LCP Lid Pillar Mating for Low-Profile Hermetic Sealing

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Solution Overview

Problem

Current electronic package technologies face challenges in achieving a balance between miniaturization, environmental robustness, and ease of integration, particularly due to the thickness and sealing methods of component lids, which can be inconvenient and not fully hermetic.

Innovation Solution

A low-profile electronic package design featuring a liquid crystal polymer (LCP) lid with pillars that mate with a PWB, allowing for a near-hermetic seal and easy integration, using a conventional solder reflow process for assembly, which also facilitates mechanical robustness and potential removal for further testing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If injection molding is used to create component lids, then environmental robustness is improved, but lid thickness increases and sealing convenience deteriorates

Engineering Contradiction:

Improveenvironmental robustnessVSAvoidlid thickness

Core Design Contradiction:

ReliabilityVSLength of stationary object

Solution Approach 1:

The patent changes the material parameter from conventional molding materials to liquid crystal polymer (LCP), which has inherently lower moisture permeability and allows for thinner while still providing near-hermetic sealing performance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses LCP material that combines the benefits of low moisture permeability with thin profile capability, creating a composite solution that achieves both environmental robustness and reduced thickness

Inventive Principle:

Principle #40Composite materials

2Length of stationary object

If LCP material is used for component lids, then lid profile is reduced and sealing performance is improved, but integration complexity increases

Engineering Contradiction:

Improvelid profileVSAvoidintegration complexity

Core Design Contradiction:

Length of stationary objectVSDevice complexity

Solution Approach 1:

The patent segments the lid structure into modular components with standardized mating rings and pillar-receiving openings, allowing the LCP lid to be integrated using conventional solder reflow processes alongside other surface mount components

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent designs the lid with universal features such as standardized pillar-receiving openings and mating rings that can be integrated using existing conventional solder reflow equipment, making the specialized LCP material compatible with standard manufacturing processes

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Productivity

If conventional solder reflow process is used for lid assembly, then fabrication time is reduced and ease of manufacture is improved, but mechanical robustness during reflow may deteriorate

Engineering Contradiction:

Improvefabrication timeVSAvoidmechanical robustness

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The patent incorporates pillars and mating rings into the lid structure before the reflow process, providing pre-established mechanical interlocking features that prevent movement and ensure robustness during the solder reflow operation

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces complex mechanical assembly operations with a conventional solder reflow process, using the thermal field instead of mechanical fastening, while the pillars provide the necessary mechanical stability during this thermal process

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 reduces fabrication time and cost while providing a robust, hermetic seal with controlled air gaps, enabling miniaturization and ease of integration with existing architectures, and allowing for later removal of the lid for additional testing.

Implementation Method 1

LCP materials have very low moisture permeability and can provide a near-hermetic seal

Methodology Applied

Scientific EffectPermeation: Permeation

Implementation Method 2

a plurality of spaced apart pillars may extend downwardly from a lower surface of the LCP layer and be received in corresponding ones of the plurality of spaced apart pillar-receiving openings

Methodology Applied

Scientific EffectMechanical Fastening: Mechanical Fastener

Implementation Method 3

using a conventional solder reflow process for assembly

Methodology Applied

Scientific EffectSoldering: Soldering

Data Source

PatentUS8912641B1Low profile electronic package and associated methods

Publication Date: 2014.12.16 HARRIS CORP

AI summary

An electronic package includes a printed wiring board (PWB) having a die-receiving cavity therein, a semiconductor die in the die-receiving cavity and coupled to the PWB, and a lid mating ring at an upper surface of the PWB surrounding the die-receiving cavity. The lid mating ring has spaced apart pillar-receiving openings therein. A lid is coupled to the lid mating ring and covers the semiconductor die within the die-receiving cavity. The lid includes a liquid crystal polymer (LCP) layer, and spaced apart pillars extending downwardly from a lower surface of the LCP layer and received in corresponding ones of the spaced apart pillar-receiving openings.