An optoelectronic device includes a semiconductor structure having a first side and a second side opposite to the first side, a first pad at the first side, a first finger connected to the electrode pad and having a first width, an insulating layer at the second side and comprising a first part under the first finger, the first part having a bottom surface with a second width larger than the first width and a side surface inclined to the bottom surface, and a contact layer covering the bottom surface and the side surface.