| 摘要 |
PURPOSE:To polish an Si wafer to 0.2nm of Ra (average roughness in a length of 0.1mm) by specifying an irregularity of a polishing cloth and using the cloth having 5-35 of formation index. CONSTITUTION:When a load is applied with fine powder of silica having a mean particle size of 0.02mum with KOH solution 3 of pH 9 by a surface pressure of 190kg/cm<2>, a relative speed of 10m/min of average is applied between a surface plate 1 and an Si wafer 4 to polish it by 5 of formation index alpha of a polishing cloth 2, 0.02nm of Ra is obtained. In another embodiment, when a load is applied with fine powder of silica having a mean particle size of 0.02mum with KOH solution 3 of pH 9 by a surface pressure of 350g/cm<2>, a relative speed of 3m/min of average is applied between the plate 1 and the wafer 4 to polish it by 35 of formation index alpha of the cloth 2, 0.2nm of Ra is obtained. Thus, the roughness of the wafer can be set to 0.2nm or less. |
