Phase-Change Wafer Sensor for High-Precision Alignment Detection
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Solution Overview
Problem
Semiconductor substrate processing faces challenges with poor alignment due to mechanical error accumulation, leading to reduced yield, necessitating precise alignment evaluation and control in operations like photolithography and wafer testing.
Innovation Solution
A wafer sensor with a phase change material layer and a wafer alignment system that includes a blocking layer, reflective layer, and metal antennas, utilizing a phase change in the material layer to measure alignment by reflectivity changes, allowing for precise adjustment through a measurement station.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional alignment methods are used, then manufacturing process can proceed, but alignment precision deteriorates due to mechanical error accumulation
Solution Approach 1:
The patent replaces mechanical alignment measurement methods with an optical detection system. A sensor captures optical images of alignment marks on the wafer, and a processor analyzes these images to determine alignment position. This optical system eliminates accumulation of mechanical errors inherent in conventional mechanical alignment methods, providing stable and precise alignment measurements over time.
Solution Approach 2:
The patent creates an optical copy (image) of the alignment marks on the wafer using a sensor. Instead of directly measuring physical positions with mechanical contact, the system captures an optical representation of the alignment marks and processes this image data to determine alignment. This copying approach enables non-contact, high-precision measurement that avoids mechanical error accumulation.
2Measurement precision
If optical detection system is implemented, then alignment precision improves, but device complexity increases
Solution Approach 1:
The alignment detection system is divided into distinct functional modules: a sensor unit for capturing optical images of alignment marks, and a processor unit for analyzing the captured images and determining alignment position. This segmentation allows each module to be optimized independently and simplifies the overall system architecture, making the optical detection system more manageable and implementable despite its enhanced capabilities.
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
Enhances alignment precision by detecting phase changes optically with high sensitivity and spatial resolution, improving yield in semiconductor manufacturing processes.
Implementation Method 1
heating, by the chuck, at least a portion of the phase change material layer to a crystallization temperature or greater
Implementation Method 2
measuring a change in reflectivity of the phase change material layer
Data Source
AI summary
A wafer sensor includes a wafer substrate and a plurality of pixels on the wafer substrate, where each pixel of the plurality of pixels includes a blocking layer, a reflective layer on the blocking layer, a phase change material layer on the reflective layer, and a plurality of metal antennas on the phase change material layer.