Wet Etching Composition for Low-k Insulation Removal
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Solution Overview
Problem
Current methods for removing low-k insulation materials and passivation layers from semiconductor substrates often damage the substrate and are economically inefficient, particularly during dry etching processes, and existing wet etching solutions fail to effectively remove these materials without damaging the substrate.
Innovation Solution
A composition comprising 5-40% fluorine compounds, 0.01-20% first oxidizing agents, and 10-50% second oxidizing agents, including hydrogen fluoride and sulfuric acid, is applied to the substrate to decompose and remove low-k and passivation materials without damaging the substrate, utilizing a wet etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dry etching process is used to remove low-k insulation material and passivation layer, then the insulation material can be removed, but the substrate is damaged
Solution Approach 1:
The patent replaces the mechanical/physical dry etching process with a chemical wet etching process using a specifically formulated composition containing hydrogen fluoride, ammonium fluoride, and oxidizing agents. This chemical approach selectively dissolves the insulation material and passivation layer without the mechanical damage caused by plasma etching, thereby removing the harmful effect on the substrate while maintaining removal effectiveness
Solution Approach 2:
The patent changes the etching parameters by using a wet chemical process instead of dry plasma process. The composition parameters (concentrations of HF, NH4F, and oxidizing agents like H2O2 and HNO3) are optimized to achieve selective etching of the insulation material and passivation layer at controlled rates, preventing substrate damage while ensuring complete removal of the targeted layers
2Object-affected harmful factors
If conventional wet etching solutions are used, then the process is gentler on substrates, but they fail to effectively remove low-k materials and passivation layers
Solution Approach 1:
The patent creates a composite etching composition by combining hydrogen fluoride (for attacking silicon oxide in low-k materials), ammonium fluoride (for enhancing etching capability and protecting substrate), and oxidizing agents (H2O2 and HNO3 for removing organic components and passivation layers). This composite formulation achieves both high etching efficiency for difficult-to-remove materials and gentle treatment of the substrate, resolving the contradiction between effectiveness and substrate safety
Solution Approach 2:
The patent employs strong oxidizing agents (hydrogen peroxide and nitric acid) in the composition to accelerate the removal of organic-based low-k materials and passivation layers. These oxidants break down the organic components chemically, significantly improving etching efficiency and productivity compared to conventional weak etching solutions, while the overall formulation maintains substrate safety through controlled chemical reactions
3Ease of manufacture
If substrate recycling is implemented, then manufacturing costs are reduced, but existing methods cause substrate damage that prevents effective recycling
Solution Approach 1:
The patent replaces the damaging dry etching method with a gentle wet chemical etching process that removes insulation materials and passivation layers without compromising substrate integrity. This substitution enables the substrate to be reused for subsequent devices, making recycling economically viable by maintaining substrate reliability while reducing manufacturing costs through resource reuse
4Productivity
If etching rate is increased to improve productivity, then removal efficiency is improved, but substrate damage increases
Solution Approach 1:
The patent optimizes the chemical composition parameters to achieve selective etching with controlled rates. The concentrations of hydrogen fluoride, ammonium fluoride, and oxidizing agents are carefully balanced to ensure that the etching rate is sufficiently high for productivity while the chemical selectivity prevents substrate damage. The oxidizing agents enhance the etching rate for organic materials without increasing damage to the inorganic substrate
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 effectively removes low-k and passivation layers with controlled etching rates, preventing substrate damage and reducing manufacturing costs by enhancing process efficiency and allowing for substrate recycling.
Implementation Method 1
A composition including about 5 to about 40 percent by weight of a fluorine compound, about 0.01 to about 20 percent by weight of a first oxidizing agent, about 10 to about 50 percent by weight of a second oxidizing agent, and a remaining water
Implementation Method 2
about 0.01 to about 20 percent by weight of a first oxidizing agent, about 10 to about 50 percent by weight of a second oxidizing agent
Data Source
AI summary
In one aspect, a composition is provided which is capable of removing an insulation material which includes at least one of a low-k material and a passivation material. The composition of this aspect includes about 5 to about 40 percent by weight of a fluorine compound, about 0.01 to about 20 percent by weight of a first oxidizing agent, about 10 to about 50 percent by weight of a second oxidizing agent, and a remaining water.