Modeling and validation of uniform large-area optical coating deposition on a rotating drum using microwave plasma reactive sputtering

Abstract

Magnetron sputter deposition onto a rotating drum is a method applied to high-throughput large-area optical coating deposition, where film physical thickness uniformity is an important parameter. Techniques have been developed, such as masking/substrate movement, in order to improve sputtered film uniformity. In this study, a model is described and validated for predicting film uniformity. Experimental data show excellent agreement with modeled simulations, with and without a modified sputtering mask. Practical application is demonstrated in maximizing uniformity over an individual substrate size of 100 cm² for a high-optical-density visible/near-infrared dual-band laser protection filter.

Simulation and Optimization of Film Thickness Uniformity in Physical Vapor Deposition

“…Or for the small surface source, integration of the point source through the small area is required, thus bring Equation (22) into Equation (9) to get:…”

“…As shown in the flow chart ( Figure 26) the sputtering yield at coordinates of any point ( , , ) of the target are related to the magnetic field distribution. For convenience, it is obtained by measuring the sputtering erosion track profile of the target, as shown in Figure 27; the details of measurement were given by Li et al [22]. Due to the rotation of Then the shape of the mask is defined, Figure 28b, and the contribution of all points of the target is summed over the range of the substrate rotation angle (−β 0 , β 0 ) to obtain the final film thickness distribution equation.…”

“…These factors include: substrate holder geometry, vacuum pressure, system temperatures (i.e., substrate and material flux temperatures), and angular configuration of the deposition material to the substrate [15]. Separate studies of these factors were carried out by various researchers: the emission characteristics of evaporation sources were summarized by Aaron and Charles [16]; film thickness distributions of the flat plate, spherical surface and planetary substrate holders of evaporation sources were investigated in [17][18][19][20][21]; the parameters for sputtering PVD systems were studied by [14,[22][23][24]; and Villa et al and Hsu [25,26] studied and simulated mask designs for thin film depositions, particularly for sputtering depositions. However, there has yet to be a systematic review of techniques, methods, and modelling theories for producing higher uniformity coatings in PVD systems.…”

Miniaturised Infrared Spectrophotometer for Low Power Consumption Multi-Gas Sensing

“…Linear variable filters (LVF) are spatially variable optical band pass filters, in which the center wavelength changes with position in a linear manner along one direction of the filter. The LVF used in this work was fabricated at the University of the West of Scotland using a unique and volume-scalable technology [32][33][34]. The manufactured LVF has a spectral range of 2.9 to 4.8 µm with a pass band width of 1.5%.…”

Optimised Performance of Non-Dispersive Infrared Gas Sensors Using Multilayer Thin Film Bandpass Filters

“…Work has previously been carried out by Cheng et al [28], evaluating the coating thickness uniformity using the microwave plasma-assisted sputtering technique used in this work. In this work, the LED/PD bridgeboards were mounted onto specially designed toolings with precision masking, permitting application of the BPF coating to the photodiode surface area only, however, this method may not be optimal for scalable mass production of coated photodiodes.…”