Vortex Pattern Measurement Target for Overlay Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In semiconductor manufacturing, achieving precise alignment between successive layers of material on silicon wafers is crucial to prevent misalignment issues such as short circuits and connection failures, which impact fab yield and profit margins.
Innovation Solution
The implementation of a measurement target with a specific pattern design, comprising a central part and noncentral parts arranged in a vortex pattern, allows for enhanced sensitivity in detecting overlay shifts between layers, thereby improving alignment accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional alignment methods are used, then manufacturing process is simple, but alignment precision between layers deteriorates
Solution Approach 1:
The measurement target is segmented into multiple distinct parts: a first pattern on the first layer and a second pattern on the second layer. Each pattern can be independently designed and optimized for its specific function, allowing the overall system to achieve high measurement precision without requiring the entire manufacturing process to become complex
Solution Approach 2:
The measurement target acts as an intermediary element between the two layers being aligned. By providing specific patterns on each layer that can be optically detected, it mediates the alignment process between successive layers without requiring direct mechanical intervention or complex alignment mechanisms
2Manufacturing precision
If overlay control is not implemented, then manufacturing process is faster, but alignment accuracy deteriorates
Solution Approach 1:
The measurement target patterns are prepared in advance on both layers during the manufacturing process. This preliminary action allows for quick optical detection and measurement of overlay alignment without requiring complex real-time adjustments, thereby maintaining high alignment accuracy while minimizing measurement time
Solution Approach 2:
The patent replaces mechanical alignment methods with optical detection methods. By using optical patterns that can be detected and measured non-contactively, the system achieves high overlay alignment accuracy without the time-consuming mechanical measurements and adjustments
3Measurement precision
If simple pattern design is used, then manufacturing is easier, but sensitivity to overlay shifts deteriorates
Solution Approach 1:
The measurement target employs local quality by designing specific patterns with particular geometric properties at specific locations. The first and second patterns are designed with characteristics that maximize their sensitivity to overlay shifts in their respective local contexts, allowing high measurement precision without requiring the entire device structure to become complex
Solution Approach 2:
The patent utilizes optical contrast (analogous to color changes) between different patterns and layers to enhance detection sensitivity. The patterns are designed to create distinct optical signals that are highly sensitive to alignment shifts, enabling precise measurement without complex physical structures
Data Source
AI summary
Semiconductor device is provided. The semiconductor device includes a first pattern and a second pattern. The first pattern includes a first central part and a plurality of first noncentral parts surrounding the first central part and spaced apart from each other. The second pattern is at a second layer over the first layer of the substrate and at least partially overlapping the first pattern along a first direction passing through the first layer and the second layer. The plurality of first noncentral parts define a vortex arrangement.