A method for manufacturing a semiconductor device includes: providing a wafer-bonding stack structure having a sidewall layer and an exposed first component layer; forming a photoresist layer on the first component layer; performing an edge trimming process to at least remove the sidewall layer; and removing the photoresist layer. In this way, contaminant particles generated from the blade during the edge trimming process may fall on the photoresist layer but not fall on the first component layer, so as to protect the first component layer from being contaminated.