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Wet benches typically are fully automatic process platforms used to carry out wet cleaning and etching operations in semiconductor processing. They commonly consist of several tanks (or modules or “baths”), each containing either a cleaning or etching solution (for acid or solvent processing) or deionized rinsing water (DI) in which silicon wafers are immersed in a predetermined sequence that usually includes a drying process.

They come in a variety of configurations. An automated wet bench usually includes a load/unload station in which silicon substrates are fully processed and dried by the end of the sequence. A semi-automated wet bench features either linear or rotational transfer from module to module or multiple tanks for the sequence. A manual wet bench requires an operator to manually move a cassette from tank to tank. And an intelligent process station offers all the attributes of an automated system along with process control monitoring of the wet chemistries.

Typical applications for wet benches include:

• Cleaning and surface preparation to specified standards (e.g., RCA Clean and Standard Clean)
• Etching of films (such as Si, SiO2, and Si3N4) and alkaline etching of crystalline
• Stripping (photoresist and residue removal)
• Texturing of solar cells and MEMS devices
• Plating for electroless and electrolytic applications.

Common options for a wet bench include:

• Recirculating baths/filtration
• Megasonic and ultrasonic baths
• Bath spiking: Hydrogen peroxide DI water
• Bulk distribution: dispense chemicals to the station and individual baths
• In-situ particle monitoring
• Process control monitoring.

Here at Miller Plastics, we are sometimes called upon to work with customers in the silicon chip industry to design custom solutions to their wet-bench equipment needs. Typically, customers start by asking for a component that they want rebuilt, which can involve replacing complex piping systems, installing new sprayers in sink faucets, and swapping in new heaters, all with full fume evacuation, sliding front doors, windows, and cabinetry for storage of chemicals, among other things.

We are always ready to work with new customers on designing and building wet-bench components and systems. Please contact us for more information on how we can help you with your custom orders.