On-Chip Capacitors in 3D Semiconductor Devices
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Solution Overview
Problem
Conventional on-chip capacitors in 3D semiconductor devices occupy significant die area and limit device shrinkage, and their design restricts metal routing flexibility, especially in stacked chip configurations where large capacitors hinder the miniaturization of peripheral circuits.
Innovation Solution
The integration of on-chip capacitors within dummy staircase regions of 3D semiconductor devices, where word lines/gate lines are electrically separated to form capacitors using gate-to-gate dielectric layers, allowing for increased capacitance density without expanding the die size and simplifying metal routing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional on-chip capacitors are used in 3D semiconductor devices, then the capacitor function is achieved, but the die area occupied is significant and device shrinkage is limited
Solution Approach 1:
The patent transitions from planar capacitor designs to three-dimensional capacitor structures by utilizing vertically interleaved conductive layers and dielectric layers. The capacitor electrodes are formed at different heights within the memory stack, creating a 3D configuration that increases capacitance density while reducing the planar die area occupied by capacitors.
Solution Approach 2:
The capacitor structure is nested within the existing memory stack architecture. The capacitor electrodes are formed using the same vertically interleaved conductive layers that constitute the memory structure, effectively nesting the capacitor function within the memory device footprint without requiring separate dedicated capacitor area.
2Adaptability or versatility
If conventional capacitor designs are used, then capacitor functionality is provided, but metal routing flexibility is restricted
Solution Approach 1:
By forming capacitor contacts at different vertical levels within the 3D memory stack, the patent enables flexible metal routing paths. The staggered arrangement of capacitor electrodes allows interconnect layers to access capacitor terminals from different heights, providing multiple routing options and improving metal routing flexibility while maintaining compact die area.
3Quantity of substance
If capacitance density is increased using conventional methods, then capacitor performance improves, but die area expands
Solution Approach 1:
The patent achieves high capacitance density by exploiting the vertical dimension within the memory stack. Multiple capacitor electrodes are stacked at different heights, with dielectric layers between them, creating a 3D capacitor array that packs more capacitance into the same planar footprint, thereby increasing capacitance density without expanding die area.
Solution Approach 2:
The patent merges the capacitor structure with the memory stack structure by using the same vertically interleaved conductive and dielectric layers for both memory and capacitor functions. This integration allows the capacitor elements to share the vertical space of the memory device, achieving high capacitance density within the existing device footprint.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables increased capacitance density and simplifies metal routing in 3D semiconductor devices, facilitating device miniaturization and improving the flexibility of chip design without increasing the planar die size.
Implementation Method 1
Capacitors include two conductive plates separated by an insulating material
Implementation Method 2
The isolation structure extends vertically through at least part of the memory stack to electrically separate at least some of the conductive layers into gate electrodes in a core array region and capacitor electrodes in a dummy staircase region
Data Source
AI summary
Embodiments of three-dimensional (3D) semiconductor devices and methods for forming the same are disclosed. In an example, a 3D memory device includes a memory stack, an isolation structure, and a plurality of capacitor contacts. The memory stack includes vertically interleaved conductive layers and first dielectric layers. The isolation structure extends vertically through at least part of the memory stack to electrically separate the conductive layers into gate electrodes in a core array region and capacitor electrodes in a dummy staircase region. The plurality of capacitor contacts are in contact with at least two of the capacitor electrodes in the dummy staircase region, respectively.