On-Chip Capacitor Integration in Magnetic Sensor Subsystems
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Solution Overview
Problem
Existing magnetic sensors require external decoupling capacitors to enhance EMC and reduce long-wire noise, which increase costs and package size due to the need for additional components and circuit boards.
Innovation Solution
Integration of on-chip capacitors formed by conductive layers and a dielectric layer over a substrate within the sensor, eliminating the need for external decoupling capacitors and allowing for capacitive impedance in magnetic sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external decoupling capacitors are used, then EMC protection and noise reduction are improved, but device complexity and package size increase
Solution Approach 1:
The patent merges the decoupling capacitor function with the sensor die by forming an on-chip capacitor using conductive layers and dielectric layers integrated into the sensor structure. This eliminates the need for separate external capacitor components and their associated mounting hardware, thereby reducing package size while maintaining EMC protection and noise reduction functionality.
Solution Approach 2:
The sensor die is designed to perform multiple functions: it serves as both the sensing element and the substrate for the decoupling capacitor. The conductive layers that would otherwise be separate components are integrated onto the sensor die, making the die universal for both sensing and decoupling purposes, thus reducing overall device complexity.
2Reliability
If external decoupling capacitors are used, then EMC protection is improved, but manufacturing cost increases
Solution Approach 1:
By combining the capacitor fabrication process with the sensor manufacturing process, the patent eliminates the need for separate capacitor component procurement, placement, and assembly steps. The conductive and dielectric layers are deposited and patterned using the same semiconductor fabrication techniques already employed for the sensor, thereby reducing manufacturing cost while maintaining EMC protection.
Solution Approach 2:
The sensor die itself provides the decoupling function through integrated conductive and dielectric layers, eliminating the need for external capacitor components. This self-service approach reduces the bill of materials and simplifies the manufacturing supply chain, thereby reducing overall manufacturing cost.
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 solution reduces costs and package size by providing effective EMC protection and capacitance within the sensor, suitable for various applications including anti-lock brake sensors and other vehicle systems, while maintaining a breakdown voltage of at least 50V and capacitance ranging from 100 pF to 1,500 pF.
Implementation Method 1
first and second conductive layers and a dielectric layer formed over a substrate... form a capacitor
Implementation Method 2
a dielectric layer disposed between the first and second conductive layers such that the first and second conductive layers and the dielectric layer form a capacitor
Data Source
AI summary
An integrated circuit comprises a plurality of layers including a first substrate with an on chip capacitor and a second substrate. In one embodiment, the second substrate has an on chip capacitor. The first and/or second substrate can include a sensor element, such as a magnetic sensor element.