Semiconductor Contact Layer via Power Rail Segmentation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The shrinking size of semiconductor devices at the 20 nm node makes it difficult to create standard cell library logic devices due to lithographic limitations, leading to complicated patterning and fabrication challenges in the metal layer, particularly with power rail projections into the diffusion region.

Innovation Solution

A semiconductor device design where the power rail is disposed outside the diffusion region, with a contact layer above the substrate and a via connecting it to the transistor, eliminating the need for power rail projections and allowing simpler metal layer utilization for interconnections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If power tabs extend into the diffusion region to connect power rails to transistors, then electrical connections are established, but the metal layer patterning becomes very complicated and fabrication difficulties arise

Engineering Contradiction:

Improveelectrical connectionVSAvoidmetal layer patterning

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention divides the connection function into separate components: power tabs remain in the metal layer outside the diffusion region, while separate contact structures extend into the diffusion region to reach transistor sources/drains. This segmentation eliminates the need for complicated overlapping patterns while maintaining electrical connectivity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention introduces an intermediary contact structure that bridges the gap between the power rail and transistor. This contact layer acts as a mediator, extending from the metal layer into the diffusion region without requiring the power rail itself to penetrate the diffusion region, thus simplifying the metal layer patterning.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If a second metal layer is used on a different plane to avoid resource conflicts, then routing flexibility is maintained, but routing efficiency reduces and device size increases

Engineering Contradiction:

Improverouting flexibilityVSAvoidrouting efficiency

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The invention resolves the resource conflict by utilizing vertical separation through the contact layer structure rather than adding another metal layer. The contact layer extends into the diffusion region vertically, allowing power connections without occupying horizontal routing space that would be needed for a second metal layer.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS8598633B2Semiconductor device having contact layer providing electrical connections

Publication Date: 2013.12.03 GLOBALFOUNDRIES US INC

AI summary

A semiconductor device includes a semiconductor substrate having a diffusion region. A transistor is formed within the diffusion region. A power rail is disposed outside the diffusion region. A contact layer is disposed above the substrate and below the power rail. A via is disposed between the contact layer and the power rail to electrically connect the contact layer to the power rail. The contact layer includes a first length disposed outside the diffusion region and a second length extending from the first length into the diffusion region and electrically connected to the transistor.