Development of green CMP by slurry reduction through controlling platen coolant temperature

Abstract

Chemical mechanical polishing (CMP) is currently replacing a conventional chemical etching or mechanical polishing to remove overburdened copper deposit in printed circuit board (PCB) manufacturing process owing to its ability to realize a global planarization. In order to stabilize the CMP as one of the PCB manufacturing processes, the CMP machine has been investigated. This paper introduces a newly developed Oscar-type CMP machine and copper CMP process to polish rectangular PCB with a size up to 510 mm by 510 mm, especially focused on the effect of platen coolant temperature on removal rate and removal uniformity during copper CMP to reduce the amount of slurry consumed. The CMP experiments are implemented under the coolant temperatures of 10, 15, 20, 25 and 30°C, and the slurry flow of 600, 800, 1000 and 1200 mL/min. The experimental results show that the removal rate goes up with an increase in the platen coolant temperature during polishing at a fixed slurry flow rate, and the removal rate goes down at any fixed the platen coolant temperature when the slurry flow rate increases. It means that the reduction of thermochemical reaction rate in the chemical mechanical removal, resulting from cooling down of the copper surface when the.