Interfacial Roughness Reducing Film for Semiconductor Wiring Reliability
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Solution Overview
Problem
The existing methods for forming wiring grooves in semiconductor devices, such as the damascene method, cause damage to the insulator film, leading to increased leakage current and degradation in Time-Dependent Dielectric Breakdown (TDDB) properties, especially when the distance between wiring lines is less than 0.1 μm, affecting the reliability and power consumption of semiconductor devices.
Innovation Solution
An interfacial roughness reducing film is applied, composed of silicon and oxygen or silicon and carbon, with a thickness of 0.1-50 nm, which is smoother than the insulator film, reducing the interfacial roughness between the wiring line and the insulator film, and is formed using organosilane compounds after surface roughening treatments like etching or CMP, to enhance TDDB resistance and reduce leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the damascene method is employed for forming wiring lines, then wiring lines can be formed in grooves, but the insulator film is damaged during etching, leading to increased leakage current and degradation in TDDB properties
Solution Approach 1:
A roughness reducing film is introduced as an intermediary layer between the insulator film and the wiring line. This film has a dual function: it absorbs the roughness from the insulator film surface (protecting the wiring line interface) while its top surface provides a smooth interface for the wiring line. This mediator layer decouples the damage caused during etching from the wiring line interface, thereby maintaining TDDB properties while still enabling wiring line formation.
Solution Approach 2:
The insulator film-wiring line interface is segmented by introducing a separate roughness reducing film layer. This segmentation allows the insulator film to have its rough surface (which is acceptable for the insulator function) while the wiring line interfaces with a separate film that provides the necessary smooth surface. The roughness reducing film thus separates the roughness generation from the roughness impact on wiring line performance.
2Area of moving object
If the distance between two wiring lines is reduced to increase integration density, then device miniaturization is achieved, but leakage current between wiring lines increases significantly
Solution Approach 1:
The roughness reducing film acts as a mediator that eliminates the roughness-induced leakage paths between closely spaced wiring lines. By providing a smooth interface between the insulator film and wiring line, and a smooth top surface for wiring line contact, it prevents field concentration at rough interfaces that would otherwise cause increased leakage current in densely packed wiring structures.
3Object-affected harmful factors
If surface treatment is applied to make grooves hydrophobic, then water adsorption is reduced and dielectric constant degradation is suppressed, but TDDB reliability is not sufficiently improved
Solution Approach 1:
The roughness reducing film is a more effective intermediary than hydrophobic treatment because it physically absorbs the roughness and provides a smooth interface. This structural solution directly addresses the root cause of TDDB degradation (interface roughness) rather than just mitigating secondary effects (water adsorption). The film's smooth top surface ensures good wiring line contact while its bottom surface absorbs insulator film roughness, providing comprehensive protection for TDDB reliability.
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 interfacial roughness reducing film effectively decreases leakage current and improves TDDB resistance, resulting in a highly reliable semiconductor device with reduced electric power consumption, particularly suitable for densely packed wiring structures.
Implementation Method 1
an interfacial roughness reducing film which is in contact with an insulator film and also in contact with a wiring line on the other side surface thereof, wherein the interfacial roughness between the wiring line and the interfacial roughness reducing film is smaller than that between the insulator film and the interfacial roughness reducing film
Data Source
AI summary
Techniques for obtaining a wiring layer with a high TDDB resistance and little leakage current, and accordingly, for manufacturing a highly reliable semiconductor device with a small electric power consumption are provided, in which an interfacial roughness reducing film is formed which is in contact with an insulator film and also in contact with a wiring line on the other side surface thereof, and has an interfacial roughness between the wiring line and the interfacial roughness reducing film smaller than that between the insulator film and the interfacial roughness reducing film.