Spectral control device

Abstract

The invention relates to a spectral control device which is applied to a master oscillator power-amplifier dual-cavity structure excimer laser. The spectral control device comprises two stages of linewidth narrowing modules; the first-stage linewidth narrowing module and an output coupling device are adopted as two end mirrors and are respectively arranged at two ends of a laser discharge cavity; the first-stage linewidth narrowing module, the output coupling device and the laser discharge cavity form a main oscillation resonant cavity of the excimer laser, so that first-stage linewidth narrowed laser output with a certain output energy can be formed; and the second-stage linewidth narrowing module is arranged in a transmission light path between the main oscillation resonant cavity of the excimer laser and an energy amplification cavity, and can perform linewidth modulation on the first-stage linewidth narrowed laser output with a certain output energy which is outputted by the main oscillation resonant cavity, so that second-stage linewidth narrowed laser output can be formed. With the spectral control device of the invention adopted, problems such as low degree of freedom of spectral control, high spectral tuning difficulty, poor spectral tuning flexibility and high possibility of optical component damage of an existing single-spectrum control device can be solved.

Description

technical field [0001] The invention relates to a spectrum control device, in particular to a spectrum control device of an excimer laser. Background technique [0002] In the process of research and development of laser technology, the problem of spectrum control is often involved. Effective control of laser wavelength and laser line width can obtain the output of laser light source system characteristic indicators for different application requirements. [0003] Taking the excimer laser system as an example, for lithography applications, in order to ensure the fineness of semiconductor silicon chip patterning and design integration, considering the related factors of lithography node realization, it is often required that the lithography light source has a narrow laser line wide output. [0004] In the relevant lithography excimer laser light source system structure, the line width narrowing module is often used to complete the narrowing control of the laser line width of...

AI Technical Summary

Problems solved by technology

[0007] Due to the nearly thousand-fold difference between the narrowing of the spectrum required for lithography (~0.5pm) and the laser free oscillation spectrum (~500pm), in the case of a single linewidth narrowing module, the ultra-fine narrowing of the laser linewidth It will cause a large loss of laser energy, resulting in lower laser output of the main oscillator resonator, narrowing the spectrum and reducing the efficiency of the output laser, so that the energy output synchronously by the main oscillator resonator under the condition of ensuring the narrow linewidth of the output target is lower. Low, considering the overall light source energy output index, this also puts forward higher requirements for the design and implementation of the energy amplification mechanism

[0008] Due to the existing spectrum control method, the single linewidth narrowing module is completely located in the main oscillation resonator, and the flexibility of spectrum tuning is poor. The corresponding spectrum tuning will cause the main oscillation resonator, the energy amplification cavity and their mutual energy-spectrum- The mutual coupling and linkage of multiple factors such as pulse width-beam quality will bring great difficulties to the reasonable tuning of the energy-linewidth optimized output of the main oscillation resonator. Great impact, which greatly affects the stability and reliability of the whole machine system operation

At the same time, when the linewidth narrowing module composed of multiple optical elements acts as the end mirror of the main oscillation resonator, the multi-degree-of-freedom tuning of multiple elements will have a greater impact on the laser oscillation mode selection output of the main oscillation resonator

In addition, the transmission of high-energy laser in the deep ultraviolet band in the main oscillation resonator will cause high concentration of ozone, which will also greatly affect the output level of laser energy and laser line width of the main oscillation resonator

[0009] Due to the high laser energy density inside the main oscillation resonator, the linewidth narrowing module integrated by multiple components (to ensure the target linewidth) is completely located in the main oscillation resonator, which will also cause local high-energy laser irradiation hot spots, increasing Damage chance of optical components

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