Ru Removal Composition for Better Wetting on Semiconductor Bevels
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Solution Overview
Problem
Existing compositions for removing ruthenium (Ru) from semiconductor substrates exhibit insufficient removability, particularly in non-flat surfaces such as the bevel portions, due to poor compatibility between the etchant and Ru, leading to reduced contact area and inadequate removal performance.
Innovation Solution
A composition comprising periodic acid or its salt, a quaternary ammonium salt, an anionic surfactant with a sulfonic acid or phosphoric acid group, and a nonionic surfactant with a polyoxyalkylene chain, which enhances the contact area and improves Ru removability by reducing the contact angle with Ru.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etchants are used to remove ruthenium, then the etching process can be performed, but the removability of ruthenium is insufficient particularly on non-flat surfaces such as bevel portions
Solution Approach 1:
The patent changes the chemical parameters of the etching composition by incorporating specific surfactants (ionic and nonionic) alongside periodic acid or its salts. This parameter change modifies the surface properties of the etchant to reduce contact angle with ruthenium surfaces, thereby improving wetting and contact area on non-flat surfaces like bevel portions, which directly enhances Ru removability
Solution Approach 2:
The patent introduces surfactants as intermediary substances that mediate between the etchant and the ruthenium surface. These surfactants act as intermediaries that improve the interaction between the etching solution and the Ru surface, enabling better penetration and contact on difficult-to-reach areas such as bevel portions,从而提升去除效果
2Ease of operation
If the etchant compatibility with Ru is poor, then the etching process can proceed, but the contact area between etchant and Ru is reduced
Solution Approach 1:
The patent modifies the physical-chemical parameters of the etching solution by adding surfactants that change the surface tension and wetting properties. This parameter change improves the contact angle between the etchant and Ru surface, allowing the etching process to proceed effectively while maximizing contact area even on complex surface geometries
3Device complexity
If conventional compositions are used, then the process can be simple, but the Ru removability is insufficient
Solution Approach 1:
The patent creates a composite etching composition by combining periodic acid or its salts with specific ionic surfactants and nonionic surfactants. This composite formulation integrates the oxidizing power of periodic acid with the surface-active properties of surfactants, achieving superior Ru removability while maintaining a relatively simple liquid composition format that does not require complex equipment or multi-step processes
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 achieves superior Ru removability on semiconductor substrates, including bevel portions, by increasing the contact area and improving removal performance through the use of specific surfactants and periodic acid or its salt.
Implementation Method 1
a periodic acid or a salt thereof
Implementation Method 2
at least one ionic surfactant selected from the group consisting of a quaternary ammonium salt, an anionic surfactant, a cationic surfactant, and an amphoteric surfactant; and a nonionic surfactant
Implementation Method 3
improves Ru removability by reducing the contact angle with Ru
Data Source
AI summary
The present invention provides a composition having excellent Ru removability, a method for treating an object to be treated using the composition, and a method for manufacturing a semiconductor device. The composition according to the embodiment of the present invention includes periodic acid or a salt thereof, a quaternary ammonium salt, at least one ionic surfactant selected from the group consisting of an anionic surfactant, a cationic surfactant, and an amphoteric surfactant, and a nonionic surfactant.