Surface Modification Layer for Low-k Dielectric Via Reliability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The scaling down of semiconductor integrated circuits leads to challenges such as increased dielectric layer damage during plasma processes, which results in carbon depletion and hydroxide group termination, increasing the dielectric constant (k-value) and causing resistance and reliability issues.
Innovation Solution
A surface modification layer formed from a phosphoric acid derivative is applied to the dielectric layer surfaces to repair damage, replenish carbon, and remove hydroxide groups, thereby reducing resistance and improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plasma processes are used for opening formation, then productivity is improved, but dielectric layer damage occurs causing carbon depletion and hydroxide group termination
Solution Approach 1:
A surface modification layer is formed on the dielectric layer surface before the plasma etching process. This pre-formed layer serves as a protective barrier that prevents plasma-induced damage, carbon depletion, and hydroxide group termination during the opening formation process, thereby maintaining dielectric layer integrity while enabling efficient plasma processing
Solution Approach 2:
The surface modification layer acts as an intermediary between the plasma process and the dielectric layer. It absorbs the harmful effects of plasma exposure (carbon depletion, hydroxide termination) while allowing the plasma process to proceed effectively for opening formation, thus protecting the underlying dielectric layer from direct damage
2Area of moving object
If geometry size is decreased for scaling down, then functional density is improved, but dielectric layer damage and resistance issues worsen
Solution Approach 1:
The surface modification layer is applied specifically to the regions where openings will be formed, providing localized protection and carbon replenishment exactly where plasma damage occurs during small geometry processing. This localized treatment addresses the specific needs of scaled-down features without affecting the entire dielectric layer
3Quantity of substance
If dielectric layer damage occurs, then carbon depletion increases, but this leads to increased k-value and resistance
Solution Approach 1:
The surface modification layer, formed through a controlled carbon-containing process, converts the harmful effect of plasma-induced carbon depletion into a benefit by providing a carbon-rich protective layer. This layer prevents further carbon loss during plasma etching and actually increases carbon content at the dielectric surface, thereby maintaining low k-value and reducing resistance in the resulting conductive features
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 surface modification layer reduces resistance, prevents conductive material extrusion, increases time-dependent dielectric breakdown failure times, and recovers dielectric k-value, enhancing wafer acceptance testing and yield.
Implementation Method 1
surfaces of the dielectric layer that define the opening are treated with a phosphoric acid derivative to form a surface modification layer
Data Source
AI summary
Embodiments described herein relate generally to methods for forming a conductive feature in a dielectric layer in semiconductor processing and structures formed thereby. In some embodiments, a structure includes a dielectric layer over a substrate, a surface modification layer, and a conductive feature. The dielectric layer has a sidewall. The surface modification layer is along the sidewall, and the surface modification layer includes phosphorous and carbon. The conductive feature is along the surface modification layer.