Semiconductor Wiring Air Gap Formation with Diffusion Barriers
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Solution Overview
Problem
The miniaturization of semiconductor devices leads to increased electric capacity between wirings, causing signal degradation due to high permittivity, and existing air gap structures face challenges with processing accuracy and misalignment, resulting in degraded circuit characteristics.
Innovation Solution
A method involving the formation of a substrate with a first and second diffusion barrier film to suppress copper diffusion, combined with an air gap structure between copper-containing films, using specific films like SiON and SiOC, and a substrate processing apparatus to ensure precise formation of these films and air gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If an air gap structure is formed by etching between wirings to reduce permittivity, then the signal speed is improved, but misalignment occurs due to processing accuracy issues, causing degradation of circuit characteristics
Solution Approach 1:
The patent forms diffusion barrier films on the copper-containing films before etching the air gap. This preliminary action prevents copper diffusion that would occur during the subsequent etching process, thereby maintaining manufacturing precision while still allowing the air gap to be formed for signal speed improvement.
Solution Approach 2:
The diffusion barrier film acts as an intermediary layer between the copper-containing films and the etching process. It mediates the conflict by preventing harmful copper diffusion during etching, allowing the air gap structure to be formed without degrading circuit characteristics due to misalignment.
2Productivity
If the space between wirings is miniaturized to achieve high integration, then the device density is improved, but the electric capacity between wirings increases, causing signal degradation
Solution Approach 1:
The patent introduces air gaps (voids) between the miniaturized wirings, creating a porous-like structure with low permittivity. This allows the wiring space to be efficiently utilized for high integration while the air gaps reduce electric capacity between adjacent wirings, maintaining signal speed despite miniaturization.
3Reliability
If a diffusion barrier film is formed on copper-containing films to suppress copper diffusion, then the reliability is improved, but the device complexity increases due to additional film formation steps
Solution Approach 1:
The patent forms diffusion barrier films selectively on specific portions of the copper-containing films, particularly on the upper surfaces that are exposed during air gap formation. This local application approach maintains reliability by preventing copper diffusion where it would cause misalignment, while avoiding unnecessary complexity by not applying barriers to all surfaces.
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 effectively reduces permittivity between wirings, enhancing signal speed and maintaining circuit characteristics by preventing copper diffusion and ensuring accurate air gap formation, thus improving semiconductor device performance.
Implementation Method 1
a first diffusion barrier film formed on a portion of an upper surface of the copper-containing films to suppress diffusion of a component of the copper-containing films
Data Source
AI summary
A method of manufacturing a semiconductor device includes loading, into a process chamber, a substrate including a first wiring layer having a first interlayer insulating film, a plurality of copper-containing films formed on the first interlayer insulating film and used as a wiring, an inter-wiring insulating film insulating between the plurality of copper-containing films, and a void formed between the plurality of copper-containing films, and a first diffusion barrier film formed on a portion of an upper surface of the copper-containing films to suppress diffusion of a component of the copper-containing films, and forming a second diffusion barrier film configured to suppress diffusion of a component of the copper-containing films on a surface of another portion, on which the first diffusion barrier film is not formed, in the copper-containing films.