Fluororesin base material, printed wiring board, and circuit module

Patent metadata

Field	Value
Publication number	US-11364714-B2
Application number	US-201415027323-A
Country	US
Kind code	B2
Filing date	Oct 8, 2014
Priority date	Oct 11, 2013
Publication date	Jun 21, 2022
Grant date	Jun 21, 2022

Abstract

A fluororesin base material containing a fluororesin as a main component includes a modified layer on at least a partial region of a surface thereof, the modified layer containing a siloxane bond and a hydrophilic organofunctional group, and a surface of the modified layer having a contact angle of 90° or less with pure water.

First claim

The invention claimed is:

1. A printed wiring board comprising a fluororesin base material and a metal layer,
the fluororesin base material containing a fluororesin layer and a modified layer,
the metal layer being disposed on the modified layer,
the fluororesin layer containing a fluororesin as a main component,
a content of the fluororesin in the fluororesin base material being 90 mass % or more based on a total mass of the fluororesin base material,
the fluororesin containing a tetrafluoroethylene-hexafluoropropylene copolymer,
the modified layer being disposed on a partial region of a surface of the fluororesin layer in the fluororesin base material,
the modified layer containing a siloxane bond and a hydrophilic organofunctional group,
a surface of the modified layer having a contact angle of 90° or less with pure water,
the surface of the fluororesin layer not having the modified layer having a contact angle of 95° to 130° with pure water, wherein
a C atom in radical form of the fluororesin is covalently bonded to the siloxane bond (Si—O—Si) formed with a silane coupling agent via another atom or atomic group,
the fluororesin base material has an optical transmittance of 50% or more at a wavelength of 600 nm, and
the surface of the modified layer has a mean surface roughness Ra of 4 μm or less.

2. The printed wiring board according to claim 1 , wherein
a peel strength of an epoxy resin adhesive having an average thickness of 25 μm against the surface of the modified layer is 1.0 N/cm or more, as measured using a cover lay having a lamination of a polyimide sheet and the epoxy resin adhesive, the polyimide sheet having an average thickness of 12.5 μm.

3. The printed wiring board according to claim 1 , wherein
the modified layer is not removed by an etching treatment in which the modified layer is immersed under conditions of 45° C. and 2 minutes, using an etchant containing iron chloride and having a specific gravity of 1.33 g/cm 3 and a free hydrochloric acid concentration of 0.2 mol/L.

4. The printed wiring board according to claim 1 , wherein
the modified layer has an average thickness of 400 nm or less.

5. The printed wiring board according to claim 1 , wherein
the hydrophilic organofunctional group is a hydroxy group, a carboxy group, a carbonyl group, an amino group, an amide group, a sulfide group, a sulfonyl group, a sulfo group, a sulfonyldioxy group, an epoxy group, a methacryl group, a mercapto group, or a combination thereof.

6. The printed wiring board according to claim 1 , wherein
the metal layer is a conductive pattern.

7. The printed wiring board according to claim 1 , wherein
the printed wiring board includes a coating material laminated on the surface of the modified layer of the fluororesin base material.

8. The printed wiring board according to claim 1 , wherein
the surface of the modified layer has a mean surface roughness Ra of 1 μm or less.

9. A circuit module comprising the printed wiring board according to claim 1 .

10. A printed wiring board comprising a fluororesin base material and a metal layer,
the fluororesin base material containing a fluororesin layer and a modified layer,
the metal layer being disposed on the modified layer,
the fluororesin layer containing a fluororesin as a main component,
a content of the fluororesin in the fluororesin base material being 90 mass % or more based on a total mass of the fluororesin base material,
the modified layer being disposed on a partial region of a surface of the fluororesin layer in the fluororesin base material,
the modified layer containing a siloxane bond and a hydrophilic organofunctional group,
a surface of the modified layer having a contact angle of 90° or less with pure water,
a C atom in radical form of the fluororesin is covalently bonded to the siloxane bond (Si—O—Si) formed with a silane coupling agent via another atom or atomic group,
the fluororesin base material has an optical transmittance of 50% or more at a wavelength of 600 nm, and
the surface of the modified layer has a mean surface roughness Ra of 4 μm or less.

11. The printed wiring board according to claim 10 , wherein
a peel strength of an epoxy resin adhesive having an average thickness of 25 μm against the surface of the modified layer is 1.0 N/cm or more, as measured using a cover lay having a lamination of a polyimide sheet and the epoxy resin adhesive, the polyimide sheet having an average thickness of 12.5 μm.

12. The printed wiring board according to claim 10 , wherein
the modified layer is not removed by an etching treatment in which the modified layer is immersed under conditions of 45° C. and 2 minutes, using an etchant containing iron chloride and having a specific gravity of 1.33 g/cm 3 and a free hydrochloric acid concentration of 0.2 mol/L.

13. The printed wiring board according to claim 10 , wherein
the modified layer has an average thickness of 400 nm or less.

14. The printed wiring board according to claim 10 , wherein
the hydrophilic organofunctional group is a hydroxy group, a carboxy group, a carbonyl group, an amino group, an amide group, a sulfide group, a sulfonyl group, a sulfo group, a sulfonyldioxy group, an epoxy group, a methacryl group, a mercapto group, or a combination thereof.

15. The printed wiring board according to claim 10 , wherein
the metal layer is a conductive pattern.

16. The printed wiring board according to claim 10 , wherein
the printed wiring board includes a coating material laminated on the surface of the modified layer of the fluororesin base material.

17. The printed wiring board according to claim 10 , wherein
the surface of the modified layer has a mean surface roughness Ra of 1 μm or less.

Assignees

• Sumitomo Electric Printed Circuits Inc
• Sumitomo Electric Industries

Inventors

• KIYA Satoshi
• Uehara Sumito
• Miura Kousuke
• Nakabayashi Makoto

Classifications

• H05K2201/0326

  Inorganic, non-metallic conductor, e.g. indium-tin oxide [ITO] · CPC title

• H05K2201/09781

  Dummy conductors, i.e. not used for normal transport of current; Dummy electrodes of components · CPC title

• H05K1/0366

  reinforced, e.g. by fibres, fabrics (H05K1/036 takes precedence) · CPC title

• H05K2201/015

  Fluoropolymer, e.g. polytetrafluoroethylene [PTFE] · CPC title

• H05K3/20

  by affixing prefabricated conductor pattern {(H05K1/187, H05K3/046, H05K3/4658, H05K3/4682 takes precedence)} · CPC title