Magnetic Sensor Trench Cap for Stress Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing magnetic field sensors in semiconductor substrates face challenges with mechanical stress-induced sensitivity drift and cross-dependency on environmental factors like temperature, which complicates compensation and increases power consumption and production costs, and existing trench-based solutions are prone to mechanical stress transfer and encapsulation issues.
Innovation Solution
A magnetic field sensor is partially surrounded by a trench in a semiconductor substrate, covered with a cap to prevent encapsulation material penetration and mechanical stress transfer, with a connecting bridge for signal processing and optional buffer materials to absorb stresses, reducing the need for additional sensors and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a trench is used to isolate the sensor from mechanical stresses, then sensitivity drift is reduced, but the trench is prone to mechanical stress transfer and encapsulation material penetration
Solution Approach 1:
A cap structure is introduced as an intermediary element between the trench and the external environment. The cap covers the trench opening and prevents encapsulation material from penetrating into the trench while also blocking mechanical stress transfer to the sensor. This mediator resolves the contradiction by providing protection without compromising the trench's stress isolation function.
Solution Approach 2:
The protection system is segmented into multiple functional parts: the trench structure for stress isolation, the cap for sealing and stress blocking, and the connecting bridge for electrical connection. This segmentation allows each component to perform its specific function optimally - the trench isolates mechanical stresses, the cap prevents material penetration and stress transfer, and the bridge maintains electrical connectivity.
2Measurement precision
If additional stress measurement sensors are added to compensate for mechanical stress, then sensitivity drift can be corrected, but chip area and power consumption increase
Solution Approach 1:
The invention converts the harmful mechanical stresses that cause sensitivity drift into a beneficial design feature by using the trench and cap structure to prevent stress formation in the first place. This preventive approach eliminates the need for additional stress measurement sensors and compensation circuitry, saving chip area and power while still achieving accurate magnetic field measurements.
Solution Approach 2:
The harmful mechanical stress factors are extracted or removed from the sensor environment through the trench and cap structure. By physically isolating the sensor from stress-inducing elements in the substrate and packaging, the need for additional measurement and compensation components is eliminated, reducing overall device complexity.
3Reliability
If the trench is filled with encapsulation material during packaging, then the component is sealed, but mechanical stresses are transferred from one side to the other
Solution Approach 1:
The cap acts as an intermediary barrier that prevents encapsulation material from filling the trench while still allowing the component to be sealed. The cap covers the trench opening, blocking both material penetration and mechanical stress transfer, thus resolving the contradiction between sealing and stress isolation.
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 effectively isolates the sensor from mechanical stresses, reduces sensitivity drift, and eliminates the need for additional stress measurement components, saving chip area and power while enhancing reliability by preventing encapsulation-related failures.
Implementation Method 1
a magnetic field sensor (30), the magnetic field sensor (30) being partially surrounded by a trench (40) in a semiconductor substrate (20)
Implementation Method 2
the magnetic field sensor (30) and the trench (40) being covered with a cap (80)
Implementation Method 3
A connection between a signal processing processor and the magnetic field sensor is provided on a connecting bridge
Implementation Method 4
an additional layer of a buffer material can be applied to the semiconductor substrate in order to absorb mechanical stresses which act between the Si or sensor surface (island) and the potting compound
Data Source
Figure 1a~1d
Figure 2~2p
Figure 3
AI summary
A component (10) with a magnetic field sensor (30) is described. The electronic component (30) is located in a semiconductor substrate (20) or on the surface (25) of the semiconductor substrate (20) and is at least partially, preferably largely, surrounded by a groove (40) in the semiconductor substrate (20). The groove (40) and the magnetic field sensor (30) are/are covered with a cap (80).