Residue formation in the removal of ion implanted photoresist

The phenomenon of residue formation after the stripping process of ion implanted photoresist and the dependence of the residue formation on ion source and dose level have been investigated. To analyze residues, several surface analysis tools have been used. Implant of Ar+, BF2+, and P+ and several kinds of dose levels have been used for ion implantation on photoresist masked samples. It was found that the formation of residues strongly depends on ion source and dose level. Residues have been detected only in the case of phosphorus ion at the dose of 6E15 ions/cm(2) and above, where phosphorus ion can be reacted with oxygen and easily form phosphorus oxide. AES analysis of residues show that the surface of residue is covered with PxOy/hydrocarbon composition layer. The results indicate that if implanted ion source produce inorganic compounds through the reaction with oxygen radical, it is difficult to remove the residues completely with normal PR stripping process.