A method for manufacturing a semiconductor device is provided to prevent deterioration of characteristics and reduction of productivity by forming an alignment key with the same width on a lateral surface within an opening. An insulating layer(33) is formed on a scribe line of a substrate(31). An opening(35) is formed by patterning the insulating layer. A first metal layer is formed on the insulating layer in order to cover the substrate exposed by the opening. A spacer(38) having etch selectivity is formed on a lateral surface of the metal layer formed by the opening. The first metal layer is polished to expose the insulating layer by using the spacer as an etch-stop layer. An alignment key(39) is formed at the lateral surface of the insulating layer. A second metal layer is formed on the insulating layer in order to cover the alignment key.
