Remote Plasma Source for Substrate Pre-treatment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Plasma processing in semiconductor fabrication often damages porous low-k dielectric materials and fails to effectively protect refractory metal layers due to high-energy ion bombardment and inadequate barrier formation, particularly in the case of copper metallization and dual-damascene structures.
Innovation Solution
A plasma processing chamber equipped with a remote plasma source that generates neutral hydrogen and oxygen radicals, which are filtered to prevent ion acceleration and facilitate soft etching and oxidation, forming a hydroxide film to protect refractory metals and improve barrier integrity in low-k dielectric materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional plasma processing is used for pre-cleaning and oxidation, then processing speed is improved, but damage to porous low-k dielectric materials and refractory metal layers increases due to high-energy ion bombardment
Solution Approach 1:
A remote plasma source is introduced as an intermediary component that generates plasma away from the substrate and transports reactive species to the processing chamber. This mediator approach allows plasma generation without direct ion bombardment of the substrate, reducing damage while maintaining processing effectiveness
Solution Approach 2:
The harmful ion bombardment component is extracted and separated from the useful reactive species. The remote plasma source generates plasma, but only neutral radicals are transported to the substrate through a differentially pumped chamber, leaving behind the damaging ions while retaining the beneficial chemical reactivity
2Reliability
If conventional plasma processing is used, then barrier formation is achieved, but the barrier integrity and protection against metal diffusion into low-k dielectric is insufficient
Solution Approach 1:
The plasma processing parameters are fundamentally changed by using a remote plasma source that delivers neutral radicals instead of ionized plasma. This parameter change enables gentler chemistry that forms more uniform and intact barrier layers without the mechanical damage of ion bombardment, improving both barrier formation and integrity
Solution Approach 2:
The remote plasma source performs preliminary treatment of the substrate surface by delivering reactive neutral species that prepare the surface for subsequent barrier deposition. This preliminary action includes gentle oxidation and cleaning that creates an ideal surface state for barrier formation without compromising the underlying low-k dielectric 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
The solution effectively reduces damage to low-k dielectric materials, enhances barrier formation, and improves the conductivity and reliability of metal films by using neutral radicals for pre-cleaning and oxidation, thereby increasing the throughput and reducing heat load and ion bombardment-related issues.
Implementation Method 1
A plasma processing chamber equipped with a remote plasma source that generates neutral hydrogen and oxygen radicals
Implementation Method 2
which are filtered to prevent ion acceleration and facilitate soft etching and oxidation
Implementation Method 3
forming a hydroxide film to protect refractory metals and improve barrier integrity in low-k dielectric materials
Data Source
AI summary
A plasma processing chamber particularly useful for pre-treating low-k dielectric films and refractory metal films subject to oxidation prior to deposition of other layers. A remote plasma source (RPS) excites a processing gas into a plasma and delivers it through a supply tube to a manifold in back of a showerhead faceplate. The chamber is configured for oxidizing and reducing plasmas in the same or different processes when oxygen and hydrogen are selectively supplied to the RPS. The supply tube and showerhead may be formed of dielectric oxides which may be passivated by a water vapor plasma from the remote plasma source. In one novel process, a protective hydroxide coating is formed on refractory metals by alternating neutral plasmas of hydrogen and oxygen.