Segmented Buried Power Rails for Thermally Stable FEOL Processing

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Solution Overview

Problem

Scaling semiconductor devices poses challenges due to increased resistance and heat generation from power rails, which are exacerbated by their length-to-width ratio and high-temperature processing, leading to thermomechanical stress failures.

Innovation Solution

Divide buried power rails into multiple segments with shorter lengths to reduce thermomechanical stress failures by minimizing material volume changes during high-temperature processing, and connect these segments to a backside power distribution network.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If power rails are scaled to smaller dimensions, then device size is reduced, but resistance increases and heat generation increases

Engineering Contradiction:

Improvepower rail lengthVSAvoidthermomechanical stress failure

Core Design Contradiction:

Length of moving objectVSReliability

Solution Approach 1:

The power rail is divided into multiple segments separated by gaps, where each segment has a length less than the total power rail length. This segmentation reduces the material volume in each segment, minimizing thermomechanical stress during high-temperature processing while maintaining electrical connectivity through the gaps.

Inventive Principle:

Principle #1Segmentation

2Power

If power rail length is increased to provide sufficient power distribution, then power delivery improves, but resistance increases and heat generation increases

Engineering Contradiction:

Improvepower delivery capabilityVSAvoidheat generation

Core Design Contradiction:

PowerVSLoss of energy

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a vertical dimension by forming the segmented power rail structure within a three-dimensional semiconductor device architecture. This allows power distribution along the length while managing thermal and mechanical stress through the segmented configuration, effectively distributing power without proportionally increasing heat generation in any single location.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS12598980B2Front end of line processing compatible thermally stable buried power rails

Publication Date: 2026.04.07 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

Semiconductor devices, and methods of their formation, are provided. The semiconductor device can include a substrate; a wiring level within the substrate; and at least one buried power rail within the wiring level, wherein the at least one buried power rail is divided into a plurality of rail segments, wherein each rail segment of the plurality of rail segments has a length smaller than a total length of the buried power rail.