Integration of Trench-Isolated Through-Wafer Interconnects with 2D Capacitive Micromachined Ultrasonic Transducer Arrays.
This paper presents a method to provide electrical connection to a 2D capacitive micromachined ultrasonic transducer (CMUT) array. The interconnects are processed after the CMUTs are fabricated on the front side of a silicon wafer. Connections to array elements are made from the back side of the substrate via highly conductive silicon pillars that result from a deep reactive ion etching (DRIE) process. Flip-chip bonding is used to integrate the CMUT array with an integrated circuit (IC) that comprises the front-end circuits for the transducer and provides mechanical support for the trench-isolated array elements. Design, fabrication process and characterization results are presented. The advantages when compared to other through-wafer interconnect techniques are discussed.
Edward L. Ginzton Laboratory, Stanford University, Stanford, CA 94305 Email: xzhuang@stanford.edu.
Xuefeng
X
Zhuang
Arif S
AS
Ergun
Yongli
Y
Huang
Ira O
IO
Wygant
Omer
O
Oralkan
Butrus T
BT
Khuri-Yakub