Reflow Profile
MAX. 245°C
R3 R4
230
200
183
170
R2
150
90 sec.
MAX.
ABOVE
183°C
125
100
R1
R5
50
25
0
50
100
150
200
250
300
t-TIME (SECONDS)
P1
HEAT
UP
P2
P3
SOLDER
REFLOW
P4
COOL
DOWN
SOLDER PASTE DRY
Process Zone
Symbol
P1, R1
P2, R2
P3, R3
DT
Maximum DT/Dtime
Heat Up
25°C to 125°C
125°C to 170°C
170°C to 230°C
(245°C at 10 seconds max.)
230°C to 170°C
4°C/s
Solder Paste Dry
Solder Reflow
Cool Down
0.5°C/s
4°C/s
P3, R4
P4, R5
-4°C/s
-3°C/s
170°C to 25°C
Process zone P2 should be of
sufficient time duration (> 60
seconds) to dry the solder paste.
The temperature is raised to a
level just below the liquidus point
of the solder, usually 170°C
(338°F).
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 170°C (338°F), to allow
the solder within the connections
to freeze solid.
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 ∆T/∆time
temperature change rates. The
∆T/∆time rates are detailed in the
above table. The temperatures
are measured at the component
to printed circuit board
Process zone P3 is the solder
reflow zone. In zone P3, the
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
-3°C per second maximum. This
limitation is necessary to allow
the PC board and HSDL-3612
castellation I/O pins to change
dimensions evenly, putting
minimal stresses on the
temperature is quickly raised
above the liquidus point of solder
to 230°C (446°F) for optimum
results. The dwell time above the
liquidus point of solder should be
between 15 and 90 seconds. It
usually takes about 15 seconds to
assure proper coalescing of the
solder balls into liquid solder and
the formation of good solder
connections. Beyond a dwell time
of 90 seconds, the intermetallic
growth within the solder
connections.
In process zone P1, the PC
board and HSDL-3612
castellation I/O pins are heated
to a temperature of 125°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-3612 transceiver.
connections becomes excessive,
HSDL-3612 castellation I/O pins.
14
AGILENT [ AGILENT TECHNOLOGIES, LTD. ]
