Dynamic Ion Beam Control for Multilayer Etching
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Solution Overview
Problem
Current substrate etching methods for multilayer structures, such as MRAM devices, face challenges like mask erosion, redeposition of metal residues, and sidewall damage due to the non-volatile nature of materials like Co, Pt, or Fe, leading to performance degradation and limitations in layer stack thickness and critical dimension accuracy.
Innovation Solution
A dynamic etching process using an ion beam with adjustable control settings based on real-time monitoring of material changes through optical emission spectroscopy (OES) or reflectometry, allowing for tailored ion beam incidence angle and energy adjustments according to the specific properties of each layer, ensuring precise etching and minimizing redeposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If physical etching mechanisms are used to etch non-volatile material layers, then etching capability is achieved, but mask erosion occurs and critical dimension accuracy deteriorates
Solution Approach 1:
The patent applies dynamic control of ion beam parameters (energy, angle, current) during the etching process. The system continuously monitors etch depth and material composition, adjusting ion beam settings in real-time to optimize etching for each specific layer while minimizing mask erosion and maintaining critical dimension accuracy.
Solution Approach 2:
The patent changes physical parameters of the ion beam (energy, angle of incidence, current density) according to the specific layer being etched. Different parameter sets are applied for different material layers (e.g., Ru, CoFeB, MgO, Ta) to achieve optimal etching results with minimal mask damage and accurate critical dimensions.
2Manufacturing precision
If ion beam etching is used to etch multilayer structures, then etching capability is achieved, but redeposition of metal residues occurs leading to sidewall damage
Solution Approach 1:
The system dynamically adjusts ion beam parameters during etching to minimize redeposition. By optimizing ion energy and angle for each layer, the process reduces metal residue generation and redeposition on sidewalls, maintaining sidewall integrity and preventing shorting between metal layers.
Solution Approach 2:
The patent employs real-time monitoring of etch depth, material composition, and process conditions. This feedback is used to adjust ion beam parameters dynamically, ensuring optimal etching that minimizes redeposition and protects sidewall integrity throughout the multilayer etching process.
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 approach improves the abruptness and integrity of etched structures by dynamically adjusting ion beam parameters, reducing sidewall damage and redeposition, thereby enhancing the performance and accuracy of patterned features in multilayer devices.
Implementation Method 1
the etching process for patterning an MRAM layer stack mainly relies on physical etching mechanisms
Implementation Method 2
detecting a signal from the substrate that indicates a change in material being etched by the first ion beam from a first material to a second material
Data Source
AI summary
In one embodiment a method of etching a substrate includes directing a first ion beam to the substrate through an extraction plate of a processing apparatus using a first set of control settings of the processing apparatus. The method may further include detecting a signal from the substrate that indicates a change in material being etched by the first ion beam from a first material to a second material, adjusting control settings of the processing apparatus to a second set of control settings different from the first set of control settings based on the second material, and directing a second ion beam to the substrate through the extraction plate using the second set of control settings.