Sputtering Shutter Aperture Geometry for Target Contamination Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In sputtering apparatuses with multiple targets arranged at equal intervals, contamination occurs when using a single target for sputtering due to materials emitted from one target reaching and adhering to other targets through the shutter apertures.
Innovation Solution
A sputtering apparatus design featuring a shutter unit with first and second shutters that rotate about an axis, with apertures positioned on virtual circles to minimize contamination by ensuring that the central angles of arcs corresponding to target intervals are equal, allowing for controlled exposure of targets to the substrate while preventing material transfer between targets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple targets are arranged at equal intervals with a double rotary shutter mechanism, then co-sputtering can be performed by simultaneously using multiple targets, but contamination occurs when sputtering is performed by using one target due to materials reaching other targets through the shutter apertures
Solution Approach 1:
The patent applies asymmetry by arranging targets at unequal intervals around the substrate holder, specifically positioning targets at 0°, 120°, and 240° angles. This asymmetric arrangement, combined with the shutter aperture positioning, ensures that when one target is active, the sputtered materials do not reach other targets through the shutter apertures, thereby preventing contamination while maintaining co-sputtering capability.
2Adaptability or versatility
If the shutter apertures are positioned to face multiple targets for selecting targets, then target selection flexibility is improved, but the path for material transfer between targets is created
Solution Approach 1:
The patent applies local quality by positioning the shutter apertures at specific locations that face the substrate but are angled such that they do not provide a direct path between targets. The apertures are located at positions where their lines of sight intersect at the substrate center, ensuring that materials sputtered from one target travel toward the substrate rather than reaching other targets, thus maintaining target selection flexibility while preventing material transfer.
3Device complexity
If targets are arranged at equal intervals, then symmetric arrangement simplifies the shutter mechanism design, but contamination paths are created between targets
Solution Approach 1:
The patent deliberately introduces asymmetry by arranging targets at unequal intervals (0°, 120°, 240°) rather than equal intervals. This asymmetric arrangement, when combined with the specific shutter aperture positioning, breaks the symmetry that would otherwise create direct contamination paths between targets, while still maintaining a relatively simple shutter mechanism design.
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 design effectively reduces contamination on targets by optimizing the positional relationship between shutters and targets, ensuring that materials are directed towards the substrate without adhering to other targets, thereby maintaining target cleanliness during sputtering processes.
Implementation Method 1
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, and a plurality of target holders configured to respectively hold targets
Data Source
AI summary
A sputtering apparatus includes a shutter unit, a plurality of target holders, and a substrate holder which can rotate about an axis perpendicular to a surface on which a substrate is held. The shutter unit includes a first shutter having first and second apertures and a second shutter having third and fourth apertures. The plurality of target holders are arranged on a first virtual circle centered on the axis, with the arrangement intervals between the plurality of target holders on the first virtual circle including at least two types of arrangement intervals.