MIM Capacitor Layout for Etch-Tolerant Area Expansion
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Solution Overview
Problem
Existing Metal-Insulator-Metal (MIM) capacitor structures in semiconductor devices face challenges in maintaining effective area and process tolerance due to the need for dummy plates to address uneven etch loading, which reduces the capacitor's effective area.
Innovation Solution
The method involves implementing top-down enclosure of openings and replacing dummy plates in the bottom conductor plate layer with dummy plates in the top conductor plate layer, along with top-down enclosure of dummy plates, to increase the effective area of the MIM capacitor while maintaining process tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dummy plates are formed in each conductor plate layer to prevent etch loading, then process tolerance is improved, but the effective area of the MIM capacitor is reduced
Solution Approach 1:
The patent segments the dummy plate formation to specific conductor plate layers (bottom and middle layers) rather than forming dummy plates in all layers. This selective segmentation maintains process tolerance by addressing etch loading in critical layers while preserving effective area by eliminating dummy plates from the top conductor plate layer where they would not serve the etch loading function.
Solution Approach 2:
The patent extracts and removes the unnecessary dummy plates from the top conductor plate layer. By taking out these redundant structures, the effective area of the MIM capacitor is increased while the essential function of preventing etch loading is maintained through dummy plates in the bottom and middle layers.
2Reliability
If openings and dummy plates are formed in conductor plate layers to provide process tolerance, then manufacturing reliability is improved, but the capacitor capacitance is reduced
Solution Approach 1:
The patent applies local quality by differentiating the treatment of dummy plates across different conductor plate layers. The bottom and middle layers retain dummy plates for etch loading control, while the top layer has dummy plates removed. This localized differentiation maintains manufacturing reliability where needed while maximizing capacitance by reducing non-functional structures in the top layer.
Solution Approach 2:
The patent inverts the conventional approach by removing dummy plates from the top conductor plate layer instead of forming them in all layers. This inversion maintains process tolerance through dummy plates in lower layers while increasing capacitance by eliminating unnecessary structures in the top layer that would otherwise reduce the effective capacitive area.
Data Source
AI summary
Semiconductor devices, integrated circuits and methods of forming the same are provided. In one embodiment, a semiconductor device includes a metal-insulator-metal structure which includes a bottom conductor plate layer including a first opening and a second opening, a first dielectric layer over the bottom conductor plate layer, a middle conductor plate layer over the first dielectric layer and including a third opening, a first dummy plate disposed within the third opening, and a fourth opening, a second dielectric layer over the middle conductor plate layer, and a top conductor plate layer over the second dielectric layer and including a fifth opening, a second dummy plate disposed within the fifth opening, a sixth opening, and a third dummy plate disposed within the sixth opening. The first opening, the first dummy plate, and the second dummy plate are vertically aligned.