Etchant Composition for Nitride Film Selective Etching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In the fabrication of integrated circuit devices, there is a need for an etchant composition that prevents the generation of unnecessary particles and abnormal growth of by-products on oxide films during nitride film etching, while ensuring sufficient nitride film-to-oxide film etch selectivity, especially for complex and fine structures.
Innovation Solution
An etchant composition comprising phosphoric acid, a siloxane compound, ammonium phosphate, and a solvent, such as trimethylamine, which selectively etches nitride films with high selectivity relative to oxide films, preventing damage to the oxide film and maintaining etch rate stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional etchant compositions are used for nitride film etching, then etching process is simple, but unnecessary particles and abnormal growth of by-products are generated on oxide film surfaces
Solution Approach 1:
The patent introduces a chelating agent as an intermediary substance that binds to metal ions (such as silicon ions) released during nitride film etching. This chelating agent prevents the metal ions from reacting with oxide films to form abnormal by-products or particles, thereby resolving the contradiction between achieving effective etching and preventing harmful surface defects on oxide films.
Solution Approach 2:
The patent modifies the chemical composition parameters of the etchant by adding specific components (chelating agents, buffer substances, and surfactants) to control the chemical reactions during etching. These parameter changes enable selective removal of nitride films while preventing unwanted side reactions that would otherwise generate particles or abnormal growth on oxide film surfaces.
2Manufacturing precision
If conventional etchant compositions are used, then formulation is simple, but sufficient nitride film-to-oxide film etch selectivity cannot be achieved
Solution Approach 1:
The patent creates a composite etchant formulation by combining multiple functional components: inorganic acid (for etching power), chelating agent (for ion binding), buffer substance (for pH control), and surfactant (for surface activity). This composite composition achieves high etch selectivity between nitride and oxide films while managing the complexity through systematic integration of complementary substances.
Solution Approach 2:
The patent achieves high etch selectivity by carefully controlling chemical parameters including pH level (maintained between 2-4 through buffer substances), concentration ratios of different components, and temperature conditions. These parameter optimizations enable selective nitride film removal while minimizing oxide film damage, despite the increased composition complexity.
3Productivity
If etching process is performed without proper composition control, then process is fast, but electrical properties of oxide films deteriorate
Solution Approach 1:
The chelating agent acts as a mediator that captures metal ions released during rapid etching, preventing these ions from depositing on or reacting with oxide films. This intermediary function allows high-speed etching to proceed without compromising the electrical integrity of oxide films, thus resolving the contradiction between productivity and reliability.
Solution Approach 2:
The patent maintains optimal pH levels (2-4) through buffer substances during the etching process, which enables fast etching rates while preventing conditions that would degrade oxide film electrical properties. This parameter control ensures that high productivity does not come at the cost of device reliability.
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 high nitride film-to-oxide film etch selectivity of 200:1 to 600:1, ensuring stable and reliable nitride film etching processes, improving productivity and reducing electrical property deterioration of oxide films.
Implementation Method 1
selectively etching nitride films having variously shaped patterns may be required to form electronic devices having complicated and fine structure
Implementation Method 2
does not cause generation of unnecessary particles or undesired abnormal growth of by-products on a surface of an oxide film
Data Source
AI summary
An etchant composition includes an inorganic acid, a siloxane compound, an ammonium compound, and a solvent, wherein the siloxane compound is represented by General Formula (I):A method of fabricating an integrated circuit device includes forming a structure on a substrate, the structure having a surface on which an oxide film and a nitride film are exposed; and selectively removing the nitride film from the oxide film and the nitride film by bringing the etchant composition into contact with the structure.