MEMS Package Resin Stress Decoupling Structure

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Solution Overview

Problem

MEMS sensors face measurement errors due to thermal expansion and external stresses caused by varying temperatures and materials with different coefficients of thermal expansion in their packages, leading to countervailing stresses on movable components.

Innovation Solution

A MEMS sensor package design featuring a laminate base layer with a through-hole opening, a resin layer adhered to the internal edge surfaces of the through-hole, and a MEMS support layer surrounded by the resin layer, which absorbs and decouples stresses, preventing them from being transmitted to the MEMS sensor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a laminate base layer with through-hole is used to support MEMS sensor, then structural support and electrical connection are provided, but thermal expansion differences cause countervailing stresses on movable components

Engineering Contradiction:

Improvestructural supportVSAvoidmeasurement accuracy

Core Design Contradiction:

StrengthVSMeasurement precision

Solution Approach 1:

A stress absorption layer is introduced as an intermediary between the laminate base layer and the MEMS sensor package. This layer acts as a mediator that absorbs and dissipates thermal expansion stresses, preventing them from being transmitted to the movable components of the MEMS sensor, thereby maintaining measurement accuracy while preserving structural support functionality

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The coefficient of thermal expansion of the stress absorption layer is specifically selected to be between that of the laminate base layer and the MEMS sensor package. This parameter optimization allows the stress absorption layer to gradually transition and absorb thermal stresses, reducing the countervailing stresses on movable components while maintaining structural integrity

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If materials with different coefficients of thermal expansion are used in the package, then diverse functional requirements are met, but thermal stresses cause measurement errors

Engineering Contradiction:

Improvematerial selection flexibilityVSAvoidmeasurement accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The stress absorption layer uses a material with a specifically engineered coefficient of thermal expansion that is intermediate between the laminate base layer and the MEMS sensor package. This parameter optimization allows the system to accommodate materials with different thermal expansion properties while minimizing thermal stress-induced measurement errors

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The package employs a composite structure combining the laminate base layer, stress absorption layer, and MEMS sensor package. This composite design allows each layer to have different material properties optimized for its specific function, enabling material selection flexibility while maintaining measurement accuracy through the stress-absorbing composite structure

Inventive Principle:

Principle #40Composite materials

3Measurement precision

If a stress absorption layer is added to reduce thermal stresses, then measurement accuracy is improved, but device complexity increases

Engineering Contradiction:

Improvemeasurement accuracyVSAvoidpackage structure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The stress absorption layer is implemented as a thin film or shell structure that can be integrated into the existing package architecture. This thin-film approach provides effective stress absorption while minimizing the increase in device complexity and maintaining a compact package structure

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The stress absorption layer is designed to perform multiple functions: absorbing thermal expansion stresses, providing structural support, and maintaining mechanical alignment. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving improved measurement accuracy

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 measurement errors by dissipating physical and thermal stresses within the resin layer, maintaining the MEMS sensor's accuracy across diverse environmental conditions.

Implementation Method 1

a resin layer adhered to and covering the internal edge surfaces of the through hole... effectively reduces measurement errors by dissipating physical and thermal stresses within the resin layer

Methodology Applied

Scientific EffectViscoelasticity: Viscoelasticity

Data Source

PatentUS11760627B2MEMS stress reduction structure embedded into package

Publication Date: 2023.09.19 INVENSENSE INC

AI summary

A microelectromechanical system (MEMS) sensor package includes a laminate that provides physical support and electrical connection to a MEMS sensor. A resin layer is embedded within an opening of the laminate and a MEMS support layer is embedded within the opening by the resin layer. A MEMS structure of the MEMS sensor is located on the upper surface of the MEMS support layer.