TW202200372A - Multilayer release film - Google Patents

Abstract

An object of the present invention is to provide a multilayer release film which has excellent physical properties such as break resistance, followability, releasability, prevention of side biting, and suppression of cushion layer exudation. The object is solved by the multilayer release film which is obtained by irradiating a multilayer film containing 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 with water after electron beam irradiation is 90° to 130°.

Description

Multilayer release film

The present invention relates to a multilayer release film having excellent physical properties such as fracture resistance, followability, mold release, prevention of side bite, and suppression of exudation of a cushion layer; more specifically, the present invention relates to a wide range of properties. The multi-layer release film, its manufacturing method and its use in the manufacturing process of printed circuit board or the resin sealing process of semiconductor are effectively used.

As for the release film used in the manufacturing process of printed circuit board with improved formability and followability, a multilayer film has been disclosed which has a center layer which is cross-linked by radiation such as electron rays, and which is not A release layer (surface layer) cross-linked by radiation such as electron beams. (Patent Document 1).

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

[Prior Art Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2012-179827

In view of the above-mentioned limitations of the prior art, the present invention aims to provide the following multilayer release film, preferably in the step of resin-sealing articles such as semiconductor wafers by compression molding or transfer mold molding, or In the step of attaching the cover layer of the FPC, in the case of the molded product after sealing with the semiconductor resin or the pressing of the FPC, in the former, no film breakage, resin defect, or side surface bite occurs, and the multi-layer can be easily released. It is a multi-layer release film that can be easily released without film breakage, adhesive exudation, and buffer layer exudation in the latter.

The inventors of the present invention, as a result of intensive studies to solve the above-mentioned problems, have found that the above-mentioned fractures are caused by the deterioration of the non-crosslinkable resin constituting the surface release layer due to electron beam irradiation, and have further found that by By incorporating an appropriate radical scavenger into the release layer, the deterioration can be prevented, and the present invention has been completed.

That is, the present invention is as follows.

[1] A multilayer release film obtained by subjecting "a multilayer film comprising a release layer A containing a non-crosslinkable resin and a radical scavenger, and a resin layer B containing a vinyl polymer" to electron beam irradiation Formed by crosslinking the resin layer B; wherein, 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 [1], wherein the melting point of the release layer A measured by a differential scanning calorimeter is 200° C. or higher.

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

[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 % relative 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 photostabilizers, phenolic antioxidants, phosphorus antioxidants, polymerization The group consisting of 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 photostabilizer.

[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 photostabilizer and a phosphorus-based antioxidant .

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

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

[11] The multilayer release film according to any one of [1] to [10], which has the aforementioned release layer A on both surface layers, and has the aforementioned resin layer B on the core layer.

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

[14] A multilayer release film formed by subjecting the multilayer film described in [13] to electron beam irradiation to crosslink the resin layer B; wherein, the contact of the release layer A with water after the electron beam irradiation The angle is 90° to 130°.

The multilayer release film of the present invention is capable of not damaging the followability/release properties during sealing or pressing, and suppressing film breakage during sealing or pressing, and has high practical value.

11,21: Multilayer release film

12: Cutter

13: X-Y stage

14,24: Box

15,25: Upper mold

16,26: Substrate

17,27: Semiconductor wafers

18: Sealing resin

19,29: Lower die

19a, 29a: Cavity block

19b, 29b: Gripper

19c, 29c: Mould cavity

71a, 71b: Multilayer release film

75: Circuit substrate

76: Overlay film

77a, 77b: Hot Plate

78a, 78b: Glass cloth

a ₁ : Initial depth of cavity

a ₂ : Final depth of cavity

FIG. 1 is a schematic diagram showing an example of a resin sealing process of a semiconductor wafer using the multilayer release film of the present invention.

FIG. 2 is a schematic diagram showing a test method of a peeling state after molding and the like in Examples/Comparative Examples of the present invention.

FIG. 3 is a schematic diagram illustrating a test method of a peeling state after attachment and the like in Examples/Comparative Examples of the present invention.

(Multilayer release film)

The present invention is a multi-layer release film, which comprises a release layer A containing a non-crosslinkable resin and a radical scavenger, and a multi-layer film containing a resin layer B containing a vinyl polymer for electron beam irradiation. The resin layer B is cross-linked by irradiation; wherein, the contact angle of the release layer A after the electron beam irradiation to water is 90° to 130°.

The multi-layer release film of the present invention is a laminate film comprising a release layer A having release properties to a molded product or a mold, and a resin layer B formed by electron beam cross-linking. Another aspect of the present invention is a laminated film having a release layer A on both surface layers and a resin layer B formed by electron beam cross-linking on the core layer. 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 cross-linking on a core layer, and a center layer on both sides of the core layer as desired Floor.

(release layer A)

The contact angle of the release layer A to water after electron beam irradiation is 90° to 130°. By having such a contact angle, the release layer A has low wettability and will not be adhered to the hardened sealing resin Or FPC, the surface of the mold, and the molded product 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 of the membrane surface with respect to water can be measured by a common method in the technical field, for example, it can be measured by the method described in the examples of this application.

The non-crosslinkable resin contained in the release layer A in the present invention refers to the elongation at break at room temperature measured according to the following method when compared with the elongation at break before electron beam irradiation, Resins that reduce to 20% or less after irradiating electron beams with an absorbed dose of 100 kGy at an accelerating voltage of 200 kV. Examples of such resins include alpha olefin polymers, polyesters, fluorine resin and polystyrene resin. A non-crosslinkable resin may be used individually by 1 type, and may use 2 or more types together.

(Elongation at break point)

A film with a width of 15 mm was prepared, the initial chuck gap was set to 50 mm, and the film was stretched at a rate of 300 mm/min in an environment of 23° C. The elongation at the time of film rupture was taken as the elongation at the breaking point.

(electron beam irradiation)

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

The carbon number of the alpha olefin polymer which can be used for the release layer A is 3 or more, Preferably it is 6 or more. As for the alpha olefin polymer, for example, (4-methyl-1-pentene), a polymer of octene and decene, or a copolymer with other olefin units can be mentioned. Among them, the polymer or copolymer of (4-methyl-1-pentene) is preferable.

The fluororesin which can be used for the release layer A may be a resin containing a structural unit derived from tetrafluoroethylene. It can be a homopolymer of tetrafluoroethylene or a copolymer with other olefins. Examples of other olefins contain ethylene. In terms of monomer constituting units, a preferred example is a copolymer containing tetrafluoroethylene and ethylene. In such a copolymer, the molar ratio of units based on tetrafluoroethylene and units based on ethylene (TFE/ E) is preferably 80/20 to 40/60.

As the polyester that can be used in the release layer A, polybutylene terephthalate or polyethylene terephthalate can be mentioned, for example.

The polystyrene resins that can be used in the release layer A include homopolymers and copolymers of styrene, and the structural units derived from styrene contained in the polymers are preferably at least 60% by weight Above, more preferably 80% by weight or more.

The polystyrene resin can be either co-row polystyrene or opposite row polystyrene, but from the viewpoints of transparency and easy availability, co-row polystyrene is preferred, and the release properties, From the viewpoint of heat resistance, etc., para-row polystyrene is preferable. A polystyrene may be used individually by 1 type, and may use 2 or more types together.

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

When the resin layer B of the release film is irradiated with electron beams, the surface side release layer is inevitably irradiated, but polymers of α-olefins such as (4-methyl-1-pentene) are not cross-linked. Linkable resins are structurally susceptible to decomposition by electron rays. By containing a radical scavenger in the said range, the radical generated by electron beam irradiation can be captured, and degradation can be suppressed.

The radical scavenger in the present invention can 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 free radical scavenger is preferably a hindered amine light stabilizer or a phenolic antioxidant. In addition, from the viewpoint of being able to maintain the elongation at the breaking point, a combination of a hindered amine light stabilizer and a phosphorus-based antioxidant is also preferable.

In the case of hindered amine light stabilizers (HALS), for example, hindered amine light stabilizers with NH bonds, hindered amine light stabilizers with NR bonds (R represents a monovalent hydrocarbon group), hindered amine light stabilizers with N-OR A hindered amine light stabilizer with a bond (R represents a monovalent hydrocarbon group).

For hindered amine light stabilizers having NH bonds, for example: tetrakis(2,2,6,6-tetramethyl-4-piperidinyl)butane-1,2,3,4-tetrakis Carboxylate (Tetrakis(2,2,6,6-tetramethyl-4-piperidyl)butane-1,2,3,4-tetracarboxylate) or bis(2,2,6,6-tetramethyl-4-piperidyl) Peridyl) sebacate (Bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate), which can be named as "ADK STAB LA-57" and "ADK STAB LA-77" respectively. The form is obtained by ADEKA Corporation. In addition, the latter can be obtained from BASF JAPAN Co., Ltd. in the form of "Tinuvin770".

Regarding the hindered amine light stabilizer having an N-R bond (R represents a monovalent hydrocarbon group), R can include, for example, a hydrocarbon group having a carbon number of 1 to 10, among which R is a methyl group is preferred. As such HALS, for example, tetrakis(1,2,2,6,6-tetramethyl-4-piperidinyl)butane-1,2,3,4-tetracarboxylate (Tetrakis (1,2,2,6,6-tetramethyl-4-piperidyl)butane-1,2,3,4-tetracarboxylate) or bis(1,2,2,6,6-tetramethyl-4-piperidine) Base) Sebacate (Bis(1,2,2,6,6-tetramethyl-4-piperidyl)sebacate), which can be respectively named as "ADK STAB LA-52" and "ADK STAB LA-72" The form is obtained by ADEKA Corporation.

Regarding the hindered amine light stabilizer having an N-OR bond (R represents a monovalent hydrocarbon group), for example, R may include a hydrocarbon group having a carbon number of 1 to 10. For such HALS, for example: Bis(1-undecanoxy-2,2,6,6-tetramethylpiperidin-4-yl)carbonate (Bis(1-undecanoxy-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-tetramethyl-4-piperidinyl)sebaeate), the former can be sold by ADEKA shares in the form of product name "ADK STAB LA-81" Co., Ltd., which can be obtained from BASF JAPAN Co., Ltd. under the product name "Tinuvin123".

Phenolic antioxidants include octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (Octadecyl-3-(3,5-di- tert-butyl-4-hydroxyphenyl)-propionate) (product name Irganox1076, BASF JAPAN Co., Ltd.), 2,6-di-tert-butyl-4-cresol (2,6-Di-tert-butyl-4 -methylphenol) (product name H-BHT, Honshu Chemical Industry Co., Ltd.).

Phosphorus-based antioxidants include, for example, Tris(2,4-di-tert-butylphenyl)phosphite (product name Irgafos 168, BASF JAPAN Co., Ltd.).

As a polymerization inhibitor, hydroquinone monomethyl ether, hydroquinone, phenothiazine, etc. are mentioned, for example.

The release layer A preferably has heat resistance capable of withstanding the temperature of the mold during forming (typically 120 to 180°C) or the temperature of the FPC (typically 150 to 190°C) under pressure. From this viewpoint, the melting point of the release layer A is preferably 200° C. or higher. Although the melting point does not particularly have an upper limit, the melting point of generally available crystalline resins is usually 280°C or lower.

(Resin layer B)

The resin layer B in the present invention contains an ethylene-based polymer, and forms a crosslinked structure by electron beam irradiation. Although buffering properties can be imparted by this ethylene-based copolymer, when pressure is applied while heating at a high temperature, exudation occurs due to melting of the buffer layer. Therefore, by carrying out electron beam crosslinking, it is possible to suppress bleeding while maintaining cushioning properties.

From the viewpoint of traceability to a release film of a printed circuit board or a semiconductor package, or stretchability when pressed, the vinyl-based polymer includes, for example, polyethylene, an ethylene-α-olefin copolymer, and an ethylene-acetic acid. Vinyl ester copolymers, ethylene-(meth)acrylate copolymers, ethylene-ethyl acrylate copolymers, ethylene-cycloolefin copolymers.

(other layers)

The multilayer release film of this aspect may have layers other than the release layer A and the resin layer B as long as it does not violate the purpose of the present invention. For example, between the release layer A serving as both surface layers and the resin layer B serving as the core layer, an intermediate layer may be provided if necessary. 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 off even in the resin sealing step, the release step, or the FPC pressing step.

For example, in the case where the release layer A contains 4-methyl-1-pentene copolymer, the intermediate layer may also contain polypropylene, propylene-ethylene copolymer, blends of polypropylene and polyethylene, 4- Blends of methyl-1-pentene and polyethylene, ethylene copolymers, blends of release layers and core layers, methylpentene, alpha-olefin copolymers.

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

The total thickness of the multilayer release film of the present invention is not particularly limited, but is preferably 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-mentioned range, it is preferable because the handleability when used as a roll is good and the amount of film waste is small.

(Manufacturing method of multilayer release film)

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

For the multilayer film before crosslinking, for example: 1) a method for producing a multilayer film by co-extrusion molding and laminating the release layer A and the resin layer B (co-extrusion molding method); On the film of layer B, the molten resin that will become the resin of the release layer A or the intermediate layer is coated/dried, or the resin solution that has been dissolved in the solvent to become the resin of the release layer A or the intermediate layer is coated The method of manufacturing a release film by drying (coating method); 3) The film that will become the release layer A and the film that will become the resin layer B are prepared in advance, and are manufactured by laminating these films The method of multilayer film (Laminate method), etc. Then, the multilayer release film of the present invention is obtained by subjecting the obtained multilayer film to electron beam irradiation and crosslinking the resin layer B.

(resin sealing process)

The multilayer release film of the present invention is used, for example, in a resin sealing process according to a compression molding method or a transfer molding method. When a semiconductor wafer etc. are arrange|positioned in a mold, and resin is injection-molded, the multilayer release film of this invention can be used by arrange|positioning between a semiconductor wafer etc. and the inner surface of a mold. By using the multilayer release film of the present invention, it is possible to effectively prevent poor peeling, generation of burr, and the like when peeling from a mold.

The resin used in the manufacturing process according to the above-mentioned compression molding method can be any of thermoplastic resins and thermosetting resins, but in this technical field, thermosetting resins are widely used, especially the use of ring-shaped resins. Oxygen-based thermosetting resins are preferred.

In this technical field, thermosetting resins are widely used as resins used in the manufacturing process according to the above-mentioned transfer molding method, and epoxy-based thermosetting resins are particularly preferred.

The resin sealing process using the multi-layer release film of the present invention can be appropriately adopted in the prior art in the technical field without particular limitation. Preferably, the process of each step of 1. to 9. shown in FIG. 1 is performed in sequence.

More specifically, in the step of "1. Film cutting", the multilayer release film 11 of the present invention is pulled out from a roll, unrolled on an XY stage 13, and cut into predetermined pieces. size. The predetermined size of the multi-layer release film 11 is not particularly limited, but it is preferable to cover the entire surface of the cavity 19c provided in the mold 19 used in the resin sealing process, and include a The size of the fixed place where the film 11 is sandwiched between the clamper 19b constituting the lower mold 19 and the upper mold 15 and fixed.

Next, in the step of "2. Frame type setting", the frame 14 having a shape roughly overlapping the above-mentioned fixing place is unfolded on the above-mentioned XY stage 13, and on the multi-layer release film 11 that has been cut to a predetermined size, Set up in such a way as to roughly overlap with the above-mentioned fixing points.

Next, in the step of "3. Resin measurement", a predetermined amount of the sealing resin 18 is measured and disposed on the above-mentioned multilayer release film 11 and in the above-mentioned frame 14 . The amount of the sealing resin 18 is not particularly limited, but is expected to be approximately the same as the volume of the cavity 19c after the step of "8. Compression" described later.

Then, in the step of "4. Resin + film transport", the above-mentioned multilayer release film 11 is in the state of being adsorbed on the above-mentioned frame 14, and the sealing resin 18 that has been arranged on the release film 11 is attached. It is separated from the X-Y stage 13 and transported together, and is placed on the mold 19 under resin sealing. At this time, it is preferred that the multilayer release film 11 covers the cavity 19c provided in the lower mold 19, and the sealing resin 18 disposed on the multilayer release film 11 is disposed on the cavity 19c.

Next, in the step of "5. Vacuum suction", while the fixing point of the above-mentioned multilayer release film 11 is fixed between the above-mentioned frame 14 and the holder 19b constituting the lower mold 19, the above-mentioned lower mold 19 is located at the same time. The suction holes provided in the cavity 19c are used for degassing, and the above-mentioned multilayer release film 11 is sucked and supported along the inner surface of the cavity 19c. At this time, the fixing part of the release film 11 for the above-mentioned process can also be fixed by suction through the suction holes provided in the peripheral part of the lower mold 19 .

By being sucked and supported along the inner surface of the mold cavity 19c in a state where the fixed portion at the film peripheral portion is fixed, the above-mentioned multilayer release film is stretched by a length approximately equal to the depth of the mold cavity. The (initial) depth of the cavity 19c in this step can be appropriately set according to the thickness of the resin-sealed semiconductor element 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 10.0 mm, but is not limited thereto.

In this step, the multi-layer release film 11 preferably has the flexibility to be easily sucked and supported along the inner surface of the mold cavity 19c, and has heat resistance capable of withstanding the heating temperature of the molds 15 and 19 at the same time. Moreover, it is preferable that it is easy to release from the mold 19 after resin sealing, and can be easily peeled off by the sealing resin 18 .

Furthermore, in the step of "6. Substrate setting", the substrate 16 on which the semiconductor chip 17 (and optional circuit components) are mounted is placed so that the semiconductor chip 17 faces downward. It is adsorbed on the upper mold 15 , and the upper mold 15 is moved and aligned in such a manner that the semiconductor wafer 17 is positioned approximately in the center of the cavity 19 c in the lower mold 19 .

Next, in the step of "7. Clamping", the upper mold 15 and the lower mold 19 are moved while maintaining the state of the space of the original cavity 19c (the state in which the cavity block 19a in the lower mold 19 is in the original position). Contact to close the mold.

Then, in the step of "8. Compression", the cavity block 19a is raised, and the sealing resin 18 in the cavity 19c is compressed and molded. Thereby, the semiconductor chip 17 (and optionally 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 1.0 mm or more, more preferably 1.3 mm or more, and particularly preferably 1.6 mm or more. When resin-sealing a semiconductor wafer 17 having a large thickness 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 larger. In such a case, the multilayer release film of the present invention can appropriately resin-encapsulate the semiconductor wafer 17 having a large thickness while effectively suppressing problems such as poor peeling.

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

During compression molding, it is preferable to heat the sealing resin 18 to a temperature at which the sealing resin 18 exhibits appropriate fluidity. In addition, when the sealing resin 18 is a thermosetting resin, it is preferable that the sealing resin after molding is sufficiently hardened. temperature and time for heating. For example, the maximum temperature in the resin sealing process can be set to 110 to 190°C, more preferably 120 to 180°C.

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

The sealing resin 18 may be either a liquid resin or a solid resin at normal temperature, but a sealing material such as one that becomes liquid by heating at the time of resin sealing can be suitably used. Specifically, the sealing resin material is mainly an epoxy resin (a thermosetting resin that can be cured by forming a cross-linked network with epoxy groups remaining in the polymer, preferably a biphenyl type) Epoxy resins, bisphenol epoxy resins, o-cresol novolak epoxy resins, etc.), as sealing resins other than epoxy resins, polyimide resins (repetitions in the main chain) can be appropriately used Polymer resins with units having imide bonds, preferably bismaleimide series, etc.), polysiloxane resins (polymer resins with siloxane bonds in the repeating units of the main skeleton, preferably Thermosetting addition type, etc.) are generally used as sealing resins.

Next, in the step of "9. Mold opening (mold release)", the upper mold 15 is separated from the lower mold 19, and the molded product (resin-sealed semiconductor wafer) is taken out of the mold. At this time, it is preferable that the molded product is easily peeled off from the multi-layer release film 11 , and it is particularly preferable that the multi-layer release film 11 on the side of the cavity 19c is not bitten into the molded product. Moreover, it is preferable that the surface of the molded article after peeling does not have a resin defect etc., and has a favorable appearance. If the multilayer release film of the present invention is used, it becomes easy to achieve such a better result.

(The use of multi-layer release film in the FPC cover layer attachment process)

The multilayer release film of the present invention can be disposed on the coverlay film and the coverlay film for heating and pressing in the step of laminating the circuit base material and the coverlay film that constitute the printed circuit board with the metal wiring pattern formed thereon under heat and pressure. used between hot plates, etc. By using the multi-layer release film of the present invention, it is possible to effectively prevent release defects such as self-heating disks, bleed-out of the adhesive on the cover layer film, and the like.

The adhesive on the cover layer film can be any of thermoplastic resins and thermosetting resins, but in this technical field, thermosetting resins are widely used, and epoxy-based thermosetting resins are particularly preferred. .

As far as the above manufacturing process is concerned, the lamination integration step of the circuit substrate for FPC and the coverlay film is the most representative, but not limited to this, the multilayer release film of the present invention can also be applied to non-flexible printing In the manufacturing process of circuit substrates, etc.

[Example]

Hereinafter, the present invention will be further described in detail by means of the embodiments, but the present invention is not limited in any way.

In the following examples/comparative examples/manufacturing examples, the evaluation of physical properties/characteristics was carried out by the following methods.

(Contact angle for water (water contact angle))

In accordance with JIS R3257, the contact angle of water on the surface of the release layer A after the electron beam irradiation was measured using a contact angle meter (manufactured by Kyowa Interface Science Co., Ltd., FACECA-W).

(Elongation at break point)

The single-layer release film produced in the production example was used, and the initial gap between the clips was set to 50 mm, and the film was stretched in the TD direction at 300 mm/min in an environment of 23°C. to measure. The measurement direction was set to the TD direction (the width direction at the time of film production).

In the evaluation system, the value of the elongation at the breaking point after irradiation with an absorbed dose of electron beam of 100 kGy at an accelerating voltage of 200 kV, compared with the value of the elongation at the breaking point before the irradiation of the electron beam, was evaluated as "○", A case where 20% or less is displayed is evaluated as "X".

(Releasability: Semiconductor resin sealing)

Using the multilayer release films produced in each of the examples/comparative examples, resin sealing of the semiconductor wafer was performed in the process shown in FIG. 1 .

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

The detailed conditions of "4. Resin + film transport", "5. Vacuum suction", "7. 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 ₁ of the cavity 29c at the initial stage of mold clamping is 2.4 mm, in Fig. 2(b), the width of the cavity 29c is 54 mm, and in Fig. 2(b), the paper surface of the cavity 29c is vertical The length of the direction is 221mm. In Figure 2(c), the final depth a ₂ of the mold cavity after mold clamping and compression is 0.8mm. In addition, the temperature of the molding die (molding temperature) 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 mold is lifted, 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.

⊚: The release film was naturally peeled off at the same time as the mold was opened.

○: The release film does not peel off naturally, but peels off easily when pulled by hand (when tension is applied).

×: The release film was in close contact with the resin sealing surface of the semiconductor package and could not be peeled off by hand.

(Releasability: FPC cover attached)

Using the device shown in FIG. 3, the cover layer film 76 is disposed on both sides of the circuit substrate 75, and the release film 71a or 72b and the glass cloth 78a or 78b are sequentially stacked on both sides of the cover layer film 76. The disks 77a or 77b were bonded by heating and pressing at a temperature: 180° C., pressure: 10 MPa, heating and pressing time: 130 seconds (pre-pressing: 10 seconds, main pressing: 120 seconds), and flexible printing was produced. substrate.

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

2) As the coverlay film 76, a polyimide film having a thickness of 12.5 μm which is a flexible resin base material and an adhesive layer of 25 μm in thickness (manufactured by NIKKAN INDUSTRIES Co., Ltd., trade name: CISV1225DB) was used.

Here, the coverlay film 76 is punched with a plurality of portions (openings) corresponding to the terminal portions of the circuit substrate 75 . The size of the opening of the coverlay film 76 is 4 mm×7 mm.

3) When the circuit substrate 75 and the cover layer film 76 are overlapped, the copper wiring of the former and the adhesive layer of the latter are arranged in an opposite manner, and when the cover layer film 76 and the release film 71a are overlapped, the former polyimide The film layer and the latter release layer are arranged in an opposite manner.

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

○: Can be easily peeled off from the flexible printed circuit board

×: It is attached to a flexible printed circuit board and cannot be easily peeled off

(Fracture of release layer: semiconductor resin sealing)

The rupture property of the release film at the time of releasing in the above-mentioned steps was evaluated according to the following criteria.

○: After resin sealing, after releasing the release film from the semiconductor package, the film is not broken

×: After resin sealing, the film was cracked after the release film was released from the semiconductor package

(Fracture of the release layer: FPC cover layer attachment)

The rupture property of the release film at the time of releasing in the above-mentioned steps was evaluated according to the following criteria.

○: After heating and pressing, after the release film is released from FPC, the film is not broken

×: After heating and pressing, the film was broken after the release film was released from the FPC.

(Mold followability: Semiconductor resin sealing)

The mold followability of the release film at the time of mold release in the above-mentioned steps was evaluated based on the following criteria.

○: In the semiconductor package, there is no resin deficiency at all (the part not filled with resin); or in the end portion of the semiconductor package, there is a little resin deficiency.

×: There are many resin defects at the end of the semiconductor package; or film breakage occurs during molding.

(Following (suppression of adhesive bleed): FPC cover layer attachment)

Using the same device and film combination used in the above-mentioned evaluation of the release properties, the outflow of the adhesive on the copper wiring of the FPC after heating and pressing was measured by an optical microscope (Keyence Co., Ltd., VHX -5000) was observed, and the followability was evaluated according to the following criteria.

○: The amount of outflow at the opening is less than 25 μm

×: The amount of outflow at the opening exceeds 25 μm

(Side bite: semiconductor resin sealing)

The peeling defect caused by the side surface bite of the release film at the time of release in the above-mentioned steps was evaluated based on the following criteria.

⊚: No bite marks and no peeling defects on the side surface of the semiconductor package.

○: There is a bite mark on the side surface of the semiconductor package, but there is no peeling defect.

×: There is a bite mark on the side surface of the semiconductor package and a peeling defect occurs.

(Buffer layer bleed: FPC cover layer attached)

With the same device and film combination used in the above-mentioned evaluation of the release property, after heating and pressing, the evaluation was performed according to the degree of adhesion of the release films 78a and 78b due to the exudation of the buffer layer in the release film.

○: The release films 78a and 78b were easily peeled off, and it was judged that the buffer layer had little bleeding.

×: Since the release films 78a and 78b could not be easily peeled off, it was judged that the buffer layer had a lot of bleeding.

<Production Examples 1 to 16: Evaluation of Single-layer 50 μm Thick Film (Release Layer)>

(film making)

The composition ratio of 4-methyl-1-pentene copolymer resin (product name: TPX, brand name: DX818, melting point: 232°C) made by Mitsui Chemicals Co., Ltd. 95wt% and additive (radical scavenger) 5wt% , to make a masterbatch. The type of additive (radical scavenger) used is as shown in the prescription and additive column of Table 1, and the details of the additive are as follows.

‧(Tinuvin770) Hindered Amine Light Stabilizer (HALS)

Bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate (Bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate)( BASF JAPAN Co., Ltd. Product name: Tinuvin770DF)

‧(Tinuvin123) Hindered Amine Light Stabilizer (HALS)

Bis-(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl)sebacate (Bis-(1-octyloxy-2,2,6, 6-tetramethyl-4-piperidinyl)sebacate) (product name: Tinuvin123)

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

Tetrakis(1,2,2,6,6-tetramethyl-4-piperidinyl)butane-1,2,3,4-tetracarboxylate (Tetrakis(1,2,2) ,6,6-tetramethyl-4-piperidyl)butane-1,2,3,4-tetracarboxylate) (product name: ADK STAB LA-52)

‧(LA-57): Hindered Amine Light Stabilizer (HALS)

Tetrakis (2,2,6,6-tetramethyl-4-piperidinyl)butane-1,2,3,4-tetracarboxylate (Tetrakis (2,2,6,6) -tetramethyl-4-piperidyl)butane-1,2,3,4-tetracarboxylate) (product name: ADK STAB LA-57)

‧(BHT) Phenolic Antioxidant

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

‧(Irganox1076) Phenolic antioxidant

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

‧(Irgafos168) Phosphorus antioxidant

Tris(2,4-di-tert-butylphenyl)phosphite, manufactured by BASF JAPAN Co., Ltd. (product name Irgafos 168)

Next, after blending in a manner as described in Table 1, the obtained resin composition was melt-extruded at a temperature of 270°C, and a non-stretching film with a thickness of 50 μm was prepared by adjusting the slit width of the T-die. .

(electron beam irradiation)

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

[Table 1]

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

The value of the elongation at break point 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, compared to the breaking point before electron beam irradiation Values for point elongation, showing over 20%, maintain good elongation at break.

<Examples 1 to 8, Comparative Examples 1 to 2: Evaluation of Multilayer Films>

(film making)

The resin composition blended in the composition ratio described in Table 1 above was used as the resin for the release layer.

A low-density polyethylene resin (manufactured by Du Pont Mitsui Polychemicals Co., Ltd., MIRASON 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 low-density polyethylene resin (Du Pont Mitsui Polychemicals Co., Ltd.) made of MIRASON F9673P) 60 parts by mass to produce a resin composition, which was used as a resin for the intermediate layer.

)，將上述所記載之離型層用之樹脂供給於第1擠製機，以270℃之溫度進行熔融。將芯層用之樹脂供給於第2擠製 機，以210℃之溫度進行熔融。將芯層用之樹脂供給於第3擠製機，以270℃之溫度進行熔融。 Prepare 3 extruders (each 40mm

), the resin for the release layer described above was supplied to the first extruder and melted at a temperature of 270°C. The resin for the core layer was supplied to the second extruder and melted at a temperature of 210°C. The resin for the core layer was supplied to the third extruder and melted at a temperature of 270°C.

The melted resin was guided to a distribution adapter and passed through a T-die whose temperature had been set to 270°C. The layer consisting of the release layer/intermediate layer/core layer/intermediate layer/release layer The 5-layer film of the composition was taken out.

The obtained 5-layer co-extruded film had a total thickness of 50 μm for semiconductor resin sealing, and a total thickness of 120 μm for FPC coating application.

(electron beam irradiation)

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

[Table 2]

[table 3]

The multilayer films for semiconductor resin sealing of Examples 1 to 4 in which a resin composition containing a radical scavenger (additive) was used in the release layer, and were found in the fracture of the release layer, the bite of the side surface, the mold followability, and the separation. Good results were obtained in all evaluation items of moldability. However, in Comparative Example 1 in which a resin composition not containing a radical scavenger (additive) was used in the release layer, the breakage of the release layer could not be suppressed.

Similarly, the multilayer films for attaching the FPC cover layer of Examples 5 to 8 in which the resin composition containing a radical scavenger (additive) was used in the release layer, were caused by the rupture of the release layer, the exudation of the buffer layer, and the following Good results were obtained in all the evaluation items of properties and releasability. However, in Comparative Example 2, which used a resin composition that did not contain a radical scavenger (additive) in the release layer, the breakage of the release layer could not be suppressed. .

[Industrial Availability]

The multi-layer release film system of the present invention can achieve a high level of excellent physical properties such as fracture resistance, followability, mold release, prevention of side bite, and suppression of buffer layer exudation at a high level that cannot be achieved in the prior art. It has high practical technical effect, and has high availability in various fields including the semiconductor process industry, optical component manufacturing industry, electronic parts industry, electrical and electronic industry, machinery industry, and automobile industry. sex.

Claims (14)

A multilayer release film, which is formed by subjecting a multilayer film comprising a release layer A and a resin layer B to electron beam irradiation to cross-link the resin layer B, the release layer A comprising a non-crosslinkable resin and free base scavenger, the resin layer B contains an ethylene-based polymer; wherein, The contact angle with respect to water of the release layer A after electron beam irradiation is 90° to 130°. The multilayer release film according to claim 1, wherein the melting point of the release layer A obtained by a differential scanning calorimeter is 200°C or higher. The multilayer release film according to claim 1 or 2, wherein the resin contained in the release layer A is selected from the group consisting of α-olefin polymers, polyesters, fluorine-based resins and polystyrene-based resins at least one of the groups. The multilayer release film according to any one of claims 1 to 3, wherein, relative to the total weight of the release layer A, the total amount of the radical scavenger is 0.5 to 2.0 wt %. The multilayer release film according to any one of claims 1 to 4, wherein the radical scavenger is selected from hindered amine light stabilizers, phenolic antioxidants, phosphorus antioxidants, polymerization inhibitors and the like a group of mixtures. 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. 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. 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-based antioxidant. The multilayer release film according to any one of claims 3 to 8, wherein the α-olefin polymer contained in the aforementioned release layer A is poly(4-methyl-1-pentene) and/or its Copolymer. The multilayer release film according to any one of claims 3 to 8, wherein the polyester contained in the aforementioned release layer A is polybutylene terephthalate. The multilayer release film according to any one of claims 1 to 10, comprising the aforementioned release layer A on both surface layers, and the aforementioned resin layer B on the core layer. The multilayer release film according to any one of Claims 1 to 11 is used in a printed circuit board manufacturing process or a semiconductor resin sealing process. A multilayer film comprising a release layer A containing a radical scavenger and a non-crosslinkable resin, and a resin layer B containing a vinyl polymer. A multilayer release film, which is formed by subjecting the multilayer film of claim 13 to electron beam irradiation to crosslink the resin layer B; wherein, The contact angle with respect to water of the release layer A after electron beam irradiation is 90° to 130°.

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