Non-Volatile Memory Contact Layout via Strip Isolation
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Solution Overview
Problem
Conventional non-volatile memory manufacturing processes are complex and costly due to the need for H-shaped active regions and extensive optical proximity correction, which increases chip area and hinders miniaturization.
Innovation Solution
A manufacturing method that connects source/drain regions of adjacent active regions using contacts extending across isolation structures, reducing chip area occupancy and simplifying the process by forming strip-shaped isolation structures and using self-alignment techniques for contact formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If H-shaped active regions are formed to avoid shortage and misalignment, then manufacturing reliability is improved, but chip area increases and manufacturing complexity increases
Solution Approach 1:
The active region is divided into two separate strip-shaped regions instead of forming a continuous H-shaped region. This segmentation allows each strip to be independently formed and aligned, eliminating the need for complex optical proximity correction while reducing the total chip area occupied by active regions.
Solution Approach 2:
Contacts are extended in the first direction (length direction of active regions) to span across isolation structures and connect source/drain regions of adjacent active regions. This dimensional change in contact orientation allows connection without requiring additional active region area, thereby reducing chip area while maintaining reliability.
2Manufacturing precision
If H-shaped active regions are formed with optical proximity correction, then manufacturing precision is improved, but manufacturing time increases
Solution Approach 1:
The active region pattern is segmented into two separate strips rather than forming a complex H-shape. This simplification of the photolithography pattern eliminates the need for extensive optical proximity correction calculations and processing, significantly reducing manufacturing time while maintaining alignment precision through simpler geometry.
3Reliability
If H-shaped active regions are formed, then contact alignment reliability is improved, but device complexity increases
Solution Approach 1:
The active region is segmented into two simple strip shapes rather than one complex H-shape. This segmentation simplifies the overall device structure while maintaining alignment reliability through the use of extended contacts that span across isolation structures to connect the segmented regions.
Solution Approach 2:
Contacts are extended in the first direction (parallel to active region length) rather than only in the second direction (perpendicular to active region length). This dimensional change simplifies the structural arrangement by allowing contacts to bridge across isolation structures without requiring complex H-shaped active regions, thereby reducing device complexity while maintaining alignment reliability.
Data Source
AI summary
In a manufacturing method of a non-volatile memory, a substrate is provided, and strip-shaped isolation structures are formed in the substrate. A first memory array including memory cell columns is formed on the substrate. Each memory cell column includes memory cells connected in series with one another, a source/drain region disposed in the substrate outside the memory cells, select transistors disposed between the source/drain region and the memory cells, control gate lines extending across the memory cell columns and in a second direction, and first select gate lines respectively connecting the select transistors in the second direction in series. First contacts are formed on the substrate at a side of the first memory array and arranged along the second direction. Each first contact connects the source/drain regions in every two adjacent active regions.