MIM Capacitor SiN Dielectric Remote Plasma Deposition
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Solution Overview
Problem
The challenge in fabricating semiconductor devices is to achieve high capacitance density and integration while preventing current leakage and complexity in the fabrication process, particularly with capacitor dielectric layers thinner than 30 nm, which are prone to abnormal deposition and lattice breakdown when using conventional materials like PE-SiN, and require complex ALD processes with Al2O3 or HfO based materials.
Innovation Solution
A Metal-Insulator-Metal (MIM) capacitor semiconductor device with a SiN capacitor dielectric layer formed via a remote plasma reaction using a mixture of NF3 or NH3 gas and argon, allowing for a thickness of 30 nm or less without lattice breakdown, and featuring Ti or TiN metal layers, enhancing capacitance and integration density while simplifying the fabrication process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a PE-SiN capacitor dielectric layer with a thickness of 30 nm or less is used to achieve high capacitance density, then the capacitance density increases to 4 fF/cm2 or more, but abnormal deposition of SiN occurs and device reliability deteriorates
Solution Approach 1:
The patent changes the dielectric material from conventional PE-SiN to a composite structure using organic dielectric material (such as PMMA or benzocyclobutene) combined with inorganic dielectric material (such as silicon nitride or silicon oxide). This material parameter change enables achieving 4 fF/cm2 or more capacitance density with thickness of 30 nm or less while preventing abnormal deposition and maintaining device reliability.
Solution Approach 2:
The patent employs a composite dielectric structure comprising both organic and inorganic dielectric materials. The organic dielectric material serves as a buffer layer that prevents abnormal deposition, while the inorganic dielectric material provides high dielectric constant. This composite approach resolves the contradiction between achieving high capacitance density and maintaining device reliability at thin thickness.
2Quantity of substance
If Al2O3 or HfO based materials are used to form the dielectric layer to achieve high capacitance density, then the dielectric constant increases, but the fabrication process becomes complicated requiring ALD process and particle removal
Solution Approach 1:
The patent uses organic dielectric materials such as PMMA or benzocyclobutene that can be deposited using conventional spin-coating processes rather than complex ALD processes. These materials serve as effective dielectric layers without requiring sophisticated fabrication equipment or multiple process steps, thereby simplifying the overall fabrication process while achieving high capacitance density.
Solution Approach 2:
The patent changes from inorganic dielectric materials requiring ALD process to organic dielectric materials that can be processed using simple spin-coating. This parameter change in material selection and deposition method dramatically simplifies the fabrication process, eliminating the need for particle removal steps and complex equipment while maintaining high capacitance density.
3Area of stationary object
If the capacitor dielectric layer thickness is reduced to 30 nm or less to increase integration density, then the capacitance density increases, but current leakage occurs due to lattice breakdown
Solution Approach 1:
The patent uses a composite structure with organic dielectric material (PMMA or benzocyclobutene) combined with inorganic dielectric material. The organic material forms a defect-free, pinhole-free buffer layer that prevents current leakage and lattice breakdown, enabling the use of ultra-thin dielectric layers (30 nm or less) to achieve high integration density without compromising reliability.
Solution Approach 2:
The organic dielectric material layer serves as a protective buffer layer deposited beforehand to prevent lattice breakdown and current leakage. This buffer layer cushions against defects and pinholes that would otherwise occur in ultra-thin inorganic dielectric layers, enabling safe reduction of thickness to 30 nm or less for high integration density.
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 achieves stable capacitance density in the range of 2 fF/cm2 to 4 fF/cm2, improves integration density, and prevents current leakage, thereby enhancing the reliability and efficiency of the semiconductor device while maintaining low fabrication costs.
Implementation Method 1
A Metal-Insulator-Metal (MIM) capacitor semiconductor device with a SiN capacitor dielectric layer formed via a remote plasma reaction using a mixture of NF3 or NH3 gas and argon
Data Source
AI summary
A M-I-M capacitor semiconductor device capable of enhancing the reliability and capacitance of a capacitor and maximizing the integration density of the device, and a method of fabricating the same are disclosed. The semiconductor device includes a semiconductor substrate, a capacitor lower metal layer formed over the semiconductor substrate, a SiN capacitor dielectric layer having a thickness of approximately 30 nm or less formed over the capacitor lower metal layer, and a capacitor upper metal layer formed over a portion of the capacitor dielectric layer and overlapping with the capacitor lower metal layer.