Stepped Metal Interconnect Structure for Plasma Damage Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing anisotropic etch processes used in semiconductor manufacturing often cause plasma damage to underlying metal interconnect structures and semiconductor devices, leading to electrical failures and performance degradation.
Innovation Solution
The implementation of stepped metal interconnect structures, where only the metallic compound material portions are exposed during the formation of openings through a dielectric material layer, reduces plasma damage by using a metallic barrier liner with high resistivity to prevent excessive electrical current flow and oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an anisotropic etch process is used to pattern openings through an overlying insulating layer, then the openings can be effectively patterned, but plasma damage occurs to underlying metal interconnect structures causing electrical failures
Solution Approach 1:
A metallic compound material layer (such as tantalum nitride or tungsten nitride) is introduced as an intermediary barrier between the metal interconnect and the plasma environment. This intermediate layer has high electrical resistivity that limits current flow during plasma exposure, protecting the underlying metal from damage while allowing the etch process to proceed effectively.
Solution Approach 2:
The electrical resistivity parameter of the barrier layer is specifically optimized to be high enough to prevent excessive current flow during plasma exposure, yet low enough to maintain electrical connectivity. By changing the material composition and resistivity parameters, the system achieves both effective patterning and plasma damage resistance.
2Reliability
If a metallic barrier liner is used to prevent plasma damage, then electrical reliability improves, but the device structure becomes more complex
Solution Approach 1:
The metallic compound material layer serves multiple functions simultaneously: it acts as a diffusion barrier, an adhesion layer, and most importantly, a plasma damage resistance layer due to its high electrical resistivity. This multi-functionality reduces the need for additional specialized layers, thereby limiting the increase in structural complexity.
Solution Approach 2:
The interconnect structure uses composite material systems combining metals (such as copper or aluminum) with metallic compounds (such as tantalum nitride or tungsten nitride). This composite approach integrates protective and functional properties within a unified structure, avoiding the need for separate protective layers and simplifying the overall device architecture.
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 reduces plasma-induced damage to semiconductor devices and suppresses oxidation of metal interconnect structures, thereby enhancing the reliability and performance of the underlying electrically connected devices.
Implementation Method 1
previously formed metal interconnect structures may suffer undesirable plasma damage during an anisotropic etch process
Implementation Method 2
using a metallic barrier liner with high resistivity to prevent excessive electrical current flow
Implementation Method 3
suppresses oxidation of metal interconnect structures
Data Source
AI summary
A device structure may include an interconnect-level dielectric material layer located over a substrate, a first metal interconnect structure embedded in the interconnect-level dielectric material layer and including a first metallic barrier liner and a first metallic fill material portion, and an overlying dielectric material layer. An opening in the overlying dielectric material layer may be formed entirely within an area of the first metallic barrier layer and outside the area of the first metallic fill material portion to reduce plasma damage. A second metal interconnect structure contacting a top surface of the first metallic barrier liner may be formed in the opening. An entirety of a top surface the first metallic fill material portion contacts a bottom surface of the overlying dielectric material layer.