Irradiation Uniformity Measurement at the New Beam Line of 1.7-MV Tandem Accelerator

A new beam line was designed and installed at the 1.7 MV pelletron-type tandem accelerator (NEC 5SDH-2) of KOMAC (Korea Multi-purpose Accelerator Complex). This beam line can be utilized for power semiconductor fabrication, nuclear material radiation hardness test, ion beam analysis, neutron production, etc. Especially, for the power semiconductor applications, a large-area irradiation, more than 5 inch in diameter, is required. Reflecting these users' requirements, we developed a new beam line by which we can irradiate 6-inch wafer. At the target chamber, we installed sample holder for 6-inch wafer positioning and Faraday cups for in-situ dose and uniformity monitoring. The uniform irradiation is performed by using electrostatic ion beam raster scan system of NEC. The results of uniformity measurements using Gafchromic film, Chromox plates, and Faraday cup are presented. A new beam line was installed at the 1.7 MV tandem accelerator. The maximum irradiation area is larger than 20 cm x 20 cm and the uniformity is within ± 5 %. So, it is identified that this new irradiation beam line can meet users' requirement in the power semiconductor fabrication and activate the utilization of the 1.7 MV tandem accelerator.