  The central star-forming regions in three blue compact dwarf galaxies (He
2-10, NGC 5253, and II Zw 40) were observed in the 340 GHz (880 micron) band at
5 arcsec resolution with the Submillimetre Array (SMA). Continuum emission
associated with the central star-forming complex was detected in all these
galaxies. The SMA 880 micron flux is decomposed into free-free emission and
dust emission by using centimetre-wavelength data in the literature. We find
that free-free emission contributes half or more of the SMA 880 micron flux in
the central starbursts in those three galaxies. In spite of the dominance of
free-free emission at 880 micron, the radio-to-far infrared (FIR) ratios in the
central star-forming regions are not significantly higher than those of the
entire systems, showing the robustness of radio-FIR relation. Based on the
robustness of the radio-FIR relation, we argue that the free--free fraction in
the 880 micron emission is regulated by the dust temperature. We also analyze
the CO (J = 3--2) emission data. We find that CO is a good tracer of the total
gas mass in solar-metallicity object He 2-10. Low-metallicity objects, NGC 5253
and II Zw 40, have apparently high star formation efficiencies; however, this
may be an artifact of significant dissociation of CO in the low-metallicity
environments. We also point out a potential underestimate of dust mass, since
the dust traced by emission is biased to the most luminous high-temperature
regions, particularly when a system hosts a compact star-forming region where
the dust temperature is high.
