FLEXIBLE METAL LAMINATE CONTAINING FLUOROPOLYMER

• US 20130065018A1
• Filed: 09/06/2012
• Published: 03/14/2013
• Est. Priority Date: 09/07/2011
• Status: Active Grant

• Current Assignee: Shengyi Technology Co., Ltd.
• Original Assignee: LG Chem Limited (LG Corporation)
• Inventors: PARK, Young-Seok, PARK, Soon-Yong, JANG, Se-Myung
• Granted Patent: US 9,462,688 B2
• Time in Patent Office: Days
• US Class Current: 428/141
• CPC Class Codes: B32B 2037/243 Coating
• CPC Class Codes: B32B 2255/06 on metal layer
• CPC Class Codes: B32B 2255/26 Polymeric coating
• CPC Class Codes: B32B 2255/28 Multiple coating on one surface
• CPC Class Codes: B32B 2311/00 Metals, their alloys or their compounds
• CPC Class Codes: B32B 2327/12 containing fluorine
• CPC Class Codes: B32B 2379/08 Polyimides
• CPC Class Codes: H05K 1/024 Dielectric details, e.g. changing the dielectric material around a transmission line
• CPC Class Codes: H05K 1/036 Multilayers with layers of different types
• CPC Class Codes: H05K 1/0393 Flexible materials H05K1/038 takes precedence; specific organic compositions are classified in H05K1/0313 and subgroups
• CPC Class Codes: H05K 3/022 Processes for manufacturing precursors of printed circuits, i.e. copper-clad substrates
• CPC Class Codes: Y10T 428/24355 Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]
• CPC Class Codes: Y10T 428/24975 No layer or component greater than 5 mils thick
• CPC Class Codes: Y10T 428/264 Up to 3 mils
• CPC Class Codes: Y10T 428/3154 Of fluorinated addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/31544 Addition polymer is perhalogenated
• CPC Class Codes: Y10T 428/31681 Next to polyester, polyamide or polyimide [e.g., alkyd, glue, or nylon, etc.]
• CPC Class Codes: Y10T 428/31721 Of polyimide

Abstract

The present invention relates to a flexible metal laminate with low dielectric constant, which may be applied for a substrate for a flexible printed circuit. A flexible metal laminate according to one aspect of the invention includes a first metal layer; a first polyimide layer; a polyimide layer including fluoropolymer dispersed therein, formed on the first polyimide layer; and a second polyimide layer formed on the polyimide layer including fluoropolymer dispersed therein; wherein in the polyimider layer including dispersed fluoropolymer, the content of the fluoropolymer per unit volume is higher at 40 to 60% depth than at 5 to 10% depth of the total thickness from the surface of the polyimide layer.

Claims

1. A flexible metal laminate comprising

a first metal layer;

a first polyimide layer;

a polyimide layer including fluoropolymer dispersed therein, formed on the first polyimide layer; and

a second polyimide layer formed on the polyimide layer including fluoropolymer dispersed therein;

wherein in the polyimide layer including dispersed fluoropolymer, the content of the fluoropolymer per unit volume is higher at 40 to 60% depth than at 5 to 10% depth of the total thickness from the surface of the polyimide layer.

2. The flexible metal laminate according to claim 1, wherein the polyimide layer including dispersed fluoropolymer has the lowest content of the fluoropolymer per unit volume at 5 to 10% depth of the total thickness from the surface of the polyimide layer.

3. The flexible metal laminate according to claim 1, wherein the polyimide layer including dispersed fluoropolymer has the highest content of the fluoropolymer per unit volume at 40 to 60% depth of the total thickness from the surface of the polyimide layer.

4. The flexible metal laminate according to claim 1, wherein in the polyimide layer including dispersed fluoropolymer, the content of the fluoropolymer per unit volume gradually increases with depth, at 5 to 15% depth of the total thickness from the surface of the polyimide layer.

5. The flexible metal laminate according to claim 1, further comprising a second metal layer formed on the second polyimide layer.

6. The flexible metal laminate according to claim 1, wherein the surface of the first metal layer and the surface of the second surface layer respectively have ten point average roughness (Rz) of 0.5 to 2.5 um.

7. The flexible metal laminate according to claim 1, wherein the first polyimide layer and the second polyimide layer respectively have a thickness of 1 to 10 um.

8. The flexible metal laminate according to claim 1, wherein the polyimide layer including dispersed fluoropolymer has a thickness of 5 to 50 um.

9. The flexible metal laminate according to claim 1, wherein the fluoropolymer is at least one selected from the group consisting of polytetrafluoroethylene (PTEF), perfluoroalkoxy (PFA), fluorinated ethylene propylene (FEP), chlorotrifluoroethylene (CTFE), tetrafluoroethylene/chlorotrifluoroethylene (TFE/CTFE), ethylene chlorotrifuloroethylene (ECTFE), and polyfluorinated vinylidene (PVDF).

10. The flexible metal laminate according to claim 1, wherein the fluoropolymer is included in the content of 10 to 60 wt % in the polyimide layer including dispersed fluoropolymer.

11. The flexible metal laminate according to claim 1, wherein the polyimide layers including the first polyimide layer, the polyimide layer including dispersed fluoropolymer, and the second polyimide layer have dielectric constant of 2.2 to 3.2 at 1 MHz, dielectric loss of 0.001 to 0.007, and thermal expansion coefficient of to 15 to 35 ppm.

12. The flexible metal laminate according to claim 1, wherein the first metal layer and the second metal layer are thin films of one selected from the group consisting of copper, iron, nickel, titanium, aluminum, silver and gold, or an alloy of two or more kinds thereof.

13. A method for manufacturing a flexible metal laminate comprising:

coating a first polyamic acid varnish on a first metal layer;

coating polyamic acid varnish including fluoropolymer powder dispersed therein on the first polyamic acid varnish; and

coating a second polyamic acid varnish on the polyamic acid varnish including fluoropolymer powder dispersed therein, drying and curing it.

14. The method according to claim 13, further comprising laminating a second metal layer on a polyimide layer formed by curing the second polyamic acid varnish.

15. The method according to claim 13, wherein the first polyamic acid varnish and the second polyamic acid varnish are formed by reacting aromatic tetracarboxylic anhydride, and aromatic diamine under an organic solvent.

16. The method according to claim 15, the aromatic tetracarboxylic anhydride is at least one selected from the group consisting of pyromellitic dianhydride (PMDA), biphenyl-tetracarboxylic acid dianhydride (BPDA), 4,4′

-Benzophenonetetracarboxylic Dianhydride (BTDA), 4,4′

-Oxydiphthalic anhydride (ODPA), 4,4′

-(Hexafluoroisopropylidene)diphthalic Anhydride (6FDA), and 4,4′

-(4,4′

-isopropylidene-diphenoxy) bis(phthalic anhydride) (BPADA).

17. The method according to claim 15, the aromatic tetracarboxylic anhydride is included in the equivalents of 0.90 to 1.10 of the aromatic diamine.

18. The method according to claim 15, the aromatic diamine is at least one selected from the group consisting of phenylenediamine(PDA), oxydianiline (ODA), o-phenylenediamine (OPD), Meta phenylene Diamine (MPD), 1,3-bis(4-aminophenoxy) benzene(TPER), 4,4′

-bis(4-aminophenoxy)benzene (TPEQ), 2,2′

-Dimethyl-4,4′

-diamino biphenyl (m-TB-HG), 2,2′

-Bis(Trifluoromethyl) benzidine (TFDB), 1,3′

-Bis(3-aminophenoxy)benzene (APBN), 3,5-Diaminobenzotrifluoride(DABTF), and 2,2-bis(4-[4-aminophenoxy]-phenyl)propane(BAPP).

19. The method according to claim 15, the organic solvent is at least one selected from the group consisting of N,N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, N,N-dimethylmethoxyacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 1,3-dimethyl-2-imidazolidone, 1,2-dimethoxyethane, 1,3-dioxane, 1,4-dioxane, pyridine, picoline, dimethylsulfoxide, dimethylsulfone, m-cresol, p-chlorophenol, and anisole

20. The method according to claim 15, the organic solvent is included in the content of 70 to 90 wt %, based on the total weight of the polyamic acid varnish.

21. The method according to claim 13, wherein the polyamic acid varnish including fluoropolymer powder dispersed therein is prepared by dispersing fluoropolymer powder in an organic solvent using a polyester-based dispersant, and then, adding a mixture including aromatic tetracarboxylic anhydride and aromatic diamine, and agitating it.

22. The method according to claim 13, wherein the fluoropolymer powder has average particle diameter of 0.1 to 10.0 um.

23. The method according to claim 13, wherein the drying is conducted at 100 to 200°

C.

24. The method according to claim 13, wherein the curing is conducted at 300 to 400°

C. for 5 to 30 minutes.

25. The method according to claim 14, wherein the laminating of the second metal layer is conducted at 300 to 400°

C.

26. The method according to claim 13, wherein the first metal layer and the second metal layer are thin films of one selected from the group consisting of copper, iron, nickel, titanium, aluminum, silver and gold, or an alloy of two or more kinds thereof.