DRAM Capacitor Structure With Seam Sealing to Reduce Leakage
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Solution Overview
Problem
The shrinking size of semiconductor structures in DRAM devices leads to increased leakage and manufacturing difficulties due to close component distances, affecting process yield and resistance values.
Innovation Solution
A method is introduced to form a semiconductor structure with a sealing layer in the seam of the conductive layer, oxidizing and removing excess material to create a bowl-shaped opening, and depositing additional conductive layers to improve adhesion and prevent oxidation, resulting in a capacitor structure without seams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the pitch between semiconductor structures is shortened to increase integration, then device density is improved, but leakage increases and manufacturing difficulty increases
Solution Approach 1:
The conductive layer is segmented into multiple sections with seams between them. The sealing layer is selectively formed at these seam locations to prevent leakage, while the capacitor structures between seams remain isolated. This segmentation approach allows close spacing for high density while maintaining reliability through localized sealing at critical seam points.
2Reliability
If the conductive layer is made continuous to improve conductivity, then electrical connection is improved, but seams are formed causing leakage
Solution Approach 1:
The sealing layer acts as an intermediary element between the conductive layer seams and the capacitor structures. It fills and seals the seam regions, preventing leakage while allowing the conductive layer to maintain its continuous structure for electrical connection. The sealing layer mediates between the need for continuity and the harmful effect of seams.
3Reliability
If additional layers are deposited to seal seams and prevent oxidation, then reliability is improved, but device complexity increases
Solution Approach 1:
The sealing layer is formed with local quality - it is selectively deposited only at the seam locations and inner sidewalls of capacitor structures, not uniformly across the entire surface. This localized approach provides the necessary sealing and oxidation protection exactly where needed, while minimizing the overall complexity and material usage compared to a complete uniform coating.
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 method reduces resistance and prevents oxidation, enhancing the process yield and performance of semiconductor structures by improving the adhesion and coverage of conductive layers.
Implementation Method 1
The sealing layer is oxidized by an asher oxidation process
Implementation Method 2
The oxidized sealing layer is removed by a dilute HF clean process
Data Source
AI summary
Embodiments of this disclosure provide a semiconductor structure, including a substrate, a lower electrode layer on the substrate, a first dielectric layer on the lower electrode layer and capacitor structures in the first dielectric layer and the second dielectric layer and each of the plurality of capacitor structures includes a sealing layer in an upper portion of each of the capacitor structures, a first conductive layer surrounding a sidewall and a bottom surface of the sealing layer, a top capacitor plate surrounding a sidewall and a bottom surface of the first conductive layer, an oxide layer surrounding a sidewall and a bottom surface of the top capacitor plate and a bottom capacitor plate on the lower electrode layer and surrounding a sidewall and a bottom surface of the oxide layer. In addition, a method of manufacturing a semiconductor structure is also disclosed in this disclosure.