Guidelines

Packaging Technology

12 Intel

7500 Chipset Thermal Mechanical Design Guide

2.1 Non-Critical to Function Solder Joints

Intel has defined selected solder joints of the IOH as non-critical to function (NCTF)

when evaluating package solder joints post environmental testing. The IOH signals at

NCTF locations are typically redundant ground or non-critical reserved, so the loss of

the solder joint continuity at end of life conditions will not affect the overall product

functionality. Figure 2-4 identifies the NCTF solder joints of the IOH package.

To optimize the mechanical reliability and performance of the Intel 7500 chipset BGA

Intel recommends designing the PCB pad characteristics to be 0.51mm [20 mil]

diameter round copper pads for all non Critical To Function (nCTF) joint locations and

0.46 mm [18 mil] diameter round copper pads for all Critical To Function (CTF) joint

locations.

Figure 2-4. Non-Critical to Function Solder Joints

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35

2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36