一种改善准分子激光光束均匀性的新型均匀器

A Novel Homogenizer to Improve the Excimer Laser Beam Uniformity

准分子激光作为当前光刻装置的主要光源 ,要求其输出激光光束强度分布尽量均匀。为了改善其光束强度分布的均匀性 ,介绍了一种新型梯形棱镜式准分子激光光束均匀器。从理论上分析了其工作原理及设计加工要求 ,计算了最佳均匀截面位置 ,并与普通棱镜均匀器进行了比较。实验中根据经梯形棱镜折射后光束能量在中间较强光束的本底基础上进行三分互补叠加的原理 ,实现了其与普通棱镜均匀器在二维方向上的组合使用 ;通过调节均匀器与接收屏之间的距离并同时记录每一位置处光束光斑的能量分布改善情况 ,确定了最佳均匀截面位置并与理论计算相吻合。利用其改善准分子激光器输出光束强度的分布 ,起伏优于 4 % ,其均匀效果优于普通棱镜均匀器。

The excimer laser as the main light source of photolithographic device, whose energy distribution is required as homogeneous as possible. In order to improve the uniformity of its output energy density, this paper describes a novel trapezoid prism homogenizer. The working principle and the design requirement of the novel trapezoid prism are analyzed in theory. The optimal position of uniform section is calculated, and compared with the normal prism homogenizer. According to the theory that the beam energy refracted by the trapezoid prism is divided into 3 parts then overlapped in the base of the middle high energy, it realizes the use of association with the normal prism in two-dimensional. By means of adjusting the distance from homogenizer to receive screen, the optimal position of uniform section is determined which agreed with the theoretical calculation. Using this novel homogenizer ,the fluctuation of beam uniformity of XeCl excimer laser is less than 4%, it is better than that obtained by using a normal prism homogenizer.