To achieve the future goals for logic device dielectric film thickness and composition metrology, a set of well-characterized calibration reference material standards are needed for validating real-time diagnostic techniques used during production. However, there are only a finite number of techniques capable of providing the desired information within this thickness range. Furthermore, the techniques available can disagree on the absolute measured film thickness by an amount that is greater than their respective measurement uncertainty. It is evident that more information is needed to establish a measurement technique capable of satisfying this requirement for the ULSI semiconductor manufacturing industry. A promising technique for characterizing ultrathin films is grazing incidence x-ray photoelectron spectroscopy (GIXPs). GIXPS utilizes the dependence on the material properties of the film, along with the incident angle of the xrays to control the electric field penetration into the sample. By varying the angle of incidence from zero to some value slightly greater than the angle for total x-ray external reflection, it is possible to nondestructively probe the nature of the film depth profile. The desired physical properties, such as film profile, density and thickness, are extracted by constructing a model of the film structure and comparing the measured angle-dependent photoemission spectrum to the calculated spectrum. The measured dielectric thin film thickness and the film depth profile from a diverse group of silcon oxynitride samples in the range of 2 nm to 5 nm will be discussed. In addition, challenges associated with the dependence of the technique upon various fundamental materials parameters will be addressed.
Conference Dates: June 26-29, 2000
Conference Location: -1
Conference Title: Characterization and Metrology for ULSI Technology Conference
Pub Type: Conferences
characterization of Silicon-Oxynitride, dielectric thin films, x-ray