Semiconductor Cleaning Liquid for Low-k Films
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Solution Overview
Problem
Conventional cleaning liquids for semiconductor device substrates are ineffective in removing contaminants from hydrophobic low-dielectric constant insulating films and Cu wiring without corroding the substrate, and they require prolonged rinsing periods due to insufficient substrate-cleaning effects and poor water rinsability.
Innovation Solution
A cleaning liquid comprising a combination of polycarboxylic acid, sulfonic acid type anionic surfactant, and carboxylic acid type anionic surfactant, which improves wettability and reduces zeta potential to prevent colloidal silica adhesion, ensuring effective removal of contaminants without corroding the substrate and facilitating short rinsing periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a cleaning liquid with high dissolving or decomposing ability is used to remove organic residues, then the organic residues can be effectively removed, but the metallic wiring is corroded
Solution Approach 1:
The patent changes the chemical parameters of the cleaning liquid by using a specifically formulated surfactant system (anionic surfactant at 0.01-10% by weight and nonionic surfactant at 0.01-10% by weight) instead of traditional strong solvents. This parameter change allows effective cleaning while reducing corrosiveness to Cu wiring, resolving the contradiction between cleaning effectiveness and corrosion prevention
Solution Approach 2:
The patent employs a composite surfactant system combining anionic and nonionic surfactants in specific proportions. This composite approach creates synergistic effects that enhance cleaning performance on hydrophobic low-k surfaces while maintaining mildness toward metallic wiring, simultaneously achieving both cleaning effectiveness and corrosion protection
2Manufacturing precision
If the low-dielectric constant film is cleaned effectively, then contaminants are removed, but the cleaning liquid requires prolonged rinsing periods due to poor water rinsability
Solution Approach 1:
The patent replaces traditional mechanical rinsing processes with a chemically optimized surfactant system that provides inherent rinsability. The specific surfactant composition (0.01-10% anionic + 0.01-10% nonionic by weight) reduces surface tension and improves wetting, allowing rapid removal of cleaning residues with shorter rinsing times while maintaining effective contaminant removal
Solution Approach 2:
The patent changes the physical-chemical parameters of the cleaning liquid by optimizing surfactant concentrations and types. This creates a formulation that balances cleaning power with rapid rinsability, reducing the rinsing period from prolonged durations to manageable times while maintaining effective contaminant removal from low-k surfaces
3Reliability
If colloidal silica zeta potential is controlled to be negative to prevent adhesion, then fine particles are prevented from adhering, but the cleaning liquid becomes less effective at removing organic residues
Solution Approach 1:
The patent creates a universal surfactant system that performs multiple functions simultaneously: the anionic surfactant (0.01-10% by weight) controls zeta potential to prevent particle adhesion, while the nonionic surfactant (0.01-10% by weight) effectively removes organic residues. This multi-functional formulation resolves the contradiction by making a single cleaning liquid effective for both particle prevention and organic residue removal
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 liquid simultaneously removes fine particles, organic contaminants, and metallic contaminants from semiconductor substrates without corrosion, achieving high cleaning efficiency and satisfactory water rinsability, thereby reducing the cleaning time and improving substrate quality.
Implementation Method 1
a sulfonic acid type anionic surfactant (B) and a carboxylic acid type anionic surfactant (C)
Implementation Method 2
improves wettability and reduces zeta potential to prevent colloidal silica adhesion
Implementation Method 3
control the zeta potential of the colloidal silica so as to be negative
Implementation Method 4
the fine colloidal silica particles which have been positively charged are apt to adhere to the negatively charged surface
Implementation Method 5
at least either one of a polycarboxylic acid and a hydroxycarboxylic acid
Data Source
AI summary
The invention relates to a cleaning liquid for semiconductor device substrates comprising the following components (A) to (D) and a method of cleaning semiconductor device substrates:(A) at least either one of a polycarboxylic acid and a hydroxycarboxylic acid;(B) a sulfonic acid type anionic surfactant;(C) a carboxylic acid type anionic surfactant; and(D) water.