High aspect ratio Bosch etching of sub-0.25μm trenches for hyperintegration applications

Wang, Xiaodong; Zeng, Wanxue; Lu, Guo‐ping; Russo, Onofrio; Eisenbraun, Eric

doi:10.1116/1.2756554

Cited by 32 publications

(25 citation statements)

References 13 publications

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“…In the present study, this problem has been resolved by using a plasma etcher, in which a Faraday cage was installed as an auxiliary device in the conventional gas chopping process (or the Bosch process). The conventional gas chopping process has been widely used in microelectromechanical systems (MEMS), providing high-AR Si etch profiles on a nanometer scale (23,24). However, this etching process is limited in controlling the angle of the etch profile as shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

A nontransferring dry adhesive with hierarchical polymer nanohairs

Jeong¹,

Lee

Kim³

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

510

527

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We present a simple yet robust method for fabricating angled, hierarchically patterned high-aspect-ratio polymer nanohairs to generate directionally sensitive dry adhesives. The slanted polymeric nanostructures were molded from an etched polySi substrate containing slanted nanoholes. An angled etching technique was developed to fabricate slanted nanoholes with flat tips by inserting an etch-stop layer of silicon dioxide. This unique etching method was equipped with a Faraday cage system to control the ionincident angles in the conventional plasma etching system. The polymeric nanohairs were fabricated with tailored leaning angles, sizes, tip shapes, and hierarchical structures. As a result of controlled leaning angle and bulged flat top of the nanohairs, the replicated, slanted nanohairs showed excellent directional adhesion, exhibiting strong shear attachment (Ϸ26 N/cm 2 in maximum) in the angled direction and easy detachment (Ϸ2.2 N/cm 2 ) in the opposite direction, with a hysteresis value of Ϸ10. In addition to single scale nanohairs, monolithic, micro-nanoscale combined hierarchical hairs were also fabricated by using a 2-step UV-assisted molding technique. These hierarchical nanoscale patterns maintained their adhesive force even on a rough surface (roughness <20 m) because of an increase in the contact area by the enhanced height of hierarchy, whereas simple nanohairs lost their adhesion strength. To demonstrate the potential applications of the adhesive patch, the dry adhesive was used to transport a large-area glass (47.5 ؋ 37.5 cm 2 , second-generation TFT-LCD glass), which could replace the current electrostatic transport/ holding system with further optimization.biomimetics ͉ gecko ͉ angled etching ͉ slanted nanohair ͉ hierarchical nanohair A dhesive are used in many aspects of the daily life. With increasing demands for various applications in the industry, new adhesives have been developed that use thermoplastic, UV or light curing, rubbery and pressure-sensitive materials (1). In general, such man-made adhesives have high (sometimes extremely strong) adhesion strength but are not easily detached. Furthermore, they are seldom reusable because the surfaces are quickly contaminated by adhering materials because of their tacky nature. In contrast, nature has created its own adhesives with unique structures and functions. For example, mussels generate specialized adhesive proteins, allowing for strong adhesion to wet surfaces, which is not easily achievable with man-made adhesives (2).In addition, dry adhesion mechanism in gecko lizards has attracted much attention because it provides strong, yet reversible attachment against surfaces of varying roughness and orientation. Such unusual adhesion capability is attributed to arrays of millions of fine microscopic foot hairs (setae), splitting into hundreds of smaller, nanoscale ends (spatulae), which form intimate contact to various surfaces by van der Waals forces with strong adhesion (Ϸ10

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Section: Resultsmentioning

confidence: 99%

“…The other was to use an etch-stop layer to improve the adhesive force of replicated structures. Because the gas chopping process makes the bottom etch profile round shaped (24,29) (Fig. 1D), the contact fraction of nanohairs replicated from the master was reduced at the time of contact (13).…”

Section: Resultsmentioning

confidence: 99%

A nontransferring dry adhesive with hierarchical polymer nanohairs

Jeong¹,

Lee

Kim³

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

510

527

View full text Add to dashboard Cite

show abstract

“…The flow channel had an inlet at one side and a 50-µm-wide serpentine ending with an outlet at the other side. The silicon wafer was patterned using standard lithography techniques (Photoresists S1818, AZ4562 MicroChem) and etched using reactive ion etching in an ICP-RIE (Surface Technology Systems) using the Bosch process 32 for deep features (>5 µm). The compartment and flow channel were etched in two separate steps.…”

Section: Letters Nature Physics Doi: 101038/nphys3469mentioning

confidence: 99%

Propagating gene expression fronts in a one-dimensional coupled system of artificial cells

et al. 2015

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Living systems employ front propagation and spatiotemporal patterns encoded in biochemical reactions for communication, self-organization and computation 1-4 . Emulating such dynamics in minimal systems is important for understanding physical principles in living cells [5][6][7][8] and in vitro 9-14 . Here, we report a one-dimensional array of DNA compartments in a silicon chip as a coupled system of artificial cells, o ering the means to implement reaction-di usion dynamics by integrated genetic circuits and chip geometry. Using a bistable circuit we programmed a front of protein synthesis propagating in the array as a cascade of signal amplification and short-range di usion. The front velocity is maximal at a saddle-node bifurcation from a bistable regime with travelling fronts to a monostable regime that is spatially homogeneous. Near the bifurcation the system exhibits large variability between compartments, providing a possible mechanism for population diversity. This demonstrates that on-chip integrated gene circuits are dynamical systems driving spatiotemporal patterns, cellular variability and symmetry breaking.Sharp travelling fronts are prevalent in nature and emerge when nonlinear and dispersive effects combine, for example solitary waves in nonlinear optics, fluid convection, and chemical reactions 15 . Biological multicellular systems use travelling fronts of molecular signals as a means for computation and communication over long distances when signalling by diffusion is inefficient. In these systems, cells can be described as autocatalytic units that amplify and transmit signals beyond a threshold. Because signals dissipate in the medium over short distances, long-range information transmission is achieved by consecutive local cell-cell interactions. Signal propagation has been measured over orders of magnitudes in a variety of biological processes, ranging from fast action potentials in neuron networks with typical velocities 16 of v ≈ 10 7 mm h −1 , to slow gene expression fronts in development 3 with v ≈ 0.1 mm h −1 . Although some systems have a linearly unstable initial state, and thus can be treated as Fisher waves 17 , the majority of biological examples require more complex models, including the cable equation and Hodgkin-Huxley model 18 . These systems raise questions concerning the selected speed, bifurcations, fluctuations and stability in parameter space 15 , which are challenging to study in a living organism.Front propagation has been extensively studied in chemical reactions 16,19 and more recently in reconstituted biological systems, including the bacterial cell division network 10 , the Xenopus laevis cell cycle 11 , and RNA (ref. 20) and DNA (ref. 14) catalytic reactions. In the past decade cell-free transcription-translation reactions have been used to advance the design of programmable artificial gene systems, including bulk solution 21 , gels 9 , membrane vesicles 22 , water-in-oil drops 23 , microfluidic devices 24 and on-chip DNA compartments 13 . So far, however, a synthet...

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“…To enhance anisotropic etching, inductive coupled plasma reactive ion etching (ICP) and the Bosch process were developed. A number of groups have reported silicon deep structures with feature sizes ranging from 200 nm to microns that were realized using ICP and the Bosch process [3][4][5][6][7] . The disadvantage of this process, however, is that after etching, the sidewall roughness of the trench is unacceptable and its width is usually enlarged.…”

Section: Introductionmentioning

confidence: 99%

A process study of electron beam nano-lithography and deep etching with an ICP system

Zhang

Chen

et al. 2009

Sci. China Ser. E-Technol. Sci.

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A systemic process study on an electron beam nanolithography system operating at 100 kV was present. The exposure conditions were optimized for resist ZEP520A. Grating structures with line/space of 50 nm/50 nm were obtained in a reasonably thick resist which is beneficial to the subsequent pattern transfer technique. The ICP etching process conditions was optimized. The role of etching parameters such as source power, gas pressure, and gas flow rate on the etching result was also discussed. A grating structure with line widths as small as 100 nm, duty cycles of 0.5, depth of 900 nm, and the side-wall scalloping as small as 5 nm on a silicon substrate was obtained. The silicon deep etching technique for structure sizes smaller than 100 nm is very important for the fabrication of nano-optical devices working in the visible regime. electron beam lithography, ZEP520A resist, reactive ion etching, nanofabrication

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High aspect ratio Bosch etching of sub-0.25μm trenches for hyperintegration applications

Cited by 32 publications

References 13 publications

A nontransferring dry adhesive with hierarchical polymer nanohairs

A nontransferring dry adhesive with hierarchical polymer nanohairs

Propagating gene expression fronts in a one-dimensional coupled system of artificial cells

A process study of electron beam nano-lithography and deep etching with an ICP system

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