Resonant Frequency Substrate Thickness Measurement
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Solution Overview
Problem
Conventional semiconductor production systems face challenges in detecting issues with substrate processing chambers and layer deposition/etching processes in a timely manner, leading to potential production of faulty products and increased waste and costs.
Innovation Solution
The implementation of weight and/or layer thickness measurement systems that utilize resonant frequencies to determine the weight of a layer applied to a substrate or removed from it, integrated within cluster type substrate processing systems for in-situ or in-line monitoring during processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional substrate processing systems use stand-alone film thickness metrology like ellipsometry to measure layer thickness, then measurement can be performed, but the process is very slow and requires substrate removal from the system
Solution Approach 1:
The patent combines the measurement system with the substrate processing chamber by integrating a resonant frequency sensor directly into the chamber structure. This allows thickness measurements to be performed in-situ without removing substrates from the processing environment, merging the metrology function with the processing function to eliminate throughput bottlenecks.
Solution Approach 2:
The patent replaces conventional optical measurement systems (ellipsometry) with a mechanical resonance-based measurement system. By using resonant frequency shifts of a sensor structure to detect layer thickness changes, the system achieves precise measurements without requiring substrate removal or complex optical setups, thereby maintaining high productivity.
2Reliability
If layer deposition steps take place within complicated cluster type substrate processing systems under high temperature and very low pressure processing conditions, then material layers can be deposited onto substrates, but it can take significant time for a manufacturer to discover if one or more substrate processing steps and/or substrate processing chambers are not functioning properly
Solution Approach 1:
The patent implements real-time feedback measurement by continuously monitoring resonant frequency changes during the deposition process. This allows immediate detection of processing anomalies such as chamber contamination or equipment malfunctions, providing timely feedback to operators without waiting for post-processing inspections.
Solution Approach 2:
The measurement system performs preliminary detection of processing issues during the deposition process itself rather than after completion. By monitoring layer formation in real-time, the system can identify problems early in the process, allowing for corrective action before significant waste occurs.
3Measurement precision
If Quartz Crystal Microbalance (QCM) techniques are used to measure film thickness on coupons, then thickness measurements can be obtained, but this method only is effective during development of a recipe—not on a production and/or high-volume manufacturing (HVM) line
Solution Approach 1:
The patent creates a universal measurement system that functions in both development and production environments. The resonant frequency sensor integrated into the substrate processing chamber provides thickness measurement capabilities that are applicable across different manufacturing stages, from recipe development to high-volume manufacturing, eliminating the need for separate measurement approaches.
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
This solution enables early detection of processing issues, reduces waste and costs by allowing for immediate corrective action, and provides precise measurements of layer thickness without the need for substrate removal and external metrology.
Implementation Method 1
determine a resonant frequency for the support base and any object supported by the support base
Implementation Method 2
a strain sensor configured to measure strain induced in the support base by the oscillator source
Implementation Method 3
the oscillating frequency applied by the oscillator source to the support base is modified based on phase difference information determined by the phase locked loop module to locate a resonant frequency
Implementation Method 4
weight and/or layer thickness measurement systems that use resonant frequencies to determine the weight of an object (e.g., a layer applied to a substrate)
Implementation Method 5
determine a thickness of the layer based on the weight difference
Data Source
AI summary
Weight and/or layer thickness measurement systems include: (a) a support base for supporting an object; (b) an oscillator source applying oscillating frequency to the support base; (c) a strain sensor measuring strain induced in the support base by the oscillation; and (d) a phase locked loop module connected to the oscillator source and strain sensor. The oscillating frequency applied to the support base is modified based on phase difference information determined by the phase locked loop module to locate a resonant frequency for the support base and supported object. The resonant frequencies before and after processing are used to determine weight and/or thickness of a layer on the object. Cluster type substrate processing systems may include weight and/or layer thickness measurement systems, e.g., of these types, within a substrate handling chamber and/or in a separate chamber or station engaged with the substrate handling chamber.