Ru/W Selective Etching Composition Using Periodic Acid and Benzotriazole
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current removal compositions for ruthenium (Ru) are inadequate in selectively removing Ru from substrates containing both Ru and tungsten (W) without corroding W, necessitating an improvement in etching processes for semiconductor applications.
Innovation Solution
A composition comprising periodic acid or its salt, a quaternary ammonium salt, and a nitrogen-containing resin is used, which selectively etches Ru by suppressing W etching, thereby enhancing Ru removability with improved Ru/W selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional removal composition is used to remove Ru from a substrate containing both Ru and W, then Ru removal is achieved, but W is also corroded due to insufficient selectivity
Solution Approach 1:
The patent modifies the chemical composition parameters by incorporating specific additives (benzotriazole or imidazole derivatives) alongside periodic acid and quaternary ammonium salts. These additives change the chemical reactivity parameters of the etching solution, enabling selective attack on Ru while suppressing reaction with W, thereby achieving Ru/W selectivity without causing W corrosion
Solution Approach 2:
The patent creates a composite chemical composition by combining multiple components: periodic acid (oxidizing agent), quaternary ammonium salt (surfactant/wetting agent), and benzotriazole or imidazole derivative (selectivity-enhancing additive). This composite formulation works synergistically to achieve selective Ru removal while protecting W from corrosion
2Productivity
If the etching process is made more aggressive to improve Ru removal rate, then productivity increases, but selectivity between Ru and W deteriorates
Solution Approach 1:
The benzotriazole or imidazole derivative acts as a selective intermediary that preferentially adsorbs onto W surfaces, forming a protective layer that mediates between the aggressive periodic acid and the W substrate. This allows the etching process to proceed at high rates on Ru while the intermediary protects W, thereby maintaining both high productivity and selectivity
Solution Approach 2:
The patent optimizes the concentration parameters of each component in the composition, particularly the ratio of periodic acid to quaternary ammonium salt to benzotriazole/imidazole derivative. By carefully controlling these parameters, the solution achieves optimal balance between etching aggressiveness (for high Ru removal rate) and selectivity (to protect W)
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 composition effectively removes Ru from substrates containing both Ru and W, ensuring selective etching and maintaining the integrity of W, thus improving the precision and efficiency of semiconductor processing.
Implementation Method 1
a composition comprising: periodic acid or a salt thereof
Implementation Method 2
a quaternary ammonium salt
Data Source
AI summary
An object of the present invention is to provide a composition having excellent ruthenium removability with respect to tungsten in a case of being applied to an object to be treated containing tungsten and ruthenium. The composition according to an embodiment of the present invention includes: periodic acid or a salt thereof, a quaternary ammonium salt; a resin containing a nitrogen atom; and a solvent.