Cleaner, Neater Tools Perform Better
By Joe Farah
"Spring has Sprung!" And that can only mean one thing: it’s time for spring cleaning. So it’s a perfect time to discuss the importance and benefits of overall production system cleanliness.
In the semiconductor world, when people think of tool cleaning they are usually referring to "chamber cleans," which are done frequently based on wafer count, RF hours, or some other measure of tool activity. Chamber cleans, or chamber PMs, are essential to ensure that process chambers are returned to a normal condition for continued wafer processing.
Since chamber PMs are driven by tool activity, we tend to ignore the benefits of overall system cleanliness. But performing comprehensive systems cleans should also be part of the process of tool maintenance because it plays a key role in extending system longevity and reducing downtime.
As we perform maintenance on a system, whether preventive or corrective, some items that should be part of a maintenance checklist are often missed, in part because they are in areas of low visibility. What I’m referring to here are overall checks of the system’s wiring, interlocks, major cables, boards and panels, to mention just a few of the critical items.
Tidy up the tools
Semiconductor tools go through many corrective and preventive maintenance routines. Some of them are planned; others are unscheduled downs or even PMs due to any number of incidental issues. Some require basic part removal and replacement and others, in the case of troubleshooting, require removal of critical cables and electronic boards. Here are a few items that may be missed during preventive or corrective maintenance, but which should be routinely checked.
- Small screws that hold control boards in place in the electronics cabinet
- These should be checked and tightened because boards with loose screws can vibrate and become unseated, which could result in a system crash
- Cables connected to interlocks, main flow controllers and communication boards (also referred to as D-connectors)
- These must be checked and tightened regularly to keep a good connection and to avoid miscommunication or erroneous temperature/pressure readings
- Major parts such as RF generators and DC power supplies
- Ensure that the water-cooling fittings are seated correctly, safety covers are installed, and communications and power cables are nice and snug
- Hose clamps and water fittings
- If not checked and seated or tightened correctly, these fittings can cause tremendous damage to a system
- Chambers, doors, and--specifically--gas panel doors and any gas or electrical cabinets must be carefully checked. This is critical for personnel and equipment safety.
- Panels, doors and floor covers
- Load-lock panels and door covers for 200mm systems should always be installed and snug
- Front interface doors should always be closed to prevent particles migrating in- and through the load-lock, and to prevent injury from the movement of the front robot
- Floor panels to cover critical wiring, valves and to prevent objects falling into the system’s mainframe
- Air-actuated valves
- These valves are actuated by air forcing the valve to open, so if the air hose is not pushed all the way into the air fitting, the valves may not open all the way which will cause flow issues.
- Heater jackets where installed
- Heater jackets, specifically for liquid flow lines, if not installed correctly after a PM or when replaced for failure, can cause cold spots which in turn may lead to particles in the chamber.
- Chillers and heat exchangers
- These are critical for process stability and for liquid level checks
- All-around cleanliness
- Tools, tie wraps, used O-rings, small parts laying around or in the mainframe, rags and other objects can be harmful if they contact electronic boards or sensors.
Overall, keeping the systems clean and clutter free, and ensuring no system-related objects are removed will go a long way toward keeping the systems performing to specifications.
At Applied Materials, we are committed to providing our customers with the best-performing systems and world-class service support. We recommend customers use our ON-Demand™ service for overall system checks and health assessments. Schedule yours today. Call the Applied Materials Global Customer Contact Center at 1-800-468-8888 (1-800-HOT-TTTT) and your local Field Service representative will contact you promptly. Or reach us by email at www.GCC_AMNA@amat.com, or online at www.appliedmaterials.com/customer-portal.
Joe Farah is Applied’ s Director of Service Product Lines for Dielectric Systems. You can reach him at email@example.com.