Automated Wet Benches

Wet Benches are workhorses in the manufacture of semiconductors. Their primary role is to clean, etch, and prepare substrates, typically wafers, for the next step in the overall manufacture of integrated circuits. Wet benches are also commonly used to clean parts.

With regard to automation, wet benches are typically grouped into three major categories:

Manual Wet Benches
SemiAutomated Wet Benches
Fully Automated Wet Benches

Semi Automated Wet Benches – The wafers (or substrates) to be cleaned are moved from bath to bath by virtue of an automated robotic handler incorporated in the tool. Semi automated wet benches do not have integrated wafer dryers. Therefore the substrates must be hand carried by an operator to a different tool for drying. Semi Automated Wet Benches are dry-in wet-out tools.

Shown to the right are examples. We see a front to back semi automated wet bench and a separate set of spin rinser dryers.

The term 'Automated Wet Bench' refers to both scenarios explained above. Therefore, it’s reasonable to say that an automated wet bench is just about any wet bench that is not a purely “manual bench”.

By “manual wet bench” we mean that an operator has to move wafers from one bath to another, using a wafer cassette carrier with some version of safety handle. Such benches are widely used in wafer cleaning and etching, but mainly where less sophisticated technology is manufactured. Manual Wet Benches are also widely used as parts cleaners for quartzware, chamber parts, filters, traps, plumbing lines, chucks, and many other FAB related objects.

After the wafers are processed and rinsed, they are hand carried to a dryer. Shown to the right is a spin dryer that uses centrifugal force to dry the wafers.

Fully Automated Wet Benches – These tools have integrated wafer dryers. All wafer moves are done using automated robotic handlers. Aside from the initial loading and unloading of the wafer carriers, there are no moves requiring operator intervention. A Fully Automated Wet Bench is a dry-in dry-out wet processing system.

Shown here (left) is a parts cleaning wet bench that deploys a perforated shelf used as a support tray for submerging quartzware, filters, traps, plumbing, equipment, chamber parts, etc. These tool are most widely manual systems, but there are also many semi automated versions available.