A method for manufacturing a semiconductor device includes: forming a first metal portion on a substrate, the first metal portion comprising a plurality of pores; preparing a structure body comprising a semiconductor stacked body, wherein a concave portion is provided in a first surface of the structure body; and bonding the first metal portion to the structure body, such that a first part of the first metal portion is bonded to the concave portion of the first surface, and a second part of the first metal portion is bonded to a part of the first surface other than a location where the concave portion is provided. In bonding the first metal portion to the structure body, the first metal portion is bonded to the first surface such that at least a portion of the concave portion is filled with the first metal portion.