Excimer laser pulse broadening device based on double-beam splitting elements

Abstract

The invention discloses an excimer laser pulse broadening device based on double-beam splitting elements. The excimer laser pulse broadening device comprises the two beam splitting elements and a confocal resonant cavity based on two or more spherical reflectors. The first beam splitting element splits an incident laser beam into two beams, one beam of laser enters the confocal resonant cavity and is emitted into the second beam splitting element after generating a certain optical delay, and the other beam of laser is directly emitted into the second beam splitting element. The second beam splitting element further splits each incident laser beam into two beams, one beam of laser enters the confocal resonant cavity and returns to the first beam splitting element after generating a certain optical delay to be split further, the other beam of laser is converged with the other laser beams which are directly output after being split by the beam splitting elements or output after generating the optical delay through the confocal resonant cavity, and an output laser beam is formed. By means of the excimer laser pulse broadening device, the pulse broadening efficiency can be effectively improved, the peak power of the output laser beam output after broadening is reduced, and the service lives of the optical elements in an excimer laser optical system are prolonged.

Description

technical field [0001] The invention relates to the technical field of regulating the output parameters of an excimer laser, in particular to an excimer laser pulse stretching device based on a double beam splitting element. Background technique [0002] In VLSI manufacturing process, excimer laser lithography is one of the most important processes. At present, the main laser light sources used in semiconductor integrated circuit lithography equipment are argon fluoride (ArF) and krypton fluoride (KrF) excimer lasers, with output wavelengths of 193nm and 248nm, respectively. In lithography equipment, deep ultraviolet optical elements are widely used, including reflective optical elements, transmission optical elements, attenuation optical elements, etc., for shaping, transmission and control of 193nm or 248nm laser beams. The number of imaging objective lens elements in these optical elements is large, the manufacture is difficult, and the price is expensive. Under the con...

AI Technical Summary

Problems solved by technology

In these methods and devices, the stretching system based on a beam splitting element and a resonant cavity has either a low stretching ratio, or a poor output pulse shape after stretching

However, based on the series connection of two pulse stretching devices and the use of retroreflection for secondary stretching, there is a reflection loss for each reflection (for example, the reflectivity of a 193nm mirror is generally about 98%), resulting in a large energy loss.

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