Wafer-Level Hydrogen Getter for Semiconductor Reliability

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Solution Overview

Problem

Hydrogen degradation of semiconductor materials in wafer-level packages, particularly in high electron mobility transistors, due to hydrogen penetration through thin nitride passivation layers, leading to device failure over time.

Innovation Solution

Integration of hydrogen getters, comprising titanium, nickel, and palladium layers within the wafer-level package, deposited during integrated circuit fabrication, to absorb and remove hydrogen from the hermetically sealed cavity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thin nitride passivation layers are used in HEMT devices, then device performance is improved, but hydrogen penetration increases causing degradation

Engineering Contradiction:

Improvedevice performanceVSAvoidhydrogen penetration

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A hydrogen getter layer is introduced as an intermediary component between the external environment and the HEMT device. This getter layer absorbs hydrogen atoms before they can penetrate through the thin nitride passivation layer and reach the metal interconnects, thereby protecting the device while maintaining the performance benefits of thin passivation layers.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention converts the harmful presence of hydrogen (which naturally penetrates through thin passivation layers) into a beneficial protective mechanism by using hydrogen-absorbing getter materials. The getter layer is designed to preferentially absorb hydrogen, transforming the degradation mechanism into a protective function that extends device lifetime.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Reliability

If hydrogen getters are added to the wafer-level package, then hydrogen degradation is prevented, but device complexity increases

Engineering Contradiction:

Improveprotection from hydrogen degradationVSAvoidpackage structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The hydrogen getter layer is merged with existing package structures such as the bonding ring or cover wafer. By integrating the getter function into components that already form part of the hermetic seal, the design adds protective functionality without creating separate discrete components, thereby minimizing increases in device complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The bonding ring or cover wafer is designed to serve multiple functions: providing hermetic sealing, mechanical support, and hydrogen absorption. This multi-functionality reduces the need for additional dedicated hydrogen getter components, simplifying the overall package structure while maintaining protection against hydrogen degradation.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Quantity of substance

If multiple metal layers are deposited for hydrogen gettering, then hydrogen absorption capacity increases, but manufacturing complexity increases

Engineering Contradiction:

Improvehydrogen absorption capacityVSAvoidfabrication process

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The hydrogen getter is segmented into multiple thin metal layers (such as titanium, nickel, and palladium) deposited in sequence. Each layer contributes to hydrogen absorption capacity while the segmented structure allows for controlled deposition processes and better integration with existing semiconductor fabrication techniques, managing manufacturing complexity through systematic layering.

Inventive Principle:

Principle #1Segmentation

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

Effectively prevents hydrogen degradation of integrated circuit components by absorbing hydrogen within the package, thereby enhancing the longevity and reliability of semiconductor devices.

Implementation Method 1

hydrogen getters within the wafer-level package that absorb the hydrogen to remove it from the sealed cavity

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

deposit certain layers of material within the wafer-level package that operate to absorb hydrogen

Methodology Applied

Scientific EffectAdsorption: Adsorption

Data Source

PatentUS7777318B2Wafer level packaging integrated hydrogen getter

Publication Date: 2010.08.17 NORTHROP GRUMMAN SYSTEMS CORP

AI summary

A wafer-level package that employs one or more integrated hydrogen getters within the wafer-level package on a substrate wafer or a cover wafer. The hydrogen getters are provided between and among the integrated circuits on the substrate wafer or the cover wafer, and are deposited during the integrated circuit fabrication process. In one non-limiting embodiment, the substrate wafer is a group III-V semiconductor material, and the hydrogen getter includes a titanium layer, a nickel layer, and a palladium layer.