Silicon Nitride Etching with Halogen Fluoride Without Plasma
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Solution Overview
Problem
Current etching methods for silicon nitride either use costly plasma or fail to selectively etch silicon nitride, lacking effective plasmaless etching solutions.
Innovation Solution
An etching method using an etching gas containing halogen fluoride compounds like bromine or iodine fluorides under controlled pressure and temperature, without plasma, to selectively etch silicon nitride with high selectivity ratios, utilizing etching-resistant materials like silicon dioxide or photoresist.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plasma etching method is used to etch silicon nitride, then etching capability is achieved, but manufacturing cost increases
Solution Approach 1:
The patent extracts the essential etching function from plasma and implements it through pure chemical reactions using halogen fluoride gases. The plasma component is removed while maintaining the etching capability through chemical affinity between halogen fluorides and silicon nitride, thereby reducing manufacturing cost while preserving etching reliability.
Solution Approach 2:
The patent replaces the plasma-based physical-chemical etching system with a pure chemical etching system using halogen fluoride gases. This substitution eliminates the need for plasma generation equipment and associated costs, while achieving effective silicon nitride etching through chemical reactions alone.
2Ease of manufacture
If conventional plasmaless etching methods are used, then manufacturing cost is reduced, but selective etching of silicon nitride cannot be achieved
Solution Approach 1:
The patent changes the chemical parameters of the etching gas from conventional options to halogen fluoride gases, which have specific chemical affinity for silicon nitride. This parameter change enables selective etching of silicon nitride while maintaining plasmaless conditions, thus achieving both cost reduction and manufacturing precision.
Solution Approach 2:
The patent uses composite etching gas compositions containing halogen fluorides combined with inert gases or other additives to optimize both the selective etching of silicon nitride and the protection of other materials. This composite approach achieves high selectivity ratios while maintaining cost-effective plasmaless processing.
3Ease of manufacture
If halogen fluoride etching gas is used without plasma, then manufacturing cost is reduced and apparatus corrosion is prevented, but etching selectivity must be optimized
Solution Approach 1:
The patent optimizes etching selectivity by adjusting parameters such as gas composition ratios, pressure, and temperature when using halogen fluoride etching gases. These parameter changes enable high selectivity ratios (10 or more) while maintaining the cost and durability advantages of plasmaless processing.
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
Enables selective etching of silicon nitride without plasma, reducing costs and preventing apparatus corrosion, while allowing for precise microfabrication and integration in semiconductor manufacturing, such as in 3D-NAND flash memories.
Implementation Method 1
placing an etching object containing silicon nitride in an etching gas containing halogen fluoride, the halogen fluoride being a compound of bromine or iodine and fluorine, to etch the silicon nitride
Data Source
AI summary
There is provided an etching method for silicon nitride that enables selective etching of silicon nitride without using plasma. The etching method for silicon nitride includes placing etching object (12) containing silicon nitride in an etching gas containing halogen fluoride, which is a compound of bromine or iodine and fluorine, to etch the silicon nitride of the etching object (12) without using plasma under a pressure of 1 Pa to 80 kPa.