基于空间分光的纳米级调焦调平测量技术  

Nanoscale Focusing and Leveling Measurement Technology Based on Optical Spatial Split

作　　者：孙裕文[1,2,3] 李世光[1,2,3] 宗明成[1,2] 

机构地区：[1]中国科学院微电子研究所,北京100029 [2]中国科学院微电子研究所微电子器件与集成技术重点实验室,北京100029 [3]中国科学院大学,北京100049

出　　处：《光学学报》2016年第5期97-104,共8页Acta Optica Sinica

基　　金：国家科技重大专项(2012ZX02701004)

摘　　要：随着半导体制造步入1xnm技术节点时代,调焦调平系统的测量精度达到几十纳米。在纳米尺度范围内,集成电路(IC)工艺对调焦调平测量精度的影响很大。提出一种基于光学三角法和叠栅条纹法的调焦调平测量技术,利用空间分光系统将两组位相差为π的叠栅条纹同时成像到两个探测器上,通过归一化差分的方法计算硅片高度,可有效降低调焦调平测量技术对IC工艺的敏感度,尤其是IC工艺导致的光强变化的敏感性。实验结果表明,该系统测量重复性精度为8nm(3σ),线性精度为18nm(3σ)。当测量光强变化达90%时,该测量技术引起的线性精度变化为15nm(3σ);当光强变化为65%时,线性精度变化小于1nm(3σ)。With the development of semiconductor manufacturing to 1xnm technological node,the measurement accuracy of the focusing and leveling system is down to several tens of nanometers.In the range of nanoscale,integrated circuit（IC）process plays an important impact on the measurement accuracy of the focusing and leveling system.A kind of focusing and leveling measurement technology based on optical triangulation and moiréfringes method is proposed.Two sets of moiréfringes withπphase difference are imaged onto two detectors using the spatial splitting system.The height of wafer is calculated by normalized differential method.The sensitivity of the system on the IC process,especially on the light intensity fluctuations is reduced.Experimental results show that the measurement repeatability of the system is 8nm（3σ）and the linear accuracy is 18nm（3σ）.When the light intensity fluctuates 90%,the linear accuracy changes 15nm（3σ）.When the light intensity fluctuates 65%,the linear accuracy changes less than 1nm（3σ）.

关 键 词：测量 调焦调平 空间分光 硅片高度 集成电路工艺 

分 类 号：O436[机械工程—光学工程]