CMUT Probe Die Layout With Integrated Interposer and Passive Mounting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Miniaturization of ultrasound probes for advanced diagnostic purposes, such as cardiac investigations and surgery, is challenging due to the need for compactness and rigidity while incorporating significant signal processing capability and passive components like decoupling capacitors, which existing technologies find difficult to reconcile.
Innovation Solution
An integrated circuit die with a substrate featuring a sensor region for ultrasound transducer cells and an interposer region providing conductive connections and mounting pads for passive components, eliminating the need for a separate interposer and minimizing parasitic resistance and capacitance, thereby achieving a compact and reliable connection scheme.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If separate interposer and PCB are used to provide conductive connections and mount passive components, then connection functionality is achieved, but device size and complexity increase
Solution Approach 1:
The patent merges the interposer and PCB into a single integrated substrate structure. The substrate provides both conductive connections for the CMUT device and mounting capability for passive components, eliminating the need for separate interposer and PCB assemblies. This integration directly reduces the overall probe volume and simplifies the structural complexity.
Solution Approach 2:
The substrate is designed to perform multiple functions simultaneously: providing conductive connections for the CMUT device, serving as a mounting platform for passive components, and offering mechanical support. This multi-functionality consolidates what would traditionally require separate components, thereby reducing device size and complexity.
2Reliability
If passive components are mounted on separate PCB, then protection from supply voltage fluctuations is achieved, but parasitic resistance and capacitance increase
Solution Approach 1:
By integrating the passive components directly onto the substrate with the CMUT device, the patent minimizes the length of interconnections. This reduces parasitic resistance and capacitance while maintaining the protective function against supply voltage fluctuations through proper circuit design on the integrated substrate.
3Volume of moving object
If miniaturization is pursued for advanced diagnostic probes, then probe compactness improves, but integration of signal processing capability and passive components becomes difficult
Solution Approach 1:
The patent combines the CMUT device, signal processing circuitry, and passive components onto a single integrated substrate. This consolidation achieves miniaturization by eliminating the need for separate assemblies, while the integrated architecture manages complexity through unified design and reduced interconnection requirements.
Solution Approach 2:
The patent utilizes three-dimensional integration strategies, including vertical stacking and multi-layer substrate design, to accommodate multiple functional elements within a compact footprint. This approach to miniaturization reduces the probe size while maintaining all necessary functionality by efficiently utilizing available space in multiple dimensions.
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 configuration results in a more compact ultrasound transducer probe with improved reliability and sensitivity, suitable for small form factor applications, and enhances the probe's ability to handle fluctuations in supply voltage, protecting internal components from power-related issues.
Implementation Method 1
CMUT (capacitive micromachined ultrasound transducer) elements. Vibration of the CMUT membrane can be triggered by applying pressure (for example using ultrasound) or can be induced electrically. In reception mode, changes in the membrane position cause changes in electrical capacitance, which can be registered electronically. In transmission mode, applying an electrical signal causes vibration of the membrane.
Implementation Method 2
passive components such as decoupling capacitors that for instance protect the various circuits from fluctuations in the supply voltage
Data Source
AI summary
An integrated circuit die is disclosed that comprises a substrate defining a plurality of circuit elements; a sensor region on the substrate, the sensor region comprising a layer stack defining a plurality of CMUT (capacitive micromachined ultrasound transducer) cells; and an interposer region on the substrate adjacent to the sensor region. The interposer region comprises a further layer stack including conductive connections to the circuit elements and the CMUT cells, the conductive connections connected to a plurality of conductive contact regions on an upper surface of the interposer region, the conductive contact regions including external contacts for contacting the integrated circuit die to a connection cable and mounting pads for mounting a passive component on the upper surface. A probe including such an integrated circuit die an ultrasound system including such a probe are also disclosed.