An Excimer Laser Pulse Stretching Device Based on Dual Beam Splitting Elements

Abstract

The invention discloses an excimer laser pulse stretching device based on double beam splitting elements, which includes two beam splitting elements pointing to the same and a confocal resonant cavity based on two or more spherical mirrors. The first beam-splitting element splits the incident laser beam into two beams, one beam enters the confocal resonator, and after a certain optical delay, it enters the second beam-splitting element, and the other beam directly enters the second beam-splitting element. Bundle elements. The second beam splitting element further splits each incident beam into two beams, one of which enters the optical resonant cavity and generates a certain optical delay and then returns to the first beam splitting element for further splitting, and the other beam is separated from the other The beams that are directly output after being split by the beam splitting element or output after being optically delayed by the confocal resonator are combined to form an output beam. The invention can effectively improve the pulse stretching efficiency, reduce the peak power of the output laser beam after stretching, and improve the service life of the optical elements in the excimer laser optical system.

Description

Technical field [0001] The invention relates to the technical field of aligning the output parameters of a molecular laser for regulation, in particular to an excimer laser pulse stretching device based on a double beam splitting element. Background technique [0002] In the 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 the lithography machine equipment, a large number of deep ultraviolet optical elements, including reflective optical elements, transmissive optical elements, attenuating optical elements, etc., are used to shape, transmit and control the 193nm or 248nm laser beam. The imaging objective lens elements in these optical elements are large in number, difficult to manufacture, and expensive. ...

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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