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)。 As semiconductor manufacturing enters the era of 1xnm technology nodes, the measurement accuracy of the focus leveling system reaches tens of nanometers. In the nanoscale range, integrated circuit (IC) processes have a great impact on the accuracy of the focus leveling measurement. A focusing and leveling technology based on optical trigonometry and moire method is proposed. Two sets of moire fringes with phase difference of π are simultaneously imaged onto two detectors by using the spatial light splitting system. Through the normalized difference The method calculates the silicon height, which can effectively reduce the sensitivity of the focusing and leveling measurement technology to the IC technology, especially the light intensity change caused by the IC technology. Experimental results show that the system has a repeatability of 8nm (3σ) and a linearity of 18nm (3σ). The linearity change caused by this measurement technique is 15 nm (3σ) when the measured light intensity changes by 90%, and less than 1 nm (3σ) when the light intensity changes by 65%.