Dependence of plasma process induced damage on the transistor gate area

Until now, antenna ratio was considered one of the most important parameters for plasma induced damage, and tolerable antenna ratio is very important for circuit designers to guarantee high yield circuits. In this paper, the dependence of plasma induced damage on the gate area is characterized using novel test patterns. The test chip is fabricated using 0.15 μm CMOS technology with low-k IMD material. The variation of gate current is used to detect the plasma induced damage. It is shown that the failure rates of transistor increase as the gate area in the transistor increases although the antenna ratio maintains constant. Therefore, to guarantee the reliability of the gate oxide and transistors, we propose that the dependence of plasma induced damage on gate area should be considered when defining the maximum tolerable antenna ratio