Self-heating effects (SHEs) were studied on the vertical nanoplate-shaped gate-all-around (GAA) FETs (vNPFETs) as a target of 5nm node technology. The thermal properties are compared between face-up and face-down configuration. Decreasing the channel width is vulnerable to both configurations in terms of SHEs due to the reduced area of heat dissipation. It is well known that the SHE is alleviated on AC condition, while our results show that the SHE is still important in vNPFET on AC condition.