OCD study of critical dimension and line-shape control of shallow-trench-isolation structures

Ye Feng; Xiaodong Zhang; Beverly Cheung; Zhuan Liu; Mita Isao; Manabu Hayashi

doi:10.1117/12.536582

24 May 2004 OCD study of critical dimension and line-shape control of shallow-trench-isolation structures

Ye Feng, Xiaodong Zhang, Beverly Cheung, Zhuan Liu, Mita Isao, Manabu Hayashi

Proceedings Volume 5375, Metrology, Inspection, and Process Control for Microlithography XVIII; (2004) https://doi.org/10.1117/12.536582
Event: Microlithography 2004, 2004, Santa Clara, California, United States

Abstract

Shallow-Trench-Isolation (STI), as one of the primary techniques for device isolation in complementary metal-oxide semiconductor (CMOS), requires accurate and precise CD and line-shape control during wafer process. Thus, the measurement of the critical dimensions after lithography and after formation of the STI structure is extremely important for process control. Currently used SEM technologies are either destructive or incapable of identifying the profile features. The necessary averaging of CD-SEM measurements to compensate for its large error diminishes its usage in automatic process control. In this paper we use the Optical Critical Dimension (OCD) technique to study focus exposure matrix (FEM) wafers of photoresist patterns and STI structures and compare the results with CD-SEM measurements. OCD measurement is performed with normal-incidence polarized reflectometry. Rigorous Coupled-Wave Analysis (RCWA) is combined with real-time regression to provide CD and profile parameters with excellent sensitivity to sub-50 nm grating lines. Thus, non-destructive and fast real-time measurements are easily accomplished during wafer processing. Optimization of STI model parameters is discussed. The critical dimensions of 121 dies extracted by OCD exhibit excellent correlation with those obtained by CD-SEM, with R-squared as high as 0.995 on STI wafers.

Citation Download Citation

Ye Feng, Xiaodong Zhang, Beverly Cheung, Zhuan Liu, Mita Isao, and Manabu Hayashi "OCD study of critical dimension and line-shape control of shallow-trench-isolation structures", Proc. SPIE 5375, Metrology, Inspection, and Process Control for Microlithography XVIII, (24 May 2004); https://doi.org/10.1117/12.536582

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available