JPWO2020158770A1 - Expanding method and manufacturing method of semiconductor devices - Google Patents

Abstract

A first adhesive sheet (10) having a first adhesive layer (12) and a first base material (11) is attached to a second wafer surface of a wafer having a first wafer surface and a second wafer surface. The tensile elongation of the first base material (11) with a notch of 50 μm in depth is 300% or more, and the notch is made from the surface side of the first wafer to separate the wafer into a plurality of chips (CP). Further, an expanding method in which the first pressure-sensitive adhesive layer (12) of the first pressure-sensitive adhesive sheet (10) is cut and the first pressure-sensitive adhesive sheet (10) is stretched to widen the interval (CP) between a plurality of chips.

Description

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

In recent years, electronic devices have become smaller, lighter, and more sophisticated. Semiconductor devices mounted on electronic devices are also required to be smaller, thinner, and higher in density. Semiconductor chips may be mounted in packages close to their size. Such a package is sometimes referred to as a chip scale package (CSP). One of the CSPs is a wafer level package (WLP). In WLP, an external electrode or the like is formed on the wafer before it is individualized by dicing, and finally the wafer is diced and individualized. Examples of WLP include a fan-in type and a fan-out type. In a fan-out type WLP (hereinafter, may be abbreviated as "FO-WLP"), the semiconductor chip is covered with a sealing member so as to have a region larger than the chip size, and the semiconductor chip encapsulant is covered. It is formed, and the rewiring layer and the external electrode are formed not only on the circuit surface of the semiconductor chip but also on the surface region of the sealing member.

For example, in Patent Document 1, an expansion wafer is formed by surrounding a plurality of semiconductor chips separated from a semiconductor wafer by using a mold member, leaving a circuit forming surface thereof, and forming an expansion wafer in a region outside the semiconductor chip. A method for manufacturing a semiconductor package formed by extending a rewiring pattern is described. In the manufacturing method described in Patent Document 1, before enclosing a plurality of fragmented semiconductor chips with a mold member, they are replaced with a wafer mount tape for expansion, and the wafer mount tape is spread to form a plurality of semiconductor chips. The distance between them is increasing.

Further, Patent Document 2 includes a second base material layer, a first base material layer, and a first pressure-sensitive adhesive layer in this order, and the second base material layer has a breaking elongation of 400% or more. The sheet is listed. The method for manufacturing a semiconductor device described in Patent Document 2 includes a step of attaching a semiconductor wafer to the first pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet and a step of separating the semiconductor wafer by dicing to form a plurality of semiconductor chips. , The step of stretching the adhesive sheet to widen the distance between the semiconductor chips is provided.

International Publication No. 2010/0864646 Japanese Unexamined Patent Publication No. 2017-07648

In the manufacturing method described in Patent Document 1, the tape used for individualizing the semiconductor wafer and the tape used for expanding the tape in order to increase the distance between the semiconductor chips are different, so that the tape is attached. Need to change.
In the method for manufacturing a semiconductor device described in Patent Document 2, the pressure-sensitive adhesive sheet used for individualizing a semiconductor wafer and the pressure-sensitive adhesive sheet used for increasing the distance between semiconductor chips are the same. However, since the pressure-sensitive adhesive sheet used in Patent Document 2 has a sheet structure in which a second base material layer, a first base material layer, and a first pressure-sensitive adhesive layer are laminated, dicing and dicing with a simpler tape structure and There is a demand for expandable methods. Further, in the process described in Patent Document 2, it is necessary to carefully control the cutting depth of the dicing blade so that the dicing blade does not reach the second base material layer during dicing. Therefore, there is also a demand for a simpler expanding method.

An object of the present invention is to provide an expanding method in which a tape structure and a process are simplified as compared with the conventional case, and to provide a method for manufacturing a semiconductor device including the expanding method.

According to one aspect of the present invention, a first pressure-sensitive adhesive layer and a first base material are formed on the second wafer surface of a wafer having a first wafer surface and a second wafer surface opposite to the first wafer surface. The first adhesive sheet having the above is attached, and the tensile elongation of the first substrate having a notch of 50 μm in depth is 300% or more, and the notch is made from the surface side of the first wafer to make the wafer. Provided is an expanding method in which the first pressure-sensitive adhesive layer of the first pressure-sensitive adhesive sheet is cut into pieces, the first pressure-sensitive adhesive sheet is stretched, and the distance between the plurality of chips is widened. ..

In the expanding method according to one aspect of the present invention, it is preferable that the cut is formed at a depth from the first wafer surface side to reach the first substrate.

In the expanding method according to one aspect of the present invention, the thickness of the first base material is T1, and the depth of cut T2 made in the first base material is 0.2 × T1 or less. preferable.

In the expanding method according to one aspect of the present invention, the first substrate preferably contains a thermoplastic elastomer.

In the expanding method according to one aspect of the present invention, the first base material preferably contains a urethane-based elastomer.

In the expanding method according to one aspect of the present invention, the first pressure-sensitive adhesive layer preferably contains an energy ray-curable resin.

In the expanding method according to one aspect of the present invention, the first pressure-sensitive adhesive sheet is stretched to widen the space between the plurality of chips, and then the first pressure-sensitive adhesive layer is irradiated with energy rays to obtain the first pressure-sensitive adhesive. It is preferable to cure the layer.

In the expanding method according to one aspect of the present invention, the first pressure-sensitive adhesive sheet is preferably an expanding sheet.

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

In the expanding method according to one aspect of the present invention, it is preferable that the first wafer surface has a circuit.

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

According to one aspect of the present invention, it is possible to provide an expanding method in which the tape structure and the process are simplified as compared with the conventional case. According to another aspect of the present invention, it is possible to provide a method for manufacturing a semiconductor device including the expanding method.

It is sectional drawing explaining the manufacturing method which concerns on 1st Embodiment. It is sectional drawing explaining the manufacturing method which concerns on 1st Embodiment. It is a partially enlarged sectional view explaining the manufacturing method which concerns on 1st Embodiment. It is sectional drawing explaining the manufacturing method which concerns on 1st Embodiment. It is sectional drawing explaining the manufacturing method which concerns on 1st Embodiment. It is sectional drawing explaining the manufacturing method which concerns on 1st Embodiment. It is sectional drawing explaining the manufacturing method which concerns on 1st Embodiment. It is a top view explaining the biaxial stretching expansion apparatus used in an Example. It is a schematic diagram for demonstrating the measuring method of chip alignment.

[First Embodiment]
Hereinafter, the expanding method according to the present embodiment and the manufacturing method of the semiconductor device including the expanding method will be described.

1 (FIG. 1A and 1B), FIG. 2, FIG. 3 (FIGS. 3A and 3B) and FIG. 4 (FIGS. 4A and 4B) describe a method for manufacturing a semiconductor device including an expanding method according to the present embodiment. It is a cross-sectional schematic diagram.

The expanding method according to the present embodiment includes the following steps (P1) to (P3). (P1) A step of attaching a first adhesive sheet to a second wafer surface of a wafer having a first wafer surface and a second wafer surface. The first pressure-sensitive adhesive sheet has a first pressure-sensitive adhesive layer and a first base material.
(P2) A step of making a notch from the surface side of the first wafer, cutting the wafer and the first pressure-sensitive adhesive layer, and separating them into a plurality of chips. The first wafer surface is the circuit surface of the chip, and the second wafer surface is the back surface of the chip. Make a notch up to the first adhesive layer. If the notch has a predetermined depth, it may reach the first base material.
(P3) A step of stretching the first adhesive sheet to widen the space between a plurality of chips.

FIG. 1A is a diagram for explaining the process (P1). FIG. 1A shows a wafer W to which the first adhesive sheet 10 is attached.
The semiconductor wafer W has a circuit surface W1 as a first wafer surface and a back surface W3 as a second wafer surface. A circuit W2 is formed on the circuit surface W1.

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

The semiconductor wafer W is held on the first adhesive sheet 10. In the present embodiment, an embodiment in which the process proceeds with the circuit surface W1 exposed will be described as an example, but as another example, for example, a protective member such as a protective sheet or a protective film is provided on the circuit surface W1. An embodiment in which the process proceeds in the attached state can be mentioned.
The first pressure-sensitive adhesive sheet 10 has a first pressure-sensitive adhesive layer 12 and a first base material 11.
The first base material 11 according to the present embodiment is 300% or more when the tensile elongation is measured by making a notch of a predetermined depth. Specifically, it is preferable that the tensile elongation of the first base material 11 having a notch having a depth of 50 μm is 300% or more. If the tensile elongation is 300% or more, even if a notch having a depth of 50 μm is made in the first base material 11 in the dicing step, the first adhesive sheet 10 is expanded as it is without being replaced with another adhesive sheet. , The distance between the semiconductor chip CPs can be expanded without breaking the first adhesive sheet. The tensile elongation of the first base material 11 with a notch having a depth of 50 μm is preferably 3000% or less.
For example, when a notch having a depth of 50 μm is formed in the first base material having a thickness of 60 μm, that is, about 83% (50 μm / 60 μm ≈ 0) with respect to the thickness of the first base material 11 of 60 μm. Even when a notch with a depth of .83) is formed, if the first base material 11 has the tensile elongation as described above, the first adhesive sheet does not break even if it is expanded. .. The depth of cut is preferably 85% or less, more preferably 70% or less, and even more preferably 60% or less with respect to the thickness of the first base material 11.

(Measurement method of tensile elongation)
The substrate is cut into a size of 15 mm × 140 mm to obtain a test piece. For this test piece, the tensile elongation at 23 ° C. is measured according to JIS K6732: 2006. Specifically, the above test piece is set to a chuck distance of 100 mm with a tensile tester (manufactured by Shimadzu Corporation, product name "Autograph AG-IS 500N"), and then a tensile test is performed at a speed of 200 mm / min. And measure the elongation (%).

The first base material 11 has a first base material surface 11a and a first base material back surface 11b on the opposite side of the first base material surface 11a (see FIG. 2). The first pressure-sensitive adhesive layer 12 is laminated on the surface 11a of the first base material.
Other details regarding the first adhesive sheet 10 will be described later.

[Backgrinding process]
The semiconductor wafer W prepared in the step (P1) is preferably a wafer obtained by undergoing a backgrinding step.
In the backgrinding step, the surface of the semiconductor wafer W opposite to the circuit surface W1 is ground until the wafer has 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 the semiconductor wafer W is referred to as the 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 grinding the semiconductor wafer W, it is preferable to attach an adhesive sheet called a back grind sheet to the circuit surface W1 in order to protect the circuit W2. In the back surface grinding of the wafer, the circuit surface W1 side of the semiconductor wafer W, that is, the back grind sheet side is fixed by a chuck table or the like, and the back surface side on which the circuit is not formed is ground by a grinder.

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

[Attachment process of the first adhesive sheet]
The semiconductor wafer W prepared in the step (P1) is preferably a wafer obtained through a back grind step and further a sticking step of sticking the first adhesive sheet 10 to the back surface W3. This sticking step may be referred to as a sticking step of the first adhesive sheet.
As will be described later, in the step (P2), the semiconductor wafer W is separated into a plurality of semiconductor chip CPs by dicing, and in the step (P3), the distance between the plurality of semiconductor chip CPs is expanded by the expansion. .. In the present embodiment, the first adhesive sheet 10 is attached to the back surface W3 in order to hold the semiconductor wafer W when dicing the semiconductor wafer W and to hold the semiconductor chip CP when expanding the adhesive sheet. do.

[Dicing process]
FIG. 1B is a diagram for explaining the step (P2). The process (P2) may be referred to as a dicing process. FIG. 1B shows a plurality of semiconductor chip CPs held on the first adhesive sheet 10. For dicing, a cutting means such as a dicing saw is used.
The semiconductor wafer W in a state where the first adhesive sheet 10 is attached to the back surface W3 is separated into pieces by dicing to form a plurality of semiconductor chip CPs. The circuit surface W1 as the first wafer surface corresponds to the circuit surface of the chip. The back surface W3 as the second wafer surface corresponds to the back surface of the chip.

In the present embodiment, a notch is made from the circuit surface W1 side to cut the semiconductor wafer W, and further cut the first pressure-sensitive adhesive layer 12. The cutting depth during dicing is not particularly limited as long as the semiconductor wafer W and the first pressure-sensitive adhesive layer 12 can be separated into individual pieces. In the present embodiment, from the viewpoint of more reliably cutting the semiconductor wafer W and the first pressure-sensitive adhesive layer 12, an embodiment in which a cut is made up to the first base material 11 as shown in FIG. 1B will be described as an example. The present invention is not limited to such an aspect. For example, in another embodiment, it is also preferable to cut the first pressure-sensitive adhesive layer 12 while preventing the notch from reaching the first base material 11 by dicing.

FIG. 2 shows a schematic cross-sectional view showing a partially enlarged portion of a portion where the semiconductor wafer W and the first pressure-sensitive adhesive layer 12 are cut in the dicing step.
In the present embodiment, a notch having a predetermined depth is made in the first base material 11. As shown in FIG. 2, of the depths of cuts made in the dicing step, the depth of cut T2 from the surface 11a of the first base material 11 of the first base material 11 is used. The thickness of the first base material 11 is T1. In this case, it is preferable that the thickness T1 and the cutting depth T2 satisfy the following relationship (Equation 1). The unit of T1 and T2 is μm (micrometer).
T2 ≤ 0.2 × T1 ... (Equation 1)

In the present embodiment, a laminated structure in which the individualized first pressure-sensitive adhesive layer 12 is interposed between the plurality of semiconductor chip CPs and the first base material 11 is formed on the back surface W3 side of the semiconductor chip CP by the dicing step. can get.

[Expanding process]
FIG. 3A is a diagram for explaining the process (P3). The step (P3) may be referred to as an expanding step. FIG. 3A shows a state in which the first pressure-sensitive adhesive sheet 10 is stretched after the dicing step to widen the distance between the plurality of semiconductor chip CPs.
When expanding the distance between the plurality of semiconductor chip CPs, it is preferable to extend the expanded sheet while holding the plurality of semiconductor chip CPs by an adhesive sheet called an expand sheet. In the present embodiment, it is preferable that the first adhesive sheet 10 is an expanded sheet.

In the expanding step according to the present embodiment, the first pressure-sensitive adhesive sheet 10 used in the dicing step is used as it is. In the dicing step of the present embodiment, the first base material 11 has a notch of a predetermined depth, but the first base material has a tensile elongation of the first base material 11 having a notch of 50 μm in depth. Since it is 300% or more, the first base material 11 does not break even if the expanding step is carried out.

The method of stretching the first adhesive sheet 10 in the expanding step is not particularly limited. As a method of stretching the first adhesive sheet 10, for example, a method of pressing an annular or circular expander to stretch the first adhesive sheet 10, and a method of grasping the outer peripheral portion of the first adhesive sheet 10 by using a gripping member or the like. The method of stretching with is mentioned. In the present embodiment, the interval D1 between the plurality of semiconductor chip CPs is not particularly limited because it depends on the size of the semiconductor chip CPs. In particular, in a plurality of semiconductor chip CPs attached to one side of the pressure-sensitive adhesive sheet, the distance D1 between adjacent semiconductor chip CPs is preferably 200 μm or more. The upper limit of the mutual spacing between the semiconductor chip CPs is not particularly limited. The upper limit of the mutual spacing between the semiconductor chip CPs may be, for example, 6000 μm.

[Energy ray irradiation process]
After stretching the first pressure-sensitive adhesive sheet 10 to widen the interval between the plurality of semiconductor chip CPs, it is possible to carry out a step of irradiating the first pressure-sensitive adhesive layer 12 with energy rays to cure the first pressure-sensitive adhesive layer 12. preferable. This process may be referred to as an "energy ray irradiation process".
The energy ray to irradiate the first pressure-sensitive adhesive layer 12 is appropriately selected according to the type of the energy ray-curable resin contained in the first pressure-sensitive adhesive layer 12. When the first pressure-sensitive adhesive layer 12 contains an ultraviolet curable resin and has ultraviolet curability, the first adhesive sheet 10 is irradiated with ultraviolet rays in the energy ray irradiation step. By curing the first pressure-sensitive adhesive layer 12 after the expanding step, the shape retention of the first pressure-sensitive adhesive sheet 10 after stretching is improved. As a result, the alignment of the plurality of semiconductor chip CPs attached to the first pressure-sensitive adhesive layer 12 can be easily maintained.
It is preferable that the timing of carrying out the energy ray irradiation step is after the expanding step and before the peeling step of the first pressure-sensitive adhesive sheet, which will be described later. From the viewpoint of easily maintaining the alignment of the plurality of semiconductor chip CPs, it is preferable that the energy ray irradiation step is performed after the expanding step and before the first transfer step.

[First transfer step]
In the present embodiment, after the expanding step, a plurality of semiconductor chip CPs attached to the first pressure-sensitive adhesive sheet 10 are transferred to another pressure-sensitive adhesive sheet (for example, a second pressure-sensitive adhesive sheet) (hereinafter, "first". It may be referred to as "transfer step").
FIG. 3B is a diagram illustrating a step of transferring a plurality of semiconductor chip CPs attached to the first adhesive sheet 10 to the second adhesive sheet 20 (sometimes referred to as a “first transfer step”). It is shown.
The second adhesive sheet 20 is not particularly limited as long as it can hold a plurality of semiconductor chip CPs. The second pressure-sensitive adhesive sheet 20 has a second base material 21 and a second pressure-sensitive adhesive layer 22. When it is desired to seal a plurality of semiconductor chip CPs on the second pressure-sensitive adhesive sheet 20, it is preferable to use a pressure-sensitive adhesive sheet for the sealing process as the second pressure-sensitive adhesive sheet 20, and it is preferable to use a heat-resistant pressure-sensitive adhesive sheet. More preferred. When a heat-resistant pressure-sensitive adhesive sheet is used as the second pressure-sensitive adhesive sheet 20, the second base material 21 and the second pressure-sensitive adhesive layer 22 each have heat resistance that can withstand the temperature imposed in the sealing step. It is preferably made of a material.

When the transfer step is carried out in the present embodiment, for example, after the expanding step, the second adhesive sheet 20 is attached to the circuit surface W1 of the plurality of semiconductor chip CPs, and then the first adhesive sheet 10 is attached from the back surface W3. It is preferable to peel off.

[Peeling process of the first adhesive sheet]
FIG. 4A is a diagram illustrating a step of peeling the first pressure-sensitive adhesive sheet 10 from the back surface W3, and this step may be referred to as a step of peeling off the first pressure-sensitive adhesive sheet.
Even after the peeling step of the first pressure-sensitive adhesive sheet, it is preferable that the distance D1 between the plurality of semiconductor chip CPs expanded in the expanding step is maintained.

The first pressure-sensitive adhesive layer 12 of the first pressure-sensitive adhesive sheet 10 contains an energy ray-curable resin from one viewpoint of suppressing adhesive residue on the back surface W3 when the first pressure-sensitive adhesive sheet 10 is peeled off from the back surface W3. It is preferable to do so. When the first pressure-sensitive adhesive layer 12 contains an energy ray-curable resin, the first pressure-sensitive adhesive sheet 10 is irradiated with energy rays to cure the energy ray-curable resin. When the energy ray-curable resin is cured, the cohesive force of the adhesive component in the first adhesive layer 12 is increased, and the adhesive force between the first adhesive layer 12 and the back surface W3 of the semiconductor chip CP is reduced or eliminated. be able to. Examples of the energy ray include ultraviolet rays (UV) and electron beams (EB), and ultraviolet rays are preferable. Therefore, the energy ray curable resin is preferably an ultraviolet curable resin. The first base material 11 preferably has the permeability of energy rays.

The second adhesive sheet 20 may be attached to the ring frame together with the plurality of semiconductor chip CPs. In this case, a ring frame is placed on the second adhesive layer 22 of the second adhesive sheet 20 and lightly pressed to fix it. After that, the second pressure-sensitive adhesive layer 22 exposed inside the ring shape of the ring frame is pressed against the circuit surface W1 of the semiconductor chip CP, and the plurality of semiconductor chip CPs are fixed to the second pressure-sensitive adhesive sheet 20.

[Sealing process]
FIG. 4B shows a diagram illustrating a step of sealing a plurality of semiconductor chip CPs using the sealing member 300 (hereinafter, may be referred to as a “sealing step”).

In the present embodiment, the sealing step is performed after the plurality of semiconductor chip CPs are transferred to the second pressure-sensitive adhesive sheet 20.
In the sealing step, the sealing body 3 is formed by covering a plurality of semiconductor chip CPs with the sealing member 300 while the circuit surface W1 is protected by the second adhesive sheet 20. The sealing member 300 is also filled between the plurality of semiconductor chip CPs. Since the circuit surface W1 and the circuit W2 are covered by the second adhesive sheet 20, it is possible to prevent the circuit surface W1 from being covered by the sealing member 300.

By the sealing step, a sealing body 3 in which a plurality of semiconductor chip CPs separated by a predetermined distance are embedded in the sealing member 300 can be obtained. In the sealing step, it is preferable that the plurality of semiconductor chip CPs are covered with the sealing member 300 while the interval D1 after the expanding step is maintained.

After the sealing step, the second adhesive sheet 20 is peeled off. When the second adhesive sheet 20 is peeled off, the circuit surface W1 of the semiconductor chip CP and the surface 3A in contact with the second adhesive sheet 20 of the sealing body 3 are exposed.

By repeating the transfer step and the expanding step an arbitrary number of times after the above-mentioned expanding step, the distance between the semiconductor chip CPs is set to the desired distance, and the orientation of the circuit surface when sealing the semiconductor chip CP is set to the desired orientation. can do.

[Other processes]
A rewiring layer forming step of forming a rewiring layer electrically connected to the semiconductor chip CP with respect to the sealing body 3 after peeling the adhesive sheet from the sealing body 3, and a rewiring layer and an external terminal electrode. The connection process of electrically connecting the and is performed in order. The circuit of the semiconductor chip CP and the external terminal electrode are electrically connected by the rewiring layer forming step and the connection step with the external terminal electrode.
The encapsulant 3 to which the external terminal electrode is connected is individualized in units of semiconductor chip CP. The method for individualizing the sealing body 3 is not particularly limited. By individualizing the encapsulant 3, a semiconductor package of semiconductor chip CP units is manufactured. A semiconductor package in which a fan-out external electrode is connected outside the region of the semiconductor chip CP is manufactured as a fan-out type wafer level package (FO-WLP).

(1st adhesive sheet)
The first pressure-sensitive adhesive sheet 10 has a first base material 11 and a first pressure-sensitive adhesive layer 12. The first pressure-sensitive adhesive layer 12 is laminated on the first base material 11.

1. First base material The constituent material of the first base material 11 is not particularly limited as long as it can function appropriately in a desired step (for example, steps (P1) to (P3)) such as an expanding step.
The first base material 11 has a first base material surface 11a and a first base material back surface 11b. The back surface 11b of the first base material is a surface opposite to the surface surface 11a of the first base material.
In the first pressure-sensitive adhesive sheet 10, it is preferable that the first pressure-sensitive adhesive layer 12 is provided on one surface of the front surface 11a of the first base material and the back surface 11b of the first base material, and the pressure-sensitive adhesive layer is provided on the other surface. It is preferable that it is not. In the present embodiment, the first pressure-sensitive adhesive layer 12 is provided on the surface 11a of the first base material.

The material of the first base material 11 is preferably a thermoplastic elastomer or a rubber-based material, and more preferably a thermoplastic elastomer, from the viewpoint of being large and easy to stretch.

Further, as the material of the first base material 11, it is preferable to use a resin having a relatively low glass transition temperature (Tg) from the viewpoint of being large and easy to stretch. The glass transition temperature (Tg) of such a resin is preferably 90 ° C. or lower, more preferably 80 ° C. or lower, and even more preferably 70 ° C. or lower.

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

Urethane-based elastomers are generally obtained by reacting a long-chain polyol, a chain extender, and a diisocyanate. The urethane-based elastomer comprises 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.

When urethane-based elastomers are classified according to the type of long-chain polyol, they are classified into polyester-based polyurethane elastomers, polyether-based polyurethane elastomers, polycarbonate-based polyurethane elastomers, and the like. Urethane-based elastomers can be used alone or in combination of two or more. In the present embodiment, the urethane-based elastomer is preferably a polyether-based polyurethane elastomer from the viewpoint of being large and easy to stretch.

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

Examples of the diisocyanate include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate and the like. In the present embodiment, the diisocyanate is preferably hexamethylene diisocyanate from the viewpoint of being large and easy to stretch.

Examples of the chain extender include low molecular weight polyhydric alcohols (eg, 1,4-butanediol, 1,6-hexanediol, etc.), aromatic diamines, and the like. Of these, 1,6-hexanediol is preferably used from the viewpoint of being easy to stretch significantly.

Examples of the olefin-based elastomer include ethylene / α-olefin copolymer, propylene / α-olefin copolymer, butene / α-olefin copolymer, ethylene / propylene / α-olefin copolymer, and ethylene / butene / α-. Selected from the group consisting of olefin copolymers, propylene / butene-α-olefin copolymers, ethylene / propylene / butene-α / olefin copolymers, styrene / isoprene copolymers, and styrene / ethylene / butylene copolymers. Examples include polymers containing at least one resin. The olefin-based elastomer may be used alone or in combination of two or more.

The density of the olefin-based elastomer is not particularly limited. For example, the density of the olefin elastomers, 0.860 g / cm ³ or more is preferably less than ^{0.905g / cm 3, 0.862g / cm} 3 or more, more is less than 0.900 g / cm ³ It is preferably 0.864 ^{g / cm 3} or more and less than 0.895 g / cm ^3. When the density of the olefin-based elastomer satisfies the above range, the base material is excellent in unevenness followability when a semiconductor device such as a semiconductor wafer as an adherend is attached to the pressure-sensitive adhesive sheet.

The olefin-based elastomer has a mass ratio of a monomer composed of an olefin-based compound (also referred to as “olefin content” in the present specification) of 50% by mass among all the monomers used for forming the elastomer. As mentioned above, it is preferably 100% by mass or less.
When the olefin content is excessively low, the properties of the elastomer containing the structural unit derived from the olefin are less likely to appear, and the base material is less likely to exhibit flexibility and rubber elasticity.
From the viewpoint of stably obtaining flexibility and rubber elasticity, the olefin content is preferably 50% by mass or more, and more preferably 60% by mass or more.

Examples of the styrene-based elastomer include a styrene-conjugated diene copolymer and a styrene-olefin copolymer. Specific examples of the styrene-conjugated diene copolymer include a styrene-butadiene copolymer, a styrene-butadiene-styrene copolymer (SBS), a styrene-butadiene-butylene-styrene copolymer, and a styrene-isoprene copolymer. Unhydrogenated styrene-conjugated diene copolymers such as styrene-isoprene-styrene copolymer (SIS), styrene-ethylene-isoprene-styrene copolymers, styrene-ethylene / propylene-styrene copolymers (SEPS, styrene- Hydroadditives of isoprene-styrene copolymer) and hydrogenated styrene-conjugated diene copolymers such as styrene-ethylene-butylene-styrene copolymers (SEBS, hydrogenated additives of styrene-butadiene copolymers). Can be mentioned. Industrially, as styrene-based elastomers, Toughprene (manufactured by Asahi Kasei Corporation), Clayton (manufactured by Clayton Polymer Japan Co., Ltd.), Sumitomo TPE-SB (manufactured by Sumitomo Chemical Co., Ltd.), Epofriend (manufactured by Daicel Co., Ltd.) ), Lavalon (manufactured by Mitsubishi Chemical Co., Ltd.), Septon (manufactured by Kuraray Co., Ltd.), and Tough Tech (manufactured by Asahi Kasei Corporation). The styrene-based elastomer may be hydrogenated or unhydrogenated.

Examples of the rubber-based material include natural rubber, synthetic isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), chloroprene rubber (CR), acrylonitrile-butadiene copolymer rubber (NBR), and butyl rubber (NBR). IIR), halogenated butyl rubber, acrylic rubber, urethane rubber, polysulfide rubber and the like can be mentioned. As the rubber-based material, one of these can be used alone or in combination of two or more.

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

The first base material 11 may contain an additive in a film containing the above resin-based material as a main material. Examples of the additive include pigments, dyes, flame retardants, plasticizers, antistatic agents, lubricants, fillers and the like. Examples of the pigment 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 metallic materials such as nickel particles. The content of the additive that may be contained in the film is not particularly limited, but is preferably limited to a range in which the first base material 11 can exhibit a desired function.

The first base material 11 is treated on one or both sides of the first base material 11 to improve the adhesion to the first pressure-sensitive adhesive layer 12 laminated on the surface of the first base material 11. May be good.

When the first pressure-sensitive adhesive layer 12 contains an energy ray-curable pressure-sensitive adhesive, the first base material 11 preferably has permeability to energy rays. When ultraviolet rays are used as energy rays, it is preferable that the first base material 11 has transparency to ultraviolet rays. When an electron beam is used as the energy ray, it is preferable that the first base material 11 has the transparency of the electron beam.

The thickness of the first substrate 11 is not limited as long as the first pressure-sensitive adhesive sheet 10 can function properly in the desired process. The thickness of the first base material 11 is preferably 60 μm or more, more preferably 80 μm or more. The thickness of the first base material 11 is preferably 250 μm or less, more preferably 200 μm or less.

Further, the standard thickness of the first base material 11 when the thickness of the first base material 11 is measured at a plurality of locations in the in-plane direction of the first base material surface 11a or the back surface 11b of the first base material 11 at intervals of 2 cm. The deviation is preferably 2 μm or less, more preferably 1.5 μm or less, and even more preferably 1 μm or less. When the standard deviation is 2 μm or less, the first pressure-sensitive adhesive sheet 10 has a highly accurate thickness, and the first pressure-sensitive adhesive sheet 10 can be uniformly stretched.

At 23 ° C, the tensile elastic modulus of the first base material 11 in the MD direction and the CD direction is 10 MPa or more and 350 MPa or less, respectively, and at 23 ° C., the 100% stress of the first base material 11 in the MD direction and the CD direction is, respectively. It is preferably 3 MPa or more and 20 MPa or less.
When the tensile elastic modulus and 100% stress are in the above ranges, the first pressure-sensitive adhesive sheet 10 can be greatly stretched.
The 100% stress of the first base material 11 is a value obtained as follows. A test piece having a size of 150 mm (length direction) × 15 mm (width direction) is cut out from the first base material 11. Grasp both ends of the cut out test piece in the length direction with a gripping tool so that the length between the gripping tools is 100 mm. After grasping the test piece with the gripping tool, the test piece is pulled in the length direction at a speed of 200 mm / min, and the measured value of the tensile force when the length between the gripping tools becomes 200 mm is read. The 100% stress of the first base material 11 is a value obtained by dividing the read measured value of the tensile force by the cross-sectional area of the base material. The cross-sectional area of the first base material 11 is calculated by the length in the width direction of 15 mm × the thickness of the first base material 11 (test piece). The cutting is performed so that the flow direction (MD direction) or the direction orthogonal to the MD direction (CD direction) at the time of manufacturing the base material and the length direction of the test piece coincide with each other. In this tensile test, the thickness of the test piece is not particularly limited and may be the same as the thickness of the base material to be tested.

It is preferable that the breaking elongation of the first base material 11 in the MD direction and the CD direction at 23 ° C. is 100% or more, respectively.
When the breaking elongation of the first base material 11 in the MD direction and the breaking elongation in the CD direction is 100% or more, the first pressure-sensitive adhesive sheet 10 can be greatly stretched without breaking.

The tensile elastic modulus (MPa) of the base material and the breaking elongation (%) of the base material can be measured as follows. The substrate is cut into 15 mm × 140 mm to obtain a test piece. For the test piece, the elongation at break and the tensile modulus at 23 ° C. are measured according to JIS K7161: 2014 and JIS K7127: 1999. Specifically, the above test piece is pulled at a speed of 200 mm / min after setting the distance between chucks to 100 mm with a tensile tester (manufactured by Shimadzu Corporation, product name "Autograph AG-IS 500N"). Perform a test and measure the elongation at break (%) and tensile modulus (MPa). The measurement is performed in both the flow direction (MD) at the time of manufacturing the base material and the direction perpendicular to the flow direction (CD).

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

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

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 that polymerizes and cures when irradiated with energy rays. Examples of the energy ray include ultraviolet rays and electron beams.
Examples of the energy ray-curable resin (ax1) include low molecular weight compounds having an energy ray-polymerizable group (monofunctional monomer, polyfunctional monomer, monofunctional oligomer, and polyfunctional oligomer). Specific examples of the energy ray-curable resin (ax1) include trimethyl propantriacrylate, tetramethylolmethanetetraacrylate, pentaerythritol triacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, 1,4-. Butylene glycol diacrylate and acrylates such as 1,6-hexanediol diacrylate, dicyclopentadiene dimethoxydiacrylate, cyclic aliphatic skeleton-containing acrylates such as isobornyl acrylate, and polyethylene glycol diacrylates, oligoester acrylates, urethanes. Acrylate-based compounds such as acrylate oligomers, epoxy-modified acrylates, polyether acrylates, and itaconic acid oligomers are used. The energy ray curable resin (a1) is used alone or in combination of two or more.

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

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

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

The first pressure-sensitive adhesive layer 12 preferably contains 10 parts by mass or more of the energy ray-curable resin (ax1) with respect to 100 parts by mass of the (meth) acrylic copolymer (b1), preferably 20 parts by mass. It is more preferable to contain it in the above ratio, and it is further preferable to contain it in a ratio of 25 parts by mass or more.
The first pressure-sensitive adhesive layer 12 preferably contains 80 parts by mass or less of the energy ray-curable resin (ax1) with respect to 100 parts by mass of the (meth) acrylic copolymer (b1), preferably 70 parts by mass. It is more preferably contained in the following ratio, and further preferably contained in a ratio of 60 parts by mass or less.

The weight average molecular weight (Mw) of the (meth) acrylic copolymer (b1) is preferably 10,000 or more, more preferably 150,000 or more, and further preferably 200,000 or more.
The weight average molecular weight (Mw) of the (meth) acrylic copolymer (b1) is preferably 1.5 million or less, more preferably 1 million or less.
The weight average molecular weight (Mw) in the present specification is a value in terms of standard polystyrene measured by a gel permeation chromatography method (GPC method).

The (meth) acrylic copolymer (b1) is a (meth) acrylic acid ester polymer (b2) into which a functional group (energy ray-curable group) having energy ray curability is introduced into the side chain (hereinafter, "energy"). It may be referred to as a linear curable polymer (b2) ”).

-Energy ray curable polymer (b2)
The energy ray-curable polymer (b2) is 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. It is preferable that it is a copolymer obtained from the above.

As used herein, the term (meth) acrylic acid ester means both an acrylic acid ester and a methacrylic acid ester. The same applies to other similar terms.

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

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

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

Examples of the carboxy group-containing monomer include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. The carboxy group-containing monomer may be used alone 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 and n-butylaminoethyl (meth) acrylate. The amino group-containing monomer or the substituted amino group-containing monomer may be used alone or in combination of two or more.

The (meth) acrylic acid ester monomer constituting the acrylic copolymer (b21) includes an alkyl (meth) acrylate having an alkyl group having 1 or more and 20 or less carbon atoms, and for example, an alicyclic structure in the molecule. A monomer having an alicyclic structure (monomer containing an alicyclic structure) is preferably used.

As the alkyl (meth) acrylate, an alkyl (meth) acrylate having an alkyl group having 1 or more and 18 or less carbon atoms is preferable. As the alkyl (meth) acrylate, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate and the like are more preferable. Alkyl (meth) acrylates may be used alone or in combination of two or more.

Examples of the alicyclic structure-containing monomer include cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, adamantyl (meth) acrylate, isobornyl (meth) acrylate, and dicyclopentenyl (meth) acrylate. , And dicyclopentenyloxyethyl (meth) acrylate and the like are preferably used. The alicyclic structure-containing monomer may be used alone or in combination of two or more.

The acrylic copolymer (b21) preferably contains the structural unit derived from the functional group-containing monomer in a proportion of 1% by mass or more, more preferably in a proportion of 5% by mass or more. It is more preferable to contain it in a proportion of mass% or more.
Further, the acrylic copolymer (b21) preferably contains the structural unit derived from the functional group-containing monomer in a proportion of 35% by mass or less, and more preferably in a proportion of 30% by mass or less. , 25% by mass or less is more preferable.

Further, the acrylic copolymer (b21) preferably contains a structural unit derived from the (meth) acrylic acid ester monomer or a derivative thereof in a proportion of 50% by mass or more, and preferably in a proportion of 60% by mass or more. It is more preferable that the content is 70% by mass or more.
Further, the acrylic copolymer (b21) preferably contains a structural unit derived from the (meth) acrylic acid ester monomer or a derivative thereof in a proportion of 99% by mass or less, and preferably in a proportion of 95% by mass or less. It is more preferable that the content is 90% by mass or less.

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

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, the energy ray-curable polymer (b2) ) Is obtained.

The functional group of the unsaturated group-containing compound (b22) can be appropriately selected depending on the type of the functional group of the functional group-containing monomer unit of the acrylic copolymer (b21). For example, when the functional group of the acrylic copolymer (b21) is a hydroxy 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 acrylic. When the functional group of the system copolymer (b21) is an epoxy group, the functional group of the unsaturated group-containing compound (b22) is preferably an amino group, a carboxy group or an aziridinyl group.

The unsaturated group-containing compound (b22) contains at least one energy ray-polymerizable carbon-carbon double bond in one molecule, preferably one or more and six or less, and preferably one or more and four. It is more preferable to include the following.

Examples of the unsaturated group-containing compound (b22) include 2-methacryloyloxyethyl isocyanate (2-isocyanatoethyl methacrylate), meta-isopropenyl-α, α-dimethylbenzyl isocyanate, methacryloyl isocyanate, and allyl isocyanate, 1,1. -(Bisacryloyloxymethyl) ethyl isocyanate; acryloyl monoisocyanate compound obtained by reacting a diisocyanate compound or polyisocyanate compound with hydroxyethyl (meth) acrylate; a diisocyanate compound or polyisocyanate compound, a polyol compound, and hydroxyethyl ( Acryloyl monoisocyanate compound obtained by reaction with meta) acrylate; glycidyl (meth) acrylate; (meth) acrylic acid, 2- (1-aziridinyl) ethyl (meth) acrylate, 2-vinyl-2-oxazoline, 2-iso Examples thereof include propenyl-2-oxazolin.

The unsaturated group-containing compound (b22) is preferably used in a proportion of 50 mol% or more (addition rate) with respect to the number of moles of the functional group-containing monomer of the acrylic copolymer (b21), preferably 60 mol%. It is more preferably used in the above ratio, and further preferably used in the ratio of 70 mol% or more.
The unsaturated group-containing compound (b22) is preferably used in a proportion of 95 mol% or less, preferably 93 mol% or less, based on the number of moles of the functional group-containing monomer of the acrylic copolymer (b21). It is more preferably used, and further preferably used in a proportion of 90 mol% or less.

In the reaction between the acrylic copolymer (b21) and the unsaturated group-containing compound (b22), the functional group of the acrylic copolymer (b21) and the functional group of the unsaturated group-containing compound (b22) are used. Depending on the combination, the reaction temperature, pressure, solvent, time, presence / absence of catalyst, and type of polymer can be appropriately selected. As a result, the functional group of the acrylic copolymer (b21) reacts with the functional group of the unsaturated group-containing compound (b22), and the unsaturated group becomes a side chain of the acrylic copolymer (b21). Introduced to give the energy ray curable polymer (b2).

The weight average molecular weight (Mw) of the energy ray-curable polymer (b2) is preferably 10,000 or more, more preferably 150,000 or more, and even more preferably 200,000 or more.
The weight average molecular weight (Mw) of the energy ray-curable polymer (b2) is preferably 1.5 million or less, more preferably 1 million or less.

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

Specific examples of the photopolymerization initiator (C) include benzoin compounds, acetophenone compounds, acylphosphinoxide compounds, titanosen compounds, thioxanthone compounds and peroxide compounds. Further, examples of the photopolymerization initiator (C) include a photosensitizer such as amine or quinone.
As a more specific photopolymerization initiator (C), for example, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propane-1-one, benzoin, benzoin methyl ether, benzoin Ethyl ether, benzoin isopropyl ether, benzylphenyl sulfide, tetramethylthium monosulfide, azobisisobutyrolnitrile, dibenzyl, diacetyl, 8-chloranthraquinone and bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide Can be mentioned. As the photopolymerization initiator (C), one type may be used alone, or two or more types may be used in combination.

The blending amount of the photopolymerization initiator (C) is preferably 0.01 part by mass or more and 10 parts by mass or less, and 0.03 part by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the adhesive resin. It is more preferably 0.05 parts by mass or more, and further preferably 5 parts by mass or less.

The photopolymerization initiator (C) is an energy ray-curable resin (ax1) when the energy ray-curable resin (ax1) and the (meth) acrylic copolymer (b1) are blended in the pressure-sensitive adhesive layer. The amount of the (meth) acrylic copolymer (b1) is preferably 0.1 parts by mass or more with respect to 100 parts by mass, and more preferably 0.5 parts by mass or more. preferable.
Further, the photopolymerization initiator (C) is an energy ray-curable resin (ax1) when the energy ray-curable resin (ax1) and the (meth) acrylic copolymer (b1) are blended in the pressure-sensitive adhesive layer. ) And (meth) acrylic copolymer (b1) in an amount of 10 parts by mass or less, more preferably 6 parts by mass or less with respect to 100 parts by mass.

The first pressure-sensitive adhesive layer 12 may contain other components as appropriate in addition to the above components. Examples of other components include a cross-linking agent (E) and the like.

・ Crosslinking agent (E)
As the cross-linking agent (E), a polyfunctional compound having reactivity with a functional group of the (meth) acrylic copolymer (b1) or the like can be used. Examples of the polyfunctional compound in the first pressure-sensitive adhesive sheet 10 include an isocyanato compound, an epoxy compound, an amine compound, a melamine compound, an aziridine compound, a hydrazine compound, an aldehyde compound, an oxazoline compound, a metal alkoxide compound, a metal chelate compound, and a metal salt. , Ammonium salt, reactive phenol resin and the like.

The blending amount of the cross-linking agent (E) is preferably 0.01 part by mass or more, and preferably 0.03 part by mass or more with respect to 100 parts by mass of the (meth) acrylic copolymer (b1). It is more preferably 0.04 part by mass or more, and further preferably 0.04 part by mass or more.
The amount of the cross-linking agent (E) to be blended is preferably 8 parts by mass or less, more preferably 5 parts by mass or less, based on 100 parts by mass of the (meth) acrylic copolymer (b1). , 3.5 parts by mass or less is more preferable.

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

The restoration rate of the first pressure-sensitive adhesive sheet 10 is preferably 70% or more, more preferably 80% or more, and further preferably 85% or more. The restoration rate of the first adhesive sheet 10 is preferably 100% or less. When the restoration rate is within the above range, the pressure-sensitive adhesive sheet can be greatly stretched.
The restoration rate is determined by grasping both ends in the length direction with a gripping tool so that the length between the gripping tools is 100 mm in the test piece obtained by cutting the adhesive sheet into 150 mm (length direction) × 15 mm (width direction). After that, it is pulled at a speed of 200 mm / min until the length between the grips becomes 200 mm, and the length between the grips is extended to 200 mm and held for 1 minute, and then the length between the grips is 100 mm. Return to the length direction at a speed of 200 mm / min, hold for 1 minute with the length between the grips returned to 100 mm, and then pull in the length direction at a speed of 60 mm / min to pull the force. The length between the gripping tools when the measured value of was 0.1 N / 15 mm was measured, and the length obtained by subtracting the initial length between the gripping tools of 100 mm from the length was defined as L2 (mm). It is calculated by the following formula (Equation 2), where L1 (mm) is the length obtained by subtracting the length of 100 mm between the initial grips from the length of 200 mm between the grips in the expanded state.
Restoration rate (%) = {1- (L2 ÷ L1)} × 100 ・ ・ ・ (Number 2)

When the restoration rate is in the above range, it means that the pressure-sensitive adhesive sheet can be easily restored even after being greatly stretched. Generally, when a sheet having a yield point is stretched beyond the yield point, the sheet undergoes plastic deformation, and the plastically deformed portion, that is, the extremely stretched portion is unevenly distributed. When the sheet in such a state is further stretched, the expansion becomes non-uniform even if the extremely stretched portion is broken or does not break. Further, in the stress-strain diagram in which strain is plotted on the x-axis and elongation is plotted on the y-axis, the slope dx / dy does not take a stress value that changes from a positive value to 0 or a negative value, and is a clear yield point. Even if the sheet does not show the above, the sheet undergoes plastic deformation as the tensile amount increases, and similarly, fracture occurs and the expansion becomes non-uniform. On the other hand, when elastic deformation occurs instead of plastic deformation, the sheet can be easily restored to its original shape by removing the stress. Therefore, when the restoration rate, which is an index indicating how much restoration is performed after 100% elongation, which is a sufficiently large tensile amount, is within the above range, the plastic deformation of the film is minimized when the pressure-sensitive adhesive sheet is greatly stretched. It is suppressed, is less likely to break, and enables uniform expansion.

-A release sheet may be attached to the surface of the first adhesive sheet 10. Specifically, the release sheet is attached to the surface of the first pressure-sensitive adhesive layer 12 of the first pressure-sensitive adhesive sheet 10. The release sheet is attached to the surface of the first pressure-sensitive adhesive layer 12 to protect the first pressure-sensitive adhesive layer 12 during transportation and storage. The release sheet is releasably attached to the first pressure-sensitive adhesive sheet 10, and is peeled off from the first pressure-sensitive adhesive sheet 10 before the first pressure-sensitive adhesive sheet 10 is used.

As the release sheet, a release sheet in which at least one surface has been peeled is used. Specific examples thereof include a release sheet including a base material for a release sheet and a release agent layer formed by applying a release agent on the surface of the base material.

A resin film is preferable as the base material for the release sheet. Examples of the resin constituting the resin film as the base material for the release sheet include polyester resin films such as polyethylene terephthalate resin, polybutylene terephthalate resin and polyethylene naphthalate resin, and polyolefin resins such as polypropylene resin and polyethylene resin. Be done.
Examples of the release agent include rubber-based elastomers such as silicone-based resins, olefin-based resins, isoprene-based resins, and butadiene-based resins, long-chain alkyl-based resins, alkyd-based resins, and fluorine-based resins.

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

-Method for manufacturing the pressure-sensitive adhesive sheet The first pressure-sensitive adhesive sheet 10 and other methods for manufacturing the pressure-sensitive adhesive sheet described in the present specification are not particularly limited and can be manufactured by a known method.

For example, the pressure-sensitive adhesive layer provided on the release sheet can be bonded to one side of the base material to produce a pressure-sensitive adhesive sheet to which the release sheet is attached to the surface of the pressure-sensitive adhesive layer. Further, by adhering the cushioning layer provided on the release sheet and the base material and removing the release sheet, a laminate of the buffer layer and the base material can be obtained. Then, the pressure-sensitive adhesive layer provided on the release sheet can be bonded to the base material side of the laminate to produce a pressure-sensitive adhesive sheet in which the release sheet is attached to the surface of the pressure-sensitive adhesive layer. When the cushioning layer is provided on both sides of the base material, the pressure-sensitive adhesive layer is formed on the cushioning layer. The release sheet attached to the surface of the pressure-sensitive adhesive layer may be appropriately peeled off and removed before the use of the pressure-sensitive adhesive sheet.

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

Further, as another specific example of the method for manufacturing the pressure-sensitive adhesive sheet, the following method can be mentioned. First, a coating liquid is applied on the peeled surface of the above-mentioned peeling 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 base material may be attached to the surface of the pressure-sensitive adhesive layer of the laminated body opposite to the surface on the release sheet side to obtain a laminated body of the pressure-sensitive adhesive sheet and the release sheet. The release sheet in this laminate may be peeled off as a process material, or protects the pressure-sensitive adhesive layer until an adherend (for example, a semiconductor chip, a semiconductor wafer, etc.) is attached to the pressure-sensitive adhesive layer. May be good.

When the coating liquid contains a cross-linking agent, for example, by changing the drying conditions (for example, temperature, time, etc.) of the coating film, or by separately performing a heat treatment, for example, in the coating film. The cross-linking reaction between the (meth) acrylic copolymer and the cross-linking agent may be allowed to proceed to form a cross-linked structure in the pressure-sensitive adhesive layer at a desired abundance density. In order to allow this cross-linking reaction to proceed sufficiently, after laminating the pressure-sensitive adhesive layer on the substrate by the above-mentioned method or the like, the obtained pressure-sensitive adhesive sheet is allowed to stand in an environment of, for example, 23 ° C. and a relative humidity of 50% for several days. You may perform curing such as placing.

The thickness of the first pressure-sensitive adhesive sheet 10 is preferably 60 μm or more, more preferably 70 μm or more, and further preferably 80 μm or more. The thickness of the first pressure-sensitive adhesive sheet 10 is preferably 400 μm or less, more preferably 300 μm or less.

[Effects of the present embodiment]
According to the expanding method according to the present embodiment, by using the first pressure-sensitive adhesive sheet 10 having the first base material 11 and the first pressure-sensitive adhesive layer 12, the dicing step and the expanding step can be combined with one pressure-sensitive adhesive sheet (first pressure-sensitive adhesive sheet). It can be carried out on the sheet 10). That is, according to the expanding method according to the present embodiment, it is not necessary to replace the adhesive sheet for each process as in the conventional process, and the process can be simplified.
Further, according to the first pressure-sensitive adhesive sheet 10, since the tensile elongation of the first base material 11 having a notch having a depth of 50 μm is 300% or more, the first base material 11 is cut to a predetermined depth in the dicing step. Even if the first pressure-sensitive adhesive sheet 10 is stretched as it is in the expanding step, the distance between the plurality of semiconductor chip CPs can be expanded without breaking the first pressure-sensitive adhesive sheet 10. Therefore, as compared with the conventional pressure-sensitive adhesive sheet (the pressure-sensitive adhesive sheet in which the pressure-sensitive adhesive layer and the two base material layers are laminated), the first pressure-sensitive adhesive sheet 10 has a simple tape structure and can simplify the process.
Further, according to the present embodiment, it is possible to provide a method for manufacturing a semiconductor device including the expanding method according to the present embodiment.

[Modification of Embodiment]
The present invention is not limited to the above-described embodiment. The present invention includes an embodiment obtained by modifying the above-described embodiment to the extent that the object of the present invention can be achieved.

For example, circuits and the like in semiconductor wafers and semiconductor chips are not limited to the arrangements and shapes 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-described embodiment. In the above-described embodiment, the embodiment of manufacturing the FO-WLP type semiconductor package has been described as an example, but the present invention can also be applied to the embodiment of manufacturing other semiconductor packages such as a fan-in type WLP.

In the above-mentioned FO-WLP manufacturing method, some steps may be changed or some steps may be omitted.

Dicing in the dicing step may be performed by irradiating the semiconductor wafer with a laser beam instead of using the cutting means described above. For example, the semiconductor wafer may be completely divided by irradiation with a laser beam and individualized into a plurality of semiconductor chips. In these methods, the irradiation of the laser beam may be performed from either side of the semiconductor wafer.

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

(Making an adhesive sheet)
[Example 1]
62 parts by mass of butyl acrylate (BA), 10 parts by mass of methyl methacrylate (MMA), and 28 parts by mass of 2-hydroxyethyl acrylate (2HEA) were copolymerized to obtain an acrylic copolymer. A solution of a resin (acrylic A) to which 2-isocyanatoethyl methacrylate (manufactured by Showa Denko KK, product name "Karenzu MOI" (registered trademark)) is added to this acrylic copolymer (adhesive main agent, solid). Minutes 35.0% by mass) were prepared. The addition rate was 90 mol% of 2-isocyanate ethyl methacrylate with respect to 100 mol% of 2HEA of the acrylic copolymer.
The weight average molecular weight (Mw) of the obtained resin (acrylic A) was 600,000, and Mw / Mn was 4.5. The weight average molecular weight Mw and the number average molecular weight Mn in terms of standard polystyrene were measured by gel permeation chromatography (GPC) method, and the molecular weight distribution (Mw / Mn) was obtained from each measured value.
This pressure-sensitive adhesive main agent contains UV resin A (10-functional urethane acrylate, manufactured by Mitsubishi Chemical Co., Ltd., product name "UV-5806", Mw = 1740, including photopolymerization initiator), and tolylene diisocyanate as a cross-linking agent. A system cross-linking agent (manufactured by Nippon Polyurethane Industry Co., Ltd., product name "Coronate L") was added. 50 parts by mass of UV resin A was added and 0.2 parts by mass of a cross-linking agent was added to 100 parts by mass of the solid content in the main agent of the pressure-sensitive adhesive. After the addition, the mixture was stirred for 30 minutes to prepare the pressure-sensitive adhesive composition A1.
Next, the prepared solution of the pressure-sensitive adhesive composition A1 was applied to a polyethylene terephthalate (PET) -based release film (manufactured by Lintec Corporation, product name "SP-PET38131", thickness 38 μm) and dried to obtain a pressure-sensitive adhesive having a thickness of 40 μm. The agent layer was formed on the release film. In this embodiment, this pressure-sensitive adhesive layer may be referred to as a first pressure-sensitive adhesive layer in correspondence with the description in the above-described embodiment.
A polyester-based polyurethane elastomer sheet (manufactured by Seadam Co., Ltd., product name "Higres DUS202", thickness 100 μm) as a base material is bonded to the first adhesive layer, and then unnecessary portions at the ends in the width direction are cut. It was removed to prepare an adhesive sheet SA1. In this embodiment, this base material may be referred to as a first base material in correspondence with the description in the above embodiment. When a notch having a depth of 50 μm was made in the first base material and the tensile elongation of the first base material was measured, it was found to be 300% or more. According to the above-mentioned method for measuring the tensile elongation, the tensile elongation of the first base material after making a cut was measured.

(Measuring method of chip spacing)
The adhesive sheet SA1 obtained in Example 1 was cut into 210 mm × 210 mm to obtain a test sheet. At this time, each side of the sheet after cutting was cut so as to be parallel or perpendicular to the MD direction of the first base material in the adhesive sheet.
The release film of the test sheet was peeled off, and a 6-inch silicon wafer was attached to the center of the exposed first pressure-sensitive adhesive layer. Next, a 6-inch silicon wafer was diced to obtain a total of 25 chips having a size of 3 mm × 3 mm. A total of 25 chips obtained by dicing were arranged in 5 rows in the X-axis direction and 5 rows in the Y-axis direction. When dicing the silicon wafer, the test sheet also had a notch with a depth of 50 μm.

Next, the test sheet to which the chip was attached was installed in an expander (separation device) capable of biaxial stretching. FIG. 5 shows a plan view illustrating the expanding device 100. In FIG. 5, the X-axis and the Y-axis are in a relationship orthogonal to each other, the positive direction of the X-axis is the + X-axis direction, the negative direction of the X-axis is the −X-axis direction, and the positive direction of the Y-axis. Is the + Y-axis direction, and the negative direction of the Y-axis is the −Y-axis direction. The test sheet 200 was installed in the expanding device 100 so that each side was parallel to the X-axis or the Y-axis. As a result, the MD direction of the base material in the test sheet 200 is parallel to the X-axis or the Y-axis. In FIG. 5, the chip is omitted.

As shown in FIG. 5, the expanding device 100 includes five holding means 101 (a total of 20 holding means 101) in each of the + X-axis direction, the −X-axis direction, the + Y-axis direction, and the −Y-axis direction. Of the five holding means 101 in each direction, the holding means 101A is located at both ends, the holding means 101C is located at the center, and the holding means 101B is located between the holding means 101A and the holding means 101C. Each side of the test sheet 200 was gripped by these holding means 101.

Here, as shown in FIG. 5, one side of the test sheet 200 is 210 mm. Further, the distance between the holding means 101 on each side is 40 mm. Further, the distance between the end portion (the apex of the sheet) on one side of the test sheet 200 and the holding means 101A existing on the side and closest to the end portion is 25 mm.

Subsequently, a plurality of tension applying means (not shown) corresponding to each of the holding means 101 were driven to move the holding means 101 independently. The four sides of the test sheet were fixed with a gripping jig, and the test sheet was expanded with an expansion amount of 200 mm at a speed of 5 mm / s in the X-axis direction and the Y-axis direction, respectively. After that, the expanded state of the test sheet 200 was held by the ring frame.
The distance between the chips was measured with a digital microscope while the expanded state was maintained, and the average value of the distances between the chips was taken as the chip spacing.
If the chip spacing is 1800 μm or more, it is determined to be “A”, and if the chip spacing is less than 1800 μm, it is determined to be rejected “B”.

(Measuring method of chip alignment)
The deviation rate from the center line of the adjacent chips in the X-axis and Y-axis directions of the work whose chip spacing was measured was measured.
FIG. 6 shows a schematic diagram of a specific measurement method.
One row in which five chips were arranged in the X-axis direction was selected, and the distance Dy between the uppermost end of the chips and the lowermost end of the chips in the row was measured with a digital microscope. The deviation rate in the Y-axis direction was calculated based on the following mathematical formula (Equation 3). Sy is the chip size in the Y-axis direction, and is set to 3 mm in this embodiment.
Deviation rate in the Y-axis direction [%] = [(Dy-Sy) / 2] / Sy × 100 ... (Equation 3)
The deviation rate in the Y-axis direction was calculated in the same manner for the other four rows in which five chips were arranged in the X-axis direction.
One row in which five chips were arranged in the Y-axis direction was selected, and the distance Dx between the leftmost end of the chips and the rightmost end of the chips in the row was measured with a digital microscope. The deviation rate in the X-axis direction was calculated based on the following mathematical formula (Equation 4). Sx is the chip size in the X-axis direction, and is set to 3 mm in this embodiment.
Deviation rate in the X-axis direction [%] = [(Dx-Sx) / 2] / Sx × 100 ... (Equation 4)
The deviation rate in the X-axis direction was calculated in the same manner for the other four rows in which five chips were arranged in the Y-axis direction.
In the mathematical formulas (Equation 3) and (Equation 4), the reason for dividing by 2 is to express the maximum distance deviated from the predetermined position of the chip after expansion as an absolute value.
If the deviation rate is less than ± 10% in all rows in the X-axis direction and Y-axis direction (10 rows in total), it is judged as pass "A", and if it is ± 10% or more in one or more rows, it is not acceptable. It was judged as a pass "B".

When the pressure-sensitive adhesive sheet according to Example 1 was expanded, the distance between the plurality of semiconductor chip CPs could be expanded without breaking the pressure-sensitive adhesive sheet. Further, the evaluation result of the chip interval after expanding the adhesive sheet was a pass "A" judgment, and the evaluation result of the chip alignment was a pass "A" judgment.

10 ... 1st adhesive sheet, 11 ... 1st base material, 12 ... 1st adhesive layer, CP ... semiconductor chip, W ... semiconductor wafer (wafer), W1 ... circuit surface (1st wafer surface), W2 ... circuit, W3 ... Back surface (second wafer surface).

Claims (11)

A first adhesive sheet having a first pressure-sensitive adhesive layer and a first base material is attached to the second wafer surface of a wafer having a first wafer surface and a second wafer surface opposite to the first wafer surface. The tensile elongation of the first substrate having a notch with a depth of 50 μm is 300% or more.
A notch is made from the surface side of the first wafer, the wafer is fragmented into a plurality of chips, and the first pressure-sensitive adhesive layer of the first pressure-sensitive adhesive sheet is cut.
The first adhesive sheet is stretched to widen the space between the plurality of chips.
Expanding method. In the expanding method according to claim 1,
The notch is formed at a depth from the surface side of the first wafer until it reaches the first base material.
Expanding method. In the expanding method according to claim 2,
The thickness of the first base material is T1.
The depth T2 of the cut made in the first substrate is 0.2 × T1 or less.
Expanding method. In the expanding method according to any one of claims 1 to 3.
The first substrate contains a thermoplastic elastomer.
Expanding method. In the expanding method according to any one of claims 1 to 4.
The first base material contains a urethane-based elastomer.
Expanding method. In the expanding method according to any one of claims 1 to 5.
The first pressure-sensitive adhesive layer contains an energy ray-curable resin.
Expanding method. In the expanding method according to claim 6,
After stretching the first pressure-sensitive adhesive sheet to widen the space between the plurality of chips, the first pressure-sensitive adhesive layer is irradiated with energy rays to cure the first pressure-sensitive adhesive layer.
Expanding method. In the expanding method according to any one of claims 1 to 7.
The first adhesive sheet is an expand sheet.
Expanding method. In the expanding method according to any one of claims 1 to 8.
The wafer is a semiconductor wafer.
Expanding method. In the expanding method according to any one of claims 1 to 9.
The first wafer surface has a circuit.
Expanding method. A method for manufacturing a semiconductor device, which comprises the expanding method according to any one of claims 1 to 10.

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