Simulated Effects of Measurement Noise on Contact Measurements Between Rough and Smooth Surfaces

Gray, Caprice; White, Robert D.; Manno, Vincent P.; Rogers, Chris

doi:10.1007/s11249-007-9295-9

Cited by 3 publications

(2 citation statements)

References 19 publications

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“…Although a number of researchers have measured the global average shear force in situ, 2,[8][9][10] there is reason to think that the actual interaction forces present at the pad wafer interface are not well distributed, but are concentrated at relatively small points of contact. Research from our group 11,12 and from other sources 13 suggests that the pad-wafer contact percentage is on the order of 1% or below. Thus microscale forces at interaction regions are likely to be 100 times or more higher than a simple area average would suggest.…”

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confidence: 96%

Measurement of Microscale Shear Forces during Chemical Mechanical Planarization

White

Mueller

Shin

et al. 2011

J. Electrochem. Soc.

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Polydimethylsiloxane (PDMS) posts with a diameter of 80 m were used to measure the shearing forces at the wafer-pad interface during chemical mechanical planarization (CMP). Measurements are made at 10 kHz with measurable forces between 40 and 400 N. The structures were polished using a stiff, ungrooved pad and 3 wt % fumed silica slurry at velocities of 0.3 and 0.6 m/s and average wafer-pad normal load of 5.0 and 9.1 kPa. Due to the small fraction of the pad that contacts the wafer, the local microscale forces can be much larger than the global average force might suggest. Observed lateral forces on the structures averaged, in time, between 230 and 310 N with RMS deviations of the force about the mean between 47 and 64 N. The faster polishing case shows a 30% higher mean force, and a 20% reduction in the RMS variation of force. Little change is seen in the force characteristics when increasing from 5.0 to 9.1 kPa downforce. A mathematical model is developed to interpret these forces, allowing estimation of the local pad properties. The model suggests that 5000 asperity contacts are present per square millimeter, asperity lateral stiffness is 0.3 N/m, and asperity slip-off force is 19 N.

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confidence: 96%

Measurement of Microscale Shear Forces during Chemical Mechanical Planarization

White

Mueller

Shin

et al. 2011

J. Electrochem. Soc.

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“…Optical methods such as “interferometry, confocal reflectance interference contrast microscopy (C‐RICM) and Dual Emission Laser‐Induced Fluorescence (DELIF)” can also be employed to observe microscale effects if one of the surfaces is clear or is modified to contain an optical window (Gray et al , 2008). “During the 1950s and 1960s, with the advent of photoelastic techniques, studies were performed using transparent araldite models to calculate stress distributions between curved surfaces” (Pau et al , 2000).…”

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confidence: 99%

A comparison of methods to evaluate the behavior of finite element models with rough surfaces

Thompson¹

2011

Scanning

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Finite element (FE) modeling of rough surfaces is becoming increasingly common. However, the quality of the assumptions being made in these models, and thus the quality of the models themselves, is often unclear. Decisions about the geometry of the surface to be modeled, including the size of the surface to be modeled, the lateral resolution of the measured surface data to be used, and the formulation of the probabilistic surface to be used, can have a significant effect on a model's behavior. Similarly, varying model parameters, including the FE mesh density, can change the results by a factor of three or more. This work examines some of the metrics that can be used to evaluate the influence of these assumptions and parameters on FE models with rough surfaces and discusses the relative merits of each option. In particular, qualitative comparison of result plots, quantitative comparison and convergence of results parameters, qualitative and quantitative comparison of distributions of result values over various model dimensions, and more sophisticated comparison techniques inspired by image and signal processing are discussed.

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Experimental Strategies for Studying Tribo-Electrochemical Aspects of Chemical–Mechanical Planarization

Gamagedara,

Roy

2024

Lubricants

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Chemical–mechanical planarization (CMP) is used to smoothen the topographies of a rough surface by combining several functions of tribology (friction, lubrication), chemistry, and electrochemistry (corrosion, wear, tribo-corrosion). The surface layer of interest is structurally weakened by the chemical and/or electrochemical reactions of selected additives in a polishing slurry, and the modified surface is flattened by the abrasion of a polishing pad with or without abrasive particles. The chemically active CMP slurry also serves as a lubricant for polishing and enables planarization at a microscopic level while avoiding the formation of defects at the processed surface. Applications of CMP are wide-ranging in various material-processing technologies and, specifically, it is a critical manufacturing step of integrated circuits. The CMP of metals is a significant part of this processing scheme and is associated with highly complex tribo-electrochemical mechanisms that are now additionally challenging due to various new requirements of the advanced technology nodes. The present review examines the current statuses of experimental strategies for collecting important mechanistic details of metal CMP that are necessary to design and assess CMP consumables. Both traditional and underexplored experimental techniques are discussed with illustrative results, including many previously unpublished findings for certain CMP systems of current interest.

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Simulated Effects of Measurement Noise on Contact Measurements Between Rough and Smooth Surfaces

Cited by 3 publications

References 19 publications

Measurement of Microscale Shear Forces during Chemical Mechanical Planarization

Measurement of Microscale Shear Forces during Chemical Mechanical Planarization

A comparison of methods to evaluate the behavior of finite element models with rough surfaces

Experimental Strategies for Studying Tribo-Electrochemical Aspects of Chemical–Mechanical Planarization

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