The Study Of DFM Method Of Copper Interconnection Technology

As the semiconductor fabrication ground rule has reached the 130nm node beyond,itseems that traditional SOC design technology cannot meet the need of advancedcopper metallization for Ultra-Large-Scale-lntegrated (ULSI) circuits needed to meetperformance requirements for advanced interconnect technologies.In this thesis,threekey copper interconnection process technology have been researched to developcopper interconnection DFM method.The main research subjects are as following:(1) Modeling of Optical Proximity Correction and process simulation.To study thedouble exposure mechanism,we have used a 248 nm deep-UV exposure tool andseveral well chosen photoresist to study and simulate the photo performanceparameters in the merge of two photo exposures.By photolithography simulation,wefind that traditional illumination conditions,together with PSM which has 6%refractive index,can be the best double exposure combination,process data also showthe same result.By process optimization,it seems that,with a traditional illuminationconditions (248nm 0.68NA/0.5sigma)combined with PSM which has 6% refractiveindex,photoresist B shows the most excellent performance,its process window canfit the need of double exposure,also by Optical Proximity Correction,the variation ofline-width at different pitch can be reduced to +/-5nm,At the same time,physicalSEM analysis also show the same result,so we can come to a decision that this designcan be used to manufacture.(2) Modeling ofW CMP erosion.Process experiments show that this model can beused to explain the abnormal phenomena of erosion after W CMP.And by this means,the monitor item for W CMP erosion can be skipped so as to lower down the cost ofowner.(3) Modeling of Cu CMP erosion.It is well known that topography resulting frompattern dependencies in various processes, especially Chemical-MechanicalPlanarization (CMP),is a major problem in interconnects.An pattern dependenterosion model for copper metallization is contributed to help understand and meeterosion requirements,to optimize the polishing process to achieve minimialenvironmental impact,higher yield and performance,and to enable optimization oflayout and dummy fill designs.