In-Situ Determination of Multiple Properties of Films Using Hot- Stage Optical Microscopy and Micromachined Test Structures

Inhalt:
The sufficient well control and determination of material properties of films is vital for the design and fabrication of microelectromechanical systems, integrated circuit and photoelectric devices. Generally, the material properties of films from any of deposition techniques are process-, temperature- and size-dependent. Unfortunately, the database for such properties has not been fully established. Even though there are well-documented properties of bulk materials, they may not be directly applicable to thin films. A broad array of methods for material property extraction of films has been proposed in the literature, but most of them are designed for one property extraction alone. Only some of them have the capability of multiple properties extraction, but which requires complex test structures, expensive and not easily available experimental apparatus and special fixtures. In this paper, we propose in-situ determination of multiple properties of films using hot-stage optical microscopy and test structures. The experimental apparatus include a conventional optical microscope (OM) equipped with a hot stage and a Charge-Coupled Device (CCD), which are readily available in a laboratory. With this hot stage, an OM enables in-situ investigations of film specimens at elevated temperatures that closely resemble their true service condition. The CCD is connected with an image analysis system. The test structures can be fabricated by simple surface micromachining techniques and in-situ along with active devices on the same chip for monitoring the properties of the film, and they occupy a very small area on die site. The different properties of the film can be validated via independent measurement on the same test structure.