36 0

Ellipsometric inspection of the inner surface of pellicle-covered masks

Title
Ellipsometric inspection of the inner surface of pellicle-covered masks
Author
안일신
Keywords
Ellipsometry; Haze; Lithography; Mask; Pellicle
Issue Date
2008-02
Publisher
The international Society for Optical engineering
Citation
Proceedings of SPIE - The International Society for Optical Engineering, v. 6922, Article no. 692227
Abstract
Crystal growth and haze formation on photomasks become serious problems in UV lithography. As the wavelength becomes shorter, photons carry more energy, so the chances of having a photochemical reaction become much higher. Pellicle, adhesive, residue from cleaning or resist strip process, and any contaminant in air can react with UV to form unwanted crystals and a haze layer on reticles. These will reduce the light transmission during exposure process. Thus, frequent mask inspection and periodic mask cleaning are needed to overcome these problems. However, these will in turn increase manufacturing cost and reduce mask life. Thus, a proper mask inspection tool is required to provide early warning of haze formation. In this work, we devised a new ellipsometric technique to investigate the inner surface of mask without removing pellicle. Ellipsometry is known to have mono-layer sensitivity and it can be used to measure any film or partial film formed on non-patterned spot in early stage of growth. However, when a pellicle covers the surface of mask, the ellipsometric data reflected from surface are extremely distorted due to the non-normal transmission through the pellicle. Thus, data analysis becomes extremely difficult without knowing the optical properties of pellicles. In order to solve this problem we developed compensation technique in which two blank pellicles are situated in the optical path in a way to compensate the polarization changes caused by the pellicle on mask. With this method, the conventional ellipsometry spectra of {Δ, Ψ} are deduced.
URI
https://www.spiedigitallibrary.org/conference-proceedings-of-spie/6922/1/Ellipsometric-inspection-of-the-inner-surface-of-pellicle-covered-masks/10.1117/12.772151.fullhttp://repository.hanyang.ac.kr/handle/20.500.11754/76752
ISSN
0277-786X
DOI
10.1117/12.772151
Appears in Collections:
COLLEGE OF SCIENCE AND CONVERGENCE TECHNOLOGY[E](과학기술융합대학) > PHOTONICS AND NANOELECTRONICS(나노광전자학과) > Articles
Files in This Item:
There are no files associated with this item.
Export
RIS (EndNote)
XLS (Excel)
XML


qrcode

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

BROWSE