Tungsten Hexacarbonyl Solid Source for Corrosion-Free CVD
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Solution Overview
Problem
Conventional tungsten hexafluoride sources for metallization in large-scale integrated circuits suffer from interfacial silicon consumption and corrosion due to hydrogen fluoride byproducts, necessitating the development of alternative tungsten solid source materials with improved volatilization, transport, and deposition properties for CVD and ALD processes.
Innovation Solution
A solid source material based on tungsten hexacarbonyl with a molybdenum content less than 1000 ppm, processed by sintering particulate tungsten hexacarbonyl at temperatures below 100°C to produce a sintered solid source material with controlled particle size distribution, enhancing consistent delivery and gas-phase concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tungsten hexafluoride is used as the source reagent, then tungsten deposition can be achieved, but hydrogen fluoride byproducts cause interfacial silicon consumption and corrosion of microelectronic devices
Solution Approach 1:
The patent extracts and removes the harmful fluorine element from the tungsten source reagent, replacing WF6 with W(CO)6. This substitution eliminates the generation of hydrogen fluoride byproducts that cause corrosion, while maintaining the ability to deposit tungsten films through carbonyl-based chemistry
Solution Approach 2:
The patent changes the chemical composition parameters of the source reagent from fluoride-based (WF6) to carbonyl-based (W(CO)6). This parameter change fundamentally alters the decomposition pathway, producing non-corrosive byproducts while maintaining effective tungsten deposition capability
2Manufacturing precision
If solid source materials are used for ALD and CVD processes, then improved deposition control is achieved, but particle size, surface area, and purity variations impact source material performance and process repeatability
Solution Approach 1:
The patent applies preliminary sintering treatment to the particulate tungsten hexacarbonyl raw material at temperatures below 100°C before use. This pre-treatment step consolidates the particles into a sintered solid with controlled surface area and porosity, ensuring consistent volatilization behavior and source material delivery across multiple process runs
Solution Approach 2:
The patent carefully controls the sintering temperature parameter (keeping it below 100°C) to avoid decomposition of the thermally sensitive tungsten hexacarbonyl while still achieving particle consolidation. This precise parameter control enables the formation of a stable sintered solid that maintains reproducible deposition characteristics
3Object-affected harmful factors
If high purity tungsten hexacarbonyl is used, then corrosion risks are reduced, but maintaining purity below 1000 ppm molybdenum requires stringent raw material selection
Solution Approach 1:
The patent implements preliminary purification steps in the material selection and preparation process to ensure molybdenum content remains below 1000 ppm. This pre-cleaning approach prevents contaminant buildup that could lead to corrosion, while establishing a quality baseline before the sintering and deposition processes
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 tungsten hexacarbonyl solid source material provides stable and repeatable tungsten-containing film deposition, reducing corrosion risks and improving process reliability in microelectronic device metallization, while maintaining high purity and efficient vaporization properties.
Implementation Method 1
volatilizing a solid source material of the present disclosure, to form a tungsten precursor vapor
Implementation Method 2
contacting the tungsten precursor vapor with a substrate under vapor deposition conditions, to form the tungsten-containing film on the substrate
Implementation Method 3
sintering the particulate tungsten hexacarbonyl raw material at temperature below 100° C. to produce the solid source material for forming a tungsten-containing film, as a sintered solid
Data Source
AI summary
A solid source material is described for forming a tungsten-containing film. The solid source material is tungsten hexacarbonyl, wherein content of molybdenum is less than 1000 ppm. Such solid source material may be formed by a process including provision of particulate tungsten hexacarbonyl raw material of particles of size less than 5 mm, wherein particles of size greater than 1.4 mm are less than 15% of the particles, and wherein content of molybdenum is less than 1000 ppm, and sintering the particulate tungsten hexacarbonyl raw material at temperature below 100° C. to produce the solid source material as a sintered solid.