Segmented Contact Hole Structure for Lower Plug Resistance
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Solution Overview
Problem
As semiconductor integration levels increase, reducing contact resistance in conductive plugs becomes challenging due to the decreasing dimensions of integrated circuits and the corresponding reduction in hole dimensions for conductive plug arrangement, leading to higher contact resistance.
Innovation Solution
A contact structure and method involving a contact hole with a first and second hole segment, where the second hole segment is positioned away from the substrate, forming an inverted wine cup shape, allowing for a larger contact area with the substrate, and a conductive plug with a first and second conductive segment, facilitating reduced contact resistance through enhanced area contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the dimension of the integrated circuit is reduced to achieve higher integration level, then the integration level is improved, but the hole dimension for conductive plug arrangement is reduced, leading to increased contact resistance
Solution Approach 1:
The contact hole is divided into two segments: a first hole segment penetrating the insulating dielectric layer to the substrate, and a second hole segment positioned above the first hole segment with its orthogonal projection within the first orthogonal projection. This segmentation allows the conductive plug to have an enlarged contact area with the substrate while maintaining compatibility with reduced integrated circuit dimensions, thereby reducing contact resistance without sacrificing integration level.
2Length of moving object
If the hole dimension is reduced to accommodate smaller integrated circuit dimensions, then the integrated circuit dimension is reduced, but the contact area of the conductive plug is reduced, leading to increased contact resistance
Solution Approach 1:
The contact hole structure utilizes vertical dimensionality by creating a two-segment configuration where the second hole segment extends above the first hole segment. This dimensional approach allows the conductive plug to achieve a larger contact area with the substrate through vertical stacking rather than horizontal expansion, enabling reduced integrated circuit dimensions while maintaining adequate contact area.
Data Source
AI summary
Embodiments provide a contact structure and a fabricating method. The method includes: forming an insulating dielectric layer on a substrate; forming a contact hole penetrating through the insulating dielectric layer, where the contact hole includes a first hole segment and a second hole segment communicating with each other, the first hole segment penetrates to the substrate, the second hole segment is positioned on a side of the first hole segment away from the substrate, the first hole segment has a first orthogonal projection on the substrate, the second hole segment has a second orthogonal projection on the substrate, and the second orthographic projection is positioned in the first orthographic projection; and forming a conductive plug in the contact hole.