Chemical Mechanical Polishing / Planarization: Slurry Measurements

Relevant for the semiconductor industry

Chemical mechanical planarization (CMP)

Chemical mechanical planarization (CMP) is a critical production step during microcircuit manufacturing. The smaller the electronic components the more sophisticated the CMP process. The customer goal is to have flat, smooth, polished wafers.


Figure: Sketch of a polishing machine

The polishing procedure is performed in clean rooms where the air contains less than one dust particle per cubic meter. Slurry containing mainly pure water, a chemical reagent and different polishing particles are used between the polishing pad and the wafer. A dynamic measurement of the slurry properties coupled with defined control limits can be used to determine a slurry “health”.

Inline monitor with L-Dens 7400

The inline monitor from Anton Paar, equipped with the density sensor L-Dens 7400, continuously monitors and displays the actual density and actual temperature of the slurry.


  • Provision of real-time data to indicate slurry health
  • Detection of changes in abrasive concentration
  • Identification of each slurry type with an ideals(target) density value in case different slurries are used





Specifications of L-Dens 7400 SST

Measuring range: max. 3 g/cm3
Process temperature: -40 °C to 125 °C
Ambient temp. range:
                          -40 to +70 °C (65 °C)
Process pressure: max. 50 bar (abs.)
Typical repeatability: 0.02 kg/m³



Do you have any questions? 

Contact Anton Paar directly: process[at]