3D Memory Crest Contacts for Signal Isolation and Stack Support
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Solution Overview
Problem
Conventional methods of forming memory devices result in undesirable signal results and physical damage due to the formation of contact structures in vertical memory arrays.
Innovation Solution
The formation of contact structures through a stack structure, including staircase structures, with vertically extending contact structures that are configured to be electrically active or inactive, providing support during processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contact structures are formed through the stack structure in conventional methods, then electrical connections are established, but signal interference and physical damage occur
Solution Approach 1:
The contact structures are segmented into multiple types: first contact structures that are electrically active and connect to conductive structures, and second contact structures that are electrically inactive and serve as support structures. This segmentation allows the device to establish necessary electrical connections while avoiding harmful signal interference and physical damage that would occur with conventional uniform contact structure formation.
2Quantity of substance
If vertical memory array architecture is used to increase memory density, then more memory cells fit in unit die area, but complex processing is required to form electrical connections
Solution Approach 1:
Different regions of the stack structure are assigned different local qualities: crest regions contain contact structures (both active and inactive), while bridge regions contain filling material. The contact structures are further differentiated by electrical activity status. This local quality differentiation simplifies the processing required to form electrical connections while maintaining high memory density, as each region is optimized for its specific function.
3Ease of manufacture
If support structures are formed during processing, then manufacturing stability is improved, but additional structures increase device complexity
Solution Approach 1:
The support function is merged with the contact structures themselves. The second contact structures serve dual purposes: they provide mechanical support during processing (improving ease of manufacture) and are integrated into the final device architecture as part of the contact structure array (avoiding additional complexity from separate support structures). This merging eliminates the need for distinct temporary support elements that would increase device complexity.
Data Source
AI summary
A microelectronic device includes a stack structure comprising a vertically alternating sequence of conductive material and insulative material arranged in tiers, the stack structure divided into blocks by filled slot structures, each of the blocks comprising: a memory array region; staircase structures having steps; and crest regions interposed in a first horizontal direction between horizontally neighboring pairs of the staircase structures, and contact structures within the first crest region of each of the blocks and vertically extending through the stack structure to a source tier underlying the stack structure, the contact structures comprising: first contact structures in electrical communication with control logic circuitry; and second contact structures electrically isolated from the control logic circuitry, at least some the first contact structures relatively more centrally positioned with each of the blocks in a second horizontal direction orthogonal to the first horizontal direction than at least some of the second contact structures.