Release film and electronic component device manufacturing method

Abstract

To provide a release film excellent in followability to an adherend surface, and a method for manufacturing an electronic component device using the release film.SOLUTION: A release film having an elongation percentage of 500% or more at 170°C.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a release film and an electronic component device. [Background technology]

[0002] In recent years, as electronic devices, especially mobile phones, have become thinner, there has been a demand for even thinner electronic components such as semiconductor elements. Furthermore, from the perspective of improving heat dissipation, there has been an increasing trend toward exposed die molding, which exposes part of the surface of an electronic component, instead of overmolding, which covers the entire electronic component with encapsulating resin.

[0003] When sealing electronic components so that a portion of the electronic component is exposed, it is necessary to prevent leakage of the sealing material onto the exposed portion of the electronic component (flash burrs).To address this issue, sealing is performed with a film with releasability (mold release film) attached to the exposed portion of the electronic component, and then the release film is peeled off to expose the surface of the electronic component. As such a release film, for example, Japanese Patent Application Laid-Open No. 2006-49850 describes a laminated film in which a film made of a fluororesin is laminated on at least one side of a base film made of a stretched polyester resin film. Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, the shapes of the adherend surfaces of release films have tended to become more complex, and there is a demand for improved conformability of release films to adherend surfaces (i.e., the ability to deform to fit the shape of the adherend surface).For example, there is a demand for the development of release films suitable for exposing terminals in the technology (thick film sealing) in which multiple semiconductor packages are mounted on a substrate and then sealed all at once.

[0005] In view of the above circumstances, an object of one aspect of the present disclosure is to provide a release film that has excellent conformability to an adherend surface.An object of another aspect of the present disclosure is to provide a method for manufacturing an electronic component device using this release film. [Means for solving the problem]

[0006] The means for solving the above problems include the following embodiments. <1> A release film with an elongation rate of 500% or more at 170°C. <2> The elastic modulus at 170°C is 65 MPa or more. <1> The release film according to claim 1. <3> The tack strength of the adherend surface at 23°C is 0.1 gf or more. <1> or <2> The release film according to claim 1. <4> It comprises a substrate layer and a release layer. <1> ~ <3> 10. The release film according to claim 1, wherein <5> The substrate layer comprises polybutylene terephthalate. <4> The release film according to claim 1. <6> The release layer contains an adhesive. <4> or <5> The release film according to claim 1. <7> The thickness of the release layer is 1 μm or more. <4> ~ <6> 10. The release film according to claim 1, wherein <8> For temporarily protecting at least a portion of the surface of an object, <1> ~ <7> 10. The release film according to claim 1, wherein <9> For exposed molding, <1> ~ <8> 10. The release film according to claim 1, wherein <10> <1> ~ <9> a step of sealing the periphery of an electronic component with the release film according to any one of the above items in contact with at least a portion of the surface of the electronic component; and a step of peeling the release film from the electronic component. [Effects of the Invention]

[0007] According to one aspect of the present disclosure, there is provided a release film having excellent conformability to a surface to be adhered. According to another aspect of the present disclosure, there is provided a method for manufacturing an electronic component device using the release film. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a plan view showing the shape of a test piece used to measure the elongation and elastic modulus of a release film. [Figure 2] FIG. 2 is a cross-sectional view schematically illustrating the configuration of a release film. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments for carrying out the present disclosure will be described in detail. However, the present disclosure is not limited to the following embodiments. In the following embodiments, components (including element steps, etc.) are not essential unless otherwise specified. The same applies to numerical values ​​and their ranges, and do not limit the present disclosure.

[0010] In this specification, the term "process" includes not only a process that is independent of other processes, but also a process that cannot be clearly distinguished from other processes as long as the purpose of the process is achieved. In this specification, numerical ranges indicated using "to" include the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In the present specification, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range. In addition, in the present specification, the upper or lower limit of a numerical range may be replaced with a value shown in the examples. In this specification, the content or amount of each component in a composition means, unless otherwise specified, the total content or amount of the multiple substances present in the composition when multiple substances corresponding to each component are present in the composition. In this specification, the particle size of each component in a composition means the value for a mixture of the multiple types of particles present in the composition, unless otherwise specified, when multiple types of particles corresponding to each component are present in the composition. In this specification, the term "layer" includes cases where the layer is formed over the entire area when the area in which the layer exists is observed, as well as cases where the layer is formed over only a part of the area. In this specification, the thickness of the release film or each layer constituting the release film can be measured by a known method. For example, it may be measured using a dial gauge or the like, or it may be measured from a cross-sectional image of the release film. Alternatively, the material constituting the layer may be removed using a solvent or the like, and the thickness may be calculated from the mass before and after removal, the density of the material, the area of ​​the layer, etc. If the layer thickness is not constant, the arithmetic average of values ​​measured at any five points is taken as the layer thickness. In this specification, "(meth)acrylic" means either or both of acrylic and methacrylic, and "(meth)acrylate" means either or both of acrylate and methacrylate. When embodiments of the present disclosure are described with reference to the drawings, the configuration of the embodiment is not limited to the configuration shown in the drawings. Furthermore, the sizes of the components in each drawing are conceptual, and the relative size relationships between the components are not limited to these.

[0011] <Release film> The release film of the present disclosure is a release film having an elongation rate at 170°C of 500% or more.

[0012] The release film has an elongation percentage of 500% or more at 170°C. Therefore, it has excellent elongation under typical temperature conditions in which the step of attaching the release film to the adherend surface is carried out, and exhibits excellent conformability to the adherend surface. Therefore, even when the adherend surface has a complex shape, for example, it can effectively prevent the sealant from penetrating into the area where the release film is attached.

[0013] The elongation percentage of the release film at 170° C. is 500% or more, preferably 550% or more, more preferably 600% or more, and even more preferably 700% or more. From the viewpoint of ease of peeling, the elongation percentage of the release film at 170°C may be 1300% or less, 1200% or less, 1000% or less, or 800% or less.

[0014] The release film preferably has a modulus of elasticity at 170°C of 65 MPa or more, more preferably 70 MPa or more, and even more preferably 75 MPa or more. When the modulus of elasticity of the release film at 170° C. is 65 MPa or more, the release film is appropriately hard and has good workability when being attached to the surface to be adhered. From the viewpoint of conformability to the adherend surface, the modulus of elasticity of the release film at 170° C. may be 150 MPa or less, 120 MPa or less, or 100 MPa or less.

[0015] The release film may have an elongation at 150°C of 500% or more, 550% or more, or 700% or more. When the elongation percentage of the release film at 150°C is 500% or more, the release film exhibits excellent adhesion even when it is attached to the surface to be adhered at a low temperature. From the viewpoint of ease of peeling, the elongation percentage of the release film at 150°C may be 1300% or less, 1200% or less, 1000% or less, or 800% or less.

[0016] The release film may have a modulus of elasticity at 150°C of 65 MPa or more, 70 MPa or more, or 75 MPa or more. When the release film has an elastic modulus of 65 MPa or more at 150°C, the workability is good even when the release film is attached to the surface to be adhered is carried out at low temperatures. From the viewpoint of conformability to the adherend surface, the modulus of elasticity of the release film at 150° C. may be 150 MPa or less, 120 MPa or less, or 100 MPa or less.

[0017] In the present disclosure, the elongation (%) of a release film is measured as follows. First, a test piece (length unit: mm) with the shape shown in Figure 1 is prepared using a release film. The shape of the test piece is not limited to the shape shown in Figure 1, as long as it has a width of 10 mm and a portion that can ensure the distance between the chucks. The tensile test is performed by gripping both ends of the test piece with the gripping tools (chucks) of the tensile testing machine. The test piece is gripped at a position where the width of the test piece is 10 mm, and the distance between the chucks is 15 mm. The measurement is performed under specified temperature conditions, and the tensile speed is 500 mm / min. The elongation percentage is calculated using the following formula from the chuck distance A (15 mm) of the test piece before the tensile test and the chuck distance B when the test piece is broken.

[0018]

number

[0019] To measure the elongation of the release film, for example, a Tensilon tensile tester RTA-100 manufactured by Orientec Co., Ltd., a Tensilon universal tester RTG-1210 manufactured by A&D Co., Ltd., or a similar tester having a clamp is used.

[0020] The elastic modulus (MPa) of the release film is calculated from the slope of the tangent line in the stress-strain diagram by pulling the test piece in the same manner as in the measurement of the elongation percentage. Specifically, the cross-sectional area (cm 2 ) is calculated using the following formula:

[0021]

number

[0022] From the viewpoint of adhesion to the adherend surface, the tack strength of the adherend surface of the release film at 23°C is preferably 0.1 gf or more, more preferably 0.2 gf or more, and even more preferably 0.5 gf or more.

[0023] From the viewpoint of releasability from the adherend surface, the tack strength of the adherend surface of the release film at 23°C is preferably 40 gf or less, more preferably 35 gf or less, and even more preferably 30 gf or less.

[0024] In the present disclosure, the tack force (gf) of a release film is measured using a tack tester (for example, manufactured by Rhesca) and a probe with a diameter of 5 mm under the conditions of 23°C, a pre-measurement load of 10 gf, a pre-measurement load time of 1 second, and a measurement rise speed of 120 mm / min.

[0025] The release film may have a base layer and a release layer, and may further have a conductive layer.

[0026] An example of the configuration of a release film having a substrate layer, a release layer, and a conductive layer is shown schematically in Figure 2. The release film 40 shown in Figure 2 includes a substrate layer 10, a release layer 20, and a conductive layer 30 disposed between the substrate layer 10 and the release layer 20.

[0027] The release film has a base layer, which provides the release film with the necessary strength, and by appropriately selecting the material, the physical properties such as elongation and elastic modulus can be adjusted. By having a release layer on the release film, the release film can be easily peeled off from the adherend surface. By providing the release film with a conductive layer, discharge when the release film is peeled off is suppressed, and electrostatic damage to electronic components is effectively suppressed.

[0028] The total thickness of the release film is not particularly limited and can be set according to the desired physical properties (elongation, elastic modulus, etc.) For example, it may be 30 μm to 300 μm, 35 μm to 250 μm, or 40 μm to 200 μm.

[0029] (base material layer) The material of the substrate layer is not particularly limited as long as the release film using it has an elongation of 500% or more at 170°C. Examples of the resin include polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyimide, polyamide, polyester ether, polyamideimide, fluorine-containing resins, and thermoplastic elastomers.

[0030] From the viewpoint of ensuring the elongation percentage at 170°C, the substrate layer preferably contains polybutylene terephthalate. The base layer may contain only polybutylene terephthalate as a resin, or may contain polybutylene terephthalate and a resin other than polybutylene terephthalate. For example, the base layer may contain polybutylene terephthalate and polyethylene terephthalate. When the base layer contains polybutylene terephthalate and polyethylene terephthalate, it is expected to have the effect of increasing the elastic modulus while maintaining a high elongation percentage, for example.

[0031] When the base layer contains polybutylene terephthalate and a resin other than polybutylene terephthalate, the proportion of polybutylene terephthalate may be 50% by mass or more, 60% by mass or more, 70% by mass or more, or 80% by mass or more of the total resin, and may be 99% by mass or less, or 95% by mass or less of the total resin.

[0032] From the viewpoint of ensuring a sufficient elongation percentage at 170°C, the substrate layer is preferably unstretched (not subjected to a stretching treatment).

[0033] The thickness of the base layer is not particularly limited, but is preferably 10 μm or more, more preferably 20 μm or more, and even more preferably 30 μm or more. When the thickness of the base layer is 10 μm or more, the release sheet tends to be less likely to tear and has excellent handleability. The thickness of the substrate layer is preferably 300 μm or less, more preferably 200 μm or less, and even more preferably 100 μm or less. When the thickness of the substrate layer is 300 μm or less, sufficient conformability to the adherend surface tends to be obtained.

[0034] The substrate layer may be composed of only one layer or two or more layers. Methods for obtaining a substrate layer composed of two or more layers include a method in which the materials for each layer are co-extruded, a method in which two or more films are laminated, and the like.

[0035] When the release film includes a conductive layer, the surface of the base layer on which the conductive layer is provided may be subjected to a treatment to improve adhesion to the conductive layer. Examples of the treatment method include surface treatment such as corona treatment and plasma treatment, and application of a primer.

[0036] If necessary, a backing treatment agent may be applied to the back surface of the substrate layer (the surface opposite to the side to be attached to the adherend surface) to adjust the unwinding property of the release film from the roll. Examples of backing treatment agents include silicone resins, fluorine-containing resins, polyvinyl alcohol, and resins having alkyl groups. If necessary, these backing treatment agents may be modified. One type of backing treatment agent may be used alone, or two or more types may be used in combination.

[0037] (Release layer) The material of the release layer is not particularly limited and can be selected depending on the desired properties of the release film (adhesion to the adherend surface, releasability, etc.). From the viewpoint of adhesion to the adherend surface, the release layer preferably has adhesiveness. One method for imparting adhesiveness to the release layer is to incorporate an adhesive agent into the release layer.

[0038] The type of adhesive is not particularly limited and can be selected in consideration of adhesiveness, releasability, heat resistance, etc. Specifically, acrylic adhesives, silicone adhesives, and urethane adhesives are preferred, with acrylic adhesives being more preferred. The adhesive contained in the release layer may be of one type or two or more types.

[0039] The acrylic adhesive is preferably a copolymer (hereinafter also referred to as an acrylic copolymer) obtained by copolymerizing a monomer having a low glass transition temperature (Tg) (for example, −20° C. or lower) such as butyl acrylate, ethyl acrylate, or 2-ethylhexyl acrylate as the main monomer with a monomer having a functional group such as (meth)acrylic acid, hydroxyethyl (meth)acrylate, hydroxyethyl (meth)acrylate, (meth)acrylamide, or (meth)acrylonitrile. The above “glass transition temperature” refers to the glass transition temperature of a homopolymer obtained using the corresponding monomer.

[0040] The acrylic copolymer may be a cross-linked acrylic copolymer. The cross-linked acrylic copolymer can be synthesized by cross-linking the monomers that are the raw materials for the acrylic copolymer using a cross-linking agent. Examples of cross-linking agents used in synthesizing the cross-linked acrylic copolymer include known cross-linking agents such as isocyanate compounds, melamine compounds, and epoxy compounds. In addition, in order to form a network structure that spreads gently in the acrylic pressure-sensitive adhesive, the cross-linking agent is preferably a multifunctional cross-linking agent such as a trifunctional or tetrafunctional cross-linking agent.

[0041] The release layer may contain, as needed, an anchoring improver, a crosslinking accelerator, a filler, a colorant, etc. For example, when the release layer contains a filler, the outer surface of the release layer (the surface opposite to the conductive layer) is roughened, thereby providing an effect of improving the releasability from electronic components.

[0042] The filler material is not particularly limited and may be an organic substance such as a resin, an inorganic substance such as a metal or a metal oxide, or a combination of an organic substance and an inorganic substance. The release layer may contain one or more types of filler. The volume average particle diameter of the filler is not particularly limited. For example, it may be selected from the range of 1 μm to 20 μm. In this specification, the volume average particle diameter of the filler is the particle diameter (D50) at which the cumulative total from the small diameter side reaches 50% in the volume-based particle size distribution measured by laser diffraction.

[0043] From the viewpoint of affinity with the adhesive contained in the release layer, the filler is preferably resin particles. Examples of resins constituting the resin particles include acrylic resin, olefin resin, styrene resin, acrylonitrile resin, silicone resin, etc. From the viewpoint of suppressing residues on the surface of the semiconductor package after molding, acrylic resin is preferred.

[0044] The thickness of the release layer is not particularly limited, but is preferably 0.1 μm or more, more preferably 1 μm or more. When the thickness of the release layer is 0.1 μm or more, sufficient adhesive strength to electronic components is obtained, and penetration of the sealing material is effectively suppressed. The thickness of the release layer may be 100 μm or less, 50 μm or less, or 10 μm or less. When the thickness of the release layer is 100 μm or less, heat shrinkage stress is less likely to occur during thermal curing of the release layer, and the flatness of the release film is easily maintained. Furthermore, when the release film has a conductive layer, the distance from the conductive layer to the surface of the release layer is not too far, so that the surface resistivity is maintained low, and electrostatic damage to electronic components is effectively suppressed. Taking into consideration the ease of forming the release layer (such as coating properties), ensuring adhesive strength, ensuring antistatic properties, etc., it is more preferable that the thickness of the release layer is 3 μm to 50 μm.

[0045] (Conductive layer) The conductive layer is not particularly limited in configuration as long as it can increase the conductivity of the release film and suppress charging. For example, it may be a layer containing a conductive material such as an antistatic agent, a conductive polymer material, or a metal.

[0046] Examples of antistatic agents contained in the conductive layer include cationic antistatic agents having cationic groups such as quaternary ammonium salts, pyridinium salts, and primary to tertiary amino groups; anionic antistatic agents having anionic groups such as sulfonate groups, sulfate groups, and phosphate groups; amphoteric antistatic agents such as amino acid-based and amino acid sulfate-based; nonionic antistatic agents having nonionic groups such as amino alcohol-based, glycerin-based, and polyethylene glycol-based; and polymeric antistatic agents obtained by increasing the molecular weight of these antistatic agents. The antistatic agent may be a combination of a main agent and an auxiliary agent (such as a curing agent). Examples of the conductive polymer material contained in the conductive layer include polymer compounds having polythiophene, polyaniline, polypyrrole, polyacetylene, or the like in the skeleton. Examples of metals include aluminum, copper, gold, chromium, and tin, with aluminum being preferred from the viewpoint of availability.

[0047] The method for forming the conductive layer is not particularly limited, and examples thereof include a method of laminating a metal foil or the like on one side of a film that will serve as a base layer, and a method of applying a material for the conductive layer to one side of a film that will serve as a base layer by coating, vapor deposition, or the like.

[0048] The thickness of the conductive layer is not particularly limited as long as it provides a sufficient antistatic effect for the release film, and may be, for example, within the range of 0.01 μm to 1 μm.

[0049] The release film of the present disclosure can be used for various purposes. For example, it can be used to temporarily protect at least a part of the surface of an object. Since the release film of the present disclosure has excellent conformability to the adherend surface, when processing is performed around the area where the release film is attached, the area can be effectively protected from the influence of the processing. In the present disclosure, "temporarily protect" refers to protecting the part of the surface of an object to which the release film is attached from the time the release film is attached to at least a part of the surface until the time the release film is peeled off.

[0050] There are no particular limitations on the type of processing that can be performed on the periphery of the region where the release film is attached, and examples include sealing with a sealant, roughening treatment, painting treatment, water-repellent treatment, and antistatic treatment. The release film may be one used in exposure molding.

[0051] <Electronic component device manufacturing method> The method for manufacturing an electronic component device of the present disclosure includes a step of sealing the periphery of the electronic component with the above-mentioned release film in contact with at least a portion of the surface of the electronic component, and a step of peeling the release film from the electronic component.

[0052] As described above, the release film of the present disclosure has excellent conformability to the adherend surface, which effectively prevents the encapsulant from penetrating into the exposed portion of the electronic component surface that appears when the release film is peeled off.

[0053] The type of electronic component used in the above method is not particularly limited, and examples thereof include semiconductor elements, capacitors, terminals, etc. In the above method, the type of material (sealant) used to seal the periphery of the electronic component is not particularly limited, and examples thereof include resin compositions containing epoxy resins, acrylic resins, etc. [Example]

[0054] The release film of the present disclosure will be described below based on examples, although the present disclosure is not limited to the following examples.

[0055] Example 1 As the substrate layer, a 50 μm thick unstretched polybutylene terephthalate film that had been subjected to a corona treatment on one side was prepared. An antistatic agent described below diluted to 2.5% by mass with a mixed solvent (water / isopropyl alcohol = 1 / 1 (mass ratio)) was applied to the corona-treated surface of the substrate layer, and heated at 100°C for 1 minute to form a conductive layer. On the formed conductive layer, the composition for forming a release layer described below was applied so that the thickness of the release layer was 5 μm, and the layer was heated at 100° C. for 1 minute to form a release layer, thereby producing a release film.

[0056] The antistatic agent used in producing the release film was a mixture of the following component A (100 parts by mass) and component B (25 parts by mass). Component A: Cationic antistatic agent, an acrylic copolymer containing a quaternary ammonium salt, product name "Bondip PA-100 Main Agent", Konishi Co., Ltd. Component B: Epoxy hardener, product name "Bondip PA-100 Hardener", Konishi Co., Ltd.

[0057] The composition for forming the release layer used to prepare the release film was a mixture of 100 parts by weight of the adhesive described below, 20 parts by weight of a crosslinking agent, 5 parts by weight of a filler, and 34 parts by weight of a mixed solvent (toluene / methyl ethyl ketone = 8:2 (mass ratio)). Adhesive: Acrylic adhesive, product name "FS-1208", solid content: 45% by mass, Lion Specialty Chemicals Co., Ltd., mixture of multiple methacrylate ester monomers Crosslinking agent: Product name "Duranate E405-80T", solid content: 80% by mass, Asahi Kasei Chemicals Corporation, polyisocyanate crosslinking agent (hexamethylene diisocyanate crosslinking agent (HMDI)), number of isocyanate groups per molecule: 2 Filler: Cross-linked acrylic medium-dispersion particles, product name "MX-500", volume average particle size: 5 μm, Soken Chemical & Engineering Co., Ltd.

[0058] <Example 2> As the substrate layer, a 50 μm thick unstretched polybutylene terephthalate / polyethylene terephthalate film that had been subjected to a corona treatment on one side was prepared. The unstretched polybutylene terephthalate / polyethylene terephthalate film used contained 90% by mass of polybutylene terephthalate and 10% by mass of polyethylene terephthalate. A release film was produced in the same manner as in Example 1, except that the above-mentioned base material layer was used.

[0059] Example 3 As the substrate layer, a 100 μm thick unstretched polybutylene terephthalate film that had been subjected to a corona treatment on one side was prepared. The same antistatic agent as used in Example 1 diluted to 2.5% by mass with a mixed solvent (water / isopropyl alcohol = 1 / 1 (mass ratio)) was applied to the corona-treated surface of the substrate layer, and the coating was heated at 100°C for 1 minute to form a conductive layer. The same release layer forming composition used in Example 1 was applied onto the formed conductive layer so that the thickness of the release layer was 10 μm, and the layer was heated at 100°C for 1 minute to form a release layer, thereby producing a release film.

[0060] <Comparative Example 1> A release film was produced in the same manner as in Example 1, except that a 50 μm thick stretched polybutylene terephthalate film was used as the base layer instead of a 50 μm thick unstretched polybutylene terephthalate film.

[0061] <Evaluation test> The prepared release films were subjected to the following evaluation tests.

[0062] (Measurement of elongation and elastic modulus) A test piece as shown in Figure 1 was prepared using a release film and placed in a chamber heated to 170°C. After 1 minute had passed, the above-mentioned tensile test was carried out in the chamber, and the elongation and elastic modulus at 170°C were measured. In Examples 1 and 2 and Comparative Example 2, a "Tensilon Tensile Tester RTA-100" manufactured by Orientec Co., Ltd. was used as the tensile tester. In Example 3, the tensile tester used was a Tensilon Universal Testing Machine RTG-1210 manufactured by A&D Co., Ltd.

[0063] (Measurement of tackiness) The tack strength of the surface of the release layer of the release film at 23° C. was measured by the method described above.

[0064] (mold followability) A release film was attached to the upper die of a 1 mm deep transfer mold, and after vacuum fixing, the mold was clamped and the encapsulant was transfer molded. The mold temperature was 170°C and the molding pressure was 6.86 MPa (70 kgf / cm). 2 ) and the molding time was 300 seconds. Mold tracking ability was evaluated as OK if vacuum suction was possible and the release sheet could follow, but NG if tracking was insufficient and vacuum suction leakage occurred.

[0065] (Heat resistance) Resin films for the base layer were cut to a desired size and heated for 5 minutes on a SUS (stainless steel) hot plate heated to 170°C, and the adhesion to the hot plate was evaluated. If the film did not stick, it was rated as OK, and if it did stick, it was rated as NG. The results are shown in Table 1.

[0066] [Table 1]

[0067] As shown in the results in Table 1, the release films of Examples 1 to 3, which have an elongation rate of 500% or more at 170°C, have better conformability to the adherend surface than the release film of Comparative Example 1, which has an elongation rate of less than 500% at 170°C.

[0068] The disclosure of International Application No. 2020 / 031272 is incorporated herein by reference in its entirety. All publications, patent applications, and technical standards mentioned in this specification are incorporated by reference into this specification to the same extent as if each individual publication, patent application, or technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. A release film having an elongation rate of 500% or more at 170°C.

2. 2. The release film according to claim 1, having an elastic modulus at 170°C of 65 MPa or more.

3. 3. The release film according to claim 1, wherein the surface on the adherend side has a tack strength of 0.1 gf or more at 23°C.

4. The release film according to any one of claims 1 to 3, comprising a substrate layer and a release layer.

5. The release film according to claim 4 , wherein the substrate layer comprises polybutylene terephthalate.

6. The release film according to claim 4 or claim 5, wherein the release layer comprises an adhesive.

7. The release film according to any one of claims 4 to 6, wherein the release layer has a thickness of 1 µm or more.

8. The release film according to any one of claims 1 to 7, for temporarily protecting at least a part of the surface of an object.

9. The release film according to any one of claims 1 to 8, which is for exposure molding.

10. 10. A method for manufacturing an electronic component device, comprising: a step of sealing the periphery of an electronic component with the release film according to any one of claims 1 to 9 in contact with at least a portion of the surface of the electronic component; and a step of peeling the release film from the electronic component.

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