Electronic component temporary fixing member

Abstract

Provided is an electronic component temporary fixing member capable of reducing residue of the electronic component temporary fixing member on a support when the support is released from the electronic component temporary fixing member.　This electronic component temporary fixing member comprises: a core material; a release layer provided on a first surface of the core material; and an adhesive layer provided on a second surface facing the first surface of the core material. The release layer contains a filler. The electronic component temporary fixing member has a site where the area ratio of the filler in a cross-section in a vertical direction with respect to the first surface of the release layer is 8.0% to 92%.

Description

Temporary fixing material for electronic components

[0001] The present invention relates to a member for temporarily fixing an electronic component that is used when forming a substrate on which electronic components such as semiconductors are mounted.

[0002] In recent years, electronic components such as semiconductors have continued to evolve rapidly, and there is an ever-increasing demand for them to be smaller and thinner. There is also an increasing demand for smaller and thinner substrates on which electronic components such as semiconductors are mounted, and their shapes are becoming more complex every year.

[0003] For example, in the RDL First process, which is one of the techniques for forming fine wiring, a temporary fixing member (temporary fixing material layer) is first formed on a support, and then an RDL layer (rewiring layer) having a thinned substrate is formed on the upper surface of this temporary fixing member. The support has a function of supporting the RDL layer formed on the upper surface of the temporary fixing member on the lower surface of the temporary fixing member. After the RDL layer (rewiring layer) is formed, a laser beam is irradiated from the support side toward the temporary fixing member through the support, thereby separating the support from the temporary fixing member. Then, the temporary fixing member is removed from the RDL layer.

[0004] When the support and the temporary fixing member are separated, it is required that as little residue of the temporary fixing member as possible remains on the support, from the viewpoint of reusing the support, etc. Therefore, a pressure-sensitive adhesive sheet for temporary fixing of electronic components has been proposed, which includes a photothermal conversion layer and a pyrolysis layer disposed directly on the photothermal conversion layer, and in which the 5% weight loss temperature of the pyrolysis layer is lower than the 5% weight loss temperature of the photothermal conversion layer (Patent Document 1).

[0005] In Patent Document 1, the photothermal conversion layer, which is the core material of the temporary fixing material layer, absorbs light of a predetermined wavelength and converts the light into heat; heat generated by the photothermal conversion layer raises the temperature of the pyrolysis layer, which is the release layer of the temporary fixing material layer, resulting in decomposition of the pyrolysis layer. As a result of the decomposition of the pyrolysis layer, the temporary fixing material layer formed on the support exhibits releasability, and the support is peeled off from the temporary fixing material layer. The release layer of the temporary fixing material layer is the layer to which the support is attached. An adhesive layer of the temporary fixing material layer is provided on the core material of the temporary fixing material layer, and a substrate mounted with electronic components, etc. is formed on the adhesive layer.

[0006] However, in the temporary fixing material layer of Patent Document 1, the photothermal conversion layer absorbs laser light, causing the pyrolysis layer to heat up and decompose, thereby exhibiting peelability at the interface between the pyrolysis layer, which is the release layer, and the photothermal conversion layer, which is the core material. When the support is peeled from the temporary fixing material layer, as in the temporary fixing material layer of Patent Document 1, peelability is exhibited at the interface between the release layer and the core material, so residues of the release layer after pyrolysis remain on the support, and there is a need for improvements to reduce the residue on the support. Furthermore, in order to remove the residues of the release layer on the support, it is necessary to wash the support with a solvent, which complicates the manufacturing process of substrates equipped with electronic components and increases the environmental load.

[0007] JP 2023-049530 A

[0008] In view of the above circumstances, an object of the present invention is to provide a temporary electronic component fixing member that can reduce residue of the temporary electronic component fixing member on the support when the support is peeled off from the temporary electronic component fixing member.

[0009] The gist of the configuration of the electronic component temporary fixing member of the present invention is as follows. [1] An electronic component temporary fixing member comprising: a core material, a release layer provided on a first surface of the core material, and an adhesive layer provided on a second surface of the core material opposite the first surface, wherein the release layer contains a filler, and the release layer has a portion in which the area ratio of the filler in a cross section of the release layer in a direction perpendicular to the first surface is 8.0% or more and 92% or less. [2] The electronic component temporary fixing member according to [1], wherein the release layer has a portion in which the transmittance of light with a wavelength of 380 nm in a direction perpendicular to the first surface is 60% or less. [3] The electronic component temporary fixing member according to [1] or [2], wherein the content of the filler in the release layer is 10% by mass or more and 80% by mass or less. [4] The electronic component temporary fixing member according to [1] or [2], wherein the release layer contains a resin that is an adhesive or pressure-sensitive adhesive component, and the filler is contained in an amount of 10 parts by mass or more and 300 parts by mass or less per 100 parts by mass (solid content) of the resin. [5] The electronic component temporary fixing member according to [1] or [2], wherein the particle diameter (D50) of the filler at a cumulative volume percentage of 50% by volume is 0.1 μm or more and 20 μm or less. [6] The electronic component temporary fixing member according to [1] or [2], wherein the filler contains silica. [7] The electronic component temporary fixing member according to [1] or [2], wherein the release layer has a 5% weight loss temperature of 250°C or higher. [8] The electronic component temporary fixing member according to [1] or [2], wherein the 5% weight loss temperature of the electronic component temporary fixing member is 250°C or higher. [9] The electronic component temporary fixing member according to [1] or [2], wherein the core material is made of a polyimide resin or an epoxy resin.

[10] The electronic component temporary fixing member according to [1] or [2], wherein the thickness of the release layer is 1.2 times or more the particle diameter (D90) of the filler at a cumulative volume percentage of 90 volume %.

[11] The electronic component temporary fixing member according to [1] or [2], which is in the form of a tape.

[0010] The electronic component temporary fixing member of the present invention has a laminated structure including a release layer, a core material provided on the release layer, and an adhesive layer provided on the core material and facing the release layer via the core material. A support is attached to the release layer of the electronic component temporary fixing member. Therefore, the support is attached to the release layer in a state facing the core material via the release layer. In addition, a substrate on which electronic components and the like are mounted is formed on the adhesive layer of the electronic component temporary fixing member.

[0011] In the present invention, "area ratio of filler" means the ratio of the area of ​​the filler in the cross section to the total area of ​​the cross section of the release layer in a direction perpendicular to the first surface of the core material, i.e., the ratio of the area of ​​the filler in the cross section to the total area of ​​the cross section in the thickness direction of the release layer.

[0012] According to an embodiment of the electronic component temporary fixing member of the present invention, the release layer has a portion in which the area ratio of the filler in a cross section perpendicular to the first surface is 8.0% or more and 92% or less, thereby reducing residue of the electronic component temporary fixing member on the support when the support is peeled from the electronic component temporary fixing member. That is, in this embodiment of the electronic component temporary fixing member of the present invention, the support can be peeled at the interface between the support and the release layer of the electronic component temporary fixing member, improving the peelability of the release layer from the support. Therefore, according to this embodiment of the electronic component temporary fixing member of the present invention, a cleaning step for removing residue of the release layer on the support is not required, or the cleaning step does not require the use of a solvent, which simplifies the cleaning step and facilitates reuse of the support.

[0013] Furthermore, according to an embodiment of the electronic component temporary fixing member of the present invention, the cleaning process for removing residue of the release layer on the support is unnecessary or simplified, thereby preventing the manufacturing process of a substrate carrying electronic components from becoming complicated and also preventing an increase in the environmental burden.

[0014] According to one aspect of the electronic component temporary fixing member of the present invention, the release layer has a portion in which the transmittance of light with a wavelength of 380 nm in a direction perpendicular to the first surface is 60% or less. This makes it possible to more reliably reduce residue of the electronic component temporary fixing member on the support when the support is peeled off from the electronic component temporary fixing member, thereby further improving the peeling performance of the release layer from the support.

[0015] According to one aspect of the electronic component temporary fixing member of the present invention, the content of the filler in the release layer is 10% by mass or more and 80% by mass or less, so that when the support is peeled off from the electronic component temporary fixing member, residue of the electronic component temporary fixing member on the support can be more reliably reduced, and the peeling performance of the release layer from the support can be further improved.

[0016] According to an embodiment of the electronic component temporary fixing member of the present invention, the release layer contains a resin that is an adhesive component or a pressure-sensitive adhesive component, and contains 10 parts by mass or more and 300 parts by mass or less of the filler per 100 parts by mass (solid content) of the resin. This makes it possible to more reliably reduce residue of the electronic component temporary fixing member on the support when the support is peeled off from the electronic component temporary fixing member, and further improves the peeling performance of the release layer from the support.

[0017] According to an aspect of the electronic component temporary fixing member of the present invention, the particle size (D50) of the filler at a cumulative volume percentage of 50 volume % is 0.1 μm or more and 20 μm or less, and therefore the filler is dispersed uniformly in the release layer, so that the residue of the electronic component temporary fixing member on the support can be reliably reduced, and the release performance of the release layer with respect to the support can be reliably improved.

[0018] According to an aspect of the electronic component temporary fixing member of the present invention, the filler contains silica, so that residue of the electronic component temporary fixing member on the support can be reliably reduced, and the release performance of the release layer from the support is reliably improved.

[0019] According to an embodiment of the electronic component temporary fixing member of the present invention, the 5% weight loss temperature of the release layer is 250° C. or higher, so that the heat resistance of the release layer is improved while maintaining the release performance from the support. Therefore, in the process of forming a rewiring layer or the like, the electronic component temporary fixing member may be exposed to high temperatures of 250° C. or higher for a long time to harden the core material, and the electronic component temporary fixing member can maintain the release performance of the release layer from the support even when exposed to a high-temperature environment for a long time.

[0020] According to an aspect of the electronic component temporary fixing member of the present invention, the 5% weight loss temperature of the electronic component temporary fixing member is 250° C. or higher, so that the heat resistance of the entire electronic component temporary fixing member including the release layer is improved while the release performance of the release layer from the support is obtained. Therefore, even if the electronic component temporary fixing member is exposed to a high-temperature environment for a long period of time, the release performance of the release layer from the support can be maintained.

[0021] According to an aspect of the electronic component temporary fixing member of the present invention, the core material is made of a polyimide resin or an epoxy resin, which improves the heat resistance of the core material, and the electronic component temporary fixing member can maintain its peelability from the support even when exposed to a high-temperature environment for a long period of time.

[0022] According to one aspect of the electronic component temporary fixing member of the present invention, the thickness of the release layer is 1.2 times or more the particle diameter (D90) of the filler when the cumulative volume percentage is 90 volume %, and this makes it possible to stabilize the dispersion state of the filler in the release layer without impairing the adhesiveness and cohesiveness of the release layer to the support, thereby reliably reducing the residue of the electronic component temporary fixing member on the support and reliably improving the release performance of the release layer to the support.

[0023] According to one embodiment of the present invention, the tape-like shape of the electronic component temporary fixing member can improve the dimensional accuracy of the electronic component temporary fixing member in the thickness direction. Also, according to another embodiment of the present invention, the tape-like shape of the electronic component temporary fixing member can eliminate the need to use a solvent when forming the electronic component temporary fixing member by a coating method such as spin coating, thereby preventing an increase in the environmental load.

[0024] The member for temporarily fixing an electronic component of the present invention is used to temporarily fix an electronic component such as a semiconductor when forming a substrate on which the electronic component is mounted.

[0025] <Structure of Electronic Component Temporarily Fixing Member> The electronic component temporarily fixing member of the present invention includes a release layer, a core material provided on the release layer, and an adhesive layer provided on the core material and facing the release layer via the core material. The core material has, for example, a layered shape. That is, the electronic component temporarily fixing member of the present invention has a structure in which the release layer, the core material, and the adhesive layer are laminated in this order.

[0026] Specifically, the layered core material has a first surface forming a main surface and a second surface forming a main surface opposite to the first surface. The member for temporarily fixing an electronic component of the present invention has a laminated structure including a core material, a release layer provided on the first surface of the core material, and an adhesive layer provided on the second surface opposite to the first surface of the core material. As described above, the release layer faces the adhesive layer via the core material.

[0027] The electronic component temporary fixing member of the present invention may have a three-layer structure consisting of a release layer, a core material, and an adhesive layer, or may have a laminate structure having a release layer, a core material, and an adhesive layer, i.e., a laminate structure having other layers in addition to the release layer, the core material, and the adhesive layer. In the case of a three-layer structure consisting of a release layer, a core material, and an adhesive layer, no other layer is disposed between the release layer and the core material, and the release layer and the core material are in contact, and no other layer is disposed between the core material and the adhesive layer, and the core material and the adhesive layer are in contact.

[0028] <Release Layer of Electronic Component Temporarily Fixing Member> The release layer of the electronic component temporary fixing member of the present invention is the portion to which the support is attached. The support is attached to the lower surface of the release layer in a state facing the first surface of the core material. The support has the function of supporting a substrate mounted with electronic components such as semiconductors, such as an RDL layer, formed on the upper surface of the adhesive layer of the electronic component temporary fixing member, on the lower surface of the release layer of the electronic component temporary fixing member. Therefore, the support is attached to the release layer in a state facing the core material and the adhesive layer via the release layer. After forming a substrate mounted with electronic components such as semiconductors, such as an RDL layer, on the upper surface of the adhesive layer, the support is separated from the electronic component temporary fixing member by irradiating a laser beam (wavelength, for example, 250 nm to 400 nm) from the support side toward the temporary fixing member via the support.

[0029] The release layer of the electronic component temporary fixing member of the present invention contains an adhesive or pressure-sensitive adhesive component as an adhesive component, and a filler as an additive. The release layer contains the adhesive or pressure-sensitive adhesive component as an adhesive component, so that the support is adhered or stuck to the release layer. Note that the release layer may contain additives other than the filler, such as a silane coupling agent, as necessary.

[0030] Examples of the adhesive component (main component) of the adhesive include epoxy resin, bismaleimide resin, etc. These resins as adhesive components may be used alone or in combination.

[0031] The epoxy resin is not particularly limited, and examples thereof include phenol novolac type epoxy resins, ortho-cresol novolac type epoxy resins, cresol novolac type epoxy resins, dicyclopentadiene type epoxy resins, biphenyl type epoxy resins, biphenyl aralkyl type epoxy resins, phenyl aralkyl type epoxy resins, fluorene bisphenol type epoxy resins, triazine type epoxy resins, naphthol type epoxy resins, naphthalenediol type epoxy resins, triphenylmethane type epoxy resins, tetraphenyl type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AD ​​type epoxy resins, bisphenol S type epoxy resins, and trimethylolmethane type epoxy resins.

[0032] The epoxy equivalent of the epoxy resin is not particularly limited and can be appropriately selected depending on the conditions of use, etc., and can be, for example, 150 g / eq or more and 450 g / eq or less. The mass average molecular weight of the epoxy resin is also not particularly limited and can be appropriately selected depending on the conditions of use, etc., and is, for example, preferably 300 or more and 10,000 or less, and particularly preferably 500 or more and 5,000 or less. The above-mentioned "mass average molecular weight" refers to the mass average molecular weight measured at room temperature using gel permeation chromatography (GPC) and calculated in polystyrene equivalent terms.

[0033] The adhesive may also contain a binder such as a phenoxy resin, (meth)acrylic resin, or urethane resin, as needed. Phenoxy resins can be obtained by reacting a bisphenol or biphenol compound with an epihalohydrin such as epichlorohydrin, or by reacting a liquid epoxy resin with a bisphenol or biphenol compound. Examples of bisphenol or biphenol compounds include bisphenol A, bisphenol AD, bisphenol AP, bisphenol AF, bisphenol B, bisphenol BP, bisphenol C, bisphenol E, bisphenol F, bisphenol G, bisphenol M, bisphenol S, bisphenol P, bisphenol PH, bisphenol TMC, and bisphenol Z; as well as 4,4'-biphenol, 2,2'-dimethyl-4,4'-biphenol, 2,2',6,6'-tetramethyl-4,4'-biphenol, and cardo skeleton bisphenols. Examples of liquid epoxy resins include diglycidyl ethers of aliphatic diol compounds. Examples of the aliphatic diol compound in the diglycidyl ether include ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-heptanediol, 1,6-hexanediol, 1,7-pentanediol, and 1,8-octanediol.

[0034] The epoxy equivalent of the phenoxy resin is not particularly limited and can be appropriately selected depending on the conditions of use, etc., and is, for example, 5,000 g / eq or more and 100,000 g / eq or less. The mass average molecular weight of the phenoxy resin is not particularly limited and can be appropriately selected depending on the conditions of use, etc., and is, for example, preferably 10,000 or more and 200,000 or less, and particularly preferably 20,000 or more and 100,000 or less.

[0035] The adhesive may contain an epoxy resin curing agent as a curing agent, if necessary. Examples of epoxy resin curing agents include amines, acid anhydrides, and polyhydric phenols. For the electronic component temporary fixing member of the present invention, a latent curing agent is preferred because it provides an adhesive with low melt viscosity, high-temperature curing properties, rapid curing properties, and high storage stability that allows for long-term storage at room temperature. Examples of latent curing agents include dicyandiamide compounds, imidazole compounds, curing catalyst composite polyhydric phenol compounds, hydrazide compounds, boron trifluoride-amine complexes, amine imide compounds, polyamine salts, and modified or microencapsulated versions of these. These epoxy resin curing agents may be used alone or in combination.

[0036] The content of the epoxy resin curing agent is not particularly limited, but the lower limit is preferably 0.5 parts by mass, more preferably 1.0 parts by mass, and particularly preferably 1.5 parts by mass, relative to 100 parts by mass of the adhesive component (main component) of the adhesive, from the viewpoint of shortening the curing time of the adhesive component (main component) of the adhesive. On the other hand, the upper limit of the content of the epoxy resin curing agent is preferably 7.0 parts by mass, more preferably 5.0 parts by mass, and particularly preferably 4.0 parts by mass, relative to 100 parts by mass of the adhesive component (main component) of the adhesive, from the viewpoint of preventing a decrease in adhesive reliability due to the epoxy resin curing agent remaining in the adhesive and absorbing moisture.

[0037] The pressure-sensitive adhesive has the function of imparting adhesion to the core material to the release layer. On the other hand, in order to enable peeling of the support at the interface between the support and the release layer of the electronic component temporary fixing member, it is preferable that the adhesion to the support is lower than the adhesion to the core material, that is, the peelability from the support is higher than the peelability from the core material. Examples of the adhesive component (main component) of the pressure-sensitive adhesive include (meth)acrylic resin, silicone, urethane resin, etc.

[0038] Examples of (meth)acrylic resins include resins made of (meth)acrylic (co)polymers (co)polymers of (meth)acrylic monomers). Examples of (meth)acrylic resins include poly(meth)acrylic acid esters or derivatives thereof. Examples of (meth)acrylic monomer components constituting (meth)acrylic resins include ethylenically unsaturated group-containing carboxylic acids such as acrylic acid, methacrylic acid, and itaconic acid; (meth)acrylic acid esters having a hydroxyl group such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, and 2-hydroxypropyl methacrylate; and (meth)acrylic acid esters having an epoxy group such as glycidyl methacrylate and glycidyl acrylate. Examples of monomer components constituting the (meth)acrylic resin include (meth)acrylic acid esters having a cyclic skeleton, such as (meth)acrylic acid cycloalkyl esters, (meth)acrylic acid benzyl esters, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, and dicyclopentenyloxyethyl (meth)acrylate; imide (meth)acrylates; and (meth)acrylic acid alkyl esters in which the alkyl group has 1 to 18 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, and butyl (meth)acrylate. These (meth)acrylic monomer components may be used alone, or two or more types may be used in combination.

[0039] The (meth)acrylic resin may be copolymerized with other monomers such as vinyl acetate, (meth)acrylonitrile, and styrene in addition to the above-mentioned (meth)acrylic monomers.

[0040] The mass average molecular weight of the (meth)acrylic resin is not particularly limited and can be appropriately selected depending on the conditions of use, etc. For example, it is preferably 10,000 or more and 2,000,000 or less, and particularly preferably 100,000 or more and 1,500,000 or less.

[0041] When a (meth)acrylic resin is used as the adhesive component of the adhesive, additives such as a (meth)acrylic resin curing agent and an isocyanate compound may be blended as needed. Furthermore, by blending a (meth)acrylic resin curing agent and an isocyanate compound, the adhesive strength of the adhesive can be appropriately adjusted depending on the conditions of use of the member for temporarily fixing electronic components. Examples of (meth)acrylic resin curing agents include polyfunctional epoxy resins such as 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane and N,N,N',N'-tetraglycidyl-m-xylenediamine.

[0042] The content of the (meth)acrylic resin curing agent is not particularly limited as long as it is a content that allows the adhesive strength of the adhesive to be adjusted to a desired range depending on the conditions of use of the electronic component temporary fixing member, etc. For example, the lower limit is preferably 0.1 parts by mass, more preferably 0.2 parts by mass, and particularly preferably 0.3 parts by mass, relative to 100 parts by mass of the adhesive component (main component) of the adhesive. On the other hand, the upper limit of the content of the (meth)acrylic resin curing agent is preferably 3.0 parts by mass, more preferably 2.0 parts by mass, and particularly preferably 1.0 part by mass, relative to 100 parts by mass of the adhesive component (main component) of the adhesive.

[0043] In the electronic component temporary fixing member of the present invention, the release layer contains a filler. Also, in the electronic component temporary fixing member of the present invention, the content of the filler is adjusted so that the release layer has a region in a cross section perpendicular to the first surface of the core material where the area ratio of the filler is 8.0% or more and 92% or less. That is, the content of the filler is adjusted so that the release layer has a region in a cross section in the thickness direction of the release layer where the area ratio of the filler is 8.0% or more and 92% or less.

[0044] In the electronic component temporary fixing member of the present invention, the release layer contains a filler, and therefore the release layer has the ability to absorb laser light with a wavelength of 250 nm to 400 nm. Furthermore, since the release layer has a region where the area ratio of the filler in the cross section in the thickness direction of the release layer is 8.0% or more and 92% or less, when laser light with a wavelength of 250 nm to 400 nm is irradiated from the support side through the support toward the electronic component temporary fixing member of the present invention, the laser light is absorbed by the release layer, causing the release layer to decompose. As a result, the support is peeled from the electronic component temporary fixing member at the interface between the support and the release layer. Furthermore, when the support is peeled from the electronic component temporary fixing member of the present invention, residue of the electronic component temporary fixing member on the support can be reduced. In other words, smooth peeling of the support is possible at the interface between the support and the release layer of the electronic component temporary fixing member, and the peeling performance of the release layer relative to the support is improved. Therefore, with the electronic component temporary fixing member of the present invention, a cleaning step for removing residue of the release layer on the support is not required, or there is no need to use a solvent in the cleaning step, and the cleaning step is simplified, making it easier to reuse the support.

[0045] Furthermore, with the electronic component temporary fixing member of the present invention, the cleaning process for removing residue of the release layer on the support is unnecessary or simplified, thereby preventing the manufacturing process for substrates carrying electronic components from becoming complicated and also preventing an increase in environmental load.

[0046] The release layer may have at least some regions in which the area ratio of the filler in the cross section of the release layer in the thickness direction is 8.0% or more and 92% or less, but in order to reliably improve the release performance of the release layer relative to the support, it is preferable that the area ratio of the filler in the cross section of the release layer in the thickness direction be 8.0% or more and 92% or less throughout the entire release layer.

[0047] The area ratio of the filler in the cross section of the thickness direction of the release layer is not particularly limited as long as it is in the range of 8.0% to 92% but the lower limit is preferably 9.0%, particularly preferably 10%, from the viewpoint of further improving the release performance of the release layer from the support. On the other hand, the upper limit of the area ratio of the filler in the cross section of the thickness direction of the release layer is preferably 70%, more preferably 60%, particularly preferably 55%, from the viewpoint of reliably obtaining the adhesiveness and cohesiveness of the release layer.

[0048] The transmittance of the release layer for light having a wavelength of 380 nm in a direction perpendicular to the first surface of the core material is not particularly limited. However, in order to further reliably reduce residue of the electronic component temporary fixing member on the support when the support is peeled from the electronic component temporary fixing member and further improve the peeling performance of the release layer from the support, it is preferable for the release layer to have a portion where the light transmittance is 60% or less. It is more preferable that the light transmittance be 60% or less throughout the entire release layer, and particularly preferable that the light transmittance be 55% or less throughout the entire release layer. The light transmittance can be adjusted by adjusting the filler content. Adjusting the filler content so that the area ratio of the filler in the cross section of the release layer in the thickness direction is in the range of 8.0% to 92% makes it easier to adjust the light transmittance to 60% or less. The lower limit of the transmittance of light having a wavelength of 380 nm in a direction perpendicular to the first surface of the core material is preferably 0% in order to reliably impart adhesiveness and cohesion to the release layer.

[0049] The content of the filler in the release layer is not particularly limited as long as the area ratio of the filler in the cross section in the thickness direction of the release layer is in the range of 8.0% to 92%, but the lower limit is preferably 10% by mass, more preferably 13% by mass, and particularly preferably 20% by mass, from the viewpoint of further reliably reducing the residue of the electronic component temporary fixing member on the support when the support is peeled from the electronic component temporary fixing member and further improving the peel performance of the release layer from the support. On the other hand, the upper limit of the content of the filler in the release layer is preferably 80% by mass, more preferably 75% by mass, and particularly preferably 70% by mass, from the viewpoint of reliably obtaining the adhesiveness and cohesiveness of the release layer.

[0050] In a release layer containing a resin as an adhesive or pressure-sensitive adhesive component, the content of the filler per 100 parts by mass (solid content) of the resin is not particularly limited as long as the area ratio of the filler in the cross section of the thickness direction of the release layer is in the range of 8.0% to 92%. However, the lower limit is preferably 10 parts by mass, more preferably 15 parts by mass, and particularly preferably 30 parts by mass per 100 parts by mass (solid content) of the resin, in order to further reliably reduce the residue of the electronic component temporary fixing member on the support when the support is peeled from the electronic component temporary fixing member and further improve the peel performance of the release layer from the support. On the other hand, the upper limit of the filler content per 100 parts by mass (solid content) of the resin is preferably 300 parts by mass, more preferably 250 parts by mass, and particularly preferably 200 parts by mass, in order to reliably obtain the adhesiveness and tackiness of the release layer.

[0051] The filler is a particulate component, and examples of the shape of the filler include spherical. The particle diameter (D50) of the filler at a cumulative volume percentage of 50% by volume is not particularly limited, but is preferably 0.1 μm or more and 20 μm or less, particularly preferably 0.5 μm or more and 10 μm or less, from the viewpoints that the dispersion state of the filler in the release layer is made uniform, the residue of the electronic component temporary fixing member on the support can be reliably reduced, and the release performance of the release layer from the support can be reliably improved.

[0052] The particle size (D90) of the filler at a cumulative volume percentage of 90% by volume is not particularly limited, but is preferably 1.0 μm or more and 35 μm or less, and particularly preferably 2.0 μm or more and 25 μm or less, from the viewpoint of uniformly dispersing the filler in the release layer, reliably reducing the residue of the electronic component temporary fixing member on the support, and reliably improving the release performance of the release layer from the support. Furthermore, the particle size (D10) of the filler at a cumulative volume percentage of 10% by volume is not particularly limited, but is preferably 0.03 μm or more and 5.0 μm or less, and particularly preferably 0.05 μm or more and 3.0 μm or less, from the viewpoint of uniformly dispersing the filler in the release layer, reliably reducing the residue of the electronic component temporary fixing member on the support, and reliably improving the release performance of the release layer from the support.

[0053] The relationship between the particle size of the filler and the thickness of the release layer is not particularly limited, but it is possible to stabilize the dispersion state of the filler in the release layer without impairing the adhesiveness and cohesiveness of the release layer to the support, thereby reliably reducing the residue of the electronic component temporary fixing member on the support, and reliably improving the release performance of the release layer to the support. In order to reliably improve the release performance of the release layer to the support, the thickness of the release layer is preferably 1.2 times or more, more preferably 1.5 times or more, and particularly preferably 2.0 times or more, of the particle size (D90) of the filler at a cumulative volume percentage of 90% by volume. In addition, in order to reliably obtain the release performance of the release layer to the support, the thickness of the release layer is preferably 10 times or less, particularly preferably 5.0 times or less, of the particle size (D90) of the filler at a cumulative volume percentage of 90% by volume. Note that the D10, D50, and D90 of the filler refer to particle sizes measured using a laser diffraction / scattering method with a particle size distribution analyzer.

[0054] Examples of fillers include inorganic fillers. Examples of inorganic fillers include ceramics such as silica, clay, gypsum, calcium carbonate, barium sulfate, alumina (aluminum oxide), beryllium oxide, magnesium oxide, silicon carbide, silicon nitride, aluminum nitride, and boron nitride; metals such as aluminum, copper, silver, gold, nickel, chromium, tin, zinc, palladium, and solder; and inorganic powders such as carbons such as carbon nanotubes and graphene. Among these, it is preferable to contain silica, alumina, silver, or copper as a filler, as these have excellent absorption characteristics for laser light with a wavelength of 250 nm to 400 nm, can reliably reduce residue of the electronic component temporary fixing member on the support, and reliably improve the release performance of the release layer from the support.

[0055] In the electronic component temporary fixing member of the present invention, a silane coupling agent may be blended into the release layer as needed. By blending a silane coupling agent into the release layer, the dispersibility of the filler in the adhesive component and the pressure-sensitive adhesive component is improved. Specifically, when an epoxy resin is used as the adhesive component, a silane coupling agent for epoxy may be blended, and when a (meth)acrylic resin is used as the pressure-sensitive adhesive component, a silane coupling agent for (meth)acrylic may be blended. The silane coupling agent for epoxy is a silane coupling agent having an epoxy group as the organic functional group. The silane coupling agent for (meth)acrylic is a silane coupling agent having a (meth)acrylic group as the organic functional group.

[0056] Examples of silane coupling agents include 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, and 3-methacryloyloxypropyltriethoxysilane.

[0057] The content of the silane coupling agent is not particularly limited, and for example, from the viewpoint of reliably improving the dispersibility of the filler while suppressing the generation of outgassing, it is preferably 0.1 parts by mass or more and 5.0 parts by mass or less, and particularly preferably 0.3 parts by mass or more and 3.0 parts by mass or less, relative to 100 parts by mass of the filler.

[0058] The 5% weight loss temperature of the release layer is not particularly limited, but is preferably 250°C or higher, more preferably 300°C or higher, and particularly preferably 330°C or higher, from the viewpoint of improving the heat resistance of the release layer while maintaining the release performance of the release layer from the support. In the process of forming a rewiring layer, etc., the electronic component temporary fixing member may be exposed to high temperatures of 250°C or higher for a long time to harden the core material. By improving the heat resistance of the release layer, the release performance of the release layer from the support can be maintained even when the electronic component temporary fixing member is exposed to a high-temperature environment for a long time. An example of the upper limit of the 5% weight loss temperature of the release layer is 500°C.

[0059] The "5% weight loss temperature" refers to the temperature at which the mass of a sample to be evaluated decreases by 5% when the sample is heated, compared to the mass before heating. This temperature is measured using a differential thermal analyzer under the following measurement conditions: a heating rate of 10°C / min, a nitrogen atmosphere, and a flow rate of 50 ml / min.

[0060] The thickness of the release layer is not particularly limited and can be appropriately selected depending on the conditions of use of the electronic component temporary fixing member, and may be, for example, 3 μm or more and 100 μm or less.

[0061] <Core material of member for temporarily fixing electronic components> The core material of the member for temporarily fixing electronic components of the present invention is a base material that maintains the shape of the member for temporarily fixing electronic components, and has the functions of supporting a release layer on a first surface of the core material and supporting a pressure-sensitive adhesive layer, which will be described later, on a second surface of the core material.

[0062] The material of the core material is not particularly limited, and examples thereof include resins having imide bonds such as polyimide resins, polyesters such as polyethylene terephthalate and polyethylene naphthalate, epoxy resins, phenoxy resins, etc. Among these, the core material is preferably made of a heat-resistant material, from the viewpoint of improving the heat resistance of the core material and maintaining the peel performance of the electronic component temporary fixing member from the support even when the electronic component temporary fixing member is exposed to a high-temperature environment for a long period of time, and is preferably made of, for example, polyethylene naphthalate, a polyimide resin, or an epoxy resin, and is particularly preferably made of a polyimide resin or an epoxy resin, from the viewpoint of further improving heat resistance.

[0063] The first and second surfaces of the core material may be surface-modified by corona treatment, etc., as needed. By performing surface modification by corona treatment, etc., the adhesion of the first surface to the release layer is improved, and the adhesion of the second surface to the adhesive layer is improved.

[0064] The core material has a shape of, for example, a layer, a sheet, or a tape. The thickness of the core material is not particularly limited and can be appropriately selected depending on the conditions of use of the member for temporarily fixing electronic components, and can be, for example, 5 μm or more and 100 μm or less.

[0065] <Adhesive Layer of Electronic Component Temporarily Fixing Member> The adhesive layer of the electronic component temporarily fixing member of the present invention is a portion to which a semiconductor substrate or the like to be processed is bonded, and the semiconductor substrate or the like to be processed is processed on the adhesive layer to form a substrate mounted with desired electronic components, etc. After the substrate mounted with the desired electronic components, etc. is formed, the formed substrate mounted with electronic components, etc. can be peeled off from the adhesive layer, thereby removing the substrate mounted with electronic components, etc. from the electronic component temporarily fixing member.

[0066] Examples of adhesive components (main components) of the adhesive layer include (meth)acrylic polymers, silicones, and urethane resins. Constituent components of the (meth)acrylic polymer include (meth)acrylic acid ester components, (meth)acrylic acid components, (meth)acrylamide components, and (meth)acrylonitrile components. Among these, it is preferable for the (meth)acrylic polymer to contain a (meth)acrylic acid ester component. The (meth)acrylic polymer preferably contains 50% by mass or more of the (meth)acrylic acid ester component, more preferably 70% by mass or more, and particularly preferably 80% by mass or more.

[0067] Examples of monomers that derive a (meth)acrylic acid ester component of the (meth)acrylic polymer include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, and methyl (meth)acrylate. Examples of such compounds include alkyl (meth)acrylates such as isodecyl acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, and octadecyl (meth)acrylate; cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate; aryl (meth)acrylates such as phenyl (meth)acrylate; and hydroxyl group-containing (meth)acrylates such as 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate. These compounds may be used alone or in combination of two or more.

[0068] The adhesive layer may contain additives such as a (meth)acrylic resin curing agent and an isocyanate compound, as needed. Furthermore, by incorporating a (meth)acrylic resin curing agent and an isocyanate compound, the adhesive layer can be imparted with high-temperature curing properties and rapid curing properties. Examples of (meth)acrylic resin curing agents include polyfunctional epoxy resins such as 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane and N,N,N',N'-tetraglycidyl-m-xylenediamine.

[0069] The content of the (meth)acrylic resin curing agent is not particularly limited, but the lower limit is preferably 0.1 parts by mass, more preferably 0.2 parts by mass, and particularly preferably 0.3 parts by mass relative to 100 parts by mass of the (meth)acrylic polymer from the viewpoint of shortening the curing time of the (meth)acrylic polymer, while the upper limit of the content of the (meth)acrylic resin curing agent is preferably 3.0 parts by mass, more preferably 2.0 parts by mass, and particularly preferably 1.0 part by mass relative to 100 parts by mass of the (meth)acrylic polymer.

[0070] The thickness of the adhesive layer is not particularly limited and can be appropriately selected depending on the conditions of use of the electronic component temporary fixing member, and may be, for example, from 5 μm to 100 μm.

[0071] <Properties of the Electronic Component Temporary Fixing Member as a Whole> The 5% weight loss temperature of the electronic component temporary fixing member is not particularly limited, but is preferably 250°C or higher, more preferably 300°C or higher, and particularly preferably 330°C or higher, in order to obtain the release performance of the release layer from the support while improving the heat resistance of the entire electronic component temporary fixing member including the release layer. In the process of forming a rewiring layer, etc., the electronic component temporary fixing member may be exposed to high temperatures of 250°C or higher for a long time to harden the core material. By improving the heat resistance of the entire electronic component temporary fixing member, the release performance of the release layer from the support can be maintained even when the electronic component temporary fixing member is exposed to a high-temperature environment for a long time. An example of the upper limit of the 5% weight loss temperature of the electronic component temporary fixing member is 500°C.

[0072] The shape of the electronic component temporary fixing member can be appropriately selected depending on the conditions of use of the electronic component temporary fixing member, and examples thereof include a tape shape, a sheet shape, and the like. When the shape of the electronic component temporary fixing member is a tape shape or a sheet shape, the dimensional accuracy of the electronic component temporary fixing member in the thickness direction can be improved. Furthermore, when the shape of the electronic component temporary fixing member of the present invention is a tape shape or a sheet shape, there is no need to use a solvent when forming the electronic component temporary fixing member by a coating method such as spin coating, and therefore an increase in the environmental burden can be prevented.

[0073] The electronic component temporary fixing member can be stored for a long period of time by attaching a cover separator to each of the outer surfaces of the release layer and the adhesive layer. When using the electronic component temporary fixing member, the cover separator attached to the outer surface of the release layer is peeled off and a support is attached, and the cover separator attached to the outer surface of the adhesive layer is peeled off and a semiconductor substrate or the like to be processed is attached.

[0074] Next, examples of the present invention will be described, but the present invention is not limited to these examples as long as they do not depart from the spirit of the present invention.

[0075] [Preparation of Electronic Component Temporary Fixing Member] [Example 1] Preparation of Release Layer 50 parts by mass of a liquid epoxy resin (trade name: YD-128, bisphenol A type epoxy resin, mass average molecular weight: 400, epoxy equivalent: 190, Nippon Steel Chemical & Material Co., Ltd.), 20 parts by mass of a solid epoxy resin (trade name: EPPN-501H, triphenylmethane type epoxy resin, mass average molecular weight: 1000, epoxy equivalent: 167, Nippon Kayaku Co., Ltd.), and 30 parts by mass of a phenoxy resin (trade name: YP-50, bisphenol A type phenoxy resin, mass average molecular weight: 70000, Nippon Steel Chemical & Material Co., Ltd.) were heated and stirred together with methyl ethyl ketone (MEK) in a 1000 ml separable flask at a temperature of 110°C for 2 hours to obtain a resin varnish. The resulting resin varnish was then transferred to an 800 ml planetary mixer, and a particulate silica filler (trade name: FB-5SDX, D10: 1.1 μm, D50: 4.2 μm, D90: 9.5 μm, specific surface area: 2.7 m) was added as a filler. ２ To the mixture was added 70 parts by mass of an epoxy resin curing agent (product name: 2PHZ-PW, epoxy resin curing agent, Shikoku Kasei Co., Ltd.) and 3 parts by mass of an epoxy silane coupling agent (product name: KBM-403, 3-glycidoxypropyltrimethoxysilane, Shin-Etsu Silicones Co., Ltd.), and the mixture was stirred and mixed at room temperature for 1 hour, followed by vacuum degassing to obtain a mixed varnish. The resulting mixed varnish was then applied to the first surface of a 25 μm-thick polyimide film serving as a core material, and dried by heating at 130°C for 5 minutes to obtain a film in which a 20 μm-thick release layer was laminated on one surface (first surface) of the core material.

[0076] At this time, for the purpose of evaluating the parallel ray transmittance (light wavelength 380 nm) of the release layer, the mixed varnish of the release layer obtained as described above was applied to a release-treated PET film (release film) with a thickness of 38 μm, and then heated and dried at 130°C for 5 minutes to also prepare a sample for evaluating parallel ray transmittance, which was a release layer with a release film.

[0077] Preparation of adhesive layer: 100 parts by weight of 2-ethylhexyl acrylate (HA), 8 parts by weight of 2-hydroxyethyl acrylate, 0.3 parts by weight of azobisisobutyronitrile, and 60 parts by weight of ethyl acetate were placed in a reaction vessel equipped with a cooling tube, a nitrogen inlet tube, a thermometer, and a stirrer, and the mixture was subjected to a polymerization reaction at 65 ° C. for 6 hours in a nitrogen stream to obtain an acrylic polymer solution. 0.5 parts by weight of an epoxy compound (trade name: Tetrad C, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, Mitsubishi Gas Chemical Company, Inc.) was added as an acrylic resin curing agent (crosslinking agent) to 100 parts by weight of the acrylic polymer to prepare an adhesive solution. The obtained adhesive solution was applied to a release-treated PET film (release film), heated and dried at 120 ° C. for 2 minutes, and a 20 μm thick adhesive layer was formed.

[0078] Preparation of a temporary fixing member for electronic components The adhesive layer on the obtained release film was transferred to the surface (second surface) of the core material opposite to the release layer, thereby obtaining a temporary fixing member for electronic components of Example 1.

[0079] [Example 2] A temporary fixing member for electronic components was obtained in the same manner as in Example 1, except that the amount of silica filler added to the release layer was 15 parts by mass and the amount of silane coupling agent for epoxy resins was 0.075 parts by mass.

[0080] [Example 3] A member for temporarily fixing electronic components was obtained in the same manner as in Example 1, except that the amount of silica filler added to the release layer was 230 parts by mass and the amount of silane coupling agent for epoxy resins was 1.15 parts by mass.

[0081] Example 4 In producing the release layer, instead of the resin varnish using the epoxy resin and the phenoxy resin, a resin varnish using an acrylic resin prepared as described below was used, instead of the epoxy resin curing agent, 0.5 parts by mass of an acrylic resin curing agent (trade name: Tetrad C, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, Mitsubishi Gas Chemical Company, Inc.) was added, the amount of silica filler added to the release layer was 140 parts by mass, instead of the silane coupling agent for epoxy, 0.7 parts by mass of a silane coupling agent for acrylic (trade name: KBM-503, 3-methacryloyloxypropyltrimethoxysilane, Shin-Etsu Silicones Co., Ltd.) was added, and a film having a release layer with a thickness of 20 μm laminated on one side (first side) of the core material was allowed to stand at room temperature (25° C.) for one week before producing the adhesive layer. An electronic component temporary fixing member was obtained in the same manner as in Example 1, except for this.

[0082] Preparation of Resin Varnish Using Acrylic Resin Into a reaction vessel equipped with a condenser, a nitrogen inlet tube, a thermometer, and a stirrer, 100 parts by mass of 2-ethylhexyl acrylate (HA), 8 parts by mass of 2-hydroxyethyl acrylate, 0.3 parts by mass of azobisisobutyronitrile, and 60 parts by mass of ethyl acetate were placed, and a polymerization reaction was carried out in a nitrogen stream at 65°C for 6 hours to obtain an acrylic polymer solution.

[0083] Example 5 A member for temporarily fixing electronic components was obtained in the same manner as in Example 4, except that the amount of silica filler added to the release layer was 90 parts by mass and the amount of silane coupling agent for acrylic was 0.45 parts by mass.

[0084] Example 6 A member for temporarily fixing electronic components was obtained in the same manner as in Example 4, except that the amount of silica filler added to the release layer was 200 parts by mass and the amount of silane coupling agent for acrylic was 1.0 part by mass.

[0085] Example 7 A member for temporarily fixing electronic components was obtained in the same manner as in Example 1, except that polyethylene naphthalate was used for the core material instead of the polyimide film.

[0086] Example 8 A member for temporarily fixing electronic components was obtained in the same manner as in Example 1, except that a film made of epoxy resin was used as the core material instead of the polyimide film.

[0087] The method for producing an epoxy resin film is as follows. 50 parts by mass of epoxy resin (trade name: YD-128, bisphenol A-type epoxy resin, mass average molecular weight: 400, epoxy equivalent: 190, Nippon Steel Chemical & Material Co., Ltd.), 50 parts by mass of phenoxy resin (trade name: YP-50, bisphenol A-type phenoxy resin, mass average molecular weight: 70,000, Nippon Steel Chemical & Material Co., Ltd.), and 1 part of a heat curing agent (trade name: SI-300, thermal acid generator, Sanshin Chemical Co., Ltd.) were dissolved in methyl ethyl ketone to obtain a composition containing an epoxy compound. The obtained composition containing an epoxy compound was coated using a comma coater, dried at 130°C for 3 minutes, and then heated at 110°C for 3 hours for heat curing treatment to obtain a substrate film (25 μm).

[0088] Comparative Example 1 A temporary electronic component-fixing member was obtained in the same manner as in Example 1, except that the silica filler and the silane coupling agent for epoxy resins were not blended into the release layer.

[0089] Comparative Example 2 A member for temporarily fixing electronic components was obtained in the same manner as in Example 1, except that the amount of silica filler added to the release layer was 5 parts by mass and the amount of silane coupling agent for epoxy resins was 0.025 parts by mass.

[0090] Comparative Example 3 A temporary electronic component-fixing member was obtained in the same manner as in Example 4, except that the silica filler and the acrylic silane coupling agent were not blended into the release layer.

[0091] Comparative Example 4 A member for temporarily fixing electronic components was obtained in the same manner as in Example 4, except that the amount of silica filler added to the release layer was 8 parts by mass and the amount of silane coupling agent for acrylic was 0.04 parts by mass.

[0092] [Comparative Example 5] A member for temporarily fixing electronic components was obtained in the same manner as in Example 1, except that the amount of silica filler added to the release layer was 10 parts by mass, the amount of silane coupling agent for epoxy was 0.05 parts by mass, and polyethylene terephthalate was used instead of the polyimide film for the core material.

[0093] The evaluation items of the members for temporarily fixing electronic components of the examples and comparative examples are as follows.

[0094] (1) Area ratio of filler in the cross section in the thickness direction of the release layer (filler-containing area ratio of the release layer) (unit: %) The electronic component temporary fixing members of the Examples and Comparative Examples were embedded in resin (Nissin EM Co., Ltd., NER-814), and the embedded electronic component temporary fixing members were mechanically polished to expose the cross section in the thickness direction of the electronic component temporary fixing member. The exposed cross section was then subjected to ion milling using an ion milling device (Hitachi High-Tech Corporation, IM4000II). Conductive treatment was then performed, and FE-SEM observation was performed. The FE-SEM was performed at an acceleration voltage of 1 kV to 5 kV, and a backscattered electron image was observed. The captured image was binarized using image analysis software Image-J to identify the filler, and the area ratio of the filler in the cross section in the thickness direction of the release layer was calculated from the filler area of ​​the image using the following formula (A). Area ratio (%) of filler in cross section in thickness direction of release layer = area of ​​filler in cross section in thickness direction of release layer / cross-sectional area in thickness direction of release layer ... formula (A)

[0095] (2) Parallel ray transmittance of release layer (light wavelength 380 nm) The release layer on the release film was heat-attached to a glass plate at 70°C, and then the release film was peeled off to obtain a glass sample with a release layer. The transmittance of the glass plate alone was used as a baseline, and the parallel ray transmittance of light with a wavelength of 380 nm (transmittance in the thickness direction of the release layer) of the release layer was measured using a spectrophotometer (Hitachi High-Technologies Corporation, Spectrophotometer U-4100 Solid Sample Measurement System).

[0096] In Examples 1, 2, 3, 7, and 8 and Comparative Examples 1, 2, and 5, the glass samples with the release layer were heated at 150°C for 1 hour before measuring the parallel ray transmittance, while in Examples 4, 5, and 6 and Comparative Examples 3 and 4, the glass samples with the release layer were not heat-treated and the parallel ray transmittance was measured immediately.

[0097] (3) 5% Weight Loss Temperature In Examples 1, 2, 3, 7, and 8 and Comparative Examples 1, 2, and 5, after heating at 150°C for 1 hour, and in Examples 4, 5, and 6 and Comparative Examples 3 and 4, without heat treatment, 10 mg of the sample (release layer, electronic component temporary fixing member) was weighed out and placed in an alumina sample pan. Thermal analysis was performed using a simultaneous differential thermal and thermogravimetric analyzer (product name: TG / DTA320, Seiko Instruments Inc.) under a nitrogen atmosphere at a flow rate of 50 mL / min and a heating rate of 10°C / min from room temperature to 500°C. The temperature at which the sample mass decreased by 5% (the temperature at which the sample mass reached 9.5 mg) was defined as the 5% weight loss temperature, and the results were evaluated according to the following criteria: ◎: 5% weight loss temperature of 300°C or higher; ○: 5% weight loss temperature of 250°C or higher but less than 300°C; ×: 5% weight loss temperature less than 250°C.

[0098] (4) Laser Lift-Off Peelability (LLO Peelability) A 5 cm square piece of quartz glass was heated and bonded at 70°C so that the release layer side of the electronic component temporary fixing member was in contact with the quartz glass. A glass plate was then bonded to the adhesive layer side of the electronic component temporary fixing member, and in Examples 1, 2, 3, 7, and 8 and Comparative Examples 1, 2, and 5, the member was heated at 150°C for 1 hour for a curing treatment. A laser (Nd-YAG) was then irradiated from the quartz glass surface to perform laser lift-off (LLO). The LLO conditions were a wavelength of 355 nm, an output of 600 mW, a frequency of 10 kHz, and an irradiation diameter of 20 μmφ. After LLO, whether the quartz glass had been peeled at the interface between the quartz glass and the release layer and whether any residue of the release layer remained on the quartz glass were determined visually and microscopically, and evaluated according to the following criteria. ◎: The quartz glass is peeled off at the interface between the quartz glass and the release layer, and there is no residue of the release layer on the quartz glass. ◯: The quartz glass is peeled off at the interface between the quartz glass and the release layer, but there is some residue of the release layer on part of the quartz glass. ×: The quartz glass is not peeled off at the interface between the quartz glass and the release layer, and there is residue of the release layer all over the quartz glass.

[0099] The components and evaluation results of the examples and comparative examples are shown in Table 1 below.

[0100]

[0101] As shown in Table 1 above, the electronic component temporary fixing members of Examples 1 to 8, in which the area ratio of the filler in the cross section in the thickness direction of the release layer was 8.0% or more and 92% or less, had excellent LLO release performance, the support was peeled off at the interface between the support and the release layer, and no residue of the release layer was left on the support.

[0102] Furthermore, as shown in Table 1 above, in the electronic component temporary fixing members of Examples 1 to 8, in which the area ratio of the filler in the cross section in the thickness direction of the release layer was 8.0% or more and 92% or less, the parallel ray transmittance of the release layer at a light wavelength of 380 nm was 60% or less, and the laser light absorption characteristics were excellent.

[0103] Furthermore, the electronic component temporary fixing members of Examples 1 to 8 not only had excellent LLO peeling performance, but also had high 5% weight loss temperatures of the release layers, and the release layers had excellent heat resistance. Furthermore, the electronic component temporary fixing members of Examples 1 to 6, which used polyimide for the core material, and Example 8, which used epoxy resin for the core material, had high 5% weight loss temperatures of the entire electronic component temporary fixing member and the core material, and the entire electronic component temporary fixing member and the core material had excellent heat resistance. Therefore, it was found that the heat-resistant electronic component temporary fixing member could maintain the peeling performance of the release layer from the support even when exposed to a high-temperature environment for a long period of time.

[0104] In the temporary electronic component fixing members of Examples 1 to 8, the filler content in the release layer was adjusted to 13% by mass or more and 69% by mass or less.

[0105] On the other hand, as shown in Table 1 above, in the members for temporary fixing electronic components of Comparative Examples 1 to 5, in which the area ratio of the filler in the cross section in the thickness direction of the release layer was 7% or less, excellent LLO release performance could not be obtained, the support was not released smoothly at the interface between the support and the release layer, and residue of the release layer remained on the support.

[0106] Furthermore, as shown in Table 1, in the electronic component temporary fixing members of Comparative Examples 1 to 5, in which the area ratio of the filler in the cross section in the thickness direction of the release layer was 7% or less, the parallel ray transmittance of the release layer at a light wavelength of 380 nm was 65% or more, and laser light absorption characteristics were not obtained. Furthermore, in Comparative Example 5, in which polyethylene terephthalate was used for the core material, the 5% weight loss temperature of the entire electronic component temporary fixing member and the core material was low, and the heat resistance of the entire electronic component temporary fixing member and the core material was poor.

Claims

1. A member for temporarily fixing electronic components, comprising a core material, a release layer provided on a first surface of the core material, and an adhesive layer provided on a second surface of the core material opposite the first surface, wherein the release layer contains a filler, and the area ratio of the filler in a cross section of the release layer perpendicular to the first surface is 8.0% or more and 92% or less.

2. A member for temporarily fixing an electronic component according to claim 1, wherein the release layer has a portion where the transmittance of light with a wavelength of 380 nm in a direction perpendicular to the first surface is 60% or less.

3. A member for temporarily fixing electronic components according to claim 1 or 2, wherein the content of the filler in the release layer is 10% by mass or more and 80% by mass or less.

4. A member for temporarily fixing electronic components according to claim 1 or 2, wherein the release layer contains a resin that is an adhesive component or a pressure-sensitive adhesive component, and contains 10 parts by mass or more and 300 parts by mass or less of the filler per 100 parts by mass (solid content) of the resin.

5. A member for temporarily fixing electronic components according to claim 1 or 2, wherein the particle diameter (D50) of the filler at a cumulative volume percentage of 50% by volume is 0.1 μm or more and 20 μm or less.

6. A member for temporarily fixing electronic components according to claim 1 or 2, wherein the filler contains silica.

7. A member for temporarily fixing electronic components according to claim 1 or 2, wherein the 5% weight loss temperature of the release layer is 250°C or higher.

8. A member for temporarily fixing electronic components according to claim 1 or 2, wherein the 5% weight loss temperature of said member for temporarily fixing electronic components is 250°C or higher.

9. The member for temporarily fixing electronic parts according to claim 1 or 2, wherein the core material is made of a polyimide resin or an epoxy resin.

10. A member for temporarily fixing electronic components according to claim 1 or 2, wherein the thickness of the release layer is 1.2 times or more the particle diameter (D90) of the filler at a cumulative volume percentage of 90% by volume.

11. The member for temporarily fixing electronic components according to claim 1 or 2, which is in the form of a tape.

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