The formation of dust in core-collapse supernovae (SNe) is one of the key processes 
in the chemical and physical evolution of supernova, with implications for the origin of
dust in the interstellar media of galaxies.

I will present Herschel Space Observatory’s discovery of a large dust reservoir in SN 1987A.
The estimated dust mass was 0.4-0.7 solar masses, which is more than 1000 times larger than
the previously reported mass. Following ALMA high-angular resolution images have confirmed
that cold dust grains were formed in the supernova ejecta. A significant fraction of the elements 
synthesized by the supernova have now condensed into solid phase (dust grains), 
showing supernovae as dust factories.
ALMA also discovered unexpectedly strong CO and SiO rotational lines in SN 1987A, 
showing supernova ejecta are filled with cold molecular gas. Recently arrived cycle-2 
ALMA data suggests more molecular species are present. ALMA will provide crucial constraints 
on supernova chemistry, with an implication of more precise modelling of chemical evolution of galaxies.