Adaptable and integrated packaging platform for MEMS-based combo sensors utilizing innovative wafer-level packaging technologies

Abstract

Wafer-Level Packaging (WLP) has emerged in modern years and played a prominent role in both semiconductor and Integrated Circuit (IC) field, as well as in Micro-ElectroMechanical Systems (MEMS) applications and fields for their distinguishing operating mechanism and adaptive design variety. In this study, numerous kinds of mature packaging technologies combined with innovation as well as integration of WLP techniques were proposed, including low temperature Wafer to Wafer (W2W) bonding using glass frit, wafer sawing and wafer grinding using novel means, wafer-level wire bonding, wafer-level compound molding, compound grinding, post-grinding etching to alleviate wire extrusion, as well as low temperature passivation processes and metal trace patterning which were implemented in Re-Distribution Layer (RDL) stage. Some of these technologies were specified in the later half paragraphs. Major process flow for our WLP platform for MEMS devices like accelerometers, gyroscope, pressure sensors, and even combo sensors were mentioned as well. In addition to technology elaboration and process depiction, relevant experimental results and final Reliability Analysis (RA) test results on package level have also been demonstrated and discussed. Several obstacles during the development stage, including poor adhesion between molding compound and passivation layer, gold wire surface and metal trace layer, overall warpage increase after thermal process in RDL stage, have been investigated. These challenges as well as our proposed solutions have all been addressed in this paper to exhibit SPIL MEMS WLP platform feasibility.

MEMS capacitive accelerometer: A review

“…The most commonly used accelerometers are piezoelectric, piezoresistive, optical, and capacitive accelerometers [5,22]. Piezoelectric accelerometers, which are frequently used in the civil and aerospace industries and generally measure mechanical changes such as vibration and shock, use the piezoelectric effect of certain materials to detect the change in acceleration [23].…”

“…MEMS accelerometers detect the change in capacitance in sudden movement changes and create a signal ensuring the airbag works. Figure 1 shows the common usage areas of MEMS systems [5]. MEMS technology, which consists of a combination of mechanical and electronic systems uses many of the techniques used in the integrated circuit field such as oxidation, diffusion, ion implantation, LPCVD, and sputtering [6,7].…”

Energy Dissipation Contribution Modeling of Vibratory Behavior for Silicon Micromachined Gyroscope

“…In summary, influencing factors on damping losses can contribute to three aspects: vacuum packaging technology, materials properties, and mechanical structure topology. First, vacuum packaging scheme as the 2 Shock and Vibration most common one is used to greatly decrease air damping, such as epi-seal encapsulation process [20][21][22][23][24][25], hermetic lid sealing process [13,[26][27][28], Through-Silicon Via (TSV) process [29,30], and SPIL MEMS WLP process [31]. Second, some different kinds of materials are tried to yield lower the thermoelastic, surface deflect, and Akhiezer damping.…”