Adhesive tape

Abstract

To provide an adhesive tape which sufficiently lowers adhesive force accompanied by irradiation with energy rays even after heating, and can maintain such characteristics as to prevent adhesion of a component contained in an adhesive layer, and has good expanding property.SOLUTION: An adhesive tape includes a base material, and an adhesive layer laminated on one surface of the base material, and is used for temporarily fixing a substrate, wherein the base material contains a polyester-based thermoplastic elastomer, and the adhesive layer contains a base resin (A) having adhesiveness, and a photopolymerization initiator (B) having a molecular weight of 300 or more and 2,000 or less.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an adhesive tape used for temporarily fixing substrates. [Background technology]

[0002] In the manufacturing process of a semiconductor device, adhesive tape is used for temporarily fixing a semiconductor substrate, and the adhesive tape includes a substrate and an adhesive layer provided on the substrate. In the manufacturing process of a semiconductor device, first, the outer periphery of the adhesive tape is fixed with a ring frame, and an adhesive layer is attached to the backside of a semiconductor substrate (semiconductor wafer). Next, the semiconductor substrate is cut in the thickness direction using a dicing saw to separate the substrate. Next, the adhesive layer is irradiated with ultraviolet light to harden it, thereby reducing its adhesive strength. Next, an expanding process is performed, in which the adhesive tape is stretched radially. Finally, the semiconductor elements obtained by the separation are picked up by pushing them up with a needle.

[0003] An example of an adhesive tape used in the manufacturing process of such semiconductor devices is the semiconductor processing sheet described in Patent Document 1. The semiconductor processing sheet described in Patent Document 1 is a sheet comprising an adhesive layer on a base film, and the gel fraction of the adhesive layer is 70% or more. The adhesive layer is formed from an energy beam-curable acrylic resin composition whose main component is an acrylic compound having an unsaturated double bond in the molecule.

[0004] It is also being considered to subject the semiconductor elements obtained by singulation to a heat resistance test before picking them up. In this case, not only the semiconductor elements but also the semiconductor processing sheet are subjected to the heat resistance test and heated. The heated semiconductor processing sheet is then irradiated with ultraviolet light. For this reason, the adhesive layer of the semiconductor processing sheet must maintain the property of reducing adhesive strength with ultraviolet light irradiation even after heating.

[0005] However, conventional adhesive tapes have a problem in that they do not maintain the above-mentioned properties sufficiently after heating. If the adhesive strength does not decrease sufficiently, there is a concern that poor pickup may occur or that components of the adhesive layer may adhere to the semiconductor element.

[0006] Furthermore, the semiconductor processing sheet after ultraviolet irradiation is subjected to an expanding process, and therefore is required to have heat resistance that prevents the sheet from loosening or significantly deforming even when heated.

[0007] However, conventional adhesive tapes lack sufficient heat resistance, causing the sheet to loosen when heated. This loosens the sheet, preventing the chip spacing from increasing in the subsequent expanding process, raising concerns about pickup failures during the semiconductor element pickup process. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-073056 Summary of the Invention [Problem to be solved by the invention]

[0009] The object of the present invention is to provide an adhesive tape that exhibits a sufficient decrease in adhesive strength upon irradiation with energy rays even after heating, maintains the property of components contained in the adhesive layer being less likely to adhere, and has good expandability. [Means for solving the problem]

[0010] These objects can be achieved by the present invention as set forth in (1) to (7) below. (1) An adhesive tape comprising a base material and an adhesive layer laminated on one surface of the base material, the adhesive tape being used to temporarily fix a substrate, the substrate contains a polyester-based thermoplastic elastomer, The adhesive layer is a base resin (A) having adhesive properties; a photopolymerization initiator (B) having a molecular weight of 300 or more and 2,000 or less; An adhesive tape comprising:

[0011] (2) The pressure-sensitive adhesive tape according to (1), wherein the photopolymerization initiator (B) contains an α-hydroxyketone compound.

[0012] (3) The pressure-sensitive adhesive tape according to (1) or (2), wherein the photopolymerization initiator (B) exhibits a weight loss rate of 20.0% or less after being heated in the atmosphere at a temperature of 150°C for 1 hour.

[0013] (4) The pressure-sensitive adhesive tape according to any one of (1) to (3) above, wherein the blending ratio of the photopolymerization initiator (B) to 100 parts by mass of the base resin (A) is 0.1 parts by mass or more and 20 parts by mass or less.

[0014] (5) The pressure-sensitive adhesive tape according to any one of (1) to (4), wherein the polyester-based thermoplastic elastomer is a block copolymer composed of a hard segment having an aromatic polyester and a soft segment having an aliphatic polyether.

[0015] (6) The pressure-sensitive adhesive tape according to (5), wherein the aromatic polyester is composed of butylene terephthalate units.

[0016] (7) The pressure-sensitive adhesive tape according to any one of (1) to (6) above, wherein the base resin (A) is a double-bond-introduced acrylic resin having an unsaturated double bond in a side chain. [Effects of the Invention]

[0017] According to the present invention, an adhesive tape can be obtained in which the adhesive strength is sufficiently reduced upon irradiation with energy rays even after heating, the components contained in the adhesive layer maintain their resistance to adhesion, and the tape has good expandability. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a vertical cross-sectional view showing an example of a semiconductor device manufactured using an adhesive tape according to an embodiment. [Figure 2] 1A to 1C are longitudinal cross-sectional views illustrating a method for manufacturing a semiconductor device using the adhesive tape according to the embodiment. [Figure 3] 1A to 1C are longitudinal cross-sectional views illustrating a method for manufacturing a semiconductor device using the adhesive tape according to the embodiment. [Figure 4] 1A to 1C are longitudinal cross-sectional views illustrating a method for manufacturing a semiconductor device using the adhesive tape according to the embodiment. [Figure 5] 1 is a longitudinal cross-sectional view showing a pressure-sensitive adhesive tape according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The pressure-sensitive adhesive tape according to the present invention will be described in detail below with reference to preferred embodiments shown in the accompanying drawings.

[0020] 1. Semiconductor Devices First, prior to describing the adhesive tape according to the embodiment, an example of a semiconductor device manufactured using the adhesive tape will be described.

[0021] 1 is a longitudinal cross-sectional view showing an example of a semiconductor device 10 manufactured using an adhesive tape according to an embodiment. In the following description, the upper side in FIG. 1 is referred to as "top" and the lower side as "bottom." In addition, in each drawing of the present application, the dimensional ratios in the left-right direction and the thickness direction may differ from the actual ratios.

[0022] The semiconductor device 10 shown in Figure 1 has a semiconductor chip 20 (semiconductor element), an interposer 30 (substrate) that supports the semiconductor chip 20, a plurality of conductive bumps 70 (terminals), and a molded portion 17 (sealing portion) that seals the semiconductor chip 20.

[0023] The interposer 30 is an insulating substrate and is made of various resin materials such as polyimide, epoxy resin, cyanate resin, bismaleimide triazine resin (BT resin), etc. The planar shape of the interposer 30 can be, for example, a quadrilateral such as a square or a rectangle.

[0024] On the upper surface of the interposer 30, terminals 41 made of a conductive metal material such as copper are provided in a predetermined shape.

[0025] Furthermore, a plurality of vias (through holes) and through wiring (not shown) are formed in the interposer 30 so as to penetrate the interposer 30 in the thickness direction.

[0026] Each bump 70 protrudes from the lower surface of the interposer 30. Each bump 70 is electrically connected to a terminal 41 via a through-wiring. Such a bump 70 is mainly made of a brazing material such as solder, silver brazing, copper brazing, or phosphorus copper brazing.

[0027] Terminals 41 provided on the interposer 30 are electrically connected to terminals 21 of the semiconductor chip 20 via connecting portions 81 .

[0028] An underfill material is filled in the gap between the semiconductor chip 20 and the interposer 30. The hardened underfill material forms a sealing layer 80. This sealing layer 80 improves the bonding strength between the semiconductor chip 20 and the interposer 30 and prevents the intrusion of foreign matter, moisture, and the like into the gap.

[0029] A molded portion 17 is provided on the upper side of the interposer 30 so as to cover the semiconductor chip 20 and the interposer 30. The molded portion 17 is made of a hardened semiconductor sealing material (sealant). By providing the molded portion 17, the semiconductor chip 20 is sealed, and the intrusion of foreign matter, moisture, etc. into the semiconductor chip 20 is prevented.

[0030] 1, the semiconductor chip 20 (semiconductor element) has a semiconductor chip body 23 (semiconductor element body) and terminals 21 provided on the lower surface of the semiconductor chip body 23. A circuit (not shown) is formed on the upper surface of the semiconductor chip body 23. Examples of materials that can be used to form the semiconductor chip body 23 include semiconductor materials such as Si, SiC, GaN, and Ga2O3.

[0031] 2. Manufacturing method of semiconductor device Next, an example of a method for manufacturing the semiconductor device 10 using the adhesive tape according to the embodiment will be described.

[0032] 2 to 4 are vertical cross-sectional views illustrating a method for manufacturing a semiconductor device 10 using the adhesive tape 100 according to the embodiment. In the following description, the upper side in each figure will be referred to as "upper" and the lower side will be referred to as "lower."

[0033] [1A] First, a semiconductor substrate 7 (semiconductor wafer) with a protective tape 500 attached thereto is prepared, as shown in Figure 2(a). The protective tape 500 is attached to a surface 71 of the semiconductor substrate 7, and protects a circuit formation region (not shown) included in the surface 71 from each of the processes described below. The circuit formation region (not shown) includes multiple individual circuits, and is divided into multiple regions in the processes described below.

[0034] [2A] Next, the upper surface of the protective tape 500 is fixed to a chuck table 600 of a back grinding device (back grinder). Then, the back surface 72 of the semiconductor substrate 7 shown in FIG. 2(b) is ground (back-grinded). This makes it possible to thin the semiconductor substrate 7. The thickness of the semiconductor substrate 7 after back-grinding is not particularly limited, but is, for example, about 40 to 600 μm.

[0035] [3A] Next, an adhesive tape 100 is prepared. The adhesive tape 100 shown in FIG. 2(c) has a base material 4 and an adhesive layer 2 laminated on the base material 4. Next, as shown in FIG. 2(c), an outer periphery 121 of the adhesive layer 2 of the adhesive tape 100 is fixed with a wafer ring 9. Then, the back surface 72 of a semiconductor substrate 7 (semiconductor wafer) is attached to a central portion 122 of the adhesive layer 2.

[0036] [4A] Next, the protective tape 500 is peeled off. By peeling off the protective tape 500, the surface 71 of the semiconductor substrate 7 is exposed, as shown in FIG.

[0037] [5A] Next, as shown in FIG. 3(a), the adhesive tape 100 to which the semiconductor substrate 7 is attached is placed on a dicer table 200.

[0038] [6A] Next, the semiconductor substrate 7 is cut into individual pieces using a dicing saw (blade) not shown (dicing process). As a result, a plurality of semiconductor chips 20 are obtained on the adhesive tape 100, as shown in FIG. 3(b). At this time, the adhesive tape 100 has a cushioning effect, so that cracks, chips, etc. in the semiconductor substrate 7 can be prevented. Furthermore, it is preferable that the cut marks made by the dicing saw reach the base material 4, as shown in FIG. 3(b). This allows the semiconductor substrate 7 to be reliably cut into individual pieces.

[0039] If necessary, cutting may be performed while supplying water to the semiconductor substrate 7. This makes it possible to prevent scattering of dust and overheating of the semiconductor substrate 7 that occurs when cutting the semiconductor substrate 7.

[0040] [7A] Next, a reliability test is performed on the semiconductor chips 20 obtained by the dicing process while they are still fixed to the adhesive tape 100. The reliability test may include a temperature cycle test, a high-temperature storage test, a high-temperature reverse bias test, a high-temperature and high-humidity reverse bias test, a thermal shock test, etc. All of these tests are types of heat resistance tests performed while applying heat H to the semiconductor chips 20, as shown in FIG. 3(c). For this reason, the adhesive tape 100 is required to maintain the adhesive strength necessary to fix the semiconductor chips 20 even at high temperatures. By performing the reliability test while the semiconductor chips 20 are fixed to the adhesive tape 100 in this way, the number of work steps associated with transporting the semiconductor chips 20 can be reduced compared to when the reliability test is performed after the pick-up process.

[0041] [8A] Next, as shown in FIG. 3(d), the adhesive tape 100 is irradiated with energy rays E such as ultraviolet rays (energy ray irradiation process). In the adhesive tape 100 irradiated with the energy rays E, the adhesive strength of the adhesive layer 2 is reduced. This allows the semiconductor chip 20 to be easily picked up in the pick-up process described later.

[0042] [9A] Next, the adhesive tape 100 with the semiconductor substrate 7 attached thereto is placed on an expanding table 300. The expanding table 300 includes an expanding stage 310 corresponding to the center of the semiconductor substrate 7 and a holder 320 corresponding to the outer periphery of the semiconductor substrate 7. In the pick-up process, as shown in FIG. 4(a), the expanding stage 310 is pushed upward against the holder 320 of the expanding table 300. This causes the adhesive tape 100 to be stretched radially, and gaps are formed between the semiconductor chips 20 obtained by singulation (expanding process).

[0043] Furthermore, with the adhesive tape 100, even after the heat resistance test, the slack of the sheet is kept sufficiently small and good expandability is maintained, thereby enabling the semiconductor substrates 7 to be stably separated into individual pieces.

[0044] [10A] Next, the adhesive tape 100 to which the expanding semiconductor substrate 7 has been attached is placed on a pickup table 400. Then, as shown in FIG. 4(b), the semiconductor chip 20 is picked up by a suction tool (not shown) such as a vacuum collet or air tweezers (pickup process). In the pick-up process, the semiconductor chip 20 may be pushed up from below by a needle (not shown).

[0045] Furthermore, the adhesive tape 100 maintains the adhesive strength reduction capability due to the energy ray irradiation treatment even after the heat resistance test. Therefore, in the pick-up treatment, the adhesive strength of the adhesive tape 100 is sufficiently reduced, allowing the semiconductor chip 20 to be smoothly picked up. In addition, the occurrence of problems such as components contained in the adhesive layer 2 adhering to the semiconductor chip 20 can be suppressed.

[0046] By going through the above steps [1A] to [10A], the individual semiconductor chips 20 are obtained. The individual semiconductor chips 20 are placed on, for example, the interposer 30 shown in FIG. 1. Then, the sealing layer 80 and the molded part 17 are provided. In this way, the semiconductor device 10 shown in FIG. 1 is obtained.

[0047] 3. Adhesive tape Fig. 5 is a vertical cross-sectional view showing an adhesive tape 100 according to an embodiment. In the following description, the upper side in Fig. 5 will be referred to as "top" and the lower side as "bottom."

[0048] The adhesive tape 100 is an adhesive tape used to temporarily fix a semiconductor substrate 7 (substrate), and as shown in FIG. 5, comprises a base material 4 and an adhesive layer 2. The adhesive layer 2 is laminated on the upper surface (one surface) of the base material 4. The base material 4 contains a polyester-based thermoplastic elastomer. The adhesive layer 2 contains a base resin (A) and a photopolymerization initiator (B). The base resin (A) imparts adhesiveness to the adhesive layer 2. The photopolymerization initiator (B) facilitates curing of the adhesive layer 2. The molecular weight of the photopolymerization initiator (B) is 300 or more and 2,000 or less.

[0049] With this configuration, even after a heat resistance test, the adhesive strength of the adhesive tape 100 can be sufficiently reduced by the energy ray irradiation treatment. This allows the pickup treatment to be carried out smoothly. Furthermore, the occurrence of problems such as components contained in the adhesive layer 2 adhering to the semiconductor chip 20 can be suppressed.

[0050] Furthermore, with the above-described configuration, the adhesive tape 100 can be obtained with sufficiently small sheet slack and good expandability even after a heat resistance test. Therefore, by performing an expanding process after a heat resistance test, the chip spacing is sufficiently widened to prevent contact between the chips and also to prevent problems such as peeling of the adhesive layer 2. This allows for stable pick-up of the semiconductor chips 20.

[0051] Furthermore, with the above-described configuration, since the adhesive tape 100 has good heat resistance, a reliability test involving heating can be performed on a plurality of semiconductor chips 20 while they are fixed to the adhesive tape 100. This eliminates the need to transport the semiconductor chips 20 individually, as was conventionally the case, and reduces the number of steps required for the reliability test, thereby improving the manufacturing efficiency of the semiconductor device 10. Each part of the adhesive tape 100 will be described in detail below.

[0052] 3.1. Base material The base material 4 is made of a polyester-based thermoplastic elastomer. The polyester-based thermoplastic elastomer has the properties of both rubber and engineering plastics, as well as heat resistance. Therefore, even when subjected to a heat resistance test, the slack of the sheet can be sufficiently reduced. This allows the pressure-sensitive adhesive tape 100 to maintain good expandability even when subjected to a heat resistance test.

[0053] A polyester-based thermoplastic elastomer is a copolymer whose molecular structure consists of a crystalline, relatively hard hard segment and an amorphous, relatively flexible soft segment. The monomer arrangement in the copolymer may be a block arrangement, a random arrangement, or an alternating arrangement, but a block arrangement is preferred. This allows for the production of a polyester-based thermoplastic elastomer that has a good balance of the properties of both rubber and engineering plastic.

[0054] The hard segment contains a polyester. This polyester may be an aliphatic polyester or an alicyclic polyester, but is preferably an aromatic polyester. This can particularly enhance the heat resistance of the polyester-based thermoplastic elastomer.

[0055] The aromatic polyester is composed of polyester units containing a structure derived from an aromatic dicarboxylic acid and a structure derived from an aliphatic diol or an alicyclic diol.

[0056] Examples of aromatic dicarboxylic acids include terephthalic acid and naphthalenedicarboxylic acid, with terephthalic acid being particularly preferred.

[0057] The aromatic polyester may contain a structure derived from another dicarboxylic acid. Examples of the other dicarboxylic acid include aromatic dicarboxylic acids such as diphenyldicarboxylic acid, isophthalic acid, and 5-sodium sulfoisophthalic acid, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid and tetrahydrophthalic anhydride, and aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, dimer acid, and hydrogenated dimer acid.

[0058] Examples of diols such as aliphatic diols or alicyclic diols include alkylene glycols having 2 to 8 carbon atoms. Specific examples include ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, and 1,4-cyclohexanedimethanol. Among these, ethylene glycol or 1,4-butanediol is particularly preferred. This can further improve the heat resistance of the polyester-based thermoplastic elastomer.

[0059] The aromatic polyester is composed of polyester units containing the above-described structures, and the polyester units are preferably butylene terephthalate units or butylene naphthalate units, more preferably butylene terephthalate units. The butylene terephthalate units are composed of a structure derived from terephthalic acid and a structure derived from 1,4-butanediol. The butylene naphthalate units are composed of a structure derived from 2,6-naphthalenedicarboxylic acid and a structure derived from 1,4-butanediol. These polyester units impart particularly good heat resistance and appropriate rigidity to polyester-based thermoplastic elastomers.

[0060] The soft segment comprises an aliphatic polyether, an aliphatic polyester, or an aliphatic polycarbonate, which imparts particularly good flexibility to the polyester-based thermoplastic elastomer.

[0061] Examples of aliphatic polyethers include poly(ethylene oxide) glycol, poly(propylene oxide) glycol, poly(tetramethylene oxide) glycol, poly(hexamethylene oxide) glycol, poly(trimethylene oxide) glycol, copolymers of ethylene oxide and propylene oxide, ethylene oxide adducts of poly(propylene oxide) glycol, and copolymers of ethylene oxide and tetrahydrofuran. Of these, poly(tetramethylene oxide) glycol or ethylene oxide adducts of poly(propylene oxide) glycol are preferably used as aliphatic polyethers. The use of these can impart better flexibility to polyester-based thermoplastic elastomers.

[0062] Examples of aliphatic polyesters include poly(ε-caprolactone), polyenantholactone, polycaprylolactone, and polybutylene adipate. Of these, poly(ε-caprolactone) and polybutylene adipate are preferred as aliphatic polyesters. Use of these can impart good heat resistance while maintaining the flexibility of the polyester-based thermoplastic elastomer.

[0063] The aliphatic polycarbonate preferably contains a residue of an aliphatic diol mainly having 2 to 12 carbon atoms. Examples of such aliphatic diols include ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 2,2-dimethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,9-nonanediol, and 2-methyl-1,8-octanediol.

[0064] Of these, the soft segment preferably contains an aliphatic polyether. This allows for a polyester-based thermoplastic elastomer with little change in elastic modulus with temperature change. As a result, a pressure-sensitive adhesive tape 100 with little change in appearance before and after a heat resistance test can be achieved.

[0065] The polyester-based thermoplastic elastomer is preferably a copolymer derived from terephthalic acid, 1,4-butanediol, and poly(tetramethylene oxide) glycol, which allows the pressure-sensitive adhesive tape 100 to have a particularly good appearance after a heat resistance test.

[0066] The proportion of structures derived from terephthalic acid in the structures derived from dicarboxylic acids contained in the polyester-based thermoplastic elastomer is preferably 40 mol % or more, more preferably 70 mol % or more, even more preferably 80 mol % or more, and particularly preferably 90 mol % or more, which can impart particularly good heat resistance to the pressure-sensitive adhesive tape 100.

[0067] Among the structures derived from the glycols contained in the polyester-based thermoplastic elastomer, the total proportion of the structure derived from 1,4-butanediol and the structure derived from poly(tetramethylene oxide) glycol is preferably 40 mol % or more, more preferably 70 mol % or more, even more preferably 80 mol % or more, and particularly preferably 90 mol % or more, which can impart particularly good flexibility to the pressure-sensitive adhesive tape 100.

[0068] Such a polyester-based thermoplastic elastomer is synthesized by copolymerizing a polymer constituting a hard segment and a polymer constituting a soft segment by a known method.

[0069] The number average molecular weight of the polymer that constitutes the hard segment is not particularly limited, but is preferably about 10,000 to 40,000. The number average molecular weight of the polymer that constitutes the soft segment is not particularly limited, but is preferably about 500 to 4,000.

[0070] The melting point of the polyester-based thermoplastic elastomer is not particularly limited, but is preferably 150° C. or higher and 250° C. or lower, and more preferably 170° C. or higher and 220° C. or lower. If the melting point of the polyester-based thermoplastic elastomer is within the above range, the heat resistance of the substrate 4 can be particularly improved. This makes it possible to realize an adhesive tape 100 that has particularly good expandability even after a heat resistance test.

[0071] If the melting point of the polyester-based thermoplastic elastomer is below the lower limit, the heat resistance of the substrate 4 may decrease. On the other hand, if the melting point of the polyester-based thermoplastic elastomer is above the upper limit, the flexibility of the substrate 4 may decrease, and the expandability of the pressure-sensitive adhesive tape 100 may decrease.

[0072] The melting point of the polyester-based thermoplastic elastomer is measured using a differential scanning calorimeter. The temperature rise rate during measurement is 20°C / min, and the melting peak temperature is taken as the melting point. The melting point of the polyester-based thermoplastic elastomer can be adjusted, for example, by changing the ratio of hard segments to soft segments.

[0073] Examples of commercially available polyester thermoplastic elastomers include the "Hytrel (registered trademark)" series manufactured by Toray Celanese and the "Pelprene (registered trademark)" series manufactured by Toyobo MC.

[0074] The substrate 4 may also contain various additives such as softeners such as mineral oil, fillers such as calcium carbonate, silica, talc, mica, and clay, antioxidants, light stabilizers, lubricants, dispersants, neutralizers, and colorants.

[0075] The substrate 4 may also contain, as an additive, a resin other than the polyester-based thermoplastic elastomer. In this case, the polyester-based thermoplastic elastomer may be alloyed with the other resin. Examples of the other resin include resins that are compatible with the polyester-based thermoplastic elastomer.

[0076] The content of the additive in the substrate 4 is preferably 30% by mass or less, and more preferably 1% by mass or more and 20% by mass or less.

[0077] The thickness of the substrate 4 is not particularly limited, but is preferably 30 μm or more and 200 μm or less, and more preferably 40 μm or more and 150 μm or less. When the thickness of the substrate 4 is within this range, the mechanical properties of the substrate 4 are optimized, and the substrate 4 can more reliably perform its functions. This allows the substrate 4 to have a sufficient expansion width during the expanding process. Furthermore, it is possible to prevent the substrate 4 from breaking during the dicing process, expanding process, pick-up process, etc.

[0078] The surface roughness Ra of the substrate 4 is, for example, preferably 0.2 μm or more and 2.0 μm or less, and more preferably 0.5 μm or more and 1.5 μm or less. When the surface roughness Ra of the substrate 4 is within this range, the adhesion between the substrate 4 and the adhesive layer 2 is improved. This makes it possible to prevent peeling between the substrate 4 and the adhesive layer 2 during the pick-up process.

[0079] 3.2. Adhesive layer The adhesive layer 2 has enough adhesiveness to support the semiconductor substrate 7 during the dicing process and to allow the semiconductor chip 20 to be picked up well during the pick-up process.

[0080] The adhesive layer 2 of the adhesive tape 100 according to this embodiment contains at least a base resin (A) and a photopolymerization initiator (B).

[0081] 3.2.1. Base Resin (A) The base resin (A) is an adhesive and provides the adhesive layer 2 with adhesiveness to the semiconductor substrate 7 .

[0082] Examples of the base resin (A) include various resins used as adhesives, such as acrylic resins, silicone resins, polyester resins, polyvinyl acetate resins, polyvinyl ether resins, styrene elastomer resins, polyisoprene resins, polyisobutylene resins, and urethane resins. One or more of these resins are used as the base resin (A). Of these, acrylic resins are preferably used as the base resin (A). Acrylic resins are useful because they have excellent heat resistance and are relatively easy and inexpensive to obtain.

[0083] In this specification, the acrylic resin refers to a polymer (homopolymer or copolymer) containing a (meth)acrylic acid ester as a monomer component. In addition, in this specification, (meth)acrylic acid includes both acrylic acid and methacrylic acid. Therefore, for example, (meth)acrylic acid ester includes both acrylic acid ester and methacrylic acid ester.

[0084] Examples of the (meth)acrylic acid ester include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, Examples thereof include (meth)acrylic acid alkyl esters such as isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, and octadecyl (meth)acrylate; (meth)acrylic acid cycloalkyl esters such as cyclohexyl (meth)acrylate; and (meth)acrylic acid aryl esters such as phenyl (meth)acrylate, and these may be used alone or in combination of two or more.

[0085] Among these, (meth)acrylic acid alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and octyl (meth)acrylate are preferably used. (Meth)acrylic acid alkyl esters have excellent heat resistance and are relatively easy and inexpensive to obtain.

[0086] The acrylic resin may contain a structure derived from a copolymerizable monomer for the purpose of improving properties such as cohesive strength and heat resistance.

[0087] Such copolymerizable monomers are not particularly limited, but examples thereof include hydroxyl group-containing monomers such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxyhexyl (meth)acrylate; epoxy group-containing monomers such as glycidyl (meth)acrylate; carboxyl group-containing monomers such as (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid; and acids such as maleic anhydride and itaconic anhydride. anhydride group-containing monomers, amide monomers such as (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-butyl(meth)acrylamide, N-methylol(meth)acrylamide, N-methylolpropane(meth)acrylamide, N-methoxymethyl(meth)acrylamide, N-butoxymethyl(meth)acrylamide, and N-hexyl(meth)acrylamide, aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, and t-butylaminoethyl (meth)acrylate, Examples of suitable monomers include cyano group-containing monomers, cyano group-containing monomers such as (meth)acrylonitrile, olefin-based monomers such as ethylene, propylene, isoprene, butadiene, and isobutylene, styrene-based monomers such as styrene, α-methylstyrene, and vinyltoluene, vinyl ester-based monomers such as vinyl acetate and vinyl propionate, vinyl ether-based monomers such as methyl vinyl ether and ethyl vinyl ether, halogen atom-containing monomers such as vinyl chloride and vinylidene chloride, alkoxy group-containing monomers such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate, and monomers having a nitrogen atom-containing ring, such as N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-vinylmorpholine, N-vinylcaprolactam, and N-(meth)acryloylmorpholine. These may be used alone or in combination of two or more.

[0088] The content of the copolymerizable monomer is preferably 1% by mass to 70% by mass, more preferably 2% by mass to 60% by mass, and even more preferably 5% by mass to 50% by mass, of all the monomer components constituting the acrylic resin, which allows the properties derived from the copolymerizable monomer to be appropriately imparted, thereby favorably modifying the properties of the acrylic resin.

[0089] The copolymerizable monomer may be contained at the end of the polymer main chain, in the middle of the polymer main chain, or both at the end and in the middle of the polymer main chain. The copolymerizable monomer may contain a polyfunctional monomer for the purpose of crosslinking between polymer main chains, etc.

[0090] Examples of polyfunctional monomers include 1,6-hexanediol (meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, glycerin di(meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, urethane (meth)acrylate, divinylbenzene, butyl di(meth)acrylate, and hexyl di(meth)acrylate, and these can be used alone or in combination of two or more.

[0091] Furthermore, ethylene-vinyl acetate copolymers and vinyl acetate polymers can also be used as components having the same function as the copolymerizable monomer.

[0092] Acrylic resins can be produced by polymerizing a single monomer component or a mixture of two or more monomer components, and the polymerization of these monomer components can be carried out using polymerization methods such as solution polymerization, emulsion polymerization, bulk polymerization, and suspension polymerization.

[0093] The acrylic resin may have a functional group (reactive functional group) that is reactive with a crosslinking agent or a photopolymerization initiator, such as a hydroxyl group or a carboxyl group. This allows the crosslinking agent or the photopolymerization initiator to be linked to the acrylic resin, thereby preventing the crosslinking agent or the photopolymerization initiator from leaking from the adhesive layer 2. As a result, the adhesive strength of the adhesive layer 2 after the energy ray irradiation treatment can be more reliably reduced.

[0094] 3.2.2. Double bond-introduced acrylic resin (A1) The base resin (A) may be a double-bond-introduced acrylic resin (A1). The double-bond-introduced acrylic resin (A1) is an acrylic resin having an unsaturated double bond in its side chain. The unsaturated double bond is not particularly limited as long as it is an unsaturated double bond, but is preferably a polymerizable carbon-carbon double bond (ethylenically unsaturated double bond) that can be three-dimensionally crosslinked by irradiation with energy rays E. Having a group containing such a polymerizable carbon-carbon double bond in its side chain more reliably forms three-dimensional crosslinks within the polymer main chain of the double-bond-introduced acrylic resin or between polymer main chains. This allows the base resin (A) to exhibit curability alone, thereby more reliably reducing the adhesive strength of the adhesive layer 2 after energy ray irradiation. In addition, the double-bond-introduced acrylic resin (A1) also has the effect of suppressing the detachment (elution) of the photopolymerization initiator (B). This effect allows the adhesive strength of the adhesive tape 100 to be sufficiently reduced by energy ray irradiation, even after a heat resistance test.

[0095] Examples of the group containing a polymerizable carbon-carbon double bond include a (meth)acryloyl group, a (meth)acryloyloxy group, a (meth)acryloylamino group, an allyl group, a 1-propenyl group, and a vinyl group.

[0096] The double bond-introduced acrylic resin (A1) is an acrylic resin having a main chain made of a polymer containing a (meth)acrylic acid ester as a main monomer unit, and a side chain bonded to the main chain and containing an unsaturated double bond.

[0097] The double bond-introduced acrylic resin (A1) is synthesized, for example, by a method including the steps of: obtaining an acrylic resin having a reactive functional group by copolymerizing one or more (meth)acrylic acid esters (A1-1) with one or more polymerizable compounds (A1-2) having a reactive functional group in the side chain; and reacting the acrylic resin with one or more compounds (A1-3) having a functional group reactive with the reactive functional group and an unsaturated double bond.

[0098] The proportion of the (meth)acrylic acid ester (A1-1) in the double bond-introduced acrylic resin (A1) is preferably from 50% by mass to 99% by mass, more preferably from 70% by mass to 95% by mass, based on the total mass of the monomer components constituting the double bond-introduced acrylic resin (A1).

[0099] The polymerizable compound (A1-2) is a polymerizable compound having a reactive functional group. Examples of the reactive functional group include a carboxyl group, a hydroxyl group, an amino group, a mercapto group, a cyclic acid anhydride group, and an epoxy group. Among these, when the reactive functional group is a carboxyl group, a hydroxyl group, an amino group, a mercapto group, or a cyclic acid anhydride group, the reactivity with a compound (A1-3) having, for example, an epoxy group or an isocyanate group as a functional group is good. Furthermore, when the reactive functional group is a cyclic acid anhydride group, the reactivity with a compound (A1-3) having, for example, a carboxyl group, a hydroxyl group, an amino group, a mercapto group, or a functional group is good.

[0100] Examples of the polymerizable compound (A1-2) having an epoxy group as a reactive functional group include glycidyl (meth)acrylate and 3,4-epoxycyclohexyl (meth)acrylate.

[0101] Examples of the polymerizable compound (A1-2) having a hydroxyl group as a reactive functional group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, and glycerin mono(meth)acrylate.

[0102] Examples of the polymerizable compound (A1-2) having a carboxyl group as a reactive functional group include (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid.

[0103] The acrylic resin may contain, in addition to the (meth)acrylic acid ester (A1-1) and the polymerizable compound (A1-2), other polymerizable compounds as monomer units, such as aromatic vinyl compounds such as styrene and vinyltoluene.

[0104] The compound (A1-3) is a compound having a functional group that reacts with the reactive functional group of the polymerizable compound (A1-2) and an unsaturated double bond.

[0105] Examples of the compound (A1-3) having a carboxyl group include (meth)acrylic acid, a dimer of (meth)acrylic acid, caprolactone-modified (meth)acrylic acid, a compound obtained by a ring-opening reaction between a (meth)acrylate having a hydroxyl group and a carboxylic acid anhydride, and β-acryloyloxyethyl hydrogen succinate. Examples of the compound (A1-3) having an isocyanate group include methacryloyloxyethyl isocyanate.

[0106] Examples of the compound (A1-3) having an epoxy group include glycidyl (meth)acrylate and allyl glycidyl ether.

[0107] 3.2.3. Physical properties of base resin (A) From the viewpoint of preventing contamination of the semiconductor substrate 7 and the like during the dicing process, it is preferable that the base resin (A) has a low content of low-molecular-weight substances. From this viewpoint, the weight-average molecular weight of the base resin (A) is preferably 300,000 to 5,000,000, more preferably 400,000 to 4,000,000, and even more preferably 500,000 to 1,500,000. If the weight-average molecular weight of the base resin (A) is below the lower limit, depending on the type of monomer component, the contamination prevention properties against the semiconductor substrate 7 and the like may be reduced, resulting in the risk of components contained in the adhesive layer 2 adhering to the semiconductor chip 20. On the other hand, if the weight-average molecular weight of the base resin (A) is above the upper limit, the viscosity of the composition for forming the adhesive layer 2 may be increased, which may increase the difficulty of manufacturing the adhesive tape 100. The weight-average molecular weight is calculated as a standard polystyrene equivalent by gel permeation chromatography (GPC).

[0108] The glass transition temperature Tg of the base resin (A) is preferably -70°C or higher and -10°C or lower, more preferably -50°C or higher and -20°C or lower, and even more preferably -45°C or higher and -25°C or lower. This allows the adhesive strength of the adhesive layer 2 to be optimized. If the glass transition temperature Tg is lower than the lower limit, the base resin (A) will not easily aggregate, which may result in the adhesive or the like adhering to the picked-up semiconductor chip 20. On the other hand, if the glass transition temperature Tg is higher than the upper limit, the adhesive strength of the adhesive layer 2 will be insufficient, which may result in defects during the dicing process.

[0109] The glass transition temperature Tg is appropriately adjusted depending on the monomer components constituting the base resin (A), the molecular weight, etc. The glass transition temperature Tg is measured using a differential scanning calorimeter (DSC) at a temperature rise rate of 0.1°C / min.

[0110] The unsaturated double bond equivalent weight of the base resin (A) is preferably 200 or more and 4000 or less, more preferably 250 or more and 3000 or less. The unsaturated double bond equivalent weight of the base resin (A) tends to reflect the adhesiveness, curability, and retention of the photopolymerization initiator (B). Therefore, if the unsaturated double bond equivalent weight is within the above range, an adhesive layer 2 that can more reliably suppress detachment of the photopolymerization initiator (B) can be obtained. Note that if the unsaturated double bond equivalent weight is below the above lower limit, the effect of suppressing detachment of the photopolymerization initiator (B) during a heat resistance test may be reduced, or the peelability of the adhesive layer 2 after energy ray irradiation treatment may be reduced. On the other hand, if the unsaturated double bond equivalent weight exceeds the above upper limit, the adhesiveness of the adhesive layer 2 may be insufficient.

[0111] The equivalent weight of the unsaturated double bonds of the base resin (A) is calculated by dividing the molecular weight by the number of unsaturated double bonds in the same molecule.

[0112] The content of the base resin (A) in the resin composition constituting the adhesive layer 2 is preferably 30% by mass or more and 90% by mass or less of the total solid content of the resin composition, and more preferably 40% by mass or more and 80% by mass or less.

[0113] 3.2.4. Photopolymerization initiator (B) When the base resin (A) is a double bond-introduced acrylic resin (A1), the photopolymerization initiator (B) facilitates the initiation of polymerization of the double bond-introduced acrylic resin (A1). When the base resin (A) contains a curable resin (C) described below, the photopolymerization initiator (B) also facilitates the initiation of polymerization of the curable resin (C). At least one of the base resin (A) and the curable resin (C) may react with the photopolymerization initiator (B) to initiate polymerization.

[0114] The photopolymerization initiator (B) is a compound having a molecular weight of 300 or more and 2,000 or less. If the molecular weight of the photopolymerization initiator (B) is within the above range, the photopolymerization initiator (B) is less likely to be detached from the adhesive layer 2 even after a heat resistance test. Therefore, by suppressing the detachment of the photopolymerization initiator (B), a sufficient amount of the photopolymerization initiator (B) is present in the adhesive layer 2 even after the heat resistance test. This allows the curing of the curable resin (C) and the like to be promoted when an energy ray irradiation treatment is performed. As a result, the adhesive strength of the adhesive tape 100 after the energy ray irradiation treatment can be sufficiently reduced.

[0115] Furthermore, as a result of investigations by the present inventors, it was found that when the substrate 4 adjacent to the adhesive layer 2 is made of a material with excellent flexibility, such as a polyester-based thermoplastic elastomer, the photopolymerization initiator (B) is likely to leach out from the heated adhesive layer 2 into the substrate 4. In contrast, when the molecular weight of the photopolymerization initiator (B) is within the above range, not only can the photopolymerization initiator (B) be prevented from detaching due to evaporation, but also from leaching out of the photopolymerization initiator (B) into the substrate 4. As a result, even when a material with excellent flexibility, such as a polyester-based thermoplastic elastomer, is used as the constituent material of the substrate 4, an adhesive layer 2 in which detachment of the photopolymerization initiator (B) is prevented can be realized. As a result, an adhesive layer 2 that exhibits excellent curability by energy ray irradiation treatment can be realized, even after a heat resistance test.

[0116] As mentioned above, the molecular weight of the photopolymerization initiator (B) is 300 or more and 2,000 or less, preferably 300 or more and 1,500 or less, and more preferably 300 or more and 1,000 or less. If the molecular weight of the photopolymerization initiator (B) is below the lower limit, the photopolymerization initiator (B) is likely to detach from the adhesive layer 2 in a heat resistance test. This makes it difficult for the adhesive layer 2 to cure even when subjected to an energy ray irradiation treatment. On the other hand, if the molecular weight of the photopolymerization initiator (B) is above the upper limit, the compatibility of the photopolymerization initiator (B) with other components decreases.

[0117] Examples of such photopolymerization initiators (B) include benzophenone-based compounds, acetophenone-based compounds, benzoin-based compounds, α-hydroxyketone-based compounds, α-aminoketone-based compounds, α-diketone-based compounds, α-diketone dialkyl acetal-based compounds, anthraquinone-based compounds, thioxanthone-based compounds, phosphine oxide-based compounds, and oxime ester-based compounds, and one or more of these may be used.

[0118] Among these, examples of the α-hydroxyketone compounds include oligo(2-hydroxy-2-methyl-1-(4-(1-methylvinyl)phenyl)propanone (ESACURE (registered trademark) ONE, manufactured by IGM Resins), 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)phenoxy]phenyl}-2-methylpropan-1-one (ESACURE KIP160, manufactured by IGM Resins), and 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)benzyl]phenyl}-2-methylpropan-1-one (Omnirad (registered trademark) 127, manufactured by IGM Resins BV).

[0119] Examples of α-aminoketone compounds include 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone (manufactured by IGM Resins BV, Omnirad 379EG) and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone-1 (manufactured by IGM Resins BV, Omnirad 369).

[0120] Examples of phosphine oxide compounds include 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (manufactured by IGM Resins BV, Omnirad TPO H) and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (manufactured by IGM Resins BV, Omnirad 819).

[0121] Examples of oxime ester compounds include 1-[4-(phenylthio)]-1,2-octanedione-2-(O-benzoyloxime) (manufactured by BASF Japan, IRGACURE (registered trademark) OXE-01) and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone-1-(O-acetyloxime) (manufactured by BASF Japan, IRGACURE OXE-02).

[0122] Other examples include 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenylbisimidazole (2-(2-chlorophenyl)-4,5-diphenylimidazole dimer) (manufactured by Hampford, B-CIM) and 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer (manufactured by Tokyo Chemical Industry Co., Ltd., BCTB).

[0123] Among these, an α-hydroxyketone compound is preferably used as the photopolymerization initiator (B). The α-hydroxyketone compound contributes to improving the curability of the adhesive layer 2 and has excellent compatibility with other components even though it has a high molecular weight, making it useful as the photopolymerization initiator (B).

[0124] Furthermore, the weight loss rate of the photopolymerization initiator (B) after heating in air at a temperature of 150°C for 1 hour is preferably 20.0% or less, more preferably 18.0% or less, and even more preferably 16.0% or less. When the weight loss rate of the photopolymerization initiator (B) is within the above range, the amount of evaporation of the photopolymerization initiator (B) during a heat resistance test can be sufficiently suppressed. As a result, even after the heat resistance test, a sufficient amount of the photopolymerization initiator (B) is present, and an adhesive layer 2 having excellent curability by energy ray irradiation treatment can be obtained.

[0125] The weight loss rate of the photopolymerization initiator (B) is measured as follows. First, weigh out approximately 1 g of photopolymerization initiator (B) and place it in an aluminum cup. Next, measure the weight of the photopolymerization initiator (B) using a precision balance and record it as the "weight before heat resistance test." Next, place the aluminum cup in an oven and heat it in the air at a temperature of 150°C for 1 hour. After heating is complete, remove the aluminum cup from the oven. Next, quickly measure the weight of the photopolymerization initiator (B) removed from the oven using a precision balance and record it as the "weight after heat resistance test." Then, calculate the weight loss rate (%) using the following formula.

[0126] (Weight loss rate) = {(Weight before heat resistance test) - (Weight after heat resistance test)} / (Weight before heat resistance test) × 100

[0127] Furthermore, a photopolymerization initiator other than the photopolymerization initiator (B) (hereinafter referred to as "another photopolymerization initiator") may be used in combination with the adhesive layer 2. The other photopolymerization initiator may be selected from, for example, the compounds described above, and may have a molecular weight of less than 300. By using such an other photopolymerization initiator in combination, for example, an effect of improving the curability can be obtained even when the adhesive layer 2 is made thick.

[0128] In this case, the content of the photopolymerization initiator (B) in the adhesive layer 2 is preferably higher than the content of the other photopolymerization initiators. This ensures the effects of the photopolymerization initiator (B). The ratio of the photopolymerization initiator (B) to the total amount of the photopolymerization initiator (B) and the other photopolymerization initiators is preferably 60% by mass or more, and more preferably 80% by mass or more.

[0129] The photopolymerization initiator (B) is preferably blended in an amount of 0.1 to 20 parts by mass, and more preferably 0.5 to 10 parts by mass, per 100 parts by mass of the base resin (A). By adjusting the blending amount of the photopolymerization initiator (B) as described above, the function of the photopolymerization initiator (B) can be more reliably exhibited and excess photopolymerization initiator (B) can be avoided.

[0130] If the blending ratio of the photopolymerization initiator (B) is below the lower limit, the blending amount of the photopolymerization initiator (B) will be insufficient, and curability may decrease when an energy ray irradiation treatment is performed. On the other hand, if the blending ratio of the photopolymerization initiator (B) is above the upper limit, the cohesive force of the adhesive layer 2 will decrease due to the excess photopolymerization initiator (B), and there is a risk that the adhesive will be transferred to the surface of the adherend after peeling from the adherend.

[0131] 3.2.5.Curing resin (C) The adhesive layer 2 may contain a curable resin (C). The curable resin (C) is a resin that has the ability to be cured by irradiation with energy rays E. The curable resin (C) may be a resin having a polymerizable functional group that polymerizes by irradiation with energy rays E, but is preferably a resin having a group containing a polymerizable carbon-carbon double bond that can be three-dimensionally crosslinked by irradiation with energy rays E. By containing such a curable resin (C), the adhesive strength of the adhesive layer 2 after the UV reaction (after irradiation with energy rays) can be further reduced.

[0132] On the other hand, when the base resin (A) is a double bond-introduced acrylic resin (A1), the adhesive layer 2 may or may not contain a curable resin (C).

[0133] Specific examples of the group containing a polymerizable carbon-carbon double bond include a (meth)acryloyl group, a (meth)acryloyloxy group, a (meth)acryloylamino group, an allyl group, a 1-propenyl group, and a vinyl group.

[0134] Examples of the curable resin (C) include low molecular weight compounds having at least two groups containing polymerizable carbon-carbon double bonds in the molecule that can be three-dimensionally crosslinked by irradiation with energy rays E. Specific examples of the compound include esters of (meth)acrylic acid and polyhydric alcohols such as trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, tetraethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, 1,4-butylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, and glycerin di(meth)acrylate; ester acrylate oligomers; cyanurate compounds having a carbon-carbon double bond-containing group such as 2-propenyl-di-3-butenyl cyanurate; tris(2-acryloxyethyl)isocyanurate; tris(2-methyl)isocyanurate; Examples of the acrylic acid acrylate include isocyanurate compounds having a carbon-carbon double bond-containing group, such as tris(1,3-diacryloxy-2-propyl-oxycarbonylamino-n-hexyl)isocyanurate, 2-hydroxyethylbis(2-acryloxyethyl)isocyanurate, bis(2-acryloxyethyl)2-[(5-acryloxyhexyl)-oxy]ethyl isocyanurate, tris(1,3-diacryloxy-2-propyl-oxycarbonylamino-n-hexyl)isocyanurate, tris(1-acryloxyethyl-3-methacryloxy-2-propyl-oxycarbonylamino-n-hexyl)isocyanurate, and tris(4-acryloxy-n-butyl)isocyanurate; commercially available oligoester acrylates; aromatic and aliphatic urethane acrylates; and epoxy acrylates such as bisphenol A epoxy acrylate, phenol novolac epoxy acrylate, and cresol novolac epoxy acrylate. These may be used alone or in combination of two or more.

[0135] Among these, it is preferable to contain at least one of an ester of (meth)acrylic acid and a polyhydric alcohol, a urethane acrylate, and an epoxy acrylate, and it is more preferable to contain a bisphenol A-type epoxy acrylate, which allows the curable resin (C) to be cured more reliably by irradiation with energy rays E.

[0136] The number of functional groups (the number of groups containing a polymerizable carbon-carbon double bond) per molecule of the curable resin (C) may be 2 or more, preferably 3 or more, and more preferably 4 or more. This can increase the reactivity of the curable resin (C), and in the adhesive layer 2, it is possible to more reliably achieve good releasability by energy ray irradiation treatment and suppression of defects in the pick-up treatment.

[0137] The weight-average molecular weight of the curable resin (C) is preferably smaller than that of the double bond-introduced acrylic resin (A). It is more preferably 100 to 15,000, and even more preferably 200 to 5,000. This ensures that the adhesive layer 2 has sufficient adhesive strength after UV reaction (after irradiation with energy rays). The weight-average molecular weight is measured by gel permeation chromatography (GPC) in terms of standard polystyrene.

[0138] The blending ratio of the curable resin (C) relative to 100 parts by mass of the base resin (A) is preferably 0 to 100 parts by mass, more preferably 15 to 90 parts by mass, even more preferably 20 to 70 parts by mass, and particularly preferably 50 to 70 parts by mass, which allows the curable resin (C) to more effectively exhibit its functions.

[0139] 3.2.6. Crosslinker (D) The resin composition constituting the adhesive layer 2 may contain a crosslinking agent (D). By containing the crosslinking agent (D), the adhesive layer 2 can be adjusted to have an appropriate hardness.

[0140] The crosslinking agent (D) is not particularly limited, but examples thereof include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, urea resin-based crosslinking agents, methylol-based crosslinking agents, chelate-based crosslinking agents, aziridine-based crosslinking agents, melamine-based crosslinking agents, polyvalent metal chelate-based crosslinking agents, acid anhydride-based crosslinking agents, polyamine-based crosslinking agents, carboxyl group-containing polymer-based crosslinking agents, etc. Among these, isocyanate-based crosslinking agents are preferred.

[0141] The isocyanate-based crosslinking agent is not particularly limited, but examples thereof include polyisocyanate compounds of polyvalent isocyanates, trimers of polyisocyanate compounds, trimers of isocyanate-terminated compounds obtained by reacting a polyisocyanate compound with a polyol compound, and blocked polyisocyanate compounds in which isocyanate-terminated urethane prepolymers are blocked with phenol, oximes, or the like.

[0142] Examples of polyisocyanates include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, diphenylmethane-4,4'-diisocyanate, diphenylmethane-2,4'-diisocyanate, 3-methyldiphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, 4,4'-diphenylether diisocyanate, 4,4'-[2,2-bis(4-phenoxyphenyl)propane]diisocyanate, and 2,2,4-trimethyl-hexamethylene diisocyanate. These may be used alone or in combination of two or more. Among these, at least one polyisocyanate selected from the group consisting of 2,4-tolylene diisocyanate, diphenylmethane-4,4'-diisocyanate, and hexamethylene diisocyanate is preferred.

[0143] The crosslinking agent (D) is preferably blended in an amount of 0.01 to 30 parts by mass, and more preferably 0.1 to 20 parts by mass, per 100 parts by mass of the base resin (A). By adjusting the blending amount of the crosslinking agent (D) as described above, the function exhibited by adding the crosslinking agent (D) to the resin composition can be reliably exhibited.

[0144] Plasticizers The adhesive layer 2 may contain a plasticizer. The plasticizer improves the flexibility of the adhesive layer 2. This allows the adhesive layer 2 to have excellent adhesion to, for example, the semiconductor substrate 7.

[0145] The plasticizer is not particularly limited, but examples thereof include phthalate ester plasticizers such as DOP (dioctyl phthalate), DBP (dibutyl phthalate), DIBP (diisobutyl phthalate), and DHP (diheptyl phthalate), aliphatic dibasic acid ester plasticizers such as DOA (di-2-ethylhexyl adipate), DIDA (diisodecyl adipate), and DOS (di-2-ethylhexyl sebacate), aromatic carboxylic acid ester plasticizers such as ethylene glycol benzoates, trimellitic acid ester plasticizers such as TOTM (trioctyl trimellitate), and adipate ester plasticizers, and these may be used alone or in combination of two or more.

[0146] The plasticizer is preferably blended in an amount of 0.1 to 5.0 parts by mass, more preferably 0.5 to 3.0 parts by mass, per 100 parts by mass of the base resin (A), thereby obtaining an adhesive layer 2 that maintains flexibility and has excellent adhesion to the semiconductor substrate 7.

[0147] 3.2.8.Other Ingredients The resin composition forming the adhesive layer 2 may contain one or more of the following other components: conductive materials, tackifiers, antioxidants, adhesion adjusters, fillers, colorants, flame retardants, softeners, antioxidants, surfactants, etc.

[0148] Among these, examples of tackifiers include rosin resins, terpene resins, coumarone resins, phenolic resins, aliphatic petroleum resins, aromatic petroleum resins, and aliphatic-aromatic copolymer petroleum resins, and these may be used alone or in combination of two or more.

[0149] 3.2.9. Thickness of adhesive layer, etc. The thickness of the adhesive layer 2 is not particularly limited, but is preferably 5 μm to 100 μm, more preferably 5 μm to 50 μm. By setting the thickness of the adhesive layer 2 within this range, it is possible to achieve an adhesive layer 2 that exhibits good adhesion to the semiconductor substrate 7 during the dicing process and good releasability during the pick-up process.

[0150] The adhesive layer 2 may be composed of a laminate (multilayer body) in which a plurality of layers composed of different resin compositions are laminated.

[0151] 4. Manufacturing method of adhesive tape Next, an example of a method for manufacturing the adhesive tape 100 will be described.

[0152] [1B] First, prepare the substrate 4. The method for producing the substrate 4 is not particularly limited, but examples thereof include common molding methods such as extrusion molding methods such as a calendar method, an inflation extrusion method, and a T-die extrusion method, and a wet casting method.

[0153] The upper surface of the substrate 4 may be previously subjected to a surface treatment such as corona treatment, chromic acid treatment, matte treatment, ozone exposure treatment, flame exposure treatment, high-voltage shock exposure treatment, ionizing radiation treatment, primer treatment, or anchor coat treatment, thereby improving the adhesion between the substrate 4 and the adhesive layer 2.

[0154] [2B] Next, adhesive layer 2 is formed on the upper surface of substrate 4. Adhesive layer 2 is formed by coating or spraying a liquid material made by dissolving a resin composition in a solvent to form a varnish on the upper surface of a film such as polyethylene terephthalate, then volatilizing the solvent to form a layer, and then transferring the layer to substrate 4.

[0155] The solvent is not particularly limited, but examples thereof include methyl ethyl ketone, acetone, toluene, ethyl acetate, dimethyl formaldehyde, etc., and one or more of these can be used in combination.

[0156] Furthermore, the liquid material can be applied or sprayed onto the substrate 4 using methods such as die coating, curtain die coating, gravure coating, comma coating, bar coating, and lip coating.

[0157] Thereafter, if necessary, a process for removing a part of the adhesive layer 2, a process for laminating a separator, etc. may be carried out. In this manner, the adhesive tape 100 is obtained.

[0158] 5. Effects of the above embodiment The pressure-sensitive adhesive tape 100 according to the embodiment includes a substrate 4 and a pressure-sensitive adhesive layer 2 laminated on one surface of the substrate 4, and is used to temporarily fix a semiconductor substrate 7 (substrate). The substrate 4 contains a polyester-based thermoplastic elastomer. The pressure-sensitive adhesive layer 2 contains a base resin (A) having adhesive properties and a photopolymerization initiator (B) having a molecular weight of 300 or more and 2,000 or less.

[0159] With this configuration, even after a heat resistance test, the adhesive strength of the adhesive tape 100 can be sufficiently reduced by the energy ray irradiation treatment. This allows the pickup treatment to be carried out smoothly. Furthermore, the occurrence of problems such as components contained in the adhesive layer 2 adhering to the semiconductor chip 20 can be suppressed.

[0160] Furthermore, since the substrate 4 contains a polyester-based thermoplastic elastomer, the pressure-sensitive adhesive tape 100 can maintain good expandability even when subjected to a heat resistance test. Furthermore, when the molecular weight of the photopolymerization initiator (B) is within the above range, it is possible to suppress desorption of the photopolymerization initiator (B) due to evaporation and desorption of the photopolymerization initiator (B) due to elution into the substrate 4. This makes it possible to realize an adhesive layer 2 in which desorption of the photopolymerization initiator (B) is suppressed, even when a polyester-based thermoplastic elastomer is used as a constituent material of the substrate 4. As a result, it is possible to realize an adhesive layer 2 that exhibits excellent curability by energy ray irradiation treatment, even after a heat resistance test.

[0161] Furthermore, since heating can be performed before the energy beam irradiation process, a reliability test involving heating can be performed while the semiconductor chips 20 are fixed to the adhesive tape 100. This eliminates the need to transport the semiconductor chips 20 individually, as was conventionally the case, and reduces the number of steps required for the reliability test, thereby improving the manufacturing efficiency of the semiconductor device 10.

[0162] The photopolymerization initiator (B) preferably contains an α-hydroxyketone compound. The α-hydroxyketone compound contributes to increasing the curability of the adhesive layer 2, and is also useful as the photopolymerization initiator (B) because it has excellent compatibility with other components even though it has a high molecular weight.

[0163] Furthermore, the photopolymerization initiator (B) preferably exhibits a weight loss rate of 20.0% or less after being heated in the air at a temperature of 150° C. for 1 hour.

[0164] According to this configuration, the amount of evaporation of the photopolymerization initiator (B) during the heat resistance test can be sufficiently suppressed, and as a result, even after the heat resistance test, the photopolymerization initiator (B) remains in sufficient quantity, and the adhesive layer 2 exhibits excellent curability upon energy ray irradiation treatment.

[0165] The blending ratio of the photopolymerization initiator (B) to 100 parts by mass of the base resin (A) is preferably 0.1 parts by mass or more and 20 parts by mass or less.

[0166] According to this configuration, the photopolymerization initiator (B) can more reliably exhibit its function, and excess photopolymerization initiator (B) can be avoided.

[0167] The polyester-based thermoplastic elastomer is preferably a block copolymer composed of a hard segment having an aromatic polyester and a soft segment having an aliphatic polyether.

[0168] This configuration provides a polyester-based thermoplastic elastomer that has particularly high heat resistance and particularly good flexibility, thereby providing a pressure-sensitive adhesive tape 100 that maintains particularly good expandability even after a heat resistance test.

[0169] The aromatic polyester is preferably composed of butylene terephthalate units.

[0170] According to this configuration, it is possible to realize a polyester-based thermoplastic elastomer that is endowed with particularly good heat resistance and appropriate rigidity.

[0171] The base resin (A) is preferably a double bond-introduced acrylic resin (A1) having an unsaturated double bond in the side chain.

[0172] According to this configuration, the base resin (A) alone exhibits curability, and the adhesive strength of the adhesive layer 2 after the energy ray irradiation treatment can be more reliably reduced. Due to this effect, the adhesive strength of the adhesive tape 100 can be sufficiently reduced by the energy ray irradiation treatment even after the heat resistance test.

[0173] Although the pressure-sensitive adhesive tape of the present invention has been described above, the present invention is not limited to the above-described embodiment.

[0174] For example, each layer of the pressure-sensitive adhesive tape of the present invention may contain a component other than the components described in the above embodiment. Furthermore, the pressure-sensitive adhesive tape of the present invention may have an optional layer added to the layer configuration described in the above embodiment. In this case, the location of the additional layer is not particularly limited, and may be on the upper surface of the pressure-sensitive adhesive layer, on the lower surface of the substrate, or between the pressure-sensitive adhesive layer and the substrate. Furthermore, the substrate may be composed of multiple layers.

[0175] Furthermore, the substrate to be temporarily fixed by the pressure-sensitive adhesive tape of the present invention is not limited to the above-mentioned semiconductor substrate (semiconductor wafer), and may be, for example, a glass substrate such as soda-lime glass, borosilicate glass, or quartz glass, a ceramic substrate such as alumina, silicon nitride, or titanium oxide, a resin substrate such as acrylic, polycarbonate, or rubber, a single crystal substrate such as quartz or sapphire, or a metal plate, etc. Furthermore, members such as chips obtained by dividing a wafer are also included in the substrate to be temporarily fixed by the pressure-sensitive adhesive tape. [Example]

[0176] Next, specific examples of the present invention will be described, but the present invention is not limited to the descriptions of these examples.

[0177] 6. Preparation of Adhesive Tape An adhesive tape was prepared using the following materials.

[0178] 6.1. Preparation of raw materials Table 1 shows the base resin, photopolymerization initiator, curable resin, and crosslinking agent used in preparing the adhesive layer.

[0179] The base resins a1-1, a1-2, a1-3, a1-4, and a2 shown in Table 1 are each an acrylic copolymer obtained by mixing at least two of butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, acrylic acid, 2-hydroxyethyl acrylate, N,N-dimethylacrylamide, and vinyl acetate, and solution-polymerizing the mixture in toluene using a conventional method.

[0180] As an example, the manufacturing method of base resin a1-1 will be described. First, an acrylic resin was prepared by copolymerizing butyl acrylate and acrylic acid. Next, this acrylic resin was reacted with glycidyl methacrylate (GMA). As a result, a double bond-introduced acrylic resin (base resin a1-1) was obtained, in which a structure derived from GMA was introduced as a side chain into the polymer main chain via an ester bond.

[0181] In addition, if each base resin is a double bond-introduced acrylic resin having an unsaturated double bond in the side chain, it is marked with a circle in Table 1, and if an unsaturated double bond is not introduced in the side chain, it is marked with an × in Table 1.

[0182] Table 1 also shows the main monomer component, the glass transition temperature Tg (theoretical Tg before the introduction of side-chain double bonds) of the backbone polymer, and the weight-average molecular weight Mw of each base resin. The main monomer component refers to the component with the highest mass content among all monomer components. Each base resin was synthesized by changing the blend and molecular weight of the monomer components so that these physical properties would achieve the values ​​shown in Table 1. The double bond equivalent weight of the double bond-introduced acrylic resins was in the range of 200 to 4000. Among the symbols representing the main monomer components, BA stands for butyl acrylate, and 2-EHA stands for 2-ethylhexyl acrylate.

[0183] Table 1 also shows the weight loss rates and molecular weights of the photopolymerization initiators b1-1, b1-2, b1-3, b1-4, b1-5, b2-1, and b2-2.

[0184] Furthermore, Table 1 shows the constituent materials of the substrate and the melting points of the constituent materials. Of these, the PBT elastomers all have hard segments containing butylene terephthalate units derived from terephthalic acid and 1,4-butanediol, and soft segments containing polyether units derived from aliphatic polyethers. The ratio of hard segments to soft segments is adjusted so that the melting points are as shown in Table 1.

[0185] In addition, the PBN-based elastomer has hard segments containing butylene naphthalate units derived from 2,6-naphthalenedicarboxylic acid and 1,4-butanediol, and soft segments containing polyether units derived from an aliphatic polyether.

[0186] [Table 1]

[0187] 6.2. Preparation of adhesive layer First, a liquid material was prepared by blending the raw materials for the adhesive layer shown in Tables 2 and 3 in a predetermined ratio. Next, this liquid material was bar-coated onto a polyethylene terephthalate film so that the thickness after drying would be the value shown in Tables 2 and 3. The resulting coating was dried at 80°C for 1 minute and transferred to the substrate shown in Tables 2 and 3 to obtain an adhesive layer.

[0188] Tables 2 and 3 show the constituent materials and thicknesses of the substrates used to prepare the adhesive tapes.

[0189] In Tables 2 and 3, examples corresponding to the present invention are designated as "Examples," and examples not corresponding to the present invention are designated as "Comparative Examples."

[0190] 7. Evaluation of adhesive tapes Next, the produced pressure-sensitive adhesive tapes were evaluated for the following items.

[0191] 7.1. Behavior of adhesive strength before and after UV irradiation The adhesive strength of the adhesive tape was measured while varying the presence or absence of heating and ultraviolet irradiation of the test piece as follows.

[0192] 7.1.1. Obtaining measurements at 23°C before UV exposure Strip-shaped test pieces measuring 25 mm in width and 300 mm in length were cut from the pressure-sensitive adhesive tapes of each Example and Comparative Example. Next, a 180-degree peel test was performed on the obtained test pieces in a test environment of 23±1°C and 50±5% relative humidity, and the peel strength of the test piece relative to the test plate was measured. A silicon wafer was used as the test plate. The 180-degree peel test involved attaching a test piece to the mirror surface of a silicon wafer, and then peeling it off in a 180-degree direction after 30 minutes, while measuring the peel strength at a peel rate of 300 mm / min. The mirror surface of the silicon wafer was a mirror-finished surface as specified in JIS H 0614:1996. The obtained peel strength was recorded as a measurement value at 23°C before UV irradiation. These measurements were then evaluated according to the following evaluation criteria. The evaluation results are shown in Tables 2 and 3.

[0193] A: The measured value at 23°C before UV exposure is 50cN / 25mm or more. B: The measured value at 23°C before UV exposure is 30cN / 25mm or more and less than 50cN / 25mm C: The measured value at 23°C before UV exposure is less than 30cN / 25mm

[0194] 7.1.2. Obtaining measurements after heating at 150°C for 30 minutes and irradiating with UV light A strip-shaped test piece having a width of 25 mm and a length of 300 mm was cut out from the adhesive tape of each Example and Comparative Example. Next, the obtained test piece was heated in the atmosphere at a temperature of 150°C for 30 minutes. Subsequently, the heated test piece was exposed to ultraviolet irradiance of 55 W / cm. 2 , UV irradiation amount: 200mJ / cm 2 The adhesive layer was cured by irradiating it with ultraviolet light under the above conditions. Next, a 180-degree peel test was performed on the test piece after ultraviolet irradiation under the above test environment, and the peel strength of the test piece against the test plate was measured. The obtained peel strength was recorded as the measured value "after heating at 150°C for 30 minutes and after ultraviolet irradiation." This measured value was then evaluated according to the following evaluation criteria. The evaluation results are shown in Tables 2 and 3.

[0195] A: The measured value after heating at 150°C for 30 minutes and irradiating with ultraviolet light is 30cN / 25mm or less. B: The measured value "after heating at 150°C for 30 minutes and irradiating with ultraviolet light" is more than 30cN / 25mm and 50cN / 25mm or less C: The measured value "after heating at 150°C for 30 minutes and irradiating with ultraviolet light" is more than 50cN / 25mm

[0196] 7.2. Whether or not adhesive layer components adhere after heating and UV irradiation After obtaining measurements "after heating at 150°C for 30 minutes and irradiating with ultraviolet light," the test plate (silicon wafer) was observed for the presence or absence of residue (components contained in the adhesive layer). The observation results were then evaluated according to the following evaluation criteria. The evaluation results are shown in Tables 2 and 3.

[0197] A: Little residue adhered (less than 5% of the outer circumference of the test piece) B: There is a little bit of residue (5% or more but less than 20% of the outer periphery of the test piece) C: A large amount of residue adheres (more than 20% of the outer circumference of the test piece)

[0198] 7.3.Expandability The adhesive tape of each Example and Comparative Example was fixed to a wafer ring. Next, a silicon wafer was diced using the adhesive tape, and the silicon wafer was then subjected to an expanding process. The adhesive tape subjected to the expanding process was checked for the presence or absence of expanding defects using an optical microscope. The results were evaluated according to the following evaluation criteria. The evaluation results are shown in Tables 2 and 3.

[0199] A: Few expansion defects (fracture of the substrate is less than 50% of the thickness) B: There are some expansion defects (the base material breaks at 50% or more but less than 100% of the thickness) C: Many expansion defects (one or more breaks throughout the thickness of the substrate)

[0200] 7.4.Appearance after heating The adhesive tapes of each Example and Comparative Example were fixed to a wafer ring and then heated in the atmosphere at a temperature of 150°C for 30 minutes. The adhesive tapes after heating were then visually inspected for any defects in appearance. The inspection results were then evaluated according to the following evaluation criteria. The evaluation results are shown in Tables 2 and 3.

[0201] A: Few poor appearances (sagging or wrinkles) B: Poor appearance (slack and wrinkles) C: Poor appearance (many loose or wrinkled)

[0202] [Table 2]

[0203] [Table 3]

[0204] From the results shown in Tables 2 and 3, the following was observed. By using a polyester thermoplastic elastomer as the raw material for the base material and a photopolymerization initiator with a molecular weight within a specified range as the raw material for the adhesive layer, the adhesive strength was able to be sufficiently reduced by irradiation with energy rays even after heat resistance testing.In addition, sagging and wrinkles after heating were well suppressed, and an adhesive tape with good expandability as a general characteristic was achieved. - As a result of being able to sufficiently reduce the adhesive strength, it was possible to prevent residue from the adhesive layer from adhering to the test plate. - When polyester-based thermoplastic elastomer was not used as the raw material for the base material, sufficient expandability was not obtained. When a photopolymerization initiator with a molecular weight within the specified range was not used as the raw material for the adhesive layer, the adhesive strength of the adhesive layer after heating and UV irradiation could not be sufficiently reduced. This is presumably because the photopolymerization initiator was released during heating. Better evaluation results were obtained by optimizing the glass transition temperature (Tg) and weight average molecular weight (Mw) of the base resin. By optimizing the melting point of the base material, we were able to prevent defects in the appearance after heating. [Explanation of symbols]

[0205] 2 Adhesive layer 4 Base material 7. Semiconductor substrate 9 wafer rings 10 Semiconductor devices 17 Mold section 20 Semiconductor chips 21 terminals 23 Semiconductor chip body 30 Interposer 41 terminals 70 Bump 71 Surface 72 Back side 80 Sealing layer 81 Connection 100 adhesive tape 121 Outer periphery 122 Central part 200 Dicer Table 300 Expandable Table 310 Extended Stage 320 Holding stand 400 Pickup Table 500 protective tape 600 chuck table E energy ray H fever

Claims

1. An adhesive tape used to temporarily fix a substrate, comprising a base material and an adhesive layer laminated on one surface of the base material, the substrate contains a polyester-based thermoplastic elastomer, The adhesive layer is a base resin (A) having adhesive properties; a photopolymerization initiator (B) having a molecular weight of 300 or more and 2,000 or less; An adhesive tape comprising:

2. The pressure-sensitive adhesive tape according to claim 1, wherein the photopolymerization initiator (B) contains an α-hydroxyketone compound.

3. 3. The pressure-sensitive adhesive tape according to claim 1, wherein the photopolymerization initiator (B) exhibits a weight loss rate of 20.0% or less after being heated in the atmosphere at a temperature of 150°C for 1 hour.

4. 3. The pressure-sensitive adhesive tape according to claim 1, wherein a blending ratio of the photopolymerization initiator (B) to 100 parts by mass of the base resin (A) is 0.1 parts by mass or more and 20 parts by mass or less.

5. 3. The pressure-sensitive adhesive tape according to claim 1, wherein the polyester-based thermoplastic elastomer is a block copolymer composed of a hard segment having an aromatic polyester and a soft segment having an aliphatic polyether.

6. The adhesive tape according to claim 5 , wherein the aromatic polyester is composed of butylene terephthalate units.

7. 3. The pressure-sensitive adhesive tape according to claim 1, wherein the base resin (A) is a double-bond-introduced acrylic resin having an unsaturated double bond in a side chain.

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