Stepped Bottom Electrode Structure for Higher Capacitor Density
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Solution Overview
Problem
The manufacturing and integration of semiconductor devices face complexity issues, leading to deficiencies in performance and efficiency, particularly in the integration of electrodes within a limited footprint area.
Innovation Solution
A semiconductor device design featuring a bottom electrode structure with step-shaped sidewalls and a top electrode structure laterally surrounding it, separated by a high-k dielectric structure, which increases the effective capacitor area and capacitance per unit area through a specific layering and etching process involving different metal materials and dielectric layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If multiple metal layers are stacked to form the bottom electrode structure, then the effective area of the capacitor is increased, but the manufacturing complexity increases
Solution Approach 1:
The bottom electrode structure is segmented into multiple metal layers (first through fifth metal layers) with alternating materials, where each layer has a progressively smaller width. This segmentation creates a step-shaped cross-section that increases the effective capacitor area while maintaining manufacturability through systematic layering
Solution Approach 2:
The patent transitions from a two-dimensional planar electrode to a three-dimensional stepped structure by varying the width of each successive metal layer. This dimensional change increases the effective capacitor area without proportionally increasing the footprint, resolving the contradiction between area and complexity
2Quantity of substance
If the bottom electrode structure uses a step-shaped sidewall configuration, then the capacitance per unit area is enhanced, but the etching process complexity increases
Solution Approach 1:
The etching process is applied periodically and selectively to specific metal layers (second and fourth layers removed) while preserving others, creating the step-shaped profile through repeated cycles of selective removal rather than a single complex etching step
Solution Approach 2:
Different metal layers are assigned different local qualities through selective etching - the second and fourth layers are removed to create steps, while the first, third, and fifth layers remain to form the capacitor structure, optimizing both capacitance and manufacturability
Data Source
AI summary
A semiconductor device includes a bottom electrode structure disposed over a semiconductor substrate. The bottom electrode structure includes a first metal layer, a second metal layer, a third metal layer, a fourth metal layer, and a fifth metal layer from bottom to top. The first metal layer, the third metal layer and the fifth metal layer include a first metal material, and the second metal layer and the fourth metal layer include a second metal material different from the first metal material. The semiconductor device also includes a high-k dielectric structure disposed on opposite sidewalls of the bottom electrode structure. The opposite sidewalls of the bottom electrode structure are step-shaped. The semiconductor device further includes a top electrode structure laterally surrounding the bottom electrode structure and separated from the bottom electrode structure by the high-k dielectric structure.