DRAM Capacitor Array Support Structure Against Lateral Deformation
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Solution Overview
Problem
The miniaturization of Dynamic Random Access Memory (DRAM) in mobile devices leads to reduced capacitor size and increased density, resulting in decreased stability and the risk of short circuits due to lateral deformation of capacitors.
Innovation Solution
A semiconductor device with a capacitor array supported by a surrounding structure that includes conductive contact plugs and a supporting structure with a specific spacing greater than the aperture of capacitor holes, preventing lateral deformation and short circuits while enhancing capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the capacitor size is continuously reduced to increase density, then the integration density is improved, but the stability of the capacitor structure deteriorates
Solution Approach 1:
The patent introduces a lateral supporting structure that extends from the substrate to support the capacitor laterally, adding a dimensional element perpendicular to the traditional vertical capacitor structure. This lateral support dimension prevents deformation without increasing the vertical footprint, thus maintaining high density while improving stability.
Solution Approach 2:
The supporting structure acts as an intermediary element between the substrate and the capacitor, providing mechanical support and preventing direct stress on the capacitor walls. This intermediary structure absorbs mechanical stress and prevents the capacitor from deforming, resolving the stability issue without affecting density.
2Quantity of substance
If the capacitor size is continuously reduced to increase density, then the integration density is improved, but the risk of short circuit increases
Solution Approach 1:
By adding lateral support structures that extend outward from the capacitor, the patent creates an additional dimensional barrier against short circuits. These supporting structures prevent lateral deformation that could cause adjacent capacitors to touch, thus reducing short circuit risk while maintaining high density.
Solution Approach 2:
The supporting structure is designed with a spacing greater than the capacitor hole aperture, creating a protective buffer zone before deformation can occur. This beforehand cushioning prevents the capacitor walls from collapsing inward or deforming laterally, thus preventing short circuits before they can happen.
3Reliability
If a supporting structure with spacing greater than capacitor hole aperture is used, then the stability and reliability are improved, but the device complexity increases
Solution Approach 1:
The supporting structure serves multiple functions simultaneously: it provides lateral support to prevent deformation, acts as a mechanical barrier against short circuits, and maintains the spacing between capacitors. This multi-functionality reduces the need for separate structures for each function, thus limiting the increase in complexity while achieving multiple reliability goals.
Solution Approach 2:
The supporting structure is strategically placed only where needed - at the lateral edges of the capacitor array - rather than uniformly throughout. This localized approach provides maximum stability support where deformation is most likely to occur while minimizing the overall structural complexity and material usage.
Data Source
AI summary
A semiconductor device and a forming method thereof are provided. The semiconductor device includes a substrate, a capacitor array and a supporting structure. A plurality of conductive contact plugs which are arranged at intervals are formed on the substrate. The capacitor array includes a plurality of columnar capacitors which are arranged at intervals. Each columnar capacitor is formed on a respective one of the conductive contact plugs. A lower electrode layer of the columnar capacitor is in contact connection with the conductive contact plug. The supporting structure is formed on the substrate at an edge of the capacitor array and surrounds the capacitor array. A spacing between an inner wall and an outer wall of the supporting structure on any cross section parallel to the substrate is greater than an aperture of a capacitor hole of any one of the columnar capacitors on the cross section.