We investigated the thickness distribution of gold particles sputtered by a focused ion beam (FIB) and deposited on a section perpendicular to the irradiated surface. The calculation results were analyzed from the viewpoint of three-dimensional metal-assisted secondary ion mass spectrometry (3D MetA-SIMS), a novel method that uses sputtered metal particles to enhance the signal yield of organic samples. The calculated distributions showed characteristic shapes of deposited gold, which had both a steep area and a flat area. The former area can be used for determination of sputtering feature, and the latter area can be used as the target area in which the sample section is located. The amount of particles on the target area was calculated to be within a reasonable range, implying that 3D MetA-SIMS can be realized with this simple and reasonable process. In summary, we established the foundation for enhancing the scope and effectiveness of 3D MetA-SIMS.