2pcs EP2SGX60EF1152C4 were found J05 open to GND issue at flex

Hi Wanni,

Please see my answers below, thanks.

1．What is the failure symptom? Please elaborate the failure symptom in detail.

Two pieces of EP2SGX60EF1152C4 were on two BIB boards tested function , failed “eeprom” , sent two BIB boards to ICT test , found 2pcs BGA point J05 open to GND .

2. When did the failure happen? How did you discover the failure?

Failure happened in the middle of April , found BGA point J05 open to GND in the middle of June.

Firstly tested function , failed “eeprom” .

Secondly sent two BIB boards to ICT test , found 2pcs BGA point J05 open to GND

Thirdly removed the 2pcs BGA from the BIB boards , measure 2pcs BIB boards with a multimeter , didn’t find trace or via hole open . Then added new BGA on BIB boards tested pass.

Last , measure 2pcs BGA with a multimeter , found point J05 open to GND , normal known good should be 300+ Ohm.

3. How did you determine the failure? Please elaborate the procedures.

First tested function , failed “eeprom” .

Second sent two BIB boards to ICT test , found 2pcs BGA point J05 open to GND .

Third removed the 2pcs BGA from the BIB boards , measure 2pcs BIB boards with a multimeter , didn’t find trace or via hole open . Then added new BGA on BIB boards tested pass.

Last , measure 2pcs BGA with a multimeter , found point J05 open to GND , normal known good should be 300+ Ohm.

4. Does the failure unit ever working before failure?

No , function test failed when the first time.

5. Did they violate solder re-flow temperature profiles, moisture sensitivity? Please provide the re-flow temperature profiles.

I'm collecting this information from our PE, will provide to you later.

6. Did you swap the failure device to a known good board? Is the failure following the device or board?

We didn’t do swap . We have measured the BGA , the failure following the BGA .