Adhesive tape for semiconductor processing and method for manufacturing semiconductor device

Abstract

[Problem] To suppress chipping caused by contact between chips, wherein the contact is due to the bending of the tape, when removing from a grinding table, with the use of a Bernoulli chuck, and then conveying to the next step an adhesive tape for semiconductor processing in which a chip group is held.　[Solution] An semiconductor processing adhesive tape (10) having a base material (11), a buffer layer (13) provided on one face side of the base material (11), and an adhesive layer (12) provided on the other face side of the base material (11), characterized in that the bending resistance of a laminate of the base material (11) and the buffer layer (13) is 68 mm or more.　

Description

Technical Field

[0001] The present invention relates to an adhesive tape for semiconductor processing. More specifically, it relates to an adhesive tape that is preferably used for temporarily holding semiconductor wafers and chips when manufacturing semiconductor devices using a method of forming grooves on the surface of a wafer or providing a modified region inside the wafer with a laser and then performing singulation of the wafer due to stress during back grinding of the wafer, and a method for manufacturing a semiconductor device using such an adhesive tape.

Background Art

[0002] As miniaturization and multifunctionalization of various electronic devices progress, semiconductor chips mounted on them are also required to be miniaturized and thinned. In order to thin the chips, it is common to grind the back surface of the semiconductor wafer to adjust the thickness. In addition, in order to obtain thinned chips, after forming grooves with a predetermined depth from the surface side of the wafer using a dicing blade, the wafer is fixed to a grinding table and grinding is performed from the back surface side of the wafer, and the wafer is singulated by grinding to obtain a chip, and a method called a dicing before grinding (DBG) process may be used. In DBG, since back grinding of the wafer and singulation of the wafer can be performed simultaneously, thin chips can be efficiently manufactured.

[0003] In recent years, as a modified example of the dicing before grinding method, a method has been proposed in which a modified region is provided inside the wafer with a laser and the wafer is singulated due to stress during back grinding of the wafer. Hereinafter, this method may be referred to as LDBG (Laser Dicing Before Grinding). In LDBG, since the wafer is cut in the crystal direction starting from the modified region, chipping can be reduced more than in the dicing before grinding method using a dicing blade. As a result, chips with excellent flexural strength can be obtained, and it can contribute to further thinning of the chips. Furthermore, compared with DBG in which grooves with a predetermined depth are formed on the surface of the wafer with a dicing blade, since there is no region where the wafer is scraped off with a dicing blade, that is, since the kerf width is extremely small, the chip yield is excellent.

[0004] Conventionally, during back-grinding of semiconductor wafers or during chip manufacturing using DBG or LDBG, it is common practice to apply a semiconductor processing adhesive tape called a backgrind sheet to the wafer surface to protect the circuits on the wafer surface and to hold the semiconductor wafer and semiconductor chip in place. The semiconductor processing adhesive tape side is fixed to the grinding table, and back-grinding is performed. After back-grinding, an adhesive tape with an adhesive layer is applied to the ground surface, or a protective film-forming tape is applied to form a protective film. Subsequently, the semiconductor processing adhesive tape applied to the wafer surface is peeled off after its adhesive strength is reduced by irradiation with energy rays such as ultraviolet light. Through this process, an adhesive layer or a protective film-forming layer is formed on the back surface of the chip.

[0005] Adhesive tapes used for semiconductor processing sometimes include laminated adhesive tapes comprising a base material, an adhesive layer, and a buffer layer. Specific examples of such adhesive tapes for semiconductor processing are described, for example, in Patent Document 1 (Japanese Patent Application Publication No. 2015-183008). The buffer layer is made of a soft resin and is provided to absorb vibrations generated during backside grinding of the wafer and to mitigate unevenness caused by foreign matter, thereby stably and flatly holding the wafer on the grinding table. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2015-183008 [Overview of the project] [Problems that the invention aims to solve]

[0007] Multiple individual semiconductor chips (sometimes referred to as "chip groups") are temporarily held on semiconductor processing adhesive tape and transported to the next process, such as the energy ray irradiation process or the pickup process. At this time, the surface on the semiconductor processing adhesive tape on which the chip groups are held is sucked by a jig called a chuck, and the semiconductor processing adhesive tape and the chip groups are removed from the grinding table and transported to the next process. Vacuum chucks that suck the surface on which the chip groups are held have been commonly used as such chucks. However, with vacuum chucks, the chuck comes into direct contact with the back surface of the chips, which can damage or contaminate the chips.

[0008] Therefore, the use of a jig called a Bernoulli chuck is being considered as an alternative to a vacuum chuck. As shown in Figure 2, the Bernoulli chuck 20 consists of an arc portion 22 on which a pad 21 is placed, and an arm portion 23 connected to the arc portion 22. The pad portion 21 utilizes the so-called Bernoulli effect to create a negative pressure region by spraying gas toward the chip group 24, thereby creating suction. As a result, the chip group 24 can be sucked without contact. It is expected that as a result, the chip group can be transported to the next process without damage or contamination. However, as the chips become thinner, the phenomenon called "chipping," in which the ends of the chips are damaged, has increased. After diligently investigating the cause of this, the inventors have obtained the following findings.

[0009] As described above, the Bernoulli chuck 20 consists of an arc portion 22 on which the pad 21 is placed, and an arm portion 23 connected to the arc portion 22. The arc portion 22 is slightly smaller than the outer circumference shape of the chip group 24 (i.e., the outer circumference shape of the wafer), and attracts the outer edge of the chip group 24. No suction force acts on the inner circumference. Therefore, when the chip group 24 is attracted by the Bernoulli chuck 20 and removed from the grinding table, the outer edge of the semiconductor processing adhesive tape 10 is attracted, but the inner circumference is not, and the inner circumference sags and curves due to the weight of the tape and chips (Figure 3). As a result, the divided chips come into contact with each other, causing chipping, which damages the ends of the chips.

[0010] In the DBG method, the chip spacing (kerf width) is relatively wide, so chip contact with chips does not occur frequently. However, in LDBG, the kerf width is virtually zero, so even a slight curvature of the tape causes the chips held on it to come into contact with each other, resulting in frequent chipping. Chipping is particularly likely to occur with extremely thin chips that have become thinner and have reduced flexural strength.

[0011] Based on this knowledge, the inventors conducted diligent research and discovered the possibility of reducing chipping by preventing the bending of the semiconductor processing adhesive tape, on which the chip group is held, when removing it from the grinding table using a Bernoulli chuck. Therefore, the inventors conceived of reducing chipping by controlling the rigidity and flexibility of the semiconductor processing adhesive tape within an appropriate range, and thus completed the present invention. In other words, the present invention aims to suppress the occurrence of chipping even when transporting a chip group using a Bernoulli chuck. [Means for solving the problem]

[0012] The gist of this invention, which aims to solve these problems, is as follows. (1) An adhesive tape comprising a base material, a buffer layer provided on one side of the base material, and an adhesive layer provided on the other side of the base material, An adhesive tape for semiconductor processing, wherein the rigidity of the laminate of the base material and buffer layer is 68 mm or more.

[0013] (2) The adhesive tape for semiconductor processing according to (1), wherein the Young's modulus of the substrate at 23°C is 1000 MPa or more.

[0014] (3) The semiconductor processing adhesive tape according to (1) or (2), wherein the thickness of the substrate is 80 μm or less.

[0015] (4) The semiconductor processing adhesive tape according to any one of (1) to (3), wherein the buffer layer is a cured product of a buffer layer forming composition containing an energy ray polymerizable compound.

[0016] (5) In the process of grinding the back surface of a semiconductor wafer having grooves formed on the surface of the semiconductor wafer or having a modified region formed on the semiconductor wafer, and singulating the semiconductor wafer into semiconductor chips by the grinding, a semiconductor processing adhesive tape according to any one of (1) to (4), which is adhered to and used on the surface of the semiconductor wafer.

[0017] (6) A step of adhering the semiconductor processing adhesive tape according to any one of (1) to (4) to the surface of a semiconductor wafer and cutting the adhesive tape along the outer periphery of the semiconductor wafer; A step of forming grooves from the surface side of the semiconductor wafer or forming a modified region inside the semiconductor wafer from the surface or back surface of the semiconductor wafer; A step of grinding the semiconductor wafer having the adhesive tape adhered to the surface and having the grooves or the modified region formed thereon from the back surface side, and singulating the semiconductor wafer into a plurality of chips starting from the grooves or the modified region; A step of supporting and transporting the semiconductor processing adhesive tape holding the plurality of singulated chips by a Bernoulli chuck; A step of peeling the adhesive tape from the plurality of chips; A method for manufacturing a semiconductor device comprising the above steps.

[0018] (7) Further, a method for manufacturing a semiconductor device according to (6), including a step of adhering a dicing die bonding tape to the back surface of a semiconductor chip. [Advantages of the Invention]

[0019] In the semiconductor processing adhesive tape according to the present invention, since the stiffness and flexibility of the tape are controlled within an appropriate range, even when the semiconductor processing adhesive tape holding a chip group is transported using a Bernoulli chuck, the tape does not bend, and the occurrence of chipping can be suppressed. [Brief Description of the Drawings]

[0020] [Figure 1] It is a schematic diagram showing the semiconductor processing adhesive tape of the present embodiment. [Figure 2] Shows the usage mode of the Bernoulli chuck. [Figure 3] It is a cross-sectional view of FIG. 2.

Embodiments for Carrying Out the Invention

[0021] Hereinafter, the adhesive tape for semiconductor processing according to the present invention will be specifically described. First, the main terms used in this specification will be explained. In this specification, for example, “(meth)acrylate” is used as a term indicating both “acrylate” and “methacrylate”, and the same applies to other similar terms.

[0022] “For semiconductor processing” means that it can be used in each process such as the conveyance of a semiconductor wafer, back grinding, dicing, and the pickup of semiconductor chips. The “front surface” of a semiconductor wafer refers to the surface on which a circuit is formed, and the “back surface” refers to the surface on which no circuit is formed. The singulation of a semiconductor wafer means dividing the semiconductor wafer into individual circuits to obtain semiconductor chips.

[0023] DBG refers to a method in which after forming a groove with a predetermined depth on the front surface side of a wafer, grinding is performed from the back surface side of the wafer, and the wafer is singulated by grinding. The groove formed on the front surface side of the wafer is formed by methods such as blade dicing, laser dicing, or plasma dicing. Also, LDBG is a modified example of DBG, and refers to a method in which a modified region is provided inside the wafer with a laser, and the wafer is singulated by stress or the like during back grinding of the wafer.

[0024] As shown in Figure 2, a Bernoulli chuck consists of an arc-shaped section 22 on which a pad 21 is positioned, and an arm section 23 connected to the arc-shaped section. Its specific configuration is not particularly limited, and various commercially available products can be used. For example, the arc-shaped section may be a closed circle (donut-shaped). The pad section 21 utilizes the so-called Bernoulli effect to create a negative pressure region by injecting gas toward the tip group, thereby creating suction. This allows for non-contact suction of the tip group.

[0025] Next, the configuration of each component of the semiconductor processing adhesive tape according to the present invention will be described in more detail. Note that the semiconductor processing adhesive tape according to the present invention may sometimes be simply referred to as "adhesive tape."

[0026] In this embodiment, as shown in Figure 1, the adhesive tape 10 refers to a laminate comprising a base material 11 and an adhesive layer 12. The adhesive tape 10 has a buffer layer 13 on the side of the base material 11 opposite to the adhesive layer 12. However, this does not prevent the inclusion of other constituent layers. For example, a primer layer may be formed on the surface of the base material on the adhesive layer side, and a release sheet may be laminated on the surface of the adhesive layer to protect the adhesive layer until use. The base material may be a single layer or a multilayer. The same applies to the adhesive layer and the buffer layer.

[0027] The rigidity of the laminate of the base material 11 and the buffer layer 13 is 68 mm or more, preferably 69 mm or more. There is no particular upper limit to the rigidity, but if the rigidity is too high, it may become difficult to peel off the adhesive tape 10, so it is preferably 150 mm or less, more preferably 100 mm or less, and more preferably 90 mm or less. By having the rigidity of the laminate of the base material 11 and the buffer layer 13 contained in the semiconductor processing adhesive tape 10 within the above range, even when the semiconductor processing adhesive tape 10 holding the chip group is supported by a Bernoulli chuck 20, the adhesive tape 10 is less likely to deform and sagging can be prevented. As a result, contact between chips is also reduced and chipping can be suppressed.

[0028] The stiffness is measured using the cantilever method. The laminate of the base material 11 and the buffer layer 13 is cut to a width of 20 mm and a length of 150 mm, and the stiffness is measured at 23°C and 50% RH using a cantilever-type stiffness meter (manufactured by TOYOSEIKI Corporation) (in accordance with JIS L1086). Since static electricity can affect the measured stiffness, static electricity is removed before measurement. Also, if the laminate is in roll form, the value in the MD (machine direction) direction is large, so the value in the CD (cross direction) direction is evaluated. Furthermore, when obtaining a laminate of the base material 11 and the buffer layer 13 from an adhesive tape 10 which is a laminate of the buffer layer 13 / base material 11 / adhesive layer 12, the stiffness is measured after removing the adhesive layer 12 with a solvent or the like.

[0029] In this embodiment, the adhesive tape is not particularly limited in terms of the material and physical properties of each component, as long as the rigidity and softness of the laminate of the base material 11 and the buffer layer 13 are within the above range. However, preferred configurations of each component of the semiconductor processing adhesive tape according to this embodiment will be described in more detail below.

[0030] [Base material 11] The base material 11 can be any type of resin film that has been conventionally used as a base material for semiconductor processing adhesive tapes, without any particular limitations. From the viewpoint of more securely holding wafers and chips, it is preferable that the Young's modulus of the base material 11 at 23°C is 1000 MPa or higher. If a base material with a Young's modulus of less than 1000 MPa is used, the holding performance of the adhesive tape on semiconductor wafers or semiconductor chips will decrease, making it difficult to suppress vibrations during back grinding, and increasing the likelihood of chipping or damage to semiconductor chips. Furthermore, when the semiconductor processing adhesive tape holding the chip group is lifted by a Bernoulli chuck, the inner circumference of the adhesive tape, where the suction force of the Bernoulli chuck does not act, sags and curves. As a result, the chips on the inner circumference of the adhesive tape may come into contact with each other, causing chipping. On the other hand, by setting the Young's modulus of the base material at 23°C to 1000 MPa or higher, the holding performance of the adhesive tape on semiconductor wafers or semiconductor chips is improved, vibrations during back grinding are suppressed, and chipping or damage to semiconductor chips can be prevented. In addition, since the curvature of the adhesive tape is suppressed, it becomes less likely for the chips to come into contact with each other, and chipping can be reduced. Furthermore, it becomes possible to reduce the stress when peeling the adhesive tape from the semiconductor chip, thereby preventing chip chipping or damage that may occur during tape removal. In addition, it is possible to improve the workability when attaching the adhesive tape to the semiconductor wafer. From this viewpoint, the Young's modulus of the substrate at 23°C is more preferably 1800 to 30000 MPa, and even more preferably 2500 to 6000 MPa.

[0031] The thickness of the substrate is not particularly limited, but is preferably 80 μm or less, more preferably 15 to 70 μm, and even more preferably 20 to 60 μm. By making the substrate thickness 80 μm or less, it becomes easier to control the peeling force of the adhesive tape. Also, by making it 15 μm or more, the substrate can more easily function as a support for the adhesive tape.

[0032] The material of the base material is not particularly limited as long as it satisfies the above physical properties, and various resin films can be used. Examples of base materials with a Young's modulus of 1000 MPa or more at 23°C include resin films such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyesters such as fully aromatic polyesters, polyimides, polyamides, polycarbonates, polyacetals, modified polyphenylene oxide, polyphenylene sulfide, polysulfones, polyether ketones, and biaxially oriented polypropylene.

[0033] Among these resin films, films containing one or more selected from polyester film, polyamide film, polyimide film, and biaxially oriented polypropylene film are preferred, more preferably containing polyester film, and even more preferably containing polyethylene terephthalate film.

[0034] Furthermore, the substrate may contain plasticizers, lubricants, infrared absorbers, ultraviolet absorbers, fillers, colorants, antistatic agents, antioxidants, catalysts, etc., to the extent that they do not impair the effects of the present invention. The substrate may also be transparent or opaque, and may be colored or vapor-deposited as desired.

[0035] Furthermore, at least one surface of the substrate may be subjected to an adhesive treatment such as corona treatment to improve adhesion with at least one of the buffer layer and the adhesive layer. The substrate may also consist of the resin film described above and a primer layer coated on at least one surface of the resin film.

[0036] The primer layer forming composition is not particularly limited, but examples include compositions containing polyester resins, urethane resins, polyester-urethane resins, acrylic resins, etc. The primer layer forming composition may optionally contain crosslinking agents, photopolymerization initiators, antioxidants, plasticizers, fillers, rust inhibitors, pigments, dyes, etc.

[0037] The thickness of the primer layer is preferably 0.01 to 10 μm, more preferably 0.03 to 5 μm. In this embodiment, the thickness of the primer layer is small compared to the thickness of the substrate, so the thickness of the resin film with the primer layer is substantially the same as the thickness of the substrate. Furthermore, because the material of the primer layer is soft, it has little effect on the Young's modulus, and the Young's modulus of the substrate is substantially the same as that of the resin film, even when a primer layer is present.

[0038] For example, the Young's modulus of a substrate can be controlled by selecting the resin composition, adding plasticizers, and the stretching conditions during resin film manufacturing. Specifically, when polyethylene terephthalate film is used as the substrate, the Young's modulus of the substrate tends to decrease as the proportion of ethylene in the copolymer increases. Also, the Young's modulus of the substrate tends to decrease as the amount of plasticizer added to the resin composition constituting the substrate increases.

[0039] [Adhesive layer 12] The adhesive layer 12 is not particularly limited as long as it has adequate pressure-sensitive adhesion at room temperature, but it is preferable that its shear storage modulus at 23°C is 0.05 to 0.50 MPa. The surface of a semiconductor wafer is usually uneven, with circuits and the like formed on it. When the shear storage modulus of the adhesive layer is within the above range, it becomes possible to ensure sufficient contact between the uneven wafer surface and the adhesive layer when applying adhesive tape to the uneven wafer surface, and to properly exhibit the adhesive properties of the adhesive layer. Therefore, it becomes possible to reliably fix the adhesive tape to the semiconductor wafer and to properly protect the wafer surface during backside grinding. From these viewpoints, it is more preferable that the shear storage modulus of the adhesive layer is 0.12 to 0.35 MPa. Note that, if the adhesive layer is formed from an energy-ray curable adhesive, the shear storage modulus of the adhesive layer refers to the shear storage modulus before curing by energy-ray irradiation.

[0040] The shear storage modulus can be measured by the following method. A sample is prepared by punching out a circle with a diameter of 7.9 mm from an adhesive layer with a thickness of approximately 0.5 to 1 mm. The elastic modulus of the sample is measured using a Rheometric ARES dynamic viscoelasticity analyzer at a frequency of 1 Hz and a temperature range from -30°C to 150°C at a heating rate of 3°C / min. The elastic modulus at a measurement temperature of 23°C is taken as the shear storage modulus at 23°C.

[0041] The thickness of the adhesive layer is preferably less than 100 μm, more preferably 5 to 80 μm, and even more preferably 10 to 70 μm. Making the adhesive layer this thin suppresses the generation of tape debris when the adhesive tape is cut, and makes it easier to prevent cracks in the semiconductor chip that occur during backside grinding.

[0042] The adhesive layer is formed from, for example, an acrylic adhesive, a urethane adhesive, a rubber adhesive, a silicone adhesive, etc., but an acrylic adhesive is preferred. Furthermore, it is preferable that the adhesive layer be formed from an energy-ray curable adhesive. By forming the adhesive layer from an energy-ray curable adhesive, it becomes possible to set the shear storage modulus at 23°C within the above range before curing by energy irradiation, and to easily set the peel force to 1000 mN / 50 mm or less after curing.

[0043] The following describes specific examples of adhesives, but these are non-limiting examples, and the adhesive layer in the present invention should not be interpreted as being limited to these examples.

[0044] [Adhesive composition] As the energy-ray curable adhesive that forms the adhesive layer, for example, an energy-ray curable adhesive composition containing an energy-ray curable compound other than the adhesive resin (hereinafter also referred to as "Type X adhesive composition") can be used in addition to a non-energy-ray curable adhesive resin (also referred to as "adhesive resin I"). Furthermore, an adhesive composition containing an energy-ray curable adhesive resin (hereinafter also referred to as "adhesive resin II") in which an unsaturated group is introduced into the side chain of a non-energy-ray curable adhesive resin as the main component, and which does not contain any energy-ray curable compounds other than the adhesive resin (hereinafter also referred to as "Type Y adhesive composition") may also be used.

[0045] Furthermore, as an energy-ray curable adhesive, a combination of type X and type Y, that is, an energy-ray curable adhesive composition (hereinafter also referred to as "XY-type adhesive composition") which includes an energy-ray curable adhesive resin II as well as an energy-ray curable compound other than the adhesive resin, may also be used.

[0046] Among these, it is preferable to use an XY-type adhesive composition. By using an XY-type composition, it is possible to have sufficient adhesive properties before curing, while keeping the peel strength to the semiconductor wafer sufficiently low after curing.

[0047] However, the adhesive may be formed from a non-energy-ray curable adhesive composition that does not harden when irradiated with energy rays. The non-energy-ray curable adhesive composition contains at least a non-energy-ray curable adhesive resin I, but does not contain the above-mentioned energy-ray curable adhesive resin II or energy-ray curable compound.

[0048] In the following explanation, "adhesive resin" is used as a term referring to either or both of the above-mentioned adhesive resins I and II. Specific examples of adhesive resins include acrylic resins, urethane resins, rubber resins, and silicone resins, but acrylic resins are preferred. The following provides a more detailed explanation of acrylic adhesives, specifically those using acrylic resins as the adhesive resin.

[0049] Acrylic resins utilize acrylic polymers. Acrylic polymers are obtained by polymerizing monomers containing at least alkyl (meth)acrylate, and include constituent units derived from alkyl (meth)acrylate. Examples of alkyl (meth)acrylates include alkyl groups with 1 to 20 carbon atoms, and the alkyl group may be linear or branched. Specific examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, and dodecyl (meth)acrylate. Alkyl (meth)acrylates may be used alone or in combination of two or more types.

[0050] Furthermore, from the viewpoint of improving the adhesive strength of the adhesive layer, the acrylic polymer preferably contains constituent units derived from alkyl (meth)acrylate, in which the alkyl group has 4 or more carbon atoms. The number of carbon atoms in the alkyl (meth)acrylate is preferably 4 to 12, and more preferably 4 to 6. In addition, the alkyl (meth)acrylate in which the alkyl group has 4 or more carbon atoms is preferably an alkyl acrylate.

[0051] In the acrylic polymer, the content of alkyl (meth)acrylate having 4 or more carbon atoms in the alkyl group is preferably 40 to 98 parts by mass, more preferably 45 to 95 parts by mass, and even more preferably 50 to 90 parts by mass, per 100 parts by mass of the total amount of monomers constituting the acrylic polymer (hereinafter also simply referred to as "total amount of monomers").

[0052] The acrylic polymer is preferably a copolymer that includes structural units derived from alkyl(meth)acrylate having 4 or more carbon atoms in the alkyl group, as well as structural units derived from alkyl(meth)acrylate having 1 to 3 carbon atoms in the alkyl group, in order to adjust the elastic modulus and adhesive properties of the adhesive layer. The alkyl(meth)acrylate is preferably an alkyl(meth)acrylate having 1 or 2 carbon atoms, more preferably methyl(meth)acrylate, and most preferably methyl methacrylate. In the acrylic polymer, the content of alkyl(meth)acrylate having 1 to 3 carbon atoms in the alkyl group is preferably 1 to 30 parts by mass, more preferably 3 to 26 parts by mass, and even more preferably 6 to 22 parts by mass, per 100 parts by mass of the total amount of monomer.

[0053] It is preferable that the acrylic polymer has structural units derived from functional group-containing monomers in addition to the alkyl (meth)acrylate-derived structural units described above. Examples of functional groups in the functional group-containing monomers include hydroxyl groups, carboxyl groups, amino groups, epoxy groups, etc. The functional group-containing monomer can react with the crosslinking agent described later to become a crosslinking starting point, or react with the unsaturated group-containing compound to introduce unsaturated groups into the side chains of the acrylic polymer.

[0054] Examples of functional group-containing monomers include hydroxyl group-containing monomers, carboxyl group-containing monomers, amino group-containing monomers, and epoxy group-containing monomers. In this embodiment, hydroxyl group-containing monomers, carboxyl group-containing monomers, amino group-containing monomers, epoxy group-containing monomers, etc., may be used individually or in combination of two or more. Among these, the use of hydroxyl group-containing monomers and carboxyl group-containing monomers is preferred, and the use of hydroxyl group-containing monomers is more preferred.

[0055] Examples of hydroxyl group-containing monomers include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; and unsaturated alcohols such as vinyl alcohol and allyl alcohol.

[0056] Examples of monomers containing a carboxyl group include ethylenically unsaturated monocarboxylic acids such as (meth)acrylic acid and crotonic acid; ethylenically unsaturated dicarboxylic acids such as fumaric acid, itaconic acid, maleic acid, and citraconic acid, and their anhydrides, as well as 2-carboxyethyl methacrylate.

[0057] The content of functional group-containing monomers is preferably 1 to 35 parts by mass, more preferably 3 to 32 parts by mass, and even more preferably 6 to 30 parts by mass, based on 100 parts by mass of the total amount of monomers constituting the acrylic polymer. In addition to the above, the acrylic polymer may also contain monomer-derived structural units copolymerizable with the above acrylic monomers, such as styrene, α-methylstyrene, vinyltoluene, vinyl formate, vinyl acetate, acrylonitrile, and acrylamide.

[0058] The above-mentioned acrylic polymer can be used as a non-energy ray curable adhesive resin I (acrylic resin). Furthermore, an example of an energy ray curable acrylic resin is obtained by reacting the functional groups of the above-mentioned acrylic polymer I with a compound having a photopolymerizable unsaturated group (also called an unsaturated group-containing compound).

[0059] Unsaturated group-containing compounds are compounds that have both substituents that can bond to the functional groups of acrylic polymers and photopolymerizable unsaturated groups. Examples of photopolymerizable unsaturated groups include (meth)acryloyl groups, vinyl groups, allyl groups, and vinylbenzyl groups, with (meth)acryloyl groups being preferred. Examples of substituents that can bond to functional groups in unsaturated group-containing compounds include isocyanate groups and glycidyl groups. Therefore, examples of unsaturated group-containing compounds include (meth)acryloyloxyethyl isocyanate, (meth)acryloyl isocyanate, and glycidyl (meth)acrylate.

[0060] Furthermore, the unsaturated group-containing compound preferably reacts with some of the functional groups of the acrylic polymer. Specifically, it is preferable to react 50 to 98 mol% of the functional groups of the acrylic polymer with the unsaturated group-containing compound, and more preferably 55 to 93 mol%. In this way, in the energy-ray curable acrylic resin, some of the functional groups remain without reacting with the unsaturated group-containing compound, making it easier to crosslink with the crosslinking agent. The weight-average molecular weight (Mw) of the acrylic resin is preferably 300,000 to 1,600,000, more preferably 400,000 to 1,400,000, and even more preferably 500,000 to 1,200,000.

[0061] (Energy ray curable compound) As energy-ray curable compounds contained in type X or type XY adhesive compositions, monomers or oligomers having an unsaturated group in the molecule and capable of polymerization curing by energy irradiation are preferred. Examples of such energy-ray curable compounds include polyvalent (meth)acrylate monomers such as trimethylolpropane tri(meth)acrylate, pentaerythritol (meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butylene glycol di(meth)acrylate, and 1,6-hexanediol (meth)acrylate, as well as oligomers such as urethane (meth)acrylate, polyester (meth)acrylate, polyether (meth)acrylate, and epoxy (meth)acrylate.

[0062] Among these, urethane (meth)acrylate oligomers are preferred from the viewpoint of having a relatively high molecular weight and not easily reducing the shear storage modulus of the adhesive layer. The molecular weight (weight-average molecular weight in the case of oligomers) of the energy ray curable compound is preferably 100 to 12000, more preferably 200 to 10000, even more preferably 400 to 8000, and particularly preferably 600 to 6000.

[0063] In the X-type adhesive composition, the content of the energy-ray curable compound is preferably 40 to 200 parts by mass, more preferably 50 to 150 parts by mass, and even more preferably 60 to 90 parts by mass, per 100 parts by mass of the adhesive resin. On the other hand, in the XY-type adhesive composition, the content of the energy-ray curable compound is preferably 1 to 30 parts by mass, more preferably 2 to 20 parts by mass, and even more preferably 3 to 15 parts by mass, per 100 parts by mass of the adhesive resin. In the XY-type adhesive composition, since the adhesive resin is energy-ray curable, it is possible to sufficiently reduce the peel strength after energy irradiation even with a small content of the energy-ray curable compound.

[0064] (Crosslinking agent) The adhesive composition preferably further contains a crosslinking agent. The crosslinking agent crosslinks the adhesive resins by reacting with, for example, functional groups derived from functional group-containing monomers of the adhesive resin. Examples of crosslinking agents include isocyanate-based crosslinking agents such as tolylene diisocyanate, hexamethylene diisocyanate, and their adducts; epoxy-based crosslinking agents such as ethylene glycol glycidyl ether; aziridine-based crosslinking agents such as hexa[1-(2-methyl)-aziridinyl]triphosphotriazine; and chelate-based crosslinking agents such as aluminum chelate. These crosslinking agents may be used individually or in combination of two or more.

[0065] Among these, isocyanate-based crosslinking agents are preferred from the viewpoint of increasing cohesive force and improving adhesiveness, as well as from the viewpoint of ease of availability. The amount of crosslinking agent to be blended is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 7 parts by mass, and even more preferably 0.05 to 4 parts by mass, per 100 parts by mass of adhesive resin, from the viewpoint of promoting the crosslinking reaction.

[0066] (Photopolymerization initiator) Furthermore, if the adhesive composition is energy ray curable, it is preferable that the adhesive composition further contains a photopolymerization initiator. By including a photopolymerization initiator, the curing reaction of the adhesive composition can proceed sufficiently even with relatively low energy rays such as ultraviolet light.

[0067] Examples of photopolymerization initiators include benzoin compounds, acetophenone compounds, acyl phosphinoxide compounds, titanocene compounds, thioxanthone compounds, peroxide compounds, and photosensitizers such as amines and quinones. More specifically, examples include 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzylphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyrolnitrile, dibenzyl, diacetyl, 8-chloranthraquinone, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, and 2,2-dimethoxy-2-phenylacetophenone.

[0068] These photopolymerization initiators may be used individually or in combination of two or more. The amount of photopolymerization initiator added is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 5 parts by mass, and even more preferably 0.05 to 5 parts by mass, per 100 parts by mass of adhesive resin.

[0069] (Other additives) The adhesive composition may contain other additives as long as they do not impair the effects of the present invention. Examples of other additives include antistatic agents, antioxidants, plasticizers, fillers, rust inhibitors, pigments, dyes, and the like. When these additives are included, the amount of additive is preferably 0.01 to 6 parts by mass per 100 parts by mass of the adhesive resin.

[0070] Furthermore, the adhesive composition may be further diluted with an organic solvent to provide a solution of the adhesive composition, from the viewpoint of improving its applicability to substrates, buffer layers, and release sheets. Examples of organic solvents include methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexane, n-hexane, toluene, xylene, n-propanol, and isopropanol. These organic solvents may be the same organic solvents used during the synthesis of the adhesive resin, or one or more organic solvents other than those used during synthesis may be added to ensure uniform application of the adhesive composition solution.

[0071] [Buffer layer 13] The adhesive tape 10 according to this embodiment has a buffer layer 13. An adhesive layer 12 is provided on one side of the base material 11, and a buffer layer 13 is provided on the other side of the base material 11.

[0072] The buffer layer relieves stress during back-side grinding of the semiconductor wafer, preventing cracks and chips from occurring. When adhesive tape is attached to the semiconductor wafer and cut along the outer edge, the semiconductor wafer is placed on the grinding table via the adhesive tape and back-side grinding is performed. The presence of a buffer layer as a constituent layer of the adhesive tape makes it easier to properly hold the semiconductor wafer on the grinding table. Furthermore, even if there is foreign matter on the grinding table, the deformation of the buffer layer can absorb the irregularities of the foreign matter, allowing the wafer to be ground to a smooth and uniform thickness.

[0073] The thickness of the buffer layer is preferably 1 to 100 μm, more preferably 5 to 80 μm, and even more preferably 10 to 60 μm. By setting the thickness of the buffer layer within the above range, the buffer layer can appropriately relieve stress during backside grinding.

[0074] The buffer layer is not limited in composition, but from the viewpoint of easy control of viscoelasticity, it is preferably a cured product of a buffer layer forming composition containing an energy ray polymerizable compound. The following describes, in order, each component contained in the layer formed from the buffer layer-forming composition containing an energy ray polymerizable compound.

[0075] <Layer formed from a buffer layer-forming composition containing an energy-polymerizable compound> A buffer layer-forming composition containing an energy-ray polymerizable compound can be cured by irradiation with energy rays. Furthermore, the buffer layer-forming composition containing an energy-ray polymerizable compound more preferably contains urethane (meth)acrylate (a1). More preferably, the buffer layer-forming composition contains, in addition to (a1), a polymerizable compound (a2) having an alicyclic or heterocyclic group with 6 to 20 ring-forming atoms and / or a polymerizable compound (a3) ​​having a functional group. In addition, the buffer layer-forming composition may contain a polyfunctional polymerizable compound (a4) in addition to the components (a1) to (a3). Furthermore, the buffer layer-forming composition preferably contains a photopolymerization initiator, and may contain other additives and resin components to the extent that they do not impair the effects of the present invention. The following describes in detail each component contained in the buffer layer-forming composition containing energy ray polymerizable compounds.

[0076] (Urethane (meth)acrylate (a1)) Urethane (meth)acrylate (a1) is a compound having at least a (meth)acryloyl group and a urethane bond, and possessing the property of polymerization curing by energy ray irradiation. Urethane (meth)acrylate (a1) is an oligomer or polymer.

[0077] The weight-average molecular weight (Mw) of component (a1) is preferably 1,000 to 100,000, more preferably 2,000 to 60,000, and even more preferably 10,000 to 30,000. The number of (meth)acryloyl groups in component (a1) (hereinafter also referred to as "number of functional groups") may be monofunctional, difunctional, or trifunctional or more, but monofunctional or difunctional is preferred.

[0078] Component (a1) can be obtained, for example, by reacting a terminal isocyanate urethane prepolymer, which is obtained by reacting a polyol compound with a polyvalent isocyanate compound, with a (meth)acrylate having a hydroxyl group. Component (a1) may be used alone or in combination of two or more components.

[0079] The polyol compound used as a raw material for component (a1) is not particularly limited as long as it is a compound having two or more hydroxyl groups. Specific examples of polyol compounds include alkylenediols, polyether-type polyols, polyester-type polyols, and polycarbonate-type polyols. Among these, polyester-type polyols or polycarbonate-type polyols are preferred.

[0080] The polyol compound may be a bifunctional diol, a trifunctional triol, or a polyol with four or more functions, but a bifunctional diol is preferred, and a polyester-type diol or a polycarbonate-type diol is more preferred.

[0081] Examples of polyvalent isocyanate compounds include aliphatic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate; alicyclic diisocyanates such as isophorone diisocyanate, norbornane diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, and ω,ω'-diisocyanate dimethylcyclohexane; and aromatic diisocyanates such as 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, tolidine diisocyanate, tetramethylene xylylene diisocyanate, and naphthalene-1,5-diisocyanate. Among these, isophorone diisocyanate, hexamethylene diisocyanate, and xylylene diisocyanate are preferred.

[0082] A urethane (meth)acrylate (a1) can be obtained by reacting the above-mentioned polyol compound with a polyvalent isocyanate compound to obtain a terminal isocyanate urethane prepolymer, and then reacting the (meth)acrylate having a hydroxyl group with the (meth)acrylate having a hydroxyl group. The (meth)acrylate having a hydroxyl group is not particularly limited as long as it is a compound having at least one molecule containing both a hydroxyl group and a (meth)acryloyl group.

[0083] Specific examples of (meth)acrylates having a hydroxyl group include, for example, hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 4-hydroxycyclohexyl (meth)acrylate, 5-hydroxycyclooctyl (meth)acrylate, 2-hydroxy-3-phenyloxypropyl (meth)acrylate, pentaerythritol tri(meth)acrylate, polyethylene glycol mono(meth)acrylate, and polypropylene glycol mono(meth)acrylate; hydroxyl group-containing (meth)acrylamides such as N-methylol (meth)acrylamide; and reaction products obtained by reacting vinyl alcohol, vinyl phenol, and diglycidyl esters of bisphenol A with (meth)acrylic acid. Among these, hydroxyalkyl (meth)acrylate is preferred, and 2-hydroxyethyl (meth)acrylate is more preferred.

[0084] The conditions for reacting the terminal isocyanate urethane prepolymer and the (meth)acrylate having a hydroxyl group are preferably such that the reaction is carried out at 60-100°C for 1-4 hours in the presence of a solvent and catalyst, which may be added as needed.

[0085] The content of component (a1) in the buffer layer forming composition is preferably 10 to 70 parts by mass, more preferably 20 to 60 parts by mass, based on the total amount (100 parts by mass) of the buffer layer forming composition.

[0086] (a2) Polymerizable compounds having alicyclic or heterocyclic groups with 6 to 20 ring-forming atoms Component (a2) is a polymerizable compound having an alicyclic or heterocyclic group with 6 to 20 ring-forming atoms, and more preferably a compound having at least one (meth)acryloyl group, and more preferably a compound having one (meth)acryloyl group. By using component (a2), the film-forming properties of the resulting buffer layer-forming composition can be improved.

[0087] Although there is some overlap between the definition of component (a2) and the definition of component (a3) ​​described later, the overlapping portion is included in component (a3). For example, a compound having at least one (meth)acryloyl group, an alicyclic or heterocyclic group with 6 to 20 ring-forming atoms, and a functional group such as a hydroxyl group, epoxy group, amide group, or amino group is included in the definitions of both component (a2) and component (a3), but in this invention, such a compound is included in component (a3).

[0088] The number of ring-forming atoms in the alicyclic or heterocyclic group of component (a2) is preferably 6 to 20, more preferably 6 to 18, even more preferably 6 to 16, and particularly preferably 7 to 12. Examples of atoms that form the ring structure of the heterocyclic group include carbon atoms, nitrogen atoms, oxygen atoms, sulfur atoms, and the like.

[0089] The number of ring-forming atoms refers to the number of atoms that make up the ring itself in a compound with a ring-shaped structure. Atoms that do not form a ring (for example, hydrogen atoms bonded to ring-forming atoms) and atoms included in substituents when the ring is substituted by substituents are not included in the number of ring-forming atoms.

[0090] Specific components (a2) include, for example, alicyclic group-containing (meth)acrylates such as isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyloxy (meth)acrylate, cyclohexyl (meth)acrylate, and adamantane (meth)acrylate; heterocyclic group-containing (meth)acrylates such as tetrahydrofurfuryl (meth)acrylate, morpholine (meth)acrylate, and cyclic trimethylolpropane formal acrylate; and the like.

[0091] Furthermore, component (a2) may be used alone or in combination of two or more types. Among alicyclic group-containing (meth)acrylates, isobornyl (meth)acrylate is preferred.

[0092] The content of component (a2) in the buffer layer forming composition is preferably 10 to 80 parts by mass, more preferably 30 to 70 parts by mass, based on the total amount (100 parts by mass) of the buffer layer forming composition.

[0093] (Polymerizable compound having a functional group (a3)) Component (a3) ​​is a polymerizable compound containing functional groups such as hydroxyl groups, epoxy groups, amide groups, and amino groups, and is more preferably a compound having at least one (meth)acryloyl group, and more preferably a compound having one (meth)acryloyl group.

[0094] Component (a3) ​​has good compatibility with component (a1), making it easier to adjust the viscosity of the buffer layer-forming composition to an appropriate range. Furthermore, good buffering performance is achieved even with a relatively thin buffer layer.

[0095] Examples of component (a3) ​​include hydroxyl group-containing (meth)acrylates, epoxy group-containing compounds, amide group-containing compounds, and amino group-containing (meth)acrylates.

[0096] Examples of hydroxyl group-containing (meth)acrylates include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, phenylhydroxypropyl (meth)acrylate, and 2-hydroxy-3-phenoxypropyl acrylate.

[0097] Examples of epoxy group-containing compounds include glycidyl (meth)acrylate, methylglycidyl (meth)acrylate, and allyl glycidyl ether. Among these, epoxy group-containing (meth)acrylates such as glycidyl (meth)acrylate and methylglycidyl (meth)acrylate are preferred.

[0098] Examples of amide group-containing compounds include (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-butyl(meth)acrylamide, N-methylol(meth)acrylamide, N-methylolpropane(meth)acrylamide, N-methoxymethyl(meth)acrylamide, and N-butoxymethyl(meth)acrylamide.

[0099] Examples of amino group-containing (meth)acrylates include primary amino group-containing (meth)acrylates, secondary amino group-containing (meth)acrylates, and tertiary amino group-containing (meth)acrylates.

[0100] Among these, hydroxyl group-containing (meth)acrylates are preferred, and hydroxyl group-containing (meth)acrylates having an aromatic ring, such as phenylhydroxypropyl (meth)acrylate, are more preferred. Furthermore, component (a3) ​​may be used alone or in combination of two or more types.

[0101] The content of component (a3) ​​in the buffer layer forming composition is preferably 0 to 40 parts by mass, more preferably 0 to 35 parts by mass, and even more preferably 0 to 30 parts by mass, based on the total amount (100 parts by mass) of the buffer layer forming composition.

[0102] (Polyfunctional polymerizable compound (a4)) A polyfunctional polymerizable compound is a compound having two or more photopolymerizable unsaturated groups. Photopolymerizable unsaturated groups are functional groups containing a carbon-carbon double bond, such as (meth)acryloyl groups, vinyl groups, allyl groups, and vinylbenzyl groups. Two or more types of photopolymerizable unsaturated groups may be combined. A three-dimensional network structure (crosslinked structure) is formed when a photopolymerizable unsaturated group in the polyfunctional polymerizable compound reacts with the (meth)acryloyl group in component (a1), or when photopolymerizable unsaturated groups in component (a4) react with each other. When using a polyfunctional polymerizable compound, the number of crosslinked structures formed by energy ray irradiation tends to increase compared to when using a compound containing only one photopolymerizable unsaturated group.

[0103] Note that there is some overlap between the definition of component (a4) and the definitions of components (a2) and (a3) ​​mentioned above, but the overlapping parts are included in component (a4). For example, a compound having an alicyclic or heterocyclic group with 6 to 20 ring-forming atoms and having two or more (meth)acryloyl groups is included in the definitions of both component (a4) and component (a2), but in this invention, such a compound is included in component (a4). Also, a compound containing a functional group such as a hydroxyl group, epoxy group, amide group, or amino group and having two or more (meth)acryloyl groups is included in the definitions of both component (a4) and component (a3), but in this invention, such a compound is included in component (a4).

[0104] From the above viewpoint, the number of photopolymerizable unsaturated groups (number of functional groups) in a polyfunctional polymerizable compound is preferably 2 to 10, and more preferably 3 to 6.

[0105] Furthermore, the weight-average molecular weight of component (a4) is preferably 30 to 40,000, more preferably 100 to 10,000, and even more preferably 200 to 1,000.

[0106] Specific components (a4) include, for example, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate with 200 to 800 glycol-derived repeating units, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, divinylbenzene, vinyl (meth)acrylate, divinyl adipate, N,N'-methylenebis(meth)acrylamide, etc. Polyethylene glycol di(meth)acrylate is generally expressed with the number of glycol units in parentheses; for example, if the number of glycol units is 600, it is written as polyethylene glycol (600) diacrylate.

[0107] Furthermore, component (a4) may be used alone or in combination of two or more types. Among these, polyethylene glycol diacrylate and neopentyl glycol di(meth)acrylate are preferred.

[0108] The content of component (a4) in the buffer layer forming composition is preferably 2 to 40 parts by mass, more preferably 3 to 20 parts by mass, and even more preferably 5 to 15 parts by mass, based on the total amount (100 parts by mass) of the buffer layer forming composition.

[0109] (Polymerizable compounds other than components (a1) to (a4) (a5)) The buffer layer forming composition may also contain other polymerizable compounds (a5) other than the above components (a1) to (a4), as long as the effects of the present invention are not impaired.

[0110] Examples of component (a5) include alkyl (meth)acrylates having an alkyl group with 1 to 20 carbon atoms; vinyl compounds such as styrene, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, N-vinylformamide, N-vinylpyrrolidone, and N-vinylcaprolactam. Component (a5) may be used alone or in combination of two or more.

[0111] The content of component (a5) in the buffer layer forming composition is preferably 0 to 20 parts by mass, more preferably 0 to 10 parts by mass, even more preferably 0 to 5 parts by mass, and particularly preferably 0 to 2 parts by mass, based on the total amount (100 parts by mass) of the buffer layer forming composition.

[0112] (Photopolymerization initiator) The buffer layer forming composition preferably contains a photopolymerization initiator, from the viewpoint of shortening the polymerization time by light irradiation and reducing the amount of light irradiation when forming the buffer layer.

[0113] Examples of photopolymerization initiators include benzoin compounds, acetophenone compounds, acyl phosphinoxide compounds, titanocene compounds, thioxanthone compounds, peroxide compounds, and photosensitizers such as amines and quinones. More specifically, examples include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl phenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyrolnitrile, dibenzyl, diacetyl, 8-chloranthraquinone, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

[0114] These photopolymerization initiators can be used individually or in combination of two or more.

[0115] The amount of photopolymerization initiator in the buffer layer-forming composition is preferably 0.05 to 15 parts by mass, more preferably 0.1 to 10 parts by mass, and even more preferably 0.3 to 5 parts by mass, based on 100 parts by mass of the total amount of energy ray polymerizable compounds.

[0116] (Other additives) The buffer layer forming composition may contain other additives as long as they do not impair the effects of the present invention. Examples of other additives include antistatic agents, antioxidants, plasticizers, fillers, rust inhibitors, pigments, dyes, and the like. When these additives are included, the amount of each additive in the buffer layer forming composition is preferably 0.01 to 6 parts by mass, more preferably 0.1 to 3 parts by mass, based on 100 parts by mass of the total amount of energy ray polymerizable compounds.

[0117] (Resin components) The buffer layer-forming composition may contain a resin component, to the extent that it does not impair the effects of the present invention. Examples of resin components include polyene-thiol resins, polyolefin resins such as polybutene, polybutadiene, and polymethylpentene, and thermoplastic resins such as styrene copolymers.

[0118] The content of these resin components in the buffer layer forming composition is preferably 0 to 20 parts by mass, more preferably 0 to 10 parts by mass, even more preferably 0 to 5 parts by mass, and particularly preferably 0 to 2 parts by mass, based on the total amount (100 parts by mass) of the buffer layer forming composition.

[0119] The buffer layer formed from a buffer layer-forming composition containing an energy-ray polymerizable compound is obtained by polymerizing and curing the buffer layer-forming composition of the above composition by energy-ray irradiation. In other words, the buffer layer is a cured product of the buffer layer-forming composition.

[0120] Therefore, the buffer layer contains polymerization units derived from component (a1). Preferably, the buffer layer also contains polymerization units derived from component (a2) and / or component (a3). Furthermore, it may also contain polymerization units derived from component (a4) and / or component (a5). The content ratio of each polymerization unit in the buffer layer usually corresponds to the ratio (compounding ratio) of each component constituting the buffer layer forming composition. For example, if the content of component (a1) in the buffer layer forming composition is 10 to 70 parts by mass per 100 parts by mass of the total amount of the buffer layer forming composition, the buffer layer contains 10 to 70 parts by mass of polymerization units derived from component (a1). Similarly, if the content of component (a2) in the buffer layer forming composition is 10 to 80 parts by mass per 100 parts by mass of the total amount of the buffer layer forming composition, the buffer layer contains 10 to 80 parts by mass of polymerization units derived from component (a2). The same applies to components (a3) ​​to (a5).

[0121] (Control of the rigidity and flexibility of the laminate between the substrate and the buffer layer) As described above, the semiconductor processing adhesive tape 10 of the present invention has a rigidity / softness of 68 mm or more in the laminate of the base material 11 and the buffer layer 13. Because the rigidity / softness of the laminate is within this range, even when the semiconductor processing adhesive tape 10 holding the chip group is supported by a Bernoulli chuck 20, the adhesive tape 10 is less likely to deform and sagging can be prevented. As a result, contact between chips is also reduced, and chipping can be suppressed.

[0122] The rigidity and flexibility of the laminate can be controlled by the material and thickness of the base material 11 and the buffer layer 13. Using a highly rigid or thick film as the base material increases the rigidity and flexibility. Similarly, using a film with a dense cross-linking structure or a thick film as the buffer layer also increases the rigidity and flexibility.

[0123] The buffer layer is obtained by curing the buffer layer-forming composition described above. The crosslinking structure of the buffer layer can be adjusted by selecting the composition of the buffer layer-forming composition. Therefore, in order to control the rigidity and softness of the laminate of the substrate and the buffer layer within the aforementioned range, the types and amounts of the above-mentioned components constituting the buffer layer-forming composition may be adjusted. Guidelines for adjusting the types and amounts of each component are described below. For example, if the number of (meth)acroyl groups in urethane (meth)acrylate (a1) is large, the number of cross-linked structures in the buffer layer increases, and the rigidity of the laminate between the substrate and the buffer layer increases. The rigidity and flexibility of the laminate between the substrate and the buffer layer can be adjusted by the type and amount of urethane (meth)acrylate (a1), polymerizable compounds having alicyclic or heterocyclic groups with 6 to 20 ring-forming atoms (a2), polymerizable compounds having functional groups (a3), and polyfunctional polymerizable compounds (a4).

[0124] When the buffer layer contains a large amount of cross-linked structures, the buffer layer becomes harder, and the rigidity of the laminate between the substrate and the buffer layer tends to increase. Therefore, by adjusting the amount of components involved in the formation of cross-linked structures, the rigidity of the laminate can be controlled within an appropriate range. Examples of components involved in the formation of cross-linked structures include the (meth)acroyl group of urethane (meth)acrylate (a1) and polyfunctional polymerizable compounds (a4). In particular, polyfunctional polymerizable compounds (a4) are easy to use and are useful components for the formation of cross-linked structures.

[0125] Furthermore, if the buffer layer contains relatively soft constituent units (for example, units with long chain lengths), the rigidity of the laminate between the substrate and the buffer layer tends to decrease. Therefore, by adjusting the amount of components involved in the formation of long-chain structures, the rigidity of the laminate can be controlled within an appropriate range. Examples of units with long chain lengths include urethane chains in urethane (meth)acrylate (a1).

[0126] However, if the rigidity / softness increases excessively, when peeling the semiconductor processing adhesive tape 10 from the chip group 24, the repulsive force due to the bending of the tape becomes large, applying excessive pressure to the chips and potentially damaging them. In other words, if the rigidity / softness is too high, it may become difficult to peel off the adhesive tape 10, so it is preferable that the rigidity / softness be 150 mm or less.

[0127] The buffer layer described above may contain additives such as plasticizers, lubricants, infrared absorbers, ultraviolet absorbers, fillers, colorants, antistatic agents, antioxidants, and catalysts, to the extent that they do not impair the effects of the present invention. Furthermore, the buffer layer described above may be transparent or opaque, and may be colored or vapor-deposited as desired.

[0128] [Release sheet] A release liner may be attached to the surface of the adhesive tape. Specifically, the release liner is attached to the surface of the adhesive layer of the adhesive tape. The release liner protects the adhesive layer during transport and storage. The release liner is attached to the adhesive tape in a removable manner and is peeled off and removed from the adhesive tape before the adhesive tape is used (i.e., before wafer attachment). The release sheet used is one in which at least one side has been treated to release the material. Specifically, this includes a release sheet in which a release agent is applied to the surface of a release sheet substrate.

[0129] A resin film is preferred as the substrate for the release sheet, and examples of resins constituting the resin film include polyester resin films such as polyethylene terephthalate resin, polybutylene terephthalate resin, and polyethylene naphthalate resin, and polyolefin resins such as polypropylene resin and polyethylene resin. Examples of release agents include rubber elastomers such as silicone resins, olefin resins, isoprene resins, and butadiene resins, long-chain alkyl resins, alkyd resins, and fluorine resins. The thickness of the release sheet is not particularly limited, but is preferably 10 to 200 μm, and more preferably 20 to 150 μm.

[0130] [Method of manufacturing adhesive tape] There are no particular limitations on the method for manufacturing the adhesive tape of the present invention, and it can be manufactured by known methods. For example, the method for manufacturing an adhesive tape having a base material, an adhesive layer provided on one side of the base material, and a buffer layer provided on the other side of the base material is as follows.

[0131] When the buffer layer is formed from a buffer layer forming composition containing an energy ray polymerizable compound, the buffer layer is formed by coating and curing the buffer layer forming composition onto a release sheet, bonding the buffer layer to the substrate, and then removing the release sheet to obtain a laminate of the buffer layer and the substrate.

[0132] Then, an adhesive layer provided on a release sheet is bonded to the substrate side of the laminate, and an adhesive tape can be manufactured in which a release sheet is attached to the surface of the adhesive layer. The release sheet attached to the surface of the adhesive layer can be peeled off and removed as appropriate before use of the adhesive tape.

[0133] One method for forming an adhesive layer on a release sheet is to directly apply an adhesive (adhesive composition) to the release sheet using a known application method, and then heat-dry the applied film to form the adhesive layer.

[0134] Alternatively, an adhesive layer may be formed by directly applying an adhesive (adhesive composition) to one side of the substrate. Examples of adhesive application methods include the spray coating method, bar coating method, knife coating method, roll coating method, blade coating method, die coating method, gravure coating method, etc., as described in the method for manufacturing the buffer layer.

[0135] One method for forming a buffer layer on a release sheet is to directly apply a buffer layer-forming composition to the release sheet using a known coating method to form a coating film, and then irradiate this coating film with energy rays to form the buffer layer. Alternatively, the buffer layer may be formed by directly applying the buffer layer-forming composition to one side of a substrate and then heating and drying it or irradiating the coating film with energy rays.

[0136] Examples of methods for applying the buffer layer-forming composition include spin coating, spray coating, bar coating, knife coating, roll coating, blade coating, die coating, and gravure coating. Furthermore, to improve applicability, an organic solvent may be added to the buffer layer-forming composition, and the solution may be applied onto a release sheet.

[0137] When the buffer layer forming composition contains an energy ray polymerizable compound, it is preferable to form a buffer layer by curing the coated film of the buffer layer forming composition by irradiating it with energy rays. The curing of the buffer layer may be performed in a single curing treatment or in multiple stages. For example, the coated film on the release sheet may be completely cured to form a buffer layer before being bonded to the substrate, or the buffer layer forming film may be formed in a semi-cured state without completely curing the coated film, and after bonding the buffer layer forming film to the substrate, it may be irradiated with energy rays again to completely cure it and form a buffer layer. Ultraviolet light is preferred as the energy ray used in the curing treatment. When curing, the coated film of the buffer layer forming composition may be exposed, but it is preferable to cure it by irradiating it with energy rays while the coated film is covered with a release sheet or substrate and the coated film is not exposed.

[0138] Furthermore, a method for manufacturing an adhesive tape having buffer layers on both sides of the base material can be obtained, for example, by the method described above, by obtaining a laminate in which the buffer layer and the base material and the buffer layer are stacked in that order, and then forming an adhesive layer on one side of the buffer layer.

[0139] [Manufacturing method for semiconductor devices] The adhesive tape according to the present invention is preferably used when the tape is attached to the surface of a semiconductor wafer to perform backside grinding of the wafer. More preferably, the adhesive tape according to the present invention is preferably used in DBG, in which backside grinding and wafer fragmentation are performed simultaneously. Particularly preferably, the adhesive tape according to the present invention is preferably used in LDBG, in which a group of chips with a small kerf width is obtained when the semiconductor wafer is fragmented. The term "group of chips" refers to a plurality of semiconductor chips that are held on the adhesive tape according to the present invention and are aligned in the shape of a wafer. As a non-limited example of the use of adhesive tape, a method for manufacturing a semiconductor device will be described in more detail below.

[0140] The method for manufacturing a semiconductor device specifically comprises at least the following steps 1 to 5. Step 1: The above adhesive tape is attached to the surface of the semiconductor wafer, and the adhesive tape is cut along the outer edge of the semiconductor wafer. Step 2: A step of forming grooves from the surface side of a semiconductor wafer, or forming a modified region inside a semiconductor wafer from the surface or back surface of a semiconductor wafer. Step 3: A semiconductor wafer on which adhesive tape has been applied to the surface and on which the groove or modified region has been formed is ground from the back side to separate it into multiple chips, starting from the groove or modified region. Step 4: A step of supporting and transporting the semiconductor processing adhesive tape, on which the multiple individualized chips are held, using a Bernoulli chuck. Step 5: The process of peeling the adhesive tape off the individual semiconductor wafers (i.e., multiple semiconductor chips).

[0141] The following describes in detail each step of the manufacturing method for the semiconductor device described above. (Process 1) In step 1, the adhesive tape of the present invention is attached to the surface of a semiconductor wafer via an adhesive layer and cut along the outer circumference of the semiconductor wafer. The adhesive tape is attached so as to cover the semiconductor wafer and the outer circumference table that extends around its periphery. The adhesive tape is then cut along the outer circumference of the semiconductor wafer using a cutter or the like. The cutting speed is usually 10 to 300 mm / s. The temperature of the cutter blade during cutting may be room temperature, or the cutter blade may be heated before cutting.

[0142] This step may be performed before or after step 2, which will be described later. For example, when forming a modified region on a semiconductor wafer, it is preferable to perform step 1 before step 2. On the other hand, when forming grooves on the surface of a semiconductor wafer by dicing or the like, step 1 is performed after step 2. That is, adhesive tape is applied in step 1 to the surface of the wafer having grooves formed in step 2, which will be described later.

[0143] The semiconductor wafer used in this manufacturing method may be a silicon wafer, or a wafer made of gallium arsenide, silicon carbide, lithium tantalate, lithium niobate, gallium nitride, indium phosphide, or glass wafer. The thickness of the semiconductor wafer before grinding is not particularly limited, but is usually around 500 to 1000 μm. In addition, the semiconductor wafer usually has circuits formed on its surface. Circuit formation on the wafer surface can be carried out by various methods, including conventionally used methods such as etching and lift-off methods.

[0144] (Process 2) In step 2, grooves are formed from the surface side of the semiconductor wafer, or modified regions are formed inside the semiconductor wafer from the surface or back surface. The grooves formed in this process are shallower than the thickness of the semiconductor wafer. The grooves can be formed by dicing using conventionally known wafer dicing equipment. Furthermore, in step 3, described later, the semiconductor wafer is separated into multiple semiconductor chips along the grooves.

[0145] Furthermore, the modified region is a brittle part of the semiconductor wafer, and it is the starting point for the semiconductor wafer to break down into individual semiconductor chips due to the thinning of the semiconductor wafer by grinding during the grinding process or the force applied by grinding. In other words, in step 2, the groove and the modified region are formed along the dividing line when the semiconductor wafer is divided into individual semiconductor chips in step 3, which will be described later.

[0146] The modified region is formed by irradiating the semiconductor wafer with a laser focused on the interior of the wafer. The laser irradiation may be performed from either the front or back side of the semiconductor wafer. In the embodiment where the modified region is formed, if step 2 is performed after step 1 and the laser irradiation is performed from the wafer surface, the laser will be irradiated onto the semiconductor wafer via adhesive tape.

[0147] A semiconductor wafer, to which adhesive tape has been applied and to which grooves or modified regions have been formed, is placed on a grinding table and held by suction to the grinding table. In this process, the semiconductor wafer is positioned with its surface facing the table when it is suctioned.

[0148] (Step 3) After steps 1 and 2, the back surface of the semiconductor wafer on the grinding table is ground to separate the semiconductor wafer into multiple semiconductor chips. In this process, back grinding is performed to thin the semiconductor wafer at least up to the bottom of the groove, if grooves are to be formed on the semiconductor wafer. This back grinding creates cuts that penetrate the wafer, and the semiconductor wafer is divided by these cuts into individual semiconductor chips.

[0149] On the other hand, if a modified region is formed, the grinding surface (back surface of the wafer) may reach the modified region through grinding, but it does not need to reach the modified region precisely. In other words, grinding should be done up to a position close to the modified region so that the semiconductor wafer is broken down into individual semiconductor chips, starting from the modified region. For example, the actual fragmentation of semiconductor chips may be performed by attaching a pickup tape, as described later, and then stretching the pickup tape.

[0150] The shape of the individual semiconductor chips may be rectangular or elongated, such as a rectangle. The thickness of the individual semiconductor chips is not particularly limited, but is preferably around 5 to 100 μm, and more preferably 10 to 45 μm. With LDBG, which involves creating a modified region inside the wafer with a laser and fragmenting the wafer using stress during back-side grinding, it becomes easy to achieve a thickness of 50 μm or less, more preferably 10 to 45 μm. The size of the individual semiconductor chips is not particularly limited, but a chip size of 600 mm is preferred. 2 Less than, more preferably 400 mm 2 Less than 300 mm, more preferably 300 mm 2It is less than [value missing]. After the back grinding is complete, dry polishing of the back surface of the chip may be performed. Dry polishing is a process of mirror-finishing the back surface of the fragmented chip using a dry grinding wheel. This process reduces the fracture layer on the back surface of the chip and increases its flexural strength.

[0151] (Step 4) After the backside grinding is complete, the adhesive tape holding the chip group is supported by a Bernoulli chuck and transported to the next process. At this time, as shown in Figure 2, the Bernoulli chuck is used to suction the surface on the upper side of the adhesive tape 10 where the chip group 24 is held, and the tape 10 is removed from the grinding table together with the chip group 24.

[0152] According to the semiconductor processing adhesive tape 10 of the present invention, because the rigidity and softness of the laminate of the base material 11 and the buffer layer 13 are within the above range, even when the semiconductor processing adhesive tape 10 holding the chip group 24 is supported by a Bernoulli chuck 20, the adhesive tape 10 is less likely to deform and sagging can be prevented. As a result, contact between chips is also reduced, and chipping can be suppressed.

[0153] (Step 5) Next, the semiconductor processing adhesive tape is peeled off the individual semiconductor wafers (i.e., multiple semiconductor chips). This step is carried out, for example, by the following method.

[0154] First, if the adhesive layer of the adhesive tape is formed from an energy-ray curable adhesive, the adhesive layer is cured by irradiating it with energy rays. Next, the pickup tape is attached to the back side of the individualized semiconductor wafer, and its position and orientation are aligned so that it can be picked up. At this time, the ring frame placed on the outer circumference of the wafer is also attached to the pickup tape, and the outer edge of the pickup tape is fixed to the ring frame. The wafer and ring frame may be attached to the pickup tape at the same time, or at different times. Next, the adhesive tape is peeled off from the multiple semiconductor chips held on the pickup tape. Note that if the rigidity of the adhesive tape 10 is too high, the repulsive force due to bending when peeling off the adhesive tape will be large, and excessive pressure may be applied to the chips, potentially damaging them. For this reason, it is preferable to control the rigidity within an appropriate range.

[0155] Subsequently, multiple semiconductor chips are picked up from the pickup tape and fixed onto a substrate or other surface to manufacture a semiconductor device. The pickup tape is not particularly limited, but for example, it is composed of an adhesive tape comprising a base material and an adhesive layer provided on at least one surface of the base material.

[0156] Alternatively, adhesive tape can be used instead of pickup tape. Examples of adhesive tape include a laminate of a film-like adhesive and a release sheet, a laminate of a dicing tape and a film-like adhesive, and a dicing-die bonding tape consisting of an adhesive layer and a release sheet that have the functions of both a dicing tape and a die bonding tape. In other words, this embodiment may include a step of attaching the dicing-die bonding tape to the back surface of the semiconductor wafer. Alternatively, a film-like adhesive may be attached to the back surface of the individualized semiconductor wafer before attaching the pickup tape. When using a film-like adhesive, the film-like adhesive may have the same shape as the wafer.

[0157] When using adhesive tape or when a film-like adhesive is bonded to the back side of a semiconductor wafer that has been separated before applying the pickup tape, multiple semiconductor chips on the adhesive tape or pickup tape are picked up together with the adhesive layer, which is divided to match the shape of the semiconductor chips. The semiconductor chips are then fixed onto a substrate or the like via the adhesive layer, and a semiconductor device is manufactured. The division of the adhesive layer is performed by laser or expansion. Alternatively, a protective film-forming tape may be used to form a protective film on the back side of the chip instead of adhesive tape.

[0158] The above describes an example of using the adhesive tape according to the present invention in a method of framing semiconductor wafers by DBG or LDBG. The adhesive tape according to the present invention is preferably used in LDBG, which yields a smaller kerf width and thinner chip group when semiconductor wafers are framing. The adhesive tape according to the present invention can also be used in normal back grinding, and can also be used to temporarily hold workpieces during processing of glass, ceramics, etc. It can also be used as various types of re-peelable adhesive tapes. [Examples]

[0159] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

[0160] The measurement and evaluation methods are as follows. The results are shown in Table 1.

[0161] [Measurement of stiffness and flexibility] The laminate of the base material and buffer layer was cut to a width of 20 mm x length of 150 mm, and its stiffness was measured at 23°C and 50% RH using a cantilever-type stiffness tester (manufactured by TOYOSEIKI Corporation) (in accordance with JIS L1086). Since static electricity can affect the measured stiffness, static electricity was removed before measurement. Also, when the laminate is in roll form, the value in the MD (machine direction) direction is large, so the value in the CD (cross direction) direction was evaluated. When obtaining a laminate of the base material and buffer layer from an adhesive tape which is a laminate of a buffer layer / base material / adhesive layer, the stiffness is measured after removing the adhesive layer with a solvent or the like.

[0162] [Transportability evaluation] A silicon wafer with a diameter of 12 inches and a thickness of 775 μm was coated with the semiconductor processing adhesive tape manufactured in the examples and comparative examples using a backgrind tape laminator (Lintec Corporation, model name "RAD3510F / 12"). A laser saw (Disco Corporation, model name "DFL7361") was used to form a grid-like modified region on the wafer. The grid size was 10 mm x 10 mm.

[0163] Next, using a back grinding machine (Disco Corporation, machine name "DGP8761"), the wafer was ground (including dry polishing) until it reached a thickness of 30 μm, and the wafer was separated into multiple chips. The separated chips were observed with a digital microscope, and the number of chips with cracks was counted and classified according to the following criteria based on the size of the cracks. The crack size (μm) was determined by comparing the length of the crack along the longitudinal direction of the chip (μm) with the length of the crack along the transverse direction of the chip (μm), and the larger value was used.

[0164] (standard) Large cracks: Cracks with a size exceeding 20 μm Medium cracks: Cracks with a size of 10 μm or more and 20 μm or less. Small cracks: Cracks with a size of less than 10 μm

[0165] After measuring the number of cracks, a Bernoulli chuck (a circular section with an outer diameter of 300 mm and an inner diameter of 100 mm, on which 18 pads are provided at approximately equal intervals, with a distance of 25 mm from the outer circumference of the circular section to the center of each pad) was used to non-contact suction from the surface of the chip group / adhesive tape that was holding the chip group. The chip group / adhesive tape was then removed from the grinding table of the grinding machine, the number of cracks was measured again, and the increase in the number of cracks was measured.

[0166] A product was rated as good (A) if all of the following conditions were met, and as poor (F) if even one condition was not met. The number of large cracks is less than 1 per wafer (624 chips). The increase in the number of medium cracks is less than 10 per wafer (624 chips). The increase in small cracks is less than 30 per wafer (624 chips).

[0167] All mass values ​​in the following examples and comparative examples are calculated on a solid content basis. <Example 1> (1) Base material As the substrate, a PET film with a double-sided coating layer (manufactured by Toyobo, product name [Cosmoshine A4300], thickness: 50 μm, Young's modulus at 23°C: 2550 MPa) was prepared.

[0168] (2) Adhesive layer (Preparation of adhesive composition) Acrylic copolymer (BA / MMA / 2HEA) having structural units derived from N-butyl acrylate (BA), methyl methacrylate (MMA), and 2-hydroxyethyl acrylate (2HEA). HEAA solution of adhesive with a solid content of 32% by mass was prepared by mixing 100 parts by mass of (52 / 20 / 28 (mass%), weight-average molecular weight approximately 500,000), 6 parts by mass of a polyfunctional urethane acrylate-based UV-curable resin, 1 part by mass of a diisocyanate-based curing agent, and 1 part by mass of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide as a photopolymerization initiator, and diluting with methyl ethyl ketone. Then, the solution of the above adhesive composition was applied to the release-treated surface of a release sheet (Lintec Corporation, product name "SP-PET381031", a polyethylene terephthalate (PET) film with silicone release treatment, thickness: 38 μm), and drying to produce a release sheet with an adhesive layer having a thickness of 20 μm.

[0169] (3)Buffer layer (Preparation of buffer layer-forming composition) As energy ray polymerizable compounds, a urethane acrylate oligomer (CN8888), isobornyl acrylate (IBXA), cyclic trimethylolpropane formal acrylate, neopentyl glycol diacrylate, and polyethylene glycol (600) diacrylate purchased from Sartomer were blended in the amounts listed in Table 1. Furthermore, 2.0 parts by mass of 2-hydroxy-2-methyl-1-phenyl-propan-1-one (BASF, product name "Omnirad 1173") was added as a photopolymerization initiator to prepare a buffer layer forming composition.

[0170] The above-mentioned buffer layer-forming composition was applied to the peeled surface of a release sheet (Lintec Corporation, product name "SP-PET381031", a polyethylene terephthalate (PET) film with silicone release treatment, thickness: 38 μm) to form a coating film. Then, ultraviolet light was irradiated onto the coating film to partially cure it, forming a semi-cured buffer layer with a thickness of 28 μm.

[0171] The above ultraviolet irradiation was performed using a belt conveyor type ultraviolet irradiation device (product name "ECS-401GX", manufactured by iGraphics Co., Ltd.) and a high-pressure mercury lamp (product name "H04-L41", manufactured by iGraphics Co., Ltd.), with a lamp height of 260 mm, output of 80 W / cm, and illuminance of 70 mW / cm. 2 , irradiation amount 30mW / cm 2 The procedure was carried out under the specified irradiation conditions. The surface of the formed semi-cured film was then bonded to the first coating layer of the substrate, and ultraviolet light was irradiated again from the release sheet side on the semi-cured film to completely cure it, forming a buffer layer with a thickness of 28 μm. The rigidity and flexibility of the resulting "laminated material of substrate and buffer layer" were measured. The results are shown in Table 1.

[0172] (4) Preparation of adhesive tape Next, the adhesive layer of the release sheet with adhesive layer was bonded onto the second coating layer of the PET film with double-sided coating layers to produce an adhesive tape for semiconductor processing. The transportability of the adhesive tape for semiconductor processing was evaluated. The results are shown in Table 1.

[0173] <Examples 2-4, Comparative Examples 1 and 2> Except for changing the composition of the buffer layer-forming composition as shown in Table 1, a semiconductor processing adhesive tape was prepared in the same manner as in Example 1. The results are shown in Table 1.

[0174] [Table 1]

[0175] Based on the above results, the adhesive tape for semiconductor processing according to the present invention controls the rigidity and flexibility of the tape within an appropriate range. Therefore, even when the adhesive tape for semiconductor processing, on which the chip group is held, is transported using a Bernoulli chuck, there is no bending of the tape, and chipping can be suppressed. [Explanation of symbols]

[0176] 10 Adhesive Tapes 11 Base material 12 Adhesive layer 13 Buffer layer 20 Bernoullichak 21 pads 22 Arc section 23 Arms 24 chip group

Claims

1. An adhesive tape comprising a base material, a buffer layer provided on one side of the base material, and an adhesive layer provided on the other side of the base material, The rigidity of the laminate between the base material and the buffer layer is 68 mm or more. A semiconductor processing adhesive tape wherein the buffer layer is a cured product of a buffer layer forming composition containing an energy ray polymerizable compound.

2. The adhesive tape for semiconductor processing according to claim 1, wherein the Young's modulus of the substrate at 23°C is 1000 MPa or more.

3. The semiconductor processing adhesive tape according to claim 1 or 2, wherein the thickness of the substrate is 80 μm or less.

4. A semiconductor processing adhesive tape according to any one of claims 1 to 3, used by being attached to the surface of a semiconductor wafer in a process of grinding the back surface of a semiconductor wafer in which grooves are formed on the surface of the semiconductor wafer or modified regions are formed on the semiconductor wafer, thereby separating the semiconductor wafer into semiconductor chips by grinding.

5. A step of attaching a semiconductor processing adhesive tape according to any one of claims 1 to 3 to the surface of a semiconductor wafer, and cutting the adhesive tape along the outer circumference of the semiconductor wafer, A step of forming a groove from the surface side of the semiconductor wafer, or forming a modified region inside the semiconductor wafer from the surface or back surface of the semiconductor wafer, A step of grinding a semiconductor wafer on which the adhesive tape is attached to the surface and on which the groove or modified region is formed, from the back side to separate it into multiple chips starting from the groove or modified region, A step of supporting and transporting the semiconductor processing adhesive tape, on which the individualized chips are held, using a Bernoulli chuck, The process of peeling the adhesive tape from the plurality of chips, A method for manufacturing a semiconductor device comprising the same equipment.

6. Furthermore, the method for manufacturing a semiconductor device according to claim 5, further comprising the step of attaching a dicing die bonding tape to the back surface of a semiconductor chip.

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