EVGNEWS Issue 3 2013

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UV Nanoimprint Solution for Nanopatterning 

The EVG® 720 system leverages an innovative UV nanoimprint lithography (UV-NIL) technology and EVG's materials expertise to enable mass manufacturing of micro- and nanoscale structures.  Capable of printing nanostructures as small as 40 nm over a large area with unmatched throughput and low cost of ownership, the EVG720 system is ideally suited for volume production of optics, photonics, light emitting diodes (LED), microfluidics and other bioMEMS devices, as well as advanced data storage.

EVG® 720 automated UV Nanoimprint System Features

  • Optimized for high throughput (more than 60 wph)
  • Integrated stamp manufacturing, which eliminates the need for stand-alone stamp replication systems and lowers cost of ownership
  • Inert gas printing
    • Better chemical resistance and adhesion
    • Faster cure speeds
    • Lower photo initiator levels
    • Increased production speeds
    • Reduced energy consumption and more consistent curing
  • Integrated electrostatic discharge reduces particle contamination
  • Optical clearance leaves no visible vacuum lines in the active imprint area
  • Maintenance friendly operation with no additional tubing and plumbing required
  • Top and/or bottom side alignment
  • Integrated separation of stamp and substrate -> structure geometry independent
  • Large area imprint (up to 150 mm square)
  • Open material platform for all commercially available imprint materials


UV Nanoimprint Applications

UV-NIL is a powerful next-generation lithography technique with almost unlimited structure size and geometry capabilities.  Endurance and marathon test runs on the EVG® 720 have demonstrated its high-volume manufacturing suitability for a wide range of applications such as:

Light Extraction

Sapphire substrates are commonly used for growing GaN films.  However, the large lattice mismatch between common sapphire substrates and the grown GaN layers causes a large number of threading dislocations at the interface.  These threading dislocations reduce the quality and lifetime of the LED chip.  Patterned sapphire or nano-patterned sapphire structured by UV-NIL is an elegant approach to solving this problem by altering the crystal growth orientation of the epitaxial film grown on pre-structured sapphire substrates.  In addition, these surface structures can display effects similar to surface roughening to enhance light extraction efficiency.

Thin Film Solar Cell

Power conversion efficiency in solar cells relies on the ability of a semiconductor material to absorb electromagnetic radiation.  Any radiation not absorbed within the semiconductor, which is  reflected, transmitted or absorbed within other materials (e.g. metallization), cannot be converted into extractable electrical power.  Thus, an important step in optimizing silicon solar cells is improving their optical characteristics.  Since micro- and nanostructures for photon management are of increasing importance in novel high-efficiency solar cell concepts, structuring techniques with up-scaling potential like UV-NIL play a key role in their realization.  UV-NIL enables industrial production of structures for front-side texturing, diffractive backside structures, periodic and aperiodic imprinted structures such as substrates for transparent conductive oxide (TCO) deposition, and increased P-N junction length arrays.

Biological Sensing

Most biological events begin at the nanometer level.  As a result, nano-scale manufacturing techniques can enable us to understand and manipulate fundamental biological processes, to improve the performance of modern medical devices and to increase the speed and sensitivity of assays and other analytical procedures for biomedicine.  Conventional lithography methods with low throughput do not meet the requirements for manufacturing new nano-scale medical and biological devices since a large number of identical devices-often with large patterned areas-must be produced at low cost to generate enough statistical data at the experimental stage and during clinical trials to reduce fatal device errors that lead to errors in the diagnosis and treatment of diseases.  With its flexibility, easily accessibility and scalability for patterning micro- and nanometer-scale features, UV-NIL is one of the most promising lithography technologies for biomedical applications. 

 

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EVG® 720 Automated UV-NIL System (Click to enlarge)  

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Photograph of fully populated 6” imprinted Si substrate

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SEM Image of 500 nm imprinted patterned sapphire structures