Float-polishing process and analysis of float-polished quartz

Soãres, Schubert; Baselt, David R.; Black, James P.; Jungling, K. C.; Stowell, W. K.

doi:10.1364/ao.33.000089

Cited by 47 publications

(16 citation statements)

References 8 publications

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“…The linear form of Eq. 14 is given by [15] Discussion CMP polishing rates have historically been described by the Preston equation, written as [16] where h is the thickness of the substrate being polished, s is the total sliding distance traveled by the substrate, N is the normally applied load on area A, and t is time. Equation 16 shows that the removal rate increases linearly with the platen speed.…”

Section: Modelingmentioning

confidence: 99%

“…Researchers have focused on individual aspects of the process, such as slurry chemistry, 1-5 wafer-pad dynamics, 6-8 mechanisms, [9][10][11][12][13][14] and numerical simulations of the slurry fluid mechanics. [15][16][17] There has been, however, little experimental research regarding slurry fluid mechanics.Several researchers have commented on the importance of slurry flow and slurry distribution beneath the wafer although the importance of slurry flow has not been experimentally demonstrated. Stavreva et al 18 discussed how the pad's ability to transport slurry could affect the polishing rate and uniformity during copper CMP.…”

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confidence: 99%

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Investigating Slurry Transport Beneath a Wafer during Chemical Mechanical Polishing Processes

Coppeta

Rogers

Racz

et al. 2000

J. Electrochem. Soc.

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Since its introduction into integrated circuit (IC) manufacturing by IBM Corporation in the mid-1980s, chemical mechanical planarization (CMP) has become a key enabling technology in the semiconductor industry. All of the major IC manufacturers including Intel, Motorola, and IBM now incorporate CMP in the production of their chips. In addition to IC production, CMP applications have spread into other manufacturing processes including dynamic random access memory (DRAM) chips, hard drives, and modem chips.Given the magnitude of capital invested in this technology, there is a large impetus to develop a fundamental understanding of the process. Research with this goal in mind is being performed; however, an overall understanding of the process remains elusive because of the multidisciplinary nature of CMP. Researchers have focused on individual aspects of the process, such as slurry chemistry, 1-5 wafer-pad dynamics, 6-8 mechanisms, [9][10][11][12][13][14] and numerical simulations of the slurry fluid mechanics. [15][16][17] There has been, however, little experimental research regarding slurry fluid mechanics.Several researchers have commented on the importance of slurry flow and slurry distribution beneath the wafer although the importance of slurry flow has not been experimentally demonstrated. Stavreva et al. 18 discussed how the pad's ability to transport slurry could affect the polishing rate and uniformity during copper CMP. Parikh found that slurry flow rate had a large effect on the polishing uniformity on an orbital polisher. 19 Ali et al. 20 stated that the slurry composition, flow rate, and direction of slurry impingement onto the polishing pad all play important roles in interdielectric removal rates. Singer 21 reported that the manner in which slurry is transported from the outside of the wafer to its center is critically important. Sugimoto et al. 22 showed that slurry transport in grooved pads is important in reducing thermal gradients across a wafer. Since polishing rates are temperature dependent, a reduction in thermal gradients across the wafer is believed to reduce the within-wafer-nonuniformity. Ali et al. 23 postulated that the degradation in the removal rates of pads without conditioning is due to the decrease in the pad's slurry holding capacity. Liang et al. 24 postulated that Cabot's new open cell pads do not need macroscopic surface topography because of the pad's efficiency in channeling the slurry. Despite the fact that slurry flow generally is considered to be an important factor in the CMP process, there has not been an experimental study of the slurry flow or a numerical simulation sophisticated enough to examine the slurry behavior under realistic conditions. Slurry transport and mixing could influence the polishing performance in two ways: (i) transport of polished material and (ii) nonuniform slurry transport. The first mechanism was postulated by Cook in his research on glass polishing. 4 Cook suggested that polishing removal rate is influenced by the transport of polished materi...

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Section: Modelingmentioning

confidence: 99%

mentioning

confidence: 99%

Investigating Slurry Transport Beneath a Wafer during Chemical Mechanical Polishing Processes

Coppeta

Rogers

Racz

et al. 2000

J. Electrochem. Soc.

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show abstract

“…Several polishing techniques, such as float polishing, Teflon polishing, magnetorheological finishing (MRF) and ion beam polishing etc, can fabricate supersmooth surfaces [1,2] . But, to produce 100mm-diameter scale optical elements with ultra-flat and supersmooth surfaces is still a challenge in optical fabrication.…”

Section: Introductionmentioning

confidence: 99%

Fabrication and quantitative characterization of super smooth surface with sub-nanometer roughness

Shen

Ding

et al. 2010

Seventh International Conference on Thin Film Physics and Applications

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There is a growing requirement to use supersmooth surfaces with roughness in the sub-nanometer range. But, to produce 100mm-diameter optical elements with ultra-flat and supersmooth surfaces is still difficult. The fabrication technique based on continues polishing process is presented to produce flat optical element with extremely smooth surface. During the fabrication, A concept of "Process Controlling" is introduced, which means the machining of super-smooth surfaces is considered as a chain consisted of some key nodes, not merely a polishing process. The surface figure is tested using interferometer and the surface roughness is using interference microscopy and atom force microscopy (AFM) repectively. Then the Power Spectral Density (PSD) function, including the basic theory and the physical meaning, are presented to explain the difference of test results, which is measured by optical profiler and AFM with different parameters. The polynomial fitting results indicate that there is excellent agreement between measurements made by the two instruments.

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“…At present, Supersmooth surfaces can be obtained by special polishing techniques, for example, float polishing, Teflon polishing, chemical mechanical polishing, and magnetorheological finishing (MRF), laser polishing， plasma-assisted chemical etching (PACE) polishing and ion beam polishing etc [1][2][3][4][5][6] . But, to produce big aperture optical elements with flat and supersmooth surfaces with atomic scale roughness is still a challenge in optical fabrication.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of flat and supersmooth surfaces with bowl-feed polishing process

Shen

Wang

et al. 2007

3rd International Symposium on Advanced Optical Manufacturing and Testing Technologies: Advanced Optical Manufacturing Technolo

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Low-scatter supersmooth optical components are wildly used for critical applications such as high power laser systems, mirrors for ring laser gyros, and low-scatter windows. In this paper, a bowl-feed polishing process with fine abrasives to get flat and extremely smooth surfaces is presented. We consider the machining of super-smooth surfaces as a chain consisted of some key nodes, not merely a polishing process. So after the samples of fused silica have been grinded, fine grinded and lapping previously, each step is controlled strictly, a bowl-feed polishing process is adopted to produce the supersmooth surfaces. During the whole polishing process, in order to achieve consistently reliable and meaningful values of both roughness and flatness, every effort is made to get the proper polishing parameters. Abrasives with different grain size distribution and the temperature are taken into account particularly. Two characters of the samples, roughness and flatness, are concerned about in this study. Process controlling by interferometer implies that surface shape is maintained to better than λ/15 RMS (λ=632.8nm), 100 mm in diameter for an extended periods of time, of the order of days. The surface roughness is tested by an interference microscopy. In best cases, the final test result of surface roughness is better than 0.8nm RMS.

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Float-polishing process and analysis of float-polished quartz

Cited by 47 publications

References 8 publications

Investigating Slurry Transport Beneath a Wafer during Chemical Mechanical Polishing Processes

Investigating Slurry Transport Beneath a Wafer during Chemical Mechanical Polishing Processes

Fabrication and quantitative characterization of super smooth surface with sub-nanometer roughness

Fabrication of flat and supersmooth surfaces with bowl-feed polishing process

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