Noble Metal MEMS Resonator Patterning for Liquid-Phase Functionalization
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Solution Overview
Problem
Existing acoustic resonator devices face challenges in operating effectively in liquid environments due to dimensional tolerances issues with microarray spotting, leading to reduced sensor response and non-specific binding, especially with reactive metal electrodes prone to corrosion, and require cost-effective and repeatable manufacturing methods.
Innovation Solution
A micro-electromechanical system (MEMS) resonator device with a bulk acoustic wave structure, featuring a piezoelectric material between electrodes, a hermeticity layer, an interface layer of gold or noble metals, and a self-assembled monolayer, allowing for precise patterning and functionalization material placement to overcome alignment and overprinting challenges, and enabling operation in liquid without compromising performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If microarray spotting is used for functionalization material placement, then device manufacturing is simplified, but dimensional tolerance deteriorates leading to alignment and overprinting challenges
Solution Approach 1:
The patent introduces a self-assembled monolayer (SAM) as an intermediary layer between the reactive metal electrode and the functionalization material. This SAM layer serves as a mediator that enables precise patterning and functionalization material placement while avoiding the dimensional tolerance issues of direct microarray spotting on reactive metal surfaces. The SAM provides a stable platform that maintains alignment precision during the functionalization process.
Solution Approach 2:
The patent applies the self-assembled monolayer formation as a preliminary action before functionalization material deposition. By pre-forming the SAM layer on the reactive metal electrode, the system establishes a stable surface that enables subsequent precise patterning and functionalization material placement, thereby preventing alignment and overprinting challenges that would occur with direct spotting.
2Reliability
If reactive metal electrodes are used, then device performance is improved, but corrosion resistance deteriorates in liquid environments
Solution Approach 1:
The self-assembled monolayer acts as a protective intermediary between the reactive metal electrode and the liquid environment. This SAM layer preserves the electrical and acoustic performance benefits of reactive metal electrodes while providing corrosion resistance by preventing direct contact between the metal and corrosive liquid species.
Solution Approach 2:
The patent employs a thin self-assembled monolayer that can be easily formed and regenerated. This disposable-like protective layer provides effective corrosion protection without compromising the underlying reactive metal electrode's performance, and can be reformed if needed to maintain long-term device reliability.
3Measurement precision
If functionalization material is deposited to enhance sensor response, then detection sensitivity is improved, but non-specific binding increases
Solution Approach 1:
The patent uses the self-assembled monolayer to enable localized and controlled functionalization material deposition. By patterning the SAM layer, the functionalization material is placed only in specific regions with precise dimensional tolerance, thereby enhancing sensor response in the active area while minimizing non-specific binding in surrounding areas.
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
The solution enhances the dimensional tolerance of functionalization material placement, reduces non-specific binding, and maintains device performance in liquid environments, addressing the limitations of existing technologies while providing a cost-effective and repeatable manufacturing process.
Implementation Method 1
a bulk acoustic wave resonator structure arranged over at least a portion of the substrate and including a piezoelectric material
Implementation Method 2
a self-assembled monolayer arranged over at least a portion of the interface layer
Data Source
AI summary
A micro-electrical-mechanical system (MEMS) resonator device includes a top side electrode overlaid with an interface layer including a material having a surface (e.g., gold or a hydroxylated oxide) that may be functionalized with a functionalization (e.g., specific binding) material. The interface layer and/or an overlying blocking layer are precisely patterned to control locations of the interface layer available to receive a self-assembled monolayer (SAM), thereby addressing issues of misalignment and oversizing of a functionalization zone that would arise by relying solely on microarray spotting. Atomic layer deposition may be used for deposition of the interface layer and/or an optional hermeticity layer. Sensors and microfluidic devices incorporating MEMS resonator devices are also provided.