Optimal window glass assemblies have been developed for three use cases, when the average outside temperature is greater or less than the target indoor temperature. These assemblies have 2× better insulation than a standard double glazed window. They were developed by identifying insulation strategies for each of the 4 energy bands that transfer heat through windows. The insulation strategies were identified through analytical models for each energy band. The strategies were then applied to glasses in the DOE International Glass Data Base and evaluated using the industry standard modelling programs. These evaluations provided a systematic method to developed optimal glass assemblies.
Oblique angle metal deposition has been combined with high aspect ratio imprinted structures to create wire grid
polarizers (WGP’s) for use as polarization recyclers in liquid crystal displays. The process of oblique deposition
was simulated to determine optimal feature profile and deposition geometry. The optical results for the oblique
deposition WGP show contrast comparable to a conventionally etched WGP. The next steps to the fabrication of
meter sized WGP are proposed.
Oblique angle metal deposition has been combined with high aspect ratio imprinted structures to create wire grid polarizers (WGP’s) for use as polarization recyclers in liquid crystal displays. The optical results for the oblique deposition WGP show contrast comparable to a conventionally etched WGP. In addition, the WGP showed improved spectral and spatial uniformity as compared to a multilayer reflective polarizer. The next steps to the fabrication of meter sized WGP are proposed.
The Cost of ownership (COO) due to the mold can be minimized by first creating the smallest possible original. The cost of this original can be reduced by using the lowest possible resolution pattern generator. If the pattern is regular, then analog pattern generation such as interferometry can be used. The small original is then copied to cover the area by either Step and Repeat or Tiling. Finally multiple working copies are made in a tooling tree for production imprint. The cost and life of the working copies depends on the imprint technology.
The challenge in manufacturing disposable bio micro-fluidic devices centers on making complex structures
with controlled wetting and adhesion characteristics that can be used with fluorescence detection at a very
low cost of < $1 a part. We will report on a new low fluorescence UV curable material that can be
patterned in the Contact Liquid Photolithographic Polymerization (CLiPP) process developed at U
Today, there are a number of successful commercial applications that utilize roll to roll processing and almost all
involve optics; unpatterned film, patterned film, and devices on film. The largest applications today are in
holograms, and brightness enhancement film (BEF) for LCD. Solar cells are rapidly growing. These are mostly
made in large captive facilities with their own proprietary equipment, materials and pattern generation capability.
World wide roll to roll volume is > 100M meters2 year-1, and generates sales of > $5B. The vast majority of the
sales are in BEF film by 3M.
High resolution patterning of LED's has shown the potential to significantly increase the light output. There are 3
different imprint strategies being proposed to manufacture these devices. These imprint solutions and all the support
equipment for cleaning, coating, and etching form an imprint cell. This paper will compare the imprint cell and process
Imprint is probably the only patterning technology that can deliver sub 100 nm features at a low enough cost to be of
interest to the LED manufacturers. Patterning fine features on LED wafers must be able to deal with rough, non flat
wafers. The competing imprint solutions rely on either;
1) flexing the wafer or
2) flexing the template or
3) making the surface of the template compliant,
The published data on wafer non-flatness, and the compliance of the different solutions will be compared.
Process solutions are still needed to eliminate residual non-conformality. The overall margin of the different process
solutions will be compared, multilayer processes can tolerate 2.5 x larger residual layer variation than single layer
The literature on high brightness LED's shows that patterning the top surface of LED's with photonic crystals is being used to create the most intense LED light sources. The best example is that you can now buy projection displays that are illuminated by LED's with Photonic Crystals.
The experimental and model data, reviewed in this article, shows that patterning delivers value through improved beam shaping and light extraction using carefully optimized photonic crystals. The data also suggests that in the future, patterning in combination with sub micron device layers and strategically placed mirrors can produce extraction efficiencies of greater than 80%. In addition, patterning can improve current spreading and reduce epitaxy defects. The long term goal is to develop a LED that can be used with minimal additional packaging to focus the light or extract heat.
The solution to low cost patterning for Photonic Crystals 100 nm features is to use imprint. The imprint patterning process is implemented in a module that consists of a clean and coat tool, an imprint tool and an etch tool. Cleaning is essential because imprint is a contact technology and particles will lead to process defects and mold damage. There are 2 companies that are developing production tools for LED applications; Molecular Imprints (MII) and Obducat. There are 2 companies that are supporting research tools, and expect to develop production systems in response to customer order, EV Group and Nanonex. The principal difference between imprint suppliers are the different strategies used to conform the mold to the substrate, and the state of system development. To date MII has published the most complete process performance data on an automated production tool. The cost of patterning is less than 0.5 cent per device.
First the value of increased LED output will be described, followed by a discussion of the different patterning solutions for improving output, then the different solutions for creating the patterning will be described and finally the costs are estimated.
The Step and Flash Imprint Lithography (S-FILTM) process is a step and repeat nano-imprint lithography (NIL) technique based on UV curable low viscosity liquids.1,2,3Investigation by this group and others has shown that the resolution of replication by imprint lithography is limited only by the size of the structures that can be created on the template (mold). S-FIL uses field-to-field drop dispensing of UV curable liquids for step and repeat patterning. This approach allows for micro and nano-fabrication of devices with widely varying pattern densities and complicated structures. Wire grid polarizers and micro lenses are two examples for optical components that can be formed using SFIL technology. Step and Flash Imprint Lithography Reverse (S-FIL/R) tone has been used to form resist patterns for a number of different device types 1,4,6. The authors have employed S-FIL/R and dry develop techniques to form resist patterns with 100 nm period useful for the fabrication of wire grid polarizers. S-FIL/R has a number of advantages over interference lithography techniques for the fabrication of sub 200 nm period grating structures including but no limited to pattern repeatability, vibration insensitivity, high aspect ratio feature formation, greater extendibility and high resolution. The authors have devised imprint and dry etching processes for resist and substrate patterning to form Al based wire grid polarizers with 100 nm pitch. The fabrication processes and resulting devises will be described. While S-FIL is useful for in the formation of resist patterned wafers, it is also capable of forming devices by functional material patterning. Polymer micro lenses are a good examples of functional material devices useful for a number of
applications including CMOS and CCD cameras. The fact that lens geometry is defined by the template and requires no post imprint processing provides a strong advantage over current lens formation approaches. Recent results and the state of current micro lens fabrication by S-FIL is described.
The Step and Flash Imprint Lithography (S-FILTM) process is a step and repeat nano-imprint lithography (NIL) technique based on UV curable low viscosity liquids. Generally nano-imprint lithography (NIL) is a negative acting process which makes an exact replica of the imprint mold and is subsequently dry developed to reveal the underlying substrate material. The authors have demonstrated a novel imprint process, which reverses the tone of the imprint and enables dry develop on nonflat wafers with good critical dimension control and resist layer thickness. This positive acting NIL process termed SFIL/RTM (reverse tone S-FIL), enables nano-imprinting over intrinsic substrate topology of the type commonly found on single side polished substrates. This paper describes the SFIL/R process and the results of pattern transfer on single side polished silicon wafers.
The Step and Flash Imprint Lithography (S-FILTM) process is a step and repeat nano-replication technique based on UV
curable low viscosity liquids. Molecular Imprints, Inc. (MII) develops commercial tools that practice the S-FIL process.
This talk will present the imprint materials that have been developed to specifically address the issue of process life and
The S-FIL process involves field-to-field dispensing of low viscosity (<5 cps) UV cross-linkable monomer mixtures.
The low viscosity liquid leads to important advantages that include:
• Insensitivity to pattern density variations
• Improved template life due to a lubricated template-wafer interface avoids “hard contact” between template and
• Possibility for lubricated (in-situ) high-resolution alignment corrections prior to UV exposure
The materials that are optimal for use in the S-FIL process need to possess optimal wetting characteristics, low
evaporation, no phase separation, excellent polymer mechanical properties to avoid cohesive failure in the cured material,
low adhesion to the template, and high adhesion to the underlying substrate.
Over 300 formulations of acrylate based monomer mixtures were developed and studied. The imprint materials were
deemed satisfactory based on the process of surviving imprinting more than 1500 imprints without the imprints
developing systematic or repeating defects. For the purpose of these process studies, printing of sub-100 nm pillars and
contacts is used since they represent the two extreme cases of patterning challenge: pillars are most likely to lead to
cohesive failure in the material; and contacts are most likely to lead to mechanical failure of the template structures.
Step and FlashTM Imprint Lithography (S-FILTM) process is a step and repeat nano-replication technique based
on UV curable low viscosity liquids. Molecular Imprints, Inc. (MII) develops commercial tools that practice
the S-FIL process. The current status of the S-FIL tool and process technology is presented in this paper. The
specific topics that are covered include:
• Residual layer control
• Etch process development
• Patterning of lines, contacts and posts
• CD control
• Defect and process life
• Alignment and magnification control
Molecular Imprints, Inc. (MII) has developed the ImprioTM 100, which is the first commercial step and repeat imprint lithography system with field-to-field alignment. This system is designed to implement the UV curable nano-replication capability of the Step and FlashTM Imprint Lithography (S-FILTM) process. To-date, the Imprio 100 system has demonstrated: 1) Full 200 mm wafer coverage with lithographically useful patterning; 2) Full wafer residual thickness control to enable practical etching (thickness variation < 50 nm, 3 sigma); 3) Field edge control compatible with 50 um kerf regions. 4) Multi-day CD uniformity measured on an analytical SEM < 2 nm, 3 sigma with no process adjustments; 5) Etch pattern transfer including break-through etch of residual material, followed by a bi-layer etch through thick planarization layers; 6) Initial level-to-level alignment target acquisition with accuracy of better than 100 nm. 7) Low air borne particle counts in tool microenvironment consistent with Class 0.1 while imprinting.
Accurate technology projections are the key to any attempt to identify future product needs and technical
road blocks. For coat and develop, the goal is to be able to project resist thickness and develop uniformity
control requirements as device geometries shrink. In addition, it would be desirable to project the
temperature and exhaust control required to achieve a specific resist thickness control. This paper will
describe a new procedure for technology projections at coat and develop. It is based on a hierarchical
analysis of variance combined with simple physical models of resist properties.
Traditionally, people" have used an experimental approach to identify key variables. In these experimental
approaches, the process is treated as a "black box" to be investigated using statistically designed experiments.
These data tell the process engineer a lot about the current process. They do not help with technology
To project the future, some sort of model is needed. The model described here uses a "top down" approach
that starts from the desired line width control expressed in statistical terms.