Backside Metal Contact Tapering for Scalable Power Rails
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor fabrication methods for backside power rails in integrated circuits face challenges in forming efficient metal contacts on the backside of ICs, which limits further scaling and performance enhancement.
Innovation Solution
A semiconductor structure with backside metal contacts and power rails featuring different taper profiles is formed using a sigma etch process after completing BEOL processes, allowing simultaneous deposition of conductive metals and increasing contact area for improved device performance and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If conventional fabrication methods are used for backside power rails, then manufacturing process is simpler, but contact area between metal contacts and power rails is insufficient
Solution Approach 1:
The patent applies parameter changes by utilizing the sigma etch process to create distinct taper profiles for metal contacts and power rails. The sigma etch process modifies the geometric parameters of the etched features, producing contact holes with one taper profile and power rails with a different taper profile, thereby increasing the contact area between these structures without requiring additional fabrication steps
Solution Approach 2:
The sigma etch process serves multiple functions simultaneously - it creates both the metal contact holes and the power rail structures in a single self-contained process step. The process automatically generates the appropriate taper profiles for both structures, eliminating the need for separate formation steps and reducing overall fabrication complexity while maximizing contact area
2Productivity
If backside power rails are implemented to enable scaling, then device scaling is improved, but forming efficient metal contacts becomes more difficult
Solution Approach 1:
The sigma etch process changes the geometric parameters of the etched features to create optimized taper profiles that facilitate efficient metal contact formation. By controlling the etch chemistry and process parameters, the patent achieves favorable contact hole geometries that improve metal fill efficiency and contact reliability, thereby enabling continued device scaling
Solution Approach 2:
The sigma etch process acts as an intermediary that bridges the gap between backside power rail implementation and efficient metal contact formation. This single process step simultaneously creates the necessary contact holes and power rail structures with appropriate geometries, simplifying the overall manufacturing process while enabling advanced scaling
Data Source
AI summary
A semiconductor structure with improved backside metal contacts includes a plurality of source/drain regions within a field effect transistor. A backside metal contact is electrically connected to at least one source/drain region of the plurality of source/drain regions. The backside metal contact includes a first taper profile. The semiconductor structure further includes a backside power rail electrically connected to the at least one source/drain region through the backside metal contact. The backside power rail includes a second taper profile that is different from the first taper profile.