Dicing die bond film

Abstract

To provide a dicing die-bonding film exhibiting chip float suppression performance and excellent pickup performance.SOLUTION: There is provided a dicing die-bonding film including a dicing tape having an adhesive base material layer and an adhesive layer overlaid on the base material layer, and a die-bonding sheet overlaid on the dicing tape. The adhesive layer has a phase separation structure when a cross section of the adhesive layer is observed with an electron microscope. The phase separation structure includes a first phase containing a radical polymerizable carbon-carbon double bond, and a second phase separated from the first phase, the second phase having a content of the radical polymerizable carbon-carbon double bond lower than that of the first phase, the area ratio of the first phase in the cross section being higher than 50%.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a dicing die bond film used, for example, in the manufacture of semiconductor devices. [Background technology]

[0002] Conventionally, dicing die bond films used in the manufacture of semiconductor devices are known. This type of dicing die bond film comprises, 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 substrate layer and an adhesive layer in contact with the die bond sheet. This type of dicing die bond film is used in the manufacture of semiconductor devices, for example, as described below.

[0003] A method for manufacturing semiconductor devices generally comprises a front-end process in which a circuit surface is formed on one side of a wafer using highly integrated electronic circuits, and a back-end process in which chips are cut out from the wafer with the circuit surface formed on it and assembled.

[0004] The subsequent processes include, for example, a dicing process to form a fragile area on the wafer for cleaving it into smaller chips (dies); a mounting process to fix the wafer to the dicing tape by attaching the side of the wafer opposite to the circuit surface to a die bond sheet; an expanding process to widen the spacing between chips by cleaving the wafer with the fragile area formed together with the die bond sheet; a pick-up process to remove the chips (dies) with the die bond sheet attached by peeling them apart from the adhesive layer; a die bonding process to adhere the chips (dies) with the die bond sheet attached to a substrate via the die bond sheet; and a curing process to heat-set the die bond sheet that has been adhered to the substrate. Semiconductor devices are manufactured, for example, through these processes.

[0005] In the semiconductor device manufacturing method described above, for example, in the pickup step described above, 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 peelability when peeling 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 by 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 relatively easily together with the die bond sheet. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2009-135377 [Overview of the project] [Problems that the invention aims to solve]

[0008] For example, in the expansion process described above, the dicing tape is stretched with strong force in the planar direction to cleave the wafer and widen the gaps between chips. At this time, even when the dicing tape is stretched, it is required that the adhesive layer of the dicing tape and the die bond sheet attached to the chips maintain a relatively strong adhesive force without peeling apart. In other words, it is required that the so-called chip lifting phenomenon, where the die bond sheet peels away from the adhesive layer, be suppressed. On the other hand, in the pickup process, it is required that the adhesive layer of the dicing tape and the die bond sheet peel apart relatively easily. In other words, it is required that good pickup performance be exhibited. Thus, the dicing die bond film is required to have two conflicting properties: the ability to suppress chip lifting and good pickup performance.

[0009] However, dicing die bond films that possess both chip lifting suppression performance and good pickup properties have not yet been sufficiently investigated.

[0010] Therefore, the object of the present invention is to provide a dicing die bond film that has chip lifting suppression performance and good pick-up properties. [Means for solving the problem]

[0011] To solve the above problems, the dicing die bond film according to the present invention comprises a dicing tape having a base layer and an adhesive layer superimposed on the base layer, and a die bond sheet superimposed on the dicing tape. The adhesive layer, when observed in cross-section with an electron microscope, has a phase-separated structure. The phase separation structure comprises a first phase containing radically polymerizable carbon-carbon double bonds and a second phase having a lower content of radically polymerizable carbon-carbon double bonds than the first phase and being separated from the first phase. The area ratio of the first phase in the cross-section is higher than 50%. [Effects of the Invention]

[0012] According to the dicing die bonding film according to the present invention, it is possible to exhibit the performance of suppressing chip floating and good pick-up property.

Brief Description of the Drawings

[0013] [Figure 1] Cross-sectional view of the dicing die bonding film of the present embodiment cut in the thickness direction. [Figure 2A] Cross-sectional view schematically showing the state of the stealth dicing process in the method for manufacturing a semiconductor device. [Figure 2B] Cross-sectional view schematically showing the state of the stealth dicing process in the method for manufacturing a semiconductor device. [Figure 2C] Cross-sectional view schematically showing the state of the stealth dicing process in the method for manufacturing a semiconductor device. [Figure 2D] Cross-sectional view schematically showing the state of the back grinding process in the method for manufacturing a semiconductor device. [Figure 3A] Cross-sectional view schematically showing the state of the mounting process in the method for manufacturing a semiconductor device. [Figure 3B] Cross-sectional view schematically showing the state of the mounting process in the method for manufacturing a semiconductor device. [Figure 4A] Cross-sectional view schematically showing the state of the expansion process at low temperature in the method for manufacturing a semiconductor device. [Figure 4B] Cross-sectional view schematically showing the state of the expansion process at low temperature in the method for manufacturing a semiconductor device. [Figure 4C] Cross-sectional view schematically showing the state of the expansion process at low temperature in the method for manufacturing a semiconductor device. [Figure 5A] Cross-sectional view schematically showing the state of the expansion process at room temperature in the method for manufacturing a semiconductor device. [Figure 5B] Cross-sectional view schematically showing the state of the expansion process at room temperature in the method for manufacturing a semiconductor device. [Figure 6] Cross-sectional view schematically showing the state of the pick-up process in the method for manufacturing a semiconductor device. [Figure 7] A schematic cross-sectional view illustrating the die bonding process in the manufacturing of semiconductor devices. [Figure 8] A schematic cross-sectional view illustrating the wire bonding process in the manufacturing of semiconductor devices. [Figure 9] A schematic cross-sectional view illustrating the encapsulation process in the manufacturing method of semiconductor devices. [Figure 10] A schematic cross-sectional view illustrating an example of a warped semiconductor chip and die bond sheet. [Figure 11] An example of an image observed when observing a cross-section of an adhesive layer with an electron microscope (the left side is a schematic diagram, and the right side is a photograph). [Figure 12] Other examples of images observed when observing a cross-section of an adhesive layer with an electron microscope (schematic diagram on the left, photograph on the right). [Modes for carrying out the invention]

[0014] Hereinafter, one embodiment of the dicing die bond film according to the present invention will be described with reference to the drawings. Note that the figures in the drawings are schematic diagrams and do not necessarily have the same aspect ratio as the actual product.

[0015] As shown in Figure 1, the dicing die bond film 1 of this embodiment comprises a dicing tape 20 and a die bond sheet 10 which is laminated on the adhesive layer 22 (described later) of the dicing tape 20 and adhered to a semiconductor wafer.

[0016] In the dicing die bond film 1 of this embodiment, the adhesive layer 22 is cured when exposed to active energy rays (e.g., ultraviolet light) during use. Specifically, a die bond sheet 10 with a semiconductor wafer bonded to one side and an adhesive layer 22 bonded to the other side of the die bond sheet 10 are laminated together, and ultraviolet light or the like is irradiated onto at least the adhesive layer 22. For example, ultraviolet light or the like is irradiated from the side where the base layer 21 is located, and the ultraviolet light or the like passes through the base layer 21 and reaches the adhesive layer 22. The adhesive layer 22 is cured by the irradiation of ultraviolet light or the like. Since the adhesive layer 22 hardens after irradiation, its adhesive strength can be reduced, making it relatively easy to peel the die bond sheet 10 (with the semiconductor wafer attached) from the adhesive layer 22 after irradiation. The die bond sheet 10 is bonded to an adherend such as a circuit board or semiconductor chip in the manufacturing of semiconductor devices.

[0017] <Dicing tape for dicing die bond film> The dicing tape 20 described above is typically a long sheet and is stored wound up until use. The dicing die bond film 1 of this embodiment is stretched over an annular frame having an inner diameter slightly larger than the silicon wafer to be diced, and then cut for use.

[0018] The dicing tape 20 described above comprises a base layer 21 and an adhesive layer 22 superimposed on the base layer 21.

[0019] In this embodiment, the adhesive layer 22 includes, for example, an acrylic polymer having at least one monomer unit (meth)acrylate unit, which is polymerized from (meth)acrylic acid ester monomers, in its molecule, an isocyanate compound, and a polymerization initiator. The adhesive layer 22 may have a thickness of 5 μm or more and 40 μm or less. The shape and size of the adhesive layer 22 are usually the same as those of the base layer 21.

[0020] In this embodiment, the acrylic polymer contained in the adhesive layer 22 has, as monomer units, at least a crosslinkable group-containing (meth)acrylate unit having a crosslinkable group that undergoes a crosslinking reaction by curing treatment, and a long-chain alkyl (meth)acrylate unit with 8 or more carbon atoms in the alkyl portion in its molecule. Monomer units are units that constitute the main chain of the acrylic polymer. In other words, monomer units are derived from monomers used to polymerize the acrylic copolymer. Each side chain in the above acrylic polymer is contained in each monomer unit that constitutes the main chain. 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."

[0021] In the following explanation, we will refer to acrylic polymers as acrylic copolymers, in order to provide a detailed explanation of cases where acrylic polymers are copolymers.

[0022] In this embodiment, the above-mentioned crosslinkable group-containing (meth)acrylate unit has at least one polymerizable (meth)acrylate unit containing a radical polymerizable carbon-carbon double bond and a hydroxyl group-containing (meth)acrylate unit in which a hydroxyl group is bonded to an alkyl portion having 4 or fewer carbon atoms. Furthermore, in this embodiment, the polymerizable (meth)acrylate unit is a monomer unit derived from a hydroxyl group-containing (meth)acrylate unit. For example, during the preparation of an acrylic copolymer, the polymerizable (meth)acrylate unit can be produced by urethane reaction between a hydroxyl group in a portion of the hydroxyl group-containing (meth)acrylate unit and the isocyanate group of an isocyanate group-containing polymerizable (meth)acrylate monomer.

[0023] The long-chain alkyl (meth)acrylate units contained in the molecule of the above-mentioned acrylic copolymer include aliphatic alkyl (meth)acrylate units with 12 or more carbon atoms in the alkyl portion.

[0024] The adhesive layer 22 has a phase separation structure when its cross-section is observed with an electron microscope. More specifically, the phase separation structure has a first phase containing radically polymerizable carbon-carbon double bonds and a second phase that is separated from the first phase and has a lower content of radically polymerizable carbon-carbon double bonds than the first phase. In other words, the content of radically polymerizable carbon-carbon double bonds in the first phase is higher than the content of radically polymerizable carbon-carbon double bonds in the second phase. When the cross-section of the adhesive layer 22 is observed with an electron microscope, for example, the first phase is shown in a darker color and the second phase is shown in a lighter color.

[0025] The above phase separation structure may also be a sea-island structure in which the first phase is dispersed within a continuous second phase, as shown in Figure 11, for example. Alternatively, the above phase separation structure may also be a co-continuous phase separation structure in which the first and second phases are continuous phases, as shown in Figure 12, for example. Specifically, when staining a sample with OsO4 during electron microscopy observation, osmium reacts with unsaturated bonds (double bonds), and the reacted areas appear more intensely. Therefore, for example, the first phase becomes darker, and contrast can be obtained in the observed image.

[0026] When the cross-section of the adhesive layer 22 is observed with an electron microscope under the following measurement conditions, the area ratio occupied by the first phase is preferably 52% or more, and more preferably 60% or more. Such an area ratio may be 100% or less, 90% or less, 80% or less, or 70% or less. (Measurement conditions) • Method for preparing measurement samples from the adhesive layer: Ultrathin sectioning method using an ultramicrotome • Magnification: 12,000x • Observation area: at least 9 μm 2 (For example, a square with dimensions of 3 μm on each side) • Staining method for measurement samples: OsO4 and RuO4 • Method for calculating area ratio: Image analysis using the product "ImageJ" Furthermore, in the observation image of the measurement sample prepared through the staining treatment described above, areas that appear black and areas that appear gray may coexist due to the influence of the content of unsaturated bonds (double bonds) in the adhesive layer 22. In this case, both the areas that appear black and the areas that appear gray are considered to be the first phase. In other words, the area with the lowest content of unsaturated bonds (double bonds) is the second phase, and the rest is the first phase.

[0027] As described above, the adhesive layer 22 has a first phase with a higher content of radically polymerizable carbon-carbon double bonds and a second phase with a lower content of radically polymerizable carbon-carbon double bonds. Furthermore, as can be seen from the electron microscope image of the cross-section of the adhesive layer 22, the proportion of the first phase is relatively high. The first phase contains a relatively large amount of highly polar radically polymerizable carbon-carbon double bonds, and therefore can be said to be more polar than the second phase. Thus, the adhesive layer 22, which contains a relatively large amount of the highly polar first phase, is highly polar and has a high interaction with the die bond sheet 10. Therefore, before the above double bonds become single bonds through polymerization, the adhesive strength between the adhesive layer 22 and the die bond sheet 10 is kept relatively high. On the other hand, when the adhesive layer 22 is subjected to curing treatment by irradiation with ultraviolet light or the like (described in detail later), the above double bonds become single bonds through polymerization. After the above double bonds become single bonds, the first phase shrinks, and the polarity of the first phase decreases. Therefore, after the adhesive layer 22 has cured, the interaction between the adhesive layer 22 and the die bond sheet 10 decreases, and the adhesive strength between the adhesive layer 22 and the die bond sheet 10 decreases. Thus, in this embodiment, the dicing die bond film 1 can maintain a relatively high adhesive strength between the adhesive layer 22 and the die bond sheet 10 before the adhesive layer 22 hardens, thereby suppressing chip lifting during the expansion process (described in detail later). Furthermore, after the adhesive layer 22 hardens, the adhesive strength between the adhesive layer 22 and the die bond sheet 10 can be reduced, allowing for good pick-up performance during the pick-up process (described in detail later). Therefore, the dicing die bond film 1 can have both chip lifting suppression performance and good pick-up performance.

[0028] In this embodiment, the acrylic copolymer preferably contains a crosslinkable group-containing (meth)acrylate unit having a radically polymerizable carbon-carbon double bond (polymerizable unsaturated double bond) in its side chain, and a hydroxyl group-containing (meth)acrylate unit in which a hydroxyl group is bonded to an alkyl portion having 4 or fewer carbon atoms.

[0029] The crosslinkable group-containing (meth)acrylate unit may be, for example, the hydroxyl group-containing (meth)acrylate unit described above, or the polymerizable (meth)acrylate unit described above that contains a radically polymerizable carbon-carbon double bond. In this embodiment, the polymerizable (meth)acrylate unit has a molecular structure in which, for example, the isocyanate group of an isocyanate group-containing (meth)acrylic monomer is urethane-bonded to the hydroxyl group in the hydroxyl group-containing (meth)acrylate unit described above.

[0030] The above-mentioned crosslinkable group-containing (meth)acrylate units can be prepared by a urethane reaction after the polymerization reaction of the acrylic copolymer. For example, polymerizable (meth)acrylate units can be obtained by copolymerizing an alkyl (meth)acrylate monomer with a hydroxyl group-containing (meth)acrylic monomer (described later), and then urethane reacting the hydroxyl groups in a portion of the hydroxyl group-containing (meth)acrylate units with the isocyanate groups of the isocyanate group-containing polymerizable (meth)acrylate monomer.

[0031] The above-mentioned isocyanate group-containing (meth)acrylic monomer preferably has one isocyanate group and one (meth)acryloyl group in its molecule. An example of an isocyanate group-containing (meth)acrylic monomer is 2-methacryloyloxyethyl isocyanate.

[0032] The above-mentioned acrylic copolymer contains radically polymerizable carbon-carbon double bonds of crosslinkable group-containing (meth)acrylate units, which allows the adhesive layer 22 to be more thoroughly cured by irradiation with active energy rays (such as ultraviolet light) before the pickup step (described in detail later). For example, irradiation with active energy rays such as ultraviolet light generates radicals from the photopolymerization initiator, and these radicals cause a crosslinking reaction between the acrylic copolymers. This reduces the adhesive strength of the adhesive layer 22 before irradiation to a lower level after irradiation. As a result, the diebond sheet 10 can be easily peeled off the adhesive layer 22. Ultraviolet light, radiation, and electron beams are used as the active energy rays.

[0033] The above acrylic copolymer has hydroxyl group-containing (meth)acrylate units. When the adhesive layer 22 contains an isocyanate compound, the isocyanate group of the isocyanate compound and the hydroxyl group of the hydroxyl group-containing (meth)acrylate unit can react readily. By having an acrylic copolymer containing hydroxyl group-containing (meth)acrylate units and an isocyanate compound coexist in the adhesive layer 22, the adhesive layer 22 can be moderately cured. As a result, the acrylic copolymer can gel sufficiently. Therefore, the adhesive layer 22 can exhibit adhesive properties while maintaining its shape.

[0034] In this embodiment, the hydroxyl group-containing (meth)acrylate unit is a hydroxyl group-containing C2-C4 alkyl (meth)acrylate unit in which an OH group is bonded to an alkyl portion having 2 to 4 carbon atoms. The notation "C2-C4 alkyl" represents the hydrocarbon portion ester-bonded to (meth)acrylic acid and its carbon number. In other words, the hydroxyl group-containing C2-C4 alkyl (meth)acrylic monomer refers to a monomer in which (meth)acrylic acid and an alcohol (usually a dihydric alcohol) having 2 to 4 carbon atoms are ester-bonded. The C2-C4 alkyl hydrocarbon portion is usually a saturated hydrocarbon. For example, the C2-C4 alkyl hydrocarbon portion is a linear saturated hydrocarbon or a branched saturated hydrocarbon. It is preferable that the C2-C4 alkyl hydrocarbon portion does not contain polar groups such as oxygen (O) or nitrogen (N).

[0035] Examples of hydroxyl group-containing C2-C4 alkyl (meth)acrylate units include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxy-n-butyl (meth)acrylate, or hydroxy-iso-butyl (meth)acrylate, which are all units of hydroxybutyl (meth)acrylate. The hydroxyl group (-OH group) may be bonded to the terminal carbon (C) of the hydrocarbon portion, or to a carbon (C) other than the terminal carbon of the hydrocarbon portion.

[0036] In this embodiment, as described above, the acrylic copolymer has long-chain alkyl (meth)acrylate units in the molecule with 8 or more carbon atoms in the alkyl portion.

[0037] The long-chain alkyl (meth)acrylate units described above are derived from long-chain alkyl (meth)acrylate monomers with eight or more carbon atoms in the alkyl portion. In other words, the molecular structure after a polymerization reaction of long-chain alkyl (meth)acrylate monomers is the long-chain alkyl (meth)acrylate unit. The notation "alkyl" represents the hydrocarbon portion esterified to (meth)acrylic acid.

[0038] The alkyl portion (hydrocarbon) in the long-chain alkyl (meth)acrylate unit may be a saturated hydrocarbon or an unsaturated hydrocarbon. The alkyl portion (hydrocarbon) in the long-chain alkyl (meth)acrylate unit may be a linear hydrocarbon, a branched hydrocarbon, or may contain a cyclic structure. The number of carbon atoms in the alkyl portion (hydrocarbon) of the long-chain alkyl (meth)acrylate unit may be 22 or less, 18 or less, or 14 or less.

[0039] It is preferable that the long-chain alkyl (meth)acrylate unit does not contain a benzene ring or any polar groups such as ether bonds (-CH2-O-CH2-), -OH groups, or -COOH groups in the molecule. In the long-chain alkyl (meth)acrylate unit, the alkyl portion may be a saturated linear hydrocarbon or a saturated branched hydrocarbon composed of 8 to 18 carbon atoms, without containing any atoms other than C and H. The above acrylic copolymer can exhibit better pickup properties by containing long-chain alkyl (meth)acrylate units.

[0040] Examples of the structure of the alkyl portion (hydrocarbon portion) of the long-chain alkyl (meth)acrylate unit described above include a saturated linear alkyl structure with 8 or more carbon atoms, or a saturated branched alkyl structure. Specifically, long-chain alkyl (meth)acrylate units having a saturated branched alkyl structure include saturated branched alkyl (meth)acrylate units in which the alkyl portion has 8 to 11 carbon atoms. Furthermore, the alkyl portion (hydrocarbon portion) of the above-mentioned long-chain alkyl (meth)acrylate unit may be in a saturated linear form.

[0041] The structure of the alkyl portion (hydrocarbon portion) of the saturated branched alkyl (meth)acrylate unit described above can be any saturated branched alkyl structure, and may be an iso structure, sec structure, neo structure, or tert structure. Specifically, saturated branched alkyl (meth)acrylate units include isooctyl (meth)acrylate, isononyl (meth)acrylate, isodecyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. Among these, at least one of isononyl (meth)acrylate units and 2-ethylhexyl (meth)acrylate units is preferred because they exhibit good pickability and can suppress so-called tip floating during the expansion process.

[0042] The above acrylic copolymer preferably contains aliphatic saturated alkyl (meth)acrylate units as long-chain alkyl (meth)acrylate units, wherein the alkyl portion has 12 or more carbon atoms. The aliphatic saturated alkyl (meth)acrylate units are preferably aliphatic saturated alkyl (meth)acrylate units in which the alkyl portion is a saturated hydrocarbon, and more preferably aliphatic saturated alkyl (meth)acrylate units in which the alkyl portion is a saturated hydrocarbon and the alkyl portion has 12 to 18 carbon atoms.

[0043] Examples of structures for the alkyl portion (hydrocarbon portion) of the above-mentioned aliphatic alkyl (meth)acrylate unit include saturated linear alkyl structures with 12 or more carbon atoms. Specifically, aliphatic alkyl (meth)acrylate units include lauryl (meth)acrylate, myristyl (meth)acrylate, palmityl (meth)acrylate, stearyl (meth)acrylate, and behenyl (meth)acrylate. Furthermore, the alkyl portion (hydrocarbon portion) of the above-mentioned aliphatic alkyl (meth)acrylate unit may be in a saturated branched chain form. The aliphatic alkyl (meth)acrylate unit may include, for example, isostearyl (meth)acrylate units.

[0044] The above acrylic copolymer may contain one of the long-chain alkyl (meth)acrylate units described above, or it may contain two or more of them. Furthermore, the above acrylic copolymer may contain one of the aliphatic alkyl (meth)acrylate units, or it may contain two or more of them.

[0045] The above acrylic copolymer preferably contains a lauryl (meth)acrylate unit and at least one of a 2-ethylhexyl (meth)acrylate unit and an isononyl (meth)acrylate unit. This allows for better pickup properties.

[0046] In this embodiment, in the above-described acrylic copolymer, the proportion of the above-described crosslinkable group-containing (meth)acrylate units to the total monomer units is preferably 18 mol% to 50 mol%. This further suppresses so-called chip floating and allows for better pickup performance. The proportion of the crosslinkable group-containing (meth)acrylate units to the total monomer units may be 20 mol% or more, or 22 mol% or more. It may also be 45 mol% or less, or 40 mol% or less.

[0047] The above acrylic copolymer contains the above polymerizable (meth)acrylate units as crosslinkable group-containing (meth)acrylate units, and preferably the proportion of the above polymerizable (meth)acrylate units to the total monomer units is 8 mol% to 35 mol%. This further suppresses so-called chip floating and allows for better pickup performance.

[0048] The above acrylic copolymer contains the above hydroxyl group-containing (meth)acrylate units as crosslinkable group-containing (meth)acrylate units, and it is preferable that the proportion of the above hydroxyl group-containing (meth)acrylate units to the total monomer units is 5 mol% or more and 30 mol% or less. This further suppresses so-called chip floating and allows for better pickup performance. The proportion of the above hydroxyl group-containing (meth)acrylate units to the total monomer units may be 10 mol% or more, 12 mol% or more, or 26 mol% or less.

[0049] In the above-mentioned acrylic copolymer, it is preferable that the proportion of long-chain alkyl (meth)acrylate units among the total monomer units is 60 mol% or more and 82 mol% or less. This further suppresses so-called chip floating and allows for better pickup performance. The proportion of long-chain alkyl (meth)acrylate units among the total monomer units may be 65 mol% or more, or 70 mol% or more. It may also be 80 mol% or less, or 78 mol% or less.

[0050] In the above-described acrylic copolymer, the proportion of aliphatic alkyl (meth)acrylate units among the total monomer units is preferably 15 mol% to 40 mol%. This further suppresses so-called chip lifting and allows for better pickup performance. The proportion of aliphatic alkyl (meth)acrylate units among the total monomer units may be 10 mol% or more, or 35 mol% or less.

[0051] In the above-described acrylic copolymer, the molar ratio of long-chain alkyl (meth)acrylate units to crosslinkable group-containing (meth)acrylate units is preferably 1.5 to 3.5. This further suppresses so-called chip floating and allows for better pickup performance. Such a molar ratio may be 1.8 or higher, or 2.0 or higher. It may also be 3.4 or lower, or 3.3 or lower.

[0052] In this embodiment, the acrylic copolymer may contain monomer units other than those described above. For example, it may contain units such as (meth)acryloylmorpholine, N-vinyl-2-pyrrolidone, or acrylonitrile.

[0053] In the acrylic copolymer contained in the adhesive layer 22, each of the above units (each constituent unit) is, 1 H-NMR, 13 This can be confirmed by NMR analysis such as 13C-NMR, pyrolysis GC / MS analysis, and infrared spectroscopy. The molar proportion of the above units in acrylic copolymers is usually calculated from the blending amount (starting amount) when polymerizing the acrylic copolymer.

[0054] In this embodiment, the isocyanate compound that may further be contained in the adhesive layer 22 of the dicing tape 20 has multiple isocyanate groups in its molecule. Having multiple isocyanate groups in its molecule allows the crosslinking reaction between acrylic copolymers in the adhesive layer 22 to proceed. Specifically, the crosslinking reaction mediated by the isocyanate compound can be carried out by reacting one isocyanate group of the isocyanate compound with a hydroxyl group of an acrylic copolymer and the other isocyanate group with a hydroxyl group of another acrylic copolymer. Furthermore, the isocyanate compound may be a compound synthesized via a urethane reaction or the like.

[0055] Examples of isocyanate compounds include diisocyanates such as aliphatic diisocyanates, alicyclic diisocyanates, or aromatic aliphatic diisocyanates.

[0056] Furthermore, examples of isocyanate compounds include polymerized polyisocyanates such as dimers and trimers of diisocyanates, and polymethylene polyphenylene polyisocyanates.

[0057] In addition, examples of isocyanate compounds include polyisocyanates obtained by reacting an excess amount of the above-mentioned isocyanate compound with an active hydrogen-containing compound. Examples of active hydrogen-containing compounds include active hydrogen-containing low molecular weight compounds and active hydrogen-containing high molecular weight compounds. In addition, allophanate-modified polyisocyanates, biuret-modified polyisocyanates, and the like can also be used as isocyanate compounds. The above isocyanate compounds can be used individually or in combination of two or more.

[0058] As the above isocyanate compound, a reaction product of an aromatic diisocyanate and an active hydrogen-containing low molecular weight compound is preferred. Since the reaction rate of the isocyanate group in the reaction product of aromatic diisocyanate is relatively slow, excessive hardening of the adhesive layer 22 containing such a reaction product is suppressed. As the above isocyanate compound, one having three or more isocyanate groups in the molecule is preferred.

[0059] The polymerization initiator contained in the adhesive layer 22 is a compound that can initiate a polymerization reaction in response to applied heat or light energy. The presence of the polymerization initiator in the adhesive layer 22 allows for the promotion of crosslinking reactions between acrylic copolymers when thermal or light energy is applied to the adhesive layer 22. Specifically, it enables the initiation of polymerization reactions between polymerizable groups in acrylic copolymers having polymerizable (meth)acrylate units containing radical polymerizable carbon-carbon double bonds, thereby curing the adhesive layer 22. This reduces the adhesive strength of the adhesive layer 22, allowing for easy peeling of the die bond sheet 10 from the cured adhesive layer 22 during the pick-up process. For example, photopolymerization initiators or thermal polymerization initiators can be used as polymerization initiators. Commonly available commercially produced products can be used as polymerization initiators.

[0060] The adhesive layer 22 may further contain other components in addition to those described above. Examples of other components include tackifiers, plasticizers, fillers, anti-aging agents, antioxidants, UV absorbers, light stabilizers, heat stabilizers, antistatic agents, surfactants, and light release agents. The types and amounts of other components may be appropriately selected depending on the purpose.

[0061] In this embodiment, the surface modulus of the adhesive layer 22 after curing by active energy rays is preferably greater than 30 MPa and less than 400 MPa. This allows for better pickup performance. The above surface modulus may be 20 MPa or more, 35 MPa or more, 350 MPa or less, or 310 MPa or less. The curing treatment conditions for the adhesive layer 22 used to measure the surface modulus will be described later.

[0062] The above surface modulus can be increased, for example, by increasing the proportion of polymerizable (meth)acrylate units that constitute the acrylic copolymer. On the other hand, the above modulus can be decreased by decreasing the proportion of polymerizable (meth)acrylate units that constitute the acrylic copolymer.

[0063] The above surface modulus (tensile modulus) is measured under the following conditions. Curing treatment conditions: High-pressure mercury lamp, 60 mW / cm² 2 , strength 300mJ / cm 2 Irradiating with ultraviolet light Measurement device: Nanoindenter (Hysitron Inc.'s "Triboindenter") Indenter used: Berkovich (triangular pyramid) Measurement method: Single indentation measurement Measurement temperature: room temperature Indentation depth: 1 μm Number of measurements: 10 (average value calculated) In detail, in the dicing die bond film, a sample for measurement is taken from an exposed portion of the adhesive layer 22 where the die bond sheet 10 and the adhesive layer 22 do not overlap (see, for example, Figure 1). Normally, the surface of such an exposed portion is covered with a peelable release sheet (described in detail later). With the release sheet attached, a piece is cut in the thickness direction from the exposed portion. Specifically, a square-shaped piece of adhesive layer and base material layer with sides of approximately 1 cm is cut out in the thickness direction. It is confirmed that the adhesive layer and the release sheet are in good contact. A high-pressure mercury lamp, 60 mW / cm², manufactured by Nitto Seiki Co., Ltd., product name "UM-810", is used. 2 Using ), a strength of 300 mJ / cm² is applied from the substrate layer side. 2 The adhesive layer is cured by irradiating it with ultraviolet light. The cured adhesive layer is fixed to the support, and the release sheet attached to the adhesive layer is peeled off. Then, nanoindentation measurement is performed on the surface of the adhesive layer to which the release sheet was attached.

[0064] In this embodiment, the substrate layer 21 superimposed on the 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 fibrous sheet such as paper or cloth, a rubber sheet, or a resin film. Examples of fiber sheets constituting the base material layer 21 include paper, woven fabric, and nonwoven fabric. Examples of resin film materials include polyolefins such as polyethylene (PE), polypropylene (PP), and ethylene-propylene copolymer; ethylene copolymers such as ethylene-vinyl acetate copolymer (EVA), ionomer resin, ethylene-(meth)acrylic acid copolymer, and ethylene-(meth)acrylic acid ester (random, alternating) copolymer; polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBT); polyacrylate; polyvinyl chloride (PVC); polyurethane; polycarbonate; polyphenylene sulfide (PPS); polyamides such as aliphatic polyamides and fully aromatic polyamides (aramids); polyether ether ketone (PEEK); polyimide; polyetherimide; polyvinylidene chloride; ABS (acrylonitrile-butadiene-styrene copolymer); cellulose or cellulose derivatives; silicone-containing polymers; and fluorine-containing polymers. These can be used individually or in combination of two or more.

[0065] The base layer 21 is preferably composed of a polymer material such as a resin film. If the base layer 21 has a resin film, the resin film may be subjected to stretching or other treatments to control its deformability, such as its elongation rate. The surface of the base layer 21 may be surface-treated to improve adhesion with the adhesive layer 22. Possible surface treatments include chemical or physical oxidation treatments such as chromic acid treatment, ozone exposure, flame exposure, high-voltage electric shock exposure, and ionization radiation treatment. Alternatively, the base layer may be coated with an anchor coating agent, primer, adhesive, or other coating agent.

[0066] The base layer 21 may be a single layer or may consist 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.

[0067] The back side of the base material layer 21 (the side where the adhesive layer 22 does not overlap) may be treated with a release agent (release agent) such as a silicone resin or a fluororesin to provide release properties. The base layer 21 is preferably a light-transmitting (ultraviolet-transmitting) resin film or the like, as it allows active energy rays such as ultraviolet light to be supplied to the adhesive layer 22 from the back side.

[0068] The dicing tape 20 described above may include a release sheet that covers one side of the adhesive layer 22 (the side where the adhesive layer 22 does not overlap with 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.

[0069] As the release sheet, for example, a plastic film or paper that has been surface-treated with a release agent such as a silicone-based release agent, a long-chain alkyl-based release agent, a fluorine-based release agent, or a molybdenum sulfide release agent can be used. Furthermore, the release sheet can be used as a support material to support the adhesive layer 22. In particular, the release sheet is preferably used when layering the adhesive layer 22 on top of the base layer 21. Specifically, the adhesive layer 22 can be layered on top of the base layer 21 by layering the adhesive layer 22 on top of the base layer 21 with the release sheet and the adhesive layer 22 laminated together, and then peeling off (transferring) the release sheet.

[0070] The dicing die bond film 1 of this embodiment may include a release sheet that covers one side of the die bond sheet 10 (the side of the die bond sheet 10 that does not overlap with the adhesive layer 22) before use. The release sheet is used to protect the die bond sheet 10 and is peeled off immediately before the adherend (e.g., a semiconductor wafer) is attached 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 preferably used when the die bond sheet 10 is overlaid on the adhesive layer 22. Specifically, with the release sheet and the die bond sheet 10 laminated, the die bond sheet 10 is overlaid on the adhesive layer 22, and after overlaying, the release sheet is peeled off (transferred), whereby the die bond sheet 10 can be overlaid on the adhesive layer 22.

[0071] <Die bond sheet of dicing die bond film> As shown in FIG. 1, the die bond sheet 10 is overlaid on the adhesive layer 22 of the above-described dicing tape 20.

[0072] Regarding the peeling force between the adhesive layer 22 and the die bond sheet 10, it is preferable that the peeling force (A) before the adhesive layer 22 is cured by active energy rays and the peeling force (B) after curing satisfy the following formula (1). Note that the numerical value of (A) / (B) below may be 25.0 or less. (A) / (B)>7.0 Formula (1) By satisfying the above formula (1), chip floating can be more sufficiently suppressed while exhibiting better pick-up properties. In order to measure the peeling force (B) after curing, the above peeling force is measured after the adhesive layer 22 is sufficiently cured. For example, using a high-pressure mercury lamp (60 mW / cm 2 ), active energy rays with an intensity of at least 150 mJ / cm are irradiated from the substrate layer side to cure the adhesive layer. 2

[0073] [[ID='21]] The peeling force between the adhesive layer 22 and the die bond sheet 10 may be 0.30 [N / 20 mm] or more, or may be 0.50 [N / 20 mm] or more before the adhesive layer 22 is cured by active energy rays (that is, the value of (A) above). The value of (A) may be 2.50 [N / 20 mm] or less, or may be 1.90 [N / 20 mm] or less. Thereby, so-called chip floating can be more sufficiently suppressed.

[0074] The peeling force between the adhesive layer 22 and the die bond sheet 10 may be 0.03 [N / 20mm] or greater, 0.05 [N / 20mm] or greater, or greater than 0.06 [N / 20mm] after the adhesive layer 22 has been cured by the active energy rays (i.e., the value of (B) above). The value of (A) may be 0.10 [N / 20mm] or less, 0.09 [N / 20mm] or less, or less than 0.09 [N / 20mm]. This allows for better pickup performance.

[0075] The value of (A) above can be increased, for example, by increasing the content of radically polymerizable carbon-carbon double bonds in the acrylic copolymer in the adhesive layer 22. Alternatively, the value of (A) above can be increased, for example, by increasing the content of the hydroxyl group-containing (meth)acrylate units in the acrylic copolymer. The value of (B) above can be reduced, for example, by increasing the content of radically polymerizable carbon-carbon double bonds in the acrylic copolymer in the adhesive layer 22. Furthermore, the value of (B) above can be reduced by increasing the content of the aliphatic alkyl (meth)acrylate units in the acrylic copolymer. By changing (A) and (B) as described above, the value of (A) / (B) can be adjusted.

[0076] The Diebond sheet 10 contains a crosslinkable group-containing acrylic polymer having crosslinkable groups in its molecule that undergo 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.

[0077] The above-described acrylic polymer containing crosslinkable groups typically has the above-described crosslinkable groups in its side chains. The above-described acrylic polymer containing crosslinkable groups may also have the above-described crosslinkable groups at the ends of its side chains. Furthermore, the above-described acrylic polymer containing crosslinkable groups may have the above-described crosslinkable groups at at least one of the ends of its main chain.

[0078] The crosslinkable group contained in the above-mentioned acrylic polymer is not particularly limited as long as it is a functional group that undergoes a crosslinking reaction by thermal curing treatment.

[0079] Examples of crosslinkable groups include hydroxyl groups and carboxyl groups. These crosslinkable groups can undergo crosslinking reactions with epoxy groups or isocyanate groups. For example, the above-mentioned acrylic polymer containing crosslinkable groups, which has at least one of a hydroxyl group or a carboxyl group in its molecule, can undergo crosslinking reactions with compounds that have epoxy groups or isocyanate groups in their molecule (for example, epoxy resins described later).

[0080] Examples of crosslinkable groups include epoxy groups and isocyanate groups. These crosslinkable groups can undergo crosslinking reactions with hydroxyl groups and carboxyl groups. For example, the above-mentioned acrylic polymer containing crosslinkable groups, which has at least one of epoxy groups or isocyanate groups in its molecule, can undergo crosslinking reactions with compounds that have at least one of hydroxyl groups or carboxyl groups in their molecule (for example, phenol resins, which will be described later).

[0081] In this embodiment, it is preferable that the crosslinkable group-containing acrylic polymer contained in the die bond sheet 10 contains at least one of a carboxyl group or an epoxy group as a crosslinkable group. This allows the die bond sheet 10 to adhere to the substrate more effectively. Furthermore, in order to exhibit better adhesion to the substrate after curing (details to be described later), the die bond sheet 10 is required to have relatively high cohesive force after curing. To increase the cohesive force after curing, the organic components contained in the die bond sheet 10 must undergo sufficient crosslinking reactions and the die bond sheet 10 must be sufficiently cured. In order to ensure sufficient curing, it is preferable that the acrylic polymer containing the crosslinkable group has a relatively reactive functional group such as an epoxy group (glycidyl group) or a carboxyl group.

[0082] In the above-described acrylic polymer containing crosslinkable groups, the proportion of constituent units of the crosslinkable group-containing monomer may be 0.1% by mass or more and 60.0% by mass or less, 0.5% by mass or more and 40.0% by mass or less, 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, the curing of the die bond sheet 10 during the heat curing treatment can be carried out more sufficiently. On the other hand, when the above ratio is 60.0% by mass or less, the crosslinking reactivity of the crosslinkable group-containing acrylic polymer can be appropriately suppressed, thereby improving its stability over time. When the above-mentioned crosslinkable group-containing acrylic polymer has a hydroxyl group or a carboxyl group as a crosslinkable group in its molecule, the proportion of the constituent 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, 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 above-mentioned crosslinkable group-containing acrylic polymer has epoxy groups as crosslinkable groups in its molecule, the proportion of constituent units containing epoxy groups in the crosslinkable group-containing acrylic polymer may be 5% by mass or more and 60% by mass or less, 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 constituent units are the structures derived from each monomer (e.g., 2-ethylhexyl acrylate, hydroxyethyl acrylate, etc.) after polymerization when preparing a crosslinkable group-containing acrylic polymer. The same applies hereafter.

[0083] The die bond sheet 10 of this embodiment may contain one type of crosslinkable group-containing acrylic polymer, or it may contain multiple types (for example, two types) of crosslinkable group-containing acrylic polymers.

[0084] For example, if the Diebond sheet 10 contains two types of acrylic polymers containing crosslinkable groups, the crosslinkable groups of one of the two acrylic polymers will crosslink with the other. Specifically, an acrylic polymer containing crosslinkable groups having at least one of a hydroxyl group or a carboxyl group as a crosslinkable group in its molecule and an acrylic polymer containing crosslinkable groups having at least one of an epoxy group or an isocyanate group as a crosslinkable group in its molecule can crosslink with each other.

[0085] The above-mentioned acrylic polymers containing crosslinkable groups can be synthesized, for example, by a general polymerization method using a radical polymerization initiator.

[0086] The above-mentioned crosslinkable group-containing acrylic polymer preferably contains alkyl (meth)acrylate monomers in the largest mass proportion among the constituent units of the molecule. Examples of such alkyl (meth)acrylate monomers include C1 to C18 alkyl (meth)acrylate monomers having 1 to 18 carbon atoms in the alkyl group (hydrocarbon group).

[0087] Examples of alkyl (meth)acrylate monomers include saturated linear alkyl (meth)acrylate monomers and saturated branched alkyl (meth)acrylate monomers.

[0088] 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, and stearyl (meth)acrylate. Preferably, the number of carbon atoms in the linear alkyl group is between 2 and 8. Examples of saturated branched alkyl (meth)acrylate monomers include isoheptyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, isodecyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. The alkyl group portion may have an iso structure, sec structure, neo structure, or tert structure.

[0089] The above-mentioned crosslinkable group-containing acrylic polymer contains structural units derived from crosslinkable group-containing monomers that can copolymerize with alkyl (meth)acrylate monomers. In this embodiment, the above-mentioned crosslinkable group-containing acrylic polymer is an acrylic polymer copolymerized with at least an alkyl (meth)acrylate monomer and a crosslinkable group-containing monomer. In other words, the above-mentioned crosslinkable group-containing acrylic polymer has a structure in which the constituent units of the alkyl (meth)acrylate monomer and the constituent units of the crosslinkable group-containing monomer are linked together in a random order.

[0090] Examples of the above-mentioned crosslinkable group-containing monomers include carboxyl group-containing (meth)acrylic monomers, acid anhydride (meth)acrylic monomers, hydroxyl group-containing (meth)acrylic monomers, epoxy group-containing (glycidyl group)-containing (meth)acrylic monomers, isocyanate group-containing (meth)acrylic monomers, sulfonic acid group-containing (meth)acrylic monomers, phosphate group-containing (meth)acrylic monomers, acrylamide, and monomers containing functional groups such as acrylonitrile. The above-mentioned crosslinkable group-containing monomers may also contain ether groups or ester groups in their molecules.

[0091] The above crosslinkable group-containing acrylic polymer is preferably, A crosslinkable group-containing monomer selected from the group consisting of carboxyl group-containing (meth)acrylic monomers, hydroxyl group-containing (meth)acrylic monomers, epoxy group-containing (meth)acrylic monomers, and isocyanate group-containing (meth)acrylic monomers, It is a copolymer of alkyl (meth)acrylate (especially alkyl (meth)acrylate with 8 or fewer carbon atoms in the alkyl portion).

[0092] Examples of carboxyl group-containing (meth)acrylic monomers include (meth)acrylic acid and mono(2-(meth)acryloyloxyethyl) succinate monomers. The carboxyl group may be located at the terminal end of the monomer structure or bonded to hydrocarbons other than the terminal end. Examples of hydroxyl group-containing (meth)acrylic monomers include hydroxyethyl (meth)acrylate monomer, hydroxypropyl (meth)acrylate monomer, and hydroxybutyl (meth)acrylate monomer. The hydroxyl group may be located at the terminal end of the monomer structure, or it may be bonded to hydrocarbons other than the terminal end. Examples of epoxy group-containing (meth)acrylic monomers include glycidyl (meth)acrylate monomers and 4-hydroxybutyl (meth)acrylate glycidyl ether. The epoxy group may be located at the terminal end of the monomer structure or bonded to hydrocarbons other than the terminal end. Examples of isocyanate group-containing (meth)acrylic monomers include 2-methacryloyloxyethyl isocyanate, 1,1-(bisacryloyloxymethyl)ethyl isocyanate, 2-acryloyloxyethyl isocyanate, and 2-(2-methacryloyloxyethyloxy)ethyl isocyanate.

[0093] The diebond sheet 10 may contain components other than the crosslinkable group-containing acrylic polymer described above. For example, the diebond sheet 10 may further contain at least one of a thermosetting resin or a thermoplastic resin other than the crosslinkable group-containing acrylic polymer described above.

[0094] Examples of thermosetting resins include epoxy resins, phenolic resins, amino resins, unsaturated polyester resins, polyurethane resins, silicone resins, and thermosetting polyimide resins. One or more of these thermosetting resins may be used.

[0095] Examples of the epoxy resins mentioned above 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, tetraphenyloleethane type, hydantoin type, trisglycidyl isocyanurate type, or glycidylamine type epoxy resins.

[0096] Phenolic resins can act as curing agents for epoxy resins. Examples of phenolic resins include novolac-type phenolic resins, resol-type phenolic resins, and polyoxystyrenes such as polyparaoxystyrene. Examples of novolac-type phenolic resins include phenol novolac resin, phenol aralkyl resin, cresol novolac resin, tert-butylphenol novolac resin, and nonylphenol novolac resin. The hydroxyl group equivalent [g / eq] of the phenolic resin may be, for example, 90 to 220. The above-mentioned phenolic resin may be of one type or two or more types.

[0097] In this embodiment, the die bond sheet 10 may contain the above-mentioned crosslinkable group-containing acrylic polymer and thermosetting resin that crosslink with each other. Alternatively, the die bond sheet 10 may contain multiple types of crosslinkable group-containing acrylic polymers that crosslink with each other.

[0098] For example, the die bond sheet 10 may contain a carboxyl group-containing acrylic polymer or a hydroxyl group-containing acrylic polymer as a crosslinkable group-containing acrylic polymer, and may also contain an epoxy resin as a thermosetting resin. This allows the carboxyl group or hydroxyl group of the crosslinkable group-containing acrylic polymer to crosslink with the epoxy group of the epoxy resin, enabling the die bond sheet 10 to cure sufficiently.

[0099] Examples of thermoplastic resins other than the above-mentioned crosslinkable group-containing acrylic polymers that may be included in the Diebond 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 resins such as 6-polyamide resin and 6,6-polyamide resin, phenoxy resin, acrylic resins that do not contain crosslinkable functional groups in their molecules, saturated polyester resins such as PET and PBT, polyamide-imide resin, fluororesin, and the like. The above thermoplastic resin may be of one type or two or more types.

[0100] The content of the above-mentioned crosslinkable group-containing acrylic polymer in 100 parts by mass of 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.

[0101] In the die bond sheet 10, the content ratio of the above-mentioned crosslinkable group-containing acrylic polymer 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, relative to 100 parts by mass of organic components excluding fillers (for example, the above-mentioned crosslinkable group-containing acrylic polymer, thermosetting resin, curing catalyst, silane coupling agent, dye, etc.). The elasticity and viscosity of the die bond sheet 10 can be adjusted by changing the content ratio of the thermosetting resin in the die bond sheet 10. On the other hand, the content ratio of the thermosetting resin per 100 parts by mass of the above organic component may be 40 parts by mass or less, or 10 parts by mass or less.

[0102] The die bond sheet 10 may or may not contain a filler. By changing the amount of filler in the die bond sheet 10, the elasticity and viscosity of the die bond sheet 10 can be more easily adjusted. Furthermore, the physical properties of the die bond sheet 10, such as electrical conductivity, thermal conductivity, and elastic modulus, can be adjusted. Examples of fillers include inorganic fillers and organic fillers. Inorganic fillers are preferred as fillers. Examples of inorganic fillers include 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. The material of the inorganic filler may be a single metal such as aluminum, gold, silver, copper, or nickel, or an alloy. Fillers such as aluminum borate whiskers, amorphous carbon black, and graphite may also be used. The filler may take various shapes, such as spherical, needle-shaped, or flake-shaped. Only one type of filler, or two or more types, may be used.

[0103] If the die bond sheet 10 contains a filler, the filler content may be 50% by mass or less, 40% by mass or less, or 30% by mass or less of the total mass of the die bond sheet 10. The filler content may also be, for example, 5% by mass or more.

[0104] The Dyebond sheet 10 may contain other components as needed. Examples of these other components include curing catalysts, flame retardants, silane coupling agents, ion trapping agents, dyes, and the like. Examples of flame retardants include antimony trioxide, antimony pentoxide, and brominated epoxy resins. Examples of silane coupling agents include β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-glycidoxypropylmethyldiethoxysilane. Examples of ion trapping agents include hydrotalcites, bismuth hydroxide, and benzotriazole. In addition to the above-mentioned additives, one or more types may be used.

[0105] The die bond sheet 10 preferably contains the above-mentioned crosslinkable group-containing acrylic polymer, thermosetting resin, and filler, in that its elasticity and viscosity can be easily adjusted.

[0106] The thickness of the die bond sheet 10 is not particularly limited, but for example, it is between 1 μm and 200 μm. Such a thickness may also be between 3 μm and 150 μm, or between 5 μm and 100 μm. If the die bond sheet 10 is a laminate, the above thickness is the total thickness of the laminate.

[0107] The diebond sheet 10 may have a single-layer structure, for example, as shown in Figure 1. In this specification, a single layer means having only layers formed of the same composition. A configuration in which multiple layers formed of the same composition are laminated together is also considered a single layer. On the other hand, the diebond sheet 10 may have a multilayer structure in which layers formed from two or more different compositions are laminated. If the diebond sheet 10 has a multilayer structure, at least one layer constituting the diebond sheet 10 may contain the above-mentioned crosslinkable group-containing acrylic polymer and optionally further contain a thermosetting resin.

[0108] Next, the manufacturing methods for the die bond sheet 10 and the dicing die bond film 1 of this embodiment will be described.

[0109] <Method for manufacturing dicing die bond film> The method for manufacturing the dicing die bond film 1 of this embodiment is: The process of manufacturing the die bond sheet 10, The process of making dicing tape 20, The process includes a step of overlapping the manufactured die bond sheet 10 and the dicing tape 20.

[0110] <Process for manufacturing die-bonded sheets> The process for manufacturing the die bond sheet 10 is as follows: A resin composition preparation step for preparing a resin composition for forming a die bond sheet 10, The process includes a die bond sheet forming step of forming a die bond sheet 10 from a resin composition.

[0111] In the resin composition preparation step, for example, the above-mentioned crosslinkable group-containing acrylic polymer is mixed with an epoxy resin, an epoxy resin curing catalyst, a phenolic resin, or a solvent, and the resin is dissolved in the solvent to prepare the 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.

[0112] In the die bond sheet formation process, for example, the resin composition prepared as described above is applied to a release sheet. The application method is not particularly limited, and general application methods such as roll coating, screen coating, and gravure coating can be used. Next, if necessary, the applied composition is solidified by desolvation treatment or curing treatment to form the die bond sheet 10.

[0113] <Process for making dicing tape> The process for making dicing tape is: The synthesis process for synthesizing acrylic copolymers, A step to prepare an adhesive layer 22 by volatilizing the solvent from an adhesive composition containing the above-mentioned acrylic copolymer, an isocyanate compound, a polymerization initiator, a solvent, and other components added as appropriate depending on the purpose, A substrate layer fabrication process for creating the substrate layer 21, The method includes a lamination step of bonding the adhesive layer 22 and the base material layer 21 together to laminate the base material layer 21 and the adhesive layer 22.

[0114] In the synthesis process, for example, an acrylic copolymer intermediate is synthesized by radical polymerization of the above-mentioned long-chain alkyl (meth)acrylate monomer and a hydroxyl group-containing (meth)acrylic monomer. Radical polymerization can be carried out by general methods. For example, an acrylic copolymer intermediate can be synthesized by dissolving each of the above monomers in a solvent, stirring while heating, and adding a polymerization initiator. Polymerization may be carried out in the presence of a chain transfer agent to adjust the molecular weight of the acrylic copolymer. 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 through a urethane reaction. As a result, some of the hydroxyl group-containing (meth)acrylate units become polymerizable (meth)acrylate units containing radical polymerizable carbon-carbon double bonds. The urethane reaction can be carried out by a general method. For example, an acrylic copolymer intermediate and an isocyanate-containing polymerizable monomer are stirred while heating in the presence of a solvent and a urethane catalyst. This allows for the urethane bonding of some of the hydroxyl groups of the acrylic copolymer intermediate to the isocyanate groups of the isocyanate-containing polymerizable monomer.

[0115] In the adhesive layer preparation process, for example, an acrylic copolymer, an isocyanate compound, and a polymerization initiator are dissolved in a solvent to prepare an adhesive composition. The viscosity of the composition can be adjusted by changing the amount of solvent. Next, the adhesive composition is applied to a release sheet. Common application methods such as roll coating, screen coating, and gravure coating are used. The applied adhesive composition is solidified by desolvation treatment, solidification treatment, etc., to produce an adhesive layer 22.

[0116] In the substrate layer preparation process, the substrate layer can be prepared by forming a film using a general method. Examples of film formation methods include calendering, casting in organic solvents, inflation extrusion in a closed system, T-die extrusion, and dry lamination. Co-extrusion molding may also be used. In addition, commercially available films or the like may be used as the substrate layer 21.

[0117] In the lamination process, the adhesive layer 22 and the base material layer 21 are laminated together while the release sheet is overlapping it. The release sheet may remain overlapping the adhesive layer 22 until just before use. Furthermore, in order to promote the reaction between the crosslinking agent and the acrylic copolymer, and to promote the reaction between the crosslinking agent and the surface portion of the substrate layer 21, an aging process may be carried out after the lamination process at a temperature of 50°C for 48 hours.

[0118] These processes enable the manufacture of the dicing tape 20.

[0119] <Step of overlapping the die bond sheet 10 and the dicing tape 20> In the process of overlapping the diebond sheet 10 and the dicing tape 20, the diebond sheet 10 is attached to the adhesive layer 22 of the dicing tape 20 manufactured as described above.

[0120] In this bonding process, the release sheets are peeled off from the adhesive layer 22 of the dicing tape 20 and from the die bond sheet 10, respectively, and the two are bonded together so that the die bond sheet 10 and the adhesive layer 22 are in direct contact. For example, they can be bonded by pressing. The bonding temperature is not particularly limited, but is, for example, 30°C to 50°C, preferably 35°C to 45°C. The bonding pressure is not particularly limited, but is preferably 0.1 kgf / cm to 20 kgf / cm, more preferably 1 kgf / cm to 10 kgf / cm.

[0121] The dicing die bond film 1 manufactured through the process described above is used, for example, as an auxiliary tool for manufacturing semiconductor devices (semiconductor integrated circuits). The manufacturing method of semiconductor devices (method of using the dicing die bond film) will be described below.

[0122] <Method of manufacturing semiconductor devices (Method of using dicing die bond film when manufacturing semiconductor devices)> In semiconductor device manufacturing methods, chips are generally cut from a semiconductor wafer on which a circuit surface has been formed and then assembled. In this process, the dicing die bond film of this embodiment is used as a manufacturing aid.

[0123] The method for manufacturing a semiconductor device according to this embodiment is: A cutting process in which a wafer (semiconductor wafer) with a circuit surface formed on it is cut into chips, The process includes a pickup step of peeling off the die bond sheet, which is attached to the adhesive layer of the dicing die bond film described above, from the adhesive layer together with the chip.

[0124] In the semiconductor device manufacturing method of this embodiment, the dicing step includes, for example, a stealth dicing step in which a weak portion is formed inside a semiconductor wafer to which a backgrind tape is attached using laser light, and the semiconductor wafer is prepared to be processed into a chip (die) by a dicing process; a backgrinding step in which the semiconductor wafer to which the backgrind tape is attached is ground to reduce its thickness; a mounting step in which one side of the semiconductor wafer whose thickness has been reduced (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 step in which the semiconductor wafer is diced by stretching the dicing tape 20 to produce chips (dies) and to widen the spacing between the chips. In the pickup process, the die bond sheet 10 and the adhesive layer 22 are separated, and the semiconductor chip (die) is removed with the die bond sheet 10 still attached. The semiconductor device manufacturing method of this embodiment further includes a die bonding step of adhering a die bond sheet 10 attached to a semiconductor chip (die) to a substrate, a curing step of hardening the die bond sheet 10 adhering to the substrate, a wire bonding step of electrically connecting the electrodes of the electronic circuit on the semiconductor chip (die) to the substrate with wires, and a sealing step of sealing the semiconductor chip (die) and wires on the substrate with a thermosetting resin.

[0125] 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 Figures 2A to 2C, a weak portion is formed inside the semiconductor wafer W for cleaving the wafer with the circuit surface into chips (dies). Specifically, a backgrind tape G is attached to the circuit surface of the semiconductor wafer W (see Figure 2A). With the backgrind tape G attached, the semiconductor wafer W is ground with a grinding pad K (pre-backgrinding) until it reaches a predetermined thickness (see Figure 2B). By irradiating the thinned semiconductor wafer W with laser light, a weak portion is formed inside the semiconductor wafer W (see Figure 2C).

[0126] Instead of the stealth dicing process, a half-cutting process may be performed. The half-cutting process is a step in the so-called DBG (Dicing Before Grinding) process. In the half-cutting process, grooves are formed in the semiconductor wafer to process it into chips (dies) through a cleavage process, and then the semiconductor wafer is ground down to reduce its thickness. Specifically, in the half-cut process, a wafer with a circuit surface (pattern wafer) is subjected to a half-cut process to divide it into chips (dies). More specifically, wafer processing tape is attached to the side of the semiconductor wafer opposite to the circuit surface. A dicing ring is also attached to the wafer processing tape. With the wafer processing tape attached, grooves for division are formed. Backgrind tape is attached to the grooved surface while the initially attached wafer processing tape is peeled off.

[0127] 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 dicing a semiconductor wafer, as described above.

[0128] In the backgrinding process, as shown in Figure 2D, the semiconductor wafer W to which the backgrinding tape G is attached is further ground to reduce the thickness of the semiconductor wafer W until it reaches the thickness of the chips (dies) that will be produced by the subsequent cutting process. For example, grinding may be performed until a predetermined thickness is reached so that the half-cut semiconductor wafer W does not become individualized. When grinding is performed in this manner, the subsequent expansion process (especially the low-temperature expansion process) will cut the semiconductor wafer W into chips and simultaneously cut the die bond sheet 10. Alternatively, grinding may be performed until the half-cut semiconductor wafer W becomes individualized. When grinding is performed in this manner, the subsequent expansion process (especially the low-temperature expansion process) will, for example, widen the spacing between adjacent chips and simultaneously cut the die bond sheet 10.

[0129] In the mounting process, the semiconductor wafer W is fixed to the dicing tape 20 as shown in Figures 3A and 3B. Specifically, the 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 as described above, is attached to the exposed surface of the die bond sheet 10 (see Figure 3A). Subsequently, the backgrind tape G is peeled off from the semiconductor wafer W (see Figure 3B).

[0130] Before the expansion process, the die bond sheet 10 may be cut by, for example, laser irradiation. Specifically, when the semiconductor wafer W is individualized by the above cutting process, the die bond sheet 10 that overlaps the individualized chips of the semiconductor wafer and has not yet been cut may be cut by laser irradiation. After that, the spacing between adjacent chips may be widened by the expansion process.

[0131] In the expanding process, as shown in Figures 4A to 4C, the spacing between semiconductor chips (dies) X created by cleavage is increased. Specifically, after attaching the dicing ring R to the adhesive layer 22 of the dicing tape 20, it is fixed to the holder H of the expanding device (see Figure 4A). The push-up member U of the expanding device is pushed up from below the dicing die bond film 1, stretching the dicing die bond film 1 in the planar direction (see Figure 4B). This causes the semiconductor wafer W to cleave under specific temperature conditions. The above 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 Figure 4C; this concludes the low-temperature expanding process). Furthermore, in the expanding process, as shown in Figures 5A to 5B, the dicing tape 20 is stretched to increase its surface area under higher temperature conditions (e.g., 10°C to 25°C). This pulls adjacent semiconductor chips X apart in the planar direction of the film surface after cleavage, further widening the kerf (spacing) (room temperature expanding process). Furthermore, when implementing the DBG process described above, the expansion process may involve either cutting the die bond sheet at a low temperature or cutting the die bond sheet with a laser. If the die bond sheet is cut with a laser, the expansion process may be performed again at a low temperature after cutting the die bond sheet.

[0132] Before the pick-up process, for example, the adhesive layer 22 superimposed on the base layer 21 is cured by irradiating it with ultraviolet light from the base layer 21 side (curing process).

[0133] In the pickup process, as shown in Figure 6, the semiconductor chip X to which the die bond sheet 10 is attached is peeled off from the adhesive layer 22 of the dicing tape 20. Specifically, the pin member P is raised to push up the semiconductor chip X to be picked up via the dicing tape 20. The pushed-up semiconductor chip X is held by the suction jig J. By using the dicing die bond film of this embodiment described above, good pick-up performance can be achieved in the pick-up process.

[0134] In the die bonding process, the semiconductor chip X with the die bonding sheet 10 attached is bonded to the substrate Z. In the die bonding process, multiple stacks of semiconductor chips X with the die bonding sheet 10 attached may be made, for example, as shown in Figure 7. Thus, when manufacturing chip-embedded semiconductor devices (FOD [Film on Die] type semiconductor devices), the die bonding sheet 10 may be used to embed the semiconductor chip.

[0135] In the curing process, a heat treatment is performed at a temperature of, for example, 100°C to 180°C to enhance the reaction activity of the crosslinking groups (e.g., epoxy groups) in the crosslinking group-containing acrylic polymer contained in the die bond sheet 10 and to promote the curing of the die bond sheet 10.

[0136] In the wire bonding process, as shown in Figure 8, the semiconductor chip X (die) and the adherend Z are heated while being connected with a wire L. As a result, the crosslinkable groups in the aforementioned crosslinkable group-containing acrylic polymer contained in the die bond sheet 10 become reactive again upon heating, and the curing reaction of the die bond sheet 10 can proceed. In addition, during the wire bonding process, compressive force may be applied to the die bond sheet 10 in the thickness direction.

[0137] In the sealing process, as shown in Figure 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, for example, 100°C to 180°C to allow the curing reaction of the thermosetting resin M to proceed.

[0138] Furthermore, in the semiconductor industry in recent years, with the further advancement of integration technology, there is a demand for thinner semiconductor chips (for example, thicknesses of 20 μm to 50 μm) and thinner die bond sheets (for example, thicknesses of 1 μm to 40 μm, 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. When an electronic circuit is formed on one surface of a thin semiconductor chip, the semiconductor chip may not be able to withstand the internal stress and may deform slightly (such as warping), and this deformation may cause warping in the die bond sheet as well (see Figure 10). In the expansion process described above, particularly in the room-temperature expansion process, the dicing tape 20 is stretched with strong force in the planar direction. If the chip is warped, the dicing tape 20 and the die bond sheet 10 will separate, resulting in a phenomenon known as chip lifting. To suppress this chip lifting, a relatively high adhesive force is required between the dicing tape 20 and the die bond sheet 10 in the expansion process. On the other hand, in the pickup process, it is required that the die bond sheet 10 can be easily peeled off the dicing tape 20 (good pickup properties). To achieve these conflicting 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 expansion process for cleavage in the expansion process and the room-temperature expansion process for securing the chip-to-chip distance are performed when the adhesive layer 22 has relatively high adhesive strength before irradiation with active energy rays. On the other hand, the adhesive layer 22 is irradiated with active energy rays before the pickup process to reduce the adhesive strength of the adhesive layer 22. In this embodiment, when the cross-section of the adhesive layer 22 is observed with an electron microscope, a phase separation structure is observed. The phase separation structure includes a first phase containing radically polymerizable carbon-carbon double bonds and a second phase that separates from the first phase and has a lower content of radically polymerizable carbon-carbon double bonds than the first phase, with the area ratio of the first phase in the cross-section being higher than 50%. Thus, the adhesive layer 22 is designed so that the polarity of the adhesive layer 22 before curing is moderately high. This allows for a moderate increase in adhesion between the adhesive layer 22 before curing and the die bond sheet 10, enabling relatively strong adhesion between the adhesive layer 22 before curing and the die bond sheet 10. Therefore, the chip lifting phenomenon in the expansion process can be suppressed. Because there is a relatively large amount of the first phase with a higher content of radically polymerizable carbon-carbon double bonds, the adhesive layer 22 is designed so that the polarity of the adhesive layer 22 after curing by active energy rays is low. As a result, the adhesive layer 22 after curing by active energy ray irradiation has relatively low polarity. Therefore, the adhesion between the adhesive layer 22 and the die bond sheet 10 after irradiation with active energy rays can be weakened. In other words, after curing, the interfacial interaction between the adhesive layer 22 and the relatively polar die bond sheet 10 becomes smaller. Consequently, the peelability of the cured adhesive layer 22 from the die bond sheet 10 is improved. Therefore, good pick-up properties are achieved.

[0139] The dicing die bond film of this embodiment is as illustrated above, but the present invention is not limited to the dicing die bond film illustrated above. In other words, various forms used in general dicing die bond films can be adopted as long as they do not impair the effects of the present invention.

[0140] The matters disclosed herein include the following: (1) The dicing tape comprises a base layer and an adhesive layer superimposed on the base layer, and a die bond sheet superimposed on the dicing tape. The adhesive layer, when observed in cross-section with an electron microscope, has a phase-separated structure. The phase separation structure comprises a first phase containing radically polymerizable carbon-carbon double bonds and a second phase having a lower content of radically polymerizable carbon-carbon double bonds than the first phase and separated from the first phase. A dicing die bond film in which the area ratio of the first phase in the cross-section is higher than 50%. (2) The dicing die bond film according to (1) above, wherein the adhesive layer comprises an acrylic copolymer having polymerizable (meth)acrylate units containing radical polymerizable carbon-carbon double bonds as monomer units in its molecule. (3) The acrylic copolymer has at least one crosslinkable group-containing (meth)acrylate unit in its molecule, which has a crosslinkable group that undergoes a crosslinking reaction by curing treatment, as a monomer unit. In the aforementioned acrylic copolymer, the proportion of the crosslinkable group-containing (meth)acrylate units among the total monomer units is 18 mol% or more and 50 mol% or less. The dicing die bond film according to (2) above, wherein a portion of the crosslinkable group-containing (meth)acrylate units is the polymerizable (meth)acrylate unit. (4) The acrylic copolymer is a dicing die bond film according to (2) or (3) above, wherein the polymerizable (meth)acrylate units are present in an amount of 8 mol% to 35 mol% of the total monomer units. (5) The acrylic copolymer includes, as the monomer unit, a long-chain alkyl (meth)acrylate unit with 8 or more carbon atoms in the alkyl portion. The dicing die bond film according to any one of (2) to (4) above, wherein the proportion of the long-chain alkyl (meth)acrylate units among the total monomer units in the acrylic copolymer is 60 mol% or more and 82 mol% or less. (6) The acrylic copolymer contains aliphatic alkyl (meth)acrylate units with 12 or more carbon atoms in the alkyl portion as the long-chain alkyl (meth)acrylate units, The dicing die bond film according to (5) above, wherein the proportion of the aliphatic alkyl (meth)acrylate units to the total monomer units in the acrylic copolymer is 15 mol% or more and 40 mol% or less. (7) A dicing die bond film according to any one of (1) to (6) above, wherein the peeling force between the adhesive layer and the die bond sheet satisfies the following formula (1): peeling force (A) before the dicing tape is cured by active energy rays and peeling force (B) after curing. (A) / (B)>7.0 Equation (1) (8) The dicing die bond film according to any one of (1) to (7) above, wherein the surface modulus of the adhesive layer after curing by active energy rays is greater than 30 MPa and less than 400 MPa. (9) The acrylic copolymer contains the crosslinkable group-containing (meth)acrylate unit and the alkyl (meth)acrylate unit, The aforementioned crosslinkable group-containing (meth)acrylate unit comprises a hydroxyl group-containing (meth)acrylate unit and a polymerizable (meth)acrylate unit containing a radically polymerizable carbon-carbon double bond in the molecule. The dicing die bond film according to any one of (3) to (8) above, wherein the alkyl (meth)acrylate unit contains saturated branched alkyl (meth)acrylate units with 8 to 11 carbon atoms in the alkyl portion and saturated linear aliphatic alkyl (meth)acrylate units with 12 to 14 carbon atoms in the alkyl portion. (10) The dicing die bond film according to (9) above, wherein the molar ratio of the saturated branched alkyl (meth)acrylate units to the saturated linear aliphatic alkyl (meth)acrylate units in the acrylic copolymer is 1.0 or more and 5.0 or less. [Examples]

[0141] The present invention will be further explained with experimental examples, but the present invention is not limited to these.

[0142] Dicing tape was manufactured as follows. Furthermore, this dicing tape was laminated with a die bond sheet to produce a dicing die bond film.

[0143] <Making dicing tape> (Raw material monomers for acrylic copolymers) • 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) (Examples 1-4) / (Comparative Examples 1-5) The raw materials were placed in a reaction vessel equipped with a condenser, a nitrogen inlet, a thermometer, and a stirrer, according to the formulation shown in Table 1. 0.2 parts by weight of azobisisobutyronitrile (AIBN) was used as a thermal polymerization initiator for every 100 parts by weight of the total monomers. Ethyl acetate was added as the reaction solvent to achieve a predetermined concentration of total monomers (e.g., 35% by weight). The polymerization reaction was carried out at 62°C for a predetermined time (e.g., 3 hours) under a nitrogen atmosphere, and then at 75°C for a predetermined time (e.g., 4 hours) to obtain an acrylic copolymer intermediate. In each example and comparative example, the monomer concentration and polymerization time during polymerization are as shown in Table 2.

[0144] To the liquid containing the acrylic copolymer intermediate prepared as described above, 2-methacryloyloxyethyl isocyanate (hereinafter also referred to as MOI) was added in a molar ratio (indicated as polymerizable group-containing monomer units in Table 1) relative to the total amount of monomers blended during polymerization, as shown in Table 1. For example, in Example 1, MOI was added so that the MOI was 32 moles for a total of 100 moles of monomers blended during polymerization. In addition, 0.5% by mass of dibutyltin dilaurate was added as a reaction catalyst relative to the amount of MOI added. Subsequently, an addition reaction treatment (urethane reaction treatment) was carried out in an air stream at 50°C for 12 hours to obtain an acrylic copolymer. Next, the following components were added to 100 parts by mass of the acrylic copolymer to prepare an adhesive solution. • Photopolymerization initiator: 3 parts by mass per 100 parts by mass of the acrylic copolymer intermediate (Product name: Omnirad127D, manufactured by IGM) • Polyisocyanate compound: 0.8 parts by mass per 100 parts by mass of the acrylic copolymer intermediate. (Product name: "Coronate L", manufactured by Tosoh Corporation) • Antioxidant: 0.01 parts by mass per 100 parts by mass of acrylic copolymer intermediate (Product name "Irganox 1010", 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 heated and dried at 120°C for 2 minutes to form an adhesive layer with a thickness of 10 μm. Next, the adhesive layer and the base layer (polyolefin film (125 μm thick), manufactured by Gunze Corporation, product name "Funcrea NED#125") were laminated together, and the mixture was stored at 50°C for 24 hours to produce dicing tape.

[0145] <Preparation of Diebond Sheet> • Acrylic polymer: 100 parts by mass (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 mass (Product name "MEHC-7851SS", solid at 23°C, manufactured by Meiwa Kasei Co., Ltd.) • Silica filler: 10 parts by mass (Product name "SE2050-MCV", average particle size 500nm, manufactured by Admatex Corporation) Each of the above raw materials was added to a predetermined amount of methyl ethyl ketone and mixed to prepare an adhesive composition solution with a total solids content of 12% by mass. Next, the adhesive composition was applied to the silicone-release surface of a PET release liner (separator) having a silicone-release surface using an applicator to form a coating film. This coating film was heat-dried at 130°C for 2 minutes to produce a die bond sheet with a thickness of 10 μm on the PET release liner (separator).

[0146] <Manufacturing of dicing die bond film> A circular die-bond sheet was created by punching out a die-bond sheet in a 330mm diameter circle. At room temperature, a dicing die-bond film was manufactured by laminating the circular die-bond sheet with dicing tape using a laminator.

[0147] <Observation of phase separation structure within the adhesive layer> Two adhesive layers were prepared and bonded together. Then, using an ultramicrotome, the layers were thinned to a thickness of approximately 100 nm under a freezing atmosphere (-100°C). The ultrathin sectioning method described above was performed on the cross-section obtained by cutting the adhesive layer 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 and photographed using TEM. Furthermore, the observed photographs were analyzed to calculate the area percentage of the first phase (the phase with a higher polymerizable double bond content that appears darker due to staining). In cases where gray areas were present, the total area of ​​both the black and gray areas was considered the area of ​​the first phase. [Transmission Electron Microscope (TEM) Observation Conditions] Equipment: Hitachi,HT7820 Acceleration voltage: 100kV [Method for calculating area ratio] Image analysis software: Product name "ImageJ" Photo magnification: Observation magnification 12,000x Area analyzed in the observed image: 13 μm 2

[0148] <Measurement of physical properties of dicing die bond film> The physical properties of the dicing die bond films for each example and comparative example were measured as follows.

[0149] [Peel strength (adhesion) between the adhesive layer and the Dybond sheet] The details of the measurement method for the peeling force (adhesion force) before UV irradiation (before curing) and after UV irradiation (after curing) are as follows. The measurement results are shown in Table 1. The ratio of the peeling force (adhesion force) before curing to the peeling force (adhesion force) after curing is also shown in Table 1.

[0150] [Peel strength between the adhesive layer and the Dybond sheet (after UV irradiation)] The peeling force was measured using a T-type peel test. The sample for measurement was prepared as follows. The PET release liner (separator) was peeled off the die bond sheet, exposing one side of the die bond sheet. Backing tape (product name "ELP BT315", manufactured by Nitto Denko Corporation) was applied to the exposed side. A high-pressure mercury lamp (product name "UM-810", 60mW / cm²) manufactured by Nitto Seiki Co., Ltd. was used. 2 Using ), a strength of 150 mJ / cm² was measured from the substrate layer side. 2 The adhesive layer was cured by irradiation with ultraviolet light. Then, the adhesive layer was cut to dimensions of 50 mm in width and 120 mm in length to be used as a measurement sample. A T-type peel test was performed on the prepared measurement sample using a tensile testing machine (for example, 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.

[0151] [Peel strength between the adhesive layer and the Dybond sheet (before UV irradiation)] The peeling force was measured in the same manner as described above, except that the measurement was taken on the uncured adhesive layer that had not been irradiated with ultraviolet light, and the adhesive layer was cut to dimensions of 20 mm in width and 120 mm in length.

[0152] [Surface modulus of the adhesive layer after UV irradiation] The details of the method for measuring the surface modulus of the adhesive layer described above are as stated above. The measurement results for the surface modulus are shown in Table 1.

[0153] Table 1 shows the composition and physical properties of the die bond sheets in each example and comparative example. In Table 1, the mol% of “OH group-containing monomer units” and the mol% of “polymerizable group-containing monomer units” represent the mol% of hydroxyl group-containing (meth)acrylate units and the mol% of polymerizable (meth)acrylate units in the acrylic copolymer, respectively. Since the isocyanate groups of the above MOI and the hydroxyl groups of the hydroxyl group-containing (meth)acrylate units react to form urethane with almost 100% efficiency, the above mol% can be calculated based on the blending amounts when the acrylic copolymer was synthesized.

[0154] [Table 1]

[0155] [Table 2]

[0156] The performance of the dicing die bond film manufactured as described above was evaluated as follows.

[0157] <Performance evaluation (pickup capability based on pickup test)> The pickability of a semiconductor chip with a die bond sheet in a fractured state was evaluated. A semiconductor chip with a die bond sheet in a fractured state was obtained as follows. Specifically, a 12-inch bare wafer (300 mm in diameter, 55 μm thick) had a groove (10 mm x 10 mm) formed for division by a half-cut process. A back-grind tape was then applied to the side of the wafer with the division groove. Subsequently, a back grinder (DISCO, model DGP8760) was used to grind the surface of the 12-inch bare wafer (the side opposite to the side where the back-grind tape was applied) to a depth of 25 μm. This resulted in a backgrounded bare wafer. A die-bond sheet of the dicing die-bond film for each example was applied to the side of the back-grinded bare wafer opposite to the side where the back-grind tape was applied. In this way, a bare wafer with a dicing die-bond film was obtained. This bare wafer with a dicing die-bond film was then cut using an expansion process. The expansion process was carried out using a die separator (product name "Die Separator DDS2300, manufactured by Disco Corporation") with the backgrind tape peeled off from the bare wafer. In addition, the expansion process consisted of cool expansion followed by room temperature expansion. Cool expansion was performed as follows. Specifically, a 12-inch diameter stainless steel 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. Then, the bare wafer with the attached stainless steel ring frame was mounted in a die separator. Cool expansion was performed 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 / second, and an expansion amount of 7 mm. After cool expansion, the semiconductor wafer was fragmented (individually separated) into multiple semiconductor chips. The die bond sheet was also fragmented to a size equivalent to that of a semiconductor chip. Thus, multiple semiconductor chips with die bond sheets were obtained. Room temperature expansion was performed after cool expansion as follows: Room temperature expansion was carried out by expanding the dicing tape of the dicing die bond film using the room temperature expansion unit of the die separator apparatus described above. The conditions at this time were an expansion temperature of 23±2℃, an expansion speed of 1 mm / second, and an expansion amount of 10 mm. After room temperature expansion, the dicing tape was subjected to a heat shrinkage treatment at a temperature of 200℃ for 20 seconds. After heating and shrinking the dicing tape, a pickup test was performed on the individual semiconductor chips with die-bonded sheets using a device with a pickup mechanism (product name "Die Bonder SPA-300", manufactured by Shinkawa Co., Ltd.). In this pickup test, the pushing speed by the pin member was set to 1 mm / second, and the pushing amount was set to 2000 μm. The pickup test was performed after the adhesive layer had hardened. The hardening treatment was performed using an ultraviolet irradiation unit (high-pressure mercury lamp, 70 mW / cm²) incorporated into the die-separating device. 2 Using ), 1000 mJ / cm³ is applied from the substrate layer side. 2 This was done by irradiating with ultraviolet light. The pickup test was performed on five semiconductor chips with die bond sheets. The evaluation criteria for pickup performance are as follows: ◎ (Good): All five semiconductor chips with die-bonded sheets can be picked up. ○: (Slightly good) Three or four out of five semiconductor chips with die-bonded sheets can be picked up. × (bad): Three or more of the five semiconductor chips with die-bonded sheets could not be picked up.

[0158] <Chip retention performance evaluation (evaluation of performance in suppressing chip lifting phenomenon)> A 300 mm diameter bare wafer (detailed below as "warped wafer") and a dicing ring were attached to the dicing die bond film of each example and comparative example manufactured as described above, while heating at a temperature of 50-80°C. Next, semiconductor wafers and die bond sheets were cleaved using a die separator DDS230 (manufactured by Disco), and the chip lift after cleavage 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 down to a thickness of 0.030 mm. Furthermore, to make the chip lifting phenomenon more likely to occur, a "warped wafer" prepared as described below was used as the bare wafer. [Fabrication of warped wafers] In the preparation of warped wafers, first, (a) to (f) below were dissolved in methyl ethyl ketone to obtain a warp-adjusting composition with a solid content concentration of 20% by mass. (a) Acrylic resin (manufactured by Nagase ChemteX, 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 Chemicals, 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 Admatex, product name "SO-25R"): 53 parts by mass (f) Phosphorus-based catalyst (TPP-K): 1 part by mass Next, using an applicator, the warpage adjustment composition was applied to a silicone-treated surface of a PET separator (50 μm thick), which served as a release liner, to a thickness of 25 μm. The solvent was removed from the warpage adjustment composition by drying at 130°C for 2 minutes. In this way, a warpage adjustment sheet was obtained in which a warpage adjustment layer was laminated on the release liner. Next, a bare wafer was attached to the side of the warp adjustment sheet where the release liner was not laminated, using a laminator (MCK, model MRK-600), under the conditions of 60°C, 0.1 MPa, and 10 mm / s. After that, it was placed in an oven and heated at 175°C for 1 hour to heat-cur the resin in the warp adjustment layer. As a result, a warped bare wafer was obtained due to the shrinkage of the warp adjustment layer. After shrinking the warp adjustment layer, wafer processing tape (manufactured by Nitto Denko Corporation, product name "V-12SR2") was applied to the side of the warped bare wafer where the warp adjustment layer was not laminated. Then, a dicing ring was fixed to the warped bare wafer via the wafer processing tape. Furthermore, the warp adjustment layer was removed from the warped bare wafer. Using a dicing apparatus (DISCO, model 6361), grooves with a depth of 100 μm from the surface were formed in a grid pattern (groove width 20 μm) on the entire surface of the warped bare wafer from which the warping adjustment layer had been removed (hereinafter referred to as "one side"). Next, a backgrind tape was attached to one side of the warped bare wafer, and the wafer processing tape was removed from the other side of the warped bare wafer (the side opposite to the aforementioned side). Next, using a back grinder (DISCO, model DGP8760), the warped bare wafer was ground from the other side until its thickness was 30 μm (0.030 mm). The wafer obtained in this way was designated as a warped wafer.

[0159] [Method for evaluating retention (suppression of tip lifting)] First, using a cool expander unit, the bare wafer and die bond sheet were cleaved under the conditions of an expansion temperature of -15°C, an expansion speed of 200 mm / second, and an expansion amount of 11 mm to obtain a semiconductor chip with a die bond sheet. Next, the expansion process was performed 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 heat-shrinked under the conditions of a heat temperature of 200°C, airflow of 40 L / min, heat distance of 20 mm, and rotation speed of 3° / sec. Next, with the dicing ring held in place by the dicing die bond film, the semiconductor chip with the die bond sheet attached was observed from the dicing tape side (the polyolefin film side, which is the base layer). The retention performance was then evaluated by calculating the contact rate of the semiconductor chip with the die bond sheet. Specifically, a microscope called "VHX-6000" (manufactured by Keyence Corporation) was used to take microscopic images from the dicing tape side. The resulting images were then analyzed using image analysis software (product name "ImageJ"). Furthermore, the area of ​​the portion where the semiconductor chip was not lifted from the die bond sheet was measured. The area of ​​the semiconductor chip was also calculated based on its size. 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 this contact rate value, the retention performance was evaluated according to the following evaluation criteria. ○: Contact rate is 60% or higher ×: Contact rate is less than 60%

[0160] As can be seen from the evaluation results above, the dicing die bond film of the example was better than the dicing die bond film of the comparative example in terms of chip lifting suppression performance and also in terms of pick-up performance.

[0161] The adhesive layer of the dicing die bond film in the example has a phase separation structure when observed in cross-section with an electron microscope. The phase separation structure comprises a first phase containing radically polymerizable carbon-carbon double bonds and a second phase that is separated from the first phase and has a lower content of radically polymerizable carbon-carbon double bonds than the first phase, with the area ratio of the first phase in the cross-section being higher than 50%. By using a dicing die bond film having such a configuration in the manufacture of a semiconductor device, semiconductor devices can be manufactured efficiently. In the manufacture of a semiconductor device, in the expansion process, a relatively large adhesive force is required between the adhesive layer and the die bond sheet in order to suppress the chip lifting phenomenon described above. On the other hand, after curing the adhesive layer by irradiating it with active energy rays such as ultraviolet light before the pickup process, it is necessary that the die bond sheet be easily peeled off from the cured adhesive layer (exhibition of good pickup properties). In order to exhibit these conflicting properties, the adhesive layer in the example has a microscopic phase separation structure, and in the cross-section, the area ratio of the first phase, which has a higher content of radically polymerizable carbon-carbon double bonds, is higher than 50%. By including a relatively large amount of the more polar first phase, the adhesion between the die bond sheet and the adhesive layer before curing is not excessively reduced, resulting in good adhesion. On the other hand, the adhesion between the die bond sheet and the adhesive layer after curing is reduced due to the disappearance of double bonds. Therefore, the chip lifting phenomenon can be suppressed before the adhesive layer cures, and good pick-up properties can be achieved after the adhesive layer cures. [Industrial applicability]

[0162] The dicing die bond film of the present invention is suitably used, for example, as an auxiliary tool when manufacturing semiconductor devices (semiconductor integrated circuits). [Explanation of Symbols]

[0163] 1: Dicing die bond film, 10: Diebond sheet, 20: Dicing tape, 21: Base material layer, 22: Adhesive layer.

Claims

1. The invention comprises a dicing tape having a base layer and an adhesive layer superimposed on the base layer, and a die bond sheet superimposed on the dicing tape, The adhesive layer contains an acrylic polymer having polymerizable (meth)acrylate units containing radical polymerizable carbon-carbon double bonds as monomer units in its molecule. The acrylic polymer has at least one crosslinkable group-containing (meth)acrylate unit in its molecule, which has a crosslinkable group that undergoes a crosslinking reaction by curing treatment, as the monomer unit. A portion of the crosslinkable group-containing (meth)acrylate units is the polymerizable (meth)acrylate unit, In the acrylic polymer, the proportion of the monomer units that are crosslinkable group-containing (meth)acrylate units is 18 mol% or more and 50 mol% or less. The adhesive layer, when observed in cross-section with an electron microscope, has a phase-separated structure. The phase separation structure comprises a first phase containing radically polymerizable carbon-carbon double bonds and a second phase having a lower content of radically polymerizable carbon-carbon double bonds than the first phase and being separated from the first phase. A dicing die bond film in which the area ratio of the first phase in the cross-section is higher than 50%.

2. The invention comprises a dicing tape having a base layer and an adhesive layer superimposed on the base layer, and a die bond sheet superimposed on the dicing tape, The adhesive layer contains an acrylic polymer having polymerizable (meth)acrylate units containing radical polymerizable carbon-carbon double bonds as monomer units in its molecule. The acrylic polymer contains the polymerizable (meth)acrylate units in an amount of 8 mol% to 35 mol% of the monomer units. The adhesive layer, when observed in cross-section with an electron microscope, has a phase-separated structure. The phase separation structure comprises a first phase containing radically polymerizable carbon-carbon double bonds and a second phase having a lower content of radically polymerizable carbon-carbon double bonds than the first phase and being separated from the first phase. A dicing die bond film in which the area ratio of the first phase in the cross-section is higher than 50%.

3. The invention comprises a dicing tape having a base layer and an adhesive layer superimposed on the base layer, and a die bond sheet superimposed on the dicing tape, The adhesive layer contains an acrylic polymer having polymerizable (meth)acrylate units containing radical polymerizable carbon-carbon double bonds as monomer units in its molecule. The acrylic polymer includes, as the monomer unit, a long-chain alkyl (meth)acrylate unit with 8 or more carbon atoms in the alkyl portion. In the acrylic polymer, the proportion of the long-chain alkyl (meth)acrylate units among the monomer units is 60 mol% or more and 82 mol% or less. The adhesive layer, when observed in cross-section with an electron microscope, has a phase-separated structure. The phase separation structure comprises a first phase containing radically polymerizable carbon-carbon double bonds and a second phase having a lower content of radically polymerizable carbon-carbon double bonds than the first phase and being separated from the first phase. A dicing die bond film in which the area ratio of the first phase in the cross-section is higher than 50%.

4. The acrylic polymer contains aliphatic alkyl (meth)acrylate units with 12 or more carbon atoms in the alkyl portion as the long-chain alkyl (meth)acrylate units. The dicing die bond film according to claim 3, wherein in the acrylic polymer, the proportion of the aliphatic alkyl (meth)acrylate units among the monomer units is 15 mol% or more and 40 mol% or less.

5. The invention comprises a dicing tape having a base layer and an adhesive layer superimposed on the base layer, and a die bond sheet superimposed on the dicing tape, The adhesive layer, when observed in cross-section with an electron microscope, has a phase-separated structure. The phase separation structure comprises a first phase containing radically polymerizable carbon-carbon double bonds and a second phase having a lower content of radically polymerizable carbon-carbon double bonds than the first phase and being separated from the first phase. The area ratio of the first phase in the cross-section is higher than 50%, A dicing die bond film in which the peel force between the adhesive layer and the die bond sheet satisfies the following formula (1): the peel force (A) before the dicing tape is cured by active energy rays and the peel force (B) after curing. (A) / (B)>7.0 Formula (1)

6. The invention comprises a dicing tape having a base layer and an adhesive layer superimposed on the base layer, and a die bond sheet superimposed on the dicing tape, The adhesive layer, when observed in cross-section with an electron microscope, has a phase-separated structure. The phase separation structure comprises a first phase containing radically polymerizable carbon-carbon double bonds and a second phase having a lower content of radically polymerizable carbon-carbon double bonds than the first phase and being separated from the first phase. The area ratio of the first phase in the cross-section is higher than 50%, A dicing die bond film in which the surface modulus of the adhesive layer after curing by active energy rays is greater than 30 MPa and less than 400 MPa.

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