IT3/IT5
Connector System
T
IPS FOR
SMT
A
SSEMBLY
Document Number:
ETAD-F0458
Revision 3.10
Page
57
of
73
Head-In-Pillow Defect,
Ball-on-pin style BGA
Notice how the ball gets offset from the
solder and pad under HIP condition
Opens:
Solder opens
occur whe n the conne ction be twee n a ball and a pad is not comple ted.
S
o
ld
e
r
O
p
e
n
s
Possible Cause
Suggested Action
Poor solde r paste pri nt
Che ck pas te print quali ty
De vi ce wa rpage lifting balls out of
pas te
Shorte n ti me to reach liquidus by ramping
fas te r or limi ting soak ti me
Re flow profile not rea ching high
enough peak tempe ra ture , resul ting
in cold joints
Increase peak tempe ra ture and/or time
above liquidus
Head-In-Pillow (HIP):
de fe cts gene rall y occur whe n:
•
The solde r pas te deposi t on the boa rd mel ts and fuses toge the r in the re flow oven
•
The solde r sphe re on the BGA also mel ts in the re flow oven
•
The sphe re ma te rial and solde r de posi t
do not
fuse toge the r to be come one contiguous
mass .
Typi call y, the reason the y do not fuse toge the r
is be ca use one or both of the mol ten masses
a re cove re d with a thin but tough film of oxide
tha t pre vents them from mingling wi th ea ch
othe r. This oxi de film is often forme d in the
re flow process by one or more contributing
fa ctors .
Note tha t the HIP defe ct mode has a slightl y
di ffe rent appea rance on ball-on-pin s tyle BGA
components than i t does on ball-on-pad s tyle
components .
H
e
a
d
-I
n
-P
ill
o
w
Possible Cause
Suggested Action
Re flow profile taking too long to
rea ch liquidus tempe ra ture ,
e xha usting the flux
Shorte n ti me to reach liquidus by ramping
fas te r or limi ting soak ti me
Compone nt body wa rpa ge lifting
balls out of pas te
Shorte n ti me to reach liquidus by ramping
fas te r or limi ting soak ti me
Surface a rea :volume ra tio of paste
de posit enables flux e xhaustion
Increase diame te r of ste ncil ape rture to
0.6mm.
Nov.1.2022 Copyright 2022 HIROSE ELECTRIC CO., LTD. All Rights Reserved.
