Specific Process Knowledge/Lithography/Espacer

Espacer is a chemical that works as a discharging layer when e-beam writing on a non-conducting wafer; it is spun onto the wafer on top of the resist and easily rinsed off the wafer after e-beam exposure.

All substrates are grounded to the e-beam cassette when properly loaded. On a non-conducting substrate, the accumulation of charges in the substrates will however destroy the e-beam patterning. To avoid this, a charge dissipating layer is added on top of the e-beam resist; this will provide a conducting layer for the electrons to escape, while high-energy electrons will pass through the layer to expose the resist.

We have Espacer in stock and approved for use in the cleanroom. You can find a guideline for a process flow here: Process Flow CSAR + ESPACER.docx‎. Technical information of Espacer can be found here: Espacer_300_Technical_Info.pdf‎, Espacer_catalog.pdf‎.

Please contact Lithography if you wish to use this material.

Process	No ESPACER	ESPACER
Wafer	Borofloat 4" wafers (JB456), no pretreatment
Resist	AR-P 6200/2 AllResist E-beam resist
Spin Coat	1 min @ 4000 rpm, softbake 2 min @ 150 degC, thickness ~140nm
ESPACER		1 min @ 2000 rpm (no softbake), Manual Spinner 1 (Laurell)
E-beam exposure	2 nA, aperture 5, dose 150-310 muC/cm2, SHOT (A,10)
Rinse		Rinsed with hand shower in fumehood, dried with N2 gun
Developing	SX-AR 600-54/6 60 sec, 60 sec IPA rinse
Characterization	Nikon ECLIPSE optical microscope, E-5
All doses
230 muC/cm2
219 muC/cm2
Sputter Coated		<10nm Pt at DTU CEN
Characterization		Zeiss SEM supra 60VP, D-2
230 muC/cm2