Novel Technique for Phase-Shifting-Mask Repair Using Focused-Ion-Beam Etch-Back Process

• Published in: Japanese Journal of Applied Physics Vol. 31; no. 12S; p. 4468
• Main Authors: Hosono, Kunihiro, Nagamura, Yoshikazu, Kusunose, Haruhiko, Yoshioka, Nobuyuki, Yaichiro Watakabe, Yaichiro Watakabe, Yoichi Akasaka, Yoichi Akasaka
• Format: Journal Article
• Language: English
• Published: 01.12.1992
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.31.4468

For the repair of phase-shifter (PS) defects with good topology and without optical deterioration, a new repair technique has been developed by using focused-ion-beam (FIB) etch-back and laser-explosion processes. This technique mainly consists of three steps: (1) leveling of defects by FIB-assisted chemical vapor deposition (CVD) or filling with spin-coated SOG film, (2) etch-back or/and exposure by Ga-FIB scanning with the detection of total secondary ions which inform the end point of etch-back, and (3) elimination of Ga-implanted shifter (or quartz) layer by a Nd:YAG laser shot. The excess shifter (bump defect) was rubbed out by adjusting the milling rate of the FIB-CVD film and its confined defects. For the missing shifter (divot defect), the filling SOG was screened off within the defect by use of Ga-FIB milling (exposure) and development. The Ga-implanted layer was eliminated by the laser explosion and so the repaired area was recovered in transmittance from less than 50% up to 98%.