are you looking for a Paste mask over vias?
Is that any doc that has suggested that?
if you look at TI manufacturer QFN layout guidelines
you will see they suggest solid vias
and stencil without a keep-out Paste zone
NXP suggests eventually to tent vias, but this is controversy among manufacturers
www.nxp.com/assets/documents/data/en/application-notes/AN1902.pdf
