| Abstract |
Plasma etching is an important process in the semiconductor manufacturing process. In order to preciselycontrol the ion energy for better process quality, a tailored pulse-shape voltage waveform is applied tothe plasma reactor table. Traditionally, a linear amplifier is used to generate this waveform, which resultsin poor efficiency. This paper proposes a switched-mode power amplifier as a substitute to the traditionallinear amplifier. The electric equivalent circuit of the plasma reactor is introduced and a basic topologyfor the switched-mode power amplifier is derived. The basic topology is able to generate the requiredwaveform but it has a low efficiency of charging the capacitive load in practice. Therefore, an efficiencyimprovedtopology is proposed by adopting resonant charging. A prototype is built in order to validatethe research. The experiments show that the presented solution yields a significantly reduced input powercompared to the normally used linear amplifier in this application. |
