Post-CMP Cleaning Liquid for Abrasive Particle Removal on Metal Films
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Solution Overview
Problem
Existing semiconductor substrate cleaning methods after chemical mechanical polishing (CMP) are inadequate in effectively removing abrasive particles from metal films, leading to potential short-circuits and adverse electrical properties.
Innovation Solution
A cleaning method using a cleaning liquid with a pH of more than 7, containing a chelating agent, a specific amine compound, and an anticorrosive, which adjusts surface contact angles and agglomeration to enhance abrasive particle removal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cleaning methods are used after CMP, then the cleaning process is simple, but abrasive particles remain on metal films causing short-circuits and poor electrical properties
Solution Approach 1:
The patent changes the chemical parameters of the cleaning liquid by specifying precise pH ranges (7.0-13.0), particular chelating agents (EDTA, DTPA, NTA), and amine compound types with specific pKa values. These parameter changes enable effective abrasive particle removal while maintaining metal film integrity, directly improving electrical properties without excessive complexity
Solution Approach 2:
The cleaning liquid employs a composite formulation combining multiple functional components: chelating agents for metal ion complexation, amine compounds for surface interaction and particle detachment, and anticorrosive agents for metal film protection. This composite approach achieves superior cleaning efficacy and reliability
2Reliability
If stronger cleaning agents are used to remove abrasive particles, then particle removal performance improves, but metal films may be damaged or corroded
Solution Approach 1:
The cleaning liquid exhibits local quality by targeting abrasive particles and organic residues specifically through chelating agents that bind metal ions and amine compounds that interact with organic materials, while the anticorrosive agents locally protect the metal film surface. This selective action achieves high particle removal performance without damaging the metal film
Solution Approach 2:
The chelating agents and amine compounds act as intermediaries that facilitate the removal of abrasive particles bound to metal films. These intermediaries complex with metal ions and interact with particle surfaces, enabling particle detachment without direct harsh chemical attack on the metal film, thus preserving film integrity while improving removal performance
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 method effectively prevents abrasive particles from adhering to metal films, improving the removal of residues and ensuring better electrical performance of semiconductor substrates.
Implementation Method 1
the cleaning liquid comprises: a chelating agent
Implementation Method 2
a component A that is at least one selected from the group consisting of a primary amine, a secondary amine, and a tertiary amine
Implementation Method 3
an anticorrosive
Data Source
AI summary
An object of the invention is to provide a method of cleaning semiconductor substrates that is excellent in abrasive particle removing performance with respect to semiconductor substrates having undergone CMP, as well as a cleaning liquid for semiconductor substrates having undergone CMP. The invention provides a method of cleaning semiconductor substrates, the method comprising a cleaning step of cleaning, by use of a cleaning liquid, a semiconductor substrate having undergone CMP using a polishing liquid containing abrasive particles. The semiconductor substrate contains metal, and the cleaning liquid has a pH of more than 7 at 25° C. The cleaning liquid comprises: a chelating agent; a specific component A; and an anticorrosive. The method satisfies Condition 1 that a product of a contact angle ratio obtained by a specific test method 1 and a specific degree of agglomeration obtained by a specific test method 2 is not more than 15.