Thermoplastic release film for semiconductor packaging processes, and methods for manufacturing electronic components using the same.

Abstract

This invention provides a thermoplastic release film for semiconductor packaging processes and a method for manufacturing electronic components using the same. The thermoplastic release film for semiconductor packaging processes has a low cost, is halogen-free, has excellent thickness accuracy and release properties, and exhibits good film handling and mold following properties during high-temperature compression molding with minimal wrinkling, thus reducing the occurrence of appearance defects in the resin molded part. The thermoplastic release film for semiconductor packaging processes contains at least a thermoplastic crystalline cyclic polyolefin and a polyolefin-based thermoplastic elastomer. In dynamic viscoelastic spectroscopy measurements, the minimum value of the storage modulus E'1 in the range of 80–150°C and the storage modulus E'2 at 175°C satisfy the following equations (1) and (2): 10MPa≤E'1≤100MPa (1) E'1≥E'2 (2).

Description

Technical Field

[0001] This invention relates to thermoplastic release films for semiconductor packaging processes, and methods for manufacturing electronic components using the same. Background Technology

[0002] In the past, during the resin molding process of semiconductor components on various packaging substrates such as multilayer printed wiring boards and flexible printed wiring boards, release films were generally used to obtain the release properties of the cured packaging resin from the mold (see Patent Documents 1 and 2).

[0003] As such release films, fluoropolymer films such as ethylene-tetrafluoroethylene copolymer (ETFE) and polytetrafluoroethylene (PTFE) are widely used due to their superior heat resistance, release properties, and mold followability. For example, Patent Document 3 discloses a release film for resin molding, characterized in that it is a release film for resin molding formed from a thermoplastic tetrafluoroethylene copolymer, wherein the elongation and shrinkage rates of the film in both the length and width directions are within the range of 0 to -10%.

[0004] However, release films using fluoropolymer membranes contain a large number of fluorine atoms, which are halogen atoms. The thermal decomposition products of the fluoropolymer membrane adhere to the inner surface of the mold, contaminating it and easily causing poor appearance in the resin molding section. Not only is there room for improvement in release properties, but the cost is also relatively high. Furthermore, there are concerns about the generation of harmful substances such as hydrogen fluoride and perfluoroisobutylene during the incineration of waste fluoropolymer membranes, thus requiring special recycling treatment and exhibiting poor versatility.

[0005] Therefore, the use of special non-fluorinated resins such as polystyrene (PS) and polymethylpentene (PMP) is being studied as such release films. However, these resins have poor heat resistance, poor film transportability in high-temperature encapsulation processes, and are prone to wrinkles when installed on the inner surface of the mold. These wrinkles are transferred to the surface of the molded product and easily cause poor appearance, resulting in problems such as poor mold followability.

[0006] On the other hand, the use of cross-linked cyclic polyolefins as non-fluorinated resins has also been studied. For example, Patent Document 4 discloses a cross-linked resin film obtained by polymerizing a liquid containing a metasomatic polymerization catalyst and a metasomatically polymerizable cyclic olefin on a carrier, and studies its use as a release film. Furthermore, Patent Document 5 discloses a release film formed from a resin composition comprising a cross-linked cyclic olefin polymer and an elastomer incompatible with the polymer, and studies its use as a release film in semiconductor packaging processes.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2000-167841

[0010] Patent Document 2: Japanese Patent Application Publication No. 2001-250838

[0011] Patent Document 3: Japanese Patent Application Publication No. 2001-310336

[0012] Patent Document 4: Japanese Patent Application Publication No. 2001-253934

[0013] Patent Document 5: Japanese Patent Application Publication No. 2011-178953 Summary of the Invention

[0014] The problem that the invention aims to solve

[0015] However, the cross-linked resin film described in Patent Document 4 lacks flexibility (mold followability) and also has poor release properties, thus making it unsuitable as a release film for mold protection used in the resin molding process.

[0016] On the other hand, while the release film described in Patent Document 5 improves softness and release properties, it is obtained by bulk polymerization of a resin composition containing a cross-linked cyclic olefin polymer, an elastomer incompatible with the polymer, and a polymerizable composition containing a polymerization catalyst. This results in difficulties in uniformly stirring high-viscosity liquids, residues of unreacted monomers, and precise control of the reaction temperature to suppress thermal runaway, leading to poor productivity. Furthermore, the release film described in Patent Document 5 has relatively low tensile strength, which makes it prone to wrinkling and other appearance defects when used as a release film for mold protection at relatively high temperatures (e.g., 175°C).

[0017] The present invention was made in view of the above-mentioned problems. That is, the object of the present invention is to provide a thermoplastic release film for semiconductor packaging processes and a method for manufacturing electronic components using the same, etc. The thermoplastic release film for semiconductor packaging processes has low cost, can be made halogen-free, has excellent thickness accuracy and release properties, and has good film handling and mold following properties during high-temperature compression molding with less wrinkling, thereby reducing the occurrence of appearance defects in resin molded parts.

[0018] Methods for solving problems

[0019] In order to solve the above-mentioned problems, the inventors of this application conducted in-depth research on various release films and discovered a new type of thermoplastic resin film containing at least thermoplastic crystalline cyclic polyolefin and polyolefin-based thermoplastic elastomer, and having a specified storage modulus in dynamic viscoelastic spectrum measurement. Furthermore, they found that by using it as a release film for semiconductor packaging processes, the above-mentioned problems can be solved, thus completing the present invention.

[0020] That is, the present invention provides various specific methods as shown below.

[0021] (1) A thermoplastic release film for semiconductor packaging processes, comprising at least a thermoplastic crystalline cyclic polyolefin and a polyolefin-based thermoplastic elastomer.

[0022] In dynamic viscoelastic spectroscopy measurements, the minimum value of the storage modulus E'1 in the range of 80–150 °C and the storage modulus E'2 at 175 °C satisfy the following equations (1) and (2):

[0023] 10MPa≤E'1≤100MPa (1)

[0024] E'1≥E'2 (2).

[0025] (2) The thermoplastic release film for semiconductor packaging process described in (1), wherein, in the above dynamic viscoelastic spectrum determination, the above E'2 satisfies the following equation (3):

[0026] 10MPa≤E'2≤100MPa (3).

[0027] (3) The thermoplastic release film for semiconductor packaging process as described in (1) or (2), wherein it contains 15 to 75% by mass of the above-mentioned thermoplastic crystalline cyclic polyolefin and 5 to 75% by mass of the above-mentioned polyolefin-based thermoplastic elastomer.

[0028] (4) The thermoplastic release film for semiconductor packaging process described in (3) further contains 3 to 45% by mass of high melt tension polypropylene.

[0029] (5) The thermoplastic release film for semiconductor packaging process described in (4), wherein the high melt tension polypropylene comprises a propylene polymer with a long chain branching structure having a melt tension (230°C) of 3 to 30 g and a melt flow rate (based on JIS K7210:1999, 230°C, 2.16 kg load) of 0.9 g to 15 g / 10 min or less.

[0030] (6) The thermoplastic release film for semiconductor packaging process described in any of (1) to (5) has a cold crystallization heat of less than 5.0 J / g in differential scanning calorimetry.

[0031] (7) The thermoplastic release film for semiconductor packaging process described in any one of (1) to (6) has a film thickness of 10 μm or more and 300 μm or less.

[0032] (8) The thermoplastic release film for semiconductor packaging process described in any one of (1) to (7), wherein the polyolefin thermoplastic elastomer comprises one or more selected from the group consisting of ethylene-α-olefin copolymer, propylene-α-olefin copolymer and ethylene-propylene-diene copolymer.

[0033] (9) A thermoplastic release film for semiconductor packaging process as described in any one of (1) to (8), wherein the thermoplastic crystalline cyclic polyolefin has a melting point of 250°C or higher.

[0034] (10) A method for manufacturing electronic components, comprising at least the following steps:

[0035] Preparation process: The thermoplastic release film of the semiconductor packaging process described in any one of (1) to (9) is placed on the inner surface of the mold of the packaging device, wherein the packaging device is a packaging device for resin encapsulating part or all of the semiconductor elements arranged on the substrate in the mold.

[0036] The process of adding resin into the mold in which the above-mentioned thermoplastic release film for semiconductor packaging process is disposed;

[0037] The packaging process involves closing the mold to seal the semiconductor element with the resin, thereby resin encapsulating part or all of the semiconductor element; and

[0038] The demolding process involves peeling the thermoplastic release film used in the semiconductor packaging process from the mold.

[0039] (11) The method for manufacturing an electronic component as described in (10), wherein the substrate is a multilayer printed wiring board and / or a flexible printed wiring board.

[0040] Invention Effects

[0041] According to one embodiment of the present invention, a thermoplastic release film for semiconductor packaging processes and a method for manufacturing electronic components using the same can be realized. The thermoplastic release film for semiconductor packaging processes has a low cost, is halogen-free, has excellent thickness accuracy and release properties, and exhibits good film transportability and mold following properties during high-temperature compression molding with minimal wrinkling, thereby reducing the occurrence of appearance defects in the resin molded portion. Attached Figure Description

[0042] [ Figure 1 This is a schematic diagram illustrating an example of the use of a thermoplastic release film 100 according to one embodiment.

[0043] [ Figure 2 [Figure 1] is a graph showing the results of the dynamic viscoelastic spectra of the release films of Example 4 and Comparative Example 1. Detailed Implementation

[0044] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Unless otherwise specified, positional relationships such as up, down, left, and right are based on the positional relationships shown in the accompanying drawings. Furthermore, the scale of the accompanying drawings is not limited to the scale shown. It should be noted that the following embodiments are illustrative of the present invention, and the present invention is not limited thereto. That is, the present invention can be implemented in any way without departing from its spirit. It should be noted that in this specification, for example, the expression of a numerical range "1 to 100" includes both its lower limit "1" and upper limit "100". The same applies to the expression of other numerical ranges.

[0045] (Thermoplastic release film)

[0046] The thermoplastic release film of this embodiment is a release film used in the resin molding process of semiconductor devices to obtain the release properties of the cured encapsulating resin from the mold. The thermoplastic release film of this embodiment is characterized by containing at least a thermoplastic crystalline cyclic polyolefin and a polyolefin-based thermoplastic elastomer, and in dynamic viscoelasticity spectroscopy measurements, the minimum value E'1 of the storage modulus in the range of 80–150°C and the storage modulus E'2 at 175°C satisfy a specific relationship.

[0047] [Thermoplastic crystalline cyclic polyolefins]

[0048] Thermoplastic crystalline cyclic polyolefins can be appropriately selected from known materials, and there is no particular limitation on their type. By using thermoplastic crystalline cyclic polyolefins with high melting points, high heat resistance and mold release properties can be imparted without the use of fluoropolymer films. In the high-temperature resin molding process, wrinkle formation can be suppressed, good film transportability can be provided, and the appearance defects of the resin molded part caused by the use of fluoropolymer films can be suppressed.

[0049] Specific examples of thermoplastic crystalline cyclic polyolefins include cyclic olefins. More specifically, examples include polymers formed by ring-opening polymerization and hydrogenation of norbornene, and cyclic olefin monomer ring-opening metathesis polymers, but these are not particularly limited to. A single thermoplastic crystalline cyclic polyolefin can be used alone, or two or more can be used in any combination and proportion. By using cyclic olefins as thermoplastic crystalline cyclic polyolefins, high heat resistance and high mold release properties can be imparted.

[0050] Examples of cyclic olefin polymers (COPs) and cyclic olefin copolymers (COCs) include, for example, the polyolefin resins described in Japanese Patent Application Publication No. 5-317411 and Japanese Patent Application Publication No. 2014-068767, and these contents are incorporated herein by reference. It should be noted that commercially available cyclic olefin polymers (COPs) include, for example, ZEONEX (registered trademark) and ZEONOR (registered trademark) manufactured by Zeon Corporation of Japan, and Daikyo Resin CZ (registered trademark) manufactured by Daikyo Seiko Co., Ltd. Similarly, commercially available cyclic olefin copolymers (COCs) include, for example, APEL (registered trademark) manufactured by Mitsui Chemicals Co., Ltd., and TOPAS (registered trademark) manufactured by Topas Advanced Polymers Co., Ltd.

[0051] The melting point of the aforementioned thermoplastic crystalline cyclic polyolefin is not particularly limited. However, from the viewpoint of ensuring higher heat resistance and good dispersibility with polyolefin-based thermoplastic elastomers, a melting point of 250°C or higher is preferred, more preferably 255°C or higher, and even more preferably 260°C or higher. While there is no particular limitation on the upper limit, the target is 300°C or lower. It should be noted that, in this specification, the melting point refers to the melting peak temperature determined by differential scanning calorimetry (DSC) using a DSC vesta (manufactured by Rigaku) ​​at a heating rate of 10°C / min within a temperature range of 30–350°C.

[0052] The proportion of thermoplastic crystalline cyclic polyolefin can be appropriately set according to the required performance and is not particularly limited. From the viewpoints of mold followability, film transportability, and wrinkle generation, based on the total amount of resin solids contained in the thermoplastic release film, it is preferably 15 to 75% by mass, more preferably 20 to 75% by mass, further preferably 25 to 75% by mass, and particularly preferably 30 to 75% by mass.

[0053] [Polyolefin-based thermoplastic elastomers]

[0054] Polyolefin-based thermoplastic elastomers can be appropriately selected from known materials, and there are no particular limitations on their types. By using polyolefin-based thermoplastic elastomers, mold release properties and mold followability can be improved.

[0055] Examples of such polyolefin-based thermoplastic elastomers include ethylene-based thermoplastic elastomers; polypropylene-based thermoplastic elastomers; and compositions formed by mixing high-density polyethylene, medium-density polyethylene, low-density polyethylene, and other polyethylenes, as well as homopolymer polypropylene, atactic polypropylene, and other polypropylenes, as needed. Ethylene-based and propylene-based thermoplastic elastomers are preferred as polyolefin-based thermoplastic elastomers, with propylene-based elastomers being more preferred. It should be noted that "ethylene-based thermoplastic elastomer" refers to an elastomer with an ethylene monomer content of 50 mol% or more, and "polypropylene-based thermoplastic elastomer" refers to an elastomer with a propylene monomer content of 50 mol% or more.

[0056] Specific examples of polyolefin-based thermoplastic elastomers include linear or branched olefin polymers such as ethylene-α-olefin copolymers, propylene-α-olefin copolymers, and ethylene-propylene-diene copolymers, but are not particularly limited to these. Among these, ethylene-α-olefin copolymers and propylene-α-olefin copolymers are more preferred. It should be noted that an ethylene-α-olefin copolymer refers to a copolymer containing ethylene monomer units and α-olefin monomer units other than ethylene, and this ethylene-α-olefin copolymer also refers to a copolymer containing monomer units other than α-olefins. In addition, a propylene-α-olefin copolymer is a copolymer of propylene monomer units and α-olefin monomer units other than propylene (wherein, the "α-olefin monomer units" referred to herein also include ethylene), and this propylene-α-olefin copolymer is intended to include copolymers that further contain monomer units other than α-olefins. Examples of α-olefins include 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tetracene, 1-tetradecene, 1-pentadecadecene, 1-hexadecene, 1-heptadecene, 1-heptadecene, 1-octadecene, 1-nonadecadecene, 1-eicosene, 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 2-ethyl-1-hexene, and 2,2,4-trimethyl-1-pentene, but these are not specifically limited to these. Other monomeric units besides α-olefins include, for example, vinyl aromatic compounds such as styrene and polyene compounds. It should be noted that the monomer components of the above copolymers can be binary or ternary or higher multi-component systems, can be random copolymers or block copolymers, and can also be isotactic, atactic, syndiotactic, or a mixture thereof. Polyolefin thermoplastic elastomers can be used alone, or in any combination and proportion of two or more types.

[0057] Commercially available polyolefin thermoplastic elastomers include: MILASTOMER (registered trademark) manufactured by Mitsui Chemicals Co., Ltd.; "TAFMER (registered trademark) H" manufactured by Mitsui Chemicals Co., Ltd.; "TAFMER (registered trademark) A" manufactured by Mitsui Chemicals Co., Ltd.; "TAFMER (registered trademark) P" manufactured by Mitsui Chemicals Co., Ltd.; "EXCELLEN (registered trademark) FX" manufactured by Sumitomo Chemicals Co., Ltd.; "EXCELLEN (registered trademark) VL" manufactured by Sumitomo Chemicals Co., Ltd.; "Tafcelene (registered trademark)" manufactured by Sumitomo Chemicals Co., Ltd.; "Engage", "Affinity", and "Infuse" manufactured by Dow Chemical Co., Ltd.; and "Exact" manufactured by Exxon Mobil Co., Ltd. Trade names include "Vistamaxx" manufactured by Mobil Corporation, "LUCENE" manufactured by LG Chem Corporation, "Karnel" manufactured by Nippon Polyethylene Corporation, "Evolue P", "Evolue H", and "NEOZEX" manufactured by Prime Polymer Corporation, and "WELNEX" manufactured by Polypropylene Corporation of Japan; etc.

[0058] The melt flow rate (MFR) of polyolefin-based thermoplastic elastomers is not particularly limited. However, from the viewpoints of improving film transportability and demolding properties, and suppressing uneven thickness and wrinkles, it is more preferably 0.1 g / 10 min or more, further preferably 0.2 g / 10 min or more, particularly preferably 0.3 g / 10 min or more, more preferably 10 g / 10 min or less, further preferably less than 9.0 g / 10 min, particularly preferably less than 8.0 g / 10 min, and most preferably less than 7.0 g / 10 min. It should be noted that, in this specification, the melt flow rate of polyolefin-based thermoplastic elastomers refers to the value measured according to Method A, under condition M (230°C, 2.16 kg load) in JIS K7210:1999 "Test methods for melt mass flow rate (MFR) and melt volumetric flow rate (MVR) of plastics—thermoplastics".

[0059] The content ratio of the above-mentioned polyolefin thermoplastic elastomer can be appropriately set according to the required performance, and there is no particular limitation. From the viewpoints of mold followability, film transportability, and wrinkle generation, the total amount of resin solids contained in the thermoplastic release film is used as a basis, preferably 5 to 75% by mass, more preferably 5 to 70% by mass, further preferably 5 to 65% by mass, and particularly preferably 10 to 60% by mass.

[0060] [High melt tension polypropylene]

[0061] In addition to thermoplastic crystalline cyclic polyolefins and polyolefin-based thermoplastic elastomers, the thermoplastic release film of this embodiment may, as needed, contain high melt tension polypropylene. Generally, general-purpose polypropylene tends to have low melt tension due to its linear molecular structure. However, the high melt tension polypropylene used here exhibits higher melt tension than general-purpose polypropylene with the same melt flow rate, resulting in excellent balance with flowability and high strain curing properties. Therefore, by incorporating high melt tension polypropylene, uneven thickness and wrinkling of the thermoplastic release film can be suppressed. The high melt tension polypropylene is preferably a propylene-based polymer with a long-chain branched structure, having a melt tension of 3 to 30 g (230°C) and a melt flow rate of 0.9 g to 15 g / 10 min or less (based on JIS K7210:1999, 230°C, 2.16 kg load). Here, the propylene-based polymer can be a propylene homopolymer or a propylene copolymer. When the copolymer is a propylene copolymer, the comonomer is preferably at least one olefin selected from the group consisting of ethylene and α-olefins having 4 to 10 carbon atoms. In this case, the content of the comonomer in the propylene copolymer is preferably 0.1 to 20% by mass, more preferably 0.1 to 10% by mass, and even more preferably 0.1 to 3% by mass. From the viewpoint of heat resistance and rigidity, high melt tension polypropylene is preferably a propylene homopolymer. It should be noted that substances that are equivalent to both the above-mentioned polyolefin-based thermoplastic elastomers and high melt tension polypropylene are treated as high melt tension polypropylene in this specification and excluded from the above-mentioned polyolefin-based thermoplastic elastomers.

[0062] Here, the aforementioned long-chain branched structure refers to a branched structure formed by molecular chains with a main chain of tens or more carbon atoms and a molecular weight of hundreds or more, which is different from short-chain branches with a few carbon atoms formed by copolymerization with α-olefins such as 1-butene. Methods for introducing long-chain branched structures include, for example, methods using high-energy ionization radiation to form long-chain branches, methods using organic peroxides to form long-chain branches, and methods using metallocene catalysts to polymerize propylene polymers with long-chain branches. Furthermore, methods for investigating the presence of long-chain branches in propylene polymers can be performed using methods known in the art, without particular limitation. Examples include methods using melt tension, methods using the rheological properties of resins such as logarithmic strain in tensile viscosity measurements, calculations of the branching index based on the relationship between molecular weight and viscosity, and methods using... 13 Methods such as C-NMR.

[0063] From the perspective of suppressing uneven thickness and wrinkle formation, the melt tension of high melt tension polypropylene is more preferably 4g or more, further preferably 5g or more, particularly preferably 6g or more, more preferably 28g or less, and further preferably 26g or less. It should be noted that, in this specification, the melt tension of high melt tension polypropylene refers to a value measured under the following conditions. Here, the melt tension can be adjusted based on, for example, molecular weight Mw / Mn, the number of carbon atoms in the long chain, the number of branches in the long chain, and the melt flow rate.

[0064] [Conditions for determining melt tension]

[0065] Measuring device: Capillograph 1B manufactured by Toyo Seiki Co., Ltd.

[0066] Capillary tube: 2.0 mm in diameter, 40 mm in length

[0067] Cylinder diameter: 9.55mm

[0068] Piston extrusion speed: 20mm / min

[0069] Traction speed: 4.0 m / min

[0070] (Among them, in the case where the resin breaks due to excessive melt tension, the traction speed is reduced, and the measurement is performed at the highest traction speed that can be achieved.)

[0071] Temperature: 230℃

[0072] On the other hand, from the viewpoints of film transportability, suppression of thickness unevenness, and wrinkle formation, the melt flow rate of high melt tension polypropylene is more preferably 1.0 g / 10 min or more, further preferably 1.1 g / 10 min or more, more preferably 14 g / 10 min or less, and even more preferably 13 g / 10 min or less. Here, the melt flow rate can be adjusted according to, for example, the molecular weight distribution Mw / Mn, the number of carbon atoms in the long chain, the number of branches in the long chain, and the amount of hydrogen added during polymerization. It should be noted that, in this specification, the melt flow rate of high melt tension polypropylene refers to the value measured according to Method A, under condition M (230°C, 2.16 kg load), of JIS K7210:1999 "Test methods for melt mass flow rate (MFR) and melt volumetric flow rate (MVR) of plastics—thermoplastics".

[0073] Furthermore, as a preferred high melt tension polypropylene, examples include high melt tension polypropylene with an η0.3 / η3.0 ratio of 10 to 500 when the tensile viscosity at 190°C with a logarithmic strain of 0.3 is set as η0.3 and the tensile viscosity at 190°C with a logarithmic strain of 3.0 is set as η3.0. η0.3 / η3.0 is more preferably 15 to 450, and even more preferably 20 to 400. By using high melt tension polypropylene with η0.3 / η3.0 values ​​within these ranges, it is easier to obtain thermoplastic release films with excellent uniformity in terms of film transportability, suppression of thickness unevenness, and wrinkle formation. Here, η0.3 / η3.0 can be adjusted according to, for example, molecular weight Mw / Mn, number of carbon atoms in long chains, number of branches in long chains, melt flow rate, etc. In this specification, η0.3 / η3.0 refers to a value calculated from the tensile viscosity measured under the following conditions using the following method.

[0074] [Conditions for determining tensile viscosity]

[0075] Measuring apparatus: TA Instruments DHR-2

[0076] Measurement temperature: 190℃

[0077] Strain rate: 0.5 / sec

[0078] Method for preparing the test piece: compression molding

[0079] The test piece was 0.5 mm thick and 10 mm wide x 20 mm long.

[0080] The aforementioned high melt tension polypropylene can be obtained using known manufacturing methods, and the method is not particularly limited. Preferred methods include, for example, copolymerization of macromolecular monomers using one or more metallocene catalysts, such as those described in Japanese Patent Application Publication Nos. 2001-525460, 2009-275207, 2009-293020, 2009-299029, and 2009-57542, but are not specifically limited to these methods. Furthermore, commercially available high melt tension polypropylene products are already on the market, such as WAYMAX (registered trademark) manufactured by Nippon Polypropylene Co., Ltd. TM (MFX3, MFX6, MFX8, EX8000, EX6000, EX4000), Borealis's Daploy (registered trademark) HMS-PP (WB130HMS, WB135HMS, WB140HMS), etc.

[0081] The content ratio of the high melt tension polypropylene can be appropriately set according to the required performance, without particular limitation. From the viewpoints of mold followability, film transportability, and wrinkle generation, based on the total amount of resin solids contained in the thermoplastic release film, it is preferably 3 to 45% by mass, more preferably 3 to 40% by mass, further preferably 3 to 35% by mass, and particularly preferably 3 to 30% by mass.

[0082] Without unduly impairing the effects of the present invention, the thermoplastic release film of this embodiment may contain, in addition to the above-mentioned thermoplastic crystalline cyclic polyolefins and polyolefin-based thermoplastic elastomers, and even, if necessary, high melt tension polypropylene, other resin components such as acetate-based polymers, poly(meth)acrylic acid-based polymers, polyester-based polymers, polyethersulfone-based polymers, polysulfone-based polymers, polycarbonate-based polymers, polyamide-based polymers, polyimide-based polymers, polyolefin-based polymers, polyaryl ester-based polymers, polystyrene-based polymers, polyvinyl alcohol-based polymers, thermosetting resins, and thermoplastic resins. Furthermore, without unduly impairing the effects of the present invention, the thermoplastic release film of this embodiment may use additives known in the art, such as release modifiers like higher fatty acids with 10 to 25 carbon atoms, higher fatty acid esters, higher fatty acid amides, higher fatty acid metal salts, polysiloxanes, and fluororesins; colorants like dyes and pigments; organic fillers; inorganic fillers; antioxidants; heat stabilizers; light stabilizers; ultraviolet absorbers; flame retardants; antistatic agents; surfactants; rust inhibitors; defoamers; and may also contain fluorescent agents. Other resin components and additives may be used individually or in combination of two or more. Other resin components and additives may be included in the resin composition prepared, for example, during the film-making process of the thermoplastic release film. The content of other resin components and additives is not particularly limited, but from the viewpoint of molding processability and thermal stability, they are preferably 0.01 to 10% by mass, more preferably 0.1 to 7% by mass, and even more preferably 0.5 to 5% by mass, relative to the total amount of the thermoplastic release film.

[0083] From the perspective of suppressing the appearance defects of the resin molded part and improving versatility at a higher level, the thermoplastic release film of this embodiment is preferably halogen-free or low in halogens. From this point of view, the proportion of fluoropolymers containing a large amount of fluorine atoms (halogen atoms) is preferably 0.0 to 3.0% by mass, more preferably 0.0 to 1.0% by mass, and even more preferably 0.0 to 0.1% by mass.

[0084] The method for forming the thermoplastic release film in this embodiment is not particularly limited, but melt extrusion is preferred. As a preferred method, a resin composition containing the above-mentioned components can be extruded into a film shape using a melt extrusion film forming method, and then the melt-extruded film can be subjected to pressure and heat treatment as needed to obtain a melt-extruded film. In this case, the preparation of the resin composition can be carried out according to conventional methods, and there are no particular limitations. The above-mentioned components can be manufactured and processed by known methods such as mixing, melt mixing, granulation, extrusion molding, compression molding, or injection molding. It should be noted that when performing melt mixing, commonly used single-screw or twin-screw extruders, various kneaders, and other mixing devices can be used. When supplying the components to these melt mixing devices, the components can be pre-mixed using a mixing device such as a rotary drum or Henschel mixer. Furthermore, the obtained melt-extruded film can be directly used as an unstretched release film for semiconductor packaging processes. However, from the viewpoints of improving film strength, heat resistance, and adjusting film crystallinity, it can be subjected to uniaxial or biaxial heat stretching treatment and post-heat treatment (annealing treatment) as needed. From the viewpoints of improving film transportability and release properties, suppressing thickness unevenness, and preventing wrinkles, the thermoplastic release film of this embodiment is preferably a uniaxially stretched film or a biaxially stretched film, more preferably a biaxially stretched film. In addition, from the viewpoints of cost reduction, reuse, or recycling, the thermoplastic release film of this embodiment is preferably a single-layer film (non-laminated film).

[0085] The settings for melt extrusion can be appropriately set according to the type and composition of the resin composition used, the required properties of the target thermoplastic release film, etc., and there are no particular limitations. For example, the set temperature of the extruder barrel is preferably 230 to 300°C, and more preferably 250 to 2900°C.

[0086] The conditions for the heat stretching treatment can be appropriately set according to the type and composition of the resin composition used and the required properties of the target thermoplastic release film, and there are no particular limitations. For example, preferably, for melt-extruded films, it is preferable to stretch the film to 1.1 to 6.0 times its original length in the MD direction (Machine Direction) at 70 to 180°C to form a uniaxially stretched film, and then further stretch it to 1.1 to 6.0 times its original length in the TD direction (Transverse Direction) at 90 to 180°C, followed by heat treatment (heat setting) at 100 to 240°C for 1 to 600 seconds. In this case, simultaneous biaxial stretching can also be performed without sequential stretching. The stretch ratio is not particularly limited, but from the viewpoints of improving film transportability and demolding properties, suppressing thickness unevenness, and preventing wrinkles, the total stretch ratio in the MD direction * TD direction (when the stretch ratio in the MD direction is set as m and the stretch ratio in the TD direction is set as n, the stretch ratio expressed as m × n) is preferably 2.00 times or more, more preferably 4.00 times or more, and even more preferably 6.25 times or more. It should be noted that there is no particular upper limit, but the target is 30 times, preferably 20 times. Furthermore, during heat setting, methods known in the art can be used, such as contact heat treatment, non-contact heat treatment, etc., and the type is not particularly limited. For example, known equipment such as non-contact heaters, ovens, blow molding devices, hot rollers, cooling rollers, hot presses, and double-belt hot presses can be used for heat setting. At this time, if necessary, a release film or a porous film known in the art can be disposed on the surface of the stretched melt extruded film for hot pressing.

[0087] The conditions for post-heat treatment (annealing) can be appropriately set according to the type and composition of the resin composition used and the desired properties of the target thermoplastic release film, and are not particularly limited. For example, it is preferable to heat-treat the melt-extruded film or stretched melt-extruded film at 100–240°C for 1–600 seconds. This post-heat treatment can be performed using methods known in the art, such as contact heat treatment or non-contact heat treatment, and the type is not particularly limited. For example, known equipment such as non-contact heaters, ovens, blow molding devices, hot rollers, cooling rollers, hot presses, and double-belt hot presses can be used for post-heat treatment. At this time, if necessary, a release film or porous film known in the art can be disposed on the surface of the melt-extruded film or stretched melt-extruded film, and then hot pressing can be performed.

[0088] The thickness of the thermoplastic release film in this embodiment can be appropriately set according to the required performance and is not particularly limited. Considering operability, productivity, etc., it is preferably 1 μm to 600 μm, more preferably 5 μm to 500 μm, further preferably 10 μm to 300 μm, and particularly preferably 15 μm to 250 μm. It should be noted that in this specification, the thickness of the thermoplastic release film refers to the average value of four randomly selected points.

[0089] Here, the thermoplastic release film of this embodiment is characterized in that, in dynamic viscoelastic spectroscopy measurements, the lowest value E'1 of the storage modulus in the range of 80 to 150°C and the storage modulus E'2 at 175°C satisfy the following equations (1) and (2). When used in semiconductor packaging processes, a high storage modulus E'2 at the molding temperature (e.g., 175°C) is required as a requirement. This is taken into account factors such as improving flexibility at the molding temperature, suppressing wrinkle formation when mounted on the inner surface of the mold, and improving mold followability. Furthermore, based on the inventors' insights, it has been found that in blends of thermoplastic crystalline cyclic polyolefins and polyolefin-based thermoplastic elastomers (binary or higher), and further in blends of high melt tension polypropylene (ternary or higher), the storage modulus in the 80–150°C range can be significantly reduced. When the minimum value E'1 of the storage modulus in this 80–150°C range is too low, the resin composition becomes prone to flow, which has adverse effects on thickness accuracy, film transportability, mold followability, wrinkle formation, and poor appearance of the resin molded portion. Moreover, it has been found that in the thermoplastic release film of this embodiment, when the minimum value E'1 of the storage modulus in the 80–150°C range and the storage modulus E'2 at 175°C satisfy the following formulas (1) and (2), the aforementioned properties that are in a trade-off relationship can be maintained to a higher degree. In addition, in the above-mentioned dynamic viscoelasticity spectrum measurement, it is more preferable that the above-mentioned E'2 satisfies the following formula (3).

[0090] 10MPa≤E'1≤100MPa (1)

[0091] E'1≥E'2 (2)

[0092] 10MPa≤E'2≤100MPa (3)

[0093] In the above-mentioned range, the minimum value E'1 of the storage modulus in the range of 80–150°C is preferably 10 MPa to 90 MPa, more preferably 10 MPa to 80 MPa, and even more preferably 15 MPa to 75 MPa. Furthermore, the storage modulus E'2 at 175°C is preferably 10 MPa to 90 MPa, more preferably 10 MPa to 80 MPa, and even more preferably 10 MPa to 70 MPa. It should be noted that the minimum value E'1 of the storage modulus of the thermoplastic release film in the range of 80–150°C and the storage modulus E'2 at 175°C can be appropriately adjusted according to the desired properties of the target thermoplastic release film. For example, the storage modulus can be adjusted by changing the types of components used, the proportion of the resin composition, and the processing conditions of heating, stretching, and / or post-heating. Additionally, the storage modulus can also be adjusted by stretching treatment or heat treatment.

[0094] Furthermore, the thermoplastic release film of this embodiment can be appropriately set according to the required performance, without particular limitation. From the viewpoint of improving softness to suppress the generation of wrinkles when installed on the inner surface of the mold and improving mold followability, in the dynamic viscoelastic spectrum measurement, the loss tangent Tanδ at 175°C is preferably in the range of 0.05 to 0.20, and more preferably in the range of 0.05 to 0.18.

[0095] In this specification, the storage modulus and loss tangent Tanδ of the thermoplastic release film refer to values ​​measured at 1 Hz using a dynamic viscoelastic apparatus RSA-3 (manufactured by TA Instruments) according to JIS K 7244-4. For other details, the measurement conditions described in the examples below are as follows.

[0096] Furthermore, for the thermoplastic release film of this embodiment, from the viewpoints of improving film transportability and release properties, suppressing thickness unevenness, and reducing wrinkle formation, the heat of cold crystallization is preferably 10.0 J / g or less, more preferably 7.0 J / g or less, further preferably 5.0 J / g or less, and particularly preferably 3.0 J / g or less in differential scanning calorimetry (DSC) measurements. It should be noted that there is no particular limitation on the lower limit value; it is acceptable as long as it is 0 J / g or more (above the detection limit). Although the thermoplastic release film of this embodiment uses a crystalline polymer (i.e., thermoplastic crystalline cyclic polyolefin), a polyolefin-based thermoplastic elastomer, and, if necessary, high melt tension polypropylene, the heat of cold crystallization is low as described above. Crystallization occurs sufficiently during film formation, resulting in a film whose softness is not excessively compromised. It possesses both high heat resistance and good mold followability. During the high-temperature resin molding process, film transportability is good and wrinkle formation is reduced. Furthermore, there is a tendency to reduce the appearance defects of the resin-molded portion caused by the fluoropolymer film. It should be noted that the heat of cold crystallization of thermoplastic release films can be adjusted appropriately according to the required properties of the target thermoplastic release film. For example, the heat of cold crystallization can be adjusted by changing the types of components used, the proportion of the resin composition, the heating and stretching, and the post-heating treatment conditions.

[0097] In this specification, the heat of cold crystallization of the thermoplastic release film is a value calculated based on thermal analysis results obtained from a sample taken from the thermoplastic release film using a differential scanning calorimeter according to JIS K7121:2012. For other details, the measurement conditions described in the examples below are as follows.

[0098] The thermoplastic release film of this embodiment, by adopting the above-described structure, not only has a lower cost and achieves halogen-free properties, excellent thickness accuracy, and good release properties, but also exhibits good film transportability and mold following properties during high-temperature resin molding processes, resulting in fewer wrinkles and suppressing the occurrence of appearance defects in the resin-molded portion. Therefore, the thermoplastic release film of this embodiment is suitable for use as a release film in semiconductor packaging processes for obtaining the release properties between the cured encapsulation resin and the mold during the resin molding process of semiconductor devices. In particular, since the thermoplastic release film of this embodiment suppresses the generation of wrinkles and the occurrence of appearance defects in the resin-molded portion, it fully meets the performance requirements of thermoplastic release films for compression molding processes in semiconductor packaging processes that require more precise molding conditions than conventional transfer molding methods. In addition, the thermoplastic release film of this embodiment can be subjected to surface treatments such as sandblasting, wet sandblasting, and hot embossing as needed. By utilizing these surface treatments to impart the desired surface texture, it is possible to further improve mold release properties, film transportability, and mold followability, and to further suppress the generation of wrinkles and poor appearance of resin molded parts.

[0099] The thermoplastic release film of this embodiment is suitable for use as a release film in the resin encapsulation process of semiconductor elements in the manufacture of semiconductor devices. There are no particular limitations on the method of resin encapsulating semiconductor elements using the thermoplastic release film of this embodiment. When resin encapsulating semiconductor elements inside a molding die, the thermoplastic release film of this embodiment can be disposed on the inner surface of the molding die. For example, it is preferable to use known resin molding methods such as transfer molding and compression molding. In particular, the compression molding method is a resin encapsulation method in which resin is loaded into the mold cavity, melted, and then the mold is closed to seal the semiconductor element with the molten resin. Since there is almost no resin flow, the impact on the chip and leads can be minimized, thus enabling lead thinning. As a method suitable for the minimization, thinning, high integration, high productivity, and cost reduction process requirements of packaging in recent years, its application is being promoted. In the compression method, since gates, runners, etc., are not required as in the transfer method, the resin utilization efficiency is basically 100%, thus also resulting in cost reduction and a decrease in waste.

[0100] Therefore, the thermoplastic release film of this embodiment is particularly useful in compression molding of resins. One example of its use is as follows: Figure 1 As shown, using a mold D having an upper mold D1 and a lower mold D2, with the thermoplastic release film 100 positioned on the inner surface of the lower mold D2, a vacuum is applied as needed to seal the thermoplastic release film 100 against the inner surface or parting surface of the lower mold D2. Molding resin M is then poured into the cavity C of the lower mold D2. After heating as needed to melt or liquefy the molding resin M, the upper mold D1 and lower mold D2 are closed, sealing (or pressing or compressing) the substrate 11 carrying the semiconductor element against the molding resin M. Heating and pressurizing are then applied as needed to resin encapsulate the semiconductor element. It should be noted that the thermoplastic release film 100 only needs to be positioned on at least one side of the inner surface of the upper mold D1 or the inner surface of the lower mold D2. The molding conditions at this time can be performed according to conventional methods without special limitations. For example, the mold temperature (molding temperature) can be 160–190°C, the molding pressure can be 5–12 MPa, and the molding time can be approximately 1–600 seconds. By having a thermoplastic release film 100 present during resin molding, contact between the molding resin M and the inner surface of the mold D can be avoided, making it easy to demold the resin-encapsulated substrate 11 from the mold D. It should be noted that the substrate 11, which is the object of resin encapsulation, can be, for example, a multilayer printed circuit board or a flexible printed circuit board, but its type is not particularly limited.

[0101] Example

[0102] The following examples and comparative examples illustrate the features of the present invention in more detail, but the present invention is not limited to these examples. That is, the materials, amounts, proportions, processing contents, processing order, etc., shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Furthermore, the various manufacturing conditions and evaluation results values ​​in the following examples are intended as preferred upper or lower limits in the implementation of the present invention, and the preferred numerical range can also be a range defined by a combination of the aforementioned upper or lower limits and the values ​​of the following examples or the values ​​of the examples themselves.

[0103] The materials used in the examples and comparative examples are as follows.

[0104] (Resin A)

[0105] (A-1) Thermoplastic crystalline cyclic polyolefin, manufactured by Zeon Corporation, Japan, "ZEONEX (registered trademark) C2420", melting temperature: 263℃

[0106] (Resin B)

[0107] (B-1) Polyolefin elastomer resin, trade name "Vistamaxx (registered trademark) Vistamacxx 3020FL" of Exxon Mobil Corporation, melt flow rate: 2.4 g / 10 min (based on JIS K7210:1999, 230°C, 2.16 kg load).

[0108] (Resin C)

[0109] (C-1) High melt tension polypropylene, manufactured by Polypropylene Corporation of Japan, "WAYMAX (registered trademark) MFX8", melt tension (230℃): 25g, melt flow rate: 1.1g / 10min (based on JIS K7210:1999, 230℃, 2.16kg load).

[0110] (Biaxially stretched PET film)

[0111] (D-1) Polyethylene terephthalate film, manufactured by Toray Industries, Inc. "Lumirror (registered trademark) #350-S10"

[0112] (Example 1)

[0113] Resin A and Resin B, dried at 80°C for more than 8 hours, were dry-blended according to the composition and proportions listed in Table 1. The resulting blend was melt-blended using a co-rotating, vented twin-screw extruder heated to 280°C. The resulting wire bundle was cut using a granulator to prepare a resin composition (blended sheet). The obtained resin composition was dried at 80°C for more than 8 hours using a hopper dryer or similar equipment. It was then fed into the hopper of an extruder heated to 280°C for melt-blending and co-extruded into a film from the T-die at the front of the extruder. After cooling, an unstretched melt-extruded film with a thickness of 500 μm was obtained. The obtained unstretched melt-extruded film was biaxially stretched at 130°C by 2.5 times in the MD direction and 2.5 times in the TD direction (overall ratio: 6.25 times). It was then heat-set at 130°C for 2 minutes to obtain the thermoplastic release film of Example 1 with an average thickness of 120 μm.

[0114] (Examples 2-11)

[0115] Except for changing the composition and proportions as recorded in Table 1, the same procedure was followed as in Example 1 to obtain the thermoplastic release films of Examples 2 to 11.

[0116] (Example 12)

[0117] The stretch ratio was set to 1.5 times in the MD direction and 1.5 times in the TD direction (overall ratio: 2.25 times), and heat setting was omitted. Otherwise, the process was carried out in the same manner as in Example 4, resulting in the thermoplastic release film of Example 12 with an average thickness of 240 μm.

[0118] (Example 13)

[0119] The stretch ratio was set to 1.5 times in the MD direction and 1.5 times in the TD direction (overall ratio: 2.25 times), and the heat setting time was changed to 1 minute. Otherwise, the process was carried out in the same manner as in Example 4, and the thermoplastic release film of Example 13 with an average thickness of 240 μm was obtained.

[0120] (Example 14)

[0121] Except for changing the thickness of the unstretched melt-extruded film to 50 μm, the process was carried out in the same manner as in Example 4 to obtain the thermoplastic release film of Example 14 with an average thickness of 5 μm.

[0122] (Example 15)

[0123] Except for changing the thickness of the unstretched melt-extruded film to 100 μm, the process was carried out in the same manner as in Example 4, resulting in the thermoplastic release film of Example 15 with an average thickness of 20 μm.

[0124] (Example 16)

[0125] The stretch ratio was changed to 1.3 times in the MD direction and 1.3 times in the TD direction (overall stretch ratio: 1.69 times), otherwise the same procedure as in Example 4 was performed to obtain the thermoplastic release film of Example 16 with an average thickness of 280 μm.

[0126] (Example 17)

[0127] The stretch ratio was changed to 1.1 times in the MD direction and 1.1 times in the TD direction (overall stretch ratio: 1.21 times), otherwise the same procedure as in Example 4 was performed to obtain the thermoplastic release film of Example 17 with an average thickness of 400 μm.

[0128] (Comparative Example 1)

[0129] Except for omitting the stretching and heat setting processes, the process was carried out in the same manner as in Example 4, resulting in a thermoplastic release film of Comparative Example 1 with an average thickness of 500 μm.

[0130] (Comparative Example 2)

[0131] Except for changing the composition and proportions as described in Table 1, the process was carried out in the same manner as in Example 4, and a thermoplastic release film of Comparative Example 2 with an average thickness of 120 μm was obtained.

[0132] (Comparative Example 3)

[0133] Except for changing the composition and proportions as described in Table 1, and changing the stretching temperature and heat setting temperature to 140°C, the process was carried out in the same manner as in Example 4, and a thermoplastic release film of Comparative Example 3 with an average thickness of 120 μm was obtained.

[0134] (Refer to Example 1)

[0135] As a reference example 1, the physical properties of a biaxially stretched PET film with an average thickness of 350 μm (D-1) were measured.

[0136] The conditions for measuring the properties of each release film are as follows.

[0137] (Storage modulus E' and loss factor Tanδ)

[0138] Apparatus: RSA-3 dynamic viscoelastic apparatus (manufactured by TA Instruments)

[0139] Measurement conditions: Tensile mode

[0140] Vibration frequency: 1Hz

[0141] Temperature measurement: The temperature was increased from 23°C to 200°C at a rate of 5°C / minute.

[0142] Measurement direction: Length direction of the membrane (membrane transport direction)

[0143] Evaluation item: Minimum value of energy storage modulus E'1 in the range of 80~150℃

[0144] Storage modulus E'2 at 175℃

[0145] Loss factor Tanδ at 175℃

[0146] [Heat of cold crystallization]

[0147] Apparatus: Differential Scanning Calorimetry (DSC vesta (manufactured by Rigaku Corporation))

[0148] Temperature measurement: The temperature is increased from 23°C to 200°C at a rate of 5°C / minute.

[0149] Sample quantity: 5 mg for each sample.

[0150] Evaluation item: Heat of cold crystallization

[0151] [Average Thickness]

[0152] The thickness was randomly measured at 4 points, and the average value was taken.

[0153] The performance evaluation of the obtained release films is as follows.

[0154] (Thickness accuracy)

[0155] Thickness was randomly measured at 30 points in each obtained membrane. The membrane thickness deviation was calculated using the average value and standard deviation of the measurements, and evaluated based on the following criteria.

[0156] Film thickness deviation (%) = (standard deviation / average value) × 100

[0157] Excellent (◎): Film thickness deviation less than 3%

[0158] Good (○): Film thickness deviation is 3% or more and less than 8%.

[0159] Poor (×): Film thickness deviation is 8% or more.

[0160] (Mold release properties)

[0161] A 25cm x 25cm square polyimide film (trade name: Upilex 125S, manufactured by Ube Industries, Inc., 125μm thick) was placed on a 15cm x 15cm square metal plate (3mm thick). A 20cm x 20cm square polyimide film (0.2mm thick) with a 10cm x 8cm rectangular hole in the center was then placed on top as a spacer. 3g of semiconductor packaging epoxy granules (trade name: SUMIKON EME G770H type F ver.GR, manufactured by SUMITOMO BAKELITE) were placed near the center of the hole. A 20cm x 20cm square release film was then placed on top, with the first side facing down (epoxy resin side). Finally, a 25cm x 25cm square metal plate (3mm thick) was placed on top to create a laminated sample. Then, the laminated sample was placed in a press heated to 180°C, preheated for 30 seconds, and then pressed for 5 minutes at a pressure of 10 MPa to cure the epoxy resin. The laminated sample was then removed, the metal plate and polyimide film were removed, and the sample was allowed to return to room temperature. The front end of the release film was held, and the load at a peel angle of 90° from the epoxy resin was measured using a standard digital force gauge ZTS-5N (IMADA).

[0162] Excellent (◎): Peel load less than 1.0N

[0163] Good (○): Peel load is 1.0 or higher and less than 5.0 N.

[0164] Poor (×): Peel load is above 5.0N (cannot be measured above 10N)

[0165] (Molding test)

[0166] like Figure 1 As shown, under a tension of 1 MPa between the upper and lower molds of the semiconductor packaging compression molding apparatus PMC1040, a thermoplastic release film is pulled out from a roll blank and placed on it. The thermoplastic release film is then vacuum-adsorbed onto the parting surface of the lower mold and cut to a certain length. A semiconductor element fixed to the substrate is placed on the parting surface of the upper mold. Next, molding resin M is introduced into the cavity C of the lower mold, which is protected by the thermoplastic release film on the parting surface. The mold temperature is heated to 180°C, and the molding resin M is melted or liquefied. The upper and lower molds are then closed, and air is extracted from the vacuum adsorption holes at the periphery of the cavity using a vacuum pump. The mixture is sealed to a specified final depth and clamping force for a specified time to perform resin encapsulation (compression molding) of the semiconductor element fixed to the substrate. The resin-encapsulated substrate (semiconductor package) is then demolded from the mold and the thermoplastic release film and removed. The performance of each thermoplastic release film at this time is evaluated according to the following criteria.

[0167] <Encapsulation Requirements>

[0168] Mold temperature: 175℃

[0169] Cavity size: 220mm × 55mm

[0170] Final cavity depth: 0.5mm

[0171] Curing resin: SUMIKON EME G770H type F Ver.GR (manufactured by SUMITOMO BAKELITE)

[0172] Vacuum level when following the cavity surface: -85kPa

[0173] Vacuum degree during bubble removal of curing resin: -80kPa

[0174] Time for removing air bubbles from cured resin: 10 seconds

[0175] Clamping time: 120 seconds

[0176] Molding pressure: 8.0 MPa

[0177] (Membrane transport properties)

[0178] The properties of the thermoplastic release film are visually observed during vacuum adsorption after it is extracted from the coil blank and transported to the parting surface of the mold. The following criteria are used to make the judgment.

[0179] Excellent (3): The thermoplastic release film can be handled without stretching due to the heat of the mold.

[0180] Good (2): The thermoplastic release film stretches slightly due to the heat of the mold.

[0181] Poor (1): The thermoplastic release film stretches due to the heat of the mold and cannot be transported.

[0182] (Mold following)

[0183] Excellent (3): There are absolutely no resin defects on the semiconductor package.

[0184] Good (2): There is a partial resin defect at the end of the semiconductor package.

[0185] Poor (1): The thermoplastic release film does not follow the mold and cannot be vacuum-adsorbed.

[0186] (Wrinkles, tears, bite-in)

[0187] Excellent (3): The thermoplastic release film was completely free of wrinkles and cracks.

[0188] Good (2): The thermoplastic release film has slight wrinkles but no cracks.

[0189] Poor (1): The thermoplastic release film has multiple wrinkles or is cracked.

[0190] [Table 1]

[0191]

[0192] Figure 2 The results of dynamic viscoelastic spectra measurements of the release films of Example 4 and Comparative Example 1 are shown.

[0193] Industrial availability

[0194] The thermoplastic release film of the present invention has a relatively low cost, is halogen-free, and has excellent thickness accuracy and release properties. Moreover, it has good film handling and mold following properties during high-temperature molding and produces fewer wrinkles, which can reduce the occurrence of appearance defects in the resin molded part. Therefore, it can be widely and effectively used as a release film for semiconductor packaging processes in the resin molding process of semiconductor components, especially as a release film for semiconductor packaging processes in compression molding, which can be utilized particularly effectively.

[0195] Explanation of reference numerals in the attached figures

[0196] 100 thermoplastic release film

[0197] 11. Substrate with semiconductor components mounted on it

[0198] C-cavity

[0199] D mold

[0200] D1 Upper Mold

[0201] D2 Lower Mold

[0202] M molding resin

Claims

1. A thermoplastic release film for semiconductor packaging processes, comprising at least a thermoplastic crystalline cyclic polyolefin and a polyolefin-based thermoplastic elastomer. In dynamic viscoelastic spectroscopy measurements, the minimum value of the storage modulus E'1 in the range of 80–150 °C and the storage modulus E'2 at 175 °C satisfy the following equations (1) and (2): 10MPa≤E'1≤100MPa (1) E'1≥E'2 (2).

2. The thermoplastic release film for semiconductor packaging processes as described in claim 1, wherein, In the dynamic viscoelastic spectrum determination, E'2 satisfies the following equation (3): 10MPa≤E'2≤100MPa (3).

3. The thermoplastic release film for semiconductor packaging processes as described in claim 1, wherein, Contains 15-75% by mass of the thermoplastic crystalline cyclic polyolefin and 5-75% by mass of the polyolefin-based thermoplastic elastomer.

4. The thermoplastic release film for semiconductor packaging processes as described in claim 3, wherein, It also contains 3-45% by mass of high melt tension polypropylene.

5. The thermoplastic release film for semiconductor packaging processes as described in claim 4, wherein, The high melt tension polypropylene comprises a propylene polymer with a long-chain branched structure having a melt tension (230°C) of 3 to 30 g and a melt flow rate (based on JIS K7210:1999, 230°C, 2.16 kg load) of less than 0.9 g to 15 g / 10 min.

6. The thermoplastic release film for semiconductor packaging processes as described in claim 1, wherein the heat of cold crystallization is below 5.0 J / g in differential scanning calorimetry.

7. The thermoplastic release film for semiconductor packaging process as described in claim 1, having a film thickness of 10 μm or more and 300 μm or less.

8. The thermoplastic release film for semiconductor packaging processes as described in claim 1, wherein, The polyolefin-based thermoplastic elastomer comprises one or more selected from the group consisting of ethylene-α-olefin copolymers, propylene-α-olefin copolymers, and ethylene-propylene-diene copolymers.

9. The thermoplastic release film for semiconductor packaging processes as described in claim 1, wherein, The thermoplastic crystalline cyclic polyolefin has a melting point of 250°C or higher.

10. A method for manufacturing electronic components, comprising at least the following steps: In the preparation step, the thermoplastic release film for semiconductor packaging process according to any one of claims 1 to 9 is disposed on the inner surface of the mold of the packaging apparatus, wherein, The encapsulation apparatus is an encapsulation apparatus that encapsulates part or all of a semiconductor element arranged on a substrate in a mold with resin. The process of injecting resin into the mold in which the thermoplastic release film for the semiconductor packaging process is disposed; The encapsulation process involves closing the mold to seal the semiconductor element with the resin, thereby encapsulating part or all of the semiconductor element with resin. as well as The demolding process involves peeling the thermoplastic release film used in the semiconductor packaging process from the mold.

11. The method for manufacturing an electronic component as claimed in claim 10, wherein, The substrate is a multilayer printed wiring board and / or a flexible printed wiring board.

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