Narrow-trace silver flexible circuits; Ag-ink technology, on PET

November 30, 2016 // By Graham Prophet
Molex has developed the capability to print high-performing silver flexible circuits on economical polyester substrates with traces and spacing as narrow as 0.13 mm (.005 in.). The process is presented as a viable, cost-effective alternative to traditional flexible circuits [of] etched copper traces on polyimide and PCBs. Molex has also developed a method to overcome restrictions on attaching fine-pitch, IC based components on PET, and offers the system as compatible with standard SMT processes.

“Designers must fit ever-smaller components and traces on limited real estate,” said Dan Dawiedczyk, director of marketing, Molex. “Polyimide can accommodate that need, but is more expensive than PET. As an alternative to copper circuits, Molex has the option to use new silver ink technology and advanced printing to screen extremely fine traces on PET in a wide variety of applications.” Dawiedczyk noted that in addition to reducing costs by applying silver traces to PET, those traces are inherently less expensive than copper etching and associated processing. Additionally, the manufacturing of the Silver Flexible Circuits does not require harsh chemicals or a waste treatment facility.


The technology allows the attachment of fine-pitch (0.50 mm) IC based components on PET via a proprietary bonding process using traditional SMT equipment. That process also enables attachment of right angle LEDs, enabling enhanced backlighting for user-interface applications. In the final step of the attachment process, a UV-cured encapsulant is used to protect the solder joints, making it possible for them to withstand vibration and mechanical shock.