PMID-1510294[0] A Glass/silicon Composite Intracortical Electrode Array.
- Describe fabrication of the Utah probe.
- Needles 1.5mm long, 80um in diameter at the base, tapered.
- 10 x 10 array on 400um spacing.
- Impedance 10T ohm, capacitance 50fF
- Old array used diamond dicing saw.
- electrodes were isolated via p-n-p junctions, formed via thermomigration.
- Too clever! These electrodes leaked & had poor yield.
- New method: melt glass into shallow saw kerfs on the backside of a p-doped 1.83mm thick wafer, then remove much of the silicon from the top using the same saw. This produces columns of silicon held together at the base by glass.
- Diamond dicing saw has a kerf of 50um. These things sound awesome.
- Photopatterned aluminum electrode lands on the back.
- Points are made by an acid etch.
- Then plated in metal of some sort
- Followed by polymide insulation (3-6um thick) (rather round from the SEM).
- DC resistance of 10 to 20k.
____References____
[0] Jones KE, Campbell PK, Normann RA, A glass/silicon composite intracortical electrode array.Ann Biomed Eng 20:4, 423-37 (1992) |
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