Selective Plating for High Aspect Ratio Interconnects

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Solution Overview

Problem

Simultaneously forming conductive interconnects in both high and low aspect ratio openings in semiconductor fabrication is challenging due to overfilling of conductive material in high aspect ratio openings, leading to excess material removal complications and waste, particularly during planarization processes.

Innovation Solution

Implementing selective plating techniques where high aspect ratio openings are initially filled with conductive material, followed by selective electroless plating under turbulent conditions to fill low aspect ratio openings without forming large bumps over the high aspect ratio openings, using stabilizers and controlled deposition conditions to prevent excess material deposition on planarized surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conductive material is deposited to fill low aspect ratio openings, then low aspect ratio openings are filled, but high aspect ratio openings become overfilled creating excess material

Engineering Contradiction:

Improvefilling precisionVSAvoidconductive material waste

Core Design Contradiction:

Manufacturing precisionVSLoss of substance

Solution Approach 1:

The patent applies partial action by depositing conductive material in controlled stages - first filling high aspect ratio openings to a specific level, then selectively filling low aspect ratio openings without completely filling them, and finally planarizing to remove excess material only where needed, thereby reducing overall material waste

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent segments the deposition process into multiple distinct steps with different objectives: initial deposition to fill high aspect ratio openings, selective deposition for low aspect ratio openings, and planarization. This segmentation allows precise control over material placement and reduces unnecessary material deposition

Inventive Principle:

Principle #1Segmentation

2Manufacturing precision

If conductive material is deposited to fill high aspect ratio openings, then high aspect ratio openings are filled, but large amounts of excess material are formed requiring removal

Engineering Contradiction:

Improveopening fill completenessVSAvoidplanarization complexity

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by first forming a barrier material layer before conductive material deposition, and by controlling the initial deposition to fill high aspect ratio openings to a predetermined level. This preliminary control prevents excessive material formation and simplifies subsequent planarization steps

Inventive Principle:

Principle #10Preliminary action

3Productivity

If simultaneous filling of high and low aspect ratio openings is attempted, then both opening types are targeted, but selective filling control is lost

Engineering Contradiction:

Improveconductive interconnect formation efficiencyVSAvoidselective filling control

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by creating different filling conditions for different opening types through selective deposition parameters. Low aspect ratio openings receive continued deposition after high aspect ratio openings are filled, while high aspect ratio openings are protected from further deposition through the planarization step, giving each opening type the specific treatment it needs

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 material waste and planarization-related defects by ensuring precise filling of low aspect ratio openings while minimizing excess material on high aspect ratio openings, thereby optimizing the use of conductive materials and reducing costs associated with removal and waste management.

Implementation Method 1

selective electroless plating under turbulent conditions to fill low aspect ratio openings

Methodology Applied

Scientific EffectElectroless plating: Electroplating

Implementation Method 2

selective electroless plating under turbulent conditions

Methodology Applied

Scientific EffectTurbulent flow: Turbulence

Data Source

PatentUS8431184B2Methods of forming electrically conductive structures

Publication Date: 2013.04.30 MICRON TECHNOLOGY INC

AI summary

Some embodiments include methods of forming conductive material within high aspect ratio openings and low aspect ratio openings. Initially, the high aspect ratio openings may be filled with a first conductive material while the low aspect ratio openings are only partially filled with the first conductive material. Additional material may then be selectively plated over the first conductive material within the low aspect ratio openings relative to the first conductive material within the high aspect ratio openings. In some embodiments, the additional material may be activation material that only partially fills the low aspect ratio opening, and another conductive material may be subsequently plated onto the activation material to fill the low aspect ratio openings.