Semiconductor Memory Device Insulating Film Segmentation
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Solution Overview
Problem
Current semiconductor memory devices face challenges in manufacturing efficiency due to hydrogen diffusion issues, leading to peeling of semiconductor films and increased costs, particularly in the formation of insulating films and their removal processes.
Innovation Solution
The use of high-density silicon nitride insulating films, such as those formed by LPCVD, is introduced between insulating films to reduce hydrogen diffusion, and low-density silicon nitride films are used on top surfaces to facilitate quicker removal, reducing the number of manufacturing processes and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional insulating films are used in semiconductor memory devices, then manufacturing processes are simpler, but hydrogen diffusion causes film peeling and reduces manufacturing yield
Solution Approach 1:
The insulating film structure is segmented into multiple layers: a first insulating film containing high-density silicon nitride, a second insulating film containing low-density silicon nitride, and a third insulating film. This segmentation allows each layer to perform its specific function - the high-density layer prevents hydrogen diffusion while the low-density layer facilitates etching removal, thereby resolving the contradiction between reliability and complexity.
Solution Approach 2:
Different regions of the insulating film structure have different densities and compositions. The first insulating film uses high-density silicon nitride for hydrogen barrier properties, while the second insulating film uses low-density silicon nitride for easy removal. This local quality differentiation enables each part to optimize its function, improving manufacturing yield without requiring complete structural redesign.
2Reliability
If high-density silicon nitride films are used to prevent hydrogen diffusion, then film peeling is reduced, but the number of manufacturing processes increases
Solution Approach 1:
The low-density silicon nitride film is formed in advance as a sacrificial layer that facilitates subsequent etching processes. This preliminary action enables the high-density silicon nitride layer to perform its hydrogen barrier function while the low-density layer is easily removed later, maintaining film adhesion without significantly increasing manufacturing complexity.
Solution Approach 2:
The low-density silicon nitride film acts as an intermediary layer between the high-density silicon nitride film and other structures. It serves as a buffer that is easily etched away, allowing the high-density layer to prevent hydrogen diffusion effectively while the intermediary layer simplifies the removal process, thereby maintaining productivity.
3Ease of manufacture
If low-density silicon nitride films are used on top surfaces for easier removal, then manufacturing costs are reduced, but hydrogen diffusion protection is compromised
Solution Approach 1:
The insulating film is segmented into distinct layers with different densities. The low-density silicon nitride film forms the second insulating film that is easily removed, while the high-density silicon nitride film forms the first insulating film that provides hydrogen barrier protection. This segmentation allows each layer to fulfill its specific function without compromising the other.
Solution Approach 2:
Different local regions of the insulating film structure have different densities optimized for their specific functions. The first insulating film has high density for hydrogen barrier properties, while the second insulating film has low density for easy removal. This local quality differentiation resolves the contradiction between ease of manufacture and reliability.
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 enhances manufacturing yield, reduces hydrogen diffusion, and minimizes film peeling, thereby improving the cost-effectiveness and efficiency of semiconductor memory device production.
Implementation Method 1
hydrogen diffusion issues, leading to peeling of semiconductor films
Data Source
AI summary
A semiconductor memory device includes: a substrate including a first and a second regions; first wiring layers disposed in a first direction; a second wiring layer; a third wiring layer closer to the substrate than the first and the second wiring layers; a semiconductor film that penetrates the first and the second wiring layers, and is connected to the third wiring layer; and a gate insulating film disposed between the semiconductor film and the first wiring layers. The first wiring layers include first conductive films opposed to the semiconductor film in the first region, and first films in the second region. The second wiring layer includes a second conductive film opposed to the semiconductor film in the first region, and a second film in the second region. The second film is different from the first films.