10 Fundamentals of Bonding Technology and Process Materials …
295
Simulation or
Historical baseline
Material formulation
design and
characterization
Preliminary material properties meeting
reliability and wetting performance
→Tg, Viscosity, Modulus, Filler concentration, and etc.
Wetting study
Void study
Process parameters
investigation
Process optimization
Process and reliability
validation
Material formulation optimization
using test coupons
Process development
using target test vehicles
Fig. 10.41 Flowchart of material formulation characterization
First, simulation and historical data will define basic material properties such as
Tg, viscosity, modulus, filler concentrations, etc. Note that the material properties
are dependent so that compromises will be made to optimize them for the package
configuration. According to the preliminary results, material formulation is designed
to meet initial reliability and process requirements. Next, metrology techniques are
used to characterize the behavior of the materials under thermal conditions replicating
an actual process. Then, fundamental investigations that are designed to examine
wetting and voiding will provide baseline process parameters on TCB HVM. The
preliminary process parameters are optimized to meet process requirements in terms
of voids and process yield and the optimal process parameters are validated using a
large number of test vehicles, which is equal to or greater than a statistically significant sample size. Reliability tests follow to confirm long-term performance. The
forementioned systematic studies provide the most effective method to demonstrate
a high volume, stable assembly process while also reducing the number of iterations
towards that objective.
295
Simulation or
Historical baseline
Material formulation
design and
characterization
Preliminary material properties meeting
reliability and wetting performance
→Tg, Viscosity, Modulus, Filler concentration, and etc.
Wetting study
Void study
Process parameters
investigation
Process optimization
Process and reliability
validation
Material formulation optimization
using test coupons
Process development
using target test vehicles
Fig. 10.41 Flowchart of material formulation characterization
First, simulation and historical data will define basic material properties such as
Tg, viscosity, modulus, filler concentrations, etc. Note that the material properties
are dependent so that compromises will be made to optimize them for the package
configuration. According to the preliminary results, material formulation is designed
to meet initial reliability and process requirements. Next, metrology techniques are
used to characterize the behavior of the materials under thermal conditions replicating
an actual process. Then, fundamental investigations that are designed to examine
wetting and voiding will provide baseline process parameters on TCB HVM. The
preliminary process parameters are optimized to meet process requirements in terms
of voids and process yield and the optimal process parameters are validated using a
large number of test vehicles, which is equal to or greater than a statistically significant sample size. Reliability tests follow to confirm long-term performance. The
forementioned systematic studies provide the most effective method to demonstrate
a high volume, stable assembly process while also reducing the number of iterations
towards that objective.