Planar Staining Technique for Photoresist Related Implantation Issue

Ion implantation process is a critical step in the microfabrication of thin film transistors. Defects due to the implantation process not only seriously degrade the performance of the devices, but also are hardly detected via traditional electron microscopic techniques alone, including scanning electron microscopy (SEM), Transmission Electron Microscopy (TEM) and focused ion beam (FIB), etc. Wet chemical stain technique, such as junction stain, is an effective method to identify the defect area because of the different etching rates caused by ion implantation concentration. In this paper, a photoresist related implantation issue was reported, and a planar staining technique was developed to directly identify the defects from the suspected failure area by combining the junction stain and SEM techniques. More importantly, the planar staining technique for the photoresist related implantation issues is convenient, time-saving, and effective, as there is no need to prepare cross-section samples for SEM observation.