多层复合膜设计的原位椭偏监测

Abstract

Current developments in optical multilayer design and computation make it possible to calculate filters that satisfy the most demanding optical specifications. Some of the designs are highly sensitive to manufacturing errors and require accurate monitoring and control during thin film deposition. Ellipsometric monitoring enables the accurate deposition of any thickness, including very thin layers, and in situ measurement of both refractive index and thickness of the layers during deposition, which facilitate the subsequent real-time design reoptimisation. In this letter, a number of complex multilayer designs with the aid of ellipsometric monitoring are presented, including a laser notch plus band-blocker filter, dichroic filter, beamsplitter, and a wide-range broadband multiplayer antireflection coating. OCIS codes: 240.2130, 310.1860, 120.2130. doi: 10.3788/COL201008Sl.0044. In recent years, significant progress has been made in the field of multilayer optical coating design [1−5] . Nearly any optical filter specification can be designed theoretically, and a number of solutions have become available for very complex and challenging structures. Unfortunately, the required accuracy and reproducibility of the properties of a material for such structures are sometimes so high that mass production may be impossible, even in state-of-theart deposition systems. Hence, the accuracy of in situ monitoring and effective feedback control of the deposition process remain significant issues to be addressed. A number of well-established optical and non-optical techniques allow the monitoring and control of the layer deposition process [6] . The applicability of a particular method is dependent on the deposition technique and