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S. Lee
Table 10.1 Process parameters
Process parameter
Recipe parameter
Comments
Force
(input and response)
Contact force
Contact indicator between bump
and pad
Bond force
Maximum force
Temperature
(input)
Bond head contact temperature
Process material dependent
Bond head peak temperature
Maximum temperature
Bond head release temperature
Sold alloy composition dependent
Bond stage temperature
Process material dependent
Bond head ramp rate
100 °C/s>
Bond head cooling rate
−50 °C/s<
Time
(optional input)
Dwell time at peak temperature of
bond head
Displacement
(input and response)
Melting detection setting
~5 μm
Z-height chase (optional)
Product dependent
~300˚C
~160˚C
High
Low
Fig. 10.14 TCB temperature delta across package between bond head and bond stage
which are maintained at 300 °C and 160 °C respectively. Even though the temperature
of die surface adjacent to heater will be close to 300 °C, solder bumps on the outermost
may hardly reach solder melting point in case of large die packages due to the
large thermal gradient. This is the reason that the heater temperature is set to be
substantially higher than solder melting point in order to ensure melting of the solder
bumps.
The process time is estimated as follows: Assume that the bond head contacts the
die at 200 °C. Upon contact, the temperature is ramped, increases its temperature
with a ramp at a rate of 100 °C/s up to 300 °C. The hold time at the peak temperature
in less than one second. Then, the head, and cools down to 200 °C with a cooling rate