Provided a manufacturing method of a semiconductor light emitting device including forming a plurality of light emitting cells that are separated on a first substrate, forming a first planarization layer by providing an insulating material on the plurality of light emitting cells, forming a second planarization layer by providing a photoresist on the first planarization layer to have a flat upper surface, and soft baking the photoresist, and dry etching the second planarization layer to a predetermined depth to expose a portion of the first planarization layer provided on the plurality of light emitting cells, and a portion of the second planarization layer remaining between the plurality of light emitting cells on the first planarization layer, wherein forming the second planarization layer and dry etching are repeated at least once to remove the portion of the second planarization layer provided between the plurality of light emitting cells.