Wafer Alignment via Dynamic Compensation Parameters
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Solution Overview
Problem
Existing semiconductor manufacturing processes face inaccuracies in wafer placement due to sensor position deviations, robot arm misalignment, and operator errors, leading to defects and long calibration times, especially when using dual robot arms.
Innovation Solution
A method called Dynamic Alignment III, which involves preliminary station calibration to teach robot positions, create compensation parameters for sensor and robot arm offsets, and fine-tune placements using metrology-based alignment to optimize wafer placement repeatability across semiconductor manufacturing equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensors are used to increase wafer placement accuracy, then measurement precision is improved, but device complexity increases due to multiple sensors and calibration requirements
Solution Approach 1:
The system performs self-calibration by automatically determining robot arm offsets through coordinated movement between the transfer module and processing module without requiring manual operator calibration. The calibration process is automated, with the system teaching itself the correct positions and offsets through controlled wafer movements and sensor measurements.
Solution Approach 2:
The system uses sensors to measure wafer positions and provides feedback to calculate compensation values for robot arm offsets. This feedback loop enables continuous refinement of placement accuracy by comparing actual sensor readings with expected positions and adjusting accordingly.
2Productivity
If multiple robot arms are used to increase transfer speed and flexibility, then productivity is improved, but manufacturing precision deteriorates due to operational differences between arms
Solution Approach 1:
The system determines separate compensation values for each robot arm based on their individual operational characteristics. By calculating arm-specific offset values through calibration procedures, the system accounts for differences between arms while maintaining consistent wafer placement accuracy across all transfers.
3Measurement precision
If manual calibration is performed to account for sensor and robot arm errors, then measurement precision is improved, but loss of time increases due to long calibration durations
Solution Approach 1:
The system performs calibration procedures in advance during system setup or maintenance periods, storing the determined compensation values for use during normal production operations. This preliminary calibration action separates the time-consuming measurement process from production time, allowing accurate placement without time loss during manufacturing.
Data Source
AI summary
Methods and systems to optimize wafer placement repeatability in semiconductor manufacturing equipment using a controlled series of wafer movements are provided. In one embodiment, a preliminary station calibration is performed to teach a robot position for each station interfaced to facets of a vacuum transfer module used in semiconductor manufacturing. The method also calibrates the system to obtain compensation parameters that take into account the station where the wafer is to be placed, position of sensors in each facet, and offsets derived from performing extend and retract operations of a robot arm. In another embodiment where the robot includes two arms, the method calibrates the system to compensate for differences derived from using one arm or the other. During manufacturing, the wafers are placed in the different stations using the compensation parameters.