The Effect of Guard Line on Plasma Damage

The effective overetch time, the elapsed time after pattern seperation, determines the level of damage, because the plasma damage induced during metal etch process depends on the overetch time and only weakest pattem is damaged during process if patterns are connected. For the reduction of the effective overetch time, the narrow distribution of spacings between patterns are required, because the etch rate depends on the width of spacing and the lowest etch rate determines the total etch time and/or the effective overetch time. We have designed the dummy pattern i.e. guard line pattern for the narrow distribution of spacings. The level of damage depends on the connection configuration of outer pattern i.e. guard line pattern. The antenna patterns with floating guard line reveal less damage than the patterns with guard line connected to substrate and a simple floating guard line formation technology is proposed without increasing design complexity.