3D Memory Word Line Side-Contact Vias With Dielectric Isolation
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Solution Overview
Problem
Current three-dimensional memory devices face challenges in efficiently forming word line side-contact via structures that are electrically isolated and effectively integrated within the alternating stacks of insulating and conductive layers, which affects the device's performance and density.
Innovation Solution
A method involving the formation of alternating stacks of insulating and sacrificial material layers, followed by the creation of memory openings, fill structures, and the replacement of sacrificial layers with conductive layers, along with the formation of annular dielectric spacers and side-contact via structures that are laterally spaced and electrically isolated from other conductive layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional methods are used to form word line side-contact via structures, then the structures can be formed, but the process requires stepped surfaces and complex multi-step procedures reducing productivity
Solution Approach 1:
Annular dielectric spacers are formed in advance around contact openings before the conductive layers are deposited. This preliminary action creates pre-defined isolation structures that eliminate the need for subsequent stepped surface formation and complex alignment procedures, thereby improving manufacturing efficiency
Solution Approach 2:
The formation process is segmented into distinct stages: first forming annular spacers around contact openings, then depositing conductive layers, and finally forming via structures. This segmentation allows each step to be optimized independently and eliminates the need for complex integrated processes, improving ease of manufacture
2Reliability
If side-contact via structures are formed with proper electrical isolation, then device performance improves, but the structure complexity increases
Solution Approach 1:
Annular dielectric spacers serve as intermediary structures between the contact openings and the conductive layers. These spacers provide the necessary electrical isolation without requiring complex multi-layer isolation schemes, thereby improving reliability while maintaining structural simplicity
Solution Approach 2:
The annular dielectric spacers perform multiple functions simultaneously: they provide electrical isolation for the side-contact via structures, define the contact opening geometry, and serve as a template for subsequent material deposition. This multi-functionality reduces the need for additional specialized structures, lowering overall device complexity
Data Source
AI summary
A memory device includes at least one alternating stack of insulating layers and electrically conductive layers, memory openings vertically extending through each layer within the at least one alternating stack, memory opening fill structures located in the memory openings and containing a respective vertical semiconductor channel and a respective vertical stack of memory elements, and an electrically conductive side-contact via structure vertically extending through each layer within the at least one alternating stack and contacting a sidewall of one of the electrically conductive layers.