Source-Drain Contact Structure With Embedded Dielectric Planarization
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Solution Overview
Problem
The challenge of forming reliable semiconductor devices at smaller sizes is exacerbated by the increasing complexity of fabrication processes due to decreasing feature sizes, which complicates the formation of reliable semiconductor devices.
Innovation Solution
A method involving the formation of a dielectric structure embedded in the contact structure, allowing for more flexible selection of metals and chemicals in the planarization process, reducing processing time and costs while preventing peeling issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature sizes continue to decrease to increase functional density, then production efficiency increases and costs decrease, but fabrication process complexity increases and reliability decreases
Solution Approach 1:
The contact structure is segmented into multiple functional layers including a metal layer, a dielectric layer, and a liner layer. This segmentation allows each layer to be optimized independently for its specific function, simplifying the overall fabrication process despite smaller feature sizes by breaking down the complex contact formation into manageable sequential steps.
Solution Approach 2:
The dielectric structure is formed and embedded within the contact structure before final planarization and metal deposition steps. This preliminary formation of the dielectric framework provides a stable foundation that guides subsequent processing steps, reducing the complexity of forming reliable contacts at smaller dimensions.
2Reliability
If conventional contact structures are used with metal filling, then electrical connectivity is achieved, but peeling issues occur and material selection is limited
Solution Approach 1:
A dielectric structure is introduced as an intermediary component within the contact structure, embedding the metal conductive element within the dielectric matrix. This intermediary dielectric layer prevents direct metal-to-metal contact and associated peeling issues while providing mechanical support and electrical isolation, thereby improving reliability and enabling greater flexibility in metal and chemical selection during planarization.
3Manufacturing precision
If standard planarization processes are applied, then surface flatness is achieved, but processing time increases and peeling occurs
Solution Approach 1:
Instead of applying planarization to a traditional metal-filled contact structure, the invention inverts the approach by forming the dielectric structure first and embedding it within the contact opening, then completing planarization. This inverted sequence allows the softer dielectric material to be planarized more easily and quickly without causing metal peeling, achieving surface flatness while reducing processing time.
Data Source
AI summary
A semiconductor device structure includes a gate structure formed over a substrate. The semiconductor device structure also includes a source/drain structure formed beside the gate structure. The semiconductor device structure further includes a contact structure formed over the source/drain structure. The semiconductor device structure also includes a first cap layer formed over the contact structure. The semiconductor device structure further includes a dielectric structure extending from a top surface of the first cap layer into the contact structure. The dielectric structure and the source/drain structure are separated by the contact structure.