Tantalum Etching Solution for Fast, Selective Semiconductor Processing

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Solution Overview

Problem

Existing etching solutions for semiconductor substrates with tantalum-containing layers lack sufficient etching speed and selectivity, particularly in the context of miniaturized wiring.

Innovation Solution

A processing solution comprising an oxidizing agent, a fluorine-based compound, an alkali metal compound, and/or an alkaline earth metal compound, along with water, is used to enhance the etching speed of tantalum-containing layers, with specific components and concentrations optimized for efficient etching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional etching solutions are used for tantalum-containing layers, then the process is simple and reliable, but the etching speed is insufficient for miniaturized wiring

Engineering Contradiction:
Improveetching speedVSAvoidsolution composition complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent changes the chemical parameters of the etching solution by incorporating specific oxidizing agents (iodine-containing compounds like iodine, iodic acid, or periodic acid), fluorine-based compounds (such as HF, NH4F, or hexafluorosilicic acid), and alkali/alkaline earth metal compounds (like KOH, NaOH, Ca(OH)2, or Mg(OH)2). This combination of specific chemical parameters achieves high etching speed for tantalum-containing layers while maintaining selectivity and minimizing damage to adjacent materials.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If higher etching speed is achieved for tantalum layers, then productivity improves, but selectivity and damage to adjacent materials may worsen

Engineering Contradiction:
Improveetching efficiencyVSAvoiddamage to adjacent materials
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The etching solution is designed to act selectively on tantalum-containing layers while being gentle on adjacent materials. The specific combination of oxidizing agents, fluorine-based compounds, and alkali/alkaline earth metal compounds creates a chemically selective environment that targets tantalum for rapid etching while minimizing harmful effects on surrounding structures through controlled chemical interactions.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses a composite chemical system combining multiple types of compounds (oxidizing agents, fluorine-based compounds, and alkali/alkaline earth metal compounds) that work synergistically. This composite solution provides both high etching speed for tantalum and selectivity to protect adjacent materials, achieving high productivity without excessive damage.

Inventive Principle:
Principle #40Composite materials

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 achieves high etching speed and selectivity for tantalum-containing layers while minimizing damage to adjacent materials like copper, thereby improving semiconductor manufacturing efficiency.

Implementation Method 1

a processing solution including an oxidizing agent, a fluorine-based compound, an alkali metal compound and/or an alkaline earth metal compound, and water

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 2

a processing solution including an oxidizing agent, a fluorine-based compound, an alkali metal compound and/or an alkaline earth metal compound, and water

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Data Source

PatentUS20250346811A1Processing solution, processing method of semiconductor substrate, and manufacturing method of semiconductor device
Publication Date: 2025.11.13 TOKYO OHKA KOGYO CO LTD

AI summary

There are provided a processing solution including an oxidizing agent, a fluorine-based compound, an alkali metal compound and/or an alkaline earth metal compound, and water; a processing method of a semiconductor substrate using the same; and a manufacturing method of a semiconductor device using the same.