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- Bleiker, Simon J., et al.
(författare)
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Cost-Efficient Wafer-Level Capping for MEMS and Imaging Sensors by Adhesive Wafer Bonding
- 2016
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Ingår i: Micromachines. - Basel, Switzerland : Multidisciplinary Digital Publishing Institute (MDPI). - 2072-666X. ; 7:10, s. 192-
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Tidskriftsartikel (refereegranskat)abstract
- Device encapsulation and packaging often constitutes a substantial part of the fabrication cost of micro electro-mechanical systems (MEMS) transducers and imaging sensor devices. In this paper, we propose a simple and cost-effective wafer-level capping method that utilizes a limited number of highly standardized process steps as well as low-cost materials. The proposed capping process is based on low-temperature adhesive wafer bonding, which ensures full complementary metal-oxide-semiconductor (CMOS) compatibility. All necessary fabrication steps for the wafer bonding, such as cavity formation and deposition of the adhesive, are performed on the capping substrate. The polymer adhesive is deposited by spray-coating on the capping wafer containing the cavities. Thus, no lithographic patterning of the polymer adhesive is needed, and material waste is minimized. Furthermore, this process does not require any additional fabrication steps on the device wafer, which lowers the process complexity and fabrication costs. We demonstrate the proposed capping method by packaging two different MEMS devices. The two MEMS devices include a vibration sensor and an acceleration switch, which employ two different electrical interconnection schemes. The experimental results show wafer-level capping with excellent bond quality due to the re-flow behavior of the polymer adhesive. No impediment to the functionality of the MEMS devices was observed, which indicates that the encapsulation does not introduce significant tensile nor compressive stresses. Thus, we present a highly versatile, robust, and cost-efficient capping method for components such as MEMS and imaging sensors.
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| 2. |
- Schenk, Linda, 1980-, et al.
(författare)
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Industry Derived Occupational Exposure Limits : A Survey of Professionals on the Dutch System of Exposure Guidelines
- 2019
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Ingår i: Annals of Work Exposures and Health. - : Oxford University Press. - 2398-7308 .- 2398-7316. ; 63:9, s. 1004-1012
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Tidskriftsartikel (refereegranskat)abstract
- The Netherlands' system for occupational exposure limits (OELs) encompasses two kinds of OELs: public and private. Public OELs are set by the government. Private OELs are derived by industry and cover all substances without a public OEL. In parallel, the regulation concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) has introduced an exposure guidance value similar to the OEL, namely the Derived No-Effect Level (DNEL) for workers' inhalation exposure. This study aimed to investigate issues encountered by occupational health professionals regarding private OELs, and how they perceive the DNELs for workers in relation to private OELs. Towards this aim, we sent out a web-based questionnaire to the members of the Dutch professional organization for occupational hygienists (Nederlandse Vereniging voor Arbeidshygiene [NVVA], n = 513) and to members of the Dutch professional organization for safety engineers (NVVK, n = 2916). Response rates were 27% (n = 139) and 7% (n = 198), respectively. More occupational hygienists (59%) than safety engineers (17%) reported to derive private OELs themselves. Our respondents reported several challenges with the derivation of private OELs. Fifty-one percent of the occupational hygienists and 20% of the safety engineers stated to see a role of REACH Registrants' worker DNELs as private OELs. However, more than half of our respondents were undecided or unfamiliar with worker DNELs. In addition, stated opinions on where worker DNELs fit in the hierarchy of private OELs varied considerably. To conclude, both these professional groups derive private OELs and stated that they need more guidance for this. Furthermore, there is a lack of clarity whether worker DNELs may qualify as private OELs, and where they would fit in the hierarchy of private OELs.
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