- Photolithography Technology
VILLIGEN, Switzerland, Nov. 9, 2010 — Eulitha AG has developed a photolithography technology for low-cost and high-throughput fabrication of photonic nanostructures. This solves a major problem faced in the fabrication of high-resolution photonic structures because standard photolithography equipment either lacks the required resolution, or its cost is prohibitively high. The patented technology enables the formation of periodic nanostructures over large areas for such applications as LEDs, solar cells and flat-screen displays.
The new technology, dubbed PHABLE (for Photonics Enabler), is a mask-based UV lithography method. Unlike currently available technologies, the PHABLE system forms an image that has practically unlimited depth of focus. Therefore nonflat substrates, such as LED wafers, can be patterned uniformly and reproducibly. It also allows combinations of different patterns such as linear diffraction gratings and arrays of holes on hexagonal or square grids to be printed using a single exposure onto a chip or a wafer. The resolution of the printed features can be as small as one quarter of the illumination wavelength. The masks required by PHABLE can be produced inexpensively using standard chromium-on-quartz mask-writing technology.
Photonic crystals needed for enhancing the light extraction efficiency of LEDs is one of the major applications of the new technology. Unlike the nanoimprint method that is commonly employed for this purpose, it avoids contact between the mask and the wafer, and it does not require consumable soft-stamps. Other applications also will benefit from this development, including nanowire-based LEDs and photovoltaic devices, heteroepitaxy on patterned silicon substrates and epitaxial lateral overgrowth used in blue-ray lasers. Wire-grid polarizers, as required for both LCD displays and projectors, may also be produced with the PHABLE technology.
Compatibility with conventional masks and UV-exposure processing will ensure a smooth adoption by the industry. Standard photoresists with suitable resolution and etch properties are available from multiple vendors. HB-LED and other device manufacturers will be able to rely on the usual, well-established sources for obtaining the required consumable materials so as to ensure a low-cost manufacturing process for their photonic nanostructures.
Eulitha now offers samples and wafer batch processing services to companies and researchers developing nanostructure-based products who are interested in taking advantage of this breakthrough technology. It is also currently offering laboratory lithography tools for 2- to 4-in. wafers that are suitable for product development. High-volume production tools with throughput in excess of 100 wafers per hour will be made available to manufacturers in the near future.
For more information, visit: www.eulitha.com
- A lithographic technique using an image produced by photography for printing on a print-nonprint, sectioned surface.
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