Electron beam patterning
A pattern would be designed and drawn with the support of Elphy Quantum
software (Design CAD by GDSII d – Calma Stream). Exposure pattern
was done by LEO 1430 SEM.
Figure 4.5: Pattern design for CNTs
Initially, samples were loaded to LEO-chamber with the acceleration
voltage of 30 kV, beam current 40 A. The wanted position for exposing,
dose, current, spot-size e, etc will be adjusted on the monitor before exposure
samples. When the exposure process takes place, the electron beam
breaks the polymer into fragments and modifies the resist, the resist sensitivity
is 200 C/cm2.
The pattern was exposed twice: rough exposure is used for large details.
working are is 265 m , current is 50 pA; fine exposure is used for
the tiny details with 64 m of working area, current is 20 pA.
dGDSII is a computer program to store and record data in byte unit [12]
eA spot-size is the electron beam diameter. The smaller the
spot-size the more tiny structures of the sample will be created
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CHAPTER 4. EXPERIMENTAL APPROACHES
Figure 4.6: The area of each
square is around 8×8 m
Figure 4.7: Ma