Stack Capacitor Vertical Electrode Alignment
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Solution Overview
Problem
The existing stack MIM capacitor structure in semiconductor devices faces issues with reduced fabrication efficiency and capacitance due to the need for multiple processes to align electrodes with different surface areas, leading to parasitic capacitance and oxidation at interfaces.
Innovation Solution
The solution involves arranging the electrodes of the first and second capacitors vertically to have the same surface area, reducing the number of fabrication processes and preventing capacitance deterioration by ensuring corresponding electrode areas through a method that includes forming a laminated structure with metal layers and dielectric layers, and using photolithography and etching techniques to achieve vertical alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If electrodes of different surface areas are used in stack capacitor structure, then capacitance capacity can be increased, but the number of fabrication processes increases and fabrication efficiency deteriorates
Solution Approach 1:
The patent applies asymmetry by intentionally designing electrodes with different surface areas within the same capacitor stack. The first electrode has a first surface area and the second electrode has a second surface area that is different from the first, allowing optimization of capacitance capacity while managing fabrication complexity through controlled asymmetric design.
Solution Approach 2:
The patent segments the capacitor structure into multiple layers with different electrode configurations. By dividing the capacitor into a first capacitor and a second capacitor with different electrode surface areas, the design achieves higher overall capacitance capacity while distributing the fabrication complexity across segmented structures.
2Manufacturing precision
If multiple masks are used to align electrodes with different surface areas, then electrode alignment can be achieved, but the number of fabrication processes increases
Solution Approach 1:
The patent applies preliminary action by pre-forming the first electrode with a specific surface area before forming the second electrode. This sequential approach with pre-planned electrode dimensions enables precise alignment and different surface areas to be achieved while minimizing the number of additional masking processes required.
Solution Approach 2:
The patent resolves alignment complexity by transitioning from two-dimensional planar alignment to three-dimensional vertical stacking. By forming electrodes at different vertical levels with different surface areas, the design achieves precise alignment through vertical dimension control rather than relying solely on multiple lateral masking processes.
Data Source
AI summary
A stack capacitor in a semiconductor device includes a first capacitor formed on and/or over a semiconductor substrate and a second capacitor formed on and/or over the first capacitor. The first and second capacitors each have a multi-layer laminated structure which includes a lower electrode, a capacitor dielectric layer and an upper electrode. At least two of the lower electrodes and the upper electrodes are arranged vertically with respect to each other to have the same width and/or surface area.