At semiconductor research centers and foundries, solvent wet bench stations provide a critical role in the semiconductor fabrication process. These stations are designed for operations that include substrate cleaning, photoresist stripping and liftoff pattern transfers. Since the solvents are often highly inflammable, wet bench equipment needs to be designed with stringent compliance to safety codes.
Equipping for safety
Precautions related to fire safety and electrical safety is among the most basic requirements in wet bench station design. Fire suppression can involve the application of spark-resistant electrical design all around, and the provision of extinguisher equipment. Solvent wet bench stations must be designed to meet Class 1 Div 2 certifications, and incorporate a carbon dioxide (CO2) fire system.
Safety alarms: Exhaust, CTA and N2 safety interlocks should monitor for use within acceptable ranges. Safety doors on the head case and elsewhere should be monitored during use and should be able to shut down operation if they are opened during use. Float switches should detect liquid spills on the floor of the bench. Differences in pressure between the exhaust on the bench and the rest of the room should be monitored through the use of photohelic gauges (low readings indicating incorrect operation should sound an alarm).
Carboy collection: Since solvent waste should never be sent down the drain, carboys help collect waste for containment. Multiple containment volume sizes are available. All come with current safety interface.
Heated solvent baths: Temperature control is achieved in many ways, and heated baths are one of them. They should be used to control the temperature of the solvents being used. Temperature controllers should be used both to raise and lower temperatures and to monitor temperatures.
Process timers: These vital pieces of equipment should be mounted to the head case to ensure that personnel are able to keep track of how long each process is to run.
Restrictions on use: A login system should ensure that only authorized individuals are able to access the bench.
In many cases, safety comes from simpler approaches — the use of auto lids made of Teflon or stainless steel to help seal off chemical containers.
Modutek’s Solvent Wet Bench Equipment
Available in manual, dry-to-dry, semi-and fully-automated designs, Modutek’s stainless steel solvent stations are constructed all through using 304 stainless steel. Solvent applications require the use of this material. From photoresist to IPA, and acetone, these stations are suitable for critical operations in the wafer processing activities. From solid works simulation to professional flow simulation, many critical flow characteristics are available. Improvements to productivity are achieved through the use of Modutek’s advanced software.
Modutek’s safety design for solvent processing involves every required feature. With wiring specified to NFPA 70 & 79 codes, emergency power off design for every safety interlock, lip exhausts on all solvent tanks, N2 head case purge design, photohelic EPO interlocks, safety shields, Teflon N2 guns, and continuous flow of the water manifolds, Modutek’s designs are among the safest of all wet stations.
With a chemical management interface, a PCL with touchscreen GUI, a rear access design, Teflon plumbing throughout, certification to the CE Mark, and seismic certification, Modutek’s equipment incorporates features beyond legally required safety measures.
Modutek’s Wet Bench Design and Build Process
Wet bench construction is a complicated process, and Modutek provides systems that are designed to meet the requirements of specific applications of individual customers. With 35 years in the business, Modutek understands that acid and solvent processing for micro fabrication requires customized solutions. Modutek’s designs and builds all their wet bench stations in house to ensure every part of the system provides reliable performance. If you need a solvent wet bench station designed and built to meet your requirement s contact Modutek for a free consultation or quote.
