Combined interference and scanning force microscope

摘要

A novel compact sensor head combining optical interference and scanning probe microscopy in a single instrument has been developed. The instrument is able to perform complementary quantitative measurements, combining fast nondestructive three-dimensional surface analysis with high lateral resolution imaging. The sensor head has been integrated within the architecture of a commercial interference microscope. The combined instrument makes available both the acquisition software and the hardware interface of the commercial microscope. Furthermore, the use of an optical fiber to transmit light from an external laser removes a major heat source from the measurement environment and its small diameter makes aperture correction unnecessary. Lateral resolution is extended by the attachment of a specially designed scanning probe microscope (SPM) module to the microscope objective. The SPM unit is based upon piezo-resistive cantilever technology and is self-sensing to ensure a compact design that satisfies working distance criteria defined by the optics. A major benefit of the system, in terms of a quantitative nano-metrology, is the possibility to perform a traceable and direct calibration of the SPM module. Ellipsometry has been used to quantify the impact of material differences upon interference height data. Corrected values show excellent agreement with SPM height data.