3D Memory Staircase Support Structure Against Stiction Collapse
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Solution Overview
Problem
Conventional memory device fabrication techniques face challenges in preventing structural collapse at staircase regions due to stiction issues, which can lead to increased costs and reduced reliability, particularly when additional chemical process steps are required to mitigate these issues.
Innovation Solution
Incorporating support structures with specific dimensions and dimension ratios at staircase regions, and utilizing a reticle with patterned dimensions to form these structures during the fabrication process, thereby preventing collapse and enhancing the structural integrity of the memory device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional chemical process steps are used to prevent structural collapse, then structural stability is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The support structure is designed and formed in advance during the fabrication process, before the staircase structure is subjected to potential collapse risks. This preliminary structural reinforcement prevents the need for additional chemical process steps to mitigate collapse issues, thereby improving reliability without increasing manufacturing complexity
Solution Approach 2:
The support structure acts as an intermediary element between the substrate and the staircase structure. It provides mechanical support and distributes stresses, preventing direct contact and potential collapse of the staircase structure, thus eliminating the need for additional chemical protective steps
2Reliability
If additional chemical process steps are implemented to prevent collapse, then structural integrity is improved, but fabrication cost increases
Solution Approach 1:
The support structure is formed as an integral part of the device during the standard fabrication sequence, providing structural integrity from the outset. This eliminates the need for costly additional chemical process steps that would otherwise be required to prevent or repair collapse
Solution Approach 2:
The support structure is designed to automatically provide the necessary mechanical support and stress distribution without requiring external chemical treatments or additional process steps. The structure serves its own protective function, reducing fabrication costs
3Manufacturing precision
If support structures with specific dimensions are used, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The support structure is designed with specific dimensions and characteristics only at the critical staircase regions where collapse risk exists. The rest of the device maintains its standard simple structure. This localized approach improves manufacturing precision at critical points without significantly increasing overall device complexity
Solution Approach 2:
The support structure extends in the vertical dimension beneath the staircase structure, providing support without occupying additional lateral space. This vertical dimension approach allows precise dimensional control where needed while maintaining a compact overall device footprint
Data Source
AI summary
Some embodiments include apparatuses and methods of forming the apparatuses. One of the apparatuses includes tiers of respective memory cells and control gates, the tier located one over another over a substrate, the control gates including a control gate closest to the substrate, the control gates including respective portions forming a staircase structure; conductive contacts contacting the control gates at a location of the staircase structure, the conductive contacts including a conductive contact contacting the control gate; a dielectric structure located on sidewalls of the control gates; and support structures adjacent the conductive contacts and having lengths extending vertically from the substrate, the support structures including a support structure closest to the conductive contact, the support structure located at a distance from an edge of the dielectric structure, wherein a ratio of a width of the support structure over the distance is ranging from 1.6 to 2.0.