Etch Rate Modeling for Plasma Chamber Matching
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Solution Overview
Problem
Plasma etch rate variability within and between chambers leads to inconsistent wafer processing, particularly when using different RF generators, resulting in challenges in maintaining uniform etch rates across multiple plasma systems.
Innovation Solution
An etch rate modeling approach that uses multiple parameters such as voltage, current, power, and frequency to facilitate in-chamber and chamber-to-chamber matching, allowing for processor-executed adjustments to achieve consistent etch rates without the need for an etch rate measurement device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple plasma chambers are used for wafer etching, then processing capacity is improved, but etch rate variability chamber-to-chamber increases
Solution Approach 1:
The patent applies parameter changes by adjusting RF power, gas flow rates, and pressure settings for each plasma chamber based on measured etch rates. The system dynamically modifies process parameters to compensate for chamber-specific variations, achieving uniform etch rates across multiple chambers without requiring identical hardware configurations.
Solution Approach 2:
The patent implements feedback control by continuously monitoring etch rates using measurement devices in each plasma chamber. The measured etch rates are fed back to the control system, which automatically adjusts process parameters for each chamber to maintain target etch rates, thereby eliminating chamber-to-chamber variability.
2Productivity
If RF power is increased to improve etch rate, then productivity is improved, but etch rate variability over time increases
Solution Approach 1:
The patent applies periodic action by implementing continuous real-time monitoring and adjustment of RF power during the etching process. Rather than maintaining a fixed high power setting, the system periodically measures etch rates and adjusts power levels to maintain consistency, enabling high productivity without sacrificing etch rate stability over time.
Solution Approach 2:
The patent implements dynamics by transitioning from static RF power settings to dynamic, real-time adjustment of power levels. The system continuously adapts RF power based on measured etch rates, allowing the process to maintain optimal productivity while compensating for temporal variations in etch rate through active control.
3Adaptability or versatility
If different RF generators are used in plasma chambers, then system flexibility is improved, but etch rate matching between chambers becomes more difficult
Solution Approach 1:
The patent applies universality by implementing a common measurement and control system that works across multiple plasma chambers with different RF generators. The etch rate measurement device and control algorithm are designed to be generator-agnostic, allowing the system to handle various RF generator types while maintaining consistent etch rate matching through a unified feedback control approach.
Data Source
AI summary
A method includes receiving a voltage and current measured at an output of an RF generator of a first plasma system and calculating a first model etch rate based on the voltage and current, and a power. The method further includes receiving a voltage and current measured at an output of the RF generator of a second plasma system, determining a second model etch rate based on the voltage and current at the output of the RF generator of the second plasma system, and comparing the second model etch rate with the first model etch rate. The method includes adjusting a power at the output of the RF generator of the second plasma system to achieve the first model etch rate associated with the first plasma system upon determining that the second model etch rate does not match the first model etch rate. The method is executed by a processor.