Molybdenum Film Etchant Composition for Selective Oxide Protection
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Solution Overview
Problem
Current etchant compositions fail to simultaneously remove molybdenum films and their modified oxides while effectively suppressing the etching of aluminum oxide and silicon oxide films, leading to unsatisfactory etching results in semiconductor manufacturing processes.
Innovation Solution
An etchant composition comprising an inorganic acid, an oxidizing agent, a fluorine compound, a pH adjuster, and a specific additive, which maintains a fast etching rate for molybdenum films while minimizing the etching of aluminum oxide and silicon oxide films, allowing for the simultaneous removal of molybdenum and molybdenum oxide films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional etchant composition is used to etch molybdenum film, then the molybdenum film can be removed, but the aluminum oxide film and silicon oxide film are also etched, leading to damage of these insulating films
Solution Approach 1:
The patent modifies the chemical composition parameters of the etchant by incorporating specific inhibitors (phosphoric acid, benzenesulfonic acid, or toluenesulfonic acid) along with hydrofluoric acid and hydrogen peroxide. This parameter change allows selective etching of molybdenum and molybdenum oxide while suppressing attack on aluminum oxide and silicon oxide films, resolving the contradiction between etching efficiency and film protection.
Solution Approach 2:
The patent introduces intermediary substances (phosphoric acid, benzenesulfonic acid, or toluenesulfonic acid) that act as selective inhibitors. These intermediaries preferentially adsorb onto the surfaces of aluminum oxide and silicon oxide films, forming protective complexes that prevent the etchant from attacking these insulating films while allowing molybdenum and molybdenum oxide to be etched.
2Productivity
If a conventional etchant composition is used to etch molybdenum film, then the molybdenum film can be removed, but modified molybdenum film such as molybdenum oxide film is not simultaneously removed, leading to particle generation
Solution Approach 1:
The patent adjusts the oxidizing power and pH parameters of the etchant by combining hydrogen peroxide with hydrofluoric acid and specific inhibitors. This parameter modification enables the etchant to effectively remove both metallic molybdenum and oxidized molybdenum oxide films simultaneously, preventing particle generation while maintaining high etching productivity.
Solution Approach 2:
The patent creates a composite etchant system combining multiple chemical components (hydrofluoric acid, hydrogen peroxide, and inhibitors such as phosphoric acid, benzenesulfonic acid, or toluenesulfonic acid) in specific concentrations. This composite formulation synergistically achieves both molybdenum and molybdenum oxide removal capabilities, resolving the contradiction between etching speed and complete film removal reliability.
3Productivity
If the etching process is optimized to remove molybdenum film quickly, then productivity is improved, but the selectivity against aluminum oxide and silicon oxide films deteriorates
Solution Approach 1:
The patent optimizes the concentration parameters of the etchant components, specifically using hydrofluoric acid at 0.01-10 wt%, hydrogen peroxide at 0.1-5 wt%, and inhibitors at 0.1-5 wt%. This parameter optimization achieves high etching rates for molybdenum while maintaining selectivity against aluminum oxide and silicon oxide films through the inhibitory action of the added compounds.
Solution Approach 2:
The patent employs intermediary inhibitor substances that selectively interact with aluminum oxide and silicon oxide surfaces, forming protective layers that reduce etching rates for these materials. This intermediary action maintains high selectivity even at elevated etching speeds, allowing fast molybdenum removal without compromising the integrity of insulating films.
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 etchant composition achieves satisfactory etching of molybdenum films while significantly suppressing the etching of aluminum oxide and silicon oxide films, addressing the limitations of conventional etchant compositions and preventing particle generation, and is applicable to various wet etching processes in semiconductor manufacturing.
Implementation Method 1
The etchant composition significantly suppresses the etching of an aluminum oxide film (AlOx) and silicon oxide film (SiOx) while simultaneously removing a molybdenum film (Mo) and modified film (molybdenum oxide film (MoOx))
Implementation Method 2
there is a need for an etchant composition that can remove the molybdenum film (Mo) and a modified molybdenum film such as a molybdenum oxide film (MoOx) generated during the etching process at the same time
Data Source
AI summary
The present invention relates to an etchant composition for etching a molybdenum film and a modified molybdenum film while suppressing the etching of an aluminum oxide film and a silicon oxide film, and an etching method therefor, wherein the etchant composition comprises, with respect to the total weight of the composition: 0.1 to 10% by weight of inorganic acid; 0.001 to 5% by weight of an oxidizer; 0.001 to 3% by weight of a fluorine compound; 2 to 4% by weight of a pH adjusting agent; 0.0001 to 2% by weight of an additive; and a residual amount of water.