Mold release film, method for its production and method for producing a semiconductor package

Abstract

Mold release film, characterized in that it comprising a first thermoplastic resin layer, a second thermoplastic resin layer, and an intermediate layer arranged between the first thermoplastic resin layer and the second thermoplastic resin layer, wherein The first thermoplastic resin layer and the second thermoplastic resin layer each have a storage elasticity modulus at 180 °C of 10 to 300 MPa, wherein the difference in the storage elasticity modulus at 25 °C between these is at most 1200 MPa and their thicknesses are from 12 to 50 µm. the intermediate layer comprises a layer containing a polymeric antistatic agent, and the first thermoplastic resin layer comprises one or more thermoplastic polymers and all thermoplastic polymers included in the first thermoplastic resin layer are fluoroolefin polymers.

Description

TECHNICAL AREA

[0001] The present invention relates to a mold release film which is to be arranged on a cavity surface of a mold in a method for producing a semiconductor housing by arranging a semiconductor element in the mold and encapsulating it with a curable resin to form a resin encapsulation section, a method for producing the mold release film and a method for producing a semiconductor housing using the mold release film. STATE OF THE ART

[0002] A semiconductor chip is typically encapsulated with a resin to shield and protect it from the outside air and mounted on a substrate as a molded product called a package. A curable resin, such as a thermosetting resin like epoxy resin, is used to encapsulate the semiconductor chip. One known encapsulation method for a semiconductor chip is injection molding or compression molding, in which a substrate bearing a mounted semiconductor chip is positioned so that the semiconductor chip is located at a predetermined position within the cavity of a mold. A curable resin is then injected into the cavity and cured.

[0003] Up to now, a package has been formed as a single housing component for each chip, connected via a sprue that serves as a flow path for a curable resin. In such cases, improved separation of the package from the mold is often achieved by adjusting the mold structure, adding a release agent to the curable resin, and so on. On the other hand, due to the need for miniaturization or multi-pin modification of packages, BGA-type or QFN-type packages, and furthermore, wafer-level CSP (WL-CSP) packages, are becoming increasingly common. For the QFN type, a mold release film is frequently applied to the cavity surface of the mold to ensure spacing and prevent resin buildup at the connection point, and to improve separation of the package from the mold in both the BGA and WL-CSP types.

[0004] The application of the mold release film to the cavity surface of the mold is typically accomplished by unwinding a long mold release film, wound in a superimposed state, from a reel, feeding the mold release film in a state where it is drawn through the unwind and rewind reels, and drawing the mold release film to the cavity surface by vacuum. Furthermore, a mold release film that has been pre-cut to a small size to fit the mold has also recently been provided (Patent Document 1).

[0005] A resin film is typically used as a mold release agent. However, such a mold release agent has a problem in that it is easily electrically charged. For example, in a case where a mold release agent is used by unwinding, static electricity is likely to be generated when the mold release agent is removed, and foreign materials, such as dust, etc., present in the manufacturing atmosphere are likely to be deposited on the charged mold release agent, causing mold anomalies (burr formation, foreign material deposition, etc.) of packages and mold contamination. In particular, the number of devices using granular resins as encapsulators for semiconductor chips is increasing (e.g.,Patent document 2), and therefore the shape anomalies and mold tool contamination caused by the deposition of dusts generated from the granulated resins are no longer ignored.

[0006] Furthermore, in recent years, with a view to thinning the package or improving heat dissipation properties, a package in which a semiconductor chip undergoes flip-chip bonding has been increasingly used, exposing the back side of the chip. This process step is referred to as the molded underfill (MUF) step. In the MUF step, encapsulation is carried out in a state where the mold release film and the semiconductor chip are in direct contact to protect and mask the semiconductor chip (e.g., patent document 3). If the mold release film becomes slightly charged, there is a concern that the semiconductor chip could be damaged by the charging and discharging during the removal process.

[0007] As a countermeasure, for example, (1) a method for eliminating electrostatic charging by blowing ionized air onto a mold release film between electrodes to which a high voltage is applied before the mold release film is transported into the mold (patent document 4), (2) a method for reducing the surface resistance of a mold release film by including carbon black (patent document 5), or (3) a method for applying an antistatic agent to a base material forming a mold release film, and furthermore for applying and crosslinking a crosslinkable acrylic adhesive to provide a release layer in the mold release film (patent documents 6 and 7) has been proposed.

[0008] US 2011 / 0133362 A1 describes a mold release film for the production of a semiconductor resin packing and a method for producing a semiconductor resin packing using the same. US 2010 / 0096772 A1 describes a release film for semiconductor resin molds. JP 2013-084873 A describes an adhesive composition, a release tape for an underfill molding process, and a release tape that uses this composition. DOCUMENTS ON THE STATE OF TECHNICAL PATENT DOCUMENTS Patent Document 1: JP 2009-272398 A Patent Document 2: JP 2008-279599 A Patent Document 3: JP 2013-123063 A Patent Document 4: JP 2000-252309 A Patent Document 5: JP 2002-280403 A Patent Document 6: JP 2005-166904 A Patent Document 7: JP 2013-084873 A REVELATION OF THE INVENTIONAL PROBLEM

[0009] However, in the method (1) although the electrical charge of the mold release film can be eliminated, there is a tendency to increase the risk of dust being picked up from the air and it is not possible to prevent charging and discharging at the time of removal.

[0010] In method (2), if soot is included in an amount that sufficiently reduces the surface resistance, it is likely that soot will be desorbed, which presents a problem in that desorbed soot will contaminate the molding tool.

[0011] In method (3), a crosslinkable acrylic adhesive is applied to one side of the base material, which makes it likely that the mold release film will become wavy unless the base material has certain degrees of thickness and modulus of elasticity. If the mold release film becomes wavy, a situation may arise at the time of adsorption of the mold release film to the mold where it is not well adsorbed to the mold. In particular, as described in patent document 1, if a device for feeding a short mold release film to the mold is used, the problem of waviness becomes considerable.A release film containing a thick base material with a high modulus of elasticity may not become wavy, however, such a release film has insufficient mold conformability and cannot be used in applications where mold conformability is required.

[0012] An object of the present invention is to provide a mold release film which does not simply become electrically charged or wavy, which does not contaminate a mold and which has excellent mold conformability, a method for producing it and a method for producing a semiconductor package using the mold release film. SOLUTION TO THE PROBLEM

[0013] The present invention provides a mold release film, a method for its production and a method for producing a semiconductor package, which have the following structure [1] to

[10] . [1] Mold release film, characterized in that it comprising a first thermoplastic resin layer, a second thermoplastic resin layer and an intermediate layer arranged between the first thermoplastic resin layer and the second thermoplastic resin layer, wherein The first thermoplastic resin layer and the second thermoplastic resin layer each have a storage elasticity modulus at 180 °C of 10 to 300 MPa, wherein the difference in the storage elasticity modulus at 25 °C between these is at most 1200 MPa and their thicknesses are from 12 to 50 µm. the intermediate layer comprises a layer containing a polymeric antistatic agent, and the first thermoplastic resin layer comprises one or more thermoplastic polymers and all thermoplastic polymers included in the first thermoplastic resin layer are fluoroolefin polymers. [2] Mold release film according to [1], wherein the intermediate layer is an intermediate layer comprising a layer containing a polymeric antistatic agent and an adhesive layer formed from an adhesive that does not contain a polymeric antistatic agent, or an adhesive layer containing a polymeric antistatic agent. [3] Mold release film according to [1] or [2], wherein both the first thermoplastic resin layer and the second thermoplastic resin layer do not contain an inorganic additive. [4] Mold release film according to one of [1] to [3], wherein the peel strength between the first thermoplastic resin layer and the second thermoplastic resin layer, measured at 180 °C according to JIS K6854-2, is at least 0.3 N / cm. [5] Mold release film according to [1] to [4], wherein the surface resistance of the layer containing a polymeric antistatic agent is at most 10 10 Ω / □ is. [6] Mold release film according to one of [1] to [5], wherein the waviness measured by the following measurement method is at most 1 cm: (Method for measuring waviness) At 20 to 25 °C, a square-shaped mold release film of 10 cm x 10 cm is left on a flat metal plate for 30 seconds, the maximum height (cm) of the section of the mold release film lifted from the metal plate is measured and the measurement is used as the waviness. [7] Mold release film according to one of [1], [2] and [4] to [6], wherein the first thermoplastic resin layer comprises at least one selected from the group consisting of an inorganic additive and an organic additive, wherein the inorganic additive is selected from the group consisting of carbon black, silicon dioxide, titanium oxide, cerium oxide, aluminum cobalt oxide, mica and zinc oxide, and wherein the organic additive is selected from the group consisting of silicone oil and metal soap. [8] Method for manufacturing a semiconductor package comprising a semiconductor element and a resin encapsulation section formed from a curable resin for encapsulating the semiconductor element, characterized in that it a step of arranging a mold release film, as defined in [1] to [7], on a surface of a mold tool which is to be in contact with a curable resin, wherein the second thermoplastic resin layer is in contact with the mold tool, a step of arranging a substrate, which has a semiconductor element mounted on it, in the mold tool, and filling a space in the mold tool with a curable resin followed by curing to form a resin encapsulation section, thereby obtaining an encapsulated body which has the substrate, the semiconductor element and the resin encapsulation section, and includes a step of separating the encapsulated body from the mold. [9] Method for producing a semiconductor package according to [8], wherein in the step of obtaining an encapsulated body a part of the semiconductor element is in direct contact with the separating film.

[10] A method for producing a mold release film, comprising a step of dry lamination of a first film to form a first thermoplastic resin layer and a second film to form a second thermoplastic resin layer using an adhesive, characterized in that the storage elasticity modulus E1' (MPa), the thickness T1 (µm), the width W1 (mm) and the tensile force F1 (N) exerted on it at the dry lamination temperature t (°C) of one of the first and second films and the storage elasticity modulus E2' (MPa), the thickness T2 (µm), the width W2 (mm) and the tensile force F2 (N) exerted on it at the dry lamination temperature t (°C) of the other film satisfy the following formula (I), 0.8≤(E1'×T1×W1)×F2} / {(E2'×T2×W2)×F1}≤1.2 where the storage elasticity modulus E1' (180) and E2' (180) at 180 °C is from 10 to 300 MPa, the difference in the storage elasticity modulus at 25 °C, i.e. |E1' (25) - E2' (25)|, is at most 1200 MPa, and T1 and T2 are each from 12 to 50 (µm), and the first thermoplastic resin layer comprises one or more thermoplastic polymers and all thermoplastic polymers included in the first thermoplastic resin layer are fluoroolefin polymers. ADVANTAGEOUS EFFECTS OF THE INVENTION

[0014] The mold tool release film of the present invention does not simply become electrically charged or wavy, does not contaminate the mold tool, and exhibits excellent mold tool conformability.

[0015] According to the method for producing a mold release film of the present invention, a mold release film can be produced which does not simply become electrically charged or wavy, does not contaminate the mold and has excellent mold conformability.

[0016] According to the method for manufacturing a semiconductor package of the present invention, difficulties caused by charging and discharging at the time of detachment of the mold release film can be avoided, such as the deposition of foreign materials on the charged mold release film, shape anomalies of the semiconductor package or associated mold contamination, destruction of the semiconductor chip due to discharge from the mold release film, etc. Furthermore, the adsorption of the mold release film can be carried out satisfactorily. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a schematic cross-sectional view of a first embodiment of the mold release film of the present invention. Fig. Figure 2 is a schematic cross-sectional view of an example of the semiconductor package obtainable by the method for manufacturing a semiconductor package of the present invention. Fig. Figure 3 is a schematic cross-sectional view of another example of the semiconductor package obtainable by the method for manufacturing a semiconductor package of the present invention. Fig. Figure 4 is a schematic cross-sectional view showing a step (α3) in the first embodiment of the method for manufacturing a semiconductor package of the present invention. Fig.Figure 5 is a schematic cross-sectional view showing a step (α4) in the first embodiment of the method for manufacturing a semiconductor package of the present invention. Fig. Figure 6 is a schematic cross-sectional view showing a step (α4) in the first embodiment of the method for manufacturing a semiconductor package of the present invention. Fig. Figure 7 is a schematic cross-sectional view of an example of the forming tool to be used in the second embodiment of the method for manufacturing a semiconductor package of the present invention. Fig. Figure 8 is a schematic cross-sectional view showing a step (β1) in the second embodiment of the method for manufacturing a semiconductor package of the present invention. Fig.Figure 9 is a schematic cross-sectional view showing a step (β2) in the second embodiment of the method for manufacturing a semiconductor package of the present invention. Fig. Figure 10 is a schematic cross-sectional view showing a step (β3) in the second embodiment of the method for manufacturing a semiconductor package of the present invention. Fig. Figure 11 is a schematic cross-sectional view showing a step (β4) in the second embodiment of the method for manufacturing a semiconductor package of the present invention. Fig. Figure 12 is a schematic cross-sectional view showing a step (β5) in the second embodiment of the method for manufacturing a semiconductor package of the present invention. Fig.Figure 13 is a schematic cross-sectional view showing a step (γ1) in the third embodiment of the method for manufacturing a semiconductor package of the present invention. Fig. Figure 14 is a schematic cross-sectional view showing a step (γ3) in the third embodiment of the method for manufacturing a semiconductor package of the present invention. Fig. Figure 15 is a schematic cross-sectional view showing a step (γ4) in the third embodiment of the method for manufacturing a semiconductor package of the present invention. Fig. Figure 16 is a schematic cross-sectional view showing a step (γ5) in the third embodiment of the method for manufacturing a semiconductor package of the present invention. Fig. Figure 17 is a view showing a device for testing adaptability at 180 °C, which has been used in examples. DESCRIPTION OF EXECUTION FORMS

[0017] In this description, the following terms are used with the following meanings.

[0018] A "thermoplastic resin layer" is a layer made from a thermoplastic resin. An additive, such as an inorganic or organic additive, may be added to the thermoplastic resin.

[0019] “Units” in a resin refers to structural units (monomer units) that form the resin.

[0020] A "fluorinated resin" refers to a resin that contains fluorine atoms in its structure.

[0021] The term "(meth)acrylic acid" is a generic term for both acrylic acid and methacrylic acid. The term "(meth)acrylate" is a generic term for both acrylate and methacrylate. The term "(meth)acryloyl" is a generic term for both acryloyl and methacryloyl.

[0022] The thickness of a thermoplastic resin layer is measured according to ISO 4591: 1992 (JIS K7130: B1 method of 1999, method for measuring the thickness of a sample taken from a plastic film or sheet by a mass method).

[0023] The storage elastic modulus E' of a thermoplastic resin layer is measured according to ISO 6721-4: 1994 (JIS K7244-4: 1999). The frequency is 10 Hz, the static force is 0.98 N, and the dynamic displacement is 0.035%. The storage elastic modulus E' measured at a temperature t (°C) is also denoted as E'(t). E' measured at temperatures of 25 °C and 180 °C by increasing the temperature at a rate of 2 °C from 20 °C is denoted as E'(25) at 25 °C and E'(180) at 180 °C, respectively.

[0024] The arithmetic mean roughness (Ra) is the arithmetic mean roughness measured according to JIS B0601: 2013 (ISO4287: 1997, Amd.1: 2009). The standard length Ir (limit λc) for the roughness curve was set to 0.8 mm.

[0025] A mold release film is a film intended for use in a process for manufacturing a semiconductor package by arranging a semiconductor element in a mold and encapsulating the semiconductor element with a curable resin to form a resin encapsulation section. The mold release film is to be arranged on the surface of the mold that is in contact with the curable resin. The mold release film of the present invention is to be arranged, for example, at the time of molding the resin encapsulation section of the semiconductor package, such that it covers the cavity surface of a mold that has a cavity with a shape corresponding to the shape of the resin encapsulation section. When positioned between the molded resin encapsulation section and the mold cavity surface, it facilitates the separation of the resulting semiconductor package from the mold. [Mold release film in the first embodiment]

[0026] The Fig. Figure 1 is a schematic cross-sectional view showing a first embodiment of the mold release film of the present invention.

[0027] The mold tool release film 1 in the first embodiment comprises a first thermoplastic resin layer 2, which is to be in contact with the curable resin at the time of molding the resin encapsulation section, a second thermoplastic resin layer 3, which is to be in contact with the mold tool at the time of molding the resin encapsulation section, and an intermediate layer 4, which is arranged in between.

[0028] At the time of manufacturing a semiconductor package, the mold release film 1 is positioned such that surface 2a on the side of the first thermoplastic resin layer 2 faces the mold cavity and is in contact with the curable resin at the time the resin encapsulation section is formed. Surface 3a on the side of the second thermoplastic resin layer 3 is in close contact with the cavity surface of the mold. As the curable resin cures in this state, the resin encapsulation section is formed with a shape corresponding to the shape of the mold cavity. (First thermoplastic resin layer)

[0029] The first thermoplastic resin layer 2 has a storage elasticity modulus E' (180) at 180 °C of 10 to 300 MPa, particularly preferably of 30 to 150 MPa. 180 °C is the mold temperature for a typical molding process.

[0030] If E' (180) is at most the upper limit in the aforementioned range, the mold release film exhibits excellent mold conformability. At the time of encapsulation of the semiconductor element, the mold release film is reliably in close contact with the cavity surface, and the shape of the mold, including its corners, is accurately transferred to the resin encapsulation section. As a result, a very accurate resin encapsulation section is formed, and the yield of the encapsulated semiconductor package will be high.

[0031] If the aforementioned E' (180) exceeds the upper limit in the aforementioned range, the mold release film's molding ability tends to be insufficient at the time of adaptation to the mold under vacuum. Therefore, during injection molding, at the time of clamping, the semiconductor element may be damaged by contact with the film, which has not fully adapted, or the corner sections of the encapsulated section may be missing. During compression molding, due to the insufficient molding ability of the mold release film, the curable resin may overflow from the mold when the curable resin is applied to the film, or the corner sections of the encapsulated section may be missing.

[0032] If E' (180) is at least the lower limit in the aforementioned range, the mold release film is less likely to become wavy. Furthermore, when the mold release film is positioned to cover the mold cavity, and is stretched while the mold release film is being pulled, because the mold release film is not too soft, the stress is applied uniformly to the mold release film, making wrinkling less likely. As a result, there will be no transfer of wrinkling from the mold release film to the surface of the resin encapsulation section, and the surface of the resin encapsulation section will have an excellent appearance.

[0033] The storage elasticity modulus E' of the first thermoplastic resin layer 2 can be adjusted by the crystallinity of the thermoplastic resin forming the first thermoplastic resin layer 2. Specifically, E' is lower the lower the crystallinity of the thermoplastic resin. The crystallinity of the thermoplastic resin can be adjusted by a known method. For example, in the case of an ethylene / tetrafluoroethylene copolymer, the crystallinity can be adjusted by the ratio of units based on tetrafluoroethylene and ethylene, or by the type and content of units based on another monomer different from tetrafluoroethylene and ethylene.

[0034] The thickness of the first thermoplastic resin layer 2 is from 12 to 50 µm, preferably from 25 to 40 µm.

[0035] If the thickness of the first thermoplastic resin layer 2 is at least the lower limit in the aforementioned range, the mold release film 1 is less likely to become wavy. Furthermore, handling the mold release film 1 is simple, and wrinkling is less likely when positioning the mold release film 1 so that it covers the mold cavity while being drawn.

[0036] If the thickness of the first thermoplastic resin layer 2 is at most the upper limit in the aforementioned range, the mold release film 1 is easily deformable and exhibits excellent mold conformability.

[0037] The first thermoplastic resin layer 2 preferably has a mold release property by which the cured curable resin (resin encapsulation section) can be easily detached from the mold release film 1 in a state where it is in contact with the side of the thermoplastic resin layer 2 of the mold release film 1. Furthermore, it preferably has heat resistance such that it is resistant to the mold temperature, typically 150 to 180 °C, during molding.

[0038] The thermoplastic resin (hereinafter also referred to as the thermoplastic resin I), which forms the first thermoplastic resin layer 2, comprises, with regard to the aforementioned mold release property and heat resistance as well as strength for resistance to flow and pressure of the curable resin, elongation at high temperature, etc., one or more thermoplastic polymers, and all thermoplastic polymers included in the first thermoplastic resin layer are fluoroolefin polymers.

[0039] A fluoroolefin polymer is a polymer that contains units based on a fluoroolefin. Examples of fluoroolefins include tetrafluoroethylene, vinyl fluoride, vinylidene fluoride, trifluoroethylene, hexafluoropropylene, and chlorotrifluoroethylene. A single fluoroolefin can be used alone, or two or more types can be combined.

[0040] The fluoroolefin polymer can be, for example, an ethylene / tetrafluoroethylene copolymer (hereinafter also referred to as ETFE), polytetrafluoroethylene, a perfluoro(alkyl vinyl ether) / tetrafluoroethylene copolymer, etc. A single type of fluoroolefin polymer can be used alone, or two or more types can be used in combination.

[0041] This document also describes polystyrene in general terms. With regard to heat resistance and adaptability to molding tools, syndiotactic polystyrene is preferred. The polystyrene can generally be a stretched polystyrene, and one type could be used alone, or two or more types could be used in combination. However, according to the claimed invention, all thermoplastic polymers included in the first thermoplastic resin layer are fluoroolefin polymers.

[0042] This document also describes polyolefins in general. Polymethylpentene, with a melting point of at least 200 °C, is preferred with regard to its mold release properties and mold conformability. One type of polyolefin could be used alone, or two or more types could be used in combination. However, according to the claimed invention, all thermoplastic polymers included in the first thermoplastic resin layer are fluoroolefin polymers.

[0043] The thermoplastic resin I is selected from fluoroolefin polymers. Of these, ETFE is particularly preferred due to its high elongation at high temperatures. A single ETFE type can be used, or two or more types can be used in combination.

[0044] ETFE is a copolymer comprising units based on tetrafluoroethylene (hereinafter also referred to as TFE) and units based on ethylene (hereinafter also referred to as E).

[0045] A preferred ETFE is one comprising units based on TFE, units based on E, and units based on a third monomer different from TFE and E. The crystallinity of the ETFE, i.e., the storage elastic modulus of the first thermoplastic resin layer 2, can be easily adjusted by the type and content of units based on the third monomer. Furthermore, the presence of units based on the third monomer (especially a monomer containing fluorine atoms) improves the tensile strength and elongation at high temperatures (especially at approximately 180 °C).

[0046] The third monomer can be a monomer that contains fluorine atoms or a monomer that does not contain a fluorine atom.

[0047] The following monomers (a1) to (a5) can be named as monomers that contain fluorine atoms. Monomer (a1): A fluoroolefin with at most 3 carbon atoms. Monomer (a2): A perfluoroalkylethylene monomer that is linked by X(CF2) n CY=CH2 is represented (where X and Y are each independently a hydrogen atom or a fluorine atom and n is an integer from 2 to 8). Monomer (a3): A fluorovinyl ether. Monomer (a4): A functional group-containing fluorovinyl ether. Monomer (a5): A fluorinated monomer that has an aliphatic ring structure.

[0048] The monomer (a1) can be, for example, a fluoroethylene (such as trifluoroethylene, vinylidene fluoride, vinyl fluoride or chlorotrifluoroethylene) or a fluoropropylene (such as hexafluoropropylene (hereinafter also referred to as HFP) or 2-hydropentafluoropropylene).

[0049] The monomer (a2) is preferably a monomer in which n is from 2 to 6, and particularly preferably a monomer in which n is from 2 to 4. Furthermore, a monomer in which X is a fluorine atom and Y is a hydrogen atom, i.e., a (perfluoroalkyl)ethylene, is particularly preferred.

[0050] The following compounds can be mentioned as specific examples of the monomer (a2). CF3CF2CH=CH2, CF3CF2CF2CF2CH=CH2 ((Perfluorobutyl)ethylene, hereinafter also referred to as PFBE), CF3CF2CF2CF2CF=CH2, CF2HCF2CF2CF=CH2, CF2HCF2CF2CF2CF =CH2: etc.

[0051] The following compounds can be given as specific examples of the monomer (a3). One of the following, which is a diene, is a cyclopolymerizable monomer. CF2=CFOCF3 CF2=CFOCF2CF3, CF2=CF(CF2)2CF3 (Perfluoro(propyl vinyl ether), hereinafter also referred to as PPVE), CF2=CFOCF2CF(CF3)O(CF2)2CF3, CF2=CFO(CF2)3O(CF2)2CF3, CF2=CFO(CF2CF(CF3)O)2(CF2)2CF3, CF2=CFOCF2CF(CF3)O(CF2)2CF3, CF2=CFOCF2CF=CF2, CF2=CFO(CF2)2CF=CF2, etc.

[0052] The following compounds can be mentioned as specific examples of the monomer (a4). CF2=CFO(CF2)3CO2CH3, CF2=CFOCF2CF(CF3)O(CF2)3CO2CH3, CF2=CFOCF2CF(CF3)O(CF2)2SO2F, etc.

[0053] Specific examples of the monomer (a5) include perfluoro(2,2-dimethyl-1,3-dioxol), 2,2,4-trifluoro-5-trifluoromethoxy-1,3-dioxol, perfluoro(2-methylene-4-methyl-1,3-dioxolane), etc.

[0054] The following monomers (b1) to (b4) can be named as monomers that do not contain a fluorine atom. Monomer (b1): An olefin. Monomer (b2): A vinyl ester. Monomer (b3): ​​A vinyl ether. Monomer (b4): An unsaturated acid anhydride.

[0055] Specific examples of the monomer (b1) include propylene, isobutene, etc.

[0056] Specific examples of the monomer (b2) include vinyl acetate, etc.

[0057] Specific examples of the monomer (b3) include ethyl vinyl ether, butyl vinyl ether, cyclohexyl vinyl ether, hydroxybutyl vinyl ether, etc.

[0058] Specific examples of the monomer (b4) include maleic anhydride, itaconic anhydride, citraconic anhydride, 5-norbornene-2,3-dicarboxylic anhydride (“himic anhydride”), etc.

[0059] The third monomer can be a single type, or two or more types can be used in combination.

[0060] The third monomer is preferably monomer (a2), HFP, PPVE or vinyl acetate, more preferably HFP, PPVE, CF3CF2CH=CH2 or PFBE, particularly preferably PFBE, because this makes it easy to adjust the crystallinity, i.e., the storage elastic modulus, and because units are based on a third monomer (in particular a monomer having fluorine atoms), the tensile strength and elongation at a high temperature (in particular at about 180 °C) will be excellent.

[0061] That is, as ETFE, a copolymer is particularly preferred which has units based on TFE, units based on E and units based on PFBE.

[0062] In ETFE, the molar ratio (TFE / E) of TFE-based units to E-based units is preferably from 80 / 20 to 40 / 60, more preferably from 70 / 30 to 45 / 55, and particularly preferably from 65 / 35 to 50 / 50. If the TFE / E ratio is within the aforementioned range, the heat resistance and mechanical properties of ETFE will be excellent.

[0063] The proportion of units based on the third monomer in ETFE is preferably from 0.01 to 20 mol%, more preferably from 0.10 to 15 mol%, and particularly preferably from 0.20 to 10 mol%, based on the total (100 mol%) of all units forming ETFE. If the proportion of units based on the third monomer is within the aforementioned range, the heat resistance and mechanical properties of ETFE will be excellent.

[0064] In a case where the units based on the third monomer contain PFBE-based units, the proportion of PFBE-based 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%, based on the total (100 mol%) of all units forming ETFE. If the proportion of PFBE-based units is within the aforementioned range, the tensile modulus of the mold release film at 180 °C can be within the aforementioned range. Furthermore, the tensile strength and elongation at high temperature (especially at about 180 °C) will be improved.

[0065] The flowability (MFR) of ETFE is preferably from 2 to 40 g / 10 min, more preferably from 5 to 30 g / 10 min, and particularly preferably from 10 to 20 g / 10 min. If the MFR is within the aforementioned range, the formability of ETFE will be improved and the mechanical properties of the mold release film will be excellent.

[0066] The MFR of ETFE is a value measured at a load of 49 N at 297 °C according to ASTM D3159.

[0067] The first thermoplastic resin layer 2 can consist solely of thermoplastic resin I, or it can contain an additive, such as an inorganic or organic additive. The inorganic additive could be, for example, carbon black, silicon dioxide, titanium dioxide, cerium oxide, aluminum cobalt oxide, mica, zinc oxide, etc. The organic additive could be, for example, silicone oil, a metal soap, etc.

[0068] With a view to reducing the storage elasticity modulus of the first thermoplastic resin layer 2 to improve the mold adaptability, the first thermoplastic resin layer 2 preferably does not contain an inorganic additive.

[0069] The first thermoplastic resin layer 2 can have a single-layer or a multi-layer structure. With regard to mold conformability, tensile elongation, manufacturing costs, etc., a single-layer structure is preferred.

[0070] With regard to excellent mold release properties, the first thermoplastic resin layer 2 has a single-layer structure made of a fluoropolymer or a multi-layer structure made of a fluoropolymer (hereinafter also referred to as a fluoropolymer layer), particularly preferably a single-layer structure made of a fluoropolymer.

[0071] The multilayer structure is a structure that comprises multiple layers of fluorinated resin.

[0072] If the first thermoplastic resin layer 2 is made of a fluorinated resin, the mold release film 1 exhibits excellent mold release properties, sufficient heat resistance to withstand mold temperatures (typically 150 to 180 °C) during molding, sufficient strength to resist the flow or pressure of the curing resin, etc., and also excellent elongation at high temperatures. In particular, if the first thermoplastic resin layer 2 has a single-layer structure, compared to a multi-layer structure, the physical properties, such as mold conformability, tensile elongation, etc., will be excellent, its suitability as a mold release film will be improved, and there is also a tendency for lower manufacturing costs.

[0073] In the first thermoplastic resin layer 2, the surface that is in contact with the curable resin at the time of forming the resin encapsulation section, i.e., the surface 2a on the side of the first thermoplastic resin layer 2 of the mold release film 1, can be smooth or it can have irregularities. With regard to mold release properties, it is preferred that irregularities are present.

[0074] The arithmetic mean roughness (Ra) of the surface 2a in the case of a smooth surface is preferably from 0.01 to 0.2 µm, particularly preferably from 0.05 to 0.1 µm.

[0075] The Ra of the surface 2a in the case where irregularities are formed is preferably from 1.0 to 2.1 µm, particularly preferably from 1.2 to 1.9 µm.

[0076] The surface shape, in cases where irregularities are present, can be a shape in which a plurality of convexities and / or concavities are randomly distributed, or it can be a shape in which a plurality of convexities and / or concavities are regularly arranged. Furthermore, the shapes and sizes of the plurality of convexities and / or concavities can be the same or different.

[0077] Convexities can be, for example, elongated ribs extending across the surface of the mold release film, or protrusions distributed across it. Concavities can be, for example, elongated grooves extending across the surface of the mold release film, or holes distributed across it.

[0078] The shape of ribs or grooves can be straight, curved, or bent. Multiple ribs or grooves can be present on the surface of the mold release film, either parallel or in strips. The cross-sectional shape of the ribs or grooves in a direction perpendicular to the longitudinal direction can be polygonal, such as triangular (V-shaped), semicircular, or similar.

[0079] The shape of the protrusions or holes can be polygonal, such as triangular-pyramidal, square-pyramidal or hexagonal-pyramidal, conical, hemispherical, polyhedral, or other various irregular shapes, etc. (Second thermoplastic resin layer)

[0080] The storage elasticity modulus E' (180) at 180 °C and the thickness of the second thermoplastic resin layer 3 and preferred regions thereof are identical to those of the first thermoplastic resin layer 2.

[0081] E' (180) and the thickness of the second thermoplastic resin layer 3 can each be identical to or different from E' (180) and the thickness of the first thermoplastic resin layer 2.

[0082] The difference between E'(25) at 25 °C of the first thermoplastic resin layer and E'(25) at 25 °C of the second thermoplastic resin layer (i.e., |E'(25) of the first thermoplastic resin layer - E'(25) of the second thermoplastic resin layer) is, however, at most 1200 MPa, and particularly preferably at most 1000 MPa. If the difference of E'(25) is at most the lower limit in the aforementioned range, waviness can be suppressed. With regard to the suppression of waviness, the difference in thickness of the first thermoplastic resin layer 2 is preferably at most 20 µm.

[0083] The thermoplastic resin (hereinafter also referred to as thermoplastic resin II) forming the second thermoplastic resin layer 3 is selected with regard to the separability of the mold release film 1 from the mold, its heat resistance so that it is resistant to the mold temperature (typically 150 to 180 °C) at the time of molding, its strength for resistance to flow or pressure of the curing resin, its elongation at high temperature, etc., preferably at least one member is selected from the group consisting of a fluoropolymer, a polystyrene, a polyester, a polyamide, an ethylene / vinyl alcohol copolymer, and a polyolefin, all with a melting point of at least 200 °C. One of these thermoplastic resins may be used alone, or two or more of them may be used in combination.

[0084] The fluorinated resin, the polystyrene and the polyolefin having a melting point of at least 200 °C may be identical to those mentioned above in general terms with regard to the thermoplastic resin I.

[0085] With regard to heat resistance and strength, polyethylene terephthalate (hereinafter also referred to as PET), highly malleable PET, polybutylene terephthalate (hereinafter also referred to as PBT) or polynaphthalene interephthalate are preferred as polyesters.

[0086] The highly malleable PET is a PET whose malleability is improved by copolymerizing an additional monomer alongside ethylene glycol and terephthalic acid (or dimethyl terephthalate). Specifically, it is a PET whose glass transition temperature (Tg), measured using the following method, is at most 105 °C.

[0087] Tg is the temperature at which tan δ (E'' / E'), which is the ratio of the loss elasticity modulus E'' to the storage elasticity modulus E', measured according to IS06721-4: 1994 (JIS K7244-4: 1999), reaches its maximum value. Tg is measured by increasing the temperature from 20 °C to 180 °C at a rate of 2 °C / min at a frequency of 10 Hz, with a static force of 0.98 N and a dynamic displacement of 0.035%.

[0088] As a polyester, one type can be used alone, or two or more types can be used in a combination.

[0089] Nylon 6 or Nylon MXD6 is preferred as the polyamide due to its heat resistance, strength, and gas barrier properties. The polyamide can be either a stretched or unstretched polyamide. A single polyamide type can be used, or two or more types can be used in combination.

[0090] As thermoplastic resin II, at least one member selected from the group consisting of polymethylpentene, a fluoroolefin polymer, highly moldable PET and PBT is preferred, and at least one member selected from the group consisting of ETFE, highly moldable PET and PBT is particularly preferred.

[0091] The second thermoplastic resin layer 3 can be a resin layer consisting solely of thermoplastic resin II, or a resin layer to which an additive has been added, such as an inorganic or organic additive. The inorganic and organic additives can each be identical to those described above.

[0092] With a view to preventing contamination of the molding tool or improving the molding tool adaptability by lowering the storage elasticity modulus of the second thermoplastic resin layer 3, the second thermoplastic resin layer 3 preferably does not contain an inorganic additive.

[0093] The second thermoplastic resin layer 3 can have a single-layer or a multi-layer structure. With regard to mold conformability, tensile elongation, manufacturing costs, etc., it preferably has a single-layer structure.

[0094] In the case of the second thermoplastic resin layer 3, the surface that is in contact with the molding tool at the time of forming the resin encapsulation section, i.e., the surface 3a on the side of the second thermoplastic resin layer 3 of the molding tool release film 1, may be smooth or it may have formed irregularities.

[0095] The arithmetic mean roughness (Ra) of surface 3a, in the case where it is smooth, is preferably from 0.01 to 0.2 µm, more preferably from 0.05 to 0.1 µm. The Ra of surface 3a, in the case where irregularities are present, is preferably from 1.5 to 2.1 µm, more preferably from 1.6 to 1.9 µm.

[0096] The surface shape, in cases where irregularities are present, can be a shape in which a plurality of convexities and / or concavities are randomly distributed, or it can be a shape in which a plurality of convexities and / or concavities are regularly arranged. The shapes and sizes of the plurality of convexities and / or concavities can be the same or different. Specific examples of the convexities, concavities, ribs, protrusions, or holes are identical to those described above.

[0097] In a case where irregularities are formed on both surface 2a and surface 3a, Ra and the surface shape of each surface can be the same or different. (Intermediate layer)

[0098] The intermediate layer 4 comprises a layer containing a polymeric antistatic agent (hereinafter also referred to as a polymeric antistatic layer). Because it contains a polymeric antistatic agent, the polymeric antistatic layer exhibits low surface resistance and contributes to the antistatic performance of the mold release film 1. The intermediate layer may further comprise other layers different from the polymeric antistatic layer.

[0099] With regard to antistatic performance, the surface resistance of the intermediate layer 4 is preferably at most 10 10 Ω / □, particularly preferably at most 10 9Ω / □. If the surface resistance is at most 10 10 Since the antistatic performance is provided at surface 2a on the side of the first thermoplastic resin layer 2 of the mold release film 1, even if part of the semiconductor element is in direct contact with the mold release film 1 during the manufacture of a semiconductor package, destruction of the semiconductor element due to charging and discharging of the mold release film can be sufficiently prevented.

[0100] The surface resistance of intermediate layer 4 should ideally be as low as possible with regard to antistatic performance, and there is no specific lower limit. The surface resistance value of intermediate layer 4 tends to be low when the conductivity of the polymeric antistatic agent is high or when the concentration of the polymeric antistatic agent increases. <Polymere antistatische Schicht>

[0101] A polymeric antistatic agent can be any polymer compound commonly known as an antistatic agent. Examples include a cationic copolymer containing a quaternary ammonium base in its side groups, an anionic compound containing polystyrenesulfonic acid, a compound with a polyalkylene oxide chain (a polyethylene oxide chain or a polypropylene oxide chain is preferred), a polyethylene glycol methacrylate copolymer, a polyether ester amide, a polyether amide imide, a polyether ester, a nonionic polymer such as an ethylene oxide-epichlorohydrin copolymer, a π-conjugated conductive polymer, and so on. Any one of these can be used alone, or two or more can be used in combination.

[0102] The quaternary ammonium salt in the copolymer, which has a quaternary ammonium base in its side groups, has the effect of imparting rapid dielectric polarization relaxation due to dielectric polarization and conductivity.

[0103] The aforementioned copolymer preferably has a carboxyl group in its side groups together with a quaternary ammonium base. If it has a carboxyl group, the copolymer exhibits crosslinkability and can even form the intermediate layer 4 on its own. Furthermore, when used in combination with an adhesive, such as a urethane adhesive, it reacts with the adhesive to form a crosslinked structure, thereby considerably improving adhesion, durability, and other mechanical properties.

[0104] The copolymer may also contain a hydroxyl group in its side groups. This hydroxyl group improves adhesion by reacting with a functional group, such as an isocyanate group, in the adhesive.

[0105] The aforementioned copolymer can be obtained by copolymerizing a monomer possessing the respective functional group mentioned above. Specific examples of the monomer possessing a quaternary ammonium base include a quaternized dimethylaminoethyl acrylate product (containing an anion such as chloride, sulfate, sulfonate, alkylsulfonate, etc., as a counterion), etc. Specific examples of the monomer possessing a carboxyl group include (meth)acrylic acid, (meth)acryloyloxyethyl succinic acid, phthalic acid, hexyhydrophthalic acid, etc.

[0106] Other monomers, different from these, can be copolymerized. Such other monomers can be, for example, vinyl derivatives such as alkyl(meth)acrylates, styrene, vinyl acetate, vinyl halides, olefins, etc.

[0107] The proportion of units possessing the respective functional group in the copolymer can be adjusted appropriately. The proportion of units possessing a quaternary ammonium base is preferably from 15 to 40 mol% based on the total amount of all units. If this proportion is at least 15 mol%, the antistatic effect will be excellent. If the proportion exceeds 40 mol%, the hydrophilicity of the copolymer may become too high. The proportion of units possessing a carboxyl group is preferably from 3 to 13 mol% based on the total amount of all units.

[0108] If the copolymer has a carboxyl group in its side groups, a crosslinking agent (curing agent) can be added to the copolymer. The crosslinking agent can be, for example, a bifunctional epoxy compound such as glycerol diglycidyl ether, a trifunctional epoxy compound such as trimethylolpropane triglycidyl ether, or a polyfunctional compound such as an ethyleneimine compound such as trimethylolpropane triazinyl ether.

[0109] An imidazole derivative, such as 2-methylimidazole or 2-ethyl- or 4-methylimidazole, or other amines can be added to the copolymer as a ring-opening reaction catalyst of the bifunctional or trifunctional epoxy compound.

[0110] A π-conjugated conductive polymer is a conductive polymer that has a main chain with a developed π-conjugation. Any known π-conjugated conductive polymer can be used as a π-conjugated conductive polymer; examples include polythiophene, polypyrrole, polyaniline, and derivatives thereof.

[0111] The polymeric antistatic agent can be either a product manufactured using a known process or a commercially available product. For example, a commercially available copolymer containing a quaternary ammonium base and a carboxyl group in the side groups is "Bondeip (BONDEIP, trade name)-PA 100 main agent", manufactured by Konishi Co.

[0112] The polymeric antistatic layer can be, for example, the following layers (1) to (4).

[0113] Layer (1): The polymeric antistatic layer is a layer that has a film-forming ability and the layer is formed by wet coating with the polymeric antistatic agent as such or dissolved in a solvent and then, if necessary, drying.

[0114] Layer (2): The polymeric antistatic layer is a layer that has a film-forming ability and is meltable, and the layer is formed by melt coating with the polymeric antistatic agent.

[0115] Layer (3): The binder is a film-forming agent that is meltable and the layer is formed by melt coating with a composition formed by dispersing or dissolving a polymeric antistatic agent in the binder.

[0116] Layer (4): The binder is a film-forming agent, and the layer is formed by wet coating a composition comprising the binder and a polymeric antistatic agent, either as such or dissolved in a solvent, and optionally by drying. A layer that falls below layer (1) should not be included in layer (4).

[0117] In layer (1), the polymeric antistatic agent having film-forming properties means that the polymeric antistatic agent is soluble in a solvent, such as an organic solvent, and that when the solution is wet-coated and subsequently dried, a film is formed.

[0118] In layer (2), "meltable" means that the polymeric antistatic agent can be melted by heating. In layers (3) and (4), "has film-forming properties" and "meltable" have the same meaning with regard to the binder.

[0119] The polymeric antistatic agent in layer (1) can be a crosslinking agent or a non-crosslinking agent. If the polymeric antistatic agent is crosslinking, a crosslinking agent can be used in combination with it.

[0120] The polymeric antistatic agent, which exhibits film-forming ability and crosslinkability, can, for example, be a copolymer that has a quaternary ammonium base and a carboxyl group in the side groups.

[0121] The crosslinking agent can be identical to the one described above.

[0122] The thickness of layer (1) is preferably from 0.01 to 1.0 µm, particularly preferably from 0.03 to 0.5 µm. If the thickness of layer (1) is less than 0.01 µm, a sufficient antistatic effect cannot be obtained, whereas if it exceeds 1.0 µm, the adhesion between the first thermoplastic resin layer 2 and the second thermoplastic resin layer 3 may deteriorate when an adhesive layer is applied to it.

[0123] The polymeric antistatic agent in layer (2) can be, for example, a polyolefin resin containing a surfactant, carbon black, etc. Commercially available products include, for example, Perekutoron HS (from Sanyo Chemical Industries, Ltd.), etc. The preferred thickness range for layer (2) is identical to the preferred thickness range for layer (1).

[0124] A general-purpose thermoplastic resin can be used as the binder in layer (3). For adhesion during melt forming, the thermoplastic resin is preferably a resin with a functional group that contributes to adhesion. For example, a carbonyl group can be used as such a functional group. The content of the polymeric antistatic agent in layer (3) is preferably from 10 to 40 parts by mass, and particularly preferably from 10 to 30 parts by mass, based on the total mass of layer (3). The preferred thickness range of layer (3) is identical to the preferred thickness range of layer (1).

[0125] An example of a composition forming layer (4) is an adhesive. The adhesive should be an adhesive comprising a main agent and a curing agent, and should be cured by heating, etc., so that it exhibits adhesion.

[0126] The adhesive can be a one-component adhesive or it can be a two-component adhesive.

[0127] The adhesive for forming layer (4) (hereinafter also referred to as the layer-forming adhesive (4)) may, for example, be an adhesive in which a polymeric antistatic agent is added to an adhesive that does not include a polymeric antistatic agent.

[0128] The polymeric antistatic adhesive to be added to the adhesive can be an agent that has film-forming properties or an agent that does not have film-forming properties (e.g., a π-conjugated conductive polymer).

[0129] As an adhesive that does not contain a polymeric antistatic agent, a substance known as a dry lamination adhesive can be used. For example, a polyvinyl acetate type adhesive, a polyacrylate type adhesive consisting of a homopolymer or copolymer of an acrylic acid ester (ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate ester, etc.) or a copolymer of an acrylic acid ester and other monomers (methyl methacrylate, acrylonitrile, styrene, etc.), a cyanoacrylate type adhesive, or an ethylene type adhesive consisting of, for example, a copolymer of ethylene with another monomer (such as vinyl acetate, ethyl acrylate, acrylic acid, methacrylic acid, etc.).) is manufactured, a cellulose-type adhesive, a polyester-type adhesive, a polyamide-type adhesive, a polyimide-type adhesive, an amino resin-type adhesive consisting of a urea resin or a melamine resin, a phenol resin-type adhesive, an epoxy-type adhesive, a polyurethane-type adhesive obtained by crosslinking a polyol (a polyether polyol, a polyester polyol, etc.) with an isocyanate and / or isocyanurate, a rubber-type adhesive consisting of chloroprene rubber, nitrile rubber, styrene-butadiene rubber, etc., a silicone adhesive, an inorganic adhesive made from an alkali metal silicate, low-melting-point glass, etc., or other adhesives are used.

[0130] In the adhesive for forming the layer (4), the content of the polymeric antistatic agent is preferably an amount such that the surface resistance of the layer (4) is preferably at most 10 10 Ω / □, particularly preferably at most 10 9 Ω / □ is.

[0131] With regard to antistatic performance, the content of the polymeric antistatic agent in the adhesive forming layer (4) is preferably as high as possible; however, in a case where the polymeric antistatic agent is a π-conjugated conductive polymer and an intermediate layer 4 is to be formed using an agent as the adhesive forming layer (4) which has a π-conjugated conductive polymer added to an adhesive which does not contain a polymeric antistatic agent, if the content of the polymeric antistatic agent becomes large, the adhesion of layer (4) tends to decrease and the adhesion between the first thermoplastic resin layer 2 and the second thermoplastic resin layer 3 may become insufficient.Therefore, in such a case, the content of the polymeric antistatic agent in the adhesive forming layer (4) is preferably at most 40% by mass, and more preferably at most 30% by mass, based on the solids content of the resin as a binder. The lower limit is preferably 1% by mass, and more preferably 5% by mass.

[0132] The thickness of layer (4) is preferably from 0.2 to 5 µm, more preferably from 0.5 to 2 µm. If the thickness of layer (4) is at least the lower limit in the aforementioned range, the adhesion between the first thermoplastic resin layer and the second thermoplastic resin layer will be excellent. If the thickness is at most the upper limit in the aforementioned range, the productivity will be excellent.

[0133] The polymeric antistatic layer comprising the intermediate layer (4) can be one layer, two layers, or more layers. For example, it can have only one of the layers (1) to (4), or it can have two or more of them.

[0134] For ease of fabrication, layer (1) is preferred as the polymeric antistatic layer. Layer (1) can be used in combination with at least one of layers (2) to (4). <Weitere Schichten>

[0135] Other layers, different from the polymeric antistatic layer, may include, for example, a thermoplastic resin layer, a layer consisting of an adhesive that does not contain a polymeric antistatic agent (hereinafter also referred to as a non-antistatic adhesive layer), a gas barrier layer, etc. The thermoplastic resin layer may be identical to the first thermoplastic resin layer 2 or the second thermoplastic resin layer 3. The adhesive in the non-antistatic adhesive layer may be identical to that mentioned above. The gas barrier layer may, for example, be a metal layer, a vapor-deposited metal layer, a vapor-deposited metal oxide layer, etc. <Schichtstruktur der Zwischenschicht>

[0136] The intermediate layer 4 is preferably a layer comprising a polymeric antistatic layer and a non-antistatic adhesive layer, or a layer comprising layer (4). If the intermediate layer 4 has such a structure, the mold release film 1 can be produced by a dry lamination process.

[0137] The following (11) to (15) can be named as preferred layer structures for the intermediate layer 4. (11) A layer in which each of the layers (1) to (3) and a non-antistatic adhesive layer are successively laminated from the side of the first thermoplastic resin layer 2. (12) A layer in which layer (4) and a non-antistatic adhesive layer are successively laminated from the side of the first thermoplastic resin layer 2. (13) A layer consisting only of one layer of layer (4). (14) A layer in which layer (4), a third thermoplastic resin layer and a non-antistatic adhesive layer are successively laminated from the side of the first thermoplastic resin layer 2. (15) A layer in which layer (4), a third thermoplastic resin layer, a gas barrier layer and a non-antistatic adhesive layer are successively laminated from the side of the first thermoplastic resin layer 2.

[0138] Of the foregoing, (11) or (13) is preferred, (11) is more preferred and a layer in which one of the layers (1) to (3) is layer (1) is particularly preferred.

[0139] The thermoplastic resin forming the third thermoplastic resin layer can be identical to the thermoplastic resin II described above. The thickness of the third thermoplastic resin layer is not specifically limited, but thicknesses of 6 to 50 µm are preferred.

[0140] The thickness of the intermediate layer 4 is preferably from 0.1 to 55 µm, particularly preferably from 0.5 to 25 µm. If the thickness of the intermediate layer 4 is at least the lower limit in the aforementioned range, the antistatic performance and adhesion are sufficiently excellent, and if the thickness is at most the upper limit, the mold conformability will be excellent. <Dicke des Formwerkzeugtrennfilms>

[0141] The thickness of the mold release film 1 is preferably from 25 to 100 µm, and particularly preferably from 40 to 75 µm. If the thickness is at least the lower limit in the aforementioned range, the mold release film is less likely to become wavy. Furthermore, handling the mold release film is simple, and if the mold release film is positioned to cover the mold cavity while being drawn, wrinkling is less likely. If the thickness is at most the upper limit in the aforementioned range, the mold release film 1 can be easily deformed, thus improving its conformability to the shape of the mold cavity. This allows the mold release film to lie close to the cavity surface and consistently form a high-quality resin encapsulation section.If the mold cavity is larger, the thickness of the mold release film 1 within the aforementioned area is preferably thinner. Furthermore, the mold release film within the aforementioned area is preferably thinner if the mold is more complex and has a plurality of cavities. (Waviness of the mold release film)

[0142] The waviness of the mold tool release film 1, as measured by the following measuring method, is preferably at most 1 cm, particularly preferably at most 0.5. (Method for measuring waviness)

[0143] At 20 to 25 °C, a square-shaped mold release film of 10 cm × 10 cm is left on a flat metal plate for 30 seconds, the maximum height (cm) of the section of the mold release film lifted from the metal plate is measured and the measurement is used as the waviness.

[0144] If the mold release film is wavy, it will not adsorb well to the mold. To feed the mold release film to the mold during semiconductor package manufacturing, it is common to use a roll-to-roll system (a system in which a long mold release film is unwound from a reel and fed to the mold by being pulled through the reel and then a take-up reel). However, a pre-cutting system (a system in which a short mold release film, pre-cut to fit the mold, is fed to the mold) has also recently come into use.If waviness occurs in the mold release film, especially in the case of the pre-cutting system, there will be a problem in that the mold release film is not properly adsorbed onto the mold.

[0145] If the waviness is at most 1 cm, even in the case of the pre-cutting system, the adsorption of the mold release film onto the mold can be satisfactorily carried out.

[0146] The degree of waviness can be adjusted by the storage elasticity modulus and the thickness of the first thermoplastic resin layer 2 and the second thermoplastic resin layer 3, the dry lamination conditions, etc. (Method for producing a mold release film 1)

[0147] The mold release film 1 is preferably produced by a manufacturing process comprising a step of dry lamination of a first film to form a first thermoplastic resin layer 2 and a second film to form a second thermoplastic resin layer 3 using an adhesive.

[0148] Dry lamination can be carried out using a known method.

[0149] For example, the adhesive is laminated to one side of the first film and the second film, the adhesive is applied and dried, and the other film is placed on top. The two films are then bonded by passing them between a pair of rollers (laminating rollers) heated to a predetermined temperature (drying lamination temperature). Consequently, a laminate can be obtained in which a first thermoplastic resin layer 2, an intermediate layer 4 containing an adhesive layer, and a second thermoplastic resin layer 3 are laminated in that order.

[0150] The adhesive may or may not contain a polymeric antistatic agent.

[0151] In a case where an adhesive that does not contain a polymeric antistatic agent is to be used (in a case where the adhesive layer is a non-antistatic adhesive layer), a step of forming a polymeric antistatic layer on the surface (the side of the intermediate layer 4) of one or both of the first film and the second film is carried out before the dry lamination step.

[0152] For example, a polymeric antistatic agent with film-forming properties is applied and dried to one side of both the first and second films. Then, an adhesive agent without a polymeric antistatic agent is applied and dried. Finally, the other film is laid over this and bonded by passing it between a pair of rollers (laminating rollers) heated to a predetermined temperature (drying lamination temperature). Consequently, a laminate can be obtained in which a first thermoplastic resin layer 2, a layer (1), a non-antistatic adhesive layer as an intermediate layer 4, and a second thermoplastic resin layer 3 are laminated in this order.

[0153] Before the dry lamination step and before or after the formation of the polymeric antistatic layer, a step of forming further layers, different from the non-antistatic adhesive layer and the polymeric antistatic layer, can be carried out.

[0154] In a case where the adhesive containing the polymeric antistatic agent is to be used (in a case where the adhesive layer is layer (4)), a step of forming a polymeric antistatic layer or a step of forming further layers may or may not be carried out.

[0155] After dry lamination, curing, cutting, etc. can be carried out if necessary.

[0156] In the step of carrying out dry lamination, the storage elasticity modulus E1' (MPa), the thickness T1 (µm), the width W1 (mm) and the tensile force F1 (N) exerted on it at the dry lamination temperature t (°C) of one of the first and the second film and the storage elasticity modulus E2' (MPa), the thickness T2 (µm), the width W2 (mm) and the tensile force F2 (N) exerted on it at the dry lamination temperature t (°C) of the other film preferably satisfy the following formula (I) and particularly preferably satisfy the following formula (II): 0.8≤{(E1'×T1×W1)×F2} / {(E2'×T2×W2)×F1}≤1.2 0.9≤{(E1'×T1×W1)×F2} / {(E2'×T2×W2)×F1}≤1.1 where the storage elasticity modulus E1' (180) and E2' (180) at 180 °C is from 10 to 300 MPa, the difference in the storage elasticity modulus at 25°C, i.e. |E1' (25) - E2' (25)|, is at most 1200 MPa, and T1 and T2 are each from 12 to 50 (µm).

[0157] By performing the dry lamination step so that it satisfies formula (I), the difference in stress remaining in the two films during dry lamination is minimized, thereby making the mold release film to be obtained a film that is less likely to become wavy.

[0158] For dry lamination, a commercially available film can be used, or a film manufactured using a known process can be used. The film can be one that has undergone surface treatment, such as corona treatment, plasma treatment, adhesion promoter treatment, etc.

[0159] The process for producing a film is not specifically restricted and any known manufacturing process can be used.

[0160] For example, a method for producing a thermoplastic resin film in which both surfaces are smooth can be described as a process in which melt forming is carried out using an extruder equipped with a T-nozzle with a predetermined lip width.

[0161] A method for producing a film in which irregularities are formed on one or both sides may, for example, be a method of transferring irregularities from a base die to the surface of a film by thermal processing, and with regard to productivity, the following method (i) or (ii) is preferred. In method (i) or (ii), continuous processing is made possible using a cylindrical base die, thereby considerably improving the productivity of a film with formed irregularities. (i) A method in which a film is passed between the base die roller and a printing roller, so that irregularities formed on the surface of the base die roller are continuously transferred to a surface of the film. (ii) A process in which a thermoplastic resin extruded from the nozzle of an extruder is passed between the base die roller and a pressure roller, so that, simultaneously with the forming of the thermoplastic resin into a film, irregularities formed on the surface of the base die roller are continuously transferred to the surface of the film-formed thermoplastic resin.

[0162] In method (i) or (ii) if a roller is used as the printing roller having irregularities on its surface, a thermoplastic resin film can be obtained which has irregularities on both sides.

[0163] The mold release film of the present invention has been described above with reference to the first embodiment; however, the present invention is not limited to the embodiment mentioned above. The respective designs and their combinations in the above embodiment are an example, and additions, omissions, substitutions, and other modifications of designs can be carried out within a range that does not deviate from the concept of the present invention. (Advantageous effects)

[0164] The mold tool release film of the present invention is less likely to become electrically charged or wavy, does not contaminate the mold tool and has excellent mold tool conformability.

[0165] That is, the release film of the present invention has a polymeric antistatic layer, which enables it to exhibit antistatic performance even when an inorganic filler, such as carbon black, is not present in the thermoplastic resin layers (the first thermoplastic resin layer and the second thermoplastic resin layer). Therefore, difficulties caused by charging and discharging during the removal of the mold release film during the manufacture of semiconductor packages can be avoided, such as the deposition of foreign materials on the electrically charged mold release film or the destruction of a semiconductor chip due to electrical discharge from the mold release film.Furthermore, it is less likely that shape anomalies of a semiconductor package or mold contamination will occur due to foreign materials deposited on the mold release film or detachment of the inorganic filler from the mold release film. Moreover, the mold release film of the present invention is less likely to become wavy and exhibits sufficient conformability, which is required in the manufacture of semiconductor packages. Therefore, adsorption of the mold release film onto the mold can be satisfactorily achieved during the manufacture of the semiconductor packages. [Semiconductor housing]

[0166] Semiconductor packages to be produced by the method for manufacturing a semiconductor package of the present invention, which will be described later, using the molding tool release film of the present invention, include integrated circuits in which semiconductor elements are integrated, such as transistors, diodes, etc., light-emitting diodes having a light-emitting element, etc.

[0167] The package form of an integrated circuit can be a form that completely covers the integrated circuit, or a form that partially covers it (leaving part of the integrated circuit exposed). Specific examples include a BGA (Ball Grid Array), a QFN (Quad Flat Non-leaded package), or a SON (Small Outline Non-leaded package).

[0168] For semiconductors, a package manufactured by batch encapsulation and singulation is preferred in terms of productivity. An example would be an integrated circuit where the encapsulation system is a MAP (Molded Array Packaging) system or a WL (Wafer Level Packaging) system.

[0169] The Fig. Figure 2 is a schematic cross-sectional view showing an example of a semiconductor package.

[0170] The semiconductor package 110 of this example comprises a substrate 10, a semiconductor chip (semiconductor element) 12 mounted on the substrate 10, a resin encapsulation section 14 for encapsulating the semiconductor chip 12, and an ink layer 16 formed on the upper surface 14a of the resin encapsulation section 14. The semiconductor chip 12 has a surface electrode (not shown), the substrate 10 has a substrate electrode (not shown) corresponding to the surface electrode of the semiconductor chip 12, and the surface electrode and the substrate electrode are electrically connected to each other by bond wires 18.

[0171] The thickness of the resin encapsulation section 14 (the shortest distance from the mounting surface of the semiconductor chip 12 of the substrate 10 to the upper surface 14a of the resin encapsulation section 14) is not specifically limited, but is preferably at least "the thickness of the semiconductor chip 12" and at most "the thickness of the semiconductor chip 12 + 1 mm", particularly preferably at least "the thickness of the semiconductor chip 12" and at most "the thickness of the semiconductor chip 12 + 0.5 mm".

[0172] The Fig.Figure 3 is a schematic cross-sectional view showing another example of a semiconductor package. The semiconductor package 120 of this example comprises a substrate 70, a semiconductor chip (semiconductor element) 72 mounted on the substrate 70, and an underfill (resin encapsulation section) 74. The underfill 74 fills a gap between the substrate 20 and the main surface of the semiconductor chip 72 (the surface on the side facing the substrate 70), leaving the back surface of the semiconductor chip 72 (the surface opposite the side facing the substrate 70) exposed. [Method for manufacturing a semiconductor package]

[0173] The method for manufacturing a semiconductor package according to the present invention is a method for manufacturing a semiconductor package comprising a semiconductor element and a resin encapsulation section formed from a curable resin for encapsulating the semiconductor element, characterized in that it a step of arranging the mold release film of the present invention on a surface of a mold which is to be in contact with the curable resin (where the second thermoplastic resin layer is in contact with the mold), such that the surface of the side of the first thermoplastic resin layer or the surface of the side of the first mold release film is directed towards the space in the mold, a step of arranging a substrate on which a semiconductor element is mounted in the mold and filling the space in the mold with a curable resin, which is then cured to form a resin encapsulation section, thereby obtaining an encapsulated body comprising the substrate, the semiconductor element and the resin encapsulation section, and includes a step of separating the encapsulated body from the mold.

[0174] For the method of manufacturing a semiconductor package of the present invention, a known manufacturing method can be used, except for the use of the mold release film of the present invention.

[0175] For example, the process for forming the resin encapsulation section can be a compression molding process or an injection molding process, and the apparatus used in such a case can be a known compression molding or injection molding device. The manufacturing conditions can also be identical to those in conventional semiconductor package manufacturing processes. (First embodiment)

[0176] As one embodiment of the method for manufacturing a semiconductor package, a case is described in detail in which a semiconductor package 110, as described above, is manufactured using the mold release film 1 described above as the mold release film. Fig. Figure 2 shows that the semiconductor package is manufactured by a compression molding process. The process for manufacturing a semiconductor package in this embodiment comprises the following steps (α1) to (α7). (α1) A step of arranging the mold release film 1 such that the mold release film 1 covers the mold cavity and the surface 2a on the side of the first thermoplastic resin layer 2 of the mold release film 1 is directed towards the space in the cavity (so that the surface 3a on the side of the second thermoplastic resin layer 3 is directed towards the cavity surface). (α2) One step of vacuum suction of the mold tool release film 1 to the side of the cavity surface of the mold tool. (α3) A step of filling the cavity with a curable resin. (α4) A step of arranging a substrate 10 comprising a plurality of semiconductor chips 12 mounted on it at a predetermined position in the cavity and of jointly encapsulating the plurality of semiconductor chips 12 by the curable resin, so that a resin encapsulation section is formed, thereby obtaining a jointly encapsulated body comprising the substrate 10, the plurality of semiconductor chips 12 mounted on the substrate 10 and the resin encapsulation section jointly encapsulating the plurality of semiconductor chips 12. (α5) A step of removing the jointly encapsulated body from the mold. (α6) A step of cutting the substrate 10 and the resin encapsulation section of the jointly encapsulated body, such that the plurality of semiconductor chips 12 are separated, so that individual encapsulated bodies are obtained, each comprising the substrate 10, at least one semiconductor chip 12 mounted on the substrate 10, and a resin encapsulation section 14 encapsulating the semiconductor chip 12. (α7) A step of forming a printing ink layer 16 on the surface of the resin encapsulation section 14 of the isolated encapsulated body using a printing ink, so that a semiconductor package 1 is obtained. Forming tool:

[0177] In the first embodiment, a forming tool known as a forming tool used for a compression molding process can be used, and, for example, as described in the Fig.Figure 4 shows a forming tool comprising a stationary upper tool 20, a lower cavity element 22 and a movable frame-shaped lower tool 24 arranged on the circumference of the lower cavity element 22.

[0178] In the stationary upper tool 20, a vacuum vent (not shown) is configured such that the substrate 10 is adsorbed onto the stationary upper tool 20 by drawing in air between the substrate 10 and the stationary upper tool 20. Furthermore, a vacuum vent (not shown) is configured in the lower cavity element 22 for adsorbing the mold release film 1 onto the lower cavity element 22 by drawing in air between the mold release film and the lower cavity element 22.

[0179] In this mold, a cavity 26 is formed by the upper surface of the lower cavity element 22 and the inner side surfaces of the movable lower tool 24 in a shape corresponding to the shape of the resin encapsulation section formed in step (α4). Hereinafter, the upper surface of the lower cavity element 22 and the inner side surfaces of the movable lower tool 24 can also be referred to collectively as the cavity surface. Step (α1):

[0180] On the movable lower tool 24, the mold release film 1 is arranged such that it covers the upper surface of the lower cavity element 22. The mold release film 1 is arranged such that the surface 3a of the side of the second thermoplastic resin layer 3 faces downwards (in the direction towards the lower cavity element 22).

[0181] The mold release film 1 is unwound from an unwind roller (not shown) and wound onto a winding roller (not shown). The mold release film 1 is pulled by the unwind roller and the winding roller and is therefore arranged in a stretched state on the movable lower tool 24. Step (α2):

[0182] Separately, by vacuum suction through a vacuum vent (not shown) of the lower cavity element 22, the space between the upper surface of the lower cavity element 22 and the mold release film 1 is evacuated, so that the mold release film is stretched, deformed, and vacuum-adsorbed onto the upper surface of the lower cavity element 22. Furthermore, by tightening the frame-shaped movable lower tool 24, which is arranged on the circumference of the lower cavity element 22, the mold release film 1 is pulled from all directions, so that it is under tension.

[0183] The mold release film 1, depending on its strength and thickness, does not necessarily have to be in close contact with the cavity surface in a high-temperature environment and on the shape of the concave section formed by the upper surface of the lower cavity element 22 and the inner side surfaces of the movable lower tool 24. At the vacuum suction stage in step (α2), as described in the Fig. As shown in Figure 4, a small cavity may remain between the mold release film 1 and the cavity surface. Step (α3):

[0184] As it is in the Fig.As shown in Figure 4, a curable resin 40 is applied in a suitable quantity to the mold release film 1 in the cavity 26 by an application device (not shown). Separately, a substrate 10, which has a plurality of semiconductor elements 12 mounted on it, is vacuum adsorbed onto the lower surface of the stationary upper tool 20 by vacuum suction through a vacuum vent (not shown) of the stationary upper tool 20.

[0185] Various curable resins, such as those used in the manufacture of semiconductor packages, etc., can be used as curable resin 40. A thermosetting resin, such as an epoxy resin or a silicone resin, is preferred, and an epoxy resin is particularly preferred.

[0186] Examples of epoxy resins include SUMIKON EME G770H type Fver. GR, manufactured by Sumitomo Bakelite Co., Ltd., and T693 / R4719-SP10, manufactured by Nagase ChemteX Corporation. Examples of commercially available silicone resins include LPS-3412AJ and LPS-3412B, manufactured by Shin-Etsu Chemical Co., Ltd.

[0187] The curable resin 40 can contain carbon black, quartz glass, crystalline silicon dioxide, aluminum oxide, silicon nitride, aluminum nitride, etc. Here, a case of filling with a solid resin as the curable resin 40 has been described; however, the invention is not limited to this, and a curable liquid resin can also be used. Step (α4):

[0188] As it is in the Fig.As shown in Figure 5, in a state where the curable resin 40 is applied to the mold release film 1 in the cavity 26, the lower cavity element 22 and the movable lower tool 24 are raised and clamped to the stationary lower tool 20 for mold clamping. Then, as shown in the Fig. As shown in Figure 6, only the lower cavity element 22 is raised and at the same time the mold tool is heated so that the curable resin 40 is cured to form a resin encapsulation section for the common encapsulation of the majority of semiconductor chips 12.

[0189] In step (α4), the pressure applied at the moment the lower cavity element 22 is lifted further forces the curable resin 40, which is filled into the cavity 26, towards the cavity surface. This stretches and deforms the mold release film 1 so that it is in close contact with the cavity surface. Therefore, the resin encapsulation section, which has a shape corresponding to the shape of the cavity 26, is formed.

[0190] The heating temperature of the mold, i.e., the heating temperature of the curable resin 40, is preferably from 100 to 185 °C, more preferably from 140 to 175 °C. If the heating temperature is at least the lower limit in the aforementioned range, the productivity of the semiconductor package 110 is improved. If the heating temperature is at most the upper limit in the aforementioned range, decomposition of the curable resin 40 is prevented.

[0191] With a view to suppressing a change in the shape of the resin encapsulation section 14 due to thermal expansion of the curable resin 40, the heating is preferably carried out at the lowest possible temperature within the aforementioned range when the protection of the semiconductor housing 110 is particularly required. Step (α5):

[0192] The forming tool consisting of the stationary upper tool 20, the lower cavity element 22 and the movable lower tool 24 is opened and the jointly encapsulated body is removed.

[0193] Simultaneously with the separation of the jointly encapsulated body, the used section of the mold release film 1 is conveyed to a winding reel (not shown), and an unused section of the mold release film 1 is unwound from an unwinding reel (not shown). The thickness of the mold release film 1 at the time of transport from the unwinding reel to the winding reel is preferably at least 25 µm. If the thickness is less than 25 µm, wrinkling is likely to occur during transport of the mold release film 1. If wrinkles form in the mold release film 1, such wrinkles are likely to be transferred to the resin encapsulation section 14, resulting in a defective product. If the thickness is at least 25 µm, sufficient tension can be exerted on the mold release film 1 to prevent wrinkling. Step (α6):

[0194] The substrate 10 and the resin encapsulation section of the jointly encapsulated body, which has been removed from the mold, were cut (separated) so that the majority of semiconductor chips 12 are separated, so that individual encapsulated bodies are obtained, each comprising the substrate 10, at least one semiconductor chip 12 and a resin encapsulation section 14 encapsulating the semiconductor chip 12.

[0195] Such singulation can be carried out using a known method, such as a sawing process (also known as a "dicing" process). The sawing process is a method of cutting an object by rotating a saw blade. Typically, a rotating blade (diamond saw blade) is used, which has diamond powder sintered onto the outer circumference of a disc. Singulation by the sawing process can be carried out, for example, by a method in which the jointly encapsulated body, as the object to be cut, is fixed on the processing table by means of a clamping device, and the saw blade is rotated in a state where there is space for inserting the saw blade between the clamping device and the cutting area of ​​the object to be cut.

[0196] In step (α6) after the step (cutting step) of cutting the jointly encapsulated body as described above, a foreign material removal step of moving the processing table can be included while a liquid is supplied to the object to be cut from a nozzle located at a position separate from the enclosure for covering the saw blade. Step (α7):

[0197] On the upper surface 14a (the surface that was in contact with the mold release film 1) of the resin encapsulation section 14 of the singulated encapsulated body obtained in step (α6), a printing ink is applied to form a printing ink layer 16 to indicate optional information, so that a semiconductor package 110 is obtained.

[0198] The information to be conveyed by ink layer 16 is not specifically limited and can include a serial number, manufacturer information, component type, etc. The method for applying the ink is also not specifically limited and can include various printing methods such as inkjet printing, screen printing, transfer from a rubber plate, etc.

[0199] The printing ink is not specifically limited and can be selected from known printing inks in a suitable manner. With regard to a high curing speed, reduced bleed-through on the housing, and minimal displacement of the housing (since no hot air is used), a method is preferred for forming the printing ink layer 16 in which a light-curable printing ink is used. The printing ink is applied to the upper surface 14a of the resin encapsulation section 14 by an inkjet process and cured by irradiation with light.

[0200] A typical light-curable printing ink is one containing a polymerizable compound (monomer, oligomer, etc.). Depending on the requirements, the ink can be modified with a colorant such as a pigment or dye, a liquid medium (solvent or dispersant), a polymerization inhibitor, a photopolymerization initiator, and various other additives. Other additives include, for example, a lubricant, a polymerization accelerator, a penetration enhancer, a wetting agent (humectant), a fixative, a fungicide, an antiseptic, an antioxidant, a radiation absorber, a chelating agent, a pH adjuster, a thickener, etc.

[0201] Examples of light used to cure light-curable printing ink include ultraviolet rays, visible rays, infrared rays, an electron beam, or electron beams.

[0202] Examples of light sources for ultraviolet rays include a germicidal lamp, an ultraviolet fluorescent lamp, a carbon arc lamp, a xenon lamp, a high-pressure mercury lamp for copying, a medium-pressure or high-pressure mercury lamp, an ultra-high-pressure mercury lamp, an electrodeless lamp, a metal halide lamp, an ultraviolet light-emitting diode, an ultraviolet laser diode, or natural light.

[0203] Light irradiation can be carried out under normal pressure or reduced pressure. It can also be performed in air or in an inert gas atmosphere, such as a nitrogen or carbon dioxide atmosphere. (Second embodiment)

[0204] As a further embodiment of the method for manufacturing a semiconductor package, a case of manufacturing the semiconductor package 110, as described in the Fig.2 is shown, which is described in detail by means of an injection molding process using the mold release film 1 described above as the mold release film.

[0205] The method for manufacturing a semiconductor package in this embodiment comprises the following steps (β1) to (β7): (β1) A step of arranging the mold release film 1 such that the mold release film 1 covers the mold cavity and the surface 2a on the side of the first thermoplastic resin layer 2 of the mold release film 1 is directed towards the space in the cavity (so that the surface 3a on the side of the second thermoplastic resin layer 3 is directed towards the cavity surface). (β2) One step of vacuum suction of the mold tool release film 1 to the side of the cavity surface of the mold tool. (β3) A step of arranging a substrate 10, which has a plurality of semiconductor chips 12 arranged on it, at the specified position in the cavity. (β4) A step of filling the cavity with a curable resin and jointly encapsulating the plurality of semiconductor chips 12 with the curable resin to form a resin encapsulation section, so that a jointly encapsulated body is obtained comprising the substrate 10, the plurality of semiconductor chips 12 mounted on the substrate 10 and the encapsulated section jointly encapsulating the plurality of semiconductor chips 12. (β5) A step of removing the jointly encapsulated body from the molding tool. (β6) A step of cutting the substrate 10 and the resin encapsulation section of the jointly encapsulated body, such that the plurality of semiconductor chips 12 are separated, so that individual encapsulated bodies are obtained, each comprising the substrate 10, at least one semiconductor chip 12 mounted on the substrate 10, and a resin encapsulation section 14 encapsulating the semiconductor chip 12. (β7) A step of forming a printing ink layer on the surface of the resin encapsulation section 14 of the isolated encapsulated body using a printing ink, so that a semiconductor package 1 is obtained. Forming tool:

[0206] In the second embodiment, a mold can be used that is known as a mold for an injection molding process and can, for example, be used as described in the Fig.Figure 7 shows a forming tool comprising an upper tool 50 and a lower tool 52. The upper tool 50 includes a cavity 54 in a shape corresponding to the shape of the resin encapsulation section 14 to be formed in step (α4), and a concave resin injection section 60 for guiding a curable resin 40 to the cavity 54. The lower tool 52 includes a substrate arrangement section 58 for arranging the substrate 10, which has the semiconductor chip 12 mounted thereon, and a resin arrangement section 62 for arranging a curable resin 40. Furthermore, the resin arrangement section 62 provides a piston 64 for pushing a curable resin 40 to the resin injection section 60 of the upper tool 50. Step (β1):

[0207] As it is in the Fig.As shown in Figure 8, the mold release film 1 is arranged so that it covers the cavity 54 of the upper mold 50. The mold release film 1 is preferably arranged so that it covers the entire cavity 54 and the resin injection section 60. The mold release film 1 is drawn through the unwind roller (not shown) and the rewind roller (not shown) and is thereby arranged so that it covers the cavity 54 of the upper mold 50 in a stretched state. Step (β2):

[0208] As it is in the Fig.As shown in Figure 9, the space between the mold release film 1 and the cavity surface 56 and the space between the mold release film 1 and the inner wall of the resin injection section 60 are vacuum-sealed by vacuum suction through a groove (not shown) formed outside the cavity 54 of the upper tool 50, so that the mold release film is stretched, deformed and vacuum-adsorbed onto the cavity surface 56 of the upper tool 50.

[0209] Depending on its strength or thickness, the mold release film 1 does not always have to be in close contact with the cavity surface 56 in a high-temperature environment or the shape of the cavity 54. As shown in the Fig. As shown in Figure 9, a small cavity may remain between the mold tool release film 1 and the cavity surface 56 at the vacuum suction stage in step (β2). Step (β3):

[0210] As it is in the Fig. As shown in Figure 10, the substrate 10, which has a plurality of semiconductor chips 12 mounted on it, is arranged in the substrate assembly section 58, and the upper tool 50 and the lower tool 52 are clamped such that the plurality of semiconductor chips 12 are arranged at a predetermined position within the cavity 54. Furthermore, a curable resin 40 is pre-arranged on the piston 64 of the resin assembly section 62. The curable resin 40 can be identical to the curable resin 40 referred to in method (α). Step (β4):

[0211] As it is in the Fig.As shown in Figure 11, the piston 64 of the lower tool 52 is raised so that the curable resin 40 is filled into the cavity 54 through the resin injection section 60. The mold is then heated to cure the curable resin 40, thereby encapsulating the majority of semiconductor chips 12 to form a resin encapsulation section.

[0212] In step (β4), when the curable resin 40 is filled into the cavity 54, the mold release film 1 is further pressed, stretched, and deformed by the resin pressure against the side of the cavity surface 56, so that it will be in close contact with the cavity surface 56. Therefore, a resin encapsulation section 14 with a shape corresponding to the shape of the cavity 54 is formed.

[0213] The heating temperature of the mold tool for curing the curable resin 40, i.e., the heating temperature of the curable resin 40, is preferably within the same range as the temperature range in the method (α).

[0214] The resin pressure at the time of filling with the curable resin 40 is preferably from 2 to 30 MPa, particularly preferably from 3 to 10 MPa. If the resin pressure is at least the lower limit in the aforementioned range, it is less likely that a disadvantage such as insufficient filling of the curable resin 40 will occur. If the resin pressure is at most the upper limit in the aforementioned range, a semiconductor package 110 of excellent quality can easily be obtained. The resin pressure of the curable resin 40 can be adjusted by the piston 64. Step (β5):

[0215] As it is in the Fig.As shown in Figure 12, a jointly encapsulated body 110A, comprising the substrate 10, the plurality of semiconductor chips 12 mounted on the substrate 10, and the resin encapsulation section 14A, which jointly encapsulates the plurality of semiconductor chips 12, is removed from the mold. The cured product 19, which contains the curable resin 40 that has been cured in the resin injection section 60, is removed from the mold together with the jointly encapsulated body 110A in a state where it is connected to the resin encapsulation section 14A of the jointly encapsulated body 110A. Therefore, the cured product 19, which is connected to the removed jointly encapsulated body 110A, is cut off, so that the jointly encapsulated body 110A is obtained. Step (β6):

[0216] The substrate 10 and the resin encapsulation section 14A of the jointly encapsulated body 110A obtained in step (β5) are cut (separated) such that the majority of semiconductor chips 12 are separated, resulting in individual encapsulated bodies, each comprising the substrate 10, at least one semiconductor chip 12, and a resin encapsulation section 14 encapsulating the semiconductor chip 12. Step (β6) can be carried out in the same manner as step (α6). Step (β7):

[0217] On the upper surface 14a (the surface that was in contact with the first surface of the mold release film 1) of the resin encapsulation section 14 of the resulting singular encapsulated body, a printing ink is applied to form a printing ink layer 16 for specifying any information, so that a semiconductor package 110 is obtained. Step (β7) can be carried out in the same way as step (α7). (Third embodiment)

[0218] As a further embodiment of the method for manufacturing a semiconductor package, a case of manufacturing a semiconductor package 120, as described in the Fig. 3 is shown, which is described in detail by means of an injection molding process using the mold release film 1 described above as the mold release film.

[0219] The method for manufacturing a semiconductor package in this embodiment comprises the following steps (γ1) to (γ5): (γ1) A step of arranging the mold release film 1 such that the mold release film 1 covers the cavity of an upper tool of the mold comprising an upper tool and a lower tool and such that the surface 2a on the side of the first thermoplastic resin layer 2 of the mold release film 1 is directed towards the space in the cavity (such that the surface 3a on the side of the second thermoplastic resin layer 3 is directed towards the cavity surface of the upper tool). (γ2) One step of vacuum suction of the mold tool release film 1 to the side of the cavity surface of the upper tool. (γ3) A step of arranging a substrate 70 having a semiconductor chip 72 arranged thereon on the lower tool and clamping the upper tool and the lower tool so that the mold tool parting film 1 is brought into close contact with the back surface of the semiconductor chip 72 (the surface opposite the side of the substrate 70). (γ4) A step of filling a curable resin into the cavity between the upper tool and the lower tool to form the underfill 74, thereby obtaining a semiconductor housing 120 (encapsulated body) comprising the substrate 70, the semiconductor chip 72 and the underfill 74. (γ5) One step of removing the semiconductor package 120 from the mold. Forming tool:

[0220] The same forming tool as in the second embodiment can be used as the forming tool in the third embodiment. Step (γ1):

[0221] As it is in the Fig. As shown in Figure 13, the mold release film 1 is arranged so that it covers the cavity 54 of the upper tool 50. Step (γ1) can be carried out in the same way as step (β1). Step (γ2):

[0222] By vacuum suction through a groove (not shown) formed outside the cavity 54 of the upper tool 50, the space between the mold release film 1 and the cavity surface 56 and the space between the mold release film 1 and the inner wall of the resin injection section 60 are evacuated, so that the mold release film 1 is stretched, deformed, and vacuum-adsorbed onto the cavity surface 56 of the upper tool 50. Step (γ2) can be carried out in the same way as step (β2). Step (γ3):

[0223] As it is in the Fig.As shown in Figure 14, a substrate 70, on which the semiconductor chip 72 is mounted, is arranged on the substrate arrangement section 58 of the lower tool 52.

[0224] Then the upper tool 50 and the lower tool 52 are clamped so that the semiconductor chip 12 is positioned at a predetermined location in the cavity 54, and simultaneously the mold release film is brought into close contact with the back surface of the semiconductor chip 72 (the surface opposite the side of the substrate 70). Furthermore, a curable resin 40 is pre-applied to the piston 64 of the resin assembly section 62.

[0225] The curable resin 40 can be identical to the curable resin 40 mentioned in the procedure (α). Step (γ4):

[0226] As it is in the Fig.As shown in Figure 15, the piston 64 of the lower tool 52 is raised so that the curable resin 40 is filled into the cavity 54 through the resin injection section 60. The mold is then heated to cure the curable resin 40, forming an underfill 74. Step (γ4) can be carried out in the same way as step (β4). Step (γ5):

[0227] As it is in the Fig.As shown in Figure 16, the semiconductor package 120, which comprises the substrate 70, the semiconductor chip 72 mounted on the substrate 70, and the underfill 74 encapsulating the side faces and the bottom face of the semiconductor chip 72, is removed from the mold. The cured product 76, which contains the curable resin 40 that has cured in the resin injection section 60, is removed from the mold together with the semiconductor package 12 in a state where it is bonded to the underfill 74 of the semiconductor package 12. Therefore, the cured product 76, which is bonded to the removed semiconductor package 120, is cut off, thus obtaining the semiconductor package 120.

[0228] In this embodiment, in step (γ4), the curable resin 40 is injected in a state such that a section (the back surface) of the semiconductor chip 72 is in direct contact with the mold release film 1. Consequently, the curable resin will not be in contact with the section of the semiconductor chip 72 that is in direct contact with the mold release film 1, thus obtaining a semiconductor housing 120 in which part of the semiconductor chip 72 is exposed.

[0229] The method for manufacturing a semiconductor package of the present invention has been described above with reference to the first to third embodiments; however, the present invention is not limited to the aforementioned embodiments. The respective designs and their combinations, etc., in the aforementioned embodiments are exemplary, and additions, omissions, substitutions, and other modifications are possible within a range that does not deviate from the concept of the present invention.

[0230] For example, the first embodiment shows an example where step (α6) and step (α7) are performed in this order after step (α5), but step (α6) and step (α7) can also be performed in reverse order. That is, a printing ink layer can be formed on the surface of the resin encapsulation section of the jointly encapsulated body, which has been removed from the mold, using a printing ink, and then the substrate and the resin encapsulation section of the jointly encapsulated body can be cut.

[0231] Accordingly, the second embodiment shows an example in which step (β6) and step (β7) are performed in this order after step (β5), but step (β6) and step (β7) can also be performed in reverse order. That is, a printing ink layer can be formed on the surface of the resin encapsulation section of the jointly encapsulated body, which has been removed from the mold, using a printing ink, and then the substrate and the resin encapsulation section of the jointly encapsulated body can be cut.

[0232] The time sequence for the detachment of the resin encapsulation section from the mold release film is not limited to the time of removing the resin encapsulation section from the mold; the resin encapsulation section can be removed from the mold together with the mold release film, and then the mold release film can be detached from the resin encapsulation section.

[0233] The distances between respective adjacent semiconductor chips 12 of the jointly encapsulated plurality of semiconductor chips 12 can be uniform or non-uniform. In view of the fact that the encapsulation can be carried out uniformly and that a load is applied uniformly to the plurality of semiconductor chips 12 (i.e., the load is minimized), it is preferred to make the distances between respective adjacent semiconductor chips 12 of the plurality of semiconductor chips 12 the same.

[0234] Furthermore, semiconductor packages to be produced by the method for producing a semiconductor package of the present invention are not limited to the semiconductor packages 110 and 120.

[0235] Depending on the semiconductor package to be manufactured, steps (α6) and (α7) in the first embodiment and steps (β6) and (β7) in the second embodiment may not need to be performed. For example, the shape of the resin encapsulation section is not limited to those described in the Fig. 2 and Fig. Figure 3 shows the components, and there may be a difference in height, etc. The semiconductor elements to be encapsulated in the resin encapsulation section can be one or more. The ink layer is not essential.

[0236] In the case of manufacturing a light-emitting diode as a semiconductor package, a resin encapsulation section also acts as a lens unit, and typically no ink layer is formed on the surface of the resin encapsulation section. Various lens shapes can be used for such a lens unit, including hemispherical, bullet-shaped, Fresnel-type, semi-cylindrical, and essentially hemispherical lens array types, etc. EXAMPLES

[0237] The present invention is described in detail below with reference to examples. However, the present invention is not limited by the following description. Of the following Examples 1 to 13, Examples 1 to 5 and 7 to 9 are examples of the present invention, Examples 10 to 13 are comparative examples, and Example 6 is a reference example. The materials and evaluation methods used in the examples are shown below. [Materials used]<Thermoplastische Harze>

[0238] ETFE (1): Copolymer of tetrafluoroethylene / ethylene / PFBE = 52.5 / 46.3 / 1.2 (molar ratio) (MFR: 12 g / 10 min) obtained in the preparation example 1 described below.

[0239] ETFE (2): Copolymer of tetrafluoroethylene / ethylene / PFBE = 56.3 / 40.2 / 3.5 (molar ratio) (MFR: 12.5 g / 10 min) obtained in the preparation example 2 described below.

[0240] PBT: Polybutylene terephthalate, “NOVADURAN 5020” (manufactured by Mitsubishi Engineering Plastics Corporation).

[0241] Polymethylpentene: “TPX MX004” (manufactured by Mitsui Chemicals, Inc.). <Herstellungsbeispiel 1: Herstellung von ETFE (1)>

[0242] A polymerization tank with an internal volume of 1.3 liters, equipped with a stirrer, was purged of air, 881.9 g of 1-hydrotridecafluorohexane, 335.5 g of 1,3-dichloro-1,1,2,2,3-pentafluoropropane (trade name "AK225cb", manufactured by Asahi Glass Company, Limited, hereinafter referred to as AK225cb) and 7.0 g of CH2=CHCF2CF2CF2CF3 (PFBE) were introduced, 165.2 g of TFE and 9.8 g of ethylene (hereinafter referred to as E) were injected, the interior of the polymerization tank was heated to 66 °C and 7.7 ml of a 1 wt% AK225cb solution of tert-butyl peroxypivalate (hereinafter referred to as PBPV) were introduced as a polymerization initiator solution to start the polymerization.

[0243] To maintain constant pressure during polymerization, a monomer mixture gas with a molar ratio of TFE / E = 54 / 46 was continuously introduced. Simultaneously with the introduction of the monomer mixture gas, PFBE was continuously introduced in an amount corresponding to 1.4 mol% of the total molar number of TFE and E. 2.9 hours after the initiation of polymerization, at the time 100 g of the monomer mixture gas had been introduced, the internal temperature of the polymerization tank was lowered to room temperature, and the pressure of the polymerization tank was simultaneously reduced to atmospheric pressure.

[0244] The resulting slurry was then filtered through a glass filter and the solids content was collected and dried at 150 °C for 15 hours, yielding 105 g ETFE (1). <Herstellungsbeispiel 2: Herstellung von ETFE (2)>

[0245] 90 g of ETFE (2) were obtained in the same manner as in Production Example 1, except that the internal volume of the polymerization tank was changed to 1.2 liters, the amount of 1-hydrotridecafluorohexane to be introduced before the start of polymerization was changed from 881.9 g to 0 g, the amount of AK225cb was changed from 335.5 g to 291.6 g, the amount of PFBE was changed from 16.0 g to 7.0 g, the amount of TFE was changed from 165.2 g to 186.6 g, the amount of E was changed from 9.8 g to 6.4 g, the amount of the 1 wt% AK225cb solution of PBPV was changed from 5.8 ml to 5.3 ml, and the molar ratio of TFE / E in the monomer mixture gas continuously supplied during polymerization was changed from 58 / 42 was changed to 54 / 46, the amount of PFBE (relative to the total number of moles of TFE and E) was changed from 3.6 mol% to 0.8 mol%, and after 3 hours from the initiation of polymerization at that time,when 90 g of the monomer mixture gas have been introduced and the internal temperature of the polymerization tank has been lowered to room temperature. <Thermoplastische Harzfilme>

[0246] ETFE film (1-1): Thickness 30 µm. One side has irregularities with a surface roughness (Ra) of 1.5, and the other side is smooth with a surface roughness (Ra) of 0.1. The ETFE film (1-1) was produced by the following process.

[0247] ETFE (1) was extruded at 320 °C through an extruder in which the lip opening was adjusted to produce a film thickness of 30 µm. The ETFE film was produced by adjusting the base die roller, the film forming speed, and the compression pressure.

[0248] ETFE film (1-2): Thickness 25 µm. Both sides are smooth, with a surface roughness (Ra) of 0.1 on both sides. The ETFE film (1-2) was produced in the same way as the ETFE film (1-1), except that the base die roller, the film forming speed, and the compression pressure condition were adjusted.

[0249] ETFE film (2-1): Thickness 25 µm. Both sides are smooth, with a surface roughness (Ra) of 0.1 on both sides. The ETFE film (2-1) was produced in the same way as the ETFE film (1-2), except that ETFE (2) was used instead of ETFE (1) and the extrusion temperature was changed to 300 °C.

[0250] ETFE film (1-3): Thickness 12 µm. Both sides are smooth, with a surface roughness (Ra) of 0.1 on both sides. The ETFE film (1-3) was produced in the same way as the ETFE film (1-2), except that the conditions were adjusted to achieve a thickness of 12 µm.

[0251] ETFE film (1-4): Thickness 50 µm. Both sides are smooth, with a surface roughness (Ra) of 0.1 on both sides. It was produced in the same way as ETFE film (1-2), except that the conditions were adjusted to achieve a thickness of 50 µm.

[0252] Furthermore, each of the films was corona treated so that the wetting voltage based on ISO8296: 1987 (JIS K6768 1999) is at least 40 mN / m.

[0253] PBT film (1-1): Thickness 25 µm. One side has irregularities with a surface roughness (Ra) of 0.8, and the other side is smooth with a surface roughness (Ra) of 0.1. The PBT film (1-1) was produced by the following procedure.

[0254] The polybutylene terephthalate resin "NOVADURAN 5020" (manufactured by Mitsubishi Engineering-Plastics Corporation) was extruded at 280 °C through an extruder with the die opening adjusted to produce a film thickness of 25 µm. The PBT film was produced by adjusting the base die roller, film formation speed, and squeeze pressure.

[0255] PBT film (1-2): Thickness 50 µm. Irregularities are present on both sides and Ra on both sides is 1.5. The PBT film (1-2) was produced in the same way as the PBT film (1-1), except that the base die roller, the film forming speed and the squeeze pressure condition were adjusted.

[0256] TPX film (1-1): Thickness 25 µm. One side has irregularities with a surface roughness (Ra) of 0.8, and the other side is smooth with a surface roughness (Ra) of 0.1. The TPX film (1-1) was produced by the following procedure.

[0257] The polymethylpentene resin "TPX MX004" (manufactured by Mitsubishi Engineering-Plastics Corporation) was extruded at 280 °C through an extruder with the die opening adjusted to produce a film thickness of 25 µm. The TPX film was produced by adjusting the base die roller, film formation speed, and squeeze pressure. It was corona treated to achieve a wetting stress of at least 40 mN / m, based on ISO 8296:1987 (JIS K6768 1999).

[0258] PET film (1-1): Thickness 25 µm. “Tetoron G2 25 µm” (manufactured by Teijin DuPont Films) was used. Both sides are flat, with a surface roughness (Ra) of 0.2 on both sides.

[0259] PET film (1-2): Thickness 50 µm. “Tetoron G2 50 µm” (manufactured by Teijin DuPont Films) was used. Both sides are flat, with a surface roughness (Ra) of 0.2 on both sides.

[0260] Polyamide film (1-1): 25 µm thick. “Diamiron CZ” (manufactured by Mitsubishi Plastics Co., Ltd.) was used. Both sides are flat, with a surface roughness (Ra) of 0.1 on both sides.

[0261] ETFE (3 parts carbon black kneaded in) film (1-1): thickness 50 µm. Irregularities are present on both sides and Ra on both sides is 1.5. The ETFE (3 parts carbon black kneaded in) film (1-1) was produced using the following method.

[0262] 100 parts by mass of ETFE granules (1) were mixed with 3 parts by mass of carbon black “DENKA BLACK granules” (manufactured by Denki Kagaku Kogyo KK), and kneaded with a twin-screw extruder at 320 °C to obtain a mixed granulate. The granulate was then melt extruded through an extruder at 320 °C to produce the ETFE (3 parts by mass of carbon black incorporated) film. <Weitere Materialien>

[0263] Bondeip (BONDEIP, Trade Name)-PA100: Bondeip (Trade Name)-PA100-Main Agent, Bondeip (Trade Name)-PA100-Curing Agent (manufactured by Konishi Co., Ltd.).

[0264] Conductive polymer A: Polypyrrole dispersion “CORERON YE” (manufactured by Kaken Sangyo Co., Ltd.).

[0265] Adhesive composition 1: Polyester polyol “CRISVON NT-258” (manufactured by DIC Corporation) as the main agent and hexamethylene diisocyanate “Coronate 2096” (manufactured by Nippon Polyurethane Industry Co., Ltd.) as the curing agent. Pelestat (trade name) NC6321: Resin with a polyethylene oxide chain. [Method for producing a mold release film] (dry lamination)

[0266] In all examples, dry lamination was carried out by applying each coating solution by engraving onto a substrate (a film corresponding to the second thermoplastic resin layer) under conditions of a substrate width of 1000 mm, a conveying speed of 20 m / min, a drying temperature of 80 to 100 °C, a laminate roller temperature of 25 °C and a pressure of 3.5 MPa. [Evaluation method](Detachment strength at 180 °C)

[0267] Of the mold release films produced in the respective examples, a 180-degree peel test was performed according to JIS K6854-2: 1999 for a mold release film with a film structure in which two films (a first thermoplastic resin layer and a second thermoplastic resin layer) were dry laminated, whereby the peel strength (N / cm) at 180 °C between the two thermoplastic films was measured. (a) The produced mold release film was cut to a width of 25 mm × a length of 15 cm so that an evaluation sample was obtained. (b) In a tank at constant temperature, heated to 180 °C, the second thermoplastic resin layer of the evaluation specimen was clamped by a lower jaw using a tensile testing machine (RTC-1310A manufactured by Orientec Co.), the first thermoplastic resin layer was clamped by the upper jaw, and the peel strength at an angle of 180 degrees was measured by moving the upper jaw upwards at a speed of 100 mm / min. (c) In the force (N) clamping movement distance curve, an average value of the peel strength (N / cm) was obtained from the clamping movement distance of 30 mm to 100 mm. (d) An average peel strength was obtained from five evaluation samples produced from the same mold release film. This value was used as the peel strength at 180 °C of the mold release film. (Surface resistance of an antistatic layer)

[0268] In each example, after the formation of an antistatic layer on the second thermoplastic resin layer without laminating the first thermoplastic resin layer, the surface resistance was measured according to IEC 60093. For example 7, where no antistatic layer was formed, the surface resistance of the mold release film was measured directly. The measurement environment was 23 °C and 50% relative humidity. (modulus of elasticity)

[0269] The storage elasticity modulus E' (25) at 25 °C and the storage elasticity modulus E' (180) at 180 °C of films corresponding to the respective layers of the first thermoplastic resin layer and the second thermoplastic resin layer were measured by the following method.

[0270] Using a SOLID L-1 dynamic viscoelasticity measuring device (manufactured by Toyo Seiki Co., Ltd.), the storage elasticity modulus E' was measured according to IS06721-4: 1994 (JIS K7244-4: 1999). E', measured at temperatures of 25 °C and 180 °C by setting the frequency to 10 Hz, the static force to 0.98 N, and the dynamic displacement to 0.035%, and increasing the temperature at a rate of 2 °C / min from 20 °C, was used as the storage elasticity modulus E' (25) at 25 °C and the storage elasticity modulus E' (180) at 180 °C, respectively. (Ash adhesion test)

[0271] A 1 cm thick, square sponge (10 cm × 10 cm) with an 8 cm × 8 cm square hole open in the center was placed on a metal substrate. One gram of cigarette ash was then placed at the center of the hole, and a mold release film was applied to the sponge with the side of the first thermoplastic resin layer facing down. The setup was left for one minute at a temperature of 23–26 °C and a relative humidity of 50 ± 5%. The presence or absence of ash adhesion to the mold release film was then visually inspected. The results were evaluated according to the following standards: the lower the ash adhesion, the lower the probability of the mold release film becoming electrically charged. ◯ (Good): The ash doesn't stick at all. × (Bad): The ash sticks. (180 °C acclimatization test)

[0272] The one in Fig. The device shown in Figure 17 comprises a frame element made of stainless steel (thickness: 3 mm) 90 with a square hole of 11 mm × 11 mm in the center, a clamping device 92 with a space S which can accommodate the frame element 90, a weight 94 which is arranged on the clamping device 92, and a heating plate 96 which is arranged below the clamping device 92.

[0273] The clamping device 92 comprises an upper element 92A and a lower element 92B. It is designed such that, by sandwiching a mold release film 30, which is to be evaluated, between the upper element 92A and the lower element 92B and by positioning the weight 94, the mold release film 30 is fixed and an airtight space S is formed. At this point, the frame element 90 is in a state in which a stainless steel frame (10.5 mm × 10.5 mm) 98 and a stainless steel mesh (10.5 mm × 10.5 mm) 80 are received in the hole, on the side of the upper element 92A of the clamping device 92 and in contact with the mold release film 30.

[0274] A drain opening 84 is formed on the upper surface of the upper element 92A, and a stainless steel mesh (10.5 mm × 10.5 mm) 82 is arranged on the opening surface of the side of the chamber S of the drain opening 84. Furthermore, a through-hole 86 is formed at the position of the weight 94 corresponding to the drain opening 84, and a line L1 is connected to the drain opening 84 through the through-hole 86. A vacuum pump (not shown) is connected to the line L1, so that the chamber S in the clamping device 92 can be evacuated by actuating the vacuum pump. A line L2 is connected to the lower element 92B, so that compressed air can be supplied to the chamber S in the clamping device 92 via the line L2.

[0275] In this device, a small gap exists between the inner surface of the hole in the frame element 90 and the outer edge of each of the mesh 80 and the frame 98, allowing the mesh 80 and the frame 98 to move vertically within the hole in the frame element 90. Furthermore, the air between the mold release film 30 and the frame 98 can be extracted through the gap by a vacuum pump, thus evacuating the space between the lower surface of the frame element 90 and the mold release film 30.

[0276] By evacuating the space between the lower surface of the frame element 90 and the mold release film 30 under reduced pressure and, if necessary, by supplying compressed air from line L2 into space S, the mold release film 30 can be stretched so that it is in close contact with the inner circumferential surface of the hole of the frame element 90 and with the lower surface of the frame 98.

[0277] In this device, by changing the thickness of the frame 98, which is to be inserted into the hole of the frame element 90, the depth for the adaptability can be changed, i.e., the distance between the lower surface of the frame material 90 (the surface with which the mold tool release film 30 is in contact) and the lower surface of the frame 98 (the surface on the side of the mold tool release film 30).

[0278] In the test, the mold release film 30 was first fixed to a clamping device 92 using a frame 98 with a depth of 0.8 mm to accommodate the mold's conformability, so that it was in close contact with the frame element 90. The mold release film 30 was positioned so that the surface of the side with the second thermoplastic resin layer faced upwards (towards the side of the frame element 90). Then, after heating the entire clamping device 92 to 180 °C with a heating plate 96, the air between the frame 98 and the mold release film 30 was extracted by operating the vacuum pump. Furthermore, compressed air (0.5 MPa) was supplied to chamber S from line L2, causing the mold release film 30 to conform to the frame element 90 and the frame 98.This condition was maintained for 3 minutes, and the vacuum level of the vacuum pump was checked. It was then visually confirmed whether the mold release film 30 had conformed to the corner (the corner formed by the inner circumferential surface of the hole in the frame element 90 and the lower surface of the frame 98). Afterward, the operation of the vacuum pump and the supply of compressed air were stopped, and the mold release film 30 was quickly removed. The removed mold release film 30 was visually inspected to confirm whether or not any separation between the layers was observed. The results were evaluated according to the following standards. ◯ (Good): The mold release film conformed completely to the mold and no separation between the layers was observed. Δ (Acceptable): The mold release film adapted to the mold, however, separation was observed between the layers of the mold release film. × (Bad): The mold release film could not adapt to the mold. (Waviness test)

[0279] The waviness of the mold release film was measured using the following method.

[0280] At 25 °C, a 10 cm × 10 cm square mold release film was left on a flat metal plate for 30 seconds. The maximum height (cm) of the section of the mold release film lifted from the metal plate was measured, and this measurement was used as the waviness. The results were evaluated according to the following standards. ◯ (Good): The waviness was less than 1 cm. × (Bad): The waviness was at least 1 cm. (Mold tool contamination)

[0281] An unmolded substrate was placed on the lower mold for injection molding in a 180°C environment. After vacuum adsorption of the mold release film onto the upper mold, the upper and lower molds were closed, and injection molding was performed at 7 MPa for 180 seconds using an epoxy resin for semiconductor molding. Injection into the mold was repeated 1000 times under the above conditions. The contamination of the mold at this time was visually inspected. The results were evaluated according to the following standards. ◯ (Good): No contamination of the mold was detected. × (Bad): Contamination of the mold was detected. [Example 1]

[0282] ETFE film (1-1) was used as the first thermoplastic resin layer and ETFE film (1-1) was used as the second thermoplastic resin layer.

[0283] Bondeip (trade name) PA100 main agent / Bondeip (trade name) PA100 curing agent / isopropanol / water were mixed in a mass ratio of 1 / 1 / 2 / 1.5 to obtain a composition 1 for the formation of an antistatic layer.

[0284] Composition 1 for the formation of an antistatic layer was applied at a coating quantity of 0.3 g / m². 2A coating of 0.5 g / m² was applied to a surface (the smooth surface) of the second thermoplastic resin layer and dried to form an antistatic layer. Then, an adhesive composition 1, obtained by mixing CRISVON NT-258 / Coronate 2096 / ethyl acetate in a mass ratio of 18 / 1 / 80, was applied to the surface of the antistatic layer. 2The adhesive layer was applied and dried to form an adhesion layer. The first thermoplastic resin layer was laminated onto the adhesion layer, so that the side with irregularities became the outside of the mold release film. Dry lamination was carried out under the condition that the stress applied to both the first and second thermoplastic resin layers was 8 N, producing a mold release film with the same structure as the mold release film 1 in the first embodiment. [Example 2]

[0285] A mold release film was produced in the same way as in Example 1, except that the first thermoplastic resin layer and the second thermoplastic resin layer were changed to the ETFE film (1-2). [Example 3]

[0286] A mold release film was produced in the same way as in Example 1, except that the first thermoplastic resin layer and the second thermoplastic resin layer were changed to the ETFE film (2-1). [Example 4]

[0287] A mold release film was produced in the same way as in Example 1, except that the second thermoplastic resin layer was changed to the PBT film (1-1) and the stress applied to the second thermoplastic resin layer at the time of dry lamination was changed from 8 N to 13 N. [Example 5]

[0288] A mold release film was produced in the same way as in Example 1, except that the second thermoplastic resin layer was changed to the polyamide film (1-1) and the stress applied to the second thermoplastic resin layer at the time of dry lamination was changed from 8 N to 9 N. [Example 6] (Reference example)

[0289] A mold release film was produced in the same way as in Example 4, except that the first thermoplastic resin layer was changed to the TPX film (1-1) and the stress applied to the first thermoplastic resin layer at the time of dry lamination was changed from 8 N to 9 N. [Example 7]

[0290] A mold release film was produced in the same way as in Example 1, except that the first thermoplastic resin layer was changed to the ETFE film (1-3) and the stress applied to the first thermoplastic resin layer at the time of dry lamination was changed to 3 N. [Example 8]

[0291] By adding a conductive polymer A to the adhesive composition 1, a composition 2 for forming an antistatic layer was produced. The amount of conductive polymer A added, calculated as solids content, was 30 wt% relative to the adhesive component. A mold release film was produced in the same way as in Example 1, except that composition 2 was used to form an antistatic layer instead of composition 1 and adhesive composition 1. [Example 9]

[0292] Pelestat NC6321 was dissolved in ethyl acetate to obtain 10 wt%, yielding composition 3 for the formation of an antistatic layer. A mold release film was prepared in the same manner as in Example 1, except that composition 3 was used instead of composition 1 for the formation of an antistatic layer. [Example 10]

[0293] The ETFE (3 parts of soot kneaded in) film (1-1) was used as such as a separating film. [Example 11]

[0294] A mold release film was produced in the same way as in Example 1, except that no composition 1 was used to form an antistatic layer. [Example 12]

[0295] A mold release film was produced in the same way as in Example 1, except that the second thermoplastic resin layer was changed to the PET film (1-2) and the stress applied to the second thermoplastic resin layer at the time of dry lamination was changed from 8 N to 26 N. [Example 13]

[0296] A mold release film was produced in the same way as in Example 1, except that the second thermoplastic resin layer was changed to the PET film (1-1) and the stress applied to the second thermoplastic resin layer at the time of dry lamination was changed from 8 N to 30 N.

[0297] Regarding the mold release films in Examples 1 to 13, the value of {(E1' × T1 × W1) × F2} / {(E2' × T2 × W2) × F1} at the time of dry lamination, the peel strength at 180 °C, the surface resistance of the antistatic layer, the modulus of elasticity (the storage modulus of elasticity E' (25) at 25 °C and the storage modulus of elasticity E' (180) at 180 °C) of each of the first thermoplastic resin layer and the second thermoplastic resin layer, and the results of the ash adhesion test, the 180 °C adaptation test, the waviness test, and the mold contamination test are shown in Tables 1 and 2. Table 1 Example. 1 2 3 4 5 6 Film structure First thermoplastic resin layer ETFE film (1-1) ETFE film (1-2) ETFE film (2-1) ETFE film (1-1) ETFE film (1-1) TPX film (1-1) Intermediate shift Composition for forming an adhesive layer Adhesive composition 1 Adhesive composition 1 Adhesive composition 1 Adhesive composition 1 Adhesive composition 1 Adhesive composition 1 Material for forming an antistatic layer Composition 1 for the formation of an antistatic layer Composition 1 for the formation of an antistatic layer Composition 1 for the formation of an antistatic layer Composition 1 for the formation of an antistatic layer Composition 1 for the formation of an antistatic layer Composition 1 for the formation of an antistatic layer Second thermoplastic adhesive layer ETFE film (1-1) ETFE film (1-2) ETFE film (2-1) PBT Film (1-1) Polyamide film (1-1) PBT Film (1-1) Voltage (N) applied to the first thermoplastic resin layer / the second thermoplastic resin layer 8 / 8 8 / 8 8 / 8 8 / 13 8 / 9 9 / 13 {(E1' × T1 x W1) × F2} / {(E2' × T2 x W2) × F1} 1,0 1,0 1,0 0,98 1,0 1,0 peel strength (N / cm) at 180°C 1,8 1,5 1,5 1,8 1,8 1,3 Surface resistance (Ω / ΔT) of the antistatic layer 1 × 10 9 1 × 10 9 1 × 10 9 1 × 10 9 1 × 10 9 1 × 10 9 Elastic modulus (MPa) of the first thermoplastic resin layer E' (25) 900 900 800 900 900 1200 E' (180) 40 40 10 40 40 30 Elastic modulus (MPa) of the second thermoplastic resin layer E' (25) 900 900 800 1800 1200 1800 E' (180) 40 40 10 120 280 120 Ash adhesion test ◯ ◯ ◯ ◯ ◯ ◯ 180 °C acclimatization test ◯ ◯ ◯ ◯ ◯ ◯ Ripple test ◯ (0 cm) ◯ (0 cm) ◯ (0 cm) ◯ (0.7 cm) ◯ (0.3 cm) ◯ (0.5 cm) Mold tool contamination ◯ ◯ ◯ ◯ ◯ ◯ Table 2 Example. 7 8 9 10 11 12 13 Film structure First thermoplastic resin layer ETFE film (1-3) ETFE film (1-1) ETFE film (1-1) ETFE (3 parts carbon black kneaded in) film (1-1) ETFE film (1-1) ETFE film (1-1) ETFE film (1-1) Intermediate shift Composition for forming an adhesive layer Adhesive composition 1 Composition 2 for the formation of an antistatic layer Adhesive composition 1 Adhesive composition 1 Adhesive composition 1 Adhesive composition 1 Material for forming an antistatic layer Composition 1 for the formation of an antistatic layer Composition 3 for the formation of an antistatic layer Composition 1 for the formation of an antistatic layer Composition 1 for the formation of an antistatic layer Second thermoplastic resin layer ETFE film (1-1) ETFE film (1-1) ETFE film (1-1) ETFE film (1-1) PET film (1-2) PET film (1-1) Voltage (N) applied to the first thermoplastic resin layer / the second thermoplastic resin layer 3 / 8 8 / 8 8 / 8 - 8 / 8 8 / 26 8 / 30 {(E1' × T1 x W1) × F2} / {(E2' × T2 × W2) × F1} 1,07 1,0 1,0 - 1,0 1,0 1,0 peel strength (N / cm) at 180°C 1,5 0,3 1,8 - 1,8 1,6 1,8 Surface resistance (Ω / Ω) of the antistatic layer 1 × 10 9 1 × 10 8 1 × 10 10 1 × 10 9 1 × 10 15 1 × 10 9 1 × 10 9 Table 2 (continued) Example. 7 8 9 10 11 12 13 Elastic modulus (MPa) of the first thermoplastic resin layer E' (25) 900 900 900 1500 900 900 900 E' (180) 40 40 40 120 40 40 40 Elastic modulus (MPa) of the second thermoplastic resin layer E' (25) 900 900 900 - 900 3000 4000 E' (180) 40 40 40 - 40 90 580 Ash adhesion test ◯ ◯ ◯ ◯ × ◯ ◯ 180 °C acclimatization test ◯ Δ ◯ ◯ ◯ ◯ × Ripple test o (0.8 cm) ◯ (0 cm) ◯ (0 cm) o (0 cm) ◯ (0 cm) × (1.3 cm) × (1.5 cm) Mold tool contamination ◯ ◯ ◯ × ◯ ◯ ◯

[0298] As demonstrated by the preceding results, the mold release films in Examples 1 to 9 showed no ash adhesion in the ash adhesion test and exhibited a lower probability of electrostatic charging. Furthermore, their results in the 180 °C acclimatization test, the waviness test, and the mold contamination test were also good. In contrast, mold contamination was detected in the mold release film in Example 10, to which carbon black had been added. Ash was deposited in the ash adhesion test on the mold release film in Example 11, where the intermediate layer did not contain a polymeric antistatic agent. The mold release film in Example 12, where the difference in storage modulus at 25 °C between the first thermoplastic resin layer and the second thermoplastic resin layer exceeded 1200 MPa, exhibited significant waviness.

[0299] In the case of the mold release film in Example 13, where the difference in storage modulus at 25 °C between the first thermoplastic resin layer and the second thermoplastic resin layer exceeded 1200 MPa and the elastic modulus at 180 °C of the second thermoplastic resin layer exceeded 300 MPa, the mold conformability was poor and the waviness was large. COMMERCIAL APPLICABILITY

[0300] The mold release film of the present invention is applicable in a variety of ways in the manufacture of semiconductor package modules, etc. REFERENCE MARK

[0301] 1: Mold release film, 2: First thermoplastic resin layer, 3: Second thermoplastic resin layer, 4: Intermediate layer, 10: Substrate, 12: Semiconductor chip (semiconductor element), 14: Resin encapsulation section, 14a: Top surface of resin encapsulation section 14, 16: Ink layer, 18: Bonding wire, 19: Cured product, 20: Fixed upper mold, 22: Lower cavity element, 24: Movable lower mold, 26: Cavity, 30: Mold release film, 40: Curable resin, 50: Upper mold, 52: Lower mold, 54: Cavity, 56: Cavity surface, 58: Substrate arrangement section, 60: Resin injection section, 62: Resin arrangement section, 64: Piston, 70: Substrate, 72: Semiconductor chip (Semiconductor element), 74: Underfill (resin encapsulation section), 80: Mesh, 82: Mesh, 84: Drain opening, 90: Frame material, 92: Clamping device, 92A: Upper element, 92B: Lower element, 94: Weight, 96: Heating plate, 98: Frame, S: Space, L1: Conduit, L2: Conduit110: Semiconductor package, 120: Semiconductor package,

Claims

[1] Mold release film, characterized by that he comprising a first thermoplastic resin layer, a second thermoplastic resin layer, and an intermediate layer arranged between the first thermoplastic resin layer and the second thermoplastic resin layer, wherein The first thermoplastic resin layer and the second thermoplastic resin layer each have a storage elasticity modulus at 180 °C of 10 to 300 MPa, wherein the difference in the storage elasticity modulus at 25 °C between these is at most 1200 MPa and their thicknesses are from 12 to 50 µm. the intermediate layer comprises a layer containing a polymeric antistatic agent, and the first thermoplastic resin layer comprises one or more thermoplastic polymers and all thermoplastic polymers included in the first thermoplastic resin layer are fluoroolefin polymers. [2] Mold release film according to claim 1, wherein the intermediate layer is an intermediate layer comprising a layer containing a polymeric antistatic agent and an adhesive layer comprising an adhesive that does not contain a polymeric antistatic agent, or an adhesive layer comprising a polymeric antistatic agent. [3] Mold release film according to claim 1 or 2, wherein both the first thermoplastic resin layer and the second thermoplastic resin layer do not contain an inorganic additive. [4] Mold release film according to any one of claims 1 to 3, wherein the peel strength between the first thermoplastic resin layer and the second thermoplastic resin layer, measured at 180 °C according to JIS K6854-2, is at least 0.3 N / cm. [5] Mold release film according to one of claims 1 to 4, wherein the surface resistance of the layer containing a polymeric antistatic agent is at most 10 10 Ω / □ is. [6] Mold release film according to any one of claims 1 to 5, wherein the waviness measured by the following measuring method is at most 1 cm: (Method for measuring waviness) At 20 to 25 °C, a square-shaped mold release film measuring 10 cm × 10 cm is left on a flat metal plate for 30 seconds, with the maximum height (cm) of the section of the mold release film lifted from the metal plate being measured. The measurement is taken and the measured value is used as the ripple. [7] Mold release film according to one of claims 1, 2 and 4 to 6, wherein the first thermoplastic resin layer comprises at least one selected from the group consisting of an inorganic additive and an organic additive, wherein the inorganic additive is selected from the group consisting of carbon black, silicon dioxide, titanium dioxide, cerium oxide, aluminum cobalt oxide, mica and zinc oxide, and the organic additive is selected from the group consisting of silicone oil and metal soap. [8] Method for manufacturing a semiconductor package comprising a semiconductor element and a resin encapsulation section formed from a curable resin for encapsulating the semiconductor element, characterized by , that it a step of arranging a mold release film, as defined in any one of claims 1 to 7, on a surface of a mold which is to be in contact with a curable resin, wherein the second thermoplastic resin layer is in contact with the mold, a step of arranging a substrate, which has a semiconductor element mounted on it, in the mold tool, and filling a space in the mold tool with a curable resin followed by curing to form a resin encapsulation section, thereby obtaining an encapsulated body which has the substrate, the semiconductor element and the resin encapsulation section, and includes a step of separating the encapsulated body from the mold. [9] Method for producing a semiconductor housing according to claim 8, wherein in the step of obtaining an encapsulated body a part of the semiconductor element is in direct contact with the separating film. [10] Method for producing a mold release film comprising a step of dry lamination of a first film to form a first thermoplastic resin layer and a second film to form a second thermoplastic resin layer using an adhesive, characterized by , that the storage elasticity modulus E1' (MPa), the thickness T1 (µm), the width W1 (mm) and the tensile force F1 (N) exerted on it at the dry lamination temperature t (°C) of one of the first and second films and the storage elasticity modulus E2' (MPa), the thickness T2 (µm), the width W2 (mm) and the tensile force F2 (N) exerted on it at the dry lamination temperature t (°C) of the other film satisfy the following formula (I), 0.8≤{(E1'×T1×W1)×F2} / {(E2'×T2×W2)×F1}≤1.2 (I) wherein the storage elastic modulus E1' (180) and E2' (180) at 180 °C is from 10 to 300 MPa, the difference in the storage elastic modulus at 25 °C, i.e. |E1' (25) - E2' (25)|, is at most 1200 MPa, and T1 and T2 are each from 12 to 50 (µm), and wherein the first thermoplastic resin layer comprises one or more thermoplastic polymers and all thermoplastic polymers included in the first thermoplastic resin layer are fluoroolefin polymers.

Images