Aluminum Metalization Defect Research In Integrate Circuit Technology

With the development of integrate circuit technology, the feature size becomes smaller, metal lines become narrower and metal layers increase. Aluminum metalization is facing more challenges. The key problem is how to reduce metal defect to improve the product yield. Three typical metal defects will be discussed in this paper: arcing defect during Aluminum deposition; ring type defect during metal etch; Aluminum protrusion defect during VIA barrier deposition.The root cause of arcing defect is the result of charge-breakdown on the target of sputter chamber. Delete"ignite"step and increase DC power ramp up rate in recipe will be useful to reduce such kind of defect. Avoid chamber leakage will be effective too.Ring type defect happens when big aluminum grains make metal barrier crack. TMAH get into metal barrier and corrode aluminum. This leads to etch incompletely and causes ring type residue. Increase Ti/TiN thickness or shorten deposition time is both useful to reduce such kind of defect.Aluminum protrusion defect has strong correlation with high pre-heat temperature before CVD TiN. It makes aluminum expanding and then fill in VIA holes. Increase IMP Ti thickness can avoid aluminum expanding into VIA and reduce this kind of defect. If new kind of heater, which has gas holes on heater surface, is used, better pre-heat condition will also be effective to prevent aluminum from protrusion.