6 October 2014

EVG unveils covalent bonder for engineered substrate and power device production

EV Group (EVG) of St Florian, Austria (a supplier of wafer bonding and lithography equipment for MEMS, nanotechnology and semiconductor applications) has launched the EVG580 ComBond high-vacuum wafer bonding system, which enables electrically conductive and oxide-free covalent bonds at room temperature. Built on a modular platform to support high-volume manufacturing (HVM) requirements, the new system is suited to bonding different substrate materials together in order to enable higher-performing devices and new applications, including multi-junction solar cells; silicon photonics; high-vacuum MEMS packaging; power devices; and compound semiconductor and other advanced engineered substrates for ‘beyond CMOS’ applications such as high-mobility transistors, high-performance/low-power logic and radio frequency (RF) devices.

Picture: The EVG580 ComBond automated high-vacuum wafer bonding system.

Several EVG580 ComBond systems have already been shipped to device makers and R&D centers. Customer demonstrations are available at EVG's corporate headquarters.

“During the recent installation and acceptance test phase our new EVG580 ComBond has demonstrated its capacity to create excellent covalent bonds at room temperature,” says Fabrice Geiger, VP Silicon Technologies Division at micro/nanotechnology R&D center CEA-Leti of Grenoble, France. “CEA-Leti is looking forward to working with EVG within our Common Lab on implementing the EVG580 ComBond to further development activities in several key areas,” he adds.

“The EVG580 ComBond system masters the crucial surface preparation steps that are needed to ensure contamination- and oxide-free bonds at room temperature” says EVG’s executive technology director Paul Lindner. “We can bond nearly anything on anything — creating many different material combinations in wafer form,” he adds. “This supports our customers’ efforts to develop and ramp new devices into mass production to enable a variety of emerging and high-growth applications — from the development of silicon photonics for next-generation telecommunications to more advanced power devices that can enable electric vehicles to drive longer distances between charges.”

Challenges with combining compound semiconductors and silicon

Combining materials with different properties to produce electronic devices, such as III-V compound semiconductor materials like gallium nitride (GaN), gallium arsenide (GaAs) and indium phosphide (InP) with silicon substrates, can lead to enhanced device performance due to higher carrier mobility as well as open up new capabilities such as the emission of light through silicon, which can enable optical interconnects and routers, says EVG. However, combining these materials through traditional epitaxial growth processes leads to crystal dislocation defects due to differences in lattice constant and coefficient of thermal expansion (CTE), which in turn degrade performance.

Benefits of wafer bonding

These manufacturing issues can be mitigated by growing each semiconductor material separately on optimized growth substrates and then combining them through wafer bonding, sayas EVG. Room-temperature covalent bonding, in particular, is a suitable choice since it eliminates the need for annealing processes, which generate high temperatures that can add additional stress due to CTE mismatch. However, a key limitation of room-temperature covalent bonding has been the inability to maintain tight control of the thickness and uniformity of the bond interface layer, including effective removal of particle contaminants and the native oxide layers, which is necessary to achieve an interface that has both sufficient bond strength and electrical conductivity between the bonded materials. The EVG580 ComBond addresses these limitations, says the firm.

Key features

Key features of the EVG580 ComBond include the following:

• a dedicated ComBond Activation Module (CAM) seamlessly integrated into the platform, which provides advanced surface preparation by directing energized particles to the substrate surface instead of wet chemical etching to achieve a contamination-free and oxide-free bond interface;
• operation in a high-vacuum process environment, preventing re-oxidation of the treated wafers prior to the bonding step;
• configurable with up to five modules that can process in parallel to support both R&D and HVM applications; and
• processing of wafer sizes up to 8-inches (200mm).

EVG at SEMICON Europa

EVG is exhibiting in booth #918 at SEMICON Europa 2014 in the ALPEXPO, Grenoble, France (7-9 October). Also, the firm’s representatives are presenting ‘Future of MEMS: Market and technologies perspective’ at the International MEMS Industry Forum (9:50-10:10, 7 October), ‘Hybrid wafer bonding for 3D IC’ at the 3D Integration Session (15:40-16:00, 8 October) and ‘Nanoimprint status for HVM’ at the Lithography Session (13:10-13:30, 9 October).

See related items:

Fraunhofer ISE teams with EVG to enable direct wafer bonding for next-gen solar cells

EVG extends wafer bonding equipment and process solutions for covalent bonding technology

Tags: EV Group

Visit: www.evgroup.com/118694/118810/142472/EVG580_ComBond_ShortBrochure.pdf