Novellus Systems Incorporated

Viral Hazari

Stephen E Hilliker

Zia Karim

Sriram Seshagiri

A plasma-enhanced chemical vapor deposition system includes a balancing inductor in the circuit path between the radio frequency generator and the &ldquo;showerhead&rdquo; that is used to introduce reactant gases to the system. The balancing inductor reduces the resonant frequency of the circuit to a level below the frequency of the signal produced by the radio frequency generator. Since the effective capacitance of the showerhead electrode varies monotonically with the power input to the plasma, fluctuations in the power delivered to the plasma will be self-correcting the system will be stabilized. For example, a drop in the power to the plasma will reduce the resonant frequency, but the corresponding reduction in the effective capacitance of the showerhead electrode will tend to increase the resonant frequency, thereby offsetting the change and stabilizing the system. Systems according to this invention are particularly useful in solving the plasma stability problems of using NF,or a mixture of NF,and one or more inert gases for the in situ cleaning of PECVD chambers used for depositing dielectric films.

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San Jose, CA, United States of America

Viral Hazari