Integrated Wafer Bow Measurement for Real-Time Deposition Control
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Solution Overview
Problem
Current wafer bow measurement technologies are limited by being unsuitable for in-situ, real-time measurements, often requiring stand-alone metrology tools that provide localized and non-accurate data, which can lead to wafer damage and processing variations due to inadequate gap detection between the upper electrode and the wafer in processing chambers.
Innovation Solution
Integration of an optical sensor, such as a laser triangulation-based distance sensor, on a wafer processing tool with linear and rotational stages for real-time wafer bow measurements, combined with a calibration standard and sensors for environmental compensation, enabling accurate and continuous monitoring and control during deposition processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If stand-alone metrology tools are used for wafer bow measurement, then measurement capability is provided, but measurement precision and real-time monitoring are insufficient
Solution Approach 1:
The patent combines the metrology tool with the deposition tool into an integrated system. The optical sensor is mounted on the deposition tool's electrostatic chuck assembly, allowing simultaneous deposition and wafer bow measurement. This eliminates the need for separate stand-alone metrology tools and enables real-time measurements during the deposition process, resolving the contradiction between measurement capability and time delay.
Solution Approach 2:
The integrated optical sensor performs wafer bow measurements in real-time during the deposition process, providing preliminary measurement data before the deposition is complete. This allows for continuous monitoring and potential process adjustments, eliminating the time delay associated with post-deposition stand-alone measurements.
2Productivity
If optical sensor is integrated on deposition tool, then real-time measurement capability is achieved, but device complexity increases
Solution Approach 1:
The optical sensor system is designed to perform multiple functions: measuring wafer bow during deposition, providing real-time feedback for process control, and enabling continuous monitoring without requiring separate measurement equipment. This multi-functionality justifies the added complexity by delivering significant productivity improvements through real-time data.
Solution Approach 2:
The patent introduces an intermediary processing system that receives raw optical sensor data, processes it to extract wafer bow measurements, and provides feedback to the deposition control system. This intermediary layer manages the complexity by automating data processing and integration, making the system manageable while maintaining real-time capabilities.
3Reliability
If in-situ measurements are performed during deposition, then process control is improved, but measurement accuracy may be affected by environmental factors
Solution Approach 1:
The integrated system implements real-time feedback by continuously monitoring wafer bow measurements during deposition and providing data to the process control system. This feedback loop allows for immediate detection of wafer bow changes and enables process adjustments to maintain specification compliance, improving reliability through continuous verification.
Solution Approach 2:
The system monitors changes in measurement parameters (wafer bow values) over time during the deposition process. By tracking parameter evolution rather than relying on single-point measurements, the system can distinguish between actual wafer bow changes and measurement noise, improving accuracy while maintaining real-time monitoring capabilities.
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
Enables real-time, accurate wafer bow measurements that improve process monitoring and control, reducing the risk of wafer damage and processing variations, and facilitating effective bow compensation in high-volume manufacturing.
Implementation Method 1
an optical sensor, such as a laser triangulation-based distance sensor
Data Source
AI summary
In some examples, a wafer bow measurement system comprises a measurement unit including: a wafer support assembly to impart rotational movement to a measured wafer supported in the measurement unit; an optical sensor; a calibration standard to calibrate the optical sensor; a linear stage actuator to impart linear direction of movement to the optical sensor; a wafer centering sensor to determine a centering of the measured wafer supported in the measurement unit; and a wafer alignment sensor to determine an alignment of the measured wafer supported in the measurement unit.