ULK Dielectric Trench Surface Modification via Plasma Carbonization
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Solution Overview
Problem
The high roughness and porous nature of ultra-low-dielectric (ULK) layers in semiconductor interconnect structures lead to degradation in electric performance and reliability due to metal atom penetration, and the plasma etching process damages the ULK dielectric layer, causing unacceptable flatness and roughness issues.
Innovation Solution
A method involving an inert plasma treatment, carbonization, and nitridation process is applied to the side surfaces of trenches in the ULK dielectric layer to form a SiCNH layer, which improves the interface morphology and prevents metal atom diffusion, followed by the formation of a diffusion barrier layer and a metal layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If plasma etching process is used to etch the ULK dielectric layer, then the trench can be formed, but the ULK dielectric layer is damaged causing high roughness and unacceptable flatness
Solution Approach 1:
The patent applies preliminary action by performing the inert plasma treatment process on the trench side surface before forming the diffusion barrier layer. This preliminary treatment modifies the ULK dielectric layer surface to reduce roughness and improve flatness, creating a better foundation for subsequent barrier layer formation and preventing metal atom penetration.
Solution Approach 2:
The inert plasma treatment process acts as an intermediary between the damaging plasma etching and the subsequent barrier layer formation. It modifies the damaged ULK surface without causing further damage, creating an intermediate state that allows for better interface morphology and reduced roughness while preserving the underlying structure.
2Reliability
If diffusion barrier layer is formed directly on the damaged ULK dielectric layer, then the metal interconnect structure can be formed, but metal atoms penetrate into the ULK dielectric layer degrading electric performance
Solution Approach 1:
The patent applies preliminary anti-action by using the inert plasma treatment process to preemptively address the roughness issue before the diffusion barrier layer is formed. This treatment creates a smoother surface that prevents metal atom penetration pathways, thereby protecting the ULK dielectric layer from degradation and maintaining electric performance.
Solution Approach 2:
The inert plasma treatment serves as an intermediary layer of protection between the metal atoms and the ULK dielectric layer. It modifies the surface properties to create a more effective barrier against metal atom penetration, enhancing the overall reliability of the metal interconnect structure.
3Adaptability or versatility
If the roughness of ULK dielectric layer is high, then the porous nature is maintained, but the interface between ULK dielectric layer and diffusion barrier layer has issues
Solution Approach 1:
The patent applies local quality by selectively treating only the trench side surface with inert plasma, leaving the bulk ULK dielectric layer properties unchanged. This localized treatment improves the interface quality and reduces roughness at the critical interface region while preserving the overall porous nature and low-k properties of the ULK material.
Solution Approach 2:
The inert plasma treatment is performed as a preliminary step before barrier layer formation, specifically targeting the interface region. This preliminary action improves the local quality of the interface without affecting the bulk properties of the ULK dielectric layer, maintaining the balance between porous nature and interface quality.
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 process reduces the surface roughness of the ULK dielectric layer, enhances the stability and electrical performance of the metal interconnect structure, and improves the overall reliability of the semiconductor structure.
Implementation Method 1
performing an inert plasma treatment process on side surface of the trench
Implementation Method 2
performing a carbonization process on the side surface of the trench
Implementation Method 3
performing a nitridation process on the side surface of the trench to form a SiCNH layer on the side surface of the trench
Data Source
AI summary
A method for forming a semiconductor structure is provided. The method includes providing a substrate; and forming an ultra-low-dielectric-constant (ULK) dielectric layer on a surface of the substrate. The method also includes etching the ultra-low-dielectric-constant dielectric layer to form a trench in the ultra-low-dielectric-constant dielectric layer; and performing an inert plasma treatment process on a side surface of the trench. Further, the method includes performing a carbonization process on the side surface of the trench; and performing a nitridation process on the side surface of the trench to form a SiCNH layer on the side surface of the trench.