Semiconductor Memory Device Void Covering Film Structure
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Solution Overview
Problem
The existing semiconductor memory devices, such as ReRAM with a VBL structure, face challenges in achieving uniform resistance distribution due to local thinning of bit lines, leading to variations in resistance and reduced yield, especially when the void covering film is not properly managed during manufacturing.
Innovation Solution
The implementation of a void covering film and an antioxidizing film with different materials and etching properties, deposited in a specific order and pattern, prevents penetration and facilitates easy removal of projecting portions, ensuring uniform resistance distribution and improved manufacturing yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a void covering film is not properly managed during manufacturing, then the manufacturing process is simpler, but resistance distribution becomes non-uniform due to local thinning of bit lines
Solution Approach 1:
The film structure is segmented into multiple functional layers: a void covering film (first film) that specifically covers voids, an antioxidizing film (second film) deposited over the first film, and a third film with different etching properties. This segmentation allows each layer to perform its specific function independently, preventing penetration and facilitating selective removal while maintaining resistance uniformity.
Solution Approach 2:
The void covering film is strategically positioned only where voids exist, providing localized protection. The antioxidizing film and third film are deposited in specific patterns that target areas prone to penetration or oxidation. This local quality approach ensures that films are applied precisely where needed rather than uniformly across all surfaces, maintaining resistance distribution uniformity while managing complexity.
2Manufacturing precision
If multiple films with different materials and etching properties are deposited in a specific order, then resistance distribution uniformity is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The void covering film is deposited first to preliminarily cover voids before subsequent films are applied. This preliminary action prevents penetration of later-deposited materials into voids, ensuring uniform resistance distribution. The antioxidizing film is then deposited over the first film to provide oxidation protection, and the third film with different etching properties is added to facilitate selective removal. Each preliminary action simplifies subsequent manufacturing steps.
Solution Approach 2:
The antioxidizing film acts as an intermediary layer between the void covering film and the variable resistance film. This intermediate layer prevents direct oxidation of the variable resistance film while allowing the void covering film to perform its function. The third film with different etching properties serves as another intermediary that facilitates selective removal processes, making the overall manufacturing process more manageable despite the multiple layers.
3Productivity
If the void covering film is easily removable, then manufacturing yield is improved, but the film may not provide sufficient protection during processing
Solution Approach 1:
The films are designed with different etching properties - the third film has etching properties that differ from the first and second films. This parameter change allows selective removal of the third film while the first and second films remain intact to provide protection. The void covering film and antioxidizing film are made easily removable through specific material selection, improving yield, while their protective function is maintained during critical processing stages through the multi-layer structure.
Solution Approach 2:
The film structure uses composite materials with different properties: the void covering film, antioxidizing film, and third film are made from materials with different etching rates and protective capabilities. This composite approach allows each material to be optimized for its specific function - some materials provide easy removability for high yield, while others provide robust protection during processing. The combination of these composite materials in a multi-layer structure resolves the contradiction between ease of removal and protection capability.
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 suppresses variations in resistance distribution, allowing for consistent voltage application to the variable resistance film, enhancing switching characteristics and manufacturing efficiency.
Implementation Method 1
The implementation of a void covering film and an antioxidizing film with different materials and etching properties, deposited in a specific order and pattern
Data Source
AI summary
A semiconductor memory device according to an embodiment comprises: a semiconductor substrate extending in a first direction and a second direction, the first and second directions intersecting each other; a first wiring line disposed above the semiconductor substrate and extending in the first direction; a second wiring line disposed above the semiconductor substrate and extending in a third direction, the third direction intersecting the first direction and the second direction; a variable resistance film disposed at an intersection of the first wiring line and the second wiring line; a first insulating film disposed aligned with the second wiring line in the first direction; a first film disposed between the first wiring line and the first insulating film; and a second film disposed between the first insulating film and the first film and configured from a material different from that of the first film.