HF Fumer Drawer Bench

HF Fumer Drawer Bench with interchangeable drawers to accept differing wafer sizes

Plade designed and developed this system to carry out 200 angstrom etches on the rear surface of wafers using HF acid fume. The design brief requirement was to etch to a closer tolerance than was being achieved with existing equipment. The existing equipment provided very poor control over the process and to ensure a minimum 200 angstrom etch on every wafer some wafers would be subjected to a 1200 angstrom etch (500% overreach).
HF Acid Fumming Etch Wetbench Photo

Developed for the UK satellite factory in Scotland of a major US semiconductor manufacturer the machine was so successful that a second machine was ordered within months and installed by our engineers in the US Company's factory in Malaysia.

The final design was conceived around a dedicated wet process station, which comprised of one 4-drawer box unit arranged to provide 4 totally separate etching chambers. Each chamber was provided with its own HF fume distribution system, its nitrogen purging system and dedicated controls. Special sliding drawers were provided with machined locations for the wafers and for test pieces. Drawers for 4 inch, 5 inch, 6 inch and 8 inch are available giving spaces for 28, 18, 12 and 8 wafers respectively. Drawers are easily changed and any combination can be used without reducing the quality of the etch.

Animated HF Acid Etch Wetbench
A high level of control through the Plade Six Sigma Gateway, PC based control system is provided, with comprehensive safety interlocks controlling access to the fume drawers, fume flow rates, extraction volumes, purging levels, pressure relief levels and other functions. An HF gas detection and warning system is also provided to ensure maximum safety for the operator.