Air-Gap Stack Structures for Stable High-Density Memory Arrays
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Solution Overview
Problem
Conventional microelectronic device fabrication techniques face challenges in maintaining structural integrity due to chemical erosion during etching processes, which can lead to voids and collapse of tiers in vertical memory arrays, affecting the performance and density of memory devices.
Innovation Solution
The implementation of a stack structure with air gaps and a method involving sacrificial structures, etch stop films, and insulative fill materials to support conductive structures and prevent collapse, while also enhancing capacitive coupling inhibition through the use of air gaps with higher dielectric constants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional etching processes are used to form vertical memory arrays, then memory density can be increased through vertical stacking, but chemical erosion causes voids and collapse of tiers reducing structural integrity
Solution Approach 1:
The patent applies preliminary action by forming sacrificial structures and etch stop films before the main etching process. The etch stop films are deposited on the sacrificial structures in advance to prevent chemical erosion during subsequent etching operations, thereby maintaining structural integrity while enabling high memory density through vertical stacking.
Solution Approach 2:
The patent uses etch stop films as intermediary layers between the sacrificial structures and the etching environment. These intermediary films protect the sacrificial structures from chemical erosion during the etching process, preventing void formation and tier collapse while allowing the etching process to proceed for high-density memory formation.
2Object-generated harmful factors
If insulative structures are used to separate conductive structures, then capacitive coupling is reduced, but the dielectric constant is lower compared to air gaps
Solution Approach 1:
The patent applies the taking out principle by removing insulative structures from between conductive structures and replacing them with air gaps. This extraction eliminates the harmful capacitive coupling effect while utilizing air's superior dielectric properties (higher dielectric constant) to improve device performance.
Solution Approach 2:
The patent utilizes air gaps as a porous-like structure between conductive elements. The air-filled spaces act as effective dielectric separators with higher dielectric constants compared to conventional insulative materials, reducing capacitive coupling while maintaining structural separation.
3Quantity of substance
If dimensions of features are reduced to increase integration, then device density improves, but structural stability during fabrication becomes more difficult to maintain
Solution Approach 1:
The patent applies preliminary action by pre-forming etch stop films on sacrificial structures before dimensional reduction and etching processes. This preliminary protective layer ensures that even as feature dimensions are reduced to increase integration density, the structural stability is maintained during fabrication through the erosion-resistant etch stop films.
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
This approach improves the structural integrity and density of microelectronic devices by maintaining the shape of sacrificial structures and preventing collapse, while reducing capacitive coupling and enhancing feature density and scalability.
Implementation Method 1
enhancing capacitive coupling inhibition through the use of air gaps with higher dielectric constants
Data Source
AI summary
A microelectronic device comprises a stack structure, a staircase structure, an etch stop material, and insulative material. The stack structure comprises conductive structures, and air gaps vertically alternating with the conductive structures. The staircase structure is within the stack structure and has steps comprising edges of at least some of the conductive structures of the stack structure. The etch stop material continuously extends over the conductive structures and at least partially defines horizontal boundaries of the air gaps. The insulative material overlies the etch stop material. Additional microelectronic devices, memory devices, electronic systems, and methods are also disclosed.