Lithography

Micro-nano lithography is necessary for the creation of the nanoscale components featured in nearly all modern technologies and ANFF offers several different lithographic techniques and instruments.

 

Lithography is the process by which a pattern is written or transferred to a substrate. The process can be physical in nature, utilising a ‘stamp’ to press structures into a softer material, or chemical using light, ions or electron energy to write into photo and electron sensitive resists.

ANFF-SA offers several different lithographic techniques and instruments, including:

Spin coating and wafer development

 

The process: A crucial element in any lithographic process, coating wafers with photoresist and subsequently developing them, allows for the mold features to be faithfully replicated on the wafers. 

 

The instrument: Suss Delta 80

Photolithography

 

The process: Photolithography is a process used to transfer a pattern from a mask to a photosensitive resist-coated substrate. The photoresist is then developed in a solution to remove the unwanted material, after which, the substrate can move onto the next process such as metal deposition or etching.

 

The uses: Photolithography is central to most micro and nanofabrication applications including microfluidics and cantilever fabrication. The minimum feature sized achieved at ANFF-SA using mask lithography is 1µm with a subsequent metal lift-off process.

 

The instrument: EVG 620

PDMS soft lithography

 

The process: Soft lithography is a process by which rigid master mold structures, typically silicon/SU8, are replicated in an elastomeric material known as polydimethylsiloxane (PDMS). Silicon is exposed to the desired pattern using photoresist, after which the patterned structure is treated with an anti-stick coating and liquid PDMS is poured over it. Once cured, "daughter" devices can be removed from the mold whose features match that of the master.

 

The uses: Useful for its flexibility, PDMS is ideal in applications involving surfaces which are not flat. PDMS can also be used in microfluidic applications, where rapid prototyping is important. It is also biocompatible and oxygen permeable making it useful in a broad range of bio-applications, and it is optically transparent.

The instrument: ANFF-SA has a dedicated PDMS laboratory Sylgard 184

Hot embossing

The process: Hot embossing is a pattern-transfer technique, involving the application of pressure and heat to a polymeric or resist-coated substrate, placed in contact with a master mold. This allows the relief features on the mold to be transferred faithfully. Hot embossing achieves fast patterning at a resolution of 50nm.

The uses: This technique addresses a wide range of applications, from polymer-based lab-on-chip systems, where imprinting is performed on thick polymers substrates, for the fabrication of sub 50nm features for bio-sensing or data recording applications, as well as microfluidics, MEMS, optoelectronics, packaging and SOI production.

 

The instrument: EVG 520HE

Nano imprint lithography

 

The process: Nano imprint lithography involves a pattern-transfer technique similar to hot embossing, though it is achieved by using a UV curable resist and subjecting the mold to UV light, rather than heat and pressure.

 

The uses: This is useful in the creation of patterned media, optics, and lab on a chip systems.

 

The instrumentsEVG 520HE or EVG620

Contact ANFF-SA Facility Manager Simon Doe on +61 8 8302 5226 for further information or to make a booking. 

View our full instrument list