Asymmetric fluid-structure dynamics in nanoscale imprint lithography

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imaging layerof photoresistStep 1: Spin-coat wafer withphotoresistwaferILLUMINATION SOURCEphotomaskStep 2: Expose imaging layerthrough photomask andprojection opticsprojectionopticsStep 3: Develop photoresistFigure 1.1 Optical microlithography process1.2.2 Limitations of Optical LithographyThe International Technology Roadmap for Semiconductors forecasts thevolume manufacture of integrated circuits at the sub-100 nm level within seven toeight years. Since today’s optical lithography steppers are fundamentallydiffraction limited, however, there has been a lot of effort in designing systemsthat minimize the effect of wave diffraction. In order to produce the circuit5
patterns to the desired specifications, the design of the lens system has very tighttolerances, which can cause the equipment costs to quickly escalate.The resolution limit of an optical projection system is governed by theRayleigh formula. This states that the numerical aperture of the lens, thewavelength of light, and the chemical development process determine theminimum line width that a stepper can print [Thompson, Willson, and Bowen1994].LWkλ= [1.1]Nwhere L W is the minimum printable line width (nm), N A is the numerical apertureof the lens in the stepper, k is the factor describing the photoresist developmentprocess, and λ is the wavelength of the exposure source (nm).The minimum printable line width can be reduced by 1) increasing thenumerical aperture, 2) improving the processing of the resists, or 3) decreasingthe wavelength of the source illumination. The design of lens systems has seenan increase in the NA from 0.2 to about 0.73. The proportionality constant k is adimensionless number, which is as low as 0.4 for complex multi-layer resistprocesses along with phase shift masking to 0.8 for standard resist processes.Each generation of microlithography technology has incrementally improved lineresolution by incorporating these hardware and process enhancements along withreducing the wavelength of exposing source.Many of today’s steppers use 248 nm DUV light and there is currently amove to 193 nm argon fluoride excimer laser systems with 157 nm systems indevelopment. Exposure systems with even shorter wavelengths such as x-ray (λ≈ 1 nm) and extreme ultraviolet (EUV or soft x-ray, λ ≈ 13 nm) are beingA6
Page 3 and 4: Asymmetric Fluid-StructureDynamics
Page 5 and 6: AcknowledgementsFirst of all, I wou
Page 7 and 8: Table of ContentsList of Tables ...
Page 9 and 10: 6.2.3 Control Software ............
Page 11 and 12: List of FiguresFigure 1.1 Optical m
Page 13 and 14: Figure 6.9 Force due to fluid press
Page 15 and 16: The exponential escalation in the c
Page 17: 1.2.1 Optical Lithography Process O
Page 21 and 22: 1.3 STEP AND FLASH IMPRINT LITHOGRA
Page 23 and 24: transferlayerwaferStep 1: Spin-coat
Page 25 and 26: the etch barrier fluid has an infin
Page 27 and 28: Researchers at the University of Te
Page 29 and 30: stage development. Design requireme
Page 31 and 32: minimum and maximum base layer thic
Page 33 and 34: square plate with fluid completely
Page 35 and 36: 7. The fluid is assumed incompressi
Page 37 and 38: ⎛ ∂ ⎞⎜τdz ⎟dxdy⎝+ τ
Page 39 and 40: where V 1 and V 2 correspond to U 1
Page 41 and 42: ddx⎛⎜h⎝3dp ⎞ ∂h⎟ = 12µ
Page 43 and 44: dhdtLzhθh αh βxx αx = 0 x βFig
Page 45 and 46: C2hhtanθ2 21= αxαxβxαxβ( ) (
Page 47 and 48: ⎛⎜ hD⎜⎝6C ⎞1tanθ⎟24µh
Page 49 and 50: at the plate edges. Freeland obtain
Page 51 and 52: For the case of 10 psi of pressure,
Page 53 and 54: are the same as the width of the tr
Page 55 and 56: orientation stages relative to the
Page 57 and 58: Wafer ChuckAir SolenoidMounting Pla
Page 59 and 60: The one degree-of-freedom template
Page 61 and 62: Figure 3.7 Initial and final desire
Page 63 and 64: 7645321Figure 3.8 Active stage prot
Page 65 and 66: Chapter 4: Real-Time Gap Sensing Vi
Page 67 and 68: R( λ)( 4πnd/ λ)2 2 −2αd−αd
Page 69 and 70:
Rate Monitoring and is adapted for
Page 71 and 72:
10090807060PSD504030201000 500 1000
Page 73 and 74:
the multi-imprint and active stage
Page 75 and 76:
5.2.2 Composite Stiffness and Dampi
Page 77 and 78:
( )2πR−1.5clamping length of 1.5
Page 79 and 80:
65actuator height, micron432100 0.1
Page 81 and 82:
time marching is required to minimi
Page 83 and 84:
5.4 SQUEEZE FILM DYNAMICS OF INCLIN
Page 85 and 86:
force, lb504540353025201510500 0.05
Page 87 and 88:
improve upon these results by tunin
Page 89 and 90:
Again, Figure 5.12 shows that a bas
Page 91 and 92:
optically flat quartz plate coated
Page 93 and 94:
optic probe was illuminated with a
Page 95 and 96:
Figure 6.3 Screenshot of control so
Page 97 and 98:
6.3 EXPERIMENTAL PROCEDUREExperimen
Page 99 and 100:
film thickness, nm40003800360034003
Page 101 and 102:
Figure 6.6 shows that the force due
Page 103 and 104:
similar. In Figures 6.7 and 6.8, th
Page 105 and 106:
500045004000film thickness, nm35003
Page 107 and 108:
Figure 6.13 shows the force-time pl
Page 109 and 110:
⎛ n ⎞in the FFT that is not ind
Page 111 and 112:
when measuring thin layers in the r
Page 113 and 114:
is a major milestone. The next step
Page 115 and 116:
7.2.4 Control schemeThe ultimate go
Page 117 and 118:
Assuming the liquid perfectly wets
Page 119 and 120:
ase h (for a semi-circular notch,h
Page 121 and 122:
Chou, S. Y., P .R. Krauss, and P. J
Page 123 and 124:
Tripp, J. H. 1983. Surface roughnes
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Asymmetric fluid-structure dynamics in nanoscale imprint lithography

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