Introduction

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15 Νοε 2013 (πριν από 3 χρόνια και 10 μήνες)

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Equipment
Overview

Electron beam lithography (EBL) has long been established as the premier technique
for defining structures at the n
anoscale
.

These include:




The ability to reproducibly achieve feature sizes below
100

nm




Multilayer lithography with less

than
40

nm

overlay




Mix and match EBL and photolithographic

I
-
line stepper
processing




Nanoimprint template fabrication




Patterning on thin silicon and silicon nitride membranes




Standard
wafer holders are available for the wafer sizes:
Φ
150, 200
mm.



Standard
photomask holders are available for the mask sizes: 5
”, 6”
.

LEICA WEPRINT 200 E
-
Beam stepper

Introduction

T
he leica werpint 200 direct writing
tools

have

been introduced to meet the pattern
generation task.
I
t features shaped beam /v
ector
-
scan deflection / moving stage while
exposure technology which is the strategy of choice for high resolution CD
-
related
accuracies without
throughput

compromise.
W
ith an effect address grid of 20nm and a
minimum feature size of isoline100nm it posses
ses the key attributes for advanced
direct write applications without the throughput bottleneck associated
with

raster
system.
T
hese outstanding features are provided within a truly production system of
compact design which includes external robotic handin
g and wafer loading.

P
attern generation system:



beam shaping: multiple beam
-
shaping
diaphragms

create

variable
-
shaped


beam


which is able to expose at target level:


-

Rectangles

with axial
-
parallel edges.


-

Recta
ngles

with 45degree rotated edges.


-

Isosceles

right triangles in four possible positions.


-

A
ll of them can be changed in size with steps of 20 nm.



Writing

methodology: write
-
on the
-
fly process: the work stage moves
c
ontinuously line by line at the same time as beam positioning and exposure
take place.



Dosage

rang:

0.1
-
1000
μ
C/cm2.



Electron

optics:



Electron

source: LaB6 directly heated, gun with
integrated ion
-
pump.



Beam

energy: 40KeV.



Blanking
: electrostatic beam blan
king



Electron

lenses: 3 condensers, 1demagnification lens 1 objective lens, 1
lens for fast focus correction, 1 correction lens for
beam shaping
.



Beam current stability: within 1


over eight hours.

W
orkstage / work chamber



S
tage travel : 201 nm x 201 nm



D
rive mechanism : electronics
-
motor with recirculating friction

S
crew in each coordinate.



P
osition
measurement:

laser interferometer system of 5 nm.



S
ubstrate
holder:

The wafer holders are

equipped with an electrostatic
chuck module to achieve high wafer fl
atness during exposure.



C
hamber / substrate temperature
control:

via chiller, thermostatting stability
0.02 k.

S
ubstrate handling system



E
xternal
handling: The

loading of the substrate is
affected

via SMIF
-
pods
with the help of cassettes.
A

dust class 1 is

achieved at the place of the
substrate by using a special enclosure.
Substrate

can be change fully
automatically.
T
wo substrate holders
(1pair)

are exiting for each substrate
size.
T
he outer
-
handling cycle rubs parallel to the exposure processes.



I
nner
ha
ndling:

after a substrate has been put on a substrate holder inside
the airlock the outer airlock gate is closed and airlock volume will be
evacuated.
S
ubstrate holder and inserted substrate can now be adapted to
the required temperature.
T
he internal shut
tle mechanism works as a
double
-
claw manipulator.