Memory Array Bridge Structures for Block Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in memory array fabrication is the occurrence of 'block-bending' or 'block stack tipping/tilting' during the manufacturing process, which affects the longitudinal orientation and stability of memory blocks, leading to potential defects in the memory array structure.
Innovation Solution
The method involves forming a memory array with vertically-alternating insulative and conductive tiers, where horizontally-elongated trenches and channel openings are created to define laterally-spaced memory-block regions, and bridge material is used to form upwardly-open cup-like structures between these regions, with intervening material replacing sacrificial material to ensure electrical isolation and structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If memory blocks are formed using conventional fabrication methods, then memory cells can be created, but block-bending or block stack tipping/tilting occurs during manufacturing, affecting longitudinal orientation and stability
Solution Approach 1:
The method forms bridges between memory blocks before completing the full stack formation. These preliminary bridge structures provide mechanical support and orientation guidance during subsequent fabrication steps, preventing block-bending and tipping/tilting that would otherwise occur during manufacturing processes.
Solution Approach 2:
Bridge structures serve as intermediary elements connecting adjacent memory blocks. These bridges act as mediators that maintain spatial relationships and structural integrity between blocks, preventing direct contact that could cause tipping/tilting while ensuring proper longitudinal orientation throughout the fabrication process.
2Productivity
If memory blocks are closely spaced to increase density, then array capacity increases, but electrical isolation between blocks becomes difficult to maintain
Solution Approach 1:
Intervening material is placed between adjacent memory blocks as an intermediary layer. This material provides electrical isolation between closely-spaced blocks while occupying minimal space, enabling high array density without compromising the reliability of electrical isolation. The bridges also serve as intermediaries that maintain physical separation.
Solution Approach 2:
The structure uses composite material arrangements where bridges and intervening materials are integrated with the memory block stack. This composite approach allows closely-spaced blocks to maintain electrical isolation through the combined effect of insulating intervening material and structurally-supportive bridge elements.
3Reliability
If complex bridge structures are formed to prevent block-bending, then structural integrity improves, but fabrication complexity increases
Solution Approach 1:
The bridge structures are formed as preliminary elements early in the fabrication sequence, before complex stack formation steps. By establishing these support structures first, the method simplifies subsequent processing while ensuring structural integrity is maintained throughout manufacturing, avoiding the need for complex post-formation corrections.
Data Source
AI summary
A method used in forming a memory array comprising strings of memory cells comprises forming a stack comprising vertically-alternating first tiers and second tiers. The stack comprises laterally-spaced memory-block regions that have horizontally-elongated trenches there-between. Sacrificial material is formed in the trenches. Vertical recesses are formed in the sacrificial material. The vertical recesses extend across the trenches laterally-between and are longitudinally-spaced-along immediately-laterally-adjacent of the memory-block regions. Bridge material is formed in the vertical recesses to line and less-than-fill the vertical recesses and form bridges there-from that have an upwardly-open cup-like shape. The sacrificial material in the trenches is replaced with intervening material that is directly under the bridges. Additional methods and structures independent of methods are disclosed.