Cleaning Liquid for Semiconductor Substrate RuO2 Selectivity
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Solution Overview
Problem
Current cleaning solutions for semiconductor substrates after chemical mechanical polishing (CMP) treatments lack effective selectivity in removing RuO2 residues while minimizing the removal of Ru wiring lines, leading to suboptimal electrical characteristics.
Innovation Solution
A cleaning liquid comprising perhalogen acids, halogen acids, and optional components such as organic base compounds, organic acids, anticorrosive agents, and surfactants, with specific pH and composition ranges, is used to enhance the selectivity of RuO2 removal without significantly affecting Ru wiring lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional cleaning solutions are used to remove RuO2 residues after CMP, then RuO2 removal speed is maintained, but Ru wiring line removal also occurs leading to poor electrical characteristics
Solution Approach 1:
The patent applies parameter changes by carefully controlling the pH value (2.0-12.0) and the mass ratio of perhalogen acid to halogen acid (0.00001-50) to achieve selective removal of RuO2 while preserving Ru wiring lines. This optimization of chemical parameters enables differential reactivity between RuO2 and Ru, resolving the contradiction between removal efficiency and selectivity
Solution Approach 2:
The cleaning liquid uses a composite acid system combining perhalogen acid (such as periodic acid) and halogen acid (such as iodic acid) in specific ratios. This composite formulation creates synergistic effects where the perhalogen acid provides strong oxidizing power for RuO2 removal while the halogen acid modulates the overall selectivity, preventing Ru wiring line damage
2Productivity
If strong oxidizing agents are used to increase RuO2 removal speed, then cleaning efficiency improves, but damage to Ru wiring lines increases
Solution Approach 1:
The patent controls the oxidizing strength by adjusting the concentration and type of perhalogen acid and halogen acid, maintaining an optimal balance between RuO2 removal speed and Ru wiring line preservation through precise parameter optimization
Solution Approach 2:
The halogen acid acts as an intermediary that moderates the strong oxidizing action of perhalogen acid. It provides a buffering effect that enables sustained RuO2 removal while protecting Ru wiring lines from excessive oxidation damage
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 proposed cleaning liquid improves the selectivity for RuO2 removal, ensuring high removal performance while maintaining the integrity of Ru wiring lines, thereby enhancing the electrical characteristics of semiconductor substrates.
Implementation Method 1
a cleaning liquid comprising: a perhalogen acid; and a halogen acid
Data Source
AI summary
The present invention provides a cleaning liquid for a semiconductor substrate that has been subjected to CMP, in which the cleaning liquid has an excellent selectivity for RuO2 removing performance; and a method for cleaning a semiconductor substrate that has been subjected to CMP. The cleaning liquid of an embodiment of the present invention is a cleaning liquid for a semiconductor substrate that has been subjected to a chemical mechanical polishing treatment, in which the cleaning liquid includes a perhalogen acid and a halogen acid.