A method for forming a semiconductor structure are provided. The method includes forming a dielectric layer on a substrate; forming a contact in the dielectric layer; recessing the dielectric layer so that the upper portion of the contact protrudes from the upper surface of the dielectric layer; and etching the upper portion of the contact to reduce the size of the upper portion of the contact. The semiconductor structure includes a substrate, a contact on the substrate and having an upper portion and a lower portion, a liner on the sidewall and bottom of the lower portion of the contact, and a dielectric layer surrounding the contact. The dielectric layer is in direct contact with the sidewall of the upper portion of the contact.