Magnet Structure for Uniform Target Erosion in Magnetron Sputtering
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Solution Overview
Problem
The existing magnetron sputtering techniques face challenges in achieving uniform target utilization efficiency due to non-uniform sputtering patterns caused by stronger magnetic fields, requiring complex magnet design and significant trial-and-error efforts to balance magnetic flux densities for effective plasma confinement.
Innovation Solution
A magnet structure comprising inner and outer magnets with different magnetic moment orientations, paired with intermediate magnets and magnetic members to produce a quadridirectional magnetic field, ensuring balanced magnetic flux densities and reducing the number of design parameters, thereby simplifying the magnet design process and enhancing target utilization efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a tunnel-shaped magnetic field is formed to capture secondary electrons and increase plasma density, then film formation rate is improved, but target material is locally eroded faster causing non-uniform sputtering and decreased target utilization efficiency
Solution Approach 1:
The magnet structure is divided into multiple independent magnets (first magnet, second magnet, third magnet, fourth magnet) arranged in a specific pattern. Each magnet contributes to different regions of the magnetic field, allowing the overall field to be segmented into canceling components that prevent localized erosion while maintaining high plasma density for efficient film formation.
Solution Approach 2:
The patent creates different magnetic field characteristics in different regions of the target surface. By positioning magnets with specific polarities (N and S poles) at different locations, the magnetic flux density is locally adjusted to achieve uniform sputtering across the target surface while maintaining high plasma confinement in the sputtering region.
2Loss of substance
If quadridirectional magnetic field is produced using multiple magnets with different orientations, then target utilization efficiency is improved, but magnet design complexity and trial-and-error effort increase significantly
Solution Approach 1:
The magnet structure employs an asymmetric arrangement where magnets are positioned at different locations (first magnet at one corner, second magnet at opposite corner, third and fourth magnets at adjacent corners) with specific polarity orientations. This asymmetric configuration naturally produces the required quadridirectional magnetic field pattern without requiring complex iterative design adjustments.
Solution Approach 2:
Instead of trying to create a uniform magnetic field and then adding corrections, the patent inverts the approach by directly designing a magnetic field structure where opposing magnets create canceling flux components. The N-S-N-S arrangement inherently produces the desired field cancellation effect, simplifying the design process.
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
The proposed magnet structure achieves wide target erosion with suppressed localized sputtering, increasing target utilization efficiency and prolonging target change periods, thus improving the operating efficiency of magnetron sputtering systems.
Implementation Method 1
a tunnel-shaped magnetic field is formed over a target surface to capture secondary electrons generated during a process of the sputtering phenomenon by Lorentz force
Implementation Method 2
capture secondary electrons generated during a process of the sputtering phenomenon by Lorentz force and cause the secondary electrons to conduct their cycloid motion
Implementation Method 3
A film formation method based on sputtering phenomenon in which ion (for example Ar ion) is caused to collide with a target material in a vacuum to cause atoms of the target to pop up from the target material and deposit on a substrate disposed opposite to the target material
Data Source
AI summary
A magnet structure and the like are provided, which can reduce the labor required to make a magnet design for producing a tunnel-shaped leakage magnetic field for plasma confinement in a well-balanced manner over an obverse surface of a target, based on a quadridirectional magnetic field produced by magnetic interaction between plural magnets. The magnet structure (110) includes: inner and outer magnets (10 and 13) positioned at a reverse surface side of a target (20) to have different magnetic moment orientations for producing a first magnetic force line reaching an obverse surface (20A) of the target (20); a pair of intermediate magnets (11 and 12) positioned at the reverse surface side of the target (20) and between the inner and outer magnets (10 and 13) to have different magnetic moment orientations, for producing a second magnetic force line acting to cancel a widthwise magnetic flux density component which is produced by the first magnetic force line; and a magnetic member (24) positioned at the reverse surface side of the target (20) to guide the second magnetic force line emanating from an end surface of one of the pair of intermediate magnets (11 and 12) into an end surface of the other, the magnetic member (24) being configured to produce a magnetic force line reaching an intermediate point in a thickness direction of the target (20) in association with the inner magnet (10) or the outer magnet (13).