Automatic generation of pressure compensation factors

It is well known in ion implantation onto photo resist (PR) coated wafers that there occurs a dose shift due to PR outgassing which encounters a charge exchange reaction to ion beams. It is proven that the Pressure Compensation (Pcomp) process can work well to avoid the dose shift even for multiple exchange processes. The Pcomp necessarily requires to determine two non-linear factors for each recipe. Once the correct factors are obtained, the Pcomp system works reliably for implantation even in a relatively high pressure with a beam of very high power. The process of determination of the factors, however, is very complicated and takes time. An automatic generation of the factors with software has been developed in order to reduce the number of these steps and time for users´ convenience and more productivity. This software collects data of the beam current and the system pressure in real time for a batch and calculates the optimized factors immediately after the batch, fitting the data using the least square method for non-linear equations. Users can check if the procedure is successfully done because the result is shown on the operator interface screen with graphically fitted data