Semiconductor Gap Filling With Bottom-Up Void-Free Deposition

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Solution Overview

Problem

Existing semiconductor manufacturing processes face challenges in effectively filling gaps with materials that avoid voids or seams, particularly in narrow critical dimensions.

Innovation Solution

A method involving alternating deposition and etching back processes to form a filler element within semiconductor structures, ensuring the filler is deposited without lateral growth, using materials like titanium nitride, aluminum oxide, tungsten, ruthenium, or molybdenum, and controlling etching rates to maintain a desired height.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional deposition methods are used to fill narrow gaps, then the gap filling process is simple, but voids or seams form in the filled material

Engineering Contradiction:

Improvegap filling qualityVSAvoidprocess complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The gap filling process is divided into multiple alternating deposition and etching cycles. Each deposition cycle deposits material to a specific height, and each etching cycle removes lateral overgrowth. This segmentation allows precise control over vertical filling while preventing lateral formation, eliminating voids and seams in narrow gaps.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs periodic alternating actions of deposition and etching. The deposition step deposits filling material vertically into the gap, and the subsequent etching step removes lateral overgrowth. This periodic cycle repeats until the gap is completely filled, ensuring high precision without forming defects.

Inventive Principle:

Principle #19Periodic action

2Manufacturing precision

If filling material is deposited to fill the gap completely, then the gap is filled, but lateral formation of the filler element occurs

Engineering Contradiction:

Improvefiller element shape controlVSAvoidmaterial waste

Core Design Contradiction:

Manufacturing precisionVSLoss of substance

Solution Approach 1:

The etching step selectively removes the lateral overgrowth portion of the filling material that formed outside the gap. By extracting only the unwanted lateral material while preserving the vertical fill within the gap, the process achieves precise shape control and minimizes material waste.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The alternating deposition and etching process creates different qualities of filling material distribution: dense vertical filling within the gap and removable lateral overgrowth outside the gap. This local quality differentiation enables precise control over where material is retained and where it is removed.

Inventive Principle:

Principle #3Local quality

3Manufacturing precision

If multiple deposition and etching cycles are performed, then voids and seams are avoided, but the manufacturing time increases

Engineering Contradiction:

Improvevoid and seam preventionVSAvoidmanufacturing efficiency

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

Each deposition cycle deposits material to a predetermined height before lateral overgrowth occurs. By performing this preliminary vertical deposition action, the process ensures complete gap filling from the bottom up, preventing void and seam formation while controlling the number of cycles needed.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces conventional single-step mechanical deposition with a controlled sequence of deposition and etching actions. This substitution enables precise atomic-level control over material placement, ensuring complete filling without defects while optimizing the number of cycles through automated process control.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 effectively fills gaps with minimal voids or seams, suitable for aspect ratios ranging from 1 to 10, ensuring complete and seamless filling of semiconductor structures.

Implementation Method 1

performing a deposition process to deposit a filling material which has a first portion on the bottom surface of the gap

Methodology Applied

Scientific EffectPhysical Vapour Deposition: Physical Vapour Deposition

Implementation Method 2

performing a deposition process to deposit a filling material which has a first portion on the bottom surface of the gap

Methodology Applied

Scientific EffectChemical Vapour Deposition: Chemical Vapour Deposition

Implementation Method 3

performing an etching back process to etch back the filling material until the second portion and an overhang part of the third portion which overhangs the gap are removed

Methodology Applied

Scientific EffectChemical Etching:

Data Source

PatentUS20260090347A1Gap filling method in semiconductor manufacturing process

Publication Date: 2026.03.26 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A method for filling a gap in a semiconductor structure includes: forming the gap between two raised portions of the semiconductor structure, the gap having a bottom surface and two lateral surfaces each extending upwardly from the bottom surface along one of the raised portions to terminate at an upper surface of a corresponding one of the raised portions; and forming a filler element in the gap in a bottom-up manner that avoids the filler element being formed laterally.