JP7069116B2 - Base material for back grind tape - Google Patents

Description

The present invention relates to a base material for an adhesive tape used for back grinding an adherend such as a semiconductor wafer, that is, a base material for a back grind tape.

Semiconductor wafers such as silicon and gallium arsenide are manufactured in a large diameter state. After forming a circuit on the front surface of a semiconductor wafer, it is ground to a predetermined thickness by back surface polishing, cut and separated (diced) into element small pieces (semiconductor chips), and then moved to the next step, a bonding step. ..

In the back surface grinding process, an adhesive tape called a back grind tape is used to hold the wafer during grinding and to protect the circuit surface from grinding debris and the like. Further, following the back surface grinding process, a circuit may be formed on the ground surface, and in this case as well, the wafer is protected and fixed with an adhesive tape for processing. The adhesive tape used for back surface processing such as back grind tape is composed of a base material and a pressure-sensitive adhesive layer. In particular, in order to reliably protect the circuit surface having irregularities on the surface, an adhesive tape using a relatively soft and highly stress relaxing base material may be used.

As an example of such an adhesive tape, Patent Document 1 (WO2013 / 141251A1) proposes a backgrinding tape having a pressure-sensitive adhesive layer on at least one side of a base material. Patent Document 1 discloses a substrate obtained by forming and curing an energy ray-curable composition containing a urethane acrylate-based oligomer, an energy ray-polymerizable monomer, and a polymerizable silicone compound.

During the back surface grinding process, the semiconductor wafer is fixed to the suction table via the back grind tape in the wafer back surface grinding apparatus. Then, after the back surface grinding step, the adhesive sheet 2 is attached to the ground surface of the wafer 1 as shown in FIGS. 1 and 2. The adhesive sheet 2 may be pre-cut according to the outer diameter of the ring frame 3, or may be cut according to the shape of the ring frame 3 after being attached. After the adhesive sheet 2 is attached, as shown in FIG. 3, the wafer 1 is lifted from the suction table 20 together with the back grind tape 10 by the transfer mechanism (convey arm 4) built in the wafer back surface grinding device, and is transferred to the next process. do. The backgrind tape 10 is composed of a base material 6 and an adhesive layer 5. The adhesive sheet has the functions of a single-layer film-like adhesive, a laminate of a film-like adhesive and a release sheet, a laminate of a dicing tape and a film-like adhesive, and both a dicing tape and a die-bonding tape. Examples thereof include a dicing / die bonding tape composed of an adhesive layer having an adhesive layer and a release sheet.

Since the adhesive sheet generally has a low tack at room temperature, the adhesive sheet is often attached while heating the semiconductor wafer. In such a step, the adhesive sheet is softened by heating to improve the adhesion between the adhesive sheet and the wafer. The heating to the wafer may be performed by heating the wafer attachment area on the adsorption table to 60 to 80 ° C. In addition, the heating time for the wafer may reach more than 30 minutes. Therefore, in such a step of heating the wafer, heat is propagated to the back grind tape (particularly the base material) in contact with the adsorption table, and the back grind tape (particularly the base material) is also heated. The base material of the backgrinding tape may be softened by heating and adhere to the suction table, and the wafer may not be lifted from the suction table even if a transport arm is used. Such process defects occur more prominently when the surface of the adsorption table has a porous structure. When such a process defect occurs, the wafer cannot be transferred to the next process, so that the production efficiency of the semiconductor device is lowered.

WO2013 / 141251A1

The present invention has been made in view of the above-mentioned prior art, and even if the semiconductor wafer is heated on the suction table when the adhesive sheet is attached to the semiconductor wafer after the back surface grinding step, the base material is the suction table. It is an object of the present invention to provide a substrate for a back grind tape which does not excessively adhere to a wafer and can be easily peeled off from a suction table.

The gist of the present invention for solving such a problem is as follows.
[1] A cured product of a substrate layer forming composition containing a urethane (meth) acrylate and a polymerizable compound having an energy ray-polymerizable group.
A substrate for backgrinding tape having a tensile storage elastic modulus of 8 MPa or more at 80 ° C.

[2] The substrate side of the laminate in which the PET film having a thickness of 75 μm, the pressure-sensitive adhesive layer having a thickness of 20 μm, and the substrate for backgrinding tape having a thickness of 50 μm are laminated is placed on an adsorption table heated to 80 ° C. After holding the adsorption at 85 kPa for 30 minutes, the adhesion between the substrate and the adsorption table when the laminate is peeled off at a peeling angle of 30 ° and a peeling speed of 300 mm / min with respect to the suction table is 1 N or less [1]. ] The base material for back grind tape described in.

[3] The base material for backgrinding tape according to [1] or [2], wherein the number of energy ray-polymerizable groups in the polymerizable compound having energy ray-polymerizable groups is 3 or more.

[4] The content according to any one of [1] to [3], wherein the content of the polymerizable compound having an energy ray-polymerizable group is 5 to 10% by mass with respect to the total amount of the composition for forming a substrate layer. Back grind tape base material.

[5] The backgrind according to any one of [1] to [4], wherein the composition for forming a substrate layer contains a heterocyclic group or a polymerizable compound having an alicyclic group having 6 to 20 ring-forming atoms. Base material for tape.

[6] The group for backgrinding tape according to [5], wherein the composition for forming a substrate layer contains two or more polymerizable compounds having the heterocyclic group or the alicyclic group having 6 to 20 ring-forming atoms. Material.

[7] An adhesive tape having an adhesive layer on at least one side of the substrate for backgrinding tape according to any one of [1] to [6] above.

The base material for backgrinding tape according to the present invention has heat resistance and is not easily deformed by heating. Therefore, even if the semiconductor wafer is heated on the suction table in the wafer back surface grinding device, the base material does not excessively adhere to the suction table, and the peelability from the suction table is excellent. As a result, the wafer can be conveyed without any trouble by the transfer mechanism built in the wafer back surface grinding device, and the production efficiency of the semiconductor device can be improved.

FIG. 1 is a schematic view showing a process of attaching an adhesive sheet to the ground surface of a wafer after the back surface grinding process. FIG. 2 is a schematic view showing a wafer transfer process. FIG. 3 is a schematic view showing a wafer transfer process. FIG. 4 is a perspective view showing a state in which a peeling tape is attached to the outer edge of the sample for measuring the adhesion force. FIG. 5 is a cross-sectional view taken along the line AA of FIG. FIG. 6 is a schematic diagram showing a method of measuring the adhesion force. FIG. 7 is a schematic diagram showing the peeling behavior at the interface between the back grind tape and the suction table.

Hereinafter, the present invention will be specifically described. First, the main terms used in the present specification will be described.
In the present specification, for example, "(meth) acrylate" is used as a term indicating both "acrylate" and "methacrylate", and the same applies to other similar terms.

The adhesive tape means a laminate including a base material and a pressure-sensitive adhesive layer provided on one surface side of the base material, and does not prevent the inclusion of other constituent layers other than these. For example, a primer layer may be formed on the surface of the base material on the pressure-sensitive adhesive layer side, and a release sheet for protecting the pressure-sensitive adhesive layer may be laminated on the surface of the pressure-sensitive adhesive layer until use. .. Further, the base material may be a single layer or a multilayer. The same applies to the pressure-sensitive adhesive layer.
The "front surface" of the semiconductor wafer refers to the surface on which the circuit is formed, and the "back surface" refers to the surface on which the circuit is not formed.

[Base material for back grind tape]
The base material for backgrinding tape according to the present invention is a cured product of a base material layer forming composition containing urethane (meth) acrylate (a1) and a polymerizable compound (a2) having an energy ray-polymerizable group. , The tensile storage elasticity (E'80) at ₈₀ ° C. is 8 MPa or more. In the following, the "base material for backgrinding tape" may be simply referred to as "base material".
When the semiconductor wafer is heated in the wafer back surface grinding apparatus, the adsorption table may be heated to about 60 to 80 ° C. to propagate the heat to the semiconductor wafer. Since the semiconductor wafer is placed on the suction table via the back grind tape, the back grind tape (particularly the base material) is easily affected by the heat of the suction table. When the tensile storage elastic modulus (E'80) of the substrate at 80 ° C. is less than ₈ MPa, when the adsorption table is heated to about 60 to 80 ° C., the substrate adheres to the adsorption table and backs from the adsorption table. The grind tape cannot be peeled off, and the transfer mechanism built into the device makes it difficult to transfer to the next process.

From this point of view, the tensile storage elastic modulus (E'80) of the substrate at ₈₀ ° C. is preferably 8 to 200 MPa, more preferably 9 to 30 MPa. The tensile storage elastic modulus (E'60) of the substrate at ₆₀ ° C. is preferably 10 MPa or more, more preferably 20 to 150 MPa, and even more preferably 30 to 110 MPa.

The tensile storage elastic modulus (E'80) of the substrate at 80 ° C. and the tensile storage elastic modulus ( _E'60 ) of the substrate at ₆₀ ° C. satisfy the relationship of ( _E'60 ) / ( _E'80 ) ≥ 2. Is preferable. The ratio [( _E'60 ) / ( _E'80 )] of the tensile storage elastic modulus ( _E'80 ) to the tensile storage elastic modulus ( _E'60 )] is the tensile storage elasticity of the substrate from 60 ° C to 80 ° C. It is an index of change in rate. The tensile storage elastic modulus (E'80) of the substrate at 80 ° C. and the tensile storage elastic modulus ( _E'60 ) of the substrate at ₆₀ ° C. have a relationship of 2 ≦ ( _E'60 ) / ( _E'80 ) ≦ 5. It is more preferable to satisfy the relationship of 3 ≦ ( _E'60 ) / ( _E'80 ) ≦ 4.5, and it is more preferable to satisfy the relationship of 3.5 ≦ ( _E'60 ) / ( _E'80 ) ≦ 4. It is particularly preferable to satisfy the relationship of .5.

By setting the ratio of the tensile storage elastic modulus ( _E'80 ) to the tensile storage elastic modulus ( _E'60 ) within the above range, the physical properties of the base material change due to the temperature change due to the heating of the adsorption table in the wafer back surface grinding apparatus. Be controlled. As a result, deformation of the base material in the above temperature range is prevented, and adhesion of the base material to the adsorption table is suppressed, so that the transportability is excellent.

The substrate side of the laminate in which the PET film having a thickness of 75 μm, the pressure-sensitive adhesive layer having a thickness of 20 μm, and the substrate for backgrinding tape having a thickness of 50 μm are laminated is placed on an adsorption table heated to 80 ° C. at an adsorption pressure of 85 kPa 30. The adhesive force between the substrate and the adsorption table when the laminate is peeled from the adsorption table at a peeling angle of 30 ° and a peeling speed of 300 mm / min after holding for a minute is preferably 1N or less, more preferably. It is 0.2 to 0.8 N, more preferably 0.3 to 0.5 N. By setting the adhesion of the base material within the above range, the peelability of the base material from the adsorption table is excellent.
The method for measuring the adhesion of the base material is derived from the peeling behavior at the interface between the back grind tape 10 and the adsorption table 20 shown in FIG. 7. As shown in FIG. 7, when the adhesive sheet 2 is sucked by the transport arm 4 and the laminated body of the back grind tape 10 and the wafer 1 is lifted from the suction table 20, the laminated body bends and the back grind tape 10 and the suction table are bent. The angle of the peeling surface with 20 (peeling angle α) is an acute angle. The present inventors focused on the fact that the peeling angle of the back grind tape with respect to the suction table is about 30 °, set pseudo conditions for the peeling behavior shown in FIG. 7, and set the adhesion of the base material to the suction table. It was measured. Although a specific measurement method will be described later, the "semiconductor wafer 1" shown in FIG. 7 is replaced with a "PET film" for the adsorption table under predetermined conditions (heating temperature, adsorption pressure, adsorption time, peeling speed of the adsorption table). The adhesion of the substrate was measured. The present inventors have found that the peelability of the base material from the adsorption table is further improved by setting the adhesion of the base material within a predetermined range.

The thickness of the base material is not particularly limited, but is preferably 100 μm or less, more preferably 30 to 80 μm, and even more preferably 40 to 60 μm. By setting the thickness of the base material within the above range, the stress during backside grinding can be appropriately relieved.

Further, at least one surface of the base material may be subjected to an adhesive treatment such as a corona treatment in order to improve the adhesion to the pressure-sensitive adhesive layer described later. Further, the easy-adhesive layer may be laminated on the surface of the base material on the side where the adhesive layer is laminated.

The composition for forming the easy-adhesive layer for forming the easy-adhesive layer is not particularly limited, and examples thereof include compositions containing a polyester resin, a urethane resin, a polyester urethane resin, an acrylic resin, and the like. The composition for forming an easy-adhesive layer may contain a cross-linking agent, a photopolymerization initiator, an antioxidant, a softener (plasticizer), a filler, a rust preventive, a pigment, a dye and the like, if necessary. good.
The thickness of the easy-adhesion layer is preferably 0.01 to 10 μm, more preferably 0.03 to 5 μm. Since the thickness of the easy-adhesion layer is small with respect to the thickness of the base material and the material is soft, the influence on the above physical properties such as the tensile storage elastic modulus ( _E'80 ) is small. For example, the tension of the base material is small. The storage elastic modulus ( _E'80 ) is substantially the same as the tensile storage elastic modulus ( _E'80 ) of the base material alone even when it has an easy-adhesion layer.

The composition for forming a substrate layer containing a urethane (meth) acrylate (a1) and a polymerizable compound (a2) having an energy ray-polymerizable group is cured by irradiation with energy rays. The "energy ray" refers to ultraviolet rays, electron beams, etc., and preferably ultraviolet rays are used.
The substrate made of the cured product of the composition for forming the substrate layer is excellent in stress relaxation property and expandability. Further, the composition for forming the base material layer contains the above-mentioned components (a1) and (a2) to control the above-mentioned physical properties such as the tensile storage elastic modulus ( _E'80 ) of the base material within the above-mentioned range. It will be easier. Further, the composition for forming a substrate layer is a polymerizable compound (a3) having a heterocyclic group or an alicyclic group having 6 to 20 ring-forming atoms in addition to the above components (a1) and (a2) from the above viewpoint. ) Is preferably contained. Further, the composition for forming a base material layer preferably contains a photopolymerization initiator in addition to the above-mentioned components (a1) and (a2), and has a functional group as long as the effect of the present invention is not impaired. It may contain a polymerizable compound (a4), other additives, a resin component and the like.
Hereinafter, each component contained in the composition for forming a base material layer will be described in detail.

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

The weight average molecular weight (Mw) of the component (a1) is preferably 1,000 to 100,000, more preferably 2,000 to 60,000, still more preferably 3,000 to 20,000. The number of (meth) acryloyl groups (hereinafter, also referred to as “functional number”) in the component (a1) may be monofunctional, bifunctional, or trifunctional or higher, but is preferably bifunctional.
The component (a1) can be obtained, for example, by reacting a terminal isocyanate urethane prepolymer obtained by reacting a polyol compound with a polyhydric isocyanate compound with a (meth) acrylate having a hydroxyl group. The component (a1) may be used alone or in combination of two or more.

The polyol compound used as a raw material for the component (a1) is not particularly limited as long as it is a compound having two or more hydroxy groups. Specific examples of the polyol compound include alkylene diols, polyether-type polyols, polyester-type polyols, polycarbonate-type polyols, and the like. Among these, polyester-type polyols or polycarbonate-type polyols are preferable.
The polyol compound may be any of a bifunctional diol, a trifunctional triol, and a tetrafunctional or higher functional polyol, but a bifunctional diol is preferable, and a polyester type diol or a polycarbonate type diol is more preferable.

Examples of the polyvalent isocyanate compound include aliphatic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate; isophorone diisocyanate, norbornan diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, and dicyclohexylmethane-2. , 4'-Diisocyanate, ω, ω'-diisocyanate Diisocyanate Diisocyanates such as dimethylcyclohexane; 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, trizine diisocyanate, tetramethylene xylylene diisocyanate, naphthalene- Examples thereof include aromatic diisocyanates such as 1,5-diisocyanate.
Among these, isophorone diisocyanate, hexamethylene diisocyanate, and xylylene diisocyanate are preferable.

Urethane (meth) acrylate (a1) can be obtained by reacting a (meth) acrylate having a hydroxy group with a terminal isocyanate urethane prepolymer obtained by reacting the above-mentioned polyol compound with a polyhydric isocyanate compound. The (meth) acrylate having a hydroxy group is not particularly limited as long as it is a compound having a hydroxy group and a (meth) acryloyl group in at least one molecule.

Examples of the (meth) acrylate having a hydroxy group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 4-hydroxycyclohexyl (meth) acrylate, 5 -Hydroxyalkyl such as hydroxycyclooctyl (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, pentaerythritol tri (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate. (Meta) Acrylate; Hydroxyl group-containing (meth) acrylamide such as N-methylol (meth) acrylamide; Reactant obtained by reacting diglycidyl ester of vinyl alcohol, vinylphenol, bisphenol A with (meth) acrylic acid; etc. Can be mentioned.
Among these, hydroxyalkyl (meth) acrylate is preferable, and 2-hydroxyethyl (meth) acrylate is more preferable.

As the conditions for reacting the terminal isocyanate urethane prepolymer and the (meth) acrylate having a hydroxy group, the conditions for reacting at 60 to 100 ° C. for 1 to 4 hours in the presence of a solvent and a catalyst added as necessary are preferable. ..
The content of the component (a1) in the composition for forming the base material layer is preferably 10 to 70% by mass, more preferably 20 to 60% by mass, based on the total amount (100% by mass) of the composition for forming the base material layer. It is by mass, more preferably 25 to 55% by mass, and particularly preferably 30 to 50% by mass.

(Polymerizable compound having an energy ray-polymerizable group (a2))
The polymerizable compound having an energy ray-polymerizable group means a compound having three or more energy ray-polymerizable groups. The energy ray-polymerizable group is a functional group containing a carbon-carbon double bond, and examples thereof include a (meth) acryloyl group, a vinyl group, an allyl group, and a vinylbenzyl group. Two or more types of energy ray-polymerizable groups may be combined. The energy ray-polymerizable group in the polymerizable compound having an energy ray-polymerizable group reacts with the (meth) acryloyl group in the component (a1), or the energy ray-polymerizable group in the component (a2) reacts with each other. As a result, a three-dimensional network structure (crosslinked structure) is formed. When the polymerizable compound (a2) having an energy ray-polymerizable group is used, the crosslinked structure formed by the energy ray irradiation is increased as compared with the case where the compound containing one or two energy ray-polymerizable groups is used. Therefore, the base material exhibits peculiar viscoelasticity, and it becomes easy to control the above physical properties such as the tensile storage elasticity ( _E'80 ) within the above range.

From the above viewpoint, the number of energy ray-polymerizable groups (number of functional groups) in the polymerizable compound (a2) having energy ray-polymerizable groups is preferably 3 to 10.

The weight average molecular weight of the component (a2) is preferably 200 to 3000, more preferably 300 to 800, and even more preferably 400 to 600.

Examples of the trifunctional component (a2) include trimethylolpropane tri (meth) acrylate and pentaerythritol tri (meth) acrylate.
Examples of the tetrafunctional component (a2) include pentaerythritol tetra (meth) acrylate and the like.
Examples of the pentafunctional component (a2) include dipentaerythritol penta (meth) acrylate and the like.
Examples of the hexafunctional component (a2) include dipentaerythritol hexa (meth) acrylate and the like.
The component (a2) may be used alone or in combination of two or more.
Among these, dipentaerythritol hexa (meth) acrylate is preferable.

The content of the component (a2) in the composition for forming the base material layer is preferably 1 to 50% by mass, more preferably 5 to 30% with respect to the total amount (100% by mass) of the composition for forming the base material layer. It is by mass, more preferably 5 to 10% by mass.

(Polycyclic compound (a3) having a heterocyclic group or an alicyclic group having 6 to 20 ring-forming atoms)
The component (a3) is a polymerizable compound having a heterocyclic group or an alicyclic group having 6 to 20 ring-forming atoms, and is preferably a compound having at least one (meth) acryloyl group. By using the component (a3), the film forming property of the obtained base material layer forming composition can be improved. The number of (meth) acryloyl groups in the component (a3) is more preferably 1 or 2.

The number of ring-forming atoms of the heterocyclic group contained in the component (a3) is not particularly limited, but is preferably 3 to 6. Examples of the atom forming the ring structure of the heterocyclic group include a carbon atom, a nitrogen atom, an oxygen atom, a sulfur atom and the like. The number of ring-forming atoms of the alicyclic group contained in the component (a3) is 6 to 20, preferably 6 to 18, more preferably 6 to 16, and even more preferably 7 to 12.
The number of ring-forming atoms represents the number of atoms constituting the ring itself of a compound having a structure in which atoms are ring-bonded, and atoms not forming a ring (for example, hydrogen atoms bonded to atoms constituting the ring). Or, the atom contained in the substituent when the ring is substituted by the substituent is not included in the number of ring-forming atoms.

Specific components (a3) include, for example, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyloxy (meth) acrylate, cyclohexyl (meth) acrylate, and the like. An alicyclic group-containing (meth) acrylate such as adamantan (meth) acrylate; a heterocyclic group-containing (meth) acrylate such as tetrahydrofurfuryl (meth) acrylate, morpholin (meth) acrylate, and glycidyl (meth) acrylate; ..

The component (a3) may be used alone, but it is preferable to use two or more in combination. By using two or more kinds of components (a3) in combination, it becomes easy to control the above physical properties such as the tensile storage elastic modulus ( _E'80 ), and the film forming property of the substrate layer forming composition is improved. do.
From such a viewpoint, it is more preferable to use two or three kinds of components (a3) in combination, and it is further preferable to use two kinds of components (a3) in combination. By using the component (a3) in the above combination, the composition for forming the base material layer has a simple structure, the productivity of the composition is excellent, and the cost can be reduced.

Among the alicyclic group-containing (meth) acrylates, isobornyl (meth) acrylates are preferable, and among the heterocyclic group-containing (meth) acrylates, tetrahydrofurfuryl (meth) acrylates are preferable.

When the component (a3) is contained in the composition for forming the base material layer, the content thereof is preferably 10 to 70% by mass with respect to the total amount (100% by mass) of the composition for forming the base material layer. It is preferably 20 to 60% by mass, more preferably 25 to 55% by mass.
The content ratio [(a2) / (a3)] of the component (a2) to the component (a3) in the composition for forming the base material layer is preferably 0.05 to 3.0, more preferably 0. It is .07 to 2.0, more preferably 0.08 to 1.0, and particularly preferably 0.1 to 0.5.

(Polymerizable compound having a functional group (a4))
The composition for forming a base material layer may contain a polymerizable compound (a4) having a functional group in addition to the above-mentioned components (a1) to (a3) as long as the effects of the present invention are not impaired.
The component (a4) is a polymerizable compound containing a functional group such as a hydroxyl group, an epoxy group, an amide group and an amino group, and more preferably a compound having at least one (meth) acryloyl group. The number of (meth) acryloyl groups in the component (a4) is more preferably 1 or 2. Further, the component (a4) is more preferably a compound having 6 to 20 ring-forming atoms and having no alicyclic group or heterocyclic group.
The component (a4) has good compatibility with the component (a1), and it becomes easy to adjust the viscosity of the composition for forming the base material layer to an appropriate range. Examples of the component (a4) include a hydroxyl group-containing (meth) acrylate, an epoxy group-containing compound, an amide group-containing compound, and an amino group-containing (meth) acrylate.

Examples of the hydroxyl group-containing (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 3-hydroxy. Examples thereof include butyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, phenylhydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxypropylacryllate and the like.
Examples of the epoxy group-containing compound include methyl glycidyl (meth) acrylate and allyl glycidyl ether, among which epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate and methyl glycidyl (meth) acrylate are used. Is preferable.
Examples of the amide group-containing compound include (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methylolpropane (meth) acrylamide, and N. -Crystalmethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide and the like can be mentioned.
Examples of the amino group-containing (meth) acrylate include a primary amino group-containing (meth) acrylate, a secondary amino group-containing (meth) acrylate, and a tertiary amino group-containing (meth) acrylate.

Among these, a hydroxyl group-containing (meth) acrylate is preferable, and a hydroxyl group-containing (meth) acrylate having an aromatic ring such as phenylhydroxypropyl (meth) acrylate is more preferable.
The component (a4) may be used alone or in combination of two or more.

The content of the component (a4) in the base material layer forming composition is the total amount (100% by mass) of the base material layer forming composition in order to improve the film forming property of the base material layer forming composition. On the other hand, it is preferably 0 to 40% by mass, more preferably 0 to 35% by mass, still more preferably 0 to 30% by mass, and particularly preferably 0 to 25% by mass.
The content ratio [(a3) / (a4)] of the component (a3) to the component (a4) in the composition for forming the base material layer is preferably 0.5 to 3.0, more preferably 1. It is 0.0 to 3.0, more preferably 1.3 to 3.0, and particularly preferably 1.5 to 2.8.

(Polymerizable compounds (a5) other than the components (a1) to (a4))
The composition for forming a base material layer may contain other polymerizable compounds (a5) other than the above-mentioned components (a1) to (a4) as long as the effects of the present invention are not impaired.
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, N-vinylformamide, N-vinylpyrrolidone, N-vinylcaprolactam and the like. Vinyl compounds: and the like. The component (a5) may be used alone or in combination of two or more.

The content of the component (a5) in the composition for forming the base material layer is preferably 0 to 20% by mass, more preferably 0 to 10% by mass, still more preferably 0 to 5% by mass, and particularly preferably 0 to 2%. It is mass%.

(Photopolymerization initiator)
The composition for forming a base material layer preferably further contains a photopolymerization initiator from the viewpoint of shortening the polymerization time by light irradiation and reducing the amount of light irradiation when forming the base material.
Examples of the photopolymerization initiator include benzoin compounds, acetophenone compounds, acylphosphinoxide compounds, titanosen compounds, thioxanthone compounds, peroxide compounds, and photosensitizers such as amines and quinones. Specifically, for example, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propane-1-one, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzylphenyl sulfide, etc. Tetramethylthium monosulfide, azobisisobutyrolenitrile, dibenzyl, diacetyl, 8-chloranthraquinone, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, etanone, 1- [9-ethyl-6- (2-Methylbenzoyl) -9H-carbazole-3-yl]-, 1- (o-acetyloxime) and the like can be mentioned.
These photopolymerization initiators can be used alone or in combination of two or more.
The content of the photopolymerization initiator in the composition for forming the substrate layer is preferably 0.05 to 15% by mass with respect to 100 parts by mass of the total amount of the energy ray-polymerizable components (a1) to (a5). Parts, more preferably 0.1 to 10 parts by mass, still more preferably 0.2 to 5 parts by mass.

(Other additives)
The composition for forming a base material layer may contain other additives as long as the effects of the present invention are not impaired. Examples of other additives include antistatic agents, antioxidants, softeners (plasticizers), fillers, rust inhibitors, pigments, dyes and the like. When these additives are blended, the content of each additive in the composition for forming the base material layer is 100 parts by mass based on the total amount of the energy ray-polymerizable components (a1) to (a5). It is preferably 0.01 to 6 parts by mass, and more preferably 0.1 to 3 parts by mass.

(Resin component)
The composition for forming a base material layer may contain a resin component as long as the effects of the present invention are not impaired. Examples of the resin component include polyene-thiol-based resins, 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 the substrate layer is preferably 0 to 20% by mass, more preferably 0 to 10% by mass, still more preferably 0 to 5% by mass, and particularly preferably 0 to 2%. It is mass%.

The substrate of the present invention is obtained by polymerizing and curing the composition for forming a substrate layer having the above composition by irradiation with energy rays. Therefore, the substrate of the present invention contains a polymerization unit derived from the component (a1) and a polymerization unit derived from the component (a2). Further, the substrate of the present invention preferably contains a polymerization unit derived from the component (a3), and may contain a polymerization unit derived from the component (a4) or a polymerization unit derived from the component (a5). The content ratio of each polymerization unit in the base material usually corresponds to the ratio (charge ratio) of each component constituting the base material layer forming composition. For example, when the content of the component (a1) in the composition for forming the base material layer is 10 to 70% by mass with respect to the total amount (100% by mass) of the composition for forming the base material layer, the base material is the component (a1). ) Is contained in an amount of 10 to 70% by mass. When the content of the component (a2) in the composition for forming the base material layer is 1 to 50% by mass with respect to the total amount (100% by mass) of the composition for forming the base material layer, the base material is the component (a1). ) Is contained in an amount of 1 to 50% by mass.

The tensile storage elastic modulus ( _E'80 ), ( _E'60 ), the ratio of the tensile storage elastic modulus [( _E'60 ) / ( _E'80 )] and the adhesion of the base material are, for example, of the component (a2). It can be controlled by the number of energy ray-polymerizable groups and their content (% by mass).

[Manufacturing method of base material]
The method for producing the substrate of the present invention is not particularly limited, and the substrate can be produced by a known method. For example, a base material can be produced by applying a base material layer forming composition on a release sheet, curing the composition, and removing the release sheet.

As a method of forming a base material on the release sheet, the composition for forming a base material layer is directly applied onto the release sheet by a known coating method to form a coating film, and energy rays are applied to the coating film. By irradiating, a base material can be formed.

Examples of the method for applying the composition for forming the base material layer include a spin coating method, a spray coating method, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, and a gravure coating method. Further, in order to improve the coatability, an organic solvent may be blended with the composition for forming a base material layer and coated on a release sheet in the form of a solution.

The coating film of the composition for forming the substrate layer by irradiation with energy rays may be cured by a single curing treatment or may be performed in a plurality of times. Ultraviolet rays are preferable as the energy rays to be irradiated in the curing treatment. When curing, the coating film of the substrate layer forming composition may be cured in an exposed state, but the exposed surface of the coating film is covered with another release sheet so that the coating film is not exposed. It is preferable to irradiate with energy rays to cure.

[Adhesive tape]
The adhesive tape according to the present invention has an adhesive layer on at least one surface of the above-mentioned base material for backgrinding tape.
The pressure-sensitive adhesive layer is not particularly limited as long as it has an appropriate pressure-sensitive adhesiveness at room temperature.

The thickness of the pressure-sensitive adhesive layer is preferably less than 40 μm, more preferably 5 to 35 μm, still more preferably 10 to 30 μm. When the pressure-sensitive adhesive layer is thinned in this way, the proportion of low-rigidity portions in the pressure-sensitive adhesive tape can be reduced, so that it becomes easy to prevent chipping of the semiconductor chip that occurs during backside grinding.

The pressure-sensitive adhesive layer is formed of, for example, an acrylic pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, or the like, and an acrylic-based pressure-sensitive adhesive is preferable.
Further, the pressure-sensitive adhesive layer may be formed from an energy ray-curable pressure-sensitive adhesive. When the pressure-sensitive adhesive layer is formed by an energy ray-curable pressure-sensitive adhesive, the peeling force can be reduced to 1000 mN / 50 mm or less after curing while maintaining sufficient adhesiveness before curing by energy ray irradiation. It will be possible.

Specific examples of the pressure-sensitive adhesive will be described in detail below, but these are non-limiting examples, and the pressure-sensitive adhesive layer in the present invention should not be construed as being limited to these.
Examples of the energy ray-curable adhesive include an energy ray-curable adhesive containing an energy ray-curable compound other than the adhesive resin in addition to a non-energy ray-curable adhesive resin (also referred to as “adhesive resin I”). An agent composition (hereinafter, also referred to as “X-type pressure-sensitive adhesive composition”) can be used. Further, as an energy ray-curable adhesive, an energy ray-curable adhesive resin (hereinafter, also referred to as "adhesive resin II") in which an unsaturated group is introduced into the side chain of a non-energy ray-curable adhesive resin is used. A pressure-sensitive adhesive composition (hereinafter, also referred to as “Y-type pressure-sensitive adhesive composition”) containing as a main component and not containing an energy ray-curable compound other than the pressure-sensitive adhesive resin may also be used.

Further, as the energy ray-curable pressure-sensitive adhesive, an energy ray-curable adhesive containing both X-type and Y-type, that is, an energy ray-curable adhesive resin II and an energy ray-curable compound other than the adhesive resin. A pressure-sensitive adhesive composition (hereinafter, also referred to as “XY type pressure-sensitive adhesive composition”) may be used.

Further, as the pressure-sensitive adhesive, a non-energy ray-curable pressure-sensitive adhesive composition that does not cure even when irradiated with energy rays may be used. The non-energy ray-curable pressure-sensitive adhesive composition contains at least the non-energy ray-curable adhesive resin I, while the above-mentioned energy ray-curable pressure-sensitive adhesive resin II and the energy ray-curable compound are not contained. be.

In the following description, "adhesive resin" is used as a term to refer to one or both of the above-mentioned adhesive resin I and adhesive resin II. Specific examples of the adhesive resin include acrylic resin, urethane resin, rubber resin, silicone resin and the like, but acrylic resin is preferable.
Hereinafter, the acrylic pressure-sensitive adhesive in which an acrylic resin is used as the pressure-sensitive adhesive resin will be described in more detail.

(Acrylic resin)
As the acrylic resin, the acrylic polymer (b) is used. The acrylic polymer (b) is obtained by polymerizing a monomer containing at least an alkyl (meth) acrylate, and contains a structural unit derived from the alkyl (meth) acrylate. Examples of the alkyl (meth) acrylate include those having an alkyl group having 1 to 20 carbon atoms, and the alkyl group may be linear or branched. Specific examples of alkyl (meth) acrylates include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) methacrylate, and 2-ethylhexyl (meth). ) Acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate and the like. The alkyl (meth) acrylate may be used alone or in combination of two or more.

Further, the acrylic polymer (b) preferably contains a structural unit derived from an alkyl (meth) acrylate having an alkyl group having 4 or more carbon atoms from the viewpoint of improving the adhesive strength of the pressure-sensitive adhesive layer. The number of carbon atoms of the alkyl (meth) acrylate is preferably 4 to 12, and more preferably 4 to 6. Further, the alkyl (meth) acrylate having an alkyl group having 4 or more carbon atoms is preferably an alkyl acrylate.

In the acrylic polymer (b), the alkyl (meth) acrylate having an alkyl group having 4 or more carbon atoms is relative to the total amount of monomers constituting the acrylic polymer (b) (hereinafter, also simply referred to as “total amount of monomers”). It is preferably 40 to 98% by mass, more preferably 45 to 95% by mass, and even more preferably 50 to 90% by mass.

The acrylic polymer (b) has an alkyl group having 4 or more carbon atoms, in addition to a structural unit derived from an alkyl (meth) aclate, in order to adjust the elasticity and adhesive properties of the pressure-sensitive adhesive layer. It is preferably a copolymer containing a structural unit derived from an alkyl (meth) acrylate having 1 to 3 carbon atoms. 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 (b), the alkyl (meth) acrylate having an alkyl group having 1 to 3 carbon atoms is preferably 1 to 30% by mass, more preferably 3 to 26% by mass, based on the total amount of the monomers. More preferably, it is 6 to 22% by mass.

The acrylic polymer (b) preferably has a structural unit derived from a functional group-containing monomer in addition to the structural unit derived from the above-mentioned alkyl (meth) acrylate. Examples of the functional group of the functional group-containing monomer include a hydroxyl group, a carboxy group, an amino group, an epoxy group and the like. The functional group-containing monomer reacts with a cross-linking agent described later to serve as a cross-linking starting point, or reacts with an unsaturated group-containing compound to introduce an unsaturated group into the side chain of the acrylic polymer (b). Is possible.

Examples of the functional group-containing monomer include a hydroxyl group-containing monomer, a carboxy group-containing monomer, an amino group-containing monomer, and an epoxy group-containing monomer. These monomers may be used alone or in combination of two or more. Among these, a hydroxyl group-containing monomer and a carboxy group-containing monomer are preferable, and a hydroxyl group-containing monomer is more preferable.

Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 3-hydroxybutyl (meth). ) Hydroxyalkyl (meth) acrylates such as acrylates and 4-hydroxybutyl (meth) acrylates; unsaturated alcohols such as vinyl alcohols and allyl alcohols may be mentioned.

Examples of the carboxy group-containing monomer include ethylenically unsaturated monocarboxylic acids such as (meth) acrylic acid and crotonic acid; ethylenically unsaturated dicarboxylic acids such as fumaric acid, itaconic acid, maleic acid and citraconic acid and their anhydrides thereof. , 2-Carboxyethyl methacrylate and the like.

The functional group-containing monomer is preferably 1 to 35% by mass, more preferably 3 to 32% by mass, still more preferably 6 to 30% by mass, based on the total amount of the monomers constituting the acrylic polymer (b).
In addition to the above, the acrylic polymer (b) is derived from a monomer copolymerizable with the above acrylic monomers such as styrene, α-methylstyrene, vinyltoluene, vinyl formate, vinyl acetate, acrylonitrile, and acrylamide. It may include a structural unit.

The acrylic polymer (b) can be used as a non-energy ray-curable adhesive resin I (acrylic resin). Further, as the energy ray-curable acrylic resin, a compound obtained by reacting the functional group of the acrylic polymer (b) with a compound having a photopolymerizable unsaturated group (also referred to as an unsaturated group-containing compound) is used. Can be mentioned.

The unsaturated group-containing compound is a compound having both a substituent capable of binding to the functional group of the acrylic polymer (b) and a photopolymerizable unsaturated group. Examples of the photopolymerizable unsaturated group include a (meth) acryloyl group, a vinyl group, an allyl group, a vinylbenzyl group and the like, and a (meth) acryloyl group is preferable. Examples of the substituent that can be bonded to the functional group of the unsaturated group-containing compound include an isocyanate group and a glycidyl group.
Therefore, examples of the unsaturated group-containing compound include (meth) acryloyloxyethyl isocyanate, (meth) acryloyl isocyanate, and glycidyl (meth) acrylate.

Further, the unsaturated group-containing compound preferably reacts with a part of the functional group of the acrylic polymer (b), specifically, 50 to 98 mol of the functional group of the acrylic polymer (b). % Is preferably reacted with an unsaturated group-containing compound, more preferably 55 to 93 mol%. As described above, in the energy ray-curable acrylic resin, a part of the functional group remains without reacting with the unsaturated group-containing compound, so that the resin is easily crosslinked by the cross-linking agent.
The weight average molecular weight (Mw) of the acrylic resin is preferably 300,000 to 1.6 million, more preferably 300,000 to 1.4 million, and even more preferably 300,000 to 1.2 million.

(Energy ray curable compound)
As the energy ray-curable compound contained in the X-type or XY-type pressure-sensitive adhesive composition, a monomer or oligomer having an unsaturated group in the molecule and capable of polymerizing and curing by energy beam irradiation is preferable.
Examples of such an energy ray-curable compound include trimethyl propanthry (meth) acrylate, pentaerythritol (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and 1,4-. Polyvalent (meth) acrylate monomers such as butylene glycol di (meth) acrylate, 1,6-hexanediol (meth) acrylate, urethane (meth) acrylate, polyester (meth) acrylate, polyether (meth) acrylate, epoxy ( Examples thereof include oligomers such as meth) acrylates.

Among these, urethane (meth) acrylate oligomers are preferable from the viewpoint of having a relatively high molecular weight and not easily reducing the tensile elastic modulus of the pressure-sensitive adhesive layer.
The molecular weight of the energy ray-curable compound (weight average molecular weight in the case of an oligomer) is preferably 100 to 12000, more preferably 200 to 10000, still more preferably 400 to 8000, and particularly preferably 600 to 6000.

The content of the energy ray-curable compound in the X-type pressure-sensitive adhesive composition is preferably 40 to 200 parts by mass, more preferably 50 to 150 parts by mass, and further preferably 60 to 60 parts by mass with respect to 100 parts by mass of the pressure-sensitive adhesive resin. 90 parts by mass.
On the other hand, the content of the energy ray-curable compound in the XY type pressure-sensitive adhesive composition is preferably 1 to 30 parts by mass, more preferably 2 to 20 parts by mass, still more preferably, with respect to 100 parts by mass of the pressure-sensitive adhesive resin. Is 3 to 15 parts by mass. In the XY type pressure-sensitive adhesive composition, since the pressure-sensitive adhesive resin is energy ray-curable, it is possible to sufficiently reduce the peeling force after energy ray irradiation even if the content of the energy ray-curable compound is small. Is.

(Crosslinking agent)
The pressure-sensitive adhesive composition preferably further contains a cross-linking agent. The cross-linking agent, for example, reacts with a functional group derived from a functional group monomer of the adhesive resin to crosslink the adhesive resins with each other. Examples of the cross-linking agent include isocyanate-based cross-linking agents such as tolylene diisocyanate, hexamethylene diisocyanate, and their adducts; epoxy-based cross-linking agents such as ethylene glycol glycidyl ether; hexa [1- (2-methyl) -aziridinyl. ] An aziridine-based cross-linking agent such as trifoosphatriazine; a chelate-based cross-linking agent such as an aluminum chelate; and the like. These cross-linking agents may be used alone or in combination of two or more.

Among these, an isocyanate-based cross-linking agent is preferable from the viewpoint of increasing the cohesive force and improving the adhesive force, and from the viewpoint of easy availability.
From the viewpoint of accelerating the cross-linking reaction, the amount of the cross-linking agent is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 9 parts by mass, and further preferably 0 with respect to 100 parts by mass of the adhesive resin. It is 0.05 to 8 parts by mass.

(Photopolymerization initiator)
When the pressure-sensitive adhesive composition is energy ray-curable, the pressure-sensitive adhesive composition preferably further contains a photopolymerization initiator. By containing the photopolymerization initiator, the curing reaction of the pressure-sensitive adhesive composition can be sufficiently proceeded even with relatively low-energy energy rays such as ultraviolet rays.

Examples of the photopolymerization initiator include benzoin compounds, acetophenone compounds, acylphosphinoxide compounds, titanosen compounds, thioxanthone compounds, peroxide compounds, and photosensitizers such as amines and quinones. Specifically, for example, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propane-1-one, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl phenyl. Examples thereof include sulphide, tetramethylthium monosulfide, azobisisobutyrolenitrile, dibenzyl, diacetyl, 8-chloranthraquinone, bis (2,4,6-trimethylbenzoyl) phenylphosphin oxide and the like.

These photopolymerization initiators may be used alone or in combination of two or more.
The blending amount of the photopolymerization initiator is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 5 parts by mass, and further preferably 0.05 to 5 parts by mass with respect to 100 parts by mass of the adhesive resin. Is.

(Other additives)
The pressure-sensitive adhesive composition may contain other additives as long as the effects of the present invention are not impaired. Examples of other additives include antistatic agents, antioxidants, softeners (plasticizers), fillers, rust inhibitors, pigments, dyes and the like. When these additives are blended, the blending amount of the additives is preferably 0.01 to 6 parts by mass with respect to 100 parts by mass of the adhesive resin.

Further, the pressure-sensitive adhesive composition may be further diluted with an organic solvent in the form of a solution of the pressure-sensitive adhesive composition from the viewpoint of improving the applicability to the above-mentioned base material and the release sheet described later.
Examples of the organic solvent include methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexane, n-hexane, toluene, xylene, n-propanol, isopropanol and the like.
As these organic solvents, the organic solvent used at the time of synthesizing the pressure-sensitive adhesive resin may be used as it is, or other than the organic solvent used at the time of synthesis so that the solution of the pressure-sensitive adhesive composition can be uniformly applied. One or more organic solvents of the above may be added.

(Release sheet)
A release sheet may be attached to the surface of the adhesive tape. Specifically, the release sheet is attached to the surface of the pressure-sensitive adhesive layer of the adhesive tape. The release sheet is attached to the surface of the adhesive layer to protect the adhesive layer during transportation and storage. The release sheet is detachably attached to the adhesive tape, and is removed from the adhesive tape before the adhesive tape is used (that is, before grinding the back surface of the wafer).
As the release sheet, a release sheet having at least one surface subjected to a release treatment is used, and specific examples thereof include a release sheet coated with a release agent on the surface of the base material for the release sheet.

A resin film is preferable as the base material for the release sheet, and examples of the resin constituting the resin film include a polyester resin film such as polyethylene terephthalate resin, polybutylene terephthalate resin, and polyethylene naphthalate resin, polypropylene resin, and polyethylene resin. Polyethylene resin and the like can be mentioned. Examples of the release agent 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, and fluorine-based resins.
The thickness of the release sheet is not particularly limited, but is preferably 10 to 200 μm, more preferably 20 to 150 μm.

[Manufacturing method of adhesive tape]
The method for producing the adhesive tape of the present invention is not particularly limited, and the adhesive tape can be produced by a known method.
For example, the adhesive layer provided on the release sheet is attached to the substrate provided by coating and curing the composition for forming the substrate layer on the release sheet, and the release sheet attached to the surface of the substrate is attached. By removing it, an adhesive tape having a release sheet attached to the surface of the adhesive layer can be manufactured. The release sheet attached to the surface of the pressure-sensitive adhesive layer may be appropriately peeled off and removed before using the pressure-sensitive adhesive tape.

As a method of forming the pressure-sensitive adhesive layer on the release sheet, a pressure-sensitive adhesive (adhesive composition) is directly applied on the release sheet by a known coating method, and the coating film is heated and dried to obtain a pressure-sensitive adhesive. Layers can be formed.

Further, the pressure-sensitive adhesive (adhesive composition) may be directly applied to one side of the base material to form a pressure-sensitive adhesive layer. Examples of the method for applying the pressure-sensitive adhesive include the spin coating method shown in the method for producing a base material.

[Manufacturing method of semiconductor devices]
The adhesive tape according to the present invention is preferably used in a method for manufacturing a semiconductor device, which comprises a step of heating a semiconductor wafer on a suction table.
As a non-limiting example of the use of the adhesive tape, a method for manufacturing a semiconductor device will be described in more detail below.

Specifically, the method for manufacturing a semiconductor device includes at least the following steps 1 to 3.
Step 1: The above adhesive tape is attached to the front surface of the semiconductor wafer. Step 2: The semiconductor wafer with the adhesive tape attached to the front surface is ground from the back surface side. Step 3: The ground semiconductor wafer is attached to the suction table. The process of heating with

Hereinafter, each step of the method for manufacturing the semiconductor device will be described in detail.
(Step 1)
In step 1, the adhesive tape according to the present invention is attached to the surface of the semiconductor wafer. The semiconductor wafer may be a silicon wafer, a wafer such as gallium arsenide or arsenide, or a glass wafer. The thickness of the semiconductor wafer before grinding is not particularly limited, but is usually about 500 to 1000 μm. Further, a circuit is usually formed on the surface of a semiconductor wafer. The circuit can be formed on the wafer surface by various methods including a conventionally used general-purpose method such as an etching method and a lift-off method.
The adhesive tape is generally attached to the surface of the semiconductor wafer by a device called a mounter, but is not particularly limited. The semiconductor wafer to which the adhesive tape is attached is placed on a suction table via the adhesive tape, and is sucked and held. That is, the base material of the adhesive tape and the suction table are in contact with each other.

(Step 2)
After step 1, the back surface of the semiconductor wafer is ground on a suction table to obtain a wafer having a predetermined thickness. The back surface grinding is performed by a known method using a grinder. After the back surface grinding step, a process of removing the crushed layer generated by grinding may be performed. The thickness of the semiconductor wafer after backside grinding is not particularly limited, but is preferably about 10 to 400 μm, more preferably about 25 to 300 μm.
After the back surface grinding process, a ring frame concentric with the semiconductor wafer is placed on the suction table.

(Step 3)
After step 2, the semiconductor wafer is heated on the adsorption table. More specifically, the adhesive sheet is attached to the back surface of the wafer while heating the semiconductor wafer on the suction table. When the wafer attachment area on the suction table is heated to about 60 to 80 ° C., heat is propagated to the semiconductor wafer via the adhesive tape.
The method of attaching the adhesive sheet to the back surface of the semiconductor wafer is not particularly limited, and the adhesive sheet is attached using, for example, a mounter. After the long adhesive sheet is attached to the semiconductor wafer and the ring frame, the long adhesive sheet may be cut into a ring frame shape, or an adhesive sheet having the same shape as the ring frame may be attached. The "adhesive sheet" is a film-like adhesive used for adhering a semiconductor chip to a substrate or another chip, a laminate of a film-like adhesive and a release sheet, a dicing tape and a film-like adhesive. A dicing / die bonding tape composed of an adhesive layer having the functions of both a dicing tape and a dicing tape and a release sheet. When a film-like adhesive is used, a film-like adhesive having the same shape as the wafer is used.

After that, the adhesive sheet is adsorbed by the transport arm and peeled off at the interface between the adhesive tape and the adsorption table. Then, the semiconductor device is manufactured through a peeling step of the adhesive tape, a dicing step, a die bonding step, and the like.
Since the substrate of the present invention has heat resistance and does not adhere to the adsorption table even when the adsorption table is heated, it can be effectively used in the method for manufacturing a semiconductor device having this step. According to the adhesive tape of the present invention, since the base material is prevented from adhering to the adsorption table, the adhesive tape has excellent peelability from the adsorption table, and the wafer can be efficiently conveyed to the subsequent process.

Although the example of using the adhesive tape of the present invention in the back surface grinding step of the semiconductor wafer has been described above, the adhesive tape of the present invention can also be used in the pre-dicing method. The pre-dicing method is a method in which a groove having a predetermined depth is formed from the front surface side of the wafer by a dicing blade, then grinding is performed from the back surface side of the wafer, and the wafer is fragmented by grinding. Further, the adhesive tape of the present invention can also be used as a modification of the pre-dicing method, in which a modified region is provided inside the wafer by a laser and the wafer is separated by stress at the time of grinding the back surface of the wafer. It is possible. Further, it can also be used to temporarily fix the workpiece during processing of glass, ceramics and the like. It can also be used as various re-peelable adhesive tapes.

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

The measurement method and evaluation method in the present invention are as follows.
[Tension storage elastic modulus]
For the base material produced in Examples or Comparative Examples, a dynamic viscoelasticity measuring device (RHEOVIBRON DDV-01FP manufactured by A & D Co., Ltd.) was used in accordance with ISO6721-4 1994 (JIS K7424-4 1999). The tensile storage elastic modulus at 60 ° C. or 80 ° C. at mode: tension, frequency: 1 Hz was determined.

[Adhesion]
An acrylic pressure-sensitive adhesive (PK (manufactured by Lintec Corporation)) was applied to a PET film (manufactured by Lintec Corporation, trade name "SP-PET38131") and dried to form a pressure-sensitive adhesive layer having a thickness of 20 μm. The base material prepared in Example or Comparative Example was laminated on the pressure-sensitive adhesive layer side of the PET film and punched to a diameter of 8 inches to prepare a sample for adhesion force measurement.

Next, a product name "Adwill D-210" manufactured by Lintec Corporation was cut out to a width of 25 mm and a length of 100 mm to obtain a peeling tape.

Then, a peeling tape was attached to a region of 10 mm from the outer edge of the sample toward the center of the sample. FIG. 4 is a perspective view showing a state in which a peeling tape is attached to the outer edge of the sample for measuring the adhesion force. In FIG. 4, reference numeral 6 is a substrate, reference numeral 5 is an adhesive layer, reference numeral 11 is a PET film, and reference numeral 30 is a peeling tape. Further, FIG. 5 shows a cross-sectional view taken along the line AA of FIG.

Then, the sample was placed on an adsorption table and sucked at an adsorption pressure of 85 kPa. The temperature of the sample pasting area on the adsorption table was 80 ° C. Further, as a suction table, a ceramic suction table having a porous structure attached to RAD-2510 was attached to a mounter "RAD-2510F / 12" manufactured by Lintec Corporation.
The sample was adsorbed and held for 30 minutes in such a state.

After that, a push-pull gauge is attached to the tip of the peeling tape, and as shown in FIG. 6, the push-pull gauge (not shown) is pulled with respect to the suction table at a peeling angle of 30 ° and a peeling speed of 300 mm / min to suck the sample. It peeled off from the table. The maximum peeling force was measured for the three samples, and the average value was taken as "adhesion force".

[Transportability]
Adhesive tapes produced in Examples and Comparative Examples were attached to the mirror surface side of a mirror wafer (diameter 8 inches, thickness 720 μm) using a laminator (manufactured by Lintec Corporation, product name: RAD-3510F / 12). The wafer to which the adhesive tape was attached was fixed to a suction table of a wafer backside grinder (manufactured by DISCO, product name: DFP8760) so that the base material of the adhesive tape was in contact with the wafer, and the wafer was ground to a thickness of 50 μm. Next, the ring frame was placed concentrically with the wafer on the suction table.

Then, after heating the wafer sticking area on the suction table and setting the temperature of the wafer sticking area to 80 ° C., a mounter (manufactured by Lintec Corporation, product name: RAD-2700F / 12) is used on the ground surface of the wafer and the ring frame. A dicing die bonding tape was attached. The adsorption pressure of the adsorption table was 85 kPa.
In such a state, the wafer on the adhesive tape was adsorbed and held for 30 minutes.

Then, the dicing / die bonding tape was adsorbed by the transfer arm and peeled off at the interface between the adsorption table and the adhesive tape to transfer the wafer. When the peeling was performed well at the interface between the suction table and the adhesive tape and the tape could be transported, it was evaluated as "good". On the other hand, the case where the base material of the adhesive tape adhered to the adsorption table and could not be transported was evaluated as "defective".

In addition, all the mass parts of the following Examples and Comparative Examples are in terms of solid content.

[Example 1]
(1) Preparation of Composition for Forming Base Material Layer A 2-hydroxyethyl acrylate is reacted with a terminal isocyanate urethane prepolymer obtained by reacting a polycarbonate diol with an isophorone diisocyanate to obtain a weight average molecular weight (Mw). About 5000 urethane acrylate-based oligomers were obtained.

50 parts by mass of the urethane acrylate-based oligomer synthesized above, 30 parts by mass of isobornyl acrylate (IBXA), 20 parts by mass of tetrahydrofurfuryl acrylate (THFA), and 10 parts by mass of dipentaerythritol hexaacrylate (DPHA) are blended. Further, 0.3 parts by mass of 2-hydroxy-2-methyl-1-phenyl-propane-1-one (manufactured by BASF Japan, product name "Irgacure 1173") as a photopolymerization initiator, and etanone, 1-[ 9-ethyl-6- (2-methylbenzoyl) -9H-carbazole-3-yl]-, 1- (o-acetyloxime) (manufactured by BASF Japan, product name "Irgacure OXE02") 0.03 part by mass It was blended to prepare a composition for forming a substrate layer.

(2) Preparation of pressure-sensitive adhesive composition 84 parts by mass of n-butyl acrylate (BA), 10 parts by mass of methyl methacrylate (MMA), 1 part by mass of acrylic acid (AA), and 5 parts by mass of 2-hydroxyethyl acrylate (2HEA). Was copolymerized to obtain an acrylic polymer (b) having a weight average molecular weight of about 300,000. 100 parts by mass of this acrylic polymer (b) is dissolved in an organic solvent (ethyl acetate: toluene = 1: 1) to make a 40% by mass solution, and a polyvalent isocyanate compound (manufactured by Nippon Polyurethane Industry Co., Ltd., product name) is used as a cross-linking agent. "Coronate L") 8 parts by mass (solid ratio) was added and mixed to prepare a pressure-sensitive adhesive composition.

(3) Preparation of Base Material The composition for forming the base material layer obtained above was applied to the peeling-treated surface of the release sheet (manufactured by Lintec Corporation, trade name "SP-PET38131") to form a coating film. .. Next, the coating film was irradiated with ultraviolet rays, and the coating film was semi-cured to form a substrate layer forming film having a thickness of 50 μm.
For the above-mentioned ultraviolet irradiation, a belt conveyor type ultraviolet irradiation device (manufactured by Eye Graphics Co., Ltd., device name "US2-0801") and a high-pressure mercury lamp (manufactured by Eye Graphics Co., Ltd., device name "H08-L41") are used. The irradiation was performed under irradiation conditions of a lamp height of 210 mm, an output of 80 W / cm, an illuminance of 110 mW / cm ² with a light wavelength of 365 nm, and an irradiation amount of 50 mJ / cm ² .

Then, another release sheet is attached to the surface of the formed substrate layer forming film, and ultraviolet rays are irradiated again to completely cure the substrate layer forming film, and the release sheet laminated on both sides is removed. A substrate having a thickness of 50 μm was obtained. The above-mentioned ultraviolet irradiation uses the above-mentioned ultraviolet irradiation device and high-pressure mercury lamp, and irradiates with a lamp height of 175 mm, a conversion output of 160 mW / cm, an illuminance of 310 mW / cm ² with a light wavelength of 365 nm, and an irradiation amount of 420 mJ / cm ² . It was performed under the conditions.

(4) Preparation of Adhesive Tape The above pressure-sensitive adhesive composition is applied to the peel-processed surface of the peel-off sheet (manufactured by Lintec Corporation, trade name "SP-PET38131") and dried by heating to obtain a 20 μm-thick adhesive. An agent layer was formed. Then, the pressure-sensitive adhesive layer was attached to one surface of the base material, and the release sheet on the pressure-sensitive adhesive layer was removed to prepare an adhesive tape.

[Example 2]
An adhesive tape was obtained in the same manner as in Example 1 except that the blending amount of DPHA was changed to 6 parts by mass in the preparation of the composition for forming the base material layer.

[Comparative Example 1]
An adhesive tape was obtained in the same manner as in Example 1 except that the blending amount of DPHA was changed to 0 parts by mass in the preparation of the composition for forming the base material layer.

[Comparative Example 2]
An adhesive tape was obtained in the same manner as in Example 1 except that the blending amount of DPHA was changed to 2 parts by mass in the preparation of the composition for forming the base material layer.

1 ... Wafer 2 ... Adhesive sheet 3 ... Ring frame 4 ... Conveyor arm 10 ... Back grind tape 20 ... Suction table

Claims (6)

A cured product of a substrate layer forming composition containing a urethane (meth) acrylate and a polymerizable compound having an energy ray-polymerizable group.
The number of energy ray-polymerizable groups in the polymerizable compound having energy ray-polymerizable groups is 3 or more.
A substrate for backgrinding tape having a tensile storage elastic modulus of 8 MPa or more at 80 ° C. The substrate side of the laminate in which the PET film having a thickness of 75 μm, the pressure-sensitive adhesive layer having a thickness of 20 μm, and the substrate for backgrinding tape having a thickness of 50 μm are laminated is placed on an adsorption table heated to 80 ° C. at an adsorption pressure of 85 kPa 30. The first aspect of claim 1, wherein the adhesion between the base material and the suction table when peeling the laminate at a peeling angle of 30 ° and a peeling speed of 300 mm / min with respect to the suction table after holding for a minute is 1N or less. Back grind tape base material. The base material for backgrinding tape according to claim 1 or 2 , wherein the content of the polymerizable compound having an energy ray-polymerizable group is 5 to 10% by mass with respect to the total amount of the composition for forming a base material layer. The substrate for backgrinding tape according to any one of claims 1 to 3 , wherein the composition for forming a substrate layer contains a heterocyclic group or a polymerizable compound having an alicyclic group having 6 to 20 ring-forming atoms. The base material for backgrinding tape according to claim 4 , wherein the composition for forming a base material layer contains two or more kinds of the heterocyclic group or a polymerizable compound having an alicyclic group having 6 to 20 ring-forming atoms. An adhesive tape having an adhesive layer on at least one side of the substrate for backgrinding tape according to any one of claims 1 to 5 .

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