US 10,770,362 B1 · Dispersion model for band gap tracking

Abstract

Methods and systems for determining band structure characteristics of high-k dielectric films deposited over a substrate based on spectral response data are presented. High throughput spectrometers are utilized to quickly measure semiconductor wafers early in the manufacturing process. Optical models of semiconductor structures capable of accurate characterization of defects in high-K dielectric layers and embedded nanostructures are presented. In one example, the optical dispersion model includes a continuous Cody-Lorentz model having continuous first derivatives that is sensitive to a band gap of a layer of the unfinished, multi-layer semiconductor wafer. These models quickly and accurately represent experimental results in a physically meaningful manner. The model parameter values can be subsequently used to gain insight and control over a manufacturing process.

Claims19

Dependent claims

A method comprising:

illuminating a multi-layer structure disposed over a substrate with an amount of illumination light;
detecting an amount of collected light from the multi-layer structure in response to the amount of illumination light;
generating a spectral measurement of the multi-layer structure across a spectral range based at least in part on the amount of collected light;
determining a plurality of parameter values of an optical dispersion model of one or more layers of the multi-layer structure based at least in part on the spectral measurement, wherein the optical dispersion model includes a constrained Cody-Lorentz model having a rate of attenuation of an Urbach function defined such that a first derivative of a dielectric function with respect to energy is continuous at an Urbach transition energy of the constrained Cody-Lorentz model;
and
storing the plurality of parameter values of the optical dispersion model in a memory.

3 more elements

Dependencies are inferred from the claim text.

Dispersion model for band gap tracking

Life of this patent

Dispersion model for band gap tracking

Life of this patent

Abstract

Claims19