# Cerium (CeO) behavior in Glass Polishing?

I am basically working in semiconductor industry and I specifically taking care of CMP (Chemical Mechanical Polishing). We did polish glass (borosilicate type of glass) and we are using slurry (which is cerium-based) as the chemical compound. Our polishing time was quite long (~40 min) and without chilling the slurry, it could deteriorate the polishing pad, material removal etc. I have decided to chill the slurry (CeO) at temp ~20 °C prior supply to my polishing machine.

How does this Ce chemically and mechanically impact my CMP performance? What is the agglomeration index of this Ce with the changes of temperature?

Any good article to share?

• CeO is not a thing at all. – Ivan Neretin Mar 5 '19 at 6:04
• @IvanNeretin I just thought I'd let you know that the OP may have gotten "CeO" from a seemingly authoritative source and repeated it in good faith. Instead of writing "I think you mean Cerium oxide or "CeO2 is what they polish their glass with", or even making a helpful edit to improve a new user's first question, you wrote something terse and discouraging. I'm all for helping people learn chemistry, but a ruler across the knuckles isn't (always) the best way. – uhoh Mar 5 '19 at 12:21
• @uhoh Discouraging, if you ask me, is to have the door slammed shut in your face. I mean all those close votes - where are they from? The question is totally legitimate, even if I have nothing to say on it other than pointing out one minor error (which is not even the OP's fault, nor did I say it is). – Ivan Neretin Mar 5 '19 at 12:33
• As a fun fact, ceria containing ores also commonly contain radium, so your polishing compound is likely radioactive and needs proper disposal. – Jon Custer Mar 5 '19 at 15:08
• Be careful with how the words end - cerium is a metal or a chemical element, whereas ceria is a cerium oxide. – voffch Mar 8 '19 at 9:04

My guess is that for the reason why your slurry deteriorates without chilling you should look the other way. Maybe the other slurry components are to blame? I do not see how ceria could impact the slurry performance in your case. Ceria (and yes, it's $$\ce{CeO2}$$ not $$\ce{CeO}$$) and some other oxides like zirconia are used in milling and polishing chiefly because of their physical hardness and chemical inertness. In other word, $$\ce{CeO2}$$ should probably be regarded as purely abrasive component. You need extreme conditions to chemically alter ceria, such as concentrated acids and a lot of prolonged heating, and the chemical interaction between ceria and the other solid materials is highly unlikely unless the temperatures are so high that the whole system starts to glow.