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

BPN331: Plastically Self-Alligned Micromirrors

TeHsi Lee

This project aims to use the plastic deformation of silicon as the key process to make Angular Vertical Comb-drive (AVC) actuators using a simple 3-mask process and yet providing versatility for the various applications.

Project end date: 02/14/06

RM8: Stiction in MEMS

Brian Bush

Electrostatic forces, due to trapped charge or applied voltage, can lead to unwanted adhesion in MEMS devices. We wish to use various techniques, including Electronic Force Microscopy (EFM) and Cantilever Beam Arrays (CBA), to characterize the effect of surface modifications on the electrical properties of MEMS components and to better understand the forces that cause stiction. This knowledge will enable one to develop novel surface modifications or self-assembling monolayers that are specifically designed to combat stiction due to electronic forces.

Project end date:...

KSJP33: Silicon on Insulator Microassembly

Subramaniam Venkatraman

To develop actuated 2-axis micromirrors and walking microrobots using a pick-and-place assembly process. Simple fabrication processes have a high fabrication yield and quicker design cycles than complex processes. The quest to minimize process complexity has led us to a single-mask Deep Reactive Ion Etch (DRIE) using Silicon on Insulator (SOI) wafers. After release, these parts are broken free from the device layer of the SOI wafer using grippers fabricated in the same single-mask process, rotated 90 degrees out-of-plane, and then assembled with other parts (figure 1). With this...

BPN309: SAM for MEMS Packaging/Fuel Cell Applications

SangHoon LEE

In this project, Self-Assembled Monolayer (SAM) is investigated for possible MEMS packaging and fuel cell applications.

Project end date: 07/31/06

BPN318: SiGe Processing for the Fabrication of a Floating Electromechanical System (FLEMS) Gyroscope

Marie-Ange Eyoum
David Garmire

The long term range of this project was to demonstrate fabrication and control of a potential integrated FLEMS (Floating Electromechanical) Gyro using SiGe MEMS Technology. The sensor system is comprised of a disk-shaped proof mass that is to be electrostatically suspended between sense and drive electrodes located above, below, and at the sides of the disk. An attractive feature of this design is that the proof mass is not structurally linked via suspension, so that mechanical losses associated with anchors are eliminated

Project end date: 08/02/06

RTH35: Novel SiGe Processes for Electrostatically Actuated MEMS Resonators

Carrie Low

As an alternative material for surface micromachining, polycrystalline silicon-germanium (poly-SiGe) has comparable processes and material properties to polycrystalline silicon (poly-Si). Its low processing temperature is the major advantage of poly-SiGe as it enables post-CMOS integration of MEMS. This modular approach to MEMS integration is an attractive route to higher performance and lower cost microsystems.

Project end date: 01/24/07

APP77: MEMS Strain Gauge on Steel: Elastic Encapsulation

Robert G. Azevedo

The MEMS strain gauge on steel project aims to design a MEMS strain gauge that can be bonded directly to steel and accurately measure strain in small strain fields (gauge length of 1 mm or less). Encapsulation of the MEMS strain gauge, in contrast to microelectronics or inertial force sensor packaging, requires that the package be a mechanical transducer of the measurand to the sense elements. To meet the objective of hermetic, minimally-aliasing encapsulation of the strain gauge, we propose an elastic, wafer-level solution.

Project end date: 01/26/07

RM5/RTH: Silicon carbide process development and characterization for harsh-environment sensors

Jingchun Zhang
Carlo Carraro

Silicon carbide (SiC) is a wide band gap semiconductor with extraordinary properties and has attracted considerable attention for high temperature electronics. Recently, this material is being pursued for microelectromechanical systems (MEMS) applications in harsh environments. The goal of this project is to develop a series of SiC-based sensors and to characterize them for harsh environments. In order to achieve thisgoal, a series of microfabrication technologies including low-temperature CVD, reactive ion etching, and metalization of poly-SiC films need to be developed. In addition...

LWL24: Rapid Bonding of MEMS Strain Gauge to Steel

Brian D. Sosnowchik
Ko-Min Liao

A rapid and reliable bonding method is needed to bond MEMS strain gauges to steel. The MEMS strain gauge is to be bonded to the manufactured steel after all other steel treatment steps have been completed; hence the bonding method must be kept at low temperature to prevent any thermal damage to the steel composition. In addition, the bonding method must not introduce high residual strains, which would cause error in strain gauge measurements. The strain gauge to steel bond must also have the ability to survive several years in a wide working temperature range (-60oC to 150oC) in an...

RTH42: Nanowire-Coupled Resonators

Noel Arellano

We have developed fabrication processes to create top down nanowire coupled resonators. The critical dimensions were defined using a combination of iline lithography, photoresist ashing techniques and focused ion beam trimming. Nanowires are used as mechanical elements to demonstrate low velocity and maximum velocity coupling. We have also demonstrated an bottom up/ top down integrated fabrication process. Features for the top down segment of the fabrication process are aligned to (111) flat on a (110) SOI wafer. A gold based galvanic displacement method selectively deposits catalyst...