Work processing tape and producing method of laminate

Abstract

To provide a work processing tape capable of sufficiently holding and protecting a work without including a base material and an intermediate layer, and capable of rapidly discharging static electricity generated by winding out of a tape, by suppressing generation of wrinkle even when stretched for pasting the work.SOLUTION: A work processing tape 10 according to the present invention is substantially composed of two layers, a surface coating layer 2 and an adhesive layer 4. When a tensile test of the work processing tape is conducted at 23°C, the strain from the start of tension until the tensile force reaches 2.5 N / 15 mm is 20% or less, and the product of the volume resistivity Rv (unit: Ω cm) of the work processing tape and the surface resistivity Rs (unit: Ω / sq.) of the surface coating layer is 1030 Ω2 cm / sq. or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a workpiece processing tape, particularly to a workpiece processing tape that is preferably used to temporarily protect the surface of a workpiece and hold the workpiece when processing the workpiece, such as a semiconductor wafer, through processes such as back grinding, etc. The present invention also relates to a method for producing a laminate of the workpiece processing tape and the workpiece. [Background technology]

[0002] Chips on which circuits such as semiconductor chips are formed are obtained as individual workpieces by dividing a workpiece such as a wafer on which multiple circuits are formed. With the rapid progress of miniaturization and multifunctionality of electronic devices incorporating such chips, there is a demand for chips to be smaller, thinner, and more dense. To reduce the size and height of chips, it is common to form circuits on the surface of the workpiece and then grind the backside of the workpiece to reduce the thickness of the chip.

[0003] When grinding the backside of a workpiece, a workpiece processing tape called backgrind tape is applied to the surface of the workpiece to temporarily protect the circuits on the surface of the workpiece and to hold the workpiece in place.

[0004] Such workpiece processing tapes are adhesive tapes consisting of a base film and an adhesive layer. When the workpiece has bumps such as protruding electrodes on its surface, a soft intermediate layer may be interposed between the base film and the adhesive layer to absorb the height difference of the bumps and keep the workpiece flat.

[0005] In order to hold the workpiece during processing and to facilitate removal of the workpiece after processing is complete, an energy ray-curable adhesive is sometimes used in the adhesive layer of the workpiece processing tape. The energy ray-curable adhesive holds the workpiece with sufficient adhesive strength before energy ray irradiation, and when irradiated with energy ray, it polymerizes and hardens, reducing the adhesive strength and making it easy to remove the workpiece from the adhesive layer. Energy ray-curable compositions are also sometimes used as intermediate layers.

[0006] However, the adhesive strength of the adhesive layer and intermediate layer is reduced by energy ray irradiation, which reduces the adhesion between the base film and the adhesive layer, between the intermediate layer and the adhesive layer, and between the base film and the intermediate layer, and this can result in the adhesive or intermediate layer being transferred to the workpiece when the workpiece is removed.

[0007] To address these issues, Patent Document 1 (JP 2013-23665 A) discloses a "pressure-sensitive adhesive sheet comprising a substrate film, an anchor coat layer containing a compound having energy ray-polymerizable groups, and an energy ray-curable pressure-sensitive adhesive layer laminated in this order." Both the anchor coat layer and the pressure-sensitive adhesive layer are in an uncured state (i.e., not irradiated with energy rays). After a predetermined processing step is completed, energy rays are irradiated and the workpiece is removed from the pressure-sensitive adhesive sheet. During curing of the energy ray-curable pressure-sensitive adhesive, at least a portion of the energy ray-polymerizable groups contained in the anchor coat layer also polymerize, forming a covalent bond between a portion of the pressure-sensitive adhesive layer and the anchor coat layer, thereby adhering the pressure-sensitive adhesive layer to the substrate via the anchor coat layer. As a result, adhesion between the substrate film and the pressure-sensitive adhesive layer is maintained even after curing of the energy ray-curable pressure-sensitive adhesive, preventing the pressure-sensitive adhesive layer from transferring to the workpiece.

[0008] However, the adhesive sheet of Patent Document 1 requires an anchor coat layer, which increases the production process and raw material costs, resulting in a higher product price. Furthermore, because of its multi-layer structure, the possibility of the adhesive layer transferring to the workpiece due to delamination cannot be completely eliminated. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-23665 Summary of the Invention [Problem to be solved by the invention]

[0010] Therefore, the inventors investigated the use of a workpiece processing tape that does not include a substrate or intermediate layer, but is essentially a single-layer adhesive layer, to hold and protect workpieces. However, with a single-layer adhesive layer, the adhesive layer adheres to the work table during processing of the workpiece, making peeling difficult. For this reason, they came up with the idea of ​​providing a relatively hard surface coating layer on the surface of the adhesive layer facing the worktable. A workpiece processing tape consisting of a surface coating layer and an adhesive layer has fewer constituent layers and is less susceptible to interlayer peeling, reducing the possibility of the adhesive layer transferring to the workpiece and reducing costs.

[0011] However, because the workpiece processing tape is composed of a soft adhesive layer and an extremely thin surface coating layer, various defects occur when the workpiece processing tape is applied to the surface of a workpiece, which are not observed with conventional workpiece processing tapes having a base film. Workpiece processing tapes are typically stored as rolls. When applying the workpiece processing tape to a workpiece, the tape is unwound from the roll and applied to the workpiece. During this process, tension is applied to the workpiece processing tape. When the workpiece processing tape is composed of a soft adhesive layer and an extremely thin surface coating layer, wrinkles may occur along the stretching direction as the tape is stretched. Wrinkles in the workpiece processing tape not only result in poor appearance, but also in uneven adhesion between the workpiece processing tape and the workpiece during application, which can prevent proper application. In this case, the tape must be peeled off and reapplied, reducing work efficiency.

[0012] Furthermore, static electricity is generated when workpiece processing tape is unwound from a roll. If charged workpiece processing tape is applied to a workpiece such as a semiconductor wafer, the static electricity can damage the workpiece. In particular, in the case of semiconductor wafers, damage to the circuitry can reduce product yield.

[0013] The present invention has been made in consideration of the above circumstances, and aims to provide a workpiece processing tape that can adequately hold and protect a workpiece without including a substrate or intermediate layer, that suppresses the occurrence of wrinkles when stretched to be attached to the workpiece, and that can quickly discharge static electricity generated when the tape is unwound. [Means for solving the problem]

[0014] The aspects of the present invention are as follows. (1) A work processing tape essentially consisting of two layers: a surface coating layer and a pressure-sensitive adhesive layer, When a tensile test of the workpiece processing tape is conducted at 23°C, the strain from the start of tension until the tensile force reaches 2.5 N / 15 mm is 20% or less, The product of the volume resistivity Rv (unit: Ω cm) of the workpiece processing tape and the surface resistivity Rs (unit: Ω / sq.) of the surface coating layer is 10 30 Ω 2 cm / sq. or less, Tape for work processing. (2) The volume resistivity Rv of the workpiece processing tape is 10 15 The tape for workpiece processing according to (1), having a resistivity of Ω·cm or less. (3) The surface resistivity Rs of the surface coating layer is 10 15 The tape for workpiece processing according to (1), wherein the hardness is Ω / sq. or less. (4) The tape for workpiece processing according to (1), wherein the adhesive layer has an adhesive strength of 700 mN / 25 mm or more. (5) The tape for workpiece processing according to (1), wherein the thickness of the adhesive layer is 90 μm or more. (6) The tape for workpiece processing according to (1), wherein the surface coating layer has a thickness of 0.2 to 5 μm. (7) The workpiece processing tape according to (1), wherein the pressure-sensitive adhesive layer is a cured product of a composition for pressure-sensitive adhesive layer containing an energy ray-curable compound. (8) The workpiece processing tape according to (1), wherein the adhesive layer contains an antistatic agent. (9) The tape for workpiece processing according to (8), wherein the antistatic agent contains an ionic liquid. (10) A workpiece processing tape roll obtained by winding the workpiece processing tape according to any one of (1) to (9) above into a roll. (11) A method for producing a laminate of a workpiece and a tape for workpiece processing, comprising a step of adhering the adhesive layer of the tape for workpiece processing according to any one of (1) to (9) above to the surface of the workpiece. (12) A method for manufacturing a laminate of a workpiece and a workpiece processing tape, comprising the steps of unwinding the workpiece processing tape described in (10) from a roll of the tape and adhering the adhesive layer of the tape to the surface of the workpiece. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a work processing tape that can adequately hold and protect a workpiece without including a base material or intermediate layer, that suppresses the occurrence of wrinkles when stretched to be attached to a workpiece, and that can quickly discharge static electricity generated when the tape is unwound. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a cross-sectional schematic view of a tape for workpiece processing according to an embodiment of the present invention; [Figure 2] 3A to 3C are cross-sectional views illustrating an example of a manufacturing process for the workpiece processing tape according to the present embodiment. [Figure 3] 5A to 5C are cross-sectional views illustrating another example of the manufacturing process of the workpiece processing tape according to the present embodiment. [Figure 4] 1 is a schematic cross-sectional view showing a state in which a workpiece processing tape is attached to a circuit surface of a wafer. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0017] The present invention will be described in detail below based on specific embodiments with reference to the accompanying drawings. First, the main terms used in this specification will be explained.

[0018] The workpiece refers to a plate-like object to which the workpiece processing tape according to this embodiment is applied and which undergoes some processing in that state. Examples of workpieces include circular wafers (including those with orientation flats), rectangular panel-level packages, and strips (rectangular substrates) sealed with molded resin. Examples of wafers include semiconductor wafers such as silicon wafers, gallium arsenide wafers, silicon carbide wafers, gallium nitride wafers, and indium phosphide wafers, as well as insulator wafers such as glass wafers, lithium tantalate wafers, and lithium niobate wafers. They may also be reconstructed wafers made of resin and semiconductors used to fabricate fan-out packages, etc.

[0019] The "surface" of a workpiece refers to the surface on which circuits, electrodes, etc. are formed, and the "back" of a workpiece refers to the surface on which no circuits, etc. are formed. The electrodes may be convex electrodes such as bumps.

[0020] The processing of the workpiece refers to processes such as grinding the back side of the workpiece, dividing the workpiece into individual pieces (e.g., dicing), marking the back side of the workpiece with a laser marker or the like, and forming circuits or protruding electrodes on the front side of the workpiece. However, from the viewpoint of easily achieving the effects of the present invention, it is more preferable that the processing of the workpiece is a process of grinding the back side of the workpiece.

[0021] The surface coating layer is a thin resin layer that covers one side of the adhesive layer and prevents the workpiece processing tape from sticking to components of semiconductor manufacturing equipment (for example, a suction table).

[0022] The term "(meth)acrylate" is used to refer to both "acrylate" and "methacrylate," and similar terms.

[0023] "Energy rays" refers to ultraviolet rays, electron beams, etc., and is preferably ultraviolet rays.

[0024] Unless otherwise specified, the "weight average molecular weight" is a polystyrene equivalent value measured by gel permeation chromatography (GPC). Measurements by this method are performed, for example, using a high-speed GPC device "HLC-8120GPC" manufactured by Tosoh Corporation, with a high-speed column "TSK guard column H" XL -H", "TSK Gel GMH XL ", "TSK Gel G2000 H XL (All products of Tosoh Corporation) connected in this order are used, and the column temperature is 40°C, the liquid flow rate is 1.0 mL / min, and the detector is a differential refractometer.

[0025] The release film is a film that supports the pressure-sensitive adhesive layer and the surface coating layer in a releasable manner. The term "film" is not limited to a specific thickness, and is used to include a sheet.

[0026] The mass ratios in the descriptions of compositions such as the pressure-sensitive adhesive layer composition are based on the active ingredient (solid content), and do not include the solvent unless otherwise specified.

[0027] Next, the configuration of each component of the workpiece processing tape according to the present invention will be described in more detail. Note that, hereinafter, the workpiece processing tape according to the present invention may be simply referred to as "tape."

[0028] (Work processing tape 10) As shown in Figure 1, the workpiece processing tape 10 essentially consists of two layers: a surface coating layer 2 and an adhesive layer 4. Here, "essentially consists" means that it does not have any other layers that have the functionality to hold or protect the workpiece, but it does not preclude the inclusion of layers that are not involved in holding or protecting the workpiece. For example, a release film may be laminated on the adhesive layer 4 to prevent dust and other particles from adhering to the adhesive layer before the workpiece processing tape 10 is used.

[0029] The surface coating layer 2 may be a laminated structure of two or more layers with similar composition and properties, and the adhesive layer 4 may also be a laminated structure of two or more layers with similar composition and properties, but from the standpoint of manufacturing efficiency, it is preferable that both are single layers.

[0030] When a tensile test of the workpiece processing tape 10 is performed at 23°C, the strain from the start of tension until the tensile force reaches 2.5 N / 15 mm is 20% or less. After the tape tensile test begins, the tape is gradually stretched and the tensile force increases due to the resistance to the tape's recovery force. The fact that the strain from the start of tension until the tape reaches 2.5 N / 15 mm is 20% or less means that the tape undergoes little deformation even when tension is applied. Therefore, even when tension is applied to the tape when the workpiece processing tape of the present invention is unwound from the winder and applied to the workpiece, the tape undergoes little deformation and does not develop wrinkles. This allows for stable application of the tape to the workpiece. The strain is preferably 15% or less, more preferably 11% or less, even more preferably 5% or less, and particularly preferably 2.8% or less. Theoretically, the lower limit of the strain is 0%, but a tape that does not deform at all may have poor application workability, so the lower limit is preferably 0.5% or more, more preferably 1% or more, and particularly preferably 1.5% or more.

[0031] The strain measurement is performed in accordance with JIS K 7161. Specifically, a strip-shaped measurement sample, 15 mm wide and 150 mm long, is cut from the workpiece processing tape 10 and attached to a precision universal testing machine. The sample is stretched at a stretching rate of 200 mm / min. The strain (%) is calculated from the amount of elongation at the time when the tensile force reaches 2.5 N / 15 mm. The measurement is performed in an environment with a chuck distance (i.e., initial sample length) of 100 mm, 23°C, and 50% relative humidity. The strain (%) is calculated by determining the elongation Δ, which is the difference between the sample length (chuck distance) at the time when the tensile force reaches 2.5 N / 15 mm and the initial sample length (100 mm). The ratio of the elongation Δ to the initial sample length (100 mm) [= (Δ / 100) × 100] is defined as the strain (%).

[0032] The product of the volume resistivity Rv (unit: Ω·cm) of the workpiece processing tape and the surface resistivity Rs (unit: Ω / sq.) of the surface coating layer is 10 30 Ω 2 ·cm / sq. or less. Since the product of the volume resistivity Rv and the surface resistivity Rs of the workpiece processing tape is within the above range, the tape has antistatic properties. 30 Ω 2 Because the surface resistivity (Rs) is less than 1 / cm / sq., even if static electricity is generated when the tape is unwound from the reel, the static electricity can be discharged in a short time due to the effective action of bulk conduction that travels within the tape in a direction perpendicular to the thickness of the tape, and bulk conduction that travels within the tape in the thickness direction of the tape, and conduction on the tape surface. The unit of surface resistivity (Rs) can also be expressed as Ω, but to avoid confusion with electrical resistance, it is conventionally written as "Ω / sq."

[0033] The product of the volume resistivity Rv and the surface resistivity Rs of the workpiece processing tape (Rv × Rs) is preferably 1 × 10 29 Ω 2 cm / sq. or less, and more preferably 1×10 28 Ω 2 cm / sq. or less, and more preferably 1×10 27 Ω 2 cm / sq. or less, and particularly preferably 1×10 26 Ω2 ·cm / sq. or less. If a large amount of antistatic agent is added to the tape in order to reduce the product (Rv × Rs), the antistatic agent may bleed out of the tape and contaminate the workpiece. From this perspective, the product (Rv × Rs) is preferably 1 × 10 23 Ω 2 cm / sq. or more, and more preferably 1×10 24 Ω 2 cm / sq. or more, and particularly preferably 1×10 25 Ω 2 cm / sq. or more.

[0034] The volume resistivity of the workpiece processing tape can be measured by cutting the tape into a 10 cm x 10 cm piece and using the double ring electrode method (two-terminal method) in accordance with JIS K6911-1995. In this embodiment, the volume resistivity can be measured using an Advantest resistance meter (Digital Electrometer R8252) at an applied voltage of 100 V in an environment of 23°C and 50% RH.

[0035] The surface resistivity of the surface coating layer can be measured by cutting the tape into a 10 cm x 10 cm piece and using the double ring electrode method (two-terminal method) in accordance with JIS K6911-1995. In this embodiment, the surface resistivity can be measured using an Advantest resistance meter (Digital Electrometer R8252) at an applied voltage of 100 V in an environment of 23°C and 50% RH.

[0036] The volume resistivity Rv of the workpiece processing tape is preferably 10 to 1500 W, from the viewpoint of reducing the product (Rv × Rs) of the volume resistivity Rv and the surface resistivity Rs of the workpiece processing tape. 15 Ω·cm or less, and more preferably 5×10 14 Ω·cm or less, and more preferably 8×10 13 Ω·cm or less, and even more preferably 5×10 13 Ω·cm or less, and particularly preferably 2×10 13Ω·cm or less. If a large amount of antistatic agent is added to the tape to reduce the volume resistivity, the antistatic agent may bleed out from the tape and contaminate the workpiece. From this perspective, the volume resistivity is preferably 1×10 11 Ω·cm or more, and more preferably 1×10 12 Ω·cm or more, and particularly preferably 5×10 12 Ω·cm or more.

[0037] The surface resistivity Rs of the surface coating layer is preferably 10 to 1500 W, from the viewpoint of reducing the product (Rv × Rs) of the volume resistivity Rv and the surface resistivity Rs of the workpiece processing tape. 15 Ω / sq. or less, and more preferably 10 14 Ω / sq. or less, and particularly preferably 10 13 Ω / sq. or less. If an excessive amount of antistatic agent is added to the surface coating layer in order to reduce the surface resistivity, the surface coating layer may soften and stick to the suction table, making it difficult to peel off. From the viewpoint of reducing such a possibility, the surface resistivity is preferably 10 9 Ω / sq. or more, and more preferably 10 10 Ω / sq. or more, and particularly preferably 10 11 Ω / sq. or more.

[0038] The adhesive strength of the adhesive layer of the workpiece processing tape 10 is preferably 150 mN / 25 mm or more, more preferably 250 mN / 25 mm or more, and particularly preferably 700 mN / 25 mm or more, and is preferably 6000 mN / 25 mm or less, more preferably 4000 mN / 25 mm or less, and particularly preferably 3000 mN / 25 mm or less.

[0039] The adhesive strength is measured in accordance with JIS Z 0237. Specifically, a strip-shaped measurement sample obtained by cutting the workpiece processing tape 10 to a width of 25 mm is attached to a silicon wafer with a 2 kg roller in an environment of 23°C and 50% relative humidity, and after 20 minutes, the adhesive strength is determined as the peel force when the sample is peeled in a 180° direction at a speed of 300 mm / min using a universal (peel load) tester. A mirror-finished silicon wafer whose surface roughness Ra is smoothed to 5 nm ± 2 nm by buff polishing or the like is used, and the workpiece processing tape is attached to the mirror-finished surface to measure the adhesive strength.

[0040] When the adhesive strength of the workpiece processing tape 10 at 23°C is within the above range, the workpiece, such as a semiconductor wafer, can be stably held and its surface can be reliably protected when the workpiece is subjected to processing such as back grinding.

[0041] The thickness of the adhesive layer is not particularly limited, but from the viewpoint of ensuring reliable retention of the workpiece, it is preferably 90 μm or more, more preferably 100 μm or more, and particularly preferably 110 μm or more. Furthermore, since a thick adhesive layer can make it difficult to handle, the thickness of the adhesive layer is preferably 200 μm or less, more preferably 175 μm or less, and particularly preferably 150 μm or less.

[0042] The thickness of the surface coating layer is not particularly limited, but from the viewpoint of preventing adhesion to the work table, it is preferably 0.2 to 5 μm, more preferably 0.5 to 5 μm, and particularly preferably 1 to 4 μm. By setting the thickness of the surface coating layer within the above range, high performance tends to be maintained.

[0043] The storage modulus of the surface coating layer is not particularly limited, but from the viewpoint of preventing the workpiece processing tape from sticking to components of semiconductor manufacturing equipment (e.g., a suction table), the storage modulus (E') measured in a tensile mode is preferably 40 MPa or more, more preferably 60 MPa or more, and even more preferably 80 MPa or more at 23° C. The method for measuring the storage modulus (E') of the surface coating layer in the present invention will be described in detail in the Examples below.

[0044] The thickness of the workpiece processing tape 10 is not particularly limited, but from the viewpoint of ensuring reliable holding of the workpiece, it is preferably 90.2 μm or more, more preferably 100.5 μm or more, and particularly preferably 111 μm or more. Also, from the viewpoint of ease of handling, the thickness of the workpiece processing tape 10 is preferably 154 μm or less, more preferably 180 μm or less, and particularly preferably 205 μm or less.

[0045] The workpiece processing tape 10 is not particularly limited in terms of the composition or thickness of the surface coating layer or adhesive layer as long as the above-mentioned strain and Rv × Rs are satisfied, but non-limiting examples of the composition, etc. of the workpiece processing tape 10 of the present invention are described below.

[0046] (Adhesive layer 4) The adhesive layer is formed from a composition containing various removable pressure-sensitive adhesives, but it is preferable that it is composed of a cured product of an adhesive layer composition containing an energy ray-curable compound, which makes it relatively easy to control the properties of the tape within the desired range.

[0047] (Composition for pressure-sensitive adhesive layer) The composition for pressure-sensitive adhesive layer containing the energy ray-curable compound is cured by irradiation with energy rays. Upon curing, the fluidity decreases, but the adhesiveness is maintained and the stretchability decreases.

[0048] From the viewpoint of controlling the "strain" within a desired range, the composition for pressure-sensitive adhesive layer containing an energy ray-curable compound preferably contains a urethane (meth)acrylate (d1), more preferably further contains an energy ray-curable compound (d3) having an alicyclic or heterocyclic group having 6 to 20 ring atoms, and may further contain a polyfunctional energy ray-curable compound (d2) and / or an energy ray-curable compound (d4) having a functional group. Furthermore, the composition for pressure-sensitive adhesive layer may contain, in addition to the above components, an energy ray-curable compound (d5) other than components (d1) to (d4) or a photopolymerization initiator. Furthermore, the composition for pressure-sensitive adhesive layer may contain other additives within the range that does not impair the effects of the present invention.

[0049] Hereinafter, each component contained in the composition for pressure-sensitive adhesive layer containing the energy ray-curable compound will be described in detail.

[0050] (urethane (meth)acrylate (d1)) The urethane (meth)acrylate (d1) is a compound having at least a (meth)acryloyl group and a urethane bond, and has the property of being polymerized and cured by irradiation with energy rays. The urethane (meth)acrylate (d1) is an oligomer or a polymer.

[0051] The weight-average molecular weight (Mw) of component (d1) is preferably 1,000 to 100,000, more preferably 2,000 to 60,000, and even more preferably 3,000 to 20,000. The number of (meth)acryloyl groups (hereinafter also referred to as "number of functional groups") in component (d1) may be monofunctional, bifunctional, or trifunctional or higher, but is preferably monofunctional or bifunctional.

[0052] Component (d1) can be obtained, for example, by reacting a polyol compound with a polyvalent isocyanate compound to obtain a terminal isocyanate urethane prepolymer, and then reacting the resulting prepolymer with a (meth)acrylate having a hydroxy group. Component (d1) may be used alone or in combination of two or more.

[0053] The polyol compound used as the raw material for component (d1) is not particularly limited as long as it has two or more hydroxy groups. It may be a bifunctional diol, a trifunctional triol, or a polyol with four or more functional groups, but a bifunctional diol is preferred, and a polyolefin diol is more preferred.

[0054] Examples of polyisocyanate compounds include aliphatic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate; alicyclic diisocyanates such as isophorone diisocyanate, norbornane diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, and ω,ω'-diisocyanatodimethylcyclohexane; and aromatic diisocyanates such as 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, tolidine diisocyanate, tetramethylene xylylene diisocyanate, and naphthalene-1,5-diisocyanate.

[0055] Among these, isophorone diisocyanate, hexamethylene diisocyanate, and xylylene diisocyanate are preferred.

[0056] The urethane (meth)acrylate (d1) can be obtained by reacting a (meth)acrylate having a hydroxy group with a terminal isocyanate urethane prepolymer obtained by reacting the above-mentioned polyol compound with a polyisocyanate compound. The (meth)acrylate having a hydroxy group is not particularly limited as long as it is a compound having a hydroxy group and a (meth)acryloyl group in at least one molecule.

[0057] Specific examples of (meth)acrylates having a hydroxy group include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 4-hydroxycyclohexyl (meth)acrylate, 5-hydroxycyclooctyl (meth)acrylate, 2-hydroxy-3-phenyloxypropyl (meth)acrylate, pentaerythritol tri(meth)acrylate, polyethylene glycol mono(meth)acrylate, and polypropylene glycol mono(meth)acrylate; hydroxy group-containing (meth)acrylamides such as N-methylol (meth)acrylamide; and reaction products obtained by reacting a diglycidyl ester of vinyl alcohol, vinylphenol, or bisphenol A with (meth)acrylic acid.

[0058] Among these, hydroxyalkyl (meth)acrylate is preferred, and 2-hydroxyethyl (meth)acrylate is more preferred.

[0059] The conditions for reacting the isocyanate-terminated urethane prepolymer and the (meth)acrylate having a hydroxy group are preferably such that the reaction is carried out at 60 to 100° C. for 1 to 4 hours in the presence of a solvent and a catalyst, which are added as needed.

[0060] The content of component (d1) in the composition for adhesive layer is preferably 20 to 80 parts by mass, more preferably 30 to 70 parts by mass, and even more preferably 40 to 65 parts by mass, relative to the total amount (100 parts by mass) of the composition for adhesive layer.

[0061] (Multifunctional energy ray-curable compound (d2)) A polyfunctional energy ray-curable compound refers to a compound other than component (d1) that has two or more energy ray-curable unsaturated groups. The energy ray-curable unsaturated group is a functional group containing a carbon-carbon double bond, such as a (meth)acryloyl group, a vinyl group, an allyl group, or a vinylbenzyl group. Two or more types of energy ray-curable unsaturated groups may be combined. A three-dimensional network structure (crosslinked structure) is formed by reaction of the energy ray-curable unsaturated group in the polyfunctional energy ray-curable compound with the (meth)acryloyl group in component (d1) or by reaction of the energy ray-curable unsaturated groups in component (d2) with each other. When a polyfunctional energy ray-curable compound is used, the crosslinked structure formed by energy ray irradiation increases compared to when a compound containing only one energy ray-curable unsaturated group is used. This results in the pressure-sensitive adhesive layer exhibiting unique viscoelasticity and making it easier to relieve stress during back grinding.

[0062] Although the definition of component (d2) overlaps with the definitions of components (d3) and (d4) described below, the overlapping portions are considered to be included in component (d2). For example, a compound having an alicyclic or heterocyclic group with 6 to 20 ring atoms and two or more energy ray-curable unsaturated groups is included in the definitions of both component (d2) and component (d3), but in the present invention, such a compound is considered to be included in component (d2). Furthermore, a compound containing a functional group such as a hydroxyl group, epoxy group, amide group, or amino group and having two or more energy ray-curable unsaturated groups is included in the definitions of both component (d2) and component (d4), but in the present invention, such a compound is considered to be included in component (d2).

[0063] From the above viewpoints, the number of energy ray-curable unsaturated groups (number of functional groups) in the polyfunctional energy ray-curable compound (d2) is preferably 2 to 10, more preferably 3 to 6.

[0064] The weight average molecular weight of the component (d2) is preferably 30 to 40,000, more preferably 100 to 10,000, and even more preferably 200 to 1,000.

[0065] Specific examples of the component (d2) include diethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, divinylbenzene, vinyl (meth)acrylate, divinyl adipate, and N,N'-methylenebis(meth)acrylamide.

[0066] The component (d2) may be used alone or in combination of two or more types. Among these, dipentaerythritol hexa(meth)acrylate is preferred.

[0067] The content of component (d2) in the composition for adhesive layer is preferably 0 to 40 parts by mass, more preferably 0.5 to 20 parts by mass, and even more preferably 1 to 15 parts by mass, relative to the total amount (100 parts by mass) of the composition for adhesive layer.

[0068] (Energy ray-curable compound (d3) having an alicyclic group or heterocyclic group having 6 to 20 ring atoms) Component (d3) is an energy ray-curable compound other than component (d1) that has an alicyclic group or heterocyclic group having 6 to 20 ring atoms, and is preferably a compound having at least one (meth)acryloyl group, more preferably a compound having one (meth)acryloyl group. Use of component (d3) can improve the film-forming properties of the resulting pressure-sensitive adhesive layer composition.

[0069] Although the definition of component (d3) overlaps with the definition of component (d4) described below, the overlapping portion is included in component (d4). For example, a compound having at least one (meth)acryloyl group, an alicyclic or heterocyclic group having 6 to 20 ring atoms, and a functional group such as a hydroxyl group, an epoxy group, an amide group, or an amino group is included in the definitions of both component (d3) and component (d4), and in the present invention, such a compound is considered to be included in component (d4).

[0070] Specific examples of component (d3) include alicyclic group-containing (meth)acrylates such as isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyloxy (meth)acrylate, cyclohexyl (meth)acrylate, and adamantane (meth)acrylate; and heterocyclic group-containing (meth)acrylates such as tetrahydrofurfuryl (meth)acrylate and morpholine (meth)acrylate. The component (d3) may be used alone or in combination of two or more types.

[0071] Among the alicyclic group-containing (meth)acrylates, isobornyl (meth)acrylate is preferred, and among the heterocyclic group-containing (meth)acrylates, tetrahydrofurfuryl (meth)acrylate is preferred.

[0072] The content of component (d3) in the composition for adhesive layer is preferably 10 to 60 parts by mass, more preferably 20 to 55 parts by mass, and even more preferably 25 to 50 parts by mass, relative to the total amount (100 parts by mass) of the composition for adhesive layer.

[0073] (Energy ray-curable compound (d4) having a functional group) Component (d4) is an energy ray-curable compound other than component (d1) that contains a functional group such as a hydroxyl group, an epoxy group, an amide group, or an amino group, and is preferably a compound having at least one (meth)acryloyl group, more preferably a compound having one (meth)acryloyl group.

[0074] Component (d4) has good compatibility with component (d1), making it easier to adjust the viscosity of the pressure-sensitive adhesive layer composition or the coating agent described below within an appropriate range, and also making it easier to achieve good cushioning performance even when the pressure-sensitive adhesive layer is relatively thin.

[0075] Examples of component (d4) include hydroxyl group-containing (meth)acrylates, epoxy group-containing compounds, amide group-containing compounds, amino group-containing (meth)acrylates, etc. Among these, hydroxyl group-containing (meth)acrylates are preferred.

[0076] Examples of hydroxyl group-containing (meth)acrylates include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, phenylhydroxypropyl (meth)acrylate, and 2-hydroxy-3-phenoxypropyl acrylate.

[0077] The component (d4) may be used alone or in combination of two or more types. The content of component (d4) in the composition for adhesive layer is preferably 0 to 30 parts by mass, more preferably 1 to 20 parts by mass, and even more preferably 2 to 10 parts by mass relative to the total amount (100 parts by mass) of the composition for adhesive layer, in order to improve the film-forming properties of the composition for adhesive layer and to adjust the polarity of the adhesive layer.

[0078] (Energy ray-curable compound (d5) other than components (d1) to (d4)) The pressure-sensitive adhesive layer-forming composition may contain a monofunctional energy ray-curable compound (d5) other than the above components (d1) to (d4) within the range that does not impair the effects of the present invention.

[0079] Examples of component (d5) include alkyl (meth)acrylates having an alkyl group having 1 to 20 carbon atoms, and vinyl compounds such as styrene, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, N-vinyl formamide, N-vinyl pyrrolidone, and N-vinyl caprolactam. Component (d5) may be used alone or in combination of two or more.

[0080] The content of component (d5) in the composition for forming a pressure-sensitive adhesive layer is preferably 0 to 20 parts by mass, more preferably 0 to 10 parts by mass, even more preferably 0 to 5 parts by mass, and particularly preferably 0 to 2 parts by mass, relative to the total amount (100 parts by mass) of the composition for forming a pressure-sensitive adhesive layer.

[0081] (Photopolymerization initiator) It is preferable that the composition for pressure-sensitive adhesive layer further contains a photopolymerization initiator from the viewpoint of shortening the polymerization time by energy ray irradiation and reducing the amount of energy ray irradiation when forming the pressure-sensitive adhesive layer.

[0082] Examples of the photopolymerization initiator include benzoin compounds, acetophenone compounds, acylphosphinoxide compounds, titanocene compounds, thioxanthone compounds, peroxide compounds, and further photosensitizers such as amines and quinones. More specific examples include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl phenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyrolnitrile, dibenzyl, diacetyl, 8-chloroanthraquinone, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

[0083] These photopolymerization initiators can be used alone or in combination of two or more.

[0084] The content of the photopolymerization initiator in the composition for the adhesive layer is preferably 0.05 to 15 parts by mass, more preferably 0.1 to 10 parts by mass, and even more preferably 0.3 to 5 parts by mass, relative to the total amount (100 parts by mass) of the composition for the adhesive layer.

[0085] (antistatic agent) The pressure-sensitive adhesive layer composition preferably contains an antistatic agent from the viewpoint of controlling the product of the volume resistivity Rv of the workpiece processing tape and the surface resistivity Rs of the surface coating layer within a desired range. The antistatic agent is not particularly limited, but it is preferable to use an ionic liquid from the viewpoint of ease of handling and simple control of resistivity.

[0086] The ionic liquid in this embodiment is not particularly limited as long as it is a salt that exists in a liquid state at room temperature (25°C, 1 atmosphere). The melting point of the ionic liquid is preferably 150°C or lower, and more preferably 100°C or lower. On the other hand, the lower limit of the melting point of the ionic liquid is not particularly limited, and is, for example, -50°C or higher.

[0087] Examples of cationic components that constitute ionic liquids include pyridinium-based compounds such as pyridinium and alkylpyridinium; pyrimidinium-based compounds; pyrazolium-based compounds; pyrrolidinium-based compounds; piperidinium-based compounds; cyclic pyrrolidinium-based compounds; imidazolium-based compounds such as imidazolium and dialkylimidazolium; ammonium-based compounds such as tetraalkylammonium; and phosphine-based compounds such as phosphonium, trialkylsulfonium, and tetraalkylphosphonium.

[0088] Examples of anion components that make up ionic liquids include Cl - , Br - , I - , AlCl4 - , Al2Cl7 - , BF4 - , PF6 - , ClO4 - , NO3 - , CH3COO - , CF3COO - , CH3SO3 -, CF3SO3 - , (FSO2)2N - , (CF3SO2)2N - , (CF3SO2)3C - , AsF6 - , SbF6 - , NbF6 - , TaF6 - , F(HF) n - , (CN)2N - , C4F9SO3 - , (C2F5SO2)2N - , C3F7COO - , (CF3SO2)(CF3CO)N - etc.

[0089] Specific examples of commercially available ionic liquids include those manufactured by Koei Chemical Co., Ltd. under the product names "IL-A1," "IL-A2," "IL-MA1," "IL-MA2," "IL-MA3," "IL-OH2," and "IL-OH9," and those manufactured by Nippon Nyukazai Co., Ltd. under the product names "Aminoion (registered trademark) AS100," "Aminoion AS300," "Aminoion AS400," and "Aminoion RE3000MF."

[0090] The antistatic agent is not limited to the ionic liquid, and various known antistatic agents may be used. These antistatic agents may be used alone or in combination of two or more.

[0091] The content of the antistatic agent in the composition for pressure-sensitive adhesive layer is preferably 0.1 parts by mass or more, particularly preferably 0.2 parts by mass or more, and even more preferably 0.3 parts by mass or more, relative to the total amount (100 parts by mass) of the composition for pressure-sensitive adhesive layer. Furthermore, the content is preferably 6 parts by mass or less, particularly preferably 4 parts by mass or less, and even more preferably 2 parts by mass or less, relative to the total amount (100 parts by mass) of the composition for pressure-sensitive adhesive layer. By incorporating the antistatic agent in an amount equal to or greater than the above-mentioned lower limit, sufficient antistatic properties are easily imparted to the pressure-sensitive adhesive layer. Furthermore, by incorporating the antistatic agent in an amount equal to or less than the above-mentioned upper limit, the cohesive strength of the pressure-sensitive adhesive layer is maintained high, the pressure-sensitive adhesive layer is likely to have desirable viscoelasticity, and the adhesive strength of the pressure-sensitive adhesive layer of the above-mentioned workpiece processing tape is likely to be further increased.

[0092] (Other additives) The composition for pressure-sensitive adhesive layer may contain other additives as long as the effects of the present invention are not impaired. Examples of other additives include antioxidants, softeners (plasticizers), fillers, rust inhibitors, pigments, dyes, etc. When these additives are blended, the content of each additive in the composition for pressure-sensitive adhesive layer is preferably 0.01 to 6 parts by mass, more preferably 0.1 to 3 parts by mass, relative to the total amount (100 parts by mass) of the composition for pressure-sensitive adhesive layer.

[0093] The pressure-sensitive adhesive layer formed from the composition for pressure-sensitive adhesive layer containing the energy ray-curable compound is preferably obtained by polymerizing and curing the composition for pressure-sensitive adhesive layer having the above-mentioned composition by energy ray irradiation. In other words, the pressure-sensitive adhesive layer is preferably a product obtained by curing the composition for pressure-sensitive adhesive layer.

[0094] Therefore, the pressure-sensitive adhesive layer preferably contains a repeating unit derived from component (d1), and more preferably further contains a repeating unit derived from component (d3). The pressure-sensitive adhesive layer may also contain a repeating unit derived from component (d2) and / or a repeating unit derived from component (d4), or may contain a repeating unit derived from component (d5). The content ratio of each repeating unit in the pressure-sensitive adhesive layer usually corresponds to the ratio (charge ratio) of each component constituting the composition for the pressure-sensitive adhesive layer.

[0095] (Surface coating layer 2) The surface coating layer is formed from various hard thin films, but is preferably a cured product of a composition containing a curable resin (A) and an inorganic filler, as this is easy to produce and gives a hard surface coating layer.

[0096] (Surface Coating Layer Composition) The surface coating layer composition preferably contains 10 to 50 parts by mass, more preferably 15 to 40 parts by mass, and particularly preferably 20 to 30 parts by mass of inorganic filler per 100 parts by mass of the cured surface coating layer composition. There is typically no substantial difference between the amount of inorganic filler in the surface coating layer composition before curing and the amount of inorganic filler in the cured surface coating layer composition. Therefore, in the present invention, the amount of inorganic filler in the surface coating layer composition before curing is considered to be the amount of inorganic filler in the cured surface coating layer composition. By setting the inorganic filler content in the surface coating layer within the above range, excellent performance as a surface coating layer can be achieved and cracks can be prevented from occurring in the surface coating layer during the workpiece processing process, thereby more efficiently suppressing performance degradation.

[0097] The curable resin (A) is not particularly limited, but may be an energy ray curable resin, a thermosetting resin, or the like, and preferably an energy ray curable resin containing an energy ray curable group.

[0098] The energy ray-curable resin is not particularly limited, but for example, an oligomer-based energy ray-curable resin such as an energy ray-curable urethane (meth)acrylate oligomer or epoxy (meth)acrylate oligomer is preferably used. The weight-average molecular weight Mw (referring to a polystyrene equivalent value determined by gel permeation chromatography) of the urethane (meth)acrylate oligomer or epoxy (meth)acrylate oligomer is usually about 1,000 to 70,000, preferably in the range of 1,500 to 60,000. The above urethane (meth)acrylate oligomer or epoxy (meth)acrylate oligomer can be used alone or in combination of two or more.

[0099] The energy ray-curable resin may also be a polymer having an energy ray-curable functional group in its side chain. If such a polymer is used as the energy ray-curable resin, the adhesion to the pressure-sensitive adhesive layer can be further improved without reducing the crosslink density. For example, such a polymer may have an acrylic polymer main chain and an energy ray-curable double bond or an epoxy group as a functional group in its side chain.

[0100] The surface coating layer composition contains preferably 50 to 90 parts by mass, more preferably 60 to 85 parts by mass, and particularly preferably 70 to 80 parts by mass of the curable resin (A) per 100 parts by mass of the surface coating layer composition.

[0101] By mixing a photopolymerization initiator into an energy ray-curable resin, the polymerization and curing time and irradiation dose due to energy ray irradiation can be reduced. Examples of the photopolymerization initiator include photopolymerization initiators such as benzoin compounds, acetophenone compounds, acylphosphinoxide compounds, titanocene compounds, thioxanthone compounds, and peroxide compounds, and photosensitizers such as amines and quinones. Specific examples include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether.

[0102] The surface coating layer composition may contain a binder component other than the curable resin (A) to impart flexibility (ability to prevent cracking) to the surface coating layer. Examples of such binder components include acrylic resins, polyester resins, urethane resins, and polyamide resins.

[0103] The surface coating layer composition may contain an antistatic agent similar to that contained in the adhesive layer composition in order to further reduce the volume resistivity of the workpiece processing tape. However, in a workpiece processing tape essentially consisting of two layers, a surface coating layer and an adhesive layer, the thick adhesive layer has a greater effect than the thin surface coating layer, so the surface coating layer composition may be essentially free of an antistatic agent. Here, "substantially free" means that the content of the antistatic agent is less than 0.1 parts by mass per 100 parts by mass of the surface coating layer composition. Furthermore, the substantial absence of an antistatic agent also reduces costs.

[0104] The composition for the surface coating layer may contain a dispersant to improve the dispersibility of the inorganic filler, and may also contain additives such as colorants, including pigments and dyes.

[0105] (Tape roll for work processing) The workpiece processing tape may be in the form of sheets pre-cut to fit the shape of the workpiece to be adhered, but is usually wound into a roll to form a wound body, which is transported and stored, and when used, it is unwound from the wound body and applied to the workpiece, and then unnecessary portions are cut off to fit the shape of the workpiece and used. When the tape is unwound from the wound body, static electricity is generated. As described above, the workpiece processing tape of the present invention has a product (Rv × Rs) of the volume resistivity Rv and the surface resistivity Rs of 10 30 Ω 2·cm / sq. or less. In other words, when the volume resistivity Rv is high, the surface resistivity Rs is low, and static electricity is discharged by surface conduction. Also, when the surface resistivity Rs is high, the volume resistivity Rv is low, and static electricity is discharged by bulk conduction. Therefore, even if static electricity is generated when unwinding the tape from the winder, the bulk conduction that travels within the tape in a direction perpendicular to the tape thickness, and the bulk conduction that travels within the tape in the tape thickness direction and conduction on the tape surface work effectively, allowing static electricity to be discharged in a short time.

[0106] Furthermore, when a workpiece processing tape is applied to a workpiece, tension is applied to the tape. In particular, when the tape is unwound from a reel and applied to a workpiece, tension is applied both when unwound and when applied. When a workpiece processing tape is composed of a soft adhesive layer and an extremely thin surface coating layer, the application of tension can cause the workpiece processing tape to stretch and wrinkle along the stretching direction. Wrinkles in the workpiece processing tape not only result in poor appearance, but can also cause uneven adhesion between the workpiece processing tape and the workpiece when applied to the workpiece, preventing proper application. In this case, the tape must be peeled off and reapplied, reducing work efficiency.

[0107] As described above, the work processing tape of the present invention has controlled distortion when tension is applied, and therefore wrinkles are suppressed even when stretched, allowing stable application work.

[0108] (Method of manufacturing tape for work processing) Next, the methods for producing the workpiece processing tape will be explained. According to the first method, the adhesive strength of the adhesive layer surface can be set relatively high, while according to the second method, it becomes relatively low.

[0109] In the first method, as shown in FIG. 2(a), a coating layer 1 is provided on a first release film 21 to produce a first release film with a coating layer.

[0110] The release film used is a release film having at least one surface subjected to a release treatment, and specifically includes a release film having a release agent applied to the surface of a release film substrate.

[0111] The substrate for the release film is preferably a resin film, 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, and polyolefin resins such as polypropylene resin and polyethylene resin. Examples of the release agent include silicone-based release agents, alkyd-based release agents, and fluorine-based release agents.

[0112] The thickness of the release film is not particularly limited, but is preferably 10 to 200 μm, more preferably 20 to 150 μm.

[0113] The method for forming the uncured coating layer 1 on the first release film 21 is not particularly limited. The surface coating layer composition or the coating agent described below may be applied by a known method, such as spin coating, spray coating, bar coating, knife coating, roll coating, blade coating, die coating, or gravure coating. The coating layer 1 is applied to a thickness that corresponds to the thickness of the surface coating 2 after final curing, and then dried as necessary. The surface coating layer composition may be diluted with an organic solvent as needed and applied as a coating agent. Examples of organic solvents include methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexane, n-hexane, toluene, xylene, n-propanol, and isopropanol. The surface coating layer composition or the coating agent may be applied in a single step or in two or more separate steps, but a single coating layer is preferred. When the surface coating layer composition is applied two or more times, the same surface coating layer composition may be used, or surface coating layer compositions having similar compositions may be used.

[0114] Next, as shown in FIG. 2(b), the pressure-sensitive adhesive layer composition or a coating agent described below is applied to the uncured coating layer 1 of the release film with the coating layer to form an uncured pressure-sensitive adhesive layer 3. The coating method is the same as described above. The coating thickness is determined so that the final thickness after curing will be the thickness of the pressure-sensitive adhesive layer 4, and the coating may be dried as necessary. The pressure-sensitive adhesive layer composition may be diluted with an organic solvent as described above to form a coating agent, but solvent-free coating is preferable to reduce environmental impact. Coating may be performed in one step or in two or more steps, but a single uncured pressure-sensitive adhesive layer is more preferable. When the pressure-sensitive adhesive layer composition is applied two or more times, the same pressure-sensitive adhesive layer composition may be used, or compositions with similar compositions may be used.

[0115] Next, as shown in FIG. 2(c), energy rays EB are irradiated to semi-cure the energy ray-curable components contained in the surface coating layer composition and the adhesive layer composition. The energy rays are irradiated using, for example, a high-pressure mercury lamp. By simultaneously curing the uncured coating layer 1 and adhesive layer 3, the energy ray-curable components contained in the coating layer 1 and adhesive layer 3 are bonded together, improving the adhesion between the semi-cured coating layer 1 and adhesive layer 3. The amount of energy rays irradiated may be an amount that partially cures the energy ray-curable components contained in the coating layer 1 and adhesive layer 3. Ultraviolet rays are preferred as the energy rays, and their illuminance is 60 to 320 mW / cm. 2 The light intensity is preferably 30 to 1000 mJ / cm 2 It is preferable that:

[0116] If energy beam irradiation is performed in an atmospheric environment, polymerization is inhibited by oxygen, and polymerization does not proceed completely on the surface of the adhesive layer 3 that is attached to the workpiece, resulting in a relatively soft surface, allowing the adhesive strength of the adhesive layer to be set high.

[0117] 2(d), a second release film 22 is laminated on the semi-cured pressure-sensitive adhesive layer 3. The second release film may be the same as the first release film, but it is preferable to use a film that has high transmittance to energy rays.

[0118] 2(e), irradiation with energy rays EB is carried out to cure all of the energy ray-curable components contained in the coating layer 1 and the adhesive layer 3, obtaining a surface coating layer 2 from the coating layer 1, and converting the uncured adhesive layer 3 into a cured adhesive layer 4. Ultraviolet rays are preferred as the energy rays, and the illuminance thereof is 100 to 400 mW / cm. 2 The light intensity is preferably 200 to 1500 mJ / cm 2 Even if energy rays are irradiated in this state, the surface of the pressure-sensitive adhesive layer 4 that has been inhibited from polymerization will not be sufficiently hardened, and the surface will remain relatively soft and likely to maintain high adhesive strength.

[0119] After the above steps, the first release film is peeled off to obtain a laminate (i.e., a workpiece processing tape with a release film) in which the second release film is laminated on the workpiece processing tape 10 having the configuration shown in Figure 1.

[0120] In the second manufacturing method, polymerization inhibition on the surface of the adhesive layer to be attached to the workpiece is avoided, and the surface of the adhesive layer can be set to be relatively hard and low in adhesive strength.

[0121] In the second method, as shown in Fig. 3(a), the composition for the pressure-sensitive adhesive layer is applied onto a second release film 22 to form an uncured pressure-sensitive adhesive layer 3. The application method and coating thickness are the same as those in the first method.

[0122] Next, as shown in Fig. 3(b), energy rays are irradiated to semi-cure the energy ray-curable component contained in the composition for pressure-sensitive adhesive layer. The energy rays are preferably ultraviolet rays, and the irradiance thereof is 60 to 320 mW / cm 2 The light intensity is preferably 30 to 1000 mJ / cm 2 If the energy beam irradiation is performed in the air, polymerization inhibition occurs due to oxygen. However, as will be described later, the soft surface formed by the polymerization inhibition forms a surface coating layer 2, and is not used as an adhesive surface to be attached to a workpiece.

[0123] Separately from the above, an uncured coating layer 1 is provided on a first release film 21 to prepare a first release film with a coating layer.

[0124] 3(c), the coating layer 1 of the first release film with a coating layer is laminated on the semi-cured pressure-sensitive adhesive layer 3. It is preferable to use a film that has high transmittance to energy rays as the first release film.

[0125] Next, as shown in FIG. 3(d), energy rays are irradiated to cure the energy ray curable components contained in the surface coating layer composition and the pressure-sensitive adhesive layer composition. The unreacted energy ray curable components in the semi-cured pressure-sensitive adhesive layer 3 and the energy ray curable components contained in the uncured coating layer 1 are polymerized and cured, obtaining a surface coating layer 2 from the coating layer 1, and converting the uncured pressure-sensitive adhesive layer 3 into a cured pressure-sensitive adhesive layer 4. Ultraviolet rays are preferred as the energy rays, and the illuminance thereof is 100 to 400 mW / cm. 2 The light intensity is preferably 200 to 1500 mJ / cm 2 After curing, the adhesiveness between the surface coating layer and the pressure-sensitive adhesive layer 4 is improved due to the curing of the energy ray-curable component.

[0126] After the above steps, the first release film is peeled off to obtain a laminate (i.e., a workpiece processing tape with a release film) in which the second release film is laminated on the workpiece processing tape 10 having the configuration shown in Figure 1.

[0127] The obtained workpiece processing tape may be cut in advance to fit the shape of the workpiece to be attached and formed into sheets, or may be wound into a roll to form a wound body. The workpiece processing tape of the present invention can quickly discharge static electricity generated when the tape is unwound from the winding body, and can effectively suppress the occurrence of wrinkles caused by tension when the tape is unwound from the winding body.

[0128] (Control of distortion, volume resistivity Rv, and surface resistivity Rs of tape for workpiece processing) The strain is likely to be reduced by increasing the number of crosslinked structures contained in the pressure-sensitive adhesive layer 4 (for example, by increasing the number of (meth)acryloyl groups per molecule of the urethane (meth)acrylate (d1) in the pressure-sensitive adhesive layer composition, by selecting a urethane (meth)acrylate (d1) with a smaller weight-average molecular weight among urethane (meth)acrylates (d1) having the same number of (meth)acryloyl groups per molecule, or by increasing the amount of the polyfunctional energy ray-curable compound (d2)).The strain is likely to be reduced by using a compound having a relatively rigid alicyclic group or heterocyclic group as the energy ray-curable compound (d3) having an alicyclic group or heterocyclic group with 6 to 20 ring atoms (more specifically, a compound that, when a homopolymer is produced by polymerizing the compound (d3) as a monomer, produces a homopolymer with a high glass transition temperature). In addition, by increasing the content of the photopolymerization initiator in the composition for the pressure-sensitive adhesive layer or by increasing the illuminance or light amount in the energy ray irradiation, the distortion can be reduced compared to when there is a small amount of photopolymerization initiator or when the energy ray irradiation conditions are weak.

[0129] The volume resistivity of the workpiece processing tape can be controlled by adjusting the amount of antistatic agent contained in the pressure-sensitive adhesive layer composition and the pressure-sensitive adhesive layer 4. Furthermore, by increasing the amount of relatively highly polar functional groups (e.g., hydroxyl groups, carboxyl groups, amide groups, amino groups, etc.) contained in the pressure-sensitive adhesive layer 4, the volume resistivity Rv of the workpiece processing tape tends to decrease.

[0130] In addition, the surface resistivity Rs of the surface coating layer can easily be reduced by including an antistatic agent in the surface coating layer composition and the surface coating layer 2. However, as mentioned above, in a work processing tape that essentially consists of two layers, a surface coating layer and an adhesive layer, the influence of the thick adhesive layer is greater than that of the thin surface coating layer, so the surface coating layer composition does not essentially need to include an antistatic agent.

[0131] (Workpiece processing method) The workpiece processing tape of the present invention is used to temporarily protect and hold various workpieces such as semiconductor wafers when they are subjected to processing such as backside grinding. The workpiece processing tape of the present invention is preferably used to protect the surface of the workpiece by being attached to the surface of the workpiece when backside grinding is performed.

[0132] As a non-limiting example of the use of the workpiece processing tape, a method for grinding the backside of a workpiece will be described in more detail, in which the workpiece is a wafer and the processing includes grinding the backside.

[0133] Specifically, the method for grinding the back surface of a workpiece (wafer) includes at least the following steps 1 to 3. Step 1: A process of applying the above work processing tape to the surface of the wafer. Process 2: The wafer with workpiece processing tape attached to its surface is ground from the back side. Step 3: The workpiece processing tape is removed from the wafer after backside grinding.

[0134] Each step of the above-described wafer back grinding method will now be described in detail.

[0135] (Process 1) In step 1, as shown in Fig. 4, the adhesive layer 4 of the workpiece processing tape 10 according to this embodiment is applied to the surface 12a of a wafer 12 serving as a workpiece. By applying the workpiece processing tape to the surface of the wafer, the surface of the wafer is adequately protected. If the workpiece processing tape has been stored as a roll, it is applied to the wafer while being unwound from the roll.

[0136] The thickness of the wafer before grinding is not particularly limited, but is usually about 500 to 1000 μm. Furthermore, the wafer usually has a circuit formed on its surface. Formation of the circuit on the wafer surface can be performed by various methods, including conventionally widely used methods such as etching and lift-off.

[0137] The wafer with the workpiece processing tape attached is placed on a suction table (an example of a work table) and is held by suction on the suction table. At this time, the surface coating layer side of the workpiece processing tape is placed on the table side and is suctioned.

[0138] (Process 2) After step 1, the backside of the wafer on the suction table is ground to obtain a back-ground wafer. In this embodiment, the thickness of the wafer after back-ground is not particularly limited, but may be, for example, 200 μm or less, or 100 μm or less. When the thickness of the wafer after back-ground is within the above range, miniaturization and thinning of the chip can be easily achieved.

[0139] (Step 3) Next, the workpiece processing tape 10 is peeled off from the wafer. This step is carried out, for example, by the following method.

[0140] After back grinding, another tape, such as dicing tape or dual-purpose dicing / die bond tape, is applied to the backside of the wafer. At this time, the outer edge of the other tape is fixed to a ring frame (not shown). Next, the workpiece processing tape 10 is peeled off from the wafer held on the other tape. To peel off the workpiece processing tape 10, the peeling tape, which serves as the starting point for peeling, is pressed against the surface coating layer 2 of the workpiece processing tape, and the peeling tape is pulled up in the folding direction to peel off the workpiece processing tape 10.

[0141] The workpiece processing tape according to this embodiment has the above-described characteristics, and therefore even if static electricity is generated when the tape is unwound, it is quickly discharged, preventing damage to the workpiece due to static electricity, stably holding and protecting the wafer, and suppressing the occurrence of wrinkles when the tape is stretched to be attached to the workpiece, allowing for stable attachment work.

[0142] The workpiece processing tape according to the present invention can also be suitably used in a method for producing individual pieces (chips) using a pre-dicing method.

[0143] In addition to steps 1 to 3 above, the chip manufacturing method using the pre-dicing method includes a step (step 4) of forming a groove from the front surface side of the wafer, or forming a modified region inside the wafer from the front or back surface of the wafer.

[0144] When forming a modified region on a wafer, it is preferable to perform step 1 before step 4. On the other hand, when forming grooves on the wafer surface by dicing or the like, step 1 is performed after step 4. That is, in step 1, a workpiece processing tape is attached to the surface of the wafer having the grooves formed in step 4, which will be described later.

[0145] In step 4, a groove is formed from the front surface side of the wafer, or a modified region is formed inside the wafer from the front surface or rear surface of the wafer.

[0146] The grooves formed in this step are shallower than the thickness of the wafer. The grooves can be formed by dicing using a conventionally known wafer dicing device. The grooves are the starting points for dividing the wafer into individual pieces along the grooves by back grinding in step 2 described above.

[0147] The modified region is a brittle part of the wafer, and is the starting point for breaking the modified region of the wafer and dividing it into individual pieces when the wafer is thinned by grinding in the grinding process or when grinding force is applied. That is, in step 4, the grooves and modified region are formed along the dividing lines when the wafer is divided into individual pieces in step 2 described above.

[0148] The modified region is formed by irradiating the wafer with a laser focused on the interior of the wafer, and the modified region is formed inside the wafer. The laser irradiation may be performed from the front side or the back side of the wafer. In the embodiment in which the modified region is formed, if step 4 is performed after step 1 and the laser irradiation is performed from the front side of the wafer, the laser is irradiated onto the wafer through the workpiece processing tape.

[0149] In the first-dicing method, if grooves are to be formed in the wafer, back grinding in step 2 is performed so as to thin the wafer at least to the position that reaches the bottom of the grooves. This back grinding turns the grooves into cuts that penetrate the wafer, and the wafer is divided into individual pieces by the cuts.

[0150] On the other hand, if a modified region is formed, the grinding surface (wafer back surface) may reach the modified region by grinding, but it does not have to reach the modified region exactly. In other words, grinding should be performed to a position close to the modified region so that the wafer is broken and divided into individual pieces starting from the modified region. The workpiece processing tape can be peeled off from the divided wafer (i.e., the aligned multiple chips) in the same manner as in step 3 above.

[0151] The workpiece processing tape of the present invention can also be used as a dicing tape for fixing a workpiece during blade dicing using a rotary blade.

[0152] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and may be modified in various ways within the scope of the present invention. [Example]

[0153] The present invention will be described in more detail below using examples, but the present invention is not limited to these examples.

[0154] The measurement and evaluation methods in this example are as follows: When the prepared tape is a workpiece processing tape with a release film, the release film is removed before measuring the strain, volume resistivity, surface resistivity, and adhesive strength.

[0155] (strain) Strain measurements are performed in accordance with JIS K 7161. Specifically, a strip-shaped measurement sample, cut from workpiece processing tape to a width of 15 mm and a length of 150 mm, is attached to a precision universal testing machine and stretched at a rate of 200 mm / min. Strain (%) is calculated from the amount of elongation at the point where the tensile force reaches 2.5 N / 15 mm. Measurements are performed at a chuck distance (i.e., initial sample length) of 100 mm, at 23°C, and at a relative humidity of 50%. Strain (%) is calculated by determining the elongation Δ, which is the difference between the sample length (chuck distance) at the point where the tensile force reaches 2.5 N / 15 mm and the initial sample length (100 mm). The ratio of elongation Δ to the initial sample length (100 mm) [= (Δ / 100) × 100] is defined as strain (%).

[0156] (Volume resistivity Rv) The volume resistivity Rv of the workpiece processing tape was measured in accordance with JIS K6911-1995 by cutting the workpiece processing tape into a 10 cm x 10 cm piece and using the double ring electrode method (two-terminal method). The measuring equipment used was an Advantest resistance meter (Digital Electrometer R8252) and an Advantest sample chamber TR42. The measurement was performed in an environment of 23°C and 50% RH, and the volume resistivity was calculated based on the current value when a voltage of 100 V was applied for 1 minute.

[0157] (Surface resistivity Rs) The surface resistivity Rs of the surface coating layer was measured in accordance with JIS K6911-1995 using a double ring electrode method (two-terminal method) on a 10cm x 10cm piece of workpiece processing tape. The measuring equipment used was an Advantest resistance meter (Digital Electrometer R8252) and an Advantest sample chamber TR42. The measurement was performed in an environment of 23°C and 50% RH, and the surface resistivity was calculated based on the current value when a voltage of 100V was applied for 1 minute.

[0158] (Adhesive strength) Adhesive strength is measured in accordance with JIS Z 0237. Specifically, the adhesive layer of a strip-shaped measurement sample, cut from workpiece processing tape to a width of 25 mm, is applied to a silicon wafer (thickness: 700 μm, diameter: 200 mm) with a 2 kg roller at 23°C and 50% relative humidity. After 20 minutes, the adhesive strength is measured by peeling the sample at a speed of 300 mm / min in a 180° direction using a universal (peel load) tester, Tensilon (manufactured by A&D Co., Ltd.). A mirror-finished silicon wafer with a surface roughness Ra of 5 nm ± 2 nm is used, and the workpiece processing tape is applied to the mirror-finished surface to measure adhesive strength. The measurement length is 70 mm, and the measurements at the first 10 mm and the last 10 mm are excluded from the valid values. The average value of the measured values ​​was taken as the adhesive strength (mN / 25 mm), and the adhesive strength was measured twice, and the average value was used.

[0159] (Evaluation of tape discharge when unwinding (static electricity measurement)) A workpiece processing tape (length: 5 m) with a release film, prepared by the method described below, was wound around a plastic core (made of ABS, inner diameter: 3 inches) to obtain a roll. The roll was wound so that the surface coating layer was on the surface side of the roll. In this state, the roll was left to stand and statically discharged until any static electricity remaining on the roll was negligible. The tape was then unwound from the roll using the unwinding mechanism of a Lintec Corporation BG tape laminator (RAD-3510F / 12), and the amount of static electricity on the surface coating layer side was measured immediately after unwinding (0 seconds), and at 10, 30, 60, and 120 seconds after unwinding. Measurement equipment: Non-contact ESD measuring device (Field Meter Set PFK-100), measurement was performed 3 cm away from the measurement surface.

[0160] (Evaluation of tape deformation when tape is applied) Using a Lintec backing tape laminator (RAD-3510F / 12), tape was unwound from a roll of workpiece processing tape with a release film, prepared as described below. The unwound tape was moved to the suction table in the tape laminator on which a silicon wafer (thickness: 700 μm, diameter: 200 mm) was placed, the release film was removed, and the tape was applied to the mirror-finished silicon wafer (tension setting of the tape laminator during application: 7.0 N). The condition of the tape immediately before application to the silicon wafer was visually inspected and evaluated according to the following criteria. A: No wrinkles B: Minor wrinkles occur that allow application (1-2 visible wrinkles) C: Unable to apply (3 or more visible wrinkles)

[0161] (Preparation of urethane acrylate oligomer (component (d1))) A bifunctional urethane acrylate oligomer was prepared as a component of the pressure-sensitive adhesive layer composition. The urethane acrylate oligomer was obtained by reacting 2-hydroxyethyl acrylate with a urethane prepolymer terminated with an isocyanate derived from isophorone diisocyanate, which was obtained by reacting polypropylene glycol with isophorone diisocyanate. The weight ratio (polypropylene glycol / isophorone diisocyanate / 2-hydroxyethyl acrylate) was 4 / 5 / 2. The weight-average molecular weight of the obtained urethane acrylate oligomer was 8,600.

[0162] (Preparation of Composition for Pressure-Sensitive Adhesive Layer) The urethane acrylate oligomer synthesized above, isobornyl acrylate (IBXA), 2-hydroxy-2-methyl-1-phenyl-1-propanone (IGM Resins, product name "Omnirad 1173") as a photopolymerization initiator, and ionic liquid (Nippon Nyukazai, product name "Aminoion (registered trademark) RE3000MF") as an antistatic agent were blended in the amounts shown in the table below to prepare a pressure-sensitive adhesive layer composition, which was used to produce each of the workpiece processing tapes of the Examples and Comparative Examples.

[0163] [Table 1]

[0164] (Preparation of Composition for Surface Coating Layer) 100 parts by mass of epoxy acrylate resin (manufactured by Arkema, product name "CN104 NS"), 30 parts by mass of silica filler (manufactured by Nissan Chemical Industries, Ltd., product name "Snowtex (registered trademark) UP"), and 5 parts by mass of 1-hydroxycyclohexyl phenyl ketone (manufactured by IGM Resins, product name "Omnirad (registered trademark) 184") as a photopolymerization initiator were dissolved and dispersed in toluene to an active ingredient concentration of 5% by mass, thereby obtaining a coating agent for a surface coating layer composition.

[0165] (Measurement of storage modulus (E') of surface coating layer) The coating agent of the surface coating layer composition was applied to the release-treated surface of a process release film (manufactured by Lintec Corporation, product name "SP-PET381031", a silicone release-treated polyethylene terephthalate (PET) film, thickness: 38 μm), and dried at 100°C for 2 minutes to form an uncured coating layer. 2 , light intensity 700mJ / cm 2 The coating layer was cured by irradiation with ultraviolet light (UV light) to obtain a surface coating layer sample (55 μm thick) for measuring the storage modulus (E'). The surface coating layer sample was cut into a width of 4 mm, and the release film for the process was removed. The storage modulus (E') of the surface coating layer sample was measured using a dynamic viscoelasticity measuring device (RHEOVIBRON DDV-01FP, manufactured by A&D Corporation) under the following conditions: tension mode, sample length of the measurement section 20 mm, temperature -30°C to 120°C, temperature increase 3°C / min, and measurement frequency 1 Hz. The storage modulus (E') at 23°C was read from the measured value, and the storage modulus (E') of the surface coating layer was found to be 92 MPa.

[0166] (Manufacturing tape for work processing) The workpiece processing tapes of the examples and comparative examples were produced by the following method.

[0167] As shown in Figure 2(a), a coating agent of a surface coating layer composition was applied to the release-treated surface of a first release film 21 (manufactured by Lintec Corporation, product name "SP-PET381031", a polyethylene terephthalate (PET) film with silicone release treatment, thickness: 38 μm), and dried to form an uncured coating layer.

[0168] Next, as shown in FIG. 2(b), the composition for pressure-sensitive adhesive layer was applied onto the coating layer 1 of the release film with the coating layer to form an uncured pressure-sensitive adhesive layer 3.

[0169] Next, as shown in Figure 2(c), energy rays (illuminance 130 mW / cm 2 , light intensity 50mJ / cm 2 The composition was then irradiated with ultraviolet light (ultraviolet rays) to semi-cure the energy ray-curable components contained in the surface coating layer composition and the pressure-sensitive adhesive layer composition.

[0170] Next, as shown in FIG. 2(d), a second release film 22 (manufactured by Lintec Corporation, trade name "SP-PET381031") was laminated on the semi-cured pressure-sensitive adhesive layer 3.

[0171] Furthermore, as shown in Figure 2(e), energy rays (illuminance 350 mW / cm 2 , light intensity 700mJ / cm 2 The coating layer 1 was irradiated with energy ray-curable ultraviolet light (ultraviolet rays) to cure all of the energy ray-curable components contained in the adhesive layer 3, resulting in a surface coating layer 2 (thickness: 2 μm) from the coating layer 1, and the uncured adhesive layer 3 was converted into a cured adhesive layer 4 (thickness: 123 μm). The first release film 21 was removed to obtain a workpiece processing tape 10 (i.e., a workpiece processing tape with a release film) having the configuration shown in FIG. 1 with a second release film 22 laminated thereon.

[0172] The adhesive strength, distortion, volume resistivity, and surface resistivity of each workpiece processing tape obtained above were measured, and the discharge properties of the tape when unwound (static electricity measurement) and the deformation properties when the tape was applied were evaluated. The results are shown in the table below. The workpiece processing tape of Comparative Example 2 was unable to be applied due to excessive distortion.

[0173] [Table 2] [Industrial Applicability]

[0174] As shown in Table 2, the workpiece processing tape of the present invention suppresses the occurrence of wrinkles even when stretched, allowing for stable application. Furthermore, even if static electricity is generated when the tape is unwound, it is quickly discharged, preventing damage to the workpiece due to static electricity. [Explanation of symbols]

[0175] 10...Tape for work processing 1...Uncured coating layer 2...hardened coating layer 3...Uncured adhesive layer 4...Cured adhesive layer 12...Workpiece (wafer) 12a...surface of work (circuit surface of wafer) 21...First release film 22...Second release film

Claims

1. A work processing tape essentially consisting of two layers: a surface coating layer and a pressure-sensitive adhesive layer, When a tensile test of the workpiece processing tape is carried out at 23°C, the strain from the start of tension until a tensile force of 2.5 N / 15 mm is reached is 20% or less, The product of the volume resistivity Rv (unit: Ω cm) of the workpiece processing tape and the surface resistivity Rs (unit: Ω / sq.) of the surface coating layer is 10 30 Ω 2 cm / sq. or less, Tape for work processing.

2. The volume resistivity Rv of the workpiece processing tape is 10 15 2. The tape for workpiece processing according to claim 1, wherein the tape has a hardness of Ω·cm or less.

3. The surface resistivity Rs of the surface coating layer is 10 15 2. The tape for workpiece processing according to claim 1, wherein the hardness is Ω / sq. or less.

4. 2. The tape for workpiece processing according to claim 1, wherein the adhesive strength of the adhesive layer is 700 mN / 25 mm or more.

5. 2. The workpiece processing tape according to claim 1, wherein the thickness of the adhesive layer is 90 [mu]m or more.

6. 2. The tape for workpiece processing according to claim 1, wherein the thickness of the surface coating layer is 0.2 to 5 μm.

7. 2. The workpiece processing tape according to claim 1, wherein the adhesive layer is a cured product of an adhesive layer composition containing an energy ray-curable compound.

8. 2. The workpiece processing tape according to claim 1, wherein the adhesive layer contains an antistatic agent.

9. The tape for workpiece processing according to claim 8 , wherein the antistatic agent contains an ionic liquid.

10. A workpiece processing tape wound body, which is obtained by winding the workpiece processing tape according to any one of claims 1 to 9 into a roll.

11. A method for producing a laminate of a workpiece and a tape for workpiece processing, comprising a step of applying an adhesive layer of the tape for workpiece processing according to any one of claims 1 to 9 to the surface of the workpiece.

12. A method for manufacturing a laminate of a workpiece and a tape for workpiece processing, comprising the steps of unwinding the tape from a roll of the tape for workpiece processing according to claim 10 and applying the adhesive layer of the tape to the surface of the workpiece.

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