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Tucson, AZ, United States

Sun T.,University of Arizona | Sun T.,Sichuan Normal University | Zhuang Y.,University of Arizona | Zhuang Y.,Araca, Inc. | And 3 more authors.
Microelectronic Engineering

Behavior of an eccentric PVA brush is investigated during post-Cu chemical mechanical planarization (CMP) brush cleaning. It is observed that the measured contact pressure and contact area of the eccentric brush vary significantly under different brush orientations. Moreover, the eccentric brush behaves differently from the good (i.e. concentric) brush in both the variance of shear force as well as the force spectra during cleaning. This study provides a rapid detection method to screen out eccentric brushes before they are used in semiconductor manufacturing, thereby potentially reducing wafer defects as well as chemical, water, and energy consumption associated with using eccentric PVA brushes. © 2012 Elsevier B.V. All rights reserved. Source

Jiao Y.,University of Arizona | Liao X.,University of Arizona | Wu C.,University of Arizona | Theng S.,Araca, Inc. | And 7 more authors.
Journal of the Electrochemical Society

An existing 300 mm CMP tool has been modified to polish 450 mm wafers in order to demonstrate experimentally whether any differences exist in the tribological and thermal characteristics of the two processes, and from that, to infer whether one can expect any removal rate differences between the two systems. Results suggest that, within the ranges of parameter investigated, the two systems behave similarly in terms of their coefficients of friction and lubrication regimes. Additionally, it is shown that the 450 mm process, once adjusted for its platen velocity, runs only slightly warmer (by 1-3C) than its 300 mm counterpart. Experimental data, coupled with copper removal rate simulations show that the wafer surface reaction temperature of the 450 mm process is slightly higher (by 1-2C) than the 300 mm process. Consequently, simulated copper removal rates for the 450 mm process are slightly higher (2-13) than those of the 300 mm process at most polishing conditions. The above results indicate that when the current 300mm CMP process is scaled up to 450 mm, the tribological, thermal, and kinetic attributes of the process remain similar and do not undergo significant changes. © 2012 The Electrochemical Society. Source

Liao X.,University of Arizona | Sampurno Y.,University of Arizona | Sampurno Y.,Araca, Inc. | Zhuang Y.,University of Arizona | And 6 more authors.
Microelectronic Engineering

The effect of retaining ring slot design and polishing conditions on slurry flow dynamics at the bow wave was investigated. An ultraviolet enhanced fluorescence technique was employed to measure the slurry film thickness at the bow wave for two polyetheretherketone (PEEK) retaining rings with different slot designs. Multiple sliding velocities, slurry flow rates and ring pressures were investigated. Results showed that the retaining ring with the sharp angle slot design (PEEK-1) generated significantly thicker slurry films at the bow wave than PEEK-2 which had a rounded angle slot design. For PEEK-1, film thickness at the bow wave increased with increasing flow rate and ring pressure and decreased with increasing sliding velocity. On the other hand, film thickness at bow wave did not change significantly for the PEEK-2 ring at different polishing conditions indicating an apparent robustness of the PEEK-2 design to various operating conditions. With retaining rings having different designs, and all else being the same, a thinner bow wave was preferred since it was indicative of a ring design that allowed more slurry to flow into the pad-wafer interface. Therefore, the work underscored the importance of optimizing retaining ring slot design and polishing conditions for efficient slurry utilization. © 2012 Elsevier B.V. All rights reserved. Source

Sampurno Y.,University of Arizona | Sampurno Y.,Araca, Inc. | Sudargho F.,University of Arizona | Sudargho F.,Araca, Inc. | And 6 more authors.
Microelectronic Engineering

This study explores the transition of force spectral fingerprints of shallow trench isolation chemical mechanical planarization during early evolution of wafer topography and layer transition from silicon dioxide to silicon nitride. Polishing was done on a polisher and tribometer capable of measuring shear force and down force in real-time. Fast Fourier Transformation is performed to convert the force data from time domain to frequency domain and to illustrate the spectral amplitude distribution of the force. Such frequency spectra provide in-depth insights into the interactions among abrasive particles, pad and wafer. Shallow trench isolation patterned wafers are over-polished using cerium oxide slurry. Results show that shear force increases during polishing when the silicon dioxide layer is removed thus exposing the silicon nitride layer. Unique and consistent spectral fingerprints are generated showing significant changes in several fundamental peaks during the early evolution of wafer topography and subsequent layer transition to silicon nitride polishing. Variance of force is also plotted to show the progression of pattern evolution. Results show that a combination of unique spectral fingerprinting, coefficient of friction as well as analyses of force and its variance (based on shear and down force) can be used as to monitor in real-time the polishing progress during shallow trench isolation chemical mechanical planarization. © 2011 Elsevier B.V. All rights reserved. Source

Mu Y.,University of Arizona | Han R.,University of Arizona | Sampurno Y.,University of Arizona | Sampurno Y.,Araca, Inc. | And 4 more authors.
ECS Journal of Solid State Science and Technology

Slurry mean residence time, dispersion number, removal rate, coefficient of friction, and pad temperature were analyzed for standard pad center area slurry application and two configurations (Design A and Design B) of the novel slurry injection system (SIS) used in chemical mechanical planarization. The novel SIS was placed on the pad surface and slurry was injected through an inlet port which matched an outlet at the trailing edge of the injector bottom. SIS having Design A has flat leaDing edge to prevent, as much as possible, spent slurry or residual water from re-entering the pad-wafer interface. In contrast, Design B possesses several notches on its leaDing edge for the temporary accumulation of a small amount of spent slurry. Results showed both configurations of the novel SIS generated lower coefficient of friction and pad temperature, shorter slurry mean residence time, smaller dispersion number and higher removal rate than the standard pad center area slurry application method. Design B has a higher mean residence time and larger dispersion number than Design A since Design B allows more spent slurry/residual rinse water to re-enter the pad-wafer interface than Design A. This work underscores the importance of slurry injection method for achieving optimum chemical mechanical planarization processes. © 2015 The Electrochemical Society. Source

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