Residue-Removing Solution for Semiconductor Copper Surface Protection

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current residue-removing solutions for semiconductor devices after dry etching processes fail to effectively prevent copper surface cracking, roughness, and oxidation, leading to defective devices and environmental concerns due to poor degradability of used chemicals.

Innovation Solution

A chemical solution with a pH of 4 to 9, containing specific Cu surface protective agents that form complexes with copper, selected from heteroaromatic and heterocyclic compounds, and water, which prevents copper surface cracking and oxidation while being environmentally friendly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional polymer-removing solutions are used to remove residues after dry etching, then residues are removed, but copper surface cracking and roughness occur

Engineering Contradiction:
Improvedevice yieldVSAvoidcopper surface quality
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the chemical parameters of the residue-removing solution by using a neutral or weakly basic pH range (7-14) instead of conventional acidic solutions, and by selecting specific base types (alkali metal hydroxides, alkaline earth metal hydroxides, or ammonia) to achieve effective residue removal while preventing copper surface cracking and roughness

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs environmentally friendly, easily degradable chemicals (common bases like NaOH, KOH, Ca(OH)2, or ammonia) that can be disposed of without causing environmental pollution, replacing conventional harmful chemical solutions

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Manufacturing precision

If sulfur-containing compounds are added to prevent copper cracking, then cracking is prevented, but copper discoloration occurs

Engineering Contradiction:
Improvecopper surface integrityVSAvoidaesthetic quality
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent extracts and eliminates sulfur-containing compounds from the chemical solution formulation, replacing them with sulfur-free base chemicals that prevent copper cracking through different mechanisms (pH control and surface passivation) without causing discoloration

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent achieves the protective function of sulfur-containing compounds (crack prevention) through alternative chemical mechanisms using bases that form protective layers on copper surfaces without the harmful side effects of sulfur compounds

Inventive Principle:
Principle #26Copying

3Reliability

If argon sputtering is used to remove copper oxide films, then oxide films are removed, but copper surface damage increases

Engineering Contradiction:
Improveelectrical conductivityVSAvoidcopper surface quality
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical/physical sputtering process with a chemical solution-based approach that uses neutral or weakly basic chemicals to selectively remove copper oxide films through chemical reaction, avoiding the mechanical damage inherent in sputtering

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the chemical environment from oxidizing (air exposure) to reducing/neutral (immersion in basic solution), preventing oxide formation and enabling gentle oxide removal through chemical dissolution rather than physical sputtering

Inventive Principle:
Principle #35Parameter changes

4Productivity

If conventional chemical solutions are used for residue removal, then residues are removed, but environmental pollution occurs due to poor degradability

Engineering Contradiction:
Improveresidue removal efficiencyVSAvoidenvironmental pollution
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent employs easily degradable, environmentally friendly chemicals (common bases like NaOH, KOH, Ca(OH)2, or ammonia) that break down naturally without persisting in the environment, replacing conventional harmful chemical solutions with poor degradability

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent converts potentially harmful strong bases into beneficial cleaning agents by controlling their concentration and exposure time, achieving effective residue removal while the bases decompose into harmless substances (water, carbon dioxide, salts) that benefit the environment

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 effectively removes residues, prevents copper surface damage, and enhances semiconductor device yield by preventing cracking and oxidation, while being environmentally friendly and reducing manufacturing costs.

Implementation Method 1

containing a Cu surface protective agent... which prevents copper surface cracking and oxidation

Methodology Applied
Scientific EffectComplex formation: Chemical Bonding

Implementation Method 2

A residue-removing solution for removing residues formed during dry etching and/or ashing

Methodology Applied
Scientific EffectChemical dissolution: Solvation

Data Source

PatentUS8822396B2Solution for removing residue after semiconductor dry process and method of removing the residue using the same
Publication Date: 2014.09.02 DAIKIN INDUSTRIES LTD

AI summary

A residue-removing solution for removing residues present on semiconductor substrates after dry etching and/or ashing, the residue-removing solution comprising a Cu surface protective agent including: at least one compound selected from compounds (1), (2) and (3) each having as a basic skeleton a five-membered or six-membered heteratomic structure as defined herein; a compound capable of forming a complex or chelate with Cu (copper); and water. Further, the residue-removing solution has a pH of 4 to 9.