Selective Deposition of Metallic Films on Copper Surfaces
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in semiconductor fabrication is the difficulty in achieving selective deposition of metallic films on metallic surfaces while avoiding deposition on silicon-containing materials, which is crucial for reducing electromigration in copper interconnects and maintaining dielectric integrity, as existing methods lack sufficient selectivity and require complex patterning steps.
Innovation Solution
The process involves passivating a reaction chamber and subjecting a substrate to surface treatments, including plasma exposure, to selectively deposit metallic films, such as tungsten, on copper or cobalt surfaces relative to silicon surfaces, using precursors like silicon or boron, with a selectivity of greater than 50% and up to 100%, thereby avoiding deposition on silicon-containing materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If gentle surface treatments such as thermal or radical treatments are used to prepare surfaces for selective deposition, then surface terminations are provided, but selectivity is lost due to inadequate surface preparation
Solution Approach 1:
The patent changes the parameters of surface treatment by using plasma exposure followed by atomic layer deposition (ALD) to form a controlled silicon-containing layer. This transforms the surface state from inadequately prepared to optimally prepared for selective metal deposition, achieving both high selectivity and manufacturing feasibility through parameter optimization of the treatment process
Solution Approach 2:
The patent introduces an intermediary silicon-containing layer formed by ALD between the metal surface and the metallic film to be deposited. This intermediary layer acts as a mediator that enables selective deposition on metal surfaces while preventing deposition on silicon-containing dielectric surfaces, thus resolving the selectivity issue without requiring complex patterning
2Reliability
If selective metal cap deposition is attempted on metallic surfaces versus dielectric surfaces, then electromigration resistance is improved, but the process becomes challenging due to difficulty in achieving good selectivity
Solution Approach 1:
The patent uses an ALD-formed silicon-containing layer as an intermediary that creates the necessary surface chemistry for selective metal deposition. This intermediary approach simplifies the overall process by eliminating the need for complex self-aligned patterning steps while maintaining high selectivity, thus improving reliability without proportionally increasing device complexity
Solution Approach 2:
The patent performs preliminary surface preparation using plasma exposure and ALD to form a controlled silicon-containing layer before metal deposition. This preliminary action ensures that the surface is optimally prepared for selective deposition, enabling high electromigration resistance through a more straightforward process sequence rather than relying on complex in-situ patterning
3Manufacturing precision
If complex patterning steps are used to achieve selective metal deposition, then deposition selectivity is improved, but processing time and cost increase
Solution Approach 1:
The patent replaces complex patterning steps with a simpler ALD-based approach using a silicon-containing intermediary layer. This methodology achieves high deposition selectivity through material-specific surface chemistry rather than geometric patterning, significantly reducing processing steps, time, and cost while maintaining manufacturing precision
Solution Approach 2:
The patent substitutes mechanical/physical patterning methods with a chemical approach using ALD and plasma treatment. Instead of using lithography and etching to create patterns, the invention uses chemical vapor deposition to create a selective surface layer that directs metal deposition, replacing complex mechanical patterning systems with a more efficient chemical process
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 enhances the selectivity of metallic film deposition, reduces the need for additional processing steps, and improves the mean time to failure of copper interconnects by minimizing electromigration, while also saving time and costs associated with substrate processing.
Implementation Method 1
subjecting the substrate to a first surface treatment process comprising exposing the substrate to a plasma
Implementation Method 2
the passivation layer is formed by a vapor deposition process
Implementation Method 3
the passivation layer is formed by a plasma enhanced chemical vapor deposition (PECVD) process
Implementation Method 4
The passivation layer comprises SiN
Data Source
AI summary
Metallic layers can be selectively deposited on one surface of a substrate relative to a second surface of the substrate. In some embodiments, the metallic layers are selectively deposited on a first metallic surface relative to a second surface comprising silicon. In some embodiments the reaction chamber in which the selective deposition occurs may optionally be passivated prior to carrying out the selective deposition process. In some embodiments selectivity of above about 50% or even about 90% is achieved.