Double-sided adhesive sheet for transfer

Abstract

To provide a double-sided adhesive sheet for transfer, appropriate for efficient installation onto a mounting substrate without damaging a minute electronic component such as a semiconductor chip.SOLUTION: A double-sided adhesive sheet 1 for transfer has a laminate structure including a first adhesive layer 11, a substrate 10 and a second adhesive layer 12 laminated in this order. The first adhesive layer 11 is composed of a low-viscosity adhesive layer. The second adhesive layer 12 is composed of a detachable adhesive layer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a double-sided adhesive sheet for transfer. More specifically, the present invention relates to a double-sided adhesive sheet for transfer that can be suitably used for transferring minute electronic components such as semiconductor chips. [Background technology]

[0002] In the manufacturing process of semiconductor devices, semiconductor wafers are generally diced into individual pieces while temporarily fixed on a dicing tape. The individual semiconductor chips are then pushed from the dicing tape side on the back of the wafer using a pin member, picked up by a suction jig called a collet, and mounted on a mounting substrate such as a circuit board (for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2019-9203 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, advances in microfabrication technology have led to the miniaturization and thinning of semiconductor chips, which sometimes resulted in damage to the chips during pickup with a collet. Therefore, mounting such miniaturized and thin semiconductor chips requires weak contact or no contact at all. Furthermore, with the miniaturization and multi-layering of semiconductor devices progressing, there is a growing demand for densely multi-layer mounting of numerous tiny semiconductor chips on a substrate, and the problem is that individual mounting using collets is inefficient.

[0005] The present invention has been made in view of the above-mentioned problems, and its objective is to provide a double-sided adhesive sheet for transfer that is suitable for efficiently mounting minute electronic components such as semiconductor chips onto a mounting substrate without damaging them. [Means for solving the problem]

[0006] As a result of diligent research to achieve the above objective, the inventors have found that a double-sided adhesive sheet, in which a first adhesive layer for receiving minute electronic components such as semiconductor chips is made of a low-tack adhesive layer and a second adhesive layer for temporarily fixing to a carrier substrate is made of a release adhesive layer, makes it possible to efficiently mount minute electronic components such as semiconductor chips onto a mounting substrate without damaging them. The present invention was completed based on these findings.

[0007] In other words, the first aspect of the present invention provides a double-sided adhesive sheet for transfer in which a first adhesive layer, a substrate, and a second adhesive layer are laminated in this order. The double-sided adhesive sheet for transfer according to the first aspect of the present invention allows the first adhesive layer to receive fine, thin electronic components such as semiconductor chips when mounting them onto a mounting substrate such as a circuit board, instead of picking them up individually with a collet or the like. By using the double-sided adhesive sheet for transfer according to the first aspect of the present invention for mounting electronic components, the first adhesive layer can receive multiple electronic components that have been separated into individual pieces by dicing all at once, eliminating the need to pick them up individually. Furthermore, the electronic components received by the first adhesive layer can be mounted by transferring them all at once onto a large-area mounting substrate, thereby dramatically improving manufacturing efficiency. On the other hand, the second adhesive layer is an adhesive layer for temporarily fixing the first side transfer double-sided adhesive sheet of the present invention to a base substrate (carrier substrate).

[0008] In the first side transfer double-sided adhesive sheet of the present invention, the first adhesive layer is an adhesive layer for receiving and holding electronic components, and is preferably made of a low-tack adhesive layer. The configuration in which the first adhesive layer is made of a low-tack adhesive layer is preferable in that it can reduce the force applied to the electronic component when receiving it, thereby suppressing damage to the electronic component. Furthermore, when the first adhesive layer receives an electronic component without contact, for example, the electronic component is peeled off the dicing tape by pressing it with a pin member and dropped onto the first adhesive layer. However, when the first adhesive layer receives the dropped electronic component, it may bounce and not be received accurately. When this phenomenon occurs, the positional accuracy of the electronic product may decrease and contact failure may occur. The configuration in which the first adhesive layer is made of a low-tack adhesive layer is also preferable in that when the first adhesive layer receives an electronic component without contact, the electronic component is more likely to be caught by the first adhesive layer without bouncing, and can be received with good positional accuracy. Furthermore, the present invention is also preferable because, when mounting electronic components received by the first side transfer double-sided adhesive sheet onto a mounting substrate, the electronic components can be easily peeled off from the first adhesive layer.

[0009] Furthermore, in the first side-transfer double-sided adhesive sheet of the present invention, the second adhesive layer is an adhesive layer for temporary fixing to the carrier substrate, and is preferably made of a release adhesive layer. The configuration in which the second adhesive layer is made of a release adhesive layer is preferable because the second adhesive layer can be peeled off from the carrier substrate without contamination such as adhesive residue, thereby improving reworkability.

[0010] In the first side transfer double-sided adhesive sheet of the present invention, the storage modulus of the first adhesive layer at a frequency of 1 Hz and 25°C measured by AFM-DMA (hereinafter sometimes referred to as "E'1a" in this specification) is preferably 50 MPa or less. This configuration is preferable for ensuring reliable adhesion of the electronic component received by the first adhesive layer. If E'1a is too high, the adhesion of the electronic component to the first adhesive layer decreases, which may cause problems such as misalignment or falling of the electronic component. From the viewpoint of adhesion of the electronic component to the first adhesive layer, E'1a is preferably 40 MPa or less, and more preferably 30 MPa or less. It may also be 20 MPa or less, or 10 MPa or less. On the other hand, from the viewpoint of transferability from the first adhesive layer to the circuit board, E'1a is preferably 0.1 MPa or more. If E'1a is too low, the adhesion of the electronic component to the first adhesive layer becomes too high, which may impair the transferability when mounting to the mounting board. From the viewpoint of transferability of electronic components to mounting substrates, E'1a is preferably 0.2 MPa or higher, and more preferably 0.5 MPa or higher.

[0011] In the first side transfer double-sided adhesive sheet of the present invention, the storage modulus of the first adhesive layer at a frequency of 1 kHz and 25°C measured by AFM-DMA (hereinafter sometimes referred to as "E'1b" in this specification) is preferably 100 MPa or less. This configuration is preferable in that when the first adhesive layer receives an electronic component without contact, the electronic component is not repelled by the surface of the first adhesive layer and can be received with good positional accuracy. If E'1b is too high, when the electronic component is dropped and received without contact with the surface of the first adhesive layer, the electronic component is likely to be repelled, shift from its predetermined position, or flip over, reducing positional accuracy. From the viewpoint of positional accuracy of the electronic component relative to the first adhesive layer, E'1b is preferably 90 MPa or less, and more preferably 80 MPa or less. It may also be 70 MPa or less, 60 MPa or less, 50 MPa or less, 40 MPa or less, 30 MPa or less, and especially 20 MPa or less. On the other hand, from the viewpoint of transferability from the first adhesive layer to the circuit board, E'1b is preferably 0.5 MPa or higher. If E'1b is too low, the adhesion of the electronic component to the first adhesive layer will be high, and the transferability when mounting to the mounting board may be impaired, such as when the electronic component falls and becomes embedded in the first adhesive layer. From the viewpoint of transferability of the electronic component to the mounting board, E'1b is preferably 0.7 MPa or higher, and more preferably 1 MPa or higher.

[0012] In the first side transfer double-sided adhesive sheet of the present invention, it is preferable that the ratio (E'1b / E'1a) of the storage modulus of the first adhesive layer at a frequency of 1kHz and 25℃ (E'1b) to the storage modulus of the first adhesive layer at a frequency of 1Hz and 25℃ (E'1a) measured by AFM-DMA of the first adhesive layer is greater than 1. This configuration is preferable in that it provides a good balance of adhesion of electronic components to the first adhesive layer, positional accuracy, and transferability to the mounting substrate. From the viewpoint of balancing adhesion of electronic components, positional accuracy, and transferability to the mounting substrate, E'1b / E'1a is preferably 1.05 or more, and more preferably 1.1 or more. There is no particular upper limit to E'1b / E'1a, but from the viewpoint of the above balance, it is preferably 3 or less.

[0013] In the first side transfer double-sided adhesive sheet of the present invention, the loss modulus of elasticity of the first adhesive layer at a frequency of 1 Hz and 25°C measured by AFM-DMA (hereinafter sometimes referred to as "E"1a" in this specification) is preferably 7 MPa or less. This configuration is preferred from the viewpoint of excellent transferability of electronic components to the mounting substrate. If E"1a is too high, the adhesion of the electronic component to the first adhesive layer becomes too high, which may impair the transferability when mounting to the mounting substrate. From the viewpoint of transferability of electronic components to the mounting substrate, E"1a is preferably 5 MPa or less, and more preferably 3 MPa or less. If E"1a is too low, the adhesion of the electronic component to the first adhesive layer decreases, which may cause problems such as misalignment or falling of the electronic component. From the viewpoint of adhesion of electronic components to the first adhesive layer, E"1a is preferably 0.01 MPa or more, and more preferably 0.03 MPa or more.

[0014] In the first side transfer double-sided adhesive sheet of the present invention, the tack force of the first adhesive layer against a stainless steel plate (diameter 5 mm) is preferably 10 to 250 gf / Φ5 mm SUS. A configuration in which the tack force is 10 gf / Φ5 mm SUS or more is preferred from the viewpoint of adhesion and positional accuracy of electronic components to the first adhesive layer, and 20 gf / Φ5 mm SUS or more is more preferred. On the other hand, a configuration in which the tack force is 250 gf / Φ5 mm SUS or less is preferred from the viewpoint of transferability of electronic components to the mounting substrate, and 200 gf / Φ5 mm SUS or less is more preferred.

[0015] In the first double-sided adhesive sheet for side transfer of the present invention, the substrate preferably contains a heat-resistant resin. This configuration is preferable because it can prevent transfer defects due to thermal expansion of the substrate when the electronic component received by the first double-sided adhesive sheet for side transfer of the present invention is transferred and mounted onto a mounting substrate by thermocompression. The heat-resistant resin is not particularly limited, but polyimide (PI), polyethylene naphthalate (PEN), polyamide (PA), polyetheretherketone (PEEK), etc. are preferred.

[0016] Furthermore, a second aspect of the present invention provides a method for mounting electronic components onto a mounting substrate. The method of the second aspect of the present invention includes a step (first step) in which the first adhesive layer of the transfer double-sided adhesive sheet of the first aspect of the present invention receives the diced electronic component. In the first step, since the first adhesive layer is composed of a low-tack adhesive layer, it is preferable in that the force applied to the electronic component can be reduced and damage to the electronic component can be suppressed. It is also preferable in that when the electronic component is received by the first adhesive layer without contact, the electronic component is easily caught by the first adhesive layer without bouncing, and can be received with good positional accuracy.

[0017] Furthermore, a second aspect of the present invention includes a step (second step) of transferring the electronic component received by the first adhesive layer to a mounting substrate. In the second step, since the first adhesive layer is composed of a low-tack adhesive layer, it is preferable that the electronic component can be easily peeled off the first adhesive layer when transferring it to the mounting substrate. In the second aspect of the present invention, a semiconductor chip can be suitably used as the electronic component. [Effects of the Invention]

[0018] The double-sided adhesive sheet for transfer according to the present invention allows the first adhesive layer to receive multiple electronic components that have been separated into individual pieces by dicing, eliminating the need to pick them up individually. Furthermore, the electronic components received by the first adhesive layer can be mounted on a large-area circuit board by transferring them all at once, thereby dramatically improving manufacturing efficiency.

[0019] Furthermore, since the first adhesive layer is preferably composed of a low-tack adhesive layer, it is preferable in that it can reduce the force applied to the electronic component and suppress damage to the electronic component. It is also preferable in that when the first adhesive layer receives the electronic component without contact, the electronic component is easily caught by the first adhesive layer without bouncing, and can be received with good positional accuracy. Moreover, since the first adhesive layer is composed of a low-tack adhesive layer, it is preferable in that the electronic component can be easily peeled off the first adhesive layer when transferring the electronic component to the mounting substrate.

[0020] Furthermore, in the double-sided adhesive sheet for transfer of the present invention, since the second adhesive layer is preferably composed of a peelable adhesive layer, the second adhesive layer can be peeled from the carrier substrate without contamination such as adhesive residue, which is preferable in that the reworkability can be improved.

[0021] Therefore, by using the double-sided adhesive sheet for transfer of the present invention for mounting on a mounting substrate of an electronic component, the electronic component can be accurately and efficiently mounted on the mounting substrate.

Brief Description of the Drawings

[0022] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an embodiment of the double-sided adhesive sheet for transfer of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view showing another embodiment of the double-sided adhesive sheet for transfer of the present invention. [Figure 3] FIG. 3 is a schematic cross-sectional view showing an embodiment of the first step in a method for mounting an electronic component on a mounting substrate using the double-sided adhesive sheet for transfer shown in FIG. 1. [Figure 4] FIG. 4 is a schematic cross-sectional view showing an embodiment of the second step in a method for mounting an electronic component on a mounting substrate using the double-sided adhesive sheet for transfer shown in FIG. 1.

Embodiments for Carrying Out the Invention

[0023] [[ID=3२]][Double-sided Adhesive Sheet for Transfer] The double-sided adhesive sheet for transfer of the present invention has a laminated structure in which a first adhesive layer, a base material, and a second adhesive layer are laminated in this order. An embodiment of the double-sided adhesive sheet for transfer of the present invention will be described below with reference to the drawings, but the double-sided adhesive sheet for transfer of the present invention is not limited to the embodiment. FIG. 1 is a schematic cross-sectional view showing an embodiment of the double-sided adhesive sheet for transfer of the present invention, where 1 is the double-sided adhesive sheet for transfer, 10 is the base material, 11 is the first adhesive layer, and 12 is the second adhesive layer.

[0024] As shown in Figure 1, the transfer double-sided adhesive sheet 1 has a laminated structure in which a first adhesive layer 11, a substrate 10, and a second adhesive layer 12 are stacked in this order. When mounting fine, thin electronic components such as semiconductor chips onto a mounting substrate such as a circuit board, the first adhesive layer 11 receives the electronic components. By using the transfer double-sided adhesive sheet 1 for mounting electronic components, the first adhesive layer 11 can receive multiple electronic components that have been separated into individual pieces by dicing all at once, eliminating the need to pick them up individually. Furthermore, the electronic components received by the first adhesive layer 11 can be mounted by transferring them all at once onto a large-area mounting substrate, thereby dramatically improving manufacturing efficiency.

[0025] (1st adhesive layer) In the transfer double-sided adhesive sheet of the present invention, the first adhesive layer is an adhesive layer for receiving and holding electronic components, and is preferably made of a low-tack adhesive layer. The configuration in which the first adhesive layer is made of a low-tack adhesive layer is preferable because it can reduce the force applied to the electronic component when receiving it, thereby suppressing damage to the electronic component. Furthermore, when the first adhesive layer receives an electronic component without contact, for example, the electronic component is peeled off the dicing tape by pressing it with a pin member and dropped onto the first adhesive layer. However, when the first adhesive layer receives the dropped electronic component, it may bounce and not be received accurately. When this phenomenon occurs, the positional accuracy of the electronic product may decrease and contact failure may occur. The configuration in which the first adhesive layer is made of a low-tack adhesive layer is also preferable because when the first adhesive layer receives an electronic component without contact, the electronic component is more likely to be caught by the first adhesive layer without bouncing, and can be received with good positional accuracy. Furthermore, it is preferable because, when the electronic components received by the transfer double-sided adhesive sheet are mounted onto the mounting substrate, the electronic components can be easily peeled off from the first adhesive layer.

[0026] The first adhesive layer can be made into a low-tack adhesive layer by adjusting the type, composition, and degree of crosslinking of the constituent adhesives, or by forming a Weak Boundary Layer (WBL) by incorporating a light release agent or plasticizer.

[0027] The 180° peel-off adhesive strength of the first adhesive layer to the PET film at 25°C is not particularly limited, but from the viewpoint of ensuring that electronic components are received with good positional accuracy without damage and that there is good transferability to the mounting substrate, it is preferably 100mN / 25mm or less, more preferably 50mN / 25mm or less, and even more preferably 10mN / 25mm or less. Furthermore, from the viewpoint of adhesion of electronic components to the first adhesive layer, the 180° peel-off adhesive strength of the first adhesive layer to the glass plate at 25°C is preferably 0.1mN / 25mm or more, and more preferably 1mN / 25mm or more.

[0028] The ratio (P1b / P1a) of the adhesive strength of the first adhesive layer to the PET film at 25°C at 180° peel-off (hereinafter sometimes referred to as "P1a" in this specification) after holding the transfer double-sided adhesive sheet at 160°C for 5 minutes to the adhesive strength of the first adhesive layer to the PET film at 25°C at 180° peel-off (hereinafter sometimes referred to as "P1b" in this specification) to the adhesive strength of the first adhesive layer to the PET film at 25°C at 180° peel-off (hereinafter sometimes referred to as "P1a" in this specification) is not particularly limited, but is preferably 3 or less, and more preferably 2.5 or less. The configuration in which P1b / P1a is 3 or less is preferable because, when the transfer double-sided adhesive sheet of the present invention receives an electronic component and transfers it onto a mounting substrate by thermocompression, the adhesive strength of the first adhesive layer to the electronic component does not increase, and the component can be peeled off well and transferred to the mounting substrate.

[0029] The 180° peel-off adhesive strength at 25°C is measured by laminating the second adhesive layer of the transfer double-sided adhesive sheet to a glass plate, laminating a PET film to the adhesive surface of the first adhesive layer, pressing it with a 2kg roller for one back-and-forth motion, and aging it for 30 minutes in an atmosphere of 23°C and 50%RH. After aging, in accordance with JIS Z 0237, the transfer double-sided adhesive sheet is peeled off the substrate at an atmosphere of 25°C and 50%RH, with a tensile speed of 300mm / min and a peel angle of 180°, and the 180° peel-off adhesive strength (mN / 25mm) is measured. The PET film is not particularly limited as long as it is untreated PET, but an example is the product name "Lumirror #25-S10, thickness 23μm" (manufactured by Toray Industries, Inc.). The adhesive strength of the first adhesive layer can be adjusted by adjusting the type, composition, and degree of crosslinking of the constituent adhesives, or by forming a Weak Boundary Layer (WBL) by incorporating a light release agent or plasticizer.

[0030] In the double-sided adhesive sheet for transfer according to the present invention, the storage modulus (E'1a) of the first adhesive layer at a frequency of 1 Hz and 25°C, measured by AFM-DMA, is preferably 50 MPa or less. This configuration is preferable for ensuring reliable adhesion of electronic components received by the first adhesive layer. If E'1a is too high, the adhesion of electronic components to the first adhesive layer decreases, which may cause problems such as misalignment or falling of electronic components. From the viewpoint of adhesion of electronic components to the first adhesive layer, E'1a is preferably 40 MPa or less, and more preferably 30 MPa or less. It may also be 20 MPa or less, or 10 MPa or less. On the other hand, from the viewpoint of transferability from the first adhesive layer to the circuit board, E'1a is preferably 0.1 MPa or more. If E'1a is too low, the adhesion of electronic components to the first adhesive layer becomes too high, which may impair the transferability when mounting to the mounting substrate. From the viewpoint of transferability of electronic components to the mounting substrate, E'1a is preferably 0.2 MPa or more, and more preferably 0.5 MPa or more.

[0031] In the double-sided adhesive sheet for transfer according to the present invention, the storage modulus (E'1b) of the first adhesive layer at a frequency of 1 kHz and 25°C, as measured by AFM-DMA, is preferably 100 MPa or less. This configuration is preferable because, when the first adhesive layer receives an electronic component without contact, the electronic component is not repelled by the surface of the first adhesive layer and can be received with good positional accuracy. If E'1b is too high, when the electronic component is dropped and received without contact with the surface of the first adhesive layer, the electronic component is likely to be repelled, shift from its predetermined position, or flip over, reducing positional accuracy. From the viewpoint of positional accuracy of the electronic component relative to the first adhesive layer, E'1b is preferably 90 MPa or less, and more preferably 80 MPa or less. It may also be 70 MPa or less, 60 MPa or less, 50 MPa or less, 40 MPa or less, or 30 MPa or less, and particularly may be 20 MPa or less. On the other hand, from the viewpoint of transferability from the first adhesive layer to the mounting substrate, E'1b is preferably 0.5 MPa or more. If E'1b is too low, the adhesion of the electronic component to the first adhesive layer will increase, and the transferability when mounting the electronic component to the mounting substrate may be impaired, such as when the electronic component falls and becomes embedded in the first adhesive layer. From the viewpoint of the transferability of the electronic component to the mounting substrate, E'1b is preferably 0.7 MPa or higher, and more preferably 1 MPa or higher.

[0032] In the double-sided adhesive sheet for transfer according to the present invention, it is preferable that the ratio (E'1b / E'1a) of the storage modulus of the first adhesive layer at a frequency of 1 kHz and 25°C (E'1b) to the storage modulus of the first adhesive layer at a frequency of 1 Hz and 25°C (E'1a) as measured by AFM-DMA of the first adhesive layer is greater than 1. This configuration is preferable because it provides a good balance of adhesion of electronic components to the first adhesive layer, positional accuracy, and transferability to the mounting substrate. From the viewpoint of balancing adhesion of electronic components, positional accuracy, and transferability to the mounting substrate, E'1b / E'1a is preferably 1.05 or higher, and more preferably 1.1 or higher. There is no particular upper limit to E'1b / E'1a, but from the viewpoint of the above balance, it is preferably 3 or lower.

[0033] In the double-sided adhesive sheet for transfer according to the present invention, the loss modulus of elasticity (E”1a) of the first adhesive layer at a frequency of 1 Hz and 25°C, measured by AFM-DMA, is preferably 7 MPa or less. This configuration is preferred from the viewpoint of excellent transferability of electronic components to the mounting substrate. If E”1a is too high, the adhesion of the electronic components to the first adhesive layer becomes too high, which may impair the transferability when mounting to the mounting substrate. From the viewpoint of transferability of electronic components to the mounting substrate, E”1a is preferably 5 MPa or less, and more preferably 3 MPa or less. If E”1a is too low, the adhesion of the electronic components to the first adhesive layer decreases, which may cause problems such as misalignment or falling of the electronic components. From the viewpoint of adhesion of electronic components to the first adhesive layer, E”1a is preferably 0.01 MPa or more, and more preferably 0.03 MPa or more.

[0034] The storage modulus (E'1a) at a frequency of 1 Hz and 25°C, the storage modulus (E'1b) at a frequency of 1 kHz and 25°C, and the loss modulus (E''1a) at a frequency of 1 Hz and 25°C, as measured by AFM-DMA (nano Dynamic Mechanical Analysis (nDMA)) of the first adhesive layer, can be adjusted depending on the type and composition of the adhesive, the degree of crosslinking, etc.

[0035] In the double-sided adhesive sheet for transfer according to the present invention, the tack force of the first adhesive layer against a stainless steel plate (diameter 5 mm) is preferably 10 to 250 gf / Φ5 mm SUS. A configuration in which the tack force is 10 gf / Φ5 mm SUS or more is preferred from the viewpoint of adhesion and positional accuracy of electronic components to the first adhesive layer, and 20 gf / Φ5 mm SUS or more is more preferred. On the other hand, a configuration in which the tack force is 250 gf / Φ5 mm SUS or less is preferred from the viewpoint of transferability of electronic components to the mounting substrate, and 200 gf / Φ5 mm SUS or less is more preferred.

[0036] The tack force of the first adhesive layer against the stainless steel plate (5 mm in diameter) can be adjusted by the type and composition of the adhesive, the degree of crosslinking, and additives such as fatty acid esters and fluorine-based surfactants.

[0037] In the double-sided adhesive sheet for transfer according to the present invention, the surface force of the first adhesive layer is preferably -500 to -100 μN. A configuration in which the surface force is -500 μN or more is preferred from the viewpoint of adhesion and positional accuracy of electronic components to the first adhesive layer, and -400 μN or more is more preferred. On the other hand, a configuration in which the surface force is -100 μN or less is preferred from the viewpoint of transferability of electronic components to the mounting substrate, and -150 μN or less is more preferred.

[0038] The surface force of the first adhesive layer can be adjusted by the type and composition of the adhesive, the degree of crosslinking, and additives such as fatty acid esters and fluorinated surfactants.

[0039] In the double-sided adhesive sheet for transfer of the present invention, the arithmetic mean roughness Ra of the first adhesive layer is preferably 2 nm or less. The configuration in which the arithmetic mean roughness Ra is 2 nm or less is advantageous in that when the first adhesive layer receives an electronic component without contact, the electronic component is easily caught by the first adhesive layer without bouncing, and can be received with good positional accuracy. In terms of the ease with which the electronic component is caught by the first adhesive layer without bouncing and can be received with good positional accuracy, the arithmetic mean roughness Ra is preferably 1.8 nm or less, more preferably 1.5 nm or less, and may be 1.2 nm or less, 1 nm or less, or 0.8 nm or less. The lower limit of the arithmetic mean roughness Ra is not particularly limited, but from the viewpoint of transferability of electronic components to a mounting substrate, it is preferably 0.1 nm or more, and may be 0.2 nm or more, or 0.3 nm or more.

[0040] In the double-sided adhesive sheet for transfer according to the present invention, the absolute value of the ratio of surface force (μN) to the arithmetic mean roughness Ra (nm) of the first adhesive layer (|surface force / Ra;μN / nm|) is preferably 200 or more. The configuration in which the absolute value of the ratio is 200 or more is preferable in that when the first adhesive layer receives an electronic component without contact, the electronic component is easily caught by the first adhesive layer without bouncing and can be received with good positional accuracy. In terms of the ease with which the electronic component is caught by the first adhesive layer without bouncing and can be received with good positional accuracy, the absolute value of the ratio is preferably 225 or more, more preferably 250 or more, and may be 275 or more, or 300 or more. The lower limit of the absolute value of the ratio is not particularly limited, but from the viewpoint of transferability of electronic components to mounting substrates, it is preferably 550 or less, and may be 525 or less, or 500 or less.

[0041] In the double-sided adhesive sheet for transfer according to the present invention, the ten-point average roughness Rz of the first adhesive layer is preferably 15 nm or less. The configuration in which the ten-point average roughness Rz is 15 nm or less is preferable in that when the first adhesive layer receives an electronic component without contact, the electronic component is easily caught by the first adhesive layer without bouncing and can be received with good positional accuracy. In terms of the ease with which the electronic component is caught by the first adhesive layer without bouncing and can be received with good positional accuracy, the ten-point average roughness Rz is preferably 7 nm or less, more preferably 6.8 nm or less, and may be 6.5 nm or less, 5.5 nm or less, or 5 nm or less. The lower limit of the ten-point average roughness Rz is not particularly limited, but from the viewpoint of transferability of electronic components to a mounting substrate, it is preferably 1 nm or more, and may be 2 nm or more, or 3 nm or more.

[0042] In the double-sided adhesive sheet for transfer according to the present invention, the root mean square roughness Rms of the first adhesive layer is preferably 3 nm or less. The configuration in which the root mean square roughness Rms is 3 nm or less is preferable because when the first adhesive layer receives an electronic component without contact, the electronic component is easily caught by the first adhesive layer without bouncing, and can be received with good positional accuracy. In terms of the ease with which the electronic component is caught by the first adhesive layer without bouncing and can be received with good positional accuracy, the root mean square roughness Rms is preferably 1.5 nm or less, more preferably 1.4 nm or less, and may be 1.35 nm or less, 1.3 nm or less, or 1.2 nm or less. The lower limit of the root mean square roughness Rms is not particularly limited, but from the viewpoint of transferability of electronic components to a mounting substrate, it is preferably 0.3 nm or more, and may be 0.4 nm or more, or 0.5 nm or more.

[0043] The surface force, arithmetic mean roughness Ra, ten-point mean roughness Rz, and root mean square roughness Rms of the first adhesive layer can be measured by the method described in the examples below. The arithmetic mean roughness Ra, the ratio of surface force to arithmetic mean roughness Ra, arithmetic mean roughness Ra, ten-point mean roughness Rz, and root mean square roughness Rms of the first adhesive layer can be adjusted by the type and composition of the adhesive, the degree of crosslinking, and additives such as fatty acid esters and fluorinated surfactants.

[0044] In the double-sided adhesive sheet for transfer according to the present invention, the thickness of the first adhesive layer is not particularly limited, but is preferably 1 μm or more, and more preferably 3 μm or more. A thickness above a certain level is preferable because it makes it easier for the first adhesive layer to accurately receive electronic components. Furthermore, the upper limit of the thickness of the first adhesive layer is not particularly limited, but is preferably 100 μm or less, and more preferably 75 μm or less. A thickness below a certain level is preferable because it makes it easier to accurately transfer electronic components to the mounting substrate.

[0045] In the double-sided adhesive sheet for transfer of the present invention, the haze of the first adhesive layer (according to JIS K7136) is not particularly limited, but is preferably 10% or less, and more preferably 5.0% or less. When the haze is 10% or less, excellent transparency is obtained, and for example, when the double-sided adhesive sheet for transfer is attached to a carrier substrate, the pattern attached to the carrier substrate (for example, a marker indicating the transfer position of an electronic component) can be visually confirmed, which is preferable. The haze can be measured, for example, by forming the first adhesive layer on a separator, leaving it to stand at normal conditions (23°C, 50%RH) for at least 24 hours, peeling off the separator, and attaching the sample to a glass slide (for example, one with a total light transmittance of 91.8% and a haze of 0.4%), and using a haze meter (manufactured by Murakami Color Technology Laboratory Co., Ltd., product name "HM-150").

[0046] In the double-sided adhesive sheet for transfer of the present invention, the total light transmittance of the first adhesive layer in the visible light wavelength range (according to JIS K7361-1) is not particularly limited, but is preferably 85% or more, and more preferably 88% or more. A total light transmittance of 85% or more provides excellent transparency, and is preferable because, for example, when the double-sided adhesive sheet for transfer is attached to a carrier substrate, the pattern attached to the carrier substrate (for example, a marker indicating the transfer position of an electronic component) can be visually confirmed. The total light transmittance can be measured, for example, by forming the first adhesive layer on a separator, leaving it at normal conditions (23°C, 50%RH) for at least 24 hours, peeling off the separator, and attaching the sample to a glass slide (for example, one with a total light transmittance of 91.8% and haze of 0.4%), using a haze meter (manufactured by Murakami Color Technology Laboratory Co., Ltd., product name "HM-150").

[0047] The adhesive constituting the first adhesive layer described above is not particularly limited, but examples include silicone-based adhesives, urethane-based adhesives, acrylic-based adhesives, rubber-based adhesives, polyester-based adhesives, polyamide-based adhesives, epoxy-based adhesives, vinyl alkyl ether-based adhesives, and fluorine-based adhesives. Among these, silicone-based adhesives, urethane-based adhesives, and acrylic-based adhesives are preferred, with silicone-based adhesives and urethane-based adhesives being more preferred, and silicone-based adhesives being even more preferred, from the viewpoint of being able to receive electronic components with good positional accuracy without damaging them and further, being able to easily control low tackiness and low adhesiveness to the mounting substrate.

[0048] (Silicone-based adhesive) The silicone adhesive is not particularly limited, and known or conventional silicone adhesives can be used, such as addition-type silicone adhesives, peroxide-curing type silicone adhesives, and condensation-type silicone adhesives. The silicone adhesive may be one-component or two-component. The silicone adhesive can be used alone or in combination of two or more types.

[0049] The aforementioned addition-type silicone adhesives are adhesives that produce a silicone polymer by an addition reaction (hydrosilylation reaction) between an organopolysiloxane having an alkenyl group such as a vinyl group on a silicon atom and an organopolysiloxane having a hydrosilyl group, using a platinum compound catalyst such as chloroplatinic acid. Peroxide-curing type silicone adhesives are adhesives that produce a silicone polymer by curing (crosslinking) an organopolysiloxane with a peroxide. Furthermore, condensation-type silicone adhesives are adhesives that produce a silicone polymer by a dehydration or dealcoholization reaction between polyorganosiloxanes having hydrolyzable silyl groups such as silanol groups or alkoxysilyl groups at their ends.

[0050] Examples of silicone-based adhesives include silicone-based adhesive compositions containing silicone rubber and silicone resin, due to their ease of control over low tackiness and adhesiveness.

[0051] The silicone rubber is not particularly limited as long as it is a silicone-based rubber component, but for example, organopolysiloxanes mainly composed of dimethylsiloxane, methylphenylsiloxane, etc. can be used. Depending on the type of reaction, silicone rubber having alkenyl groups bonded to silicon atoms (alkenyl group-containing organopolysiloxane; in the case of addition reaction), silicone rubber having at least methyl groups (in the case of peroxide curing), and silicone rubber having silanol groups or hydrolyzable alkoxysilyl groups at the ends (in the case of condensation) can be used. The weight-average molecular weight of organopolysiloxane in silicone rubber is usually 150,000 or more, but is preferably 280,000 to 1,000,000, and particularly preferably 500,000 to 900,000.

[0052] Furthermore, the silicone resin is not particularly limited as long as it is a silicone-based resin used in silicone-based adhesives, for example, the constituent unit "R3Si 1 / 2 The M unit consists of the constituent unit "SiO2", the Q unit consists of the constituent unit "RSiO2", and the constituent unit "RSiO 3 / 2Examples include silicone resins made of organopolysiloxanes, which are (co)polymers having at least one unit selected from the T units consisting of "" and the D units consisting of the constituent unit "R2SiO". In the constituent unit, R represents a hydrocarbon group or a hydroxyl group. Examples of the hydrocarbon group include aliphatic hydrocarbon groups (alkyl groups such as methyl and ethyl groups), alicyclic hydrocarbon groups (cycloalkyl groups such as cyclohexyl groups), and aromatic hydrocarbon groups (aryl groups such as phenyl and naphthyl groups). The ratio of the M unit to at least one unit selected from the Q, T, and D units is preferably about 0.3 / 1 to 1.5 / 1 (preferably 0.5 / 1 to 1.3 / 1). Various functional groups such as vinyl groups may be introduced into the organopolysiloxane in such silicone resins as needed. The introduced functional groups may be functional groups capable of crosslinking reactions. As the silicone resin, MQ resin consisting of M units and Q units is preferred. The weight-average molecular weight of the organopolysiloxane in the silicone resin is usually 1000 or more, but is preferably 1000 to 20000, and particularly preferably 1500 to 10000.

[0053] While there are no particular restrictions on the mixing ratio of silicone rubber to silicone resin, it is preferable, for example, that the ratio of silicone resin is 100 to 220 parts by weight (particularly 120 to 180 parts by weight) per 100 parts by weight of silicone rubber, as this makes it easier to control low tackiness and low adhesiveness.

[0054] In a silicone-based adhesive composition containing silicone rubber and silicone resin, the silicone rubber and silicone resin may simply be in a mixed state, or they may react with each other to form condensates (especially partial condensates), crosslinked products, addition reaction products, etc.

[0055] Furthermore, silicone-based adhesive compositions containing silicone rubber and silicone resin typically contain a crosslinking agent to create a crosslinked structure, as this makes it easier to control low tackiness and low adhesiveness. While there are no particular limitations on such crosslinking agents, siloxane-based crosslinking agents (silicone-based crosslinking agents) and peroxide-based crosslinking agents are suitably used. The crosslinking agent can be used alone or in combination of two or more types.

[0056] As the siloxane-based crosslinking agent, for example, a polyorganohydrogensiloxane having two or more hydrogen atoms bonded to silicon atoms in the molecule can be suitably used. In such a polyorganohydrogensiloxane, various organic groups other than hydrogen atoms may be bonded to the silicon atoms to which the hydrogen atoms are bonded. Examples of such organic groups include alkyl groups such as methyl groups and ethyl groups; aryl groups such as phenyl groups; and alkyl halides, but from the viewpoint of synthesis and handling, methyl groups are preferred. Furthermore, the skeletal structure of the polyorganohydrogensiloxane may be linear, branched, or cyclic, but a linear structure is preferred.

[0057] Examples of peroxide-based crosslinking agents include diacyl peroxide, alkyl peroxyester, peroxydicarbonate, monoperoxycarbonate, peroxyketal, dialkyl peroxide, hydroperoxide, and ketone peroxide. More specifically, examples include benzoyl peroxide, t-butyl peroxybenzoate, dicumyl peroxide, t-butylcumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di-t-butyl peroxyhexane, 2,4-dichlorobenzoyl peroxide, di-t-butyl peroxydiisopropylbenzene, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, and 2,5-dimethyl-2,5-di-t-butyl peroxyhexyn-3.

[0058] As addition-curing silicone adhesives, for example, the following are commercially available: product names "KR-3700", "KR-3701", "X-40-3237-1", "X-40-3240", "X-40-3291-1", and "X-40-3306" (all manufactured by Shin-Etsu Chemical Co., Ltd.). In addition, as peroxide-curing silicone adhesives, for example, product names "KR-100", "KR-101-10", and "KR-130" (all manufactured by Shin-Etsu Chemical Co., Ltd.) are commercially available.

[0059] The addition-type silicone adhesive composition preferably contains a curing catalyst such as a platinum catalyst. Examples of commercially available platinum catalysts include "CAT-PL-50T" (manufactured by Shin-Etsu Chemical Co., Ltd.), "DOWSIL NC-25 Catalyst," or "DOWSIL SRX212 Catalyst" (all manufactured by Dow Toray Industries, Inc.). From the viewpoint of balancing the ability of the first adhesive layer to accept electronic components, positional accuracy, transferability to the mounting substrate, and tack strength, the curing catalyst content is preferably about 0.1 to 10 parts by weight per 100 parts by weight of the silicone polymer (including silicone rubber, silicone resin, etc.) as the base polymer.

[0060] (Urethane-based adhesive) The urethane adhesive is not particularly limited, and known or conventional urethane adhesives can be used. However, urethane adhesive compositions containing a polyol, a polyfunctional isocyanate compound, and a catalyst are preferred because they are easy to control to have low tackiness and low adhesiveness.

[0061] As the polyol, any suitable polyol having two or more hydroxyl groups can be used. Examples of such polyols include polyols having two hydroxyl groups (diols), polyols having three hydroxyl groups (triols), polyols having four hydroxyl groups (tetraols), polyols having five hydroxyl groups (pentaols), and polyols having six hydroxyl groups (hexaols). The polyol may be just one type or two or more types.

[0062] The polyol preferably contains a polyol with a number-average molecular weight (Mn) of 400 to 20000. The content of the polyol with a number-average molecular weight (Mn) of 400 to 20000 in the total amount of polyol is preferably 50 to 100% by weight, more preferably 70 to 100% by weight, even more preferably 90 to 100% by weight, particularly preferably 95 to 100% by weight, and most preferably substantially 100% by weight. By adjusting the content of the polyol with a number-average molecular weight (Mn) of 400 to 20000 in the polyol within the above range, for example, a urethane-based adhesive with controlled low tackiness can be provided.

[0063] Examples of the polyols include polyester polyols, polyether polyols, polycaprolactone polyols, polycarbonate polyols, and castor oil-based polyols.

[0064] The aforementioned polyester polyol can be obtained, for example, by an esterification reaction between a polyol component and an acid component.

[0065] Examples of the polyol component include ethylene glycol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, 1,8-decanediol, octadecanediol, glycerin, trimethylolpropane, pentaerythritol, hexanetriol, and polypropylene glycol.

[0066] Examples of the aforementioned acidic components include succinic acid, methylsuccinic acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 1,12-dodecanediic acid, 1,14-tetradecanediic acid, dimer acid, 2-methyl-1,4-cyclohexanedicarboxylic acid, 2-ethyl-1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 4,4'-bifeldicarboxylic acid, and their acid anhydrides.

[0067] Examples of the aforementioned polyether polyols include polyether polyols obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide, using water, low molecular weight polyols (propylene glycol, ethylene glycol, glycerin, trimethylolpropane, pentaerythritol, etc.), bisphenols (bisphenol A, etc.), and dihydroxybenzene (catechol, resorcinol, hydroquinone, etc.) as initiators. Specifically, examples include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

[0068] Examples of the polycaprolactone polyols include caprolactone-based polyester diols obtained by ring-opening polymerization of cyclic ester monomers such as ε-caprolactone and σ-valerolactone.

[0069] Examples of the polycarbonate polyols include: polycarbonate polyols obtained by polycondensation reaction of the polyol component with phosgene; polycarbonate polyols obtained by transesterification condensation of the polyol component with diesters such as dimethyl carbonate, diethyl carbonate, dipropyl carbonate, diisopropyl carbonate, dibutyl carbonate, ethylbutyl carbonate, ethylene carbonate, propylene carbonate, diphenyl carbonate, and dibenzyl carbonate; copolymerized polycarbonate polyols obtained by using two or more of the polyol components in combination; polycarbonate polyols obtained by esterification reaction of the various polycarbonate polyols with carboxyl group-containing compounds; and various Examples include: polycarbonate polyols obtained by etherification reaction of a polycarbonate polyol with a hydroxyl group-containing compound; polycarbonate polyols obtained by transesterification reaction of the aforementioned polycarbonate polyols with ester compounds; polycarbonate polyols obtained by transesterification reaction of the aforementioned polycarbonate polyols with hydroxyl group-containing compounds; polyester-based polycarbonate polyols obtained by polycondensation reaction of the aforementioned polycarbonate polyols with dicarboxylic acid compounds; copolymerized polyether-based polycarbonate polyols obtained by copolymerization of the aforementioned polycarbonate polyols with alkylene oxides; and the like.

[0070] Examples of the castor oil-based polyols include castor oil-based polyols obtained by reacting castor oil fatty acids with the polyol component. Specifically, examples include castor oil-based polyols obtained by reacting castor oil fatty acids with polypropylene glycol.

[0071] As the polyol, it is preferable to use a polyol (triol) having three hydroxyl groups as an essential component, from the viewpoint of low adhesion, low tackiness, and wettability of the first adhesive layer to electronic components. The polyol (triol) having three hydroxyl groups is preferably present in an amount of 50 to 100% by weight, and more preferably 70 to 100% by weight, relative to the total amount of components constituting the polyol.

[0072] Examples of the aforementioned polyfunctional isocyanate compounds include aliphatic polyisocyanates, alicyclic polyisocyanates, and aromatic polyisocyanate compounds.

[0073] Examples of the aliphatic polyisocyanates include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate.

[0074] Examples of the alicyclic polyisocyanates include 1,3-cyclopentene diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate, and hydrogenated tetramethylxylylene diisocyanate.

[0075] Examples of the aromatic polyisocyanates include phenylenediisocyanate, 2,4-tolylenediisosoanate, 2,6-tolylenediisosoanate, 2,2'-diphenylmethanediisocyanate, 4,4'-diphenylmethanediisocyanate, 4,4'-toluidinediisocyanate, 4,4'-diphenyletherdiisocyanate, 4,4'-diphenyldiisocyanate, 1,5-naphthalenediisocyanate, xylylenediisocyanate, and the like.

[0076] Among these, aliphatic polyisocyanates and their modified forms are preferred. Compared to other isocyanate-based crosslinking agents, aliphatic polyisocyanates and their modified forms have a highly flexible crosslinking structure and are easy to control to have low tackiness and low adhesion. Among aliphatic polyisocyanates and their modified forms, hexamethylene diisocyanates and their modified forms are particularly preferred.

[0077] From the viewpoint of low adhesion, low tackiness, and wettability of the first adhesive layer to electronic components, the polyfunctional isocyanate compound and the polyol preferably have an equivalent ratio (NCO / OH) of isocyanate groups of the polyfunctional isocyanate compound and hydroxyl groups of the polyol of 1 to 5, more preferably 1.1 to 3, and even more preferably 1.2 to 2.

[0078] The urethane adhesive composition preferably contains a catalyst such as an iron-based compound and / or a tin-based compound. Specifically, tin-based catalysts such as dibutyltin dilaurate and dioctyltin dilaurate, tris(acetylacetonate) iron, tris(hexane-2,4-dionato) iron, tris(heptane-2,4-dionato) iron, tris(heptane-3,5-dionato) iron, tris(5-methylhexane-2,4-dionato) iron, tris(octane-2,4-dionato) iron, and tris(6-methylheptane-2 ,4-dionato) iron, tris(2,6-dimethylheptane-3,5-dionato) iron, tris(nonane-2,4-dionato) iron, tris(nonane-4,6-dionato) iron, tris(2,2,6,6-tetramethylheptane-3,5-dionato) iron, tris(tridecane-6,8-dionato) iron, tris(1-phenylbutane-1,3-dionato) iron, tris(hexafluoroacetylacetonate Examples of iron-based catalysts include iron, tris(acetate acetate)ferrous iron, tris(acetoacetate-n-propyl)ferrous iron, tris(acetoacetate-isopropyl)ferrous iron, tris(acetoacetate-n-butyl)ferrous iron, tris(acetoacetate-sec-butyl)ferrous iron, tris(acetoacetate-tert-butyl)ferrous iron, tris(propionylacetate-methyl)ferrous iron, tris(propionylacetate-n-propyl)ferrous iron, tris(propionylacetate-isopropyl)ferrous iron, tris(propionylacetate-n-butyl)ferrous iron, tris(propionylacetate-sec-butyl)ferrous iron, tris(propionylacetate-tert-butyl)ferrous iron, tris(acetoacetate benzyl)ferrous iron, tris(malonate dimethyl)ferrous iron, tris(malonate diethyl)ferrous iron, trimethoxyferrous iron, triethoxyferrous iron, triisopropoxyferrous iron, and ferric chloride.

[0079] The amount of catalyst contained in the urethane-based adhesive composition is preferably 0.002 to 0.5 parts by weight, more preferably 0.005 to 0.3 parts by weight, and even more preferably 0.01 to 0.1 parts by weight, per 100 parts by weight of polyol. Within this range, the crosslinking reaction rate is fast when the adhesive layer is formed, and the pot life of the adhesive composition is also extended, resulting in a desirable embodiment.

[0080] Furthermore, as a urethane-based adhesive, a urethane-based adhesive composition containing a urethane prepolymer is also preferred because it is easier to control its low tackiness and low adhesiveness.

[0081] Examples of urethane-based adhesive compositions containing a urethane prepolymer include adhesive compositions containing a polyurethane polyol as the urethane prepolymer and a polyfunctional isocyanate compound. The urethane prepolymer may be one type or two or more types. The polyfunctional isocyanate compound may be one type or two or more types.

[0082] The polyurethane polyol used as a urethane prepolymer is preferably obtained by reacting a polyester polyol and a polyether polyol with an organic polyisocyanate compound in the presence or absence of a catalyst.

[0083] Any suitable polyester polyol can be used as the polyester polyol. Examples of such polyester polyols include those obtained by reacting an acid component with a glycol component. Examples of acid components include terephthalic acid, adipic acid, azelaic acid, sebatic acid, phthalic anhydride, isophthalic acid, and trimellitic acid. Examples of glycol components include ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, 1,6-hexane glycol, 3-methyl-1,5-pentanediol, 3,3'-dimethylolheptane, polyoxyethylene glycol, polyoxypropylene glycol, 1,4-butanediol, neopentyl glycol, and butylethylpentanediol. Examples of polyol components include glycerin, trimethylolpropane, and pentaerythritol. Other examples of polyester polyols include those obtained by ring-opening polymerization of lactones such as polycaprolactone, poly(β-methyl-γ-valerolactone), and polyvalerolactone.

[0084] Polyester polyols can be used with molecular weights ranging from low to high. Preferably, the number average molecular weight of the polyester polyol is 500 to 5000. If the number average molecular weight is less than 500, the reactivity may increase, potentially leading to gelation. If the number average molecular weight exceeds 5000, the reactivity may decrease, and furthermore, the cohesive force of the polyurethane polyol itself may weaken. The amount of polyester polyol used is preferably 10 to 90 mol% of the polyol constituting the polyurethane polyol.

[0085] Any suitable polyether polyol can be used as the polyether polyol. Examples of such polyether polyols include those obtained by polymerizing oxirane compounds such as ethylene oxide, propylene oxide, butylene oxide, and tetrahydrofuran using a low molecular weight polyol such as water, propylene glycol, ethylene glycol, glycerin, or trimethylolpropane as an initiator. Specifically, examples of such polyether polyols include polyether polyols with two or more functional groups, such as polypropylene glycol, polyethylene glycol, and polytetramethylene glycol.

[0086] Polyether polyols can be used with molecular weights ranging from low to high. Preferably, the number average molecular weight of the polyether polyol is between 1000 and 5000. If the number average molecular weight is less than 1000, the reactivity may increase, potentially leading to gelation. If the number average molecular weight exceeds 5000, the reactivity may decrease, and furthermore, the cohesive force of the polyurethane polyol itself may weaken. The amount of polyether polyol used is preferably 20 to 80 mol% of the polyol constituting the polyurethane polyol.

[0087] Polyether polyols can be used in combination with glycols such as ethylene glycol, 1,4-butanediol, neopentyl glycol, butylethylpentanediol, glycerin, trimethylolpropane, and pentaerythritol, or with polyhydric amines such as ethylenediamine, N-aminoethylethanolamine, isophoronediamine, and xylylenediamine, as needed.

[0088] As the polyether polyol, only difunctional polyether polyols may be used, or some or all of a polyether polyol having a number average molecular weight of 1000 to 5000 and at least three hydroxyl groups per molecule may be used. When some or all of a polyether polyol having an average molecular weight of 1000 to 5000 and at least three hydroxyl groups per molecule is used as the polyether polyol, a good balance between adhesiveness and re-peelability can be achieved. In such polyether polyols, if the number average molecular weight is less than 1000, the reactivity may increase, and gelation may become more likely. In such polyether polyols, if the number average molecular weight exceeds 5000, the reactivity may decrease, and furthermore, the cohesive force of the polyurethane polyol itself may decrease. The number average molecular weight of such polyether polyols is more preferably 2500 to 3500.

[0089] Any suitable organic polyisocyanate compound can be used as the organic polyisocyanate compound. Examples of such organic polyisocyanate compounds include aromatic polyisocyanates, aliphatic polyisocyanates, aromatic aliphatic polyisocyanates, and alicyclic polyisocyanates.

[0090] Examples of aromatic polyisocyanates include 1,3-phenylenediisocyanate, 4,4'-diphenyldiisocyanate, 1,4-phenylenediisocyanate, 4,4'-diphenylmethanediisocyanate, 2,4-tolylenediisocyanate, 2,6-tolylenediisocyanate, 4,4'-toluidinediisocyanate, 2,4,6-triisocyanatetoluene, 1,3,5-triisocyanatebenzene, dianisidinediisocyanate, 4,4'-diphenyletherdiisocyanate, and 4,4',4"-triphenylmethanetriisocyanate.

[0091] Examples of aliphatic polyisocyanates include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate.

[0092] Examples of aromatic aliphatic polyisocyanates include ω,ω'-diisocyanate-1,3-dimethylbenzene, ω,ω'-diisocyanate-1,4-dimethylbenzene, ω,ω'-diisocyanate-1,4-diethylbenzene, 1,4-tetramethylxylylenediisocyanate, and 1,3-tetramethylxylylenediisocyanate.

[0093] Examples of alicyclic polyisocyanates include 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate, 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), 1,4-bis(isocyanate methyl)cyclohexane, and 1,4-bis(isocyanate methyl)cyclohexane.

[0094] Organic polyisocyanate compounds such as trimethylolpropane adducts, biuret compounds obtained by reaction with water, and trimers having an isocyanurate ring can also be used in combination.

[0095] Any suitable catalyst can be used to obtain polyurethane polyols. Examples of such catalysts include tertiary amine compounds and organometallic compounds.

[0096] Examples of tertiary amine compounds include triethylamine, triethylenediamine, and 1,8-diazabicyclo(5,4,0)-undecene-7(DBU).

[0097] Examples of organometallic compounds include tin compounds and non-tin compounds.

[0098] Examples of tin-based compounds include dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin dimaleate, dibutyltin dilaurate (DBTDL), dibutyltin diacetate, dibutyltin sulfide, tributyltin sulfide, tributyltin oxide, tributyltin acetate, triethyltin ethoxide, tributyltin ethoxide, dioctyltin oxide, tributyltin chloride, tributyltin trichloroacetate, and tin 2-ethylhexanoate.

[0099] Examples of non-tin compounds include titanium compounds such as dibutyltitanium dichloride, tetrabutyltitanate, and butoxytitanium trichloride; lead compounds such as lead oleate, lead 2-ethylhexanoate, lead benzoate, and lead naphthenate; iron compounds such as iron 2-ethylhexanoate and iron acetylacetonate; cobalt compounds such as cobalt benzoate and cobalt 2-ethylhexanoate; zinc compounds such as zinc naphthenate and zinc 2-ethylhexanoate; and zirconium compounds such as zirconium naphthenate.

[0100] When using a catalyst to obtain polyurethane polyols, systems containing two types of polyols, polyester polyols and polyether polyols, tend to exhibit problems such as gelation and turbidity of the reaction solution due to their differing reactivity when using a single catalyst. Therefore, using two types of catalysts when obtaining polyurethane polyols makes it easier to control the reaction rate and catalyst selectivity, thereby resolving these issues. Examples of such two-catalyst combinations include tertiary amine / organometallic, tin / non-tin, and tin / tin. Preferably, it is tin / tin, and more preferably a combination of dibutyltin dilaurate and tin 2-ethylhexanoate. The weight ratio of tin 2-ethylhexanoate / dibutyltin dilaurate is preferably less than 1, and more preferably 0.2 to 0.6. A ratio of 1 or more may increase the likelihood of gelation due to the balance of catalytic activity.

[0101] When a catalyst is used to obtain polyurethane polyols, the amount of catalyst used is preferably 0.01 to 1.0% by weight relative to the total amount of polyester polyol, polyether polyol, and organic polyisocyanate compound.

[0102] When a catalyst is used to obtain polyurethane polyols, the reaction temperature is preferably less than 100°C, and more preferably 85°C to 95°C. Above 100°C, it may become difficult to control the reaction rate and crosslinking structure, potentially making it difficult to obtain polyurethane polyols with a predetermined molecular weight.

[0103] A catalyst may not be used to obtain polyurethane polyols. In that case, the reaction temperature is preferably 100°C or higher, and more preferably 110°C or higher. Furthermore, when obtaining polyurethane polyols without a catalyst, it is preferable to allow the reaction to proceed for 3 hours or more.

[0104] Methods for obtaining polyurethane polyols include, for example, 1) a method of charging polyester polyol, polyether polyol, catalyst, and organic polyisocyanate into a volumetric flask, and 2) a method of charging polyester polyol, polyether polyol, and catalyst into a flask and adding organic polyisocyanate dropwise. Method 2) is preferred for controlling the reaction when obtaining polyurethane polyols.

[0105] Any suitable solvent can be used to obtain polyurethane polyols. Examples of such solvents include methyl ethyl ketone, ethyl acetate, toluene, xylene, and acetone. Among these solvents, toluene is preferred.

[0106] As polyfunctional isocyanate compounds, those mentioned above can be used.

[0107] As a method for producing a polyurethane-based composition obtained from a composition containing a urethane prepolymer, any suitable manufacturing method can be adopted, as long as it is a method of producing a polyurethane-based resin composition using a so-called "urethane prepolymer" as a raw material.

[0108] (Acrylic adhesive) The acrylic adhesive is not particularly limited, and known or conventional acrylic adhesives can be used. For example, an acrylic adhesive composition containing an acrylic polymer as a base polymer is recommended because it is easy to control low tackiness and low adhesiveness.

[0109] The above-mentioned acrylic polymer is a polymer that contains structural units derived from acrylic monomers (monomer components having a (meth)acryloyl group in the molecule) as polymer structural units. Preferably, the above-mentioned acrylic polymer is a polymer that contains the largest mass percentage of structural units derived from (meth)acrylic acid esters. Note that only one type of acrylic polymer may be used, or two or more types may be used. In this specification, "(meth)acrylic" means "acrylic" and / or "methacrylic" (either one or both of "acrylic" and "methacrylic"), and the same applies elsewhere.

[0110] Examples of the above (meth)acrylic acid esters include hydrocarbon group-containing (meth)acrylic acid esters. Examples of hydrocarbon group-containing (meth)acrylic acid esters include (meth)acrylic acid alkyl esters, (meth)acrylic acid cycloalkyl esters, and (meth)acrylic acid aryl esters. Examples of the above (meth)acrylic acid alkyl esters include (meth)acrylic acid methyl ester, ethyl ester, propyl ester, isopropyl ester, butyl ester, isobutyl ester, s-butyl ester, t-butyl ester, pentyl ester, isopentyl ester, hexyl ester, heptyl ester, octyl ester, 2-ethylhexyl ester, isooctyl ester, nonyl ester, decyl ester, isodecyl ester, undecyl ester, dodecyl ester (lauryl ester), tridecyl ester, tetradecyl ester, hexadecyl ester, octadecyl ester, and eicosyl ester. Examples of the above (meth)acrylic acid cycloalkyl esters include (meth)acrylic acid cyclopentyl ester and cyclohexyl ester. Examples of the above-mentioned aryl (meth)acrylate esters include phenyl esters and benzyl esters of (meth)acrylic acid.

[0111] The hydrocarbon group-containing (meth)acrylic acid ester described above may be used by one type or by two or more types. To appropriately exhibit the basic properties such as tackiness due to the hydrocarbon group-containing (meth)acrylic acid ester in the first adhesive layer, and to easily control low tackiness and low adhesiveness, the proportion of hydrocarbon group-containing (meth)acrylic acid ester in the total monomer components for forming the acrylic polymer is preferably 40% by mass or more, and more preferably 60% by mass or more.

[0112] The above acrylic polymer may contain constituent units derived from other monomer components copolymerizable with the hydrocarbon group-containing (meth)acrylic acid ester for the purpose of modifying properties such as cohesiveness, heat resistance, tackiness, etc. Examples of the above other monomer components include carboxyl group-containing monomers, acid anhydride monomers, hydroxyl group-containing monomers, glycidyl group-containing monomers, sulfonic acid group-containing monomers, phosphate group-containing monomers, acrylamide, acrylonitrile and other functional group-containing monomers, vinyl ester monomers, etc. Examples of the above carboxyl group-containing monomers include acrylic acid, methacrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, etc. Examples of the above acid anhydride monomers include maleic anhydride, itaconic anhydride, etc. Examples of the above hydroxyl group-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl (meth)acrylate. Examples of the above glycidyl group-containing monomers include glycidyl (meth)acrylate and methylglycidyl (meth)acrylate. Examples of the above sulfonic acid group-containing monomers include styrene sulfonic acid, allyl sulfonic acid, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamidepropanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acryloyloxynaphthalenesulfonic acid. Examples of the above phosphate group-containing monomers include 2-hydroxyethyl acryloyl phosphate. Examples of the vinyl ester monomers mentioned above include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl pivalate, vinyl cyclohexanecarboxylate, and vinyl benzoate. Only one of the above-mentioned other monomer components may be used, or two or more may be used.To appropriately exhibit basic properties such as tackiness due to hydrocarbon group-containing (meth)acrylic acid esters in the first adhesive layer, and to easily control low tackiness and low adhesiveness, the total proportion of the above-mentioned other monomer components in the total monomer components for forming the acrylic polymer is preferably 60% by mass or less, and more preferably 40% by mass or less.

[0113] The above-mentioned acrylic polymer may contain constituent units derived from polyfunctional monomers copolymerizable with monomer components that form the acrylic polymer, in order to form a crosslinked structure within its polymer backbone. Examples of the above-mentioned polyfunctional monomers include monomers having a (meth)acryloyl group and other reactive functional groups in the molecule, such as hexanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, epoxy(meth)acrylate (e.g., polyglycidyl(meth)acrylate), polyester(meth)acrylate, and urethane(meth)acrylate. Only one of the above-mentioned polyfunctional monomers may be used, or two or more may be used. To appropriately exhibit basic properties such as tackiness due to hydrocarbon group-containing (meth)acrylic acid esters in the first adhesive layer, and to easily control low tackiness and low adhesiveness, the proportion of the above-mentioned polyfunctional monomer in the total monomer components for forming the acrylic polymer is preferably 40% by mass or less, and more preferably 30% by mass or less.

[0114] Acrylic polymers are obtained by polymerizing one or more monomer components, including acrylic monomers. Polymerization methods include solution polymerization, emulsion polymerization, bulk polymerization, and suspension polymerization.

[0115] The mass-average molecular weight of the acrylic polymer is preferably 100,000 or more, and more preferably 200,000 to 3,000,000. When the mass-average molecular weight is 100,000 or more, there tends to be less low molecular weight material in the adhesive layer, which can further suppress contamination of electronic components and the like.

[0116] The acrylic adhesive composition forming the first adhesive layer may contain a crosslinking agent. For example, the acrylic polymer can be crosslinked to further reduce the amount of low molecular weight substances in the first adhesive layer. Furthermore, the mass-average molecular weight of the acrylic polymer can be increased, allowing for control of low tackiness and low adhesiveness. Examples of the crosslinking agent include polyisocyanate compounds, epoxy compounds, polyol compounds (such as polyphenol compounds), aziridine compounds, and melamine compounds, with isocyanate-based crosslinking agents and / or epoxy-based crosslinking agents being preferred. When using a crosslinking agent, the amount used is preferably about 10 parts by mass or less, and more preferably 0.1 to 10 parts by mass, per 100 parts by mass of the acrylic polymer.

[0117] Examples of isocyanate crosslinking agents include aliphatic isocyanates, alicyclic isocyanates, and aromatic isocyanates. Examples of aliphatic isocyanates include trimethylene diisocyanate, butylene diisocyanate, hexamethylene diisocyanate, and dimer acid diisocyanate. Examples of alicyclic isocyanates include cyclopentylene diisocyanate, cyclohexylene diisocyanate, isophorone diisocyanate, and 1,3-bis(isocyanatomethyl)cyclohexane. Examples of aromatic isocyanates include 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and xylylene diisocyanate. Other examples of isocyanate-based crosslinking agents include the trimethylolpropane adduct of tolylene diisocyanate (product name "Coronate L", manufactured by Tosoh Corporation) and the isocyanurate derivative of hexamethylene diisocyanate (product name "Coronate HX", manufactured by Tosoh Corporation).

[0118] Examples of epoxy crosslinking agents (polyfunctional epoxy compounds) include N,N,N',N'-tetraglycidyl-m-xylenediamine, diglycidylaniline, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and sorbitol polyglycidyl ether. Examples include diglycidyl ether, glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, diglycidyl adipate ester, diglycidyl o-phthalate ester, triglycidyl-tris(2-hydroxyethyl) isocyanurate, resorcinol diglycidyl ether, and bisphenol-S-diglycidyl ether. Epoxy resins having two or more epoxy groups in their molecules are also included. A commercially available epoxy crosslinking agent is, for example, "Tetrad C" manufactured by Mitsubishi Gas Chemical Company, Inc.

[0119] The adhesive composition constituting the first adhesive layer preferably contains a light release agent. By including a light release agent, a Weak Boundary Layer (WBL) is formed on the surface of the first adhesive layer, making it easier to control low tackiness and low adhesiveness.

[0120] The light stripping agent is not particularly limited, and any known light stripping agent can be used without restriction. Examples include silicone-based stripping agents, fluorine-based surfactants, and aliphatic esters, which can be used individually or in combination of two or more.

[0121] The above-mentioned silicone-based release agent is not particularly limited, but examples include thermosetting silicone-based release agents and ionizing radiation-curable silicone-based release agents. Furthermore, the silicone-based release agent may be either a solvent-free type that does not contain a solvent, or a solvent-based type that is dissolved or dispersed in an organic solvent. The silicone-based release agent can be used alone or in combination of two or more types.

[0122] The above-mentioned thermosetting silicone-based release agent is not particularly limited, but it is preferable that it contains an organohydrogenpolysiloxane and an organopolysiloxane having an aliphatic unsaturated group. Furthermore, it is preferable that the above-mentioned silicone-based release agent is a thermoaddition reaction curable silicone-based release agent that hardens by crosslinking due to a thermal addition reaction.

[0123] The above-mentioned heat-curable silicone-based release agent is not particularly limited, but preferably includes a polysiloxane having hydrogen atoms (H) bonded to silicon atoms (Si) in its molecule (Si-H group-containing polysiloxane) and a polysiloxane containing a functional group that is reactive to Si-H bonds (Si-H group-reactive functional group) in its molecule (Si-H group-reactive polysiloxane). This release agent hardens by crosslinking through an addition reaction between the Si-H group and the Si-H group-reactive functional group.

[0124] In the above Si-H group-containing polysiloxane, the Si to which H is bonded may be either Si in the main chain or Si in the side chain. The above Si-H group-containing polysiloxane is preferably a polysiloxane containing two or more Si-H groups in its molecule. Examples of polysiloxanes containing two or more Si-H groups include dimethylhydrogensiloxane polymers such as poly(dimethylsiloxane-methylsiloxane).

[0125] Furthermore, as the Si-H group reactive polysiloxane described above, polysiloxanes in which a Si-H group reactive functional group or a side chain containing such a functional group is bonded to Si (for example, Si at the ends of the main chain, Si inside the main chain) that forms the main chain (backbone) of the siloxane polymer are preferred. Among these, polysiloxanes in which the Si-H group reactive functional group is directly bonded to Si in the main chain are preferred. Moreover, as the Si-H group reactive polysiloxane described above, polysiloxanes containing two or more Si-H group reactive functional groups in the molecule are also preferred.

[0126] Examples of Si-H group reactive functional groups in the above-mentioned Si-H group reactive polysiloxane include vinyl groups, alkenyl groups such as hexenyl groups, and so on. Examples of siloxane polymers that form the main chain portion of the above-mentioned Si-H group reactive polysiloxane include polydialkylsiloxanes such as polydimethylsiloxane, polydiethylsiloxane, and polymethylethylsiloxane (the two alkyl groups may be the same or different); polyalkylarylsiloxanes; poly(dimethylsiloxane-methylsiloxane); polymers obtained by polymerizing multiple Si-containing monomers, and so on. Among these, polydimethylsiloxane is preferred as the siloxane polymer that forms the main chain portion.

[0127] In particular, the above-mentioned thermo-curable silicone-based release agent is preferably a thermo-curable silicone-based release agent that contains a polysiloxane containing two or more Si-H groups in its molecule and a polysiloxane containing two or more Si-H group-reactive functional groups in its molecule.

[0128] Furthermore, while the above-mentioned ionizing radiation-curable silicone-based release agent is not particularly limited, UV-curable silicone-based release agents that undergo a crosslinking reaction and harden upon ultraviolet (UV) irradiation are preferred.

[0129] The above UV-curable silicone-based release agent is a release agent that hardens upon UV irradiation through chemical reactions such as cationic polymerization, radical polymerization, radical addition polymerization, and hydrosilylation. A UV-curable silicone-based release agent that hardens by cationic polymerization is particularly preferred.

[0130] While not particularly limited, a preferred release agent is an epoxy group-containing polysiloxane in which at least two epoxy groups are bonded directly or via divalent groups (alkylene groups such as methylene groups and ethylene groups; alkylene oxygen groups such as ethylene oxygen groups and propylene oxygen groups) to Si forming the main chain (skeleton) of a siloxane polymer (e.g., Si at the ends of the main chain, Si inside the main chain) and / or Si included in the side chains. The manner in which these at least two epoxy groups are bonded to Si may be the same or different. That is, a preferred release agent is an epoxy group-containing polysiloxane containing two or more epoxy group-containing side chains of one or more types. Examples of epoxy group-containing side chains include glycidyl groups, glycidoxy groups (glycidyl oxy groups), 3,4-epoxycyclohexyl groups, and 2,3-epoxycyclopentyl groups. The epoxy group-containing polysiloxane may be linear, branched, or a mixture thereof.

[0131] In particular, in the double-sided adhesive tape for transfer of the present invention, from the viewpoint of easily controlling the first adhesive layer to have low tackiness and low adhesiveness, it is preferable that the silicone-based adhesive contains a thermosetting silicone-based release agent, and more preferably that it contains a thermoaddition reaction curable silicone-based release agent.

[0132] When the first adhesive layer of the transfer double-sided adhesive tape of the present invention contains a silicone-based adhesive, the content of the silicone-based release agent is not particularly limited, but is preferably 0.5 parts by weight or more and 100 parts by weight or less per 100 parts by weight of the silicone-based polymer, which is the base polymer. When the content is 0.5 parts by weight or more, it is easier to obtain the effect of controlling the first adhesive layer to have low tackiness and low adhesiveness, and is more preferably 1 part by weight or more, and even more preferably 3 parts by weight or more. Furthermore, when the content is 100 parts by weight or less, it is easier to suppress the problem of insufficient adhesiveness being obtained, making it difficult to receive electronic components, and is more preferably 30 parts by weight or less, and even more preferably 25 parts by weight or less.

[0133] By using the aforementioned fluorine-based surfactant as a mild peeling agent, a mild peeling effect can be achieved due to the low surface free energy of the fluorine portion.

[0134] The above-mentioned fluorinated surfactants are not particularly limited, but examples include fluorinated oligomers, perfluorobutanesulfonates, perfluoroalkyl group-containing carboxylates, hexafluoropentane trimer derivative-containing sulfonates, hexafluoropentane trimer derivative-containing carboxylates, hexafluoropentane trimer derivative-containing quaternary ammonium salts, hexafluoropentane trimer derivative-containing betaines, hexafluoropentane trimer derivative-containing polyoxyethylene ethers, and so on, with fluorinated oligomers being preferred. The fluorinated surfactants can be used alone or in combination of two or more types.

[0135] Specific examples of the aforementioned fluorine-based surfactants include, for example, commercially available products with product names such as Megafac F-114, F-410 (both manufactured by DIC Corporation), Surflon S-211, S-221, S-231, S-232, S-233, S-241, S-242, S-243, S-420 (all manufactured by AGC Seimi Chemical Co., Ltd.), and Futergent 100, 100C, 110, 150, 150CH, 300, 310, 320, 400SW, 251, 212M, 215M, 250, 209F, 222F, 245F, 208G, 218GL, 240G, 212P, 220P, 228P, FTX-218, DFX-18 (all manufactured by Neos Corporation). These compounds may be used individually or in combination of two or more.

[0136] The weight-average molecular weight (Mw) of the fluorine-based oligomer is preferably 3500 or more, more preferably 5000 or more, even more preferably 10000 or more, and particularly preferably 20000 or more. When the weight-average molecular weight of the fluorine-based oligomer is 3500 or more, it becomes easier to control low tackiness and low adhesiveness. Furthermore, when the weight-average molecular weight is 20000 or more, foaming during the formulation of the adhesive (composition) can be suppressed, and the appearance after adhesive coating is excellent, which is preferable. In addition, the upper limit of the weight-average molecular weight (Mw) of the fluorine-based oligomer is preferably 200,000 or less, and more preferably 100,000 or less. Setting it to 200,000 or less makes it easier for the fluorine-based oligomer to be unevenly distributed on the surface, which is preferable as it makes it easier to exhibit a light peeling effect.

[0137] Furthermore, as for the fluorine-based oligomers, for example, commercially available products with product names such as Megafack F-251, F-253, F-281, F-410, F-430, F-444, F-477, F-510, F-511, F-551, F-552, F-553, F-554, F-555, F-556, F-557, F-558, F-559, F-560, and F-56 Examples include F-562, F-563, F-565, F-568, F-569, F-570, F-571, F-572 (all manufactured by DIC Corporation), Surflon S-611, S-651, S-386 (all manufactured by AGC Seimi Chemical Co., Ltd.), and Futergent 610FM, 710FL, 710FM, 710FS, 730FL, 730LM (all manufactured by Neos Corporation). These compounds may be used individually or in combination of two or more.

[0138] When the first adhesive layer of the transfer double-sided adhesive tape of the present invention contains a fluorine-based surfactant, the content of the fluorine-based surfactant is not particularly limited, but is preferably 0.01 parts by weight or more and 5 parts by weight or less per 100 parts by weight of the silicone-based polymer, which is the base polymer. When the content is 0.01 parts by weight or more, it is easier to obtain the effect of controlling the first adhesive layer to have low tackiness and low adhesiveness, and is more preferably 0.05 parts by weight or more, and even more preferably 0.1 parts by weight or more. Furthermore, when the content is 5 parts by weight or less, it is easier to suppress the problem of insufficient adhesiveness and difficulty in receiving electronic components, and from the viewpoint of suppressing a decrease in transparency, it is more preferably 3 parts by weight or less, and even more preferably 2 parts by weight or less.

[0139] By including a fatty acid ester in the adhesive composition constituting the first adhesive layer, low tackiness, low adhesion, and wettability of the first adhesive layer to electronic components can be expected.

[0140] Examples of the aforementioned fatty acid esters include polyoxyethylene bisphenol A laurate, butyl stearate, 2-ethylhexyl palmitate, 2-ethylhexyl stearate, monoglyceride behenate, cetyl 2-ethylhexanoate, isopropyl myristate, isopropyl palmitate, cholesteryl isostearate, lauryl methacrylate, methyl coconut fatty acid, methyl laurate, methyl oleate, methyl stearate, myristyl myristate, octyldodecyl myristate, pentaerythritol monooleate, pentaerythritol monostearate, pentaerythritol tetrapalmitate, stearyl stearate, isotridecyl stearate, triglyceride 2-ethylhexanoate, butyl laurate, octyl oleate, and tridecyl isononanoate. The fatty acid ester may be one type or two or more types.

[0141] The amount of fatty acid ester contained in the urethane-based adhesive composition is preferably 1 to 50 parts by weight, more preferably 2 to 40 parts by weight, and even more preferably 3 to 30 parts by weight, per 100 parts by weight of polyol, from the viewpoint of low tackiness, low wettability, and staining of the adherend of the first adhesive layer to electronic components.

[0142] If the adhesive composition constituting the first adhesive layer contains a light release agent, the content (total amount) thereof is preferably 0.1 parts by weight or more, more preferably 1 part by weight or more, and even more preferably 3 parts by weight or more, per 100 parts by weight of the base polymer, from the viewpoint of low adhesion, low tack, wettability, and contamination of electronic components of the first adhesive layer. From the viewpoint of preventing discoloration of the first adhesive layer, it is preferably 50 parts by weight or less, more preferably 30 parts by weight or less, and even more preferably 10 parts by weight or less.

[0143] The adhesive composition constituting the first adhesive layer preferably contains degradation inhibitors such as antioxidants and ultraviolet absorbers. By including degradation inhibitors, degradation such as discoloration during storage of the double-sided adhesive sheet for transfer of the present invention can be suppressed, and the processability of the double-sided adhesive sheet for transfer can be improved, such as making it easier to cut.

[0144] The UV absorber is not particularly limited, but examples include triazine-based UV absorbers, benzotriazole-based UV absorbers, benzophenone-based UV absorbers, oxybenzophenone-based UV absorbers, salicylic acid ester-based UV absorbers, and cyanoacrylate-based UV absorbers, and these can be used individually or in combination of two or more. Among these, triazine-based UV absorbers and benzotriazole-based UV absorbers are preferred, and it is preferable that at least one UV absorber is selected from the group consisting of triazine-based UV absorbers having two or fewer hydroxyl groups in one molecule and benzotriazole-based UV absorbers having one benzotriazole skeleton in one molecule, because they have good solubility in monomers used to form acrylic adhesive compositions and have high UV absorption capacity around a wavelength of 380 nm.

[0145] Triazine-based UV absorbers having two or fewer hydroxyl groups in one molecule include, specifically, 2,4-bis-[{4-(4-ethylhexyloxy)-4-hydroxy}-phenyl]-6-(4-methoxyphenyl)-1,3,5-triazine (Tinosorb S, manufactured by BASF), 2,4-bis[2-hydroxy-4-butoxyphenyl]-6-(2,4-dibutoxyphenyl)-1,3,5-triazine (TINUVIN 460, manufactured by BASF), and 2-(4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine-2-yl)-5-hydroxyphenyl and [(C 10 -C 16 (mainly C 12 -C 13Reaction product with alkyloxy)methyl]oxirane (TINUVIN400, BASF), 2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine-2-yl]-5-[3-(dodecyloxy)-2-hydroxypropoxy]phenol), reaction product of 2-(2,4-dihydroxyphenyl)-4,6-bis-(2,4-dimethylphenyl)-1,3,5-triazine and (2-ethylhexyl)-glycidic acid ester (TINUVIN405, BASF), 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-[(hexyl)oxy]-phenol (TINUVIN1577, BASF), 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-[2-(2-ethylhexanoyloxy)ethoxy]-phenol (ADK STAB Examples include LA46 (manufactured by ADEKA) and 2-(2-hydroxy-4-[1-octyloxycarbonylethoxy]phenyl)-4,6-bis(4-phenylphenyl)-1,3,5-triazine (TINUVIN479, manufactured by BASF).

[0146] Furthermore, examples of benzotriazole-based UV absorbers having one benzotriazole skeleton in one molecule include 2-(2H-benzotriazole-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol (TINUVIN 928, manufactured by BASF), 2-(2-hydroxy-5-tert-butylphenyl)-2H-benzotriazole (TINUVIN PS, manufactured by BASF), benzenepropanoic acid, and 3-(2H-benzotriazole-2-yl)-5-(1,1-dimethylethyl)-4-hydroxy(C 7-9Ester compounds of side chains and linear alkyls (TINUVIN384-2, BASF), 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (TINUVIN900, BASF), 2-(2H-benzotriazol-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol (TINUVIN928, BASF), reaction product of methyl-3-(3-(2H-benzotriazol-2-yl)-5-t-butyl-4-hydroxyphenyl)propionate / polyethylene glycol 300 (TINUVIN1130, BASF), 2-(2H-benzotriazol-2-yl)-p-cresol (TINUVIN P (manufactured by BASF), 2(2H-benzotriazol-2-yl)-4-6-bis(1-methyl-1-phenylethyl)phenol (TINUVIN234, manufactured by BASF), 2-[5-chloro(2H)-benzotriazol-2-yl]-4-methyl-6-(tert-butyl)phenol (TINUVIN326, manufactured by BASF), 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol (TINUVIN328, manufactured by BASF), 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol (TINUVIN234, manufactured by BASF). Examples include N329 (manufactured by BASF), reaction product of methyl 3-(3-(2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyphenyl)propionate and polyethylene glycol 300 (TINUVIN 213, manufactured by BASF), 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol (TINUVIN 571, manufactured by BASF), and 2-[2-hydroxy-3-(3,4,5,6-tetrahydrophthalimidomethyl)-5-methylphenyl]benzotriazole (Sumisorb 250, manufactured by Sumitomo Chemical Co., Ltd.).

[0147] Furthermore, examples of the benzophenone-based ultraviolet absorbers (benzophenone compounds) and oxybenzophenone-based ultraviolet absorbers (oxybenzophenone compounds) include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid (anhydrous and trihydrate), 2-hydroxy-4-octyloxybenzophenone, 4-dodecyloxy-2-hydroxybenzophenone, 4-benzyloxy-2-hydroxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, and 2,2'-dihydroxy-4,4-dimethoxybenzophenone.

[0148] Examples of the salicylic acid ester-based ultraviolet absorbers (salicylic acid ester compounds) include phenyl-2-acryloyloxybenzoate, phenyl-2-acryloyloxy-3-methylbenzoate, phenyl-2-acryloyloxy-4-methylbenzoate, phenyl-2-acryloyloxy-5-methylbenzoate, phenyl-2-acryloyloxy-3-methoxybenzoate, phenyl-2-hydroxybenzoate, phenyl-2-hydroxy-3-methylbenzoate, phenyl-2-hydroxy-4-methylbenzoate, phenyl-2-hydroxy-5-methylbenzoate, phenyl-2-hydroxy-3-methoxybenzoate, and 2,4-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate (TINUVIN120, manufactured by BASF).

[0149] Examples of the cyanoacrylate-based ultraviolet absorbers (cyanoacrylate compounds) include alkyl-2-cyanoacrylate, cycloalkyl-2-cyanoacrylate, alkoxyalkyl-2-cyanoacrylate, alkenyl-2-cyanoacrylate, and alkynyl-2-cyanoacrylate.

[0150] The maximum absorption wavelength in the absorption spectrum of the UV absorber is preferably in the wavelength region of 300 to 400 nm, and more preferably in the wavelength region of 320 to 380 nm.

[0151] Examples of the aforementioned antioxidants include phenolic, phosphorus-based, sulfur-based, and amine-based antioxidants, and at least one selected from these is used. Among these, phenolic antioxidants are preferred, and hindered phenolic antioxidants are particularly preferred.

[0152] Specific examples of phenolic antioxidants include monocyclic phenol compounds such as 2,6-di-t-butyl-p-cresol, 2,6-di-t-butyl-4-ethylphenol, 2,6-dicyclohexyl-4-methylphenol, 2,6-diisopropyl-4-ethylphenol, 2,6-di-t-amyl-4-methylphenol, 2,6-di-t-octyl-4-n-propylphenol, 2,6-dicyclohexyl-4-n-octylphenol, 2-isopropyl-4-methyl-6-t-butylphenol, 2-t-butyl-4-ethyl-6-t-octylphenol, 2-isobutyl-4-ethyl-6-t-hexylphenol, 2-cyclohexyl-4-n-butyl-6-isopropylphenol, styrene-mixed cresol, DL-α-tocopherol, and stearyl β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, which are bicyclic phenolic compounds. Examples of phenolic compounds include 2,2'-methylenebis(4-methyl-6-t-butylphenol), 4,4'-butylidenebis(3-methyl-6-t-butylphenol), 4,4'-thiobis(3-methyl-6-t-butylphenol), 2,2'-thiobis(4-methyl-6-t-butylphenol), 4,4'-methylenebis(2,6-di-t-butylphenol), and 2,2'-methylenebis[6-(1-methylcyclohexyl )-p-cresol], 2,2'-ethylidenebis(4,6-di-t-butylphenol), 2,2'-butylidenebis(2-t-butyl-4-methylphenol), 3,6-dioxaoctamethylenebis[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionate], triethylene glycol bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], 1,6-hexanediol Bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 2,2'-thiodiethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], etc., as tri-ring phenol compounds, 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-tris(2,6-dimethyl-3-hydroxy-4-t-butylbenzyl)isocyanurate, 1,3,5-tris[(3,Examples of tetracyclic phenolic compounds include 5-di-t-butyl-4-hydroxyphenyl)propionyloxyethyl isocyanurate, tris(4-t-butyl-2,6-dimethyl-3-hydroxybenzyl)isocyanurate, and 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene; tetracyclic phenolic compounds include tetrakis[methylene-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]methane; and phosphorus-containing phenolic compounds include bis(3,5-di-t-butyl-4-hydroxybenzylphosphonate ethyl)calcium and bis(3,5-di-t-butyl-4-hydroxybenzylphosphonate ethyl)nickel.

[0153] The aforementioned degradation inhibitor may be used alone or in a mixture of two or more types. From the viewpoint of suppressing degradation such as discoloration during storage and the processability of the double-sided adhesive sheet for transfer, the amount of degradation inhibitor contained in the adhesive composition is preferably 0.01 to 10 parts by weight, more preferably 0.03 to 5 parts by weight, and even more preferably 0.1 to 3 parts by weight per 100 parts by weight of the adhesive composition.

[0154] The adhesive composition constituting the first adhesive layer may contain any other suitable components as long as they do not impair the effects of the present invention. Examples of such other components include tackifiers, inorganic fillers, organic fillers, metal powders, pigments, foils, softeners, plasticizers, conductive agents, surface lubricants, leveling agents, heat stabilizers, polymerization inhibitors, lubricants, solvents, and the like.

[0155] (Second adhesive layer) In the transfer double-sided adhesive sheet of the present invention, the second adhesive layer is an adhesive layer for temporary fixing to a carrier substrate, and is preferably made of a release adhesive layer. The configuration in which the second adhesive layer is made of a release adhesive layer is preferable because the second adhesive layer can be peeled off from the carrier substrate without contamination such as adhesive residue, thereby improving reworkability. The second adhesive layer can be made into a release adhesive layer by adjusting its tackiness through the type and composition of the adhesive, the degree of crosslinking, etc., or by reducing its tackiness through physical stimuli such as heat, ultraviolet rays, or other electromagnetic waves.

[0156] The 180° peel-off adhesive strength of the second adhesive layer to the glass plate at 25°C is not particularly limited, but it is preferably 5000mN / 25mm or less, more preferably 3000mN / 25mm or less, and even more preferably 1000mN / 25mm or less, from the viewpoint of being able to peel it off from the carrier substrate without contamination such as adhesive residue, and from the viewpoint of improving reworkability. Furthermore, from the viewpoint of adhesion of the carrier substrate to the second adhesive layer, the 180° peel-off adhesive strength of the second adhesive layer to the glass plate at 25°C is preferably 1mN / 25mm or more, and more preferably 5mN / 25mm or more.

[0157] The ratio (P2b / P2a) of the adhesion strength of the second adhesive layer to the glass plate at 25°C when peeled off at 180°C (hereinafter sometimes referred to as "P2a" in this specification) after holding the transfer double-sided adhesive sheet at 160°C for 5 minutes to the adhesion strength of the second adhesive layer to the glass plate at 25°C when peeled off at 180°C (hereinafter sometimes referred to as "P2b" in this specification) to the adhesion strength of the second adhesive layer to the glass plate at 25°C when peeled off at 180°C (hereinafter sometimes referred to as "P2a" in this specification) is not particularly limited, but is preferably 2 or less, and more preferably 2.5 or less. The configuration in which P2b / P2a is 3 or less is preferable because, when the transfer double-sided adhesive sheet of the present invention receives an electronic component and transfers it onto the mounting substrate by thermocompression bonding, the adhesion strength of the second adhesive layer to the carrier substrate does not increase, and it peels off well, resulting in excellent reworkability.

[0158] The 180° peel-off adhesive strength of the second adhesive layer at 25°C can be measured in the same manner as the first adhesive layer. The adhesive strength of the second adhesive layer can be adjusted by adjusting the type, composition, and degree of crosslinking of the constituent adhesives, or by forming a Weak Boundary Layer (WBL) by incorporating a light release agent or plasticizer.

[0159] In the double-sided adhesive sheet for transfer according to the present invention, the thickness of the second adhesive layer is not particularly limited, but is preferably 1 μm or more, and more preferably 3 μm or more. A thickness above a certain level is preferable because it makes it easier for the second adhesive layer to be stably fixed to the carrier substrate. Furthermore, the upper limit of the thickness of the second adhesive layer is not particularly limited, but is preferably 30 μm or less, and more preferably 20 μm or less. A thickness below a certain level makes it easier to peel the second adhesive layer from the carrier substrate, improving reworkability, which is preferable.

[0160] In the transfer double-sided adhesive sheet of the present invention, the haze of the second adhesive layer (according to JIS K7136) is not particularly limited, but is preferably 10% or less, and more preferably 5% or less. When the haze is 10% or less, excellent transparency is obtained, and for example, when the transfer double-sided adhesive sheet is attached to a carrier substrate, the pattern attached to the carrier substrate (for example, a marker indicating the receiving position of an electronic component) can be visually confirmed, which is preferable. The haze can be measured, for example, by forming the second adhesive layer on a separator, leaving it to stand at normal conditions (23°C, 50%RH) for at least 24 hours, peeling off the separator, and attaching the sample to a glass slide (for example, one with a total light transmittance of 91.8% and a haze of 0.4%), and using a haze meter (manufactured by Murakami Color Technology Laboratory Co., Ltd., product name "HM-150").

[0161] In the double-sided adhesive sheet for transfer of the present invention, the total light transmittance of the second adhesive layer in the visible light wavelength range (according to JIS K7361-1) is not particularly limited, but is preferably 85% or more, and more preferably 88% or more. A total light transmittance of 85% or more provides excellent transparency, and is preferable because, for example, when the double-sided adhesive sheet for transfer is attached to a carrier substrate, the pattern attached to the carrier substrate (for example, a marker indicating the receiving position of an electronic component) can be visually confirmed. The total light transmittance can be measured, for example, by forming the second adhesive layer on a separator, leaving it to stand at normal conditions (23°C, 50%RH) for at least 24 hours, peeling off the separator, and attaching the sample to a glass slide (for example, one with a total light transmittance of 91.8% and haze of 0.4%), using a haze meter (manufactured by Murakami Color Technology Laboratory Co., Ltd., product name "HM-150").

[0162] The adhesive constituting the second adhesive layer described above is not particularly limited, but examples include silicone-based adhesives, urethane-based adhesives, acrylic-based adhesives, rubber-based adhesives, polyester-based adhesives, polyamide-based adhesives, epoxy-based adhesives, vinyl alkyl ether-based adhesives, and fluorine-based adhesives, which are used in the first adhesive layer described above. Among these, silicone-based adhesives, urethane-based adhesives, and acrylic-based adhesives are preferred from the viewpoint of being able to be peeled off from the carrier substrate without contamination such as adhesive residue, and improving reworkability, with urethane-based adhesives and acrylic-based adhesives being more preferred, and acrylic-based adhesives being even more preferred.

[0163] The second adhesive layer in the double-sided adhesive sheet for transfer of the present invention may be an adhesive layer that can be intentionally reduced by external action during the process of using the double-sided adhesive sheet for transfer (adhesive strength reduction type adhesive layer), or it may be an adhesive layer that does not have its adhesive strength reduced by external action during the process of using the double-sided adhesive sheet for transfer (adhesive strength non-reduction type adhesive layer), and can be appropriately selected depending on the method and conditions for transferring electronic components using the double-sided adhesive sheet for transfer of the present invention.

[0164] When the second adhesive layer is a type of adhesive layer whose adhesive strength can be reduced, it becomes possible to differentiate between a state in which the second adhesive layer exhibits relatively high adhesive strength and a state in which it exhibits relatively low adhesive strength during the manufacturing and use processes of the double-sided adhesive sheet for transfer according to the present invention. For example, in the process of the first adhesive layer receiving electronic components during the use of the double-sided adhesive sheet for transfer according to the present invention, it is possible to suppress and prevent the lifting of the double-sided adhesive sheet for transfer from the carrier substrate by utilizing the state in which the second adhesive layer exhibits relatively high adhesive strength. On the other hand, in the subsequent process of peeling the double-sided adhesive sheet for transfer according to the present invention from the carrier substrate, the reworkability can be improved by reducing the adhesive strength of the second adhesive layer.

[0165] Examples of adhesives that form such a tack-reducing adhesive layer include radiation-curable adhesives and heat-foaming adhesives. One type of adhesive may be used to form the tack-reducing adhesive layer, or two or more types of adhesives may be used.

[0166] As the above-mentioned radiation-curable adhesive, for example, an adhesive that hardens upon irradiation with electron beams, ultraviolet rays, alpha rays, beta rays, gamma rays, or X-rays can be used, and an adhesive that hardens upon irradiation with ultraviolet rays (ultraviolet-curable adhesive) can be used in particular preference.

[0167] Examples of the above-mentioned radiation-curable adhesives include additive-type radiation-curable adhesives containing a base polymer such as an acrylic polymer and radiation-polymerizable monomer components or oligomer components having radiation-polymerizable functional groups such as carbon-carbon double bonds.

[0168] As the base polymer, an acrylic polymer similar to that used in the first adhesive layer can be used. To appropriately express the basic properties such as tackiness due to hydrocarbon group-containing (meth)acrylic acid ester in the second adhesive layer, and to easily control tackiness and peelability, the proportion of hydrocarbon group-containing (meth)acrylic acid ester in the total monomer components for forming the acrylic polymer is preferably 40% by mass or more, and more preferably 60% by mass or more.

[0169] The above-mentioned acrylic polymer may contain a hydroxyl group-containing monomer. When the acrylic polymer in the second adhesive layer contains a hydroxyl group-containing monomer, an appropriate cohesive force is easily obtained in the second adhesive layer. From the viewpoint of achieving appropriate adhesion and cohesive force in the second adhesive layer, the proportion of the hydroxyl group-containing monomer in the above-mentioned acrylic polymer is, for example, 0.1 to 30% by mass, and preferably 0.5 to 20% by mass.

[0170] The above-mentioned acrylic polymer may contain a carboxyl group-containing monomer. When the acrylic polymer in the second adhesive layer contains a carboxyl group-containing monomer, it is easier to obtain adequate adhesive reliability in the second adhesive layer. From the viewpoint of achieving adequate adhesive reliability in the second adhesive layer, the proportion of the carboxyl group-containing monomer in the above-mentioned acrylic polymer is, for example, 0.1 to 30% by mass, and preferably 0.5 to 20% by mass.

[0171] The above-mentioned acrylic polymer may also contain a vinyl ester monomer. When the acrylic polymer in the second adhesive layer contains a vinyl ester monomer, an appropriate cohesive force is easily obtained in the second adhesive layer. From the viewpoint of achieving an appropriate cohesive force in the second adhesive layer, the proportion of the vinyl ester monomer in the above-mentioned acrylic polymer is, for example, 0.1 to 60% by mass, and preferably 0.5 to 50% by mass.

[0172] The acrylic adhesive composition forming the second adhesive layer may contain a crosslinking agent. For example, the acrylic polymer can be crosslinked to further reduce the amount of low molecular weight substances in the second adhesive layer. Furthermore, the mass-average molecular weight of the acrylic polymer can be increased to control low tackiness and release properties. Examples of the crosslinking agent include polyisocyanate compounds, epoxy compounds, polyol compounds (such as polyphenol compounds), aziridine compounds, and melamine compounds. When using an isocyanate-based crosslinking agent and / or epoxy-based crosslinking agent, the amount used is preferably about 10 parts by mass or less, and more preferably 0.1 to 10 parts by mass, per 100 parts by mass of the acrylic polymer.

[0173] The acrylic adhesive composition forming the second adhesive layer may contain a crosslinking accelerator. The type of crosslinking accelerator can be appropriately selected depending on the type of crosslinking agent used. In this specification, a crosslinking accelerator refers to a catalyst that increases the rate of the crosslinking reaction by the crosslinking agent. Examples of such crosslinking accelerators include tin (Sn)-containing compounds such as dioctyl tin dilaurate, dibutyl tin dilaurate, dibutyl tin diacetate, dibutyl tin diacetylacetonate, tetra-n-butyl tin, and trimethyl tin hydroxide; amines such as N,N,N',N'-tetramethylhexanediamine and triethylamine; and N-containing compounds such as imidazoles. Among these, Sn-containing compounds are preferred. The use of these crosslinking accelerators is particularly effective when a hydroxyl group-containing monomer is used as the sub-monomer and an isocyanate-based crosslinking agent is used as the crosslinking agent. The amount of crosslinking accelerator contained in the above adhesive composition can be, for example, about 0.001 to 0.5 parts by mass (preferably about 0.001 to 0.1 parts by mass) per 100 parts by mass of the acrylic polymer.

[0174] Examples of the above radiation-polymerizable monomer components include urethane (meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and 1,4-butanediol di(meth)acrylate. Examples of the above radiation-polymerizable oligomer components include various oligomers such as urethane-based, polyether-based, polyester-based, polycarbonate-based, and polybutadiene-based oligomers, with a molecular weight of approximately 100 to 30,000 being preferred. The content of the above radiation-curable monomer components and oligomer components in the radiation-curable adhesive forming the second adhesive layer is, for example, 5 to 500 parts by mass, preferably 40 to 150 parts by mass, per 100 parts by mass of the base polymer. Furthermore, as an additive-type radiation-curable adhesive, for example, the one disclosed in Japanese Patent Publication No. 60-196956 may be used.

[0175] The above-mentioned radiation-curable adhesives also include intrinsically charged radiation-curable adhesives containing a base polymer having radiation-polymerizable functional groups such as carbon-carbon double bonds in the polymer side chains, polymer main chain, or polymer main chain ends. Using such intrinsically charged radiation-curable adhesives tends to suppress unintended changes in adhesive properties over time caused by the movement of low molecular weight components within the formed second adhesive layer.

[0176] As the base polymer contained in the above-mentioned intrinsically charged radiation-curable adhesive, an acrylic polymer is preferred. As a method for introducing a radiation-polymerizable carbon-carbon double bond into an acrylic polymer, for example, an acrylic polymer is obtained by polymerizing (copolymerizing) a raw material monomer containing a monomer component having a first functional group, and then a compound having a second functional group that can react with the first functional group and a radiation-polymerizable carbon-carbon double bond is subjected to a condensation or addition reaction with the acrylic polymer while maintaining the radiation polymerizability of the carbon-carbon double bond.

[0177] Examples of combinations of the first functional group and the second functional group include carboxyl group and epoxy group, epoxy group and carboxyl group, carboxyl group and aziridyl group, aziridyl group and carboxyl group, hydroxyl group and isocyanate group, and isocyanate group and hydroxyl group. Among these, from the viewpoint of ease of reaction tracking, combinations of hydroxyl group and isocyanate group, and combinations of isocyanate group and hydroxyl group are preferred. In particular, producing polymers having highly reactive isocyanate groups is technically difficult, while from the viewpoint of ease of production and acquisition of acrylic polymers having hydroxyl groups, a combination in which the first functional group is a hydroxyl group and the second functional group is an isocyanate group is preferred. Examples of compounds having an isocyanate group and a radioactively polymerizable carbon-carbon double bond, i.e., radioactively polymerizable unsaturated functional group-containing isocyanate compounds, include methacryloyl isocyanate, 2-methacryloyloxyethyl isocyanate, and m-isopropenyl-α,α-dimethylbenzyl isocyanate. Furthermore, examples of acrylic polymers having hydroxyl groups include those containing the above-mentioned hydroxyl group-containing monomers, as well as constituent units derived from ether compounds such as 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, and diethylene glycol monovinyl ether.

[0178] The above radiation-curable adhesive preferably contains a photopolymerization initiator. Examples of the above photopolymerization initiator include α-ketol compounds, acetophenone compounds, benzoin ether compounds, ketal compounds, aromatic sulfonyl chloride compounds, photoactive oxime compounds, benzophenone compounds, thioxanthone compounds, camphorquinone, halogenated ketones, acylphosphinoxides, and acylphosphonates. Examples of the above α-ketol compounds include 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone, α-hydroxy-α,α'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, and 1-hydroxycyclohexylphenyl ketone. Examples of the above acetophenone compounds include methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, and 2-methyl-1-[4-(methylthio)-phenyl]-2-morpholinopropane-1. Examples of the above benzoin ether compounds include benzoin ethyl ether, benzoin isopropyl ether, and anisoin methyl ether. Examples of the above ketal compounds include benzyldimethyl ketal. Examples of the above aromatic sulfonyl chloride compounds include 2-naphthalenesulfonyl chloride. Examples of the above photoactive oxime compounds include 1-phenyl-1,2-propanedione-2-(O-ethoxycarbonyl)oxime. Examples of the above benzophenone compounds include benzophenone, benzoylbenzoic acid, and 3,3'-dimethyl-4-methoxybenzophenone. Examples of the thioxanthone compounds mentioned above include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, and 2,4-diisopropylthioxanthone. The content of the photopolymerization initiator in the radiation-curable adhesive is, for example, 0.05 to 20 parts by mass per 100 parts by mass of the base polymer.

[0179] The above-mentioned heat-foaming adhesive is an adhesive containing components (foaming agents, thermally expandable microspheres, etc.) that foam or expand upon heating. Examples of the foaming agents include various inorganic and organic foaming agents. Examples of the inorganic foaming agents include ammonium carbonate, ammonium bicarbonate, sodium bicarbonate, ammonium nitrite, sodium borohydride, and azides. Examples of the above-mentioned organic blowing agents include salt fluoride alkanes such as trichloromonofluoromethane and dichloromonofluoromethane; azo compounds such as azobisisobutyronitrile, azodicarbonamide, and barium azodicarboxylate; hydrazine compounds such as p-toluenesulfonyl hydrazide, diphenylsulfon-3,3'-disulfonyl hydrazide, 4,4'-oxybis(benzenesulfonyl hydrazide), and allylbis(sulfonyl hydrazide); semicarbazide compounds such as p-toluenesulfonyl semicarbazide and 4,4'-oxybis(benzenesulfonyl semicarbazide); triazole compounds such as 5-morpholyl-1,2,3,4-thiatriazole; and N-nitroso compounds such as N,N'-dinitrosopentamethylenetetramine and N,N'-dimethyl-N,N'-dinitrosotelephthalamide. Examples of the above-mentioned thermally expandable microspheres include microspheres in which a substance that readily gasifies and expands upon heating is enclosed within the shell. Examples of substances that readily gasifies and expand upon heating include isobutane, propane, and pentane. Thermally expandable microspheres can be produced by enclosing a substance that readily gasifies and expands upon heating within a shell-forming material using methods such as coacervation or interfacial polymerization. As the shell-forming material, substances that exhibit thermal fusion or substances that can rupture due to the thermal expansion of the enclosed material can be used. Examples of such substances include vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, and polysulfone.

[0180] Examples of the non-reducing adhesive layer mentioned above include a pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer includes an adhesive layer formed from the radiation-curable adhesive described above, which is pre-cured by radiation irradiation while maintaining a certain level of adhesion. The adhesive forming the non-reducing adhesive layer may be one type of adhesive or two or more types of adhesives. Furthermore, the entire second adhesive layer may be a non-reducing adhesive layer, or only a portion of it may be a non-reducing adhesive layer. For example, if the second adhesive layer has a single-layer structure, the entire second adhesive layer may be a non-reducing adhesive layer, or a specific portion of the second adhesive layer may be a non-reducing adhesive layer while other portions are adhesive layers with reduced adhesion. Also, if the second adhesive layer has a laminated structure, all adhesive layers in the laminated structure may be non-reducing adhesive layers, or some adhesive layers in the laminated structure may be non-reducing adhesive layers.

[0181] An adhesive layer formed from a radiation-curable adhesive (a radiation-curable adhesive layer that has not been irradiated) and then cured in advance by radiation (a radiation-irradiated radiation-curable adhesive layer) exhibits tackiness due to the polymer components it contains, even if its tackiness is reduced by radiation, and is capable of exhibiting the minimum tackiness required for the double-sided adhesive sheet for transfer of the present invention. When using a radiation-irradiated radiation-curable adhesive layer, the entire second adhesive layer may be a radiation-irradiated radiation-curable adhesive layer in the direction of surface expansion of the second adhesive layer, or a part of the second adhesive layer may be a radiation-irradiated radiation-curable adhesive layer and the other part may be an unirradiated radiation-curable adhesive layer. In this specification, "radiation-curable adhesive layer" refers to an adhesive layer formed from a radiation-curable adhesive, and includes both an unirradiated radiation-curable radiation-curable adhesive layer that has radiation-curability and a radiation-cured radiation-curable adhesive layer that has been cured by radiation.

[0182] As the adhesive forming the pressure-sensitive adhesive layer described above, known or conventional pressure-sensitive adhesives can be used, and acrylic adhesives with an acrylic polymer as the base polymer are preferably used. When the second adhesive layer contains an acrylic polymer as a pressure-sensitive adhesive, it is preferable that the acrylic polymer is a polymer in which the constituent units derived from (meth)acrylic acid ester are the most abundant by mass. As the acrylic polymer described above, for example, an acrylic polymer that can be included in the additive-type radiation-curable adhesive described above can be used.

[0183] (base material) In the double-sided adhesive sheet for transfer according to the present invention, the substrate is an element that functions as a support in the first adhesive layer and the second adhesive layer. Examples of substrates include plastic substrates (particularly plastic films). The substrate may be a single layer or a laminate of the same or different types of substrates.

[0184] Examples of resins constituting the above-mentioned plastic substrates include polyolefin resins such as low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, ultra-low-density polyethylene, random copolymer polypropylene, block copolymer polypropylene, homopolypropylene, polybutene, polymethylpentene, ethylene-vinyl acetate copolymer (EVA), ionomer, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid ester (random, alternating) copolymer, ethylene-butene copolymer, and ethylene-hexene copolymer; polyurethane; polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate, and polybutylene terephthalate (PBT); polycarbonate; polyimide; polyether ether ketone; polyetherimide; polyamides such as aramid and fully aromatic polyamide; polyphenyl sulfide; fluororesin; polyvinyl chloride; polyvinylidene chloride; cellulose resin; and silicone resin. When the double-sided adhesive sheet for transfer of the present invention is used to transfer and mount electronic components onto a mounting substrate by thermocompression (for example, at 150°C), the substrate preferably contains a heat-resistant resin such as polyimide (PI), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyamide (PA), or polyether ether ketone (PEEK) as its main component, and more preferably polyimide as its main component. The main component of the substrate is defined as the component that accounts for the largest mass proportion among the constituent components. Only one type of resin may be used, or two or more types may be used. When the second adhesive layer is a radiation-curable adhesive layer as described above, the substrate preferably has radiation transparency.

[0185] When the base material is a plastic film, the plastic film may be unoriented or oriented in at least one direction (uniaxial direction, biaxial direction, etc.), but unoriented is preferred because it is less likely to exhibit thermal shrinkage.

[0186] The surface of the substrate facing the first adhesive layer and / or the second adhesive layer may be subjected to surface treatments such as physical treatments like corona discharge treatment, plasma treatment, sandblasting, ozone exposure treatment, flame exposure treatment, high-voltage electric shock exposure treatment, and ionization radiation treatment; chemical treatments like chromic acid treatment; coating agents (primers); and easy-adhesion treatments using silicone primers, in order to improve adhesion and retention with the adhesive layer. In addition, to impart antistatic properties, a conductive vapor-deposited layer containing metals, alloys, or oxides thereof may be provided on the substrate surface, or a conductive polymer such as PEDOT-PSS may be coated. It is preferable that the surface treatment to improve adhesion is applied to the entire surface of the substrate facing the adhesive layer.

[0187] From the viewpoint of ensuring sufficient strength for the substrate to function as a support in the double-sided adhesive sheet for transfer of the present invention, the thickness of the substrate is preferably 5 μm or more, more preferably 10 μm or more, even more preferably 15 μm or more, and particularly preferably 20 μm or more. Furthermore, from the viewpoint of achieving appropriate flexibility in the double-sided adhesive sheet for transfer of the present invention, the thickness of the substrate is preferably 200 μm or less, more preferably 180 μm or less, and even more preferably 150 μm or less.

[0188] In the double-sided adhesive sheet for transfer of the present invention, the haze of the substrate (according to JIS K7136) is not particularly limited, but is preferably 10% or less, and more preferably 5.0% or less. When the haze is 10% or less, excellent transparency is obtained, and for example, when the double-sided adhesive sheet for transfer is attached to a carrier substrate, the pattern attached to the carrier substrate (for example, a marker indicating the receiving position of an electronic component) can be visually confirmed, which is preferable. The above haze can be measured using a haze meter (manufactured by Murakami Color Technology Laboratory Co., Ltd., product name "HM-150").

[0189] In the double-sided adhesive sheet for transfer of the present invention, the total light transmittance of the substrate in the visible light wavelength range (according to JIS K7361-1) is not particularly limited, but is preferably 85% or more, and more preferably 88% or more. A total light transmittance of 85% or more provides excellent transparency, and is preferable because, for example, when the double-sided adhesive sheet for transfer is attached to a carrier substrate, the pattern attached to the carrier substrate (for example, a marker indicating the receiving position of an electronic component) can be visually confirmed. The above total light transmittance can be measured using a haze meter (manufactured by Murakami Color Technology Laboratory Co., Ltd., product name "HM-150").

[0190] (Separator) The adhesive layer surface (adhesive surface of the first adhesive layer and / or second adhesive layer) of the transfer double-sided adhesive sheet of the present invention may be protected by a separator until use. The separator is used as a protective material for the adhesive layer and is peeled off when the adhesive sheet is attached to the substrate. Figure 2 is a schematic cross-sectional view showing one embodiment of the transfer double-sided adhesive sheet of the present invention, where 1 is the transfer double-sided adhesive sheet, 10 is the substrate, 11 is the first adhesive layer, 12 is the second adhesive layer, and 110 and 120 are separators. Note that the separator is not necessarily provided.

[0191] As the separator mentioned above, conventional release paper can be used. Specifically, for example, in addition to a substrate having a release treatment layer with a release treatment agent on at least one surface, low-adhesion substrates made of fluorine-based polymers (e.g., polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, chlorofluoroethylene-vinylidene fluoride copolymer, etc.) or low-adhesion substrates made of non-polar polymers (e.g., polyethylene, polypropylene, and other olefin resins) can be used.

[0192] As the above-mentioned separator, for example, a separator in which a release treatment layer is formed on at least one surface of the separator substrate can be suitably used. Examples of such separator substrates include plastic substrate films (synthetic resin films) such as polyester film (polyethylene terephthalate film, etc.), olefin resin film (polyethylene film, polypropylene film, etc.), polyvinyl chloride film, polyimide film, polyamide film (nylon film), and rayon film, as well as paper (high-quality paper, Japanese paper, kraft paper, glassine paper, synthetic paper, topcoat paper, etc.), and composites of these made by laminating or co-extruding (composites of 2-3 layers).

[0193] The release agent constituting the above-mentioned release layer is not particularly limited, but for example, silicone-based release agents, fluorine-based release agents, long-chain alkyl-based release agents, etc., can be used. The release agent can be used alone or in combination of two or more types. Furthermore, since the first adhesive layer is composed of a low-tack adhesive layer, it is possible to use a substrate that has not been treated with a release agent as a separator.

[0194] To prevent adverse effects on electronic components, the above-mentioned separator may have an antistatic layer formed on at least one surface of the separator substrate. The antistatic layer may be formed on one surface of the separator (the peeled surface or the untreated surface), or on both surfaces of the separator (the peeled surface and the untreated surface).

[0195] Examples of antistatic agents contained in the antistatic resin forming the antistatic layer include cationic antistatic agents having cationic functional groups such as quaternary ammonium salts, pyridinium salts, and primary, secondary, and tertiary amino groups; anionic antistatic agents having anionic functional groups such as sulfonates, sulfate esters, phosphonates, and phosphate esters; amphoteric antistatic agents such as alkyl betaines and their derivatives, imidazolines and their derivatives, and alanine and its derivatives; nonionic antistatic agents such as amino alcohols and their derivatives, glycerin and its derivatives, and polyethylene glycol and its derivatives; and ion-conductive polymers obtained by polymerizing or copolymerizing monomers having the above-mentioned cationic, anionic, and amphoteric ion-conductive groups. These compounds may be used individually or in combination of two or more.

[0196] The thickness of the separator is not particularly limited and can be appropriately selected from the range of 5 to 100 μm.

[0197] The method for manufacturing the double-sided adhesive sheet for transfer according to the present invention varies depending on the composition of the adhesive composition and other factors, and is not particularly limited; known forming methods can be used, but examples include the following methods (1) to (4). (1) A method for manufacturing an adhesive sheet by applying (coating) the above adhesive composition onto a substrate to form a composition layer, and curing the composition layer (for example, by heat curing or curing by irradiation with active energy rays such as ultraviolet light) to form an adhesive layer. (2) A method for producing an adhesive sheet by applying the above adhesive composition onto a separator to form a composition layer, curing the composition layer (for example, by heat curing or curing by irradiation with active energy rays such as ultraviolet light) to form an adhesive layer, and then transferring the adhesive layer onto a substrate. (3) A method for producing an adhesive sheet by applying the above adhesive composition onto a substrate, drying it to form an adhesive layer. (4) A method for producing an adhesive sheet by applying the above adhesive composition onto a separator, drying it to form an adhesive layer, and then transferring the adhesive layer onto a substrate.

[0198] Of the curing methods described in (1) to (4) above, a heat curing method is preferred because it offers excellent productivity and allows for the formation of a homogeneous and smooth-surfaced adhesive layer.

[0199] The method for applying (coating) the above adhesive composition onto a predetermined surface can be any known coating method, and is not particularly limited. Examples include roll coating, kiss roll coating, gravure coating, reverse coating, roll brushing, spray coating, dip roll coating, bar coating, knife coating, air knife coating, curtain coating, lip coating, and extrusion coating methods using a die coater.

[0200] The thickness (total thickness) of the double-sided adhesive sheet for transfer according to the present invention is not particularly limited, but is preferably 10 μm or more, and more preferably 15 μm or more. A thickness above a certain level is preferable because it makes it easier for the first adhesive layer to accurately receive electronic components. Furthermore, the upper limit of the thickness (total thickness) of the double-sided adhesive sheet for transfer according to the present invention is not particularly limited, but is preferably 500 μm or less, and more preferably 300 μm or less. A thickness below a certain level is preferable because it makes it easier to accurately transfer electronic components to the mounting substrate. Note that the thickness of the double-sided adhesive sheet for transfer according to the present invention does not include the thickness of the separator.

[0201] The haze of the double-sided adhesive sheet for transfer according to the present invention (according to JIS K7136) is not particularly limited, but is preferably 10% or less, and more preferably 5.0% or less. A haze of 10% or less is preferable because it provides excellent transparency, allowing, for example, when the double-sided adhesive sheet for transfer is attached to a carrier substrate, the pattern attached to the carrier substrate (e.g., a marker indicating the receiving position of an electronic component) to be visually inspected. The haze can be measured, for example, by leaving the double-sided adhesive sheet for transfer at normal conditions (23°C, 50%RH) for at least 24 hours, peeling off the separator if present, and attaching the sample to a glass slide (e.g., one with a total light transmittance of 91.8% and a haze of 0.4%), using a haze meter (manufactured by Murakami Color Technology Laboratory Co., Ltd., product name "HM-150").

[0202] The total light transmittance (according to JIS K7361-1) in the visible light wavelength range of the double-sided adhesive sheet for transfer of the present invention is not particularly limited, but is preferably 85% or higher, and more preferably 88% or higher. A total light transmittance of 85% or higher is preferable because it provides excellent transparency, allowing, for example, when the double-sided adhesive sheet for transfer is attached to a carrier substrate, the pattern attached to the carrier substrate (for example, a marker indicating the receiving position of an electronic component) to be visually inspected. The total light transmittance can be measured, for example, by leaving the double-sided adhesive sheet for transfer at normal conditions (23°C, 50%RH) for at least 24 hours, peeling off the separator if present, and attaching the sample to a glass slide (for example, one with a total light transmittance of 91.8% and haze of 0.4%), using a haze meter (manufactured by Murakami Color Technology Laboratory Co., Ltd., product name "HM-150").

[0203] The double-sided adhesive sheet for transfer of the present invention is suitably used in methods for mounting electronic components onto a mounting substrate. The method for mounting electronic components onto a mounting substrate using the double-sided adhesive sheet for transfer of the present invention preferably includes the following steps. The first step involves the first adhesive layer of the double-sided adhesive sheet for transfer of the present invention receiving the diced electronic component. The second step involves transferring the electronic components received by the first adhesive layer to the mounting substrate.

[0204] Figure 3 is a schematic cross-sectional view showing one embodiment of the first step in a method for mounting electronic components onto a mounting substrate using the transfer double-sided adhesive sheet of the present invention.

[0205] In Figure 3(a), the transfer double-sided adhesive sheet 1 is attached to the carrier substrate 22 using the adhesive surface of the second adhesive layer 12. The surface of the carrier substrate 22 that is attached to the second adhesive layer 12 may have a marking pattern for arranging electronic components. Because the transfer double-sided adhesive sheet 1 is highly transparent, the marking pattern on the carrier substrate 22 can be visually confirmed.

[0206] On the upper part of the adhesive surface of the first adhesive layer 11 of the transfer double-sided adhesive sheet 1, a plurality of electronic components 21, which have been separated by dicing, are attached to the dicing tape 20 and are positioned opposite the adhesive surface of the first adhesive layer 11, spaced apart from each other.

[0207] In Figure 3(b), the electronic component 21 is pushed by the pin member 23 from the side of the dicing tape 20 to which the electronic component 21 is not attached, bringing the electronic component 21 close to the adhesive surface of the first adhesive layer 11, which then receives it. The receiving may be done by making contact with the first adhesive layer 11 or without contact. If receiving without contact, the electronic component 21 is pushed until it peels off the dicing tape 20 and falls onto the adhesive surface of the electronic component 21. When receiving with contact, the adhesive surface of the first adhesive layer 11 has low tackiness, so the stress on the electronic component 21 when it is received is weak, thus suppressing damage to the electronic component 21. When receiving without contact, the adhesive surface of the first adhesive layer 11 has low tackiness, so the fallen electronic component 21 can be caught with good positional accuracy. Alternatively, instead of using the pin member 23, the electronic component 21 may be peeled off the dicing tape 20 by irradiating it with radiation such as ultraviolet light or laser light.

[0208] The electronic components 21 may be received onto the first adhesive layer 11 individually or in batches. Figure 3(c) is a schematic cross-sectional view showing the configuration in which all the electronic components 21 of the dicing tape 20 have been received onto the adhesive surface of the first adhesive layer 11 of the transfer double-sided adhesive sheet 1.

[0209] Figure 4 is a schematic cross-sectional view showing the second step in the method for mounting electronic components onto a mounting substrate using the transfer double-sided adhesive sheet of the present invention.

[0210] As shown in Figure 4(a), the electronic components 21 arranged on the adhesive surface of the first adhesive layer 11 of the transfer double-sided adhesive sheet 1 are placed opposite and spaced apart from the circuit surface 31 (circuit pattern not shown) of the mounting substrate 30. Next, as shown in Figure 4(b), the circuit surface 31 of the mounting substrate 30 and the electronic components 21 arranged on the adhesive surface of the first adhesive layer 11 of the transfer double-sided adhesive sheet 1 are brought close together so that the electronic components 21 and the circuit surface 31 of the mounting substrate 30 come into contact.

[0211] The transfer of the electronic component 21 to the circuit surface 31 of the mounting substrate 30 may be performed by thermocompression bonding (for example, 150°C for 1 minute). Since the base material 10, the first adhesive layer 11, and / or the second adhesive layer 12 constituting the transfer double-sided adhesive sheet 1 have excellent heat resistance, they do not expand or contract or change in adhesive strength during thermocompression bonding, so the electronic component 21 can be transferred to the circuit surface 31 of the mounting substrate 30 with high accuracy.

[0212] Next, as shown in Figure 4(c), by separating the transfer double-sided adhesive sheet 1 and the mounting substrate 30, the electronic component 21 is peeled off from the first adhesive layer 11 and transferred to the circuit surface 31 of the mounting substrate 30. Since the first adhesive layer 11 is composed of a low-tack adhesive layer, the electronic component 21 peels off easily and can be efficiently mounted on the mounting substrate 30 without damage.

[0213] After the electronic component 21 is mounted on the mounting substrate 30, the double-sided adhesive sheet 1 for transfer shown in Figure 4(c) may be peeled off from the carrier substrate 22 (not shown). Since the second adhesive layer 12 is composed of a release adhesive layer, it can be peeled off without leaving any adhesive residue and has excellent reworkability, so the carrier substrate 22 can be easily reused.

[0214] The electronic components to be mounted on the substrate are not particularly limited, but they can be suitably used for fine, thin semiconductor chips and LED chips. [Examples]

[0215] The present invention will be described in more detail below with reference to examples, but the present invention is not limited in any way by these examples.

[0216] [Manufacturing Example 1]: Manufacturing of acrylic copolymer (1) In a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas inlet tube, and condenser, 100 parts by weight of 2-ethylhexyl acrylate (2EHA) (manufactured by Nippon Shokubai Co., Ltd.), 4 parts by weight of 2-hydroxyethyl acrylate (HEA) (manufactured by Toagosei Co., Ltd.), 0.02 parts by weight of 2,2'-azobisisobutyronitrile (manufactured by Wako Pure Chemical Industries, Ltd.) as a polymerization initiator, and 180 parts by weight of ethyl acetate were charged. Nitrogen gas was introduced while gently stirring, and the polymerization reaction was carried out for 6 hours while maintaining the liquid temperature in the flask at around 65°C to prepare a solution (solid content: 35% by weight) of an acrylic copolymer (1) with a weight-average molecular weight of 560,000.

[0217] [Manufacturing Example 2]: Manufacturing of acrylic copolymer (2) In a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas inlet tube, and condenser, 95 parts by weight of butyl acrylate (manufactured by Nippon Shokubai Co., Ltd.), 5 parts by weight of acrylic acid (manufactured by Toagosei Co., Ltd.), 0.2 parts by weight of 2,2'-azobisisobutyronitrile (manufactured by Wako Pure Chemical Industries, Ltd.) as a polymerization initiator, and 156 parts by weight of ethyl acetate were charged. Nitrogen gas was introduced while gently stirring, and the polymerization reaction was carried out for 10 hours while maintaining the liquid temperature in the flask at around 63°C to prepare a solution (solid content: 40% by weight) of an acrylic copolymer (2) with a weight-average molecular weight of 700,000.

[0218] [Manufacturing Example 3]: Manufacturing of acrylic copolymer (3) In a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas inlet tube, and condenser, 2.8 parts by weight of 80% acrylic acid (AA) (manufactured by Osaka Organic Chemical Industry Co., Ltd.), 44 parts by weight of 2-ethylhexyl acrylate (2EHA) (manufactured by Nippon Shokubai Co., Ltd.), 35.2 parts by weight of vinyl acetate (manufactured by Denka Co., Ltd.), and 20 parts by weight of toluene were charged and nitrogen gas was introduced while gently stirring, and the mixture was stirred for 1 hour. Then, 0.2 parts by weight of Niper BW (manufactured by NOF Corporation), diluted with 96 parts by weight of toluene, was added dropwise as a polymerization initiator, and the temperature of the solution in the flask was maintained at around 40°C. The temperature of the solution in the flask was then raised to 60°C and the polymerization reaction was carried out for 8 hours, and then the temperature was raised to 95°C and stirred for 4 hours to prepare a solution (solid content: 35% by weight) of an acrylic copolymer (3) with a weight-average molecular weight of 560,000.

[0219] [Manufacturing Example 4]: Manufacturing of urethane-based adhesive composition (2) The polyols used are: 85 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three OH groups; 13 parts by weight of Sannix GP-3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn=3000), a polyol having three OH groups; 2 parts by weight of Sannix GP-1000 (manufactured by Sanyo Chemical Industries, Ltd., Mn=1000), a polyol having three OH groups; 18 parts by weight of Coronate HX (manufactured by Nippon Polyurethane Industries Co., Ltd.), a polyfunctional alicyclic isocyanate compound; 0.1 parts by weight of catalyst (manufactured by Nippon Chemical Industrial Co., Ltd., trade name: Narsem Ferric), 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as a degradation inhibitor; and cetyl 2-ethylhexanoate (manufactured by Nisshin Oillio Group Co., Ltd.) as a fatty acid ester. A urethane-based adhesive composition (2) was prepared by mixing and stirring 5 parts by weight of (product name: Saracos 816T, Mn=368) manufactured by a certain company, and 0.2 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based surfactant, with ethyl acetate as a diluent.

[0220] [Example 1] (Preparation of double-sided adhesive sheets for transfer) 100 parts by weight of silicone adhesive 1 (addition reaction type silicone adhesive, trade name "X-40-3306", manufactured by Shin-Etsu Chemical Co., Ltd.), 1.4 parts by weight of platinum catalyst 1 (trade name "CAT-PL-50T", manufactured by Shin-Etsu Chemical Co., Ltd.), and 5 parts by weight of silicone release agent 1 (addition reaction type silicone release agent mainly composed of dimethylpolysiloxane, trade name "KS-776A", manufactured by Shin-Etsu Chemical Co., Ltd.) were added, diluted with toluene to a total solid content of 25% by weight, and mixed with a disperser to prepare a silicone adhesive composition (silicone adhesive composition 1). A silicone-based adhesive composition 1 was applied to the silicone-primer-treated side of a base film (1) (a polyester film with one side treated with a silicone primer, 75 μm thick, product name "Diafoil MRF#75", manufactured by Mitsubishi Plastics, Inc.) so that the adhesive thickness after drying was 10 μm. The film was then cured and dried at a drying temperature of 120°C for a drying time of 5 minutes. In this way, a film having a silicone-based adhesive layer (1) on the silicone-primer-treated layer of the base film (1) was obtained. Furthermore, a separator (1) (untreated polyethylene terephthalate film, 25 μm thick, trade name "Lumirror S10#25", manufactured by Toray Industries, Inc.) was laminated onto the adhesive surface of the silicone adhesive film to protect the silicone adhesive layer, thereby obtaining a laminate (1) having a laminated structure of [separator (1) layer] / [silicone adhesive (1) layer] / [base film (1) layer]. Next, to the solution of the acrylic copolymer (1) obtained in Production Example 1, 4.0 parts by weight of Coronate HX (manufactured by Tosoh Corporation) as a crosslinking agent and 0.02 parts by weight of Envirizer OL-1 (manufactured by Tokyo Fine Chemical Co., Ltd.) as a crosslinking catalyst were added per 100 parts by weight of solids. The solution was diluted with toluene so that the total solids content was 25% by weight, and the acrylic adhesive composition was stirred with a disperser. This acrylic adhesive composition was applied to the release-treated layer side of separator (2) (release-treated polyethylene terephthalate film, thickness 38 μm, trade name "MRF#38", manufactured by Mitsubishi Chemical Corporation) using a fountain roll so that the thickness after drying was 20 μm. The film was then cured and dried under conditions of a drying temperature of 130°C and a drying time of 30 seconds. In this way, an acrylic adhesive layer (1) was formed on separator (2). Next, the base film (1) side (the side not treated with silicone primer) of the laminate (1) obtained above was bonded to the surface of the acrylic adhesive layer (1) to obtain a double-sided adhesive sheet for transfer having a laminated structure of [separator (1) layer] / [silicone adhesive (1) layer (first adhesive layer)] / [base film (1) layer] / [acrylic adhesive (1) layer (second adhesive layer)] / [separator (2) layer].

[0221] [Example 2] Except for adding 6 parts by weight of TETRAD-C (manufactured by Mitsubishi Gas Chemical Co., Ltd.) as a crosslinking agent to 100 parts by weight of the solid content of the acrylic copolymer (2) obtained in Production Example 2, diluting it with ethyl acetate so that the total solid content was 25% by weight, stirring with a disperser, and coating the resulting acrylic adhesive composition onto the separator (2), a double-sided adhesive sheet for transfer having a laminated structure of [separator (1) layer] / [silicone adhesive (1) layer (first adhesive layer)] / [base film (1) layer] / [acrylic adhesive (2) layer (second adhesive layer)] / [separator (2) layer] was obtained in the same manner as in Example 1.

[0222] [Example 3] A double-sided adhesive sheet for transfer was obtained in the same manner as in Example 1, except that 4.0 parts by weight of Coronate L (manufactured by Tosoh Corporation) was added to 100 parts by weight of solids of the acrylic copolymer (1) solution obtained in Production Example 1, instead of Coronate HX as a crosslinking agent, based on solid content, to obtain a double-sided adhesive sheet for transfer having a laminated structure of [separator (1) layer] / [silicone adhesive (1) layer (first adhesive layer)] / [base film (1) layer] / [acrylic adhesive (3) layer (second adhesive layer)] / [separator (2) layer].

[0223] [Example 4] Except for adding 2.0 parts by weight of TETRAD-C (manufactured by Mitsubishi Gas Chemical Co., Ltd.) as a crosslinking agent to 100 parts by weight of the solids of the acrylic copolymer (3) obtained in Production Example 3, diluting with methyl ethyl ketone so that the total solids content is 25% by weight, stirring with a disperser, and coating the resulting acrylic adhesive composition onto the separator (2), a double-sided adhesive sheet for transfer having a laminated structure of [separator (1) layer] / [silicone adhesive (1) layer (first adhesive layer)] / [base film (1) layer] / [acrylic adhesive (4) layer (second adhesive layer)] / [separator (2) layer] was obtained in the same manner as in Example 1.

[0224] [Example 5] As a prepolymer-type urethane adhesive composition (1), a solution of Ciabein SH-109 (manufactured by Toyo Chem Co., Ltd.) was prepared by adding 4.0 parts by weight of Coronate HX (manufactured by Tosoh Corporation) as a crosslinking agent, 10 parts by weight of Saracos 913 (manufactured by Nisshin Oillio Co., Ltd.) as a light release agent, 1 part by weight of the fluorine-based surfactant Megafac F-571 (manufactured by DIC Corporation), and 0.5 parts by weight of Irgacure 1010 (manufactured by BASF Corporation) as a degradation inhibitor, to a solution of Ciabein SH-109 (manufactured by Toyo Chem Co., Ltd.) based on solid content, and diluting with ethyl acetate to a total solid content of 20% by weight, and stirring with a DIZUR, and the resulting prepolymer-type urethane adhesive solution was used as a base film (2) (untreated PET film, thickness 75 μm, product name "Lumirror S10 #75", manufactured by Toray Industries, Inc.). The film was coated to a thickness of 20 μm after drying, cured and dried at a drying temperature of 130°C for 30 seconds, and a separator (2) (a release-treated polyethylene terephthalate film, 38 μm thick, trade name "MRF#38", manufactured by Mitsubishi Chemical Corporation) was laminated onto the adhesive surface of the resulting urethane adhesive film to protect the urethane adhesive layer. In this manner, a double-sided adhesive sheet for transfer was obtained having a laminated structure of [separator (2) layer] / [urethane adhesive (1) layer (first adhesive layer)] / [base film (2) layer] / [acrylic adhesive (1) layer (second adhesive layer)] / [separator (2) layer].

[0225] [Comparative Example 1] Except for adding 0.01 parts by weight of TETRAD-C (manufactured by Mitsubishi Gas Chemical Co., Ltd.) as a crosslinking agent to 100 parts by weight of the solid content of the acrylic copolymer (2) obtained in Production Example 2, diluting it with ethyl acetate so that the total solid content was 25% by weight, stirring with a disperser, and coating the resulting acrylic adhesive composition onto the separator (2), a double-sided adhesive sheet for transfer having a laminated structure of [separator (1) layer] / [silicone adhesive (1) layer (first adhesive layer)] / [base film (1) layer] / [acrylic adhesive (5) layer (second adhesive layer)] / [separator (2) layer] was obtained in the same manner as in Example 1.

[0226] [Comparative Example 2] Except for using a thermosetting polyurethane resin film (manufactured by Toray Industries, Inc., a 100 μm thick polyurethane resin film (100% modulus = 32 MPa) protected by a 50 μm thick surface protective film) instead of the laminate (1), a double-sided transfer sheet having a laminated structure of [surface protective film layer] / [polyurethane resin film layer] / [acrylic adhesive (1) layer (second adhesive layer)] / [separator (2) layer] was obtained in the same manner as in Example 1.

[0227] [Comparative Example 3] As a substitute for silicone-based adhesive composition 1, the acrylic adhesive composition used in Example 1 was applied to a base film (2) (untreated PET film, 75 μm thick, trade name "Lumirror S10#75", manufactured by Toray Industries, Inc.) so that the thickness after drying was 20 μm. The film was cured and dried at a drying temperature of 130°C for 30 seconds. Separator (2) (released polyethylene terephthalate film, 38 μm thick, trade name "MRF#38", manufactured by Mitsubishi Chemical Corporation) was laminated onto the adhesive surface of the resulting acrylic adhesive film to protect the acrylic adhesive layer. In this manner, a double-sided adhesive sheet for transfer was obtained having a laminated structure of [separator (2) layer] / [acrylic adhesive (1) layer (first adhesive layer)] / [base film (2) layer] / [acrylic adhesive (1) layer (second adhesive layer)] / [separator (2) layer].

[0228] [Comparative Example 4] As a substitute for silicone-based adhesive composition 1, the acrylic adhesive composition used in Example 2 was applied to a base film (2) (untreated PET film, 75 μm thick, trade name "Lumirror S10#75", manufactured by Toray Industries, Inc.) so that the thickness after drying was 20 μm. The film was cured and dried at a drying temperature of 130°C for 30 seconds. Separator (2) (released polyethylene terephthalate film, 38 μm thick, trade name "MRF#38", manufactured by Mitsubishi Chemical Corporation) was laminated onto the adhesive surface of the resulting acrylic adhesive film to protect the acrylic adhesive layer. In this manner, a double-sided adhesive sheet for transfer was obtained having a laminated structure of [separator (2) layer] / [acrylic adhesive (2) layer (first adhesive layer)] / [base film (2) layer] / [acrylic adhesive (1) layer (second adhesive layer)] / [separator (2) layer].

[0229] [Comparative Example 5] As a substitute for silicone adhesive composition 1, the acrylic adhesive composition used in Example 3 was applied to a base film (2) (untreated PET film, 75 μm thick, trade name "Lumirror S10#75", manufactured by Toray Industries, Inc.) so that the thickness after drying was 20 μm. The film was cured and dried at a drying temperature of 130°C for 30 seconds. Separator (2) (released polyethylene terephthalate film, 38 μm thick, trade name "MRF#38", manufactured by Mitsubishi Chemical Corporation) was laminated onto the adhesive surface of the resulting acrylic adhesive film to protect the acrylic adhesive layer. Except for these steps, a double-sided transfer sheet having a laminated structure of [separator (2) layer] / [acrylic adhesive (3) layer (first adhesive layer)] / [base film (2) layer] / [acrylic adhesive (1) layer (second adhesive layer)] / [separator (2) layer] was obtained in the same manner as in Example 1.

[0230] [Comparative Example 6] As a substitute for silicone adhesive composition 1, the acrylic adhesive composition used in Example 4 was applied to a base film (2) (untreated PET film, 75 μm thick, trade name "Lumirror S10#75", manufactured by Toray Industries, Inc.) so that the thickness after drying was 20 μm. The film was cured and dried at a drying temperature of 130°C for 30 seconds. Separator (2) (released polyethylene terephthalate film, 38 μm thick, trade name "MRF#38", manufactured by Mitsubishi Chemical Corporation) was laminated onto the adhesive surface of the resulting acrylic adhesive film to protect the acrylic adhesive layer. Except for these steps, a double-sided transfer sheet having a laminated structure of [separator (2) layer] / [acrylic adhesive (4) layer (first adhesive layer)] / [base film (2) layer] / [acrylic adhesive (1) layer (second adhesive layer)] / [separator (2) layer] was obtained in the same manner as in Example 1.

[0231] [Comparative Example 7] In the same procedure as in Example 1, a double-sided adhesive sheet for transfer was obtained having a laminated structure of [separator (2) layer] / [urethane adhesive (2) layer (first adhesive layer)] / [base film (1) layer] / [acrylic adhesive (1) layer (second adhesive layer)] / [separator (2) layer]. The urethane adhesive composition (2) obtained in Production Example 4 was applied to a base film (2) (untreated PET film, thickness 75 μm, trade name "Lumirror S10#75", manufactured by Toray Industries, Inc.) so that the thickness after drying was 20 μm, and it was cured and dried under conditions of drying temperature 130°C and drying time 30 seconds. A separator (2) (released polyethylene terephthalate film, thickness 38 μm, trade name "MRF#38", manufactured by Mitsubishi Chemical Corporation) was laminated onto the adhesive surface of the obtained urethane adhesive film to protect the urethane adhesive layer.

[0232] <Rating> The double-sided adhesive sheets for transfer obtained in the examples and comparative examples were evaluated as follows. The results are shown in Tables 3 and 4.

[0233] (Catching characteristics) Manufacturing method of silicon wafer; CZ, conductivity type; P, impurity; B, thickness; 750 μm, resistivity; 1 Ωcm to 50 Ωcm, surface; mirror, back surface; mirror, crystal orientation (100), surface impurities Fe, Ni, Cu, Zn, Cr, Al, Na < 1.0 (×1010 atoms / cm 2 )) was backgrinded under the conditions shown in Table 1 below so that the thickness became 500 μm, and a masking material was attached to the wafer surface after backgrinding without allowing air bubbles to be bitten using a hand roller. The Si wafer was attached in such a way as to cover the entire surface with the masking material. Next, ultraviolet rays were irradiated from the base material side of the masking material under the above ultraviolet irradiation conditions to cure the adhesive layer of the masking material. Thereafter, a dicing die bond film (DU2495KS, manufactured by Nitto Denko Corporation) was attached to the back surface side of the wafer. A dicing ring for dicing was attached to the adhesive surface of the dicing tape. After attachment, it was left standing at 22 °C in the dark for 30 minutes. Thereafter, the masking material was peeled off, and blade dicing of the Si wafer and the dicing tape was performed under the conditions shown in Table 2 below to prepare a dicing die bond film in which a plurality of silicon chips of 1 mm square on each side were arranged and fixed.

[0234] <00​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​

[0237] Using the same method, the dicing ring was pasted so that the first adhesive layer of the double-sided adhesive sheet for transfer became the surface, the separator (1) of the first adhesive layer was peeled off, and dicing was performed up to a depth of 30 μm on the surface of the double-sided adhesive sheet using the same method as the conditions shown in Table 2. A transfer double-sided adhesive sheet with markings corresponding to the dicing die bond film on which a plurality of silicon chips with sides of 1 mm square were arranged and fixed was produced.

[0238] The surface on which the silicon chip with an adhesive layer of the dicing die bond film obtained above was fixed was placed downward, and the first adhesive layer of the transfer double-sided adhesive sheet (marked on the first adhesive layer side of the base material) obtained in the examples and comparative examples was placed upward, and arranged to face each other so that the clearance became 1 mm. After aligning the markings, the silicon chip with an adhesive layer on the upper side (from the back side) of the dicing die bond film was pushed with a needle, and 10 were dropped onto the adhesive surface of the first adhesive layer. All the dropped silicon chips were visually checked to confirm whether they fell exactly at the marking positions or fell without turning over, and evaluated according to the following criteria. 〇 ··· All fell without displacement or turning over with respect to all the markings. △ ··· Five or more fell without displacement or turning over with respect to the markings. × ··· All fell with displacement or turned over with respect to all the markings.

[0239] (Adhesive force) <Measurement of the initial adhesive force of the first adhesive layer with respect to the PET film> The transfer double-sided adhesive sheets of the examples and comparative examples were cut into a width of 25 mm and a length of 150 mm to obtain evaluation samples. The separator of the second adhesive layer was peeled off, and the surface of the second adhesive layer was bonded to a glass plate (manufactured by Matsunami Glass Industry Co., Ltd., product name: Micro Slide Glass S). Then, a PET film "product name: Lumirror S10#25 (manufactured by Toray Industries, Inc.)" cut to a width of 20 mm and a length of 100 mm was attached to the first adhesive layer from which the separator had been peeled off by reciprocating 2.0 kg once in an environment of 23°C × 50% RH. After curing for 30 minutes in an environment of 23°C × 50% RH, a universal tensile testing machine (manufactured by Minebea Co., Ltd., product name: TCM-1kNB) was used to peel it at a peeling angle of 180 degrees and a pulling speed of 300 mm / min, and the adhesive strength was measured.

[0240] <Measurement of the adhesive strength of the first adhesive layer with respect to the PET film after 5 minutes at 160°C> The double-sided adhesive sheets for transfer in the examples and comparative examples were cut to a width of 25 mm and a length of 150 mm to obtain evaluation samples. The separator of the second adhesive layer was peeled off, and the surface of the adhesive layer was bonded to a glass plate (manufactured by Matsunami Glass Industry Co., Ltd., product name: Micro Slide Glass S). Then, a PET film "product name: Lumirror S10#25 (manufactured by Toray Industries, Inc.)" cut to a width of 20 mm and a length of 100 mm was attached to the first adhesive layer from which the separator had been peeled off by reciprocating 2.0 kg once in an environment of 23°C × 50% RH. It was cured for 30 minutes in an environment of 23°C × 50% RH. Next, it was heated in an air-circulating constant-temperature oven at 160°C for 5 minutes and taken out. Then, it was allowed to cool for 30 minutes in an environment of 23°C × 50% RH, and a universal tensile testing machine (manufactured by Minebea Co., Ltd., product name: TCM-1kNB) was used to peel it at a peeling angle of 180 degrees and a pulling speed of 300 mm / min, and the adhesive strength was measured.

[0241] <Measurement of the initial adhesive strength of the second adhesive layer with respect to the glass plate> The double-sided sheets for transfer in the examples and comparative examples were cut to a width of 25 mm and a length of 150 mm to obtain evaluation samples. Under conditions of 23°C and 50%RH, the surface of the second adhesive layer, from which the separator of the evaluation sample had been peeled off, was attached to a glass plate (manufactured by Matsunami Glass Industry Co., Ltd., product name: Microslide Glass S) using a 2.0 kg roller in one back-and-forth motion. After curing for 30 minutes under conditions of 23°C and 50%RH, the adhesive strength was measured by peeling the sample using a universal tensile testing machine (manufactured by Minebea Inc., product name: TCM-1kNB) at a peeling angle of 180 degrees and a tensile speed of 300 mm / min.

[0242] <Measurement of adhesive strength of the second adhesive layer on a glass plate after 5 minutes at 160°C> The double-sided adhesive transfer sheets from the examples and comparative examples were cut to a width of 25 mm and a length of 150 mm to be used as evaluation samples. Under conditions of 23°C and 50% RH, the surface of the second adhesive layer from which the separator of the evaluation sample had been removed was attached to a glass plate (manufactured by Matsunami Glass Industry Co., Ltd., product name: Microslide Glass S) using a 2.0 kg roller in one back-and-forth motion. The sample was then cured for 30 minutes under conditions of 23°C and 50% RH. Next, the sample was heated in a 160°C air-circulating constant-temperature oven for 5 minutes and then removed. After that, it was allowed to cool for 30 minutes in an environment of 23°C × 50%RH, and the adhesive strength was measured by peeling it off using a universal tensile testing machine (Minebea Co., Ltd., product name: TCM-1kNB) at a peeling angle of 180 degrees and a tensile speed of 300 mm / min.

[0243] (Tackling power) The double-sided adhesive transfer sheets from the examples and comparative examples were cut to a width of 20 mm and a length of 50 mm to be used as evaluation samples. The adhesive layer surface of the non-measurement side of the evaluation sample was attached to a glass plate (manufactured by Matsunami Glass Industry Co., Ltd., product name: Micro Slide Glass S) using a hand roller. Next, the separator attached to the measurement side was peeled off, and the tack force (gf / 5mmΦSUS) was measured using a tacking tester (manufactured by Resca, product name: TAC-II) under the following conditions. <Measurement conditions> Probe: 5mmφ SUS Push-in / pull-out speed: 120 mm / min Indentation load: 100gf Contact time: 3 seconds

[0244] (Surface force) The double-sided adhesive transfer sheets from the examples and comparative examples were cut to a width of 10 mm and a length of 10 mm to be used as evaluation samples. The adhesive layer surface of the side of the evaluation sample not to be measured was attached to a glass plate (manufactured by Matsunami Glass Industry Co., Ltd., product name: Micro Slide Glass S) using a hand roller. Then, the separator of the side to be measured was peeled off, and the surface force (μN) was measured using an ultra-micro indentation hardness tester (manufactured by ELIONIX, product name: ENT-NEXUS) under the following conditions. <Measurement conditions> Indenter used: Glass ball probe (ELIONIX, diameter: 1mm, BK7) Measurement atmosphere: Under air Measurement temperature: 30℃

[0245] (Surface roughness) A contact optical roughness meter (Zygo New View 7300) was used to measure the adhesive surface of the film with a 50x objective lens and a 2x internal lens (measurement field (XY): 70 μm × 50 μm). After high-pass processing, the Ra, Rz, and Rms values ​​were measured at three locations, and the average value was used as the measurement result.

[0246] (Storage modulus, loss modulus) The first adhesive layer of the double-sided adhesive transfer sheets of the examples and comparative examples was observed and measured using an AFM (Bruker AXS, product name "NanoScope V / Dimension Icon") to determine the storage modulus and loss modulus at 1 Hz and 1 kHz at 25°C, respectively. The measurement mode used was AFM-DMA mode, and the measurements were performed under the following conditions. <Measurement settings> Measurement area: 5μm×5μm Number of measurement points: 32 x 32 Actuator: 1~20kHz sweep

[0247] (Glass reworkability) In the measurement of the adhesive strength of the second adhesive layer to the glass plate after 5 minutes at 160°C, the glass reworkability was judged according to the following criteria. 〇: 3 N / 25 mm or less △: More than 3 N / 25 mm and 5 N / 25 mm or less ×: More than 5 N / 25 mm

[0248] (Transferability) In the measurement of the adhesive strength of the first adhesive layer to the PET film after 5 minutes at 160°C, the transferability was judged according to the following criteria. 〇: 1000 mN / 25 mm or less △: More than 1000 N / 25 mm and less than 5000 mN / 25 mm ×: 5000 mN / 25 mm or more

[0249]

Table 3

[0250]

Table 4

[0251] The variations of the present invention are appended below. [Appendix 1] A double-sided adhesive sheet for transfer in which the first adhesive layer, the base material, and the second adhesive layer are laminated in this order, The first adhesive layer is composed of a low-adhesive strength adhesive layer, The second adhesive layer is composed of a peelable adhesive layer, a double-sided adhesive sheet for transfer. [Appendix 2] The double-sided adhesive sheet for transfer according to Appendix 1, wherein the storage elastic modulus of the first adhesive layer at a frequency of 1 Hz and 25°C by AFM-DMA is 50 MPa or less. [Appendix 3] The double-sided adhesive sheet for transfer according to Appendix 1 or 2, wherein the storage elastic modulus of the first adhesive layer at a frequency of 1 kHz and 25°C by AFM-DMA is 100 MPa or less. [Note 4] A double-sided adhesive sheet for transfer according to any one of Notes 1 to 3, wherein the ratio of the storage modulus of the first adhesive layer at a frequency of 1 kHz and 25°C according to AFM-DMA to the storage modulus of the first adhesive layer at a frequency of 1 Hz and 25°C according to AFM-DMA is greater than 1. [Note 5] The transfer double-sided adhesive sheet according to any one of Notes 1 to 4, wherein the loss modulus of elasticity of the first adhesive layer at a frequency of 1 Hz and 25°C measured by AFM-DMA is 7 MPa or less. [Note 6] A double-sided adhesive sheet for transfer as described in any one of Notes 1 to 5, wherein the tack force of the first adhesive layer against a stainless steel plate (5 mm in diameter) is 10 to 250 gf / Φ5 mm SUS. [Note 7] The base material is a double-sided adhesive sheet for transfer as described in any one of Notes 1 to 6, wherein the base material contains a heat-resistant resin. [Note 8] A method for mounting electronic components onto a mounting substrate, The first adhesive layer of the transfer double-sided adhesive sheet described in any one of appendices 1 to 7 receives the diced electronic component. A method comprising the step of transferring the electronic components received by the first adhesive layer to a mounting substrate. [Note 9] The method according to Note 8, wherein a carrier substrate is attached to the second adhesive layer of the double-sided adhesive sheet for transfer. [Note 10] The method according to Note 8 or 9, wherein the electronic component is a semiconductor chip. [Explanation of Symbols]

[0252] 1. Double-sided adhesive sheet for transfer 10 Base material 11 First adhesive layer 12 Second adhesive layer 110,120 Separator 20 dicing tapes 21 Electronic Components 22 Carrier substrate 23 Pin component 30 Implemented circuit boards 31 Circuit side

Claims

1. A method for mounting electronic components onto a mounting substrate, The process involves the first adhesive layer of a transfer double-sided adhesive sheet, in which a first adhesive layer, a substrate, and a second adhesive layer are laminated in that order, receiving the diced electronic component. The process includes transferring the electronic components received by the first adhesive layer to the mounting substrate, The transfer step includes separating the transfer double-sided adhesive sheet and the mounting substrate, thereby peeling the electronic component from the first adhesive layer and transferring it to the circuit surface of the mounting substrate. The first adhesive layer consists of a low-tack adhesive layer. The second adhesive layer consists of a release adhesive layer. The first adhesive layer is an adhesive layer for receiving and holding electronic components and transferring them to a mounting substrate. The first adhesive layer is composed of one or more adhesives selected from the group consisting of silicone-based adhesives, urethane-based adhesives, acrylic-based adhesives, rubber-based adhesives, polyester-based adhesives, polyamide-based adhesives, epoxy-based adhesives, vinyl alkyl ether-based adhesives, and fluorine-based adhesives. The adhesive strength of the first adhesive layer to the glass plate at 25°C when peeled 180° is 0.1 mN / 25 mm or more. The thickness of the first adhesive layer is 1 μm or more and 100 μm or less. The second adhesive layer is composed of one or more adhesives selected from the group consisting of silicone-based adhesives, urethane-based adhesives, acrylic-based adhesives, rubber-based adhesives, polyester-based adhesives, polyamide-based adhesives, epoxy-based adhesives, vinyl alkyl ether-based adhesives, and fluorine-based adhesives. The method wherein the adhesive strength of the second adhesive layer to the glass plate at 25°C when peeled off at 180° is 1 mN / 25 mm or more and 5000 mN / 25 mm or less.

2. The method according to claim 1, wherein a carrier substrate is attached to the second adhesive layer of the transfer double-sided adhesive sheet.

3. The method according to claim 1 or 2, wherein the electronic component is a semiconductor chip.

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