Rapid XPS image acquisition using SnapMap

Significance of the Topic

Surface chemical imaging at high spatial resolution is critical for applications ranging from materials science to quality control in manufacturing. Rapid acquisition of XPS images enables analysts to locate and characterize microscale features efficiently, improving throughput and data quality in analytical workflows.

Objectives and Study Overview

This application note describes the implementation of SnapMap technology in Thermo Scientific Nexsa™ and K-Alpha™ XPS systems. The goal is to demonstrate how synchronized stage rastering and snapshot spectrum acquisition allow the generation of high-resolution, large-area chemical maps within minutes, and to outline the subsequent data processing capabilities.

Methodology

SnapMap works by moving the sample stage beneath a fixed, focused X-ray beam so that each pixel corresponds to a discrete XPS spectrum. The spectrometer collects these spectra continuously as the stage follows a predefined raster pattern. Key steps include:

• Selection of element-specific or survey peaks (e.g., O1s) for initial mapping.
• Synchronized stage motion and data capture to ensure uniform pixel definition across large areas.
• Use of small X-ray spots (down to 10 µm) to achieve detailed imaging of fine features.

Used Instrumentation

The study utilizes:

• Thermo Scientific Nexsa™ and K-Alpha™ XPS systems with reflex optics.
• Micro-focused X-ray source capable of 10 µm spot size.
• Thermo Scientific™ MAGCIS™ ion source for optional depth profiling.
• Avantage data processing software (Thermo Fisher Scientific).

Main Results and Discussion

SnapMap generates chemical images in which each pixel contains a full XPS snapshot spectrum. Highlights include:

• Rapid mapping of areas up to several millimeters with consistent resolution determined by the X-ray spot.
• Identification of surface features as small as 10 µm that may be invisible under optical inspection.
• Overlay of multiple elemental maps processed by principal component analysis (PCA), target factor analysis (TFA) or non-linear least squares fitting (NLSF) to reveal compositional distributions.

Benefits and Practical Applications

SnapMap offers several practical advantages:

• Accelerated alignment of micro-features prior to high-resolution point analysis.
• Efficient survey of large sample areas without repeated manual targeting.
• Data-rich imaging that supports both qualitative identification and quantitative analysis through advanced processing.

Future Trends and Opportunities

Emerging directions include:

• Integration of machine learning algorithms for automated feature recognition in SnapMap data.
• Real-time feedback loops to adjust acquisition parameters dynamically.
• Expansion of rapid imaging approaches to include depth profiling and three-dimensional tomography.

Conclusion

SnapMap technology transforms XPS imaging by combining stage rastering, snapshot spectrum acquisition, and powerful data processing in a streamlined workflow. This approach enables rapid, high-resolution chemical mapping of large sample areas and precise targeting of microscale features, enhancing productivity in surface analysis laboratories.

Reference

• Robin Simpson, Application Note AN52330, Thermo Fisher Scientific, 2018.