Rotary Suction Cup Wafer Alignment for Dynamic Deskew Correction
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Solution Overview
Problem
Existing wafer handling technologies suffer from low accuracy in dynamic deviation correction due to complex processes involving high-precision laser sensors, leading to potential errors and inconsistencies in wafer placement.
Innovation Solution
A method and system for wafer positioning and correction that utilizes real-time data acquisition and calculation of motor rotation angles and optical calibrator shading to determine and correct radius and phase deviations, ensuring accurate placement by using a rotary suction cup connected to a motor and an optical calibrator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two high-precision laser sensors are used for dynamic deviation correction, then measurement precision is improved, but device complexity increases and calibration accuracy decreases due to complicated calculation processes
Solution Approach 1:
The patent extracts and eliminates the complex calculation and calibration processes from the existing two-sensor system. By using a single laser sensor combined with a rotary suction cup mechanism, the system removes the need for simultaneous circular center correction and direction calibration, thereby reducing device complexity while maintaining measurement precision through simplified real-time data acquisition and calculation.
Solution Approach 2:
The patent replaces the mechanical complexity of two high-precision laser sensors with a combination of a single laser sensor and a motor-driven rotary suction cup system. This substitution uses motor control and optical measurement to achieve the same correction function with reduced mechanical complexity and easier calibration.
2Measurement precision
If complex calibration and calculation processes are used, then measurement precision is improved, but loss of time increases due to simultaneous circular center correction and direction calibration
Solution Approach 1:
The patent performs preliminary positioning by placing the wafer on the rotary suction cup before the actual measurement and correction process. This preliminary action establishes a stable reference frame and enables sequential processing rather than simultaneous complex calculations, thereby reducing the time required for correction while maintaining calibration accuracy through pre-established geometric relationships.
Solution Approach 2:
The patent skips the time-consuming simultaneous calibration and correction process by using a sequential approach: first acquiring wafer position data through the rotary suction cup mechanism, then calculating deviations, and finally applying corrections. This rushing through the process in discrete steps eliminates the time penalty of simultaneous multi-parameter calibration while preserving measurement precision.
3Productivity
If multiple processes and multiple handling are used for wafer transport, then productivity is improved, but manufacturing precision deteriorates due to wafer deviation from robot finger center
Solution Approach 1:
The patent implements a feedback mechanism where the laser sensor continuously monitors wafer position on the rotary suction cup, and the system automatically calculates and applies corrections based on detected deviations. This closed-loop feedback ensures that even after multiple handling operations, the wafer is dynamically repositioned to the correct location, maintaining manufacturing precision while allowing efficient multi-step transport processes to continue.
Solution Approach 2:
The patent introduces dynamic correction capability through the motor-driven rotary suction cup system that can adjust wafer position in real-time during the transport process. This dynamic adjustment compensates for deviations accumulated during multiple handling operations, ensuring accurate placement without requiring slower, more careful manual positioning at each step, thereby maintaining both productivity and precision.
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
Improves the accuracy of wafer placement by correcting central position radius and phase deviations, ensuring consistent final placement positions and achieving dynamic correction effects.
Implementation Method 1
the optical calibrator shading amount si, and thereby calculating the rotation angle θi of the wafer to be measured and the distance between the edge of the wafer to be measured and the center O of the rotary suction cup ρi
Data Source
AI summary
A semiconductor wafer transfer device has a wafer positioning deskewing method via steps of initially setting parameters for the size of a wafer to be measured; collecting a motor rotational angle initialization settings for the size of the wafer to be measured; collecting motor angle data αi and optical calibrator optical calibrator shading length data si; calculating the wafer turning angle θi and the wafer edge to center of rotation distance data ρi. The distance between the edge of the wafer to be measured and the center of the rotating suction cup is determined to the center of the rotating suction cup is within the specified range.