Semiconductor Cleaning Composition for Residue Removal Without Metal Corrosion
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Solution Overview
Problem
Conventional cleaning solutions for semiconductor substrates are ineffective in removing plasma etch and ash residues, particularly for metals like aluminum and copper, and can be corrosive, posing challenges as device geometries shrink and environmental concerns increase.
Innovation Solution
A non-corrosive cleaning composition comprising hydroxylamine, polyaminopolycarboxylic acid as a chelating agent, substituted or unsubstituted benzotriazole as a corrosion inhibitor, water-soluble organic solvents, and quaternary ammonium hydroxide, with a pH between 6 and 11, effectively dissolves and removes a broad range of residues without damaging substrate materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional cleaning solutions are used to remove plasma etch residues, then cleaning effectiveness is improved, but substrate corrosion increases
Solution Approach 1:
The patent changes the chemical parameters of the cleaning solution by using a buffered formulation with controlled pH (maintained between 7-10.5) and specific concentration ratios of buffering agents. This parameter control allows the solution to effectively remove residues while preventing substrate corrosion through balanced chemical reactivity.
Solution Approach 2:
The cleaning solution employs a composite chemical formulation containing multiple components including hydroxylamine derivatives, buffering agents (phosphates, borates, silicates), chelating agents, and surfactants. This composite approach combines the benefits of each component to achieve both effective residue removal and corrosion protection simultaneously.
2Reliability
If stronger cleaning chemistries are used to remove difficult residues, then residue removal capability is improved, but selectivity and substrate damage control worsen
Solution Approach 1:
The cleaning solution exhibits local quality by having different components target specific types of residues selectively. Hydroxylamine derivatives specifically address organic and metal oxide residues, while chelating agents target metal contaminants, and surfactants address organic films. This localized chemical action allows effective removal of various residues without uniform aggressive attack on the substrate.
Solution Approach 2:
The buffered formulation acts as an intermediary system that mediates between the cleaning agents and the substrate. The buffering agents (phosphates, borates, silicates) control the chemical environment to enable residue removal while preventing excessive reactivity that would damage the substrate, thus serving as a protective intermediary.
3Productivity
If conventional stripping methods are used to remove photoresist, then bulk resist removal is achieved, but incomplete removal of crosslinked resist and inorganic residues occurs
Solution Approach 1:
The cleaning process is segmented into multiple functional components within the solution: hydroxylamine derivatives for crosslinked resist and metal oxide residues, chelating agents for inorganic metal residues, and surfactants for organic photoresist films. This segmentation of cleaning functions within a single formulation enables comprehensive removal of all residue types that conventional single-function strippers cannot address.
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 composition reliably removes insoluble residues such as photoresist, organometallic compounds, and metal oxides from semiconductor substrates while being non-corrosive to exposed metals, ensuring high cleaning efficiency and environmental safety.
Implementation Method 1
The composition reliably removes insoluble residues such as photoresist, organometallic compounds, and metal oxides from semiconductor substrates
Implementation Method 2
substituted or unsubstituted benzotriazole as a corrosion inhibitor
Implementation Method 3
polyaminopolycarboxylic acid as a chelating agent
Data Source
AI summary
This disclosure relates to a cleaning composition that contains 1) at least one redox agent; 2) at least one first chelating agent, the first chelating agent being a polyaminopolycarboxylic acid; 3) at least one second chelating agent different from the first chelating agent, the second chelating agent containing at least two nitrogen-containing groups; 4) at least one metal corrosion inhibitor, the metal corrosion inhibitor being a substituted or unsubstituted benzotriazole; 5) at least one organic solvent selected from the group consisting of water soluble alcohols, water soluble ketones, water soluble esters, and water soluble ethers; 6) water; and 7) optionally, at least one pH adjusting agent, the pH adjusting agent being a base free of a metal ion. This disclosure also relates to a method of using the above composition for cleaning a semiconductor substrate.