form its phase from solid to
liquids. The dwell time at melting The recommended solder paste is
point 183°C shall maintain at type Sn6337A or Sn60Pb40A of
between 60 to 150 seconds. Upon J-STD-006.
Solder Paste
Zone 1 – Preheat Zone
The average heat up rate for
surface-mount component on
PCB shall be less than 3°C/
second to allow even heating for
both the component and PCB.
This ramp is maintained until it
reaches 100°C where flux
activation starts.
Note: Solder paste storage and shelf
the duration of 10-20 seconds at
peak temperature, it is then
cooled down rapidly to allow the
solder to freeze and form solid.
life shall be in accordance with
manufacturer’s specifications.
Stencil or Screen
The solder paste may be depos-
ited onto PCB by either screen
printing, using a stencil or
syringe dispensing. The recom-
mended stencil thickness is in
accordance to JESD22-B102-C.
Extended duration above the
solder melting point can poten-
tially damage temperature
sensitive components and result
in excessive inter-metallic growth
that causes brittle solder joint,
weak and unreliable connections.
It can lead to unnecessary dam-
age to the PC Board and discol-
oration to component’s leads.
Zone 2 – Soak Zone
The flux is being activated here
to prepare for even and smooth
solder joint in subsequent zone.
The temperature ramp is kept
gradual to minimize thermal
mismatch between solder, PC
Board and components. Over-
ramp rate here can cause solder
splatter due to excessive oxida-
tion of paste.
Zone 4 – Cooling Zone
The temperature ramp down rate
is 6°C/second maximum. It is
important to control the cooling
rate as fast as possible in order
to achieve the smaller grain size
for solder and increase fatigue
resistance of solder joint.
Zone 3 – Reflow Zone
The third process zone is the
solder reflow zone. The tempera-
ture in this zone rises rapidly
from 183°C to peak temperature
of 235°C for the solder to trans-
Nominal stencil thickness
Component lead pitch
0.102 mm (0.004 in)
0.152 mm (0.006 in)
0.203 mm (0.008 in)
Lead pitch less than 0.508 mm (0.020 in)
0.508 mm to 0.635 mm (0.02 in to 0.025 in)
Lead pitch greater than 0.635 mm (0.025 in)
www.agilent.com/semiconductors
For product information and a complete list of
distributors, please go to our web site.
For technical assistance call:
Americas/Canada: +1 (800) 235-0312 or
(916) 788-6763
Europe: +49 (0) 6441 92460
China: 10800 650 0017
Hong Kong: (65) 6756 2394
India, Australia, New Zealand: (65) 6755 1939
Japan: (+81 3) 3335-8152(Domestic/International), or
0120-61-1280(Domestic Only)
Korea: (65) 6755 1989
Singapore, Malaysia, Vietnam, Thailand, Philippines,
Indonesia: (65) 6755 2044
Taiwan: (65) 6755 1843
Data subject to change.
Copyright © 2004 Agilent Technologies, Inc.
Obsoletes 5989-0403EN
November 10, 2004
5989-1899EN
AGILENT [ AGILENT TECHNOLOGIES, LTD. ]
