Backside Contact Extension Region for Lower-Resistance BEOL Wiring
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Solution Overview
Problem
The manufacturing of backside back-end-of-line (BEOL) networks in semiconductor IC devices is challenging due to difficulties in providing adequate electrical isolation between adjacent backside contacts and backside wires, leading to issues such as increased interfacial resistance and alignment complexities.
Innovation Solution
The implementation of backside contacts with extension regions, which provide an increased surface area for backside wires to connect, thereby reducing interfacial resistance and easing alignment complexities, while also allowing for increased backside wire pitch to reduce the propensity of shorting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If backside contacts are made larger to reduce interfacial resistance, then connection reliability improves, but alignment complexities increase
Solution Approach 1:
The contact structure extends in the lateral dimension through extension regions that protrude from the inline region. This dimensional extension increases the effective surface area for wire connection without requiring larger vertical dimensions, thereby reducing interfacial resistance while maintaining alignment feasibility through the structured geometry.
Solution Approach 2:
Different regions of the backside contact have different functions: the inline region provides direct electrical connection beneath the source/drain region, while the extension regions provide additional connection surface area that protrudes laterally. This local differentiation optimizes both connection reliability and alignment characteristics.
2Reliability
If backside wire pitch is increased to reduce shorting propensity, then reliability improves, but routing density decreases
Solution Approach 1:
The backside contact structure is segmented into an inline region and laterally protruding extension regions. This segmentation allows wires to connect to the extension regions with greater alignment tolerance, enabling reduced wire pitch while maintaining connection reliability and reducing shorting propensity through the increased effective connection area.
Data Source
AI summary
A backside contact includes an extension region and may further include an inline region. The inline region is below a source/drain region may the extension region extends horizontally generally underneath an adjacent source/drain region. The adjacent S/D region may be connected to a frontside back end of line (BEOL) network by a frontside contact. The extension region may provide for relatively increased surface area for a backside wire of a backside BEOL network to connect thereto, which may relatively decrease the interfacial resistance therebetween and which may ease alignment and/or landing complexities of the backside wire against the backside contact. The extension region may further allow for relatively increased backside wire pitch between backside wires of the backside BEOL network, which may reduce the propensity of shorting between the backside wires.