CN113366080A

CN113366080A - Method for expanding wafer and method for manufacturing semiconductor device

Info

Publication number: CN113366080A
Application number: CN202080011754.0A
Authority: CN
Inventors: 布施启示; 稻男洋一; 山田忠知
Original assignee: Lintec Corp
Current assignee: Lintec Corp
Priority date: 2019-01-31
Filing date: 2020-01-29
Publication date: 2021-09-07
Anticipated expiration: 2040-01-29
Also published as: CN113366080B; WO2020158766A1; TW202044384A; KR20210123318A; JPWO2020158766A1

Abstract

The invention provides a method for expanding a wafer, which comprises the following steps: and a step of extending the 1 st sheet (10) to which the plurality of semiconductor devices (CP) are bonded so as to widen the intervals between the plurality of semiconductor devices (CP), wherein each of the plurality of semiconductor devices (CP) has a1 st semiconductor device surface (W1) and a 2 nd semiconductor device surface (W3) on the opposite side of the 1 st semiconductor device surface (W1), and the plurality of semiconductor devices (CP) are bonded together with a protective layer (100) interposed between the 2 nd semiconductor device surface (W3) and the 1 st sheet (10).

Description

Method for expanding wafer and method for manufacturing semiconductor device

Technical Field

The present invention relates to a method of expanding a wafer and a method of manufacturing a semiconductor device.

Background

In recent years, electronic devices have been increasingly downsized, lightened, and highly functional. Semiconductor devices mounted in electronic devices are also required to be miniaturized, thinned, and densified. A semiconductor chip is sometimes mounted on a package having a size close to that of the semiconductor chip. Such packages are sometimes also referred to as Chip Scale Packages (CSPs). One of the CSPs is a Wafer Level Package (WLP). In WLP, external electrodes and the like are formed on a wafer before singulation by dicing, and the wafer is finally diced and singulated. Examples of WLP include a Fan-In (Fan-In) type and a Fan-Out (Fan-Out) type. In fan-out WLP (hereinafter, also referred to as "FO-WLP" for short), a semiconductor chip is covered with a sealing material in a region larger than the chip size to form a semiconductor chip package, and a rewiring layer and external electrodes are formed not only on the circuit surface of the semiconductor chip but also in the surface region of the sealing material.

For example, patent document 1 describes a method for manufacturing a semiconductor package, the method including: a plurality of semiconductor chips formed by singulating a semiconductor wafer are surrounded by a mold member with circuit forming surfaces thereof left, to form an expanded wafer, and a rewiring pattern is extended to a region outside the semiconductor chips to form a semiconductor package. In the manufacturing method described in patent document 1, before the plurality of singulated semiconductor chips are surrounded by the mold member, a wafer mounting tape for spreading is transferred to the mold member, and the wafer mounting tape is spread to increase the distance between the plurality of semiconductor chips.

Patent document 2 describes an adhesive sheet comprising a second base material layer, a first base material layer, and a first adhesive layer in this order, wherein the second base material layer has an elongation at break of 400% or more. The method for manufacturing a semiconductor device described in patent document 2 includes: a step of bonding a semiconductor wafer to the first adhesive layer of the adhesive sheet; a step of forming a plurality of semiconductor chips by dicing the semiconductor wafer into individual pieces; and stretching the adhesive sheet to expand the interval between the semiconductor chips.

Documents of the prior art

Patent document

Patent document 1: international publication No. 2010/058646

Patent document 2: japanese patent laid-open publication No. 2017-076748

Disclosure of Invention

Problems to be solved by the invention

The tape used in the tape-out step generally has an adhesive layer for fixing the semiconductor chip on the tape and a base material for supporting the adhesive layer. When the wafer-bonding tape for expansion is stretched as described in patent document 1, not only the tape base material but also the adhesive layer are stretched. When the semiconductor chip is peeled off from the adhesive layer after the spreading step, the adhesive layer may remain on the surface of the semiconductor chip in contact with the adhesive layer. In the present specification, such a defect is sometimes referred to as glue residue.

When the sheet expanding step is performed using the pressure-sensitive adhesive sheet described in patent document 2, it is considered that the pressure-sensitive adhesive layer bonded to the semiconductor chip is not stretched, and therefore, adhesive residue is less likely to occur. However, the pressure-sensitive adhesive sheet described in patent document 2 has a tape structure in which the second base material layer, the first base material layer, and the first pressure-sensitive adhesive layer are laminated, and therefore, there is a demand for a sheet expansion method capable of preventing adhesive residue by adopting a simpler tape structure. In the process described in patent document 2, the semiconductor wafer on the adhesive sheet is diced, and the adhesive sheet is stretched without being transferred to another adhesive sheet, and the sheet expanding step is performed. Therefore, the depth of the cut mark of the dicing blade needs to be carefully controlled so that the dicing blade at the time of dicing does not reach the second base material layer, and thus there is also a demand for a sheet expanding method capable of preventing the cull with a simpler method.

In the die-expanding method, the adherend supported on the pressure-sensitive adhesive sheet includes not only a semiconductor chip but also, for example, a wafer, a semiconductor device package, and a semiconductor device such as a micro LED. As with the semiconductor chips, these semiconductor devices may have a wider gap therebetween.

The invention provides a method for expanding a semiconductor wafer, which can simplify at least one of a tape structure and a process compared with the prior art and can restrain residual glue, and a method for manufacturing a semiconductor device comprising the method for expanding the wafer.

Means for solving the problems

According to an embodiment of the present invention, there may be provided a method of expanding a sheet, the method including: and stretching a1 st sheet to which a plurality of semiconductor devices are bonded, the plurality of semiconductor devices each having a1 st semiconductor device surface and a 2 nd semiconductor device surface opposite to the 1 st semiconductor device surface, to expand an interval between the plurality of semiconductor devices, the plurality of semiconductor devices being bonded to the 1 st sheet with a protective layer interposed therebetween.

In the film expanding method according to one aspect of the present invention, it is preferable that the plurality of semiconductor devices are bonded to the 1 st piece after the protective layer is formed on the 1 st semiconductor device surface.

In the expanding method according to one aspect of the present invention, the plurality of semiconductor devices are preferably obtained by dicing the object to be processed.

In the film expanding method according to one aspect of the present invention, it is preferable that the protective layer is formed on the object, and the object and the protective layer are diced to obtain the plurality of semiconductor devices.

In the expanding method according to one aspect of the present invention, it is preferable that the object to be processed on which the protective layer is formed is bonded to the 2 nd adhesive layer of a 2 nd adhesive sheet having a 2 nd adhesive layer and a 2 nd base material, the protective layer and the object to be processed are cut to obtain the plurality of semiconductor devices, and the 1 st sheet is bonded to the protective layer after the cutting.

In the sheet expanding method according to one embodiment of the present invention, it is preferable that the 2 nd adhesive sheet is peeled after the 1 st sheet is bonded to the cut protective layer.

In the film expanding method according to one aspect of the present invention, it is preferable that the object to be processed is bonded to the protective layer of a composite sheet including the protective layer and a 3 rd sheet, the object to be processed and the protective layer are diced to obtain the plurality of semiconductor devices, and the 3 rd sheet is peeled off from the protective layer.

In the film expanding method according to one aspect of the present invention, it is preferable that the protective layer and the 1 st 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 plurality of semiconductor devices.

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

In the sheet expanding method according to one embodiment of the present invention, the 1 st sheet is preferably an expanded sheet.

In the film expanding method according to one aspect of the present invention, it is preferable that the 1 st semiconductor device has a circuit on a surface thereof.

According to one embodiment of the present invention, there is provided a method for manufacturing a semiconductor device including the wafer expanding method according to one embodiment of the present invention.

According to one embodiment of the present invention, a sheet expanding method is provided which can simplify at least one of a tape configuration and a process as compared with the conventional method and can suppress adhesive residue. According to another embodiment of the present invention, a method for manufacturing a semiconductor device including the method for expanding a wafer can be provided.

Drawings

Fig. 1A is a sectional view illustrating the manufacturing method according to embodiment 1.

Fig. 1B is a sectional view illustrating the manufacturing method according to embodiment 1.

Fig. 1C is a sectional view illustrating the manufacturing method according to embodiment 1.

Fig. 2A is a sectional view illustrating the manufacturing method according to embodiment 1.

Fig. 2B is a sectional view illustrating the manufacturing method according to embodiment 1.

Fig. 3 is a sectional view illustrating the manufacturing method according to embodiment 1.

Fig. 4A is a sectional view illustrating the manufacturing method according to embodiment 1.

Fig. 4B is a sectional view illustrating the manufacturing method according to embodiment 1.

Fig. 5A is a sectional view illustrating the manufacturing method according to embodiment 1.

Fig. 5B is a sectional view illustrating the manufacturing method according to embodiment 1.

Fig. 6A is a sectional view illustrating the manufacturing method according to embodiment 2.

Fig. 6B is a sectional view illustrating the manufacturing method according to embodiment 2.

Fig. 6C is a sectional view illustrating the manufacturing method according to embodiment 2.

Fig. 7A is a sectional view illustrating the manufacturing method according to embodiment 2.

Fig. 7B is a sectional view illustrating the manufacturing method according to embodiment 2.

Fig. 7C is a sectional view illustrating the manufacturing method according to embodiment 2.

Fig. 8A is a sectional view illustrating the manufacturing method according to embodiment 3.

Fig. 8B is a sectional view illustrating the manufacturing method according to embodiment 3.

Fig. 8C is a sectional view illustrating the manufacturing method according to embodiment 3.

Fig. 9 is a sectional view illustrating the manufacturing method according to embodiment 3.

Fig. 10 is a plan view illustrating a biaxial stretching device used in the examples.

Fig. 11 is a schematic diagram for explaining a method of measuring chip alignment.

Description of the symbols

10 … No. 1,

100. 100A, 100B … protective layer,

11 … No. 1 base material,

12 … adhesive layer 1,

130. 140 … composite sheet,

20 … No. 2 adhesive sheet,

W … semiconductor wafer (object to be processed),

W1 … circuit surface (No. 1 semiconductor device surface),

W3 … back side (2 nd semiconductor device side).

Detailed Description

[ embodiment 1]

The following describes a film expanding method according to the present embodiment and a method for manufacturing a semiconductor device including the film expanding method.

Fig. 1 (fig. 1A, 1B, and 1C), fig. 2 (fig. 2A and 2B), fig. 3, fig. 4 (fig. 4A and 4B), and fig. 5 (fig. 5A and 5B) are schematic cross-sectional views for explaining a method for manufacturing a semiconductor device including the method for expanding a wafer according to the present embodiment.

The sheet expanding method according to the present embodiment includes at least the following steps (P1) to (P2).

(P1) preparing a plurality of semiconductor devices to be bonded to the 1 st wafer. A plurality of semiconductor devices are bonded to the No. 1 wafer with a protective layer interposed therebetween.

(P2) a step of stretching the 1 st sheet to expand the intervals between the plurality of semiconductor devices.

Fig. 1A, 1B, 1C, 2A, and 2B are diagrams for explaining the step (P1).

(object to be processed)

Fig. 1A is a schematic cross-sectional view of an object having a protective layer.

In the present embodiment, a semiconductor wafer W as an object to be processed is taken as an example for description. In the present invention, the object to be processed is not limited to a wafer.

The semiconductor wafer W has a circuit surface W1 as a1 st object surface and a back surface W3 as a 2 nd object surface. A circuit W2 is formed on the circuit surface W1. In the present embodiment, the protective layer 100 is provided on the circuit surface W1.

The semiconductor wafer W may be, for example, a silicon wafer or a compound semiconductor wafer such as gallium-arsenic. Examples of a method for forming the circuit W2 on the circuit surface W1 of the semiconductor wafer W include a general method, such as an etching method and a Lift-off method (Lift-off method).

(protective layer)

Protective layer 100 is a layer covering circuit surface W1 and 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, more preferably 5 μm or more. The thickness of the protective layer 100 is preferably 500 μm or less, more preferably 300 μm or less.

Examples of the protective layer 100 include: a protective film and a protective sheet.

The protective film is preferably formed by, for example, forming a resin material on the circuit surface W1. The protective film may be formed of one layer or two or more layers. Examples of the film forming method include: printing, spraying, spin coating, and dipping.

Examples of the protective sheet include a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer and a substrate. The base material in the protective sheet is not particularly limited as long as it can function appropriately as one of the members constituting the protective layer and supports the pressure-sensitive adhesive layer. The base material in the protective sheet is preferably formed of a film mainly composed of a resinous material. Examples of the film mainly made of a resin material include: olefinic 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 as long as it can function appropriately as one of the members constituting the protective layer and adheres to the base material and the circuit surface W1. The pressure-sensitive adhesive layer in the protective sheet is preferably formed of at least one pressure-sensitive adhesive selected from the group consisting of acrylic pressure-sensitive adhesives, urethane pressure-sensitive adhesives, polyester pressure-sensitive adhesives, rubber pressure-sensitive adhesives, and silicone pressure-sensitive adhesives, for example, and more preferably formed of an acrylic pressure-sensitive adhesive.

In this embodiment, the case where the protective layer 100 is a protective film formed of one layer is described as an example, but the present invention is not limited to such an embodiment.

[ Back grinding Process ]

The semiconductor wafer W is preferably a wafer obtained by performing a back grinding process. The step (P1) of preparing a plurality of semiconductor devices to be bonded to the 1 st wafer preferably includes the back grinding step as the step (P1-1).

In the back grinding step, 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 grinding the back surface of the semiconductor wafer W. The surface exposed after grinding of the semiconductor wafer W is referred to as a back surface W3.

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 the semiconductor wafer W is ground, an adhesive sheet called a back grinding chip is preferably bonded to the circuit surface W1 in order to protect the circuit W2. In back grinding of the wafer, the circuit surface W1 side, i.e., the back grinding sheet side of the semiconductor wafer W is fixed by a chuck table or the like, and the back side on which no circuit is formed is ground by a grinding machine. The step of bonding the back grinding sheet to the circuit surface W1 is also referred to as a back grinding sheet bonding step.

The thickness of the semiconductor wafer W before grinding is not particularly limited, but is usually 500 μm or more and 1000 μm or less.

The thickness of the semiconductor wafer W after grinding is not particularly limited, but is usually 20 μm or more and 500 μm or less.

[ procedure for applying adhesive sheet 2]

Fig. 1B shows the semiconductor wafer W to which the 2 nd adhesive sheet 20 is bonded to the back surface W3.

The semiconductor wafer W prepared in the step (P1) is preferably a wafer obtained through a back grinding step and further through a bonding step of bonding the 2 nd adhesive sheet 20 to the back surface W3. This bonding step is sometimes referred to as a 2 nd bonding step of the adhesive sheet.

As described later, in the process (P2), the semiconductor wafer W is diced and singulated into a plurality of semiconductor chips CP. When dicing the semiconductor wafer W, an adhesive sheet called a dicing sheet is preferably bonded to the back surface W3 in order to hold the semiconductor wafer W. In the present embodiment, the 2 nd adhesive sheet 20 is preferably a dicing sheet. When the 2 nd psa sheet 20 is used as a dicing sheet, the back surface W3 of the semiconductor wafer W is bonded to the 2 nd psa layer 22 of the 2 nd psa sheet 20. The circuit surface W1 of the semiconductor wafer W corresponds to the circuit surface W1 of the semiconductor chip CP. The rear surface W3 of the semiconductor wafer W corresponds to the rear surface W3 of the semiconductor chip CP.

[ cutting Process ]

Fig. 1C is a diagram illustrating a dicing process for dicing a semiconductor wafer W as an object to be processed. Fig. 1C shows a plurality of semiconductor chips CP held on the 2 nd adhesive sheet 20. In the present embodiment, the semiconductor chip CP is described as an example of the semiconductor device, but the present invention is not limited to such an embodiment. Examples of the semiconductor device include: a chip, a semiconductor device package, and a micro LED.

The plurality of semiconductor devices prepared in the step (P1) are preferably a plurality of semiconductor chips CP obtained by dicing the semiconductor wafer W in a dicing step. The step (P1) preferably includes, as the step (P1-2), a dicing step of dicing the semiconductor wafer W supported by the 2 nd adhesive sheet 20.

The protective layer 100 is provided on the circuit surface W1, and the semiconductor wafer W with the second adhesive sheet 20 bonded to the back surface W3 is diced and singulated to form a plurality of semiconductor chips CP. In this embodiment, the semiconductor wafer W is further cut by cutting the protective layer 100 by cutting the cut from the protective layer 100 side. The circuit surfaces W1 of the plurality of semiconductor chips CP after the dicing step are covered with the protective layer 100 after cutting.

The cutting may be performed by a cutting mechanism such as a microtome (dicing saw).

The cutting depth at the time of cutting is not particularly limited as long as the protective layer 100 and the semiconductor wafer W can be singulated. From the viewpoint of reliably cutting the semiconductor wafer W, the cut in the dicing step is preferably formed to a depth from the protective layer 100 side to the 2 nd psa sheet 20, and more preferably to a depth to the 2 nd psa layer 22 of the 2 nd psa sheet 20. By the dicing, the 2 nd adhesive layer 22 is also cut to the same size as the semiconductor chip CP. In addition, a cut may be formed in the 2 nd base material 21 by dicing.

[ bonding Process of the first sheet ]

Fig. 2A is a diagram for explaining a process of bonding the 1 st sheet 10 to the plurality of semiconductor chips CP after the dicing process. Fig. 2A shows a state in which the 1 st sheet 10 is attached to the plurality of semiconductor chips CP obtained by the dicing process. The 1 st sheet 10 of the present embodiment is a pressure-sensitive adhesive sheet having a1 st pressure-sensitive adhesive layer 12 and a1 st substrate 11. Details of the 1 st sheet 10 are described later. In the present invention, the 1 st sheet is not limited to the pressure-sensitive adhesive sheet having the two-layer structure of the 1 st pressure-sensitive adhesive layer and the 1 st substrate.

In the present embodiment, when the 1 st sheet 10 is bonded to the circuit surface W1 side of the plurality of semiconductor chips CP, a laminated structure in which the singulated protective layer 100 is interposed between the plurality of semiconductor chips CP and the 1 st adhesive layer 12 of the 1 st sheet 10 can be obtained.

[ peeling Process of adhesive sheet 2]

Fig. 2B is a view for explaining a step of peeling off the 2 nd adhesive sheet 20 after the 1 st sheet bonding step. This step is sometimes referred to as a step of peeling off the 2 nd adhesive sheet. Fig. 2B shows a state in which the 2 nd adhesive sheet 20 is peeled from the back surface W3 of the semiconductor wafer W after the 1 st sheet 10 is bonded.

When the 2 nd adhesive sheet 20 is peeled off after the 1 st sheet 10 is bonded, the back surfaces W3 of the plurality of semiconductor chips CP are exposed.

When the energy ray polymerizable compound is blended in the 2 nd pressure-sensitive adhesive layer 22, it is preferable that the 2 nd pressure-sensitive adhesive sheet 20 is peeled after the energy ray polymerizable compound is cured by irradiating the energy ray from the 2 nd substrate 21 side to the 2 nd pressure-sensitive adhesive layer 22.

[ sheet expansion Process ]

Fig. 3 is a diagram for explaining the step (P2). The step (P2) may be referred to as a sheet expanding step. Fig. 3 shows a state where the 1 st sheet 10 is stretched to enlarge the intervals of the plurality of semiconductor chips CP after the 2 nd adhesive sheet 20 is peeled off.

When the interval between the plurality of semiconductor chips CP is widened, it is preferable to stretch the expansion sheet while holding the plurality of semiconductor chips CP with an adhesive sheet called an expansion sheet. In the present embodiment, the 1 st sheet 10 is preferably an expanded sheet.

The method of stretching the 1 st sheet 10 in the sheet expanding step is not particularly limited. The method of stretching the 1 st sheet 10 includes, for example: a method of stretching the 1 st sheet 10 by being placed on a ring-shaped or circular expander, a method of stretching the 1 st sheet 10 by grasping the outer periphery of the 1 st sheet with a grasping member or the like, and the like. In the present embodiment, the interval D1 between the plurality of semiconductor chips CP depends on the size of the semiconductor chip CP, and is not particularly limited. In particular, the distance D1 between adjacent semiconductor chips CP among the plurality of semiconductor chips CP attached to one surface 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 mutual spacing of the semiconductor chips CP may be, for example, 6000 μm.

[ first transfer step ]

In the present embodiment, a step of transferring the plurality of semiconductor chips CP attached to the 1 st adhesive sheet 10 to another adhesive sheet (for example, the 5 th adhesive sheet) (hereinafter, may be referred to as "the 1 st transfer step") may be performed after the expanding step.

Fig. 4A is a diagram illustrating a step of transferring the plurality of semiconductor chips CP attached to the 1 st adhesive sheet 10 to the 5 th adhesive sheet 50 (hereinafter, may be referred to as a "transfer step").

The 5 th adhesive sheet 50 is not particularly limited as long as it can hold a plurality of semiconductor chips CP. The 5 th adhesive sheet 50 has a 5 th substrate 51 and a 5 th adhesive layer 52.

In the case where the transfer step is performed in the present embodiment, it is preferable that, for example, after the expanding step, the 5 th adhesive sheet 50 is bonded to the back surfaces W3 of the plurality of semiconductor chips CP, and then the 1 st sheet 10 is peeled off.

The 5 th adhesive sheet 50 may be attached to the second ring frame along with the plurality of semiconductor chips CP. In this case, the ring frame is placed on the 5 th adhesive layer 52 of the 5 th adhesive sheet 50 and fixed by lightly pressing the ring frame. Then, the 5 th adhesive layer 52 exposed inside the ring shape of the ring frame is pressure-bonded to the back surface W3 of the semiconductor chip CP, and the plurality of semiconductor chips CP are fixed to the 5 th adhesive sheet 50.

Fig. 4B is a diagram illustrating a step of peeling the 1 st sheet 10 after the 5 th adhesive sheet 50 is bonded.

In the present embodiment, a description has been given of an example in which the first singulated sheet 10 covering the circuit surface W1 of the semiconductor chip CP is peeled off together with the protective layer 100 when the first sheet 10 is peeled off. Note that, the protection layer 100 after singulation, which covers the circuit surface W1, may be left on the semiconductor chip CP to peel off only the 1 st sheet 10.

When the 1 st sheet 10 and the protective layer 100 are peeled off after the 5 th adhesive sheet 50 is bonded, the circuit surface W1 of the plurality of semiconductor chips CP is exposed. After the first sheet 10 and the protective layer 100 are peeled off, the distance D1 between the plurality of expanded semiconductor chips CP is preferably maintained in the expanding step.

[ 2 nd transfer Process ]

Fig. 5A is a diagram illustrating a step of transferring the plurality of semiconductor chips CP attached to the 5 th adhesive sheet 50 to the 6 th adhesive sheet 60 (hereinafter, may be referred to as a "2 nd transfer step").

The plurality of semiconductor chips CP transferred from the 5 th adhesive sheet 50 to the 6 th adhesive sheet 60 preferably maintain the interval D1 between the semiconductor chips CP.

The 6 th adhesive sheet 60 is not particularly limited as long as it can hold a plurality of semiconductor chips CP. The 6 th adhesive sheet 60 has a 6 th substrate 61 and a 6 th adhesive layer 62.

When it is desired to seal the plurality of semiconductor chips CP on the 6 th adhesive sheet 60, an adhesive sheet for a sealing process is preferably used as the 6 th adhesive sheet 60, and an adhesive sheet having heat resistance is more preferably used. In the case of using a heat-resistant adhesive sheet as the 6 th adhesive sheet 60, the 6 th substrate 61 and the 6 th adhesive layer 62 are preferably formed of a material having heat resistance capable of withstanding the temperature applied in the sealing step.

The semiconductor chips CP transferred from the 5 th adhesive sheet 50 to the 6 th adhesive sheet 60 are bonded to the 6 th adhesive layer 62 with the circuit surface W1 facing thereto.

[ sealing Process ]

Fig. 5B is a diagram illustrating a process of sealing the plurality of semiconductor chips CP with the sealing member 300 (hereinafter, may be referred to as a "sealing process").

In the present embodiment, the sealing process is performed after the plurality of semiconductor chips CP are transferred to the 6 th adhesive sheet 60.

In the sealing step, the sealing member 300 covers the plurality of semiconductor chips CP with the circuit surface W1 protected by the 6 th adhesive sheet 60, thereby forming the sealing body 3. The sealing member 300 is also filled between the plurality of semiconductor chips CP. Since the circuit surface W1 and the circuit W2 are covered by the 6 th adhesive sheet 60, the circuit surface W1 can be prevented from being covered by the sealing member 300.

By the sealing process, the sealing body 3 in which the plurality of semiconductor chips CP separated by a predetermined distance are embedded in the sealing member 300 can be obtained. In the sealing step, the plurality of semiconductor chips CP are preferably covered with the sealing member 300 while maintaining the interval D1 after the expanding step.

After the sealing process, the 6 th adhesive sheet 60 is peeled off. When the 6 th adhesive sheet 60 is peeled off, the circuit surface W1 of the semiconductor chip CP and the surface 3A of the sealing body 3 which has contacted the 6 th adhesive sheet 60 are exposed.

After the above-described expanding step, the transfer step and the expanding step are repeated an arbitrary number of times, whereby the distance between the semiconductor chips CP can be made a desired distance, and the orientation of the circuit surface when the semiconductor chips CP are sealed can be made a desired orientation.

[ other Processes ]

After the adhesive sheet is peeled off from the sealing body 3, a rewiring layer forming step of forming a rewiring layer electrically connected to the semiconductor chip CP and a connecting step of electrically connecting the rewiring layer to the external terminal electrode are sequentially performed with respect to the sealing body 3. The electrical circuit of the semiconductor chip CP can be electrically connected to the external terminal electrode by the rewiring layer forming step and the connection step to the external terminal electrode.

The sealing body 3 to which the external terminal electrodes are connected is singulated into units of semiconductor chips CP. The method for singulating the sealing body 3 is not particularly limited. By singulating the sealing body 3, a semiconductor package of the semiconductor chip CP unit can be manufactured. The semiconductor package to which the external electrodes outside the area of the fan-out to the semiconductor chip CP are connected is manufactured as a fan-out wafer level package (FO-WLP).

(the 1 st sheet)

The 1 st sheet 10 of the present embodiment has a1 st substrate 11 and a1 st adhesive layer 12. The 1 st adhesive layer 12 is laminated on the 1 st substrate 11.

1 st base Material

The material of the 1 st base material 11 is not particularly limited as long as it can function properly in a desired step (e.g., the step (P2)) such as a sheet expanding step.

The 1 st substrate 11 has a1 st substrate surface and a1 st substrate back surface. The 1 st base material back surface is a surface opposite to the 1 st base material front surface.

In the 1 st sheet 10, the 1 st adhesive layer 12 is preferably provided on one of the 1 st substrate front surface and the 1 st substrate back surface, and the other surface is preferably not provided with an adhesive layer.

From the viewpoint of easy large stretching, the material of the 1 st base material 11 is preferably a thermoplastic elastomer or a rubber-like material, and more preferably a thermoplastic elastomer.

In addition, as the material of the 1 st substrate 11, a resin having a low glass transition temperature (Tg) is preferably used from the viewpoint of easy large stretching. The glass transition temperature (Tg) of such a resin is preferably 90 ℃ or lower, more preferably 80 ℃ or lower, and further preferably 70 ℃ or lower.

As the thermoplastic elastomer, there can be mentioned: urethane elastomers, olefin elastomers, vinyl chloride elastomers, polyester elastomers, styrene elastomers, acrylic elastomers, amide elastomers, and the like. The thermoplastic elastomer may be used alone or in combination of two or more. As the thermoplastic elastomer, a urethane elastomer is preferably used from the viewpoint of easy large stretching.

The urethane elastomer is generally obtained by reacting a long-chain polyol, a chain extender and a diisocyanate. The urethane elastomer includes a soft segment having a structural unit derived from a long-chain polyol, and a hard segment having a polyurethane structure obtained by reacting a chain extender with a diisocyanate.

If the urethane elastomer is classified according to the type of the long-chain polyol, the urethane elastomer can be classified into a polyester-based polyurethane elastomer, a polyether-based polyurethane elastomer, a polycarbonate-based polyurethane elastomer, and the like. The urethane elastomer may be used alone or in combination of two or more. In the present embodiment, the urethane elastomer is preferably a polyether urethane elastomer from the viewpoint of easy large stretching.

Examples of long-chain polyols include: polyester polyols such as lactone polyester polyols and adipate polyester polyols; polyether polyols such as polypropylene (ethylene) polyol and polytetramethylene ether glycol; polycarbonate polyols, and the like. In the present embodiment, the long-chain polyol is preferably an adipate polyester polyol from the viewpoint of easy large stretching.

Examples of diisocyanates include: 2, 4-tolylene diisocyanate, 2, 6-tolylene diisocyanate, 4' -diphenylmethane diisocyanate, hexamethylene diisocyanate, and the like. In the present embodiment, the diisocyanate is preferably hexamethylene diisocyanate in view of easy large stretching.

As the chain extender, there may be mentioned: low molecular weight polyols (e.g., 1, 4-butanediol, and 1, 6-hexanediol), and aromatic diamines. Among them, 1, 6-hexanediol is preferably used from the viewpoint of easy large stretching.

Examples of the olefin-based elastomer include elastomers containing at least one resin selected from the group consisting of an ethylene/α -olefin copolymer, a propylene/α -olefin copolymer, a butene/α -olefin copolymer, an ethylene/propylene/α -olefin copolymer, an ethylene/butene/α -olefin copolymer, a propylene/butene/α -olefin copolymer, an ethylene/propylene/butene/α -olefin copolymer, a styrene/isoprene copolymer, and a styrene/ethylene/butene copolymer. The olefinic elastomer may be used singly or in combination of two or more.

The density of the olefinic elastomer is not particularly limited. For example, the density of the olefinic elastomer is preferably 0.860g/cm³Above and less than 0.905g/cm³More preferably 0.862g/cm³Above and less than 0.900g/cm³Particularly preferably 0.864g/cm³Above and below 0.895g/cm³. When the density of the olefin elastomer satisfies the above range, the substrate is excellent in the unevenness follow-up property and the like when a semiconductor device as an adherend is attached to the adhesive sheet.

The olefin-based elastomer is preferably such that the mass ratio of the monomers including the olefin-based compound (also referred to as "olefin content" in the present specification) is 50 mass% or more and 100 mass% or less of the total monomers used to form the elastomer.

When the olefin content is too low, the properties of the elastomer including the olefin-derived structural unit are not easily exhibited, and the flexibility and rubber elasticity of the base material are not easily exhibited.

The olefin content is preferably 50 mass% or more, more preferably 60 mass% or more, from the viewpoint of stably obtaining flexibility and rubber elasticity.

Examples of the styrene-based elastomer include: styrene-conjugated diene copolymers, styrene-olefin copolymers, and the like. Specific examples of the styrene-conjugated diene copolymer include: hydrogenated styrene-conjugated diene copolymers such as styrene-butadiene copolymers, styrene-butadiene-styrene copolymers (SBS), styrene-butadiene-butylene-styrene copolymers, styrene-isoprene-styrene copolymers (SIS), and unhydrogenated styrene-conjugated diene copolymers such as styrene-ethylene-isoprene-styrene copolymers, styrene-ethylene/propylene-styrene copolymers (SEPS, hydrogenated products of styrene-isoprene-styrene copolymers), and styrene-ethylene-butylene-styrene copolymers (SEBS, hydrogenated products of styrene-butadiene copolymers). Further, industrially, as the styrene-based elastomer, there can be mentioned: trade names such as Tufprene (manufactured by Asahi Kasei corporation), Kraton (manufactured by Kraton Polymers Japan), Sumitomo TPE-SB (manufactured by Sumitomo chemical Co., Ltd.), EPFRIEND (manufactured by Dacellosolve Co., Ltd.), Rubberron (manufactured by Mitsubishi chemical Co., Ltd.), Septon (manufactured by Cola Co., Ltd.), and Tuftec (manufactured by Asahi Kasei corporation). The styrenic elastomer may be a hydrogenated product or may be an unhydrogenated product.

Examples of the rubber-like material include: natural rubber, synthetic Isoprene Rubber (IR), Butadiene Rubber (BR), styrene-butadiene rubber (SBR), Chloroprene Rubber (CR), nitrile-butadiene rubber (NBR), butyl rubber (IIR), halobutyl rubber, acrylic rubber, urethane rubber, polysulfide rubber, and the like. The rubber-like material may be used alone or in combination of two or more of these.

The 1 st substrate 11 may be a laminated film obtained by laminating a plurality of films made of the above-described material (for example, a thermoplastic elastomer or a rubber-based material). The 1 st substrate 11 may be a laminated film obtained by laminating a film made of the above-described material (for example, a thermoplastic elastomer or a rubber-based material) and another film.

The 1 st substrate 11 may contain an additive in the film containing the above-mentioned resinous material as a main material. Specific examples of the additives are the same as those listed in the description of the 1 st base material 11. Examples of additives include: pigments, dyes, flame retardants, plasticizers, antistatic agents, lubricants, fillers, and the like. Examples of pigments include: titanium dioxide, carbon black, and the like. Examples of the filler include organic materials such as melamine resin, inorganic materials such as fumed silica, and metal materials such as nickel particles. The content of the additive optionally contained in the film is not particularly limited, and preferably falls within a range enabling the 1 st substrate 11 to exert a desired function.

The 1 st base material 11 may be treated such that one or both surfaces of the 1 st base material 11 are treated to improve adhesion to the 1 st pressure-sensitive adhesive layer 12 laminated on the surface of the 1 st base material 11.

When the 1 st adhesive layer 12 contains an energy ray-curable adhesive, the 1 st substrate 11 preferably has transparency to an energy ray. When ultraviolet rays are used as the energy rays, the 1 st base material 11 preferably has transparency to ultraviolet rays. In the case of using an electron beam as the energy ray, the 1 st base material 11 preferably has electron beam transmissivity.

The thickness of the 1 st base material 11 is not limited as long as the 1 st sheet 10 can function properly in a desired process. The thickness of the 1 st substrate 11 is preferably 20 μm or more, more preferably 40 μm or more. The thickness of the 1 st base material 11 is preferably 250 μm or less, and more preferably 200 μm or less.

When the thickness of the 1 st base material 11 is measured at a plurality of locations at 2cm intervals in the in-plane direction on the 1 st base material front surface or the 1 st base material back surface, the standard deviation of the thickness of the 1 st base material 11 is preferably 2 μm or less, more preferably 1.5 μm or less, and still more preferably 1 μm or less. By setting the standard deviation to 2 μm or less, the 1 st sheet 10 has a highly accurate thickness, and the 1 st sheet 10 can be uniformly stretched.

The tensile elastic modulus of the 1 st base material 11 in the MD direction and the CD direction is 10MPa or more and 350MPa or less, respectively, at 23 ℃, and the 100% stress of the 1 st base material 11 in the MD direction and the CD direction is 3MPa or more and 20MPa or less, respectively, at 23 ℃.

By setting the tensile elastic modulus and the 100% stress in the above ranges, the 1 st sheet 10 can be largely stretched.

The 100% stress of the 1 st base material 11 is a value obtained in the following manner. A test piece having a size of 150mm (longitudinal direction). times.15 mm (width direction) was cut out from the No. 1 base material 11. The both ends in the longitudinal direction of the cut test piece were clamped with clamps so that the length between the clamps was 100 mm. After the test piece was clamped by the clamps, the test piece was stretched at a speed of 200 mm/min in the longitudinal direction, and the measurement value of the stretching force was read when the length between the clamps reached 200 mm. The 100% stress of the 1 st base material 11 is a value obtained by dividing the measured value of the tensile force read by the cross-sectional area of the base material. The cross-sectional area of the 1 st base 11 was calculated by the length in the width direction of 15mm × the thickness of the 1 st base 11 (test piece). The cutting was performed so that the running direction (MD direction) or the direction perpendicular to the MD direction (CD direction) of the base material during the production was aligned with the longitudinal direction of the test piece. In the 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.

The elongation at break of the 1 st base material 11 in the MD direction and the CD direction is preferably 100% or more, respectively, at 23 ℃.

By setting the elongation at break of the 1 st base material 11 in the MD direction and the CD direction to 100% or more, the 1 st sheet 10 can be greatly stretched without breaking.

The tensile modulus (MPa) of the substrate and the elongation (%) at break of the substrate can be measured as follows. The substrate was cut into pieces of 15mm by 140mm to obtain test pieces. The test piece was measured for elongation at break and tensile modulus at 23 ℃ in accordance with JIS K7161:2014 and JIS K7127: 1999. Specifically, the test piece was subjected to a tensile test at a speed of 200 mm/min with a distance between chucks set to 100mm using a tensile tester (product name "Autograph AG-IS 500N" manufactured by Shimadzu corporation), and the elongation at break (%) and the tensile modulus (MPa) were measured. The measurement is performed in both the direction of travel (MD) and the direction perpendicular thereto (CD) during the production of the base material.

1 st adhesive layer

The material of the 1 st pressure-sensitive adhesive layer 12 is not particularly limited as long as it can function properly in a desired step such as a sheet expanding step. Examples of the binder contained in the 1 st adhesive layer 12 include: rubber-based adhesives, acrylic adhesives, silicone-based adhesives, polyester-based adhesives, and urethane-based adhesives.

Energy ray-curable resin (ax1)

The 1 st adhesive layer 12 preferably contains an energy ray-curable resin (ax 1). The energy ray-curable resin (ax1) has an energy ray-curable double bond in the molecule.

The adhesive layer containing an energy ray-curable resin is cured by irradiation with an energy ray, and the adhesive force is reduced. In the case where the adherend is to be separated from the adhesive sheet, the adherend can be easily separated by irradiating the adhesive layer with an energy ray.

The energy ray-curable resin (ax1) is preferably a (meth) acrylic resin.

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

The energy ray-curable resin (ax1) is a resin which is cured by polymerization when irradiated with an energy ray. Examples of the energy ray include ultraviolet rays and electron beams.

Examples of the energy ray-curable resin (ax1) include low molecular weight compounds (monofunctional monomers, polyfunctional monomers, monofunctional oligomers, and polyfunctional oligomers) having an energy ray-polymerizable group. Specifically, as the energy ray-curable resin (a1), an acrylate such as trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, pentaerythritol triacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, 1, 4-butanediol diacrylate, and 1, 6-hexanediol diacrylate, an acrylate having a cyclic aliphatic skeleton such as dicyclopentadiene dimethoxy diacrylate and isobornyl acrylate, and an acrylate compound such as polyethylene glycol diacrylate, oligoester acrylate, urethane acrylate oligomer, epoxy-modified acrylate, polyether acrylate, and itaconic acid oligomer can be used. The energy ray-curable resin (a1) may be used singly or in combination of two or more.

The molecular weight of the energy ray-curable resin (ax1) is usually 100 or more and 30000 or less, and preferably 300 or more and 10000 or less.

(meth) acrylic copolymer (b1)

The 1 st adhesive layer 12 preferably further contains a (meth) acrylic copolymer (b 1). The (meth) acrylic copolymer is different from the energy ray-curable resin (ax 1).

The (meth) acrylic copolymer (b1) preferably has an energy ray-curable carbon-carbon double bond. That is, in the present embodiment, the 1 st adhesive layer 12 preferably contains the energy ray-curable resin (ax1) and the energy ray-curable (meth) acrylic copolymer (b 1).

In the 1 st pressure-sensitive adhesive layer 12, the energy ray-curable resin (ax1) is contained in a proportion of preferably 10 parts by weight or more, more preferably 20 parts by weight or more, and still more preferably 25 parts by weight or more, based on 100 parts by weight of the (meth) acrylic copolymer (b 1).

In the 1 st pressure-sensitive adhesive layer 12, the energy ray-curable resin (ax1) is contained preferably in a proportion of 80 parts by weight or less, more preferably 70 parts by weight or less, and still more preferably 60 parts by weight or less, based on 100 parts by weight of the (meth) acrylic copolymer (b 1).

The weight average molecular weight (Mw) of the (meth) acrylic copolymer (b1) is preferably 1 ten thousand or more, more preferably 15 ten thousand or more, and further preferably 20 ten thousand or more.

The weight average molecular weight (Mw) of the (meth) acrylic copolymer (b1) is preferably 150 ten thousand or less, and more preferably 100 ten thousand or less.

The weight average molecular weight (Mw) in the present specification is a value measured by gel permeation chromatography (GPC method) in terms of standard polystyrene.

The (meth) acrylic copolymer (b1) is preferably a (meth) acrylate polymer (b2) (hereinafter, sometimes referred to as "energy ray-curable polymer (b 2)") having an energy ray-curable functional group (energy ray-curable group) introduced into a side chain thereof.

Energy ray-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.

In the present specification, the term (meth) acrylate refers to both acrylate and methacrylate. Other similar terms are also the same.

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

The functional group-containing monomer as a constituent unit of the acrylic copolymer (b21) is preferably a monomer having a polymerizable double bond and a functional group in the molecule. The functional group is preferably at least one functional group selected from a hydroxyl group, a carboxyl group, an amino group, a substituted amino group, an epoxy group, and the like.

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 singly or in combination of two or more.

Examples of the carboxyl group-containing monomer include: ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. The carboxyl group-containing monomers may be used singly or in combination of two or more.

Examples of the amino group-containing monomer or the substituted amino group-containing monomer include: aminoethyl (meth) acrylate, n-butylaminoethyl (meth) acrylate, and the like. The amino group-containing monomer or the substituted amino group-containing monomer may be used singly or in combination of two or more.

As the (meth) acrylate monomer constituting the acrylic copolymer (b21), for example, a monomer having an alicyclic structure in the molecule (alicyclic structure-containing monomer) may be preferably used in addition to the alkyl (meth) acrylate in which the alkyl group has 1 to 20 carbon atoms.

The alkyl (meth) acrylate is preferably an alkyl (meth) acrylate in which the alkyl group has 1 to 18 carbon atoms. The alkyl (meth) acrylate is more preferably, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, or the like. The alkyl (meth) acrylate may be used singly or in combination of two or more.

As the alicyclic structure-containing monomer, for example, cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, adamantyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, and dicyclopentenyloxyethyl (meth) acrylate can be preferably used. The alicyclic structure-containing monomer may be used singly or in combination of two or more.

The acrylic copolymer (b21) preferably contains the structural unit derived from the functional group-containing monomer at a ratio of 1% by mass or more, more preferably contains the structural unit derived from the functional group-containing monomer at a ratio of 5% by mass or more, and still more preferably contains the structural unit derived from the functional group-containing monomer at a ratio of 10% by mass or more.

The acrylic copolymer (b21) preferably contains the structural unit derived from the functional group-containing monomer at a ratio of 35% by mass or less, more preferably at a ratio of 30% by mass or less, and still more preferably at a ratio of 25% by mass or less.

Further, the acrylic copolymer (b21) preferably contains a structural unit derived from a (meth) acrylate monomer or a derivative thereof at a ratio of 50% by mass or more, more preferably contains a structural unit derived from a (meth) acrylate monomer or a derivative thereof at a ratio of 60% by mass or more, and still more preferably contains a structural unit derived from a (meth) acrylate monomer or a derivative thereof at a ratio of 70% by mass or more.

The acrylic copolymer (b21) preferably contains a structural unit derived from a (meth) acrylate monomer or a derivative thereof in an amount of 99% by mass or less, more preferably contains a structural unit derived from a (meth) acrylate monomer or a derivative thereof in an amount of 95% by mass or less, and still more preferably contains a structural unit derived from a (meth) acrylate monomer or a derivative thereof in an amount of 90% by mass or less.

The acrylic copolymer (b21) can be obtained by copolymerizing the above-mentioned functional group-containing monomer with a (meth) acrylate monomer or a derivative thereof by a usual method.

The acrylic copolymer (b21) may contain, in addition to the above-mentioned monomers, at least one structural unit selected from the group consisting of dimethylacrylamide, vinyl formate, vinyl acetate, styrene, and the like.

The energy ray-curable polymer (b2) can be obtained by reacting the acrylic copolymer (b21) having the functional group-containing monomer unit with the unsaturated group-containing compound (b22) having a functional group bonded to the functional group thereof.

The functional group of the unsaturated group-containing compound (b22) can be appropriately selected depending on the kind of the functional group-containing monomer unit of the acrylic copolymer (b 21). 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 carboxyl group, or an aziridine group.

The unsaturated group-containing compound (b22) contains at least 1 energy ray-polymerizable carbon-carbon double bond in 1 molecule, preferably 1 or more and 6 or less, and more preferably 1 or more and 4 or less energy ray-polymerizable carbon-carbon double bonds.

Examples of the unsaturated group-containing compound (b22) include: 2-methacryloyloxyethyl isocyanate (2-isocyanatoethyl methacrylate),M-isopropenyl-alpha, alpha-dimethylbenzyl isocyanate, methacryloyl isocyanate, allyl isocyanate, 1- (bisacryloxymethyl) ethyl isocyanate; an acryloyl monoisocyanate compound obtained by the reaction of a diisocyanate compound or a polyisocyanate compound with hydroxyethyl (meth) acrylate; an acryloyl group monoisocyanate compound obtained by the reaction of a diisocyanate compound or a polyisocyanate compound, 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.

The unsaturated group-containing compound (b22) is used preferably at a ratio of 50 mol% or more (addition rate), more preferably at a ratio of 60 mol% or more, and still more preferably at a ratio of 70 mol% or more, based on the number of moles of the functional group-containing monomer in the acrylic copolymer (b 21).

The unsaturated group-containing compound (b22) is used preferably at a ratio of 95 mol% or less, more preferably at a ratio of 93 mol% or less, and still more preferably at a ratio of 90 mol% or less, based on the number of moles of the functional group-containing monomer in the acrylic copolymer (b 21).

In the reaction of the acrylic copolymer (b21) and the unsaturated group-containing compound (b22), the temperature, pressure, solvent, time, presence or absence of a catalyst, and the kind of a catalyst for the reaction can be appropriately selected depending on the combination of the functional group of the acrylic copolymer (b21) and the functional group of the unsaturated group-containing compound (b 22). As a result, the functional group of the acrylic copolymer (b21) and the functional group of the unsaturated group-containing compound (b22) were reacted with each other, and an unsaturated group was introduced into the side chain of the acrylic copolymer (b21), thereby obtaining an energy ray-curable polymer (b 2).

The weight average molecular weight (Mw) of the energy ray-curable polymer (b2) is preferably 1 ten thousand or more, more preferably 15 ten thousand or more, and further preferably 20 ten thousand or more.

The weight average molecular weight (Mw) of the energy ray-curable polymer (b2) is preferably 150 ten thousand or less, and more preferably 100 ten thousand or less.

Photopolymerization initiator (C)

When the 1 st adhesive layer 12 contains an ultraviolet-curable compound (for example, an ultraviolet-curable resin), the 1 st adhesive layer 12 preferably contains a photopolymerization initiator (C).

By containing the photopolymerization initiator (C) in the 1 st pressure-sensitive adhesive layer 12, the polymerization curing time and the light irradiation amount can be reduced.

Specific examples of the photopolymerization initiator (C) include: benzoin compounds, acetophenone compounds, acylphosphine oxide 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-phenylpropan-1-one, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl phenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, bibenzyl, butanedione, 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.

The amount of the photopolymerization initiator (C) is preferably 0.01 to 10 parts by weight, more preferably 0.03 to 5 parts by weight, and still more preferably 0.05 to 5 parts by weight, based on 100 parts by weight of the adhesive resin.

When the energy ray-curable resin (ax1) and the (meth) acrylic copolymer (b1) are blended in the adhesive layer, the photopolymerization initiator (C) is preferably used in an amount of 0.1 part by mass or more, more preferably in an amount of 0.5 part by mass or more, based on 100 parts by mass of the total amount of the energy ray-curable resin (ax1) and the (meth) acrylic copolymer (b 1).

When the energy ray-curable resin (ax1) and the (meth) acrylic copolymer (b1) are blended in the adhesive layer, the photopolymerization initiator (C) is preferably used in an amount of 10 parts by mass or less, more preferably 6 parts by mass or less, based on 100 parts by mass of the total amount of the energy ray-curable resin (ax1) and the (meth) acrylic copolymer (b 1).

The 1 st pressure-sensitive adhesive layer 12 may contain other components in addition to the above components as appropriate. Examples of the other component include a crosslinking agent (E).

Crosslinking agent (E)

As the crosslinking agent (E), a polyfunctional compound having reactivity with a functional group carried by the (meth) acrylic copolymer (b1) or the like can be used. Examples of the polyfunctional compound in the 1 st sheet 10 include: isocyanate compound, epoxy compound, amine compound, melamine compound, aziridine compound, hydrazine compound, aldehyde compound, and the like,

Oxazoline compounds, metal alkoxide compounds, metal chelate compounds, metal salts, ammonium salts, and reactive phenol resins.

The blending 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 further preferably 0.04 part by mass or more, relative to 100 parts by mass of the (meth) acrylic copolymer (b 1).

The amount of the crosslinking agent (E) blended is preferably 8 parts by mass or less, more preferably 5 parts by mass or less, and still more preferably 3.5 parts by mass or less, per 100 parts by mass of the (meth) acrylic copolymer (b 1).

The thickness of the 1 st adhesive layer 12 is not particularly limited. The thickness of the 1 st adhesive layer 12 is, for example, preferably 10 μm or more, and more preferably 20 μm or more. The thickness of the 1 st pressure-sensitive adhesive layer 12 is preferably 150 μm or less, and more preferably 100 μm or less.

The recovery rate of the 1 st sheet 10 is preferably 70% or more, more preferably 80% or more, and further preferably 85% or more. The recovery rate of the 1 st sheet 10 is preferably 100% or less. By setting the recovery rate in the above range, the adhesive sheet can be greatly stretched.

The recovery rate is obtained by: when a test piece obtained by cutting a pressure-sensitive adhesive sheet into 150mm (length direction) × 15mm (width direction) was cut, both ends in the length direction were clamped by clamps so that the length between the clamps became 100mm, then the test piece was stretched at a speed of 200 mm/min until the length between the clamps became 200mm, the test piece was held for 1 minute in a state where the length between the clamps was expanded to 200mm, then the test piece was restored at a speed of 200 mm/min until the length between the clamps became 100mm, the test piece was held for 1 minute in a state where the length between the clamps was restored to 100mm, then the test piece was stretched at a speed of 60 mm/min in the length direction, the measured value of the stretching force showed a length between the clamps at 0.1N/15mm, the length obtained by subtracting the initial length between the clamps from the measured value was L2(mm), and the length obtained by subtracting the initial length between the clamps from the length between the clamps at 200mm in the expanded state was L1(mm), the calculation is performed by the following formula (mathematical formula 2).

Recovery rate (%) { 1- (L2 ÷ L1) } × 100 · (equation 2)

When the recovery rate is within the above range, it means that the pressure-sensitive adhesive sheet is easily recovered even after being largely stretched. Generally, when a sheet having a yield point is stretched to a value equal to or higher than the yield point, the sheet is plastically deformed, and a portion subjected to plastic deformation, that is, a portion subjected to extreme stretching, is in a state in which unevenness exists. When the sheet in such a state is further stretched, the sheet may be broken from the portion subjected to the extreme stretching or may be unevenly expanded even if the sheet is not broken. In addition, in the stress-strain graph obtained by plotting the strain on the x-axis and the elongation on the y-axis, even in the case of a sheet which does not exhibit a clear yield point and whose slope dx/dy does not have a stress value changing from a positive value to 0 or a negative value, the sheet is plastically deformed as the tensile amount becomes larger, and similarly, breakage is caused or the sheet expansion becomes nonuniform. On the other hand, when elastic deformation occurs, rather than plastic deformation, the sheet is easily restored to its original shape by relieving the stress. Therefore, by setting the recovery ratio, which is an index indicating how much the psa sheet recovers after 100% elongation, to the above range, the plastic deformation of the film when the psa sheet is stretched to a large extent can be minimized, and uniform sheet expansion with less breakage can be achieved.

(Release sheet)

A release sheet is adhered to the surface of the 1 st sheet 10. Specifically, the release sheet is attached to the surface of the 1 st adhesive layer 12 of the 1 st sheet 10. The release sheet is attached to the surface of the 1 st pressure-sensitive adhesive layer 12, thereby protecting the 1 st pressure-sensitive adhesive layer 12 during transportation and storage. The release sheet is releasably adhered to the 1 st sheet 10 and is peeled and removed from the 1 st sheet 10 before the 1 st sheet 10 is used.

The release sheet may be one having at least one surface subjected to a release treatment. Specific examples thereof include: a release sheet is provided with a substrate for release sheet and a release agent layer formed by applying a release agent on the surface of the substrate.

The substrate for a release sheet is preferably a resin film. Examples of the resin constituting the resin film as the base material for the release sheet include: and polyester resin films such as polyethylene terephthalate resins, polybutylene terephthalate resins, and polyethylene naphthalate resins, and polyolefin resins such as polypropylene resins and polyethylene resins.

Examples of the release agent include: rubber elastomers such as silicone resins, olefin resins, isoprene resins, butadiene resins, long-chain alkyl resins, alkyd resins, and fluorine resins.

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

(method for producing adhesive sheet)

The method for producing the adhesive sheet described in the 1 st sheet 10 and the other descriptions herein is not particularly limited, and the adhesive sheet can be produced by a known method.

For example, an adhesive sheet having a release sheet attached to the surface of an adhesive layer can be produced by bonding the adhesive layer provided on the release sheet to one surface of a substrate. Further, a laminate of the cushion layer and the base material can be obtained by bonding the cushion layer provided on the release sheet to the base material and removing the release sheet. Then, the pressure-sensitive adhesive layer provided on the release sheet is bonded to the base material side of the laminate, whereby a pressure-sensitive adhesive sheet having the release sheet bonded to the surface of the pressure-sensitive adhesive layer can be produced. When the cushion layer is provided on both surfaces of the base material, the adhesive layer is formed on the cushion layer. The release sheet attached to the surface of the pressure-sensitive adhesive layer may be removed by appropriately peeling before the pressure-sensitive adhesive sheet is used.

As a more specific example of the method for producing the adhesive sheet, the following method can be mentioned. First, a coating liquid containing an adhesive composition constituting the adhesive layer and, if necessary, a further added solvent or dispersion medium is prepared. Next, the coating liquid is applied to one surface of the substrate by the application mechanism to form a coating film. Examples of the coating mechanism include: die coaters, curtain coaters, spray coaters, slit coaters, blade coaters, and the like. Subsequently, the coating film is dried to form a pressure-sensitive adhesive layer. The coating liquid is not particularly limited in its properties as long as it can be applied. The coating liquid includes both a case of containing a component for forming the adhesive layer as a solute and a case of containing a component for forming the adhesive layer as a dispersoid. Similarly, the adhesive composition may be directly applied to one surface of the substrate or the cushion layer to form an adhesive layer.

As another more specific example of the method for producing the pressure-sensitive adhesive sheet, the following method can be mentioned. First, a coating liquid is applied to the release surface of the release sheet to form a coating film. Next, the coating film is dried to form a laminate composed of the pressure-sensitive adhesive layer and the release sheet. Next, a substrate may be attached to the surface of the pressure-sensitive adhesive layer of the laminate opposite to the surface on the release sheet side, thereby obtaining a laminate of a pressure-sensitive adhesive sheet and a release sheet. The release sheet in the laminate may be released as a process material, or may be used to protect the adhesive layer until an adherend (e.g., a semiconductor chip, a semiconductor wafer, or the like) is bonded to the adhesive layer.

When the coating liquid contains a crosslinking agent, for example, a crosslinking reaction between the (meth) acrylic copolymer and the crosslinking agent in the coating film can be carried out by changing the drying conditions (for example, temperature and time) of the coating film or by separately performing a heat treatment, whereby a crosslinked structure can be formed in the pressure-sensitive adhesive layer at a desired density. In order to sufficiently progress the crosslinking reaction, the pressure-sensitive adhesive layer may be laminated on the substrate by the above-mentioned method or the like, and then the obtained pressure-sensitive adhesive sheet may be conditioned by leaving it to stand for several days in an environment of, for example, 23 ℃ and a relative humidity of 50%.

The thickness of the 1 st sheet 10 is preferably 30 μm or more, more preferably 50 μm or more. The thickness of the 1 st sheet 10 is preferably 400 μm or less, more preferably 300 μm or less.

(No. 2 adhesive sheet)

The 2 nd adhesive sheet 20 of the present embodiment has a 2 nd substrate 21 and a 2 nd adhesive layer 22. The 2 nd adhesive layer 22 is laminated on the 2 nd substrate 21.

No. 2 base Material

The material of the 2 nd base material 21 of the present embodiment is not particularly limited as long as it can function appropriately in a desired step such as a dicing step.

The 2 nd substrate 21 is preferably formed of a film mainly made of a resin material. Examples of the film mainly made of a resin material include: olefinic copolymer films, polyolefin films, polyvinyl chloride films, polyester films, polyurethane films, polyimide films, polystyrene films, polycarbonate films, and fluororesin films.

2 nd adhesive layer

The 2 nd pressure-sensitive adhesive layer 22 is not particularly limited in its constituent material as long as it can function properly in a desired step such as a dicing step.

The 2 nd pressure-sensitive adhesive layer 22 is preferably formed of at least one pressure-sensitive adhesive selected from the group consisting of an acrylic pressure-sensitive adhesive, a urethane pressure-sensitive adhesive, a polyester pressure-sensitive adhesive, a rubber pressure-sensitive adhesive, and a silicone pressure-sensitive adhesive, for example, and more preferably formed of an acrylic pressure-sensitive adhesive.

The 2 nd adhesive layer 22 may be formed of a non-energy ray curable adhesive or an energy ray curable adhesive.

[ Effect of the present embodiment ]

According to the sheet expanding method of the present embodiment, when the 1 st sheet 10 is stretched, the circuit surface W1 of the semiconductor chip CP is not in contact with the 1 st adhesive layer 12 of the 1 st sheet 10. Since the protective layer 100 singulated in the dicing step is interposed between the circuit surface W1 and the 1 st adhesive layer 12, the protective layer 100 in contact with the circuit surface W1 is not stretched even if the 1 st sheet 10 is stretched. As a result, according to the sheet expanding method of the present embodiment, the adhesive residue can be suppressed.

The pressure-sensitive adhesive sheet used in the sheet expanding method of the present embodiment has a simple structure including a substrate and a pressure-sensitive adhesive layer. Further, since the psa sheet used in the dicing step is transferred to the psa sheet used in the expanding step before the expanding step, it is not necessary to carefully control the depth of the cut so that the dicing blade does not reach the base material of the dicing sheet in the dicing step.

Therefore, according to the sheet expanding method of the present embodiment, the adhesive sheet structure and process can be simplified and adhesive residue can be suppressed compared to the conventional one.

Further, a method for manufacturing a semiconductor device including the film expanding method of the present embodiment can be provided.

[ 2 nd embodiment ]

Next, embodiment 2 of the present invention will be explained.

Embodiment 1 and embodiment 2 differ mainly in the following points. While the protective layer is provided on the 1 st object surface (circuit surface W1) of the object (semiconductor wafer W) in embodiment 1, the protective layer is provided on the object by bonding the 2 nd object surface (back surface W3) of the object (semiconductor wafer W) to the protective layer of the composite sheet including the protective layer and the 3 rd sheet in embodiment 2.

In the following description, the description will be given mainly of portions different from those of embodiment 1, and redundant description will be omitted or simplified. The same components as those in embodiment 1 are denoted by the same reference numerals, and descriptions thereof are omitted or simplified.

Fig. 6 (fig. 6A, 6B, and 6C) and fig. 7 (fig. 7A, 7B, and 7C) are schematic cross-sectional views illustrating a method for manufacturing a semiconductor device including the wafer expanding method according to the present embodiment.

The sheet expanding method according to the present embodiment includes the following steps (PX1) to (PX 5).

(PX1) and a step of bonding an object to be processed to the protective layer of the composite sheet having the protective layer and the 3 rd sheet.

(PX2) cutting the wafer by making a cut from the 1 st object surface side of the object, and then cutting at least the protective layer to singulate the plurality of semiconductor devices. The 1 st object plane becomes a circuit plane of the semiconductor device, and the 2 nd object plane becomes a back plane of the semiconductor device.

(PX3) and peeling the 3 rd sheet with the protective layer remaining on the back surface of the semiconductor device.

(PX4) a step of attaching the 1 st sheet to a protective layer on the back surface side of the semiconductor device.

(PX5) the step of stretching the 1 st sheet to expand the interval between the plurality of semiconductor devices.

(Compound sheet)

Fig. 6A shows a schematic cross-sectional view of a composite sheet 130 used in the present embodiment.

The composite sheet 130 has a protective layer 100A and a 3 rd sheet 30. The composite sheet 130 holds the semiconductor wafer W when the semiconductor wafer W is diced. The semiconductor wafer W is bonded with the back surface W3 facing the protective layer 100A of the composite sheet 130.

(protective layer)

The protective layer 100A in the composite sheet 130 is laminated on the 3 rd sheet 30. The protective layer 100A is not particularly limited as long as it can be bonded to the back surface W3 of the semiconductor wafer W as the object to be processed and the semiconductor chip CP as the semiconductor device (back surface of 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, more preferably 5 μm or more. The thickness of the protective layer 100A is preferably 500 μm or less, more preferably 300 μm or less.

The protective layer 100A may be the same protective layer as the protective layer 100 described in embodiment 1, for example.

(No. 3 sheet)

The 3 rd sheet 30 of the composite sheet 130 is a member supporting the protective layer 100A. The material of the 3 rd sheet 30 is not particularly limited as long as it can support the protective layer 100A. In the step (PX3) of the present embodiment, the 3 rd sheet 30 is peeled off while the protective layer 100A remains on the rear surface W3 of the semiconductor chip CP, and therefore, the 3 rd sheet 30 is preferably formed of a material or the like that can be peeled off from the protective layer 100A.

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

[ bonding Process of composite sheet ]

Fig. 6B is a diagram for explaining the process (PX 1). Fig. 6B shows the semiconductor wafer W to which the composite sheet 130 is bonded. The semiconductor wafer W in the present embodiment is also preferably a wafer obtained by performing a back grinding process. This step (PX1) may be referred to as a step of bonding the composite sheets.

As will be described later, in the step (PX2), the semiconductor wafer W is diced and singulated into a plurality of semiconductor chips CP. In the present embodiment, the composite sheet 130 is bonded to the rear surface W3 in order to hold the semiconductor wafer W during dicing of the semiconductor wafer W. The semiconductor wafer W is bonded with the back surface W3 facing the protective layer 100 of the composite sheet 130.

In the present embodiment, a description will be given by taking as an example a mode in which the process is performed in a state in which the circuit surface W1 is exposed, and as examples of other modes, for example: the process is performed in a state where a protective member such as a protective sheet or a protective film different from the protective layer 100A is bonded to the circuit surface W1.

[ cutting Process ]

Fig. 6C is a diagram for explaining the process (PX 2). The process (PX2) is sometimes referred to as a cutting process. A plurality of semiconductor chips CP held on the composite sheet 130 is shown in fig. 6C.

The semiconductor wafer W with the composite sheet 130 bonded to the rear surface W3 is diced and singulated to form a plurality of semiconductor chips CP. The circuit surface W1 as the 1 st semiconductor device surface corresponds to the circuit surface of the chip. The back surface W3 as the 2 nd semiconductor device surface corresponds to the chip back surface.

In the present embodiment, the semiconductor wafer W is cut by cutting a cut from the circuit surface W1 side, and at least the protective layer 100A of the composite sheet 130 is cut.

The cutting depth at the time of dicing is not particularly limited as long as the semiconductor wafer W and the protective layer 100A can be singulated. In the present embodiment, the embodiment has been described by way of example in which the 3 rd sheet 30 is not cut with a cut, but the present invention is not limited to such an embodiment. For example, in another embodiment, from the viewpoint of reliably cutting the semiconductor wafer W and the protective layer 100A, a cut mark may be formed by dicing to a depth reaching the 3 rd wafer 30.

[ peeling Process for the No. 3 sheet ]

Fig. 7A is a diagram for explaining the process (PX 3). The step (PX3) may be referred to as a 3 rd sheet separation step. Fig. 7A shows a process of peeling the 3 rd sheet 30 after the dicing process in a state where the protective layer 100A remains on the back surface W3 of the singulated semiconductor chip CP.

In a case where the protective layer 100A is directly laminated on the 3 rd sheet 30 as an embodiment of the composite sheet 130, the peeling is preferably performed at the interface between the protective layer 100A and the 3 rd sheet 30 in the peeling step of the 3 rd sheet. After the 3 rd sheet 30 is peeled off, a plurality of semiconductor chips CP having the protective layer 100A bonded to the back surface W3 can be obtained.

The peeling force when peeling the 3 rd sheet 30 from the protective layer 100A is preferably 10mN/25mm or more and 2000mN/25mm or less. When the peeling force at the time of peeling the 3 rd sheet 30 from the protective layer 100A is set to 10mN/25mm or more, the effect of excellent semiconductor chip holding property at the time of dicing can be obtained. By setting the peeling force at the time of peeling the 3 rd sheet 30 from the protective layer 100A to 2000mN/25mm or less, the effect of excellent pick-up property of the semiconductor chip after dicing can be obtained. The peeling force when peeling the 3 rd sheet 30 from the protective layer 100A is preferably 30mN/25mm or more and 1000mN/25mm or less, and more preferably 50mN/25mm or more and 500mN/25mm or less.

[ bonding Process of the first sheet ]

Fig. 7B is a diagram for explaining the process (PX 4). The step (PX4) may be referred to as a step of laminating the 1 st sheet. Fig. 7B shows a state where the 1 st sheet 10 is attached to the plurality of semiconductor chips CP obtained by the dicing process. The 1 st sheet 10 of the present embodiment is the same as the 1 st sheet 10 used in embodiment 1.

In the present embodiment, when the 1 st sheet 10 is attached to the rear surfaces W3 of the plurality of semiconductor chips CP, a laminated structure in which the singulated protective layer 100A is interposed between the plurality of semiconductor chips CP and the 1 st adhesive layer 12 of the 1 st sheet 10 can be obtained.

[ sheet expansion Process ]

Fig. 7C is a diagram for explaining the process (PX 5). The step (PX5) is sometimes referred to as a sheet expanding step. Fig. 7C shows a state in which the 1 st sheet 10 is stretched after the 1 st sheet 10 is attached, and the intervals between the plurality of semiconductor chips CP are enlarged.

In the sheet expanding step in the present embodiment, the method of stretching the 1 st sheet 10 is also the same as in embodiment 1. In the present embodiment, the interval D1 between the plurality of semiconductor chips CP is also not particularly limited since it depends on the size of the semiconductor chip CP. The distance D1 between adjacent semiconductor chips CP 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 mutual spacing of the semiconductor chips CP may be, for example, 6000 μm.

[ first transfer step ]

In the present embodiment, after the expanding step, a step of bonding the plurality of semiconductor chips CP bonded to the 1 st sheet 10 to the 6 th adhesive sheet 60 (hereinafter, may be referred to as "1 st transfer step") may be performed in the same manner as in embodiment 1.

In the case of performing the transfer step in the present embodiment, it is preferable that, for example, after the expanding step, the 6 th adhesive sheet 60 is bonded to the circuit surface W1 of the plurality of semiconductor chips CP, and thereafter the 1 st sheet 10 and the protective layer 100A are peeled off from the back surface W3. The 1 st sheet 10 and the protective layer 100A may be peeled off together from the rear surface W3, or the protective layer 100A may be peeled off from the rear surface W3 after the 1 st sheet 10 is peeled off. 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 distance D1 between the plurality of semiconductor chips CP expanded in the expanding step is maintained even after the peeling step of the protective layer 100A.

When the protective layer 100A is peeled off from the rear surface W3, the protective layer 100A preferably contains the 1 st energy ray-curable resin from the viewpoint of suppressing adhesive residue on the rear surface W3. When the protective layer 100A contains the 1 st energy ray-curable resin, the protective layer 100A is irradiated with an energy ray to cure the 1 st energy ray-curable resin. When the 1 st 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 ray (UV) and Electron Beam (EB), and preferably ultraviolet ray. Therefore, the 1 st energy ray-curable resin is preferably an ultraviolet ray-curable resin.

From the viewpoint of peeling the 1 st sheet 10 together with the protective layer 100A from the back surface W3, when the 1 st sheet 10 includes the 1 st pressure-sensitive adhesive layer 12, the 1 st pressure-sensitive adhesive layer 12 preferably contains the 2 nd energy ray-curable resin. When the protective layer 100A contains the 1 st energy ray-curable resin and the 1 st adhesive layer 12 contains the 2 nd energy ray-curable resin, the 1 st adhesive layer 12 and the protective layer 100A are irradiated with an energy ray from the 1 st substrate 11 side to cure the 2 nd energy ray-curable resin and the 1 st energy ray-curable resin. Examples of the energy ray for curing the 2 nd energy ray-curable resin include ultraviolet ray (UV) and Electron Beam (EB), and preferably ultraviolet ray. Therefore, the 2 nd energy ray-curable resin is preferably an ultraviolet ray-curable resin. The 1 st substrate 11 is preferably transparent to energy rays.

As an embodiment different from this embodiment, the protective layer 100A may be used as a protective film for protecting the rear surface W3 of the semiconductor chip CP without being peeled 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, the protective layer 100A preferably contains a curable adhesive composition.

[ sealing Process and other Processes ]

In this embodiment, the sealing step and other steps (the rewiring layer forming step and the step of connecting to the external terminal electrode) may be performed in the same manner as in embodiment 1.

(Compound sheet)

In one embodiment of the present embodiment, the protective layer 100A of the composite sheet 130 is preferably a 3 rd adhesive layer, and the 3 rd sheet 30 is preferably a 3 rd substrate. That is, the composite sheet 130 is preferably an adhesive sheet having the 3 rd substrate and the 3 rd adhesive layer and being peelable between the 3 rd substrate and the 3 rd adhesive layer.

No. 3 base Material

The material of the 3 rd base material of the present embodiment is not particularly limited as long as it can function properly in a desired process. The 3 rd substrate is a member supporting the 3 rd adhesive layer.

The 3 rd substrate is, for example, a resin film. As the resin film, at least any film selected from the group consisting of: for example, polyethylene films, polypropylene films, polybutylene films, polybutadiene films, polymethylpentene films, polyvinyl chloride films, vinyl chloride copolymer films, polyethylene terephthalate films, polyethylene naphthalate films, polybutylene terephthalate films, polyurethane films, ethylene-vinyl acetate copolymer films, ionomer resin films, ethylene- (meth) acrylic acid copolymer films, ethylene- (meth) acrylate copolymer films, polystyrene films, polycarbonate films, polyimide films, and fluororesin films. Further, as the 3 rd substrate, a crosslinked film thereof may be used. Further, the 3 rd substrate may be a laminated film of these films.

The 3 rd 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 wafers; epoxy resin materials, ABS resin, acrylic resin, engineering plastics, special engineering plastics, polyimide resin, polyamide-imide resin, and the like; and composite materials such as glass epoxy resins, and preferably SUS, glass, and silicon wafers. As the engineering plastics, there may be mentioned: nylon, Polycarbonate (PC), and polyethylene terephthalate (PET). As the special engineering plastics, there may be mentioned: polyphenylene Sulfide (PPS), polyether sulfone (PES), and polyether ether ketone (PEEK).

The thickness of the No. 3 substrate is not particularly limited. The thickness of the 3 rd base material is preferably 20 μm or more and 50mm or less, more preferably 60 μm or more and 20mm or less. When the thickness of the 3 rd base material is in the above range, the 3 rd sheet 30 has sufficient flexibility when the 3 rd base material is a resin film, and thus exhibits good adhesion to the object (workpiece). The object to be processed is, for example, a wafer or a semiconductor element, and more specifically, a semiconductor wafer or a semiconductor chip. When the 3 rd substrate is a hard support, the thickness of the hard support may be determined as appropriate in consideration of mechanical strength, handling properties, and the like. The thickness of the hard support is, for example, 100 μm or more and 50mm or less.

3 rd adhesive layer

The 3 rd pressure-sensitive adhesive layer is not particularly limited in its constituent material as long as it can function properly in a desired process.

In one embodiment of the 3 rd pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer is preferably formed of at least one pressure-sensitive adhesive selected from the group consisting of an acrylic pressure-sensitive adhesive, a urethane pressure-sensitive adhesive, a polyester pressure-sensitive adhesive, a rubber pressure-sensitive adhesive, and a silicone pressure-sensitive adhesive, and more preferably formed of an acrylic pressure-sensitive adhesive.

In one embodiment of the 3 rd adhesive layer, the adhesive layer preferably contains a curable adhesive composition which is cured by receiving energy from the outside. Examples of the energy supplied from the outside include: ultraviolet rays, electron beams, heat, and the like. The 3 rd pressure-sensitive adhesive layer preferably contains at least one of an ultraviolet-curable pressure-sensitive adhesive and a heat-curable pressure-sensitive adhesive. When the 3 rd substrate has heat resistance, the adhesive layer is preferably a thermosetting adhesive layer containing a thermosetting adhesive because the generation of residual stress during thermosetting can be suppressed.

The 3 rd adhesive layer contains, for example, a first adhesive composition. The first adhesive composition contains an adhesive polymer component (a) and a curable component (B).

(A) Adhesive polymer composition

In order to impart sufficient adhesiveness and film-forming property (sheet-forming property) to the 3 rd adhesive layer, the adhesive polymer component (a) may be used. As the binder polymer component (a), conventionally known acrylic polymers, polyester resins, urethane resins, acrylic urethane resins, silicone resins, rubber polymers, and the like can be used.

The weight average molecular weight (Mw) of the binder polymer component (a) is preferably 1 ten thousand or more and 200 ten thousand or less, more preferably 10 ten thousand or more and 120 ten thousand or less. In the present specification, the weight average molecular weight (Mw) is a value converted to standard polystyrene as measured by a Gel Permeation Chromatography (GPC) method.

As the binder polymer component (a), an acrylic polymer can be preferably used. The glass transition temperature (Tg) of the acrylic polymer is preferably in the range of-60 ℃ to 50 ℃, more preferably-50 ℃ to 40 ℃, and still more preferably-40 ℃ to 30 ℃.

Examples of the monomer forming the acrylic polymer include a (meth) acrylate monomer and a derivative thereof. For example, alkyl (meth) acrylates having an alkyl group of 1 to 18 carbon atoms include, specifically: methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and the like. Further, there may be mentioned (meth) acrylates having a cyclic skeleton, and specifically: cyclohexyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, imide (meth) acrylate, and the like. Further, as the monomer having a functional group, there can be mentioned: hydroxymethyl (meth) acrylate having a hydroxyl group, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and the like; and glycidyl (meth) acrylate having an epoxy group. Among the acrylic polymers, an acrylic polymer containing a monomer having a hydroxyl group is preferable because of good compatibility with the curable component (B) described later. The acrylic polymer may be copolymerized with at least one selected from acrylic acid, methacrylic acid, itaconic acid, vinyl acetate, acrylonitrile, and styrene.

Further, as the adhesive polymer component (a), a thermoplastic resin for retaining the flexibility of the film of the cured 3 rd adhesive layer may be blended. The thermoplastic resin is preferably a resin having a weight average molecular weight of 1000 to 10 ten thousand, more preferably 3000 to 8 ten thousand. The glass transition temperature of the thermoplastic resin is preferably-30 ℃ or higher and 120 ℃ or lower, and more preferably-20 ℃ or higher and 120 ℃ or lower. As the thermoplastic resin, there can be mentioned: polyester resin, urethane resin, phenoxy resin, polybutylene, polybutadiene, polystyrene, or the like. These thermoplastic resins may be used singly or in combination of two or more.

(B) Curable component

As the curable component (B), at least any one of a thermosetting component and an energy ray curable component can be used. As the curable component (B), a thermosetting component and an energy ray curable component can be used.

As the thermosetting component, a thermosetting resin and a thermosetting agent can be used. As the thermosetting resin, for example, an epoxy resin is preferable.

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 ethers or hydrogenated products thereof, o-cresol novolac epoxy resins, dicyclopentadiene epoxy resins, biphenyl epoxy resins, bisphenol a epoxy resins, bisphenol F epoxy resins, phenylene skeleton epoxy resins, and the like, having a bifunctional or higher in the molecule. These epoxy resins may be used singly or in combination of two or more.

In the 3 rd adhesive layer, the content of the thermosetting resin is preferably 1 part by weight or more and 1000 parts by weight or less, more preferably 10 parts by weight or more and 500 parts by weight or less, and further preferably 20 parts by weight or more and 200 parts by weight or less, with respect to 100 parts by weight of the adhesive polymer component (a). When the content of the thermosetting resin is 1 part by weight or more, such a disadvantage that sufficient adhesiveness cannot be obtained can be suppressed. When the content of the thermosetting resin is 1000 parts by weight or less, the peeling force between the 3 rd adhesive layer and the 3 rd substrate can be prevented from becoming excessively high. If the peeling force can be prevented from becoming too high, transfer failure of the 3 rd adhesive layer to the back surface W3 of the semiconductor chip CP can be prevented.

The thermosetting agent functions as a curing agent for thermosetting resins, particularly epoxy resins. As a preferable thermal curing agent, a compound having 2 or more functional groups reactive with an epoxy group in 1 molecule is exemplified. Examples of the functional group capable of reacting with an epoxy group include a phenolic hydroxyl group, an alcoholic hydroxyl group, an amino group, a carboxyl group, and an acid anhydride group. Among these functional groups, preferred are a phenolic hydroxyl group, an amino group, an acid anhydride group, and the like, and more preferred are a phenolic hydroxyl group and an amino group.

Specific examples of the phenol curing agent include polyfunctional phenol resins, biphenols, novolak-type phenol resins, dicyclopentadiene-type phenol resins, XYLOCK-type phenol resins, and aralkyl phenol resins. Specific examples of the amine-based curing agent include DICY (dicyandiamide). These heat-curing agents may be used singly or in combination of two or more.

The content of the thermosetting agent is preferably 0.1 part by weight or more and 500 parts by weight or less, more preferably 1 part by weight or more and 200 parts by weight or less, with respect to 100 parts by weight of the thermosetting resin.

When the 3 rd adhesive layer contains a thermosetting component as the curable component (B), the 3 rd adhesive layer has thermosetting properties. In this case, the 3 rd pressure-sensitive adhesive layer can be cured by heating, but in the case where the 3 rd base material has heat resistance, the 1 st sheet 10 of the present embodiment has a problem that residual stress is not likely to occur in the base material and cause troubles when the 3 rd pressure-sensitive adhesive layer is thermally cured.

As the energy ray-curable component, a low molecular weight compound (energy ray-polymerizable compound) containing an energy ray-polymerizable group and being polymerizable and curable upon irradiation with an energy ray such as ultraviolet ray or electron beam can be used. Specific examples of such energy ray-curable components include: acrylate compounds such as trimethylolpropane triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, or 1, 4-butanediol diacrylate, 1, 6-hexanediol diacrylate, polyethylene glycol diacrylate, oligoester acrylate, urethane acrylate oligomer, epoxy-modified acrylate, polyether acrylate, and itaconic acid oligomer. Such a compound has at least 1 polymerizable double bond in the molecule, and the weight average molecular weight is usually 100 or more and 30000 or less, preferably 300 or more and 10000 or less. The amount of the energy ray-polymerizable compound blended is preferably 1 part by weight or more and 1500 parts by weight or less, more preferably 10 parts by weight or more and 500 parts by weight or less, and further preferably 20 parts by weight or more and 200 parts by weight or less, with respect to 100 parts by weight of the binder polymer component (a).

As the energy ray-curable component, an energy ray-curable polymer in which an energy ray-polymerizable group is bonded to the main chain or side chain of the binder polymer component (a) can be used. Such an energy ray-curable polymer has both a function as the binder polymer component (a) and a function as the curable component (B).

The main skeleton of the energy ray-curable polymer is not particularly limited, and may be an acrylic polymer commonly used as the binder polymer component (a), or may be a polyester, polyether or the like, but an acrylic polymer is preferably used as the main skeleton in view of easy synthesis and control of physical properties.

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 and the like. 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.

The weight average molecular weight (Mw) of the energy ray-curable polymer to which the energy ray-polymerizable group is bonded is preferably 1 to 200 ten thousand, more preferably 10 to 150 ten thousand. The glass transition temperature (Tg) of the energy ray-curable polymer is preferably-60 ℃ or higher and 50 ℃ or lower, more preferably-50 ℃ or higher and 40 ℃ or lower, and still more preferably-40 ℃ or higher and 30 ℃ or lower.

The energy ray-curable polymer can be obtained by, for example, reacting an acrylic polymer having a functional group with a polymerizable group-containing compound. Examples of the functional group-containing acrylic polymer include: hydroxyl, carboxyl, amino, substituted amino, and epoxy groups. The polymerizable group-containing compound is a polymerizable group-containing compound having 1 to 5 substituents reactive with the substituent of the acrylic polymer and an energy ray-polymerizable carbon-carbon double bond per 1 molecule. Examples of the substituent reactive with the functional group include an isocyanate group, a glycidyl group, and a carboxyl group.

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

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

Examples of the (meth) acrylic monomer having a functional group such as a hydroxyl group, a carboxyl group, an amino group, a substituted amino group, and an epoxy group, or a derivative thereof include: 2-hydroxyethyl (meth) acrylate having a hydroxyl group, 2-hydroxypropyl (meth) acrylate; acrylic acid, methacrylic acid, itaconic acid having a carboxyl group; glycidyl methacrylate, glycidyl acrylate, etc. having an epoxy group.

Examples of the other (meth) acrylic acid ester monomer or derivative thereof copolymerizable with the (meth) acrylic acid monomer include alkyl (meth) acrylates having an alkyl group of 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 the other (meth) acrylate monomer or derivative thereof copolymerizable with the (meth) acrylic acid monomer include (meth) acrylates having a cyclic skeleton, and specific examples thereof include: cyclohexyl (meth) acrylate, benzyl (meth) acrylate, isobornyl acrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, imide acrylate, and the like. The acrylic polymer may be copolymerized with at least any monomer selected from vinyl acetate, acrylonitrile, and styrene.

When an energy ray-curable polymer is used, the energy ray-polymerizable compound described above may be used in combination, or the binder polymer component (a) may be used in combination. The content of the energy ray-polymerizable compound in the 3 rd pressure-sensitive adhesive layer of the present embodiment is preferably 1 part by weight or more and 1500 parts by weight or less, more preferably 10 parts by weight or more and 500 parts by weight or less, and still more preferably 20 parts by weight or more and 200 parts by weight or less, based on 100 parts by weight of the total of the mass of the energy ray-curable polymer and the pressure-sensitive adhesive polymer component (a).

By imparting energy ray curability to the 3 rd adhesive layer, the 3 rd adhesive layer can be cured easily and in a short time, and the production efficiency of chips with a cured adhesive layer can be improved. The cured adhesive layer may also function as a protective film for protecting the semiconductor element. Conventionally, a protective film for a semiconductor element such as a chip is generally formed of a thermosetting resin such as an epoxy resin, but the curing temperature of the thermosetting resin exceeds 200 ℃ and the curing time takes about 2 hours, which is an obstacle to improvement of production efficiency. However, since the energy ray-curable adhesive layer can be cured in a short time by irradiation with an energy ray, a protective film can be formed easily, which can contribute to improvement of production efficiency.

Other ingredients

The 3 rd adhesive layer may contain the following components in addition to the adhesive polymer component (a) and the curable component (B).

(CX) coloring agent

The 3 rd adhesive layer contains a Colorant (CX) in one embodiment. When the colorant is mixed into the 3 rd adhesive layer, and the 3 rd adhesive layer is cured to form the protective film of the semiconductor chip CP, the protective film shields infrared rays and the like generated from surrounding devices when the semiconductor device is assembled in a facility, and thus malfunction of the semiconductor device due to the infrared rays and the like can be prevented. Further, the visibility of characters when printing the product number or the like is improved in the cured pressure-sensitive adhesive layer (protective film) obtained by curing the 3 rd pressure-sensitive adhesive layer containing the Colorant (CX). That is, in a semiconductor device or a semiconductor chip on which a protective film is formed, printing of a product number or the like is generally performed on the surface of the protective film by a laser marking method (a method of printing by cutting off the surface of the protective film with laser light). By including the Colorant (CX) in the protective film, a difference in contrast between the portion of the protective film which is removed by the laser beam and the portion which is not removed can be sufficiently obtained, and visibility can be improved. As the Colorant (CX), at least any of organic pigments, inorganic pigments, organic dyes, and inorganic dyes can be used. The Colorant (CX) is preferably a black pigment from the viewpoint of electromagnetic wave and infrared shielding properties. As the black pigment, carbon black, iron oxide, manganese dioxide, aniline black, activated carbon, and the like can be used, but the black pigment is not limited thereto. In particular, carbon black is preferable as the Colorant (CX) in view of improving the reliability of the semiconductor device. The coloring agent (CX) may be used alone or in combination of two or more. The high curability of the 3 rd adhesive layer in the present embodiment is particularly preferably exhibited when the ultraviolet transmittance is reduced by using a colorant capable of reducing the ultraviolet transmittance as well as at least one of visible light and infrared light. The colorant that can reduce the transmittance of ultraviolet light as well as at least either of visible light and infrared light is not particularly limited as long as it is a colorant that has an absorbing or reflecting property in both the wavelength ranges of ultraviolet light and at least either of visible light and infrared light, in addition to the above-described black pigment.

The amount of the Colorant (CX) is preferably 0.1 part by weight or more and 35 parts by weight or less, more preferably 0.5 part by weight or more and 25 parts by weight or less, and still more preferably 1 part by weight or more and 15 parts by weight or less, based on 100 parts by weight of the total solid content constituting the 3 rd adhesive layer.

(D) Curing accelerator

The curing accelerator (D) is used to adjust the curing speed of the 3 rd adhesive layer. The curing accelerator (D) is preferably used particularly when an epoxy resin and a heat curing agent are used in combination in the curable component (B).

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; tetraphenylboron salts such as tetraphenylphosphonium tetraphenylboron and triphenylphosphine tetraphenylboron. These curing accelerators may be used singly or in combination of two or more.

The content of the curing accelerator (D) is preferably 0.01 part by weight or more and 10 parts by weight or less, and more preferably 0.1 part by weight or more and 1 part by weight or less, with respect to 100 parts by weight of the curable component (B).

(EX) coupling Agents

The coupling agent (EX) can be used to improve at least any of the adhesiveness and adhesiveness of the 3 rd adhesive layer to the semiconductor element and the cohesive property of the cured adhesive layer (protective film). Further, by using the coupling agent (EX), the water resistance of the cured adhesive layer (protective film) obtained by curing the 3 rd adhesive layer can be improved without impairing the heat resistance.

As the coupling agent (EX), a compound having a group reactive with a functional group of the binder polymer component (a), the curable component (B), or the like can be preferably used. The coupling agent (EX) is preferably a silane coupling agent. Examples of such coupling agents include: gamma-glycidoxypropyltrimethoxysilane, gamma-glycidoxypropylmethyldiethoxysilane, beta- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, gamma- (methacryloxypropyl) trimethoxysilane, gamma-aminopropyltrimethoxysilane, N-6- (aminoethyl) -gamma-aminopropylmethyldiethoxysilane, N-phenyl-gamma-aminopropyltrimethoxysilane, gamma-ureidopropyltriethoxysilane, gamma-mercaptopropyltrimethoxysilane, gamma-mercaptopropylmethyldimethoxysilane, bis (3-triethoxysilylpropyl) tetrasulfide, N-phenylthiodiglycol, N-glycidoxypropyltrimethoxysilane, gamma-mercaptopropylmethyldimethoxysilane, N-glycidoxypropyltrimethoxysilane, gamma-glycidoxypropyltrimethoxysilane, beta-glycidoxypropyltrimethoxysilane, gamma-glycidoxypropyltrimethoxysilane, beta-glycidoxypropyltrimethoxysilane, gamma-glycidoxypropyltriethoxysilane, gamma-glycidoxypropyl-tert-octadecyloxysilane, beta-glycidoxypropyl-octyltrimethoxysilane, gamma-glycidoxypropyl-tert-octyltrimethoxysilane, gamma-butyltrimethoxysilane, gamma-octyltrimethoxysilane, gamma-butyltrimethoxysilane, gamma-octyltrimethoxysilane, gamma-tert-octyltrimethoxysilane, gamma-butyltrimethoxysilane, gamma-octyltrimethoxysilane, gamma-butyltrimethoxysilane, gamma-octyltrimethoxysilane, gamma-butyltrimethoxysilane, gamma-octyltrimethoxysilane, gamma-butyltrimethoxysilane, gamma-butyl, Methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, imidazolesilane and the like. These coupling agents (EX) may be used singly or in combination of two or more.

The content of the coupling agent (EX) is usually 0.1 to 20 parts by weight, preferably 0.2 to 10 parts by weight, and more preferably 0.3 to 5 parts by weight, based on 100 parts by weight of the total of the binder polymer component (a) and the curable component (B).

(F) Inorganic filler

By adding the inorganic filler (F) to the 3 rd pressure-sensitive adhesive layer, the thermal expansion coefficient of the cured pressure-sensitive adhesive layer (protective film) after curing can be adjusted.

Preferred inorganic fillers include powders of silica, alumina, talc, calcium carbonate, titanium oxide, iron oxide, silicon carbide, boron nitride, and the like, beads obtained by spheroidizing these powders, single crystal fibers, glass fibers, and the like. Among these inorganic fillers, silica fillers and alumina fillers are preferable. The inorganic filler (F) may be used singly or in combination of two or more kinds. The content of the inorganic filler (F) may be adjusted within a range of usually not less than 1 part by weight and not more than 80 parts by weight with respect to 100 parts by weight of the total solid content constituting the adhesive layer.

(G) Photopolymerization initiator

When the energy ray-curable component is contained as the curable component (B) in the 3 rd adhesive layer, the energy ray-curable component is cured by irradiation with an energy ray such as ultraviolet ray. In this case, by adding the photopolymerization initiator (G) to the composition constituting the 3 rd pressure-sensitive adhesive layer, the polymerization curing time can be shortened, and the amount of light irradiation can be reduced.

Examples of such photopolymerization initiators (G) include: benzophenone, acetophenone, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoylbenzoic acid methyl ester, benzoin dimethyl ether, 2, 4-diethyl thiazolone, α -hydroxycyclohexyl phenyl ketone, benzyl diphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzil, bibenzyl, butanedione, 1, 2-diphenylmethane, 2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl ] acetone, 2,4, 6-trimethylbenzoyl diphenyl phosphine oxide, β -chloroanthraquinone, and the like. The photopolymerization initiator (G) may be used alone or in combination of two or more.

The blending ratio of the photopolymerization initiator (G) is preferably 0.1 part by weight or more and 10 parts by weight or less, more preferably 1 part by weight or more and 5 parts by weight or less, with respect to 100 parts by weight of the energy ray-curable component. When the proportion of the photopolymerization initiator (G) is 0.1 parts by weight or more, such a disadvantage that satisfactory transferability cannot be obtained due to insufficient photopolymerization can be prevented. When the blending ratio of the photopolymerization initiator (G) is 10 parts by weight or less, it is possible to prevent the generation of residues unfavorable for photopolymerization and the insufficient curability of the 3 rd pressure-sensitive adhesive layer.

(H) Crosslinking agent

In order to adjust the initial adhesive force and cohesive force of the 3 rd adhesive layer, a crosslinking agent may be added to the 3 rd adhesive layer. Examples of the crosslinking agent (H) include an organic polyisocyanate compound and an organic polyimine compound.

Examples of the organic polyisocyanate compound include: aromatic polyisocyanate compounds, aliphatic polyisocyanate compounds, alicyclic polyisocyanate compounds, trimers of these organic polyisocyanate compounds, isocyanate-terminated urethane prepolymers obtained by reacting these organic polyisocyanate compounds with polyol compounds, and the like.

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.

Examples of the organic polyimine compound include: n, N ' -diphenylmethane-4, 4 ' -bis (1-aziridinecarboxamide), trimethylolpropane tris (β -aziridinylpropionate), tetramethylolmethane tris (β -aziridinylpropionate), and N, N ' -toluene-2, 4-bis (1-aziridinecarboxamide) triethylenemelamine.

The crosslinking agent (H) is used in a proportion of usually 0.01 to 20 parts by weight, preferably 0.1 to 10 parts by weight, and more preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the total amount of the binder polymer component (a) and the energy ray-curable polymer.

(I) Universal additive

In addition to the above components, various additives may be added to the adhesive layer 3 as needed. Examples of the various additives include: leveling agent, plasticizer, antistatic agent, antioxidant, ion trapping agent, getter, chain transfer agent and the like.

The 3 rd adhesive layer containing the components described above has adhesiveness and curability, and is easily adhered by pressing an object to be processed (a semiconductor wafer, a chip, or the like) in an uncured state. The 3 rd pressure-sensitive adhesive layer may have a single-layer structure, or may have a multi-layer structure as long as it contains one or more layers containing the above components.

The thickness of the 3 rd adhesive layer is not particularly limited. The thickness of the 3 rd 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 further preferably 7 μm or more and 200 μm or less.

The above is the description about the 3 rd adhesive layer.

Peeling 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 3 rd adhesive layer of the composite sheet 130. The release sheet is attached to the surface of the 3 rd pressure-sensitive adhesive layer to protect the 3 rd pressure-sensitive adhesive layer during transportation and storage. The release sheet is releasably attached to the composite sheet 130 and is released and removed from the composite sheet 130 before the composite sheet 130 is used.

The release sheet may be one having at least one surface subjected to a release treatment. Specifically, for example, a release sheet is provided with a release sheet substrate and a release agent layer formed by applying a release agent to the surface of the substrate.

[ Effect of the present embodiment ]

According to the sheet expanding method of the present embodiment, when the 1 st sheet 10 is stretched, the back surface W3 of the semiconductor chip CP and the 1 st adhesive layer 12 of the 1 st sheet 10 are not in contact with each other. Since the protective layer 100A singulated in the dicing step is interposed between the back surface W3 and the 1 st adhesive layer 12, the 1 st adhesive layer 12 in contact with the back surface W3 is not stretched even if the 1 st sheet 10 is stretched. As a result, according to the sheet expanding method of the present embodiment, the adhesive residue can be suppressed.

In the present embodiment, the semiconductor wafer W is not supported by the dicing sheet but supported by the composite sheet 130 in the dicing step. Therefore, in order to form a layer (the protective layer 100A in the present embodiment) for protecting the rear surface W3 of the semiconductor chip CP after dicing, a layer for protecting the rear surface W3 can be formed as long as peeling can be performed between the protective layer 100A and the 3 rd sheet 30 without performing a step of transferring an adhesive sheet used in the dicing step to another adhesive sheet.

Further, before the expanding step is performed, it is not necessary to carefully control the depth of the cut so that the dicing blade does not reach the base material of the dicing sheet in the dicing step in order to transfer the adhesive sheet used in the dicing step to the adhesive sheet for the expanding step.

Therefore, according to the sheet expanding method of the present embodiment, the tape structure and process can be simplified and the adhesive residue can be suppressed as compared with the conventional method.

Further, a method for manufacturing a semiconductor device including the wafer expanding method according to the present embodiment can be provided.

[ embodiment 3 ]

Next, embodiment 3 of the present invention will be described.

Embodiment 1 and embodiment 3 differ mainly in the following points.

In embodiment 1, a protective layer is provided on the 1 st object surface (circuit surface W1) of the object to be processed (semiconductor wafer W), and the object to be processed (semiconductor wafer W) is transferred from the dicing sheet (the 2 nd adhesive sheet 20) to the extending sheet (the 1 st sheet) after the dicing step and before the extending step. On the other hand, in embodiment 3, the 2 nd object surface (back surface W3) of the object to be processed (semiconductor wafer W) is bonded to the protective layer of the composite sheet including the protective layer and the 1 st sheet, whereby the protective layer is provided on the object to be processed, and the sheet expanding step is performed without the 1 st sheet being transferred to another sheet after the dicing step.

The sheet expanding method according to the present embodiment includes the following steps (PY1) to (PY 3).

(PY1) A step of bonding an object to be processed to the protective layer of the composite sheet comprising the protective layer and the 1 st sheet. The protective layer has substantially the same shape as the object.

(PY2) cutting the wafer by cutting a notch from the 1 st object surface side of the object, and then cutting at least the protective layer to singulate the plurality of semiconductor devices. The 1 st object plane becomes a circuit plane of the semiconductor device, and the 2 nd object plane becomes a back plane of the semiconductor device.

(PY3) stretching the 1 st piece to expand the intervals between the plurality of semiconductor devices.

Fig. 8 (fig. 8A, 8B, and 8C) and 9 are schematic cross-sectional views illustrating a method for manufacturing a semiconductor device including the wafer expanding method according to the present embodiment.

(Compound sheet)

Fig. 8A shows a schematic cross-sectional view of a composite sheet 140 used in the present embodiment.

The composite sheet 140 has a protective layer 100B and a1 st sheet 10. The composite sheet 140 holds the semiconductor wafer W when the semiconductor wafer W is diced, and the composite sheet 140 holds the semiconductor chips CP when the expanding step is performed. The semiconductor wafer W is bonded with the back surface W3 facing the protective layer 100B of the composite sheet 140.

The 1 st sheet 10 and the protective layer 100B bonded to the back surface W3 are preferably a laminated composite sheet 140 laminated in advance.

(protective layer)

The protective layer 100B in the composite sheet 140 is laminated on the 1 st sheet 10. The protective layer 100B is not particularly limited as long as it can be bonded to the back surface W3 of the semiconductor wafer W as the object to be processed and the semiconductor chip CP as the semiconductor device (back surface of the semiconductor device) to protect the back surface W3.

In the present embodiment, the protective layer 100B has substantially the same shape as the back surface W3 of the semiconductor wafer W. The protective layer 100B is preferably shaped to cover the back surface W3 of the semiconductor wafer W. Therefore, the protective layer 100B is preferably formed substantially the same as the rear surface W3 of the semiconductor wafer W or slightly larger than the rear surface W3.

In addition, the protective layer 100B is preferably formed to be smaller than the 1 st sheet 10 in the sheet in-plane direction. A jig such as a ring frame may be attached to a portion of the 1 st adhesive layer 12 of the 1 st sheet 10 where the protective layer 100B is not laminated.

The protective layer 100B of the present embodiment is formed of a single layer. The protective layer 100B may be a sheet formed by laminating a plurality of layers. The protective layer 100B is preferably formed of a single layer from the viewpoint of ease of control of light transmittance and manufacturing cost.

The thickness of the protective layer 100B is preferably 1 μm or more, more preferably 5 μm or more. The thickness of the protective layer 100B is preferably 500 μm or less, more preferably 300 μm or less.

Examples of the protective layer 100B include a protective film and a protective sheet. The protective layer 100B may be, for example, the same protective layer as the protective layer 100 described in embodiment 1. Further, another embodiment different from the protective layer 100B will be described later.

(the 1 st sheet)

The 1 st sheet 10 of the composite sheet 140 is a member supporting the protective layer 100B. The material of the 1 st sheet 10 is not particularly limited as long as it can support the protective layer 100B.

The 1 st sheet 10 of the composite sheet 140 has a1 st adhesive layer 12 and a1 st substrate 11. The 1 st sheet 10 is the same as the 1 st sheet 10 of embodiment 1.

In the present embodiment, when the 1 st sheet 10 is made of a material or the like that can be peeled off from the protective layer 100B, the 1 st sheet 10 may be peeled off while the protective layer 100B remains on the back surface W3 of the semiconductor chip CP.

[ bonding Process of composite sheet ]

Fig. 8B is a diagram for explaining the step (PY 1). Fig. 8B shows a semiconductor wafer W to which a composite sheet 140 having the 1 st sheet 10 and the protective layer 100B is bonded. The semiconductor wafer W in the present embodiment is also preferably a wafer obtained by performing a back grinding process. This step (PY1) may be referred to as a step of bonding the composite sheets.

As described later, in the process (PY2), the semiconductor wafer W is diced and singulated into a plurality of semiconductor chips CP. In the present embodiment, the composite sheet 140 is bonded to the rear surface W3 in order to hold the semiconductor wafer W during dicing of the semiconductor wafer W. The semiconductor wafer W is bonded 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 rear surface W3, and can cover the rear surface W3. In the present embodiment, the protective layer 100B is sandwiched between the semiconductor wafer W and the 1 st sheet 10.

In the present embodiment, a description will be given by taking as an example a mode in which the process is performed in a state in which the circuit surface W1 is exposed, and as examples of other modes, for example: the process is performed in a state where a protective member such as a protective sheet or a protective film different from the protective layer 100B is bonded to the circuit surface W1.

The step of bonding the 1 st sheet 10 and the protective layer 100B to the rear surface W3 is not limited to the embodiment using the laminated composite sheet 140, and may be, for example, a method in which the protective layer 100B is bonded to the rear surface W3 of the semiconductor wafer W, and then the 1 st sheet 10 is bonded to the protective layer 100B.

[ cutting Process ]

Fig. 8C is a diagram for explaining the step (PY 2). The process (PY2) is sometimes referred to as a cutting process. A plurality of semiconductor chips CP held on the 1 st sheet 10 are shown in fig. 8C.

The semiconductor wafer W having the 1 st sheet 10 and the protective layer 100B bonded to the rear surface W3 is diced and singulated to form a plurality of semiconductor chips CP.

In this embodiment, the semiconductor wafer W is cut by cutting a cut from the circuit surface W1 side, and then the protective layer 100B is cut so that the cut reaches the 1 st pressure-sensitive adhesive layer 12. By this dicing, the protective layer 100B is also cut to the same size as the semiconductor chip CP.

The cutting depth at the time of cutting is not particularly limited as long as the semiconductor wafer W and the protective layer 100B can be singulated. In the present embodiment, the embodiment in which the cut line is not cut to the 1 st base material 11 is described as an example, but the present invention is not limited to such an embodiment. For example, in another embodiment, from the viewpoint of more reliably cutting the semiconductor wafer W and the protective layer 100B, a cut mark may be formed by dicing to a depth reaching the 1 st base material 11. Further, the protective layer 100B may be cut without causing the cut to reach the 1 st pressure-sensitive adhesive layer 12.

In the present embodiment, a laminated structure in which the singulated protective layer 100B is interposed between the plurality of semiconductor chips CP and the 1 st adhesive layer 12 of the 1 st sheet 10 on the rear surface W3 side of the semiconductor chip CP can be obtained by the dicing step.

[ sheet expansion Process ]

Fig. 9 is a diagram for explaining the step (PY 3). The step (PY3) may be referred to as a sheet expanding step. Fig. 9 shows a state in which the 1 st piece 10 is stretched after the dicing process to expand the intervals of the plurality of semiconductor chips CP.

[ transfer step, sealing step and other steps ]

In this embodiment, as in

embodiment

1 or 2, the transfer step, the sealing step, and other steps (the rewiring layer forming step and the connection step with the external terminal electrode) can be performed.

(protective layer)

In one embodiment of the protective layer 100B, the adhesive is preferably an uncured curable adhesive. In this case, by laminating the object to be processed (workpiece) such as the semiconductor wafer W on the protective layer 100B and then curing the protective layer 100B, a cured product (protective film) of the protective layer 100B can be strongly adhered to the object to be processed, and a protective film having durability against a semiconductor device such as the semiconductor chip CP can be formed.

The protective layer 100B preferably has adhesiveness at normal temperature or exhibits adhesiveness by heating. Thus, when the object to be processed such as the semiconductor wafer W is laminated on the protective layer 100B as described above, the object to be processed and the protective layer can be bonded to each other. Therefore, positioning can be reliably performed before the protective layer 100B is cured.

The curable adhesive constituting the protective layer 100B having the above-described 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 a thermosetting component is particularly preferably used. That is, the protective layer 100B is preferably formed of a thermosetting adhesive.

As a thermosetting component, a thermosetting resin,examples thereof include: epoxy resin, phenol resin, melamine resin, urea resin, polyester resin, urethane resin, acrylic resin, polyimide resin, and benzo

Oxazine resins, and the like, and mixtures thereof. Among these resins, as the thermosetting component, an epoxy resin, a phenol resin, and a mixture thereof can be preferably used.

Epoxy resins have the property of forming a three-dimensional network when heated, and forming a strong coating film. As such an epoxy resin, various epoxy resins known from the past can be used. The epoxy resin having a number average molecular weight of about 300 to 2000 is preferable, and the epoxy resin having a number average molecular weight of 300 to 500 is more preferable. Further preferably, a blend type epoxy resin is used, which is obtained by blending an epoxy resin that is liquid in a normal state and has a number average molecular weight of 330 to 400 with an epoxy resin that is solid at normal temperature and has a number average molecular weight of 400 to 2500 (preferably 500 to 2000). The epoxy equivalent of the epoxy resin is preferably 50 to 5000 g/eq. The number average molecular weight of the epoxy resin can be determined by a method using GPC.

Specific examples of such epoxy resins include: glycidyl ethers of phenols such as bisphenol a, bisphenol F, resorcinol, phenol 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-type or alkyl glycidyl-type epoxy resins in which active hydrogen bonded to a nitrogen atom such as aniline isocyanurate is replaced with a glycidyl group; so-called alicyclic epoxy oxides obtained by introducing an epoxy group to a carbon-carbon double bond in the molecule by, for example, oxidation, such as vinylcyclohexane diepoxide, 3, 4-epoxycyclohexylmethyl-3, 4-bicyclohexane formate, and 2- (3, 4-epoxy) cyclohexyl-5, 5-spiro (3, 4-epoxy) cyclohexane-m-dioxane. Further, for example, an epoxy resin having at least one skeleton selected from a biphenyl skeleton, a dicyclohexyldiene skeleton, and a naphthalene skeleton may be used.

Among specific examples of these epoxy resins, bisphenol-type glycidyl epoxy resins, o-cresol novolac epoxy resins, and phenol novolac epoxy resins are preferably used as the epoxy resin. These epoxy resins may be used singly or in combination of two or more.

When an epoxy resin is used, it is preferable to use a heat-activated latent epoxy resin curing agent in combination as an auxiliary agent. The heat-activated latent epoxy resin curing agent is a curing agent which does not react with an epoxy resin at room temperature, and is activated by heating to a temperature higher than a predetermined temperature to react with the epoxy resin. The activation method of the heat-activated latent epoxy resin curing agent comprises the following steps: a method of generating active species (anion, cation) by a chemical reaction based on heating; a method of stably dispersing in an epoxy resin at around room temperature and being compatible/soluble with the epoxy resin at high temperature to initiate a curing reaction; a method in which a molecular sieve-encapsulated curing agent is dissolved out at a high temperature to initiate a curing reaction; a method using a microcapsule, and the like.

Specific examples of the heat-activated latent epoxy resin curing agent include: various kinds of

And high-melting active hydrogen compounds such as salts, dibasic acid dihydrazide compounds, dicyandiamide, amine adduct curing agents, imidazole compounds, and the like. These heat-activated latent epoxy resin curing agents may be used singly or in combination of two or more. The proportion of the heat-activated latent epoxy resin curing agent used is preferably 0.1 to 20 parts by weight, more preferably 0.2 to 10 parts by weight, and still more preferably 0.3 to 5 parts by weight, based on 100 parts by weight of the epoxy resin.

The phenol resin may be, but is not limited to, a condensate of a phenol such as an alkylphenol, a polyphenol, or naphthol, and an aldehyde. Specifically, for example: phenol novolac resin, o-cresol novolac resin, p-cresol novolac resin, t-butylphenol novolac resin, dicyclopentadiene cresol resin, poly-p-vinylphenol resin, bisphenol a type novolac resin, or modified products thereof.

The phenolic hydroxyl group contained in these phenolic resins can be easily subjected to an addition reaction with the epoxy group of the epoxy resin by heating, thereby forming a cured product having high impact resistance. Therefore, as the thermosetting component, an epoxy resin and a phenol resin may be used in combination.

The adhesive polymer component can impart a moderate tackiness to the protective layer 100B. The weight average molecular weight (Mw) of the binder polymer is generally in the range of 5 to 200 ten thousand, preferably 10 to 150 ten thousand, and more preferably 20 to 100 ten thousand. When the molecular weight is too low, the film formation of the protective layer 100B becomes insufficient, and when it is too high, the compatibility with other components is deteriorated, and the uniform film formation is prevented. As such binder polymer components, for example: at least one resin selected from the group consisting of acrylic polymers, polyester resins, phenoxy resins, urethane resins, silicone resins, and rubber polymers, and acrylic polymers are particularly preferably used.

Examples of the acrylic polymer include: a (meth) acrylate copolymer formed from constituent units derived from a (meth) acrylate monomer and a (meth) acrylic acid derivative. Among them, as the (meth) acrylate monomer, alkyl (meth) acrylates having an alkyl group of 1 to 18 carbon atoms are preferably used, for example: methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and the like. Examples of the (meth) acrylic acid derivative include: (meth) acrylic acid, glycidyl (meth) acrylate, hydroxyethyl (meth) acrylate, and the like.

When glycidyl groups are introduced into the acrylic polymer using glycidyl methacrylate or the like as a constituent unit, the compatibility with the epoxy resin as the thermosetting component is improved, the glass transition temperature (Tg) of the protective layer 100B after curing is improved, and the heat resistance is improved. In addition, when hydroxyl groups are introduced into the acrylic polymer using hydroxyethyl acrylate or the like as a constituent unit, the adhesion to the object to be processed and the adhesive properties can be controlled.

When an acrylic polymer is used as the binder polymer, the weight average molecular weight (Mw) of the polymer is preferably 10 ten thousand or more, more preferably 15 ten thousand or more and 100 ten thousand or less. The glass transition temperature of the acrylic polymer is usually 20 ℃ or lower, preferably about-70 ℃ to 0 ℃, and the acrylic polymer has adhesiveness at normal temperature (23 ℃).

The blending ratio of the thermosetting component to the binder polymer component is preferably 50 parts by weight or more and 1500 parts by weight or less, more preferably 70 parts by weight or more and 1000 parts by weight or less, and further preferably 80 parts by weight or more and 800 parts by weight or less, with respect to 100 parts by weight of the binder polymer component. When the thermosetting component and the binder polymer are blended in such a ratio, a suitable viscosity is exhibited before curing, a stable pasting work can be performed, and a protective film having excellent film strength can be obtained after curing.

The protective layer 100B preferably contains at least one of a colorant and a filler, and particularly preferably contains both a colorant and a filler.

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 controllability of light transmittance, it is preferable that the colorant contains an organic colorant. The colorant is preferably composed of a pigment from the viewpoint of improving the chemical stability of the colorant (specifically, a small amount of the colorant is not easily eluted, hardly undergoes color migration, and changes with time).

Examples of the filler include: silica such as crystalline silica, fused silica or synthetic silica, and inorganic filler such as alumina or glass beads. Among these inorganic fillers, silica is preferable as the filler, synthetic silica is more preferable, and synthetic silica of a type in which an α -ray source, which is a factor causing malfunction of a semiconductor device, is removed as much as possible is preferable. The shape of the filler may be spherical, needle-like, irregular, etc., and is preferably spherical, more preferably spherical.

In addition, the protective layer 100B may contain a coupling agent. By containing the coupling agent, after the protective layer 100B is cured, the adhesiveness and the close adhesion between the protective film and the object can be improved without impairing the heat resistance of the protective film, and the water resistance (moist heat resistance) can be improved. As the coupling agent, a silane coupling agent is preferable in view of its versatility, cost advantage, and the like.

Examples of the silane coupling agent include: gamma-glycidoxypropyltrimethoxysilane, gamma-glycidoxypropylmethyldiethoxysilane, beta- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, gamma- (methacryloxypropyl) trimethoxysilane, gamma-aminopropyltrimethoxysilane, N-6- (aminoethyl) -gamma-aminopropylmethyldiethoxysilane, N-phenyl-gamma-aminopropyltrimethoxysilane, gamma-ureidopropyltriethoxysilane, gamma-mercaptopropyltrimethoxysilane, gamma-mercaptopropylmethyldimethoxysilane, bis (3-triethoxysilylpropyl) tetrasulfide, N-phenylthiodiglycol, N-glycidoxypropyltrimethoxysilane, gamma-mercaptopropylmethyldimethoxysilane, N-glycidoxypropyltrimethoxysilane, gamma-glycidoxypropyltrimethoxysilane, beta-glycidoxypropyltrimethoxysilane, gamma-glycidoxypropyltrimethoxysilane, beta-glycidoxypropyltrimethoxysilane, gamma-glycidoxypropyltriethoxysilane, gamma-glycidoxypropyl-tert-octadecyloxysilane, beta-glycidoxypropyl-octyltrimethoxysilane, gamma-glycidoxypropyl-tert-octyltrimethoxysilane, gamma-butyltrimethoxysilane, gamma-octyltrimethoxysilane, gamma-butyltrimethoxysilane, gamma-octyltrimethoxysilane, gamma-tert-octyltrimethoxysilane, gamma-butyltrimethoxysilane, gamma-octyltrimethoxysilane, gamma-butyltrimethoxysilane, gamma-octyltrimethoxysilane, gamma-butyltrimethoxysilane, gamma-octyltrimethoxysilane, gamma-butyltrimethoxysilane, gamma-butyl, Methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, imidazolesilane and the like. As the silane coupling agent, one of these silane coupling agents may be used alone, or two or more of these silane coupling agents may be used in combination.

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. In addition, the protective layer 100B may contain an antistatic agent in order to suppress static electricity and improve chip reliability. Further, in order to improve the flame retardant performance of the protective film and improve the reliability as a package, the protective layer 100B may contain a flame retardant such as a phosphoric acid compound, a bromine compound, or a phosphorus compound.

The thickness of the protective layer 100B is not particularly limited. When the protective layer 100B is cured and used 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, in order to effectively exhibit a function as a protective film.

[ Effect of the present embodiment ]

According to the sheet expanding method of the present embodiment, when the 1 st sheet 10 is stretched, the back surface W3 of the semiconductor chip CP and the 1 st adhesive layer 12 of the 1 st sheet 10 are not in contact with each other. Since the protective layer 100B singulated in the dicing step is interposed between the back surface W3 and the 1 st adhesive layer 12, the protective layer 100B in contact with the back surface W3 does not stretch even if the 1 st sheet 10 is stretched. As a result, according to the sheet expanding method of the present embodiment, the adhesive residue can be suppressed.

In the present embodiment, the protective layer 100B has substantially the same shape as the back surface W3 of the semiconductor wafer W, and the protective layer 100B is also singulated from the back surface W3 of the semiconductor chips CP (semiconductor chips on the outer peripheral side) formed on the end portion side of the semiconductor wafer W by dicing, so that the distance between the semiconductor chips CP can be sufficiently increased.

In the present embodiment, the semiconductor wafer W is not supported by a dicing sheet but supported by the composite sheet 140 having the 1 st sheet 10 and the protective layer 100B in the dicing step. Therefore, in order to form a layer (the protective layer 100B in the present embodiment) for protecting the back surface W3 of the semiconductor chip CP after dicing, a step of transferring an adhesive sheet used in the dicing step to another adhesive sheet may not be performed, and the process can be simplified.

Further, before the expanding step is performed, there is no need to transfer the adhesive sheet used in the dicing step to the adhesive sheet used in the expanding step.

Therefore, according to the sheet expanding method of the present embodiment, the process can be simplified as compared with the conventional method, and the space between chips can be sufficiently expanded while suppressing the adhesive residue.

[ variation of embodiment ]

The present invention is not limited to the above embodiments. The present invention includes embodiments obtained by modifying the above-described embodiments, and the like, within a range in which the object of the present invention can be achieved.

For example, the circuit and the like in the semiconductor wafer and the semiconductor chip are not limited to the arrangement, the shape and the like shown in the drawings. The connection structure with the external terminal electrode in the semiconductor package is not limited to the embodiment described in the above embodiment. In the above-described embodiments, the description has been given taking the case of manufacturing FO-WLP type semiconductor packages as an example, but the present invention is also applicable to manufacturing other semiconductor packages such as fan-in type WLP.

The above-described FO-WLP production method may be modified in part of the steps or may be omitted in part of the steps.

The dicing in the dicing step may be performed by irradiating the semiconductor wafer with a laser beam instead of using the cutting mechanism described above. For example, the semiconductor wafer can be completely cut by laser irradiation and singulated into a plurality of semiconductor chips. In these methods, the irradiation of the laser light may be performed from any one side of the semiconductor wafer.

In embodiment 2, the composite sheet 130 is described as having the protective layer 100A and the 3 rd sheet 30, or as having the protective layer 100A as the 3 rd adhesive layer and the 3 rd sheet 30 as the 3 rd substrate, but the present invention is not limited to these forms. For example, a psa sheet having a release layer between the 3 rd psa layer and the 3 rd substrate may be used. The release layer is preferably formed using the same material as the release sheet described in embodiment 1.

Examples

The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples at all.

(preparation of adhesive sheet)

[ example 1]

An acrylic copolymer was obtained by copolymerizing 62 parts by weight of Butyl Acrylate (BA), 10 parts by weight of Methyl Methacrylate (MMA), and 28 parts by weight of 2-hydroxyethyl acrylate (2 HEA). To the acrylic copolymer, 2-isocyanate ethyl methacrylate (product name "Karenz MOI" (registered trademark)) was added to prepare a solution of a resin (acrylic acid a) (a binder base, a solid content 35.0 mass%). The addition rate is as follows: the amount of ethyl 2-isocyanate methacrylate was 90 mol% based on 100 mol% of 2HEA of the acrylic copolymer.

The weight-average molecular weight (Mw) of the resulting resin (acrylic acid A) was 60 ten thousand, and Mw/Mn was 4.5. The weight average molecular weight Mw and the number average molecular weight Mn in terms of standard polystyrene were measured by a Gel Permeation Chromatography (GPC) method, and the molecular weight distribution (Mw/Mn) was determined from each measured value.

To this adhesive base material were added a UV resin a (10-functional urethane acrylate, product name "UV-5806" manufactured by mitsubishi chemical corporation, Mw 1740, and containing a photopolymerization initiator) and a toluene diisocyanate-based crosslinking agent (product name "Coronate L" manufactured by japan polyurethane industries, ltd.) as a crosslinking agent. 50 parts by weight of the UV resin A and 0.2 part by weight of the crosslinking agent were added to 100 parts by weight of the solid content in the binder base material. After the addition, stirring was carried out for 30 minutes, to prepare an adhesive composition A1.

Then, the prepared solution of the pressure-sensitive adhesive composition A1 was applied to a polyethylene terephthalate (PET) release film (product name "SP-PET 381031" manufactured by Lingdeko Co., Ltd., thickness 38 μm) and dried, thereby forming a pressure-sensitive adhesive layer having a thickness of 40 μm on the release film.

A polyester-based urethane elastomer sheet (product name "high dust DUS 202" manufactured by Sheedom corporation, thickness 100 μm) as a substrate was bonded to the pressure-sensitive adhesive layer, and then unnecessary portions of the widthwise ends were cut off to produce a pressure-sensitive adhesive sheet SA 1.

(method of measuring chip spacing)

The pressure-sensitive adhesive sheet obtained in example 1 was cut into pieces of 210mm × 210mm to obtain test pieces. At this time, the cutting is performed such that each side of the cut sheet is parallel or perpendicular to the MD direction of the substrate in the adhesive sheet.

A semiconductor chip to be bonded to the adhesive sheet was prepared in the following order. A sheet (in the examples, sometimes referred to as a protective sheet) as a protective layer was bonded to a 6-inch silicon wafer. As the protective sheet, "E-3125 KL" (product name) manufactured by Lindedoka K.K.K. was used. Next, a 6-inch silicon wafer was cut from the protective sheet side, and a total of 25 chips were cut out so that 3mm × 3 mm-sized chips were 5 rows in the X-axis direction and 5 rows in the Y-axis direction. The cut protective sheet was attached to each chip.

The release film of the test piece was peeled off, and the protective sheet side of the 25 chips cut out as described above was attached to the center portion of the exposed adhesive layer. At this time, the chips are arranged in 5 rows in the X-axis direction and 5 rows in the Y-axis direction.

Next, the test piece with the chip attached thereto was set in a bidirectional stretchable sheet expanding device (detaching device). Fig. 10 shows a top view illustrating the expanding device 400. In fig. 10, the X axis and the Y axis are orthogonal to each other, and the positive direction of the X axis is defined as the + X axis direction, the negative direction of the X axis is defined as the-X axis direction, the positive direction of the Y axis is defined as the + Y axis direction, and the negative direction of the Y axis is defined as the-Y axis direction. The test piece 500 is set in the sheet expanding device 400 so that each side is parallel to the X axis or the Y axis. As a result, the MD direction of the base material in the test piece 500 is parallel to the X axis or the Y axis. In fig. 10, the chip is omitted.

As shown in fig. 10, the sheet expanding device 400 includes 5 holding mechanisms 401 (20 holding mechanisms 401 in total) in the + X-axis direction, the-X-axis direction, the + Y-axis direction, and the-Y-axis direction, respectively. Of the 5 holding mechanisms 401 in each direction, the holding mechanism 401A is located at both ends, the holding mechanism 401C is located at the center, and the holding mechanism 401B is located between the holding

mechanisms

401A and 401C. Each side of the test piece 500 is gripped by the holding means 401.

Here, as shown in FIG. 10, the test piece 500 has a side of 210 mm. The interval between the edge holding mechanisms 401 is 40 mm. The distance between the end portion (the apex of the sheet) on one side of the test sheet 500 and the holding mechanism 401A located on the side and closest to the end portion is 25 mm.

Next, a plurality of tension applying mechanisms, not shown, corresponding to the respective holding mechanisms 401 are driven so that the holding mechanisms 401 move independently from each other. The test piece was fixed at four sides by a holding jig, and the test piece was expanded at a speed of 5mm/s and an expansion amount of 200mm in each of the X-axis direction and the Y-axis direction. Then, the ring frame holds the test piece 500 in the expanded state.

While the chips were kept in the expanded state, the distance between the chips was measured by a digital microscope, and the average value of the distances between the chips was defined as the chip pitch.

When the chip spacing is 1800 μm or more, the chip is judged as pass "A", and when the chip spacing is less than 1800 μm, the chip is judged as fail "B".

(method of measuring chip alignment)

The deviation ratios of the chips adjacent to each other in the X-axis direction and the Y-axis direction with respect to the center line of the workpiece whose chip pitch was measured were measured.

FIG. 11 shows a schematic diagram of a specific measurement method.

A row in which 5 chips were arranged was selected in the X-axis direction, and the distance Dy between the uppermost end of the chip and the lowermost end of the chip in this row was measured using a digital microscope. The deviation ratio in the Y-axis direction was calculated based on the following equation (equation 3). Sy is a chip size in the Y-axis direction, and is set to 3mm in this embodiment.

The deviation rate [% ] in the Y axis direction [ (Dy-Sy)/2 ]/Sy × 100 · (equation 3)

The shift rate in the Y-axis direction was calculated similarly for the other 4 rows in which 5 chips were arranged in the X-axis direction.

A row in which 5 chips were arranged was selected in the Y-axis direction, and the distance Dx between the leftmost end of the chip and the rightmost end of the chip in the row was measured by a digital microscope. The deviation ratio in the X-axis direction was calculated based on the following equation (equation 4). Sx is the chip size in the X-axis direction, and is set to 3mm in this embodiment.

The deviation rate [% ] [ (Dx-Sx)/2 ]/sxx × 100 · (equation 4)

The deviation ratio in the X-axis direction was calculated similarly for the other 4 rows in which 5 chips were arranged in the Y-axis direction.

In equations (equation 3) and (equation 4), division by 2 is performed to represent, in absolute terms, the maximum distance that the expanded chip is displaced from a given position.

The case where the deviation ratio is less than ± 10% in all the rows (10 rows in total) in the X-axis direction and the Y-axis direction is determined as pass "a", and the case where the deviation ratio is ± 10% or more in 1 or more rows is determined as fail "B".

(method of evaluating cull)

After the sheet was spread under the conditions described in the method for measuring the chip spacing, the surface of the adhesive sheet of example 1 opposite to the surface on which the chip was mounted was irradiated with an ultraviolet ray at an illuminance of 220mW/cm using an ultraviolet irradiation apparatus ("RAD-2000 m/12", manufactured by Linekec corporation)²Light quantity 460mJ/cm²The conditions of (4) were ultraviolet irradiation. After the ultraviolet irradiation, the chip was held on the adhesive tape, and the adhesive sheet was peeled off. After the adhesive sheet was peeled off, the surface of the chip to which the adhesive sheet was attached was observed with an optical microscope. The chip was judged as "acceptable" A "when no adhesive residue was observed on the chip surface, and judged as" unacceptable "B" when no adhesive residue was observed.

When the pressure-sensitive adhesive sheet of example 1 was used for expansion, the evaluation result of the chip spacing was judged as "a" pass, and the evaluation result of the chip alignment was judged as "a" pass.

When the adhesive sheet was expanded with the protective sheet interposed between the chip and the adhesive sheet of the example, the evaluation result of the residual adhesive on the chip surface was judged as pass "a".

Claims

1. A method of expanding a wafer, the method comprising:

a step of stretching the 1 st sheet to which the plurality of semiconductor devices are bonded to expand the intervals between the plurality of semiconductor devices,

the plurality of semiconductor devices each having a1 st semiconductor device surface and a 2 nd semiconductor device surface on the opposite side of the 1 st semiconductor device surface,

the plurality of semiconductor devices are bonded to the 1 st semiconductor device surface or the 2 nd semiconductor device surface with a protective layer interposed therebetween.

2. The method for expanding slice as claimed in claim 1,

after the protective layer is formed on the 1 st semiconductor device surface, the plurality of semiconductor devices are bonded to the 1 st sheet.

3. The film expanding method according to claim 1 or 2,

the object is cut to obtain the plurality of semiconductor devices.

4. The film expanding method according to claim 3,

forming the protective layer on the object to be processed,

and dicing the object and the protective layer to obtain the plurality of semiconductor devices.

5. The film expanding method according to claim 4,

bonding the object to be processed on which the protective layer is formed to the 2 nd adhesive layer of a 2 nd adhesive sheet having a 2 nd adhesive layer and a 2 nd substrate,

dicing the protective layer and the object to be processed to obtain the plurality of semiconductor devices,

and attaching the 1 st sheet to the cut protective layer.

6. The film expanding method according to claim 5,

after the 1 st sheet is bonded to the cut protective layer, the 2 nd adhesive sheet is peeled off.

7. The method for expanding slice as claimed in claim 3 or 4,

bonding the object to the protective layer of the composite sheet having the protective layer and the 3 rd sheet,

dicing the object and the protective layer to obtain the plurality of semiconductor devices,

peeling the 3 rd sheet from the protective layer.

8. The film expanding method according to claim 3,

the protective layer and the 1 st sheet are laminated together in advance,

the object to be processed is supported by the protective layer,

9. A method for expanding sheet according to any one of claims 3 to 8, wherein,

the object to be processed is a semiconductor wafer.

10. The sheet expanding method according to any one of claims 1 to 9,

the No. 1 sheet is an expansion sheet.

11. The sheet expanding method according to any one of claims 1 to 10,

the 1 st semiconductor device surface has a circuit.

12. A method for manufacturing a semiconductor device, comprising the method for expanding a wafer as defined in any one of claims 1 to 11.