Stage Assembly Positioning with Dual Sensor Segmentation
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Solution Overview
Problem
Existing stage assembly systems for positioning devices in semiconductor processing face challenges in monitoring and controlling movement over large areas with high precision, due to limitations in sensor accuracy and resolution, particularly with two-dimensional optical image position sensors.
Innovation Solution
A stage assembly system that employs a dual sensor system, where a first sensor system with lower accuracy provides coarse movement control and initialization, while a second sensor system with higher accuracy, such as an encoder or interferometer, ensures precise positioning, and a two-dimensional image profile sensor reduces data points from N^2 to 2N, minimizing processing time and error accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single high-accuracy sensor system is used to monitor stage movement over large areas, then positioning precision is improved, but system complexity and cost increase significantly
Solution Approach 1:
The patent divides the sensor system into two segments: a first sensor system for coarse movement monitoring and a second sensor system for fine positioning. This segmentation allows each sensor to be optimized for its specific function, reducing overall system complexity while maintaining high positioning precision where needed.
Solution Approach 2:
The patent applies different sensor types to different spatial zones and functional requirements. The first sensor system covers large areas for coarse positioning, while the second sensor system provides high-precision measurement locally at critical positioning points, optimizing resource allocation and reducing unnecessary complexity.
2Area of stationary object
If a two-dimensional optical image position sensor is used to monitor large area movement, then coverage area is improved, but data processing time and computational overhead increase due to N^2 data points
Solution Approach 1:
The patent extracts only the essential data needed for positioning from the full two-dimensional image data. By using image profile sensors that capture one-dimensional intensity profiles along scan directions, the system extracts positioning information without processing all N^2 data points, significantly reducing computational overhead.
Solution Approach 2:
The patent transitions from processing two-dimensional image data (N^2 points) to processing one-dimensional intensity profiles (2N points) by integrating along scan directions. This dimensional reduction maintains positioning accuracy while dramatically reducing data processing requirements.
3Device complexity
If a single sensor system is used for both initialization and precise positioning, then device simplicity is improved, but measurement accuracy deteriorates during different operational phases
Solution Approach 1:
The patent implements a dynamic sensor selection strategy where the system automatically switches between the first sensor system during initialization and coarse movement, and the second sensor system during precise positioning. This dynamic adaptation ensures optimal measurement accuracy for each operational phase while maintaining manageable device complexity.
Solution Approach 2:
The patent changes the operational parameters of the sensor system by switching between different sensor types based on positioning requirements. The first sensor system operates during initialization with lower accuracy requirements, while the second sensor system activates during precise positioning with higher accuracy requirements, optimizing performance across different phases.
4Measurement precision
If high-resolution sensors are used throughout the entire travel range, then positioning resolution is improved, but tracking speed decreases due to increased data processing requirements
Solution Approach 1:
The patent applies high-resolution sensing only partially, specifically during precise positioning phases where the stage is near the target location. During initialization and coarse movement, the lower-resolution first sensor system suffices, reducing data processing requirements and maintaining high tracking speed while achieving the necessary positioning resolution when needed.
Data Source
AI summary
A stage assembly for positioning a device along a first axis, the stage assembly comprising: a base; a stage that retains the device and moves above the base; a mover assembly that moves the stage along the first axis relative to the base; a first sensor system that monitors the movement of the stage along the first axis, the first sensor system generating a first signal, the first sensor system having a first sensor accuracy; a second sensor system that monitors the movement of the stage along the first axis, the second sensor system having a second sensor accuracy that is different from the first sensor accuracy of the first sensor system, the second sensor generating a second signal; and a control system that controls the mover assembly using at least one of the first sensor and the second signal.