Interconnect Liners for IGZO Integrated Circuits
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Solution Overview
Problem
Conventional barrier materials like tantalum and tantalum nitride can degrade the performance of IC devices when used with indium gallium zinc oxide (IGZO) channel materials, leading to conductivity issues between transistors and interconnects.
Innovation Solution
Implementing tungsten or other alternative barrier materials, such as titanium, titanium nitride, ruthenium, molybdenum, iridium, and platinum, as liners for metal interconnects to shield the inner barrier layers and prevent interaction with the channel material, along with additional layers like tantalum or tantalum nitride.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional barrier materials like tantalum and tantalum nitride are used with IGZO channel materials, then the interconnect structure provides copper diffusion barrier, but the barrier materials degrade the performance of IC devices by causing conductivity issues between transistors and interconnects
Solution Approach 1:
The patent introduces an intermediary liner layer (such as tungsten, titanium, ruthenium, or their nitrides) positioned between the copper interconnect and the traditional barrier materials (tantalum/tantalum nitride). This intermediary layer acts as a mediator that prevents direct interaction between the harmful barrier materials and the IGZO channel, thereby eliminating the conductivity degradation while maintaining the diffusion barrier function. The liner layer is deposited conformally on the interconnect structure before the outer barrier layers are applied.
Solution Approach 2:
The patent segments the traditional single-layer barrier structure into multiple distinct layers: an inner liner layer (tungsten/titanium/ruthenium or their nitrides) that contacts the interconnect, and outer barrier layers (tantalum/tantalum nitride) that provide the primary diffusion barrier. This segmentation allows each layer to perform its specific function independently - the inner liner protects the IGZO interface while the outer layers provide robust copper barrier protection.
2Stability of the object's composition
If copper interconnects are surrounded by barrier material to prevent diffusion, then copper diffusion is blocked, but the barrier material causes interaction degradation with IGZO channel material
Solution Approach 1:
The patent introduces an intermediary liner layer (such as tungsten, titanium, ruthenium, or their nitrides) positioned between the copper interconnect and the traditional barrier materials (tantalum/tantalum nitride). This intermediary layer acts as a mediator that prevents direct interaction between the harmful barrier materials and the IGZO channel, thereby eliminating the conductivity degradation while maintaining the diffusion barrier function. The liner layer is deposited conformally on the interconnect structure before the outer barrier layers are applied.
Solution Approach 2:
The patent creates a composite interconnect structure consisting of multiple material layers with complementary properties: the inner liner layer provides IGZO interface compatibility and adhesion, while the outer tantalum/tantalum nitride layers provide superior copper diffusion barrier properties. This composite structure combines the advantages of different materials to simultaneously achieve both IGZO compatibility and effective copper barrier protection.
Data Source
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AI summary
Described herein are integrated circuit devices with lined interconnects. Interconnect liners can help maintain conductivity between semiconductor devices (e.g., transistors) and the interconnects that conduct current to and from the semiconductor devices. In some embodiments, metal interconnects are lined with a tungsten liner. Tungsten liners may be particularly useful with semiconductor devices that use certain channel materials, such as indium gallium zinc oxide.