A new approach to convex corner compensation for anisotropic etching of (100) Si in KOH

Zhang, Qingxin; Liu, Litian; Z, Li

doi:10.1016/s0924-4247(96)01312-x

Cited by 55 publications

(43 citation statements)

References 3 publications

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“…triangle, square, <110> −beam) provides sharp edge convex corner. In continuation of the efforts to fabricate sharp convex corner, a simple <100> oriented beam is proposed as presented in Figure 30 [92,100,103,105,108,109,120,122,125]. As shown by dotted lines, the beam is consumed by Figure 24 Sequentially etched shape for a mesa structure with triangular shape compensating design in surfactant added 25 wt% TMAH [120].…”

Section: Corner Compensation Geometries For Si{100} Wafermentioning

confidence: 99%

A comprehensive review on convex and concave corners in silicon bulk micromachining based on anisotropic wet chemical etching

Pal

Sato

2015

Micro and Nano Syst Lett

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Section: Corner Compensation Geometries For Si{100} Wafermentioning

confidence: 99%

A comprehensive review on convex and concave corners in silicon bulk micromachining based on anisotropic wet chemical etching

Pal

Sato

2015

Micro and Nano Syst Lett

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“…When exposed to a KOH solution, they undergo undesirable opportunistic etching in an unconventional nature. Unlike the more uniform <111> defined slope of the <110> adjacent micro ridge wall, etching these convex corners forms random surfaces that cause severe damage to these corners in extreme cases (Enoksson et al 1997;Mayer et al 1990;Offereins et al 1991;Puers and Sansen 1990;Schroder et al 2001;Schroder and Obermeier 2000;Zhang et al 1996). The study further elucidate that microridges oriented further away from the <110> plane experience exacerbated structural anhilation compared to those oriented along the latter plane.…”

Section: Introductionmentioning

confidence: 74%

Pattern induced convex corner undercutting of oriented silicon microridges in potassium hydroxide

2015

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Section: (Iii) <110> Oriented Beammentioning

confidence: 99%

A comprehensive review on convex and concave corners in silicon bulk micromachining based on anisotropic wet chemical etching

Pal¹,

Sato²

2016

Nano Online

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Wet anisotropic etching based silicon micromachining is an important technique to fabricate freestanding (e.g. cantilever) and fixed (e.g. cavity) structures on different orientation silicon wafers for various applications in microelectromechanical systems (MEMS). {111} planes are the slowest etch rate plane in all kinds of anisotropic etchants and therefore, a prolonged etching always leads to the appearance of {111} facets at the sidewalls of the fabricated structures. In wet anisotropic etching, undercutting occurs at the extruded corners and the curved edges of the mask patterns on the wafer surface. The rate of undercutting depends upon the type of etchant and the shape of mask edges and corners. Furthermore, the undercutting takes place at the straight edges if they do not contain {111} planes. {100} and {110} silicon wafers are most widely used in MEMS as well as microelectronics fabrication. This paper reviews the fabrication techniques of convex corner on {100} and {110} silicon wafers using anisotropic wet chemical etching. Fabrication methods are classified mainly into two major categories: corner compensation method and two-steps etching technique . In corner compensation method, extra mask pattern is added at the corner. Due to extra geometry, etching is delayed at the convex corner and hence the technique relies on time delayed etching. The shape and size of the compensating design strongly depends on the type of etchant, etching depth and the orientation of wafer surface. In this paper, various kinds of compensating designs published so far are discussed. Two-step etching method is employed for the fabrication of perfect convex corners. Since the perfectly sharp convex corner is formed by the intersection of {111} planes, each step of etching defines one of the facets of convex corners. In this method, two different ways are employed to perform the etching process and therefore can be subdivided into two parts. In one case, lithography step is performed after the first step of etching, while in the second case, all lithography steps are carried out before the etching process, but local oxidation of silicon (LOCOS) process is done after the first step of etching. The pros and cons of all techniques are discussed.

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A new approach to convex corner compensation for anisotropic etching of (100) Si in KOH

Cited by 55 publications

References 3 publications

A comprehensive review on convex and concave corners in silicon bulk micromachining based on anisotropic wet chemical etching

A comprehensive review on convex and concave corners in silicon bulk micromachining based on anisotropic wet chemical etching

Pattern induced convex corner undercutting of oriented silicon microridges in potassium hydroxide

A comprehensive review on convex and concave corners in silicon bulk micromachining based on anisotropic wet chemical etching

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