ReRAM Pillar Pitch Reduction via Segmented Columnar Members
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Solution Overview
Problem
Current technologies for reducing the pitch of pillars in resistive random access memory (ReRAM) devices face challenges in end treatment, leading to inefficiencies in forming memory cell arrays at high densities.
Innovation Solution
A method involving the formation of columnar members with specific shapes and orientations, followed by the deposition of a sidewall film, selective removal of these members, and embedding materials to create embedded layers, which are then used to form memory cells through lithography and etching, allowing for the formation of memory cell arrays with reduced pitch and prevention of short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional sidewall transfer technology with loop-cut is used for pitch reduction, then pillar pitch can be reduced, but end treatment becomes problematic and prevents further pitch reduction
Solution Approach 1:
The patent segments the columnar members into different types: first columnar members within the memory cell array forming region and second columnar members extending beyond the array boundaries. This segmentation allows different treatments for different regions, enabling pitch reduction while providing proper end treatment through the extended second columnar members that prevent short circuits and allow complete pattern transfer.
Solution Approach 2:
The patent performs preliminary action by extending the second columnar members beyond the memory cell array boundaries before forming the sidewall film and embedding material. This preliminary extension ensures that end treatment structures are already in place before subsequent processing steps, preventing short circuits and enabling complete pattern transfer without requiring complex loop-cut operations.
2Quantity of substance
If pillar pitch is reduced to increase memory density, then manufacturing complexity increases due to inadequate end treatment technology
Solution Approach 1:
By segmenting columnar members into first and second types with different spatial extents, the patent enables high-density memory cell arrays while simplifying the manufacturing process. The second columnar members provide built-in end treatment that eliminates the need for complex loop-cut operations, making high-density fabrication more manageable.
Solution Approach 2:
The second columnar members serve multiple functions: they extend beyond array boundaries to provide end treatment, prevent short circuits between adjacent memory cells, and enable complete pattern transfer during lithography. This multi-functionality reduces manufacturing complexity while maintaining high memory density.
3Ease of manufacture
If standard columnar members are used without extension, then manufacturing is simpler, but short circuits occur and pitch reduction is limited
Solution Approach 1:
The patent segments columnar members into first columnar members for memory cell formation and second columnar members extending beyond the array. This segmentation allows the second members to provide electrical isolation and prevent short circuits while maintaining simple manufacturing processes for forming the columnar structures themselves.
Solution Approach 2:
The second columnar members act as intermediary structures that extend beyond the memory cell array boundaries. These intermediary structures provide electrical isolation and prevent short circuits between adjacent memory cells, while also serving as templates for forming the sidewall film and embedding material during subsequent processing steps.
Data Source
AI summary
A method of manufacturing a nonvolatile storage device having memory cell arrays according to an embodiment of the present invention includes forming, in a memory cell array forming region above a processed film, first columnar members arrayed at substantially equal intervals in the first direction and the second direction, forming, concerning at least arrays as a part of arrays of the first columnar members in the first direction, second columnar members long in section having major axes longer than sections of the first columnar members outside of the memory cell array forming region such that the major axes are set in the first direction and the second columnar members continue to ends of the arrays, and forming, in the same manner as above, third columnar members, which continue to arrays of the first columnar members in the second direction.