BF-DIC Inspection System with Radial and Tangential Beam Scanning
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Solution Overview
Problem
The semiconductor industry faces challenges in accurately measuring and controlling substrate flatness and edge roll-off (ERO) in wafer processing, which can lead to substrate breakage and affect the production of nanometer-scale electronic devices, due to the limitations of existing inspection techniques.
Innovation Solution
A bright-field differential interference contrast (BF-DIC) system is enhanced to provide high accuracy inspection by creating beams with specific cross-sections and displacements to determine radial and tangential slopes, allowing for precise measurement of substrate curvature and edge roll-off, and compensating for chucking distortions to assess substrate shape and topography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional inspection techniques are used to measure substrate flatness and edge roll-off, then the measurement process is simple, but the measurement precision is insufficient for nanometer-scale deviations
Solution Approach 1:
The inspection system divides the substrate surface into multiple measurement zones (central region and edge regions) and uses multiple beams arranged in specific patterns to measure each zone. This segmentation allows the system to achieve high measurement precision for nanometer-scale deviations while managing device complexity through modular beam configuration
Solution Approach 2:
The system transitions from conventional two-dimensional surface measurement to three-dimensional topographic measurement by incorporating height information through interferometric techniques. This dimensional enhancement enables precise measurement of substrate flatness and edge roll-off profiles, achieving the required measurement precision for nanometer-scale deviations
2Manufacturing precision
If multiple beams with different cross-sections and displacements are used to determine radial and tangential slopes, then the measurement accuracy of substrate curvature and edge roll-off is improved, but the device complexity increases
Solution Approach 1:
The inspection system applies different beam characteristics (round and elliptical cross-sections, different displacements) to different measurement locations on the substrate. Central regions use one beam configuration while edge regions use another, optimizing measurement precision for local topographic features and achieving precise edge roll-off control
Solution Approach 2:
The multi-beam inspection system is designed to perform multiple measurement functions simultaneously: determining radial slopes, tangential slopes, substrate curvature, and edge roll-off profiles using the same set of beams. This multi-functionality improves manufacturing precision while minimizing the increase in device complexity by avoiding separate measurement systems
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 enhanced BF-DIC system achieves sub-nanometer surface height resolution, enabling accurate characterization and monitoring of wafer processes, such as CMP, and improving the productivity and quality of wafer production by reducing substrate breakage and ensuring precise edge profile control.
Implementation Method 1
bright-field differential interference contrast (BF-DIC) system
Data Source
AI summary
A method of providing high accuracy inspection or metrology in a bright-field differential interference contrast (BF-DIC) system is described. This method can include creating first and second beams from a first light beam. The first and second beams have round cross-sections, and form first partially overlapping scanning spots radially displaced on a substrate. Third and fourth beams are created from the first light beam or a second light beam. The third and fourth beams have elliptical cross-sections, and form second partially overlapping scanning spots tangentially displaced on the substrate. At least one portion of the substrate can be scanned using the first and second partially overlapping scanning spots as the substrate is rotated. Radial and tangential slopes can be determined using measurements obtained from the scanning using the first and second partially overlapping scanning spots. These slopes can be used to determine wafer shape or any localized topography feature.