Patent ID: 8378317

Claim:
Ion implant apparatus comprising: a rotary scan assembly having an axis of rotation and a periphery; a plurality of substrate holders distributed about said periphery, said substrate holders being arranged to hold respective planar substrates, each having a respective geometric center on said periphery; and a beam line assembly to provide a beam of ions for implantation in said planar substrates on said holders, said beam line assembly being arranged to direct said beam along a final beam path; wherein said substrate holders are arranged to hold said respective planar substrates at a wafer tilt angle α s and at a wafer slope angle β s ; wherein said beam line assembly is arranged such that said final beam path has a beam tilt angle α b and a beam slope angle β b ; wherein 2°+Δβ≦β t ≦15°−Δβ where β t =β b −β s , 2*Δβ=(w x /πd)*360°, w x is the dimension of the wafer in the x-axis direction, and d is the diameter of said periphery of the rotary scan assembly, and F<0.5 where F=2α t *Δβ/(β t 2 −Δβ 2 +α t 2 ), and α t =α b −α s ; and wherein the total wafer angle φ≦45°, where sin 2 φ=cos 2 (α s )*sin 2 (β s )+sin 2 (α s ), and the total beam to substrate normal angle θ≦15°, where sin 2 θ=cos 2 (α t )*sin 2 (β t )+sin 2 (α t ).