Wafer Receptacle Interferometer for Transfer Robot Positioning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing transfer robot systems face challenges in accurately determining the taught position within a wafer receptacle, especially when there are assembly failures between the wafer receptacle and the stage, leading to inaccurate wafer transfer.
Innovation Solution
A transfer robot system equipped with an interferometer and a wafer receptacle featuring multiple optical elements and reflectors, which calculate optical interference peaks to determine the taught position based on variations in the interference spectrum, ensuring accurate positioning and horizontal posture evaluation of the wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical sensors are used to determine taught position, then the system can detect position, but the measurement precision is insufficient when assembly failures occur between wafer receptacle and stage
Solution Approach 1:
The patent replaces mechanical/optical blockage-based detection with optical interference-based detection. Instead of using optical sensors that detect blockage of light paths (mechanical system limitation), the invention uses interferometers to detect optical interference patterns caused by wafer thickness variations, enabling precise measurement independent of mechanical assembly accuracy between receptacle and stage.
Solution Approach 2:
The patent changes the detection parameter from binary blockage detection (sensor blocked/not blocked) to continuous optical interference pattern analysis. By measuring interference spectrum variations that correspond to different wafer thicknesses and positions, the system achieves continuous, high-precision position determination rather than discrete blockage states.
2Measurement precision
If multiple optical elements and reflectors are added to improve position accuracy, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent makes the wafer receptacle multi-functional by integrating it with optical measurement components. The receptacle body serves both as a container for wafers and as a mounting structure for reflectors and optical elements, while also serving as part of the optical measurement path. This eliminates the need for separate measurement devices and reduces overall system complexity.
Solution Approach 2:
The patent merges the wafer receptacle structure with the optical measurement system. Reflectors are disposed on internal surfaces of the receptacle body, and optical elements are integrated into the receptacle structure itself, combining two previously separate functions (wafer handling and position measurement) into a single integrated unit.
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
The system improves the accuracy of the taught position determination and ensures the wafer is placed horizontally, enabling precise wafer transfer by using optical interference peaks to identify contact points and shifts during the transfer process.
Implementation Method 1
The interferometer converts a reflected light spectrum into an interference spectrum. Here, the reflected light spectrum is based on the reflected light received by the first optical element, and the interference spectrum is generated between the wafer supported by the support ribs and the first reflector.
Data Source
AI summary
A transfer robot system includes a transfer robot configured to transfer a wafer under an operational instruction; a controller configured to output the operational instruction to the transfer robot; a wafer receptacle; and an interferometer. The wafer receptacle comprises a receptacle body having an open front through which an end effector and the wafer pass; a first reflector disposed under a support space; and a first optical element disposed above the support space to face the first reflector, configured to output the light toward the first reflector and receive received light therefrom. The interferometer calculates an optical interference peak, which is generated between the wafer and the first reflector, based on the received light. The controller determines a taught position of the transfer robot based on a variation of the optical interference peak during an operation of the transfer robot.