Flexible Electronics Printing by Electroplating

Abstract

In many electronics ' industrial applications deposition of metal on isolated electronic structures is necessary to deliver functional products. Examples are Flexible Electronics, PWB surface finishing and IC manufacturing. The typical state-of-the-art approach by the industry is to apply electroless or immersion processing or, by application of metal containing pastes, both burdened with inherent problems. Flexible Electronics, having no common current collector, are predominantly produced by inkjet or screen printing of metal and carbon pastes over a flexible substrate. Having inferior conductivity compared to pure metals to achieve adequate performance, the pastes are significantly thicker and bulkier than the pure metal. It is desirable to have an efficient way for electroplating patterned isolated electronic structures, if possible without the seed layer. This calls for establishing electrical contacts with all isolated structures without interfering with the electric field access to all structures that need electroplating. Contact Electroplating Technology (CET), US Patent #10,184,189 [17], has been demonstrated with isolated patterned structures of various substrates including Flexible Electronics. Following a high-speed xeroxing or patterning of isolated electronic structures with a layer of negligible thickness and resistance as high as several kiloohms cm, the Electrochemical Printing Technology (EPT) enables upgrading of the same by deposition of pure metal of desired thickness up to 10 microns. Completely isolated electronic interconnects with spacing as low as 25 microns were uniformly electroplated within seconds with Ag, Cu, Ni and Au.