Micro Needle Insulation via Under-Etch Metal Coating Disruption
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Solution Overview
Problem
Existing methods for electrical insulation of micro-sized needles on a substrate fail to provide effective lateral insulation while maintaining electrical contact through the substrate, requiring costly lithography and etching processes and being unsuitable for high-aspect-ratio topography.
Innovation Solution
A method involving the creation of a via structure with insulating material within the substrate, using an under-etch technique to disrupt metal coating and achieve lateral insulation without lithography and etching, allowing for electrical contact through the substrate while preventing contact with surrounding material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithography and etching processes are used for lateral insulation, then insulation effectiveness is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent extracts the insulation function from complex lithography/etching processes and implements it through a simple oxidation step that grows insulating material directly in the trenches, eliminating the need for multiple patterning and etching operations
Solution Approach 2:
The oxidation process automatically fills the trenches with insulating material based on the existing topography, with the oxidation front self-limiting at the metal coating interface, eliminating the need for precise process control and masking
2Ease of manufacture
If lithography and etching are eliminated, then manufacturing cost is reduced, but insulation precision may worsen
Solution Approach 1:
The patent replaces mechanical lithography and etching processes with a chemical oxidation process that automatically conforms to the substrate topography, achieving precise insulation placement without complex mechanical patterning equipment
Solution Approach 2:
The patent controls the oxidation process parameters (temperature, time, atmosphere) to precisely control the depth and extent of oxidation, ensuring complete trench filling while stopping exactly at the metal coating interface for optimal insulation
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
This approach reduces manufacturing costs by eliminating the need for lithography and etching, provides effective insulation and electrical connectivity, and is applicable to high-aspect-ratio semiconductor substrates, enabling efficient signal routing and device applications.
Implementation Method 1
The oxide is etched away using hydrofluoric acid or other suitable means to expose the metal coating and provide an undercut portion
Implementation Method 2
a metal coating is provided on the substrate and the needle structures by evaporation or sputtering
Implementation Method 3
By virtue of the undercut provided by the wet oxide etch there will be a region that will not be accessible to the sputtered material and thus there will be a disruption in the conductive coating
Data Source
AI summary
A method of providing a metal coating on a substrate (10), and electrically insulating sections/parts of the metal coated substrate from each other. A substrate is provided with an insulating material in the substrate, the insulating first material extending through the thickness of the substrate and protruding above one surface of the substrate. It forms an enclosed section/portion (14) of the substrate. A protective structure (15) is provided on the insulating material such that it covers the entire circumference thereof. The insulating material is selectively etched to create an under-etch (18) under the protective structure. Finally conductive material (19) is deposited to provide a metal coating over the substrate, whereby the under-etch will provide a disruption in the deposited metal coating, thereby electrically insulating the enclosed section from the surrounding substrate.