Control of arcing problem in the passivation HDP deposition process solution

Arcing defect was found after passivation HDP film deposition. According to arcing defect cross-section analysis, passivation arcing occurrence shows a strong correlation with the metal exposed on the wafer. Metal exposed likes an electrode which will attract plasma to discharge on this position and caused arcing problem. Therefore, there are two approaches to suppress passivation arcing occurrence. One is to avoid metal exposed as an electrode and the other is to avoid unstable plasma discharged on wafer. New unbias liner oxide recipe was implemented to solve passivation arcing problem. It is proposed to increase the unbias liner oxide thickness under zero bias setting and to add additional buffer step for bias power ramp up step after the unbias liner oxide deposition. The thicker unbias liner oxide thickness can be isolated from exposed metal to contact with HDP high energy plasma directly, so the plasma will not be discharged on that position. And an additional buffer step for the bias power ramp up step can avoid the bias power overshot. This can prevent the unstable plasma being discharged on the wafer. According to our experiment and tracing results, the new unbias liner recipe is very effective to suppress passivation arcing occurrence and without other side effect.