JP2024052110A - Adhesive tape for semiconductor processing - Google Patents

Abstract

To provide an adhesive tape for semiconductor processing with excellent flexibility and tear resistance.SOLUTION: An adhesive tape 10 for semiconductor processing has a base material 1 and an energy ray curable adhesive layer 2 disposed on one side of the base material, the tensile strength of the adhesive tape for semiconductor processing at 40% elongation is 200 N/45 mm or less, the puncture strength after energy ray irradiation and 40% elongation is 7.2 N or more, and the adhesive strength to the SUS plate after energy beam irradiation is 1.4 N/25 mm or less.SELECTED DRAWING: Figure 1

Description

This disclosure relates to adhesive tapes for semiconductor processing.

In the semiconductor manufacturing process, an adhesive tape for semiconductor processing called dicing tape is used to protect and secure the wafer and chips during the dicing process, in which the wafer is cut (diced) into chips.

Adhesive tapes for semiconductor processing are required to have sufficient adhesive strength to hold wafers and chips in place during the processing process, and to be able to be easily peeled off after the processing process without damaging the chips.

As such adhesive tapes for semiconductor processing, adhesive tapes that have a certain adhesive strength during the processing step and whose adhesive strength can decrease after the processing step are known.

For example, Patent Documents 1 and 2 disclose energy ray curable adhesive tapes. The adhesive strength of energy ray curable adhesive tapes can be reduced by curing the adhesive layer through irradiation with energy rays, but the adhesive tape can firmly fix wafers or chips during the processing steps prior to the energy ray irradiation.

For example, Patent Document 3 discloses an adhesive tape having a gas generation layer. In the adhesive tape having a gas generation layer, gas is generated locally in a small area by irradiation with laser light, and the adhesive layer is deformed due to this gas generation, resulting in peelability in the area irradiated with the laser light.

Patent No. 6301987 International Publication No. 2019/155970 Patent No. 6890216

In a semiconductor manufacturing method using an energy beam curable adhesive tape for semiconductor processing, for example, the adhesive tape for semiconductor processing is affixed to a ring frame, and a wafer is fixed onto the adhesive tape for semiconductor processing. Next, a dicing process is performed in which the wafer is cut (diced) into chips. After that, an expanding process is performed in which the adhesive tape for semiconductor processing is stretched to increase the spacing between the chips. Next, the energy beam curable adhesive layer of the adhesive tape for semiconductor processing is irradiated with energy beams to harden it, thereby reducing the adhesive strength, and the chip is peeled off from the adhesive tape for semiconductor processing, and a pick-up process is performed in which the chip is picked up.

In recent years, as wafers and substrates, which are adherends, have become thinner, adhesive tapes for semiconductor processing are required to have high flexibility so that they can expand with a small load. However, if the flexibility of the adhesive tape for semiconductor processing is increased, there is a problem that the adhesive tape for semiconductor processing may tear during the expansion process and pick-up process. Therefore, there is a demand for adhesive tapes for semiconductor processing that are highly flexible and tear-resistant.

This disclosure was made in consideration of the above-mentioned circumstances, and its main objective is to provide an adhesive tape for semiconductor processing that is highly flexible and resistant to tearing.

One embodiment of the present disclosure provides an adhesive tape for semiconductor processing having a substrate and an energy ray-curable adhesive layer disposed on one side of the substrate, the adhesive tape having a tensile strength of 200 N/45 mm or less at 40% elongation, a puncture strength of 7.2 N or more after energy ray irradiation and 40% elongation, and an adhesive strength to a SUS plate of 1.4 N/25 mm or less after energy ray irradiation.

The adhesive tape for semiconductor processing disclosed herein has the advantage of being highly flexible and tear-resistant.

1 is a schematic cross-sectional view showing an example of an adhesive tape for semiconductor processing according to the present disclosure. 1A to 1C are process diagrams illustrating a semiconductor manufacturing method. FIG. 4 is a process diagram showing an example of a pick-up process.

Below, an embodiment of the present disclosure will be described with reference to the drawings. However, the present disclosure can be implemented in many different forms, and should not be interpreted as being limited to the description of the embodiment exemplified below. In addition, in order to make the explanation clearer, the drawings may show the width, thickness, shape, etc. of each part in a schematic manner compared to the actual form, but these are merely examples and do not limit the interpretation of the present disclosure. In this specification and each figure, elements similar to those described above with respect to the previous figures are given the same reference numerals, and detailed explanations may be omitted as appropriate.

In this specification, when describing a mode in which another component is placed on a certain component, the term "above" or "below" includes both cases in which another component is placed directly above or below a certain component so as to be in contact with the component, and cases in which another component is placed above or below a certain component with another component in between, unless otherwise specified. Also, in this specification, when describing a mode in which another component is placed on the surface of a certain component, the term "on the surface" includes both cases in which another component is placed directly above or below a certain component so as to be in contact with the component, and cases in which another component is placed above or below a certain component with another component in between, unless otherwise specified.

The adhesive tape for semiconductor processing disclosed herein is described in detail below.

The adhesive tape for semiconductor processing disclosed herein has a substrate and an energy ray-curable adhesive layer disposed on one side of the substrate, and has a tensile strength of 200 N/45 mm or less at 40% elongation, a puncture strength of 7.2 N or more after energy ray irradiation and 40% elongation, and an adhesive strength to SUS plate of 1.4 N/25 mm or less after energy ray irradiation.

Figure 1 is a schematic cross-sectional view illustrating an example of an adhesive tape for semiconductor processing according to the present disclosure. The adhesive tape for semiconductor processing 10 in Figure 1 has a substrate 1 and an energy ray-curable adhesive layer 2 disposed on one side of the substrate 1. In the adhesive tape for semiconductor processing 10, the tensile strength at 40% elongation is equal to or less than a predetermined value, the puncture strength after irradiation with energy rays and after elongation with 40% is equal to or more than a predetermined value, and the adhesive strength to a SUS plate after irradiation with energy rays is equal to or less than a predetermined value.

2(a) to (e) are process diagrams showing an example of a semiconductor manufacturing method using a semiconductor processing adhesive tape. First, as shown in FIG. 2(a), the semiconductor processing adhesive tape 10 is attached to a ring frame 21, and the wafer 11 is attached to the semiconductor processing adhesive tape 10. Next, as shown in FIG. 2(b), a dicing process is performed in which the wafer 11 is cut (diced) into chips 12. Next, as shown in FIG. 2(c), an expanding process is performed in which the semiconductor processing adhesive tape 10 is stretched to widen the gap between the chips 12. Next, although not shown, the energy ray curable adhesive layer of the semiconductor processing adhesive tape 10 is irradiated with energy rays to harden it, thereby reducing the adhesive force, and as shown in FIG. 2(d), a pick-up process is performed in which the chip 12 is peeled off from the semiconductor processing adhesive tape 10 and picked up. Next, as shown in FIG. 2(e), a mounting (die bonding) process is performed in which the picked-up chip 12 is bonded to a substrate 30.

The adhesive tape for semiconductor processing disclosed herein has a tensile strength at 40% elongation before energy beam irradiation that is equal to or less than a predetermined value, and has high flexibility. Therefore, for example, in the expansion process shown in FIG. 2(c), the adhesive tape for semiconductor processing can be easily stretched with a small force, thereby reducing the load on the chip.

Here, the adhesive tape for semiconductor processing, which has excellent flexibility, is prone to tearing during the expanding process and the pick-up process. In particular, during the pick-up process, the adhesive tape for semiconductor processing may be subjected to localized stress, which may cause the adhesive tape for semiconductor processing to tear. For example, during the pick-up process, chips are usually picked up one by one. At this time, the adhesive tape for semiconductor processing may be subjected to localized stress in the area where the chip is peeled off, which may cause the adhesive tape for semiconductor processing to tear.

For example, in the pick-up process, as shown in Fig. 3(a) and Fig. 3(b), the needle 50 may push up the chip 12 from the substrate 1 side of the semiconductor processing adhesive tape 10, and the chip 12 may be peeled off from the semiconductor processing adhesive tape 10. In this case, the semiconductor processing adhesive tape may tear because the needle applies local stress to the semiconductor processing adhesive tape in a stretched state. Furthermore, for example, when peeling the chip from the semiconductor processing adhesive tape in the pick-up process, it is thought that the semiconductor processing adhesive tape gradually begins to peel off from the edge of the chip. At this time, the semiconductor processing adhesive tape and the chip are bonded at points instead of at a surface, and it is presumed that local stress is applied to the semiconductor processing adhesive tape. As a result, the semiconductor processing adhesive tape may tear.

In addition, for example, during the pick-up process, it is conceivable that a part of the conveying device or the pick-up device may come into contact with the adhesive tape for semiconductor processing, causing localized stress on the adhesive tape for semiconductor processing. In this case as well, the adhesive tape for semiconductor processing may tear.

The inventors of the present disclosure therefore investigated the resistance of semiconductor processing adhesive tapes to tearing caused by localized stress, focusing on puncture strength. In addition, in the energy ray curable semiconductor processing adhesive tape, in the pick-up process, as described above, the semiconductor processing adhesive tape is stretched, and then energy rays are irradiated to the semiconductor processing adhesive tape, after which chips are picked up. Therefore, they focused on the puncture strength after energy ray irradiation and stretching. They found that by setting the puncture strength after energy ray irradiation and stretching to a predetermined value or more, tearing can be suppressed even when localized stress is applied.

In other words, the adhesive tape for semiconductor processing disclosed herein has a puncture strength equal to or greater than a predetermined value after irradiation with energy rays and after elongation of 40%, so that the tape is less likely to break even if localized stress is applied during the pick-up process.

In addition, in the adhesive tape for semiconductor processing disclosed herein, the adhesive strength to the SUS plate after irradiation with energy rays is equal to or less than a predetermined value, so that the chip can be easily peeled off from the adhesive tape for semiconductor processing with a relatively weak force. Therefore, tearing during peeling in the pick-up process can be suppressed.

Therefore, the adhesive tape for semiconductor processing disclosed herein is able to achieve both high flexibility and tear resistance.

The components of the adhesive tape for semiconductor processing disclosed herein are explained below.

1. Characteristics of the adhesive tape for semiconductor processing (1) Puncture strength In the adhesive tape for semiconductor processing of the present disclosure, the puncture strength after energy ray irradiation and 40% elongation is 7.2N or more, preferably 8.0N or more, and more preferably 8.3N or more. By having the puncture strength in the above range, it is possible to suppress the breakage of the adhesive tape for semiconductor processing in the pick-up process. On the other hand, the upper limit of the puncture strength is not particularly limited as long as it is possible to satisfy the tensile strength at 40% elongation before energy ray irradiation described later, but is, for example, 40N or less, preferably 30N or less, and more preferably 25N or less. If the puncture strength after energy ray irradiation is large, the puncture strength before energy ray irradiation also tends to be large. Therefore, if the puncture strength is too large, the flexibility before energy ray irradiation may be impaired.

The puncture strength of the adhesive tape for semiconductor processing after irradiation with energy rays and stretching by 40% refers to the puncture strength in the thickness direction of the adhesive tape for semiconductor processing measured after irradiation with energy rays and stretching the adhesive tape for semiconductor processing by 40% in the MD direction.

The MD direction refers to the flow direction of the substrate during its manufacture, and the TD direction refers to the direction perpendicular to the MD direction. For example, if the adhesive tape for semiconductor processing is long or sheet-like and rectangular, the MD direction refers to the length direction of the adhesive tape for semiconductor processing, and the TD direction refers to the width direction of the adhesive tape for semiconductor processing.

Here, the puncture strength after the above-mentioned energy ray irradiation and 40% elongation can be measured in accordance with JIS Z1707 by the following method. First, prepare a test piece of semiconductor processing adhesive tape with a width of 45 mm and a length of 150 mm. Next, irradiate the substrate side of the test piece of semiconductor processing adhesive tape with energy rays to harden the adhesive layer. Next, if the semiconductor processing adhesive tape has a separator, peel the separator from the test piece of semiconductor processing adhesive tape. Next, elongate the test piece of semiconductor processing adhesive tape by 40% at a tensile speed of 100 mm/min. Next, in accordance with JIS Z1707, the adhesive layer side of the test piece of semiconductor processing adhesive tape after elongation is stuck to a puncture test jig and fixed, and a semicircular needle with a diameter of 1.0 mm and a tip radius of 0.5 mm is pierced from the substrate side at a speed of 300 mm/min, and the maximum load until the needle penetrates the test piece of semiconductor processing adhesive tape is measured. After the adhesive tape for semiconductor processing is stretched, the time until the puncture strength is measured is one minute. The puncture test is performed in an environment with a temperature of 25°C ± 5°C, a humidity of 40% RH to 60% RH, and energy rays blocked. Five test pieces are used, and the average is calculated, and this average is the puncture strength. The measurement device can be a digital force gauge "ZTS-500N" manufactured by Imada Co., Ltd. The jig for fixing the test piece can be a puncture test jig with a circular opening with a diameter of 20 mm ("TKS-250N" manufactured by Imada Co., Ltd.). The needle can be a "TP-20" manufactured by Imada Co., Ltd.

Methods for controlling the puncture strength after the above-mentioned energy ray irradiation and 40% elongation include, for example, a method for adjusting the thickness and elastic modulus of the substrate, a method for adjusting the adhesive strength after energy ray irradiation, a method for adjusting the viscoelasticity of the adhesive layer after energy ray irradiation, and a method for adjusting the breaking strength of the adhesive tape for semiconductor processing.

In the method of adjusting the thickness of the substrate, the thicker the substrate, the greater the puncture strength. In the method of adjusting the elastic modulus of the substrate, the greater the elastic modulus or Young's modulus of the substrate, the harder the adhesive tape for semiconductor processing tends to be, and the greater the puncture strength.

Methods for adjusting the adhesive strength after energy ray irradiation include a method for adjusting the components and composition contained in the adhesive layer. Specific examples of methods for adjusting the components and composition contained in the adhesive layer include a method for adjusting the content of the energy ray curable compound or the number of energy ray curable functional groups, and a method for adjusting the polarity of the adhesive base agent. For example, when the content of the energy ray curable compound and the number of energy ray curable functional groups are increased, the crosslink density of the adhesive layer after energy ray irradiation increases, the adhesive layer after energy ray irradiation tends to become harder, the adhesive strength after energy ray irradiation decreases, and the piercing strength tends to increase. Also, when the content of the energy ray curable compound and the number of energy ray curable functional groups are too high, the crosslink density of the adhesive layer after energy ray irradiation increases too much, the coating film becomes hard and brittle, and the piercing strength decreases. Also, for example, by adjusting the polarity of the adhesive base agent so that it is more compatible with the energy ray curable compound, the adhesive strength after energy ray irradiation decreases, and the piercing strength tends to increase.

Methods for adjusting the viscoelasticity of the adhesive layer after energy ray irradiation include a method for adjusting the components and composition contained in the adhesive layer, and a method for adjusting the modulus of elasticity of the adhesive layer after energy ray irradiation. Specific examples of methods for adjusting the components and composition contained in the adhesive layer include a method for adjusting the functional group equivalent of the energy ray curable compound. For example, if the functional group equivalent of the energy ray curable compound is small, the crosslink density becomes high, the adhesive layer after energy ray irradiation tends to become hard, and the puncture strength tends to increase. Also, if the functional group equivalent is too small, the crosslink density becomes too high, the coating film becomes hard and brittle, and the puncture strength decreases. Also, for example, if the modulus of elasticity of the adhesive layer after energy ray irradiation increases, the puncture strength tends to increase.

In addition, in the adhesive tape for semiconductor processing of the present disclosure, the puncture strength after 40% elongation before energy ray irradiation is, for example, 6.0 N or more, or may be 7.0 N or more, or may be 7.5 N or more. On the other hand, the puncture strength is, for example, 40 N or less, or may be 30 N or less, or may be 25 N or less. If the puncture strength is within the above range, the adhesive tape before energy ray irradiation has sufficient flexibility, and the adhesive tape is less likely to tear even after the adhesive layer is hardened by energy ray irradiation.

(2) Adhesive strength to SUS plate In the present disclosure, the adhesive strength of the energy ray curable adhesive layer is reduced by curing by irradiation with energy rays. In the semiconductor processing adhesive tape of the present disclosure, the adhesive strength to the SUS plate after energy ray irradiation is 1.4 N/25 mm or less, preferably 1.2 N/25 mm or less, and more preferably 1.0 N/25 mm or less. Since the adhesive strength to the SUS plate after energy ray irradiation is in the above range, the chip can be easily peeled off from the semiconductor processing adhesive tape after energy ray irradiation. Therefore, the stress applied to the semiconductor processing adhesive tape during peeling can be reduced, and the tearing of the semiconductor processing adhesive tape can be suppressed. On the other hand, in the semiconductor processing adhesive tape of the present disclosure, the lower limit of the adhesive strength to the SUS plate after energy ray irradiation is not particularly limited, but is, for example, 0.02 N/25 mm or more.

Here, the adhesive strength to the SUS plate after the energy beam irradiation can be measured in accordance with JIS Z0237:2009 (Test method for adhesive tapes and adhesive sheets) Test method 1 (temperature 23°C, humidity 50% RH, test method in which the tape and sheet are peeled off at 180° from the stainless steel test plate). First, the adhesive tape for semiconductor processing is attached to the SUS plate using a manual roller. Next, the adhesive layer is irradiated with energy beams to harden it. At this time, for example, the energy beam can be irradiated from the substrate side of the adhesive tape for semiconductor processing. Next, the adhesive strength to the SUS plate after the energy beam irradiation is measured by peeling off the test piece in the length direction under the conditions of a width of 25 mm, a peel angle of 180°, and a peel speed of 300 mm/min. The SUS plate can be a SUS304, surface finish BA, thickness 1.5 mm, width 100 mm, and length 150 mm.

In addition, in the semiconductor processing adhesive tape of the present disclosure, the adhesive strength to a SUS plate before irradiation with energy rays is, for example, preferably 1.0 N/25 mm or more, and more preferably 1.2 N/25 mm or more. When the adhesive strength to the SUS plate is in the above range, the wafer or divided chips can be sufficiently fixed to the semiconductor processing adhesive tape until irradiation with energy rays. On the other hand, there is no particular upper limit to the adhesive strength to the SUS plate.

Here, the adhesive strength to SUS plate can be measured in accordance with JIS Z0237:2009 (Test method for adhesive tapes and adhesive sheets), Method 1 (a test method in which the tape or sheet is peeled off at 180° from the stainless steel test plate at a temperature of 23°C and humidity of 50%) by peeling the test piece in the length direction under the conditions of a width of 25 mm, a peel angle of 180°, and a peel speed of 300 mm/min. The SUS plate to be used is a SUS304 SUS plate with a surface finish of BA, a thickness of 1.5 mm, and a size of 100 mm x 150 mm.

One way to control the adhesive strength to the SUS plate after irradiation with the energy rays is to adjust the components and composition contained in the adhesive layer.

Specific methods for adjusting the components and composition contained in the adhesive layer include adjusting the content of the energy ray curable compound or the number of energy ray curable functional groups, and adjusting the polarity of the adhesive base agent. For example, as the content of the energy ray curable compound and the number of energy ray curable functional groups increase, the crosslink density of the adhesive layer after energy ray irradiation increases, and the adhesive strength to the SUS plate after energy ray irradiation tends to decrease. Also, for example, by adjusting the polarity of the adhesive base agent so that it is more compatible with the energy ray curable compound, the adhesive strength to the SUS plate after energy ray irradiation tends to decrease.

(3) Tensile strength at 40% elongation The tensile strength at 40% elongation of the semiconductor processing adhesive tape of the present disclosure is 200N/45mm or less, preferably 150N/45mm or less, and more preferably 100N/45mm or less. By having the tensile strength at 40% elongation in the above range, the semiconductor processing adhesive tape has excellent flexibility. On the other hand, the tensile strength at 40% elongation is, for example, 15N/45mm or more, preferably 20N/45mm or more, and more preferably 25N/45mm or more. If the tensile strength at 40% elongation is too small, the flexibility may become too high, making it difficult to handle.

The tensile strength of the adhesive tape for semiconductor processing at 40% elongation is the tensile strength when the adhesive tape for semiconductor processing is elongated by 40% in the MD direction.

Here, the tensile strength at 40% elongation can be measured in accordance with JIS K7127 by the following method. First, prepare a test piece of adhesive tape for semiconductor processing, 45 mm wide and 150 mm long. Next, elongate the test piece of adhesive tape for semiconductor processing by 40% in the MD direction under the conditions of chuck distance: 50 mm, tensile speed: 100 mm/min, and measure the tensile strength at this time. A & D's "Tensilon RTF1350" can be used as the tensile tester.

Methods for controlling the tensile strength at 40% elongation include, for example, adjusting the thickness and modulus of elasticity of the substrate.

In the method of adjusting the thickness of the substrate, for example, if the thickness of the substrate is thin, the tensile strength at 40% elongation tends to be small. If the elastic modulus or Young's modulus of the substrate is small, the adhesive tape for semiconductor processing tends to be flexible, and the tensile strength at 40% elongation tends to be small. In the present disclosure, by appropriately adjusting the thickness and elastic modulus of the substrate, the puncture strength after the above-mentioned energy ray irradiation and 40% elongation, and the tensile strength at the above-mentioned 40% elongation can each be adjusted to a predetermined range.

In the adhesive tape for semiconductor processing disclosed herein, the tensile strength at 40% elongation after energy ray irradiation is not particularly limited, but may be, for example, 25 N/45 mm or more and 200 N/45 mm or less, 30 N/45 mm or more and 150 N/45 mm or less, or 35 N/45 mm or more and 100 N/45 mm or less.

(4) Stress at break In the adhesive tape for semiconductor processing of the present disclosure, the stress at break in the MD direction after energy ray irradiation is preferably 22 MPa or more and 150 MPa or less. Also, the stress at break in the TD direction after energy ray irradiation is preferably 22 MPa or more and 200 MPa or less. By being in this range, the puncture strength after the above-mentioned energy ray irradiation and 40% elongation can be easily adjusted to be within a predetermined range. Also, after energy ray irradiation, the tape has moderate flexibility.

The stress at break after energy beam irradiation can be measured by the following method in accordance with JIS K7127. First, prepare a test piece of semiconductor processing adhesive tape type 5. Next, irradiate the substrate side of the test piece of semiconductor processing adhesive tape with energy beams to harden the adhesive layer. Next, if the semiconductor processing adhesive tape has a separator, peel the separator from the test piece of semiconductor processing adhesive tape. Next, pull the test piece of semiconductor processing adhesive tape in the MD or TD direction under the conditions of chuck distance: 60 mm, tensile speed: 100 mm/min, and measure the stress at break. A & D's "Tensilon RTF1150" can be used as a tensile tester.

In the adhesive tape for semiconductor processing of the present disclosure, the stress at break in the MD direction before energy ray irradiation is preferably 15 MPa or more and 150 MPa or less. Also, the stress at break in the TD direction before energy ray irradiation is preferably 20 MPa or more and 200 MPa or less. By being in this range, the adhesive tape before energy ray irradiation has sufficient flexibility, and the adhesive tape is less likely to break even after the adhesive layer is hardened by energy ray irradiation. Note that the measured value before energy ray irradiation is a value obtained by measuring the stress at break after energy ray irradiation without irradiating energy rays.

(5) Elongation at break In the adhesive tape for semiconductor processing of the present disclosure, the elongation at break in the MD direction after energy ray irradiation is preferably 150% GL or more and 600% GL or less. In addition, the elongation at break in the TD direction after energy ray irradiation is preferably 100% GL or more and 700% GL or less. By being in this range, the puncture strength after the above-mentioned energy ray irradiation and 40% elongation can be easily adjusted to be within a predetermined range. In addition, after energy ray irradiation, the tape has moderate flexibility. The above-mentioned GL is an abbreviation of the gauge length, and this GL is the original length before deformation.

The elongation at break after irradiation with energy rays can be measured by the following method in accordance with JIS K7127. First, prepare a test piece of semiconductor processing adhesive tape of test piece type 5. Next, irradiate the substrate side of the test piece of semiconductor processing adhesive tape with energy rays to harden the adhesive layer. Next, if the semiconductor processing adhesive tape has a separator, peel the separator from the test piece of semiconductor processing adhesive tape. Next, pull the test piece of semiconductor processing adhesive tape in the MD or TD direction under the conditions of chuck distance: 60 mm, tensile speed: 100 mm/min, and measure the tensile elongation at break. A & D's "Tensilon RTF1150" can be used as a tensile tester.

In the adhesive tape for semiconductor processing of the present disclosure, the elongation at break in the MD direction before energy ray irradiation is preferably 150% GL or more and 600% GL or less. Also, the elongation at break in the TD direction before energy ray irradiation is preferably 100% GL or more and 700% GL or less. By being in this range, the adhesive tape before energy ray irradiation has sufficient flexibility, and the adhesive tape is less likely to break even after the adhesive layer is hardened by energy ray irradiation. Note that the measured value before energy ray irradiation is a value obtained by measuring the elongation at break after energy ray irradiation without irradiating energy rays.

(6) Young's modulus In the adhesive tape for semiconductor processing of the present disclosure, the Young's modulus in the MD direction after energy ray irradiation is preferably 180 MPa or more and 500 MPa or less. Also, the Young's modulus in the TD direction after energy ray irradiation is preferably 130 MPa or more and 500 MPa or less. By being in this range, the puncture strength after the above-mentioned energy ray irradiation and 40% elongation can be easily adjusted to be within a predetermined range. Also, after energy ray irradiation, the tape has moderate flexibility.

The Young's modulus of the adhesive tape for semiconductor processing after irradiation with energy rays can be measured by the following method in accordance with JIS K7127. First, prepare a test piece of the adhesive tape for semiconductor processing type 5. Next, irradiate the substrate side of the test piece of the adhesive tape for semiconductor processing with energy rays to harden the adhesive layer. Next, if the adhesive tape for semiconductor processing has a separator, peel the separator from the test piece of the adhesive tape for semiconductor processing. Next, pull the test piece of the adhesive tape for semiconductor processing in the MD or TD direction under the conditions of a chuck distance of 60 mm and a pulling speed of 100 mm/min to measure the Young's modulus. A & D's "Tensilon RTF1150" can be used as a tensile tester.

In addition, in the adhesive tape for semiconductor processing of the present disclosure, the Young's modulus in the MD direction before energy ray irradiation is preferably 100 MPa or more and 500 MPa or less. Also, the Young's modulus in the TD direction before energy ray irradiation is preferably 80 MPa or more and 500 MPa or less. By being in this range, the adhesive tape before energy ray irradiation has sufficient flexibility, and the adhesive tape is less likely to tear even after the adhesive layer is hardened by energy ray irradiation. Note that the measured value before energy ray irradiation is a value obtained by measuring the Young's modulus of the adhesive tape for semiconductor processing after energy ray irradiation without irradiating it with energy rays.

2. Substrate The substrate in the present disclosure is a member that supports the pressure-sensitive adhesive layer.

The substrate is not particularly limited, but since it is preferable to reduce the adhesive strength of the adhesive layer by irradiating the adhesive tape for semiconductor processing from the substrate side to harden the adhesive layer in the pick-up process, it is preferable that the substrate is transparent to energy rays.

The substrate may be expandable, and is preferably flexible. As described above, the puncture strength after the energy ray irradiation and 40% elongation and the tensile strength at the 40% elongation can be controlled by adjusting the Young's modulus of the substrate. For example, if the Young's modulus of the substrate is large, the puncture strength after the energy ray irradiation and 40% elongation tends to be large. On the other hand, if the Young's modulus of the substrate is small, the tensile strength at the 40% elongation tends to be small. The Young's modulus of the substrate is appropriately adjusted to satisfy the characteristics of the semiconductor processing adhesive tape. The Young's modulus of the substrate is, for example, preferably 20 MPa or more, more preferably 30 MPa or more, and even more preferably 40 MPa or more. If the Young's modulus of the substrate is within the above range, the puncture strength after the energy ray irradiation and 40% elongation can be easily adjusted to be within a predetermined range. On the other hand, the Young's modulus of the substrate is preferably 500 MPa or less, more preferably 300 MPa or less, and even more preferably 150 MPa or less. If the Young's modulus of the substrate is within the above range, the expandability of the substrate can be improved. In addition, the tensile strength at 40% elongation can be easily adjusted to fall within a specified range.

Here, the Young's modulus of the substrate can be measured in accordance with JIS K7127. Specific measurement conditions are shown below. As a tensile tester, for example, "Tensilon RTF1150" manufactured by A&D Co., Ltd. can be used.

(Measurement condition)
・Test piece: Test piece type 5
Chuck distance: 60mm
Pull speed: 100 mm/min
Temperature: 23°C
Humidity: 50% RH

The material of the substrate preferably satisfies the above characteristics, and examples thereof include olefin resins such as low-density polyethylene, high-density polyethylene, polypropylene, polybutene, polymethylpentene, polybutadiene, ethylene-vinyl acetate copolymer, ionomer resin, ethylene (meth)acrylic acid copolymer, and ethylene (meth)acrylic acid ester copolymer; vinyl chloride resins such as polyvinyl chloride and vinyl chloride copolymer; polyester resins such as polyethylene terephthalate and polybutylene terephthalate; urethane resins; polystyrene resins; polycarbonate resins; and fluororesins. Examples of the material of the substrate include thermoplastic elastomers such as olefin elastomers, vinyl chloride elastomers, polyester elastomers, styrene elastomers, urethane elastomers, acrylic elastomers, and amide elastomers; and rubber materials such as isoprene rubber, butadiene rubber, styrene butadiene rubber, chloroprene rubber, acrylonitrile butadiene rubber, butyl rubber, halogenated butyl rubber, acrylic rubber, urethane rubber, and polysulfide rubber. These may be used alone or in combination of two or more.

Among these, olefin-based resins or vinyl chloride resins are preferred. In other words, the substrate preferably contains an olefin-based resin or vinyl chloride resin.

The substrate may contain various additives, such as plasticizers, fillers, antioxidants, light stabilizers, antistatic agents, lubricants, dispersants, flame retardants, and colorants, as necessary.

The substrate may be, for example, a single layer or a multilayer.

The surface of the substrate facing the adhesive layer may be subjected to a surface treatment to improve adhesion to the adhesive layer. The surface treatment is not particularly limited, and examples thereof include corona treatment, plasma treatment, ozone treatment, frame treatment, primer treatment, vapor deposition treatment, and alkali treatment.

The method for forming the substrate is not particularly limited, and any conventionally known film-forming method can be used, such as the casting method, calendaring method, or extrusion molding method.

By adjusting the thickness of the substrate, the puncture strength after the energy ray irradiation and 40% elongation and the tensile strength at the 40% elongation can be controlled. For example, if the substrate is thick, the puncture strength after the energy ray irradiation and 40% elongation tends to be large. On the other hand, if the substrate is thin, the tensile strength at the 40% elongation tends to be small. The thickness of the substrate is appropriately adjusted to satisfy the characteristics of the adhesive tape for semiconductor processing. The thickness of the substrate varies depending on the material of the substrate, but is, for example, 50 μm or more, may be 60 μm or more, or may be 70 μm or more. If the thickness of the substrate is within the above range, the puncture strength after the energy ray irradiation and 40% elongation can be easily adjusted to be within a predetermined range. On the other hand, the thickness of the substrate varies depending on the material of the substrate, but is, for example, 500 μm or less, may be 350 μm or less, or may be 200 μm or less. If the thickness of the substrate is within the above range, the tensile strength at the 40% elongation can be easily adjusted to be within a predetermined range.

3. Adhesive layer The adhesive layer in the present disclosure is a member disposed on one side of the substrate and having energy ray curing properties. The energy ray curable adhesive layer is cured by irradiation with energy rays, and its adhesive strength is reduced. In the energy ray curable adhesive layer, the initial adhesive strength allows the wafer or divided chips to be fixed in the dicing process. In addition, in the energy ray curable adhesive layer, the adhesive strength is reduced and peelability is improved by irradiation with energy rays to harden the layer in the pick-up process, and thus the chips can be peeled off.

Examples of energy rays include light rays such as far ultraviolet rays, ultraviolet rays, near ultraviolet rays, and infrared rays, electromagnetic waves such as X-rays and gamma rays, as well as electron beams, proton beams, and neutron beams. Among these, from the viewpoint of versatility, ultraviolet rays and electron beams are preferred, and ultraviolet rays are more preferred.

The adhesive layer is not particularly limited as long as it satisfies the above-mentioned adhesive properties, and may contain, for example, at least a resin (main adhesive agent) and an energy ray curable compound. When the adhesive layer contains an energy ray curable compound, the adhesive strength can be reduced by curing the energy ray curable compound by irradiation with energy rays, and the cohesive force is increased at this time, making it easier to peel off.

(1) Resin (main adhesive)
Examples of the resin (adhesive base) include resins that are generally used as bases for adhesives, such as acrylic resins, polyester resins, polyimide resins, and silicone resins. Among these, acrylic resins are preferred. By using acrylic resins, adhesive residue on the adherend can be reduced.

Therefore, the adhesive layer preferably contains at least an acrylic resin, an energy ray curable compound, and a crosslinking agent. In the adhesive layer, the acrylic resin is usually present as a crosslinked body in which the acrylic resin is crosslinked by the crosslinking agent, but the acrylic resin may be present as a single unit together with the crosslinked body.

(Acrylic resin)
The acrylic resin is not particularly limited, and examples thereof include (meth)acrylic acid ester polymers obtained by homopolymerizing (meth)acrylic acid esters, and (meth)acrylic acid ester copolymers obtained by copolymerizing (meth)acrylic acid esters with other monomers as the main component of (meth)acrylic acid esters. Among these, (meth)acrylic acid ester copolymers are preferred. Specific examples of (meth)acrylic acid esters and other monomers include those disclosed in JP-A-2012-31316. The other monomers can be used alone or in combination of two or more kinds. The main component here means that the copolymerization ratio is 51% by mass or more, and preferably 65% by mass or more.

Among them, as the acrylic resin, a (meth)acrylic acid ester copolymer having a (meth)acrylic acid ester as the main component and obtained by copolymerizing the (meth)acrylic acid ester with a hydroxyl group-containing monomer copolymerizable with the (meth)acrylic acid ester, or a (meth)acrylic acid ester copolymer having a (meth)acrylic acid ester as the main component and obtained by copolymerizing a hydroxyl group-containing monomer and a carboxyl group-containing monomer copolymerizable with the (meth)acrylic acid ester can be preferably used.

In this specification, (meth)acrylic acid refers to at least one of acrylic acid and methacrylic acid.

The copolymerizable hydroxyl group-containing monomer and carboxyl group-containing monomer are not particularly limited, and for example, the hydroxyl group-containing monomer and carboxyl group-containing monomer disclosed in JP 2012-31316 A can be used.

The weight-average molecular weight of the acrylic resin is, for example, preferably 200,000 to 1,000,000, and more preferably 200,000 to 800,000. By setting the weight-average molecular weight of the acrylic resin within the above range, sufficient initial adhesive strength can be achieved.

Here, in this specification, the weight average molecular weight is a polystyrene-equivalent value measured by gel permeation chromatography (GPC). The weight average molecular weight can be measured, for example, by using a measuring device such as HLC-8220GPC manufactured by Tosoh Corporation, a column such as TSKGEL-SUPERMULTIPORE-HZ-M manufactured by Tosoh Corporation, THF as the solvent, and standard polystyrenes with molecular weights of 1050, 5970, 18100, 37900, 96400, and 706000 as the standards.

In addition, when the acrylic resin is a (meth)acrylic acid ester copolymer of a hydroxyl group-containing monomer and a carboxyl group-containing monomer that are copolymerizable with the (meth)acrylic acid ester, the mass ratio of the hydroxyl group-containing monomer to the carboxyl group-containing monomer is preferably, for example, 51:49 to 100:0, and more preferably 75:25 to 100:0. If the mass ratio of each monomer is within the above range, an effective decrease in adhesive strength due to energy ray irradiation can be expected, and the occurrence of adhesive residue can be suppressed.

The acrylic resin may also be energy ray curable, for example, it may have an energy ray curable functional group in the side chain. The energy ray curable functional group preferably has, for example, an ethylenically unsaturated bond, and specific examples thereof include a (meth)acryloyl group, a vinyl group, an allyl group, etc.

(2) Energy Ray-Curable Compound The energy ray-curable compound is not particularly limited as long as it is polymerizable upon irradiation with energy rays, and examples thereof include compounds having an energy ray-curable functional group.

Examples of energy ray curable compounds include energy ray curable monomers, energy ray curable oligomers, and energy ray curable polymers. The energy ray curable polymers are polymers different from the resins (adhesive bases) described above. Among them, energy ray curable oligomers are preferred from the viewpoint of the balance of adhesive strength before and after energy ray irradiation. Also, energy ray curable monomers, energy ray curable oligomers, and energy ray curable polymers may be used in combination. For example, when an energy ray curable monomer is used in addition to an energy ray curable oligomer, the adhesive layer is cured by three-dimensional crosslinking when irradiated with energy rays, thereby reducing the adhesive strength, and the cohesive strength is increased to prevent transfer to the chip side.

Examples of energy ray-curable compounds include radically polymerizable compounds, cationic polymerizable compounds, and anionic polymerizable compounds. Among these, radically polymerizable compounds are preferred. They have a fast curing rate, can be selected from a wide variety of compounds, and can easily control physical properties such as adhesive strength before and after energy ray irradiation.

In addition, by adjusting the number of energy ray curable functional groups of the energy ray curable compound, it is possible to control the adhesive strength after the above-mentioned energy ray irradiation. Furthermore, it is possible to control the puncture strength after the above-mentioned energy ray irradiation and 40% elongation. As described above, for example, when the number of energy ray curable functional groups is increased, the crosslink density of the adhesive layer after the energy ray irradiation increases, and the adhesive strength after the above-mentioned energy ray irradiation and 40% elongation tends to decrease, and the puncture strength after the above-mentioned energy ray irradiation and 40% elongation tends to increase.

In the energy ray curable compound, the number of energy ray curable functional groups in one molecule is preferably 2 or more, more preferably 3 or more, and even more preferably 4 or more. If the number of energy ray curable functional groups is within the above range, the crosslink density of the adhesive layer after irradiation with energy rays will be sufficient, so that the desired peelability can be achieved. In addition, the occurrence of adhesive residue due to a decrease in cohesive force can be suppressed. In addition, there is no particular upper limit on the number of energy ray curable functional groups.

The energy ray curable compound is preferably a radical polymerizable oligomer, and more preferably a radical polymerizable polyfunctional oligomer. Examples of radical polymerizable oligomers include those disclosed in JP 2012-31316 A.

In addition, radically polymerizable oligomers and radically polymerizable monomers may be used as the energy ray curable compound, and among them, radically polymerizable polyfunctional oligomers and radically polymerizable polyfunctional monomers may be used. Examples of radically polymerizable monomers include those disclosed in JP 2010-173091 A.

Examples of the energy ray curable compound include (meth)acrylate monomers, (meth)acrylate oligomers, and (meth)acrylate polymers. Examples of the energy ray curable compound include urethane (meth)acrylate, polyester (meth)acrylate, and epoxy (meth)acrylate.

In addition, commercially available energy ray curable compounds may be used. For example, urethane acrylate "Shikoh UV7620EA (molecular weight: 4100)" manufactured by Mitsubishi Chemical Corporation; urethane acrylates "Art Resin UN-905 (molecular weight: 50,000 to 210,000)", "Art Resin UN-905DU1 (molecular weight: 26,000)", "Art Resin UN-951SC (molecular weight: 12,500)", "Art Resin UN-952 (molecular weight: 6,500 to 9,500)", "Art Resin UN-953 (molecular weight: 14,000 to 40,000)", "Art Resin UN-954 (molecular weight: 4,200)", and "Art Resin H-219 (molecular weight: Examples include "Art Resin H-315M (molecular weight: 6600)" and "Art Resin H-417M (molecular weight: 4000)" manufactured by Taisei Fine Chemical Co., Ltd.; acrylic urethane polymer "8BR-600 (molecular weight: 100000)" manufactured by Taisei Fine Chemical Co., Ltd.; polymer acrylate "Unidic V-6850" manufactured by DIC Corporation; acrylic polymers "SMP-250AP (molecular weight: 20000-30000)" and "SMP-360A (molecular weight: 20000-30000)" manufactured by Kyoeisha Chemical Co., Ltd.; and acrylic resin acrylate "HA7975" manufactured by Showa Denko Materials Co., Ltd.

The energy ray curable compounds may be used alone or in combination of two or more.

The weight average molecular weight of the energy ray curable compound is not particularly limited, but is preferably 30,000 or less, more preferably 10,000 or less, and even more preferably 8,000 or less. If the weight average molecular weight of the energy ray curable compound is within the above range, it exhibits sufficient compatibility with the acrylic resin (main adhesive agent), and the adhesive layer exhibits the desired adhesive strength before irradiation with energy rays, and after irradiation with energy rays, the occurrence of adhesive residue is suppressed and it can be easily peeled off. On the other hand, the weight average molecular weight of the energy ray curable resin composition can be, for example, 500 or more.

In addition, by adjusting the content of the energy ray curable compound, it is possible to control the adhesive strength to the SUS plate after irradiation with the energy ray. Furthermore, it is possible to control the puncture strength after the above-mentioned irradiation with the energy ray and after 40% elongation. If the content of the energy ray curable compound is high, the adhesive strength to the SUS plate after irradiation with the energy ray tends to be small, and the puncture strength after the above-mentioned irradiation with the energy ray and after 40% elongation tends to be large.

The content of the energy ray curable compound is, for example, preferably 5 parts by mass or more and 150 parts by mass or less, more preferably 20 parts by mass or more and 100 parts by mass or less, and even more preferably 50 parts by mass or more and 80 parts by mass or less, per 100 parts by mass of the resin (main adhesive agent). If the content of the energy ray curable compound is within the above range, the crosslink density of the adhesive layer after irradiation with energy rays will be sufficient, so that the desired peelability can be achieved. In addition, the occurrence of adhesive residue due to a decrease in cohesive force can be suppressed.

(3) Polymerization Initiator The adhesive layer may contain a polymerization initiator in addition to the resin (main adhesive agent) and the energy ray-curable compound.

As the polymerization initiator, a general photopolymerization initiator can be used. Specific examples include acetophenones, benzophenones, α-hydroxyketones, benzyl methyl ketals, α-aminoketones, and bisacylphosphine oxides. When a urethane acrylate is used as the energy ray curable compound, the polymerization initiator is preferably a bisacylphosphine polymerization initiator. Since this polymerization initiator has heat resistance, when the adhesive composition is applied to a substrate and irradiated with energy rays, the energy ray curable compound can be reliably cured even when the energy ray irradiation is performed through the substrate.

The polymerization initiator preferably has an absorption at wavelengths of 230 nm or more, and preferably has an absorption at wavelengths of 300 nm to 400 nm. Such a polymerization initiator can absorb a wide energy ray with a wavelength of 300 nm or more and efficiently generate active species that induce a polymerization reaction of the energy ray curable compound. Therefore, even with a small amount of energy ray irradiation, the energy ray curable compound can be efficiently cured and easily peeled off. In addition, as described later, resins and the like can be used for the substrate, and many resins absorb energy rays with wavelengths of up to about 300 nm, but transmit energy rays with wavelengths of about 300 nm or more. Furthermore, in recent years, LED lamps with wavelengths of 300 nm or more are often used in energy ray irradiation devices. Therefore, by using a polymerization initiator with an absorption at wavelengths of 230 nm or more, the energy ray curable compound can be cured using the energy rays that have transmitted through the substrate.

The content of the polymerization initiator is, for example, preferably 0.01 parts by mass or more and 10 parts by mass or less, and more preferably 0.5 parts by mass or more and 6 parts by mass or less, relative to a total of 100 parts by mass of the resin (main adhesive agent) and the energy ray curable compound. If the content of the polymerization initiator is less than the above range, the polymerization reaction of the energy ray curable compound does not occur sufficiently, and the adhesive strength of the adhesive layer after irradiation with energy rays becomes excessively high, and peelability may not be achieved. On the other hand, if the content of the polymerization initiator exceeds the above range, the energy rays may only reach the vicinity of the energy ray irradiated surface, and the adhesive layer may not be cured sufficiently. In addition, the cohesive force may decrease, which may cause glue residue.

(4) Crosslinking Agent The adhesive layer may contain a crosslinking agent in addition to the resin (main adhesive agent) and the energy ray-curable compound.

The crosslinking agent is not particularly limited as long as it crosslinks at least between resins (main adhesives), and can be appropriately selected depending on the type of resin (main adhesive), etc. Examples include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, metal chelate-based crosslinking agents, etc. Specific examples of isocyanate-based crosslinking agents and epoxy-based crosslinking agents include those disclosed in JP 2012-31316 A. The crosslinking agents can be used alone or in combination of two or more types.

The content of the crosslinking agent can be set appropriately depending on the type of crosslinking agent, but for example, it is preferably 0.01 to 15 parts by mass, and more preferably 0.01 to 10 parts by mass, per 100 parts by mass of resin (main adhesive). If the content of the crosslinking agent is less than the above range, the adhesion may be poor, or the adhesive layer may undergo cohesive failure when peeling off the chip, resulting in glue residue. On the other hand, if the content of the crosslinking agent exceeds the above range, the crosslinking agent may remain in the adhesive layer as unreacted monomer after irradiation with energy rays, which may cause glue residue due to a decrease in cohesive force.

(5) Additives The adhesive layer may contain various additives as necessary, such as a tackifier, an antistatic agent, a plasticizer, a silane coupling agent, a metal chelating agent, a surfactant, an antioxidant, an ultraviolet absorber, a colorant, a preservative, an antifoaming agent, and a wettability adjuster.

The adhesive layer may also contain an adhesive strength adjuster. The adhesive strength adjuster may be used, for example, to adjust the peelability and tackiness of the separator. Examples of the adhesive strength adjuster include acrylic block copolymers and polyester resins. Commercially available acrylic block copolymers and polyester resins may also be used. Specific examples of acrylic block copolymers include Kuraray's Clarity series (e.g., "LA4285", "LA2270", "LA2250", "LA2140", "LA2330", "LA3320", etc.) and Arkema's NANOSTRENGTH (e.g., "M22N", etc.). Examples of polyester resins include Toyobo's Byron series (e.g., "Byron 200", "Byron 600", etc.) and Unitika's Elitel series (e.g., "Ellite UE3210", "Ellite UE9200", etc.).

(6) Storage modulus of adhesive layer In the adhesive layer of the present disclosure, the storage modulus at a temperature of 25° C. and a frequency of 1 Hz after energy ray irradiation is preferably, for example, 10 MPa or more, more preferably 100 MPa or more. If the storage modulus is within the above range, the puncture strength after the energy ray irradiation and 40% elongation can be easily adjusted to be within a predetermined range. On the other hand, the lower limit of the storage modulus after the energy ray irradiation is not particularly limited, but is, for example, 5000 MPa or less. If the storage modulus is within the above range, the adhesive layer becomes moderately soft, so that cracking of the adhesive layer after energy ray irradiation can be suppressed.

Here, the storage modulus is a value measured by a dynamic viscoelasticity measuring device (DMA). When measuring the storage modulus of the adhesive layer by a dynamic viscoelasticity measuring device (DMA), the adhesive layer is rolled up to form a cylindrical sample with a diameter of 5 mm to 7 mm and a height of approximately 5 mm to 10 mm. First, the cylindrical measurement sample is attached between the compression fixtures (parallel plates φ8 mm) of the dynamic viscoelasticity measuring device. Next, a compressive load is applied at a temperature of 25°C and a frequency of 1 Hz to perform dynamic viscoelasticity measurement. For example, the RSA-3 manufactured by TA Instruments Japan can be used as the dynamic viscoelasticity measuring device.

(7) Thickness and Formation Method of Adhesive Layer The thickness of the adhesive layer may be any thickness that provides sufficient adhesive strength and allows energy rays to penetrate to the inside, and is, for example, from 3 μm to 50 μm, and preferably from 5 μm to 40 μm.

Methods for forming the adhesive layer include, for example, a method of applying an adhesive composition onto a substrate, and a method of applying an adhesive composition onto a separator to form an adhesive layer, and then laminating the adhesive layer and the substrate.

4. Other Configurations The adhesive tape for semiconductor processing according to the present disclosure may have other configurations, if necessary, in addition to the above-mentioned substrate and adhesive layer.

The adhesive tape for semiconductor processing of the present disclosure may have a separator on the surface of the adhesive layer opposite the substrate. The separator can protect the adhesive layer.

The adhesive tape for semiconductor processing of the present disclosure may also have a primer layer between the substrate and the adhesive layer. The primer layer can increase the adhesion between the substrate and the adhesive layer.

5. Uses The adhesive tape for semiconductor processing according to the present disclosure can be suitably used as a dicing tape.

This disclosure is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and anything that has substantially the same configuration as the technical ideas described in the claims of this disclosure and has similar effects is included within the technical scope of this disclosure.

The following examples and comparative examples will further explain this disclosure.

[Materials for adhesive composition]
The materials used in the adhesive composition are shown below.
・Adhesive base A (acrylic ester copolymer, weight average molecular weight 800,000)
・Adhesive base B (acrylic ester copolymer, weight average molecular weight 200,000)
UV-curable compound A (urethane acrylate, 10 functional groups, molecular weight 2000)
UV-curable compound B (urethane acrylate, 9 functional groups, molecular weight 4100)
UV-curable compound C (urethane acrylate, functional group number 6, molecular weight 4200)
UV-curable compound D (urethane acrylate, 10 functional groups, molecular weight 500 to 1200)
Crosslinking agent A: (isocyanate-based curing agent, toluylene diisocyanate adduct of trimethylolpropane)
Crosslinking agent B (epoxy curing agent, N,N,N',N'-tetraglycidyl-m-xylylenediamine)
Crosslinking agent C: (metal chelate curing agent, aluminum trisacetylacetonate)
Photopolymerization initiator (acylphosphine oxide photopolymerization initiator, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide)
Additives (methyl methacrylate/n-butyl acrylate copolymer, n-butyl acrylate content: 50% by mass)

[Example 1]
(1) Formation of Adhesive Layer 100 parts by mass of acrylic adhesive main agent A, 50 parts by mass of ultraviolet curable compound A, 3 parts by mass of crosslinking agent A, and 5 parts by mass of photopolymerization initiator were diluted with a mixed solvent of methyl ethyl ketone and toluene (mixing ratio 1:1) to a solid content of 20%, and thoroughly dispersed to prepare an adhesive composition.

The above adhesive composition was applied onto a polyethylene terephthalate (PET) separator so that the thickness after drying was 20 μm, and the adhesive layer was formed by drying in an oven at 110°C for 3 minutes.

(2) Preparation of Adhesive Tape for Semiconductor Processing A resin composition containing 70 parts by mass of vinyl chloride resin, 25 parts by mass of plasticizer, and 0.5 parts by mass of nonylphenol was formed into a polyvinyl chloride film having a thickness of 90 μm by a calendar method.

The above-mentioned polyvinyl chloride film was laminated onto the above-mentioned adhesive layer as a substrate, and then aged at 50°C for three days to produce an adhesive tape for semiconductor processing.

[Example 2]
(1) Formation of Adhesive Layer An adhesive layer having a thickness of 20 μm was formed in the same manner as in Example 1, except that an adhesive composition was prepared as follows.

100 parts by weight of acrylic adhesive base B, 40 parts by weight of UV-curable compound B, 30 parts by weight of UV-curable compound C, 3 parts by weight of crosslinker A, 7 parts by weight of photopolymerization initiator, and 0.5 parts by weight of additive were diluted with a mixed solvent of methyl ethyl ketone and toluene (mixing ratio 1:1) to a solid content of 20%, and thoroughly dispersed to prepare an adhesive composition.

(2) Preparation of Adhesive Tape for Semiconductor Processing A resin composition containing 70 parts by mass of vinyl chloride resin, 25 parts by mass of plasticizer, and 0.3 parts by mass of nonylphenol was used to form a film by a calendar method to prepare a polyvinyl chloride film having a thickness of 90 μm.

The polyvinyl chloride film was laminated onto the adhesive layer as a substrate, and then an adhesive tape for semiconductor processing was produced in the same manner as in Example 1.

[Example 3]
(1) Formation of Adhesive Layer In the same manner as in Example 2, an adhesive layer having a thickness of 20 μm was formed.

(2) Preparation of Adhesive Tape for Semiconductor Processing A polyvinyl chloride film having a thickness of 90 μm was prepared in the same manner as in Example 1.

The above-mentioned polyvinyl chloride (PVC) film was laminated onto the above-mentioned adhesive layer as a substrate, and then an adhesive tape for semiconductor processing was produced in the same manner as in Example 1.

[Example 4]
(1) Formation of Adhesive Layer An adhesive layer was formed in the same manner as in Example 1, except that the thickness was set to 10 μm.

(2) Preparation of Adhesive Tape for Semiconductor Processing A resin composition containing 70 parts by mass of polyvinyl chloride resin and 30 parts by mass of a plasticizer (bis(2-ethylhexyl) terephthalate) was formed into a film by a calendar method to prepare a polyvinyl chloride film having a thickness of 200 μm.

The above-mentioned polyvinyl chloride film was laminated onto the above-mentioned adhesive layer as a substrate, and then an adhesive tape for semiconductor processing was produced in the same manner as in Example 1.

[Example 5]
(1) Formation of Adhesive Layer An adhesive layer having a thickness of 20 μm was formed in the same manner as in Example 1, except that an adhesive composition was prepared as follows.

100 parts by weight of acrylic adhesive base B, 70 parts by weight of ultraviolet curable compound B, 0.35 parts by weight of crosslinker B, 0.2 parts by weight of crosslinker C, 2.8 parts by weight of photopolymerization initiator, and 1 part by weight of additive were diluted with a mixed solvent of methyl ethyl ketone and toluene (mixture ratio 1:1) to a solid content of 20%, and thoroughly dispersed to prepare an adhesive composition.

(2) Preparation of Adhesive Tape for Semiconductor Processing A resin composition containing 70 parts by mass of vinyl chloride resin, 40 parts by mass of plasticizer, and 0.5 parts by mass of stabilizer was used to form a film by a casting method, to prepare a polyvinyl chloride film having a thickness of 90 μm.

The above-mentioned polyvinyl chloride film was laminated onto the above-mentioned adhesive layer as a substrate, and then an adhesive tape for semiconductor processing was produced in the same manner as in Example 1.

[Example 6]
(1) Formation of Adhesive Layer An adhesive layer having a thickness of 20 μm was formed in the same manner as in Example 1, except that an adhesive composition was prepared as follows.

100 parts by weight of acrylic adhesive base B, 70 parts by weight of ultraviolet-curable compound D, 0.35 parts by weight of crosslinking agent B, 4.2 parts by weight of photopolymerization initiator, and 1.5 parts by weight of additive were diluted with a mixed solvent of methyl ethyl ketone and toluene (mixture ratio 1:1) to a solid content of 20%, and thoroughly dispersed to prepare an adhesive composition.

(2) Preparation of adhesive tape for semiconductor processing A polyvinyl chloride film having a thickness of 90 μm was prepared in the same manner as in Example 5.

The above-mentioned polyvinyl chloride film was laminated onto the above-mentioned adhesive layer as a substrate, and then an adhesive tape for semiconductor processing was produced in the same manner as in Example 1.

[Example 7]
(1) Formation of Adhesive Layer An adhesive layer having a thickness of 20 μm was formed in the same manner as in Example 1, except that an adhesive composition was prepared as follows.

100 parts by weight of acrylic adhesive base B, 60 parts by weight of ultraviolet curable compound B, 0.35 parts by weight of crosslinker B, 0.2 parts by weight of crosslinker C, 2.4 parts by weight of photopolymerization initiator, and 1 part by weight of additive were diluted with a mixed solvent of methyl ethyl ketone and toluene (mixture ratio 1:1) to a solid content of 20%, and thoroughly dispersed to prepare an adhesive composition.

(2) Preparation of Adhesive Tape for Semiconductor Processing A polyvinyl chloride film having a thickness of 90 μm was prepared in the same manner as in Example 2.

The above-mentioned polyvinyl chloride film was laminated onto the above-mentioned adhesive layer as a substrate, and then an adhesive tape for semiconductor processing was produced in the same manner as in Example 1.

[Comparative Example 1]
(1) Formation of Adhesive Layer In the same manner as in Example 1, an adhesive layer having a thickness of 20 μm was formed.

(2) Preparation of Adhesive Tape for Semiconductor Processing A polyvinyl chloride film was prepared in the same manner as in Example 2, except that the thickness was 70 μm.

The above-mentioned polyvinyl chloride film was laminated onto the above-mentioned adhesive layer as a substrate, and then an adhesive tape for semiconductor processing was produced in the same manner as in Example 1.

[Comparative Example 2]
(1) Formation of Adhesive Layer An adhesive layer having a thickness of 20 μm was formed in the same manner as in Example 1, except that an adhesive composition was prepared as follows.

100 parts by weight of acrylic adhesive base A, 50 parts by weight of ultraviolet-curable compound A, 3 parts by weight of crosslinking agent A, and 1.5 parts by weight of photopolymerization initiator were diluted with a mixed solvent of methyl ethyl ketone and toluene (mixture ratio 1:1) to a solid content of 20%, and thoroughly dispersed to prepare an adhesive composition.

(2) Preparation of Adhesive Tape for Semiconductor Processing A PE film having a thickness of 100 μm was prepared as a substrate.

The above PE film was laminated onto the above adhesive layer as a substrate, and then an adhesive tape for semiconductor processing was produced in the same manner as in Example 1.

[Comparative Example 3]
(1) Formation of Adhesive Layer An adhesive layer was formed in the same manner as in Comparative Example 2, except that the thickness was set to 10 μm.

(2) Preparation of Adhesive Tape for Semiconductor Processing A PET film having a thickness of 100 μm was prepared as a substrate.

The above PET film was laminated onto the above adhesive layer as a substrate, and then an adhesive tape for semiconductor processing was produced in the same manner as in Example 1.

[Comparative Example 4]
(1) Formation of Adhesive Layer An adhesive layer was formed in the same manner as in Comparative Example 2, except that the thickness was set to 10 μm.

(2) Preparation of Adhesive Tape for Semiconductor Processing A PET film having a thickness of 188 μm was prepared as a substrate.

The above PET film was laminated onto the above adhesive layer as a substrate, and then an adhesive tape for semiconductor processing was produced in the same manner as in Example 1.

[Comparative Example 5]
(1) Formation of Adhesive Layer An adhesive layer having a thickness of 10 μm was formed in the same manner as in Example 1, except that an adhesive composition was prepared as follows.

100 parts by weight of acrylic adhesive base A, 50 parts by weight of ultraviolet-curable compound A, 1.5 parts by weight of crosslinking agent A, and 1.5 parts by weight of photopolymerization initiator were diluted with a mixed solvent of methyl ethyl ketone and toluene (mixture ratio 1:1) to a solid content of 20%, and thoroughly dispersed to prepare an adhesive composition.

(2) Preparation of Adhesive Tape for Semiconductor Processing A PET film having a thickness of 188 μm was prepared as a substrate.

The above PET film was laminated onto the above adhesive layer as a substrate, and then an adhesive tape for semiconductor processing was produced in the same manner as in Example 1.

[Comparative Example 6]
(1) Formation of Adhesive Layer In the same manner as in Example 6, an adhesive layer having a thickness of 20 μm was formed.

(2) Preparation of Adhesive Tape for Semiconductor Processing A polyvinyl chloride film was prepared in the same manner as in Example 2, except that the thickness was changed to 70 μm.

The above-mentioned polyvinyl chloride film was laminated onto the above-mentioned adhesive layer as a substrate, and then an adhesive tape for semiconductor processing was produced in the same manner as in Example 1.

[Comparative Example 7]
(1) Formation of Adhesive Layer In the same manner as in Example 7, an adhesive layer having a thickness of 20 μm was formed.

(2) Preparation of Adhesive Tape for Semiconductor Processing A polyvinyl chloride film was prepared in the same manner as in Example 5, except that the thickness was changed to 90 μm.

The polyvinyl chloride film was laminated onto the adhesive layer as a substrate, and then an adhesive tape for semiconductor processing was produced in the same manner as in Example 1.

[Evaluation 1]
(1) Puncture strength (1-1) Puncture strength after energy ray irradiation and 40% elongation The puncture strength of the semiconductor processing adhesive tape after energy ray irradiation and 40% elongation was measured by the following method. First, a test piece of semiconductor processing adhesive tape with a width of 45 mm and a length of 150 mm was prepared. At this time, the length direction of the test piece is the MD direction. The test piece of the semiconductor processing adhesive tape was irradiated with ultraviolet light from the substrate side surface so that the accumulated light amount was 500 mJ / cm ² , and the adhesive layer was cured. Next, the separator was peeled off from the test piece of the semiconductor processing adhesive tape. The test piece of the semiconductor processing adhesive tape was elongated by 40% in the MD direction at a tensile speed of 100 mm / min. The adhesive layer side of the test piece of the semiconductor processing adhesive tape after 40% elongation was fixed to a puncture test jig (TKS-250N manufactured by Imada Co., Ltd.) having a circular opening with a diameter of 20 mm. A pin (TP-20 manufactured by Imada, tip diameter: 1 mm, tip shape: semicircular with radius of 0.5 mm) was pierced from the substrate side at a piercing speed of 300 mm/min at the center of the circular opening, and the maximum load at the breaking point was measured using a digital force gauge (ZTS-500N manufactured by Imada). After the adhesive tape for semiconductor processing was stretched, the time until the piercing strength was measured was 1 minute. The number of test pieces was 5, and the average value was calculated, and this average value was defined as the piercing strength. The piercing test was performed in an environment with a temperature of 25°C ± 5°C, a humidity of 40% RH to 60% RH, and energy rays blocked.

(1-2) Puncture strength before energy ray irradiation and after 40% elongation The puncture strength before energy ray irradiation and after 40% elongation (initial puncture strength) was measured in the same manner as above, except that ultraviolet light was not irradiated.

(2) Adhesive strength to SUS plate (2-1) Adhesive strength to SUS plate after energy ray irradiation The adhesive strength to SUS plate after energy ray irradiation was measured in accordance with JIS Z0237:2009 (Adhesive tape and adhesive sheet test method) test method method 1 (temperature 23 ° C. humidity 50% RH, tape and sheet peeled off at 180 ° against stainless steel test plate). First, the separator was peeled off from the semiconductor processing adhesive tape and attached to the SUS plate using a manual roller. Ultraviolet light was irradiated from the substrate side of the semiconductor processing adhesive tape so that the accumulated light amount was 500 mJ / cm ² , and the adhesive layer was cured. Next, the adhesive strength to the SUS plate after energy ray irradiation was measured by peeling off the test piece in the length direction under the conditions of width 25 mm, peel angle 180 °, and peel speed 300 mm / min. The SUS plate used was a SUS304 plate with a BA surface finish, a thickness of 1.5 mm, a width of 100 mm and a length of 150 mm.

(2-2) Adhesive Strength to SUS Plate before Irradiation with Energy Rays The adhesive strength to a SUS plate before irradiation with energy rays (initial adhesive strength to a SUS plate) was measured in the same manner as above, except that ultraviolet light was not irradiated.

(3) Tensile strength at 40% elongation (3-1) Tensile strength at 40% elongation before energy ray irradiation The tensile strength at 40% elongation of the adhesive tape for semiconductor processing before energy ray irradiation was measured as follows. First, a test piece of the adhesive tape for semiconductor processing having a width of 45 mm and a length of 150 mm was prepared, and the separator was peeled off. At this time, the length direction of the test piece was the MD direction. The tensile strength of this test piece was measured when it was elongated by 40% with a chuck distance of 50 mm and a tensile speed of 100 mm/min. A &D's"TensilonRTF1350" was used as the tensile tester.

(3-2) Tensile strength at 40% elongation after energy ray irradiation The tensile strength at 40% elongation after energy ray irradiation was measured in the same manner as above, except that before the separator was peeled off, the substrate side surface of the test piece of the adhesive tape for semiconductor processing was irradiated with ultraviolet light so that the integrated light amount was 500 ^mJ /cm2 to harden the adhesive layer.

(4) Stress at break (4-1) Stress at break after energy ray irradiation The stress at break of the adhesive tape for semiconductor processing after energy ray irradiation was measured as follows. First, a test piece of the adhesive tape for semiconductor processing type 5 was prepared. The adhesive layer was cured by irradiating the adhesive tape for semiconductor processing from the substrate side of the test piece of the adhesive tape for semiconductor processing with ultraviolet light so that the accumulated light amount was 500 mJ/ ^cm2 . Next, the separator was peeled off from the test piece of the adhesive tape for semiconductor processing. Next, the test piece of the adhesive tape for semiconductor processing was pulled in the MD direction or TD direction under the conditions of a chuck distance of 60 mm and a pulling speed of 100 mm/min, and the stress at the time of break was measured. A &D's"TensilonRTF1150" was used as the tensile tester.

(4-2) Stress at Break Before Irradiation with Energy Rays The stress at break when the sample was pulled in the MD or TD was measured in the same manner as above, except that the sample was not irradiated with ultraviolet light.

(5) Elongation at break (5-1) Elongation at break after energy ray irradiation In the same manner as in "(4-1) Stress at break after energy ray irradiation" described above, the pressure-sensitive adhesive tape for semiconductor processing after energy ray irradiation was pulled in the MD direction or TD direction, and the tensile elongation at break was measured.

(5-2) Elongation at break before irradiation with energy rays The sample was pulled in the MD or TD direction in the same manner as above, except that no ultraviolet light was irradiated, and the tensile elongation at break was measured.

(6) Young's modulus of adhesive tape for semiconductor processing (6-1) Young's modulus after energy ray irradiation The stress at break of the adhesive tape for semiconductor processing after energy ray irradiation was measured as follows. First, a test piece of the adhesive tape for semiconductor processing type 5 was prepared. The adhesive layer was cured by irradiating the test piece of the adhesive tape for semiconductor processing from the substrate side of the test piece of the adhesive tape for semiconductor processing with ultraviolet light so that the accumulated light amount was 500 mJ/ ^cm2 . Next, the separator was peeled off from the test piece of the adhesive tape for semiconductor processing. Next, the Young's modulus of the test piece of the adhesive tape for semiconductor processing was measured under the conditions of a chuck distance of 60 mm and a pulling speed of 100 mm/min.

(6-2) Young's modulus before irradiation with energy rays The Young's modulus was measured by pulling in the MD or TD direction in the same manner as above, except that the ultraviolet light was not irradiated.

[Evaluation 2]
(1) Processability The adhesive tape for semiconductor processing obtained above was attached to a silicon wafer having a diameter of 8 inches and a thickness of 100 μm. Next, the silicon wafer was diced to separate into individual chips having a size of 3 mm×3 mm, and the presence or absence of chip scattering was confirmed. Then, the processability was evaluated according to the following criteria.

(Evaluation criteria)
A: The rate of chipping was less than 1%.
B: The rate of chipping was 1% or more and 5% or less.
C: The rate of chipping was more than 5%.

(2) Peelability (resistance to tearing)
Using a lamination device (a semi-automatic film lamination device manufactured by Technovision), the adhesive tape for semiconductor processing was laminated to a SUS ring frame at a speed of 10 mm/s. Then, it was left to stand for 60 minutes. Next, ultraviolet light was irradiated from the substrate side of the adhesive tape for semiconductor processing so that the accumulated light amount was 500 mJ/ ^cm2 . Next, the adhesive tape for semiconductor processing was observed for the presence or absence of breakage when peeled off from the ring frame. Five pieces of the adhesive tape for semiconductor processing of each of the examples and the comparative examples were prepared, and the peelability was confirmed and evaluated according to the following criteria.

(Evaluation criteria)
A: No tears occurred in any of the tapes.
B: Some of the tapes were torn.
C: Film tear occurred in all tapes.

(3) Flexibility Using a wafer expander (a tape expansion device manufactured by Technovision), an adhesive tape for semiconductor processing attached to a SUS ring frame was expanded at an expansion stage stroke of 35 mm, an expansion speed of 6 mm/s, and an expansion stage temperature of 40° C. The flexibility (expandability) at that time was evaluated according to the following criteria.

(Evaluation criteria)
A: Even when the extension stage stroke was changed to 40 mm, it was still possible to achieve sufficient extension.
B: Sufficient expansion was achieved.
C: The expansion was insufficient.
D: It was not possible to expand.

As shown in Tables 1 and 2, the adhesive tapes for semiconductor processing of Examples 1 to 7 had good peelability (resistance to tearing) and flexibility. On the other hand, the adhesive tapes for semiconductor processing of Comparative Examples 1, 2, and 6 had low puncture strength after energy ray irradiation and 40% elongation, resulting in poor peelability (resistance to tearing). The adhesive tapes for semiconductor processing of Comparative Examples 3 to 5 had high tensile strength at 40% elongation, resulting in poor flexibility. Comparative Example 7 had high adhesive strength to SUS plate after energy ray irradiation, resulting in poor peelability (resistance to tearing).

That is, the present disclosure provides the following inventions.
[1] An adhesive tape for semiconductor processing having a substrate and an energy ray-curable adhesive layer disposed on one side of the substrate, wherein the adhesive tape for semiconductor processing has a tensile strength of 200 N/45 mm or less at 40% elongation, a puncture strength of 7.2 N or more after irradiation with energy rays and after 40% elongation, and an adhesive strength to a SUS plate after irradiation with energy rays of 1.4 N/25 mm or less.

Reference Signs List 1: Substrate 2: Adhesive layer 10: Adhesive tape for semiconductor processing

Claims (1)

A semiconductor processing adhesive tape having a substrate and an energy ray-curable adhesive layer disposed on one surface of the substrate,
The tensile strength at 40% elongation is 200N/45mm or less,
The puncture strength after irradiation with energy rays and elongation of 40% is 7.2 N or more,
An adhesive tape for semiconductor processing, having an adhesive strength to a SUS plate after irradiation with energy rays of 1.4 N/25 mm or less.