Wafer Pre-Alignment Device Using Optical Position Detection
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Solution Overview
Problem
Conventional TSV-wafer pre-alignment methods are inefficient, lack accuracy, and are vulnerable to human error, and cannot automate the handling of wafers from various processes, including warped, ultra-thin, and Taiko wafers, due to limitations in centering and orientation.
Innovation Solution
A wafer pre-alignment device with a first unit for rotating or moving the wafer and a second unit for translating it, equipped with a position detector using a light source, image sensor, and lens to adjust the wafer's position based on captured light beam information, allowing for precise centering and orientation of TSV, warped, ultra-thin, and Taiko wafers, and capable of handling different types of wafers through reflective and catadioptric optical systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual alignment methods are used for TSV wafers, then the pre-alignment process can be performed, but the efficiency is low and pre-alignment accuracy is low and vulnerable to human error
Solution Approach 1:
The patent replaces manual mechanical alignment operations with an automated optical measurement system. A light source illuminates the wafer, and a camera captures images of wafer features (notches, edges, marks) to automatically determine position and orientation, eliminating manual measurement errors and提高效率
Solution Approach 2:
The system enables self-alignment by using the wafer's own features (notches, edges, or fabricated marks) as reference points for automatic positioning. The wafer itself provides the alignment information needed, without requiring external manual intervention or separate alignment tools
2Extent of automation
If conventional pre-alignment methods are used, then alignment can be performed, but automation is not allowed and human disturbance vulnerability increases
Solution Approach 1:
The patent replaces manual alignment operations with an automated optical measurement and control system. The system uses a light source, camera, and image processing algorithms to automatically detect wafer features and calculate alignment parameters, eliminating human intervention and associated variability
Solution Approach 2:
The system implements closed-loop feedback by capturing wafer images, analyzing feature positions, calculating alignment deviations, and using this information to drive automated adjustment mechanisms that correct the wafer position and orientation
3Adaptability or versatility
If a single pre-alignment device is used for various wafer types, then device versatility is improved, but centering and orientation challenges increase
Solution Approach 1:
The patent designs a universal pre-alignment device that can handle multiple wafer types (TSV wafers with notches, warped wafers, ultra-thin wafers, Taiko wafers) using the same optical measurement system. The system automatically adapts to different wafer geometries by detecting their specific features (notches, edges, marks) and applying appropriate alignment algorithms
Solution Approach 2:
The system handles different wafer types by adjusting measurement and alignment parameters based on detected wafer characteristics. The optical system can accommodate variations in wafer thickness, curvature, and feature geometry by modifying focus, illumination, and image processing parameters
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 device achieves higher accuracy and efficiency in wafer centering and orientation, automates the pre-alignment process, and is adaptable to various wafer types by compensating for eccentricity and warpage, improving handling capabilities and reducing human intervention.
Implementation Method 1
a light beam from the light source passes through the wafer, the first chuck and the lens and thereby provides information indicating a position of the wafer relative to the first chuck on to the image sensor
Implementation Method 2
an image sensor disposed above the first chuck... provides information indicating a position of the wafer relative to the first chuck on to the image sensor
Implementation Method 3
a lens disposed under the first chuck, wherein a light beam from the light source passes through the wafer, the first chuck and the lens
Data Source
AI summary
A wafer pre-alignment device is disclosed, including a first unit configured to drive a wafer to rotate or move upward or downward, a second unit configured to drive the wafer to translate, and a position detector including a light source, a lens and an image sensor. A light beam from the light source passes through the wafer and the lens and thereby provides information indicating a position of the wafer to the image sensor. The first unit and the second unit are able to adjust the position of the wafer based on the information obtained by the image sensor. A method for pre-aligning a TSV wafer is also disclosed.