Interdigitated Memory Cell Array Layout for Shrinking
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Solution Overview
Problem
Conventional SRAM memory cell arrays face limitations in shrinking due to fixed spacing distances and optical limitations, leading to design rule check violations and inferior implantation results, hindering further integration and size reduction.
Innovation Solution
A layout configuration featuring interdigitated comb-like and fishbone-shaped doped regions of complementary conductivity types, allowing memory cells and strap cells to be formed without spacing distances, enabling continuous configurations for improved size reduction and implantation results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional islanding configurations of doped regions are used, then manufacturing compliance with TLR is maintained, but memory cell array size cannot be reduced
Solution Approach 1:
The patent merges adjacent doped regions of the same conductivity type into continuous regions, eliminating the need for spacing between separate regions. This combining approach reduces the overall memory cell array area while maintaining TLR compliance, as the continuous regions satisfy topological layout rules without requiring gaps between discrete islands.
Solution Approach 2:
The patent transitions from one-dimensional linear arrangements of doped regions to two-dimensional interdigitated comb-like and fishbone-shaped configurations. This dimensional change allows regions to be interlocked without overlapping, achieving compact packing that reduces area while maintaining manufacturing compliance through proper spatial arrangement.
2Area of stationary object
If spacing distances between doped regions are reduced, then memory cell array size can be reduced, but TLR violations occur and implantation quality deteriorates
Solution Approach 1:
By merging adjacent doped regions into continuous regions, the patent eliminates spacing gaps entirely rather than merely reducing them. This approach maintains implantation quality by providing uniform continuous regions for ion implantation while achieving area reduction, avoiding the TLR violations that would occur with reduced spacing between discrete regions.
3Area of stationary object
If optical limitations are overcome to reduce doped region size, then memory cell array can be shrunk, but implantation results become inferior
Solution Approach 1:
The patent uses two-dimensional interdigitated comb-like and fishbone-shaped configurations that maintain adequate implantation widths while achieving compact overall array size. The extended perimeter and optimized geometry of these shapes provide sufficient area for quality ion implantation without requiring larger optical processing margins, enabling array shrinkage without sacrificing implantation results.
Data Source
AI summary
A layout configuration for a memory cell array includes at least a comb-like doped region having a first conductivity type and a fishbone-shaped doped region having a second conductivity type. The second conductivity type and the first conductivity type are complementary. Furthermore, the comb-like doped region and the fishbone-shaped doped region are interdigitated.