Patent ID: 7514319

Claim:
A method of protecting a recessed region comprising: forming an insulating layer on a semiconductor substrate; forming an opening in the insulating layer; forming a protected layer on an upper surface of the insulating layer and a lower surface and sidewalls of the opening; forming a buffer layer on the protected layer, the buffer layer filling the recess and including a major portion of a copolymer polymerized with monomers including from 61 to 75 weight percent benzyl methacrylate; from 8 to 15 weight percent alkyl acrylic acid; with a balance being hydroxy alkyl methacrylate; removing an unexposed upper portion of the buffer layer using a developer solution to expose an upper portion of the protected layer, a remaining portion of the buffer layer substantially filling the recess; and removing the upper portion of the protected layer while a lower portion of the protect layer is protected by the remaining portion of the buffer layer, wherein the copolymer includes at least three monomers and has a structure corresponding to Formula I: wherein the variables L, M and N represent the relative molar fractions of the monomers and satisfy the expressions 0<L≦0.8; 0<M≦0.25; 0<N≦0.35; and L+M+N= 1; and, wherein R 1 , R 2 and R 3 are independently selected from C 1 -C 4 alkyls and derivatives thereof.