Wafer Storage Elevator Laser Detection for Shifted Wafer Alignment
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Solution Overview
Problem
Semiconductor wafers in storage elevators can become misaligned, leading to potential damage during handling by robotic arms due to improper alignment, which existing systems fail to detect effectively.
Innovation Solution
A wafer position shift detection system using a storage elevator with sidewalls, mirror blocks, and a laser beam setup to detect misalignment by blocking the laser beam transmission when wafers are out of position, communicating with a controller to alert and correct alignment issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wafers are stored in storage elevators without alignment detection, then the system structure remains simple, but wafer misalignment occurs leading to potential damage during robotic handling
Solution Approach 1:
The patent replaces complex mechanical alignment detection mechanisms with an optical detection system using laser beams and sensors. The laser beam passes through the storage elevator slots, and when a wafer is misaligned, it blocks the beam, triggering an alignment alert. This optical substitution simplifies the overall system while improving reliability.
Solution Approach 2:
The patent introduces laser beams as an intermediary element to detect wafer alignment. The laser beam serves as a mediator between the wafer position and the detection system, allowing non-contact alignment monitoring without requiring direct mechanical interaction with the wafers.
2Measurement precision
If existing alignment detection methods are used, then the system is simpler, but misalignment detection precision is insufficient leading to undetected wafer shifts
Solution Approach 1:
The patent replaces imprecise mechanical detection methods with optical laser-based detection. The laser beam provides a precise reference line, and any deviation caused by wafer misalignment is easily detectable, significantly improving measurement precision while keeping the system relatively simple.
Solution Approach 2:
The patent transitions from mechanical contact-based detection to optical field-based detection, adding a new dimensional approach to alignment measurement. The laser beam creates an optical reference plane that enables precise detection of wafer position deviations without physical contact.
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
Ensures accurate detection and correction of wafer misalignment, preventing damage and ensuring proper handling by robotic arms, enhancing the reliability of semiconductor processing.
Implementation Method 1
transmit a laser beam to a first mirror to reflect the laser beam to a second mirror to reflect the laser beam to at least one receive sensor
Data Source
AI summary
A wafer storage elevator and method for detecting wafer position shift. The elevator includes a first storage elevator sidewall, a second storage elevator sidewall, and a storage seat positioned between the first and second storage elevator sidewalls. A first mirror block is coupled to a front side of the storage seat having a mirror positioned on a top surface of the block, and a second mirror block is coupled to the front side of the storage seat having a mirror that is positioned on the top surface of the second mirror block. The mirror of the first mirror block reflects a laser beam from an emission sensor to the second mirror block, and the mirror of the second mirror block reflects the laser beam from the mirror of the first mirror block to a receive sensor. A wafer misalignment is determined based upon an output of the receive sensor.