Materials Processing

3-D printing has potential to revolutionize manufacturing of customized low-cost scientific equipment, and numerous self-designed applications have already been realized and demonstrated. However, the applicability of 3-D printed devices to cleanrooms used for semiconductor processing is not as straightforward, as the controlled environment sets strict requirements for the allowed materials and items. This work investigates the opportunity to utilize 3-D printing in cleanrooms by analyzing three potentially suitable polymers (polylactic acid (PLA), acrylonitrile butadiene styrene (ABS) and polypropylene (PP)) for two applications that do not require particular chemical compatibility: a custom single wafer storage box and a wafer positioner for a metrology system. The designed equipment supplements commercial selection by introducing support for samples with non-standard shape or size and simultaneously reduces the price of often extensively expensive cleanroom equipment. The results show that the single wafer boxes 3-D printed from PLA and ABS generate as little particles as a commercial equivalent, whereas slightly more particles are found from a wafer stored in the self-printed PP box. Nevertheless, the number of particles on all wafers is in the same order of magnitude, indicating that 3-D printed boxes are not significant particle sources. The 3-D wafer positioner seems to cause a negligible particle increase on the manipulated wafer, while abrasion of the mechanical parts generate larger numbers of particles that may disperse in the environment. Regular cleaning of those parts is thus recommended, and applicability in a cleanroom environment will depend on the cleanliness constraints. Elemental analysis reveals that 3-D printed objects contain no other harmful metal impurities than those originating from colorants. Thus, 3-D printing filaments with natural color should be preferred for purposes, where metal contamination could be an issue, including semiconductor processing. Finally, 3-D printing filaments considered in this study are shown to be resistant to isopropanol and deionized water, which is critical for efficient cleaning for use of 3-D printed objects in cleanrooms. The results demonstrate that simple 3-D printed objects, such as wafer boxes or tweezers, are not notable contamination sources, and hence, are equally suitable for use in cleanrooms as the commercial equivalents.

The metal 3-D printing market is currently dominated by high-end applications, which make it inaccessible for small and medium enterprises, fab labs, and individual makers who are interested in the ability to prototype and additively manufacture final products in metal. Recent progress led to low-cost open-source metal 3-D printers using a gas metal arc welding (GMAW)-based print head. This reduced the cost of metal 3-D printers into the range of desktop prosumer polymer 3-D printers. Consequent research established good material properties of metal 3-D printed parts with readily-available weld filler wire, reusable substrates, thermal and stress properties, toolpath planning, bead-width control, mechanical properties, and support for overhangs. These previous works showed that GMAW-based metal 3-D printing has a good adhesion between layers and is not porous inside the printed parts, but they did not proceed far enough to demonstrate applications. In this study, the utility of the GMAW approach to 3-D printing is investigated using a low-cost open-source metal 3-D printer and a converted Computer Numerical Control router machine to make useful parts over a range of applications including: fixing an existing part by adding a 3-D metal feature, creating a product using the substrate as part of the component, 3-D printing in high resolution of useful objects, near net objects, and making an integrated product using a combination of steel and polymer 3-D printing. The results show that GMAW-based 3-D printing is capable of distributed manufacturing of useful products for a wide variety of applications for sustainable development.