Semiconductor structure and manufacturing method thereof

A manufacturing method of a semiconductor structure, comprising:

• providing a substrate, wherein the substrate comprises a first N region of a first N-type device, a first P region of a first P-type device, a second N region of a second N-type device and a second P region of a second P-type device, wherein the first P region is adjacent to the first N region and the second N region, and the second N region is adjacent to the first P region and the second P region;
• forming a gate dielectric layer, a first barrier layer on the gate dielectric layer, a first work function layer on the first barrier layer and a second barrier layer on the first work function layer on the substrate in sequence;
• forming a mask layer on the second barrier layer of the first P region and the second P region;
• removing the second barrier layer of the first N region and the second N region by a first etching process with the mask layer as a mask, so as to expose the first work function layer of the first N region and the second N region;
• and
• removing the first work function layer and the first barrier layer of the first N region and the second N region by a second etching process, so as to expose the gate dielectric layer of the first N region and the second N region.