Studies of the Relationship between Megasonics, Surface Etching, and Particle Removal in SC-1 Solutions

ABSTRACTWafer cleaning studies have been performed so as to understand the influence of acoustic (megasonic) energy on particle removal in dilute SC-1 solutions. Surface etching alone (up to 60Å) has been found to be insufficient to completely remove silicon nitride surface particles from native oxide surfaces in the absence of megasonics. For megasonic cleaning processes the minimum surface etching required for complete nitride particle removal is significantly lower (between 3–12Å) than for a non-megasonic process. The exact 'threshold' for surface etching will depend on the chemical nature of the particle/surface and the megasonics power. Megasonics energy does not appear to enhance chemical etching of the substrate, at least for silicon oxide substrates, however, it significantly improves particle removal. This data suggests that the particle removal process can benefit from both a thermally activated component (etching) as well as an acoustic component (cavitation/ acoustic streaming).

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High Efficiency Single Wafer Cleaning for Wafer Bonding-Based 3D Integration Applications

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.187.269 ◽

2012 ◽

Vol 187 ◽

pp. 269-272 ◽

Cited By ~ 3

Author(s):

Don Dussault ◽

F. Fournel ◽

V. Dragoi

Keyword(s):

Removal Efficiency ◽

Wafer Bonding ◽

High Efficiency ◽

Current Work ◽

Particle Removal ◽

3D Integration ◽

Production Scale ◽

Megasonic Cleaning ◽

Wafer Cleaning ◽

Transducer Design

Current work describes development, testing and verification of a single wafer megasonic cleaning method utilizing a transducer design that meets the extreme particle neutrality, Particle Removal Efficiency (PRE), and repeatability requirements of production scale wafer bonding and other applications requiring extremely low particle levels.

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Megasonic Cleaning to Remove Nano-Dimensional Contaminants from Wafer Surfaces: An Analytical Study

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.195.209 ◽

2012 ◽

Vol 195 ◽

pp. 209-212

Author(s):

R. Nagarajan ◽

S. Jain ◽

M.A. Prabhudesai ◽

A. Khanolkar ◽

M.P. Reddy ◽

...

Keyword(s):

Integrated Circuit ◽

Analytical Study ◽

Printed Circuit Board ◽

Acoustic Streaming ◽

Circuit Board ◽

Thin Boundary Layer ◽

Megasonic Cleaning ◽

Wafer Cleaning ◽

Silicon Wafer Cleaning ◽

Wafer Surfaces

Megasonic cleaning traditionally refers to use of acoustic fields in the 800 kHz 1 MHz range to remove contaminants adhered to surfaces immersed in liquid media. However, even fields driven by frequencies in the > 400 kHz regime exhibit virtually all characteristics of conventional megasonics. These include: unidirectional pumped flow of liquid (acoustic streaming) normal to the transducer, at velocities that scale as square of frequency; and, a near-absence of cavitational phenomena associated with ultrasonic cleaning. For the latter reason, megasonic cleaning is preferred over ultrasonics when attempting to remove contaminants from delicate, fragile, erodible or feature-rich surfaces. Silicon wafer cleaning in semiconductor manufacturing, integrated circuit cleaning, and printed circuit board cleaning have utilized megasonics (with appropriate chemistry) for several decades. The megasonic frequency offers the additional benefit of a very thin boundary layer over the immersed surface, which effectively exposes even sub-micron and nanodimensional particles to the flow of the cleaning liquid.

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Practical considerations in Megasonic Wafer Cleaning

MRS Proceedings ◽

10.1557/proc-477-15 ◽

1997 ◽

Vol 477 ◽

Author(s):

R. Mark Hall ◽

Taura Jarvis ◽

Thad Parry

Keyword(s):

Experimental Data ◽

Surface Roughness ◽

Bath Temperature ◽

Process Time ◽

Particle Removal ◽

Megasonic Cleaning ◽

Wafer Cleaning ◽

Transducer Design ◽

Gap Spacing ◽

The Impact

ABSTRACTIn this study, critical hardware and process parameters are evaluated for their effect on performance in megasonic cleaning applications. Experimental data is presented which shows the impact of transducer design, bath temperature, process time, SC1 chemistry, and wafer gap spacing on particle removal and surface roughness. The ability to remove particles smaller than 0.1 um in size is also demonstrated.

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Acoustic Field Analysis of a T Type Waveguide in Single Wafer Megasonic Cleaning and its Effect on Particle Removal

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.134.229 ◽

2007 ◽

Vol 134 ◽

pp. 229-232 ◽

Cited By ~ 1

Author(s):

Yang Lae Lee ◽

Eui Su Lim ◽

Kook Jin Kang ◽

Hyun Se Kim ◽

Tae Gon Kim ◽

...

Keyword(s):

Finite Element Method ◽

Acoustic Pressure ◽

Field Analysis ◽

Particle Removal ◽

Pressure Measurements ◽

Cleaning Efficiency ◽

Transverse Waves ◽

Megasonic Cleaning ◽

Longitudinal Waves ◽

Wafer Cleaning

T type megasonic waveguide was analyzed by finite element method (FEM), acoustic pressure measurements and particle removal efficiency for the single wafer cleaning application. Compared to conventional longitudinal waves, a transverse waves were generated in a T type waveguide. Not like longitudinal waves, transverse waves showed changes of direction and phase which increased the cleaning efficiency.

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Noncontact Physical Removal of Nano-Scale Particles From Surfaces

10.1115/imece2001/mems-23918 ◽

2001 ◽

Author(s):

Ahmed A. Busnaina ◽

Hong Lin

Keyword(s):

Semiconductor Manufacturing ◽

Pressure Fluctuations ◽

Acoustic Streaming ◽

Particle Removal ◽

Cleaning Process ◽

Sound Waves ◽

Megasonic Cleaning ◽

Nano Scale ◽

Technology Roadmap ◽

Sonic Energy

Abstract With the International Technology Roadmap for Semiconductors decreasing the particle removal requirements from 125nm (0.3–0.75/cm2) in 1997 to 25nm (0.01–0.15/cm2) in 2011, an era of the most challenging cleaning applications in semiconductor manufacturing is upon us [1. Megasonic cleaning is a widely used non-contact cleaning technique. In megasonic cleaning, wafers are immersed in a cleaning liquid medium to which sonic energy is applied. High intensity sound waves generate pressure fluctuations and acoustic streaming which detach the particles from the surface and remove them. Busnaina et al [2–3 studied megasonic particle removal and the effect of acoustic streaming on the cleaning process especially in post-CMP applications. It is important to know the advantage and the limitation of megasonic cleaning technique in nano-scale particles removal.

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SI3N4 Particle Removal Efficiency Study

MRS Proceedings ◽

10.1557/proc-477-27 ◽

1997 ◽

Vol 477 ◽

Cited By ~ 1

Author(s):

Jane Qian Liu ◽

Carolyn Lee ◽

Joseph M. Rosamilia ◽

Tom Boone ◽

Veronica Czitrom ◽

...

Keyword(s):

Removal Efficiency ◽

Defect Density ◽

Bath Temperature ◽

Solution Chemistry ◽

Particle Removal ◽

Megasonic Cleaning ◽

Wafer Cleaning ◽

Particle Contamination ◽

The Impact ◽

Improve Device

ABSTRACTControlling particle contamination in wafer cleaning is important to reduce defect density and improve device performance and yield. In this study, a screening experiment was employed to evaluate particle removal efficiency among different cleanings, including FSI BCLN, bench rinse and dry only, bench SC1/megasonic only, bench RCA cleaning, and bench RCA-based cleaning. To optimize particle removal efficiency in RCA-based cleaning, a design of experiment (DOE) has been done to investigate the impact of SC1/megasonic cleaning on Si3N4 particle removal efficiency. Bath temperature, megasonic power, and solution chemistry of SCI bath were evaluated. The removal efficiency in relations to particle sizes was also investigated

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Post-CMP Megasonic Cleaning Using Dilute SCI Solution

MRS Proceedings ◽

10.1557/proc-566-247 ◽

1999 ◽

Vol 566 ◽

Cited By ~ 1

Author(s):

A. A. Busnaina ◽

N. Moumen ◽

J. Piboontum ◽

M. Guarrera

Keyword(s):

High Frequency ◽

Semiconductor Manufacturing ◽

Acoustic Streaming ◽

Wafer Surface ◽

Particle Removal ◽

Optimum Conditions ◽

Small Particles ◽

Cleaning Efficiency ◽

Megasonic Cleaning ◽

Thermal Oxide

Non contact cleaning or wet-cleaning processes, were the megasonic play a key role in the separation of the particles from the wafer is a commonly used technique in semiconductor manufacturing. CMP process can be very damaging to the production yield if not followed by an effective post clean process. McQueen identified the effect of the acoustic boundary layer and its role in the removal of small particles at high frequency. Busnaina et alt studied ultrasonic and megasonic particle removal and the effect of acoustic streaming. They showed that the cleaning efficiency increased with power until a certain range and then decrease slightly. Busnaina et al result indicted that SCI removes more particles than DI water particularly at lower megasonic powers specially in the case were the slurry particles are deposited onto the wafer surface by dipping experiments. But they also demonstrated that it was possible to achieve 100 % removal in DI water when using the optimum conditions. This paper presents the latest results of the post-CMP megasonic cleaning process, this study is focused on the cleaning of thermal oxide silicone wafer polished using silica based slurry and cleaned using diluted SC1 (H20/H202/NH4OH: 40/2/1).

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Fine Particle Removal Using High Frequency Acoustic Streaming

Volume 5: 17th Computers in Engineering Conference ◽

10.1115/detc97/cie-4436 ◽

1997 ◽

Author(s):

Ahmed A. Busnaina

Keyword(s):

Removal Efficiency ◽

High Frequency ◽

Acoustic Streaming ◽

Input Power ◽

Polystyrene Latex ◽

Maximum Power ◽

Solution Temperature ◽

Particle Removal ◽

Megasonic Cleaning ◽

Particulate Contamination

Abstract Liquid-based cleaning is extensively used in the semiconductor and other industries affected by contamination for the removal of particulate contamination. One of the widely used wet-cleaning processes is the megasonic cleaning. The megasonics term is used in industry to refer to frequencies near 1 MHZ. Megasonic cleaning techniques used today in industry were first presented by RCA scientists [1,6,7]. McQueen [4,5] identified the effect of the acoustic boundary layer and its role in the removal of small particles at high frequency. Kashkoush, Busnaina et al [8–11] studied ultrasonic and megasonic particle removal, focusing on the effects of acoustic streaming. They showed that removal percentage increased with power. Their results also indicated different removal efficiencies for polystyrene latex (PSL), silica (SiO2) and silicon nitride (Si3 N4) particles. Megasonic cleaning using SC1 and SC2 chemistry has been shown to be very effective by Syverson, et. al. [12]. They also showed that the removal efficiency increased with power up to a 150 W (maximum power available). Wang et al [13] also showed that power had the greatest influence on the removal efficiency up to a maximum power available (150 W). These results are consistent with what was observed by Kashkoush, Busnaina and Gale [12,13]. However, Gale and Busnaina [14–17], using higher power megasonics up to 800 W, showed that the highest removal efficiency occurs at an optimum power (500–600 W) above which it decreases slightly. They also showed that megasonic input power has the greatest influence on particle removal efficiency as compared to solution temperature, both in water and in SC1 solution. They also showed that SC1 removes particles more efficiently than DI water, particularly at lower megasonic powers. But they also showed that it was still possible to achieve 100% removal in DI water under the proper conditions.

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