Backside Contact Layout With Spacer Isolation Against Gate Shorts
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Solution Overview
Problem
The risk of backside contact to gate short is a significant challenge in integrated circuit fabrication, particularly with the increasing number of transistors produced, which can lead to connectivity issues and device failure.
Innovation Solution
The implementation of a backside contact structure that includes a backside protective spacer, separated from the gate region by a bottom dielectric isolation layer, to prevent direct contact and ensure reliable connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a backside contact is implemented to improve connectivity, then the electrical connection to the epitaxial region is enhanced, but the risk of contact to gate short increases
Solution Approach 1:
The patent introduces a bottom dielectric isolation layer as an intermediary between the backside contact and the gate region. This dielectric layer acts as a mediator that allows the backside contact to maintain electrical connection to the epitaxial region while preventing direct contact with the gate, thereby eliminating the short circuit risk.
Solution Approach 2:
The patent segments the space between the backside contact and gate region into distinct functional layers: the bottom dielectric isolation layer provides electrical isolation, while the backside protective spacer provides physical separation. This segmentation allows independent optimization of connectivity and protection functions.
2Reliability
If additional protective structures are added to prevent contact to gate short, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The bottom dielectric isolation layer serves multiple functions simultaneously: it provides electrical isolation between the backside contact and gate region, acts as a structural support layer, and defines the boundary for spacer formation. This multi-functionality reduces the need for additional separate protective structures.
Solution Approach 2:
The backside protective spacer is formed in advance during the fabrication process, extending from the bottom dielectric isolation layer to provide pre-positioned protection. This preliminary action ensures that the protective structure is already in place before subsequent processing steps, preventing contact to gate short from the outset.
Data Source
AI summary
Embodiments of the invention include a transistor comprising a gate region and an epitaxial region, the transistor comprising a frontside opposite a backside. A backside contact is coupled to the epitaxial region and separated from the gate region by a bottom dielectric isolation layer and a backside protective spacer