Question

Quiz on Reliability, ESD, Ethics Conduct. Select the correct answer for each

a) How is a product expected to fail after a very long time in use?

-Metal electromigration will short out the power supply

-Wearout

-MOS gate oxide will burst

-Electrical overstress

-The "divide" function will start losing bits randomly

b) Is there an issue preventing continuous improvement for better reliability in manufacturing?

-Customers who design high reliability products with your semiconductor parts will not allow substantial changes in manufacturing once the process is released

-No, customers demand continuous process improvement and lower price regardless of what needs to be changed

-Once the process achieves Six Sigma qualification on 3 parameters, no further change is permitted

-Customers expect the manufacturer to buy newer equipment every year to improve product reliability

-Manufacturers can always change the specification limits, but are not permitted to reduce variation

c) Explain HBM ESD?

-System power is cycled off to drain the charge, then the human accumulates an equivalent charge

-A cable connects from a human to the test board, causing a visible arc

-The semiconductor part is charged, and then zaps itself when metal contact is made

-Charged person grounds herself through a wriststrap, causing a fast discharge

-Charged person makes electrical contact with metal of a semiconductor part, causing a fast discharge

d) Why is prevention of CDM a high priority among manufacturers?

-VDM discharges can be so fast that even a small amount of stored charge can cause damage, and discharge may happen multiple times

-The slow discharge tends to drain batteries without you knowing it

-CDM occurs at so much higher voltage than HBM that it's much more dangerous

-Rules for prevention of CDM are more difficult and cost much more money to implement

-It's embarrassing when your customers find out that you have the same problem as them

Answer 1

a) How is a product expected to fail after a very long time in use?

Ans: Metal electromigration will short out the power supply.

It is the material transport due to the gradual movement of ions because of momentum transfer among conducting electrons. It is also caused due to diffusing metal atoms.

Electromigration cause loss of connection in the circuits and will short out the supply to undesired routes.

b) Is there an issue preventing continuous improvement for better reliability in manufacturing?

Ans: No, customers demand continuous process improvement and lower price regardless of what needs to be changed

But a strong process discipline should be taken up. Cost reduction is always a significant parameter in manufacturing.

c) Explain HBM ESD?

Ans: a Charged person makes electrical contact with the metal of a semiconductor part, causing a fast discharge. HBM ESD is caused by a charged human discharging current into the IC ground. This is the most common model used to characterize susceptibility of device damage from ESD.

d) Why is the prevention of CDM a high priority among manufacturers?

Ans: CDM occurs at so much higher voltage than HBM that it's much more dangerous. CDM currents are higher in comparison to the human body model current because there is no resistor into the path to control the discharge.

The charge device model (CDM) represent electronic discharge when charged integrated circuits during manufacturing comes in contact with the grounding network.