Damage-free failure/defect analysis in electronics and semiconductor industries using micro-ATR FTIR imaging

Importance of the Topic

In modern electronics and semiconductor manufacturing, microscopic contamination can halt production, incur high costs and compromise product quality. Rapid, non-destructive identification of particulates and chemical residues is essential for minimizing downtime and ensuring reliable operation of delicate components.

Objectives and Study Overview

This application note examines the use of micro-ATR FTIR imaging to detect and characterize submicron defects on two sample types received from manufacturers:

• An LCD color filter contaminated with microscopic “dust” particles
• A printed circuit board (PCB) bearing unexplained residues

Both samples resisted conventional analytical approaches, prompting evaluation of Agilent’s live FPA imaging technique to pinpoint contamination sources quickly and without damage.

Methodology and Instrumentation

Samples were mounted directly on the motorized microscope stage with no additional preparation. High-resolution chemical images were acquired using:

• An Agilent Cary 620 FTIR microscope equipped with a 64×64 pixel Focal Plane Array detector
• An Agilent Cary 660 FTIR spectrometer coupled to a micro-Germanium Attenuated Total Reflection (ATR) accessory

Key operating parameters:

• Spectral resolution: 8 cm⁻¹
• Wavenumber range: 4000–900 cm⁻¹
• Scans per image: 128
• Spatial resolution: 1.1 µm per pixel
• Field of view: 70×70 µm
• Total spectra collected: 4096
• Acquisition time: approximately 4 minutes

Data processing and spectral searching were performed using Agilent Resolutions Pro software and commercially available and in-house libraries.

Main Results and Discussion

Case 1: LCD Color Filter Contamination
Using live FPA imaging in micro-ATR mode, a 70×70 µm region was mapped at 1.1 µm pixel resolution. False-color chemical images based on absorbance at 1017 cm⁻¹ highlighted individual particles. Spectral matching identified them as polymer spacers dislodged after manufacturing.

Case 2: PCB Surface Defects
A previous attempt with a competing ATR system caused damage due to uncontrolled pressure. Agilent’s live imaging approach prevented sample indentations and generated a chemical image at 1720 cm⁻¹. Rapid library searching confirmed the residues as polyetherimide insufficiently cleaned post-fabrication.

Benefits and Practical Applications

The described micro-ATR FTIR imaging workflow offers:

• Non-destructive analysis of delicate electronic components
• Minimal or no sample preparation
• High spatial resolution down to 2 µm heterogeneities
• Rapid turnaround—full chemical maps in minutes
• Real-time feedback to optimize ATR contact pressure

This approach streamlines failure analysis, reduces costly downtime and accelerates root-cause identification in manufacturing settings.

Future Trends and Potential Applications

Advances in detector sensitivity and ATR crystal design will further enhance chemical contrast and spatial resolution. Integration with automated defect classification and AI-driven spectral interpretation may deliver real-time quality control and inline monitoring in high-volume production lines. Expanding reference libraries to cover emerging materials and contaminants will support broader adoption across semiconductor, display and microelectronic industries.

Conclusion

Micro-ATR FTIR imaging using Agilent’s Cary 620 microscope and live FPA technique provides a damage-free, high-throughput solution for pinpointing submicron defects on sensitive electronic substrates. By delivering spatially resolved chemical information within minutes and eliminating sample damage, this method significantly improves manufacturing efficiency, lowers costs and enhances product reliability.