MIM Capacitor Structure Using Self-Aligned Contacts
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Solution Overview
Problem
Conventional metal-insulator-metal (MIM) and metal-oxide-metal (MOM) capacitors in semiconductor devices require multiple process steps and masks, increasing manufacturing costs, and have low capacitance densities due to low dielectric constant materials between routing metallization layers.
Innovation Solution
A capacitor structure is developed using self-aligned contact technology and replacement metal gate technology, with wall spacers minimizing the distance between metal plates and efficient interconnections to increase capacitance density, incorporating high-k gate dielectric materials and non-oxide etch-stop structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional MIM or MOM capacitor fabrication processes are used, then the manufacturing process is well-established, but multiple process steps and masks are required increasing manufacturing cost
Solution Approach 1:
The patent combines capacitor formation with existing CMOS fabrication processes by utilizing the same deposition and etching steps for both transistor gates and capacitor dielectric layers. This merging of processes eliminates separate capacitor fabrication steps and masks, reducing manufacturing complexity and cost while maintaining established process compatibility
Solution Approach 2:
The fabrication process is designed to serve multiple functions: the same dielectric deposition creates both transistor gate insulation and capacitor dielectric layers, and the same etching processes define both transistor gates and capacitor structures. This multi-functionality reduces the number of dedicated process steps and masks required for capacitor fabrication
2Productivity
If conventional MOM capacitor structures are used, then the fabrication process is simpler, but low dielectric constant materials result in low capacitance densities
Solution Approach 1:
The patent changes the dielectric constant parameter by introducing high-k dielectric materials (such as barium strontium titanate or lead zirconate titanate) into the capacitor structure. These materials provide significantly higher capacitance density compared to conventional low-k silicon oxide, while the deposition processes are adapted to accommodate these advanced materials
Solution Approach 2:
The patent employs composite dielectric structures combining multiple materials with different properties. High-k dielectric layers are integrated with standard silicon oxide layers, creating a composite structure that achieves high capacitance density while maintaining compatibility with existing CMOS fabrication processes and providing appropriate electrical characteristics
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
The solution reduces manufacturing costs and enhances capacitance density by minimizing the distance between metal plates and improving interconnections, leading to more efficient semiconductor device performance.
Implementation Method 1
incorporating high-k gate dielectric materials
Implementation Method 2
Metal-insulator-metal (MIM) capacitors
Data Source
AI summary
A capacitor structure in a semiconductor device includes a semiconductor substrate having a top surface and a bottom surface opposite the top surface, an isolation region having a top surface and a bottom surface, opposite the top surface, the bottom surface of the isolation region being disposed on the top surface of the semiconductor substrate. The capacitor structure also includes a gate terminal structure disposed on the top surface of the isolation region and a diffusion contact structure disposed on the top surface of the isolation region and arranged parallel to the gate terminal structure. In some aspects, the gate terminal structure is connected to a first contact node and the diffusion contact structure is connected to a second contact node, in which the first and second contact nodes form opposing nodes of the capacitor structure.