Cleanroom Lithography

Description

Lithography Processes

Optical and e-beam lithography processes with both positive and negative-tone resists are available for substrates from 200-mm-diameter wafers down to samples below 10mm in size and square mask plates up to 9 inches.

Direct-write lithography with a 405nm laser writer for processing samples from 10mm in size to wafers up to 200mm and mask plates up to 9 inches, as well as exposure on flexible substrates.

With positive tone photoresists (AZ series)
- Standard process thickness 600nm, 1000nm, 1200nm, 2200nm for wet and dry etch processes
- Limited capabilities with 200nm for highest resolution
- Limited capabilities with 4µm to 20µm
- Standard process with underlying LOR layer for lift-off process
- Process with negative profile with 600nm photoresist (for lift-off of metal deposition)
- Bilayer resist with lift-off resist
- Grey-level lithography (60 levels available) for 2.5D fabricated structures
With positive tone photoresist series for greyscale lithography (ma-P 1200 series)
- Film thickness up to 60µm
- Grey-level lithography (128 levels available)
With negative tone phororesists (mr series):
- Pocesses with 1 to 40µm epoxy resin for direct-write for specific applications (microelectronics passivation, epoxy micromachines, microfluidics)

INL cleanroom is equipped two Mask Aligners dedicated for production. One uses a mercury lamp and 7-inch masks, using different UV bands with top and bottom alignment. The other uses 9-inch masks and an LED source; can perform automated alignments for an increased throughput and precision in aligned exposure from both top and bottom sides.

With positive tone photoresists (AZ series)
- Standard process thickness 600nm, 1000nm, 1200nm, 2200nm for wet and dry etch processes
- Standard process with underlying LOR layer for lift-off process
With special resists
- UV-sensitive polyimide (e.g., for flexible devices)
- Photo sensitive ProTEK PSB (negative-working etch mask for KOH wet etch for silicon micromachining)
- UV-sensitive SU-8 (negative tone photoresist up to 150µm thickness)

Nanoimprint lithography is a recent addition to the capabilities of INL, enabling the patterning of a wide range of hard and soft materials and the fast fabrication of 3D micro- and nanostructures in a single step. The masters to be used for imprint can be produced using our DWL or EBL tools.

INL is equipped with e-beam lithography which has demonstrated resolution down to 7nm.

A range of photoresist options has been validated

Positive tone PMMA 100 nm to 430 nm and bilayer PMMA processes for lift-off of nanostructures
Positive photoresists ZEP520 and AR-P 6200 for etching applications
Negative tone AR-N 7520 for etching of nanopillars, range 80nm to 800nm in thickness, achieving typically 50nm lateral size for 200nm photoresist thickness.
Limited testing on HSQ negative tone resist for highest resolution and semiconductor applications
Epocor/Epoclad epoxy resist for direct write of optical waveguides

The e-beam system accepts wafers of 3 inch and 200mm in diameter, sample parts of irregular shapes fitting into a 76mm circular holder, and glass masks 6 inch in diameter. The e-beam exposure files are converted using Genisys Layout Beamer and can include proximity effect correction in dose factor and in shape.

Specifications

Suss Microtec

High-throughput Coating & Development Process

Handling of round and square substrates up to 200mm.
Thin, thick resists, polyimide.
Precision edge bead removal.
Process up to 25 wafers in one batch.

Suss Microtec

Optical Exposure with Mask Aligner

Substrates up to 200mm
Masks from 2″ to 9″ plates
Broadband wavelength: 365/405nm
Modes of operation: Soft, Hard and Vacuum Contact, Proximity exposure and Flood exposure
Automatic alignment and backside-alignment capability

Heidelberg

Exposure with Direct Write Laser

Substrates up to 200mm
Minimum structure size: 700 nm
Autofocus: optically or pneumatically
Auto-measurement capability
Grey-level lithography with 128 levels

Obducat Eitre 8

Nanoimprint lithography system

Allows both thermal and UV nanoimprint lithography
Full area: 8″ square

Vistec E-beam Lithography

Thermal Field Emission gun for operation at 50 and 100kV and up to 100nA beam current
Capability of writing on Si and other substrates (glass, metals, SiO₂,) up to 200mm size
Capability of writing 150-mm optical masks for contact and projection lithography
Write field up to 520µm.

Ascent+ facility
INL

Platform Technologies