TW202137306A - Protection sheet for semiconductor processing and manufacturing method of semiconductor device can suppress the generation of cracks in the wafer after polishing - Google Patents

Abstract

The present invention provides a protection sheet for semiconductor processing that can fully follow the unevenness of the wafer even when a semiconductor wafer having unevenness is thinned by DBG, etc., and can suppress the generation of cracks in the wafer after polishing. The protection sheet for semiconductor processing has a substrate, and has an intermediate layer and an adhesive layer sequentially on one main surface of the substrate. It satisfies the following (a) and (b): (a) The loss tangent of the intermediate layer at 50 DEG C measured at a frequency of 1 Hz is 0.40 or more and 0.65 or less; (b) The ratio [A/I] of the storage modulus A of the adhesive layer to the storage modulus I of the intermediate layer at 50 DEG C measured at a frequency of 1 Hz is 0.80 or more and 3.50 or less.

Description

Protective sheet for semiconductor processing and manufacturing method of semiconductor device

The present invention relates to a protective sheet for semiconductor processing and a method of manufacturing a semiconductor device. In particular, it relates to a protection sheet for semiconductor processing suitable for a method of polishing the back surface of a semiconductor wafer with unevenness and singulation of the semiconductor wafer using grinding stress or the like, and a semiconductor device using the protection sheet for semiconductor processing的制造方法。 Manufacturing method.

In the process of miniaturization and multi-functionalization of various electronic devices, the semiconductor chips mounted in these devices are also required to be miniaturized and thinner. In order to reduce the thickness of the wafer, the back surface of the semiconductor wafer is usually polished to adjust the thickness. In addition, in order to obtain thinner wafers, a process method called Dicing Before Grinding (DBG) is sometimes used, which uses a dicing blade to form grooves of a predetermined depth from the surface of the wafer. The back side of the circle is polished, and the wafer is singulated by polishing to obtain a wafer. DBG can simultaneously perform back grinding of wafers and singulation of wafers, so thin wafers can be manufactured efficiently.

In the past, when performing back grinding of a semiconductor wafer, or when manufacturing a wafer by DBG, in order to protect the circuit on the surface of the wafer, or to hold the semiconductor wafer and the semiconductor wafer, it is usually called back grinding. Piece of adhesive tape.

As the back grinding sheet used in DBG, an adhesive tape having 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, Patent Document 1 and Patent Document 2 disclose an adhesive tape having a substrate with a high Young's modulus, and a buffer layer is provided on one surface of the substrate, and on the other An adhesive layer is provided on the surface.

In recent years, as a modified example of the pre-dicing method, a method has been proposed in which a modified region is provided inside the wafer by using a laser, and the wafer is singulated by the stress and the like when the backside of the wafer is polished. Hereinafter, this method may be described as LDBG (Laser Dicing Before Grinding (Laser Dicing Before Grinding)). In LDBG, the wafer is cut along the crystallographic direction from the modified region as a starting point. Therefore, chipping can be reduced more than the pre-cut method using a dicing knife. As a result, a wafer with excellent flexural strength can be obtained, and it can contribute to further thinning of the wafer. In addition, compared with DBG that uses a dicing knife to form grooves of a predetermined depth on the surface of the wafer, since there is no area where the wafer is cut off with a dicing knife, that is, the cut width is extremely small, the yield of the wafer is excellent.

On the other hand, when mounting multi-pin LSI packages for MPUs or gate arrays on printed wiring boards, flip-chip mounting methods have been used. In this mounting method, semiconductor chips are used in their pads. The part is formed with bumps (bumps) made of eutectic solder, high-temperature solder, gold, etc., and these bumps are aligned with those on the substrate for chip mounting by a so-called face-down method The terminal parts of the two are facing and contacting each other, and are melted and diffusion bonded. [Prior Art Literature] [Patent Literature]

Patent Document 1: International Publication No. 2015/156389 Patent Document 2: Japanese Patent Application Publication No. 2015-183008

[Technical Problem to be Solved by the Invention]

The semiconductor wafer used in this mounting method is obtained by singulating a semiconductor wafer having concavities and convexities such as a semiconductor wafer on which convex electrodes are formed. When the semiconductor wafer with unevenness is polished by DBG, as described above, in order to protect the circuit surface during polishing and prevent wafer movement after the wafer is singulated, it will be attached to the circuit surface of the semiconductor wafer. Comes with back grinding tape.

However, when the back grinding tape described in Patent Document 1 and Patent Document 2 is attached to the circuit surface of a semiconductor wafer having unevenness and is polished by DBG, the back grinding tape described in Patent Document 1 and Patent Document 2 The unevenness of the semiconductor wafer cannot be fully followed, and there are problems such as water intruding into the circuit surface during polishing, and wafer movement (wafer displacement) after the wafer is singulated.

The present invention was completed in view of the above circumstances, and its object is to provide a protective sheet for semiconductor processing that can fully follow the unevenness of the wafer even when thinning a semiconductor wafer having unevenness by DBG or the like, and can suppress the occurrence of cracks in the wafer after polishing. . [Technical means to solve technical problems]

The mode of the present invention is as follows. [1] A protective sheet for semiconductor processing, which has a substrate, and has an intermediate layer and an adhesive layer in this order on one main surface of the substrate, and satisfies the following (a) and (b): (a) The loss tangent of the intermediate layer at 50°C measured at a frequency of 1 Hz is 0.40 or more and 0.65 or less; (b) The ratio [A/I] of the storage modulus A of the adhesive layer to the storage modulus I of the intermediate layer at 50°C measured at a frequency of 1 Hz is 0.80 or more and 3.50 or less.

[2] The protective sheet for semiconductor processing according to [1], which has a buffer layer on the other main surface of the base material.

[3] The protective sheet for semiconductor processing according to [1] or [2], wherein the Young's modulus of the substrate is 1000 MPa or more.

[4] The protective sheet for semiconductor processing according to any one of [1] to [3], wherein the thickness of the intermediate layer is 60 μm or more and 250 μm or less.

[5] The protective sheet for semiconductor processing according to any one of [1] to [4], wherein the adhesive layer is energy ray curable.

[6] The protective sheet for semiconductor processing according to any one of [1] to [5], wherein the intermediate layer is energy ray curable.

[7] The protective sheet for semiconductor processing according to any one of [1] to [6], wherein the back surface of the semiconductor wafer having grooves formed on the surface of the semiconductor wafer is polished and the polishing is performed In the step of singulating the semiconductor wafer into a semiconductor wafer, the protective sheet for semiconductor processing is attached to the surface of the semiconductor wafer and used.

[8] A method of manufacturing a semiconductor device, including: A step of attaching the protective sheet for semiconductor processing according to any one of [1] to [7] to the surface of a semiconductor wafer having unevenness; The step of forming a trench from the surface side of the semiconductor wafer, or the step of forming a modified region inside the semiconductor wafer from the surface or back of the semiconductor wafer; A step of polishing a semiconductor wafer with a protective sheet for semiconductor processing attached on the surface and formed with grooves or modified regions from the back side, and singulated into multiple wafers with the grooves or modified regions as the starting point; and The step of peeling the protective sheet for semiconductor processing from the singulated semiconductor wafer. [Effects of the invention]

According to the present invention, it is possible to provide a protective sheet for semiconductor processing that can sufficiently follow the unevenness of the wafer even when the semiconductor wafer is thinned by DBG or the like, and can suppress the generation of cracks in the wafer after polishing.

Hereinafter, based on specific embodiments, the present invention will be described in detail using drawings. First, the main terms used in this specification are explained.

The singulation of a semiconductor wafer refers to dividing the semiconductor wafer for each circuit to obtain a semiconductor wafer.

The “surface” of a semiconductor wafer refers to the surface on which circuits, electrodes, etc. are formed, and the “back surface” refers to the surface on which circuits, etc. are not formed.

DBG refers to a method in which a groove of a predetermined depth is formed on the surface side of a wafer, and then polished from the back side to singulate the wafer by polishing. The grooves formed on the surface side of the wafer can be formed by methods such as blade dicing, laser dicing, or plasma dicing.

In addition, LDBG is a modified example of DBG, which refers to a method in which a modified region is provided inside the wafer by using a laser, and the wafer is singulated using stress and the like when the backside of the wafer is polished.

The "chipset" refers to a plurality of semiconductor wafers held on the protective sheet for semiconductor processing of the present invention after semiconductor wafers are singulated. These semiconductor wafers as a whole constitute the same shape as that of the semiconductor wafer.

In this specification, for example, "(meth)acrylate" is used as a term representing "acrylate" and "methacrylate", and other similar terms are also the same.

"Energy rays" refer to ultraviolet rays, electron beams, etc., and ultraviolet rays are preferred.

(1. Protective sheet for semiconductor processing) As shown in FIG. 1A, the protective sheet 1 for semiconductor processing of the present embodiment has a structure in which an intermediate layer 20 and an adhesive layer 30 are sequentially stacked on a substrate 10.

The protective sheet for semiconductor processing of this embodiment is used by being attached to a semiconductor wafer having unevenness. As a semiconductor wafer having unevenness, for example, a semiconductor wafer in which convex electrodes are formed can be exemplified.

For example, as shown in FIG. 2, the semiconductor processing protective sheet 1 of this embodiment is used in a manner that the main surface 30a of the adhesive layer is attached to the bump formation surface 101a of the bumped semiconductor wafer. In the semiconductor wafer with bumps, bumps 102 as bump electrodes are formed on the semiconductor wafer 101. The bumps are formed so as to be electrically connected to the circuits formed on the semiconductor wafer, so the bump formation surface 101a is the circuit surface.

In this embodiment, the bumped semiconductor wafer is singulated into a plurality of semiconductor wafers by DBG or LDBG. That is, before or after attaching the protective sheet for semiconductor processing, a groove is formed on the surface (circuit surface) or a modified region is formed inside the semiconductor wafer, and then the protective sheet for semiconductor processing is attached to the circuit surface. The surface of the semiconductor wafer opposite to the circuit surface, that is, the back surface is polished.

When unevenness such as a convex electrode is formed on a semiconductor wafer, if the thickness of the semiconductor wafer is reduced by polishing, the size of the unevenness relatively increases with respect to the thickness of the semiconductor wafer. Therefore, when the unevenness is not properly embedded in the protective sheet for semiconductor processing, the following problems become more obvious due to DBG or LDBG. That is, when the back surface is polished, water penetrates the circuit surface of the semiconductor wafer, the adhesive remains on the notch when the protective sheet for semiconductor processing is peeled off after polishing, and the singulated wafers move after polishing, causing the wafers to collide with each other and then on the wafer. Problems such as cracks on the surface become obvious.

Since the protective sheet for semiconductor processing of this embodiment has an intermediate layer and an adhesive layer mentioned later, the occurrence of the above-mentioned problems can be effectively suppressed.

The protective sheet for semiconductor processing is not limited to the structure described in FIG. 1A, and may have other layers as long as the effects of the present invention can be obtained. That is, as long as the substrate, the intermediate layer, and the adhesive layer are laminated in this order, for example, another layer may be formed between the substrate and the intermediate layer, or another layer may be formed between the intermediate layer and the adhesive layer.

In particular, in the present embodiment, as shown in FIG. 1B, it is preferable to have the buffer layer 40 on the main surface of the substrate 10 on the opposite side to the main surface on which the adhesive layer 30 is formed. By having the buffer layer 40, the occurrence of the above-mentioned problems can be further suppressed.

Hereinafter, the components of the protective sheet 1 for semiconductor processing shown in FIG. 1B will be described in detail.

(2. Substrate) The substrate is not limited as long as it is made of a material that can support a semiconductor wafer. For example, various resin films used as the base material of a back grinding tape can be illustrated. The substrate may be composed of a single-layer film composed of a single resin film, or may be composed of a multilayer film in which a plurality of resin films are laminated.

(2.1 Physical properties of the substrate) In this embodiment, the base material preferably has high rigidity. Due to the high rigidity of the substrate, even if the thickness of the semiconductor wafer is reduced by grinding, the wafer can be maintained without wafer damage. Specifically, the Young's modulus of the substrate is preferably 1000 MPa or more, more preferably 1500 MPa or more, and even more preferably 2000 MPa or more.

In this embodiment, the thickness of the substrate is preferably 15 μm or more and 200 μm or less, and more preferably 40 μm or more and 150 μm or less.

(2.2 Material of base material) As the material of the base material, a material having a Young's modulus of the base material in the above-mentioned range is preferable. In this embodiment, for example, polyesters such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, and wholly aromatic polyesters, and polyamides can be cited. Amine, polycarbonate, polyacetal, modified polyphenylene ether, polyphenylene sulfide, polysulfide, polyetherketone, biaxially stretched polypropylene, etc. Among them, polyester is preferred, and polyethylene terephthalate is more preferred.

(3. Middle layer) The intermediate layer is a layer arranged between the base material and the adhesive layer. In this embodiment, the intermediate layer and the adhesive layer can fully follow the unevenness formed on the surface of the semiconductor wafer, and the unevenness can be buried in the adhesive layer and the intermediate layer. As a result, even when the semiconductor wafer is polished very thin and a force is applied to the convex electrode or the like, the adhesive layer and the intermediate layer can sufficiently protect the convex electrode and the like. In addition, when the convex electrode etc. penetrate the adhesive layer, the intermediate layer will bury the convex electrode for protection. The intermediate layer may be composed of one layer (single layer), or may be composed of multiple layers of two or more layers.

The thickness of the intermediate layer 20 can be set in consideration of the size of the unevenness of the semiconductor wafer, for example, the height of the convex electrode. In this embodiment, the thickness of the intermediate layer 20 is preferably 60 μm or more and 250 μm or less, and more preferably 100 μm or more and 200 μm or less. In addition, the thickness of the intermediate layer means the thickness of the entire intermediate layer. For example, the thickness of the intermediate layer composed of multiple layers means the total thickness of all the layers constituting the intermediate layer.

In this embodiment, the intermediate layer has the following physical properties.

(3.1 Loss tangent at 50℃) In this embodiment, the loss tangent (tan δ) of the intermediate layer at 50°C is in the range of 0.40 or more and 0.65 or less. The loss tangent is defined as "loss modulus/storage modulus", which is a value measured in response to the stress applied to the object using a dynamic viscoelasticity measuring device.

By setting the loss tangent of the intermediate layer at 50°C to 0.40 or more, the unevenness formed on the wafer surface is sufficiently buried in the protective sheet for semiconductor processing, so that water ingress during polishing can be suppressed. In addition, by setting the loss tangent of the intermediate layer at 50°C to 0.65 or less, it is possible to suppress wafer displacement after wafer singulation.

In addition, in the present embodiment, when the intermediate layer has energy ray curability, the loss tangent of the intermediate layer at 50° C. is the loss tangent before energy ray curing.

The loss tangent of the intermediate layer at 50°C is preferably 0.42 or more. In addition, the loss tangent of the intermediate layer at 50°C is preferably 0.64 or less.

The loss tangent of the intermediate layer at 50°C may be measured by a known method. In this embodiment, the intermediate layer is made into a sample of a predetermined size, and the sample is deformed at a frequency of 1 Hz within a predetermined temperature range by a dynamic viscoelasticity measuring device, and the elastic modulus is measured. Calculate the loss tangent.

(3.2 The ratio of the storage modulus I of the intermediate layer to the storage modulus A of the adhesive layer) In this embodiment, when the storage modulus (G') of the intermediate layer at 50°C is set as the storage modulus I, and the storage modulus (G') of the adhesive layer described later is set as the storage modulus A When, the ratio "A/I" of the storage modulus I to the storage modulus A is 0.80 to 3.50.

By setting the "A/I" at 50°C to 0.80 or more, the protection sheet for semiconductor processing sufficiently follows the unevenness of the semiconductor wafer, and embedding of the unevenness of the semiconductor wafer in the protection sheet for semiconductor processing becomes appropriate. As a result, it is possible to suppress water intrusion during polishing. In addition, by setting the "A/I" at 50°C to be 3.50 or less, it is possible to prevent the adhesive from adhering to the cut when the protective sheet for semiconductor processing is peeled off.

In addition, in this embodiment, when the intermediate layer has energy ray curability, the storage modulus I is the storage modulus before energy ray curing.

The storage modulus I is not particularly limited as long as it satisfies the above-mentioned "A/I" range. In this embodiment, the storage modulus I is preferably 0.03 MPa or more and 0.08 MPa or less.

The storage modulus (storage modulus I) of the intermediate layer at 50°C may be measured by a known method. For example, the intermediate layer is made into a sample of a specified size, and the sample is deformed at a frequency of 1 Hz within a specified temperature range through a dynamic viscoelasticity measuring device, and the elastic modulus is measured. The measured elastic modulus can be calculated and stored. Modulus I.

(3.3 Composition for Intermediate Layer) As long as the intermediate layer has the above-mentioned physical properties, the composition of the intermediate layer is not particularly limited, but in this embodiment, the intermediate layer is preferably composed of a composition having a resin (composition for an intermediate layer). Specifically, it is preferable that the composition for the intermediate layer contains an acrylic polymer (A) having a weight average molecular weight of 300,000 to 1.5 million and an energy ray-curable acrylic polymer (B) having a weight average molecular weight of 50,000 to 250,000. ). The acrylic polymer (A) is non-energy ray curable or energy ray curable, but in the present embodiment, it is preferably non-energy ray curable.

In addition, in this specification, unless otherwise specified, the "weight average molecular weight" is a polystyrene conversion value measured by a gel permeation chromatography (GPC) method. As the measurement performed by this method, for example, a high-speed GPC device "HLC-8120GPC" manufactured by TOSOH is used in which high-speed chromatography columns "TSK gurd column H _XL -H", "TSK Gel GMH _XL ", "TSK Gel GMH XL" are connected in order. The equipment of "TSK Gel G2000H _XL " (all the above are made by TOSOH) uses a differential refractometer as a detector under the conditions of a column temperature of 40°C and a liquid feeding rate of 1.0 mL/min.

(3.3.1 Acrylic polymer (A)) As described above, the acrylic polymer (A) may be energy ray curable or non-energy ray curable. In this embodiment, a case where the acrylic polymer (A) is non-energy ray curable will be described. The acrylic polymer (A) is preferably a non-energy ray curable polymer having a structural unit derived from (meth)acrylate. Specifically, the acrylic polymer (A) is more preferably composed of an acrylic copolymer having a structural unit derived from an alkyl (meth)acrylate (a1) and a structural unit derived from a functional group-containing monomer (a2).

As the alkyl (meth)acrylate (a1), an alkyl (meth)acrylate whose alkyl group has 1 to 18 carbon atoms can be used. Specifically, examples include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, ( N-hexyl meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, ( N-tridecyl meth)acrylate, myristyl (meth)acrylate, palmityl (meth)acrylate, stearate (meth)acrylate, and the like.

Among them, the alkyl (meth)acrylate (a1) is preferably an alkyl (meth)acrylate having 4 to 8 carbon atoms in the alkyl group. Specifically, n-butyl (meth)acrylate is preferable. Moreover, the alkyl (meth)acrylate (a1) may be used individually by 1 type, and may be used in combination of 2 or more types.

The content of the structural unit derived from the alkyl (meth)acrylate (a1) in the acrylic polymer (A) is preferably 50 to 99.5 relative to all the structural units (100% by mass) of the acrylic polymer (A) % By mass, more preferably 60 to 99% by mass, and still more preferably 80 to 95% by mass.

If the content is 50% by mass or more, the retention performance of the adhesive sheet can be improved, and the followability to an adherend with a large unevenness can be easily improved. In addition, if it is 99.5% by mass or less, the structural unit derived from the component (a2) can be secured at a certain amount or more.

The functional group-containing monomer (a2) is a monomer having a functional group such as a hydroxyl group, a carboxyl group, an epoxy group, an amino group, a cyano group, a nitrogen atom-containing cyclic group, and an alkoxysilyl group. Among them, the functional group-containing monomer (a2) is preferably one or more selected from the group consisting of a hydroxyl group-containing monomer, a carboxyl group-containing monomer, and an epoxy group-containing monomer.

Examples of hydroxyl-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 2-hydroxypropyl (meth)acrylate. Hydroxyalkyl (meth)acrylates such as hydroxybutyl, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and unsaturated alcohols such as vinyl alcohol and allyl alcohol.

As a carboxyl group-containing monomer, (meth)acrylic acid, maleic acid, fumaric acid, itaconic acid, etc. are mentioned.

Examples of epoxy group-containing monomers include epoxy group-containing (meth)acrylates and non-acrylic epoxy group-containing monomers. Examples of epoxy group-containing (meth)acrylates include glycidyl (meth)acrylate, β-methylglycidyl (meth)acrylate, and (3,4-epoxycyclohexyl)methacrylate. (Meth)acrylate, 3-epoxycyclo-2-hydroxypropyl (meth)acrylate, etc. In addition, examples of non-acrylic epoxy group-containing monomers include glycidyl crotonic acid, allyl glycidyl ether, and the like.

The functional group-containing monomer (a2) may be used alone or in combination of two or more kinds.

Among the functional group-containing monomers (a2), carboxyl group-containing monomers are more preferred, (meth)acrylic acid is further preferred, and acrylic acid is most preferred. When a carboxyl group-containing monomer is used as the functional group-containing monomer (a2), the cohesive force of the intermediate layer is increased, and it is easy to make the retention performance of the intermediate layer and the like better.

The content of the structural unit derived from the functional group-containing monomer (a2) in the acrylic polymer (A) relative to all the structural units (100% by mass) of the acrylic polymer (A) is preferably 0.5-40% by mass, and more Preferably it is 3-20 mass %, More preferably, it is 5-15 mass %.

If the content of the structural unit derived from the component (a2) is 0.5% by mass or more, the cohesive force of the intermediate layer increases, and it is also easy to make the compatibility with the component (B) good. On the other hand, if the content is 40% by mass or less, the structural unit derived from the component (a1) can be secured at a certain amount or more.

The acrylic polymer (A) may be a copolymer of an alkyl (meth)acrylate (a1) and a functional group-containing monomer (a2), but it may also be a component (a1), a component (a2), and other than these ( a1) and (a2) a copolymer of monomers (a3) other than the components.

Examples of other monomers (a3) include cyclohexyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentyl (meth)acrylate, (Meth)acrylate, vinyl acetate, styrene, etc. which have a cyclic structure, such as dicyclopentenyl (meth)acrylate and dicyclopentenoxyethyl (meth)acrylate. The other monomers (a3) may be used alone or in combination of two or more.

The content of the structural unit derived from the other monomer (a3) in the acrylic polymer (A) is preferably 0-20% by mass relative to all the structural units (100% by mass) of the acrylic polymer (A), more preferably It is 0-10 mass %, More preferably, it is 0-5 mass %.

The weight average molecular weight (Mw) of the acrylic polymer (A) is preferably 300,000 to 1.5 million, more preferably 400,000 to 1.1 million, and still more preferably 450,000 to 900,000. By setting Mw to the above upper limit or less, the compatibility of the acrylic polymer (A) and the acrylic polymer (B) becomes good. In addition, by setting Mw in the above range, the retention performance of the adhesive sheet can be easily improved.

The content of the acrylic polymer (A) in the composition for the intermediate layer is preferably 40 to 95% by mass, and more preferably 45 to 90% by mass relative to the total amount (100% by mass) of the composition for the intermediate layer.

In addition, when the composition for an intermediate layer is diluted with a diluent such as an organic solvent as described later, the total amount of the composition for an intermediate layer means the total solid content excluding the diluent. The composition for the adhesive agent layer mentioned later is also the same.

(3.3.2 Acrylic polymer (B)) The acrylic polymer (B) is an acrylic polymer having energy ray curability by introducing an energy ray polymerizable group. The weight average molecular weight (Mw) of the acrylic polymer (B) is 50,000 to 250,000. In this embodiment, by using the component (B) in the intermediate layer, the convex electrode can be fully buried when the back surface of the semiconductor wafer is polished before energy ray curing is performed, and the convex electrode can be fully buried by performing energy ray after polishing. Curing can prevent the cohesive destruction of the intermediate layer and is easy to peel off from the semiconductor wafer.

The weight average molecular weight (Mw) of the acrylic polymer (B) is preferably 60,000 to 220,000, more preferably 70,000 to 200,000, and still more preferably 85,000 to 150,000.

The acrylic polymer (B) is an acrylic polymer into which an energy ray polymerizable group is introduced and has a structural unit derived from (meth)acrylate. The energy ray polymerizable group contained in the acrylic polymer (B) is preferably introduced into the side chain of the acrylic polymer. The energy ray polymerizable group may be a group containing an energy ray polymerizable carbon-carbon double bond, and examples thereof include (meth)acryloyl groups, vinyl groups, and the like. Among them, (meth)acryloyl groups are preferred.

The acrylic polymer (B) is preferably a reaction product obtained by reacting a polymerizable compound (Xb) having an energy ray polymerizable group with an acrylic copolymer (B0), the acrylic copolymer (B0) having The structural unit derived from the alkyl (meth)acrylate (b1) and the structural unit derived from the functional group-containing monomer (b2).

As the alkyl (meth)acrylate (b1), an alkyl (meth)acrylate having an alkyl group with 1 to 18 carbon atoms can be used. As a specific example thereof, the component (a1) is exemplified Compound. Among them, the alkyl (meth)acrylate (b1) is preferably an alkyl (meth)acrylate having 4 to 8 carbon atoms in the alkyl group. Specifically, n-butyl (meth)acrylate is preferable. Moreover, these alkyl (meth)acrylates may be used individually by 1 type, and may be used in combination of 2 or more types.

The content of the structural unit derived from the alkyl (meth)acrylate (b1) in the acrylic copolymer (B0) is preferably 50 to 95 relative to all the structural units (100% by mass) of the acrylic copolymer (B0) The mass% is more preferably 60 to 85% by mass, and still more preferably 65 to 80% by mass. If the content is 50% by mass or more, the shape of the formed intermediate layer can be sufficiently maintained. Moreover, if it is 95 mass% or less, it can ensure that the structural unit derived from (b2) component which is a reaction point with a polymerizable compound (Xb) is constant.

Examples of the functional group-containing monomer (b2) include monomers having the functional groups exemplified in the above-mentioned functional group-containing monomer (a2), and are preferably selected from hydroxyl group-containing monomers, carboxyl group-containing monomers, and epoxy group-containing monomers More than one kind. As specific compounds of these functional group-containing monomers, the same compounds as those exemplified by the component (a2) can be exemplified.

In addition, as the functional group-containing monomer (b2), a hydroxyl-containing monomer is preferred, and among these, various hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate are more preferred. By using a hydroxyalkyl (meth)acrylate, the polymerizable compound (Xb) can be relatively easily reacted with the acrylic copolymer (B0).

In addition, the functional groups in the functional group-containing monomer (a2) used in the acrylic polymer (A) and the functional group-containing monomer (b2) used in the acrylic polymer (B) may be the same or each other Different, but preferably different. That is, for example, if the functional group-containing monomer (a2) is a carboxyl group-containing monomer, it is preferable that the functional group-containing monomer (b2) is a hydroxyl group-containing monomer. In this way, when the functional groups are different from each other, for example, the acrylic polymer (B) can be preferentially crosslinked by the crosslinking agent described later, and the retention performance of the pressure-sensitive adhesive sheet can be easily improved.

The content of the structural unit derived from the functional group-containing monomer (b2) in the acrylic copolymer (B0) is preferably 10 to 45% by mass relative to all the structural units (100% by mass) of the acrylic copolymer (B0). Preferably it is 15-40 mass %, More preferably, it is 20-35% by mass. If it is 10% by mass or more, many reaction points with the polymerizable compound (Xb) can be secured, and the energy ray polymerizable group can be easily introduced into the side chain. In addition, if it is 45% by mass or less, the shape of the formed intermediate layer can be sufficiently maintained.

The acrylic copolymer (B0) may be a copolymer of (meth)acrylic acid alkyl ester (b1) and a functional group-containing monomer (b2), but it may also be (b1) component, (b2) component, and other than these ( Copolymers of monomers (b3) other than components b1) and (b2).

Examples of other monomers (b3) include the monomers exemplified by the above-mentioned monomer (a3).

The content of structural units derived from other monomers (b3) in the acrylic copolymer (B0) relative to all structural units (100% by mass) of the acrylic copolymer (B0) is preferably 0-30% by mass, more preferably It is 0-10 mass %, More preferably, it is 0-5 mass %.

The polymerizable compound (Xb) has an energy-ray polymerizable group and a substituent capable of reacting with the functional group in the structural unit derived from the component (b2) in the acrylic copolymer (B0) (hereinafter sometimes only referred to as " Reactive substituents").

As the energy ray polymerizable group, as described above, a (meth)acryloyl group, a vinyl group, and the like can be mentioned, and a (meth)acryloyl group is preferred. In addition, the polymerizable compound (Xb) is preferably a compound having 1 to 5 energy ray polymerizable groups in one molecule.

The reactive substituent in the polymerizable compound (Xb) can be appropriately changed according to the functional group of the functional group-containing monomer (b2). Examples include isocyanate groups, carboxyl groups, and epoxy groups. From the point of view, an isocyanate group is preferred. When the polymerizable compound (Xb) has an isocyanate group, for example, when the functional group of the functional group-containing monomer (b2) is a hydroxyl group, it can easily react with the acrylic copolymer (B0).

As a specific polymerizable compound (Xb), for example, (meth)acryloyloxyethyl isocyanate, m-isopropenyl-α,α-dimethylbenzyl isocyanate, (meth)acryloyl isocyanate , Allyl isocyanate, glycidyl (meth)acrylate, (meth)acrylic acid, etc. These polymerizable compounds (Xb) can be used alone or in combination of two or more kinds.

Among them, (meth)acryloxyethyl isocyanate is preferred from the viewpoint of a compound having an isocyanate group suitable for use as the above-mentioned reactive substituent and having an appropriate distance between the main chain and the energy ray polymerizable group.

The polymerizable compound (Xb) preferably reacts with 40 to 98 equivalents of functional groups in the total amount of functional groups (100 equivalents) from the functional group-containing monomer (b2) in the acrylic polymer (B), more preferably 60 to 90 equivalents The functional group reacts, and it is more preferable to react with 70 to 85 equivalents of the functional group.

In the composition for an intermediate layer, the content of the acrylic polymer (B) is preferably 5 to 60 parts by mass, and more preferably 10 to 50 parts by mass relative to 100 parts by mass of the acrylic polymer (A). By setting the content of the (B) component to a relatively small amount in this way, the intermediate layer can easily follow the unevenness of the semiconductor wafer.

(3.3.3 Crosslinking agent) The composition for an intermediate layer preferably further contains a crosslinking agent. Examples of the crosslinking agent include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, aziridine-based crosslinking agents, and metal chelate-based crosslinking agents. Among them, isocyanate-based crosslinking agents are preferred. If an isocyanate-based crosslinking agent is used, for example, when the (B) component has a hydroxyl group, the crosslinking agent preferentially crosslinks the acrylic polymer (B).

The composition for an intermediate layer is cross-linked with a cross-linking agent by heating after application, for example. Since the intermediate layer is cross-linked with an acrylic polymer, particularly a low-molecular-weight acrylic polymer (B), etc., a coating film can be appropriately formed, and it is easy to function as an intermediate layer.

The content of the crosslinking agent is preferably 0.1 to 10 parts by mass relative to 100 parts by mass of the acrylic polymer (A), more preferably 0.5 to 7 parts by mass, and still more preferably 1 to 5 parts by mass.

Examples of the isocyanate-based crosslinking agent include polyisocyanate compounds. Specific examples of polyisocyanate compounds include aromatic polyisocyanates such as toluene diisocyanate, diphenylmethane diisocyanate, and xylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, Alicyclic polyisocyanates such as hydrogenated diphenylmethane diisocyanate, etc. In addition, their biuret bodies, isocyanurate bodies, and low-molecular active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil can also be cited. Adducts of reaction products, etc.

These isocyanate-based crosslinking agents may be used alone or in combination of two or more. In addition, among them, polyol (for example, trimethylolpropane, etc.) adducts of aromatic polyisocyanates such as toluene diisocyanate are preferred.

In addition, examples of epoxy crosslinking agents include 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidol Methyl-m-xylylenediamine, ethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trihydroxypropane diglycidyl ether, diglycidylaniline, diglycidylamine, etc. These epoxy-based crosslinking agents may be used singly or in combination of two or more.

As the metal chelate crosslinking agent, for example, acetone, ethyl acetate, tris(2,4-pentanedione), etc. and aluminum, iron, copper, zinc, tin, titanium, nickel, Compounds formed by coordination of multivalent metals such as antimony, magnesium, vanadium, chromium, and zirconium. These metal chelate crosslinking agents may be used alone or in combination of two or more.

As the aziridine-based crosslinking agent, for example, diphenylmethane-4,4'-bis(1-aziridine methamide), trimethylolpropane tris-β-aziridinyl propionate , Tetramethylolmethane tris-β-aziridinyl propionate, toluene-2,4-bis(1-aziridine methamide), triethylene melamine, bis-m-xylylenedimethan-1-( 2-methylaziridine), tri-1-(2-methylaziridine) phosphine, trimethylolpropane tri-β-(2-methylaziridine) propionate, hexa[1- (2-Methyl)-aziridinyl] triphosphatriazine (hexa[1-(2-methyl)-aziridnyl]triphosphatriazine) and the like.

(3.3.4 Photopolymerization initiator) The composition for an intermediate layer preferably further contains a photopolymerization initiator. By including the photopolymerization initiator in the composition for the intermediate layer, the composition for the intermediate layer is easily cured by energy rays such as ultraviolet rays.

Examples of the photopolymerization initiator include acetophenone, 2,2-diethoxybenzophenone, 4-methylbenzophenone, 2,4,6-trimethylbenzophenone, Michele ketone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyl diphenyl sulfide, tetramethylthiuram monosulfide, Benzyl dimethyl ketal, dibenzyl, diacetyl, 1-chloroanthraquinone, 2-chloroanthraquinone, 2-ethylanthraquinone, 2,2-dimethoxy-1,2- Diphenylethane-1-one, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinylacetone-1,2-benzyl 2-Dimethylamino-1-(4-morpholinylphenyl)-butanone-1,2-hydroxy-2-methyl-1-phenyl-propan-1-one, diethylthio Low molecular weight polymerization initiators such as xanthone, isopropyl thioxanthone, 2,4,6-trimethylbenzyl diphenyl-phosphine oxide, oligo {2-hydroxy-2-methyl-1-[ 4-(1-methylvinyl)phenyl]acetone} and other oligomerized polymerization initiators. These photopolymerization initiators may be used alone, or two or more of them may be used in combination. Furthermore, among them, 1-hydroxycyclohexyl phenyl ketone is preferable.

In order to fully cure even when the content of the acrylic polymer (B) is small, the content of the photopolymerization initiator is preferably 1-10 parts by mass, more preferably 2 parts by mass relative to 100 parts by mass of the acrylic polymer (A) ~8 parts by mass.

The composition for an intermediate layer may contain other additives within a range that does not impair the effects of the present invention. Examples of other additives include antioxidants, softeners (plasticizers), fillers, rust inhibitors, pigments, dyes, tackifiers, and the like. When these additives are contained, the content of each additive is preferably 0.01 to 6 parts by mass, and more preferably 0.01 to 2 parts by mass relative to 100 parts by mass of the acrylic polymer (A).

In addition, for the storage modulus and loss tangent of the intermediate layer, for example, when the acrylic polymer (B) is used, the type and amount of monomers constituting the acrylic polymer (B), the acrylic polymer (B) The amount of energy ray polymerizable groups introduced in) is adjusted. For example, when the amount of energy ray polymerizable groups is increased, the storage modulus tends to increase. In addition, the amount of the crosslinking agent blended in the intermediate layer, the amount of the photopolymerization initiator, and the like can also be appropriately adjusted.

(4. Adhesive layer) The adhesive layer is attached to the circuit surface of the semiconductor wafer, which protects the circuit surface and supports the semiconductor wafer until it is peeled from the circuit surface. In this embodiment, the adhesive layer and the intermediate layer sufficiently follow the unevenness formed on the surface of the semiconductor wafer, and the unevenness can be embedded in the protective sheet for semiconductor processing. As a result, even when the semiconductor wafer is polished to be very thin and a force is applied to the convex electrode, the protective sheet for semiconductor processing can sufficiently protect the convex electrode and the like. In addition, even if the semiconductor wafers are singulated, the semiconductor wafers can be prevented from contacting each other. In addition, the adhesive layer may be composed of one layer (single layer), or may be composed of multiple layers of two or more layers.

The thickness of the adhesive layer is not particularly limited as long as it can sufficiently support the semiconductor wafer. In this embodiment, the thickness of the adhesive layer is preferably 5 μm or more and 500 μm or less, and more preferably 8 μm or more and 100 μm or less. In addition, the thickness of the adhesive layer means the thickness of the entire adhesive layer. For example, the thickness of an adhesive layer composed of multiple layers means the total thickness of all layers constituting the adhesive layer.

In this embodiment, the adhesive layer has the following physical properties.

(4.1 Storage modulus A of the adhesive layer) As mentioned above, the storage modulus (G') of the adhesive layer at 50°C is represented by the storage modulus A. The storage modulus A is not limited as long as it satisfies the above-mentioned range of "A/I". In this embodiment, the storage modulus A is preferably 0.03 MPa or more and 0.15 MPa or less. In addition, the storage modulus A is more preferably 0.04 MPa or more, and even more preferably 0.12 MPa or more. In addition, the storage modulus A is more preferably 0.05 MPa or less, and even more preferably 0.10 MPa or less. In addition, in this embodiment, when the adhesive layer has energy ray curability, the storage modulus A is the storage modulus before energy ray curing.

The storage modulus (storage modulus A) of the adhesive layer at 50°C may be measured by a known method. For example, the adhesive layer can be made into a sample of a specified size, and the sample can be deformed at a frequency of 1 Hz within a specified temperature range through a dynamic viscoelasticity measuring device, and the elastic modulus can be measured, which can be calculated from the measured elastic modulus Out of storage modulus A.

(4.2 Composition for adhesive layer) As long as the adhesive layer has the above-mentioned physical properties, the composition of the adhesive layer is not particularly limited. In the present embodiment, the adhesive layer is preferably composed of a composition having a resin (composition for an adhesive layer). Specifically, it is preferable that the composition for an adhesive layer is energy ray curable. By making the composition for the adhesive layer curable with energy ray, it has a high adhesive force that can sufficiently maintain the semiconductor wafer before the energy ray is irradiated, and after the energy ray is irradiated, the adhesive layer is cured and the adhesive force decreases due to curing. , Even when the semiconductor wafer as the adherend is singulated, it is easy to peel off from the singulated semiconductor wafer.

The composition for the adhesive layer forming the adhesive layer contains, for example, acrylic polymer, polyurethane, rubber polymer, polyolefin, silicone, etc., as an adhesive that can make the adhesive layer exhibit adhesiveness Ingredients (adhesive resin). Among them, acrylic polymers are preferred.

The composition for the adhesive layer forming the adhesive layer may have energy ray curability by blending an energy ray curable compound different from the adhesive resin, but it is preferable that the adhesive resin itself has energy ray curability. When the adhesive resin itself has energy ray curability, an energy ray polymerizable group is introduced into the adhesive resin, and the energy ray polymer group is preferably introduced into the main chain or side chain of the adhesive resin.

In addition, when an energy ray curable compound other than an adhesive resin is blended, as the energy ray curable compound, a monomer or oligomer having an energy ray polymerizable group can be used. The oligomer is an oligomer having a weight average molecular weight (Mw) of less than 10,000, and examples include urethane (meth)acrylate. In addition, even when the adhesive resin itself has energy ray curability, in addition to the adhesive resin, an energy ray curable compound may be blended in the adhesive layer composition.

Hereinafter, the case where the energy ray-curable adhesive resin contained in the adhesive layer composition is an acrylic polymer (hereinafter also referred to as "acrylic polymer (C)") will be described in more detail.

(4.2.1 Acrylic polymer (C)) The acrylic polymer (C) is an acrylic polymer into which an energy ray polymerizable group is introduced and has a structural unit derived from (meth)acrylate. The energy ray polymerizable group is preferably introduced into the side chain of the acrylic polymer.

The acrylic polymer (C) is preferably a reaction product obtained by reacting a polymerizable compound (Xc) having an energy ray polymerizable group with an acrylic copolymer (C0), the acrylic copolymer (C0) having a polymer derived from The structural unit of the alkyl (meth)acrylate (c1) and the structural unit derived from the functional group-containing monomer (c2).

As the alkyl (meth)acrylate (c1), an alkyl (meth)acrylate having an alkyl group with 1 to 18 carbon atoms can be used. As a specific example thereof, the component (a1) is exemplified Alkyl (meth)acrylate having 1 to 18 carbon atoms in the alkyl group. Among them, the alkyl (meth)acrylate (c1) is preferably an alkyl (meth)acrylate having 4 to 8 carbon atoms in the alkyl group. Specifically, 2-ethylhexyl (meth)acrylate and n-butyl (meth)acrylate are preferable, and n-butyl (meth)acrylate is more preferable. Moreover, these alkyl (meth)acrylates may be used individually by 1 type, and may be used in combination of 2 or more types.

From the perspective of improving the adhesive force of the formed adhesive layer, relative to all the structural units (100% by mass) of the acrylic copolymer (C0), the acrylic copolymer (C0) is derived from (meth)acrylic acid alkane The content of the structural unit of the base ester (c1) is preferably 50 to 99% by mass, more preferably 60 to 97% by mass, and still more preferably 70 to 96% by mass.

For example, in addition to the aforementioned 2-ethylhexyl (meth)acrylate and n-butyl (meth)acrylate, the alkyl (meth)acrylate (c1) may also contain ethyl (meth)acrylate, Methyl (meth)acrylate. By containing these monomers, it is easy to adjust the adhesive performance of the adhesive layer to the desired adhesive performance.

Examples of the functional group-containing monomer (c2) include monomers having a functional group exemplified by the above-mentioned functional group-containing monomer (a2). Specifically, it is preferably selected from hydroxyl group-containing monomers, carboxyl group-containing monomers, and epoxy-containing monomers. One or more of base monomers. As specific compounds of these functional group-containing monomers, the same compounds as those exemplified by the component (a2) can be exemplified.

As the functional group-containing monomer (c2), among the above-mentioned monomers, hydroxyl-containing monomers are more preferred, among them, hydroxyalkyl (meth)acrylate is more preferred, 2-hydroxyethyl (meth)acrylate, ( 4-hydroxybutyl meth)acrylate, 4-hydroxybutyl (meth)acrylate is particularly preferred.

By using hydroxyalkyl (meth)acrylate as the component (c2), the polymerizable compound (Xc) can be relatively easily reacted with the acrylic copolymer (C0). In addition, when 4-hydroxybutyl (meth)acrylate is used, the tensile strength of the intermediate layer is increased, and it is easy to prevent the occurrence of glue residue.

Relative to all the structural units (100% by mass) of the acrylic copolymer (C0), the content of the structural units derived from the functional group-containing monomer (c2) in the acrylic copolymer (C0) is preferably 1-40% by mass, and more It is preferably 2 to 35% by mass, and more preferably 3 to 30% by mass.

If the content is 1% by mass or more, it is possible to ensure a constant amount of the functional group as a reaction point with the polymerizable compound (Xc). Therefore, the adhesive layer can be appropriately cured by the energy ray irradiation, and therefore the adhesive force after the energy ray irradiation can be reduced. In addition, it is easy to increase the interlayer strength between the adhesive layer and the intermediate layer after the energy ray is irradiated. In addition, when the content is 40% by mass or less, a sufficient pot life can be secured when the solution of the adhesive layer composition is applied to form the adhesive layer.

The acrylic copolymer (C0) may be a copolymer of (meth)acrylic acid alkyl ester (c1) and a functional group-containing monomer (c2), but it may also be (c1) component, (c2) component, and other than these ( c1) Copolymers of monomers (c3) other than the components (c2).

As other monomers (c3), the monomers exemplified by the above-mentioned monomer (a3) can be cited.

The content of the structural units derived from other monomers (c3) in the acrylic copolymer (C0) relative to all the structural units (100% by mass) of the acrylic copolymer (C0) is preferably 0-30% by mass, more preferably It is 0-10 mass %, More preferably, it is 0-5 mass %.

Similar to the above-mentioned polymerizable compound (Xb), the polymerizable compound (Xc) has an energy-ray polymerizable group and is capable of reacting with the functional group in the structural unit derived from the component (c2) in the acrylic copolymer (C0) The compound of the substituent (reactive substituent) is preferably a compound having 1 to 5 energy ray polymerizable groups in one molecule.

Specific examples of the reactive substituent and the energy ray polymerizable group are the same as those of the polymerizable compound (Xb). Therefore, the reactive substituent is preferably an isocyanate group, and the energy ray polymerizable group is preferably a (meth)acryloyl group.

Moreover, as a specific polymerizable compound (Xc), the same compound as the compound exemplified by the above-mentioned polymerizable compound (Xb) can be mentioned, and (meth)acryloxyethyl isocyanate is preferable. In addition, the polymerizable compound (Xc) can be used singly or in combination of two or more kinds.

The polymerizable compound (Xc) preferably reacts with 30 to 98 equivalents of the functional group in the total amount (100 equivalents) of the functional group-containing monomer (c2) in the acrylic polymer (C0), more preferably 40 to 95 equivalents Functional group reaction.

The weight average molecular weight (Mw) of the acrylic polymer (C) is preferably 100,000 to 1.5 million, more preferably 250,000 to 1 million, and still more preferably 350,000 to 800,000. By having such Mw, it is possible to impart appropriate adhesiveness to the adhesive layer.

Even when the adhesive resin has energy ray curability, it is preferable to include an energy ray curable compound other than the adhesive resin in the adhesive layer composition. As such an energy ray curable compound, a monomer or oligomer which has an unsaturated group in the molecule and can be polymerized and cured by irradiation with energy rays is preferable.

Specifically, for example, trimethylolpropane tri(meth)acrylate, pentaerythritol (meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1, Poly(meth)acrylate monomers such as 4-butanediol di(meth)acrylate, 1,6-hexanediol (meth)acrylate, urethane (meth)acrylate, polyester ( Oligomers such as meth)acrylate, polyether (meth)acrylate, and epoxy (meth)acrylate.

Among them, urethane (meth)acrylate oligomers are preferred from the viewpoint of high molecular weight and difficulty in lowering the elastic modulus of the adhesive layer.

(4.2.2 Crosslinking agent) The composition for an adhesive layer preferably further contains a crosslinking agent. The composition for an adhesive layer is cross-linked with a cross-linking agent by heating after application, for example. In the adhesive layer, the acrylic polymer (C) is cross-linked by a cross-linking agent, and thereby a coating film can be appropriately formed, and the function as an adhesive layer can be easily exhibited.

Examples of the crosslinking agent include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, aziridine-based crosslinking agents, and chelate-based crosslinking agents. Among them, isocyanate-based crosslinking agents are preferred. The crosslinking agent may be used alone or in combination of two or more kinds. In addition, specific examples of the isocyanate-based crosslinking agent include the isocyanate-based crosslinking agents exemplified as the crosslinking agent that can be used in the composition for the intermediate layer, and the preferred isocyanate-based crosslinking agents are also the same.

The content of the crosslinking agent is preferably 0.01 to 10 parts by mass relative to 100 parts by mass of the acrylic polymer (C), more preferably 0.1 to 7 parts by mass, and even more preferably 0.3 to 4 parts by mass.

(4.2.3 Photopolymerization initiator) The composition for an adhesive layer preferably further contains a photopolymerization initiator. Examples of the photopolymerization initiator include the compounds exemplified as the photopolymerization initiator used in the composition for the intermediate layer. In addition, the photopolymerization initiator may be used alone or in combination of two or more kinds. In addition, among the above-mentioned photopolymerization initiators, 2,2-dimethoxy-1,2-diphenylethane-1-one and 1-hydroxycyclohexylphenyl ketone are preferable.

The content of the photopolymerization initiator relative to 100 parts by mass of the acrylic polymer (C) is preferably 0.5 to 15 parts by mass, more preferably 1 to 12 parts by mass, and even more preferably 4.5 to 10 parts by mass.

The composition for an adhesive layer may contain other additives in the range which does not impair the effect of this invention. Examples of other additives include thickeners, antioxidants, softeners (plasticizers), fillers, rust inhibitors, pigments, dyes, and the like. When these additives are contained, the content of each additive is preferably 0.01 to 6 parts by mass, and more preferably 0.02 to 2 parts by mass relative to 100 parts by mass of the acrylic polymer (C).

In addition, for the storage modulus and loss tangent of the adhesive layer, for example, when an acrylic polymer (C) is used, it can be determined by the type and amount of monomers constituting the acrylic polymer (C), and the acrylic polymer ( The amount of energy ray polymerizable groups introduced in C) is adjusted. For example, when the amount of energy ray polymerizable groups is increased, the elastic modulus tends to increase. In addition, it can also be adjusted appropriately by the amount of the crosslinking agent blended in the adhesive layer, the amount of the photopolymerization initiator, and the like.

(5. Buffer layer) As shown in FIG. 1B, the buffer layer is formed on the main surface of the base material on the opposite side to the main surface on which the adhesive layer is formed. The buffer layer 40 is a layer softer than the base material, which relieves the stress during the grinding of the back surface of the semiconductor wafer and prevents cracks and defects of the semiconductor wafer. In addition, when the back surface is polished, the semiconductor wafer with the protective sheet for semiconductor processing is placed on a vacuum table with the protective sheet for semiconductor processing interposed, but it has a buffer layer as the protective sheet for semiconductor processing. The structural layer is therefore easy to be properly maintained on the vacuum table.

The thickness of the buffer layer is preferably 1 to 100 μm, more preferably 5 to 80 μm, and still more preferably 10 to 60 μm. By setting the thickness of the buffer layer within the above-mentioned range, the buffer layer can appropriately alleviate the stress when polishing the back surface.

The buffer layer may be a layer formed of a composition for a buffer layer containing an energy ray polymerizable compound, or may be a polypropylene film, an ethylene-vinyl acetate copolymer film, an ionomer resin film, or ethylene-(meth)acrylic acid Copolymer film, ethylene-(meth)acrylate copolymer film, LDPE film, LLDPE film and other films.

In addition, a substrate having a buffer layer can be obtained by laminating a buffer layer on one side or both sides of the substrate.

(5.1 Composition for buffer layer) The composition for a buffer layer containing an energy ray polymerizable compound can be cured by irradiating energy rays.

In addition, more specifically, the composition for a buffer layer containing an energy ray polymerizable compound preferably contains a urethane (meth)acrylate (d1) and an alicyclic group having 6 to 20 ring atoms or Heterocyclic polymerizable compound (d3). In addition to the aforementioned components (d1) and (d3), the composition for a buffer layer may contain a polyfunctional polymerizable compound (d2) and/or a polymerizable compound (d4) having a functional group. In addition to the above-mentioned components, the composition for a buffer layer may also contain a photopolymerization initiator. Furthermore, the composition for a buffer layer may contain other additives or resin components in the range which does not impair the effect of this invention.

Hereinafter, each component contained in the composition for a buffer layer containing an energy-ray polymerizable compound is demonstrated in detail.

(5.1.1 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 polymerizing and curing by irradiation with energy rays. Urethane (meth)acrylate (d1) is an oligomer or polymer.

The weight average molecular weight (Mw) of the component (d1) is preferably 1,000 to 100,000, more preferably 2,000 to 60,000, and still more preferably 3,000 to 20,000. In addition, the number of (meth)acrylic groups in the component (d1) (hereinafter also referred to as "the number of functional groups") may be monofunctional, difunctional, or trifunctional or higher, but monofunctionality is preferred Or dual functionality.

The component (d1) can be obtained by reacting a (meth)acrylate having a hydroxyl group with a terminal isocyanate urethane prepolymer. The terminal isocyanate urethane prepolymer is obtained by reacting a polyol compound with a polyisocyanate compound Obtained by reaction. In addition, the component (d1) may be used alone or in combination of two or more kinds.

The polyol compound as a raw material of the component (d1) is not particularly limited as long as it is a compound having two or more hydroxyl groups. It can be any of bifunctional diols, trifunctional triols, and tetrafunctional or higher polyols, but bifunctional diols are preferred, and polyester diols or polycarbonate diols are more preferred. alcohol.

Examples of polyvalent isocyanate compounds include aliphatic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate, isophorone diisocyanate, norbornane Alicyclic diisocyanates such as diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, ω,ω'-diisocyanate dimethylcyclohexane and other alicyclic diisocyanates , 4,4'-diphenylmethane diisocyanate, toluene diisocyanate, xylene diisocyanate, dimethyl biphenyl diisocyanate, tetramethylene xylene diisocyanate, naphthalene-1,5-diisocyanate and other aromatics Diisocyanates, etc.

Among them, isophorone diisocyanate, hexamethylene diisocyanate, and xylene diisocyanate are preferred.

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

Specific examples of (meth)acrylates having a hydroxyl group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 4-hydroxycyclohexyl (meth)acrylate, 5-hydroxycyclooctyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, pentaerythritol tri(meth)acrylate , Polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate and other (meth) hydroxyalkyl acrylates, N-methylol (meth) acrylamide and other hydroxyl-containing ( Meth)acrylamide, a reaction product obtained by reacting (meth)acrylic acid with vinyl alcohol, vinylphenol, and diglycidyl ester of bisphenol A, etc.

Among them, hydroxyalkyl (meth)acrylate is preferred, and 2-hydroxyethyl (meth)acrylate is more preferred.

As the conditions for reacting the terminal isocyanate urethane prepolymer and the (meth)acrylate having a hydroxyl group, it is preferable to react at 60 to 100°C for 1 to 4 hours in the presence of a solvent and a catalyst added as needed condition.

The content of the component (d1) in the composition for the buffer layer is preferably 10 to 70% by mass, more preferably 20 to 60% by mass, and still more preferably 25% to the total amount of the composition for the buffer layer (100% by mass). 55 mass%.

(5.1.2 Multifunctional polymerizable compound (d2)) The polyfunctional polymerizable compound refers to a compound having two or more photopolymerizable unsaturated groups. The photopolymerizable unsaturated group is a functional group containing a carbon-carbon double bond, and examples thereof include (meth)acrylic groups, vinyl groups, allyl groups, and vinylbenzyl groups. The photopolymerizable unsaturated group may be used in combination of two or more types. By reacting the photopolymerizable unsaturated group in the multifunctional polymerizable compound with the (meth)acrylic acid group in the component (d1) or the photopolymerizable unsaturated group in the component (d2) with each other, A three-dimensional network structure (crosslinked structure) is formed. When a multifunctional polymerizable compound is used, the cross-linked structure formed by irradiation of energy rays increases compared to the case of using a compound containing only one photopolymerizable unsaturated group, so the buffer layer exhibits unique viscoelasticity , It is easy to relieve the stress when polishing the back surface.

In addition, there is a overlap between the definition of the component (d2) and the definition of the component (d3) or the component (d4) described later, but the overlap is included in the component (d2). For example, a compound having an alicyclic or heterocyclic group with 6 to 20 ring atoms and two or more (meth)acrylic groups is included in the two definitions of component (d2) and component (d3) However, in the present invention, the compound is considered to be included in the component (d2). In addition, compounds containing functional groups such as hydroxyl, epoxy, amino, and amino groups and having two or more (meth)acrylic groups are included in the two definitions of component (d2) and component (d4), but In the present invention, the compound is considered to be included in the component (d2).

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

In addition, 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.

As a specific component (d2), for example, diethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, neopentyl diacrylate, Alcohol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate Base) acrylate, dipentaerythritol hexa(meth)acrylate, divinylbenzene, vinyl (meth)acrylate, divinyl adipate, N,N'-methylenebis(meth)acrylic acid Amine etc. Among them, dipentaerythritol hexa(meth)acrylate is preferred. Moreover, the component (d2) can be used individually or in combination of 2 or more types.

The content of the component (d2) in the composition for the buffer layer is preferably 0-40% by mass, more preferably 3-20% by mass, and still more preferably 5~ 15% by mass.

(5.1.3 Polymeric compounds having an alicyclic group or heterocyclic group with 6-20 ring atoms (d3)) Component (d3) is a polymerizable compound having an alicyclic or heterocyclic group having 6 to 20 ring atoms, and is preferably a compound having at least one (meth)acryloyl group, more preferably having one (former Group) acryloyl compound. By using the component (d3), the film-forming properties of the obtained composition for a buffer layer can be improved.

In addition, there is a overlap between the definition of the component (d3) and the definition of the component (d4) described later, but the overlap is included in the component (d4). For example, a compound having at least one (meth)acryloyl group, an alicyclic or heterocyclic group with 6 to 20 ring atoms, and a functional group such as a hydroxyl group, an epoxy group, an amino group, and an amino group are included in the component In the two definitions of (d3) and component (d4), the compound is considered to be included in component (d4) in the present invention.

Specific components (d3) include, for example, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentyl (meth)acrylate, and dicyclopentenyloxy (meth)acrylate ( (Meth) acrylate, cyclohexyl (meth)acrylate, adamantyl (meth)acrylate and other alicyclic group-containing (meth)acrylates, tetrahydrofurfuryl (meth)acrylate, (meth) ) Heterocyclic group-containing (meth)acrylates such as morpholine (meth)acrylate, etc. In addition, the component (d3) may be used alone or in combination of two or more kinds.

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

The content of the component (d3) in the composition for the buffer layer is preferably from 10 to 80% by mass, more preferably from 20 to 70% by mass, and even more preferably from 25 to 25, relative to the total amount (100% by mass) of the composition for the buffer layer. 60% by mass.

(5.1.4 Polymerizable compounds with functional groups (d4)) Component (d4) is a polymerizable compound containing functional groups such as a hydroxyl group, an epoxy group, an amide group, an amino group, etc., and is preferably a compound having at least one (meth)acrylic group, and more preferably one (meth)acrylic group Acetyl compounds.

The compatibility of the component (d4) and the component (d1) is good, and it is easy to adjust the viscosity of the composition for a buffer layer to an appropriate range. Moreover, even if the buffer layer is made thinner, the buffer performance is good.

As the component (d4), for example, a hydroxyl group-containing (meth)acrylate, an epoxy group-containing compound, an amide group-containing compound, an amino group-containing (meth)acrylate, and the like can be cited. Among them, (meth)acrylates containing hydroxyl groups are preferred.

Examples of hydroxyl-containing (meth)acrylates include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, (meth) Base) 2-hydroxybutyl acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, phenylhydroxypropyl (meth)acrylate, 2-hydroxy-3-phenoxy Propyl acrylate and the like. Among them, hydroxyl group-containing (meth)acrylates having an aromatic ring such as phenylhydroxypropyl (meth)acrylate are more preferred. In addition, the component (d4) may be used alone or in combination of two or more kinds.

In order to improve the film-forming properties of the composition for the buffer layer, the content of the component (d4) in the composition for the buffer layer is preferably 0-40% by mass, more preferably, relative to the total amount (100% by mass) of the composition for the buffer layer It is 7 to 35% by mass, more preferably 10 to 30% by mass.

(5.1.5 Polymerizable compounds (d5) other than components (d1) ~ (d4)) Within a range that does not impair the effects of the present invention, the composition for a buffer layer may contain other polymerizable compounds (d5) in addition to the above-mentioned components (d1) to (d4).

As the component (d5), for example, alkyl (meth)acrylate having an alkyl group having 1 to 20 carbon atoms, styrene, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, N- Vinyl compounds such as vinylformamide, N-vinylpyrrolidone, and N-vinylcaprolactam. Moreover, the component (d5) can be used individually or in combination of 2 or more types.

The content of the component (d5) in the composition for a buffer layer is preferably 0 to 20% by mass, more preferably 0 to 10% by mass, even more preferably 0 to 5% by mass, and particularly preferably 0 to 2% by mass.

(5.1.6 Photopolymerization initiator) From the viewpoints of shortening the polymerization time by light irradiation when forming the buffer layer and reducing the amount of light irradiation, the composition for the buffer layer preferably further contains a photopolymerization initiator.

Examples of the photopolymerization initiator include benzoin compounds, acetophenone compounds, phosphine oxide compounds, titanocene compounds, thioxanthone compounds, peroxides, and photosensitizers such as amines or quinones. More specifically For example, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propane-1-one, benzoin, benzoin methyl ether, benzoin ethyl ether , Benzoin isopropyl ether, benzyl phenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, bibenzyl, diacetyl, 8-chloroanthraquinone, bis(2,4, 6-trimethylbenzyl) phenyl phosphine oxide and the like. These photoinitiators can be used individually or in combination of 2 or more types.

The content of the photopolymerization initiator in the composition for the buffer layer is preferably 0.05 to 15 parts by mass, more preferably 0.1 to 10 parts by mass, and still more preferably 0.3 to 5 parts by mass relative to 100 parts by mass of the total amount of the energy ray polymerizable compound. Mass parts.

(5.1.7 Other additives) The composition for a buffer layer may contain other additives in the range which does not impair the effect of this invention. Examples of other additives include antistatic agents, antioxidants, softeners (plasticizers), fillers, rust inhibitors, pigments, dyes, and the like. When these additives are blended, the content of each additive in the buffer layer composition is preferably 0.01 to 6 parts by mass, and more preferably 0.1 to 3 parts by mass relative to 100 parts by mass of the total amount of the energy ray polymerizable compound.

A buffer layer formed of a composition for a buffer layer containing an energy-ray polymerizable compound is obtained by polymerizing and curing the composition for a buffer layer having the above-mentioned composition by irradiating energy rays. That is, the buffer layer is a product obtained by curing a composition for a buffer layer.

Therefore, the buffer layer preferably contains a polymerized unit derived from the component (d1) and a polymerized unit derived from the component (d3). In addition, the buffer layer may contain a polymerized unit derived from the component (d2) and/or a polymerized unit derived from the component (d4), and may also contain a polymerized unit derived from the component (d5). The content ratio of each polymer unit in the buffer layer is usually the same as the ratio (addition ratio) of each component constituting the combination for the buffer layer.

(6. Peeling sheet) A release sheet can be attached to the surface of the protective sheet for semiconductor processing. Specifically, the release sheet is attached to the surface of the adhesive layer of the protective sheet for semiconductor processing. The release sheet is attached to the surface of the adhesive layer to protect the adhesive layer during transportation and storage. The peeling sheet is attached to the protective sheet for semiconductor processing in a peelable manner, and is peeled and removed from the protective sheet for semiconductor processing before using the protective sheet for semiconductor processing (that is, before attaching the wafer).

As the release sheet, a release sheet having at least one surface subjected to a release treatment is used. Specifically, a release sheet obtained by coating a release agent on the surface of a base material for a release sheet, and the like can be cited.

The base material for the release sheet is preferably a resin film. Examples of the resin constituting the resin film include polyethylene terephthalate resin, polybutylene terephthalate resin, and polyethylene naphthalate resin. Polyolefin resins such as polyester resin films such as glycol ester resins, and polypropylene resins and polyethylene resins. Examples of release agents include silicone resins, olefin resins, isoprene resins, butadiene resins and other rubber elastomers, long-chain alkyl resins, alkyd resins, fluorine resins, etc. .

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

(7. Manufacturing method of protective sheet for semiconductor processing) Regarding the method of manufacturing the protective sheet for semiconductor processing of the present embodiment, as long as it is a method capable of forming an intermediate layer and an adhesive layer on one main surface of the substrate, and forming a buffer layer on the other main surface of the substrate, There is no particular limitation, and a known method can be used.

First, for example, a composition for an intermediate layer containing the above-mentioned components or a composition obtained by diluting the composition for an intermediate layer with a solvent or the like is prepared as a composition for forming an intermediate layer. Similarly, for example, a composition for an adhesive layer containing the above-mentioned components or a composition obtained by diluting the composition for an adhesive layer with a solvent or the like is prepared as the composition for an adhesive layer for forming an adhesive layer. Similarly, for example, a composition for a buffer layer containing the above-mentioned components or a composition obtained by diluting the composition for a buffer layer with a solvent or the like is prepared as a composition for a buffer layer for forming a buffer layer.

Examples of the solvent include organic solvents such as methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexane, n-hexane, toluene, xylene, n-propanol, and isopropanol.

Next, by known methods such as spin coating, spray coating, bar coating, knife coating, roll coating, blade coating, die coating, and gravure coating, The composition for a buffer layer is applied on the release-treated surface of the first release sheet to form a coating film, and the coating film is semi-cured to form a buffer layer film on the release sheet. The buffer layer film formed on the release sheet is attached to the base material, and the buffer layer film is completely cured, thereby forming a buffer layer.

In this embodiment, it is preferable to cure the coating film by irradiating energy rays. In addition, the curing of the coating film may be performed by a one-time curing treatment, or may be divided into multiple times.

Next, the composition for an intermediate layer is applied to the release-treated surface of the second release sheet by a known method and heated and dried to form an intermediate layer on the second release sheet. Then, the intermediate layer on the second release sheet is attached to the surface of the base material on which the buffer layer is not formed, and the second release sheet is removed.

Next, the composition for an adhesive layer is applied to the release-treated surface of the third release sheet by a known method and heated and dried to form an adhesive layer on the third release sheet. Then, by bonding the adhesive layer and the intermediate layer on the third release sheet, it is obtained that the intermediate layer and the adhesive layer are sequentially formed on one main surface of the base material, and the other main surface of the base material is formed Buffer layer protection sheet for semiconductor processing. In addition, the third release sheet may be removed when the protective sheet for semiconductor processing is used.

(8. Manufacturing method of semiconductor device) The protective sheet for semiconductor processing of the present invention is preferably used when attaching to the surface of a semiconductor wafer in DBG and performing backside polishing of the wafer. In particular, the protective sheet for semiconductor processing of the present embodiment is preferably used for LDBG, which can obtain a chip group with a small notch width when a semiconductor wafer is singulated.

As a non-limiting example of use of the protective sheet for semiconductor processing, the method of manufacturing a semiconductor device will be further specifically described below.

Specifically, the method of manufacturing a semiconductor device includes at least the following steps 1 to 4. Step 1: A step of attaching the above-mentioned protective sheet for semiconductor processing to the surface of a semiconductor wafer having unevenness; Step 2: forming a trench from the surface side of the semiconductor wafer, or forming a modified region inside the semiconductor wafer from the surface or back of the semiconductor wafer; Step 3: Grind the semiconductor wafer with the protective sheet for semiconductor processing attached on the surface and formed with the groove or modified region from the back side, and singulate into multiple wafers from the groove or modified region as the starting point A step of; Step 4: A step of peeling the protective sheet for semiconductor processing from the singulated semiconductor wafer (ie, a plurality of semiconductor wafers).

Hereinafter, each step of the manufacturing method of the above-mentioned semiconductor device will be described in detail.

(step 1) In step 1, the protective sheet for semiconductor processing of the present invention is attached to the surface of a semiconductor wafer having unevenness via an adhesive layer. This step can be performed before step 2 described later, or it can be performed after step 2. For example, when forming a modified region in a semiconductor wafer, it is preferable to perform step 1 before step 2. On the other hand, when grooves are formed on the surface of the semiconductor wafer by dicing or the like, step 1 is performed after step 2. That is, in step 1, a protective sheet for semiconductor processing is attached to the surface of a wafer having grooves formed in step 2 described later.

The semiconductor wafer used in this manufacturing method may be a silicon wafer, and may also be a wafer of gallium arsenide, silicon carbide, lithium tantalate, lithium niobate, gallium nitride, indium phosphide, etc., or a glass wafer. The thickness of the semiconductor wafer before polishing is not particularly limited, but it is usually about 500 to 1000 μm. In addition, semiconductor wafers usually have circuits formed on their surface. Circuits can be formed on the surface of the wafer by various methods including conventional methods such as etching and lift-off. In particular, in this embodiment, convex electrodes (bumps) are formed on the circuit surface of the semiconductor wafer. As a result, there are irregularities on the circuit surface of the semiconductor wafer compared to a semiconductor wafer in which the convex electrode is not formed. In addition, the height of the convex electrode is not particularly limited, but it is usually 5 to 200 μm.

(Step 2) In step 2, a trench is formed from the surface side of the semiconductor wafer, or a modified region is formed inside the semiconductor wafer from the surface or back of the semiconductor wafer.

The trench formed in this step is a trench having a depth shallower than the thickness of the semiconductor wafer. The groove can be formed by dicing using a conventionally known wafer dicing device or the like. In addition, the semiconductor wafer is divided into a plurality of semiconductor wafers along the trench in step 3 described later.

In addition, the modified region is the embrittled part of the semiconductor wafer, and is the region where the semiconductor wafer is singulated into the starting point of the semiconductor wafer. In this singulation, the semiconductor wafer is changed by polishing in the polishing step. Thin, apply the force generated by grinding, thereby destroying the semiconductor wafer, and then singulate it into a semiconductor wafer. That is, the trenches and modified regions in step 2 are formed along the dividing lines when the semiconductor wafer is divided and singulated into semiconductor wafers in the subsequent step 3.

The modified region is formed by laser irradiation focused on the inside of the semiconductor wafer, and the modified region is formed inside the semiconductor wafer. The laser irradiation may be performed from the front side of the semiconductor wafer, or may be performed from the back side. In addition, in the method of forming the modified region, when step 2 is performed after step 1 and laser irradiation is performed from the surface of the wafer, the semiconductor wafer is irradiated with the laser through the protective sheet for semiconductor processing.

The semiconductor wafer attached with the protective sheet for semiconductor processing and formed with grooves or modified regions is placed on a chuck table and adsorbed on the chuck table to be held. At this time, the surface side of the semiconductor wafer is arranged and adsorbed to the table side.

(Step 3) After step 1 and step 2, the back surface of the semiconductor wafer on the chuck table is polished, and the semiconductor wafer is singulated into a plurality of semiconductor wafers.

Here, when a trench is formed on the semiconductor wafer, back grinding is performed in such a way that the semiconductor wafer is thinned to at least the bottom of the trench. By this back grinding, the trench is formed as a cut through the wafer, and the semiconductor wafer is divided by the cut and singulated into individual semiconductor wafers.

On the other hand, when a modified region is formed, the polished surface (the back surface of the wafer) may reach the modified region by polishing, but it may not reach the modified region accurately. That is, it is sufficient to polish to a position close to the modified region in such a manner that the semiconductor wafer can be broken from the modified region as a starting point to be singulated into a semiconductor wafer. For example, the actual singulation of a semiconductor wafer can be performed by extending the pickup tape after attaching the pickup tape described later.

In addition, dry polishing can be performed after finishing the back grinding and before picking up the wafer.

The shape of the singulated semiconductor wafer may be a square, or may be formed into an elongated shape such as a rectangle. In addition, the thickness of the singulated semiconductor wafer is not particularly limited, but is preferably about 5 to 100 μm, and more preferably 10 to 45 μm. According to LDBG, which uses lasers to provide modified regions inside the wafer and singulates the wafer using stress during polishing the back of the wafer, it is easy to make the thickness of the singulated semiconductor wafer 50μm or less, more preferably Make 10~45μm. In addition, the size of the singulated semiconductor wafer is not particularly limited, but the wafer size is preferably less than 600 mm ² , more preferably less than 400 mm ² , and still more preferably less than 120 mm ² .

If the protective sheet for semiconductor processing of the present invention is used, even if it is such a thin and/or small semiconductor wafer, it can be prevented that the back surface is polished (step 3) and when the protective sheet for semiconductor processing is peeled off (step 4). Cracks are generated on the semiconductor wafer.

(Step 4) Next, the protective sheet for semiconductor processing is peeled off from the singulated semiconductor wafer (that is, a plurality of semiconductor wafers). This step is performed by the following method, for example.

First, when the adhesive layer of the protective sheet for semiconductor processing is formed of an energy ray-curable adhesive, energy ray is irradiated to cure the adhesive layer. Next, a pick-up tape is attached to the back side of the singulated semiconductor wafer, and the position and direction are aligned in a pick-up manner. At this time, the ring frame arranged on the outer peripheral side of the wafer is also attached to the pick-up tape, and the outer peripheral edge of the pick-up tape is fixed to the ring frame. The wafer and the ring frame can be attached to the pick-up tape at the same time, or they can be attached at different times. Next, the protective sheet for semiconductor processing is peeled from the plurality of semiconductor wafers held on the pickup tape.

Then, a plurality of semiconductor wafers located on the pickup tape are picked up and fixed on a substrate or the like, thereby manufacturing a semiconductor device.

In addition, the pick-up tape is not particularly limited, and is composed of, for example, an adhesive sheet including a base material and an adhesive layer provided on one surface of the base material.

As mentioned above, the protective sheet for semiconductor processing of the present invention has been described as an example in which it is applied to the method of singulating semiconductor wafers by DBG or LDBG. However, the protective sheet for semiconductor processing of the present invention is preferably applied to LDBG Among them, when the LDBG singulates a semiconductor wafer, it is possible to obtain a chip set with a small cut width and a thinner chip.

The embodiments of the present invention have been described above, but the present invention is not limited to the above-mentioned embodiments at all, and can be modified in various ways within the scope of the present invention. [Example]

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

The test method and evaluation method in this embodiment are as follows.

(The loss tangent of the middle layer and the storage modulus) The composition for the intermediate layer described later is formed by a knife coater into a polyethylene terephthalate (PET) film-based release film (product name "SP-PET381031", thickness 38μm) attached to both sides , LINTEC Corporation) and an intermediate layer with a thickness of 50μm.

A plurality of intermediate layers formed in the above-mentioned manner were prepared, the PET-based release film was peeled off, and the peeling surfaces were aligned with each other and sequentially laminated, thereby manufacturing a laminate (thickness of 1,000 μm) of the intermediate layer.

Next, the obtained laminated body of the intermediate layer was punched into a circle with a diameter of 10 mm to obtain a sample for testing viscoelasticity.

Using a viscoelasticity measuring device (product name "ARES", manufactured by TA Instruments), the above sample was deformed at a frequency of 1 Hz, and the storage modulus (G '), calculate the loss tangent (tanδ) at 50°C and the storage modulus (G') at 50°C from the measured values. Set the calculated value of the storage modulus to the storage modulus I.

(The loss tangent and storage modulus of the adhesive layer) Using the adhesive layer composition described below, a knife coater was used to form a peeling film with polyethylene terephthalate (PET) film on both sides (product name "SP-PET381031", thickness 38μm, LINTEC Corporation) and an adhesive layer with a thickness of 50 μm.

A plurality of adhesive layers formed in the above-mentioned manner were prepared, the PET-based release film was peeled off, and the peeling surfaces were aligned with each other and sequentially laminated, thereby manufacturing a laminate (thickness of 1,000 μm) of the adhesive layer.

Next, the obtained laminated body of the adhesive layer was punched into a circle with a diameter of 10 mm to obtain a sample for testing viscoelasticity.

Using a viscoelasticity measuring device (product name "ARES", manufactured by TA Instruments), the above sample was deformed at a frequency of 1 Hz, and the storage modulus of -30 to 120 °C was measured at a temperature increase rate of 10 °C/min. The measured value calculates the storage modulus (G') at 50°C. Set this value to storage modulus A.

(DBG wafer crack evaluation) After forming grooves on the surface of a silicon wafer with a diameter of 12 inches, the protective sheets for semiconductor processing manufactured in the examples and comparative examples were attached to the surface of the wafer, and the back surface was polished to singulate the wafer. Therefore, the wafer is singulated into a wafer with a thickness of 50 μm and a wafer size of 5 mm square by the first dicing method. Then, without peeling off the protective sheet for semiconductor processing, use a digital microscope (product name "VHX-1000", manufactured by KEYENCE CORPORATION) to observe the corners of the singulated wafer from the polished surface of the wafer to observe whether each wafer is present or not. For cracks, the rate of occurrence of cracks in 700 wafers was measured and evaluated according to the following evaluation criteria. A: less than 1.0%, B: 1.0~2.0%, C: greater than 2.0%

(LDBG wafer crack evaluation) Using a back grinding tape laminator (manufactured by LINTEC Corporation, device name "RAD-3510F/12"), the semiconductor processing protective sheets manufactured in the examples and comparative examples were attached to a 12-inch diameter and 775μm thick On a silicon wafer. Using a laser saw (manufactured by DISCO Corporation, device name "DFL7361"), a lattice-shaped modified area is formed on the wafer. In addition, the grid size is 5mm×5mm.

Next, using a backside polishing device (manufactured by DISCO Corporation, device name "DGP8761"), polishing (including dry polishing) is performed until the thickness is 50 μm, and the wafer is singulated into multiple wafers.

After the polishing step is irradiated with energy rays (ultraviolet rays), a dicing tape (manufactured by LINTEC Corporation, Adwill D-176) is attached to the opposite surface of the attaching surface of the semiconductor processing protective sheet, and then the semiconductor processing protective sheet is peeled off. Then, using a digital microscope (product name "VHX-1000", manufactured by KEYENCE CORPORATION), observe the singulated wafers, count the number of cracked wafers, measure the rate of crack generation in 700 wafers, and use the following evaluation criteria. Evaluation. A: less than 1.0%, B: 1.0~2.0%, C: greater than 2.0%

(Evaluation of incision adhesion) Peel off the release sheet on the protective sheet for semiconductor processing with a release sheet manufactured in the Examples and Comparative Examples, and place the protective sheet for semiconductor processing on a tape laminating machine (manufactured by LINTEC Corporation, product name "RAD-3510"), According to the following conditions, it was attached to a 12-inch silicon wafer (thickness of 760 μm) with grooves formed on the surface of the wafer by the dicing method. Roll height: 0mm, roll temperature: 23°C (room temperature), table temperature: 23°C (room temperature)

The obtained silicon wafer with a protective sheet for semiconductor processing was singulated into a wafer size of 50 μm in thickness and 5 mm square by back grinding (pre-dicing method). Mount the singulated protective sheet for semiconductor processing with wafers on a dicing tape placement machine (manufactured by LINTEC Corporation, product name "RAD-2700"), and irradiate ultraviolet rays from the tape side (conditions: 230mW/cm, 380mJ/cm) ) To cure the adhesive. Then, in the same RAD-2700 device, a pick-up tape (manufactured by LINTEC Corporation, product name "D-510T") is attached from the chip side. At this time, a jig called a ring frame used in the pick-up step is also aligned and attached to the pick-up tape. Next, in the RAD-2700 device, peel off the cured protective sheet for semiconductor processing. Using a digital microscope (product name "VHX-1000", manufactured by KEYENCE CORPORATION), observe 700 wafers after peeling off the protective sheet for semiconductor processing, and confirm whether there is any glue residue near the cuts. Mark the ones without glue residue as ○, and there will be glue residues. Denoted as ×.

(Evaluation of bump absorbency) Using a laminator (product name "RAD-3510F/12", manufactured by LINTEC Corporation), attach the following examples and comparative examples on a wafer with ball bumps (8-inch wafer, manufactured by WALTZ Corporation) The manufactured protective sheet for semiconductor processing, wherein the spherical bumps have a bump height of 80 μm, a pitch of 200 μm, and a diameter of 100 μm, and are made of Sn-3Ag-0.5Cu alloy. In addition, at the time of sticking, the temperature of the laminating table and the laminating roller of the device was set to 50°C.

After lamination, using a digital optical microscope (product name "VHX-1000", manufactured by KEYENCE CORPORATION), the diameter of the circular voids generated around the bumps was measured from the substrate side.

The smaller the diameter of the void, the higher the bump absorbency of the protective sheet for semiconductor processing. According to the following criteria, determine the pros and cons of bump absorbency. ○: The diameter of the void is less than 150 μm. ×: The diameter of the void is 150 μm or more.

(Example 1) (1) Substrate Prepare a PET film (COSMOSHINE A4300 manufactured by TOYOBO CO., LTD., thickness: 50μm, Young's modulus at 23°C: 2550MPa) with easy-adhesive layers on both sides as a substrate.

(2) Buffer layer (Synthesis of urethane acrylate oligomer) The 2-hydroxyethyl acrylate is reacted with a terminal isocyanate urethane prepolymer to obtain a urethane acrylate oligomer (UA-2) with a weight average molecular weight (Mw) of about 9000. The terminal isocyanate amino group The formate prepolymer is obtained by reacting polyester diol with isophorone diisocyanate.

(Preparation of composition for buffer layer) Blending 40 parts by mass of the above-synthesized urethane acrylate oligomer (UA-2), 20 parts by mass of isobornyl acrylate (IBXA), 20 parts by mass of tetrahydrofurfuryl acrylate (THFA), and propylene 20 parts by mass of morpholine (ACMO) and 2-hydroxy-2-methyl-1-phenyl-propane-1-one (manufactured by BASF Japan Ltd, product name "IRGACURE 1173) mixed as a photopolymerization initiator ") 2.0 parts by mass to prepare a composition for a buffer layer.

(Manufacturing of base material with buffer layer) The composition for the buffer layer was coated on the release-treated surface of the other release sheet (manufactured by LINTEC Corporation, product name "SP-PET381031") to form a coating film. Next, the coating film was irradiated with ultraviolet rays to semi-cured the coating film to form a buffer layer forming film having a thickness of 53 μm.

In addition, a conveyor-type ultraviolet irradiation device (manufactured by EYE GRAPHICS Co., Ltd., device name "US2-0801") and a high-pressure mercury lamp (manufactured by EYE GRAPHICS Co., Ltd., device name "H08-L41") are used in The above-mentioned ultraviolet irradiation was performed under irradiation conditions of a lamp height of 230 mm, an output power of 80 mW/cm, an illuminance of light with a wavelength of 365 nm of 90 mW/cm ² and an irradiation amount of 50 mJ/cm ^2.

Next, the surface of the formed buffer layer forming film is bonded to the base material, and ultraviolet rays are irradiated again from the release sheet side on the buffer layer forming film to completely cure the buffer layer forming film to form a buffer layer with a thickness of 53 μm. In addition, using the above-mentioned ultraviolet irradiation device and high-pressure mercury lamp, under the irradiation conditions of a lamp height of 220mm, a converted output power of 120mW/cm, a wavelength of 365nm light, an illuminance of 160mW/cm ² , and an irradiation amount of 650mJ/cm ² , Carry out the above-mentioned ultraviolet irradiation.

(3) Substrate A with intermediate layer 91 parts by mass of n-butyl acrylate (BA) and 9 parts by mass of acrylic acid (AA) were copolymerized to obtain a non-energy-ray curable acrylic copolymer (a) (Mw: 600,000).

Different from the acrylic copolymer (a), 62 parts by mass of n-butyl acrylate (BA), 10 parts by mass of methyl methacrylate (MMA), and 28 parts by mass of 2-hydroxyethyl acrylate (2HEA) are copolymerized to obtain Acrylic polymer, and polymerize 2-methacryloxyethyl isocyanate (MOI) with acrylic by adding 80 equivalents of hydroxyl groups in the total hydroxyl groups (100 equivalents) of acrylic polymer The substance reacted to obtain an energy ray-curable acrylic copolymer (b) (Mw: 100,000).

To 100 parts by mass of the non-energy-ray-curable acrylic copolymer (a), 13 parts by mass of the energy-ray-curable acrylic copolymer (b) were added, and an isocyanate-based crosslinking agent (TOSOH Co., Ltd.) was added as a crosslinking agent. Manufacture, product name "CORONATE L") 2.79 parts by mass, add 3.71 parts by mass of 1-hydroxycyclohexyl phenyl ketone (manufactured by BASF Corporation, Irgacure 184) as a photopolymerization initiator, and adjust the solid content concentration to 37% using toluene, Stirring was performed for 30 minutes to prepare a composition for an intermediate layer.

Next, the prepared solution of the composition for an intermediate layer was coated on a PET-based release film (manufactured by LINTEC Corporation, SP-PET381031, thickness 38 μm) and dried to form an intermediate layer with a thickness of 60 μm. It was bonded to the surface of the above-mentioned substrate with a buffer layer opposite to the surface on which the buffer layer was formed, and then an adhesive layer was repeatedly coated on a PET-based release film (manufactured by LINTEC Corporation, SP-PET381031, thickness 38μm) This operation was repeated twice with the solution of the composition to form a substrate A with an intermediate layer having a thickness of 180 μm.

(4) Adhesive layer (Preparation of composition for adhesive layer) 52 parts by mass of n-butyl acrylate (BA), 20 parts by mass of methyl methacrylate (MMA), and 28 parts by mass of 2-hydroxyethyl acrylate (2HEA) were copolymerized to obtain an acrylic polymer, which was combined with acrylic The method of adding 90 equivalents of the hydroxyl groups in the total hydroxyl groups (100 equivalents) of the polymer to react 2-methacryloyloxyethyl isocyanate (MOI) with the acrylic polymer to obtain energy-ray curable acrylic acid Class copolymer (c) (Mw: 500,000).

12 parts by mass of a polyfunctional urethane acrylate (manufactured by Mitsubishi Chemical Corporation, SHIKOH UT-4332) which is an energy ray curable compound is blended with 100 parts by mass of the energy ray curable acrylic copolymer (c) , Isocyanate-based crosslinking agent (manufactured by TOSOH CORPORATION, product name "CORONATE L") 1.1 parts by mass, and adding bis(2,4,6-trimethylbenzyl)phenyl phosphine oxide as a photopolymerization initiator (Manufactured by BASF Corporation, Irgacure TPO) 1 part by mass was diluted with methyl ethyl ketone to prepare a coating liquid of a composition for an adhesive layer having a solid content concentration of 34% by mass.

(Manufacturing of protective sheets for semiconductor processing) Coating the coating solution of the adhesive layer composition obtained above on the release treatment surface of the release sheet (manufactured by LINTEC Corporation, product name "SP-PET381031"), and heat and dry it to form an adhesive with a thickness of 10 μm on the release sheet Floor.

Then, an adhesive layer was bonded to the surface of the substrate A with an intermediate layer on which the intermediate layer was formed to produce a protective sheet for semiconductor processing. Table 1 shows the type of substrate, the composition and thickness of the intermediate layer and the adhesive layer.

(Example 2) A protective sheet for semiconductor processing was obtained in the same manner as in Example 1, except that the thickness of the intermediate layer was 120 μm. Table 1 shows the type of substrate, the composition and thickness of the intermediate layer and the adhesive layer.

(Example 3) Except that the addition amount of the acrylic copolymer (b) of the composition for the intermediate layer was changed to 34 parts by mass, the same method as in Example 1 was used to obtain a protective sheet for semiconductor processing. Table 1 shows the type of substrate, the composition and thickness of the intermediate layer and the adhesive layer.

(Example 4) Except that the addition amount of the acrylic copolymer (b) of the composition for the intermediate layer was changed to 67 parts by mass, the same method as in Example 1 was used to obtain a protective sheet for semiconductor processing. Table 1 shows the type of substrate, the composition and thickness of the intermediate layer and the adhesive layer.

(Example 5) Except that the addition amount of the acrylic copolymer (b) of the composition for the intermediate layer was changed to 100 parts by mass, the same method as in Example 1 was used to obtain a protective sheet for semiconductor processing. Table 1 shows the type of substrate, the composition and thickness of the intermediate layer and the adhesive layer.

(Example 6) The protective sheet for semiconductor processing was obtained in the same manner as in Example 1 except that the following two changes were made. Table 1 shows the type of substrate, the composition and thickness of the intermediate layer and the adhesive layer. (1) The thickness of the intermediate layer is 120 μm. (2) As a composition for the adhesive layer, 60 parts by mass of 2-ethyl hydroxy acrylate (2EHA), 15 parts by mass of ethyl acrylate (EA), 5 parts by mass of methyl methacrylate (MMA), and acrylic acid 20 parts by mass of 2-hydroxyethyl (2HEA) were copolymerized to obtain an acrylic polymer, and the 2-methyl group was added to 60 equivalents of the total hydroxyl groups (100 equivalents) of the acrylic polymer. Acrylic oxyethyl isocyanate (MOI) reacts with an acrylic polymer to obtain an energy ray-curable acrylic copolymer (d) (Mw: 500,000).

To 100 parts by mass of the energy ray-curable acrylic copolymer (d), 1.2 parts by mass of an isocyanate crosslinking agent (manufactured by TOSOH CORPORATION, product name "CORONATE L") is blended and blended as a photopolymerization initiator. 2,2-Dimethoxy-2-phenylacetophenone (manufactured by BASF Corporation, Irgacure651) 7.29 parts by mass, diluted with toluene to prepare a coating liquid of a composition for an adhesive layer with a solid content concentration of 25% by mass .

(Example 7) The protective sheet for semiconductor processing was obtained by the same method as Example 1 except changing the following points. Table 1 shows the type of substrate, the composition and thickness of the intermediate layer and the adhesive layer.

As a composition for the adhesive layer, 75 parts by mass of n-butyl acrylate (BA), 10 parts by mass of isobutyl acrylate (iBA), 5 parts by mass of methyl methacrylate (MMA), and 4-hydroxybutyl acrylate (4HBA) 10 parts by mass was copolymerized to obtain an acrylic polymer, which was added to 90 equivalents of hydroxyl groups in the total hydroxyl groups (100 equivalents) of the acrylic polymer to make 2-methacryloyloxyethoxy The base isocyanate (MOI) reacts with the acrylic polymer to obtain an energy ray-curable acrylic copolymer (e) (Mw: 500,000).

To 100 parts by mass of the energy ray-curable acrylic copolymer (e), 1.8 parts by mass of an isocyanate crosslinking agent (manufactured by TOSOH CORPORATION, product name "CORONATE L") is blended and blended as a photopolymerization initiator. 2,2-Dimethoxy-2-phenylacetophenone (manufactured by BASF Corporation, Irgacure651) 7.29 parts by mass, diluted with toluene to prepare a coating liquid of a composition for an adhesive layer with a solid content of 25% by mass .

(Example 8) A protective sheet for semiconductor processing was obtained in the same manner as in Example 2 except that the substrate with a buffer layer was changed to a PET substrate. Table 1 shows the type of substrate, the composition and thickness of the intermediate layer and the adhesive layer.

(Comparative example 1) Except that the addition amount of the acrylic copolymer (b) of the composition for the intermediate layer was changed to 134 parts by mass, the same method as in Example 1 was used to obtain a protective sheet for semiconductor processing. Table 1 shows the type of substrate, the composition and thickness of the intermediate layer and the adhesive layer.

(Comparative example 2) The protective sheet for semiconductor processing was obtained by the same method as Example 1, except using the composition for adhesive layers of Example 6 as the composition for adhesive layers. Table 1 shows the type of substrate, the composition and thickness of the intermediate layer and the adhesive layer.

(Comparative example 3) Except for using the substrate D with an intermediate layer manufactured in the following manner and using the adhesive layer composition of Example 6 as the adhesive layer composition, the semiconductor processing protection was obtained in the same manner as in Example 1. piece. Table 1 shows the type of substrate, the composition and thickness of the intermediate layer and the adhesive layer.

Substrate D with intermediate layer Blending 40 parts by mass of monofunctional urethane acrylate (solid content ratio), 45 parts by mass of isobornyl acrylate (IBXA) (solid content ratio), and 15 parts by mass of hydroxypropyl acrylate (HPA) (solid content ratio) ), tetrakis (3-mercaptobutyric acid) pentaerythritol ester (product name "KARENZ MT PE1", SHOWA DENKO KK, tetrafunctional secondary mercaptan compound, solid content concentration 100% by mass) 3.5 parts by mass (solid content ratio), 1.8 parts by mass of UV-reactive thermal crosslinking agent, and 2-hydroxy-2-methyl-1-phenyl-propan-1-one (product name "Darocur1173", manufactured by BASF Corporation, solid content) as a photopolymerization initiator The concentration is 100 parts by mass %) 1.0 parts by mass, and the prepared UV curable resin composition is coated on polyterephthalic acid in a way of a fountain die with a cured thickness of 400 μm A coating film was formed on a ethylene glycol ester (PET) film-based release film (manufactured by LINTEC Corporation, SP-PET381031, thickness 38 μm). In addition, ultraviolet rays are irradiated from the side of the coating film to form a semi-cured layer.

In addition, a conveyor belt ultraviolet irradiation device (product name "ECS-401GX", manufactured by EYE GRAPHICS Co., Ltd.) is used as the ultraviolet irradiation device, and a high-pressure mercury lamp (H04-L41, manufactured by EYE GRAPHICS Co., Ltd.) is used. As an ultraviolet source, as the irradiation conditions, the illuminance of light with a wavelength of 365nm is 112mW/cm ² and the light quantity is 177mJ/cm ² (measured by "UVPF-A1" manufactured by EYE GRAPHICS Co., Ltd.). UV exposure.

A polyethylene terephthalate (PET) film (Lumirror75U403 manufactured by TORAY INDUSTRIES, INC., thickness 75μm) is laminated on the formed semi-cured layer, and ultraviolet rays are further irradiated from the PET film side (using the above-mentioned ultraviolet irradiation device , UV source, and as an irradiation repair part, the illuminance is 271mW/cm ² , the light quantity is 1200mJ/cm ² ), it is completely cured, and an intermediate layer with a thickness of 400 μm is formed on the PET film of the base material.

[Table 1] middle layer Adhesive layer Substrate Acrylic copolymer Crosslinking agent Thickness (μm) Acrylic copolymer Urethane Acrylate Crosslinking agent Thickness (μm) (a) (b) (c) (d) (e) Example 1 100 13 2.79 180 100 12 1.1 10 PET substrate with buffer layer Example 2 100 13 2.79 120 100 12 1.1 10 Example 3 100 34 2.79 120 100 12 1.1 10 Example 4 100 67 2.79 120 100 12 1.1 10 Example 5 100 100 2.79 120 100 12 1.1 10 Example 6 100 13 2.34 120 100 1.2 10 Example 7 100 67 2.79 120 100 1.8 10 Example 8 100 13 2.79 120 100 12 1.1 10 PET substrate Comparative example 1 100 134 2.79 120 100 12 1.1 10 PET substrate with buffer layer Comparative example 2 100 13 2.79 120 100 1.2 10 Comparative example 3 Urethane acrylates 400 100 1.2 10 PET

The above-mentioned measurement and evaluation were performed on the obtained samples (Examples 1 to 8 and Comparative Examples 1 to 3). The results are shown in Table 2.

[Table 2] characteristic Evaluation 50℃ DBG evaluation results LDBG evaluation results Incision adherence Bump Intermediate layer I (MPa) Adhesive layer A (MPa) A/I ratio Intermediate layer Tanδ (-) Wafer displacement (crack) Evaluation Wafer displacement (crack) Evaluation Residue Embeddedness Example 1 0.078 0.067 0.86 0.44 without A without A ○ ○ Example 2 0.078 0.067 0.86 0.44 without A without A ○ ○ Example 3 0.066 0.067 1.02 0.47 without A without A ○ ○ Example 4 0.043 0.067 1.56 0.57 without A without A ○ ○ Example 5 0.035 0.067 1.91 0.63 small B small B ○ ○ Example 6 0.062 0.055 0.89 0.44 without A without A ○ ○ Example 7 0.031 0.103 3.32 0.62 without A without A ○ ○ Example 8 0.078 0.067 0.86 0.44 small B small B ○ ○ Comparative example 1 0.017 0.067 3.94 0.72 Big C Big C X ○ Comparative example 2 0.078 0.055 0.71 0.44 without A without A ○ X Comparative example 3 0.657 0.055 0.08 1.72 Big C Big C ○ ○

It can be confirmed from Table 2 that when the AI ratio and the loss tangent of the intermediate layer are within the above range, even when a wafer with unevenness is singulated by DBG and LDBG, the unevenness can be fully embedded and displaced by the wafer. The induced crack generation rate was low, and no glue residue was observed in the incision.

1: Protective sheet for semiconductor processing 10: Substrate 20: middle layer 30: Adhesive layer 30a: main side 40: buffer layer 101: Semiconductor wafer 101a: Noodles 102: bump

FIG. 1A is a schematic cross-sectional view showing an example of the protective sheet for semiconductor processing of the present embodiment. FIG. 1B is a schematic cross-sectional view showing another example of the protective sheet for semiconductor processing of the present embodiment. 2 is a schematic cross-sectional view showing a state in which the protective sheet for semiconductor processing of the present embodiment is attached to the circuit surface of the semiconductor wafer.

1: Protective sheet for semiconductor processing

10: Substrate

20: middle layer

30: Adhesive layer

30a: main side

Claims (8)

A protective sheet for semiconductor processing, which has a base material and sequentially has an intermediate layer and an adhesive layer on one main surface of the base material, and satisfies the following (a) and (b): (a) The loss tangent of the intermediate layer at 50°C measured at a frequency of 1 Hz is 0.40 or more and 0.65 or less; (b) The ratio [A/I] of the storage modulus A of the adhesive layer to the storage modulus I of the intermediate layer at 50°C measured at a frequency of 1 Hz is 0.80 or more and 3.50 or less. The protective sheet for semiconductor processing according to claim 1, wherein a buffer layer is provided on the other main surface of the base material. The protective sheet for semiconductor processing according to claim 1 or 2, wherein the Young's modulus of the base material is 1000 MPa or more. The protective sheet for semiconductor processing according to any one of claims 1 to 3, wherein the thickness of the intermediate layer is 60 μm or more and 250 μm or less. The protective sheet for semiconductor processing according to any one of claims 1 to 4, wherein the adhesive layer is energy ray curable. The protective sheet for semiconductor processing according to any one of claims 1 to 5, wherein the intermediate layer is energy ray curable. The protective sheet for semiconductor processing according to any one of claims 1 to 6, wherein the semiconductor wafer is polished on the back surface of the semiconductor wafer having grooves formed on the surface of the semiconductor wafer, and the semiconductor wafer is polished by the polishing. In the step of singulating into a semiconductor wafer, the protective sheet for semiconductor processing is attached to the surface of the semiconductor wafer and used. A method for manufacturing a semiconductor device, which has: A step of attaching the protective sheet for semiconductor processing according to any one of claims 1 to 7 to the surface of a semiconductor wafer having unevenness; A step of forming a trench from the surface side of the semiconductor wafer, or a step of forming a modified region inside the semiconductor wafer from the surface or back of the semiconductor wafer; The semiconductor wafer on which the protective sheet for semiconductor processing is attached on the surface and the trench or the modified region is formed is polished from the back side, and the trench or the modified region is The step of singulating the starting point into multiple wafers; and The step of peeling the protective sheet for semiconductor processing from the singulated semiconductor wafer.

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