15 March 2007 Alignment method of low-energy electron-beam direct writing system EBIS using voltage contrast image
Author Affiliations +
Abstract
We have developed the EBIS (Electron Beam Integrated System), which is a character projection (CP) type low-energy electron-beam direct writing (LEBDW) system. In this system, the proximity effect due to backscattering electrons is very small under the condition that the energy of primary electron is 5 keV. However, there is a serious problem, in that the signal of the mark buried under a thick insulator couldn't be detected. To overcome this problem, we adopted a mark detection method using Voltage Contrast (VC) image with negative charge on the sample surface. So far, we have detected the signal of alignment mark buried under 600nm-thick (nmt) tri-layer resist using VC image on EBIS. Then we exposed overlay patterns with alignment using the mark detection with VC image. The mark image is very clear with a sufficiently high contrast. The asymmetry originating from VC is mitigated by means of FB scanning. Using this VC mark detection method, EB drawing was performed with alignment with 600nmt tri-layer resist on Si substrate. Moreover, VC mark detection with 600nmt tri-layer resist on the substrates of back-end-of-line (BEOL) of logic device was performed and the mark images with sufficient contrast were obtained. Although the characteristic distortion of VC image exists, mark detection is possible by using X/Y separate scanning, which consists of X-direction scanning to get an X position and Y-direction scanning to get a Y position in non-charged area.
© (2007) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Takeshi Koshiba, Takeshi Koshiba, Takumi Ota, Takumi Ota, Tetsuro Nakasugi, Tetsuro Nakasugi, Fumihiko Nakamura, Fumihiko Nakamura, Katsuhide Watanabe, Katsuhide Watanabe, Kazuyoshi Sugihara, Kazuyoshi Sugihara, } "Alignment method of low-energy electron-beam direct writing system EBIS using voltage contrast image", Proc. SPIE 6517, Emerging Lithographic Technologies XI, 651713 (15 March 2007); doi: 10.1117/12.711368; https://doi.org/10.1117/12.711368
PROCEEDINGS
12 PAGES


SHARE
Back to Top