3D Memory Staircase Dummy Channels Strengthened by Oxidation
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Solution Overview
Problem
Conventional methods for filling dummy channel holes in 3D memory devices result in low-quality oxide filling, leading to structural instability and collapse of the staircase structure when conductive layers replace sacrificial layers, due to the weight difference and insufficient structural support.
Innovation Solution
An oxidation process is performed to strengthen the dummy channel structure by oxidizing nitride materials within the dummy channel holes, creating an oxide layer that expands and enhances the structural stability, allowing it to support the weight of conductive layers effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional filling methods are used to fill dummy channel holes, then the filling process is simple, but the oxide quality is low and the staircase structure collapses
Solution Approach 1:
The patent applies preliminary action by performing an oxidation process on the dummy channel structure before filling it with oxide material. This pre-oxidation treatment strengthens the dummy channel structure, creating a robust framework that can support the subsequent oxide filling and prevent staircase structure collapse during later manufacturing steps.
Solution Approach 2:
The patent changes the physical-chemical parameters of the dummy channel structure by oxidizing it. This transformation modifies the material properties, converting the dummy channel material into a form with superior mechanical strength and structural stability, enabling it to bear the weight of conductive layers without causing collapse.
2Strength
If the dummy channel structure is not strengthened, then the manufacturing process is simpler, but the staircase structure collapses when conductive layers replace sacrificial layers
Solution Approach 1:
The oxidation process is performed as a preliminary action before the gate replacement step where conductive layers replace sacrificial layers. This timing ensures the dummy channel structure is strengthened in advance, providing the necessary structural support when the heavier conductive layers are introduced into the device.
3Manufacturing precision
If conventional filling methods are used, then the process is faster, but the oxide filling quality is insufficient to support conductive layers
Solution Approach 1:
The oxidation process fundamentally changes the parameters of the dummy channel material, transforming it into a high-strength oxide structure. This parameter change enables the structure to achieve the necessary mechanical properties to support conductive layers, thereby improving oxide filling quality and preventing structural collapse.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The strengthened dummy channel structure prevents collapse of the staircase structure, ensuring the stability and integrity of the 3D memory device by providing sufficient support for the conductive layers, thereby enhancing memory device performance and reliability.
Implementation Method 1
An oxidation process is performed to strengthen the dummy channel structure by oxidizing nitride materials within the dummy channel holes
Implementation Method 2
creating an oxide layer that expands and enhances the structural stability
Data Source
AI summary
Three-dimensional (3D) memory devices and methods for forming the 3D memory devices are provided. In one example, a 3D memory device includes a substrate and a memory stack including interleaved conductive layers and dielectric layers on the substrate. The memory stack includes a core structure and a staircase structure. The staircase structure is on one side of the memory stack. The 3D memory device also includes a dummy channel structure extending vertically through the staircase structure. The dummy channel structure includes a plurality of sections along a vertical side of the dummy channel structure. The plurality of sections respectively interface with the interleaved conductive layers in the staircase structure. At least one of the plurality of sections includes a non-flat surface at an interface between the at least one of the plurality of sections and a corresponding conductive layer.