Study Of The Effects Of Corrosion Inhibitors On Copper Trib-Electrochemical Performance

In order to reduce the electromigration and improve the interconnect performa- nce in multilayer routing, global planarization become an essential process in the next generation of IC chip manufacturing. Because of over-polishing and large- downforce, Chemical Mechanical Planarization (CMP) technology may cause damage to Cu/low k layer such as interfacial debonding and surface damage.The emerging Electrochemical Mechanical Planarization (ECMP) technology which removes material depending on mechanical and electrochemical synergies, can meet the need of planarization for next generation integrated circuits(IC). It can remove material under very low downforce, with no damage to insulating barrier. The theme of this article is to study the effects of corrosion inhibitors on copper trib- electrochemical performance on an experiment system developed to simulate ECMP process, and the processing parameters are optimized for Cu-ECMP.The simulative experiment system developed according to the principle of ECMP proves to be able to meet the ECMP experimental requirements. Both the electrochemical and friction signals can be gained online by the system, along with the advantages that speed and downforce can be adjusted.In the HEDP system containing of different inhibitors such as BTA, PTA, and 5Me-BTA,Cu-ECMP was simulated on the friction and wear tester. In the condition of static corrosion ,electrolyte and voltage for Cu-ECMP are optimized firstly based on anodic current and Inhibition Efficiency(IE).In this step, Linear Sweep Voltam- metry(LSV) and Chronoamperometry used for electrochemistry are applied. Voltage, speeding and downforce are studied in Cu-ECMP experiments secondly. With the influence to current, friction coefficient and surface morphology, technics for Cu- ECMP in different corrosion inhibitor system are optimized.The microscopic surface morphology, roughness and contour for Cu after ECMP in different inhibitors suggest that 5Me-BTA is better than BTA or PTA. Based on the results of Cu-ECMP experiments, the technological parameter of 0.5V in 30%HEDP+0.003M 5Me-BTA is optimized: speeding 0.0125m/s, with downforce 50g.Doing Cu-ECMP experiment for 10mins in the way of forementioned condition, the roughness can be reduced to 9.0nm,with the Material Removal Rate (MRR) at 0.275mg/min.The results analyzed by X-ray Photoelectron Spectroscopy(XPS) confirm Cu-BTA film on the copper surface ,which is resultant of reaction from BTA and Cu+. Considering of molecular structure of inhibitors,the mechanism of Cu-BTA film generation is expounded from the perspective of molecular adsorption.