TRANSMITTANCE CONTROLLED MASK (TCM) - ITS APPLICATION TO OPTICAL PROXIMITY CORRECTION AND TOPOGRAPHY

A new type of mask named a TCM (Transmittance Controlled Mask) is prop osed to correct for optical proximity and to overcome problems caused by topography. This mask, made from a conventional transmission mask w ith chromium patches on top where light attenuation is needed, is eval uated with different transmittances and is applied to the patterns whi ch require local light attenuation caused, by a resist thickness diffe rence or by light scattering over topography. Aerial image simulations and experiments were carried out comparatively from the view of image fidelity over topography, ft was found that good pattern formation wa s possible with a properly controlled transmittance mask regardless of the topography, which is a real situation in actual devices.