KR20180019957A - Film for flexible multilayer printed circuit board lamination using sputter-type fccl - Google Patents

Abstract

The present invention relates to a film for laminating a multilayer printed circuit board using a sputter type flexible copper clad laminate (FCCL), a multilayer printed circuit board assembly including the film, and a manufacturing method of the multilayer printed circuit board. The film of the present invention has excellent adhesive strength, excellent heat resistance and flame retardancy and excellent migration resistance in laminating circuit boards by comprising an insulating adhesive layer formed by coating an insulating adhesive composition on a surface of a polyimide film of a sputter type single-sided FCCL. Therefore, the manufacturing method according to the present invention can reduce the number of films to be laminated and can simplify the manufacturing process. Further, the film according to the present invention can refine a circuit line width by using a copper foil layer as a circuit surface in the sputter type FCCL.

Description

TECHNICAL FIELD [0001] The present invention relates to a multilayer printed circuit board (FCCL) film using a sputter-type FCCL,

The present invention relates to a multilayer printed circuit board lamination film using a sputter-type FCCL (Flexible Copper Clad Laminate). More particularly, the present invention relates to a multilayer printed circuit board lamination film using an insulating adhesive Layer for a multilayer printed circuit board lamination film excellent in adhesive strength when laminated on a circuit board, excellent in heat resistance and flame retardancy, and excellent in migration resistance, and to provide a multilayer printed circuit board lamination film using the same, To a multilayer printed circuit board assembly and a method of manufacturing the same.

Background Art [0002] Recent developments in semiconductor integrated circuits in the field of electronic industrial technology have accelerated the trend toward miniaturization, thinning, thinning, high density and high bending of circuits in electronic products.

The implementation of such a lightweight shortening and high integration is easy to use even in a more complicated and narrow space due to the development of the integration degree according to the technology development. Specifically, a flexible printed circuit board (FCCL) Laminate. ≪ / RTI > This FCCL is a structure for forming a circuit by bonding the upper and lower surfaces of the polyimide film as an insulating substrate together with a copper foil. After forming the circuit, soldering can be performed to all the upper and lower surfaces. do.

Conventional methods for producing FCCL include a casting method in which a copper foil is coated with a polyamic acid varnish, which is a precursor of polyimide, followed by imidization of polyamic acid, and a method in which a copper foil and a thermoplastic polyimide film are heat- A sputtering method in which electroplating is performed after sputtering on a polyimide film is mainly used.

In the case of a flexible printed circuit board, multilayering is inevitable due to miniaturization and multifunctionalization of electronic devices. Such multilayering is a problem in that the ductility of the flexible printed circuit board is impaired and the thickness of the circuit board is difficult to be reduced by lamination of the coverlay film and the bonding sheet have.

In order to manufacture a flexible printed circuit board, a dry film is laminated on an FCCL in which a copper foil layer is formed on one side or both sides of an insulating film such as a polyimide resin, A circuit pattern is formed by sequentially exposing, developing and etching, and then a coverlay film is applied to the outside of the FCCL and laminated using a hot press.

In order to manufacture a multilayer flexible printed circuit board, an inner layer portion is formed of a plurality of FCCLs in which a coverlay is laminated through the above-described process, and an outer layer portion is formed by separately cut FCCL to lay up the inner layer portion and the outer layer portion Lay-Up, and then laminate them using the adhesive force of the interlaminar adhesive. These interlayer adhesives are cut after they have been cut to the required size and then removed by unnecessary parts by CNC machining or metal stamping.

However, such a conventional manufacturing method has a problem in that the multilayer flexible printed circuit board becomes thick as the use of the auxiliary material increases due to the complexity of the lamination process. Particularly, after the coverlay film and the interlayer adhesive are cut to the required panel size, the coverlay film and the interlayer adhesive are put into a subsequent process. However, this operation is complicated and the productivity is low and processing error is serious.

Korean Unexamined Patent Publication No. 2007-0019199 discloses a method of removing an unnecessary portion of a coverlay film and an interlayer adhesive by using a laser beam. However, since the flexible printed circuit board is not sufficiently thinned due to the trend of thinning and shortening There is a continuing need for a method of manufacturing a multilayer flexible printed circuit board suitable for forming a fine circuit

It is an object of the present invention to provide a multilayer printed circuit board lamination film in which a multilayered printed circuit board is thinned and an insulating adhesive is applied to the polyimide film surface of a sputter type single-sided FCCL to form a microcircuit.

It is another object of the present invention to provide a multilayer printed circuit board assembly comprising the multilayer printed circuit board lamination film.

It is still another object of the present invention to provide a method for manufacturing a multilayer printed circuit board in which the multilayer printed circuit board lamination film is sequentially attached and cured on an inner layer circuit to form an outer layer circuit.

In order to achieve the above object, the present invention provides a multilayer printed circuit board (FCCL) comprising a copper foil layer and a polyimide film, the multilayer printed circuit comprising an insulating adhesive layer formed by applying an insulating adhesive on the polyimide film side in a sputter- A film for substrate lamination is provided.

In the sputter-type single-sided flexible copper-clad laminate film (FCCL), the thickness of the copper foil layer is 0.1 to 50 탆, and the thickness of the polyimide film is 5 to 100 탆.

The insulating adhesive layer had a thickness of 5 to 50 占 퐉 and the insulating adhesive had a circuit thickness of 18 占 퐉 and a circuit line width of 50 占 퐉 (L / S = 50/50) And is a migration-resistant adhesive that maintains a resistance of 10 ⁷ or more for 1000 hours or more under a voltage of 100V.

The present invention provides a multilayer printed circuit board assembly fabricated including the multilayer printed circuit board lamination film.

The present invention also provides a method of manufacturing a semiconductor device, comprising: forming a circuit on a copper foil layer of an FCCL; Attaching an insulating adhesive layer of the multilayer printed circuit board lamination film to the circuit surface; Curing the multilayer printed circuit board lamination film by heating and press molding; And attaching a dry film to the copper foil layer of the cured multilayer printed circuit board laminating film to form a circuit.

Since the multilayer printed circuit board lamination film according to the present invention uses sputter-type FCCL, it is possible to adjust the circuit thickness to a sub-micrometer level, And flame retardancy, and is excellent in anti-migration, so that it is possible to manufacture a circuit board having excellent durability at the same time as forming a microcircuit.

Therefore, the multilayer printed circuit board manufactured by the build-up process using the film for laminating the multilayer printed circuit board of the present invention is advantageous for thinning and has an advantageous effect for forming a fine circuit. Particularly, in the multilayer printed circuit board lamination film, the circuit line width can be miniaturized by using the copper foil layer as the circuit surface in the sputter-type FCCL.

Further, according to the method for manufacturing a multilayer printed circuit board of the present invention, it is possible to reduce the number of laminated films such as a coverlay and a bonding sheet, simplify the manufacturing process, and further reduce the thickness of the multilayer printed circuit board.

1 is a cross-sectional schematic diagram of a multilayer printed circuit board lamination film of the present invention,
2 is a cross-sectional schematic diagram of a multilayer printed circuit board of the present invention,
3 is a graph showing a change in resistance of the adhesive composition used in the multilayer printed circuit board lamination film of the present invention and the conventional coverlay film according to evaluation of migration resistance,
4 is a result of observing dendrite formation according to migration evaluation of the adhesive composition used in the multilayer printed circuit board lamination film of the present invention and conventional coverlay film.

Hereinafter, the present invention will be described in detail.

The present invention relates to a multilayer printed circuit board laminating film (110) comprising an insulating adhesive layer formed by applying an insulating adhesive on a polyimide film side of a sputter-type one-sided flexible copper-clad laminate film (FCCL) comprising a copper foil layer and a polyimide film, .

1. Multilayer printed circuit board lamination film (110)

The multilayer printed circuit board lamination film of the present invention has a surface of a polyimide film of a sputter-type FCCL coated with an insulating adhesive.

The sputter-type FCCL is an FCCL in which a copper foil layer 11 is formed on a polyimide film 12 by sputtering and plating. When the copper foil layer is formed by sputtering and copper plating, it is possible to control the thickness of the copper foil layer to 1 micrometer (mu m) or less. Another production method of the FCCL is a casting method or a lamination method. However, since the polyimide film is formed on the copper foil layer, it is not preferable because the thickness of the copper foil layer is limited.

At this time, the thickness of the copper foil layer 11 of the FCCL is preferably 0.1 to 50 탆, more preferably 0.5 to 50 탆. If the thickness of the copper foil layer is less than 0.1 占 퐉, there is a fear that a circuit is formed in the circuit formation through plating. If the thickness is more than 50 占 퐉, the entire thickness of the printed circuit board is thinned.

The thickness of the polyimide film 12 of the FCCL is preferably 5 to 100 占 퐉. At this time, when the thickness of the polyimide film is less than 5 탆, the reliability of the process is low since the substrate film passing through the preprocessing and sputtering process is thin, and when the thickness exceeds 100 탆, the entire thickness of the printed circuit board is thinned.

For the same purpose as the present invention, it is impossible to reduce the thickness of the copper foil layer to 3 μm or less when the film for lamination is manufactured using FCCL manufactured by the casting method. Since the minimum thickness of the commercialized copper foil is not less than 3 占 퐉 and the roughness Rz of the commercial copper foil for a printed circuit board is generally 2 占 퐉 or more, it is difficult to manufacture a printed circuit board having fine wiring.

In general, when a circuit is formed through wet etching used in the production of a printed circuit board, the thicker the circuit, the wider the width of the wirable layer, and the more difficult it is to form fine wirings.

In the fabrication of semiconductor substrates such as BGA (Ball Grid Array) and FBGA (Flip-Chip Ball Grid Array), a finer circuit is usually formed through plating because of limitations of the wet etching method. In the case of a flexible printed circuit board, as circuit miniaturization progresses, there is a limit to miniaturization of the circuit through wet etching, and it is expected that miniaturization of the circuit through the plating method is inevitable. Generally, when a circuit is formed through plating, a photoresist film is pressed on a seed layer having a sub-micro thickness, and exposure and development are performed to form an electrolytic circuit guide. Electroplating is then performed to increase the thickness of the circuit to a desired level, to remove the circuit guide, and finally to remove the seed layer by etching to separate the circuit and the circuit. Since the circuit formation through plating is performed as described above, the thinner the seed layer is, the more advantageous it is to form a finer circuit.

In the case of the film for laminating according to the present invention, since a sputter-type FCCL fabricated by a sputtering method is used, a seed layer having a submicron thickness can be provided. Even if the thickness of the copper foil of the lamination film is thick, it is possible to lower the thickness of the seed layer by etching before entering the above-mentioned circuit formation. However, as a wet etching method of the printed circuit board, It is not only difficult to finely cut the wafer, but also has a problem that a process cost is incurred due to the addition of the etching process.

The insulating adhesive is not particularly limited, but preferably uses an adhesive excellent in anti-migration performance under high temperature, high voltage, and high humidity conditions so as to be advantageous for circuit miniaturization.

The insulating adhesive 13 may preferably include an epoxy resin. The epoxy resin is a thermosetting resin that is stable at high temperatures, has excellent adhesive strength, and has an excellent insulating property and chemical resistance.

In this case, the adhesive composition may further comprise a curing agent, a binder and a flame retardant. When the adhesive layer covers a circuit having a thickness of 18 μm and a line width of 50 μm (LS = 50/50) , And an excellent anti-migration capable of maintaining a resistance of 10 ⁷ Ω or more for 1000 hours or more under an applied voltage of 100V.

The thickness of the insulating adhesive layer is preferably 5 to 50 占 퐉. If the thickness is less than 5 占 퐉, the thickness of the adhesive layer is insufficient to cover the circuit pattern and the flowability of the adhesive is insufficient, If the thickness is more than 50 μm, the flexibility of the flexible printed circuit board is impaired, and there is a fear that the excess adhesive adheres to fill the circuit and contaminate the surface of the circuit board. That is, there is a problem of bleed-out.

In addition, a releasing paper or a releasing film may be laminated on the insulating adhesive layer to form the releasing member layer 14 to protect it. Any of the releasing paper and the release film may be used as long as it is normal, and preferably, a release layer containing a silicone coating layer can be used to facilitate peeling.

2. Multilayer printed circuit board manufacturing method

The present invention provides a multilayer printed circuit board assembly including the multilayer printed circuit board laminate film and a method of manufacturing the multilayer printed circuit board.

Specifically, the method includes forming a circuit on the copper foil layer of the FCCL 120; Attaching an insulating adhesive layer of the multilayer printed circuit board laminating film (110) to the circuit; Curing the multilayer printed circuit board lamination film by heating and press molding; And attaching a dry film to the copper foil layer of the cured multilayer printed circuit board lamination film to form a circuit.

The FCCL 120 is formed of a copper foil layer of a polyimide film layer, and any of commercially available films can be used. More preferably, a double-side FCCL is used.

A dry film is attached to the exposed copper foil layer of the FCCL, and an inner layer circuit is formed through exposure, etching, and development. The line width of the circuit and the method of forming the circuit may be those known in the art depending on the use of the circuit board.

The method for manufacturing a multilayer printed circuit board is characterized in that an adhesive layer of the multilayer printed circuit board lamination film is adhered and cured on the formed inner layer circuit to form an outer layer circuit. No other coverlay film or bonding sheet or the like is attached thereto.

The multilayer printed circuit board lamination film can be heated and pressed for attachment and curing, and preferably press molded at a temperature of from 140 to 160 DEG C and a pressure of from 2 to 7 MPa for 60 minutes.

After attaching a dry film on the exposed copper layers of both sides of the film for laminating the multilayer printed circuit board thus adhered, forming an outer layer circuit through exposure, etching and development, the cover layer film 130 are attached and cured to produce a multilayer printed circuit board. A multilayer printed circuit board lamination film may be additionally laminated as required before the coverlay film is attached.

Hereinafter, the present invention will be described in more detail with reference to Examples.

The present invention is intended to more specifically illustrate the present invention, and the scope of the present invention is not limited to these embodiments.

< Example  1> Multilayer Printed Circuit Board Lamination Film Production

(One) Selection of base FCCL

As the sputter-type FCCL, chromium-free FCCL produced by Toray Advanced Materials Co., Ltd. was selected. Specifically, a copper foil layer having a thickness of 12 탆 was formed on a 25 탆 thick polyimide film (100ENC, DuPont- Toray Co Ltd) Sputter and plated FCCL were used.

(2) Insulating adhesive composition

100 parts by weight of a dicyclopentadiene-based epoxy resin (XD-1000 epoxy equivalent of 253 g / eq, manufactured by Japan Chemical Industry Co., Ltd.) as an epoxy resin was added to 100 parts by weight of a dicyclopentadiene phenol resin (SD1806 epoxy reaction equivalent (Al (OH) 3) as a flame retardant, and 50 parts by weight of a phosphorus-based flame retardant (trade name, manufactured by Sumitomo Chemical Co., Ltd.) 50 parts by weight of a 1: 1 combination of Clariant, phosphinate OP-935) was added to a methyl ethyl ketone solvent, and the mixture was stirred at room temperature under normal pressure for 5 hours to obtain an adhesive composition having a solid content of 36 wt% Of varnish were prepared.

(3) Applying adhesive composition and protective film

The varnish of the insulative adhesive composition was coated on one surface of the sputtering type FCCL on which the polyimide was exposed at a thickness of 25 탆, dried in a convection oven at 130 캜 for 3 minutes, and transferred to a releasing paper (YC-3 ) Was laminated so as to adhere to the exposed one side of the applied insulating adhesive layer to prepare a multilayer printed circuit board lamination film. A cross-sectional schematic diagram of the multilayer printed circuit board lamination film manufactured as described above is shown in Fig.

< Example  2> Multilayer Printed Circuit Board Lamination Film Production

(One) Selection of base FCCL

As the sputter type FCCL, chromium-free FCCL produced by Toray Advanced Materials Co., Ltd. is selected. The FCCL is formed by sputtering and plating a copper foil layer having a thickness of 0.8 mu m on a 25 mu m thick polyimide film (100ENC, DuPont-Toray Co Ltd).

(2) Insulating adhesive composition

The varnish of the adhesive composition was prepared in the same manner as in the step (2) of Example 1 above.

(3) Applying adhesive composition and protective film

Was carried out in the same manner as in Example 1 to prepare a multilayer printed circuit board lamination film having an adhesive thickness of 25 mu m.

< Comparative Example  1>

80 parts by weight of nitrile-butadiene rubber (NBR), 4,4-diaminodiphenyl (meth) acrylate as an aromatic diamine curing agent, 100 parts by weight of a non-halogenated phosphorus epoxy resin (SEN320PM60, 4 parts by weight of sulfone, 0.4 part by weight of 2-ethyl-4-methyl imidazole (manufactured by Shikoku Chemicals) as a curing accelerator, and 5 parts by weight of an organic phosphorus flame retardant containing phosphorus of 17.5% by weight were added. The crude solution was coated on a polyimide film and dried at 130 ° C for 3 minutes to form a coverlay film having a thickness of 25 μm after coating.

< Experimental Example  1> Property evaluation

1. Adhesion

The multilayer printed circuit board lamination film of Example 1 and the coverlay film of Comparative Example 1 were pressed on a copper foil surface of FCCL (9D 2LTM55, manufactured by Toray Industries, Ltd.) at 160 캜 and 7 MPa for 60 minutes, And then peeled off at 90 ° using a universal testing machine (UTM). The adhesive strength was measured five times for each sample, and the average values are shown in Table 1 below.

2. Heat resistance

The multilayer printed circuit board lamination film of Example 1 and the coverlay film of Comparative Example 1 were pressed on a copper foil surface of FCCL (9D 2LTM55, manufactured by Toray Industries, Ltd.) at 160 ° C and 7 MPa for 60 minutes, And cut into a size of 20 mm x 20 mm. The prepared specimens were allowed to stand at 25 DEG C and 55% RH for 24 hours and then floated in a solder pot at 260 DEG C, 270 DEG C, and 280 DEG C for 1 minute. Subsequently, distortion and bubble formation on the surface of the film were confirmed as shown in Table 1 below.

○: No bubble formation or surface deformation (good)

Δ: No bubble formation, but surface deformation observed

X: Both bubble formation and surface deformation were observed (poor)

3. Flammability

The multilayer printed circuit board lamination film of Example 1 and the coverlay film of Comparative Example 1 were attached to both sides of a polyimide film (100ENC, DuPont-Toray Co Ltd) having a thickness of 25 mu m, The copper foil layer of the circuit board lamination film was removed by an etching method to prepare a flame retardancy evaluation sample. Each sample was cut into a width of 50 mm × length of 200 mm and flame retardancy was evaluated according to the standard of UL 94 VTM-0 as shown in Table 1.

Flammability When the VTM-0 standard is satisfied: ○ (Good)

Flammability When the VTM-0 standard is not satisfied: x (bad)

As shown in Table 1, the multilayer printed circuit board lamination film of Example 1 was superior in heat resistance and flame retardancy in comparison with the conventional coverlay film, and in particular, superior adhesion to Comparative Example 1 was confirmed.

< Example  3> Four-layer printed circuit board manufacture with multilayer printed circuit board lamination film

A dry film was adhered to the copper foil layer exposed on the double-sided FCCL (9D 2LTM55, manufactured by Toray Industries, Ltd.), exposed, etched and developed to form a copper circuit having two layers of circuit line width of 50 mu m (LS = 50/50 mu m) . Subsequently, two films for multilayer printed circuit board lamination prepared in Example 1 were used. After the respective protective films were removed, they were adhered to both sides of the copper circuit and cured. For the above attachment and curing, press molding was carried out at 160 캜 and 7 MPa for 60 minutes.

Subsequently, the dry film was adhered to the copper foil layers on the exposed both sides of the adhered and cured circuit stacking film, and then exposed, etched and developed to form a copper circuit having a circuit line width of 50 mu m (LS = 50/50 mu m). Finally, a cover-lay film (9X1N-00004S from Toray Advanced Materials Co., Ltd.) was attached to the exposed double-sided copper circuit and cured, thereby completing a printed circuit board having a four-layer circuit.

< Example  4> Multilayer Printed Circuit Board Fabrication of four-layer printed circuit board with film for lamination

A printed circuit board having a four-layer circuit was further completed by the same method as in Example 3, except that two films for multilayer printed circuit board lamination of Example 2 were used.

< Comparative Example  2> Bonding sheet  4-layer printed circuit board manufacturing

A dry film was attached on the exposed copper foil layer of the double-sided FCCL (9D 2LTM55, manufactured by Toray Industries, Ltd.), exposed, etched and developed to form a copper circuit having two layers of circuit line width 50 탆 (LS = 50/50 탆) . Then, the coverlay film of Comparative Example 1 was adhered to each of the exposed copper circuits of the formed FCCL and then cured to produce a printed circuit board having two layers of circuits.

One printed circuit board having two layers of circuits was manufactured in the same manner, and a bonding sheet (double-sided adhesive for printed circuit boards, manufactured by Toray Advanced Materials Co., Ltd., BSA-125 ) Were adhered and cured, so that two two-layer printed circuit boards were laminated together to complete a printed circuit board having four-layer circuits.

The manufacturing process and the thickness of the manufactured Example 3 and Comparative Example 2 are shown in Table 2 below.

As can be seen in Table 2 above, a total of two films are used less than conventional printed circuit board production using a bonding sheet, and a four-layer printed circuit board having a thinner thickness while reducing the number of times of lamination and pressing .

< Example  5>

The insulating adhesive composition prepared in Example 1 was coated on a polyimide film (50ENS, DuPont-Toray Co Ltd) having a thickness of 12.5 占 퐉 so as to have a thickness of 20 占 퐉 and dried in a convection oven at 130 占 폚 for 3 minutes. Then, the insulating adhesive surface coated on the polyimide film was laminated to cover the remainder of the copper circuit of the HAST (Highly Accelerated Stress Test) except for the electrode ground portion. The laminate was press molded at a temperature of 160 DEG C and a pressure of 7 MPa for 60 minutes.

< Comparative Example  3>

The coverlay film produced by the same method as in Comparative Example 1 except that the adhesive composition was applied on the polyimide film in a thickness of 20 mu m was coated on the adhesive surface in a highly accelerated stress test (HAST) The copper circuit of the coupon was attached and covered so as to cover the rest except for the electrode ground portion. The laminate was press molded at a temperature of 160 DEG C and a pressure of 7 MPa for 60 minutes.

< Experimental Example  2> My migration (anti-migration) evaluation

The specimens of Example 5 and Comparative Example 3 were subjected to a voltage of 100 V at 85 ° C and 85% RH, respectively, and the resistance was recorded for 1000 hours. The results are shown in FIG. 3 and FIG.

FIG. 3 shows resistance changes over time for the specimens of Example 5 and Comparative Example 3. In Example 5, the resistance of 10 ⁷ Ω or more was maintained for 1000 hours while Comparative Example 3 showed a resistance A descent was observed.

4 shows a result of observing the circuit portion of the sample after high-voltage insulation reliability evaluation by a microscope. In the case of the test piece of Comparative Example 3, it was confirmed that a dendrite reached the opposite electrode and a short circuit occurred (right) Clean electrode surfaces were observed and found to be free of copper elution and dentrite formation (left).

11: copper foil layer 12: polyimide film
13: Insulating adhesive layer 14: Release protective layer
110: Multilayer printed circuit board lamination film
120: Double-sided FCCL 130: Coverlay film

Claims (7)

And an insulating adhesive layer formed by applying an insulating adhesive on the surface of the polyimide film in a sputter-type one-sided flexible copper-clad laminate film (FCCL) comprising a copper foil layer and a polyimide film. The multilayer printed circuit board lamination film according to claim 1, wherein the thickness of the copper foil layer is 0.1 to 50 탆. The multilayer printed circuit board lamination film according to claim 1, wherein the thickness of the polyimide film is 5 to 100 占 퐉. The multilayer printed circuit board lamination film according to claim 1, wherein the insulating adhesive layer has a thickness of 5 to 50 mu m. The insulating adhesive according to claim 1, wherein the insulating adhesive has a circuit thickness of 18 占 퐉 and a circuit line width of 50 占 퐉 (L / S = 50/50) Wherein the adhesive is a migration resistant adhesive that maintains a resistance of ⁷ or more. A multilayer printed circuit board assembly fabricated by including the multilayer printed circuit board lamination film of claim 1. Forming a circuit on the copper foil layer of the FCCL;
Attaching an insulating adhesive layer of the multilayer printed circuit board lamination film of claim 1 to the circuit surface;
Curing the multilayer printed circuit board lamination film by heating and press molding; And
And forming a circuit on the copper foil layer of the cured multilayer printed circuit board laminating film.

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