EpiX®
Comprehensive 2D optical wafer mapping for advanced compound semiconductor manufacturing.
EpiX® mapping stations provide fast, non-contact 2D measurement of critical optical wafer properties. By combining white light reflectance, photoluminescence and wafer bow mapping in one platform, EpiX® delivers the spatial insight needed to qualify complex epi-stacks and keep high-volume lines in control.
What is EpiX®?
EpiX® is LayTec’s modular wafer mapping station for ex-situ optical characterization of compound semiconductor and related wafers. An XY mapping stage is combined with UV–VIS–NIR spectroscopic reflectance and photoluminescence metrology, enabling dense 2D maps of thickness, composition and luminescence parameters across the full wafer – all by non-contact optical measurements.
Optimized mechanics, optics and signal processing result in:
Very high absolute accuracy
Excellent signal-to-noise ratio
Superior 2D measurement uniformity across the wafer
Short measurement times suitable for production
The high spectral quality enables advanced analyses such as multi-layer fits, e.g., for GaN HEMT wafers, multiple-peak analysis, precise composition measurements and detailed VCSEL stop-band and cavity-dip evaluations.
Key benefits at a glance:
Full-wafer visibility – 2D maps of thickness, composition, bow and luminescence parameters across the entire wafer surface
Higher yield and tighter specs – quickly identify non-uniformities, drifts and excursions before they impact device performance
Production-ready throughput – cassette-to-cassette automation (EpiX® C2C) with optimized recipes for high-volume lines
R&D flexibility – manual configurations for research and pilot lines using the same analysis methods as production
Robust, upgradeable platform – modular hardware and software to adapt to new materials, device concepts and wavelength ranges
EpiX® is used across a wide range of compound semiconductor and optoelectronic processes, including:
GaN power electronics
2D maps of AlGaN barrier composition and thickness in D-Mode and E-Mode GaN-on-Si power device wafers
Measurement of p-GaN thickness and total stack thickness
Optional mapping of wafer bow and yellow PL for additional process insight
InP-based optoelectronics
PL mapping in the NIR range for InP-based laser and detector structures
2D profiles of peak wavelength, intensity and other luminescence parameters linked to composition and layer quality
LEDs, µLEDs and laser structures
Combined WLR and PL mapping for LED and laser wafers
2D maps of peak, centroid and dominant wavelength, intensity and spectral width
Thickness and total stack analysis where reflectance is configured
VCSEL wafers
Absolute reflectance mapping for stop-band (SB) and cavity-dip (CD) analysis
Extraction of SB center wavelength, width and amplitude
Detailed CD center wavelength, width and area for die-level pass/fail classification
Custom materials and layer stacks
Configurable spectral range (UV to NIR) and laser wavelengths
Support for a wide range of epi-stacks and layer systems, including custom stacks in R&D and pilot lines
Fully automated wafer mapper with wafer handler and cassette-to-cassette feature
Combined white light reflectance and photoluminescence mapping
Wavelength range and PL-laser wavelength customizable
PL laser controller with up to 4 wavelengths
Automated yield analysis
Further metrology methods and components upon request
Integrated analysis features such as:
VCSEL stop band and Cavity dop position/width/height
AlGaN barrier composition and thickness of E-Mode and D-Mode GaN-on-Si power device wafers
Single layer, multiple layer and substrate thickness and composition fits
Multiple-peak analysis
Total thickness variation
C2C features:
Wafer size 3” – 200mm (300mm option available)
Open cassette, SMIF and FOUP load ports
Pre-aligner
Wafer ID reader
Fan-Filter-Units
Features
Connected Metrology®
LayTec Connected Metrology® connects in-situ and ex-situ measurements along the manufacturing chain to improve process control for increasingly complex layer stacks. In a typical frontend production line, wafers are measured three or more times with LayTec systems – and the combined wafer history improves downstream analysis and decisions.
A typical frontend workflow
Epitaxy (in-situ): EpiCurve® TT
Measures thickness and composition of multiple layers in real time, including radial distribution.Wafer mapping (ex-situ): EpiX® C2C
Creates full 2D wafer maps to characterize homogeneity of thickness, composition and other key wafer properties.Plasma etch (in-situ): Etchpoint®
Performs in-situ thickness monitoring and end-point detection during etching.
Why it matters: By combining measurements across steps, Connected Metrology® enables tighter control, better root-cause analysis, and determination of critical layer parameters in complex structures, down to die-level.
Comprehensive optical wafer mapping - combined white light reflectance, photoluminescence and bow
EpiX® mapping stations can be equipped with:
White light reflectance (WLR) for spectral analysis of layer thicknesses and compositions as well as total stack thicknesses.
Photoluminescence (PL) for bandgap-related parameters such as peak wavelength, composition, intensity and line shape.
Wafer bow metrology for curvature and strain monitoring
The spectral range and PL laser wavelength can be configured to your material system, with options for multiple laser wavelengths and extended UV or NIR ranges. This allows EpiX® to be tuned for GaN power, InP optoelectronics, LEDs/µLEDs, VCSELs and many other applications.
Optimized for production and R&D EpiX® C2C – high-throughput cassette-to-cassette mapping
For industrial production lines, the fully automated EpiX® C2C configuration offers:
Cassette-to-cassette wafer handling for common wafer sizes
Support for open cassette, SMIF and FOUP load ports
Pre-aligner and wafer-ID reader for robust automation
Fan-filter units and cleanroom-compatible design
High-throughput mapping recipes with dense sampling (tens of thousands of spectra per wafer)
EpiX® C2C is ideal for routine process qualification, SPC and release of epi-wafers in VCSEL, laser, LED/µLED and GaN-on-Si power lines.
Manual EpiX® mapping stations – flexibility for labs
The manual EpiX® configurations provide the same optical performance and analysis capabilities in a more flexible setup for:
Universities and research institutes
Pilot and development lines
Process and device R&D teams
This makes it easy to transfer recipes and evaluation methods from development to production.
Integrated software and automated data analysis
EpiX® integrates data acquisition and analysis in a single software environment:
Automated fitting of single-layer, multi-layer and substrate thickness
Determination of composition and other derived parameters
Multiple-peak and DBR/VCSEL analysis routines
Wafer-level and die-level statistics, including pass/fail maps
Recipe-based measurement and evaluation for reproducible results
This enables fast routine use on the fab floor while still providing deep analysis capabilities for engineering teams.
Modular Design
The basic design feature of EpiX® mapping stations is modularity and customizability in hardware and software. This is key for industrial customers introducing new processes and requiring extended measurement capabilities as well as academic customers regularly adjusting their research projects to new materials and latest nano-science concepts. Hence, EpiX is designed as a long-lasting workhorse with multiple upgrade options: more optical heads (wafer bow, reflectance-anisotropy, sheet-resistance, wafer thickness, optical transmission), extended wavelength range, software interfaces (e.g. for user-owned spectral analysis libraries) and for using in-situ data measured during epitaxy in center of wafer as starting point for post-epi 2D mapping analysis.
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