Angle-averaged calibration on a bare wafer measurement tool to improve ESFQR matching.

By using oppositely shaped calibration wafers to generate a tool-specific correction map, the method addresses systematic errors in ESFQR measurements, achieving a 40-70% reduction in errors and improving ESFQR matching accuracy in bare wafer measurement tools.

JP2026514625APending Publication Date: 2026-05-13KLA CORP
1 Cites 0 Cited by

Patent Information

Application Number
JP2025531381
Authority / Receiving Office
JP · JP
Patent Type
Applications
Current Assignee / Owner
Priority Date
2024-03-10
Filing Date
2024-04-04
Publication Date
2026-05-13

AI Technical Summary

Technical Problem

Current bare wafer measurement tools exhibit significant systematic errors in Edge Surface Flatness Quotient Range (ESFQR) measurements, leading to unreliable matching between tools and wafers, due to tool-specific and wafer-dependent errors such as cavity map inaccuracies, laser instability, and wafer retracing errors.

Method used

A system and method utilizing oppositely shaped calibration wafers to generate a tool correction map by measuring surface heights at multiple angles, creating non-flip and flip correction maps, and averaging these to produce a tool-specific systematic error correction map, which is applied to improve ESFQR matching.

Benefits of technology

The method significantly reduces systematic errors by 40-70%, enhancing ESFQR matching accuracy and improving tool performance by averaging out angle-dependent patterns, resulting in more reliable and precise ESFQR measurements.

✦ Generated by Eureka AI based on patent content.
Patent Text Reader

Abstract

The present invention relates to a method and system for generating tool correction maps. One method involves measuring the surface heights of the front and rear surfaces of first and second calibration wafers at multiple wafer rotation angles. The calibration wafers are low-profile wafers having opposite shapes to each other when viewed from the measuring device, and they may be a single wafer, but are inverted in the measuring device during the second measurement. The method also comprises generating a first correction map (uninverted) and a second correction map (inverted) at multiple rotation angles from the surface heights measured on the front and rear surfaces, respectively, of the first and second calibration wafers. Furthermore, the method includes the steps of generating a tool correction map by calculating the average of the uninverted and inverted correction maps, and storing the tool correction map for use in calibrating the thickness map of the wafer being tested.
Need to check novelty before this filing date? Find Prior Art