Korea Institute of Machinery & Materials (KIMM) (Daejeon, KR) earned U.S. Patent 7,645,133 for a ultra-violet (UV) nanoimprint lithography process and its apparatus capable of repeatedly fabricating nanostructures on a substrate (e.g. wafer, glass, quartz, etc.) with a stamp on which nanostructures are engraved. The UV nanoimprint lithography process and its apparatus are capable of yielding a large-area stamp at low cost, according to inventors Jun-Ho Jeong, HyonKee Sohn, Young-Suk Sim, Young-Jae Shin, Eung-Sug Lee, and Kyung-Hyun Whang.
The lithography process can be completed in one step by using the large-area stamp. The UV nanoimprint lithography process and its apparatus are capable of efficiently forming high-precision, high-quality nanostructures irrespective of any error of flatness. An error of flatness would normally result in non-uniform residual layer thickness, which can make the etching process difficult or unsuccessful.
A resist insufficiently pressed due to the error of flatness between a stamp and a substrate during imprinting can be further pressed by applying pressurized gas. Therefore, the insufficient filling of the resist, which may be generated when the nanostructures are fabricated on a large-area substrate (e.g. 8 inch wafer) in a single-step or step-and-repeat imprinting by using a large-area stamp (e.g. 5 in..times.5 in. stamp), can be prevented. Accordingly, it is possible to economically and efficiently form high-precision and high-quality nanostructures in a short time, says the inventors.
The UV nanoimprint lithography technology is an economical and effective method of fabricating nanostructures. It is multidisciplinary, and is supported by various technologies from such fields as nano-scale materials science, stamp fabrication, ant-adhesion layer, etching and measurements. The nano-scale precision control technology is regarded as crucial in the lithography process.
The UV nanoimprint lithography technology is applicable to ultra high-speed metal-oxide-semiconductor field-effect transistors (MOSFETs), metal-semiconductor field-effect transistors (MESFETs), high-density magnetic storage devices, high-density compact disks (CD), nano-scale metal-semiconductor-metal photodetectors (MSM PDs), and high-speed single-electron transistor memory, etc.
Korea Institute of Machinery & Materials’ UV nanoimprint lithography process and apparatus are able to repeatedly fabricate nanostructures on a substrate (wafer, UV-transparent plate) by using a stamp that is as large as or smaller than the substrate in size.
Korea Institute of Machinery & Materials’ apparatus includes a substrate chuck for mounting the substrate; a stamp made of UV-transparent materials and having more than two element stamps, wherein nanostructures are formed on the surface of each element stamp; a stamp chuck for mounting the stamp; a UV lamp unit for providing UV light to cure resist applied between the element stamps and the substrate; a moving unit for moving the substrate chuck or the stamp chuck to press the resist with the element stamps and substrate; and a pressure supply unit for applying pressurized gas to some selected regions of the substrate to help complete some incompletely filled element stamps.
