Polymer Based Dual Damascene Process for Fine Pitch RDL Advanced Packaging

In this paper, a trench-first dual damascene process is used to demonstrate 1 μm L/S meander trenches and 1 μm CD and space vias. A non-phototype polymer material is selected as the dielectric layer and two layers of 1 μm dielectric are spin-coated. The issues and costs associated with the chemical mechanical planarization (CMP) process are eliminated. In the lithography process, a 1.5 μm thick photoresist was spin-coated using optimized exposure energy patterns of 1 μm L/S trench and 1 μm CD and space vias, respectively. Finally, dry etch parameters were fine-tuned to complete etching of 1 μm L/S meander trenches and 1 μm CD and space vias.