KR20220143764A - Multilayer Release Film - Google Patents

Abstract

Provided is a multilayer release film having excellent physical properties, such as fracture resistance, followability, release property, side bite prevention, and cushion layer seeping suppression. The above object is to irradiate a multilayer film including a release layer (A) containing a non-crosslinkable resin and a radical scavenger and a resin layer (B) containing an ethylene-based polymer, and the resin layer (B) is crosslinked, It is the multilayer release film formed, and the contact angle with respect to the water of the release layer (A) after electron beam irradiation is 90 degrees - 130 degrees, It is solved by the multilayer release film.

Description

Multilayer Release Film

The present invention relates to a multilayer release film excellent in physical properties such as break resistance, followability, release property, side bite prevention, cushion layer seeping suppression, etc. More specifically, it is widely used in a printed wiring board manufacturing process or a resin sealing process of a semiconductor It relates to a possible multilayer release film, a method for its preparation and its use.

As a release film used in a printed wiring board manufacturing process with improved moldability and followability, a multilayer film having a central layer crosslinked with radiation such as an electron beam and a release layer (surface layer) that is not crosslinked with radiation such as an electron beam is disclosed. There is (Patent Document 1).

However, it has been pointed out that the release film is broken when resin-sealing articles such as semiconductor chips by the compression molding method or when pressing a flexible printed circuit board (hereinafter also referred to as 'FPC') with a coverlay.

Japanese Patent Laid-Open No. 2012-179827

In view of the limitations of the prior art, the present invention provides a process for resin-sealing articles such as semiconductor chips by compression molding or transfer molding, preferably, a process for attaching a coverlay for FPC, a molded article after sealing with a semiconductor resin, In the case of FPC pressing, in the former case, a multilayer release film that can be easily released without causing film breakage, insufficient resin, or side gripping, and in the latter, film breakage, adhesive exudation, and exudation of the cushion layer. An object of the present invention is to provide a multilayer release film that can be easily released without causing the film to be molded.

As a result of repeated intensive studies to solve the above problems, the present inventors found that the breakage is due to deterioration of the non-crosslinkable resin constituting the surface release layer by electron beam irradiation, and a more suitable radical scavenger is contained in the release layer By doing this, it discovered that the said deterioration could be prevented, and came to complete this invention.

That is, the present invention

[1] A multilayer film comprising a release layer (A) containing a non-crosslinkable resin and a radical scavenger, and a resin layer (B) containing an ethylene-based polymer;

A multilayer release film in which the resin layer (B) is crosslinked by electron beam irradiation,

The contact angle to water of the release layer (A) after electron beam irradiation is 90° to 130°, the multilayer release film.

[2] The multilayer release film according to [1], wherein the release layer (A) has a melting point of 200°C or higher as determined by differential scanning calorimetry.

[3] The multilayer mold release described in [1] or [2], wherein the resin contained in the mold release layer (A) is at least one selected from the group consisting of α-olefin polymers, polyesters, fluorine-based resins, and polystyrene-based resins. film.

[4] The multilayer release film according to any one of [1] to [3], wherein the total content of the radical scavenger is 0.5 to 2.0 wt% based on the total weight of the release layer (A).

[5] The multilayer according to any one of [1] to [4], wherein the radical scavenger is selected from the group consisting of hindered amine light stabilizers, phenolic antioxidants, phosphorus antioxidants, polymerization inhibitors, and mixtures thereof. release film.

[6] The multilayer release film according to any one of [1] to [5], wherein the radical scavenger contained in the release layer (A) includes a hindered amine light stabilizer.

[7] The multilayer release film according to any one of [1] to [5], wherein the radical scavenger contained in the release layer (A) contains a phenolic antioxidant.

[8] The multilayer release film according to any one of [1] to [5], wherein the radical scavenger contained in the release layer (A) includes a hindered amine light stabilizer and a phosphorus antioxidant.

[9] The multilayer according to any one of [3] to [8], wherein the α-olefin polymer contained in the release layer (A) is poly(4-methyl-1-pentene) and/or a copolymer thereof. release film.

[10] The multilayer release film according to any one of [3] to [8], wherein the polyester contained in the release layer (A) is polybutylene terephthalate.

[11] The multilayer release film according to any one of [1] to [10], having the release layer (A) in both surface layers and the resin layer (B) in the core layer.

[12] The multilayer release film according to any one of [1] to [11], which is used in a printed wiring board manufacturing process or a semiconductor resin encapsulation process.

[13] A multilayer film comprising a release layer (A) containing a radical scavenger and a non-crosslinkable resin, and a resin layer (B) containing an ethylene-based polymer.

[14] A multilayer release film in which the resin layer (B) is crosslinked by electron beam irradiation of the multilayer film of [13],

The contact angle to water of the release layer (A) after electron beam irradiation is 90° to 130°, the multilayer release film.

The multilayer release film of the present invention can suppress breakage of the film during sealing or pressing without impairing the followability and releasability during sealing or pressing, and has high practical value.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows an example of the resin encapsulation process of the semiconductor chip using the multilayer release film of this invention.
It is a schematic diagram which shows the test method, such as the peeling state after shaping|molding, in the Example/comparative example of this invention.
It is a schematic diagram explaining the test method, such as the peeling state after adhesion, in the Example/comparative example of this invention.

(Multilayer Release Film)

In the present invention, a multilayer film including a release layer (A) containing a non-crosslinkable resin and a radical scavenger and a resin layer (B) containing an ethylene-based polymer is irradiated with electron beams to crosslink the resin layer (B) It is a multilayer release film formed as a multilayer release film whose contact angle with respect to the water of the release layer (A) after electron beam irradiation is 90 degrees - 130 degrees.

The multilayer release film of this invention is a laminated|multilayer film containing the mold release layer (A) which has releasability with respect to a molded article or a metal mold|die, and the resin layer (B) formed by electron beam crosslinking. Another aspect of this invention is a laminated|multilayer film which has a mold release layer (A) in both surface layers, and has a resin layer (B) formed by electron beam crosslinking in a core layer. Another aspect of this invention is a laminated|multilayer film which has a mold release layer (A) in both surface layers, has a resin layer (B) formed by electron beam crosslinking in a core layer, and has an intermediate|middle layer as needed on both sides of a core layer.

(Release layer (A))

The contact angle of the release layer (A) with respect to water after electron beam irradiation is 90° to 130°, and by having such a contact angle, the release layer (A) has low wettability, and does not adhere to the cured sealing resin or FPC , the mold surface, The molded article can be easily released.

The contact angle of the release layer (A) with respect to water is preferably 95° to 120°, more preferably 98° to 115°, and still more preferably 100° to 110°.

The contact angle with respect to the water of the film surface may be measured by a conventional method in the art, for example, it can be measured by the method described in the Examples of the present application.

In the present invention, the non-crosslinkable resin contained in the release layer (A) means that the elongation at break at room temperature measured by the following method is compared with the elongation at break before electron beam irradiation, and the absorbed dose of 100 kGy at an acceleration voltage of 200 kV It is a resin which falls to 20% or less after irradiation with an electron beam, and alpha olefin polymer, polyester, a fluorine-type resin, and a polystyrene-type resin are mentioned. Non-crosslinkable resin may be used individually by 1 type, and may use 2 or more types together.

(Elongation at break)

A film having a width of 15 mm is prepared, the distance between the initial chucks is 50 mm, and the elongation at 300 mm/min is made under a 23°C environment, and the elongation when the film is fractured is the elongation at break.

(electron beam irradiation)

The film sample was irradiated with an electron beam at an accelerating voltage of 200 kV and an absorbed dose of 100 kGy.

Carbon number of the alpha olefin polymer which can be used for a mold release layer (A) is 3 or more, Preferably it is 6 or more. α olefin polymers include polymers of (4-methyl-1-pentene), octene, decene, or copolymers with other olefin units. Among them, a polymer or copolymer of (4-methyl-1-pentene) is preferable.

The fluororesin usable for the release layer (A) may be a resin containing structural units derived from tetrafluoroethylene. It may be a homopolymer of tetrafluoroethylene, but may also be a copolymer with other olefins. Examples of other olefins include ethylene. A copolymer containing tetrafluoroethylene and ethylene as monomer structural units is a preferred example, and in this copolymer, the molar ratio (TFE/E) of the tetrafluoroethylene-based unit to the ethylene-based unit is 80/ It is preferable that it is 20-40/60.

Polybutylene terephthalate or polyethylene terephthalate is mentioned as polyester which can be used for a mold release layer (A).

The polystyrene-based resin that can be used for the release layer (A) contains styrene homopolymer and copolymer, and the structural unit derived from styrene contained in the polymer is preferably at least 60% by weight or more, more preferably 80 more than % by weight.

The polystyrene-based resin may be isotactic polystyrene or syndiotactic polystyrene, but isotactic polystyrene is preferable from the viewpoint of transparency and availability, and syndiotactic polystyrene is preferable from the viewpoint of releasability and heat resistance. do. Polystyrene may be used individually by 1 type, and may use 2 or more types together.

The release layer (A) of this invention contains a radical scavenger. Preferably, the release layer (A) contains 0.5 to 2.5 wt%, more preferably 0.5 to 2.0 wt% of the radical scavenger relative to the total weight of the release layer (A).

When the resin layer (B) of the release film is irradiated with electron beam, the surface-side release layer is also inevitably irradiated, but non-crosslinkable resins such as polymers of α-olefin including (4-methyl-1-pentene) are structurally It is easy to be decomposed by an electron beam. By including the radical scavenger in the above range, it is possible to suppress the degradation by trapping the radicals generated by electron beam irradiation.

The radical scavenger in the present invention is selected from the group consisting of hindered amine light stabilizers (hereinafter also referred to as HALS), phenolic antioxidants, phosphorus antioxidants, polymerization inhibitors, and mixtures thereof.

More preferably, the radical scavenger is a hindered amine light stabilizer or a phenolic antioxidant. Moreover, the combination of a hindered amine light stabilizer and a phosphorus antioxidant is also preferable at the point which can maintain the elongation at break.

Examples of the hindered amine light stabilizer (HALS) include a hindered amine light stabilizer having an N-H bond, a hindered amine light stabilizer having an N-R bond (R represents a monovalent hydrocarbon group), and an N-OR bond (R is a monovalent hydrocarbon group) and hindered amine light stabilizers.

As hindered amine light stabilizers having an N-H bond, tetrakis(2,2,6,6-tetramethyl-4-piperidyl)butane-1,2,3,4-tetracarboxylate and bis-tetramethyl -4-piperidyl) sebacate, which can be obtained from ADEKA under the product name Adeka Stub LA-57 and the product name Adeka Stub LA-77, respectively. The latter is Tinuvin 770, available from BASF Japan Corporation.

Examples of the hindered amine light stabilizer having an N-R bond (R represents a monovalent hydrocarbon group) include a hydrocarbon group having 1 to 10 carbon atoms as R, and among these, it is preferable that R is a methyl group. Such HALS include tetrakis(1,2,2,6,6-tetramethyl-4-piperidyl)butane-1,2,3,4-tetracarboxylate and bis(1,2,2,2 -4-piperidyl) sebacate, which can be obtained from ADEKA as a product name ADEKA stub LA-52 and a product name ADEKA stub LA-72, respectively.

Examples of the hindered amine light stabilizer having an N-OR bond (R represents a monovalent hydrocarbon group) include a hydrocarbon group having 1 to 10 carbon atoms. Such HALS include bis(1-undecanoxy-2,2,6,6-tetramethylpiperidin-4-yl)carbonate, bis-(1-octyloxy-2,2,6,6-tetra methyl-4-piperidyl) sebacate, the former being available from ADEKA under the product name ADEKA Stub LA-81, and the latter being available from BASF Japan Corporation under the product name Tinuvin123.

As phenolic antioxidants, octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate (product name Irganox1076, BASF Japan Corporation), 2,6-di-tertbutyl-4 -Methylphenol (product name H-BHT, Honshu Chemical Industry Co., Ltd.) is mentioned.

Examples of the phosphorus antioxidant include tris(2,4-di-tert.-butylphenyl)phosphite (product name Irgafos 168, BASF Japan Corporation).

As a polymerization inhibitor, metoquinone, hydroquinone, phenothiazine, etc. are mentioned.

It is preferable that the mold release layer (A) has constant heat resistance at the temperature of the mold at the time of molding (typically 120 to 180° C.) or the temperature at the time of pressing the FPC (typically 150 to 190° C.).

From such a viewpoint, it is preferable that melting|fusing point of a mold release layer (A) is 200 degreeC or more. Although there is no upper limit in particular in melting|fusing point, Usually, melting|fusing point of a commercially available crystalline resin is 280 degrees C or less in many cases.

(resin layer (B))

The resin layer (B) in this invention contains an ethylene-type polymer, and forms a crosslinked structure by electron beam irradiation. Although cushioning property can be provided by an ethylene-type copolymer, when pressure is applied while heating at high temperature, the exudation by melting of a cushion layer will generate|occur|produce. Therefore, oozing can be suppressed, maintaining cushioning property by performing electron beam bridge|crosslinking.

From the viewpoint of followability of the release film to a printed wiring board or semiconductor package and extensibility at the time of pressing, polyethylene, ethylene-α-olefin copolymer, ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid ester copolymer as ethylene-based polymers a copolymer, an ethylene-ethyl acrylate copolymer, and an ethylene-cycloolefin copolymer.

(Other floors)

The multilayer release film of this aspect may have layers other than a mold release layer (A) and a resin layer (B), unless it is contrary to the objective of this invention. For example, you may have an intermediate|middle layer between the mold release layer (A) as both surface layers, and the resin layer (B) as a core layer as needed. The material used for the intermediate layer is not particularly limited as long as it can firmly bond the release layer (A) and the resin layer (B) and does not peel even in the resin encapsulation step, release step, or press step of FPC.

For example, when the release layer (A) comprises a 4-methyl-1-pentene copolymer, the intermediate layer comprises polypropylene, a propylene-ethylene copolymer, a mixture of polypropylene and polyethylene, 4-methyl-1-pentene and The mixture of polyethylene, an ethylene copolymer, the mixture of a mold release layer and a core layer, methylpentene, and (alpha)-olefin copolymer may also be included.

Although the thickness of an intermediate|middle layer will not have a restriction|limiting in particular as long as the adhesiveness of a mold release layer (A) and a resin layer (B) can be improved, For example, it is 0.5-10 micrometers.

Although there is no restriction|limiting in particular in the total thickness of the multilayer release film of this invention, For example, it is preferable that it is 10-300 micrometers, It is more preferable that it is 30-150 micrometers, It is most preferable that it is 50-120 micrometers. When the total thickness of a multilayer release film exists in the said range, while the handleability at the time of using it as a roll is favorable, since there is little waste amount of a film, it is preferable.

(Manufacturing method of multilayer release film)

The multilayer release film of this invention can be manufactured by arbitrary methods.

The multilayer film before crosslinking is, for example, 1) a method of manufacturing a multilayer film by co-extrusion molding and laminating a release layer (A) and a resin layer (B), 2) a resin layer (B) On the film to be used, the molten resin of the resin serving as the release layer (A) or the intermediate layer is applied and dried, or the resin solution obtained by dissolving the resin serving as the release layer (A) or the intermediate layer in a solvent is applied and dried. , a method for producing a release film (application method), 3) a film serving as the release layer (A) and a film serving as the resin layer (B) are prepared in advance, and by laminating (laminate) these films, a multilayer film The manufacturing method (laminate method), etc. are employable. And the multilayer release film of this invention is obtained by irradiating the obtained multilayer film with electron beam and bridge|crosslinking a resin layer (B).

(resin sealing process)

The multilayer release film of this invention is used for the resin sealing process by the compression molding method or the transfer molding method, for example. The multilayer release film of the present invention can be used by arranging a semiconductor chip or the like in a mold to inject and mold a resin between the semiconductor chip and the like and the inner surface of the mold. By using the multilayer release film of the present invention, it is possible to effectively prevent peeling defects from the mold, generation of burrs, and the like.

The resin used in the manufacturing process by the compression molding method may be any of a thermoplastic resin and a thermosetting resin, but a thermosetting resin is widely used in the art, and it is particularly preferable to use an epoxy-based thermosetting resin.

As for the resin used in the manufacturing process by the said transfer molding method, a thermosetting resin is widely used in the industry, and it is preferable to use especially an epoxy thermosetting resin.

For the resin encapsulation process using the multilayer release film of the present invention, those conventionally known in the art can be appropriately employed, and there is no particular limitation. For example, in the case of a resin encapsulation process of a semiconductor chip by a compression molding method, 1. to 9, shown in 1. A process in which each step is performed in this order is preferred.

More specifically, first, '1. In the 'film cut' process, the multilayer release film 11 of the present invention is taken out from the roll-shaped roll, spread on the X-Y stage 13, and cut to a predetermined size. The predetermined size of the multilayer release film 11 is not particularly limited, but a clamper that covers the entire surface of the cavity 19c installed in the lower mold 19 used in the resin sealing process and constitutes the lower mold 19 . (19b) and the upper mold 15, it is preferable to have a size including a fixing bar for fixing the film 11 therebetween.

Next, in the '2. Frame-type installation' process, a frame 14 having a shape substantially overlapping with the fixing table is deployed on the XY stage 13, and the multilayer release film 11 cut to a predetermined size ), and installed so as to approximately overlap the fixture.

Next, '3. In the 'resin metering' step, a predetermined amount of the sealing resin 18 is weighed and placed in the frame 14 on the multilayer release film 11 . Although there is no restriction|limiting in particular in the quantity of the sealing resin 18, The '8. It is preferably approximately equal to the volume of the cavity 19c after the 'compression' process.

Next, '4. In the process of 'transferring resin + film', with the multilayer release film 11 adsorbed to the frame 14, together with the sealing resin 18 disposed on the release film 11, the X-Y stage 13 It is separated and conveyed, and placed on the lower mold 19 for performing resin sealing. At this time, the multilayer release film 11 covers the cavity 19c installed in the lower mold 19 , and the sealing resin 18 disposed on the multilayer release film 11 is positioned on the cavity 19c. , it is preferable to place

Next, '5. In the 'vacuum adsorption' process, a cavity in the lower mold 19 is held while the fixing base of the multilayer release film 11 is fixed between the frame 14 and the clampers 19b constituting the lower mold 19. By degassing from the adsorption port provided in (19c), the said multilayer release film 11 is adsorbed and supported along the inner surface of the cavity 19c. At this time, you may fix by adsorb|sucking the fixing base of the said release 11 film for the said process to the adsorption|suction port provided in the peripheral part of the lower die 19.

By being sucked and supported along the inner surface of the cavity 19c with the fixing bar at the periphery of the film fixed, the multilayer release film is elongated by a length approximately corresponding to the depth of the cavity. The (initial) depth of the cavity 19c in this process can be suitably set according to the thickness of the resin-sealing semiconductor element produced by the resin-sealing process of this embodiment. Although the (initial) depth of the cavity 19c in this process is 1.0-10.0 mm normally, it is not limited to this.

In this step, it is preferable that the multilayer release film 11 has the flexibility to be easily adsorbed and supported along the inner surface of the cavity 19c and has heat resistance to withstand the heating temperature of the molds 15 and 19 . Moreover, it is preferable that it can release|release easily from the metal mold|die 19 after resin sealing, and can peel easily from the sealing resin 18. FIG.

Next, '6. In the 'substrate installation' process, the substrate 16 on which the semiconductor chip 17 (and, if necessary, circuit components) is mounted is adsorbed to the upper mold 15 so that the semiconductor chip 17 faces down, and the semiconductor chip ( 17) is aligned by moving the upper mold 15 so that it is located approximately at the center of the cavity 19c of the lower mold 19.

Next, in the '7. mold clamping' process, while maintaining the space of the original cavity 19c (the cavity block 19a in the lower mold 19 is in its original position), the upper mold 15 and the lower mold (19) is contacted to perform mold clamping.

Next, '8. In the 'compression' process, the cavity block 19a is raised and the sealing resin 18 in the cavity 19c is compression-molded. As a result, the semiconductor chip 17 (and circuit components as necessary) on the substrate 16 is sealed with the sealing resin 18 .

The difference between the initial depth of the cavity 19c and the final depth of the cavity 19c after compression molding is preferably 1.0 mm or more, more preferably 1.3 mm or more, and particularly preferably 1.6 mm or more. In the case of resin-sealing a thick semiconductor chip 17 such as a large-capacity NAND-type flash memory, the difference between the initial depth of the cavity 19c and the final depth of the cavity 19c after compression molding tends to become large, and this Even in this case, the multilayer release film of the present invention can properly resin-seal the semiconductor chip 17 having a large thickness while effectively suppressing problems such as poor peeling.

Moreover, it is preferable that it is 0.5 mm or more, as for the final depth (resin thickness after compression molding) of the cavity 19c, it is more preferable that it is 0.7 mm or more, It is especially preferable that it is 1.0 mm or more. Since the final depth of the cavity 19c is 0.5 mm or more, it is possible to appropriately resin-seal the thick semiconductor chip 17 such as a large-capacity NAND-type flash memory.

In compression molding, it is preferable to heat to a temperature at which the sealing resin 18 exhibits suitable fluidity, and in the case where the sealing resin 18 is a thermosetting resin, heating is performed at a temperature and time at which the sealing resin after molding is sufficiently cured. it is preferable For example, in a resin encapsulation process, the maximum temperature can be set to 110-190 degreeC, and it is more preferable to set to 120-180 degreeC.

There is no particular limitation on the molding pressure and curing time at that time, either, and suitable conditions may be set according to the type of the sealing resin 18 and the sealing temperature. For example, a molding pressure of 50 to 300 kN, more preferably 70 -150 kN, hardening time 1 to 60 minutes, More preferably, it can set suitably in the range of 2 to 10 minutes.

As the sealing resin 18, as a liquid resin, solid resin at normal temperature may be sufficient, However, A sealing material, such as a liquid resin by heating at the time of resin sealing, can be employ|adopted suitably. As the sealing resin material, specifically, mainly an epoxy resin (a thermosetting resin that can be cured by forming a crosslinked network with epoxy groups remaining in the polymer, preferably a biphenyl type epoxy resin, bisphenol epoxy resin, o-cresol furnace A rock-type epoxy resin, etc.) is used, and as a sealing resin other than an epoxy resin, a polyimide resin (a polymer resin having an imide bond in the repeating unit of the main chain, preferably a bismaleimide type), a silicone resin ( A polymer resin having a siloxane bond in the repeating unit of the main skeleton, preferably a thermosetting addition type, etc.) commonly used as a sealing resin can be suitably used.

Next, in the '9. Mold Opening (Removing)' process, the upper mold 15 is separated from the lower mold 19, and the molded product (resin-encapsulated semiconductor chip) is taken out of the mold. At this time, it is preferable that the molded article peels easily from the multilayer release film 11, and in particular, it is preferable that the multilayer release film 11 on the side of the cavity 19c peels without biting the molded article. Moreover, it is preferable that the surface of the molded article after peeling has a favorable external appearance without a resin defect etc. The use of the multilayer release film of the present invention facilitates realization of such desirable results.

(Use of the multilayer release film in the FPC coverlay attaching process)

The multilayer release film of the present invention is provided in a step of laminating a circuit substrate having a metal wiring pattern formed thereon and a coverlay film constituting a printed wiring board by heating and pressing, between the coverlay film and a hot plate for heating and pressing. Can be placed and used. By using the multilayer release film of the present invention, it is possible to effectively prevent a defect in release from a hot plate or the like, protrusion of the adhesive on the coverlay film, and the like.

The adhesive on the coverlay film may be any of a thermoplastic resin and a thermosetting resin, but a thermosetting resin is widely used in the technical field, and it is particularly preferable to use an epoxy-based thermosetting resin.

The manufacturing process is the most representative, but not limited to, a process for integrating a circuit board for FPC and a coverlay film, and the multilayer release film of the present invention can also be applied to a manufacturing process other than a flexible printed wiring board.

<Example>

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited thereto.

In the following Examples/Comparative Examples/Preparation Examples, evaluation of physical properties/characteristics was performed by the following method.

(contact angle for water (water contact angle))

Based on JIS R3257, the water contact angle of the surface of the mold release layer (A) after electron beam irradiation was measured using a contact angle measuring device (the KYOWA INTER FACE SCIENCE company make, FACECA-W).

(Elongation at break)

Using the single-layer release film produced in Production Example, 50 mm between the initial chucks, and elongated in the TD direction at 300 mm/min in an environment of 23° C., the elongation at break of the film was measured as the elongation at break. . The measurement direction was made into the TD direction (the width direction at the time of film manufacture).

In the evaluation, the value of the elongation at break after irradiation with an absorption dose of 100 kGy at an acceleration voltage of 200 kV compared with the value of elongation at break after irradiation with electron beams is more than 20%, '○' when it is 20% or less It was evaluated as 'x'.

(Releasability: semiconductor resin encapsulation)

The resin encapsulation of the semiconductor chip was performed by the process as shown in FIG. 1 using the multilayer release film produced in each Example/Comparative example.

As the sealing resin, a sealing material for an epoxy lead frame package manufactured by Hitachi Chemical Industry Co., Ltd. (brand: CEL-9750 ZHF10) was used.

In the process of FIG. 1, '4. Resin + Film Transfer', '5. 'Vacuum adsorption', and 'Type 7 fastening' and '9. The detailed conditions of 'compression' are shown in FIGS. 2 (a), (b), and (c). In Fig. 2(a), the depth a1 of the cavity 29c at the initial stage of clamping is 2.4 mm, in Fig. 2(b), the width of the cavity 29c is 54 mm, in Fig. 2(b), the cavity The length in the vertical direction of the paper plane of 29c was 221 mm, and the final cavity depth (a2) after clamping and compression in FIG. 2C was 0.8 mm. The temperature (molding temperature) of the molding die was 175°C, the molding pressure was 96 kN, and the molding time was 120 seconds.

Then, as shown in "9. Mold opening (release)" in FIG. 1, the upper metal mold|die was pulled up, and the resin-sealed semiconductor chip (semiconductor package) was released from the release film. The following criteria evaluated the releasability of a release film.

(double-circle): The release film is peeled off naturally as soon as the mold is opened.

○: The release film is not peeled off naturally, but is easily peeled off by pulling it by hand (when tension is applied).

x: A release film is closely_contact|adhered to the resin sealing surface of a semiconductor package, and it cannot peel by hand.

(Releasability: FPC Coverlay Attachment)

Using the device of the configuration shown in Fig. 3, the coverlay films 76 are arranged on both sides of the circuit substrate 75, and the release films 71a or 72b and the glass cloth 78a or 78b are arranged on both sides thereof in this order. By using a hot plate (77a or 77b), temperature: 180 ° C., pressure: 10 MPa, heat press time: 130 seconds (preload: 10 seconds, main pressure: 120 seconds) to perform adhesion by heating and pressing, A printed board was fabricated.

1) The circuit substrate 75 uses a polyimide film having a thickness of 25 μm as a flexible resin substrate, in which copper wiring having a thickness of 22 μm (copper: 12 μm, plating: 10 μm) as a metal wiring pattern is formed, and the line of the copper wiring part The width/space width was 40 μm and 60 μm, respectively.

2) As the coverlay film 76, a polyimide film having a thickness of 12.5 µm as a flexible resin substrate, in which an adhesive layer having a thickness of 25 µm was formed, was used (manufactured by Nikan Kogyo Co., Ltd., trade name: CISV1225DB).

A plurality of portions (opening portions) corresponding to the terminal portions of the circuit substrate 75 were punched out in the coverlay film 76 . The size of the opening of the coverlay film 76 is 4 mm x 7 mm.

3) In the overlapping of the circuit base material 75 and the coverlay film 76, the former copper wiring and the latter adhesive layer are arrange|positioned so that they may oppose, In the overlapping of the coverlay film 76 and the release film 71a, , It has arrange|positioned so that the former polyimide film layer and the latter mold release layer may oppose.

The release film was peeled immediately after heat-pressing, and the following references|standards evaluated the releasability of the release film.

○: Easily peelable from a flexible printed circuit board.

x: It adheres to a flexible printed circuit board, and peeling cannot be carried out easily.

(Fracture of the release layer: semiconductor resin encapsulation)

The following criteria evaluated the fracture|rupture property of the release film at the time of performing release in the said process.

(circle): No film tear after releasing a release film from a semiconductor package after resin sealing.

x: After releasing the mold release film from the semiconductor package after resin sealing, the film is torn.

(Fracture of release layer: pasting FPC coverlay)

The following criteria evaluated the fracture|rupture property of the release film at the time of releasing at the said process.

(circle): After releasing the release film from FPC after heat-pressing, there is no film tearing.

x: After releasing a mold release film from FPC after heat-pressing, a film tearing.

(Mold followability: semiconductor resin encapsulation)

The following references|standards evaluated the mold followability of the mold release film at the time of releasing in the said process.

○: There is no shortage of resin (parts not filled with resin) in the semiconductor package at all, or there is a slight shortage of resin at the edge of the semiconductor package.

x: There are many resin vacancies in the edge part of a semiconductor package. Or film breakage occurs during molding.

(Followability (adhesive seepage suppression): FPC coverlay pasting)

With the same device and film combination as in the above evaluation of releasability, the amount of outflow of the adhesive on the copper wiring of the FPC after heating and pressing was observed with an optical microscope (manufactured by Kyencece, VHX-5000). evaluated.

○: The outflow to the opening is less than 25 μm.

×: The outflow to the opening exceeds 25 μm.

(Side bite: semiconductor resin sealing)

The following criteria evaluated the peeling defect by the side bite of the release film at the time of performing release in the said process.

(double-circle) : There is no bite mark and there is no peeling defect on the side of a semiconductor package.

(circle): There is a bite mark on the side of a semiconductor package, but there is no peeling defect.

x: There is a bite mark on the side of a semiconductor package, and peeling defect also generate|occur|produced.

(Cushion layer seeps out: paste FPC coverlay)

After heat-pressing with the same device and combination of films as in the evaluation of the release properties described above, the exudation of the cushion layer in the release film was evaluated according to the degree of adhesion of the release films 78a and 78b.

(circle): It is judged that the release films 78a, 78b can peel easily and the exudation of a cushion layer is small.

x: Since the release films 78a, 78b cannot be peeled easily, it is judged that the exudation of a cushion layer is large.

<Production Examples 1 to 16: Evaluation of a single-layer 50 μm thick film (release layer)>

(Unveiling)

Mitsui Chemicals Co., Ltd. 4-methyl-1-pentene copolymer resin (product name: TPX, brand name: DX818, melting point: 232??) 95 wt%, additive (radical scavenger) at a composition ratio of 5 wt%, a master batch was prepared. The kind of the used additive (radical scavenger) is as showing in the prescription of <Table 1>, the column of an additive, The detail of an additive is as follows.

- (Tinuvin770) Hindered Amine Light Stabilizer (HALS)

Bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate (product name: Tinuvin770DF) manufactured by BASF Japan Co., Ltd.

- (Tinuvin123) Hindered Amine Light Stabilizer (HALS)

Bis-(1-octyloxy-2,2,6,6-tetramethyl-4 piperidinyl) sebacate manufactured by BASF Japan Co., Ltd. (Product name: Tinuvin123)

- (LA-52) hindered amine light stabilizer (HALS)

Tetrakis (1,2,2,6,6-tetramethyl-4-piperidyl)butane-1,2,3,4-tetracarboxylate e (product name: Adecastab LA-52) manufactured by ADEKA )

- (LA-57): hindered amine light stabilizer (HALS)

Tetrakis (2,2,6,6-tetramethyl-4-piperidyl)butane-1,2,3,4-tetracarboxylate manufactured by ADEKA (Product name: Adecastab LA-57)

- (BHT) phenolic antioxidant

Honshu Chemical Industry Co., Ltd. 2,6-di-tert-butyl-4-methylphenol (product name: H-BHT)

- (Irganox 1076) phenolic antioxidant

Octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate (product name Irganox1076) manufactured by BASF Japan Co., Ltd.

- (Irgafos 168) Phosphorus-Based Antioxidant

Tris(2,4-di-tert.-butylphenyl)phosphite (product name Irgafos168) manufactured by BASF Japan Co., Ltd.

Next, after mixing so as to obtain the formulation shown in Table 1, the obtained resin composition was melt-extruded at a temperature of 270°C, and a slit width of a T-die was adjusted to form an unstretched film having a thickness of 50 μm.

(electron beam irradiation)

The obtained single-layer 50 μm thick film was irradiated with an electron beam at an absorption dose of 100 kGy at an accelerating voltage of 200 kV by an electron beam irradiation device. Table 1 shows the evaluation results.

<Table 1> Evaluation result of single-layer film

The elongation at break of the single-layer resin film (Production Example 16) not containing a radical scavenger (additive) was 553%, but the elongation at break of the film after electron beam irradiation was reduced to 5% (Preparation Example 11), and electron beam irradiation The elongation at break after the irradiation was lowered to less than 1% compared to before irradiation.

In the single-layer resin films of Preparation Examples 1 to 10 containing 0.5 to 2.0 wt% of a radical scavenger (additive) based on the total amount of the single-layer resin film, the value of elongation at break was compared with the value of elongation at break before electron beam irradiation. greater than 20%, and good elongation at break was maintained.

<Examples 1 to 8, Comparative Examples 1-2: Evaluation of the multilayer film>

(Unveiling)

The resin composition mixed in the composition ratio of said Table 1 was used as resin for mold release layers.

A low-density polyethylene resin (Mitsui-E DuPont Polychemical Co., Ltd. make, Miraton F9673P) was used as the resin for the core layer.

40 parts by mass of 4-methyl-1-pentene copolymer resin (manufactured by Mitsui Chemicals Co., Ltd., product name: TPX, brand name: DX818), and 60 parts by mass of low-density polyethylene resin (Mitsui E DuPont Polychemical Co., Ltd., Miraton F9673P) A resin composition was prepared by mixing, and used as an intermediate layer resin.

Three extruders (each 40 mm?) were prepared, the resin for the mold release layer described above was supplied to the first extruder, and the resin was melted at a temperature of 270°C. The resin for a core layer was supplied to the 2nd extruder, and it melt|melted at the temperature of 210 degreeC. The resin for a core layer was supplied to the 3rd extruder, and it melt|melted at the temperature of 270 degreeC.

The molten resin was guided to a distribution adapter, and through a T-die temperature set at 270°C, a five-layer film having a layer structure consisting of a release layer/intermediate layer/core layer/intermediate layer/release layer was obtained.

The obtained 5-layer coextrusion film had a total thickness of 50 µm for semiconductor resin encapsulation, and a total thickness of 120 µm for FPC coverlay attachment, and the layer structure was shown in Tables 2 and 3.

(electron beam irradiation)

The obtained multilayer film was irradiated with an electron beam at an accelerating voltage of 200 kV at the absorbed doses shown in Tables 2 and 3. The evaluation results are shown in Tables 2 and 3.

<Table 2> Evaluation result of multilayer film for semiconductor resin encapsulation

<Table 3> Evaluation result of multilayer film for FPC coverlay attachment

The multilayer films for semiconductor resin encapsulation of Examples 1 to 4 using a resin composition containing a radical scavenger (additive) in the release layer had good results in all evaluation items of breakage of the release layer, bite of the side, mold followability, and releasability. was obtained, but in Comparative Example 1 using a resin composition containing no radical scavenger (additive) for the release layer, the breakage of the release layer could not be suppressed.

Similarly, the multilayer films for attaching the FPC coverlay of Examples 5 to 8 using a resin composition containing a radical scavenger (additive) in the release layer were evaluated for breakage of the release layer, exudation of the cushion layer, followability, and release property. Although good results were obtained in the item, in Comparative Example 2 in which a resin composition containing no radical scavenger (additive) was used for the release layer, breakage of the release layer could not be suppressed.

The multilayer release film of the present invention is at a high level that could not be realized in the prior art, and has a practical high value that it can realize excellent physical properties such as fracture resistance, followability, release property, side bite prevention, cushion layer seepage suppression, etc. By bringing an effect, it has high applicability in each field of industry including the semiconductor process industry, the optical element manufacturing industry, the electronic component industry, the electrical/electronic industry, the machinery industry, and the automobile industry.

11, 21: multilayer release film
12: cutter
13: XY stage
14, 24: frame
15, 25: upper mold
16, 26: substrate
17, 27: semiconductor chip
18: sealing resin
19, 29: lower mold
19a, 29a: cavity block
19b, 29b: clamper
19c, 29c: cavity
a1: the initial depth of the cavity
a2: the final depth of the cavity
75: circuit board
76: coverlay film
71a, 71b: multilayer release film
77a, 77b: Nirvana
78a, 78b: glass cloth

Claims (14)

A multilayer film comprising a release layer (A) containing a non-crosslinkable resin and a radical scavenger, and a resin layer (B) containing an ethylene-based polymer,
A multilayer release film in which the resin layer (B) is crosslinked by electron beam irradiation,
The contact angle to water of the release layer (A) after electron beam irradiation is 90° to 130°, the multilayer release film.
According to claim 1,
The multilayer release film whose melting|fusing point calculated|required by the differential scanning calorimeter of the said release layer (A) is 200 degreeC or more.
3. The method of claim 1 or 2,
The multilayer release film, wherein the resin contained in the release layer A is at least one selected from the group consisting of α-olefin polymers, polyesters, fluorine-based resins, and polystyrene-based resins.
4. The method according to any one of claims 1 to 3,
The total content of the radical scavenger is 0.5 to 2.0% by weight based on the total weight of the release layer (A), the multilayer release film.
5. The method according to any one of claims 1 to 4,
The radical scavenger is selected from the group consisting of hindered amine light stabilizers, phenolic antioxidants, phosphorus antioxidants, polymerization inhibitors, and mixtures thereof.
6. The method according to any one of claims 1 to 5,
The radical scavenger contained in the release layer (A) comprises a hindered amine light stabilizer, a multilayer release film.
6. The method according to any one of claims 1 to 5,
The radical scavenger contained in the release layer (A) comprises a phenolic antioxidant, a multilayer release film.
6. The method according to any one of claims 1 to 5,
The radical scavenger contained in the said release layer (A), the multilayered release film containing a hindered amine light stabilizer and a phosphorus antioxidant.
9. The method according to any one of claims 3 to 8,
The α-olefin polymer contained in the release layer (A) is poly(4-methyl-1-pentene) and/or a copolymer thereof, characterized in that the multilayer release film.
9. The method according to any one of claims 3 to 8,
The polyester included in the release layer (A) is polybutylene terephthalate, characterized in that the multilayer release film.
11. The method according to any one of claims 1 to 10,
The multilayer release film which has the said release layer (A) in both surface layers, and has the said resin layer (B) in a core layer.
12. The method according to any one of claims 1 to 11,
A multilayer release film used in a printed wiring board manufacturing process or a resin encapsulation process of a semiconductor.
A multilayer film comprising a release layer (A) containing a radical scavenger and a non-crosslinkable resin, and a resin layer (B) containing an ethylene-based polymer.
A multilayer release film formed by irradiating the multilayer film of claim 13 with electron beam to crosslink the resin layer (B),
The contact angle to water of the release layer (A) after electron beam irradiation is 90° to 130°, the multilayer release film.

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