3-State Inverter Flip-Flop Layout to Prevent Signal Backflow
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Solution Overview
Problem
The miniaturization of semiconductor processes using Fin-FET technology limits the design of flip-flops, leading to deteriorated characteristics and reduced yield due to inherent process characteristics and the need for sizing technologies that cause taper issues.
Innovation Solution
A Fin-FET-based flip-flop design incorporating a third inverter for signal transfer between the master and slave latches, eliminating the need for sizing technologies and preventing signal backflow, while sharing power and ground contacts to improve layout efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If Fin-FET-based semiconductor process is used for miniaturization, then the size of flip-flop decreases, but design is limited causing deterioration in flip-flop characteristic and decrease in yield
Solution Approach 1:
The flip-flop is divided into separate functional blocks: master latch, slave latch, and a third inverter positioned between them. This segmentation allows each component to be optimized independently, preventing signal backflow between latches while maintaining miniaturization benefits of Fin-FET process
Solution Approach 2:
A third inverter is introduced as an intermediary element between the master latch and slave latch. This intermediary prevents direct signal backflow that would occur in conventional designs, thereby improving yield and characteristics while maintaining the compact Fin-FET structure
2Reliability
If sizing technologies are used to prevent signal backflow, then signal backflow is prevented, but taper issues occur due to inherent process characteristics
Solution Approach 1:
Instead of relying on sizing technologies that cause taper issues, a third inverter is introduced as a structural intermediary. This inverter naturally prevents signal backflow through its inverting function, eliminating the need for problematic sizing adjustments while maintaining manufacturing precision
Solution Approach 2:
The third inverter uses the inversion principle to prevent signal backflow by inverting the signal twice (once in master latch, once in third inverter), ensuring unidirectional signal flow without requiring asymmetric sizing that causes taper issues
3Reliability
If additional transistors are added to prevent signal backflow, then signal backflow is prevented, but the number of transistors increases
Solution Approach 1:
The third inverter serves multiple functions simultaneously: it transfers signals from master to slave latch, prevents signal backflow, and maintains signal integrity. This multi-functionality achieves reliability improvement without proportionally increasing device complexity
Solution Approach 2:
The signal transfer and backflow prevention functions are merged into a single third inverter component, rather than requiring separate components. This consolidation achieves the desired reliability while minimizing the increase in transistor count
4Ease of manufacture
If conventional flip-flop design is used, then layout is simpler, but layout efficiency is reduced due to taper issues and design limitations
Solution Approach 1:
The flip-flop layout is segmented into distinct functional regions (master latch, third inverter, slave latch) that can be systematically arranged. This segmentation improves layout efficiency by reducing interconnections and optimizing signal paths, while maintaining manufacturing simplicity through standardized cell design
Data Source
AI summary
A flip-flop includes an input interface, a first latch, a third inverter, and a second latch. The third inverter and the fifth inverter include first transistors of a first type formed between a first power contact and a second power contact supplied with a power supply voltage on first-type fins, and second transistors of a second type formed between a first ground contact and a second ground contact supplied with a ground voltage on second-type fins.