Sputtering Target Layout for Uniform Magnetic Fields
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Solution Overview
Problem
In sputtering apparatus arrangements around a conveyance chamber, the varying magnetic fields due to non-uniform target positions lead to differences in sputtering characteristics, affecting film formation quality and throughput.
Innovation Solution
The sputtering apparatus is designed with target holders arranged on the vertices of a virtual rectangle inscribed in a circle, with specific distances from the gate valve and shutter units to unify magnetic fields and reduce positional dependencies, allowing for more efficient and uniform sputtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If targets are arranged at vertices of a virtual isosceles trapezoid to fit more deposition chambers around the conveyance chamber, then the quantity of sputtering apparatuses increases, but the magnetic field uniformity deteriorates causing sputtering characteristic differences
Solution Approach 1:
The patent applies asymmetry by arranging four targets at vertices of a virtual isosceles trapezoid rather than a symmetric square configuration. Specifically, the distance between adjacent targets on the gate valve side is made shorter than the distance between targets on the opposite side, creating an asymmetric layout that optimizes space utilization around the conveyance chamber while maintaining controlled magnetic field characteristics
Solution Approach 2:
The patent applies local quality by providing different magnet arrangements for different targets. Each target is equipped with magnets configured according to its specific position in the trapezoidal arrangement, with magnet strengths and positions adjusted to compensate for the asymmetric geometry, thereby achieving uniform magnetic field conditions at each target location despite the overall asymmetric configuration
2Productivity
If the width of sputtering apparatus on the gate valve side is decreased to arrange more apparatuses, then the quantity of sputtering apparatuses increases, but the magnetic field interference from adjacent targets increases
Solution Approach 1:
The patent applies local quality by customizing the magnet configuration for each target based on its specific position and the interference it experiences from adjacent targets. Targets experiencing different levels of magnetic field interference from neighboring targets are equipped with magnets of different strengths and orientations to compensate for these local variations, ensuring uniform sputtering characteristics across all targets despite the compact asymmetric arrangement
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 reduces sputtering characteristic differences and enables more compact apparatus design, enhancing film uniformity and throughput by equalizing magnetic fields across targets, thus improving the arrangement efficiency around a conveyance chamber.
Implementation Method 1
Each magnet is generally arranged such that one pole of the N and S poles is directed in the inside direction of the deposition chamber, and the other pole is directed in the outside direction of the deposition chamber. The magnetic field formed inside the deposition chamber by the magnet arranged on the reverse surface side of each target
Implementation Method 2
a sputtering apparatus which includes a chamber, a substrate holder configured to hold a substrate in the chamber and rotate about an axis perpendicular to a surface on which the substrate is held
Data Source
AI summary
A sputtering apparatus includes a chamber, a substrate holder, first to fourth target holders, a shutter unit, and a gate valve through which the substrate is conveyed. The first to fourth target holders are arranged on vertices of a virtual rectangle having long sides and short sides and inscribed in a virtual circle centered on the axis, the first target holder and the second target holder are respectively arranged on two vertices defining one short side of the virtual rectangle, and a distance to the gate valve is shorter than distances from the third target holder and the fourth target holder to the gate valve.