PEALD Wafer Dechuck Detection Using RF Phase Shift
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Solution Overview
Problem
Existing substrate processing systems, particularly those using Plasma Enhanced Atomic Layer Deposition (PEALD), lack the capability to detect whether a wafer is dechucked during processing, which can lead to poor film uniformity and reduced yield.
Innovation Solution
A substrate processing system equipped with a reaction chamber, a radio frequency (RF) generator, a matching unit, and a phase shift detector or network analyzing unit, which allows for the detection of phase shifts or transmission coefficients to determine if a wafer is dechucked, using specific thresholds and time lengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If PEALD process is used for substrate processing, then deposition quality is improved, but the capability to detect dechucked wafers is lost
Solution Approach 1:
The patent introduces an intermediary detection system that uses RF signal transmission through the wafer-chuck interface to indirectly detect wafer attachment status. Instead of directly observing mechanical attachment, the system measures electrical signal characteristics (phase shift, impedance changes) that change when the wafer dechucks, thereby enabling detection in PEALD processes without LRF modules.
2Difficulty of detecting and measuring
If LRF module is used for dechuck detection, then detection capability is improved, but device complexity increases
Solution Approach 1:
The patent makes the existing RF generator and matching unit serve a dual function: both performing their primary deposition function and enabling dechuck detection. The RF signals already present in the PEALD process are utilized for detection purposes, eliminating the need for separate detection hardware and reducing overall system complexity.
3Productivity
If dechuck detection is implemented, then yield is improved, but process interruption risk increases
Solution Approach 1:
The patent implements a feedback mechanism where the detection system continuously monitors RF signal characteristics and provides real-time information about wafer attachment status. This feedback enables operators to take corrective action before dechucking causes significant quality defects, thereby improving yield while maintaining process continuity through timely interventions rather than frequent interruptions.
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 system effectively detects dechucked wafers by measuring phase shifts or transmission coefficients, enabling timely intervention to maintain process integrity and improve yield.
Implementation Method 1
a phase shift detector connected to the reaction chamber in parallel and configured to detect a phase shift between a signal going into the upper electrode and a signal coming out of the lower electrode
Implementation Method 2
a network analyzing unit connected to the reaction chamber in parallel and configured to detect a transmission coefficient of the reaction chamber
Implementation Method 3
a matching unit disposed between the reaction chamber and the RF generator and configured to adjust the impedance of the reaction chamber for the generated high frequency power to be more effective in the processing
Data Source
AI summary
A substrate processing system with capabilities to detect whether a wafer is dechucked during process is disclosed. An embodiment of the present disclosure's system comprises a reaction chamber provided with an upper electrode and a lower electrode, and configured to process a wafer, a radio frequency generator configured to generate a high frequency power to process the wafer in the reaction chamber, a matching unit disposed between the reaction chamber and the generator and configured to match the generated high frequency power from the generator for use in the reaction chamber, a phase shift detector connected to the reaction chamber in parallel and configured to detect a phase shift between a signal going into the upper electrode and a signal coming out of the lower electrode, and a controller connected to the phase shift detector and configured to receive parameters, to determine and to display the status of the wafer.