Vertical Hall Sensor Excitation Wiring Positioning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Vertical Hall elements in semiconductor devices are prone to manufacturing variations, leading to sensitivity and offset voltage characteristic fluctuations, and existing calibration methods either reduce calibration magnetic field intensity or increase heat-related issues, affecting accuracy and increasing costs.
Innovation Solution
The semiconductor device is designed with an excitation wiring positioned to overlap the center of the magnetosensitive portion's width, with a specific positional relation that ensures a uniformity value of 0.6 or more, enhancing calibration magnetic field generation efficiency while minimizing intensity variation and heat-induced fluctuations in peripheral circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the excitation wiring is laterally offset from the magnetosensitive portion to reduce variation in calibration magnetic field intensity, then the variation in calibration magnetic field intensity is reduced, but the intensity of the calibration magnetic field applied to the magnetosensitive portion becomes low
Solution Approach 1:
The patent transitions from lateral offset (horizontal dimension) to vertical offset (depth dimension) for positioning the excitation wiring. By placing the excitation wiring below the magnetosensitive portion in the depth direction while maintaining vertical alignment in the lateral direction, the patent achieves both high calibration magnetic field intensity and reduced intensity variation.
Solution Approach 2:
The patent creates an asymmetric spatial relationship between the excitation wiring and magnetosensitive portion by offsetting them in the depth direction rather than laterally. This asymmetric positioning in the vertical dimension allows the excitation wiring to be closely positioned to generate high magnetic field intensity while the vertical alignment maintains uniformity across the magnetosensitive portion width.
2Measurement precision
If the amount of current flowing through the excitation wiring is increased to increase the intensity of the calibration magnetic field, then the intensity of the calibration magnetic field is increased, but the amount of heat generated by the excitation wiring becomes larger
Solution Approach 1:
The patent extracts the harmful thermal effect from the calibration process by using a separate compensation wiring that does not carry calibration current. The excitation wiring is positioned to generate the calibration magnetic field efficiently, while the compensation wiring, located adjacent to peripheral circuits, captures and isolates thermal effects for separate compensation, preventing heat from degrading calibration accuracy.
Solution Approach 2:
The patent introduces a compensation wiring as an intermediary element that mediates between the heat generation from the excitation wiring and the peripheral circuits. This compensation wiring acts as a thermal buffer and measurement reference, allowing the system to account for thermal effects without letting them directly impact the calibration accuracy of the magnetosensitive portion.
3Area of stationary object
If the center position of the excitation wiring is laterally offset from the center position of the magnetosensitive portion by a large amount, then peripheral circuits are close to the excitation wiring, but the characteristics of each peripheral circuit fluctuate due to asymmetric temperature distribution
Solution Approach 1:
The patent resolves the spatial conflict by moving the excitation wiring to the depth dimension (below the magnetosensitive portion) rather than lateral offset. This vertical positioning allows the excitation wiring to occupy minimal lateral area while maintaining effective magnetic field generation, and simultaneously prevents asymmetric thermal impact on peripheral circuits since the excitation wiring is vertically aligned rather than laterally offset.
Solution Approach 2:
The patent segments the functional responsibilities by separating the excitation wiring (for magnetic field generation) from the compensation wiring (for thermal effect measurement). This segmentation allows the excitation wiring to be positioned optimally for magnetic field generation without concern for thermal impact on peripheral circuits, as the compensation wiring independently handles thermal compensation.
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 configuration improves the accuracy of sensor sensitivity estimation by maintaining high magnetic field generation efficiency and reducing thermal effects on peripheral circuits, thus enhancing the overall performance and cost-effectiveness of the semiconductor device.
Implementation Method 1
an excitation wiring 4 having a first end surface and a second end surface in the second direction, and extending in the third direction. The excitation wiring 4 is disposed on a surface side of the semiconductor substrate 2
Implementation Method 2
estimate the sensitivity of the magnetosensitive portion (see, for example, U.S. Pat. No. 9,116,192). Specifically, the invention described in U.S. Pat. No. 9,116,192 is directed to the estimation of an actual sensitivity of the magnetosensitive portion by changing the intensity of the calibration magnetic field and measuring a change in Hall voltage generated from the vertical Hall element
Data Source
AI summary
A semiconductor device includes a semiconductor substrate having a surface perpendicular to the first direction; a vertical Hall element formed in the semiconductor substrate, and including a magnetosensitive portion having a depth in the first direction, a width in the second direction, and a length in the third direction; and an excitation wiring extending in the third direction and disposed above the semiconductor substrate and at a position that overlaps the center position of the width of the magnetosensitive portion, and the value u derived from Expression (1) is 0.6 or more:u=tan-1(W+Wc2h)-tan-1(W-Wc2h)2tan-1(Wc2h)(1)where W is the width of the magnetosensitive portion, Wc/2 is a distance from the center position of the width of the magnetosensitive portion to the first end surface closer thereto, and h is a distance from the center position of the depth of the magnetosensitive portion to the excitation wiring.