Method and Apparatus for Controlling Substrate DC-Bias and Ion Energy and Angular Distribution During Substrate Etching

摘要

In addition to the impedance matching circuit provided in the radio frequency (RF) power transmission path to the bias electrode, a variable capacitor is provided in the RF transmission path to the bias electrode. The RF power supply operates in a pulsed mode to transmit pulses of RF power through the RF power transmission path to the bias electrode. The capacitance of the variable capacitor is set to control the rate of build-up of the DC bias voltage on the substrate present above the bias electrode during each pulse of RF power. The DC bias voltage build-up rate on the substrate controls the ion energy distribution and ion angular distribution in the plasma exposed to the electromagnetic field emanating from the substrate.