Standard Cell Power Layout With Overlapping Buried and Upper Rails
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Solution Overview
Problem
In semiconductor integrated circuit devices using buried power rails, the discontinuity of power lines at relay circuits leads to insufficient power supply, causing unstable circuit operation and reliability issues, and complicates layout design due to the need for different power supply configurations.
Innovation Solution
The implementation of a semiconductor integrated circuit device with first and second standard cells, where the first standard cell receives power from a buried power line and the second standard cell receives power from an upper-layer power line that overlaps the buried power line, allowing for shared basic structure and simplified layout design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a relay circuit is provided in a circuit region where power supply is stopped for reduction in power consumption, then power supply continuity is maintained, but power supply voltage drop increases and layout design becomes difficult
Solution Approach 1:
The patent introduces an upper-layer power line in a different interconnect layer above the buried power rail, allowing the relay circuit to receive power from both the lower-layer buried power rail and the upper-layer power line simultaneously. This multi-layer power supply approach resolves the contradiction by maintaining power continuity without requiring complex single-layer layout modifications.
2Adaptability or versatility
If power lines are made discontinuous at the relay circuit portion, then the relay circuit can be provided in the circuit region, but power supply becomes insufficient and circuit operation becomes unstable
Solution Approach 1:
The patent merges the lower-layer buried power rail and the upper-layer power line to form a combined power supply structure for the relay circuit. Both power lines are connected to the relay circuit simultaneously, ensuring sufficient and stable power supply while allowing the relay circuit to be integrated in the circuit region where power supply is stopped.
3Ease of operation
If different power supply configurations are used for relay circuits and surrounding circuits, then power supply control is achieved, but layout design becomes difficult
Solution Approach 1:
The patent creates a universal power supply structure where the upper-layer power line serves dual purposes: it supplies power to the relay circuit and overlaps with the buried power rail to provide enhanced power delivery. This multi-functional design allows different power supply configurations for power control while maintaining layout simplicity through the regular grid pattern of the upper-layer power line.
Data Source
AI summary
In a semiconductor integrated circuit device using buried power lines, a first standard cell includes a buried power line extending in the X direction to supply VDD1, and a transistor is supplied with VDD1 from the buried power line. A second standard cell includes a buried power line extending in the X direction to supply VDD1 and an upper-layer power line formed in a layer above the buried power line to supply VDD. A transistor of the second standard cell is supplied with VDD from the upper-layer power line. The upper-layer power line overlaps the buried power line in planar view.