Neural Probe Manufacturing via Wafer Dicing and Etching
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Solution Overview
Problem
Current methods for manufacturing neural probes from silicon wafers are limited in their ability to efficiently produce probes with precise shapes and dimensions, particularly in terms of shank thickness and microelectrode placement, which affects their performance in recording and stimulating brain activity.
Innovation Solution
A method involving a silicon wafer with multiple layers and etching processes to create neural probes with customizable shanks and microelectrodes, where the shanks can extend from the backend with varying thicknesses and lengths, and microelectrodes are connected to bonding pads via conductive interconnects, allowing for precise shaping and separation of probes from a single wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If wet etching with boron-doped Si stop layer is used to manufacture neural probes, then the shank thickness can be reduced to around 15 μm, but the manufacturing process becomes more complex and time-consuming
Solution Approach 1:
The patent removes the boron-doped Si stop layer step from the manufacturing process, extracting this intermediate layer that previously enabled precise etching control. By eliminating this step, the process becomes simpler while maintaining the ability to achieve thin shank dimensions through direct DRIE control.
Solution Approach 2:
The patent replaces the chemical etching mechanism (wet etching with boron stop layer) with a mechanical/physical etching mechanism (DRIE). This substitution allows for direct control of etching depth and profile through process parameters rather than relying on chemical reactions and stop layers, simplifying the overall manufacturing process.
2Ease of manufacture
If DRIE is used to manufacture Si probes without boron etch stop, then the manufacturing process is simplified, but control over shank thickness precision may be reduced
Solution Approach 1:
The patent utilizes DRIE process parameters (etch rate, depth control, side wall angle control) to achieve precise shank thickness without requiring a stop layer. By carefully controlling etching depth and rate, the desired precision is maintained while simplifying the manufacturing process.
3Productivity
If multiple neural probes are patterned on one side of a silicon wafer and separated by dicing the opposite side, then productivity increases, but the complexity of aligning dicing lanes with probe patterns increases
Solution Approach 1:
The patent transitions from patterning and dicing on the same surface to patterning on one side and dicing on the opposite side of the wafer. This dimensional approach allows multiple probes to be processed simultaneously while maintaining alignment through the wafer thickness, increasing productivity without excessive alignment complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the production of neural probes with precise dimensions and configurations, enhancing their ability to record and stimulate brain activity effectively, suitable for clinical and research applications such as seizure detection and assisting paralyzed patients.
Implementation Method 1
etching through said first and second insulating layers and a top portion of the top side of the silicon wafer in a pattern that corresponds to the desired shape of the neural probe
Data Source
AI summary
A method of manufacturing a plurality of neural probes from a silicon wafer in which after neural probes are formed on one side of a silicon wafer, the other side of the silicon wafter is subject to a dicing process that separates and adjusts the thickness of the neural probes.