CMP POLISHING PAD
A polishing pad has a polishing layer comprising a polymer matrix comprising the reaction product of an isocyanate terminated urethane prepolymer and a chlorine-free aromatic polyamine cure agent and chlorine-free microelements. The microelements can be expanded, hollow microelements. The microelements can have a specific gravity measured of 0.01 to 0.2. The microelements can have a volume averaged particle size of 1 to 120 or 15 to 30 micrometers. The polishing layer is chlorine free.
1 . A polishing pad useful in chemical mechanical polishing having a polishing layer comprising
a polymer matrix comprising the reaction product of an isocyanate terminated urethane prepolymer and a chlorine-free aromatic polyamine cure agent
and chlorine-free microelements having a specific gravity of 0.01 to 0.2 distributed within the polymer matrix.
2 . The polishing pad of claim 1 wherein the polishing layer has a chlorine content less than 0.1 wt % based on total weight of the polishing layer as determined by energy-dispersive X-ray spectroscopy.
3 . The polishing pad of claim 1 wherein the cure agent is an aromatic diamine.
4 . The polishing pad of claim 1 wherein the aromatic diamine has the formula
where either R 1 and R 3 or R 1 and R 4 are amine groups or alkyl amine groups having 1 to 5 carbon atoms and R 2 , R 5 , R 6 , and whichever of R 3 or R 4 does not contain an amine containing group are independently selected in each occurrence from H, -L-alkyl groups of 1-4, carbon atoms, where L is a direct bond, or a linking group selected from O or S.
5 . The polishing pad of claim 1 wherein the cure agent comprises diethyl toluene diamine (DETDA), dimethyl thio-toluene diamine (DMTDA), or a combination thereof.
6 . The polishing pad of claim 1 wherein the microelements have a shell comprising an acrylonitrile copolymer.
7 . The polishing pad of claim 1 wherein the polishing layer comprises the microelement in an amount of 5 to 50 percent by volume based on total volume of the polishing layer portion.
8 . The polishing pad of claim 1 wherein the microelement has a volume averaged particle size of 1 to 120 micrometers.
9 . The polishing pad of claim 1 wherein the microelement has a wall thickness of 30 to 300 nanometers.
10 . A polishing pad useful in chemical mechanical polishing having a polishing layer comprising a polymer matrix comprising the reaction product of an isocyanate terminated urethane prepolymer and a chlorine-free aromatic polyamine cure agent and chlorine-free microelements distributed within the polymer matrix wherein the polishing layer has a chlorine content less than 0.01 wt % based on total weight of the polishing layer as determined by Combustion Ion Chromatography (CIC) as set out in ASTM D7359-18, wherein the chlorine-free microelements having a volume averaged particle size of 15 to 30 micrometers and an average shell wall thickness of 30 to 300 nanometers.