Semiconductor Contact Structure Nitridation for Void-Free Metal Plugs
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Solution Overview
Problem
As semiconductor devices shrink, existing contact structures face challenges in meeting conductivity and reliability requirements due to issues with adhesion layer thickness and spacing, leading to voids and electrical shorts in advanced technology nodes.
Innovation Solution
A novel surface treatment is introduced to form a uniform and ultrathin adhesion layer with a thickness less than 20 Å, along with nitrogen-rich areas and nitridation regions, which act as diffusion barriers to prevent metal plug reflow and electrical shorts, and ensure effective adhesion and barrier functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional adhesion layer formation methods are used, then the adhesion layer provides basic barrier function, but the layer thickness is insufficient to prevent metal plug reflow and electrical shorts in advanced technology nodes
Solution Approach 1:
A surface treatment step is performed before depositing the adhesion layer to modify the substrate surface properties. This preliminary action creates nitrogen-rich areas and nitridation regions that enhance subsequent adhesion layer formation and provide diffusion barriers, allowing for ultrathin layer thickness while maintaining reliability.
Solution Approach 2:
The patent changes the chemical composition and physical properties of the substrate surface through plasma treatment or ion implantation, creating nitrogen-rich regions that alter diffusion characteristics. This parameter change enables the adhesion layer to function effectively at ultrathin dimensions by modifying the underlying surface properties.
2Length of moving object
If the adhesion layer is made thinner to provide sufficient spacing for metal plug formation, then spacing requirements are met, but the barrier function against diffusion and reflow is compromised
Solution Approach 1:
The surface treatment creates localized nitrogen-rich areas and nitridation regions at specific locations where metal plugs will be formed. This local quality enhancement provides diffusion barriers precisely where needed, allowing the adhesion layer to be ultrathin while maintaining barrier function at critical interfaces.
Solution Approach 2:
The patent creates a composite structure consisting of the substrate, nitrogen-rich areas, nitridation regions, and adhesion layer. This composite material system provides enhanced barrier properties that enable ultrathin adhesion layer thickness while maintaining diffusion prevention capabilities.
3Manufacturing precision
If conventional surface treatment is applied, then basic surface preparation is achieved, but uniform and ultrathin adhesion layer formation with proper spacing is not realized
Solution Approach 1:
The patent replaces conventional mechanical or thermal surface preparation methods with plasma treatment or ion implantation. This substitution enables precise control over surface chemistry and creates the necessary nitrogen-rich regions for uniform ultrathin adhesion layer formation, achieving manufacturing precision that outweighs the added process step.
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 solution enhances the formation of void-free metal plugs and improves both electrical and reliability properties by providing sufficient spacing and preventing diffusion into surrounding layers, addressing the limitations of conventional techniques in advanced technology nodes.
Implementation Method 1
applying a plasma treatment to the sidewall of the dielectric layer and the top surface of the substrate to form a nitridation region
Implementation Method 2
applying a plasma treatment to the sidewall of the dielectric layer and the top surface of the substrate to form a nitridation region adjacent to a periphery of the silicide region
Implementation Method 3
depositing an adhesion layer on the dielectric layer and the silicide region... act as diffusion barriers to prevent metal plug reflow and electrical shorts
Data Source
AI summary
A method for forming a semiconductor contact structure is provided. The method includes depositing a dielectric layer over a substrate. The method also includes etching the dielectric layer to expose a sidewall of the dielectric layer and a top surface of the substrate. In addition, the method includes forming a silicide region in the substrate. The method also includes applying a plasma treatment to the sidewall of the dielectric layer and the top surface of the substrate to form a nitridation region adjacent to a periphery of the silicide region. The method further includes depositing an adhesion layer on the dielectric layer and the silicide region.