Laminated film

Abstract

The present invention relates to a laminated film comprising a base material and a functional layer that is provided on one surface side of the base material, wherein the compressive creep strain of the laminated film at 200°C is 4.9-20 um, and the storage elastic modulus of the laminated film at 200°C is 33 MPa or greater.

Description

Laminated film

[0001] This invention relates to a laminated film.

[0002] Semiconductor packages have a resin encapsulation section to protect the semiconductor elements, and curable resins such as thermosetting epoxy resins are widely used to form the resin encapsulation section. As a method for encapsulating semiconductor elements, the so-called compression molding method or transfer molding method is known, in which a substrate on which semiconductor elements are mounted is placed in the cavity of a mold, and the cavity is filled with curable resin to form the resin encapsulation section. In these encapsulation methods, the so-called Film-Assisted Molding (FAM) method is usually employed, in which a release film is placed on the cavity surface of the mold to prevent the resin encapsulation section from sticking to the mold.

[0003] One type of semiconductor package known is one in which a portion of the semiconductor element is left exposed rather than sealed.

[0004] Patent Document 1 describes a release film for semiconductor device manufacturing, in which the main surface requiring release properties is modified.

[0005] International Publication No. 2016 / 125796

[0006] However, with the film described in Patent Document 1, the sealing resin may seep out onto the surface of the semiconductor element to be exposed (bleed-out), potentially contaminating the semiconductor element surface.

[0007] Furthermore, in the film described in Patent Document 1, when the film is sandwiched between the semiconductor element and the mold, the film is crushed and protrudes into the sealing space, resulting in a portion of the sealing space not being filled with curable resin, which could cause defects in the resin-sealed portion (dents).

[0008] The present invention aims to provide a laminated film that, when used as a release film in the encapsulation process of semiconductor packages, is less prone to resin bleed-out and less prone to dent formation in the resin encapsulation area.

[0009] The present invention relates to the following laminated films: [1] A laminated film comprising a substrate and a functional layer provided on one side of the substrate, wherein the compressive creep strain of the laminated film at 200°C is 4.9 to 20 μm, and the storage modulus of the laminated film at 200°C is 33 MPa or more. [2] The laminated film according to [1], wherein the thickness of the substrate is 12 μm or more. [3] The laminated film according to [1] or [2], wherein the substrate has a fluororesin layer. [4] The laminated film according to any one of [1] to [3], wherein the substrate has a fluororesin layer and a high-elasticity film layer, and the storage modulus of the high-elasticity film layer at 200°C is 200 MPa or more. [5] The laminated film according to [4], wherein the high-elasticity film layer contains at least one resin selected from polyamide resin, polyester resin, and polystyrene resin. [6] The laminated film according to any one of [1] to [5], wherein the substrate has a fluororesin layer with a thickness of 12 μm or more. [7] The laminated film according to any one of [1] to [6], wherein the functional layer has at least one of an antistatic layer and a release layer. [8] The laminated film according to any one of [1] to [7], wherein the arithmetic mean roughness Ra of the other surface of the substrate is 0.3 to 5.0 μm. [9] The laminated film according to any one of any one of [1] to [8], used as a release film.

[10] The laminated film according to any one of [1] to [9], used in the manufacture of a semiconductor package.

[0010] According to the present invention, a laminated film is provided that, when used as a release film in the encapsulation process of semiconductor packages, is less prone to resin bleed-out and less prone to dent formation in the resin-encapsulated portion.

[0011] Figure 1 is a cross-sectional view of the laminated film according to this embodiment. Figure 2 is a cross-sectional view of the laminated film according to this embodiment.

[0012] Embodiments of the present invention will be described in detail below. However, the present invention is not limited to the following embodiments. In the present invention, the numerical range indicated using "~" includes the numerical values ​​before and after "~" as the minimum and maximum values, respectively. In the present invention, compressive creep strain is measured using a thermomechanical analyzer (TMA) apparatus. In the present invention, the storage modulus is measured in accordance with ISO 6721-4:1994 (JIS K7244-4:1999).

[0013] <Laminated Film> A laminated film according to an embodiment of the present invention (hereinafter also referred to as "this laminated film") comprises a substrate and a functional layer provided on one side of the substrate, and is characterized in that the compressive creep strain of the laminated film at 200°C is 4.9 to 20 μm. In this specification, the side of the substrate on which the functional layer is provided is hereinafter also referred to as the "first side of the substrate," and the other side of the substrate is hereinafter also referred to as the "second side of the substrate."

[0014] This laminated film has a compressive creep strain of 4.9 to 20 μm at 200°C and a storage modulus of 33 MPa or higher at 200°C, resulting in a laminated film that is less prone to resin bleed-out and less prone to dent formation in the resin-sealed area.

[0015] An example of the structure of this laminated film will be explained using the drawings. Figures 1 and 2 are schematic cross-sectional views showing an example of this laminated film.

[0016] The laminated film 10 shown in Figure 1 is an example having a base material 1 and a functional layer 2 provided on the first surface 1A of the base material.

[0017] The laminated film 10 shown in Figure 2 comprises a base material 1 and a functional layer 2 provided on the first surface 1A of the base material, and the functional layer 2 is an example in which an antistatic layer 3 and a release layer 4 are provided.

[0018] Furthermore, this laminated film may have other layers between the substrate and the functional layer.

[0019] (Base material) In this laminated film, it is preferable that the base material contains resin. Including resin is preferable because it allows for the production of a film with excellent conformability when this laminated film is used as a release film.

[0020] As for the resin contained in the base material, a crystalline thermoplastic resin is preferred from the viewpoint of having excellent heat resistance, strength, storage modulus, tensile elongation, and other mechanical properties when used at the mold temperature during sealing (for example, 180°C).

[0021] Examples of crystalline thermoplastic resins include fluororesins, polymethylpentene, syndiotactic polystyrene resins, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, and unoriented nylon. Among these, fluororesins are preferred from the viewpoint of excellent heat resistance and mold release properties. That is, it is preferable that the substrate has a fluororesin layer. As the fluororesin, fluoroolefin polymers are preferred. Fluoroolefin polymers are polymers having units based on fluoroolefins. Fluoroolefin polymers may further have other units besides those based on fluoroolefins.

[0022] Examples of fluoroolefins include tetrafluoroethylene (hereinafter also referred to as "TFE"), vinyl fluoride, vinylidene fluoride, trifluoroethylene, hexafluoropropylene, and chlorotrifluoroethylene. Fluoroolefins may be used individually or in combination of two or more. Examples of fluoroolefin polymers include ethylene-tetrafluoroethylene copolymer (ETFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoro(alkyl vinyl ether) copolymer (PFA), and tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymer (THV). Fluoroolefin polymers may be used individually or in combination of two or more. Among fluoroolefin polymers, ETFE is particularly preferred due to its high elongation at high temperatures. ETFE is a copolymer having TFE units and ethylene units (hereinafter also referred to as "E units").

[0023] In addition to the TFE units and E units, ETFE may have units based on a third monomer. The third monomer may be used alone or in combination of two or more. Examples of the third monomer include a monomer having a fluorine atom and a monomer not having a fluorine atom.

[0024] Examples of the monomer having a fluorine atom include the following monomers (a1) to (a5). Monomer (a1): fluoroolefins having 2 or 3 carbon atoms. Monomer (a2): X(CF ２ ) ｎ CY=CH ２ (where X and Y are each independently a hydrogen atom or a fluorine atom, and n is an integer of 2 to 8). Fluoroalkyl ethylenes represented by. Monomer (a3): fluorovinyl ethers. Monomer (a4): functional group-containing fluorovinyl ethers. Monomer (a5): fluorine-containing monomers having an aliphatic ring structure.

[0025] Examples of the monomer (a1) include fluoroethylenes (trifluoroethylene, vinylidene fluoride, vinyl fluoride, chlorotrifluoroethylene, etc.), fluoropropylenes (hexafluoropropylene (hereinafter also referred to as "HFP"), 2-hydroperfluoropropylene, etc.).

[0026] As the monomer (a2), monomers with n being 2 to 6 are preferred, and monomers with n being 2 to 4 are particularly preferred. Also, monomers in which X is a fluorine atom and Y is a hydrogen atom, that is, (perfluoroalkyl)ethylene are particularly preferred. Specific examples of the monomer (a2) include the following compounds. CF ３ CF ２ CH=CH ２ ,, CF ３ CF ２ CF ２ CF ２ CH=CH ２ ((perfluorobutyl)ethylene. Hereinafter, also referred to as "PFBE"), CF ３ CF ２ CF ２ CF ２ CF=CH ２CF ２ HCF ２ CF ２ CF=CH ２ CF ２ HCF ２ CF ２ CF ２ CF=CH ２ etc.

[0027] Specific examples of monomers (a3) ​​include the following compounds. Note that among these, the diene monomers are capable of cyclopolymerization. CF ２ = CFOCF ３ CF ２ = CFOCF ２ CF ３ CF ２ = CFO (CF ２ ) ２ CF ３ (Perfluoro(propyl vinyl ether. Hereinafter also referred to as "PPVE"), CF ２ = CFOCF ２ CF (CF ３ )O(CF ２ ) ２ CF ３ CF ２ = CFO (CF ２ ) ３ O(CF) ２ ) ２ CF ３ CF ２ = CFO (CF ２ CF (CF ３ )O) ２ (CF ２ ) ２ CF ３ CF ２ = CFOCF ２ CF (CF ３ )O(CF ２ ) ２ CF ３ CF ２ = CFOCF ２ CF = CF ２ CF ２ = CFO (CF ２ ) ２ CF = CF ２ etc.

[0028] Specific examples of monomers (a4) include the following compounds: CF ２ = CFO (CF ２ ) ３ CO ２ CH ３ CF ２ = CFOCF ２ CF (CF ３ )O(CF ２ ) ３ CO ２ CH ３ CF ２ = CFOCF ２ CF (CF ３ )O(CF ２ ) ２ SO ２ F etc.

[0029] Specific examples of monomers (a5) include perfluoro(2,2-dimethyl-1,3-dioxol), 2,2,4-trifluoro-5-trifluoromethoxy-1,3-dioxol, and perfluoro(2-methylene-4-methyl-1,3-dioxolane).

[0030] Examples of monomers that do not contain a fluorine atom include the following monomers (b1) to (b4): Monomer (b1): Olefins, Monomer (b2): Vinyl esters, Monomer (b3): ​​Vinyl ethers, Monomer (b4): Unsaturated acid anhydrides. Specific examples of monomer (b1) include propylene and isobutene. Specific examples of monomer (b2) include vinyl acetate. Specific examples of monomer (b3) include ethyl vinyl ether, butyl vinyl ether, cyclohexyl vinyl ether, and hydroxybutyl vinyl ether.

[0031] Specific examples of monomers (b4) include maleic anhydride, itaconic anhydride, citraconic anhydride, and 5-norbornene-2,3-dicarboxylic acid anhydride.

[0032] As the third monomer, monomer (a2), HFP, PPVE, and vinyl acetate are preferred due to their ease of adjusting the degree of crystallinity and their excellent tensile strength and elongation at high temperatures (especially around 180°C). ３CF ２ CH=CH ２ PFBE is more preferred, and PFBE is even more preferred.

[0033] In ETFE, the molar ratio of TFE units to E units (TFE units / E units) is preferably 80 / 20 to 40 / 60, more preferably 70 / 30 to 45 / 55, and particularly preferably 65 / 35 to 50 / 50. When the TFE units / E units are within the above range, ETFE exhibits excellent heat resistance and mechanical strength. The proportion of units based on the third monomer in ETFE is preferably 0.01 to 20 mol%, more preferably 0.10 to 15 mol%, and particularly preferably 0.20 to 10 mol%, relative to the total amount of all units constituting ETFE (100 mol%). When the proportion of units based on the third monomer is within the above range, ETFE exhibits excellent heat resistance and mechanical strength.

[0034] When the units based on the third monomer include PFBE units, the proportion of PFBE units is preferably 0.5 to 4.0 mol%, more preferably 0.7 to 3.6 mol%, and particularly preferably 1.0 to 3.6 mol%, relative to the total amount of all units constituting ETFE (100 mol%). When the proportion of PFBE units is within the above range, the tensile elongation at high temperatures (especially around 180°C) is improved.

[0035] The melting point of ETFE is preferably 190°C or higher, more preferably 200°C or higher, even more preferably 210°C or higher, and particularly preferably 220°C or higher. The upper limit of the melting point of ETFE is not particularly limited, but for example, it is 270°C. When the melting point of ETFE is within this range, the release film tends to have excellent tensile strength and elongation at high temperatures (especially around 180°C). "Melting point" refers to the temperature corresponding to the maximum value of the melting peak measured by differential scanning calorimetry (DSC).

[0036] The melt flow rate (MFR) of ETFE is preferably 2 to 40 g / 10 min, more preferably 3 to 30 g / 10 min, and particularly preferably 5 to 20 g / 10 min. When the ETFE MFR falls within this range, the release film exhibits greater elongation at high temperatures, resulting in excellent conformability to the mold. The ETFE MFR is measured according to ASTM D3159 at a load of 49 N and 297°C.

[0037] The base material may further contain other components besides the resin. Examples of other components include lubricants, antioxidants, antistatic agents, plasticizers, and mold release agents. In terms of minimizing mold contamination, the content of other components in the base material is preferably 5% by mass or less, more preferably 1% by mass or less, even more preferably 0.5% by mass or less, and particularly preferably 0% by mass (not included).

[0038] The substrate may consist of a single layer or a laminate of multiple layers. If the substrate consists of a single layer, it is preferably a fluororesin layer. If the substrate is a laminate, it is preferably a fluororesin layer and other layers. The other layer is preferably a highly elastic film layer having a storage modulus of 200 MPa or more at 200°C. A highly elastic film layer with a storage modulus of 200 MPa or more at 200°C is preferable because it has resistance to deformation at high temperatures (it is less likely to deform at high temperatures).

[0039] Examples of resins that constitute the high-elasticity film layer include polyvinyl chloride (PVC), polyester resins (polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), etc.), polyolefin resins (polyethylene, polypropylene, etc.), polyamide resins (PA6, PA66, PA11, PA12, PAMDX6, etc.), polyphenylene sulfide (PPS), and bio-derived resins (resins mainly composed of polylactic acid, cellulose, chitin, chitosan, kenaf, etc.). The high-elasticity film layer may consist of one or more resins. Among these, at least one selected from the group consisting of polyamide resins, polyester resins, and polystyrene resins is preferred in terms of excellent mechanical strength and film moldability.

[0040] The highly elastic film layer may further contain additives as needed. Examples of additives include colorants, antioxidants, thermal degradation inhibitors, and stabilizers.

[0041] When the substrate is a laminate, it is preferable that the second surface of the substrate be a fluororesin layer, from the viewpoint of high thermal stability and suppressing film decomposition, migration of low molecular weight components to the surface, and consequently contamination of mold surfaces, etc., that come into contact with the film, depending on the heating conditions during use. Furthermore, when the substrate is a laminate, a combination of one high-elasticity film layer and one to two fluororesin layers is preferable. A two-layer structure of high-elasticity film layer / fluororesin layer, or a three-layer structure of fluororesin layer / high-elasticity film layer / fluororesin layer is preferable. When the substrate is a laminate, the configuration of the laminated film is preferably a functional layer / high-elasticity film layer / fluororesin layer, or a functional layer / fluororesin layer / high-elasticity film layer / fluororesin layer.

[0042] When the substrate is a laminate, it is preferable that each layer is laminated via an adhesive layer. Examples of adhesive layers include layers formed from adhesives. The adhesive may be an adhesive known for dry lamination, for example. Examples of adhesives include polyvinyl acetate adhesives, polyacrylic acid ester adhesives consisting of homopolymers or copolymers of acrylic acid esters (ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, etc.), or copolymers of acrylic acid esters with other monomers (methyl methacrylate, acrylonitrile, styrene, etc.), cyanoacrylate adhesives, ethylene copolymer adhesives consisting of copolymers of ethylene with other monomers (vinyl acetate, ethyl acrylate, acrylic acid, methacrylic acid, etc.), cellulose adhesives, polyester adhesives, and polyamide adhesives. Examples of adhesives include: polyimide adhesives, amino resin adhesives made of urea resin or melamine resin, phenolic resin adhesives, epoxy adhesives, polyurethane adhesives made of combinations of polyols (polyether polyols, polyester polyols, etc.) and polyisocyanates or their reaction products (isocyanate group-containing polyurethane prepolymers, etc.), reactive (meth)acrylic adhesives, rubber adhesives made of chloroprene rubber, nitrile rubber, styrene-butadiene rubber, etc., silicone adhesives, and inorganic adhesives made of alkali metal silicates, low-melting-point glass, etc. The dry coating amount of the adhesive is 0.1 to 5 g / m². ２It may be. The thickness of the adhesive layer (μm) is the dry coating amount (g / m ２ ) Therefore, it can be converted using the density of the adhesive material.

[0043] In this laminated film, the arithmetic mean roughness Ra of the second substrate surface is preferably 0.3 to 5.0 μm. The second substrate surface is the surface opposite to the surface on which the functional layer is provided (the first substrate surface), and is the surface that comes into contact with the functional layer when the laminated film is wound up. A Ra of 0.3 μm or more on the second substrate surface is preferable because it reduces the likelihood of blocking, a phenomenon where the laminated films adhere tightly to each other and become difficult to peel off, at the contact surface. Furthermore, an Ra of 5.0 μm or less is preferable because it allows for the creation of a laminated film with a film surface that does not change in texture and tends to have uniform irregularities. From the viewpoint of slipperiness on the mold surface when applied to mold molding, Ra is more preferably 0.5 μm or more, more preferably 1.0 μm or more, and similarly, preferably 2.5 μm or less, more preferably 1.9 μm or less, even more preferably 1.8 μm or less, and particularly preferably 1.7 μm or less. The arithmetic mean roughness Ra is measured in accordance with JIS B0601:2013 (ISO 4287:1997, Amd. 1:2009). A surface roughness measuring instrument is used for measurement, and the ambient temperature is set to 23-25°C. To set the Ra of the second surface of the substrate within the above range, for example, a method can be used to transfer the irregularities of the original mold to the surface, as described later.

[0044] In this laminated film, the thickness of the substrate is preferably 12 to 500 μm, more preferably 25 to 300 μm, even more preferably 30 to 150 μm, particularly preferably 35 to 100 μm, and most preferably 35 to 75 μm, whether it is a single layer or a laminate. If the thickness of the substrate is 12 μm or more, the laminated film of this disclosure has superior release properties. If the thickness of the substrate is 500 μm or less, handling of this laminated film when used as a release film (for example, handling in a roll-to-roll manner) is easy, and wrinkles are less likely to occur when the release film is stretched and positioned to cover the cavity of the mold.

[0045] When the substrate is a laminate having a fluororesin layer and other layers, the thickness of the substrate may be 15 to 800 μm, more preferably 23 to 350 μm, and more preferably 28 to 250 μm. From the viewpoint of excellent film-forming properties and flexibility, the thickness of the fluororesin layer is preferably 12 μm or more, more preferably 20 μm or more, and even more preferably 25 μm or more. Furthermore, the thickness of the fluororesin layer is preferably 500 μm or less, more preferably 250 μm or less, and even more preferably 200 μm or less. The thickness of the fluororesin layer is preferably 12 to 500 μm, more preferably 20 to 250 μm, and even more preferably 25 to 200 μm. When there are multiple fluororesin layers in the laminate, it is preferable that the total thickness of the fluororesin layers satisfies the above range. Furthermore, the thickness of the other layers is preferably 3 to 300 μm, more preferably 3 to 100 μm, and even more preferably 3 to 50 μm. The thickness of the substrate is determined by observing the cross-section of the laminated film using an optical microscope, measuring the thickness of the layer corresponding to the substrate at five points, and calculating the average value.

[0046] Furthermore, from the viewpoint of flexibility, the ratio of the total thickness of the fluororesin layer to the total thickness of the other layers is preferably 1:9 to 9:1, more preferably 3:7 to 9:1, and even more preferably 4:6 to 9:1. Moreover, from the viewpoint of flexibility, the ratio of the total thickness of the fluororesin layer to the total thickness of the substrate is preferably 0.35 to 0.95, more preferably 0.45 to 0.95, even more preferably 0.45 to 0.90, and particularly preferably 0.50 to 0.90.

[0047] In this laminated film, the substrate preferably has a storage modulus at 200°C (hereinafter also referred to as "storage modulus (200°C)") of 33 MPa or more, more preferably 50 MPa or more, and even more preferably 80 MPa or more. A storage modulus (200°C) of 33 MPa or more is preferable because it reduces the occurrence of dents. The storage modulus (200°C) is also preferably 250 MPa or less, and more preferably 200 MPa or less. A storage modulus (200°C) of 250 MPa or less is preferable because it reduces the occurrence of wrinkles in the laminated film. To make the storage modulus (200°C) of the substrate within the above range, for example, the substrate may be made into a laminate having a fluororesin layer and a high-elasticity film layer. In such a substrate, the fluororesin layer is relatively flexible and the high-elasticity film layer is relatively rigid, so it is easy to achieve a specific storage modulus (200°C) for the substrate as a whole.

[0048] In this laminated film, the high-elasticity film in the substrate preferably has a storage modulus (200°C) of 200 MPa or more, and more preferably 250 MPa or more. If the storage modulus (200°C) is above the lower limit, it is preferable because a laminated film with a storage modulus (200°C) of 33 MPa or more can be easily obtained, and dent formation can be reduced. The storage modulus (200°C) of the high-elasticity film is also preferably 500 MPa or less, and more preferably 450 MPa or less. If the storage modulus (200°C) is below the upper limit, it is preferable because wrinkle formation in the laminated film can be reduced. To set the storage modulus (200°C) of the high-elasticity film layer within the above range, for example, the high-elasticity film layer may be composed of the resin described above.

[0049] (Functional layer) The functional layer is preferably a layer that has the necessary functions when the laminated film is used as a release film. Examples of such functions include tackiness, release properties, antistatic properties, and shape-imparting properties, and it is preferable that the functional layer has at least one of these functions.

[0050] The functional layer may comprise multiple layers necessary to exhibit various functions such as tackiness, release properties, antistatic properties, and shape-forming properties, or it may comprise layers corresponding to each function. If the functional layer has a single-layer structure, for example, the functional layer may be a release layer, or it may be an adhesive release layer. If the functional layer is a laminate of two or more layers, the functional layer may comprise a release layer and an antistatic layer, or it may comprise an adhesive release layer and an antistatic layer.

[0051] From the viewpoint of using the laminated film as a release film, the functional layer preferably has a release layer. The material of the release layer is not limited as long as it is a layer that has release properties. Furthermore, it is preferable that the release layer is adhesive in order to improve adhesion to the mold. From the viewpoint of the release layer being adhesive, it is preferable that it contains at least one resin selected from acrylic resin, urethane resin, polyester resin, and epoxy resin.

[0052] In particular, the release layer is more preferably made of an acrylic resin, and from the viewpoint of release properties for encapsulating resins (e.g., epoxy compounds) used in semiconductor encapsulation and heat resistance to withstand use in transfer molding processes where the mold and encapsulating resin are at high temperatures, it is especially preferable that the release layer contains a reaction-cured product of a hydroxyl group-containing acrylic polymer and a bifunctional or more isocyanate compound (hereinafter also referred to as a "polyfunctional isocyanate compound"). In this case, the hydroxyl group-containing (meth)acrylic polymer reacts with the polyfunctional isocyanate compound to crosslink and become a reaction-cured product. The release layer may also be a reaction-cured product of a hydroxyl group-containing (meth)acrylic polymer, a polyfunctional isocyanate compound, and other components.

[0053] The release layer may further contain other components such as release agents, antistatic agents, lubricants, colorants, and coupling agents.

[0054] Examples of release agents include silicone compounds and fluorine compounds.

[0055] Examples of antistatic agents include ionic liquids, conductive polymers, metal ion-conducting salts, and conductive fillers. Examples of ionic liquids include pyridinium, imidazolium, and other onium and fluorine compounds. Conductive polymers are polymers in which electrons move and diffuse along the polymer skeleton. Examples of conductive polymers include polyaniline polymers, polyacetylene polymers, poly-p-phenylene polymers, polypyrrole polymers, polythiophene polymers, and polyvinylcarbazole polymers. Examples of conductive fillers include metal ion-conducting salts, metals, metal oxides, metal coatings, metal oxide coatings, conductive carbon, and conductive carbon nanotubes. Examples of metal ion-conducting salts include lithium salt compounds. Examples of metal oxides in metal oxide fillers and metal oxide-coated fillers include tin oxide, tin-doped indium oxide, antimond-doped tin oxide, phosphorus-doped tin oxide, zinc antimonate, and antimony oxide.

[0056] Examples of lubricants include microbeads made of thermoplastic resin, fumed silica, and polytetrafluoroethylene (PTFE) fine particles. Examples of colorants include various organic and inorganic colorants, more specifically, cobalt blue, red iron oxide, and cyanine blue. Examples of coupling agents include silane coupling agents and titanate coupling agents.

[0057] It is even more preferable that the functional layer has two layers: a release layer and an antistatic layer. Having an antistatic layer is preferable because it can suppress the generation of static electricity when peeling the release film from the resin encapsulation part. When the functional layer has a release layer and an antistatic layer, it is preferable that the laminated film has the layers in the order of substrate, antistatic layer, and release layer.

[0058] The antistatic layer is not limited in material as long as it has an antistatic function, but it is preferable that it contains an antistatic agent. An example of an antistatic agent is the antistatic agent contained in the release layer mentioned above. The amount of antistatic agent in the antistatic layer is set appropriately so that the surface resistance value is within the desired range.

[0059] The antistatic layer preferably also contains a resin binder in order to enhance the dispersibility of the antistatic agent. Examples of the resin binder include the resin binders contained in the above functional layer. The resin binder preferably has heat resistance capable of withstanding heat (for example, 180°C) in the sealing process, and a thermosetting resin is preferred. Examples of the thermosetting resin include acrylic resins, silicone resins, and urethane resins. Acrylic resins obtained by crosslinking a carboxyl group-containing acrylic polymer with a polyfunctional aziridine compound or a polyfunctional epoxy compound, and acrylic resins obtained by crosslinking a hydroxy group-containing acrylic polymer with a polyfunctional isocyanate compound are preferred. Examples of other resin binders include polyester resins, polyamide resins, vinyl acetate resins, ethylene-vinyl acetate copolymers, ethylene-vinyl alcohol copolymers, chlorotrifluoroethylene-vinyl alcohol copolymers, tetrafluoroethylene-vinyl alcohol copolymers, and the like.

[0060] From the viewpoints of excellent heat resistance and dispersibility of the antistatic agent, a polyester resin or an acrylic resin is preferred as the resin binder. The resin binder may be crosslinked. When the resin binder is crosslinked, it has better strength and heat resistance than when it is not crosslinked.

[0061] The antistatic layer may contain a mold release agent, a lubricant, a coloring agent, or a coupling agent, and may be included in the above mold release layer.

[0062] From the viewpoints that various functions of the functional layer can be fully exerted and the mold release property with respect to the mold, the thickness of the functional layer is preferably 0.01 to 10 μm, more preferably 0.05 to 5 μm. The thickness of the functional layer can be measured by performing cross-sectional observation using an optical microscope. Also, from the viewpoints that various functions of the functional layer can be fully exerted and the mold release property with respect to the mold, the dry coating amount of the functional layer is preferably 0.01 to 20 g / m ２ is preferred, 0.01 to 10 g / m ２ is more preferred, 0.05 to 10 g / m ２This is particularly preferable. The dry coating amount of the functional layer can be calculated by removing the layer to be measured using a solvent and taking the change in mass before and after removal. Details will be explained in the examples. Note that the thickness of the functional layer (μm) and the dry coating amount (g / m) are as follows. ２ These can be converted to each other using the density of the material in the functional layer.

[0063] When the functional layer is a multilayer having an antistatic layer and a release layer, the thickness of the antistatic layer is 0.01 to 10 g / m² as the dry coating amount of the antistatic layer composition. ２ It may be as follows. The thickness of the release layer may be 0.01 to 50 g / m² as the dry coating amount of the release layer composition. ２ That's fine.

[0064] The surface of the functional layer (the surface opposite to the substrate side) may have a minute uneven surface. The surface of the functional layer is the surface that comes into contact with the curable resin when the laminated film is used as a release film. Therefore, it is preferable that this surface has a minute uneven surface, as this makes it possible to form a semiconductor package surface with excellent laser marking visibility. Specifically, the Ra of the functional layer surface is preferably 0.1 μm or more, and more preferably 0.3 μm or more.

[0065] (Physical Properties of Laminated Film) This laminated film has a compressive creep strain at 200°C (hereinafter also referred to as "compressive creep strain (200°C)") of 4.9 to 20 μm. Compressive creep strain is an indicator of how a film deforms when a constant force is applied in the thickness direction. Furthermore, since semiconductor encapsulation processes are generally carried out in a high-temperature range of around 170°C, the behavior of the film's compressive creep strain is considered to become more apparent under 200°C conditions. A compressive creep strain (200°C) of 4.9 μm or more improves the overall cushioning properties of the laminated film, suppressing the occurrence of wrinkles during mold formation, thus reducing the likelihood of resin bleed-out. Additionally, a compressive creep strain (200°C) of 20 μm or less provides adequate cushioning to prevent the film from collapsing during mold formation, thus reducing the likelihood of dents occurring in the resin-encapsulated area. The compressive creep strain (at 200°C) is preferably 4.9 to 19 μm, more preferably 5.0 to 19 μm, and even more preferably 5.1 to 18 μm. To achieve the above range for the compressive creep strain (at 200°C) of the laminated film, for example, the substrate may be made into a laminate having a fluororesin layer and a high-elasticity film layer. In such a laminate, the fluororesin layer is relatively flexible and the high-elasticity film layer is relatively rigid, making it easier to achieve a specific compressive creep strain (at 200°C) for the laminate as a whole.

[0066] This laminated film has a storage modulus at 200°C (hereinafter also referred to as "storage modulus (200°C)") of 33 MPa or more. If the storage modulus (200°C) is 33 MPa or more, dent generation can be reduced, which is preferable. The storage modulus (200°C) is preferably 50 MPa or more, more preferably 80 MPa or more. The storage modulus (200°C) is also preferably 250 MPa or less, more preferably 200 MPa or less. If the storage modulus (200°C) is 250 MPa or less, wrinkle generation in the laminated film can be reduced, which is preferable. To set the storage modulus (200°C) of this laminated film within the above range, for example, making the base material a laminate having a fluororesin layer and a high-elasticity film layer, etc. can be mentioned. In such a laminate, since the fluororesin layer is relatively flexible and the high-elasticity film layer is relatively rigid, it is easy to achieve a specific storage modulus (200°C) for the entire laminate.

[0067] It is preferable that the Ra of the surface on the functional layer side of this laminated film is 0.01 μm or more, more preferably 0.03 μm or more. When it is desired to form a semiconductor package surface excellent in laser marking visibility, it is preferable that the Ra of the surface on the functional layer side is 0.1 μm or more, more preferably 0.3 μm or more. It is preferable that the Ra of the surface on the base material side of this laminated film is 0.3 to 5.0 μm, more preferably 0.3 to 1.9 μm. For Ra, 0.5 μm or more is more preferable, and 1.9 μm or less is more preferable. Ra may be 0.5 to 1.9 μm, or may be 0.5 to 1.8 μm.

[0068] The surface resistivity of the surface on the functional layer side of this laminated film is １０ preferably 1×10 ９ Ω / □ or less, more preferably 5×10 ９ Ω / □ or less, even more preferably 3×10 １０ Ω / □ or less. If the surface resistivity is 1×10 ７The surface resistivity may be greater than or equal to Ω / □. To achieve the above surface resistivity, for example, the content of the antistatic agent in the functional layer can be adjusted. The surface resistivity can be measured in accordance with IEC 60093, the double-ring electrode method.

[0069] The tensile elongation of this laminated film at 175°C is preferably 100 to 1000%, more preferably 200 to 800%, and even more preferably 350 to 500%. This range of tensile elongation is preferable because it allows the laminated film to conform well to the shape of the mold when used as a release film. Furthermore, a tensile elongation above the lower limit is preferable because it reduces the likelihood of film tearing during mold conformation.

[0070] <Method for Manufacturing Laminated Film> From the standpoint of productivity, the base material can be manufactured by, for example, the following methods (i) or (ii): (i) A method of passing a resin film between two rolls and forming it to a desired thickness. (ii) A method of passing resin extruded from the die of an extruder between two rolls and forming the resin into a film of a desired thickness.

[0071] To give the second surface of the substrate an uneven shape with a specific range of Ra, one method is to transfer the original mold's unevenness to the second surface of the resin film substrate by heat processing. For example, the following methods (i') or (ii') can be used. (i') A method in which a resin film is passed between two rolls, and the unevenness formed on the surface of the rolls is continuously transferred to the surface (second surface) where the unevenness of the resin film is formed. (ii') A method in which resin extruded from the die of an extruder is passed between two rolls, the resin is formed into a film, and the unevenness formed on the surface of the rolls is continuously transferred to the surface (second surface) where the unevenness of the film-like resin is formed. The roll surface in contact with the first surface of the substrate may be a mirror surface or an uneven shape.

[0072] Furthermore, in order to change Ra within a specific range, methods include changing the uneven shape of the original mold according to the desired Ra, changing the thickness of the resin film or resin passed through the two rolls, changing the temperature of the resin film, changing the film formation speed when the film is formed by continuously extruding and the surface shape is formed by passing it through the two rolls, and changing the force applied from the rolls to the resin film or resin.

[0073] Furthermore, if the substrate is a laminate comprising a layer containing fluororesin and other layers, for example, a resin film can be produced by laminating the layer containing fluororesin and other layers using dry lamination with an adhesive, and the substrate can be obtained by method (i) or method (i') described above.

[0074] The functional layer is formed, for example, by a coating method in which a functional layer composition described later is applied to the first surface of a substrate. When the functional layer is a single layer, a method of applying the functional layer composition to the first surface of the substrate and drying is preferred. Various known wet coating methods can be used for the coating method, such as gravure coating, die coating, and bar coating. The drying temperature and time are adjusted as appropriate depending on the type and content of the liquid medium.

[0075] When the functional layer is a multilayer including an antistatic layer and a release layer, it is preferable to apply an antistatic layer composition containing an antistatic agent, etc., to the first surface of the substrate, dry it to form the antistatic layer, and then apply a release layer composition on top of the antistatic layer and dry it to form the release layer. Various known wet coating methods can be used for the coating method, such as the gravure coating method, die coating method, and bar coating method. The drying temperature and time are adjusted as appropriate depending on the type and content of the liquid medium. The antistatic layer composition and the release layer composition may each contain the components that make up each layer, and optionally a curing agent, a solvent, water, or other liquid medium.

[0076] Before applying the functional layer composition or the antistatic layer composition, it is preferable to corona treat the first surface of the substrate to improve wettability. The corona treatment is preferably carried out so that the wettability tension, according to ISO 8296:1987 (JIS K6768:1999), is 40 mN / m or more.

[0077] The drying temperature and time for the functional layer should be adjusted as appropriate depending on the type and content of the liquid medium.

[0078] <Method for Manufacturing Semiconductor Packages> This laminated film is useful as a release film used in the sealing process when manufacturing a semiconductor package having a semiconductor element and a resin sealing portion formed from a curable resin that seals the semiconductor element. A method for manufacturing a semiconductor package using this laminated film includes, for example, placing a substrate equipped with a semiconductor element in the cavity of a mold, placing a release film made of this laminated film on the cavity surface of the mold where the substrate is not placed, with the functional layer side of the laminated film facing the space inside the cavity of the mold, filling the cavity with a curable resin, and curing the curable resin in contact with the release film to form a resin sealing portion that seals the semiconductor element. Examples of curable resins include epoxy resins. The curable resin may also be used as a composition containing a curing agent. The curing agent may be an amine-based curing agent.

[0079] The semiconductor package manufacturing method of this disclosure can employ known manufacturing methods, except for the use of the laminated film as a release film. For example, compression molding or transfer molding can be used as methods for forming the resin encapsulation portion, and known compression molding apparatus or transfer molding apparatus can be used as the equipment in this process. The manufacturing conditions are also the same as those in known semiconductor package manufacturing methods.

[0080] The present invention will be described in more detail below using examples, but the present invention is not limited to these. Examples 1 to 11, 13, and 17 to 20 are examples. Example 16 is a comparative example. Examples 12, 14, and 15 are reference examples.

[0081] <Materials Used> (Base Material) ETFE (1): Fluon® ETFE C-88AXP (AGC Corporation) ETFE (2): Fluon® ETFE LM-720AX (AGC Corporation) PET (1): Toyobo Co., Ltd., Toyobo Ester® Film G200X, 25 μm thick, storage modulus (200°C) 300 MPa PET (2): Toyobo Co., Ltd., Toyobo Ester® Film NS000, 12 μm thick, storage modulus (200°C) 400 MPa PET (3): Toyobo Co., Ltd., Toyobo Ester® Film G200X, 38 μm thick, storage modulus (200°C) 250 MPa PET (4): Toray Industries, Inc., Lumirror® Film 6C, 6 μm thickness, storage modulus (200°C) 440 MPa. Urethane adhesive: The main component and hardener were mixed so that the mass ratio (main component:hardener) in terms of solid content was 10:1, and the urethane adhesive was prepared by diluting with ethyl acetate. Main component: Crisbon (registered trademark) NT-258 (manufactured by DIC Corporation). Hardener: Coronate 2096 (manufactured by Nippon Polyurethane Industry Co., Ltd.).

[0082] (Composition for antistatic layer) An antistatic layer composition (solids content 2% by mass) was prepared by mixing an antistatic agent-containing material (100 parts by mass), a curing agent (10 parts by mass), and methanol (100 parts by mass). Antistatic agent-containing material: Aracoat® AS601D (manufactured by Arakawa Chemical Industries, Ltd.), solids content 3.4%, conductive polythiophene 0.4%, acrylic resin 3.0%. Curing agent: Aracoat® CL910 (manufactured by Arakawa Chemical Industries, Ltd.), solids content 10%, polyfunctional aziridine compound.

[0083] (Composition for mold release layer) A mold release layer composition (solid content 25% by mass) was prepared by mixing an acrylic polymer (100 parts by mass), a polyfunctional isocyanate compound (4 parts by mass), and ethyl acetate. Acrylic polymer: Nissetsu (registered trademark) KP2562 (manufactured by Nippon Carbide Industries Co., Ltd.). Polyfunctional isocyanate compound: Nissetsu CK157 (manufactured by Nippon Carbide Industries Co., Ltd.), solid content 100%, isocyanurate-type hexamentiene diisocyanate, NCO content 21% by mass.

[0084] <Example 1> ETFE (1) was fed into an extruder equipped with a T-die, and taken up between a rubber-wrapped roll having an uneven surface and a metal roll having a mirror surface to produce an ETFE film with the thickness and surface roughness shown in Table 1. The temperature of the extruder and T-die was 320°C, and the temperature of the rubber-wrapped roll and metal roll was 100°C. A urethane-based adhesive was applied to one side of PET using a gravure roll and dried at 60°C. An ETFE film was placed on this coated surface and roll-pressed at 60°C and 1 m / min to obtain a PET / ETFE laminate. A urethane-based adhesive was applied to the PET side of this laminate and dried at 60°C. ETFE was placed on this coated surface and roll-pressed at 60°C and 1 m / min to obtain an ETFE / PET / ETFE laminate. An ETFE / PET / ETFE laminate was fed into an extruder equipped with a T-die, and taken up between a rubber-wrapped roll having an uneven surface and a metal roll having a mirror surface to produce a substrate with an uneven surface (second substrate surface) and a mirror surface (first substrate surface), as shown in Table 1. The temperature of the extruder and T-die was 320°C, and the temperature of the rubber-wrapped roll and metal roll was 100°C. The surface of the first substrate surface was subjected to corona treatment so that the wetting tension according to ISO 8296:1987 (JIS K6768:1999) was 40 mN / m or more. An antistatic layer composition was coated onto the surface of the first substrate surface (the surface on the substrate layer 3 side) using a gravure coater and dried to form an antistatic layer. Coating was performed using the reverse gravure method, and drying was carried out at 100°C for 1 minute. Next, a release layer composition was applied to the surface of the antistatic layer using a gravure coater and dried to form a release layer. The coating was performed using a reverse gravure method, and drying was carried out at 100°C for 1 minute. Then, the film was cured at 40°C for 120 hours to obtain a laminated film. The first surface of the substrate is the surface of the substrate on which the functional layer is provided. The second surface of the substrate is the surface of the substrate opposite to the surface on which the functional layer is provided.

[0085] <Examples 2-20> ETFE (1) and (2) were fed into an extruder equipped with a T-die, and taken up between a rubber-wound roll having an uneven surface and a metal roll having a mirror surface to produce ETFE films with the thickness and surface roughness shown in Tables 1-3. The temperature of the extruder and T-die was 320°C, and the temperature of the rubber-wound roll and metal roll was 100°C. Laminated films were obtained in the same manner as in Example 1, except that the composition of the substrate was changed as shown in Tables 1-3.

[0086] [Evaluation Method] (Thickness of base material and laminated film) The thickness (μm) of the base material and laminated film was determined by measuring the cross-section at five points using an optical microscope and calculating the average value.

[0087] (Coating amount of antistatic layer and release layer) A 12 cm x 12 cm piece was cut from the laminated film, and the layer to be measured was removed by rubbing it with a 500 g load using a Kimwipe impregnated with a solvent. The coating amount (solid content) was calculated from the change in mass before and after removal. The layer removal was performed by using both isopropyl alcohol and ethyl acetate as solvents separately and sequentially. Layer removal and mass measurement were continued until the measured mass no longer changed. The load was measured by placing a glass plate on a balance and rubbing on it.

[0088] (Arithmetic mean roughness (surface roughness) Ra) Ra (μm) was measured according to JIS B0601:2013 (ISO 4287:1997, Amd. 1:2009). The reference length lr (cutoff value λc) was 0.8 mm, and the measurement length was 8 mm. For the measurement, a surface roughness measuring instrument (SURFCOM 480A, manufactured by Tokyo Seimitsu Co., Ltd.) was used, and Ra was determined at a total of 6 locations: 3 locations perpendicular to the flow direction during film manufacturing and 3 locations parallel to it. The average value of these values ​​was taken as the Ra of the surface in question.

[0089] (Compressive creep strain (200°C)) Compressive creep strain was measured in compression mode using a thermomechanical analyzer (TMA) (model number SS-6100) manufactured by SII Corporation, according to the following conditions. Each laminated film was measured with a length of 0.075 mm and a cross-sectional area of ​​25 mm². ２The sample was processed to obtain a sample for measurement. Under a constant load of 20 mN, the temperature was raised to 200°C at a heating rate of 50°C / min and held for 30 minutes. Subsequently, a load was applied from 20 mN (compressive stress 0.102 MPa) to 1400 mN (compressive stress 7.13 MPa) at a constant pressing rate (9.8E+06 mN / min). The compressive creep strain (μm) was then measured when the sample was held under a constant load of 1400 mN for 3 minutes.

[0090] (Storage Modulus (200°C)) The storage modulus was measured in tensile mode according to ISO 6721-4:1994 (JIS K7244-4:1999) using a dynamic viscoelasticity (DMA) measuring device (model number DMA7100) manufactured by Hitachi High-Tech Corporation, under the following conditions. Each laminated film was processed to dimensions of 20 mm in length and 8 mm in width to obtain measurement samples. Samples were prepared for both the MD direction and the TD direction. Under a measurement frequency of 10 Hz, the temperature was raised from 30°C to 220°C at a heating rate of 2°C / min, and the storage modulus at 200°C was measured.

[0091] (Resin Bleed and Dents) The laminated film of each example was used as a release film (slit roll, 190 mm wide), and resin-encapsulated products were manufactured using the following procedure. An auto-molding device MSL-06M manufactured by Apic Yamada was used to prepare a semiconductor encapsulation mold designed to transfer mold a chip substrate with a width of 70 mm and a length of 230 mm, on which 2 mm × 2 mm × 200 μm Si chips were laminated, with a cavity depth of 0.20 mm. The release film was heated to 175°C and attached to the upper mold using a film adsorption mechanism with an air intake function that applied an adsorption differential pressure of 90 to 100 kPa. Next, the chip substrate was placed in the lower mold, the upper and lower molds were clamped together with 490 kN, and epoxy resin tablets were loaded into the material supply section specified by the device and injected at a pressure of 4.9 MPa. After holding for 150 seconds, the mold was opened and the resin-encapsulated product was removed. The resin-encapsulated product was visually inspected and evaluated according to the following criteria. Resin bleed: A: No bleed of the sealing resin on the exposed surface (Pass) B: The sealing resin has bled onto the exposed surface (Fail) Dents: A: No dents have formed in the sealing resin (Pass) B: Dents have formed in the sealing resin (Fail)

[0092] (Presence or absence of electrostatic discharge breakdown) A transfer mold test was conducted using an Apic Yamada Co., Ltd. molding device and an Apic Yamada Co., Ltd. transfer mold. Sumitomo Bakelite EGE 770GH was used as the sealing material. The molding temperature was 175°C. Molding was performed using a 73 mm wide, 230 mm long, and 200 μm thick Tip copper substrate. The mold depth was set to 0.4 mm so that a 200 μm thick EMC-cured material could be molded onto the copper plate. During molding, the device was stopped 30 seconds after the mold opened, and the electrostatic charge potential was measured using a charge meter (Keyence Corporation, electrostatic charge meter SK-H050) and evaluated according to the following criteria. A: Electrostatic charge potential less than 10 kV (no electrostatic discharge breakdown occurred, pass) B: Electrostatic charge potential 10 kV or more (electrostatic discharge breakdown occurred, fail)

[0093] (Presence or absence of surface morphological abnormalities in molded products) A transfer mold test was conducted using an Apic Yamada Co., Ltd. transfer mold installed in an Apic Yamada Co., Ltd. molding device. Sumitomo Bakelite EGE 770GH was used as the sealing material. The molding temperature was 175°C. Molding was performed using a 73 mm wide, 230 mm long, and 200 μm thick Tip copper substrate. The depth of the mold was set to 0.4 mm so that a 200 μm thick EMC cured product could be molded onto the copper plate. Visual inspection of the sealing resin surface of the obtained molded product revealed that the surface texture of the film used had been transferred. The product was evaluated according to the following criteria: A: The appearance is uniform (no morphological abnormalities, pass) B: Irregularities on the surface of the laminated film are unevenly transferred (morphological abnormalities present, fail)

[0094] The results are shown in Tables 1-3.

[0095]

[0096]

[0097]

[0098] Laminated films in Examples 1-11, 13, and 17-20, which had a compressive creep strain in the range of 4.9 to 20 μm at 200°C and a storage modulus of 33 MPa or higher at 200°C, showed good results in resin bleed and dent evaluation. Of these, laminated films in Examples 1-11, 13, and 17-19, in which the Ra of the second surface of the substrate was in the range of 0.3 to 5.0 μm, did not exhibit surface morphological abnormalities in molded products. However, laminated film in Example 20, in which the Ra of the second surface of the substrate was less than 0.3 μm, developed mold surface abnormalities due to blocking induction.

[0099] Laminated films in Examples 12, 14, and 15, which had a compressive creep strain less than 4.9 μm at 200°C, showed insufficient resin bleed evaluation results. Laminated film in Example 16, which had a storage modulus of less than 33 MPa at 200°C, showed insufficient dent evaluation results. Furthermore, laminated films in Examples 14 and 15, where the Ra of the second substrate surface was less than 0.3 μm, exhibited surface morphological abnormalities in molded products.

[0100] Furthermore, in the laminated films of Examples 1 to 20, no electrostatic discharge (ESD) breakdown occurred because the functional layer had an antistatic layer.

[0101] Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. This application is based on Japanese Patent Application No. 2024-173375 filed on 2 October 2024, the contents of which are incorporated herein by reference.

[0102] The laminated film disclosed in this invention is useful as a release film that is less prone to resin bleed-out and less prone to dent formation in the resin-sealed portion during the encapsulation process of semiconductor packages. Semiconductor packages can be manufactured using the laminated film disclosed herein.

[0103] 10 Laminated Film 1 Substrate 1A Substrate 1st surface (one side of the substrate) 1B Substrate 2nd surface (the other side of the substrate) 2 Functional layer 3 Antistatic layer 4 Release layer

Claims

1. A laminated film comprising a base material and a functional layer provided on one side of the base material, wherein the laminated film has a compressive creep strain of 4.9 to 20 μm at 200°C and a storage modulus of 33 MPa or more at 200°C.

2. The laminated film according to claim 1, wherein the thickness of the substrate is 12 μm or more.

3. The laminated film according to claim 1, wherein the substrate has a fluororesin layer.

4. The laminated film according to claim 1, wherein the substrate comprises a fluororesin layer and a high-elasticity film layer, and the storage modulus of the high-elasticity film layer at 200°C is 200 MPa or more.

5. The laminated film according to claim 4, wherein the highly elastic film layer comprises at least one resin selected from polyamide resin, polyester resin, and polystyrene resin.

6. The laminated film according to claim 1, wherein the substrate has a fluororesin layer with a thickness of 12 μm or more.

7. The laminated film according to claim 1, wherein the functional layer has at least one of an antistatic layer and a release layer.

8. The laminated film according to claim 1, wherein the arithmetic mean roughness Ra of the other surface of the substrate is 0.3 to 5.0 μm.

9. A laminated film according to any one of claims 1 to 8, used as a release film.

10. A laminated film according to any one of claims 1 to 8, used in the manufacture of a semiconductor package.

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