PCT Corrosion Failures

Guest

We loaded a lot in PCT. When we took out the lot, 60% failure rate. FA said the failures are due to corrosion. They said we should check our chamber. I wonder how he was able to tell it's our chamber that caused it. I think the lot is bad. What's the best way to settle the issue?

Rellab Guy

Posted: Fri Sep 19, 2026 12:11 pm Post subject:

Hi Rellab Guy,

It’s not easy being confronted by something like this, is it? First off, you need to ensure that your PCT system was not the one that caused this. Maybe this is the point being raised by FA. If you look at Jedec JESD22-A102, it says that the ionic contam of the test apparatus and chamber must be controlled to avoid artifacts. It also specifies a minimum resistivity for the water to be used.

You must show FA that you do not have any problems with the DI water you’re using for PCT before you go further with root cause analysis. Other signs that indicate you may indeed have a water problem: 1) other lots loaded with the lot also show metal corrosion or discoloration; 2) other PCT chambers are affected; 3) even the good units show metal discoloration; 4) the affected units do not show passivation defects; and 5) your D/I water has a Cl content of 0.2 ppm or higher.

Keep us posted!

EE