A system of cleaning a CMP pad used for removing copper from a substrate, the
system
comprising an abrasive cleaning pad, a cleaning solution delivery system that delivers
a cleaning solution, an analyzing system that monitors the characteristics of the
cleaning solution optically and chemically, and a carriage that allows the analyzing
system to monitor the cleaning solution at a plurality of locations on the CMP
pad. The use of the abrasive cleaning pad and the cleaning solution removes contaminants
from the CMP pad, and the contaminants are dissolved in the cleaning solution.
By measuring the concentration of contaminants in the cleaning solution, the condition
of the CMP pad can be monitored. To measure the concentration of the contaminants,
changes in the refractive index and absorption of light in the cleaning solution
are measured, wherein the refractive index and absorption depend on the concentration
of the contaminants. The concentration of the contaminants in the cleaning solution
is also measured chemically. Knowing the actual condition of the CMP pad during
the cleaning process allows for improved condition of the CMP pad.
