Selective Sidewall Conversion for Void-Free Conductive Structures

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Solution Overview

Problem

As semiconductor devices continue to reduce minimum feature sizes for increased integration density, the formation of voids in conductive structures during fabrication leads to increased resistance and performance degradation, necessitating improved methods for forming conductive connections without voids.

Innovation Solution

The formation of conductive structures in cavities is facilitated by removing layers from the sidewalls using a directional treatment process that converts a first material to a second material with a different etch rate, allowing selective removal without damaging underlying structures, followed by deposition of a conductive material to fill the cavity and reduce the aspect ratio.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional fabrication methods are used to form conductive structures in high-aspect-ratio cavities, then the manufacturing process is simpler, but voids form in the conductive material leading to increased resistance and performance degradation

Engineering Contradiction:

Improvevoid formation in conductive structuresVSAvoidfabrication process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

A liner layer is deposited on the cavity sidewalls before filling the cavity with conductive material. This preliminary action modifies the cavity geometry and provides a foundation that guides the conductive material deposition, ensuring complete filling without voids even in high-aspect-ratio cavities.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The liner layer acts as an intermediary between the cavity sidewalls and the conductive material. It facilitates the deposition process by providing a surface that promotes uniform conductive material growth and prevents void formation at the interface between the conductive material and cavity walls.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If the cavity aspect ratio is reduced to prevent void formation, then void-free conductive structures are achieved, but the manufacturing flexibility and device design options are limited

Engineering Contradiction:

Improvevoid-free conductive structuresVSAvoiddevice design flexibility

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The liner layer is selectively deposited only on the cavity sidewalls, creating a localized modification that improves conductive material filling in high-aspect-ratio regions without affecting other parts of the device structure. This allows maintainance of high aspect ratios while achieving void-free conductive structures.

Inventive Principle:

Principle #3Local quality

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

This method reduces the formation of voids, thereby lowering resistance and enhancing the performance of conductive structures in semiconductor devices.

Implementation Method 1

performing a directional treatment process on a targeted portion of the treatable layer to convert the targeted portion to a material different from a non-targeted portion of the treatable layer, wherein the directional treatment process is selected from the group consisting of nitridation, oxidation, chlorination, carbonization

Methodology Applied

Scientific EffectNitridation: Nitriding

Implementation Method 2

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 3

forming a treatable layer over a structure by depositing a layer comprising a metal over a structure

Methodology Applied

Scientific EffectPhysical Vapour Deposition: Physical Vapour Deposition

Data Source

PatentUS12538776B2Methods for selectively removing material

Publication Date: 2026.01.27 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

Provided is a conductive structure and a method for forming such a structure. The method includes forming a treatable layer by depositing a layer comprising a metal over a structure; performing a directional treatment process on a targeted portion of the treatable layer to convert the targeted portion to a material different from a non-targeted portion of the treatable layer, wherein the directional treatment process is selected from the group consisting of nitridation, oxidation, chlorination, carbonization; and selectively removing the non-targeted portion from the structure, wherein the targeted portion remains over the structure.