Sacrificial Line Replacement for Phase Change Memory Stability
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Solution Overview
Problem
The challenge in forming high-density memory arrays with small feature sizes is the inadequate mechanical stability of intermediate structures during fabrication, leading to issues like warping and collapsing due to exposure to harsh processing environments, such as plasma or aqueous environments.
Innovation Solution
The use of temporary sacrificial materials with sufficient mechanical stability is employed in the fabrication process, which are later replaced with permanent functional materials like chalcogenide or conductive materials, using techniques such as lithographic patterning and etching, followed by dielectric filling and selective etching to form stable memory cell structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If small feature sizes are used to form high-density memory arrays, then storage density is improved, but mechanical stability of intermediate structures deteriorates
Solution Approach 1:
The patent introduces sacrificial materials as intermediary structures during fabrication. These sacrificial materials provide the necessary mechanical stability and structural support for forming small-geometry memory cells, and are later replaced with functional materials to complete the device.
Solution Approach 2:
The patent employs preliminary structuring where sacrificial materials are deposited and patterned before the actual memory cell formation. This preliminary structure provides mechanical stability during subsequent processing steps, enabling the fabrication of high-density arrays with small feature sizes.
2Ease of manufacture
If intermediate structures are exposed to harsh processing environments, then fabrication is completed, but warping and collapsing occur
Solution Approach 1:
Sacrificial materials serve as protective intermediary structures that withstand harsh processing environments such as plasma and aqueous environments. These materials are specifically chosen for their mechanical stability and resistance to processing conditions, preventing warping and collapsing of the memory cell structures.
Solution Approach 2:
The patent applies beforehand cushioning by depositing sacrificial materials that provide mechanical support and cushioning to intermediate structures before they are exposed to harsh processing environments. This prevents structural failure during fabrication.
3Stability of the object's composition
If sacrificial materials are used to maintain mechanical stability, then structural stability is improved, but device complexity increases
Solution Approach 1:
The patent extracts the mechanical support function from the final device structure by using separate sacrificial materials that are temporarily introduced during fabrication and then completely removed. This allows the functional memory cell structure to be simplified while maintaining stability during manufacturing.
Solution Approach 2:
The sacrificial materials are discarded after serving their temporary purpose of providing mechanical stability during fabrication. selective removal processes eliminate these sacrificial materials, leaving only the functional memory cell structures without the temporary support elements.
Data Source
AI summary
Methods of forming memory cells comprising phase change and/or chalcogenide materials are disclosed. In one aspect, the method includes providing a lower line stack extending in a first direction, the lower line stack comprising a sacrificial line over a lower conductive line. The method further includes forming a chalcogenide line extending in the first direction by selectively removing the sacrificial material of the sacrificial line and replacing the sacrificial line with a chalcogenide material.