Backside Contact Layout for FinFET Source/Drain Integration
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Solution Overview
Problem
Integrated circuit devices face challenges in achieving high integration and reliability due to limitations in wiring structures, which affect their capacity and performance as electronic products demand smaller sizes and multi-functionality.
Innovation Solution
The integrated circuit device incorporates a substrate with fin-type active regions, gate lines, nanosheets, and a back side contact structure, including a protruding and substrate-level portion of the back side contact, to enhance integration and reliability by optimizing the layout and electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional wiring structures are used, then device complexity is reduced, but integration capacity and performance are insufficient
Solution Approach 1:
The patent introduces a back side contact structure that extends from the front surface through the substrate to the back surface, utilizing the third dimension (vertical depth) to establish electrical connections. This dimensional transition allows wiring to bypass traditional planar routing constraints, enabling higher integration capacity without proportionally increasing wiring structure complexity.
Solution Approach 2:
The back side contact acts as an intermediary element that facilitates electrical connection between front surface components (source/drain areas) and back surface conductive layers. This intermediary structure resolves the contradiction by providing a direct transmission path that simplifies the overall wiring architecture while enhancing integration capacity.
2Reliability
If wiring structures are optimized for performance, then device reliability improves, but manufacturing complexity increases
Solution Approach 1:
The back side contact structure is formed during the early stages of device fabrication, before final device assembly. The contact holes are etched and filled with conductive material in advance, establishing reliable electrical pathways that simplify subsequent manufacturing steps and reduce overall manufacturing complexity while ensuring device reliability.
3Reliability
If back side contact width is increased for better electrical connection, then electrical conductivity improves, but device area occupancy increases
Solution Approach 1:
The back side contact utilizes the vertical dimension by extending through the substrate thickness, allowing the contact to achieve sufficient electrical connection area in the depth direction rather than requiring excessive width on the planar surface. This dimensional transition improves electrical conductivity without significantly increasing device area occupancy.
Data Source
AI summary
The integrated circuit device includes a substrate, a first fin extending in a first horizontal direction on the substrate, a second fin and a third fin spaced apart from each other in the first horizontal direction and extending in the first horizontal direction, a second source/drain area on the second fin and the third fin, a back side contact between the second fin and the third fin and electrically connected to the second source/drain area, and a back side conductive layer extending in the first horizontal direction and electrically connected to the back side contact. The back side contact includes a first portion protruding from the substrate and a second portion that is coplanar, in a vertical direction, with the substrate. A width of the second portion in the second horizontal direction is greater than a width of the first portion in the second horizontal direction.