Sidewall Scanning Probe Microscopy for Narrow 3D Structures
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Solution Overview
Problem
Conventional scanning probe microscopy methods are inefficient and inaccurate for measuring the topography of narrow and high aspect-ratio structures, particularly those with negative slopes, due to limitations in probe access and complex parameter tuning, and fail to provide comprehensive three-dimensional mapping.
Innovation Solution
A non-oscillatory scanning probe microscopy method that allows simultaneous measurement of side wall topographies in multiple orthogonal directions using a probe tip that establishes contact with the side wall, determining lateral positions through relative motion between the probe and substrate carrier, facilitated by additional actuators and sensors for precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If oscillatory imaging methods with resonant frequency driving are used, then measurement speed and accuracy are improved, but the operational footprint of the tip is enlarged which limits access to narrow trenches and openings
Solution Approach 1:
The patent applies oscillatory motion to the probe tip in the lateral direction (parallel to substrate surface) during measurement. The probe tip is oscillated while maintaining contact with the sidewall, enabling accurate topography measurement of narrow structures without requiring the tip to be driven at resonant frequency, thus avoiding enlargement of operational footprint.
2Device complexity
If conventional tilted probe measurement is used, then device complexity is reduced, but measurement of overhanging side walls with negative slope fails and productivity is reduced due to requiring four separate measurements
Solution Approach 1:
The patent employs dynamic oscillatory motion of the probe tip in the lateral direction while maintaining contact with the sidewall. This dynamic approach enables the probe to follow the contours of overhanging surfaces and negative slopes that static tilted probe methods cannot capture, achieving complete 3D mapping in a single measurement pass.
Solution Approach 2:
The patent adds lateral oscillatory motion (parallel to substrate surface) to the conventional measurement approach. This additional dimensional motion enables the probe to access and measure sidewalls with negative slopes and overhanging features, transforming an otherwise impossible measurement into a feasible single-pass operation.
3Productivity
If oscillatory imaging methods are used, then measurement speed is improved, but only one orthogonal direction parallel to the surface can be measured requiring eight parameters tuning upon probe exchange
Solution Approach 1:
The patent measures topography in both X and Y directions (both orthogonal directions parallel to substrate surface) simultaneously using the same oscillatory measurement procedure. The probe tip oscillates laterally while scanning, enabling comprehensive 3D mapping of sidewalls in multiple directions without requiring separate measurement sequences or extensive parameter re-tuning during probe exchange.
Data Source
AI summary
The present document relates to a method of measuring a topography of a side wall of a structure on a surface of a substrate using a scanning probe microscopy system. The system comprises a probe with a probe tip, and the substrate is supported on a substrate carrier. The method includes performing a measurement at a measurement point, which includes the steps of: moving the probe and the substrate carrier relative to each other to approach the probe tip towards the surface in a Z-direction perpendicular to the substrate surface; determining that the probe tip is located adjacent the side wall; establishing contact between the probe tip and the side wall; and obtaining a lateral position of the probe tip while in contact with the side wall, to determine a current position on the side wall. The step of establishing contact comprises a step of moving the probe tip relative to the substrate carrier in at least one lateral direction transverse to the Z-direction, by applying a non-oscillatory motion on the substrate carrier or the probe. The document further relates to a scanning probe microscopy device.