Memory Array Dummy Word Line Shielding Plug
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The presence of a dummy word line adjacent to functional word lines in memory devices leads to performance differentiation and coupling effects, resulting in uneven memory cell performance and leakage issues during program and read operations.
Innovation Solution
A memory device structure is designed with a dummy word line adjacent to the outermost word line, where a shielding plug is placed between them, enlarging the space and using a metal shielding to isolate the functional word line from voltage coupling, thus reducing coupling effects and eliminating leakage by omitting self-aligned source regions around the dummy word line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a dummy word line is disposed directly adjacent to functional word lines to increase lithography exposure uniformity, then lithography exposure uniformity is improved, but coupling effect occurs between the dummy word line and nearest functional word line causing performance differentiation
Solution Approach 1:
The dummy word line structure is segmented into two parts: the dummy word line itself and an isolated conductive structure separated by an insulating layer. This segmentation prevents direct electrical coupling between the dummy word line and functional word lines while maintaining the lithography exposure uniformity benefit.
Solution Approach 2:
An insulating layer is introduced as an intermediary between the dummy word line and the nearest functional word line. This intermediary prevents direct electrical coupling and eliminates the performance differentiation issue while allowing both structures to coexist for lithography uniformity.
2Illumination intensity
If a dummy word line is disposed directly adjacent to functional word lines, then lithography exposure uniformity is improved, but leakage occurs during program and read operations
Solution Approach 1:
The structure is segmented with an insulating layer separating the dummy word line from functional word lines, preventing direct electrical connection. This eliminates leakage paths during program and read operations while preserving the lithography exposure uniformity advantage.
Solution Approach 2:
The insulating layer acts as an intermediary that blocks electrical leakage between the dummy word line and functional word lines during program and read operations, while allowing both structures to remain adjacent for lithography uniformity.
3Ease of manufacture
If self-aligned source regions are formed around dummy word line, then manufacturing process is simplified, but coupling effect and leakage problems are exacerbated
Solution Approach 1:
Self-aligned source regions are extracted/removed from around the dummy word line. This eliminates the coupling effect and leakage problems that would result from having source regions adjacent to the dummy word line, while the dummy word line remains for lithography uniformity.
Solution Approach 2:
The insulating layer serves as an intermediary that prevents electrical coupling between the dummy word line and nearby structures, allowing the dummy word line to be present without creating harmful coupling effects or leakage paths.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration tightens the erase threshold voltage distribution of memory cells, enhances programming ability, and enlarges the read judgment window by minimizing coupling effects and leakage, ensuring equivalent performance across all word lines.
Implementation Method 1
the shielding plug can be a metal shielding to isolate the nearest functional word line from being voltage coupling with the dummy word line
Data Source
AI summary
A memory array including a plurality of memory cells, a plurality of word lines, a dummy word line, and a plug is provided. Each word line is coupled to corresponding memory cells. A dummy word line is directly adjacent to an outmost word line of the plurality of word lines. The plug is located between the dummy word line and the outmost word line.