Wafer thickness measurement tool

In Semicon especially in Singapore wafer fab which demand a high quality output, Every product will need to go tru some sampling check. Meaning to random check whether process is under control eg if we wants the metal deposition to be certain thickness, the machine cannot deposit more or less to certain percentage, eg plus minus 5%.

Thicker or thinner of the metal will affect the product performance.

So we use the RS machine to sampling check the thickness.

Measurement tool looks like this:

and the probe on the wafer in closer look.

So we look at the mean for average thickness in all areas of measurement, so some we take 49 points measurement, some 5 points, some 17 points

And the results also can be displayed in contour map. In this photo , thickness slanted one sided..

Also can choose 3D dimension map display to have better illusion how the thickness , whether slant one side , thick at center or whatsoever.