Sputtering Target with Annular Grooves for Uniform Erosion
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Solution Overview
Problem
Sputtering targets in sputtering chambers often exhibit uneven cross-sectional thickness and surface profiles due to variations in plasma density, magnetic field geometry, and grain size, leading to premature target erosion and contamination of substrates.
Innovation Solution
A sputtering target design featuring a backing plate with strategically positioned annular grooves and circular ridges, made from different materials, to manage erosion and eddy currents, ensuring uniform sputtering and extended target life by providing additional sputtering material and altering electromagnetic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional sputtering target is used, then the sputtering process can proceed, but the target develops uneven cross-sectional thickness and surface profile due to variations in plasma density and magnetic field geometry, leading to premature target erosion and contamination
Solution Approach 1:
The patent applies local quality by creating non-uniform material composition within the target. The target comprises a first material in a first region and a second material in a second region, with different average grain sizes. This local variation in material properties compensates for the non-uniform sputtering rates caused by plasma density and magnetic field variations, maintaining overall surface profile uniformity and extending target life.
2Reliability
If the target is removed before depressions become too deep, then substrate contamination is prevented, but a large portion of the target thickness remains unused
Solution Approach 1:
The patent changes the material composition parameter within the target by incorporating regions with different average grain sizes. The finer-grained regions are strategically positioned to compensate for areas experiencing higher sputtering rates, allowing the target to maintain uniform surface profile and extend usage depth before depressions become problematic, thereby reducing waste of target material.
3Manufacturing precision
If the target material has variable grain size structure, then sputtering uniformity can be improved, but the target structure becomes more complex
Solution Approach 1:
The patent employs composite materials by combining two different materials with different average grain sizes within the same target. The first material with a first average grain size and the second material with a second average grain size are positioned in different regions to create a composite structure that achieves uniform sputtering while managing the complexity through strategic material placement.
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 design achieves longer process life, reduced contamination, and improved sputtering uniformity by extending the target's usage time and maintaining a consistent deposition thickness across substrates.
Implementation Method 1
The sputtering target is bombarded by energetic ions formed in the energized gas causing material to be knocked off the target and deposited as a film on the substrate
Implementation Method 2
The sputtering chamber can also have a magnetic field generator that shapes and confines a magnetic field about the target to improve sputtering of the target material
Implementation Method 3
Uneven target sputtering can arise from variations in localized plasma density caused by the chamber geometry, the shape of the magnetic field about the target, eddy currents induced in the target, and other factors
Data Source
AI summary
A sputtering target for a sputtering chamber comprises a backing plate with a sputtering plate mounted thereon. In one version, the backing plate comprises a circular plate having a front surface comprising an annular groove. The sputtering plate comprises a disk comprising a sputtering surface and a backside surface having a circular ridge that is shaped and sized to fit into the annular groove of the backing plate.