PEALD Tantalum Barrier Layer High Aspect Ratio Uniformity
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Solution Overview
Problem
The deposition of Ta-containing films using physical vapor deposition (PVD) is non-uniform in structures with high aspect ratios, leading to thin or non-existent film layers on sidewalls and bottoms of trenches, which can result in inadequate barrier properties and adhesion issues in semiconductor manufacturing.
Innovation Solution
A plasma enhanced atomic layer deposition (PEALD) system is employed to form thin, conformal Ta-containing films, such as tantalum (Ta), tantalum nitride (TaN), and tantalum carbon nitride (TaCN) layers, using a process that alternately introduces Ta-containing precursors and purge gases in a plasma environment, allowing for precise control of film thickness and composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If physical vapor deposition (PVD) is used to deposit Ta-containing films, then the deposition process is simple and fast, but the film deposition is non-uniform in structures with high aspect ratios, resulting in thin or non-existent film layers on sidewalls and bottoms of trenches
Solution Approach 1:
The patent transitions from physical vapor deposition to plasma-enhanced chemical vapor deposition, fundamentally changing the deposition mechanism parameters. This allows the use of reactive plasma species and controlled chemical reactions to achieve uniform film deposition in high aspect ratio structures while maintaining acceptable deposition rates through optimized plasma power and gas flow parameters
2Temperature
If plasma enhanced chemical vapor deposition (PECVD) is used to deposit films at lower temperatures, then the deposition temperature is reduced, but the film-forming reactions require plasma excitation which adds process complexity
Solution Approach 1:
The patent introduces plasma as an intermediary to enable low-temperature deposition. The plasma provides activated species and energy to drive chemical reactions at temperatures that would otherwise be insufficient, while the sequential ALD process steps provide the structural framework to manage the overall process complexity
3Manufacturing precision
If atomic layer deposition (ALD) is used to form ultra-thin films with improved uniformity and control, then the film thickness uniformity and conformality are enhanced, but the deposition process requires alternating introduction of multiple process gases which increases process time
Solution Approach 1:
The patent implements continuous plasma exposure throughout the ALD cycle, with plasma present during precursor pulse, purge, and reaction phases. This continuous plasma action maintains reactive species on the surface throughout the cycle, enabling uniform deposition without requiring separate plasma activation steps, thereby reducing overall process time while maintaining ALD's superior uniformity and conformality
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 PEALD system achieves uniform and conformal deposition of Ta-containing films, enhancing barrier properties and adhesion on complex geometries while minimizing damage to underlying dielectric layers, effectively preventing metal diffusion and ensuring consistent film formation across high aspect ratio structures.
Implementation Method 1
In PECVD, plasma is used to alter or enhance the film deposition mechanism. For instance, plasma excitation generally allows film-forming reactions to proceed at temperatures that are significantly lower than those typically required to produce a similar film by thermally excited CVD.
Implementation Method 2
A plasma enhanced atomic layer deposition (PEALD) system is employed to form thin, conformal Ta-containing films
Data Source
AI summary
A method of forming a tantalum containing multi-layer film. In one embodiment, the method includes disposing a substrate in a process chamber, heating the substrate, exposing the substrate to a tantalum containing precursor to adsorb at least a portion of the tantalum containing precursor on a surface of the substrate, purging the process chamber with a purge gas, and exposing the substrate to a process space comprising helium and hydrogen ionized at a first radio frequency power to form a first tantalum containing layer on the surface. The method further includes exposing the substrate to the tantalum containing precursor to adsorb at least a portion of the precursor on the first tantalum containing layer, purging the process chamber with the purge gas, and exposing the substrate to the process space at a second radio frequency power to form a second tantalum containing layer, where the second radio frequency power is different from the first radio frequency power.