FinFET Gate Oxide Processing to Prevent Interfacial Layer Loss
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Solution Overview
Problem
The use of silicon dioxide as a gate dielectric in semiconductor devices leads to increased leakage currents and reduced reliability due to the thinning of the gate dielectric film with scaling, necessitating the adoption of high-κ dielectric films, but water-soluble interfacial layers are prone to loss during wet oxidation and photoresist stripping processes, affecting device performance.
Innovation Solution
Employing a non-aqueous solvent-based chemical for both wet oxidation and photoresist stripping processes to minimize interfacial layer loss, thereby reducing charge/trap density in the high-κ dielectric film and maintaining a smoother surface, while also reducing manufacturing costs and processing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a water-soluble interfacial layer is used to improve interface quality and reduce defects, then device performance stability is improved, but the interfacial layer is lost during wet oxidation and photoresist stripping processes, leading to increased charge/trap density and threshold voltage shift
Solution Approach 1:
The patent changes the chemical composition parameter of the interfacial layer from water-soluble materials (such as silicon oxide) to non-aqueous solvent-based materials (such as silicon nitride or silicon oxynitride). This parameter change allows the interfacial layer to maintain its function of improving interface quality and reducing defects while being resistant to loss during wet oxidation and photoresist stripping processes, thereby resolving the contradiction between reliability improvement and material loss.
2Loss of energy
If high-κ dielectric films are adopted to reduce leakage currents in scaled devices, then power consumption is reduced, but charge/trap density in the dielectric film increases when water-soluble interfacial layers are used
Solution Approach 1:
The patent changes the material parameter of the interfacial layer to non-aqueous solvent-based materials that are resistant to wet oxidation and photoresist stripping. This prevents interfacial layer loss that would otherwise expose the high-κ dielectric film to damage, thereby reducing charge/trap density in the dielectric film while maintaining the low leakage current benefit of high-κ materials.
Solution Approach 2:
The non-aqueous solvent-based interfacial layer acts as a protective intermediary between the substrate and the high-κ dielectric film. It prevents direct exposure of the high-κ dielectric to wet oxidation and photoresist stripping processes, thereby protecting the dielectric film from generating charges/traps while allowing the high-κ material to function in reducing leakage currents.
3Ease of manufacture
If conventional wet oxidation and photoresist stripping processes are used, then manufacturing simplicity is maintained, but interfacial layer loss occurs, affecting device performance
Solution Approach 1:
The patent changes the chemical resistance parameter of the interfacial layer by using non-aqueous solvent-based materials instead of water-soluble materials. This parameter change allows the interfacial layer to withstand conventional wet oxidation and photoresist stripping processes without loss, thereby maintaining both manufacturing simplicity and interfacial layer integrity simultaneously.
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 fewer charges/traps in the high-κ dielectric film, a smaller threshold voltage shift, and improved device reliability by maintaining a stable interfacial layer, leading to enhanced semiconductor device performance and reduced power consumption.
Implementation Method 1
a non-aqueous solvent-based chemical is used for both wet oxidation and photoresist stripping processes
Implementation Method 2
a non-aqueous solvent-based chemical is used for both wet oxidation and photoresist stripping processes
Data Source
AI summary
A semiconductor integrated circuit (IC) including a first fin structure having a first aqueous soluble channel layer. The semiconductor IC includes a first gate structure over the first aqueous soluble channel layer, wherein the first gate structure includes a first oxide film directly contacting the first aqueous soluble channel layer, and the first oxide film includes a first material. The semiconductor IC includes a first spacer along the first gate structure, wherein a bottom surface of the first spacer is above an interface between the first oxide layer and the first aqueous soluble channel layer. The semiconductor IC includes a second fin structure having a second aqueous soluble channel layer. The semiconductor IC includes a second gate structure over the second aqueous channel layer, wherein the second gate structure includes a second oxide film directly contacting the second aqueous soluble channel layer, the second oxide film includes a second material.