Shear strength and Copper/Tin Intermetalic layer

Hi there, I am looking for some informations concerning the shear or pull strength of a typical TQFP 20 mils leads in relationship with the Copper/Tin intermetalic layer thickness. Could anyone help?

Thank in advandce. rgs, chiakl

reply »

| Hi there, | I am looking for some informations concerning the shear or pull strength of a typical TQFP 20 mils leads in relationship with the Copper/Tin intermetalic layer thickness. Could anyone help? | | Thank in advandce. | rgs, | chiakl Chiakl: I don't want to talk intermetalic layers, but I will talk about other things. 1 Amoung things, IPC-TM-650 talks to getting pads off-of boards. For instance: Method 2.4.8 is for peeling copper from laminates. Method 2.4.21 measures peeling cooper pads after multiple rework cycles. 2 I know of no method for ripping leads from pads. 3 The force to peel copper from laminate should be about 6 pound-inch. It will take some where between 4 and 12 pound-inches to get your J-leads from your boards. Good luck Dave F

reply »