The Effect of Charging on Pattern Placement Accuracy in E-Beam Lithography.

An analysis of overlay measurements for wafers patterned by Direct Write suggested that resist charging can induce pattern placement errors during e-beam lithography. This paper outlines a methodology for measuring charge-induced beam deflection. Experiments confirmed that the magnitude of the effect scales linearly with trilevel thickness. Increasing the accelerating voltage of the electron beam was shown to reduce beam deflection. Also, Ar ion implantation of the trilevel and the use of a metal trilevel were demonstrated to eliminate the effect of charging.