Deep lateral anhydrous HF/methanol etching for MEMS release processes

Erdamar, Meltem; Karthikeyan, S.; Roman, P.; Mumbauer, P.; Klimkiewicz, M.; Rużyłło, Jerzy

doi:10.1117/1.2959177

Cited by 9 publications

(6 citation statements)

References 5 publications

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“…This process allows the efficient release of microstructures by etching of a sacrificial oxide layer and without producing subsequent sticking of the released structures to the substrate [12]. As demonstrated by tests, all of the exposed materials except for the sacrificial oxide layer are resistant to this etchant.…”

Section: Wafer Level Vacuum Encapsulationmentioning

confidence: 95%

High-performance long wave infrared bolometer fabricated by wafer bonding

et al. 2010

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A novel microbolometer with peak responsivity in the longwave infrared region of the electromagnetic radiation is under development at Sensonor Technologies. It is a focal plane array of pixels with a 25µm pitch, based on monocrystalline Si/SiGe quantum wells as IR sensitive material. The novelty of the proposed 3D process integration comes from the choice of several of the materials and key processes involved, which allow a high fill factor and provide improved transmission/absorption properties. Together with the high TCR and low 1/f noise provided by the thermistor material, they will lead to bolometer performances beyond those of existing devices. The thermistor material is transferred from the handle wafer to the read-out integrated circuit (ROIC) by wafer bonding. The low thermal conductance legs that connect the thermistor to the ROIC are fabricated prior to the transfer bonding and are situated under the pixel. Depending on the type of the transfer bonding used, the plugs connecting the legs to the thermistor are made before or after this bonding, resulting in two different configurations of the final structure. Using a low temperature oxide bonding and subsequent plugs formation result in through-pixel plugs. Pre-bonding plugs formation followed by thermo-compression bonding result in under-pixel plugs. The pixels are subsequently released by anhydrous vapor HF of the sacrificial oxide layer. The ROIC wafer containing the released FPAs is bonded in vacuum with a silicon cap wafer, providing hermetic encapsulation at low cost. Antireflection coatings and a thin layer getter are deposited on the cap wafer prior to bonding, ensuring high performance of the bolometer.

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Section: Wafer Level Vacuum Encapsulationmentioning

confidence: 95%

High-performance long wave infrared bolometer fabricated by wafer bonding

et al. 2010

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“…Removal of possible etch residues from such extremely confined geometrical features and assuring stiction-free operation of beams and membranes cannot be accomplished using conventional wet cleaning and etching technology. The anhydrous HF/methanol (AHF/MeOH) [6] sacrificial oxide etch process has been investigated as a viable solution to the latter [7]. Solution to the MEMS clean-ing problems comes in the form of a supercritical fluid cleaning technology [8].…”

Section: Mems Technologymentioning

confidence: 99%

Semiconductor cleaning technology for next generation material systems

Ruzyllo

2007

JTIT

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This paper gives a brief overview of the challenges wafer cleaning technology is facing in the light of advanced silicon technology moving in the direction of non-planar device structures and the need for modified cleans for semiconductors other than silicon. In the former case, the key issue is related to cleaning and conditioning of vertical surfaces in next generation CMOS gate structure as well as deep 3D geometries in MEMS devices. In the latter, an accelerated pace at which semiconductors other than silicon are being introduced into the mainstream manufacturing calls for the development of material specific wafer cleaning technologies. Examples of the problems related to each challenge are considered.

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“…HF vapor etching has also been investigated in various ways. [30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45] For conformal etching, as discussed before, gas vapor etching would be the best option. In most vapor etchings, HF/H 2 O is used; however, there is concern about the corrosion of chamber parts by hydrofluoric acid.…”

Section: Introductionmentioning

confidence: 99%

Etching selectivity of SiO₂ to SiN using HF and methanol at higher pressures up to 900 Pa

Hattori,

Kobayashi,

Ohtake

et al. 2024

Jpn. J. Appl. Phys.

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The isotropic gas-phase etching of SiO2 was examined using HF and methanol vapor while changing the pressure from 300 Pa to 900 Pa. The temperature dependence of the etching rate of SiO2 showed a broad maximum around –30 °C, and the rate increased with increasing the pressure. The etching rate of plasma-enhanced chemical vapor deposition (PE-CVD) SiO2 became more than 60 nm/min at 900 Pa at –30 °C. When the pressure was increased from 300 Pa to 900 Pa, the temperature range that indicates the SiO2 etching was shifted to a higher temperature. The etching of SiO2, which did not proceed at 300 Pa, was found to proceed even at 0 °C at 900 Pa. The etching rate of PE-CVD SiN was also found to slightly increase with the pressure. At the higher pressure of 900 Pa, the formation of ammonium hexafluorosilicate, which is byproduct of SiN, was found to increase. As a result, the high selectivity of more than twenty was obtained at the lower pressure of less than 600 Pa and the lower temperature of less than –40 °C.

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Deep lateral anhydrous HF/methanol etching for MEMS release processes

Cited by 9 publications

References 5 publications

High-performance long wave infrared bolometer fabricated by wafer bonding

High-performance long wave infrared bolometer fabricated by wafer bonding

Semiconductor cleaning technology for next generation material systems

Etching selectivity of SiO₂ to SiN using HF and methanol at higher pressures up to 900 Pa

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Deep lateral anhydrous HF/methanol etching for MEMS release processes

Cited by 9 publications

References 5 publications

High-performance long wave infrared bolometer fabricated by wafer bonding

High-performance long wave infrared bolometer fabricated by wafer bonding

Semiconductor cleaning technology for next generation material systems

Etching selectivity of SiO2 to SiN using HF and methanol at higher pressures up to 900 Pa

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Product

Resources

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Etching selectivity of SiO₂ to SiN using HF and methanol at higher pressures up to 900 Pa