Lithography

Within the cleanroom is a 40 m²lithography area, illuminated with yellow light to enable the use of photoresist. Positive and negative photoresists are used in the laboratory, which is also equipped for bi-level resist processes.

Coating

In the School of Engineering

Laurell WS-650Mz-23 spin coater. Used for applying photoresist to samples from the liquid phase.
- Accepts wafers up to 150mm (6") and small samples down to <1cm².
- Cleanliness: excellent. Dedicated to conventional photoresists.
- Standard primer: hexamethyldisilazane (HMDS).
- Standard photoresists:
  - Positive: S1818
  - Image reversal: AZ5214e
  - Negative: AZ nLOF 2035
  - Other photoresists available on request.
- Standard dielectrics: polyimide.
- Dedicated spin-coater for clean processes & high-resolution lithography.
- Example applications: power MOSFET gate, source & JTE patterns, electrode patterns, encapsulant dielectric.
Laurell WS-650Mz-23 spin coater. Allows coating from the liquid phase for materials such as SU-8 photoresist and polyimide.
- Accepts wafers up to 150mm (6") and small samples down to <1cm².
- Cleanliness: good. Supports materials with modest solvent soluability, such as SU-8 photoresist.
- Standard primer: hexamethyldisilazane (HMDS).
- Standard photoresists: SU-8. Other photoresists available on request.
- Flexible spin coater, supporting materials with poor compatibility with high-resolution photolithography.
- Example applications: microfluidic structures.

In the Department of Physics

Laurell WS-650Mz-8NPPB spin coater. Used for applying photoresist to samples from the liquid phase.
- Accepts wafers up to 150mm (6") and small samples down to <1cm².
- Cleanliness: good.
- Standard primer: hexamethyldisilazane (HMDS).
- Standard photoresists: ???
- Example applications: electrode patterns.

Exposure

In the School of Engineering

SUSS MicroTec MA8/BA8 mask aligner. Semi-automated workhorse tool for mask alignment and UV exposure.
- Accepts wafers up to 200mm (8") and small samples down to <1cm².
- Cleanliness: excellent. Dedicated to conventional photoresists.
- Minimum resolution: 0.75µm approx.
- Extended capability: back-side alignment, auto-alignment.
- Core mask aligner tool. User-friendly, high throughput, high flexibility for both large and small samples.
- Example applications: power MOSFET gate, source & JTE patterns, electrode patterns.
SUSS MicroTec MJB3 manual mask aligner. Manual mask aligner for non-standard processes.
- Accepts wafers up to 75mm (3") and small samples down to <1cm².
- Cleanliness: good. Highly flexible platform.
- Minimum resolution: 1.5µm approx.
- Flexible mask aligner, supporting materials with poor compatibility with high-resolution photolithography.
- Example applications: microfluidic structures.
SUSS MicroTec MJB4 manual mask aligner. Manual mask aligner to support other tools
- Accepts wafers up to 75mm (3") and small samples down to <1cm².
- Cleanliness: excellent.
- Minimum resolution: 0.75µm approx.
- Offers better flexibility than MA8 and improved useability from MJB3.
SUSS MicroTec MA8/BA8 substrate conformal imprint (SCIL, also known as nano-imprint) function. Pattern transfer from stamp to resist to achieve nano-scale features with high throughput.
- Accepts wafers up to 75mm (3").
- Cleanliness: excellent.
- Minimum resolution: 50nm approx.
- Patterning technology for nano-scale features without e-beam lithography. Capable of large-area patterning with rapid turnaround.
- Example applications: nano-antenna structures.

In the Department of Physics

Heidelberg Instruments μPG 101 laser writer. Direct write of pattern into conventional photoresist using UV laser.
- Accepts wafers up to 150mm (6") and small samples down to <1cm².
- Cleanliness: good.
- Minimum resolution: 0.6µm approx.
- Direct write of pattern files to sample, eliminating lead time and cost for photomasks.
- Example applications: electrode patterns, photomask fabrication.

Develop

In the School of Engineering

Manual glassware development for small and irregular substrates.
Laurell EDC-650Hz spin developer for 2-3" diameter substrates.

In the Department of Physics

Coating

Spin 150 manual resist spin coater. Supports 0.5cm square to 6" diameter substrates.
Laurell WS-650Mz auto dispense spin coaster. Supports 2-6" diameter substrates.

Exposure

Suss Microtec MJB3 manual mask aligner. Supports 0.5cm square to 3" diameter substrates with a 1.5 µm resolution
Suss Microtec MA/BA8 mask aligner with SCIL (surface conformal imprint lithography) adaptation. Supports 1cm square to 8" diameter substrates with a 0.75 µm resolution.
SCIL processing on 2" and 3" diameter substrates to define features down to 50nm.

Develop

Manual glassware development for small and irregular substrates.
Laurell EDC-650Hz spin developer for 2-3" diameter substrates.

Monmouth Scientific Circulaire T1400 filtration fume cupboard with carbon filter(Processing materials for lithographyonly)
x2 hotplates
Laurell spincoater WS-650Mz-8NPPB
Ultrasonic bath
High purity N2 gas
DI water

Permitted substances:

1)Photoresists

2)Photoresists’ primers

3)Photoresists’ developers

4)Photoresists’ strippers

5)Acetone

6)Ethanol

7)IPA

8)DI water

Lithography Fume Cupboard

Primers, photoresists, developers and removers:

AZ ECI 3007 positive photoresistLink opens in a new windowLink opens in a new windowLink opens in a new window
AZ 5214 E image reversal photoresistLink opens in a new windowLink opens in a new windowLink opens in a new window
S1813 positive photoresist
Protek and primer
Hexamethyldisilazane (HMDS) primer
AZ 326 MIF developer (TMAH based) X2
Technistrip (lift-off)

A new user training: Mike Crosby and Alan Burton

Technical support: Mike Crosby and Alan Burton

Risk assessment

Risk Assessment for Returning to Work during the Covid-19 Lockdown Easing PeriodLink opens in a new windowLink opens in a new windowLink opens in a new window

All usersof any fume cupboard are required to complete the moodle training course (https://moodle.warwick.ac.uk/course/view.php?id=38253) and their competency recorded on an approved user list.

Heidelberg Instruments μPG 101is an extremely economical and easy to use micro pattern generator for direct writing applications and low volume mask making. The system can be used for applications such as MEMS, Bio MEMS, Integrated Optics, Micro Fluidics or any other application that requires high precision, high-resolution microstructures.

The tabletop system features exchangeable write modes to meet the resolution and write speed requirements of specific application. It is a lithography system, which can produce sub-micron features. The small address grid allows placement of structures with very high accuracy. The real-time autofocus system monitors and corrects focus position during exposure, which guarantees high resolution and repeatability over the entire exposure area. Small address grid and real-time autofocus system are essential features for a professional micro pattern solution.

Applications for the µPG 101 include Semiconductors, Life Science, MEMS, Sensors, Actuators, Material Research, and any other application that requires microstructures.

Key features

Write speed up to 90 mm²/ min
Substrates up to 150 mm x 150 mm
Structures down to 0.6 µm
UV (375 nm, 70 mW) diode laser source
Write Mode Mix and Match
Optical Autofocus

Multiple data input formats
Basic gray scale exposure mode
Camera system for alignment
Multiple exchangeable write modes
Vector and raster exposure mode

Specification

WRITE MODE	I	II	III	IV
Minimum Structure Size [μm]	0.6	1	2.5	5
Maximum write area (mm²)	50x50	100x100	125x125	125x125
Write Speed [mm²/minute]	1	5	35	90
Address Grid [nm]	20	40	100	200
Edge Roughness [3σ,nm]	100	120	200	400
Line Width Uniformity [3σ,nm]	150	200	400	800
Alignment Measurement Accuracy [3σ,nm]	200	200	400	800

A new user training: Mike Crosby and Alan Burton

Technical support: Mike Crosby and Alan Burton

Risk assessment

Risk Assessment for Returning to Work during the Covid-19 Lockdown Easing Period