Maskless pattern transfer using 355 nm laser

Low power near-ultraviolet laser can be employed in various pattern transfer techniques such as maskless lithography and organic film ablation. Laser maskless lithography allows rapid prototyping using thin as well as thick photoresist films. Non-photosensitive organic films can be patterned by laser ablation, and this technique is applied in creating micro-molds for metal deposition using electroplating and electroless deposition. This paper presents experimental results, a quantitative study and modeling of laser maskless processing using desktop Nd:YAG laser system using four different photoresists. Process variables were experimentally optimized to identify the appropriate laser parameters that would yield reliable and reproducible patterns. A finite element thermal model of the ablation process was created to investigate the effects of different substrate materials on the process quality.

► This paper presents quantitative study and experimental results for laser maskless processing using desktop Nd:YAG laser and four different photoresists.
► It also provides optimal parameters for NUV laser lithography using positive and negative photoresists.
► The study investigates the application of NUV laser in patterning polyimide thin films.
► Thermal modeling using finite element analysis is used to analyze and investigate the polyimide ablation mechanisms.
► The effect of different substrates on the polyimide ablation is also investigated and analyzed using experimental setup and finite element modeling.