Ruthenium Deposition Using Two-Step Plasma Surface Conditioning
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Solution Overview
Problem
The deposition of ruthenium films in semiconductor manufacturing faces challenges such as achieving uniform and conformal deposition in high-aspect-ratio structures, formation of discontinuous films due to island formation, and compatibility issues with high processing temperatures, which affect electrical performance and reliability.
Innovation Solution
A method involving two plasma treatments is used to prepare the substrate surface for ruthenium deposition, including a nitrogen and hydrogen-containing first plasma to adsorb nitrogen-hydrogen species, followed by a hydrogen-free second plasma to create a gradient of surface properties, facilitating uniform ruthenium deposition from the bottom up, and a thermal chemical vapor deposition process to fill the opening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional deposition methods are used to deposit ruthenium in high-aspect-ratio structures, then the deposition process is simple, but uniform and conformal deposition cannot be achieved
Solution Approach 1:
The plasma treatment process is divided into multiple sequential steps: first plasma treatment with nitrogen and hydrogen containing gas, followed by second plasma treatment with hydrogen free plasma. This segmentation allows each plasma step to perform a specific function - the first plasma prepares the surface by adsorbing nitrogen-hydrogen species, while the second plasma creates the desired surface property gradient, collectively achieving uniform ruthenium deposition in high-aspect-ratio structures
Solution Approach 2:
The patent creates a gradient of surface properties through the two-step plasma treatment, where different regions of the substrate surface acquire different characteristics. The first plasma treatment adsorbs nitrogen-hydrogen species throughout, while the second hydrogen-free plasma selectively modifies upper portions of sidewalls, creating a spatial gradient that promotes uniform ruthenium deposition from bottom to top in high-aspect-ratio features
2Manufacturing precision
If ruthenium deposition is performed without surface treatment, then the process is simple, but discontinuous films form due to island formation
Solution Approach 1:
The patent applies preliminary plasma treatments before ruthenium deposition to modify the substrate surface properties. The first plasma treatment with nitrogen and hydrogen containing gas adsorbs nitrogen-hydrogen species on the surface, and the second hydrogen-free plasma further modifies the surface to create a gradient of properties. These preliminary actions prepare the surface to promote continuous film formation and prevent island formation during subsequent ruthenium deposition
3Productivity
If high processing temperatures are used for ruthenium deposition, then deposition rate is improved, but compatibility issues arise with other materials and thermal budget constraints
Solution Approach 1:
The patent modifies the surface chemical state through plasma treatment rather than relying on high temperature to achieve good deposition quality. By adsorbing nitrogen-hydrogen species and creating a surface property gradient through plasma treatment, the process enables effective ruthenium deposition at lower temperatures, thereby maintaining compatibility with other materials and adhering to thermal budget constraints while preserving adequate deposition rates
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 method enables void-free, uniform ruthenium deposition in high-aspect-ratio features, improving electrical performance and reliability by enhancing adhesion and controlling film morphology, while maintaining compatibility with other materials and thermal budgets.
Implementation Method 1
using a first plasma process, adsorbing nitrogen and hydrogen atoms to the bottom surface and sidewalls
Implementation Method 2
using a second plasma process, selectively removing hydrogen atoms from upper portions of the sidewalls
Implementation Method 3
using a thermal chemical vapor deposition process, depositing ruthenium into the opening after exposing the substrate to the second plasma
Data Source
AI summary
In one example, a method for depositing ruthenium includes forming an opening in a dielectric layer disposed over a substrate, exposing the substrate including the opening to a first plasma in a plasma processing chamber including nitrogen and hydrogen, and exposing the substrate including the opening to a second plasma in the plasma processing chamber. The second plasma is hydrogen free. The method includes depositing ruthenium into the opening after exposing the substrate to the second p