TW202237772A - Semiconductor processing adhesive tape, and method for manufacturing semiconductor device - Google Patents

Abstract

To provide a semiconductor processing adhesive tape capable of suppressing the cracking of chips when peeling off the adhesive tape. A semiconductor processing adhesive tape having a base material and an adhesive layer, wherein, in a state in which one face of the adhesive layer is exposed to the atmosphere, after the adhesive tape is irradiated with ultraviolet light under the conditions of an illuminance of 220mW/cm2 and a light quantity of 500 mJ/cm3, the surface modulus of elasticity of the exposed face of the adhesive layer is 5 MPa or more.

Description

Adhesive tape for semiconductor processing and method for manufacturing semiconductor device

The present invention relates to an adhesive tape for semiconductor processing, and more specifically relates to an adhesive tape and a method for manufacturing a semiconductor device using the adhesive tape. The method is used to provide grooves on the front surface of a wafer or to provide a modified region inside the wafer by laser. When manufacturing a semiconductor device by individualizing wafers due to stress during wafer back grinding, etc., it is preferable to use this adhesive tape for temporarily stabilizing the semiconductor wafer or chip.

In the progress of miniaturization and multifunctionalization of various electronic devices, semiconductor chips mounted thereon are also required to be miniaturized and thinned. In order to reduce the thickness of the wafer, the back surface of the semiconductor wafer is generally ground to adjust the thickness. In addition, in order to obtain thinner wafers, it is also possible to use a method called dicing before grinding (DBG: Dicing Before Grinding; cutting first and then grinding) to form grooves of a predetermined depth from the front side of the wafer with a dicing blade. , Grinding is performed from the back side of the wafer, and the wafer is individually sliced by grinding. At DBG, wafer backside grinding and wafer individualization can be performed at the same time, so thin wafers can be manufactured efficiently.

In addition, in recent years, as a modified example of the dicing-first method, a method has been proposed in which a modified region is provided inside the wafer by laser, and the wafer is divided into individual pieces by stress during wafer back grinding. Hereinafter, this method may be described as LDBG (Laser Dicing Before Grinding; laser dicing before grinding). In LDBG, since the wafer is cut in the crystallographic direction starting from the modified region, the occurrence of chipping can be reduced compared to the first dicing method using a dicing blade. As a result, a wafer having excellent flexural strength can be obtained, and it can contribute to further thinning of the wafer. Also, compared to DBG, which uses a dicing blade to form a groove of a predetermined depth on the surface of the wafer, there is no area for the wafer to be cut off by the dicing blade, that is, because the kerf width is extremely small, the wafer The yield is excellent.

In order to protect the circuit on the front of the wafer and to stabilize the semiconductor wafer and the semiconductor chip when grinding the back of the semiconductor wafer or manufacturing the chip by DBG, LDBG, etc., it is generally attached on the front of the wafer. Adhesive tape for back grinding sheet. After backside grinding, an adhesive tape having an adhesive layer is attached to the ground surface. Thereafter, the adhesive tape affixed to the surface of the wafer is peeled off after the adhesive force is reduced by irradiation of energy rays such as ultraviolet rays. Through such steps, an adhesive tape is attached to the backside of the wafer.

Here, Patent Document 1 proposes an adhesive tape having an adhesive layer using an adhesive whose tack reduction rate after irradiation with oxygen-containing ultraviolet rays is 60% or more. However, once the tape described in Patent Document 1 is used, when the finished thickness of the wafer is reduced to about 30 μm, when the adhesive tape is peeled off, wafer chipping or breakage (hereinafter referred to as "wafer cracking") may occur. ) and so on. [Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. 2015-185691

[Problem to be solved by the invention]

As a result of careful research by the inventors of the present case to solve the above-mentioned problems, it was found that a region where the adhesive force was not sufficiently reduced even when the adhesive sheet was irradiated with energy rays such as ultraviolet rays due to the thinning of the semiconductor wafer after grinding was found. When the adhesive tape was peeled off, cracks occurred on the wafer.

FIG. 1 is a schematic diagram showing how the thickness of the semiconductor wafer 20 gradually becomes thinner when the back surface of the semiconductor wafer 20 with the adhesive tape 10 attached thereto is ground. In Figure 1, (1) shows the state before backside grinding, (3) shows when the thickness of the semiconductor wafer is about 30 μm, and (2) shows the halfway between the above (1) and the above (3) look. Generally, as shown in FIG. 1 (1), the side surface of the semiconductor wafer 20 before grinding is rounded. The adhesive tape 10 protects the circuit on the surface of the wafer and includes a flat and hard material that can usually stabilize the wafer and the chip. Therefore, once the adhesive tape 10 is attached to the wafer 20 before grinding, as shown in FIG. 1 ( 1 ), a region where the adhesive tape is not in close contact occurs slightly on the outer edge of the wafer 20 .

As shown in Fig. 1, as the wafer backside grinding (1), (2), and (3) progresses, the thickness of the semiconductor wafer 20 becomes thinner and the size changes, but the size of the adhesive tape 10 does not change . Then, once the backside of the wafer is ground and thinned down to about 30 μm, as shown in FIG. 1 (3), the rounded portion of the side of the wafer 20 is removed. In this way, even if the shape of the adhesive tape is set to be approximately the same as that of the wafer before grinding as shown in FIG. 1 (1), after grinding, the outer edge of the adhesive tape 10 is in The outer peripheral portion of wafer 20 is exposed. In this state, when the adhesive tape is irradiated with energy rays such as ultraviolet rays, the adhesive force is sufficiently reduced at the portion of the adhesive tape that is in close contact with the wafer. However, in the portion of the adhesive tape that is not in close contact with the wafer and is exposed to the atmosphere (the exposed portion of the outer edge), the hardening of the adhesive is hindered by oxygen in the atmosphere, and even if it is irradiated with energy rays such as ultraviolet rays, the adhesion force has not yet been sufficiently reduced. That is, the adhesive tape has a portion that has not yet hardened after being irradiated with energy rays such as ultraviolet rays.

For example, a dicing/die bonding tape is attached as an adhesive tape to the back surface of the wafer after back grinding. 2 and 3 are schematic diagrams of a laminated body in which a dicing/die bonding tape 30 is attached to a ground semiconductor wafer 20 on the backside of which the adhesive tape 10 is attached. The dicing/die bonding tape 30 includes an adhesive layer (not shown) by which it is attached to the semiconductor wafer 20 . FIG. 3 shows a state where a dicing/die-bonding tape 30 is attached to a backside-ground semiconductor wafer 20 as thin as about 30 μm. On the other hand, FIG. 2 shows the state after the semiconductor wafer 20 is attached with the dicing/die bonding tape 30 and the thickness of the semiconductor wafer 20 is greater than that in FIG. 3 . As shown in FIG. 2, when the thickness of the semiconductor wafer 20 after backside grinding is large, even if the dicing/die-bonding tape 30 is attached, the unhardened portion of the adhesive tape 10 does not contact the dicing/die-bonding tape. 30 adhesive layer. However, as shown in FIG. 3, when the thickness of the backside-ground semiconductor wafer 20 is extremely thinned to about 30 μm, once the dicing/die bonding tape 30 is attached, the unhardened portion of the adhesive tape 10 will There is a risk of contacting and sticking to the adhesive layer of the dicing/die bonding tape 30 . Dicing/die bonding tapes are not cut like wafers. Therefore, once the adhesive tape attached to the dicing/die bonding tape is to be peeled off, the adhesive tape and the dicing/die bonding tape are integrated, and the dicing/die bonding tape will also bend along with the bending of the adhesive tape, and then , wafers, wafers, etc. sandwiched between the adhesive tape and the dicing/die bonding tape are also bent at the same time. As a result, cracks tend to occur on the wafer. In addition, the adhesive layer of the dicing/die-bonding tape is damaged by bending, and its fragments may fall off.

That is, in the region where the adhesive force of the adhesive tape is not sufficiently reduced even when irradiated with energy rays such as ultraviolet rays, when the thickness of the semiconductor wafer is extremely thinned by back grinding, wafer cracking is likely to occur when the adhesive tape is peeled off. The cracked situation becomes a problem.

The present invention is made in view of the above conventional techniques, and an object of the present invention is to provide an adhesive tape for semiconductor processing that can suppress cracking of a wafer when the adhesive tape is peeled off. [means used to solve a problem]

The gist of the present invention aimed at solving such problems is as follows.

(1) An adhesive tape for semiconductor processing, which is an adhesive tape having a base material and an adhesive layer, in which one side of the adhesive layer is exposed to the atmosphere, and the illuminance is 220mW/cm ² and the light intensity is 500mJ/cm ² . The surface elasticity modulus of the exposed surface of the adhesive layer after the adhesive tape is irradiated with ultraviolet rays is 5 MPa or more.

(2) The adhesive tape for semiconductor processing according to (1), wherein the adhesive layer contains an acrylic resin, The content of the HEMA-derived polymerized units is 6 parts by mass or more relative to 100 parts by mass of the total amount of the acrylic resin.

(3) The adhesive tape for semiconductor processing as described in (1) or (2), wherein the adhesive layer is exposed to the air on one side under the conditions of an illuminance of 220mW/cm ² and a light intensity of 500mJ/cm ² . After the above-mentioned adhesive tape is irradiated with ultraviolet rays, the surface free energy of the exposed surface of this adhesive layer is less than 36 mJ/m ² .

(4) A method of manufacturing a semiconductor device, comprising the following steps: Attach the adhesive tape for semiconductor processing described in any one of the above (1) to (3) on the front surface of the semiconductor wafer, and cut the adhesive tape along the outer periphery of the semiconductor wafer; Forming trenches from the front side of the aforementioned semiconductor wafer, or forming a modified region inside the semiconductor wafer from the front or back side of the aforementioned semiconductor wafer; Grinding the semiconductor wafer with the aforementioned adhesive tape on the front surface and forming the aforementioned groove or the aforementioned modified region, from the back side, and starting from the aforementioned groove or the aforementioned modified region, and individualizing it into a plurality of wafers; and The said adhesive tape was peeled off from the said some wafer.

(5) The method for manufacturing a semiconductor device according to (4), further including the step of attaching a dicing/die bonding tape to the back surface of the semiconductor wafer. [Efficacy of the invention]

With the adhesive tape for semiconductor processing related to the present invention, the adhesive force of the adhesive layer can be sufficiently reduced in the air atmosphere. As a result, the occurrence of cracks in the semiconductor wafer can be suppressed.

[Mode for Carrying Out the Invention]

Hereinafter, the adhesive tape for semiconductor processing concerning this invention is demonstrated concretely. First, main terms used in this specification will be described. 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.

The term "for semiconductor processing" means that it can be used in each step of semiconductor wafer transportation, backside grinding, dicing, and semiconductor wafer pickup. The "front side" of a semiconductor wafer refers to the side on which circuits are formed, and the "back side" refers to the side on which no circuits are formed. Individual slicing of semiconductor wafers refers to dividing the semiconductor wafer into individual circuits to obtain semiconductor wafers.

DBG refers to a method in which a groove of a predetermined depth is formed on the front side of a wafer, and then ground from the back side of the wafer, and the wafer is divided into individual pieces by grinding. The grooves formed on the front side of the wafer are formed by methods such as blade dicing, laser dicing, plasma dicing, and the like. In addition, LDBG is a modified example of DBG, and refers to a method in which a modified region is provided inside a wafer with a laser, and the wafer is divided into individual pieces by utilizing stress during wafer back grinding.

Next, the configuration of each member of the adhesive tape for semiconductor processing according to the present invention will be described in more detail. In addition, the adhesive tape for semiconductor processing related to the present invention may be abbreviated as "adhesive tape".

In this embodiment, as shown in FIG. 4 , the adhesive tape 100 means a laminate including a base material 110 and an adhesive layer 120 . The adhesive tape 100 may have a buffer layer on at least one side of the base material 110 . In addition, it may include other constituent layers than those described above. For example, a primer layer may be formed on the surface of the substrate on the side of the adhesive layer, and a release sheet may be layered on the surface of the adhesive layer to protect the adhesive layer until use. In addition, the substrate may be a single layer or a multilayer. The same applies to the adhesive layer and buffer layer. Hereinafter, the structure of each member of the adhesive tape for semiconductor processing concerning this embodiment is demonstrated in detail.

〇Adhesive layer In the adhesive tape related to this embodiment, after exposing one side of the adhesive layer to the atmosphere and irradiating the adhesive tape with ultraviolet light under the conditions of illuminance 220mW/cm ² and light intensity 500mJ/cm ² , this The surface elastic modulus of the exposed surface of the adhesive layer is 5 MPa, preferably 6 MPa or higher, more preferably 6.5 MPa or higher. By setting the above-mentioned surface elastic modulus in the above-mentioned range, the adhesive force of the adhesive layer can be sufficiently reduced, and as a result, the occurrence of cracks in the wafer can be suppressed. In addition, the upper limit of the surface elastic modulus is not particularly limited, and is usually 17 MPa, preferably 14 MPa.

In the measurement of the above-mentioned surface elastic modulus, irradiation of ultraviolet rays was performed from the base material side. In addition, the surface elastic modulus was measured using an atomic force microscope. Specifically, the adhesive was placed at room temperature on a cantilever (cantilever) (front radius: 2nm, resonance frequency: 70kHz, spring constant: 0.4N/m) set on a silicon nitride raw material in an atomic force microscope. The surface of the layer was dented and separated at a denting amount of 5 nm and a scan rate of 5 Hz. The surface elastic modulus was calculated by fitting with the JKR theoretical formula on the obtained force curve (the horizontal axis represents the amount of deformation of the sample, and the vertical axis represents the measured load). The average value of the values measured at 4096 points in the surface 5 μm×5 μm of the adhesive layer was defined as the surface modulus (MPa).

The above-mentioned surface elastic modulus can be controlled by adjusting the amount of polymerized units derived from 2-hydroxyethyl methacrylate (hereinafter, sometimes abbreviated as HEMA) by preparing the adhesive layer to include an acrylic resin. In particular, the adhesive layer is prepared so that the content of HEMA-derived polymerized units is 6 parts by mass or more with respect to 100 parts by mass of the total acrylic resin, and the surface elastic modulus can be within the above range.

In the adhesive tape related to this embodiment, after exposing one side of the adhesive layer to the atmosphere, and irradiating the adhesive tape with ultraviolet rays under the conditions of illuminance 220mW/cm ² and light intensity 500mJ/cm ² , the exposure of the adhesive layer The surface free energy of the surface is preferably not more than 36 mJ/m ² , more preferably not more than 32 mJ/m ² , more preferably not more than 30 mJ/m ² . From the viewpoint of sufficiently reducing the adhesive force of the adhesive layer, it is preferable to set the above-mentioned surface free energy within the above-mentioned range. In addition, the lower limit of the above-mentioned surface free energy is not particularly limited, and is usually 18 mJ/m ² , preferably 22 mJ/m ² .

In the measurement of the above-mentioned surface free energy, irradiation of ultraviolet rays was performed from the substrate side. In addition, the surface free energy is obtained by measuring the contact angle of various liquid droplets (measurement temperature: 25°C), based on the value of the contact angle, by the Kitazaki-Hata method. Specifically, diiodomethane, 1-bromonaphthalene (1-bromonaphthalene) and distilled water were used as liquid droplets, and the contact angle was measured according to JIS R 3257: 1999 by the static drop method (measurement temperature: 25°C), Based on the value of the contact angle, the surface free energy (mJ/m ² ) was obtained by the Kitazaki-Hata method.

The above-mentioned surface free energy can be controlled by adjusting the adhesive layer to include an acrylic resin and further adjusting the amount of HEMA-derived polymerized units. In particular, the adhesive layer is prepared so that the content of HEMA-derived polymerized units is 6 parts by mass or more with respect to 100 parts by mass of the total acrylic resin, and the surface free energy can be controlled within the above-mentioned range.

In addition, in the adhesive tape related to this embodiment, in the state where one side of the adhesive layer is exposed to the atmosphere, the adhesive tape is irradiated with ultraviolet light under the conditions of illuminance 220mW/cm ² and light intensity 500mJ/cm ² , at 23°C, 50 %RH attaches the PMMA plate to the exposed surface of the adhesive layer with a 2kg roller back and forth once and leaves it for 30 minutes. The peel strength when the adhesive tape is peeled at 180° is preferably below 1600mN/25mm. 1100mN/25mm or less is preferable, 980mN/25mm or less is more preferable, and 800mN/25mm or less is particularly preferable. It is preferable to make the said peeling strength into the said range from a viewpoint of fully reducing the adhesive force of an adhesive layer. In addition, the lower limit of the peel strength is not particularly limited, and is usually 50 mN/25 mm, preferably 80 mN/25 mm.

In addition, in the measurement of the above-mentioned peel strength, irradiation of ultraviolet rays was performed from the base material side. In addition, PMMA is polymethyl methacrylate, and as said PMMA plate, the Mitsubishi Chemical Corporation "ACRYLITE L001" with thickness 2mm, width 70mm, and length 150mm was used. The above-mentioned peel strength was measured under the conditions of an adhesive tape width of 25 mm, a peel speed of 300 mm/min, and a measurement temperature of 25° C., and the average value when the measurement was repeated twice under the same conditions was taken as this peel strength.

The above-mentioned peel strength can be controlled by preparing the adhesive layer to contain an acrylic resin and further adjusting the amount of HEMA-derived polymerized units. In particular, the adhesive layer is prepared so that the content of HEMA-derived polymerized units is 6 parts by mass or more with respect to 100 parts by mass of the total acrylic resin, and the peel strength can be controlled within the above range.

In addition, in the adhesive tape related to this embodiment, after exposing one side of the adhesive layer to the atmosphere, the adhesive tape is irradiated with ultraviolet light under the conditions of illuminance 220mW/cm ² and light intensity 500mJ/cm ² . The adhesion energy of the exposed surface of the agent layer is preferably 0.220 J/m ² or less, more preferably 0.200 J/m ² or less, more preferably 0.190 J/m ² or less. From the viewpoint of sufficiently reducing the adhesive force of the adhesive layer, it is preferable to set the above-mentioned adhesive energy within the above-mentioned range. In addition, the lower limit of the above-mentioned adhesive energy is not particularly limited, and is usually 0.12 J/m ² , preferably 0.14 J/m ² .

In the measurement of the above-mentioned adhesive energy, irradiation of ultraviolet rays was performed from the base material side. In addition, adhesion energy was measured using the atomic force microscope. Specifically, a cantilever (tip radius: 2nm, resonance frequency: 70kHz, spring constant: 0.4N/m) installed on a silicon nitride raw material in an atomic force microscope was used to place the surface of the adhesive layer at room temperature. Indentation and separation were performed with an indentation amount of 5 nm and a scan rate of 5 Hz. For the obtained force curve (the horizontal axis is the deformation of the sample, and the vertical axis is the measured load), fit it with the JKR theoretical formula to calculate the adhesion energy. The average value of the values measured at 4096 points on the surface of the adhesive layer of 5 μm×5 μm was defined as the adhesive energy (J/m ² ).

The above adhesive energy can be controlled by preparing the adhesive layer to include an acrylic resin and further adjusting the amount of HEMA-derived polymerized units. In particular, the adhesive layer is prepared so that the content of HEMA-derived polymerized units is 6 parts by mass or more with respect to 100 parts by mass of the total acrylic resin, and the adhesive energy can be controlled within the above-mentioned range.

The thickness of the adhesive layer is not particularly limited as long as the peeling strength after ultraviolet irradiation in the state where the adhesive layer is exposed to the atmosphere as described above is 1600 mN/25 mm or less, but it is preferably less than 100 μm, preferably 5 to 80 μm is better, more preferably 10~70μm.

In addition, the adhesive layer is not particularly limited as long as the peeling strength after ultraviolet irradiation in the state exposed to the air atmosphere is 1600 mN/25 mm or less, but is preferably formed of an acrylic adhesive. In addition, the adhesive layer is preferably formed of an energy ray curable adhesive. In addition, the so-called "energy rays" refer to ultraviolet rays, electron rays, etc., and it is preferable to use ultraviolet rays.

Hereinafter, specific examples of the adhesive will be described in detail, but these are non-limiting illustrations, and the adhesive layer in the present invention should not be limitedly interpreted as these specific examples. [adhesive composition]

As the energy ray-curable adhesive for forming the adhesive layer, for example, the following energy ray-curable adhesive composition (hereinafter, also referred to as "X-type adhesive composition") can be used: In addition to adhesive resins (also called "adhesive resin I"), there are energy ray-curable compounds other than adhesive resins. In addition, as an energy ray-curable adhesive, an energy ray-curable adhesive resin containing an unsaturated group introduced into a side chain of a non-energy ray-curable adhesive resin (hereinafter also referred to as "adhesive resin") can also be used. II") is an adhesive composition that does not contain an energy ray-curable compound other than an adhesive resin as a main component (hereinafter also referred to as "Y-type adhesive composition").

In addition, as the energy ray-curable adhesive, it is also possible to use a combined type of X type and Y type, that is, an energy ray-curable compound other than the adhesive resin in addition to the energy ray-curable adhesive resin II. Energy ray-curable adhesive composition (hereinafter also referred to as "XY-type adhesive composition"). Among these, it is preferable to use an XY-type adhesive composition. The XY type has sufficient adhesive properties before curing, but after curing, the peeling strength to the semiconductor wafer can be sufficiently reduced.

However, the adhesive may be formed from a non-energy ray-curable adhesive composition that does not harden even when irradiated with energy rays. The non-energy ray-curable adhesive composition contains at least the non-energy ray-curable adhesive resin I, and on the other hand, does not contain the above-mentioned energy ray-curable adhesive resin II and the energy ray-curable compound.

In addition, "adhesive resin" in the following description is used as a term referring to one or both of the above-mentioned adhesive resin I and adhesive resin II. Specific adhesive resins include, for example, acrylic resins, urethane resins, rubber resins, silicone resins, etc., but acrylic resins are preferred. Hereinafter, an acrylic adhesive using an acrylic resin as an adhesive resin will be described in detail.

Among the acrylic resins, acrylic polymers are used. The acrylic polymer is obtained by polymerizing a monomer containing at least an alkyl (meth)acrylate, and contains a structural unit derived from an alkyl (meth)acrylate. Examples of the alkyl (meth)acrylate include those having 1 to 20 carbon atoms in the alkyl group, 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 methacrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, (meth) Decyl acrylate, undecyl (meth)acrylate, lauryl (meth)acrylate, etc. Alkyl (meth)acrylate can be used individually or in combination of 2 or more types.

In addition, from the viewpoint of enhancing the adhesive force of the adhesive layer, the acrylic polymer preferably contains a constituent unit derived from an alkyl group having a carbon number of 4 or more alkyl (meth)acrylate. As carbon number of this alkyl (meth)acrylate, 4-12 are preferable, and 4-6 are more preferable. In addition, the alkyl (meth)acrylate having an alkyl group having 4 or more carbon atoms is preferably an alkyl acrylate.

In an acrylic polymer, the content of an alkyl (meth)acrylate having an alkyl group having 4 or more carbon atoms is 100% by mass relative to the total amount of monomers constituting the acrylic polymer (hereinafter referred to as "the total amount of monomers") Parts, preferably 35 to 98 parts by mass, more preferably 45 to 95 parts by mass, more preferably 50 to 90 parts by mass.

The acrylic polymer is a structural unit derived from an alkyl (meth)acrylate with an alkyl group having 4 or more carbon atoms. In order to adjust the elastic modulus and adhesive properties of the adhesive layer, the carbon number of the alkyl group is 1 to 1. Copolymers of constituent units derived from alkyl (meth)acrylates of 3 are preferred. In addition, 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 the alkyl (meth)acrylate with an alkyl group having 1 to 3 carbon atoms is preferably 1 to 30 parts by mass, preferably 3 to 26 parts by mass, relative to 100 parts by mass of the total amount of monomers. Parts by mass are preferred, more preferably 5 to 22 parts by mass.

The acrylic polymer preferably has a structural unit derived from a functional group-containing monomer in addition to the above-mentioned structural unit derived from an alkyl (meth)acrylate. As a functional group of a functional group containing monomer, a hydroxyl group, a carboxyl group, an amino group, an epoxy group etc. are mentioned. The functional group-containing monomer can react with the following crosslinking agent to become a crosslinking origin, or react with an unsaturated group-containing compound to introduce an unsaturated group into the side chain of the acrylic polymer.

Examples of the functional group-containing monomer include a hydroxyl group-containing monomer, a carboxyl group-containing monomer, an amino group-containing monomer, an epoxy group-containing monomer, and the like. In this embodiment, it is particularly preferable to use HEMA in a predetermined amount or more as the functional group-containing monomer.

Here, in the adhesive tape according to this embodiment, it is preferable that the adhesive layer contains an acrylic resin, and the content of HEMA-derived polymerized units is 6 parts by mass or more based on 100 parts by mass of the total amount of the acrylic resin. The content of HEMA-derived polymer units may further be 10 parts by mass or more or 12 parts by mass or more. In the preparation of the adhesive layer, the content of the HEMA-derived polymerized unit is used within the above-mentioned range, and the above-mentioned peel strength, surface free energy, surface elastic modulus, and adhesive energy for the adhesive can be set within the desired range. Also, the upper limit of the HEMA-derived polymerized unit content in the adhesive layer is not particularly limited, but it is usually 35 parts by mass, preferably 32 parts by mass, based on 100 parts by mass of the total acrylic resin.

In this embodiment, hydroxyl group-containing monomers other than HEMA, carboxyl group-containing monomers, amino group-containing monomers, epoxy group-containing monomers, and the like can be used alone or in combination of two or more. Among these, it is preferable to use a hydroxyl group-containing monomer and a carboxyl group-containing monomer, and it is more preferable to use a hydroxyl group-containing monomer.

Examples of hydroxyl-containing monomers other than HEMA include: 2-hydroxyethyl acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, (meth)acrylic acid Hydroxyalkyl (meth)acrylates such as 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; unsaturated alcohols such as vinyl alcohol and acrylic alcohol, etc.

Examples of carboxyl group-containing monomers include ethylenically unsaturated monocarboxylic acids such as (meth)acrylic acid and crotonic acid; fumaric acid, itaconic acid, maleic acid, citraconic acid, etc. Ethylenically unsaturated dicarboxylic acid and its anhydride, 2-carboxyethyl methacrylate, etc.

The content of the functional group-containing monomer other than HEMA is preferably 1 to 35 parts by mass, more preferably 3 to 32 parts by mass, and 6 to 30 parts by mass relative to 100 parts by mass of the total monomers constituting the acrylic polymer. Servings are better. In addition, in addition to the above, the acrylic polymer may contain styrene, α-methylstyrene, vinyl toluene, vinyl formate, vinyl acetate, acrylonitrile, acrylamide, etc., which are copolymerizable with the above-mentioned acrylic monomers. monomer-derived building blocks.

The above acrylic polymer can be used as the non-energy ray curable adhesive resin I (acrylic resin). Also, examples of energy ray-curable acrylic resins include those in which the functional groups of the above-mentioned acrylic polymer I react with compounds having photopolymerizable unsaturated groups (so-called unsaturated group-containing compounds).

The unsaturated group-containing compound is a compound having both of a substituent capable of bonding to a functional group of an acrylic polymer and a photopolymerizable unsaturated group. Examples of photopolymerizable unsaturated groups include (meth)acryl groups, vinyl groups, propenyl groups, vinylbenzyl groups, and the like, with (meth)acryl groups being preferred. Moreover, an isocyanate group, a glycidyl group, etc. are mentioned as a substituent which has a compound containing an unsaturated group and can bond with a functional group. Therefore, examples of the unsaturated group-containing compound include (meth)acryl oxiranyl isocyanate, (meth)acryl isocyanate, and glycidyl (meth)acrylate.

In addition, it is preferable that the unsaturated group-containing compound reacts with a part of the functional group of the acrylic polymer. It is better to react the compound of base, so that the reaction of 55-93 mole % is better. In this way, in the energy ray-curable acrylic resin, some functional groups remain without reacting with the unsaturated group-containing compound, and it becomes easy to crosslink with the crosslinking agent. In addition, the weight average molecular weight (Mw) of the acrylic resin is preferably from 300,000 to 1.6 million, more preferably from 400,000 to 1.4 million, and more preferably from 500,000 to 1.2 million. (energy ray hardening compound)

The energy ray-curable compound contained in the X-type or XY-type adhesive composition is preferably a monomer or oligomer that has an unsaturated group in the molecule and can be polymerized and cured by energy ray irradiation. Examples of such energy ray-curable compounds include trimethylolpropane tri(meth)acrylate, neopentylitol (meth)acrylate, neopentylitol tetra(meth)acrylate, Polyvalent (meth)acrylic acid such as dipenteoerythritol hexa(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol (meth)acrylate, etc. Oligomers of ester monomers, urethane (meth)acrylates, polyester (meth)acrylates, polyether (meth)acrylates, epoxy (meth)acrylates, etc.

Among these, urethane (meth)acrylate oligomers are preferable in terms of relatively high molecular weight and the viewpoint that the shear storage modulus of the adhesive layer is not easily lowered. The molecular weight of the energy ray-curable compound (weight average molecular weight in the case of an oligomer) is preferably 100-12,000, more preferably 200-10,000, more preferably 400-8,000, and particularly preferably 600-6,000.

The content of the energy ray-curable compound in the type X adhesive composition is preferably 40 to 200 parts by mass, more preferably 50 to 150 parts by mass, and 60 to 90 parts by mass relative to 100 parts by mass of the adhesive resin. Servings are better. On the other hand, the content of the energy ray-curable compound in the XY-type adhesive composition is preferably 1 to 30 parts by mass, more preferably 2 to 20 parts by mass, with respect to 100 parts by mass of the adhesive resin. 3-15 mass parts are more preferable. In the XY type adhesive composition, since the adhesive resin is energy ray curable, even if the content of the energy ray curable compound is small, the peel strength can be sufficiently reduced after energy ray irradiation. (crosslinking agent)

The adhesive composition preferably further contains a crosslinking agent. The crosslinking agent is, for example, one that reacts with a functional group derived from a functional group-containing monomer contained in the adhesive resin to crosslink the adhesive resins. Examples of the crosslinking agent include isocyanate-based crosslinking agents such as toluene diisocyanate, hexamethylene diisocyanate, and the above-mentioned adducts, and epoxy-based crosslinking agents such as ethylene glycol glycidyl ether. ; Aziridine-based cross-linking agents such as hexa[1-(2-methyl)-aziridinyl]triphosphite triazine; chelating-based cross-linking agents such as aluminum chelates, etc. These crosslinking agents can be used alone or in combination of two or more.

Among these, isocyanate-based crosslinking agents are preferable from the viewpoint of improving cohesive strength to increase adhesive strength, and from the viewpoint of ease of acquisition and the like. The compounded amount of the crosslinking agent is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 7 parts by mass, and 0.05 to 4 parts by mass relative to 100 parts by mass of the adhesive resin from the viewpoint of accelerating the crosslinking reaction. Servings are better. (photopolymerization initiator)

Also, when the adhesive composition is energy ray curable, it is preferable that the adhesive composition further contains a photopolymerization initiator. By containing the photopolymerization initiator, even with relatively low-energy energy rays such as ultraviolet rays, the hardening reaction of the adhesive composition can be sufficiently advanced.

Examples of photopolymerization initiators include benzoin compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, thioxanthone compounds, peroxide compounds, and Photosensitizers such as amines and quinones, and more specifically, 1-hydroxycyclohexylbenzophenone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, benzoin , benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl benzene sulfide, tetramethylammonium thioformyl monosulfide, azobisisobutyronitrile, bibenzyl, diacetyl, 8-chloroanthraquinone, bis( 2,4,6-trimethylbenzyl)phenylphosphine, 2,2-dimethoxy-2-phenylacetophenone, etc.

These photopolymerization initiators can be used individually or in combination of 2 or more types. The compounding quantity of a photoinitiator is preferably 0.01-10 mass parts with respect to 100 mass parts of adhesive resins, More preferably, it is 0.03-5 mass parts, More preferably, it is 0.05-5 mass parts. (other additives)

The adhesive composition may contain other additives in the range which does not impair the effect of this invention. Examples of other additives include antistatic agents, antioxidants, softeners (plasticizers), fillers, antirust agents, pigments, and dyes. When compounding these additives, the compounding amount of the additives is preferably 0.01 to 6 parts by mass relative to 100 parts by mass of the adhesive resin.

In addition, from the viewpoint of improving applicability to substrates, buffer layers, release sheets, etc., the adhesive composition may be further diluted with an organic solvent to be in the form of a solution of the adhesive composition. Examples of the organic solvent include butanone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexane, n-hexane, toluene, xylene, n-propanol, isopropanol and the like. In addition, these organic solvents may be used as the organic solvents used in the synthesis of the adhesive resin, or one or more organic solvents other than the organic solvents used in the synthesis may be added to make a solution of the adhesive composition Can be evenly coated. 〇Substrate

The Younger's modulus of the substrate at 23°C is preferably above 1000MPa. Once a substrate with a Younger modulus of less than 1000MPa is used, the adhesive tape’s stability to the semiconductor wafer or semiconductor wafer will be reduced, and the vibration during back grinding cannot be suppressed, and the semiconductor wafer is prone to chipping and damage. On the other hand, if the Younger's modulus of the base material at 23°C is set to 1000 MPa or more, the adhesive tape can improve the stability of the semiconductor wafer or the semiconductor wafer, and can suppress vibration during back grinding, and can prevent the semiconductor wafer from cracking. Defects, breakage, etc. Moreover, the stress at the time of peeling the adhesive tape from the semiconductor wafer can be reduced, and it is possible to prevent wafer chipping, breakage, and the like that occur when the tape is peeled off. In addition, the workability at the time of attaching the adhesive tape to the semiconductor wafer can also be improved. From this point of view, the Younger's modulus of the substrate at 23° C. is preferably 1800-30000 MPa, more preferably 2500-6000 MPa.

The thickness of the substrate is not particularly limited, but is preferably 110 μm or less, more preferably 15-110 μm, more preferably 20-105 μm. When the thickness of the base material is 110 μm or less, it is easy to control the peel strength of the adhesive tape. Moreover, when it is 15 micrometers or more, a base material becomes easy to fulfill the function as the support body of an adhesive tape.

As a material of a base material, if it satisfies the said physical property, it will not specifically limit, and various resin films can be used. Here, examples of substrates having a Younger modulus at 23°C of 1000 MPa or more include polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, wholly aromatic Polyester such as polyester; polyimide, polyamide, polycarbonate, polyacetal, modified polyphenylene ether, polyphenylene sulfide, polysulfide, polyether ketone, biaxially extended poly Resin films such as acrylic. Among these resin films, it is preferable to include one or more films selected from polyester films, polyamide films, polyimide films, and biaxially stretched polypropylene films, preferably to include polyester films, to include A polyethylene terephthalate film is more preferred.

In addition, the substrate may contain plasticizers, lubricants, infrared absorbers, ultraviolet absorbers, fillers, colorants, antistatic agents, antioxidants, catalysts, etc. within the range that does not impair the effects of the present invention. Furthermore, the substrate may be transparent or opaque, and may be colored or vapor-deposited as required. In addition, at least one surface of the substrate may be subjected to an adhesive treatment such as corona treatment in order to improve the adhesion to at least one of the buffer layer and the adhesive layer. Moreover, the base material may have the above-mentioned resin film, and the easy-adhesion layer formed on at least one surface of the resin film via a film.

The easily-adhesive layer-forming composition for forming the easily-adhesive layer is not particularly limited, and examples thereof include combinations containing polyester-based resins, urethane-based resins, polyester-urethane-based resins, and acrylic resins. thing. The composition for forming an easily-adhesive layer may contain a crosslinking agent, a photopolymerization initiator, an antioxidant, a softener (plasticizer), a filler, an antirust agent, a pigment, a dye, and the like as necessary. The thickness of the easily-adhesive layer is preferably 0.01 to 10 μm, more preferably 0.03 to 5 μm. In addition, since the thickness of the easy-adhesive layer in the embodiment of the present application is smaller than the thickness of the base material, the thickness of the resin film with the easy-adhesive layer is substantially the same as the thickness of the base material. In addition, since the material of the easy-adhesive layer is soft and has little influence on the Younger's modulus, the Younger's modulus of the base material is substantially the same as that of the resin film even when the easily-adhesive layer is provided.

For example, the Younger's modulus of the substrate can be regulated by the choice of resin composition, the addition of plasticizers, and the stretching conditions during the manufacture of resin films. Specifically, when a polyethylene terephthalate film is used as the base material, the Younger modulus of the base material tends to decrease when the content ratio of the ethylene component in the copolymerization component increases. Also, when the amount of the plasticizer compounded is increased relative to the resin composition constituting the base material, the Young's modulus of the base material tends to decrease. 〇Buffer layer

The adhesive tape according to this embodiment may have a buffer layer. The buffer layer may be provided on at least one side of the substrate, or may be provided on both sides of the substrate. In addition, an adhesive layer may be provided on one side of the substrate, and a buffer layer may be provided on the other side of the substrate.

The buffer layer relieves stress during grinding of the back surface of the semiconductor wafer and prevents cracks and defects from occurring on the semiconductor wafer. After attaching the adhesive tape to the semiconductor wafer and cutting the adhesive tape along the outer periphery, the semiconductor wafer is placed on the chuck base through the adhesive tape and subjected to back grinding. The adhesive tape has a buffer layer as a constituent layer, which is easy to Secure the semiconductor wafer properly in the chuck holder.

The buffer layer is a softer layer than the base material. Therefore, the Young's modulus of the buffer layer at 23°C is smaller than that of the substrate at 23°C. Specifically, the Younger's modulus of the buffer layer at 23° C. is preferably less than 1000 MPa, preferably less than 700 MPa, more preferably less than 500 MPa.

The thickness of the buffer layer is preferably 1-100 μm, more preferably 5-80 μm, more preferably 10-60 μm. By setting the thickness of the buffer layer within the above range, it is possible to appropriately relax the stress of the buffer layer during back grinding.

The cushion layer is preferably a cured product of a composition for forming a cushion layer containing an energy ray polymerizable compound. Moreover, it may be a layer containing a polyolefin resin film, or may be a layer using polyether as a main ingredient. Hereinafter, each component contained in the layer formed from the buffer layer-forming composition containing an energy ray polymerizable compound, and each component contained in a layer containing a polyolefin resin film will be described in order. <A layer formed from a buffer layer-forming composition containing an energy ray polymerizable compound>

The buffer layer-forming composition containing an energy ray polymerizable compound can be cured by irradiating energy rays. Moreover, it is preferable that the composition for forming a buffer layer containing an energy ray polymerizable compound more specifically contains urethane (meth)acrylate (a1). In addition, the composition for forming a buffer layer may contain, in addition to the above (a1), a polymerizable compound (a2) having an alicyclic group or a heterocyclic group having 6 to 20 ring-forming atoms and/or a polymerizable compound having a functional group. Compound (a3) is preferred. Moreover, the composition for buffer layer formation may contain a polyfunctional polymeric compound (a4) other than said (a1)-(a3) component. In addition, the buffer layer forming composition preferably contains a photopolymerization initiator, but may contain other additives, resin components, etc. within the range that does not impair the effect of the present invention. Hereinafter, each component contained in the composition for forming a buffer layer containing an energy ray polymerizable compound will be described in detail. (Urethane (meth)acrylate (a1))

Urethane (meth)acrylate (a1) refers to a compound having at least a (meth)acryl group and a urethane bond, and is a compound that has the property of being polymerized and hardened by energy ray irradiation . The urethane (meth)acrylate (a1) is an oligomer or a polymer.

The weight average molecular weight (Mw) of the component (a1) is preferably 1,000-100,000, more preferably 2,000-60,000, more preferably 10,000-30,000. Also, the number of (meth)acryl groups in component (a1) (hereinafter also referred to as "functional group") may be monofunctional, difunctional, or more than trifunctional, preferably monofunctional or difunctional. The component (a1) can be obtained, for example, by reacting a (meth)acrylate having a hydroxyl group with an isocyanate-terminated urethane prepolymer obtained by reacting a polyol compound and a polyvalent isocyanate compound. Moreover, a component (a1) can be used individually or in combination of 2 or more types.

The polyol compound used as a raw material for the component (a1) is not particularly limited as long as it has two or more hydroxyl groups. As a specific polyol compound, an alkylene glycol, a polyether polyol, a polyester polyol, a polycarbonate polyol, etc. are mentioned, for example. Among these, polyester polyol or polycarbonate polyol is preferable. In addition, as the polyol compound, it can be any one of difunctional diol, trifunctional triol, and tetrafunctional or higher polyol, preferably difunctional diol, polyester diol or polycarbonate Type diols are preferred.

Examples of polyvalent isocyanate compounds include aliphatic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate; Alicyclic diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, ω,ω'-diisocyanate dimethylcyclohexane, etc. Isocyanates; 4,4'-diphenylmethane diisocyanate, toluene diisocyanate, xylylene diisocyanate, benzylidine diisocyanate, tetramethylene xylylene diisocyanate, naphthalene- Aromatic diisocyanates such as 1,5-diisocyanate, etc. Among these, isophorone diisocyanate, hexamethylene diisocyanate, and xylylene diisocyanate are preferable.

Urethane (meth)acrylate can be obtained by reacting a (meth)acrylate having a hydroxyl group with an isocyanate-terminated urethane prepolymer obtained by reacting the above-mentioned polyol compound and a polyisocyanate compound. (a1). The (meth)acrylate having a hydroxyl group is not particularly limited as long as it has a hydroxyl group and a (meth)acryl group in at least one molecule.

Specifically, examples of (meth)acrylates having a hydroxyl group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 4-Hydroxycyclohexyl (meth)acrylate, 5-Hydroxycyclohexyl (meth)acrylate, 2-Hydroxy-3-phenoxypropyl (meth)acrylate, Neopentylthritol tri(methyl) Hydroxyalkyl (meth)acrylates of acrylates, polyethylene glycol mono(meth)acrylates, polypropylene glycol mono(meth)acrylates, etc.; N-methylol (meth)acrylamide, etc. containing hydroxyl groups (meth)acrylamide; reactants obtained by reacting vinyl alcohol, vinyl phenol, and bisphenol A with (meth)acrylic acid, etc. Among these, hydroxyalkyl (meth)acrylate is preferable, and 2-hydroxyethyl (meth)acrylate is preferable.

As a condition for reacting the isocyanate-terminated urethane prepolymer with the (meth)acrylate having a hydroxyl group, it is necessary to react at 60~100°C for 1~ 4 hours is the best condition. The content of the component (a1) in the composition for buffer layer formation is preferably 10 to 70 parts by mass, more preferably 20 to 60 parts by mass relative to the total amount (100 parts by mass) of the composition for buffer layer formation. (Polymerizable compound (a2) having an alicyclic or heterocyclic group with 6 to 20 ring-forming atoms)

Component (a2) is a polymerizable compound having an alicyclic or heterocyclic group with ring-forming atoms of 6 to 20, preferably a compound having at least one (meth)acryl group, preferably one (meth)acryl group. base) acryl-based compounds. By using the component (a2), the film-forming properties of the obtained composition for buffer layer formation can be improved.

In addition, the definition of component (a2) overlaps with the definition of component (a3) described later, but the overlapping part is included in component (a3). For example, a compound having at least one (meth)acryl group, an alicyclic group or a heterocyclic group with 6 to 20 ring-forming atoms, and a functional group such as a hydroxyl group, an epoxy group, an amido group, an amino group, etc. The definition of both the component (a2) and the component (a3) is included, but in the present invention, these compounds are included in the component (a3).

The number of ring-forming atoms of the alicyclic or heterocyclic group contained in the component (a2) is preferably 6-20, more preferably 6-18, more preferably 6-16, particularly preferably 7-12. Examples of atoms forming the ring structure of the heterocyclic group include carbon atoms, nitrogen atoms, oxygen atoms, sulfur atoms and the like. In addition, the so-called number of ring-forming atoms refers to the number of atoms constituting the ring itself in a compound having a structure in which atoms are bonded in a ring, and atoms not constituting the ring (such as hydrogen atoms bonded to atoms constituting the ring) ), this ring is the atoms contained in the substituent when it is substituted by a substituent, etc., and the number of atoms forming the ring is not included.

Specific examples of the component (a2) include isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentyl (meth)acrylate, and dicyclopentanyl (meth)acrylate. Alicyclic group-containing (meth)acrylates such as alkenyloxyester, cyclohexyl (meth)acrylate, and adamantyl (meth)acrylate; tetrahydrofurfuryl (meth)acrylate, (meth)acrylic acid Heterocyclic group-containing (meth)acrylates such as morphephrine, etc. Moreover, a component (a2) can be used individually or in combination of 2 or more types. Among the (meth)acrylates containing alicyclic groups, isocamphoryl (meth)acrylate is preferred; among the (meth)acrylates containing heterocyclic groups, tetrahydro(meth)acrylate is preferred. Furfuryl ester is preferred.

The content of the component (a2) in the composition for buffer layer formation is preferably 10 to 80 parts by mass, more preferably 20 to 70 parts by mass relative to the total amount (100 parts by mass) of the composition for buffer layer formation. (Polymerizable compound (a3) having a functional group)

Component (a3) is a polymerizable compound containing functional groups such as hydroxyl group, epoxy group, amido group, amino group, etc., and preferably has at least one (meth)acryl group, preferably has one (Meth)acryloyl compounds. The compatibility of component (a3) and component (a1) is good, and it is easy to adjust the viscosity of the composition for buffer layer formation in an appropriate range. Also, even if the buffer layer is made thin, the buffer performance is good. Examples of the component (a3) include hydroxyl group-containing (meth)acrylates, epoxy group-containing compounds, amide group-containing compounds, amino group-containing (meth)acrylates, and the like.

Examples of hydroxyl-containing (meth)acrylates include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, (meth)acrylate base) 2-hydroxybutyl acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, phenylhydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate -3-phenoxypropyl ester, etc. As an epoxy group-containing compound, for example, glycidyl (meth)acrylate, methylglycidyl (meth)acrylate, allyl glycidyl ether, etc., among these, ( Epoxy group-containing (meth)acrylates such as glycidyl meth)acrylate and methylglycidyl (meth)acrylate are preferable. Examples of compounds containing amide groups include (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-butyl(meth)acrylamide, N-hydroxyl Methyl(meth)acrylamide, N-methylolpropane(meth)acrylamide, N-methoxymethyl(meth)acrylamide, N-butoxymethyl(methyl) Acrylamide etc. Examples of amino group-containing (meth)acrylates include primary amino group-containing (meth)acrylates, secondary amino group-containing (meth)acrylates, tertiary amino group-containing (meth)acrylates, and tertiary amino group-containing (meth)acrylates. ) acrylates, etc.

Among these, hydroxyl-containing (meth)acrylates are preferable, and hydroxyl-containing (meth)acrylates having an aromatic ring such as phenylhydroxypropyl (meth)acrylate are preferable. Moreover, a component (a3) can be used individually or in combination of 2 or more types.

The content of the component (a3) in the buffer layer-forming composition is 5 to 40 mass parts relative to the total amount (100 parts by mass) of the buffer layer-forming composition in order to improve the film-forming properties of the buffer layer-forming composition. Parts are better, preferably 7 to 35 parts by mass, more preferably 10 to 30 parts by mass. In addition, the content ratio [(a2)/(a3)] of the component (a2) to the component (a3) in the buffer layer forming composition is preferably 0.5 to 3.0, more preferably 1.0 to 3.0, more preferably 1.3~3.0, especially 1.5~2.8. (polyfunctional polymerizable compound (a4))

The term "polyfunctional polymerizable compound" refers to a compound having two or more photopolymerizable unsaturated groups. The photopolymerizable unsaturated group is a functional group containing a carbon-carbon double bond, and examples thereof include a (meth)acryl group, a vinyl group, an allyl group, and a vinylbenzyl group. A photopolymerizable unsaturated group may combine 2 or more types. The photopolymerizable unsaturated group in the polyfunctional polymerizable compound reacts with the (meth)acryl group in component (a1), or the photopolymerizable unsaturated group in component (a4) reacts with each other, and Able to form a three-dimensional network structure (cross-linked structure). When using a polyfunctional polymerizable compound, compared to using a compound containing only one photopolymerizable unsaturated group, it is easier to increase the crosslinked structure formed by energy ray irradiation.

In addition, the definition of component (a4) overlaps with the definitions of components (a2), (a3) and the like described above, but the overlapping part is included in component (a4). For example, a compound having an alicyclic or heterocyclic group with 6 to 20 ring-forming atoms and two or more (meth)acryloyl groups is included in the definitions of both component (a4) and component (a2), However, in the present invention, this compound is included in the component (a4). In addition, compounds containing functional groups such as hydroxyl groups, epoxy groups, amido groups, and amino groups and having two or more (meth)acryloyl groups are included in the definitions of both component (a4) and component (a3), However, in the present invention, this compound is included in the component (a4).

From the above viewpoint, the number of photopolymerizable unsaturated groups (functional group number) in the polyfunctional polymerizable compound is preferably 2-10, more preferably 3-6.

Moreover, the weight average molecular weight of component (a4) is preferably 30-40000, more preferably 100-10000, more preferably 200-1000.

Specific examples of the component (a4) include diethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, neopentyl di(meth)acrylate, Alcohol Di(meth)acrylate, 1,6-Hexanediol Di(meth)acrylate, Trimethylolpropane Tri(meth)acrylate, Neopentylthritol Tri(meth)acrylate, Neo Pentaerythritol tetra(meth)acrylate, dipenteoerythritol hexa(meth)acrylate, divinylbenzene, vinyl (meth)acrylate, divinyl adipate, N,N'-methylene Bis(meth)acrylamide, etc. Moreover, component (a4) can be used individually or in combination of 2 or more types. Among these, dipenteoerythritol hexa(meth)acrylate is preferable.

The content of the component (a4) in the composition for forming a buffer layer is preferably 2 to 40 parts by mass, more preferably 3 to 20 parts by mass, more preferably Preferably, it is 5 to 15 parts by mass. (Polymerizable compound (a5) other than components (a1) to (a4))

The composition for buffer layer formation may contain the other polymeric compound (a5) other than the said component (a1)-(a4) in the range which does not impair the effect of this invention. Examples of the component (a5) include alkyl (meth)acrylates having an alkyl group having 1 to 20 carbon atoms; styrene, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, and N-vinylformamide Vinyl compounds such as N-vinylpyrrolidone and N-vinylcaprolactam, etc. Moreover, a component (a5) can be used individually or in combination of 2 or more types.

The content of the component (a5) in the composition for forming a buffer layer is preferably 0 to 20 parts by mass, more preferably 0 to 10 parts by mass, more preferably Preferably, it is 0-5 mass parts, and especially preferably, it is 0-2 mass parts. (photopolymerization initiator)

The buffer layer-forming composition preferably further contains a photopolymerization initiator from the viewpoint of shortening the polymerization time by light irradiation when forming a buffer layer and reducing the amount of light irradiation.

Examples of photopolymerization initiators include benzoin compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, thioxanthone compounds, peroxide compounds, amines, Photosensitizers such as benzoquinone, etc., more specifically, 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, azobisisobutyronitrile, dibenzyl, diethyl Acyl, 8-chloroanthraquinone, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, etc.

These photopolymerization initiators can be used individually or in combination of 2 or more types.

The content of the photopolymerization initiator in the composition for forming a buffer layer is preferably 0.05 to 15 parts by mass, more preferably 0.1 to 10 parts by mass, more preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the total amount of energy ray polymerizable compounds 0.3 to 5 parts by mass. (other additives)

The composition for buffer layer formation may contain other additives in the range which does not impair the effect of this invention. Examples of other additives include antistatic agents, antioxidants, softeners (plasticizers), fillers, antirust agents, pigments, dyes, and the like. When these additives are prepared, the content of each additive in the composition for forming a buffer layer 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 the energy ray polymerizable compound. (resin component)

The composition for buffer layer formation may contain a resin component in the range which does not impair the effect of this invention. Examples of the resin component include polyene-thiol-based resins and the like; polyolefin-based resins such as polybutene, polybutadiene, and polymethylpentene; and thermoplastic resins such as styrene-based copolymers. The content of these resin components in the composition for forming a buffer layer is preferably 0 to 20 parts by mass, more preferably 0 to 10 parts by mass, more preferably 0 to 5 parts by mass, particularly preferably 0 to 2 parts by mass.

The buffer layer formed from the composition for forming a buffer layer containing an energy ray polymerizable compound is obtained by irradiating the composition for forming a buffer layer having the above-mentioned composition with energy rays, and polymerizing and hardening the composition for forming a buffer layer. That is, this buffer layer is a cured product of the composition for buffer layer formation. Thus, this buffer layer comprises polymeric units derived from component (a1). Also, this buffer layer preferably contains polymerized units derived from component (a2) and/or polymerized units derived from component (a3); it may also contain polymerized units derived from component (a4) and/or polymerized units derived from component (a5) aggregation unit. The content rate of each polymer unit in a buffer layer is usually the same as the ratio (addition ratio) of each component which comprises the composition for buffer layer formation. For example, when the content of component (a1) in the composition for buffer layer formation is 10 to 70 parts by mass relative to the total amount (100 parts by mass) of the composition for buffer layer formation, the buffer layer contains 10 to 70 parts by mass of component (a1 ) derived polymeric units. Moreover, when the content of the component (a2) in the composition for forming a buffer layer is 10 to 80 parts by mass relative to the total amount (100 parts by mass) of the composition for forming a buffer layer, the buffer layer contains 10 to 80 parts by mass of the component ( a2) Derived polymeric units. The same applies to components (a3)~(a5). <Layer containing polyolefin resin film>

The buffer layer can be formed by a layer including a polyolefin resin film.

When the buffer layer is a layer containing a polyolefin resin film, the stress relaxation property may be lower than when the buffer layer is a layer formed of a buffer layer-forming composition containing an energy ray polymerizable compound. In this case, the pressure-sensitive adhesive tape having a buffer layer formed of a layer including a polyolefin resin film on one side of the substrate may be warped. Although the buffer layer formed by the layer containing the polyolefin resin film may be provided on at least one side of the substrate, but from the viewpoint of preventing such defects, the buffer layer formed by the layer containing the polyolefin resin film It is better to install on both sides of the substrate.

The polyolefin resin is not particularly limited, and examples thereof include ultra-low-density polyethylene (VLDPE, density: 880 kg/m ³ to less than 910 kg/m ³ ), low-density polyethylene (LDPE, density: 910 kg/m ³ to less than 930kg/m ³ ), medium-density polyethylene (MDPE, density: 930kg/m ³ or more and less than 942kg/m ³ ), high-density polyethylene (HDPE, density: 942kg/m ³ or more) and other polyethylene resins, polyester Acrylic resin, polyethylene-polypropylene copolymer, olefin-based elastomer (TPO), cycloolefin resin, ethylene-vinyl acetate copolymer (EVA), ethylene-vinyl acetate-maleic anhydride copolymer, ethylene- (Meth)acrylic acid copolymer, ethylene-(meth)acrylate copolymer, ethylene-(meth)acrylate-maleic anhydride copolymer, etc. These polyolefin resins can be used individually or in combination of 2 or more types.

Among the above-mentioned polyolefin resins, polyethylene resins are preferred, and low-density polyethylene is preferred from the viewpoint of obtaining a buffer layer having specific physical properties.

The buffer layer may contain plasticizers, lubricants, infrared absorbers, ultraviolet absorbers, fillers, colorants, antistatic agents, antioxidants, catalysts, etc. within the range that does not impair the effects of the present invention. additives. In addition, the above-mentioned buffer layer may be transparent or opaque, and may be colored or vapor-deposited as necessary. 〇Peeling sheet

The release sheet can also be pasted on the surface of the adhesive tape. Specifically, the release sheet is attached to the surface of the adhesive layer of the adhesive tape. The release sheet protects the adhesive layer during transportation and storage by sticking to the surface of the adhesive layer. The release sheet is attached to the adhesive tape in a detachable manner, and is peeled off and removed from the adhesive tape before the adhesive tape is used (that is, before the wafer is attached). As the release sheet, at least one side thereof is subjected to a release treatment, and specifically, one in which a release agent is applied to the surface of a base material for a release sheet is used.

As the base material for the release sheet, a resin film is preferred, and as the resin constituting the resin film, for example, polyethylene terephthalate resin, polybutylene terephthalate resin, polyethylene naphthalate resin, etc. Polyester resin films such as diester resins, polyolefin resins such as polypropylene resins and polyethylene resins, and the like. Examples of release agents include rubber-based elastomers such as silicone-based resins, olefin-based resins, isoprene-based resins, and butadiene-based resins, long-chain alkyl-based resins, alkyd-based resins, fluorine-based Department of resin, etc. The thickness of the release sheet is not particularly limited, preferably 10-200 μm, more preferably 20-150 μm. 〇Adhesive tape manufacturing method

It does not specifically limit as a manufacturing method of the adhesive tape of this invention, It can manufacture by a well-known method. For example, the manufacturing method of the adhesive tape which has a base material, the adhesive layer provided on one side of this base material, and the cushion layer provided on the other side of this base material is as follows.

When the cushion layer is formed of a composition for forming a cushion layer containing an energy ray polymerizable compound, the cushion layer formed by applying the composition for forming a cushion layer on a release sheet and curing it can be bonded to a substrate and The release sheet was removed to obtain a laminate of the buffer layer and the substrate. Moreover, when a buffer layer is a layer containing a polyolefin resin film, a buffer layer and a base material are bonded together, and the laminated body of a buffer layer and a base material is obtained.

Then, the adhesive layer provided on the release sheet is bonded to the base material side of the laminate to manufacture an adhesive tape in which the release sheet is attached to the surface of the adhesive layer. The release sheet attached to the surface of the adhesive layer may be properly peeled off and removed before use of the adhesive tape.

As a method of forming the adhesive layer on the release sheet, the adhesive (adhesive composition) can be directly coated on the release sheet by a known coating method, and the coated film is heated and dried to form the adhesive layer.

In addition, an adhesive (adhesive composition) may be directly applied to one surface of a substrate to form an adhesive layer. As the application method of the adhesive, spray coating method, bar coating method, blade coating method, roll coating method, blade coating method, die coating method, gravure coating method disclosed in the production method of buffer layer, etc. coating method, etc.

As a method of forming the buffer layer on the release sheet, a coating film can be formed by directly coating the composition for buffer layer formation on the release sheet using a known coating method, and irradiating the coating film with energy rays. The buffer layer. In addition, the buffer layer-forming composition may be directly coated on one surface of the substrate, and the buffer layer may be formed by heating and drying or irradiating the coating film with energy rays.

Examples of coating methods of the buffer layer forming composition include spin coating, spray coating, bar coating, knife coating, roll coating, blade coating, and die coating. , gravure coating method, etc. Moreover, in order to improve applicability, an organic solvent may be mix|blended with the composition for buffer layer formation, and you may apply|coat on a peeling sheet in the form of a solution.

When the composition for buffer layer formation contains an energy ray polymerizable compound, it is preferable to form a buffer layer by irradiating the coating film of the composition for buffer layer formation with energy rays and hardening it. The hardening of the buffer layer may be performed in one hardening treatment, or may be divided into plural times and performed. For example, the coating film on the release sheet can be completely hardened to form a buffer layer and then attached to the substrate, or the coating film can be incompletely cured to form a semi-cured buffer layer forming film, and this buffer layer can be formed into a film After bonding to the base material, it is irradiated with energy rays again to harden completely to form a buffer layer. Ultraviolet rays are preferable as the energy rays irradiated for this hardening treatment. In addition, although the coating film of the buffer layer-forming composition may be exposed at the time of curing, the energy is irradiated in a state where the coating film is covered with a release sheet, a base material, etc., and the coating film is not exposed. It is better to harden the thread.

When the cushioning layer is a layer containing a polyolefin resin film, the cushioning layer and the base material may be bonded together by extrusion lamination. Specifically, the polyolefin resin constituting the buffer layer is melted/kneaded using a T-die film maker, etc., and the melted polyolefin resin is extrusion-laminated on one side of the substrate while moving the substrate at a constant speed. side. In addition, the buffer layer may be directly laminated on the base material by heat sealing or the like. In addition, it is also possible to laminate via an easy-adhesive layer using methods such as a dry lamination method.

In addition, the production method of the adhesive tape in which the buffer layer is provided on both sides of the base material, for example, using the above-mentioned method, obtains a laminate in which the buffer layer, the base material, and the buffer layer are sequentially laminated, and then forms the adhesive layer on the One side of the buffer side will do. 〇Semiconductor device manufacturing method

The adhesive tape related to the present invention is preferably used when it is attached to the front surface of a semiconductor wafer and the back surface of the wafer is ground. The adhesive tape related to the present invention is preferably a DBG that can be used suitably for grinding the backside of the wafer and individualizing the wafer at the same time. The adhesive tape related to the present invention is particularly preferably LDBG which can be used suitably to obtain a wafer group with a small kerf width when individualizing semiconductor wafers. Also, the so-called "chip group" refers to a plurality of semiconductor chips arranged in a wafer shape that are fixed on the adhesive tape of the present invention. As a non-limiting usage example of the adhesive tape, a method of manufacturing a semiconductor device will be described more specifically below.

The method of manufacturing a semiconductor device specifically includes at least the following steps 1 to 4. Step 1: a step of attaching the above-mentioned adhesive tape to the front surface of the semiconductor wafer, and cutting the adhesive tape along the periphery of the semiconductor wafer; Step 2: forming a trench from the front side of the semiconductor wafer, or forming a modified region inside the semiconductor wafer from the front or back side of the semiconductor wafer; Step 3: Grinding the semiconductor wafer with the above-mentioned grooves or modified regions formed on the front surface with the adhesive tape attached, grinding from the back side, and individualizing the semiconductor wafers into a plurality of wafers starting from the grooves or modified regions; Step 4: Peel off the adhesive tape from the individualized semiconductor wafer (that is, a plurality of semiconductor wafers).

Hereinafter, each step of the manufacturing method of the above-mentioned semiconductor device will be described in detail. (step 1) In step 1, the adhesive tape of the present invention is attached to the front surface of the semiconductor wafer through the adhesive layer, and cut along the outer periphery of the semiconductor wafer. The adhesive tape is attached in such a way as to cover the semiconductor wafer and the peripheral machine extending its outer periphery. Then, the adhesive tape is cut along the outer periphery of the semiconductor wafer by a cutter or the like. The cutting speed is usually 10~300mm/s. The temperature of the blade of the cutter during cutting can be room temperature, and the blade of the cutter can also be heated before cutting.

This step can be performed before step 2 described later, or after step 2. For example, in the case of forming a modified region on a semiconductor wafer, it is preferable to perform step 1 before step 2. On the other hand, when trenches are formed by dicing or the like on the front surface of the semiconductor wafer, step 1 is performed after step 2 . That is, through this step 1, the adhesive tape is attached to the front surface of the wafer having the grooves formed in step 2 described later.

The semiconductor wafer used in this manufacturing method may be a silicon wafer, or a wafer of gallium arsenide, silicon carbide, lithium tantalate, lithium niobate, gallium nitride, indium phosphorus, or a glass wafer. The thickness of the semiconductor wafer before grinding is not particularly limited, but is usually about 500 to 1000 μm. Also, a semiconductor wafer usually has circuits formed on its front side. Forming the circuit on the front side of the wafer can be carried out by various methods including conventional general methods such as etching method and lift-off method. (step 2)

In Step 2, a trench is formed from the front side of the semiconductor wafer, or a modified region is formed inside the semiconductor wafer from the front or back side of the semiconductor wafer. The trenches formed in this step are shallower than the thickness of the semiconductor wafer. The trenches can be formed by dicing using a known wafer dicing device or the like. In addition, the semiconductor wafer is divided into a plurality of semiconductor wafers along the grooves in step 3 described later.

In addition, the modified region is an embrittled part of the semiconductor wafer, and the semiconductor wafer is thinned by grinding in the grinding step, and the semiconductor wafer is broken and individualized by the force applied by grinding, etc. The area where the semiconductor wafer starts. That is, in Step 2, trenches and modified regions are formed along the dividing lines when dividing the semiconductor wafer into individual semiconductor wafers in Step 3 to be described later.

The modified region is formed by irradiating a laser focused on the inside of the semiconductor wafer, and the modified region is formed inside the semiconductor wafer. Laser irradiation may be performed from the front side of the semiconductor wafer or may be performed from the back side. In addition, in the aspect of forming the modified region, when step 2 is performed after step 1 and laser irradiation is performed from the front surface of the wafer, the semiconductor wafer is irradiated with laser light through the adhesive tape. The semiconductor wafer attached with the adhesive tape and formed with grooves or modified regions is placed on the chuck seat, and is absorbed and stabilized by the chuck seat. At this time, the semiconductor wafer is adsorbed by being arranged on the machine side on the front side. (step 3)

After Step 1 and Step 2, the back surface of the semiconductor wafer on the chuck seat is ground to separate the semiconductor wafer into a plurality of semiconductor wafers. Here, the back grinding is performed so that the semiconductor wafer is thinned to at least reach the bottom of the trench when the trench is formed on the semiconductor wafer. With this backside grinding, the trench becomes a slit that penetrates the wafer, and the semiconductor wafer is divided by the slit to be individually sliced into individual semiconductor chips.

On the other hand, when a modified region is formed, the polished surface (wafer back surface) may reach the modified region by grinding, or may not reach the modified region precisely. That is, the semiconductor wafer may be broken and individually sliced into semiconductor wafers by polishing to a position close to the modified region, starting from the modified region. For example, actual individualization of semiconductor wafers may be carried out by extending the pick-up tape after attaching the pick-up tape described later.

In addition, after the back grinding is completed, dry polishing may be performed before picking up the wafer.

The shape of the individualized semiconductor wafers may be rectangular or elongated, such as a rectangle. Also, the thickness of the individualized semiconductor wafer is not particularly limited, but is preferably about 5 to 100 μm, more preferably 10 to 45 μm. In the case of LDBG in which a modified region is provided inside the wafer by laser, and the wafer is individually sliced by stress during wafer backgrinding, etc., the thickness of the individualized semiconductor wafer can be easily reduced to 50 μm or less. Preferably it is 10-45 μm. Also, the size of the individualized semiconductor wafers is not particularly limited, and the wafer size is preferably less than 600mm ² , more preferably less than 400mm ² , more preferably less than 300mm ² .

If the adhesive tape of the present invention is used, even such a thin and/or small semiconductor wafer can prevent cracks from being generated on the semiconductor wafer when the adhesive tape is peeled off (step 4) as follows. (step 4)

The adhesive tape is peeled off from the individualized semiconductor wafer (that is, a plurality of semiconductor wafers arranged in a wafer shape). This step is performed, for example, by the following method. First, when the adhesive layer of the adhesive tape is formed of an energy ray-curable adhesive, energy rays are irradiated to harden the adhesive layer. Next, a pick-up tape is attached to the back side of the individualized semiconductor wafer, and the position and direction are aligned to enable pick-up. At this time, a ring frame (ring frame) disposed on the outer peripheral side of the wafer is also attached to the pick tape, and the outer peripheral edge portion of the pick tape is fixed to the ring frame. The pickup tape can be attached to the wafer and the ring frame at the same time, or it can be attached according to the respective timing. Next, the plurality of semiconductor wafers held on the pick-up tape are peeled off from the adhesive tape.

Subsequently, a plurality of semiconductor wafers located on the pick-up tape are picked up and fixed on a substrate etc. to manufacture a semiconductor device. Moreover, the pick-up tape is not specifically limited, For example, it can be comprised with the adhesive tape provided with the base material and the adhesive agent layer provided in the surface of at least one side of the base material.

Also, an adhesive tape may be used instead of the pick-up tape. The adhesive tape includes a laminate of a film adhesive and a release sheet, a laminate of a dicing tape and a film adhesive, an adhesive layer and a release sheet having both the functions of a dicing tape and a die bonding tape. The formed dicing/die bonding tape, etc. That is, in this embodiment, the process of affixing a dicing/die-bonding tape to the back surface of a semiconductor wafer may also be included. Moreover, before attaching a pick-up tape, a film-form adhesive agent may be bonded to the back side of the individualized semiconductor wafer. In the case of using a film adhesive, the film adhesive may have the same shape as the wafer.

Here, when the adhesive layer of the adhesive tape is formed of an energy ray-curable adhesive, when the energy ray is irradiated, the portion of the adhesive layer in close contact with the wafer is cured, and the adhesive force of the portion is sufficiently reduced. However, in the portion of the adhesive tape that is not in close contact with the wafer and is exposed to the atmosphere, the hardening of the adhesive is usually hindered by the oxygen in the atmosphere, and the adhesive force is not sufficiently reduced even if it is not hardened by irradiation of energy rays such as ultraviolet rays. . Therefore, as shown in FIG. 3, in the case where the thickness of the semiconductor wafer has been extremely thinned to about 30 μm by backside grinding, once the dicing/die bonding tape is attached to the backside of the semiconductor wafer, it is attached to The uncured portion of the adhesive layer of the adhesive tape on the front surface of the semiconductor wafer is in contact with and attached to the adhesive layer of the dicing/die bonding tape or the like. Then, once the adhesive tape attached to the dicing/die bonding tape etc. is to be peeled off, the adhesive tape and the dicing/die bonding tape are integrated, and the dicing/die bonding tape will also bend along with the bending of the adhesive tape, Then, the wafer, wafer, etc. sandwiched between the adhesive tape and the dicing/die bonding tape are also flexed simultaneously. As a result, cracks tend to occur on the wafer. In addition, adhesive layers such as dicing/die-bonding tapes are damaged by bending, and fragments thereof may fall off.

On the other hand, according to the adhesive tape according to this embodiment, it is possible to prevent cracks from being generated on the semiconductor wafer when the adhesive tape is peeled off. FIG. 5 is a schematic diagram of a laminate in which a dicing/die-bonding tape 30 is further attached to a semiconductor wafer 20 after back grinding to which the adhesive tape according to this embodiment has been attached. FIG. 5 shows a state where a dicing/die bonding tape 30 is attached to a semiconductor wafer 20 whose back surface has been ground to an extremely thin thickness of about 30 μm. In the adhesive tape according to this embodiment, even if the adhesive layer is exposed to the air atmosphere, the adhesive force can be sufficiently reduced by irradiation of energy rays. Therefore, as shown in FIG. 5, when the thickness of the semiconductor wafer is extremely thinned to about 30 μm by backside grinding, even if a part of the adhesive layer of the adhesive tape attached to the front surface of the semiconductor wafer and the dicing / Adhesive layers such as die bonding tape are in contact with each other, and the two are not attached. Therefore, the adhesive tape is not integrated with the dicing/die bonding tape and can be peeled off. As a result, cracking of the wafer can be suppressed.

When using an adhesive tape, when attaching a film-like adhesive to the back side of an individualized semiconductor wafer before attaching a pick-up tape, etc., multiple semiconductor wafers on the adhesive tape, pick-up tape, etc. are The semiconductor wafer is picked up together with the adhesive layer divided into the same shape. Then, the semiconductor wafer is fixed on a substrate or the like through an adhesive layer to manufacture a semiconductor device. The division of the adhesive layer is carried out by laser, expansion and the like.

In the above, the adhesive tape related to the present invention has been described as an example of the method of using DBG or LDBG to separate semiconductor wafers into pieces, but the adhesive tape related to the present invention can also be suitably used for separating semiconductor wafers. LDBG with smaller kerf width and thinner wafer group can be obtained when circular singulation is performed. In addition, the adhesive tape related to the present invention can also be used for normal back grinding, and can also be used for temporarily stabilizing a workpiece during processing of glass, ceramics, and the like. Furthermore, it can also be used as various re-peelable adhesive tapes. [Example]

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited by these examples.

The measurement method and evaluation method are as follows. The results are shown in Table 1. [Surface modulus]

For adhesive tapes for semiconductor processing, with one side of the adhesive layer exposed to the atmosphere, an ultraviolet irradiation device (manufactured by Lintec Corporation, device name "RAD 2000") was used, with an illuminance of 220mW/cm ² and a light intensity of 500mJ/cm ² Under the condition of irradiating ultraviolet rays to the adhesive tape from the base material side. A silicon nitride cantilever (manufactured by Bruker Corporation, "SCANASYST-AIR") installed on an atomic force microscope (manufactured by Bruker Corporation, device name "Dimension Icon"), nominal tip radius: 2nm, resonance frequency: 70kHz, spring constant: 0.4N/m), the surface of the adhesive layer was indented and separated at room temperature with an indentation amount of 5nm and a scan rate of 5Hz. For the obtained force curve (the horizontal axis is the amount of deformation of the sample, and the vertical axis is the measured load), it is fitted with the JKR theoretical formula to calculate the surface elastic modulus. The average value of the values measured at 4096 points in the surface 5 μm×5 μm of the adhesive layer was defined as the surface modulus (MPa). [Peel off evaluation]

Using a tape laminator for back grinding (manufactured by LINTEC, device name "RAD-3510F/12"), an adhesive tape is attached to a silicon wafer with a diameter of 12 inches and a thickness of 775 μm, along the outer circumference of the silicon wafer. judge. For the silicon wafer, use a laser cutting machine (manufactured by DISCO, device name "DFL7361") to irradiate laser light with a wavelength of 1342nm from the front surface of the silicon wafer, and cut the inside of the silicon wafer with a wafer size of 5mm x 5mm. A modified region is formed. Next, using a grinder (manufactured by DISCO, device name "DGP8760"), the back surface of the silicon wafer was ground to a thickness of 30 μm after grinding. At this time, the size of the adhesive tape is such that it covers the outer periphery of the ground silicon wafer and is 1.0 mm larger than the outer edge of the silicon wafer. Using an ultraviolet irradiation device (manufactured by Lintec Corporation, device name "RAD 2000"), the adhesive tape was irradiated with ultraviolet light from the substrate side, that is, the front side of the silicon wafer, under the conditions of an illuminance of 220 mW/cm ² and a light intensity of 500 mJ/cm ² . Using a tape mounter (manufactured by LINTEC Corporation, device name "ADWILL RAD-2700"), while heating the adhesive surface of the dicing/die bonding tape (manufactured by LINTEC Corporation, LD01D-07) to 60°C, Attached to the back of the silicon wafer. Peel off the adhesive tape. The degree of peeling of the adhesive layer of the dicing/die-bonding tape at this time was observed and evaluated by the following reference|standard. A: The peeled area is less than 70%. B: The peeled area is 70% or more and less than 97%. C: The peeled area is 97% or more. [Surface Free Energy]

For adhesive tapes for semiconductor processing, with one side of the adhesive layer exposed to the atmosphere, an ultraviolet irradiation device (manufactured by Lintec Corporation, device name "RAD 2000") was used, with an illuminance of 220mW/cm ² and a light intensity of 500mJ/cm ² Under the condition of irradiating ultraviolet rays to the adhesive tape from the base material side. Using a contact angle meter (manufactured by Kyowa Interface Science Co., Ltd., device name "DM-70"), using diiodomethane, 1-bromonaphthalene, and distilled water as droplets, by the static drop method, according to JIS R 3257: 1999 was used to measure the contact angle (measurement temperature: 25°C), and based on the value of the contact angle, the surface free energy (mJ/m ² ) was calculated by the Kitazaki・Hata method. [Peel strength]

For an adhesive tape for semiconductor processing (width 25 mm) composed of a base material and an adhesive layer, an ultraviolet irradiation device (manufactured by Lintec Corporation, device name "RAD 2000") was used with the adhesive layer exposed to the atmosphere. ), irradiate the adhesive tape with ultraviolet light from the substrate side under the conditions of illuminance 220mW/cm ² and light intensity 500mJ/cm ² . A PMMA plate ("ACRYLITE L001" manufactured by Mitsubishi Chemical Corporation with a thickness of 2 mm, a width of 70 mm, and a length of 150 mm) was attached to the exposed surface of the adhesive layer with a 2 kg roller at 23°C and 50% RH, and left After 30 minutes, the peel strength when this adhesive tape was peeled at 180° was measured under conditions of a measurement temperature of 25° C. and a peel speed of 300 mm/min. It was measured twice under the same conditions, and the average values are shown in Table 1. [adhesion energy]

For adhesive tapes for semiconductor processing, with one side of the adhesive layer exposed to the atmosphere, an ultraviolet irradiation device (manufactured by Lintec Corporation, device name "RAD 2000") was used, with an illuminance of 220mW/cm ² and a light intensity of 500mJ/cm ² Under the condition of irradiating ultraviolet rays to the adhesive tape from the base material side. A silicon nitride cantilever (manufactured by Bruker Corporation, "SCANASYST-AIR") installed on an atomic force microscope (manufactured by Bruker Corporation, device name "Dimension Icon"), nominal tip radius: 2nm, resonance frequency: 70kHz, spring constant: 0.4N/m), the surface of the adhesive layer was indented and separated at room temperature with an indentation amount of 5nm and a scan rate of 5Hz. For the obtained force curve (the horizontal axis is the deformation of the sample, and the vertical axis is the measured load), fit it with the JKR theoretical formula to calculate the adhesion energy. The average value of the values measured at 4096 points on the surface of the adhesive layer of 5 μm×5 μm was defined as the adhesive energy (J/m ² ).

All parts by mass of the following examples and comparative examples are converted into solid content. <Example 1> (1) Substrate

As a base material, a PET film (Cosmoshine A4300 manufactured by Toyobo Co., Ltd., thickness: 50 μm, Younger modulus at 23° C.: 2550 MPa) with easy-adhesive layers on both sides was prepared. (2) Adhesive layer (Preparation of Adhesive Composition)

An acrylic polymer obtained by copolymerizing 50 parts by mass of n-butyl acrylate (BA), 20 parts by mass of methyl methacrylate (MMA), and 30 parts by mass of 2-hydroxyethyl methacrylate (HEMA), Energy ray-curable acrylic resin is obtained by reacting with 2-methacryloxyethyl isocyanate (MOI) in such a way that 90 mol% of the hydroxyl groups are added to the total hydroxyl groups of the acrylic polymer .

With respect to 100 parts by mass of the total amount of this energy ray-curable acrylic resin, 12 parts by mass of polyfunctional urethane acrylate as an energy ray-curable compound, and an isocyanate-based crosslinking agent (manufactured by TOSOH, product name "CORONATE L") were mixed. ) 1.1 parts by mass, 3.3 parts by mass of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (manufactured by IGM Resins B.V., product name "OMNIRAD TPO") as a photopolymerization initiator, Furthermore, it diluted with methyl ethyl ketone, and prepared the coating liquid of the adhesive composition with a solid content concentration of 32 mass %. (3) Manufacture of adhesive tape

The coating solution of the adhesive composition obtained above was applied to the release-treated surface of a release sheet (manufactured by Lintec Corporation, trade name "SP-PET381031"), and dried by heating to form a 30-μm-thick film on the release sheet. Adhesive layer. The surface of the formed adhesive layer is bonded to the substrate to manufacture an adhesive tape for semiconductor processing. <Example 2>

In the preparation of the adhesive composition, in addition to adding 50 parts by mass of n-butyl acrylate (BA), 20 parts by mass of methyl methacrylate (MMA), 15 parts by mass of 2-hydroxy acrylate (HEA) and 2- An adhesive tape for semiconductor processing was produced in the same manner as in Example 1 except that 15 parts by mass of hydroxyethyl ester (HEMA) was copolymerized to obtain an acrylic polymer. <Example 3>

In preparing the adhesive composition, in addition to copolymerizing 60 parts by mass of ethyl acrylate (EA), 10 parts by mass of methyl methacrylate (MMA), and 30 parts by mass of 2-hydroxyethyl methacrylate (HEMA), To obtain an acrylic polymer, use 2.4 parts by mass of 2,2-dimethoxy-2-phenylacetophenone (manufactured by IGM Resins B.V., product name "OMNIRAD 651") to replace bis(2,4,6-tris An adhesive tape for semiconductor processing was produced in the same manner as in Example 1 except that 3.3 parts by mass of methylbenzoyl)phenylphosphine oxide was used as a photopolymerization initiator. <Example 4>

In the preparation of the adhesive composition, in addition to copolymerizing 60 parts by mass of n-butyl acrylate (BA), 10 parts by mass of methyl methacrylate (MMA), and 30 parts by mass of 2-hydroxyethyl methacrylate (HEMA) To obtain an acrylic polymer, 2.4 parts by mass of 2,2-dimethoxy-2-phenylacetophenone (manufactured by IGM Resins B.V., product name "OMNIRAD 651") was used to replace bis(2,4,6- Except having used 3.3 parts by mass of trimethylbenzoyl)phenylphosphine oxide as a photoinitiator, it carried out similarly to Example 1, and produced the adhesive tape for semiconductor processing. <Example 5>

In the preparation of the adhesive composition, in addition to copolymerizing 65 parts by mass of n-butyl acrylate (BA), 5 parts by mass of methyl methacrylate (MMA), and 30 parts by mass of 2-hydroxyethyl methacrylate (HEMA) To obtain an acrylic polymer, 2.4 parts by mass of 2,2-dimethoxy-2-phenylacetophenone (manufactured by IGM Resins B.V., product name "OMNIRAD 651") was used to replace bis(2,4,6- Except having used 3.3 parts by mass of trimethylbenzoyl)phenylphosphine oxide as a photoinitiator, it carried out similarly to Example 1, and produced the adhesive tape for semiconductor processing. <Example 6>

In the preparation of the adhesive composition, in addition to adding 60 parts by mass of 2-ethylhexyl acrylate (2EHA), 10 parts by mass of methyl methacrylate (MMA), and 30 parts by mass of 2-hydroxyethyl methacrylate (HEMA) 2.4 parts by mass of substituted bis(2,4 , Except having used 3.3 parts by mass of 6-trimethylbenzoyl)phenylphosphine oxide as a photoinitiator, it carried out similarly to Example 1, and manufactured the adhesive tape for semiconductor processing. <Example 7>

In the preparation of the adhesive composition, in addition to adding 40 parts by mass of 2-ethylhexyl acrylate (2EHA), 20 parts by mass of ethyl acrylate (EA), 10 parts by mass of methyl methacrylate (MMA), and methacrylic acid Acrylic polymer was obtained by copolymerizing 30 parts by mass of 2-hydroxyethyl ester (HEMA), using 2,2-dimethoxy-2-phenylacetophenone (manufactured by IGM Resins B.V., product name "OMNIRAD 651") ) 2.4 parts by mass instead of 3.3 parts by mass of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, as a photopolymerization initiator, an adhesive tape for semiconductor processing was produced in the same manner as in Example 1. <Example 8>

In the preparation of the adhesive composition, in addition to 60 parts by mass of ethyl acrylate (EA), 10 parts by mass of methyl methacrylate (MMA), 15 parts by mass of 2-hydroxy acrylate (HEA), and 2-hydroxy methacrylate Acrylic polymer obtained by copolymerizing 15 parts by mass of ethyl ester (HEMA), using 2,2-dimethoxy-2-phenylacetophenone (manufactured by IGM Resins B.V., product name "OMNIRAD 651") 2.4 mass An adhesive tape for semiconductor processing was produced in the same manner as in Example 1, except that 3.3 parts by mass of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide was substituted as a photopolymerization initiator. <Example 9>

In the preparation of the adhesive composition, in addition to adding 60 parts by mass of n-butyl acrylate (BA), 10 parts by mass of methyl methacrylate (MMA), 15 parts by mass of 2-hydroxy acrylate (HEA), and 2 Acrylic polymer obtained by copolymerizing 15 parts by mass of -hydroxyethyl ester (HEMA), using 2,2-dimethoxy-2-phenylacetophenone (manufactured by IGM Resins B.V., product name "OMNIRAD 651") An adhesive tape for semiconductor processing was produced in the same manner as in Example 1, except that 2.4 parts by mass was substituted for 3.3 parts by mass of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide as a photopolymerization initiator. <Example 10>

In the preparation of the adhesive composition, in addition to 52 parts by mass of n-butyl acrylate (BA), 20 parts by mass of methyl methacrylate (MMA), 21 parts by mass of 2-hydroxy acrylate (HEA), and methacrylic acid An adhesive tape for semiconductor processing was produced in the same manner as in Example 1 except that 7 parts by mass of 2-hydroxyethyl ester (HEMA) was copolymerized to obtain an acrylic polymer. ＜Comparative example 1＞

In the preparation of the adhesive composition, in addition to copolymerizing 52 parts by mass of n-butyl acrylate (BA), 20 parts by mass of methyl methacrylate (MMA), and 28 parts by mass of 2-hydroxy acrylate (HEA) to obtain acrylic acid The adhesive tape for semiconductor processing was produced similarly to Example 1 except that it was a polymer.

[Table 1] Composition of the adhesive composition (parts by mass) Surface elastic modulus [MPa] Surface free energy [mJ/m ² ] Peel strength [mN/25mm] Adhesive energy[J/m ² ] Strip evaluation BA 2EHA EA MMA HEA HEMA Example 1 50 20 30 13.3 27.6 84 0.170 A Example 2 50 20 15 15 7.2 30.9 168 0.164 A Example 3 60 10 30 15.0 30.3 380 0.150 A Example 4 60 10 30 10.0 28.7 410 0.183 A Example 5 65 5 30 9.0 27.5 485 0.178 A Example 6 60 10 30 7.5 22.4 500 0.185 A Example 7 40 20 10 30 8.5 24.0 500 0.170 A Example 8 60 10 15 15 12.9 31.0 620 0.166 A Example 9 60 10 15 15 6.9 31.5 960 0.186 A Example 10 52 20 twenty one 7 6.0 33.6 1000 0.180 B Comparative example 1 52 20 28 4.9 36.9 1675 0.233 C

From the above results, it was found that the adhesive tape for semiconductor processing according to the present invention can reduce the surface elastic modulus of the adhesive layer and sufficiently reduce the adhesive force even in the atmosphere by irradiation of energy rays such as ultraviolet rays. Therefore, under the use of the adhesive tape related to the present invention, even if the thickness of the semiconductor wafer is extremely thinned by back grinding, cracking of the semiconductor wafer can still be suppressed and the productivity of the semiconductor device can be improved.

10: Adhesive tape 20: Semiconductor wafer (wafer) 30: Dicing/Die Bonding Tape 100: Adhesive tape 110: Substrate 120: Adhesive layer

FIG. 1 is a schematic diagram showing the process of backside grinding of a semiconductor wafer. FIG. 2 is a schematic diagram of a laminate composed of an adhesive tape 10, a semiconductor wafer 20 after backside grinding, and a dicing/die bonding tape 30, showing that the thickness of the semiconductor wafer 20 is greater than that of FIG. 3. Fig. 3 is a schematic diagram of a laminate composed of an adhesive tape 10, a backside-ground semiconductor wafer 20, and a dicing/die-bonding tape 30, showing a state in which the backside of the semiconductor wafer 20 is ground and the thickness is extremely thinned to about 30 μm. . Fig. 4 is a schematic diagram showing the adhesive tape related to this embodiment. Fig. 5 is a schematic diagram of a laminate composed of the adhesive tape according to the present embodiment, the semiconductor wafer 20 after back grinding, and the dicing/die bonding tape 30, showing that the thickness of the semiconductor wafer 20 is extremely thinned to 30 μm by grinding the back side of the semiconductor wafer 20 left and right situations.

100: Adhesive tape

110: Substrate

120: Adhesive layer

Claims (5)

An adhesive tape for semiconductor processing, which is an adhesive tape having a base material and an adhesive layer, wherein one side of the adhesive layer is exposed to the air atmosphere, and the illuminance is 220mW/ ^cm2 and the light intensity is 500mJ/ ^cm2 . The surface elastic modulus of the exposed surface of the adhesive layer after the adhesive tape is irradiated with ultraviolet rays is 5 MPa or more. The adhesive tape for semiconductor processing according to claim 1, wherein the adhesive layer contains an acrylic resin, The content of the HEMA-derived polymerized units is 6 parts by mass or more relative to 100 parts by mass of the total amount of the acrylic resin. The adhesive tape for semiconductor processing according to claim 1 or 2, wherein the adhesive tape is irradiated with ultraviolet rays under conditions of illuminance 220 mW/cm ² and light intensity 500 mJ/cm ² in a state where one side of the adhesive layer is exposed to the atmosphere After that, the surface free energy of the exposed surface of the adhesive layer was less than 36 mJ/m ² . A method for manufacturing a semiconductor device, comprising the following steps: Attach the adhesive tape for semiconductor processing described in any one of Claims 1 to 3 on the front surface of the semiconductor wafer, and cut the adhesive tape along the periphery of the semiconductor wafer; Forming trenches from the front side of the aforementioned semiconductor wafer, or forming a modified region inside the semiconductor wafer from the front or back side of the aforementioned semiconductor wafer; Grinding the semiconductor wafer with the aforementioned adhesive tape on the front surface and forming the aforementioned groove or the aforementioned modified region, from the back side, and starting from the aforementioned groove or the aforementioned modified region, and individualizing it into a plurality of wafers; and The said adhesive tape was peeled off from the said some wafer. The method of manufacturing a semiconductor device as described in claim 4 further includes a step of attaching a dicing/die bonding tape to the back surface of the semiconductor wafer.

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