Sodium contamination in integrated MEMS packaged by anodic bonding

Henriksen, Kristin; Jensen, Geir Uri; Hanneborg, A.; Jakobsen, Henrik

doi:10.1109/memsys.2003.1189827

Cited by 4 publications

(2 citation statements)

References 11 publications

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“…For these reasons, characterization of sodium contamination during anodic bonding is essential. We have presented initial results, using MOS capacitors as test structures, showing that sodium contamination of SiO 2 does occur during anodic bonding [19]. In this paper, we continue our investigation, including the effects of varying bonding parameters on the contamination.…”

Section: Introductionmentioning

confidence: 87%

Sodium contamination of SiO₂caused by anodic bonding

Schjølberg-Henriksen

Jensen

Hanneborg

et al. 2003

J. Micromech. Microeng.

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In this paper we present an investigation of sodium contamination of SiO2 (oxide) during anodic bonding. Sodium contamination can be deleterious to the electrical properties of silicon structures. Silicon wafers with metal–oxide semiconductor (MOS) capacitors were bonded to Corning 7740 (Pyrex) glass wafers. The concentration of mobile ions was measured on capacitors outside and within glass cavities using the triangular voltage sweep method. Using secondary ion mass spectrometry analysis, it was confirmed that the ions were sodium. We found an increase in sodium concentration Nm between 1010 and 1013 cm−2, depending on the oxide location and the geometry of the glass cavity. The gate aluminium of the MOS capacitor was found to partly shield the oxide from contamination, causing a two to five times smaller increase in Nm. Reducing the bonding voltage from 800 to 500 V did not affect the increase in Nm significantly. In contrast, changing the ambient in the bonding chamber from vacuum to 1020 mbar air, reduced the contamination of capacitors situated outside the glass. A plasma-enhanced chemical vapour deposited Si3N4 film was found to be very beneficial in protecting the capacitors. The Si3N4 prevented sodium contamination of the capacitors situated within the glass cavities, and radically reduced the contamination of the capacitors situated outside the glass. The results suggest that the contaminating sodium originated from the bulk glass.

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Section: Introductionmentioning

confidence: 87%

Sodium contamination of SiO₂caused by anodic bonding

Schjølberg-Henriksen

Jensen

Hanneborg

et al. 2003

J. Micromech. Microeng.

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“…Defects induced by particulates are classified into three categories: surface, anchor, and broken structures [78]. Other forms of contamination include ionic contamination [79] and lead contamination [80].…”

Section: Environmentally Induced Failurementioning

confidence: 99%

An Overview of Reliability and Failure Mode Analysis of Microelectromechanical Systems (MEMS)

Jiang

Handbook of Performability Engineering

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Abstract:The reliability issues concerning on microelectromechanical systems (MEMS) have steadily developed in recent years. One of the processes to understand MEMS reliability is to know the failure modes of these microdevices. In this chapter, we seek to report on both well known and unknown failure modes of MEMS. Most of the failure patterns are the same in nanoelectromechanical systems (NEMS), because NEMS followed a developmental path similar to that of MEMS in functional design, materials, and fabrication. Therefore, the existing results of MEMS failure modes can be used as a reference to nanoscale system reliability research. The failure modes discussed in this chapter contain stiction, wear, fracture, crystallographic defect, creep, degradation of dielectrics, environmentally induced failure, electric related failure, parasitic capacitance, dampening effects, delamination, and packaging.

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