Keysight LPDDR4, Руководство по установке

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Keysight W6600A-series LPDDR4 BGA Interposers Installation Guide 33
Interposers and Riser Soldering Guidelines 4
Recommended Soldering Guidelines
These guidelines are intended for anyone who has decided to install the winged / rigid BGA
interposers themselves, or would like to provide guidelines to their regular contract manufacturer.
• The W6600A-series interposers are assembled using lead free or leaded soldering processes.
• Observe standard lead-free rework guidelines and processes when applying LPDDR memory
devices and attaching a riser to an interposer and DIMM.
• Typical time-above-liquidus (220°C in the case of SAC305 solder) is 30 to 90 seconds with 60
seconds as the good nominal target.
• The peak temperature at the SAC305 solder joints should be a minimum of 235°C.
• It is best to limit the peak temperature on the package of the IC at a maximum of 245°C.
• To minimize heating effects on components mounted on the interposer assembly, a leaded solder
process can be used to attach a riser, when it is compatible with your prototype debug and
validation methodologies.
• The maximum processing temperature that the W6600A-series interposers can withstand is 260
°C for not more than 90 seconds.
• The W6600A-series interposers are supplied without solder balls. Depending on the exact
attachment order, either leaded or lead-free solder may be preferred to attach the interposer to
the DUT. The design of the interposer supports either choice.
Applicable only to the winged interposers in the series such as the W6601A interposer
• The flex wings on Keysight BGA interposers are made with Pyralux AP, the flex material, and
Pyralux FR, the coverlay material with adhesive. Both of these materials have high moisture
absorption characteristics, and always require baking prior to processing. Review the DuPont
baking recommendation before processing.
• The flexible “wings” on the interposer may need to be bent upwards before soldering to avoid
mechanical contact with components adjacent to the interposer on the DUT. If interposer wings
are bent during the soldering process, precautions must be taken to ensure that the wings do not
move during the process. Applying heat to a bent wing has the tendency to cause the wing to
relax and this can result in movement during the soldering process that can damage the integrity
of the solder joints.