Polyamine Passivation for Ge Substrate Post-CMP Cleaning
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Solution Overview
Problem
The miniaturization of integrated circuits and the need for higher driving current in transistors lead to challenges in maintaining surface smoothness and preventing corrosion of germanium (Ge) or silicon germanium (SiGe) containing regions during chemical mechanical polishing (CMP) processes, which negatively impact device performance and yield.
Innovation Solution
A cleaning composition containing an organic polyamine is used to form a passivation layer on Ge or SiGe fins, preventing oxidation and corrosion during post-CMP cleaning, and a wetting agent is included to improve surface cleanliness and prevent re-deposition of contaminants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional CMP cleaning is used on Ge-containing substrates, then cleaning efficiency is improved, but surface roughness increases and corrosion occurs
Solution Approach 1:
A polyamine-based passivation layer is introduced as an intermediary substance between the cleaning composition and the Ge-containing substrate. This passivation layer selectively adsorbs onto the Ge surface, forming a protective barrier that prevents direct contact between corrosive cleaning agents and the substrate, thereby maintaining surface smoothness while enabling effective cleaning
Solution Approach 2:
The cleaning composition parameters are modified by adjusting pH to specific ranges (e.g., pH 2-4 for acidic cleaners, pH 9-11 for alkaline cleaners) and controlling polyamine concentrations (e.g., 0.1-5% w/v). These parameter changes optimize the balance between cleaning efficiency and corrosion prevention, allowing effective contaminant removal while preserving surface integrity
2Shape
If CMP process is applied to Ge-containing regions, then surface planarity is improved, but oxidation and corrosion occur during post-CMP cleaning
Solution Approach 1:
The polyamine-based passivation layer is applied preliminarily before the cleaning process to pre-protect the Ge-containing substrate surface. This preliminary action of forming the passivation layer prevents oxidation and corrosion from occurring during the subsequent cleaning steps, ensuring reliability is maintained while achieving the desired surface planarity from CMP
Solution Approach 2:
The polyamine passivation layer creates an inert chemical environment on the Ge substrate surface by forming a protective barrier that excludes oxygen and moisture. This inert environment prevents oxidation reactions during post-CMP cleaning, allowing the substrate to maintain its corrosion resistance while achieving improved surface planarity
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 use of the polyamine-based cleaning composition enhances the surface smoothness and stability of Ge or SiGe-based FinFET devices, improving device performance and yield by reducing corrosion and surface roughness.
Implementation Method 1
The polyamine may be selectively adsorbed onto surfaces of Ge-containing fins
Implementation Method 2
The cleaning composition may include a wetting agent
Data Source
AI summary
A cleaning composition for cleaning a surface of a substrate comprising silicon germanium after a chemical mechanical polishing process is provided. The cleaning composition includes an oligomeric or polymeric polyamine, at least one wetting agent, a pH adjusting agent, and a solvent.