3D patterning for bridges and T-gates

In contrast to the 2D solution, the correction for 3D patterning is complex and application dependent. The 3D applications, such as T-gates and bridges focus on CD control. Typical processes include bi- or tri-layer resists at different resist sensitivities that are exposed selectively using appropriate exposure doses. These exposures interact with each other, and are obscured by electron scattering, thus high resolution PEC and 3D PEC needs to be applied.