Integrated Hall Sensor Coil Layout for Uniform On-Chip Calibration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing Hall sensors face challenges in achieving uniform and homogeneous magnetic field induction for final test and calibration, particularly for vertical Hall sensors, due to limitations in integrated coil design and self-heating issues, which impact manufacturing efficiency and cost.
Innovation Solution
A Hall integrated sensor is manufactured using CMOS-compatible processes, incorporating a coil structure that surrounds the vertical Hall element to induce a nearly homogeneous magnetic field, achieved through a combination of metal layers and through silicon vias, ensuring the Hall plate is entirely within the coil's interior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If an integrated coil is used for final test and calibration of vertical Hall sensors, then the magnetic field induction efficiency is improved, but the self-heating of the Hall sensor element increases
Solution Approach 1:
The patent introduces an intermediary cooling structure between the integrated coil and the Hall sensor element. This cooling structure acts as a thermal mediator that conducts heat away from the sensor element while allowing the coil to generate the necessary magnetic field, thus resolving the contradiction between efficient magnetic field induction and self-heating reduction
Solution Approach 2:
The patent segments the integrated coil into multiple smaller coil sections that are distributed around the Hall sensor element. This segmentation allows for reduced current density in each individual coil section, thereby reducing self-heating while maintaining overall magnetic field induction efficiency through the combined effect of all sections
2Force
If the coil current is increased to achieve larger magnetic fields, then the magnetic field strength is improved, but the electromigration performance of CMOS metal layer deteriorates
Solution Approach 1:
The patent divides the coil into multiple segments distributed around the Hall sensor element. Each segment carries a portion of the total current, which reduces the current density and electromagnetic stress on individual CMOS metal layers while collectively generating the required strong magnetic field through superposition
Solution Approach 2:
The patent transitions from a planar coil configuration to a three-dimensional distributed coil structure surrounding the Hall sensor element. This spatial arrangement in multiple dimensions allows for more efficient magnetic field generation with lower current requirements, reducing electromigration risk in the CMOS metal layers
3Ease of manufacture
If a standard metal layer is used for coil formation, then the manufacturing process is simplified, but the magnetic field homogeneity in the Hall plate deteriorates
Solution Approach 1:
The patent employs a composite coil structure combining multiple metal layers with different electrical and magnetic properties. This composite approach allows optimization of both manufacturability (using standard CMOS metal layers) and magnetic field homogeneity (through strategic layer configuration and material selection), resolving the contradiction between ease of manufacture and manufacturing precision
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 design enables efficient and uniform magnetic field induction for both horizontal and vertical Hall sensors, reducing the need for external calibration and lowering manufacturing costs by integrating the coil directly on the sensor chip.
Implementation Method 1
a coil structure surrounding a vertical Hall element to induce a nearly homogeneous magnetic field in the Hall plate
Implementation Method 2
vertical Hall elements, which sense the strength of the magnetic field in a direction lying in the plane of the silicon surface
Data Source
AI summary
An integrated Hall sensor is provided with: a main wafer (10) of semiconductor material having a substrate (101) with a first surface (101a) and a second surface (101b), opposite to the first surface (101a) along a vertical axis (y); Hall sensor terminals (1, 2, 3, 4; 1′, 2′, 3′, 4′) arranged at at least one of the first and second surfaces (101a, 101b) of the substrate (101); an isolation structure (109) in the substrate (101) defining a Hall sensor plate (103) of the integrated Hall sensor, the Hall sensor terminals being arranged in the isolation structure (109). The integrated Hall sensor moreover has a test or calibration coil integrated in the wafer (10), having a plurality of windings formed, at least in part, by metal portions (130b, 170b; 130a, 170a) arranged above the first and second surfaces (101a, 101b) of the substrate (101) and defining an inner volume (1001) entirely enclosing the Hall sensor plate (103).