Bulk Acoustic Resonator Packaging for Dense Fluidic Sensor Arrays
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Solution Overview
Problem
Existing methods for manufacturing bulk acoustic wave (BAW) sensor arrays face challenges in achieving high density due to long electrical leads and limited fluidic channel height, making it difficult to integrate electrical and fluidic connections effectively on the same side of the BAW die.
Innovation Solution
A method involving flip chip mounting and substrate removal to expose electrodes, combined with acoustic energy management structures like air cavities or mirrors, allows for efficient electrical connection to a printed circuit board while maintaining a low fluidic channel height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple rows of resonators are placed in the fluidic pathway to increase sensor array density, then the sensor array density is improved, but the electrical lead length increases making it difficult to address high density resonator sensor arrays
Solution Approach 1:
The patent moves electrical connections from the same plane as fluidic connections to the opposite side of the BAW die. This spatial reorganization in a different dimension (through the thickness of the die) allows electrical leads to be short while still accommodating high-density sensor arrays in the fluidic pathway.
Solution Approach 2:
The patent separates electrical connections and fluidic interfaces onto opposite sides of the BAW die. This segmentation allows independent optimization of electrical lead length and fluidic channel layout, enabling high-density sensor arrays without compromising electrical connection efficiency.
2Reliability
If the fluidic channel height is increased to accommodate electrical connections on the same side, then the electrical connection reliability is improved, but the fluidic channel height increases reducing device compactness
Solution Approach 1:
The patent relocates electrical connections to the opposite side of the die from fluidic interfaces, utilizing the third dimension (die thickness) to resolve the spatial conflict. This allows both electrical and fluidic connections to be optimized independently without increasing overall device height.
3Device complexity
If electrical and fluidic connections are integrated on the same side of the BAW die, then the device complexity is reduced, but the manufacturing precision required increases due to the difficulty of addressing high density resonator arrays
Solution Approach 1:
The patent divides the die into two functional sides: one for electrical connections and one for fluidic interfaces. This segmentation simplifies the manufacturing process by allowing each side to be optimized independently, reducing the precision requirements for integrating both connection types on the same side.
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 fabrication of high-density BAW sensor arrays with short electrical leads and reliable fluidic interfaces, facilitating efficient biosensing applications.
Implementation Method 1
a piezoelectric material over the first electrode, the second conductive material over the piezoelectric material
Implementation Method 2
acoustic energy management structure over a first side of the bulk acoustic wave resonator
Data Source
Figure 1A~1G
Figure 1H~1I
Figure 1J
AI summary
Methods of fabricating a bulk acoustic wave resonator structure for a fluidic device can include a first step of disposing a first conductive material over a portion of a first surface of a substrate to form at least a portion of a first electrode; then, a piezoelectric material may be disposed over the first electrode; next, a second conductive material can be disposed over the piezoelectric material to form at least a portion of a second electrode; an acoustic energy management structure is then disposed over a first side of the bulk acoustic wave resonator; next a third conductive material is disposed over a portion of the second conductive material that extends beyond the bulk acoustic wave resonator; finally a portion of the second surface of the substrate is removed to expose a chemical mechanical connection at the first electrode at a second side of the bulk wave acoustic resonator.