Plasma Etching Selectivity via Dynamic Power Control
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Solution Overview
Problem
Current plasma etching techniques face challenges in achieving high etching selectivity between materials, which affects the resolution and efficiency of the pattern formation process in semiconductor device fabrication.
Innovation Solution
A plasma etching apparatus and method that includes an etching chamber and a processor to determine and control process conditions, such as unit etching time, to improve etching selectivity by optimizing the etching process conditions for specific material layers, ensuring that only the target material is etched during the designated time while the masking layer remains unetched.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plasma etching power is increased to improve etching speed, then productivity is improved, but etching selectivity between materials deteriorates
Solution Approach 1:
The etching process uses dynamic adjustment of plasma power throughout the etching cycle. High power is applied during etching steps to maximize etching speed, while power is completely deactivated during pause steps to allow selective recovery. This dynamic power adjustment enables the process to achieve high average etching speed while maintaining material selectivity, as the masking layer is exposed to low or zero power during critical periods when it would otherwise be damaged.
Solution Approach 2:
The process utilizes changes in plasma parameters (power, pressure, gas flow) between different steps to control etching selectivity. By varying these parameters dynamically - particularly switching plasma power on and off - the process achieves high etching speed for the target material while preventing excessive etching of the masking layer, thereby maintaining both productivity and selectivity.
2Manufacturing precision
If multiple etching steps are used to improve selectivity, then etching precision is improved, but process complexity increases
Solution Approach 1:
The etching process is segmented into discrete, repeatable cycles consisting of an etching step and a pause step. Each cycle is independently controlled and optimized, allowing the complex requirement of selective etching to be broken down into simple, manageable steps. This segmentation enables high etching selectivity through multiple controlled exposures while keeping each individual step simple, thereby reducing overall process complexity despite achieving high precision through repetition.
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 enhances etching selectivity and maintains stability in the etching process, allowing for higher resolution and efficiency in pattern formation by controlling the etching process conditions to prevent unwanted etching of masking layers, thereby improving the overall semiconductor fabrication process.
Implementation Method 1
plasma etching may be used to form a pattern on or in a substrate
Implementation Method 2
The ionized reaction gas diffuses toward the specimen to enable chemisorption to occur between reactive particles of the plasma and a material surface of the specimen
Implementation Method 3
The ionized reaction gas diffuses toward the specimen to enable chemisorption to occur
Data Source
AI summary
A plasma etching apparatus includes an etching chamber and at least one processor. The etching chamber is configured to support a target therein. The at least one processor is configured to: determine a process condition for plasma etching the target before execution of a plasma etching process; and control an aspect of the chamber according to the process condition. The process condition includes a unit etching time over which the plasma etching process is to be continuously performed.