DRAM Capacitor Electrode Support via Segmented Vertical Patterns
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Solution Overview
Problem
The miniaturization of DRAM capacitors leads to technical issues such as leaning or bending of lower electrodes during fabrication, which affects the capacitance and reliability of semiconductor devices.
Innovation Solution
A semiconductor device with a multi-layered supporting pattern that includes a lower and upper support pattern, where the upper support pattern has varying thickness and the lower support pattern has a constant thickness, both spaced apart to prevent leaning or bending of capacitor lower electrodes, and are formed without additional photolithography processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the capacitor lower electrodes are lengthened in the vertical direction to maintain adequate capacitance during miniaturization, then the capacitance is maintained, but leaning or bending of the lower electrodes occurs during fabrication
Solution Approach 1:
The supporting structure is divided into multiple layers (first supporting pattern and second supporting pattern) positioned at different vertical levels. This segmentation provides distributed support along the length of the lower electrode, preventing leaning or bending while maintaining the electrode's vertical extension for adequate capacitance
Solution Approach 2:
The solution transitions from a single-plane support structure to a multi-layered three-dimensional supporting pattern. By adding the vertical dimension with multiple supporting layers at different heights, the structure gains enhanced mechanical stability to prevent electrode deformation during fabrication
2Reliability
If additional photolithography processes are used to create supporting patterns, then the lower electrodes can be supported, but the manufacturing complexity and process time increase
Solution Approach 1:
The formation of multiple supporting patterns is merged into a single photolithography process step. All supporting patterns are formed simultaneously using one photolithography operation, eliminating the need for additional separate photolithography processes and reducing manufacturing complexity
Solution Approach 2:
The supporting patterns serve multiple functions: they provide mechanical support to prevent electrode leaning, define the geometric structure of the capacitor, and act as etch masks during fabrication. This multi-functionality reduces the need for separate dedicated support structures and processes
Data Source
AI summary
A semiconductor device includes a substrate and a plurality of storage nodes on the substrate and extending in a vertical direction relative to the substrate. A lower support pattern is in contact with the storage nodes between a bottom and a top of the storage nodes, the lower support pattern spaced apart from the substrate in the vertical direction, and the lower support pattern having a first maximum thickness in the vertical direction. An upper support pattern is in contact with the storage nodes above the lower support pattern relative to the substrate, the upper support pattern spaced apart from the lower support pattern in the vertical direction, and the lower support pattern having a second maximum thickness in the vertical direction that is greater than the first maximum thickness of the lower support pattern.