Interconnect Structure With Carbon Mask for Fully Aligned Vias

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Solution Overview

Problem

The reduction in size of semiconductor devices leads to nano-scale wiring, which poses challenges in alignment and overlay during the photolithography process, and existing methods struggle to effectively form reliable interconnect structures with reduced line widths.

Innovation Solution

A method involving the formation of a substrate with a first metal layer, a first insulating layer, and a carbon layer with an sp2 bonding structure, where the carbon layer is selectively deposited using CVD or PECVD, and a second insulating layer is formed to cover the first insulating layer, allowing for precise electrical connection between metal layers through a fully-aligned via integration process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If photolithography process is used for nano-patterning, then nano-scale wiring can be formed, but misalignment and overlay errors occur

Engineering Contradiction:

Improvewiring alignment precisionVSAvoidinterconnect structure reliability

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

A carbon layer with sp2 bonding structure is introduced as an intermediary mask layer between the photolithography patterning and the via formation process. This carbon layer enables selective deposition and serves as a reliable alignment reference, eliminating misalignment and overlay errors while maintaining nano-scale wiring precision.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The carbon layer is formed in advance before the via formation process. This preliminary action establishes a stable reference structure that guides subsequent deposition steps, ensuring precise alignment without requiring high-precision photolithography alignment procedures.

Inventive Principle:

Principle #10Preliminary action

2Volume of moving object

If line widths are reduced to nano-scale for high integration, then device size is reduced, but alignment and overlay control becomes difficult

Engineering Contradiction:

Improvedevice sizeVSAvoidalignment precision

Core Design Contradiction:

Volume of moving objectVSManufacturing precision

Solution Approach 1:

The carbon mask layer acts as an intermediary that decouples the alignment requirement from the final via dimensions. By using selective deposition on the carbon layer rather than photolithography alignment, the method achieves precise via placement even with reduced line widths, maintaining manufacturing precision while enabling device miniaturization.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If carbon layer with sp2 bonding structure is selectively formed, then selective deposition mask is achieved, but additional process steps are required

Engineering Contradiction:

Improveselective deposition capabilityVSAvoidprocess complexity

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The carbon layer is formed by changing deposition parameters (using CVD or PECVD with specific carbon-containing gases) to selectively deposit carbon with sp2 bonding structure on metal surfaces. This parameter change enables the carbon layer to serve as an effective selective mask without requiring additional complex patterning equipment or processes.

Inventive Principle:

Principle #35Parameter changes

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 enhances the formation of interconnect structures by improving alignment and reducing defects, while the carbon layer with sp2 bonding structure acts as a mask for selective deposition of insulating layers and helps in reducing electromigration effects by acting as a capping layer.

Implementation Method 1

The selectively forming the carbon layer may include depositing the carbon layer on the first metal layer through a deposition process using chemical vapor deposition (CVD) or plasma enhanced CVD (PECVD)

Methodology Applied

Scientific EffectChemical Vapour Deposition: Chemical Vapour Deposition

Implementation Method 2

Methodology Applied

Scientific EffectPlasma Enhanced Chemical Vapour Deposition: Plasma Enhanced Chemical Vapour Deposition

Implementation Method 3

the carbon layer with sp2 bonding structure acts as a mask for selective deposition of insulating layers

Methodology Applied

Scientific EffectSelective Deposition:

Implementation Method 4

helps in reducing electromigration effects by acting as a capping layer

Methodology Applied

Scientific EffectCapping Layer Effect:

Data Source

PatentUS12080595B2Method of forming interconnect structure

Publication Date: 2024.09.03 SAMSUNG ELECTRONICS CO LTD

AI summary

Provided is a method of forming an interconnect structure. The method includes preparing a substrate including a first metal layer and a first insulating layer, selectively forming a carbon layer having an sp2 bonding structure on the first metal layer, selectively forming a second insulating layer on the first insulating layer, forming a third insulating layer to cover the second insulating layer, and forming a second metal layer electrically connected to the first metal layer.