Imaging of Metal Ions and Nanoparticles on Structured Silicon Surface Using Laser Ablation-Inductively Coupled Plasma-Mass Spectrometer for Contamination Control in Semiconductor Manufacturing Process

In this study, the imaging of metal ions and nanoparticles deposited on a structured silicon surface was investigated using a laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). For application, 8 × 8 Petri-dish pillars, each with a diameter of 250 μm and height of 300 μm, were constructed on a silicon wafer. The etched pillar surface took a droplet of approximately 4.3 nL aqueous solution from a capillary tip through the surface-liquid attraction. The dissolved materials were found at the intersecting edge of pillar bottom after evaporation, and their positions were matched with the peaks of elements in the mass spectrum for imaging. Results suggest that the trace contaminants in the cleaning solution are gathered at the intersecting edges of the patterned wafer, and the multi-elemental images of the contaminants can be successfully obtained using LA-ICP-MS.