Recommended Reflow Profile
255
230
220
200
180
160
120
80
25
0
P1
HEAT
UP
50
100
P2
SOLDER PASTE DRY
150
200
P3
SOLDER
REFLOW
250
P4
COOL DOWN
300
t-TIME
(SECONDS)
R1
MAX 260C
R3
R4
T - TEMPERATURE (˚C)
R2
60 sec
MAX
Above 220 C
R5
Process Zone
Heat Up
Solder Paste Dry
Solder Reflow
Cool Down
Symbol
P1, R1
P2, R2
P3, R3
P3, R4
P4, R5
DT
25°C to 160°C
160°C to 200°C
200°C to 255°C (260°C at 10 seconds max)
255°C to 200°C
200°C to 25°C
Maximum
∆T/∆time
4°C/s
0.5°C/s
4°C/s
-6°C/s
-6°C/s
The reflow profile is a
straight-line representation of
a nominal temperature profile
for a convective reflow solder
process. The temperature
profile is divided into four
process zones, each with
different DT/Dtime
temperature change rates. The
DT/Dtime rates are detailed in
the above table. The
temperatures are measured at
the component to printed
circuit board connections.
In process zone P1, the PC
board and HSDL-3209
castellation pins are heated to
a temperature of 160°C to
activate the flux in the solder
paste. The temperature ramp
up rate, R1, is limited to 4°C
per second to allow for even
heating of both the PC board
and HSDL-3209 castellations.
Process zone P2 should be of
sufficient time duration (60 to
120 seconds) to dry the solder
paste. The temperature is
raised to a level just below the
liquidus point of the solder,
usually 200°C (392°F).
Process zone P3 is the solder
reflow zone. In zone P3, the
temperature is quickly raised
above the liquidus point of
solder to 255°C (491°F) for
optimum results. The dwell
time above the liquidus point
of solder should be between 20
and 60 seconds. It usually
takes about 20 seconds to
assure proper coalescing of the
solder balls into liquid solder
and the formation of good
solder connections. Beyond a
dwell time of 60 seconds, the
intermetallic growth within the
solder connections becomes
excessive, resulting in the
formation of weak and
unreliable connections. The
temperature is then rapidly
reduced to a point below the
solidus temperature of the
solder, usually 200°C (392°F),
to allow the solder within the
connections to freeze solid.
Process zone P4 is the cool
down after solder freeze. The
cool down rate, R5, from the
liquidus point of the solder to
25°C (77°F) should not exceed
6°C per second maximum. This
limitation is necessary to allow
the PC board and HSDL-3209
castellations to change
dimensions evenly, putting
minimal stresses on the HSDL-
3209 transceiver.
9
AGILENT [ AGILENT TECHNOLOGIES, LTD. ]
