Cerium Etching Solution for Ruthenium Removal on Substrates

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Solution Overview

Problem

The demand for effective removal of precious metals like ruthenium in semiconductor device manufacturing processes is not adequately met by existing solutions, which require improved etching performance.

Innovation Solution

A chemical solution comprising a cerium-containing oxidizing agent and an acid component, such as carbonic acid or its salts, is developed to enhance the removal of precious metals, including ruthenium, by dissolving these components in water and applying the solution to substrates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If existing etching solutions are used for precious metals like ruthenium, then the manufacturing process can proceed, but the etching rate and removal performance are insufficient

Engineering Contradiction:
Improveetching rateVSAvoidremoval performance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent changes the chemical parameters of the etching solution by selecting specific acids (carbonic acid, formic acid, propionic acid, butyric acid, or sulfonic acid and their salts) combined with cerium-containing oxidizing agents at controlled concentrations. This parameter optimization achieves both high etching rates and reliable removal performance for precious metals like ruthenium, resolving the contradiction between productivity and reliability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite chemical solution system combining cerium-containing oxidizing agents with specific organic acids or their salts. This composite formulation synergistically enhances the etching capability and removal performance for precious metals, simultaneously improving both etching rate and reliability without sacrificing either parameter.

Inventive Principle:
Principle #40Composite materials

2Reliability

If the chemical solution composition is optimized for better removal performance, then the etching effectiveness improves, but the solution formulation becomes more complex

Engineering Contradiction:
Improveremoval performanceVSAvoidsolution formulation
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent develops a universal etching solution formulation that effectively removes multiple precious metals (ruthenium, rhodium, platinum, palladium, iridium) using the same base composition of cerium-containing oxidizing agents combined with specific organic acids. This multi-functional solution achieves reliable removal performance across different metals without requiring separate complex formulations for each metal, thereby reducing overall solution formulation complexity while maintaining high reliability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 significantly improves the etching rate and removal performance of precious metals, as demonstrated by increased etching rates in experimental results, making it suitable for semiconductor device manufacturing.

Implementation Method 1

etching solutions containing orthoperiodic acid as an oxidizing agent have been proposed

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 2

a step for dissolving the cerium-containing oxidizing agent (A) and the acid component (B) in water

Methodology Applied
Scientific EffectDissolution: Solvation

Data Source

PatentUS20240191361A1Chemical solution for removing precious metal, method for manufacturing chemical solution, method for treating substrate, method for manufacturing semiconductor device
Publication Date: 2024.06.13 TOKYO OHKA KOGYO CO LTD

AI summary

A chemical solution for removing a precious metal includes a cerium-containing oxidizing agent (A), an acid component (B) selected from the group consisting of carbonic acid, formic acid, propionic acid, butyric acid, and sulfonic acid, and salts thereof, and water.