Deep-UV positive resist image by dry etching (DUV PRIME): a robust process for 0.3-μm contact holes

Classical positive resist process for DUV is not yet available and stabilized. We noticed various limiting points such as the delay time for resist material, the limitation of thickness related to ultimate resolution, and the bulk effect. P.R.I.M.E. (Positive Resist Image by dry Etching) process technology using DUV 248 nm exposure wavelength improve solutions for each process parameters, for example, a well known and stable resist (J.S.R- U.C.B PLASMASK 200G) is used with Hexamethyldisilazane (HMDS) as silylated compound. The combination of DUV exposure and top surface imaging P.R.I.M.E. process can open contact holes down to 0.3 micrometers with a large process window and a good wafer uniformity. This publication will show the improvement of each process parameter. Extended information will be given for process latitude (focus and exposure). We demonstrated and verified the feasibility of the contact holes process by etching 1 micrometers oxide (BPSG + USG) through the PRIME process lithography.