Vapor-Phase Self-Assembled Monolayers for Anti-Stiction Applications in MEMS

Zhuang, Yan; Hansen, Ole; Knieling, Thomas; Wang, C.; Rombach, Pirmin; Lang, Walter; Benecke, W.; Kehlenbeck, M.; Koblitz, Jörn

doi:10.1109/jmems.2007.904342

Cited by 81 publications

(59 citation statements)

References 36 publications

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“…This lubrication occurs not only at the nano-scale; it is also observed at the macro-scale where the surface roughness is several orders of magnitude larger than the size of adsorbed molecules [3]. Vapor can also be used to deliver a thin molecular coating to protect surfaces from wear [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Boundary lubrication effect of organic residue left on surface after evaporation of organic cleaning solvent

Barthel

Luo

Hwang

et al. 2016

Wear

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Although samples are visibly clean, organic deposits could have tremendous impacts on tribological measurements and interpretation of friction and wear behaviors. This paper discusses the boundary lubrication effects of invisible residues from organic solvents that have been widely used in tribological studies in ambient conditions. Stainless steel, soda lime glass, and copper substrates were cleaned using UV/ozone treatment or organic solvents such as alcohols where the solvent was allowed to evaporate from the surface. In ball-on-flat tribo-tests, all UV/ozone cleaned samples showed high friction and catastrophic wear immediately upon sliding due to the absence of lubricants at the sliding interface, while samples cleaned by organic solvent experienced low friction and minimal wear for hundreds of reciprocating cycles. Analyses of the surface by atomic force microscopy and vibrational spectroscopy indicated that the solvent cleaning deposits hydrocarbon residue on metal and oxide substrates. This residue is due to trace impurities with low vapor pressures inevitably present in the bulk liquid, regardless of solvent

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Section: Introductionmentioning

confidence: 99%

Boundary lubrication effect of organic residue left on surface after evaporation of organic cleaning solvent

Barthel

Luo

Hwang

et al. 2016

Wear

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“…Water vapor in the deposition chamber can induce the polymerization of silane molecules. 28,29 Due to this polymerization, aggregations may form and induce poor thermal stability of hydrophobic film. 28,29 As a result, a lower base pressure of 0.5 Torr was maintained to avoid aggregation of the precursor.…”

Section: Resultsmentioning

confidence: 99%

“…28,29 Due to this polymerization, aggregations may form and induce poor thermal stability of hydrophobic film. 28,29 As a result, a lower base pressure of 0.5 Torr was maintained to avoid aggregation of the precursor. Figure 3 shows the surface energy, contact angle, and contact angle hysteresis on vapor SAM coated Ni surfaces as functions of chamber temperature at a base pressure of 0.5 Torr.…”

Section: Resultsmentioning

confidence: 99%

Hydrophobic Modification of Diamond Conditioner for Prevention of Particle Adhesion During Oxide CMP

In-Kwon¹,

Kwon²,

Kim³

et al. 2011

J. Electrochem. Soc.

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Conditioning with a diamond conditioner is a routine practice in the chemical mechanical planarization process to maintain removal rate and uniformity. Electroplated Ni conditioner surfaces can be easily contaminated by polishing residues from the slurry, pad, and by-products during conditioning. In this study, a hydrophobic film was coated onto a Ni conditioner by vapor phase self assembled monolayer (V-SAM) deposition to prevent contamination. The film was deposited in a vacuum chamber at 0.5 Torr and 100 C using a fluorocarbon (FC) precursor. The modification of the Ni surfaces increased the contact angle from 50 to 105 . The adhesion force between the Ni surface and silica particles was approximately 100 nN in a solution of pH 11.2. The precursor coated Ni resulted in a five times lower adhesion force than the uncoated Ni conditioner. The coated conditioner did not attract any slurry residues on its surface, even after conditioning for 20 h with a fumed silica oxide slurry.Chemical mechanical planarization (CMP) consumables such as slurries, pads, conditioners and retainer rings have been adapted to achieve the required planarization of surfaces in semiconductor manufacturing. The surface asperity and porosity of CMP pads can greatly affect the material removal rate (MRR) and planarity during the polishing process. 1,2 However, the surfaces of the pads can undergo plastic deformation, so that the surface becomes smoother and the pores are filled with polishing residue, referred to as the 'glazing' effect. 3,4 Therefore, pad conditioning is necessary to maintain uniform MRR during CMP. 5 Ni conditioners with diamond particles are often heavily contaminated with slurry residues after conditioning. Once trapped in the conditioner surface, the residues remain and become harden, which reduces the conditioner life-time and causes the generation of unwanted particles from conditioner surfaces during polishing. These changes may generate scratches on oxide surfaces.The modification of surfaces with hydrophobic fluorocarbon films reduces the friction and stiction of two moving parts due to low surface energy and low friction coefficient characteristics. 5-9 A few methods are available for the preparation of hydrophobic films: self assembled monolayers (SAMs) and plasma polymerization. SAMs can be formed spontaneously on substrates from either liquid or vapor media. 10 Even though liquid SAMs are very simple to apply, it is difficult to control the process, which may therefore result in poor film quality and produce a large volume of waste. 11,12 Furthermore, liquid SAMs have limitations when coating nano or high-aspect-ratio structures due to high surface tension. 13 Vapor SAMs can be used in a vacuum by supplying a precursor in gas phase to a high temperature chamber. This method is easy to control and can be used to deposit multiple samples simultaneously. 13,14 Additionally, with the reaction of plasma and a precursor, the polymer can be polymerized and coated on the substrate at a desired deposition rate, which is...

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“…In this paper, we present a simple surface treatment process to allow moulding of PDMS against a PDMS master involving vapour phase deposition of 1H,1H,2H,2Hperfluorodecyltrichlorosilane (FDTS) onto the PDMS surface to reduce adhesive interaction. A similar approach for silicon substrates or SU-8 moulds has previously been reported to provide excellent anti-stiction surfaces to improve the release of structures [19][20][21]. But, to our knowledge, there have been no previous reports on vapour deposition of FDTS on PDMS to promote anti-stiction.…”

Section: Introductionmentioning

confidence: 87%

Anti-stiction coating of PDMS moulds for rapid microchannel fabrication by double replica moulding

Zhuang¹,

Kutter²

2011

J. Micromech. Microeng.

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In this paper, we report a simple and precise method to rapidly replicate master structures for fast microchannel fabrication by double replica moulding of polydimethylsiloxane (PDMS). A PDMS mould was surface-treated by vapour phase deposition of 1H,1H,2H,2Hperfluorodecyltrichlorosilane (FDTS), which resulted in an anti-stiction layer for the improved release after PDMS casting. The deposition of FDTS on an O 2 plasma-activated surface of PDMS produced a reproducible and well-performing anti-stiction monolayer of fluorocarbon, and we used the FDTS-coated moulds as micro-masters for rapid replication of micro-structures, avoiding the necessity to have to use other, more costly and fragile master materials. Our protocol has been shown to reliably fabricate PDMS-based microfluidic devices in a low-cost and efficient manner. The replicas were further employed as micro-contract stamps to fabricate polymer-based waveguides.

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Vapor-Phase Self-Assembled Monolayers for Anti-Stiction Applications in MEMS

Cited by 81 publications

References 36 publications

Boundary lubrication effect of organic residue left on surface after evaporation of organic cleaning solvent

Boundary lubrication effect of organic residue left on surface after evaporation of organic cleaning solvent

Hydrophobic Modification of Diamond Conditioner for Prevention of Particle Adhesion During Oxide CMP

Anti-stiction coating of PDMS moulds for rapid microchannel fabrication by double replica moulding

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