Semiconductor Interconnect Structure With Selective Trench Insulation
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Solution Overview
Problem
Existing techniques for forming interconnect structures in semiconductor devices fail to adequately address variations in critical dimension and contact resistance due to instability of blocking layers during the deposition of insulating materials, leading to undesired deposition on metal surfaces.
Innovation Solution
A method involving the modification of the oxidation state of the metal surface using an aqueous solution containing NH4OH and H2O2, followed by deposition of a blocking layer, which stabilizes the blocking material during baking, allowing selective deposition of insulating material only on the trench sidewalls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a blocking layer is deposited on the metal surface to prevent insulating material deposition, then contact resistance is reduced, but the blocking layer becomes unstable during baking and allows undesired deposition on metal surfaces
Solution Approach 1:
The patent applies preliminary action by modifying the metal surface oxidation state before depositing the blocking layer. The aqueous solution treatment (NH4OH and H2O2) is performed in advance to create a stable surface condition that prevents blocking layer degradation during subsequent baking processes, thereby ensuring both low contact resistance and blocking layer stability.
Solution Approach 2:
The patent employs parameter changes by altering the oxidation state of the metal surface through chemical treatment. This parameter modification (from metallic state to oxidized state) creates a surface that is more compatible with the blocking layer material, preventing instability and undesired deposition during thermal processing while maintaining effective contact resistance reduction.
2Ease of manufacture
If insulating material is deposited in the trench to form an interconnect structure, then the interconnect structure is formed, but insulating material deposits on the metal surface increasing contact resistance
Solution Approach 1:
The patent uses an intermediary approach by introducing a blocking layer as a mediator between the metal surface and the insulating material. This blocking layer selectively prevents insulating material deposition on the metal surface while allowing trench filling, thereby enabling easy interconnect structure formation without increasing contact resistance.
Solution Approach 2:
The patent applies local quality by creating different surface properties in different locations. The metal surface is treated to have oxidation-resistant properties where contact is needed, while the trench sidewalls maintain their original properties for proper insulating material deposition. This localized differentiation ensures both ease of manufacture and low contact resistance.
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 ensures a significant reduction in contact resistance by preventing or minimizing the deposition of insulating material on the metal surface, thereby enhancing the integrity and performance of the interconnect structure.
Implementation Method 1
modifying an oxidation state of the metal using an aqueous solution
Implementation Method 2
forming a blocking layer on the bottom surface of the trench... preventing or minimizing the deposition of insulating material on the metal surface
Data Source
AI summary
An interconnect structure, which may be used for example in a semiconductor device, is disclosed. The interconnect structure includes a contact layer made of a metal; one or more dielectric layers on the contact layer, and a deposited layer made of an insulating material. The interconnect structure further includes a trench through the one or more dielectric layers so that a sidewall surface of the trench is formed by the one or more dielectric layers and a bottom surface of the trench is formed by a portion of the contact layer. The deposited layer is in the trench and a thickness of the insulating material on the sidewall surface of the trench is at least 2.1 times greater than a thickness of the insulating material on the bottom surface of the trench.