Memory Capacitor Array Lining to Prevent Opening Pinch-Off
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Solution Overview
Problem
Existing memory technologies using ferroelectric capacitors face challenges in maintaining the polarization state during reading operations, often requiring immediate re-write of memory cells after reading, which can be undesirable.
Innovation Solution
The method involves forming an array of capacitors and memory cells with a specific structure that includes a stack of sacrificial material and insulative material, where an insulative lining is deposited with intermittent nitrogen-containing plasma exposure to prevent pinching off of openings and ensure accurate capacitor formation, allowing for stable polarization states without immediate re-write.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ferroelectric capacitor structures are used in memory cells, then non-volatile memory storage is achieved, but the polarization state is unstable during reading operations requiring immediate re-write
Solution Approach 1:
The patent applies local quality by creating a carbon-depleted region specifically at the interface between the insulative lining and sacrificial material, while maintaining normal carbon content in other regions. This localized modification prevents pinching off at the critical opening region without affecting the overall capacitor structure or requiring re-write operations
Solution Approach 2:
The patent performs preliminary action by depositing the insulative lining with controlled carbon depletion before the opening formation process. This pre-established carbon-depleted region prevents pinching off during subsequent processing steps, ensuring opening integrity is maintained throughout fabrication without requiring corrective re-write operations later
2Ease of manufacture
If insulative lining is deposited without nitrogen-containing plasma exposure, then deposition process is simpler, but openings pinch off during capacitor formation
Solution Approach 1:
The patent applies periodic action by intermittently exposing the insulative lining to nitrogen-containing plasma during the deposition process. This periodic plasma exposure creates the desired carbon-depleted region at the interface without requiring complete plasma processing, balancing process complexity with manufacturing precision
Solution Approach 2:
The patent changes the chemical composition parameter of the insulative lining by controlling carbon content through intermittent plasma exposure. This parameter change creates a carbon-depleted region that prevents pinching off, improving opening dimension control while maintaining reasonable process complexity
3Stability of the object's composition
If carbon content is uniformly distributed in insulative material, then material properties are consistent, but critical dimension of capacitors is reduced and pinching off occurs
Solution Approach 1:
The patent applies local quality by creating a carbon-depleted region specifically at the interface between the insulative lining and sacrificial material, while maintaining normal carbon content in other regions. This localized modification prevents pinching off at the critical opening region without affecting the overall capacitor structure or requiring re-write operations
Solution Approach 2:
The patent performs preliminary action by depositing the insulative lining with controlled carbon depletion before the opening formation process. This pre-established carbon-depleted region prevents pinching off during subsequent processing steps, ensuring opening integrity is maintained throughout fabrication without requiring corrective re-write operations later
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 the critical dimension of capacitors and reduces the risk of pinching off, resulting in improved capacitor performance and reduced need for immediate re-write operations, thereby stabilizing the memory states effectively.
Implementation Method 1
During the depositing, the insulative lining is intermittently exposed to a nitrogen-containing plasma
Implementation Method 2
An insulative lining is deposited within the horizontally-spaced openings and directly above the sacrificial material
Data Source
AI summary
A method used in forming an array of capacitors comprises forming horizontally-spaced openings into sacrificial material and through insulative material that is between a top and bottom of the sacrificial material. The insulative material at least predominately comprises at least one of a silicon nitride, a silicon boronitride, and a silicon carbonitride. The insulative material with horizontally-spaced openings there-through comprises an insulative horizontal lattice. An insulative lining is deposited within the horizontally-spaced openings and directly above the sacrificial material. The insulative lining at least predominately comprises at least one of a silicon oxide and a silicon oxynitride. During the depositing, the insulative lining is intermittently exposed to a nitrogen-containing plasma. First capacitor electrodes that are individually within individual of the horizontally-spaced openings are formed laterally over the insulative lining that is in the horizontally-spaced openings. The sacrificial material is removed and a capacitor insulator is formed over the first capacitor electrodes and the insulative horizontal lattice. Second-capacitor-electrode material is formed over the capacitor insulator. Structure independent of method is disclosed.