Buried Bit Line Memory Layout for Dense, Low-Coupling Cells
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Solution Overview
Problem
Current semiconductor devices face challenges in increasing integration density and improving electrical and reliability characteristics, particularly in achieving fast operating speeds with low power consumption and high integration density.
Innovation Solution
The semiconductor device incorporates a substrate with an insulating layer, featuring bit lines disposed within the insulating substrate, buried node contacts, and word lines that cross active patterns, allowing for efficient integration and reduced coupling between bit lines, thereby enhancing integration density and electrical reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If bit lines are disposed in the insulating substrate with reduced spacing, then integration density is improved, but coupling phenomena between bit lines increase causing electrical reliability degradation
Solution Approach 1:
A ground line is introduced as an intermediary element disposed between adjacent bit lines within the insulating substrate. This ground line acts as a shield that reduces electromagnetic coupling and interference between the bit lines, thereby maintaining electrical reliability while allowing the bit lines to be spaced closer together for improved integration density.
Solution Approach 2:
The bit lines are disposed within the insulating substrate in a three-dimensional configuration rather than on a single planar surface. By utilizing the vertical dimension within the substrate, bit lines can be arranged with reduced spacing while maintaining electrical isolation through the insulating material, thus improving integration density without significantly increasing coupling phenomena.
2Productivity
If bit lines are disposed closer together to increase integration density, then more memory cells can be integrated, but manufacturing precision requirements increase
Solution Approach 1:
The bit lines, ground lines, and other conductive structures are pre-formed within the insulating substrate using advanced fabrication techniques such as self-aligned processes. This preliminary formation of interconnect structures with precise positioning reduces the need for subsequent high-precision alignment steps, thereby enabling closer bit line spacing while maintaining manufacturability.
3Productivity
If substrate thickness is increased to accommodate more bit lines, then integration density is improved, but device complexity increases
Solution Approach 1:
The substrate is segmented into multiple functional layers including the insulating substrate layer, active pattern layer, and various interconnect layers. This segmentation allows bit lines to be disposed at different vertical levels and positions within the substrate, enabling higher integration density while managing complexity through modular layer design that simplifies fabrication and testing.
Data Source
AI summary
A semiconductor device may include a substrate including an insulating substrate. A semiconductor layer is on the substrate. An active pattern is on the semiconductor layer. A bit line is disposed in the insulating substrate. The bit line extends along a first direction parallel to a bottom surface of the substrate. A buried node contact penetrates the semiconductor layer in a direction perpendicular to the bottom surface of the substrate. A word line penetrates the active pattern in a second direction that is parallel to the bottom surface of the substrate and crosses the first direction. The active pattern may be connected to the bit line through the buried node contact. A top surface of the buried node contact may be higher than a bottom surface of the active pattern.