Weekly Report

Renjie ChenSupervisor: Shadi A. Dayeh

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Integrated Electronics and Bio-interfaces Lab

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Summary

• In the past week, I was working on the project of high-density neural probes.

• There were some problems in the fabrication process, related to the nickel silicide bonding and Si RIE/ICP etching.

• My target was to: (1) modify the nickel silicide bonding conditions

(2) test new metal stacking layers

(3) push new samples ready for neural culture/measurement

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Integrated Electronics and Bio-interfaces Lab

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Processing Flow

* Process designed by Prof. Shadi and Dr. Yoontae, and figures adapted from Dr. Yoontae’s presentation

Problems to solve

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Integrated Electronics and Bio-interfaces Lab

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NiSix Bonding Modification

Possible Solutions

1st Problem:

Possible Reason

Ti/Ni/Ti/Ni = 30/350/30/50 nmStep height = 870 nm

Ti/Pd/Ti/Ni = 30/60/30/400 nmStep height = 640 nm

Ti/Ni/Ti/Ni = 30/50/30/350 Ti/Ni/Ti/Ni = 30/50/30/350 Step height = 570 nm

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Integrated Electronics and Bio-interfaces Lab

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Nickel silicide Ni tape

Possible Reason

Possible Solutions • Shorten the Bonding time or lower the bonding temperature to have

sufficient Ni remained.

• Try multiple Metal layer stacking.Previous metal stacking: Ti/Pd/Ti/Ni = 30nm/60nm/30nm/400nmNew metal stacking: Ti/Pd/Ti/Ni/Ti/Ni =

30nm/60nm/30nm/200nm/30nm/200nm

2nd Problem:

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Integrated Electronics and Bio-interfaces Lab

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Edge

Ti/Pd/Ti/Ni = 30nm/60nm/30nm/400nm

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Integrated Electronics and Bio-interfaces Lab

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Ti/Pd/Ti/Ni/Ti/Ni = 30nm/60nm/30nm/200nm/30nm/200nm

Edge

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Integrated Electronics and Bio-interfaces Lab

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Metal Stacking

Ti/Pd/Ti/Ni/Ti/Ni = 30nm/200nm/50nm/50nm

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Integrated Electronics and Bio-interfaces Lab

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Plan

1. Samples send back to UCSD for thinning/pillar etching7 Samples with old metal stacking (Ti/Pd/Ti/Ni) finished

-- 5 samples bonded with 90um Si, for Si thinning -> send back-- 2 samples bonded with 10um Si, for pillar etching -> directly use for

device9 Samples with new metal stacking (Ti/Pd/Ti/Ni/Ti/Ni) in preparation

-- 7 samples to be bonded with 90um Si, for Si thinning -> send back-- 2 samples to be bonded with 10um Si, for pillar etching -> directly use

for device

2. During waiting for samples coming back-- work on Ni-InGaAs project-- Cory’s EBL sample, may take some time to calibrate the off-set-- Farid’s Photomask has finished, will be mailed together with my samples