  Local metal interconnection is widely used in modern complementary metal
oxide semiconductor (CMOS) technology. The most frequently used local materials
are some heavy metals, such as tungsten (W) or copper (Cu). It's well known
that single event upset (SEU) could occur in a CMOS under neutron exposure. In
this paper the rectangular parallelepiped (RPP) method is used to investigate
the SEU response of a typical CMOS. SEU induced by 1$\sim$14\:MeV neutrons are
simulated with Geant4 and the cross sections are calculated. The results show
that only in the structure with W, secondary particle $\alpha$ is created and
SEUs are generated when the energy of neutron is less than $4$\:MeV.
