Semiconductor Alignment Mark for Multi-Layer Defect Inspection
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Solution Overview
Problem
As semiconductor integrated circuits shrink, multi-layer structures pose challenges in layer-to-layer alignment and defect inspection, leading to offset issues due to different coordinate systems used in optical and electrical defect inspections, resulting in poor overlap sensitivity.
Innovation Solution
An alignment mark is created using ion implantation on a semiconductor substrate with a n− well, p+ doping region, and conductive plugs, allowing both optical and electrical defect inspection systems to align to the same reference point, improving coordinate alignment and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If different types of defect inspection systems (optical and electrical) are used for multi-layer structure inspection, then comprehensive defect detection capability is improved, but coordinate offset issues arise due to different coordinate systems, resulting in poor overlap sensitivity
Solution Approach 1:
The alignment mark structure serves multiple functions: it provides a common reference point for both optical defect inspection and electrical defect inspection systems, enabling coordinate alignment between different inspection types while maintaining their respective detection capabilities
Solution Approach 2:
The alignment mark acts as an intermediary reference structure that bridges the coordinate systems of optical and electrical inspection systems, allowing accurate overlay comparison without requiring direct coordination between the two different inspection methodologies
2Measurement precision
If ion implantation processes are used to create the alignment mark, then alignment precision and defect inspection accuracy are improved, but the manufacturing process complexity increases
Solution Approach 1:
The alignment mark fabrication is merged with the existing semiconductor manufacturing process flow by utilizing ion implantation steps that are already part of the standard process, thereby achieving high precision alignment marks without adding significant process complexity
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 alignment mark significantly reduces coordinate offset issues between different defect inspections, enhancing overlap sensitivity to approximately one micron by providing a common reference point for both optical and electrical defect inspections.
Implementation Method 1
an alignment mark fabricated by ion implantation processes
Data Source
AI summary
A defect inspection method is disclosed. A first type defect inspection system is used to perform a first defect inspection by aligning to an alignment mark on a wafer as a reference point for the first defect inspection. A fabrication process is performed on the wafer thereafter, and a second defect inspection is performed by using a second type defect inspection system to align the alignment mark on the wafer as the reference point for the second defect inspection.