ELECTROMAGNETIC WAVE SHIELD FILM, PRINTED WIRING BOARD USING SAME, AND ROLLED COPPER FOIL
An electromagnetic wave shield film in which peeling off between a metal thin film and an adhesive layer is prevented and a printed wiring board employing the electromagnetic wave shield are provided. An electromagnetic wave shield film is formed by laminating at least a metal thin film and an adhesive layer in order, and the water vapor permeability of the electromagnetic wave shield film according to JISK7129 is 0.5 g/m 2 per 24 hours or higher at a temperature of 80 degrees centigrade, a moisture of 95% RH, and a pressure difference of 1 atm.
1 . An electromagnetic wave shield film comprising at least a metal thin film and an adhesive layer, the metal thin film and the adhesive later being laminated in order, wherein, water vapor permeability according to JISK7129 is 0.5 g/m 2 per 24 hours or higher at a temperature of 80 degrees centigrade, a moisture of 95% RH, and a differential pressure of 1 atm.
2 . The electromagnetic wave shield film according to claim 1 , wherein,
the metal thin film is formed by impregnating, into a solvent, a metal sheet which is formed of a hard-to-melt component with low solubility in the solvent and an easily-melted component more soluble in the solvent than the hard-to-melt component,
the easily-melted component is particles of a granular material dispersed in the metal sheet, and
as the granular material is dissolved in the solvent, openings are formed in the metal thin film.
3 . The electromagnetic wave shield film according to claim 2 , wherein, the hard-to-melt component is metal mainly made of copper, whereas the easily-melted component is copper oxide.
4 . The electromagnetic wave shield film according to claim 2 , wherein, the hard-to-melt component is metal mainly made of copper, whereas the easily-melted component is copper oxide (I).
5 . The electromagnetic wave shield film according to claim 2 , wherein, each of the openings is in a range of 0.1 to 100 μm in diameter.
6 . The electromagnetic wave shield film according to claim 2 , wherein, the number of the openings per 1 cm 2 in the metal thin film is 10 to 1000/cm 2 .
7 . The electromagnetic wave shield film according to claim 2 , wherein, the metal thin film is in a range of 0.5 to 12 μm in thickness.
8 . The electromagnetic wave shield film according to claim 1 , wherein, the metal thin film is a rolled copper foil.
9 . A rolled copper foil in which openings are formed by wet etching, wherein, each of the openings is in a range of 0.1 to 100 μm in diameter, the number of the openings per 1 cm 2 in the rolled copper foil is in a range of 10 to 1000/cm 2 , and the rolled copper foil is in a range of 0.5 to 12 μm in thickness.
10 . A shield printed wiring board comprising the electromagnetic wave shield film according to claim 1 .