NEG thin films for under controlled atmosphere MEMS packaging

Tenchine, Lionel; Baillin, Xavier; Faure, Christel; Nicolas, P.; Martínez, E.

doi:10.1016/j.proeng.2010.09.122

Cited by 12 publications

(19 citation statements)

References 4 publications

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“…High roughness and porosity induce an increase of both surface gas capacity and sticking probability. The former is simply due to the larger surface area, while the latter is caused by multiple collisions of the impinging molecules inside the surface pores [4,7,12]. Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Discrete packages are very critical to assure an excellent hermeticity in many MEMS devices to perform their basic functions properly and to enhance their reliability by keeping these devices away from the harmful external environment [1][2][3][4]. With the technology trend of increased miniaturization of MEMS devices, maintaining the needed vacuum level in such packages for the entire MEMS device life becomes a real technical challenge due to the very high surface to volume ratio [1].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

ZrCoCe Getter Film Solution for Under Controlled Atmosphere MEMS Packaging

Xu¹,

Cui²,

Cui³

et al. 2015

Proceedings of the International Conference on Advances in Energy, Environment and Chemical Engineering

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Abstract. In order to specifically support the technology trend of increased miniaturization of Micro Electro Mechanical Systems (MEMS) devices, highly porous ZrCoCe non-evaporable getter (NEG) film has been produced by DC magnetron sputtering from a preformed ZrCoCe alloy target. The porous film is composed of columnar crystals, which is further built up with assembled ZrCoCe amorphous or nanocrystalline grains. Gas sorption investigation shows that this film can be activated at low temperature and exhibits excellent stable sorption characteristics. Sorption properties can be further improved with elevating the activation temperatures due to the microstructure modification. The capability of ZrCoCe films withstanding wafer physical or chemical cleaning processes is investigated, indicating their compatibility with MEMS vacuum packaging and the appropriate way to store them. IntroductionDiscrete packages are very critical to assure an excellent hermeticity in many MEMS devices to perform their basic functions properly and to enhance their reliability by keeping these devices away from the harmful external environment [1][2][3][4]. With the technology trend of increased miniaturization of MEMS devices, maintaining the needed vacuum level in such packages for the entire MEMS device life becomes a real technical challenge due to the very high surface to volume ratio [1]. The most common and technically accepted way to maintain a controlled ambient environment in a hermetically sealed MEMS device is to use a NEG capable of chemically absorbing active gasses, such as H 2 O, CO, CO 2 , O 2 , N 2 and H 2 . However, the conventional bulk or sheet getters having the property of high pumping speed even at room temperature, could not be used in these minimizing MEMS devices due to the restricted space [5][6][7]. It is urgently required to develop the highly porous thin-film-type getters with several μm thickness for the applications of MEMS vacuum devices.Ti, Ti-Zr-V, Zr-V-Fe or ZrV 2 are typical NEG film materials, which have been widely studied in sealed-off vacuum technology. Nevertheless, the aforementioned materials may be defined as NEG materials of specific use, and are often described and referred to in patents and technical or commercial bulletins with reference to their use in specific applications [8][9][10]. Zr-Co-rare earth (RE) alloys are specially developed to fulfil some specific integration needs. These alloys are advantageous because they are suitable for general use. they have a relatively low activation temperature 200-500°C, are capable of sorbing a wide variety of gases, and minimize the environmental and safety risks compared with known nonevaporable getter alloys [11].It is known from previous studies that ZrCoRE films have been prepared by RF magnetron sputtering and sorption properties can be improved by optimizing related parameters [12,13]. However, the performance of the above films are too low to fulfil practical applications and mass production. More efficient sorption capacity and higher sta...

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

ZrCoCe Getter Film Solution for Under Controlled Atmosphere MEMS Packaging

Xu¹,

Cui²,

Cui³

et al. 2015

Proceedings of the International Conference on Advances in Energy, Environment and Chemical Engineering

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“…The experimental procedure has already been presented in previous studies [7][8]. It is based on the sealing of samples in a glass ampoule.…”

Section: Outgassing Characterization Methodsmentioning

confidence: 99%

“…A selection among the used materials or thermal treatment before sealing can therefore be considered to reduce their influence on pressure increase inside the cavity. In a second part the possibility of reducing the pressure after sealing is explored through the use of a getter material previously studied by Tenchine [7]. The compatibility between the nature of the released gases and the ability of the getter to chemisorb them is evaluated following the same procedure.…”

Section: Figure 1 Thin Film Packaging Fabrication Processmentioning

confidence: 99%

Outgassing characterization of MEMS thin film packaging materials

Savornin

Baillin

Blanquet

et al. 2013

2013 IEEE 63rd Electronic Components and Technology Conference

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In the field of MEMS packaging technology the pressure limit inside the cavity is a crucial parameter. As the cavity size becomes smaller and smaller the vacuum is mainly affected by the outgassing of the materials used in the fabrication process. A full characterization of this phenomenon for oxides that can be integrated as encapsulation layer is presented in this study. A combination of dynamic outgassing, Residual Gas Analysis (RGA) and thermodynamic simulations is involved to fully investigate the material outgassing behavior. The temperature and the nature of released gases are evaluated indicating the optimal annealing or other cleaning process before the sealing of cavities. Moreover the combination of these oxides with a getter material is analyzed. The affinity between carbon dioxide, nitrogen, hydrogen and the getter material is demonstrated as well as its non-reactivity with hydrocarbons. The pressure inside the cavity can be efficiently decreased by integrating this pumping material. Therefore a selection of materials and new fabrication processes can be considered using those results.

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“…5 Consequently, integrating getter films into the MEMS cavities to obtain and maintain the vacuum has been increasingly studied in the recent years. 6,7 Although some wafer-level packaging processes could allow multiple activation of the getter film, the getter film is usually thermally activated only once after cavity sealing with a background pressure typically in the 10 À3 -10 À1 mbar range. In this respect, it is quite different from the case of thermal activation of getter films used in ultrahigh vacuum chambers.…”

Section: Introductionmentioning

confidence: 99%

Oblique angle deposition of Au/Ti porous getter films

Moulin

Bosseboeuf

2018

Journal of Applied Physics

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Interdiffusion in gold/titanium films with titanium evaporated on silicon at different oblique angles (0 , 30 , 50 , and 70) and gold evaporated under normal incidence is investigated using a scanning electron microscope and in-situ sheet resistance measurements for the optimization of the films' effective gettering ability during and after a low-temperature thermal activation. Films have a tilted columnar structure and a porosity increasing with the deposition angle in agreement with calculated values. The oxygen effective gettering ability, characterized by energy-dispersive X-ray spectroscopy, increases with the deposition angle. It is shown that the gold/titanium film with titanium deposited with an oblique angle of 50 is an optimized condition to obtain the largest sorption capacity after 1 h thermal activation at temperatures lower or equal to 300 C. This film has a low initial residual stress that becomes highly tensile if thermal activation is performed above 300 C.

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NEG thin films for under controlled atmosphere MEMS packaging

Cited by 12 publications

References 4 publications

ZrCoCe Getter Film Solution for Under Controlled Atmosphere MEMS Packaging

ZrCoCe Getter Film Solution for Under Controlled Atmosphere MEMS Packaging

Outgassing characterization of MEMS thin film packaging materials

Oblique angle deposition of Au/Ti porous getter films

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