Electrical characterization of platinum deposited by focused ion beam

Focused ion beam (FIB) systems are commonly used to image, repair and modify integrated circuits by cutting holes in passivation to create vias or to selectively break metal tracks. The ion beam can also be used to deposit a metal, such as platinum, to create new connections. These techniques are very useful tools for debugging designs and testing possible changes to the circuit without the expense of new mask sets or silicon. This paper presents test structures which can be used to characterize a FIB induced platinum deposition process. Sheet resistance test structures have been fabricated using a FIB tool and the results of testing these structures are presented. The sheet resistance data has been used to fabricate platinum straps with a known resistance. This extends the capability of the focused ion beam system beyond the deposition of simple conducting straps. The design of the test structures has been improved through the use of current flow simulation to investigate the effects of geometry and misalignment on the measurement accuracy. The results of these simulations are also presented.