Acoustic Wave Overlay Error Determination in Semiconductor Fabrication
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Solution Overview
Problem
Current semiconductor fabrication techniques face challenges in achieving precise alignment of patterned layers, as existing alignment methods using overlay marks are not perfect and lack improved accuracy.
Innovation Solution
The use of acoustic wave transmission and reception technology, where overlay marks on different layers transmit or reflect acoustic waves, allowing for detection of alignment errors by analyzing the nature of the waves, enabling more precise layer alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional overlay marks are used for alignment, then the alignment process is simple, but the alignment precision is insufficient
Solution Approach 1:
The patent replaces traditional optical/mechanical overlay mark systems with an acoustic wave-based measurement system. Acoustic waves are transmitted through the substrate and overlay marks, and the transmitted wave characteristics are analyzed to determine alignment precision, thereby achieving higher measurement precision while maintaining manageable system complexity
Solution Approach 2:
The patent introduces acoustic waves as an intermediary medium to measure overlay mark alignment. The acoustic waves interact with the overlay marks and substrate, carrying information about their relative positions, which is then extracted to determine alignment precision without requiring direct visual or mechanical contact
2Manufacturing precision
If overlay marks are used for layer alignment, then the process is straightforward, but the alignment accuracy is not perfect
Solution Approach 1:
The patent substitutes traditional visual or mechanical detection methods with acoustic wave transmission and analysis. By measuring changes in acoustic wave characteristics as they pass through misaligned overlay marks, the system can detect and quantify alignment errors with high precision
Solution Approach 2:
The patent utilizes changes in acoustic wave parameters (such as transmission intensity, phase, or frequency) that occur when acoustic waves pass through misaligned overlay marks. These parameter changes serve as indicators of alignment errors, enabling precise measurement of layer alignment accuracy
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 method provides improved alignment accuracy by analyzing the characteristics of acoustic waves to determine alignment errors, enhancing the precision of semiconductor fabrication processes.
Implementation Method 1
with an acoustic transmitter device disposed within the overlay mark region, transmitting an acoustic wave across both the first periodic structure and the second periodic structure
Implementation Method 2
with an acoustic wave receiver device, detecting the acoustic wave
Data Source
AI summary
A method includes forming a first material layer on a semiconductor wafer, the first material layer comprising a first periodic structure within an overlay mark region of the semiconductor wafer and forming a second material layer on the semiconductor wafer, the second material layer comprising a second periodic structure in the overlay mark region. The method further includes with an acoustic transmitter device disposed within the overlay mark region, transmitting an acoustic wave across both the first periodic structure and the second periodic structure. The method further includes, with an acoustic wave receiver device, detecting the acoustic wave and determining an overlay error between the first material layer and the second material layer based on the acoustic wave as detected by the acoustic wave receiver device.