Data compression is an effective method for saving storage space and ission bandwidth. The compression scheme must be lossless for the layout
t be changed. The compression algorithm has to adapt to the changes in cture to make the compression ratio as big as possible. Meanwhile, the plementation of the compression and decompression must be minimizing memory n processing complexity and real-time ability hardware implem
transm figure can’
the data stru im
and power. The trade-off betwee
entation need to be further research. Recently a novel lossless compress technique called Context-Copy-Combinatorial-Code (C4). The C4 is designed dedicated for pixel format layout data. Although it can’t use in hybrid format data, but its algorithm is worth to investigate for our further research in data format chosen.
Appendix J Zone-plate Array Lithography
. Introduction to Zone-Plate-Array Lithography 1Figure 15 Schematic of ZPAL system[18]
In Zone-plate-Array Lithography system,a zone-plate array is used to create an array of tightly focused spots on the photoresist-coated surface of a substrate. By modulating the light intensity incident on each zone plate by means of an upstream spatial light modulator (SLM) while scanning the substrate, one can write patterns of arbitrary geometry in
An array of Fresnel zone plates focuses incident radiation into an array of spots on a
ted by the following equation:
a dot matrix fashion.[18][19]
substrate. The spot size is approximately equal to the outer zone width of the zone plate. By means of micromechanics, incident light is split into multiple beamlets and can be switched on and off. The beamlet turn on is reflected to the zone plate and simultaneously scanning the substrate in a raster route.[20]
The throughput of ZPAL system can be evalua
( ) ( )
2
total 2
WaferDiameter
T ∝ OZW # ofZonePlates ,
where T total is the time in seconds and the OZW is the outer zone width. The throughput in terms of wafers per hour is simply
total
Wafers 3600
ing the minimum feature size (i.e. OZW) by a factor of 2 decreases the throughput by a factor of 4. If the number of Zone Plates is increased, the throughout of wafer becomes very large.
2nm or below, lig
Hour = T , and decreas
Currently, ZPAL utilizes 193nm wavelength light, and achieve a minimum feature size of . To achieve the resolution of 3 ht wavelength should be reduced below 193nm, even below 157nm. Here we evaluate the
capability of ZPAL with EUV source. We calculate the resolution from the resolution equation: Wmin 1k
NA
= ×
λ
, with 0.8 k1 and 0.7 NA, and 13.5nmwavelength. About 15nm resolution is obtained.
2. SLM
Figure 16 Manufacturing process of zone-plate
As figure shows, SLM consists of micro-mirror array in the path of the radiation.
With accurate alignment and tilting angle adjustment, each mirror will be responsible for the illumination of an individual zone plate.
3. Fabrication of UV Zone Plates
Figure 17 Manufacturing process of zone-plate
The main steps of the process are the following:
1. Defining the areas in which the zone plates are going to be placed.
2. Surrounding these areas with a Cr layer of the thickness calculated in the last section.
3. E-beam write
ired s the actual zones inside the clear circles.
Reactive ion etch the wafer to provide the des π phase shift.[21]
Appendix K Optical Maskless Lithography (OML)
ASML is one of the three leaders of lithographic equipment suppliers, and they proposed their optical ML2 solutions -- OML. OML system
conventional optical lithographic scanne a
is different from technology
replaces the m ×2048
or lift to introduce intensity loss or ph
r in the m sk stage. OML ask by a spatial light modulator (SLM), which consists of 512 adjustable micro-mirrors. Each micro-mirror can be tilt
ase shift of the incident light. Hence, desired patterns can be generated by the SLM, and then demagnified and imaged onto the wafer. Currently, OML aimed at 65nm and 45nm node and utilize 193nm wavelength DUV. Throughput evaluated is about 5 300mm per hour.[22][23][24]
Figure 18 Schematic of OML system[22]
Appendix L Near-field Lithography
Under the near-field conditions, the local electromagnetic fields that exist lectric and metallic nanostructures can be used to circumvent the diffraction limit. Near-field lithography utilize some material and / or structure as a
aveguide and place the waveguide extremely near to the resist, even contact with it,
le when the excitation occurs at the resonance frequ
around die w
to write high resolution patterns.
A new approach that can potentially produce sub-wavelength structures uses broad beam illumination of standard resist with visible light. This method is based on the plasmon resonance occurring in nanoscale metallic structures. When a metal nanoparticle is placed in an optical field, it exhibits a collective electron motion known as the surface plasmon oscillation. This can result in strongly enhanced electrical fields near the partic
ency.[25]
Figure 19 Near-Field Lithography[26]
As Figure 19 shown, illumination of metal nanoparticles at plasmon resonance produces a strongly enhanced dipole field near the particle. This enhanced field can be used to locally expose a thin layer of resist. In order to obtain intensity enhancement directly below the particle, the incoming light should be polarized approximately normal to the resist layer (p-polarization), implying the need for
glancing incidence exposure. W hancement
occurring around metal nanoparticles when they are excited at the surface plasmon reson
e have shown that the local field en
ance frequency can be used to print nanoscale features in thin resist layers.
Feature sizes below λ/10 can be generated using visible illumination and standard g-line photoresist.[26]
Appendix M Dip-pen Lithography
Dip-Pen Nanolithography (DPN) is a scanning probe nanopatterning technique in which an AFM tip is used to deliver molecules to a surface via a solvent meniscus, which naturally forms in the ambient atmosphere.
As the AFM tip approaches the substrate, a water meniscus forms between them. The molecules transport and anchor themselves to the substrate via
hen alkanethiols are patterned on a which the thiol headgroups form relatively stron
5
One of the most important attributes of DPN is that, because the same device is chemisorptions or electrostatic interactions. W
gold substrate, a monolayer is formed in
g bonds to the gold and the alkane chains extend roughly perpendicular to surface (Figure 20).
Creating nanostructures using DPN is a single step process which does not require the use of resists. Using a conventional atomic force microscope (AFM) it is possible to achieve ultra-high resolution features with linewidths as small as 10-1 nm with ~ 5 nm spatial resolution. For nanotechnological applications, it is not only important to pattern molecules in high resolution, but also to functionalize surfaces with patterns of two or more components.
Figure 20 Dip-Pen Nanolithography[27]
used to image and write a pattern, patterns of multiple molecular inks can be formed or aligned on the same substrate. With the aid of software created in-house (which has been commercialized through NanoInk), we have devised a nanolithographic tool which is ink-general and allows for simple registration of inks. Also, the contamination which could result from typical lithographic techniques (such as photolithography), is avoided.[27]
Appendix N Focused Ion Beam Lithography
IBL is similar to EBL in applications, feature sizes and the fact that it is a serial approach, but uses a beam of ions instead of electrons (Figure21). A fundamental difference is that ions are charged atomic that can interact physically and chemically with, and settle into, the exposed material ,and the particles of which are many
ore massive than electrons. This addition of material offers rather than just creating structures
e is determined by the lateral dose distribution of the ion beam, which varies with depth in the resist.
orders of magnitude m
the possibility of building up structures destructively.[28]
Ion Beam Lithography using MeV protons is a technique which is able to produce 3D microstructures in positive resists such as PMMA as well as in negative resists such as SU-8. An advantage of IBL is that no mask is needed to produce structures with high aspect ratios and sub-micrometer detail in the lateral direction.
There are two basic features of the IBL setup: First is the implementation of a faster scanning system spherically designed for high resolution IBL. Second, the smallest feature size attainabl
[29]
Figure 21 Schematic of focused ion beam lithography[30]
Appendix O Nano-imprint Lithography
Nanoimprint is an emerging lithographic technology that promises high-throughput patterning of nanostructures. Based on the mechanical embossing principle, nanoimprint technique can achieve pattern resolutions beyond the limitations set by the light diffractions or beam scatterings in other conventional techniques. There are three major ways to achieve the process:
1. Nano-Imprint Lithography
Imprint lithography has two steps: imprint and pattern transfer. In the imprint, a mold with nanostructures on its surface is pressed into a thin resist cast on a substrate.
The resist, a thermal plastic, is deformed readily by the mold when heated above its glass transition temperature (due to a low viscosity). After the resist is cooled below its glass transition temperature, the mold is removed (Figure 22). In the pattern transfer, an anisotropic etching process, such as reactive ion etching, is used to
remove the ess contrast
attern created in the imprint into the entire resist.[31]
residual resist in the compressed area, transferring the thickn p
Figure 22 Nano-Imprint Lithography [31]
2. Step and Flash Imprinting Lithography
An organic thermoset planarizing/transfer layer was coated on a silicon wafer nd then cured. A thin layer of a silicon-containing thermoplastic was spin coated on t ysilicon on silicon template was brought into contact with
a
the ransfer layer. An etched pol
the coated substrate. This “sandwich” structure was then placed in a press and heated to 150 °C under pressure for 15 minutes (Figure 23). An advantage to this process is that one needs only to generate low aspect ratio features. These features can then be transferred through the transfer layer via an anisotropic O2 RIE etching process analogous to that used in bilayer lithography to generate high aspect ratio, high-resolution images.[32]
Figure 23 Step and Flash Imprinting Lithography[32]
3. Laser Assisted Direct Imprint
In ‘laser-assisted direct imprint’ (LADI)—a single excimer laser pulse melts a thin surface layer of silicon, and a mould is embossed into the resulting liquid layer(Figure 24). A variety of structures with resolution better than 10 nm have been imprinted into silicon using LADI, and the embossing time is less than 250 ns. The high resolution and speed of LADI, which we attribute to molten silicon’s low viscosity (one-third that of water), could open up a variety of applications and be extended to other materials and processing techniques. [33]
Figure 24 Laser-assisted direct imprint[33]
5. Reference
[1] SEMATECH Maskless Workshop, Jan. 2005. Available at
http://www.sematech.org/resources/litho/meetings/emerging/20050117/
[2] B.J. Kampherbeek, “MAPPER Technology Developments,” Maskless Workshop, January 17-19 2005
[3] Moonen, D., L.H.A. Leunissen, P.W.H. de Jager, P. Kruit, A.J. Bleeker, K.D. v.d. Mast, “Design of an Electron Projection System with Slider
Lenses and Multiple Beams,” in Proceedings of SPIE 2002, 5-7 march
2002.[4] T. Haraguchi, T. Sakazaki, S. Hamaguchi, and H. Yasuda,
“Devel ltielectron beam
lithography system,” Journal of Vacuum Sciences and Technology B 20
(6), Nov/ Dec, 2002[5] Yasuda Hiroshi, “A proposal for an MCC (Multi-Column Cell with
Lotus Root lens) system to be used as a mask making e-beam tool,”
Proceedings of the SPIE, Volume 5567, pp. 911-921, 2004.
Yamada, ADVANTEST Technology Developments, Maskless rkshop, January 17-19 2005
ojection lithography,” US Patent
[9]
[11] r, Projection maskless lithography, Proceedings of
[12]
opment of electromagnetic lenses for mu
[6] A.
Wo
[7] Phillip Ware, “Removing The Mask,” oe magazine pp. 26-27, march 2002.
[8] Marian Mankos, Harald F. Hess, David L. Adler, and Kirk J. Bertsche,
“Maskless reflection electron beam pr
Issued on March 22, 2005N. William Parker, A high throughput NGL electron beam direct-write
lithography system, Proceedings of SPIE, Volume 3997, pp. 713-720,
2000[10] T.S. Ravi, MultiBeam Systems Technology Developments, Maskless Workshop, January 17-19 2005
Christoph Brandstätte
the SPIE, Volume 5374, pp. 601-609, 2004.
C. Brandstätter, Leica Technology Developments, Maskless Workshop, January 17-19 2005.
[13] Juergen Gramss, Hans Eichhorn, Melchior Lempke, Renate Jaritz, Volker Neick, Dirk Beyer, Bertram Buerger, Ulrich Baetz, Klaus Kunze,
, Microelectronic Engineering 83 (2006)
direct-write maskless
[18] ith., “Experimental
[19]
ith Zone-Plate-Array Lithography by
and Nikola Belic, “Data prep: the bottleneck of future applications?”, Proc. SPIE 6281, 2006
[14] Sven-Hendrik Voss and Maati Talmi ,”FPGA based high-speed system
solutions for innovative maskless lithography systems”,
Proc. SPIE 6283, 2006[15] Sven-Hendrik Voss a,*, Maati Talmi a, Juergen Saniter a, Juergen Eindorf a, Alexander Reisig a, Joachim Heinitz b, Ernst Haugeneder,
“High-speed data storage and processing for projection mask-less lithography systems”
[16] Vito Dai and Avideh Zakhor ,”Lossless layout compression for maskless
lithography systems”,
Proc. SPIE 3997, 2000[17] Hsin-I Liu, Vito Dai, Avideh Zakhor, and Borivoje Nikolic, “Reduced
complexity compression algorithms for
lithography systems”, Proc. SPIE 6151, 2006
Rajesh Menon, Dario Gil, and Henry I. Sm
characterization of focusing by high-numerical-aperture zone plates”
Journal of the Optical Society of America A, vol. 23, Issue 3, pp.
567-571, 2006.
Maskless Parallel Patterning w
Dario Gil, Master’s thesis, Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, June 2000.
[20] Rajesh Menon, Amil Patel, David Chao, Michael Walsh, and H. I. Smith,
“Zone-Plate-Array Lithography (ZPAL): Optical Maskless Lithography for Cost-Effective Patterning,” Proceedings of the SPIE, Volume 5751,
pp. 330-339, 2005[21] Dario Gil, “Maskless Parallel Patterning with Zone-Plate-Array
Lithography,” June 2000.
[22] Timothy O’Neil, Arno Bleeker, and Kars Troost, “Optical Maskless
Lithography (OML) Project Status,” Maskless Workshop, January
17-19 2005.[23] Tor Sandstrom, Arno Bleeker, Jason D. Hintersteiner, Kars Troost, Jorge Freyer, and Karel van der Mast, “OML: optical maskless lithography
for economic design prototyping and small-volume production,”
Proceedings of SPIE -- Volume 5377, pp. 777-787, May 2004.
[25] . Kik, Stefan A. Maier, and Harry A. Atwater, “Plasmon
[26]
://kik.creol.ucf.edu/index.htm
[24] Hans Martinsson, et al., “Current status of optical maskless
lithography,”
Journal of Microlithography, Microfabrication, and Microsystems, Volume 4, Issue 1, pp. 11003, 2005.Pieter G
Printing-A New Approach to Near-Field Lithography” Mat. Res. Soc.
Symp. Proc. 705, Y3.6, 2002.
Homepage: NanoPhotonics Characterization Lab. of University Central Florida － at http
Nanolithography,” Science, 1999, 283, 661-663.
[28] Paul Holister, Cristina Román Vas, Tim Harper, “Lithography
Technology White Paper,” Cintífica, LTD., October 2003
[29] J.A. van Kan, J.L. Sanchez, B. Xu, T. Osipowicz, F. Watt,
“Micromachining using focused high energy ion beams: Deep Ion,”
Nucl. Instr. and Meth. in Phys. Res. B 148 (1999) 1085-1089 John Melngailis, “Focused ion beam technology and applic
Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, March 1987, Volume 5, Issue 2, pp. 469-495 Stephen Y. Chou, Peter R. Krauss, Wei Zhang, Li
Zhuang, “Sub-10 nm imprint lithography and applications,” J. Vac. Sci.
Technol. B 15.6., Nov/Dec 1997 M. Colburn, S. Johnson, M. S
Wedlake, T. Michaelson, S.V. Sreenivasan, J. Ekerdt, and C. G. Willson,
“Step and Flash Imprint Lithography:A New Approach to High-Resolution Patterning,” Proc. SPIE, 1999
[33] Stephen Y. Chou, Chris Keimel and Jian Gu, “Ultrafast and direct
imprint of nanostructures in silicon,” 20 JUNE 2002, NA
417