I present dust features and masses observed in young supernova remnants (SNRs) with Spitzer Infrared Spectrograph (IRS) mapping and staring observations of a few youngest supernova remnants including Cas A, SNR 1E102.2-7219 (E0102), N132D, G11.2-0.3 and G54.1+0.3. The spectral mapping data revealed a number of dust features which include 21 micron-peak dust and featureless dust in Cas A and 18-micron peak dust in E0102 and N132D. We also report the 21-mcron dust feature from another SNR of G54. 1+0.3 and compare with those of Cas A. The 18 micron-peak feature is fitted by a mix of MgSiO3 and solid Si dust grains, while the 21-micron peak dust is by a mix of SiO2, silicates and FeO; we also explore dust fitting using Continuous Distribution of Ellipsoid grain models. We report detection of CO first overtone band from Cas A in near-infrared imaging and of CO fundamental band using AKARI spectra. We review dust features observed and identified in other SNRs. The dust emission is spatially correlated with the ejecta emission, showing dust is formed in SN ejecta. The spectra of E0102 show rich gas lines from ejecta including strong ejecta lines of Ne and O, including two [Ne III] lines and two [Ne V] lines which allow us to diagnostic density and temperature of the ejecta and measure the ejecta masses. I discuss compositions and masses of dust and association with those of ejecta and finally, dust contribution from SNe to early Universe.