Detection and identification of foreign bodies in polymer parts for use in semiconductor manufacturing

This paper presents an approach enabling localization and identification of foreign bodies in polymer materials applying a combined approach of x-ray imaging, imaging microscopy, optical coherence tomography and Raman imaging spectroscopy. The reliable detection of even small foreign bodies in polymer materials and parts designated for use in semiconductor manufacturing and processing machines is essential. Foreign bodies can in particular be metals, burnt particles of the polymer of the work piece, or intact or degenerated foreign polymers. In either case, all surfaces of e.g. a handling equipment that get in contact with the semiconductor material or process solutions have to be free of foreign bodies to ensure the integrity of the manufacturing process. Size, localization and material of the foreign body are main parameters that decide if a work piece has to be rejected. Current inspection systems may enable the localization of the foreign body, but are not capable of identifying the material and structure of the foreign body; many components with inclusions are therefore rejected as a precaution. This work aims towards the development of a combined sensor approach as part of an automatic quality assurance procedure which can be integrated in the fabrication process. X-ray imaging is used to identify metal foreign bodies. Imaging microscopy is used to detect foreign bodies on the surface of the polymer parts. Optical coherence tomography is used to measure the three-dimensional position and size of the foreign bodies. Raman imaging spectroscopy is used to identify the composition of the foreign bodies if they are located on the surface.