Multilayer MIM Capacitor Electrodes for Lower Series Resistance
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Solution Overview
Problem
Metal-Insulator-Metal (MIM) capacitors in semiconductor integrated circuits face challenges in achieving low time constants due to the relatively low conductivity of their conductor plate layers, which limits their suitability for high-frequency applications.
Innovation Solution
The implementation of multilayer conductor plate layers, where a metal layer is sandwiched between two metal nitride layers, utilizing the same metal target for both nitride and metal layers, such as titanium or tantalum, to enhance conductivity while maintaining oxidation protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal nitride layers are used as conductor plate layers in MIM capacitors, then oxidation protection is improved, but electrical conductivity deteriorates
Solution Approach 1:
The conductor plate layer is segmented into multiple thin layers alternating between metal nitride and metal materials. This segmentation allows each layer to perform its specialized function: metal nitride layers provide oxidation protection while metal layers provide high conductivity, resolving the contradiction between protection and conductivity.
Solution Approach 2:
The invention uses composite conductor plate structures combining metal nitride and metal materials in an interleaved configuration. This composite approach integrates the oxidiation resistance of metal nitrides with the high conductivity of metals, achieving both protection and low energy loss simultaneously.
2Loss of energy
If metal layers are used to improve conductivity, then electrical conductivity is improved, but oxidation resistance deteriorates
Solution Approach 1:
The conductor plate is divided into alternating segments of metal and metal nitride layers. The metal segments provide high conductivity while the metal nitride segments provide oxidation protection, allowing the metal to function without direct oxygen exposure.
Solution Approach 2:
Metal nitride layers act as intermediary barrier layers between the metal conductor layers and the oxygen-containing environment. These intermediary layers prevent direct contact between oxygen and metal, protecting the metal from oxidation while allowing electrical conduction through the metal layers.
3Loss of time
If series resistance is reduced for high-frequency applications, then time constant is improved, but material conductivity requirements increase
Solution Approach 1:
The conductor plate is segmented into multiple thin alternating layers of metal and metal nitride. The cumulative effect of multiple high-conductivity metal layers reduces overall series resistance and time constant, while the interspersed nitride layers maintain oxidation protection throughout the structure.
Data Source
AI summary
Semiconductor devices and methods of forming the same are provided. In one embodiment, a semiconductor device includes a contact feature in a first dielectric layer, a first passivation layer over the contact feature, a bottom conductor plate layer disposed over the first passivation layer and including a first plurality of sublayers, a second dielectric layer over the bottom conductor plate layer, a middle conductor plate layer disposed over the second dielectric layer and including a second plurality of sublayers, a third dielectric layer over the middle conductor plate layer, a top conductor plate layer disposed over the third dielectric layer and including a third plurality of sublayers, and a second passivation layer over the top conductor plate layer.