Posted by Zurita: Wed Sep 20, 2006 9:21 am    Post subject: die attach reliability test

can anyone help me..
I want to know what reliability test is done for die attach process.
and another question is what is the purpose of reflow process at 260 deg C for lead free solder. why must 260 deg C? thanks in advance.

Posted by FARel Engr: Wed Sep 20, 2006 2:39 pm    Post subject:

Hi Zurita,

For a new die attach process, you need to do all the major rel tests: SHRT, Temp Cycle, Thermal Shock, Autoclave Test, and HAST. And if this is for a hermetic package, you also need to do the usual mechanical tests - constant acceleration, etc.

Lead-free reflow is done at 260 deg C because that is the temp required for board-mounting parts that use lead-free solder. Note that lead-free solders melt at a higher temp than Pb-Sn solder, which is reflowed at just 220-230 deg C.

FARel Engr

Posted by Zurita: Mon Nov 06, 2006 12:24 pm    Post subject:

thanks for the info. but where can i get the details about HAST, Autoclave test,SHRT.. I'm doing my thesis on topic "Study on impact of different Pb-free solder die attach composition on product performance and reliability" my thesis is not an experiment based it just literature so i need more information for me to understand details about solder die attach.
i had read on few articles about die punch test, C-SAM, shear test. is it also the major test for die attach process?
is it plastic package and hermatic package also can use solder as the adhesive for die attach or solder only can be applied to copper/ silver lead frame?

Posted by Rivs: Sat Jul 07, 2007 8:55 am    Post subject:

Hi,

In addition you can also perform IOL. Intermittent Operating Life which is used to determine the integrity of the die attach of device assembly by cycling the device on thermal heating of the junction due to conduction and off cooling due to removal of power, external device cooling necessary to achieve in junction temperature typically 100°C or greater.

Posted by Jaec: Sun Jul 08, 2007 12:15 pm    Post subject:

Hi!

It would be good to know also the method you use for die attach: the material you use and the machine you use. Then you would know what failure mechanism you should watch out: chemical, mechanical... and analyze whether it is related to the die attach process.

Jaec
_________________
Jessica M. Castillo
Failure Analysis Consultant
Sigmatech Inc. Phils.

Posted by mel_c: Fri Jul 13, 2007 10:16 pm    Post subject:

hi zurita,

visit JEDEC.org and look for JESD47-STRESS-TEST-DRIVEN QUALIFICATION OF INTEGRATED CIRCUITS. This jedec standard guides you to design reliability qual plan for different major changes (also defined in that document) such as change in DA material. This specs also discuss the sampling plan and criteria to declare a qual pass or fail.
_________________
mel_c