Design Guidelines: Pre-deposited Solders

DITF offers pre-deposited and patterned AuSn solder.  On designs with multiple solder hierarchy or multiple pre-form sites, this can be a cost effective way to eliminate pre-forms.  Consult the factory for available thicknesses and other details for applications and design criteria.

Note: The Au/Sn eutectic is a sputtered material (Au,80.4/ Sn,19.52 - Weight %, Typ); which provides superior flatness and thickness control. Typically, sputtered films can replace preforms of 2-3 times the thickness. Sizing of Au/Sn pads is critical and is developed from customer supplied information with respect to die size and tolerance .

Other solders are available on request, please contact our sales team for details

Au/Sn Eutectic Material Properties
Parameter
Value
Units
Composition
80 Au / 20 Sn
Wt %
Melting Temeprature
284.0
°C
Density
14.5
g/cm3
Electric Conductivity
7.7
%IACS
Thermal Conductivity
57.0
W/mk
Temperature Coefficient of Expansion
16.0
m/mK
Resistivity
160.0
n ohm m
Modules of Elasticity
59.0
GPa
Tensile Strength
276.0
MPa
 
Integrated Au/Sn (80/20 wt %) Eutectic Solder
Feature
Value
Tolerance±
Comments
Thickness range
80 - 200 µ"
20 µ"
Most common thickness = 160 µ"
Minimum feature size
.005"
N/A
 
Solder pad pullback from Au metallization
.0015"
N/A
Eutectic pad is inboard of conductor
Au metallization pullback from substrate edge
.002"
N/A
Termination at edge is available, consult factory
Solder pad placement
N/A
.001"
 
Minumum substrate thickness
.005"
N/A
 

 

gold / tin before reflow gold / tin after reflow
gold tin before reflow gold tin after reflow
gold / tin before reflow (close up) gold / tin after reflow (close up)