EXPANSION METHOD AND SEMICONDUCTOR DEVICE MANUFACTURING METHOD

Abstract

An expanding method comprising the step of stretching a first sheet (10) to which a plurality of semiconductor devices (CPs) are attached, thereby increasing the spacing between the plurality of semiconductor devices (CPs), wherein each of the plurality of semiconductor devices (CPs) has a first semiconductor device face (W1) and a second semiconductor device face (W3) opposite the first semiconductor device face (W1), and each of the plurality of semiconductor devices (CPs) is attached with a protective layer (100) between the second semiconductor device face (W3) and the first sheet (10).

Description

[Technical field]

[0001] The present invention relates to an expanding method and a method for manufacturing a semiconductor device. [Background technology]

[0002] In recent years, electronic devices have become smaller, lighter, and more functional. Semiconductor devices mounted on electronic devices are also required to be smaller, thinner, and more dense. A semiconductor chip may be mounted in a package close to the size of the chip. Such a package may be called a chip scale package (CSP). One type of CSP is a wafer level package (WLP). In a WLP, external electrodes and the like are formed on a wafer before the wafer is diced into individual pieces, and the wafer is finally diced into individual pieces. WLPs include a fan-in type and a fan-out type. In a fan-out type WLP (hereinafter sometimes abbreviated as "FO-WLP"), a semiconductor chip is covered with an encapsulating material so that the area is larger than the chip size to form a semiconductor chip encapsulation body, and a rewiring layer and external electrodes are formed not only on the circuit surface of the semiconductor chip but also on the surface area of ​​the encapsulating material.

[0003] For example, Patent Document 1 describes a method for manufacturing a semiconductor package in which a plurality of semiconductor chips separated from a semiconductor wafer are surrounded by a molding member while leaving the circuit formation surface, forming an extended wafer, and a rewiring pattern is extended to an area outside the semiconductor chip. In the manufacturing method described in Patent Document 1, before surrounding the plurality of separated semiconductor chips with the molding member, the plurality of semiconductor chips are replaced with an expanding wafer mount tape, and the wafer mount tape is expanded to expand the distance between the plurality of semiconductor chips.

[0004] Patent Document 2 also describes a pressure-sensitive adhesive sheet comprising a second base layer, a first base layer, and a first adhesive layer in this order, where the second base layer has a breaking elongation of 400% or more. The method for manufacturing a semiconductor device described in Patent Document 2 includes a step of attaching a semiconductor wafer to the first adhesive layer of the pressure-sensitive adhesive sheet, a step of dicing the semiconductor wafer to form multiple semiconductor chips, and a step of stretching the pressure-sensitive adhesive sheet to increase the distance between the semiconductor chips. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2010 / 058646 [Patent Document 2] JP 2017-076748 A Summary of the Invention [Problem to be solved by the invention]

[0006] The tape used in the expanding process usually has an adhesive layer for fixing the semiconductor chip on the tape and a base material for supporting the adhesive layer. When the wafer mount tape for expanding is stretched as described in Patent Document 1, not only the base material of the tape but also the adhesive layer is stretched. After the expanding process, when the semiconductor chip is peeled off from the adhesive layer, a defect may occur in which the adhesive layer remains on the surface of the semiconductor chip that was in contact with the adhesive layer. In this specification, such a defect may be referred to as adhesive residue. In addition, when the expanding step is performed using the adhesive sheet described in Patent Document 2, the adhesive layer in contact with the semiconductor chip is not stretched, so it is considered that adhesive residue is unlikely to occur. However, since the adhesive sheet described in Patent Document 2 has a tape configuration in which a second base material layer, a first base material layer, and a first adhesive layer are laminated, there is a demand for an expanding method that can prevent adhesive residue using a simpler tape configuration. In addition, in the process described in Patent Document 2, the semiconductor wafer on the adhesive sheet is diced, and the adhesive sheet is stretched as it is without transferring it to another adhesive sheet to perform the expanding step. Therefore, it is necessary to carefully control the cutting depth of the dicing blade so that the dicing blade does not reach the second base material layer during dicing, and there is also a demand for an expanding method that can prevent adhesive residue by a simpler method. In the expanding method, the adherend supported on the pressure-sensitive adhesive sheet may be not only a semiconductor chip, but also, for example, a semiconductor device such as a wafer, a semiconductor device package, and a micro LED. As with semiconductor chips, the spacing between these semiconductor devices may be expanded.

[0007] The object of the present invention is to provide an expanding method that can simplify at least one of the tape configuration and the process compared to conventional methods while suppressing glue residue, and to provide a manufacturing method for a semiconductor device that includes the expanding method. [Means for solving the problem]

[0008] According to one aspect of the present invention, there is provided an expanding method including a step of stretching a first sheet to which a plurality of semiconductor devices are attached to increase the spacing between the plurality of semiconductor devices, each of the plurality of semiconductor devices having a first semiconductor device surface and a second semiconductor device surface opposite the first semiconductor device surface, and each of the plurality of semiconductor devices being attached to the first sheet including a protective layer between the first semiconductor device surface or the second semiconductor device surface and the first sheet.

[0009] In the expanding method according to one aspect of the present invention, it is preferable that after the protective layer is formed on the first semiconductor device surface, the plurality of semiconductor devices are attached to the first sheet.

[0010] In the expanding method according to one aspect of the present invention, it is preferable that the plurality of semiconductor devices are obtained by dicing an object to be processed.

[0011] In the expanding method according to one aspect of the present invention, it is preferable that the protective layer is formed on the object to be processed, and the plurality of semiconductor devices are obtained by dicing the object to be processed and the protective layer.

[0012] In an expanding method according to one embodiment of the present invention, it is preferable to attach the object to be processed on which the protective layer is formed to a second adhesive layer of a second adhesive sheet having a second adhesive layer and a second base material, dicing the protective layer and the object to be processed to obtain the multiple semiconductor devices, and attaching the first sheet to the protective layer after dicing.

[0013] In the expanding method according to one aspect of the present invention, it is preferable that the second adhesive sheet is peeled off after the first sheet is attached to the protective layer after dicing.

[0014] In an expanding method according to one embodiment of the present invention, it is preferable to attach the object to be processed to the protective layer of a composite sheet having the protective layer and a third sheet, dicing the object to be processed and the protective layer to obtain the multiple semiconductor devices, and peeling the third sheet from the protective layer.

[0015] In an expanding method according to one embodiment of the present invention, it is preferable that the protective layer and the first sheet are laminated in advance, the object to be processed is supported by the protective layer, and the object to be processed and the protective layer are diced to obtain the multiple semiconductor devices.

[0016] In the expanding method according to one aspect of the present invention, the object to be processed is preferably a semiconductor wafer.

[0017] In the expanding method according to one aspect of the present invention, the first sheet is preferably an expanding sheet.

[0018] In the expanding method according to one aspect of the present invention, the first semiconductor device surface preferably has a circuit.

[0019] According to one aspect of the present invention, there is provided a method for manufacturing a semiconductor device, the method including the expanding method according to the above-mentioned aspect of the present invention.

[0020] According to one aspect of the present invention, there is provided an expanding method that can simplify at least one of the tape configuration and the process compared to the conventional method and suppress adhesive residue. According to another aspect of the present invention, there is provided a manufacturing method of a semiconductor device including the expanding method. [Brief description of the drawings]

[0021] [Figure 1A] 1A to 1C are cross-sectional views illustrating a manufacturing method according to a first embodiment. [Figure 1B] 1A to 1C are cross-sectional views illustrating a manufacturing method according to a first embodiment. [Figure 1C] 1A to 1C are cross-sectional views illustrating a manufacturing method according to a first embodiment. [Figure 2A] 1A to 1C are cross-sectional views illustrating a manufacturing method according to a first embodiment. [Figure 2B] 1A to 1C are cross-sectional views illustrating a manufacturing method according to a first embodiment. [Diagram 3] 1A to 1C are cross-sectional views illustrating a manufacturing method according to a first embodiment. [Figure 4A] 1A to 1C are cross-sectional views illustrating a manufacturing method according to a first embodiment. [Figure 4B] 1A to 1C are cross-sectional views illustrating a manufacturing method according to a first embodiment. [Figure 5A] 1A to 1C are cross-sectional views illustrating a manufacturing method according to a first embodiment. [Figure 5B]1A to 1C are cross-sectional views illustrating a manufacturing method according to a first embodiment. [Figure 6A] 11A to 11C are cross-sectional views illustrating a manufacturing method according to a second embodiment. [Figure 6B] 11A to 11C are cross-sectional views illustrating a manufacturing method according to a second embodiment. [Figure 6C] 11A to 11C are cross-sectional views illustrating a manufacturing method according to a second embodiment. [Figure 7A] 11A to 11C are cross-sectional views illustrating a manufacturing method according to a second embodiment. [Figure 7B] 11A to 11C are cross-sectional views illustrating a manufacturing method according to a second embodiment. [Figure 7C] 11A to 11C are cross-sectional views illustrating a manufacturing method according to a second embodiment. [Figure 8A] 13A to 13C are cross-sectional views illustrating a manufacturing method according to a third embodiment. [Figure 8B] 13A to 13C are cross-sectional views illustrating a manufacturing method according to a third embodiment. [Figure 8C] 13A to 13C are cross-sectional views illustrating a manufacturing method according to a third embodiment. [Figure 9] 13A to 13C are cross-sectional views illustrating a manufacturing method according to a third embodiment. [Figure 10] FIG. 2 is a plan view illustrating a biaxial stretching and expanding device used in the examples. [Figure 11] FIG. 1 is a schematic diagram for explaining a method for measuring chip alignment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] [First embodiment] The expanding method according to this embodiment and the manufacturing method of a semiconductor device including the expanding method will be described below.

[0023] Figures 1 (Figures 1A, 1B, and 1C), 2 (Figures 2A and 2B), 3, 4 (Figures 4A and 4B), and 5 (Figures 5A and 5B) are cross-sectional schematic views illustrating a manufacturing method for a semiconductor device including an expansion method according to this embodiment.

[0024] The expanding method according to this embodiment includes at least the following steps (P1) and (P2). (P1) A step of preparing a plurality of semiconductor devices attached to a first sheet, the plurality of semiconductor devices being attached with a protective layer between the first sheet and the semiconductor devices. (P2) A process of expanding the first sheet to increase the spacing between the multiple semiconductor devices.

[0025] 1A, 1B, 1C, 2A and 2B are views for explaining the step (P1).

[0026] (Item to be processed) FIG. 1A shows a schematic cross-sectional view of a workpiece having a protective layer. In this embodiment, the workpiece will be described by taking a semiconductor wafer W as an example. In the present invention, the workpiece is not limited to a wafer. The semiconductor wafer W has a circuit surface W1 as a first processing surface and a back surface W3 as a second processing surface. A circuit W2 is formed on the circuit surface W1. In this embodiment, a protective layer 100 is provided on the circuit surface W1.

[0027] The semiconductor wafer W may be, for example, a silicon wafer or a compound semiconductor wafer such as gallium arsenide. Methods for forming the circuit W2 on the circuit surface W1 of the semiconductor wafer W include commonly used methods, such as an etching method and a lift-off method.

[0028] (protective layer) The protective layer 100 is a layer that covers the circuit surface W1 and the circuit W2. The protective layer 100 is not particularly limited as long as it can protect the circuit surface W1 and the circuit W2. The thickness of the protective layer 100 is preferably 1 μm or more, and more preferably 5 μm or more. The thickness of the protective layer 100 is preferably 500 μm or less, and more preferably 300 μm or less.

[0029] Examples of the protective layer 100 include a protective film and a protective sheet. The protective film is preferably a film obtained by, for example, depositing a resin material on the circuit surface W1. The protective film may have one layer or two or more layers. Examples of the deposition method include a printing method, a spray coating method, a spin coating method, and a dipping method. The protective sheet may be, for example, a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer and a substrate. The substrate in the protective sheet may be any material that can function appropriately as one of the members constituting the protective layer and can support the pressure-sensitive adhesive layer. The substrate in the protective sheet is preferably made of a film mainly made of a resin-based material. Examples of films mainly made of a resin-based material include ethylene copolymer films, polyolefin films, polyvinyl chloride films, polyester films, polyurethane films, polyimide films, polystyrene films, polycarbonate films, and fluororesin films. The adhesive layer in the protective sheet is not particularly limited in terms of its constituent material, so long as it functions appropriately as one of the members constituting the protective layer and can adhere to the substrate and the circuit surface W1. The adhesive layer in the protective sheet 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 an acrylic adhesive.

[0030] In the description of this embodiment, the protective layer 100 is a protective film made up of one layer, but the present invention is not limited to this embodiment.

[0031] [Back grinding process] The semiconductor wafer W is preferably a wafer obtained by a back-grinding process. The step (P1) of preparing a plurality of semiconductor devices attached to a first sheet preferably includes this back-grinding process as a step (P1-1). In the back grinding process, the surface of the semiconductor wafer W opposite to the circuit surface W1 is ground to a predetermined thickness. The back surface W3 is preferably a surface formed by back grinding the semiconductor wafer W. The surface exposed after grinding the semiconductor wafer W is referred to as the back surface W3.

[0032] The method for grinding the semiconductor wafer W is not particularly limited, and examples thereof include known methods using a grinder or the like. When grinding the semiconductor wafer W, it is preferable to attach an adhesive sheet called a backgrind sheet to the circuit surface W1 in order to protect the circuit W2. In grinding the back surface of the wafer, the circuit surface W1 side of the semiconductor wafer W, i.e., the backgrind sheet side, is fixed by a chuck table or the like, and the back surface side on which no circuit is formed is ground by a grinder. The process of attaching the backgrind sheet to the circuit surface W1 is sometimes referred to as the backgrind sheet attachment process.

[0033] The thickness of the semiconductor wafer W before grinding is not particularly limited, and is usually 500 μm or more and 1000 μm or less. The thickness of the semiconductor wafer W after grinding is not particularly limited, and is usually 20 μm or more and 500 μm or less.

[0034] [Second adhesive sheet attachment process] FIG. 1B shows a semiconductor wafer W having a second adhesive sheet 20 attached to its back surface W3. The semiconductor wafer W prepared in step (P1) is preferably a wafer obtained through a back grinding step and a bonding step of bonding a second adhesive sheet 20 to the back surface W3. This bonding step may be referred to as a second adhesive sheet bonding step. As described later, in step (P2), the semiconductor wafer W is divided into a plurality of semiconductor chips CP by dicing. When dicing the semiconductor wafer W, it is preferable to attach an adhesive sheet called a dicing sheet to the back surface W3 in order to hold the semiconductor wafer W. In this embodiment, it is preferable that the second adhesive sheet 20 is a dicing sheet. When the second adhesive sheet 20 is used as the dicing sheet, the semiconductor wafer W is attached with the back surface W3 facing the second adhesive layer 22 of the second adhesive sheet 20. The circuit surface W1 of the semiconductor wafer W corresponds to the circuit surface W1 of the semiconductor chip CP. The back surface W3 of the semiconductor wafer W corresponds to the back surface W3 of the semiconductor chip CP.

[0035] [Dicing process] Fig. 1C is a diagram for explaining a dicing step of dicing a semiconductor wafer W as a processing object. Fig. 1C shows a plurality of semiconductor chips CP held by a second adhesive sheet 20. In this embodiment, the semiconductor chips CP are described as an example of a semiconductor device, but the present invention is not limited to such an embodiment. Examples of the semiconductor device include a wafer, a semiconductor device package, and a micro LED.

[0036] The multiple semiconductor devices prepared in step (P1) are preferably multiple semiconductor chips CP obtained in a dicing step by dicing the semiconductor wafer W. The step (P1) preferably includes a dicing step of dicing the semiconductor wafer W supported by the second adhesive sheet 20 as step (P1-2). The semiconductor wafer W with the protective layer 100 provided on the circuit surface W1 and the second adhesive sheet 20 attached to the back surface W3 is diced into individual pieces to form a plurality of semiconductor chips CP. In this embodiment, an incision is made from the protective layer 100 side to cut the protective layer 100, and the semiconductor wafer W is further cut. After the dicing process, the circuit surfaces W1 of the plurality of semiconductor chips CP are each covered with the cut protective layer 100. For the dicing, a cutting means such as a dicing saw is used. The cutting depth during dicing is not particularly limited as long as it is a depth that can separate the protective layer 100 and the semiconductor wafer W. From the viewpoint of reliably cutting the semiconductor wafer W, the incisions in the dicing process are preferably formed to a depth that reaches the second adhesive sheet 20 from the protective layer 100 side, and more preferably to a depth that reaches the second adhesive layer 22 of the second adhesive sheet 20. By dicing, the second adhesive layer 22 is also cut to the same size as the semiconductor chips CP. Furthermore, by dicing, incisions may also be formed in the second base material 21.

[0037] [First sheet attachment process] FIG. 2A is a diagram for explaining a step of attaching a first sheet 10 to a plurality of semiconductor chips CP after a dicing step. FIG. 2A shows a state in which the first sheet 10 is attached to a plurality of semiconductor chips CP obtained by a dicing step. The first sheet 10 according to this embodiment is an adhesive sheet having a first adhesive layer 12 and a first base material 11. Details of the first sheet 10 will be described later. Note that in the present invention, the first sheet is not limited to an adhesive sheet having a two-layer structure having a first adhesive layer and a first base material.

[0038] In this embodiment, when the first sheet 10 is attached to the circuit surface W1 side of the multiple semiconductor chips CP, a laminated structure is obtained in which individualized protective layers 100 are interposed between the multiple semiconductor chips CP and the first adhesive layer 12 of the first sheet 10.

[0039] [Second adhesive sheet peeling process] Fig. 2B is a diagram for explaining the step of peeling off the second adhesive sheet 20 after the step of attaching the first sheet. This step may be referred to as the step of peeling off the second adhesive sheet. Fig. 2B shows a state in which the second adhesive sheet 20 has been peeled off from the back surface W3 of the semiconductor wafer W after the first sheet 10 has been attached. After the first sheet 10 is attached, the second adhesive sheet 20 is peeled off to expose the rear surfaces W3 of the multiple semiconductor chips CP. In addition, when an energy ray-polymerizable compound is blended in the second adhesive layer 22, it is preferable to irradiate the second adhesive layer 22 with energy rays from the second substrate 21 side to harden the energy ray-polymerizable compound before peeling off the second adhesive sheet 20.

[0040] [Expanding process] Fig. 3 is a diagram for explaining step (P2). Step (P2) may be referred to as an expanding step. Fig. 3 shows a state in which the first sheet 10 is expanded after the second adhesive sheet 20 is peeled off, thereby expanding the intervals between the multiple semiconductor chips CP. When expanding the intervals between the multiple semiconductor chips CP, it is preferable to expand an adhesive sheet called an expand sheet while holding the multiple semiconductor chips CP. In this embodiment, it is preferable that the first sheet 10 is an expand sheet. The method of stretching the first sheet 10 in the expanding step is not particularly limited. Examples of the method of stretching the first sheet 10 include a method of pressing an annular or circular expander against the first sheet 10 to stretch it, and a method of gripping and stretching the outer periphery of the first sheet 10 using a gripping member or the like. In this embodiment, the interval D1 between the multiple semiconductor chips CP is not particularly limited because it depends on the size of the semiconductor chips CP. In particular, the interval D1 between adjacent semiconductor chips CP in the multiple semiconductor chips CP attached to one side of the adhesive sheet is preferably 200 μm or more. The upper limit of the interval between the semiconductor chips CP is not particularly limited. The upper limit of the interval between the semiconductor chips CP may be, for example, 6000 μm.

[0041] [First transfer process] In this embodiment, after the expanding process, a process (hereinafter sometimes referred to as the "first transfer process") may be carried out in which the multiple semiconductor chips CP attached to the first sheet 10 are transferred to another adhesive sheet (e.g., a fifth adhesive sheet). FIG. 4A shows a diagram for explaining the step of transferring a plurality of semiconductor chips CP, which have been attached to the first sheet 10, to a fifth adhesive sheet 50 (hereinafter sometimes referred to as the "transfer step"). The fifth adhesive sheet 50 is not particularly limited as long as it can hold a plurality of semiconductor chips CP. The fifth adhesive sheet 50 has a fifth base material 51 and a fifth adhesive layer 52. When the transfer step is performed in this embodiment, for example, it is preferable to attach a fifth adhesive sheet 50 to the rear surfaces W3 of the multiple semiconductor chips CP after the expanding step, and then peel off the first sheet 10.

[0042] The fifth adhesive sheet 50 may be attached to a second ring frame together with the plurality of semiconductor chips CP. In this case, the ring frame is placed on the fifth adhesive layer 52 of the fifth adhesive sheet 50, and is lightly pressed and fixed. Thereafter, the fifth adhesive layer 52 exposed on the inner side of the ring shape of the ring frame is pressed against the back surface W3 of the semiconductor chip CP, and the plurality of semiconductor chips CP are fixed to the fifth adhesive sheet 50.

[0043] FIG. 4B is a diagram illustrating the step of peeling off first sheet 10 after fifth adhesive sheet 50 has been attached. In this embodiment, a mode will be described in which, when peeling off the first sheet 10, the individualized first sheet 10 covering the circuit surface W1 of the semiconductor chip CP is peeled off together with the protective layer 100. Note that a mode in which only the first sheet 10 is peeled off may also be used, with the individualized protective layer 100 covering the circuit surface W1 remaining on the semiconductor chip CP. After the fifth adhesive sheet 50 is attached, the circuit surfaces W1 of the multiple semiconductor chips CP are exposed by peeling off the first sheet 10 and the protective layer 100. It is preferable that the intervals D1 between the multiple semiconductor chips CP expanded in the expanding step are maintained even after the first sheet 10 and the protective layer 100 are peeled off.

[0044] [Second transfer process] FIG. 5A shows a diagram for explaining a step of transferring a plurality of semiconductor chips CP, which have been attached to a fifth adhesive sheet 50, to a sixth adhesive sheet 60 (hereinafter, sometimes referred to as a "second transfer step"). It is preferable that the plurality of semiconductor chips CP transferred from the fifth adhesive sheet 50 to the sixth adhesive sheet 60 maintain the distance D1 between the semiconductor chips CP.

[0045] The sixth adhesive sheet 60 is not particularly limited as long as it can hold a plurality of semiconductor chips CP. The sixth adhesive sheet 60 has a sixth base material 61 and a sixth adhesive layer 62. When it is desired to seal a plurality of semiconductor chips CP on the sixth adhesive sheet 60, it is preferable to use an adhesive sheet for the sealing process, and it is more preferable to use a heat-resistant adhesive sheet, as the sixth adhesive sheet 60. Furthermore, when a heat-resistant adhesive sheet is used as the sixth adhesive sheet 60, it is preferable that the sixth base material 61 and the sixth adhesive layer 62 are each formed of a material having heat resistance capable of withstanding the temperature applied in the sealing process.

[0046] The semiconductor chips CP transferred from the fifth adhesive sheet 50 to the sixth adhesive sheet 60 are attached with their circuit surfaces W1 facing the sixth adhesive layer 62.

[0047] [Sealing process] FIG. 5B shows a diagram for explaining a process of sealing a plurality of semiconductor chips CP with sealing member 300 (hereinafter, sometimes referred to as an "encapsulating process").

[0048] In this embodiment, the sealing step is performed after the multiple semiconductor chips CP are transferred to the sixth adhesive sheet 60. In the sealing process, the sealing body 3 is formed by covering the semiconductor chips CP with the sealing member 300 while the circuit surface W1 is protected by the sixth adhesive sheet 60. The sealing member 300 is also filled between the semiconductor chips CP. Since the circuit surface W1 and the circuit W2 are covered by the sixth adhesive sheet 60, it is possible to prevent the circuit surface W1 from being covered by the sealing member 300.

[0049] The sealing step provides a sealing body 3 in which a plurality of semiconductor chips CP spaced apart from each other by a predetermined distance are embedded in the sealing member 300. In the sealing step, the plurality of semiconductor chips CP are preferably covered by the sealing member 300 while maintaining the intervals D1 after the expanding step is performed.

[0050] After the sealing step, the sixth adhesive sheet 60 is peeled off. When the sixth adhesive sheet 60 is peeled off, the circuit surface W1 of the semiconductor chip CP and the surface 3A of the sealing body 3 that was in contact with the sixth adhesive sheet 60 are exposed.

[0051] After the aforementioned expanding process, the transfer process and the expanding process can be repeated any number of times to set the distance between the semiconductor chips CP to a desired distance and to set the orientation of the circuit surface when sealing the semiconductor chips CP to a desired orientation.

[0052] [Other processes] After the adhesive sheet is peeled off from the sealing body 3, a rewiring layer forming process for forming a rewiring layer electrically connected to the semiconductor chip CP and a connecting process for electrically connecting the rewiring layer and the external terminal electrodes are sequentially performed on the sealing body 3. The rewiring layer forming process and the connecting process with the external terminal electrodes electrically connect the circuit of the semiconductor chip CP to the external terminal electrodes. The sealing body 3 to which the external terminal electrodes are connected is diced into individual semiconductor chips CP. The method for dicing the sealing body 3 is not particularly limited. By dicing the sealing body 3, semiconductor packages are manufactured in units of semiconductor chips CP. The semiconductor packages to which the external electrodes fanned out to the outside of the region of the semiconductor chip CP are connected are manufactured as fan-out type wafer level packages (FO-WLP).

[0053] (1st sheet) The first sheet 10 according to this embodiment has a first base material 11 and a first pressure-sensitive adhesive layer 12. The first pressure-sensitive adhesive layer 12 is laminated on the first base material 11.

[0054] ·First base material The material constituting the first base material 11 is not particularly limited as long as it can function appropriately in a desired step such as the expanding step (for example, step (P2)). The first substrate 11 has a first substrate front surface and a first substrate back surface. The first substrate back surface is the surface opposite to the first substrate front surface. In the first sheet 10, a first pressure-sensitive adhesive layer 12 is preferably provided on one of the front surface and the back surface of the first substrate, and it is preferable that no pressure-sensitive adhesive layer is provided on the other surface.

[0055] From the viewpoint of ease of being largely stretched, the material of the first base material 11 is preferably a thermoplastic elastomer or a rubber-based material, and more preferably a thermoplastic elastomer.

[0056] From the viewpoint of ease of large stretching, it is preferable to use a resin having a relatively low glass transition temperature (Tg) as the material for the first base material 11. The glass transition temperature (Tg) of such a resin is preferably 90° C. or lower, more preferably 80° C. or lower, and further preferably 70° C. or lower.

[0057] Examples of the thermoplastic elastomer include urethane-based elastomers, olefin-based elastomers, vinyl chloride-based elastomers, polyester-based elastomers, styrene-based elastomers, acrylic-based elastomers, and amide-based elastomers. The thermoplastic elastomers can be used alone or in combination of two or more. As the thermoplastic elastomer, it is preferable to use a urethane-based elastomer, from the viewpoint of being easily stretched to a large extent.

[0058] Urethane elastomers are generally obtained by reacting a long-chain polyol, a chain extender, and a diisocyanate, and are composed of a soft segment having a structural unit derived from the long-chain polyol and a hard segment having a polyurethane structure obtained by reacting a chain extender with a diisocyanate.

[0059] When classified according to the type of long-chain polyol, urethane-based elastomers are divided into polyester-based polyurethane elastomers, polyether-based polyurethane elastomers, polycarbonate-based polyurethane elastomers, etc. The urethane-based elastomers can be used alone or in combination of two or more. In this embodiment, the urethane-based elastomer is preferably a polyether-based polyurethane elastomer from the viewpoint of being easily stretched to a large extent.

[0060] Examples of long-chain polyols include polyester polyols such as lactone-based polyester polyols and adipate-based 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-based polyester polyol from the viewpoint of being easily stretched.

[0061] Examples of diisocyanates include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, etc. In the present embodiment, the diisocyanate is preferably hexamethylene diisocyanate from the viewpoint of ease of being greatly stretched.

[0062] Examples of the chain extender include low molecular weight polyhydric alcohols (e.g., 1,4-butanediol, 1,6-hexanediol, etc.), aromatic diamines, etc. Among these, it is preferable to use 1,6-hexanediol from the viewpoint of ease of large extension.

[0063] Examples of the olefin-based elastomer include elastomers 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-butylene copolymers. The olefin-based elastomers may be used alone or in combination of two or more.

[0064] The density of the olefin-based elastomer is not particularly limited. For example, the density of the olefin-based elastomer is 0.860 g / cm 3 More than 0.905g / cm 3 Preferably, it is less than 0.862 g / cm 3 More than 0.900g / cm 3 More preferably, it is less than 0.864 g / cm 3 More than 0.895g / cm 3 When the density of the olefin-based elastomer satisfies the above range, the substrate has excellent conformability to irregularities when a semiconductor device as an adherend is attached to the pressure-sensitive adhesive sheet.

[0065] It is preferable that the mass ratio of monomers consisting of olefin compounds (also referred to as "olefin content" in this specification) among all monomers used to form the olefin elastomer is 50 mass% or more and 100 mass% or less. If the olefin content is too low, the properties of an elastomer containing structural units derived from an olefin are less likely to be exhibited, and the substrate is less likely to exhibit flexibility and rubber elasticity. From the viewpoint of stably obtaining flexibility and rubber elasticity, the olefin content is preferably 50% by mass or more, and more preferably 60% by mass or more.

[0066] Examples of the styrene-based elastomer include styrene-conjugated diene copolymers, styrene-olefin copolymers, etc. Specific examples of the styrene-conjugated diene copolymers include unhydrogenated styrene-conjugated diene copolymers such as styrene-butadiene copolymer, styrene-butadiene-styrene copolymer (SBS), styrene-butadiene-butylene-styrene copolymer, styrene-isoprene copolymer, styrene-isoprene-styrene copolymer (SIS), and styrene-ethylene-isoprene-styrene copolymer, and hydrogenated styrene-conjugated diene copolymers such as styrene-ethylene / propylene-styrene copolymer (SEPS, a water-added product of styrene-isoprene-styrene copolymer), and styrene-ethylene-butylene-styrene copolymer (SEBS, a hydrogenated product of styrene-butadiene copolymer). In addition, examples of industrially usable styrene-based elastomers include trade names such as Tufprene (manufactured by Asahi Kasei Corporation), Kraton (manufactured by Kraton Polymer Japan Co., Ltd.), Sumitomo TPE-SB (manufactured by Sumitomo Chemical Co., Ltd.), Epofriend (manufactured by Daicel Corporation), Rabalon (manufactured by Mitsubishi Chemical Corporation), Septon (manufactured by Kuraray Co., Ltd.), and Tuftec (manufactured by Asahi Kasei Corporation). The styrene-based elastomer may be hydrogenated or unhydrogenated.

[0067] Examples of rubber-based 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, polysulfide rubber, etc. The rubber-based materials may be used alone or in combination of two or more.

[0068] The first base material 11 may be a laminated film in which a plurality of films made of the above-mentioned materials (for example, thermoplastic elastomer or rubber-based material) are laminated. The first base material 11 may also be a laminated film in which a film made of the above-mentioned materials (for example, thermoplastic elastomer or rubber-based material) is laminated with another film.

[0069] The first substrate 11 may contain additives in a film mainly made of the above-mentioned resin-based material. Specific examples of additives are the same as those listed in the description 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 additives that may be contained in the film is not particularly limited, but is preferably within a range in which the first substrate 11 can exhibit the desired function.

[0070] One or both sides of first substrate 11 may be subjected to a treatment for improving adhesion to first pressure-sensitive adhesive layer 12 laminated on the surface of first substrate 11.

[0071] When the first adhesive layer 12 contains an energy ray-curable adhesive, the first substrate 11 is preferably transparent to energy rays. When ultraviolet rays are used as the energy rays, the first substrate 11 is preferably transparent to ultraviolet rays. When electron beams are used as the energy rays, the first substrate 11 is preferably transparent to electron beams.

[0072] The thickness of the first substrate 11 is not limited as long as the first sheet 10 can function appropriately in the desired process. The thickness of the first substrate 11 is preferably 20 μm or more, and more preferably 40 μm or more. The thickness of the first substrate 11 is preferably 250 μm or less, and more preferably 200 μm or less.

[0073] Furthermore, when the thickness of first substrate 11 is measured at multiple locations at 2 cm intervals in the in-plane direction of the first substrate front surface or the first substrate back surface, the standard deviation of the thickness of first substrate 11 is preferably 2 μm or less, more preferably 1.5 μm or less, and even more preferably 1 μm or less. With the standard deviation of 2 μm or less, first sheet 10 has a highly accurate thickness, and first sheet 10 can be stretched uniformly.

[0074] It is preferable that the tensile modulus of elasticity in the MD and CD directions of the first substrate 11 at 23°C is 10 MPa or more and 350 MPa or less, respectively, and the 100% stress in the MD and CD directions of the first substrate 11 at 23°C is 3 MPa or more and 20 MPa or less, respectively. When the tensile modulus and 100% stress are within the above ranges, the first sheet 10 can be stretched significantly. The 100% stress of the first substrate 11 is a value obtained as follows. A test piece measuring 150 mm (length direction) x 15 mm (width direction) is cut out from the first substrate 11. Both ends of the cut out test piece in the length direction are gripped by grippers so that the length between the grippers is 100 mm. After gripping the test piece with the grippers, it is pulled in the length direction at a speed of 200 mm / min, and the measured value of the tensile force is read when the length between the grippers becomes 200 mm. The 100% stress of the first substrate 11 is a value obtained by dividing the measured value of the tensile force read by the cross-sectional area of ​​the substrate. The cross-sectional area of ​​the first substrate 11 is calculated by the width direction length of 15 mm x the thickness of the first substrate 11 (test piece). The cutting is performed so that the flow direction (MD direction) or the direction perpendicular to the MD direction (CD direction) during the manufacture of the substrate coincides with the length direction of the test piece. In this tensile test, the thickness of the test piece is not particularly limited, and may be the same as the thickness of the substrate to be tested.

[0075] At 23° C., it is preferable that the breaking elongation of the first base material 11 in both the MD and CD directions is 100% or more. When the breaking elongation of the first base material 11 in both the MD and CD directions is 100% or more, the first sheet 10 can be stretched significantly without breaking.

[0076] The tensile modulus (MPa) and the breaking elongation (%) of the substrate can be measured as follows. The substrate is cut to 15 mm x 140 mm to obtain a test piece. The breaking elongation and tensile modulus of the test piece are measured at 23°C in accordance with JIS K7161:2014 and JIS K7127:1999. Specifically, the test piece is subjected to a tensile test at a speed of 200 mm / min using a tensile tester (manufactured by Shimadzu Corporation, product name "Autograph AG-IS 500N") with the chuck distance set to 100 mm, and the breaking elongation (%) and tensile modulus (MPa) are measured. The measurements are performed in both the machine direction (MD) during the manufacture of the substrate and the direction perpendicular thereto (CD).

[0077] ·1st adhesive layer The constituent material of the first pressure-sensitive adhesive layer 12 is not particularly limited as long as it can function appropriately in a desired process such as an expanding process. Examples of the pressure-sensitive adhesive contained in the first pressure-sensitive adhesive layer 12 include a rubber-based pressure-sensitive adhesive, an acrylic-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, a polyester-based pressure-sensitive adhesive, and a urethane-based pressure-sensitive adhesive.

[0078] Energy ray curable resin (ax1) The first pressure-sensitive adhesive layer 12 preferably contains an energy ray-curable resin (ax1). The energy ray-curable resin (ax1) has an energy ray-curable double bond in the molecule. The pressure-sensitive adhesive layer containing the energy ray-curable resin is cured by irradiation with energy rays, and the adhesive strength is reduced. When it is desired to separate the adhesive sheet from the adherend, separation can be easily achieved by irradiating the pressure-sensitive adhesive layer with energy rays.

[0079] The energy ray curable resin (ax1) is preferably a (meth)acrylic resin.

[0080] The energy ray curable resin (ax1) is preferably an ultraviolet ray curable resin, and more preferably an ultraviolet ray curable (meth)acrylic resin.

[0081] The energy ray curable resin (ax1) is a resin that is polymerized and cured when irradiated with energy rays, such as ultraviolet rays and electron beams. Examples of the energy ray curable resin (ax1) include low molecular weight compounds having an energy ray polymerizable group (monofunctional monomers, polyfunctional monomers, monofunctional oligomers, and polyfunctional oligomers).Specific examples of the energy ray curable resin (ax1) include acrylates such as trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, pentaerythritol triacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, 1,4-butylene glycol diacrylate, and 1,6-hexanediol diacrylate, cyclic aliphatic skeleton-containing acrylates 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) may be used alone or in combination of two or more.

[0082] The molecular weight of the energy ray curable resin (ax1) is usually 100 or more and 30,000 or less, and preferably about 300 or more and 10,000 or less.

[0083] (Meth)acrylic copolymer (b1) The first pressure-sensitive adhesive layer 12 preferably further contains a (meth)acrylic copolymer (b1). The (meth)acrylic copolymer is different from the above-mentioned energy ray curable resin (ax1).

[0084] The (meth)acrylic copolymer (b1) preferably has an energy ray-curable carbon-carbon double bond. That is, in the present embodiment, the first pressure-sensitive adhesive layer 12 preferably contains an energy ray-curable resin (ax1) and an energy ray-curable (meth)acrylic copolymer (b1).

[0085] The first adhesive layer 12 preferably contains 10 parts by mass or more of the energy ray curable resin (ax1) per 100 parts by mass of the (meth)acrylic copolymer (b1), more preferably contains 20 parts by mass or more, and even more preferably contains 25 parts by mass or more. The first adhesive layer 12 preferably contains 80 parts by mass or less of the energy ray curable resin (ax1) per 100 parts by mass of the (meth)acrylic copolymer (b1), more preferably contains 70 parts by mass or less, and even more preferably contains 60 parts by mass or less.

[0086] 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. 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. In this specification, the weight average molecular weight (Mw) is a value measured by gel permeation chromatography (GPC) in terms of standard polystyrene.

[0087] The (meth)acrylic copolymer (b1) is preferably a (meth)acrylic acid ester polymer (b2) (hereinafter sometimes referred to as "energy ray-curable polymer (b2)") having a functional group having energy ray curability (energy ray-curable group) introduced into the side chain.

[0088] Energy beam curable polymer (b2) The energy ray curable polymer (b2) is preferably a copolymer obtained by reacting an acrylic copolymer (b21) having a functional group-containing monomer unit with an unsaturated group-containing compound (b22) having a functional group bonded to the functional group.

[0089] In this specification, (meth)acrylic acid ester means both acrylic acid ester and methacrylic acid ester, as well as other similar terms.

[0090] The acrylic copolymer (b21) preferably contains a structural unit derived from a functional group-containing monomer and a structural unit derived from a (meth)acrylic acid ester monomer or a derivative of a (meth)acrylic acid ester monomer.

[0091] The functional group-containing monomer as a structural 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 selected from the group consisting of a hydroxy group, a carboxy group, an amino group, a substituted amino group, an epoxy group, and the like.

[0092] Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. The hydroxyl group-containing monomer may be used alone or in combination of two or more.

[0093] Examples of the carboxyl group-containing monomer include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, citraconic acid, etc. The carboxyl group-containing monomer may be used alone or in combination of two or more.

[0094] Examples of the amino group-containing monomer or substituted amino group-containing monomer include aminoethyl (meth)acrylate and n-butylaminoethyl (meth)acrylate. The amino group-containing monomer or substituted amino group-containing monomer may be used alone or in combination of two or more.

[0095] As the (meth)acrylic acid ester monomer constituting the acrylic copolymer (b21), in addition to alkyl (meth)acrylates in which the alkyl group has 1 to 20 carbon atoms, for example, monomers having an alicyclic structure in the molecule (alicyclic structure-containing monomers) are preferably used.

[0096] The alkyl (meth)acrylate is preferably an alkyl (meth)acrylate having an alkyl group with a carbon number of 1 to 18. More preferred examples of the alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. The alkyl (meth)acrylate may be used alone or in combination of two or more.

[0097] As the alicyclic structure-containing monomer, for example, cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, adamantyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, etc. are preferably used. The alicyclic structure-containing monomer is used alone or in combination of two or more.

[0098] The acrylic copolymer (b21) preferably contains the structural units derived from the functional group-containing monomer in a proportion of 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more. In addition, the acrylic copolymer (b21) preferably contains the structural units derived from the functional group-containing monomer in a proportion of 35% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less.

[0099] Furthermore, the acrylic copolymer (b21) preferably contains structural units derived from a (meth)acrylic acid ester monomer or a derivative thereof in a proportion of 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more. Furthermore, the acrylic copolymer (b21) preferably contains structural units derived from a (meth)acrylic acid ester monomer or a derivative thereof in a proportion of 99% by mass or less, more preferably 95% by mass or less, and even more preferably 90% by mass or less.

[0100] The acrylic copolymer (b21) can be obtained by copolymerizing the above-mentioned functional group-containing monomer with a (meth)acrylic acid ester monomer or a derivative thereof in a conventional manner. The acrylic copolymer (b21) may contain at least one structural unit selected from the group consisting of dimethylacrylamide, vinyl formate, vinyl acetate, styrene, and the like, in addition to the above-mentioned monomers.

[0101] The acrylic copolymer (b21) having the 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).

[0102] The functional group of the unsaturated group-containing compound (b22) can be appropriately selected depending on 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, and 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 carboxy group, or an aziridinyl group.

[0103] The unsaturated group-containing compound (b22) contains at least one energy ray-polymerizable carbon-carbon double bond in one molecule, preferably 1 to 6, and more preferably 1 to 4.

[0104] Examples of the unsaturated group-containing compound (b22) include 2-methacryloyloxyethyl isocyanate (2-isocyanatoethyl methacrylate), meta-isopropenyl-α,α-dimethylbenzyl isocyanate, methacryloyl isocyanate, allyl isocyanate, 1,1-(bisacryloyloxymethyl)ethyl isocyanate; an acryloyl monoisocyanate compound obtained by reacting a diisocyanate compound or a polyisocyanate compound with hydroxyethyl (meth)acrylate; an acryloyl monoisocyanate compound obtained by reacting a diisocyanate compound or a polyisocyanate compound with a polyol compound and hydroxyethyl (meth)acrylate; glycidyl (meth)acrylate; (meth)acrylic acid, 2-(1-aziridinyl)ethyl (meth)acrylate, 2-vinyl-2-oxazoline, 2-isopropenyl-2-oxazoline, and the like.

[0105] The unsaturated group-containing compound (b22) is preferably used in a proportion (addition rate) of 50 mol % or more, more preferably 60 mol % or more, and even more preferably 70 mol % or more, based on the number of moles of the functional group-containing monomer in the acrylic copolymer (b21). In addition, the unsaturated group-containing compound (b22) is preferably used in a proportion of 95 mol % or less, more preferably 93 mol % or less, and even more preferably 90 mol % or less, based on the number of moles of the functional group-containing monomer in the acrylic copolymer (b21).

[0106] 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 type of catalyst can be appropriately selected according to the combination of the functional group of the acrylic copolymer (b21) and the functional group of the unsaturated group-containing compound (b22). As a result, the functional group of the acrylic copolymer (b21) reacts with the functional group of the unsaturated group-containing compound (b22), and the unsaturated group is introduced into the side chain of the acrylic copolymer (b21), thereby obtaining the energy radiation curable polymer (b2).

[0107] 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. 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.

[0108] Photopolymerization initiator (C) When the first pressure-sensitive adhesive layer 12 contains an ultraviolet-curable compound (for example, an ultraviolet-curable resin), the first pressure-sensitive adhesive layer 12 preferably contains a photopolymerization initiator (C). By including the photopolymerization initiator (C) in the first pressure-sensitive adhesive layer 12, the polymerization curing time and the light irradiation dose can be reduced.

[0109] Specific examples of the photopolymerization initiator (C) include benzoin compounds, acetophenone compounds, acylphosphinoxide compounds, titanocene compounds, thioxanthone compounds, and peroxide compounds.Further, examples of the photopolymerization initiator (C) include photosensitizers such as amines and quinones. More specific examples of the photopolymerization initiator (C) include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl phenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyrolnitrile, dibenzyl, diacetyl, 8-chloroanthraquinone, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide. The photopolymerization initiator (C) may be used alone or in combination of two or more.

[0110] The amount of the photopolymerization initiator (C) is preferably 0.01 parts by mass or more and 10 parts by mass or less, more preferably 0.03 parts by mass or more and 5 parts by mass or less, and even more preferably 0.05 parts by mass or more and 5 parts by mass or less, relative to 100 parts by mass of the adhesive resin.

[0111] When the pressure-sensitive adhesive layer contains an energy ray curable resin (ax1) and a (meth)acrylic copolymer (b1), the photopolymerization initiator (C) is preferably used in an amount of 0.1 parts by mass or more, and more preferably 0.5 parts by mass or more, per 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 blended in the pressure-sensitive adhesive layer, the photopolymerization initiator (C) is preferably used in an amount of 10 parts by mass or less, and more preferably 6 parts by mass or less, per 100 parts by mass of the total amount of the energy ray curable resin (ax1) and the (meth)acrylic copolymer (b1).

[0112] In addition to the above components, other components may be appropriately blended into the first pressure-sensitive adhesive layer 12. Examples of other components include a crosslinking agent (E).

[0113] Crosslinking agent (E) As the crosslinking agent (E), a polyfunctional compound having reactivity with the functional groups of the (meth)acrylic copolymer (b1) etc. can be used. Examples of the polyfunctional compound in the first sheet 10 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 phenol resins.

[0114] The amount of the crosslinking agent (E) is preferably 0.01 part by mass or more, more preferably 0.03 part by mass or more, and even more preferably 0.04 part by mass or more, based on 100 parts by mass of the (meth)acrylic copolymer (b1). The amount of the crosslinking agent (E) 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, per 100 parts by mass of the (meth)acrylic copolymer (b1).

[0115] The thickness of the first pressure-sensitive adhesive layer 12 is not particularly limited. For example, the thickness of the first pressure-sensitive adhesive layer 12 is preferably 10 μm or more, and more preferably 20 μm or more. Moreover, the thickness of the first pressure-sensitive adhesive layer 12 is preferably 150 μm or less, and more preferably 100 μm or less.

[0116] The recovery rate of the first sheet 10 is preferably 70% or more, more preferably 80% or more, and even more preferably 85% or more. The recovery rate of the first sheet 10 is preferably 100% or less. When the recovery rate is within the above range, the pressure-sensitive adhesive sheet can be greatly stretched. The recovery rate was measured by cutting a test piece of 150 mm (lengthwise) x 15 mm (widthwise) from an adhesive sheet, gripping both ends in the lengthwise direction with grippers so that the length between the grippers was 100 mm, pulling at a speed of 200 mm / min until the length between the grippers was 200 mm, holding the expanded length at 200 mm for 1 minute, and then returning the test piece to the lengthwise direction at a speed of 200 mm / min until the length between the grippers was 100 mm, and then pulling at a speed of 200 mm / min until the length between the grippers was 100 mm. The length between the grippers is returned to 100 mm and held in that state for 1 minute, and then pulled in the longitudinal direction at a speed of 60 mm / min. The length between the grippers is measured when the measured tensile force is 0.1 N / 15 mm. L2 (mm) is the length obtained by subtracting the initial length between the grippers of 100 mm from this length, and L1 (mm) is the length between the grippers in the expanded state of 200 mm minus the initial length between the grippers of 100 mm. L2 can be calculated using the following formula (Equation 2). Recovery rate (%) = {1-(L2÷L1)} × 100 (Equation 2)

[0117] When the recovery rate is within the above range, it means that the adhesive sheet is easy to restore even after being greatly stretched. In general, when a sheet having a yield point is stretched beyond the yield point, the sheet undergoes plastic deformation, and the plastically deformed portion, i.e., the extremely stretched portion, becomes unevenly distributed. When the sheet in such a state is further stretched, the extremely stretched portion breaks, or even if no break occurs, the expansion becomes uneven. In addition, even if the sheet does not have a clear yield point and does not take a stress value where the slope dx / dy changes from a positive value to 0 or a negative value in a stress-strain diagram in which the strain is plotted on the x-axis and the elongation is plotted on the y-axis, the sheet undergoes plastic deformation as the pulling amount increases, and similarly breaks or becomes unevenly expanded. On the other hand, when elastic deformation occurs instead of plastic deformation, the sheet is easy to restore to its original shape by removing the stress. Therefore, by having the recovery rate, which is an index showing the degree of recovery after 100% elongation, which is a sufficiently large tensile amount, within the above range, plastic deformation of the film is minimized when the adhesive sheet is significantly stretched, making it less likely to break and enabling uniform expansion.

[0118] (Release sheet) A release sheet may be attached to the surface of the first sheet 10. Specifically, the release sheet is attached to the surface of the first adhesive layer 12 of the first sheet 10. The release sheet protects the first adhesive layer 12 during transportation and storage by being attached to the surface of the first adhesive layer 12. The release sheet is releasably attached to the first sheet 10, and is peeled off and removed from the first sheet 10 before the first sheet 10 is used.

[0119] The release sheet used is a release sheet having at least one surface subjected to a release treatment. Specifically, for example, the release sheet includes a release sheet substrate and a release agent layer formed by applying a release agent onto the surface of the substrate.

[0120] The release sheet substrate is preferably a resin film. Examples of the resin constituting the resin film as the release 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 release agent include rubber-based elastomers such as silicone-based resins, olefin-based resins, isoprene-based resins, and butadiene-based resins, long-chain alkyl-based resins, alkyd-based resins, and fluorine-based resins.

[0121] The thickness of the release sheet is not particularly limited, but is preferably 10 μm or more and 200 μm or less, and more preferably 20 μm or more and 150 μm or less.

[0122] (Method of manufacturing pressure-sensitive adhesive sheet) There are no particular limitations on the method for producing the first sheet 10 and other pressure-sensitive adhesive sheets described herein, and they can be produced by known methods.

[0123] For example, the adhesive layer provided on the release sheet can be laminated to one side of the substrate to produce an adhesive sheet with the release sheet attached to the surface of the adhesive layer. Also, the buffer layer provided on the release sheet can be laminated to the substrate and the release sheet can be removed to produce a laminate of the buffer layer and the substrate. Then, the adhesive layer provided on the release sheet can be laminated to the substrate side of the laminate to produce an adhesive sheet with the release sheet attached to the surface of the adhesive layer. When the buffer layer is provided on both sides of the substrate, the adhesive layer is formed on the buffer layer. The release sheet attached to the surface of the adhesive layer can be appropriately peeled off and removed before using the adhesive sheet.

[0124] A more specific example of the method for producing a pressure-sensitive adhesive sheet includes the following method. First, a coating liquid containing a pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer and, if desired, a solvent or a dispersion medium is prepared. Next, the coating liquid is applied to one surface of the substrate by a coating means to form a coating film. Examples of the coating means include a die coater, a curtain coater, a spray coater, a slit coater, and a knife coater. Next, the coating film is dried to form a pressure-sensitive adhesive layer. The properties of the coating liquid are not particularly limited as long as it can be applied. The coating liquid may contain a component for forming the pressure-sensitive adhesive layer as a solute, or may contain a component for forming the pressure-sensitive adhesive layer as a dispersoid. Similarly, the pressure-sensitive adhesive layer may be formed by directly applying the pressure-sensitive adhesive composition to one surface of the substrate or onto the buffer layer.

[0125] Another specific example of the method for producing a pressure-sensitive adhesive sheet is as follows. First, a coating liquid is applied onto the release surface of the release sheet to form a coating film. Next, the coating film is dried to form a laminate consisting of a pressure-sensitive adhesive layer and a release sheet. Next, a substrate may be attached to the surface of the pressure-sensitive adhesive layer of this laminate opposite to the release sheet side to obtain a laminate of a pressure-sensitive adhesive sheet and a release sheet. The release sheet in this laminate may be peeled off as a processing material, or may protect the pressure-sensitive adhesive layer until an adherend (e.g., a semiconductor chip, a semiconductor wafer, etc.) is attached to the pressure-sensitive adhesive layer.

[0126] When the coating liquid contains a crosslinking agent, the crosslinking reaction between the (meth)acrylic copolymer in the coating film and the crosslinking agent may be advanced by changing the drying conditions (e.g., temperature, time, etc.) of the coating film or by separately carrying out a heat treatment, and a crosslinked structure may be formed at a desired density in the adhesive layer. In order to advance this crosslinking reaction sufficiently, after laminating the adhesive layer on the substrate by the above-mentioned method, the obtained adhesive sheet may be cured by, for example, leaving it in an environment of 23°C and a relative humidity of 50% for several days.

[0127] The thickness of the first sheet 10 is preferably 30 μm or more, and more preferably 50 μm or more. The thickness of the first sheet 10 is preferably 400 μm or less, and more preferably 300 μm or less.

[0128] (Second adhesive sheet) The second adhesive sheet 20 according to this embodiment has a second substrate 21 and a second adhesive layer 22. The second adhesive layer 22 is laminated on the second substrate 21.

[0129] ·Second base material The material of the second base material 21 according to this embodiment is not particularly limited as long as it can function appropriately in a desired process such as a dicing process. The second base material 21 is preferably made of a film mainly made of a resin-based material. Examples of films mainly made of a resin-based material include ethylene copolymer films, polyolefin films, polyvinyl chloride films, polyester films, polyurethane films, polyimide films, polystyrene films, polycarbonate films, and fluororesin films.

[0130] ·Second adhesive layer There are no particular limitations on the material constituting second adhesive layer 22, so long as it can function appropriately in the desired process, such as a dicing process.

[0131] The second adhesive layer 22 is preferably composed of at least one adhesive selected from the group consisting of, for example, an acrylic adhesive, a urethane adhesive, a polyester adhesive, a rubber adhesive, and a silicone adhesive, and is more preferably composed of an acrylic adhesive.

[0132] The second adhesive layer 22 may be made of a non-energy ray curable adhesive, or may be made of an energy ray curable adhesive.

[0133] [Effects of this embodiment] According to the expanding method of this embodiment, when the first sheet 10 is expanded, the circuit surface W1 of the semiconductor chip CP is not in contact with the first adhesive layer 12 of the first sheet 10. In each of the semiconductor chips CP, the protective layer 100, which has been singulated in the dicing process, is interposed between the circuit surface W1 and the first adhesive layer 12, so that the protective layer 100 in contact with the circuit surface W1 is not stretched even when the first sheet 10 is expanded. As a result, according to the expanding method of this embodiment, adhesive residue can be suppressed. In addition, the adhesive sheets used in the expanding method according to the present embodiment are all simply configured to consist of a substrate and an adhesive layer. In addition, since the adhesive sheet used in the dicing step is replaced with an adhesive sheet for the expanding step before the expanding step, there is no need to carefully control the cutting depth so that the dicing blade does not reach the substrate of the dicing sheet in the dicing step. Therefore, according to the expanding method of this embodiment, the pressure-sensitive adhesive sheet configuration and process can be simplified compared to conventional methods, and adhesive residue can be suppressed. Furthermore, it is possible to provide a method for manufacturing a semiconductor device including the expanding method according to this embodiment.

[0134] Second Embodiment Next, a second embodiment of the present invention will be described. The first and second embodiments differ mainly in the following respects: In the first embodiment, a protective layer is provided on a first surface (circuit surface W1) of the object to be processed (semiconductor wafer W), whereas in the second embodiment, a protective layer is provided on the object to be processed by attaching a second surface (rear surface W3) of the object to be processed (semiconductor wafer W) to a protective layer of a composite sheet having a protective layer and a third sheet. In the following description, differences from the first embodiment will be mainly described, and overlapping descriptions will be omitted or simplified. The same components as those in the first embodiment will be denoted by the same reference numerals, and descriptions thereof will be omitted or simplified.

[0135] 6 (FIGS. 6A, 6B, and 6C) and 7 (FIGS. 7A, 7B, and 7C) are schematic cross-sectional views illustrating a method for manufacturing a semiconductor device including an expanding method according to this embodiment.

[0136] The expanding method according to this embodiment includes the following steps (PX1) to (PX5). (PX1) A process of attaching an object to be processed to a protective layer of a composite sheet having a protective layer and a third sheet. (PX2) A process of cutting the wafer by making an incision from the first workpiece surface side of the workpiece, and further cutting at least the protective layer to separate into a plurality of semiconductor devices. The first workpiece surface becomes the circuit surface of the semiconductor device, and the second workpiece surface becomes the back surface of the semiconductor device. (PX3) A process of peeling off the third sheet while leaving the protective layer on the back surface of the semiconductor device. (PX4) A process of attaching a first sheet to the protective layer on the back surface side of the semiconductor device. (PX5) A process of expanding the first sheet to increase the spacing between the multiple semiconductor devices.

[0137] (Composite sheet) FIG. 6A shows a schematic cross-sectional view of a composite sheet 130 used in this embodiment. The composite sheet 130 has a protective layer 100A and a third sheet 30. The composite sheet 130 holds the semiconductor wafer W when the semiconductor wafer W is diced. The semiconductor wafer W is attached to the composite sheet 130 with the back surface W3 facing the protective layer 100A.

[0138] (protective layer) The protective layer 100A in the composite sheet 130 is laminated on the third sheet 30. The protective layer 100A is not particularly limited as long as it can be attached to the back surface W3 (back surface of the semiconductor device) of the semiconductor wafer W as the processing object and the semiconductor chip CP as the semiconductor device to protect the back surface W3. Examples of the protective layer 100A include a protective film and a protective sheet. The thickness of the protective layer 100A is preferably 1 μm or more, and more preferably 5 μm or more. The thickness of the protective layer 100A is preferably 500 μm or less, and more preferably 300 μm or less. The protective layer 100A may be, for example, a protective layer similar to the protective layer 100 described in the first embodiment.

[0139] (3rd sheet) The third sheet 30 in the composite sheet 130 is a member that supports the protective layer 100A. The material of the third sheet 30 is not particularly limited as long as it can support the protective layer 100A. In the step (PX3) of the present embodiment, since the third sheet 30 is peeled off while leaving the protective layer 100A on the rear surface W3 of the semiconductor chip CP, it is preferable that the third sheet 30 is composed of a material that can be peeled off from the protective layer 100A.

[0140] A more detailed example of the composite sheet 130 will be described later.

[0141] [Composite sheet attachment process] Fig. 6B is a diagram for explaining step (PX1). Fig. 6B shows a semiconductor wafer W to which a composite sheet 130 is attached. The semiconductor wafer W in this embodiment is also preferably a wafer obtained by going through a back grinding process. This step (PX1) may be referred to as a composite sheet attachment step. As described later, in step (PX2), the semiconductor wafer W is diced into a plurality of semiconductor chips CP. In this embodiment, when the semiconductor wafer W is diced, a composite sheet 130 is attached to the back surface W3 in order to hold the semiconductor wafer W. The semiconductor wafer W is attached with the back surface W3 facing the protective layer 100 of the composite sheet 130.

[0142] In this embodiment, an example is described in which the process is carried out with the circuit surface W1 exposed. Other examples include, for example, a process in which a protective member such as a protective sheet or protective film separate from the protective layer 100A is attached to the circuit surface W1.

[0143] [Dicing process] 6C is a diagram for explaining the step (PX2). The step (PX2) may be referred to as a dicing step. In FIG. 6C, a plurality of semiconductor chips CP held on a composite sheet 130 are shown. The semiconductor wafer W with the composite sheet 130 attached to the back surface W3 is diced into individual pieces to form a plurality of semiconductor chips CP. The circuit surface W1 as the first semiconductor device surface corresponds to the circuit surface of the chip. The back surface W3 as the second semiconductor device surface corresponds to the chip back surface. In this embodiment, the semiconductor wafer W is cut by making cuts from the circuit surface W1 side, and further at least the protective layer 100A of the composite sheet 130 is cut. The cutting depth during dicing is not particularly limited as long as the semiconductor wafer W and the protective layer 100A can be individually divided. In this embodiment, an example in which the cut is not made to the third sheet 30 is described, but the present invention is not limited to such an example. For example, in another embodiment, from the viewpoint of reliably cutting the semiconductor wafer W and the protective layer 100A, the cut may be made by dicing to a depth reaching the third sheet 30.

[0144] [Third sheet peeling process] Fig. 7A is a diagram for explaining step (PX3). Step (PX3) may be referred to as a third sheet peeling step. Fig. 7A shows a step of peeling off the third sheet 30 while leaving the protective layer 100A on the back surface W3 of the semiconductor chip CP that has been singulated after the dicing step. In one embodiment of the composite sheet 130, when the protective layer 100A is laminated directly on the third sheet 30, in the peeling step of the third sheet, it is preferable to peel the third sheet at the interface between the protective layer 100A and the third sheet 30. When the third sheet 30 is peeled off, a plurality of semiconductor chips CP having the protective layer 100A attached to the back surface W3 are obtained.

[0145] The peeling force when peeling the third sheet 30 from the protective layer 100A is preferably 10 mN / 25 mm or more and 2000 mN / 25 mm or less. When the peeling force when peeling the third sheet 30 from the protective layer 100A is 10 mN / 25 mm or more, the effect of excellent semiconductor chip retention during dicing is obtained. When the peeling force when peeling the third sheet 30 from the protective layer 100A is 2000 mN / 25 mm or less, the effect of excellent semiconductor chip pickup after dicing is obtained. When peeling the third sheet 30 from the protective layer 100A, the peeling force 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.

[0146] [First sheet attachment process] Fig. 7B is a diagram for explaining step (PX4). Step (PX4) may be referred to as a first sheet attachment step. Fig. 7B shows a state in which the first sheet 10 is attached to a plurality of semiconductor chips CP obtained by the dicing step. The first sheet 10 according to this embodiment is similar to the first sheet 10 used in the first embodiment. In this embodiment, when the first sheet 10 is attached to the back surface W3 side of multiple semiconductor chips CP, a laminated structure is obtained in which individualized protective layers 100A are interposed between the multiple semiconductor chips CP and the first adhesive layer 12 of the first sheet 10.

[0147] [Expanding process] Fig. 7C is a diagram for explaining step (PX5). Step (PX5) may be referred to as an expanding step. Fig. 7C shows a state in which the first sheet 10 is expanded after the first sheet 10 is attached to expand the intervals between the multiple semiconductor chips CP. In the expanding step in this embodiment, the method of stretching the first sheet 10 is the same as in the first embodiment. In this embodiment, the spacing D1 between the multiple semiconductor chips CP is not particularly limited because it depends on the size of the semiconductor chips CP. The spacing D1 between adjacent semiconductor chips CP is preferably 200 μm or more. The upper limit of the spacing between the semiconductor chips CP is not particularly limited. The upper limit of the spacing between the semiconductor chips CP may be, for example, 6000 μm.

[0148] [First transfer process] In this embodiment, after the expanding process, a process may be carried out in which the multiple semiconductor chips CP attached to the first sheet 10 are transferred to a sixth adhesive sheet 60 (hereinafter sometimes referred to as the "first transfer process") in the same manner as in the first embodiment.

[0149] When the transfer step is performed in this embodiment, for example, after the expanding step, it is preferable to attach the sixth adhesive sheet 60 to the circuit surface W1 of the semiconductor chips CP, and then peel the first sheet 10 and the protective layer 100A from the back surface W3. The first sheet 10 and the protective layer 100A may be peeled off from the back surface W3 together, or the first sheet 10 may be peeled off first and then the protective layer 100A may be peeled off from the back surface W3. The step of peeling the protective layer 100A from the back surface W3 may be referred to as a protective layer peeling step. It is preferable that the distances D1 between the multiple semiconductor chips CP expanded in the expanding step be maintained even after the peeling step of the protective layer 100A.

[0150] From the viewpoint of suppressing adhesive residue on the back surface W3 when peeling the protective layer 100A from the back surface W3, the protective layer 100A preferably contains a first energy ray curable resin. When the protective layer 100A contains the first energy ray curable resin, the protective layer 100A 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 protective layer 100A is increased, and the adhesive force between the protective layer 100A and the back surface W3 of the semiconductor chip CP can be reduced or eliminated. Examples of the energy ray 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.

[0151] From the viewpoint of peeling off the first sheet 10 together with the protective layer 100A from the back surface W3, when the first sheet 10 includes the first adhesive layer 12, the first adhesive layer 12 preferably contains a second energy ray curable resin. When the protective layer 100A contains the first energy ray curable resin and the first adhesive layer 12 contains the second energy ray curable resin, the first adhesive layer 12 and the protective layer 100A are irradiated with energy rays from the first base material 11 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 ray curable resin include ultraviolet rays (UV) and electron beams (EB), and ultraviolet rays are preferred. Therefore, the second energy ray curable resin is preferably an ultraviolet ray curable resin. The first base material 11 preferably has transparency to energy rays.

[0152] In addition, as an aspect different from the present embodiment, the protective layer 100A may be used as a protective film for protecting the rear surface W3 of the semiconductor chip CP without peeling it off from the rear surface W3 of the semiconductor chip CP. When the protective layer 100A is used as a protective film for the rear surface W3, it is preferable that the protective layer 100A contains a curable adhesive composition.

[0153] [Sealing process and other processes] In this embodiment, similarly to the first embodiment, a sealing step and other steps (a rewiring layer forming step and a connection step with external terminal electrodes) may be performed.

[0154] (Composite sheet) In one aspect of the present embodiment, it is also preferred that protective layer 100A of composite sheet 130 is a third pressure-sensitive adhesive layer, and third sheet 30 is a third substrate. That is, it is preferred that composite sheet 130 is a pressure-sensitive adhesive sheet having a third substrate and a third pressure-sensitive adhesive layer, and that the third substrate and the third pressure-sensitive adhesive layer are peelable from each other.

[0155] ·Third base material The third substrate according to the present embodiment is not particularly limited in terms of its constituent material, so long as it can function appropriately in a desired process. The third substrate is a member that supports the third pressure-sensitive adhesive layer. The third substrate is, for example, a resin film. Examples of the resin film include at least one film selected from the group consisting of a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, a vinyl chloride copolymer film, a polyethylene terephthalate film, a polyethylene naphthalate film, a polybutylene terephthalate film, a polyurethane film, an ethylene-vinyl acetate copolymer film, an ionomer resin film, an ethylene-(meth)acrylic acid copolymer film, an ethylene-(meth)acrylic acid ester copolymer film, a polystyrene film, a polycarbonate film, a polyimide film, and a fluororesin film. In addition, crosslinked films of these are also used as the third substrate. Furthermore, the third substrate may be a laminated film of these.

[0156] The third substrate may be, for example, a hard support. The material of the hard support may be appropriately determined in consideration of mechanical strength, heat resistance, and the like. Examples of the material of the hard support include metal materials such as SUS; non-metallic inorganic materials such as glass and silicon wafer; resin materials such as epoxy, ABS, acrylic, engineering plastics, super engineering plastics, polyimide, and polyamideimide; and composite materials such as glass epoxy resin. Among these, SUS, glass, and silicon wafer are preferable. Examples of engineering plastics include nylon, polycarbonate (PC), and polyethylene terephthalate (PET). Examples of super engineering plastics include polyphenylene sulfide (PPS), polyethersulfone (PES), and polyetheretherketone (PEEK).

[0157] The thickness of the third substrate is not particularly limited. The thickness of the third substrate is preferably 20 μm or more and 50 mm or less, more preferably 60 μm or more and 20 mm or less. By setting the thickness of the third substrate within the above range, when the third substrate is a resin film, the third sheet 30 has sufficient flexibility and therefore exhibits good attachment to the workpiece (work). The workpiece is, for example, a wafer or a semiconductor element, and more specifically, a semiconductor wafer or a semiconductor chip. When the third substrate is a hard substrate, the thickness of the hard substrate may be appropriately determined in consideration of mechanical strength, handling, and the like. The thickness of the hard substrate is, for example, 100 μm or more and 50 mm or less.

[0158] ·Third adhesive layer The material constituting the third pressure-sensitive adhesive layer is not particularly limited, so long as it can function appropriately in the desired process. In one embodiment of the third adhesive layer, it is preferably composed of at least one adhesive selected from the group consisting of an acrylic adhesive, a urethane adhesive, a polyester adhesive, a rubber adhesive, and a silicone adhesive, and it is more preferably composed of an acrylic adhesive.

[0159] In one embodiment of the third adhesive layer, it is preferable that the third adhesive layer contains a curable adhesive composition that cures when it receives energy from the outside. Examples of energy supplied from the outside include ultraviolet light, electron beams, and heat. It is preferable that the third adhesive layer contains at least one of an ultraviolet-curable adhesive and a heat-curable adhesive. When the third base material has heat resistance, the adhesive layer is preferably a heat-curable adhesive layer containing a heat-curable adhesive, since the generation of residual stress during heat curing can be suppressed.

[0160] The third pressure-sensitive adhesive layer contains, for example, a first adhesive composition. The first adhesive composition contains a binder polymer component (A) and a curable component (B).

[0161] (A) Binder polymer component The binder polymer component (A) is used to impart sufficient adhesion and film-forming properties (sheet-forming properties) to the third pressure-sensitive adhesive layer. As the binder polymer component (A), a conventionally known acrylic polymer, polyester resin, urethane resin, acrylic urethane resin, silicone resin, rubber-based polymer, etc. can be used.

[0162] The weight average molecular weight (Mw) of the binder polymer component (A) is preferably 10,000 or more and 2,000,000 or less, and more preferably 100,000 or more and 1,200,000 or less. In this specification, the weight average molecular weight (Mw) is a standard polystyrene equivalent value measured by gel permeation chromatography (GPC).

[0163] As the binder polymer component (A), an acrylic polymer is preferably used. The glass transition temperature (Tg) of the acrylic polymer is preferably in the range of -60°C or more and 50°C or less, more preferably -50°C or more and 40°C or less, and even more preferably -40°C or more and 30°C or less.

[0164] Examples of monomers constituting the acrylic polymer include (meth)acrylic acid ester monomers or derivatives thereof. For example, alkyl (meth)acrylates 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., can be mentioned. In addition, (meth)acrylates having a cyclic skeleton, specifically cyclohexyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, imide (meth)acrylate, etc. can be mentioned. Furthermore, examples of monomers having a functional group include hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, etc. having a hydroxyl group; and other examples include glycidyl (meth)acrylate having an epoxy group. The acrylic polymer is preferably an acrylic polymer containing a monomer having a hydroxyl group, since it has good compatibility with the curable component (B) described later. The acrylic polymer may be copolymerized with at least one selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, vinyl acetate, acrylonitrile, and styrene.

[0165] Furthermore, a thermoplastic resin may be blended as the binder polymer component (A) to maintain the flexibility of the film of the third pressure-sensitive adhesive layer after curing. Such a thermoplastic resin is preferably a resin having a weight average molecular weight of 1000 or more and 100,000 or less, more preferably a resin having a weight average molecular weight of 3000 or more and 80,000 or less. The glass transition temperature of the thermoplastic resin is preferably -30°C or more and 120°C or less, more preferably -20°C or more and 120°C or less. Examples of the thermoplastic resin include polyester resin, urethane resin, phenoxy resin, polybutene, polybutadiene, and polystyrene. These thermoplastic resins can be used alone or in combination of two or more.

[0166] (B) Curable component At least one of a thermosetting component and an energy ray curable component is used as the curable component (B). A thermosetting component and an energy ray curable component may be used as the curable component (B).

[0167] The thermosetting component includes a thermosetting resin and a thermosetting agent. The thermosetting resin is preferably, for example, an epoxy resin.

[0168] As the epoxy resin, a conventionally known epoxy resin can be used. Specific examples of the epoxy resin include polyfunctional epoxy resins, bisphenol A diglycidyl ether and its hydrogenated products, orthocresol novolac epoxy resins, dicyclopentadiene type epoxy resins, biphenyl type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, and phenylene skeleton type epoxy resins, and other epoxy compounds having two or more functional groups in the molecule. These can be used alone or in combination of two or more.

[0169] The third adhesive layer contains, per 100 parts by mass of the binder polymer component (A), preferably 1 part by mass or more and 1000 parts by mass or less of the thermosetting resin, more preferably 10 parts by mass or more and 500 parts by mass or less, and even more preferably 20 parts by mass or more and 200 parts by mass or less. If the content of the thermosetting resin is 1 part by mass or more, the problem of insufficient adhesiveness being not obtained can be suppressed. If the content of the thermosetting resin is 1000 parts by mass or less, the peel force between the third adhesive layer and the third base material can be prevented from becoming too high. Preventing the peel force from becoming too high can prevent transfer failure of the third adhesive layer to the back surface W3 of the semiconductor chip CP.

[0170] The heat curing agent functions as a curing agent for thermosetting resins, particularly epoxy resins. A preferred heat curing agent is a compound having two or more functional groups in one molecule that can react with an epoxy group. Examples of functional groups that can react with an epoxy group include a phenolic hydroxyl group, an alcoholic hydroxyl group, an amino group, a carboxyl group, and an acid anhydride group. Of these, preferred are a phenolic hydroxyl group, an amino group, and an acid anhydride group, and more preferred are a phenolic hydroxyl group and an amino group.

[0171] Specific examples of phenol-based hardeners include polyfunctional phenol resins, biphenols, novolac-type phenol resins, dicyclopentadiene-based phenol resins, xylok-type phenol resins, and aralkyl phenol resins.Specific examples of amine-based hardeners include DICY (dicyandiamide).These heat hardeners can be used alone or in combination of two or more.

[0172] The content of the thermosetting agent is preferably 0.1 parts by mass or more and 500 parts by mass or less, and more preferably 1 part by mass or more and 200 parts by mass or less, relative to 100 parts by mass of the thermosetting resin.

[0173] When the third pressure-sensitive adhesive layer contains a thermosetting component as the curable component (B), the third pressure-sensitive adhesive layer has thermosetting properties. In this case, the third pressure-sensitive adhesive layer can be cured by heating. In the first sheet 10 of the present embodiment, when the third base material has heat resistance, residual stress is unlikely to occur in the base material during thermal curing of the third pressure-sensitive adhesive layer, which would cause problems.

[0174] As the energy ray curable component, a low molecular weight compound (energy ray polymerizable compound) that contains an energy ray polymerizable group and is polymerized and cured when irradiated with energy rays such as ultraviolet rays and electron beams can be used. Specific examples of such energy ray curable components include trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, or acrylate-based compounds such as 1,4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, oligoester acrylate, urethane acrylate-based oligomer, epoxy modified acrylate, polyether acrylate, and itaconic acid oligomer. Such compounds have at least one polymerizable double bond in the molecule, and usually have a weight average molecular weight of 100 or more and 30,000 or less, preferably 300 or more and 10,000 or less. The amount of the energy ray-polymerizable compound is preferably 1 part by mass or more and 1,500 parts by mass or less, more preferably 10 parts by mass or more and 500 parts by mass or less, and even more preferably 20 parts by mass or more and 200 parts by mass or less, relative to 100 parts by mass of the binder polymer component (A).

[0175] In addition, as the energy ray curable component, an energy ray curable polymer having an energy ray polymerizable group bonded to the main chain or side chain of the binder polymer component (A) may be used. Such an energy ray curable polymer has both the function as the binder polymer component (A) and the function as the curable component (B).

[0176] The main skeleton of the energy ray curable polymer is not particularly limited, and may be an acrylic polymer that is widely used as the binder polymer component (A), or may be polyester, polyether, or the like. However, it is preferable to use an acrylic polymer as the main skeleton because it is easy to synthesize and control the physical properties.

[0177] The energy ray-polymerizable group bonded to the main chain or side chain of the energy ray-curable polymer is, for example, a group containing an energy ray-polymerizable carbon-carbon double bond, and specific examples thereof include a (meth)acryloyl group, etc. The energy ray-polymerizable group may be bonded to the energy ray-curable polymer via an alkylene group, an alkyleneoxy group, or a polyalkyleneoxy group.

[0178] The weight average molecular weight (Mw) of the energy ray curable polymer having the energy ray polymerizable group bonded thereto is preferably 10,000 to 2,000,000, and more preferably 100,000 to 1,500,000. The glass transition temperature (Tg) of the energy ray curable polymer is preferably -60°C to 50°C, more preferably -50°C to 40°C, and even more preferably -40°C to 30°C.

[0179] The energy beam curable polymer is obtained, for example, by reacting an acrylic polymer containing a functional group with a polymerizable group-containing compound. Examples of the functional group of the acrylic polymer containing a functional group include a hydroxyl group, a carboxyl group, an amino group, a substituted amino group, and an epoxy group. The polymerizable group-containing compound is a polymerizable group-containing compound having a substituent that reacts with the substituent of the acrylic polymer and 1 to 5 energy beam polymerizable carbon-carbon double bonds per molecule. Examples of the substituent that reacts with the functional group include an isocyanate group, a glycidyl group, and a carboxyl group.

[0180] Examples of the polymerizable group-containing compound include (meth)acryloyloxyethyl isocyanate, meta-isopropenyl-α,α-dimethylbenzyl isocyanate, (meth)acryloyl isocyanate, allyl isocyanate, glycidyl (meth)acrylate, and (meth)acrylic acid.

[0181] The acrylic polymer is preferably a copolymer consisting of a (meth)acrylic monomer having a functional group such as a hydroxyl group, a carboxyl group, an amino group, a substituted amino group, or an epoxy group, or a derivative thereof, and another (meth)acrylic acid ester monomer copolymerizable therewith, or a derivative thereof.

[0182] Examples of (meth)acrylic monomers or derivatives thereof having a functional group such as a hydroxyl group, a carboxyl group, an amino group, a substituted amino group, or an epoxy group include 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate having a hydroxyl group; acrylic acid, methacrylic acid, and itaconic acid having a carboxyl group; and glycidyl methacrylate and glycidyl acrylate having an epoxy group.

[0183] Other (meth)acrylic acid ester monomers copolymerizable with the above-mentioned (meth)acrylic monomers or derivatives thereof include, for example, alkyl (meth)acrylates in which the alkyl group has 1 to 18 carbon atoms, and specific examples thereof include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. Examples of other (meth)acrylic acid ester monomers or derivatives thereof that are copolymerizable with the above (meth)acrylic monomer include (meth)acrylates having a cyclic skeleton, specifically cyclohexyl (meth)acrylate, benzyl (meth)acrylate, isobornyl acrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, imide acrylate, etc. In addition, the above acrylic polymer may be copolymerized with at least one selected from the group consisting of vinyl acetate, acrylonitrile, and styrene.

[0184] Even when an energy beam curable polymer is used, the above-mentioned energy beam polymerizable compound may be used in combination, and the binder polymer component (A) may also be used in combination. The relationship of the blending amounts of these three in the third pressure-sensitive adhesive layer in this embodiment is such that the energy beam polymerizable compound is preferably contained in an amount of 1 part by mass or more and 1500 parts by mass or less, more preferably 10 parts by mass or more and 500 parts by mass or less, and even more preferably 20 parts by mass or more and 200 parts by mass or less, per 100 parts by mass of the total mass of the energy beam curable polymer and the binder polymer component (A).

[0185] By imparting energy ray curing properties to the third adhesive layer, the third adhesive layer can be cured easily and in a short time, and the production efficiency of the chip with the cured adhesive layer is improved. The cured adhesive layer can also function as a protective film for protecting the semiconductor element. Conventionally, protective films for semiconductor elements such as chips have generally been formed from thermosetting resins such as epoxy resins, but the curing temperature of the thermosetting resin exceeds 200°C and the curing time is about 2 hours, which has been an obstacle to improving production efficiency. However, an energy ray curable adhesive layer is cured in a short time by energy ray irradiation, so that a protective film can be easily formed and can contribute to improving production efficiency.

[0186] Other Ingredients The third pressure-sensitive adhesive layer may contain the following components in addition to the binder polymer component (A) and the curable component (B).

[0187] (CX) Colorant In one embodiment, the third adhesive layer contains a colorant (CX). By blending a colorant into the third adhesive layer, when the third adhesive layer is cured to form a protective film for the semiconductor chip CP, the protective film can block infrared rays and the like generated from the surrounding equipment when the semiconductor device is incorporated into an apparatus, and can prevent malfunction of the semiconductor device due to the infrared rays and the like. In addition, the visibility of characters when a product number or the like is printed on the cured adhesive layer (protective film) obtained by curing the third adhesive layer containing the colorant (CX) is improved. That is, in a semiconductor device or semiconductor chip on which a protective film is formed, a product number or the like is usually printed on the surface of the protective film by a laser marking method (a method of scraping off the surface of the protective film with a laser beam and printing). By containing the colorant (CX) in the protective film, a sufficient contrast difference is obtained between the part of the protective film scraped off by the laser beam and the part of the protective film that is not scraped off, and the visibility is improved. As the colorant (CX), at least one of an organic pigment, an inorganic pigment, an organic dye, and an inorganic dye is used. The colorant (CX) is preferably a black pigment in terms of electromagnetic wave and infrared shielding properties. Examples of black pigments include, but are not limited to, carbon black, iron oxide, manganese dioxide, aniline black, and activated carbon. From the viewpoint of improving the reliability of the semiconductor device, the colorant (CX) is particularly preferably carbon black. The colorant (CX) may be used alone or in combination of two or more. The high curing property of the third adhesive layer in this embodiment is particularly preferably exhibited when a colorant that reduces the transmittance of at least one of visible light and infrared light and ultraviolet light is used, and the transmittance of ultraviolet light is reduced. The colorant that reduces the transmittance of at least one of visible light and infrared light and ultraviolet light is not particularly limited to the above black pigment, as long as it has absorptivity or reflectivity in the wavelength range of at least one of visible light and infrared light and ultraviolet light.

[0188] The amount of colorant (CX) is preferably 0.1 parts by mass or more and 35 parts by mass or less, more preferably 0.5 parts by mass or more and 25 parts by mass or less, and even more preferably 1 part by mass or more and 15 parts by mass or less, relative to 100 parts by mass of the total solid content constituting the third adhesive layer.

[0189] (D) Curing accelerator The curing accelerator (D) is used to adjust the curing speed of the third pressure-sensitive adhesive layer. The curing accelerator (D) is preferably used particularly when an epoxy resin and a thermosetting agent are used in combination in the curable component (B).

[0190] Preferred curing 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 tetraphenylboron salts such as tetraphenylphosphonium tetraphenylborate and triphenylphosphine tetraphenylborate. These curing accelerators can be used alone or in combination of two or more.

[0191] The curing accelerator (D) is preferably contained in an amount of 0.01 part by mass or more and 10 parts by mass or less, and more preferably 0.1 part by mass or more and 1 part by mass or less, per 100 parts by mass of the curable component (B).

[0192] (EX) Coupling agent The coupling agent (EX) may be used to improve at least one of the adhesion and adhesion of the third adhesive layer to the semiconductor element and the cohesion of the cured adhesive layer (protective film). In addition, by using the coupling agent (EX), the water resistance of the cured adhesive layer (protective film) obtained by curing the third adhesive layer can be improved without impairing the heat resistance of the cured adhesive layer (protective film).

[0193] As the coupling agent (EX), a compound having a group reactive with a functional group possessed by the binder polymer component (A), the curable component (B), etc. is preferably used. As the coupling agent (EX), a silane coupling agent is preferable. Examples of such coupling agents include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-(methacryloxypropyl)trimethoxysilane, γ-aminopropyltrimethoxysilane, N-6-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-6-(aminoethyl)-γ-aminopropylmethyldiethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, bis(3-triethoxysilylpropyl)tetrasulfane, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, imidazolesilane, etc. These coupling agents (EX) can be used alone or in combination of two or more.

[0194] The coupling agent (EX) is usually contained in an amount of 0.1 part by mass or more and 20 parts by mass or less, preferably 0.2 parts by mass or more and 10 parts by mass or less, and more preferably 0.3 parts by mass or more and 5 parts by mass or less, relative to 100 parts by mass in total of the binder polymer component (A) and the curable component (B).

[0195] (F) Inorganic filler By incorporating the inorganic filler (F) in the third adhesive layer, it becomes possible to adjust the thermal expansion coefficient of the cured adhesive layer (protective film) after curing.

[0196] Preferred inorganic fillers include silica, alumina, talc, calcium carbonate, titanium oxide, iron oxide, silicon carbide, and boron nitride powders, beads obtained by shaping these into spheres, single crystal fibers, and glass fibers. Among these inorganic fillers, silica filler and alumina filler are preferred. The inorganic filler (F) may be used alone or in combination of two or more. The content of the inorganic filler (F) can be adjusted within a range of usually 1 part by mass or more and 80 parts by mass or less based on 100 parts by mass of the total solid content constituting the adhesive layer.

[0197] (G) Photopolymerization initiator When the third pressure-sensitive adhesive layer contains an energy ray-curable component as the above-mentioned curable component (B), the energy ray-curable component is cured by irradiating it with energy rays such as ultraviolet rays when it is used. At this time, by including a photopolymerization initiator (G) in the composition constituting the third pressure-sensitive adhesive layer, the polymerization curing time can be shortened and the amount of light irradiation can be reduced.

[0198] 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 methyl benzoate, benzoin dimethyl ketal, 2,4-diethylthioxanthone, α-hydroxycyclohexyl phenyl ketone, benzyl diphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, 1,2-diphenylmethane, 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and β-chloroanthraquinone. The photopolymerization initiators (G) can be used alone or in combination of two or more.

[0199] The blending ratio of the photopolymerization initiator (G) is preferably 0.1 parts by mass or more and 10 parts by mass or less, and more preferably 1 part by mass or more and 5 parts by mass or less, relative to 100 parts by mass of the energy ray curable component. If the blending ratio of the photopolymerization initiator (G) is 0.1 parts by mass or more, it is possible to prevent a problem in which satisfactory transferability cannot be obtained due to insufficient photopolymerization. If the blending ratio of the photopolymerization initiator (G) is 10 parts by mass or less, it is possible to prevent a problem in which a residue that does not contribute to photopolymerization is generated, resulting in insufficient curability of the third adhesive layer.

[0200] (H) Crosslinking Agent In order to adjust the initial adhesive strength and cohesive strength of the third adhesive layer, a crosslinking agent can be added to the third adhesive layer. Examples of the crosslinking agent (H) include organic polyvalent isocyanate compounds and organic polyvalent imine compounds.

[0201] Examples of the organic polyisocyanate compound include aromatic polyisocyanate compounds, aliphatic polyisocyanate compounds, alicyclic polyisocyanate compounds, and trimers of these organic polyisocyanate compounds, as well as isocyanate-terminated urethane prepolymers obtained by reacting these organic polyisocyanate compounds with polyol compounds.

[0202] Examples of the organic polyisocyanate compound include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, diphenylmethane-4,4'-diisocyanate, diphenylmethane-2,4'-diisocyanate, 3-methyldiphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, trimethylolpropane adduct tolylene diisocyanate, and lysine isocyanate.

[0203] Examples of the organic polyvalent imine compound include N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinylpropionate, tetramethylolmethane-tri-β-aziridinylpropionate, and N,N'-toluene-2,4-bis(1-aziridinecarboxamide)triethylenemelamine.

[0204] The crosslinking agent (H) is usually used in a ratio of 0.01 part by mass or more and 20 parts by mass or less, preferably 0.1 part by mass or more and 10 parts by mass or less, and more preferably 0.5 part by mass or more and 5 parts by mass or less, relative to 100 parts by mass of the total amount of the binder polymer component (A) and the energy beam curable polymer.

[0205] (I) General purpose additives In addition to the above, the third pressure-sensitive adhesive layer may contain various additives as necessary, such as a leveling agent, a plasticizer, an antistatic agent, an antioxidant, an ion trapping agent, a gettering agent, and a chain transfer agent.

[0206] The third adhesive layer made of the above-mentioned components has adhesiveness and curing properties, and in an uncured state, it easily adheres to an object to be processed (such as a semiconductor wafer or chip) by pressing it against it. The third adhesive layer may have a single layer structure, or may have a multilayer structure as long as it includes at least one layer containing the above-mentioned components.

[0207] The thickness of the third pressure-sensitive adhesive layer is not particularly limited. The thickness of the third pressure-sensitive adhesive layer is preferably 3 μm or more and 300 μm or less, more preferably 5 μm or more and 250 μm or less, and even more preferably 7 μm or more and 200 μm or less.

[0208] The above is the explanation regarding the third adhesive layer.

[0209] Release sheet A release sheet may be attached to the surface of the composite sheet 130. Specifically, the release sheet is attached to the surface of the third adhesive layer of the composite sheet 130. The release sheet is attached to the surface of the third adhesive layer to protect the third adhesive layer during transportation and storage. The release sheet is releasably attached to the composite sheet 130, and is peeled off and removed from the composite sheet 130 before the composite sheet 130 is used.

[0210] The release sheet used is a release sheet having at least one surface subjected to a release treatment. Specifically, for example, the release sheet includes a release sheet substrate and a release agent layer formed by applying a release agent onto the surface of the substrate.

[0211] The release sheet substrate is preferably a resin film. Examples of the resin constituting the resin film as the release 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 release agent include rubber-based elastomers such as silicone-based resins, olefin-based resins, isoprene-based resins, and butadiene-based resins, long-chain alkyl-based resins, alkyd-based resins, and fluorine-based resins.

[0212] The thickness of the release sheet is not particularly limited, but is preferably 10 μm or more and 200 μm or less, and more preferably 20 μm or more and 150 μm or less.

[0213] [Effects of this embodiment] According to the expanding method of this embodiment, when the first sheet 10 is expanded, the back surface W3 of the semiconductor chip CP is not in contact with the first adhesive layer 12 of the first sheet 10. In each of the semiconductor chips CP, the protective layer 100A, which is individualized in the dicing process, is interposed between the back surface W3 and the first adhesive layer 12, so that the first adhesive layer 12 in contact with the back surface W3 is not stretched even when the first sheet 10 is expanded. As a result, according to the expanding method of this embodiment, it is possible to suppress adhesive residue. In addition, in this embodiment, in the dicing step, the semiconductor wafer W is supported not by a dicing sheet but by the composite sheet 130. Therefore, in order to form a layer for protecting the back surface W3 of the semiconductor chip CP after dicing (protective layer 100A in this embodiment), even if a step of replacing the adhesive sheet used in the dicing step with another adhesive sheet is not performed, the layer for protecting the back surface W3 can be formed by peeling between the protective layer 100A and the third sheet 30. Furthermore, before the expanding process is performed, the adhesive sheet used in the dicing process is replaced with an adhesive sheet for the expanding process, so there is no need to carefully control the cutting depth so that the dicing blade does not reach the base material of the dicing sheet during the dicing process. Therefore, according to the expanding method of this embodiment, the tape configuration and process can be simplified compared to conventional methods, and adhesive residue can be suppressed. Furthermore, it is possible to provide a method for manufacturing a semiconductor device including the expanding method according to this embodiment.

[0214] Third Embodiment Next, a third embodiment of the present invention will be described. The first and third embodiments differ mainly in the following points. In the first embodiment, a protective layer is provided on the first object surface (circuit surface W1) of the object (semiconductor wafer W), and after the dicing process, the dicing sheet (second adhesive sheet 20) is replaced with an expandable sheet (first sheet) before the expanding process. In contrast, in the third embodiment, a protective layer is provided on the object by attaching the second object surface (rear surface W3) of the object (semiconductor wafer W) to the protective layer of a composite sheet having the protective layer and the first sheet, and after the dicing process, the expanding process is performed without replacing the first sheet with another sheet. In the following description, differences from the first embodiment will be mainly described, and overlapping descriptions will be omitted or simplified. The same components as those in the first embodiment will be denoted by the same reference numerals, and descriptions thereof will be omitted or simplified.

[0215] The expanding method according to this embodiment includes the following steps (PY1) to (PY3). (PY1) A step of attaching an object to a protective layer of a composite sheet having a protective layer and a first sheet, the protective layer having substantially the same shape as the object. (PY2) A process in which a wafer is cut from the first workpiece surface side of the workpiece, and then at least the protective layer is cut to separate the wafer into a plurality of semiconductor devices. The first workpiece surface becomes the circuit surface of the semiconductor device, and the second workpiece surface becomes the back surface of the semiconductor device. (PY3) A process of expanding the first sheet to increase the spacing between the multiple semiconductor devices.

[0216] 8 (FIGS. 8A, 8B, and 8C) and 9 are schematic cross-sectional views illustrating a method for manufacturing a semiconductor device including an expanding method according to this embodiment.

[0217] (Composite sheet) FIG. 8A shows a schematic cross-sectional view of a composite sheet 140 used in this embodiment. The composite sheet 140 has a protective layer 100B and a first sheet 10. The composite sheet 140 holds the semiconductor wafer W when the semiconductor wafer W is diced, and holds the semiconductor chips CP when an expanding step is performed. The semiconductor wafer W is attached with the back surface W3 facing the protective layer 100B of the composite sheet 140. The first sheet 10 and the protective layer 100B to be attached to the back surface W3 are preferably a laminated composite sheet 140 that is laminated in advance.

[0218] (protective layer) The protective layer 100B in the composite sheet 140 is laminated on the first sheet 10. There are no particular limitations on the protective layer 100B as long as it can be attached to the back surface W3 (back surface of the semiconductor device) of the semiconductor chip CP as the semiconductor device and the semiconductor wafer W as the processing object to protect the back surface W3.

[0219] In this embodiment, the protective layer 100B has approximately the same shape as the back surface W3 of the semiconductor wafer W. The shape of the protective layer 100B is preferably a shape that can cover the back surface W3 of the semiconductor wafer W. Therefore, the protective layer 100B is preferably formed to be approximately the same as the back surface W3 of the semiconductor wafer W or slightly larger than the back surface W3. Moreover, protective layer 100B is preferably formed smaller in the plane direction of the sheet than first sheet 10. A jig such as a ring frame can be attached to a portion of first pressure-sensitive adhesive layer 12 of first sheet 10 where protective layer 100B is not laminated. The protective layer 100B according to this embodiment is made of a single layer. The protective layer 100B may be a sheet in which a plurality of layers are laminated. From the viewpoint of ease of control of light transmittance and manufacturing costs, the protective layer 100B is preferably made of a single layer. The thickness of the protective layer 100B is preferably 1 μm or more, and more preferably 5 μm or more. The thickness of the protective layer 100B is preferably 500 μm or less, and more preferably 300 μm or less. The protective layer 100B may be, for example, a protective film or a protective sheet. The protective layer 100B may be, for example, a protective layer similar to the protective layer 100 described in the first embodiment. Another preferred embodiment of the protective layer 100B will be described later.

[0220] (1st sheet) The first sheet 10 in the composite sheet 140 is a member that supports the protective layer 100B. The material of the first sheet 10 is not particularly limited as long as it can support the protective layer 100B. The first sheet 10 in the composite sheet 140 has a first pressure-sensitive adhesive layer 12 and a first base material 11. The first sheet 10 is similar to the first sheet 10 in the first embodiment. In this embodiment, when the first sheet 10 is made of a material that can be peeled off from the protective layer 100B, the first sheet 10 can be peeled off while leaving the protective layer 100B on the rear surface W3 of the semiconductor chip CP.

[0221] [Composite sheet attachment process] Fig. 8B is a diagram for explaining the step (PY1). Fig. 8B shows a semiconductor wafer W to which a composite sheet 140 having a first sheet 10 and a protective layer 100B is attached. The semiconductor wafer W in this embodiment is also preferably a wafer obtained by going through a back grinding step. This step (PY1) may be referred to as a composite sheet attachment step. As described later, in a step (PY2), the semiconductor wafer W is diced into a plurality of semiconductor chips CP. In this embodiment, when the semiconductor wafer W is diced, a composite sheet 140 is attached to the back surface W3 in order to hold the semiconductor wafer W. The semiconductor wafer W is attached with the back surface W3 facing the protective layer 100B of the composite sheet 140. The protective layer 100B is formed in substantially the same shape as the back surface W3, and therefore can cover the back surface W3. In this embodiment, the protective layer 100B is sandwiched between the semiconductor wafer W and the first sheet 10.

[0222] In this embodiment, an example is described in which the process is carried out with the circuit surface W1 exposed. Other examples include, for example, a process in which a protective member such as a protective sheet or protective film separate from the protective layer 100B is attached to the circuit surface W1.

[0223] The process of adhering the first sheet 10 and the protective layer 100B to the back surface W3 is not limited to the embodiment using a laminated composite sheet 140, and may be, for example, an embodiment in which the protective layer 100B is adhered to the back surface W3 of the semiconductor wafer W, and then the first sheet 10 is bonded to the protective layer 100B.

[0224] [Dicing process] 8C is a diagram for explaining the step (PY2). The step (PY2) may be referred to as a dicing step. In FIG. 8C, a plurality of semiconductor chips CP held on the first sheet 10 are shown. The semiconductor wafer W with the first sheet 10 and the protective layer 100B attached to the rear surface W3 is divided into individual pieces by dicing, and a plurality of semiconductor chips CP are formed. In this embodiment, a cut is made from the circuit surface W1 side to cut the semiconductor wafer W, then the protective layer 100B is cut, and the cut is made to reach the first adhesive layer 12. By this dicing, the protective layer 100B is also cut to the same size as the semiconductor chips CP. The cutting depth during dicing is not particularly limited as long as the semiconductor wafer W and the protective layer 100B can be individually divided. In this embodiment, an example in which the incision is not made to the first base material 11 is described, but the present invention is not limited to such an example. For example, in another embodiment, from the viewpoint of more reliably cutting the semiconductor wafer W and the protective layer 100B, the incision may be made by dicing to a depth reaching the first base material 11. Also, the protective layer 100B may be cut without the incision reaching the first adhesive layer 12.

[0225] In this embodiment, the dicing process results in a laminated structure in which individualized protective layers 100B are interposed between multiple semiconductor chips CP and the first adhesive layer 12 of the first sheet 10 on the back surface W3 side of the semiconductor chip CP.

[0226] [Expanding process] Fig. 9 is a diagram for explaining the step (PY3). The step (PY3) may be referred to as an expanding step. Fig. 9 shows a state in which the first sheet 10 is expanded after the dicing step to expand the intervals between the multiple semiconductor chips CP. In the expanding step in this embodiment, the method of stretching the first sheet 10 is the same as in the first embodiment. In this embodiment, the spacing D1 between the multiple semiconductor chips CP is not particularly limited because it depends on the size of the semiconductor chips CP. The spacing D1 between adjacent semiconductor chips CP is preferably 200 μm or more. The upper limit of the spacing between the semiconductor chips CP is not particularly limited. The upper limit of the spacing between the semiconductor chips CP may be, for example, 6000 μm.

[0227] [Transfer process, sealing process and other processes] In this embodiment, as in the first or second embodiment, a transfer step, a sealing step, and other steps (a rewiring layer forming step and a connection step with external terminal electrodes) may be performed.

[0228] (protective layer) In one embodiment, the protective layer 100B is preferably formed from an uncured curable adhesive. In this case, after a processing object (workpiece) such as a semiconductor wafer W is placed on the protective layer 100B, the protective layer 100B is cured, so that the cured product (protective film) of the protective layer 100B can be firmly bonded to the processing object, and a durable protective film can be formed for a semiconductor device such as a semiconductor chip CP.

[0229] It is preferable that the protective layer 100B has adhesiveness at room temperature or exhibits adhesiveness when heated. This allows the protective layer 100B to be bonded to an object to be processed, such as a semiconductor wafer W, when the protective layer 100B is overlaid on the object to be processed, as described above. Therefore, positioning of the protective layer 100B can be reliably performed before the protective layer 100B is cured.

[0230] The curable adhesive constituting the protective layer 100B having the above-mentioned characteristics preferably contains a curable component and a binder polymer component. As the curable component, a thermosetting component, an energy ray curable component, or a mixture thereof can be used, but it is particularly preferable to use a thermosetting component. That is, the protective layer 100B is preferably composed of a thermosetting adhesive.

[0231] Examples of the thermosetting component include epoxy resins, phenol resins, melamine resins, urea resins, polyester resins, urethane resins, acrylic resins, polyimide resins, benzoxazine resins, and mixtures thereof. Among these, epoxy resins, phenol resins, and mixtures thereof are preferably used as the thermosetting component.

[0232] Epoxy resins have the property of forming a three-dimensional network and a strong coating when heated. As such epoxy resins, various epoxy resins known in the art are used. Usually, epoxy resins having a number average molecular weight of about 300 to 2000 are preferred, and epoxy resins having a number average molecular weight of 300 to 500 are more preferred. Furthermore, it is preferred to use a blend type epoxy resin obtained by blending an epoxy resin having a number average molecular weight of 330 to 400 that is liquid under normal conditions with an epoxy resin having a number average molecular weight of 400 to 2500 (preferably a number average molecular weight of 500 to 2000) that is solid at room temperature. In addition, the epoxy equivalent of the epoxy resin is preferably 50 g / eq to 5000 g / eq. In addition, the number average molecular weight of the epoxy resin can be determined by a method using a GPC method.

[0233] Specific examples of such epoxy resins include glycidyl ethers of phenols such as bisphenol A, bisphenol F, resorcinol, phenyl novolac, and cresol novolac; glycidyl ethers of alcohols such as butanediol, polyethylene glycol, and polypropylene glycol; glycidyl ethers of carboxylic acids such as phthalic acid, isophthalic acid, and tetrahydrophthalic acid; glycidyl or alkyl glycidyl epoxy resins in which active hydrogen bonded to nitrogen atoms such as aniline isocyanurate is substituted with a glycidyl group; and so-called alicyclic epoxides in which epoxy is introduced by, for example, oxidizing carbon-carbon double bonds in the molecule, such as vinylcyclohexane diepoxide, 3,4-epoxycyclohexylmethyl-3,4-dicyclohexanecarboxylate, and 2-(3,4-epoxy)cyclohexyl-5,5-spiro(3,4-epoxy)cyclohexane-m-dioxane. In addition, epoxy resins having at least one skeleton selected from the group consisting of, for example, a biphenyl skeleton, a dicyclohexadiene skeleton, and a naphthalene skeleton can also be used.

[0234] Among these specific examples of epoxy resins, bisphenol-based glycidyl epoxy resins, o-cresol novolac epoxy resins, and phenol novolac epoxy resins are preferably used as the epoxy resins. These epoxy resins can be used alone or in combination of two or more.

[0235] When epoxy resin is used, it is preferable to use a heat-activated latent epoxy resin curing agent as an auxiliary. A heat-activated latent epoxy resin curing agent is a type of curing agent that does not react with epoxy resin at room temperature, but is activated by heating above a certain temperature and reacts with epoxy resin. There are several methods for activating a heat-activated latent epoxy resin curing agent, including a method in which active species (anions, cations) are generated by a chemical reaction caused by heating; a method in which the agent is stably dispersed in epoxy resin near room temperature and becomes compatible and dissolved with epoxy resin at high temperatures to start a curing reaction; a method in which a molecular sieve-encapsulated type curing agent is dissolved at high temperatures to start a curing reaction; and a method using microcapsules.

[0236] Specific examples of the heat-activated latent epoxy resin curing agent include various onium salts, dibasic acid dihydrazide compounds, dicyandiamide, amine adduct curing agents, high melting point active hydrogen compounds such as imidazole compounds, etc. These heat-activated latent epoxy resin curing agents can be used alone or in combination of two or more. The heat-activated latent epoxy resin curing agent as described above is preferably used in an amount of 0.1 to 20 parts by weight, more preferably 0.2 to 10 parts by weight, and even more preferably 0.3 to 5 parts by weight, based on 100 parts by weight of the epoxy resin.

[0237] The phenol-based resin may be, without particular limitation, a condensate of a phenol such as an alkylphenol, a polyhydric phenol, or naphthol with an aldehyde, etc. Specifically, for example, a phenol novolac resin, an o-cresol novolac resin, a p-cresol novolac resin, a t-butylphenol novolac resin, a dicyclopentadiene cresol resin, a polyparavinylphenol resin, a bisphenol A type novolac resin, or a modified product thereof may be used.

[0238] The phenolic hydroxyl groups contained in these phenolic resins can easily undergo addition reaction with the epoxy groups of the epoxy resins by heating to form a cured product with high impact resistance, so that epoxy resins and phenolic resins may be used in combination as the thermosetting component.

[0239] The binder polymer component can provide the protective layer 100B with an appropriate tackiness. The weight average molecular weight (Mw) of the binder polymer is usually in the range of 50,000 to 2,000,000, preferably 100,000 to 1,500,000, and more preferably 200,000 to 1,000,000. If the molecular weight is too low, the film formation of the protective layer 100B becomes insufficient, and if it is too high, the compatibility with other components becomes poor, resulting in the prevention of uniform film formation. As such a binder polymer component, for example, at least one resin selected from the group consisting of acrylic polymers, polyester resins, phenoxy resins, urethane resins, silicone resins, and rubber-based polymers is used, and in particular, acrylic polymers are preferably used.

[0240] Examples of acrylic polymers include (meth)acrylic acid ester copolymers consisting of a (meth)acrylic acid ester monomer and a structural unit derived from a (meth)acrylic acid derivative. Here, as the (meth)acrylic acid ester monomer, a (meth)acrylic acid alkyl ester having an alkyl group with 1 to 18 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, and butyl (meth)acrylate, is preferably used. In addition, examples of (meth)acrylic acid derivatives include (meth)acrylic acid, glycidyl (meth)acrylate, and hydroxyethyl (meth)acrylate.

[0241] Among the above, when glycidyl groups are introduced into the acrylic polymer using glycidyl methacrylate or the like as a structural unit, the compatibility with the epoxy resin as the thermosetting component described above is improved, the glass transition temperature (Tg) of the protective layer 100B after curing is increased, and the heat resistance is improved. Also, among the above, when hydroxyl groups are introduced into the acrylic polymer using hydroxyethyl acrylate or the like as a structural unit, the adhesion to the object to be processed and the adhesive properties can be controlled.

[0242] When an acrylic polymer is used as the binder polymer, the weight average molecular weight (Mw) of the polymer is preferably 100,000 or more, more preferably 150,000 or more and 1,000,000 or less. The glass transition temperature of the acrylic polymer is usually 20° C. or less, preferably about −70° C. to 0° C., and the acrylic polymer has adhesiveness at room temperature (23° C.).

[0243] The blending ratio of the thermosetting component and the binder polymer component is preferably 50 to 1500 parts by weight, more preferably 70 to 1000 parts by weight, and even more preferably 80 to 800 parts by weight, per 100 parts by weight of the binder polymer component. Blending the thermosetting component and the binder polymer component at such a ratio provides a suitable tack before curing, allowing stable application, and provides a protective film with excellent coating strength after curing.

[0244] The protective layer 100B preferably contains at least one of a colorant and a filler, and more preferably contains both a colorant and a filler.

[0245] As the colorant, for example, known colorants such as inorganic pigments, organic pigments, and organic dyes can be used, but from the viewpoint of improving the controllability of light transmittance, it is preferable that the colorant contains an organic colorant. From the viewpoint of improving the chemical stability of the colorant (specifically, examples include resistance to elution, resistance to color transfer, and little change over time), it is preferable that the colorant is made of a pigment.

[0246] Examples of the filler include silica such as crystalline silica, fused silica, and synthetic silica, and inorganic fillers such as alumina and glass balloons. Among these inorganic fillers, silica is preferred as the filler, synthetic silica is more preferred, and synthetic silica of the type in which the source of alpha rays that causes malfunction of semiconductor devices is removed as much as possible is preferred. The shape of the filler can be spherical, acicular, or amorphous, with spherical being preferred, and true sphere being more preferred.

[0247] The protective layer 100B may contain a coupling agent. By containing a coupling agent, after the protective layer 100B is cured, the adhesiveness and adhesion between the protective film and the object to be processed can be improved without impairing the heat resistance of the protective film, and the water resistance (moisture and heat resistance) can be improved. As the coupling agent, a silane coupling agent is preferable because of its versatility and cost benefits.

[0248] Examples of silane coupling agents include γ-glycidoxypropyl trimethoxysilane, γ-glycidoxypropyl methyl diethoxysilane, β-(3,4-epoxycyclohexyl)ethyl trimethoxysilane, γ-(methacryloxypropyl) trimethoxysilane, γ-aminopropyl trimethoxysilane, N-6-(aminoethyl)-γ-aminopropyl trimethoxysilane, N-6-(aminoethyl)-γ-aminopropyl methyl diethoxysilane, N-phenyl-γ-aminopropyl trimethoxysilane, γ-ureidopropyl triethoxysilane, γ-mercaptopropyl trimethoxysilane, γ-mercaptopropyl methyl dimethoxysilane, bis(3-triethoxysilylpropyl)tetrasulfane, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, imidazole silane, etc. As the silane coupling agent, one of these silane coupling agents can be used alone, or two or more can be mixed together.

[0249] The protective layer 100B may contain a crosslinking agent such as an organic polyisocyanate compound, an organic polyimine compound, or an organic metal chelate compound in order to adjust the cohesive force before curing. The protective layer 100B may also contain an antistatic agent in order to suppress static electricity and improve the reliability of the chip. Furthermore, the protective layer 100B may contain a flame retardant such as a phosphoric acid compound, a bromine compound, or a phosphorus compound in order to increase the flame retardant performance of the protective film and improve the reliability of the package.

[0250] The thickness of the protective layer 100B is not particularly limited. When the protective layer 100B is cured and used as a protective film, in order to effectively exhibit the function as a protective film, the thickness of the protective layer 100B is preferably 3 μm or more and 300 μm or less, more preferably 5 μm or more and 200 μm or less, and further preferably 7 μm or more and 100 μm or less.

[0251] [Effects of this embodiment] According to the expanding method of this embodiment, when the first sheet 10 is expanded, the back surface W3 of the semiconductor chip CP is not in contact with the first adhesive layer 12 of the first sheet 10. In each of the semiconductor chips CP, the protective layer 100B, which has been diced in the dicing process, is interposed between the back surface W3 and the first adhesive layer 12, so that the protective layer 100B in contact with the back surface W3 is not stretched even when the first sheet 10 is expanded. As a result, according to the expanding method of this embodiment, it is possible to suppress adhesive residue. Furthermore, in this embodiment, the protective layer 100B has approximately the same shape as the back surface W3 of the semiconductor wafer W, and the protective layer 100B is also diced into individual pieces for the back surfaces W3 of the semiconductor chips CP (semiconductor chips on the outer periphery) formed originating from the edge side of the semiconductor wafer W by dicing, so that the spacing between the semiconductor chips CP can be sufficiently expanded.

[0252] Furthermore, in this embodiment, during the dicing step, the semiconductor wafer W is supported not by a dicing sheet, but by a composite sheet 140 having the first sheet 10 and the protective layer 100B. Therefore, in order to form a layer for protecting the rear surface W3 of the semiconductor chip CP after dicing (protective layer 100B in this embodiment), it is not necessary to perform a step of replacing the adhesive sheet used in the dicing step with another adhesive sheet, and the process can be simplified. Furthermore, before performing the expanding step, it is not necessary to replace the adhesive sheet used in performing the dicing step with an adhesive sheet for the expanding step. Therefore, according to the expanding method of this embodiment, the process is simplified compared to conventional methods, and the gap between the chips can be sufficiently expanded while suppressing glue residue. Furthermore, it is possible to provide a method for manufacturing a semiconductor device including the expanding method according to this embodiment.

[0253] [Modifications of the embodiment] The present invention is not limited to the above-described embodiment, and includes modifications of the above-described embodiment within the scope of the invention.

[0254] For example, circuits in a semiconductor wafer or a semiconductor chip are not limited to the arrangement or shape shown in the drawings. A connection structure with an external terminal electrode in a semiconductor package is also not limited to the aspects described in the above-mentioned embodiment. Although the above-mentioned embodiment has been described by taking as an example an aspect of manufacturing a FO-WLP type semiconductor package, the present invention can also be applied to an aspect of manufacturing other semiconductor packages such as a fan-in type WLP.

[0255] In the above-mentioned method for manufacturing an FO-WLP, some steps may be changed or some steps may be omitted.

[0256] The dicing in the dicing step may be performed by irradiating the semiconductor wafer with a laser beam instead of using the above-mentioned cutting means. For example, the semiconductor wafer may be completely divided by irradiation with a laser beam, and divided into a plurality of semiconductor chips. In these methods, the laser beam may be irradiated from either side of the semiconductor wafer.

[0257] In the second embodiment, the composite sheet 130 is described as having the protective layer 100A and the third sheet 30, or the protective layer 100A is the third adhesive layer and the third sheet 30 is the third substrate, but the present invention is not limited to these embodiments. For example, the composite sheet 130 may be an adhesive sheet having a release layer between the third adhesive layer and the third substrate. The release layer is preferably made of the same material as the release sheet described in the first embodiment. EXAMPLES

[0258] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples in any way.

[0259] (Preparation of adhesive sheet) [Example 1] An acrylic copolymer was obtained by copolymerizing 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). A solution of a resin (acrylic A) (adhesive base, solid content 35.0% by mass) was prepared by adding 2-isocyanatoethyl methacrylate (manufactured by Showa Denko K.K., product name "Karens MOI" (registered trademark)) to this acrylic copolymer. The addition ratio was 90 mol % of 2-isocyanatoethyl methacrylate to 100 mol % of 2HEA in the acrylic copolymer. The weight average molecular weight (Mw) of the obtained resin (acrylic A) was 600,000, and Mw / Mn was 4.5. The weight average molecular weight Mw and number average molecular weight Mn in terms of standard polystyrene were measured by gel permeation chromatography (GPC), and the molecular weight distribution (Mw / Mn) was calculated from each measured value. To this adhesive base, UV resin A (10-functional urethane acrylate, manufactured by Mitsubishi Chemical Corporation, product name "UV-5806", Mw=1740, containing a photopolymerization initiator) and a tolylene diisocyanate-based crosslinking agent (manufactured by Nippon Polyurethane Industry Co., Ltd., product name "Coronate L") were added as a crosslinking agent. 50 parts by mass of UV resin A and 0.2 parts by mass of the crosslinking agent were added relative to 100 parts by mass of the solid content in the adhesive base. After the addition, the mixture was stirred for 30 minutes to prepare adhesive composition A1. Next, the solution of the prepared adhesive composition A1 was applied to a polyethylene terephthalate (PET)-based release film (manufactured by Lintec Corporation, product name "SP-PET381031", thickness 38 μm) and dried to form a 40 μm-thick adhesive layer on the release film. A polyester-based polyurethane elastomer sheet (manufactured by Seedam Co., Ltd., product name "Higress DUS202", thickness 100 μm) was bonded to the adhesive layer as a substrate, and unnecessary portions of the edges in the width direction were cut off to produce adhesive sheet SA1.

[0260] (Method of measuring tip spacing) The pressure-sensitive adhesive sheet obtained in Example 1 was cut to a size of 210 mm x 210 mm to obtain a test sheet, such that each side of the cut sheet was parallel or perpendicular to the MD direction of the substrate in the pressure-sensitive adhesive sheet. The semiconductor chips to be attached to the adhesive sheet were prepared by the following procedure. A sheet serving as a protective layer (sometimes referred to as a protective sheet in the examples) was attached to a 6-inch silicon wafer. As the protective sheet, "E-3125KL" (product name) manufactured by Lintec Corporation was used. Next, the 6-inch silicon wafer was diced from the protective sheet side, and a total of 25 chips, each 3 mm x 3 mm in size, were cut out in five rows in the X-axis direction and five rows in the Y-axis direction. A diced protective sheet was attached to each of the chips. The release film of the test sheet was peeled off, and the protective sheet side of the 25 chips cut out as described above was attached to the center of the exposed adhesive layer. At this time, the chips were arranged in 5 rows in the X-axis direction and 5 rows in the Y-axis direction.

[0261] Next, the test sheet with the chips attached was placed in a biaxially stretchable expanding device (separating device). FIG. 10 shows a plan view illustrating the expanding device 400. In FIG. 10, the X-axis and the Y-axis are perpendicular to each other, and the positive direction of the X-axis is the +X-axis direction, the negative direction of the X-axis is the -X-axis direction, the positive direction of the Y-axis is the +Y-axis direction, and the negative direction of the Y-axis is the -Y-axis direction. The test sheet 500 was placed in the expanding device 400 so that each side was parallel to the X-axis or Y-axis. As a result, the MD direction of the substrate in the test sheet 500 is parallel to the X-axis or Y-axis. Note that the chips are omitted in FIG. 10.

[0262] 10, the expanding device 400 includes five holding means 401 in each of the +X-axis direction, the -X-axis direction, the +Y-axis direction, and the -Y-axis direction (a total of 20 holding means 401). Of the five holding means 401 in each direction, the holding means 401A are located at both ends, the holding means 401C is located in the center, and the holding means 401B is located between the holding means 401A and the holding means 401C. Each side of the test sheet 500 was gripped by these holding means 401.

[0263] 10, one side of the test sheet 500 is 210 mm. The distance between the holding means 401 on each side is 40 mm. The distance between the end of one side of the test sheet 500 (the apex of the sheet) and the holding means 401A on that side that is closest to that end is 25 mm.

[0264] Next, a plurality of tension applying means (not shown) corresponding to each of the holding means 401 were driven to move each of the holding means 401 independently. The four sides of the test sheet were fixed with a gripping jig, and the test sheet was expanded by an expansion amount of 200 mm at a speed of 5 mm / s in each of the X-axis direction and the Y-axis direction. After that, the expanded state of the test sheet 500 was maintained by a ring frame. While the expanded state was maintained, the distance between each tip was measured using a digital microscope, and the average value of the distance between each tip was taken as the tip interval. If the chip spacing was 1800 μm or more, it was judged as passing "A", and if the chip spacing was less than 1800 μm, it was judged as failing "B".

[0265] (Method of measuring chip alignment) The deviation rates from the center lines of adjacent tips in the X-axis and Y-axis directions of the workpiece for which the tip intervals were measured were then measured. FIG. 11 shows a schematic diagram of a specific measurement method. A row of five chips arranged in the X-axis direction was selected, and the distance Dy between the top end of the chip and the bottom end of the chip in the row was measured using a digital microscope. The deviation rate in the Y-axis direction was calculated based on the following formula (Equation 3). Sy is the chip size in the Y-axis direction, which was set to 3 mm in this embodiment. Deviation rate in the Y-axis direction [%] = [(Dy-Sy) / 2] / Sy x 100… (Equation 3) The deviation rates in the Y-axis direction were calculated in the same manner for the other four rows in which five chips were arranged in the X-axis direction. A row of five chips arranged in the Y-axis direction was selected, and the distance Dx between the leftmost end of the chip and the rightmost end of the chip in the row was measured using a digital microscope. The deviation rate in the X-axis direction was calculated based on the following formula (Math. 4). Sx is the chip size in the X-axis direction, and in this embodiment, it was set to 3 mm. Deviation rate in the X-axis direction [%] = [(Dx-Sx) / 2] / Sx x 100… (Equation 4) The deviation rates in the X-axis direction were calculated in the same manner for the other four rows, each having five chips lined up in the Y-axis direction. In the formulas (3) and (4), the reason for dividing by 2 is to express the maximum distance that the tip deviates from the predetermined position after expansion in an absolute value. If the deviation rate was less than ±10% in all columns in the X-axis and Y-axis directions (10 columns in total), it was judged as a pass (A), and if it was more than ±10% in one or more columns, it was judged as a fail (B).

[0266] (Method for evaluating adhesive residue) After expanding under the conditions described in the above-mentioned chip interval measurement method, an ultraviolet ray irradiation device ("RAD-2000 m / 12" manufactured by Lintec Corporation) was used to irradiate the adhesive sheet according to Example 1 from the side opposite to the side on which the chips were mounted with an illuminance of 220 mW / cm 2 , light intensity 460mJ / cm 2 After UV irradiation, the chip was held on a suction table and the adhesive sheet was peeled off. After the adhesive sheet was peeled off, the chip surface to which the adhesive sheet had been attached was observed under an optical microscope. If no adhesive residue was observed on the chip surface, it was judged as passing "A", and if adhesive residue was observed, it was judged as failing "B".

[0267] When the adhesive sheet according to Example 1 was used for expansion, the evaluation result for the chip spacing was rated as pass "A", and the evaluation result for the chip alignment was rated as pass "A". When a protective sheet was placed between the chip and the adhesive sheet of the example and the adhesive sheet was expanded, the adhesive residue evaluation result on the chip surface was rated as "A", which is acceptable. [Explanation of symbols]

[0268] 10...first sheet, 100, 100A, 100B...protective layer, 11...first substrate, 12...first adhesive layer, 130, 140...composite sheet, 20...second adhesive sheet, W...semiconductor wafer (object to be processed), W1...circuit surface (first semiconductor device surface), W3...reverse surface (second semiconductor device surface).

Claims

1. The method includes a step of expanding a first sheet to which a plurality of semiconductor devices are attached, thereby expanding a space between the plurality of semiconductor devices; each of the plurality of semiconductor devices has a first semiconductor device surface and a second semiconductor device surface opposite the first semiconductor device surface; Each of the plurality of semiconductor devices is attached to the first sheet with a protective layer between the first semiconductor device surface or the second semiconductor device surface, The protective layer is formed on the object to be processed, The object to be processed on which the protective layer is formed is attached to a second adhesive layer of a second adhesive sheet having a second adhesive layer and a second base material; dicing the protective layer and the object to be processed to obtain the plurality of semiconductor devices; The first sheet is attached to the protective layer after dicing; The protective layer is a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer and a substrate. Expand method.

2. In the expanding method according to claim 1, The first sheet is attached to the protective layer after dicing, and then the second adhesive sheet is peeled off. Expand method.

3. In the expanding method according to claim 1 or 2, The workpiece is a semiconductor wafer. Expand method.

4. In the expanding method according to any one of claims 1 to 3, The first sheet is an expandable sheet. Expand method.

5. In the expanding method according to any one of claims 1 to 4, the first semiconductor device surface having circuitry; Expand method.

6. A method for manufacturing a semiconductor device, comprising the expanding method according to any one of claims 1 to 5.

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