The chip is suspected to be electrostatically broken. There is only 1 PCS. After opening the cover, there is no obvious defect. How can I prove that it is electrostatically broken?

zhangpeggy

The chip is suspected to be electrostatically broken. There is only 1 PCS. After opening the cover, there is no obvious defect. How can I prove that it is electrostatically broken? [Copy link]

 

At present, about 50,000 chips have been used, and the EN pin of one chip is constantly turned off. After comprehensive analysis of various possible reasons, it is suspected that the chip is electrostatically broken. There is only 1PCS, and the cover analysis shows no obvious defects. How can we prove that it is electrostatic breakdown?

chunyang

It is impossible to prove it, but we can only analyze the probability of this possibility. Observe the routing of the EN pin loop on the PCB. If there is a long line and strong electromagnetic interference in the working environment, especially if the EN loop is directly exposed to the outside world, then the probability is higher.

常见泽1

If there is no problem opening the cover, do you need to do an emmi to see the current point?

wsmysyn

Have you done IV, backside, obirch, thermal, and delayer? If you can't find it, it's probably not ESD...

led2015

Try using an electrostatic discharge tester to test the chip, simulating the effect of electrostatic discharge on the chip, and observe whether the chip fails.

吾妻思萌

EMI damage can only be checked by PFA grinding, which is not easy to do. Why don't you try adding a few hundred CT scans to see if the damage becomes more obvious?

吾妻思萌

Electrostatic damage itself is a matter of dppm~

zhangpeggy

Azuma Simeng posted on 2023-3-30 07:12 Static electricity damage itself is a matter of dppm~

Is it the defective rate of the chip itself, or the defective rate of production?

qwqwqw2088

It is difficult for users to detect whether the chip is electrostatically broken.

Chip manufacturers have a way, they have special instruments to measure and judge

吾妻思萌

It is difficult for users to detect whether the chip is electrostatically broken. Chip manufacturers have ways to do this. They have special instruments to test and judge.

Manufacturing, packaging and transportation, work at the client and subsequent testing are all ESD risks.

吾妻思萌

It is difficult for users to detect whether the chip is electrostatically broken. Chip manufacturers have ways to do this. They have special instruments to test and judge.

The user's material is abnormal, and many manufacturers also test it out as defective.

qwqwqw2088

Azuma Simeng posted on 2023-3-30 15:18 The user's material is not normal, and many manufacturers have also tested defective

The electrostatic breakdown of the chip mentioned here requires chip manufacturers to perform ESD, or Electrostatic Discharge, testing on the chip.

qwqwqw2088

This includes simulating the electrostatic discharge process between the human body and the chip to test the chip's tolerance.

There are also electrostatic discharges that occur in simulated machines.

qwqwqw2088

There is also a test to simulate the static interference of the chip in the working state.

These require special instruments and then analysis.

吾妻思萌

This includes simulating the electrostatic discharge process between the human body and the chip to test the chip's tolerance. There is also a simulation of the electrostatic discharge that occurs in the machine,

This is the truth. When it comes to the production environment, it is more difficult. BGA has more than 40 pins corresponding to different circuit blocks. ESD causes various damages, and specialized instruments are difficult. Most of them are exposed by adding TC.

秦天qintian0303

It's good enough if the defective rate of the chip is controlled at 0.2%. If there is a defective chip, just replace it directly.

新不耻下问

If one out of 50,000 pieces is defective, you still have to find the reason. Are you sure it’s not because your boss doesn’t like you? (snickering)

zhangpeggy

新不耻下问 posted on 2023-4-12 10:57 If one out of 50,000 tablets is defective, you still have to find the reason. Are you sure it’s not because your boss doesn’t like you? (snickering)

Probably, maybe not...

ZhuPinchao

Thank you for your attention, welcome to consult and communicate with each other.

Gen_X

If EN is an external input, it should generally be protected.

The absence of problems does not mean that there are no problems with the design. Some designs are meant to be a precautionary measure.