Package, Process & Microassembly

Research that includes:

  • Low temperature MEMS-on-CMOS Silicon-Germanium process for adding MEMS to finished CMOS wafers or dice
  • Silicon Carbide process for adverse environment MEMS and high frequency RF resonators
  • Localized bonding: eutectic, fusion, solder, laser, inductive, rapid thermal processing, and ultrasonic; suitable for device level or wafer level packaging or sealing applications to plastic, glass, silicon and Bio materials, including liquid encapsulation
  • Fluidic microassembly for post-process combining of dissimilarly processed microdevices
  • Carbon nanotube and silicon nanowire directional growth in post-process, low ambient temperature environments
  • Stiction mitigation for MEMS

BPN306: SiC TAPS: Ion Beam Assisted Deposition (IBAD) Encapsulation

Debbie G. Jones

The goal of this project is to develop a low temperature, wafer-level vacuum encapsulation technique for harsh environment, silicon carbide (SiC) sensors.

Project end date: 08/07/07

BPN389: SiC TAPS: Characterization of Silicon Carbide Ion Beam Assisted Deposition (IBAD) Films

Matt Chan

Silicon Carbide (SiC) is an appealing material for harsh environment MEMS applications. It can be sputtered at low temperatures by an Ion-Beam Assisted Deposition (IBAD) system to produce amorphous thin-films and vacuum encapsulations. The goal of this project is to investigate the stress-temperature relation of these amorphous SiC films in order to calculate their biaxial moduli and coefficients of thermal expansion. The “double-substrate technique” is employed to compare the differences in these properties for films that are sputtered both with and without ion-beam assistance...

BSAC5: VUV Lamp Assembly for Wafer Scale Surface Modification

Matthew Wasilik

Liftoff is a processing technique often preferred for patterning metal thin films. In a liftoff process, the resist is patterned first, and then the metal film is deposited. After metal deposition, the resist is dissolved and – if the process has been optimized to insure poor metal step coverage - the unwanted metal is removed (“lifted off”) from the regions where the remaining resist is dissolved. Liftoff is preferable for difficult to etch metals, in cases where the metal etch has a poor selectivity relative to underlying layers and in situations that require minimizing...

BPN387: Modeling of Temperature Effects on Piezoresistor Sensitivity

Zachary Lee

Joule heating occurs in any conductor when current passes through it due to the resistance of the conductor. Semiconductor strain gauges in particular are very susceptible to such temperature changes as they can cause significant fluctuations in the resistance of the gauge itself. This is generally referred to as self-heating of the strain gauge. Self-heating effects are undesirable as they can drastically decrease the signal-to-noise ratio of the strain gauges. In order to improve the sensitivity of a strain gauge it is of interest to characterize the thermal effects of the current...

APP80: Micro Plastic Injection Molding: Microneedle Molding

Julian Lippmann

This project along with APP79 investigates the manufacturing and integration of um scale plastic parts through injection molding. Emphasis is placed on developing robust, but simple fabrication methods capable of molding microneedles 100um X 100um hollow tubes. The issues to be addressed span the micro and meso regimes. At the microscale effort focuses on creating accurate, robust molds that can deliver MEMS scale needles. On the mesoscale, Plastic injection materials and processes are being investigated to yield optimum results.

Project end date: 01/23/08

RM7/RTH: Dedicated SiC MEMS LPCVD Reactor for Access through the DARPA MEMS Exchange Program

Christopher S. Roper

This project seeks to make Silicon Carbide thin films available to MEMS researchers and designers. A process developed in the Maboudian Lab at UC Berkeley which currently accommodates 2-inch wafers will be scaled up to accommodate 4- and 6-inch wafers. High quality poly-crystalline 3C-SiC films deposited at reasonable growth rates, with controlled residual stress, controlled strain gradient, controlled resistivity, and high uniformity will be sought. Once films with high overall quality and repeatability are grown the process will be released to the MEMS community.


APP79: MEMS Biopolymer: Micro Plastic Injection Molded Fluidic Chip with Thermally Actuated Hydrogel Valves

Emil J. Geiger

The goal of this project is to develop a polymer microfluidic system to test system level performance. The chip will be plastic injection molded with integrated fluidic interconnects. Polymer film with patterned metal traces will be used to enclose the channel. The traces will allow simple control elements such as heaters and electrodes to be integrated into the chip. Previous work at UC Berkeley has developed a thermal sensitive hydrogel valve that can be lithographically patterned. This valve will be incorporated into the chip and actuated via on-chip heaters. A test assay will be...

BPN307: CMOS Integrated Nanowires/Nanotubes (CMOS-Inn)

Yingqi Jiang

The goal of this project is to develop technologies for hierarchical assembly of nano structures (silicon nanowires (SNWs) and carbon nanotubes (CNTs)) with built-in CMOS interface circuits by utilizing localized and selective IC-compatible synthesis, for a fully integrated nano-sensing system. Ultimately, both the nano-sensor element and the signal processing circuits should be fabricated on the same device substrate. The SNWs/CNTs will be synthesized afterwards locally and selectively using MEMS resistive heaters. In order to develop the integration process, we plan to use the 0.35...

BPN352: Micro/Nano Fluidic Interconnector

SangHoon Lee

In this project, near-field electrospinning (NFES) is applied for site-specific, chip-to-chip micro/nano fluidic interconnectors. This fabrication/packaging technology enables off-chip fluidic transportations through fluidic channels of 50nm~5μm in diameter. Near-field electrospinning has the position controllability better than 10μm in contrast to the random deposition of conventional electrospinning.

Project end date: 09/03/08

BPN330: Non-magnetic Micro Heater

Jui-Ming (Ryan) Yang

Non-magnetic heaters are desirable for systems sensitive magnetic fields, such as micromachined gyroscopes using spin-polarized nuclei. The short-term objective of this project is to design and fabricate MEMS resistive heaters that will generate minimum magnetic field while under resistive heating to provide the heating source for the micromachined gyroscope using spin-polarized nuclei. The long-term goal of the project is the integration of the non-magnetic heater with other components to accomplish micromachined gyroscope using spin-polarized nuclei within the magnetic shielding...