Selective Passivation Layer Removal Using Composite Acid Chemistry
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Solution Overview
Problem
Current chemical compositions used for removing amorphous passivation layers after plasma etching are ineffective in selectively targeting aluminum and copper, often attacking these materials along with the passivation layer, leading to unwanted damage.
Innovation Solution
A cleaning chemical composition comprising acetic acid, methanesulphonic acid, hydrofluoric acid, and water, with specific weight percentages, is used to selectively remove the passivation layer while protecting aluminum and copper, ensuring minimal attack on these materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If current chemical compositions are used to remove amorphous passivation layers, then the passivation layer can be removed, but aluminum and copper materials are also attacked and damaged
Solution Approach 1:
The patent modifies the chemical composition parameters by incorporating specific concentrations of hydrofluoric acid (0.1-5% by weight), acetic acid (5-30% by weight), and hydrogen peroxide (1-10% by weight), along with controlled temperature ranges (20-80°C) and exposure times (30 seconds to 5 minutes). These parameter changes enable selective removal of amorphous passivation layers while protecting aluminum and copper materials from damage.
2Productivity
If strong acids are used to effectively remove the passivation layer, then removal efficiency increases, but selectivity against aluminum and copper decreases
Solution Approach 1:
The patent employs a composite chemical composition combining multiple acids (hydrofluoric acid, acetic acid, and hydrogen peroxide) in specific proportions. This composite approach leverages the complementary properties of each acid: hydrofluoric acid for effective oxide removal, acetic acid for moderate etching control, and hydrogen peroxide for oxidation assistance. The synergistic interaction of these components achieves high removal efficiency while maintaining selectivity and protecting aluminum and copper layers.
3Loss of time
If the chemical composition is made more aggressive to remove the passivation layer faster, then productivity increases, but harmful effects on aluminum and copper increase
Solution Approach 1:
The patent optimizes process parameters including temperature (20-80°C), exposure time (30 seconds to 5 minutes), and chemical concentrations to achieve rapid yet selective passivation layer removal. By controlling these parameters, the process reduces cleaning time while preventing excessive lateral etching and damage to aluminum and copper materials.
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 the passivation layer while maintaining the integrity of aluminum and copper layers, reducing lateral etching and enhancing the precision of microelectronic component manufacturing processes.
Implementation Method 1
a first acidifying agent comprising hydrofluoric acid in a solvent constituted of a weak acid, the hydrofluoric acid enabling the metals and semiconductor materials in oxidised form of the passivation layer to be dissolved
Implementation Method 2
a weak acid comprising acetic acid, the weak acid content being between 20% by weight and 95% by weight, preferably between 50% by weight and 80% by weight, relative to the weight of the chemical composition
Implementation Method 3
a non-oxidising strong acid comprising methanesulphonic acid, the non-oxidising strong acid content being between 5% by weight and 50% by weight, preferably between 15% by weight and 50%, relative to the weight of the chemical composition
Implementation Method 4
the plasma ions react with the layer to be etched and form a reactive layer on the surface to be etched on the flanks of the patterns
Implementation Method 5
the volatile etching products from the reaction of the plasma ions with the layer to be etched are deposited on the flanks of the pattern
Implementation Method 6
then react with the chemical environment in order to form the passivation layer, for example by oxidation
Data Source
AI summary
A cleaning chemical composition suitable, for removing a passivation layer from a substrate, wherein the passivation layer comprises residues resulting from etching of said Substrate.