title: Silicon ribbon cables for chronically implantable microelectrode arrays.
abstract: This paper describes the design, fabrication, and testing of miniature ultraflexible ribbon cables for use with micromachined silicon microprobes capable of chronic recording and/or stimulation in the central nervous system (CNS). These interconnects are of critical importance in reliably linking these microelectrodes to the external world through a percutaneous connector. The silicon cables allow the realization of multilead, multistrand shielded local interconnects that are extremely flexible and yet strong enough to withstand normal handling and surgical manipulation. Cables 5 microns thick, 1-5 cm long, and from 60 to 250 microns wide have been fabricated with up to eight leads. The series lead resistance is typically 4 k omega/cm for polysilicon and 500 omega/cm for tantalum, with shunt capacitance values of 5-10 pF/cm and an interlead capacitance below 10 fF/cm. Soak tests in buffered saline performed under electrical and mechanical stress have been underway for over three years and show subpicoampere leakage levels. Silicon microprobes with built-in ribbon cables have remained functional for up to one year in the guinea pig CNS, recording driven single-unit activity and maintaining impedance levels in the 1-7 M omega range.
authors.affiliation: Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor 48109.
authors.forename: J F
authors.initials: JF
authors.lastname: Hetke
authors.forename: J L
authors.initials: JL
authors.lastname: Lund
authors.forename: K
authors.initials: K
authors.lastname: Najafi
authors.forename: K D
authors.initials: KD
authors.lastname: Wise
authors.forename: D J
authors.initials: DJ
authors.lastname: Anderson
mesh_terms: D000818:Animals; D002490:Central Nervous System; D017097:Electric Impedance; D004567:Electrodes, Implanted / Q000592:standards*; D004867:Equipment Design; D006168:Guinea Pigs; D008422:Materials Testing; D008839:Microelectrodes / Q000592:standards*; D012825:Silicon; D013314:Stress, Mechanical; D013997:Time Factors
chemical_list: D012825:Silicon