TWI838454B - Expanding method and manufacturing method of semiconductor device - Google Patents

Abstract

The present invention relates to an expansion method, which comprises attaching a first adhesive sheet (10) having a first adhesive layer (12) and a first substrate (11) to the first wafer surface (W1) of a wafer (W) having a first wafer surface (W1) and a second wafer surface (W3), attaching a second adhesive sheet having a second adhesive layer and a second substrate to the second wafer surface (W3), and cutting a cut from the side of the first adhesive sheet (10). , cutting the first adhesive sheet (10), further singulating the wafer (W) into a plurality of chips (CP), attaching a third adhesive sheet (30) having a third adhesive layer (32) and a third substrate (31) to the first substrate (11), peeling the second adhesive sheet from the second wafer surface (W3) of the wafer (W), stretching the third adhesive sheet (30), and expanding the interval between the plurality of chips (CP).

Description

Expanding method and manufacturing method of semiconductor device

The present invention relates to an expansion method and a method for manufacturing a semiconductor device.

In recent years, electronic devices have been miniaturized, lightweight, and highly functional. Semiconductor devices installed in electronic devices are also required to be miniaturized, thin, and high-density. Semiconductor chips are sometimes installed in packages close to their size. Such packages are also called chip scale packages (CSP). One example of CSP is wafer level package (WLP). In WLP, external electrodes are formed on the wafer before singulation by dicing, and the wafer is finally diced and singulated. Examples of WLP are fan-in and fan-out. In a fan-out WLP (hereinafter also referred to as "FO-WLP"), a semiconductor chip is covered with a sealing member in an area larger than the chip size to form a sealed body of the semiconductor chip. Not only a redistribution layer and external electrodes are formed on the electrical surface of the semiconductor chip, but also on the surface area of the sealing member.

For example, document 1 (International Publication No. 2010/058646) describes a method for manufacturing a semiconductor package in which a plurality of semiconductor chips singulated from a semiconductor wafer are left with their circuit forming surfaces, and are surrounded by a molding member to form an expanded wafer, and a redistribution pattern is formed in an area outside the semiconductor chip. In the manufacturing method described in document 1, before the plurality of semiconductor chips singulated are surrounded by the molding member, they are replaced with an expansion wafer adhesive tape, so that the wafer adhesive tape is extended to expand the distance between the plurality of semiconductor chips.

Furthermore, document 2 (Japanese Patent Publication No. 2017-076748) describes an adhesive sheet having a second base layer, a first base layer, and a first adhesive layer in sequence, and the second base layer has a fracture elongation of 400% or more. The method for manufacturing a semiconductor device described in document 2 includes the steps of adhering a semiconductor wafer to the first adhesive layer of the adhesive sheet, singulating the semiconductor wafer by dicing to form a plurality of semiconductor chips, and stretching the adhesive sheet to increase the spacing between the semiconductor chips.

The tape used in the expansion step usually has an adhesive layer for fixing the semiconductor chip on the tape and a base material for supporting the adhesive layer. When the expansion wafer adhesive tape described in Document 1 is stretched, not only the base material of the tape is stretched, but also the adhesive layer is stretched. After the expansion step, when the semiconductor chip is peeled off from the adhesive layer, there are cases where defects of the adhesive layer are generated on the surface of the semiconductor chip in contact with the adhesive layer. Such defects are sometimes referred to as residual smear in this specification.

Furthermore, when the expansion step is performed using the adhesive sheet described in Document 2, it is believed that it is difficult to generate residual smear because the adhesive layer in contact with the semiconductor chip is not stretched. However, since the adhesive sheet described in Document 2 is a tape structure in which the second substrate layer, the first substrate layer, and the first adhesive layer are combined, an expansion method that can prevent residual smear by using a simpler tape structure is eagerly expected. Furthermore, the process described in Document 2 is to cut the semiconductor wafer on the adhesive sheet without transferring it to other adhesive sheets, and directly stretch the adhesive sheet to perform the expansion step. Therefore, the cutting depth of the cutting blade must be carefully controlled so that the cutting blade does not reach the second substrate layer during cutting. Therefore, an expanded method that can prevent smearing by a simpler method is also eagerly expected.

Furthermore, in the expansion method, the adherend supported on the adhesive sheet is not only a semiconductor chip, but also a semiconductor device such as a wafer, a semiconductor device package, and a micro LED. Similar to the semiconductor chip, the intervals between the semiconductor devices may be expanded.

The object of the present invention is to provide an expansion method that can simplify the tape structure and manufacturing process and suppress smearing compared with the past, and to provide a manufacturing method of a semiconductor device including the expansion method.

According to one aspect of the present invention, an expansion method is provided, which is to attach a first adhesive sheet having a first adhesive layer and a first substrate to the first wafer surface of a wafer having a first wafer surface and a second wafer surface on the opposite side of the first wafer surface, attach a second adhesive sheet having a second adhesive layer and a second substrate to the second wafer surface, cut an incision from the side of the first adhesive sheet, cut the first adhesive sheet, further singulate the wafer into a plurality of chips, attach a third adhesive sheet having a third adhesive layer and a third substrate to the first substrate, peel off the second adhesive sheet from the second wafer surface of the wafer, stretch the third adhesive sheet, and expand the interval between the plurality of chips.

In an expansion method of one aspect of the present invention, it is preferred that the aforementioned cut is formed with a depth from the side of the aforementioned first adhesive sheet to the aforementioned second adhesive sheet. In an expansion method of one aspect of the present invention, it is preferred that the aforementioned second wafer surface is a surface formed by grinding the back side of the aforementioned wafer. In an expansion method of one aspect of the present invention, it is preferred that the aforementioned first adhesive sheet is adhered to the aforementioned first wafer surface before the aforementioned wafer is ground on the back side. In an expansion method of one aspect of the present invention, it is preferred that the aforementioned fourth adhesive sheet is adhered to the aforementioned first wafer surface before the aforementioned wafer is ground on the back side, and after grinding on the back side, the aforementioned fourth adhesive sheet is peeled off from the aforementioned first wafer surface, and the aforementioned first adhesive sheet is adhered to the aforementioned first wafer surface. In an expansion method of one aspect of the present invention, it is preferred that the fourth adhesive sheet is a back grinding sheet, the first adhesive sheet is a surface protection sheet, and the thickness of the surface protection sheet is greater than 5 μm and less than 500 μm. In an expansion method of one aspect of the present invention, it is preferred that the first adhesive sheet is a back grinding sheet. In an expansion method of one aspect of the present invention, it is preferred that the third adhesive sheet is an expansion sheet. In an expansion method of one aspect of the present invention, it is preferred that the wafer is a semiconductor wafer. In an expansion method of one aspect of the present invention, it is preferred that the first wafer surface has a circuit. According to one aspect of the present invention, a method for manufacturing a semiconductor device is provided, which includes the expansion method of one aspect of the present invention.

According to one aspect of the present invention, a method for expanding a semiconductor device including the method for expanding a semiconductor device capable of suppressing smear can be provided.

[First embodiment] The following describes the expansion method of the present embodiment and the method for manufacturing a semiconductor device including the expansion method. Figure 1 (Figure 1A and Figure 1B), Figure 2 (Figure 2A and Figure 2B) and Figure 3 are cross-sectional schematic diagrams illustrating the method for manufacturing a semiconductor device including the expansion method of the present embodiment. The expansion method of the present embodiment includes at least the following steps (P1) to (P5). (P1) A step of preparing a wafer having a first adhesive sheet attached to a first wafer surface and a second adhesive sheet attached to a second wafer surface. The first adhesive sheet has a first adhesive layer and a first substrate, and the second adhesive sheet has a second adhesive layer and a second substrate. (P2) Cutting the first adhesive sheet from the side, cutting the first adhesive sheet, and further cutting the wafer into a plurality of chips. (P3) A step of attaching a third adhesive sheet to the first substrate. The third adhesive sheet has a third adhesive layer and a third substrate. (P4) A step of peeling the second adhesive sheet from the second wafer surface of the wafer. (P5) A step of stretching the third adhesive sheet to expand the interval between the plurality of chips. FIG. 1A is a diagram for explaining step (P1). FIG. 1A shows a wafer W to which the first adhesive sheet 10 and the second adhesive sheet 20 are attached.

The semiconductor wafer W has a first wafer surface W1 as a first wafer surface and a second wafer surface W3 as a back surface. A circuit W2 is formed on the first wafer surface W1. The first adhesive sheet 10 is attached to the first wafer surface W1. The second adhesive sheet 20 is attached to the back surface W3. The first adhesive sheet 10 has a first adhesive layer 12 and a first substrate 11. The second adhesive sheet 20 has a second adhesive layer 22 and a second substrate 21. The details of the first adhesive sheet 10 and the second adhesive sheet 20 will be described later. The semiconductor wafer W may be, for example, a silicon wafer, or a compound semiconductor wafer of gallium, arsenic, etc. As a method of forming the circuit W2 on the circuit surface W1 of the semiconductor wafer W, there are widely used methods such as etching and lift-off.

[Back grinding step] The semiconductor wafer W prepared in step (P1) is preferably a wafer obtained by a back grinding step. In the back grinding step, the surface of the semiconductor wafer W on the opposite side to the circuit surface W1 is ground to a specific thickness. The back surface W3 is preferably a surface formed by grinding the back surface of the semiconductor wafer W. The surface exposed after grinding the semiconductor wafer W is the back surface W3. The method for grinding the semiconductor wafer W is not particularly limited, and examples thereof include known methods such as using a grinder. When grinding the semiconductor wafer W, in order to protect the circuit W2, it is preferred to stick an adhesive sheet called a back grinding sheet to the circuit surface W1. The back grinding of the wafer is to fix the electrical surface W1 side of the semiconductor wafer W, that is, the back grinding sheet side, by a fixture table, etc., and grind the back side where no circuit is formed by a grinder. In this embodiment, the first adhesive sheet 10 is preferably a back grinding sheet. When the first adhesive sheet 10 is used as the back grinding sheet, the semiconductor wafer W is pasted with the electrical surface W1 facing the first adhesive layer 12 of the first adhesive sheet 10. Before back grinding the semiconductor wafer W, it is preferred to paste the first adhesive sheet 10 as the back grinding sheet on the electrical surface W1 as the first wafer surface. The step of pasting the first adhesive sheet 10 on the electrical surface W1 is sometimes referred to as the pasting step of the first adhesive sheet. The thickness of the semiconductor wafer W before grinding is not particularly limited, but is usually between 500 μm and 1000 μm. The thickness of the semiconductor wafer W after grinding is not particularly limited, but is usually between 20 μm and 500 μm.

[Step of pasting the second adhesive sheet] The semiconductor wafer W prepared in step (P1) is preferably a wafer obtained by a back grinding step and then a pasting step of pasting the second adhesive sheet 20 on the back surface W3. This pasting step is sometimes referred to as a pasting step of the second adhesive sheet. As described later, in step (P2), the semiconductor wafer W is singulated into a plurality of semiconductor chips CP by dicing. When the semiconductor wafer W is cut, an adhesive sheet called a dicing sheet is preferably pasted on the back surface W3 in order to hold the semiconductor wafer W. In this embodiment, the second adhesive sheet 20 is preferably a dicing sheet. When the second adhesive sheet 20 is used as a dicing sheet, the semiconductor wafer W is attached with the back surface W3 facing the second adhesive layer 22 of the second adhesive sheet 20 .

[Cutting step] Figure 1B is a diagram for explaining step (P2). Step (P2) is sometimes referred to as a cutting step. Figure 1B shows a plurality of semiconductor chips CP held on the second adhesive sheet 20. The semiconductor wafer W in a state where the first adhesive sheet 10 is attached to the electrical surface W1 and the second adhesive sheet 20 is attached to the back surface W3 is singulated by cutting to form a plurality of semiconductor chips CP. In this embodiment, a cut is made from the side of the first adhesive sheet 10, the first adhesive sheet 10 is cut, and then the semiconductor wafer W is cut. After the cutting step, the electrical surface W1 of the plurality of semiconductor chips CP is respectively covered by the cut first adhesive sheet 10. Cutting is performed using a cutting mechanism such as a cutting saw. The cutting depth during cutting is not particularly limited as long as it is a depth that can separate the first adhesive sheet 10 and the semiconductor wafer W. From the perspective of surely cutting the semiconductor wafer W, the cut in the cutting step is preferably formed to a depth from the side of the first adhesive sheet 10 to the second adhesive sheet 20, and more preferably to the second adhesive layer 22 of the second adhesive sheet 20. By cutting, the second adhesive layer 22 is also cut to the same size as the semiconductor chip CP. Furthermore, there may be a situation where a cut is also formed in the second substrate 21 by cutting.

[Standing step of the third adhesive sheet] Figure 2A is a diagram for explaining step (P3). Step (P3) is sometimes referred to as the step of sticking the third adhesive sheet. Figure 2A shows a state where the third adhesive sheet 30 is stuck to the plurality of semiconductor chips CP obtained by the cutting step. The third adhesive sheet 30 has a third adhesive layer 32 and a third substrate 31. The details of the third adhesive sheet 30 are described later. In this embodiment, when the third adhesive sheet 30 is stuck to the surface W1 side of the plurality of semiconductor chips CP, a laminated structure of the first adhesive sheet 10 singulated between the plurality of semiconductor chips CP and the third adhesive layer 32 of the third adhesive sheet 30 is obtained.

[Step of peeling off the second adhesive sheet] Figure 2B is a diagram for explaining step (P4). This step (P4) is sometimes referred to as the step of peeling off the second adhesive sheet. Figure 2B shows the state of peeling off the second adhesive sheet 20 from the back side W3 of the wafer W after the third adhesive sheet 30 is pasted. After the third adhesive sheet 30 is pasted, when the second adhesive sheet 20 is peeled off, the back side W3 of the plurality of semiconductor chips CP is exposed. In addition, when an energy ray polymerizable compound is prepared in the second adhesive layer 22, it is preferred to irradiate the second adhesive layer 22 with energy rays from the second substrate 21 side, and after the energy ray polymerizable compound is cured, the second adhesive sheet 20 is peeled off.

[Expansion step] Figure 3 is a diagram for explaining step (P5). Step (P5) is sometimes referred to as the expansion step. Figure 3 shows a state in which the third adhesive sheet 30 is stretched to expand the interval between the plurality of semiconductor chips CP after the second adhesive sheet 20 is peeled off. When expanding the interval between the plurality of semiconductor chips CP, it is preferable to stretch the expansion sheet while holding the plurality of semiconductor chips CP by an adhesive sheet called an expansion sheet. In this embodiment, the third adhesive sheet 30 is preferably an expansion sheet. The method of stretching the third adhesive sheet 30 in the expansion step is not particularly limited. Examples of methods for stretching the third adhesive sheet 30 include a method of stretching the first adhesive sheet 10 by pressing a ring-shaped or circular expander, and a method of pinching the outer periphery of the third adhesive sheet 30 and stretching it using a holding member. In this embodiment, the spacing D1 between the plurality of semiconductor chips CP is not specifically limited because it depends on the size of the semiconductor chip CP. In particular, the spacing D1 between adjacent semiconductor chips CP of the plurality of semiconductor chips CP affixed to one side of the adhesive sheet is preferably greater than 200 μm. In addition, the upper limit of the spacing between the semiconductor chips CP is not specifically limited. The upper limit of the spacing between the semiconductor chips CP may be, for example, 6000 μm.

[First transfer step] In this embodiment, after the expansion step, a step of transferring the plurality of semiconductor chips CP adhered to the third adhesive sheet 30 to another adhesive sheet (e.g., the fifth adhesive sheet) (hereinafter sometimes referred to as the "first transfer step") may also be implemented. FIG. 4A shows a diagram illustrating a step of transferring the plurality of semiconductor chips CP adhered to the third adhesive sheet 30 to the fifth adhesive sheet 50 (hereinafter sometimes referred to as the "transfer step"). The fifth adhesive sheet 50 is not particularly limited as long as it can hold the plurality of semiconductor chips CP. The fifth adhesive sheet 50 has a fifth substrate 51 and a fifth adhesive layer 52. When the transfer step is performed in this embodiment, it is preferred that, for example, after the expansion step, the fifth adhesive sheet 50 is adhered to the back surface W3 of the plurality of semiconductor chips CP, and then the third adhesive sheet 30 is peeled off. The fifth adhesive sheet 50 may also be adhered to the second annular frame together with the plurality of semiconductor chips CP. In this case, the second annular frame is placed on the fifth adhesive layer 52 of the fifth adhesive sheet 50, and is lightly pressed and fixed. Subsequently, the fifth adhesive layer 52 exposed on the inner side of the annular shape of the second annular frame is pressed against the back surface W3 of the semiconductor chip CP, and the plurality of semiconductor chips CP are fixed to the fifth adhesive sheet 50. FIG. 4B shows a diagram illustrating the step of peeling off the third adhesive sheet 30 after the fifth adhesive sheet 50 is adhered.

In this embodiment, the first adhesive sheet 10 and the third adhesive sheet 30 that are singulated and cover the electrical path W1 of the semiconductor chip CP are peeled off together when the third adhesive sheet 30 is peeled off as an example. The force for peeling off the third adhesive sheet 30 from the first adhesive sheet 10 is preferably greater than the force for peeling off the first adhesive sheet 10 from the electrical path W1 of the semiconductor chip CP. In addition, the first adhesive sheet 10 that is singulated and covers the electrical path W1 may remain on the semiconductor chip CP and only the third adhesive sheet 30 may be peeled off. After the fifth adhesive sheet 50 is attached, the first adhesive sheet 10 and the third adhesive sheet 30 are peeled off to expose the electrical path W1 of the plurality of semiconductor chips CP. After the first adhesive sheet 10 and the third adhesive sheet 30 are peeled off, the interval D1 between the plurality of semiconductor chips CP expanded in the expansion step is preferably maintained.

[Second transfer step] FIG. 5A shows a diagram illustrating a step of transferring a plurality of semiconductor chips CP adhered to the fifth adhesive sheet 50 to the sixth adhesive sheet 60 (hereinafter sometimes referred to as the "second transfer step"). The plurality of semiconductor chips CP transferred from the fifth adhesive sheet 50 to the sixth adhesive sheet 60 preferably maintains the interval D1 between the semiconductor chips CP. The sixth adhesive sheet 60 is not particularly limited as long as it can hold the plurality of semiconductor chips CP. The sixth adhesive sheet 60 has a sixth substrate 61 and a sixth adhesive layer 62. When the plurality of semiconductor chips CP on the sixth adhesive sheet 60 is to be sealed, it is preferred to use an adhesive sheet for the sealing step as the sixth adhesive sheet 60, and it is more preferred to use an adhesive sheet having heat resistance. Furthermore, when a heat-resistant adhesive sheet is used as the sixth adhesive sheet 60, the sixth substrate 61 and the sixth adhesive layer 62 are preferably formed of heat-resistant materials that can withstand the temperature experienced in the sealing step. The plurality of semiconductor chips CP transferred from the fifth adhesive sheet 50 to the sixth adhesive sheet 60 are adhered with the electrical path W1 facing the sixth adhesive layer 62.

[Sealing step] FIG. 5B shows a diagram illustrating a step of sealing a plurality of semiconductor chips CP using a sealing member 300 (hereinafter sometimes referred to as a "sealing step"). In the present embodiment, the sealing step is performed after the plurality of semiconductor chips CP are transferred to the sixth adhesive sheet 60. In the sealing step, a sealed body 3 is formed by covering the plurality of semiconductor chips CP with the sealing member 300 while the electrical path W1 is protected by the sixth adhesive sheet 60. The sealing member 300 is also filled between the plurality of semiconductor chips CP. Since the electrical path W1 and the circuit W2 are covered by the sixth adhesive sheet 60, the electrical path W1 can be prevented from being covered by the sealing member 300.

Through the sealing step, a sealing body 3 is obtained in which a plurality of semiconductor chips CP separated by a specific distance are buried in the sealing member 300. In the sealing step, the plurality of semiconductor chips CP are preferably covered by the sealing member 300 to maintain the state of the interval D1 after the expansion step. After the sealing step, the sixth adhesive sheet 60 is peeled off. When the sixth adhesive sheet 60 is peeled off, the electrical surface W1 of the semiconductor chip CP and the surface 3A of the sealing body 3 in contact with the sixth adhesive sheet 60 are exposed. After the aforementioned expansion step, by repeating the transfer step and the expansion step any number of times, the distance between the semiconductor chips CP can be set to a desired distance, and the direction of the electrical path between the sealed semiconductor chips CP can be set to a desired direction.

[Other steps] After the adhesive sheet is peeled off from the sealing body 3, the sealing body 3 is subjected to a redistribution layer forming step of forming a redistribution layer electrically connected to the semiconductor chip CP and a connection step of electrically connecting the redistribution layer to the external terminal electrode. By the redistribution layer forming step and the connection step to the external terminal electrode, the circuit of the semiconductor chip CP is electrically connected to the external terminal electrode. The sealing body 3 connected to the external terminal electrode is singulated in semiconductor chip CP units. The method of singulating the sealing body 3 is not particularly limited. By singulating the sealing body 3, a semiconductor package of semiconductor chip CP units is manufactured. A semiconductor package having external electrodes connected by fanning out outside the area of the semiconductor chip CP is manufactured as a fan-out wafer-level package (FO-WLP).

(First adhesive sheet) The first adhesive sheet 10 has a first substrate 11 and a first adhesive layer 12. The first adhesive layer 12 is laminated on the first substrate 11. ・First substrate The first substrate 11 of this embodiment is not particularly limited in its constituent material as long as it can play an appropriate function in the desired step such as the expansion step. The first substrate 11 is preferably composed of a film mainly composed of a resin material. Examples of films mainly composed of a resin material include ethylene copolymer films, polyolefin films, polyvinyl chloride films, polyester films, polyurethane films, polyimide films, polystyrene films, polycarbonate films, and fluororesin films. Examples of the ethylene-based copolymer film include an ethylene-vinyl acetate copolymer film, an ethylene-(meth)acrylic acid copolymer film, and an ethylene-(meth)acrylate copolymer film.

In this specification, (meth)acrylic acid means both acrylic acid and methacrylic acid, and the same applies to other similar terms. Examples of polyolefin-based films include polyethylene films, polypropylene films, polybutylene films, polybutadiene films, polymethylpentene films, ethylene-norbornene copolymer films, and norbornene resin films. Examples of polyethylene films include low-density polyethylene (LDPE) films, linear low-density polyethylene (LLDPE) films, and high-density polyethylene (HDPE) films. Examples of polyvinyl chloride-based films include polyvinyl chloride films and vinyl chloride copolymer films. Examples of polyester films include polyethylene terephthalate films and polybutylene terephthalate films. Examples of the first substrate 11 include crosslinked films of films with resin-based materials as the main material. In addition, examples of the first substrate include modified films such as ionic polymer films. The first substrate 11 may be a film composed of only one type selected from the group consisting of a film mainly composed of a resin-based material, a crosslinked film, and a modified film, or may be a laminated film composed of two or more types.

In the first substrate 11, at least one additive selected from the group consisting of, for example, pigments, flame retardants, plasticizers, antistatic agents, lubricants, and fillers may also be included in the above-mentioned film with resin materials as the main material. Examples of pigments include titanium dioxide and carbon black. Examples of fillers include organic materials such as melamine resins, inorganic materials such as fuming silica, and metal materials such as nickel particles. The content of additives contained in the film with resin materials as the main material is not particularly limited, but is preferably limited to a range that enables the first substrate to perform the desired function without losing smoothness and softness. When ultraviolet rays are irradiated as energy rays for curing the first adhesive layer 12, the first substrate is preferably transparent to the ultraviolet rays. When electron beams are irradiated as energy rays for curing the first adhesive layer 12, the first substrate is preferably transparent to the electron beams.

The first substrate 11 may be subjected to surface treatment or primer treatment on one or both sides as desired in order to improve the adhesion of the first adhesive layer 12 laminated on the surface thereof. Examples of surface treatment include oxidation and embossing. Examples of primer treatment include methods of forming a primer layer on the surface of the substrate. Examples of oxidation methods include corona discharge treatment, plasma discharge treatment, chromium oxidation treatment (wet), flame treatment, hot air treatment, ozone treatment, and ultraviolet irradiation treatment. Examples of embossing methods include sandblasting and thermal spraying. The thickness of the first substrate 11 is not particularly limited as long as the first adhesive sheet can function properly in the desired step. The thickness of the first substrate 11 is preferably 20 μm or more, more preferably 25 μm or more, and even more preferably 50 μm or more. In addition, the thickness of the first substrate 11 is preferably 450 μm or less, more preferably 400 μm or less, and even more preferably 350 μm or less.

・First adhesive layer The first adhesive layer 12 is not particularly limited in terms of its constituent material as long as it can perform an appropriate function in a desired step such as a back grinding step. In the present embodiment, the first adhesive layer 12 is preferably composed of at least one adhesive selected from the group consisting of, for example, acrylic adhesives, urethane adhesives, polyester adhesives, rubber adhesives, and silicone adhesives, and more preferably composed of acrylic adhesives. The first adhesive layer 12 preferably contains an energy ray-curable adhesive. The energy ray-curable adhesive contains an energy ray-curable compound. When the first adhesive layer 12 contains an energy ray curable adhesive, the energy ray is irradiated to the first adhesive layer 12 from the first substrate 11 side to cure the energy ray polymerizable compound. When the energy ray polymerizable compound is cured, the cohesive force of the first adhesive layer 12 is increased, and the adhesion between the first adhesive layer 12 and the adherend (semiconductor wafer W or semiconductor chip CP) can be reduced or eliminated. Examples of energy rays include ultraviolet rays (UV) and electron beams (EB), and ultraviolet rays are preferred.

Examples of energy ray-curable adhesives include "X-type adhesive composition", "Y-type adhesive composition" and "XY-type adhesive composition". "X-type adhesive composition" is an energy ray-curable adhesive composition comprising a non-energy ray-curable adhesive resin (also referred to as "adhesive resin I") and an energy ray-curable compound other than the adhesive resin. "Y-type adhesive composition" is an energy ray-curable adhesive composition comprising an energy ray-curable adhesive resin (hereinafter also referred to as "adhesive resin II") as an energy ray-curable adhesive in which an unsaturated group is introduced into the side chain of the non-energy ray-curable adhesive resin as a main component, and does not contain an energy ray-curable compound other than the adhesive resin. The "XY type adhesive composition" is a combination of the X type and the Y type, that is, an energy ray-hardening adhesive composition comprising an energy ray-hardening adhesive resin II and an energy ray-hardening compound other than the adhesive resin.

Among them, it is preferable to use an XY type adhesive composition. By using an XY type adhesive composition, sufficient adhesive properties are obtained before curing, and on the other hand, the peeling force on the semiconductor wafer or semiconductor chip can be sufficiently reduced after curing. However, the adhesive as the first adhesive layer 12 can be formed from a non-energy ray-curable adhesive composition that does not cure even when irradiated with energy rays. The non-energy ray-curable adhesive composition is an adhesive composition that contains at least a non-energy ray-curable adhesive resin I, and on the other hand does not contain the above-mentioned energy ray-curable adhesive resin II and energy ray-curable compound. In addition, in the following description, "adhesive resin" is used to refer to one or both of the above-mentioned adhesive resin I and adhesive resin II. Examples of specific adhesive resins include acrylic resins, urethane resins, rubber resins, and silicone resins, and acrylic resins are preferred. The following describes in more detail acrylic adhesives using acrylic resins as adhesive resins.

・Acrylic polymer (a) Acrylic polymer (a) is used as the acrylic resin. Acrylic polymer (a) is a polymer obtained by polymerizing a monomer containing at least an alkyl (meth)acrylate. Acrylic polymer (a) contains constituent units derived from an alkyl (meth)acrylate. The carbon number of the alkyl group in the alkyl (meth)acrylate is preferably 1 or more and 20 or less. The alkyl group in the alkyl (meth)acrylate may be a straight chain or a branched chain. Specific examples of the alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, and dodecyl (meth)acrylate. The (meth)acrylic acid alkyl esters may be used alone or in combination of two or more.

From the viewpoint of improving the adhesive force of the adhesive layer, the acrylic polymer (a) preferably contains a constituent unit derived from an alkyl (meth)acrylate having an alkyl carbon number of 4 or more. The alkyl carbon number of the alkyl (meth)acrylate is preferably 4 or more and 12 or less, and more preferably 4 or more and 6 or less. The alkyl (meth)acrylate having an alkyl carbon number of 4 or more is preferably an alkyl acrylate. In the acrylic polymer (a), the alkyl (meth)acrylate having an alkyl carbon number of 4 or more is preferably 40% by mass to 98% by mass, more preferably 45% by mass to 95% by mass, and even more preferably 50% by mass to 90% by mass, relative to the total amount of monomers constituting the acrylic polymer (a) (hereinafter also referred to as "total monomer amount"). The acrylic polymer (a) is preferably a copolymer containing, in addition to the constituent units derived from the (meth)acrylic acid alkyl ester having an alkyl group with a carbon number of 4 or more, constituent units derived from the (meth)acrylic acid alkyl ester having an alkyl group with a carbon number of 1 or more and a carbon number of 3 or less, in order to adjust the elastic modulus or adhesive properties of the adhesive layer. The (meth)acrylic acid alkyl ester is preferably a (meth)acrylic acid alkyl ester having a carbon number of 1 or 2, more preferably methyl (meth)acrylate, and most preferably methyl methacrylate. In the acrylic polymer (a), the (meth)acrylic acid alkyl ester having an alkyl group with a carbon number of 1 or more and a carbon number of 3 or less is preferably 1 mass % or more and 30 mass % or less, more preferably 3 mass % or more and 26 mass % or less, and even more preferably 6 mass % or more and 22 mass % or less, relative to the total amount of monomers.

・Functional group-containing monomers In addition to the constituent units derived from the above-mentioned (meth) alkyl acrylate, the acrylic polymer (a) preferably has constituent units derived from functional group-containing monomers. Examples of functional groups of the functional group-containing monomers include hydroxyl groups, carboxyl groups, amino groups, and epoxy groups. The functional group-containing monomers can react with the crosslinking agent described below to become a crosslinking starting point, and react with the unsaturated group-containing compound to introduce an unsaturated group into the side chain of the acrylic polymer (a). Examples of functional group-containing monomers include hydroxyl group-containing monomers, carboxyl group-containing monomers, amino group-containing monomers, and epoxy group-containing monomers. These functional group-containing monomers can be used alone or in combination of two or more. Among the functional group-containing monomers, hydroxyl group-containing monomers and carboxyl group-containing monomers are preferred, and hydroxyl group-containing monomers are more preferred.

Examples of monomers containing a hydroxyl group include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and the like; unsaturated alcohols such as vinyl alcohol and allyl alcohol, and the like. Examples of monomers containing a carboxyl group include ethylenically unsaturated monocarboxylic acids such as (meth)acrylic acid and crotonic acid; ethylenically unsaturated dicarboxylic acids such as fumaric acid, itaconic acid, maleic acid, citric acid, and the like, and their anhydrides; and 2-carboxyethyl methacrylate, and the like. The amount of the monomer containing a functional group is preferably from 1 mass % to 35 mass %, more preferably from 3 mass % to 32 mass %, and even more preferably from 6 mass % to 30 mass %, based on the total amount of monomers constituting the acrylic polymer (a).

In addition to the above, the acrylic polymer (a) may also contain constituent units derived from monomers copolymerizable with the acrylic monomers. Examples of constituent units derived from monomers copolymerizable with the acrylic monomers include styrene, α-methylstyrene, vinyltoluene, vinyl formate, vinyl acetate, acrylonitrile and acrylamide. The acrylic polymer (a) can be used as a non-energy ray-curable adhesive resin I (acrylic resin). In addition, as an energy ray-curable acrylic resin, an example is one in which the functional group of the acrylic polymer (a) is reacted with a compound having a photopolymerizable unsaturated group (also referred to as an unsaturated group-containing compound). The unsaturated group-containing compound is a compound having both a substituent that can bond to the functional group of the acrylic polymer (a) and a photopolymerizable unsaturated group. Examples of the photopolymerizable unsaturated group include a (meth)acryl group, a vinyl group, an allyl group and a vinylbenzyl group, and a (meth)acryl group is preferred.

In addition, examples of substituents that can bond to functional groups in compounds containing unsaturated groups include isocyanate groups and glyceryl groups. Therefore, examples of compounds containing unsaturated groups include (meth)acryloyloxyethyl isocyanate, (meth)acryloyl isocyanate, and (meth)acrylate glyceryl ester. In addition, the unsaturated group-containing compound preferably reacts with a portion of the functional groups of the acrylic polymer (a). Specifically, preferably, more than 50 mol% and less than 98 mol% of the functional groups of the acrylic polymer (a) react with the unsaturated group-containing compound, and more preferably, more than 55 mol% and less than 93 mol% react with the unsaturated group-containing compound. Thus, in the energy-ray-curable acrylic resin, a part of the functional groups remain without reacting with the unsaturated group-containing compound, and are easily crosslinked by the crosslinking agent. In addition, the weight average molecular weight (Mw) of the acrylic resin is preferably 300,000 to 1.6 million, more preferably 400,000 to 1.4 million, and even more preferably 500,000 to 1.2 million. The weight average molecular weight (Mw) of the acrylic resin is a value converted to polystyrene measured by gel permeation chromatography (GPC).

・Energy ray-hardening compound The energy ray-hardening compound contained in the X-type or XY-type adhesive composition is preferably a monomer or oligomer having an unsaturated group in the molecule and capable of being polymerized and hardened by energy ray irradiation. Examples of such energy ray-hardening compounds include poly(meth)acrylate monomers such as trihydroxymethylpropane tri(meth)acrylate, pentaerythritol (meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butanediol di(meth)acrylate, and 1,6-hexanediol (meth)acrylate, and oligomers such as urethane (meth)acrylate oligomers, polyester (meth)acrylate, polyether (meth)acrylate, and epoxy (meth)acrylate. Among them, urethane (meth) acrylate oligomers are preferred because they have a relatively high molecular weight and are less likely to reduce the shear storage modulus of the adhesive layer. The molecular weight of the energy ray-curable compound (weight average molecular weight in the case of oligomers) is preferably 100 to 12,000, more preferably 200 to 10,000, still more preferably 400 to 8,000, and particularly preferably 600 to 6,000.

The content of the energy ray-hardening compound in the X-type adhesive composition is preferably 40 to 200 parts by mass, more preferably 50 to 150 parts by mass, and even more preferably 60 to 90 parts by mass, relative to 100 parts by mass of the adhesive resin. On the other hand, the content of the energy ray-hardening compound in the XY-type adhesive composition is preferably 1 to 30 parts by mass, more preferably 2 to 20 parts by mass, and even more preferably 3 to 15 parts by mass, relative to 100 parts by mass of the adhesive resin. In the XY-type adhesive composition, since the adhesive resin is energy ray-hardening, even if the content of the energy ray-hardening compound is small, the peeling force can be sufficiently reduced after energy ray irradiation.

・Crosslinking agent The adhesive composition preferably further contains a crosslinking agent. The crosslinking agent reacts with the functional group derived from the functional group monomer of the adhesive resin to crosslink the adhesive resins. Examples of the crosslinking agent include isocyanate-based crosslinking agents such as toluene diisocyanate, hexamethylene diisocyanate, and adducts thereof; epoxy-based crosslinking agents such as ethylene glycol glycidyl ether; aziridine-based crosslinking agents such as hexa[1-(2-methyl)-aziridinyl]triphosphatriazine; chelate-based crosslinking agents such as aluminum chelates; etc. These crosslinking agents may be used alone or in combination of two or more. Among them, isocyanate-based crosslinking agents are preferred from the perspective of improving cohesion and adhesion, and from the perspective of ease of acquisition. The amount of the crosslinking agent, based on the perspective of promoting the crosslinking reaction, is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 7 parts by mass, and even more preferably 0.05 to 4 parts by mass, relative to 100 parts by mass of the adhesive resin.

・Photopolymerization initiator When the adhesive composition is energy-ray-curable, the adhesive composition preferably contains a photopolymerization initiator. By containing a photopolymerization initiator, the curing reaction of the adhesive composition can be fully carried out even with relatively low-energy energy such as ultraviolet rays. Examples of photopolymerization initiators include benzoin compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, thioxanone compounds, and peroxide compounds. Further examples of photopolymerization initiators include photosensitizers such as amines or quinones. More specific examples of photopolymerization initiators include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propane-1-one, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzylphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, diphenyl acyl, diacetyl, 8-chloroanthraquinone, and bis(2,4,6-trimethylbenzyl)phenylphosphine oxide. These photopolymerization initiators may be used alone or in combination of two or more. The amount of the photopolymerization initiator to be added is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 5 parts by mass, and even more preferably 0.05 to 5 parts by mass, relative to 100 parts by mass of the adhesive resin.

・Other additives The adhesive composition may also contain other additives within the scope that does not impair the effect of the present invention. Examples of other additives include antistatic agents, antioxidants, softeners (plasticizers), fillers, rustproofing agents, pigments and dyes. When preparing these additives, the amount of the additives is preferably not less than 0.01 parts by mass and not more than 6 parts by mass relative to 100 parts by mass of the adhesive resin. In addition, from the perspective of improving the coating properties on the substrate, buffer layer or release sheet, the adhesive composition can be further diluted with an organic solvent to be in the form of a solution of the adhesive composition (sometimes referred to as a coating liquid). Examples of the organic solvent include methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexane, n-hexane, toluene, xylene, n-propanol and isopropanol.

Furthermore, the organic solvents used in the synthesis of the adhesive resin can be directly used, and one or more organic solvents other than the organic solvents used in the synthesis can be added to uniformly apply the solution (coating liquid) of the adhesive composition. The thickness of the first adhesive layer 12 is preferably less than 200 μm, more preferably 5 μm or more and 80 μm or less, and more preferably 10 μm or more and 70 μm or less. When the thickness of the first adhesive layer 12 is within this range, the proportion of the lower rigidity portion of the first adhesive sheet 10 can be reduced, so it is easy to further prevent semiconductor chip defects generated during back sheet grinding. The above is a description of the first adhesive layer 12.

・Peeling sheet A peeling sheet may be attached to the surface of the first adhesive sheet 10. Specifically, the peeling sheet is attached to the surface of the first adhesive layer 12 of the first adhesive sheet 10. The peeling sheet protects the first adhesive layer 12 during transportation and storage by being attached to the surface of the first adhesive layer 12. The peeling sheet is releasably attached to the first adhesive sheet 10 and is peeled off and removed from the first adhesive sheet 10 before the first adhesive sheet 10 is used (i.e., before the back surface is ground). The peeling sheet is a peeling sheet that has been subjected to peeling treatment on at least one side. A specific example is a peeling sheet having a peeling sheet substrate and a peeling agent layer formed by coating a peeling agent on the surface of the substrate. The peeling sheet substrate is preferably a resin film. Examples of resins constituting the resin film as the peeling sheet substrate include polyester resin films such as polyethylene terephthalate diester resins, polybutylene terephthalate resins, and polyethylene naphthalate resins, and polyolefin resins such as polypropylene resins and polyethylene resins. Examples of the stripping agent include silicone resins, olefin resins, isoprene resins, butadiene resins, rubber elastomers, long-chain alkyl resins, alkyd resins, fluorine resins, etc. The thickness of the stripping sheet is not particularly limited, but is preferably 10 μm to 200 μm, and more preferably 20 μm to 150 μm.

・Manufacturing method of adhesive sheet The manufacturing method of the first adhesive sheet 10 and other adhesive sheets described in this specification is not particularly limited, and can be manufactured by a known method. For example, an adhesive layer provided on a release sheet is bonded to one side of a substrate, and an adhesive sheet with a release sheet attached to the surface of the adhesive layer can be manufactured. Furthermore, a buffer layer provided on the release sheet is bonded to the substrate, and the release sheet is removed to obtain a laminate of the buffer layer and the substrate. Furthermore, an adhesive layer provided on the release sheet is bonded to the substrate side of the laminate, and an adhesive sheet with a release sheet attached to the surface of the adhesive layer can be manufactured. Furthermore, when buffer layers are provided on both sides of the substrate, the adhesive layer is formed on the buffer layers. The peeling sheet attached to the surface of the adhesive layer can be appropriately peeled off and removed before the adhesive sheet is used. A more specific example of the manufacturing method of the adhesive sheet is as follows. First, an adhesive composition constituting the adhesive layer and a coating liquid containing a solvent or a dispersion medium as desired are prepared. Next, the coating liquid is applied to one side of the substrate by a coating mechanism to form a coating film. Examples of coating mechanisms include die coaters, curtain coaters, spray coaters, slit coaters, and scraper coaters. Next, by drying the coating film, an adhesive layer can be formed. The properties of the coating liquid are not particularly limited as long as it can be coated. The coating liquid may contain a component for forming an adhesive layer as a solute, or may contain a component for forming an adhesive layer as a dispersion medium. Similarly, the adhesive composition may be directly coated on one side of the substrate or on the buffer layer to form an adhesive layer.

Furthermore, as another more specific example of the manufacturing method of the adhesive sheet, the following method is given. First, a coating liquid is applied on the peeling surface of the aforementioned peeling sheet to form a coating film. Next, the coating film is dried to form a laminate composed of an adhesive layer and a peeling sheet. Next, a substrate is attached to the surface of the adhesive layer of the laminate opposite to the surface of the peeling sheet, and a laminate of an adhesive sheet and a peeling sheet can also be obtained. The peeling sheet in the laminate can also be peeled off as a step material, and the adhesive layer can be protected before the adherend (such as a semiconductor chip and a semiconductor wafer, etc.) is attached to the adhesive layer. In the case where the coating liquid contains a crosslinking agent, by changing the coating drying conditions (such as temperature and time, etc.) or by performing another heat treatment, for example, a crosslinking reaction between the (meth) acrylic copolymer and the crosslinking agent in the coating is carried out, and a crosslinking structure is formed in the adhesive layer with the desired density. In order to fully carry out the crosslinking reaction, after laminating the adhesive layer on the substrate by the above method, the obtained adhesive sheet can also be cured for several days in an environment of, for example, 23°C and a relative humidity of 50%. The thickness of the first adhesive sheet 10 is preferably 10μm or more, and more preferably 30μm or more. The thickness of the first adhesive sheet 10 is preferably 500μm or less, and more preferably 300μm or less.

(Second adhesive sheet) The second adhesive sheet 20 has a second substrate 21 and a second adhesive layer 22. The second adhesive layer 22 is laminated on the second substrate 21. ・Second substrate The second substrate 21 of this embodiment is not particularly limited in its constituent material as long as it performs an appropriate function in the desired step such as the cutting step. The second substrate 21 is preferably composed of a film mainly composed of a resin material. Examples of films mainly composed of a resin material include ethylene copolymer films, polyolefin films, polyvinyl chloride films, polyester films, polyurethane films, polyimide films, polystyrene films, polycarbonate films, and fluororesin films. Specific examples of films with resin materials as the main material that can be used as the second substrate 21 are the same as the films exemplified in the description of the first substrate 11. In addition, as the polyolefin film in the second substrate 21, in addition to the films exemplified in the description of the first substrate 11, ethylene-propylene copolymer films can also be used. Like the first substrate 11, the second substrate 21 can also contain at least one additive selected from the group consisting of, for example, pigments, flame retardants, plasticizers, antistatic agents, lubricants, and fillers in the above-mentioned film with resin materials as the main material. Like the first substrate 11, the second substrate 21 can also be treated on one or both sides of the second substrate 21 to improve the adhesion with the second adhesive layer 22 laminated on the surface of the second substrate 21 as desired. The thickness of the second substrate 21 is not particularly limited as long as the second adhesive sheet 20 can properly function in the desired step. The preferred thickness range of the second substrate 21 is the same as the thickness range described for the first substrate 11. In addition, the thickness of the first substrate 11 and the second substrate 21 may be the same or different.

・Second adhesive layer The second adhesive layer 22 is not particularly limited in terms of its constituent material as long as it can function appropriately in the desired step such as the cutting step. The second adhesive layer 22 may be composed of a non-energy ray-curing adhesive or an energy ray-curing adhesive. As the non-energy ray-curing adhesive, one having the desired adhesive force and re-peelability is preferred. Examples of the non-energy ray-curing adhesive include acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, polyester adhesives, and polyvinyl ether adhesives. Among these non-energy ray-curing adhesives, acrylic adhesives are preferred because they can effectively suppress the detachment of the workpiece (semiconductor wafer W) or the processed product (semiconductor chip CP) during the dicing step or the like.

On the other hand, since the adhesive force of the energy ray-curable adhesive is reduced by energy ray irradiation, when the workpiece or the processed object is to be separated from the second adhesive sheet 20, it can be easily separated by energy ray irradiation. The energy ray-curable adhesive constituting the second adhesive layer 22 may also be an adhesive containing a polymer having energy ray curability as a main component. In addition, the energy ray-curable adhesive constituting the second adhesive layer 22 may also be an adhesive containing a mixture of a polymer not having energy ray curability and at least one of an energy ray-curable multifunctional monomer and an energy ray-curable multifunctional oligomer as a main component. The case where the energy ray-curable adhesive contains a polymer having energy ray curability as a main component is described below.

・Energy ray curing polymer (A) The energy ray curing polymer is preferably a (meth)acrylate (co)polymer (A) (hereinafter sometimes referred to as "energy ray curing polymer (A)") having a functional group (energy ray curing group) having energy ray curing properties introduced into the side chain. The energy ray curing polymer (A) is preferably obtained by reacting a (meth)acrylic copolymer (a1) having a monomer unit containing a functional group and an unsaturated group-containing compound (a2) having a substituent bonded to the functional group. ・Acrylic copolymer (a1) The acrylic copolymer (a1) is composed of a constituent unit derived from a monomer containing a functional group and a constituent unit derived from a (meth)acrylate monomer or a derivative thereof. The functional group-containing monomer as a constituent unit of the acrylic copolymer (a1) is preferably a monomer having a polymerizable double bond and a functional group in the molecule. Examples of the functional group possessed by the functional group-containing monomer include a hydroxyl group, an amino group, a substituted amino group, and an epoxy group. As further specific examples of the above-mentioned functional group-containing monomer, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate are given. These functional group-containing monomers can be used alone or in combination of two or more.

As the (meth)acrylate monomer constituting the acrylic copolymer (a1), (meth)acrylate alkyl esters, (meth)acrylate cycloalkyl esters, and (meth)acrylate benzyl esters having an alkyl group with a carbon number of 1 to 20 are used. Among them, (meth)acrylate alkyl esters having an alkyl group with a carbon number of 1 to 18 are preferred, and examples thereof include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. The acrylic copolymer (a1) generally contains constituent units derived from the above-mentioned functional group-containing monomers at a ratio of 3 mass % to 100 mass %, preferably 5 mass % to 40 mass %, and generally contains constituent units derived from (meth)acrylate monomers or their derivatives at a ratio of 0 mass % to 97 mass %, preferably 60 mass % to 95 mass %. The acrylic copolymer (a1) is obtained by copolymerizing the above-mentioned functional group-containing monomers with (meth)acrylate monomers or their derivatives by a common method. In addition to the above-mentioned monomers, the acrylic copolymer (a1) may also be copolymerized with at least one monomer selected from the group consisting of dimethylacrylamide, vinyl formate, vinyl acetate and styrene. The acrylic copolymer (a1) having the above-mentioned functional group-containing monomer units is reacted with an unsaturated group-containing compound (a2) having a substituent bonded to the functional group to obtain an energy ray-curable polymer (A).

・Unsaturated group-containing compound (a2) The substituent of the unsaturated group-containing compound (a2) can be appropriately selected corresponding to the type of functional group of the functional group-containing monomer unit of the acrylic copolymer (a1). For example, when the functional group is a hydroxyl group, an amino group or a substituted amino group, the substituent is preferably an isocyanate group or an epoxy group, and when the functional group is an epoxy group, the substituent is preferably an amino group, a carboxyl group or an aziridine group. In addition, the unsaturated group-containing compound (a2) contains 1 or more and 5 or less, preferably 1 or more and 2 or less, energy-ray-polymerizable carbon-carbon double bonds per molecule. Specific examples of such unsaturated group-containing compounds (a2) include 2-methacryloyloxyethyl isocyanate, m-isopropenyl-α,α-dimethylbenzyl isocyanate, methacryloyl isocyanate, allyl isocyanate, 1,1-(diacryloyloxymethyl)ethyl isocyanate; acrylates obtained by reacting a diisocyanate compound or a polyisocyanate compound with hydroxyethyl (meth)acrylate; Acryloyl monoisocyanate compounds; acryl monoisocyanate compounds obtained by reacting a diisocyanate compound or a polyisocyanate compound with a polyol compound or hydroxyethyl (meth)acrylate; glycidyl (meth)acrylate; (meth)acrylic acid, 2-(1-aziridinyl)ethyl (meth)acrylate, 2-vinyl-2-oxazoline, 2-isopropenyl-2-oxazoline, etc.

The unsaturated group-containing compound (a2) is preferably used in a ratio of 10 mol% to 100 mol%, preferably 20 mol% to 95 mol%, relative to the functional group-containing monomer of the acrylic copolymer (a1). In the reaction between the acrylic copolymer (a1) and the unsaturated group-containing compound (a2), the reaction conditions such as reaction temperature, pressure, solvent, time, presence or absence of a catalyst, and type of catalyst can be appropriately selected according to the combination of functional groups and substituents. By appropriately selecting these reaction conditions, the functional groups present in the acrylic copolymer (a1) react with the substituents in the unsaturated group-containing compound (a2), and unsaturated groups are introduced into the side chains of the acrylic copolymer (a1), thereby obtaining an energy ray-curable polymer (A). The weight average molecular weight of the energy ray curable polymer (A) obtained in this way is preferably 10,000 or more, more preferably 150,000 or more and 1,500,000 or less, and even more preferably 200,000 or more and 1,000,000 or less. The weight average molecular weight (Mw) in this specification is a value measured by gel permeation chromatography (GPC) in terms of polystyrene.

・Energy ray-curable monomer and/or oligomer (B) When the energy ray-curable adhesive contains a polymer having energy ray-curability as a main component, the energy ray-curable adhesive may further contain an energy ray-curable monomer and/or oligomer (B). As the energy ray-curable monomer and/or oligomer (B), for example, esters of polyol and (meth) acrylic acid can be used. Examples of energy-ray-curable monomers and/or oligomers (B) include monofunctional acrylates such as cyclohexyl (meth)acrylate and isobornyl (meth)acrylate, trihydroxymethylpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, dihydroxymethyltricyclodecane di(meth)acrylate, polyester oligo(meth)acrylate, polyurethane oligo(meth)acrylate, etc. When the energy ray-curable monomer and/or oligomer (B) is formulated, the content of the energy ray-curable monomer and/or oligomer (B) in the energy ray-curable adhesive is preferably 5 mass % to 80 mass %, more preferably 20 mass % to 60 mass %.

・Photopolymerization initiator (C) Here, when ultraviolet rays are used as energy rays for curing the energy-ray-curable resin composition, it is preferable to add a photopolymerization initiator (C). By using the photopolymerization initiator (C), the polymerization curing time and the light irradiation amount can be reduced. Specific examples of the photopolymerization initiator (C) include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin benzoic acid methyl ester, benzoin dimethyl acetal, 2,4-diethylthioxanone, 1-hydroxycyclohexyl phenyl ketone, benzyl diphenyl sulfide, tetramethylthiuram monosulfide, azobenzene, Bisisobutyronitrile, biphenyl acyl, diphenyl acyl, diacetyl, β-chloroanthraquinone, (2,4,6-trimethylbenzyldiphenyl)phosphine oxide, 2-benzothiazole-N,N-diethyldithiocarbamate, oligo {2-hydroxy-2-methyl-1-[4-(1-propenyl)phenyl]acetone}, 2,2-dimethoxy-1,2-diphenylethane-1-one. These photopolymerization initiators (C) may be used alone or in combination of two or more. The photopolymerization initiator (C) is preferably used in an amount of 0.1 to 10 parts by mass, and more preferably in an amount of 0.5 to 6 parts by mass, relative to 100 parts by mass of the energy ray-curable copolymer (A) (when the energy ray-curable monomer and/or oligomer (B) is formulated, the total amount of the energy ray-curable copolymer (A and the formulated energy ray-curable monomer and/or oligomer (B) is 100 parts by mass).

In addition to the above-mentioned components, other components may be appropriately formulated in the energy ray-curable adhesive. Examples of other components include polymer components or oligomer components (D) that do not have energy ray curability, crosslinking agents (E), etc. Examples of polymer components or oligomer components (D) that do not have energy ray curability include polyacrylates, polyesters, polyurethanes, polycarbonates, polyolefins, etc., preferably polymers or oligomers with a weight average molecular weight (Mw) of 3,000 to 2,500,000.

・Crosslinking agent (E) As the crosslinking agent (E), a multifunctional compound that is reactive with the functional group of the energy ray-curable copolymer (A) can be used. Examples of such multifunctional compounds include isocyanate compounds, epoxy compounds, amine compounds, melamine compounds, aziridine compounds, hydrazine compounds, aldehyde compounds, oxazoline compounds, metal alkoxide compounds, metal chelate compounds, metal salts, ammonium salts, and reactive phenolic resins. By adding these other components (D) and (E) to the energy ray-curable adhesive, the adhesion and releasability before curing, the strength after curing, the adhesion to other layers, or the storage stability can be improved. The amount of the other components is not particularly limited, and can be appropriately determined within the range of 0 to 40 parts by mass based on 100 parts by mass of the energy ray-curable copolymer (A).

Next, the case where the energy ray-curable adhesive has a mixture of a polymer component that does not have energy ray curability and a multifunctional monomer and/or oligomer that has energy ray curability as the main component is described below. As the polymer component that does not have energy ray curability, the same component as the aforementioned acrylic copolymer (a1) can be used. The content of the polymer component that does not have energy ray curability in the energy ray-curable resin composition is preferably 20 mass % or more and 99.9 mass % or less, and more preferably 30 mass % or more and 80 mass % or less. As the multifunctional monomer and/or oligomer that has energy ray curability, the same one as the aforementioned component (B) is selected. The mixing ratio of the polymer component without energy ray curability to the multifunctional monomer and/or oligomer with energy ray curability is preferably 10 to 150 parts by mass of the multifunctional monomer and/or oligomer relative to 100 parts by mass of the polymer component, and more preferably 25 to 100 parts by mass. In this case, the photopolymerization initiator (C) or the crosslinking agent (E) can be appropriately mixed as described above. The thickness of the second adhesive layer 22 is not particularly limited as long as it can play an appropriate role in each step of using the second adhesive sheet 20. The thickness of the second adhesive layer 22 is preferably 1 μm to 50 μm, more preferably 2 μm to 30 μm, and even more preferably 3 μm to 20 μm. The above is the description about the second adhesive layer 22.

・Peeling sheet Before the second adhesive sheet 20 is used, it is preferable to stick a peeling sheet on the second adhesive layer 22 to protect the second adhesive layer 22. The peeling sheet may be directly laminated on the second adhesive layer 22, or another layer (die bonding film, etc.) may be laminated on the second adhesive layer 22, and the peeling sheet may be laminated on the other layer. The structure of the peeling sheet is arbitrary, and an example is a plastic film that is peeled by a peeling agent, etc. Examples of plastic films include polyester films such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polyolefin films such as polypropylene or polyethylene. Silicone, fluorine, and long-chain alkyl can be used as stripping agents. Among these stripping agents, silicone is preferred because it is cheap and has stable performance. The thickness of the stripping sheet is not particularly limited, but is usually about 20 μm to 250 μm. The thickness of the second adhesive sheet 20 is preferably 10 μm or more, and more preferably 30 μm or more. The thickness of the second adhesive sheet 20 is preferably 500 μm or less, and more preferably 300 μm or less.

(Third adhesive sheet) The third adhesive sheet 30 has a third substrate 31 and a third adhesive layer 32. The third adhesive layer 32 is laminated on the third substrate 31. ・Third substrate The third substrate 31 is not particularly limited in terms of its constituent material as long as it performs an appropriate function in the desired step such as the expansion step. The third substrate 31 has a first substrate surface and a second substrate surface opposite to the first substrate surface. In the third adhesive sheet 30, the third adhesive layer 32 is preferably provided on one of the first substrate surface and the second substrate surface, and the adhesive layer is preferably not provided on the other surface. From the viewpoint of easy large-scale extension, the material of the third substrate 31 is preferably a thermoplastic elastomer or a rubber-based material, and more preferably a thermoplastic elastomer. In addition, from the viewpoint of being easy to extend greatly, a resin with a relatively low glass transition temperature (Tg) is preferably used as the material of the third substrate 31. The glass transition temperature (Tg) of such resin is preferably 90°C or less, more preferably 80°C or less, and even more preferably 70°C or less.

Examples of thermoplastic elastomers include urethane elastomers, olefin elastomers, vinyl chloride elastomers, polyester elastomers, styrene elastomers, acrylic elastomers, and amide elastomers. Thermoplastic elastomers can be used alone or in combination of two or more. As a thermoplastic elastomer, urethane elastomers are preferably used from the viewpoint of being easily extended to a large extent. Urethane elastomers are generally obtained by reacting long-chain polyols, chain extenders, and diisocyanates. Urethane elastomers are composed of soft segments and hard segments, wherein the soft segments have constituent units derived from long-chain polyols, and the hard segments have a polyurethane structure obtained by the reaction of a chain extender and a diisocyanate. Urethane elastomers are classified into polyester polyurethane elastomers, polyether polyurethane elastomers, and polycarbonate polyurethane elastomers, etc., according to the type of long-chain polyols. Urethane elastomers can be used alone or in combination of two or more. In this embodiment, the urethane elastomer is preferably a polyether polyurethane elastomer from the viewpoint of easy and large extension. Examples of long-chain polyols include polyester polyols such as lactone polyester polyols and adipate polyester polyols; polyether polyols such as polypropylene (ethylene) polyols and polytetramethylene ether glycol; polycarbonate polyols, etc. In this embodiment, the long-chain polyol is preferably an adipate polyester polyol from the viewpoint of easy extension.

Examples of diisocyanates include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, and hexamethylene diisocyanate. In this embodiment, hexamethylene diisocyanate is preferred as the diisocyanate because it is easy to extend the chain. Examples of chain extenders include low molecular weight polyols (e.g., 1,4-butanediol and 1,6-hexanediol) and aromatic diamines. Among them, 1,6-hexanediol is preferred because it is easy to extend the chain. Examples of the olefinic elastomer include an elastomer containing at least one resin selected from the group consisting of ethylene-α-olefin copolymers, propylene-α-olefin copolymers, butene-α-olefin copolymers, ethylene-propylene-α-olefin copolymers, ethylene-butene-α-olefin copolymers, propylene-butene-α-olefin copolymers, ethylene-propylene-butene-α-olefin copolymers, styrene-isoprene copolymers, and styrene-ethylene-butene copolymers. The olefinic elastomer may be used alone or in combination of two or more.

The density of the olefinic elastomer is not particularly limited. For example, the density of the olefinic elastomer is preferably 0.860 g/cm ³ or more and less than 0.905 g/cm ³ , more preferably 0.862 g/cm ³ or more and less than 0.900 g/cm ³ , and particularly preferably 0.864 g/cm ³ or more and less than 0.895 g/cm ^3. When the density of the olefinic elastomer satisfies the above range, the substrate has excellent unevenness tracking properties when a semiconductor device such as a semiconductor wafer as an adherend is attached to an adhesive sheet. The mass ratio of monomers composed of olefinic compounds in all monomers used to form the olefinic elastomer (also referred to as "olefin content" in this specification) is preferably 50 mass% or more and 100 mass% or less. When the olefin content is too low, the properties of the elastomer containing structural units derived from olefins are difficult to show, and the substrate is difficult to show flexibility and rubber elasticity. From the viewpoint of stably obtaining flexibility and rubber elasticity, the olefin content is preferably 50 mass% or more, and more preferably 60 mass% or more.

Examples of styrene-based elastomers include styrene-copolymers and styrene-olefin copolymers. Specific examples of styrene-copolymers include unhydrogenated styrene-copolymers such as styrene-butadiene copolymers, styrene-butadiene-styrene copolymers (SBS), styrene-butadiene-butylene-styrene copolymers, styrene-isoprene copolymers, styrene-isoprene-styrene copolymers (SIS), styrene-ethylene-isoprene-styrene copolymers, and hydrogenated styrene-copolymers such as styrene-ethylene/propylene-styrene copolymers (SEPS, hydrogenated styrene-isoprene-styrene copolymers) and styrene-ethylene-butylene-styrene copolymers (SEBS, hydrogenated styrene-butadiene copolymers). In industry, examples of styrene-based elastomers include Tufprene (manufactured by Asahi Kasei Co., Ltd.), Clayton (manufactured by Japan Clayton Polymer Co., Ltd.), Sumitomo TPE-SB (manufactured by Sumitomo Chemical Co., Ltd.), Epofriend (manufactured by DAICEL Co., Ltd.), Rabaron (manufactured by Mitsubishi Chemical Co., Ltd.), Septon (manufactured by Kuraray Co., Ltd.), and Tuftec (manufactured by Asahi Kasei Co., Ltd.). Styrene-based elastomers may be hydrogenated or unhydrogenated. Examples of rubber materials include natural rubber, synthetic isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), chloroprene rubber (CR), acrylonitrile-butadiene copolymer rubber (NBR), butyl rubber (IIR), halogenated butyl rubber, acrylic rubber, urethane rubber, and polysulfide rubber. These rubber materials may be used alone or in combination of two or more.

The third substrate 31 is preferably a film formed of the above-mentioned material (such as a thermoplastic elastomer or a rubber-based material) rather than a laminated film formed of multiple layers, but a single-layer film. In addition, the third substrate 31 is also preferably a film formed of the above-mentioned material (such as a thermoplastic elastomer or a rubber-based material) rather than a laminated film formed by laminating with other films, but a single-layer film. The third substrate 31 may also contain additives in the film with the above-mentioned resin-based material as the main material. Specific examples of additives are the same as the additives described in the first substrate 11 and the second substrate 21. The content of the additive that can be contained in the film is not particularly limited, but it is preferably limited to the range in which the third substrate 31 can exert the desired function. The third substrate 31 , like the first substrate 11 and the second substrate 21 , may be subjected to treatment on one or both sides of the third substrate 31 to improve adhesion with the third adhesive layer 32 laminated on the surface of the third substrate 31 .

When the third adhesive layer 32 contains an energy ray-hardening adhesive, the third substrate 31 is preferably transparent to the energy ray. When ultraviolet rays are used as energy rays, the third substrate 31 is preferably transparent to ultraviolet rays. When electron beams are used as energy rays, the third substrate 31 is preferably transparent to electron beams. The thickness of the third substrate 31 is not particularly limited as long as the third adhesive sheet 30 can function properly in the desired step. The thickness of the third substrate 31 is preferably 20 μm or more, and more preferably 40 μm or more. In addition, the thickness of the third substrate 31 is preferably 250 μm or less, and more preferably 200 μm or less. Furthermore, the standard deviation of the thickness of the third substrate 31 when measuring the thickness of multiple locations at intervals of 2 cm on the first substrate surface or the second substrate surface of the third substrate 31 is preferably 2 μm or less, more preferably 1.5 μm or less, and even more preferably 1 μm or less. By making the standard deviation 2 μm or less, the third adhesive sheet 30 has a highly accurate thickness, and the third adhesive sheet 30 can be uniformly extended. The tensile elastic modulus in the MD direction and CD direction of the third substrate 31 at 23°C is 10 MPa or more and 350 MPa or less, respectively, and the 100% stress in the MD direction and CD direction of the third substrate 31 at 23°C is preferably 3 MPa or more and 20 MPa or less, respectively. By making the tensile elastic modulus and 100% stress within the above range, the third adhesive sheet 30 can be greatly extended.

The 100% stress of the third substrate 31 is a value obtained as follows. A test piece of 150 mm (in the length direction) × 15 mm (in the width direction) is cut out from the third substrate 31. The two ends of the cut test piece in the length direction are pinched by a pinching clamp in such a way that the length between the pinching clamps becomes 100 mm. After pinching the test piece with the pinching clamp, it is stretched in the length direction at a speed of 200 mm/min, and the tensile force measurement value when the length between the pinching clamps becomes 200 mm is read. The 100% stress of the third substrate 31 is a value obtained by dividing the read tensile force measurement value by the cross-sectional area of the substrate. The cross-sectional area of the third substrate 31 is calculated as 15 mm in the width direction × the thickness of the third substrate 31 (test piece). The cutting is performed in a manner that the direction of travel (MD direction) or the direction orthogonal to the MD direction (CD direction) when the substrate is manufactured is consistent with the length direction of the test piece. In addition, in the tensile test, the thickness of the test piece is not particularly limited and can be the same as the thickness of the substrate to be tested. The elongation at break of the third substrate 31 in the MD direction and the CD direction at 23°C is preferably 100% or more, respectively. By making the elongation at break of the third substrate 31 in the MD direction and the CD direction 100% or more, respectively, without causing rupture, the third adhesive sheet 30 can be greatly extended.

The tensile modulus of elasticity (MPa) of the substrate and the elongation at break (%) of the substrate can be measured as follows. The substrate is cut into 15mm×140mm to obtain a test piece. For the test piece, the elongation at break and the tensile modulus at 23°C are measured in accordance with JIS K7161:2014 and JIS K7127:1999. Specifically, the above-mentioned test piece is subjected to a tensile test at a speed of 200mm/min after the distance between the clamps is set to 100mm, and the elongation at break (%) and the tensile modulus (MPa) are measured. In addition, the measurement is performed in both the traveling direction (MD) when the substrate is manufactured and the direction perpendicular to it (CD).

・Third adhesive layer The constituent material of the third adhesive layer 32 is not particularly limited as long as it can play an appropriate role in the desired step such as the expansion step. Examples of the adhesive contained in the third adhesive layer 32 include rubber adhesives, acrylic adhesives, silicone adhesives, polyester adhesives, and urethane adhesives.

・Energy ray curing resin (ax1) The third adhesive layer 32 preferably contains an energy ray curing resin (ax1). The energy ray curing resin (ax1) has an energy ray curing double bond in the molecule. The adhesive layer containing the energy ray curing resin is cured by energy ray irradiation and the adhesive force is reduced. When the adherend and the adhesive sheet are to be separated, they can be easily separated by irradiating the adhesive layer with energy rays. The energy ray curing resin (ax1) is preferably a (meth) acrylic resin. The energy ray curing resin (ax1) is preferably a UV curing resin, and more preferably a UV curing (meth) acrylic resin. The energy ray curing resin (ax1) is a resin that polymerizes and cures when irradiated with energy rays. Examples of energy rays include ultraviolet rays and electron beams. Examples of energy ray-curable resins (ax1) include low molecular weight compounds (monofunctional monomers, polyfunctional monomers, monofunctional oligomers, and polyfunctional oligomers) having energy ray-polymerizable groups. Specifically, the energy ray curing resin (ax1) uses acrylates such as trihydroxymethylpropane triacrylate, tetrahydroxymethylmethane tetraacrylate, pentaerythritol triacrylate, dipentaerythritol monohydroxy pentaacrylate, dipentaerythritol hexaacrylate, 1,4-butanediol diacrylate, and 1,6-hexanediol diacrylate, acrylates containing a cyclic aliphatic skeleton such as dicyclopentadiene dimethoxy diacrylate and isobornyl acrylate, and acrylate compounds such as polyethylene glycol diacrylate, oligoester acrylate, urethane acrylate oligomer, epoxy modified acrylate, polyether acrylate, and itaconic acid oligomer. The energy ray curing resin (ax1) can be used alone or in combination of two or more. The molecular weight of the energy ray-curable resin (ax1) is usually in the range of 100 to 30,000, preferably in the range of 300 to 10,000.

・(Meth)acrylic copolymer (b1) The adhesive layer (third adhesive layer 32) of this embodiment preferably further contains a (meth)acrylic copolymer (b1). The (meth)acrylic copolymer is different from the aforementioned energy ray-curable resin (ax1). The (meth)acrylic copolymer (b1) preferably has a carbon-carbon double bond that is energy ray-curable. That is, in this embodiment, the adhesive layer (third adhesive layer 32) preferably contains an energy ray-curable resin (ax1) and an energy ray-curable (meth)acrylic copolymer (b1). The adhesive layer (third adhesive layer 32) of the present embodiment preferably contains the energy ray curable resin (ax1) in a ratio of 10 parts by mass or more, more preferably 20 parts by mass or more, and more preferably 25 parts by mass or more relative to 100 parts by mass of the (meth) acrylic copolymer (b1). The adhesive layer (third adhesive layer 32) of the present embodiment preferably contains the energy ray curable resin (ax1) in a ratio of 80 parts by mass or less, more preferably 70 parts by mass or less, and more preferably 60 parts by mass or less relative to 100 parts by mass of the (meth) acrylic copolymer (b1).

The weight average molecular weight (Mw) of the (meth)acrylic copolymer (b1) is preferably 10,000 or more, more preferably 150,000 or more, and even more preferably 200,000 or more. Moreover, the weight average molecular weight (Mw) of the (meth)acrylic copolymer (b1) is preferably 1.5 million or less, and more preferably 1 million or less. Moreover, the weight average molecular weight (Mw) in this specification is a value converted to standard polystyrene measured by gel permeation chromatography (GPC method). The (meth)acrylic copolymer (b1) is preferably a (meth)acrylate copolymer (b2) (hereinafter sometimes referred to as "energy ray-curable polymer (b2)") having a functional group (energy ray-curable group) having energy ray-curable properties introduced into the side chain.

・Energy ray-curable polymer (b2) The energy ray-curable polymer (b2) is preferably a copolymer obtained by reacting an acrylic copolymer (b21) having a monomer unit containing a functional group and an unsaturated group-containing compound (b22) having a functional group bonded to the functional group. In this specification, the so-called (meth)acrylate means both acrylate and methacrylate. Other similar terms are the same. The acrylic copolymer (b21) preferably contains a constituent unit derived from a monomer containing a functional group and a constituent unit derived from a (meth)acrylate monomer or a derivative of a (meth)acrylate monomer. The functional group-containing monomer as a constituent unit of the acrylic copolymer (b21) is preferably a monomer having a polymerizable double bond and a functional group in the molecule. The functional group is preferably at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, a substituted amino group, and an epoxy group.

Examples of monomers containing a hydroxyl group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. The monomers containing a hydroxyl group may be used alone or in combination of two or more. Examples of monomers containing a carboxyl group include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citric acid. The monomers containing a carboxyl group may be used alone or in combination of two or more. Examples of monomers containing an amino group or a substituted amino group include aminoethyl (meth)acrylate and n-butylaminoethyl (meth)acrylate. The amino group-containing monomer or the substituted amino group-containing monomer may be used alone or in combination of two or more.

As the (meth)acrylate monomer constituting the acrylic copolymer (b21), in addition to the (meth)acrylate alkyl ester having an alkyl group with a carbon number of 1 to 20, it is preferred to use a monomer having an alicyclic structure in the molecule (including alicyclic structure). As the (meth)acrylate alkyl ester, it is preferred to use the (meth)acrylate alkyl ester having an alkyl group with a carbon number of 1 to 18. Examples of the (meth)acrylate alkyl ester include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate and 2-ethylhexyl (meth)acrylate. As the (meth)acrylate alkyl ester, one kind alone or two or more kinds in combination can be used. Preferred monomers containing an alicyclic structure include, for example, cyclohexyl (meth)acrylate, dicyclopentyl (meth)acrylate, admanyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, and dicyclopentenyloxyethyl (meth)acrylate. The monomer containing an alicyclic structure may be used alone or in combination of two or more.

The acrylic copolymer (b21) preferably contains the constituent units derived from the above-mentioned functional group-containing monomer at a ratio of 1% by mass or more, more preferably 5% by mass or more, and more preferably 10% by mass or more. Furthermore, the acrylic copolymer (b21) preferably contains the constituent units derived from the above-mentioned functional group-containing monomer at a ratio of 35% by mass or less, more preferably 30% by mass or less, and more preferably 25% by mass or less. Furthermore, the acrylic copolymer (b21) preferably contains the constituent units derived from the (meth)acrylate monomer or its derivative at a ratio of 50% by mass or more, more preferably 60% by mass or more, and more preferably 70% by mass or more. Furthermore, the acrylic copolymer (b21) preferably contains constituent units derived from a (meth)acrylate monomer or a derivative thereof in an amount of 99 mass % or less, more preferably 95 mass % or less, and even more preferably 90 mass % or less.

The acrylic copolymer (b21) is obtained by copolymerizing the functional group-containing monomer as described above with a (meth)acrylate monomer or a derivative thereof by a conventional method. In addition to the above monomers, the acrylic copolymer (b21) may also contain a constituent unit of at least one selected from the group consisting of dimethylacrylamide, vinyl formate, vinyl acetate and styrene. The acrylic copolymer (b21) having the above functional group-containing monomer unit is reacted with an unsaturated group-containing compound (b22) having a functional group bonded to the functional group to obtain an energy ray-curable polymer (b2). The functional group of the unsaturated group-containing compound (b22) can be appropriately selected corresponding to the type of functional group of the functional group-containing monomer unit of the acrylic copolymer (b21). For example, when the functional group of the acrylic copolymer (b21) is a hydroxyl group, an amino group or a substituted amino group, the functional group of the unsaturated group-containing compound (b22) is preferably an isocyanate group or an epoxy group. When the functional group of the acrylic copolymer (b21) is an epoxy group, the functional group of the unsaturated group-containing compound (b22) is preferably an amino group, a carboxyl group or an aziridine group.

The unsaturated group-containing compound (b22) contains at least one, preferably one or more and six or less, and more preferably one or more and four or less, energy-ray-polymerizable carbon-carbon double bonds in one molecule. Examples of the unsaturated group-containing compound (b22) include 2-methacryloyloxyethyl isocyanate (2-isocyanatoethyl methacrylate), m-isopropenyl-α,α-dimethylbenzyl isocyanate, methacryloyl isocyanate, allyl isocyanate, 1,1-(diacryloyloxymethyl)ethyl isocyanate; a reaction product of a diisocyanate compound or a polyisocyanate compound with hydroxyethyl (meth)acrylate. The acryl monoisocyanate compound thus obtained; an acryl monoisocyanate compound obtained by reacting a diisocyanate compound or a polyisocyanate compound with a polyol compound or hydroxyethyl (meth)acrylate; glycidyl (meth)acrylate; (meth)acrylic acid, 2-(1-aziridinyl)ethyl (meth)acrylate, 2-vinyl-2-oxazoline, 2-isopropenyl-2-oxazoline, etc.

The unsaturated group-containing compound (b22) is preferably used at a ratio (addition rate) of 50 mol% or more relative to the molar number of the functional group-containing monomer of the acrylic copolymer (b21), more preferably at a ratio of 60 mol% or more, and more preferably at a ratio of 70 mol% or more. And the unsaturated group-containing compound (b22) is preferably used at a ratio of 95 mol% or less relative to the molar number of the functional group-containing monomer of the acrylic copolymer (b21), more preferably at a ratio of 93 mol% or less, and more preferably at a ratio of 90 mol% or less. In the reaction between the acrylic copolymer (b21) and the unsaturated group-containing compound (b22), the reaction temperature, pressure, solvent, time, presence or absence of a catalyst, and the type of catalyst can be appropriately selected according to the combination of the functional groups of the acrylic copolymer (b21) and the unsaturated group-containing compound (b22). In this way, the functional groups of the acrylic copolymer (b21) and the unsaturated group-containing compound (b22) react, and the unsaturated group is introduced into the side chain of the acrylic copolymer (b21) to obtain the energy ray-curable polymer (b2). The weight average molecular weight (Mw) of the energy ray-curable polymer (b2) is preferably 10,000 or more, more preferably 150,000 or more, and even more preferably 200,000 or more. Furthermore, the weight average molecular weight (Mw) of the energy ray-curable polymer (b2) is preferably 1.5 million or less, and more preferably 1 million or less.

・Photopolymerization initiator (CX) When the adhesive layer (third adhesive layer 32) contains a UV-curable compound (e.g., UV-curable resin), the adhesive layer (third adhesive layer 32) preferably contains a photopolymerization initiator (CX). By making the adhesive layer (third adhesive layer 32) contain a photopolymerization initiator (CX), the polymerization curing time and the amount of light irradiation can be reduced. The specific example of the photopolymerization initiator (CX) is the same as the specific example of the photopolymerization initiator (C) in the description of the second adhesive sheet 20. The photopolymerization initiator (CX) in the third adhesive sheet 30 may be used alone or in combination of two or more. When the energy ray curable resin (ax1) and the (meth) acrylic copolymer (b1) are prepared in the adhesive layer (third adhesive layer 32), the photopolymerization initiator (CX) is preferably used in an amount of 0.1 parts by mass or more, and more preferably in an amount of 0.5 parts by mass or more, relative to 100 parts by mass of the total amount of the energy ray curable resin (ax1) and the (meth) acrylic copolymer (b1). Furthermore, when the energy ray curable resin (ax1) and the (meth) acrylic copolymer (b1) are mixed in the adhesive layer (the third adhesive layer 32), the photopolymerization initiator (CX) is preferably used in an amount of 10 parts by mass or less, and more preferably in an amount of 6 parts by mass or less, relative to 100 parts by mass of the total amount of the energy ray curable resin (ax1) and the (meth) acrylic copolymer (b1). In addition to the above-mentioned components, other suitable components may also be mixed in the adhesive layer (the third adhesive layer 32). Examples of other components include a crosslinking agent (EX).

・Crosslinking agent (EX) As the crosslinking agent (EX), a polyfunctional compound reactive with the functional group of the (meth)acrylic copolymer (b1) or the like can be used. The examples of the polyfunctional compound in the third adhesive sheet 30 are the same as the specific examples of the polyfunctional compound as the crosslinking agent (E) in the description of the second adhesive sheet 20. The amount of the crosslinking agent (EX) is preferably 0.01 parts by mass or more, more preferably 0.03 parts by mass or more, and even more preferably 0.04 parts by mass or more, relative to 100 parts by mass of the (meth)acrylic copolymer (b1). The amount of the crosslinking agent (EX) to be added is preferably 8 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 3.5 parts by mass or less, based on 100 parts by mass of the (meth)acrylic copolymer (b1).

The thickness of the adhesive layer (the third adhesive layer 32) is not particularly limited. The thickness of the adhesive layer (the third adhesive layer 32) is preferably 10 μm or more, and more preferably 20 μm or more. Furthermore, the thickness of the adhesive layer (the third adhesive layer 32) is preferably 150 μm or less, and more preferably 100 μm or less. The recovery rate of the third adhesive sheet 30 is preferably 70% or more, more preferably 80% or more, and more preferably 85% or more. The recovery rate of the third adhesive sheet 30 is preferably 100% or less. If the recovery rate is within the above range, the adhesive sheet can be greatly extended. The recovery rate is the recovery rate of the adhesive sheet cut out of 150 mm. A test piece of 15 mm (length) × 15 mm (width) was pinched at both ends of the length direction with a pinching clamp so that the length between the pinching clamps was 100 mm. The length between the pinching clamps was then stretched to 200 mm at a speed of 200 mm/min. The length between the pinching clamps was maintained at 200 mm for 1 minute. The length between the pinching clamps was then restored to 100 mm at a speed of 200 mm/min. After the length is restored to 100mm, it is maintained for 1 minute, and then stretched in the longitudinal direction at a speed of 60mm/min. The length between the pinching tools when the measured value of the tensile force shows 0.1N/15mm is measured. The length of the initial length between the pinching tools of 100mm is subtracted from the length is set as L2 (mm). The length of the initial length between the pinching tools of 200mm in the above-mentioned expanded state minus the initial length between the pinching tools of 100mm is set as L1 (mm), and the following formula (number 2) is used to calculate. Recovery rate (%) = {1-(L2÷L1)}×100    …(number 2)

When the recovery rate is within the above range, it means that the adhesive sheet can be easily restored even after being greatly stretched. Generally, if a sheet with a yield point is extended above the yield point, the sheet will cause plastic deformation, and the part that causes plastic deformation, that is, the extremely extended part, will become a localized state. If the sheet in this state is further extended, a fracture will occur from the above-mentioned extremely extended part, or even if a fracture does not occur, the expansion will be uneven. Moreover, in the stress-strain graph that plots the deformation as the x-axis and the elongation as the y-axis, even if the slope dx/dy does not become a stress value that changes from a positive value to 0 or a negative value, and the sheet does not show a clear yield point, the sheet will cause plastic deformation as the amount of stretching increases, and will also cause fractures or uneven expansion. On the other hand, when elastic deformation occurs instead of plastic deformation, the sheet easily recovers to its original shape by removing the stress. Therefore, by setting the recovery rate, which is an indicator of the degree of recovery after 100% elongation with a sufficiently large stretching amount, to the above range, the plastic deformation of the film can be suppressed to a minimum when the adhesive sheet is stretched to a large extent, and it is difficult to cause fracture, and uniform expansion can be achieved.

・Peeling sheet The third adhesive sheet 30 may be laminated with a peeling sheet on the adhesive surface for the purpose of protecting the adhesive surface until the adhesive surface is attached to the adherend (e.g., a semiconductor chip). The structure of the peeling sheet is arbitrary, and an example is a peeling sheet of a plastic film treated with a peeling agent. The peeling sheet may be a peeling sheet that can be used for the first adhesive sheet 10 and the second adhesive sheet 20. The thickness of the third adhesive sheet 30 is not particularly limited, but is preferably 30 μm or more, and more preferably 50 μm or more. The thickness of the third adhesive sheet 30 is preferably 400 μm or less, and more preferably 300 μm or less.

[Effects of the present embodiment] According to the expansion method of the present embodiment, when the third adhesive sheet 30 is stretched, the electric surface W1 of the semiconductor chip CP does not contact the third adhesive layer 32 of the third adhesive sheet 30. In each of the semiconductor chips CP, since the electric surface W1 and the third adhesive layer 32 are separated by the first adhesive sheet 10 singulated in the dicing step, even if the third adhesive sheet 30 is stretched, the first adhesive layer 12 of the first adhesive sheet 10 in contact with the electric surface W1 is not stretched. As a result, according to the expansion method of the present embodiment, the residual slurry can be suppressed. In addition, the adhesive sheets used in the expansion method of the present embodiment are all simple structures consisting of a substrate and an adhesive layer. Furthermore, before the expansion step is performed, since the adhesive sheet used during the cutting step is replaced with the adhesive sheet used in the expansion step, it is not necessary to carefully control the cutting depth in the cutting step so that the cutting blade does not reach the substrate of the cutting sheet. Therefore, according to the expansion method of this embodiment, the adhesive sheet structure and process can be simplified compared with the past and the residual smear can be suppressed. Furthermore, a manufacturing method of a semiconductor device including the expansion method of this embodiment can be provided.

[Second embodiment] Next, the second embodiment of the present invention will be described. The first embodiment and the second embodiment differ mainly in the following aspects. In the first embodiment, the adhesive sheet adhered to the electrical path surface of the semiconductor wafer in the back grinding step and the cutting step is the same adhesive sheet. In contrast, in the second embodiment, the adhesive sheet adhered to the semiconductor wafer in the back grinding step and the adhesive sheet adhered to the electrical path surface of the semiconductor wafer in the cutting step are different. In the following description, the difference from the first embodiment will be mainly described, and the repeated description will be omitted or simplified. The same symbols are given to the same components as the first embodiment, and the description is omitted or simplified. The extended method of this embodiment includes steps (P1) to (P5) described in the first embodiment, and further includes step (PX1), step (PX2) and step (PX3). Steps (PX1), (PX2) and (PX3) are implemented before step (P1).

(PX1) Before the semiconductor wafer is back-grinded, the fourth adhesive sheet is attached to the first wafer surface. (PX2) The semiconductor wafer with the fourth adhesive sheet attached is back-grinded. (PX3) After the semiconductor wafer is back-grinded, the fourth adhesive sheet is peeled off from the first wafer surface and the first adhesive sheet is attached to the first wafer surface. [Back grinding step] Figure 6A is a diagram for explaining step (PX1) and step (PX2). In the back grinding step of this embodiment, the back surface W6 on the opposite side of the electrical path W1 is ground by a grinder 500 to grind the semiconductor wafer W to a specific thickness. The back surface W6 of the semiconductor wafer W is back-grinded to form a back surface W3. In the back grinding step of the present embodiment, the fourth adhesive sheet 40 is pasted on the electrical surface W1 of the semiconductor wafer W. The fourth adhesive sheet 40 has a fourth adhesive layer 42 and a fourth substrate 41. In the present embodiment, the fourth adhesive sheet 40 is preferably a back grinding sheet. When the fourth adhesive sheet 40 is used as a back grinding sheet, the semiconductor wafer W is pasted with the electrical surface W1 facing the fourth adhesive layer 42 of the fourth adhesive sheet 40. Before grinding the semiconductor wafer W from the back, it is preferred to paste the fourth adhesive sheet 40 as a back grinding sheet on the electrical surface W1 as the first wafer surface. The fourth adhesive sheet 40 is preferably the same adhesive sheet as the first adhesive sheet 10 in the first embodiment.

[Step of peeling off the fourth adhesive sheet and step of sticking the first adhesive sheet] Figure 6B is a diagram for explaining step (PX3). Figure 6B shows a state where the first adhesive sheet 70 is stuck on the surface W1 of the electrical circuit after the fourth adhesive sheet 40 is peeled off from the surface W1 of the electrical circuit after the back of the semiconductor wafer W is ground. In this embodiment, as described above, after the back grinding step, the next step is not performed in the state where the back grinding sheet (the fourth adhesive sheet 40) is stuck on the surface W1 of the electrical circuit, but another adhesive sheet (the first adhesive sheet 70) is stuck on the surface W1 of the electrical circuit. The first adhesive sheet 70 as the other adhesive sheet is preferably a surface protection sheet for protecting the surface W1 of the electrical circuit. In addition, the first adhesive sheet is used as a back grinding sheet in the first embodiment, but the first adhesive sheet in the present embodiment is used as a surface protection sheet, so the attachment position of the first adhesive sheet is different. Therefore, the symbol of the first adhesive sheet in the first embodiment is represented by 10, and the symbol of the first adhesive sheet in the present embodiment is represented by 70 for distinction. The thickness of the first adhesive sheet 70 as a surface protection sheet is preferably thinner than the thickness of the fourth adhesive sheet 40 as a back grinding sheet. By making the thickness of the first adhesive sheet 70 thinner than the thickness of the fourth adhesive sheet 40, the cutting of the first adhesive sheet 70 and the semiconductor wafer W is facilitated in the cutting step. The thickness of the first adhesive sheet 70 as a surface protection sheet is preferably 5 μm or more, more preferably 10 μm or more, and more preferably 30 μm or more. The thickness of the first adhesive sheet 70 as a surface protection sheet is preferably 500 μm or less, more preferably 300 μm or less, and more preferably 100 μm or less.

[Stick-on step of the second adhesive sheet] In this embodiment, as in the first embodiment, the semiconductor wafer W prepared in step (P1) is preferably a wafer obtained by a back grinding step and then a sticking step of sticking the second adhesive sheet 20 on the back surface W3. FIG. 7A shows a diagram illustrating the sticking step of sticking the second adhesive sheet 20 on the back surface W3. In this embodiment, as in the first embodiment, the second adhesive sheet 20 is preferably a dicing sheet. When the second adhesive sheet 20 is used as a dicing sheet, the semiconductor wafer W is stuck with the back surface W3 facing the second adhesive layer 22 of the second adhesive sheet 20.

[Cutting step] Figure 7B is a diagram for explaining step (P2) of this embodiment. Step (P2) is sometimes referred to as a cutting step. In Figure 7B, a plurality of semiconductor chips CP obtained by cutting the semiconductor wafer W are shown. Step (P2) of this embodiment is different from the first embodiment in that the first adhesive sheet 70 is pasted on the conductive surface W1, but other aspects can be implemented in the same manner as the first embodiment. In this embodiment, a cut is also made from the side of the first adhesive sheet 70 to cut the first adhesive sheet 70, and then the semiconductor wafer W is cut.

[Standing step of the third adhesive sheet] Figure 8A is a diagram for explaining step (P3). Step (P3) is sometimes referred to as the step of sticking the third adhesive sheet. Figure 8A shows a state where the third adhesive sheet 30 is stuck on the plurality of semiconductor chips CP obtained by the cutting step. The third adhesive sheet 30 is the same as that of the first embodiment. Step (P3) of this embodiment is different from the first embodiment in that the third adhesive sheet 30 is stuck on the first adhesive sheet 70 as a surface protection sheet. Other aspects can be implemented in the same way as the first embodiment.

[Step of peeling off the second adhesive sheet] Figure 8B is a diagram for explaining step (P4) of the present embodiment. Step (P4) is sometimes referred to as the step of peeling off the second adhesive sheet. Figure 8B shows the state of peeling off the second adhesive sheet 20 from the back surface W3 of the wafer W after the third adhesive sheet 30 is attached. Step (P4) of the present embodiment can be implemented in the same manner as the first embodiment.

[Expansion step] Figure 9 is a diagram for explaining step (P5) of the present embodiment. Step (P5) is sometimes referred to as the expansion step. Figure 9 shows a state where the third adhesive sheet 30 is stretched to expand the interval between the plurality of semiconductor chips CP after the second adhesive sheet 20 is peeled off. In the present embodiment, the third adhesive sheet 30 is preferably an expansion sheet. Step (P5) of the present embodiment can be implemented in the same manner as the first embodiment. In the present embodiment, the interval D1 between the plurality of semiconductor chips CP is also preferably the same as the first embodiment.

[Sealing step and other steps] In this embodiment, the sealing step and other steps (rewiring layer forming step and connection step with external terminal electrodes) can also be implemented in the same manner as in the first embodiment. (Fourth adhesive sheet) The fourth adhesive sheet 40 is preferably an adhesive sheet similar to the first adhesive sheet 10 described in the first embodiment. (First adhesive sheet) The first adhesive sheet 70 of this embodiment has a seventh substrate 71 and a seventh adhesive layer 72. The seventh adhesive layer 72 is laminated on the seventh substrate 71. ・Seventh substrate The seventh substrate 71 is a member that supports the seventh adhesive layer 72. The material of the seventh substrate 71 is not particularly limited as long as it can play an appropriate role in the desired step such as the cutting step. The thickness of the seventh substrate 71 is preferably 5 μm or more, more preferably 10 μm or more, and more preferably 15 μm or more. The thickness of the seventh substrate 71 is preferably 100 μm or less, more preferably 75 μm or less, and more preferably 50 μm or less.

As the seventh substrate 71, a sheet material such as a synthetic resin film can be used. Examples of synthetic resin films include polyethylene film, polypropylene film, polybutylene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate copolymer film, ionic polymer resin film, ethylene-(meth)acrylic acid copolymer film, ethylene-(meth)acrylic acid ester copolymer film, polystyrene film, polycarbonate film, and polyimide film. In addition, as the seventh substrate 71, examples include such crosslinked films and laminated films. The seventh substrate 71 preferably includes a polyester resin, and more preferably is composed of a material having a polyester resin as a main component. In this specification, the material having a polyester resin as a main component means that the mass ratio of the polyester resin in the total mass of the material constituting the base material is 50 mass% or more.

As the polyester resin, it is preferably any resin selected from the group consisting of polyethylene terephthalate resin, polybutylene terephthalate resin, polyethylene naphthalate resin, polybutylene naphthalate resin and copolymer resins of these resins, and polyethylene terephthalate resin is more preferred. As the seventh substrate 71, polyethylene terephthalate film and polyethylene naphthalate film are preferred, and polyethylene terephthalate film is more preferred. The oligomer contained in the polyester film is derived from polyester-forming monomers, dimers and trimers, etc.

・7th adhesive layer The material constituting the 7th adhesive layer 72 is not particularly limited as long as it can properly function in the desired step such as the cutting step. In the present embodiment, the 7th adhesive layer 72 is preferably composed of at least one adhesive selected from the group consisting of, for example, acrylic adhesives, urethane adhesives, polyester adhesives, rubber adhesives, and silicone adhesives, and is more preferably composed of acrylic adhesives. The 7th adhesive layer 72 of the present embodiment preferably includes an adhesive composition. The adhesive composition preferably includes an acrylic copolymer having 2-ethylhexyl acrylate as a main monomer. In this specification, "using 2-ethylhexyl acrylate as the main monomer" means that the mass ratio of the copolymer component derived from 2-ethylhexyl acrylate in the total mass of the acrylic copolymer is 50 mass% or more. In this embodiment, the ratio of the copolymer component derived from 2-ethylhexyl acrylate in the acrylic copolymer is preferably 50 mass% or more and 95 mass% or less, more preferably 60 mass% or more and 95 mass% or less, still more preferably 80 mass% or more and 95 mass% or less, and still more preferably 85 mass% or more and 93 mass% or less.

The type and number of copolymer components other than 2-ethylhexyl acrylate in the acrylic copolymer are not particularly limited. For example, as the second copolymer component, a functional group-containing monomer having a reactive functional group is preferred. As the reactive functional group of the second copolymer component, when using a crosslinking agent described later, it is preferably a functional group that can react with the crosslinking agent. The reactive functional group is preferably at least one substituent selected from the group consisting of, for example, carboxyl, hydroxyl, amino, substituted amino and epoxy groups, more preferably at least one substituent of carboxyl and hydroxyl groups, and more preferably carboxyl. Examples of monomers having a carboxyl group (monomers containing a carboxyl group) include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid and citric acid. Among the carboxyl-containing monomers, acrylic acid is preferred based on reactivity and copolymerizability. The carboxyl group-containing monomer may be used alone or in combination of two or more.

Examples of monomers having a hydroxyl group (monomers containing a hydroxyl group) include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Among the monomers containing a hydroxyl group, 2-hydroxyethyl (meth)acrylate is preferred in terms of the reactivity and copolymerizability of the hydroxyl group. Monomers containing a hydroxyl group may be used alone or in combination of two or more. Examples of acrylates having an epoxy group include glycidyl acrylate and glycidyl methacrylate. As other copolymer components in the acrylic copolymer, an alkyl (meth)acrylate having an alkyl group with 2 to 20 carbon atoms is exemplified. Examples of the alkyl (meth)acrylate include 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, myristyl (meth)acrylate, palmityl (meth)acrylate, and stearyl (meth)acrylate. Among these alkyl (meth)acrylates, an alkyl (meth)acrylate having an alkyl group with 2 to 4 carbon atoms is preferred, and n-butyl (meth)acrylate is more preferred, from the viewpoint of further improving adhesion. The alkyl (meth)acrylate may be used alone or in combination of two or more.

Examples of other copolymer components in the acrylic copolymer include copolymer components derived from at least one monomer selected from the group consisting of (meth)acrylates containing alkoxyalkyl groups, (meth)acrylates having aliphatic rings, (meth)acrylates having aromatic rings, non-crosslinking acrylamides, (meth)acrylates having non-crosslinking tertiary amine groups, vinyl acetate, and styrene. Examples of (meth)acrylates containing alkoxyalkyl groups include methoxymethyl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxymethyl (meth)acrylate, and ethoxyethyl (meth)acrylate. Examples of (meth)acrylates having aliphatic rings include cyclohexyl (meth)acrylate. Examples of (meth)acrylates having aromatic rings include phenyl (meth)acrylate. Examples of non-crosslinking acrylamides include acrylamide and methacrylamide. Examples of (meth)acrylates having non-crosslinking tertiary amine groups include (meth)acrylate (N,N-dimethylamino)ethyl and (meth)acrylate (N,N-dimethylamino)propyl. These monomers may be used alone or in combination of two or more.

In this embodiment, the second copolymer component is preferably a carboxyl-containing monomer or a hydroxyl-containing monomer, and more preferably acrylic acid. When the acrylic copolymer includes a copolymer component derived from 2-ethylhexyl acrylate and a copolymer component derived from acrylic acid, the mass ratio of the copolymer component derived from acrylic acid to the total mass of the acrylic copolymer is preferably 1 mass % or less, and more preferably 0.1 mass % or more and 0.5 mass % or less. If the proportion of acrylic acid is 1 mass % or less, when a crosslinking agent is included in the adhesive composition, the crosslinking of the acrylic copolymer can be prevented from proceeding too quickly. The acrylic copolymer may also include two or more copolymer components derived from functional group-containing monomers. For example, the acrylic copolymer may be a ternary copolymer, preferably an acrylic copolymer obtained by copolymerizing 2-ethylhexyl acrylate, a carboxyl-containing monomer and a hydroxyl-containing monomer, wherein the carboxyl-containing monomer is preferably acrylic acid, and the hydroxyl-containing monomer is preferably 2-hydroxyethyl acrylate. Preferably, the proportion of the copolymer component derived from 2-ethylhexyl acrylate in the acrylic copolymer is 80 mass % to 95 mass %, the mass proportion of the copolymer component derived from acrylic acid is 1 mass % or less, and the remainder is the copolymer component derived from 2-hydroxyethyl acrylate.

The weight average molecular weight (Mw) of the acrylic copolymer is preferably 300,000 to 2,000,000, more preferably 600,000 to 1,500,000, and even more preferably 800,000 to 1,200,000. If the weight average molecular weight Mw of the acrylic copolymer is 300,000 or more, it can be peeled off from the adherend without adhesive residue. If the weight average molecular weight Mw of the acrylic copolymer is 2,000,000 or less, it can be firmly attached to the adherend. The weight average molecular weight Mw of the acrylic copolymer is a value converted to standard polystyrene measured by gel permeation chromatography (GPC). The acrylic copolymer can be manufactured using the various raw material monomers mentioned above according to the conventional known method. The morphology of the acrylic copolymer is not particularly limited, and it can be any of a block copolymer, a random copolymer, or a graft copolymer.

In this embodiment, the content of the acrylic copolymer in the adhesive composition is preferably 40% by mass or more and 90% by mass or less, and more preferably 50% by mass or more and 90% by mass or less. The adhesive composition constituting the seventh adhesive layer 72 preferably includes at least an adhesive obtained by crosslinking a composition further blended with a crosslinking agent, in addition to the aforementioned acrylic copolymer. Moreover, the adhesive composition is preferably substantially composed of an adhesive obtained by crosslinking the aforementioned acrylic copolymer and a crosslinking agent. Here, substantially means that it is composed only of the adhesive, excluding trace impurities that are inevitably mixed in the adhesive. Examples of the crosslinking agent include isocyanate crosslinking agents, epoxy crosslinking agents, aziridine crosslinking agents, metal chelate crosslinking agents, amine crosslinking agents, and amino resin crosslinking agents. These crosslinking agents may be used alone or in combination of two or more.

From the viewpoint of improving the heat resistance and adhesion of the seventh adhesive layer 72, it is preferred that the crosslinking agents contain a compound having an isocyanate group as a main component (isocyanate-based crosslinking agent). Examples of isocyanate crosslinking agents include polyisocyanate compounds such as 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,3-xylene diisocyanate, 1,4-xylene diisocyanate, diphenylmethane-4,4'-diisocyanate, diphenylmethane-2,4'-diisocyanate, 3-methyldiphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, and lysine isocyanate. In addition, the polyisocyanate compound may be a trihydroxymethylpropane addition type modified product of the above-mentioned compound, a urea type modified product reacting with water, or an isocyanurate type modified product having an isocyanurate ring. In this specification, the crosslinking agent containing a compound having an isocyanate group as a main component means that the mass ratio of the compound having an isocyanate group to the total mass of the components constituting the crosslinking agent is 50% by mass or more.

In this embodiment, the content of the crosslinking agent in the adhesive composition is preferably 0.1 to 20 parts by mass, more preferably 1 to 15 parts by mass, and even more preferably 5 to 10 parts by mass, relative to 100 parts by mass of the acrylic copolymer. If the content of the crosslinking agent in the adhesive composition is within this range, the adhesion between the seventh adhesive layer 72 and the seventh substrate 71 can be improved, and the curing period for stabilizing the adhesive properties after the adhesive sheet is manufactured can be shortened. In the case where the adhesive composition constituting the seventh adhesive layer 72 in this embodiment includes a crosslinking agent, the adhesive composition preferably further includes a crosslinking accelerator. The crosslinking promoter is preferably selected and used appropriately according to the type of crosslinking agent. For example, when the adhesive composition includes a polyisocyanate compound as a crosslinking agent, it is preferred to further include a crosslinking promoter of an organic metal compound such as an organic tin compound. In addition, the adhesive composition constituting the seventh adhesive layer 72 also preferably includes a reactive adhesive aid. Examples of reactive adhesive aids include polybutadiene resins having reactive functional groups and hydrogenated products of polybutadiene resins having reactive functional groups. The reactive functional group of the reactive adhesive agent is preferably one or more functional groups selected from the group consisting of hydroxyl, isocyanate, amino, epoxy, anhydride, alkoxy, acryl and methacryl. When the adhesive composition contains the reactive adhesive agent, the residual adhesive when the first adhesive sheet 70 is peeled off from the adherend can be reduced.

In this embodiment, the adhesive composition constituting the seventh adhesive layer 72 may also contain other components within the scope that does not impair the effect of the present invention. Examples of other components that may be contained in the adhesive composition include organic solvents, flame retardants, adhesive imparting agents, ultraviolet absorbers, antioxidants, preservatives, mold inhibitors, plasticizers, defoaming agents, and wettability regulators. The thickness of the seventh adhesive layer 72 is appropriately determined corresponding to the purpose of the first adhesive sheet 70. In this embodiment, the thickness of the seventh adhesive layer 72 is preferably 5 μm or more. The thickness of the seventh adhesive layer 72 is preferably 60 μm or less, and more preferably 50 μm or less. The above is a description of the seventh adhesive layer 72. ・Peeling sheet During the period until the first adhesive sheet 70 is attached to the adherend (such as a semiconductor wafer W or a semiconductor chip CP, etc.), a peeling sheet may be laminated on the adhesive surface for the purpose of protecting the adhesive surface. The structure of the peeling sheet is arbitrary, and an example is a peeling sheet of a plastic film subjected to a peeling agent. The peeling sheet may also be a peeling sheet that can be used for the first adhesive sheet 10 and the second adhesive sheet 20.

[Effects of the present embodiment] According to the expansion method of the present embodiment, as in the first embodiment, the adhesive sheet structure and process can be simplified compared to the past and the residual smear can be suppressed. Furthermore, a method for manufacturing a semiconductor device including the expansion method of the present embodiment can be provided. In addition, in the expansion method of the present embodiment, after the back grinding step, before the cutting step, the first adhesive sheet 70 thinner than the fourth adhesive sheet 40 used in the back grinding step is replaced. Since the thickness of the adhesive sheet cut in the cutting step can be reduced, the load applied to the cutting blade can be reduced.

[Third Implementation] Next, the third implementation of the present invention will be described. The first implementation differs from the third implementation mainly in the following aspects. In the first implementation, the dicing step is performed after the back grinding step. In contrast, in the third implementation, a so-called pre-dicing method is performed. The pre-dicing method is a method of forming a groove of a specific depth from the surface side of a semiconductor wafer, grinding from the back side of the wafer, and removing the bottom of the groove by grinding to separate the wafer into pieces to obtain a chip. In the following description, the main difference from the first implementation is described, and the repeated description is omitted or simplified. The same symbols are given to the same components as the first implementation, and the description is omitted or simplified.

The expansion method of this embodiment includes the following steps (PY1) to (PY4) and the same step (P5) as the first embodiment. (PY1) A step of attaching the eighth adhesive sheet to the first wafer surface of the wafer before back grinding. (PY2) A step of forming a groove of a specific depth from the first wafer surface of the wafer. (PY3) A step of back grinding the second wafer surface of the wafer with the groove formed thereon to remove the bottom of the groove to obtain a chip. (PY4) A step of attaching the third adhesive sheet to the eighth adhesive sheet after back grinding of the wafer. (P5) A step of stretching the third adhesive sheet and expanding the interval between a plurality of chips.

[Stick-on step of the 8th adhesive sheet] Figure 10A is a diagram for explaining step (PY1). Figure 10A shows a state where the 8th adhesive sheet 80 is stuck to the electric surface W1 of the 1st wafer surface of the semiconductor wafer W before back grinding. The 8th adhesive sheet 80 has an 8th adhesive layer 82 and an 8th substrate 81. In this embodiment, the 8th adhesive sheet 80 is preferably a back grinding sheet. The 8th adhesive sheet 80 is preferably an adhesive sheet similar to the 1st adhesive sheet 10 of the 1st embodiment or the 4th adhesive sheet 40 of the 2nd embodiment as a back grinding sheet. When the eighth adhesive sheet 80 is used as a back grinding sheet, the semiconductor wafer W is bonded with the electrical surface W1 facing the eighth adhesive layer 82 of the eighth adhesive sheet 80. The eighth adhesive sheet 80 as a back grinding sheet is preferably bonded to the electrical surface W1 as the first wafer surface before forming a groove of a specific depth on the semiconductor wafer W.

[Groove forming step] Figure 10B is a diagram for explaining step (PY2). Figure 10B shows a diagram for explaining the step of forming a groove of a specific depth from the side of the electrical surface W1 of the semiconductor wafer W (sometimes referred to as the groove forming step). In the groove forming step, a cutter of a cutting device is used to cut a cut from the side of the 8th adhesive sheet 80 on the semiconductor wafer. At this time, the 8th adhesive sheet 80 is completely cut off, and a cut is cut from the electrical surface W1 of the semiconductor wafer W to a depth shallower than the thickness of the semiconductor wafer W, forming a groove W5. The groove W5 is formed to partition a plurality of circuits W2 formed on the electrical surface W1 of the semiconductor wafer W. The depth of the groove W5 is not particularly limited as long as it is slightly deeper than the thickness of the target semiconductor wafer. When the groove W5 is formed, cutting chips are generated from the semiconductor wafer W. In this embodiment, since the groove W5 is formed while the electrical surface W1 is protected by the eighth adhesive sheet 80, it is possible to prevent the electrical surface W1 or the circuit W2 from being contaminated or damaged by the cutting chips.

[Grinding step] Figure 10C is a diagram for explaining step (PY3). Figure 10C shows a step of sticking the third adhesive sheet 30 to the singulated eighth adhesive sheet 80 (sticking step of the third adhesive sheet) after forming the groove W5 and a step of grinding the back surface W6 as the second surface of the semiconductor wafer W (sometimes referred to as the grinding step). In this embodiment, the semiconductor wafer W is ground from the back surface W6 side using a grinder 500. The thickness of the semiconductor wafer W is reduced by grinding, and finally divided into a plurality of semiconductor chips CP. Grinding is performed from the back surface W6 side until the bottom of the groove W5 is removed, and the semiconductor wafer W is singulated for each circuit W2. Subsequently, the back side is further ground as needed to obtain a semiconductor chip CP of a specific thickness. In this embodiment, the back side W3 as the second wafer surface is ground. The method of this embodiment including the groove forming step and the grinding step is equivalent to the pre-cutting method. In the grinding step of this embodiment, the back side W6 is ground while the 8th substrate 81 side of the 8th adhesive sheet 80 is supported by fixing with a transfer tape or fixing with a vacuum adsorption plate.

[Standing step of the third adhesive sheet] Figure 10D is a diagram for explaining step (PY4). Figure 10D shows a step of sticking the third adhesive sheet 30 to the eighth adhesive sheet 80 side of the semiconductor wafer W after back grinding after the grinding step (sometimes referred to as the third adhesive sheet sticking step). As shown in Figure 10D, the state of the divided plurality of semiconductor chips CP being held by the eighth adhesive sheet 80 and the third adhesive sheet 30 is shown.

[Expansion step] In this embodiment, after the step of pasting the third adhesive sheet in step (PY4), the third adhesive sheet 30 is stretched as in the first embodiment to perform a step of expanding the interval between the plurality of semiconductor chips CP (expansion step: step (P5)). In this embodiment, the third adhesive sheet 30 is also preferably an expansion sheet. Step (P5) of this embodiment can be performed in the same manner as in the first embodiment. In this embodiment, the interval D1 between the plurality of semiconductor chips CP is also preferably the same as in the first embodiment. [Sealing step and other steps] In this embodiment, the sealing step and other steps (rewiring layer formation step and connection step with external terminal electrodes) can also be implemented in the same manner as in the first embodiment.

[Effects of the present embodiment] By adopting the expansion method of the present embodiment using the cutting-first method, the adhesive sheet structure and process can be simplified and the residual slurry can be suppressed compared with the past, as in the first embodiment. Furthermore, a method for manufacturing a semiconductor device including the expansion method of the present embodiment can be provided. In addition, the third adhesive sheet 30 used as the grinding step of the present embodiment uses an expansion sheet, and since the expansion step is performed directly after the grinding step, the process can be further simplified.

[Variations of Implementation Forms] The present invention is not limited to the above-mentioned implementation forms. The present invention includes variations of the above-mentioned implementation forms, etc., within the scope of achieving the purpose of the present invention. For example, the circuits in the semiconductor wafer or semiconductor chip are not limited to the arrangement or shape shown in the diagram. The connection structure between the semiconductor package and the external terminal electrode is also not limited to the embodiments described in the above-mentioned implementation forms. In the above-mentioned implementation forms, the embodiment of manufacturing FO-WLP type semiconductor packages is used as an example for explanation, but the present invention can also be applied to the embodiment of manufacturing other semiconductor packages such as fan-in type WLP. The manufacturing method of the above-mentioned FO-WLP can also change some steps, and can also omit some steps. The cutting in the cutting step can also be performed by irradiating the semiconductor wafer with laser light instead of using the above-mentioned cutting mechanism. For example, by irradiating with laser light, a semiconductor wafer can be completely separated and singulated into a plurality of semiconductor chips. Alternatively, after a modified layer is formed inside the semiconductor wafer by irradiating with laser light, the semiconductor wafer can be broken at the modified layer position by stretching the adhesive sheet in the expansion step described later, and singulated into semiconductor chips CP (stealth dicing, stealth dicing is a registered trademark). In the case of a process for forming a modified layer on a semiconductor wafer W, as one embodiment, a back grinding sheet (e.g., the first adhesive sheet 10) or a surface protection sheet during dicing (e.g., the first adhesive sheet 70 of the second embodiment) can be singulated at the same time as the modified layer is formed by irradiating with laser light for forming the modified layer. Furthermore, in the case of a process for forming a modified layer on a semiconductor wafer W, as another aspect, laser light is irradiated to singulate the back grinding sheet or the surface protection sheet during cutting. In the case of concealed cutting, the laser light irradiation is performed by focusing the laser light in the infrared light region at a focal point set inside the semiconductor wafer. In addition, in these methods, the laser light irradiation can also be performed from either side of the semiconductor wafer. Implementation Example

The present invention is further described in detail with reference to the following examples. The present invention is not limited to the examples. (Preparation of Adhesive Sheet) [Example 1] 62 parts by mass of 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 an acrylic copolymer. A solution of a resin (acrylic acid A) to which 2-isocyanatoethyl methacrylate (manufactured by Showa Denko K.K., product name "CURRANTS MOI" (registered trademark)) is added to the acrylic copolymer (adhesive main agent, solid content 35.0% by mass) is prepared. The addition rate is 100 mol% of 2HEA and 90 mol% of 2-isocyanatoethyl methacrylate in the acrylic copolymer. The weight average molecular weight (Mw) of the obtained resin (acrylic acid A) is 600,000, and Mw/Mn is 4.5. The weight average molecular weight Mw and number average molecular weight Mn converted to standard polystyrene were measured by gel permeation chromatography (GPC), and the molecular weight distribution (Mw/Mn) was calculated from each measured value. UV resin A (10-functional urethane acrylate, manufactured by Mitsubishi Chemical Co., Ltd., product name "UV-5806", Mw=1740, containing a photopolymerization initiator) and a toluene diisocyanate crosslinking agent (manufactured by Japan Polyurethane Industries, Ltd., product name "CORONATE L") as a crosslinking agent were added to the adhesive main agent. For 100 parts by weight of solid content in the adhesive main agent, 50 parts by weight of UV resin A and 0.2 parts by weight of crosslinking agent were added. After addition, the mixture was stirred for 30 minutes to prepare adhesive composition A1.

Next, the prepared adhesive composition A1 solution was applied to a polyethylene terephthalate (PET) release film (manufactured by LINTEC Co., Ltd., product name "SP-PET381031", thickness 38μm) and dried to form an adhesive layer with a thickness of 40μm on the release film. After the adhesive layer was bonded to a polyester polyurethane elastomer sheet (manufactured by SHEEDOM Co., Ltd., product name "HIGRESS DUS202", thickness 100μm) as a base material, the unnecessary end portion in the width direction was cut off to produce an adhesive sheet SA1.

(Method for measuring chip spacing) The adhesive sheet obtained in Example 1 was cut into 210mm×210mm sheets for testing. At this time, the sheets were cut so that the sides of the sheets were parallel or perpendicular to the MD direction of the substrate of the adhesive sheet. The semiconductor chip to be attached to the adhesive sheet was prepared in the following order. A back grinding sheet (manufactured by LINTEC Co., Ltd., product name "E-3125KL") was attached to a 6-inch silicon wafer. Next, the 6-inch silicon wafer was cut from the back grinding sheet side so that 3mm×3mm chips were arranged in 5 rows in the X-axis direction and 5 rows in the Y-axis direction, and a total of 25 chips were cut out. The cut back grinding sheet was attached to each chip. The peeling film of the test sheet is peeled off, and the back grinding sheet side of 25 chips cut out as described above is attached to the center of the exposed adhesive layer. At this time, the chips are arranged in 5 rows in the X-axis direction and 5 rows in the Y-axis direction. Next, the test sheet with the chips attached is set in a biaxially extendable expansion device (partitioning device). FIG11 shows a top view of the expansion device 100. In FIG11, the X-axis and the Y-axis are in a mutually orthogonal relationship, and the positive direction of the X-axis is set to the +X-axis direction, the negative direction of the X-axis is set to the -X-axis direction, the positive direction of the Y-axis is set to the +Y-axis direction, and the negative direction of the Y-axis is set to the -Y-axis direction. The test sheet 200 is placed in the expansion device 100 in such a manner that each side is parallel to the X axis or the Y axis. As a result, the substrate MD direction in the test sheet 200 is parallel to the X axis or the Y axis. In addition, the wafer is omitted in FIG. 11 .

As shown in FIG11 , the expansion device 100 has 5 holding mechanisms 101 in the +X axis direction, the -X axis direction, the +Y axis direction, and the -Y axis direction (a total of 20 holding mechanisms 101). Among the 5 holding mechanisms 101 in each direction, the holding mechanism 101A is located at both ends, the holding mechanism 101C is located in the center, and the holding mechanism 101B is located between the holding mechanism 101A and the holding mechanism 101C. Each side of the test sheet 200 is gripped by the holding mechanisms 101. Here, as shown in FIG11 , one side of the test sheet 200 is 210 mm. And the interval between the holding mechanisms 101 on each side is 40 mm. Furthermore, the distance between the end of one side of the test sheet 200 (the top of the sheet) and the holding mechanism 101A closest to the end of the side is 25 mm. Then, multiple tensions not shown corresponding to the holding mechanisms 101 are applied to the mechanisms to drive the holding mechanisms 101 so that the holding mechanisms 101 move independently. The four sides of the test sheet are fixed with a pinching fixture, and the test sheet is expanded by 200 mm at a speed of 5 mm/s in the X-axis direction and the Y-axis direction. Subsequently, the expanded state of the test sheet 200 is maintained by a ring frame. While maintaining the expanded state, the distance between each chip is measured with a digital microscope, and the average value of the distance between each chip is set as the chip interval. If the chip spacing is 1800 μm or more, it is judged as pass "A", and if the chip spacing is less than 1800 μm, it is judged as fail "B".

(Method for measuring chip arrangement) Measure the deviation rate of adjacent chips from the center line in the X-axis and Y-axis directions of the workpiece with the measured chip spacing. Figure 12 shows a schematic diagram of the specific measurement method. Select a row of 5 chips arranged in the X-axis direction, and measure the distance Dy between the top and bottom of the chip in the row with a digital microscope. Calculate the deviation rate in the Y-axis direction based on the following formula (number 3). Sy is the chip size in the Y-axis direction, which is set to 3mm in this embodiment. Y-axis deviation rate [%] = [(Dy-Sy)/2]/Sy×100 … (number 3) For the other four rows of 5 chips arranged in the X-axis direction, the deviation rate in the Y-axis direction is also calculated in the same way. Select a row of 5 chips arranged in the Y-axis direction, and use a digital microscope to measure the distance Dx between the leftmost end and the rightmost end of the chip in the row. Calculate the offset rate in the X-axis direction based on the following formula (4). Sx is the chip size in the X-axis direction, which is set to 3mm in this embodiment. Offset rate in the X-axis direction [%] = [(Dx-Sx)/2]/Sx×100 …(4) For the other four rows of 5 chips arranged in the Y-axis direction, the offset rate in the X-axis direction is also calculated. The reason for dividing by 2 in formulas (3) and (4) is to express the maximum distance of the chip offset from a specific position after expansion as an absolute value. If the deviation rate is less than ±10% in all rows (10 rows in total) in the X-axis direction and the Y-axis direction, it is judged as qualified "A". If it is more than ±10% in more than one row, it is judged as unqualified "B".

(Evaluation method of residual blur) After expanding the conditions described in the aforementioned chip spacing measurement method, use a UV irradiation device ("RAD-2000 m/12" manufactured by LINTEC Co., Ltd.) to irradiate the surface of the adhesive sheet of Example 1 opposite to the surface on which the chip is mounted with UV light at an illumination of 220mW/ ^cm2 and a light quantity of 460mJ/ ^cm2 . After UV irradiation, hold the chip with an adsorption table and peel off the adhesive sheet. After peeling off the adhesive sheet, observe the surface of the chip with the adhesive sheet attached with an optical microscope. If no residual blur is observed on the chip surface, it is judged as qualified "A", and if residual blur is observed, it is judged as unqualified "B". After the adhesive sheet of Example 1 was expanded, the evaluation results of the chip spacing were judged as qualified "A", and the evaluation results of the chip alignment were judged as qualified "A". After the back grinding sheet was interposed between the chip and the adhesive sheet of Example and the adhesive sheet was expanded, the evaluation result of the residual smear on the chip surface was judged as qualified "A".

3: Sealing body 3A: Surface 10: 1st adhesive sheet 11: 1st substrate 12: 1st adhesive layer 20: 2nd adhesive sheet 21: 2nd substrate 22: 2nd adhesive layer 30: 3rd adhesive sheet 31: 3rd substrate 32: 3rd adhesive layer 40: 4th adhesive sheet 41: 4th substrate 42: 4th adhesive layer 50: 5th adhesive sheet 51: 5th substrate 52: 5th adhesive layer 60: 6th adhesive sheet 61: 6th substrate 62: 6th adhesive layer 70: 1st adhesive sheet 71: 7th substrate 72: 7th adhesive Adhesive layer 80: 8th adhesive sheet 81: 8th substrate 82: 8th adhesive layer 100: Extension device 101, 101A, 101B, 101C: Holding mechanism 200: Test sheet 300: Sealing member 500: Grinding machine W: Semiconductor wafer W1: Surface of the circuit W2: Circuit W3, W6: Back surface W5: Groove CP: Semiconductor chip Sx: Chip size in the X-axis direction Sy: Chip size in the Y-axis direction Dx: Distance between the leftmost end of the chip and the rightmost end of the chip Dy: Distance between the top end of the chip and the bottom end of the chip D1: Interval

[FIG. 1A] is a cross-sectional view illustrating the manufacturing method of the first embodiment. [FIG. 1B] is a cross-sectional view illustrating the manufacturing method of the first embodiment. [FIG. 2A] is a cross-sectional view illustrating the manufacturing method of the first embodiment. [FIG. 2B] is a cross-sectional view illustrating the manufacturing method of the first embodiment. [FIG. 3] is a cross-sectional view illustrating the manufacturing method of the first embodiment. [FIG. 4A] is a cross-sectional view illustrating the manufacturing method of the first embodiment. [FIG. 4B] is a cross-sectional view illustrating the manufacturing method of the first embodiment. [FIG. 5A] is a cross-sectional view illustrating the manufacturing method of the first embodiment. [FIG. 5B] is a cross-sectional view illustrating the manufacturing method of the first embodiment. [FIG. 6A] is a cross-sectional view illustrating the manufacturing method of the second embodiment. [Fig. 6B] is a cross-sectional view illustrating the manufacturing method of the second embodiment. [Fig. 7A] is a cross-sectional view illustrating the manufacturing method of the second embodiment. [Fig. 7B] is a cross-sectional view illustrating the manufacturing method of the second embodiment. [Fig. 8A] is a cross-sectional view illustrating the manufacturing method of the second embodiment. [Fig. 8B] is a cross-sectional view illustrating the manufacturing method of the second embodiment. [Fig. 9] is a cross-sectional view illustrating the manufacturing method of the second embodiment. [Fig. 10A] is a cross-sectional view illustrating the manufacturing method of the third embodiment. [Fig. 10B] is a cross-sectional view illustrating the manufacturing method of the third embodiment. [Fig. 10C] is a cross-sectional view illustrating the manufacturing method of the third embodiment. [Fig. 10D] is a cross-sectional view illustrating the manufacturing method of the third embodiment. [Figure 11] is a top view of a biaxial extension device used in the embodiment. [Figure 12] is a schematic diagram for explaining a method for measuring chip alignment.

10: 1st adhesive sheet

11: The first substrate

12: 1st adhesive layer

30: Third adhesive sheet

31: The third substrate

32: Third adhesive layer

W1: Electric road surface

W2: Circuit

W3: Back

CP: semiconductor chip

D1: Interval

Claims (11)

An expansion method includes attaching a first adhesive sheet having a first adhesive layer and a first substrate to a wafer having a first wafer surface and a second wafer surface on the opposite side of the first wafer surface, attaching a second adhesive sheet having a second adhesive layer and a second substrate to the second wafer surface, cutting a cut from the side of the first adhesive sheet, and further separating the wafer surface. The wafer is singulated into a plurality of chips, a third adhesive sheet having a third adhesive layer and a third substrate is attached to the first substrate, the second adhesive sheet is peeled off from the second wafer surface of the wafer, the third adhesive sheet is stretched to expand the interval between the plurality of chips, and when the third adhesive sheet is stretched, the first wafer surface does not contact the third adhesive layer of the third adhesive sheet. As in the expansion method of claim 1, the aforementioned incision is formed with a depth from the side of the aforementioned first adhesive sheet to the aforementioned second adhesive sheet. As in the expansion method of claim 1, the second wafer surface is formed by grinding the back side of the wafer. As in the extended method of claim 3, before the back side of the wafer is ground, the first adhesive sheet is adhered to the first wafer surface. As in the extended method of claim 3, before the back side of the wafer is ground, the fourth adhesive sheet is adhered to the first wafer surface, and after the back side is ground, the fourth adhesive sheet is peeled off from the first wafer surface, and the first adhesive sheet is adhered to the first wafer surface. As in the expansion method of claim 5, the fourth adhesive sheet is a back grinding sheet, the first adhesive sheet is a surface protection sheet, and the thickness of the surface protection sheet is greater than 5μm and less than 500μm. As in the expansion method of claim 1, wherein the first adhesive sheet is a back-grinding sheet. As in the expansion method of claim 1, wherein the third adhesive sheet is an expansion sheet. As in the expansion method of claim 1, wherein the aforementioned wafer is a semiconductor wafer. An expansion method as in any one of claims 1 to 9, wherein the first wafer surface has a circuit. A method for manufacturing a semiconductor device, comprising an extended method as described in any one of claims 1 to 10.

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