Advantage in using the combination of HL-800M and CAR process

摘要

The advanced 50 kV e-beam mask writing system HL-800M (Hitachi Co. Ltd.) was developed for 0.25 - 0.18 micrometer design-rule mask fabrication and widely applied. The combination of 50 kV e-beam writing system (EB) and Chemically Amplified Resist (CAR) is one of the solutions to improve accuracy for the fabrication of further high-end masks. The purpose of this study is to show the advantages of Critical Dimension (CD) accuracy in using the combination of 50 kV EB;HL-800M and positive-CAR; RE-5120P (Hitachi Chemical Co. Ltd.). In order to control CD, Proximity Effect Correction (PEC) is indispensable for the high acceleration voltage EB. Therefore, HL-800M has a high-speed-PEC system with hardware circuits. In this study, the PEC condition of HL-800M was optimized to improve CD accuracy. As a result, CD linearity of 18 nm was obtained in the pattern width from 0.7 micrometer to 3 micrometer. Besides, we evaluated the CD variation due to resist heating in using this combination. And, in the experiment of the resist heating effect, the CD variation was less than plus or minus 7 nm in the range of dosage ratio from 100% (11 $mu@C/cm$+2$/) to 500%. In other words, the CD variation due to resist heating is not so much serious problem for practical use in using the combination of the 50 kV EB and CAR.