Cup-Shaped DRAM Capacitor With Support Layers
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Solution Overview
Problem
Dynamic random access memory (DRAM) capacitors face challenges in increasing capacitance and mechanical strength due to high integration and density, making it difficult to enhance the capacitor area in the lateral direction, and existing manufacturing processes are complex and costly.
Innovation Solution
The capacitor design incorporates a reinforcement structure with multiple support layers and a cup-shaped lower electrode, eliminating the need for additional photomasks and chemical mechanical polishing, allowing for increased capacitance and mechanical strength while simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the capacitor area is increased in the lateral direction to increase capacitance, then the capacitance increases, but the integration density decreases and the memory cell area increases
Solution Approach 1:
The patent transitions from lateral area expansion to vertical height expansion by forming a cup-shaped lower electrode structure. The capacitive dielectric layer is deposited on the inner surface, outer surface, and bottom surface of the cup-shaped electrode, effectively utilizing three-dimensional space to increase capacitance without occupying additional lateral area, thereby maintaining high integration density while achieving higher capacitance values.
2Quantity of substance
If the capacitor area is increased to increase capacitance, then the capacitance increases, but the mechanical strength of the capacitor decreases
Solution Approach 1:
The cup-shaped lower electrode structure with capacitive dielectric layer deposited on inner surface, outer surface, and bottom surface creates a three-dimensional capacitive structure that increases capacitance without requiring lateral area expansion. This vertical configuration maintains structural integrity and mechanical strength while achieving higher capacitance through increased surface area in the vertical dimension.
3Manufacturing precision
If additional photomasks and chemical mechanical polishing processes are used to form the cup-shaped lower electrode, then the manufacturing precision increases, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent employs a self-aligned etching process where the mask layer automatically forms an overhang structure during deposition, eliminating the need for additional photomasks. The etching process uses this self-formed mask to create the cup-shaped lower electrode structure with high precision. This self-service approach achieves manufacturing precision comparable to multi-step photolithography processes while significantly reducing process complexity and manufacturing cost.
Data Source
AI summary
A capacitor and a manufacturing method thereof are provided. The capacitor includes a cup-shaped lower electrode, a capacitive dielectric layer, an upper electrode, and a support layer. The support layer includes an upper support layer surrounding an upper portion of the cup-shaped lower electrode, a middle support layer surrounding a middle portion of the cup-shaped lower electrode, and a lower support layer surrounding a lower portion of the cup-shaped lower electrode. Surfaces of the upper support layer, the middle support layer, and the lower support layer are covered by the capacitive dielectric layer.