Edge Ring Height Compensation for Plasma Etch Wear
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Solution Overview
Problem
Substrate processing systems face challenges in compensating for the wear of tunable edge rings, which affects plasma confinement and etch uniformity, as existing systems lack effective mechanisms for directly measuring edge ring erosion.
Innovation Solution
A controller system is introduced that includes an edge ring wear calculation module to estimate erosion rates based on user inputs, usage periods, and process parameters, and an actuator control module to adjust the edge ring height accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct measurement tools for edge ring erosion are used, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent introduces an intermediary calculation module that computes erosion rates based on process parameters (power, pressure, temperature, composition) rather than direct measurement. This mediator translates easily measurable process variables into erosion estimates, avoiding the need for complex direct measurement tools while maintaining useful precision for compensation purposes
2Reliability
If edge ring height is adjusted frequently to compensate for wear, then plasma confinement is maintained, but productivity decreases
Solution Approach 1:
The system performs preliminary calculation of erosion rates based on process parameters before actual wear occurs. By predicting the amount of wear in advance, the system can plan and execute height adjustments at optimal intervals rather than reacting to performance degradation, thus maintaining plasma confinement while minimizing interruptions to productivity
Solution Approach 2:
The patent implements a feedback loop where erosion rates are continuously calculated from process parameters, and height adjustments are made based on cumulative erosion. This closed-loop control maintains plasma confinement reliability while optimizing the timing and magnitude of adjustments to minimize impact on productivity
Data Source
AI summary
A method for adjusting a height of an edge ring arranged around an outer portion of a substrate support includes receiving at least one input indicative of one or more erosion rates of the edge ring. The at least one input includes a plurality of erosion rates for respective usage periods of a substrate processing system. The method further includes determining at least one erosion rate of the edge ring using the plurality of erosion rates for the respective usage periods, monitoring an overall usage of the edge ring and storing the overall usage of the edge ring in a memory, calculating an amount of erosion of the edge ring based on the determined at least one erosion rate and the overall usage of the edge ring, and adjusting the height of the edge ring based on the calculated amount of erosion to compensate for the calculated amount of erosion.