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Managing Lead and LeadFree Transition

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Title: Managing Lead and LeadFree Transition


1
Managing Lead and Lead-Free Transition
  • Dr. Sudarshan Lal
  • FCI USA, Inc.
  • Etters, PA (USA)
  • June 20, 2002

2
Outline
  • Introduction
  • Lead-free test plans
  • Lead-free implementation for
  • i) Pressfit ii) Reflow iii) BGA Applications
  • Test status
  • Conclusions

3
Market Segment Requirements
  • Commercial 2003
  • Industrial Not Clearly Defined
  • Computer 2003
  • Telecom/Backpanel Not Clearly Defined
  • Board and connector performance issues are the
    cause for a less defined need in the
    Telecom/Backpanel market

Request for segment data made to fleck and bishop
4
Regions Timing Requirements
  • Americas Not Clearly Defined
  • A/P 2003 (Some Appliances in Japan)
  • Europe 2006 (Servers Auto. 2010)
  • Although there is no legislation, pending or
    otherwise, Japan is calling for the reduction or
    elimination of lead in Electronics. Several
    Japanese OEMs have taken it upon themselves to
    be as proactive in this market as possible

5
Timing Requirements Europe A/P
  • The use of lead in electronics assembly within
    the European Union will be banned after January
    2008 (and possibly as soon as 2006). Servers and
    Automotive exempted until 2010
  • Since A/P, specifically Japan, is the first
    regional area to require lead-free products,
    FCIs lead-free implementation will be heavily
    influenced by the needs and requirements of major
    Japanese OEM customers.

SourceEnvirowise Website http//www.envirowise.go
v.uk
6
Lead-Free Global Team Charter
  • Provide leadership, coordination, and
    communication to FCI Worldwide to implement a
    lead-free offering of our products where
    appropriate in a way that
  • Identifies marketing and customer expectations
  • Establishes product conversion priority and
    timing
  • Provides leadership and communication
  • Coordinates activities with the other regions
  • Provides technology solutions for our products
  • Assures the generation and communication of
    technical support data, and
  • Generates an implementation plan that includes
    sales, marketing, engineering, manufacturing, and
    technology actions and timing
  • so that FCI can provide a lead-free product
    offering that meets the needs of our customers in
    a timely manner and meets our business
    objectives.

7
Lead-Free Team Methodology
Rather than focus on 40 product lines, the
lead-free team will focus on the three main
termination styles. Each termination style
will have a different technical solution or a
significantly different performance or whisker
issue that needs solving.
8
Implementation By Termination Style
Thru-Hole
SMT
BGA Termination
Reflow
Press-Fit
9
Advantages of Sn-Cu v. Sn coating
  • Aesthetically superior bright deposit with low
    carbon stable alloy composition
  • Sn-Cu is less prone to whiskering than pure tin .
    Alloying helps in whisker mitigation
  • Low foam, stable solution without strong odors
    for Sn-Cu bath
  • Plated Sn-Cu film resistant to discoloration in
    heat tests
  • Solderability for Sn-Cu coating is equivalent or
    better than Sn-Pb and pure tin finishes. Tin
    coatings after steam aging exhibited poor
    solderability (longer wetting times, negative
    forces)

10
Technical Solution
Press-Fit Reflow Sn-Cu Plating ( Bath
Globally Available) BGA Sn-Cu-Ag Spheres
(Spheres Globally Available) Note FCI Searching
Lead-Free Epoxy to Withstand 260 C
11
Press-Fit Lead-Free Implementation Flow Chart
Perform DOE And Test Plan Utilizing Multiple
Boards
Connector Technical Solution Sn-Cu Plating
Test Boards Immersion Ag Immersion Sn Bare
Cu/OSP Tin/Lead Nickel Gold
Confirm Technical Solution In Press-Fit
Applications
12
Lead-Free Press-Fit Test Plan
  • Utilizing a Metral EON press-fit pin
  • Testing conducted with Tin-Lead, OSP, ImAg,
    ImSn, Ni-Au Boards
  • Telecom UE Tests
  • Vibration Shock 50 Contacts Min. Max. PTH
    Board
  • Thermal Shock/Humidity 50 contacts Min.
    Max. PTH Board
  • Mixed Flow Gas 25 Contacts Max. PTH Board
    Only
  • Repair (Insertion/Retention, Heat Age, Hole
    Deformation) 150 Contacts Min. Max. PTH Board

13
Press-Fit Test Results Status
  • Vibration Shock No abnormalities found
  • Thermal Shock/Humidity test In Progress
  • Mixed Flow Gas Initial Preparation Completed.
    Going to MFG chamber
  • Repair (Insertion/Retention, Heat Age,
    Hole-size) Passed within normal limits
  • Compliant pin resistances were within
    specifications (less than 1 milliohm)

14
BGA Implementation Flow Chart
Perform DOE And Test Plan Utilizing Copper Board
Connector Technical Solution SnCuAg BGA
Test Boards Bare Cu/OSP
Confirm Technical Solution In BGA Applications
15
Lead-Free BGA Test Plan
  • Test PCB Pad Plating OSP (Cu with Coating)
  • 1.) Thermal Shock Testing Per MEG-Array Product
    Spec GS-12-100
  • 2.) Solder Joint Tensile Strength 3-Point Bend
    Testing per MEG-Array Product Specification
    GS-12-100 2a. Solder ball pull strength.
  • 3.) Solder Wicking Evaluation
  • 4.) Thermal Cycling per IPC-SM-785 (Telecom
    Central Office Environment)

16
Lead-Free BGA Test Results
  • Passed three-point bend test. No dye penetration
    observed. Micro-cracks were absent
  • Lead-free solder tensile strength was greater
    than standard Tin-lead solder
  • Solder joint reliability was equivalent to
    Tin-lead

17
Re-flow Termination Implementation Flow Chart
Perform DOE And Test Plan Utilizing Copper Board
Connector Technical Solution Sn-Cu Plating
Test Boards Bare Cu/OSP
Confirm Technical Solution In Re-flow Applications
18
Lead-free Re-flow Test Status
  • Solderability was excellent exhibiting normal
    forces and percentage coverage comparable to
    Tin-lead
  • Tensile Strength using Instron was similar to
    Tin-lead
  • Whisker tendency not studied yet. Reflow should
    minimize whisker formation
  • Need to develop plan for i) Bergstik-thruhole
    ii) Bergstak-SMT iii) Memory-SMT Products

19
Resins Molding For Lead-Free
Three resins failed to withstand the industry
anticipated 260C peak re-flow temperature for
lead free soldering. These resins are
LCP A (280C) (Baby HMetral
Headers) PPS (Card Edge Press-Fit) SPS (GBIC
SMT) Polyamide 46 Polyphthalamide high
temperature nylons passed at all re-flow
temperatures in the dry state, but failed at all
re-flow temperatures (even the current 223C) in
the wet state via blistering. The failures were
due to the hygroscopic property of the material
and not the re-flow temperature.   In general,
those materials with a melting point of 285C and
lower exhibited visual and/or dimensional defects
following exposure to 260C and higher re-flow
temperatures. All resins with melting points
greater than 285C successfully sustained the
industry anticipated 260C peak re-flow profile
without visual/dimensional damage.
Converged EON Metral Headers Use LCP E Melt
Temp 335C
20
Existing FCI Lead-Free Products
21
Conclusions
  • FCI maintains an open dialogue with suppliers,
    contract manufacturers, OEMs and consortia
    regarding lead-free technical solutions.
    Presently customers are interested in plans ,
    capabilities and limited test samples
  • The global lead-free team is in the process of
    identifying testing lead-free solutions for
    BGA, press-fit re-flow products
  • Implementation and smooth transition shall be
    case-by- case based on credible scientific data
    of proven reliability, market demand, regulatory
    compliance, supply assurance, quality and
    competitive cost
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