Stepped Metal Sensing Structures for Analyte Detection
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Solution Overview
Problem
Existing sensing structures, such as surface plasmon resonance structures, have insufficient sensitivity for analyte detection.
Innovation Solution
A sensing structure with a substrate and a metal layer featuring a first portion on the substrate and a second portion in a recess, with a gap between them ranging from 20 nm to 100 nm, and a sensing chip comprising a filter array, carrier layer, light-blocking layer, and polarizer, formed through anisotropic etching processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional sensing structures are used, then the structure is simple and easy to manufacture, but the sensitivity for analyte detection is insufficient
Solution Approach 1:
The metal layer is segmented into multiple portions (first portion, second portion, third portion) at different heights above the substrate, creating a stepped configuration. This segmentation allows each portion to interact with light differently, enhancing the sensing capability while maintaining a manufacturable structure through selective etching processes.
Solution Approach 2:
The invention introduces vertical dimensionality by creating portions of the metal layer at different heights (z-direction) rather than just in the planar direction. The first portion extends highest, the second portion is intermediate, and the third portion is lowest, creating a three-dimensional stepped structure that enhances light-matter interaction for improved sensitivity.
2Measurement precision
If the metal layer is made thicker to improve detection, then the sensitivity increases, but the manufacturing precision becomes more difficult to control
Solution Approach 1:
A mask layer is formed beforehand on the substrate before depositing the metal layer. This pre-formed mask serves as a template that guides the subsequent metal deposition and etching processes, ensuring that the metal portions are deposited in the correct locations and heights, thereby facilitating precise gap formation without requiring extreme manufacturing precision.
Solution Approach 2:
The invention controls the gap dimension (20-100 nm) by adjusting deposition parameters and etching conditions rather than relying solely on mechanical precision. By changing the physical parameters of the fabrication process (deposition thickness, etch selectivity, mask thickness), the gap size is precisely controlled to optimize sensing performance while remaining manufacturable.
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 structured sensing chip enhances sensitivity by improving the detection of wavelength shifts, allowing for more precise analyte detection.
Implementation Method 1
Sensing structures such as surface plasmon resonance (SPR) structures are widely used to sense and detect analytes
Data Source
AI summary
A sensing structure, a sensing chip including the sensing structure, and method for forming the sensing structure are provided. The sensing structure includes a substrate and a metal layer. The substrate has a first recess. The metal layer is disposed on the substrate. The metal layer includes a first portion and a second portion. The first portion is disposed on a top surface of the substrate. The second portion is disposed in the first recess. The second portion includes a base portion and a protruding portion disposed on the base portion and extending away from the substrate. A gap is between the first portion and the protruding portion and surrounds the protruding portion, and the gap is in a range of 20 nm to 100 nm.