Sample preparation for total reflection X-ray fluorescence analysis using resist pattern technique

Abstract

A circular resist pattern layer with a diameter of 9mm was prepared on a glass substrate (26mm×76mm; 1.5mm thick) for total reflection X-ray fluorescence (TXRF) analysis. The parallel cross pattern was designed with a wall thickness of 10μm, an interval of 20μm, and a height of 1.4 or 0.8μm. This additional resist layer did not significantly increase background intensity on the XRF peaks in TXRF spectra. Dotted residue was obtained from a standard solution (10μL) containing Ti, Cr, Ni, Pb, and Ga, each at a final concentration of 10ppm, on a normal glass substrate with a silicone coating layer. The height of the residue was more than 100μm, where self-absorption in the large residue affected TXRF quantification (intensity relative standard deviation (RSD): 12–20%). In contrast, from a droplet composed of a small volume of solution dropped and cast on the resist pattern structure, the obtained residue was not completely film but a film-like residue with a thickness less than 1μm, where self-absorption was not a serious problem. In the end, this sample preparation was demonstrated to improve TXRF quantification (intensity RSD: 2–4%).