Alignment Key Structure for Multilayer Memory Channel Formation
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Solution Overview
Problem
The increasing complexity of processes for forming three-dimensionally arranged memory cells in semiconductor devices has made it difficult to enhance data storage capacity effectively.
Innovation Solution
A semiconductor device with a multilayer structure comprising alternately stacked insulating and wiring layers, including channel holes and alignment keys that protrude beyond the uppermost layer, facilitating efficient alignment and formation of channel structures across multiple layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If three-dimensionally arranged memory cells are provided to increase data storage capacity, then data storage capacity is improved, but process complexity increases
Solution Approach 1:
Alignment keys are formed in advance within the auxiliary stack structure before the main stack structure is constructed. These pre-formed alignment keys serve as reference markers that guide subsequent alignment operations, eliminating the need for complex real-time alignment procedures and reducing overall process complexity while enabling three-dimensional memory cell arrangement
Solution Approach 2:
An auxiliary stack structure is introduced as an intermediary element that contains alignment keys. This auxiliary structure acts as a template or guide for forming the main stack structure with channel holes. The auxiliary stack structure mediates the alignment process between different layers, simplifying the formation of three-dimensionally arranged memory cells without requiring direct complex alignment between all layers
2Manufacturing precision
If alignment keys protrude beyond the uppermost layer to facilitate alignment, then alignment precision is improved, but device structure complexity increases
Solution Approach 1:
The alignment function is extracted and concentrated into separate alignment keys that protrude from the auxiliary stack structure. These alignment keys are distinct, isolated elements that serve solely for alignment purposes, while the main stack structure focuses on containing the memory cells. This separation of functions improves alignment precision without significantly complicating the overall device structure
Solution Approach 2:
Alignment keys are extended in the vertical dimension to protrude beyond the uppermost layer of the auxiliary stack structure. This vertical extension provides accessible alignment references for subsequent processing steps without requiring additional lateral complexity. The protruding alignment keys create a clear dimensional hierarchy that simplifies the alignment process across multiple layers
Data Source
AI summary
A semiconductor device includes a first stack structure on a substrate, and a second stack structure on the first stack structure. A channel structure extends through the first stack structure and the second stack structure. A first auxiliary stack structure including a plurality of first insulating layers and a plurality of first mold layers are alternately stacked on the substrate. An alignment key extends into the first auxiliary stack structure and protrudes to a higher level than an uppermost end of the first stack structure. A second auxiliary stack structure is disposed on the first auxiliary stack structure and the alignment key, and includes a plurality of second insulating layers and a plurality of second mold layers alternately stacked. The second auxiliary stack structure includes a protrusion aligned with the alignment key.