Iodine Boron Cleaning Agent for Tantalum Nitride Residue Removal

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Solution Overview

Problem

Current cleaning agents are ineffective in selectively removing tantalum nitride etching mask residues during dual damascene processing of integrated circuits, affecting the cleaning efficiency and requiring a solution that is compatible with Cu, Co, Ta, W, Ti, and low-k materials.

Innovation Solution

A cleaning agent composed of 0.5%-20% oxidant containing iodine, 0.5%-20% etchant containing boron, 1%-50% pyrrolidinone solvent, 1%-20% corrosion inhibitor, and 0.01%-5% metal ion-free surfactant, with a pH of 7.5-13.5, specifically designed to efficiently remove nitride hard mask residues while minimizing impact on metal and low-k dielectric materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional cleaning agents are used to remove etching mask residues, then cleaning process is simple, but they cannot effectively remove tantalum nitride etching mask residues

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidcleaning agent formulation complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The cleaning agent uses a composite formulation combining iodine-containing oxidants (iodine, iodic acid, iodic acid, periodic acid, periodate), boron-containing etchants (boric acid, boric anhydride, tetrafluoroboric acid, ammonium tetrafluoroborate), and pyrrolidinone solvents (N-methylpyrrolidinone, N-ethylpyrrolidinone, N-cyclohexylpyrrolidinone, N-hydroxyethylpyrrolidinone) in specific proportions to achieve effective removal of tantalum nitride residues while maintaining selectivity

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The cleaning agent optimizes specific parameter ranges: iodine-containing oxidant (0.5-20%), boron-containing etchant (0.5-20%), pyrrolidinone solvent (1-50%), corrosion inhibitor (1-20%), and surfactant (0.01-5%), with pH controlled at 7.5-13.5, to achieve the breakthrough in removing TaN residues

Inventive Principle:
Principle #35Parameter changes

2Reliability

If cleaning agent strength is increased to remove tantalum nitride residues, then cleaning effectiveness improves, but damage to metal and low-k dielectric materials increases

Engineering Contradiction:
Improveresidue removal effectivenessVSAvoiddamage to metal and low-k materials
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The cleaning agent exhibits selective action with different effectiveness on different materials: it strongly attacks tantalum nitride residues while having minimal effect on metal interconnects (Cu, Co, Ta, W, Ti) and low-k dielectric materials, achieving local quality in cleaning effectiveness

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The pyrrolidinone solvent acts as an intermediary that facilitates the selective removal of tantalum nitride residues while protecting other materials, and the corrosion inhibitor serves as a mediator to further reduce damage to sensitive metal and dielectric structures

Inventive Principle:
Principle #24Intermediary (Mediator)

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 cleaning agent effectively removes nitride residues with high selectivity, improving the cleaning process and having a broad market application prospect, particularly in microelectronics, enhancing production efficiency and equipment reliability.

Implementation Method 1

0.5%-20% of an oxidant containing iodine

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 2

0.5%-20% of an etchant containing boron

Methodology Applied
Scientific EffectChemical etching: Chemical Bonding

Data Source

PatentUS11549086B2Cleaning agent and preparation method and use thereof
Publication Date: 2023.01.10 SHANGHAI SINYANG SEMICONDUCTOR MATERIALS CO LTD

AI summary

Provided are a cleaning agent and a preparation method and the use thereof. The cleaning agent is prepared from the following raw materials comprising the following mass fraction of components: 0.5%-20% of an oxidant containing iodine, 0.5%-20% of an etchant containing boron, 1%-50% of a pyrrolidinone solvent, 1%-20% of a corrosion inhibitor, 0.01%-5% of a metal ion-free surfactant, and water, with the sum of the mass fraction of each component being 100%, the pH of the cleaning agent is 7.5-13.5, and the corrosion inhibitor is one or more of a benzotriazole corrosion inhibitor, a hydrazone corrosion inhibitor, a carbazone corrosion inhibitor and a thiocarbohydrazone corrosion inhibitor. The cleaning agent can efficiently remove nitrides from hard mask residues with little effects on metals and low-κ dielectric materials, and has a good selectivity.