Copper-Copper Interface Peeling Integrity via Plasma Descumming

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Solution Overview

Problem

Conventional copper-copper interfaces in integrated circuit devices often experience peeling issues, which degrade device performance due to the presence of copper oxide and fluoride layers that hinder intergrowth between copper layers, leading to a high percentage of flat zone interface regions.

Innovation Solution

The interface between copper layers is designed to have less than 50% flat zone interface regions by removing copper oxide and fluoride layers through a CF4/O2/N2 plasma descumming process, allowing for intergrowth and reducing peeling, with a combination of flat zone and intergrowth interface regions to maintain integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional copper-copper interfaces are used, then manufacturing is simpler, but peeling occurs at the interface degrading device performance

Engineering Contradiction:

Improveinterface peeling integrityVSAvoidinterface structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The interface structure is segmented into three distinct regions: a first copper layer, a second copper layer, and an intergrowth region between them. This segmentation allows each region to have optimized properties - the copper layers provide conductivity while the intergrowth region provides mechanical bonding, thereby preventing peeling without requiring complex external structures.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent merges the copper layers directly with each other through an intergrowth region, eliminating the need for intermediate barrier layers or adhesives. This merging approach creates a unified copper-copper interface that maintains both electrical conductivity and mechanical integrity, resolving the contradiction between simplicity and reliability.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If copper oxide and fluoride layers are present at the interface, then copper layers are protected from oxidation, but intergrowth between copper layers is hindered causing peeling

Engineering Contradiction:

Improveinterface intergrowth integrityVSAvoidcopper oxide and fluoride layer formation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and removes the harmful copper oxide and fluoride layers from the interface between copper layers. By eliminating these intermediate layers that prevent direct contact between copper surfaces, the invention enables proper intergrowth and bonding, thereby achieving reliable interface integrity without the protective oxide/fluoride barrier.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention converts the potentially harmful effect of copper oxidation into a benefit by using controlled oxidation during processing, then removing the oxide layer to create a clean interface. This approach ensures that copper layers are properly prepared for intergrowth while preventing the long-term degradation that would occur if oxide layers remained at the interface.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If flat zone interface regions dominate the interface, then manufacturing is easier, but peeling occurs due to lack of intergrowth

Engineering Contradiction:

Improveinterface peeling resistanceVSAvoidinterface formation complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies local quality by creating a specific intergrowth region with distinct properties between the copper layers. Rather than making the entire interface uniform, the intergrowth region is localized where direct copper-copper bonding is required, while other areas can have different characteristics. This localized approach ensures peeling resistance at critical interfaces without complicating the overall manufacturing process.

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 approach effectively eliminates peeling issues at copper-copper interfaces, enhancing the overall performance of integrated circuit devices by promoting intergrowth and maintaining interface integrity.

Implementation Method 1

performing a descumming process that utilizes a CF4/O2/N2 plasma

Methodology Applied

Scientific EffectPlasma: Plasma

Implementation Method 2

performing a descumming process that utilizes a CF4/O2/N2 plasma; removing a residual layer formed over the copper seed layer during the descumming process

Methodology Applied

Scientific EffectPlasma etching:

Data Source

PatentUS8344506B2Interface structure for copper-copper peeling integrity

Publication Date: 2013.01.01 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

An integrated circuit device is disclosed. An exemplary integrated circuit device includes a first copper layer, a second copper layer, and an interface between the first and second copper layers. The interface includes a flat zone interface region and an intergrowth interface region, wherein the flat zone interface region is less than or equal to 50% of the interface.