Impact of broad ion beam center alignment and mask position on Si wafer cross-section milling rate

Abstract When processing an area over 500 µm in sample cross-section processing using an ion beam, Ar broad ion beam (Ar BIB) is used. Place a mask over the sample to be cross sectionized and irradiate Ar BIB on the specimen set higher than the mask. As the mask is cut, the cross section is processed in a form that follows the cross section. In the case of commercially available equipment based on Si wafer, the height on the specimen is set within 100 um above the mask, and the milling rate is defined as the result of processing for 1 h. It is generally known that during BIB processing, half of the beam is irradiated to the mask, and the remaining half is irradiated to the specimen for processing. However. in this study, it was found that the milling rate increased whenever the center of the beam was raised on the mask little by little (within a few ums to 100 um). From this study, the irradiation position of the BIB was raised on the mask surface at regular intervals for the experiment, and through this, the definition of the beam size of the DC plasma ion gun was used in the experiment, and the change in the milling rate of the Si wafer was studied.