Specific Process Knowledge/Etch/AOE (Advanced Oxide Etch): Difference between revisions
| Line 18: | Line 18: | ||
There is a limit to how much the wafer can bow and still be clamped on the chuck. The limit can maybe vary a little over time and may also depend on the material on the backside of the substrate. On a 100mm Si wafer with SiO2 on the backside (<10µm) we expect the limit to be around 50µm bow (when the back side surface is convex). | There is a limit to how much the wafer can bow and still be clamped on the chuck. The limit can maybe vary a little over time and may also depend on the material on the backside of the substrate. On a 100mm Si wafer with SiO2 on the backside (<10µm) we expect the limit to be around 50µm bow (when the back side surface is convex). | ||
I have been able to etch much deeper in SiO2 with a P-Si mask than with a photo resist mask on a wafer with 50% load. When using photoresist the wafer stopped clamping during the etch after just a few µm. With P-Si | A bow will be created when etching the top oxide layer on a wafer with oxide on both sides. For a larger etch load the bow will be more severe for a specific etch depth when for a smaller etch load. I have been able to etch much deeper in SiO2 with a P-Si mask than with a photo resist mask on a wafer with 50% load. When using photoresist the wafer stopped clamping during the etch after just a few µm. With P-Si I could etch 15µm without problems. I expect this to be due to a combination of P-Si on the back side clamping much better and P-Si on the back side helping to reduce the bow. | ||
====Transparent wafers==== | ====Transparent wafers==== | ||