3D Memory Support Pillar Structures for Strength and Connectivity
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Solution Overview
Problem
Existing three-dimensional memory devices face challenges in efficiently forming support pillar structures that provide structural integrity and electrical connectivity within the alternating stack of insulating and conductive layers.
Innovation Solution
The formation of three-dimensional memory devices involves creating alternating stacks of insulating and sacrificial material layers, followed by patterning to form memory and support openings, depositing dielectric spacer material, and replacing sacrificial layers with electrically conductive layers, resulting in various types of support pillar structures that include dummy vertical semiconductor channels and dielectric spacers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If support pillar structures are formed in three-dimensional memory devices, then structural integrity is improved, but device complexity increases
Solution Approach 1:
The support pillar structures are segmented into multiple types: first support pillar structures containing semiconductor material and second support pillar structures containing only dielectric material. This segmentation allows different regions of the memory device to have appropriately tailored structural support without uniformly increasing complexity throughout the entire device.
Solution Approach 2:
Different types of support pillar structures are placed in different regions of the memory device based on local requirements. The first support pillar structures with semiconductor material are positioned where electrical connectivity is needed, while the second support pillar structures with only dielectric material are positioned where structural support suffices. This local differentiation optimizes the balance between structural integrity and device complexity.
2Reliability
If multiple types of support pillar structures are formed, then electrical connectivity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The method employs preliminary patterning actions where a first set of openings and a second set of openings are formed through sequential patterning steps. The first support pillar structures are formed in the first set of openings, and the second support pillar structures are formed in the second set of openings. This preliminary differentiation of opening locations and characteristics simplifies subsequent formation steps and reduces the overall manufacturing precision requirements by breaking down a complex single-step process into manageable sequential steps.
Data Source
AI summary
A three-dimensional memory device includes an alternating stack of insulating layers and electrically conductive layers, memory opening fill structures located within a respective memory opening vertically extending through the alternating stack in a memory array region, and support pillar structures vertically extending through the alternating stack. Each of the memory opening fill structures includes a respective vertical semiconductor channel and a respective memory film that contacts each layer within the alternating stack. Each of the support pillar structures includes a respective dummy vertical semiconductor channel, a respective dummy memory film, and at least one respective dielectric spacer material portion laterally surrounding the respective dummy memory film and interposed between the electrically conductive layers and the respective dummy memory film.