Specifications
| Measurement mode | Full-angle incidence reflection/scattering mode |
|---|---|
| Probe wavelength | Selectable monochromatic light, 400-700 nm |
| Angular resolution | Within 0.17° |
| Incidence range | -64° to +64° |
| Adjustment axes | X / Y / Z adjustable |
| Probe spot | 1 to 3 μm |
| Polarization | Any polarization angle |
| Sample stage | Customizable automatic scan stage |
Overview
Angle-resolved optical scattering metrology is a non-contact optical measurement system for films, gratings, nanowires and periodic microstructures. The instrument collects reflection and scattering signals across wavelengths, incidence angles and polarization states, and relates the optical response to structural parameters. Combined with RCWA electromagnetic modeling and numerical fitting, it inverts the critical dimensions and optical properties of the sample.
The system measures fast, non-contact and without damage, covering single-layer films, multi-layer films, gratings, nanowires and periodic optical storage structures. Its self-developed fitting algorithm keeps memory footprint low and real-time computation modest, reducing the processing resources needed to invert complex structural parameters.
Measurement Principle
The system uses model-inversion based non-imaging measurement. It does not rely on directly imaging the microstructure, so it can characterize structural parameters below the resolution limit of conventional optical imaging.
- For films: film thickness and multi-layer film thickness can be analyzed
- For gratings and periodic structures: pitch, linewidth and structural height are inverted online
- Wide angle scanning: -64° to +64° incidence, with selectable monochromatic light from 400 to 700 nm
- Any polarization angle and a 1 to 3 μm probe spot for micro-area metrology
RCWA electromagnetic modeling and numerical fitting drive the inversion, returning structural parameters and optical properties.
Applications
- Dielectric film and multi-layer film thickness metrology
- Grating critical parameters: top width, bottom width, pitch, height and sidewall angle
- Nanowire critical parameter measurement
- Element concentration and dimensional measurement in epitaxy and doping processes
- Structural characterization and optical encoding/decoding of 3D nano optical storage
Delivery and Support
The instrument ships with self-developed fitting algorithms and an in-house optical system. The sample stage supports a customized automatic scan module with X / Y / Z adjustability. Seemic provides prototype testing, process matching and on-site integration support, working with customers through metrology data correlation and validation.