Double-Sided Capacitor Structure for Stable High-Aspect DRAM Electrodes
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Solution Overview
Problem
The miniaturization of semiconductor devices leads to lateral instability and increased risk of collapse or overturning of capacitor electrodes in DRAM structures, limiting capacitance value and performance reliability.
Innovation Solution
A double-sided capacitor structure is formed by alternately stacking sacrificial and supporting layers in a substrate, filling capacitor holes with conductive material, and selectively removing layers to enhance electrode stability and capacitance, including steps of forming electrode and dielectric layers and conductive filling within the capacitor holes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the height of the bottom electrode is increased to maintain capacitance value during miniaturization, then the capacitance value is maintained, but the aspect ratio increases and lateral stability deteriorates
Solution Approach 1:
The single supporting layer is segmented into multiple supporting layers separated by sacrificial layers. This segmentation allows the electrode structure to be divided into multiple stable segments, each supported by its own supporting layer, thereby maintaining lateral stability while achieving greater overall height and capacitance value.
Solution Approach 2:
The solution transitions from a single-layer supporting structure to a multi-layer stacked structure in the vertical dimension. By adding the vertical stacking of supporting and sacrificial layers, the structure achieves both increased height (for capacitance) and maintained lateral stability through distributed support points.
2Area of stationary object
If the thickness of the bottom electrode is reduced to achieve miniaturization, then the lateral area is reduced, but the electrode becomes thinner and more prone to collapse
Solution Approach 1:
The electrode structure is segmented vertically into multiple sections, each with its own supporting layer. This segmentation provides distributed mechanical support along the height of the thin electrode, preventing collapse while maintaining the reduced lateral dimensions required for miniaturization.
Solution Approach 2:
The patent employs thin supporting layers and sacrificial layers that provide mechanical reinforcement to the thin electrode structure. These thin film structures enable the electrode to maintain strength despite reduced thickness, allowing miniaturization without sacrificing structural integrity.
3Stability of the object's composition
If a single lateral supporting layer is added to improve stability, then the stability is improved, but the height limit is reached and capacitance value is limited
Solution Approach 1:
The single supporting layer is segmented into multiple supporting layers separated by sacrificial layers. This segmentation allows the electrode structure to be divided into multiple stable segments, each supported by its own supporting layer, thereby maintaining lateral stability while achieving greater overall height and capacitance value.
Solution Approach 2:
The solution transitions from a single-layer supporting structure to a multi-layer stacked structure in the vertical dimension. By adding the vertical stacking of supporting and sacrificial layers, the structure achieves both increased height (for capacitance) and maintained lateral stability through distributed support points.
Data Source
AI summary
A double-sided capacitor structure and a method for forming the same are provided. The method includes: providing a base including a substrate, capacitor contacts in the substrate, a stacked structure on a surface of the substrate, and capacitor holes penetrating through the stacked structure and exposing the capacitor contacts, and the stacked structure includes sacrificial layers and supporting layers which are alternately stacked in a direction perpendicular to the substrate; forming a first electrode layer, a first dielectric layer and a second electrode layer on inner walls of the capacitor holes; filling the capacitor holes with a first conductive material to form a first conductive filling layer; completely removing several of the sacrificial layers and/or the supporting layers to remain at least two of the supporting layers; and forming a second dielectric layer and a third electrode layer that covers a surface of the second dielectric layer.