Sweeping-TXRF: A Nondestructive Technique for the Entire Surface Characterization of Metal Contaminations on Semiconductor Wafers

Abstract

We propose a new mode of total reflection X-ray fluorescence (TXRF) analysis called "Sweeping-TXRF" for the characterization of wafer surface contaminations in semiconductor manufacturing. Essentially, Sweeping-TXRF is the mapping of an entire surface with a very short data acquisition time for each individual spot. Sweeping-TXRF provides three-dimensional views for individual elements on a wafer in a very short period of time, a method that had never before been achieved by traditional methods. Dedicated software for this method was developed and tested, and the results are quite promising for routine contamination characterization.Index Terms-Chemical analysis, mapping, nondestructive analysis, total reflection X-ray fluorescence (TXRF).

Intelligent Simultaneous Quantitative Online Analysis of Environmental Trace Heavy Metals with Total-Reflection X-Ray Fluorescence

“…In addition, novel working modes of TXRF for different applications have been developed. The concepts of micro total-reflection X-ray fluorescence (μ-TXRF) [ 49 ] and sweeping total-reflection X-ray fluorescence (Sweeping-TXRF) [ 50 ] have been proposed. Related applications, such as wafer analysis [ 51 ], VLSI micro contamination detection [ 52 ], and the introduction of novel materials in clean-room production [ 53 ], are extended.…”

Trends in total reflection X-ray fluorescence spectrometry for metallic contamination control in semiconductor nanotechnology

“…Very recently, S-TXRF has made its entry in semiconductor applications for research and production [33,92,93]. Along the advantages of S-TXRF is that spatial correlations can be made between contaminants which is very helpful is tracing the source of contaminations.…”

“…The combined presence of elements such as Fe, Cr and Ni in the shape of chuck print-off for example, easily lead to a contact contamination with stainless steel in one of the process tools (Fig. 9b) [33,92,93]. Another advantage is that non-homogeneous contamination problems such as metallic particle issues are discovered much easier.…”

“…Another advantage is that non-homogeneous contamination problems such as metallic particle issues are discovered much easier. Eventually combined with defect review using secondary electron microscopy-energy dispersive X-ray spectrometry (SEM-EDX) this allows also more efficient problem solving [93]. A disadvantage of the S-TXRF method is the loss in detection power of one order of magnitude, inherently related to the shorter spectral acquisition times.…”

“…(b) Resulting contour plots of metal contamination levels of Fe, Ni, Cu and Zn of a wafer loaded upside down in a contaminated process chamber (after Mori et al[93]). …”