Dual Surface Passivation for Post-CMP Copper Queue Time Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As technology nodes advance, maintaining the integrity of copper surfaces post-CMP becomes challenging due to oxidation and diffusion issues, which affect the reliability and performance of semiconductor structures, particularly at metal pitches below 30 nm.
Innovation Solution
Applying a dual passivation layer system, where a first inhibitor selectively adsorbs on copper surfaces and a second inhibitor on dielectric surfaces, creating a protective environment that prevents copper diffusion and oxidation, extending the queue time between processing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If CMP process is used to planarize copper surfaces, then surface smoothness is improved, but copper surface integrity deteriorates due to oxidation and diffusion
Solution Approach 1:
The patent applies passivation layers immediately after CMP processing while the copper surface is still exposed and vulnerable. The first passivation layer is formed on the copper surface right after planarization, preventing oxidation and diffusion before they can occur during queue time. This preliminary protective action resolves the contradiction by maintaining surface integrity without compromising the smoothness achieved by CMP.
Solution Approach 2:
The patent introduces passivation layers as intermediary protective barriers between the copper surface and the oxidizing environment. The first passivation layer (such as nitrogen-containing compounds or sulfur-containing compounds) acts as a mediator that prevents direct contact between copper and atmospheric oxygen, while the second passivation layer on the dielectric surface prevents diffusion. This intermediary approach maintains both surface smoothness and integrity.
2Productivity
If queue time between CMP and subsequent processing is extended, then process flexibility is improved, but copper oxidation and diffusion increase
Solution Approach 1:
The patent applies passivation layers in advance during or immediately after CMP processing, creating a protective environment that enables extended queue times. The first passivation layer on copper and second passivation layer on dielectric are formed before the substrate enters the queue, allowing flexible scheduling without compromising surface stability. This preliminary protection resolves the contradiction between process flexibility and surface stability.
Solution Approach 2:
The patent creates an inert protective environment through passivation layers that chemically inhibit oxidation and diffusion reactions. The nitrogen-containing or sulfur-containing compounds on copper surface, and the dielectric surface treatment, effectively create a chemically inert barrier that stabilizes copper surfaces during extended queue times, enabling process flexibility without sacrificing reliability.
3Reliability
If dual passivation layer system is applied, then copper surface protection is improved, but process complexity increases
Solution Approach 1:
The patent segments the protection function into two distinct passivation layers: a first passivation layer applied to the copper surface and a second passivation layer applied to the dielectric surface. This segmentation allows each layer to perform its specific protective function independently - the first layer prevents copper oxidation while the second layer prevents diffusion. The segmented approach improves protection effectiveness while maintaining manageable process complexity through clear functional separation.
Solution Approach 2:
The patent applies different passivation treatments to different surfaces based on their specific protection needs. The copper surface receives nitrogen-containing or sulfur-containing compound treatment to prevent oxidation, while the dielectric surface receives a different treatment to prevent diffusion. This local quality approach optimizes protection for each surface type without unnecessarily complicating the overall process, as each treatment is tailored to its specific function.
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 dual passivation approach enhances queue time control, maintaining stable leakage current levels and enabling selective metal deposition, improving the reliability and performance of semiconductor structures.
Implementation Method 1
a first inhibitor selectively adsorbs on copper surfaces
Implementation Method 2
a second inhibitor on dielectric surfaces, creating a protective environment
Data Source
AI summary
A method includes providing a substrate comprising a metal surface and a dielectric surface in at least substantially a same horizontal plane. The substrate is treated with a first inhibitor. The first inhibitor covers the metal surface. The substrate is treated with a second inhibitor. The second inhibitor covers the dielectric surface. The first inhibitor is removed from the metal surface of the substrate.