Sputtering Target Surface Preparation to Reduce Particulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Sputtering targets often have surface defects from machining processes that lead to high levels of particulation during sputtering, requiring extensive burn-in time to address these issues, which is costly and inefficient.
Innovation Solution
The method involves bead blasting and subsequent surface polishing, cleaning, and annealing to remove defects and residual stress, resulting in a homogeneous, contamination-free surface that reduces particulation and minimizes burn-in time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If mechanical machining steps (grinding, turning, lathing, milling) are used to form the sputtering target with desired dimensions and shape, then manufacturing precision is improved, but surface defects (cracks, contaminations, machining scratches, grinding lines, embedded impurities) are introduced that increase particulation
Solution Approach 1:
The patent applies preliminary surface treatment actions (bead blasting, polishing, cleaning, annealing) after mechanical machining to remove the harmful surface defects before the sputtering process begins. This preliminary action eliminates cracks, contaminations, and machining scratches that would otherwise cause particulation during sputtering.
2Object-generated harmful factors
If a burn-in or preconditioning step is used to remove surface defects prior to material deposition, then particulation is reduced, but production time is lost and operational efficiency decreases
Solution Approach 1:
The patent performs all necessary surface defect removal and surface quality improvement actions (bead blasting, polishing, cleaning, annealing) as preliminary steps before the sputtering target is installed in the sputtering chamber. This eliminates the need for burn-in or preconditioning steps during production, as the surface is already optimized for low particulation from the outset.
Solution Approach 2:
The patent skips the traditional burn-in or preconditioning step entirely by rushing through all necessary surface preparation actions before target installation. The comprehensive pre-treatment approach allows the process to move directly from surface preparation to production sputtering without intermediate conditioning phases.
3Object-generated harmful factors
If extensive burn-in time is allocated to remove surface defects, then surface quality is improved, but time cost and operational expense increase
Solution Approach 1:
The patent performs all surface defect removal actions (bead blasting to remove cracks and contaminations, polishing to eliminate machining scratches, cleaning to remove embedded impurities, and annealing to address residual stress) as preliminary steps before the target enters production use. This shifts all time investment to the preparation phase, eliminating ongoing burn-in time requirements.
4Object-generated harmful factors
If multiple surface treatment steps (bead blasting, polishing, cleaning, annealing) are applied, then surface quality and homogeneity are improved, but process complexity increases
Solution Approach 1:
The patent segments the surface treatment process into distinct sequential steps, each addressing specific surface defects: bead blasting for cracks and contaminations, polishing for machining scratches, cleaning for embedded impurities, and annealing for residual stress. This segmentation allows each step to be optimized independently while achieving comprehensive surface quality improvement.
Solution Approach 2:
The patent uses intermediary substances and processes between each treatment step: blasting media for bead blasting, polishing compounds for polishing, cleaning solutions for cleaning, and controlled atmosphere for annealing. These intermediaries facilitate each transformation while protecting the target material.
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 process significantly reduces particulation and burn-in time, enhancing the efficiency and cost-effectiveness of sputtering operations by producing a defect-free, residual stress-free sputtering target surface.
Implementation Method 1
The sputtering target is then bombarded with a beam of energetic particles (e.g., an ion beam or a plasma beam) in a controlled environment. Atoms of the source material are ejected from the sputtering target and deposited onto the substrate to form a thin film
Implementation Method 2
Finally, the target can be annealed to remove the surface residual stress
Data Source
AI summary
Methods for finishing a sputtering target to reduce particulation and to reduce burn-in time are disclosed. The surface of the unfinished sputtering target is blasted with beads to remove machining-induced defects. Additional post-processing steps include dust blowing-off, surface wiping, dry ice blasting, removing moisture using hot air gun, and annealing, resulting in a homogeneous, ultra-clean, residual-stress-free, hydrocarbon chemicals-free surface.