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

BPNX1046: Multi-Material DLP Printing for 3D Electronics via Selective Deposition (New Project)

David Hahn
Haotian Lu
Ju Young Park
Wenjie (Jeff) Li
Jiayan Zhang
2025

The development of 3D MEMS devices has enabled innovative sensor designs with enhanced functionality, yet conventional fabrication methods often impose geometric and process limitations. This work presents a micro-3D-printed tactile sensor, integrating 3D piezoelectric, capacitive, conductive and dielectric elements with a compliant mechanism to achieve high sensitivity and force decoupling capability. The sensor is fabricated using a multi-material digital light processing (DLP) method, followed by selective metallization to define conductive regions, enabling seamless...

Subtractive Microfluidics in CMOS

Wei-Yang Weng
Alexander Di
Xiang Zhang
Ya-Chen (Justine) Tsai
Yan-Ting Hsiao
Jun-Chau Chien
2024

This paper introduces a microfluidics platform embedded within a silicon chip implemented in CMOS technology. The platform utilizes a one-step wet etching method to create fluidic channels by selectively removing CMOS back-end-of-line (BEOL) routing metals. We term our technique “subtractive” microfluidics, to complement those fabricated with additive manufacturing. Three types of structures are presented in a TSMC I80-nm CMOS chip: (1) passive microfluidics in the form of a micro-mixer and a 1: 64 splitter, (2) fluidic channels with embedded ion-sensitive field-effect transistors (ISFETs...

BPNX1012: Optimization of Integrated Microlens Couplers for Wafer-Scale Packaging

Sirui Tang
Jianheng Luo
Johannes Henriksson
2025

Despite the widespread use of silicon photonics, fiber coupling remains a major challenge in mass production. Our group has demonstrated integrated microlens couplers (IMCs) as an efficient, broadband, and polarization-insensitive solution for wafer-scale fiber-to-chip coupling, with a previously achieved free-space loss of 0.6 dB.

In this project, we are transitioning from polymer-based to hard-material IMCs, fabricating microlens using SiON and utilizing anisotropic etching to transfer the lens pattern from PR to SiON. By optimizing the oxide-to-nitride ratio, we minimized...

BPN984: Large-Area Processable Two-Dimensional Material Films

Naoki Higashitarumizu
Theodorus Jonathan Wijaya
Hyong Min Kim
Shu Wang
Kyuho Lee
2025

Black phosphorus (BP) is a promising material for optoelectronic applications due to its direct bandgap at all thicknesses, and low Auger recombination coefficient at high carrier densities. BP, being a two-dimensional material, lacks scalability, for which techniques for its large-area processing are important. In this work, we find methodologies to utilize this material for large-scale optoelectronic applications.

Project currently funded by: Federal

BPN735: Walking Silicon Microrobots

Yichen Liu
Alexander Alvara
Daniel Lovell
Dang Le
2025

Our goal is to build a family of autonomous silicon robotic insects with actuating, computing, and power capabilities integrated. A silicon-on-insulator (SOI) device is used to house all three components. These robots use electrostatic actuators driving silicon linkages, all fabricated in the device layer of the wafer. By using electrostatic actuation, these actuator linkage systems have the advantage of being low power compared to other methods of actuation on microscale granting robot autonomy through low-power energy harvesting. Computation and communication are carried out with Single...

BPN985: Multimaterial Nanoscale 3D Printing

Daniel Teal
2024

We propose a new multimaterial direct-write printing technique with projected sub-micron resolution. Inorganic nanoparticles (≈1-10nm) of common microfabrication materials are electrically charged, manipulated electromagnetically in vacuum with an ion trap, and shot toward a substrate where they deposit onto a part under construction, similar to PVD methods. To date, we have successfully demonstrated basic multimaterial deposition. Eventually, this ion printing technology could allow rapid prototyping of integrated circuits and MEMS.

Project ended: 12/20/2024

BPNX1018: Free Surface Investigation in Large-Area Projection Micro Stereolithography (New Project)

David Hahn
2024

This project seeks to additively manufacture micro-architected cellular solids in high resolution, large area in hundreds of millimeters, containing millions of unit cells which are defect-free.

Project is currently funded by: Federal

Project ended 08/31/2024

BPN969: Joule Bonding: Localized Solder Bonding for Heterogenous Integration of MEMS

Daniel Teal
2022

We are developing a new MEMS bonding process in which we use extremely carefully controlled resistive heating to make a solder bond with negligible substrate temperature rise and tighter temperature control than in laser bonding; we do this by using the temperature change of the heater resistivity as a temperature sensor for closed-loop control. Previously, we analyzed transient heat flow and showed initial progress toward heater control. Now, we have completed our theoretical analysis with a description of temperature fluctuations due to local inhomogeneities on the chip and how to...

BPN826: Autonomous Flying Microrobots

Nathan Lambert
2022

Among the state of the art academic research on pico air vehicles, the majority has focused on biomimetic flight mechanisms (e.g. flapping wings). This project looks to develop new microfabricated transduction mechanisms and systems for flying microrobots with the goal of opening up the application space beyond that allowed by the industry-standard single quadcoptor. One proposed mechanism, electrohydrodynamic (EHD) force generated via sub-millimeter corona discharge, functions silently and with no moving parts, directly converting ion current to induced airflow. Current work is...

APP38: Microconnector

Helen Holder
2003

Design and fabricate a mechanical interconnect system for use in MEMS and miniaturized applications enabling modular construction of complex 3D structures, and generic enough to be compatible with most designs without modifying original devices.

Project end date: 07/30/03