Bottom-Up Tungsten Gapfill for Narrow Semiconductor Features

Solution Overview

Problem

Conventional deposition methods struggle to effectively fill narrow features in semiconductor manufacturing, leading to excessive material deposition on substrate surfaces and the need for additional etching steps, which reduces throughput and increases costs.

Innovation Solution

A method involving physical vapor deposition of tungsten followed by exposure to a metal halide and reductant, such as MoCl5 and H2, to form a metal gapfill within substrate features in a bottom-up, non-conformal fashion, minimizing deposition on the top surface and reducing the need for subsequent etching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional chemical vapor deposition methods are used to fill substrate features, then the feature can be filled with metal material, but excessive material is deposited on the substrate surface outside the feature requiring additional etching steps

Engineering Contradiction:

Improvegapfill qualityVSAvoidmanufacturing throughput

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies local quality by creating non-uniform deposition conditions within the substrate feature. The deposition process is designed to concentrate metal material deposition at the bottom of the feature while minimizing deposition at the top surface, achieving location-specific material distribution that eliminates the need for subsequent etching steps to remove excess material.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent inverts the conventional deposition approach by implementing bottom-up gapfill instead of top-down deposition. Rather than depositing material uniformly from the top surface downward, the process prioritizes filling from the bottom of the feature upward, reversing the traditional deposition sequence to achieve precise gapfill without excess surface deposition.

Inventive Principle:

Principle #13The other way round (Inversion)

2Manufacturing precision

If atomic layer deposition is used to form conformal metal films, then the feature can be filled, but material is deposited on all substrate surfaces requiring etching and seams form in the middle

Engineering Contradiction:

Improvegapfill qualityVSAvoidprocessing steps

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by creating non-uniform deposition conditions within the substrate feature. The deposition process is designed to concentrate metal material deposition at the bottom of the feature while minimizing deposition at the top surface, achieving location-specific material distribution that eliminates the need for subsequent etching steps to remove excess material.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent inverts the conventional deposition approach by implementing bottom-up gapfill instead of top-down deposition. Rather than depositing material uniformly from the top surface downward, the process prioritizes filling from the bottom of the feature upward, reversing the traditional deposition sequence to achieve precise gapfill without excess surface deposition.

Inventive Principle:

Principle #13The other way round (Inversion)

3Manufacturing precision

If conventional deposition methods deposit material on the substrate surface, then the feature can be filled, but additional etching processing is required after gapfill completion

Engineering Contradiction:

Improvegapfill completenessVSAvoidprocessing time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent inverts the conventional deposition approach by implementing bottom-up gapfill instead of top-down deposition. Rather than depositing material uniformly from the top surface downward, the process prioritizes filling from the bottom of the feature upward, reversing the traditional deposition sequence to achieve precise gapfill without excess surface deposition.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent applies taking out by selectively removing the unnecessary step of post-gapfill etching. By designing a deposition process that inherently minimizes surface deposition outside the feature, the method extracts or eliminates the need for additional etching processing steps, streamlining the manufacturing workflow.

Inventive Principle:

Principle #2Taking out (Extraction)

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 allows for efficient filling of substrate features with reduced deposition outside the feature, enhancing manufacturing throughput and minimizing defects by selectively depositing metal gapfill materials primarily at the bottom of the feature.

Implementation Method 1

depositing a second metal material comprising tungsten on a substrate surface with at least one feature formed therein by physical vapor deposition

Methodology Applied

Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Implementation Method 2

exposing the substrate surface to a first metal halide comprising MoCl5 and a reductant comprising H2 to form a first metal gapfill within the at least one feature

Methodology Applied

Scientific EffectChemical vapor deposition: Chemical Vapour Deposition

Data Source

PatentUS20230326744A1Field suppressed metal gapfill

Publication Date: 2023.10.12 APPLIED MATERIALS INC

AI summary

Embodiments of the disclosure relate to methods for bottom-up metal gapfill without substantial deposition outside of the feature. Additional embodiments provide a method of forming a metal material on the top surface of the substrate and the bottom of the feature before depositing the metal gapfill. The disclosed methods