Rounded-Corner MIM Capacitor Plates to Prevent Stress Cracking
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Solution Overview
Problem
As IC devices are scaled down, MIM capacitors become susceptible to cracking due to induced stress from surrounding layers and features, leading to performance degradation and manufacturing defects.
Innovation Solution
The formation of MIM capacitors with conductor plate layers having rounded corners, achieved through processes like photolithography and etching, mitigates stress accumulation and prevents cracking by distributing stress across a larger area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If MIM capacitors are scaled down to reduce IC dimensions and improve production efficiency, then manufacturing cost decreases and production efficiency improves, but the MIM capacitors become susceptible to cracking due to stress concentration
Solution Approach 1:
The patent applies curvature by rounding the corners of conductor plate layers in MIM capacitors. This geometric modification eliminates sharp corners that concentrate stress, thereby preventing cracking while maintaining the scaled-down dimensions needed for high productivity
2Volume of moving object
If MIM capacitors are scaled down to meet demand for smaller electronic devices, then device size decreases and more functions can be integrated, but stress-induced cracking increases leading to manufacturing defects
Solution Approach 1:
Rounding the corners of conductor plate layers transforms sharp geometric features into curved ones, distributing stress evenly across the structure. This prevents cracking and reduces manufacturing defects, thereby improving manufacturing precision while maintaining small device size
3Device complexity
If conventional fabrication processes are used for MIM capacitors with sharp corners, then manufacturing process complexity remains low, but stress concentration at corners causes cracking and performance degradation
Solution Approach 1:
The patent modifies the geometric shape of conductor plate layers by rounding corners, which can be integrated into existing fabrication processes through photolithography and etching. This approach maintains relatively low fabrication complexity while dramatically improving capacitor reliability by preventing stress-induced cracking
Data Source
AI summary
A metal-insulator-metal (MIM) structure and methods of forming the same for reducing the accumulation of external stress at the corners of the conductor layers are disclosed herein. An exemplary device includes a substrate that includes an active semiconductor device. A stack of dielectric layers is disposed over the substrate. A lower contact is disposed over the stack of dielectric layers. A passivation layer is disposed over the lower contact. A MIM structure is disposed over the passivation layer, the MIM structure including a first conductor layer, a second conductor layer disposed over the first conductor layer, and a third conductor layer disposed over the second conductor layer. A first insulator layer is disposed between the first conductor layer and the second conductor layer. A second insulator layer is disposed between the second conductor layer and the third conductor layer. One or more corners of the third conductor layer are rounded.