Disclosed is a vacuum chuck and a method for securing a warped semiconductor substrate during a semiconductor manufacturing process so as to improve its flatness during a semiconductor manufacturing process. For example, a semiconductor manufacturing system includes: a vacuum chuck configured to hold a substrate, wherein the vacuum chuck comprises, a plurality of vacuum grooves located on a top surface of the vacuum chuck, wherein the top surface is configured to face the substrate; and a plurality of flexible seal rings disposed on the vacuum chuck and extending outwardly from the top surface, wherein the plurality of flexible seal rings are configured to directly contact a bottom surface of the substrate and in adjacent to the plurality of vacuum grooves so as to form a vacuum seal between the substrate and the vacuum chuck, and wherein each of the plurality of flexible seal rings has a zigzag cross section.