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AlO_x has long been touted as a suitable transparent layer for packaging applications & has indeed found use in a range of retort applications based on high performance PET substrates. However, the drive towards sustainable packaging solutions utilizing a polyolefin “mono-material” architecture has resulted in an increased desire to use softer, reduced stiffness substrate materials. Standard reactive evaporation of these AlO_x thin films can no longer be used to deposit high quality, mechanically resilient coatings capable of surviving downstream converting at high yield. Alternative substrate engineering techniques and/or AlO_x deposition technologies are therefore required to compensate for these effects. This paper describes the use of an engineered BOPP substrate in combination with a high-density plasma assisted AlO_x deposition technique and focuses on the fundamental differences in mechanical and resultant barrier performance levels achievable with both the standard reactive deposition and plasma assisted deposition approaches. Conclusions are also provided indicating the inherent suitability of the plasma assisted approach for high yield high performance transparent barrier solutions required for the next generation of sustainable packaging.

https://doi.org/10.14332/svc23.proc.0058

Electron beam physical vapor deposition (EB-PVD) with high power axial EB guns allows for high coating rates and therefore it is predestinated when comparatively thick coatings shall be deposited with high throughput in mass production processes. The top sliding layer on bearing shells is an excellent application case. In low-cost manufacturing technologies, often semifinished products such as sheets or strips are coated, from which the final products are manufactured which can exhibit quite a broad range of dimensions.

The adaptation of related processes such as pretreatment and substrate cooling of three different semi-finished products was the focus of the investigations. All process steps were optimized for high throughput. The depositions with AlSn or AlSnCu alloys were carried out at coating rates up to 1 μm/s.  These alloys with components of different vapor pressures were evaporated out of one continuously fed crucible with long-term stability. 

The layers revealed a very fine distribution of tin clusters in the aluminum matrix. The tin clusters had dimensions in the range of 200 to 400 nm. This grain size range was a direct consequence of the high coating rate; it is thus process-specific for EB-PVD. Such coatings are highly beneficial for applications such as plain bearings. Initial stress tests have impressively confirmed the advantages for EB-PVD processed bearings.

https://doi.org/10.14332/svc23.proc.0054

More than 60% of all product innovations are based on the development of new and improved high-performance materials, which requires continuous optimization of associated production technologies and manufacturing processes. Coatings by physical vapor deposition (PVD), chemical vapor deposition (CVD) and plasma-assisted CVD (PACVD) are in many cases essential to increase productivity and to ensure excellent product quality while minimizing production downtime and scrap rate in forming and molding tool applications.

Increased lightweight design, improved fuel economy and robustness in modern vehicles are the key drivers for the continuous development of new materials and make the automotive sector a prime example utilizing press hardened steels (PHS), martensitic and multi-phase ultra-high strength steels (UHSS), dual phase advanced high strength steels (AHSS) and aluminum alloys in the automotive body.

The associated forming applications cover a broad stress profile that results in complex demands on the coated forming tools. This includes a high resistance to impact fatigue and crack formation under cyclic loading as well as a high resistance to abrasive and adhesive wear.

One encouraging way of forming these highly demanding materials is to reduce the frictional forces between the die and the workpiece material such that the optimum material flow during the forming operation is achieved. A promising approach is to set the optimum friction state, (while minimizing costly and environmentally harmful lubricant usage), by incorporating the lubrication properties into the PVD or PACVD coating.

This paper deals with the investigation of the potential of hard coatings with reduced frictional properties for industrial forming applications. Three different lubricant concepts in the as-deposited state are discussed, including solid lubricants with layer-lattice structure, such as sulfides (MoS₂), diamond-like carbon (DLC), as well as oxides. Current research and development needs and the preferred coating solutions are introduced based on the performance in field tests at Ionbond^TM's customers.

The wide gap between basic analysis of the coating solutions and time- and cost-intensive field tests at customers’ sites is closed by application-oriented model tests. Results from an impact fatigue tester simulating the kinematics in metal sheet forming demonstrate the importance of plasma nitriding to improve the load-carrying capacity for the follow-up PVD coating. The improved impact fatigue behavior of such duplex coatings also reflected in improved performance in the forming application.

https://doi.org/10.14332/svc23.proc.0051

Quantum device performance losses are predominantly from surfaces and interfaces. In diamond and SiC-based quantum sensors, for example, surface and interface defects lead to reduced spin coherence times (T2) and zero phonon line (ZPL) emission spectral diffusion. Atomic layer deposition (ALD) and  atomic layer etch (ALE) enable precise engineering of materials and interfaces to minimize these losses.

Conventional etching techniques, while sufficient for many classical applications, suffer from amorphization, Ar ion implantation, and reactant diffusion in the first 3-7 nm of etched interfaces. This damaged region, also called the selvage layer, is a source of unwanted interactions and losses. Atomic Layer Etch (ALE) offers three key advantages for quantum sensor fabrication: (1) surface smoothing, (2) precise etch rate, and (3) reduced selvage layer depth.

Atomic layer deposition (ALD) is particularly well-suited for sensor devices requiring thin, uniform, and reproducible superconducting films with tunable properties, such as superconducting nanowire single photon detectors and kinetic inductance-based sensors.

We will introduce ALD and ALE and discuss specific processes and use-cases for quantum sensor device fabrication, including work conducted with our global network of academic partners and collaborators.

https://doi.org/10.14332/svc23.proc.0057

Deposition of thin films involves in many cases plasma-based processes. The compositional real-time analysis of plasma is readily available by employing the spectroscopic plasma monitoring technique based on optical emission spectroscopy (OES) in the UV/VIS/NIR range. This plasma monitoring technique is well known and widely used in the industry for diagnostic and control purposes. On the other hand, in-situ measurements of the reflectivity of a growing thin film can be used to determine the film thickness and thus is crucial in determining the endpoint of a coating process.

In this work we used both methods to simultaneously monitor the plasma composition as well as the thin film reflectivity. The growth of nanocrystalline diamond (NCD) thin films on silicon (Si) substrates in a linear antenna microwave plasma-enhanced chemical vapor deposition (LA MW PE CVD) reactor was observed. Those films are envisioned to be used as protective coatings in optical coating stacks, due to their very good mechanical properties with respect to scratching and wear. However due to the nanocrystalline nature of the films the surface tends to exhibit significantly higher roughness than amorphous films typically used for optical coatings. One of the questions covered in this work is whether in-situ reflectometry can provide reliable information about the film properties in the presence of significant surface roughness.

https://doi.org/10.14332/svc23.proc.0048

US ITER is the domestic agency participating in the development of the ITER experimental fusion reactor, which is currently under construction. Included in the work scope of US ITER is support for the diagnostic instrumentation that will make measurements during plasma discharges for fusion research. Within this organization, optical analytical techniques are being evaluated and tested in a plasma diagnostics lab at the Oak Ridge National Laboratory – Fusion Energy Division. Specifically, US-ITER is tasked with developing an optical emission technique that has sufficient sensitivity to resolve the emission lines of the gas species in the region of interest, which includes hydrogen and helium isotopes with gas concentrations as low as one percent for specific species. To achieve this capability, ORNL is evaluating various plasma sources and optical emission spectrometer (OES) capabilities, collectively referred to as optical gas analysis (OGA). This instrumentation is both available commercially and is being developed as an R&D effort, with the goal to determine which combination of components realizes the most optimal system. Ultimately, the final concept will produce an OGA system that will be a valuable resource for fusion energy applications. This talk will discuss an overview of the recent development of OGA technology at ORNL for ITER.

https://doi.org/10.14332/svc23.proc.0046

Process monitoring is one of the key elements in modern product manufacturing. The knowledge of the product quality at any stage of the production cycle allows the adjustment of further processing steps and helps to prevent defects and over-processing. Thus, the product yield increases whereas costs and required resources decrease.

This poster introduces a novel concept in in-tool electrical characterization of conductive layers deposited by PVD vacuum technology. A non-contact eddy current sensor, directly installed in a heated vacuum process chamber, provides early-stage detection. It measures the electrical resistivity during the post-annealing step of AZO-layers in a simulated coating production cycle and controls their annealing time. In order to ascertain the applicability of the sensor under pilot-scale conditions, reproducibility and influence of certain process parameters (e.g., heater temperature and film thickness) on the process stability were investigated.

https://doi.org/10.14332/svc23.proc.0045

A chalcogen sensor has been developed, aimed at the monitoring and control of oxygen (O), sulphur (S) and selenium (Se) gas phases in deposition processes.

The sensor has been implemented in an oxide reactive sputtering oxygen feedback control showing the efficiency and advantages that it presents with respect to other methods of sensing.

It has also been implemented as sulphur sensor in a magnetron sputtering (MS) enhanced sulphur thermal sublimation process. The results suggest that it can be implemented as sulphur sensing method for the deposition of sulphides and selenides with a high capacity of recovery under process contaminations.

The results obtained in both processes show the importance of finding an adequate and specific method of sensing in MS to avoid system failures, maximize outcome and reduce waste. They also show that this sensor represents a suitable alternative for sensing chalcogen species as it is independent of external factors what makes it easy to implement as a standard method.

https://doi.org/10.14332/svc23.proc.0061

Nowadays, almost all coating machines for high precision optical interference filters include at least one kind of monitoring which can be based on broad band or single wavelength transmittance or reflectance measurement. The Modular Optical Coating Control Application (MOCCA+) was developed at the Fraunhofer IST for turntable metamode sputtering machines (e.g. EOSS) and includes an interface to the programmable logic controller. All material recipes and stack procedures are stored in a database. Thus, the user does not need to do any further scripting at the user interface of the machine. This helps for quick product feature changes. Once defined a coating batch, only the substrates need to be loaded into the vacuum transfer magazine. From the handling into the machine the process is fully automated up to the final measurement to check the products. We show in situ high resolution characterization including thermal effects on the realized spectra.

The techniques that are used in optical monitoring software may also be transferred to other types of coating machines and adapted to customer needs. Only the sensor changes but the algorithms for security and reinitialization after shutdowns remain the same. Due to the modular structure, e.g. ellipsometry, quartz crystal or plasma optical emission spectroscopy can be integrated. Multi-channel OES measurement and data evaluation along the coating process will be presented. Plasma conditions during different situations like shutter movements and material changes are evaluated up to end of lifetime detection of sputter targets.

Digitizing the whole process chain in one software package allows for data mining and machine learning. The analysis results of measurements connected with machine parameters allow for a closed loop. Thereby, the software can learn during the coating e.g., the actual deposition rate if further layers are deposited by time or is able to include spectral shifts into the calculation.

https://doi.org/10.14332/svc23.proc.0047

Developments in reactive magnetron sputtering processes have unlocked great possibilities in controlling film stoichiometry and properties. For some material/reactive gas combinations, it is crucial that the reactive gas flow is regulated via a closed-loop feedback system, able to capture the system status and adjust the reactive gas input at any given time. The plasma discharge voltage, or target voltage for simplicity, is a good, easily accessible indicator of the process status, and can be used as a sensor for the feedback loop regulating the reactive gas. In some circumstances, notably when a complex dependency between reactive gas flow and target voltage is present, the latter is not enough to unambiguously define a certain process state.

In this work we present two methods to overcome those uncertainties. The first proposed solution relies on the availability of an additional low-cost sensor able to provide extra information to the control mechanism. The second solution involves the development of a mathematical model capable of simulating the process in real-time and delivering the additional data to the feedback loop. Both approaches are presented, along with a discussion of their advantages and limitations.

As a demonstrator system, the reactive magnetron sputtering of stainless-steel oxide from a metallic stainless-steel target is studied.

https://doi.org/10.14332/svc23.proc.0060