Root Cause of Backside Chipping in Wafer Saw

EESemi.com Forum Archives

'Backside Chipping' refers to the failure attribute characterized by the presence of chipping along the edges of the back surface of the die after wafer saw. Thus, instead of a clean cut resulting from the wafer saw operation, the backside of the die will have rough edges caused by small chips having been mechanically broken off and dislodged from various parts of the backside edges. This is an indication of a stressful sawing operation that can lead to reliability issues like die cracking, so signs of backside chipping after wafer sawing must be promptly addressed. The archived forum thread below discusses how backside chipping resulting from improper wafer saw can be resolved.

Posted by Donnie: Wed Nov 08, 2006 2:48 am Post subject: root cause of backside chipping in wafer saw?

please , I need inputs from the experts here.
water resistivity = 0.3 to 1.0 M ohm

the current blade we use is disco
cutting method = step cut
z1 = 27hccc
z2 = 27hccb
cut height 1 = 230um
cut height 2 = 65 um
cutting speed = 60 mm/s
wafer thickness reqmt = 250um
dicing tape thick = 90um
machine used = TSK A-WD-200T
========================
the current blade we use is disco
cutting method = single or dual cut
z1 = 27heed
z2 = 27heed
cut height 1 = 65um
cut height 2 = 65 um
cutting speed = 40-60 mm/s
wafer thickness reqmt = 250um
dicing tape thick = 90um
machine used = disco dfd6361

thanks.
_________________
PACLANDER

Posted by Jarod: Wed Nov 08, 2006 8:09 am Post subject:

You can try checking out the response of those variables through design of experiment.

Posted by Balapmurugan: Fri Nov 10, 2006 1:50 pm Post subject:

Hope the wafer is normal after detaping after backgrind process.

What is the die size ? Do you heat the mounted wafer to improve the adhesion (Oven cure / Hot plate cure). Try to do hotplate cure for 3 to 4 Minutes prior to cutting.

What is your blade dressing procedure. I hope during the dressing procedure with dresser boards you perform atleast 5 to 10 cuts for every 500 mils/ sec increment until 3000 mils /sec.

You need to adjust your cut height 1 & cut height 2. Always use the guideline that the first blade cut depth is one third of the total thickness. The second blade need to cut the balance & one or two mils in tape. Also the first blade width slightly in excess of the second blade.

If you still have problems, report the problems to Disco, as you use their machine & blade and they have very good application center who can provide blades with different grit size, nickel bond hardness and concentration.

Hope this helps & good luck.

Bala.

Posted by Donnie: Sun Nov 12, 2006 3:49 am Post subject:

Dear Sirs,
Thank you very much for the inputs. Now, I will do
the evaluations for this.
_________________
PACLANDER

Back to the 'Best of Forums' Archives

HOME