Guard Trace in IC Package Void for Signal Integrity

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Solution Overview

Problem

In integrated circuit (IC) packages, adhesion voids required for moisture outgassing negatively impact signal trace impedance and signal quality, especially as IC packages shrink and signal traces increase in number, making it impossible to avoid placing traces adjacent to voids.

Innovation Solution

The design incorporates a guard trace within a void in one layer, with a signal trace extending over the guard trace in an adjacent layer, where the guard trace is wider than the signal trace and separated by dielectric material to minimize impedance disruption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If adhesion voids are created to allow moisture outgassing, then IC package damage is prevented, but signal trace impedance is adversely impacted and signal quality deteriorates

Engineering Contradiction:

ImproveIC package reliabilityVSAvoidsignal quality degradation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A guard trace is introduced as an intermediary element between the adhesion void and the signal trace. The guard trace acts as a shield that mitigates the electromagnetic field distortion caused by the void, thereby protecting the signal trace from impedance variations while the void continues to provide moisture outgassing relief

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The guard trace is strategically positioned only in the region where the signal trace passes over or adjacent to the adhesion void. This localized approach provides targeted protection against impedance disruption only where needed, without affecting other areas of the circuit board

Inventive Principle:

Principle #3Local quality

2Productivity

If IC packages are shrunk and signal traces are increased in number, then device integration is improved, but it becomes impossible to avoid placing traces adjacent to adhesion voids

Engineering Contradiction:

Improvedevice integration densityVSAvoidsignal trace impedance disruption

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The guard trace serves as a protective intermediary that enables signal traces to be placed adjacent to adhesion voids without suffering from impedance disruption. This allows higher trace density and better device integration while maintaining signal quality

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The solution moves from a two-dimensional planar layout consideration to a three-dimensional layered approach, where the guard trace is placed in one layer and the signal trace in another layer, allowing them to coexist without direct interference

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS11264338B2Integrated circuit package with through void guard trace

Publication Date: 2022.03.01 INTEL CORP

AI summary

Apparatuses, systems and methods associated with over void signal trace design are disclosed herein. In embodiments, an integrated circuit (IC) package may include a first layer that has a void and a guard trace, wherein a first portion of the void is located on a first side of the guard trace and a second portion of the void is located on a second side of the guard trace. The IC package may further include a second layer located adjacent to the first layer, wherein the second layer has a signal trace that extends along the guard trace. Other embodiments may be described and/or claimed.