Failure Analysis with Fred Femto Field (Part 2)

Failure Analysis: Something about DALS

Hi my dear photons! It's me, Fred Femto Field! How are you doing today?

Just got back from the Quantic world, and I was feeling in the mood for a small article about DALS (Dynamic Analysis by Laser Stimulation).

If you didn't follow the last post on Failure Analysis, you can always check it here.

So... DALS, is mainly used for Soft Defects, they are subtle defects that causes a device to be only partially functional and it might not operate under certain conditions. SDL (Soft Defect Localization) is a collection of various laser scanning isolation techniques, DALS (Dynamic Analysis by Laser Stimulation) is one among them.

The DUT (Device Under Test) is stimulated using a 1.3 µm laser, that it is scanning the entire surface, pixel by pixel, while it is operating under normal conditions. During the scan, there is production of photoelectric and photothermal effects on the device, resulting to thermal energy production (heat), that creates electrical variation on the DUT.

Source: Ref. 1

If an oscilloscope is connected to the later, we can see that at a normal pixel no change is transferred to the oscilloscope. At an abnormal pixel, change is transferred to the oscilloscope and a pulse is captured by the DALS system.

The DALS system will lead the image system to mark a spot on the screen. By superimposing it on the DUT’s pattern, it is possible to see where the abnormal spot is located.

Source: Ref.2 (left) and Ref.3 (right)

Pretty cool right?!

So stay toned! I'll be continuing with the series pretty soon! I wish you all an amazing day!

Cheers from 10^-15 !!

(For the ones who want to know more about the aim of the blog, you can always click here)

References:

1 - F. Beaudoin, K. Sanchez, P. Perdu, “Dynamic laser stimulation techniques for advanced failure analysis and design debug applications” Microelectronics Reliability, vol 47, pp. 1517-1522, November 2007.

2 - H. Chi, F. Diwei, S. Grace, “SDL analysis in temperature sensitive failure based on DALS system”, In Proc. IEEE International Symposium on the Physical and Failure Analysis of Integrated Circuits (IPFA), 2017.

3 -P. Hubert, C. Joyce, K. Kaye, “Soft Defect Localization of Hot Failure by Dynamic Analysis by Laser Stimulation using Hamamatsu iPhemos", In Proc. IEEE International Symposium on the Physical and Failure Analysis of Integrated Circuits (IPFA), 2018.