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Polymer Collar WLPPolymer Collar™ WLCSP is our patent pending WL-CSP process that is an enhancement to die bumped with the UltraCSP© WLCSP process. In this process, a ring of polymer reinforcement material is added to the base of the bumps during processing. Since the base of the bump receives the most stress during the device lifetime, the addition of the Polymer Collar improves solder joint reliability by up to 50% over the standard UltraCSP process. In addition to having better joint reliability in existing devices, the use of Polymer Collar WLP allows for larger arrays than with standard processing. As with UltraCSP, this process uses the same 250µm- 500µm preformed solder balls. The bumps can be placed directly on the device I/O's or the signal may be redistributed to a more desirable die location. Typically, the number of bumps per die is 4-100. Die bumped with Polymer Collar do not require underfill. |
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