| abstract |
This invention provides a circuit board for preventing degradation in the reliability and the performance of an electronic part such as a mounted IC chip. In an FPC substrate 400, copper foil bonded to both faces of a base film 410 having insulating property and flexibility without a bonding layer is patterned, and an input wiring 420a and an output wiring 420b are formed on the mounting face of an electronic part and a dummy wiring layer 422 on a face opposite to the mounting face. The dummy wiring layer 422 is installed to be slightly wider than an area where an IC chip 450 is mounted and it has moisture proof and light shielding features. The input electrode 450a and the output electrode 450b of the IC chip 450 are electrically connected to the input wiring 420a and the output wiring 420b, respectively, through conductive particles 460a dispersed in the adhesive 460 of epoxy resin and the like at an appropriate rate, and they are sealed by adhesive 460. |