Rear Laser Wafer Edge Scanning for Stacked Wafer Alignment
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Solution Overview
Problem
Existing methods for wafer alignment and detection require multiple sensors, leading to interface management and component arrangement challenges, especially when dealing with stacked wafers, and increase the time required for inspection processes.
Innovation Solution
A semiconductor transfer device equipped with a single laser scanner that scans the edges of wafers from the rear, using a detection unit to determine the presence and alignment of wafers by measuring peak distances in predetermined vertical areas, allowing for simultaneous detection of multiple wafers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sensors are used for wafer detection and alignment, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple detection functions (presence detection, alignment detection, and stacking number detection) into a single laser scanner. The laser scanner emits laser beams that reflect off wafer edges, and the reflection amount detection unit processes all detection tasks using one integrated sensor system, eliminating the need for multiple separate sensors and their associated interface management complexities.
Solution Approach 2:
The single laser scanner is designed to perform multiple functions: detecting wafer presence, determining wafer alignment, and counting stacked wafers. By making the laser scanner a multi-functional device that can handle all detection requirements, the system achieves high measurement precision without the device complexity that would result from using multiple specialized sensors.
2Measurement precision
If multiple sensors are installed for each wafer, then wafer alignment detection is improved, but ease of operation deteriorates
Solution Approach 1:
The patent merges all wafer detection operations into a single laser scanner interface. Instead of managing multiple sensor interfaces for different detection tasks, the system uses one unified interface that handles presence detection, alignment detection, and stacking number detection, significantly improving ease of operation while maintaining detection precision.
3Measurement precision
If die-to-die comparison method is used for wafer inspection, then measurement precision is improved, but productivity decreases
Solution Approach 1:
The patent extracts the essential detection information (wafer edge reflection amounts) and processes it directly through calculation units that determine presence, alignment, and stacking number. This eliminates the time-consuming die-to-die comparison process by using a more direct measurement approach that achieves comparable precision faster, thereby improving productivity.
4Device complexity
If a single laser scanner is used for multiple wafers, then device complexity is reduced, but measurement precision may deteriorate
Solution Approach 1:
The laser scanner is designed as a universal detection device that can simultaneously detect multiple wafers at different positions. By equipping the single scanner with multi-functional capabilities and using it in a multi-functional configuration, the system maintains high measurement precision for simultaneous detection of multiple wafers while reducing device complexity.
Solution Approach 2:
The patent detects wafers in the vertical stacking direction by measuring reflection amounts from different height positions. This dimensional approach allows a single laser scanner to detect multiple wafers simultaneously by analyzing reflection data from different vertical levels, maintaining precision without requiring multiple scanners.
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
This solution simplifies the detection process, reduces the number of sensors needed, and decreases the time required for wafer inspection by enabling the use of a single laser scanner to determine the presence and alignment of multiple stacked wafers efficiently.
Implementation Method 1
a laser scanner disposed on a rear side of a mounted wafer and radiating a laser to a portion of an edge of the wafer
Data Source
AI summary
An apparatus and method of detecting a wafer edge using a laser scanner, and a semiconductor transfer device are provided. The apparatus for detecting a wafer edge using a laser scanner includes a laser scanner disposed on a rear side of a mounted wafer and radiating a laser to a portion of an edge of the wafer, and a detection unit receiving an image acquired by the laser scanner and detecting the wafer edge in the image. The detection unit determines whether each wafer is present or aligned according to wafer edges detected in a plurality of wafer areas in the image.