205
7
Technology CAD of StrainEngineered MOSFETs
Technology computer-aided design (TCAD) refers to the use of computer
simulation to model semiconductor processing and device operation. TCAD
provides insight into the fundamental physical phenomena that ultimately
impact performance and yield. Process variability is becoming more and
more design for manufacturing challenges for designers as new process
steps are added for advanced technology nodes. By integrating TCADderived models with physical design tools, the designer can focus on optimising variation awareness for increased performance, productivity, and
predictability. From the 90 nm node onward, issues with manufacturability
and yield have forced the electronic design automation (EDA) industry and
manufacturing to move closer together. In particular, process and device
information that affect functionality and yield need to be incorporated into
the design flow, addressing more comprehensively issues of design for manufacturing (DFM) and yield (DFY). For true DFM and DFY, it is necessary
to include process variability in the design process. From the 65 nm node,
the variability has increased significantly further as a result of feature scaling and the introduction of new materials and innovative techniques such
as strain engineering. The information needed by designers includes layout
sensitivity as well as the effect of process variability on the electrical characteristics of devices and interconnects.
The strength of TCAD lies in the accurate prediction of device and interconnects variability due to layout as well as random variations in the process. Variability information can then be incorporated into the design tools
through appropriate statistical compact models. Ultimately, this will lead
to an improved design flow that addresses manufacturability issues in a
comprehensive way. Beyond traditional process/device modelling and optimisation TCAD provides unique advantages in manufacturing. In a manufacturing for design approach, TCAD can be used for global advanced
process control, helping the manufacturing engineer optimise parametric
product yield for specific designs without having to understand the details
of the design itself.
7
Technology CAD of StrainEngineered MOSFETs
Technology computer-aided design (TCAD) refers to the use of computer
simulation to model semiconductor processing and device operation. TCAD
provides insight into the fundamental physical phenomena that ultimately
impact performance and yield. Process variability is becoming more and
more design for manufacturing challenges for designers as new process
steps are added for advanced technology nodes. By integrating TCADderived models with physical design tools, the designer can focus on optimising variation awareness for increased performance, productivity, and
predictability. From the 90 nm node onward, issues with manufacturability
and yield have forced the electronic design automation (EDA) industry and
manufacturing to move closer together. In particular, process and device
information that affect functionality and yield need to be incorporated into
the design flow, addressing more comprehensively issues of design for manufacturing (DFM) and yield (DFY). For true DFM and DFY, it is necessary
to include process variability in the design process. From the 65 nm node,
the variability has increased significantly further as a result of feature scaling and the introduction of new materials and innovative techniques such
as strain engineering. The information needed by designers includes layout
sensitivity as well as the effect of process variability on the electrical characteristics of devices and interconnects.
The strength of TCAD lies in the accurate prediction of device and interconnects variability due to layout as well as random variations in the process. Variability information can then be incorporated into the design tools
through appropriate statistical compact models. Ultimately, this will lead
to an improved design flow that addresses manufacturability issues in a
comprehensive way. Beyond traditional process/device modelling and optimisation TCAD provides unique advantages in manufacturing. In a manufacturing for design approach, TCAD can be used for global advanced
process control, helping the manufacturing engineer optimise parametric
product yield for specific designs without having to understand the details
of the design itself.