Plasma Radical Etching of Stacked Insulators for Nitride Selectivity
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Solution Overview
Problem
In semiconductor manufacturing, the high integration of devices leads to issues with etching selectivity and uniformity due to thin insulating films, causing unintended etching and restricted wet etching, especially when forming patterns with alternating silicon nitride and silicon oxide films.
Innovation Solution
A substrate processing apparatus and method that involves controlling the temperatures of the substrate support unit and gas distribution unit, using a halogen-containing gas with inert gases like NF3 and Ar, and generating radicals to selectively etch silicon nitride films laterally relative to silicon oxide films, ensuring uniform etching profiles through precise temperature and gas control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wet etching is used to etch thin insulating films, then the etching process can be performed, but etching selectivity deteriorates causing unintended insulating films to be etched
Solution Approach 1:
The patent changes the etching method from wet etching to dry etching using radicals generated by a plasma reactor. This parameter change enables selective etching of silicon nitride films while preserving silicon oxide films, achieving the required etching selectivity for highly integrated semiconductor devices with thin insulating films
2Productivity
If the insulating films are made thinner for high integration, then device integration increases, but etching selectivity deteriorates causing unintended etching
Solution Approach 1:
The patent employs dry etching with specifically controlled radicals (using NF3 and Ar gases) to achieve selective etching of thin silicon nitride films. This enables the processing of highly integrated devices with thinner insulating films while maintaining high etching selectivity, resolving the contradiction between device integration and etching precision
3Power
If temperature of gas distribution unit is increased, then radical generation improves, but temperature control precision deteriorates affecting etching uniformity
Solution Approach 1:
The patent optimizes the temperature of the gas distribution unit within a specific range (room temperature to 70°C) to balance radical generation efficiency with etching uniformity. This parameter control ensures that radicals are effectively generated while maintaining uniform etching across the substrate surface, achieving both high power efficiency 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
Achieves high etch selectivity and uniformity in etching silicon nitride films relative to silicon oxide films, addressing the challenges of non-uniform etching in highly integrated semiconductor devices.
Implementation Method 1
generating radicals by applying power to the plasma reactor to activate the halogen-containing gas
Implementation Method 2
heating the substrate support unit and the gas distribution unit such that a temperature of the gas distribution unit is maintained equal to or lower than a temperature of the substrate support unit
Data Source
AI summary
A substrate processing method using a substrate processing apparatus which comprises a process chamber in which a reaction space is formed to process a substrate in which a composite layer pattern having a plurality of first insulating layers and a plurality of second insulating layers alternately stacked thereon is formed, a substrate support unit, a gas distribution unit, and a plasma reactor, the method comprising the steps of: heating the substrate support unit and the gas distribution unit such that a temperature of the gas distribution unit is maintained equal to or lower than a temperature of the substrate support unit; supplying a reactive gas including a halogen-containing gas to the plasma reactor; generating radicals by applying power to the plasma reactor to activate the halogen-containing gas; and at least partially etching the plurality of first insulating layers in a lateral direction selectively with respect to the plurality of second insulating layers by supplying the radicals onto the substrate mounted on the substrate support unit through the gas distribution unit.