Semiconductor Substrate Processing for Barrier-Free Metal Film Deposition
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Solution Overview
Problem
In the manufacturing of semiconductor devices with three-dimensional structures, such as NAND flash memory, the thinning of word lines made of tungsten (W) film is challenging due to difficulties in etching as the number of layers increases, and there is a need for a method to form metal-based films with improved properties without using a barrier film like titanium nitride (TiN).
Innovation Solution
A technique involving the supply of a second-metal-containing gas to a substrate with a first metal film and insulating film to form films with improved properties, where the second metal is deposited on both the first metal film and the insulating film, using a substrate processing apparatus that controls gas flow and temperature to optimize film formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a barrier film (e.g., TiN) is used between the W film and insulating film, then the film properties and selectivity are improved, but the process complexity and number of layers increase
Solution Approach 1:
The patent removes the barrier film layer from the structure by using the insulating film itself as the barrier. The insulating film is treated with a specific gas (e.g., CF4, C4F8, or C2F6) to enhance its barrier properties, allowing it to prevent metal diffusion without requiring an additional TiN barrier layer.
Solution Approach 2:
The insulating film serves dual functions: as the insulating layer and as the barrier film. By treating the insulating film with fluorocarbon gas, it gains both insulating and barrier properties, eliminating the need for a separate barrier film layer.
2Length of moving object
If etching is performed to thin the W film, then the word line thickness is reduced, but etching becomes difficult as the number of layers increases
Solution Approach 1:
The patent changes the physical and chemical parameters of the insulating film surface by treating it with fluorocarbon gas. This treatment modifies the surface energy and composition, creating a barrier that prevents W film diffusion without requiring aggressive etching processes.
3Adaptability or versatility
If the number of layers is increased, then the three-dimensional structure is enhanced, but the thinning of word lines becomes more difficult
Solution Approach 1:
The patent applies local quality modification by treating only the insulating film surface with fluorocarbon gas. This creates a localized barrier property at the interface between the insulating film and W film, preventing diffusion at this specific location without affecting other parts of the structure.
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 method allows for the formation of metal-based films with enhanced properties, enabling better selectivity and uniformity in film deposition, particularly in three-dimensional structures, thereby addressing the challenges of etching and pattern preservation in semiconductor devices.
Implementation Method 1
supplying a second-metal-containing gas, which contains a second metal, to a substrate including a first metal film, which contains a first metal, and an insulating film to form a first film containing the second metal on the first metal film
Data Source
AI summary
According to one embodiment of the present disclosure, there is provided a technique that includes (a) supplying a second-metal-containing gas to a substrate including a first metal film and an insulating film to form a first film containing a second metal on the first metal film; and (b) supplying the second-metal-containing gas to the substrate to form a second film containing the second metal on the first film and the insulating film.