Resistor in Single Diffusion Break for FinFET Isolation
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Solution Overview
Problem
The formation of resistors in middle-of-line (MOL) and back-end-of-line (BEOL) layers in integrated circuits (ICs) adds complexity and reduces yield, as well as increases layer thickness, due to the need for multiple processing steps and masking, and blocks the use of transistors that would otherwise be usable.
Innovation Solution
A resistor is positioned within a single diffusion break (SDB) in a semiconductor fin, allowing its formation in the front-end-of-line (FEOL) layers, which simplifies the process, reduces the need for additional mask steps, and enables precise critical dimension control and resistance selection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If resistors are formed in MOL or BEOL layers, then resistors can be integrated into the IC, but the process complexity increases and yield decreases
Solution Approach 1:
The patent merges resistor formation with the SDB structure formation process. The resistor material is deposited and patterned simultaneously with the diffusion break isolation structure, eliminating separate resistor fabrication steps. This combining of operations reduces process complexity while maintaining resistor integration capability
Solution Approach 2:
The SDB structure serves dual functions: it provides diffusion break isolation between adjacent finFETs and simultaneously hosts the resistor element. This multi-functionality eliminates the need for dedicated resistor formation processes in MOL/BEOL layers, reducing overall process complexity while achieving resistor integration
2Adaptability or versatility
If resistors are formed in MOL or BEOL layers, then resistors can be integrated into the IC, but the number of processing steps increases
Solution Approach 1:
The resistor material is deposited and patterned during the FEOL process stage, before the MOL/BEOL layers are formed. This preliminary action allows the resistor structure to be established early in the fabrication sequence, eliminating the need for additional resistor-specific processing steps in later MOL/BEOL stages
3Adaptability or versatility
If resistors are formed in MOL or BEOL layers, then resistors can be integrated into the IC, but layer thickness increases
Solution Approach 1:
The patent transitions resistor placement from the traditional planar MOL/BEOL layers to a vertical integration within the SDB structure. The resistor is formed within the depth of the diffusion break region, utilizing the vertical dimension rather than adding horizontal layer thickness. This dimensional shift maintains overall IC thickness while achieving resistor integration
4Adaptability or versatility
If resistors are formed in MOL or BEOL layers, then resistors can be integrated into the IC, but transistors that would otherwise be usable are blocked
Solution Approach 1:
The patent extracts the resistor element from the MOL/BEOL layer space and relocates it to the SDB region. This extraction frees up the MOL/BEOL layers for their primary interconnect functions and allows transistors to be positioned and utilized without being blocked by resistor structures, thereby improving transistor utilization while maintaining resistor integration
Data Source
AI summary
A resistor for an integrated circuit (IC), an IC and a related method are disclosed. The resistor may include a metal alloy resistor body positioned within a single diffusion break (SDB). The SDB provides an isolation region in a semiconductor fin between a pair of fin-type field effect transistors (finFETs). The resistor in the SDB allows for the resistor to be built at front-end-of-line (FEOL) layers, which saves on space and expense, and allows for precise dimensions for the resistor.