Abstract: A preferably low dielectric constant polymeric bonding layer is applied or bonded (i.e., laminated or coated) to at least one side of a preferably low dielectric constant polymeric delay line substrate. Preferably, the melting or softening point of the bonding film is lower than the melting or softening point of the substrate so that the application (e.g. lamination) step is carried out at a temperature which is above the softening point of the bonding film, but below the softening point of the substrate (thereby insuring the integrity of the delay line circuit). Thereafter, the delay line/bonding layer assembly is rolled up and head sealed so as to melt the bonding layer, thus heat sealing the delay line package. As the package heats up (in, for example, a tightly fitting die), the materials expand and provide sufficient pressure to bond the circuit together.

Abstract: Inductive devices, i.e., transformers, coils, inductors, etc. are produced from a rolled flexible circuit. The flexible circuit is comprised of a dielectric substrate having a circuit pattern thereon. The circuit pattern is configured such that, upon rolling, one or more coils is formed thereby defining an inductor, transformer, etc. Additionally, these inductive devices may be easily shielded using a ground plane in the flexible circuit. The rolled flexible circuit may be secured in several ways including an adhesive or by using a thermoplastic bonding layer which acts to heat seal the circuit together. The inductive devices of the present invention may be wrapped or rolled about a permeable core which improves inductance. Inductor devices manufactured in accordance with the present invention have the advantages of being small, surface mountable, inexpensive to manufacture and being capable of insertion onto printed wiring boards using automated insertion equipment.

Abstract: A flexible circuit laminate is presented comprising a microglass reinforced fluoropolymer layer sandwiched between a polyimide substrate and a copper conductive pattern. The glass reinforced fluoropolymer acts as a high bond strength adhesive between the polyimide and copper conductive pattern. The glass reinforced fluoropolymer also contributes to improved dimensional stability as well as improved electrical performance. Preferably, the microglass content is between about 4 to about 30 weight percent, and more preferably about 20 weight percent glass. In a method of making the flexible circuit laminate, the polyimide substrate undergoes a preferably alkaline microetching surface treatment, followed by rinsing, drying and lamination to the microglass reinforced fluoropolymer and copper layers.