Transcript No Slide Title

Microassembly – deterministic
• Sequential: pick and place
• Keller
• Yeh
• Wafer scale
• On-wafer (Magnetic, triboelectric, motorized,
residual stress, …)
• Wafer-to-wafer (Howe, Cohn, Bright)
MEMS Design & Fab
ksjp, 7/01
• Micro-packaging
MEMS Design & Fab
ksjp, 7/01
Micro-Tweezers (memspi.com)
Tweezers holding optical fiber
Design: Chris Keller
Fab: Sandia
MEMS Design & Fab
ksjp, 7/01
Courtesy: MEMS Precision Instruments
Tweezer gripping Hexsil gear
MEMS Design & Fab
ksjp, 7/01
Courtesy: MEMS Precision Instruments
Comparison with Commercial subretinal tweezer
(Storz)
MEMS Design & Fab
ksjp, 7/01
Photos courtesy Chris Keller,
MEMS Precision Instruments
www.memspi.com
Synthetic Insects
(Smart Dust with Legs)
Goal: Make silicon walk.
MEMS Design & Fab
ksjp, 7/01
•Autonomous
•Articulated
•Size ~ 1-10 mm
•Speed ~ 1mm/s
Actuating the Legs
1st Link
Motor
1mm
MEMS Design & Fab
ksjp, 7/01
2nd Link
Motor
Magnetic Parallel Assembly
Parallel assembly of Hinged Microstructures Using Magnetic Actuation
Figure 1. (a) An SEM micrograph of a Type I structure. The flap is
allowed to rotate about the Y- axis. (b) Schematic cross-sectional view
of the structure at rest; (c) schematic cross-sectional view of the flap as
Hext is increased.
Solid-State Sensor and Actuator Workshop
Hilton Head 1998
Figure 2. (a) SEM micrograph of a Type II structure. (b) Schematic
cross-sectional view of the structure at rest; (c) schematic crosssectional view of the structure when Hext is increased.
MEMS Design & Fab
ksjp, 7/01
Yong Yi and Chang Liu
Microelectronics Laboratory
University of Illinois at Urbana-Champaign
Urbana, IL 61801
Sequential parallel assembly
Parallel assembly of Hinged Microstructures Using Magnetic Actuation
Yong Yi and Chang Liu
Microelectronics Laboratory
University of Illinois at Urbana-Champaign
Urbana, IL 61801
Figure 8. Schematic of the assembly process for the flap 3-D devices.
(a) Both flaps in the resting position; (b) primary flap raised to 90º at
Hext = H1; (c) full 3-D assembly is achieved at Hext = H2 (H2 > H1 ).
Solid-State Sensor and Actuator Workshop
Hilton Head 1998
MEMS Design & Fab
ksjp, 7/01
Figure 9. An SEM micrograph of a 3-D device using three Type I flaps.
The sequence of actuation is not critical to the assembly of this device.
Assembly via Residual Stress
Low Insertion Loss Packaged and Fiber-Connectorized Si
Surface-Micromachined Reflective Optical Switch
V. Aksyuk, B. Barber, C. R. Giles, R. Ruel, L. Stulz, and D. Bishop
Bell Laboratories, Lucent Technologies, 700 Mountain Ave.
Murray Hill, NJ 07974
is deposited on a polysilicon beam anchored at one end. Upon release the
metal-poly sandwich structure deforms, moving the free end of the beam
upward. The lifting structure engages the cut in the hinged-plate shutter
causing it to rotate 90 degrees into tits operating position.
MEMS Design & Fab
ksjp, 7/01
Figure 2. Self-Assembling optical shutter. High tensile residual stress metal
MEMS Design & Fab
ksjp, 7/01
Parallel Assembly via Triboelectricity
OMM 16x16 switch
From www.omminc.com
256 hinged mirrors!
MEMS Design & Fab
ksjp, 7/01
•
•
Parallel Assembly via Surface Tension
Reflow
Silicon substrate
• Compact, parallel process assembly
• Accuracy and reliability ?
Syms, then Bright
MEMS Design & Fab
ksjp, 7/01
Silicon substrate
MEMS Design & Fab
ksjp, 7/01
Solder-assembly (Rich Syms)
Taxonomy of Microassembly
• Parallel microassembly
• Multiple parts assembled simultaneously
• Deterministic: pre-determined destination
for parts
• Stochastic: random process determines part
destinations
• Serial microassembly
Courtesy: Roger Howe, UCB
MEMS Design & Fab
ksjp, 7/01
• “Pick and place” on a microscale
K. Böhringer, et al, ICRA, Leuven, Belgium, May 1998
Courtesy: Roger Howe, UCB
MEMS Design & Fab
ksjp, 7/01
Parallel Microassembly Processes
Stochastic Parallel Microassembly
• Agitated parts find minimum energy state via an
annealing process
Courtesy: Roger Howe, UCB
MEMS Design & Fab
ksjp, 7/01
• Gravitational well: J. S. Smith, UC Berkeley and
Alien Technology Corp., Morgan Hill, Calif.
• (video)
• Patterned chemical “binding sites”
G. M. Whitesides, Harvard: hydrophobic surfaces
formed by self-assembled monolayers define the
binding site
Biomimetic Approach
•
Pattern part surfaces with
hydrophobic and hydrophilic
regions using self-assembled
monolayers (SAMs).
• free energy cost of SAM-water
interface is high
• hydrophobic regions act as
binding sites
Courtesy: Roger Howe, UCB
MEMS Design & Fab
ksjp, 7/01
Terfort, A. et al. Nature, 386, 162-4 (1997).
Application to Microassembly
•
Pattern complementary hydrophobic
shapes onto parts and substrates
using SAMs.
• no shape constraints on parts
• no bulk micromachining of
substrate
• submicron, orientational alignment
Uthara Srinivasan, Ph.D. thesis,
UC Berkeley Chem.Eng., May 2001
Courtesy: Roger Howe, UCB
MEMS Design & Fab
ksjp, 7/01
•
Mirrors onto Microactuators
Self-assemble mirrors
onto microactuator arrays
• Si (100) mirrors
• Nickel-polySi bimorph
actuators
U. Srinivasan, M. Helmbrecht, C. Rembe, R. T. Howe,
and R. S. Muller, IEEE Opto-MEMS 2000 Workshop,
Kawai, Hawaii, Aug. 21-24, 2000
Courtesy: Roger Howe, UCB
MEMS Design & Fab
ksjp, 7/01
•
Unreleased Mirrors
•
Si mirror
Si(100) mirror
array with binding
sites, fabricated
from SOI wafer
binding site
Courtesy: Roger Howe, UCB
MEMS Design & Fab
ksjp, 7/01
oxide
Courtesy: Roger Howe, UCB
MEMS Design & Fab
ksjp, 7/01
Mirrors in Solution
Moore’s Law, take 2
MEMS Design & Fab
ksjp, 7/01
• Nanochips on a dime (Prof. Steve Smith, EECS)
Mirror on Released Actuator
binding site
Courtesy: Roger Howe, UCB
MEMS Design & Fab
ksjp, 7/01
assembled mirror
Mirrors on Microactuators
Courtesy: Roger Howe, UCB
MEMS Design & Fab
ksjp, 7/01
assembled mirror
Mirror Curvature
• Heat-cured
acrylate
adhesive
Courtesy: Roger Howe, UCB
MEMS Design & Fab
ksjp, 7/01
• Mirror
curvature less
than 30 nm
Research Challenges for Self-Assembly Processes
• Assembly extensions:
• multi-pass and multi-part simultaneous assembly
• Reduce area consumed by binding site, in order to
achieve:
Courtesy: Roger Howe, UCB
MEMS Design & Fab
ksjp, 7/01
• “High quality” mechanical interconnects
• “High density” electrical interconnects
Post-Assembly Processes
• Polymer adhesives are not sufficient for many
•
MEMS applications
Good interfaces require high temperatures (>
450o C), which can damage microcomponents
Courtesy: Roger Howe, UCB
MEMS Design & Fab
ksjp, 7/01
• Potential solutions:
Local heating through laser
Local resistive heating (Prof. Liwei Lin, UC
Berkeley)
Flat, thin gold mirror with a thick
Copper frame transferred from source
Substrate to MUMPS die.
Maharbiz, Howe, Pister, Transducers 99
MUMPS part by M. Helmbrecht
MEMS Design & Fab
ksjp, 7/01
Chip-to-chip and wafer-wafer assembly
ksjp, 7/01
MEMS Design & Fab
ksjp, 7/01
MEMS Design & Fab
ksjp, 7/01
MEMS Design & Fab
MEMS Design & Fab
ksjp, 7/01
Remove
substrate!
MEMS Design & Fab
ksjp, 7/01
Could be 2-axis
ksjp, 7/01
MEMS Design & Fab
•
•
IC Packaging extremely well developed
•
•
•
•
Reliability
Thermal conductivity
Cost
Size
Not well addressed
• Packaging with unfilled volumes
• Packaging in non-standard ambients
• Vacuum
• Dry N2
• Moist N2
• 100 mTorr +/- 1%
• Fiber feedthroughs
Somewhat addressed
• Optical I/O
• Packaging induced stresses
MEMS Design & Fab
ksjp, 7/01
•
Packaging
2x2 MEMS Fiber Optic Switches
2x2 MEMS Fiber Optic Switches with Silicon Sub-Mount for Low-Cost Packaging
Shi-Sheng Lee, Long-Sun Huang, Chang-Jin “CJ” Kim and Ming C. Wu
Electrical Engineering Department, UCLA
63-128, engineering IV Building, Los Angeles, California 90095-1594
Mechanical and Aerospace Engineering Department
Figure 1. SEM of the 2x2 MEMS fiber optic switch.
MEMS Design & Fab
ksjp, 7/01
Figure 3. SEM of the torsion mirror device.
Introduction to MEMS
2x2 MEMS Fiber Optic Switches
2x2 MEMS Fiber Optic Switches with Silicon Sub-Mount for Low-Cost Packaging
Shi-Sheng Lee, Long-Sun Huang, Chang-Jin “CJ” Kim and Ming C. Wu
Electrical Engineering Department, UCLA
63-128, engineering IV Building, Los Angeles, California 90095-1594
Mechanical and Aerospace Engineering Department
Figure 10. SEM of the fiber and ball lens assembly.
Solid-State Sensor and Actuator Workshop
Hilton Head 1998
MEMS Design & Fab
ksjp, 7/01
Figure 4. SEM of the vertical torsion mirror.
ksjp, 7/01
MEMS Design & Fab
ksjp, 7/01
MEMS Design & Fab
Assembly - Summary
• Pick-and-place assembly is the standard of
the IC industry!
• Chips, passives into lead frames
• Bond wires
• Cost is ~1 penny/operation
• Parallel assembly is coming
MEMS Design & Fab
ksjp, 7/01
• Wafer-wafer transfer (deterministic)
• Fluidic self-assembly (stochastic)