Y-Shaped Insulating Pillars for 3D Memory Stack Stability
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Solution Overview
Problem
The stability and reliability of three-dimensional (3D) memory devices are compromised due to the susceptibility of stacked memory cells to collapse, and the difficulty in forming conductive patterns with uniform thickness around channel pillars, which affects the integration density and manufacturing process.
Innovation Solution
The use of Y-shaped insulating pillars arranged in a matrix structure to define regions for channel pillars and conductive patterns, providing structural support and uniformity, with second and third insulating pillars extending in specific directions to stabilize the stack and ensure uniform conductive pattern thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of stacked memory cells is increased to increase integration density, then the integration density improves, but the stack structure becomes more susceptible to collapsing and reliability degrades
Solution Approach 1:
The patent divides the stack structure into multiple segments by introducing sacrificial pillars at different levels (first sacrificial pillars in lower layers, second sacrificial pillars in upper layers). This segmentation provides distributed support points throughout the stack, preventing catastrophic collapse while allowing high integration density. Each sacrificial pillar acts as an independent support element that can be selectively removed to form contact holes.
Solution Approach 2:
The sacrificial pillars are formed in advance during the manufacturing process before the final stack structure is completed. These preliminary support structures are strategically positioned to provide stability during subsequent processing steps, and are later removed to create the desired electrical contacts. This preliminary action ensures structural integrity throughout the manufacturing process.
2Reliability
If the thickness of the conductive pattern surrounding the channel pillar is increased for uniformity, then operating reliability improves, but forming the conductive pattern with uniform thickness becomes more difficult
Solution Approach 1:
The sacrificial pillars serve as intermediary structures that define the spacing and position of conductive patterns. By using these temporary support structures as physical guides, the conductive patterns are automatically positioned at uniform distances from channel pillars. The sacrificial pillars act as a mediator that translates the desired uniform thickness requirement into a physical constraint during the formation process, eliminating the need for complex control mechanisms.
Data Source
AI summary
A semiconductor device may include a first insulating pillar having a substantially Y-shaped cross-sectional structure to define first through third regions, channel pillars formed in the first through third regions, respectively, and second insulating pillars disposed opposite one another across the first through third regions. The semiconductor device may also include third insulating pillars disposed between the second insulating pillars and disposed opposite one another across the first through third regions. The third insulating pillars may extend in a direction intersecting the second insulating pillars.