Electrolyte Nanoparticles for Selective Metal Removal
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Solution Overview
Problem
Current semiconductor processing methods for removing conductive metals from substrates, such as CMP and ECMP, face challenges with mechanical stress on brittle low-k dielectrics, residual metal islands due to electrical contact disruptions, and hardware complexities, leading to issues like 'dishing' and delamination.
Innovation Solution
The use of an electrolyte solution with nanoparticles more noble than the conductive metal, dispersed in a chemically compatible solvent, facilitates selective removal of conductive metals without surface contact or external electric potential, utilizing galvanic reactions to dissolve the metal in the presence of dielectric materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If CMP process is used to remove excess conductive material, then material removal is achieved, but mechanical stress causes dishing and scratching of copper interconnect and erosion of insulating layer
Solution Approach 1:
The patent replaces the mechanical CMP system with an electrolytic system that uses electrochemical reactions instead of mechanical abrasion. The electrolytic liquid with dispersed particles enables selective removal of conductive material through electrochemical dissolution, eliminating mechanical contact and associated damage such as dishing, scratching, and layer erosion.
Solution Approach 2:
The patent introduces an electrolytic liquid containing dispersed particles as an intermediary medium between the conductive material and the removal process. This intermediary enables selective electrochemical removal through galvanic coupling between the dispersed particles and the conductive material, allowing material removal without direct mechanical contact that would cause damage.
2Productivity
If high abrasive concentration is used in CMP slurry to remove barrier material, then barrier material removal is improved, but copper interconnect and insulating layer are damaged
Solution Approach 1:
The patent replaces mechanical abrasion with high abrasive concentration with an electrolytic removal mechanism. The electrolytic liquid with dispersed particles creates galvanic couples that selectively dissolve barrier material through electrochemical reactions, achieving high removal rates without the mechanical damage caused by high abrasive concentrations.
Solution Approach 2:
The patent changes the removal mechanism from mechanical (abrasive-based) to electrochemical (electrolytic). By adjusting parameters such as electrolyte composition, particle size distribution, and electrical potential, the process achieves selective barrier material removal while preserving the copper interconnect and insulating layer from mechanical damage.
3Object-affected harmful factors
If ECMP process is used to reduce downforce, then mechanical stress on substrate is reduced, but hardware complexity and electrical contact requirements increase
Solution Approach 1:
The patent replaces the ECMP mechanical-electrical hybrid system with a purely chemical/electrolytic system. The electrolytic liquid with dispersed particles enables material removal through galvanic coupling without requiring complex electrical contact hardware or external power supplies, simplifying the overall system while maintaining low mechanical stress benefits.
Solution Approach 2:
The patent enables the electrolytic liquid to self-generate the necessary electrochemical reactions through the galvanic coupling between dispersed particles and conductive material. This self-service mechanism eliminates the need for external electrical contact hardware and power supplies required by ECMP, reducing device complexity while maintaining low mechanical stress.
4Object-affected harmful factors
If electrolytic process is used to remove conductive material, then mechanical stress is eliminated, but residual metal islands remain when electrical contact is disrupted
Solution Approach 1:
The patent uses dispersed particles in the electrolytic liquid as intermediaries that maintain continuous galvanic coupling with the conductive material. These particles ensure complete material removal by preventing open circuits and residual metal islands, achieving both low mechanical stress and high manufacturing precision.
Solution Approach 2:
The patent optimizes parameters such as particle size distribution, particle concentration, and electrolyte composition to ensure complete electrochemical removal of conductive material. These parameter adjustments prevent residual metal islands by maintaining continuous electrochemical activity throughout the material removal process, achieving complete removal without mechanical stress.
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 allows for efficient, low-stress removal of conductive metals relative to dielectric materials, eliminating the need for abrasive components and external potentials, reducing hardware requirements, and preventing damage to substrate structures, thus enhancing the precision and cost-effectiveness of the process.
Implementation Method 1
utilizing galvanic reactions to dissolve the metal in the presence of dielectric materials
Data Source
AI summary
An electrolyte solution, methods, and systems for selectively removing a conductive metal from a substrate are provided. The electrolyte solution comprising nanoparticles that are more noble than the conductive metal being removed, is applied to a substrate to remove the conductive metal selectively relative to a dielectric material without application of an external potential or contact of a processing pad with a surface of the substrate. The solutions and methods can be applied, for example, to remove a conductive metal layer (e.g., barrier metal) selectively relative to a dielectric material and to a materially different conductive metal (e.g., copper interconnect) without application of an external potential or contact of a processing pad with the surface of the substrate.