Replacement Gate Formation for 3D Memory Interdigitated Electrodes
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Solution Overview
Problem
Existing methods for forming three-dimensional memory arrays face constraints due to the need to limit temperatures during replacement gate formation to avoid damaging memory cells, which restricts the formation of metal materials in high-aspect ratio openings and voids.
Innovation Solution
Performing replacement gate formation before the formation of memory cells allows for higher temperatures, enabling the creation of an interdigitated electrode structure by forming alternating layers of oxide and nitride materials and subsequently removing the nitride layers to fill with metal, thereby overcoming temperature limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If replacement gate formation is performed after memory cell formation, then memory cells are protected from damage, but temperature must be limited which restricts metal material formation in high-aspect ratio openings
Solution Approach 1:
The replacement gate formation is performed before memory cell formation, allowing high-temperature processing to create metal materials in high-aspect ratio openings without risking damage to pre-formed memory cells. The sequence is reversed from conventional approaches: replacement gate structure is established first, then memory cells are formed subsequently at lower temperatures.
2Manufacturing precision
If higher temperatures are used for metal material formation, then formation in high-aspect ratio openings is improved, but memory cells may be damaged
Solution Approach 1:
The replacement gate structure is formed first using high-temperature processes that enable high-quality metal material deposition in high-aspect ratio openings. After this critical structure is established, memory cells are formed at lower temperatures, ensuring both manufacturing precision for the metal materials and protection of memory cell integrity.
Solution Approach 2:
The fabrication process is segmented into distinct stages: first forming the replacement gate structure with high-temperature metal material formation, then separately forming memory cells at lower temperatures. This segmentation allows each process to be optimized independently without compromising the other.
Data Source
AI summary
The present disclosure includes methods for replacement gate formation in memory, and apparatuses and systems including memory formed accordingly. An embodiment includes forming a first oxide material in an opening through alternating layers of a second oxide material and a nitride material. An array of openings can be formed through the first oxide material formed in the opening. The layers of the nitride material can be removed. A metal material can be formed in voids resulting from the removal of the layers of the nitride material.