Silicon wafers and a process for their manufacture wherein both slip dislocation and occurrence of warpage are suppressed include heat treatment to provide wafers having plate-shaped BMDs, a density of BMDs whose diagonal lengths are in a range of 10 nm to 120 nm, of BMDs present in the bulk of the wafer at a distance of 50 μm or more is 1×1011/cm3 or more, and the density of BMDs whose diagonal lengths are 750 nm or more in the wafer bulk is 1×107/cm3 or less, and the interstitial oxygen concentration is 5×1017 atoms/cm3 or less. The process involves low and high temperature heat treating at under defined temperature ramping rates.