Provided are methods of forming an ion implanted region in a semiconductor device. The methods comprise: (a) providing a semiconductor substrate having a plurality of regions to be ion implanted; (b) forming a photoresist pattern on the semiconductor substrate, wherein the photoresist pattern is formed from a chemically amplified photoresist composition comprising a matrix polymer having acid labile groups, a photoacid generator and a solvent; (c) coating a descumming composition over the photoresist pattern, wherein the descumming composition comprises: a matrix polymer; a free acid; and a solvent; (d) heating the coated semiconductor substrate; (e) contacting the coated semiconductor substrate with a rinsing agent to remove residual descumming composition and scum from the substrate; and (f) ion implanting the plurality of regions of the semiconductor substrate using the photoresist pattern as an implant mask. The methods find particular applicability in the manufacture of semiconductor devices.