Grounding Dummy Gate via Extended Stacked Contact
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Solution Overview
Problem
As integrated circuits become more complex, connecting devices through interconnect layers becomes increasingly challenging due to smaller device geometries, leading to difficulties in grounding dummy gates without shorting or requiring additional layout space.
Innovation Solution
A semiconductor device and method that involve forming a dummy gate with adjacent active contacts, a dielectric layer, and extended stacked contacts to electrically ground the dummy gate, while maintaining electrical isolation from neighboring contacts, allowing for scalable design-rule spacing and preventing shorting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If traditional separate gate contact and stacked contact structures are used, then electrical connection to dummy gate and active contacts is achieved, but layout area increases and design rule scalability is limited
Solution Approach 1:
The patent merges the gate contact and stacked contact into a single extended stacked contact structure. This contact extends from the active contact region through the dielectric layer and makes electrical connection to the dummy gate, eliminating the need for separate gate contact and stacked contact structures. The merged structure reduces layout area while maintaining reliable electrical connections to both the active contact and dummy gate.
Solution Approach 2:
The extended stacked contact performs multiple functions simultaneously: it serves as the stacked contact for the active contact, provides electrical connection to the dummy gate, and acts as the gate contact. This multi-functional design eliminates redundant structures and improves design rule scalability by reducing the number of distinct contact elements that must be spaced and aligned.
2Reliability
If extended stacked contact overlaps both dummy gate and active contact, then electrical grounding is achieved, but risk of shorting increases
Solution Approach 1:
The extended stacked contact uses the dielectric layer as an intermediary medium. The contact passes through the dielectric layer which provides electrical isolation, allowing the contact to extend from the active contact region to the dummy gate while maintaining proper electrical connections. The dielectric layer acts as a mediator that enables the extended contact structure to achieve grounding functionality while preventing unwanted shorting through its insulating properties.
3Reliability
If additional layout space is allocated for grounding dummy gate, then shorting is prevented, but device complexity and manufacturing steps increase
Solution Approach 1:
The patent combines the grounding function with the existing stacked contact structure. The extended stacked contact that already provides connection to the active contact is extended to also provide connection to the dummy gate, merging two functions into one structure. This eliminates the need for additional separate grounding contacts and reduces manufacturing complexity by reducing the number of patterning and etching steps required.
Data Source
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AI summary
A semiconductor device includes a gate (210) and a first active contact (220) adjacent to the gate. Such a device further includes a first stacked contact (1310) electrically coupled to the first active contact, including a first isolation layer (1200) on sidewalls electrically isolating the first stacked contact from the gate. The device also includes a first via (2000) electrically coupled to the gate and landing on the first stacked contact. The first via electrically couples the first stacked contact and the first active contact to the gate to ground the gate.