软X射线Mo/B_4C多层膜应力和热稳定性研究

为了实现7nm波段Mo/B4C多层膜反射镜元件的制备,研究了不同退火方式对Mo/B4C多层膜应力和热稳定性的影响。首先,采用直流磁控溅射方法分别基于石英和硅基板制作Mo/B4C多层膜样品,设计周期为3.58nm、周期数为60,Mo膜层厚度与周期的比值为0.4。其次,采用不同的退火方式对所制作的样品进行退火实验,最高退火温度500℃。最后,分别采用X射线掠入射反射、X射线散射和光学干涉仪的方法对退火前后的Mo/B4C多层膜的周期、界面粗糙度和应力进行测试。测试结果表明采用真空退火方式能够有效降低Mo/B4C多层膜的应力,且退火前后Mo/B4C多层膜的周期和界面粗糙度无明显变化,证明Mo/B4C多层膜在500℃以内具有很好的热稳定性。

Stress and thermal properties of Mo/B4C multilayers in soft X-rays

In order to prepare the Mo/B4C multilayer mirrors in 7 nm, the stress and thermal stability mechanism in Mo/B4C multilayers with different annealing ways was studied. Firstly, the periodic Mo/B4C multilayers with 60 bilayers were deposited in the fused silica substrate and Si substrate by DC magnetron sputtering method, the design periodic thickness(D) is 3.58 nm, the ratio of the thickness of the Mo with D is 0.4. Secondly, the prepared samples were annealed with various annealing ways, the maximum annealing temperature was 500 ℃. Finally, the period, the interface roughness and stress were measured using X-ray grazing incidence reflection, X-ray scattering and optical interferometer before and after annealing, respectively. The test results show that the vacuum annealing method can effectively reduce the stress of Mo/B4C multilayers, and the period and interface roughness of the Mo/B4C multilayers have no significant changes, which prove the Mo/B4C multilayers have good thermal stability within 500 ℃.