Method for processing product layer

A method for processing a product layer, comprising:

• providing a dielectric layer over a substrate, wherein the substrate includes a plurality of fins on a base substrate, a hard mask layer is formed on the plurality of fins, an isolation layer is formed between the hard mask layer and the plurality of fins to improve bonding strength between the hard mask layer and the plurality of fins, and the dielectric layer has a top surface coplanar with a top surface of the hard mask layer;
• etching, by a drying etching process, to remove a portion of the dielectric layer and forming a product layer by depositing a product from the drying etching process over the etched dielectric layer, wherein a top surface of the product layer is lower than the top surface of the hard mask layer and higher than a top surface of the isolation layer;
• and
• removing the product layer by providing a dissolving solution and using the dissolving solution to rinse or soak the product layer to dissolve the product layer.