For product information and a complete list of distributors, please go to our web site: www.avagotech.com
Avago, Avago Technologies, and the A logo are trademarks of Avago Technologies, Pte. in the United States and other countries.
Data subject to change. Copyright © 2006 Avago Technologies Pte. All rights reserved. Obsoletes 5989-1899EN
AV01-0038EN - February 22, 2006
Nominal stencil thickness Component lead pitch
0.102 mm (0.004 in) Lead pitch less than 0.508 mm (0.020 in)
0.152 mm (0.006 in) 0.508 mm to 0.635 mm (0.02 in to 0.025 in)
0.203 mm (0.008 in) Lead pitch greater than 0.635 mm (0.025 in)
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.
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 oxidation of paste.
Zone 3 – Reflow Zone
The third process zone is the solder reflow zone. The
temperature in this zone rises rapidly from 183°C to
peak temperature of 235°C for the solder to transform
its phase from solid to liquids. The dwell time at
melting point 183°C shall maintain at between 60 to
150 seconds. Upon the duration of 10-20 seconds at
peak temperature, it is then cooled down rapidly to
allow the solder to freeze and form solid.
Extended duration above the solder melting point can
potentially 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 damage to the PC Board
and discoloration to component’s leads.
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.
Solder Paste
The recommended solder paste is type Sn6337A or
Sn60Pb40A of J-STD-006.
Note: Solder paste storage and shelf life shall be in
accordance with manufacturer’s specifications.
Stencil or Screen
The solder paste may be deposited onto PCB by either
screen printing, using a stencil or syringe dispensing.
The recommended stencil thickness is in accordance
to JESD22-B102-C.
