Selective Silicon Etching Composition for Metal Film Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing etchants for silicon etching in semiconductor manufacturing exhibit low selectivity to metal films, leading to increased defect rates and issues like short circuits due to non-selective etching of metals such as titanium nitride and tungsten.
Innovation Solution
A composition comprising a fluorine compound, nitric acid, acetic acid, phosphoric acid, and a cationic oligomer with a molecular weight of 100 to 100,000, which enhances the etch selectivity of silicon relative to metal films by controlling etch rates and minimizing metal corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an acidic etchant containing hydrofluoric acid and oxidizing species is used for silicon etching, then the etching capability is sufficient, but the selectivity to metal films deteriorates leading to non-selective etching of titanium nitride and tungsten
Solution Approach 1:
The patent changes the chemical parameters of the etching composition by replacing traditional acidic etchants with a new composition containing hydrofluoric acid at controlled concentrations (0.1-10%), oxidizing agents, and specific additives. This parameter optimization achieves high silicon etching rates while maintaining selectivity against metal films, resolving the contradiction between etching capability and selectivity
Solution Approach 2:
The patent introduces intermediary substances such as oxidizing agents (potassium permanganate, ammonium persulfate) and specific additives that mediate the etching process. These intermediaries enable selective removal of silicon while protecting metal films through controlled chemical reactions, thereby improving selectivity without sacrificing etching efficiency
2Productivity
If traditional acidic etchants are used for bulk silicon etching, then the etching process is efficient, but metal films are etched non-selectively causing defects in subsequent processes
Solution Approach 1:
The patent optimizes the concentration parameters of hydrofluoric acid (0.1-10%) and oxidizing agents to achieve high etching efficiency while maintaining pattern accuracy. The balanced composition enables rapid silicon removal without compromising the integrity of metal patterns, resolving the contradiction between productivity and manufacturing precision
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 an etch rate of silicon of 3 μm/min or more with selectivity to metal films of 100 or more, significantly reducing defects and improving process reliability.
Implementation Method 1
a fluorine compound; nitric acid; acetic acid; phosphoric acid
Implementation Method 2
a cationic oligomer having a molecular weight of Mw 100 to 100,000
Implementation Method 3
oxidizing species such as nitric acid and sulfuric acid
Data Source
AI summary
The present invention relates to a composition for selectively etching silicon on a surface on which a metal film and silicon (Si) are exposed. According to the present invention, it is possible to improve etch selectivity of silicon on the semiconductor surface on which the metal film and silicon are exposed.