Through Silicon Via Guard Ring for Diffusion Barrier

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Solution Overview

Problem

Current semiconductor chips face issues with moisture and metal diffusion through silicon vias, particularly in low-k dielectric materials used in back end of the line (BEOL) wiring, which can degrade the insulating properties and lead to incomplete metallization coverage and subsequent diffusion into wiring layers.

Innovation Solution

Incorporating a guard ring made of metallic or nonmetallic material surrounding the through silicon via, which acts as a barrier to prevent moisture and metal diffusion, ensuring complete coverage and preventing metallization from entering functional wiring layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If through silicon via is formed to connect chips, then chip stacking and interconnection are enabled, but moisture and metal diffusion through the via degrades insulating properties

Engineering Contradiction:

Improvechip interconnection reliabilityVSAvoidmoisture and metal diffusion

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A guard ring structure is introduced as an intermediary element between the through silicon via and the surrounding BEOL wiring. This guard ring acts as a barrier that intercepts and prevents moisture and metal diffusion pathways, thereby protecting the insulating material without interfering with the electrical function of the via

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The protection mechanism is segmented into distinct functional zones: the through silicon via for electrical connection, the guard ring for diffusion barrier, and the insulating material for electrical isolation. This segmentation allows each component to perform its specific function optimally without compromising others

Inventive Principle:

Principle #1Segmentation

2Reliability

If low-k dielectric material is used in BEOL wiring, then insulating properties are improved, but moisture diffusion through silicon via degrades the insulating properties

Engineering Contradiction:

Improveinsulating propertiesVSAvoidinsulating material integrity

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The guard ring serves as a protective intermediary that shields the low-k dielectric material from moisture and metal diffusion originating at the through silicon via, thereby maintaining the material's insulating properties and compositional stability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The guard ring is formed prior to final via metallization and wiring completion, providing pre-established protection against moisture and metal diffusion that could otherwise compromise the low-k dielectric material during subsequent processing and operation

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If metallization is deposited in through silicon via, then conductive path is formed, but incomplete coverage leads to metal diffusion into wiring layers

Engineering Contradiction:

Improveconductive path formationVSAvoidmetal diffusion into wiring layers

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The guard ring acts as a physical intermediary barrier that contains any metallization material within the via region. Even if metallization coverage is incomplete or excess material is deposited, the guard ring prevents metal from diffusing into the surrounding BEOL wiring layers

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The guard ring structure is established before final metallization deposition, creating a pre-configured containment structure that guides and limits metallization to the intended via region, preventing unwanted metal diffusion into adjacent wiring

Inventive Principle:

Principle #10Preliminary action

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 guard ring effectively blocks moisture and metal diffusion, maintaining the integrity of the insulating material and preventing metallization from entering the BEOL wiring layers, thus enhancing the reliability and performance of semiconductor chips.

Implementation Method 1

a guard ring surrounding the through silicon via in the BEOL wiring portion

Methodology Applied

Scientific EffectDiffusion barrier: Diffusion Barrier

Implementation Method 2

a through silicon via providing a conductive path through the BEOL wiring portion and the semiconductor base portion

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS8232648B2Semiconductor article having a through silicon via and guard ring

Publication Date: 2012.07.31 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

Disclosed is a semiconductor article which includes a semiconductor base portion, a back end of the line (BEOL) wiring portion on the semiconductor base portion, a through silicon via and a guard ring. The semiconductor base portion is made of a semiconductor material. The BEOL wiring portion includes a plurality of wiring layers having metallic wiring and insulating material. The BEOL wiring portion does not include a semiconductor material. The through silicon via provides a conductive path through the BEOL wiring portion and the semiconductor base portion. The guard ring surrounds the through silicon via in the BEOL wiring portion.