JP2018115331A - Pressure-sensitive adhesive tape and production method of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure-sensitive adhesive tape with which a chip can be stably held even when dry polishing is conducted in a so-called pre-dicing method.SOLUTION: A pressure-sensitive adhesive tape includes a substrate and a pressure-sensitive adhesive layer arranged on one surface of the substrate, in which an absolute value of TMA value at 60°C of the substrate is 30 μm or less. In the pressure-sensitive adhesive tape, an absolute value of a dimensional change rate of the substrate after being held at 60°C for 3 minutes is 0.8% or less, and an elasticity change rate Ecalculated from a tensile elastic modulus (E) at 23°C and a tensile elastic modulus (E) at 60°C is 30% or less. The pressure-sensitive adhesive tape is stuck to a surface of a semiconductor wafer in a step of converting the wafer into individual semiconductor chips by grinding the rear surface of the semiconductor wafer.SELECTED DRAWING: None

Description

  The present invention relates to an adhesive tape, and more particularly, an adhesive tape that is preferably used for temporarily fixing a semiconductor wafer or a chip when a semiconductor device is manufactured by a so-called tip dicing method, and a semiconductor using the adhesive tape The present invention relates to a device manufacturing method.

  As various electronic devices are becoming smaller and more multifunctional, semiconductor chips mounted on them are also required to be smaller and thinner. In order to reduce the thickness of the chip, the thickness is generally adjusted by grinding the back surface of the semiconductor wafer. In addition, after forming a groove of a predetermined depth from the front side of the wafer, grinding is performed from the back side of the wafer, the bottom of the groove is removed by grinding, the wafer is singulated, and a method called a prior dicing method is used to obtain a chip. Sometimes used. In the first dicing method, the back surface grinding of the wafer and the wafer singulation can be performed simultaneously, so that a thin chip can be efficiently manufactured.

  Conventionally, when grinding a back surface of a semiconductor wafer or manufacturing a chip by a pre-dicing method, a circuit on the surface of the wafer is protected, and the semiconductor wafer and the semiconductor chip are fixed, so that the wafer surface is called a back grind sheet. It is common to stick an adhesive tape.

  As a back grind sheet used in the prior dicing method, an adhesive tape including a base material and an adhesive layer provided on one surface of the base material is used. As an example of such an adhesive tape, Japanese Patent Application Laid-Open No. 2008-251934 (Patent Document 1) proposes an adhesive tape for processing a semiconductor wafer in which a radiation curable adhesive layer is provided on a base film.

  When wafers are singulated by the tip dicing method as described above, back surface grinding is performed while supplying water to the grinding surface in order to remove heat and grinding debris generated during the back surface grinding. However, in such conventional backside grinding, grinding marks remain on the backside of the chip and minute chipping (chipping) occurs at the end of the chip, which proves to be a factor that impairs the die bending strength of the chip. did. In particular, as a result of the thinning of the chip, the chip is easily damaged, and a decrease in the bending strength is regarded as a problem.

JP 2008-251934 A

  In order to remove the above-mentioned grinding marks and chip chips (hereinafter, these may be collectively referred to as “damaged parts”), water is finally used after the backside grinding with water. It has been studied to remove the damaged portion by dry polishing, which improves the bending strength of the chip. However, since no water is used during dry polishing, the chips are heated. The heat of the chip propagates to the adhesive tape. As a result, the substrate temperature of the adhesive tape may be 60 ° C. or higher during dry polishing.

  Since the base material of the adhesive tape is formed from a resin film, it is easily deformed by heat. At the time of back surface grinding, suction is performed from the substrate surface side of the adhesive tape to fix the adhesive tape, but the suction force may be insufficient at the end of the adhesive tape. At this time, if the base material of the adhesive tape is slightly deformed by heat, the end of the adhesive tape may be curled due to insufficient fixation of the adhesive tape at the end. As a result, the chip on the adhesive tape is peeled off. Chip peeling not only reduces yield, but the chip that comes off touches other chips and damages other chips, damages the grinding machine, and causes poor conveyance to the next process. .

  Accordingly, an object of the present invention is to provide an adhesive tape that can stably hold a wafer, a chip, or the like during processing of a semiconductor wafer or the like. In particular, an object of the present invention is to provide an adhesive tape that can stably hold a chip even when dry polishing is performed in a so-called tip dicing method.

The gist of the present invention aimed at solving such problems is as follows.
(1) A pressure-sensitive adhesive tape comprising a base material and a pressure-sensitive adhesive layer provided on one side thereof,
The adhesive tape whose absolute value of the 60 degreeC TMA value of the said base material is 30 micrometers or less.
(2) The pressure-sensitive adhesive tape according to (1), wherein an absolute value of a dimensional change rate after holding the substrate at 60 ° C. for 3 minutes is 0.8% or less.
(3) Tensile modulus at 23 ° C. of the substrate _{(E 23)} and the tensile modulus at 60 ° C. _{(E 60)} because obtained elastic modulus change rate _{E (23-60)} is 30% or less (1 ) Or (2).
(4) In the step of grinding the back surface of the semiconductor wafer having grooves formed on the surface of the semiconductor wafer and separating the semiconductor wafer into semiconductor chips by the grinding, the semiconductor wafer is used by being attached to the surface of the semiconductor wafer. The adhesive tape in any one of 1)-(3).
(5) The pressure-sensitive adhesive tape according to (4), comprising a step of dry polishing after the semiconductor wafer is separated into semiconductor chips.
(6) forming a groove from the surface side of the semiconductor wafer;
Attaching the adhesive tape according to any one of the above (1) to (4) to the surface of the semiconductor wafer;
A step of grinding the semiconductor wafer with the adhesive tape affixed to the front surface and the groove formed from the back side, removing the bottom of the groove and dividing it into a plurality of chips;
Peeling the adhesive tape from the plurality of chips;
A method for manufacturing a semiconductor device comprising:
(7) The method of manufacturing a semiconductor device according to (6), including a step of performing dry polishing after the semiconductor wafer is separated into semiconductor chips.

The pressure-sensitive adhesive tape according to the present invention can prevent curling during dry polishing by suppressing the deformation of the substrate due to heat to a very low level. For this reason, a semiconductor chip can be manufactured with a high yield even by a prior dicing method including a dry polishing process.
In addition, since the pressure-sensitive adhesive tape of the present invention is suppressed to an extremely low level of thermal deformation, it can be used in a normal back grinding process.

Hereinafter, the adhesive tape according to the present invention will be specifically described. 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.

An adhesive tape means the laminated body containing a base material and the adhesive layer provided in the single side | surface, and does not prevent including other structural layers other than these. For example, a primer layer may be formed on the base material surface on the pressure-sensitive adhesive layer side for the purpose of improving adhesion at the interface between the base material surface and the pressure-sensitive adhesive layer or preventing migration of low molecular weight components. On the surface, a release sheet for protecting the pressure-sensitive adhesive layer until use can be laminated. Further, the substrate 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.
Dividing the semiconductor wafer into pieces means dividing the semiconductor wafer into circuits to obtain semiconductor chips.

Dry polishing means a process of polishing with a polishing puff without using water or abrasive slurry. As the polishing puff, various general-purpose polishing puffs are used, and as a commercial product, a polishing wheel “Gettering DP” or “DP08 SERIES” manufactured by Disco Corporation is used, but is not limited thereto. The damaged portion of the chip, that is, the grinding mark or the chip (chipping) of the chip is removed by dry polishing.
The pre-dicing method refers to a method in which after a groove having a predetermined depth is formed from the front surface side of the wafer, grinding is performed from the back surface side of the wafer, and the wafer is separated into pieces by grinding.

Next, the structure of each member of the adhesive tape of this invention is demonstrated in detail.
[Base material]
(Substrate physical properties)
As the base material of the adhesive tape, a film or sheet having an absolute value of 60 ° C. TMA value of 30 μm or less is used.
The absolute value of the 60 ° C. TMA value is 15 g (width) × 10 mm (length) measuring film made of the same material as the film or sheet constituting the substrate, and the load is increased by 2 g using BRUKER 4000SA. The elongation or shrinkage of the measurement film is measured at a temperature rate of 5 ° C./min (TMA value), and the absolute value at 60 ° C. is referred to. Measurement conditions other than the above are set according to the operation manual of the measuring apparatus. When the measurement film is stretched, the TMA value is positive, and when it is shrunk, it is negative. In this specification, it measures about 10 or more samples, averages the obtained TMA value, and evaluates by an absolute value.

  The absolute value of the 60 ° C. TMA value is one of the indices of base material deformability at 60 ° C., and the lower the value, the more the deformation is suppressed. Therefore, a base material having an absolute value of 60 ° C. TMA of 30 μm or less has very little thermal deformation at 60 ° C. Polyvinyl chloride, which is widely used as a base material for adhesive tapes, has a thickness of about 40 μm, and ethylene / methacrylic acid copolymer has a thickness of about 220 μm.

  When the absolute value of the 60 ° C. TMA value is 30 μm or less, deformation is suppressed even when the adhesive tape is heated to around 60 ° C. during dry polishing, and chip peeling at the end of the adhesive tape is reduced. Although not theoretically constrained at all, the mechanism of the manifestation of such an effect is estimated as follows. Semiconductor wafers are increasing in diameter to 6 inches, 8 inches, or even 12 inches. A surplus area where no circuit is formed is formed on the outer periphery of the wafer. The adhesive tape attached to the circuit surface of the wafer at the time of back surface grinding or tip dicing is approximately the same size as the semiconductor wafer. If the absolute value of the 60 ° C. TMA value is in the above range and the adhesive tape has a relatively large area, the influence of the thermal deformation of the base material is slight as a whole, so the end of the adhesive tape is slightly curled. However, the effect remains in the surplus area and does not cause the product chip to peel off or drop off. Further, deformation of the adhesive tape in the surplus area is small, and dropping of the waste chip in the surplus area is reduced. On the other hand, if the absolute value of the 60 ° C. TMA value exceeds 30 μm, curling of the adhesive tape due to thermal deformation of the base material also reaches the circuit formation region, so that many product chips and excess region chips are peeled off and dropped, yield. In addition to causing a decrease in the thickness, the peeled chip contacts another chip and breaks the other chip, damages the grinding apparatus, or causes a conveyance failure to the next process.

  The absolute value of the 60 ° C. TMA value of the substrate is preferably 5 to 25 μm. More preferably, it is 10-20 micrometers.

  The absolute value of the 60 ° C. TMA value is preferably as low as possible, but a substrate that is too low often lacks flexibility and is preferably in the above range. When the substrate is excessively hard, the sticking property is inferior, pressure is applied to the circuit surface during back surface grinding, and chipping (chipping) of the chip may occur or the circuit and bump electrode may be damaged. However, when the film is sufficiently flexible, the absolute value of the 60 ° C. TMA value may be 5 μm or less, or 7 μm or less.

  Further, the absolute value of the dimensional change rate after holding the substrate at 60 ° C. for 3 minutes is preferably 0.8% or less. The measurement of the dimensional change rate conforms to JIS C2151, ASTM D1204, but the measurement temperature is 60 ° C. and the holding time is 3 minutes.

The dimensional change rate is measured using a 10 cm × 10 cm measuring film made of the same material as the film or sheet constituting the substrate. The dimensions of the measurement film are measured values at 23 ° C. The measurement sample is allowed to stand at a predetermined temperature for a predetermined time in a hot-air circulating thermostat. Then, after cooling to room temperature (23 ° C.), the following equation is obtained from the length of one side at 23 ° C. before heating (10 cm: L ₀ ) and the length of the same side at 23 ° C. after heating (L ₁ ). Obtain the rate of dimensional change. In this specification, it measures about 10 or more samples, averages the obtained dimensional change rate, and evaluates it by an absolute value. In addition, the measured value in the MD direction is used as the measured value.
Dimensional change rate (%) = 100 × (L ₀ −L ₁ ) / L ₀

  The absolute value of the dimensional change rate at 60 ° C. for 3 minutes is one of the indicators of the deformability of the substrate at 60 ° C., and the lower the value, the more the deformation is suppressed. Accordingly, a base material having an absolute value of the dimensional change rate at 60 ° C. for 3 minutes of 0.8% or less has very little thermal deformation at 60 ° C. It is about 0.9% for polyvinyl chloride, which is widely used as a base material for adhesive tapes, and about 1% for ethylene / methacrylic acid copolymers.

  When the absolute value of the dimensional change rate at 60 ° C. for 3 minutes is 0.8% or less, deformation is suppressed even when the adhesive tape is heated to around 60 ° C. during dry polishing, and the chip is peeled off at the end of the adhesive tape. Is reduced. Although it is not theoretically constrained at all, the mechanism of the effect is similar to the above TMA value, and the influence of the thermal deformation of the base material is slight as a whole. Even if it is curled, it is considered that the effect remains in the surplus area and does not cause the product chip to peel off or fall off. Further, deformation of the adhesive tape in the surplus area is small, and chipping of the chip in the surplus area is reduced. On the other hand, if the absolute value of the dimensional change rate at 60 ° C. for 3 minutes exceeds 0.8%, curling of the adhesive tape due to thermal deformation of the base material also reaches the circuit formation region, so that the product chip or the chip in the surplus region Not only causes a large number of peeling and dropping, leading to a decrease in yield, but also the chip that has peeled contacts other chips and breaks other chips, damages the grinding machine, and transports to the next process. It may cause defects.

  The lower the absolute value of the dimensional change rate at 60 ° C. for 3 minutes, the better the result, and more preferably 0 to 0.5%. Moreover, in another aspect of this invention, 0.5 to 0.8% may be sufficient. The absolute value of the dimensional change rate of the substrate at 60 ° C. for 3 minutes is more preferably 0 to 0.2%, and most preferably 0%.

Further, the thermal deformability of the base material can be evaluated by the rate of change of the tensile elastic modulus at a predetermined temperature with respect to the tensile elastic modulus at normal temperature. From the tensile elastic modulus (E ₂₃ ) at normal temperature (23 ° C.) and the tensile elastic modulus (E _n ) at a predetermined temperature (n ° C.), the elastic modulus change rate E _{(23− n)} (%) is determined by 100 × (E ₂₃ −E _n ) / E ₂₃ .

  The tensile elastic modulus was measured with a Rheovibron DDV-II-EP1 manufactured by Orientec using a 15 mm (width) × 10 mm (length) measurement film made of the same material as the film or sheet constituting the substrate. A value measured at a frequency of 11 Hz. In this specification, it measures about 10 or more samples, and evaluates by the average value of the obtained tensile elasticity modulus.

The substrate of the present invention, the tensile modulus _{(E 23)} and the tensile modulus at ₆₀ ℃ _(E 60) because sought modulus change rate _{E (23-60)} preferably at 23 ° C. is 30% or less .

The elastic modulus change rate E _(23-60) is one of the indicators of the deformability of the substrate at 60 ° C., and the lower the value, the more the deformation is suppressed. Therefore, a base material having an elastic modulus change rate E _(23-60) of 30% or less undergoes very little thermal deformation at 60 ° C. Polyvinyl chloride, which is _widely used as a base material for adhesive tapes, has an elastic modulus change rate E _(23-60) of about 95%, and an ethylene / methacrylic acid copolymer has about 70%.

When the elastic modulus change rate E _(23-60) is 30% or less, deformation is suppressed even when the adhesive tape is heated to around 60 ° C. during dry polishing, and chip peeling at the end of the adhesive tape is reduced. . Although not theoretically constrained at all, the mechanism of the manifestation of such an effect is estimated as follows. The substrate may be deformed by the heating of the substrate during dry polishing and the shearing force applied to the chip during polishing. In particular, when the elastic modulus of the base material decreases due to heating, it becomes susceptible to deformation, which may cause unpredictable deformation. However, if the elastic modulus change rate E _(23-60) is 30% or less, the characteristics at normal temperature are almost maintained, and it is considered that deformation due to temperature change is also suppressed. On the other hand, if the elastic modulus change rate E _(23-60) exceeds 30%, the base material may change greatly from the characteristics at room temperature due to heating of the base material, and may cause unexpected deformation. As a result, the adhesive tape curls due to thermal deformation, and many product chips and excess area chips peel off and drop off, leading to a decrease in yield, and the peeled chips come into contact with other chips and other chips. May be damaged, the grinding apparatus may be damaged, or a conveyance failure to the next process may be caused.

The lower the elastic modulus change rate E _(23-60) , the better the result, and further preferably 25% or less, and more preferably 20% or less. The lower limit is not particularly limited, but is 3% or more from the viewpoint of obtaining materials.

Furthermore, the tensile elastic modulus (E ₂₃ ) at 23 ° C. of the substrate is preferably 200 to 2000 MPa, and more preferably 350 to 1500 MPa. Polyvinyl chloride, which is widely used as a base material for adhesive tapes, has a tensile modulus (E ₂₃ ) of about 450 MPa, and an ethylene / methacrylic acid copolymer has about 110 MPa.

Furthermore, the tensile elastic modulus (E ₆₀ ) at 60 ° C. of the substrate is preferably 150 to 1400 MPa, more preferably 300 to 1200 MPa. Polyvinyl chloride, which is widely used as a base material for pressure-sensitive adhesive tapes, has a tensile modulus (E ₆₀ ) of about 22 MPa, and an ethylene / methacrylic acid copolymer has a viscosity of about 34 MPa.

(Non-limiting examples)
The substrate of the present invention is not particularly limited as long as the above physical properties are satisfied, and may be resin films or sheets of various materials. Such a substrate can easily select a sheet having desired characteristics by performing TMA measurement on various resin sheets, and further measuring dimensional change rate and elastic modulus as necessary. Although an example of the base material of the present invention is described in detail below, these are merely descriptions for facilitating the acquisition of the base material and should not be construed as limiting in any way.

   The base material of the present invention may be a laminate of, for example, a first base material made of a relatively hard resin film and a second base material made of a relatively soft resin film. By using a laminate of resin films having different properties, the control of properties becomes easy, and a substrate having desired properties can be easily obtained. Further, the base material of the present invention may be a laminate composed of two layers of a first base material and a second base material, and the same or different second base materials are provided on both surfaces of the first base material. A laminated body having a three-layer structure may be used.

(First base material)
The first base material is preferably a rigid film having a Young's modulus of 1000 MPa or more, more preferably 1800 to 30000 MPa, and further preferably 2500 to 6000 MPa.
When a rigid film with a high Young's modulus is used as a constituent layer of the base material, the holding performance of the adhesive tape on the semiconductor wafer or semiconductor chip is enhanced, and the chipping or breakage of the semiconductor chip is prevented by suppressing vibration during back grinding. It becomes easy to do. Moreover, when the Young's modulus is in the above range, it is possible to reduce the stress when the adhesive tape is peeled from the semiconductor chip, and it is easy to prevent chip chipping or breakage that occurs when the tape is peeled. Furthermore, it is possible to improve the workability when attaching the adhesive tape to the semiconductor wafer.

Here, as a rigid film having a Young's modulus of 1000 MPa or more, for example, polyesters such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, wholly aromatic polyester, polyimide, polyamide, polycarbonate, polyacetal, modified polyphenylene oxide, polyphenylene sulfide, polysulfone And films of polyetherketone, biaxially oriented polypropylene, and the like.
Among these resin films, a film containing at least one selected from a polyester film, a polyamide film, a polyimide film, and a biaxially stretched polypropylene film is preferable, a polyester film is more preferable, and a polyethylene terephthalate film is further preferable. .

  The thickness (D1) of the first base material is preferably 500 μm or less, more preferably 15 to 350 μm, still more preferably 20 to 160 μm. By making the thickness of the first base material 500 μm or less, it becomes easy to adjust the peeling force of the adhesive tape to the above-described predetermined value. Moreover, by setting it as 15 micrometers or more, it becomes easy for a base material to fulfill | perform the function as a support body of an adhesive tape.

In addition, the first base material contains a plasticizer, a lubricant, an infrared absorber, an ultraviolet absorber, a filler, a colorant, an antistatic agent, an antioxidant, a catalyst, and the like as long as the effects of the present invention are not impaired. May be. Further, the first base material may be transparent or opaque, and may be colored or vapor-deposited as desired.
Further, at least one surface of the first base material may be subjected to an adhesive treatment such as a corona treatment in order to improve the adhesion with at least one of the second base material and the pressure-sensitive adhesive layer. Moreover, the 1st base material may have an above-described resin film and the easily bonding layer coat | covered on the at least one surface of the resin film.

Although it does not specifically limit as a composition for easy-adhesion layer formation which forms an easy-adhesion layer, For example, the composition containing a polyester-type resin, a urethane-type resin, a polyester urethane-type resin, an acrylic resin etc. is mentioned. The easy-adhesion layer forming composition may contain a crosslinking agent, a photopolymerization initiator, an antioxidant, a softening agent (plasticizer), a filler, an antirust agent, 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. In addition, since the thickness of an easily bonding layer is small with respect to the thickness of a 1st base material, and a material is also soft, the influence which has on a Young's modulus is small, and the Young's modulus of a 1st base material has an easily bonding layer. However, it is substantially the same as the Young's modulus of the resin film.

(Second base material)
A 2nd base material consists of a comparatively soft resin film, the vibration by grinding of a semiconductor wafer is relieve | moderated, and it prevents that a crack and a chip | tip arise in a semiconductor wafer. In addition, the semiconductor wafer to which the adhesive tape is attached is placed on the suction table at the time of back surface grinding, but the adhesive tape is provided with a second base material, so that retention on the suction table is improved and after the back surface grinding. The peelability from the suction table is imparted.
The second base material preferably has a storage elastic modulus at 23 ° C. of 100 to 1500 MPa, and more preferably 200 to 1200 MPa. Moreover, 70-100% is preferable and, as for the stress relaxation rate of a 2nd base material, it is more preferable that it is 78-98%.

Since the second base material has an elastic modulus and stress relaxation rate within the above ranges, the unevenness of fine foreign matter sandwiched between the adhesive tape and the suction table, and the vibration and impact of the grindstone that occurs during back surface grinding. The effect which a 2nd base material absorbs becomes high.
The ratio (D2 / D1) of the thickness (D2) of the second substrate to the thickness (D1) of the first substrate is preferably 0.7 or less. If the thickness ratio (D2 / D1) is greater than 0.7, the ratio of the highly rigid portion in the adhesive tape decreases, so that the semiconductor wafer and the semiconductor chip are not easily held by the base material and are ground. The vibration at the time becomes difficult to reduce. Therefore, in the case of dividing into small and thin semiconductor chips by the tip dicing method, the semiconductor generated when dividing into pieces by back grinding even if an appropriate material is selected as the second base material Chip chipping is difficult to prevent.
The thickness ratio (D2 / D1) may be 0.10 to 0.70 in order to reduce the chip breakage and improve the buffer performance of the adhesive tape by setting the second substrate to an appropriate thickness. preferable.

The maximum value of tan δ of dynamic viscoelasticity at −5 to 120 ° C. of the second base material (hereinafter also simply referred to as “maximum value of tan δ”) is preferably 0.7 or more, more preferably 0.8 or more. More preferably, it is 1.0 or more. The upper limit of the maximum value of tan δ is not particularly limited, but is usually 2.0 or less.
If the maximum value of tan δ of the second base material is 0.7 or more, the effect of the second base material absorbing the vibration and impact of the grindstone that occurs during back grinding is enhanced. Therefore, in the tip dicing method, even if the semiconductor wafer or the separated semiconductor chip is ground until it becomes extremely thin, chipping at the corners of the chip can be easily prevented.
Note that tan δ is called loss tangent and is defined as “loss elastic modulus / storage elastic modulus”, and is a value measured by a response to a stress such as tensile stress or torsional stress applied to an object by a dynamic viscoelasticity measuring apparatus. It is.

  The thickness (D2) of the second base material is preferably 8 to 80 μm, and more preferably 10 to 60 μm. By setting the thickness of the second base material to 8 μm or more, the second base material can appropriately buffer vibration during back surface grinding. Moreover, it becomes easy to adjust thickness ratio (D2 / D1) to said value because it is 80 micrometers or less. When the base material is a three-layer structure in which the same or different second base materials are stacked on both sides of the first base material, the thickness (D2) of the second base material is preferably 35 μm. Or less, more preferably 30 μm or less. In a laminate having a three-layer structure, the physical properties of the relatively soft second base material may be dominant, but by setting the thickness of the second base material within the above range, a desired 60 ° C. TMA value, It becomes easy to adjust the dimensional change rate.

The second substrate may be formed from a soft film such as low-density polyethylene, but is preferably a layer formed from a second substrate-forming composition containing an energy beam polymerizable compound. Since the second base material contains the energy ray polymerizable compound, the second base material can be cured by being irradiated with the energy rays. “Energy rays” refer to ultraviolet rays, electron beams, and the like, and preferably ultraviolet rays are used.
More specifically, the second substrate-forming composition is a urethane (meth) acrylate (a1), a polymerizable compound (a2) having an alicyclic group or heterocyclic group having 6 to 20 ring atoms. It is preferable to contain. By containing these two components, the composition for forming the second base material easily makes the elastic modulus of the second base material, the stress relaxation rate of the second base material, and the maximum value of tan δ within the above-described ranges. Moreover, it is more preferable that the composition for 2nd base material formation contains the polymeric compound (a3) which has a functional group in addition to the said (a1) and (a2) component from these viewpoints.
In addition to the above components (a1) and (a2) or (a1) to (a3), the second substrate-forming composition further preferably contains a photopolymerization initiator, and the effects of the present invention can be obtained. Other additives and resin components may be contained as long as they are not impaired.
Hereafter, each component contained in the composition for 2nd base material formation is demonstrated 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 irradiation with energy rays. Urethane (meth) acrylate (a1) is an oligomer or a polymer.

The mass 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. “Mass average molecular weight (Mw)” is a polystyrene equivalent value measured by gel permeation chromatography (GPC), and is specifically measured under the following conditions.
(Measurement condition)
・ Column: “TSK guard column HXL-H” “TSK gel GMHXL (× 2)” “TSK gel G2000HXL” (both manufactured by Tosoh Corporation)
-Column temperature: 40 ° C
・ Developing solvent: Tetrahydrofuran ・ Flow rate: 1.0 mL / min
Further, the number of (meth) acryloyl groups (hereinafter also referred to as “number of functional groups”) in the component (a1) may be monofunctional, bifunctional, or trifunctional or more, but is preferably monofunctional or bifunctional. .
The component (a1) can be obtained, for example, by reacting a (meth) acrylate having a hydroxyl group with a terminal isocyanate urethane prepolymer obtained by reacting a polyol compound and a polyvalent isocyanate compound. In addition, you may use a component (a1) 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 is a compound having two or more hydroxy groups. Specific examples of the polyol compound include alkylene diol, polyether type polyol, polyester type polyol, and polycarbonate type polyol. Among these, a polyester type polyol is preferable.
The polyol compound may be a bifunctional diol, a trifunctional triol, or a tetrafunctional or higher polyol, but is preferably a bifunctional diol, and more preferably a polyester type diol.

Examples of the polyvalent isocyanate compound include aliphatic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate; isophorone diisocyanate, norbornane diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, and dicyclohexylmethane-2. , 4′-diisocyanate, ω, ω′-diisocyanate dimethylcyclohexane, and the like; 4,4′-diphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, tolidine diisocyanate, tetramethylene xylylene diisocyanate, naphthalene- And 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 the terminal isocyanate urethane prepolymer obtained by reacting the above-described polyol compound with the polyvalent isocyanate compound with (meth) acrylate having a hydroxy group. 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.

Specific 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-hydroxycyclooctyl (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, pentaerythritol tri (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, etc. Hydroxyalkyl (meth) acrylates; hydroxy group-containing (meth) acrylamides such as N-methylol (meth) acrylamide; vinyl alcohol, vinyl phenol, bisphenol The reaction product obtained by the diglycidyl ester of Nord A (meth) acrylic acid is reacted, and the like.
Among these, hydroxyalkyl (meth) acrylate is preferable, and 2-hydroxyethyl (meth) acrylate is more preferable.

The conditions for reacting the terminal isocyanate urethane prepolymer and the (meth) acrylate having a hydroxy group are preferably 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. .
The content of the component (a1) in the second substrate-forming composition is preferably 10 to 70% by mass, more preferably 20 with respect to the total amount (100% by mass) of the second substrate-forming composition. -60 mass%, More preferably, it is 25-55 mass%, More preferably, it is 30-50 mass%.

(Polymerizable compound (a2) having an alicyclic group or heterocyclic group having 6 to 20 ring atoms)
Component (a2) is a polymerizable compound having an alicyclic group or heterocyclic group having 6 to 20 ring atoms, and is preferably a compound having at least one (meth) acryloyl group. By using this component (a2), the film formability of the obtained composition for forming a second substrate can be improved.

The number of ring-forming atoms of the alicyclic group or heterocyclic group contained in the component (a2) is preferably 6 to 20, more preferably 6 to 18, still more preferably 6 to 16, and particularly preferably 7 to 12. is there. Examples of the atoms forming the ring structure of the heterocyclic group include a carbon atom, a nitrogen atom, an oxygen atom, and a sulfur atom.
The number of ring-forming atoms means the number of atoms constituting the ring itself of a compound having a structure in which atoms are bonded in a ring, and atoms that do not form a ring (for example, hydrogen atoms bonded to atoms forming the ring) In addition, an atom included in a substituent when the ring is substituted with a substituent is not included in the number of ring-forming atoms.

Specific components (a2) include, for example, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyloxy (meth) acrylate, cyclohexyl (meth) acrylate, And alicyclic group-containing (meth) acrylates such as adamantane (meth) acrylate; heterocyclic group-containing (meth) acrylates such as tetrahydrofurfuryl (meth) acrylate and morpholine (meth) acrylate;
In addition, you may use a component (a2) individually or in combination of 2 or more types.
Among these, alicyclic group-containing (meth) acrylate is preferable, and isobornyl (meth) acrylate is more preferable.

  The content of the component (a2) in the second substrate-forming composition is preferably 10 to 70% by mass, more preferably 20 with respect to the total amount (100% by mass) of the second substrate-forming composition. It is -60 mass%, More preferably, it is 25-55 mass%, Most preferably, it is 30-50 mass%.

(Polymerizable compound having functional group (a3))
Component (a3) is a polymerizable compound containing a functional group such as a hydroxyl group, an epoxy group, an amide group, or an amino group, and more preferably a compound having at least one (meth) acryloyl group.
The component (a3) has good compatibility with the component (a1), and it is easy to adjust the viscosity of the second substrate-forming composition to an appropriate range. In addition, the elastic modulus and tan δ of the second base material formed from the composition can be easily set in the above-described range, and the buffer performance is improved even if the second base material is relatively thin.
Examples of the component (a3) 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 include butyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and phenylhydroxypropyl (meth) acrylate.
Examples of the epoxy group-containing compound include glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, and allyl glycidyl ether. Among these, epoxy such as glycidyl (meth) acrylate and methyl glycidyl (meth) acrylate is used. Group-containing (meth) acrylates are preferred.
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, N -Methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, etc. are mentioned.
Examples of amino group-containing (meth) acrylates include primary amino group-containing (meth) acrylates, secondary amino group-containing (meth) acrylates, and tertiary amino group-containing (meth) acrylates.

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.
In addition, you may use a component (a3) individually or in combination of 2 or more types.

The content of the component (a3) in the second substrate-forming composition makes it easy to bring the elastic modulus and stress relaxation rate of the second substrate into the above-mentioned ranges, and the composition of the second substrate-forming composition. In order to improve the film property, the amount is preferably 5 to 40% by mass, more preferably 7 to 35% by mass, and still more preferably 10 to 30% with respect to the total amount (100% by mass) of the second substrate forming composition. % By mass, particularly preferably 13 to 25% by mass.
Further, the content ratio [(a2) / (a3)] of the component (a2) and the component (a3) in the second substrate forming composition is preferably 0.5 to 3.0, more preferably It is 1.0-3.0, More preferably, it is 1.3-3.0, Most preferably, it is 1.5-2.8.

(Polymerizable compounds other than components (a1) to (a3))
The composition for forming a second substrate may contain other polymerizable compound other than the components (a1) to (a3) as long as the effects of the present invention are not impaired.
Examples of other polymerizable compounds 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. Vinyl compounds such as: and the like. In addition, you may use these other polymeric compounds individually or in combination of 2 or more types.

  The content of the other polymerizable compound in the second substrate-forming composition 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. It is -2 mass%.

(Photopolymerization initiator)
When forming the second substrate, the second substrate-forming composition may further contain a photopolymerization initiator from the viewpoint of shortening the polymerization time due to light irradiation and reducing the amount of light irradiation. preferable.
Examples of the photopolymerization initiator include benzoin compounds, acetophenone compounds, acyl phosphinoxide compounds, titanocene compounds, thioxanthone compounds, peroxide compounds, and photosensitizers such as amines and quinones. Specifically, for example, 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, diacetyl, 8-chloroanthraquinone, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, etc. It is.
These photopolymerization initiators can be used alone or in combination of two or more.
The content of the photopolymerization initiator in the second substrate forming composition is preferably 0.05 to 15 parts by mass, more preferably 0.1 to 100 parts by mass of the total amount of the energy beam polymerizable compound. -10 parts by mass, more preferably 0.3-5 parts by mass.

(Other additives)
The composition for forming a second substrate 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, and dyes. When blending these additives, the content of each additive in the second substrate forming composition is preferably 0.01 to 6 masses with respect to 100 mass parts of the total amount of the energy beam polymerizable compound. Part, more preferably 0.1 to 3 parts by weight.

(Resin component)
The composition for forming a second substrate 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 resins, polyolefin resins such as polybutene, polybutadiene, and polymethylpentene, and thermoplastic resins such as styrene copolymers.
The content of these resin components in the second substrate-forming composition 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 0% by mass. 2% by mass.
(Preparation of base material)
A non-limiting example of the base material of the pressure-sensitive adhesive tape of the present invention is a laminate of the first base material and the second base material. There is no restriction | limiting in particular as a manufacturing method, It can manufacture by a well-known method.
For example, the second base material formed by applying and curing the second base material-forming composition on the release sheet and the first base material are directly bonded together, and the release sheet is removed, whereby the laminated base material is obtained. Is obtained.
As a method of forming the second substrate on the release sheet, the second substrate-forming composition is directly applied on the release sheet by a known coating method to form a coating film. A 2nd base material can be formed by irradiating an energy ray. Alternatively, the second base material may be formed by directly applying the second base material forming composition to one surface of the first base material and irradiating the coating film with energy rays.

  Examples of the method for applying the second substrate-forming composition include spin coating, spray coating, bar coating, knife coating, roll coating, blade coating, die coating, and gravure coating. . Moreover, in order to improve applicability | paintability, an organic solvent may be mix | blended with respect to the composition for 2nd base material formation, and it may apply | coat on a peeling sheet as a form of a solution.

  When the composition for forming the second base material contains an energy beam polymerizable compound, the coating film of the composition for forming the second base material is cured by irradiating the energy beam to form the second base material. It is preferable. The second substrate may be cured by a single curing process, or may be performed in multiple steps. For example, after the coating film on the release sheet is completely cured to form the second substrate, it may be bonded to the first substrate, and the second film in a semi-cured state without completely curing the coating film. After the base material forming film is formed and the second base material forming film is bonded to the first base material, the second base material may be formed by irradiating energy rays again to be completely cured. As an energy ray irradiated by the said hardening process, an ultraviolet-ray is preferable. When curing, the coating film of the second substrate forming composition may be exposed, but the coating film is covered with the release sheet or the first substrate, and the energy beam is not exposed. It is preferable to cure by irradiation.

  Furthermore, the base material can be obtained by laminating the second base material on one side or both sides of the first base material. Moreover, the base material of the present invention may have other constituent layers as long as a predetermined 60 ° C. TMA value is satisfied in addition to the first base material and the second base material.

The total thickness of the base material is the total thickness of the first base material, the second base material, and other constituent layers that may be used as necessary, and is preferably 23 to 150 μm, more preferably 30 to 140 μm.
The laminated base material as an example of the base material of the present invention is a laminated body of a first base material and a second base material, and its physical properties are controlled by the materials and thicknesses of the first base material and the second base material. it can. Therefore, in order to obtain a substrate having desired characteristics, it is important to balance the characteristics of the first substrate and the second substrate in accordance with the following guidelines.

  The 60 ° C. TMA value, the dimensional change rate, and the elastic modulus change rate of the substrate can be controlled by appropriately selecting a film constituting the substrate. For example, these values can be lowered by annealing a film having a relatively high Tg as a constituent film or when forming a substrate. Similarly, when the base material is a laminated base material of the first base material and the second base material, the first base material or the second base material, or both of them, a high Tg film or an annealed film. By configuring this, the 60 ° C. TMA value, the dimensional change rate, and the elastic modulus change rate can be controlled in a low range. Furthermore, in the case of a laminated substrate, the 60 ° C. TMA value, the dimensional change rate, and the elastic modulus change rate can be controlled in a low range by increasing the relative thickness of the high Tg film or the annealed film. . Moreover, when using another structural layer, when a film with relatively high rigidity is used, the 60 ° C. TMA value, the dimensional change rate, and the elastic modulus change rate can be controlled within a low range.

[Adhesive layer]
The pressure-sensitive adhesive is not particularly limited as long as it has an appropriate pressure-sensitive adhesive property at room temperature, but preferably has a storage elastic modulus at 23 ° C. of 0.05 to 0.50 MPa. A circuit or the like is formed on the surface of the semiconductor wafer and is usually uneven. The pressure-sensitive adhesive tape has a storage elastic modulus within the above range, so that when the adhesive surface is applied to a wafer surface with unevenness, the unevenness of the wafer surface and the pressure-sensitive adhesive layer are sufficiently brought into contact with each other, and the adhesiveness of the pressure-sensitive adhesive layer is improved. It is possible to make it work properly. Therefore, it becomes possible to securely fix the adhesive tape to the semiconductor wafer and to appropriately protect the wafer surface during back grinding. From these viewpoints, the storage elastic modulus of the pressure-sensitive adhesive is more preferably 0.10 to 0.35 MPa. In addition, the storage elastic modulus of an adhesive means the storage elastic modulus before hardening by energy ray irradiation, when an adhesive layer is formed from an energy ray-curable adhesive.

  The thickness (D3) of the pressure-sensitive adhesive layer is preferably less than 200 μm, more preferably 5 to 55 μm, and still more preferably 10 to 50 μm. When the pressure-sensitive adhesive layer is thinned in this way, the ratio of the low-rigidity portion of the pressure-sensitive adhesive tape can be reduced, so that it becomes easier to prevent chipping of the semiconductor chip that occurs during back surface 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, etc., and an acrylic pressure-sensitive adhesive is preferable.
Moreover, it is preferable that an adhesive layer is formed from an energy-beam curable adhesive. The pressure-sensitive adhesive layer is formed from an energy-ray curable pressure-sensitive adhesive, so that the elastic modulus at 23 ° C. is set within the above range before curing by irradiation with energy rays, and the peeling force is 1000 mN / 50 mm after curing. It can be easily set as follows.

Hereinafter, although the specific example of an adhesive is explained in full detail, these are non-limiting illustrations, The adhesive layer in this invention should not be limitedly limited to these.
Examples of the energy ray curable adhesive include an energy ray curable adhesive containing an energy ray curable compound other than an 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. In addition, as an energy ray curable adhesive, an energy ray curable adhesive resin having an unsaturated group introduced into the side chain of a non-energy ray curable adhesive resin (hereinafter also referred to as “adhesive resin II”). An adhesive composition that is contained as a main component and does not contain an energy ray curable compound other than an adhesive resin (hereinafter also referred to as “Y-type adhesive composition”) may be used.

Furthermore, as the energy ray curable pressure sensitive adhesive, an X ray and Y type combined type, that is, an energy ray curable compound containing an energy ray curable compound other than the adhesive resin in addition to the energy ray curable adhesive resin II. An adhesive composition (hereinafter, also referred to as “XY-type adhesive composition”) may be used.
Among these, it is preferable to use an XY type pressure-sensitive adhesive composition. By using the XY type, it is possible to sufficiently reduce the peeling force on the semiconductor wafer after curing while having sufficient adhesive properties before curing.

  However, the pressure-sensitive adhesive may be formed from a non-energy ray-curable pressure-sensitive adhesive composition that does not cure even when irradiated with energy. The non-energy ray curable adhesive composition contains at least the non-energy ray curable adhesive resin I, but does not contain the energy ray curable adhesive resin II and the energy ray curable compound described above. is there.

In the following description, “adhesive resin” is used as a term indicating one or both of the above-described adhesive resin I and adhesive resin II. Specific examples of the adhesive resin include acrylic resins, urethane resins, rubber resins, and silicone resins. Acrylic resins are preferable.
Hereinafter, the acrylic adhesive in which an acrylic resin is used as the adhesive resin will be described in more detail.

  An acrylic polymer (b) is used for the acrylic resin. The acrylic polymer (b) is obtained by polymerizing a monomer containing at least an alkyl (meth) acrylate, and includes 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 the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) methacrylate, 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. Alkyl (meth) acrylates may be used alone or in combination of two or more.

  Moreover, it is preferable that an acrylic polymer (b) contains the structural unit derived from the alkyl (meth) acrylate whose carbon number of an alkyl group is 4 or more from a viewpoint of improving the adhesive force of an adhesive layer. As carbon number of this alkyl (meth) acrylate, Preferably it is 4-12, More preferably, it is 4-6. Moreover, it is preferable that the alkyl (meth) acrylate whose carbon number of an alkyl group is 4 or more is an alkyl acrylate.

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

  In order to adjust the elastic modulus and adhesive properties of the pressure-sensitive adhesive layer in addition to the structural unit derived from alkyl (meth) acrylate having an alkyl group with 4 or more carbon atoms, the acrylic polymer (b) A copolymer containing a structural unit derived from an alkyl (meth) acrylate having 1 to 3 carbon atoms is preferred. 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 1 to 3 carbon atoms in the alkyl group is preferably 1 to 30% by mass, more preferably 3 to 26% by mass, based on the total amount of monomers. More preferably, it is 6-22 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 alkyl (meth) acrylate. Examples of the functional group of the functional group-containing monomer include a hydroxyl group, a carboxy group, an amino group, and an epoxy group. The functional group-containing monomer reacts with a crosslinking agent described later to become a crosslinking 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, 3-hydroxybutyl (meta ) Hydroxyalkyl (meth) acrylates such as acrylate and 4-hydroxybutyl (meth) acrylate; Unsaturated alcohols such as vinyl alcohol and allyl alcohol.

  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 anhydrides thereof. , 2-carboxyethyl methacrylate and the like.

The functional group monomer is preferably 1 to 35% by mass, more preferably 3 to 32% by mass, and still more preferably 6 to 30% by mass with respect to the total amount of 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, vinyl toluene, vinyl formate, vinyl acetate, acrylonitrile, acrylamide and the like. A structural unit may be included.

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

An unsaturated group containing compound is a compound which has both the substituent which can be couple | bonded with the functional group of an acrylic polymer (b), and a photopolymerizable unsaturated group. Examples of the photopolymerizable unsaturated group include a (meth) acryloyl group, a vinyl group, and an allyl group, and a (meth) acryloyl group is preferable.
Examples of the substituent that the unsaturated group-containing compound can bind to the functional group include an isocyanate group and a glycidyl group. Therefore, examples of the unsaturated group-containing compound include (meth) acryloyloxyethyl isocyanate, (meth) acryloyl isocyanate, glycidyl (meth) acrylate, and the like.

Moreover, it is preferable that an unsaturated group containing compound reacts with a part of functional group of an acrylic polymer (b), and specifically, 50-98 mol of functional groups which an acrylic polymer (b) has. % 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 it is easily cross-linked by the cross-linking agent.
In addition, the weight average molecular weight (Mw) of acrylic resin becomes like this. Preferably it is 300,000-1,600,000, More preferably, it is 400,000-1,400,000, More preferably, it is 500,000-1,200,000.

(Energy ray curable compound)
The energy ray-curable compound contained in the X-type or XY-type pressure-sensitive adhesive composition is preferably a monomer or oligomer having an unsaturated group in the molecule and capable of being polymerized and cured by irradiation with energy rays.
Examples of such energy ray curable compounds include trimethylolpropane tri (meth) acrylate, pentaerythritol (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 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 ( And oligomers such as (meth) acrylate.

Among these, urethane (meth) acrylate oligomers are preferable from the viewpoint of relatively high molecular weight and difficulty in reducing the 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 10,000, 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 still more preferably 60 to 100 parts by mass with respect to 100 parts by mass of the adhesive resin. 90 parts by mass.
On the other hand, the content of the energy ray-curable compound in the XY pressure-sensitive adhesive composition is preferably 1 to 30 parts by mass, more preferably 2 to 20 parts by mass, and still more preferably, with respect to 100 parts by mass of the adhesive resin. Is 3 to 15 parts by mass. In the XY-type pressure-sensitive adhesive composition, the adhesive resin is energy ray curable, so even if the content of the energy ray curable compound is small, it is possible to sufficiently reduce the peeling force after irradiation with energy rays. It is.

(Crosslinking agent)
The pressure-sensitive adhesive composition preferably further contains a crosslinking agent. A crosslinking agent reacts with the functional group derived from the functional group monomer which adhesive resin has, for example, and bridge | crosslinks adhesive resins. Examples of the crosslinking agent include isocyanate-based crosslinking agents such as tolylene diisocyanate, hexamethylene diisocyanate, and adducts thereof; ethylene glycol glycidyl ether, 1,3-bis (N, N′-diglycidylaminomethyl) cyclohexane An epoxy-based cross-linking agent such as hexa [1- (2-methyl) -aziridinyl] triphosphatriazine or the like; an aziridine-based cross-linking agent such as aluminum chelate; These crosslinking agents may be used alone or in combination of two or more.

Among these, an isocyanate-based crosslinking agent is preferable from the viewpoints of increasing cohesive force and improving adhesive force, and availability.
From the viewpoint of promoting the crosslinking reaction, the amount of the crosslinking agent is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 7 parts by mass, and still more preferably 0 with respect to 100 parts by mass of the adhesive resin. 0.05 to 4 parts by mass.

(Photopolymerization initiator)
Moreover, when an adhesive composition is energy-beam curable, it is preferable that an adhesive composition contains a photoinitiator further. By containing the photopolymerization initiator, the curing reaction of the pressure-sensitive adhesive composition can sufficiently proceed even with relatively low energy energy rays such as ultraviolet rays.

  Examples of the photopolymerization initiator include benzoin compounds, acetophenone compounds, acylphosphinoxide compounds, titanocene compounds, thioxanthone compounds, peroxide compounds, and photosensitizers such as amines and quinones. Specifically, for example, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzylphenyl Examples include sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, dibenzyl, diacetyl, 8-chloroanthraquinone, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide. It is.

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 still more preferably 0.05 to 5 parts by mass with respect to 100 parts by mass of the adhesive resin. It 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, tackifiers, softeners (plasticizers), fillers, rust inhibitors, pigments, dyes, and the like. When mix | blending these additives, the compounding quantity of an additive becomes like this. Preferably it is 0.01-6 mass parts with respect to 100 mass parts of adhesive resins.

Further, the pressure-sensitive adhesive composition may be further diluted with an organic solvent from the viewpoint of improving applicability to a substrate or a release sheet, and may be in the form of a solution of the pressure-sensitive adhesive composition.
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 the synthesis of the 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 may be added.

[Peeling 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 pressure-sensitive adhesive tape. The release sheet is attached to the surface of the pressure-sensitive adhesive layer to protect the pressure-sensitive adhesive layer during transportation and storage. The release sheet is detachably attached to the adhesive tape, and is peeled off and removed from the adhesive tape before the adhesive tape is used (that is, before grinding the wafer back surface).
As the release sheet, a release sheet having at least one surface subjected to a release treatment is used, and specifically, a release sheet coated on the surface of the release sheet substrate may be used.

As the base for the release sheet, a resin film is preferable, and examples of the resin constituting the resin film include polyester resin films such as polyethylene terephthalate resin, polybutylene terephthalate resin, and polyethylene naphthalate resin, polypropylene resin, polyethylene resin, and the like. Polyolefin resin and the like. Examples of the release agent include rubber elastomers such as silicone resins, olefin resins, isoprene resins, and butadiene resins, long chain alkyl resins, alkyd resins, and fluorine resins.
Although there is no restriction | limiting in particular in the thickness of a peeling sheet, Preferably it is 10-200 micrometers, More preferably, it is 20-150 micrometers.

(Manufacturing method of adhesive tape)
There is no restriction | limiting in particular as a manufacturing method of the adhesive tape of this invention, It can manufacture by a well-known method.
For example, an adhesive tape provided on a release sheet can be bonded to one side of a substrate, and an adhesive tape having a release sheet attached to the surface of the adhesive layer can be produced. The release sheet attached to the surface of the pressure-sensitive adhesive layer may be appropriately peeled and removed before using the pressure-sensitive adhesive tape.
As a method of forming the pressure-sensitive adhesive layer on the release sheet, the pressure-sensitive adhesive composition is directly applied on the release sheet by a known coating method, and is heated and dried to volatilize the solvent from the coating film. An agent layer can be formed.

  Moreover, you may apply | coat an adhesive (adhesive composition) directly to the single side | surface of a base material, and may form an adhesive layer. As the method for applying the adhesive, the spin coating method, spray coating method, bar coating method, knife coating method, roll coating method, blade coating method, die coating method, gravure coating method, etc., shown in the second substrate production method Is mentioned.

  The pressure-sensitive adhesive layer may be provided on the surface of the first base material that constitutes the base material, or may be provided on the surface of the second base material. It is preferable to provide on the surface of a 1st base material. When the pressure-sensitive adhesive layer is provided on the first base material surface, the second base material side is arranged on the suction table used during back surface grinding. Since the second base material is relatively soft, it can easily adhere to the suction table and can prevent the adhesive tape from curling.

[Method for Manufacturing Semiconductor Device]
The pressure-sensitive adhesive tape of the present invention is particularly preferably used when the wafer is ground on the back surface of the semiconductor wafer by the tip dicing method. As a non-limiting use example of the adhesive tape, a method for manufacturing a semiconductor device will be described more specifically below.

Specifically, the semiconductor device manufacturing method includes at least the following steps 1 to 4.
Step 1: Step of forming grooves from the surface side of the semiconductor wafer Step 2: Step of applying the above-mentioned adhesive tape to the surface of the semiconductor wafer Step 3: Semiconductor having the adhesive tape attached to the surface and the above-mentioned grooves formed Grinding the wafer from the back side, removing the bottom of the groove, and dividing into a plurality of chips Step 4: The adhesive tape is separated from the separated semiconductor wafers (that is, a plurality of semiconductor chips). Peeling process

Hereafter, each process of the manufacturing method of the said semiconductor device is demonstrated in detail.
(Process 1)
In step 1, a groove is formed from the surface side of the semiconductor wafer.
The groove formed in this step is a groove having a depth shallower than the thickness of the semiconductor wafer. The groove can be formed by dicing using a conventionally known wafer dicing apparatus or the like. Further, the semiconductor wafer is divided into a plurality of semiconductor chips along the groove by removing the bottom of the groove in step 3 described later.
(Process 2)
In step 2, the pressure-sensitive adhesive tape of the present invention is attached to the surface of the semiconductor wafer on which the grooves are formed via a pressure-sensitive adhesive layer.

  The semiconductor wafer used in this manufacturing method may be a silicon wafer, a gallium / arsenic wafer, a glass wafer, or a sapphire wafer. Although the thickness before grinding of a semiconductor wafer is not specifically limited, Usually, it is about 500-1000 micrometers. A semiconductor wafer usually has a circuit formed on the surface thereof. Formation of a circuit on the wafer surface can be performed by various methods including conventionally used methods such as an etching method, a lift-off method, and a blade method.

  The semiconductor wafer to which the adhesive tape is attached and the groove is formed is placed on the suction table, and is sucked and held on the suction table. At this time, the surface of the semiconductor wafer is adsorbed by being arranged on the table side.

(Process 3)
After step 1 and step 2, the back surface of the semiconductor wafer on the suction table is ground to separate the semiconductor wafer into a plurality of semiconductor chips.
Here, when the groove is formed in the semiconductor wafer, the back surface grinding is performed so that the semiconductor wafer is thinned at least to a position reaching the bottom of the groove. By this back surface grinding, the groove becomes a notch penetrating the wafer, and the semiconductor wafer is divided by the notch and separated into individual semiconductor chips.

The shape of the separated semiconductor chip may be a square or may be an elongated shape such as a rectangle. The thickness of the separated semiconductor chip is not particularly limited, but is preferably about 5 to 100 μm, more preferably 10 to 45 μm. The size of the individual semiconductor chip is not particularly limited, but the chip size is preferably less than 50 mm ² , more preferably less than 30 mm ² , and even more preferably less than 10 mm ² .

When the adhesive tape of the present invention is used, even in such a thin and / or small semiconductor chip, chipping occurs in the semiconductor chip during back grinding (step 3) and when the adhesive tape is peeled off (step 4). Is prevented.
After the back surface grinding is completed, it is preferable to perform dry polishing prior to chip pickup.

  In back surface grinding, grinding marks remain on the back surface of the chip, and minute chipping (chipping) occurs at the end of the chip, which is a factor that impairs the bending strength of the chip. As a result of thinning and miniaturization of the chip, the chip tends to be damaged, and a reduction in bending strength is regarded as a problem. In order to remove the above-mentioned grinding marks and minute chips (damaged parts) of the chip, after the backside grinding, the damaged part is finally removed by dry polishing that does not use water, thereby improving the bending strength of the chip. It is preferable. Since no water is used during dry polishing, the chips are heated. The heat of the chip propagates to the adhesive tape. As a result, at the time of dry polishing, the temperature of the substrate becomes 60 ° C. or higher, the end of the adhesive tape may curl, and the chip may peel off. However, by using the pressure-sensitive adhesive tape of the present invention, deformation of the pressure-sensitive adhesive tape is suppressed, and chip peeling can be reduced. Therefore, the pressure-sensitive adhesive tape of the present invention is particularly preferably used for holding a semiconductor wafer or chip in a tip dicing method including a dry polishing process.

(Process 4)
Next, the pressure-sensitive adhesive tape for semiconductor processing is peeled from the separated semiconductor wafer (that is, a plurality of semiconductor chips). This step is performed, for example, by the following method.
First, when the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape is formed from an energy ray-curable pressure-sensitive adhesive, the pressure-sensitive adhesive layer is cured by irradiating energy rays. Next, a pick-up tape is affixed to the back side of the separated semiconductor wafer, and the position and orientation are adjusted so that pick-up is possible. At this time, the ring frame disposed on the outer peripheral side of the wafer is also bonded to the pick-up tape, and the outer peripheral edge of the pickup tape is fixed to the ring frame. A wafer and a ring frame may be bonded to the pickup tape at the same time, or may be bonded at different timings. Next, the adhesive tape is peeled off from the plurality of semiconductor chips fixed on the pickup tape.

Thereafter, a plurality of semiconductor chips on the pickup tape are picked up and fixed on a substrate or the like to manufacture a semiconductor device.
In addition, although a pickup tape is not specifically limited, For example, it is comprised by the adhesive sheet provided with the adhesive layer provided in the one surface of the base material and the base material.

  An adhesive tape can be used instead of the pickup tape. The adhesive tape is a laminate of a film adhesive and a release sheet, a laminate of a dicing tape and a film adhesive, and an adhesive layer and a release sheet having the functions of both a dicing tape and a die bonding tape. The dicing die-bonding tape etc. which become. In addition, a film adhesive may be bonded to the back side of the separated semiconductor wafer before the pickup tape is applied. When using a film adhesive, the film adhesive may have the same shape as the wafer.

  When using adhesive tape or when attaching a film adhesive to the back side of a semiconductor wafer that has been singulated before applying the pickup tape, multiple semiconductor chips on the adhesive tape or pickup tape are It is picked up with the adhesive layer divided into the same shape as the chip. And a semiconductor chip is fixed on a board | substrate etc. via an adhesive bond layer, and a semiconductor device is manufactured. The adhesive layer is divided by a laser or an expand.

   As described above, the example of using the adhesive tape of the present invention for the method of separating a semiconductor wafer mainly by the tip dicing method has been described. However, the adhesive tape of the present invention can also be used for normal back surface grinding. Yes, 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-peeling adhesive tapes.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not restrict | limited by these examples.

The measurement method and evaluation method in the present invention are as follows.
[TMA value]
A measurement film of 15 mm width × 10 mm (length) made of the same material as the film or sheet constituting the substrate is prepared. Using a 4000SA manufactured by BRUKER, the elongation or shrinkage of the film for measurement is measured at a load of 2 g and a heating rate of 5 ° C./min (TMA value) to obtain a 60 ° C. TMA value at 60 ° C. Measurement conditions other than the above are set according to the operation manual of the measuring apparatus. Ten samples are measured, and the average value of the obtained TMA values is calculated.
[Dimensional change rate]
A 10 cm × 10 cm measuring film made of the same material as the film or sheet constituting the substrate is prepared. The dimensions of the measurement film are measured values at 23 ° C. The measurement sample is allowed to stand at 60 ° C. for 3 minutes on a heating table. Then, after cooling to room temperature (23 ° C.), the following equation is obtained from the length of one side at 23 ° C. before heating (10 cm: L ₀ ) and the length of the same side at 23 ° C. after heating (L ₁ ). Obtain the rate of dimensional change. Ten samples are measured, and an average value of the obtained dimensional change rates is calculated. In addition, the measured value in the MD direction is used as the measured value.
Dimensional change rate (%) = 100 × (L ₀ −L ₁ ) / L ₀

[Tensile modulus]
A measurement film of 15 mm width × 10 mm (length) made of the same material as the film or sheet constituting the substrate is prepared. Ten samples of tensile elastic modulus of a film for measurement at a frequency of 11 Hz and in a temperature range of -20 to 150 ° C. by a dynamic viscoelastic device (product name “Rheobibron DDV-II-EP1” manufactured by Orientec Co., Ltd.) It was measured.
The average value of the tensile modulus at 23 ° C. is E ₂₃ , the average value of the tensile modulus at 60 ° C. is E _60, and the rate of change E _(23-60) (% )

[Young's modulus of the first substrate]
The Young's modulus of the first substrate was measured at a test speed of 200 mm / min according to JISK-7127 (1999).

[Elastic modulus of second substrate and maximum value of tan δ]
Instead of the first substrate, a release sheet (trade name “SP-PET 381031”, thickness: 38 μm, manufactured by Lintec Corporation) was used, and the thickness of the obtained second substrate was 200 μm, A second test substrate was produced in the same manner as the second substrate of Examples and Comparative Examples described later. After removing the release sheet on the second base material for testing, using a test piece cut to a predetermined size, a dynamic viscoelastic device (Orientec Co., Ltd., trade name “Rheobibron DDV-II-EP1”) Thus, the loss elastic modulus and the storage elastic modulus were measured at a frequency of 11 Hz and in a temperature range of -20 to 150 ° C. The value of “loss elastic modulus / storage elastic modulus” at each temperature is calculated as tan δ of that temperature, and the maximum value of tan δ in the range of −5 to 120 ° C. is referred to as “the maximum value of tan δ of the second substrate”. did.

[Stress relaxation rate of second substrate]
Similarly to the above, a second test substrate was prepared on a release sheet and cut to 15 mm × 140 mm to form a sample. Using a universal tensile testing machine (Autograph AG-10kNIS manufactured by SHIMADZU), gripping both ends 20 mm of this sample, pulling at a speed of 200 mm per minute, stress A (N / m ² ) when stretched 10%, The stress B (N / m ² ) 1 minute after the stop of the tape stretching was measured. From the values of these stresses A and B, (A−B) / A × 100 (%) was calculated as the stress relaxation rate.

[Peeling evaluation]
The adhesive tape with release sheet obtained in Examples and Comparative Examples was set on a tape laminator (trade name “RAD-3510”, manufactured by Lintec Corporation) while peeling off the release sheet, and grooves were formed on the wafer surface by the tip dicing method. It was affixed to the formed 12-inch silicon wafer (thickness: 760 μm) under the following conditions.
Roll height: 0mm Roll temperature: 23 ° C (room temperature)
Table temperature: 23 ° C (room temperature)
The obtained silicon wafer with an adhesive tape was separated into pieces having a thickness of 30 μm and a chip size of 1 mm square by back surface grinding (tip dicing method).
After the back surface grinding, the ground surface was polished with DPG8760 manufactured by Disco Corporation. “Gettering DP” manufactured by Disco Corporation was used for the grinding wheel. By this polishing, the damaged portion of the chip (grinding marks, chipping) was removed.
After completion of dry polishing, the presence or absence of deformation of the end of the adhesive tape and the number of chips held on the end of the adhesive tape were confirmed. The deformation of the end portion of the adhesive tape was evaluated based on the interval between the adhesive tape and the suction table, and when there was a portion having a gap between the adhesive tape and the suction table, it was regarded as defective. Moreover, the chip group currently hold | maintained on the adhesive tape was observed, and when the chip | tip which peeled was confirmed, it was set as the defect.

  In addition, all the mass parts of the following examples and comparative examples are solid content values.

[Example 1]
(1) First base material A polyethylene terephthalate film (Young's modulus: 2500 MPa) having a thickness of 50 μm was prepared as a first base material.

(2) Second substrate (synthesis of urethane acrylate oligomer)
A bifunctional urethane acrylate oligomer (UA-1) having a mass average molecular weight (Mw) of 5000 is reacted with a terminal isocyanate urethane prepolymer obtained by reacting a polyester diol with isophorone diisocyanate. Got.

(Preparation of composition for forming second substrate)
40 parts by mass of the urethane acrylate oligomer (UA-1) synthesized above, 40 parts by mass of isobornyl acrylate (IBXA), and 20 parts by mass of phenylhydroxypropyl acrylate (HPPA) are blended, and further as a photopolymerization initiator. 2.0 parts by mass of 1-hydroxycyclohexyl phenyl ketone (manufactured by BASF, product name “Irgacure 184”) and 0.2 parts by mass of a phthalocyanine pigment were blended to prepare a second substrate-forming composition.

(3) Laminated substrate The second substrate-forming composition obtained above is applied to one surface of the first substrate, and ultraviolet rays are applied under the conditions of an illuminance of 160 mW / cm ² and an irradiation amount of 500 mJ / cm ^2. The second base material forming composition was cured by irradiation to obtain a laminated base material having a second base material having a thickness of 30 μm on the first base material.

(4) Preparation of pressure-sensitive adhesive composition Acrylic polymer obtained by copolymerizing 65 parts by mass of butyl acrylate (BA), 20 parts by mass of methyl methacrylate (MMA), and 15 parts by mass of 2-hydroxyethyl acrylate (2HEA). (B) is reacted with 2-methacryloyloxyethyl isocyanate (MOI) so as to be added to 80 mol% of the total hydroxyl groups of the acrylic polymer (b), thereby energy beam curable acrylic resin. (Mw: 500,000) was obtained.

  To 100 parts by mass of this energy ray-curable acrylic resin, 6 parts by weight of polyfunctional urethane acrylate (trade name: Shikou UT-4332, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) which is an energy ray-curable compound, an isocyanate-based crosslinking agent (Tosoh Co., Ltd., trade name: Coronate L) 0.375 parts by mass based on solid content and 1 part by weight of a photopolymerization initiator consisting of bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide were added. The coating liquid of the pressure-sensitive adhesive composition was adjusted by diluting with a solvent.

(5) Preparation of pressure-sensitive adhesive tape On the release-treated surface of a release sheet (manufactured by Lintec Corporation, trade name: SP-PET 381031), the thickness after drying the coating liquid of the pressure-sensitive adhesive composition obtained above is 20 μm. The adhesive layer was formed on the release sheet by coating and drying by heating. This pressure-sensitive adhesive layer was affixed to the surface of the first base material of the laminated base material to obtain a pressure-sensitive adhesive tape with a release sheet.
In addition, the storage elastic modulus in 23 degreeC of an adhesive layer was 0.15 MPa. The storage modulus of the second substrate at 23 ° C. was 250 MPa, the stress relaxation rate was 90%, and the maximum value of tan δ was 1.24.

[Example 2]
Adhesive tape in the same manner as in Example 1 except that a composite film (thickness 80 μm) of low density polyethylene 27.5 μm / polyethylene terephthalate 25 μm / low density polyethylene 27.5 μm was used as the base material instead of the laminated base material. Got.

[Comparative Example 1]
An adhesive tape was obtained in the same manner as in Example 1 except that a commercially available polyvinyl chloride film (thickness 80 μm) was used as the base material instead of the laminated base material.

[Comparative Example 2]
The same procedure as in Example 1 was conducted except that Nucrel (registered trademark: Mitsui / DuPont Polychemical), which is an ethylene / methacrylic acid copolymer film (thickness 80 μm), was used as the base material instead of the laminated base material. An adhesive tape was obtained.

  The characteristics of the base materials used in Examples and Comparative Examples were evaluated, and peeling evaluation was performed using each adhesive tape. The results are shown in Table 1.

From the above results, it can be seen that if the absolute value of the 60 ° C. TMA value is 30 μm or less, the adhesive tape is not deformed even if dry polishing is performed, and the chip can be held well. Further, in addition to the adhesive tapes described in detail in Examples and Comparative Examples, it was confirmed by tests using various adhesive tapes that good results were obtained if the absolute value of the TMA value at 60 ° C. was 30 μm or less. . Similarly, the absolute value of the dimensional change rate at 60 ° C. for 3 minutes and the elastic modulus change rate E _(23-60) (%) are also 0.8% or less and 30% or less, respectively, by tests using various adhesive tapes. Then, it was confirmed that better results could be obtained.

Claims (7)

A pressure-sensitive adhesive tape comprising a base material and a pressure-sensitive adhesive layer provided on one side thereof,
The adhesive tape whose absolute value of the 60 degreeC TMA value of the said base material is 30 micrometers or less.   The pressure-sensitive adhesive tape according to claim 1, wherein an absolute value of a dimensional change rate after holding the substrate at 60 ° C for 3 minutes is 0.8% or less. The tensile elastic modulus at 23 ° C. of substrate _{(E 23)} and the tensile modulus at ₆₀ ℃ _(E 60) because sought modulus change rate _{E (23-60)} is 30% or less claim 1 or 2 The adhesive tape as described in.   In the process of grinding the back surface of a semiconductor wafer having grooves formed on the surface of the semiconductor wafer and separating the semiconductor wafer into semiconductor chips by the grinding, the semiconductor wafer is used by being affixed to the surface of the semiconductor wafer. 4. The adhesive tape according to any one of 3.   The pressure-sensitive adhesive tape according to claim 4, comprising a step of dry polishing after the semiconductor wafer is separated into semiconductor chips. Forming a groove from the surface side of the semiconductor wafer;
A step of attaching the adhesive tape according to any one of claims 1 to 4 to the surface of the semiconductor wafer;
A step of grinding the semiconductor wafer with the adhesive tape affixed to the front surface and the groove formed from the back side, removing the bottom of the groove and dividing it into a plurality of chips;
Peeling the adhesive tape from the plurality of chips;
A method for manufacturing a semiconductor device comprising: The method of manufacturing a semiconductor device according to claim 6, further comprising a step of dry polishing after the semiconductor wafer is separated into semiconductor chips.