Systems and methods for directing power to an edge ring from a nonsinusoidal bias supply

By employing a phase-delayed control system with main and TES NSB power supplies, the uniformity of plasma processing is improved, addressing edge defects and enhancing wafer yield in plasma processing systems.

WO2026142881A1PCT designated stage Publication Date: 2026-07-02LAM RES CORP
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Patent Information

Authority / Receiving Office
WO · WO
Patent Type
Applications
Current Assignee / Owner
LAM RES CORP
Filing Date
2025-12-15
Publication Date
2026-07-02

AI Technical Summary

Technical Problem

In plasma processing systems, the semiconductor wafer is not processed uniformly due to asymmetrical power distribution caused by chamber capacitances, leading to edge defects such as tilt and ellipticity, which are exacerbated by the coupling between the edge ring and the electrostatic chuck.

Method used

Implementing a system with a main and tunable edge sheath (TES) nonsinusoidal bias (NSB) power supply, controlled by a phase delay to align wafer and edge ring voltages, using capacitive dividers and shunt capacitors to mitigate chamber capacitance effects, and actively controlling power distribution through phase shifts.

Benefits of technology

This approach enhances the control over edge ring voltage, reduces edge defects, and improves wafer yield by ensuring uniform plasma processing across the wafer.

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Abstract

Systems and methods for directing power to an edge ring from a nonsinusoidal bias (NSB) supply are described. One of the systems includes a first capacitor circuit coupled between an output of a main NSB power supply and an electrostatic chuck (ESC) of a plasma chamber. The system includes a second capacitor circuit coupled between an output of a tunable edge sheath (TES) NSB power supply and an edge ring. The edge ring surrounds the ESC. Moreover, a phase or time delay controller is described for an active and efficient control of power distribution between the main NSB power supply that powers the ESC and the TES NSB power supply that powers the edge ring.
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