Manganese Cap Layer for Copper Interconnect Oxidation Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Copper-based interconnection lines in semiconductor devices face challenges such as copper diffusion into dielectric materials, oxidation, and poor adhesion due to copper oxide formation, leading to electromigration reliability issues and damage to low-k materials during plasma-based cleaning and deposition processes.
Innovation Solution
A manganese-based cap layer is deposited over copper-based interconnection lines without plasma-based processes to reduce oxidized copper regions and improve adhesion, followed by a second cap layer of silicon carbide or nitrogen-enriched silicon carbide to enhance barrier properties and prevent oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If plasma-based processes are used to remove copper oxide and improve adhesion, then adhesion between cap layer and copper interconnection is improved, but low-k dielectric materials are damaged
Solution Approach 1:
A manganese-based intermediate layer is deposited between the copper interconnection and the cap layer. This manganese layer serves as a mediator that reacts with copper oxide to form manganese oxide, thereby removing the harmful copper oxide without requiring plasma treatment that would damage the low-k dielectric materials.
Solution Approach 2:
The harmful copper oxide that normally requires plasma removal is instead converted into manganese oxide through a controlled reaction with the deposited manganese layer. This transforms the harmful substance into a beneficial intermediate compound that facilitates adhesion without damaging the surrounding dielectric materials.
2Use of energy by moving object
If copper-based interconnection lines are used to improve conductivity, then signal transmission efficiency is improved, but copper diffusion into dielectric material occurs causing unpredictable performance
Solution Approach 1:
A barrier material layer is deposited between the copper interconnection and the dielectric layer, serving as an intermediary that prevents copper diffusion into the dielectric material while maintaining the electrical conductivity benefits of copper interconnections.
Solution Approach 2:
The structure is segmented into distinct functional layers: copper interconnection layer, barrier material layer, and dielectric layer. This segmentation isolates the copper from the dielectric material, preventing harmful interactions while preserving the advantageous properties of each material.
3Use of energy by moving object
If copper-based interconnection lines are used to improve conductivity, then signal transmission efficiency is improved, but oxidation of copper occurs leading to poor adhesion
Solution Approach 1:
A manganese-based cap layer is deposited preliminarily over the copper interconnection before final cap layer deposition. This preliminary manganese layer reacts with any formed copper oxide, preventing it from interfering with the adhesion between the final cap layer and the copper interconnection.
Solution Approach 2:
The copper oxide that forms on the copper surface due to oxidation is converted into manganese oxide through reaction with the deposited manganese layer. This transformation eliminates the adhesion problems caused by copper oxide while utilizing the oxidation process itself.
4Productivity
If the cross-sectional area of metallic interconnect lines is reduced to increase current density, then device scaling is achieved, but electromigration reliability deteriorates
Solution Approach 1:
The interconnection structure uses a composite material system consisting of copper interconnection lines with manganese-based cap layers. This composite structure provides both the high conductivity of copper and the protective/adhesive properties of manganese, improving electromigration resistance while maintaining device scaling.
Solution Approach 2:
The manganese-based cap layer is deposited beforehand to cushion and protect the copper interconnection from oxidation and adhesion failures. This protective layer prevents the harmful effects that would otherwise accelerate electromigration in scaled-down interconnect structures.
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 improves electromigration reliability by eliminating copper oxide and preventing plasma damage to low-k materials, maintaining the intrinsic dielectric constant of low-k materials and extending the functional lifetime of semiconductor devices.
Implementation Method 1
A manganese-based cap layer is deposited over copper-based interconnection lines without plasma-based processes to reduce oxidized copper regions
Implementation Method 2
Copper is also highly sensitive to oxidation and easily forms a film of copper oxide, particularly during the numerous heating steps that are employed in the fabrication of semiconductor structures
Implementation Method 3
A manganese-based cap layer is deposited over copper-based interconnection lines
Data Source
AI summary
A semiconductor structure having a cap layer formed over a metalized dielectric layer is formed by depositing manganese on the surface of the metalized dielectric layer. The deposited manganese serves as a first cap layer to remove oxidation on the surface of the metalized dielectric layer. The presence of oxidation on the surface of the metalized dielectric layer can be delirious for performance of a device constructed out of the semiconductor structure. A second cap layer is then formed by depositing silicon carbide or nitrogen enriched silicon carbide over the first cap layer.