Document Metadata & Cleanroom Protocols
- Document ID:
SOP-MET-2021-16(Rev 2.0) - Lead Specialist / Author: Kadeem Manning (Tier II Specialist)
- Facility: Thin-Film & Dielectric Metrology Lab (ISO 6 / Class 1000)
- Compliance: ALCOA+ / NIST Traceable Standards
- Official PDF: Download Official Metrology SOP PDF
1. Characterization Phases & Measurement Matrix
[Fabricated Wafer / Substrate]
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▼ ▼ ▼
[Phase 1] [Phase 2] [Phase 3]
Spectroscopic Stylus Profilometry Dual-Polarity 4-Point Probe
Ellipsometry (Physical Step Height) Sheet Resistance ($R_s$)2. Multi-Phase Metrology Workflow
Phase 1: Spectroscopic Ellipsometry (Optical Thickness & Refractive Index)
- Initialize spectroscopic ellipsometer light source; execute baseline calibration on standard $100\text{ nm } \text{SiO}_2/\text{Si}$ calibration wafer.
- Verify psi ($\Psi$) and delta ($\Delta$) root-mean-square error (RMSE) $< 1.5$.
- Position test sample on vacuum chuck; acquire spectral scan across $\lambda = 380\text{ nm} - 1000\text{ nm}$ at angles of incidence $\theta = 65^\circ, 70^\circ, 75^\circ$.
- Fit Cauchy/Tauc-Lorentz dielectric models to resolve film thickness $d$ and refractive index $n(\lambda)$.
Phase 2: Dual-Polarity 4-Point Probe (Sheet Resistance & Conductivity)
- Clean tungsten carbide probe tips with electronic-grade Isopropanol (IPA).
- Position probe head on substrate center, applying regulated $100\text{ g}$ contact force.
- Apply forward ($+I$) and reverse ($-I$) DC current ($1.0\text{ mA} - 10.0\text{ mA}$) to eliminate thermal thermoelectric EMF voltage offsets: $$R_s = \left(\frac{\pi}{\ln 2}\right) \cdot \left(\frac{V_+ - V_-}{2I}\right) \cdot F(t/s)$$
- Compute bulk electrical conductivity: $$\sigma = \frac{1}{R_s \cdot d}$$
Phase 3: Microwave Dielectric Permittivity Extraction (1–20 GHz)
- Perform 2-port SOLT (Short-Open-Load-Thru) calibration on Vector Network Analyzer (VNA).
- Connect Substrate Integrated Waveguide (SIW) planar resonator fixture.
- Measure scattering parameters ($S_{11}, S_{21}$) and calculate complex relative permittivity: $$\varepsilon_r = \varepsilon_r’ - j\varepsilon_r”$$