Advanced Circuit Board Technologies

Yoshitaka Fukuoka of Weisti chaired the CPMT Seminar on Thursday, June 2 evening. Five excellent detailed presentations were made on next generation flex circuit capability. Attendance exceeded 80 despite the excellent food and drinks in the overlapping reception.

Masahiko Takeuchi of Nippon Steel Chemical Co. discussed the details of the ESPANEX series M and L. Cost is kept low by using roll to roll manufacturing. The uptake of moisture is very low and thus the dimensional changes are small. The dielectric constant of the LCP film is 2.8, the dissipation factor is .0025, and the M-series is good to 25 GHz and L-series is good to 37 GHz. Via holes of 50 micron are possible.

Yasuhito Oowaki of Nitto Denko Corporation discussed Ultra-thin Flex. By using photosensitive polyimide they demonstrated 3 orders of magnitude more flex cycles than past flex materials.

Yoshihisa Katoh of CMK Corporation discussed Rigid-Flexible Circuit Board developments. The ability to let the flex provide connection rather than connectors allows designers to save much volume in consumer electronics. In addition, the resistance for a connection is often x10 lower. The advances are being pushed by the automotive applications which demand 3200 cycles from -30 to +110 C.

Masaaki Katsumata of Panasonic Electronic Devices discussed the IVH Structure substrate. Of particular interest was their use of silver coated copper particles in a past to fill laser vias. The resistance of these vias showed no change in aging experiments.

Koichiro Nakase of NEC Corporation discussed thin-film embedded passives concentrating on the 1 GHz range. He showed many techniques to achieve high self-resonance frequencies, well above those of circuit operation.