Staggered SRAM Cell Array Layout for Area and Yield Optimization
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Solution Overview
Problem
Existing IC designs face challenges in achieving high density and good product yield rate simultaneously due to design rules that limit the reduction of memory cell array size and yield rate.
Innovation Solution
A staggered SRAM cell array design where the memory cell areas are shifted to create overlapping boundaries, allowing for reduction or increase in peripheral areas while keeping the latch areas constant, thus adjusting the total area and yield rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If memory cell areas are arranged in a conventional grid pattern following design rules, then manufacturing precision and design rule compliance are maintained, but the total area cannot be reduced and yield rate is limited
Solution Approach 1:
The patent applies asymmetry by shifting the second memory cell area relative to the first memory cell area, creating a staggered configuration where corresponding edges do not align. This asymmetric arrangement reduces the total peripheral area while maintaining latch area integrity and design rule compliance, directly resolving the contradiction between area reduction and manufacturing precision.
Solution Approach 2:
The invention transitions from a conventional two-dimensional grid alignment to a staggered arrangement that effectively utilizes space in a different dimensional configuration. By offsetting memory cell areas in the horizontal direction while maintaining vertical alignment, the design creates overlapping peripheral regions that can be shared, reducing total area without compromising manufacturing precision.
2Quantity of substance
If memory cell array size is reduced to increase density, then component density improves, but product yield rate decreases
Solution Approach 1:
The patent merges the peripheral areas of adjacent memory cell areas by creating a staggered configuration where the first and second memory cell areas overlap in the horizontal direction. This merging allows shared peripheral structures between adjacent cells, increasing component density while maintaining sufficient spacing and design rule compliance to preserve product yield rate.
3Adaptability or versatility
If conventional memory cell arrangement is used, then design rule compliance is ensured, but flexibility in adjusting area and yield rate is limited
Solution Approach 1:
The staggered configuration introduces controlled asymmetry in the layout where the second memory cell area is horizontally offset from the first. This asymmetric design provides flexibility in adjusting the total area and yield rate by modifying the shift distance, while maintaining regularity in the latch area structures to avoid excessive layout complexity.
Data Source
AI summary
A memory device includes a first memory cell area having a first latch area where one or more electronic components are constructed for storing a value, and a first peripheral area surrounding the first latch area; and a second memory cell area being disposed adjacent to a first side of the first memory cell area, and having a second latch area where one or more electronic components are constructed for storing a value, and a second peripheral area surrounding the second latch area. One edge of the first memory cell area shifts away from its corresponding edge of the second memory cell area. Thus, the area or yield rate of the memory device can be adjusted.