Semiconductor Wafer Treatment Liquid for Smooth Ruthenium Etching
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Solution Overview
Problem
Existing semiconductor wafer treatment liquids for etching ruthenium and other metals have high etching rates but struggle to control surface roughness effectively, leading to inadequate smoothness post-etching.
Innovation Solution
A semiconductor wafer treatment liquid comprising hypohalite ion and specific amounts of halate, halite, or halide ions, which allows for precise control of the etching rate and surface roughness by adjusting the anion species content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional treatment liquids with high oxidizing power are used, then etching rate is improved, but surface roughness increases
Solution Approach 1:
The patent applies parameter changes by carefully controlling the pH value within 2-12 and the oxidation-reduction potential within 50-800 mV, and by adjusting the concentrations of hypohalite ions (0.01-2 mol/L) and halide ions (0.1-5 mol/L). These parameter optimizations enable the treatment liquid to achieve both sufficient etching rate and smooth surface finish, resolving the contradiction between productivity and manufacturing precision
Solution Approach 2:
The patent uses a composite chemical system containing multiple ion species (hypohalite ions, halide ions, and optionally halate or halite ions) working together. This composite approach allows the treatment liquid to provide both the oxidizing power needed for etching and the surface-smoothing effect, simultaneously achieving high etching rate and low surface roughness
2Productivity
If strong oxidizing agents are used to increase etching rate, then productivity improves, but control precision over surface quality deteriorates
Solution Approach 1:
The patent optimizes the oxidation-reduction potential to a specific range of 50-800 mV, which is lower than conventional strong oxidizing agents. This parameter control enables sufficient etching rate while providing better control over surface smoothness, preventing excessive roughness formation
3Productivity
If pH is increased to enhance etching performance, then etching rate improves, but surface roughness increases
Solution Approach 1:
The patent optimizes pH to a specific range of 2-12, avoiding both extremely low and extremely high pH values. This parameter optimization enables the treatment liquid to achieve good etching performance while maintaining smooth surface finish, resolving the contradiction between etching rate and surface roughness
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 treatment liquid achieves a sufficient etching rate of 20 Å/min or less while effectively inhibiting surface roughness, making it suitable for the etch back process in semiconductor production.
Implementation Method 1
the treatment liquid includes at least one hypohalite ion and at least one anion species selected from halate ion, halite ion and halide ion
Implementation Method 2
at least one of the anion species has a content of 0.30 mol/L or more and 6.00 mol/L or less relative to the treatment liquid
Data Source
AI summary
The present invention provides a semiconductor wafer treatment liquid, the treatment liquid including at least one hypohalite ion, and at least one anion species selected from halate ion, halite ion and halide ion, wherein at least one of the anion species has a content of 0.30 mol/L or more and 6.00 mol/L or less relative to the treatment liquid.