Recommended Reflow Profile
255
230
220
200
180
160
120
80
25
0
P1
HEAT
UP
50
100
P2
SOLDER PASTE DRY
150
t-TIME (SECONDS)
P3
SOLDER
REFLOW
P4
COOL
DOWN
200
250
300
R1
MAX. 260°C
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
DT/Dtime
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 con-
vective 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 tempera–
tures are measured at the
component to printed circuit
board connections.
In
process zone P1,
the PC
board and HSDL-3005
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-3005
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-3005
castellations to change
dimensions evenly, putting
minimal stresses on the HSDL-
3005 transceiver.
13
AVAGO [ AVAGO TECHNOLOGIES LIMITED ]
