Through-Via Guard Ring Layout for Stress Relief and PID Protection

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Solution Overview

Problem

BEOL-only TSVs and guard ring structures cause stress on surrounding structures, leading to delamination, cracks, and poor plasma-induced damage (PID) protection due to their separation from FEOL and MEOL processes.

Innovation Solution

Integrate BEOL and FEOL features in the guard ring structure, with the guard ring landing on FEOL features and being biased to ground for improved PID protection, and optionally connecting to TSVs to spread stress and reduce stray capacitance, while incorporating corner stress relief regions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If BEOL-only TSVs and guard ring structures are used, then manufacturing simplicity is maintained, but stress on surrounding structures increases causing delamination and cracks

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidstructural integrity

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent merges the guard ring structure with FEOL features (fin-like active regions) by having the guard ring land on and electrically connect to these features. This integration allows the guard ring to serve dual purposes: providing PID protection through electrical connection to ground while simultaneously mechanically supporting the TSV to reduce stress and prevent delamination or cracking.

Inventive Principle:

Principle #5Merging (Combining)

2Device complexity

If BEOL-only guard ring structures are used, then process simplicity is maintained, but plasma-induced damage protection is poor

Engineering Contradiction:

Improveprocess complexityVSAvoidplasma-induced damage

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The guard ring is merged with FEOL features during the FEOL process itself, rather than being added separately in the BEOL. By landing the guard ring on fin-like active regions that are already formed, the structure gains electrical connection to ground through these FEOL features, providing effective PID protection without adding significant process complexity.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If guard ring connects to TSV, then stress spreading improves, but stray capacitance increases

Engineering Contradiction:

Improvestress distributionVSAvoidstray capacitance

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The guard ring acts as an intermediary structure that connects to both the TSV and FEOL features (fin-like active regions). This intermediary connection allows stress to spread from the TSV into the broader FEOL structure, improving mechanical reliability. The electrical connection to ground through the FEOL features also provides a discharge path that can reduce stray capacitance effects.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS20250357375A1Through via with guard ring structure

Publication Date: 2025.11.20 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A semiconductor device and methods for forming the same are provided. The semiconductor device includes first active regions in a first region of the semiconductor device, second active regions in a second region of the semiconductor device, the second region encircling the first region, epitaxial features disposed on the second active regions, an interconnect structure disposed over the first and second regions, the interconnect structure comprising metal lines disposed in dielectric layers, and a through via disposed in the first region and extending through the first active regions. A portion of the metal lines in the interconnect structure form a guard ring encircling the through via, and the guard ring is electrically coupled to the epitaxial features.