymerization reaction by the energy of heat or light applied. By containing the polymerization initiator in the adhesive layer 22, when heat energy or light energy is applied to the adhesive layer 22, a crosslinking reaction between acrylic polymer compounds can be promoted. In detail, a polymerization reaction between polymerizable groups between acrylic polymer compounds having a structural unit of a polymerizable group-containing (meth)acrylate can be initiated to harden the adhesive layer 22. This reduces the adhesive force of the adhesive layer 22, and in the pick-up process, the die bond sheet 10 can be easily peeled off from the hardened adhesive layer 22.
As the polymerization initiator, for example, a photopolymerization initiator or a thermal polymerization initiator is used. As the polymerization initiator, a general commercially available product can be used.

The adhesive layer 22 may further contain other components in addition to the components described above. Examples of the other components include tackifiers, plasticizers, fillers, antioxidants, antioxidants, UV absorbers, light stabilizers, heat stabilizers, antistatic agents, surfactants, and light release agents. The types and amounts of the other components used may be appropriately selected depending on the purpose.

The dicing die bond film 1 of the present embodiment may be provided with a release sheet that covers one surface of the die bond sheet 10 (the surface where the die bond sheet 10 does not overlap with the pressure-sensitive adhesive layer 22) before use. The release sheet is used to protect the die bond sheet 10, and is peeled off immediately before attaching an adherend (e.g., a semiconductor wafer) to the die bond sheet 10.
This release sheet can be used as a support material for supporting the die bond sheet 10. The release sheet is suitably used when overlaying the die bond sheet 10 on the adhesive layer 22. In detail, the die bond sheet 10 is overlaid on the adhesive layer 22 in a state in which the release sheet and the die bond sheet 10 are laminated, and after overlaying, the release sheet is peeled off (transferred), thereby overlaying the die bond sheet 10 on the adhesive layer 22.

Next, we will explain the manufacturing method of the die bond sheet 10 and dicing die bond film 1 of this embodiment.

<Dicing die bond film manufacturing method>
The manufacturing method of the dicing die bond film 1 of this embodiment is as follows:
A step of producing a die bond sheet 10;
A step of preparing a dicing tape 20;
The method includes a step of overlapping the manufactured die bond sheet 10 and the dicing tape 20.

<Step of Producing Die Bond Sheet (Thermosetting Resin Sheet)>
The process of producing the die bond sheet 10 includes the following steps:
A resin composition preparation step of preparing a resin composition for forming the die bond sheet 10;
and a die-bonding sheet forming step of forming the die-bonding sheet 10 from the resin composition.

In the resin composition preparation step, for example, the above-mentioned crosslinkable acrylic polymer is mixed with either an epoxy resin, an epoxy resin curing catalyst, a phenolic resin, or a solvent, and each resin is dissolved in the solvent to prepare the resin composition. The viscosity of the composition can be adjusted by changing the amount of the solvent. Commercially available products can be used as these resins.

In the die bond sheet forming process, for example, the resin composition prepared as described above is applied to a release sheet. The application method is not particularly limited, and general application methods such as roll coating, screen coating, and gravure coating are used. Next, if necessary, the applied composition is solidified by a desolvation process or a curing process to form the die bond sheet 10.

<Process for producing dicing tape>
The process for producing the dicing tape includes the following steps:
A synthesis step of synthesizing an acrylic polymer compound;
a pressure-sensitive adhesive layer preparation step of preparing a pressure-sensitive adhesive layer 22 by volatilizing a solvent from a pressure-sensitive adhesive composition containing the above-mentioned acrylic polymer compound, an isocyanate compound, a polymerization initiator, a solvent, and other components appropriately added depending on the purpose;
a base material layer preparation step of preparing a base material layer 21;
The method includes a lamination step of laminating the adhesive layer 22 and the base layer 21 together to laminate the base layer 21 and the adhesive layer 22 together.

In the synthesis step, for example, a C9 to C11 alkyl (meth)acrylate monomer having a carbon number of 9 or more and 11 or less in the hydrocarbon portion and a hydroxyl group-containing (meth)acrylic monomer are radically polymerized to synthesize an acrylic polymer compound intermediate.
The radical polymerization can be carried out by a general method. For example, the above-mentioned monomers are dissolved in a solvent, stirred while heating, and a polymerization initiator is added to synthesize an acrylic polymer compound intermediate. In order to adjust the molecular weight of the acrylic polymer compound, the polymerization may be carried out in the presence of a chain transfer agent.
Next, some of the hydroxyl groups of the structural units of the hydroxyl group-containing (meth)acrylate contained in the acrylic polymer compound intermediate are bonded to the isocyanate groups of the isocyanate group-containing polymerizable monomer by a urethane reaction, whereby some of the structural units of the hydroxyl group-containing (meth)acrylate become structural units of the polymerizable group-containing (meth)acrylate.
The urethanization reaction can be carried out by a general method. For example, an acrylic polymer compound intermediate and an isocyanate group-containing polymerizable monomer are stirred while being heated in the presence of a solvent and a urethanization catalyst. This allows the isocyanate group of the isocyanate group-containing polymerizable monomer to be urethane-bonded to a part of the hydroxyl groups of the acrylic polymer compound intermediate.

In the adhesive layer preparation process, for example, an acrylic polymer compound, an isocyanate compound, and a polymerization initiator are dissolved in a solvent to prepare an adhesive composition. The viscosity of the composition can be adjusted by changing the amount of solvent. Next, the adhesive composition is applied to a release sheet. As the application method, for example, a general application method such as roll coating, screen coating, or gravure coating is used. The applied composition is subjected to a solvent removal process, a solidification process, or the like to solidify the applied adhesive composition, thereby preparing the adhesive layer 22.

In the substrate layer preparation process, the substrate layer can be prepared by film formation using a general method. Examples of the film formation method include a calendar film formation method, a casting method in an organic solvent, an inflation extrusion method in a closed system, a T-die extrusion method, and a dry lamination method. A co-extrusion molding method may also be used. Note that a commercially available film or the like may also be used as the substrate layer 21.

In the lamination step, the pressure-sensitive adhesive layer 22 overlapping the release sheet is laminated on the base layer 21. The release sheet may remain overlapping the pressure-sensitive adhesive layer 22 until use.
In addition, in order to promote the reaction between the crosslinking agent and the acrylic polymer compound and also between the crosslinking agent and the surface portion of the base material layer 21, an aging treatment step may be carried out for 48 hours in an environment of 50°C after the lamination step.

Through these steps, the dicing tape 20 can be manufactured.

<Step of overlapping the die bond sheet 10 and the dicing tape 20>
In the step of overlapping the die bond sheet 10 and the dicing tape 20, the die bond sheet 10 is attached to the adhesive layer 22 of the dicing tape 20 manufactured as described above.

In such bonding, the release sheets are peeled off from the adhesive layer 22 of the dicing tape 20 and the die bond sheet 10, respectively, and the die bond sheet 10 and the adhesive layer 22 are bonded together so that they are in direct contact with each other. For example, the bonding can be performed by pressure bonding. The temperature during bonding is not particularly limited, and is, for example, 30° C. or higher and 50° C. or lower, and preferably 35° C. or higher and 45° C. or lower. The linear pressure during bonding is not particularly limited, and is preferably 0.1 kgf/cm or higher and 20 kgf/cm or lower, and more preferably 1 kgf/cm or higher and 10 kgf/cm or lower.
Prior to the above-mentioned application, the adhesive layer 22 of the dicing tape 20 may be irradiated with ultraviolet light or the like to harden the adhesive layer 22 to some extent. This allows the adhesive strength of the adhesive layer 22 to be appropriately reduced, improving the storage stability of the adhesive layer 22 and thus improving the pick-up properties when picking up a semiconductor chip.

The dicing die bond film 1 manufactured as described above through the above-mentioned process is used, for example, as an auxiliary tool for manufacturing a semiconductor device (semiconductor integrated circuit). The thermosetting resin sheet of this embodiment is used as a die bond sheet for bonding the chip to the adherend by placing it between a chip cut from a wafer on which a circuit surface is formed and an adherend in a method for manufacturing a semiconductor device. Specific examples of the use of the dicing die bond film 1 are described below.

<Method of using dicing die bond film when manufacturing semiconductor device>
A method for manufacturing a semiconductor device generally includes a process of cutting out chips from a semiconductor wafer having a circuit surface formed thereon, and assembling the chips.
This process includes, for example, a stealth dicing process in which a weak portion is formed by laser light inside a semiconductor wafer to which a backgrind tape has been attached, and the semiconductor wafer is prepared for processing into chips (dies) by a fracturing process; a backgrinding process in which the semiconductor wafer to which the backgrind tape has been attached is ground to reduce its thickness; a mounting process in which one side of the thinned semiconductor wafer (for example, the side opposite to the circuit side) is attached to a die bond sheet 10 and the semiconductor wafer is fixed to the dicing tape 20; and a process in which the dicing tape 20 is stretched to fractur e the semiconductor wafer to produce chips (dies). The dicing process includes an expanding process for expanding the gap between the chips by peeling the die bond sheet 10 and the adhesive layer 22, a pick-up process for removing the semiconductor chip (die) with the die bond sheet 10 attached, a die bond process for bonding the die bond sheet 10 attached to the semiconductor chip (die) to an adherend, a curing process for hardening the die bond sheet 10 attached to the adherend, a wire bonding process for electrically connecting the electrodes of the electronic circuit in the semiconductor chip (die) to the adherend by wires, and a sealing process for sealing the semiconductor chip (die) and wires on the adherend with a thermosetting resin. When carrying out these processes, the dicing tape (dicing die bond film) of this embodiment is used as a manufacturing auxiliary tool.

The stealth dicing process is a process in the so-called SDBG (Stealth Dicing Before Grinding) process. In the stealth dicing process, as shown in Figures 2A to 2C, a weak part for cutting a semiconductor device into small pieces (dies) is formed inside the semiconductor wafer W. More specifically, a backgrind tape G is attached to the circuit surface of the semiconductor wafer W (see Figure 2A). With the backgrind tape G attached, the semiconductor wafer W is subjected to a grinding process (pre-backgrinding process) using a grinding pad K until it reaches a predetermined thickness (see Figure 2B). A weak part is formed inside the semiconductor wafer W by irradiating the thinned semiconductor wafer W with laser light (see Figure 2C).

Instead of the stealth dicing process, a half-cut process may be performed. The half-cut process is a process in a so-called DBG (Dicing Before Grinding) process.
In the half-cut process, a groove is formed in the semiconductor wafer in order to process the semiconductor wafer into chips (dies) by a fracturing process, and then the semiconductor wafer is ground to reduce its thickness.
Specifically, in the half-cut process, a half-cut process is performed to divide the semiconductor device into small pieces (dies). More specifically, a wafer processing tape is attached to the surface of the semiconductor wafer opposite to the circuit surface. A dicing ring is also attached to the wafer processing tape. With the wafer processing tape attached, grooves for division are formed. A backgrind tape is attached to the surface with the grooves formed, while the wafer processing tape that was initially attached is peeled off.

As described above, the die bond sheet and dicing die bond film of this embodiment are preferably used in the SDBG (Stealth Dicing Before Grinding) process or DBG (Dicing Before Grinding) process for manufacturing semiconductor chips by cleaving a semiconductor wafer.

In the backgrinding process, as shown in FIG. 2D, the semiconductor wafer W with the backgrind tape G attached thereto is further ground to reduce the thickness of the semiconductor wafer W to the thickness of the chip (die) that will be produced later by fracturing.

In the mounting process, as shown in Figures 3A and 3B, the semiconductor wafer W is fixed to the dicing tape 20. More specifically, a dicing ring R is attached to the adhesive layer 22 of the dicing tape 20, and the semiconductor wafer W, whose thickness has been reduced by the above-mentioned cutting process, is attached to the exposed surface of the die bond sheet 10 (see Figure 3A). Next, the backgrind tape G is peeled off from the semiconductor wafer W (see Figure 3B).

In the expanding step, as shown in Figures 4A to 4C, the gap between the semiconductor chips (dies) X produced by cleaving is expanded. In detail, after a dicing ring R is attached to the adhesive layer 22 of the dicing tape 20, it is fixed to a holder H of an expanding device (see Figure 4A). A push-up member U provided in the expanding device is pushed up from the lower side of the dicing die bond film 1, so that the dicing die bond film 1 is stretched so as to be expanded in the surface direction (see Figure 4B). As a result, the semiconductor wafer W is cleaved under a specific temperature condition. The above temperature condition is, for example, -20°C or higher and 0°C or lower, preferably -15°C or higher and 0°C or lower, more preferably -10°C or higher and -5°C or lower. The expanded state is released by lowering the push-up member U (see Figure 4C, low-temperature expanding step up to this point).
5A and 5B, the dicing tape 20 is stretched so as to expand its area under higher temperature conditions (e.g., 10° C. to 25° C.), thereby separating adjacent semiconductor chips X after cleavage in the planar direction of the film surface and further widening the kerf (spacing) (room temperature expansion process).

In the pick-up process, as shown in FIG. 6, the semiconductor chip X with the die bond sheet 10 attached thereto is peeled off from the adhesive layer 22 of the dicing tape 20. More specifically, the pin member P is raised to push up the semiconductor chip X to be picked up through the dicing tape 20. The pushed-up semiconductor chip X is held by the suction jig J.

In the die bonding process, as shown in Fig. 7, the semiconductor chip X with the die bond sheet 10 attached thereto is bonded to an adherend Z. In the die bonding process, the semiconductor chips X with the die bond sheet 10 attached thereto may be stacked multiple times, for example, as shown in Fig. 9. In this way, the die bond sheet 10 may be used to embed the semiconductor chip when manufacturing a chip-embedded type semiconductor device (FOD [Film on Die] type semiconductor device).
In this case, the die bond sheet 10 used to embed the semiconductor chip is adhered to an uneven surface of an adherend. When the die bond sheet 10 is adhered to the uneven surface, the die bond sheet 10 needs to deform so as to fill the recesses. That is, the die bond sheet 10 needs to follow the uneven shape. If this conformability is poor, a gap (gap) V may occur, for example, as shown in FIG. 8.
Since the die bond sheet 10 of the present embodiment has the above-mentioned excellent embedding property, the occurrence of such a gap V can be suppressed.

In the curing process, a heat treatment is performed at a temperature of, for example, 80°C or higher and 175°C or lower in order to increase the reaction activity of the crosslinkable groups (e.g., epoxy groups) in the above-mentioned crosslinkable acrylic polymer contained in the die bond sheet 10 and promote the hardening of the die bond sheet 10.

9, in the wire bonding process, a semiconductor chip X (die) and an adherend Z are connected with a wire L while being heated. Thus, the crosslinkable group in the above-mentioned crosslinkable acrylic polymer contained in the die bond sheet 10 becomes reactive again by heating, and the curing reaction of the die bond sheet 10 can proceed.
In the wire bonding step, a compressive force may be applied to the die bond sheet 10 in the thickness direction.

In the sealing process, as shown in FIG. 10, the semiconductor chip X (die) and the die bond sheet 10 are sealed with a thermosetting resin M such as epoxy resin. In the sealing process, a heat treatment is performed at a temperature of, for example, 150° C. or higher and 200° C. or lower to promote the curing reaction of the thermosetting resin M.

In recent years, with the further development of integration technology in the semiconductor industry, thinner semiconductor chips (e.g., 20 μm to 50 μm thick) and thinner die bond sheets (e.g., 1 μm to 40 μm thick, preferably 7 μm thick, more preferably 5 μm thick) are in demand. Thinner adherends are also in demand.
An electronic circuit is formed on one surface of such a thin semiconductor chip. When an electronic circuit is formed on one surface of a thin semiconductor chip, the semiconductor chip cannot withstand the internal stress and may be slightly deformed (warped, etc.) as shown in FIG. 11, and this deformation may also cause deformation (warped, etc.) in the die bond sheet 10''.
When stacking is performed multiple times as described above with the die bond sheet attached to such a semiconductor chip, a so-called floating may occur due to poor adhesion between the die bond sheet and the chip (die).
As described above, the die bond sheet may also warp due to the internal stress of the die bond sheet caused by the thermal curing treatment. Therefore, the thinner the adherend and the semiconductor chip bonded to the die bond sheet are, the more likely the adherend and the semiconductor chip are to warp.
Since the die bond sheet 10 of the present embodiment has specific physical properties, it is possible to suppress the above-mentioned lifting, and also possible to suppress the phenomenon of warping of the adherend and the semiconductor chip.

The thermosetting resin sheet (die bond sheet) and dicing die bond film of this embodiment are as exemplified above, but the present invention is not limited to the die bond sheet and dicing die bond film exemplified above.
That is, various forms used in general die bond sheets and dicing die bond films can be adopted within the scope that does not impair the effects of the present invention.

The matters disclosed in this specification include the following.
(1)
The composition includes a crosslinkable acrylic polymer having a crosslinkable group in the molecule that undergoes a crosslinking reaction by a heat curing treatment,
A die bond sheet (thermosetting resin sheet) having a shear loss modulus G" of 1 kPa or more and 20 kPa or less at 140°C before heat curing treatment, and having a tensile modulus of 0.5 MPa or more and 7.0 MPa or less at 150°C after heat curing treatment at 150°C for 1 hour.
(2)
The die bond sheet (thermosetting resin sheet) according to the above (1), wherein the content ratio of the crosslinkable acrylic polymer relative to 100 parts by mass of an organic component contained in the die bond sheet is 50 parts by mass or more and 100 parts by mass or less.
(3)
The die bond sheet (thermosetting resin sheet) according to the above (1) or (2), wherein the glass transition point Tg after heat curing treatment at 150 ° C. for 1 hour is 20 ° C. or more and 100 ° C. or less, and Tan δ at the glass transition point Tg is 0.7 or more and 1.5 or less.
(4)
the crosslinkable group comprises an epoxy group,
the crosslinkable acrylic polymer has a structural unit of the glycidyl (meth)acrylate having an epoxy group in the molecule,
The die bond sheet (thermosetting resin sheet) according to any one of (1) to (3) above, wherein the content of the structural unit in the crosslinkable acrylic polymer is 5% by mass or more and 50% by mass or less.
(5)
The content of silica filler as an inorganic filler is 40 mass% or less,
The die-bonding sheet (thermosetting resin sheet) according to any one of the above (1) to (4), wherein the specific surface area of the silica filler is 35 m ² /g or more and 400 m ² /g or less.
(6)
a phenolic resin that undergoes a crosslinking reaction with the crosslinkable group by the thermal curing treatment,
The die bond sheet (thermosetting resin sheet) according to any one of (1) to (5) above, wherein the phenol resin has a hydroxyl group equivalent of 160 or more.
(7)
The die bond sheet (thermosetting resin sheet) according to any one of (1) to (6) above, comprising one or more crosslinkable acrylic polymers, and at least one of the crosslinkable acrylic polymers having a mass average molecular weight of 10,000 or more and 400,000 or less.
(8)
The die bond sheet (thermosetting resin sheet) according to any one of (1) to (7) above, which is used by being stuck to a dicing tape.
(9)
The die bond sheet (thermosetting resin sheet) according to any one of (1) to (8) above, having a breaking elongation at 0° C. of 50% or less.
(10)
A die bond sheet (thermosetting resin sheet) according to any one of (1) to (9) above, which is used in a Stealth Dicing Before Grinding (SDBG) process or a Dicing Before Grinding (DBG) process for manufacturing semiconductor chips by cleaving a semiconductor wafer.
(11)
The die bond sheet (thermosetting resin sheet) according to any one of (1) to (10) above, which contains at least one of an epoxy group-containing acrylic polymer and an isocyanate group-containing acrylic polymer as the crosslinkable acrylic polymer.
(12)
The die bond sheet (thermosetting resin sheet) according to (11) above, further comprising at least one of a phenolic resin as a thermosetting resin and a silica filler as an inorganic filler.
(13)
The die bond sheet (thermosetting resin sheet) according to any one of (1) to (11), comprising at least one of an epoxy group-containing acrylic polymer and an isocyanate group-containing acrylic polymer, and at least one of a hydroxy group-containing acrylic polymer and a carboxy group-containing acrylic polymer, as the crosslinkable acrylic polymer.
(14)
A dicing die bond film comprising the die bond sheet according to any one of (1) to (13) above and a dicing tape attached to the die bond sheet.

Next, the present invention will be described in more detail with reference to experimental examples, but the present invention is not limited to these.

A die bond sheet was produced as follows. This die bond sheet was then attached to a dicing tape to produce a dicing die bond film.

<Preparation of dicing tape>
The following raw materials were placed in a reaction vessel equipped with a cooling tube, a nitrogen inlet tube, a thermometer and a stirrer. Polymerization was carried out in a nitrogen stream at 60° C. for 10 hours to obtain an acrylic polymer compound A.
2-Ethylhexyl acrylate (2EHA): 100 parts by mass,
26 parts by weight of 2-hydroxyethyl acrylate (HEA),
Benzoyl peroxide: 0.4 parts by weight,
Toluene: 80 parts by mass,
1.2 parts by mass of 2-methacryloyloxyethyl isocyanate (hereinafter also referred to as MOI) was added to the liquid containing the acrylic polymer compound A obtained by polymerization as described above. Then, an addition reaction treatment was carried out in an air stream at 50° C. for 60 hours to obtain an acrylic polymer compound A′.
Next, the following ingredients were added to 100 parts of the acrylic polymer compound A' to prepare a pressure-sensitive adhesive solution.
Polyisocyanate compound: 1.6 parts by mass (product name "Coronate L", manufactured by Nippon Polyurethane Co., Ltd.)
Photopolymerization initiator: 3 parts by mass (product name "Irgacure 184", manufactured by Ciba Specialty Chemicals)
The adhesive solution prepared as described above was applied onto the treated surface of a silicone-treated PET release liner and dried by heating at 120° C. for 2 minutes to form an adhesive layer having a thickness of 10 μm.
Next, the pressure-sensitive adhesive layer surface and a substrate layer (EVA film (thickness: 115 μm) manufactured by Gunze Co., Ltd.) were attached to each other and stored at 23° C. for 72 hours to produce a dicing tape.

<Preparation of die bond sheet (thermosetting resin sheet)>
Example 1
An epoxy group-containing acrylic polymer (mass average molecular weight Mw=130,000) was polymerized using the following monomer composition.
Glycidyl methacrylate (GMA): 32% by mass
Ethyl acrylate (EA): 32% by mass
Butyl methacrylate (BMA): 36% by mass
For 100 parts by mass of the epoxy group-containing acrylic polymer polymerized in the above composition,
Phenol resin: 11 parts by mass (hydroxyl equivalent 203 [g/eq])
(Product name "MEHC-7851H" manufactured by Meiwa Chemical Industry Co., Ltd., biphenyl aralkyl type resin phenolic resin),
Silica filler: 23 parts by mass (specific surface area: 200 [m ² /g])
(Product name: "MEK-ST-40" manufactured by Nissan Chemical)
and methyl ethyl ketone were mixed to prepare an adhesive composition solution having a solid content concentration of 20 mass %.
The prepared adhesive composition solution was applied onto a release-treated film made of a silicone release-treated polyethylene terephthalate film having a thickness of 50 μm as a release liner (separator), and then dried at 130° C. for 2 minutes to prepare a die-bonding sheet having a thickness (average thickness) of 20 μm.

Example 2
An epoxy group-containing acrylic polymer (mass average molecular weight Mw=40,000) was polymerized using the following monomer composition.
Glycidyl methacrylate (GMA): 40% by mass
Ethyl acrylate (EA): 28% by mass
Butyl methacrylate (BMA): 32% by mass
For 100 parts by mass of the epoxy group-containing acrylic polymer polymerized in the above composition,
Silica filler: 42 parts by mass (specific surface area 200 [m ² /g])
(Product name: "MEK-ST-40" manufactured by Nissan Chemical Industries, Ltd.)
and methyl ethyl ketone were mixed to prepare an adhesive composition solution having a solid content concentration of 20 mass %.
Furthermore, a die-bonding sheet having a thickness (average thickness) of 20 μm was prepared from the adhesive composition solution by the same method as above.

Example 3
An epoxy group-containing acrylic polymer (mass average molecular weight Mw=320,000) was polymerized using the following monomer composition.
Glycidyl methacrylate (GMA): 7% by mass
Ethyl acrylate (EA): 48% by mass
Butyl methacrylate (BMA): 45% by mass
For 100 parts by mass of the epoxy group-containing acrylic polymer polymerized in the above composition,
Phenolic resin: 55 parts by mass (hydroxyl equivalent 173 [g/eq])
(Product name: MEHC-7800H, phenol xylylene resin manufactured by Meiwa Kasei Co., Ltd.)
Silica filler: 42 parts by mass (specific surface area: 60 [m ² /g])
(Product name: "MEK-AC-4130Y" manufactured by Nissan Chemical Industries, Ltd.)
and methyl ethyl ketone were mixed to prepare an adhesive composition solution having a solid content concentration of 20 mass %.
Furthermore, a die-bonding sheet having a thickness (average thickness) of 20 μm was prepared from the adhesive composition solution by the same method as above.

Example 4
An epoxy group-containing acrylic polymer (mass average molecular weight Mw=320,000) was polymerized using the following monomer composition.
Glycidyl methacrylate (GMA): 7% by mass
Ethyl acrylate (EA): 48% by mass
Butyl methacrylate (BMA): 45% by mass
Separately, a carboxyl group-containing acrylic polymer (mass average molecular weight Mw=30,000) was polymerized using the following monomer composition.
Acrylic acid (AA): 1% by mass
Butyl acrylate (BA): 32% by mass
Ethyl acrylate (EA): 23% by mass
Methyl methacrylate (MMA): 44% by mass
For 100 parts by mass of the epoxy group-containing acrylic polymer polymerized in the above composition,
Carboxy group-containing acrylic polymer polymerized with the above composition: 64 parts by mass,
and methyl ethyl ketone were mixed to prepare an adhesive composition solution having a solid content concentration of 20 mass %.
Furthermore, a die-bonding sheet having a thickness (average thickness) of 20 μm was prepared from the adhesive composition solution by the same method as above.

(Comparative Example 1)
- Acrylic resin: 100 parts by mass (contains OH group, mass average molecular weight Mw = 450,000)
(Product name “W248” manufactured by Negami Kogyo Co., Ltd.)
Phenol resin: 77 parts by mass (hydroxyl equivalent: 105 [g/eq])
(Product name: "MEHC-7500" manufactured by Meiwa Kasei Co., Ltd.)
Epoxy resin: 83 parts by mass (product name "EPPN501HY" manufactured by Nippon Kayaku Co., Ltd.)
Silica filler: 222 parts by mass (solid content equivalent) (specific surface area: 34 [m ² /g])
(Product name: MEK-AC-5140Z, manufactured by Nissan Chemical Industries, Ltd.)
and methyl ethyl ketone to prepare an adhesive composition solution having a solids concentration of 20 mass %.
Furthermore, a die-bonding sheet having a thickness (average thickness) of 20 μm was prepared from the adhesive composition solution by the same method as above.

(Comparative Example 2)
- Acrylic resin: 100 parts by mass (contains OH group, mass average molecular weight Mw = 450,000)
(Product name “W248” manufactured by Negami Kogyo Co., Ltd.)
Phenol resin: 279 parts by mass (hydroxyl equivalent 105 [g/eq])
(Product name: "MEHC-7500" manufactured by Meiwa Kasei Co., Ltd.)
Epoxy resin: 287 parts by mass (product name "EPPN501HY" manufactured by Nippon Kayaku Co., Ltd.)
Silica filler: 470 parts by mass (solid content equivalent) (specific surface area: 5 [m ² /g])
(Product name: SO-25R, manufactured by Admatechs)
and methyl ethyl ketone to prepare an adhesive composition solution having a solids concentration of 20 mass %.
Furthermore, a die-bonding sheet having a thickness (average thickness) of 20 μm was prepared from the adhesive composition solution by the same method as above.

<Production of dicing die bond film>
The die bond sheet of each Example and Comparative Example was laminated onto the adhesive layer of the dicing tape using a hand roller to produce a dicing die bond film.

<Measurement of physical properties of die bond sheet>
The physical properties of the die bond sheets of the respective Examples and Comparative Examples were measured as follows.

(Shear loss modulus G")
Details of the method for measuring the shear loss modulus G" are as follows. A viscoelasticity measuring device (Model ARES, manufactured by Rheometric Scientific) was used as the measuring device. A test piece of the die bond sheet was prepared by punching out a cylindrical shape with a diameter of 7.5 mm and a thickness of 1 mm. When a shear vibration with a frequency of 1 Hz was applied to one circular surface of the test piece at a temperature of 140°C, the shear vibration transmitted to the other circular surface was measured. The measured value was analyzed to obtain the shear loss modulus G". The measurement results are shown in Table 1.

(Measurement of tensile modulus at 150° C., glass transition point Tg, and Tan δ at Tg)
The die bond sheet was subjected to a curing treatment at 150° C. for 1 hour, and then the tensile storage modulus of the die bond sheet was measured at 150° C. As the measuring device, a solid viscoelasticity measuring device (model RSAIII, manufactured by Rheometric Scientific Co., Ltd.) was used.
A test piece having a length of 40 mm (measurement length) and a width of 10 mm was cut out, and the tensile storage modulus E' and tensile loss modulus E" of the test piece were measured in the temperature range of -30 to 280°C under conditions of a frequency of 1 Hz, a heating rate of 10°C/min, and a chuck distance of 22.5 mm. In addition, Tan δ (E"/E') based on these elastic moduli was measured. Furthermore, the temperature at which Tan δ reached its peak value was read.

(Elongation at break)
A test piece (width 10 mm x length 40 mm) was cut out from the die bond sheet. A tensile test was performed using a tensile tester (product name "Autograph AGS-50NX", manufactured by Shimadzu Corporation) to measure the breaking elongation of the test piece stretched at a predetermined tensile speed. The initial chuck distance was 10 mm, the temperature condition was 0°C, and the tensile speed was 300 mm/min. The measurement results are shown in Table 1.

The composition and physical properties of the die bond sheets in each example and comparative example are shown in Table 1.

The performance of the die bond sheet (dicing die bond film) manufactured as described above was evaluated as follows.

(Embedding ability of die bond sheet into recesses on the surface of adherend)
Using a die bonder (manufactured by Shinkawa Co., Ltd., product name "Die Bonder SPA-300"), a 10 mm x 10 mm mirror chip with a die bond sheet was bonded to a BGA substrate having a surface with 10 μm irregularities under the following conditions: stage temperature 140° C., die bond load 0.2 MPa, and die bond time 2 seconds.
The voids between the die bond sheet and the substrate (adherend) were observed using an ultrasonic imaging device (manufactured by Hitachi Finetech Co., Ltd., "FS200II"). The area occupied by the voids in the observed image was calculated using binarization software (WinRoof ver.5.6). When the area occupied by the voids was less than 10% of the surface area of the die bond film, it was evaluated as "○" (good), and when it was 10% or more, it was evaluated as "×" (bad).

(Warpage of die bond sheet after heat curing treatment)
Using a die bonder (manufactured by Shinkawa Co., Ltd., product name "Die Bonder SPA-300"), 9 mirror chips with 10 mm x 10 mm die bond sheets were bonded to a BGA substrate measuring 50 mm x 50 mm and 160 μm thick, with equal spacing between adjacent chips, under the following conditions: stage temperature 140°C, die bond load 0.2 MPa, and die bond time 2 seconds.
The substrate (adherend) after heat treatment at 150°C for 1 hour was placed on a flat plate, and the longest distance the substrate (adherend) was separated from the flat plate was measured. The evaluation results were judged as very good (◎), good (◯), and poor (×).

As can be seen from the above evaluation results, the dicing die bond film equipped with the die bond sheet of the embodiment was superior to the dicing die bond film of the comparative example in terms of the embeddability of the die bond sheet during die bonding. In addition, the amount of warping of the die bond sheet due to the thermal curing treatment was suppressed.

The die bond sheet of the embodiment contains a crosslinkable acrylic polymer, and has a shear loss modulus G″ of 1 kPa or more and 20 kPa or less at 140° C. before heat curing treatment, and a tensile modulus of elasticity at 150° C. after heat curing treatment at 150° C. for 1 hour of 0.5 MPa or more and 7.0 MPa or less at 150° C.
By using the die bond sheet (dicing die bond film) of the embodiment having such physical properties in the manufacture of semiconductor devices, for example, so-called NAND type flash memories and the like can be manufactured efficiently.
Specifically, the die bond sheet used in the embodiment for embedding a semiconductor chip has a shear loss modulus G'' within a specific range, and therefore when it is adhered to an uneven surface of an adherend, it can deform appropriately to fill in the recesses and follow the uneven shape. This makes it possible to suppress the occurrence of a gap between the adherend and the die bond sheet.
In addition, a thin semiconductor chip having an electronic circuit formed on one surface may be deformed (warped, etc.) due to internal stress accompanying the hardening treatment of the die bond sheet. In contrast, the die bond sheet of the embodiment has a tensile modulus within a specific range after the thermal hardening treatment, so that such deformation of the semiconductor chip can be suppressed.

The thermosetting resin sheet (die bond sheet) and dicing die bond film of the present invention are suitable for use, for example, as auxiliary tools when manufacturing semiconductor devices.

1: Dicing die bond film,
10: Thermosetting resin sheet (die bond sheet),
20: dicing tape,
21: Base material layer, 22: Adhesive layer.

Claims (11)

In a method for manufacturing a semiconductor device, a thermosetting resin sheet is used as a die bond sheet for bonding a chip obtained by cutting a wafer having a circuit surface thereon to an adherend by disposing the chip between the adherend and the chip,
The composition includes a crosslinkable acrylic polymer having a crosslinkable group in the molecule that undergoes a crosslinking reaction by a heat curing treatment,
A thermosetting resin sheet having a shear loss modulus G" of 1 kPa or more and 20 kPa or less at 140°C before heat curing treatment, and a tensile modulus of elasticity of 0.5 MPa or more and 7.0 MPa or less at 150°C after heat curing treatment at 150°C for 1 hour. The thermosetting resin sheet according to claim 1, wherein the content ratio of the crosslinkable acrylic polymer per 100 parts by mass of the organic component contained in the die bond sheet is 50 parts by mass or more and 100 parts by mass or less. The thermosetting resin sheet according to claim 1 or 2, in which the glass transition point Tg after heat curing treatment at 150°C for 1 hour is 20°C or more and 100°C or less, and the Tan δ at the glass transition point Tg is 0.7 or more and 1.5 or less. the crosslinkable group comprises an epoxy group;
the crosslinkable acrylic polymer has a structural unit of the glycidyl (meth)acrylate having an epoxy group in the molecule,
The thermosetting resin sheet according to claim 1 , wherein the content of the structural unit in the crosslinkable acrylic polymer is 5% by mass or more and 50% by mass or less. The content of silica filler as an inorganic filler is 40 mass% or less,
The thermosetting resin sheet according to claim 1 , wherein the silica filler has a specific surface area of 35 m ² /g or more and 400 ^{m 2} /g or less. a phenolic resin that undergoes a crosslinking reaction with the crosslinkable group by the thermal curing treatment,
The thermosetting resin sheet according to claim 1 , wherein the phenolic resin has a hydroxyl equivalent of 160 or more. The thermosetting resin sheet according to any one of claims 1 to 6, comprising one or more types of the crosslinkable acrylic polymers, at least one of which has a mass average molecular weight of 10,000 or more and 400,000 or less. The thermosetting resin sheet according to any one of claims 1 to 7, which is used by being bonded to a dicing tape. The thermosetting resin sheet according to any one of claims 1 to 8, having a breaking elongation of 50% or less at 0°C. The thermosetting resin sheet according to any one of claims 1 to 9, which is used in a SDBG (Stealth Dicing Before Grinding) process or a DBG (Dicing Before Grinding) process for manufacturing semiconductor chips by cleaving a semiconductor wafer. A dicing die bond film comprising a die bond sheet made of the thermosetting resin sheet according to any one of claims 1 to 10 and a dicing tape attached to the die bond sheet.