Integrated-circuit microprobe (Wise, 1970)

One-line verdict: The paper that moved extracellular electrodes from hand-made wires to photolithography. Every silicon shank probe in this catalog descends from this idea.

Quick tags: Recording · Intracortical · Published: 1970

Overview

What it is: A multielectrode microprobe built with integrated-circuit fabrication techniques. Gold electrodes sit on a silicon carrier and project about 50 µm beyond it, so the tips can get close to active neurons.

How the recording sites are defined: The electrodes are covered with a thin (0.4 µm) layer of silicon dioxide. The oxide is removed at the tips with high-resolution photoengraving, which sets the recording area precisely.

Why it matters: The authors present it as a way around the problems of conventional hand-made microelectrodes. Controlled geometry and batch fabrication are what later probes, including the Neuropixels shank, rely on.

Lineage: Kensall Wise later started silicon neural probe work at the University of Michigan (Michigan’s EECS profile of Wise describes him joining in 1974 to expand his doctoral research on silicon micromachining for neural probes).

Spec Card Grid

Identity

• Authors: Kensall D. Wise, James B. Angell, Arnold Starr
• Published: 1970 (title: “An Integrated-Circuit Approach to Extracellular Microelectrodes”)

Geometry & Architecture

• Electrodes: gold, on a silicon carrier
• Projection beyond carrier: about 50 µm
• Insulation: 0.4 µm silicon dioxide, opened at the tips by photoengraving

Evidence and limits

• Not covered here: recording results, channel counts and later probe dimensions, which are in the paper and its successors

References

• Wise KD, Angell JB, Starr A. An integrated-circuit approach to extracellular microelectrodes. 1970. https://escholarship.org/uc/item/5374x0rj
• University of Michigan EECS. Kensall D. Wise profile. https://eecsnews.engin.umich.edu/wp-content/uploads/sites/2/2019/11/kensall-wise-michigan-mems-and-microsystems.pdf