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DPSS Lasers for Laser Interference Lithography

What is laser interference lithography?

Laser interference lithography is a technique used to create extremely tiny patterns on a surface, often used in the fabrication of semiconductors and other micro and nanoelectronics

 

A laser beam is split in two, then both beams are directed onto a photosensitive material (like a photoresist) at slightly different angles. Where the two overlap, their light waves can either reinforce (constructive interference) or cancel each other out (destructive interference). This creates a pattern of alternating high and low intensity areas on the photoresist.

By controlling the laser beams and the properties of the photoresist, a pattern of exposed and unexposed regions can be created on the surface. This can then be used to etch the underlying material through a chemical process, leaving behind the desired tiny pattern.

Why is Laser Interference Lithography Important?

High Resolution

By exploiting the nature of light, laser interference lithography can achieve much smaller feature sizes compared to traditional photolithography techniques, creating the iontricate circuits needed in modern electronic devices.

Flexibility

This technique can create a wide variety of patterns, including lines, grids, dots and more,  by adjusting the configuration of the laser beams.

Scalability

Laser interference lithography can be used to create patterns over large areas, making it suitable for mass production of electronic devices.

As technology advances, the technique is expected to play an ever-increasing role in the future of micro and nanofabrication.

Why Lasers are crucial for Laser Interference Lithography

Coherence

Conventional light sources emit light waves in random phases. For laser interference lithography, the two beams need to be coherent, that is, perfectly synchronised in both frequency and phase. Lasers are the ideal source, producing highly coherent light. Skylark NX lasers boast an ultra-narrow linewidth.

Monochromaticity

Interference relies on the constructive and destructive interaction of light waves. Lasers provide a monochromatic light source, meaning all the light waves have the same wavelength. this allows for precise control over the interferometric pattern and the resulting feature size. Skylark NX lasers boast an ultra-stable wavelength.

High intensity

The intensity of the light dictates the depth of the pattern etched into the photoresist. Lasers offer. high power and focus, enabling the creation of deep, well-defined patterns on the surface. Skylark NX lasers boast an ultra-stable output power.

Spatial coherence

Regular light sources can spread out as they travel. Lasers are spatially coherent, meaning their light waves travel in a well-defined direction. This allows for precise control of the beam overlap area on the photoresist, crucial for creating clean and uniform patterns. Skylark NX lasers boast an ultra-stable wavelength.

Controllability

The properties of the laser beam, such as its intensity and wavelength, can be precisely controlled. This allows the beam overlap area to be fine-tuned so the interference pattern can be tailored to the exact size and shape required.

Skylark Lasers are ideal for interference lithography

The Skylark Lasers NX series delivers wavelengths at 320 and 349 nm - offering ultra-low noise < 0.1% RMS, and ultra-narrow linewidths < 0.5 MHz while maintaining up to 200 mW output power in the UV range.

The 320 and 349 nm wavelengths are compatible with industry standard UV photoresists, and with coherence lengths > 100 m, they are the ideal laser source for your interference lithography application.

our ultra-stable, high precision laser sources support our customers' work across several interferometric lithography applications.

 

  • Nanofabrication of high-resolution periodic structures

  • Diffraction grating fabrication

  • Diffractive optical element (DOE) fabrication

  • Optical filter fabrication

  • Nanophotonic applications

Skylark Lasers DPSS NX Series
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