Memory Device Source Contact Distribution via Dummy Blocks
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Solution Overview
Problem
Memory devices face variations in voltage input to the common source line, which affect operating characteristics and reliability, as existing configurations lead to voltage differences based on location within the cell area.
Innovation Solution
The memory device incorporates source contacts connected to the common source line through dummy blocks between cell blocks, ensuring a stable voltage path from the source driver, reducing voltage differences and improving performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If source contacts are disposed only in cell blocks, then device complexity is reduced, but voltage variations in the common source line increase
Solution Approach 1:
Dummy blocks are introduced as intermediary structures between cell blocks to carry source contacts. These dummy blocks serve as mediators that provide additional voltage distribution paths without interfering with the normal cell operation, thus reducing voltage variations in the common source line while maintaining a systematic structure.
Solution Approach 2:
The cell area is segmented into alternating cell blocks and dummy blocks arranged in a striped pattern. This segmentation allows source contacts to be distributed across multiple discrete locations (both in cell blocks and dummy blocks), creating multiple parallel voltage distribution paths that reduce voltage variations along the common source line.
2Reliability
If source contacts are distributed throughout the cell area, then voltage variations are reduced, but manufacturing complexity increases
Solution Approach 1:
The cell area is divided into regular alternating patterns of cell blocks and dummy blocks. This segmentation creates a predictable, periodic structure that simplifies manufacturing by allowing standardized fabrication processes to be applied repeatedly across the substrate, despite the increased distribution of source contacts.
Solution Approach 2:
The invention changes the spatial distribution parameter of source contacts from concentrated to distributed, while maintaining the same contact structure design within each block. This parameter change achieves better voltage uniformity without requiring fundamentally different manufacturing techniques, as each individual contact structure remains similar.
3Ease of operation
If source contacts are concentrated in specific blocks, then device complexity is minimized, but operating characteristics deteriorate due to voltage differences
Solution Approach 1:
By distributing source contacts across both cell blocks and dummy blocks in a striped pattern, the invention creates multiple equipotential regions throughout the cell area. This ensures that different regions of the common source line maintain similar voltage levels during operation, improving operating characteristics by eliminating voltage-induced performance variations.
Solution Approach 2:
The contact distribution is segmented into discrete blocks with alternating functions (cell blocks and dummy blocks). This segmentation allows each block to independently contribute to voltage distribution, ensuring uniform voltage delivery to different regions of the memory array without requiring a monolithic complex structure.
Data Source
AI summary
A memory device includes a peripheral circuit area including a first substrate and circuit elements on the first substrate, at least a portion of the circuit elements providing a source driver, and a cell area including a second substrate stacked with the peripheral circuit area in a first direction, perpendicular to an upper surface of the first substrate, and cell blocks and dummy blocks arranged in a second direction, parallel to an upper surface of the second substrate. Each of the cell blocks includes gate electrode layers and insulating layers alternately stacked on the second substrate, and channel structures extending in the first direction to penetrate through the gate electrode layers and the insulating layers and to be connected to the second substrate, at least one source contact block, among the dummy blocks, includes a first dummy insulating region on the second substrate, and source contacts extending in the first direction, penetrating through the first dummy insulating region and connected to the second substrate, and the source contacts are connected to the source driver through metal wirings in an upper portion of the cell area.