Dicing die-bonding film and method for manufacturing semiconductor device

Abstract

To provide a dicing die bond film or the like capable of maintaining a separation distance (kerf) between adjacent semiconductor chips for a long period of time and exhibiting good pickup properties.SOLUTION: The dicing die-bonding film includes a dicing tape having a base layer and a pressure-sensitive adhesive layer superposed on one surface of the base layer, and a die-bonding sheet superposed on the pressure-sensitive adhesive layer, wherein the dicing tape has a stress relaxation ratio of 65% or more when stretched by 5% and held for 3 minutes, and the pressure-sensitive adhesive layer has an adhesive strength of 0. 30N / 20mm or less with respect to the die-bonding sheet.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a dicing die bond film used when manufacturing, for example, a semiconductor device, and a method for manufacturing a semiconductor device using the dicing die bond film. [Background technology]

[0002] Conventionally, dicing die bond films used in the manufacture of semiconductor devices and the like have been known. This type of dicing die bond film includes, for example, a dicing tape and a die bond sheet laminated on the dicing tape and adhered to a semiconductor wafer. The dicing tape has a base layer and a pressure-sensitive 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.

[0003] A method for manufacturing a semiconductor device generally includes a front-end process in which a circuit surface is formed on one side of a disk-shaped bare wafer using highly integrated electronic circuits, and a back-end process in which semiconductor chips are cut out from the semiconductor wafer on which the circuit surface has been formed and assembled.

[0004] For example, the post-processing includes a stealth dicing process in which a fragile portion is formed in the semiconductor wafer using a laser beam to split the semiconductor wafer into small semiconductor chips (dies), a mounting process in which the surface of the semiconductor wafer opposite the circuit surface is attached to a die bond sheet and the semiconductor wafer is fixed to the dicing tape via the die bond sheet, an expanding process in which the dicing tape is stretched in the radial direction of the semiconductor wafer to split the semiconductor wafer with the fragile portion formed together with the die bond sheet and widen the gap between adjacent semiconductor chips (dies), a pick-up process in which the die bond sheet is peeled off from the adhesive layer to remove the semiconductor chip with the die bond sheet attached, a die bonding process in which the semiconductor chip 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. Note that instead of performing the stealth dicing process and the splitting in the expanding process, the semiconductor wafer after the mounting process may be cut with a dicing blade to obtain multiple semiconductor chips. A semiconductor device is manufactured through, for example, these steps.

[0005] In the above-described method of manufacturing a semiconductor device, various problems may arise, such as the inability to properly pick up the semiconductor chip in the above-described pick-up step.

[0006] In response to this, a dicing tape (workpiece processing sheet) is known in which the specific physical properties of the base layer of the dicing tape are designed to fall within a predetermined numerical range in order to properly pick up semiconductor chips in the pick-up process (for example, Patent Document 1). In the dicing tape described in Patent Document 1, the base layer has a resin layer formed from a resin composition containing a polyolefin resin, and the stress relaxation rate of the base layer after 10% stretching for 5 minutes is 35% or more. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2021-153098 Summary of the Invention [Problem to be solved by the invention]

[0008] Incidentally, when performing the pick-up process after the expanding process, a manufacturing method may be adopted in which, instead of picking up all of the obtained many semiconductor chips in order, only a portion of the many semiconductor chips is picked up, and then the remaining semiconductor chips on the dicing die bond film are stored for a long period of time (for example, several days). When such a manufacturing method is adopted, in the dicing die bond film provided with the dicing tape described in Patent Document 1, the dicing tape stretched in the expanding process tends to shrink and return to its original shape, so that the separation distance (kerf) between adjacent semiconductor chips becomes smaller over time, and the separation distance (kerf) cannot be sufficiently maintained.

[0009] Therefore, there is a demand for a dicing die bond film that can exhibit good pick-up properties and can maintain the separation distance (kerf) between adjacent semiconductor chips for a long period of time.

[0010] Therefore, an object of the present invention is to provide a dicing die bond film that can exhibit good pick-up properties and can maintain the separation distance (kerf) between adjacent semiconductor chips for a long period of time. Another object of the present invention is to provide a method for manufacturing a semiconductor device using the above dicing die bond film. [Means for solving the problem]

[0011] In order to solve the above problems, the dicing die bond film according to the present invention has the following features: a dicing tape having a base layer and a pressure-sensitive adhesive layer overlying one surface of the base layer; a die bond sheet overlying the pressure-sensitive adhesive layer, the dicing tape has a stress relaxation rate of 65% or more when elongated by 5% and held for 3 minutes; The adhesive layer has an adhesive strength of 0.30 N / 20 mm or less to the die-bonding sheet.

[0012] The manufacturing method of a semiconductor device according to the present invention is a manufacturing method of a semiconductor device, which uses the above-mentioned dicing die bond film to obtain a plurality of semiconductor chips from a semiconductor wafer, and manufactures a semiconductor device having at least one of the semiconductor chips, a mounting step of fixing the semiconductor wafer on the die bond sheet; an expanding step of cleaving the semiconductor wafer together with the die bond sheet on the adhesive layer by stretching the dicing tape to obtain the plurality of semiconductor chips from the semiconductor wafer; a pick-up step of peeling off each small piece of the die bond sheet attached to each of the plurality of semiconductor chips from the adhesive layer to pick up the plurality of semiconductor chips one by one; One day or more is allowed to pass from when the dicing tape is stretched until all of the semiconductor chips are picked up. [Effects of the Invention]

[0013] The dicing die bond film according to the present invention can exhibit good pickup properties and can maintain the separation distance (kerf) between adjacent semiconductor chips for a long period of time. According to the semiconductor device manufacturing method of the present invention, after the dicing tape is stretched in the expanding process, the separation distance (kerf) between adjacent semiconductor chips can be maintained for a long period of time, and good pickup properties can be achieved. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 2 is a cross-sectional view of the dicing die bond film of the present embodiment cut in the thickness direction. [Figure 2A]FIG. 2 is a cross-sectional view of an example of a base layer of a dicing tape in the dicing die bond film of the present embodiment, cut in the thickness direction. [Figure 2B] FIG. 10 is a cross-sectional view of another example of the base material layer of the dicing tape in the dicing die bond film of the present embodiment, cut in the thickness direction. [Figure 3A] 1A and 1B are cross-sectional views schematically illustrating a stealth dicing step in a method for manufacturing a semiconductor device. [Figure 3B] 1A and 1B are cross-sectional views schematically illustrating a stealth dicing step in a method for manufacturing a semiconductor device. [Figure 3C] 1A and 1B are cross-sectional views schematically illustrating a stealth dicing step in a method for manufacturing a semiconductor device. [Figure 3D] 1A to 1C are cross-sectional views schematically illustrating a back grinding step in the method for manufacturing a semiconductor device. [Figure 4A] 1A to 1C are cross-sectional views schematically illustrating a mounting step in a method for manufacturing a semiconductor device. [Figure 4B] 1A to 1C are cross-sectional views schematically illustrating a mounting step in a method for manufacturing a semiconductor device. [Figure 5A] 10A and 10B are cross-sectional views schematically illustrating an expanding step at a low temperature in the method for manufacturing a semiconductor device. [Figure 5B] 10A and 10B are cross-sectional views schematically illustrating an expanding step at a low temperature in the method for manufacturing a semiconductor device. [Figure 5C] 10A and 10B are cross-sectional views schematically illustrating an expanding step at a low temperature in the method for manufacturing a semiconductor device. [Figure 6A] 1A to 1C are cross-sectional views schematically illustrating an expanding step at room temperature in a method for manufacturing a semiconductor device. [Figure 6B] 1A to 1C are cross-sectional views schematically illustrating an expanding step at room temperature in a method for manufacturing a semiconductor device. [Figure 7] 1A to 1C are cross-sectional views schematically illustrating a pickup step in a method for manufacturing a semiconductor device. [Figure 8] 5A and 5B are cross-sectional views schematically illustrating a state after a die bonding step and a wire bonding step in the method for manufacturing a semiconductor device. [Figure 9] 5A to 5C are cross-sectional views schematically illustrating a sealing step in the method for manufacturing a semiconductor device. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, one embodiment of the dicing die bond film according to the present invention will be described with reference to the drawings.

[0016] As shown in FIG. 1, the dicing die bond film 1 of this embodiment includes a dicing tape 20 and a die bond sheet 10 laminated on an adhesive layer 22 (described later) of the dicing tape 20 and adhered to a semiconductor wafer. 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 product.

[0017] In the dicing die bond film 1 of this embodiment, when used, the pressure-sensitive adhesive layer 22 is cured by irradiation with active energy rays (e.g., ultraviolet rays). More specifically, in a state in which the die bond sheet 10 having a semiconductor wafer bonded to one surface and the pressure-sensitive adhesive layer 22 attached to the other surface of the die bond sheet 10 are laminated together, ultraviolet rays or the like are irradiated onto at least the pressure-sensitive 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 pressure-sensitive adhesive layer 22 after passing through the base layer 21. The pressure-sensitive 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, and therefore, after irradiation, the die bond sheet 10 (with the semiconductor chip adhered thereto) can be relatively easily peeled off from the adhesive layer 22. In the manufacture of a semiconductor device, the die bond sheet 10 is adhered to an adherend such as a circuit board or a semiconductor chip.

[0018] The adhesive layer 22 has an adhesive strength of 0.30 N / 20 mm or less to the die bond sheet 10. Such adhesive strength is, for example, the adhesive strength when picking up each semiconductor chip in the pick-up process described in detail later. Because the adhesive strength is 0.30 N / 20 mm or less, good pick-up properties can be exhibited in the pick-up process, as described in detail later. In addition, when the adhesive layer 22 is configured to be cured by irradiation with active energy rays, the above adhesive strength is increased by irradiation with a high-pressure mercury lamp (60 mW / cm 2 ) to the adhesive layer 22, a strength of 150 J / cm 2 This refers to the adhesive strength after exposure to ultraviolet light.

[0019] The adhesive strength is preferably 0.27 N / 20 mm or less, more preferably 0.25 N / 20 mm or less. By having the adhesive strength of 0.27 N / 20 mm or less, better pickup properties can be exhibited. The adhesive strength may be, for example, 0.05 N / 20 mm or more.

[0020] The adhesive strength can be increased by, for example, decreasing the content of a crosslinking agent (for example, an isocyanate compound described later) that can be contained in the adhesive layer 22. On the other hand, the adhesive strength can be decreased by increasing the content of a crosslinking agent (for example, an isocyanate compound described later) that can be contained in the adhesive layer 22.

[0021] The adhesive strength is represented by the peel force between the adhesive layer 22 of the dicing tape 20 and the die bond sheet 10. The method for measuring such peel force is as follows. A backing tape is attached to the die bond sheet of the dicing die bond film, and a test piece measuring 50 mm wide x 120 mm long is cut out from the dicing die bond film with the backing tape attached.Using the cut out test piece, a T-type peel test (90° peel test) is carried out using a tensile tester under the test conditions of temperature: 23°C, peel speed: 300 mm / min, and the peel force (N / 20 mm) is measured.

[0022] <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 this embodiment is stretched on an annular frame having an inner diameter slightly larger than that of the silicon wafer to be cut, and then cut for use.

[0023] The dicing tape 20 includes a base layer 21 and an adhesive layer 22 superposed on the base layer 21. The adhesive layer 22 of the dicing tape 20 is, for example, a pressure-sensitive adhesive layer.

[0024] The dicing tape 20 has a stress relaxation rate of 65% or more when stretched by 5% and held for 3 minutes. Because the dicing tape 20 has a stress relaxation rate of 65% or more as described above, the dicing tape 20 can maintain the separation distance (kerf) between adjacent semiconductor chips for a relatively long period of time after the expanding step described in detail below.

[0025] When the dicing tape 20 is stretched by 5% and held for 3 minutes, it preferably has a stress relaxation rate of 70% or more, more preferably 75% or more, and even more preferably 80% or more. A larger stress relaxation rate allows the separation distance (kerf) between adjacent semiconductor chips to be more adequately maintained for a relatively long period of time. The stress relaxation rate of the dicing tape 20 may be 95% or less.

[0026] The stress relaxation rate can be increased by, for example, increasing the content of a material with high stress relaxation properties, such as an α-olefin copolymer or polyurethane resin, that can be contained in the base layer 21. More specifically, for example, when the base layer 21 of the dicing tape 20 has a three-layer structure as described below, the stress relaxation rate can be increased by increasing the relative thickness of the inner layer (intermediate layer) containing an α-olefin copolymer or polyurethane resin. On the other hand, the stress relaxation rate can be decreased by decreasing the thickness of such an inner layer.

[0027] The stress relaxation rate is measured as follows. Dicing tape is cut to prepare strip-shaped test pieces measuring 150 mm in length and 10 mm in width. The strip-shaped test pieces are set in a tensile tester, and measurements are performed in an atmosphere of 23°C and 50% RH. Specifically, the strip-shaped test pieces are pulled under test conditions of an initial chuck distance of 300 mm and a tensile speed of 600 mm / min, and are stretched (elongated) to an elongation of 5% and then stopped. The stress value is then measured within a range of 180 seconds after stopping. The stress value immediately after 5% stretching (stress value at the end of stretching) is designated as A, and the stress value 180 seconds after the end of stretching is designated as B, and the stress relaxation rate is calculated using the following formula. Stress relaxation rate (%) = [(AB) / A] x 100

[0028] The dicing tape 20 preferably has a tensile storage modulus of 60 MPa or more, more preferably 80 MPa or more, and even more preferably 200 MPa or more at 25°C. By increasing the tensile storage modulus of the dicing tape 20, slack in the dicing tape 20 can be further suppressed even after a relatively long period of time has passed since the dicing tape 20 was stretched in the expanding step described in detail below. The tensile storage modulus may be 1,000 MPa or less.

[0029] The tensile storage modulus can be increased by, for example, using a material having a higher tensile storage modulus as the material constituting the base layer 21. More specifically, for example, when the base layer 21 of the dicing tape 20 has a three-layer structure as described below, the tensile storage modulus can be increased by using materials having a higher tensile storage modulus as the materials constituting the two outer layers (outermost layers). On the other hand, the tensile storage modulus can be decreased by using materials having a lower tensile storage modulus as the materials constituting the two outer layers.

[0030] The tensile storage modulus is measured as follows. Dynamic viscoelasticity measurement is performed using a dynamic viscoelasticity measuring device to determine the tensile storage modulus at 25°C. Specifically, a test piece measuring 10 mm wide x 40 mm long is cut out from a dicing tape with a thickness of 100 μm, and measurement is performed under the following conditions to determine the storage modulus at 25°C. Initial chuck distance: 22.5mm Measurement mode: Tensile mode Measurement environment: Nitrogen atmosphere Measurement temperature range: -40℃ to 280℃ ·Measurement frequency: 10Hz Dynamic strain: 0.005% Heating rate: 10℃ / min

[0031] [Dicing tape base layer] In this embodiment, the base layer 21 superposed on one side of the pressure-sensitive adhesive layer 22 has, for example, a single-layer structure or a laminated structure (for example, a three-layer structure), as shown in FIGS. 2A and 2B, respectively.

[0032] Each layer of the base material layer 21 is, for example, a rubber sheet or a resin film. The base material layer 21 preferably contains at least one of an α-olefin copolymer and a polyurethane resin, more preferably contains at least an α-olefin copolymer, and even more preferably is made of an α-olefin copolymer film. This enables the dicing tape 20 to more adequately maintain the separation distance (kerf) between adjacent semiconductor chips for a long period of time.

[0033] 2B, the base material layer 21 may be configured as three layers, with a first base material layer 21a, a second base material layer 21b, and a third base material layer 21c stacked one on top of the other. The three-layer base material layer 21 preferably has a second base material layer 21b containing an α-olefin copolymer or a polyurethane resin, and a first base material layer 21a and a third base material layer 21c overlapping both sides of the second base material layer 21b and containing a resin other than an α-olefin copolymer or a polyurethane resin. The base material layer 21 having such a three-layer laminate structure is formed, for example, by producing each layer by co-extrusion molding and integrating the three layers.

[0034] In the three-layer substrate layer 21, the first substrate layer 21a and the third substrate layer 21c, which are disposed on both sides, preferably contain polyolefin resin or ethylene-vinyl acetate copolymer resin (EVA), and the second substrate layer 21b, which is disposed between the first substrate layer 21a and the third substrate layer 21c, preferably contains α-olefin copolymer or polyurethane resin. This allows the substrate layer 21 to exhibit not only the relatively high stress relaxation characteristic of α-olefin copolymer or polyurethane resin, but also the relatively high moldability characteristic of polyolefin resin or ethylene-vinyl acetate copolymer resin (EVA). Therefore, for example, after the dicing tape 20 is stretched in the expanding process, the separation distance (kerf) between adjacent semiconductor chips can be sufficiently maintained for a long period of time. In the substrate layer 21, for example, the layer farthest from the adhesive layer 22 is the first substrate layer 21a, and the layer overlapping the adhesive layer 22 is the third substrate layer 21c. The second base material layer 21b is disposed between the first base material layer 21a and the third base material layer 21c.

[0035] In the three-layer base layer 21, the ratio of the thickness of the inner layer (middle layer) to the total thickness of the outer layers (outermost layers) (thickness of the second base layer 21b / total thickness of the first base layer 21a and the third base layer 21c) is preferably 1 or more, and more preferably 2 or more. This thickness ratio is preferably 10 or less, and more preferably 5 or less. The thicknesses of the first base layer 21a and the third base layer 21c may be approximately the same. For example, the ratio of the thickness of the first base layer 21a to the thickness of the third base layer 21c may be 0.9 or more and 1.1 or less. The first base material layer 21a and the third base material layer 21c may have the same thickness and material.

[0036] The thickness (total thickness) of the base layer 21 is preferably 80 μm or more and 150 μm or less. This value is the average of measurements taken at least three randomly selected locations. Hereinafter, the thickness of the pressure-sensitive adhesive layer 22 is also the average of measurements taken in the same manner. When the thickness of the base layer 21 is 80 μm or more, stress can be applied more uniformly to the entire base layer 21, and the semiconductor wafer can be more effectively cleaved in the expanding step.

[0037] In the three-layer base material layer 21, the first base material layer 21a and the third base material layer 21c preferably each independently have a thickness of 1 μm or more and 15 μm or less, and the second base material layer 21b has a thickness of 70 μm or more and 120 μm or less, which has the advantage that the physical properties (characteristics) of each layer in the base material layer 21 are more suitably reflected in the base material layer 21.

[0038] By having the base layer 21 have a laminated structure (e.g., a three-layer structure) in which multiple layers are stacked, it becomes possible to stack a layer with a higher elastic modulus and a layer with a lower elastic modulus. Therefore, the elastic modulus of the base layer 21 can be controlled relatively easily. For example, if the elastic modulus of the base layer 21 consisting of only one layer is relatively high, the base layer 21 may be more likely to break during the expanding process. Furthermore, for example, the stress for cleaving the semiconductor chip is transmitted from the force stretching the dicing tape 20 during the expanding process through the base layer 21 and the adhesive layer 22. However, if the elastic modulus of the base layer 21 consisting of only one layer is relatively low, the stress may be less likely to be transmitted. In this way, since the base material layer 21 is composed of multiple layers, the physical properties (characteristics) of each layer can be brought out. Therefore, a base material layer composed of multiple layers is more likely to exhibit desired characteristics than a single-layer base material layer.

[0039] The second base layer 21b preferably contains α-olefin copolymer or polyurethane resin in a total amount of 50% by mass or more, and more preferably 80% by mass or more, which enables the dicing tape 20 to more satisfactorily maintain the separation distance (kerf) between adjacent semiconductor chips for a long period of time.

[0040] The α-olefin copolymer that can be contained in the second base layer 21b has at least one of ethylene units and propylene units in the molecule, and other monomer units such as 4-methyl-1-pentene or 1-butene.

[0041] The polyurethane resin that can be contained in the second base layer 21b is a general term for a urethane reaction product of at least a polyisocyanate compound having multiple (two or more) isocyanate groups in the molecule and a polyol compound having multiple (two or more) hydroxy groups in the molecule. As the polyurethane resin, a general commercially available product can be used.

[0042] The first base layer 21a preferably contains a polyolefin resin or an ethylene-vinyl acetate copolymer resin in a total amount of 50% by mass or more, and more preferably 80% by mass or more, which allows the dicing tape 20 to have more sufficient moldability.

[0043] The polyolefin resin that can be contained in the first base layer 21a is, for example, a resin having at least one of an ethylene unit and a propylene unit in the molecule. Examples of such resins include polyolefin homopolymers such as low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene (PP), and ethylene-propylene copolymers; ionomer resins; and copolymers of ethylene and a non-olefin, such as ethylene-(meth)acrylic acid ester (random or alternating) copolymers. Examples of the polyolefin homopolymer include a propylene-based elastomer resin (containing an ethylene repeating unit and an isotactic propylene repeating unit in the molecule) and a metallocene polypropylene resin (polypropylene polymerized with a metallocene catalyst). By using the above-mentioned propylene-based elastomer resin as the polyolefin homopolymer, the shelf life of the base layer 21 (resistance to blocking after deterioration over time) can be improved.

[0044] The ethylene-vinyl acetate copolymer resin (EVA) that can be contained in the first base layer 21a may contain 5% to 35% by mass of vinyl acetate structural units. The structural units are structures derived from each monomer (ethylene, vinyl acetate) after polymerization of the monomers when polymerizing the ethylene-vinyl acetate copolymer.

[0045] When the base material layer 21 has a three-layer structure, the third base material layer 21c can be made of the same material as the first base material layer 21a. When the base material layer 21 has a single-layer structure, the base material layer 21 can be made of the same material as the second base material layer 21b.

[0046] If necessary, each layer of the base material layer 21 may further contain, for example, polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), etc.; polyacrylate; polyvinyl chloride (PVC); polyurethane; polycarbonate; polyphenylene sulfide (PPS); polyamides such as aliphatic polyamides and wholly aromatic polyamides (aramids); polyether ether ketone (PEEK); polyimide; polyetherimide; polyvinylidene chloride; ABS (acrylonitrile-butadiene-styrene copolymer); cellulose or a cellulose derivative; silicone-containing polymers; fluorine-containing polymers, etc.

[0047] When each layer of the base material layer 21 has a resin film, the resin film may be subjected to a stretching treatment or the like to control the deformability such as elongation.

[0048] Each layer of the base material layer 21 may further contain an antistatic agent. The antistatic agent can prevent static electricity from building up in the base material layer 21. This can adequately prevent electrostatic breakdown of the electronic circuits in the semiconductor chip due to static electricity discharge. Furthermore, preventing static electricity can adequately prevent foreign matter such as dust from adhering to the base material layer 21.

[0049] 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 to impart releasability.

[0050] On the other hand, the surface of the base layer 21 in contact with the pressure-sensitive adhesive layer 22 may be subjected to a surface treatment to enhance adhesion to the pressure-sensitive adhesive layer 22. Examples of surface treatments that can be used include oxidation treatments using chemical or physical methods such as chromic acid 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.

[0051] [Adhesive layer of dicing tape] In this embodiment, the pressure-sensitive adhesive layer 22 contains, for example, an acrylic copolymer, an isocyanate compound, and a polymerization initiator. The pressure-sensitive adhesive layer 22 may have a thickness of 40 μm or less. The thickness of the pressure-sensitive adhesive layer 22 is preferably 10 μm or less, more preferably 7 μm or less, and even more preferably 5 μm or less. The pressure-sensitive adhesive layer 22 may have a thickness of 1 μm or more. 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.

[0052] In this embodiment, the pressure-sensitive adhesive layer 22 contains at least an acrylic copolymer having, as monomer units in the molecule, an alkyl (meth)acrylate unit and a crosslinkable group-containing (meth)acrylate unit. The term "unit" refers to a structure derived from each monomer after polymerization of the monomer (for example, 2-ethylhexyl acrylate, hydroxyethyl acrylate, etc.) when polymerizing the acrylic copolymer. The same applies hereinafter.

[0053] In this specification, 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."

[0054] The acrylic copolymer has at least an alkyl (meth)acrylate unit and a crosslinkable group-containing (meth)acrylate unit as monomer units in the molecule. The monomer units are units that constitute the main chain of the acrylic copolymer. In other words, the monomer units are derived from the monomers used to polymerize the acrylic copolymer. Each side chain in the acrylic copolymer is contained in each monomer unit that constitutes the main chain.

[0055] The alkyl (meth)acrylate unit is derived from an alkyl (meth)acrylate monomer. In other words, the molecular structure obtained after the alkyl (meth)acrylate monomer is polymerized is an alkyl (meth)acrylate unit. The term "alkyl" refers to the hydrocarbon moiety ester-bonded to (meth)acrylic acid.

[0056] The alkyl portion (hydrocarbon) in the alkyl (meth)acrylate unit may be a saturated hydrocarbon or an unsaturated hydrocarbon. The alkyl portion (hydrocarbon) in the alkyl (meth)acrylate unit may be a straight-chain hydrocarbon, a branched-chain hydrocarbon, or may contain a cyclic structure. The alkyl portion (hydrocarbon) in the alkyl(meth)acrylate unit may have 6 or more and 22 or less carbon atoms.

[0057] The acrylic copolymer more preferably contains, as the alkyl(meth)acrylate unit, a saturated alkyl(meth)acrylate unit in which the alkyl moiety is a saturated hydrocarbon having 6 to 22 carbon atoms.

[0058] The acrylic copolymer preferably has the highest molar ratio of alkyl(meth)acrylate units having 6 or more carbon atoms in the alkyl moiety among all monomer units in the molecule. For example, alkyl(meth)acrylate units having 6 or more carbon atoms in the alkyl moiety (preferably 8 or more carbon atoms) may account for 50% to 90% of all monomer units in molar ratio.

[0059] The saturated alkyl (meth)acrylate unit having 6 or more carbon atoms in the alkyl portion preferably does not contain any of a benzene ring, an ether bond (-CH2-O-CH2-), an -OH group, a -COOH group, or other polar groups in the molecule. In the saturated alkyl (meth)acrylate unit having 6 or more carbon atoms in the alkyl portion, the alkyl portion does not contain atoms other than C and H and may be a saturated linear hydrocarbon or a saturated branched hydrocarbon composed of 6 to 10 carbon atoms.

[0060] The acrylic copolymer preferably contains, as the alkyl (meth)acrylate unit, a saturated branched alkyl (meth)acrylate unit having an alkyl moiety with 6 to 10 carbon atoms.

[0061] The structure of the alkyl portion (hydrocarbon portion) of the saturated branched alkyl (meth)acrylate unit may be a saturated branched alkyl structure, and may be an iso structure, a sec structure, a neo structure, or a tert structure. Specific examples of saturated branched alkyl (meth)acrylate units include isohexyl (meth)acrylate, isoheptyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, isodecyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate units. Among these, 2-ethylhexyl (meth)acrylate units are preferred.

[0062] The structure of the alkyl portion (hydrocarbon portion) of the saturated linear alkyl (meth)acrylate unit may be any structure as long as it is a saturated linear alkyl structure. Specific examples of saturated linear alkyl (meth)acrylate units include 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, and behenyl (meth)acrylate units.

[0063] The acrylic copolymer may contain one type of alkyl (meth)acrylate unit alone, or may contain two or more types of alkyl (meth)acrylate units.

[0064] The crosslinkable group-containing (meth)acrylate unit has a hydroxy group capable of forming a urethane bond through a urethanization reaction or a polymerizable group capable of polymerizing through a radical reaction. More specifically, the crosslinkable group-containing (meth)acrylate unit has either an unreacted hydroxy group or a radically polymerizable carbon-carbon double bond as a polymerizable group. In other words, some of the crosslinkable group-containing (meth)acrylate units have unreacted hydroxy groups, and the other part (all others) have no hydroxy groups but have radically polymerizable carbon-carbon double bonds.

[0065] The acrylic copolymer has, as the crosslinkable group-containing (meth)acrylate unit, a hydroxy group-containing (meth)acrylate unit in which a hydroxy group is bonded to an alkyl moiety having four or less carbon atoms. When the pressure-sensitive adhesive layer 22 contains an isocyanate compound, the isocyanate group of the isocyanate compound and the hydroxy group of the hydroxy group-containing (meth)acrylate unit can easily react with each other. By allowing the acrylic copolymer having a hydroxyl group-containing (meth)acrylate unit and the 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 copolymer to be sufficiently gelled. As a result, the pressure-sensitive adhesive layer 22 can maintain its shape while exhibiting adhesive performance.

[0066] The hydroxy group-containing (meth)acrylate unit is preferably a hydroxy group-containing C2-C4 alkyl (meth)acrylate unit in which an OH group is bonded to an alkyl moiety having from 2 to 4 carbon atoms. The term "C2 to 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 hydroxy 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 from 2 to 4 carbon atoms. The same applies hereinafter in this specification. The hydrocarbon portion of the C2-C4 alkyl is usually a saturated hydrocarbon. For example, the hydrocarbon portion of the C2-C4 alkyl is a linear saturated hydrocarbon or a branched saturated hydrocarbon. It is preferable that the hydrocarbon portion of the C2-C4 alkyl does not contain a polar group containing oxygen (O), nitrogen (N), or the like.

[0067] Examples of the hydroxy group-containing C2-C4 alkyl(meth)acrylate unit include hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate, hydroxy n-butyl(meth)acrylate, and hydroxy isobutyl(meth)acrylate units. The hydroxy group (-OH group) may be bonded to a terminal carbon (C) of the hydrocarbon moiety, or to a carbon (C) other than the terminal of the hydrocarbon moiety.

[0068] The acrylic copolymer contains, as the crosslinkable group-containing (meth)acrylate unit, a polymerizable (meth)acrylate unit having a radically polymerizable carbon-carbon double bond (polymerizable unsaturated double bond) in the side chain.

[0069] Specifically, the polymerizable (meth)acrylate unit has a molecular structure in which an isocyanate group of an isocyanate group-containing (meth)acrylic monomer is urethane-bonded to a hydroxy group in the above-mentioned hydroxy group-containing (meth)acrylate unit.

[0070] Since the acrylic copolymer contains a radically polymerizable carbon-carbon double bond in the crosslinkable group-containing (meth)acrylate unit, the pressure-sensitive adhesive layer 22 can be cured by irradiation with active energy rays (ultraviolet rays, etc.) before the above-mentioned pick-up step. For example, irradiation with active energy rays such as ultraviolet rays generates radicals from the photopolymerization initiator, and the acrylic copolymer can be crosslinked by the action of these radicals. This makes it possible to reduce the adhesive strength of the pressure-sensitive adhesive layer 22 before irradiation after irradiation. This also makes it possible to easily peel the die bond sheet 10 from the pressure-sensitive adhesive layer 22. The active energy rays include ultraviolet rays, radioactive rays, and electron beams.

[0071] The polymerizable (meth)acrylate unit can be prepared by a urethane reaction after the polymerization reaction of an acrylic copolymer. 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 hydroxyl group-containing (meth)acrylate unit and the isocyanate group of the isocyanate group-containing polymerizable monomer can be subjected to a urethane reaction to obtain the polymerizable (meth)acrylate unit.

[0072] The isocyanate group-containing (meth)acrylic monomer preferably has one isocyanate group and one (meth)acryloyl group in the molecule, such as 2-methacryloyloxyethyl isocyanate.

[0073] In this embodiment, the acrylic copolymer may contain a monomer unit other than the above-mentioned monomer units. For example, it may contain units such as (meth)acryloylmorpholine, N-vinyl-2-pyrrolidone, or acrylonitrile. By containing (meth)acryloylmorpholine units as monomer units and changing the composition ratio of the (meth)acryloylmorpholine units in the acrylic copolymer, the glass transition temperature or polarity of the acrylic copolymer can be controlled relatively easily.

[0074] In the acrylic copolymer contained in the pressure-sensitive adhesive layer 22, the above-mentioned units (constituent units) are 1 H-NMR, 13 This can be confirmed by NMR analysis such as C-NMR, pyrolysis GC / MS analysis, infrared spectroscopy, etc. The molar ratio of the above units in the acrylic copolymer is usually calculated from the blending amounts (charge amounts) when the acrylic copolymer is polymerized.

[0075] Of the total monomer units (100 parts by mole) in the acrylic copolymer, it is preferable that the proportion of crosslinkable group-containing (meth)acrylate units is 15 to 60 parts by mole, and that 50 to 95% (in terms of moles) of the crosslinkable group-containing (meth)acrylate units form urethane bonds as described above. In other words, when the total monomer units are taken as 100 parts by mole, the acrylic copolymer preferably contains 15 to 60 parts by mole of crosslinkable group-containing (meth)acrylate units, and that 50 to 95% of the crosslinkable group-containing (meth)acrylate units are polymerizable (meth)acrylate units having a radical polymerizable carbon-carbon double bond. This allows the adhesive strength between the die bond sheet 10 and the pressure-sensitive adhesive layer 22 before curing to be maintained, while improving the peelability between the die bond sheet 10 and the pressure-sensitive adhesive layer 22 after curing.

[0076] The acrylic copolymer preferably contains 10 to 50 parts by mole of polymerizable (meth)acrylate units when the total monomer units are taken as 100 parts by mole. This allows the adhesive strength between the die bond sheet 10 and the pressure-sensitive adhesive layer 22 before curing to be maintained, while improving the peelability between the die bond sheet 10 and the pressure-sensitive adhesive layer 22 after curing.

[0077] In this embodiment, the isocyanate compound that may be further contained in the pressure-sensitive adhesive layer 22 of the dicing tape 20 has multiple isocyanate groups in its molecule. The isocyanate compound having multiple isocyanate groups in its molecule can promote a crosslinking reaction between acrylic copolymers in the pressure-sensitive adhesive layer 22. Specifically, one isocyanate group of the isocyanate compound can be reacted with a hydroxy group of an acrylic copolymer, and the other isocyanate group can be reacted with a hydroxy group of another acrylic copolymer, thereby promoting a crosslinking reaction via the isocyanate compound. In other words, the isocyanate compound can serve as a type of crosslinking agent. The isocyanate compound may be a compound synthesized through a urethane reaction or the like.

[0078] Examples of the isocyanate compound include diisocyanates such as aliphatic diisocyanates, alicyclic diisocyanates, and araliphatic diisocyanates.

[0079] Furthermore, examples of the isocyanate compound include polymerized polyisocyanates such as dimers and trimers of diisocyanates, and polymethylene polyphenylene polyisocyanates.

[0080] In addition, examples of the isocyanate compound include polyisocyanates obtained by reacting an excess amount of the above-mentioned isocyanate compound with an active hydrogen-containing compound, such as an active hydrogen-containing low molecular weight compound or an active hydrogen-containing high molecular weight compound. As the isocyanate compound, allophanated polyisocyanate, biureted polyisocyanate, etc. may also be used. The above isocyanate compounds can be used alone or in combination of two or more.

[0081] The 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 the 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 isocyanate compound is preferably one having three or more isocyanate groups in the molecule.

[0082] In this embodiment, the polymerization initiator contained in the pressure-sensitive adhesive layer 22 is a compound that can initiate a polymerization reaction by applied heat or light energy. By including a polymerization initiator in the pressure-sensitive adhesive layer 22, a cross-linking reaction between acrylic copolymers can be promoted when heat energy or light energy is applied to the pressure-sensitive adhesive layer 22. Specifically, a polymerization reaction between polymerizable groups can be initiated between acrylic copolymers having polymerizable (meth)acrylate units containing radically polymerizable carbon-carbon double bonds, thereby curing the pressure-sensitive adhesive layer 22. This reduces the adhesive strength of the pressure-sensitive adhesive layer 22, and allows the die bond sheet 10 to be easily peeled off from the cured pressure-sensitive adhesive layer 22 in the pick-up step. 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.

[0083] The pressure-sensitive 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 may be appropriately selected depending on the purpose.

[0084] <Dicing die bond film die bond sheet> As shown in FIG. 1, the die bond sheet 10 is overlaid on the adhesive layer 22 of the dicing tape 20 described above.

[0085] 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. The thickness of the die bond sheet 10 is preferably 3 μm or more, and more preferably 5 μm or more. The thickness of the die bond sheet 10 is preferably 150 μm or less, more preferably 140 μm or less, and even more preferably 40 μm or less. When the die bond sheet 10 is a laminate, the above thickness is the total thickness of the laminate. By making the thickness of the die bond sheet 10 thicker, the die bond sheet 10 can more easily fit into the recesses in the unevenness of the adherend surface when the die bond sheet 10 is adhered to the adherend (the embeddability can be improved). On the other hand, by making the thickness of the die bond sheet 10 thinner, the thickness of the package portion provided with the die bond sheet 10 in a semiconductor device or the like can be made thinner (thinner layer).

[0086] The die bond sheet 10 preferably has a tensile storage modulus of 5 MPa or more and 10,000 MPa or less at 25° C. Such a tensile storage modulus of 5 MPa or more can prevent the die bond sheet 10 from being excessively stretched when the die bond sheet 10 is cut, as will be described in detail later. On the other hand, such a tensile storage modulus of 10,000 MPa or less can make it easier to cut the die bond sheet 10.

[0087] The tensile storage modulus of the die bond sheet 10 can be increased, for example, by forming the die bond sheet 10 from a material having a higher glass transition point. On the other hand, the tensile storage modulus of the die bond sheet 10 can be decreased, for example, by forming the die bond sheet 10 from a material having a lower glass transition point.

[0088] The tensile storage modulus of the die bond sheet 10 is a value measured in the same manner as the tensile storage modulus of the dicing tape described above. Note that the measurement is performed by cutting a test piece having a width of 10 mm and a length of 40 mm from a die bond sheet having a thickness of 200 μm.

[0089] 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 multiple layers formed of the same composition are stacked is also considered a single layer. On the other hand, the die bond sheet 10 may have a multilayer structure in which layers formed of, for example, two or more different compositions are laminated. When the die bond sheet 10 has a multilayer structure, at least one layer constituting the die bond sheet 10 may contain a crosslinkable group-containing acrylic polymer described below, and may further contain a thermosetting resin as necessary.

[0090] The die bond sheet 10 contains a crosslinkable group-containing acrylic polymer having a crosslinkable group in the molecule that undergoes a crosslinking reaction by heat curing treatment. Such a crosslinkable group-containing acrylic polymer is a polymer compound in which at least (meth)acrylic acid ester monomers are polymerized.

[0091] The crosslinkable group-containing acrylic polymer generally has the crosslinkable group in a side chain. The crosslinkable group-containing acrylic polymer may have the crosslinkable group at the end of the side chain. The crosslinkable group-containing acrylic polymer may have the crosslinkable group at at least one of both ends of the main chain.

[0092] The crosslinkable group contained in the molecule of the crosslinkable group-containing acrylic polymer is not particularly limited as long as it is a functional group that undergoes a crosslinking reaction upon heat curing treatment.

[0093] Examples of the crosslinkable group include a hydroxy group and a carboxy group. These crosslinkable groups can undergo a crosslinking reaction with an epoxy group or an isocyanate group. For example, the above-mentioned crosslinkable group-containing acrylic polymer having at least one of a hydroxy group and a carboxy 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, which will be described later).

[0094] Examples of crosslinkable groups include epoxy groups and isocyanate groups. These crosslinkable groups can undergo crosslinking reactions with hydroxy groups and carboxy groups. For example, the above-mentioned crosslinkable group-containing acrylic polymer having at least one of an epoxy group and an isocyanate group in the molecule can undergo crosslinking reactions with a compound having at least one of a hydroxy group and a carboxy group in the molecule (e.g., a phenolic resin, which will be described later).

[0095] In the present embodiment, the crosslinkable group-containing acrylic polymer contained in the die bond sheet 10 preferably contains at least one of a hydroxy group and a carboxy group as a crosslinkable group, thereby allowing the die bond sheet 10 to be better adhered to the adherend.

[0096] In the above-mentioned crosslinkable group-containing acrylic polymer, the proportion of the structural units of the crosslinkable group-containing monomer may be 0.1% by mass or more and 60.0% by mass or less, 0.5% by mass or more and 40.0% by mass or less, 1.0% by mass or more and 30.0% by mass or less, or 3.0% by mass or more and 20.0% by mass or less. The structural unit is a structure derived from each monomer after polymerization of the monomer (for example, 2-ethylhexyl acrylate, hydroxyethyl acrylate, etc.) when polymerizing the crosslinkable group-containing acrylic polymer. The same applies hereinafter.

[0097] The crosslinkable group-containing acrylic polymer can be synthesized by a general polymerization method using a radical polymerization initiator, or a commercially available product can be used as the crosslinkable group-containing acrylic polymer.

[0098] The crosslinkable group-containing acrylic polymer preferably contains, among the structural units in the molecule, the structural unit of an alkyl(meth)acrylate monomer in the largest mass proportion. Examples of the alkyl(meth)acrylate monomer include C1-C18 alkyl(meth)acrylate monomers having an alkyl group (hydrocarbon group) with 1 to 18 carbon atoms. The alkyl(meth)acrylate monomer may also be, for example, a C1-C12 alkyl(meth)acrylate monomer having an alkyl group (hydrocarbon group) with 1 to 12 carbon atoms.

[0099] Examples of the alkyl(meth)acrylate monomer include saturated linear alkyl(meth)acrylate monomers and saturated branched alkyl(meth)acrylate monomers.

[0100] Examples of saturated linear alkyl (meth)acrylate monomers include methyl (meth)acrylate, 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 moiety is preferably 2 or more and 8 or less. Examples of saturated branched alkyl (meth)acrylate monomers 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.

[0101] The above-mentioned crosslinkable group-containing acrylic polymer contains a constituent unit derived from a crosslinkable group-containing monomer copolymerizable with an alkyl(meth)acrylate monomer. In this embodiment, the crosslinkable group-containing acrylic polymer is an acrylic polymer obtained by copolymerizing at least an alkyl(meth)acrylate monomer and a crosslinkable group-containing monomer. In other words, the crosslinkable group-containing acrylic polymer has a structure in which constituent units of the alkyl(meth)acrylate monomer and constituent units of the crosslinkable group-containing monomer are linked in random order.

[0102] 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- (glycidyl group-) containing (meth)acrylic monomers, isocyanate group-containing (meth)acrylic monomers, sulfonic acid group-containing (meth)acrylic monomers, phosphate group-containing (meth)acrylic monomers, acrylamide, acrylonitrile, etc. The crosslinkable group-containing monomers may have an ether group or an ester group in the molecule.

[0103] The crosslinkable group-containing 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 alkyl (meth)acrylate (particularly alkyl (meth)acrylate with an alkyl portion having 8 or less carbon atoms).

[0104] Examples of carboxy group-containing (meth)acrylic monomers include (meth)acrylic acid, mono(2-(meth)acryloyloxyethyl)succinate monomer, etc. The carboxy group may be located at the 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 monomer, hydroxypropyl (meth)acrylate monomer, hydroxybutyl (meth)acrylate monomer, etc. The hydroxy group may be located at the terminal portion of the monomer structure, or may be bonded to a hydrocarbon at a portion 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 at a portion other than the terminal portion. Examples of the isocyanate group-containing (meth)acrylic monomer include 2-methacryloyloxyethyl isocyanate, 1,1-(bisacryloyloxymethyl)ethyl isocyanate, 2-acryloyloxyethyl isocyanate, and 2-(2-methacryloyloxyethyloxy)ethyl isocyanate.

[0105] The die bond sheet 10 may contain a component other than the above-mentioned crosslinkable group-containing acrylic polymer. For example, the die bond sheet 10 may further contain at least one of a thermosetting resin and a thermoplastic resin other than the above-mentioned crosslinkable group-containing acrylic polymer.

[0106] Examples of the thermosetting resin include epoxy resin, phenol resin, amino resin, unsaturated polyester resin, polyurethane resin, silicone resin, thermosetting polyimide resin, etc. As the thermosetting resin, only one type or two or more types may be used.

[0107] Examples of the epoxy resin 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.

[0108] Phenol resins can act as curing agents for epoxy resins, and examples of phenolic resins include novolac-type phenolic resins, resol-type phenolic resins, and polyoxystyrenes such as polyparaoxystyrene. Examples of novolac type phenolic resins include phenol novolac resins, phenol aralkyl resins, cresol novolac resins, tert-butylphenol novolac resins, and nonylphenol novolac resins. The hydroxyl group equivalent [g / eq] of the phenolic resin may be, for example, 90 or more and 220 or less. As the phenolic resin, only one kind or two or more kinds may be employed.

[0109] In the present embodiment, the die bond sheet 10 may contain the above-mentioned crosslinkable group-containing acrylic polymer and thermosetting resin, which undergo a crosslinking reaction with each other.

[0110] For example, the die bond sheet 10 may contain an epoxy group-containing acrylic polymer as the crosslinkable group-containing acrylic polymer and a phenol resin as the thermosetting resin, whereby the epoxy groups of the crosslinkable group-containing acrylic polymer and the hydroxyl groups of the phenol resin undergo a crosslinking reaction to sufficiently harden the die bond sheet 10.

[0111] Examples of thermoplastic resins other than the above-mentioned crosslinkable group-containing acrylic polymer that can be contained 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, etc. As the thermoplastic resin, one kind alone or two or more kinds may be adopted.

[0112] In the die-bonding sheet 10, the content of the crosslinkable group-containing acrylic polymer is preferably 8% by mass or more and 100% by mass or less.

[0113] In the die bond sheet 10, the content ratio of the above-mentioned crosslinkable group-containing acrylic polymer relative to 100 parts by mass of organic components excluding the filler (for example, the above-mentioned crosslinkable group-containing acrylic polymer, thermosetting resin, curing catalyst, silane coupling agent, dye) is preferably 15 parts by mass or more and 100 parts by mass or less, more preferably 20 parts by mass or more and 80 parts by mass or less, and even more preferably 60 parts by mass or less. Note that by changing the content ratio of the thermosetting resin in the die bond sheet 10, the elasticity and viscosity of the die bond sheet 10 can be adjusted. On the other hand, the content of the thermosetting resin may be 50 parts by mass or more and 90 parts by mass or less per 100 parts by mass of the organic component.

[0114] The die bond sheet 10 may or may not contain a filler. By changing the amount of filler in the die bond sheet 10, it is possible to more easily adjust the elasticity and viscosity of the die bond sheet 10. Furthermore, it is possible to adjust the physical properties of the die bond sheet 10, such as electrical conductivity, thermal conductivity, and elastic modulus.

[0115] The filler may be an inorganic filler or an organic filler, with the inorganic filler being 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, and silica such as crystalline silica and amorphous silica. Examples of inorganic filler materials include simple metals such as aluminum, gold, silver, copper, and nickel, as well as alloys. Fillers such as aluminum borate whiskers, amorphous carbon black, and graphite are also acceptable. The filler may have various shapes, such as spherical, acicular, and flake-like. Only one or more of the above fillers may be used.

[0116] When the die bond sheet 10 contains a filler, the content of the filler may be 50 mass % or less of the total mass of the die bond sheet 10. The content of the filler may be, for example, 5 mass % or more.

[0117] The die bond sheet 10 may contain other components as needed, such as 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 resin. 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, only one kind or two or more kinds may be employed.

[0118] The die bond sheet 10 preferably contains the above-mentioned crosslinkable group-containing acrylic polymer, thermosetting resin, and filler, in that the elasticity and viscosity can be easily adjusted.

[0119] The dicing die bond film 1 of this embodiment may have a release liner that covers one side of the die bond sheet 10 (the side of the die bond sheet 10 that is not overlapped with the pressure-sensitive adhesive layer 22) before use. The release liner is used to protect the die bond sheet 10, and is peeled off immediately before attaching an adherend (for example, a semiconductor wafer) to the die bond sheet 10. The release liner may be, for example, a plastic film or paper whose surface has been treated with a release agent such as a silicone-based, long-chain alkyl-based, fluorine-based, or molybdenum sulfide-based release agent. The release liner can be used as a support material for supporting the die bond sheet 10. The release liner is suitably used when overlaying the die bond sheet 10 on the pressure-sensitive adhesive layer 22. In detail, the die bond sheet 10 is overlaid on the pressure-sensitive adhesive layer 22 in a state where the release liner and the die bond sheet 10 are laminated, and after overlaying, the release liner is peeled off (transferred), thereby overlaying the die bond sheet 10 on the pressure-sensitive adhesive layer 22.

[0120] Next, a method for manufacturing the dicing die bond film 1 of this embodiment will be described.

[0121] <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.

[0122] <Process for producing die bond sheet> The process of producing the die bond sheet 10 includes: 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.

[0123] In the resin composition preparation step, for example, the above-mentioned crosslinkable group-containing acrylic polymer is mixed with either an epoxy resin, a phenolic resin, a curing catalyst, or a solvent, and each resin is dissolved in the solvent to prepare a resin composition. The viscosity of the composition can be adjusted by changing the amount of solvent. Commercially available products can be used as these resins.

[0124] In the die-bonding sheet forming step, for example, the resin composition prepared as described above is applied to a release liner. The application method is not particularly limited, and for example, a general application method such as roll coating, screen coating, or gravure coating is used. Next, if necessary, the applied composition is solidified by a solvent removal treatment or a curing treatment, etc., to form the die-bonding sheet 10.

[0125] <Process for producing dicing tape> The process of producing the dicing tape includes: a synthesis step of synthesizing an acrylic copolymer; 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 copolymer, an isocyanate compound, a polymerization initiator, a solvent, and other components that are appropriately added depending on the purpose; a base material layer preparation step of preparing a base material layer 21; and a lamination step of laminating the base layer 21 and the adhesive layer 22 by bonding the adhesive layer 22 and the base layer 21 together.

[0126] In the synthesis step, for example, an acrylic copolymer intermediate is synthesized by radically polymerizing a C6 to C12 alkyl (meth)acrylate monomer having 6 or more and 12 or less carbon atoms in the alkyl portion and a hydroxy group-containing (meth)acrylic monomer. Radical polymerization can be carried out by a common method. For example, the above-mentioned monomers are dissolved in a solvent, stirred under heating, and a polymerization initiator is added to synthesize an acrylic copolymer intermediate. In order to adjust the molecular weight of the acrylic copolymer, polymerization may be carried out in the presence of a chain transfer agent. Next, some of the hydroxyl groups in the hydroxyl group-containing (meth)acrylate units contained in the acrylic copolymer intermediate are bonded to the isocyanate groups of the isocyanate group-containing polymerizable monomer by a urethane reaction, whereby some of the hydroxyl group-containing (meth)acrylate units become polymerizable (meth)acrylate units containing a radically polymerizable carbon-carbon double bond. The urethane reaction can be carried out by a conventional method. For example, the acrylic copolymer intermediate and the isocyanate group-containing polymerizable monomer are stirred under heating in the presence of a solvent and a urethane catalyst. This allows the isocyanate groups of the isocyanate group-containing polymerizable monomer to form a urethane bond with some of the hydroxy groups of the acrylic copolymer intermediate.

[0127] In the pressure-sensitive adhesive layer preparation step, for example, an acrylic copolymer, an isocyanate compound, and a polymerization initiator are dissolved in a solvent to prepare a pressure-sensitive adhesive composition. The viscosity of the composition can be adjusted by changing the amount of solvent. Next, the pressure-sensitive adhesive composition is applied to a release liner. Typical application methods include roll coating, screen coating, and gravure coating. The applied composition is then subjected to a solvent removal treatment, a solidification treatment, or the like to solidify the applied pressure-sensitive adhesive composition, thereby preparing the pressure-sensitive adhesive layer 22.

[0128] In the base layer preparation step, the base layer can be prepared by film formation using a general method. Examples of film formation methods 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. Commercially available films may also be used as the base layer 21 or as each layer constituting the base layer 21.

[0129] In the lamination step, the pressure-sensitive adhesive layer 22, which is superimposed on the release liner, is laminated on the base layer 21. The release liner may remain superimposed on the pressure-sensitive adhesive layer 22 until use. In addition, in order to promote the reaction between the crosslinking agent and the acrylic copolymer, and also between the crosslinking agent and the surface portion of the base layer 21, an aging treatment step may be carried out for 48 hours in an environment of 50°C after the lamination step.

[0130] Through these steps, the dicing tape 20 can be manufactured.

[0131] <Process of overlapping the die bond sheet and dicing tape> 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.

[0132] In such attachment, the release liners are peeled off from the pressure-sensitive adhesive layer 22 of the dicing tape 20 and the die bond sheet 10, respectively, and the die bond sheet 10 and the pressure-sensitive adhesive layer 22 are attached together so that they come into direct contact with each other. For example, they can be attached by pressure bonding. The temperature during attachment is not particularly limited, and is, for example, from 30°C to 50°C, and preferably from 35°C to 45°C. The linear pressure during attachment is not particularly limited, but is preferably from 0.1 kgf / cm to 20 kgf / cm, and more preferably from 1 kgf / cm to 10 kgf / cm.

[0133] The dicing die bond film 1 manufactured as described above through the above-mentioned steps is used, for example, as an auxiliary tool for manufacturing a semiconductor device (semiconductor integrated circuit).

[0134] A method for manufacturing a semiconductor device using the above-mentioned dicing die bond film 1 is, for example, a method for manufacturing a semiconductor device, in which a plurality of semiconductor chips are obtained from a semiconductor wafer and a semiconductor device having at least one of the semiconductor chips is manufactured, a mounting step of fixing the semiconductor wafer on the die bond sheet; an expanding step of cleaving the semiconductor wafer together with the die bond sheet on the adhesive layer by stretching the dicing tape to obtain the plurality of semiconductor chips from the semiconductor wafer; a pick-up step of peeling off each small piece of the die bond sheet attached to each of the plurality of semiconductor chips from the adhesive layer to pick up the plurality of semiconductor chips one by one; One day or more is allowed to pass from when the dicing tape is stretched until all of the semiconductor chips are picked up.

[0135] The method for manufacturing a semiconductor device (method for using a dicing die bond film) will be described in more detail below.

[0136] <Method for manufacturing a semiconductor device (method for using a dicing die bond film when manufacturing a semiconductor device)> In a manufacturing method of a semiconductor device, semiconductor chips are generally cut out from a semiconductor wafer having a circuit surface formed thereon and then assembled. At this time, the dicing die bond film of this embodiment is used as a manufacturing auxiliary tool.

[0137] The method for manufacturing a semiconductor device according to this embodiment includes the steps of: A method for manufacturing a semiconductor device, which uses a dicing die bond film comprising a dicing tape having a base layer and an adhesive layer overlaid on the base layer, and a die bond sheet overlaid on the dicing tape, to manufacture a semiconductor device having a semiconductor chip. The manufacturing method of the semiconductor device of this embodiment includes a mounting step of attaching one side of a semiconductor wafer to the die bond sheet 10 of the dicing die bond film 1 described above and fixing the semiconductor wafer to the dicing tape 20 via the die bond sheet 10; and an expanding step of stretching the dicing tape (20) to cleave the semiconductor wafer together with the die bond sheet (10) at the fragile portion of the semiconductor wafer as a boundary. Furthermore, the manufacturing method of the semiconductor device of this embodiment includes a pick-up step of peeling the small pieces of die bond sheet 10 attached to the adhesive layer 22 of the dicing tape 20 from the adhesive layer 22 together with the semiconductor chip.

[0138] In detail, the manufacturing method of the semiconductor device of this embodiment includes, for example, a stealth dicing process in which a weak portion is formed inside a semiconductor wafer to which a backgrind tape has been attached using laser light, and the semiconductor wafer is prepared for processing into semiconductor 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; the 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 via the die bond sheet 10; the expanding process in which the dicing tape 20 is stretched to fractur e the semiconductor wafer to produce semiconductor chips and widen the spacing between adjacent semiconductor chips; and the pick-up process in which the die bond sheet piece 10' is peeled off from the adhesive layer 22 to remove the semiconductor chip (die) with the die bond sheet piece 10' still attached. The manufacturing method of the semiconductor device of this embodiment further includes a die bonding process in which the small piece 10' of the die bond sheet attached to the semiconductor chip is adhered to the adherend, a curing process in which the small piece 10' of the die bond sheet adhered to the adherend is hardened, a wire bonding process in which the electrodes of the electronic circuit in the semiconductor chip are electrically connected to the adherend by wire, and a sealing process in which the semiconductor chip and wire on the adherend are sealed with a thermosetting resin.

[0139] The stealth dicing process is a step in the so-called SDBG (Stealth Dicing Before Grinding) process. In the stealth dicing process, as shown in FIGS. 3A to 3C, a weakened portion is formed inside the semiconductor wafer W to cleave a patterned wafer with a circuit surface formed thereon into semiconductor chips. Specifically, first, a backgrinding tape G is attached to the circuit surface of the semiconductor wafer W (see FIG. 3A). Next, with the backgrinding 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 FIG. 3B). Then, a laser beam is applied to the thinned semiconductor wafer W to form a weakened portion inside the semiconductor wafer W (see FIG. 3C).

[0140] Instead of the stealth dicing process, a half-cut process may be performed, which is a step in the so-called DBG (Dicing Before Grinding) process. In the half-cut process, a groove is formed in the semiconductor wafer to process the semiconductor wafer into semiconductor chips (dies) by a fracturing process, and then the semiconductor wafer is ground to reduce its thickness. Specifically, in the half-cut process, a semiconductor wafer with a circuit surface formed thereon is subjected to half-cut processing to split it into semiconductor chips (dies). More specifically, a wafer processing tape is attached to the surface of the semiconductor wafer opposite the circuit surface. With the wafer processing tape attached to the semiconductor wafer, grooves for dividing the semiconductor wafer 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.

[0141] The dicing die bond film of this embodiment is preferably used in an SDBG (Stealth Dicing Before Grinding) process or a DBG (Dicing Before Grinding) process for manufacturing semiconductor chips by cleaving a semiconductor wafer as described above.

[0142] In the back-grinding process, as shown in FIG. 3D, the semiconductor wafer W with the back-grinding tape G attached thereto is further ground to reduce the thickness of the semiconductor wafer W to the thickness of the semiconductor chips (dies) that will be fabricated in a subsequent cleaving process. For example, the half-cut semiconductor wafer W is ground to a predetermined thickness so as not to be separated. By performing the grinding process in this manner, the semiconductor wafer W is cleaved into semiconductor chips and the die bond sheet 10 is also cleaved in a subsequent expanding process (particularly a low-temperature expanding process).

[0143] In the mounting step, as shown in Figures 4A and 4B, the semiconductor wafer W is fixed to the dicing tape 20. 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 cutting process described above, is attached to the exposed surface of the die bond sheet 10 (see Figure 4A). Subsequently, the backgrinding tape G is peeled off from the semiconductor wafer W (see Figure 4B).

[0144] In the expanding step, as shown in FIGS. 5A to 5C, the semiconductor wafer W is cleaved to diced it into small pieces, producing diced semiconductor chips X, and the distance between the produced semiconductor chips X is increased. Specifically, a dicing ring R is attached to the adhesive layer 22 of the dicing tape 20, and then fixed to a holder H of an expanding device (see FIG. 5A). A push-up member U provided in the expanding device is pushed up from below the dicing die bond film 1, stretching the dicing die bond film 1 so as to expand it in the surface direction (see FIG. 5B). This cleaves the semiconductor wafer W under specific temperature conditions. The temperature conditions are, for example, −20 to 0°C, preferably −15 to 0°C, and more preferably −10 to −5°C. The expanded state is released by lowering the push-up member U (see FIG. 5C; this is the low-temperature expanding step). 6A and 6B, the dicing tape 20 is stretched to expand its area under higher temperature conditions (for example, 10°C to 25°C), thereby separating adjacent semiconductor chips X in the planar direction of the film surface after cleaving, and further widening the kerf (the distance between adjacent semiconductor chips) (room-temperature expanding process).

[0145] In this embodiment, the expanding step stretches the dicing tape 20 in the planar direction. At this time, a shrinking force may be generated in the portion (central portion) of the dicing tape 20 that overlaps with the many diced semiconductor chips, causing the dicing tape 20 to return to its original shape. However, when the dicing tape 20 is stretched by 5% and held for 3 minutes, it has a stress relaxation rate of 65% or more, so the shrinking force to return to the original shape is small. Therefore, even if a long time passes before all the semiconductor chips are picked up after the dicing tape is stretched in the expanding process, the separation distance (kerf) between adjacent semiconductor chips can be maintained.

[0146] Before the pick-up step, for example, the adhesive layer 22 overlapping the base layer 21 is irradiated with ultraviolet light from the base layer 21 side, thereby subjecting the adhesive layer 22 to a curing treatment (curing treatment step).

[0147] 7, in the pick-up process, the semiconductor chip X with the die bond sheet piece 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 and die bond sheet piece 10' to be picked up through the dicing tape 20. The pushed-up semiconductor chip X is held by a suction jig J. At this stage, the adhesive strength between the adhesive layer 22 and the small piece 10' of the die-bonding sheet is 0.30 N / 20 mm or less, and therefore, good pick-up properties are exhibited.

[0148] In the die bonding process, the semiconductor chip X with the die bond sheet piece 10' attached thereto is bonded to an adherend Z. In the die bonding process, for example, as shown in FIG. 8, the semiconductor chips X with the die bond sheet piece 10' attached thereto may be stacked multiple times.

[0149] After repeating the above-mentioned pick-up process and die bonding process, i.e., after the numerous semiconductor chips produced by cutting the semiconductor wafer are picked up one by one and bonded to the adherend Z, the next curing process can be carried out. In the method for manufacturing a semiconductor device of this embodiment, after some of the plurality of semiconductor chips have been picked up, the remaining plurality of semiconductor chips that have not been picked up are temporarily stored at the required timing while being held on the dicing tape 20. In other words, after the dicing tape is stretched in the expanding step, the dicing tape 20 holding the remaining plurality of semiconductor chips is stored for a relatively long time at the desired timing until all of the plurality of semiconductor chips have been picked up. The time (period) from when the dicing tape is stretched in the expanding step to when all of the semiconductor chips are picked up may be, for example, one day or more (24 hours or more), two days (48 hours) or more, or three days or more. Such a period may be, for example, 10 days or less, or 7 days or less.

[0150] During the storage, for example, a plurality of stretched dicing tapes 20 are stored. Specifically, the plurality of dicing tapes 20 are arranged so that the surface direction of each dicing tape 20 is horizontal and so that the plurality of dicing tapes 20 are spaced apart from one another in the vertical direction. At this time, no tensile force is applied to each dicing tape 20 in the surface direction. If multiple dicing tapes 20 are stored under such conditions, a significant slack may occur in one stretched dicing tape 20, which may cause it to come into contact with the dicing tape 20 directly below it. In contrast, the dicing tape 20 of the preferred embodiment described above is prevented from causing such slack.

[0151] In the curing process, a heat treatment is performed at a temperature of, for example, 100°C or higher and 180°C or lower in order to increase the reactivity of the crosslinkable groups (e.g., epoxy groups) in the above-mentioned crosslinkable group-containing acrylic polymer contained in the die bond sheet piece 10' and promote the hardening of the die bond sheet piece 10'.

[0152] In the wire bonding process, a semiconductor chip X (die) and an adherend Z are connected with a wire L while being heated (see, for example, FIG. 8).

[0153] 9, the semiconductor chip X and the small piece 10′ of the die bond sheet are sealed with a thermosetting resin M such as epoxy resin. In the sealing process, in order to promote the curing reaction of the thermosetting resin M, a heat treatment is performed at a temperature of, for example, 100° C. or higher and 180° C. or lower.

[0154] In recent years, with the further advancement of integration technology in the semiconductor industry, there has been a demand for thinner semiconductor chips (for example, a thickness of 20 μm or more and 50 μm or less) and thinner die bond sheets (for example, a thickness of 1 μm or more and 40 μm or less, preferably 7 μm or less, and more preferably 5 μm or less).

[0155] In the above-described method for manufacturing a semiconductor device (method for using a dicing die bond film), in the expanding step (particularly the room temperature expanding step), the dicing tape 20 is stretched with a strong force in the planar direction so as to expand the area of ​​the dicing tape 20. Also, as described above, multiple dicing tapes 20 holding multiple semiconductor chips that were not picked up at the desired timing are stored for, for example, several days. While the dicing tape 20 is stored for, for example, several days, the force with which the stretched dicing tape 20 tries to return to its original shape may cause the distance between adjacent semiconductor chips to become smaller. In contrast, the dicing tape 20 has a stress relaxation rate of 65% or more when stretched by 5% and held for 3 minutes, and preferably contains the above-mentioned α-olefin copolymer or the like in the base layer 21. Therefore, the separation distance (kerf) between adjacent semiconductor chips can be maintained for a long period of time.

[0156] The dicing die bond film of this embodiment is as exemplified above, but the present invention is not limited to the dicing die bond film exemplified above. That is, various forms used in general dicing die bond films can be adopted within the range that does not impair the effects of the present invention.

[0157] The matters disclosed by this specification include the following. (1) a dicing tape having a base layer and a pressure-sensitive adhesive layer overlying one surface of the base layer; a die bond sheet overlying the pressure-sensitive adhesive layer, the dicing tape has a stress relaxation rate of 65% or more when elongated by 5% and held for 3 minutes; The pressure-sensitive adhesive layer has an adhesive strength of 0.30 N / 20 mm or less to the die-bonding sheet. (2) The dicing die bond film according to (1) above, wherein the dicing tape has a tensile storage modulus of 60 MPa or more at 25°C. (3) The dicing die bond film according to (1) or (2) above, wherein the base layer has three laminated layers. (4) The dicing die bond film according to any one of (1) to (3) above, wherein the base layer contains an α-olefin copolymer. (5) The dicing die bond film according to any one of (1) to (4) above, wherein the die bond sheet has a tensile storage modulus of 5 MPa or more and 10,000 MPa or less at 25°C. (6) The dicing die bond film according to any one of (1) to (5) above, wherein the die bond sheet has a thickness of 3 μm or more and 40 μm or less. (7) A dicing die bond film according to any one of (1) to (6) above, which is used to obtain a plurality of semiconductor chips by stretching the dicing tape while the semiconductor wafer is fixed to the die bond sheet, thereby cleaving the semiconductor wafer together with the die bond sheet and dividing the semiconductor wafer into small pieces. (8) A method for manufacturing a semiconductor device, comprising obtaining a plurality of semiconductor chips from a semiconductor wafer using the dicing die bond film according to any one of (1) to (7) above, and manufacturing a semiconductor device having at least one of the semiconductor chips, a mounting step of fixing the semiconductor wafer on the die bond sheet; an expanding step of cleaving the semiconductor wafer together with the die bond sheet on the adhesive layer by stretching the dicing tape to obtain the plurality of semiconductor chips from the semiconductor wafer; a pick-up step of peeling off each small piece of the die bond sheet attached to each of the plurality of semiconductor chips from the adhesive layer to pick up the plurality of semiconductor chips one by one; The method for manufacturing a semiconductor device includes allowing one day or more to pass from when the dicing tape is stretched until when all of the plurality of semiconductor chips are picked up. [Example]

[0158] The present invention will now be described in more detail with reference to experimental examples, but the present invention is not limited to these examples.

[0159] A dicing tape was produced as follows: The dicing tape was bonded to a die bond sheet to produce a dicing die bond film.

[0160] <Creating dicing tape> [Base material layer] The following resin raw materials (commercially available products) were used to prepare three laminated substrate layers, or one type of resin film was used as the substrate layer as is. (Resin raw material for forming the base layer) "Resin A" α-olefin copolymer Melting point: 130°C Tensile modulus: 1200 [MPa] (25°C) (Product name: Absoutomer P1013, manufactured by Mitsui Chemicals) ·“Resin B” mixed resin α-olefin copolymer Mitsui Chemicals Absortomer P1013 / P1001 (mixed in a 5 / 5 mass ratio) ·"Resin C" α-olefin copolymer Tensile modulus 400 [MPa] (25°C) (Product name: Absoutomer P1001, manufactured by Mitsui Chemicals) · “Resin D” mixture Main component: Propylene elastomer resin Contains random ethylene distribution and isotactic propylene repeating units (Product name: Vistamaxx3980FL, manufactured by ExxonMobil Chemical Company) Added ingredients: Antistatic agent (polyether / polyolefin block polymer) (Product name: Pelestat 230, manufactured by Sanyo Chemical Industries, Ltd.) · “Resin E” mixture Main component: Metallocene polypropylene Polypropylene resin polymerized with a metallocene catalyst (Product name: Wintec WXK1233, manufactured by Japan Polypropylene Corporation) Added ingredients: Antistatic agent (polyether / polyolefin block polymer) (Product name: Pelestat 230, manufactured by Sanyo Chemical Industries, Ltd.) ·“Resin F” mixture Main component: Ethylene-vinyl acetate copolymer (EVA) Vinyl acetate content 10% by mass (JIS K7192) (Product name: Evaflex P1007, manufactured by Dow Mitsui Polychemicals) Added ingredients: Antistatic agent (polyether / polyolefin block polymer) (Product name: Pelestat 230, manufactured by Sanyo Chemical Industries, Ltd.) ·"Resin G" Ethylene-vinyl acetate copolymer (EVA) Vinyl acetate content 15% by mass (JIS K7192) (Product name: Ultrasen 626, manufactured by Tosoh Corporation) ·"Resin H" Polyvinyl chloride (Product name: "V9K" manufactured by Achilles) ·"Resin G" Polyvinyl chloride (Product name: V-9 (TP) Film, manufactured by Achilles)

[0161] (Forming of base layer with a three-layer laminate structure) The substrate layer was molded using an extrusion T-die molding machine. The extrusion temperature was 190°C. When producing a two-layer or three-layer laminated substrate layer, the layers were integrated by co-extrusion molding from a T-die. After the integrated substrate layer (laminate) was sufficiently solidified, the substrate layer was wound into a roll and stored. All substrate layers had a total thickness of 100 μm. The details of the structure of the substrate layer are as shown in Table 1.

[0162] [Adhesive layer α] (raw material monomer for acrylic copolymer) 2-Ethylhexyl acrylate (2EHA): 83.3 mole parts 2-Hydroxyethyl acrylate (HEA): 16.7 mole parts The above raw materials were placed in a reaction vessel equipped with a condenser, nitrogen inlet, thermometer, and stirrer. Azobisisobutyronitrile (AIBN) was used as a thermal polymerization initiator, with 0.2 parts by mass per 100 parts by mass of the monomers. Butyl acetate was added as a reaction solvent so that the total monomer concentration was 38% by mass. The polymerization reaction was carried out in a nitrogen stream at 62°C for 6 hours and then at 75°C for 2 hours, yielding an acrylic copolymer intermediate. Next, 2-methacryloyloxyethyl isocyanate (hereinafter referred to as MOI) (product name "Karenz MOI" manufactured by Showa Denko Materials Co., Ltd.) was added to the resulting solution containing the acrylic copolymer intermediate so that the amount was 80 mol % in molar terms relative to the total amount of HEA. Furthermore, 0.06 mass % of dibutyltin dilaurate relative to the MOI was added as a reaction catalyst. After that, an addition reaction treatment (urethane reaction) was carried out in an air stream at 50°C for 12 hours, yielding an acrylic copolymer. Next, a pressure-sensitive adhesive solution was prepared by adding 3 parts by mass of a photopolymerization initiator (product name "Omnirad127" manufactured by IGM) and 1.5 parts by mass of a polyisocyanate compound (product name "Coronate L" manufactured by Nippon Polyurethane Co., Ltd.) to 100 parts by mass of the acrylic copolymer. The prepared pressure-sensitive adhesive solution was applied to the treated surface of a silicone-treated PET release liner using an applicator. A heat-drying treatment was performed at 120°C for 2 minutes to form a pressure-sensitive adhesive layer with a thickness of 10 μm.

[0163] [Bonding of adhesive layer and base layer] Subsequently, each of the pressure-sensitive adhesive layers prepared as described above was attached to a base layer within 1 hour after preparation of the pressure-sensitive adhesive layer, and the resulting mixture was stored at 50° C. for 24 hours to prepare a dicing tape. When the base layer has a three-layer structure, the first base layer (outermost layer) is disposed farthest from the adhesive layer, the second base layer (middle layer) is disposed closer to the adhesive layer than the first base layer, and the third base layer (outermost layer) is superimposed on one side of the adhesive layer.

[0164] <Production of die bond sheet> Die bond sheets No. 1 and No. 2 were produced as follows. [Die Bond Sheet No.1] Crosslinkable group-containing acrylic polymer: 100 parts by weight (solid content) (Product name: "SG-70L", manufactured by Nagase ChemteX Corporation, glass transition temperature -13°C, contains carboxyl and hydroxyl groups, acid value 5mgKOH / g) Epoxy resin: 210 parts by weight (cresol novolac epoxy resin) Epoxy equivalent weight: approx. 200 (g / eq) (Product name: Epicron N-665-EXP-S, manufactured by DIC) Phenolic resin: 100 parts by weight Biphenyl type phenol novolac resin (hydroxyl equivalent: 203g / eq) (Product name: MEHC-7851SS, manufactured by UBE) Silica filler: 3 parts by weight (Product name: SE2050-MCV, manufactured by Admatechs) ·Curing catalyst: 0.5 parts by mass Tetraphenylphosphonium tetraphenylborate (Product name "TPP-K", manufactured by Hokuko Chemical Industry Co., Ltd.) The above-mentioned raw materials were added to a predetermined amount of methyl ethyl ketone and mixed to prepare a bonding composition solution having a total solid content concentration of 20 mass %. Next, the adhesive composition was applied to the silicone release-treated surface of a PET release liner (50 μm thick) using an applicator to form a coating film. This coating film was then subjected to a heat drying treatment at 130°C for 2 minutes, and a 10 μm thick die-bonding sheet was produced on the PET release liner.

[0165] [Die bond sheet No.2] Crosslinkable group-containing acrylic polymer: 100 parts by weight (solid content) (Product name "SG-70L", manufactured by Nagase ChemteX Corporation, glass transition temperature -13°C, contains carboxyl and hydroxyl groups, acid value 5mgKOH / g) Epoxy resin: 210 parts by weight (bisphenol A epoxy resin) Epoxy equivalent weight: approx. 180 (g / eq) (Product name: YL-980, manufactured by Mitsubishi Chemical Corporation) Phenolic resin: 100 parts by weight Phenol-xylylene resin (hydroxyl equivalent: 179g / eq) (Product name: MEHC-7800H, manufactured by UBE) Silica filler: 3 parts by weight (Product name: SE2050-MCV, manufactured by Admatechs) ·Curing catalyst: 0.5 parts by mass Tetraphenylphosphonium tetraphenylborate (Product name "TPP-K", manufactured by Hokuko Chemical Industry Co., Ltd.) A die bond sheet having a thickness of 10 μm was produced on a PET release liner in the same manner as in the above die bond sheet No. 1, except that the blending composition was changed to the above.

[0166] [Table 1]

[0167] (Examples 1 to 9, Comparative Examples 1 to 3) [Dicing die bond film manufacturing] At room temperature, a circular die bond sheet and a dicing tape were bonded together using a laminator to produce a dicing die bond film.

[0168] <Measurement of physical properties of dicing die bond film> The physical properties of each layer constituting the dicing die bond film of each example and each comparative example were measured as follows.

[0169] [Stress relaxation rate of dicing tape] The stress relaxation rate of the dicing tape was measured using a measuring device ("AFX-50NX" manufactured by Shimadzu Corporation) as follows. Each dicing tape was cut to obtain a strip-shaped test piece measuring 150 mm in length and 10 mm in width. The strip-shaped test piece was set in a tensile tester and measured under an atmosphere of 23°C and 50% RH. Specifically, the strip-shaped test piece was pulled under test conditions of an initial chuck distance of 300 mm and a tensile speed of 600 mm / min, stretched (elongated) to an elongation of 5%, and then stopped. The stress value was measured within a range from stopping to 180 seconds after the stretching was stopped. The stress value immediately after the 5% stretching (stress value at the time of stretching stop) was designated as A, and the stress value 180 seconds after the stretching was stopped was designated as B. The stress relaxation rate was calculated using the following formula. Stress relaxation rate (%) = [(AB) / A] x 100

[0170] [Adhesion strength between adhesive layer of dicing tape and die bond sheet] The adhesive strength between the adhesive layer of the dicing tape and the die bond sheet was examined by measuring the peel strength between them. First, a backing tape (product name "BT315" manufactured by Nitto Denko Corporation) was attached to the die bond sheet of the dicing die bond film. 2 Nitto Seiki product name "UM-810") was used to apply a strength of 150 J / cm from the dicing tape side to the dicing die bond film with backing tape attached. 2 The adhesive layer was cured by irradiating it with ultraviolet light. Then, test pieces measuring 50 mm wide x 120 mm long were cut out. Using the cut test pieces, a T-peel test was performed using a tensile tester (product name "Autograph AGS J" manufactured by Shimadzu Corporation) at a temperature of 23°C and a peel rate of 300 mm / min, and the peel strength (N / 20 mm) was measured.

[0171] [Tensile storage modulus of dicing tape] Dynamic viscoelasticity was measured using a dynamic viscoelasticity measuring device (product name "RSA-G2", manufactured by TA Instruments) to determine the storage modulus (tensile storage modulus) at 25°C. Specifically, a test piece measuring 10 mm wide x 40 mm long was cut out from a dicing tape with a thickness of 100 μm, which was prepared in the same manner as in each Example or Comparative Example. Measurements were carried out under the following conditions. The storage modulus (MPa) at 25°C was then determined. Initial distance between the chucks that hold both ends of the test piece: 22.5 mm Measurement mode: Tensile mode Measurement environment: Nitrogen atmosphere Measurement temperature range: -40℃ to 280℃ ·Measurement frequency: 10Hz Dynamic strain: 0.005% Heating rate: 10℃ / min

[0172] [Tensile storage modulus of die bond sheet] Measurement was carried out in the same manner as in the measurement of the tensile storage modulus of the dicing tape described above, except that a test piece having a width of 10 mm and a length of 40 mm was cut out from a die bond sheet having a thickness of 200 μm produced in the same manner as die bond sheet No. 1. Then, the storage modulus (MPa) at 25°C was determined. As a result, the tensile storage modulus was 390 MPa.

[0173] <Performance evaluation of dicing die bond film> The dicing die bond films of each example and each comparative example were evaluated for their performance as follows.

[0174] (Preparing the evaluation sample) As an evaluation sample, a dicing die bond film with a chip (die) fabricated using a bare wafer was prepared. Specifically, a bare wafer held on wafer processing tape (product name "UB-3083D" manufactured by Nitto Denko Corporation) was bonded to the die bond sheet of the dicing die bond film using a laminator. The wafer processing tape was then peeled off from the wafer. The bonding conditions were a bonding speed of 10 mm / s, a temperature of 50 to 80°C, and a pressure of 0.15 MPa.

[0175] (Wafer preparation) First, a wafer processing tape (product name "UB-3083D" manufactured by Nitto Denko Corporation) was attached to the first surface of a bare wafer (12 inches in diameter, 780 μm thick, manufactured by Tokyo Kako Co., Ltd.) where a modified region was to be formed. Next, a stealth dicing device (product name "DAL7360 (SDE05)" with a power of 0.25 W and a frequency of 80 kHz, manufactured by Disco Corporation) was used to form a modified region inside the bare wafer. Specifically, a laser beam focused on the side of the wafer closest to the first surface was irradiated from the back surface (second surface) opposite the first surface. The irradiation was carried out along the planned line for dividing the bare wafer. This resulted in the formation of a modified region for dicing inside the wafer (50 μm deep from the first surface of the wafer) in a 3 mm x 7 mm grid pattern by ablation due to multiphoton absorption. The wafer was then thinned to a thickness of 30 μm by grinding from the second side using a backgrinding machine (product name "DGP8760" manufactured by Disco Corporation). In this way, a wafer held by a wafer processing tape was formed. This wafer included sections for dicing the wafer into multiple chips (3 mm × 7 mm).

[0176] (Chip (die) manufacturing) The bare wafer prepared as described above was attached to a dicing die bond film. The bare wafer attached to the dicing die bond film was cleaved into small pieces by an expanding process. After the wafer processing tape was peeled off from the bare wafer, an expanding process was carried out using a die separator (product name "Die Separator DDS2300, manufactured by Disco Corporation"). In the expanding process, cool expanding was carried out, followed by room temperature expanding. Cool expansion was performed as follows. Specifically, a 12-inch diameter SUS ring frame (manufactured by Disco Corporation) was attached at room temperature to the area where the frame was to be attached on the adhesive layer of the dicing die bond film attached to the bare wafer. Subsequently, the bare wafer with the SUS ring frame attached was loaded into a die separator. Then, the wafer and die bond sheet were cleaved in a cool expander unit under the conditions of an expansion temperature of -15°C, an expansion speed of 100 mm / sec, and an expansion amount of 10 mm, to obtain multiple chips with die bond sheet layers. Furthermore, room temperature expansion was carried out under the conditions of a room temperature environment, an expansion speed of 1 mm / sec, and an expansion amount of 10 mm.

[0177] [Pickup ability] A pickup test was conducted on semiconductor chips with individualized die bond sheets attached using a device equipped with a pickup mechanism (product name "Die Bonder DB830Plus+" manufactured by Fasford). The pickup test was conducted with the pin member pushing up at a speed of 1 mm / sec and a pushing up distance of 300 μm. Five semiconductor chips were picked up, and the pickup performance was evaluated using the following evaluation criteria. (Evaluation criteria) Excellent (〇): Pickup success rate is 80% or higher Good (△): Pickup success rate is between 20% and 80% Poor (×): Pickup success rate is less than 20%

[0178] [Kerf retention] After the evaluation of the pickup property, the expander was released (the stretching force was released), and after leaving it for 7 days, the distance (kerf) between the chips with the die bond sheet was measured by microscopic observation. The distance (kerf) was measured at 10 arbitrary points in the center, and the measured values ​​were arithmetically averaged. Then, evaluation was performed according to the following evaluation criteria. (Evaluation criteria) Excellent (〇): 1 μm or more, Good (△): 0.5 μm or more and less than 1 μm Defective (×): Less than 0.5 μm

[0179] [Cracks / Loosening of Dicing Tape] After the pickup property evaluation, a plurality of dicing tapes were stacked and placed in a cassette. After 7 days, tears and loosening in the cassette were confirmed by visual observation. (Evaluation criteria) Excellent (〇): No contact with the dicing tape below. Good (△): Looseness occurs and contact occurs with the dicing tape below, but the dicing tape does not tear Poor (×): Dicing tape torn

[0180] [Storability] The storage stability was evaluated using as an index whether or not blocking occurs easily when the base layers come into contact with each other. Specifically, only the base layers prepared as described above were wound around a roll to form a wound state, and stored in a wound state in an environment of 25°C for 3 days. After storage, the base layers were unwound from the roll at a speed of 30 m / min, and the presence or absence of blocking between the base layers when unwound was visually confirmed. (Evaluation criteria) Excellent (〇): No blocking, can be unwound at a constant speed Good (△): Some blocking occurs and it is not possible to unwind at a constant speed. Defective (×): Unable to reel in

[0181] As can be seen from the above evaluation results, the dicing die bond film of the example was able to maintain the separation distance (kerf) between adjacent semiconductor chips for a long period of time compared to the dicing die bond film of the comparative example, and was able to exhibit good pickup properties. [Industrial Applicability]

[0182] The dicing die bond film of the present invention is suitably used, for example, as an auxiliary tool when manufacturing a semiconductor device (semiconductor integrated circuit). [Explanation of symbols]

[0183] 1: Dicing die bond film, 10: Die bond sheet, 20: dicing tape, 21: Base material layer, 22: Adhesive layer.

Claims

1. a dicing tape having a base layer and a pressure-sensitive adhesive layer overlying one surface of the base layer; a die bond sheet overlying the pressure-sensitive adhesive layer, the dicing tape has a stress relaxation rate of 65% or more when elongated by 5% and held for 3 minutes; The pressure-sensitive adhesive layer has an adhesive strength of 0.30 N / 20 mm or less to the die-bonding sheet.

2. The dicing die bond film according to claim 1, wherein the dicing tape has a tensile storage modulus of 60 MPa or more at 25°C.

3. The dicing die bond film according to claim 1 or 2, wherein the base material layer has three laminated layers.

4. The dicing die bond film according to claim 1 or 2, wherein the base layer contains an α-olefin copolymer.

5. The dicing die bond film according to claim 1 or 2, wherein the die bond sheet has a tensile storage modulus of 5 MPa or more and 10,000 MPa or less at 25°C.

6. The dicing die bond film according to claim 1 or 2, wherein the die bond sheet has a thickness of 3 μm or more and 40 μm or less.

7. The dicing die bond film according to claim 1 or 2, which is used to cleave the semiconductor wafer together with the die bond sheet by stretching the dicing tape while the semiconductor wafer is fixed to the die bond sheet, thereby obtaining a plurality of semiconductor chips from the semiconductor wafer.

8. A method for manufacturing a semiconductor device, comprising obtaining a plurality of semiconductor chips from a semiconductor wafer using the dicing die bond film according to claim 1 or 2, and manufacturing a semiconductor device having at least one of the semiconductor chips, a mounting step of fixing the semiconductor wafer on the die bond sheet; an expanding step of cleaving the semiconductor wafer together with the die bond sheet on the adhesive layer by stretching the dicing tape to obtain the plurality of semiconductor chips from the semiconductor wafer; a pick-up step of peeling off each small piece of the die bond sheet attached to each of the plurality of semiconductor chips from the adhesive layer to pick up the plurality of semiconductor chips one by one, The method for manufacturing a semiconductor device includes allowing one day or more to pass from when the dicing tape is stretched until when all of the plurality of semiconductor chips are picked up.

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