DFM Challenges for 32nm Node with Double Dipole Lithography (DDL) and Double Patterning Technology (DPT)

Water-based 193nm immersion lithography enables the IC manufacturing to go beyond 45nm node. Presently, it is not clear if either high index lens or EUV will be in time for 32nm node. Double exposure and double patterning are both capable of further extending 193nm. Double exposure, such as double dipole lithography (DDL), forms the intended mask patterns on wafer in two consecutive mask exposures while the wafer stays on the chuck. For double patterning technology (DPT), after the first mask exposure, the wafer is sent to the develop and etch processes. Then it is to come back for a second mask exposure. The intended mask pattern is formed by two independent patterning steps. Successful mask decomposition is essential to enable DDL and DPT for 32nm node manufacturing. Due to the unique nature of patterning formation for each, we look into their respective DFM challenges.