Technical Difficulties and Optimization Methods of Nmos Share CT IN Contact Hole Etching

As the last generation of single graphics technology representative, 22nm is favored by advanced semiconductor manufacturers because of its higher cost performance. However, its key size is reduced to the process limit, the process window is very small, which limits the mass production of many semiconductor manufacturers. The most likely and most difficult problem to solve NMOS share CT open in contact hole etching(CT-ET). In this paper, based on local CDU, the removal of by-products in etching and regulating pattern loading of large holes and small holes, continuous process improvement is carried out, and effective solutions are proposed. Finally, the CDU was reduced by 36%, the contact resistance of CT was reduced by 30%, the NMOS Share CT size was increased by 100Å while the square CT size remained the same, and the NMOS share CT open was basically eliminated, which greatly improved the product yield and meet the requirements of process integration and mass production.