Nondestructive Characterization of Polishing Damage in Silicon Wafers Using Modulated Reflectance Mapping

Temporal Behavior of Modulated Reflectance Signal in Silicon

“…As described by Opsal [1], theoretical calculations predict that the modulated reflectance signal should generally increase with the extent of damage, in the form of surface states or of lattice disorder in the ne ar surface region of the silicon wafer. These theoretical predictions are in agreement with experimental results on both incoming wafers and on ion-implanted wafers [3,13]. In Fig.…”

“…Our experiments on incoming bare silicon wafers show that typical modulated reflectance signals, lIR/R, at 1 MHz lie in the range of O.3-2x10-3 • Our data indicate that the higher signal levels are indicative of the small amount of residual damage present in the surface regions of the wafers that result from the chemipolishing and scrubbing processes used in the final stages of the manufacture of the wafers [3]. As described by Opsal [1], theoretical calculations predict that the modulated reflectance signal should generally increase with the extent of damage, in the form of surface states or of lattice disorder in the ne ar surface region of the silicon wafer.…”

“…These experimental conditions are described in the paper by Smith, Hahn and Arst in these proceedings [3]. Table 1 lists the major differences between our type of modulated optical reflectance experiments and the more conventional photoreflectance experiments [4][5][6][7][8][9][10].…”