Magnetic Sensor Trench Isolation for Stress Reduction

Solution Overview

Problem

Existing magnetic field sensors in semiconductor substrates face challenges with mechanical stress-induced sensitivity drift, which is difficult to compensate due to complex stress conditions and environmental dependencies, requiring additional sensors and increased power consumption for stress measurement and processing.

Innovation Solution

A trench in the semiconductor substrate is filled with a resilient buffer material to absorb mechanical stresses, eliminating the need for additional stress measurement sensors and reducing power consumption, and an optional cap is applied to prevent filler intrusion during encapsulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If additional stress measurement sensors and processing circuits are added to compensate for mechanical stress-induced sensitivity drift, then the compensation accuracy is improved, but the device complexity and power consumption increase

Engineering Contradiction:

Improvesensitivity drift compensation accuracyVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the magnetic field sensor from the stressed semiconductor substrate by creating a trench around it and filling the trench with stress-absorbing material. This isolates the sensor from the mechanical stress sources in the substrate, eliminating the need for additional stress measurement sensors and processing circuits, thus reducing device complexity while maintaining measurement precision

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the harmful mechanical stress in the semiconductor substrate into a beneficial feature by filling the trench with resilient buffer material that absorbs the stress. The stress-absorbing material transforms the stress problem into a solution, protecting the sensor without requiring complex compensation circuits

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Measurement precision

If additional stress measurement sensors and processing circuits are added to compensate for mechanical stress-induced sensitivity drift, then the compensation accuracy is improved, but the power consumption increases

Engineering Contradiction:

Improvesensitivity drift compensation accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent extracts the magnetic field sensor from the stressed semiconductor substrate by creating a trench around it and filling the trench with stress-absorbing material. This isolates the sensor from the mechanical stress sources in the substrate, eliminating the need for additional stress measurement sensors and processing circuits, thus reducing device complexity while maintaining measurement precision

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the harmful mechanical stress in the semiconductor substrate into a beneficial feature by filling the trench with resilient buffer material that absorbs the stress. The stress-absorbing material transforms the stress problem into a solution, protecting the sensor without requiring complex compensation circuits

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Strength

If the trench is filled with rigid material during encapsulation, then the structural support is improved, but the mechanical stress is transferred to the sensor

Engineering Contradiction:

Improvestructural supportVSAvoidmechanical stress transfer

Core Design Contradiction:

StrengthVSStress or pressure

Solution Approach 1:

The patent applies local quality by using different materials with different mechanical properties in different regions. The trench filler material has resilient, stress-absorbing properties locally around the sensor, while the encapsulation material provides overall structural support. This local differentiation allows the sensor region to be protected from stress while the package maintains structural integrity

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses composite materials strategy by combining the resilient trench filler material with the rigid encapsulation material. The composite structure allows the rigid encapsulation to provide overall structural support while the resilient filler locally absorbs mechanical stress, preventing stress transfer to the sensor

Inventive Principle:

Principle #40Composite materials

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 solution effectively isolates the magnetic field sensor from mechanical stresses, reducing sensitivity drift and eliminating the need for additional stress measurement components, thereby conserving chip space and reducing power consumption.

Implementation Method 1

The trench is filled with a resilient buffer material which absorbs mechanical stresses

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

The functional layers of the Hall sensor 300 are located below a surface 315 of the silicon substrate 310 in corresponding regions 320, 330 of the semiconductor substrate 310

Methodology Applied

Scientific EffectHall effect: Hall Effect

Data Source

PatentUS10103320B2Component with reduced stress forces in the substrate

Publication Date: 2018.10.16 TDK MICRONAS GMBH

AI summary

A component with a magnetic field sensor. The electronic component is located in a semiconductor substrate or on the surface of the semiconductor substrate and is surrounded at least partially, preferably largely, by a trench in the semiconductor substrate. The trench is filled with a filling material.