Elemental analysis of ion implantation added particles

Defect reduction programs often start by using size distributions and locations on wafers to give clues as to the origin of particles. The analysis of trends in the composition of the particles allows further information to be gathered. The morphology and elemental composition of particles added during implants using two Applied Materials implanters have been studied. The position and size of particles were first measured using a Tencor Surfscan 6200 and pre-and post-implant measurements used to determine which particles were added during the implant. The wafers were then taken to an analysis centre and placed in a SEM whose travelling stage could accept 200 mm wafers. Converting the co-ordinates measured in the Surfscan to those applicable to the SEM allowed the particles to be found, imaged and analysed by X-ray energy dispersive spectroscopy. This paper discusses these results and includes some examples that show how elemental identification has been used to identify particle sources, allowing them to be eliminated.