CN115151419A

CN115151419A - Multilayer release film

Info

Publication number: CN115151419A
Application number: CN202180016988.9A
Authority: CN
Inventors: 吉田直纪
Original assignee: Mitsui Chemicals Tohcello Inc
Current assignee: Mitsui Chemicals Tohcello Inc
Priority date: 2020-02-28
Filing date: 2021-02-22
Publication date: 2022-10-04
Anticipated expiration: 2041-02-22
Also published as: JPWO2021172257A1; KR20220143764A; CN115151419B; WO2021172257A1; JP7390467B2; TW202200372A

Abstract

The invention provides a multilayer release film which has excellent physical properties such as fracture resistance, followability, release property, prevention of biting into side surfaces, suppression of buffer layer exudation, and the like. The multilayered release film is formed by crosslinking a resin layer B by irradiating a multilayered film comprising a release layer A containing a non-crosslinkable resin and a radical scavenger and a resin layer B containing an ethylene polymer with an electron beam, wherein the contact angle of the release layer A with respect to water after the electron beam irradiation is 90 DEG to 130 deg.

Description

Multilayer release film

Technical Field

The present invention relates to a multilayer release film having excellent physical properties such as fracture resistance, conformability, releasability, prevention of biting into a side surface, and suppression of bleeding from a cushion (cushion) layer; more particularly, the present invention relates to a multilayer release film which can be widely used in a printed circuit board manufacturing process or a resin sealing process of a semiconductor, a method for manufacturing the same, and use thereof.

Background

As a release film used in a process for producing a printed circuit board having improved moldability and conformability, a multilayer film having a core layer crosslinked by radiation such as electron beam and a release layer (surface layer) not crosslinked by radiation such as electron beam has been disclosed. (patent document 1).

However, it has been pointed out that a problem of breakage of the release film occurs when an article such as a semiconductor chip (chip) is resin-sealed by a compression molding method or when a cover lay (hereinafter, also referred to as "FPC") of a flexible printed circuit board is pressed.

[ Prior art documents ]

[ patent document ]

[ patent document 1] Japanese patent laid-open No. 2012-179827.

Disclosure of Invention

[ problems to be solved by the invention ]

In view of the above-described limitations of the conventional art, the present invention has as its object to provide a multilayer release film which can be easily released without causing film breakage, resin chipping, and side biting in the former when a molded product or FPC after semiconductor resin sealing is pressed in the step of resin-sealing an article such as a semiconductor chip (chip) by compression molding or transfer molding or the step of attaching a cover sheet to an FPC, and which can be easily released without causing film breakage, adhesive bleeding, and cushion bleeding in the latter.

[ means for solving the problems ]

The present inventors have conducted extensive studies to solve the above problems, and as a result, have found that the above-mentioned breakage is caused by deterioration of a non-crosslinkable resin constituting a surface release layer by electron beam irradiation, and further found that the deterioration can be prevented by containing an appropriate radical scavenger in the release layer, and have completed the present invention.

Namely, the present invention is as follows.

[1] A multilayer release film is formed by irradiating a multilayer film comprising a release layer A and a resin layer B with an electron beam to crosslink the resin layer B, wherein the release layer A contains a non-crosslinkable resin and a radical scavenger, and the resin layer B contains a vinyl polymer; wherein the contact angle of the release layer A after the irradiation of the electron ray to the water is 90-130 deg.

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

[3] The multilayer release film according to [1] or [2], wherein the resin contained in the release layer A is at least one selected from the group consisting of an α -olefin polymer, a polyester, a fluorine-based resin, and a polystyrene-based resin.

[4] The multilayer release film according to any one of [1] to [3], wherein the total amount of the radical scavenger is 0.5 to 2.0 wt% with respect to the total weight of the release layer A.

[5] The multilayer release film 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.

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

[9] The multilayer release film 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.

[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], which comprises the release layer A on both surface layers and the resin layer B in a core layer.

[12] The release film according to any one of claims 1 to 11, which is used in a printed circuit substrate manufacturing process or a resin sealing process of a semiconductor.

[13] A multilayer film comprises a release layer A containing a radical scavenger and a non-crosslinkable resin, and a resin layer B containing a vinyl polymer.

[14] A multilayer release film formed by crosslinking a resin layer B by irradiating the multilayer film of [13] with an electron beam; wherein the contact angle of the release layer A after the irradiation of the electron ray to the water is 90-130 deg.

[ efficacy of the invention ]

The multilayer release film of the present invention can suppress the breakage of the film during sealing or pressing without impairing the following property/releasing property during sealing or pressing, and is of high value in practical use.

Drawings

Fig. 1 is a schematic view showing an example of a resin sealing process of a semiconductor chip (chip) using a multilayer release film of the present invention.

Fig. 2 is a schematic view showing a test method of a peeled state after molding in example/comparative example of the present invention.

Fig. 3 is a schematic view illustrating a test method of a peeled state after attachment in the example/comparative example of the present invention.

Detailed Description

(multilayer release film)

The present invention provides a multilayer release film, which is formed by irradiating 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 polymer with an electron beam to crosslink the resin layer B; wherein the contact angle of the release layer A after the irradiation of the electron beam to the water is 90-130 degrees.

The multilayer release film of the present invention is a laminate film including a release layer a having releasability from a molded article or a mold, and a resin layer B formed by electron beam crosslinking. Another aspect of the present invention is a laminate film having a release layer a on both surface layers and a resin layer B formed by electron beam crosslinking on a core layer. Still another aspect of the present invention is a laminate film having a release layer a on both surface layers, a resin layer B formed by electron beam crosslinking on a core layer, and intermediate layers on both sides of the core layer as desired.

(Release layer A)

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

The contact angle with water of the release layer a is more preferably 95 ° to 120 °, more preferably 98 ° to 115 °, still more preferably 100 ° to 110 °.

The contact angle with respect to water of the film surface may be measured by a method generally used in the art, and may be measured, for example, by the method described in the examples of the present application.

The non-crosslinkable resin contained in the release layer a in the present invention is a resin which reduces the elongation at break point at room temperature to 20% or less when irradiated with 100kGy of an absorbed dose of electron beam at an acceleration voltage of 200kV as compared with the elongation at break point before irradiation with electron beam, measured by the following method, and examples of the resin include α -olefin polymers, polyesters, fluorine-based resins, and polystyrene-based resins. The non-crosslinkable resin may be used alone in1 kind, or may be used in combination of 2 or more kinds.

(elongation at breaking Point)

A film having a width of 15mm was prepared, the film was stretched at 23 ℃ at 300mm/min with an initial chuck (chuck) interval of 50mm, and the elongation at break of the film was defined as the elongation at break point (electron beam irradiation)

For the film sample, electron rays were irradiated at an accelerating voltage of 200kV and at an absorbed dose of 100 kGy.

The α -olefin polymer that can be used in the release layer a has 3 or more carbon atoms, and more preferably 6 or more carbon atoms. As the alpha olefin polymer, there may be mentioned, for example: 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 more preferable.

The fluororesin usable in the release layer a may be a resin containing a constituent unit derived from tetrafluoroethylene. It may be a homopolymer of tetrafluoroethylene or a copolymer with other olefins. Examples of other olefins include ethylene. A more preferred example of the monomer constituent units is a copolymer comprising tetrafluoroethylene and ethylene, and the molar ratio of units based on tetrafluoroethylene to units based on ethylene (TFE/E) in such a copolymer is more preferably from 80/20 to 40/60.

Examples of polyesters that can be used in the release layer a are polybutylene terephthalate or polyethylene terephthalate.

The polystyrene resin used in the release layer a contains a homopolymer and a copolymer of styrene, and the styrene-derived structural unit contained in the polymer is preferably at least 60 wt%, more preferably 80 wt% or more.

The polystyrene resin may be homopolystyrene or syndiotactic polystyrene, but from the viewpoint of transparency, easy availability and the like, homopolystyrene is more preferable, and from the viewpoint of releasability, heat resistance and the like, syndiotactic polystyrene is more preferable. The polystyrene may be used alone in1 kind, or 2 or more kinds may be used in combination.

The release layer a in the present invention contains a radical scavenger. More preferably, the release layer a contains 0.5 to 2.5 wt% of the radical scavenger, more preferably 0.5 to 2.0 wt%, relative to the total weight of the release layer a.

When the resin layer B of the release film is irradiated with an electron beam, the release layer on the front surface side is inevitably irradiated, but a non-crosslinkable resin such as a polymer of an α -olefin including (4-methyl-1-pentene) is structurally susceptible to decomposition by an electron beam. By containing the radical scavenger in the above range, radicals generated by electron beam irradiation can be trapped, and degradation can be suppressed.

The radical scavenger in the present invention may be 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.

The radical scavenger is preferably a hindered amine light stabilizer or a phenol antioxidant. In addition, a combination of a hindered amine light stabilizer and a phosphorus antioxidant is also preferable from the viewpoint of maintaining elongation at break.

As the Hindered Amine Light Stabilizer (HALS), for example, 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), a hindered amine light stabilizer having an N-OR bond (R represents a monovalent hydrocarbon group) can be exemplified.

As the hindered amine light stabilizer having an N-H bond, for example: tetrakis (2,2,6,6-tetramethyl-4-piperidinyl) butane-1,2,3,4-tetracarboxylate (Tetrakis (2,2,6,6-tetramethy-4-piperidinyl) butane-1,2,3,4-tetracarboxylate) or Bis (2,2,6,6-tetramethyl-4-piperidinyl) sebacate (Bis (2,2,6,6-tetramethy-4-piperidinyl) sebate), available as product names "ADK STAB LA-57" and "ADK STAB LA-77", respectively, from ADEKA corporation. In addition, the latter can be obtained in the form of "Tinuvin770" by BASF JAPAN corporation.

As the hindered amine light stabilizer having an N — R bond (R represents a monovalent hydrocarbon group), for example, a hydrocarbon group having 1 to 10 carbon atoms is exemplified as R, and a methyl group is more preferable. As such HALS, there may be mentioned, for example: tetrakis (1,2,2,6,6-tetramethyl-4-piperidinyl) butane-1,2,3,4-tetracarboxylate (Tetrakis (1,2,2,6,6-tetramethy-4-piperidinyl) butane-1,2,3,4-tetracarboxylate) or Bis (1,2,2,6,6-tetramethyl-4-piperidinyl) sebacate (Bis (1,2,2,6,6-tetramethy-4-piperidinyl) sebate), respectively, are available from ADEKA, inc. under the trade names "ADK STAB LA-52" and "ADK STAB LA-72", respectively.

As the hindered amine light stabilizer having an N — OR bond (R represents a monovalent hydrocarbon group), R may be exemplified by a hydrocarbon group having a carbon number =1 to 10. As such HALS, mention may be made, for example: bis (1-undecoxy-2,2,6,6-tetramethylpiperidin-4-yl) carbonate (Bis (1-undecoxy-2,2,6,6-tetramethylpiperidin-4-yl) carbonate), bis (1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate (Bis- (1-octyloxy-2,2,6,6-tetramethy-4-piperidinyl) sebactate), the former available under the product name "ADK STAB LA-81" from ADEKA corporation and the latter available under the product name "Tinuvin123" from BASF ja corporation.

As the phenolic antioxidant, octadecyl-3- (3,5-Di-t-butyl-4-hydroxyphenyl) propionate (Octadecyl-3- (3,5-Di-t-butyl-4-hydroxyphenyl) -propionate) (product name Irganox1076, BASF JAPAN Co., ltd.), 2,6-Di-t-butyl-4-methylphenol (product name H-BHT, chemical industry Co., ltd., state) can be exemplified.

As the phosphorus-based antioxidant, tris (2,4-di-tert-butylphenyl) phosphite (Tris (2,4-di-tert. -butyl phenyl) phosphate) (product name Irgafos168, BASF JAPAN Co., ltd.) may, for example, be mentioned.

As the polymerization inhibitor, hydroquinone monomethyl ether, hydroquinone, phenothiazine (phenothiazine), etc. are exemplified.

The release layer a preferably has heat resistance capable of withstanding the temperature of a mold at the time of molding (typically 120 to 180 ℃) or the temperature at the time of pressing of FPC (typically 150 to 190 ℃). From this viewpoint, the melting point of the release layer a is preferably 200 ℃. The melting point is not particularly limited, but generally, the melting point of a crystalline resin which can be obtained is much 280 ℃ or lower.

(resin layer B)

The resin layer B in the present invention contains a vinyl polymer and forms a crosslinked structure by irradiation with an electron beam. Although the ethylene copolymer can provide cushioning properties, when pressure is applied while heating at high temperature, bleeding occurs due to melting of the cushion layer. Thus, by performing electron beam crosslinking, bleeding can be suppressed while maintaining the cushioning properties.

From the viewpoint of traceability to a release film of a printed circuit board or a semiconductor package, or stretchability under pressure, examples of the ethylene polymer include polyethylene, ethylene- α -olefin copolymer, ethylene-vinyl acetate copolymer, ethylene- (meth) acrylate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-cycloolefin copolymer.

(other layers)

The multilayer release film of the present embodiment may have layers other than the release layer a and the resin layer B as long as the object of the present invention is not violated. For example, an intermediate layer may be optionally provided between the release layer a as both surface layers and the resin layer B as a core layer. The material used for the intermediate layer is not particularly limited as long as it can firmly adhere the release layer a and the resin layer B and peeling does not occur even in the resin sealing step, the release step, and the pressing step of the FPC.

For example, in the case where the release layer A comprises a 4-methyl-1-pentene copolymer, the intermediate layer may also comprise polypropylene, propylene-ethylene copolymer, a blend of polypropylene and polyethylene, a blend of 4-methyl-1-pentene and polyethylene, an ethylene copolymer, a blend of release layer and core layer, methylpentene, alpha-olefin copolymer.

The thickness of the intermediate layer is not particularly limited as long as it can improve the adhesion between the release layer a and the resin layer B, but is, for example, 0.5 to 10 μm.

The total thickness of the multi-layer release film of the present invention is not particularly limited, but is preferably, for example, 10 to 300 μm, more preferably 30 to 150 μm, and most preferably 50 to 120 μm. When the total thickness of the multilayer release film is within the above range, handling properties when used as a roll good, and the amount of film discarded is small, which is preferred.

(method for producing multilayer Release film)

The multilayer release film of the present invention can be produced by any method.

The multilayer film before crosslinking can employ, for example: 1) A method of producing a multilayer film by co-extrusion molding and laminating the release layer a and the resin layer B (co-extrusion molding method); 2) A method (coating method) of coating/drying a molten resin of a resin to be a release layer a or an intermediate layer on a film to be a resin layer B, or coating/drying a resin solution in which a resin to be a release layer a or an intermediate layer is dissolved in a solvent, to manufacture a release film; 3) A method (a Laminate method) of manufacturing a multilayer film by laminating (laminating) films to be a release layer a and a resin layer B, and the like. Then, the obtained multilayer film is irradiated with an electron beam to crosslink the resin layer B, thereby obtaining the multilayer release film of the present invention.

(resin sealing Process)

The multilayer release film of the present invention is used in a resin sealing process performed, for example, according to a compression molding method or a transfer molding method. When a semiconductor chip (chip) or the like is placed in a mold and resin is injected and molded, the multilayer release film of the present invention can be used by being placed between the semiconductor chip (chip) or the like and the inner surface of the mold. By using the multilayer release film of the present invention, peeling failure, generation of burrs (burr), and the like can be effectively prevented when peeling from a mold.

The resin used in the production process by the compression molding method may be either a thermoplastic resin or a thermosetting resin, but thermosetting resins are widely used in this field of technology, and it is particularly preferable to use an epoxy-based thermosetting resin.

Resins used in the production process by the transfer molding method are widely used in the art, and particularly, epoxy-based thermosetting resins are preferably used.

The resin sealing process using the multilayer release film of the present invention can be suitably applied to a process which has been conventionally known in the art and is not particularly limited, but for example, in the case of a resin sealing process of a semiconductor chip (chip) by a compression molding method, it is more preferable to sequentially perform the steps of 1.9 shown in fig. 1.

More specifically, in the "1. Film cutting" step, the multilayer release film 11 of the present invention is first pulled out from a roll, unwound on an X-Y table (stage) 13, and cut into a predetermined size. The predetermined size of the multilayer release film 11 is not particularly limited, but is preferably: the entire surface of a cavity 19c provided in a lower mold 19 used in a resin sealing process is covered, and the size of a fixing portion for fixing the film 11 by sandwiching it between a clamper (clamp) 19b constituting the lower mold 19 and the upper mold 15 is included.

Next, in the "2-frame setting" step, a frame 14 having a shape approximately overlapping the fixed portion is developed on the X-Y table 13, and is set on the multi-layer release film 11 cut to a predetermined size so as to approximately overlap the fixed portion.

Next, in the "3 resin metering" step, a predetermined amount of the sealing resin 18 is metered and placed on the multilayer release film 11 and in the frame 14. The amount of the sealing resin 18 is not particularly limited, but is desirably approximately the same as the volume of the cavity 19c after the "8-compression" step described later.

Then, in the "4. Resin + film transfer" step, the multilayer release film 11 is separated from the X-Y table 13 and transferred together with the sealing resin 18 already disposed on the release film 11 in a state of being adsorbed to the frame 14, and is disposed on the lower mold 19 to be resin-sealed. In this case, it is preferable that the multi-layer release film 11 is disposed so as to cover the cavity 19c of the lower mold 19, and the sealing resin 18 disposed on the multi-layer release film 11 is disposed so as to be positioned on the cavity 19 c.

Next, in the "5. Vacuum suction" step, while fixing the fixed position of the multilayer release film 11 between the frame 14 and the holder 19b constituting the lower mold 19, the suction hole provided in the cavity 19c of the lower mold 19 is used to degas, and the multilayer release film 11 is suction-supported along the inner surface of the cavity 19 c. In this case, the fixing position of the release film for process 11 may be fixed by suction through a suction hole provided in the peripheral edge portion of the lower mold 19.

The multilayer release film is stretched by a length approximately corresponding to the depth of the cavity by being sucked and supported along the inner surface of the cavity 19c in a state where the fixing portions at the peripheral edge of the film are fixed. The (initial) depth of the cavity 19c in this step can be appropriately set in accordance with the thickness of the resin-sealed semiconductor device produced by the resin sealing process of the present embodiment. The (initial) depth of the cavity 19c in this step is usually 1.0 to 10.0mm, but is not limited thereto.

In this step, the multilayer release film 11 preferably has flexibility that is easily sucked and supported along the inner surface of the cavity 19c and heat resistance that can withstand the heating temperature of the molds 15 and 19. It is preferable that the mold 19 is easily released after resin sealing and the sealing resin 18 can be easily released.

In the "6 th substrate setting" step, the substrate 16 on which the semiconductor chip (chip) 17 (and optional circuit components) is mounted is sucked to the upper mold 15 so that the semiconductor chip (chip) 17 faces downward, and the upper mold 15 is moved so that the semiconductor chip (chip) 17 is positioned at the approximate center of the cavity 19c in the lower mold 19, thereby aligning the positions.

Next, in the "7-step mold clamping", the upper mold 15 and the lower mold 19 are brought into contact with each other and clamped while maintaining the space of the first cavity 19c (the cavity block 19a of the lower mold 19 is in the initial position).

Then, in the "8. Compression" step, the cavity block 19a is raised to perform compression molding of the sealing resin 18 in the cavity 19 c. Accordingly, the semiconductor chip (chip) 17 (and optional circuit parts) on the substrate 16 is sealed by 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 1.0mm or more, more preferably 1.3mm or more, and particularly preferably 1.6mm or more. In the case of resin-sealing a semiconductor chip (chip) 17 having a large thickness such as a NAND flash memory having a large capacity, the difference between the initial depth of the cavity 19c and the final depth of the cavity 19c after compression molding tends to be large, and even in such a case, the multilayer release film of the present invention can suitably resin-seal the semiconductor chip (chip) 17 having a large thickness while effectively suppressing problems such as peeling failure.

The final depth (resin thickness after compression molding) of the cavity 19c is preferably 0.5mm or more, more preferably 0.7mm or more, and particularly preferably 1.0mm or more. By setting the final depth of the cavity 19c to 0.5mm or more, a semiconductor chip (chip) 17 having a large thickness, such as a NAND flash memory having a large capacity, can be appropriately sealed with resin.

In the compression molding, it is preferable to heat the sealing resin 18 to a temperature at which the sealing resin 18 exhibits appropriate fluidity, and in the case where the sealing resin 18 is a thermosetting resin, it is preferable to heat the sealing resin at a temperature and for a time at which the molded sealing resin is sufficiently cured. For example, the maximum temperature in the resin sealing process can be set to 110 to 190 ℃, and more preferably to 120 to 180 ℃.

The molding pressure and the curing time at this time are not particularly limited, and may be set to appropriate preferable conditions according to the type of the sealing resin 18 and the sealing temperature, but may be set appropriately within a range of, for example, 50 to 300kN, more preferably 70 to 150kN, and 1 to 60 minutes, more preferably 2 to 10 minutes.

The sealing resin 18 may be a liquid resin or a resin that is solid at room temperature, but a sealing material that is liquid by heating at the time of resin sealing or the like can be suitably used. Specifically, as the sealing resin material, an epoxy resin (a thermosetting resin which can be cured by forming a crosslinked network with epoxy groups remaining in a polymer, preferably a biphenyl type epoxy resin, a bisphenol epoxy resin, an o-cresol novolac type epoxy resin, or the like) is mainly used, and as the sealing resin other than the epoxy resin, a polyimide resin (a polymer resin having imide bonds in repeating units of a main chain, preferably a bismaleimide type or the like), a silicone resin (a polymer resin having siloxane bonds in repeating units of a main skeleton, preferably a thermosetting addition molding or the like) or the like is usually used as the sealing resin.

Next, in the "9-opening (releasing)" step, the upper mold 15 is separated from the lower mold 19, and the molded product (resin-sealed semiconductor chip) is taken out of the mold. In this case, it is more preferable that the molded article is easily peeled from the multilayer release film 11, and particularly preferable that the multilayer release film 11 on the side surface of the cavity 19c is peeled in a state where it does not bite into the molded article. Further, it is preferable that the surface of the molded article after peeling has a good appearance without resin shortage or the like. Such a more preferable result becomes easy to achieve if the multilayer release film of the present invention is used.

(use of multilayer Release film in FPC coverlay attachment Process)

The multilayer release film of the present invention can be used by being disposed between a cover lay film and a hot plate for heating and pressing in a step of laminating a circuit substrate having a metal wiring pattern formed thereon and the cover lay film constituting a printed circuit board by heating and pressing. By using the multilayer release film of the present invention, release failure from a hot plate or the like, bleeding of an adhesive on a cover film, and the like can be effectively prevented.

The adhesive on the cover layer film may be any of a thermoplastic resin and a thermosetting resin, but thermosetting resins are widely used in the art, and epoxy thermosetting resins are particularly preferably used.

The step of integrating the circuit substrate for FPC and the cover lay film by lamination is most representative of the above manufacturing process, but the present invention is not limited thereto, and the multilayer release film of the present invention can be applied to a manufacturing process of a non-flexible printed circuit board, and the like.

[ examples ]

The present invention will be described in further detail with reference to examples, but the present invention is not limited thereto.

In the following examples, comparative examples and production examples, physical properties and characteristics were evaluated by the following methods.

(contact Angle with Water (Water contact Angle))

The water contact angle of the surface of the release layer A after electron beam irradiation was measured according to JIS R3257 using a contact angle measuring apparatus (FACECA-W, manufactured by Kyowa interface Science Co., ltd.).

(elongation at breaking Point)

The single-layer release film produced in the production example was stretched in the TD direction at 300mm/min in an environment of 23 ℃ with an initial nip distance set at 50mm, and the elongation at break of the film was measured as the elongation at break point. The measurement direction was set to the TD direction (width direction in film production).

Evaluation the value of elongation at break point after irradiation of 100kGy of absorbed dose of electron ray at an acceleration voltage of 200kV, the case showing more than 20% was evaluated as "good" and the case showing 20% or less was evaluated as "x" in comparison with the value of elongation at break point before irradiation of electron ray.

(Release: semiconductor resin seal)

Using the multi-layer release film fabricated in each example/comparative example, resin sealing of a semiconductor chip (chip) was performed by the process shown in fig. 1.

The sealing resin used was an epoxy lead frame sealing material (trade name: CEL-9750ZHF 10) manufactured by Hitachi chemical industries, ltd.

The detailed conditions of "4. Resin + film conveyance", "5. Vacuum suction", and "7 mold clamping" and "9. Compression" in the process of fig. 1 are shown in fig. 2 (a), (b), and (c). In fig. 2 (a), the depth a of the cavity 29c at the initial stage of mold clamping ₁ 2.4mm, the width of the cavity 29c is 54mm in fig. 2 (b), the length of the cavity 29c in the direction perpendicular to the paper surface is 221mm in fig. 2 (b), and the final depth a of the cavity after mold clamping and compression is shown in fig. 2 (c) ₂ Is 0.8mm. The temperature (molding temperature) of the molding die was 175 ℃, the molding pressure was 96kN, and the molding time was 120 seconds.

Then, the upper mold is lifted up in a manner shown as "9-opening mold (release)" in fig. 1, and the resin-sealed semiconductor chip (semiconductor package) is released from the release film. The release properties of the release film were evaluated according to the following criteria.

Excellent: the release film is naturally peeled off simultaneously with the opening of the mold.

Good component: the release film did not peel off naturally, but peeled off easily when pulled by hand (when tension was applied).

X: the release film was tightly adhered to the resin sealing surface of the semiconductor package and could not be peeled off by hand.

(Release: FPC coverlay attachment)

Using the apparatus having the configuration shown in fig. 3, the coverlay films 76 were disposed on both sides of the circuit substrate 75, and the release film 71a or 72b and the

glass cloth

78a or 78b were sequentially stacked on both sides thereof, and the

heat plate

77a or 77b was used to heat the circuit substrate at a temperature: 180 ℃ and pressure: 10MPa, heating and pressurizing time: the substrates were bonded to each other by heating and pressing for 130 seconds (prepressing: 10 seconds, main pressing: 120 seconds) to produce a flexible printed board.

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

2) As the cover layer film 76, a cover layer film in which an adhesive layer having a thickness of 25 μm was formed on a polyimide film having a thickness of 12.5 μm, which is a flexible resin base (product name: CISV1225 DB).

A plurality of portions (openings) corresponding to the terminal portions of the circuit substrate 75 are punched out of the cover film 76. The size of the opening of the cover film 76 was 4mm × 7mm.

3) When the circuit substrate 75 and the cover film 76 are stacked, the former copper wiring and the latter adhesive layer are disposed to face each other, and when the cover film 76 and the release film 71a are stacked, the former polyimide film layer and the latter release layer are disposed to face each other.

After heating and pressing, the release film was immediately peeled off, and the release property of the release film was evaluated according to the following criteria.

Good component: can be easily peeled off from the flexible printed circuit board

X: is adhered to a flexible printed board and cannot be easily peeled off

(fracture of Release layer: semiconductor resin sealing)

The fracture property of the release film when releasing was performed in the above-described step was evaluated according to the following criteria.

Good: after resin sealing, the release film is released from the semiconductor package without breaking

X: after resin sealing, the release film is released from the semiconductor package, and the film is broken

(breaking of Release layer: FPC coverlay attachment)

The fracture properties of the release film when releasing was performed in the above-described steps were evaluated according to the following criteria.

Good: after heating and pressurizing, the release film is released from the FPC, and the film is free from cracking

X: after heating and pressing, the release film is released from the FPC, and the film has cracks

(mold following property: semiconductor resin sealing)

The mold-following property of the release film when releasing was performed in the above-described step was evaluated according to the following criteria.

Good component: in the semiconductor package, there is no resin shortage (portion not filled with resin) at all; or at the end of the semiconductor package, some resin is missing.

X: at the end of the semiconductor package, there are many resin defects; or film breakage occurs during forming.

( Following property (suppressing adhesive bleeding): FPC coverlay attachment )

The amount of adhesive flowing out of the copper wiring of the FPC after heating and pressing was observed by an optical microscope (VHX-5000, manufactured by Keyence, ltd.) using the same apparatus and film combination as those used for the evaluation of the releasability, and the followability was evaluated based on the following criteria.

Good component: the outflow rate at the opening is less than 25 μm

X: the outflow rate at the opening is more than 25 μm

(side bite: semiconductor resin seal)

The peeling failure due to the side biting of the release film when releasing was performed in the above-described procedure was evaluated according to the following criteria.

Very good: there was no undercut nor peeling failure on the side face of the semiconductor package.

Good component: there was a bite mark on the side surface of the semiconductor package, but no peeling failure was observed.

X: there was a bite mark on the side surface of the semiconductor package and a peeling failure occurred.

(buffer layer exudation: FPC coverlay attachment)

Evaluation was made in accordance with the degree of adhesion of the

release films

78a and 78b due to the bleed-out of the buffer layer in the release film after heat-pressing in the same apparatus and film combination as used in the above-described evaluation of release properties.

Good: the

release films

78a and 78b can be easily peeled off, and the bleed-out of the buffer layer is judged to be small.

X: since the

release films

78a and 78b cannot be easily peeled off, it was judged that the buffer layer bleeds out much.

Production examples 1 to 16: evaluation of Single-layer 50 μm-thick film (Release layer) >

(film making)

A master batch was prepared by mixing 95wt% of 4-methyl-1-pentene copolymerized resin (product name: TPX, brand name: DX818, melting point: 232 ℃) manufactured by Mitsui chemical Co., ltd., and 5wt% of an additive (radical scavenger). The types of the additives (radical scavenger) used were as shown in the recipe and additive column of table 1, and the details of the additives are as follows.

(Tinuvin 770) Hindered Amine Light Stabilizer (HALS)

Bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate (Bis (2,2,6,6-tetramethyl-4-piperidyl) sebate, manufactured by BASF JAPAN GmbH) (product name: tinuvin770 DF)

(Tinuvin 123) Hindered Amine Light Stabilizer (HALS)

Bis (1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate (Bis- (1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate manufactured by BASF JAPAN GmbH) (product name: tinuvin 123)

(LA-52) Hindered Amine Light Stabilizer (HALS)

Tetracarboxylic acid ester (Tetrakis (1,2,2,6,6-tetramethyl-4-piperidinyl) butane-1,2,3,4-tetracarboxylate) manufactured by ADEKA GmbH (1,2,2,6,6-tetramethyl-4-piperidinyl) butane-3452 (product name: ADK STAB LA-52)

(LA-57): hindered Amine Light Stabilizers (HALS)

Tetracarboxylic acid ester (Tetrakis (2,2,6,6-tetramethyl-4-piperidinyl) butane-1,2,3,4-tetracarboxylate) manufactured by ADEKA GmbH (2,2,6,6-tetramethyl-4-piperidinyl) butane-3252 (product name: ADK STAB LA-57)

Phenol series (BHT) antioxidant

2,6-Di-tert-butyl-4-methylphenol (2,6-Di-tert-butyl-4-methylphenol) manufactured by Benzhou chemical industry Co., ltd. (product name: H-BHT)

(Irganox 1076) phenol-based antioxidant

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

(Irgafos 168) phosphorus based antioxidant

Tris (2,4-di-tert-butylphenyl) phosphite (Tris (2,4-di-tert. -butyl phenyl) ph17 ospite) manufactured by BASF JAPAN GmbH (product name Irgafos 168)

Subsequently, the resin compositions were melt-extruded at a temperature of 270 ℃ after blending so as to obtain the formulations shown in Table 1, and the slit width of the T die was adjusted to obtain a non-drawn film having a thickness of 50 μm.

(Electron beam irradiation)

The obtained single-layer 50 μm-thick film was irradiated with 100kGy of absorbed dose of electron rays at an accelerating voltage of 200kV by an electron ray irradiation apparatus. The evaluation results are shown in table 1.

[ Table 1]

The single-layer resin film (production example 16) containing no radical scavenger (additive) had a breaking point elongation of 553%, but the breaking point elongation of the film after electron beam irradiation was reduced to 5% (production example 11), and the breaking point elongation after electron beam irradiation was reduced to less than 1% compared to that before irradiation.

The values of elongation at break points of the single-layer resin films of production examples 1 to 10 containing 0.5 to 2.0 wt% of the radical scavenger (additive) relative to the total amount of the single-layer resin film showed more than 20% compared to the value of elongation at break point before electron beam irradiation, and good elongation at break points was maintained.

Examples 1 to 8, comparative examples 1 to 2: evaluation of multilayer film

(film making)

Resin compositions blended with the composition ratios shown in table 1 were used as the release layer resin.

A low-density polyethylene resin (MIRASON F9673P, manufactured by Du Pont-Mitsui Polychemicals Co., ltd.) was used as a resin for the core layer.

40 parts by mass of a 4-methyl-1-pentene copolymerized resin (product name: TPX, product name: DX818, manufactured by Mitsui Chemicals Co., ltd.) and 60 parts by mass of a low density polyethylene resin (product name: MIRASON F9673P, manufactured by Du Pont-Mitsui Polychemicals Co., ltd.) were blended to prepare a resin composition, and the resin composition was used as a resin of the intermediate layer.

3 extruders (40 mm. Phi. Each) were prepared, and the resin for the release layer described above was supplied to the 1 st extruder and melted at a temperature of 270 ℃. The resin for the core layer was supplied to the 2 nd extruder and melted at a temperature of 210 ℃. The resin for the core layer was supplied to a 3 rd extruder and melted at a temperature of 270 ℃.

The molten resin was led to a dispensing adapter (adapter), and a 5-layer film composed of a release layer/intermediate layer/core layer/intermediate layer/release layer was taken out through a T-die whose temperature had been set to 270 ℃.

The obtained 5-layer co-extrusion film had a total thickness of 50 μm for semiconductor resin sealing and 120 μm for FPC cover attachment, and the layer structures were as shown in tables 2 and 3.

(Electron beam irradiation)

The obtained multilayer film was irradiated with an electron beam at an acceleration voltage of 200kV and at the absorption dose described in table 2 and table 3. The evaluation results are shown in tables 2 and 3.

[ Table 2]

Table 2 evaluation results of multilayer film for semiconductor resin sealing

[ Table 3]

TABLE 3 evaluation results of multilayer film for FPC coverlay attachment

The multilayer films for sealing semiconductor resins of examples 1 to 4 using the resin composition containing the radical scavenger (additive) in the release layer gave good results in all the evaluation items of the fracture, biting into the side surface, mold following property, and release property of the release layer, whereas the fracture of the release layer could not be suppressed in comparative example 1 using the resin composition containing no radical scavenger (additive) in the release layer.

Similarly, the multilayer films for FPC coverlay attachment of examples 5 to 8 using the resin composition containing the radical scavenger (additive) in the release layer gave good results in all the evaluation items of the fracture, cushion layer bleed-out, follow-up property, and release property of the release layer, whereas the fracture of the release layer could not be suppressed in comparative example 2 using the resin composition containing no radical scavenger (additive) in the release layer.

[ industrial applicability ]

The multilayer release film of the present invention can achieve excellent physical properties such as fracture resistance, conformability, releasability, prevention of side biting, and suppression of buffer layer bleeding at a high level that has not been achieved in the conventional art, and can provide a technical effect of high value in practical use, and has high applicability in various fields of industries such as the semiconductor process industry, the optical element manufacturing industry, the electronic component industry, the electrical and electronic industry, the mechanical industry, and the automobile industry.

Description of the reference numerals

11,21 multilayer release film

12. Cutting knife

13 X-Y table

14,24 frame

15,25 upper die

16,26 baseplate

17,27 semiconductor chip

18. Sealing resin

19,29 lower die

19a,29a mould cavity block

19b,29b gripper

19c,29c mould cavity

a ₁ Initial depth of cavity

a ₂ Final depth of the cavity

75. Circuit substrate

76. Cover film

71a,71b multilayer release film

77a,77b hot plate

78a,78b glass cloth.

Claims

1. A multilayer release film is formed by irradiating a multilayer film comprising a release layer A and a resin layer B with an electron beam to crosslink the resin layer B, wherein the release layer A contains a non-crosslinkable resin and a radical scavenger, and the resin layer B contains a vinyl polymer; wherein the content of the first and second substances,

the contact angle of the release layer a after electron beam irradiation to water is 90 ° to 130 °.

2. The multilayer release film according to claim 1, wherein the melting point of the release layer A as determined by a differential scanning calorimeter is 200 ℃ or more.

3. The multilayer release film according to claim 1 or 2, wherein the resin contained in the release layer a is at least one selected from the group consisting of an α -olefin polymer, a polyester, a fluorine-based resin, and a polystyrene-based resin.

4. The multilayer release film according to any one of claims 1 to 3, wherein the total amount of the aforementioned radical scavenger is 0.5 to 2.0 wt% relative to the total weight of the aforementioned release layer A.

5. The multilayer release film according to any of claims 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.

6. The multilayer release film according to any one of claims 1 to 5, wherein the radical scavenger contained in the aforementioned release layer A contains a hindered amine light stabilizer.

7. The multilayer release film according to any one of claims 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 claims 1 to 5, wherein the radical scavenger contained in the release layer A contains a hindered amine light stabilizer and a phosphorus antioxidant.

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

10. The multilayer release film according to any one of claims 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 claims 1 to 10, which has the release layer a on both surface layers and the resin layer B on a core layer.

12. The multilayer release film according to any one of claims 1 to 11, used in a printed circuit substrate manufacturing process or a resin sealing process of a semiconductor.

13. A multilayer film comprises a release layer A containing a radical scavenger and a non-crosslinkable resin, and a resin layer B containing a vinyl polymer.

14. A multilayer release film formed by crosslinking a resin layer B by irradiating the multilayer film according to claim 13 with an electron beam; wherein the content of the first and second substances,