A Scanner Matching Method based on Interior-point BFGS Algorithm

A scanner matching method based on interior-point BFGS algorithm is proposed. This method minimizes the critical dimension (CD) differences by optimizing parameters of illumination sources, including inner partial coherence factor, outer partial coherence factor, numerical aperture and opening angle of illumination poles for dipole and quadrupole sources. Simulations of scanner matching are performed. Scanners with annular, dipole and quadrupole sources are matched in the simulations. Through-pitch Line/space patterns are used as the matching targets. The results of these simulations show that, the proposed method can reduce root-mean-square of CD differences after matching. In the majority of the simulation cases, the proposed method is faster than methods based on the Levenberg-Marquardt algorithm, and could even achieve better result. Analyses on the proposed method are given.