Roll-to-roll manufacturing of dense copper traces on long flexible and stretchable foil stripes
To produce cables of 1 meter or longer, we utilize our pilot line of roll-to-roll technology developed at Fraunhofer EMFT. The approach, combined with specialized R2R processes and machinery, enables the precise creation of metal patterns on flexible and stretchable substrates. A key component of this fabrication is the integration of a unique digital lithography stitching technique, which allows to produce high-quality, durable cables at extended lengths.
The fabrication of the long cable consists of metal deposition on a flexible substrate, followed by lithography and etching (for Cu thickness up to 500 nm), or electroplating (for Cu thickness of 5-10µm). The semi-additive electroplating process enhances sustainability in metal patterning on flexible substrates by significantly reducing metal waste. In this process, metal thickness is selectively increased through electroplating, requiring only a thin seed layer, typically in the nanometre range, to be etched away. This contrasts with traditional methods, where thick metal layers—often several microns—are etched, generating substantial metal waste. By minimizing etching, the semi-additive process reduces both material consumption and chemical waste, making it a more environmentally friendly and resource-efficient alternative.
