Backside Passivation Structure for Crack-Resistant 3D Memory
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Solution Overview
Problem
Three-dimensional memory devices face challenges in maintaining structural integrity and preventing cracks in their backside passivation structures, which can compromise device performance and reliability.
Innovation Solution
A crack-resistant backside passivation structure is implemented, comprising a specific configuration of horizontally-extending portions and connection via structures, along with a backside connection pad structure designed to enhance structural stability and prevent cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional backside passivation structure is used in three-dimensional memory devices, then the device can be manufactured with standard processes, but cracks develop in the passivation structure compromising structural integrity and reliability
Solution Approach 1:
The backside passivation structure is segmented into multiple horizontally-extending portions at different elevations rather than a single continuous layer. This segmentation allows each portion to independently support the structure above it, preventing crack propagation through the entire passivation structure while maintaining manufacturing feasibility through sequential deposition processes
Solution Approach 2:
Different regions of the backside passivation structure are given different properties through the horizontally-extending portions at specific elevations. These portions are strategically positioned to provide localized structural support and crack resistance where needed most, while other regions maintain standard passivation characteristics, thus balancing reliability enhancement with manufacturing simplicity
2Manufacturing precision
If the backside connection pad structure is simplified for easier manufacture, then manufacturing precision may be compromised leading to cracks and reduced device reliability
Solution Approach 1:
The horizontally-extending portions are formed as preliminary structural elements during the deposition process sequence. By establishing these support portions at specific elevations before final passivation layer completion, the structure is pre-configured for crack resistance, ensuring manufacturing precision is built-in rather than added as a corrective measure
Solution Approach 2:
The solution transitions from a two-dimensional planar passivation layer to a three-dimensional multi-elevation structure with horizontally-extending portions. This dimensional change provides additional structural support pathways that prevent crack propagation while maintaining compatibility with standard sequential deposition manufacturing processes
Data Source
AI summary
A three-dimensional memory device includes an alternating stack of insulating layers and electrically conductive layers, a three-dimensional array of memory elements embedded in the alternating stack, a dielectric material portion located adjacent to the alternating stack, connection via structures vertically extending through the dielectric material portion, a backside connection pad cavity vertically extending through the source layer, a backside isolation layer, and a backside connection pad structure including a proximal portion contacting end surfaces of the connection via structures. The backside connection pad structure includes a tapered connecting portion overlying a stepped connecting portion of the backside isolation layer, or dummy regions which do not contact the end surfaces of the connection via structures.