Low-k Dielectric Etching Protection via Sacrificial Layer
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Solution Overview
Problem
Low-k dielectric materials used in semiconductor devices are susceptible to damage during etching processes, leading to higher leakage currents, lower breakdown voltages, and changes in dielectric constant, which affects the yield, performance, and reliability of integrated circuit devices.
Innovation Solution
A method for forming an interconnect structure that involves using a sacrificial layer, a dielectric hard mask layer, and a low-k dielectric material, with the inclusion of a barrier layer and air gaps to protect the low-k dielectric material during processing, and a chemical mechanical polishing process to refine the structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If low-k dielectric materials are used to reduce RC delay, then circuit performance is improved, but the dielectric material becomes susceptible to damage during etching processes
Solution Approach 1:
A sacrificial layer is introduced as an intermediary between the etching process and the low-k dielectric material. This sacrificial layer absorbs the etching damage that would otherwise directly affect the low-k dielectric, allowing the etching to proceed while protecting the underlying dielectric material from harmful effects
Solution Approach 2:
The sacrificial layer is deposited and patterned before the low-k dielectric material is formed. This preliminary structure is specifically designed to protect the low-k dielectric during subsequent etching operations, preventing damage before it can occur to the critical dielectric layer
2Ease of manufacture
If conventional etching processes are used on low-k dielectric materials, then manufacturing simplicity is maintained, but leakage currents increase and breakdown voltages decrease
Solution Approach 1:
The sacrificial layer serves as a protective intermediary during the etching process, allowing conventional etching techniques to be used while preventing the harmful effects (increased leakage current and decreased breakdown voltage) that would normally result from direct etching of the low-k dielectric material
Solution Approach 2:
The harmful etching effects are extracted or isolated to the sacrificial layer, which is designed to be removed after serving its protective function. This separates the damaging etching action from the low-k dielectric material, allowing the dielectric to maintain its electrical properties
3Reliability
If the sacrificial layer is removed to expose the low-k dielectric, then the protective function is achieved, but the low-k dielectric becomes exposed to potential damage
Solution Approach 1:
The sacrificial layer is selectively removed after it has fulfilled its protective role during etching. By extracting this temporary protective structure, the low-k dielectric is revealed while having already been protected from the harmful etching effects, thus achieving both protection and exposure of the dielectric
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 effectively reduces damage to low-k dielectric materials during etching, enhancing the yield, performance, and reliability of integrated circuit devices by minimizing leakage currents and maintaining dielectric integrity.
Implementation Method 1
a chemical mechanical polishing process to refine the structure
Data Source
AI summary
The present disclosure, in some embodiments, relates to an interconnect structure. The interconnect structure has a metal body disposed over a substrate, and a metal projection protruding outward from an upper surface of the metal body. A dielectric layer is disposed over the substrate and surrounds the metal body and the metal projection. A barrier layer separates the metal body and the metal projection from the dielectric layer.