In-Situ Sheet Resistance Measurement Using Eddy Sensors
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Solution Overview
Problem
The existing methods for in-situ monitoring of seed layer oxidation in substrates post-metallization are inadequate, as offline sheet resistance measurements are prone to variable wait times, leading to inaccurate characterization of Vacuum Pretreatment Module (VPM) performance due to potential re-oxidation of substrates before measurement.
Innovation Solution
A Vacuum Pre-treatment Module (VPM) metrology system utilizing an eddy sensor with a sender and receiver sensor pair, configured to measure sheet resistance in-situ during production, activated by a trigger sensor upon substrate proximity, allowing for real-time inline measurements to assess the performance of the VPM and prevent oxidation-related defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If offline sheet resistance measurements are used, then measurement simplicity is maintained, but measurement precision deteriorates due to variable wait times and substrate re-oxidation
Solution Approach 1:
The system performs sheet resistance measurements immediately after VPM treatment while the substrate is still in the vacuum chamber, before the substrate can re-oxidize upon exposure to air. This preliminary action captures the true treatment effect without the confounding variable of post-treatment oxidation.
Solution Approach 2:
The patent introduces an in-situ measurement system that operates within the vacuum chamber environment, acting as an intermediary between the VPM treatment and the substrate. This allows measurements to be taken in the controlled vacuum environment without requiring substrate removal and subsequent re-oxidation.
2Measurement precision
If in-situ measurement systems are implemented, then measurement precision improves by eliminating re-oxidation effects, but device complexity increases
Solution Approach 1:
The measurement system is designed to be integrated within the existing VPM vacuum chamber infrastructure, utilizing the same vacuum environment and substrate handling mechanisms. This multi-functional approach allows the measurement system to operate without requiring separate dedicated equipment, thereby reducing overall complexity.
Solution Approach 2:
The patent replaces complex mechanical measurement systems with electrical resistance measurements that can be performed through non-contact or minimal-contact methods within the vacuum chamber. This substitution simplifies the measurement mechanism while maintaining high precision.
3Ease of operation
If substrate wait time before measurement is extended, then measurement accessibility is improved, but measurement precision deteriorates due to seed layer oxidation
Solution Approach 1:
The system performs measurements automatically immediately after VPM treatment without requiring substrate removal or manual handling. The substrate remains in the vacuum chamber where it can be measured in-situ, eliminating the need for waiting periods and manual intervention while maintaining measurement accessibility.
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 accurate, real-time measurement of sheet resistance across a wide range (0.001 to 50,000 ohms-per-square) with reduced noise and signal stability, effectively qualifying VPM performance and preventing substrate defects by minimizing queue time and re-oxidation, thereby enhancing production yield.
Implementation Method 1
an eddy sensor, the eddy sensor including a sender sensor and a receiver sensor defining a gap between them for accepting an edge of a substrate to be tested
Data Source
AI summary
In some examples, a Vacuum Pre-treatment Module (VPM) metrology system is provided for measuring a sheet resistance of a layer on a substrate. The system may comprise an eddy sensor including a sender sensor and a receiver sensor defining a gap between them for accepting an edge of a substrate to be tested. A sensor controller receives measurement signals from the eddy sensor. A data processor processes the measurement signals and generates sheet resistance values for the layer on the substrate.