Hermetic Guard Ring Structure for Moisture-Sealed SOI Bonding Layers

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Solution Overview

Problem

The bonding layer in semiconductor on insulator (SOI) devices is prone to weakness due to exposure, leading to moisture absorption and thermal/mechanical integrity loss, causing delamination and performance issues.

Innovation Solution

A hermetic guard ring structure is implemented, comprising a liner, barrier layer, and fill material, which surrounds the semiconductor devices and extends through the bonding, interconnect, and device layers to create a moisture-blocking seal, enhancing bond strength and mechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the device wafer is bonded to the insulator-semiconductor wafer through silicon dioxide bonding, then the ability to grind a large portion of the device wafer is achieved, but the bonding layer becomes weak and exposed to moisture

Engineering Contradiction:

Improvewafer grinding precisionVSAvoidbonding layer integrity

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The device structure is segmented into distinct functional layers: the ground device wafer layer, the bonding layer, and the added insulator-semiconductor wafer layer. This segmentation allows the device wafer to be ground to precise thickness while the bonding layer remains intact, and the insulator-semiconductor wafer provides additional protection and structural integrity to prevent bonding layer failure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs composite material construction by bonding the device wafer to an insulator-semiconductor wafer through a silicon dioxide bonding layer. This composite structure combines the advantages of each material: the ground device wafer provides precise dimensional control, the silicon dioxide bonding layer provides strong adhesion, and the insulator-semiconductor wafer provides mechanical support and moisture protection, collectively preventing bonding layer delamination.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If the bonding layer is exposed to the environment, then manufacturing simplicity is maintained, but moisture absorption causes bond strength to decrease

Engineering Contradiction:

Improvebonding process simplicityVSAvoidbond strength

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The insulator-semiconductor wafer acts as a protective shell or film that encapsulates and protects the bonding layer from environmental moisture. This thin film structure maintains the simplicity of the bonding process while providing a barrier that prevents moisture ingress, thereby preserving bond strength during device operation and temperature cycling.

Inventive Principle:

Principle #30Flexible shells and thin films

3Adaptability or versatility

If the bonding layer is subjected to temperature cycling, then device operational flexibility is improved, but fatigue stresses cause bonding layer opening

Engineering Contradiction:

Improvetemperature cycling toleranceVSAvoidbonding layer continuity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The insulator-semiconductor wafer is added beforehand to provide mechanical support and stress distribution to the bonding layer. This cushioning structure prevents the bonding layer from opening under fatigue stresses during temperature cycling, maintaining bonding layer continuity while allowing the device to operate through temperature variations.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

4Object-generated harmful factors

If the device wafer is ground to thin thickness, then leakage control is improved, but mechanical integrity and bonding strength are reduced

Engineering Contradiction:

Improveleakage currentVSAvoidmechanical integrity

Core Design Contradiction:

Object-generated harmful factorsVSStrength

Solution Approach 1:

The patent creates a composite structure where the thin ground device wafer is bonded to a thicker insulator-semiconductor wafer. This composite construction allows the device wafer to be ground to thin thickness for improved leakage control, while the combined structure maintains adequate mechanical integrity and bonding strength through the supporting insulator-semiconductor wafer layer.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS12014996B2Moisture hermetic guard ring for semiconductor on insulator devices

Publication Date: 2024.06.18 INTEL CORP

AI summary

Moisture hermetic guard ring structures for semiconductor devices, related systems, and methods of fabrication are disclosed. Such devices systems, and methods include a guard ring structure laterally surrounding semiconductor devices of a device layer and metal interconnects of an interconnect layer, the guard ring structure extending through the interconnect layer, the device layer, and a bonding layer adjacent one of the interconnect layer or the device layer the bonding layer, and contacting a support substrate coupled to the bonding layer. Such devices systems, and methods may further include via structures having the same material system as the guard ring structure and also extending through the interconnect, the device, and bonding layers and contacting a support substrate.