Asymmetric fluid-structure dynamics in nanoscale imprint lithography

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template and the wafer. As a part of the research for this thesis, an active stagetest bed is being developed. The motion capability of the active stage system isbased on the ideal Revolute Prismatic Ball (RPB) stage. The RPB platform hasbeen thoroughly analyzed [Johnson 1999].The systems that make up this test bed are 1) a wafer stage assembly, 2)template orientation stages 3) a micro-fluidic etch barrier dispensing system, 4) ahigh-resolution actuation system, 5) a gap sensing/orientation measurementsystem, and 6) a force measurement system. Each system must be designed orpurchased as a modular component so that design modifications can beimplemented or customized within reasonable costs and time constraints. Thefollowing discussion will provide some insight into the design requirements of thesubsystems relevant to this research. The details of the gap sensing theory andimplementation are given in chapter 4. A complete discussion of the entire activestage project is beyond the scope of this thesis, as the active stage test bed iscurrently in its infancy stage.3.2.1 Wafer Stage AssemblyThe wafer stage must bring the wafer substrate to within the motion rangeof the DC Mike motor and hold the wafer in place during imprinting. The waferchuck must hold the wafer with minimal distortion by providing a uniformpressure across the backside of the wafer. Current wafer manufacturers providewafers with low frequency height variations across their diameter. Using a flatvacuum wafer chuck with uniform pressure across the supporting surface canminimize these oscillations. Figure 3.1 shows the current embodiment of thewafer stage assembly. Air solenoids lift the wafer to within the motion range ofthe actuation system.43
Wafer ChuckAir SolenoidMounting PlateFigure 3.1 Wafer stage assembly3.2.2 Template Orientation StagesThe motion requirement for the template orientation stage is that thecenter of rotation of the stage is at the geometric center of the surface of thetemplate (see Figure 3.2). The template orientation stages from the multi-imprintstepper fulfill this requirement by using the four-bar linkage flexure mechanismshown in Figure 3.3. Each stage provides a decoupled motion capability aboutone axis, a rotation about the x axis (α) and a rotation about the y axis (β).Joint 1Joint 4Joint 2Joint 3Template-WaferInterfaceFigure 3.2 Motion requirement for template orientation 4CTemplate4 Taken from Choi et al 2000.44
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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 and 18: 1.2.1 Optical Lithography Process O
Page 19 and 20: patterns to the desired specificati
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: orientation stages relative to the
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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