Selective Oxide Etch Composition for Silicon Nitride Protection
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Solution Overview
Problem
Conventional buffer etch solutions provide a high and stable etch rate for oxide layer removal but may damage silicon nitride layers.
Innovation Solution
A composition comprising 10% to 25% ammonium fluoride, 0.1% to 1% hydrogen fluoride, and 0.1% to 1% nitride inhibitor, which selectively etches metal oxides while minimizing damage to silicon nitride layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional buffer etch solutions are used to remove oxide layers, then a high and stable etch rate is achieved, but silicon nitride layers may be damaged
Solution Approach 1:
The patent modifies the chemical composition parameters of the etch solution by incorporating specific concentrations of ammonium fluoride (10-25% by weight), hydrogen fluoride (0.1-1% by weight), and nitride inhibitor (0.1-1% by weight). These parameter changes enable the solution to achieve high oxide etch rates while simultaneously protecting silicon nitride layers from damage, thus resolving the contradiction between productivity and harmful effects.
Solution Approach 2:
The patent introduces a nitride inhibitor as an intermediary substance in the etch solution. This intermediary component specifically interacts with silicon nitride layers to prevent their damage while allowing oxide layers to be etched at high rates. The nitride inhibitor acts as a protective mediator that enables the etching process to proceed efficiently without compromising the integrity of underlying silicon nitride structures.
2Productivity
If conventional buffer etch solutions are used, then oxide layer removal is efficient, but selectivity against silicon nitride layers is poor
Solution Approach 1:
The patent optimizes the chemical parameters of the etch solution by establishing specific concentration ranges for ammonium fluoride (10-25% by weight), hydrogen fluoride (0.1-1% by weight), and nitride inhibitor (0.1-1% by weight). These precise parameter adjustments create a solution that maintains high oxide etch rates while achieving superior selectivity, preventing etching of silicon nitride layers and thus resolving the contradiction between productivity and manufacturing precision.
Solution Approach 2:
The patent creates a composite etch solution system combining multiple chemical components: ammonium fluoride, hydrogen fluoride, and nitride inhibitor. This composite formulation leverages the synergistic effects of different chemicals to achieve both high oxide removal efficiency and excellent selectivity. The combination of these substances provides a balanced etching action that targets oxide layers while sparing silicon nitride layers, thereby resolving the selectivity-productivity contradiction.
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
Achieves high selectivity and etch rate for metal oxides without significantly affecting silicon nitride layers, maintaining structural integrity.
Implementation Method 1
the composition selectively etches the metal oxide surface
Implementation Method 2
the composition comprises 10% to 25% by weight of an ammonium fluoride and 0.1% to 1% by weight of a hydrogen fluoride
Data Source
AI summary
Composition, related systems and methods of removing metal oxides from a structure. The composition comprises 10% to 25% by weight of an ammonium fluoride based on a total weight of the composition. The composition comprises 0.1% to 1% by weight of a hydrogen fluoride based on a total weight of the composition. The composition comprises 0.1% to 1% by weight of a nitride inhibitor based on a total weight of the composition. When the composition contacts a structure comprising a silicon nitride surface and a metal oxide surface, the composition selectively etches the metal oxide surface.