The Research Of Impacting Factors And Improvement For Within-shot IDSAT Uniformity

With the continuous development of the integrate circuit technology, thecontinuous reduction of the size of the device, the error on device by manufacturingprocess itself has been a key impact factor to device. Due to these errors, the designwas supposed to be exactly the same device will see a big difference in the actual test.And the Idsat is the key parameter to device performance, so the Idsat uniformity hasbecame one of the important target to the quality of product.In this thesis, firstly, introducing the structural features of the sub-micron MOSdevices, such as channel doping engineering, gate engineering, S/D engineering,interface engineering and technology variation. Based on these, researching the maincauses of the impacting factors for within-shot Idsat uniformity (IDU) improvementwere analyzed, and a model to characterize the impact factors was presented. RTAprocess is one of main factors leading to high IDSAT non-uniformity within-shotbecause its initial temperature, ramp-up rate, gas flow rate and ramp-down rate canaffect the amount of thermal absorption and thermal distribution in the chip. Thereforethe optimized RTA process can improve the thermal distribution in the chip, hence theIDU across the wafer.Then researching the correlation of the transmission rate，pattern density and theequivalent reflectivity to the device performance. The use of this model can help toprovide the guideline for the optimized arrangement of multiple chips within the shotto achieve better IDU performance. Based on the model simulation results, we canmodify the chip arrangement within the Multi-Project Wafer (MPW) shot in the waythat can optimize the RTA process and improve both NFET and PFET the Idsatuniformity. And all of these results must be confirm the yield data is OK.