Magnetron Rotation Speed Control for Sputtering Uniformity
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Solution Overview
Problem
In sputtering processes, particularly in reactive sputtering, achieving uniform film thickness across substrates remains a challenge due to variations in the magnetic field's movement relative to the target, which affects deposition uniformity and target erosion.
Innovation Solution
Controlling the speed of the magnetic field's movement across the target face to optimize deposition uniformity, with specific speeds between 20 and 500 rpm selected to minimize non-uniformity, and adjusting this speed based on target erosion rates to maintain consistent erosion across the target face.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the magnetic field moves across the target face at high speed, then sputtering efficiency is improved, but deposition uniformity deteriorates
Solution Approach 1:
The patent applies dynamics by making the magnetic field movement speed variable rather than fixed. The magnetron rotation speed is dynamically adjusted during the sputtering process based on real-time monitoring of deposition uniformity, allowing the system to optimize between sputtering efficiency and deposition uniformity as conditions change.
Solution Approach 2:
The patent implements feedback control by monitoring deposition uniformity and using this information to adjust the magnetron rotation speed. The system continuously measures the deposition rate across the target face and adjusts the magnetic field movement speed to maintain optimal uniformity while preserving sputtering efficiency.
2Manufacturing precision
If the magnetron rotation speed is increased to improve deposition uniformity, then film thickness uniformity is improved, but target erosion non-uniformity increases
Solution Approach 1:
The patent uses dynamic adjustment of magnetron rotation speed to balance film thickness uniformity and target erosion uniformity. Rather than maintaining a constant high rotation speed, the system varies the speed during operation to achieve both uniform film deposition and uniform target consumption patterns.
Solution Approach 2:
The patent changes the operational parameters of the magnetron rotation speed during the sputtering process. By adjusting this parameter based on monitored conditions, the system optimizes both film thickness uniformity and target erosion characteristics without sacrificing one for the other.
3Device complexity
If a static magnetron/target assembly is used, then device complexity is reduced, but deposition uniformity deteriorates
Solution Approach 1:
The patent introduces dynamic motion of the magnetic field across the target face by rotating the magnetron, transforming a static assembly into a dynamic system. This relative motion enables uniform deposition across the substrate while maintaining relatively simple device architecture.
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 significantly improves deposition uniformity, as demonstrated by reducing non-uniformity from 1.1% to 0.7% in molybdenum sputtering, achieving a 36% improvement and maintaining optimal uniformity throughout the target's life by dynamically adjusting the magnetron rotation speed.
Implementation Method 1
a magnetron providing a magnetic field that moves relative to the target face
Implementation Method 2
Methods and apparatus for sputtering
Data Source
AI summary
A method of sputtering with sputtering apparatus is for depositing a layer upon a substrate. The apparatus includes a sputter target with a face exposed to the substrate and a magnetron providing a magnetic field that moves relative to the target face. The speed of movement of the field is controlled such that the uniformity of the deposition on the substrate is enhanced. A particular method includes monitoring uniformity verses speed, selecting the speed that gives the preferred uniformity and controlling the field to the selected speed. The selected speed may vary over the life of the target, with increased speeds becoming desirable as the target thins.