Polymer thickness effects on Bosch etch profiles

Craigie, C. J.; Sheehan, Therese; Johnson, V.N.; Burkett, S. L.; Moll, Amy; Knowlton, William B.

doi:10.1116/1.1515910

Cited by 48 publications

(40 citation statements)

References 5 publications

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“…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

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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%

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

“…Although not pursued in the current study, profile control with further precision may be possible by fine tuning the etch parameters and consulting the relevant literature. [54][55][56][57][58][59] Figures 4(a) and 4(b) show etched large square fields (p ¼ 5 lm, s ¼ 7 lm) before and after removal of the sacrificial structures, respectively. The sacrificial structures partially collapsed during the wafer cleaning and SiO 2 etching after DRIE, but were completely removed from the wafer surface and structures.…”

Section: Resultsmentioning

confidence: 99%

Sacrificial structures for deep reactive ion etching of high-aspect ratio kinoform silicon x-ray lenses

Stöhr

Michael-Lindhard

Hübner

et al. 2015

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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O. (2015). Sacrificial structures for deep reactive ion etching of high-aspect ratio kinoform silicon x-ray lenses. Journal of Vacuum Science and Technology. Part B. Microelectronics and Nanometer Structures, 33(6), [062001]. DOI: 10.1116/1.4931622 Sacrificial structures for deep reactive ion etching of high-aspect ratio kinoform silicon x-ray lenses This article describes the realization of complex high-aspect ratio silicon structures with feature dimensions from 100 lm to 100 nm by deep reactive ion etching using the Bosch process. As the exact shape of the sidewall profiles can be crucial for the proper functioning of a device, the authors investigated how sacrificial structures in the form of guarding walls and pillars may be utilized to facilitate accurate control of the etch profile. Unlike other sacrificial structuring approaches, no silicon-on-insulator substrates or multiple lithography steps are required. In addition, the safe removal of the sacrificial structures was accomplished by thermal oxidation and subsequent selective wet etching. The effects of the dimensions and relative placement of sacrificial walls and pillars on the etching result were determined through systematic experiments. The authors applied this process for exact sidewall control in the manufacture of x-ray lenses that are very sensitive to sidewall shape nonuniformities. Compound kinoform lenses for focusing hard x-rays with structure heights of 200 lm were manufactured, and the lenses were tested in terms of their focusing ability and refracting qualities using synchrotron radiation at a photon energy of 17 keV. A 180 lm long line focus with a waist of 430 nm at a focal length of 215 mm was obtained.

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“…Step 2-Etch Via Through Wafer: An inductively-coupled plasma etcher utilizing the Bosch process [22] is used to etch an anisotropic hole through the entire thickness of the silicon wafer. The Bosch process consists of a short etch step, utilizing , followed by a sidewall passivation step utilizing .…”

Section: Fabrication Process Stepsmentioning

confidence: 99%

Integrating Through-Wafer Interconnects With Active Devices and Circuits

Jozwiak

Southwick

Johnson

et al. 2008

IEEE Trans. Adv. Packag.

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Abstract-Through wafer interconnects (TWIs) enable vertical stacking of integrated circuit chips in a single package. A complete process to fabricate TWIs has been developed and demonstrated using blank test wafers. The next step in integrating this technology into 3-D microelectronic packaging is the demonstration of TWIs on wafers with preexisting microcircuitry. The circuitry must be electrically accessible from the backside of the wafer utilizing the TWIs; the electrical performance of the circuitry must be unchanged as a result of the TWI processing; and the processing must be as cost effective as possible. With these three goals in mind, several options for creating TWIs were considered. This paper explores the various processing options and describes in detail, the final process flow that was selected for testing, the accompanying masks that were designed, the actual processing of the wafers, and the electrical test results.

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Polymer thickness effects on Bosch etch profiles

Cited by 48 publications

References 5 publications

A nontransferring dry adhesive with hierarchical polymer nanohairs

A nontransferring dry adhesive with hierarchical polymer nanohairs

Sacrificial structures for deep reactive ion etching of high-aspect ratio kinoform silicon x-ray lenses

Integrating Through-Wafer Interconnects With Active Devices and Circuits

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