Micro-profile measurement of a transparent coating using windowed Fourier transform in white-light vertical scanning interferometry

Suodong Ma; Chenggen Quan; Rihong Zhu; Lei Chen

doi:10.1117/12.970532

15 October 2012 Micro-profile measurement of a transparent coating using windowed Fourier transform in white-light vertical scanning interferometry

Suodong Ma, Chenggen Quan, Rihong Zhu, Lei Chen

Author Affiliations +

Proceedings Volume 8417, 6th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment; 841725 (2012) https://doi.org/10.1117/12.970532
Event: 6th International Symposium on Advanced Optical Manufacturing and Testing Technologies (AOMATT 2012), 2012, Xiamen, China

Abstract

Owing to free of the phase ambiguity problem, white-light vertical scanning interferometry (WLVSI) is commonly used to inspect surface profiles of objects, especially for the micro-profile measurement of microelectromechanical systems (MEMS) devices. Although numerous algorithms have been proposed for the white-light interference signal analysis, most of them focused only on test objects with a single reflective surface. In this paper, a technique to measure the micro-profile of a transparent coating using windowed Fourier transform in WLVSI is described. A windowed Fourier filtering (WFF) operation is first adopted to roughly estimate the local peak positions of a recorded interference signal. Subsequently a least-square estimation based on the retrieved phase values of a filtered signal is separately applied into previously extracted local peak positions to achieve more accurate micro-profile results. The thickness of the coating can be finally estimated by the retrieved reflective surfaces. Experimental works, conducted on a flat plate and a MEMS device with a transparent coating on its substrate, demonstrate the validity of the proposed method.

Citation Download Citation

Suodong Ma, Chenggen Quan, Rihong Zhu, and Lei Chen "Micro-profile measurement of a transparent coating using windowed Fourier transform in white-light vertical scanning interferometry", Proc. SPIE 8417, 6th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, 841725 (15 October 2012); https://doi.org/10.1117/12.970532

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