3D Memory Stack Separation Structure to Prevent Bridge Defects
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Solution Overview
Problem
Existing semiconductor devices face challenges in increasing data storage capacity and reducing word line bridge defects and structural collapse due to the limitations of two-dimensional memory cell arrangements.
Innovation Solution
A manufacturing method involving the formation of a stacked structure with sacrificial insulating and interlayer layers, followed by the creation of separation and dummy holes, and a pullback process to remove sacrificial material, forming a seamless separation structure with protruding structures to support the stacked structure and prevent collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If two-dimensional memory cell arrangements are used, then manufacturing process is simpler, but data storage capacity is limited
Solution Approach 1:
The patent transitions from two-dimensional memory cell arrangement to three-dimensional stacked structure, where memory cells are arranged vertically across multiple layers. This dimensional change enables significantly increased data storage capacity by utilizing the vertical space above the substrate, allowing multiple memory cell layers to be stacked in the thickness direction of the substrate.
2Quantity of substance
If stacked structure is formed to increase storage capacity, then data storage capacity increases, but word line bridge defects occur
Solution Approach 1:
The patent introduces separation structures that extend from the substrate through the stacked structure to physically separate adjacent memory cell strings. This extraction of a separating element prevents conductive material from forming unwanted bridges between adjacent word lines during the filling process, thereby eliminating word line bridge defects while maintaining the high-density three-dimensional architecture.
Solution Approach 2:
The separation structure acts as an intermediary barrier between adjacent memory cell strings. By positioning the separation structure between the memory cell strings and filling it with insulating material, the patent creates a physical barrier that prevents direct contact between conductive materials from adjacent strings, thus preventing word line bridge defects.
3Quantity of substance
If stacked structure is formed to increase storage capacity, then data storage capacity increases, but structural collapse occurs
Solution Approach 1:
The patent divides the continuous stacked structure into discrete segments by introducing separation structures at regular intervals. These separation structures create independent support zones that prevent the entire stacked structure from collapsing as a single unit, distributing mechanical stress and enhancing overall structural stability.
Solution Approach 2:
The separation structures serve as intermediary support elements within the stacked structure. By extending from the substrate through multiple memory cell layers, these separation structures provide internal scaffolding that maintains the integrity of the stacked architecture and prevents collapse during and after the manufacturing process.
4Device complexity
If separation structure is formed by expanding separation holes, then separation structure is created, but sacrificial material removal becomes complex
Solution Approach 1:
The patent performs preliminary actions by forming the separation holes and filling them with sacrificial material before constructing the stacked structure. This preliminary preparation allows the sacrificial material to be positioned exactly where needed, and enables selective removal through pullback processes that exploit the pre-established hole structures, simplifying the overall manufacturing sequence.
Solution Approach 2:
The patent inverts the conventional sequence by first forming the separation structures with sacrificial material, then building the stacked structure around them, and finally removing the sacrificial material through pullback. This inverted approach allows the separation structures to be formed more easily in advance, and the sacrificial material removal to be performed selectively after the stacked structure is in place, simplifying the manufacturing process.
Data Source
AI summary
A method of manufacturing a semiconductor device includes forming a stacked structure including a plurality of sacrificial insulating layers and a plurality of interlayer insulating layers alternately stacked on a substrate, forming a separation structure penetrating the stacked structure, depositing a sacrificial material inside the separation structure, forming a plurality of dummy holes penetrating the stacked structure, and performing a first pullback to remove a first portion of the plurality of sacrificial insulating layers connected to the plurality of dummy holes through the plurality of dummy holes, after the sacrificial material is deposited inside the separation structure.