SRAM Fin Uniformity via Dummy Fin Copying
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Solution Overview
Problem
In semiconductor devices using fin type transistors, the absence of a dummy fin between adjacent SRAM cells leads to non-uniform fin shapes and thicknesses, potentially causing electrical characteristics deterioration due to the formation of non-disposition regions, which can result in the short channel effect.
Innovation Solution
Incorporating a dummy fin made of the same material as the device regions, positioned between the outermost device regions of adjacent SRAM cells, which maintains uniform fin spacing and prevents non-uniformity, thereby ensuring consistent electrical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If no dummy fin is formed between adjacent SRAM cells, then device complexity is reduced and manufacturing is simpler, but fin shape uniformity deteriorates and short channel effect occurs
Solution Approach 1:
A dummy fin is formed as a copy of the actual fin structure between adjacent SRAM cells. This dummy fin replicates the geometric and material characteristics of real fins, ensuring that etching and fabrication processes produce uniform fin shapes across the entire substrate, thereby preventing short channel effect while maintaining manufacturing simplicity
Solution Approach 2:
The dummy fin is constructed with the same material composition and geometric dimensions as the actual fins, creating a homogeneous structure throughout the semiconductor substrate. This homogeneity ensures consistent electrical characteristics and uniform fin formation during manufacturing, eliminating the need for complex differentiated structures
2Manufacturing precision
If dummy fin is formed between adjacent SRAM cells, then fin shape uniformity is improved and short channel effect is suppressed, but device complexity increases
Solution Approach 1:
The dummy fin is created as an identical copy of the actual fin structure, using the same materials and dimensions. This copying approach ensures uniform fin formation without requiring complex differentiated structures, as the dummy fin simply replicates the proven successful fin geometry
Solution Approach 2:
By making the dummy fin homogeneous with the actual fins in terms of material composition and geometric structure, the patent avoids introducing structural complexity. The uniformity in material and shape simplifies the manufacturing process while ensuring consistent electrical characteristics across all fin structures
Data Source
AI summary
A semiconductor device according to an embodiment of the invention includes: a semiconductor substrate; device regions formed on the semiconductor substrate, the device regions having a length direction in a predetermined direction; a plurality of transistors having gate electrodes, respectively, the gate electrodes extending in a direction approximately perpendicular to the predetermined direction, the plurality of transistors having a source/drain region and a channel region having a channel direction approximately parallel to the predetermined direction in the device region; a plurality of SRAM cells disposed in an array, each of the plurality of SRAM cells including the plurality of transistors; and a dummy region made of the substantially same material as that of the device regions, the dummy region being formed between the outermost device regions of the SRAM cells adjacent to each other in the direction approximately perpendicular to the predetermined direction, the dummy region having a length direction approximately parallel to the predetermined direction.