Semiconductor Substrate Cleaning Liquid Mixed Acid Composition
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Solution Overview
Problem
Current cleaning liquids for semiconductor substrates fail to simultaneously remove silica particles, alumina particles, and silicon nitride particles without etching the substrate and suppressing metal and organic component adsorption during the FEOL process in semiconductor fabrication.
Innovation Solution
A cleaning liquid composition comprising a compound with at least two sulfonic acid groups per molecule, such as phytic acid or a condensed phosphoric acid compound, combined with an inorganic acid like hydrochloric acid, and ozone water or hydrogen peroxide, which effectively removes particles and metals without etching the substrate, and further reduces organic component adsorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cleaning liquids (SC-1, SC-2, RCA) are used to remove particles and metals, then cleaning effectiveness is improved, but substrate etching increases and manufacturing precision deteriorates
Solution Approach 1:
The invention changes the chemical parameters of the cleaning liquid by using a mixed acid system (sulfuric acid + nitric acid) with specific concentration ratios, replacing conventional alkaline or single-acid systems. This parameter change enables effective particle and metal removal while controlling substrate etching to ≤0.1 nm, resolving the contradiction between cleaning effectiveness and manufacturing precision
Solution Approach 2:
The invention employs a composite cleaning liquid formulation combining sulfuric acid and nitric acid in specific proportions, along with hydrogen peroxide and surfactants. This composite approach synergistically enhances particle removal, metal dissolution, and organic substance oxidation while maintaining controlled etching, thereby improving reliability without sacrificing manufacturing precision
2Reliability
If multiple cleaning steps are implemented to remove all microparticles, organic substances, and metals, then cleaning completeness is improved, but process complexity increases
Solution Approach 1:
The mixed acid cleaning liquid performs multiple functions simultaneously: removing microparticles through acid etching, dissolving metals through chelation, and oxidizing organic substances through nitric acid and hydrogen peroxide. This multi-functional single-step process replaces conventional multi-step sequences (SC-1→SC-2→RCA), reducing process complexity while maintaining cleaning completeness
Solution Approach 2:
The invention merges particle removal, metal dissolution, and organic substance removal into a single integrated cleaning step using the mixed acid formulation. By combining functions that were previously performed in separate sequential steps, the process complexity is reduced while achieving comprehensive cleaning of all contamination types
3Manufacturing precision
If ammonia concentration and cleaning temperature are reduced to suppress substrate etching, then manufacturing precision is improved, but cleaning effectiveness deteriorates
Solution Approach 1:
The invention changes the chemical composition parameters by introducing a mixed acid system (sulfuric acid + nitric acid) with optimized concentration ratios, replacing the ammonia-based alkaline system. This parameter change enables effective particle removal through acid etching mechanisms while inherently controlling substrate damage, improving manufacturing precision without sacrificing cleaning effectiveness
Solution Approach 2:
The invention substitutes the alkaline chemical mechanism (ammonia-based) with an acidic chemical mechanism (sulfuric acid + nitric acid). This substitution changes the fundamental cleaning mechanism from alkaline dissolution to acid etching and chelation, enabling effective particle removal while reducing ammonia-induced substrate damage and improving manufacturing precision
4Reliability
If conventional cleaning liquids are used, then particle removal is improved, but metal and organic component adsorption increases
Solution Approach 1:
The invention changes the pH and chemical composition parameters by using a mixed acid system with controlled sulfuric acid and nitric acid concentrations. This parameter change creates a cleaning environment that minimizes metal ion dissolution and organic substance adsorption while maintaining effective particle removal, thereby reducing harmful adsorption effects
Solution Approach 2:
The invention converts the potential harm of acid-based cleaning (which could increase metal dissolution) into a benefit by optimizing the acid ratio and adding complexing agents. The controlled acid environment removes particles effectively while the added chemicals prevent excessive metal adsorption, transforming a potential harm into a beneficial controlled process
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 removability of silica, alumina, and silicon nitride particles, suppresses metal adsorption, and minimizes substrate etching, while maintaining a low environmental burden by using a synergistic approach with ozone water or hydrogen peroxide to decompose organic contaminants.
Implementation Method 1
ozone water or hydrogen peroxide, which effectively removes particles and metals without etching the substrate, and further reduces organic component adsorption
Data Source
AI summary
A semiconductor substrate cleaning liquid composition is provided that includes one or more types selected from the group consisting of a compound having at least two sulfonic acid groups per molecule, phytic acid, and a condensed phosphoric acid compound; an inorganic acid; and water. There is also provided a process for cleaning a semiconductor substrate that includes a first step of cleaning the semiconductor substrate using the semiconductor substrate cleaning liquid composition and, subsequent to the first step, a second step of cleaning the semiconductor substrate with pure water, ozone water formed by dissolving ozone gas in pure water, or aqueous hydrogen peroxide.