Magnetic Sensor Layout With Short Wiring and Sloped Die Pads
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Solution Overview
Problem
Existing magnetic sensors face issues with external noise interference and reduced sensitivity due to longer wire lengths connecting the signal processing IC and the magnetoelectric conversion element, as well as poor magnetic sensitivity against temperature characteristics.
Innovation Solution
The magnetic sensor design includes a configuration where the magnetoelectric conversion element is positioned closer to the signal processing IC, reducing wire lengths and minimizing external noise impact. Additionally, the use of stepped or sloped surfaces on the signal processing IC die pad enhances the adhesion of molding resin, preventing delamination and cracks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the signal processing IC is positioned farther from the magnetoelectric conversion element, then there is more space for layout, but the wire length increases causing greater external noise interference and reduced sensitivity
Solution Approach 1:
The patent merges the signal processing IC and magnetoelectric conversion element into a closely integrated configuration, positioning the IC directly adjacent to or overlapping with the conversion element. This merging minimizes the wire length connecting them, thereby reducing external noise interference and maintaining high magnetic sensitivity while still allowing sufficient space for the overall package layout.
2Reliability
If a flat surface is used on the signal processing IC die pad, then the manufacturing is simpler, but the molding resin adhesion is poor causing delamination and cracks
Solution Approach 1:
The patent applies asymmetry by forming a sloped surface on the die pad instead of using a flat surface. The sloped surface creates an angled interface between the die pad and molding resin, increasing the surface area for adhesion and preventing delamination and cracks. This asymmetric geometry enhances reliability while the sloped surface can be formed through standard manufacturing processes like lapping or etching.
3Adaptability or versatility
If the wire length between signal processing IC and magnetoelectric conversion element is long, then the layout flexibility is better, but the external noise impact increases and magnetic sensitivity decreases
Solution Approach 1:
The patent utilizes three-dimensional spatial arrangement by positioning the signal processing IC to overlap partially or fully with the magnetoelectric conversion element in the vertical dimension. This dimensional approach allows the components to be closely coupled in the Z-axis direction while maintaining horizontal layout flexibility, thereby minimizing wire length and reducing external noise impact without sacrificing layout adaptability.
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 effectively reduces the impact of external noise, enhances magnetic sensitivity, and ensures the quality of the magnetic sensor by preventing delamination and cracks, resulting in a small, highly sensitive, and reliable magnetic sensor.
Implementation Method 1
a magnetoelectric conversion element and detects current based on magnetic flux density generated by current
Data Source
AI summary
A die pad, a signal processing IC, an adhesive layer, and at least one magnetoelectric conversion element included in a magnetic sensor are encapsulated by a molding resin. At least a part of the first end surface of the signal processing IC is positioned on a side closer to the at least one magnetoelectric conversion element than a first end surface of the die pad on a side of the at least one magnetoelectric conversion element in a plan view. An isolation portion into which the molding resin enters is provided between the first surface of the die pad on a side of the first end surface, and the first surface of the signal processing IC on a side of the first end surface, and a thickness of the isolation portion is smaller than a thickness of the die pad.