Particle adhesion and removal mechanisms in post-CMP cleaning processes

Busnaina, Ahmed; Lin, Hong Ming; Moumen, N.; Feng, Jiangwei; Taylor, J.

doi:10.1109/tsm.2002.804872

Cited by 109 publications

(69 citation statements)

References 7 publications

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“…The microspheres should be dry when they are applied to the coverslip. We find that microspheres deposited on a coverslip directly from a solution (water or acetone) cannot be launched [62,63].…”

Section: Launching Microspheresmentioning

confidence: 92%

Fundamental Tests of Physics with Optically Trapped Microspheres

2013

Springer Theses

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We have trapped glass microspheres in water, air and vacuum with optical tweezers. We developed a detection system that can monitor the position of a trapped microsphere withÅngstrom spatial resolution and microsecond temporal resolution. We studied the Brownian motion of a trapped microsphere in air over a wide range of pressures. We measured the instantaneous velocity of a Brownian particle. Our results provide direct verification of the Maxwell-Boltzmann velocity distribution and the energy equipartition theorem for a Brownian particle. For short time scales, the ballistic regime of Brownian motion is observed, in contrast to the usual diffusive regime. We are currently developing a new detection system to measure the instantaneous velocity of a Brownian particle in water.viii In vacuum, we have used active feedback to cool the three center-ofmass vibration modes of a trapped microsphere from room temperature to millikelvin temperatures with a minimum mode temperature of 1.5 mK, which corresponds to the reduction of the root mean square (rms) amplitude of the microsphere from 6.7 nm to 15 pm for that mode. The mean thermal occupa-

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Section: Launching Microspheresmentioning

confidence: 92%

Fundamental Tests of Physics with Optically Trapped Microspheres

2013

Springer Theses

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“…Busnaina et al [30] found that full contact between a brush and a particle is necessary to lift or roll particles smaller than 0.1 mm off a substrate.…”

Section: Brush Cleaningmentioning

confidence: 99%

“…30 AFM images of the copper surface after polishing in (a) a DI water based alumina slurry, (b) a DI water based silica slurry, (c) a citric acid-based alumina slurry, and (d) a citric acid based silica slurry at pH 6.…”

mentioning

confidence: 99%

Post‐CMP Cleaning

Park

Kim

2007

Microelectronic Applications of Chemical Mechanical Planarization

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With the decrease in device feature sizes, planarization of both front-and back-end layers by the chemical-mechanical planarization (CMP) process has become necessary for integrated circuit (IC) fabrication technologies smaller than 0.35 mm. As much as the industry has benefitted tremendously from the introduction and implementation of CMP, the very process has also brought along a set of new challenges to the fabs. For example, surface defects or imperfections such as leftover particles, organic residues, metallic contaminations, scratches, and corrosion spots can often be found on the polished wafers after the CMP process. These CMP-induced defects can arise from the slurries, the polishing pad, the pad conditioner, and to a lesser extent, the polisher. The leftover particles can physically attach to the wafer surface or, in the worst case, even partially embed into the top layer of a wafer. The CMP process can also leave metallic contamination typically in the range of 10 11 -10 12 atoms/ cm 2 . These contaminants mainly arise from the abraded metal lines, metal ions in the slurries, and polishers. In front-end applications such as a shallow trench isolation (STI) process, the control of metallic contamination levels is very critical because the following high-temperature process may lead to a complete incorporation of the metal ions into the lattice. In the case of back-end processes, if not removed, these metal contaminants can lower the breakdown voltage of devices. Also, fast diffusers such as copper can reach the active area from the backside surface or edge during the following thermal process [1]. During CMP, slurry additives and pad debris can leave organic residues on the Microelectronic Applications of Chemical Mechanical Planarization, Edited by Yuzhuo Li

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“…The velocity profile between the substrate surface and the brush surface is usually assumed to be linear for simplicity [1][2][3]. However, the flow field comprised by the substrate and brush actually form a thin layer fluid flow because the brush usually is located very close to the wafer surface to generate a larger drag force.…”

Section: Drag Forcementioning

confidence: 99%

“…The currently used post-CMP cleaning techniques include brush scrubbing [1][2][3], ultrasonic and megasonic cleaning [4], fluid jet cleaning [5], laser heating [6] and chemical dissolution [7]. All of these techniques have practical limitations.…”

Section: Introductionmentioning

confidence: 99%

Modeling of Particle Removal using Non-contact Brush Scrubbing in Post-CMP Cleaning Processes

Chein

Liao

2006

The Journal of Adhesion

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Particle removal using non-contact brush scrubbing for post-CMP (Chemical Mechanical Planarization) cleaning is investigated analytically. The removal of SiO 2 and Al 2 O 3 particles adhered onto SiO 2 film coated on the wafer surface are considered. The cleaning fluid (H 2 O=NH 4 OH ¼ 1:25 and 1:200) flowing between the brush and wafer surface is treated as a thin-film fluid flow. The flow field details and its effect on the drag force acting on the adhered particles are discussed. In addition to the drag force, the electrical double layer (EDL) and thermophoretic force effects on particle removal are also considered. It was found that the dominant force in achieving particle removal using a rolling mechanism is the drag force. The EDL and thermophoretic forces have an insignificant effect on particle removal. Based on the results from this study, particles of submicron size can be removed from a wafer surface using higher brush rotation speed and pure deionized (DI) water as the cleaning fluid.

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Particle adhesion and removal mechanisms in post-CMP cleaning processes

Cited by 109 publications

References 7 publications

Fundamental Tests of Physics with Optically Trapped Microspheres

Fundamental Tests of Physics with Optically Trapped Microspheres

Post‐CMP Cleaning

Modeling of Particle Removal using Non-contact Brush Scrubbing in Post-CMP Cleaning Processes

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