Self-bias calculation on a substrate in a process chamber with bias power for single or multiple frequencies

摘要

Methods for calculating a self-bias on a substrate in a process chamber may include measuring a DC potential of a substrate disposed on a substrate support of a process chamber while providing a bias power from a power source to a cathode at a first frequency; measuring a voltage, current and phase shift at a matching network coupled to the power source while providing the bias power; calculating an effective impedance of the cathode by determining a linear relationship between a calculated voltage and the measured DC potential of the substrate; calculating a first linear coefficient and a second linear coefficient of the linear relationship between the calculated voltage and the measured DC potential of the substrate; and calculating a self bias on the substrate by utilizing the first linear coefficient, second linear coefficient, measured DC potential of the substrate, effective impedance, and measured phase shift.

主权项

1. A method for calculating a self-bias on a substrate in a process chamber, comprising:
measuring a DC potential of a substrate disposed on a substrate support of a process chamber while providing a bias power from a power source to a cathode at a first frequency, wherein the DC potential is measured by a probe that contacts the substrate within the process chamber; measuring a voltage, a current and a phase shift while providing the bias power at the first frequency; calculating, by a central processing unit of a controller, an effective impedance of the cathode by determining a linear relationship between a calculated voltage and the measured DC potential of the substrate, wherein the calculated voltage is a function of the effective impedance, measured voltage, current and phase shift; calculating, by the central processing unit, a first linear coefficient and a second linear coefficient of the linear relationship between the calculated voltage and the measured DC potential of the substrate; and calculating, by the central processing unit, a self bias on the substrate by utilizing the first linear coefficient, second linear coefficient, measured DC potential of the substrate, effective impedance, and measured phase shift.