“…11 We consider a surface reaction layer in a slurry holds the key to improve the conventional slurries or develop a new slurry for the requirements. There have been many reports concerning the reactivity of H 2 O 2 and Cu, [13][14][15][16] Cu etching properties, [17][18][19][20][21][22][23][24][25][26] properties of a surface reaction layer on Cu films in a slurry, [27][28][29][30][31][32] planarization mechanism, [33][34][35][36][37][38][39] and the relation between dishing and polishing pressure. 40,41 As for APS slurry, to the best of our knowledge, there have been no investigations into the chemical and mechanical properties of the reaction layer, formation mechanism of the reaction layer, or the effect of the reaction layer on the planarity, while there have been reports on the density, and thickness of the reaction layer as well as rotational torque during the CMP.…”