I will present ALMA high-resolution (~9 pc) continuum data of young massive clusters (YMCs) in the overlap region of the Antennae galaxy. The properties of these YMCs are key to understanding the star formation mechanism in starburst systems, especially mergers. We identified 6 sources in the overlap region, including one source which is actually composed of 2 YMCs. These YMCs corresponds well with radio sources in lower resolution continuum image in GMC scale (~40 pc). By comparing the free-free emission in 9 pc scale and 40 pc scale, we find more than 70% of free-free emission in GMC actually comes from these YMCs, which indicates a cluster bound fraction close to 100% in these extremely star forming clouds. We further calculate the virial mass of these YMCs using 12CO 2-1 cube and confirmed these YMCs are bound systems. We also calculated star formation efficiency of the host GMCs and find the value is between 1% ~ 5%, which suggests some GMCs should be at feedback stage. However, we didn’t see any increase in the GMC temperature, which probably indicates the feedback is only effective locally for these star clusters.