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Sankt Florian am Inn, Austria

Uhrmann T.,EV Group | Delmdahl R.,Coherent GmbH
Solid State Technology | Year: 2013

Temporary bonding of wafers to a thick carrier has emerged as a viable method for back thinning and subsequent backside processing. The processed thin wafers are then debonded from this carrier just prior to stacking. The most important advantage of laser debonding over other techniques is that it enables the use of polyimide -based temporary adhesives that can withstand exposure to temperatures as high as 400°C. There are several techniques of bonding wafers such as unpatterned wafer, frontside patterning, frontside bonding to carrier, wafer flipped, backthinning, backside patterning, laser debonding and carrier separation. The temporary adhesive for laser debonding is most commonly spin coated on to the wafer, which is then mated with the carrier. Bonding then occurs under pressure and elevated temperature. Two basic approaches for implementing excimer laser based debonding are line scanning and step-and-repeat. The minimum required laser power for debonding is also very dependent upon wavelength because of absorption in the glass carrier.

Dragoi V.,EV Group
ECS Transactions | Year: 2014

Various Micro- Electro- Mechanical Systems (MEMS) devices are incorporated into mobile electronic devices. A particular category of MEMS devices require vacuum packaging by wafer bonding with the requirement to encapsulate vacuum levels of 10-3 mbar orhigher with long time stability. The vacuum requirement is limiting the choice of the wafer bonding process and raises significant challenges to the existing investigation methods (metrology) used for results qualification. This paper reviews some important aspects related to process choice and provides an overview of the needs to be addresses in terms of metrology for wafer bonding. © The Electrochemical Society.

Dussault D.,ProSys Inc. | Fournel F.,CEA Grenoble | Dragoi V.,EV Group
ECS Transactions | Year: 2012

The increased complexity of microelectronic and sensor applications that have emerged over the past decade have driven wafer bonding to mature as a production technology for both MEMS and 3D stacked die manufacturing. The use of CMOS device wafers has restricted the types of viable bonding processes to low temperature fusion bonding, adhesive bonding and metal bonding. Due to the specific requirements of CMOS technology the allowed bonding processes had to be adapted in order to fulfill the specific CMOS-compatibility demands. This paper presents a novel single wafer Megasonic based cleaning method with enhanced process control capabilities. This cleaning process is integrated in low temperature fusion bonding process and enables higher bonding yields and a reduction in process fluid usage. © The Electrochemical Society.

Dragoi V.,EV Group | Pabo E.,EV Group Inc.
ECS Transactions | Year: 2010

Wafer bonding processes offer valuable solutions not only for MEMS devices but more recently for wafer-level 3D interconnects, advanced packaging and LED applications. The increased complexity of the wafer bonding based applications requires very accurate process design. Unfortunately bonding process selection and design is not always well documented or understood and some important details may not be considered, possibly resulting in major issues during product prototyping or even manufacturing. The main topics to be considered for wafer bonding process selection are summarized and explained. ©The Electrochemical Society.

Dragoi V.,EV Group | Cakmak E.,EV Group Inc. | Pabo E.,EV Group Inc.
Romanian Journal of Information Science and Technology | Year: 2010

Metal -lms can be used as bonding layers at wafer-level in MEMS manufacturing processes for device assembly as well as just for elec- trical integration of di®erent components. One has to distinguish between two categories of processes: metal thermo-compression bonding on one side, and bonding with formation of an eutectic alloy layer or an intermetallic compound. The di®erent process principles determine also the applications area for each. From electrical interconnections to wafer-level packaging (with special emphasis on vacuum packaging) metal wafer bonding is a very important technology in MEMS manufacturing processes.

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