Plasma Etching Magnetic and Phase Change Memory Materials
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Solution Overview
Problem
Current etching processes for magnetic and phase change memory devices face challenges such as low etch rates, corrosion, and electrical shorts due to conductive polymers, making it difficult to form high-quality pattern structures with narrow pitches and maintaining material composition ratios.
Innovation Solution
A plasma reactive etching process using a gas mixture of ammonia and fluorine-containing gases, such as SF6, is employed to form pattern structures with magnetic or phase change materials, ensuring minimal polymer attachment and maintaining material composition ratios, while controlling etching conditions like temperature and pressure to achieve acute sidewall angles and precise dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional etching processes are used on magnetic metal, then the etching can be performed, but the etch rate is very low and conductive polymer attaches to sidewalls causing electrical shorts
Solution Approach 1:
The patent changes the chemical parameters of the etching process by using a specific gas mixture containing ammonia (20-80 sccm) and fluorocarbon (10-30 sccm) at controlled pressure (10-100 mTorr) and power (100-500 W). This parameter optimization achieves both high etch rate for magnetic metal and minimal polymer deposition on sidewalls, preventing electrical shorts between MTJ structures.
Solution Approach 2:
The patent uses a composite etching gas system combining ammonia and fluorocarbon gases. Ammonia provides the etching action on magnetic metal while fluorocarbon controls polymer formation. The synergistic interaction between these two gases creates an etching environment that simultaneously achieves high removal rate and clean sidewalls without electrical shorts.
2Manufacturing precision
If conventional etching processes are used on phase change material, then etching can be performed, but forming narrow pitch patterns is difficult and material composition ratios change
Solution Approach 1:
The patent optimizes etching parameters including gas flow rates (ammonia 20-80 sccm, fluorocarbon 10-30 sccm), pressure (10-100 mTorr), and power (100-500 W) to achieve anisotropic etching. This produces vertical sidewalls with acute angles suitable for narrow pitch patterns while maintaining uniform etching across the phase change material layer, preserving the Ge-Sb-Te composition ratio.
Solution Approach 2:
The etching process creates different etching characteristics at different locations: high verticality at the sidewalls for narrow pitch patterns and uniform composition preservation in the bulk material. The plasma chemistry provides localized control where the etching front progresses uniformly through the phase change material while sidewalls remain protected from excessive lateral etching.
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
This method enhances the formation of magnetic and phase change memory devices by reducing defects, improving magnetoresistance ratios, and maintaining the composition integrity of phase change materials, resulting in reliable and high-performance memory devices with improved operational characteristics.
Implementation Method 1
performing a plasma reactive etching process on the etching object layer using an etching gas including at least ammonia (NH3) gas
Implementation Method 2
performing a plasma reactive etching process on the etching object layer using an etching gas including at least ammonia (NH3) gas
Data Source
AI summary
Methods of forming pattern structures and methods of manufacturing memory devices using the same are provided, the methods of forming pattern structures include forming an etching object layer on a substrate and performing a plasma reactive etching process on the etching object layer using an etching gas including at least ammonia (NH3) gas. The etching object layer includes a magnetic material or a phase change material.