The reciprocal space structures of Si backside rough surfaces were stu
died using an in-plane light scattering technique. A diode array detec
tor was used to collect the angular distribution of the scattered inte
nsity. The diffraction profiles are interpreted based on the theory of
diffraction from a self-affine rough surface. Roughness parameters su
ch as interface width, lateral correlation length, and the roughness e
xponent, are extracted from the profiles and are compared to that obta
ined by real space imaging techniques such as atomic force microscopy
and stylus profilometry. Factors that limit the accuracy of light scat
tering measurements are discussed. (C) 1998 American Institute of Phys
ics. [S0021-8979(98)08817-3].