MEMS Package Vibration Damping via Solder Bump Integration

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Solution Overview

Problem

MEMS device packages on printed circuit boards experience unwanted vibrations due to resonance, which can lead to errors in motion or posture detection, and existing solutions like conformal coating and underfilling increase production costs and complexity.

Innovation Solution

A method involving the application of a solder pad under the MEMS component package on a printed circuit board, which transforms into a solder bump during the reflow process, providing a non-galvanic contact to the non-conductive package body, thus damping vibrations without additional manufacturing steps or redesign.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conformal coating or underfilling is applied to reduce vibration, then vibration damping is improved, but manufacturing cost and process complexity increase

Engineering Contradiction:
Improvevibration dampingVSAvoidmanufacturing process complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent combines the vibration damping function with the existing soldering process by applying solder paste to create solder pads that are integrated into the reflow soldering step. This merges two functions (damping and joining) into a single process, eliminating the need for separate conformal coating or underfilling steps, thereby reducing manufacturing complexity while maintaining vibration damping effectiveness.

Inventive Principle:
Principle #5Merging (Combining)

2Object-affected harmful factors

If conformal coating or underfilling is applied to reduce vibration, then vibration damping is improved, but manufacturing cost increases

Engineering Contradiction:
Improvevibration dampingVSAvoidmanufacturing cost
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The solder paste serves dual purposes: it provides the necessary vibration damping and simultaneously performs the electrical connection function during the reflow soldering process. This self-service approach eliminates the need for additional materials like conformal coating or underfilling, thereby reducing material costs and simplifying the manufacturing process.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If the component package is designed for high q-factor, then measurement precision is improved, but resonance gain increases causing more vibration sensitivity

Engineering Contradiction:
Improvedetection accuracyVSAvoidresonance sensitivity
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies solder pads beneath the component package body before the component is subjected to harsh environments or vibration. These pre-applied solder pads create damping structures that counteract the resonance effects, allowing the component to maintain its high q-factor for accurate detection while being protected from vibration-induced errors through the preliminary damping configuration.

Inventive Principle:
Principle #9Preliminary anti-action

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 approach effectively reduces vibration damping without increasing manufacturing costs or complexity, shifting resonance frequencies away from critical operational ranges, resulting in more accurate MEMS device readings.

Implementation Method 1

Soldering is a well-known process in which two or more items are joined together by melting a filler metal called solder into the joint

Methodology Applied
Scientific EffectSoldering: Soldering

Implementation Method 2

the entire assembly is subjected to controlled heat, which melts the solder paste and permanently connects the joint(s)

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 3

The solder bump attaches with a non-galvanic contact directly to the flat, electrically non-conductive plastic bottom of the body

Methodology Applied
Scientific EffectMechanical attachment: Mechanical Fastener

Data Source

PatentEP3470366B1Reducing vibration of a MEMS installation on a printed circuit board
Publication Date: 2020.07.08 MURATA MFG CO LTD
  • EP3470366B1 patent drawingFigure 1a~1d
  • EP3470366B1 patent drawingFigure 1e~1f
  • EP3470366B1 patent drawingFigure 2a~2b

AI summary

The present invention relates to a method for installing a MEMS component package on a PCB and to an installation comprising a PCB with a MEMS component package installed on it achieved with the method. the MEMS component package comprises a body having outer surfaces of electrically non-conductive material and a plurality of electrically conducting leads protruding from the body. At least one solder pad is applied on at least one blind pad exposed on a PCB surface simultaneously with applying solder paste for electrically joining the leads to the PCB to pin pads. The at least one blind pad disposed at a location collocated with an intended location of the body, and the at least one solder pad is collocated with the at least one blind pad. The MEMS component package is placed on the PCB surface, joining the leads temporarily to the pin pads of the printed circuit board with solder paste. In a reflow process, the PCB is subjected to controlled heat configured melt the solder paste. This electrically couples the leads to the pin pads, and simultaneously melts the at least one solder pad. The melting is configured to transform the at least one solder pad into a solder bump configured to couple the body to the at least one blind pad. The solder bump attaches with a non-galvanic contact directly to the electrically non-conductive plastic bottom of the body.