Microsystem Integration and Packaging
Microstructure Fabrication and Packaging
RTI International is a leader in the research and development of innovative materials,
microstructures, and devices for microsystem integration and packaging. RTI’s
extensive experience in back-end-of-line processing makes us an ideal partner for the
development or implementation of 3D microstructures on passive and active IC wafers
in the areas of wafer-level vacuum packaging, monolithic device integration, and
vacuum microelectronics. Fully integrated fabrication and analytical facilities, staffed
with full-time engineers and researchers, allow RTI to support a diverse project base
developing new technologies and solutions for our clients.
RTI works with a wide variety of clients and partners,
bringing integrated process, design, testing, and analysis
capabilities to projects involving custom, applicationdriven development. We offer access to standard and nonstandard microfabrication processes for microstructure
fabrication and packaging. The available processes include
standard thin film deposition, photolithography, and
etching (wet and dry), as well as non-standard processes
such as silicon (Si) deep reactive ion etching, patterned
electroplating, ion milling, conformal metal and dielectric
coatings, and thermocompression and solid/liquid
diffusion bonding.
Wafer-Level Vacuum Packaging
Micro-machined Si posts
Metal-metal bonded hermetic seal
Pattern electroplated Cu/Sn
interconnects for high density
interconnect bonding
RTI has been developing and implementing metalmetal bonding for wafer-level vacuum packaging of
microelectromechanical system (MEMS) devices. Metal
seal rings are fabricated on device wafers and their
corresponding window/cap wafers using processes
compatible with standard ICs. As needed, getter material
can be added to the window/cap wafers to provide
additional capability for higher vacuum levels in the sealed
devices. Seal rings are bonded through diffusion processes
to form hermetically sealed devices. The resulting metal
seals are thermally and mechanically stable for downstream
dicing and assembly processing.
www.rti.org
Microstructure Fabrication and Packaging
Monolithic Device Integration
RTI can fabricate device structures directly on IC or passive
substrate wafers. We can work collaboratively with you and
your customers to transfer technologies or develop designs
and processes for monolithic integration of structures.
Since 2002, RTI has been successfully fabricating pixilated,
suspended bridge structures on IC wafers for infrared scene
projector applications. The fabrication sequence for these
MEMS-like structures was part of a technology transfer to RTI
and includes non-standard semiconductor device materials
and processes. RTI successfully delivered fully functional
arrays from the initial validation lot that met the customer’s
performance specifications. Over the years, continued process
modifications and materials development work with the
customer have led to improved pixel performance and yield,
while enhancing our process and design knowledge for other
monolithic device integration applications.
as non-standard processes such as high-rate diamond etching.
Microtriodes providing the backbone for an integrated
vacuum circuit platform have also been demonstrated. These
structures use carbon nanotube field emitters selectively
grown onto hinged polysilicon panels that are then assembled
into active devices. This technology has been implemented as
electron and ion sources for miniature mass spectrometers.
Tilt-view SEM image of gold helix
fabricated on a diamond substrate
for a 650 GHz backward wave
oscillator
Tilt-view SEM image of an RTI
fabricated vacuum triode with
beam focusing capabilities
Working with RTI
Tilt-view SEM image of suspended bridge structures fabricated at RTI
on an IC wafer
3D Microstructures for Vacuum Microelectronics
Using a combination of standard and non-standard
microfabrication techniques, RTI has successfully
developed and produced 3D microstructures for vacuum
microelectronic applications such as THz devices and electron
sources. Vacuum electronics technology is advantageous for
high-power, high-frequency applications and for circuits
operating in harsh environments. The microstructures for
THz sources and amplifiers were developed as part of a
program to build high-power THz frequency communications
and imaging systems for government use. These structures use
RTI’s expertise in isotropic and anisotropic silicon etching,
electroplating, and high-density interconnect bonding as well
RTI is a not-for-profit company and ITAR registered
organization that offers a “safe harbor” development
environment to its clients. We work with a diverse base of
commercial clients, government agencies, and academic
institutions, supporting our clients through application-driven
technology development programs, custom prototyping,
and small-volume production. We also partner with external
organizations for joint proposals in a variety of government
and defense programs, including SBIR and STTR programs.
More Information
John Lannon
Center for Materials and
Electronic Technologies
919.248.1872
lannon@rti.org
www.rti.org/microsystem
RTI International
3040 E. Cornwallis Road, PO Box 12194
Research Triangle Park, NC
27709-2194 USA
RTI8342 0313
RTI International is one of the world’s leading research institutes, dedicated to improving the human condition
by turning knowledge into practice. Our staff of more than 3,700 provides research and technical services to
governments and businesses in more than 75 countries in the areas of health and pharmaceuticals, education and
training, surveys and statistics, advanced technology, international development, economic and social policy, energy
and the environment, and laboratory testing and chemical analysis. For more information, visit www.rti.org.
RTI International is a trade name of Research Triangle Institute.