3D NAND Slit Structures Using Metal Plugs to Stop Crack Growth
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Solution Overview
Problem
The high aspect ratio of slit structures in 3D NAND memory devices poses manufacturing challenges and increases the risk of defects due to voids and crack propagation, which can lead to short circuits and other defects.
Innovation Solution
Incorporating metal plugs, such as titanium, titanium nitride, and tungsten, at the ends of slit structures to prevent crack propagation and fill voids within the polysilicon fill material, thereby reducing defects and enhancing the structural integrity of the microelectronic device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of tiers in the stack is increased to increase memory device density, then storage capacity is improved, but manufacturing difficulty increases due to high aspect ratio slit structures
Solution Approach 1:
The slit structure is segmented into multiple sections along its length, with each section containing a separate void. This segmentation allows the continuous polysilicon fill material to be divided into manageable segments that can be independently managed, reducing the overall manufacturing difficulty while maintaining the high density required for increased storage capacity
Solution Approach 2:
The aspect ratio parameter of the slit structure is effectively managed by changing the fill material properties and using metal plugs. The polysilicon fill material is deposited in a controlled manner to create voids at specific positions, and metal plugs are added to provide structural support, thereby transforming the high aspect ratio challenge into a manageable structural configuration that enables both high density and manufacturability
2Adaptability or versatility
If slit structures with high aspect ratio are formed to define separate blocks, then device functionality is improved, but defect risk increases due to voids and crack propagation
Solution Approach 1:
Metal plugs are incorporated into the slit structure at strategic positions before final device operation. These metal plugs serve as preemptive reinforcement elements that cushion and prevent crack propagation through the polysilicon fill material, thereby reducing defect risk while maintaining the high aspect ratio slit structure needed for device functionality
Solution Approach 2:
The slit structure employs a composite material system consisting of polysilicon fill material combined with metal plugs. This composite structure leverages the electrical and structural properties of metal to reinforce the polysilicon, creating a more reliable high aspect ratio slit structure that maintains functionality while reducing susceptibility to defects from voids and crack propagation
Data Source
AI summary
A microelectronic device may include a stack structure comprising a vertically alternating sequence of insulative structures and conductive structures, the stack structure divided into block portions. The microelectronic device may additionally include slit structures horizontally interposed between the block portions of the stack structure. Each of the slit structures may include a dielectric liner covering side surfaces of the stack structure and an upper surface of an additional structure underlying the stack structure, and a plug structure comprising at least one metal surrounded by the dielectric liner.