Phosphorus Determination in Borophosphosilicate or Phosphosilicate Glass Films on a Si Wafer by Wavelength Dispersive X-ray Spectroscopy

Abstract

Films of borophosphosilicate glass (BPSG) or phosphosilicate glass (PSG) are deposited on single crystal Si (100) wafers (typically 4 to 6 inches in diameter) by chemical vapor deposition processes during the fabrication of radiation-hardened microcircuits. These films act as insulator and as passivation layers. Since the P content of the glass layer is critical because of fluidity and corrosion problems, careful certification is required. The certification analysis has been accomplished here previously by empirical energy dispersive (ED) X-ray fluorescence (XRF) methods which use a set of expensive and fragile PSG wafer calibration standards. The results obtained were uncertain and the standards were sometimes broken.