Methods and system for lithography process window simulation

US8200468B2 · kind B2 · utility

Assignee

• ASML NETHERLANDS B.V. · NL

Inventors

• Jun Ye · Palo Alto, US
• Yu Cao · Saratoga, US
• Hanying Feng · Fremont, US

Key dates

• Filing date: Dec 5, 2008
• Grant date: Jun 12, 2012
• Expiry date: Jan 7, 2031

Classification

• Technology area (CPC G): Physics
• CPC primary: G03F7/70991
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A method of efficient simulating imaging performance of a lithographic process utilized to image a target design having a plurality of features. The method includes the steps of determining a function for generating a simulated image, where the function accounts for process variations associated with the lithographic process; and generating the simulated image utilizing the function, where the simulated image represents the imaging result of the target design for the lithographic process. In one given embodiment, the function for simulating the aerial images with focus and dose (exposure) variation is defined as:I(x,f,1+ε)=I0(x)+└ε·I0(x)+(1+ε)·a(x)·(f−f0)+(1+ε)·b(x)·(f−f0)2┘where IO represents image intensity at nominal focus and exposure, fO represents nominal focus, f and ε represent an actual focus-exposure level at which the simulated image is calculated, and parameters “a” and “b” represent first order and second order derivative images with respect to focus change.