title: Carbon contamination analysis and its effect on extreme ultra violet mask imaging performance using coherent scattering microscopy/in-situ accelerated contamination system.
abstract: The coherent scattering microscopy/in-situ accelerated contamination system (CSM/ICS) is a developmental metrology tool designed to analyze the impact of carbon contamination on the imaging performance. It was installed at 11B EUVL beam-line of the Pohang Accelerator Laboratory (PAL). Monochromatized 13.5 nm wavelength beam with Mo/Si multilayer mirrors and zirconium filters was used. The CSM/ICS is composed of the CSM for measuring imaging properties and the ICS for implementing acceleration of carbon contamination. The CSM has been proposed as an actinic inspection technique that records the coherent diffraction pattern from the EUV mask and reconstructs its aerial image using a phase retrieval algorithm. To improve the CSM measurement accuracy, optical and electrical noises of main chamber were minimized. The background noise level measured by CCD camera was approximately 8.5 counts (3 sigma) when the EUV beam was off. Actinic CD measurement repeatability was <1 A (3 sigma) at 17.5 nm line and space pattern. The influence of carbon contamination on the imaging properties can be analyzed by transferring EUV mask to CSM imaging center position after executing carbon contamination without a fine alignment system. We also installed photodiode and ellipsometry for in-situ reflectivity and thickness measurement. This paper describes optical design and system performance observed during the first phase of integration, including CSM imaging performance and carbon contamination analysis results.
authors: Department of Materials Science and Engineering, Hanyang University, Seoul 133-791, Korea.
authors: Chang Young
authors: CY
authors: Jeong
authors: Sangsul
authors: S
authors: Lee
authors: Jong Gul
authors: JG
authors: Doh
authors: Jae Uk
authors: JU
authors: Lee
authors: Han-sun
authors: HS
authors: Cha
authors: William T
authors: WT
authors: Nichols
authors: Dong Gun
authors: DG
authors: Lee
authors: Seong Sue
authors: SS
authors: Kim
authors: Han Ku
authors: HK
authors: Cho
authors: Seung-yu
authors: SY
authors: Rah
authors: Jinho
authors: J
authors: Ahn