Metal/Alloy Sputtering Targets Manufacturing Technology
views, Updated: 2021-09-27
Since metal targets enable the formation of metal films, fully reacted oxide, nitrides and even exotic carbides and selenides are central to thin-film technology. To meet the demands for high-density, high-performance coatings – there are challenges to the production of metal targets that must be met that influence process control and repeatability. Beyond the extraction, purification, and raw material source technologies, macroscopic failure modes vary as the formation technologies themselves.
When a metal or alloy is well-behaved, it melts evenly, outgases flammable impurities, and allow thermo-mechanical processing to refine the grain structure and minimize residual stress. For these materials, Vacuum Induction Melting (VIM) is the most common and flexible technique for producing viable target plate stock from high purity starting rod, bar, turnings, and foils. The metal or alloy is melted and cast into a target mold. Subsequent thermo-mechanical processing, including hot rolling, annealing, and machining, further refine the structure.
The point at which the target's grain structure influences the process stability is strongly dependent on the sputtering approach, and the number of heat/roll/anneal cycles (rolling schedule). It is also true that different materials and compositions have different thermo-mechanical recipes or may require a hybrid or powder process to yield the most appropriate performance. The powders themselves can be produced from chemical synthesis and grinding, atomization, and RF plasma technology.
For right consolidation, the starting powder density and flow characteristics are critical for a homogeneous product. Care is taken to control voids between particles, which otherwise may survive sintering and increase arcs and contamination. Aside from ultimate density, the most important difference between conventional hot and cold press technologies and cast/rolled targets is the oxygen/absorbed gases associated with the powder's high surface area. Depending on the material, conventional hot pressing densities range from 65% - 99%. The more costly Hot Isostatic Press (HIP) process yields a more consistent 99%+ density product.
AEM Deposition has invested considerable time in completing the most cogent line of sputtering targets for the different thresholds of performance and price. Raw materials control, VIM Casting, and advanced thermo-mechanical processing are perhaps the most notable differences between Ion Beam and Magnetron Sputtering targets. They also impact Optical and Semiconductor grade products.
Hot Pressing creates the best grain structure, but risks from oxygen (for metal mode), anomalous erosion, and particles must be monitored closely. VIM cast and rolled targets offer the advantages of scale, low oxygen, and strength. However, they are limited to well-behaved metals and stable alloys that remain intact after successive thermo-mechanical processing. The intense bombardment and activity of a reactive process cause a host of common failures in targets. For example, fragile metals like Silicon and Germanium can crack. Hard metals like Niobium and Zirconium can deform and de-bond; complex alloys can change composition, melt or become brittle. For these reasons, AEM Deposition uses an ever-growing host of powder and plate manufacturing/handling technologies, plus years of professional expertise in working with thin-film deposition materials to help the industry address challenging applications.
AEM Deposition is an international company involved in manufacturing and selling sputtering targets. Our core products include Pure Metal Targets, Alloy Targets, Oxide Targets, Sulfide Targets, Nitride Targets, Fluoride Targets, Selenide Targets, Boride Targets, Carbide Targets, Silicide Targets, Telluride Targets, and others. If you need sputtering targets, you can click the link to get more detailed information or send an email to us.