Plasma Etching Wafer Inclination Rotation Uniformity
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Solution Overview
Problem
Plasma etching in the manufacturing of magnetic random access memory (MRAM) elements results in uneven etching rates due to deviations in plasma density distribution, leading to compromised wafer quality and manufacturing efficiency.
Innovation Solution
A method involving a plasma processing apparatus that inclines and rotates the workpiece during etching, adjusting inclination angles and process times to achieve uniform etching rates by utilizing predicted distributions of etching rates based on specific inclination angles and conditions, ensuring accurate specification and implementation of inclined rotation states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If plasma etching is performed using a conventional plasma processing apparatus, then the etching process can be completed, but the etching rate becomes uneven across the wafer surface due to plasma density distribution deviations
Solution Approach 1:
The holding structure is designed to rotate during the etching process, dynamically changing the position of the workpiece relative to the plasma source. This rotation ensures that all areas of the workpiece are exposed to relatively uniform plasma density over time, compensating for the inherent non-uniformity in plasma distribution and achieving uniform etching rates across the entire surface.
Solution Approach 2:
The invention changes the operational parameters by introducing rotation speed and inclination angle as controllable variables. By optimizing these parameters, the system transforms a static etching process into a dynamic one where the workpiece continuously samples different plasma density regions, thereby averaging out the non-uniformities and achieving consistent etching rates.
2Manufacturing precision
If the holding structure is inclined and rotated during etching, then the uniformity of etching rate is improved, but the device complexity increases
Solution Approach 1:
The holding structure serves multiple functions: it holds the workpiece, provides rotation capability, and enables inclination adjustment. By integrating these functions into a single multi-functional component, the invention avoids the need for separate mechanisms for each function, thereby reducing overall system complexity while achieving the desired etching uniformity.
Solution Approach 2:
The invention introduces a new degree of freedom by tilting the holding structure at an angle relative to the plasma source. This angular dimension, combined with rotation, creates a conical motion pattern that effectively distributes plasma exposure across the workpiece surface, achieving uniform etching without requiring complex multi-axis positioning systems.
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 significantly improves the uniformity of the etching rate, effectively addressing the issue of uneven etching and enhancing the quality and efficiency of the MRAM element manufacturing process.
Implementation Method 1
a step of etching the workpiece by plasma generated in the processing container
Data Source
AI summary
A method MT includes etching a wafer W using plasma generated in a processing container. The etching includes a process of inclining and rotating a holding structure holding the wafer W during execution of the etching and the process successively creating a plurality of inclined rotation states RT(φ, t) with respect to the holding structure. In the inclined rotation states, the wafer W is rotated about a central axis of the wafer W over a predetermined process time while maintaining a state where the central axis is inclined with respect to a reference axis of the processing container which is in the same plane as the central axis. A combination of a value φ of an inclination angle AN of the central axis with respect to the reference axis and the process time t differs for each of the plurality of inclined rotation states.