Aqueous Alkaline Cleaning Compositions for Semiconductor Wafer Processing
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Solution Overview
Problem
Existing aqueous alkaline cleaning compositions for semiconductor wafer processing are prone to degradation upon oxygen exposure, leading to discoloration, loss of cleaning power, and erroneous sensor outputs, and fail to efficiently remove residues and contaminants from copper metallization surfaces without causing roughening.
Innovation Solution
Development of aqueous alkaline cleaning compositions with a pH range of 8 to 14, comprising thioamino acids with secondary or tertiary amino groups and mercapto groups, combined with quaternary ammonium hydroxides and functional additives like complexing agents, corrosion inhibitors, and surfactants, which effectively remove contaminants without decomposing or roughening copper surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional aqueous alkaline cleaning compositions are used, then cleaning power is provided, but the compositions degrade upon oxygen exposure causing discoloration and loss of cleaning efficacy
Solution Approach 1:
The patent changes the chemical parameters of the cleaning composition by using specific thioamino acids (cysteine, N-acetylcysteine, homocysteine) with controlled concentrations (0.1-20% wt) combined with quaternary ammonium hydroxides. This parameter optimization enables the composition to maintain stability and cleaning efficacy under oxygen exposure, resolving the contradiction between reliability and compositional stability.
2Productivity
If strong cleaning agents are used to remove residues and contaminants, then cleaning power is improved, but copper surfaces become roughened
Solution Approach 1:
The patent optimizes the pH parameter to ranges of 8-14 (preferably 9-13, most preferably 10-12) and controls the concentration of thioamino acids and quaternary ammonium hydroxides. These parameter changes enable effective removal of residues and contaminants while preventing copper surface roughening, thus resolving the contradiction between productivity and manufacturing precision.
Solution Approach 2:
The patent creates a composite cleaning system combining thioamino acids (cysteine, N-acetylcysteine, homocysteine) with quaternary ammonium hydroxides (tetramethylammonium hydroxide, tetraethylammonium hydroxide, choline). This composite material approach provides synergistic effects that enable effective contaminant removal while maintaining copper surface integrity, resolving the contradiction between cleaning power and surface quality.
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 new compositions maintain stability and cleaning efficacy even after prolonged oxygen exposure, efficiently removing residues and contaminants from semiconductor wafers and processing tools, preventing copper surface roughening and ensuring reliable tool function.
Implementation Method 1
comprising (A) at least one thioamino acid having at least one secondary or tertiary amino group and at least one mercapto group; and (B) at least one quaternary ammonium hydroxide
Implementation Method 2
comprising (A) at least one thioamino acid having at least one secondary or tertiary amino group and at least one mercapto group; and (B) at least one quaternary ammonium hydroxide
Implementation Method 3
comprising (C) at least one functional additive (C) selected from the group consisting of complexing or chelating agents, corrosion inhibiting agents, film-forming agents, bases, organic solvents, alcohols having at least one mercapto group, surfactants, pH-adjusting agents and metal free silicates
Implementation Method 4
aqueous alkaline cleaning compositions with a pH in the range of from 8 to 14
Data Source
AI summary
The aqueous alkaline cleaning composition comprising (A) at least one thioamino acid having at least one secondary or tertiary amino group and at least one mercapto group and (B) at least one quaternary ammonium hydroxide; the use of the alkaline cleaning composition for the processing of substrates useful for fabricating electrical and optical devices; and a method for processing substrates useful for fabricating electrical and optical devices making use of the said aqueous alkaline cleaning composition.