OPERATION OF THE MACHINE
MA6 / MA8 - 1. Operation of the Machine - Rev.05 07-06
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the second alignment mark using the SCAN key
(315).
– substrate alignment
For an motorized stage only switch the manipula-
tor control to the stage activating the STG/TSA/
BSA button (601). Adjust the real substrate align
-
ment mark to the stored one only with the Θ-
movement of the alignment stage about 1/2 of the
misalignment. Switch the manipulator control to
BSA deactivating the STG/TSA/BSA button (601).
Press SCAN key (315) to toggle to the reference
position. Press GRAB IMAGE key (327) to release
the stored image. Deactivate the TOP/BOTTOM
key (326) and grab the new image using GRAB
IMAGE key (327). Repeat this substrate alignment
until there is no misalignment left.
– substrate to mask alignment
Move the substrate away using the x-y-movement
of the alignment stage to see a real mask align
-
ment mark. Focus on the mask plane by activat-
ing the TOP/BOTTOM key (326) and using the
corresponding TOP SUBSTRATE LEFT/RIGHT
focus regulator (215). Press GRAB IMAGE key
(327) to store the mask alignment mark. Move the
substrate back using the x-y-movement of the
alignment stage. Focus on the substrate plane by
deactivating the TOP/BOTTOM key (326) and us
-
ing the corresponding TOP SUBSTRATE LEFT/
RIGHT focus regulator (215). Align the substrate
alignment mark central symmetrical to the mask
alignment mark. Check the alignment using the
ALIGN CONT/EXP key (304).
5. Exposure
– EXPOSURE key
By pressing this key the substrate will move into
exposure position. Exposure takes place. Despite
the exposure was initiated hitting the UNLOAD
key before the light shutter has opened will con
-
tinue it's exposure without substrate exposure.
After finishing the wafer chuck moves down for
unload the exposed substrate.
6. Unload Mask
– CHANGE MASK key
Hit the CHANGE MASK key to start the unload
procedure. Follow the displayed instructions to
unload the mask.
1.4 Advanced Technology
1.4.1 Exposure Programs
An important parameter for the exposure is the con-
tact method between mask and wafer. The type of
exposure program is selectable with the SELECT
PROGRAM key. After this selection it is possible to
edit all corresponding parameters by pressing the
EDIT PARAMETER key.
Proximity Exposure
This is the most careful exposure for the mask. Mask
damage is reduced to a minimum. But the structural
resolution is not as high as with any contact expo
-
sure. Between mask and wafer is a distance left, the
exposure gap. The gap value is adjustable by the
EDIT PARAMETER key. The wedge error compensa
-
tion is performed by using three precision reference
spacers between mask and wafer.
Soft Contact Exposure
Mask and wafer are brought in contact. The structur-
al resolution is better than in proximity exposure. The
vacuum securing the wafer onto the chuck is main
-
tained during exposure. The only force to press the
wafer against the mask is the force applied during
WEC.
Hard Contact Exposure
This is similar to soft contact mode. After the wafer
has moved into contact the vacuum underneath the
wafer is switched off and nitrogen is purged under the
wafer instead. So a closer contact between wafer
and mask is guaranteed, even with large wafers.
Vacuum Contact Exposure
This mode performs the highest resolution levels. Af-
ter the WEC and alignment the wafer is brought into
contact with the mask. The rubber seal of a neces
-
sary vacuum chuck is creating a mini chamber be-
tween mask and wafer. The rubber seal pressure is
adjustable by the VACUUM SEAL regulator (206).
This chamber is evacuated in steps. Pre vacuum
gently pulls vacuum into that mini chamber to enable
a smooth contact between mask and wafer. Further
-
more it prevents gas bubbles to be trapped between
both. Full vacuum will be applied with the next step.
The wafer will be loaded in the closest contact posi
-
tion. The vacuum securing the wafer on the chuck is
replaced by nitrogen. In this mode the best contact
between mask and wafer is achieved. After the expo
-
sure nitrogen will purge into the mini chamber to
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