Cerium-Phosphoric Etching for Selective Silicon Carbonitride Removal
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Solution Overview
Problem
There is a lack of an effective etching solution that can selectively etch silicon carbonitride compared to silicon oxide, limiting its use in semiconductor manufacturing.
Innovation Solution
A homogeneous etching solution containing phosphoric acid, water, and cerium ions is developed, which significantly improves the etching rate of silicon carbonitride while maintaining a similar etching rate for silicon nitride and minimizing the etching of silicon oxide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a phosphoric acid aqueous solution is used for etching, then silicon nitride can be etched selectively, but silicon carbonitride is hardly etched
Solution Approach 1:
The patent changes the chemical composition parameters of the etching solution by adding cerium ions (0.001-0.2 mol/L) to the phosphoric acid aqueous solution. This parameter change enables the solution to etch silicon carbonitride effectively while maintaining selectivity against silicon oxide, resolving the contradiction between etching capability and selectivity.
Solution Approach 2:
The patent creates a composite etching solution by combining phosphoric acid, water, and cerium ions. This composite composition synergistically achieves high etching rates for both silicon nitride and silicon carbonitride while maintaining selective etching against silicon oxide, solving the limitation of using phosphoric acid alone.
2Productivity
If a composition containing oxidizing agent, fluorine compound, and water is used for etching silicon carbonitride, then etching can be achieved, but the etching rate is less than 250 Å/30 min and silicon oxide film is also etched
Solution Approach 1:
The patent changes the chemical composition by using cerium ions instead of traditional oxidizing agents and fluorine compounds. This parameter change achieves high etching rates for silicon carbonitride (exceeding 250 Å/30 min) while maintaining excellent selectivity against silicon oxide, simultaneously improving both productivity and manufacturing precision.
Solution Approach 2:
The patent uses a simple, inexpensive phosphoric acid-based etching solution with cerium ions instead of complex compositions containing oxidizing agents and fluorine compounds. This simpler solution achieves superior performance in both etching rate and selectivity, eliminating the need for expensive and harmful chemicals.
3Reliability
If silicon carbonitride film is used in semiconductor manufacturing, then better performance is achieved, but lack of effective etching solution limits its use
Solution Approach 1:
The patent changes the etching solution composition to include cerium ions in phosphoric acid, which enables effective etching of silicon carbonitride. This parameter change makes silicon carbonitride films easy to manufacture and process, removing the limitation that previously hindered their widespread use in semiconductor devices.
Solution Approach 2:
The patent creates a universal etching solution that can etch multiple materials (silicon nitride, silicon carbonitride, and silicon oxide) with appropriate selectivity. This multi-functional solution enables the widespread adoption of silicon carbonitride films in semiconductor manufacturing by providing a practical etching method.
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 solution achieves high selectivity in etching silicon carbonitride over silicon oxide, allowing for efficient processing in semiconductor device manufacturing, and can be used for both silicon carbonitride and silicon nitride etching, reducing the need for multiple etching solutions.
Implementation Method 1
further addition of cerium ions to a phosphoric acid aqueous solution, which has been used for selective etching of silicon nitride in the prior art, can greatly improve the etching rate of silicon carbonitride
Implementation Method 2
An etching solution for etching silicon carbonitride, the etching solution composed of a homogeneous solution containing phosphoric acid, water, and a cerium ion
Data Source
AI summary
Silicon carbonitride with excellent dielectric and/or other properties may be used in manufacturing semiconductor devices. The manufacturing often requires etching silicon carbonitride without etching silicon oxide, but there is no known etching solution that sufficiently selectively etches silicon carbonitride containing carbon compared with silicon nitride used for the same purpose. An object of the present invention is to provide: an etching solution with a high etching selectivity ratio of silicon carbonitride to silicon oxide; a method of treating a substrate, the method including a step of bringing the etching solution into contact with the substrate; and a method of manufacturing a semiconductor device, the method including the method of treating a substrate. The object is achieved by an etching solution for etching silicon carbonitride, the etching solution composed of a homogeneous solution containing phosphoric acid, water, and a cerium ion.