Patent ID: 11495471

Abstract:
A semiconductor substrate has an exposed surface having a compositionally uniform metal, and an embedded surface having the metal and an oxide. The exposed surface is polished using a first slurry including a first abrasive and a first amine-based alkaline until the embedded surface is exposed. The embedded surface is polished using a second slurry including a second abrasive and a second amine-based alkaline. The second abrasive is different from the first abrasive. The second amine-based alkaline is different from the first amine-based alkaline. The metal and the oxide each has a first and a second removal rate in the first slurry, respectively, and a third and fourth removal rate in the second slurry, respectively. A ratio of the first removal rate to the second removal rate is greater than 30:1, and a ratio of the third removal rate to the fourth removal rate is about 1:0.5 to about 1:2.