Focused ion beam irradiation: morphological and chemical evolution in epoxy polymers

Kochumalayil, Joby J.; Meiser, Andreas; Soldera, F.; Possart, Wulff

doi:10.1002/sia.3121

Cited by 6 publications

(3 citation statements)

References 19 publications

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“…Poly(styrene) therefore tends to cross‐link after exposure to radiation. It has been shown that the introduction of water vapor during Ga + ion bombardment of PS maintains a high sputtering rate, presumably due to the reaction of water with radical species and the prevention of cross‐linking …”

Section: Resultsmentioning

confidence: 99%

Argon cluster cleaning of Ga⁺ FIB‐milled sections of organic and hybrid materials

Tiddia

Seah

Shard

et al. 2018

Surface & Interface Analysis

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Secondary ion mass spectrometry studies have been made of the removal of the degraded layer formed on polymeric materials when cleaning focused ion beam (FIB)-sectioned samples comprising both organic and inorganic materials with a 30-keV Ga + FIB. The degraded layer requires a higher-than-expected Ar gas cluster ion beam (GCIB) dose for its removal, and it is shown that this arises from a significant reduction in the layer sputtering yield compared with that for the undamaged polymer. Stopping and Range of Ions in Matter calculations for many FIB angles of incidence on flat polymer surfaces show the depth of the damage and of the implantation of the Ga + ions, and these are compared with the measured depth profiles for Ga + -implanted flat polymer surfaces at several angles of incidence using an Ar + GCIB. The Stopping and Range of Ions in Matter depth and the measured dose give the sputtering yield volume for this damaged and Ga +implanted layer. These, and literature yield values for Ga + damaged layers, are combined on a plot showing how the changing sputtering yield is related to the implanted Ga density for several polymer materials. This plot contains data from both the model flat poly(styrene) surfaces and FIB-milled sections showing that these 2 surfaces have the same yield reduction. The results show that the damaged and Ga + -implanted layer's sputtering rate,after FIB sectioning, is 50 to 100 times lower than for undamaged polymers and that it is this reduction in sputtering rate, rather than any development of microtopography, that causes the high Ar + GCIB dose required for cleaning these organic surfaces.

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Section: Resultsmentioning

confidence: 99%

Argon cluster cleaning of Ga⁺ FIB‐milled sections of organic and hybrid materials

Tiddia

Seah

Shard

et al. 2018

Surface & Interface Analysis

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“…Possible routes to minimize the damage caused by the ion beam include milling the polymers at cryogenic temperatures (e.g. −150°C) to reduce local heating (Niihara et al ., 2005; Sezen et al ., 2009; Kim et al ., 2011; Sezen et al ., 2011), applying an electrically conductive coating or using an electron flood gun against ion charging (Stokes et al ., 2007) or removing the polymer at a faster rate using water vapour (Kochumalayil et al ., 2009a, b).…”

Section: Introductionmentioning

confidence: 99%

Three‐dimensional nanofabrication of polystyrene by focused ion beam

Lee

Proust

Alici

et al. 2012

Journal of Microscopy

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SummaryFocused ion beam micromachining provides a maskless and resistless technique for prototyping of structures from thermoplastic polymers, an example being the production of polystyrene microcantilevers with potential applications as micro/nanoelectromechanical systems sensors and actuators. The applicability of FIB technology is, however, often restricted by the damage created by high energy gallium ion bombardment and local beam heating, which can affect the desired properties and limit the minimum achievable size of the fabricated structure. To investigate the ion-induced damage and determine the limitations of the technique for polymer nanofabrication, we have exposed thin polystyrene film to the ion beam at varying ion doses, ion energies and specimen temperatures. Ion doses ranging from 10 16 to 10 18 ions cm −2 show significant gallium implantation, redeposition of sputtered material and chemical degradation in the polymer. Raman results show that the local heating in polymer during milling is severe at room temperature, damaging the aromatic carbon bonding (C = C) in particular. These observations are supported by the results of a beam heating model and Monte Carlo simulations. The chemical degradation caused by local beam heating is found to be significantly reduced by cooling the specimen to −25 • C during milling. This is consistent with observations that reversible and repeatable thermal actuation of a fabricated polystyrene-platinum microcantilever is only observed when the cantilever is prepared at low temperature milling. Using this cooling approach, polymer structures can be fabricated with dimensions as low as 200 nm and still retain a sufficient volume of material unaffected by the ion beam.

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“…While the utility of FIB nanomachining and ISE imaging was demonstrated for two specific bicomponent polymer systems, harnessing the full potential of nanomachining and differential sputtering to reveal morphology hinges on the ability to optimize FIB sputtering conditions for different polymeric systems. Sputtering of polymers is likely a complex process dependent on both the polymer's properties and FIB beam parameters [2,3]. Of all the polymer properties, crystallinity influences many of the polymer mechanical properties such as hardness.…”

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confidence: 99%

The Effect of Crystallinity on Materials Removal Rate of Polyolefins During Ga⁺ Focused Ion Beam Nanomachining

et al. 2011

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The development of optimized focused ion beam (FIB) nanomachining methodologies is essential to the advancement of FIB for characterization polymeric materials. The ability to examine the topographical and morphological properties of polymeric materials can provide significant insight into their functional properties. Recently, a FIB in situ technique was developed for revealing and imaging the cross sectional morphology of the polymeric components in a bicomponent polymeric fiber with the island-in-the-sea (I/S) structure [1]. This technique exploits the topographical contrast generated as a result of differential sputtering. When combined with the high surface specificity and high signal-to-noise ratio obtained using Ga + FIB induced secondary electron (ISE) imaging, the capability of FIB technology to provide a useful approach for efficient characterization of the cross-sectional morphology of bicomponent polymeric fibers was demonstrated without any sample pretreatment. While the utility of FIB nanomachining and ISE imaging was demonstrated for two specific bicomponent polymer systems, harnessing the full potential of nanomachining and differential sputtering to reveal morphology hinges on the ability to optimize FIB sputtering conditions for different polymeric systems. Sputtering of polymers is likely a complex process dependent on both the polymer's properties and FIB beam parameters [2,3]. Of all the polymer properties, crystallinity influences many of the polymer mechanical properties such as hardness. To gain a better understanding of the process of the nanomachining of polymers, the fundamental relationships between material removal rate and dose for polymers having different cystallinities were investigated.Two technologically important polyolefins, linear low density polyethylene (LLDPE; Dow Chemical Company, USA) and isotactic polypropylene (PP; Product CP360H, Sunoco Chemicals Polymers Division, USA), were investigated in this study. Polymer beads of LLDPE and PP were melted at 140 o C and 180 o C, respectively, in an oven (Model 280A, Fisher Scientific, USA) under argon gas flow. Polymers beads were melted between two pieces of Si to form the polymer into a film having a smooth surface. The polymer melt films were then quenched in a commercial freezer to -15 o C. Subsequent thermal annealing of each polymer was carried out at 115 o C and 125 o C for LLDPE and PP, respectively, for different time intervals to produce different levels of crystallinity. The crystallinity of the annealed polymer samples was measured using a SmartLab x-ray diffractometer (XRD) and quantified with the SmartLab Guidance software (Rigaku Americas, USA). A Quanta 200 3D DualBeam FIB/SEM system (FEI Company, USA) with a 30kV Ga + beam was used for all sputtering experiments. To determine the material removal rate for each polymer sample, 5µm x 5µm and 10µm x 10µm craters were sputtered into the respective polymer films under various experimental conditions. Craters were sputtered by scanning the Ga + beam in a serpentine p...

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Focused ion beam irradiation: morphological and chemical evolution in epoxy polymers

Cited by 6 publications

References 19 publications

Argon cluster cleaning of Ga⁺ FIB‐milled sections of organic and hybrid materials

Argon cluster cleaning of Ga⁺ FIB‐milled sections of organic and hybrid materials

Three‐dimensional nanofabrication of polystyrene by focused ion beam

The Effect of Crystallinity on Materials Removal Rate of Polyolefins During Ga⁺ Focused Ion Beam Nanomachining

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Focused ion beam irradiation: morphological and chemical evolution in epoxy polymers

Cited by 6 publications

References 19 publications

Argon cluster cleaning of Ga+ FIB‐milled sections of organic and hybrid materials

Argon cluster cleaning of Ga+ FIB‐milled sections of organic and hybrid materials

Three‐dimensional nanofabrication of polystyrene by focused ion beam

The Effect of Crystallinity on Materials Removal Rate of Polyolefins During Ga+ Focused Ion Beam Nanomachining

Contact Info

Product

Resources

About

Argon cluster cleaning of Ga⁺ FIB‐milled sections of organic and hybrid materials

Argon cluster cleaning of Ga⁺ FIB‐milled sections of organic and hybrid materials

The Effect of Crystallinity on Materials Removal Rate of Polyolefins During Ga⁺ Focused Ion Beam Nanomachining