Semiconductor Metal Wiring Slit Design for Contact Resistance
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Solution Overview
Problem
In semiconductor devices with metal wiring formed by the damascene process, securing a stable contact area between metal wiring and contact plugs is challenging, leading to increased contact resistance and deteriorated operating characteristics due to taper angles and separation part dimensions.
Innovation Solution
A semiconductor device design featuring a contact plug at the end of the metal wiring with a slit formed apart from the contact plug, where the slit's distance from the metal wiring edge is equal to or greater than twice the contact plug's diameter, reducing taper angles and enhancing contact area stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the contact plug is positioned at the end of the metal wiring in conventional damascene process, then the wiring layout flexibility is improved, but the contact area between metal wiring and contact plug is reduced leading to increased contact resistance
Solution Approach 1:
The metal wiring is segmented by introducing a slit that divides the wiring into multiple sections. This segmentation allows the contact plug to be positioned at the end while maintaining adequate contact area, as the slit creates distinct zones that ensure proper electrical connection without compromising layout flexibility.
Solution Approach 2:
The slit is positioned at a specific distance from the contact plug (equal to or larger than twice the contact plug diameter) to create a local structural modification. This local quality change ensures that the contact area is maintained where needed while allowing the wiring to extend to the contact plug position, thus resolving the contradiction between layout flexibility and contact resistance.
2Productivity
If the metal wiring width is reduced to achieve finer pitch, then the integration density is improved, but the contact area at the wiring end is further reduced exacerbating contact resistance
Solution Approach 1:
By segmenting the narrow metal wiring with a slit, the patent ensures that even though the overall wiring width is reduced for higher integration density, the contact area at the end is preserved. The slit creates a structured division that maintains electrical connection quality despite the reduced wiring dimensions.
Solution Approach 2:
The patent introduces a specific parameter for the slit position (distance from contact plug equal to or larger than twice the contact plug diameter) to optimize the balance between wiring width for integration density and contact area for reliability. This parameter change allows fine-tuning of the structure to achieve both goals.
3Ease of manufacture
If the distance between wiring edge and slit is too small, then the manufacturing process is simplified, but the contact area stability is reduced leading to increased parasitic resistance
Solution Approach 1:
The patent establishes a specific parameter range for the distance between wiring edge and slit (equal to or larger than twice the contact plug diameter) that optimizes both manufacturing feasibility and contact area stability. This parameter specification ensures adequate contact area while maintaining reasonable manufacturing complexity.
Data Source
AI summary
An object of the present invention is to improve the operating characteristics of a semiconductor device.A semiconductor device has a contact plug that is formed over a semiconductor substrate, a metal wiring that is coupled to the upper surface of the contact plug, and a slit that is formed in the metal wiring. Further, the contact plug is formed at an end of the metal wiring, and the slit is formed at a position apart from the contact plug in an X direction in a planar view. A distance between an edge of the upper surface at the end of the metal wiring and the upper surface of the slit in the X direction is equal to or larger than and twice or smaller than a first plug diameter of the upper surface of the contact plug in the X direction.