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OCTOBER 2021 I SMT007 MAGAZINE 49 assemblies, subassemblies, and devices are placed inside the equipment's cham- ber where a protective coating is applied as a vapor, forming the protective con- formal coating, measuring thinner than a human hair. The Coating Process e first steps of the HZO process with a potential customer involve a de- tailed evaluation of the product, where the coating process can be introduced in the production flow, and what protection lev- el the customer needs. is evaluation consid- ers the components that require protection and the level of protection required, whether splash resistant, sweat proof, submersible, sol- vent or corrosion resistance, or operating tem- peratures and environment. A detailed process plan is developed, and prototype runs occur to test environmental performance and reliability of the coated customer parts. ere are three distinct steps in the HZO process: pre-process, coating, and post-pro- cess. Pre-process Because CVD coating vapor can pene- trate micron-sized gaps, masking may be re- quired for areas of the PCBA or component that should not be coated, such as screens, sen- sors, lenses, connectors, and other compo- nents whose functionality may be hampered by coating. Much of HZO's intellectual proper- ty is based on innovative materials and process- es designed to streamline the masking process, whether for manual masking, semi-automated masking, or seamless automated masking. Its masking products and solutions are unique and not found anywhere else in manufacturing. Coating Once the masking process is completed, if applicable, products are ready to be coated within the large, efficient cubic coating cham- bers. Custom tray configurations ensure high throughput and safe handling of the product. ey are then placed on racks inside the coat- ing chambers where the coating process com- mences. Parylene coating is applied as a single ma- terial application. e parylene raw material, which is a powder form, is added to a vaporiz- er and sublimed from a solid to a vapor form. e vapor, which is a non-reactive dimer ini- tially, passes into a higher temperature pyro- lyzer, "cracking" the raw material into two ac- tivated monomer units. e coating chamber is under vacuum at room temperature, allowing the vapor to dis- perse evenly in the chamber. e monomer can flow under and around components before polymerizing, creating a uniform, thin-film polymer barrier around the electrical compo- nents being coated. Post-process Aer coating, which can take several hours, parts can be removed from the chamber ful- ly protected—there is no curing or waiting time with parylene. Masking materials are re- moved, and parts are inspected to ensure coat- ing is where it needs to be (and nowhere else). Coating thickness can be verified with an opti- cal measurement and has very tight batch-to- batch and part-to-part repeatability. HZO can also work with multi-layer materi- al coating applications by depositing specific materials on top of one another. is results in unique, strong, and long-lasting coatings that

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