Various techniques have been developed to encapsulate isolatable MEMS devices. http://www.selleckchem.com/products/Vandetanib.html Partridge et al. have pioneered the use of epitaxially deposited polysilicon as an encapsulation structure for piezoresistive accelerometers [3]. In extension to the aforementioned work, Rusu et al. studied plasma-enhanced ref 3 chemical vapor deposition polysilicon germanium as an alternate material for device encapsulation Inhibitors,Modulators,Libraries [4]. Meanwhile, Lebouitz et al. used permeable polysilicon to fabricate a vacuum shell over movable elements of a MEMS resonator [5]. Alternate methods involve using chemical vapor deposition sealed micromachined cavity and SiN microshell to protect microstructures [6-7].
Inhibitors,Modulators,Libraries However, all the aforementioned techniques Inhibitors,Modulators,Libraries involve high process temperatures that are detrimental to prefabricated CMOS circuitry, which is often damaged at temperature higher than 450��C.
As a solution, a low temperature process was introduced using electroless nickel cavity as the encapsulation structure [8]. The fabrication process, however, requires an electroplating step, which is less compatible with CMOS and other Inhibitors,Modulators,Libraries pre-fabricated microstructures. In light of these problems, this work attempts to solve the wafer level packaging issues faced by isolatable devices through a simple and economical CMOS compatible microfabrication processes. A novel wafer level encapsulation is introduced, which uses sputtered silicon as main structural layer, eutectic gold-silicon alloy as seal layer, and high strength liquid crystal polymer (LCP) thermoplastic as outer encapsulant layer.
Inhibitors,Modulators,Libraries A Inhibitors,Modulators,Libraries robust encapsulation which could withstand subsequent high pressure plastic packaging is produced only by using and carefully sequencing several CMOS compatible materials and low temperature processes, without the need for expensive packaging procedures and Inhibitors,Modulators,Libraries equipments.2.?MethodologyIn order to assess the feasibility of the proposed packaging technique, sputtered silicon encapsulation was built on an unpackaged MEMSTech 50g non-crossing differential capacitive accelerometer Inhibitors,Modulators,Libraries (Sensfab Pte. Ltd., Singapore). This device is selected due to its size suitability. The device has an adequately large movable elements area for the encapsulation to be built upon.
For this reason, viability of the technique on this Brefeldin_A device would imply its feasibility on other MEMS devices with smaller movable elements area, since all the CMOS compatible processes used could be scaled down.
Moreover, the device structure is planar, yet fairly complicated, which made it practical to gauge kinase inhibitor 17-DMAG the potential of this packaging technique.The accelerometer Cilengitide device has four identical quadrants of accelerometer fingers, with 84 pairs of beams per side, as shown in Figures 1(a) selleck chem inhibitor and 1(b). The device has a set of stationary fingers at each quadrant and a proof mass holding all the movable fingers [Figure 1(b)]. It has sensor die area of 2,350 �� 3,020 ��m2, which includes bond pad area of 652.3 ��m �� 2,331.