Plasma-Treated Metal Adhesion Layer for Uniform Metal Plug Filling
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Solution Overview
Problem
The existing titanium silicon nitride (TiSiN) coating used to improve adhesion between metal plugs and epitaxial regions in semiconductor devices suffers from de-wetting, leading to non-uniform nucleation and poor adhesion, resulting in increased contact resistance and voids, which degrade the performance of semiconductor devices.
Innovation Solution
A thin metal adhesion layer with a nitrogen-based plasma treatment is applied to the bottom and sidewalls of the trench before forming the metal plug, modifying the phase composition to a (111) dominant phase, enhancing adhesion by increasing interfacial nitrogen density and reducing voids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a titanium silicon nitride (TiSiN) coating is used to improve adhesion between metal plugs and epitaxial regions, then adhesion is improved, but de-wetting occurs leading to non-uniform nucleation and poor adhesion
Solution Approach 1:
A titanium nitride layer is formed on the titanium silicon nitride coating before forming the metal plug. This preliminary action modifies the surface properties and phase composition in advance, preventing de-wetting and ensuring uniform nucleation of the metal plug, thereby resolving the adhesion uniformity problem while maintaining strong adhesion
Solution Approach 2:
The phase composition of the titanium nitride layer is controlled to achieve a (111) dominant phase structure. This parameter change in crystal orientation improves the wetting properties and adhesion uniformity of the metal plug, eliminating the de-wetting issue while preserving the strong adhesion provided by the TiSiN coating
2Strength
If a TiSiN coating is applied to enhance metal plug adhesion, then adhesion is improved, but voids form between the sidewalls and metal plug, increasing contact resistance
Solution Approach 1:
The titanium nitride layer is formed as a preliminary step before metal plug deposition. This layer acts as an intermediate structure that ensures uniform coverage and prevents void formation at the interface between the metal plug and trench sidewalls, thereby reducing contact resistance while maintaining adhesion
Solution Approach 2:
By controlling the phase composition to achieve a (111) dominant phase in the titanium nitride layer, the surface energy and wetting characteristics are optimized. This parameter change prevents void formation and ensures low contact resistance, resolving the manufacturing precision issue
3Reliability
If a metal adhesion layer with plasma treatment is used to reduce voids, then adhesion is improved and voids are reduced, but process complexity increases
Solution Approach 1:
The titanium nitride layer serves as an intermediary between the titanium silicon nitride coating and the metal plug. This intermediate layer, formed through plasma-enhanced chemical vapor deposition, provides the necessary adhesion improvement and void reduction while integrating smoothly into the existing process flow, minimizing the increase in process complexity
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 solution significantly reduces voids and defects, improving adhesion between the metal adhesion layer and the metal plug, thereby enhancing semiconductor manufacturing yields without increasing process complexity.
Implementation Method 1
A nitrogen-based plasma may be used to modify the phase composition of the metal adhesion layer to increase adhesion between the metal adhesion layer and the metal plug
Implementation Method 2
the nitrogen-based plasma may cause a shift or transformation of the phase composition of the metal adhesion layer from being roughly equally composed of a (111) phase and a (200) phase to being composed of a (111) dominant phase
Data Source
AI summary
A metal adhesion layer may be formed on a bottom and a sidewall of a trench prior to formation of a metal plug in the trench. A plasma may be used to modify the phase composition of the metal adhesion layer to increase adhesion between the metal adhesion layer and the metal plug. In particular, the plasma may cause a shift or transformation of the phase composition of the metal adhesion layer to cause the metal adhesion layer to be composed of a (111) dominant phase. The (111) dominant phase of the metal adhesion layer increases adhesion between the metal adhesion layer.