MIM Capacitor High-k Low-k Dielectric Spacers Corner Charge
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Solution Overview
Problem
Existing processes for manufacturing metal-insulator-metal (MIM) capacitors are not entirely satisfactory as device scaling-down continues, particularly in preventing charge accumulation at corners of electrode layers, leading to reliability and leakage issues.
Innovation Solution
The formation of a metal-insulator-metal capacitor structure involves a dielectric composite structure with low-k dielectric spacers on the sidewalls of high-k dielectric layers, preventing charge concentration and enhancing film quality, allowing for thinner high-k layers without lowering breakdown voltage, achieved through specific layering and patterning processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing manufacturing processes are used for MIM capacitors, then manufacturing simplicity is maintained, but charge accumulation occurs at corners of electrode layers leading to reliability and leakage issues
Solution Approach 1:
The dielectric structure is segmented into multiple layers with different dielectric constants - a high-k dielectric layer (first dielectric layer) and a low-k dielectric layer (second dielectric layer). This segmentation prevents charge accumulation at the electrode corners by distributing the electric field more evenly, thereby improving capacitor reliability without significantly complicating the manufacturing process
Solution Approach 2:
Different regions of the dielectric structure are assigned different dielectric constants to address local charge accumulation problems. The high-k dielectric material is positioned where stronger electric field confinement is needed, while the low-k dielectric material is positioned at the corners and edges where charge accumulation occurs, creating local quality variations that prevent reliability issues
2Reliability
If high-k dielectric layer thickness is reduced to increase capacitance, then capacitance value increases, but breakdown voltage decreases
Solution Approach 1:
A composite dielectric structure is formed by combining high-k and low-k dielectric materials in specific configurations. The high-k dielectric layer provides high capacitance density, while the low-k dielectric layer (with dielectric constant less than 3.0) is positioned at regions prone to charge accumulation and field concentration. This composite structure enables the use of thinner high-k layers to achieve higher capacitance while the low-k layer maintains the breakdown voltage by preventing electric field concentration at critical locations
3Productivity
If device geometric size is reduced to increase functional density, then functional density increases, but charge accumulation at corners becomes more severe
Solution Approach 1:
As device dimensions are reduced to increase functional density, the corner effects become more pronounced. The invention applies local quality by positioning low-k dielectric material specifically at the corner regions and edges of the capacitor structure, where charge accumulation is most severe. This localized approach allows continued scaling for higher functional density while maintaining leakage resistance through targeted electric field management at critical geometric features
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach results in a MIM capacitor with high capacitance values while maintaining or improving breakdown voltage, effectively addressing reliability and leakage problems.
Implementation Method 1
a dielectric composite structure with low-k dielectric spacers on the sidewalls of high-k dielectric layers
Data Source
AI summary
A metal-insulator-metal (MIM) capacitor structure and a method for forming the same are provided. The MIM capacitor structure includes a first electrode layer formed over a substrate, and a first spacer formed on a sidewall of the first electrode layer. The MIM capacitor structure also includes a first dielectric layer formed on the first spacers, and an end of the first dielectric layer is in direct contact with the first pacer.