Controlled Undercutting of V‐Groove Channels for InP by Photoresist Etch Mask

Huo, Da; Wynn, J. D.; Napholtz, S. G.; Wilt, D. P.

doi:10.1149/1.2095935

Cited by 12 publications

(9 citation statements)

References 10 publications

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“…This can come about due to changed properties of the etched material induced by the mask material in close vicinity under the mask [30] or due to the formation of a layer (e.g. oxide) at the interface [31,32]. These phenomena usually lead to increased undercutting, which directly influences the formation of wet-etched objects.…”

Section: Discussionmentioning

confidence: 99%

Wet-etch bulk micromachining of (100) InP substrates

Eliáš

Kostič

Šoltýs

et al. 2004

J. Micromech. Microeng.

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The study focused on object formation in (100) InP by etching in 3HCl:1H3PO4 through convex and concave square mask patterns of varied orientation and size. Their upper right-hand-side corners were aligned to , and to 15°, 30° and 45° off to . Some -oriented convex squares had - and -oriented corners compensated with rectangular extensions. The concave patterns led to objects with ordinary slow-etching or etch-stop facets along sides in line within and with ordinary and re-entrant facets along sides in line within . The convex patterns (, 15° and 30°) led to objects initially confined by fast-etching facets at corners and slow-etching or etch-stop facets at sides (ordinary between and , and re-entrant between and ). The side facets were eliminated by the progress of the corner ones. They (-oriented patterns) proceeded at rates almost independent of size before the eradication of the side facets, after which they proceeded faster. The -oriented convex patterns led to objects confined only by fast-etching facets. The objects developed at rates that considerably depended on pattern size and etching time. Objects under small patterns developed faster compared to those under large ones. The -oriented corner-compensated patterns led to pyramidal objects confined by facets related to (110), , (101) and .

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Section: Discussionmentioning

confidence: 99%

Wet-etch bulk micromachining of (100) InP substrates

Eliáš

Kostič

Šoltýs

et al. 2004

J. Micromech. Microeng.

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“…The results described in this paper are applicable to the initial processing of semiconductor cathodes for vacuum microelectronics devices (1)(2)(3) and to controlling the blaze angle for optical diffraction gratings (4,5). Each of these applications require control of the sidewall angle Os as shown in Fig.…”

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confidence: 91%

Reactive Ion Etching Techniques for Silicon Sidewall Angle Control in Microengineering

Kim

Carr

Zeto

et al. 1992

J. Electrochem. Soc.

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This paper describes reactive ion etching (RIE) techniques with silicon substrates for initial processing of semiconductor field emitter array cathodes for vacuum microelectronics. A secondary focus is process research for optical reflecting gratings for opto-and micromechanical devices. These applications each require control of the sidewall angle and apex radius. In this paper, we describe micromachining control of trenches with remainder sidewall angles varying from 15-60 ~ and resulting apex ridge radii of as small as 40 nm. A fluorine-based chemistry (CF4/O2) with oblique angles for the incident beam (tilted substrates) and overetching is used. The use of both deep UV-hardened photoresist and aluminum as RIE shadowmasks is compared. Unannealed aluminum as a shadowmask for RIE micromachining has the advantage of lower etch/sputtering rates and higher process temperature tolerance compared to photoresist in the CF402 RIE system. Etch environments in the pressure range 30-80 mTorr with CF4/O2 flow rates of 20/2 sccm, RF power 100-200 W, and etch duration 30 min are described. Both tilted and untilted substrates mountings were studied. Under these conditions, the surface erosion is primarily a combination of ion milling and chemical etch mechanisms. Both P-type and N-type substrates of 100 nm diam wafers were used. Relatively sharp single-and double-ridged silicon structures were obtained using the photoresist shadowmask on untilted substrates. The photoresist shadowmask provides an advantage over A1 only for the sidewall orientation 0 t : 20 ~ where we were able to specify a condition for obtaining a smooth optically reflective surface. The more vertical sidewall angles obtainable with the unannealed A1 shadowmask should permit fabrication of field emitter cone or ridge cathodes on pedestals with higher height-to-width ratios. A field cathode pedestal with a more vertical sidewall results in a higher electric field at the electron emission tip or ridge.

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“…These failures can be caused by defects present in the superstructure (oxide, poly, or metal) (i, 2) or by crystallographic defects present in the silicon substrate (i-4). The generation process of crystallographic defects is a complex function of processing conditions and silicon substrate characteristics (5)(6)(7)(8)(9)(10)(11)(12). Heavy metals present in a processing line can influence the crystallographic defect generation process by providing nucleation sides for the generation of stacking faults (8).…”

Section: Introductionmentioning

confidence: 99%

“…As-received wafers were cleaned by conventional chloroform-acetone-methanol (CAM) solvents, rinsed in distilled water, dried with high purity nitrogen, etched in HF to remove native oxide, and blown dry with high purity nitrogen. In this experiment, two etch masks were used: a) photoresist etch mask (8,9), and b) SiO2 etch mask (10). Windows of the etch masks were aligned along <110> and <110> directions and etched in 5:1 HCI:H~PO4 and BPK-221 (HBr:HzPO4:-K2Cr2OT) etchants, respectively.…”

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confidence: 99%

Effects of Mask Imperfections on InP Etching Profiles

Huo¹,

Yan²,

Wynn³

et al. 1990

J. Electrochem. Soc.

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We have demonstrated that the quality of etch masks has a significant effect on the InP etching profiles. In particular, we have shown that mask imperfections can cause defective etching profiles, such as vertical sidewalls and extra mask undercutting in InP. We also discovered that the geometry of these defective profiles is determined by the orientation of the substrate relative to the direction of the mask imperfections. Along a < 110> line mask defect, the downward etching_process changes the < 110> v-grooves to vertical sidewalls without extra undercutting. For v-grooves aligned along the < 110> direction, defects on the mask give a significant extra undercutting without changing the etching profile.

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Controlled Undercutting of V‐Groove Channels for InP by Photoresist Etch Mask

Cited by 12 publications

References 10 publications

Wet-etch bulk micromachining of (100) InP substrates

Wet-etch bulk micromachining of (100) InP substrates

Reactive Ion Etching Techniques for Silicon Sidewall Angle Control in Microengineering

Effects of Mask Imperfections on InP Etching Profiles

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