Post on 23-Feb-2016
description
Reliability Issues
Mohammad Sharifkhani
Reading
• Textbook I Chapter 18• Textbook I Chapter 20• The paper on SER
Motivation
• There is a long distance from a chip working in a lab to a chip working in the field
• Reliability• Robustness• Fatigue • Many of the culprits are in rise as technology
scales
Introduction
• Packaging• Electromigration• ESD Protection• SER Protection
Chip Packaging
ChipL
L ´
Bonding wire
Mountingcavity
Leadframe
Pin
•Bond wires (~25m) are used to connect the package to the chip
• Pads are arranged in a frame around the chip
• Pads are relatively large (~100m in 0.25m technology),with large pitch (100m)
•Many chips areas are ‘pad limited’
Pad FrameLayout Die Photo
Chip Packaging• An alternative is ‘flip-chip’:– Pads are distributed around the chip– The soldering balls are placed on pads– The chip is ‘flipped’ onto the package– Can have many more pads
Tristate Buffers
InEn
En
V DD
Out
Out = In.En + Z.En
V DD
In
En
EnOut
Increased output drive
Electromigration• Current density (current per unit area)• A reliability issue creates problem over time– Due to transport of metal ions– AC signals will be fine
• Breaking or shorting to adjacent wire• Keeping current below 0.5 to 1mA/um relaxes the
problem– For DC wires (power/GND)
• IR Drop transient problem (peak current)• Electromigration DC problem (ave. current)• Using copper helps
Electromigration (1)
Limits dc-current to 1 mA/m
Electromigration (2)
Electro-Static Discharge (ESD)
Electro-Static Discharge (ESD)
Electro-Static Discharge (ESD)
Electro-Static Discharge (ESD)
Electro-Static Discharge (ESD)
Electro-Static Discharge (ESD)
Electro-Static Discharge (ESD)
Electro-Static Discharge (ESD)
Electro-Static Discharge (ESD)
Electro-Static Discharge (ESD)
Electro-Static Discharge (ESD)
Electro-Static Discharge (ESD)
Electro-Static Discharge (ESD)
Electro-Static Discharge (ESD)
Electro-Static Discharge (ESD)
Electro-Static Discharge (ESD)
Which one fails?
Electro-Static Discharge (ESD)
Second breakdown of the path at a lower voltage than the second break-down of the ESD path
Second breakdown of the path at a higher voltage level than the second break-down of the ESD path
Electro-Static Discharge (ESD)
Electro-Static Discharge (ESD)
Electro-Static Discharge (ESD)
Electro-Static Discharge (ESD)
Electro-Static Discharge (ESD)
There are challenges as technology scales!
Electro-Static Discharge (ESD)
Electro-Static Discharge (ESD)
Electro-Static Discharge (ESD)
Electro-Static Discharge (ESD)
Electro-Static Discharge (ESD)
Design of ESD protection circuits:A glimpse!
Electro-Static Discharge (ESD)
Electro-Static Discharge (ESD)
Electro-Static Discharge (ESD)
Electro-Static Discharge (ESD)
• ESD protection is extremely important when dealing with high speed input output signals• I/O Capacitance
Soft Error
Soft Error
Soft Error
Soft Error
Soft Error
Soft Error
Soft Error
Soft Error
Soft Error
Soft Error
Soft Error
Soft Error
Soft Error
Soft Error
Soft Error
Soft Error
Soft Error
Soft Error
Soft Error
Soft Error
Soft Error