Development of a Mask-Scan EB Mask Writing System

Transcription

1 Development of a Mask-Scan EB Mask Writing System Munehiro OGASAWARA, Shinsuke NISHIMURA, Kiminobu AKENO, Soichiro. MITSUI, Mitsuko SHIMIZU, Hideo KUSAKABE, and Toru TOJO EUV Process Technology Research Laboratory, ASET Corporate R&D Center, Toshiba Corp., 1, Komukai Toshiba-cho, Saiwai-ku, Kawasaki , Japantel : , fax :

2 Electron source Condenser lens Shaping aperture Projection lens Scan deflector DAC amp Electron beam optics Data processing circuit Mask-stage EB-mask Sub-deflector Main deflector Objective lens Deflection control circuit Substrate (mask) Computer Mask handling system

3 EB-mask patterns and beam scanning method Rectangular beam (S1 aperture image) 300 µm (on EB-mask) 1st scan 2nd scan Mask pattern VSB aperture

4 Shot number reduction in mask-scan strategy 6 4=24 shots (VSB: =780 shots) 10 10=100 shots (VSB: = shots) 20 µm (on substrate)

5 Appearance of EB-mask scan type writing system (α/2) Electron optical column Scan deflection amplifier In situ particle inspection system (MUSE) Reticle auto-loader

6 Electron optical column Scan deflection amplifier EB-mask XY -stage EB-mask loader

7 Design Specification Acceleration voltage 50 kv Current density 20A/cm 2 Beam aberration 30 nm Main field 1 mm Sub-field 64 m Maximum Pattern size 20 m

8 EB-mask XY -stage Y-driver EB-mask X-driver -driver Laser interferometer Laser mirror XY -driver: Ultrasonic linear motor

9 EB-mask pattern for evaluation Top-view with optical microscope 3.2 µm µm Isolation Oblique parallel lines

10 Projected patterns 1µm resist : ZEP7000, 400nm thick

11 Environment-proof Writing chamber Alignment chamber (Pre-alignment) Electron cokumn I/O-arm (Transport of CFP between I/Ochamber and RMS) SMIF Pod RMS CFP Robot chamber (Vacuum robot for mask handling installed) I/O-chamber (Vacuum load-lock)

12 Room temperature ±0.1 C Δt Constant temperature water ±0.01 C Mask temperature RMS I/O-arm I/O-ch (vacuum load-lock) Development of this area Pump P AL-ch (mask soaking) ΔT

13 Optimization of I/O-ch evacuation time - Measurement of mask temperature change - Mask surface temperature C I/O-arm RMS Pump P I/O-ch (vacuum load-lock) ΔT Time sec AL-ch (mask soaking) Pressure in AL-ch MPa Temp.for M Temp. for L Temp. for H M; Middle evacuation speed L; Low evacuation speed H; High evacuation speed

14 Development of temperature stabilized AL-ch - Simulation on mask temperature soaking time - I/O-arm RMS Pump P I/O-ch (vacuum load-lock) AL-ch (mask soaking) Temperature C hr 0.04 C Mask temp. AL-ch temp. Constant temp. plate Soaking time sec

15 Development of temperature stabilized AL-ch - Simulation of robust performance on AL-ch temp. change - AL-ch Mask Constant temp. plate RMS I/O-arm I/O-ch (vacuum load-lock) Analysis model Temperature C Pump P AL-ch (mask soaking) AL-ch temp. Constant temp. plate Mask temp C Time sec

16 Development of environment-proof writing chamber Thermal expansion reduction of writing chamber - I/O-arm RMS Pump P I/O-ch (vacuum load-lock) 0.0 Position change (µm) AL-ch (mask soaking) ~ nm/deg This work ~ nm/deg writing-ch ~1/ Temperature(deg.)

17 Development of thermally stabilized XY stage Low heat generation bearing and active thermal control system - Mask Writing chamber Heater Cooling plate RMS X-Y stage Constant temperature water I/O-arm Pump P Stage controlling system Thermal stabilization feedback control Measurement of the top plate temperature Heater control Plate temperature, C Control of the order of C is realized writing-ch Stop X move Stop Y move Thermal control plate Time, min Top plate X-stage Stage temperature, C

18 Summary! To realize the required throughput in writing the super leading edge masks, EB mask scan strategy has been proposed, and proved its principle.! Precise mask temperature control technology and environment-proof technology has been developed for improve the pattern positioning accuracy.! Prototype system of the Mask-Scan Type EB Mask Writer has been developed and is being evaluated for EUVL mask writing in ASET EUVL program.! Mechanical and thermal phenomena occurring on the EUVL mask is being studied.

19 Acknowledgement A part of this work was performed under the management of ASET in the METI R&D program supported by NEDO.