Shield Plate for IC Package Stress Mitigation

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Solution Overview

Problem

Integrated circuit packages face performance deterioration due to stress-induced modifications in sensitive electronic circuits caused by molding materials, which can lead to unacceptable shifts in output voltage, particularly in precision components like bandgap reference circuits.

Innovation Solution

Incorporating a shield plate adhered to the integrated circuit die over sensitive portions, which absorbs and distributes stresses from the molding material, thereby shielding the sensitive circuits from mechanical, thermal, and moisture-induced stresses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If molding material is applied over the integrated circuit die for protection and encapsulation, then the die is protected from environmental factors, but stress is induced on stress-sensitive circuits causing performance deterioration

Engineering Contradiction:

Improveprotection of integrated circuit dieVSAvoidstress-induced performance deterioration

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A shield plate is introduced as an intermediary component between the molding material and the integrated circuit die. The shield plate absorbs and distributes the stress induced by the molding material, preventing direct transmission of stress to stress-sensitive circuits while maintaining the protective encapsulation function.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The shield plate is strategically positioned to cover only specific stress-sensitive regions of the integrated circuit die, rather than the entire die surface. This selective coverage segments the protection function to where it is most needed, reducing stress on sensitive circuits while leaving other areas exposed.

Inventive Principle:

Principle #1Segmentation

2Reliability

If a shield plate is added to protect stress-sensitive circuits from molding material stress, then circuit performance is maintained, but device complexity increases

Engineering Contradiction:

Improveperformance of stress-sensitive circuitsVSAvoidpackage structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The shield plate covers only the specific regions containing stress-sensitive circuits rather than the entire die surface. This localized approach provides protection where needed while minimizing the addition of structural complexity and material usage.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The shield plate is implemented as a simple, thin layer of material that can be easily applied and integrated into the packaging process. The low cost and simplicity of this component allow it to be added without significantly increasing overall device complexity or manufacturing cost.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 shield plate effectively maintains the performance of sensitive circuitry by absorbing and distributing stresses, reducing voltage shifts and ensuring consistent operation across varying environmental conditions without the need for recalibration.

Implementation Method 1

A shield plate can be attached by an adhesive to the top surface of the integrated circuit die

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS9786609B2Stress shield for integrated circuit package

Publication Date: 2017.10.10 ANALOG DEVICES INT UNLTD CO

AI summary

A stress shield for a plastic integrated circuit package is disclosed. A shield plate is attached by an adhesive to a top surface of an integrated circuit die such that the shield plate covers less than all of the top surface and leaves bond pads exposed. A molding material is applied over the shield plate and the integrated circuit die. The shield plate shields the integrated circuit die from stresses imparted by the molding material.