Monolithic Proximity Sensor Coil Layout for 3 mm Detection
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Solution Overview
Problem
Existing proximity sensors struggle to reliably detect electrically conductive or magnetic targets at distances greater than 3 mm due to limitations in coil size and substrate area, leading to increased sensor size and cost.
Innovation Solution
A monolithic integrated proximity sensor device with a single semiconductor substrate, featuring a transmitter coil and receiver coil designed within the interconnection stack, allowing for efficient use of space by placing components inside the coil peripheries, and utilizing a CMOS process to achieve reliable detection up to 3 mm with reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the coil size and substrate area are increased to improve detection distance, then the detection distance is improved, but the sensor size and cost increase
Solution Approach 1:
The receiver coil is positioned inside the inner periphery of the transmitter coil, creating a nested configuration where the receiver coil's outer periphery is contained within the transmitter coil's inner periphery. This nesting allows both coils to share the same spatial envelope, maximizing the magnetic field utilization and detection distance without increasing the overall sensor footprint.
Solution Approach 2:
The patent utilizes multiple metal layers in the interconnection stack to form the coils, transitioning from a two-dimensional planar arrangement to a three-dimensional layered structure. This allows the transmitter and receiver coils to be stacked vertically with electrical insulation between them, enabling compact integration while maintaining effective detection area and distance.
2Measurement precision
If the coil size and substrate area are increased to improve detection distance, then the detection distance is improved, but the manufacturing cost increases
Solution Approach 1:
The transmitter coil and receiver coil are integrated into a single monolithic semiconductor substrate using the same interconnection stack and manufacturing process. This merging of both coils and their supporting infrastructure into one unified structure eliminates the need for separate substrates or assembly steps, reducing manufacturing complexity and cost while achieving the required detection distance.
Solution Approach 2:
The interconnection stack serves multiple functions simultaneously: it provides electrical insulation between the transmitter and receiver coils, acts as the structural substrate for both coils, and enables the monolithic integration of the entire sensor. This multi-functionality reduces the number of separate components and manufacturing steps required, lowering overall production cost.
3Reliability
If components are placed outside the coil peripheries to avoid interference, then component reliability is improved, but the substrate area increases
Solution Approach 1:
The receiver coil is nested inside the transmitter coil's inner periphery, allowing both coils to occupy the same spatial envelope. This nested arrangement maximizes the use of the substrate area, enabling all components to be integrated within a compact footprint without requiring additional space outside the coil peripheries.
Solution Approach 2:
By utilizing multiple metal layers in the interconnection stack, the patent vertically separates the transmitter and receiver coils while maintaining their horizontal overlap. This three-dimensional arrangement allows components to be positioned within the coil peripheries in the horizontal plane while maintaining electrical insulation and operational reliability through vertical separation.
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 enables compact, cost-effective detection of targets up to 3 mm distance with reduced power consumption, overcoming the limitations of traditional sensor designs by optimizing coil placement and substrate use.
Implementation Method 1
sensing a dynamic magnetic field generated by a transmitter coil conducting an alternating current
Implementation Method 2
A characteristic of the magnetic field is changed depending on the position of a movable object
Implementation Method 3
sensing a dynamic magnetic field generated by a transmitter coil conducting an alternating current
Data Source
AI summary
A monolithic integrated proximity sensor device includes a semiconductor substrate with an active surface with at least one active or passive component or bond pad; an interconnection stack having a plurality of at least two metal layers; at least a first transmitter coil having a first spiral course with at least three turns formed in at least one or at least two metal layers and defining the first region having a first inner and outer periphery; at least a first receiver coil having a second spiral course with at least three turns formed in at least one or at least two metal layers and defining a second region having a second inner and outer periphery. At least one component or bond pad is located inside the first or second inner periphery.