Flash Memory Control Gate Strap Layout for Efficient Contacts
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Solution Overview
Problem
There is a need for improved structures and methods in flash memory cell arrays to enhance the efficiency and reliability of data storage and retrieval, particularly in non-volatile memory devices like flash memory, which often face challenges in maintaining data integrity and reducing manufacturing complexities.
Innovation Solution
The proposed structure for a flash memory cell array includes a first and second control gate with asymmetrical gate strap regions, projections, and contacts, along with a semiconductor substrate, floating gates, and dielectric layers, facilitating efficient contact formation and data storage through asymmetrical gate strap regions and projections, enhancing manufacturing efficiency and data retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If asymmetrical gate strap regions with projections are added to control gates, then contact formation efficiency is improved, but device complexity increases
Solution Approach 1:
The patent applies asymmetry by creating gate strap regions with projections that extend outwardly from only one sidewall of each control gate, rather than symmetrically from both sidewalls. This asymmetric design enables more efficient contact formation processes while maintaining manufacturability through standardized fabrication techniques.
Solution Approach 2:
The gate strap region is segmented into distinct portions: a first portion with the protruding projection and a second portion without the projection. This segmentation allows for optimized contact formation in the first portion while maintaining structural integrity and electrical functionality in the second portion.
2Manufacturing precision
If uniform spacing gaps between control gates are maintained, then manufacturing precision is improved, but flexibility in gate strap region design is reduced
Solution Approach 1:
The patent applies local quality by maintaining uniform spacing gaps between the second sidewalls of adjacent control gates for manufacturing precision, while simultaneously allowing the gate strap regions to have asymmetric projections extending from only one sidewall. This creates different structural qualities in different locations: uniform spacing for fabrication control and asymmetric projections for contact formation efficiency.
Data Source
Figure 1
Figure 2~2A
Figure 2B~2C
AI summary
Structures for a flash memory cell array and methods of forming a structure for a flash memory cell array. The structure comprises a first gate stack including a first control gate and a second gate stack including a second control gate. The first control gate has a first sidewall, a second sidewall opposite from the first sidewall, and a gate strap region, and the gate strap region includes a projection extending outwardly from the first sidewall of the first control gate. The second control gate has a first sidewall and a second sidewall opposite from the first sidewall, and the second sidewall of the second control gate faces the second sidewall of the first control gate.