MOL Interconnect Structure With Ruthenium Oxide Diffusion Barrier
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing integrated circuit manufacturing processes face challenges with high contact resistance, void formation, and reliability issues due to oxidation and diffusion of metal liners, particularly in middle-of-the-line (MOL) interconnect structures, which are exacerbated by the use of traditional materials like tungsten and cobalt.
Innovation Solution
The introduction of a ruthenium-based intermixing barrier layer formed through annealing, eliminating the need for glue and barrier layers, which enhances adhesion and prevents diffusion, thereby reducing contact resistance and void formation, and simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional materials like tungsten and cobalt are used in MOL interconnect structures, then structural integrity is maintained, but contact resistance increases and reliability deteriorates due to oxidation and diffusion of metal liners
Solution Approach 1:
A ruthenium oxide intermixing barrier layer is introduced as an intermediary between the metal liner and the dielectric layer. This barrier layer prevents direct contact between the metal liner and oxygen-containing environments, thereby preventing oxidation. It also acts as a diffusion barrier to prevent metal liner atoms from diffusing into the dielectric layer, solving both oxidation and diffusion problems simultaneously.
Solution Approach 2:
The patent uses a composite structure consisting of a ruthenium oxide intermixing barrier layer combined with a metal liner (tungsten or cobalt). The ruthenium oxide layer provides protective functions while the metal liner provides structural integrity and conductivity, creating a composite material system that overcomes the limitations of traditional single-material approaches.
2Reliability
If glue and barrier layers are used in traditional MOL processes, then adhesion and diffusion prevention are achieved, but device complexity and manufacturing process complexity increase
Solution Approach 1:
The patent merges the functions of the glue layer and the barrier layer into a single ruthenium oxide intermixing barrier layer. This consolidated layer simultaneously provides adhesion between the metal liner and dielectric layer, prevents diffusion of metal atoms, and protects against oxidation, thereby reducing the total number of layers and simplifying the manufacturing process.
Solution Approach 2:
The ruthenium oxide intermixing barrier layer is designed to perform multiple functions: it provides adhesion, prevents diffusion, and protects against oxidation. This multi-functional layer replaces multiple separate layers (glue layer and barrier layer), reducing device complexity while maintaining or improving protective and adhesive functions.
3Reliability
If ion implantation processes are used to prevent diffusion, then diffusion prevention is achieved, but manufacturing process complexity and time increase
Solution Approach 1:
The patent replaces the ion implantation process (a complex, time-consuming, and equipment-intensive process) with a ruthenium oxide intermixing barrier layer that provides diffusion prevention through its physical and chemical properties. The barrier layer inherently prevents diffusion without requiring additional processing steps, thereby improving productivity while maintaining diffusion prevention effectiveness.
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
The ruthenium oxide intermixing barrier layer improves contact resistance by up to 40% and enhances reliability by eliminating the need for ion implantation processes, while maintaining structural integrity during subsequent manufacturing steps.
Implementation Method 1
an intermixing barrier layer of ruthenium oxide disposed between the upper conductive plug and the upper ILD layer and acting as a homogeneous glue layer therebetween
Implementation Method 2
The intermixing barrier layer may be formed by an annealing process following a filling process of the ruthenium conductive plug
Implementation Method 3
The introduction of a ruthenium-based intermixing barrier layer formed through annealing, eliminating the need for glue and barrier layers, which enhances adhesion and prevents diffusion
Data Source
AI summary
In some embodiments, the present disclosure relates to an integrated circuit device. A transistor structure includes a gate electrode separated from a substrate by a gate dielectric and a pair of source/drain regions disposed within the substrate on opposite sides of the gate electrode. A lower conductive plug is disposed through a lower inter-layer dielectric (ILD) layer and contacting a first source/drain region. A capping layer is disposed directly on the lower conductive plug. An upper inter-layer dielectric (ILD) layer is disposed over the capping layer and the lower ILD layer. An upper conductive plug is disposed through the upper ILD layer and directly on the capping layer.