Image-based metrology software for analysis of features on masks and wafers

Abstract

Tebaldi 1 is a software tool developed at Intel Mask Operation (IMO) for quantitatively analyzing patterns in 2D. Its initial scope was to analyze aerial images taken with a microscope. However the software has recently been enhanced to support aerial images obtained through simulation, bitmap, jpeg and tiff files saved from the mask inspection systems and the scanning electron microscope (SEM). This article primarily focuses on the SEM module of the software. Tebaldi supports simulated aerial images generated through IMO's simulation based defect disposition system. This allows engineers to directly correlate 2D structures in an experimental aerial image, with those in a simulated image. To analyze SEM images, the software features scaling, alignment and calibration functions. Several linear and non-linear filtration techniques to reduce noise and charging exist. Custom convolution kernels can be user defined. Ability to segment features and extract contours also exist. Further, these contours can be overlayed and shortest distances between corresponding points can be computed in a user friendly manner with a high degree of confidence. Tebaldi is currently used in production to disposition defects in repaired sites on masks shipped from IMO as well as to compare SEM images to determine the pattern fidelity across mask writers and processes within IMO.

Applications of large field of view e-beam metrology to contour-based optical proximity correction modeling

“…Optical proximity correction (OPC) model calibration methods with image contours extracted directly from top-down scanning electron microscope (SEM) images have been broadly investigated in the past decade. In the early years, Intel developed an in-house image contour extraction simulation system for mask defects analysis 1 . In the same year, the concept of OPC modeling based on the extracted image contours of an after-development inspection (ADI) SEM image was also introduced 2 .…”

“…In the early years, Intel developed an in-house image contour extraction simulation system for mask defects analysis. 1 In the same year, the concept of OPC modeling based on the extracted image contours of an after-development inspection (ADI) SEM image was also introduced. 2 The engineering solutions that utilize automatically extracted two-dimensional (2D) image contours from ADI as well as after-etch inspection are challenging.…”