Crown-Shaped Capacitor Series Connection for Footprint Reduction
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Solution Overview
Problem
The use of crown-shaped capacitors as compensation capacitance elements in semiconductor devices, such as DRAM, faces challenges including increased voltage fluctuations and dielectric breakdown due to high aspect ratios, leading to cavity formation in interlayer insulating films and reduced fabrication yield, while conventional methods to address these issues either increase the footprint or require additional guard ring regions.
Innovation Solution
The capacitors are arranged with adjacent blocks connected in series, where the lower electrodes are positioned close to each other, and the gap between them is filled with an upper electrode, preventing cavity formation and reducing the footprint by ensuring the upper electrode film thickness is two or less times the total film thickness, thereby avoiding dielectric breakdown and maintaining a compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If crown-shaped capacitors are used as compensation capacitance elements, then the footprint is reduced, but cavity formation occurs in interlayer insulating films
Solution Approach 1:
The patent transitions from planar capacitors to three-dimensional crown-shaped capacitors, utilizing vertical space to increase capacitance without increasing footprint. The crown shape allows the electrode to extend upward, effectively using the third dimension to achieve higher capacitance density while maintaining a compact planar footprint.
Solution Approach 2:
The patent introduces a support film as an intermediary structure between the lower electrode and the upper electrode/dielectric layer. This support film prevents cavity formation by providing mechanical support to the high-aspect-ratio crown-shaped electrode, ensuring structural integrity during fabrication processes while allowing the electrode to maintain its compact three-dimensional form.
2Area of stationary object
If high aspect ratio crown-shaped electrodes are used, then the footprint is reduced, but dielectric breakdown occurs
Solution Approach 1:
The patent uses three-dimensional crown-shaped electrodes instead of planar structures, allowing the electrode to extend vertically. This dimensional change increases the distance between electrodes without increasing footprint, thereby reducing electric field intensity and preventing dielectric breakdown while maintaining compact size.
Solution Approach 2:
The patent modifies the electrode geometry from planar to crown-shaped, changing the physical parameters of the structure. This geometric transformation increases the electrode surface area and vertical distance, altering the electric field distribution to reduce stress on the dielectric layer and prevent breakdown.
3Stability of the object's composition
If guard ring regions are provided to support capacitors, then collapsing is prevented, but the footprint increases
Solution Approach 1:
The patent merges the support function into the main capacitor structure by using a support film that is integrated with the crown-shaped electrode fabrication process. The support film is formed concurrently with the electrode structure, eliminating the need for separate guard ring regions and reducing overall footprint while maintaining electrode stability.
Solution Approach 2:
The crown-shaped electrode structure is designed to be self-supporting through its geometric configuration, with the curved walls providing inherent structural stability. The support film reinforces this self-supporting capability, allowing the electrode to maintain its shape without requiring additional guard ring structures, thereby reducing footprint.
Data Source
AI summary
Capacitance blocks (first block and second block) respectively formed on two different adjacent common pad electrodes are electrically connected in series through an upper electrode. A distance between two adjacent capacitance blocks connected in series through an upper electrode film for the upper electrode corresponds to a distance between opposing lower electrodes disposed in an outermost perimeter of each capacitance block, and is two or less times than a total film thickness of the upper electrode film embedded between the two adjacent capacitance blocks.