Rapid generation of integrated circuit patterns and high-fidelity fabrication of 3D photonic crystals
Abstract
Integrated circuits are one of the most important building blocks for our society, and their transistor gate patterns, which determine their functionalities, usually consist of multivertex paths whose line segments are along two orthogonal directions. Such patterns are some-times called Manhattan structures and are typically designed to achieve the highest packing density with a given line width. Owing to their arbitrary shapes, these patterns are pre-dominantly generated via electron-beam lithography, a serial process that is inherently slow compared to parallel processes. Moreover, throughput is further reduced with the necessity of proximity correction in electron-beam lithography. On the other hand, interference lithography is a low-cost, parallel process that can achieve small line widths and pitches, yet the achievable patterns are limited to gratings or other periodic structures. In this thesis we propose to synthesize arbitrary Manhattan structures from regular structures such as gratings via cutting and stitching. We demonstrate the cutting and stitching of large-area, highly-smooth gratings formed by interference lithography and orientation dependent etch of silicon. Our method could significantly reduce the writing time in electron-beam lithography for pattern generation and requires no proximity correction. 3D Photonic crystals (PhCs) offer unprecedented opportunities for miniaturization and integration of optical devices. Microcavities in 3D PhCs are capable of confining light in virtually any materials, including low-index materials such as air. Devices based on 3D PhCs may lead to exciting demonstrations in enhanced optical detection of chemical warfare agents, or novel mode-locked lasers. However, experimentally realizing such cavities with high-fidelity to design has been a significant challenge. In this thesis we present the fabrication of microcavities in 3D PhCs. Using advanced e-beam lithography, we have achieved a six-layer, high quality 3D PhC with designed hollow microcavities via layer-by-layer approach and wafer bonding, and preliminary optical results are consistent with numerical simulations.
Degree
Ph.D.
Advisors
Qi, Purdue University.
Subject Area
Electrical engineering
Off-Campus Purdue Users:
To access this dissertation, please log in to our
proxy server.