Memory Array Dielectric Layout for Void-Safe Top Contacts
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Solution Overview
Problem
Current memory array structures in NAND flash memory devices face challenges in optimizing the fabrication process, particularly in forming top contacts over data lines without breaching adjacent voids, which can lead to inefficiencies and reliability issues.
Innovation Solution
The proposed solution involves forming a solid dielectric material between data lines to prevent void formation and ensuring that top contacts are adequately sized and positioned to avoid breaching these voids, thereby enhancing contact integrity and reducing fabrication complexities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If top contacts are formed over data lines in conventional NAND flash memory fabrication, then electrical connection is achieved, but adjacent voids may be breached leading to reliability issues
Solution Approach 1:
A solid dielectric material is formed between data lines before top contact formation to preemptively prevent void creation. This preliminary structural preparation ensures that when top contacts are subsequently formed, there is already a barrier in place to prevent void breaches, thereby improving contact integrity without compromising reliability.
Solution Approach 2:
The solid dielectric material acts as an intermediary layer between data lines and top contacts. This intermediate structure serves as a protective barrier that prevents direct interaction between the top contact formation process and potential voids, thereby eliminating the harmful effect of void breaches while maintaining electrical connectivity.
2Reliability
If solid dielectric material is formed between data lines to prevent void formation, then contact integrity is improved, but fabrication process complexity increases
Solution Approach 1:
The fabrication process utilizes parameter changes in the dielectric material properties, specifically transitioning from a void-containing structure to a solid dielectric structure between data lines. This parameter change (from void to solid material) is achieved through controlled deposition or filling processes that modify the physical state and density of the material in the inter-data-line region, thereby preventing void formation while maintaining process feasibility.
3Reliability
If top contacts are adequately sized and positioned to avoid void breaches, then reliability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The solid dielectric material is formed between data lines before top contact patterning and formation. This preliminary structural preparation establishes a protective barrier that reduces the precision requirements for subsequent top contact alignment, as the dielectric layer provides a buffer that prevents void breaches even with moderate positioning variations.
Data Source
AI summary
Memory array structures might include a first data line selectively connected to a first plurality of memory cells, a second data line selectively connected to a second plurality of memory cells, a solid first dielectric extending between a first portion of the first data line and a first portion of the second data line, a second dielectric containing a void extending between a second portion of the first data line and a second portion of the second data line, and a top contact overlying and in contact with the first portion of the first data line.