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A low-speed experimental investigation of the effect of a sandpaper type of roughness on boundary-layer transition

Description: From Summary: "An investigation was made in the Langley low-turbulence pressure tunnel to determine the effect of size and location of a sandpaper type of roughness on the Reynolds number for transition. Transition was observed by means of a hot-wire anemometer located at various chordwise stations for each position of the roughness. These observations indicated that when the roughness is sufficiently submerged in the boundary layer to provide a substantially linear variation of boundary-layer velocity with distance from the surface up to the top of the roughness, turbulent "spots" begin to appear immediately behind the roughness when the Reynolds number based on the velocity at the top of the roughness height exceeds a value of approximately 600. At Reynolds numbers even slightly below the critical value (value for transition), the sandpaper type of roughness introduced no measurable disturbances into the laminar layer downstream of the roughness. The extent of the roughness area does not appear to have an important effect on the critical value of the roughness Reynolds number."
Date: August 15, 1956
Creator: von Doenhoff, Albert E. & Horton, Elmer A.
Partner: UNT Libraries Government Documents Department

A low-speed experimental investigation of the effect of a sandpaper type of roughness on boundary-layer transition

Description: Report presenting an investigation in the low-turbulence pressure tunnel to determine the effect of size and location of a sandpaper type of roughness on the Reynolds number for transition. Transition was observed by means of a hot-wire anemometer at various chordwise stations for each position of roughness.
Date: October 1956
Creator: von Doenhoff, Albert E. & Horton, Elmer A.
Partner: UNT Libraries Government Documents Department

Boundary-layer transition at Mach 3.12 with and without single roughness elements

Description: Report presenting temperatures on the external surface of a straight hollow cylinder aligned parallel to the air stream. Results regarding the recovery-factor distribution without roughness, transition without roughness, transition caused by roughness, and analysis of roughness results are provided.
Date: December 1954
Creator: Brinich, Paul F.
Partner: UNT Libraries Government Documents Department

Recovery temperatures and heat transfer near two-dimensional roughness elements at Mach 3.1

Description: Report presenting an investigation to determine the effect of single and multiple two-dimensional roughness elements on the temperature distribution, pressure distribution, and heat transfer at Mach 3.1. Results regarding recovery temperatures and heat transfer are provided.
Date: February 1958
Creator: Brinich, Paul F.
Partner: UNT Libraries Government Documents Department

Effects of surface roughness and extreme cooling on boundary-layer transition for 15 degrees cone-cylinder in free flight at Mach numbers to 7.6

Description: Report presenting an investigation of three cone-cylinder bodies to obtain boundary-layer-transition data at very low ratios of wall to local stream temperature. Surface finishes at several levels of roughness height were tested. Results regarding the smooth body and rough bodies are provided.
Date: March 5, 1958
Creator: Rabb, Leonard & Krasnican, Milan J.
Partner: UNT Libraries Government Documents Department

Experimental investigation of the problem of surface roughness

Description: Based on the universal laws of turbulent velocity distribution at rough and smooth walls, there is in the present work presented a method that allows surface roughness tests and in particular, measurements on the roughness of ship surfaces to be carried out in a much simpler manner. The types of roughness investigated were in the form of flat, rough plates installed in a square-section rectangular channel, the other three walls always being smooth. Twenty-one plates of various roughness were investigated, the roughness elements being the following: spheres of diameter 0.41 and 0.21, respectively, spherical segments, cones, and "short" and "long" angles.
Date: April 1937
Creator: Schlichting, H.
Partner: UNT Libraries Government Documents Department

The effect of surface roughness on the performance of a 23 degree conical diffuser at subsonic Mach numbers

Description: Report of an investigation to determine the effect of surface roughness on the performance of a 23 degree conical diffusers with 2:1 ratio of exit to inlet area and a constant-area tail pipe. Information about the pressure survey results, including total-pressure-loss coefficient, diffuser effectiveness, and boundary-layer profiles is provided.
Date: January 16, 1952
Creator: Persh, Jerome
Partner: UNT Libraries Government Documents Department

Investigation of distributed surface roughness on a body of revolution at a Mach number of 1.61

Description: Report presenting an investigation of the effects of distributed surface roughness, consisting of lathe-tool marks, on the skin-friction drag of a body of revolution at Mach number 1.61. Tests were conducted on ogive-cylinders at zero angle of attack over a range of roughness and Reynolds number. The results indicate that the effects of surface roughness are generally similar to those found at subsonic speeds.
Date: June 1954
Creator: Czarnecki, K. R.; Robinson, Ross B. & Hilton, John H., Jr.
Partner: UNT Libraries Government Documents Department

Effects of fabrication-type roughness on turbulent skin friction at supersonic speeds

Description: Report presenting an investigation of the effects of fabrication-type surface roughness on turbulent skin-friction drag at supersonic speeds. It was found that fabrication of the thin-skin constructions could be done sufficiently well in practice so as to cause no increase in drag over the smooth body; however, the juncture-type roughnesses produced significant increases in drag as compared with the smooth body. Results indicated that increasing the unit Reynolds number has a detrimental effect and increased the Mach number has a powerful alleviating effect on drag due to surface roughness.
Date: July 1958
Creator: Czarnecki, K. R.; Sevier, John R., Jr. & Carmel, Melvin M.
Partner: UNT Libraries Government Documents Department

Investigation of effects of distributed surface roughness on a turbulent boundary layer over a body of revolution at a Mach number of 2.01

Description: Report presenting an investigation of the effects of distributed surface roughness, consisting of lathe-tool marks, on the skin friction of a turbulent boundary layer over a body of revolution at Mach number 2.01. The investigation was made on three ogive-cylinders at zero angle of attack over a surface-roughness range from 23 to 480 microinches root mean square. Results indicated that the effects of distributed surface roughness on a turbulent boundary layer at Mach number 2.01 are generally similar to those found at Mach number 1.61 and at subsonic speeds.
Date: February 1958
Creator: Sevier, John R., Jr. & Czarnecki, K. R.
Partner: UNT Libraries Government Documents Department

Assessing out-of-band flare effects at the wafer level for EUV lithography

Description: To accurately estimate the flare contribution from the out-of-band (OOB), the integration of a DUV source into the SEMATECH Berkeley 0.3-NA Micro-field Exposure tool is proposed, enabling precisely controlled exposures along with the EUV patterning of resists in vacuum. First measurements evaluating the impact of bandwidth selected exposures with a table-top set-up and subsequent EUV patterning show significant impact on line-edge roughness and process performance. We outline a simulation-based method for computing the effective flare from resist sensitive wavelengths as a function of mask pattern types and sizes. This simulation method is benchmarked against measured OOB flare measurements and the results obtained are in agreement.
Date: January 25, 2010
Creator: George, Simi; Naulleau, Patrick; Kemp, Charles; Denham, Paul & Rekawa, Senajith
Partner: UNT Libraries Government Documents Department

Mask roughness and its implications for LER at the 22- and 16-nm nodes

Description: Line-edge roughness (LER) remains the most significant challenge facing the development of extreme ultraviolet (EUV) resist. The mask, however, has been found to be a significant contributor to image-plane LER. This has long been expected based on modeling and has more recently been demonstrated experimentally. Problems arise from both mask-absorber LER as well as mask multilayer roughness leading to random phase variations in the reflected beam and consequently speckle. Understanding the implications this has on mask requirements for the 22-nm half pitch node and below is crucial. Modeling results indicate a replicated surface roughness (RSR) specification of 50 pm and a ruthenium capping layer roughness specification of 440 pm. Moreover, modeling indicates that it is crucial to achieve the current ITRS specifications for mask absorber LER which is significantly smaller than current capabilities.
Date: February 16, 2010
Creator: Naulleau, Patrick; George, Simi A. & McClinton, Brittany M.
Partner: UNT Libraries Government Documents Department

Simplified models for mask roughness induced LER

Description: The ITRS requires < 1.2nm line-edge roughness (LER) for the 22nm half-pitch node. Currently, we can consistently achieve only about 3nm LER. Further progress requires understanding the principle causes of LER. Much work has already been done on how both the resist and LER on the mask effect the final printed LER. What is poorly understood, however, is the extent to which system-level effects such as mask surface roughness, illumination conditions, and defocus couple to speckle at the image plane, and factor into LER limits. Presently, mask-roughness induced LER is studied via full 2D aerial image modeling and subsequent analysis of the resulting image. This method is time consuming and cumbersome. It is, therefore, the goal of this research to develop a useful 'rule-of-thumb' analytic model for mask roughness induced LER to expedite learning and understanding.
Date: February 21, 2011
Creator: McClinton, Brittany & Naulleau, Patrick
Partner: UNT Libraries Government Documents Department

Flight measurements of the effects of surface condition on the supersonic drag of fin-stabilized parabolic bodies of revolution

Description: Report presenting testing of rocket-powered models at supersonic speeds to determine some of the surface conditions on the zero-lift drag of fin-stabilized parabolic bodies of revolution. Two types of models and three types of surface roughness were tested. Results regarding mean-drag coefficients, side-pressure coefficients, and total-drag coefficients are provided.
Date: May 2, 1952
Creator: Jackson, H. Herbert
Partner: UNT Libraries Government Documents Department

An approximate method for calculating the effect of surface roughness on the drag of an airplane

Description: From Summary: "A method for computing the effect of surface roughness on the drag coefficient of an airplane is presented. Calculated results using this method are compared with experimental results from both flight and wind-tunnel tests. In general, the agreement is believed satisfactory."
Date: July 23, 1947
Creator: Hall, Charles F. & Fitzgerald, Fred F.
Partner: UNT Libraries Government Documents Department

Simplified method for determination of critical height of distributed roughness particles for boundary-layer transition at Mach numbers from 0 to 5

Description: Report presenting a simplified method that has been devised for the determination of the critical height of three-dimensional roughness particles required to promote premature transition of a laminar boundary layer on models of airplanes or airplane components. Results regarding the calculation of critical roughness height, minimization of roughness drag, limitations, and simplifying considerations are provided.
Date: September 1958
Creator: Braslow, Albert L. & Knox, Eugene C.
Partner: UNT Libraries Government Documents Department

Some effects of leading-edge roughness on the aileron effectiveness and drag of a thin rectangular wing employing a full-span plain aileron at Mach numbers from 0.6 to 1.5

Description: Report presenting an investigation of the effects of adding leading-edge roughness to the surfaces of an unswept, untapered, 6-percent-thick, circular-arc-airfoil wing equipped with a full-span, 0.2-chord, plain, trailing-edge aileron. Results regarding the rolling-effectiveness data, addition of roughness on a wing, and variation of drag coefficient are provided.
Date: November 4, 1953
Creator: English, Roland D.
Partner: UNT Libraries Government Documents Department

Effects of a typical nacelle on the characteristics of a thick low-drag airfoil critically affected by leading-edge roughness

Description: Report presenting testing to study the effects of a typical nacelle on the characteristics of a thick low-drag airfoil that was shown to be subject to separation difficulties due to leading edge roughness. This testing confirmed the results of previous tests which indicated that the airfoil was unconservative with respect to separation difficulties. Results regarding the internal-flow measurements and corresponding drag increments, external drag, leading-edge roughness and nacelle combination, and section lift comparisons are provided.
Date: April 1943
Creator: Ellis, Macon C., Jr.
Partner: UNT Libraries Government Documents Department

Experimental and model-based study of the robustness of line-edgeroughness metric extraction in the presence of noise

Description: As critical dimensions shrink, line edge and width roughness (LER and LWR) become of increasing concern. Crucial to the goal of reducing LER is its accurate characterization. LER has traditionally been represented as a single rms value. More recently the use of power spectral density (PSD), height-height correlation (HHCF), and {sigma} versus length plots has been proposed in order to extract the additional spatial descriptors of correlation length and roughness exponent. Here we perform a modeling-based noise-sensitivity study on the extraction of spatial descriptors from line-edge data as well as an experimental study of the robustness of these various descriptors using a large dataset of recent extreme-ultraviolet exposure data. The results show that in the presence of noise and in the large dataset limit, the PSD method provides higher accuracy in the extraction of the roughness exponent, whereas the HHCF method provides higher accuracy for the correlation length. On the other hand, when considering precision, the HHCF method is superior for both metrics.
Date: June 1, 2007
Creator: Naulleau, Patrick P. & Cain, Jason P.
Partner: UNT Libraries Government Documents Department

Spin-on-glass coatings for the generation of super-polishedsubstrates for extreme ultraviolet optics

Description: Substrates intended for use as extreme ultraviolet (EUV) optics have extremely stringent requirements in terms of finish. These requirements can dramatically increase the cost and fabrication time, especially when non-conventional shapes, such as toroids, are required. Here we present a spin-on-glass resist process capable of generating super-polished parts from inexpensive substrates. The method has been used to render diamond-turned substrates compatible for use as EUV optics. Toroidal diamond-turned optics with starting rms roughness in the 3.3 to 3.7 nm range have been smoothed to the 0.4 to 0.6 nm range. EUV reflectometry characterization of these optics has demonstrated reflectivities of approximately 63%.
Date: January 1, 2005
Creator: Salmassi, Farhad; Naulleau, Patrick P. & Gullikson, Eric M.
Partner: UNT Libraries Government Documents Department

Extreme ultraviolet mask substrate surface roughness effects on lithography patterning

Description: In extreme ultraviolet lithography exposure systems, mask substrate roughness induced scatter contributes to LER at the image plane. In this paper, the impact of mask substrate roughness on image plane speckle is explicitly evaluated. A programmed roughness mask was used to study the correlation between mask roughness metrics and wafer plane aerial image inspection. We find that the roughness measurements by top surface topography profile do not provide complete information on the scatter related speckle that leads to LER at the image plane. We suggest at wavelength characterization by imaging and/or scatter measurements into different frequencies as an alternative for a more comprehensive metrology of the mask substrate/multilayer roughness effects.
Date: June 21, 2010
Creator: George, Simi; Naulleau, Patrick; Salmassi, Farhad; Mochi, Iacopo; Gullikson, Eric; Goldberg, Kenneth et al.
Partner: UNT Libraries Government Documents Department

Mask roughness induced LER: a rule of thumb -- paper

Description: Much work has already been done on how both the resist and line-edge roughness (LER) on the mask affect the final printed LER. What is poorly understood, however, is the extent to which system-level effects such as mask surface roughness, illumination conditions, and defocus couple to speckle at the image plane, and currently factor into LER limits. Here, we propose a 'rule-of-thumb' simplified solution that provides a fast and powerful method to obtain mask roughness induced LER. We present modeling data on an older generation mask with a roughness of 230 pm as well as the ultimate target roughness of 50 pm. Moreover, we consider feature sizes of 50 nm and 22 nm, and show that as a function of correlation length, the LER peaks at the condition that the correlation length is approximately equal to the resolution of the imaging optic.
Date: March 12, 2010
Creator: McClinton, Brittany & Naulleau, Patrick
Partner: UNT Libraries Government Documents Department