MIM Capacitor Contact Openings That Eliminate Corner Stress
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Solution Overview
Problem
MIM capacitors in semiconductor manufacturing face challenges with stress concentration at the corners of contact slots, leading to potential shorts, failures, and reduced reliability due to metal stress changes and adhesion weaknesses between metal and high-k insulator dielectric.
Innovation Solution
The formation of non-rectangular contact slots in MIM capacitors, such as open windows and corner openings in both inner and outer plates, reduces stress concentration by eliminating the highest stress locations, thereby improving the reliability of the structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional rectangular contact slots are used in MIM capacitors, then manufacturing is simpler, but stress concentration at corners causes shorts and failures
Solution Approach 1:
The patent extracts the problematic corner regions from the rectangular contact slot by creating openings at the corners. This removes the stress concentration points that cause adhesion failures and shorts, directly improving capacitor reliability while maintaining manufacturing feasibility
Solution Approach 2:
The patent transitions from sharp rectangular corners to curved or opened corner configurations. By replacing the 90-degree corners with curved edges or openings, the design eliminates stress concentration points, reducing adhesion failures and improving capacitor yield
2Area of stationary object
If metal plates extend to all corners of contact slots, then capacitor area is maximized, but stress-induced adhesion weakness occurs
Solution Approach 1:
The patent extracts metal plate material from the corner regions of contact slots, creating openings where the metal would otherwise extend to the corners. This removes the source of stress concentration while preserving the main capacitor area, maintaining capacitance while improving adhesion strength
Solution Approach 2:
The patent applies different structural qualities to different regions: the central contact slot area maintains full metal coverage for maximum capacitance, while the corner regions have openings or reduced metal presence to eliminate stress concentration. This local differentiation optimizes both area and adhesion strength
Data Source
AI summary
A semiconductor device including a metal insulator metal capacitor (MIM capacitor) within back end of line circuitry of the semiconductor device, and an outer plate contact opening of an outer plate of the MIM capacitor, wherein a portion of an inner plate is removed, where portions of the outer plate are removed from corners of the outer plate opening. A metal insulator metal capacitor (MIM capacitor) within back end of line circuitry of the semiconductor device, and a non-rectangular contact opening of an outer plate of the MIM capacitor. Forming a metal insulator metal capacitor (MIM capacitor) within back end of line circuitry of the semiconductor device, and an outer plate contact opening of an outer plate of the MIM capacitor, where a portion of an inner plate is removed, where portions of the outer plate are removed from corners of the outer plate opening.