Reinforced Vertical NAND Structure for Structural Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current VNAND process flows are limited by structural instability during high aspect ratio wet etch/deep trench processing, leading to fractures and collapse of wordlines, which restricts the maximum manufacturable size to around 64 bits.
Innovation Solution
A reinforced VNAND structure is developed using interleaved oxide and nitride layers with a reinforcing layer of materials like silicon oxide, silicon nitride, hafnium oxide, and aluminum oxide, which provides mechanical support and can be selectively etched to form distinct sheets and bridges between vertical structures, increasing structural stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high aspect ratio wet etch/deep trench processing is used to increase bitline capacity, then memory capacity increases, but structural instability occurs leading to fractures and collapse of wordlines
Solution Approach 1:
The patent introduces a reinforcing layer composed of materials with high Young's modulus (such as silicon oxide, silicon nitride, hafnium oxide, or aluminum oxide) integrated within the interleaved oxide and nitride layers. This composite structure provides mechanical reinforcement to the wordlines, enabling them to withstand the structural stresses of high aspect ratio etching and deep trench processing without fracturing or collapsing, thereby allowing increased bitline capacity while maintaining structural stability.
Solution Approach 2:
The patent modifies the mechanical parameters of the memory structure by incorporating materials with specifically high Young's modulus values into the reinforcing layer. This parameter change in material stiffness directly addresses the structural instability issue during high aspect ratio processing, allowing the wordlines to maintain their integrity under increased mechanical stress while supporting larger bitline capacities.
2Quantity of substance
If wordline size is increased beyond 64 bits to enhance memory capacity, then storage capacity increases, but structural fractures and collapse occur
Solution Approach 1:
The reinforcing layer made from materials with high Young's modulus (silicon oxide, silicon nitride, hafnium oxide, or aluminum oxide) is integrated within the interleaved oxide and nitride layers to provide mechanical reinforcement. This composite structure significantly enhances wordline strength, enabling wordlines to extend beyond the conventional 64-bit limit while maintaining structural integrity and preventing fractures and collapse during high aspect ratio wet etch and deep trench processing.
Solution Approach 2:
The reinforcing layer is selectively positioned at critical locations within the memory structure where mechanical support is most needed. By placing the high Young's modulus material locally within the interleaved layers, the patent provides targeted reinforcement to the wordlines at the points of highest stress during processing, enabling extended wordline lengths beyond 64 bits without compromising structural strength.
Data Source
AI summary
A reinforced vertical-NAND structure is provided. The reinforced vertical-NAND structure includes a first set of interleaved oxide and nitride layers formed into first and second vertical structures. The first vertical structure rises from a first section of a substrate and the second vertical structure rises from a second section of the substrate. The reinforced vertical-NAND structure also includes a reinforcing layer and a second set of interleaved oxide and nitride layers formed into third and fourth vertical structures. The reinforcing layer includes sheets, which are distinct and laid across respective tops of the first and second vertical structures, and bridges connecting the sheets. The third vertical structure rises from the sheet corresponding to the first vertical structure and the fourth vertical structure rises from the sheet corresponding to the second vertical structure.