Low-Cost Method for Repeatable Nano-Scale Patterning Using Pulsed Lasers

Abstract

Researchers at the University of Central Florida have developed a method that enables manufacturers to fabricate structures 50 nanometers (nm) or less on the surface of solid materials. The low-cost, repeatable method overcomes the shortcomings of existing technologies that suffer from stochastic effects and fluctuations in laser energy.

Ultrashort laser pulses (such as pulses lasting picoseconds, femtoseconds or lower) can produce nanometer-scale structures with high resolution due to so-called “cold ablation” that reduces or completely avoids detrimental thermal effects. However, this technique has poor repeatability because it depends on near-threshold processes that are stochastic. Though nano-scale features may also be fabricated through multi-photon absorption in large-bandgap materials, fluctuations in the laser energy may offset the benefits of the large bandgap. Thus, sub-100 nm structures cannot be fabricated reproducibly using such methods.

The UCF invention offers a solution for laser patterning using pulsed laser bursts. The technology gives manufacturers a reliable, repeatable way to fabricate features with nanoscale precision. With future development, it is possible to create large amounts of nanostructures within a short time, thus increasing throughput beyond existing technologies.

Technical Details

The UCF invention comprises systems and methods based on selective excitation of precursor sites in a specific pattern. In one example, the system includes a burst generator located between the laser source and an objective lens that focuses an illumination beam onto a sample. The burst generator produces a series of pulse bursts from one or more laser pulses. Each pulse burst includes two or more laser pulses with intensities that are lower than the known damage threshold of the sample. The intensities, polarizations, or the inter-pulse spacings of the pulse bursts are selected via the burst generator to successively excite the precursor sites. This modifies the sample in a feature pattern based on the precursor pattern.

The sample can be any type of material, such as glass, metal or semiconductive. A precursor site may include a defect site, a dopant, a color center, or a self-trapped exciton (STE), for example. The burst generator comprises at least one of one or more Michelson interferometers, one or more Fabry-Perot interferometers, or one or more stacked birefringent crystals.

Partnering Opportunity

The research team is looking for partners to develop the technology further for commercialization.

Stage of Development

Prototype available.

Benefit

Market Application