Laser metrology supports a wide range of industries to accurately measure physical dimensions. It has some critical applications in the medical sector, the semiconductor industries, and aerospace and automotive industries. Laser metrology includes an array of different methods to achieve accurate optical measurements by using laser beams. Laser metrology must overcome certain challenges in achieving accurate measurements. In this article, we review the challenges in laser metrology and what we think is the ideal solution for laser metrology.
Challenges in Laser Metrology
Accuracy is one of the major challenges in laser metrology, requiring the use of advanced methods and components to ensure accuracy and minimize noise. We often need complex optical solutions to obtain high-resolution measurements. For instance, extreme ultraviolet lithography is an advanced lithography technique for creating tiny features in semiconductor devices.
To measure these features, we need optical solutions such as laser metrology scanning. This type of laser metrology usually involves the use of elongated focus DOEs or diffractive optical elements to expand the range of detection and ensure high resolution.
Diffractive Optics: A Good Fit for Laser Metrology
The unique properties of diffractive optics benefit laser metrology in various ways, including improving the efficiency and performance of the laser system. The laser beams that laser metrology uses to measure physical dimensions are not natural laser beams. This is because the intensity distribution pattern that natural laser beams display is not appropriate for industrial laser applications. These beams show a Gaussian pattern for intensity distribution. In this intensity pattern, the light energy slowly declines towards the edges, causing a noteworthy energy loss and cross-talk .
Laser metrology uses diffractive optics to shape or modify the input laser beam’s intensity profile so that the output beam shows a uniform intensity distribution pattern. A diffractive optical element or DOE is one type of optical component that performs as a beam shaper and shapes the intensity profile of the incident beams by using the principle of diffraction. A hat beam shaper modifies the intensity profile into a top hat distribution pattern.
There are several advantages of using diffractive optical elements in laser metrology, such as
- Because of high angular accuracy and tight tolerances, diffractive optical elements ensure high precision in optical measurements.
- Diffractive optical elements allow customers to customize them according to the desired field of illumination. In simple words, one can customize DOEs to achieve an intensity pattern of any geometrical shape, including line, square, round, rectangular, all having a top hat pattern of intensity.
- These optical components are simple to integrate into any laser system.
- Lastly, DOEs are highly stable and durable with high LDT.
Therefore, diffractive optics offer an absolute solution for laser metrology and boost laser metrology applications in different industries to precisely measure physical parameters and maintain high product quality.