types of lithographic masks. Template wear is reduced with proper use of an anti-adhesion FDTS monolayer coating on a stamp. A very efficient and precise AFM based method for characterizing the degradation of PDMS stamps enables to optimize materials and processes in order to minimize wear. Other Future applications of nanoimprint lithography may involve the use of porous low-κ materials. These materials are not stiff and, as part of the substrate, are readily damaged mechanically by the pressure of the imprint process. Removal of residual layers A key characteristic of nanoimprint lithography (except for electrochemical nanoimprinting) is the residual layer following the imprint process. It is preferable to have thick enough residual layers to support alignment and throughput and low defects. However, this renders the nanoimprint lithography step less critical for critical dimension (CD) control than the etch step used to remove the residual layer. Hence, it is important to consider the residual layer removal an integrated part of the overall nanoimprint patterning process. In a sense, the residual layer etch is similar to the develop process in conventional lithography. It has been proposed to combine photolithography and nanoimprint lithography techniques in one step in order to eliminate the residual layer. Proximity effects Nanoimprint lithography relies on displacing polymer. This could lead to systematic effects over long distances. For example, a large, dense array of protrusions will displace significantly more polymer than an isolated protrusion. Depending on the distance of this isolated protrusion from the array, the isolated feature may not imprint correctly due to polymer displacement and thickening. Resist holes can form in between groups of protrusions. Likewise, wider depressions in the template do not fill up with as much polymer as narrower depressions, resulting in misshapen wide lines. In addition, a depression at the edge of a large array fills up much earlier than one located in the center of the array, resulting in within-array uniformity issues. 3D-patterning A unique benefit of nanoimprint lithography is the ability to pattern 3D structures, such as damascene interconnects and T-gates, in fewer steps than required for conventional lithography. This is achieved by building the T-shape into the protrusion on the template. Similarly, nanoimprint lithography can be used to replicate 3D structures created using Focused Ion Beam. Although the area that can be patterned using Focused Ion Beam is limited, it can be used, for example to imprint structures on the edge