Magnetic Sensor Base Layer Curvature for Offset Voltage Reduction
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Solution Overview
Problem
Magnetic sensors used in digital compasses face issues with high offset voltage due to stress on Hall-effect elements, leading to reduced sensitivity and difficulty in detecting minute changes in magnetic fields.
Innovation Solution
A semiconductor-based magnetic sensor design featuring a base layer with a larger cross-sectional area than the integrated magnetic concentrator, incorporating a protruding portion and elevated surfaces to reduce stress on Hall elements, and a manufacturing method that includes forming a semiconductor substrate with Hall elements, a protective layer, and an integrated magnetic concentrator with a bent surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a flat-shaped integrated magnetic concentrator is used to amplify terrestrial magnetism, then magnetic field amplification is achieved, but high stress is applied to Hall elements causing increased offset voltage
Solution Approach 1:
The base layer is designed with a curved surface instead of a flat surface. Specifically, the base layer has a concave portion that corresponds to the integrated magnetic concentrator, creating a curved support structure. This curvature distributes the stress from the magnetic concentrator more evenly across the Hall elements, preventing the high localized stress that causes offset voltage while maintaining magnetic field amplification capability.
Solution Approach 2:
The base layer acts as an intermediary between the integrated magnetic concentrator and the Hall elements. By positioning the Hall elements on the curved surface of the base layer rather than directly on a flat substrate, the base layer mediates the stress transmission, reducing the harmful stress concentration on the Hall elements that would otherwise occur with a flat configuration.
2Measurement precision
If thick magnetic field concentrators are used for magnetic amplification, then magnetic signal strength is improved, but stress on Hall elements increases leading to higher offset voltage
Solution Approach 1:
The curved surface design of the base layer with its concave portion accommodates the thick integrated magnetic concentrator while distributing the resulting stress. The curvature allows the thick concentrator to maintain its magnetic amplification function without concentrating excessive stress on the Hall elements, thereby reducing offset voltage.
Solution Approach 2:
The invention changes the geometric parameter of the base layer surface from flat to curved. This parameter change in the support structure modifies how stress is distributed when thick magnetic concentrators are used, transforming the stress distribution pattern to reduce harmful concentrations on the Hall elements while preserving the magnetic amplification benefit.
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 design effectively reduces offset voltage and enhances the sensitivity of the magnetic sensor by minimizing stress on Hall elements, improving the detection of magnetic fields.
Implementation Method 1
Hall effect occurs in the presence of a magnetic field. With the application of a predetermined voltage to the semiconductor substrate, electrons or holes move, and the direction of the electrons or holes change due to the amplified magnetic field.
Data Source
AI summary
A magnetic sensor (200 and a manufacturing method thereof are provided. The magnetic sensor (200) includes: a substrate (220) comprising a plurality of Hall elements (210), a protective layer (230) formed on the substrate (220), a base layer (240) formed on the protective layer (220), and an integrated magnetic concentrator (IMC, 250) formed on the base layer (240) and comprising a surface with an elevated portion. The base layer (240) has a larger cross-sectional area than the IMC (250).