Metal Adhesion Layer Phase Control for Void-Free Plug Contacts
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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 TiSiN coating is used to improve adhesion, then adhesion between metal plug and epitaxial region is improved, but de-wetting occurs leading to non-uniform nucleation and poor adhesion
Solution Approach 1:
The patent applies nitrogen-based plasma treatment to modify the phase composition of the TiSiN coating, transforming it from a mixed-phase structure to a dominant (111) phase. This parameter change in crystal structure improves adhesion uniformity by preventing de-wetting while maintaining strong adhesion between the metal plug and epitaxial region.
Solution Approach 2:
The patent uses a composite structure consisting of TiSiN coating with modified phase composition combined with nitrogen-based plasma treatment. This composite approach creates a material with enhanced adhesion properties that prevents de-wetting and ensures uniform nucleation of the metal plug.
2Strength
If TiSiN coating is used, then adhesion is improved, but voids form between sidewalls and metal plug, increasing contact resistance
Solution Approach 1:
By changing the phase composition parameter of the TiSiN coating through nitrogen-based plasma treatment to achieve dominant (111) phase, the patent eliminates void formation between sidewalls and metal plug, thereby reducing contact resistance while maintaining adhesion.
3Strength
If TiSiN coating is applied, then adhesion is enhanced, but de-wetting leads to continuity degradation of the coating
Solution Approach 1:
The patent modifies the phase composition parameter of the TiSiN coating through nitrogen-based plasma treatment, transforming it to a dominant (111) phase. This change improves coating continuity and prevents de-wetting while maintaining enhanced adhesion properties.
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 effectively reduces de-wetting and voids, improving adhesion between the metal adhesion layer and the metal plug, thereby decreasing contact resistance and increasing semiconductor manufacturing yields without adding complexity to the process.
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.