Shallow As dose measurements of patterned wafers with secondary ion mass spectrometry and low energy electron induced x-ray emission spectroscopy

Abstract

Secondary ion mass spectrometry (SIMS) and low energy electron induced x-ray emission spectroscopy (LEXES) are both well established technologies. SIMS tools are the ultimate reference for depth profiling and direct measurement of dopants with highest sensitivity and dynamic range. The LEXES-based shallow probe is a versatile, sensitive, in-line metrology tool for thin layer elemental composition and dopant dosimetry in semiconductor production. In this contribution, the ability of LEXES and SIMS techniques to differentiate nominal dose differences among three different 300mm patterned wafers are compared. In each die, several test pads were available for dose measurements. Five neighboring dies were measured by LEXES and afterward by SIMS. The repeatability measurements of both techniques (<0.5%) is suitable to determine dose nonuniformity from die to die and to discriminate nominal dose between wafers as small as 3%.