COMPARATIVE STUDY OF CU SEEDING LAYER BY CVD AND ELECTROLESS DEPOSITION METHODS FOR VLSI CU INTERCONNECT METALLIZATION

摘要

CVD Cu seed technology has been actively pursued to replace the conventional PVD Cu seed that is essential for the subsequent Cu filling of via/trench by the electroplating technology in sub-0.18μm VLSI technology. In this work, electroless Cu deposition is employed an alternative contending technology to CVD Cu for seeding layer formation. A comparative study between CVD and electroless technique revealed comparable results for the two techniques. Highly (111) textured electroless Cu seed layer is also obtained in this work. The electroless copper deposition method has great potential for use as a Cu seed in ULSI copper metallization due to its to its very low tool cost and excellent step coverage. Being a wet process, EL-Cu technology offers the advantage of easy integration with existing Cu plating process. Moreover, EL Cu is deposited at a much lower temperature of around 70°C as compared to the typical CVD process temperature.