Capacitive Plasma Chamber Sensing for Redeposition Monitoring
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Solution Overview
Problem
Existing plasma processing chambers face challenges in monitoring chamber conditions, leading to processing non-uniformity and instability due to redeposition layers on interior surfaces, which result in process drift, decreased throughput, and yield loss, as current methods lack direct measurement of redeposition thickness and require frequent chamber openings for cleaning.
Innovation Solution
Implementing capacitive sensors at strategic locations within the plasma processing chamber, such as the chamber wall, lid, evacuation port, and ring structure, to measure capacitance changes related to deposition and erosion, enabling real-time monitoring and optimization of in-situ cleaning procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If in-situ chamber cleaning is performed periodically, then process drift is reduced, but chamber downtime increases due to frequent openings
Solution Approach 1:
The capacitive sensor continuously monitors redeposition layer thickness in advance, enabling predictive triggering of ICC before process drift occurs, rather than relying on predetermined intervals or waiting for excursions to be detected
Solution Approach 2:
The sensor provides real-time feedback on chamber wall condition, allowing the ICC process to be triggered based on actual redeposition thickness measurements, creating a closed-loop control system that optimizes cleaning frequency
2Object-generated harmful factors
If chamber opening is used for cleaning, then redeposition layers are removed, but throughput decreases due to pumping and revalidation time
Solution Approach 1:
The capacitive sensor replaces physical chamber opening and manual cleaning with non-intrusive electrical field-based measurement, allowing continuous monitoring without mechanical intervention or chamber evacuation
Solution Approach 2:
The sensor enables the chamber to self-monitor its own condition, providing autonomous detection of redeposition layers without requiring external inspection or intervention
3Ease of operation
If predetermined cleaning intervals are used, then chamber maintenance is simplified, but cleaning frequency is suboptimal leading to process drift
Solution Approach 1:
The system transitions from static predetermined cleaning intervals to dynamic, condition-based triggering, where ICC is initiated based on real-time sensor measurements of actual chamber wall condition
Solution Approach 2:
The cleaning trigger changes from a time-based parameter to a condition-based parameter (redeposition thickness), allowing the system to adapt cleaning frequency to actual chamber state rather than following a fixed schedule
4Device complexity
If no direct measurement of redeposition thickness is available, then chamber design remains simple, but process monitoring precision is insufficient
Solution Approach 1:
The capacitive sensor acts as an intermediary measurement tool that indirectly measures redeposition thickness by detecting changes in electrical field capacitance caused by dielectric layer formation on chamber walls
Solution Approach 2:
Physical contact-based measurement methods are replaced with non-contact capacitive sensing, eliminating the need for direct physical access to chamber walls while enabling precise thickness measurement
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The capacitive sensors allow for direct measurement of redeposition layers, predicting process stability and drift, reducing preventative maintenance frequency, and improving productivity and yield by optimizing ICC routines and identifying excursions in real-time.
Implementation Method 1
capacitive sensors and capacitive sensing locations for plasma chamber condition monitoring
Data Source
AI summary
Capacitive sensors and capacitive sensing locations for plasma chamber condition monitoring are described. In an example, a plasma processing chamber includes a chamber wall surrounding a processing region. A chamber lid is over the chamber wall and above the processing region. A chamber floor is beneath the chamber wall and below the processing region. A support pedestal is in the processing region and below the chamber lid and above the chamber floor, and the support pedestal surrounded by the chamber wall. A capacitive sensor module can be in an opening of the chamber wall. The chamber lid can include a capacitive sensor module. The chamber floor can include an evacuation port and a capacitive sensor module within or adjacent to the evacuation port. The support pedestal can include a ring structure surrounding a substrate support region, and a capacitive sensor module in an opening of the ring structure.