WCM   Wafer Charging Monitors, Inc.

Frequently Asked Questions
(Advanced FAQ's)

Wafer Charging in Ion Implantation

1.Q. What kinds of ion implants are most likely to cause wafer charging problems?
A. High-current implants used to fabricate source/drain junctions as well as some medium-current implants.

2.Q. Do flood guns or E-showers eliminate wafer charging during ion implantation?
A. They can significantly reduce wafer charging, but it can still be a problem, depending on equipment set-up.

3.Q. What is a "safe" beam current for a source/drain ion implant?
A. Contemporary ion implanters, when properly optimized, can be operated at the rated output of the implanter.

4.Q. Can I operate a high-current ion implanter at its rated output to maximize through-put and not cause charging damage to product wafers?
A. Yes. But it may require optimization of the implant parameters and charge control system settings.

5.Q. Can I use CHARM®-2 wafers to optimize the implant and charge control system settings to maximize through-put?
A. Yes, this is a straightforward application. Please contact WCM for more information.

6.Q. Does the polarity of the resist mask have an influence on wafer charging during ion implantation?
A. Yes, and the difference is significant -- as discussed in the following paper:

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