| 摘要 |
PURPOSE:To improve signals in transmission speed between a mounting IC chip and a carrier by a method wherein at least a part of a base film is formed of porous resin sheet. CONSTITUTION:A PTFE(porous polytetrafluoroethylene) sheet 9 is provided under a conductor 1 through the intermediary of a fluorine adhesive layer 2. By this setup, not only the positional deviation of an inner and an outer lead, 5 and 6, can be prevented but also the film carrier 1 can be decreased in transmission delay of signals owing to the sheet 9 of excellent dielectric characteristic (epsilonr=1.2). As the sheet 9 is very flexible, it is also conducive to the relaxation of thermal stress induced due to the linear expansion coefficient difference between the conductor 1 and a base film. |
