AFM Monolayer Defect Detection Using Ultrasonic Contact Stiffness
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Solution Overview
Problem
Conventional methods for manufacturing semiconductor elements face challenges in detecting defects in self-assembled monolayers and directed self-assembled layers, which are prone to defects such as pinholes and delamination, affecting the manufacturing process.
Innovation Solution
A method combining atomic force microscopy (AFM) with ultrasonic force microscopy (UFM) or heterodyne force microscopy (HFM) to simultaneously perform surface topography mapping and binding strength measurements, using a transducer to apply an acoustic vibration signal and analyze output signals for defect detection and subsurface elasticity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional inspection methods are used for self-assembled monolayers, then the manufacturing process remains simple, but defect detection accuracy is insufficient
Solution Approach 1:
The patent combines atomic force microscopy (AFM) with ultrasonic force microscopy (UFM) to create an integrated inspection system. The AFM probe integrates both topography sensing and ultrasonic vibration capabilities, allowing simultaneous acquisition of surface morphology and subsurface defect information through a single measurement system rather than separate inspection devices.
Solution Approach 2:
The patent applies ultrasonic vibration to the AFM probe tip to enable detection of subsurface defects and binding strength. By mechanically vibrating the probe at ultrasonic frequencies, the system can detect variations in contact stiffness and elasticity that indicate defects beneath the self-assembled monolayer surface, which conventional static AFM cannot detect.
2Reliability
If detailed defect detection is performed on self-assembled monolayers, then manufacturing quality improves, but inspection time increases
Solution Approach 1:
The patent enables continuous scanning and detection by maintaining constant ultrasonic vibration during the AFM scanning process. The probe continuously vibrates at ultrasonic frequencies while moving across the surface, allowing simultaneous topography mapping and defect detection without interrupting the measurement flow, thus reducing total inspection time compared to sequential measurement methods.
Solution Approach 2:
The ultrasonic vibration is applied continuously throughout the scanning process rather than being applied after topography measurement. This preliminary and continuous application of vibration allows defect detection to occur concurrently with surface mapping, eliminating the need for separate post-processing inspection steps.
3Productivity
If only surface topography is mapped, then the inspection process is fast, but subsurface defects and binding strength cannot be detected
Solution Approach 1:
The patent merges topography mapping and subsurface defect detection into a single simultaneous measurement process. The AFM system collects both surface height information and ultrasonic contact stiffness data during the same scanning operation, eliminating the need for separate measurement passes and achieving both surface and subsurface characterization in one go.
Solution Approach 2:
By applying ultrasonic vibration to the probe, the system gains sensitivity to subsurface mechanical properties. The vibration causes the probe to respond differently to variations in contact stiffness caused by subsurface defects or weak binding, enabling detection of these features during the same scanning process used for topography mapping.
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
Enables accurate and time-efficient detection of defects in self-assembled monolayers, allowing integration into high-throughput manufacturing processes for semiconductor elements.
Implementation Method 1
applying an acoustic vibration signal to the semiconductor element
Implementation Method 2
surface defects are detected by the monitoring of the probe tip motion that enables to map the surface of the semiconductor element
Implementation Method 3
mapping a position dependent contact stiffness indicative of subsurface elasticity
Data Source
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AI summary
The present document relates to a method of performing defect detection on a self-assembled monolayer of a semiconductor element or semi- manufactured semiconductor element, using an atomic force microscopy system. The system comprises a probe with a probe tip, and is configured for positioning the probe tip relative to the element for enabling contact between the probe tip and a surface of the element. The system comprises a sensor providing an output signal indicative of a position of the probe tip. The method comprises: scanning the surface with the probe tip; applying an acoustic vibration signal to the element; obtaining the output signal indicative of the position of the probe tip; monitoring probe tip motion during said scanning for mapping the surface of the semiconductor element, and using a fraction of the output signal for mapping contact stiffness indicative of a binding strength.