TWI837290B - Expansion method and method of manufacturing semiconductor device - Google Patents

Abstract

The present invention relates to an expansion method, which comprises attaching a first adhesive film (10) having a first adhesive layer (12) and a first substrate (11) to the second wafer surface of a wafer having a first wafer surface and a second wafer surface on the opposite side of the first wafer surface, cutting a notch from the first wafer surface side to singulate the wafer into a plurality of chips (CP), further cutting the first adhesive layer (12), peeling the first substrate (11) from the first adhesive layer (12), attaching a second film (20) to the first adhesive layer (12), and stretching the second film (20) to expand 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 type and fan-out type. 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 substrate for supporting the adhesive layer. When the expansion wafer adhesive tape described in Document 1 is stretched, not only the substrate 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 adhesive sheet described in Document 2 is used to perform the expansion step, 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 includes semiconductor devices such as wafers, semiconductor device packages, and micro LEDs. Similar to semiconductor chips, these semiconductor devices may have their spacing expanded.

The object of the present invention is to provide an expansion method that can simplify the tape structure and manufacturing process and suppress the residual paste 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 second wafer surface of a wafer having a first wafer surface and a second wafer surface on the opposite side of the first wafer surface, make an incision from the side of the first wafer surface, singulate the wafer into a plurality of chips, further cut the first adhesive layer, peel off the first substrate from the first adhesive layer, attach a second sheet to the first adhesive layer, and stretch the second sheet to 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 incision is formed to a depth reaching the aforementioned first substrate. In an expansion method of one aspect of the present invention, it is preferred that the aforementioned first adhesive layer contains a first energy ray-curable resin. In an expansion method of one aspect of the present invention, it is preferred that the aforementioned second sheet is an expansion sheet. In an expansion method of one aspect of the present invention, it is preferred that the aforementioned second sheet has a second adhesive layer and a second substrate, and the aforementioned second adhesive layer contains a second energy ray-curable resin. In an expansion method of one aspect of the present invention, it is preferred that the peeling force of the aforementioned first substrate when peeling off from the aforementioned first adhesive layer is 10mN/25mm or more and 2000mN/25mm or less. In an expansion method of one aspect of the present invention, the first adhesive sheet preferably has a peeling layer between the first substrate and the first adhesive layer. In an expansion method of one aspect of the present invention, after the first substrate is peeled off from the first adhesive layer, the plurality of chips to which the first adhesive layer is attached are held by a holding member, and the second sheet is attached to the first adhesive layer attached to the plurality of chips held by the holding member. In an expansion method of one aspect of the present invention, after the wafer is singulated into a plurality of chips, the first adhesive sheet is stretched to expand the interval between the plurality of chips. In an expansion method of one aspect of the present invention, the wafer is preferably 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 an expansion method.

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 implementation form]

The following describes the expansion method of the present embodiment and the method for manufacturing a semiconductor device including the expansion method. FIG. 1 (FIG. 1A and FIG. 1B), FIG. 2 (FIG. 2A and FIG. 2B), and FIG. 3 and FIG. 4 (FIG. 4A and FIG. 4B) 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 has at least the following steps (P1) to (P5). (P1) A step of attaching a first adhesive sheet to the second wafer surface of a wafer having a first wafer surface and a second wafer surface. The first adhesive sheet has a first adhesive layer and a first substrate. (P2) A step of cutting the wafer by cutting the first wafer surface, and further singulating the wafer into a plurality of chips by cutting at least the first adhesive layer. The first wafer surface becomes the electrical surface of the chip, and the second wafer surface becomes the back of the chip. (P3) A step of peeling off the first substrate while leaving the first adhesive layer on the back of the chip. (P4) A step of attaching the second sheet to the first adhesive layer on the back of the chip. (P5) A step of stretching the second sheet to expand the interval between the plurality of chips. Figure 1A is a diagram for explaining step (P1). Figure 1A shows a wafer W with the first adhesive sheet 10 attached.

The semiconductor wafer W has a first wafer surface W1 as a first wafer surface and a back surface W3 as a second wafer surface. A circuit W2 is formed on the first wafer surface W1. A first adhesive sheet 10 is attached to the back surface W3. In the present embodiment, the process is performed with the first wafer surface W1 exposed as an example, but as an example of other embodiments, the process is performed with a protective member such as a protective sheet or a protective film attached to the first wafer surface W1. The first adhesive sheet 10 has a first adhesive layer 12 and a first substrate 11. The details of the first adhesive sheet 10 will be described later. The semiconductor wafer W may be, for example, a silicon wafer, or a compound semiconductor wafer such as gallium and arsenic. 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 through 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 until the wafer has 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 without circuit formation by a grinder. The thickness of the semiconductor wafer W before grinding is not specifically limited, and is usually 500μm to 1000μm. The thickness of the semiconductor wafer W after grinding is not specifically limited, and is usually 20μm to 500μm.

[First adhesive sheet pasting step] 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 first adhesive sheet 10 on the back surface W3. This pasting step is sometimes referred to as the first adhesive sheet pasting step. As described later, in step (P2), the semiconductor wafer W is singulated into a plurality of semiconductor chips CP by dicing. In this embodiment, when the semiconductor wafer W is cut, in order to maintain the semiconductor wafer W, the first adhesive sheet 10 is preferably pasted on the back surface W3. The semiconductor wafer W is pasted with the back surface W3 facing the first adhesive layer 12 of the first adhesive sheet 10.

[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 first adhesive sheet 10. The semiconductor wafer W with the first adhesive sheet 10 attached to the back surface W3 is singulated by cutting to form a plurality of semiconductor chips CP. The electrical surface W1 as the first wafer surface is equivalent to the electrical surface of the chip. The back surface W3 as the second wafer surface is equivalent to the back surface of the chip. In this embodiment, a cut is made from the side of the electrical surface W1 to cut the semiconductor wafer W, and then at least the first adhesive layer 12 of the first adhesive sheet 10 is cut. The first adhesive layer 12 is also cut to the same size as the semiconductor chip CP. Cutting is performed using a cutting mechanism such as a saw or laser. The cutting depth during cutting is not particularly limited as long as it is a depth that can separate the semiconductor wafer W and the first adhesive layer 12 into pieces. In this embodiment, the embodiment in which the cut is not made to the first substrate 11 is used as an example for explanation, but the present invention is not limited to such an embodiment. For example, in other embodiments, based on the viewpoint of surely cutting the semiconductor wafer W and the first adhesive layer 12, a cut with a depth reaching the depth of the first substrate 11 can also be formed by cutting. In addition, the cutting step of this embodiment is to cut along the end face of the semiconductor wafer W, and a cut is formed in the first adhesive layer 12 as shown in FIG. 1B.

[First substrate peeling step] Figure 2A is a diagram for explaining step (P3). This step (P3) is sometimes referred to as the first substrate peeling step. Figure 2A shows the step of peeling the first substrate 11 in a state where the first adhesive layer 12 remains on the back surface W3 of the singulated semiconductor chip CP after dicing. As one embodiment of the first adhesive sheet 10, when the first adhesive layer 12 is directly laminated on the first substrate 11, in the first substrate peeling step, it is preferred to peel the interface between the first adhesive layer 12 and the first substrate 11. When the first substrate 11 is peeled off, a plurality of semiconductor chips CP having the first adhesive layer 12 adhered to the back surface W3 are obtained. In addition, in the peeling step of the first substrate of the present embodiment, the first adhesive layer 12 not adhered to the back surface W3 of the semiconductor chip CP is removed in a state of being adhered to the first substrate 11 as shown in FIG. 2A. The peeling force when the first adhesive layer 12 is peeled off from the first substrate 11 is preferably 10 mN/25 mm or more and 2000 mN/25 mm or less. By setting the peeling force when the first adhesive layer 12 is peeled off from the first substrate 11 to 10 mN/25 mm or more, the semiconductor chip retention during dicing is excellent. By setting the peeling force when the first adhesive layer 12 is peeled off from the first substrate 11 to 2000 mN/25 mm or less, the semiconductor chip pickup after dicing is excellent. The peeling force when the first adhesive layer 12 is peeled off from the first substrate 11 is more preferably 30 mN/25 mm or more and 1000 mN/25 mm or less, and even more preferably 50 mN/25 mm or more and 500 mN/25 mm or less. A tensile test was performed to peel the first substrate 11 from the first adhesive layer 12 using a precision universal testing machine ("Autograph AG-IS" manufactured by Shimadzu Corporation) at a peeling angle of 180°, a measuring temperature of 23°C, and a tensile speed of 300 mm/min. The load measured during the tensile test was set as the peeling force.

[Agglutination step of the second sheet] Figure 2B is a diagram for explaining step (P4). Step (P4) is sometimes referred to as the agglutination step of the second sheet. Figure 2B shows a state where the second sheet 20 is agglutinated to the plurality of semiconductor chips CP obtained by the cutting step. The second sheet 20 of this embodiment has a second adhesive layer 22 and a second substrate 21. The details of the second sheet 20 are described later. In this embodiment, when the second sheet 20 is agglutinated to the back surface W3 side of the plurality of semiconductor chips CP, a laminated structure of the plurality of semiconductor chips CP and the second adhesive layer 22 of the second sheet 20 is obtained with the first adhesive layer 12 singulated between them.

[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 where the second sheet 20 is stretched after the second sheet 20 is pasted to expand the interval between the plurality of semiconductor chips CP. 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 second sheet 20 is preferably an expansion sheet. The method of stretching the second sheet 20 in the expansion step is not particularly limited. Examples of methods for stretching the second thin film 20 include a method of stretching the second thin film 20 by pressing a ring-shaped or circular expander, and a method of pinching the outer periphery of the second thin film 20 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 attached to the second sheet 20 to another adhesive sheet (e.g., the third adhesive sheet) (hereinafter sometimes referred to as the "first transfer step") may also be implemented. FIG. 4A shows a diagram illustrating the step of transferring the plurality of semiconductor chips CP attached to the second sheet 20 to the third adhesive sheet 30 (hereinafter sometimes referred to as the "first transfer step"). The third adhesive sheet 30 is not particularly limited as long as it can hold the plurality of semiconductor chips CP. The third adhesive sheet 30 has a third substrate 31 and a third adhesive layer 32. When the plurality of semiconductor chips CP on the third adhesive sheet 30 are to be sealed, it is preferred to use an adhesive sheet for the sealing step as the third adhesive sheet 30, and it is more preferred to use an adhesive sheet with heat resistance. In addition, when a heat-resistant adhesive sheet is used as the third adhesive sheet 30, it is preferred that the third substrate 31 and the third adhesive layer 32 are respectively formed of heat-resistant materials that can withstand the temperature experienced in the sealing step. In the present embodiment, when the transfer step is performed, it is preferred that, for example, after the expansion step, the third adhesive sheet 30 is adhered to the electrical path W1 of the plurality of semiconductor chips CP, and then the second sheet 20 and the first adhesive layer 12 are peeled off from the back side W3. The second sheet 20 and the first adhesive layer 12 may be peeled off from the back surface W3 together, or the second sheet 20 may be peeled off first and then the first adhesive layer 12 may be peeled off from the back surface W3. The step of peeling the first adhesive layer 12 from the back surface W3 is sometimes referred to as the first adhesive layer peeling step.

After the peeling step of the first adhesive layer, it is also preferable to maintain the interval D1 between the plurality of semiconductor chips CP expanded in the expansion step. When the first adhesive layer 12 is peeled off from the back surface W3, the first adhesive layer 12 preferably contains the first energy ray curable resin from the viewpoint of suppressing the residual paste on the back surface W3. When the first adhesive layer 12 contains the first energy ray curable resin, the first adhesive layer 12 is irradiated with energy rays to cure the first energy ray curable resin. When the first energy ray curable resin is cured, the cohesive force of the first adhesive layer 12 is increased, and the adhesive force between the first adhesive layer 12 and the back surface W3 of the 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. Therefore, the first energy ray curable resin is preferably an ultraviolet curable resin.

In the case where the second sheet 20 has the second adhesive layer 22, the second adhesive layer 22 preferably contains the second energy ray curable resin from the viewpoint that the second sheet 20 is peeled off from the back surface W3 together with the first adhesive layer 12. In the case where the first adhesive layer 12 contains the first energy ray curable resin and the second adhesive layer 22 contains the second energy ray curable resin, the second adhesive layer 22 and the first adhesive layer 12 are irradiated with energy rays from the second substrate 21 side to cure the second energy ray curable resin and the first energy ray curable resin. Examples of energy rays for curing the second energy-curable resin include ultraviolet rays (UV) and electron beams (EB), preferably ultraviolet rays. Therefore, the second energy-curable resin is preferably an ultraviolet-curable resin. The second substrate 21 preferably has energy ray permeability. As a different form from the present embodiment, the first adhesive layer 12 may be used as a protective film for protecting the back surface W3 of the semiconductor chip CP without being peeled off from the back surface W3 of the semiconductor chip CP. When the first adhesive layer 12 is used as a protective film for the back surface W3, the first adhesive layer 12 preferably contains a curable adhesive composition. The third adhesive sheet 30 may also be adhered to the annular frame together with a plurality of semiconductor chips CP. In this case, the annular frame is placed on the third adhesive layer 32 of the third adhesive sheet 30, and is lightly pressed and fixed. Then, the third adhesive layer 32 exposed inside the annular shape of the annular frame is pressed against the electric surface W1 of the semiconductor chip CP, and the plurality of semiconductor chips CP are fixed to the third adhesive sheet 30. Alternatively, the third adhesive layer 32 exposed inside the annular shape of the annular frame is pressed against the first adhesive layer 12 on the back surface W3 of the semiconductor chip CP, and the plurality of semiconductor chips CP are fixed to the third adhesive sheet 30. At this time, the first adhesive layer 12 is interposed between the back surface W3 of the semiconductor chip CP and the third adhesive layer 32.

[Sealing step] FIG. 4B 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 third adhesive sheet 30. 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 third adhesive sheet 30. 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 third adhesive sheet 30, 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 third adhesive sheet 30 is peeled off. When the third adhesive sheet 30 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 third adhesive sheet 30 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 perform an appropriate function in the desired step. The first substrate 11 is a member that supports the first adhesive layer 12. The first substrate 11 is, for example, a resin film. As the resin film, at least one film selected from the group consisting of 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)acrylate copolymer film, polystyrene film, polycarbonate film, polyimide film and fluororesin film is used. Also, as the first substrate 11, a crosslinked film of the above is used. Furthermore, the first substrate 11 may also be a laminated film of the above.

Furthermore, the first substrate 11 may also be a hard support, for example. The material of the hard support can be appropriately determined by considering the mechanical strength and heat resistance. Examples of the material of the hard support include metal materials such as SUS; non-metallic inorganic materials such as glass and silicon wafers; resin materials such as epoxy, ABS, acrylic, engineering plastics, super engineering plastics, polyimide, polyamide imide; composite materials such as glass epoxy resin, etc. Among them, SUS, glass and silicon wafers are preferred. Examples of engineering plastics include nylon, polycarbonate (PC) and polyethylene terephthalate (PET). Examples of super engineering plastics include polyphenylene sulfide (PPS), polyether sulfide (PES) and polyether ether ketone (PEEK). The thickness of the first substrate 11 is not particularly limited. The thickness of the first substrate 11 is preferably not less than 20 μm and not more than 50 mm, and more preferably not less than 60 μm and not more than 20 mm. By setting the thickness of the first substrate 11 to the above range, when the first substrate 11 is a resin film, since the first adhesive sheet 10 has sufficient flexibility, it shows good adhesion to the processing object (workpiece). The processing object (workpiece) is, for example, a wafer or a semiconductor element, and as a more specific example, it is a semiconductor wafer or a semiconductor chip. When the first substrate 11 is a hard support, the thickness of the hard support can be appropriately determined in consideration of mechanical strength and handling properties. The thickness of the hard support is, for example, not less than 100 μm and not more than 50 mm.

・First adhesive layer The first adhesive layer 12 is not particularly limited in terms of its constituent material as long as it can perform appropriate functions in the desired step. In one aspect of the first adhesive layer 12, it 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. In one aspect of the first adhesive layer 12, it is preferably composed of a curable adhesive composition that cures by receiving energy rays from the outside. Examples of the energy supplied from the outside include ultraviolet rays, electron beams, and heat. The first adhesive layer 12 preferably contains at least one of an ultraviolet curing adhesive and a heat curing adhesive. When the first substrate 11 has heat resistance, the adhesive layer is preferably a thermosetting adhesive layer containing a heat curing adhesive because the residual stress during heat curing can be suppressed.

The first adhesive layer 12 contains, for example, a first adhesive composition. The first adhesive composition contains an adhesive polymer component (A) and a curing component (B). (A) Adhesive polymer component In order to impart sufficient adhesiveness and film-forming properties (sheet-forming properties) to the first adhesive layer 12, an adhesive polymer component (A) is used. As the adhesive polymer component (A), conventionally known acrylic polymers, polyester resins, urethane resins, acrylic urethane resins, silicone resins, rubber-based polymers, etc. can be used. The weight average molecular weight (Mw) of the adhesive polymer component (A) is preferably 10,000 to 2,000,000, and more preferably 100,000 to 1,200,000. In this specification, the weight average molecular weight (Mw) is a standard polystyrene conversion value measured by gel permeation chromatography (GPC). Acrylic polymer is preferably used as the adhesive polymer component (A). The glass transition temperature (Tg) of the acrylic polymer is preferably above -60°C and below 50°C, more preferably above -50°C and below 40°C, and even more preferably above -40°C and below 30°C.

Examples of monomers constituting the acrylic polymer include (meth)acrylate monomers or derivatives thereof. For example, (meth)acrylate alkyl esters having an alkyl group with 1 to 18 carbon atoms, specifically methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc. Also, examples include (meth)acrylates having a cyclic skeleton, specifically cyclohexyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, and imido (meth)acrylate. Further, examples of monomers having a functional group include hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, etc. having a hydroxyl group; in addition, examples include glycidyl (meth)acrylate, etc. having an epoxy group. Acrylic polymers are preferred over acrylic polymers containing monomers having a hydroxyl group because they have good compatibility with the curable component (B) described later. In addition, the acrylic polymers may be copolymerized with at least one selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, vinyl acetate, acrylonitrile, and styrene. Furthermore, as the adhesive polymer component (A), a thermoplastic resin may be formulated to maintain the flexibility of the film of the first adhesive layer 12 after curing. The thermoplastic resin preferably has a weight average molecular weight of 1000 to 100,000, more preferably 3000 to 80,000. The glass transition temperature of the thermoplastic resin is preferably -30°C to 120°C, more preferably -20°C to 120°C. Examples of the thermoplastic resin include polyester resin, urethane resin, phenoxy resin, polybutene, polybutadiene or polystyrene. The thermoplastic resins may be used alone or in combination of two or more.

(B) Curing component The curing component (B) is at least one of a thermosetting component and an energy ray curing component. A thermosetting component and an energy ray curing component can also be used as the curing component (B). Thermosetting resins and thermosetting agents are used as the thermosetting component. Epoxy resins are preferred as the thermosetting resin. A conventionally known epoxy resin can be used as the epoxy resin. Specific examples of epoxy resins include multifunctional epoxy resins, bisphenol A diglycidyl ether or its hydrogenated product, o-cresol novolac epoxy resin, dicyclopentadiene epoxy resin, biphenyl epoxy resin, bisphenol A epoxy resin, bisphenol F epoxy resin, phenylene skeleton epoxy resin, etc., which are epoxy compounds having two or more functional groups in the molecule. These can be used alone or in combination of two or more. In the first adhesive layer 12, the thermosetting resin preferably contains 1 to 1000 parts by mass, more preferably 10 to 500 parts by mass, and even more preferably 20 to 200 parts by mass, relative to 100 parts by mass of the adhesive polymer component (A). If the content of the thermosetting resin is 1 part by mass or more, the disadvantage of not being able to obtain sufficient adhesion can be suppressed. If the content of the thermosetting resin is 1000 parts by mass or less, the peeling force between the first adhesive layer 12 and the first substrate 11 can be prevented from becoming too high. If the peeling force is prevented from becoming too high, poor transfer of the first adhesive layer 12 to the back side W3 of the semiconductor chip CP can be prevented.

Thermosetting agents function as hardeners for thermosetting resins, especially epoxy resins. As a preferred thermosetting agent, a compound having two or more functional groups that can react with epoxy groups in one molecule is exemplified. Examples of functional groups that can react with epoxy groups include phenolic hydroxyl groups, alcoholic hydroxyl groups, amino groups, carboxyl groups, and acid anhydride groups. Among them, phenolic hydroxyl groups, amino groups, and acid anhydride groups are preferred, and phenolic hydroxyl groups and amino groups are more preferred. Specific examples of phenolic hardeners include multifunctional phenolic resins, bisphenols, novolac-type phenolic resins, dicyclopentadiene-type phenolic resins, Xyloc-type phenolic resins, and aralkylphenolic resins. A specific example of an amine-based curing agent is DICY (dicyandiamide). Such thermosetting agents may be used alone or in combination of two or more. The content of the thermosetting agent is preferably 0.1 to 500 parts by mass, and more preferably 1 to 200 parts by mass, relative to 100 parts by mass of the thermosetting resin. When the first adhesive layer 12 contains a thermosetting component as the curing component (B), the first adhesive layer 12 has thermosetting properties. In this case, the first adhesive layer 12 can be cured by heating. However, in the first adhesive sheet 10 of this embodiment, when the first substrate 11 has heat resistance, it is difficult for residual stress to be generated in the substrate during the thermal curing of the first adhesive layer 12, thereby causing defects.

As the energy ray-curable component, a low molecular compound (energy ray-polymerizable compound) containing an energy ray-polymerizable group that polymerizes and cures when irradiated with energy rays such as ultraviolet rays or electron beams can be used. Specific examples of such energy ray-curable components include trihydroxymethylpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxy pentaacrylate, dipentaerythritol hexaacrylate, or acrylic compounds such as 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, oligoester acrylate, urethane acrylate oligomer, epoxy-modified acrylate, polyether acrylate, and itaconic acid oligomer. These compounds have at least one polymerizable double bond in the molecule, and generally have a weight average molecular weight of 100 to 30,000, preferably 300 to 10,000. The amount of the energy ray polymerizable compound to be added is preferably 1 to 1500 parts by mass, more preferably 10 to 500 parts by mass, and even more preferably 20 to 200 parts by mass, relative to 100 parts by mass of the binder polymer component (A). In addition, as the energy ray curing component, any energy ray curing polymer formed by bonding the main chain or side chain of the binder polymer component (A) with an energy ray polymerizable group can be used. Such energy ray curing polymers have both the function of the binder polymer component (A) and the function of the curing component (B).

The main skeleton of the energy ray curing polymer is not particularly limited. It can be an acrylic polymer widely used as an adhesive polymer component (A), and can also be polyester, polyether, etc., but based on the ease of synthesis and control of physical properties, acrylic polymer is preferably used as the main skeleton. The energy ray polymerizable group bonded to the main chain or side chain of the energy ray curing polymer is, for example, a group containing a carbon-carbon double bond that is energy ray polymerizable, and specifically, (meth)acryloyl group, etc. can be exemplified. The energy ray polymerizable group can also be bonded to the energy ray curing polymer via an alkylene group, an alkoxyene group, or a polyalkoxyene group. The weight average molecular weight (Mw) of the energy ray curing polymer bonded with the energy ray polymerizable group is preferably 10,000 to 2,000,000, and more preferably 100,000 to 1,500,000. Moreover, the glass transition temperature (Tg) of the energy ray-curing polymer is preferably above -60°C and below 50°C, more preferably above -50°C and below 40°C, and even more preferably above -40°C and below 30°C. The energy ray-curing polymer is obtained by, for example, reacting an acrylic polymer containing a functional group with a compound containing a polymerizable group. Examples of the functional group possessed by the acrylic polymer containing a functional group include, for example, a hydroxyl group, a carboxyl group, an amino group, a substituted amine group, and an epoxy group. The compound containing a polymerizable group is a compound containing a polymerizable group having 1 to 5 substituents that react with the substituent possessed by the acrylic polymer and an energy ray-polymerizable carbon-carbon double bond per molecule. Examples of the substituent that reacts with the functional group include an isocyanate group, a glycidyl group, and a carboxyl group.

Examples of compounds containing polymerizable groups include (meth)acryloyloxyethyl isocyanate, m-isopropenyl-α,α-dimethylbenzyl isocyanate, (meth)acryloyl isocyanate, allyl isocyanate, (meth)glycidyl acrylate, and (meth)acrylic acid. Acrylic polymers are preferably copolymers of (meth)acrylic acid monomers or their derivatives having functional groups such as hydroxyl, carboxyl, amino, substituted amino, and epoxy groups, and other (meth)acrylate monomers or their derivatives that can be copolymerized therewith. Examples of (meth)acrylic acid monomers or their derivatives having functional groups such as hydroxyl, carboxyl, amino, substituted amino, epoxy, etc. include 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate having hydroxyl; acrylic acid, methacrylic acid, itaconic acid having carboxyl; glycidyl methacrylate and glycidyl acrylate having epoxy. Examples of other (meth)acrylate monomers or their derivatives that can be copolymerized with the above-mentioned (meth)acrylic acid monomers include alkyl (meth)acrylates having an alkyl group with a carbon number of 1 to 18, specifically methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. Examples of other (meth)acrylate monomers or derivatives thereof copolymerizable with the (meth)acrylic acid monomer include (meth)acrylates having a cyclic skeleton, specifically cyclohexyl (meth)acrylate, benzyl (meth)acrylate, isobornyl acrylate, dicyclopentyl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, and acylimide acrylate, etc. Furthermore, the acrylic polymer may be copolymerized with at least one selected from the group consisting of vinyl acetate, acrylonitrile, and styrene.

Even when using an energy ray curing polymer, the aforementioned energy ray polymerizable compound can be used in combination, and the adhesive polymer component (A) can also be used in combination. The mixing amount relationship of the three in the first adhesive layer 12 in this embodiment is that the energy ray polymerizable compound is preferably 1 mass part or more and 1500 mass parts or less, more preferably 10 mass parts or more and 500 mass parts or less, and more preferably 20 mass parts or more and 200 mass parts or less, relative to the total mass of the energy ray curing polymer and the adhesive polymer component (A) of 100 mass parts. By giving the first adhesive layer 12 energy ray curability, the first adhesive layer 12 can be cured easily and in a short time, thereby improving the production efficiency of chips with cured films. The cured film can function as a protective film for protecting semiconductor devices. In the past, protective films for semiconductor components such as chips were generally formed by thermosetting resins such as epoxy resins, but the curing temperature of thermosetting resins exceeds 200°C and the curing time requires about 2 hours, which has become an obstacle to improving production efficiency. However, since the energy-ray-curable adhesive layer is cured in a short time by irradiating energy rays, it is easy to form a protective film, which can help improve production efficiency.

・Other components The first adhesive layer 12 may contain the following components in addition to the above-mentioned adhesive polymer component (A) and curable component (B). (C) Colorant In one embodiment, the first adhesive layer 12 contains a colorant (C). By mixing the colorant in the first adhesive layer 12, when the first adhesive layer 12 is cured to form a protective film for the semiconductor chip CP, when the semiconductor device is assembled in a machine, the protective film shields infrared rays etc. generated from surrounding devices, thereby preventing the semiconductor device from malfunctioning due to such infrared rays etc. In addition, when the product number etc. is printed on the cured film (protective film) obtained by curing the first adhesive layer 12 containing the colorant (C), the visibility of the text is improved. That is, on a semiconductor device or semiconductor chip formed with a protective film, a product number or the like is usually printed on the surface of the protective film by laser marking (a method of printing by removing the surface of the protective film with laser light). Since the protective film contains a colorant (C), the contrast difference between the portion of the protective film removed by laser light and the portion not removed can be fully obtained, thereby improving visibility. As the colorant (C), at least one of an organic pigment, an inorganic pigment, an organic dye, and an inorganic dye is used. As the colorant (C), a black pigment is preferably used from the viewpoint of electromagnetic wave or infrared ray shielding. As the black pigment, carbon black, iron oxide, manganese dioxide, aniline black, activated carbon, etc. are used, but are not limited to them. From the viewpoint of improving the reliability of semiconductor devices, carbon black is particularly preferred as the colorant (C). The colorant (C) may be used alone or in combination of two or more. The high curability of the first adhesive layer 12 in this embodiment is particularly well demonstrated when a colorant that reduces the transmittance of at least one of visible light and infrared rays and both ultraviolet rays is used to reduce the transmittance of ultraviolet rays. As a colorant that reduces the transmittance of at least one of visible light and infrared rays and both ultraviolet rays, in addition to the above-mentioned black pigment, it is not particularly limited if it is a colorant that has absorption or reflection in the wavelength region of at least one of visible light and infrared rays and both ultraviolet rays. The amount of the colorant (C) is preferably 0.1 to 35 parts by mass, more preferably 0.5 to 25 parts by mass, and even more preferably 1 to 15 parts by mass, based on 100 parts by mass of the total solid content constituting the first adhesive layer 12.

(D) Hardening accelerator The hardening accelerator (D) is used to adjust the hardening speed of the first adhesive layer 12. The hardening accelerator (D) is preferably used when epoxy resin and thermosetting agent are used in the hardening component (B). Preferred examples of hardening accelerators include tertiary amines such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol; imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole; organic phosphines such as tributylphosphine, diphenylphosphine, and triphenylphosphine; and tetraphenylborates such as tetraphenylphosphonium tetraphenylborate and triphenylphosphine tetraphenylborate. These hardening accelerators can be used alone or in combination of two or more. The curing accelerator (D) is contained in an amount of preferably 0.01 to 10 parts by mass, more preferably 0.1 to 1 part by mass, based on 100 parts by mass of the curing component (B).

(E) Coupling agent The coupling agent (E) is used to improve at least one of the adhesion and tightness of the first adhesive layer 12 to the semiconductor element and the cohesion of the cured film (protective film). In addition, by using the coupling agent (E), the water resistance of the cured film (protective film) obtained by curing the first adhesive layer 12 can be improved without damaging the heat resistance. As the coupling agent (E), it is preferred to use a compound having a group that reacts with the functional group possessed by the adhesive polymer component (A), the curing component (B), etc. As the coupling agent (E), a silane coupling agent is preferably used. Examples of such coupling agents include γ-glycidyloxypropyltrimethoxysilane, γ-glycidyloxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-(methacryloyloxypropyl)trimethoxysilane, γ-aminopropyltrimethoxysilane, N-6-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-6-(aminoethyl)- γ-aminopropylmethyldiethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, γ-butylpropyltrimethoxysilane, γ-butylpropylmethyldimethoxysilane, bis(3-triethoxysilylpropyl)tetrasulfide, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, imidazolesilane, etc. These coupling agents (E) can be used alone or in combination of two or more. The coupling agent (E) is generally contained in an amount of 0.1 to 20 parts by mass, preferably 0.2 to 10 parts by mass, and even more preferably 0.3 to 5 parts by mass, based on 100 parts by mass of the total of the binder polymer component (A) and the curing component (B).

(F) Inorganic filler By adding an inorganic filler (F) to the first adhesive layer 12, the thermal expansion coefficient of the cured film (protective film) after curing can be adjusted. Preferable examples of inorganic fillers include powders of silicon oxide, aluminum oxide, talc, calcium carbonate, titanium oxide, iron oxide, silicon carbide and boron nitride, spherical beads of the same, single crystal fibers and glass fibers. Among the inorganic fillers, silicon oxide fillers and aluminum oxide fillers are preferred. The above-mentioned inorganic fillers (F) can be used alone or in combination of two or more. The content of the inorganic filler (F) can be adjusted within a range of 1 to 80 parts by mass relative to 100 parts by mass of the total solid content constituting the adhesive layer.

(G) Photopolymerization initiator When the first adhesive layer 12 contains an energy ray curing component as the aforementioned curing component (B), it is irradiated with energy rays such as ultraviolet rays during use to cure the energy ray curing component. At this time, since the composition constituting the first adhesive layer 12 contains a photopolymerization initiator (G), the polymerization curing time can be shortened, thereby reducing the amount of light exposure. Specific examples of such photopolymerization initiators (G) 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, α-hydroxycyclohexylphenyl ketone, benzyl diphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, biphenyl acyl, diphenyl acyl, diacetyl, 1,2-diphenylmethane, 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone, 2,4,6-trimethylbenzyldiphenylphosphine oxide, and β-chloroanthraquinone. The photopolymerization initiator (G) may be used alone or in combination of two or more. The mixing ratio of the photopolymerization initiator (G) is preferably 0.1 to 10 parts by mass, and more preferably 1 to 5 parts by mass, relative to 100 parts by mass of the energy ray curable component. If the mixing ratio of the photopolymerization initiator (G) is 0.1 parts by mass or more, the defect of not being able to obtain satisfactory transferability due to insufficient photopolymerization can be prevented. If the mixing ratio of the photopolymerization initiator (G) is 10 parts by mass or less, the defect of insufficient curability of the first adhesive layer 12 due to the generation of residues that do not contribute to photopolymerization can be prevented.

(H) Crosslinking agent In order to adjust the initial adhesion and cohesive force of the first adhesive layer 12, a crosslinking agent may be added to the first adhesive layer 12. Examples of the crosslinking agent (H) include organic polyisocyanate compounds and organic polyimide compounds. As the above-mentioned organic polyisocyanate compounds, aromatic polyisocyanate compounds, aliphatic polyisocyanate compounds, alicyclic polyisocyanate compounds and trimers of these organic polyisocyanate compounds, and terminal isocyanate urethane prepolymers obtained by reacting these organic polyisocyanate compounds with polyol compounds can be cited. Examples of organic polyisocyanate compounds include 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, trihydroxymethylpropane addition toluene diisocyanate, and lysine isocyanate. Examples of the organic polyimide compound include N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide), trihydroxymethylpropane-tri-β-aziridine propionate, tetrahydroxymethylmethane-tri-β-aziridine propionate, and N,N'-toluene-2,4-bis(1-aziridinecarboxamide) triethylmelamine. The crosslinking agent (H) is usually used in a ratio of 0.01 to 20 parts by mass, preferably 0.1 to 10 parts by mass, and more preferably 0.5 to 5 parts by mass, relative to 100 parts by mass of the total of the binder polymer component (A) and the energy ray-curing polymer.

(I) Widely used additives In addition to the above, various additives can be formulated in the first adhesive layer 12 as needed. Examples of various additives include leveling agents, plasticizers, antistatic agents, antioxidants, ion scavengers, aggregating agents, and chain transfer agents. The first adhesive layer composed of the above components has adhesiveness and hardening properties, and can be easily bonded to a workpiece (semiconductor wafer or chip, etc.) by pressing in an unhardened state. In addition, the first adhesive layer 12 can be a single-layer structure, and can be a multi-layer structure as long as it contains one or more layers containing the above components. The thickness of the first adhesive layer 12 is not particularly limited. The thickness of the first adhesive layer 12 is preferably 3 μm to 300 μm, more preferably 5 μm to 250 μm, and even more preferably 7 μm to 200 μm. The above is a description of the first adhesive layer 12.

・Peeling sheet The peeling sheet can 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. The peeling sheet is a peeling sheet with at least one side subjected to peeling treatment. Specifically, an 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 constituting the peeling sheet substrate include polyester resin films such as polyethylene terephthalate resin, polybutylene terephthalate resin, and polyethylene naphthalate resin, and polyolefin resins such as polypropylene resin and polyethylene resin. Examples of the stripping agent include silicone resins, olefin resins, isoprene resins, butadiene resins, rubber elastomers, long-chain alkyl resins, alkyd resins, and fluorine resins. 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.

The first adhesive sheet is not limited to the sheet structure shown in FIG. 1A. Depending on the type of the first adhesive layer, there is a preferred combination of the first substrate and the first adhesive layer. For example, when the first adhesive layer is an uncured adhesive layer, the first substrate is a resin film monomer, or it can be the aforementioned peeling sheet. When the aforementioned peeling sheet is used as the first substrate, the first adhesive layer is preferably laminated on the peeling layer. For example, when the first adhesive layer is a curable adhesive layer, the first substrate is a resin film monomer, or it can be the aforementioned peeling sheet. When the aforementioned peeling sheet is used as the first substrate, the first adhesive layer is preferably laminated on the peeling layer. In addition, when the first adhesive layer is a curable adhesive layer, the first adhesive sheet preferably has another curable adhesive layer (sometimes referred to as the fourth adhesive layer) between the first substrate and the curable first adhesive layer. The curable fourth adhesive layer preferably contains a curable adhesive known in the past or a curable adhesive described in this specification. The first adhesive layer and the fourth adhesive layer are preferably different compositions. When the cured film of the first adhesive layer is used as a protective film for protecting the back side of the semiconductor chip, the first adhesive layer and the fourth adhesive layer are cured and can be easily peeled off at the interface between the cured film of the first adhesive layer and the cured film of the fourth adhesive layer.

・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. Moreover, as another more specific example of the method for manufacturing an 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. Then, 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) 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 40μm or more, and more preferably 60μm or more. The thickness of the first adhesive sheet 10 is preferably 200μm or less, and more preferably 150μm or less.

(Second sheet) The second 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 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 second substrate 21 preferably has a first substrate surface and a second substrate surface opposite to the first substrate surface. In the second sheet 20, the second adhesive layer 22 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 second substrate 21 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 stretch to a large extent, it is preferred to use a resin with a relatively low glass transition temperature (Tg) as the material of the second substrate 21. The glass transition temperature (Tg) of such resins is preferably below 90°C, more preferably below 80°C, and even more preferably below 70°C. 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, from the viewpoint of being easy to stretch to a large extent, it is preferred to use urethane elastomers.

Urethane elastomers are generally obtained by reacting long-chain polyols, chain extenders, and diisocyanates. Urethane elastomers are composed of soft segments and hard segments, the soft segments have constituent units derived from long-chain polyols, and the hard segments have a polyurethane structure obtained by reacting chain extenders and diisocyanates. Urethane elastomers are classified into polyester polyurethane elastomers, polyether polyurethane elastomers, and polycarbonate polyurethane elastomers according to the type of long-chain polyols. 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 Corporation), 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 Corporation). 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. The rubber materials may be used alone or in combination of two or more. The second substrate 21 is not a laminated film formed by laminating multiple films made of the above-mentioned materials (e.g., thermoplastic elastomers or rubber materials), but is preferably a single-layer film. Furthermore, the second substrate 21 is not a laminated film formed by laminating a film made of the above-mentioned material (e.g., thermoplastic elastomer or rubber material) with other films, but is preferably a single-layer film. The second substrate 21 may also contain additives in a film made of the above-mentioned resin material as the main material. Specific examples of additives are the same as the additives given as examples of the first substrate 11. Examples of additives include pigments, dyes, flame retardants, plasticizers, antistatic agents, lubricants, and fillers. Examples of pigments include titanium dioxide and carbon black. Examples of fillers include organic materials such as melamine resins, inorganic materials such as fumed silica, and metal materials such as nickel particles. The content of the additives that can be contained in the film is not particularly limited, but is preferably limited to a range in which the second substrate 21 can exert the desired function.

The second substrate 21, like the first substrate 11, can also be subjected to treatment on one or both sides of the second substrate 21 to improve adhesion with the second adhesive layer 22 laminated on the surface of the second substrate 21. When the second adhesive layer 22 contains an energy ray-curing adhesive, the second substrate 21 is preferably transparent to the energy ray. When ultraviolet rays are used as energy rays, the second substrate 21 is preferably transparent to ultraviolet rays. When electron beams are used as energy rays, the second substrate 21 is preferably transparent to electron beams. The thickness of the second substrate 21 is not particularly limited as long as the second sheet 20 can function properly in the desired step. The thickness of the second substrate 21 is preferably 20 μm or more, and more preferably 40 μm or more. Furthermore, the thickness of the second substrate 21 is preferably 250 μm or less, and more preferably 200 μm or less.

Furthermore, the standard deviation of the thickness of the second substrate 21 when the thickness of multiple parts is measured at intervals of 2 cm on the first substrate surface or the second substrate surface of the second substrate 21 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 second sheet 20 has a highly accurate thickness, and the second sheet 20 can be stretched uniformly. The tensile modulus of elasticity in the MD direction and CD direction of the second substrate 21 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 second substrate 21 at 23°C is preferably 3 MPa or more and 20 MPa or less, respectively. By making the tensile modulus of elasticity and 100% stress within the above range, the second sheet 20 can be stretched significantly.

The 100% stress of the second substrate 21 is a value obtained as follows. A test piece of 150 mm (length direction) × 15 mm (width direction) size is cut out from the second substrate 21. 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 second substrate 21 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 second substrate 21 is calculated as 15 mm in the width direction × the thickness of the second substrate 21 (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 second substrate 21 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 second substrate 21 in the MD direction and the CD direction 100% or more, respectively, without causing rupture, the second sheet 20 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 clamp distance 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).

・Second adhesive layer The second adhesive layer 22 is not particularly limited in terms of its constituent material as long as it can perform an appropriate function in the desired step such as the expansion step. Examples of the adhesive contained in the second adhesive layer 22 include rubber adhesives, acrylic adhesives, silicone adhesives, polyester adhesives, and urethane adhesives.

・Energy ray curing resin (ax1) The second adhesive layer 22 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 curable 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 curable resin (a1) can be used alone or in combination of two or more. The molecular weight of the energy ray curable resin (ax1) is usually 100 to 30,000, preferably 300 to 10,000.

・(Meth)acrylic copolymer (b1) The second adhesive layer 22 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 the present embodiment, the second adhesive layer 22 preferably contains an energy ray-curable resin (ax1) and an energy ray-curable (meth)acrylic copolymer (b1). The second adhesive layer 22 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 even more preferably 25 parts by mass or more, relative to 100 parts by mass of the (meth)acrylic copolymer (b1). The second adhesive layer 22 preferably contains the energy ray-curable resin (ax1) in an amount of 80 parts by mass or less, more preferably 70 parts by mass or less, and even 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. 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. 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, adamantyl (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 to six, and more preferably one to four 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 second adhesive layer 22 contains a UV-curable compound (e.g., UV-curable resin), the second adhesive layer 22 preferably contains a photopolymerization initiator (CX). By making the second adhesive layer 22 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 (G) in the description of the first adhesive sheet 10. In the second sheet 20, the photopolymerization initiator (CX) can be used alone or in combination of two or more.

When the energy ray curable resin (ax1) and the (meth) acrylic copolymer (b1) are mixed in the adhesive layer, 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). In addition, when the energy ray curable resin (ax1) and the (meth) acrylic copolymer (b1) are mixed in the adhesive layer, 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 appropriate components may be mixed into the second adhesive layer 22. Examples of other components include a crosslinking agent (EX).

・Crosslinking agent (EX) As the crosslinking agent (EX), a compound reactive with the functional group of the (meth)acrylic copolymer (b1) or the like can be used. Examples of the multifunctional compound in the second sheet 20 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. The amount of the crosslinking agent (EX) to be added 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 (E) 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 second adhesive layer 22 is not particularly limited. The thickness of the second adhesive layer 22 is preferably 10 μm or more, and more preferably 20 μm or more. Moreover, the thickness of the second adhesive layer 22 is preferably 150 μm or less, and more preferably 100 μm or less. The recovery rate of the second sheet 20 is preferably 70% or more, more preferably 80% or more, and more preferably 85% or more. The recovery rate of the second sheet 20 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 measured by cutting a test piece of 150mm (length direction) × 15mm (width direction) from a self-adhesive sheet, pinching the two ends in the length direction with a pinching clamp so that the length between the pinching clamps becomes 100mm, then stretching the length between the pinching clamps to 200mm at a speed of 200mm/min, keeping the length between the pinching clamps expanded to 200mm for 1 minute, and then restoring the length between the pinching clamps in the length direction at a speed of 200mm/min until the length between the pinching clamps becomes 100mm. After the length between the clamps 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 clamps is measured when the measured value of the tensile force shows 0.1N/15mm. The length between the clamps minus the initial length between the clamps of 100mm is set as L2 (mm). The length between the clamps in the above expanded state of 200mm minus the initial length between the clamps 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 part that is extremely stretched, 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, it 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 second sheet 20 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 obtained by peeling a plastic film with a peeling agent. The peeling sheet may be a peeling sheet that can be used for the first adhesive sheet 10. The thickness of the second sheet 20 is preferably 30 μm or more, and more preferably 50 μm or more. The thickness of the second sheet 20 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 second sheet 20 is stretched, the back surface W3 of the semiconductor chip CP does not contact the second adhesive layer 22 of the second sheet 20. In each of the semiconductor chips CP, since the back surface W3 and the second adhesive layer 22 are interposed by the first adhesive layer 12 of the first adhesive sheet 10 singulated in the dicing step, even if the second sheet 20 is stretched, the first adhesive layer 12 in contact with the back surface W3 is not stretched. As a result, according to the expansion method of the present embodiment, residual slurry can be suppressed. In addition, in the present embodiment, during the dicing step, the semiconductor wafer W is not supported by the dicing sheet, but supported by the first adhesive sheet 10. Therefore, in order to form a layer (the first adhesive layer 12 in this embodiment) for protecting the back side W3 of the semiconductor chip CP after cutting, it is also possible not to perform the step of replacing the adhesive sheet used in the cutting step with another adhesive sheet. If the first substrate 11 and the first adhesive layer 12 are peeled off, a layer for protecting the back side W3 can be formed. Furthermore, before performing the expansion step, in order to replace the adhesive sheet used in the cutting step with the adhesive sheet used in the expansion step, it is not necessary to carefully control the cutting depth so that the cutting blade in the cutting step does not reach the substrate of the cutting sheet. Therefore, according to the expansion method of this embodiment, the tape structure and process can be simplified and the residual slurry can be suppressed compared with the past. Furthermore, a method for manufacturing 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 second sheet 20 used in the expansion step has a laminated structure of a second substrate 21 and a second adhesive layer 22. In contrast, in the second embodiment, the second sheet 20A used in the expansion step has a single-layer structure composed of a second substrate 21A. 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.

FIG5 shows a diagram for explaining the "second sheet pasting step" of the second embodiment. In this embodiment, after the "first substrate peeling step", as shown in FIG5, the second sheet 20A is pasted on the first adhesive layer 12 pasted on the back surface W3 of the semiconductor chip CP. The second sheet 20A of this embodiment is a single-layer structure composed of the second substrate 21A as described above. Unlike the second sheet 20, the second sheet 20A does not have an adhesive layer, etc., but because the first adhesive layer 12 is sticky, the semiconductor chip CP can be supported on the second substrate 21A through the first adhesive layer 12. As a specific example of the second substrate 21A, the same substrate as the second substrate 21 described in the first embodiment can be used. FIG. 6 shows a diagram for illustrating the "expansion step" of the second embodiment. As shown in FIG. 6, the plurality of semiconductor chips CP supported on the second sheet 20A via the first adhesive layer 12 are spaced apart from each other by expanding the second sheet 20A. Since the second substrate 21A side of the first adhesive layer 12 is preferentially stretched in the thickness direction of the first adhesive layer 12 by the expansion, the back side W3 of the semiconductor chip CP of the first adhesive layer 12 is difficult to deform. The expansion method of the second embodiment and the method for manufacturing a semiconductor device including the expansion method can be implemented in the same manner as the first embodiment in other aspects.

[Effects of the present embodiment] According to the expansion method of the present embodiment, as in the first embodiment, the tape structure and process can be simplified compared to the past and the residual paste can be suppressed. Furthermore, a method for manufacturing a semiconductor device including the expansion method of the present embodiment can be provided. In addition, according to the present embodiment, the expansion sheet is not an adhesive sheet composed of an adhesive layer and a substrate layer, but a second sheet 20A having a single-layer structure composed of a second substrate 21A with a simpler structure, so that the interval between multiple semiconductor chips CP can be expanded.

[Third embodiment] Next, the third embodiment of the present invention will be described. The first embodiment and the third embodiment differ mainly in the following aspects. In the first embodiment, the semiconductor wafer W is bonded to the first adhesive sheet 10 having the first substrate 11 and the first adhesive layer 12. In contrast, in the third embodiment, the semiconductor wafer W is bonded to the first adhesive sheet 10A including the intermediate adhesive layer 13 between the first substrate 11 and the first adhesive layer 12. 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.

FIG. 7A is a diagram for explaining step (P1) of the third embodiment (a step of preparing a wafer W to attach the first adhesive sheet 10A to the back surface W3). FIG. 7A shows a wafer W to which the first adhesive sheet 10A is attached. The first adhesive sheet 10A has a first substrate 11, a first adhesive layer 12, and an intermediate adhesive layer 13. The first adhesive sheet 10A includes an intermediate adhesive layer 13 between the first substrate 11 and the first adhesive layer 12. The first substrate 11 of the first adhesive sheet 10A uses the same substrate as the first substrate described in the first embodiment. The first adhesive layer 12 of the first adhesive sheet 10A uses the same adhesive layer as the first adhesive layer 12 described in the first embodiment. The first adhesive layer 12 of this embodiment preferably contains a curable adhesive bonding agent composition that is cured by receiving energy from the outside. In the first adhesive sheet 10A, the first adhesive layer 12 is laminated on the middle adhesive layer 13 provided on the first substrate 11.

The intermediate adhesive layer 13 may be formed of a weak adhesive having an adhesive force that can be peeled off from the first adhesive layer 12, or may be formed of an energy-ray-hardening adhesive whose adhesive force is reduced by irradiation with energy rays. In addition, when an adhesive layer formed of an energy-ray-hardening adhesive is used as the intermediate adhesive layer 13, energy rays are irradiated in advance in the area where the first adhesive layer 12 is laminated (e.g., the inner periphery of the first substrate 11) to reduce the adhesiveness in advance, while energy rays are not irradiated in other areas (e.g., the outer periphery of the first substrate 11), and the adhesive force can be maintained high for the purpose of, for example, sticking to a jig. In order to prevent only other areas from being irradiated with energy beams, an energy beam shielding layer may be provided on the area corresponding to other areas of the first substrate 11 by printing, and energy beam irradiation may be performed from the side of the first substrate 11. The intermediate adhesive layer 13 may be formed by various adhesives known in the past. The intermediate adhesive layer 13 may be formed by at least one adhesive selected from the group consisting of widely used adhesives, energy beam curing adhesives, and adhesives containing thermal expansion components. As a widely used adhesive, it is preferred to use at least one adhesive selected from the group consisting of, for example, rubber adhesives, acrylic adhesives, silicone adhesives, urethane adhesives, and vinyl ether adhesives. Furthermore, the form of the intermediate adhesive layer 13 also includes a form having a core material and adhesive layers provided on both surfaces of the core material.

Furthermore, the intermediate adhesive layer 13 is also preferably a thermal expansion adhesive layer. The thermal expansion adhesive layer is formed with a thermal expansion adhesive. The thermal expansion adhesive contains an adhesive and a thermal expansion component. When the intermediate adhesive layer 13 is a thermal expansion adhesive layer, the contact area between the thermal expansion adhesive layer and the adherend is reduced by heating, thereby reducing the adhesive force. Thermal expansion microparticles can be used as thermal expansion components. Thermal expansion microparticles are microparticles in which a substance that is easily vaporized and expanded by heating is enclosed in an elastic shell. Examples of substances that expand upon gasification include isobutane, propane, and pentane. In particular, thermally expandable microparticles are preferred because the surface shape of the adhesive layer can be easily controlled after thermal expansion, thereby allowing the adhesive layer to change from a state of strong self-adhesion to a state of easy peeling by heating. In addition, a foaming agent can also be used as a thermally expandable component. A foaming agent is, for example, a chemical substance that has the ability to generate gas by thermal decomposition. Examples of the generated gas include water, carbon dioxide, and nitrogen. By dispersing the foaming agent in the adhesive, an effect similar to that of thermally expandable microparticles is exerted. The thickness of the intermediate adhesive layer 13 is not particularly limited. The thickness of the intermediate adhesive layer 13 is usually in a range of 1 μm to 50 μm, preferably in a range of 5 μm to 30 μm.

[Cutting step] Figure 7B is a diagram for explaining the cutting step of this embodiment. Figure 7B shows a plurality of semiconductor chips CP held by the first adhesive sheet 10A. The semiconductor wafer W with the first adhesive sheet 10A 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 electrical path W1 to cut the semiconductor wafer W, and then at least the first adhesive layer 12 of the first adhesive sheet 10A is cut. The first adhesive layer 12 is also cut to the same size as the semiconductor chip CP. Cutting is performed using a cutting mechanism such as a cutting saw. The cutting depth during cutting is not particularly limited if it is a depth that can separate the semiconductor wafer W and the first adhesive layer 12. In this embodiment, the example in which the cut does not reach the middle adhesive layer 13 and the first substrate 11 is used for explanation, but the present invention is not limited to such an example. For example, in other embodiments, based on the viewpoint of surely cutting the semiconductor wafer W and the first adhesive layer 12, a cut reaching the depth of the middle adhesive layer 13 or a cut reaching the depth of the first substrate 11 can be formed by cutting. In addition, the cutting step of this embodiment is to cut along the end face of the semiconductor wafer W, and a cut is formed in the first adhesive layer 12 as shown in FIG. 7B.

[Step of peeling the first substrate and the intermediate adhesive layer] Figure 7C is a diagram for explaining step (P3) of this embodiment. This embodiment peels the first substrate 11 and the intermediate adhesive layer 13 from the first adhesive layer 12 after the dicing step. This step is sometimes referred to as the step of peeling the first substrate and the intermediate adhesive layer. Figure 7C shows the step of peeling the first substrate 11 and the intermediate adhesive layer 13 in a state where the first adhesive layer 12 remains on the back surface W3 of the singulated semiconductor chip CP after dicing. In the peeling step, the first adhesive layer 12 and the intermediate adhesive layer 13 are peeled at the interface. When the first substrate 11 and the intermediate adhesive layer 13 are peeled, a plurality of semiconductor chips CP with the first adhesive layer 12 attached to the back surface W3 are obtained. In addition, in the peeling step of the first substrate of the present embodiment, the first adhesive layer 12 that is not attached to the back surface W3 of the semiconductor chip CP is removed in a state of being attached to the intermediate adhesive layer 13 as shown in FIG. 7C .

The peeling force when peeling the first substrate 11 and the intermediate adhesive layer 13 from the first adhesive layer 12 is preferably 50 mN/25 mm or more and 2000 mN/25 mm or less. By setting the peeling force when peeling the first substrate 11 and the intermediate adhesive layer 13 from the first adhesive layer 12 to 50 mN/25 mm or more, the effect of excellent wafer retention during dicing is obtained. By setting the peeling force when peeling the first substrate 11 and the intermediate adhesive layer 13 from the first adhesive layer 12 to 2000 mN/25 mm or less, the effect of excellent easy peeling is obtained. The peeling force when peeling the first substrate 11 and the intermediate adhesive layer 13 from the first adhesive layer 12 is preferably 50mN/25mm to 2000mN/25mm, and more preferably 100mN/25mm to 1500mN/25mm. In this embodiment, a tensile test is performed to peel the first substrate 11 and the intermediate adhesive layer 13 from the first adhesive layer 12, similarly to the peeling force when peeling the first substrate 11 from the first adhesive layer 12, and the load measured during the tensile test is set as the peeling force. Regarding the expansion method of the third embodiment and the method for manufacturing a semiconductor device including the expansion method, other aspects can be implemented in the same manner as the first embodiment. [Effects of the present embodiment] By the expansion method of the present embodiment, as in the first embodiment, the tape structure and process can be simplified and the residual paste can be suppressed compared to the past. Furthermore, according to the expansion method of the present embodiment, the deformation of the first adhesive layer 12 can be suppressed compared to the second embodiment. Furthermore, a method for manufacturing a semiconductor device including the expansion method of the present embodiment can be provided.

[Fourth embodiment] Next, the fourth embodiment of the present invention will be described. The first embodiment and the fourth embodiment differ mainly in the following aspects. In the fourth embodiment, before the step of peeling off the first substrate 11 (step (P3)) and after the cutting step, a fourth adhesive sheet 40 as a holding member is adhered to the electrical path W1 of the plurality of semiconductor chips CP. The holding member is not limited to an adhesive sheet, as long as it is a member (such as an adsorption holding table, etc.) that can hold the plurality of semiconductor chips CP during the peeling off of the first substrate 11. In the following description, the main difference from the first embodiment is described, and the repeated description is omitted or simplified. The same symbols are given to the same components as the first embodiment, and the description is omitted or simplified.

[4th adhesive sheet pasting step] FIG. 8A is a diagram for explaining the step of pasting the 4th adhesive sheet 40 on the electric surface W1 of the plurality of semiconductor chips CP after the cutting step (step (P2)). This step is sometimes referred to as the 4th adhesive sheet pasting step. The 4th adhesive sheet 40 has a 4th substrate 41 and a 4th adhesive layer 42. The material of the 4th substrate 41 is not particularly limited. Examples of materials for the fourth substrate 41 include polyvinyl chloride resin, polyester resin (polyethylene terephthalate, etc.), acrylic resin, polycarbonate resin, polyethylene resin, polypropylene resin, acrylonitrile butadiene styrene resin, polyimide resin, polyurethane resin, and polystyrene resin. The adhesive contained in the fourth adhesive layer 42 is not particularly limited. Examples of adhesives contained in the fourth adhesive layer 42 include rubber, acrylic, silicone, polyester, and urethane. In addition, the type of adhesive is selected in consideration of the use and the type of adherend to be adhered. The fourth adhesive sheet 40 may also be attached to the second annular frame together with the plurality of semiconductor chips CP. In this case, the second annular frame is placed on the fourth adhesive layer 42 of the fourth adhesive sheet 40, and is lightly pressed and fixed. Then, the fourth adhesive layer 42 exposed inside the annular shape of the second annular frame is pressed against the electrical path W1 of the semiconductor chip CP, and the plurality of semiconductor chips CP are fixed to the fourth adhesive sheet 40.

[Step of peeling off the first substrate] Figure 8B is a diagram showing a step of peeling off the first substrate 11 of the first adhesive sheet 10 after the fourth adhesive sheet 40 is attached. In this embodiment, the first substrate 11 is peeled off while the first adhesive layer 12 remains on the back surface W3 of the semiconductor chip CP. As one aspect of the first adhesive sheet 10, when the first adhesive layer 12 is directly laminated on the first substrate 11, in the step of peeling off the first substrate, it is preferred to peel off the interface between the first adhesive layer 12 and the first substrate 11. When the first substrate 11 is peeled off, a plurality of semiconductor chips CP with the first adhesive layer 12 attached to the back surface W3 are obtained. In addition, in the peeling step of the first substrate of the present embodiment, the first adhesive layer 12 that is not attached to the back surface W3 of the semiconductor chip CP is removed in a state of being attached to the first substrate 11 as shown in FIG. 8B .

[Step of pasting the second thin film] Figure 8C is a diagram for explaining step (P4). Figure 8C shows a state where the second thin film 20 is pasted to the plurality of semiconductor chips CP obtained by the cutting step. The second thin film 20 of this embodiment can use the same thin film as the second thin film 20 described in the first embodiment. In one aspect of the present invention, the second thin film 20 of this embodiment can be replaced with the same thin film as the second thin film 20A described in the second embodiment. In this embodiment, when the second thin film 20 is pasted to the back side W3 of the plurality of semiconductor chips CP, a laminated structure of the plurality of semiconductor chips CP and the second adhesive layer 22 of the second thin film 20 with the first adhesive layer 12 singulated therebetween is obtained.

[Step of peeling off the fourth adhesive sheet] After the step of sticking the second sheet 20, the fourth adhesive sheet 40 is peeled off from the conductive surface W1. This step is sometimes referred to as the step of peeling off the fourth adhesive sheet. The fourth adhesive layer 42 preferably contains an energy ray polymerizable compound. When the energy ray polymerizable compound is contained in the fourth adhesive layer 42, the fourth adhesive layer 42 is irradiated with energy rays from the fourth substrate 41 side to cure the energy ray polymerizable compound. When the energy ray polymerizable compound is cured, the cohesive force of the fourth adhesive layer 42 is increased, and the adhesive force between the fourth adhesive layer 42 and the semiconductor chip CP can be reduced or eliminated. Therefore, the fourth adhesive sheet 40 is easily peeled off. As energy rays, for example, ultraviolet rays (UV) or electron beams (EB) are exemplified, and ultraviolet rays are preferred. When the fourth adhesive sheet 40 is peeled off, a plurality of semiconductor chips CP supported by the second sheet 20 are obtained, so it is preferred to perform the same expansion step as the first embodiment. Regarding the expansion method of the fourth embodiment and the method for manufacturing a semiconductor device including the expansion method, other aspects can be performed in the same manner as the first embodiment.

[Effects of the present embodiment] By using the extended method of the present embodiment, as in the first embodiment, the tape structure and process can be simplified and the residual smear can be suppressed compared to the past. Furthermore, a method for manufacturing a semiconductor device including the extended method of the present embodiment can be provided. In addition, according to the present embodiment, a plurality of semiconductor chips CP can be peeled off the first substrate 11 while being supported by the fourth adhesive sheet 40. Therefore, the first substrate 11 can be easily peeled off, and the plurality of semiconductor chips CP can be prevented from scattering.

[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 package is taken 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 above-mentioned FO-WLP manufacturing method can also change some steps, and can also omit some steps. In one embodiment, the first adhesive sheet is a sheet in which the first substrate and the first adhesive layer are directly laminated as in the above-mentioned embodiment. In another embodiment, the first adhesive sheet is a sheet having an intermediate adhesive layer between the first substrate and the first adhesive layer, but the present invention is not limited to such embodiments. For example, the first adhesive sheet may also be a sheet having a peeling layer between the first substrate and the first adhesive layer. The peeling layer is preferably made of the same material as the peeling sheet in the description of the first embodiment.

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, the semiconductor wafer can also be completely separated and singulated into a plurality of semiconductor chips. In these methods, the irradiation of laser light can also be performed from any side of the semiconductor wafer. In the first embodiment, the example of pasting the first adhesive sheet 10 on the back surface W3 as the second wafer surface to implement the expansion method and the manufacturing method of the semiconductor device including the expansion method is listed for explanation, but the present invention is not limited to such aspects. For example, the first adhesive sheet 10 can also be pasted on the electrical surface W1 as the first wafer surface, and the expansion method and the manufacturing method of the semiconductor device including the expansion method can be implemented in the same way as the above-mentioned embodiment. Embodiment

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 is applied to a polyethylene terephthalate (PET) release film (manufactured by LINTEC Co., Ltd., product name "SP-PET381031", thickness 38μm) and dried to form a 40μm thick adhesive layer on the release film. In this embodiment, the adhesive layer is referred to as the second adhesive layer in accordance with the description in the aforementioned embodiment. After the second adhesive layer is 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 is cut off to produce an adhesive sheet SA1. Regarding the substrate, in this embodiment, it is referred to as the second substrate, corresponding to the description in the aforementioned embodiment.

(Method for measuring chip spacing) The adhesive sheet SA1 obtained in Example 1 is cut into 210 mm × 210 mm sheets to obtain test sheets. At this time, the sheets are cut so that the sides of the sheets are parallel or perpendicular to the MD direction of the second substrate of the adhesive sheet. The semiconductor chip to be attached to the adhesive sheet is prepared in the following sequence. The first adhesive sheet (manufactured by LINTEC Co., Ltd., product name "LC2850 (25)") is attached to a 6-inch silicon wafer. Since the first adhesive sheet (LC2850 (25)) is a thermosetting type, after the first adhesive sheet is attached to the silicon wafer, it is heated to cure the first adhesive layer of the first adhesive sheet to obtain a cured film. Next, the 6-inch silicon wafer and the hardened film are cut from the side so that the 3mm×3mm chips are arranged in 5 rows in the X-axis direction and 5 rows in the Y-axis direction, and a total of 25 chips are cut out. The cut hardened film is pasted on each chip. The peeling film of the peeling test sheet is pasted on the hardened film side of the 25 chips cut out as described above at the center of the exposed second 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 (separation device). FIG. 9 shows a top view of the expansion device 100. In FIG9 , the X-axis and the Y-axis are orthogonal to each other, the positive direction of the X-axis is set as the +X-axis direction, the negative direction of the X-axis is set as the -X-axis direction, the positive direction of the Y-axis is set as the +Y-axis direction, and the negative direction of the Y-axis is set as the -Y-axis direction. The test sheet 200 is set in the expansion device 100 in 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 FIG9 .

As shown in FIG9 , 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 FIG9 , 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 vertex 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 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 10 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 in the same way. 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 ultraviolet rays from the surface of the adhesive sheet of Example 1 opposite to the surface on which the chip is mounted at an illumination of 220mW/ ^cm2 and a light quantity of 460mJ/ ^cm2 . After ultraviolet irradiation, the chip is held by an adsorption table and the adhesive sheet is peeled off. After peeling off the adhesive sheet, the surface of the cured film of the chip with the adhesive sheet attached is observed under an optical microscope. If no residual blur is observed on the surface of the cured film of the chip, it is judged as acceptable "A", and if residual blur is observed, it is judged as unacceptable "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 first adhesive layer (cured film) was interposed between the chip and the adhesive sheet of Example and the adhesive sheet was expanded, the evaluation result of the residual paste on the surface of the cured film of the chip was judged as qualified "A".

3: Sealing body 3A: Surface 10,10A: 1st adhesive sheet 11: 1st substrate 12: 1st adhesive layer 13: Intermediate adhesive layer 20,20A: 2nd sheet 21,21A: 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 100: Extension Device 101, 101A, 101B, 101C: Holding mechanism 200: Test sheet 300: Sealing member W: Semiconductor wafer W1: Surface of the circuit W2: Circuit W3: Back 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 and bottom 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. 5] is a cross-sectional view illustrating the manufacturing method of the second embodiment. [FIG. 6] 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 third embodiment. [FIG. 7B] is a cross-sectional view illustrating the manufacturing method of the third embodiment. [FIG. 7C] is a cross-sectional view illustrating the manufacturing method of the third embodiment. [FIG. 8A] is a cross-sectional view illustrating the manufacturing method of the fourth embodiment. [FIG. 8B] is a cross-sectional view illustrating the manufacturing method of the fourth embodiment. [FIG. 8C] is a cross-sectional view illustrating the manufacturing method of the fourth embodiment. [FIG. 9] is a top view illustrating the biaxial extension device used in the embodiment. [FIG. 10] is a schematic view for illustrating the method of measuring the chip arrangement.

12: 1st adhesive layer

20: 2nd slice

21: Second base material

22: Second adhesive layer

W1: Electric road surface

W2: Circuit

W3: Back

CP: semiconductor chip

Claims (12)

An expansion method is provided, wherein a first adhesive sheet having a first adhesive layer and a first substrate is attached to the second wafer surface of a wafer having a first wafer surface and a second wafer surface on the opposite side of the first wafer surface, a cut is made from the first wafer surface side, the wafer is singulated into a plurality of chips, the first adhesive layer is further cut, the first substrate is peeled off from the first adhesive layer at the interface between the first adhesive layer and the first substrate with the first adhesive layer remaining on the second wafer surface, a second sheet is attached to the first adhesive layer, the second sheet is stretched, and the interval between the plurality of chips is expanded. As in the expansion method of claim 1, wherein the aforementioned cut is formed to a depth reaching the aforementioned first substrate. As in the expansion method of claim 1, wherein the first adhesive layer contains a first energy ray-curable resin. As in the expansion method of claim 1, wherein the aforementioned second sheet is an expansion sheet. As in the expansion method of claim 1, the second sheet has a second adhesive layer and a second substrate, and the second adhesive layer contains a second energy ray-curable resin. As in the expansion method of claim 1, the peeling force of the first substrate when peeling off from the first adhesive layer is greater than 10mN/25mm and less than 2000mN/25mm. As in the expansion method of claim 1, the first adhesive sheet is directly laminated with the first adhesive layer on the first substrate, and the second wafer surface is attached to the first adhesive layer facing the first adhesive sheet. As in the expansion method of claim 1, after the first adhesive layer is peeled off from the first substrate, the plurality of chips to which the first adhesive layer is adhered are held by a holding member, and the second sheet is attached to the first adhesive layer before being adhered to the plurality of chips held by the holding member. As in the expansion method of claim 1, after singulating the wafer into a plurality of chips, the first adhesive sheet is stretched to expand the interval between the plurality of chips. 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 10, 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 11.

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