A high-yield fabrication process for silicon neural probes.

Area of Science:

• Neuroscience
• Materials Science
• Electrical Engineering

Background:

• Simultaneous monitoring of neural activity requires advanced silicon microelectrodes.
• Existing fabrication methods, particularly reactive-ion etching combined with KOH etching, face challenges during the device release wet-etching step, leading to low yields and imprecise structures.

Purpose of the Study:

• To introduce a modified wet-etching sidewall-protection technique for high-yield fabrication of well-defined silicon microelectrode probe structures.
• To address the breakdown issue in existing fabrication processes during the wet-etching stage.

Main Methods:

• Utilized a Teflon shield and low-pressure chemical vapor deposition (LPCVD) silicon nitride for sidewall protection.
• Implemented a micro-tab system to hold individual probes to a central scaffold, ensuring uniform anisotropic potassium hydroxide (KOH) etching.

Main Results:

• Achieved high-yield fabrication of well-defined silicon probe structures.
• Successfully prevented device loss during the critical wet-etching process.
• Demonstrated improved accuracy in fabrication and an enhanced mechanical profile of the microelectrodes.

Conclusions:

• The developed sidewall-protection technique offers a robust and simple solution for fabricating high-quality silicon microelectrodes.
• This method overcomes limitations of previous techniques, enabling reliable production of microelectrodes essential for advanced neural monitoring.
• The improved fabrication process contributes to more accurate neural recordings and better device performance.