Abstract
Gold (Au) is a common metal that is evaporated using an electron beam evaporation within the compound semiconductor industry. It is common to place a crucible liner into a hearth to ensure the Au can be evaporated with a low and stable power density level. Au slugs are placed into a crucible to evaporate a desired amount of gold on to the semiconductor surface. Evaporating Au using e-beam evaporation presents several challenges that can typically be mitigated by modifying the parameters of the e-beam system. One intrinsic challenge with evaporating Au is that it wicks over the crucible liner causing buildup on the side walls of the crucible as well as build up in the hearth pocket. To combat the issue of buildup on the crucible, the buildup is ground down; grinding the crucible liners is not a long-term solution as it changes the characteristics of the liner as it thins down the side wall after each grind. Changing the crucible material can impact how much gold wicks out of the crucible, but it will not change the thin film of gold that forms on the pocket walls from the evaporation cloud. To overcome this issue, a consumable part can be placed into the hearth that may be removed after a certain number of deposition runs. Implementing a new crucible material in combination with the hearth inserts could resolve both issues and create a robust process for evaporating Au. Additionally, the reduction of Au buildup on the crucible liner and the hearth pocket will result in potential CapEx and OpEx savings in operations.
