Magnetic Anode for Rotary Sputter Magnetron
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Solution Overview
Problem
Rotary magnetron sputtering of indium tin oxide (ITO) struggles to achieve the desired optical and electrical film properties due to a weak magnetic plasma confinement field, which results in lower particle arrival energy and film quality, as opposed to the better performance achieved with planar magnetron sputtering.
Innovation Solution
The implementation of magnetic anodes outside the rotary magnetron target tube, made of mild steel or high permeability materials, to enhance the magnetic field strength to 1000 G or more, maintaining a small plasma lobe separation angle and preventing secondary plasma formation, while using larger magnets inside the target tube without increasing the target tube diameter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If bigger magnets are used inside the rotary magnetron to strengthen the magnetic field, then the magnetic field strength is improved, but the plasma lobe separation angle increases and film quality deteriorates
Solution Approach 1:
The patent introduces magnetic anodes positioned radially outward from the target tube, adding a new spatial dimension for magnetic field generation. This external magnetic anode configuration allows field strengthening without increasing the internal magnet size, thereby maintaining small plasma lobe separation and film quality while achieving the desired magnetic field strength.
Solution Approach 2:
The magnetic anodes act as intermediary elements that mediate between the internal magnets and the plasma. By positioning ferromagnetic anodes radially outward, they concentrate and direct the magnetic field lines toward the target surface, achieving field strengthening without the adverse effects of simply enlarging internal magnets.
2Strength
If larger magnets are placed inside the target tube, then the magnetic field strength increases, but the plasma flux distribution becomes less efficient and particle arrival energy decreases
Solution Approach 1:
The patent moves the magnetic field generation to a radial dimension outside the target tube. By placing magnetic anodes on the outer surface, the magnetic field is strengthened without increasing the internal magnet size, thereby maintaining optimal plasma flux distribution and particle arrival energy while achieving the desired field strength.
3Strength
If the target tube diameter is increased to accommodate larger magnets, then the magnetic field strength is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent implements a nested configuration where magnetic anodes are positioned on the outer surface of the existing target tube, wrapping around the plasma racetrack. This nested arrangement allows magnetic field strengthening without increasing the target tube diameter or requiring internal magnet enlargement, thereby maintaining simple device geometry and manufacturing feasibility.
4Manufacturing precision
If stronger magnetic fields are used to improve ITO film properties, then the conductivity and optical properties are enhanced, but the plasma confinement becomes less stable and secondary plasma forms
Solution Approach 1:
The patent applies local quality enhancement by positioning magnetic anodes specifically at regions where plasma confinement is needed. The ferromagnetic material concentrates magnetic field lines locally at the target surface, providing strong fields for ITO quality improvement while maintaining overall plasma stability through localized rather than uniform field enhancement.
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 configuration maintains or improves the ITO film properties comparable to planar magnetron sputtering, enhancing deposition uniformity, increasing particle energy and density on the substrate, reducing contamination, and increasing target material efficiency.
Implementation Method 1
The implementation of magnetic anodes outside the rotary magnetron target tube, made of mild steel or high permeability materials, to enhance the magnetic field strength to 1000 G or more
Implementation Method 2
magnetic anodes outside the rotary magnetron target tube, made of mild steel or high permeability materials
Implementation Method 3
maintaining a small plasma lobe separation angle and preventing secondary plasma formation
Implementation Method 4
Rotary magnetron sputtering of indium tin oxide (ITO)
Data Source
AI summary
A rotary sputter magnetron assembly for use in sputtering target material onto a substrate is provided. The assembly comprises a longitudinally extending target tube having a longitudinal central axis, said target tube extending about a magnet array that is configured to generate a plasma confining magnetic field adjacent the target tube, said target tube supported for rotation about its longitudinal central axis and a pair of side shunts positioned parallel to the longitudinal central axis, and on opposing lengthwise sides of said target tube.