Dry Etching Pt-Mn Films Using Halogen-Free Plasma
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Solution Overview
Problem
Existing dry etching methods for Pt—Mn layers, such as ion milling and halogen gas-based chemical etching, face challenges in achieving selectivity between mask and Pt—Mn layers, leading to tapered sidewalls and apparatus corrosion.
Innovation Solution
A dry etching method using a plasma of a gaseous mixture comprising H2, CO2, methane, and a rare gas, which suppresses sputtering and corrosion, allowing for vertical sidewall etching without halogen gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ion milling is used to etch the Pt—Mn layer, then etching capability is improved, but selectivity between mask layer and Pt—Mn layer deteriorates and sidewalls become tapered
Solution Approach 1:
The patent changes the etching mechanism from physical sputtering to chemical etching by selecting appropriate gas composition and pressure parameters. This allows effective etching of Pt—Mn while maintaining mask selectivity and achieving vertical sidewalls through chemical reaction control rather than physical ion bombardment
Solution Approach 2:
The patent replaces the mechanical ion milling process with a chemical etching process using plasma. This substitution eliminates the need for high-energy ion bombardment that causes mask damage and tapered sidewalls, while achieving effective Pt—Mn etching through chemical reactions
2Productivity
If halogen gas is used for chemical etching, then etching capability is improved, but apparatus corrosion accelerates and sidewalls become tapered
Solution Approach 1:
The patent extracts and eliminates halogen gases from the etching process while maintaining effective etching capability through alternative chemical species. This removal prevents apparatus corrosion and enables vertical sidewall formation without sacrificing etching effectiveness
Solution Approach 2:
The patent uses alternative gases that are less harmful to apparatus components compared to halogen gases. These alternative gases provide sufficient etching capability without the severe corrosion issues associated with halogen-based processes
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 method effectively etches Pt—Mn layers with vertical sidewalls, preventing apparatus corrosion and maintaining pattern shape integrity, while ensuring safety and operational efficiency.
Implementation Method 1
performing dry etching on the metal film by generating a plasma of an etching gas including a gaseous mixture of H2 gas, CO2 gas, methane gas and a rare gas
Implementation Method 2
generating a plasma of an etching gas including a gaseous mixture of H2 gas, CO2 gas, methane gas and a rare gas
Data Source
AI summary
A method for performing dry etching on a metal film containing Pt via a mask layer includes performing dry etching on the metal film by generating a plasma of an etching gas including a gaseous mixture of H2 gas, CO2 gas, methane gas and rare gas. With the dry etching method, it is possible to make a vertical sidewall of a hole or trench more vertical without using a halogen gas.