| 摘要 |
PURPOSE:To stabilize the quality of the title circuit board by using a specific animal film for a flexible insulating film which becomes a substrate film and another flexible insulating film for cover-lay and, at the same time, setting the level difference between the etched-off section and remaining section of copper foil on the circuit forming surface of a flexible circuit board at a prescribed value or smaller. CONSTITUTION:By using a film which has a tensile strength of <=0.7kg/cm) width when the film is elongated by 0.5% in a 100 deg.C atmosphere and a thermal shrinkage factor of <=0.05% after the film is heat-treated for 30 minutes at 150 deg.C for a flexible insulating film which becomes the substrate film 17 of a flexible circuit board 10 and another flexible insulating film 13 for covering, a flexible circuit board 10 the circuit forming surface 11 of which is coated with the film 13 is manufactured. The maximum value of the level difference X between the etched-off section and remaining section 19 of copper foil on the surface 11 is controlled to 18mum. Therefore, the quality of the flexible circuit board can be stabilized. |
