EPFL Swiss Institute of Technology Lausanne Page 2
CMi Center of MicroNanoTechnology
3.Preparation: Mask Loading
•Unclamp the mask holder with the 2 screws on
the right side of the frame.
•Take the mask holder out of the frame, rotate it
and put it on the small table left side of the
MJB4.
•Fit properly the mask on the mask holder by
contacting the three metal pins.
•On the MJB4 touchscreen, go in the “Main
Menu” section. Press «Mask vacuum is off» to
turn on vacuum clamping. Verify that the mask
does not move.
•Put the mask holder with the mask back into
the MJB4. Clamp the mask holder with the 2
screws. Make sure it is sufficiently fixed.
4.Preparation: Exposure Recipe
•Calculate your optimal exposure time,
according to the recommended exposure dose
given on the CMi website and the lamp
intensity. Default illumination setup on MJB4:
Intensity = 20mW/cm2, i-line (365nm)
illumination.
•On the MJB4 touchscreen, press “Parameters”
to access the exposure settings.
•Select the exposure mode under number 1):
“Align + Exp.” = standard mode.
“Flood Exp.” = no mask, full wafer
exposure.
“Test Exp.” = to expose the wafers
several (defined by the “exposure cycles”
parameter) times with different exposure
times.
•Select the contact mode under number 2):
“Hard Contact” = standard mode.
“Soft Contact” = for fragile wafers or
extremely thick resist.
“Vacuum Contact” = NOT AVAILABLE on
MJB4.
*Gap Exposure” = to expose with a gap
between wafer and mask (proximity).
•Set-up the rest of the parameters
Hard Contact time: 10s
Exposure time: “x” (calculated before)
Exposure cycles: 1
•To perform split-exposure, change the
“Exposure cycles” parameter to any values
higher than 1. “Wait time” parameter will show
up below.
•Once the recipe parameters are set, press the
“Load” key to save your parameters.
•Make sure that the CIC mode is set to constant
power (CP). The use of other exposure modes
is not recommended with the MJB4 mask-
aligner.
5.Preparation: WEC settings
On the MJB4, the wedge error compensation
(WEC) procedure for fine tuning of mask/wafer
contact position and parallelism is done manually.
Follow this procedure:
•Before starting check that WEC pressure
setting is higher than 0.05 MPa!If it is lower
please adjust with the appropriate knob (front
panel, right of the machine).