Nested Crown Capacitor Structure to Prevent DRAM Process Damage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The fabrication of crown capacitors for DRAM is challenging due to their fragility, which causes them to bend or fall during processing, leading to potential short circuits and device failure, and there is a need for increased uniform capacitance while reducing susceptibility to process damage.
Innovation Solution
A U-shaped bottom electrode with a cap dielectric at its open end and a top electrode, along with a capacitor dielectric layer interposed between the bottom and top electrodes, forming an outer capacitor around a cylinder-type solid inner capacitor, which are fabricated separately to prevent bending and falling during processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the crown capacitor size is reduced to maximize charge storing capacity, then the capacitance efficiency is improved, but the structural strength deteriorates causing the capacitor to bend or fall during fabrication
Solution Approach 1:
The capacitor structure is segmented into an inner capacitor and an outer capacitor that are fabricated separately. The inner capacitor provides structural support while the outer capacitor provides capacitance. This segmentation allows each component to be optimized independently, solving the contradiction between small size and structural strength.
Solution Approach 2:
The inner capacitor is nested within the outer capacitor structure. The inner capacitor serves as a structural core that supports the overall architecture, while the outer capacitor provides the additional surface area needed for high capacitance. This nested configuration resolves the strength-capacitance contradiction.
2Area of stationary object
If the bottom electrode is made thinner to reduce capacitor footprint, then the device density is improved, but the reliability deteriorates due to increased susceptibility to damage
Solution Approach 1:
The bottom electrode is segmented into an inner bottom electrode and an outer bottom electrode. The inner bottom electrode can be made thinner to reduce footprint, while the outer bottom electrode provides additional mechanical support and damage resistance, maintaining reliability despite reduced overall device size.
3Productivity
If the crown capacitor dimensions are reduced to increase capacitance density, then the charge storing capacity is improved, but the manufacturing precision requirement increases due to fragility
Solution Approach 1:
The inner capacitor is fabricated first to establish a robust structural foundation before the outer capacitor is added. This preliminary action creates a stable platform that reduces the precision requirements for subsequent fabrication steps, enabling high capacitance density without excessive manufacturing difficulty.
Data Source
AI summary
This invention provides a capacitor structure includes a U-shaped bottom electrode having a cap dielectric provided at its open end, a top electrode and a capacitor dielectric layer interposed between the bottom electrode and the top electrode to constitute an outer capacitor around a cylinder type solid inner capacitor, and the outer capacitor and the inner capacitor are divided by the cap dielectric. The cylinder type solid inner capacitor and the outer capacitor are fabricated separately so that the cylinder type solid inner capacitor may support its own weight to prevent its structure from being damaged during the fabrication of the capacitor.