EF Precision Design (Willow Grove, PA) is a division of the EF Precision Group, a machine design and engineering firm that is known for its adherence to the highest standards for precision, quality, and innovation. EF Precision Design ’s products and services are ultimately used by some of the best-known companies in the semiconductor and biomedical industries. Recently they were called upon to automate a Plasma Cleaner. The system was developed by EF Precision Design in conjunction with their West Coast partner, and is used by end customers such as Lucent Technologies to automate cleaning of network chips. EF Precision Design chose Control Technology Corporation's rack style automation controller and touchscreen display to make the cleaning system automated enough to run in a "lights-out," or virtually unattended, operation. Because the machine can receive electronic components in transport carriers, called magazines, that are native to other manufacturing equipment, it can be robotically loaded from another system. A post-cleaning output buffer can store the cleaned components until they too can be transported robotically to the next step in electronic device assembly.

Automating the cleaning process saves labor, and it also saves time. While a skilled technician can clean one full magazine of components in ten to fifteen minutes, the automated plasma cleaner can clean two magazines in less than five minutes. The components are then ready for further assembly, with no additional rinsing or other cleaning required. Manual cleaning is a tedious job that must be done correctly for the components to work well in the final assembly, so automating this job was well received by technicians and plant managers alike. And because the EF Precision design is based on plasma technology, it uses inexpensive gases that have little or no toxicity, so that the costly OSHA and EPA precautions associated with traditional cleaning agents are not required.

The cleaner receives the filled magazines, either robotically or manually, from another process, typically snap curing (a procedure that fixes electronic components to a matrix such as a ball grid array). The magazines ride on a belt drive and stop in front of the cleaning chamber, where a leadscrew and docking plates precisely position the transport magazine end-to-end with a specially designed cleaning magazine that is located inside the chamber. An input system gently pushes the components from the transport magazine to the cleaning magazine, and the chamber doors close. The actual cleaning is ready to start.

Inside the closed chamber, a vacuum removes the ambient air and a pump introduces an excited gas (plasma), such as air, argon, or nitrogen, at a controlled rate and direction. As the gas bombards the components, contaminants dislodge from the surface and break down into gases such as carbon dioxide or water vapor, which are swept away by the effluent stream of gas. The customer can choose a gentle, electron-free cleaning cycle for sensitive components such as CMOS (complementary metal oxide semiconductor) and RF (radio frequency) devices, or an aggressive cycle for more robust components such as bare leadframes and ball grid arrays (BGAs).

About forty seconds later, the cleaned components are ready to leave the chamber. An output pusher slides the components back onto the same transport magazine, which then moves to the output buffer, ready for the next step in production.

The CTC controller ties all of the motion and parameter control functions together. Servo motors, a stepper motor, chamber door interlocks, pumps, and flow/pressure control I/O are very different types of hardware that typically require several different controllers. With CTC, EF Precision Design was able to integrate everything into a single rack style controller, where multitasking logic developed in CTC's Quickstep™ language ensures that the operations of all the different devices work together. Because the code is intrinsically modular, one device's motion can be refined at a discrete point in the code, independent of the code that controls the rest of the machine. From the CTC touchscreen-based HMI, semiconductor technicians can adjust process parameters and timing, access diagnostic information, monitor the machine's operation, or run the machine manually.

EF Precision Design and CTC provided a glimpse into the future of control technology at the Semicon West Show. At the show, EF Precision Design demonstrated CTC’s patented web server technology that allows the CTC controller to serve a web page to a remote PC running only Internet Explorer. This technology allows the remote browser based device to interactively view and modify the machine’s operation.

The ability to remotely access the machine over an Internet or intranet connection opens up many possibilities for improving machine servicing. At a time when many companies are downsizing, the people who are responsible for maintaining the system may have too many other responsibilities to spend time learning how the system works from the vendors during installation. "The customer may have trouble explaining even what the problem is, because they don't have the time to fully understand how the system works," said Rich Birett, Senior Electrical Engineer at EF Precision Design. Lacking the time to investigate why the system doesn't work as expected, stretched system administrators turn to vendors for technical support, and a service call results. Birett continued, "The problem may be fixed in five minutes, but it might take a day to fly out there first. We are promoting the Internet as a service, that if you can access the tool at the customer's site, change parameters and monitor the process as it's running, you can address the customer's issues much faster."

CTC is delighted to be part of EF Precision Design's current and future success.