Imprint lithography or nanoimprint lithography is a methodology for forming micro-scale and nano-scale structures on a substrate. Imprint lithography involves direct contact between a patterning tool (e.g., a mold, mask, template, etc.) and a substrate on which the structures are to be fabricated. The patterning tool is aligned with the substrate and then brought into contact with a surface of the substrate with some force. Consequently, the pattern of the patterning tool is imprinted on or impressed into a receiving surface of the substrate. The characteristics of the patterning tool largely determine the quality of the final structures and the fidelity of those structures to the desired pattern.
Unfortunately, during the imprint process, distortions often occur in the pattern as transferred to the receiving surface of the substrate. Mechanical deformations of the mold or substrate during the imprint process may distort the structures formed. For example, the flexure of a patterned region may cause patterns to become blurred, shifted, weakened, or otherwise distorted. Also, the shape, size, and density of features in a patterned area may limit the flow of photoresist or other chemicals used to form the structures, thereby causing the structures to be inconsistent, flawed, or absent.
Unfortunately, during the imprint process, distortions often occur in the pattern as transferred to the receiving surface of the substrate. Mechanical deformations of the mold or substrate during the imprint process may distort the structures formed. For example, the flexure of a patterned region may cause patterns to become blurred, shifted, weakened, or otherwise distorted. Also, the shape, size, and density of features in a patterned area may limit the flow of photoresist or other chemicals used to form the structures, thereby causing the structures to be inconsistent, flawed, or absent.
Hewlett-Packard Development Company, L.P. (Houston, TX) developed a method of contact lithography that includes predicting distortions likely to occur in transferring a pattern from a mold to a substrate during a contact lithography process; and modifying the mold to compensate for the distortions. According to inventors Wei Wu, Duncan Stewart, Shih-Yuan Wang and R. Stanley Williams in U.S. Patent 7,613,538, the contact lithography system includes a design subsystem configured to generate data describing a lithography pattern; an analysis subsystem configured to identify one or more distortions likely to occur when using a mold created from the data; and a mold modification subsystem configured to modify the data to compensate for the one or more distortions identified by the analysis subsystem.
Nanoimprint lithography is a candidate tool to replace photolithography at nanoscales below 32 nanometers and is capable of imprinting patterns as small as 5 to 10 nanometers as well as larger sizes.
The following figure illustrates nanoimprint stamps from NIL Technology and applications for nanoimprint lithography.
