Adhesive tape, dicing die bond film, and method for manufacturing semiconductor device

Abstract

To provide an adhesive tape or the like which exhibits excellent pickup performance.SOLUTION: There is provided an adhesive tape or the like, the adhesive tape being used in an adhesive layer of a dicing die-bonding film that includes the adhesive layer and a die-bonding sheet overlaid on the adhesive layer. The adhesive tape contains an acrylic copolymer having, as a monomer unit, at least an aliphatic alkyl (meth)acrylate unit having an alkyl part with a carbon number of 12 or more and a crosslinking group-containing (meth)acrylate unit in a molecule. The acrylic copolymer contains 10 mol% or more and 85 mol% or less of the aliphatic alkyl (meth)acrylate unit, and also contains 15 mol% or more and 35 mol% or less of the crosslinking group-containing (meth)acrylate unit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a dicing die bond film used, for example, when manufacturing a semiconductor device, and an adhesive tape provided on the dicing die bond film. The present invention also relates to a semiconductor device manufacturing 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 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 wafer. The dicing tape has a base layer and an adhesive tape (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 of forming a circuit surface on one side of a wafer using highly integrated electronic circuits, and a back-end process of cutting chips from the wafer with the circuit surface formed and assembling them.

[0004] The post-processing includes, for example, a dicing process in which a fragile portion is formed in the wafer for splitting the wafer into small chips (dies), a mounting process in which the surface of the wafer opposite the circuit surface is attached to a die bond sheet and the wafer is fixed to a dicing tape, an expanding process in which the wafer with the fragile portion formed is split together with the die bond sheet to widen the gap between the chips, a pick-up process in which the die bond sheet is peeled off from the adhesive tape (adhesive layer) to remove the chip (die) with the die bond sheet attached, a die bond process in which the chip (die) with the die bond sheet attached is attached to an adherend via the die bond sheet, and a curing process in which the die bond sheet attached to the adherend is thermally cured. A semiconductor device is manufactured through, for example, these processes.

[0005] In the manufacturing method of the semiconductor device as described above, for example, in the above-mentioned pick-up process, a dicing die bond film is known in which the gel fraction of the adhesive layer before heating and the gel fraction after heating are specified, in order to improve the releasability when peeling off the die bond sheet together with the chip (for example, Patent Document 1).

[0006] More specifically, in the dicing die bond film described in Patent Document 1, the adhesive layer is formed from an adhesive composition containing a base polymer and a thermal crosslinking agent, and the adhesive layer has a gel fraction of less than 90% by weight before heating and changes to a gel fraction of 90% by weight or more after heating. According to the dicing die bond film described in Patent Document 1, the die bond sheet can be easily peeled off from the cured adhesive layer, and the chip can be picked up together with the die bond sheet. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-135377 Summary of the Invention [Problem to be solved by the invention]

[0008] However, it cannot be said that sufficient research has been conducted yet on adhesive tapes (adhesive layers) that can exhibit good pick-up properties, and on dicing die bond films that include such adhesive tapes.

[0009] Therefore, an object of the present invention is to provide an adhesive tape having good pick-up properties, a dicing die bond film including the adhesive tape, and a method for manufacturing a semiconductor device that can exhibit good pick-up properties. [Means for solving the problem]

[0010] In order to solve the above problems, the pressure-sensitive adhesive tape according to the present invention is a pressure-sensitive adhesive tape used as the pressure-sensitive adhesive layer of a dicing die-bonding film having a pressure-sensitive adhesive layer and a die-bonding sheet superposed on the pressure-sensitive adhesive layer, The pressure-sensitive adhesive tape contains an acrylic copolymer having, as monomer units, at least an aliphatic alkyl (meth)acrylate unit in the alkyl moiety of which carbon number is 12 or more and a crosslinkable group-containing (meth)acrylate unit in the molecule; The acrylic copolymer is characterized by containing 10 mol % or more and 85 mol % or less of the aliphatic alkyl (meth)acrylate units and 15 mol % or more and 35 mol % or less of the crosslinkable group-containing (meth)acrylate units.

[0011] The dicing die bond film according to the present invention comprises a dicing tape having a pressure-sensitive adhesive layer made of the above-mentioned pressure-sensitive adhesive tape and a base layer superposed on the pressure-sensitive adhesive layer; and a die bond sheet superimposed on the adhesive layer of the dicing tape.

[0012] The present invention also provides a method for manufacturing a semiconductor device, comprising: a cleaving step of cleaving a wafer having a circuit surface formed thereon into chips; and a pick-up step of peeling the die bond sheet attached to the adhesive tape of the dicing die bond film together with the chip from the adhesive tape. [Effects of the Invention]

[0013] The pressure-sensitive adhesive tape, dicing die bond film, and semiconductor device manufacturing method according to the present invention can exhibit good pick-up properties. [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]1A and 1B are cross-sectional views schematically illustrating a stealth dicing step in a method for manufacturing a semiconductor device. [Figure 2B] 1A and 1B are cross-sectional views schematically illustrating a stealth dicing step in a method for manufacturing a semiconductor device. [Figure 2C] 1A and 1B are cross-sectional views schematically illustrating a stealth dicing step in a method for manufacturing a semiconductor device. [Figure 2D] 1A to 1C are cross-sectional views schematically illustrating a back grinding step in the method for manufacturing a semiconductor device. [Figure 3A] 1A to 1C are cross-sectional views schematically illustrating a mounting step in a method for manufacturing a semiconductor device. [Figure 3B] 1A to 1C are cross-sectional views schematically illustrating a mounting step in a method for manufacturing a semiconductor device. [Figure 4A] 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 4B] 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 4C] 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 5A] 1A to 1C are cross-sectional views schematically illustrating an expanding step at room temperature in a method for manufacturing a semiconductor device. [Figure 5B] 1A and 1B are cross-sectional views schematically illustrating an expanding step at room temperature in a method for manufacturing a semiconductor device. [Figure 6] 1A to 1C are cross-sectional views schematically illustrating a pickup step in a method for manufacturing a semiconductor device. [Figure 7] 1A to 1C are cross-sectional views schematically illustrating a die bonding step in a method for manufacturing a semiconductor device. [Figure 8] 5A to 5C are cross-sectional views schematically illustrating 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. [Figure 10] FIG. 10 is a schematic cross-sectional view showing an example of a state in which the semiconductor chip and the die bond sheet are warped. [Figure 11] An example of an image of a cross section of an adhesive layer observed under an electron microscope (schematic diagram on the left, photograph on the right). [Figure 12] Another example of an image of a cross section of a pressure-sensitive adhesive layer observed under an electron microscope (schematic diagram on the left, photograph on the right). DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of the pressure-sensitive adhesive tape according to the present invention and a dicing die bond film including the pressure-sensitive adhesive tape will be described with reference to the drawings.

[0016] As shown in FIG. 1, the dicing die bond film 1 of this embodiment comprises a dicing tape 20 and a die bond sheet 10 laminated to an adhesive layer 22 (i.e., an adhesive tape (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 this embodiment, the adhesive tape is used as the adhesive layer 22 of the dicing tape 20. Therefore, the detailed description of the adhesive tape will be made below based on the description of the adhesive layer 22.

[0018] 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 wafer 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.

[0019] <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 the silicon wafer to be cut, and is then cut and used.

[0020] The dicing tape 20 includes a base layer 21 and an adhesive layer 22 (adhesive tape) superimposed on the base layer 21.

[0021] 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 5 μm or more and 40 μm or less. The shape and size of the pressure-sensitive adhesive layer 22 are usually the same as the shape and size of the base layer 21.

[0022] The pressure-sensitive adhesive layer 22 contains, as monomer units, an acrylic copolymer having, in the molecule, at least an aliphatic alkyl (meth)acrylate unit having 12 or more carbon atoms in the alkyl portion and a crosslinkable group-containing (meth)acrylate unit; The acrylic copolymer contains 10 mol % or more and 85 mol % or less of the aliphatic alkyl (meth)acrylate units, and 15 mol % or more and 35 mol % or less of the crosslinkable group-containing (meth)acrylate units. 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."

[0023] The acrylic copolymer has at least the aliphatic alkyl (meth)acrylate unit and the 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.

[0024] The above-mentioned aliphatic alkyl (meth)acrylate unit is derived from an aliphatic alkyl (meth)acrylate monomer. In other words, the molecular structure obtained after the polymerization reaction of the aliphatic alkyl (meth)acrylate monomer is an aliphatic alkyl (meth)acrylate unit. The term "alkyl" refers to the hydrocarbon moiety ester-bonded to (meth)acrylic acid.

[0025] The alkyl portion (hydrocarbon) in the aliphatic alkyl (meth)acrylate unit may be a saturated hydrocarbon or an unsaturated hydrocarbon. The alkyl portion (hydrocarbon) in the aliphatic alkyl (meth)acrylate unit may be a straight-chain hydrocarbon, a branched-chain hydrocarbon, or may contain a cyclic structure. The number of carbon atoms in the alkyl portion (hydrocarbon) of the aliphatic alkyl (meth)acrylate unit may be 22 or less, 18 or less, or 14 or less.

[0026] The acrylic copolymer preferably contains, as the aliphatic alkyl (meth)acrylate unit, an aliphatic alkyl (meth)acrylate unit in which the alkyl portion is a saturated hydrocarbon, more preferably an aliphatic saturated alkyl (meth)acrylate unit in which the alkyl portion is a saturated hydrocarbon having 10 to 14 carbon atoms, and even more preferably a straight-chain aliphatic saturated alkyl (meth)acrylate unit in which the alkyl portion is a straight-chain saturated hydrocarbon having 10 to 14 carbon atoms.

[0027] The aliphatic alkyl (meth)acrylate unit preferably does not contain any of the following polar groups in the molecule: a benzene ring, an ether bond (-CH2-O-CH2-), an -OH group, or a -COOH group. In the aliphatic alkyl (meth)acrylate unit, 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 10 to 18 carbon atoms. When the acrylic copolymer contains an aliphatic alkyl (meth)acrylate unit, it can exhibit better pick-up properties.

[0028] The structure of the alkyl portion (hydrocarbon portion) of the aliphatic alkyl (meth)acrylate unit may be, for example, a saturated linear alkyl structure having 12 or more carbon atoms. Specific examples of the aliphatic alkyl (meth)acrylate unit include lauryl (meth)acrylate, myristyl (meth)acrylate, palmityl (meth)acrylate, stearyl (meth)acrylate, and behenyl (meth)acrylate units. The alkyl portion (hydrocarbon portion) of the aliphatic alkyl (meth)acrylate unit may be a saturated branched chain, for example, an isostearyl (meth)acrylate unit.

[0029] The acrylic copolymer may contain one type of the aliphatic alkyl (meth)acrylate unit alone, or may contain two or more types.

[0030] The acrylic copolymer may further contain saturated branched alkyl (meth)acrylate units in which the carbon number in the alkyl portion is from 7 to 11. This allows for better pick-up properties to be exhibited.

[0031] 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. Specifically, examples of the saturated branched alkyl (meth)acrylate unit include isoheptyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, isodecyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate units. Among these, at least one of the isononyl (meth)acrylate unit and the 2-ethylhexyl (meth)acrylate unit is preferred because it can exhibit good pick-up properties and can suppress so-called chip lifting in the expanding step described above.

[0032] The acrylic copolymer preferably contains lauryl (meth)acrylate units and at least one of 2-ethylhexyl (meth)acrylate units and isononyl (meth)acrylate units, thereby achieving better pick-up properties.

[0033] The crosslinkable group-containing (meth)acrylate units contained in the acrylic copolymer have 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 units have 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 an unreacted hydroxy group, and the other part (all others) have no hydroxy group but have a radically polymerizable carbon-carbon double bond.

[0034] 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.

[0035] In this embodiment, the hydroxy group-containing (meth)acrylate unit is 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-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 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.

[0036] 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.

[0037] In this embodiment, the acrylic copolymer preferably 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.

[0038] 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.

[0039] Since the acrylic copolymer contains a radically polymerizable carbon-carbon double bond in the polymerizable (meth)acrylate unit, the pressure-sensitive adhesive layer 22 can be more sufficiently 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 action of these radicals can cause a cross-linking reaction between the acrylic copolymers. 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 smoothly 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.

[0040] 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.

[0041] 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.

[0042] In this embodiment, the acrylic copolymer may contain a monomer unit other than the above-mentioned monomer units, such as (meth)acryloylmorpholine, N-vinyl-2-pyrrolidone, or acrylonitrile units.

[0043] 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.

[0044] As described above, the acrylic copolymer contains 10 mol % or more and 85 mol % or less of aliphatic alkyl (meth)acrylate units among the monomer units. The acrylic copolymer preferably contains 15 mol % or more, and more preferably 30 mol % or more, of aliphatic alkyl (meth)acrylate units. The acrylic copolymer preferably contains 80 mol % or less, more preferably 50 mol % or less, and even more preferably 40 mol % or less of aliphatic alkyl (meth)acrylate units. This allows the adhesive strength between the die bond sheet 10 and the pressure-sensitive adhesive layer 22 before curing to be more sufficiently maintained, thereby more sufficiently suppressing chip lifting, and also allows for better peelability between the die bond sheet 10 and the pressure-sensitive adhesive layer 22 after curing, resulting in better pickup properties.

[0045] As described above, the acrylic copolymer contains 15 to 35 mol % of crosslinkable group-containing (meth)acrylate units in the monomer units. In other words, the total amount of hydroxyl group-containing (meth)acrylate units having a hydroxyl group in the molecule and polymerizable (meth)acrylate units accounts for 15 to 35 mol % of the monomer units.

[0046] The acrylic copolymer preferably contains 15 mol % or more, and more preferably 20 mol % or more, of hydroxy group-containing (meth)acrylate units having hydroxy groups in the molecule. The acrylic copolymer preferably contains 35 mol % or less, and more preferably 30 mol % or less, of hydroxy group-containing (meth)acrylate units having hydroxy groups in the molecule. This allows the adhesive strength between the die bond sheet 10 and the pressure-sensitive adhesive layer 22 before curing to be more sufficiently maintained, thereby more sufficiently suppressing chip lifting. Furthermore, the die bond sheet 10 can be more easily peeled from the pressure-sensitive adhesive layer 22 after curing, resulting in better pickup properties.

[0047] The acrylic copolymer preferably contains polymerizable (meth)acrylate units having a radically polymerizable carbon-carbon double bond in an amount of 5 mol % to 35 mol %, more preferably 8 mol % to 31 mol %, of the monomer units, which allows for better pick-up properties.

[0048] In the acrylic copolymer, the proportion of saturated branched alkyl (meth)acrylate units having 7 to 11 carbon atoms in the alkyl moiety among the monomer units is preferably 20 to 70 mol %, more preferably 30 to 60 mol %, which allows for good pickup properties and further suppresses so-called tip lift.

[0049] 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. The isocyanate compound may be a compound synthesized through a urethane reaction or the like.

[0050] Examples of the isocyanate compound include diisocyanates such as aliphatic diisocyanates, alicyclic diisocyanates, and araliphatic diisocyanates.

[0051] Furthermore, examples of the isocyanate compound include polymerized polyisocyanates such as dimers and trimers of diisocyanates, and polymethylene polyphenylene polyisocyanates.

[0052] 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. can also be used. The above isocyanate compounds can be used alone or in combination of two or more.

[0053] 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.

[0054] 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.

[0055] 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 release agents. The types and amounts of the other components may be appropriately selected depending on the purpose.

[0056] The pressure-sensitive adhesive layer 22 has a phase-separated structure when its cross section is observed with an electron microscope. Specifically, the pressure-sensitive adhesive layer 22 has a first phase containing radically polymerizable carbon-carbon double bonds and a second phase that is separate from the first phase and has a lower content of radically polymerizable carbon-carbon double bonds than the first phase. When its cross section is observed with an electron microscope, for example, the first phase appears darker and the second phase appears lighter. Specifically, when a sample for electron microscope observation is prepared and stained with OsO4, osmium reacts with unsaturated bonds (double bonds), and the reacted portions appear darker. Therefore, for example, the first phase appears darker, providing contrast in the observed image.

[0057] The phase-separated structure may be, for example, an island-in-a-sea structure in which the first phase is dispersed in a continuous second phase, as shown in Fig. 11. Alternatively, the phase-separated structure may be, for example, a bicontinuous phase-separated structure in which the first phase and the second phase are each continuous, as shown in Fig. 12.

[0058] When a cross section of the pressure-sensitive adhesive layer 22 is observed by an electron microscope under the following measurement conditions, the area ratio occupied by the first phase is preferably 50% or more, more preferably 60% or more, and may be 100% or less, or 90% or less. (Measurement conditions) -Method for preparing measurement samples from the adhesive layer: Ultrathin sectioning using an ultramicrotome Magnification: 12,000x Observation area: at least 9μm 2 (For example, a 3 μm square) Staining and processing method for measurement samples: OsO4 and RuO4 - Calculation method for area ratio: Image analysis using the product name "ImageJ" In addition, in the observation image of the measurement sample prepared through the dyeing process as described above, there may be cases where parts that appear black and parts that appear gray coexist due to the influence of the content of unsaturated bonds (double bonds) in the pressure-sensitive adhesive layer 22. In this case, both the parts that appear black and the parts that appear gray are considered to be the first phase. In other words, the part with the lowest content of unsaturated bonds (double bonds) is the second phase, and the other parts are the first phase.

[0059] In this embodiment, the base layer 21 overlaid on the pressure-sensitive adhesive layer 22 may have a single layer structure or a laminated structure. Each layer of the base material layer 21 is, for example, a metal foil, a fiber sheet such as paper or cloth, a rubber sheet, or a resin film. Examples of the fiber sheet that constitutes the base material layer 21 include paper, woven fabric, and nonwoven fabric. Examples of materials for the resin film include polyolefins such as polyethylene (PE), polypropylene (PP), and ethylene-propylene copolymers; ethylene copolymers such as ethylene-vinyl acetate copolymer (EVA), ionomer resins, ethylene-(meth)acrylic acid copolymers, and ethylene-(meth)acrylic acid ester (random or alternating) copolymers; polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBT); polyacrylates; polyvinyl chloride (PVC); polyurethanes; polycarbonates; polyphenylene sulfide (PPS); polyamides such as aliphatic polyamides and wholly aromatic polyamides (aramids); polyether ether ketones (PEEK); polyimides; polyetherimides; polyvinylidene chloride; ABS (acrylonitrile-butadiene-styrene copolymers); cellulose or cellulose derivatives; silicone-containing polymers; and fluorine-containing polymers. These may be used alone or in combination of two or more.

[0060] The base layer 21 is preferably made of a polymer material such as a resin film. When the base layer 21 has a resin film, the resin film may be subjected to a stretching process or the like to control the deformability such as elongation. The surface of the base layer 21 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. Additionally, 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.

[0061] The base layer 21 may be a single layer, or may be made up of multiple layers (for example, three layers). The thickness (total thickness) of the base layer 21 may be 80 μm or more and 150 μm or less.

[0062] 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. The base layer 21 is preferably a light-transmitting (ultraviolet-transmitting) resin film or the like, since it allows active energy rays such as ultraviolet rays to be applied to the pressure-sensitive adhesive layer 22 from the back side.

[0063] The dicing tape 20 described above may include a release sheet that covers one surface of the adhesive layer 22 (the surface where the adhesive layer 22 does not overlap the base layer 21) before use. The release sheet is used to protect the adhesive layer 22, and is peeled off before the die bond sheet 10 is attached to the adhesive layer 22.

[0064] The release sheet 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 sheet can be used as a support material for supporting the pressure-sensitive adhesive layer 22. In particular, the release sheet is preferably used when the pressure-sensitive adhesive layer 22 is overlaid on the base material layer 21. More specifically, the pressure-sensitive adhesive layer 22 is overlaid on the base material layer 21 in a state where the release sheet and the pressure-sensitive adhesive layer 22 are laminated, and after overlaying, the release sheet is peeled off (transferred), thereby overlaying the pressure-sensitive adhesive layer 22 on the base material layer 21.

[0065] The dicing die bond film 1 of this embodiment may be provided with a release sheet that covers one surface of the die bond sheet 10 (the surface of the die bond sheet 10 that is not overlapped with the pressure-sensitive adhesive layer 22) before use. The release sheet is used to protect the die bond sheet 10, and is peeled off immediately before attaching an adherend (for example, a semiconductor wafer) to the die bond sheet 10. This release sheet can be used as a support material for supporting the die bond sheet 10. The release sheet is suitably used when overlaying the die bond sheet 10 on the adhesive layer 22. More specifically, the die bond sheet 10 is overlaid on the adhesive layer 22 in a state where the release sheet and the die bond sheet 10 are laminated, and after overlaying, the release sheet is peeled off (transferred), thereby overlaying the die bond sheet 10 on the adhesive layer 22.

[0066] <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.

[0067] Regarding the peel strength between the pressure-sensitive adhesive layer 22 and the die-bonding sheet 10, the peel strength (A) before the pressure-sensitive adhesive layer 22 is cured by active energy rays and the peel strength (B) after curing preferably satisfy the following formula (1), more preferably the following formula (2). Note that the value of (A) / (B) below may be 25.0 or less. (A) / (B)>7.0 Equation (1) (A) / (B)>8.0 Formula (2) By satisfying the above formula (1), better pick-up properties can be exhibited. In order to measure the peel strength (B) after curing, the adhesive layer 22 is sufficiently cured before the peel strength is measured. For example, a high-pressure mercury lamp (60 mW / cm 2 ) from the substrate layer side with an intensity of at least 150 mJ / cm 2 The pressure-sensitive adhesive layer is cured by irradiating it with active energy rays.

[0068] The peel strength between the pressure-sensitive adhesive layer 22 and the die bond sheet 10 may be 0.30 [N / 20 mm] or more, or 0.50 [N / 20 mm] or more, before the pressure-sensitive adhesive layer 22 is cured by active energy rays (i.e., the value of (A) above). The value of (A) may be 2.50 [N / 20 mm] or less, less than 1.90 [N / 20 mm], or 1.80 [N / 20 mm] or less. This makes it possible to more sufficiently suppress so-called chip lifting.

[0069] The peel strength between the pressure-sensitive adhesive layer 22 and the die-bonding sheet 10 after the pressure-sensitive adhesive layer 22 is cured by active energy rays (i.e., the value of (B) above) may be 0.03 [N / 20 mm] or more, 0.06 [N / 20 mm] or more, or 0.07 [N / 20 mm] or more. The value of (A) may be 0.10 [N / 20 mm] or less, less than 0.09 [N / 20 mm], or 0.08 [N / 20 mm] or less. This allows for better pickup properties to be exhibited.

[0070] The value of (A) can be increased, for example, by increasing the content of radically polymerizable carbon-carbon double bonds in the acrylic copolymer in the pressure-sensitive adhesive layer 22. In addition, the value of (A) can be increased, for example, by increasing the content of the hydroxy group-containing (meth)acrylate units in the acrylic copolymer. The value of (B) can be further reduced, for example, by increasing the content of radically polymerizable carbon-carbon double bonds in the acrylic copolymer in the pressure-sensitive adhesive layer 22. In addition, the value of (B) can be further reduced by increasing the content of the aliphatic alkyl (meth)acrylate units in the acrylic copolymer. By changing (A) and (B) in the above manner, the value of (A) / (B) can be adjusted.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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).

[0075] 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).

[0076] In the present embodiment, the crosslinkable group-containing acrylic polymer contained in the die bond sheet 10 preferably contains at least one of a carboxy group and an epoxy group as a crosslinkable group, thereby allowing the die bond sheet 10 to be more favorably adhered to the adherend. The die bond sheet 10 is required to have a relatively high cohesive strength after curing in order to more fully exhibit adhesion to an adherend after curing (described in detail later). To increase the cohesive strength after curing, the organic components contained in the die bond sheet 10 must undergo a sufficient crosslinking reaction with each other, and the die bond sheet 10 must be sufficiently cured. To allow sufficient curing to proceed, the crosslinkable group-containing acrylic polymer preferably has a relatively highly reactive functional group such as an epoxy group (glycidyl group) or a carboxy group.

[0077] 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, or 0.5% by mass or more and 40.0% by mass or less, more preferably 1.0% by mass or more and 30.0% by mass or less, and even more preferably 3.0% by mass or more and 20.0% by mass or less. When the above ratio is 0.1% by mass or more, it is possible to more sufficiently proceed with curing when the die bond sheet 10 is subjected to a thermal curing treatment. On the other hand, when the above ratio is 60.0% by mass or less, it is possible to appropriately suppress the crosslinking reactivity of the crosslinkable group-containing acrylic polymer and improve stability over time. When the crosslinkable group-containing acrylic polymer has a hydroxy group or a carboxy group as a crosslinkable group in the molecule, the proportion of the structural units of the crosslinkable group-containing monomer in the crosslinkable group-containing acrylic polymer may be 0.1% by mass or more and 20.0% by mass or less, or may be 0.5% by mass or more and 10.0% by mass or less, more preferably 0.8% by mass or more and 15.0% by mass or less, and even more preferably 1.0% by mass or more and 10.0% by mass or less. When the crosslinkable group-containing acrylic polymer has an epoxy group as a crosslinkable group in the molecule, the proportion of the epoxy group-containing structural unit in the crosslinkable group-containing acrylic polymer may be 5% by mass or more and 60% by mass or less, or 6% by mass or more and 40% by mass or less, and more preferably 7% by mass or more and 20% 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.

[0078] The die bond sheet 10 of the present embodiment may contain one type of crosslinkable group-containing acrylic polymer, or may contain multiple types (for example, two types) of crosslinkable group-containing acrylic polymers.

[0079] For example, when the die bond sheet 10 contains two types of crosslinkable group-containing acrylic polymers, the crosslinkable groups of one of the two types of crosslinkable group-containing acrylic polymers crosslink with the crosslinkable groups of the other. Specifically, a crosslinkable group-containing acrylic polymer having at least one of a hydroxy group or a carboxy group as a crosslinkable group in the molecule and a crosslinkable group-containing acrylic polymer having at least one of an epoxy group or an isocyanate group as a crosslinkable group in the molecule can crosslink with each other.

[0080] The above-mentioned crosslinkable group-containing acrylic polymer can be synthesized by a general polymerization method using, for example, a radical polymerization initiator.

[0081] The crosslinkable group-containing acrylic polymer preferably contains alkyl(meth)acrylate monomers in the largest proportion by mass among the constituent units in the molecule. Examples of the alkyl(meth)acrylate monomers include C1-C18 alkyl(meth)acrylate monomers having an alkyl group (hydrocarbon group) with 1 to 18 carbon atoms.

[0082] Examples of the alkyl(meth)acrylate monomer include saturated linear alkyl(meth)acrylate monomers and saturated branched alkyl(meth)acrylate monomers.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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).

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] Phenol resins can act as curing agents for epoxy resins, and examples of such 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.

[0092] 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. Also, the die bond sheet 10 may contain a plurality of types of crosslinkable group-containing acrylic polymers, which undergo a crosslinking reaction with each other.

[0093] For example, the die bond sheet 10 may contain a carboxy group-containing acrylic polymer or a hydroxy group-containing acrylic polymer as the crosslinkable group-containing acrylic polymer, and an epoxy resin as the thermosetting resin, whereby the carboxy group or hydroxy group of the crosslinkable group-containing acrylic polymer and the epoxy group of the epoxy resin undergo a crosslinking reaction to sufficiently harden the die bond sheet 10.

[0094] 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.

[0095] The content ratio of the above-mentioned crosslinkable group-containing acrylic polymer relative to the total mass of the die bond sheet 10 is preferably 8 parts by mass or more and 100 parts by mass or less, more preferably 30 parts by mass or more, and even more preferably 40 parts by mass or more.

[0096] In the die bond sheet 10, the content 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 40 parts by mass or more and 98 parts by mass or less, and even more preferably 60 parts by mass or more. Note that by changing the content 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 relative to 100 parts by mass of the organic component may be 40 parts by mass or less, or may be 10 parts by mass or less.

[0097] 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. 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.

[0098] When the die bond sheet 10 contains a filler, the content of the filler may be 50 mass % or less, 40 mass % or less, or 30 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.

[0099] 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.

[0100] 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.

[0101] The thickness of the die bond sheet 10 is not particularly limited, but is, for example, 1 μm or more and 200 μm or less. Such a thickness may be 3 μm or more and 150 μm or less, or 5 μm or more and 100 μm or less. When the die bond sheet 10 is a laminate, the above thickness is the total thickness of the laminate.

[0102] 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 two or more different compositions are laminated together. When the die bond sheet 10 has a multilayer structure, at least one layer constituting the die bond sheet 10 contains the above-mentioned crosslinkable group-containing acrylic polymer and, if necessary, further contains a thermosetting resin.

[0103] Next, a method for manufacturing the die bond sheet 10 and the dicing die bond film 1 of this embodiment will be described.

[0104] <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.

[0105] <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.

[0106] In the resin composition preparation step, for example, the above-mentioned crosslinkable group-containing acrylic polymer is mixed with either an epoxy resin, an epoxy resin curing catalyst, a phenolic resin, or a solvent, and each resin is dissolved in the solvent to prepare 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.

[0107] In the die-bonding sheet forming step, for example, the resin composition prepared as described above is applied to a release sheet. 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.

[0108] <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.

[0109] In the synthesis step, for example, an acrylic copolymer intermediate is synthesized by radically polymerizing a C9 to C11 alkyl (meth)acrylate monomer 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.

[0110] 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 sheet. Typical application methods, such as roll coating, screen coating, and gravure coating, are used. 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.

[0111] 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.

[0112] In the lamination step, the pressure-sensitive adhesive layer 22, which is superimposed on the release sheet, is laminated on the base material layer 21. The release sheet 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 process may be carried out for 48 hours in an environment of 50°C after the lamination process.

[0113] Through these steps, the dicing tape 20 can be manufactured.

[0114] <Step of Overlapping the Die Bonding Sheet 10 and the Dicing Tape 20> In the step of overlapping the die bond sheet 10 and the dicing tape 20, the die bond sheet 10 is attached to the adhesive layer 22 of the dicing tape 20 manufactured as described above.

[0115] In such attachment, the release sheets are peeled off from the adhesive layer 22 of the dicing tape 20 and the die bond sheet 10, respectively, and the die bond sheet 10 and the adhesive layer 22 are 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.

[0116] The dicing die bond film 1 manufactured as described above through the above-described steps is used, for example, as an auxiliary tool for manufacturing a semiconductor device (semiconductor integrated circuit). A method for manufacturing a semiconductor device (a method for using the dicing die bond film) will be described below.

[0117] <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, generally, chips are cut out from a semiconductor wafer on which a circuit surface is formed and then assembled. At this time, the dicing die bond film of this embodiment is used as a manufacturing auxiliary tool.

[0118] The method for manufacturing a semiconductor device according to this embodiment includes the steps of: a cleaving step of cleaving the wafer (semiconductor wafer) on which the circuit surface is formed into chips; The method further includes a pick-up step of peeling the die bond sheet attached to the adhesive layer (adhesive tape) of the dicing die bond film together with the chip from the adhesive layer (adhesive tape).

[0119] In the manufacturing method of the semiconductor device of this embodiment, the cleaving process 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 chips (dies) by a cleaving process; a backgrinding process in which the semiconductor wafer to which the backgrind tape has been attached is ground to reduce its thickness; a mounting process in which one side of the thinned semiconductor wafer (for example, the side opposite to the circuit side) is attached to a die bond sheet 10 and the semiconductor wafer is fixed to the dicing tape 20; and an expanding process in which the dicing tape 20 is stretched to cleave the semiconductor wafer to produce chips (dies) and widen the spaces between the chips. In the pick-up step, the die bond sheet 10 and the adhesive layer 22 are peeled away from each other, and the semiconductor chip (die) is taken out with the die bond sheet 10 still attached. The manufacturing method of the semiconductor device of this embodiment further includes a die bonding process in which the die bond sheet 10 attached to the semiconductor chip (die) is adhered to an adherend, a curing process in which the die bond sheet 10 adhered to the adherend is hardened, a wire bonding process in which the electrodes of the electronic circuit in the semiconductor chip (die) are electrically connected to the adherend by wires, and a sealing process in which the semiconductor chip (die) and wires on the adherend are sealed with a thermosetting resin.

[0120] 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. 2A to 2C, a weakened portion is formed inside the semiconductor wafer W to split the wafer, on which the circuit surface is formed, into chips (dies). More specifically, a backgrinding tape G is attached to the circuit surface of the semiconductor wafer W (see FIG. 2A). 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. 2B). A laser beam is applied to the thinned semiconductor wafer W to form a weakened portion inside the semiconductor wafer W (see FIG. 2C).

[0121] 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, grooves are formed in the semiconductor wafer to process the semiconductor wafer into chips (dies) by a fracturing process, and then the semiconductor wafer is ground to reduce its thickness. Specifically, in the half-cut process, a half-cut process is performed to divide a wafer with a circuit surface into chips (dies). More specifically, a wafer processing tape is attached to the surface of the semiconductor wafer opposite the circuit surface. A dicing ring is also attached to the wafer processing tape. With the wafer processing tape attached, grooves for division are formed. A backgrind tape is attached to the surface with the grooves formed, while the wafer processing tape that was initially attached is peeled off.

[0122] As described above, 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.

[0123] In the back-grinding process, as shown in FIG. 2D , 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 chips (dies) to be fabricated in a subsequent cleaving process. For example, the half-cut semiconductor wafer W may be ground until it reaches a predetermined thickness so as not to be separated. If the grinding process is performed in this manner, the semiconductor wafer W will be cleaved into chips and the die bond sheet 10 will also be cleaved in a subsequent expanding process (particularly a low-temperature expanding process). On the other hand, the grinding process may be performed until the half-cut semiconductor wafer W is cleaved. If the grinding process is performed in this manner, the die bond sheet 10 will be cleaved in a subsequent expanding process (particularly a low-temperature expanding process), for example, while widening the gap between adjacent chips.

[0124] 3A and 3B, in the mounting step, 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 FIG. 3A). Subsequently, the backgrinding tape G is peeled off from the semiconductor wafer W (see FIG. 3B).

[0125] Before the expanding step, the die bond sheet 10 may be cleaved by, for example, irradiation with laser light. Specifically, when the semiconductor wafer W is separated by the above-mentioned cutting process, the die bond sheet 10 that overlaps the chips formed by separating the semiconductor wafer but has not yet been cleaved may be cut by irradiation with laser light. Thereafter, the gap between adjacent chips may be widened by the expanding step.

[0126] In the expanding step, as shown in FIGS. 4A to 4C, the spacing between the semiconductor chips (dies) X produced by cleaving 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. 4A). 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 planar direction (see FIG. 4B). 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. 4C; this is the low-temperature expanding step). 5A and 5B, 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 after cleaving in the planar direction of the film surface and further widening the kerf (gap) (room-temperature expanding process). When the above-mentioned DBG process is carried out, a method of cutting the die bond sheet at a low temperature may be adopted in the expanding step, or a method of cutting the die bond sheet with a laser may be adopted. When cutting the die bond sheet with a laser, the expanding step may be carried out at a lower temperature after cutting the die bond sheet.

[0127] 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).

[0128] 6, in the pick-up process, the semiconductor chip X with the die bond sheet 10 attached thereto is peeled off from the adhesive layer 22 of the dicing tape 20. More specifically, the pin members P are raised to push up the semiconductor chip X to be picked up through the dicing tape 20. The pushed-up semiconductor chip X is held by a suction jig J. By using the dicing die bond film of the present embodiment described above, good pick-up properties can be exhibited in the pick-up step.

[0129] In the die bonding process, the semiconductor chip X with the die bond sheet 10 attached thereto is bonded to an adherend Z. In the die bonding process, for example, as shown in FIG. 7, the semiconductor chips X with the die bond sheet 10 attached thereto may be stacked multiple times. In this way, when manufacturing a chip-embedded type semiconductor device (FOD [Film on Die] type semiconductor device), the die bond sheet 10 may be used to embed the semiconductor chip.

[0130] 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 10 and promote the hardening of the die bond sheet 10.

[0131] 8, in the wire bonding process, a semiconductor chip X (die) and an adherend Z are connected with a wire L while being heated. Therefore, the crosslinkable group in the above-mentioned crosslinkable group-containing acrylic polymer contained in the die bond sheet 10 becomes reactive again by heating, and the curing reaction of the die bond sheet 10 can proceed. In the wire bonding step, a compressive force may be applied to the die bond sheet 10 in the thickness direction.

[0132] 9, the semiconductor chip X (die) and the die bond sheet 10 are sealed with a thermosetting resin M such as epoxy resin. In the sealing process, a heat treatment is performed at a temperature of 100° C. or higher and 180° C. or lower to promote the curing reaction of the thermosetting resin M.

[0133] 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). An electronic circuit is formed on one surface of such a thin semiconductor chip. If an electronic circuit is formed on one surface of the thin semiconductor chip, the semiconductor chip may not be able to withstand the internal stress and may deform slightly (e.g., warp), and this deformation may also cause warping of the die bond sheet (see Figure 10). In the expanding process described above, particularly in the room temperature expanding process, the dicing tape 20 is stretched with a strong force in the surface direction, so if the chip is warped, the dicing tape 20 and the die bond sheet 10 will peel off, causing the so-called chip lifting phenomenon. In order to prevent this chip lifting, a relatively high adhesive strength is required between the dicing tape 20 and the die bond sheet 10 in the expanding process. On the other hand, in the pick-up step, it is required that the die bond sheet 10 can be easily peeled off from the dicing tape 20 (good pick-up properties). In order to achieve these contradictory performances, for example, the dicing tape 20 is designed so that the adhesive layer 22 of the dicing tape 20 can be cured by irradiation with active energy rays. Specifically, the low-temperature expanding step for cleaving in the expanding step and the room-temperature expanding step for ensuring the chip-to-chip distance are performed in a state in which the adhesive layer 22 has a relatively high adhesive strength before being irradiated with active energy rays. On the other hand, the adhesive layer 22 is irradiated with active energy rays before the pick-up step to reduce the adhesive strength of the adhesive layer 22. In this embodiment, the acrylic copolymer contained in the pressure-sensitive adhesive layer 22 contains a predetermined mole percentage of hydroxy group-containing (meth)acrylate units as crosslinkable group-containing (meth)acrylate units. In this way, the pressure-sensitive adhesive layer 22 is designed so that the polarity of the pressure-sensitive adhesive layer 22 before curing is appropriately high. This allows the adhesive strength between the pressure-sensitive adhesive layer 22 before curing and the die bond sheet 10 to be appropriately increased, and the pressure-sensitive adhesive layer 22 before curing and the die bond sheet 10 to be adhered relatively strongly together. Furthermore, when the crosslinkable group-containing (meth)acrylate units have a radically polymerizable carbon-carbon double bond, the die bond sheet 10 can be more easily peeled from the pressure-sensitive adhesive layer 22 after curing, and better pick-up properties are exhibited. Furthermore, in this embodiment, the acrylic copolymer contained in the pressure-sensitive adhesive layer 22 contains a predetermined mole percent of aliphatic acrylic (meth)acrylate units. As a result, the pressure-sensitive adhesive layer 22 is designed so that the polarity of the pressure-sensitive adhesive layer 22 after curing by active energy rays is low. This makes it possible to weaken the adhesion between the pressure-sensitive adhesive layer 22 and the die bond sheet 10 after irradiation with active energy rays, and the pressure-sensitive adhesive layer 22 after curing has improved releasability from the die bond sheet 10. In this way, in this embodiment, the pressure-sensitive adhesive layer 22 after curing by irradiation with active energy rays has a relatively low polarity, and therefore the interfacial interaction with the die bond sheet 10, which has a relatively high polarity, is small. Therefore, the die bond sheet 10 is easily peeled from the pressure-sensitive adhesive layer 22 after curing.

[0134] 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.

[0135] The matters disclosed by this specification include the following. (1) An adhesive tape used in the adhesive layer of a dicing die bond film having an adhesive layer and a die bond sheet superimposed on the adhesive layer, The pressure-sensitive adhesive tape contains an acrylic copolymer having, as monomer units, at least an aliphatic alkyl (meth)acrylate unit in the alkyl moiety of which carbon number is 12 or more and a crosslinkable group-containing (meth)acrylate unit in the molecule; The acrylic copolymer contains 10 mol % or more and 85 mol % or less of the aliphatic alkyl (meth)acrylate unit and 15 mol % or more and 35 mol % or less of the crosslinkable group-containing (meth)acrylate unit. (2) The pressure-sensitive adhesive tape according to (1) above, wherein a part of the crosslinkable group-containing (meth)acrylate units in the acrylic copolymer has a radically polymerizable carbon-carbon double bond. (3) The pressure-sensitive adhesive tape according to (2) above, wherein the acrylic copolymer contains the crosslinkable group-containing (meth)acrylate unit having the radically polymerizable carbon-carbon double bond in an amount of 8 mol % or more and 31 mol % or less of all monomer units. (4) The pressure-sensitive adhesive tape according to any one of (1) to (3) above, wherein in the acrylic copolymer, the proportion of the aliphatic alkyl (meth)acrylate units in all monomer units is 15 mol % or more and 40 mol % or less. (5) The pressure-sensitive adhesive tape according to any one of (1) to (4) above, which has a phase-separated structure when a cross section thereof is observed with an electron microscope. (6) the acrylic copolymer contains, as the crosslinkable group-containing (meth)acrylate unit, a hydroxy group-containing (meth)acrylate unit and a polymerizable (meth)acrylate unit having a radical polymerizable carbon-carbon double bond (polymerizable unsaturated double bond); The pressure-sensitive adhesive tape according to any one of (1) to (5) above, wherein the acrylic copolymer further contains, as the alkyl (meth)acrylate units, saturated branched alkyl (meth)acrylate units having an alkyl moiety with 8 to 10 carbon atoms and saturated linear aliphatic alkyl (meth)acrylate units having an alkyl moiety with 12 to 14 carbon atoms. (7) The pressure-sensitive adhesive tape according to (6) above, wherein in the acrylic copolymer, the content of the polymerizable (meth)acrylate units is lower than the content of both the saturated branched alkyl (meth)acrylate units and the saturated linear aliphatic alkyl (meth)acrylate units. (8) The acrylic copolymer contains, as the alkyl(meth)acrylate units, saturated branched alkyl(meth)acrylate units having an alkyl moiety with 7 to 11 carbon atoms and saturated linear aliphatic alkyl(meth)acrylate units having an alkyl moiety with 12 to 14 carbon atoms, The pressure-sensitive adhesive tape according to any one of (1) to (7) above, wherein in the acrylic copolymer, the ratio of the saturated branched alkyl (meth)acrylate units to the saturated linear aliphatic alkyl (meth)acrylate units in terms of moles is 1.0 or more and 5.0 or less. (9) A dicing tape having a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive tape according to any one of (1) to (8) above and a base layer superposed on the pressure-sensitive adhesive layer; A dicing die bond film comprising: a die bond sheet superimposed on the pressure-sensitive adhesive layer of the dicing tape. (10) The dicing die bond film described in (9) above, wherein the peel strength between the pressure-sensitive adhesive layer and the die bond sheet is such that the peel strength (A) before the pressure-sensitive adhesive layer is cured by active energy rays and the peel strength (B) after curing satisfy the following formula (1): (A) / (B)>7.0 Equation (1) (11) The dicing die bond film according to (10) above, wherein the (A) / (B) ratio satisfies the following formula (2): (A) / (B)>8.0 Formula (2) (12) A method for manufacturing a semiconductor device, comprising: a cutting step of cutting the wafer (pattern wafer) on which the circuit surface is formed into chips; A method for manufacturing a semiconductor device, comprising a pickup step of peeling the die bond sheet attached to the adhesive tape of the dicing die bond film described in either (9) or (11) above from the adhesive tape together with the chip. [Example]

[0136] 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.

[0137] A dicing tape was produced as follows: The dicing tape was bonded to a die bond sheet to produce a dicing die bond film.

[0138] <Creating dicing tape> (raw material monomer for acrylic copolymer) 2-Hydroxyethyl acrylate (HEA) 2-Hydroxyethyl methacrylate (HEMA) 4-Hydroxybutyl acrylate (4HBA) Ethyl acrylate (EA) 2-Ethylhexyl acrylate (2EHA) Isononyl acrylate (INA) Lauryl acrylate (LA) Acryloylmorpholine (ACMO) (Examples 1 to 8) / (Comparative Examples 1 to 4) The raw materials were placed in a reaction vessel equipped with a condenser, nitrogen inlet, thermometer, and stirrer, so as to obtain the composition shown in Table 1. For a total of 100 parts by mass of monomers, 0.2 parts by weight of azobisisobutyronitrile (AIBN) was used as a thermal polymerization initiator. Ethyl acetate was added as a reaction solvent so that the total monomer concentration reached a predetermined concentration (e.g., 35% by mass). The polymerization reaction was carried out in a nitrogen stream at 62°C for a predetermined time (e.g., 6 hours), and then at 75°C for a predetermined time (e.g., 2 hours), to obtain an acrylic copolymer intermediate. In each example and comparative example, the monomer concentration during polymerization and the polymerization time are as shown in Table 2.

[0139] To the liquid containing the acrylic copolymer intermediate prepared as described above, 2-methacryloyloxyethyl isocyanate (hereinafter also referred to as MOI) was added in the molar ratio shown in Table 1 (represented as polymerizable group-containing monomer units in Table 1) relative to the total amount of monomers blended during polymerization. For example, in Example 1, MOI was added so that the MOI was 14 moles relative to a total of 100 moles of monomers blended during polymerization. Furthermore, 0.5 mass% of dibutyltin dilaurate was added as a reaction catalyst relative to the amount of MOI added. Subsequently, an addition reaction (urethanization reaction) was carried out in an air stream at 50°C for 12 hours to obtain an acrylic copolymer. Next, the following ingredients were added to 100 parts by mass of the acrylic copolymer to prepare a pressure-sensitive adhesive solution. Photopolymerization initiator: 3 parts by weight per 100 parts by weight of acrylic copolymer intermediate (Product name: Omnirad127D, manufactured by IGM) Polyisocyanate compound: 0.8 parts by mass per 100 parts by mass of acrylic copolymer intermediate (Product name: Coronate L, manufactured by Tosoh Corporation) Antioxidant: 0.01 parts by weight per 100 parts by weight of acrylic copolymer intermediate (Product name: Irganox1010, manufactured by BASF Japan) The adhesive solution prepared as described above was applied to the treated surface of a silicone-treated PET release liner and dried by heating at 120° C. for 2 minutes to form an adhesive layer with a thickness of 10 μm. Subsequently, the adhesive layer and a base layer (polyolefin film (125 μm thick), manufactured by Gunze Ltd., product name "Fanclea NED#125") were bonded together and stored at 50° C. for 24 hours to produce a dicing tape.

[0140] <Production of die bond sheet> Acrylic polymer: 100 parts by weight (Product name "PARACRON KG-8001", mass average molecular weight: 1,200,000, glass transition temperature Tg: 9℃, contains epoxy group, manufactured by Negami Kogyo Co., Ltd.) Phenolic resin: 3 parts by weight (Product name: MEHC-7851SS, solid at 23°C, manufactured by Meiwa Kasei Co., Ltd.) Silica filler: 10 parts by weight (Product name: SE2050-MCV, average particle size 500 nm, manufactured by Admatechs Co., Ltd.) The above raw materials were added to a predetermined amount of methyl ethyl ketone and mixed to prepare an adhesive composition solution with a total solids concentration of 12% by mass. Next, the adhesive composition was applied using an applicator to the silicone release-treated surface of a PET release liner (separator) having a silicone release-treated surface to form a coating film. This coating film was then heated and dried at 130°C for 2 minutes to produce a 10 μm thick die-bonding sheet on the PET release liner (separator).

[0141] <Dicing die bond film manufacturing> The die bond sheet was punched into a circle with a diameter of 330 mm to prepare a circular die bond sheet. At room temperature, the circular die bond sheet and dicing tape were bonded together using a laminator to produce a dicing die bond film.

[0142] <Observation of phase separation structure inside the adhesive layer> Two adhesive layers were prepared and bonded together. Then, the adhesive layer was thinned to a thickness of approximately 100 nm using an ultramicrotome in a frozen atmosphere (-100°C). The above-mentioned ultrathin sectioning method was performed on a cross section of the adhesive layer cut in the thickness direction. Next, the thin film samples were stained with heavy metals (OsO4 and RuO4), and the stained thin film samples were observed by TEM and photographed. Furthermore, the observed photographs were analyzed to calculate the area percentage of the first phase (the phase with a higher content of polymerizable double bonds and darker due to the staining). If there were any gray areas, the total area of ​​both the black and gray areas was considered to be the area of ​​the first phase. [Transmission electron microscope (TEM) observation conditions] Equipment: Hitachi,HT7820 Accelerating voltage: 100 kV [Area ratio calculation method] Image analysis software: Product name "ImageJ" Photo magnification: Observation magnification 12,000x Area analyzed in observed image: 13 μm 2 When the pressure-sensitive adhesive layers were observed as described above, it was confirmed that at least the pressure-sensitive adhesive layers of the Examples had a phase-separated structure as shown in FIGS.

[0143] <Measurement of physical properties of dicing die bond film> The physical properties of the dicing die bond films of each of the Examples and Comparative Examples were measured as follows.

[0144] [Peel strength (adhesive strength) between adhesive layer and die bond sheet] Details of the method for measuring the peel strength (adhesive strength) before UV irradiation (before curing) and after UV irradiation (after curing) are as follows. The measurement results are shown in Table 1. Table 1 also shows the ratio of the peel strength (adhesive strength) before curing to the peel strength (adhesive strength) after curing.

[0145] [Peel strength between adhesive layer and die bond sheet (after UV irradiation)] The peel strength was measured by a T-peel test. Measurement samples were prepared as follows. The PET release liner (separator) was peeled off from the die bond sheet to expose one side of the die bond sheet. A backing tape (product name "ELP BT315" manufactured by Nitto Denko Corporation) was attached to the exposed side. A high-pressure mercury lamp (product name "UM-810" 60 mW / cm manufactured by Nitto Seiki Co., Ltd.) was used. 2 ) from the substrate layer side with an intensity of 150 mJ / cm 2 The adhesive layer was cured by irradiating it with ultraviolet light. Thereafter, a measurement sample measuring 50 mm in width and 120 mm in length was cut out from the adhesive layer. A T-peel test was carried out on the prepared measurement sample using a tensile tester (e.g., product name "AUTOGRAPH AGX-V" manufactured by Shimadzu Corporation). The test conditions were a temperature of 25°C and a tensile speed of 300 mm / min.

[0146] [Peel strength between adhesive layer and die bond sheet (before UV irradiation)] The peel strength was measured in the same manner as above, except that the measurement was performed on the adhesive layer before curing and not exposed to ultraviolet light, and that the adhesive layer was cut out to have dimensions of 20 mm wide x 120 mm long.

[0147] The composition and physical properties of the die bond sheets in each example and each comparative example are shown in Table 1. In Table 1, the mol % of "OH group-containing monomer unit" and the mol % of "polymerizable group-containing monomer unit" indicate the mol % of the hydroxy group-containing (meth)acrylate unit and the mol % of the polymerizable (meth)acrylate unit in the acrylic copolymer, respectively. Note that, since the isocyanate group of the above MOI and the hydroxy group of the hydroxy group-containing (meth)acrylate unit undergo a urethane-forming reaction with nearly 100% reaction efficiency, the above mol % can be calculated based on the blend amounts when the acrylic copolymer is synthesized.

[0148] [Table 1]

[0149] [Table 2]

[0150] The performance of the dicing die bond film produced as described above was evaluated as follows.

[0151] <Performance evaluation (pickup ability through pickup test)> The pick-up property of the semiconductor chip with the die bond sheet in the cleaved state was evaluated. The semiconductor chip with the die bond sheet in the cleaved state was obtained as follows. Specifically, a back-grinding tape was attached to the surface of a 12-inch bare wafer (diameter 300 mm, thickness 55 μm) on which a dividing groove (10 mm × 10 mm) was formed by half-cutting. Then, using a back-grinder (manufactured by DISCO, model DGP8760), the surface of the 12-inch bare wafer (the surface opposite to the side on which the back-grinding tape was attached) was ground to a depth of 25 μm. This resulted in a back-grounded bare wafer. A die-bonding sheet of the dicing die-bonding film of each example was attached to the side of the back-grounded bare wafer opposite to the surface on which the back-grinding tape was attached. In this way, a bare wafer with a dicing die-bonding film was obtained. This bare wafer with a dicing die-bonding film was cleaved by an expanding process. The expanding step was carried out using a die separator (trade name "Die Separator DDS2300, manufactured by Disco Corporation") with the backgrind tape peeled off from the bare wafer. In the expanding step, cool expansion was carried out, followed by room temperature expansion. The cool expansion was carried out as follows. Specifically, a 12-inch diameter SUS ring frame (manufactured by Disco Corporation) was attached at room temperature to the frame attachment area on the adhesive layer of the dicing die bond film attached to the bare wafer. Thereafter, the bare wafer with the SUS ring frame attached was loaded into a die separator. Cool expansion was carried out by expanding the dicing tape of the dicing die bond film using the cool expander unit of the die separator. The conditions at this time were an expansion temperature of -15°C, an expansion speed of 100 mm / sec, and an expansion amount of 7 mm. After the cool expansion, the semiconductor wafer was singulated (individualized) into multiple semiconductor chips. The die bond sheet was also singulated into pieces of a size corresponding to the semiconductor chips. Thus, multiple semiconductor chips with die bond sheets were obtained. Cold expansion was performed after cool expansion as follows. The cold expansion was performed by expanding the dicing tape of the dicing die bond film using the cold expansion unit of the die separator device described above. The conditions were an expansion temperature of 23±2°C, an expansion speed of 1 mm / sec, and an expansion amount of 10 mm. The dicing tape after cold expansion was subjected to a heat shrinkage treatment at a temperature of 200°C for 20 seconds. After the dicing tape was heat-shrunk, a pickup test was carried out on the individualized semiconductor chips with the die bond sheet using a device with a pickup mechanism (product name "Die Bonder SPA-300", manufactured by Shinkawa Co., Ltd.). In this pickup test, the push-up speed of the pin member was set to 1 mm / sec, and the push-up amount was set to 2000 μm. The pickup test was carried out after the adhesive layer was cured. The curing treatment was carried out using an ultraviolet irradiation unit (high-pressure mercury lamp, 70 mW / cm) built into the die separator device. 2 ) from the substrate layer side at 1000mJ / cm 2 This was done by irradiating with ultraviolet light. The pick-up test was carried out on five semiconductor chips with die bond sheets. The evaluation criteria for pick-up performance are as follows: ◎(Good): All five semiconductor chips with die bond sheets can be picked up. 〇: (somewhat good) Three or four of the five semiconductor chips with die bond sheets can be picked up. × (bad): Three or more of five semiconductor chips with die bond sheets cannot be picked up.

[0152] <Evaluation of chip retention performance (evaluation of chip lift suppression performance)> A bare wafer ("warped wafer" described in detail below) having a diameter of 300 mm and a dicing ring were attached to the dicing die bond film of each of the Examples and Comparative Examples manufactured as described above while heating at a temperature of 50 to 80°C. Next, the semiconductor wafer and die bond sheet were cleaved using a die separator DDS230 (manufactured by Disco Corporation), and the chip lifting after cleaving was evaluated. The bare wafer was cleaved into bare chips measuring 10 mm in length, 10 mm in width, and 0.055 mm in thickness, and then ground to a thickness of 0.030 mm. As the bare wafer, a "warped wafer" prepared as follows was used in order to make the chip floating phenomenon more likely to occur. [Creating warped wafers] In producing the warped wafer, first, the following components (a) to (f) were dissolved in methyl ethyl ketone to obtain a warpage control composition with a solid content concentration of 20 mass %. (a) Acrylic resin (manufactured by Nagase ChemteX Corporation, product name "SG-70L"): 5 parts by mass (b) Epoxy resin (manufactured by Mitsubishi Chemical Corporation, product name "JER828"): 5 parts by mass (c) Phenolic resin (manufactured by Meiwa Kasei Co., Ltd., product name "LDR8210"): 14 parts by mass (d) Epoxy resin (manufactured by Mitsubishi Chemical Corporation, product name "MEH-8005"): 2 parts by mass (e) Spherical silica (manufactured by Admatechs Co., Ltd., product name "SO-25R"): 53 parts by mass (f) Phosphorus-based catalyst (TPP-K): 1 part by mass Next, the warpage control composition was applied to a thickness of 25 μm on the silicone-treated surface of a PET separator (50 μm thick) serving as a release liner using an applicator. The solvent was removed from the warpage control composition by drying at 130°C for 2 minutes. In this way, a warpage control sheet was obtained in which a warpage control layer was laminated on the release liner. Next, a bare wafer was attached to the side of the warpage adjusting sheet where the release liner was not laminated using a laminator (MCK Corporation, Model MRK-600) under conditions of 60°C, 0.1 MPa, and 10 mm / s. The sheet was then placed in an oven and heated at 175°C for 1 hour to thermally cure the resin in the warpage adjusting layer. As a result, a bare wafer warped due to shrinkage of the warpage adjusting layer was obtained. After shrinking the warpage adjustment layer, a wafer processing tape (manufactured by Nitto Denko Corporation, product name "V-12SR2") was attached to the side of the warped bare wafer where the warpage adjustment layer was not laminated. Then, a dicing ring was fixed to the warped bare wafer via the wafer processing tape. Furthermore, the warpage adjustment layer was removed from the warped bare wafer. Using a dicing machine (manufactured by DISCO, model number 6361), grooves were formed in a grid pattern (groove width 20 μm) to a depth of 100 μm from the surface over the entire surface of the warped bare wafer from which the warpage adjustment layer had been removed (hereinafter referred to as one side). Next, a backgrinding tape was stuck to one surface of the warped bare wafer, and the wafer processing tape was removed from the other surface (the surface opposite to the one surface) of the warped bare wafer. Next, the warped bare wafer was ground from the other side using a back grinder (manufactured by DISCO, model DGP8760) so that the thickness of the warped bare wafer became 30 μm (0.030 mm). The wafer obtained in this manner was used as a warped wafer.

[0153] [Method for evaluating retention (chip lift prevention)] First, the bare wafer and the die bond sheet were cleaved in a cool expander unit under the conditions of an expansion temperature of −15° C., an expansion speed of 200 mm / sec, and an expansion amount of 11 mm to obtain a semiconductor chip with a die bond sheet. Next, an expansion process was carried out under the conditions of room temperature, expansion speed of 1 mm / sec, and expansion amount of 7 mm. Then, while maintaining the expanded state, the dicing die bond film at the boundary with the outer edge of the bare wafer was thermally shrunk under the conditions of a heat temperature of 200°C, an air volume of 40 L / min, a heat distance of 20 mm, and a rotation speed of 3° / sec. Next, with the dicing ring held on the dicing die bond film, the semiconductor chip with the die bond sheet was observed from the dicing tape side (the polyolefin film side as the base layer).Then, the contact rate of the semiconductor chip to the die bond sheet was calculated to evaluate the holding ability. Specifically, a microscope photograph was taken from the dicing tape side using a VHX-6000 (manufactured by Keyence Corporation). The photographed microscope photograph was then analyzed using image analysis software (product name: ImageJ). Furthermore, the area of ​​the portion of the die where the semiconductor chip was not floating above the die bond sheet was measured. The area of ​​the semiconductor chip was also calculated from the size of the semiconductor chip. Then, the contact rate of the semiconductor chip to the die bond sheet was calculated from the area of ​​the semiconductor chip and the area of ​​the portion where the semiconductor chip was not floating. Based on the contact rate value, the retention performance was evaluated according to the following evaluation criteria. ○: Contact rate is 70% or more △: Contact rate is between 60% and 70% ×: Contact rate is less than 60%

[0154] As can be seen from the above evaluation results, the dicing die bond films of the examples were better in terms of pickup properties than the dicing die bond films of the comparative examples.

[0155] The pressure-sensitive adhesive layer (adhesive tape) of the dicing die bond film of the embodiment contains, as a monomer unit, an acrylic copolymer having at least an aliphatic alkyl (meth)acrylate unit having 12 or more carbon atoms in the alkyl portion and a crosslinkable group-containing (meth)acrylate unit in the molecule, The acrylic copolymer contains 10 mol % or more and 85 mol % or less of the aliphatic alkyl (meth)acrylate units, and 15 mol % or more and 35 mol % or less of the crosslinkable group-containing (meth)acrylate units. The crosslinkable group-containing (meth)acrylate unit includes a hydroxy group-containing (meth)acrylate unit in which a hydroxy group is bonded to an alkyl moiety having 4 or less carbon atoms, and a polymerizable (meth)acrylate unit having a radical polymerizable carbon-carbon double bond (polymerizable unsaturated double bond) in the side chain. By using the dicing die bond film of the embodiment having such a configuration in the manufacture of a semiconductor device, the semiconductor device can be manufactured efficiently. In the manufacturing of a semiconductor device, in the expanding process, a relatively high adhesive strength between the pressure-sensitive adhesive layer and the die bond sheet is required to suppress the chip lift phenomenon described above. On the other hand, after the pressure-sensitive adhesive layer is cured by, for example, irradiating the pressure-sensitive adhesive layer with active energy rays such as ultraviolet light before the pick-up process, it is necessary for the die bond sheet to be easily peeled from the cured pressure-sensitive adhesive layer (exhibiting good pick-up properties). To achieve these contradictory properties, the pressure-sensitive adhesive layer contains an acrylic copolymer having aliphatic alkyl (meth)acrylate units, hydroxyl group-containing (meth)acrylate units as crosslinkable group-containing (meth)acrylate units, and polymerizable (meth)acrylate units in the molecule in the above-mentioned mole percentages. When the acrylic copolymer contains crosslinkable group-containing (meth)acrylate units in the above mole percentages, the adhesive strength of the adhesive layer before curing is not reduced too much and is good, and when the acrylic copolymer contains aliphatic alkyl (meth)acrylate units in the above mole percentages, the adhesive strength of the adhesive layer after curing can be reduced appropriately. [Industrial Applicability]

[0156] 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]

[0157] 1: dicing die bond film, 10: Die bond sheet, 20: dicing tape, 21: Base material layer, 22: Adhesive layer (adhesive tape).

Claims

1. A pressure-sensitive adhesive tape used as the pressure-sensitive adhesive layer of a dicing die-bonding film comprising a pressure-sensitive adhesive layer and a die-bonding sheet superimposed on the pressure-sensitive adhesive layer, The pressure-sensitive adhesive tape contains an acrylic copolymer having, as monomer units, at least an aliphatic alkyl (meth)acrylate unit in the alkyl moiety of which carbon number is 12 or more and a crosslinkable group-containing (meth)acrylate unit in the molecule; the acrylic copolymer contains 10 mol % or more and 85 mol % or less of the aliphatic alkyl (meth)acrylate unit and 15 mol % or more and 35 mol % or less of the crosslinkable group-containing (meth)acrylate unit, An adhesive tape having a phase separation structure when its cross section is observed under an electron microscope.

2. A pressure-sensitive adhesive tape used as the pressure-sensitive adhesive layer of a dicing die-bonding film comprising a pressure-sensitive adhesive layer and a die-bonding sheet superimposed on the pressure-sensitive adhesive layer, The pressure-sensitive adhesive tape contains an acrylic copolymer having, as monomer units, at least an aliphatic alkyl (meth)acrylate unit having 12 or more carbon atoms in the alkyl moiety, an isononyl (meth)acrylate unit as a saturated branched alkyl (meth)acrylate unit having 7 to 11 carbon atoms in the alkyl moiety, and a crosslinkable group-containing (meth)acrylate unit in the molecule; the acrylic copolymer contains 10 mol % or more and 80 mol % or less of the aliphatic alkyl (meth)acrylate unit and 15 mol % or more and 35 mol % or less of the crosslinkable group-containing (meth)acrylate unit.

3. The pressure-sensitive adhesive tape according to claim 1 or 2, wherein a part of the crosslinkable group-containing (meth)acrylate units in the acrylic copolymer has a radically polymerizable carbon-carbon double bond.

4. The pressure-sensitive adhesive tape according to claim 3, wherein the acrylic copolymer contains the crosslinkable group-containing (meth)acrylate unit having the radical polymerizable carbon-carbon double bond in an amount of 8 mol % or more and 31 mol % or less of the monomer units.

5. The pressure-sensitive adhesive tape according to claim 1 , wherein in the acrylic copolymer, the proportion of the aliphatic alkyl (meth)acrylate units in the monomer units is 15 mol % or more and 40 mol % or less.

6. The pressure-sensitive adhesive tape according to claim 2 , which has a phase-separated structure when a cross section thereof is observed with an electron microscope.

7. A dicing tape having a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive tape according to any one of claims 1 to 6 and a base layer superposed on the pressure-sensitive adhesive layer; A dicing die bond film comprising: a die bond sheet superimposed on the pressure-sensitive adhesive layer of the dicing tape.

8. 8. The dicing die bond film according to claim 7, wherein the peel force between the pressure-sensitive adhesive layer and the die bond sheet is such that the peel force (A) before the pressure-sensitive adhesive layer is cured by active energy rays and the peel force (B) after the pressure-sensitive adhesive layer is cured satisfy the following formula (1): (A) / (B)>7.0 Formula (1)

9. The dicing die bond film according to claim 8, wherein the (A) / (B) satisfies the following formula (2): (A) / (B)>8.0 Formula (2)

10. A method for manufacturing a semiconductor device, comprising: a cutting step of cutting the wafer on which the circuit surface is formed into chips; A method for manufacturing a semiconductor device, comprising: a pick-up step of peeling off the die bond sheet attached to the adhesive tape of the dicing die bond film according to any one of claims 7 to 9 from the adhesive tape together with the chip.

Images