Liquid‐Phase Processing of Hydrophilic Features on a Silicon Wafer

Olim, M.

doi:10.1149/1.1838187

Cited by 14 publications

(8 citation statements)

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“…This could be because surface tension prevents the interface from deforming as necessary (De Gennes et al, 2004), the material to be cleaned has poor wettability, or dead-end structures do not allow gas to escape. For these reasons, a number of trials have investigated gas dissolution (Olim, 1997), the use of supercritical fluids (Ota and Tutsumi, 2008), and the wettability and influence of dissolved gas (Ota and Tutsumi, 2007).…”

Section: Introductionmentioning

confidence: 99%

Observation of liquid infiltration process into closed-end holes by droplet train impingement

Sanada

Furuya

Muraki

et al. 2018

JFST

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Wet cleaning methods using liquids are widely applied in many industrial fields. In such methods, it is first necessary to cover the object to be cleaned with the liquid. However, in structures with small holes, surface tension prevents the deformation of the gas-liquid interface, making it difficult to fill the object with the liquid. We have found that liquid infiltration into such small holes is promoted by the impingement of droplet trains, but the underlying mechanism has not yet been elucidated. In this study, we observed this liquid infiltration process through droplet train impingement into a closed-end hole, and compared the liquid column impact. The filling process was visualized with two high-speed video cameras. Our observations illustrate the importance of the oscillation and deformation of the gas-liquid interface inside the holes following droplet impingement. First, intermittent droplet impingement causes small droplets or large interface deformations to form, and then the gas column inside the hole becomes separated. This separated gas column is then gradually ejected. Therefore, the liquid infiltration can be increased by using a droplet train formed of a small-surface-tension liquid. Furthermore, we investigated the influence of the hole diameter and the uniformity of the droplet train frequency. The results show that droplet train impingement is effective for relatively large holes, although the uniformity of the droplet train frequency has little effect on the liquid infiltration.

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Section: Introductionmentioning

confidence: 99%

Observation of liquid infiltration process into closed-end holes by droplet train impingement

Sanada

Furuya

Muraki

et al. 2018

JFST

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“…We measured the gas column area S G and liquid entering area S L using MATLAB before and after irradiation by acoustic waves. Equation (1) shows the definition of r.…”

Section: Methodsmentioning

confidence: 99%

“…Cleaning, painting, and bonding using liquids are indispensable in product manufacturing. To completely achieve these processes, the inside of surface holes must be filled with liquid [1][2][3]. This is easy in a through-hole or larger diameter hole due to capillary action or Rayleigh-Taylor instability.…”

Section: Introductionmentioning

confidence: 99%

Removing Gas from a Closed-End Small Hole by Irradiating Acoustic Waves with Two Frequencies

2022

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Filling microstructures in the air with liquid or removing trapped gases from a surface in a liquid are required in processes such as cleaning, bonding, and painting. However, it is difficult to deform the gas–liquid interface to fill a small hole with liquid when surface tension has closed one end. Therefore, it is necessary to have an efficient method of removing gas from closed-end holes in liquids. Here, we demonstrate the gas-removing method using acoustic waves from small holes. We observed gas column oscillation by changing the hole size, wettability, and liquid surface tension to clarify the mechanism. First, we found that combining two different frequencies enabled complete gas removal in water within 2 s. From high-speed observation, about half of the removal was dominated by droplet or film formation caused by oscillating the gas column. The other half was dominated by approaching and coalescing the divided gas column. We conclude that the natural frequency of both the air column and the bubbles inside the tube are important.

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“…Few studies have been reported that attempt to model liquid-phase processes and the various steps of the process mechanism, but those that have been reported [2][3][4][5][6] generally neglect this first step by assuming that complete surface wetting occurs instantaneously. However, this assumption can be invalid: wetting is obstructed in features such as high-aspect-ratio vias and trenches, and on surfaces that exhibit a high contact angle in contact with process liquids, i.e., organic polymer dielectrics in contact with aqueous solutions.…”

mentioning

confidence: 99%

“…A recent analysis 6 investigates the wetting mechanism but concludes that wetting time is an insignificant contributor to total processing time; for example, a 0.5 m wide feature with a height of 4 m was estimated to fill in less than 1 s. 6 This study was performed for specific liquid properties in the limit of steady-state transport dominated by diffusion only in the feature. The time dependence of wetting and the resistance to mass transfer outside the feature are neglected.…”

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confidence: 99%

Incomplete Wetting of Nanoscale Thin-Film Structures

Spuller

Hess

2003

J. Electrochem. Soc.

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With each new generation of integrated circuits and other nanostructured devices produced at ever-decreasing length scales, the extension of liquid-phase processes for the manufacturing of these devices is uncertain. The current work investigates the ability of liquids to wet nanoscale features. A model for wetting time is derived that may be used to identify those geometries for which wetting is critical. Conditions under which wetting time is significant may result in low yield and poor uniformity and may require alternate-phase processing. Furthermore, the dependence of wetting time on the properties of the fluid are quantified so that fluids may be designed to have optimal properties and thus optimal performance. The resulting model can be used as a tool to predict future processing requirements, and when necessary, to design novel processes implementing alternative phase fluids ͑e.g., vapor, subcritical, and supercritical fluids͒.

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Liquid‐Phase Processing of Hydrophilic Features on a Silicon Wafer

Cited by 14 publications

References 0 publications

Observation of liquid infiltration process into closed-end holes by droplet train impingement

Observation of liquid infiltration process into closed-end holes by droplet train impingement

Removing Gas from a Closed-End Small Hole by Irradiating Acoustic Waves with Two Frequencies

Incomplete Wetting of Nanoscale Thin-Film Structures

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