3D Memory Word Line Segmentation for Dense Array Stability
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Solution Overview
Problem
Existing semiconductor memory technologies face challenges in achieving high memory cell density while preventing structural instability due to high aspect ratios during the formation of word lines and bit lines, leading to issues such as twisting or collapsing of features.
Innovation Solution
A multiple-patterning process is employed to form word lines and transistors in a semiconductor memory array, involving two separate patterning steps to reduce the aspect ratio and prevent structural instability, allowing for improved memory cell density and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single patterning process is used to form word lines and bit lines, then the manufacturing process is simpler, but the aspect ratio becomes too high causing structural instability and twisting or collapsing of features
Solution Approach 1:
The patterning process is divided into multiple separate patterning steps instead of attempting to form all word lines and bit lines in a single step. This segmentation allows each patterning operation to work with lower aspect ratios, preventing structural collapse while maintaining manufacturing feasibility through systematic multi-step processing
2Quantity of substance
If memory cell density is increased, then more data can be stored, but the aspect ratio of features increases leading to twisting or collapsing during formation
Solution Approach 1:
By dividing the patterning into multiple steps, each step can achieve higher local density without creating excessively high aspect ratios that would cause structural failure. The segmented approach allows dense packing of memory cells while maintaining structural integrity through controlled, sequential feature formation
Solution Approach 2:
The patent employs three-dimensional stacking of memory cells with alternating orientations (e.g., first set of cells oriented in one direction, second set in perpendicular direction). This dimensional arrangement increases storage density while distributing aspect ratio challenges across multiple layers and orientations, preventing structural collapse in any single dimension
Data Source
AI summary
A semiconductor device and method of manufacture are provided. In embodiments a memory array is formed by manufacturing portions of a word line during different and separate processes, thereby allowing the portions formed first to act as a structural support during later processes that would otherwise cause undesired damage to the structures.