Selective Cobalt Capping Layer for Semiconductor Adhesion
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Solution Overview
Problem
In semiconductor device manufacturing, the formation of openings for conductive features can damage capping and barrier layers, leading to adhesion issues and reliability concerns, particularly due to partial removal of these layers during etching processes.
Innovation Solution
A selective capping layer is formed over the conductive lines and barrier layers, which repairs damage caused by opening formation and improves adhesion between conductive lines and subsequent conductive vias, using materials like cobalt that have lower activation energy for binding to conductive surfaces than dielectric surfaces, allowing for selective deposition without additional masking or etching steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a selective capping layer is formed using materials with lower activation energy for binding to conductive surfaces, then adhesion between conductive lines and conductive vias is improved, but the process complexity increases due to selective deposition requirements
Solution Approach 1:
The patent applies local quality by using a capping layer material (such as cobalt) that has different binding characteristics for different surfaces. The material selectively binds to conductive surfaces (conductive lines and via walls) while avoiding binding to dielectric surfaces, creating locally optimized adhesion where needed without affecting other areas. This selective binding behavior is achieved through the material's lower activation energy for binding to conductive surfaces compared to dielectric surfaces.
2Productivity
If conventional etching processes are used to form openings, then conductive features can be formed, but damage to capping and barrier layers occurs leading to adhesion issues
Solution Approach 1:
The patent applies preliminary action by forming the capping layer over the conductive lines and barrier layers before the opening formation process. This pre-formed capping layer serves as a protective layer that prevents damage to the underlying capping and barrier layers during the subsequent etching process to form openings for conductive vias. The capping layer is deposited in advance to ensure the structural integrity and adhesion properties of the underlying layers are preserved.
3Reliability
If additional masking or etching steps are added to repair damaged layers, then layer integrity can be maintained, but manufacturing time and process steps increase
Solution Approach 1:
The patent applies self-service by utilizing the selective deposition capability of the capping layer material to automatically repair damaged layers without requiring additional masking or etching steps. When the capping layer is deposited, it selectively binds to exposed conductive surfaces in damaged areas, self-repairing the layer integrity through its inherent material properties. This eliminates the need for separate repair processes, as the system uses its own deposition mechanism to restore integrity where damage occurs.
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 selective capping layer enhances the electromigration characteristics and reliability of semiconductor devices by repairing damaged layers and ensuring better adhesion, thereby improving the overall performance and integrity of the device.
Implementation Method 1
using materials like cobalt that have lower activation energy for binding to conductive surfaces than dielectric surfaces, allowing for selective deposition without additional masking or etching steps
Data Source
AI summary
Embodiments of the present disclosure include a semiconductor device and methods of forming the same. A representative embodiment includes a method of forming a semiconductor device that includes a first conductive feature over a substrate, a dielectric layer over the conductive feature, and an opening through the dielectric layer to the first conductive feature. The method further includes selectively forming a first capping layer over the first conductive feature in the opening, and a second conductive feature on the first capping layer.