Electro-optic adaptive microlens

The goal of the present research was to demonstrate the viability of an electro-optic adaptive microlens (EOAM) system in imaging applications requiring broadband illumination in the visible region. Previous works illustrate devices that are adaptive optics but are limited in capability. Most have been designed and optimized for a particular wavelength and many of them are polarization dependent. An adaptive optical system that will function over a broadband of visible wavelengths will be useful in many imaging applications. The tasks completed for EOAM system design and build required understanding and implementation of the imaging theory, the materials\u27 properties, the control voltages, the fabrication processes, and finally understanding and implementation of the imaging theory for testing. Single cell transmission devices were used for initial characterization of the polymer-dispersed liquid crystal (PDLC) process. Three iterations of the EOAM devices with PDLC were built on silicon wafers and 26 devices were optically tested. The new chemical mechanical planarization process was implemented for the second and third builds. For optical device testing the phase shift was extracted using a newly developed method for blind phase extraction. The development of a design model for the EOAM system and validating it with the images formed by a real electro-optic adaptive microlens system has provided the knowledge base needed for implementation of adaptive electro-optic lenses for the visible region, and a process which can be used for further improvement of the microsystem. The model parameters can be adjusted for new electro-optic materials that may become available that do not have the limitations of PDLC

Study of the wear of dental composites using an atomic force microscope

This work presents a study of the wear of four dental composites (Concept, XRV, Maxxim, and Belleglass) which are in commercial use. The wear testing was performed using an Atomic Force Microscope (AFM). Several scanning techniques and various cantilevers were attempted. Finally use of a stainless steel cantilever with a tungsten bead attached resulted in quantifiable wear. AFM imaging in contact mode was used for evaluation of the wear tests. Wear rates are reported as volume per 100,000 scans. The AFM measured wear rates rank the tested composites from most to least wear as follows: Concept highest volume of wear XRV Maxxim BelleGlass least volume of wear. Micro-hardness measurements were also conducted

Prediction of cut-off frequency from the maximum slope of a transmittance scan of an ideal edge

This study has empirically shown that the maximum slope of an ideal edge scan in transmittance versus position is an excellent indicator of the cut-off frequency at which a microdensitometer system\u27s modulation transfer function goes to zero. It was found that numerical aperture of collection objective, scanning slit width and alignment, system focus, and sampling interval are parameters which must be carefully chosen and set-up when implementing or using this slope technique to check system performance

OPC and Image Optimization Using Localized Frequency Analysis

A method of assist feature OPC layout is introduced using a frequency model-based approach. Through low-pass spatial frequency filtering of a mask function, the local influence of zero diffraction energy can be determined. By determining isofocal intensity threshold requirements of an imaging process, a mask equalizing function can be designed. This provides the basis for frequency model-based assist feature layout. By choosing assist bar parameters that meet the requirements of the equalizing function, through-pitch focus and dose matching is possible for large two dimensional mask fields. The concepts introduced also lead to additional assist feature options and design flexibility

Exploration of Directed Self Assembly Polymers

Directed Self Assembly (DSA) is an attractive alternative to 193i and multiple patterning. Various polymers were investigated to find the possible structures that can be created with them. Previous research was used to determine the process used. Two surface treatments, a polymer brush and hexamethyldisilazane (HMDS) were used to help the polymers phase separate into their respective structure. The first polymer a polystyrene (PS) block polydimethylsiloxane (PDMS) resulted in de-wetting and film non-uniformity that prevented measurement. The second polymer a PS block polyethylene oxide (PEO) resulted in crystallization if the PEO ratio was too high at 40% mole. When the PEO ratio was low enough at 29% mole and on a PS brush polymer via holes 30 nm in diameter were found using phase imaging on an Atomic Force Microscope (AFM). Repeat samples of the via holes de-wetted from the surface likely due to surface contamination preventing the brush polymer from adhering to the surface

Microelectronic engineering education for emerging frontiers

With the support provided by the National Science Foundation and RIT Provost’s vision for providing flexible curricula, the department of Microelectronic Engineering has instituted new and enhanced program initiatives – (1) offering a semiconductor processing minor for other science and engineering programs promoting access to state-of-the art semiconductor fabrication facilities to students from other programs; (2) crafting a five course elective sequence within the existing curriculum by eliminating legacy material and course consolidation; (3) developing a concentration program in nanotechnology and MEMS; (4) outreach programs for targeting larger and diverse participation in preparing workforce for the nation’s future high tech industry; (5) enhance student learning through co-op and service. The mission is to generate multi faceted work force for the future semiconductor technologies and emerging frontiers spinning off from microelectronics, while simultaneously promoting enrollment particularly from women and minority students

Directed Self Assembly

Current Challenges to manufacturing •Limits of 193i and multiple patterning are approaching •10nm resolution has been demonstrated with multiple patterning •EUV as an alternative is expensive with low throughput Advantages of Directed Self Assembly •Resolution of 20nm and possibly lower •Can be integrated with current patterning techniques •Inexpensive Disadvantages of DSA •Complex patterns can be difficult or impossible to form •Has to be integrated into an existing lithography process •Pattern formation may take large amounts of tim

OPC and image optimization using localized frequency analysis

A method of assist feature OPC layout is introduced using a frequency model-based approach. Through low-pass spatial frequency filtering of a mask function, the local influence of zero diffraction energy can be determined. By determining isofocal intensity threshold requirements of an imaging process, a mask equalizing function can be designed. This provides the basis for frequency model-based assist feature layout. By choosing assist bar parameters that meet the requirements of the equalizing function, through-pitch focus and dose matching is possible for large two dimensional mask fields. The concepts introduced also lead to additional assist feature options and design flexibility. 1