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Rotary Wet Benches – This architecture deploys a central robotic handler that moves in a circle fashion from one process bath to another. I’ve never seen a Rotary Wet Bench with an integrated dryer. Most, if not all, Rotary benches are Semi Automated wet process tools.
Automated Wet Process Equipment can require wafer carriers, or they can be carrier-less. These carriers are often called cassettes or boats.
Cassette Style Automated Handler – Wafers must be transferred from the typical plastic FAB Carrier to a PTFE Process Carrier made specifically for the wet process tool. Both the wafers and the carrier are submerged into the chemical for cleaning, etching, rinsing, and drying.
Cassetteless Style Automated Handler – The wet process equipment removes the wafers from the plastic FAB Carrier and a very specialized robotic end-effecter transfers the lot of wafers from the wafer stage to each process bath. The process and rinse baths have fixtures inside them to support the wafers during processing. There are no Teflon (or quartz) Process Carriers needed in a cassetteless wet bench.
The benefits of cassetteless over cassette style are:
- No need for process carriers
- No need for wafer transfer tools, often done separately from the bench
- The bench does not have to clean a dry a process carrier
- The wafers are not contaminated by a process carrier
- The wafers are not shrouded by a process carrier
- Cleaning and drying times are shorter and more efficient
- Cassetteless benches have better throughput
- Cassetteless yields superior results on the wafers
Semi Automated Rotary Wet Bench
Linear In Line Automated Wet Bench - This architecture is common in most FABs and can be equipped with an integrated dryer. However, the example shown to the right does not have an integrated dryer. Therefore, it is a semi-automated linear bench.
Common SemiAutomated Wet Process Equipment
The linear wet bench architecture shown above has 4ea process baths (shaded blue) and two load ports (shaded white). A rear mount robotic handler slides on a rail to move the lot of wafers from one bath to another.
In Line Linear Style Example
Rotary Style Example
The Rotary Wet Bench architecture shown above has 4 process baths (or could be 3 process baths and dedicated loading area).
In Line Linear
Semi Automated Wet Bench
Cassette Style Robotic Transfer
Cassette-less Style Robotic Transfer
Cassette VS Cassetteless
Automated Wet Process Equipment
In Line Wet Benches - this architecture shows a rear mount robot full automated wet process system. On the right side are two load/unload ports. Just left of it is an integrated IPA Marangoni Dryer, followed by 6 process baths.
Marangoni Drying Loadloacked Chamber
Fully Automated In Line Linear Style Example
Automated Wet Process Equipment
Semi Automated Wet Process Equipment comes in a variety of architectural make ups. Most common are the Rotary versions and the In Line Versions.
It is a generally accepted fact that cassetteless is superior to cassette style wet processing with regards to both throughput and process quality. Sophisticated FABs simply must use cassetteless wet cleaning technology to get the results on the wafer that they need. The world’s marketshare leaders in wet process equipment manufacture cassetteless wet benches almost exclusively.