Here is the abstract you requested from the DPC_2007_Mems technical program page. This is the original abstract submitted by the author. Any changes to the technical content of the final manuscript published by IMAPS or the presentation that is given during the event is done by the author, not IMAPS.
|Wafer Bonding for MEMS: Low Temperature Processes using Plasma Activation|
|Keywords: low temperature, wafer bonding, MEMS packaging|
|As Micro-Electro-Mechanical Systems (MEMS) devices are by definition tri-dimensional architectures, wafer bonding became in last decade an important technology with applications in assembling and packaging of such devices. Wafer bonding is a technique used to join two materials by bringing in contact their surfaces. The two surfaces have to be very flat, smooth and clean in order to allow adhesion to occur. Being a wafer scale process, wafer bonding brings some major advantages like improved throughput, increased yield, allows devices testing at wafer scale (prior to dicing). Wafer bonding is of high interest in MEMS devices packaging by enabling costs decrease through Wafer Level Packaging (currently MEMS packaging may represent up to 80% of the total device costs). As the high temperature thermal annealing required for reaching the maximum bond strength limits in some cases wafer bonding, development of low temperature processes (maximum temperature: 400°C) became crucial for expanding the field of applications of wafer bonding. Plasma activated wafer bonding consists in surface activation of substrates prior to bonding by exposing their surfaces to a plasma. The surface activation allows a controlled change in surface chemistry in order to obtain the highest bond strength for low temperature annealing and short annealing times. Plasma activated bonding was successfully applied for direct bonding of different types of materials: silicon, oxides and polymers (PMMA, ZEONEX). The present paper will introduce the principle of this process and will show examples on how plasma activated wafer bonding can be an alternative to standard wafer bonding processes used in MEMS assembling and packaging.|
|V. Dragoi, Chief Scientist
St. Florian, Upper Austria 4782,