Applications Of Contamination Analysis Of SIMS In Semiconductor Failure Analysis

Integrated circuit (IC) is the circuit which integrates all kinds of circuit devicesonto the surface of semiconductor. IC has became the heart of the modern electronicproduction due to its character of “light, thin, short, small”. The impuritycontamination has became the main root cause of unnatural failure of IC productionbecause the modern IC process has became more and more refined. Some kinds ofimpurity contamination, such as surface contamination on thin film, interfacecontamination and contamination in doping, can not be detected and measured by theroutine optical and electron microscope. Micro-elementary analysis must beperformed to realize their composition, concentration and distribution. And SecondaryIon Mass Spectroscopy (SIMS) is the leading technology of this application.Secondary Ion Mass Spectroscopy uses the ion beam to impact the sample andexcitated secondary ions, which will be collected and counted to calculate theelementary distribution and dosage in solid sample. This project uses CAMECAIMS-6f and ATOMIKA4500SIMS to research the main parameters, such as speciesof primary ion source, energy and beam current of primary ion beam, the angle ofincidence, species of secondary ions, mass resolution capability of mass analyzer etc.,impact the detection limit, landscape orientation resolution capability, sputter rate..Considering the character of impurity contamination analysis, the analysis conditionwill be optimized. The experiment result shows that appropriate species of primaryion source, bigger energy and beam current of primary beam can increase the sputterrate and decrease the detection limit. Smaller beam current can decrease the diameterof primary beam which can decrease the sputter rate but increase landscapeorientation resolution capability and didn’t acutely impact the detection limit. Toincrease the angle of incidence to a suitable level can increase the sputter rate acutely.To choose suitable species of secondary ions can decrease the detection limit. Toincrease the species of secondary ions excessive will decrease the signal of secondaryions and decrease the detection limit.At last, combining three examples, analysis of Molybdenum contamination withBF2ion implant, Boron and Phosphorus contamination diffusing from dopinginsulative oxide layer to active area of device, Arsenic auto-doping effect in siliconwafer, the application in semiconductor production failure analysis of SIMS impuritycontamination analysis was researched. It shows that SIMS can be used to analyze notonly the impurity element taken with ion implant, but also the doping element withabnormal distribution which is caused by thermal process. And SIMS also have awide application of establishing the failure model, judging the failure mechanism,protecting failure resend in semiconductor field.