Release film and method for manufacturing electronic component device

Abstract

To provide a release film having excellent anti-static performance.SOLUTION: Provided is a release film that includes, in this order, a base layer, a conductive layer, and a release layer. The release layer contains polyacrylonitrile particles.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a release film and a method for manufacturing a semiconductor package.

Background Art

[0002] In recent years, as electronic devices, particularly mobile phones, have become thinner, there has been a demand for further thinning of electronic components such as semiconductor elements. Also, from the perspective of improving heat dissipation, instead of overmolding, which covers the entire electronic component with a sealing resin, there is an increasing number of cases where exposed die molding, which exposes a part of the surface of the electronic component, is adopted.

[0003] When sealing an electronic component so that a part of the electronic component is in an exposed state, it is necessary to prevent leakage (flash burr) of the sealing material to the exposed part of the electronic component. Therefore, sealing is performed with a film having releasability (release film) attached to the part to be exposed 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, Patent Document 1 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.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When the release film is made of a material that is prone to charging, static electricity may be generated when the release film comes into contact with the electronic component or when the release film is peeled off from the electronic component, which may cause electrostatic breakdown of the electronic component. In recent years, with the high integration of semiconductor devices, the process node has been miniaturized, and the risk of electrostatic breakdown of electronic components is increasing.

[0006] In view of the above circumstances, one aspect of the present disclosure aims to provide a release film with excellent antistatic performance. Another aspect of the present disclosure aims to provide a method for manufacturing a semiconductor package using this release film.

Means for Solving the Problems

[0007] The means for solving the above problems include the following embodiments. <1>A release film having a base material layer, a conductive layer, and a release layer in this order, wherein the release layer contains polyacrylonitrile particles. <2>The release film according to <1>, wherein the ratio (A / B) of the average particle diameter A of the polyacrylonitrile particles to the thickness B of the release layer is greater than 0.7. <3>The release film according to <1> or <2>, wherein the content of the polyacrylonitrile particles is 10% by mass or more of the entire release layer. <4>The release film according to any one of <1> to <3>, wherein the release layer contains an adhesive. <5>The release film according to any one of <1> to <4>, for temporarily protecting at least a part of the surface of an object. <6>The release film according to any one of <1> to <5>, for exposed molding. <7>A method for manufacturing an electronic component device, comprising a step of sealing the periphery of an electronic component in a state where the release film according to any one of <1> to <6> is in contact with at least a part of the surface of the electronic component, and a step of peeling the release film from the electronic component.

Advantages of the Invention

[0008] According to one aspect of the present disclosure, a release film having excellent antistatic performance is provided. According to another aspect of the present disclosure, a method for manufacturing an electronic component device using this release film is provided.

Brief Description of the Drawings

[0009]

Figure 1

Embodiments for Carrying Out the Invention

[0010] 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, the components thereof (including element steps, etc.) are not essential unless otherwise specified. The same applies to numerical values and ranges thereof, and they do not limit the present disclosure.

[0011] In this specification, the term "step" includes not only a step independent of other steps but also a step that cannot be clearly distinguished from other steps as long as the purpose of the step is achieved. In the numerical range indicated by "~" in this specification, the numerical values described before and after "~" are included as the minimum value and the maximum value, respectively. In the numerical ranges described step by step in this specification, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of the numerical range described in other step-by-step descriptions. Also, in the numerical ranges described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples. In this specification, the content or content rate of each component in the composition means the total content or content rate of the plurality of substances corresponding to each component in the composition, unless otherwise specified when there are a plurality of substances corresponding to each component in the composition. In this specification, the particle diameter of each component in the composition means a value for a mixture of the plurality of types of particles present in the composition, unless otherwise specified when there are a plurality of types of particles corresponding to each component in the composition. In this specification, the term "layer" includes not only the case where it is formed over the entire region where the layer exists, but also the case where it is formed only in a part of the region when observing the region where the layer exists. In this specification, the thickness of the release film or each layer constituting the release film can be measured by known methods. For example, it may be measured using a dial gauge or the like, or 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 may be calculated from the mass before and after removal, the density of the material, the area of the layer, etc. When the thickness of the layer is not constant, the arithmetic average value of the values measured at any five points is taken as the thickness of the layer. In this specification, "(meth)acryl" means either or both of acrylic and methacrylic, and "(meth)acrylate" means either or both of acrylate and methacrylate.

[0012] <Release film> The release film of the present disclosure has a base material layer, a conductive layer, and a release layer in this order, and the release layer contains polyacrylonitrile particles.

[0013] The release film having the above configuration exhibits excellent antistatic performance. Specifically, in addition to having a conductive layer between the base material layer and the release layer, the release layer contains polyacrylonitrile particles, thereby exhibiting excellent antistatic performance. The reason why the antistatic performance is improved by the release layer containing polyacrylonitrile particles is considered that the non-bonding electron pair of the nitrogen atom contained in the polyacrylonitrile particles imparts conductivity to the release layer.

[0014] An example of the configuration of the release film having a base material layer, a release layer, and a conductive layer is schematically shown in FIG. 1. The release film 40 shown in FIG. 1 includes a base material layer 10, a release layer 20, and a conductive layer 30 disposed between the base material layer 10 and the release layer 20.

[0015] Since the release film has a base material layer, the strength required for the release film is imparted, and by appropriately selecting the material thereof, physical properties such as elongation and elastic modulus can be adjusted. Since the release film has a release layer, the release film can be easily peeled from the adherend surface. Since the release film has a conductive layer, discharge during attachment or detachment of the release film is suppressed, and the occurrence of electrostatic breakdown of electronic components and the like is effectively suppressed.

[0016] The overall thickness of the release film is not particularly limited and can be set according to desired physical properties (elongation, elastic modulus, etc.). For example, it may be 30 μm to 300 μm, may be 35 μm to 250 μm, or may be 40 μm to 200 μm.

[0017] (Base material layer) The material of the base material layer is not particularly limited. For example, resins such as polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyimide, polyamide, polyester ether, polyamideimide, fluorine-containing resin, and thermoplastic elastomer can be mentioned. The resin contained in the base material layer may be only one kind or two or more kinds.

[0018] From the viewpoint of film handleability, it is preferable that the release film has a certain degree of stiffness. For this reason, it is preferable that the base material layer contains polyester, and it is more preferable that it contains polyethylene terephthalate.

[0019] The base material layer may or may not be subjected to a stretching treatment. When the stretching treatment is performed, the release film tends to have excellent strength, and when the stretching treatment is not performed, the release film tends to have excellent stretchability.

[0020] The thickness of the base material layer is not particularly limited, and it 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 material layer is 10 μm or more, the release sheet is difficult to break and has excellent handleability. The thickness of the base material layer is preferably 300 μm or less, more preferably 200 μm or less, and even more preferably 100 μm. When the thickness of the base material layer is 300 μm or less, sufficient followability (the property of deforming according to the shape of the adherend surface) to the adherend surface can be obtained.

[0021] The base material layer may be composed of only one layer or two or more layers. Examples of methods for obtaining a base material layer composed of two or more layers include a method of extruding the materials of each layer by a co-extrusion method and a method of laminating two or more films.

[0022] When the release film contains a conductive layer, a treatment for improving the adhesion to the conductive layer may be applied to the surface of the base material layer on the side where the conductive layer is provided. Examples of the treatment method include surface treatments such as corona treatment and plasma treatment, and application of an undercoat agent (primer).

[0023] If necessary, a back surface treatment agent for adjusting the unwindability from the roll of the release film may be applied to the back surface of the base material layer (the surface opposite to the side to be attached to the adherend surface). Examples of the back surface treatment agent include silicone resin, fluorine-containing resin, polyvinyl alcohol, and resin having an alkyl group. If necessary, these back surface treatment agents may be subjected to a modification treatment. The back surface treatment agent may be used alone or in combination of two or more.

[0024] (Release layer) If the release layer contains polyacrylonitrile particles, its material is not particularly limited. From the viewpoint of adhesion to the adherend surface, the release layer preferably has adhesiveness. Examples of the method for imparting adhesiveness to the release layer include a method of containing an adhesive in the release layer.

[0025] The type of the adhesive is not particularly limited and can be selected in consideration of adhesiveness, release property, heat resistance, etc. Specifically, an acrylic-based adhesive, a silicone-based adhesive, and a urethane-based adhesive are preferable, and an acrylic-based adhesive is more preferable. The adhesive contained in the release layer may be only one type or two or more types.

[0026] The acrylic pressure-sensitive 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, 2-ethylhexyl acrylate, etc., which are the main monomers, with a monomer having a functional group such as (meth)acrylic acid, hydroxyethyl (meth)acrylate, hydroxyethyl (meth)acrylate, (meth)acrylamide, (meth)acrylonitrile, etc. The above "glass transition temperature" is the glass transition temperature of the homopolymer obtained using the corresponding monomer.

[0027] The acrylic copolymer may be a crosslinked acrylic copolymer. The crosslinked acrylic copolymer can be synthesized by crosslinking the monomers used as raw materials of the acrylic copolymer using a crosslinking agent. Examples of the crosslinking agent used in the synthesis of the crosslinked acrylic copolymer include known crosslinking agents such as isocyanate compounds, melamine compounds, and epoxy compounds. Further, in order to form a gently spreading network structure in the acrylic pressure-sensitive adhesive, the crosslinking agent is more preferably a polyfunctional crosslinking agent such as trifunctional or tetrafunctional.

[0028] The content of the polyacrylonitrile particles contained in the release layer is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more of the entire release layer. When the content of the polyacrylonitrile particles is 10% by mass or more of the entire release layer, the polyacrylonitrile particles tend to function sufficiently as a conductive path in the release layer, and sufficient antistatic performance can be obtained. From the viewpoint of suppressing the cohesive failure of the release layer and the generation of residues on the adherend surface, the content of the polyacrylonitrile particles is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less of the entire release layer.

[0029] From the viewpoint of imparting sufficient conductivity to the release layer, the ratio (A / B) of the average particle diameter A of the polyacrylonitrile particles to the thickness B of the release layer is preferably greater than 0.7, more preferably 0.75 or more, still more preferably 0.8 or more, still more preferably 0.9 or more, and still more preferably 0.95 or more. When the ratio (A / B) of the average particle diameter A of the polyacrylonitrile particles to the thickness B of the release layer is 0.75 or more, the polyacrylonitrile particles tend to function sufficiently as a conductive path and sufficient antistatic performance is obtained. From the viewpoint of suppressing the detachment of the polyacrylonitrile particles from the release layer, A / B is preferably 2.0 or less, and more preferably 1.7 or less.

[0030] The thickness B of the release layer is the thickness of the release layer containing polyacrylonitrile particles in the thickness direction of the release film. When the thickness is not constant, the cross-section obtained after cutting the release film is observed by SEM, and the arithmetic average value of the thicknesses at arbitrarily selected 5 locations is taken as the thickness B of the release layer.

[0031] Also, when the approximate resin composition is known by a known analysis method, the release layer is removed using a solvent such as methyl ethyl ketone as described in the examples, and the thickness B of the release layer can be calculated from the mass difference of the release film before and after removal, the specific gravity of the resin removed with the solvent, and the volume of the polyacrylonitrile particles remaining as insoluble matter.

[0032] The average particle diameter of the polyacrylonitrile particles may be, for example, in the range of 1 μm to 50 μm, may be in the range of 5 μm to 30 μm, or may be in the range of 7 μm to 20 μm.

[0033] In the present disclosure, the average particle diameter of the particles is the particle diameter (D50) when the cumulative from the small diameter side is 50% in the volume-based particle size distribution measured by the laser diffraction / scattering method.

[0034] The particle shape of the polyacrylonitrile particles is not particularly limited and may be spherical or non-spherical (flat, irregular, etc.). From the viewpoint of blending a sufficient amount into the release layer, the polyacrylonitrile particles are preferably non-spherical. For example, the average aspect ratio (major axis / minor axis) of the polyacrylonitrile particles may be 1.1 or more, may be 1.2 or more, or may be 1.5 or more. The average aspect ratio of the polyacrylonitrile particles may be 10 or less, may be 7 or less, or may be 5 or less. In the present disclosure, the average aspect ratio of the particles is taken as the arithmetic mean value of the aspect ratios of 100 arbitrarily selected particles.

[0035] The average particle diameter of the polyacrylonitrile particles contained in the release film can be measured by the following procedure. The release layer of the release film is removed using a solvent such as methyl ethyl ketone, and the polyacrylonitrile particles remaining as insoluble matter are analyzed in the volume-based particle size distribution measured by the laser diffraction / scattering method, and the particle diameter (D50) when the cumulative from the small diameter side reaches 50% is taken as the average particle diameter.

[0036] The release layer may contain only polyacrylonitrile particles or may contain polyacrylonitrile particles and particles other than polyacrylonitrile particles.

[0037] The material of the particles other than the polyacrylonitrile particles 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.

[0038] From the viewpoint of the affinity with the adhesive contained in the release layer, the particles other than the polyacrylonitrile particles are preferably resin particles. Examples of the resin constituting the resin particles include acrylic resins, olefin resins, styrene resins, silicone resins, etc. From the viewpoint of suppressing residues on the surface of the semiconductor package after molding, an acrylic resin is preferred.

[0039] The average particle diameter of particles other than polyacrylonitrile particles is not particularly limited. For example, it can be selected from the range of 1 μm to 20 μm.

[0040] When the release layer contains polyacrylonitrile particles and particles other than polyacrylonitrile particles, from the viewpoint of imparting sufficient conductivity to the release layer and suppressing the aggregation breakdown of the release layer, the proportion of polyacrylonitrile particles in the total particles is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more.

[0041] The release layer may contain, if necessary, components other than the adhesive and particles. For example, it may contain an anchoring improver, a crosslinking accelerator, a colorant, etc.

[0042] The thickness of the release layer is not particularly limited, and is preferably 0.1 μm or more, and more preferably 1 μm or more. When the thickness of the release layer is 0.1 μm or more, sufficient adhesive force to the electronic component can be obtained, and the intrusion of the encapsulant is effectively suppressed. The thickness of the release layer may be 100 μm or less, may be 50 μm or less, or may be 10 μm or less. When the thickness of the release layer is 100 μm or less, the thermal shrinkage stress during the thermosetting of the release layer is less likely to occur, and the flatness of the release film is easily maintained. Further, when the release film has a conductive layer, the distance from the conductive layer on the surface of the release layer is not too far and the surface resistivity is maintained low, and the electrostatic breakdown of the electronic component is effectively suppressed. Taking into comprehensive consideration the ease of forming the release layer (coatability, etc.), ensuring the adhesive force, ensuring the antistatic function, etc., the thickness of the release layer is more preferably 3 μm to 50 μm.

[0043] (Conductive layer) The configuration of the conductive layer is not particularly limited as long as it can enhance the conductivity of the release film and suppress charging. For example, it may be a layer containing an antistatic agent, a conductive polymer material, a conductive material such as a metal.

[0044] Examples of the antistatic agent contained in the conductive layer include quaternary ammonium salts, pyridinium salts, cationic antistatic agents having a cationic group such as primary to tertiary amino groups, anionic antistatic agents having an anionic group such as a sulfonate group, a sulfate ester group, and a phosphate ester group, amphoteric antistatic agents such as amino acid-based and amino acid sulfate ester-based, nonionic antistatic agents having a nonionic group such as amino alcohol-based, glycerin-based, and polyethylene glycol-based, and polymer-type antistatic agents obtained by polymerizing 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 a skeleton such as polythiophene, polyaniline, polypyrrole, and polyacetylene. Examples of the metal include aluminum, copper, gold, chromium, tin, etc., and aluminum is preferred from the viewpoint of availability.

[0045] The method for forming the conductive layer is not particularly limited. For example, there are a method of laminating a metal foil or the like on one side of a film serving as a base material layer, and a method of applying a material for the conductive layer on one side of a film serving as a base material layer by coating, vapor deposition, or the like.

[0046] The thickness of the conductive layer is not particularly limited as long as the antistatic effect of the release film can be sufficiently obtained. For example, it may be in the range of 0.01 μm to 1 μm.

[0047] The release film of the present disclosure can be used in various applications. 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 followability 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. In the present disclosure, "temporarily protect" means protecting the portion where the release film is attached from when the release film is attached to at least a part of the surface of an object until it is peeled off.

[0048] The type of processing performed on the periphery of the area where the release film is attached is not particularly limited. Specifically, examples include sealing with a sealing material, roughening treatment, painting treatment, water repellent treatment, antistatic treatment, and the like. The release film may be used for exposed molding.

[0049] <Method for manufacturing an electronic component device> The method for manufacturing an electronic component device according to the present disclosure includes a step of sealing the periphery of the electronic component in a state where the above-described release film is in contact with at least a part of the surface of the electronic component, and a step of peeling the release film from the electronic component.

[0050] As described above, the release film of the present disclosure has excellent antistatic performance. Therefore, the occurrence of electrostatic breakdown of the electronic component is effectively suppressed.

[0051] The type of electronic component used in the above method is not particularly limited. Examples include semiconductor elements, capacitors, terminals, and the like. The type of material (sealing material) for sealing the periphery of the electronic component in the above method is not particularly limited. Examples include resin compositions containing epoxy resins, acrylic resins, and the like.

Example

[0052] Hereinafter, the release film of the present disclosure will be described based on examples. However, the present disclosure is not limited to the following examples.

[0053] <Example 1> As a base material layer, a biaxially stretched polyethylene terephthalate film (trade name "S-38", manufactured by Unitika Ltd.) with a thickness of 38 μm and corona treatment on one side was prepared. On the corona-treated surface of the base material layer, the following antistatic agent diluted to 2.5% by mass with a mixed solvent (water / isopropyl alcohol = 1 / 1 (mass ratio)) was applied and heated at 100 ° C for 1 minute to form a conductive layer.

[0054] The antistatic agent used in the production of the release film is a mixture of the following Component A (100 parts by mass) and Component B (25 parts by mass).

[0055] Component A: A cationic antistatic agent which is an acrylic copolymer having a quaternary ammonium salt, trade name "Bondip PA-100 Main Agent", manufactured by Konishi Co., Ltd. Component B: An epoxy-based curing agent, trade name "Bondip PA-100 Curing Agent", manufactured by Konishi Co., Ltd.

[0056] On the formed conductive layer, the following release layer-forming composition was applied and heated at 100 °C for 1 minute to form a release layer, thereby producing a release film. The release layer-forming composition used in the production of the release film is a mixture of the following adhesive (100 parts by mass), crosslinking agent (10 parts by mass), resin particles A (25 parts by mass), and mixed solvent (toluene / methyl ethyl ketone = 8:2 (mass ratio)) 34 parts by mass.

[0057] Adhesive: An acrylic adhesive, trade name "B-3", manufactured by Lion Specialty Chemicals Co., Ltd., a mixture of multiple methacrylic acid ester monomers Crosslinking agent: A hexamethylene diisocyanate crosslinking agent, trade name "Coronate H-CL", manufactured by Nippon Polyurethane Industry Co., Ltd. Resin particles A: Polyacrylonitrile particles, trade name "Tuftic ASF-7", manufactured by Toyobo Co., Ltd., volume average particle diameter: 7 μm, irregular shape

[0058] <Example 2> A release film was produced in the same manner as in Example 1, except that the amount of resin particles A was changed to 30 parts by mass.

[0059] <Example 3> A release film was produced in the same manner as in Example 1, except that the amount of resin particles A was changed to 40 parts by mass.

[0060] <Example 4> A release film was produced in the same manner as in Example 1, except that the resin particles A were changed to the following resin particles B and the amount thereof was changed to 30 parts by mass. Resin particles B: Polyacrylonitrile particles, trade name "Tuftic AM", Toyobo Co., Ltd., volume average particle diameter: 10 μm, irregular shape

[0061] <Example 5> A release film was produced in the same manner as in Example 1, except that the amount of the resin particles A was changed to 15 parts by mass.

[0062] <Comparative Example 1> A release film was produced in the same manner as in Example 1, except that the resin particles A were not added to the release layer-forming composition.

[0063] <Comparative Example 2> A release film was produced in the same manner as in Comparative Example 1, except that 25 parts by mass of the following resin particles C were added to the release layer-forming composition. Resin particles C: Polyacrylic particles, trade name "MX-1000", Soken Chemical & Engineering Co., Ltd., volume average particle diameter: 10 μm, spherical

[0064] <Comparative Example 3> A release film was produced in the same manner as in Comparative Example 2, except that the amount of the resin particles C was changed to 40 parts by mass.

[0065] <Comparative Example 4> A release film was produced in the same manner as in Comparative Example 2, except that the 25 parts by mass of the resin particles C were changed to the following resin particles D. Resin particles D: Polyacrylic particles, trade name "MX-500", Soken Chemical & Engineering Co., Ltd., volume average particle diameter: 5 μm, spherical

[0066] <Comparative Example 5> A release film was produced in the same manner as in Comparative Example 4, except that the amount of the resin particles D was changed to 40 parts by mass.

[0067] <Evaluation Test> Using the produced release film, the following evaluation tests were conducted.

[0068] <Release layer thickness> The release layer of the produced release film was removed using methyl ethyl ketone, and the thickness of the release layer was calculated from the mass difference of the release film before and after the removal. The results are shown in Table 1.

[0069] <Adhesive residue> The release film was pressed onto the surface of a mirror-finished SUS (stainless steel) plate under the conditions of 180 °C, 16 MPa, and 5 minutes. After pressing, it was left to stand and cooled to room temperature (25 °C), and then the release film was peeled off from the SUS plate. The surface of the SUS plate was visually observed, and if no adhesive residue was observed, it was judged as OK, and if adhesive residue was observed, it was judged as NG, and the state of the adhesive residue was evaluated. The results are shown in Table 1.

[0070] <Surface resistivity> Using an insulation resistance meter (digital ultra-high resistance / microammeter, manufactured by Advantest Corporation), the surface resistivity of the release layer side of the release film was measured. Specifically, after leaving the release film in an atmosphere of 23 ± 2 °C and humidity of 50 ± 10% RH for 1 hour, the surface resistance value (Ω) after applying a voltage of 500 V for 1 minute was measured, and the surface resistivity (Ω / square) was calculated using the following formula. The results are shown in Table 1.

[0071] Surface resistivity = π(D + d) / (D - d) × R π: Pi, D: Inner diameter of the ring-shaped electrode, d: Outer diameter of the ring-shaped electrode, R: Surface resistance value The value of π(D + d) / (D - d) used in the calculation of the surface resistivity was 18.84.

[0072]

Table 1

[0073] As shown in the results of Table 1, the release film of the example in which the release layer contains polyacrylonitrile particles has a lower surface resistivity and better antistatic performance than the release film of the comparative example in which the release layer does not contain polyacrylonitrile particles.

Claims

1. A release film having a base material layer, a conductive layer, and a release layer in this order, wherein the release layer contains polyacrylonitrile particles.

2. The release film according to Claim 1, wherein the ratio (A / B) of the average particle diameter A of the polyacrylonitrile particles to the thickness B of the release layer is greater than 0.

7.

3. The release film according to Claim 1 or Claim 2, wherein the content of the polyacrylonitrile particles is 10% by mass or more of the entire release layer.

4. The release film according to any one of Claims 1 to 3, wherein the release layer contains an adhesive.

5. The release film according to any one of Claims 1 to 4, for temporarily protecting at least a part of the surface of an object.

6. The release film according to any one of Claims 1 to 5, for use in exposed molding.

7. A method for manufacturing an electronic component device, comprising: a step of sealing the periphery of an electronic component in a state where the release film according to any one of Claims 1 to 6 is in contact with at least a part of the surface of the electronic component; and a step of peeling the release film from the electronic component.

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