Abstract: An insulation film of a signal transmission line includes a substrate layer, and a bonding layer arranged on the substrate layer for directly covering metal conductors of the signal transmission line, wherein the bonding layer is made of a polyolefin copolymer resin or a polyolefin resin mixture.

Abstract: A cover layer of a printed circuit board has a polymer film, a reflective composite layer and an adhesive layer. The polymer film has a melting point greater than 260° C. The reflective composite layer is mounted on one side surface of the polymer film and has a first reflective pigment. The adhesive layer is mounted on another side surface of the polymer film. Also, at a range of wavelength where a reflectivity of the cover layer is greater than 89%, absorption of the polymer film to the same range of wavelength is less than 35%. The cover layer is laminated on a printed circuit board and after surface mount technology process at a temperature ranging from 160° C. to 320° C., the cover layer has a reflectivity over 89% without yellowing and delamination.

Abstract: A method for manufacturing a low thermal-impedance insulated metal substrate has steps of providing an electrical-conductive metal layer; forming a first thermal-conductive polymeric composite layer on the electrical-conductive metal layer; forming a second thermal-conductive polymeric composite layer on the first thermal-conductive polymeric composite layer; and adhere a thermal-conductive metal layer on the second thermal-conductive polymeric composite layer by hot-pressing process. Therefore, the low thermal-impedance insulated metal substrate of the present invention has lower thermal-impedance, lower coefficient of thermal expansion and higher electrical reliability.

Abstract: A method for manufacturing a low thermal-impedance insulated metal substrate has steps of providing an electrical-conductive metal layer; forming a first thermal-conductive polymeric composite layer on the electrical-conductive metal layer; forming a second thermal-conductive polymeric composite layer on the first thermal-conductive polymeric composite layer; and adhere a thermal-conductive metal layer on the second thermal-conductive polymeric composite layer by hot-pressing process. Therefore, the low thermal-impedance insulated metal substrate of the present invention has lower thermal-impedance, lower coefficient of thermal expansion and higher electrical reliability.