Bottom-Up Metal Liner Gap Fill for Seam-Free Semiconductor Features

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Solution Overview

Problem

Conventional deposition processes face challenges in achieving defect-free filling of small features in semiconductor manufacturing due to overhang and low sidewall coverage, particularly in devices with critical dimensions below 20 nm, and lack selective metal deposition methods on metal or metal silicide without damaging the underlying material.

Innovation Solution

A method involving physical vapor deposition (PVD) of a first metal liner, followed by the formation of a flowable polymer film within features, selective removal of the metal liner from the top and sidewalls, and subsequent PVD deposition of a second metal liner, allowing for selective metal layer filling without damaging the underlying metal or metal silicide, enabling bottom-up gap fill without seams or voids.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If PVD processes are used to deposit metal liner, then the metal liner can be deposited conformally, but overhang and low sidewall coverage occur preventing effective gap fill

Engineering Contradiction:

Improvegap fill qualityVSAvoidsidewall coverage

Core Design Contradiction:

Manufacturing precisionVSShape

Solution Approach 1:

A flowable polymer is deposited onto the metal liner before the metal liner is removed, protecting the bottom portion of the feature where the metal liner will remain after selective removal. This preliminary protection enables subsequent selective metal deposition without damaging the underlying metal or metal silicide.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The metal liner deposition process is divided into multiple stages: first depositing a metal liner, then selectively removing portions from the top and sidewalls while preserving the bottom portion through polymer protection, and finally depositing additional metal selectively on the remaining liner. This segmentation enables precise control over where metal remains and where it is removed.

Inventive Principle:

Principle #1Segmentation

2Manufacturing precision

If selective metal deposition is attempted on metal or metal silicide, then the metal can be selectively deposited, but the underlying metal or metal silicide is damaged

Engineering Contradiction:

Improveselective metal depositionVSAvoiddamage to underlying metal

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

A flowable polymer is used as an intermediary protective layer between the metal liner and the selective metal deposition process. The polymer is deposited onto the metal liner, and during subsequent metal deposition, it protects the underlying metal or metal silicide from damage while allowing selective metal deposition on the exposed metal liner surfaces.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If conventional gap fill processes are used, then features can be filled, but voids and seams remain due to overhang and low sidewall coverage

Engineering Contradiction:

Improvefilling efficiencyVSAvoiddefect-free filling

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The flowable polymer is deposited in advance to protect the bottom metal liner portion before the selective metal deposition process begins. This preliminary protection ensures that when metal is deposited selectively, it adheres properly to the protected bottom liner without creating voids or seams, achieving defect-free filling.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The flowable polymer acts as an intermediary that enables defect-free filling by protecting the underlying metal liner during selective metal deposition. It prevents direct contact between the deposited metal and the underlying metal or metal silicide, eliminating the formation of voids and seams that occur in conventional processes.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 approach ensures effective filling of features with minimal voids and seams, improving semiconductor device quality by maintaining the integrity of the underlying metal or metal silicide and enhancing process efficiency.

Implementation Method 1

forming a first flowable polymer film on the first metal liner within the at least one feature

Methodology Applied

Scientific EffectDeposition: Deposition (physical)

Implementation Method 2

selectively depositing a metal layer on the first metal liner and the second metal liner to fill the at least one feature

Methodology Applied

Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Data Source

PatentUS20250006552A1Bottom-up gap fill processes for semiconductor substrates

Publication Date: 2025.01.02 APPLIED MATERIALS INC

AI summary

Embodiments of the disclosure relate to methods of selectively depositing a metallic material after forming a flowable polymer film to protect a substrate surface within a feature. A first metal liner is deposited by physical vapor deposition (PVD). The flowable polymer film is formed on the first metal liner on the bottom. A portion of the first metal liner is selectively removed from the top surface and the at least one sidewall. The flowable polymer film is removed. In some embodiments, the cycle of depositing a metal liner, forming a flowable polymer film, removing a portion of the metal liner, and removing the flowable polymer film is repeated at least once. A metal layer is deposited on the plurality of metal liners (e.g., first metal liner and the second metal liner) and the metal layer is free of seams or voids.