Meaning
High-resolution surface profiling is achieved by scanning a sharp mechanical probe across a sample to detect atomic-scale forces. In atomic force microscopy, this deflection of a cantilever is tracked by a laser to map three-dimensional topography. The technique resolves sub-nanometer features on semiconductor wafers and sensor substrates.
Surface Evaluation
Characterization of substrate roughness at the sub-nanometer level is essential before depositing thin films for high-frequency radio boards. Roughness metrics from atomic force microscopy ensure that copper traces on low-loss laminates will exhibit low signal attenuation. Technicians use these measurements to qualify wafer polishing steps, where a single scan over a ten-micrometer square can reveal micro-voids or scratches that threaten the integrity of subsequent metal layers.
This detailed evaluation provides statistical data on peak-to-valley heights and root-mean-square roughness.
Interface Integrity
Adhesion of metal contacts on silicon depends on localized surface energy and cleanliness. Measuring adhesion forces directly at the nanoscale prevents mechanical failures in RF switches. The probe tips can also measure local stiffness variations to identify material changes.
Scanning Resolution
Spatial resolution of the tip determines the smallest defects that can be resolved. Cantilever geometry is selected based on the required aspect ratio of trenches and vias. This limit dictates the boundary of measurement accuracy.
