Component Terminal Finishes Phase 3

This project measures MSL results by surface treatment type and development results of new NiPd-based finishes for enhanced MSL, based on the results presented in Phases I and II.  Data includes the use of surface treatments and finishes such as Cu surface Zn-Cr coating (A2 coating), Micro Etching, Brown Oxidation Treatment and Surface Adhesion Promoter Coating.

Project stage: 
Project type: 

Idea Information

Background: 

This project measures MSL results by surface treatment type and development results of new NiPd-based finishes for enhanced MSL, based on the results presented in Phases I and II.  Data includes the use of surface treatments and finishes such as Cu surface Zn-Cr coating (A2 coating), Micro Etching, Brown Oxidation Treatment and Surface Adhesion Promoter Coating.

Problem: 

While an improved technology that overcomes the technical and cost issues of convention NiPd-based finishes has been developed and applied extensively, degradation in the Moisture Sensitive Level (MSL) of a package component due to the increase in Pb-free SMT temperature (260C) has occurred more frequently with NiPd-based finish packages.  As a result, component users have been hesitant to apply NiPd-based finishes.  Various mitigation/amelioration techniques have been proposed to reduce the Sn-whisker risk with matte Sn finishes.

Definition Information

Approach: 

Nevertheless, most end users of electronic components (system integrators and EMS providers) still have concerns about long term Sn-whisker growth risk with Sn based termination finishes.  NiPd-based pre-plated lead frame (PPF) finishes have been introduced as one Pb-free alternative with no Sn-whisker risk.

Scope of Phase 3

  • Provide MSL, Moisture Sensitivity Level, information of Pb-free solutions because the market needs of high reliability applications such as server, automotive, communication, etc. is increased very much.
  • Evaluate MSL performance of Pb-free surface finishes, Matte tin, NiPdAu, NiPdAu-alloy, etc. to give better surface finish choices to the package user group.

Preparation for Phase 3

  • Samsung, Amkor and TI agreed on scope
  • Define deliverables
  • Design experiment
  • Enlist/define A/T sites
  • Assemble BOM - supplier support
  • Enlist MSL test sites
  • Refine time line

Factors to Consider - BOM A/T

  • Leadframe
    • Package thickness, die pad size, down set depth, exposed pad
    • QFP, QFN, SOIC, and/or TSOP
    • At least one with exposed pad
  • Leadframe Finish
    • Ag spot, u-PPF, upgrade u-PPF, NiPdAu, rough surface treatment
    • Mold compound, Die attach - focus on common BOM and minimize test legs
  • Die - dummy or functional