Dielectric Fill Fin Structure for FinFET Gate Cut Reliability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The semiconductor industry faces challenges in maintaining device reliability due to inter-layer dielectric (ILD) layer loss and work function metal damage during the metal gate cut process in FinFET fabrication, which affects gate control and threshold voltage stability.
Innovation Solution
The introduction of fill fins, which are additional fins inserted between device fins to improve fin density and provide structural support, electrical isolation, and gate interconnect features, thereby mitigating ILD layer loss and work function metal damage by distributing the gate stack uniformly and preventing metal pulling into ILD or shallow trench isolation features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal gate cut process is performed in FinFET fabrication, then gate control is improved, but inter-layer dielectric layer loss and work function metal damage occur
Solution Approach 1:
The patent applies preliminary action by forming a protective dielectric layer over the inter-layer dielectric before the metal gate cut process. This protective layer is deposited in advance to prevent damage during subsequent processing steps, specifically preventing ILD layer loss and work function metal damage while allowing the metal gate cut to proceed for improved gate control
2Reliability
If metal gate cut process is performed in FinFET fabrication, then gate control is improved, but work function metal damage occurs
Solution Approach 1:
The patent applies preliminary action by forming a protective dielectric layer over the work function metal layer before the metal gate cut process. This protective layer is deposited in advance to prevent damage during subsequent processing steps, specifically preventing work function metal damage while allowing the metal gate cut to proceed for improved gate control
3Reliability
If fin density is increased, then gate control is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the gate structure into multiple segments corresponding to individual fins. Each fin has its own gate electrode and dielectric layer, allowing independent control and optimization. This segmentation enables improved gate control through increased fin density while managing device complexity through modular structure design
Data Source
AI summary
A semiconductor device includes a substrate and a semiconductor structure over the substrate. The semiconductor device also includes a first dielectric structure over the substrate, and the first dielectric structure has a first height. The semiconductor device further includes a second dielectric structure over the substrate, and the second dielectric structure has a second height. The second height is smaller than the first height. In addition, the semiconductor device includes a first gate stack wrapped around the first dielectric structure, and the semiconductor structure and the second dielectric structure are spaced apart from the first gate stack. The semiconductor device includes a second gate stack wrapped around the second dielectric structure and the semiconductor structure, and the second gate stack is electrically isolated from the first gate stack.