Transfer printing double-sided adhesive sheet

Abstract

The purpose of this invention is to provide a double-sided adhesive sheet for transfer printing, which is not prone to displacement of electronic components even when exposed to ultraviolet light, thus maintaining transfer accuracy. The double-sided adhesive sheet for transfer printing of the present invention comprises, in sequence, a first adhesive layer, a substrate and a second adhesive layer; the first adhesive layer is composed of a low-adhesion adhesive layer and the second adhesive layer is composed of a release adhesive layer; the first adhesive layer is irradiated with an ultraviolet laser with a beam size of 130×105μm, an output of 100mJ / cm2, a pulse width of 10ns, a frequency of 100Hz and a wavelength of 248nm, and the ratio of the raised height Rz2 after irradiation to the raised height Rz1 before irradiation (Rz2 / Rz1) is 0.2~1600.

Description

[Technical Field]

[0001] This invention relates to a double-sided adhesive sheet for transfer printing. [Previous Technology]

[0002] Conventionally, in the manufacturing process of semiconductor devices, a transfer double-sided adhesive sheet on a carrier substrate receives the semiconductor wafer after it has been monolithized into a semiconductor chip, and then transfers it onto a mounting substrate (e.g., Patent Document 1). Previous Art Documents Patent Documents

[0003] Patent Document 1: Japanese Patent Application Publication No. 2005-263876 [Summary of the Invention]

[0004] The problem to be solved by the invention: In the manufacturing process of semiconductor devices, etc., in order to give identification when transporting and receiving double-sided adhesive sheets for transfer containing semiconductor wafers, there are cases where the double-sided adhesive sheets for transfer are marked. However, if ultraviolet laser is used on the marking, as shown in FIG5, the first adhesive layer 12 will peel off from the substrate 10 and float up, causing damage to the flatness of the double-sided adhesive sheet for transfer, which may lead to the positional displacement of electronic components 21 or easily cause transfer defects.

[0005] The present invention was made in view of the above-mentioned problems, and its purpose is to provide a double-sided adhesive sheet for transfer printing, which is not prone to displacement of electronic components even when exposed to ultraviolet light, and can maintain transfer accuracy.

[0006] Means for Solving the Problem: The inventors have diligently researched and developed methods to achieve the aforementioned objective. They discovered that by using the following double-sided adhesive transfer sheet, even when marking is performed under ultraviolet light, positional misalignment or poor transfer of electronic components can be suppressed. This double-sided adhesive transfer sheet comprises: a first adhesive layer for receiving fine electronic components such as semiconductor wafers, a substrate, and a second adhesive layer for temporarily fixing it to a carrier substrate. Furthermore, the ratio of the raised surface height before irradiation with a specific ultraviolet laser to the raised surface height after irradiation is within a specific range. This invention is based on these insights and knowledge.

[0007] That is, the present invention provides a double-sided adhesive sheet for transfer printing, which is composed of a first adhesive layer, a substrate and a second adhesive layer in sequence; the first adhesive layer is composed of a low-adhesion adhesive layer and the second adhesive layer is composed of a peelable adhesive layer; the first adhesive layer is irradiated with an ultraviolet laser with a beam size of 130×105µm, an output of 100mJ / cm2, a frequency of 100Hz, a pulse width of 10ns and a wavelength of 248nm, and the ratio of the relief height Rz1 before irradiation to the relief height Rz2 after irradiation (Rz1 / Rz2) is 0.2~1600.

[0008] After the first adhesive layer is irradiated with an ultraviolet laser with a beam size of 130×105µm, an output of 100mJ / cm2, a frequency of 100Hz, a pulse width of 10ns and a wavelength of 248nm, the area ratio of the raised area to the irradiated area should be less than 20.0%.

[0009] The present invention further provides a double-sided adhesive sheet for transfer printing, which consists of a first adhesive layer, a substrate and a second adhesive layer sequentially laminated; the first adhesive layer is composed of a low-adhesion adhesive layer and the second adhesive layer is composed of a release adhesive layer; after irradiating the first adhesive layer with an ultraviolet laser with a beam size of 130×105µm, an output of 100mJ / cm2, a pulse width of 10ns and a frequency of 100Hz and a wavelength of 248nm, the area ratio of the raised area to the total irradiated area is 20.0% or less.

[0010] The ratio (Rz2 / t1) of the above-mentioned convex height Rz2 (µm) to the thickness t1 (µm) of the above-mentioned first adhesive layer should preferably be 1.0 or less.

[0011] Effects of the invention The double-sided adhesive sheet for transfer printing of the present invention is not easily damaged even when irradiated with ultraviolet laser. Therefore, it can suppress the positional displacement of electronic components or poor transfer and maintain the transfer accuracy.

Implementation Method

[0013] [Double-sided adhesive sheet for transfer printing] An embodiment of the double-sided adhesive sheet for transfer printing of the present invention has a laminated structure in which a first adhesive layer, a substrate, and a second adhesive layer are sequentially stacked. The first adhesive layer is irradiated with an ultraviolet laser with a beam size of 130×105µm, an output of 100mJ / cm2, a frequency of 100Hz, a pulse width of 10ns, and a wavelength of 248nm. The ratio (Rz1 / Rz2) of the raised height Rz1 before irradiation to the raised height Rz2 after irradiation is 0.2~1600. Regarding one embodiment of the double-sided adhesive sheet for transfer printing of the present invention, there are instances where reference numerals are drawn and the following description is provided; however, the double-sided adhesive sheet for transfer printing of the present invention is not limited to this embodiment. Figure 1 is a cross-sectional schematic diagram showing one embodiment of the double-sided adhesive sheet for transfer printing according to the present invention. 1 represents the double-sided adhesive sheet for transfer printing, 10 represents the substrate, 11 represents the first adhesive layer, and 12 represents the second adhesive layer.

[0014] From the viewpoint of the positional accuracy of the electronic components received by the first adhesive layer, it is preferable that the ratio (Rz1 / Rz2) is 0.2 to 1600, more preferably 0.4 to 1500, and even more preferably 0.5 to 1400. Furthermore, the convexity heights Rz1 and Rz2 are the maximum height of the bulge in the vertical direction (Z-axis direction) of the irradiated part after laser irradiation, and can be obtained, for example, by analyzing the surface observation image obtained using a laser microscope (product name "VK-X100", manufactured by KEYENCE).

[0015] In the double-sided adhesive sheet for transfer printing of the present invention, after irradiating the first adhesive layer with an ultraviolet laser of wavelength 248nm with a beam size of 130×105µm, an output of 100mJ / cm2, a frequency of 100Hz, and a pulse width of 10ns, the area ratio of the raised area to the irradiated area is preferably 20.0% or less. From the viewpoint of the positional accuracy of the electronic components received by the first adhesive layer, it is preferable that the above-mentioned area ratio is 20.0% or less, more preferably 15.0% or less, and even more preferably 10.0% or less. The lower limit of the above-mentioned area ratio is usually 0%. Furthermore, the raised area is the area of ​​the portion of the low-adhesion adhesive layer that is peeled off from the substrate and raised, and can be obtained, for example, by analyzing a surface observation image taken using a microscope.

[0016] In the double-sided adhesive sheet for transfer printing of the present invention, the ratio (Rz2 / t1) of the aforementioned raised height Rz2 (µm) to the thickness t1 (µm) of the aforementioned first adhesive layer is preferably 1.0 or less. From the viewpoint of the positional accuracy of the electronic components received by the aforementioned first adhesive layer, it is preferable that the aforementioned ratio (Rz2 / t1) is 1.0 or less, more preferably 0.5 or less, and even more preferably 0.4 or less.

[0017] The height Rz2 or the area ratio of the raised surface after ultraviolet laser irradiation can be adjusted by adjusting the following: adjusting the type or composition of the adhesive constituting the first adhesive layer, the degree of cross-linking, etc. to adjust the adhesion, and adjusting the type or amount of ultraviolet absorber to suppress the reaction of the substrate, or adjusting the adhesion between the adhesive and the substrate.

[0018] Another embodiment of the present invention provides a double-sided adhesive sheet for transfer printing, having a laminated structure in which a first adhesive layer, a substrate, and a second adhesive layer are sequentially stacked. After irradiating the first adhesive layer with an ultraviolet laser of 248nm wavelength and a beam size of 130×105µm, an output of 100mJ / cm², a frequency of 100Hz, and a pulse width of 10ns, the area ratio of the raised area to the irradiated area is 20.0% or less. By achieving this area ratio of 20.0% or less, the positional accuracy of electronic components can be maintained. The area ratio is preferably 15.0% or less, and more preferably 10.0% or less.

[0019] <First Adhesive Layer> In the double-sided adhesive sheet for transfer printing of the present invention, the first adhesive layer is an adhesive layer used to receive and hold electronic components, and it is composed of a low-tack adhesive layer. The first adhesive layer being composed of a low-tack adhesive layer has the following advantages: it reduces the force applied to the electronic components during reception, thus suppressing damage to the electronic components. Furthermore, when the first adhesive layer receives the electronic components without contact, for example, by using a pin member to push the electronic components off the cutting tape, causing them to fall onto the first adhesive layer. However, when the first adhesive layer receives the falling electronic components, there are instances where the falling electronic components bounce and cannot be accurately received. When this phenomenon occurs, the positional accuracy of the electronic components decreases, resulting in poor contact. The aforementioned first adhesive layer is composed of a low-adhesion adhesive layer. This configuration allows the electronic components to be received by the first adhesive layer without contact with them, preventing them from bouncing and ensuring precise positioning. Furthermore, when mounting the electronic components received by the transfer double-sided adhesive sheet onto the mounting substrate, the electronic components can be easily peeled off from the first adhesive layer, which is also advantageous.

[0020] The first adhesive layer described above can be formed by adjusting the type or composition of the adhesive, the degree of crosslinking, etc., or by mixing in a light peeling agent or plasticizer to form a WBL (Weak Boundary Layer) to produce a low-tack adhesive layer.

[0021] There is no particular limitation on the 180° peel adhesion of the first adhesive layer to the PET film at 25°C. From the viewpoint of ensuring accurate positioning without damaging electronic components and good transferability to the mounting substrate, it is preferable to have an adhesion of 100 mN / 25 mm or less, more preferably 50 mN / 25 mm or less, and even more preferably 10 mN / 25 mm. Furthermore, from the viewpoint of the adhesion of electronic components to the first adhesive layer, the 180° peel adhesion of the first adhesive layer to the glass plate at 25°C is preferably 0.1 mN / 25 mm or more, and more preferably 1 mN / 25 mm or more.

[0022] The ratio (P1b / P1a) of the first adhesive layer's 180° peel adhesion to the PET film at 25°C (hereinafter sometimes referred to as "P1a" in this specification) after holding the transfer double-sided adhesive sheet at 160°C for 5 minutes is not particularly limited, but is preferably 3.0 or less, and more preferably 2.5 or less. A P1b / P1a ratio of 3.0 or less is preferred because when electronic components received by the transfer double-sided adhesive sheet of the present invention are heat-pressed onto a mounting substrate for mounting, the adhesion of the first adhesive layer to the electronic components is not increased, and the components can be well peeled off and transferred onto the mounting substrate.

[0023] The above-mentioned 180° peel adhesion at 25°C is achieved by bonding the second adhesive layer of the transfer double-sided adhesive sheet to a glass plate, and bonding a PET film to the adhesive side of the first adhesive layer. After pressing with a 2kg roller for one round trip, the sheet is cured for 30 minutes at 23°C and 50%RH. After curing, according to JIS Z0237, the transfer double-sided adhesive sheet is peeled off from the substrate at a stretching speed of 300mm / min and a peel angle of 180° at 25°C and 50%RH, and the 180° peel adhesion (mN / 25mm) is measured. There are no particular limitations if the PET film is untreated PET; for example, the trade name "Lumirror #25-S10 Thickness 23µm" (TORAY Corporation).

[0024] The surface force of the first adhesive layer can be adjusted by the type or composition of the adhesive, the degree of cross-linking, and additives such as fatty acid esters or fluorinated surfactants.

[0025] In the double-sided adhesive sheet for transfer printing of the present invention, the storage modulus (E'1a) of the first adhesive layer at a frequency of 1 Hz and a temperature of 25°C, obtained using AFM-DMA, is preferably 50 MPa or less. This configuration is preferable for reliably adhering to the electronic components received by the first adhesive layer. If E'1a is too high, the adhesion of the electronic components to the first adhesive layer will decrease, and there may be adverse situations such as displacement or falling of the electronic components. From the viewpoint of the adhesion of the electronic components to the first adhesive layer, E'1a is preferably 40 MPa or less, and more preferably 30 MPa or less. It can also be 20 MPa or less, or 10 MPa or less. On the other hand, from the viewpoint of the transferability of 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 will become too high, which may impair the transferability when mounted on the mounting substrate. From the perspective of the transferability of electronic components to the mounting substrate, E'1a should preferably be 0.2 MPa or higher, and more preferably 0.5 MPa or higher.

[0026] In the double-sided adhesive sheet for transfer printing of the present invention, the storage modulus (E'1b) of the first adhesive layer obtained by AFM-DMA at a frequency of 1 kHz and a temperature of 25°C is preferably 100 MPa or less. This configuration is advantageous because when the first adhesive layer is received without contacting the electronic components, the electronic components will not be bounced off the surface of the first adhesive layer, and can be received with precise positioning. If E'1b is too high, when the electronic components are received without contacting them and the material is dropped onto the surface of the first adhesive layer, the electronic components may be bounced off and shift from their predetermined position, or flip over, thus easily reducing positional accuracy. From the viewpoint of the positional accuracy of the electronic components on the first adhesive layer, E'1b is preferably 90 MPa or less, and more preferably 80 MPa or less. Furthermore, the pressure can 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 the transferability of the first adhesive layer to the mounting substrate, E'1b should preferably be 0.5 MPa or more. If E'1b is too low, the adhesion of the electronic component to the first adhesive layer will be high, and the electronic component may be buried in the first adhesive layer when it falls, which will impair the transferability when mounted on the mounting substrate. From the viewpoint of the transferability of the electronic component to the mounting substrate, E'1b should preferably be 0.7 MPa or more, and more preferably 1.0 MPa or more.

[0027] In the double-sided adhesive sheet for transfer of the present invention, the ratio (E'1b / E'1a) of the storage modulus of elasticity (E'1b) of the first adhesive layer obtained by AFM-DMA at a frequency of 1 kHz and a temperature of 25°C to the storage modulus of elasticity (E'1a) of the first adhesive layer obtained by AFM-DMA at a frequency of 1 Hz and a temperature of 25°C is preferably greater than 1.00. This configuration has the following advantages: the balance between the adhesion of electronic components to the first adhesive layer, positional accuracy, and transferability to the mounting substrate is improved. From the viewpoint of balancing the 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 1.10 or more. There is no particular upper limit to E'1b / E'1a, but from the above-mentioned balance point of view, it is preferably 3.00 or less.

[0028] In the double-sided adhesive sheet for transfer printing of the present invention, the loss modulus (E”1a) of the first adhesive layer obtained by AFM-DMA at a frequency of 1 Hz and a temperature of 25°C is preferably 7 MPa or less. From the viewpoint of excellent transferability of electronic components to mounting substrates, this configuration is preferred. If E”1a is too high, the adhesion of the electronic components to the first adhesive layer will become too high, which may impair the transferability when mounted on the mounting substrate. From the viewpoint of transferability of electronic components to mounting substrates, 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 will decrease, which may lead to adverse situations such as displacement or falling of the electronic components. From the perspective of the adhesion of electronic components to the first adhesive layer, E”1a should preferably be 0.01 MPa or higher, and more preferably 0.03 MPa or higher.

[0029] The storage elastic modulus (E'1a) at 1 Hz and 25°C, the storage elastic modulus (E'1b) at 1 kHz and 25°C, and the loss elastic modulus (E”1a) at 1 Hz and 25°C obtained by AFM-DMA (atomic force microscopy (AFM: nano dynamic mechanical analysis)) of the first adhesive layer can be adjusted by the type or composition of the adhesive, the degree of crosslinking, etc.

[0030] In the double-sided adhesive sheet for transfer printing of the present invention, the adhesion of the first adhesive layer to the stainless steel plate (5mm in diameter) is preferably 10~250gf / Φ5mmSUS. From the viewpoint of the adhesion and positional accuracy of the first adhesive layer to the electronic components, it is preferable that the adhesion is 10gf / Φ5mmSUS or more, and more preferably 20gf / Φ5mmSUS or more. On the other hand, from the viewpoint of the transferability of the electronic components to the mounting substrate, it is preferable that the adhesion is 250gf / Φ5mmSUS or less, and more preferably 200gf / Φ5mmSUS or less.

[0031] The adhesion of the first adhesive layer to the stainless steel plate (5mm in diameter) can be adjusted by the type or composition of the adhesive, the degree of cross-linking, and additives such as fatty acid esters or fluorinated surfactants.

[0032] In the double-sided adhesive sheet for transfer printing of the present invention, the surface force of the first adhesive layer is preferably -500 to -100µN. From the viewpoint of the adhesion and positional accuracy of the electronic components to the first adhesive layer, it is preferable that the surface force is -500µN or more, and more preferably -400µN or more. On the other hand, from the viewpoint of the transferability of electronic components to the mounting substrate, it is preferable that the surface force is -100µN or less, and more preferably -150µN or less.

[0033] The surface force of the first adhesive layer can be adjusted by the type or composition of the adhesive, the degree of cross-linking, and additives such as fatty acid esters or fluorinated surfactants.

[0034] In the double-sided adhesive sheet for transfer printing of the present invention, the thickness t1 of the first adhesive layer is not particularly limited, but is preferably 1µm or more, and more preferably 3µm or more. If the thickness is above a certain value, the first adhesive layer can easily and accurately receive electronic components, which is ideal. Furthermore, the upper limit of the thickness t1 of the first adhesive layer is not particularly limited, but is preferably 100µm, more preferably 90µm, and even more preferably 80µm, 70µm, 60µm, or 50µm. It is also more preferably 45µm, 40µm, 35µm, 30µm, 25µm, 20µm, 15µm, or 0µm. If the thickness is below a certain value, it is easy and accurate to transfer electronic components onto the mounting substrate, which is ideal.

[0035] In the double-sided adhesive sheet for transfer printing 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. If the haze is 10% or less, excellent transparency can be obtained. For example, after the double-sided adhesive sheet for transfer printing is attached to the carrier substrate, the pattern attached to the carrier substrate (e.g., a mark indicating the transfer position of electronic components) can be seen, which is ideal. In addition, the above-mentioned haze can be measured, for example, by forming the first adhesive layer on the separator and letting it stand at normal temperature (23°C, 50%RH) for at least 24 hours, peeling off the separator and attaching it to a glass slide (e.g., with a total light transmittance of 91.8% and a haze of 0.4%) to make a sample, and then measuring it using a haze meter (product name "HM-150", manufactured by Murakami Color Technology Research Institute).

[0036] In the double-sided adhesive sheet for transfer of the present invention, the total light transmittance (according to JIS K7361-1) of the first adhesive layer in the visible light wavelength region is not particularly limited, but is preferably 85% or more, and more preferably 88% or more. If the total light transmittance is 85% or more, excellent transparency can be obtained. For example, after the double-sided adhesive sheet for transfer is attached to the carrier substrate, the pattern attached to the carrier substrate (e.g., a mark indicating the transfer position of an electronic component) can be seen, which is ideal. In addition, the above-mentioned total light transmittance can be measured, for example, by forming the first adhesive layer on the separator and letting it stand at normal temperature (23°C, 50%RH) for at least 24 hours, peeling off the separator and attaching it to a glass slide (e.g., with a total light transmittance of 91.8% and a haze of 0.4%) to make a sample, and then measuring it using a haze meter (product name "HM-150", manufactured by Murakami Color Technology Research Institute).

[0037] The adhesive composition constituting the first adhesive layer is not particularly limited, and may include, for example, polysiloxane adhesives, urethane adhesives, acrylic adhesives, rubber adhesives, polyester adhesives, polyamide adhesives, epoxy adhesives, vinyl alkyl ether adhesives, fluorinated adhesives, etc. From the viewpoint of accurately receiving the electronic components without damaging them and having good transfer properties to the mounting substrate, polysiloxane adhesives, urethane adhesives, and acrylic adhesives that are easy to control to have low adhesion and low tack are preferable, polysiloxane adhesives and urethane adhesives are more preferable, and polysiloxane adhesives are more preferable.

[0038] (Polysiloxane adhesive) There are no particular restrictions on the polysiloxane adhesive; any known or conventional polysiloxane adhesive may be used, such as addition-type polysiloxane adhesives, peroxide-cured polysiloxane adhesives, and condensation-type polysiloxane adhesives. The polysiloxane adhesive may be either a single-component or a two-component type. The polysiloxane adhesive may be used alone or in combination of two or more types.

[0039] The above-mentioned addition-type polysiloxane adhesives are generally adhesives that generate polysiloxane polymers by using a platinum compound catalyst such as chloroplatinic(IV) acid to allow an addition reaction (hydrosiliconization reaction) between an organopolysiloxane having vinyl or other alkenyl groups on its silicon atoms and an organopolysiloxane having hydrosilicone groups. Peroxide-curable polysiloxane adhesives are generally adhesives that generate polysiloxane polymers by using a peroxide to harden (crosslink) the organopolysiloxane. Furthermore, condensation-type polysiloxane adhesives are generally adhesives that generate polysiloxane polymers through a dehydration or dealcoholization reaction between polyorganosiloxanes with hydrolyzable silicon groups such as silanol or alkoxysilyl groups at the ends.

[0040] From the perspective of being easy to control to have low adhesion and low viscosity, polysiloxane adhesives can be exemplified by polysiloxane adhesives containing polysiloxane rubber and polysiloxane resin.

[0041] There are no particular restrictions on the composition of the above-mentioned polysiloxane rubber if it is a polysiloxane-based rubber. For example, organic polysiloxanes with dimethylsiloxane, methylphenylsiloxane, etc., as the main constituent units can be used. Furthermore, depending on the reaction type, the following can be used: polysiloxane rubbers having alkenyl groups bonded to silicon atoms (organic polysiloxanes containing alkenyl groups; when it is an addition reaction type), polysiloxane rubbers having at least methyl groups (when it is a peroxide curing type), and polysiloxane rubbers having silanol groups or hydrolyzable alkoxysilyl groups at the ends (when it is a condensation type). In addition, the weight average molecular weight of the organic polysiloxane in the polysiloxane rubber is usually 150,000 or more, preferably 280,000 to 1,000,000, and particularly preferably 500,000 to 900,000.

[0042] Furthermore, there are no particular limitations on the polysiloxane resin used in polysiloxane adhesives. Examples include polysiloxane resins composed of organosiloxanes, wherein the organosiloxane is composed of a (co)polymer having at least one of the following units: an M unit composed of the constitutive unit "R3Si1 / 2", a Q unit composed of the constitutive unit "SiO2", a T unit composed of the constitutive unit "RSiO3 / 2", and a D unit composed of the constitutive unit "R2SiO". In addition, R in the above-mentioned constitutive units represents a hydrocarbon group or a hydroxyl group. Examples of the above-mentioned hydrocarbon groups include aliphatic hydrocarbon groups (alkyl groups such as methyl and ethyl), alicyclic hydrocarbon groups (cycloalkyl groups such as cyclohexyl), and aromatic hydrocarbon groups (aryl groups such as phenyl and naphthyl). The ratio of the M unit to at least one unit selected from the Q, T, and D units is preferably, for example, a molar ratio of approximately 0.3 / 1 to 1.5 / 1 (preferably 0.5 / 1 to 1.3 / 1). Various functional groups, such as vinyl groups, may also be incorporated into the organopolysiloxane in the polysiloxane as needed. Furthermore, the incorporated functional groups may be functional groups capable of cross-linking reactions. The polysiloxane is preferably an MQ resin composed of M and Q units. The weight-average molecular weight of the organopolysiloxane in the polysiloxane is typically 1000 or higher, preferably 1000 to 20000, and particularly preferably 1500 to 10000.

[0043] There are no particular restrictions on the mixing ratio of polysiloxane rubber and polysiloxane resin. From the point of view, it is easy to control it to have low adhesion and low viscosity. For example, relative to 100 parts by weight of polysiloxane rubber, the polysiloxane resin should be 100 to 220 parts by weight (especially 120 to 180 parts by weight).

[0044] In addition, in polysiloxane adhesives containing polysiloxane rubber and polysiloxane resin, the polysiloxane rubber and polysiloxane resin may be in a mixed state where they are simply mixed, or they may react with each other to become condensates (especially partial condensates), crosslinking reactants, addition reaction products, etc.

[0045] Furthermore, considering the ease of controlling low adhesion and low viscosity, polysiloxane adhesives containing polysiloxane rubber and polysiloxane resin typically include a crosslinking agent in order to form a crosslinked structure. The crosslinking agent is not particularly limited and can be either a silicone-based crosslinking agent (polysiloxane crosslinking agent) or a peroxide-based crosslinking agent. The crosslinking agent can be used alone or in combination of two or more types.

[0046] The aforementioned siloxane-based crosslinking agent is, for example, a polyorganohydrosiloxane having two or more hydrogen atoms bonded to silicon atoms in its molecule. In the polyorganohydrosiloxane, various organic groups may be bonded to the silicon atoms bonded to hydrogen atoms, in addition to hydrogen atoms. Examples of such organic groups include alkyl groups such as methyl and ethyl; aryl groups such as phenyl; and halogenated alkyl groups, etc. From a synthetic or processing point of view, methyl is preferable. Furthermore, the skeletal structure of the polyorganohydrosiloxane may also have any of the following: linear, branched, or cyclic skeletal structures, but linear is preferable.

[0047] The above-mentioned peroxide-based crosslinking agents may include, for example, diacyl peroxide, alkyl peroxide, peroxydicarbonate, monoperoxycarbonate, peroxyketal, dialkyl peroxide, hydroperoxide, ketone peroxide, etc. More specifically, examples include: benzoyl peroxide, tributyl peroxybenzoate, diisopropylphenyl peroxide, tributylisopropylphenyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di-tert-butylperoxyhexane, 2,4-dichloro-benzoyl peroxide, di-tert-butylperoxy-diisopropylbenzene, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di-tert-butylperoxyhexyne-3, etc.

[0048] Addition-type polysiloxane adhesives, for example, are commercially available under the trade 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.). Also, peroxide-cured polysiloxane adhesives, for example, are commercially available under the trade names "KR-100", "KR-101-10", and "KR-130" (all manufactured by Shin-Etsu Chemical Co., Ltd.).

[0049] The above-mentioned addition-type polysiloxane adhesive should preferably include a curing catalyst such as a platinum catalyst. Commercially available platinum catalysts include, for example, "CAT-PL-50T" (manufactured by Shin-Etsu Chemical Co., Ltd.), "DOWSIL NC-25 Catalyst," and "DOWSIL SRX212 Catalyst" (both manufactured by Dow Toray Co., Ltd.). From the perspective of balancing the acceptability, positional accuracy, transferability to the mounting substrate, and adhesion of the electronic components in the first adhesive layer, the content of the curing catalyst should preferably be approximately 0.1 to 10 parts by weight relative to 100 parts by weight of the polysiloxane polymer (including polysiloxane rubber, polysiloxane resin, etc.) used as the base polymer.

[0050] (Carbamate adhesives) There are no particular restrictions on carbamate adhesives. Known or even commonly used carbamate adhesives can be used. From the point of view that it is easy to control to low tack and low viscosity, carbamate adhesives containing polyols, polyfunctional isocyanate compounds and catalysts are preferred.

[0051] There is no particular limitation on the polyol having two or more hydroxyl groups; any suitable polyol may be used. Examples of such polyols include: polyols with two hydroxyl groups (diols), polyols with three hydroxyl groups (triols), polyols with four hydroxyl groups (tetraols), polyols with five hydroxyl groups (pentaols), and polyols with six hydroxyl groups (hexaols). Polyols may be used alone or in combination of two or more.

[0052] The aforementioned polyols preferably include polyols with a number average molecular weight (Mn) of 400 to 20,000. Furthermore, the proportion of polyols with a number average molecular weight (Mn) of 400 to 20,000 in the total amount of polyols 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 proportion of polyols with a number average molecular weight (Mn) of 400 to 20,000 in the polyols to the above range, for example, a carbamate-based adhesive that has been controlled to have low tackiness and low viscosity can be provided.

[0053] The above-mentioned polyols may include, for example, polyester polyols, polyether polyols, polycaprolactone polyols, polycarbonate polyols, castor oil-based polyols, etc.

[0054] The above-mentioned polyester polyol can be obtained, for example, by esterification reaction of polyol component and acid component.

[0055] The above-mentioned polyol components can be listed as follows: ethylene glycol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-but-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, glycerol, trimethylolpropane, neopentyl tertrol, hexanediol, polypropylene glycol, etc.

[0056] The above-mentioned acid components may include, for example: succinic acid, methylsuccinic acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 1,12-dodecanoic acid, 1,14-tetradecanoic acid, dicarboxylic acid, 2-methyl-1,4-cyclohexanedicarboxylic acid, 2-ethyl-1,4-cyclohexanedicarboxylic acid, p-phthalic acid, isophthalic acid, phthalic acid, isophthalic acid, p-phthalic acid, 1,4-naphthalenedicarboxylic acid, 4,4'-biphenyl dicarboxylic acid, and their anhydrides.

[0057] Examples of the aforementioned polyether polyols include those obtained by addition polymerization of olefin oxides such as ethylene oxide, propylene oxide, and butene oxide using water, low molecular weight polyols (propylene glycol, ethylene glycol, glycerol, trimethylolpropane, neopentyl terephthalol, etc.), bisphenols (bisphenol A, etc.), and dihydroxybenzenes (catechol, resorcinol, hydroquinone, etc.) as initiators. Specifically, examples include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

[0058] The above-mentioned polycaprolactone polyols can be exemplified by cyclic ester monomers such as ε-caprolactone and σ-valerol, which are obtained by ring-opening polymerization of caprolactone-based polyester diols.

[0059] Examples of the above-mentioned polycarbonate polyols include: polycarbonate polyols obtained by condensation polymerization of the above-mentioned polyol components with phosgene; polycarbonate polyols obtained by transesterification condensation of the above-mentioned polyol components with dimethyl carbonate, diethyl carbonate, dipropyl carbonate, diisopropyl carbonate, dibutyl carbonate, ethylbutyl carbonate, ethylbenzyl carbonate, propylbenzyl carbonate, diphenyl carbonate, dibenzyl carbonate, etc.; and copolymerized polycarbonate polyols obtained by using two or more of the above-mentioned polyol components; and polycarbonate polyols combined with carboxyl-containing compounds. Polycarbonate polyols obtained by esterification reaction of the above-mentioned polycarbonate polyols and hydroxyl-containing compounds through etherification reaction; polycarbonate polyols obtained by transesterification reaction of the above-mentioned polycarbonate polyols and ester compounds; polycarbonate polyols obtained by transesterification reaction of the above-mentioned polycarbonate polyols and hydroxyl-containing compounds through transesterification reaction; polyester-based polycarbonate polyols obtained by condensation polymerization reaction of the above-mentioned polycarbonate polyols and dicarboxylic acid compounds; and copolymer polyether-based polycarbonate polyols obtained by copolymerization of the above-mentioned polycarbonate polyols and olefin oxides, etc.

[0060] The castor oil polyols mentioned above can be exemplified by the reaction of castor oil fatty acids with the aforementioned polyol components to obtain castor oil-based polyols. Specifically, castor oil-based polyols can be exemplified by the reaction of castor oil fatty acids with polypropylene glycol.

[0061] From the viewpoint of low adhesion, low viscosity, and wettability of the first adhesive layer to electronic components, it is preferable to use a polyol with three hydroxyl groups (triol) as an essential component. The content of the polyol with three hydroxyl groups (triol) should preferably be 50-100% by weight, and more preferably 70-100% by weight, relative to the total amount of components constituting the polyol.

[0062] Examples of the above-mentioned polyfunctional isocyanate compounds include aliphatic polyisocyanates, alicyclic polyisocyanates, and aromatic polyisocyanate compounds.

[0063] Examples of the above-mentioned aliphatic polyisocyanates include: trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-endenylpropyl diisocyanate, 1,3-endenylbutyl diisocyanate, dodecamethyl diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, etc.

[0064] Examples of the above-mentioned alicyclic polyisocyanates include: 1,3-cyclopentene diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, isoflavone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated benzoyl diisocyanate, toluene hydrogenated diisocyanate, and hydrogenated tetramethyl benzoyl diisocyanate.

[0065] Examples of the above-mentioned aromatic polyisocyanates include: phenylene diisocyanate, toluene 2,4-diisocyanate, toluene 2,6-diisocyanate, 2,2'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, phenylene diisocyanate, etc.

[0066] Among them, aliphatic polyisocyanates and their modified products are preferred. Compared with other isocyanate-based crosslinking agents, aliphatic polyisocyanates and their modified products have better flexibility in crosslinking structures and are easier to control to achieve low adhesion and low viscosity. Hexamethylene diisocyanate and its modified products are particularly preferred.

[0067] From the viewpoint of the low adhesion, low viscosity, and wettability of the first adhesive layer to electronic components, the equivalent ratio (NCO / OH) of the isocyanate group of the polyfunctional isocyanate compound and the hydroxyl group of the polyol is preferably 1 to 5, more preferably 1.1 to 3, and even more preferably 1.2 to 2.

[0068] The above-mentioned carbamate adhesives preferably contain catalysts such as iron-based compounds and / or tin-based compounds. Specific examples include: tin-based catalysts such as dibutyltin dilaurate and dioctyltin dilaurate; iron acetone (acetophenone); iron hexane-2,4-dione; iron hepta-2,4-dione; iron hepta-3,5-dione; iron 5-methylhexane-2,4-dione; iron octane-2,4-dione; iron 6-methylhepta-2,4-dione; iron 2,6-dimethylhepta-3,5-dione; iron nonanone-2,4-dione; iron nonanone-4,6-dione; iron 2,2,6,6-tetramethylhepta-3,5-dione; iron tridecane-6,8-dione; iron 1-phenylbutanone-1,3-dione; and iron hexafluoroacetone. Iron-based catalysts include iron in the following forms: acetone (acetone), ethyl acetate (acetyl acetate), propyl acetate (acetyl acetate), isopropyl acetate (acetyl acetate), butyl acetate (acetyl acetate), butyl acetyl acetate (acetyl acetate), butyl acetate (acetyl acetate), methyl acetate (acetyl acetate), ethyl acetate (acetyl acetate), propyl acetate (acetyl acetate), isopropyl acetate (acetyl acetate), butyl acetate (acetyl acetate), butyl acetate (acetyl acetate), butyl acetate (acetyl acetate), benzyl acetate (acetyl acetate), dimethyl malonate (acetyl acetate), diethyl malonate (acetyl acetate), trimethoxy iron, triethoxy iron, triisopropoxy iron, and ferric chloride.

[0069] Relative to 100 parts by weight of polyol, the content (amount) of catalyst contained in the above-mentioned carbamate-based adhesive 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. Within this range, the crosslinking reaction is faster when the adhesive layer is formed, and the shelf life of the adhesive composition is also longer, which is ideal.

[0070] Furthermore, considering that it is easy to control to achieve low adhesion and low viscosity, urethane adhesives should also be urethane adhesives containing urethane prepolymers.

[0071] Examples of urethane-based adhesives containing urethane prepolymers include adhesives containing polyurethane polyols as urethane prepolymers and polyfunctional isocyanate compounds. The urethane prepolymer can be used alone or in combination of two or more. The polyfunctional isocyanate compound can be used alone or in combination of two or more.

[0072] The polyurethane polyol used as a prepolymer is preferably formed by reacting a polyester polyol with a polyether polyol and an organic polyisocyanate compound in the presence or absence of a catalyst.

[0073] Any suitable polyester polyol may be used. Examples of polyester polyols include those obtained by reacting an acidic component with a glycol component. Examples of acidic components include phthalic acid, adipic acid, azelaic acid, sebacic acid, phthalic anhydride, isophthalic acid, trimellitic acid, etc. Examples of glycol components include ethylene glycol, propylene glycol, diethylene glycol, butanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 3,3'-dimethylolheptane, polyoxyethylene glycol, polyoxypropylene glycol, 1,4-butanediol, neopentyl glycol, butylethylpentanediol; examples of polyol components include glycerol, trimethylolpropane, neopentyl tertrol, etc. In addition, polyester polyols may also include those obtained by ring-opening polymerization of lactones such as polycaprolactone, poly(β-methyl-γ-valactone), and polyvalactone.

[0074] Polyester polyols can be used in a range of molecular weights from low to high. Regarding the molecular weight of the polyester polyol, the number average molecular weight should preferably be between 500 and 5000. If the number average molecular weight is less than 500, there is a risk of increased reactivity and easy gelation. If the number average molecular weight is greater than 5000, there is a risk of decreased reactivity and consequently, a decrease in the agglomeration power of the polyurethane polyol itself. The amount of polyester polyol used should preferably be 10 to 90 mol% of the polyol constituting the polyurethane polyol.

[0075] Any suitable polyether polyol may be used. Examples of such polyether polyols include those obtained by polymerizing ethylene oxide, propylene oxide, butene oxide, tetrahydrofuran, and other ethylene oxide compounds using low molecular weight polyols such as water, propylene glycol, ethylene glycol, glycerol, and trimethylolpropane as initiators. Specifically, examples of such polyether polyols include polypropylene glycol, polyethylene glycol, and polytetramethylene glycol, which have a functional group number of 2 or more.

[0076] Polyether polyols can be used in a range of molecular weights from low to high. Regarding the molecular weight of the polyether polyol, the number average molecular weight should preferably be between 1000 and 5000. If the number average molecular weight is less than 1000, there is a risk of increased reactivity and easy gelation. If the number average molecular weight is greater than 5000, there is a risk of decreased reactivity and consequently, a decrease in the agglomeration power of the polyurethane polyol itself. The amount of polyether polyol used should preferably be 20-80 mol% of the polyol constituting the polyurethane polyol.

[0077] Polyether polyols can also be partially replaced by glycols such as ethylene glycol, 1,4-butanediol, neopentyl glycol, butyl ethyl pentyl glycol, glycerol, trimethylolpropane, neopentyl tertrol, or polyamines such as ethylenediamine, N-aminoethyl ethanolamine, isophorone diamine, and succinyl diamine, depending on the requirements.

[0078] The polyether polyol may be a difunctional polyether polyol, or it may be partially or entirely a polyether polyol with a number average molecular weight of 1000-5000 and having at least three hydroxyl groups per molecule. If a polyether polyol with a number average molecular weight of 1000-5000 and having at least three hydroxyl groups per molecule is used, the balance between adhesion and re-peelability is better. With the polyether polyol, if the number average molecular weight is less than 1000, there is a risk of increased reactivity and easy gelation. Furthermore, with the polyether polyol, if the number average molecular weight is greater than 5000, there is a risk of decreased reactivity and consequently, a decrease in the cohesive power of the polyurethane polyol itself. The number average molecular weight of the polyether polyol is preferably 2500-3500.

[0079] Any suitable organic polyisocyanate compound may be used. Examples of such organic polyisocyanate compounds include aromatic polyisocyanates, aliphatic polyisocyanates, aromatic aliphatic polyisocyanates, alicyclic polyisocyanates, etc.

[0080] Examples of aromatic polyisocyanates include: 1,3-phenylene diisocyanate, 4,4'-diphenylene diisocyanate, 1,4-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, toluene 2,4-diisocyanate, toluene 2,6-diisocyanate, 4,4'-toluidine diisocyanate, toluene 2,4,6-triisocyanate, benzene 1,3,5-triisocyanate, anisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4',4”-triphenylmethane triisocyanate, etc.

[0081] Aliphatic polyisocyanates include, for example: trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-endenylpropyl diisocyanate, 2,3-endenylbutyl diisocyanate, 1,3-endenylbutyl diisocyanate, dodecamethyl diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, etc.

[0082] Aromatic aliphatic polyisocyanates include, for example: ω,ω'-diisocyanate-1,3-dimethylbenzene, ω,ω'-diisocyanate-1,4-dimethylbenzene, ω,ω'-diisocyanate-1,4-diethylbenzene, 1,4-tetramethylenyl diisocyanate, 1,3-tetramethylenyl diisocyanate, etc.

[0083] 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'-methylene bis(cyclohexyl isocyanate), 1,4-bis(isocyanate methyl)cyclohexane, 1,4-bis(isocyanate methyl)cyclohexane, etc.

[0084] Organic polyisocyanate compounds may also be used with trimethylolpropane adducts, biuret formed by reaction with water, terpolymers having a triisocyanate ring, etc.

[0085] Any suitable catalyst can be used as a catalyst for obtaining polyurethane polyols. Examples of such catalysts include tertiary amine compounds and organometallic compounds.

[0086] Examples of tertiary amine compounds include triethylamine, triethylenediamine, and 1,8-diazabicyclo(5,4,0)-undecene-7 (DBU).

[0087] Organometallic compounds include, for example, tin compounds and non-tin compounds.

[0088] Examples of tin 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, tin 2-ethylhexanoate, etc.

[0089] Examples of non-tin compounds include: titanium compounds such as dibutyl titanium dichloride, tetrabutyl titanate, and titanium trichloride; lead compounds such as lead oleate, lead 2-ethylhexanoate, lead benzoate, and lead naphthenate; iron compounds such as iron 2-ethylhexanoate and iron acetone; 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.

[0090] When using a catalyst to obtain polyurethane polyols, in systems containing two polyols—polyester polyol and polyether polyol—the different reactivity can easily lead to gelation or turbidity of the reaction solution in a single catalyst system. Therefore, by using two catalysts to obtain polyurethane polyols, these problems can be solved by easily controlling the reaction rate and catalyst selectivity. Examples of the combination of the two catalysts include tertiary amine / organometallic, tin / non-tin, and tin / tin, with tin / tin being preferable, and a combination of dibutyltin dilaurate and tin 2-ethylhexanoate being more suitable. The mixing ratio, by weight, should preferably be less than 1 for tin 2-ethylhexanoate / dibutyltin dilaurate, preferably 0.2 to 0.6. A mixing ratio greater than 1 may lead to gelation due to the imbalance of catalyst activity.

[0091] When using a catalyst to obtain polyurethane polyol, the amount of catalyst used should be 0.01 to 1.0 by weight relative to the total amount of polyester polyol, polyether polyol and organic polyisocyanate compound.

[0092] When using a catalyst to obtain polyurethane polyols, the reaction temperature should preferably be below 100°C, and more preferably 85°C to 95°C. If the temperature reaches above 100°C, it may be difficult to control the reaction rate and cross-linking structure, and it may be difficult to obtain polyurethane polyols with the predetermined molecular weight.

[0093] To obtain polyurethane polyols, a catalyst may not be used. In this case, the reaction temperature should preferably be above 100°C, and more preferably above 110°C. Furthermore, to obtain polyurethane polyols without a catalyst, the reaction should be carried out for more than 3 hours.

[0094] Methods for obtaining polyurethane polyols include, for example: 1) feeding all the polyester polyol, polyether polyol, catalyst, and organic polyisocyanate into a flask; 2) feeding the polyester polyol, polyether polyol, and catalyst into a flask and adding the organic polyisocyanate dropwise. For obtaining polyurethane polyols, method 2) is preferable in terms of reaction control.

[0095] To obtain polyurethane polyols, any suitable solvent can be used. Examples of such solvents include methyl ethyl ketone, ethyl acetate, toluene, xylene, acetone, etc. Toluene is particularly preferred among these solvents.

[0096] The aforementioned substances may be used for polyfunctional isocyanate compounds.

[0097] The method for manufacturing a polyurethane composition obtained from a composition containing a carbamate prepolymer may be any suitable manufacturing method if it is a method of manufacturing a polyurethane resin composition using a "carbamate prepolymer" as a raw material.

[0098] (Acrylic adhesive) There are no particular restrictions on acrylic adhesives. Known or even conventional acrylic adhesives can be used. For example, acrylic adhesives containing acrylic polymers as the base polymer can be used because they are easy to control to have low tack and low viscosity.

[0099] The aforementioned acrylic polymers are polymers in which the constituent units of the polymer are derived from acrylic monomers (monomer components having (meth)acrylic groups in the molecule). The aforementioned acrylic polymers are preferably polymers containing, by weight, a maximum of constituent units derived from (meth)acrylates. Furthermore, acrylic polymers can be used alone or in combination of two or more. Also, in this specification, "(meth)acrylic acid" means "acrylic acid" and / or "methacrylic acid" (either or both of "acrylic acid" and "methacrylic acid"), and so on.

[0100] Examples of the above-mentioned (meth)acrylates include (meth)acrylates containing hydrocarbon groups. Examples of (meth)acrylates containing hydrocarbon groups include alkyl (meth)acrylates, cycloalkyl (meth)acrylates, and aryl (meth)acrylates. Examples of the above-mentioned alkyl (meth)acrylates include: methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, isobutyl acrylate, secondary butyl acrylate, tertiary butyl acrylate, pentyl acrylate, isopentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, nonyl acrylate, decyl acrylate, isodecanyl acrylate, undecyl acrylate, dodecyl acrylate (laurate), tridecyl acrylate, tetradecyl acrylate, octadecyl acrylate, eicosyl acrylate, etc. Examples of the above-mentioned cycloalkyl (meth)acrylates include: cyclopentyl acrylate and cyclohexyl acrylate. Examples of the above-mentioned aryl (meth)acrylates include: phenyl acrylate and benzyl acrylate.

[0101] The above-mentioned hydrocarbon-containing (meth)acrylates can be used alone or in combination of two or more. From the perspective of properly exhibiting the basic properties such as adhesion of the hydrocarbon-containing (meth)acrylates in the first adhesive layer, and easily controlling for low adhesion and low viscosity, the proportion of hydrocarbon-containing (meth)acrylates in the total monomer composition used to form the acrylic polymer should preferably be 40% by weight or more, and more preferably 60% by weight or more.

[0102] The aforementioned acrylic polymers may also include constituent units derived from other monomeric components that can copolymerize with the aforementioned hydrocarbon-containing alkyl (meth)acrylates, for the purpose of modifying cohesiveness, heat resistance, adhesion, and viscousness. Examples of such other monomeric components include: carboxyl-containing monomers, acid anhydride monomers, hydroxyl-containing monomers, glycidyl-containing monomers, sulfonic acid-containing monomers, phosphate-containing monomers, acrylamide, acrylonitrile, and other functionalized monomers, vinyl ester monomers, etc. Examples of carboxyl-containing monomers include acrylic acid, methacrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itconic acid, maleic acid, fumaric acid, crotonic acid, etc. Examples of acid anhydride monomers include maleic anhydride, itconic anhydride, etc. Examples of hydroxyl-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-hydroxylaurate (meth)acrylate, and methyl (4-hydroxymethylcyclohexyl)methacrylate. Examples of epoxypropyl (meth)acrylate monomers include: glycidyl (meth)acrylate and methyl epoxypropyl (meth)acrylate. Examples of sulfonic acid (SA) monomers include: styrene sulfonic acid, allyl sulfonic acid, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamide propanesulfonic acid, methyl methacrylate, and (meth)acryloxynaphthalene sulfonic acid. Examples of phosphate (P) monomers include: 2-hydroxyethylacrylamide phosphate. Examples of the aforementioned vinyl ester monomers include vinyl acetate, vinyl propionate, vinyl butyrate, trimethylvinyl acetate, cyclohexanecarboxylic acid vinyl ester, and vinyl benzoate. Other monomer components can be used alone or in combination of two or more. From the perspective of appropriately presenting the basic properties such as adhesion inherent in hydrocarbon-containing (meth)acrylates in the first adhesive layer, and easily controlling for low adhesion and low tack, the total percentage of the aforementioned other monomer components in the total monomer composition used to form the acrylic polymer should preferably be 60% by weight or less, and more preferably 40% by weight or less.

[0103] In order to form a crosslinked structure in its polymer backbone, the above-mentioned acrylic polymers may also contain constituent units derived from polyfunctional monomers that can copolymerize with monomer components that form acrylic polymers. Examples of such polyfunctional monomers include: hexanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, neopentyl tetraethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, neopentyl tetraethylene tri(meth)acrylate, dinepentyl tetraethylene hexa(meth)acrylate, epoxy methacrylates (e.g., polyoxypropylene (meth)acrylate), polyester (meth)acrylates, carbamate (meth)acrylates, etc., monomers having (meth)acrylic acid groups and other reactive functional groups within their molecules. The above-mentioned polyfunctional monomers may be used alone or in combination of two or more. From the perspective of properly presenting the basic properties such as adhesion of (meth)acrylates containing hydrocarbon groups in the first adhesive layer, so as to easily control low adhesion and low viscosity, the ratio of the above-mentioned multifunctional monomers in the total monomer composition used to form acrylic polymers should preferably be 40% by weight or less, and more preferably 30% by weight or less.

[0104] Acrylic polymers can be obtained by polymerizing one or more monomer components containing acrylic monomers. Examples of polymerization methods include solution polymerization, emulsion polymerization, bulk polymerization, and suspension polymerization.

[0105] The weight average molecular weight of acrylic polymers should preferably be above 100,000, and more preferably between 200,000 and 3,000,000. If the weight average molecular weight is above 100,000, there is a tendency for fewer low molecular weight substances in the adhesive layer, which can better suppress contamination of electronic components, etc.

[0106] The acrylic adhesive composition forming the first adhesive layer may also 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 weight average molecular weight of the acrylic polymer can be increased, thereby controlling for low tack and low viscosity. Examples of such crosslinking agents include polyisocyanate compounds, epoxy compounds, polyol compounds (polyphenolic compounds, etc.), acrylamide compounds, melamine compounds, etc., preferably isocyanate-based and / or epoxy-based crosslinking agents. When using a crosslinking agent, its amount relative to 100 parts by weight of the acrylic polymer should preferably be about 10 parts by weight or less, more preferably 0.1 to 10 parts by weight.

[0107] Isocyanate-based crosslinking agents include, for example, aliphatic isocyanates, alicyclic isocyanates, and aromatic isocyanates. Examples of aliphatic isocyanates include trimethylene diisocyanate, butyl diisocyanate, hexamethylene diisocyanate, and diisocyanate. Examples of alicyclic isocyanates include cyclopentyl diisocyanate, cyclohexyl diisocyanate, isoflavone diisocyanate, and 1,3-bis(isocyanatomethyl)cyclohexane. Examples of aromatic isocyanates include toluene 2,4-diisocyanate, 4,4'-diphenylmethane diisocyanate, and butyl diisocyanate. Furthermore, other examples of isocyanate-based crosslinking agents include the trimethylolpropane adduct of toluene diisocyanate (trade name "Coronate L", manufactured by Tosoh Corporation) or the isocyanate derivative of hexamethylene diisocyanate (trade name "Coronate HX", manufactured by Tosoh Corporation).

[0108] Examples of epoxy crosslinking agents (multifunctional epoxy compounds) include: N,N,N',N'-tetracyclooxypropyl metadiamine, dicyclooxypropyl aniline, 1,3-bis(N,N-dicyclooxypropylaminomethyl)cyclohexane, 1,6-hexanediol dicyclooxypropyl ether, neopentyl glycol dicyclooxypropyl ether, ethylene glycol dicyclooxypropyl ether, propylene glycol dicyclooxypropyl ether, polyethylene glycol dicyclooxypropyl ether, polypropylene glycol dicyclooxypropyl ether, sorbitol. Examples of epoxy resins include alcohol-based polyoxypropylene ethers, glycerol-based polyoxypropylene ethers, neopentyl terephthalate-based polyoxypropylene ethers, polyglycerol-based polyoxypropylene ethers, sorbitan-based polyoxypropylene ethers, trimethylolpropane-based polyoxypropylene ethers, diepoxypropyl adipate, diepoxypropyl phthalate, triepoxypropyl-tris(2-hydroxyethyl) triisocyanate, resorcinol diepoxypropyl ether, and bisphenol-S-diepoxypropyl ether. Epoxy resins with two or more epoxy groups within their molecules can also be cited. Commercially available epoxy crosslinking agents include, for example, "TETRAD C" manufactured by MITSUBISHI GAS CHEMICAL (stock).

[0109] The adhesive composition constituting the first adhesive layer preferably includes a light release agent. By including a light release agent, a WBL (Weak Boundary Layer) is formed on the surface of the first adhesive layer, which can be easily controlled to achieve low adhesion and low tack.

[0110] There are no particular limitations on the light stripping agent. Known light stripping agents can be used without restriction, such as polysiloxane stripping agents, fluorinated surfactants, aliphatic esters, etc. These can be used alone or in combination of two or more.

[0111] The above-mentioned polysiloxane-based release agent is not particularly limited, and examples include thermosetting polysiloxane-based release agents and ionizing radiation-curing polysiloxane-based release agents. Furthermore, the polysiloxane-based release agent can be any type, including solvent-free type (containing no solvent) and solvent type (dissolved or dispersed in an organic solvent). In addition, polysiloxane-based release agents can be used alone or in combination of two or more types.

[0112] The above-mentioned thermosetting polysiloxane is not particularly limited, but is preferably an organohydrogen polysiloxane or an organosiloxane having an aliphatic unsaturated group. Furthermore, the above-mentioned polysiloxane is preferably a thermoaddition-cured polysiloxane that is cross-linked and cured by a thermoaddition reaction.

[0113] The above-mentioned thermoaddition-curable polysiloxane release agent is not particularly limited, and the following release agents may be suitable examples: polysiloxanes (polysiloxanes containing Si-H groups) having hydrogen atoms (H) bonded to silicon atoms (Si) in their molecules, and polysiloxanes (Si-H-based reactive polysiloxanes) containing functional groups (Si-H-based reactive functional groups) that are reactive to Si-H bonds (covalent bonds between Si and H) in their molecules. Furthermore, this release agent is cured by an addition reaction between Si-H groups and Si-H-based reactive functional groups, followed by crosslinking.

[0114] In the above-mentioned polysiloxanes containing Si-H groups, the Si with H bonds can be either the Si in the main chain or the Si in the side chain. The above-mentioned polysiloxanes containing Si-H groups are preferably polysiloxanes containing two or more Si-H groups in their molecules. Examples of suitable polysiloxanes containing two or more Si-H groups include dimethylhydrosiloxane polymers such as poly(dimethylsiloxane-methylsiloxane).

[0115] Furthermore, the aforementioned Si-H-based reactive polysiloxanes are preferably polysiloxanes in which Si-H-based reactive functional groups or side chains containing such functional groups are bonded to the Si (e.g., Si at the end of the main chain, Si inside the main chain) forming the backbone of the siloxane polymer. More preferably, these are polysiloxanes in which the Si-H-based reactive functional groups are directly bonded to the Si in the main chain. In addition, the aforementioned Si-H-based reactive polysiloxanes are also preferably polysiloxanes containing two or more Si-H-based reactive functional groups in their molecule.

[0116] Examples of Si-H reactive functional groups in the above-mentioned Si-H based reactive polysiloxanes include vinyl, hexenyl, and other alkenyl groups. Furthermore, examples of silicon-based polymers forming the main chain portion in the above-mentioned Si-H based reactive polysiloxanes include polydimethylsiloxane, polydiethylsiloxane, polymethylethylsiloxane, and other polydialkylsiloxanes (the two alkyl groups may be the same or different); polyalkylarylsiloxanes; poly(dimethylsiloxanemethylsiloxane); and polymers formed by polymerization of multiple Si-containing monomers. Among these, polydimethylsiloxane is preferred as the silicon-based polymer forming the main chain portion.

[0117] In particular, the above-mentioned thermoaddition-curable polysiloxane release agent is preferably a thermoaddition-curable polysiloxane release agent containing polysiloxanes with two or more Si-H groups in the molecule and polysiloxanes with two or more Si-H reactive functional groups in the molecule.

[0118] Furthermore, the above-mentioned free radiation curing polysiloxane release agent is not particularly limited, and UV curing polysiloxane release agents that are cured by cross-linking reaction initiated by ultraviolet (UV) irradiation can be appropriate examples.

[0119] The above-mentioned UV-curable polysiloxane release agent is a release agent that is cured by chemical reactions such as cationic polymerization, free radical polymerization, free radical addition polymerization, and hydrosilaneization initiated by UV irradiation. The above-mentioned UV-curable polysiloxane release agent is particularly suitable for UV-curable polysiloxane release agents that are cured by cationic polymerization.

[0120] The cationic polymeric UV-curable polysiloxane release agent is not particularly limited, and release agents comprising epoxy-containing polysiloxanes are suitable examples. In these epoxy-containing polysiloxanes, at least two epoxy groups are each directly or separated by a divalent group (methylene, ethyl, etc., alkyl; vinyl oxide, propylene oxide, etc., alkoxy, etc.) bonded to the Si (e.g., Si at the end of the main chain, Si within the main chain) and / or Si contained in the side chains of the main chain (backbone) forming the polysiloxane polymer. The bonding state of these at least two epoxy groups to Si can be the same or different. That is, release agents comprising one or more polysiloxanes containing two or more epoxy-containing side chains are suitable examples. Examples of epoxy-containing side chains include glycidyl, glycidyloxy (glycidyloxy), 3,4-epoxycyclohexyl, 2,3-epoxycyclopentyl, etc. The epoxy-containing polysiloxane can be linear, branched, or a mixture thereof.

[0121] In particular, from the viewpoint that it is easy to control the first adhesive layer to have low tack and low viscosity, the double-sided adhesive tape for transfer of the present invention preferably contains a thermosetting polysiloxane release agent in the polysiloxane adhesive, and more preferably contains a thermoaddition reaction curing polysiloxane release agent.

[0122] When the first adhesive layer of the double-sided adhesive tape for transfer of the present invention contains a polysiloxane adhesive, the content of the polysiloxane release agent is not particularly limited, but is preferably 0.5 parts by weight or more and 100 parts by weight or less relative to 100 parts by weight of the polysiloxane polymer of the base polymer. If the content is 0.5 parts by weight or more, it is easy to obtain the effect of easily controlling the first adhesive layer to have low adhesion and low tack, and it is more preferably 1 part by weight or more, and more preferably 3 parts by weight or more. Furthermore, if the content is 100 parts by weight or less, it is easy to suppress the following undesirable situation, namely, the inability to obtain sufficient adhesion and difficulty in receiving electronic components, and it is more preferably 30 parts by weight or less, and more preferably 25 parts by weight or less.

[0123] By using the above-mentioned fluorine-based surfactant as a light stripping agent, the light stripping effect brought about by the low surface free energy of the fluorine site can be utilized.

[0124] The above-mentioned fluorinated surfactants are not particularly limited, and examples include: fluorinated oligomers, perfluorobutane sulfonates, carboxylates containing perfluoroalkyl groups, sulfonates containing hexafluoropentane trimer derivatives, carboxylates containing hexafluoropentane trimer derivatives, quaternary ammonium salts containing hexafluoropentane trimer derivatives, betaine containing hexafluoropentane trimer derivatives, and polyoxyethylene ethers containing hexafluoropentane trimer derivatives, etc., among which fluorinated oligomers are preferred. Furthermore, fluorinated surfactants can be used alone or in combination of two or more.

[0125] Specific examples of the above-mentioned fluorinated surfactants, such as commercially available products, include: trade names "MEGAFACE F-114", "MEGAFACE F-410" (all manufactured by DIC), trade names "Surflon S-211", "Surflon S-221", "Surflon S-231", "Surflon S-232", "Surflon S-233", "Surflon S-241", "Surflon S-242", "Surflon S-243", "Surflon S-420" (all manufactured by AGC SEIMI CHEMICAL), trade names "Ftergent 100", "Ftergent 100C", "Ftergent 110", "Ftergent 150", "Ftergent 150CH", "Ftergent Ftergent 300, Ftergent 310, Ftergent 320, Ftergent 400SW, Ftergent 251, Ftergent 212M, Ftergent 215M, Ftergent 250, Ftergent 209F, Ftergent 222F, Ftergent 245F, Ftergent 208G, Ftergent 218GL, Ftergent 240G, Ftergent 212P, Ftergent 220P, Ftergent 228P, Ftergent FTX-218, Ftergent DFX-18 (all manufactured by NEOS). These compounds can be used alone or in mixtures of two or more.

[0126] The weight-average molecular weight (Mw) of the above-mentioned fluorinated oligomers is preferably 3,500 or more, more preferably 5,000 or more, more preferably 10,000 or more, and especially preferably 20,000 or more. If the weight-average molecular weight of the above-mentioned fluorinated oligomers is 3,500 or more, it is easy to control it to have low adhesion and low viscosity. Furthermore, if the weight-average molecular weight is 20,000 or more, foaming can be suppressed when blending with adhesives (compositions), and the appearance after applying the adhesive is excellent, which is ideal. Also, the upper limit of the weight-average molecular weight (Mw) of the above-mentioned fluorinated oligomers is preferably 200,000, and more preferably 100,000 or less. By setting the upper limit to 200,000, the fluorinated oligomers can easily exist locally on the surface, and it becomes easier to exert a light peeling effect, which is ideal.

[0127] Furthermore, examples of the aforementioned fluorinated oligomers, such as commercially available products, include: trade names "MEGAFACE F-251", "MEGAFACE F-253", "MEGAFACE F-281", "MEGAFACE F-410", "MEGAFACE F-430", "MEGAFACE F-444", "MEGAFACE F-477", "MEGAFACE F-510", "MEGAFACE F-511", "MEGAFACE F-551", "MEGAFACE F-552", "MEGAFACE F-553", "MEGAFACE F-554", "MEGAFACE F-555", "MEGAFACE F-556", "MEGAFACE F-557", "MEGAFACE F-558", "MEGAFACE F-559", "MEGAFACE F-559", "MEGAFACE F-551", "MEGAFACE F-251", "MEGAFACE F-253 ... F-560, MEGAFACE F-561, MEGAFACE F-562, MEGAFACE F-563, MEGAFACE F-565, MEGAFACE F-568, MEGAFACE F-569, MEGAFACE F-570, MEGAFACE F-571, MEGAFACE F-572 (all under DIC), Surflon S-611, Surflon S-651, Surflon S-386 (all under AGC SEIMI CHEMICAL), Ftergent 610FM, Ftergent 710FL, Ftergent 710FM, Ftergent 710FS, Ftergent 730FL, Ftergent 730LM (the above are manufactured by NEOS, etc.). These compounds can be used alone or in combination of two or more.

[0128] When the first adhesive layer of the transfer double-sided adhesive tape of the present invention contains a fluorinated surfactant, the content of the fluorinated surfactant is not particularly limited, but is preferably 0.01 parts by weight or more and 5 parts by weight or less relative to 100 parts by weight of the polysiloxane polymer of the base polymer. If the content is 0.01 parts by weight or more, it is easy to obtain the effect of easily controlling the first adhesive layer to have low adhesion and low tack, and is preferably 0.05 parts by weight or more, and more preferably 0.1 parts by weight or more. Furthermore, if the content is 5 parts by weight or less, it is easy to suppress the following undesirable situation, namely, the inability to obtain sufficient adhesion and difficulty in receiving electronic components, and from the viewpoint of suppressing the reduction of transparency, it is preferably 3 parts by weight or less, and more preferably 2 parts by weight or less.

[0129] By including fatty acid esters in the adhesive composition constituting the first adhesive layer, it is expected that the first adhesive layer will have low adhesion, low viscosity, and wettability to electronic components.

[0130] Examples of the above-mentioned fatty acid esters include: polyoxyethylene bisphenol A laurate, butyl stearate, 2-ethylhexyl palmitate, 2-ethylhexyl stearate, glyceryl monododecanoate, hexadecyl 2-ethylhexanoate, isopropyl myristate, isopropyl palmitate, cholesterol isostearate, lauryl methacrylate, methyl coconut oil, methyl laurate, methyl oleate, methyl stearate, myristyl myristate, octyl dodecyl myristate, neopentyl tetraoleate, neopentyl tetrastearate, stearate, isotridecyl stearate, glyceryl triglyceride, butyl laurate, octyl oleate, and tridecyl isononanoate. Fatty acid esters can be used alone or in combination of two or more.

[0131] From the viewpoint of the low adhesion, low viscosity, wettability or contamination of the first adhesive layer to electronic components, the content of fatty acid esters contained in the above-mentioned carbamate adhesive composition, for example, relative to 100 parts by weight of polyol, 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.

[0132] When the adhesive composition constituting the first adhesive layer includes a light release agent, its content (total amount) is preferably 0.1 parts by weight or more, more preferably 1 part by weight or more, and more preferably 3 parts by weight or more, relative to 100 parts by weight of the base polymer, from the viewpoint of the low adhesion, low tack, wettability, or contamination of the first adhesive layer to electronic components. 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 more preferably 10 parts by weight or less.

[0133] The above-mentioned ultraviolet absorbers are not particularly limited, and examples include triazole-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, diphenyl ketone-based ultraviolet absorbers, oxydiphenyl ketone-based ultraviolet absorbers, salicylate-based ultraviolet absorbers, and cyanoacrylate-based ultraviolet absorbers. These can be used alone or in combination of two or more. Among these, from the viewpoint of high ultraviolet absorption capacity around 250 nm, benzotriazole-based ultraviolet absorbers or triazole-based ultraviolet absorbers are preferred.

[0134] Tris(hydroxyl)-based ultraviolet absorbers having two or fewer hydroxyl groups in one molecule, specifically including: 2,4-bis-[{4-(4-ethylhexyloxy)-4-hydroxy}-phenyl]-6-(4-methoxyphenyl)-1,3,5-tris(hydroxyl) (trade name "Tinosorb S", manufactured by BASF), 2,4-bis[2-hydroxy-4-butoxyphenyl]-6-(2,4-dibutoxyphenyl)-1,3,5-tris(hydroxyl) (trade name "TINUVIN") 460 (manufactured by BASF), 2-(4,6-bis(2,4-dimethylphenyl)-1,3,5-tris(2 ... The reaction product of 6-bis-(2,4-dimethylphenyl)-1,3,5-tris(2-ethylhexyl)-glycidyl ester (trade name "TINUVIN405", manufactured by BASF), 2-(4,6-diphenyl-1,3,5-tris(2-ethylhexyl)oxy]-phenol (trade name "TINUVIN1577", manufactured by BASF), and 2-(4,6-diphenyl-1,3,5-tris(2-ethylhexyl)ethoxy]-phenol (trade name "ADK") STAB LA46 (manufactured by ADEKA), 2-(2-hydroxy-4-[1-octyloxycarbonylethoxy]phenyl)-4,6-bis(4-phenylphenyl)-1,3,5-tris(TINUVIN479, manufactured by BASF), etc.

[0135] Furthermore, examples of benzotriazole-based ultraviolet 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 (trade name "TINUVIN 928", manufactured by BASF), 2-(2-hydroxy-5-tert-butylphenyl)-2H-benzotriazole (trade name "TINUVIN 928"). PS (manufactured by BASF), ester compounds of phenylpropionic acid and 3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxy (C7-9 side chain and straight-chain alkyl) (trade name "TINUVIN384-2", manufactured by BASF), 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (trade name "TINUVIN900", manufactured by BASF), 2-(2H-benzotriazol-2- 6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol (trade name "TINUVIN 928", manufactured by BASF), the reaction product of methyl-3-(3-(2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyphenyl)propionate / polyethylene glycol 300 (trade name "TINUVIN 1130", manufactured by BASF), and 2-(2H-benzotriazol-2-yl)-p-cresol (trade name "TINUVIN") P”, manufactured by BASF, 2-(2H-benzotriazol-2-yl)-4-6-bis(1-methyl-1-phenylethyl)phenol (trade name "TINUVIN234", manufactured by BASF), 2-[5-chloro(2H)-benzotriazol-2-yl]-4-methyl-6-(tributyl)phenol (trade name "TINUVIN326", manufactured by BASF), 2-(2H-benzotriazol-2-yl)-4,6-di-trimethylpentylphenol (trade name "TINUVIN328", manufactured by BASF), 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol (trade name "TINUVIN328", manufactured by BASF) The products include: "TINUVIN329" (manufactured by BASF), the reaction product of methyl 3-(3-(2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyphenyl)propionate and polyethylene glycol 300 (trade name "TINUVIN213" (manufactured by BASF), 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-cresol (trade name "TINUVIN571" (manufactured by BASF), and 2-[2-hydroxy-3-(3,4,5,6-tetrahydrophthalimide-methyl)-5-methylphenyl]benzotriazole (trade name "Sumisorb250" (manufactured by Sumitomo Chemical Co., Ltd.)).

[0136] Furthermore, examples of the above-mentioned diphenyl ketone-based ultraviolet absorbers (diphenyl ketone compounds) and oxydiphenyl ketone-based ultraviolet absorbers (oxydiphenyl ketone compounds) include: 2,4-dihydroxydiphenyl ketone, 2-hydroxy-4-methoxydiphenyl ketone, 2-hydroxy-4-methoxydiphenyl ketone-5-sulfonic acid (anhydrous and trihydrate), 2-hydroxy-4-octyloxydiphenyl ketone, 4-dodecyloxy-2-hydroxydiphenyl ketone, 4-benzylmethyloxy-2-hydroxydiphenyl ketone, 2,2',4,4'-tetrahydroxydiphenyl ketone, 2,2'-dihydroxy-4,4-dimethoxydiphenyl ketone, etc.

[0137] Furthermore, examples of the above-mentioned salicylate-based ultraviolet absorbers (salicylate-based compounds) include: phenyl-2-propenyloxybenzoate, phenyl-2-propenyloxy-3-methylbenzoate, phenyl-2-propenyloxy-4-methylbenzoate, phenyl-2-propenyloxy-5-methylbenzoate, phenyl-2-propenyloxy-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, 2,4-di-tri-butylphenyl-3,5-di-tri-butyl-4-hydroxybenzoate (trade name "TINUVIN120", manufactured by BASF), etc.

[0138] The above-mentioned cyanoacrylate-based ultraviolet absorbers (cyanoacrylate-based compounds) can be exemplified by alkyl-2-cyanoacrylate, cycloalkyl-2-cyanoacrylate, alkoxyalkyl-2-cyanoacrylate, alkenyl-2-cyanoacrylate, alkynyl-2-cyanoacrylate, etc.

[0139] The above-mentioned ultraviolet absorbers can be used alone or in combination of two or more.

[0140] The maximum absorption wavelength of the absorption spectrum of the above-mentioned ultraviolet absorber is preferably in the wavelength region of 200~400nm, and more preferably in the wavelength region of 240~380nm. Examples of such ultraviolet absorbers include the trade name "Tinuvin 384-2" (maximum absorption wavelength 345nm, manufactured by BASF).

[0141] The ultraviolet transmittance TUV1 of the first adhesive layer with a wavelength of 248 nm will vary depending on the thickness of the first adhesive layer, but should preferably be 75% or less (preferably 70% or less, more preferably 50% or less, with a lower limit of 5%). In addition, the ultraviolet transmittance can be measured, for example, using a spectrophotometer (product name "U-4100") (manufactured by Hitachi High-Tech Science Co.) to measure the transmittance when ultraviolet light with a wavelength of 248 nm is incident perpendicularly on the first adhesive layer.

[0142] Furthermore, the value of the ultraviolet transmittance TUV1 of the first adhesive layer with a wavelength of 248 nm divided by the thickness t1 of the first adhesive layer (TUV1 / t1) should preferably be 5.00 or less, more preferably 4.90 or less, more preferably 4.80 or less, with a lower limit of 0.50, more preferably 0.70, and more preferably 1.00.

[0143] The content of the ultraviolet absorber in the adhesive composition constituting the first adhesive layer will vary depending on the thickness of the first adhesive layer. However, for example, when the thickness is 15µm, the content is preferably 0.05 to 1.5 parts by weight, more preferably 0.07 to 1.2 parts by weight, and even more preferably 1.0 to 1.0 parts by weight relative to 100 parts by weight of the adhesive.

[0144] The adhesive composition constituting the first adhesive layer may also include an antioxidant. By including an antioxidant, the deterioration of the double-sided adhesive sheet for transfer printing of the present invention, such as discoloration, can be suppressed during storage, and the processability can be improved by making it easier to cut the double-sided adhesive sheet for transfer printing.

[0145] Examples of the antioxidants mentioned above 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, especially hindered phenolic antioxidants.

[0146] Specific examples of phenolic antioxidants include, for example, monocyclic phenolic compounds such as 2,6-di-tertiary butyl-p-cresol, 2,6-di-tertiary butyl-4-ethylphenol, 2,6-dicyclohexyl-4-cresol, 2,6-diisopropyl-4-ethylphenol, 2,6-di-tertiary pentyl-4-cresol, 2,6-di-tertiary octyl-4-n-propanol, 2,6-dicyclohexyl-4-n-octylphenol, 2-isopropyl-4-methyl-6-tertiary butylphenol, 2-tertiary butyl-4-ethyl-6-tertiary octylphenol, 2-isobutyl-4-ethyl-6-tertiary hexylphenol, 2-cyclohexyl-4-n-butyl-6-isopropylphenol, styrene-modified mixed cresols, DL-α-tocopherol, and stearic acid β- (3,5-Di-tertiary butyl-4-hydroxyphenyl)propionate, etc.; as dicyclic phenolic compounds, examples include 2,2'-methylenebis(4-methyl-6-tertiary butylphenol), 4,4'-butylenebis(3-methyl-6-tertiary butylphenol), 4,4'-thiobis(3-methyl-6-tertiary butylphenol), 2,2'-thiobis(4-methyl-6-tertiary butylphenol), 4,4'-methylenebis(2,6-di-tertiary butylphenol), 2,2'-methylenebis[6-(1- [Methylcyclohexyl)-p-cresol], 2,2'-ethylidene bis(4,6-di-tertiary-butyrophenol), 2,2'-butylidene bis(2-tertiary-butyl-4-cresol), 3,6-dioxinoctyl bis[3-(3-tertiary-butyl-4-hydroxy-5-methylphenyl)propionate], triethylene glycol bis[3-(3-tertiary-butyl-5-methyl-4-hydroxyphenyl)propionate], 1,6-hexanediol bis[3-(3,5-di-tertiary-butyl-4-hydroxyphenyl)propionate], 2,2 '-Thiodiethyl bis[3-(3,5-di-tertiary butyl-4-hydroxyphenyl)propionate], etc.; as tricyclic phenolic compounds, examples include 1,1,3-tris(2-methyl-4-hydroxy-5-tertiary butylphenyl)butane, 1,3,5-tris(2,6-dimethyl-3-hydroxy-4-tertiary butylbenzyl)triisocyanate, 1,3,5-tris((3,5-di-tertiary butyl-4-hydroxyphenyl)propoxyethyl]triisocyanate, and tris(4-tertiary butyl-2,6-dimethyl-3-hydroxy-4-tertiary butylbenzyl)propionate. Examples of tetracyclic phenolic compounds include dimethyl-3-hydroxybenzyl) triisocyanate, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tri-butyl-4-hydroxybenzyl)benzene, etc.; examples of tetracyclic phenolic compounds include tetramethyl-3-(3,5-di-tri-butyl-4-hydroxyphenyl)propionate, etc.; examples of phosphorus-containing phenolic compounds include bis(3,5-di-tri-butyl-4-hydroxybenzylphosphonate ethyl ester) calcium, bis(3,5-di-tri-butyl-4-hydroxybenzylphosphonate ethyl ester) nickel, etc.

[0147] The above-mentioned antioxidants can be used alone or in combination of two or more. From the viewpoint of inhibiting deterioration such as discoloration during storage and the processability of double-sided adhesive sheets for transfer printing, for example, relative to 100 parts by weight of the first adhesive composition, the content of the anti-deterioration agent contained in the adhesive composition should preferably be 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.

[0148] The adhesive composition constituting the first adhesive layer may contain any suitable other components without impairing the effects of the present invention. Examples of such other components include, for instance, tackifiers, inorganic fillers, organic fillers, metal powders, pigments, foils, softeners, plasticizers, conductive agents, surface lubricants, leveling agents, heat stabilizers, polymerization inhibitors, lubricants, solvents, etc.

[0149] <Second Adhesive Layer> In the double-sided adhesive sheet for transfer printing of the present invention, the second adhesive layer is an adhesive layer used to temporarily fix to the carrier substrate, and it is composed of a peelable adhesive layer. The above-mentioned second adhesive layer is composed of a peelable adhesive layer. This configuration allows the second adhesive layer to be peeled off from the carrier substrate without residue or other contamination, thereby improving reworkability. This configuration is preferred in this respect.

[0150] The second adhesive layer described above can be made into a peelable adhesive layer by adjusting the adhesiveness by the type or composition of the adhesive, the degree of cross-linking, etc., or by reducing the adhesiveness by physical stimulation such as heat, ultraviolet light, and electromagnetic waves.

[0151] There is no particular limitation on the adhesion of the second adhesive layer to the glass plate at 25°C when peeled off at 180°. From the viewpoint of being able to peel off from the carrier substrate without residue or other contamination, thus improving reworkability, it is preferable to be 5000mN / 25mm or less, more preferably 3000mN / 25mm or less, and even more preferably 1000mN / 25mm or less. Furthermore, from the viewpoint of the adhesion of the carrier substrate to the second adhesive layer, the adhesion of the second adhesive layer to the glass plate at 25°C when peeled off at 180° is preferably 1mN / 25mm or more, and more preferably 5mN / 25mm or more.

[0152] Compared to the 180° peel adhesion of the second adhesive layer to the glass plate at 25°C (hereinafter sometimes referred to as "P2a" in this specification), after holding the transfer double-sided adhesive sheet at 160°C for 5 minutes, the ratio (P2b / P2a) of the second adhesive layer to the glass plate at 25°C (hereinafter sometimes referred to as "P2b" in this specification) is not particularly limited, but is preferably 3 or less, and more preferably 2.5 or less. A P2b / P2a ratio of 3 or less ensures that when electronic components received by the transfer double-sided adhesive sheet of the present invention are heat-pressed onto a mounting substrate for mounting, the adhesion of the second adhesive layer to the carrier substrate is not increased, resulting in good peelability and excellent reworkability. This configuration is preferred in this respect.

[0153] The 180° peel adhesion of the second adhesive layer at 25°C can be measured in the same manner as that of the first adhesive layer.

[0154] The adhesion of the second adhesive layer can be adjusted by adjusting the type or composition of the adhesive, the degree of crosslinking, etc., or by mixing a light stripping agent or plasticizer to form a WBL (Weak Boundary Layer).

[0155] In the double-sided adhesive sheet for transfer printing of the present invention, the thickness of the second adhesive layer is not particularly limited, but is preferably 1µm or more, and more preferably 3µm or more. If the thickness is above a certain value, the second adhesive layer can be easily and stably fixed on the carrier substrate, which is ideal. Furthermore, the upper limit of the thickness of the second adhesive layer is not particularly limited, but is preferably 30µm, and more preferably 20µm. If the thickness is below a certain value, the second adhesive layer can be easily peeled off from the carrier substrate, thereby improving reworkability, which is also ideal.

[0156] In the double-sided adhesive sheet for transfer printing 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. If the haze is 10% or less, excellent transparency can be obtained. For example, after the double-sided adhesive sheet for transfer printing is attached to the carrier substrate, the pattern attached to the carrier substrate (e.g., a mark indicating the receiving position of an electronic component) can be seen, which is ideal. In addition, the haze can be measured, for example, by forming the second adhesive layer on the separator and letting it stand at normal temperature (23°C, 50%RH) for at least 24 hours, peeling off the separator and attaching it to a glass slide (e.g., with a total light transmittance of 91.8% and a haze of 0.4%) to make a sample, and then measuring it using a haze meter (product name "HM-150", manufactured by Murakami Color Technology Research Institute).

[0157] In the double-sided adhesive sheet for transfer printing of the present invention, the total light transmittance (according to JIS K7361-1) of the second adhesive layer in the visible light wavelength region is not particularly limited, but is preferably 85% or more, and more preferably 88% or more. If the total light transmittance is 85% or more, excellent transparency can be obtained. For example, after the double-sided adhesive sheet for transfer printing is attached to the carrier substrate, the pattern attached to the carrier substrate (e.g., a mark indicating the receiving position of an electronic component) can be seen, which is ideal. In addition, the above-mentioned total light transmittance can be measured, for example, by forming the second adhesive layer on the separator and letting it stand at normal temperature (23°C, 50%RH) for at least 24 hours, peeling off the separator and attaching it to a glass slide (e.g., with a total light transmittance of 91.8% and a haze of 0.4%) to make a sample, and then measuring it using a haze meter (product name "HM-150", manufactured by Murakami Color Technology Research Institute).

[0158] There is no particular limitation on the adhesive constituting the second adhesive layer described above. Examples include polysiloxane adhesives, carbamate adhesives, acrylic adhesives, rubber adhesives, polyester adhesives, polyamide adhesives, epoxy adhesives, vinyl alkyl ether adhesives, and fluorinated adhesives used in the first adhesive layer described above. Among these, from the viewpoint of being able to be peeled off from the carrier substrate without residue or other contamination, thus improving reworkability, polysiloxane adhesives, carbamate adhesives, and acrylic adhesives are preferable, carbamate adhesives and acrylic adhesives are more preferable, and acrylic adhesives are even more preferable.

[0159] The second adhesive layer in the double-sided adhesive sheet for transfer printing of the present invention may be an adhesive layer whose adhesion can be intentionally reduced by external action during the use of the double-sided adhesive sheet for transfer printing (adhesive layer with reduced adhesion), or an adhesive layer whose adhesion is hardly or not reduced at all by external action during the use of the double-sided adhesive sheet for transfer printing (adhesive layer with non-reduced adhesion). It can be appropriately selected according to the method or conditions of using the double-sided adhesive sheet for transfer printing of electronic components of the present invention.

[0160] When the second adhesive layer is an adhesive layer with reduced adhesion, it can be applied to exhibit a state of relatively high adhesion and a state of relatively low adhesion during the manufacturing or use of the double-sided adhesive sheet for transfer of the present invention. For example, in the step where the first adhesive layer receives electronic components during the use of the double-sided adhesive sheet for transfer of the present invention, the relatively high adhesion of the second adhesive layer can be used to suppress and prevent the double-sided adhesive sheet for transfer from detaching from the carrier substrate. On the other hand, during the subsequent peeling process of the double-sided adhesive sheet for transfer of the present invention from the carrier substrate, the reduced adhesion of the second adhesive layer can improve reworkability.

[0161] Examples of adhesives that form the adhesive layer with reduced adhesion include radiation-curing adhesives and heat-foaming adhesives. The adhesives that form the adhesive layer with reduced adhesion can be used alone or in combination of two or more.

[0162] The above-mentioned radiation-curing adhesives may be adhesives that are cured by irradiation with electron beams, ultraviolet rays, alpha rays, beta rays, gamma rays or X-rays, and adhesives that are cured by ultraviolet irradiation (ultraviolet-curing adhesives) are particularly suitable.

[0163] Examples of the above-mentioned radiation-curing adhesives include additive radiation-curing adhesives, which contain a base polymer such as an acrylic polymer and radiation-polymerizable monomers or oligomers with functional groups such as radiation-polymerizable carbon-carbon double bonds.

[0164] The base polymer may be the same acrylic polymer as the first adhesive layer. From the viewpoint of properly exhibiting the basic properties such as adhesion brought about by the hydrocarbon-containing (meth)acrylate in the second adhesive layer, and to easily control adhesion and peelability, the proportion of hydrocarbon-containing (meth)acrylate in the total monomer composition used to form the acrylic polymer should preferably be 40% by weight or more, and more preferably 60% by weight or more.

[0165] The aforementioned acrylic polymer may also contain hydroxyl-containing monomers. When the acrylic polymer in the second adhesive layer contains hydroxyl-containing monomers, adequate cohesive force can be easily obtained in the second adhesive layer. From the viewpoint of achieving adequate adhesion or cohesive force in the second adhesive layer, the ratio of hydroxyl-containing monomers in the aforementioned acrylic polymer is, for example, 0.1 to 30% by weight, preferably 0.5 to 20% by weight.

[0166] The aforementioned acrylic polymer may also contain carboxyl-containing monomers. When the acrylic polymer in the second adhesive layer contains carboxyl-containing monomers, adequate adhesion reliability can be easily obtained in the second adhesive layer. From the viewpoint of achieving adequate adhesion reliability in the second adhesive layer, the ratio of carboxyl-containing monomers in the aforementioned acrylic polymer is, for example, 0.1 to 30% by weight, preferably 0.5 to 20% by weight.

[0167] The above-mentioned acrylic polymer may also contain vinyl ester monomers. When the acrylic polymer in the second adhesive layer contains vinyl ester monomers, moderate cohesive force can be easily obtained in the second adhesive layer. From the viewpoint of achieving moderate cohesive force in the second adhesive layer, the ratio of vinyl ester monomers in the above-mentioned acrylic polymer is, for example, 0.1 to 60% by weight, preferably 0.5 to 50% by weight.

[0168] The acrylic adhesive composition forming the second adhesive layer may also 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 weight average molecular weight of the acrylic polymer can be increased, thereby controlling for low adhesion and peelability. Regarding the aforementioned crosslinking agent, when using, for example, polyisocyanate compounds, epoxy compounds, polyol compounds (polyphenolic compounds, etc.), acrylamide compounds, melamine compounds, etc., and preferably an isocyanate-based crosslinking agent and / or an epoxy-based crosslinking agent, the amount used should preferably be about 10 parts by weight or less per 100 parts by weight of the acrylic polymer, and more preferably 0.1 to 10 parts by weight.

[0169] A crosslinking accelerator may also be used in the acrylic adhesive composition forming the second adhesive layer. The type of crosslinking accelerator can be appropriately selected according to the type of crosslinking agent used. In addition, in this specification, a crosslinking accelerator refers to a catalyst that increases the rate of the crosslinking reaction carried out using a crosslinking agent. Examples of such crosslinking accelerators include tin (Sn) compounds such as dioctyltin dilaurate, dibutyltin dilaurate, dibutyltin diacetate, dibutyltin diacetone, tetrabutyltin tetrabutyltin, and trimethyltin hydroxide; amines such as N,N,N',N'-tetramethylhexanediamine or triethylamine; and imidazole compounds. Sn-containing compounds are preferred. The use of such crosslinking accelerators is particularly effective when using a hydroxyl-containing monomer as the above-mentioned submonomer and an isocyanate-based crosslinking agent as the crosslinking agent. The amount of crosslinking accelerator contained in the above adhesive composition relative to 100 parts by weight of the above acrylic polymer can be set to, for example, about 0.001 to 0.5 parts by weight (preferably about 0.001 to 0.1 parts by weight).

[0170] Examples of the above-mentioned radiation-polymerizable monomer components include: carbamate (meth)acrylate, trimethylolpropane tri(meth)acrylate, neopentyl tert-methacrylate, neopentyl tert-methacrylate, dinepentyl tert-hydroxypent(meth)acrylate, dinepentyl tert-hexa(meth)acrylate, 1,4-butanediol di(meth)acrylate, etc. Examples of the above-mentioned radiation-polymerizable oligomer components include various oligomers such as carbamate-based, polyether-based, polyester-based, polycarbonate-based, and polybutadiene-based oligomers, preferably with a molecular weight of about 100 to 30,000. The content of the above-mentioned radiation-curing monomer components and oligomer components in the radiation-curing adhesive forming the second adhesive layer, relative to 100 parts by weight of the above-mentioned base polymer, is, for example, 5 to 500 parts by weight, preferably about 40 to 150 parts by weight. Furthermore, additive-type radiation-curing adhesives may also use, for example, those disclosed in Japanese Patent Application Publication No. 60-196956.

[0171] Examples of the aforementioned radiation-curing adhesives include intrinsic radiation-curing adhesives, which contain functional groups such as radiation-polymerizable carbon-carbon double bonds in the polymer side chains, polymer backbone, or at the ends of the polymer backbone. When such intrinsic radiation-curing adhesives are used, there is a tendency to suppress the movement of low molecular weight components within the formed second adhesive layer, thus preventing unintentional, time-dependent changes in adhesive properties.

[0172] The base polymer contained in the above-mentioned intrinsic radiation-curing adhesive is preferably an acrylic polymer. A method for introducing radiation-polymerizable carbon-carbon double bonds into the acrylic polymer can be, for example, the following: after obtaining an acrylic polymer by polymerizing (copolymerizing) a raw material monomer containing a monomer component having a first functional group, a compound having a second functional group capable of reacting with the aforementioned first functional group and radiation-polymerizable carbon-carbon double bonds is subjected to a condensation reaction or addition reaction on the acrylic polymer while maintaining the radiation-polymerizability of the carbon-carbon double bonds.

[0173] Examples of combinations of the first functional group and the second functional group include carboxyl and epoxy group, epoxy group and carboxyl group, carboxyl and acridine group, acridine group and carboxyl group, hydroxyl and isocyanate group, and isocyanate group and hydroxyl group. From the viewpoint of ease of reaction tracking, the combination of hydroxyl and isocyanate group and the combination of isocyanate group and hydroxyl group are preferred. Among these, from the viewpoint of the high technical difficulty of producing polymers with highly reactive isocyanate groups, and on the other hand, the ease of producing acrylic polymers with hydroxyl groups, the combination of the first functional group being hydroxyl and the second functional group being isocyanate group is preferred. Compounds containing isocyanate groups and radiatively polymerizable carbon-carbon double bonds, i.e., isocyanate compounds containing radiatively polymerizable unsaturated functional groups, include, for example, methacrylic acid isocyanate, 2-methacrylic acidoxyethyl isocyanate, and m-isopropenyl-α,α-dimethylbenzyl isocyanate. Furthermore, acrylic polymers containing hydroxyl groups may include those derived from the aforementioned hydroxyl-containing monomers, or from ether compounds such as 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, and diethylene glycol monovinyl ether.

[0174] The above-mentioned radiation-curing adhesives preferably contain a photopolymerization initiator. Examples of such photopolymerization initiators include: α-keto alcohol compounds, acetophenone compounds, benzoin ether compounds, ketal compounds, aromatic sulfonyl chloride compounds, photoactive oxime compounds, diphenyl ketone compounds, 9-oxosulfur compounds, camphorquinone, halogenated ketones, acetophosphine oxide, acetophosphonates, etc. Examples of such α-keto alcohol compounds include 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)one, α-hydroxy-α,α'-dimethylacetophenone, 2-methyl-2-hydroxyacetophenone, 1-hydroxycyclohexylphenyl ketone, etc. Examples of the aforementioned acetophenone compounds include methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, and 2-methyl-1-[4-(methylthio)-phenyl]-2-morphofolin-1-one. Examples of the aforementioned benzoin ether compounds include benzoin ethyl ether, benzoin isopropyl ether, and anisolein methyl ether. Examples of the aforementioned ketal compounds include benzyl dimethyl ketal. Examples of the aforementioned aromatic sulfonyl chloride compounds include 2-naphthalenesulfonyl chloride. Examples of the aforementioned photoactive oxime compounds include 1-benzene-1,2-propanedione-2-(O-ethoxycarbonyl)oxime. Examples of the aforementioned diphenylketone compounds include diphenylketone, benzoylbenzoic acid, and 3,3'-dimethyl-4-methoxydiphenylketone. Examples of the aforementioned 9-oxosulfur compounds include: 9-oxosulfur, 2-chloro-9-oxosulfur, 2-methyl-9-oxosulfur, 2,4-dimethyl-9-oxosulfur, isopropyl-9-oxosulfur, 2,4-dichloro-9-oxosulfur, 2,4-diethyl-9-oxosulfur, and 2,4-diisopropyl-9-oxosulfur. The content of the photopolymerization initiator in the radiation-curing adhesive is, for example, 0.05 to 20 parts by weight relative to 100 parts by weight of the base polymer.

[0175] The above-mentioned heat-expanding adhesive is an adhesive containing components that foam or expand upon heating (foaming agent, thermally expandable microspheres, etc.). Examples of the above-mentioned foaming agents include various inorganic or organic foaming agents. Examples of the above-mentioned inorganic foaming agents include, for example, ammonium carbonate, ammonium bicarbonate, sodium bicarbonate, ammonium nitrite, sodium borohydride, azides, etc. Examples of organic foaming agents include: chlorofluoromethane, dichlorofluoromethane, and other chlorofluoroalkanes; azo compounds such as azobisisobutyronitrile, azodimethylamine, and barium azodicarboxylate; hydrazine compounds such as p-toluylene sulfonyl hydrazine, diphenylene-3,3'-disulfonyl hydrazine, 4,4'-oxybis(benzenesulfonyl hydrazine), and allylbis(sulfonyl hydrazine); semicarbazine compounds such as p-toluylene sulfonyl semicarbazide and 4,4'-oxybis(benzenesulfonyl semicarbazine); triazole compounds such as 5-morphofolinyl-1,2,3,4-thiatriazole; and N-nitroso compounds such as N,N'-dinitrospentamethylenetetramine and N,N'-dimethyl-N,N'-dinitrosophenyldimethylamine. Examples of the aforementioned thermally expandable microspheres include microspheres composed of a substance that easily expands upon heating and vaporizes within its shell. Examples of such substances include isobutane, propane, and pentane. Thermally expandable microspheres can be manufactured by sealing this easily expanded, vaporized substance within a shell-forming material using methods such as condensation or interfacial polymerization. The shell-forming material can be a substance exhibiting thermal melting properties or a substance that can rupture due to the thermal expansion of the sealed material. Examples of such substances include vinylidene-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinyl chloride, and polyurethane.

[0176] The aforementioned non-adhesive-reducing adhesive layer can be exemplified by a pressure-sensitive adhesive layer. Furthermore, the pressure-sensitive adhesive layer includes an adhesive layer of the following form: an adhesive layer formed from a radiation-curing adhesive, as described above for a non-adhesive-reducing adhesive layer, is irradiated with radiation to harden it and thus acquire a certain adhesive strength. The adhesive forming the non-adhesive-reducing adhesive layer can be used alone or in combination of two or more types. Also, the second adhesive layer can be entirely a non-adhesive-reducing adhesive layer, or it can be partially a non-adhesive-reducing adhesive layer. For example, when the second adhesive layer has a monolayer structure, the second adhesive layer can be entirely a non-adhesive-reducing adhesive layer, or a specific portion of the second adhesive layer can be a non-adhesive-reducing adhesive layer while other portions are non-adhesive-reducing adhesive layers. Furthermore, when the second adhesive layer has a laminated structure, all adhesive layers in the laminated structure can be non-adhesive strength type adhesive layers, or some adhesive layers in the laminated structure can be non-adhesive strength type adhesive layers.

[0177] An adhesive layer formed by irradiating radiation with radiation to harden it (a radiation-cured adhesive layer that has undergone radiation irradiation) can still exhibit the adhesiveness of its contained polymer components even if the adhesive force is reduced due to radiation irradiation, thus achieving the minimum adhesive force required for the double-sided adhesive sheet for transfer printing of the present invention. When using a radiation-cured adhesive layer that has undergone radiation irradiation, in the surface extension direction of the second adhesive layer, the second adhesive layer can be entirely a radiation-cured adhesive layer that has undergone radiation irradiation, or a portion of the second adhesive layer can be a radiation-cured adhesive layer that has undergone radiation irradiation and the other portion can be a radiation-cured adhesive layer that has not undergone radiation irradiation. Furthermore, in this specification, "radiation-curing adhesive layer" means an adhesive layer formed by a radiation-curing adhesive, which includes both a radiation-curing adhesive layer that has not been irradiated with radiation and a radiation-curing adhesive layer that has been cured by irradiation with radiation.

[0178] The adhesive used to form the pressure-sensitive adhesive layer described above can be a known or even conventional pressure-sensitive adhesive, and an acrylic adhesive with an acrylic polymer as its base polymer is suitable. When the second adhesive layer contains an acrylic polymer as a pressure-sensitive adhesive, the acrylic polymer should preferably be a polymer containing (meth)acrylate-derived units as the most abundant constituent units by weight. The acrylic polymer described above can be, for example, the acrylic polymer described in the above-mentioned additive radiation-curing adhesives.

[0179] <Substrate> The substrate in the double-sided adhesive sheet for transfer printing of the present invention is an element that functions as a support in the first adhesive layer or the second adhesive layer. Examples of substrates include plastic substrates (especially plastic films). The substrate can be a single layer or a laminate of the same or different substrates.

[0180] The resins constituting the above-mentioned plastic substrates may include, for example: low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, ultra-low-density polyethylene, random copolymer polypropylene, block copolymer polypropylene, homopolymer polypropylene, polybutene, polymethylpentene, ethylene-vinyl acetate copolymer (EVA), ionomers, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid (random, alternating) copolymer, ethylene-butene copolymer, ethylene-hexene copolymer, and other polyolefin resins; polyurethane; polyethylene terephthalate (PET), polyethylene naphthalate (PET), polybutylene terephthalate (PBT), and other polyesters; polycarbonate; polyimide; polyetheretherketone; polyetherimide; arylamine, fully aromatic polyamine, and other polyamides; polyphenylene ether; fluoropolymers; polyvinyl chloride; polyvinyl chloride; cellulose resins; polysiloxane resins, etc. When electronic components received by the double-sided adhesive sheet of this invention are heat-pressed (e.g., at 150°C) and transferred onto a mounting substrate for mounting, they exhibit good heat resistance, preventing expansion or contraction due to heat, and can be precisely mounted. From this perspective, the substrate should preferably contain heat-resistant resins such as polyimide (PI), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyamide (PA), and polyetheretherketone (PEEK) as main components, and polyimide is preferred. Furthermore, the main component of the substrate refers to the component that accounts for the largest weight percentage in the composition. The above-mentioned resins can be used alone or in combination of two or more. When the second adhesive layer is a radiation-curing adhesive layer as described above, the substrate should preferably have radiation transmittance.

[0181] When the substrate is a plastic film, the plastic film may be non-oriented or oriented in at least one direction (uniaxial direction, biaxial direction, etc.), but non-oriented films are less likely to exhibit heat shrinkage.

[0182] To improve adhesion and retention with the adhesive layer, the surfaces of the first and / or second adhesive layers of the substrate may undergo physical treatments such as corona discharge treatment, plasma treatment, sanding treatment, ozone exposure treatment, flame exposure treatment, high voltage electric shock exposure treatment, and ionized radiation treatment; chemical treatments such as chromic acid treatment; coating agents (primers); and easy-adhesion treatments using polysiloxane primers. Furthermore, to impart antistatic properties, in addition to providing a conductive vapor-deposited layer containing metals, alloys, or such oxides on the substrate surface, a conductive polymer such as PEDOT-PSS may be coated. The surface treatment to improve adhesion should preferably be applied to the entire surface of the adhesive layer side of the substrate.

[0183] From the viewpoint of ensuring the strength of the substrate to function as a support for the double-sided adhesive sheet for transfer printing of the present invention, the thickness of the substrate is preferably 5µm or more, more preferably 10µm or more, more preferably 15µm or more, and especially preferably 20µm or more. Furthermore, from the viewpoint of achieving appropriate flexibility in the double-sided adhesive sheet for transfer printing of the present invention, the thickness of the substrate is preferably 200µm or less, more preferably 180µm or less, and even more preferably 150µm or less.

[0184] In the double-sided adhesive sheet for transfer printing 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. If the haze is 10% or less, excellent transparency can be obtained. For example, after the double-sided adhesive sheet for transfer printing is attached to the carrier substrate, the pattern attached to the carrier substrate (such as a mark indicating the receiving position of an electronic component) can be seen, which is ideal. In addition, the above-mentioned haze can be measured using a haze meter (product name "HM-150", manufactured by Murakami Color Technology Research Institute Co., Ltd.).

[0185] In the double-sided adhesive sheet for transfer printing of the present invention, the total light transmittance of the substrate in the visible light wavelength region (according to JIS K7361-1) is not particularly limited, but is preferably 85% or more, and more preferably 88% or more. If the total light transmittance is 85% or more, excellent transparency can be obtained. For example, after the double-sided adhesive sheet for transfer printing is attached to the carrier substrate, the pattern attached to the carrier substrate (such as a mark indicating the receiving position of an electronic component) can be seen, which is ideal. In addition, the above-mentioned total light transmittance can be measured using a haze meter (product name "HM-150", manufactured by Murakami Color Technology Research Institute Co., Ltd.).

[0186] <Separator> The adhesive layer surface (adhesive surface of the first adhesive layer and / or the second adhesive layer) of the double-sided adhesive sheet for transfer printing of the present invention can also be protected by a release liner (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. FIG2 is a cross-sectional schematic diagram showing one embodiment of the double-sided adhesive sheet for transfer printing of the present invention, where 1 represents the double-sided adhesive sheet for transfer printing, 10 represents the substrate, 11 represents the first adhesive layer, 12 represents the second adhesive layer, and 110 and 120 represent separators. In addition, the separator is not required.

[0187] The above-mentioned separator can utilize conventional release paper, etc. Specifically, in addition to a substrate having a release treatment layer formed by a release treatment agent on at least one surface, a low-adhesion substrate made of fluoropolymers (e.g., polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, chlorofluoroethylene-vinylidene fluoride copolymer, etc.) or a low-adhesion substrate made of non-polar polymers (e.g., polyethylene, polypropylene and other olefin resins, etc.) can also be used.

[0188] The above-mentioned separator may, for example, be a separator in which at least one side of the separator substrate has a peeling layer formed. Examples of the separator substrate include: polyester film (polyethylene terephthalate film, etc.), olefin resin film (polyethylene film, polypropylene film, etc.), polyvinyl chloride film, polyimide film, polyamide film (nylon film), rayon film and other plastic substrate films (synthetic resin films) or paper (wood paper, Japanese paper, kraft paper, glassine paper, synthetic paper, coated paper, etc.), and also materials obtained by laminating or co-extruding such composites (2 to 3-layer composites).

[0189] The release agent constituting the above-mentioned release treatment layer is not particularly limited, and for example, polysiloxane-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. In addition, the first adhesive layer is composed of a low-tack adhesive layer, so a substrate that has not been treated with the release agent can also be used as a release element.

[0190] In order to prevent adverse effects on electronic components, the above-mentioned separator may also have an antistatic layer formed on at least one side of the substrate of the separator. The antistatic layer may be formed on one side of the separator (the peeled surface or the untreated surface), or it may be formed on both sides of the separator (the peeled surface and the untreated surface).

[0191] Antistatic agents contained in antistatic resins may include: cationic antistatic agents with cationic functional groups such as quaternary ammonium salts, pyridinium salts, primary, secondary, and tertiary amine groups; anionic antistatic agents with anionic functional groups such as sulfonate or sulfate salts, phosphonates, and phosphate salts; amphoteric antistatic agents such as alkyl betaine and its derivatives, imidazoline and its derivatives, and alanine and its derivatives; nonionic antistatic agents such as amino alcohols and their derivatives, glycerol and its derivatives, and polyethylene glycol and its derivatives; and ionically conductive polymers obtained by polymerization or copolymerization of monomers having the above-mentioned cationic, anionic, and amphoteric ionically conductive groups. These compounds may be used alone or in combination of two or more.

[0192] The thickness of the separator is not particularly limited and can be appropriately selected from the range of 5 to 100µm.

[0193] The manufacturing method of the double-sided adhesive sheet for transfer printing of the present invention may vary depending on the composition of the adhesive composition, etc., and is not particularly limited. Known forming methods can be used, but the following methods (1) to (4) are examples. (1) A method for manufacturing an adhesive sheet by coating (applying) the above-mentioned adhesive composition onto a substrate to form a composition layer, and hardening the composition layer (e.g., by heat curing or irradiation with active energy lines such as ultraviolet light) to form an adhesive layer. (2) A method for manufacturing an adhesive sheet by coating (applying) the above-mentioned adhesive composition onto a separator to form a composition layer, and hardening the composition layer (e.g., by heat curing or irradiation with active energy lines such as ultraviolet light) to form an adhesive layer, and then transferring the adhesive layer onto a substrate. (3) A method for manufacturing an adhesive sheet by coating (applying) the above-mentioned adhesive composition onto a substrate and drying it to form an adhesive layer. (4) A method for manufacturing an adhesive sheet by coating (applying) the above-mentioned adhesive composition onto a separator and drying it to form an adhesive layer, and then transferring the adhesive layer onto a substrate.

[0194] Among the hardening methods in (1) to (4) above, the method of thermal hardening is preferable in terms of excellent productivity and the ability to form a homogeneous and smooth adhesive layer.

[0195] The method of applying (coating) the above-mentioned adhesive composition to the predetermined surface can be any known coating method, without particular limitation, such as: roller coating, contact roller coating, gravure coating, reverse coating, roller brush, spray coating, dip roller coating, bar coating, doctor blade coating, air knife coating, curtain coating, lip coating, extrusion coating using a die coating machine, etc.

[0196] The thickness (total thickness) of the double-sided adhesive sheet for transfer printing of the present invention is not particularly limited, but it is preferably 10µm or more, and more preferably 15µm or more. If the thickness is above a certain level, the first adhesive layer can easily and accurately receive electronic components, which is ideal. Furthermore, the upper limit of the thickness (total thickness) of the double-sided adhesive sheet for transfer printing of the present invention is not particularly limited, but it is preferably 500µm, and more preferably 300µm. If the thickness is below a certain level, it is easy and accurate to transfer electronic components onto the mounting substrate, which is ideal. In addition, the thickness of the double-sided adhesive sheet for transfer printing of the present invention is set to exclude the thickness of the separating element.

[0197] The haze of the double-sided adhesive sheet for transfer printing of the present invention (according to JIS K7136) is not particularly limited, but is preferably 10% or less, and more preferably 5.0% or less. If the haze is 10% or less, excellent transparency can be obtained. For example, after the double-sided adhesive sheet for transfer printing is attached to the carrier substrate, the pattern attached to the carrier substrate (e.g., a mark indicating the receiving position of an electronic component) can be seen, which is ideal. In addition, the haze can be measured, for example, after the double-sided adhesive sheet for transfer printing is left to stand at normal temperature (23°C, 50%RH) for at least 24 hours, if there is a separator, the separator is peeled off and attached to a glass slide (e.g., with a total light transmittance of 91.8% and a haze of 0.4%) to make a sample, and then measured using a haze meter (product name "HM-150", manufactured by Murakami Color Technology Research Institute).

[0198] The total light transmittance (according to JIS K7361-1) of the double-sided adhesive sheet for transfer in the visible light wavelength region is not particularly limited, but is preferably 85% or higher, and more preferably 88% or higher. If the total light transmittance is 85% or higher, excellent transparency can be obtained. For example, after the double-sided adhesive sheet for transfer is attached to the carrier substrate, the pattern attached to the carrier substrate (e.g., a mark indicating the receiving position of an electronic component) can be seen, which is ideal. In addition, the above-mentioned total light transmittance can be measured, for example, by leaving the double-sided adhesive sheet for transfer at normal temperature (23°C, 50%RH) for at least 24 hours, and if there is a separator, peeling off the separator and attaching it to a glass slide (e.g., with a total light transmittance of 91.8% and a haze of 0.4%) to make a sample, and then measuring it using a haze meter (product name "HM-150", manufactured by Murakami Color Technology Research Institute).

[0199] The double-sided adhesive transfer sheet of the present invention is suitable for mounting methods of mounting electronic components onto a mounting substrate. The mounting method for mounting electronic components using the double-sided adhesive transfer sheet of the present invention onto a mounting substrate preferably includes the following steps: Step 1: Receiving a cut electronic component in the first adhesive layer of the double-sided adhesive transfer sheet; Step 2: Transferring the electronic component received in the first adhesive layer onto the mounting substrate.

[0200] Figure 3 is a cross-sectional schematic diagram, which shows one embodiment of the first step in the mounting method of mounting electronic components using the double-sided adhesive sheet for transfer of the present invention onto a mounting substrate.

[0201] In Figure 3(a), the double-sided adhesive sheet 1 for transfer is attached to the carrier substrate 22 with the adhesive side of the second adhesive layer 12. Marking patterns for mounting electronic components may also be attached to the surface of the carrier substrate 22 where it is attached to the second adhesive layer 12. The double-sided adhesive sheet 1 for transfer has high transparency, so the marking patterns attached to the carrier substrate 22 are visible.

[0202] A plurality of electronic components 21, which are cut and monolithically processed, are disposed on the upper part of the adhesive surface of the first adhesive layer 11 of the double-sided adhesive sheet 1 for transfer. The plurality of electronic components 21 are arranged with their surfaces facing the adhesive surface of the first adhesive layer 11 and spaced apart, in a state of being attached to the cutting tape 20.

[0203] In Figure 3(b), the pin member 23 pushes the electronic component 21 from the side of the cutting tape 20 where the electronic component 21 is not attached, bringing the electronic component 21 close to the adhesive surface of the first adhesive layer 11, so that the adhesive surface of the first adhesive layer 11 receives it. Receiving can be done by contacting the electronic component 21 to receive it, or it can be done in a non-contact manner. In a non-contact manner, the electronic component 21 is pushed until it peels off from the cutting tape 20, causing it to fall onto the adhesive surface. When receiving by contacting the electronic component 21, because the adhesive surface of the first adhesive layer 11 has low adhesion, the stress generated when the electronic component 21 is received is weaker, thereby suppressing damage to the electronic component 21. In a non-contact manner, because the adhesive surface of the first adhesive layer 11 has low adhesion, the falling electronic component 21 can be accurately caught. In addition, the pin component 23 can be replaced by irradiation with ultraviolet rays, laser rays, or other radiation to peel the electronic component 21 off the cutting tape 20.

[0204] The electronic components 21 can be received individually or in batches. Figure 3(c) is a cross-sectional schematic diagram showing the shape of all electronic components 21 receiving the cutting tape 20 on the adhesive surface of the first adhesive layer 11 of the transfer double-sided adhesive sheet 1.

[0205] Figure 4 is a cross-sectional schematic diagram, which shows the second step of the mounting method for mounting electronic components using the double-sided adhesive sheet for transfer of the present invention onto a mounting substrate.

[0206] As shown in FIG4(a), electronic components 21 are arranged on the adhesive surface of the first adhesive layer 11 of the transfer double-sided adhesive sheet 1, facing the circuit surface 31 (circuit pattern omitted) of the mounting substrate 30 and spaced apart. Next, as shown in FIG4(b), the circuit surface 31 of the mounting substrate 30 is brought close to the electronic components 21 arranged on the adhesive surface of the first adhesive layer 11 of the transfer double-sided adhesive sheet 1, so that the electronic components 21 contact the circuit surface 31 of the mounting substrate 30.

[0207] The transfer of electronic component 21 to the circuit surface 31 of mounting substrate 30 can also be performed by heat pressing (e.g., 150°C for 1 minute). The substrate 10, the first adhesive layer 11 and / or the second adhesive layer 12 constituting the double-sided adhesive sheet 1 for transfer have excellent heat resistance, so they are not easily expanded or contracted due to heat pressing, and the adhesive force is not easily changed. Therefore, electronic component 21 can be accurately transferred to the circuit surface 31 of mounting substrate 30.

[0208] Next, as shown in FIG4(c), by spacing the transfer double-sided adhesive sheet 1 from the mounting substrate 30, the electronic component 21 is peeled off from the first adhesive layer 11 and transferred onto the circuit surface 31 of the mounting substrate 30. The first adhesive layer 11 is composed of a low-adhesion adhesive layer, so the electronic component 21 can be easily peeled off and efficiently mounted on the mounting substrate 30 without damaging the electronic component 21.

[0209] The double-sided adhesive sheet 1 for transfer printing shown in FIG4(c) after the electronic component 21 is mounted on the mounting substrate 30 can also be peeled off from the carrier substrate 22 (figure omitted). The second adhesive layer 12 is composed of a peelable adhesive layer, so it can be peeled off without residue, thus exhibiting excellent reworkability, and the carrier substrate 22 can be easily reused.

[0210] There are no particular limitations on the electronic components to be mounted on the mounting substrate, and they are suitable for use on fine and thin semiconductor wafers or LED wafers.

[0211] Examples The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0212] <Example 1> 100 parts by weight of polysiloxane adhesive (addition reaction type polysiloxane 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.), 5 parts by weight of polysiloxane release agent 1 (addition reaction type polysiloxane release agent with dimethyl polysiloxane as the main component, trade name "KS-776A", manufactured by Shin-Etsu Chemical Co., Ltd.), and 0.2 parts by weight of ultraviolet absorber (trade name "Tinuvin384-2", maximum absorption wavelength 345nm, manufactured by BASF), and diluted with toluene to make the total solid content 25% by weight, and mixed with a disperser to prepare a polysiloxane adhesive composition (1).

[0213] A polysiloxane adhesive composition (1) was applied to the polysiloxane-primed surface of a substrate film (a polyester film with one side treated with a polysiloxane primer, 75µm thick, trade name "DIAFOIL MRF#75", manufactured by Mitsubishi Resin Co., Ltd.) to achieve a dry adhesive thickness of 15µm. The film was then cured and dried at a drying temperature of 120°C for 5 minutes. Following the above method, a film having a polysiloxane adhesive layer on the polysiloxane primer layer of the substrate film was obtained.

[0214] In addition, a release element (1) (a polyethylene terephthalate film without peeling treatment, 25µm thick, trade name "Lumirror S10#25", manufactured by Toyobo) is attached to the adhesive surface of the polysiloxane adhesive film to protect the polysiloxane adhesive layer, thereby obtaining a laminate (1) having a laminate structure of [release element (1) layer] / [polysiloxane adhesive (1) layer] / [substrate film layer].

[0215] Next, in a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen inlet pipe, and a cooler, 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 Toa Synthetic Co., Ltd.), 0.02 parts by weight of 2,2'-azobisisobutyronitrile (manufactured by Fuji Film & Water Purification Co., Ltd.) as a polymerization initiator, and 180 parts by weight of ethyl acetate were introduced. Nitrogen gas was introduced while stirring slowly, and the liquid temperature in the flask was maintained at around 65°C for 6 hours to carry out the polymerization reaction, thereby preparing a solution of acrylic copolymer with a weight average molecular weight of 560,000 (solid content 35% by weight).

[0216] In the prepared acrylic copolymer solution, 4.0 parts by weight of Coronate HX (manufactured by Tosh Chemical Co., Ltd.) as a crosslinking agent and 0.02 parts by weight of Embilizer OL-1 (manufactured by Tokyo Fine Chemical Co., Ltd.) as a crosslinking catalyst were added relative to 100 parts by weight of its solid content. The solution was diluted with toluene to make the total solid content 25% by weight. The mixture was stirred with a disperser and the resulting acrylic adhesive composition was applied to the release layer side of the separator (2) (a release-treated polyethylene terephthalate film, 38µm thick, trade name "MRF#38", manufactured by Mitsubishi Chemical Co., Ltd.) in a fountain-type roller to make the dried thickness 20µm. The mixture was then cured and dried at a drying temperature of 130°C for 30 seconds. An acrylic adhesive layer was formed on the separator (2) in the above manner.

[0217] Next, the substrate film side (polysiloxane primer untreated side) of the above-obtained laminate (1) is attached to the surface of the acrylic adhesive layer to obtain a double-sided adhesive sheet for transfer having a laminate structure of [separator (1) layer] / [polysiloxane adhesive (1) layer (first adhesive layer)] / [substrate film layer] / [acrylic adhesive layer (second adhesive layer)] / [separator (2) layer].

[0218] <Examples 2-6, Comparative Examples 1 and 2> In the same manner as in Example 1, a polysiloxane adhesive composition containing an ultraviolet absorber (trade name "Tinuvin 384-2, maximum absorption wavelength 345nm, manufactured by BASF") was mixed in at the amount specified in Table 1, and a first adhesive layer was formed in such a way as the thickness specified in Table 1, thereby obtaining double-sided adhesive sheets for transfer printing.

[0219] <Evaluation> The following measurements and evaluations were performed on the double-sided adhesive sheets for transfer obtained in the Examples and Comparative Examples. The results are listed in Table 1.

[0220] (Ultraviolet Transmittance) Thin slices were cut from the first adhesive layer of the transfer double-sided adhesive sheet using a slicing machine, and the transmittance was measured in the wavelength range of 200~800nm ​​using a micro-ultraviolet-visible-near-infrared spectrophotometer (product name "MSV-5200 DGK", manufactured by Japan Spectrophotometer). The value at a wavelength of 248nm was taken as the ultraviolet transmittance TUV1.

[0221] (Raising Height) For the double-sided adhesive sheet used for transfer after peeling off the separation layer (1), ultraviolet laser (wavelength 248nm, laser spot cross-sectional area 15300µm2, output 100mJ / cm2) was irradiated from the polysiloxane adhesive layer side to make 9 points (average irradiation area 15300µm2) in 1mm2. For these 9 points, the surface observation image obtained by laser microscope (product name "VK-X100", manufactured by KEYENCE) was analyzed to obtain the raising height Rz2 after irradiation as the average of the maximum height of each point. Furthermore, for the double-sided adhesive sheet used for transfer before irradiation, the raising height Rz1 before irradiation was obtained from the surface observation image corresponding to the 9 points in the same manner.

[0222] (Raised Area) The double-sided adhesive sheet for transfer after peeling off the separation layer (1) was irradiated with ultraviolet laser (wavelength 248nm, laser beam size 130×105µm (laser spot cross-sectional area 13650µm2, output 100mJ / cm2) with a pulse time of 10nsec and a frequency of 100Hz from the polysiloxane adhesive layer side to make 9 points (average irradiation area 15300µm2) in 1mm2. For each of these 9 points, a surface observation image was taken at a magnification of 200x using a digital microscope (product name "VHX-700F", manufactured by KEYENCE) and analyzed using the image processing software ImageJ to calculate the area where raised areas occurred (raised area) as the average of the 9 points. The area ratio (%) of the raised area was calculated as the area ratio of the raised area to the laser irradiation area of ​​15300µm2.

[0223] (Transfer accuracy) The transfer double-sided adhesive sheet after peeling off the separation piece (1) is attached to the cutting ring with the first adhesive layer as the surface, and cut to a depth of 10µm on the surface of the double-sided adhesive sheet, thereby giving multiple marks with a side length of 1mm.

[0224] A semiconductor wafer pre-processed by laser light is ground to a thickness of 30µm in a manner that allows it to be cut into 1mm×1mm sizes during expansion, and then bonded with a dicing and die-bonding film to obtain a dicing and die-bonding film attached to the semiconductor wafer. The dicing and die-bonding film of the semiconductor wafer is held on the dicing ring of a die separator (product name "DDS2300", manufactured by DISCO). Cold expansion is performed using a cold expansion unit at an expansion temperature of -15°C, an expansion speed of 200 mm / s, and an expansion amount of 11 mm. After the semiconductor wafer and die-bonding layer are cut off, room temperature expansion is performed at room temperature at an expansion speed of 1 mm / s and an expansion amount of 7 mm. While maintaining the expansion state, the dicing tape on the outer periphery of the semiconductor wafer is thermally shrunk at a thermal temperature of 200°C, an air volume of 40 L / min, a thermal distance of 20 mm, and a rotation speed of 3° / s. This process results in a dicing and die-bonding film of the semiconductor wafer with a die-bonding layer, maintaining the state of the semiconductor wafer and die-bonding layer being cut off.

[0225] A double-sided adhesive sheet for transfer, with the die-bonded semiconductor wafer having the die-bonded layer facing down and the marked first adhesive layer facing up, is arranged so that the die-bonded semiconductor wafer is aligned with the marked position and placed opposite each other with a gap of 1 mm. Then, a needle is used to press from the top side (from the back side) of the die-bonded film to make 10 die-bonded semiconductor wafers fall correctly onto the marked positions on the adhesive surface of the first adhesive layer, thereby obtaining a double-sided adhesive sheet for transfer that receives semiconductor wafers.

[0226] For a double-sided adhesive sheet for transfer that receives a semiconductor wafer, an ultraviolet laser (wavelength 248nm, laser spot cross-sectional area 15300µm2, output 100mJ / cm2, frequency 100Hz, pulse width 10ns) is irradiated on the portion of the semiconductor wafer receiving the die-bonded layer to create an alignment mark. A mounting substrate with corresponding markings is set and aligned with the alignment mark. After transferring the semiconductor wafer with the die-bonded layer onto the aligned mounting substrate, the semiconductor wafer with the die-bonded layer is confirmed with a microscope, and the positional accuracy is evaluated according to the following criteria.

[0227] ○: Semiconductor wafers with die-attach layers for which the marking positions on the mounting substrate have not been confirmed to be misaligned. ×: Semiconductor wafers with die-attach layers for which the marking positions on the mounting substrate have been confirmed to be misaligned.

[0228] The double-sided adhesive sheets for transfer, as described in Examples 1 to 6 of the present invention, all suppress the positional shift of the semiconductor wafer caused by ultraviolet laser irradiation. In contrast, the double-sided adhesive sheets for transfer, as described in Comparative Examples 1 and 2, whose ratio (Rz1 / Rz2) exceeds that of the present invention, exhibit positional shift of the semiconductor wafer.

[0229] [Table 1] [Simplified Explanation of the Diagram]

[0012] FIG1 is a cross-sectional schematic diagram showing one embodiment of the double-sided adhesive sheet for transfer printing of the present invention. FIG2 is a cross-sectional schematic diagram showing another embodiment of the double-sided adhesive sheet for transfer printing of the present invention. FIG3 is a cross-sectional schematic diagram showing one embodiment of the first step in a mounting method for mounting electronic components using the double-sided adhesive sheet for transfer printing shown in FIG1 onto a mounting substrate. FIG4 is a cross-sectional schematic diagram showing one embodiment of the second step in a mounting method for mounting electronic components using the double-sided adhesive sheet for transfer printing shown in FIG1 onto a mounting substrate. FIG5 is a cross-sectional schematic diagram showing a double-sided adhesive sheet for transfer printing whose flatness is damaged due to irradiation with ultraviolet laser and whose position is shifted to the received electronic components.

Claims

1. A double-sided adhesive sheet for transfer printing, comprising a first adhesive layer, a substrate, and a second adhesive layer sequentially laminated; wherein the first adhesive layer is composed of a low-adhesion adhesive layer, and the second adhesive layer is composed of a release adhesive layer; the first adhesive layer is irradiated with an ultraviolet laser of wavelength 248nm with a beam size of 130×105µm, an output of 100mJ / cm2, a pulse width of 10ns, and a frequency of 100Hz, and the ratio of the raised height Rz2 after irradiation to the raised height Rz1 before irradiation (Rz2 / Rz1) is 0.2~1600.

2. As in the transfer double-sided adhesive sheet of claim 1, wherein after the first adhesive layer is irradiated with an ultraviolet laser with a beam size of 130×105µm, an output of 100mJ / cm2, a pulse width of 10ns, and a frequency of 100Hz and a wavelength of 248nm, the area ratio of the raised area to the total irradiated area is 20.0% or less.

3. A double-sided adhesive sheet for transfer printing, comprising a first adhesive layer, a substrate, and a second adhesive layer sequentially laminated; wherein the first adhesive layer is composed of a low-adhesion adhesive layer, and the second adhesive layer is composed of a release adhesive layer; after irradiating the first adhesive layer with an ultraviolet laser of wavelength 248nm with a beam size of 130×105µm, an output of 100mJ / cm2, a pulse width of 10ns, and a frequency of 100Hz, the area ratio of the raised area to the total irradiated area is 20.0% or less.

4. For the transfer double-sided adhesive sheet of claim 1 or 2, wherein the ratio (Rz2 / t1) of the aforementioned embossing height Rz2 (µm) to the thickness t1 (µm) of the aforementioned first adhesive layer is 1.0 or less.

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