Semiconductor device, method of manufacturing the same, and led display device

A method of manufacturing a semiconductor device, the method comprising:

• forming, on a formation substrate, a sacrificial layer having a projection in a surface of the sacrificial layer opposite a surface of the sacrificial layer in contact with the formation substrate;
• forming, on the sacrificial layer, a planarized layer having insulating properties, the planarized layer having a first surface and a second surface opposite the first surface;
• forming, on the first surface of the planarized layer, a plurality of semiconductor elements;
• and
• forming a groove in the second surface of the planarized layer by removing the sacrificial layer,
• wherein the projection is located in a region outside the plurality of semiconductor elements as viewed in a direction perpendicular to the first surface.