TW202142658A - Adhesive sheet - Google Patents

Abstract

This adhesive sheet comprises a substrate and an adhesive layer, the substrate not containing chlorine atoms. When a reference direction is any one direction in plan view of the substrate, and a first measurement direction is a direction in which the amount of rise of tensile stress, obtained by subtracting the tensile stress at 100% elongation from the tensile stress at 200% elongation, is smallest among a total of 18 directions in which an angle formed with the reference direction in plan view is 0 DEG, 10 DEG, 20 DEG, 30 DEG, 40 DEG, 50 DEG, 60 DEG, 70 DEG, 80 DEG, 90 DEG, 100 DEG, 110 DEG, 120 DEG, 130 DEG, 140 DEG, 150 DEG, 160 DEG, and 170 DEG, then all tensile stresses from 10% elongation to 100% elongation in the first measurement direction are in a range of 8-30 MPa, and all tensile stresses from 100% elongation to 200% elongation in the first measurement direction are in a range of 10-40 MPa. The adhesive sheet has excellent expandability.

Description

Adhesive sheet

The present invention relates to an adhesive sheet that can be applied to a workpiece processing sheet used in the processing of a workpiece such as a semiconductor wafer.

Semiconductor wafers such as silicon and gallium arsenide and various packages are manufactured in a large-scale state. After cutting (dicing) into wafers and peeling (pickup), they are transferred to the next assembly process. At this time, the workpiece such as a semiconductor wafer is attached to an adhesive sheet (hereinafter sometimes referred to as a "workpiece processing sheet") including a base material and an adhesive layer, and the wafer is ground, cut, and diced. Processing such as cleaning, drying, expanding, picking, and assembling.

As one of the above-mentioned cutting methods, there is a method of cutting the workpiece with a rotating circular blade (cutting knife). In this method, in order to ensure that the workpiece is cut, usually the workpiece processing sheet attached to the workpiece is also partially cut together with the workpiece. In the case where the workpiece processing sheet is cut together with the workpiece in this manner, the workpiece processing sheet may generate cutting chips formed by the materials constituting the adhesive layer and the base material.

If the chip is directly sealed when a large amount of chips are attached to the chip, the chips attached to the chip will be decomposed by the heat of the sealing. This thermal decomposition product will damage the package or cause the operation of the resulting device. Causes of defects, etc. Since it is difficult to remove such cutting chips by cleaning, the production of cutting chips significantly reduces the productivity of the cutting process. Therefore, in the case of cutting with a rotating circular blade, it is necessary to prevent the generation of cutting chips.

For the purpose of suppressing the generation of cutting chips, Patent Document 1 discloses an invention that uses a polyolefin-based film irradiated with 1 to 80 Mrad of electron beams or γ (gamma) rays as the base film of the dicing sheet . It is considered that in this invention, the crosslinking of covalent bonds is formed in the resin constituting the base film by irradiation of electron beams or gamma rays, thereby suppressing the generation of cutting chips. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 5-211234

[The problem to be solved by the invention]

In the above-mentioned pickup process, in order to easily pick up the semiconductor wafers, the semiconductor wafers may be individually picked up from the surface of the workpiece processing sheet opposite to the surface on which the semiconductor wafers are laminated. In particular, in order to suppress collisions between the semiconductor wafers during pick-up and facilitate pick-up at the same time, the workpiece processing sheet is usually extended (expanded) so that the semiconductor wafers are separated from each other. Therefore, the sheet for workpiece processing needs to have excellent flexibility that can be expanded well.

However, the conventional dicing sheet disclosed in Patent Document 1 does not have sufficient expandability.

The present invention was completed in view of this situation, and aims to provide an adhesive sheet with good expandability. [Means used to solve the problem]

In order to achieve the above object, first of all, the present invention provides an adhesive sheet comprising a substrate and an adhesive layer laminated on one surface side of the substrate, wherein the substrate does not contain chlorine atoms, and Taking any one direction of the plane viewing angle of the aforementioned substrate as the reference direction, the angle formed between the aforementioned reference direction and the plane viewing angle is 0°, 10°, 20°, 30°, 40°, 50°, 60°, Among 18 directions of 70°, 80°, 90°, 100°, 110°, 120°, 130°, 140°, 150°, 160° and 170°, the tensile stress at 200% elongation is reduced In the case where the direction in which the increase in tensile stress obtained by the tensile stress at 100% elongation is the smallest is set as the first measurement direction, for the substrate, in the first measurement direction, from 10% elongation to elongation The tensile stress at 100% is all within the range of 8 MPa or more and 30 MPa or less, and for the aforementioned substrate, in the aforementioned first measurement direction, the tensile stress from 100% elongation to 200% elongation is all Within the range of 10 MPa or more and 40 MPa or less (Invention 1).

According to the adhesive sheet of the aforementioned invention (Invention 1), since the base material satisfies the aforementioned conditions of tensile stress, it has excellent flexibility and can be expanded well.

In the above invention (Invention 1), for the substrate, the increase in tensile stress obtained by subtracting the tensile stress at 200% elongation by the tensile stress at 100% elongation in the first measurement direction 1 MPa or more and 20 MPa or less are preferable (Invention 2).

In the above inventions (Inventions 1 and 2), when one direction of the planar viewing angle of the substrate and a direction formed by an angle of 90° with the first measurement direction is set as the second measurement direction, For the aforementioned substrate, in the aforementioned second measurement direction, the tensile stress from 10% elongation to 100% elongation is preferably all within the range of 5 MPa or more and 30 MPa or less, and for the aforementioned substrate, In the aforementioned second measurement direction, it is preferable that all the tensile stresses from 100% elongation to 200% elongation are within the range of 10 MPa or more and 40 MPa or less (Invention 3).

In the aforementioned invention (Invention 3), for the aforementioned substrate, the increase in tensile stress obtained by subtracting the tensile stress at 200% elongation by the tensile stress at 100% elongation in the aforementioned second measurement direction 1 MPa or more and 20 MPa or less are better (Invention 4).

In the above inventions (Inventions 1 to 4), the tensile modulus of the substrate in the first measurement direction is preferably 100 MPa or more and 1000 MPa or less (Invention 5).

In the above inventions (Inventions 1 to 5), the elongation at break of the substrate in the first measurement direction is preferably 100% or more and 1000% or less (Invention 6).

In the aforementioned inventions (Inventions 1 to 6), the results measured when the aforementioned substrate is subjected to the tensile test in the aforementioned first measurement direction are plotted on the basis of the tensile elongation (unit: %) as the horizontal The curve obtained on the coordinate plane with the tensile stress (unit: MPa) as the vertical axis is preferably that there is no point that becomes a maximum in the aforementioned curve, or there is at least one point that becomes a maximum in the aforementioned curve, and A point that becomes a minimum value, and the value of the tensile stress at the point where the tensile elongation is the minimum among the points where the maximum value is, and the tensile elongation at the point where the minimum value is The absolute value of the difference between the aforementioned tensile stress values at the point where the ratio is the minimum is preferably 2.0 MPa or less (Invention 7).

In the above inventions (Inventions 1 to 7), the aforementioned substrate preferably does not contain halogen atoms (Invention 8).

Among the above inventions (Inventions 1 to 8), it is preferable to use it as a sheet for workpiece processing (Invention 9).

In the above invention (Invention 9), the aforementioned workpiece processing sheet is preferably a dicing sheet (Invention 10). [Effects of the invention]

The adhesive sheet according to the present invention has good expandability.

Hereinafter, an embodiment of the present invention will be described. The adhesive sheet according to this embodiment includes a base material and an adhesive layer laminated on one surface side of the base material. This adhesive sheet can be used for various applications like general adhesive sheets, but it is particularly suitable for use as a workpiece processing sheet used for processing workpieces such as semiconductor wafers. In particular, the adhesive sheet according to this embodiment is suitable for use as a sheet for picking up workpieces such as semiconductor wafers.

1. The structure of the adhesive sheet (1) Substrate The base material in this embodiment does not contain chlorine atoms. Since it does not contain chlorine atoms, the pressure-sensitive adhesive sheet according to this embodiment can easily reduce the environmental load. In addition, the "no chlorine atom" as used herein also includes the case where a chlorine atom is not substantially contained. That is, the base material in this embodiment may be inadvertently mixed with a very small amount of a component containing a chlorine atom during the manufacturing process, for example. In this case, the content of chlorine atoms in the base material may be 0.005% by mass or less, particularly 0.003% by mass or less, and further, may be 0.0001% by mass or less.

Furthermore, in the case of the substrate in the present embodiment, when the predetermined direction in its planar viewing angle is set as the first measurement direction, the stretching in the first measurement direction from 10% elongation to 100% elongation The stresses are all within the range of 8 MPa or more and 30 MPa or less, and in the first measurement direction, the tensile stresses from 100% elongation to 200% elongation are all within the range of 10 MPa or more and 40 MPa or less.

According to the adhesive sheet of this embodiment, since the base material satisfies these conditions, it has very excellent flexibility. Therefore, when the adhesive sheet according to this embodiment is used for processing a workpiece, it can be expanded well. In this way, in the subsequent pick-up process, it becomes easy to pick up from the back of the wafer, so it becomes possible to perform good pick-up.

Here, the above-mentioned first measurement direction means, in short, the tensile stress from 100% elongation to 200% elongation when the increase in tensile stress becomes the smallest in the case of a tensile test of the base material. direction. More specifically, taking any direction of the planar viewing angle of the substrate as the reference direction, the angle formed between the reference direction and the planar viewing angle is 0°, 10°, 20°, 30°, 40°, 50° , 60°, 70°, 80°, 90°, 100°, 110°, 120°, 130°, 140°, 150°, 160° and 170° in 18 directions. The direction in which the increase in tensile stress obtained by subtracting the tensile stress at 100% elongation from the tensile stress is the smallest is the first measurement direction.

In addition, in the case where the substrate is a resin film as described later, the direction (TD direction) perpendicular to the transport direction at the time of manufacture often coincides with the above-mentioned first measurement direction.

From the viewpoint of achieving good extensibility more effectively, the lower limit of the range of the tensile stress from 10% elongation to 100% elongation is preferably 9 MPa or more, and particularly preferably 10 MPa or more . Furthermore, the upper limit of the range is preferably 25 MPa or less, particularly preferably 20 MPa or less, and more preferably 15 MPa or less.

In addition, from the same viewpoint, the lower limit of the range of the tensile stress from 100% elongation to 200% elongation is preferably 11 MPa or more, and particularly preferably 12 MPa or more. Furthermore, the upper limit of the range is preferably 30 MPa or less, and particularly preferably 20 MPa or less.

In addition, the details of the above-mentioned tensile stress measurement method are as described in the test example described later.

(1-1) Physical properties of base material For the substrate in this embodiment, in the first measurement direction, the increase in tensile stress obtained by subtracting the tensile stress at 200% elongation by the tensile stress at 100% elongation is preferably 1 MPa or more. 1.5 MPa or more is particularly preferable, and 1.8 MPa or more is more preferable. Furthermore, the above-mentioned increase is preferably 20 MPa or less, preferably 15 MPa or less, particularly preferably 10 MPa or less, and more preferably 5 MPa or less. Since the amount of increase is 1 MPa or more, when the pressure-sensitive adhesive sheet according to the present embodiment is expanded, the stress becomes difficult to concentrate on a part of the base material, and it becomes easy to effectively suppress the breakage of the base material. On the other hand, since the increase amount is 20 MPa or less, when the adhesive sheet according to the present embodiment is expanded, the base material becomes easy to stretch uniformly, so that the wafers become easy to separate well. Therefore, by satisfying the above-mentioned increase amount, the adhesive sheet according to the present embodiment has more excellent expandability.

Furthermore, for the substrate in this embodiment, in the first measurement direction, the increase in tensile stress obtained by subtracting the tensile stress at 200% elongation from the tensile stress at 10% elongation is 0.5 MPa or more Preferably, 1 MPa or more is preferable, 1.5 MPa or more is particularly preferable, and 2 MPa or more is more preferable. Furthermore, the above increase amount is preferably 25 MPa or less, particularly preferably 15 MPa or less, and more preferably 5 MPa or less. Since the increase is 0.5 MPa or more, when the pressure-sensitive adhesive sheet according to the present embodiment is expanded, the stress becomes difficult to concentrate on a part of the base material, and therefore it becomes easy to effectively suppress the breakage of the base material. On the other hand, since the amount of increase is 25 MPa or less, when the adhesive sheet according to the present embodiment is expanded, the base material becomes easy to stretch uniformly, so that the wafers become easily and well separated from each other. Therefore, by satisfying the above-mentioned increase amount, the adhesive sheet according to the present embodiment has more excellent expandability.

Furthermore, in the first measurement direction of the substrate in this embodiment, the ratio of the tensile stress at 200% elongation to the tensile stress at 100% elongation is preferably 0.5 or more, particularly preferably 0.75 or more , And more preferably 1 or more. Furthermore, the above ratio is preferably 3 or less, preferably 2.5 or less, particularly preferably 2 or less, and more preferably 1.5 or less. Since the above-mentioned ratio is 0.5 or more, when the pressure-sensitive adhesive sheet according to the present embodiment is expanded, the stress becomes difficult to concentrate on a part of the base material, and it becomes easy to effectively suppress the cracking of the base material. On the other hand, since the above-mentioned ratio is 3 or less, when the adhesive sheet according to the present embodiment is expanded, the base material becomes easy to be stretched uniformly, so that the wafers become easy to separate well. Therefore, by satisfying the above ratio, the adhesive sheet according to the present embodiment has more excellent expandability.

Furthermore, the tensile modulus of the substrate in the present embodiment in the first measurement direction is preferably 100 MPa or more, particularly preferably 200 MPa or more, and more preferably 300 MPa or more. Furthermore, the above-mentioned tensile elastic modulus is preferably 1000 MPa or less, particularly preferably 800 MPa or less, and more preferably 600 MPa or less. Since the above-mentioned tensile modulus of elasticity is 100 MPa or more, the base material in this embodiment becomes easy to have appropriate strength, and the adhesive sheet becomes easy to perform well while having good handleability. Workpiece processing. In addition, when the pressure-sensitive adhesive sheet according to the present embodiment is expanded, the stress becomes difficult to concentrate on a part of the base material, so that it becomes easy to effectively suppress the cracking of the base material. Furthermore, since the above-mentioned tensile modulus of elasticity is 1000 MPa or less, when the adhesive sheet according to the present embodiment is expanded, the base material becomes easy to stretch uniformly, so that the wafers become easily and well separated from each other. Therefore, by making the tensile elastic modulus of the substrate in the first measurement direction fall within the above upper limit and lower limit, the adhesive sheet according to this embodiment has more excellent expandability. In addition, the details of the above-mentioned measuring method of tensile elastic modulus are as described in the test example described later.

Furthermore, in the present embodiment, the elongation at break in the first measurement direction is preferably 100% or more, particularly preferably 200% or more, and more preferably 300% or more. Furthermore, the above-mentioned elongation at break is preferably 1000% or less, particularly preferably 800% or less, and more preferably 600% or less. Since the above-mentioned elongation at break is 100% or more, the base material in the present embodiment becomes easy to have the desired extensibility, and the adhesive sheet according to the present embodiment becomes easy to achieve excellent expandability and pick-up properties. Since the above-mentioned elongation at break is 1000% or less, the workability of the base material becomes more excellent, and it becomes easy to manufacture the desired adhesive sheet. In addition, the details of the above-mentioned measuring method of breaking elongation are as described in the test example described later.

Furthermore, for the base material in this embodiment, the result measured when the tensile test of the front base material is carried out in the first measurement direction is plotted on the basis of the tensile elongation (unit: %) as the horizontal The curve obtained on the coordinate plane with the tensile stress (unit: MPa) as the vertical axis should satisfy either of the following two conditions. (Condition 1) There is no point that becomes a maximum value in the curve (hereinafter sometimes referred to as "maximum point"). (Condition 2) There is at least one point that becomes a maximum value and one point that becomes a minimum value in the curve (hereinafter sometimes referred to as "minimum point"), and among the points that become the maximum value, the tensile elongation is the minimum The absolute value of the difference between the value of the tensile stress at the point where the minimum value is and the value of the tensile stress at the point where the tensile elongation is the minimum is 2.0 MPa or less.

Regarding the above-mentioned conditions 1 and 2, it will be described in more detail with reference to FIG. 1. In Fig. 1, the state _{where the curve C 1} and the curve C ₂ exist in the coordinate plane with the tensile elongation (unit: %) as the horizontal axis and the tensile stress (unit: MPa) as the vertical axis . First, the curve C ₁ is an example when the above condition 1 is satisfied. In the curve C _1, with the tensile elongation increases from 0%, the tensile stress increased correspondingly (However, when a value close to a predetermined tensile stress will become less significant increase). Therefore, _{there is no point in the curve C 1} where the tensile stress changes from an increase to a decrease, that is, a maximum point.

On the other hand, the curve C ₂ is an example when the condition 2 is satisfied. In the curve C _2, in a case where the tensile elongation increases from 0%, the tensile stress is first added to the position of the point A. Then, taking this point A as the end point, the tensile stress begins to decrease. That is, the curve C ₂ has a maximum point called point A. After the point A is exceeded, the tensile elongation is further increased, and then with the point B as the end point, the tensile stress starts from a decrease to an increase, and then continues to increase. That is, the curve C ₂ has a minimum point called point B. Here, since the absolute value of the difference between the tensile stress values of the point A and the point B (the value represented by “△” in FIG. 1) is 2.0 MPa or less, the curve C ₂ becomes to satisfy the condition 2.

In addition, in the curve C ₂ of FIG. 1, there is one maximum point and one minimum point, and condition 2 may be satisfied even when there are complex maximum points and minimum points. In this case, from the existing plural maximum points and minimum points, select the maximum point with the smallest value of tensile elongation and the minimum point with the smallest value of tensile elongation, and according to the difference between the two Whether the absolute value of the difference is 2.0 MPa or less is used to determine whether condition 2 is satisfied.

Since the base material in this embodiment satisfies at least one of the above-mentioned conditions 1 and 2, the adhesive sheet according to this embodiment can easily have excellent expandability. From this point of view, the absolute value difference (Δ) in Condition 2 is preferably 1.8 MPa or less, preferably 1.6 MPa or less, particularly preferably 1.5 MPa or less, more preferably 1.3 MPa or less, and 1.0 Below MPa is the best. On the other hand, the lower limit of the difference (Δ) in the aforementioned absolute value is not particularly limited, and may exceed 0, for example. In addition, the details of the measurement method of whether the above condition 1 and condition 2 are satisfied are as described in the test example described later.

In the case of the substrate in this embodiment, in the case where the direction in which the angle formed between the substrate and the first measurement direction is 90° is set as the second measurement direction in one of the planar viewing angles of the substrate, In the second measurement direction, the tensile stress from 10% elongation to 100% elongation is preferably all within the range of 5 MPa or more and 30 MPa or less, and in the second measurement direction, from the elongation of 100% The tensile stress at 200% elongation is preferably all within the range of 10 MPa or more and 40 MPa or less. Since these conditions are satisfied, the substrate becomes easier to have more excellent flexibility, and it becomes easier to obtain better expandability.

From the viewpoint of achieving good extensibility more effectively, with regard to the second measurement direction, the lower limit of the range of the tensile stress from the time of elongation of 10% to the time of elongation of 100% is 7.5 MPa or more. Better, and more preferably 10 MPa or more. Furthermore, the upper limit of the range is particularly preferably 25 MPa or less, and more preferably 20 MPa or less.

Furthermore, from the same point of view, with regard to the second measurement direction, the lower limit of the range of the tensile stress from 100% elongation to 200% elongation is particularly preferably 11 MPa or more, and 12 MPa The above is better. Furthermore, the upper limit of the range is particularly preferably 35 MPa or less, and more preferably 30 MPa or less.

In addition, the details of the method for measuring the tensile stress in the second measurement direction are as described in the test example described later.

In addition, for the substrate in this embodiment, in the second measurement direction, the increase in tensile stress obtained by subtracting the tensile stress at 200% elongation from the tensile stress at 100% elongation is preferably 1 MPa or more. , 2MPa or more is particularly preferred, and 3MPa or more is more preferred. Furthermore, the above-mentioned increase amount is preferably 20 MPa or less, particularly preferably 15 MPa or less, and more preferably 10 MPa or less. Since the amount of increase is 1 MPa or more, when the pressure-sensitive adhesive sheet according to the present embodiment is expanded, the stress becomes difficult to concentrate on a part of the base material, and it becomes easy to effectively suppress the breakage of the base material. On the other hand, since the increase amount is 20 MPa or less, when the adhesive sheet according to the present embodiment is expanded, the base material becomes easy to stretch uniformly, so that the wafers become easy to separate well. Therefore, by satisfying the above-mentioned increase amount, the adhesive sheet according to the present embodiment has more excellent expandability.

Furthermore, for the substrate in this embodiment, in the second measurement direction, the increase in tensile stress obtained by subtracting the tensile stress at 200% elongation from the tensile stress at 10% elongation is 1 MPa or more Preferably, 2 MPa or more is preferable, 3 MPa or more is particularly preferable, and 4 MPa or more is more preferable. Furthermore, the above-mentioned increase is preferably 30 MPa or less, particularly preferably 25 MPa or less, and more preferably 20 MPa or less. Since the amount of increase is 1 MPa or more, when the pressure-sensitive adhesive sheet according to the present embodiment is expanded, the stress becomes difficult to concentrate on a part of the base material, and it becomes easy to effectively suppress the breakage of the base material. On the other hand, since the increase amount is 30 MPa or less, when the adhesive sheet according to the present embodiment is expanded, the base material becomes easy to stretch uniformly, so that the wafers become easily separated well. Therefore, by satisfying the above-mentioned increase amount, the adhesive sheet according to the present embodiment has more excellent expandability.

Furthermore, for the substrate in this embodiment, the increase in tensile stress obtained by subtracting the tensile stress at 150% elongation from the tensile stress at 50% elongation in the second measurement direction is 0.5 MPa or more Preferably, 1 MPa or more is preferable, 1.5 MPa or more is particularly preferable, and 2 MPa or more is more preferable. Furthermore, the above-mentioned increase amount is preferably 20 MPa or less, particularly preferably 15 MPa or less, and more preferably 10 MPa or less. Since the increase is 0.5 MPa or more, when the pressure-sensitive adhesive sheet according to the present embodiment is expanded, the stress becomes difficult to concentrate on a part of the base material, and therefore it becomes easy to effectively suppress the breakage of the base material. On the other hand, since the increase amount is 20 MPa or less, when the adhesive sheet according to the present embodiment is expanded, the base material becomes easy to stretch uniformly, so that the wafers become easy to separate well. Therefore, by satisfying the above-mentioned increase amount, the adhesive sheet according to the present embodiment has more excellent expandability.

Furthermore, for the substrate in this embodiment, in the second measurement direction, the increase in tensile stress obtained by subtracting the tensile stress at 250% elongation from the tensile stress at 50% elongation is 2 MPa or more Preferably, 4 MPa or more is particularly preferable, 5 MPa or more is more preferable, and 6 MPa or more is further more preferable. Furthermore, the above-mentioned increase is preferably 30 MPa or less, particularly preferably 25 MPa or less, and more preferably 20 MPa or less. Since the amount of increase is 2 MPa or more, when the pressure-sensitive adhesive sheet according to the present embodiment is expanded, the stress becomes difficult to concentrate on a part of the base material, and it becomes easy to effectively suppress the breakage of the base material. On the other hand, since the increase amount is 30 MPa or less, when the adhesive sheet according to the present embodiment is expanded, the base material becomes easy to stretch uniformly, so that the wafers become easily separated well. Therefore, by satisfying the above-mentioned increase amount, the adhesive sheet according to the present embodiment has more excellent expandability.

Furthermore, in the present embodiment, the tensile modulus of elasticity in the second measurement direction is preferably 100 MPa or more, particularly preferably 200 MPa or more, and more preferably 300 MPa or more. Furthermore, the above-mentioned tensile elastic modulus is preferably 1000 MPa or less, particularly preferably 800 MPa or less, and more preferably 600 MPa or less. Since the above-mentioned tensile modulus of elasticity is 100 MPa or more, the base material in this embodiment becomes easy to have appropriate strength, and the adhesive sheet becomes easy to perform well while having good handleability. Workpiece processing. In addition, when the pressure-sensitive adhesive sheet according to the present embodiment is expanded, the stress becomes difficult to concentrate on a part of the base material, so that it becomes easy to effectively suppress the cracking of the base material. Furthermore, since the above-mentioned tensile modulus of elasticity is 1000 MPa or less, when the adhesive sheet according to the present embodiment is expanded, the base material becomes easy to stretch uniformly, so that the wafers become easily and well separated from each other. Therefore, by making the tensile elastic modulus of the substrate in the second measurement direction fall within the range of the above upper limit and lower limit, the adhesive sheet according to this embodiment has more excellent expandability. In addition, the details of the above-mentioned measuring method of tensile elastic modulus are as described in the test example described later.

(1-2) Composition of base material The base material in this embodiment basically does not contain chlorine atoms, and at the same time satisfies the requirements regarding the tensile stress from 10% elongation to 100% elongation and the tensile stress from 100% elongation to 200% elongation. For the aforementioned physical properties, the composition is not limited.

From the viewpoint that the pressure-sensitive adhesive sheet according to the present embodiment can easily exhibit a desired function when used as a workpiece processing sheet, the base material in the present embodiment is preferably a resin film having a resin-based material as a main component.

Examples of the above-mentioned resins include polyolefins such as polyethylene, polypropylene, polybutene, polybutadiene, polymethylpentene, ethylene-norbornene copolymer, norbornene resin; Polyester resins such as ethylene phthalate, polybutylene terephthalate, and polyethylene naphthalate; ethylene-vinyl acetate copolymer; ethylene-(meth)acrylic acid copolymer, ethylene -(Meth)acrylate copolymer; other ethylene-(meth)acrylate copolymers and other vinyl copolymers; (meth)acrylate copolymer; polyurethane; polyimide; polystyrene ; Polycarbonate; Fluororesin etc. Furthermore, modified resins such as crosslinked resins and ionomer resins of these resins may also be used. In addition, in this specification, the "(meth)acrylic" type means both acrylic acid and methacrylic acid. The same goes for other similar terms. Furthermore, the "polymer" in this specification also includes the concept of "copolymer".

In addition, the base material in this embodiment may be a laminated film formed by laminating a plurality of layers of the above-mentioned resin film. In this laminated film, the materials constituting each layer may be of the same kind or different kinds.

Among the above resins, it is preferable to use at least one of fluororesin, polyurethane, and polyester resin. Especially in films using these resins, the content of the main component resin (fluororesin, polyurethane or polyester resin) is preferably 50% by mass or more, preferably 60% by mass or more, and particularly 70% by mass or more. Preferably, it is more preferably 80% by mass or more. By using these films, it becomes easy to satisfy the physical properties regarding the aforementioned tensile stress.

Examples of fluororesins include polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene (ETFE), tetrafluoroethylene/hexafluoroethylene (FEP), perfluoroalkoxy alkane (PFA), polyvinylidene Vinyl fluoride (PVdF) and so on. Among the above, polytetrafluoroethylene (PTFE) is particularly preferred.

As an example of the above-mentioned polyurethane, polyurethane elastomer can be cited, and among them, thermoplastic polyurethane elastomer (TPU) is preferred.

Thermoplastic polyurethane elastomers are usually obtained by reacting long-chain polyols, chain extenders, and polyisocyanates, and are composed of soft segments with structural units derived from long-chain polyols, and chain extenders and polyisocyanates. The reaction is composed of hard segments of the polyurethane structure.

If the thermoplastic polyurethane elastomer is classified according to the type of long-chain polyol used as its soft segment component, it can be divided into polyester-based polyurethane elastomer, polyether-based polyurethane elastomer, polycarbonate-based polyurethane elastomer, etc. . Among the above, the base material in this embodiment is preferably a polyether polyurethane elastomer.

As the above-mentioned long-chain polyols, specifically, polyester polyols such as lactone-based polyester polyols and adipate-based polyester polyols; polypropylene (ethylene) polyols, polytetramethylene polyols, etc. Polyether polyols such as ether glycols; polycarbonate polyols, etc. Among the above, it is better to use polyether polyol, and its number average molecular weight is usually 600-5000.

As said polyisocyanate, 2, 4- toluene diisocyanate, 2, 6-toluene diisocyanate, 4,4'- diphenylmethane diisocyanate (pure MDI), hexamethylene diisocyanate, etc. are mentioned. Among the above, it is better to use pure MDI.

Examples of the chain extender include low molecular weight polyols such as 1,4-butanediol and 1,6-hexanediol, aromatic diamines, and the like.

As an example of the above-mentioned polyester resin, in addition to the above, a polyester resin having an alicyclic structure can be cited.

Furthermore, in the case of using the adhesive sheet according to this embodiment as a dicing sheet, from the viewpoint of easily suppressing the generation of cutting chips, the alicyclic structure possessed by the polyester resin has 6 carbon atoms in the ring. The above is better. Furthermore, the number of carbon atoms is preferably 14 or less, and particularly preferably 10 or less. In particular, the number of carbon atoms described above is preferably 6. Furthermore, the alicyclic structure may be a monocyclic type composed of one ring, a bicyclic type composed of two rings, or a structure composed of three or more rings.

Furthermore, from the viewpoint that the base material in this embodiment can easily have better flexibility, the above-mentioned polyester resin contains a dicarboxylic acid having an alicyclic structure as a monomer constituting the polyester resin The unit is better. In addition, from the same viewpoint, the above-mentioned polyester resin preferably contains a diol having an alicyclic structure as a monomer unit constituting the polyester resin. The polyester resin may contain only any one of the dicarboxylic acid and the diol, and from the viewpoint of making it easier to have better flexibility, the polyester resin contains the dicarboxylic acid and the diol The two are better.

The structure of the above-mentioned dicarboxylic acid is not particularly limited as long as it has an alicyclic structure and two carboxyl groups. For example, the dicarboxylic acid may be a structure in which two carboxyl groups are bonded to an alicyclic structure, or may be a structure in which an alkyl group or the like is further inserted between the alicyclic structure and the carboxyl group. As a preferable example of this dicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,4 -Decahydronaphthalene dicarboxylic acid, 1,5-decahydronaphthalene dicarboxylic acid, 2,6-decahydronaphthalene dicarboxylic acid, 2,7-decahydronaphthalene dicarboxylic acid, etc., among the above, use 1 , 4-cyclohexanedicarboxylic acid is preferred. These dicarboxylic acids may be derivatives such as alkyl esters. Such an alkyl ester derivative may be, for example, an alkyl ester having 1 or more and 10 or less carbon atoms. As a more specific example, dimethyl ester, diethyl ester, etc. can be cited, and dimethyl ester is particularly preferred.

The structure of the above-mentioned diol is not particularly limited as long as it has an alicyclic structure and two hydroxyl groups. For example, the diol may be a structure in which two hydroxyl groups are bonded to an alicyclic structure, or may be a structure in which an alkyl group or the like is further inserted between the aforementioned alicyclic structure and the hydroxyl group. As a preferred example of this diol, 1,2-cyclohexanediol (especially 1,2-cyclohexanedimethanol), 1,3-cyclohexanediol (especially 1,3 -Cyclohexanedimethanol), 1,4-cyclohexanediol (especially 1,4-cyclohexanedimethanol), 2,2-bis-(4-hydroxycyclohexyl)-propane, etc., among the above Among them, 1,4-cyclohexanedimethanol is preferably used.

From the viewpoint that the base material becomes easy to have the desired flexibility and to achieve more excellent extensibility, the above-mentioned polyester resin contains a dimer acid obtained by dimerizing an unsaturated fatty acid as a constituent of the polymer resin. The monomer unit of the ester resin is preferred. Here, the number of carbon atoms of the unsaturated fatty acid is preferably 10 or more, and particularly preferably 15 or more. Furthermore, the number of carbon atoms is preferably 30 or less, and particularly preferably 25 or less. Examples of such dimer acids include dimerization of unsaturated fatty acids with 18 carbon atoms, such as oleic acid and linoleic acid, to obtain dicarboxylic acids with 36 carbon atoms and erucic acid. Dicarboxylic acid with 44 carbon atoms and the like obtained by dimerization of unsaturated fatty acids with 22 carbon atoms. In addition, when the dimer acid is obtained, the trimer acid obtained by subjecting the unsaturated fatty acid to the trimerization reaction may sometimes be produced in a small amount. The polyester resin may also contain the dimer acid and the trimer acid.

The said polyester resin may contain monomers other than the said dicarboxylic acid, a diol, and a dimer acid as a monomer unit which comprises this polyester resin. Examples of such monomers include aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid; phthalic acid, Aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, etc. Furthermore, a diol component other than the diol having an alicyclic structure may be included. For example, it may also contain ethylene glycol, propylene glycol, butylene glycol, hexanediol, octanediol, decanediol; ethylene oxide adducts such as bisphenol A and bisphenol S; trimethylolpropane, etc. .

Furthermore, the heat of fusion measured on the polyester resin using differential scanning calorimetry at a heating rate of 20°C/min is preferably 2J/g or more, preferably 5J/g or more, and 10J/g g or more is particularly preferable, and 15J/g or more is more preferable. Since the heat of fusion is 2 J/g or more, the crystallinity of the substrate in this embodiment is appropriately improved, and the substrate has better handleability and processability. Furthermore, the heat of fusion is preferably 150 J/g or less, preferably 100 J/g or less, particularly preferably 70 J/g or less, more preferably 50 J/g or less, and particularly preferably 30 J/g or less . Since the heat of fusion is 150 J/g or less, the base material in this embodiment can easily have more excellent flexibility.

In addition, the above-mentioned heat of fusion can be measured using a differential scanning calorimeter (for example, DSC manufactured by TA Instruments, product name "DSC Q2000") in accordance with JIS K 7121:2012.

From the standpoint of easily achieving desired stretch properties, the film containing the polyester resin as a main material described above also preferably contains the polyester resin as well as the elastomer. The elastomer is not particularly limited, and may be a thermosetting elastomer or a thermoplastic elastomer. From the viewpoint that the substrate in this embodiment is likely to have more excellent flexibility, a thermoplastic elastomer is preferred .

Examples of the above-mentioned thermoplastic elastomer are also not particularly limited. For example, styrene-based elastomers, olefin-based elastomers, polyester-based elastomers, silicone-based elastomers, etc. can be used. The above-mentioned materials may be used alone or in combination of two or more kinds. Among the above-mentioned elastomers, it is preferable to use a styrene-based elastomer from the viewpoint of easily having more excellent flexibility.

Examples of the above-mentioned styrene elastomer include styrene/conjugated diene copolymers and styrene/olefin copolymers. Specific examples of styrene and conjugated diene copolymers include styrene and butadiene copolymers, styrene, butadiene, and styrene copolymers (SBS), styrene, butadiene, and butene・Unhydrogenated styrene copolymer, styrene/isoprene copolymer, styrene, isoprene, styrene copolymer (SIS), styrene, ethylene, isoprene, styrene copolymer, etc. Styrene and conjugated diene copolymers; styrene, ethylene/propylene, styrene copolymer (SEPS), styrene, ethylene/butene, styrene copolymer (SEBS), etc. Olefin copolymer and so on. The above-mentioned materials may be used alone or in combination of two or more kinds. Among the above-mentioned styrene elastomers, from the standpoint of easily achieving better flexibility, styrene/conjugated diene copolymers are preferred, and among them, hydrogenated styrene/conjugated diene copolymers are preferred. It is better, and it is more preferable to use a styrene·ethylene/butene·styrene copolymer.

From the viewpoint that the environmental load can be further reduced, the base material in this embodiment also preferably does not contain halogen atoms. As the halogen atom, in addition to the aforementioned chlorine atom, a fluorine atom, a bromine atom, an iodine atom, and the like can be cited. In addition, as in the case of the aforementioned chlorine atom, the term "not containing a halogen atom" herein may also mean that the halogen atom is not substantially contained. In this case, the content of the halogen atom in the base material may be 0.005% by mass or less, particularly 0.003% by mass or less, and further may be 0.0001% by mass or less.

In addition, additives such as flame retardants, plasticizers, lubricants, antioxidants, colorants, infrared absorbers, ultraviolet absorbers, and ion scavengers may be added to the substrate in this embodiment. The content of these additives is not particularly limited, but is preferably within a range that allows the substrate to perform the desired function.

The layer structure of the substrate in this embodiment may be a single layer, or may be a plurality of layers. Furthermore, in order to improve the adhesion with the adhesive layer, surface treatments such as primer treatment, corona treatment, plasma treatment, etc. may be applied to the surface of the substrate on which the adhesive layer is to be laminated.

(1-3) Preparation method of base material The manufacturing method of the base material in this embodiment is not particularly limited. For example, melt extrusion molding methods such as T-die method and round die method; calender molding method; solution methods such as dry method and wet method can be used. Wait. Among the above, from the viewpoint that the base material can be efficiently manufactured, it is preferable to adopt a melt extrusion molding method or a calender molding method.

In the case of manufacturing a substrate composed of a single layer by a melt extrusion molding method, the materials of the substrate can be uniformly mixed, and the resulting mixture can be directly or once manufactured into pellets using a known extrusion method. Take out the forming machine to make the film. Furthermore, in the case of using a melt extrusion molding method to produce a substrate composed of multiple layers, the components constituting each layer can be uniformly mixed, and the resulting mixture can be directly or once manufactured into pellets. Using a well-known extrusion molding machine, multiple layers are simultaneously extruded to form a film.

(1-4) The thickness of the base material The thickness of the substrate in this embodiment is preferably 20 μm or more, particularly preferably 40 μm or more, and more preferably 60 μm or more. Furthermore, the thickness of the substrate is preferably 600 μm or less, particularly preferably 300 μm or less, and more preferably 200 μm or less. Since the thickness of the base material is 20 μm or more, the adhesive sheet becomes easy to have appropriate strength, and it becomes easy to well support the workpiece fixed on the adhesive sheet. As a result, it becomes possible to effectively suppress the occurrence of chipping and the like at the time of cutting. Furthermore, since the thickness of the substrate is 600 μm or less, it becomes easy to satisfy the aforementioned physical properties regarding the tensile stress from the time of elongation to 100% of elongation and the tensile stress from the time of 100% elongation to 200% of elongation. In addition, since the thickness of the base film is 600 μm or less, the base film has better processability.

(2) Adhesive layer The adhesive constituting the adhesive layer of the present embodiment is not particularly limited as long as it can express sufficient adhesion to the adherend (in particular, sufficient adhesion to the workpiece for processing the workpiece). Examples of adhesives constituting the adhesive layer include acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, polyester adhesives, and polyvinyl ether adhesives.剂 etc. Among the above, it is preferable to use an acrylic adhesive from the viewpoint of easy development of the desired adhesive force.

The adhesive that constitutes the adhesive layer in this embodiment may be an adhesive that does not have active energy ray hardenability, but an adhesive that has active energy ray hardenability (hereinafter sometimes referred to as "active energy ray hardenability"). Adhesive”) is better. Since the adhesive layer is composed of an active energy ray-curable adhesive, the adhesive layer can be hardened by irradiating the active energy ray, and the adhesive force of the adhesive sheet to the adherend is easily reduced. In particular, when the adhesive sheet according to the present embodiment is used as a sheet for workpiece processing, by irradiating active energy rays, it becomes easy to separate the processed workpiece from the adhesive sheet.

As the active energy ray curable adhesive constituting the adhesive layer, a polymer having active energy ray curability can be used as the main component, or it can also be composed of an active energy ray non-curable polymer (non-active energy ray curable polymer). Polymer) and a mixture of monomers and/or oligomers having at least one active energy ray-curable group as main components.

The active energy ray-curable polymer is a (meth)acrylate polymer in which an active energy ray-curable functional group (active energy ray-curable group) is introduced into the side chain (hereinafter sometimes referred to as "active energy ray-curable group). Energy ray curable polymer") is preferred. This active energy ray-curable polymer is a polymerization obtained by reacting an acrylic copolymer having a functional group-containing monomer unit and an unsaturated group-containing compound having a functional group capable of bonding with the above-mentioned functional group Good things. In addition, in this specification, the (meth)acrylic type means both acrylic acid and methacrylic acid. The same goes for other similar terms. Furthermore, "polymer" also includes the concept of "copolymer".

The weight average molecular weight of the active energy ray-curable polymer is preferably 10,000 or more, particularly preferably 150,000 or more, and more preferably 200,000 or more. Furthermore, the weight average molecular weight is preferably 2.5 million or less, particularly preferably 2 million or less, and more preferably 1.5 million or less. In addition, the weight average molecular weight (Mw) in this specification is a value converted from standard polystyrene measured by gel permeation chromatography (GPC).

On the other hand, the active energy ray hardening adhesive includes a mixture of active energy ray non-hardening polymers and monomers and/or oligomers having at least one active energy ray hardening group as main components. In this case, as the active energy ray non-curable polymer component, for example, the above-mentioned acrylic copolymer before reacting the unsaturated group-containing compound can be used. In addition, as active energy ray-curable monomers and/or oligomers, for example, esters of polyols and (meth)acrylic acid can be used.

The weight average molecular weight of the acrylic polymer as the active energy ray non-curable polymer component is preferably 10,000 or more, particularly preferably 150,000 or more, and more preferably 200,000 or more. Furthermore, the weight average molecular weight is preferably 2.5 million or less, particularly preferably 2 million or less, and more preferably 1.5 million or less.

In addition, when ultraviolet rays are used as the active energy rays for curing the active energy ray-curable adhesive, it is preferable to add a photopolymerization initiator to the adhesive. Furthermore, an active energy ray non-curable polymer component and an oligomer component, or a crosslinking agent may be added to the adhesive.

The thickness of the adhesive layer in this embodiment is preferably 1 μm or more, particularly preferably 2 μm or more, and more preferably 3 μm or more. Furthermore, the thickness of the adhesive layer is preferably 50 μm or less, particularly preferably 40 μm or less, and more preferably 30 μm or less. Since the thickness of the adhesive layer is 1 μm or more, the adhesive sheet according to this embodiment can easily exhibit the desired adhesiveness. Furthermore, since the thickness of the adhesive layer is 50 μm or less, when the adherend is separated from the cured adhesive layer, it becomes easy to separate.

(3) Peeling sheet In the adhesive sheet according to this embodiment, before attaching the surface of the adhesive layer opposite to the substrate (hereinafter sometimes referred to as "adhesive surface") to the adherend, the surface may be protected A release sheet is laminated on this surface.

The above-mentioned release sheet may have any structure, for example, a structure in which a plastic film is peeled off with a release agent or the like. As specific examples of the plastic film, polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate can be cited; as well as polypropylene and poly Polyolefin films such as ethylene. As the above-mentioned release agent, silicones, fluorines, long-chain alkyls, etc. can be used. Among the above, silicones that are inexpensive and can obtain stable performance are preferred.

The thickness of the release sheet is not particularly limited, and may be, for example, 20 μm or more and 250 μm or less.

(4) Other In the pressure-sensitive adhesive sheet according to this embodiment, the adhesive layer may be laminated on the surface of the pressure-sensitive adhesive layer on the side opposite to the substrate. In this case, the adhesive sheet according to this embodiment can be used as a dicing/die bonding sheet. In this sheet, the workpiece can be attached to the surface of the adhesive layer on the opposite side of the adhesive layer, and the adhesive layer can be cut together with the workpiece to obtain a wafer laminated with a singular adhesive layer . The chip can be easily fixed to the object on which the chip is mounted by the thus singulated adhesive layer. As a material constituting the adhesive layer, it is preferable to use a material containing a thermoplastic resin and a low molecular weight thermosetting adhesive component, or a material containing a B-stage (semi-cured) thermosetting adhesive component, or the like.

Furthermore, in the adhesive sheet according to this embodiment, a protective film forming layer may be laminated on the adhesive surface of the adhesive layer. In this case, the adhesive sheet according to this embodiment can be used as a protective film formation and dicing sheet. In this sheet, the workpiece can be attached to the surface of the protective film forming layer on the opposite side of the adhesive layer, and the protective film forming layer can be cut together with the workpiece to obtain a laminated protective film. Layered wafers. As the workpiece, it is preferable to use a workpiece with a circuit formed on one surface. In this case, a protective film forming layer is usually laminated on the surface opposite to the surface on which the circuit is formed. The singulated protective film forming layer can be cured in a predetermined time, and a protective film having sufficient durability can be formed on the wafer. The protective film forming layer is preferably composed of an uncured curable adhesive.

2. Manufacturing method of adhesive sheet The manufacturing method of the pressure-sensitive adhesive sheet according to this embodiment is not particularly limited. For example, it is preferable to obtain an adhesive sheet by forming an adhesive layer on the release sheet and then layer an area of the base material on the surface of the adhesive layer on the opposite side of the release sheet.

The above-mentioned adhesive layer can be formed by a well-known method. For example, a coating liquid containing an adhesive composition for forming an adhesive layer, and a solvent or dispersion medium to be further added as required is prepared. Then, the above-mentioned coating liquid is applied to the releasable surface of the release sheet (hereinafter may be referred to as a “release surface”). Next, the obtained coating film can be dried to form an adhesive layer.

The above-mentioned coating liquid can be applied by a known method, for example, a bar coating method, a knife coating method, a roll coating method, a blade coating method, Die coating (die coating) method, gravure coating (gravure coating) method, etc. are performed. In addition, the properties of the coating liquid are not particularly limited as long as it can be applied. If it contains a component for forming an adhesive layer as a solute, it may also contain it as a dispersion medium. Furthermore, the release sheet can be used as a process material to peel off, or it can be used to protect the adhesive layer until it is attached to the adherend.

In the case where the adhesive composition for forming the adhesive layer contains the aforementioned crosslinking agent, by changing the above-mentioned drying conditions (temperature, time, etc.), or by additionally performing heat treatment, the polymerization in the coating film The material component and the cross-linking agent produce a cross-linking reaction, and it is better to form a cross-linked structure with a desired density in the adhesive layer. In addition, in order to fully advance the above-mentioned crosslinking reaction, after bonding the adhesive layer and the base material, for example, it may be allowed to stand for several days in an environment at 23° C. and a relative humidity of 50% for curing.

3. How to use the adhesive sheet The adhesive sheet according to this embodiment can be used for various applications like general adhesive sheets, but is particularly suitable for use as a workpiece processing sheet used for processing workpieces such as semiconductor wafers. In this case, after attaching the adhesive surface of the adhesive sheet according to this embodiment to the workpiece, the workpiece can be processed on the adhesive sheet. The pressure-sensitive adhesive sheet according to the present embodiment can be used as a wafer processing sheet such as a crystal back polishing sheet, a dicing sheet, an expansion sheet, and a pick-up sheet, depending on the processing. Here, as examples of the workpiece, semiconductor components such as semiconductor wafers and semiconductor packages, and glass components such as glass plates can be cited.

As mentioned above, the adhesive sheet according to this embodiment can be expanded well. Therefore, among the above-mentioned workpiece processing sheets, the adhesive sheet according to this embodiment is particularly suitable for use as a sheet that can be expanded (a dicing sheet, an expansion sheet, a pickup sheet, etc.).

In addition, when the adhesive sheet according to this embodiment includes the aforementioned adhesive layer, the adhesive sheet can be used as a dicing/die bonding sheet. In addition, when the pressure-sensitive adhesive sheet according to the present embodiment includes the aforementioned protective film forming layer, the pressure-sensitive adhesive sheet can be used as a protective film forming and dicing sheet.

Furthermore, when the adhesive layer in the adhesive sheet according to the present embodiment is composed of the aforementioned active energy ray-curable adhesive, it is also preferable to irradiate the following active energy rays during use. That is, in the case where the processing of the workpiece is completed on the adhesive sheet and the processed workpiece is separated from the adhesive sheet, it is preferable to irradiate the adhesive layer with active energy rays before the separation. In this way, the adhesive layer is hardened, and the adhesion of the adhesive sheet to the processed workpiece is reduced well, so that the processed workpiece can be easily separated.

The embodiments described above are described for ease of understanding of the present invention, and are not described for limiting the present invention. Therefore, it means that each requirement disclosed in the above-mentioned embodiment also includes all design changes and equivalents falling within the technical scope of the present invention.

[Example] Hereinafter, the present invention will be explained more specifically through examples and the like, but the scope of the present invention is not limited to these examples and the like.

[Example 1] (1) Preparation of adhesive composition Mix 160 parts of the product name "DOWSIL SD 4580", 40 parts of the product name "DOWSIL 7646", and 1.5 parts of the product name "DOWSIL SRX 212" of various silicone resins (any product is made of Dow Toray (Dow Toray) Co., Ltd.) to obtain silicone adhesive composition.

(2) Formation of adhesive layer The silicone adhesive composition obtained above was applied to a release sheet obtained by peeling off one side of a polyethylene terephthalate film using a fluorine-based release agent (Lintec ) The peeling treatment surface manufactured by the joint stock company, the product name is "SP-PET 50E-0010YC"), and the resulting coating film is dried at 100°C for 1 minute. In this way, a laminate in which an adhesive layer having a thickness of 10 μm was formed on the release surface of the release sheet was obtained.

(3) Making of adhesive sheet The side of the polytetrafluoroethylene (PTFE) sheet (manufactured by Nichias Co., Ltd., product name "Naflon PTFE tape TOMBO 9001", thickness: 100μm) as the base material is the same as in the above step (2) The surface of the adhesive layer side of the laminate obtained in the above was bonded to obtain an adhesive sheet.

[Example 2] (1) Preparation of adhesive composition Using the solution polymerization method, 95 parts by mass of n-butyl acrylate and 5 parts by mass of acrylic acid were polymerized to obtain a (meth)acrylate polymer. The weight average molecular weight (Mw) of this acrylic polymer is determined to be 500,000 by the method described later.

100 parts by mass of the (meth)acrylate polymer obtained by the above method (calculated in terms of solid content, the same applies hereinafter), and 120 parts by mass of urethane acrylate oligomer (Mw: 8,000) ), 5 parts by mass of isocyanate crosslinking agent (manufactured by Tosoh Co., Ltd., the product name is "Coronate L"), and 4 parts by mass of photopolymerization initiator (manufactured by IGM Resins BV) , The product name is "Omnirad 184") to obtain an active energy ray-curable adhesive composition.

(2) Formation of adhesive layer The adhesive composition obtained in the above step (1) is applied to the peeling process of a polyethylene terephthalate film with a thickness of 38 μm using a silicone-based release agent. The peeling surface of the sheet (manufactured by Lindek Co., Ltd., product name is "SP-PET381031"), and the resulting coating film is dried at 100°C for 1 minute. In this way, a laminate in which an adhesive layer having a thickness of 10 μm was formed on the release surface of the release sheet was obtained.

(3) Making of adhesive sheet The base material of a thermoplastic polyurethane elastomer (TPU) sheet (manufactured by BASF, product name "Elastollan 1164D", thickness: 80μm) and the laminate obtained in the above step (2) The surface on the side of the middle adhesive layer is laminated to obtain an adhesive sheet.

Here, the aforementioned weight average molecular weight (Mw) is a weight average molecular weight in terms of standard polystyrene measured (GPC measurement) using gel permeation chromatography (GPC) under the following conditions. <Measurement conditions> ・Measuring device: HLC-8320 manufactured by Tosoh Corporation ・GPC column (pass in the following order): manufactured by Tosoh Corporation TSK gel super H-H TSK gel super HM-H TSK gel super H2000 ・Measurement solvent: tetrahydrofuran (tetrahydrofuran) ・Measurement temperature: 40°C

[Example 3] In a reactor equipped with a stirrer, a distillation tube and a decompression device, add 12.90kg of 1,4-cyclohexanedicarboxylate (the ratio of trans isomer is 98%), 11.47kg of 1 , 4-cyclohexanedimethanol, 0.3 kg of ethylene glycol, and 0.11 kg of ethylene glycol solution containing 10% manganese acetate tetrahydrate, and heated to 200 ℃ under a nitrogen stream, the temperature was changed within 1 hour Raised to 230°C. After leaving it to stand for 2 hours for transesterification reaction, 10.30 kg of erucic acid-derived dimer acid (44 carbon atoms, manufactured by Croda, product name "PRIPOL1004"), 0.11 kg containing 10 The ethylene glycol solution of% trimethyl phosphate was added to the reaction system, followed by an esterification reaction at 230°C for 1 hour. Next, 300 ppm of germanium dioxide was added as a polycondensation catalyst and stirred, and the pressure was reduced to 133 Pa or less within 1 hour. During this time, the internal temperature was increased from 230°C to 270°C and stirred until the high vacuum was below 133 Pa The viscosity is lowered to a predetermined viscosity for the polycondensation reaction to proceed. The obtained polymer is extruded into strands in water and cut into pellets.

After the pellets of the polyester resin (PEs) obtained in the above manner were dried at 85° C. for 4 hours or more, they were put into a hopper of a single screw extruder equipped with a T-die. Then, under the conditions of a cylinder temperature of 220°C and a mold temperature of 220°C, the above resin was extruded from the T-die in a melt-kneaded state, and cooled by a cooling roll to obtain a thickness of 80μm. The sheet-like substrate. The adhesive sheet was obtained in the same manner as in Example 2 except that the substrate was used.

In addition, the above-mentioned polyester resin contains about 50 mol% of 1,4-cyclohexane dimethanol, about 40.5 mol% of dimethyl 1,4-cyclohexane dicarboxylic acid, and 9.5 mol% of mustard. The acid-derived dimer acid serves as the monomer constituting the resin. Furthermore, the ratio of the dimer acid to all the dicarboxylic acid units constituting the polyester resin was 19.1 mol%.

In addition, according to JIS K 7121:2012, the heat of fusion of the polyester resin measured using a differential scanning calorimeter (DSC manufactured by TA Instruments, product name "DSC Q2000") was 20 J/g. In this measurement step, first, heat from normal temperature to 250°C at a temperature increase rate of 20°C/min, maintain at 250°C for 10 minutes, and lower the temperature to -60°C at a temperature decrease rate of 20°C/min, and Maintain at 60°C for 10 minutes. Then, it was heated again to 250°C at a heating rate of 20°C/min to obtain a DSC curve, and the melting point was measured.

[Example 4] In the same manner as in Example 3, pellets of polyester resin (PEs) were obtained. Then, the pellets were dried at 85°C for 4 hours or more. Then, using a twin-screw kneader, 70 parts by mass of the dried pellets and 30 parts by mass of styrene·ethylene/butylene·styrene copolymer (SBES) (styrene /Ethylene·Butene ratio = 20/80, Melt Flow Rate (MFR) = 13.0g/10min (measured in accordance with ISO1133 at 230°C and a load of 2.16 kg)) for mixing. The pellets thus obtained are put into the hopper of a single screw extruder equipped with a T-die. Then, under the conditions of a cylinder temperature of 220°C and a mold temperature of 220°C, the pellets were extruded from the T-die in a melt-kneaded state, and cooled by a cooling roll to obtain a thickness of 80μm sheet-like substrate. The adhesive sheet was obtained in the same manner as in Example 2 except that the substrate was used.

[Comparative Example 1] The adhesive sheet was obtained in the same manner as in Example 2 except that a substrate (thickness: 80 μm) composed of ethylene-methacrylic acid copolymer (EMAA) was used as the substrate.

[Comparative Example 2] In addition to using a substrate (thickness: 80 μm) composed of EMAA and having one surface treated with electron beam irradiation (EB) as the substrate, an adhesive layer is laminated on the surface of the substrate subjected to electron beam irradiation, Otherwise, an adhesive sheet was obtained in the same manner as in Example 2.

[Test Example 1] (Measurement of the tensile properties of the base material) For the substrates produced in the Examples and Comparative Examples, any one of the plane viewing angles is used as the reference direction, and the angle formed between the reference direction and the plane viewing angle is defined as 0°, 10°, 20° °, 30°, 40°, 50°, 60°, 70°, 80°, 90°, 100°, 110°, 120°, 130°, 140°, 150°, 160° and 170°A total of 18 directions .

Next, by cutting the above-mentioned base material, 18 kinds of test pieces (15 mm×150 mm) were obtained. When performing this cutting, each test piece was cut so that its long side was parallel to one of the above-mentioned 18 directions.

For these test pieces, in accordance with JIS K7127: 1999, using a tensile testing machine (manufactured by Shimadzu Corporation, the product name is "Autograph AG-Xplus 100N"), the distance between the chucks is set to 100mm, and the temperature is at 23°C. Under the environment, at a speed of 200mm/min, perform a tensile test of the tensile test piece in the longitudinal direction.

Next, the increase in tensile stress obtained by subtracting the tensile stress at 200% elongation by the tensile stress at 100% elongation was calculated from the results of the above-mentioned test. Then, for the test piece with the smallest amount of increase, the direction parallel to the long side of the test piece (one of the aforementioned 18 directions) is defined as the first measurement direction. Furthermore, the direction whose angle formed by the plane viewing angle with the first measurement direction is 90° is defined as the second measurement direction. In addition, the second measurement direction is substantially parallel to the MD direction of the substrate (the transport direction when the substrate is manufactured), and the first measurement direction is substantially parallel to the TD direction of the substrate (the direction perpendicular to the MD direction). .

Then, the base materials produced in the examples and comparative examples were cut again so that the long sides were parallel to the first measurement direction to obtain a test piece with a size of 15 mm×150 mm. According to JIS K7127: 1999, the tensile modulus and elongation at break were measured for this test piece. Specifically, using a tensile testing machine (manufactured by Shimadzu Corporation, with the product name "Autograph AG-Xplus 100N") on the above-mentioned test piece, the distance between the chucks is set to 100 mm, and then in an environment of 23°C, At a speed of 200 mm/min, a tensile test of the tensile test piece in the first measurement direction of the base film is performed to measure the tensile modulus (MPa) and the elongation at break (%). These results are shown in Table 1 as the tensile modulus of elasticity and the elongation at break according to the first measurement direction.

Furthermore, for the test piece obtained in the same manner as described above, a tensile test was performed to stretch the test piece in the first measurement direction of the base film at a speed of 200 mm/min in an environment of 23° C. to The change in tensile stress (MPa) when the tensile elongation (%) is increased from 0% to 250% is measured.

Then, the tensile stress (MPa) at the time points at which the tensile elongation was 10%, 50%, 100%, 150%, 200%, and 250% was recorded. In addition, the increase in tensile stress (MPa) and the time when the tensile elongation increased from 100% to 200% were calculated respectively. The increase in tensile stress (MPa). Furthermore, the ratio of the tensile stress at the time when the tensile elongation was 200% to the tensile stress at the time when the tensile elongation was 100% was calculated. These results are also shown in Table 1 as measured values of each stretched physical property according to the first measurement direction.

In addition, for the tensile stress (MPa) measured as described above, the measurement result is plotted on the horizontal axis with the tensile elongation (unit: %) and the tensile stress (unit: MPa) as the vertical axis. On the coordinate plane, to make a curve. It was confirmed whether there is a maximum point where the tensile stress becomes a maximum value in the curve. The results are shown in Table 1. In addition, in the case of the existence of this maximum point, it is further confirmed whether there is a minimum point where the tensile stress becomes a minimum value, and then the maximum point is determined (if there are more than one point, it is the minimum value of the tensile elongation The absolute value (MPa) of the difference in tensile stress between the maximum point) and the minimum point (in the case of multiple points, which is the minimum point where the value of the tensile elongation is the smallest). The results are also shown in Table 1.

Furthermore, in the same manner as the method of obtaining the test piece described above, a test piece for measuring the tensile properties according to the second measurement direction was obtained. That is, by cutting the side of 150 mm so as to be parallel to the second measurement direction of the base material, a test piece of 15 mm×150 mm was cut out.

For the test piece thus obtained, while measuring the tensile elastic modulus (MPa) in the same manner as above, the tensile stress ( MPa) change. Then, determine the tensile stress (MPa) at 10%, 50%, 100%, 150%, 200%, and 250% from the change in tensile stress (MPa), and further calculate the increase from the above value Increase in tensile stress (MPa). Calculate from 10% time point to 200% time point, from 50% time point to 150% time point, from 50% time point to 250% time point, and from 100% time point to 200 % Of the four time points, as the increase. These results are also shown in Table 2 as measured values of each stretched physical property according to the second measurement direction.

[Test Example 2] (Evaluation of scalability) The peeling sheet was peeled from the adhesive sheets manufactured in the examples and comparative examples, and after the exposed surface of the adhesive layer thus exposed was attached to one side of a silicon wafer with a thickness of 40 μm, the ring frame for dicing was applied Attached to the peripheral part of the exposed surface of the adhesive sheet (a position that does not overlap with the silicon wafer). Then, using a dicing machine (manufactured by Disco Co., Ltd., product name "DFD6362"), the silicon wafer was diced under the following conditions. ・Workpiece (adhesive): silicon wafer ・Workpiece size: Diameter is 6 inches, thickness is 40μm ・Cutting knife: A diamond knife manufactured by Disco Co., Ltd., with the product name "27HECC" ・Blade speed: 50,000 rpm ・Scribing speed: 100mm/sec ・Cutting depth: Cut from the surface of the base film to a depth of 20μm ・Cutting size: 8mmx8mm

Then, the adhesive sheet to which the chip obtained by dicing and the ring frame are attached is set in the expansion device (manufactured by JCM Co., Ltd., the product name is "ME-300B"), and the ring frame is set at 2mm/sec Pull down at a speed of 40mm until the amount of pull down becomes 40mm.

Next, the amount of pull (mm) when the fracture occurred was recorded. Then, the scalability is evaluated based on the following criteria. The results are shown in Table 1 and Table 2 (the results shown in Table 1 and Table 2 are the same). A: The pull-down amount (mm) is 40mm or more. F: The pull-down amount (mm) is less than 40mm.

[Table 1]

[Table 2]

It is clear from Tables 1 and 2 that the adhesive sheets manufactured in the examples exhibited excellent expandability. [Industrial Profitability]

The adhesive sheet of the present invention can be applied to a workpiece processing sheet used in the processing of a workpiece such as a semiconductor wafer.

none.

[Fig. 1] A curve for explaining the physical properties of the substrate in this embodiment is drawn.

Claims (10)

An adhesive sheet comprising a base material and an adhesive layer laminated on one surface side of the base material, wherein the base material does not contain chlorine atoms and is in any direction from the plane viewing angle of the base material As the reference direction, the angle formed between the aforementioned reference direction and the plane viewing angle is 0°, 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, 90°, 100° , 110°, 120°, 130°, 140°, 150°, 160° and 170° in 18 directions, the tensile stress at 200% elongation is subtracted from the tensile stress at 100% elongation When the direction with the smallest increase in tensile stress is set as the first measurement direction, for the aforementioned substrate, in the aforementioned first measurement direction, the tensile stresses from 10% elongation to 100% elongation are all between Within the range of 8 MPa or more and 30 MPa or less, and for the aforementioned substrate, in the aforementioned first measurement direction, the tensile stresses from 100% elongation to 200% elongation are all within the range of 10 MPa or more and 40 MPa or less. The pressure-sensitive adhesive sheet according to claim 1, wherein for the aforementioned substrate, the tensile stress obtained by subtracting the tensile stress at 100% elongation from the tensile stress at 100% elongation in the aforementioned first measurement direction The increase is 1 MPa or more and 20 MPa or less. The pressure-sensitive adhesive sheet according to claim 1, wherein the direction in which the angle formed between the first measurement direction and the first measurement direction is one direction of the plane viewing angle of the substrate is set as the second measurement direction, For the aforementioned substrate, in the aforementioned second measurement direction, the tensile stress from 10% elongation to 100% elongation is all within the range of 5 MPa or more and 30 MPa or less. In the measurement direction, the tensile stresses from 100% elongation to 200% elongation are all within the range of 10 MPa or more and 40 MPa or less. The pressure-sensitive adhesive sheet according to claim 3, wherein for the aforementioned substrate, the tensile stress obtained by subtracting the tensile stress at 100% elongation from the tensile stress at 100% elongation in the aforementioned second measurement direction The increase is 1 MPa or more and 20 MPa or less. The adhesive sheet according to claim 1, wherein the tensile elastic modulus of the base material in the first measurement direction is 100 MPa or more and 1000 MPa or less. The adhesive sheet according to claim 1, wherein the elongation at break of the base material in the first measurement direction is 100% or more and 1000% or less. The pressure-sensitive adhesive sheet according to claim 1, wherein the result measured in the case where the tensile test of the substrate is performed in the first measurement direction is plotted with the tensile elongation (unit: %) as the horizontal A curve obtained on the coordinate plane with the tensile stress (unit: MPa) as the vertical axis. There is no point in the curve that reaches a maximum value, or there is at least one point that becomes a maximum value and one point that becomes a minimum in the curve. In addition, the value of the tensile stress at the point where the tensile elongation is the minimum among the points that become the maximum value, and the point where the tensile elongation is the minimum among the points that become the minimum value The absolute value of the difference between the aforementioned tensile stress values at the point of value is 2.0 MPa or less. The adhesive sheet according to claim 1, wherein the aforementioned base material does not contain halogen atoms. The adhesive sheet described in claim 1, which is used as a sheet for workpiece processing. The adhesive sheet according to claim 9, wherein the aforementioned workpiece processing sheet is a dicing sheet.

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