权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

High-resolution single-shot measurement of semi-transparent films by Chromatic Confocal Coherence Tomography (CCCT)

通过彩色共焦相干断层扫描 (CCCT) 对半透明薄膜进行高分辨率单次测量

基本信息

批准号：
282505242
负责人：
Professor Dr. Wolfgang Osten
金额：
--
依托单位：
Institut für Technische Optik (ITO)
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2015
资助国家：
德国
起止时间：
2014-12-31 至 2018-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/282505242?language=en
关键词：
resolution single shot measurement semi

项目摘要

In everyday production measurement tasks often occur where micro topographies are optically measured through contaminations (like oil films) or semitransparent films, or the actual properties of the film (e.g. paint layers) itself are of interest. For single surfaces, there are a number of methods which allow for a topography measurement with sub-micron precision. Some of them can be modified to sample a plurality of superposed interfaces as for the examples above. However, the measurement of the actual thickness of the films is disturbed by the unknown refractive index of the material. To achieve a correct measurement of the real thickness of the film, these modified topography methods depend on knowledge of this refractive index and/or intensive modelling. No method is known that is able to measure film thickness and refractive index simultaneously with a high axial and lateral resolution in a single-shot manner. To solve this problem, the new method of Chromatic Confocal Coherence Tomography (CCCT) is proposed. CCCT is based on the proven topography method of Chromatic Confocal Spectral Interferometry (CCSI), from which it shall evolve mainly by improved signal evaluation. The information of the surface under test is coded in two independent channels of the CCSI/CCCT signal: the confocal envelope as well as the interferometric wavelet. These two channels are affected by the refractive index in different ways: while the confocal channel assumes a too low film thickness, the interferometric channel measures optical pathlength and therefore a thickness higher than the real thickness. However, by suitable combination of both channels, a simultaneous measurement of both, refractive index and real film thickness, is possible.

在日常生产中，测量任务经常发生在通过污染（如油膜）或半透明膜或膜本身的实际性质（如油漆层）进行光学测量的微观形貌。对于单个表面，有许多方法可以实现亚微米精度的形貌测量。它们中的一些可以修改为对上述示例中的多个叠加接口进行采样。然而，薄膜实际厚度的测量受到未知材料折射率的干扰。为了实现对薄膜实际厚度的正确测量，这些改进的形貌方法依赖于对折射率的了解和/或密集的建模。目前还没有一种方法可以同时测量薄膜厚度和折射率，同时具有高轴向和横向分辨率。为了解决这一问题，提出了彩色共焦相干层析成像（CCCT）的新方法。CCCT是在彩色共聚焦光谱干涉法（CCSI）中成熟的地形方法的基础上发展起来的，其主要发展方向是改进信号评价。被测表面的信息被编码在CCSI/CCCT信号的两个独立通道中：共焦包络和干涉小波。这两种通道以不同的方式受到折射率的影响：共聚焦通道的薄膜厚度过低，干涉通道测量光程长度，因此厚度高于实际厚度。然而，通过两个通道的适当组合，可以同时测量折射率和实际薄膜厚度。