Sensor-to-Sensor Matching for Plasma Chamber Consistency
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Solution Overview
Problem
Achieving consistent and predictable performance across multiple plasma processing chambers is challenging due to measurement errors from sensor variability, leading to discrepancies in device performance and reduced yield.
Innovation Solution
The method involves using a golden reference sensor to adjust plasma sensor values across chambers by determining baseline and signature plasma conditions, applying linear or non-linear equations to compensate for differences, ensuring consistent plasma processing across multiple chambers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If direct metrology measurements on patterned test wafers are used for chamber matching, then structural dimensions can be matched, but plasma related parameters and non-measured structural dimensions cannot be matched
Solution Approach 1:
The patent introduces plasma sensors as an intermediary measurement tool that directly measures plasma parameters (ion flux, electron temperature, radical density) without requiring patterned test wafers. This mediator enables comprehensive chamber matching including both structural dimensions and plasma parameters, resolving the limitation of direct metrology measurements.
Solution Approach 2:
The patent replaces the mechanical/direct measurement system (physical contact with patterned wafers) with a field-based measurement system (plasma sensors measuring electromagnetic and particle properties). This substitution enables measurement of plasma parameters that cannot be accessed through direct physical measurement of structured wafers.
2Reliability
If sensor values are used for chamber matching, then plasma parameters can be monitored, but measurement errors from sensor variability reduce accuracy
Solution Approach 1:
The patent transforms sensor readings from absolute values to relative ratios by comparing measurements across multiple sensors. This parameter transformation (from absolute to relative measurement) eliminates the effect of sensor variability and calibration differences, improving measurement precision while maintaining reliable plasma parameter monitoring.
Solution Approach 2:
The patent implements a feedback mechanism where sensor measurements are continuously compared and used to adjust chamber operating parameters. This closed-loop feedback compensates for sensor variability by using the relative information from multiple sensors to maintain accurate plasma parameter control despite individual sensor drift or calibration differences.
3Extent of automation
If multiple sensors are deployed across chambers, then comprehensive plasma monitoring is achieved, but sensor variability and impedance mismatches cause measurement discrepancies
Solution Approach 1:
The patent applies homogeneity by using identical sensor types and configurations across all chambers, ensuring that measurement principles and response characteristics are uniform. This standardized approach, combined with ratio-based measurements, minimizes the impact of sensor variability and impedance mismatches while maintaining comprehensive automated plasma monitoring.
Data Source
AI summary
Embodiments are described herein for sensor-to-sensor matching methods for chamber matching across multiple plasma processing chambers. For disclosed embodiments, a baseline signature in a first processing chamber is compared to a signature generated in a second processing chamber in order to adjust and match sensor display values for the second processing chamber. The baseline signature is determined using a golden reference sensor disposed within the first processing chamber and plasma sensors monitoring a baseline plasma. The signature of the plasma is determined using the golden reference sensor disposed within the second processing chamber and plasma sensors monitoring the plasma. Differences are determined between the baseline signature and the signature, and a display value for the plasma sensors for the second processing chamber is adjusted based on the differences to provide chamber matching with the first processing chamber. The golden reference sensor can be a wafer with embedded sensors.