Scanning Tunneling Microscope (STM) was used to examine the morphologies of selfassembled InGaAs quantum dots (QDs). In order to induce the self-assembly, unlike the conventional Stranski-Krastanov (S-K) growth method, spatial thermal modulations in nanoscale were created in-situ on strained-but-flat InGaAs surfaces in a Molecular Beam Epitaxy (MBE) growth reactor by applying interferential irradiations of laser pulses (IILP). As-irradiated surfaces were examined using an attached ultra-high vacuum (UHV) STM. STM images indicate that the irradiation of 7 nano second laser pulse induces self-assembly of QDs. The average size of laser-induced QDs is smaller while their density is larger than that of QDs formed by annealing strained but flat epilayers conventionally. Furthermore, the dot density is modulated sinusoidally with a periodicity commensurate with that of the interference, which suggests that the placement of QDs can be controlled on the scale of the optical wavelength used. QD volume analysis suggests that dots grow faster laterally than vertically so that dots become flattened as they get larger.