Equipment Overview

Electron beam lithography (EBL) has long been established as the premier technique for defining structures at the nanoscale.These include:

  • The ability to reproducibly achieve feature sizes below 100 nm
  • Multilayer lithography with less than 80 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: Φ150, 200 mm.
  • Standard photomask holders are available for the mask sizes: 5”, 6”.

LEICA WEPRINT 200 E-Beam stepper

Introduction

The leica werpint 200 direct writing toolshave been introduced to meet the pattern generation task. It features shaped beam /vector-scan deflection / moving stage while exposure technology which is the strategy of choice for high resolution CD-related accuracies without throughput compromise. With an effect address grid of 20nm and a minimum feature size of isoline100nm it possesses the key attributes for advanced direct write applications without the throughput bottleneck associated with raster system. These outstanding features are provided within a truly production system of compact design which includes external robotic handing and wafer loading.

Pattern 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.

- Rectangles with 45degree rotated edges.

- Isosceles right triangles in four possible positions.

- All of them can be changed in size with steps of 20 nm.

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

Dosagerang: 0.1-1000μC/cm2.

Electronoptics:

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

Beam energy: 40KeV.

Blanking: electrostatic beam blanking

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.

Workstage / work chamber

Stage travel : 201 nm x 201 nm

Drive mechanism : electronics-motor with recirculating friction

Screw in each coordinate.

Position measurement: laser interferometer system of 5 nm.

Substrate holder:The wafer holders are equipped with an electrostatic chuck module to achieve high wafer flatness during exposure.

Chamber / substrate temperature control: via chiller, thermostatting stability 0.02 k.

Substrate handling system

External 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. Two substrate holders (1pair) are exiting for each substrate size. The outer-handling cycle rubs parallel to the exposure processes.

Inner handling: 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. Substrate holder and inserted substrate can now be adapted to the required temperature. The internal shuttle mechanism works as a double-claw manipulator.