| 摘要 |
PROBLEM TO BE SOLVED: To provide a coverlay film having a good bonding strength with an FPC substrate material such as a polyimide film, showing good electric properties in an RF region of frequencies 1-10 GHz, specifically showing a low dielectric constant (&egr;) and a low dissipation factor (tanδ) in a region of frequencies 1-10 GHz and in addition, having plating resistance, and arranged so as to suppress the occurrence of curl at the time of thermal curing.SOLUTION: The coverlay film comprises: an organic film; and an adhesion layer formed on one side of the organic film. The adhesion layer includes (A)a vinyl compound expressed by the general formula (1) below, (B)a polystyrene-poly(ethylene/butylene)block copolymer, (C)a polystyrene-poly(ethylene-ethylene/propylene)block copolymer, (D)an epoxy resin, and (E)bismaleimide, provided that mass ratios of the components satisfy the conditions of (A+E)/(B+C)=0.81-1.00, and (B)/(C)=1.00-4.00, and the component (D) accounts for 1-10 mass% to the total mass of the components (A) to (E). The organic film has a melting point higher than a thermosetting temperature of the adhesion layer and has, in a region of frequencies 1-10 GHz, a dielectric constant (&egr;) of 4.0 or less, and a dissipation factor (tanδ) of 0.02 or less. |
