Linda K. Somerville

A semiconductor memory development and manufacturing perspective

Semiconductor memories are growing in importance as they are now fundamental in every electronic system and offer new manufacturing and development challenges and opportunities. From a manufacturing point of view, the industry has undergone consolidation and today very few players are able to supply the high wafer volumes required by the global market. From a technology development point of view, new applications requiring lower power, higher memory density and improved performance creates opportunities for alternative memory technologies. Moreover, the shift to 3-dimensional integration and to new system architectures result in both manufacturing and technology challenges.

Process effects in flare measurement

Flare has become a significant problem for low K1 lithography. Several authors have reported measurement of flare in projection lenses. Most of the work is based on the Flagello-Kirk method using resist clearing dose. To measure the flare reliably and accurately using this method the contribution of the process needs to be understood. In this paper we present data looking at the influence of such effects on the measured flare.

Understanding focus in projection lithography systems

Characterizing best focus for lithographic patterns is a very common task. It has been observed that the estimated best focus changes considerably with substrate type and substrates change quite frequently in process development. Such effects are seen even when the resist thickness is not altered. In this paper we will present data to identify the cause of the change and throw some light on the interaction between substrate and scanner leveling system.