UV nanosecond laser precision etching on copper-clad polyimide for flexible thin film antenna pattern

This study investigates the precision processing of flexible thin film conformal antennas for use in aerospace and microelectronics applications. Current methods for processing these types of antennas have different degrees of defects, but the use of a UV-nanosecond laser offers several advantages, such as high photon energy, non-contact processing, and a small heat-affected zone. In this study, we conducted a technical analysis of the circuit structure of radar flexible thin film antennas through UV-nanosecond laser direct writing and achieved controlled processing of large-format radar flexible thin film conformal antennas. We built a UV-nanosecond laser processing system platform and carried out studies on both the single-line removal process and small-format fine removal. The surface roughness of polyimide was successfully reduced to 0.55 μm, the contour accuracy was controlled to within 10 μm, and high-quality processing of complex patterns was achieved. Based on these findings, the large-format flexible thin-film antenna stitching process was further investigated, and the contour error of large-format flexible thin-film antennas was successfully controlled within ± 8 μm, the stitching error within 2 μm, and the surface roughness within 0.24 μm. Furthermore, effective copper removal was achieved in the designed non-conductive regions. Ultimately, the proposed processing method enables the fabrication of large-format flexible film antennas with low surface roughness, good surface consistency, and no obvious stitching marks.