A Novel Optical Component for the Development of an Integrated Interferometric System

Optical interferometry is a well established technique for high resolution displacement measurements. It is commonly used in the semiconductor industry as a sub-system of manufacturing and metrology tools. As the industry progresses, the tools continue to evolve, requiring the concomitant reduction of size and cost in sensors. Existing interferometric systems are bulky and therefore difficult to incorporate in equipment. Efforts are ongoing to miniaturize these systems but with optical components (beam splitters, detectors and lasers) still in the millimeter range, it is difficult to realize ultra compact systems. Thus, it is imperative to focus on development of micron scale components that would provide the necessary high spatial resolution in a compact format. The focus of this paper is on the development of a micron size optical component that combines multiple optical elements and can be integrated with VCSELs at the wafer level to yield a compact, low cost interferometric system. The design and development of this component containing the beam splitter and reference mirror will be presented including the investigation of suitable polymeric materials with desirable optical properties and appropriate fabrication techniques. Preliminary optical measurements of the integrated system will also be demonstrated. This approach has the potential to impact the next generation of micron scale interferometers as precise position/proximity sensors.