Divide and conquer. It's true in war, and it's also good advice for machine building. Any seemingly insurmountable project often can be busted up into approachable, workable pieces. Dividing machines, production lines, related equipment and accessories into standardized sections and blocks not only simplifies overall system construction, it more importantly improves their operation by allowing much quicker changeovers and maintenance for increased throughput.
Extreme Thin Film
For instance, 20 nm geometries and film depositions that are just two to four atomic layers thick push semiconductor manufacturers to combine more process steps in a vacuum environment. Consequently, Applied Materials in Santa Clara, Calif., is hooking up and pumping the air out of more of its wafer-handling mainframe chambers, robotic interfaces and 40 different reactor units.
"Films are getting thinner, and so they're even more sensitive to impurities or oxidization," says Mike Rice, vice president and general manager of Applied's Foundation Engineering division. "As a result, we now have more sequence chambers that must be under vacuum. Users also are applying eight or 10 layers on some microprocessors, where they once applied just two or three, so they need even faster and more precise tools that can complete 20–40 recipes for particular steps."
Three to nine reactors usually are arranged around Applied's Endura mainframe, and they carry out many of the intra-tool, sequential processing steps required to manufacture semiconductor chips, especially those that can't be exposed to atmosphere (Figure 1). In recent years, these mainframe and reactor modules have been designed to conform to increasingly strict mechanical, electrical and software standards, so any chamber can be located next to any other. This uniformity is crucial because Applied Materials typically ships wafer-handling machines just a month after they're ordered, and then assembles and has them running a month after delivery.
Many aspects of modular machine building are enabled by fieldbuses and Ethernet flavors of networking that simplify cabling by replacing former point-to-point wiring, and by servo motors, amplifiers, drives and controls that remove much of the traditional need for dedicated and less flexible cams, chains and belts. However, just as it's crucial to evaluate the need for automation itself, it's equally important to determine if modularization will deliver enough return on investment (ROI) for individual machines or processes.
"To us, modularity means starting with a base packaging machine and our common bill of materials (BoM) with standard modules that define standard equipment and parts, and then bringing other BoMs into the machine for voltage components, PLC types and different stations and options, such as cappers and film functions," says Scott Bivens, electrical engineering manager at Oystar North America in Covington, Ky., and Davenport, Iowa. "It's a lot like building a pizza. With our modularity, all our designs, BoMs and programs are tested and saved until they're needed. Then, when a particular project order comes along, we can run through a check sheet, and get most of the engineering in place within eight to 10 hours. Traditional, non-modular building means just redoing or copy building a machine that's been done before, and then adding or subtracting required functions. However, because it's not standardized, copy building can take 24–160 hours to do the engineering, depending on the project."
While modular methods help builders design and construct their machines, they're even more beneficial to users. For instance, many production lines and material-handling systems typically used conveyors in 200 ft sections, each with a continuous belt or chain running throughout, and each driven by a 480 V or similar motor.
"Over the years, we grew up with old conveyors that were oily, dirty and difficult to reuse because they were customized for specific applications," says John Dillon, division president of control solutions at Wynright in Elk Grove Village, Ill., which operates its Automotion division in Oak Lawn, Ill. "To gain more flexibility, we developed our AutoRoll+ conveyor that uses motor-driven rollers (MDRs). This technology embeds the conveyor motor in the rollers, so we can localize both the controller card and power into 5 ft zones in the conveyor. This gives our end users modular conveyor beds that we can program, plug and play like Legos, and daisy chain in straight and curved sections. This also creates a highly sustainable solution because they run at 24 V, have fewer moving parts, and are inherently safe."