Filler Cells Optimize SRAM and Standard Cell Layout
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Solution Overview
Problem
Conventional integrated circuits face inefficiencies in chip area usage due to the need for large white spaces between Static Random Access Memory (SRAM) cells and standard cells, which are not cost-effective in terms of space optimization.
Innovation Solution
The introduction of filler cells with varying heights, strategically placed between SRAM arrays and standard cells, to minimize spacing without violating design rules, allowing for optimal alignment and efficient use of chip area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If white space is reserved between SRAM cells and standard cells to comply with design rules, then design rule compliance is maintained, but chip area usage efficiency deteriorates
Solution Approach 1:
The patent introduces filler cells as intermediary elements between SRAM cells and standard cells. These filler cells serve as mediators that satisfy design rule requirements for spacing while enabling tighter overall integration. The filler cells occupy the necessary white space but are designed to be functionally integrated or minimally intrusive, thus resolving the contradiction between maintaining design rule compliance and improving chip area usage efficiency.
2Manufacturing precision
If large white space is reserved between SRAM cells and standard cells, then design rule compliance is maintained, but space utilization deteriorates
Solution Approach 1:
Filler cells are introduced as intermediary elements that satisfy design rule spacing requirements while minimizing impact on overall space utilization. These filler cells act as buffers that enable closer integration of SRAM and standard cell regions without violating manufacturing constraints, thus improving productivity in terms of effective space utilization.
Solution Approach 2:
The patent employs parameter changes by varying the dimensions, positioning, and electrical characteristics of filler cells to optimize space utilization. By adjusting parameters such as filler cell size, orientation, and connectivity, the design achieves better space utilization while maintaining design rule compliance, thereby improving overall productivity.
Data Source
AI summary
A method includes laying out a standard cell region, with a rectangular space being within the standard cell region. The standard cell region includes a first row of standard cells having a first bottom boundary facing the rectangular space, and a plurality of standard cells having side boundaries facing the rectangular space. The plurality of standard cells include a bottom row of standard cells. A memory array is laid out in the rectangular space, and a second bottom boundary of the bottom row and a third bottom boundary of the memory array are aligned to a same straight line. A filler cell region is laid out in the rectangular space. The filler cell region includes a first top boundary contacting the first bottom boundary of the first row of standard cells, and a fourth bottom boundary contacting a second top boundary of the memory array.